CA2567724A1

CA2567724A1 - Method for at least partially compensating for errors in ink dot placement due to erroneous rotational displacement

Info

Publication number: CA2567724A1
Application number: CA002567724A
Authority: CA
Inventors: Simon Robert Walmsley; Kia Silverbrook; Mark Jackson Pulver; John Robert Sheahan; Richard Thomas Plunkett; Michael John Webb; Benjanim David Morphett
Original assignee: Silverbrook Research Pty Ltd; Simon Robert Walmsley; Kia Silverbrook; Mark Jackson Pulver; John Robert Sheahan; Richard Thomas Plunkett; Michael John Webb; Benjanim David Morphett
Current assignee: Silverbrook Research Pty Ltd
Priority date: 2004-05-27
Filing date: 2004-05-27
Publication date: 2005-12-22
Also published as: EP1765595A4; AU2009203027A1; EP1765595B1; AU2009203031A1; AU2009203028A1; AU2009203033A1; AU2008207608B2; AU2009203025B2; AU2009203032B2; AU2008207608A1; PT2301753E; WO2005120835A1; EP1765595A1; AU2009203031B2; AU2009203033B2; AU2009203027B2; AU2009203026B2; AU2009203026A1; AU2009203015B2; EP2301753B1

Abstract

A method of at least partially compensating for errors in ink dot placement by at least one of a plurality of nozzles due to erroneous rotational displacement of a printhead module relative to a carrier, the nozzles being disposed on the printhead module, the method comprising the steps of: (a) determining the rotational displacement; (b) determining at least one correction factor that at least partially compensates for the ink dot displacement; and (c) using the correction factor to alter the output of the ink dots to at least partially compensate for the rotational displacement.

Description

DEMANDE OU BREVET VOLUMINEUX

LA PRESENTE PARTIE DE CETTE DEMANDE OU CE BREVET COMPREND
PLUS D'UN TOME.

NOTE : Pour les tomes additionels, veuillez contacter le Bureau canadien des brevets JUMBO APPLICATIONS/PATENTS

THIS SECTION OF THE APPLICATION/PATENT CONTAINS MORE THAN ONE
VOLUME

NOTE: For additional volumes, please contact the Canadian Patent Office NOM DU FICHIER / FILE NAME:

NOTE POUR LE TOME / VOLUME NOTE:

Method for at least partially compensating for errors in ink dot placement due to erroneous rotational displacement FIELD OF THE INVENTION

The present invention relates to a method of compensating for errors in ink dot placement due to erroneous rotational displacement of a printhead or printhead module.

The invention has primarily been developed for use in a pagewidth inkjet printer comprising a printer controller and a printhead having one or more printhead modules, and will be described with reference to this example.
However, it will be appreciated that the invention is not limited to any particular type of printing technology, and is not limited to use in, for example, pagewidth and inkjet printing.

CROSS-REFERENCES
Various methods, systems and apparatus relating to the present invention are disclosed in the following co-pending applications filed by the applicant or assignee of the present invention. The disclosures of all of these co-pending applications are incorporated herein by cross-reference.

10/727,181 10/727,162 10/727,163 10/727,245 PEA05US
10/727,233 10/727,280 10/727,157 10/727,178 10/72,210 PEAI1US 10/727,238 10/727,251 10/727,159 10/727,180 PEA16US PEA17US PEA18US 10/727,164 10/727,161 10/727,198 10/727,158 10/754, 53 6 10/754, 93 8 10/727,227 10/727,160 09/575,108 10/727,162 09/575,110 09/607,985 6,398,332 6,394,573 6,622,923 10/173,739 10/189,459 10/713,083 10/713,091 ZG164US 10/713,077 10/713,081 10/713,080 10/667,342 10/664,941 10/664,939 10/664,938 10/665,069 09/112,763 09/112,762 09/112,737 09/112,761 09/113,223 09/505,951 09/505,147 09/505.952 09/517,539 09/517,384 09/516,869 09/517,608 09/517,380 09/516,874

2 09/517,541 10/636,263 10/636,283 ZE028US ZE029US

ZE030US 10/407,212 10/407,207 10/683,064 10/683,041 Some applications have been listed by their docket numbers, these will be replaced when application numbers are known.

BACKGROUND
When a printhead module is being mounted to a carrier, there is the possibility that the position of the printhead will be rotationally erroneous. Such errors arise due to the tolerances in the assembly process, for example.

In cases where the printhead module is short, and particularly where it is the only module in the printhead, minor rotational errors may be acceptable. However, in the case of relatively long printheads, the amount of error introduced to dot positions due to the erroneous rotational position of the printhead module relative to the carrier may reach noticeable, and therefore unacceptable (or at least undesirable) levels.

The problem is exacerbated when multiple printhead modules are laid end to end to form a printhead, such as a pagewidth printhead, due to the fact that some fomis of rotational error will cause discontinuities between rows of dots printed by adjacent modules. In general, these discontinuities are more visible and objectionable than mere consistent skew across a single printhead module.

It would be useful to provide a method and apparatus for at least partially compensating for enrors in ink dot placement due to erroneous rotational displacement of a printhead module relative to a carrier.
SUMMARY OF THE INVENTION

In a first aspect the present invention provides a method of at least partially compensating for errors in ink dot placement by at least one of a plurality of nozzles due to erroneous rotational displacement of a printhead module relative to a carrier, the nozzles being disposed on the printhead module, the method comprising the steps of:

(a) deterrnining the rotational displacement;

(b) determining at least one correction factor that at least partially compensates for the ink dot displacement;
and

3 (c) using the correction factor to alter the output of the ink dots to at least partially compensate for the rotational displacement.

Optionally, step (c) includes altering a timing of a fire signal to at least one of the nozzles on the basis of the correction factor, thereby to effect the at least partial compensation.

Optionally, the nozzles are disposed in a plurality of rows, and step (c) includes reallocating at least one of the ink dots from at least one original print line to at least one alternate print line, thereby to effect the at least partial compensation.

Optionally, step (c) further includes the step of altering a timing of fire signals to at least one of the nozzles on the basis of the correction factor, thereby to effect the at least partial compensation.

Optionally, the altered fire signals are supplied to both reallocated ink dots and non-reallocated ink dots.

Optionally, the correction factor is stored in a memory associated with the printhead.

Optionally, the memory is mounted with the printhead, the printhead being mounted on the print engine.
Optionally, the rotational displacement is roll.

Optionally, the rotational displacement is yaw.

Optionally, the printhead module being one of a plurality of printhead modules mounted on a carrier to form a printhead and the error in ink dot placement being an error relative to ink dots output by one or more of the other printhead modules Optionally, the printer is a pagewidth printer.

4 Optionally, the printer is a pagewidth printer.

Optionally, the present invention provides a printer controller programmed and configured to implement the method of at least partially compensating for errors in ink dot placement by at least one of a plurality of nozzles due to erroneous rotational displacement of a printhead module relative to a carrier, the nozzles being disposed on the printhead module, the method comprising the steps of:

(a) determining the rotational displacement;

(b) determining at least one correction factor that at least partially compensates for the ink dot displacement;
and (c) using the correction factor to alter the output of the ink dots to at least partially compensate for the rotational displacement.

Optionally, the method including expelling ink from a printhead module including at least one row that comprises a plurality of adjacent sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, the method comprising providing, for each set of nozzles, a fire signal in accordance with the sequence: [nozzle position 1, nozzle position n, nozzle position 2, nozzle position (n-1), ... , nozzle position x], wherein nozzle position x is at or adjacent the centre of the set of nozzles.

Optionally, the method including expelling ink from a printhead module including at least one row that comprises a plurality of sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, the method comprising the steps of:

(a) providing a fire signal to nozzles at a first and nth position in each set of nozzles;
(b) providing a fire signal to the next inward pair of nozzles in each set;

(c) in the event n is an even number, repeating step (b) until all of the nozzles in each set has been fired; and (d) in the event n is an odd number, repeating step (b) until all of the nozzles but a central nozzle in each set have been fired, and then firing the central nozzle.

Optionally, the method including manufacturing a plurality of printhead modules, at least some of which are capable of being combined in pairs to form bilithic pagewidth printheads, the method comprising the step of laying out each of the plurality of printhead modules on a wafer substrate, wherein at least one of the printhead modules is right-handed and at least another is left-handed.

5 PCT/AU2004/000706 Optionally, the method being performed in conjunction with a printhead module including:

at least one row of print nozzles;

at least two shift registers for shifting in dot data supplied from a data source to each of the at least one rows, 5 wherein each print nozzle obtains dot data to be fired from an element of one of the shift registers.
Optionally, the method being performed in a printer comprising:

a printhead comprising at least a first elongate printhead module, the at least one printhead module including at least one row of print nozzles for expelling ink; and at least first and second printer controllers configured to receive print data and process the print data to output dot data to the printhead, wherein the first and second printer controllers are connected to a common input of the printhead.

Optionally, the method being performed in a printer comprising:

a printhead comprising first and second elongate printhead modules, the printhead modules being parallel to each other and being disposed end to end on either side of a join region;

at least first and second printer controllers configured to receive print data and process the print data to output dot data to the printhead, wherein the first printer controller outputs dot data only to the first printhead module and the second printer controller outputs dot data only to the second printhead module, wherein the printhead modules are configured such that no dot data passes between them.
Optionally, the method being performed in a printer comprising:

a printhead comprising first and second elongate printhead modules, the printhead modules being parallel to each other and being disposed end to end on either side of a join region, wherein the first printhead module is longer than the second printhead module;

at least first and second printer controllers configured to receive print data and process the print data to output dot data to the printhead, wherein: the first printer controller outputs dot data to both the first printhead module and the second printhead module; and the second printer controller outputs dot data only to the second printhead module.

Optionally, the method being performed in a printer comprising:

6 a printhead comprising first and second elongate printhead modules, the printhead modules being parallel to each other and being disposed end to end on either side of a join region, wherein the first printhead module is longer than the second printhead module;

at least first and second printer controllers configured to receive print data and process the print data to output dot data for the printhead, wherein: the first printer controller outputs dot data to both the first printhead module and the second controller; and the second printer controller outputs dot data to the second printhead module, wherein the dot data output by the second printer controller includes dot data it generates and at least some of the dot data received from the fust printer controller.

Optionally, the method being performed in conjunction with a printer controller for supplying dot data to at least one printhead module and at least partially compensating for errors in ink dot placement by at least one of a plurality of nozzles on the printhead module due to erroneous rotational displacement of the printhead module relative to a carrier, the printer being configured to:

access a correction factor associated with the at least one printhead module;

determine an order in which at least some of the dot data is supplied to at least one of the at least one printhead modules, the order being determined at least partly on the basis of the correction factor, thereby to at least partially compensate for the rotational displacement; and supply the dot data to the printhead module.

Optionally, the method being performed in conjunction with a printer controller for supplying dot data to a printhead module having a plurality of nozzles for expelling ink, the printhead module including a plurality of thermal sensors, each of the thermal sensors being configured to respond to a temperature at or adjacent at least one of the nozzles, the printer controller being configured to modify operation of at least some of the nozzles in response to the temperature rising above a first threshold.

Optionally, the method being performed in conjunction with a printer controller for controlling a printhead comprising at least one monolithic printhead module, the at least one printhead module having a plurality of rows of nozzles configured to extend, in use, across at least part of a printable pagewidth of the printhead, the nozzles in each row being grouped into at least first and second fire groups, the printhead module being configured to sequentially fire, for each row, the nozzles of each fire group, such that each nozzle in the sequence from each fire group is fired simultaneously with respective corresponding nozzles in the sequence in the other fire groups, wherein the nozzles are fired row by row such that the nozzles of each row are all fired before the nozzles of each

7 subsequent row, wherein the printer controller is configured to provide one or more control signals that control the order of firing of the nozzles.

Optionally, the method being performed in conjunction with a printer controller for outputting to a printhead module:

dot data to be printed with at least two different inks; and control data for controlling printing of the dot data;

the printer controller including at least one communication output, each or the communication output being configured to output at least some of the control data and at least some of the dot data for the at least two inks.

Optionally, the method being performed in conjunction with a printhead module including at least one row of printhead nozzles, at least one row including at least one displaced row portion, the displacement of the row portion including a component in a direction normal to that of a pagewidth to be printed.

Optionally, the method being performed in conjunction with a printer controller for supplying print data to at least one printhead module capable of printing a maximum of n of channels of print data, the at least one printhead module being configurable into:

a first mode, in which the printhead module is configured to receive data for a first number of the channels; and a second mode, in which the printhead module is configured to receive print data for a second number of the channels, wherein the first number is greater than the second number;

wherein the printer controller is selectively configurable to supply dot data for the first and second modes.

Optionally, the method being performed in conjunction with a printer controller for supplying data to a printhead comprising a plurality of printhead modules, the printhead being wider than a reticle step used in forming the modules, the printhead comprising at least two types of the modules, wherein each type is determined by its geometric shape in plan.

8 Optionally, the method being used in conjunction with a printer controller for supplying one or more control signals to a printhead module, the printhead module including at least one row that comprises a plurality of sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, such that:

(a) providing a fire signal to nozzles at a first and nth position in each set of nozzles;
(b) providing a fire signal to the next inward pair of nozzles in each set;

(c) in the event n is an even number, repeating step (b) until all of the nozzles in each set has been fired; and (d) in the event n is an odd number, repeating step (b) until all of the nozzles but a central nozzle in each set have been fired, and then firing the central nozzle.

Optionally, the method being used in conjunction with a printer controller for supplying one or more control signals to a printhead module, the printhead module including at least one row that comprises a plurality of adjacent sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, the method comprising providing, for each set of nozzles, a fire signal in accordance with the sequence: [nozzle position 1, nozzle position n, nozzle position 2, nozzle position (n-1), ... , nozzle position x], wherein nozzle position x is at or adjacent the centre of the set of nozzles.

Optionally, the method being performed in conjunction with a printer controller for supplying dot data to a printhead module comprising at least first and second rows configured to print ink of a similar type or color, at least some nozzles in the first row being aligned with respective corresponding nozzles in the second row in a direction of intended media travel relative to the printhead, the printhead module being configurable such that the nozzles in the fust and second pairs of rows are fired such that some dots output to print media are printed to by nozzles from the first pair of rows and at least some other dots output to print media are printed to by nozzles from the second pair of rows, the printer controller being configurable to supply dot data to the printhead module for printing.

Optionally, the method being performed in conjunction with a printer controller for supplying dot data to at least one printhead module, the at least one printhead module comprising a plurality of rows, each of the rows comprising a plurality of nozzles for ejecting ink, wherein the printhead module includes at least first and second rows configured to print ink of a similar type or color, the printer controller being configured to supply the dot data to the at least one printhead module such that, in the event a nozzle in the first row is faulty, a corresponding nozzle in the second row prints an ink dot at a position on print media at or adjacent a position where the faulty nozzle would otherwise have printed it.

9 Optionally, the method being perfonned in conjunction with a printer controller for receiving first data and manipulating the first data to produce dot data to be printed, the print controller including at least two serial outputs for supplying the dot data to at least one printhead, wherein each of the serial outputs is configured to supply dot data for at least two channels of the at least one printhead.

Optionally, the method being performed in conjunctioin with a printhead module including:
at least one row of print nozzles;

at least first and second shift registers for shifting in dot data supplied from a data source, wherein each shift register feeds dot data to a group of nozzles, and wherein each of the groups of the nozzles is interleaved with at least one of the other groups of the nozzles.

Optionally, the method being performed in conjunction with a printhead capable of printing a maximum of n of channels of print data, the printhead being configurable into:

a first mode, in which the printhead is configured to receive print data for a first number of the channels;
and a second mode, in which the printhead is configured to receive print data for a second number of the channels, wherein the first number is greater than the second number.

Optionally, the method being performed in conjunction with a printhead comprising a plurality of printhead modules, the printhead being wider than a reticle step used in fornung the modules, the printhead comprising at least two types of the modules, wherein each type is determined by its geometric shape in plan.

Optionally, the method being performed in conjunction with a printhead module including at least one row that comprises a plurality of sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, such that, for each set of nozzles, a fire signal is provided in accordance with the sequence: [nozzle position 1, nozzle position n, nozzle position 2, nozzle position (n-1), ... , nozzle position x], wherein nozzle position x is at or adjacent the centre of the set of nozzles.

Optionally, the method being performed in conjunction with a printhead module including at least one row that comprises a plurality of adjacent sets of n adjacent nozzles, each of the nozzles being configured to expel the ink in response to a fire signal, the printhead being configured to output ink from nozzles at a first and nth position in each set of nozzles, and then each next inward pair of nozzles in each set, until:

in the event n is an even number, all of the nozzles in each set has been fired; and in the event n is an odd number, all of the nozzles but a central nozzle in each set have been fired, and then to fire the central nozzle.

5 Optionally, the method being performed in conjunction with a printhead module for receiving dot data to be printed using at least two different inks and control data for controlling printing of the dot data, the printhead module including a communication input for receiving the dot data for the at least two colors and the control data.
Optionally, the method being performed in conjunction with a printhead module including at least one row of

10 printhead nozzles, at least one row including at least one displaced row portion, the displacement of the row portion including a component in a direction normal to that of a pagewidth to be printed.

Optionally, the method being performed in conjunction with a printhead module having a plurality of rows of nozzles configured to extend, in use, across at least part of a printable pagewidth, the nozzles in each row being grouped into at least first and second fire groups, the printhead module being configured to sequentially fire, for each row, the nozzles of each fire group, such that each nozzle in the sequence from each fire group is fired simultaneously with respective corresponding nozzles in the sequence in the other fire groups, wherein the nozzles are fired row by row such that the nozzles of each row are all fired before the nozzles of each subsequent row.

Optionally, the met hod being performed in conjunction with a printhead module comprising at least first and second rows configured to print ink of a similar type or color, at least some nozzles in the first row being aligned with respective corresponding nozzles in the second row in a direction of intended media travel relative to the printhead, the printhead module being configurable such that the nozzles in the first and second pairs of rows are fired such that some dots output to print media are printed to by nozzles from the first pair of rows and at least some other dots output to print media are printed to by nozzles from the second pair of rows.

Optionally, the method being performed in conjunction with a printer controller for providing data to a printhead module that includes:

at least one row of print nozzles;

at least first and second shift registers for shifting in dot data supplied from a data source, wherein each shift register feeds dot data to a group of nozzles, and wherein each of the groups of the nozzles is interleaved with at least one of the other groups of the nozzles.

11 Optionally, the method being performed in conjunction with a printhead module having a plurality of nozzles for expelling ink, the printhead module including a plurality of thermal sensors, each of the thermal sensors being configured to respond to a temperature at or adjacent at least one of the nozzles, the printhead module being configured to modify operation of the nozzles in response to the temperature rising above a first threshold.
Optionally, the method being performed in conjunction with a printhead module comprising a plurality of rows, each of the rows comprising a plurality of nozzles for ejecting ink, wherein the printhead module includes at least first and second rows configured to print ink of a siniilar type or color, and being configured such that, in the event a nozzle in the first row is faulty, a corresponding nozzle in the second row prints an ink dot at a position on print media at or adjacent a position where the faulty nozzle would otherwise have printed it.

In a second aspect the present invention provides a method of expelling ink from a printhead module including at least one row that comprises a plurality of adjacent sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, the method comprising providing, for each set of nozzles, a fire signal in accordance with the sequence: [nozzle position 1, nozzle position n, nozzle position 2, nozzle position (n-1), ... , nozzle position x], wherein nozzle position x is at or adjacent the centre of the set of nozzles.
Optionally the nozzle at each given position within the set is fired simultaneously with the nozzles in the other sets at respective corresponding positions.

Optionally the printhead module includes a plurality of the rows of nozzles, the method including sequentially repeating the for each of the rows of nozzles.

Optionally the rows are disposed in pairs.

Optionally the rows in each pair of rows are offset relative to each other.
Optionally each pair of rows is configured to print the same color ink.

Optionally each pair of rows is connected to a common ink source.

12 Optionally the sets of nozzles are adjacent each other.

Optionally the sets of nozzles are separated by an intermediate nozzle, the intermediate nozzle being fired either prior to the nozzle at position 1 in each set, or following the nozzle at position n.

Optionally the method includes the step of providing the fire sequence to the printhead module from a printer controller, the fire signals being based on the fire sequence.

Optionally the fire sequence is loaded into a shift register in the printhead module.

Optionally the method at least partially compensating for errors in ink dot placement by at least one of a plurality of nozzles due to erroneous rotational displacement of a printhead module relative to a carrier, the nozzles being disposed on the printhead module, the method comprising the steps of:

(a) determining the rotational displacement;

(b) determining at least one correction factor that at least partially compensates for the ink dot displacement;
and (c) using the correction factor to alter the output of the ink dots to at least partially compensate for the rotational displacement.

Optionally the method includes expelling ink from a printhead module including at least one row that comprises a plurality of sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, the method comprising the steps of:

(a) providing a fire signal to nozzles at a first and nth position in each set of nozzles;
(b) providing a fire signal to the next inward pair of nozzles in each set;

(c) in the event n is an even number, repeating step (b) until all of the nozzles in each set has been fired; and (d) in the event n is an odd number, repeating step (b) until all of the nozzles but a central nozzle in each set have been fired, and then firing the central nozzle.

13 Optionally the method includes manufacturing a plurality of printhead modules, at least some of which are capable of being combined in pairs to form bilithic pagewidth printheads, the method comprising the step of laying out each of the plurality of printhead modules on a wafer substrate, wherein at least one of the printhead modules is right-handed and at least another is left-handed.

Optionally, the method being performed in conjunction with a printhead module including:
at least one row of print nozzles;

at least two shift registers for shifting in dot data supplied from a data source to each of the at least one rows, wherein each print nozzle obtains dot data to be fired from an element of one of the shift registers.

Optionally, the method being performed in a printer comprising:

a printhead comprising at least a first elongate printhead module, the at least one printhead module including at least one row of print nozzles for expelling ink; and at least first and second printer controllers configured to receive piint data and process the print data to output dot data to the printhead, wherein the first and second printer controllers are connected to a common input of the printhead.

Optionally, the method being performed in a printer comprising:

a printhead comprising first and second elongate printhead modules, the printhead modules being parallel to each other and being disposed end to end on either side of a join region;

at least first and second printer controllers configured to receive print data and process the print data to output dot data to the printhead, wherein the first printer controller outputs dot data only to the first printhead module and the second printer controller outputs dot data only to the second printhead module, wherein the printhead modules are configured such that no dot data passes between them.

Optionally, the method being performed in a printer comprising:

a printhead comprising first and second elongate printhead modules, the printhead modules being parallel to each other and being disposed end to end on either side of a join region, wherein the first printhead module is longer than the second printhead module;

at least first and second printer controllers configured to receive print data and process the print data to output dot data to the printhead, wherein: the first printer controller outputs dot data to both the first printhead

14 module and the second printhead module; and the second printer controller outputs dot data only to the second printhead module.

Optionally, the method being performed in a printer comprising:

a printhead comprising first and second elongate printhead modules, the printhead modules being parallel to each other and being disposed end to end on either side of a join region, wherein the first printhead module is longer than the second printhead module;

at least first and second printer controllers configured to receive print data and process the print data to output dot data for the printhead, wherein: the first printer controller outputs dot data to both the first printhead module and the second controller; and the second printer controller outputs dot data to the second printhead module, wherein the dot data output by the second printer controller includes dot data it generates and at least some of the dot data received from the fust printer controller.

Optionally, the method being performed in conjunction with a printer controller for supplying dot data to at least one printhead module and at least partially compensating for errors in ink dot placement by at least one of a plurality of nozzles on the printhead module due to erroneous rotational displacement of the printhead module relative to a carrier, the printer being configured to:

access a correction factor associated with the at least one printhead module;

determine an order in which at least some of the dot data is supplied to at least one of the at least one printhead modules, the order being determined at least partly on the basis of the correction factor, thereby to at least partially compensate for the rotational displacement; and supply the dot data to the printhead module.

Optionally, the method being performed in conjunction with a printer controller for supplying dot data to a printhead module having a plurality of nozzles for expelling ink, the printhead module including a plurality of thermal sensors, each of the thermal sensors being configured to respond to a temperature at or adjacent at least one of the nozzles, the printer controller being configured to modify operation of at least some of the nozzles in response to the temperature rising above a first threshold.

Optionally, the method being performed in conjunction with a printer controller for controlling a printhead comprising at least one monolithic printhead module, the at least one printhead module having a plurality of rows of nozzles configured to extend, in use, across at least part of a printable pagewidth of the printhead, the nozzles in each row being grouped into at least first and second fire groups, the printhead module being configured to sequentially fire, for each row, the nozzles of each fire group, such that each nozzle in the sequence from each fire group is fired simultaneously with respective corresponding nozzles in the sequence in the other fire groups, wherein the nozzles are fired row by row such that the nozzles of each row are all fired before the nozzles of each 5 subsequent row, wherein the printer controller is configured to provide one or more control signals that control the order of firing of the nozzles.

Optionally, the method being performed in conjunction with a printer controller for outputting to a printhead module:

10 dot data to be printed with at least two different inks; and control data for controlling printing of the dot data;

the printer controller including at least one communication output, each or the communication output being configured to output at least some of the control data and at least some of the dot data for the at least two inks.

Optionally, the method being performed in conjunction with a printhead module including at least one row of printhead nozzles, at least one row including at least one displaced row portion, the displacement of the row portion including a component in a direction normal to that of a pagewidth to be printed.

Optionally, the method being performed in conjunction with a printer controller for supplying print data to at least one printhead module capable of printing a maximum of n of channels of print data, the at least one printhead module being configurable into:

a first mode, in which the printhead module is configured to receive data for a first number of the channels; and a second mode, in which the printhead module is configured to receive print data for a second number of the channels, wherein the first number is greater than the second number;

wherein the printer controller is selectively configurable to supply dot data for the first and second modes.
Optionally, the method being performed in conjunction with a printer controller for supplying data to a printhead comprising a plurality of printhead modules, the printhead being wider than a reticle step used in forming the modules, the printhead comprising at least two types of the modules, wherein each type is determined by its geometric shape in plan.

Optionally, the method being used in conjunction with a printer controller for supplying one or more control signals to a printhead module, the printhead module including at least one row that comprises a plurality of sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, such that:

(a) providing a fire signal to nozzles at a first and nth position in each set of nozzles;
(b) providing a fire signal to the next inward pair of nozzles in each set;

(c) in the event n is an even number, repeating step (b) until all of the nozzles in each set has been fired; and (d) in the event n is an odd number, repeating step (b) until all of the nozzles but a central nozzle in each set have been fired, and then firing the central nozzle.

Optionally, the method being used in conjunction with a printer controller for supplying one or more control signals to a printhead module, the printhead module including at least one row that comprises a plurality of adjacent sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, the method comprising providing, for each set of nozzles, a fire signal in accordance with the sequence: [nozzle position 1, nozzle position n, nozzle position 2, nozzle position (n-1), ... , nozzle position x], wherein nozzle position x is at or adjacent the centre of the set of nozzles.

Optionally, the method being performed in conjunction with a printer controller for supplying dot data to a printhead module comprising at least first and second rows configured to print ink of a similar type or color, at least some nozzles in the first row being aligned with respective corresponding nozzles in the second row in a direction of intended media travel relative to the printhead, the printhead module being configurable such that the nozzles in the first and second pairs of rows are fired such that some dots output to print media are printed to by nozzles from the first pair of rows and at least some other dots output to print media are printed to by nozzles from the second pair of rows, the printer controller being configurable to supply dot data to the printhead module for printing.

Optionally, the method being performed in conjunction with a printer controller for supplying dot data to at least one printhead module, the at least one printhead module comprising a plurality of rows, each of the rows comprising a plurality of nozzles for ejecting ink, wherein the printhead module includes at least first and second rows configured to print ink of a similar type or color, the printer controller being configured to supply the dot data to the at least one printhead module such that, in the event a nozzle in the first row is faulty, a corresponding nozzle in the second row prints an ink dot at a position on print media at or adjacent a position where the faulty nozzle would otherwise have printed it.

Optionally, the method being performed in conjunction with a printer controller for receiving first data and manipulating the first data to produce dot data to be printed, the print controller including at least two serial outputs for supplying the dot data to at least one printhead, wherein each of the serial outputs is configured to supply dot data for at least two channels of the at least one printhead.

Optionally, the method being performed in conjunction with a printhead module including:
at least one row of print nozzles;

at least first and second shift registers for shifting in dot data supplied from a data source, wherein each shift register feeds dot data to a group of nozzles, and wherein each of the groups of the nozzles is interleaved with at least one of the other groups of the nozzles.

Optionally, the method being performed in conjunction with a printhead capable of printing a maximum of n of channels of print data, the printhead being configurable into:

a fust mode, in which the printhead is configured to receive print data for a first number of the channels;
and a second mode, in which the printhead is configured to receive print data for a second number of the channels, wherein the first number is greater than the second number.

Optionally, the method being performed in conjunction with a printhead comprising a plurality of printhead modules, the printhead being wider than a reticle step used in forming the modules, the printhead comprising at least two types of the modules, wherein each type is determined by its geometric shape in plan.

Optionally, the method being performed in conjunction with a printhead module including at least one row that comprises a plurality of sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, such that, for each set of nozzles, a fire signal is provided in accordance with the sequence: [nozzle position 1, nozzle position n, nozzle position 2, nozzle position (n-1), ... , nozzle position x], wherein nozzle position x is at or adjacent the centre of the set of nozzles.

Optionally, the method being perfonned in conjunction with a printhead module including at least one row that comprises a plurality of adjacent sets of n adjacent nozzles, each of the nozzles being configured to expel the ink in response to a fire signal, the printhead being configured to output ink from nozzles at a first and nth position in each set of nozzles, and then each next inward pair of nozzles in each set, until:

in the event n is an even number, all of the nozzles in each set has been fired; and in the event n is an odd number, all of the nozzles but a central nozzle in each set have been fired, and then to fire the central nozzle.

Optionally, the method being performed in conjunction with a printhead module for receiving dot data to be printed using at least two different inks and control data for controlling printing of the dot data, the printhead module including a communication input for receiving the dot data for the at least two colors and the control data.

Optionally, the method being performed in conjunction with a printhead module including at least one row of printhead nozzles, at least one row including at least one displaced row portion, the displacement of the row portion including a component in a direction normal to that of a pagewidth to be printed.

Optionally, the method being performed in conjunction with a printhead module having a plurality of rows of nozzles configured to extend, in use, across at least part of a printable pagewidth, the nozzles in each row being grouped into at least first and second fire groups, the printhead module being configured to sequentially fire, for each row, the nozzles of each fire group, such that each nozzle in the sequence from each fire group is fired simultaneously with respective corresponding nozzles in the sequence in the other fire groups, wherein the nozzles are fired row by row such that the nozzles of each row are all fired before the nozzles of each subsequent row.
Optionally, the method being performed in conjunction with a printhead module comprising at least first and second rows configured to print ink of a similar type or color, at least some nozzles in the first row being aligned with respective corresponding nozzles in the second row in a direction of intended media travel relative to the printhead, the printhead module being configurable such that the nozzles in the first and second pairs of rows are fired such that some dots output to print media are printed to by nozzles from the first pair of rows and at least some other dots output to print media are printed to by nozzles from the second pair of rows.

Optionally, the method being performed in conjunction with a printer controller for providing data to a printhead module that includes:

at least one row of pcint nozzles;

at least first and second shift registers for shifting in dot data supplied from a data source, wherein each shift register feeds dot data to a group of nozzles, and wherein each of the groups of the nozzles is interleaved with at least one of the other groups of the nozzles.

Optionally, the method being performed in conjunction with a printhead module having a plurality of nozzles for expelling ink, the printhead module including a plurality of thermal sensors, each of the thermal sensors being configured to respond to a temperature at or adjacent at least one of the nozzles, the printhead module being configured to modify operation of the nozzles in response to the temperature rising above a first threshold.

Optionally, the method being performed in conjunction with a printhead module comprising a plurality of rows, each of the rows comprising a plurality of nozzles for ejecting ink, wherein the printhead module includes at least first and second rows configured to print ink of a similar type or color, and being configured such that, in the event a nozzle in the first row is faulty, a corresponding nozzle in the second row prints an ink dot at a position on print media at or adjacent a position where the faulty nozzle would otherwise have printed it.

Optionally the printhead module includes a plurality of the rows, the method including firing each nozzle in each row simultaneously with the nozzle or nozzles at the same position in the other rows.

Optionally the method includes a plurality of pairs of the rows, each pair of rows including an odd row and an even row, the odd and even rows in each pair being offset from each other in both x and y directions relative to an intended direction of print media movement relative to the printhead, the method including causing firing of at least a plurality of the odd rows prior to firing any of the even rows, or vice versa.

Optionally all the odd rows are fired before any of the even rows are fired, or vice versa.

Optionally the odd rows, or the even rows, or both, are fired in a predetennined order.

Optionally the predetermined order is selectable from a plurality of predetermined available orders.
Optionally the predetermined order is sequential.

Optionally the predetermined order can commence at any of a plurality of the rows.

In a third aspect the present invention provides a method of expelling ink from a printhead module including at least one row that comprises a plurality of sets of n adjacent nozzles, each of the nozzles being configured to expel 5 ink in response to a fire signal, the method comprising the steps of:

(a) providing a fire signal to nozzles at a first and nth position in each set of nozzles;
(b) providing a fire signal to the next inward pair of nozzles in each set;

(c) in the event n is an even number, repeating step (b) until all of the nozzles in each set has been fired; and (d) in the event n is an odd number, repeating step (b) until all of the nozzles but a central nozzle in each set 10 have been fired, and then firing the central nozzle.

Optionally the printhead module includes a plurality of the rows of nozzles, the method including sequentially repeating steps (a) to (d) for each of the rows of nozzles.

15 Optionally the rows are disposed in pairs.

Optionally the rows in each pair of rows are offset relative to each other.
Optionally each pair of rows is configured to print the same color ink.

Optionally each pair of rows is connected to a common ink source.
Optionally the sets of nozzles are adjacent each other.

Optionally the sets of nozzles are separated by an intermediate nozzle, the intermediate nozzle being fired either prior to the nozzle at position 1 in each set, or following the nozzle at position n.

In a second aspect the present invention provides a method of expelling ink from a printhead module including at least one row that comprises a plurality of adjacent sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, the method comprising providing, for each set of nozzles, a fire signal in accordance with the sequence: [nozzle position 1, nozzle position n, nozzle position 2, nozzle position (n-1), ... , nozzle position x], wherein nozzle position x is at or adjacent the centre of the set of nozzles.

Optionally the nozzle at each given position within the set is fired simultaneously with the nozzles in the other sets at respective corresponding positions.

Optionally, the method at least partially compensating for errors in ink dot placement by at least one of a plurality of nozzles due to erroneous rotational displacement of a printhead module relative to a carrier, the nozzles being disposed on the printhead module, the method comprising the steps of:

(a) determining the rotational displacement;

(b) determining at least one correction factor that at least partially compensates for the ink dot displacement;
and (c) using the correction factor to alter the output of the ink dots to at least partially compensate for the rotational displacement.

Optionally, the method including expelling ink from a printhead module including at least one row that comprises a plurality of adjacent sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, the method comprising providing, for each set of nozzles, a fire signal in accordance with the sequence: [nozzle position 1, nozzle position n, nozzle position 2, nozzle position (n-1), ... , nozzle position x], wherein nozzle position x is at or adjacent the centre of the set of nozzles.

Optionally, the method including manufacturing a plurality of printhead modules, at least some of which are capable of being combined in pairs to form bilithic pagewidth printheads, the method comprising the step of laying out each of the plurality of printhead modules on a wafer substrate, wherein at least one of the printhead modules is right-handed and at least another is left-handed.

Optionally, the method being performed in conjunction with a printhead module including:
at least one row of print nozzles;

at least two shift registers for shifting in dot data supplied from a data source to each of the at least one rows, wherein each print nozzle obtains dot data to be fired from an element of one of the shift registers.

Optionally, the method being performed in a printer comprising:

a printhead comprising at least a first elongate printhead module, the at least one printhead module including at least one row of print nozzles for expelling ink; and at least first and second printer controllers configured to receive print data and process the print data to output dot data to the printhead, wherein the first and second printer controllers are connected to a common input of the printhead.

Optionally, the method being performed in a printer comprising:

a printhead comprising first and second elongate printhead modules, the printhead modules being parallel to each other and being disposed end to end on either side of a join region;

at least first and second printer controllers configured to receive print data and process the print data to output dot data to the printhead, wherein the first printer controller outputs dot data only to the first printhead module and the second printer controller outputs dot data only to the second printhead module, wherein the printhead modules are configured such that no dot data passes between them.
Optionally, the method being performed in a printer comprising:

a printhead comprising first and second elongate printhead modules, the printhead modules being parallel to each other and being disposed end to end on either side of a join region, wherein the first printhead module is longer than the second printhead module;

at least first and second printer controllers configured to receive print data and process the print data to output dot data to the printhead, wherein: the first printer controller outputs dot data to both the first printhead module and the second printhead module; and the second printer controller outputs dot data only to the second printhead module.

Optionally, the method being performed in a printer comprising:

a printhead comprising first and second elongate printhead modules, the printhead modules being parallel to each other and being disposed end to end on either side of a join region, wherein the first printhead module is longer than the second printhead module;

at least first and second printer controllers configured to receive print data and process the print data to output dot data for the printhead, wherein: the first printer controller outputs dot data to both the first printhead module and the second controller; and the second printer controller outputs dot data to the second printhead module, wherein the dot data output by the second printer controller includes dot data it generates and at least some of the dot data received from the fust printer controller.

Optionally, the method being performed in conjunction with a printer controller for supplying dot data to at least one printhead module and at least partially compensating for errors in ink dot placement by at least one of a plurality of nozzles on the printhead module due to erroneous rotational displacement of the printhead module relative to a carrier, the printer being configured to:

access a correction factor associated with the at least one printhead module;

deterniine an order in which at least some of the dot data is supplied to at least one of the at least one printhead modules, the order being determined at least partly on the basis of the correction factor, thereby to at least partially compensate for the rotational displacement; and supply the dot data to the printhead module.

Optionally, the method being performed in conjunction with a printer controller for supplying dot data to a printhead module having a plurality of nozzles for expelling ink, the printhead module including a plurality of thermal sensors, each of the thermal sensors being configured to respond to a temperature at or adjacent at least one of the nozzles, the printer controller being configured to modify operation of at least some of the nozzles in response to the temperature rising above a first threshold.

Optionally, the method being performed in conjunction with a printer controller for controlling a printhead comprising at least one monolithic printhead module, the at least one printhead module having a plurality of rows of nozzles configured to extend, in use, across at least part of a printable pagewidth of the printhead, the nozzles in each row being grouped into at least first and second fire groups, the printhead module being configured to sequentially fire, for each row, the nozzles of each fire group, such that each nozzle in the sequence from each fire group is fired simultaneously with respective corresponding nozzles in the sequence in the other fire groups, wherein the nozzles are fired row by row such that the nozzles of each row are all fired before the nozzles of each subsequent row, wherein the printer controller is configured to provide one or more control signals that control the order of firing of the nozzles.

Optionally, the method being performed in conjunction with a printer controller for outputting to a printhead module:

dot data to be printed with at least two different inks; and control data for controlling printing of the dot data;

the printer controller including at least one communication output, each or the communication output being configured to output at least some of the control data and at least some of the dot data for the at least two inks.

Optionally, the method being performed in conjunction with a printhead module including at least one row of printhead nozzles, at least one row including at least one displaced row portion, the displacement of the row portion including a component in a direction normal to that of a pagewidth to be printed.

Optionally, the method being performed in conjunction with a printer controller for supplying print data to at least one printhead module capable of printing a maximum of n of channels of print data, the at least one printhead module being configurable into:

a first mode, in which the printhead module is configured to receive data for a fust number of the channels; and a second mode, in which the printhead module is configured to receive print data for a second number of the channels, wherein the first number is greater than the second number;

wherein the printer controller is selectively configurable to supply dot data for the first and second modes.
Optionally, the method being performed in conjunction with a printer controller for supplying data to a printhead comprising a plurality of printhead modules, the printhead being wider than a reticle step used in forming the modules, the printhead comprising at least two types of the modules, wherein each type is determined by its geometric shape in plan.

Optionally, the method being used in conjunction with a printer controller for supplying one or more control signals to a printhead module, the printhead module including at least one row that comprises a plurality of sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, such that:

(a) providing a fire signal to nozzles at a first and nth position in each set of nozzles;
(b) providing a fire signal to the next inward pair of nozzles in each set;

(c) in the event n is an even number, repeating step (b) until all of the nozzles in each set has been fired; and (d) in the event n is an odd number, repeating step (b) until all of the nozzles but a central nozzle in each set have been fired, and then firing the central nozzle.

Optionally, the method being used in conjunction with a printer controller for supplying one or more control signals to a printhead module, the printhead module including at least one row that comprises a plurality of adjacent sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, 5 the method comprising providing, for each set of nozzles, a fire signal in accordance with the sequence: [nozzle position 1, nozzle position n, nozzle position 2, nozzle position (n-1), ... , nozzle position x], wherein nozzle position x is at or adjacent the centre of the set of nozzles.

Optionally, the method being performed in conjunction with a printer controller for supplying dot data to a 10 printhead module comprising at least fust and second rows configured to print ink of a similar type or color, at least some nozzles in the fust row being aligned with respective corresponding nozzles in the second row in a direction of intended media travel relative to the printhead, the printhead module being configurable such that the nozzles in the first and second pairs of rows are fired such that some dots output to print media are printed to by nozzles from the first pair of rows and at least some other dots output to print media are printed to by nozzles from 15 the second pair of rows, the printer controller being configurable to supply dot data to the printhead module for printing.

Optionally, the method being performed in conjunction with a printer controller for supplying dot data to at least one printhead module, the at least one printhead module comprising a plurality of rows, each of the rows 20 comprising a plurality of nozzles for ejecting ink, wherein the printhead module includes at least first and second rows configured to print ink of a similar type or color, the printer controller being configured to supply the dot data to the at least one printhead module such that, in the event a nozzle in the first row is faulty, a corresponding nozzle in the second row prints an ink dot at a position on print media at or adjacent a position where the faulty nozzle would otherwise have printed it.

Optionally, the method being perfonned in conjunction with a printer controller for receiving first data and manipulating the first data to produce dot data to be printed, the print controller including at least two serial outputs for supplying the dot data to at least one printhead, wherein each of the serial outputs is configured to supply dot data for at least two channels of the at least one printhead.

Optionally, the method being performed in conjunction with a printhead module including:
at least one row of print nozzles;

at least first and second shift registers for shifting in dot data supplied from a data source, wherein each shift register feeds dot data to a group of nozzles, and wherein each of the groups of the nozzles is interleaved with at least one of the other groups of the nozzles.

Optionally, the method being performed in conjunction with a printhead capable of printing a maximum of n of channels of print data, the printhead being configurable into:

a first mode, in which the printhead is configured to receive print data for a first number of the channels;
and a second mode, in which the printhead is configured to receive print data for a second number of the channels, wherein the first number is greater than the second number.

Optionally, the method being performed in conjunction with a printhead comprising a plurality of printhead modules, the printhead being wider than a reticle step used in forming the modules, the printhead comprising at least two types of the modules, wherein each type is determined by its geometric shape in plan.

Optionally, the method being performed in conjunction with a printhead module including at least one row that comprises a plurality of sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, such that, for each set of nozzles, a fire signal is provided in accordance with the sequence: [nozzle position 1, nozzle position n, nozzle position 2, nozzle position (n-1), ... , nozzle position x], wherein nozzle position x is at or adjacent the centre of the set of nozzles.

Optionally, the method being performed in conjunction with a printhead module including at least one row that comprises a plurality of adjacent sets of n adjacent nozzles, each of the nozzles being configured to expel the ink in response to a fire signal, the printhead being configured to output ink from nozzles at a first and nth position in each set of nozzles, and then each next inward pair of nozzles in each set, until:

in the event n is an even number, all of the nozzles in each set has been fired; and in the event n is an odd number, all of the nozzles but a central nozzle in each set have been fired, and then to fire the central nozzle.

Optionally, the method being performed in conjunction with a printhead module for receiving dot data to be printed using at least two different inks and control data for controlling printing of the dot data, the printhead module including a communication input for receiving the dot data for the at least two colors and the control data.

Optionally, the method being performed in conjunction with a printhead module including at least one row of printhead nozzles, at least one row including at least one displaced row portion, the displacement of the row portion including a component in a direction normal to that of a pagewidth to be printed.

Optionally, the method being performed in conjunction with a printhead module having a plurality of rows of nozzles configured to extend, in use, across at least part of a printable pagewidth, the nozzles in each row being grouped into at least first and second fire groups, the printhead module being configured to sequentially fire, for each row, the nozzles of each fire group, such that each nozzle in the sequence from each fire group is fired simultaneously with respective corresponding nozzles in the sequence in the other fire groups, wherein the nozzles are fired row by row such that the nozzles of each row are all fired before the nozzles of each subsequent row.
Optionally, the method being perfonned in conjunction with a printhead module comprising at least first and second rows configured to print ink of a similar type or color, at least some nozzles in the first row being aligned with respective corresponding nozzles in the second row in a direction of intended media travel relative to the printhead, the printhead module being configurable such that the nozzles in the first and second pairs of rows are fired such that some dots output to print media are printed to by nozzles from the first pair of rows arid at least some other dots output to print media are printed to by nozzles from the second pair of rows.

Optionally, the method being performed in conjunction with a printer controller for providing data to a printhead module that includes:

at least one row of print nozzles;

at least first and second shift registers for shifting in dot data supplied from a data source, wherein each shift register feeds dot data to a group of nozzles, and wherein each of the groups of the nozzles is interleaved with at least one of the other groups of the nozzles.

Optionally, the method being performed in conjunction with a printhead module having a plurality of nozzles for expelling ink, the printhead module including a plurality of thermal sensors, each of the thermal sensors being configured to respond to a temperature at or adjacent at least one of the nozzles, the printhead module being configured to modify operation of the nozzles in response to the temperature rising above a first threshold.

Optionally, the method being performed in conjunction with a printhead module comprising a plurality of rows, each of the rows comprising a plurality of nozzles for ejecting ink, wherein the printhead module includes at least first and second rows configured to print ink of a similar type or color, and being configured such that, in the event a nozzle in the first row is faulty, a corresponding nozzle in the second row prints an ink dot at a position on print media at or adjacent a position where the faulty nozzle would otherwise have printed it.

Optionally the printhead module includes a plurality of the rows, the method including firing each nozzle in each row simultaneously with the nozzle or nozzles at the same position in the other rows.

Optionally the piinthead module includes a plurality of the rows, the method including firing each nozzle in each row simultaneously with the nozzle or nozzles at the same position in the other rows.

Optionally the method including a plurality of pairs of the rows, each pair of rows including an odd row and an even row, the odd and even rows in each pair being offset from each other in both x and y directions relative to an intended direction of print media movement relative to the printhead, the method including causing firing of at least a plurality of the odd rows prior to firing any of the even rows, or vice versa.
Optionally all the odd rows are fired before any of the even rows are fired, or vice versa.
Optionally the odd rows, or the even rows, or both, are fired in a predetermined order.

Optionally the predetermined order is selectable from a plurality of predetermined available orders.
Optionally the predetermined order is sequential.

Optionally the predetermined order can commence at any of a plurality of the rows.

In a fourth aspect the present invention provides method of manufacturing a plurality of printhead modules, at least some of which are capable of being combined in pairs to form bilithic pagewidth printheads, the method comprising the step of laying out each of the plurality of printhead modules on a wafer substrate, wherein at least one of the printhead modules is right-handed and at least another is left-handed.

In a second aspect the present invention provides a method of manufacturing a plurality of pagewidth printheads, the method comprising the steps of:

manufacturing a plurality of printhead modules in accordance with claim 1; and assembling pairs of at least some of the printhead modules to form pagewidth printheads, wherein each of the printhead modules in each pagewidth printhead is shorter than the pagewidth.

Optionally the printhead modules of at least one of the pagewidth printheads are of relatively different lengths.
Optionally the printhead modules of at least one of the pagewidth printheads are of the same length.
Optionally the printhead modules of at least one of the pagewidth printheads are of relatively different lengths, and the printhead modules of at least another of the pagewidth printheads are of the same length.

Optionally at least some of the printhead modules are larger than a reticle step used in laying out those printhead modules.

Optionally the method includes the step of laying out a plurality of left-handed and right-handed printhead modules.

Optionally the method includes the step of laying out a plurality of different lengths of left-handed and right-handed printhead modules.

Optionally, the method at least partially compensating for errors in ink dot placement by at least one of a plurality of nozzles due to erroneous rotational displacement of a printhead module relative to a carrier, the nozzles being disposed on the printhead module, the method comprising the steps of:

(a) determining the rotational displacement;

(b) determining at least one correction factor that at least partially compensates for the ink dot displacement;
and (c) using the correction factor to alter the output of the ink dots to at least partially compensate for the rotational displacement.

Optionally, the method including expelling ink from a printhead module including at least one row that comprises 5 a plurality of adjacent sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, the method comprising providing, for each set of nozzles, a fire signal in accordance with the sequence: [nozzle position 1, nozzle position n, nozzle position 2, nozzle position (n-1), ... , nozzle position x], wherein nozzle position x is at.or adjacent the centre of the set of nozzles.

10 Optionally, the method including expelling ink from a printhead module including at least one row that comprises a plurality of sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, the method comprising the steps of:

(a) providing a fire signal to nozzles at a first and nth position in each set of nozzles;
(b) providing a fire signal to the next inward pair of nozzles in each set;

15 (c) in the event n is an even number, repeating step (b) until all of the nozzles in each set has been fired; and (d) in the event n is an odd number, repeating step (b) until all of the nozzles but a central nozzle in each set have been fired, and then firing the central nozzle.

Optionally, the method being performed in conjunction with a printhead module including:
20 at least one row of print nozzles;

at least two shift registers for shifting in dot data supplied from a data source to each of the at least one rows, wherein each print nozzle obtains dot data to be fired from an element of one of the shift registers.
Optionally, the method being performed in a printer comprising:

25 a printhead comprising at least a first elongate printhead module, the at least one printhead module including at least one row of print nozzles for expelling ink; and at least first and second printer controllers configured to receive print data and process the print data to output dot data to the printhead, wherein the first and second printer controllers are connected to a common input of the printhead.

Optionally, the method being performed in a printer comprising:

a printhead comprising first and second elongate printhead modules, the printhead modules being parallel to each other and being disposed end to end on either side of a join region;

at least first and second printer controllers configured to receive print data and process the print data to output dot data to the printhead, wherein the first printer controller outputs dot data only to the first printhead module and the second printer controller outputs dot data only to the second printhead module, wherein the printhead modules are configured such that no dot data passes between them.

Optionally, the method being performed in a printer comprising:

a printhead comprising first and second elongate printhead modules, the printhead modules being parallel to each other and being disposed end to end on either side of a join region, wherein the first printhead module is longer than the second printhead module;

at least first and second printer controllers configured to receive print data and process the print data to output dot data to the printhead, wherein: the first printer controller outputs dot data to both the first printhead module and the second printhead module; and the second printer controller outputs dot data only to the second printhead module.

Optionally, the method being performed in a printer comprising:

a printhead comprising first and second elongate printhead modules, the printhead modules being parallel to each other and being disposed end to end on either side of a join region, wherein the first printhead module is longer than the second printhead module;

at least first and second printer controllers configured to receive print data and process the print data to output dot data for the printhead, wherein: the first printer controller outputs dot data to both the first printhead module and the second controller; and the second printer controller outputs dot data to the second printhead module, wherein the dot data output by the second printer controller includes dot data it generates and at least some of the dot data received from the first printer controller.

Optionally, the method being performed in conjunction with a printer controller for supplying dot data to at least one printhead module and at least partially compensating for errors in ink dot placement by at least one of a plurality of nozzles on the printhead module due to erroneous rotational displacement of the printhead module relative to a carrier, the printer being configured to:

access a correction factor associated with the at least one printhead module;

determine an order in which at least some of the dot data is supplied to at least one of the at least one printhead modules, the order being detennined at least partly on the basis of the correction factor, thereby to at least partially compensate for the rotational displacement; and supply the dot data to the printhead module.

Optionally, the method being performed in conjunction with a printer controller for supplying dot data to a printhead module having a plurality of nozzles for expelling ink, the printhead module including a plurality of thermal sensors, each of the thermal sensors being configured to respond to a temperature at or adjacent at least one of the nozzles, the printer controller being configured to modify operation of at least some of the nozzles in response to the temperature rising above a first threshold.

Optionally, the method being performed in conjunction with a printer controller for controlling a printhead comprising at least one monolithic printhead module, the at least one printhead module having a plurality of rows of nozzles configured to extend, in use, across at least part of a printable pagewidth of the printhead, the nozzles in each row being grouped into at least first and second fire groups, the printhead module being configured to sequentially fire, for each row, the nozzles of each fire group, such that each nozzle in the sequence from each fire group is fired simultaneously with respective corresponding nozzles in the sequence in the other fire groups, wherein the nozzles are fired row by row such that the nozzles of each row are all fired before the nozzles of each subsequent row, wherein the printer controller is configured to provide one or more control signals that control the order of firing of the nozzles.

Optionally, the method being performed in conjunction with a printer controller for outputting to a printhead module:

dot data to be printed with at least two different inks; and control data for controlling printing of the dot data;

the printer controller including at least one communication output, each or the communication output being configured to output at least some of the control data and at least some of the dot data for the at least two inks.
Optionally, the method being performed in conjunction with a printhead module including at least one row of printhead nozzles, at least one row including at least one displaced row portion, the displacement of the row portion including a component in a direction normal to that of a pagewidth to be printed.

Optionally, the method being performed in conjunction with a printer controller for supplying print data to at least one printhead module capable of printing a maximum of n of channels of print data, the at least one printhead module being configurable into:

a first mode, in which the printhead module is configured to receive data for a first number of the channels; and a second mode, in which the printhead module is configured to receive print data for a second number of the channels, wherein the first number is greater than the second number;

wherein the printer controller is selectively configurable to supply dot data for the first and second modes.

Optionally, the method being performed in conjunction with a printer controller for supplying data to a printhead comprising a plurality of printhead modules, the printhead being wider than a reticle step used in forming the modules, the printhead comprising at least two types of the modules, wherein each type is determined by its geometric shape in plan.

Optionally, the method being used in conjunction with a printer controller for supplying one or more control signals to a printhead module, the printhead module including at least one row that comprises a plurality of sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, such that:

(a) providing a fire signal to nozzles at a first and nth position in each set of nozzles;
(b) providing a fire signal to the next inward pair of nozzles in each set;

(c) in the event n is an even number, repeating step (b) until all of the nozzles in each set has been fired; and (d) in the event n is an odd number, repeating step (b) until all of the nozzles but a central nozzle in each set have been fired, and then firing the central nozzle.

Optionally, the method being used in conjunction with a printer controller for supplying one or more control signals to a printhead module, the printhead module including at least one row that comprises a plurality of adjacent sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, the method comprising providing, for each set of nozzles, a fire signal in accordance with the sequence: [nozzle position 1, nozzle position n, nozzle position 2, nozzle position (n-1), ... , nozzle position x], wherein nozzle position x is at or adjacent the centre of the set of nozzles.

Optionally, the method being performed in conjunction with a printer controller for supplying dot data to a printhead module comprising at least first and second rows configured to print ink of a similar type or color, at least some nozzles in the first row being aligned with respective corresponding nozzles in the second row in a direction of intended media travel relative to the printhead, the printhead module being configurable such that the nozzles in the fust and second pairs of rows are fired such that some dots output to print media are printed to by nozzles from the first pair of rows and at least some other dots output to print media are printed to by nozzles from the second pair of rows, the printer controller being configurable to supply dot data to the printhead module for printing.

Optionally, the method being performed in conjunction with a printer controller for supplying dot data to at least one printhead module, the at least one printhead module comprising a plurality of rows, each of the rows comprising a plurality of nozzles for ejecting ink, wherein the printhead module includes at least first and second rows configured to print ink of a similar type or color, the printer controller being configured to supply the dot data to the at least one printhead module such that, in the event a nozzle in the first row is faulty, a corresponding nozzle in the second row prints an ink dot at a position on print media at or adjacent a position where the faulty nozzle would otherwise have printed it.

Optionally, the method being performed in conjunction with a printer controller for receiving first data and manipulating the first data to produce dot data to be printed, the print controller including at least two serial outputs for supplying the dot data to at least one printhead, wherein each of the serial outputs is configured to supply dot data for at least two channels of the at least one printhead.

Optionally, the method being performed in conjunction with a printhead module including:
at least one row of print nozzles;

at least first and second shift registers for shifting in dot data supplied from a data source, wherein each shift register feeds dot data to a group of nozzles, and wherein each of the groups of the nozzles is interleaved with at least one of the other groups of the nozzles.

Optionally, the method being performed in conjunction with a printhead capable of printing a maximum of n of channels of print data, the printhead being configurable into:

a first mode, in which the printhead is configured to receive print data for a first number of the channels;
and a second mode, in which the printhead is configured to receive print data for a second number of the channels, wherein the first number is greater than the second number.

Optionally, the method being performed in conjunction with a printhead comprising a plurality of printhead modules, the printhead being wider than a reticle step used in fom-ting the modules, the printhead comprising at least two types of the modules, wherein each type is determined by its geometric shape in plan.

Optionally, the method being performed in conjunction with a printhead module including at least one row that comprises a plurality of sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, such that, for each set of nozzles, a fire signal is provided in accordance with the sequence: [nozzle position 1, nozzle position n, nozzle position 2, nozzle position (n-1), ... , nozzle position x], wherein nozzle 10 position x is at or adjacent the centre of the set of nozzles.

Optionally 1, the method being performed in conjunction with a printhead module including at least one row that comprises a plurality of adjacent sets of n adjacent nozzles, each of the nozzles being configured to expel the ink in response to a fire signal, the printhead being configured to output ink from nozzles at a first and nth position in 15 each set of nozzles, and then each next inward pair of nozzles in each set, until:

in the event n is an even number, all of the nozzles in each set has been fired; and in the event n is an odd number, all of the nozzles but a central nozzle in each set have been fired, and then to fire the central nozzle.

20 Optionally, the method being performed in conjunction with a printhead module for receiving dot data to be printed using at least two different inks and control data for controlling printing of the dot data, the printhead module including a communication input for receiving the dot data for the at least two colors and the control data.
Optionally, the method being performed in conjunction with a printhead module including at least one row of 25 printhead nozzles, at least one row including at least one displaced row portion, the displacement of the row portion including a component in a direction normal to that of a pagewidth to be printed.

Optionally, the method being performed in conjunction with a printhead module having a plurality of rows of nozzles configured to extend, in use, across at least part of a printable pagewidth, the nozzles in each row being 30 grouped into at least first and second fire groups, the printhead module being configured to sequentially fire, for each row, the nozzles of each fire group, such that each nozzle in the sequence from each fire group is fired simultaneously with respective corresponding nozzles in the sequence in the other fire groups, wherein the nozzles are fired row by row such that the nozzles of each row are all fired before the nozzles of each subsequent row.
Optionally, the method being performed in conjunction with a printhead module comprising at least first and second rows configured to print ink of a similar type or color, at least some nozzles in the first row being aligned with respective cocresponding nozzles in the second row in a direction of intended media travel relative to the printhead, the printhead module being configurable such that the nozzles in the first and second pairs of rows are fired such that some dots output to print media are printed to by nozzles from the first pair of rows and at least some other dots output to print media are printed to by nozzles from the second pair of rows.

Optionally, the method being performed in conjunction with a printer controller for providing data to a printhead module that includes:

at least one row of print nozzles;

at least first and second shift registers for shifting in dot data supplied from a data source, wherein each shift register feeds dot data to a group of nozzles, and wherein each of the groups of the nozzles is interleaved with at least one of the other groups of the nozzles.

Optionally, the method being perfonned in conjunction with a printhead module having a plurality of nozzles for expelling ink, the printhead module including a plurality of thermal sensors, each of the thermal sensors being configured to respond to a temperature at or adjacent at least one of the nozzles, the printhead module being configured to modify operation of the nozzles in response to the temperature rising above a first threshold.
Optionally, the method being performed in conjunction with a printhead module comprising a plurality of rows, each of the rows comprising a plurality of nozzles for ejecting ink, wherein the printhead module includes at least first and second rows configured to print ink of a similar type or color, and being configured such that, in the event a nozzle in the first row is faulty, a corresponding nozzle in the second row prints an ink dot at a position on print media at or adjacent a position where the faulty nozzle would otherwise have printed it.

In a fifth aspect the present invention provides a printhead module including:
at least one row of print nozzles;

at least two shift registers for shifting in dot data supplied from a data source to each of the at least one rows, wherein each print nozzle obtains dot data to be fired from an element of one of the shift registers.

Optionally, there is a one to one correspondence between the nozzles and elements of the two shift registers.
Optionally, each of the shift registers supplies dot data to about half of the nozzles.

Optionally the printhead module includes at least one pair of rows of the nozzles, the rows in each pair being offset with respect to each other by half the intra-row nozzle spacing.

Optionally, each of the at least two shift registers supplies dot data to at least some of the nozzles in at least one pair of rows.

Optionally the present invention provides a printhead comprising a plurality of printhead modules including:
at least one row of print nozzles;

at least two shift registers for shifting in dot data supplied from a data source to each of the at least one rows, wherein each print nozzle obtains dot data to be fired from an element of one of the shift registers.
Optionally, the printhead is a pagewidth printhead.

Optionally the printhead module is configured to receive dot data to which a method of at least partially compensating for errors in ink dot placement by at least one of a plurality of nozzles due to erroneous rotational displacement of a printhead module relative to a carrier has been applied, the nozzles being disposed on the printhead module, the method comprising the steps of:

(a) determining the rotational displacement;

(b) determining at least one correction factor that at least partially compensates for the ink dot displacement;
and (c) using the correction factor to alter the output of the ink dots to at least partially compensate for the rotational displacement.

Optionally the printhead module is configured to receive dot data to which a method of expelling ink has been applied, the method being applied to a printhead module including at least one row that comprises a plurality of adjacent sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, the method comprising providing, for each set of nozzles, a fire signal in accordance with the sequence: [nozzle position 1, nozzle position n, nozzle position 2, nozzle position (n-1), ... , nozzle position x], wherein nozzle position x is at or adjacent the centre of the set of nozzles.

Optionally the printhead module is configured to receive dot data to which a method of expelling ink has been applied, the method being applied to a printhead module including at least one row that comprises a plurality of sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, the method comprising the steps of:

(a) providing a fire signal to nozzles at a first and nth position in each set of nozzles;
(b) providing a fire signal to the next inward pair of nozzles in each set;

(c) in the event n is an even number, repeating step (b) until all of the nozzles in each set has been fired; and (d) in the event n is an odd number, repeating step (b) until all of the nozzles but a central nozzle in each set have been fired, and then firing the central nozzle.

Optionally the printhead module having been manufactured in accordance with a method of manufacturing a plurality of printhead modules, at least some of which are capable of being combined in pairs to form bilithic pagewidth printheads, the method comprising the step of laying out each of the plurality of printhead modules on a wafer substrate, wherein at least one of the printhead modules is right-handed and at least another is left-handed.

Optionally the printhead module including:
at least one row of print nozzles;

at least two shift registers for shifting in dot data supplied from a data source to each of the at least one rows, wherein each print nozzle obtains dot data to be fired from an element of one of the shift registers.

Optionally the printhead module installed in a printer comprising:

a printhead comprising at least the first elongate printhead module, the at least one printhead module including at least one row of print nozzles for expelling ink; and at least first and second printer controllers configured to receive print data and process the print data to output dot data to the printhead, wherein the first and second printer controllers are connected to a common input of the printhead.

Optionally the printhead module installed in a printer comprising:

a printhead comprising first and second elongate printhead modules, the printhead modules being parallel to each other and being disposed end to end on either side of a join region;

at least first and second printer controllers configured to receive print data and process the print data to output dot data to the printhead, wherein the fust printer controller outputs dot data only to the first printhead module and the second printer controller outputs dot data only to the second printhead module, wherein the printhead modules are configured such that no dot data passes between them.

Optionally the printhead module installed in a printer comprising:

a printhead comprising first and second elongate printhead modules, the printhead modules being parallel to each other and being disposed end to end on either side of a join region, wherein the first printhead module is longer than the second printhead module;

at least first and second printer controllers configured to receive print data and process the print data to output dot data to the printhead, wherein: the first printer controller outputs dot data to both the first printhead module and the second printhead module; and the second printer controller outputs dot data only to the second printhead module.

Optionally the printhead module installed in a printer comprising:

a printhead comprising first and second elongate printhead modules, the printhead modules being parallel to each other and being disposed end to end on either side of a join region, wherein the first printhead module is longer than the second printhead module;

at least first and second printer controllers configured to receive print data and process the print data to output dot data for the printhead, wherein: the fust printer controller outputs dot data to both the first printhead module and the second controller; and the second printer controller outputs dot data to the second printhead module, wherein the dot data output by the second printer controller includes dot data it generates and at least some of the dot data received from the fust printer controller.

Optionally the printhead module is in communication with a printer controller for supplying dot data to at least one printhead module and at least partially compensating for errors in ink dot placement by at least one of a plurality of nozzles on the printhead module due to erroneous rotational displacement of the printhead module relative to a carrier, the printer being configured to:

access a correction factor associated with the at least one printhead module;

detennine an order in which at least some of the dot data is supplied to at least one of the at least one printhead modules, the order being determined at least partly on the basis of the correction factor, thereby to at least partially compensate for the rotational displacement; and 5 supply the dot data to the printhead module.

Optionally the printhead module is in communication with a printer controller for supplying dot data to a printhead module having a plurality of nozzles for expelling ink, the printhead module including a plurality of thermal sensors, each of the thermal sensors being configured to respond to a temperature at or adjacent at least 10 one of the nozzles, the printer controller being configured to modify operation of at least some of the nozzles in response to the temperature rising above a first threshold.

Optionally the printhead module is in communication with a printer controller for controlling a printhead comprising at least one monolithic printhead module, the at least one printhead module having a plurality of rows 15 of nozzles configured to extend, in use, across at least part of a printable pagewidth of the printhead, the nozzles in each row being grouped into at least first and second fire groups, the printhead module being configured to sequentially fire, for each row, the nozzles of each fire group, such that each nozzle in the sequence from each fire group is fired simultaneously with respective corresponding nozzles in the sequence in the other fire groups, wherein the nozzles are fired row by row such that the nozzles of each row are all fired before the nozzles of each 20 subsequent row, wherein the printer controller is configured to provide one or more control signals that control the order of firing of the nozzles.

Optionally the printhead module is in communication with a printer controller for outputting to a printhead module:

25 dot data to be printed with at least two different inks; and control data for controlling printing of the dot data;

the printer controller including at least one communication output, each or the communication output being configured to output at least some of the control data and at least some of the dot data for the at least two inks.

Optionally the printhead module including at least one row of printhead nozzles, at least one row including at least one displaced row portion, the displacement of the row portion including a component in a direction normal to that of a pagewidth to be printed.

Optionally the printhead module is in communication with a printer controller for supplying print data to at least one printhead module capable of printing a maximum of n of channels of print data, the at least one printhead module being configurable into:

a first mode, in which the printhead module is configured to receive data for a first number of the channels; and a second mode, in which the printhead module is configured to receive print data for a second number of the channels, wherein the first number is greater than the second number;

wherein the printer controller is selectively configurable to supply dot data for the first and second modes.
Optionally the printhead module is in communication with a printer controller for supplying data to a printhead comprising a plurality of printhead modules, the printhead being wider than a reticle step used in forming the modules, the printhead comprising at least two types of the modules, wherein each type is determined by its geometric shape in plan.

Optionally the printhead module is used in conjunction with a printer controller for supplying one or more control signals to a printhead module, the printhead module including at least one row that comprises a plurality of sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, such that:

(a) a fire signal is provided to nozzles at a fust and nth position in each set of nozzles;
(b) a fire signal is provided to the next inward pair of nozzles in each set;

(c) in the event n is an even number, step (b) is repeated until all of the nozzles in each set has been fired;
and (d) in the event n is an odd number, step (b) is repeated until all of the nozzles but a central nozzle in each set have been fired, and then the central nozzle is fired.

Optionally the printhead module is used in conjunction with a printer controller for supplying one or more control signals to a printhead module, the printhead module including at least one row that comprises a plurality of adjacent sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, the method comprising providing, for each set of nozzles, a fire signal in accordance with the sequence: [nozzle position 1, nozzle position n, nozzle position 2, nozzle position (n-1), ... , nozzle position x], wherein nozzle position x is at or adjacent the centre of the set of nozzles.

Optionally the printhead module is in communication with a printer controller for supplying dot data to a printhead module comprising at least first and second rows configured to print ink of a similar type or color, at least some nozzles in the first row being aligned with respective con:esponding nozzles in the second row in a direction of intended media travel relative to the printhead, the printhead module being configurable such that the nozzles in the first and second pairs of rows are fired such that some dots output to print media are printed to by nozzles from the first pair of rows and at least some other dots output to print media are printed to by nozzles from the second pair of rows, the printer controller being configurable to supply dot data to the printhead module for printing.

Optionally the printhead module is in communication with a printer controller for supplying dot data to at least one printhead module, the at least one printhead module comprising a plurality of rows, each of the rows comprising a plurality of nozzles for ejecting ink, wherein the printhead module includes at least first and second rows configured to print ink of a similar type or color, the printer controller being configured to supply the dot data to the at least one printhead module such that, in the event a nozzle in the first row is faulty, a corresponding nozzle in the second row prints an ink dot at a position on print media at or adjacent a position where the faulty nozzle would otherwise have printed it.

Optionally the printhead module is in communication with a printer controller for receiving first data and manipulating the first data to produce dot data to be printed, the print controller including at least two serial outputs for supplying the dot data to at least one printhead.

Optionally the printhead module including:
at least one row of print nozzles;

at least first and second shift registers for shifting in dot data supplied from a data source, wherein each shift register feeds dot data to a group of nozzles, and wherein each of the groups of the nozzles is interleaved with at least one of the other groups of the nozzles.

Optionally the printhead module being capable of printing a maximum of n of channels of print data, the printhead being configurable into:

a fust mode, in which the printhead is configured to receive print data for a first number of the channels;
and a second mode, in which the printhead is configured to receive print data for a second number of the channels, wherein the first number is greater than the second number.

Optionally a printhead comprising a plurality of printhead modules, the printhead being wider than a reticle step used in forming the modules, the printhead comprising at least two types of the modules, wherein each type is determined by its geometric shape in plan.

Optionally the printhead module including at least one row that comprises a plurality of sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, such that, for each set of nozzles, a fire signal is provided in accordance with the sequence: [nozzle position 1, nozzle position n, nozzle position 2, nozzle position (n-1), ... , nozzle position x], wherein nozzle position x is at or adjacent the centre of the set of nozzles.

Optionally the printhead module including at least one row that comprises a plurality of adjacent sets of n adjacent nozzles, each of the nozzles being configured to expel the ink in response to a fire signal, the printhead being configured to output ink from nozzles at a first and nth position in each set of nozzles, and then each next inward pair of nozzles in each set, until:

in the event n is an even number, all of the nozzles in each set has been fired; and in the event n is an odd number, all of the nozzles but a central nozzle in each set have been fired, and then to fire the central nozzle.

Optionally a printhead module for receiving dot data to be printed using at least two different inks and control data for controlling printing of the dot data, the printhead module including a communication input for receiving the dot data for the at least two colors and the control data.

Optional a printhead module including at least one row of printhead nozzles, at least one row including at least one displaced row portion, the displacement of the row portion including a component in a direction normal to that of a pagewidth to be printed.

Optionally a printhead module having a plurality of rows of nozzles configured to extend, in use, across at least part of a printable pagewidth, the nozzles in each row being grouped into at least first and second fire groups, the printhead module being configured to sequentially fire, for each row, the nozzles of each fire group, such that each nozzle in the sequence from each fire group is fired simultaneously with respective corresponding nozzles in the sequence in the other fire groups, wherein the nozzles are fired row by row such that the nozzles of each row are all fired before the nozzles of each subsequent row.

Optionally a printhead module comprising at least first and second rows configured to print ink of a similar type or color, at least some nozzles in the first row being aligned with respective corresponding nozzles in the second row in a direction of intended media travel relative to the printhead, the printhead module being configurable such that the nozzles in the first and second pairs of rows are fired such that some dots output to print media are printed to by nozzles from the first pair of rows and at least some other dots output to print media are printed to by nozzles from the second pair of rows.

Optionally a printhead module is in communication with a printer controller for providing data to a printhead module that includes:

at least one row of print nozzles;

at least first and second shift registers for shifting in dot data supplied from a data source, wherein each shift register feeds dot data to a group of nozzles, and wherein each of the groups of the nozzles is interleaved with at least one of the other groups of the nozzles.

Optionally a printhead module having a plurality of nozzles for expelling ink, the printhead module including a plurality of thermal sensors, each of the thermal sensors being configured to respond to a temperature at or adjacent at least one of the nozzles, the printhead module being configured to modify operation of the nozzles in response to the temperature rising above a first threshold.

Optionally a printhead module comprising a plurality of rows, each of the rows comprising a plurality of nozzles for ejecting ink, wherein the printhead module includes at least first and second rows configured to print ink of a similar type or color, and being configured such that, in the event a nozzle in the fust row is faulty, a corresponding nozzle in the second row prints an ink dot at a position on print media at or adjacent a position where the faulty nozzle would otherwise have printed it.

In a sixth aspect the present invention provides printer comprising:

a printhead comprising at least a first elongate printhead module, the at least one printhead module including at least one row of print nozzles for expelling ink; and at least first and second printer controllers configured to receive peint data and process the print data to output dot data to the printhead, wherein the first and second printer controllers are connected to a common input 5 of the printhead.

Optionally the printer including at least one synchronization means between the first and second printer controllers for synchronizing the supply of dot by the printer controllers.

10 Optionally the printer configured such that the first and second printer controllers sequentially provide the dot data to the common input.

Optionally the printer further including a second printhead module, the printer being configured such that: the fust printer controller outputs dot data to both the first printhead module and the second printhead module; and the 15 second printer controller outputs dot data only to the second printhead module.

Optionally the printhead modules are configured such that no dot data passes between them.

Optionally each of the printer controllers is configurable to supply the dot data to printhead modules of a plurality 20 of different lengths.

Optionally the printhead is a pagewidth printhead.

In a further aspect the present invention provides a print engine comprising:
25 a carrier;

a printhead comprising at least a first elongate printhead module, the at least one printhead module including at least one row of print nozzles for expelling ink; and at least first and second printer controllers configured to receive print data and process the print data to output dot data to the printhead, wherein the first and second printer controllers are connected to a common input 30 of the printhead.

Optionally the printer including at least one synchronization means between the first and second printer controllers for synchronizing the supply of dot by the printer controllers.

Optionally the printer configured such that the first and second printer controllers alternately provide the dot data to the common input.

Optionally the printer further including a second printhead module, the printer being configured such that: the first printer controller outputs dot data to both the first printhead module and the second printhead module; and the second printer controller outputs dot data only to the second printhead module.

Optionally the printhead modules are configured such that no dot data passes between them.

Optionally each of the printer controllers is configurable to supply the dot data to printhead modules of a plurality of different lengths.

Optionally the printhead is a pagewidth printhead.

In a further aspect the present invention provides a printer comprising:

a printhead comprising at least a first elongate printhead module, the at least one printhead module including at least first and second rows of print nozzles for expelling ink;
and at least first and second printer controllers configured to receive print data and process the print data to output dot data to the printhead, wherein the first and second printer controllers are connected to the printhead to supply data for the first and second rows of nozzles, respectively.

Optionally the printer including at least one synchronization means between the first and second printer controllers for synchronizing the supply of dot by the printer controllers.

Optionally the printhead modules are configured such that no dot data passes between them.

Optionally the printhead is a pagewidth printhead.

Optionally the printer is for implementing a method of at least partially compensating for errors in ink dot placement by at least one of a plurality of nozzles due to erroneous rotational displacement of a printhead module relative to a carrier, the nozzles being disposed on the printhead module, the method comprising the steps of:

(a) determining the rotational displacement;

(b) determining at least one correction factor that at least partially compensates for the ink dot displacement;
and (c) using the correction factor to alter the output of the ink dots to at least partially compensate for the rotational displacement.

Optionally the printer is for implementing a method of expelling ink from a printhead module including at least one row that comprises a plurality of adjacent sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, the method comprising providing, for each set of nozzles, a fire signal in accordance with the sequence: [nozzle position 1, nozzle position n, nozzle position 2, nozzle position (n-1), ... , nozzle position x], wherein nozzle position x is at or adjacent the centre of the set of nozzles.

Optionally the printer is for implementing a method of expelling ink from a printhead module including at least one row that comprises a plurality of sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, the method comprising the steps of:

(a) providing a fire signal to nozzles at a first and nth position in each set of nozzles;
(b) providing a fire signal to the next inward pair of nozzles in each set;

(c) in the event n is an even number, repeating step (b) until all of the nozzles in each set has been fired; and (d) in the event n is an odd number, repeating step (b) until all of the nozzles but a central nozzle in each set have been fired, and then firing the central nozzle.

Optionally the printer is manufactured in accordance with a method of manufacturing a plurality of printhead modules, at least some of which are capable of being combined in pairs to form bilithic pagewidth printheads, the method comprising the step of laying out each of the plurality of printhead modules on a wafer substrate, wherein at least one of the printhead modules is right-handed and at least another is left-handed.

Optionally the printer including a printhead module including:

at least one row of print nozzles;

at least two shift registers for shifting in dot data supplied from a data source to each of the at least one rows, wherein each print nozzle obtains dot data to be fired from an element of one of the shift registers.

Optionally the printer comprising:

a printhead comprising first and second elongate printhead modules, the printhead modules being parallel to each other and being disposed end to end on either side of a join region;

at least first and second printer controllers configured to receive print data and process the print data to output dot data to the printhead, wherein the first printer controller outputs dot data only to the first printhead module and the second printer controller outputs dot data only to the second printhead module, wherein the printhead modules are configured such that no dot data passes between them.

Optionally the printer comprising:

a printhead comprising first and second elongate printhead modules, the printhead modules being parallel to each other and being disposed end to end on either side of a join region, wherein the first printhead module is longer than the second printhead module;

at least first and second printer controllers configured to receive print data and process the print data to output dot data to the printhead, wherein: the first printer controller outputs dot data to both the fust printhead module and the second printhead module; and the second printer controller outputs dot data only to the second printhead module.

Optionally the printer comprising:

a printhead comprising first and second elongate printhead modules, the printhead modules being parallel to each other and being disposed end to end on either side of a join region, wherein the first printhead'module is longer than the second printhead module;

at least first and second printer controllers configured to receive print data and process the print data to output dot data for the printhead, wherein: the first printer controller outputs dot data to both the first printhead module and the second controller; and the second printer controller outputs dot data to the second printhead module, wherein the dot data output by the second printer controller includes dot data it generates and at least some of the dot data received from the first printer controller.

Optionally the printer including at least one printhead module, configured for at least partially compensating for errors in ink dot placement by at least one of a plurality of nozzles on the printhead module due to erroneous rotational displacement of the printhead module relative to a carrier, the printer being configured to:

access a correction factor associated with the at least one printhead module;

determine an order in which at least some of the dot data is supplied to at least one of the at least one printhead modules, the order being deterrnined at least partly on the basis of the correction factor, thereby' to at least partially compensate for the rotational displacement; and supply the dot data to the printhead module.

Optionally the printer including a printhead module having a plurality of nozzles for expelling ink, the printhead module including a plurality of thermal sensors, each of the thenmal sensors being configured to respond to a temperature at or adjacent at least one of the nozzles, the printer being configured to modify operation of at least some of the nozzles in response to the temperature rising above a first threshold.

Optionally the printer controls a printhead comprising at least one monolithic printhead module, the at least one printhead module having a plurality of rows of nozzles configured to extend, in use, across at least part of a printable pagewidth of the printhead, the nozzles in each row being grouped into at least first and second fire groups, the printhead module being configured to sequentially fire, for each row, the nozzles of each fire group, such that each nozzle in the sequence from each fire group is fired simultaneously with respective corresponding nozzles in the sequence in the other fire groups, wherein the nozzles are fired row by row such that the nozzles of each row are all fired before the nozzles of each subsequent row, wherein the printer controller is configured to provide one or more control signals that control the order of firing of the nozzles.

Optionally the printer including a printer controller for sending to a printhead:
dot data to be printed with at least two different inks; and control data for controlling printing of the dot data;

the printer controller including at least one communication output, each or the communication output being configured to output at least some of the control data and at least some of the dot data for the at least two inks.

Optionally the printer including a printer controller for supplying data to a printhead module including at least one row of printhead nozzles, at least one row including at least one displaced row portion, the displacement of the row portion including a component in a direction normal to that of a pagewidth to be printed.

5 Optionally the printer including a printer controller for supplying print data to at least one printhead module capable of printing a maximum of n of channels of print data, the at least one printhead module being configurable into:

a first mode, in which the printhead module is configured to receive data for a first number of the channels; and 10 a second mode, in which the printhead module is configured to receive print data for a second number of the channels, wherein the first number is greater than the second number;

wherein the printer controller is selectively configurable to supply dot data for the first and second modes.
Optionally the printer including a printer controller for supplying data to a printhead comprising a plurality of 15 printhead modules, the printhead being wider than a reticle step used in fonning the modules, the printhead comprising at least two types of the modules, wherein each type is determined by its geometric shape.in plan.
Optionally the printer including a printer controller for supplying one or more control signals to a printhead module, the printhead module including at least one row that comprises a plurality of sets of n adjacent nozzles, 20 each of the nozzles being configured to expel ink in response to a fire signal, such that:

(a) a fire signal is provided to nozzles at a first and nth position in each set of nozzles;
(b) a fire signal is provided to the next inward pair of nozzles in each set;

(c) in the event n is an even number, step (b) is repeated until all of the nozzles in each set has been fired;
and 25 (d) in the event n is an odd number, step (b) is repeated until all of the nozzles but a central nozzle in each set have been fired, and then the central nozzle is fired.

Optionally the printer including a printer controller for supplying one or more control signals to a printhead module, the printhead module including at least one row that comprises a plurality of adjacent sets of n adjacent 30 nozzles, each of the nozzles being configured to expel ink in response to a fire signal, the method comprising providing, for each set of nozzles, a fire signal in accordance with the sequence: [nozzle position 1, nozzle position n, nozzle position 2, nozzle position (n-1), ... , nozzle position x], wherein nozzle position x is at or adjacent the centre of the set of nozzles.

Optionally the printer including a printer controller for supplying dot data to a printhead module comprising at least first and second rows configured to print ink of a similar type or color, at least some nozzles in the first row being aligned with respective corresponding nozzles in the second row in a direction of intended media travel relative to the printhead, the printhead module being configurable such that the nozzles in the first and second pairs of rows are fired such that some dots output to print media are printed to by nozzles from the first pair of rows and at least some other dots output to print media are printed to by nozzles from the second pair of rows, the printer controller being configurable to supply dot data to the printhead module for printing.

Optionally the printer including a printer controller for supplying dot data to at least one printhead module, the at least one printhead module comprising a plurality of rows, each of the rows comprising a plurality of nozzles for ejecting ink, wherein the printhead module includes at least first and second rows configured to print ink of a similar type or color, the printer controller being configured to supply the dot data to the at least one printhead module such that, in the event a nozzle in the first row is faulty, a corresponding nozzle in the second row prints an ink dot at a position on print media at or adjacent a position where the faulty nozzle would otherwise have printed it.

Optionally the printer including a printer controller for receiving fust data and manipulating the first data to produce dot data to be printed, the print controller including at least two serial outputs for supplying the dot data to at least one printhead.

Optionally the printer including a printer controller for supplying data to a printhead module including:
at least one row of print nozzles;

at least first and second shift registers for shifting in dot data supplied from a data source, wherein each shift register feeds dot data to a group of nozzles, and wherein each of the groups of the nozzles is interleaved with at least one of the other groups of the nozzles.

Optionally the printer including a printer controller for supplying data to a printhead capable of printing a maximum of n of channels of print data, the printhead being configurable into:

a first mode, in which the printhead is configured to receive print data for a first number of the channels;
and a second mode, in which the printhead is configured to receive print data for a second number of the channels, wherein the first number is greater than the second number.

Optionally the printer including a printer controller for supplying data to a printhead comprising a plurality of printhead modules, the printhead being wider than a reticle step used in forming the modules, the printhead comprising at least two types of the modules, wherein each type is determined by its geometric shape in plan.

Optionally the printer including a printer controller for supplying data to a printhead module including at least one row that comprises a plurality of sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, such that, for each set of nozzles, a fire signal is provided in accordance with the sequence: [nozzle position 1, nozzle position n, nozzle position 2, nozzle position (n-1), ... , nozzle position x], wherein nozzle position x is at or adjacent the centre of the set of nozzles.

Optionally the printer including a printer controller for supplying data to a printhead module including at least one row that comprises a plurality of adjacent sets of n adjacent nozzles, each of the nozzles being configured to expel the ink in response to a fire signal, the printhead being configured to output ink from nozzles at a first and nth position in each set of nozzles, and then each next inward pair of nozzles in each set, until:

in the event n is an even number, all of the nozzles in each set has been fired; and in the event n is an odd number, all of the nozzles but a central nozzle in each set have been fired, and then to fire the central nozzle.

Optionally the printer including a printer controller for supplying data to a printhead module for receiving dot data to be printed using at least two different inks and control data for controlling printing of the dot data, the printhead module including a communication input for receiving the dot data for the at least two colors and the control data.
Optionally the printer including a printer controller for supplying data to a printhead module including at least one row of printhead nozzles, at least one row including at least one displaced row portion, the displacement of the row portion including a component in a direction normal to that of a pagewidth to be printed.

Optionally the printer including a printer controller for supplying data to a printhead module having a plurality of rows of nozzles configured to extend, in use, across at least part of a printable pagewidth, the nozzles in each row being grouped into at least first and second fire groups, the printhead module being configured to sequentially fire, for each row, the nozzles of each fire group, such that each nozzle in the sequence from each fire group is fired simultaneously with respective corresponding nozzles in the sequence in the other fire groups, wherein the nozzles are fired row by row such that the nozzles of each row are all fired before the nozzles of each subsequent row.
Optionally the printer including a printer controller for supplying data to a printhead module comprising at least first and second rows configured to print ink of a similar type or color, at least some nozzles in the first row being aligned with respective corresponding nozzles in the second row in a direction of intended media travel relative to the printhead, the printhead module being configurable such that the nozzles in the first and second pairs of rows are fired such that some dots output to print media are printed to by nozzles from the first pair of rows and at least some other dots output to print media are printed to by nozzles from the second pair of rows.

Optionally the printer including a printer controller for providing data to a printhead module that includes:
at least one row of print nozzles;

at least first and second shift registers for shifting in dot data supplied from a data source, wherein each shift register feeds dot data to a group of nozzles, and wherein each of the groups of the nozzles is interleaved with at least one of the other groups of the nozzles.

Optionally the printer including a printer controller for supplying data to a printhead module having a plurality of nozzles for expelling ink, the printhead module including a plurality of thermal sensors, each of the thermal sensors being configured to respond to a temperature at or adjacent at least one of the nozzles, the printhead module being configured to modify operation of the nozzles in response to the temperature rising above a first threshold.

Optionally the printer including a printer controller for supplying data to a printhead module comprising a plurality of rows, each of the rows comprising a plurality of nozzles for ejecting ink, wherein the printhead module includes at least first and second rows configured to print ink of a similar type or color, and being configured such that, in the event a nozzle in the first row is faulty, a corresponding nozzle in the second row prints an ink dot at a position on print media at or adjacent a position where the faulty nozzle would otherwise have printed it.

In a seventh aspect the present invention provides a printer comprising:

a printhead comprising first and second elongate printhead modules, the printhead modules being parallel to each other and being disposed end to end on either side of a join region;

at least first and second printer controllers configured to receive print data and process the print data to output dot data to the printhead, wherein the first printer controller outputs dot data only to the first printhead module and the second printer controller outputs dot data only to the second printhead module, wherein the printhead modules are configured such that no dot data passes between them.

Optionally the printer includes at least one synchronization means between the first and second printer controllers for synchronizing the supply of dot by the printer controllers.

Optionally each of the printer controllers is configurable to supply the dot data to a printhead module of arbitrary length.

Optionally the first and second printhead modules are equal in length.
Optionally the first and second printhead modules are unequal in length.
Optionally the printhead is a pagewidth printhead.

In a further aspect the present invention provides a print engine comprising:
a carrier;

a printhead comprising first and second elongate printhead modules, the printhead modules being mounted parallel to each other end to end on the carrier on either side of a join region;

at least first and second printer controllers mounted on the carrier and being configured to receive print data and process the print data to output dot data to the printhead, wherein the first printer controller outputs dot data only to the first printhead module and the second printer controller outputs dot data only to the second printhead module, wherein the printhead modules are configured such that no dot data passes between them.

Optionally the print engine includes at least one synchronization means between the first and second printer controllers for synchronizing the supply of dot by the printer controllers.

Optionally each of the printer controllers is configurable to supply the dot data to a printhead module of arbitrary 5 length.

Optionally the first and second printhead modules are equal in length.
Optionally the first and second printhead modules are unequal in length.

Optionally the printhead is a pagewidth printhead.

Optionally the printer is for implementing a method of at least partially compensating for errors in ink dot placement by at least one of a plurality of nozzles due to erroneous rotational displacement of a printhead module relative to a carrier, the nozzles being disposed on the printhead module, the method comprising the steps of:

(a) determining the rotational displacement;

(b) determining at least one correction factor that at least partially compensates for the ink dot displacement;
and (c) using the correction factor to alter the output of the ink dots to at least partially compensate for the rotational displacement.

Optionally the printer is for implementing a method of expelling ink from a printhead module including at least one row that comprises a plurality of adjacent sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, the method comprising providing, for each set of nozzles, a fire. signal in accordance with the sequence: [nozzle position 1, nozzle position n, nozzle position 2, nozzle position (n-1), ... , nozzle position x], wherein nozzle position x is at or adjacent the centre of the set of nozzles.

Optionally the printer is for implementing a method of expelling ink from a printhead module including at least one row that comprises a plurality of sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, the method comprising the steps of:

(a) providing a fire signal to nozzles at a first and nth position in each set of nozzles;

(b) providing a fire signal to the next inward pair of nozzles in each set;

(c) in the event n is an even number, repeating step (b) until all of the nozzles in each set has been fired; and (d) in the event n is an odd number, repeating step (b) until all of the nozzles but a central nozzle in each set have been fired, and then firing the central nozzle.

Optionally the printer is manufactured in accordance with a method of manufacturing a plurality of printhead modules, at least some of which are capable of being combined in pairs to form bilithic pagewidth printheads, the method comprising the step of laying out each of the plurality of printhead modules on a wafer substrate, wherein at least one of the printhead modules is right-handed and at least another is left-handed.

Optionally the printer includes a printhead module including:
at least one row of print nozzles;

at least two shift registers for shifting in dot data supplied from a data source to each of the at least one rows, wherein each print nozzle obtains dot data to be fired from an element of one of the shift registers.

Optionally the printer comprises:

a printhead comprising at least a first elongate printhead module, the at least one printhead module including at least one row of print nozzles for expelling ink; and at least first and second printer controllers configured to receive print data and process the print data to output dot data to the printhead, wherein the first and second printer controllers are connected to a common input of the printhead.

Optionally the printer comprises:

a printhead comprising first and second elongate printhead modules, the printhead modules being parallel to each other and being disposed end to end on either side of a join region, wherein the first printhead module is longer than the second printhead module;

at least first and second printer controllers configured to receive print data and process the print data to output dot data to the printhead, wherein: the first printer controller outputs dot data to both the first printhead module and the second printhead module; and the second printer controller outputs dot data only to the second printhead module.

Optionally the printer comprises:

a printhead comprising first and second elongate printhead modules, the printhead modules being parallel to each other and being disposed end to end on either side of a join region, wherein the first printhead module is longer than the second printhead module;

at least first and second printer controllers configured to receive print data and process the print data to output dot data for the printhead, wherein: the first printer controller outputs dot data to both the first printhead module and the second controller; and the second printer controller outputs dot data to the second printhead module, wherein the dot data output by the second printer controller includes dot data it generates and at least some of the dot data received from the fust printer controller.

Optionally the printer comprises at least one printhead module, configured for at least partially compensating for errors in ink dot placement by at least one of a plurality of nozzles on the printhead module due to erroneous rotational displacement of the printhead module relative to a carrier, the printer being configured to:

access a correction factor associated with the at least one printhead module;

determine an order in which at least some of the dot data is supplied to at least one of the at least one printhead modules, the order being determined at least partly on the basis of the correction factor, thereby to at least partially compensate for the rotational displacement; and supply the dot data to the printhead module.

Optionally the printer comprises a printhead module having a plurality of nozzles for expelling ink, the printhead module including a plurality of thermal sensors, each of the thermal sensors being configured to respond to a temperature at or adjacent at least one of the nozzles, the printer being configured to modify operation of at least some of the nozzles in response to the temperature rising above a first threshold.

Optionally the printer controls a printhead comprising at least one monolithic printhead module, the at least one printhead module having a plurality of rows of nozzles configured to extend, in use, across at least part of a printable pagewidth of the printhead, the nozzles in each row being grouped into at least first and second fire groups, the printhead module being configured to sequentially fire, for each row, the nozzles of each fire group, such that each nozzle in the sequence from each fire group is fired simultaneously with respective corresponding nozzles in the sequence in the other fire groups, wherein the nozzles are fired row by row such that the nozzles of each row are all fired before the nozzles of each subsequent row, wherein the printer controller is configured to provide one or more control signals that control the order of firing of the nozzles.

Optionally the printer includes a printer controller for sending to a printhead:

dot data to be printed with at least two different inks; and control data for controlling printing of the dot data;

the printer controller including at least one communication output, each or the communication output being configured to output at least some of the control data and at least some of the dot data for the at least two inks.

Optionally the printer includes a printer controller for supplying data to a printhead module including at least one row of printhead nozzles, at least one row including at least one displaced row portion, the displacement of the row portion including a component in a direction normal to that of a pagewidth to be printed.

Optionally the printer includes a printer controller for supplying print data to at least one printhead module capable of printing a maximum of n of channels of print data, the at least one printhead module being configurable into:

a first mode, in which the printhead module is configured to receive data for a first number of the channels; and a second mode, in which the printhead module is configured to receive print data for a second number of the channels, wherein the first number is greater than the second number;

wherein the printer controller is selectively configurable to supply dot data for the first and second modes.

Optionally the printer includes a printer controller for supplying data to a printhead comprising a plurality of printhead modules, the printhead being wider than a reticle step used in forming the modules, the printhead comprising at least two types of the modules, wherein each type is determined by its geometric shape in plan.

Optionally the printer includes a printer controller for supplying one or more control signals to a printhead module, the printhead module including at least one row that comprises a plurality of sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, such that:

(a) a fire signal is provided to nozzles at a first and nth position in each set of nozzles;
(b) a fire signal is provided to the next inward pair of nozzles in each set;

(c) in the event n is an even number, step (b) is repeated until all of the nozzles in each set has been fired;
and (d) in the event n is an odd number, step (b) is repeated until all of the nozzles but a central nozzle in each set have been fired, and then the central nozzle is fired.

Optionally the printer includes a printer controller for supplying one or more control signals to a printhead module, the printhead module including at least one row that comprises a plurality of adjacent sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, the method comprising providing, for each set of nozzles, a fire signal in accordance with the sequence: [nozzle position 1, nozzle position n, nozzle position 2, nozzle position (n-1), ... , nozzle position x], wherein nozzle position x is at or adjacent the centre of the set of nozzles.

Optionally the printer includes a printer controller for supplying dot data to a printhead module comprising at least first and second rows configured to print ink of a similar type or color, at least some nozzles in the first row being aligned with respective corresponding nozzles in the second row in a direction of intended media travel relative to the printhead, the printhead module being configurable such that the nozzles in the first and second pairs of rows are fired such that some dots output to print media are printed to by nozzles from the fust pair of rows and at least some other dots output to print media are printed to by nozzles from the second pair of rows, the printer controller being configurable to supply dot data to the printhead module for printing.

Optionally the printer includes a printer controller for supplying dot data to at least one printhead module, the at least one printhead module comprising a plurality of rows, each of the rows comprising a plurality of nozzles for ejecting ink, wherein the printhead module includes at least first and second rows configured to print ink of a similar type or color, the printer controller being configured to supply the dot data to the at least one printhead module such that, in the event a nozzle in the first row is faulty, a corresponding nozzle in the second row prints an ink dot at a position on print media at or adjacent a position where the faulty nozzle would otherwise have printed it.

Optionally the printer includes a printer controller for receiving first data and manipulating the first data to produce dot data to be printed, the print controller including at least two serial outputs for supplying the dot data to at least one printhead.

Optionally the printer includes a printer controller for supplying data to a printhead module including:
at least one row of print nozzles;

at least first and second shift registers for shifting in dot data supplied from a data source, wherein each shift register feeds dot data to a group of nozzles, and wherein each of the groups of the nozzles is interleaved with at least one of the other groups of the nozzles.

5 Optionally the printer includes a printer controller for supplying data to a printhead capable of printing a maximum of n of channels of print data, the printhead being configurable into:

a first mode, in which the printhead is configured to receive print data for a first number of the channels;
and a second mode, in which the printhead is configured to receive print data for a second number of the 10 channels, wherein the first number is greater than the second number.

Optionally the printer includes a printer controller for supplying data to a printhead comprising a plurality of printhead modules, the printhead being wider than a reticle step used in forming the modules, the printhead comprising at least two types of the modules, wherein each type is determined by its geometric shape in plan.

Optionally the printer includes a printer controller for supplying data to a printhead module including at least one row that comprises a plurality of sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, such that, for each set of nozzles, a fire signal is provided in accordance with the sequence: [nozzle position 1, nozzle position n, nozzle position 2, nozzle position (n-1), ... , nozzle position x], wherein nozzle position x is at or adjacent the centre of the set of nozzles.

Optionally the printer includes a printer controller for supplying data to a printhead module including at least one row that comprises a plurality of adjacent sets of n adjacent nozzles, each of the nozzles being configured to expel the ink in response to a fire signal, the printhead being configured to output ink from nozzles at a first and nth position in each set of nozzles, and then each next inward pair of nozzles in each set, until:
in the event n is an even number, all of the nozzles in each set has been fired; and in the event n is an odd number, all of the nozzles but a central nozzle in each set have been fired, and then to fire the central nozzle.

Optionally the printer includes a printer controller for supplying data to a printhead module for receiving dot data to be printed using at least two different inks and control data for controlling printing of the dot data, the printhead module including a communication input for receiving the dot data for the at least two colors and the control data.

Optionally the printer includes a printer controller for supplying data to a printhead module including at least one row of printhead nozzles, at least one row including at least one displaced row portion, the displacement of the row portion including a component in a direction normal to that of a pagewidth to be printed.

Optionally the printer includes a printer controller for supplying data to a printhead module having a plurality of rows of nozzles configured to extend, in use, across at least part of a printable pagewidth, the nozzles in each row being grouped into at least first and second fire groups, the printhead module being configured to sequentially fire, for each row, the nozzles of each fire group, such that each nozzle in the sequence from each fire group is fired simultaneously with respective corresponding nozzles in the sequence in the other fire groups, wherein the nozzles are fired row by row such that the nozzles of each row are all fired before the nozzles of each subsequent row.
Optionally the printer includes a printer controller for supplying data to a printhead module comprising at least first and second rows configured to print ink of a similar type or color, at least some nozzles in the first row being aligned with respective corresponding nozzles in the second row in a direction of intended media travel relative to the printhead, the printhead module being configurable such that the nozzles in the first and second pairs of rows are fired such that some dots output to print media are printed to by nozzles from the first pair of rows and at least some other dots output to print media are printed to by nozzles from the second pair of rows.

Optionally the printer includes a printer controller for providing data to a printhead module that includes:
at least one row of print nozzles;

at least first and second shift registers for shifting in dot data supplied-from a data source, wherein each shift register feeds dot data to a group of nozzles, and wherein each of the groups of the nozzles is interleaved with at least one of the other groups of the nozzles.

Optionally the printer includes a printer controller for supplying data to a printhead module having a plurality of nozzles for expelling inlc, the printhead module including a plurality of thermal sensors, each of the thermal sensors being configured to respond to a temperature at or adjacent at least one of the nozzles, the printhead module being configured to modify operation of the nozzles in response to the temperature rising above a first threshold.

Optionally the printer includes a printer controller for supplying data to a printhead module comprising a plurality of rows, each of the rows comprising a plurality of nozzles for ejecting ink, wherein the printhead module includes at least first and second rows configured to print ink of a similar type or color, and being configured such that, in the event a nozzle in the first row is faulty, a corresponding nozzle in the second row prints an ink dot at a position on print media at or adjacent a position where the faulty nozzle would otherwise have printed it.
In an eighth aspect the present invention provides a printer comprising:

a printhead comprising first and second elongate printhead modules, the printhead modules being parallel to each other and being disposed end to end on either side of a join region, wherein the first printhead module is longer than the second printhead module;

at least first and second printer controllers configured to receive print data and process the print data to output dot data to the printhead, wherein: the first printer controller outputs dot data to both the first printhead module and the second printhead module; and the second printer controller outputs dot data only to the second printhead module.

Optionally the printhead modules are configured such that no dot data passes between them.

Optionally the printer includes at least one synchronization means between the first and second printer controllers for synchronizing the supply of dot data by the printer controllers.

Optionally each of the printer controllers is configurable to supply the dot data to printhead modules of a plurality of different lengths.

Optionally the printhead is a pagewidth printhead.

In a further aspect the present invention provides a print engine comprising:
a carrier;

a printhead comprising first and second elongate printhead modules, the printhead modules being mounted parallel to each other end to end on the carrier on either side of a join region, wherein the first printhead module is longer than the second printhead module;

at least first and second printer controllers mounted on the carrier and being configured to receive print data and process the print data to output dot data to the printhead, wherein:
the first printer controller outputs dot data to both the first printhead module and the second printhead module; and the second printer controller outputs dot data only to the second printhead module.

Optionally the printhead modules are configured such that no dot data passes between them.

Optionally the print engine includes at least one synchronization means between the first and second printer controllers for synchronizing the supply of dot by the printer controllers.

Optionally each of the printer controllers is configurable to supply the dot data to printhead modules of a plurality of different lengths.

Optionally the printhead is a pagewidth printhead.

Optionally the printer is for implementing a method of at least partially compensating for errors in ink dot placement by at least one of a plurality of nozzles due to erroneous rotational displacement of a printhead module relative to a carrier, the nozzles being disposed on the printhead module, the method comprising the steps of:

(a) determining the rotational displacement;

(b) determining at least one correction factor that at least partially compensates for the ink dot displacement;
and (c) using the correction factor to alter the output of the ink dots to at least partially compensate for the rotational displacement.

Optionally the printer is for implementing a method of expelling ink from a printhead module including at least one row that comprises a plurality of adjacent sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, the method comprising providing, for each set of nozzles, a fire signal in accordance with the sequence: [nozzle position 1, nozzle posirion n, nozzle position 2, nozzle position (n-1), ... , nozzle position x], wherein nozzle position x is at or adjacent the centre of the set of nozzles.

Optionally the printer is for implementing a method of expelling ink from a printhead module including at least one row that comprises a plurality of sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, the method comprising the steps of:

(a) providing a fire signal to nozzles at a fust and nth position in each set of nozzles;
(b) providing a fire signal to the next inward pair of nozzles in each set;

(c) in the event n is an even number, repeating step (b) until all of the nozzles in each set has been fired; and (d) in the event n is an odd number, repeating step (b) until all of the nozzles but a central nozzle in each set have been fired, and then firing the central nozzle.

Optionally the printer is manufactured in accordance with a method of manufacturing a plurality of printhead modules, at least some of which are capable of being combined in pairs to form bilithic pagewidth printheads, the method comprising the step of laying out each of the plurality of printhead modules on a wafer substrate, wherein at least one of the printhead modules is right-handed and at least another is left-handed.

Optionally the printer includes a printhead module including:
at least one row of print nozzles;

at least two shift registers for shifting in dot data supplied from a data source to each of the at least one rows, wherein each print nozzle obtains dot data to be fired from an element of one of the shift registers.

Optionally the printer includes:

a printhead comprising at least a first elongate printhead module, the at least one printhead module including at least one row of print nozzles for expelling ink; and at least first and second printer controllers configured to receive print data and process the print data to output dot data to the printhead, wherein the first and second printer controllers are connected to a common input of the printhead.

Optionally the printer includes:

a printhead comprising first and second elongate printhead modules, the printhead modules being parallel to each other and being disposed end to end on either side of a join region;

at least first and second printer controllers configured to receive print data and process the print data to output dot data to the printhead, wherein the fust printer controller outputs dot data only to the first printhead module and the second printer controller outputs dot data only to the second printhead module, wherein the printhead modules are configured such that no dot data passes between them.

Optionally the printer includes:

5 a printhead comprising first and second elongate printhead modules, the printhead modules being parallel to each other and being disposed end to end on either side of a join region, wherein the first printhead module is longer than the second printhead module;

at least first and second printer controllers configured to receive print data and process the print data to output dot data for the printhead, wherein: the first printer controller outputs dot data to both the first printhead 10 module and the second controller; and the second printer controller outputs dot data to the second printhead module, wherein the dot data output by the second printer controller includes dot data it generates and at least some of the dot data received from the fust printer controller.

Optionally the printer includes at least one printhead module, configured for at least partially compensating for 15 errors in ink dot placement by at least one of a plurality of nozzles on the printhead module due to erroneous rotational displacement of the printhead module relative to a carrier, the printer being configured to:

access a correction factor associated with the at least one printhead module;

determine an order in which at least some of the dot data is supplied to at least one of the at least one printhead modules, the order being determined at least partly on the basis of the correction factor, thereby to at 20 least partially compensate for the rotational displacement and supply the dot data to the printhead module.

Optionally the printer includes a printhead module having a plurality of nozzles for expelling ink, the printhead module including a plurality of thermal sensors, each of the thermal sensors being configured to respond to a 25 temperature at or adjacent at least one of the nozzles, the printer being configured to modify operation of at least some of the nozzles in response to the temperature rising above a first threshold.

Optionally the printer controls a printhead comprising at least one monolithic printhead module, the at least one printhead module having a plurality of rows of nozzles configured to extend, in use, across at least part of a 30 printable pagewidth of the printhead, the nozzles in each row being grouped into at least first and second fire groups, the printhead module being configured to sequentially fire, for each row, the nozzles of each fire group, such that each nozzle in the sequence from each fire group is fired simultaneously with respective corresponding nozzles in the sequence in the other fire groups, wherein the nozzles are fired row by row such that the nozzles of each row are all fired before the nozzles of each subsequent row, wherein the printer controller is configured to provide one or more control signals that control the order of firing of the nozzles.

Optionally the printer includes a printer controller for sending to a printhead:
dot data to be printed with at least two different inks; and control data for controlling printing of the dot data;

the printer controller including at least one communication output, each or the communication output being configured to output at least some of the control data and at least some of the dot data for the at least two inks.

Optionally the printer includes a printer controller for supplying data to a printhead module including at least one row of printhead nozzles, at least one row including at least one displaced row portion, the displacement of the row portion including a component in a direction normal to that of a pagewidth to be printed.

Optionally the printer includes a printer controller for supplying print data to at least one printhead module capable of printing a maximum of n of channels of print data, the at least one ptinthead module being configurable into:

a first mode, in which the printhead module is configured to receive data for a first number of the channels; and a second mode, in which the printhead module is configured to receive print data for a second number of the channels, wherein the first number is greater than the second number;

wherein the printer controller is selectively configurable to supply dot data for the first and second modes.
Optionally the printer includes a printer controller for supplying data to a printhead comprising a plurality of printhead modules, the printhead being wider than a reticle step used in forming the modules, the printhead comprising at least two types of the modules, wherein each type is determined by its geometric shape in plan.
Optionally the printer includes a printer controller for supplying one or more control signals to a printhead module, the printhead module including at least one row that comprises a plurality of sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, such that:

(a) a fire signal is provided to nozzles at a first and nth position in each set of nozzles;

(b) a fire signal is provided to the next inward pair of nozzles in each set;

(c) in the event n is an even number, step (b) is repeated until all of the nozzles in each set has been fired;
and (d) in the event n is an odd number, step (b) is repeated until all of the nozzles but a central nozzle in each set have been fired, and then the central nozzle is fired.

Optionally the printer includes a printer controller for supplying one or more control signals to a printhead module, the printhead module including at least one row that comprises a plurality of adjacent sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, the method comprising providing, for each set of nozzles, a fire signal in accordance with the sequence: [nozzle position 1, nozzle position n, nozzle position 2, nozzle position (n-1), ... , nozzle position x], wherein nozzle position x is at or adjacent the centre of the set of nozzles.

Optionally the printer includes a printer controller for supplying dot data to a printhead module comprising at least first and second rows configured to print ink of a similar type or color, at least some nozzles in the first row being aligned with respective corresponding nozzles in the second row in a direction of intended media travel relative to the printhead, the printhead module being configurable such that the nozzles in the fust and second pairs of rows are fired such that some dots output to print media are printed to by nozzles from the first pair of rows and at least some other dots output to print media are printed to by nozzles from the second pair of rows, the printer controller being configurable to supply dot data to the printhead module for printing.

Optionally the printer includes a printer controller for supplying dot data to at least one printhead module, the at least one printhead module comprising a plurality of rows, each of the rows comprising a plurality of nozzles for ejecting ink, wherein the printhead module includes at least first and second rows configured to print ink of a similar type or color, the printer controller being configured to supply the dot data to the at least one printhead module such that, in the event a nozzle in the first row is faulty, a corresponding nozzle in the second row prints an ink dot at a position on print media at or adjacent a position where the faulty nozzle would otherwise have printed it.

Optionally the printer includes a printer controller for receiving first data and manipulating the first data to produce dot data to be printed, the print controller including at least two serial outputs for supplying the dot data to at least one printhead.

Optionally the printer includes a printer controller for supplying data to a printhead module including:

at least one row of print nozzles;

at least first and second shift registers for shifting in dot data supplied from a data source, wherein each shift register feeds dot data to a group of nozzles, and wherein each of the groups of the nozzles is interleaved with at least one of the other groups of the nozzles.

Optionally the printer includes a printer controller for supplying data to a printhead capable of printing a maximum of n of channels of print data, the printhead being configurable into:

a first mode, in which the printhead is configured to receive print data for a first number of the channels;
and a second mode, in which the printhead is configured to receive print data for a second number of the channels, wherein the first number is greater than the second number.

Optionally the printer includes a printer controller for supplying data to a printhead comprising a plurality of printhead modules, the printhead being wider than a reticle step used in forming the modules, the printhead comprising at least two types of the modules, wherein each type is determined by its geometric shape in plan.
Optionally the printer includes a printer controller for supplying data to a printhead module including at least one row that comprises a plurality of sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, such that, for each set of nozzles, a fire signal is provided in accordance with the sequence: [nozzle position 1, nozzle position n, nozzle position 2, nozzle position (n-1), ... , nozzle position x], wherein nozzle position x is at or adjacent the centre of the set of nozzles.

Optionally the printer includes a printer controller for supplying data to a printhead module including at least one row that comprises a plurality of adjacent sets of n adjacent nozzles, each of the nozzles being configured to expel the ink in response to a fire signal, the printhead being configured to output ink from nozzles at a first and nth position in each set of nozzles, and then each next inward pair of nozzles in each set, until:

in the event n is an even number, all of the nozzles in each set has been fired; and in the event n is an odd number, all of the nozzles but a central nozzle in each set have been fired, and then to fire the central nozzle.

Optionally the printer includes a printer controller for supplying data to a printhead module for receiving dot data to be printed using at least two different inks and control data for controlling printing of the dot data, the printhead module including a communication input for receiving the dot data for the at least two colors and the control data.

Optionally the printer includes a printer controller for supplying data to a printhead module including at least one row of printhead nozzles, at least one row including at least one displaced row portion, the displacement of the row portion including a component in a direction normal to that of a pagewidth to be printed.

Optionally the printer includes a printer controller for supplying data to a printhead module having a plurality of rows of nozzles configured to extend, in use, across at least part of a printable pagewidth, the nozzles in each row being grouped into at least first and second fire groups, the printhead module being configured to sequentially fire, for each row, the nozzles of each fire group, such that each nozzle in the sequence from each fire group is fired simultaneously with respective corresponding nozzles in the sequence in the other fire groups, wherein the nozzles are fired row by row such that the nozzles of each row are all fired before the nozzles of each subsequent row.
Optionally the printer includes a printer controller for supplying data to a printhead module comprising at least first and second rows configured to print ink of a similar type or color, at least some nozzles in the first row being aligned with respective corresponding nozzles in the second row in a direction of intended media travel relative to the printhead, the printhead module being configurable such that the nozzles in the first and second pairs of rows are fired such that some dots output to print media are printed to by nozzles from the first pair of rows and at least some other dots output to print media are printed to by nozzles from the second pair of rows.

Optionally the printer includes a printer controller for providing data to a printhead module that includes:
at least one row of print nozzles;

at least first and second shift registers for shifting in dot data supplied from a data source, wherein each shift register feeds dot data to a group of nozzles, and wherein each of the groups of the nozzles is interleaved with at least one of the other groups of the nozzles.

Optionally the printer includes a printer controller for supplying data to a printhead module having a plurality of nozzles for expelling ink, the printhead module including a plurality of thermal sensors, each of the thermal sensors being configured to respond to a temperature at or adjacent at least one of the nozzles, the printhead module being configured to modify operation of the nozzles in response to the temperature rising above a first threshold.

Optionally the printer includes a printer controller for supplying data to a printhead module comprising a plurality 5 of rows, each of the rows comprising a plurality of nozzles for ejecting ink, wherein the printhead module includes at least first and second rows configured to print ink of a similar type or color, and being configured such that, in the event a nozzle in the first row is faulty, a corresponding nozzle in the second row prints an ink dot at a position on print media at or adjacent a position where the faulty nozzle would otherwise have printed it.

10 In a ninth aspect the present invention provides a printer comprising:

a printhead comprising first and second elongate printhead modules, the printhead modules being parallel to each other and being disposed end to end on either side of a join region, wherein the first printhead module is longer than the second printhead module;

at least first and second printer controllers configured to receive print data and process the print data to 15 output dot data for the printhead, wherein: the first printer controller outputs dot data to both the first printhead module and the second controller; and the second printer controller outputs dot data to the second printhead module, wherein the dot data output by the second printer controller includes dot data it generates and at least some of the dot data received from the first printer controller.

20 Optionally the printhead modules are configured such that no dot data passes between them.

Optionally the printer includes at least one synchronization means between the first and second printer controllers for synchronizing the supply of dot data by the printer controllers.

25 Optionally each of the printer controllers is configurable to supply the dot data to printhead modules of a plurality of different lengths.

Optionally the printhead is a pagewidth printhead.

30 In a further aspect the present invention provides a print engine comprising:
a carrier;

a printhead comprising first and second elongate printhead modules, the printhead modules being mounted parallel to each other end to end on the carrier on either side of a join region, wherein the first printhead module is longer than the second printhead module;

at least first and second printer controllers configured to receive print data and process the print data to output dot data for the printhead, wherein: the first printer controller outputs dot data to both the first printhead module and the second controller; and the second printer controller outputs dot data to the second printhead module, wherein the dot data output by the second printer controller includes dot data it generates and at least some of the dot data received from the first printer controller.

Optionally the printhead modules are configured such that no dot data passes between them.

Optionally the print engine includes at least one synchronization means between the first and second printer controllers for synchronizing the supply of dot by the printer controllers.

Optionally each of the printer controllers is configurable to supply the dot data to printhead modules of a plurality of different lengths.

Optionally the printhead is a pagewidth printhead.

Optionally the printer controller is for implementing a method of at least partially compensating for errors in ink dot placement by at least one of a plurality of nozzles due to erroneous rotational displacement of a printhead module relative to a carrier, the nozzles being disposed on the printhead module, the method comprising the steps of:

(a) determining the rotational displacement;

(b) determining at least one correction factor that at least partially compensates for the ink dot displacement;
and (c) using the correction factor to alter the output of the ink dots to at least partially compensate for the rotational displacement.

Optionally the printer controller is for implementing a method of expelling ink from a printhead module including at least one row that comprises a plurality of adjacent sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, the method comprising providing, for each set of nozzles, a fire signal in accordance with the sequence: [nozzle position 1, nozzle position n, nozzle position 2, nozzle position (n-1), ... , nozzle position x], wherein nozzle position x is at or adjacent the centre of the set of nozzles.

Optionally the printer controller is for implementing a method of expelling ink from a printhead module including at least one row that comprises a plurality of sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, the method comprising the steps of:

(a) providing a fire signal to nozzles at a first and nth position in each set of nozzles;
(b) providing a fire signal to the next inward pair of nozzles in each set;

(c) in the event n is an even number, repeating step (b) until all of the nozzles in each set has been fired; and (d) in the event n is an odd number, repeating step (b) until all of the nozzles but a central nozzle in each set have been fired, and then firing the central nozzle.

Optionally the printer controller is manufactured in accordance with a method of manufacturing a plurality of printhead modules, at least some of which are capable of being combined in pairs to form bilithic pagewidth printheads, the method comprising the step of laying out each of the plurality of printhead modules on a wafer substrate, wherein at least one of the printhead modules is right-handed and at least another is left-handed.
Optionally the printer controller supplies data to a printhead module including:

at least one row of print nozzles;

at least two shift registers for shifting in dot data supplied from a data source to each of the at least one rows, wherein each print nozzle obtains dot data to be fired from an element of one of the shift registers.
Optionally the printer controller is installed in a printer comprising:

a printhead comprising at least a first elongate printhead module, the at least one printhead module including at least one row of print nozzles for expelling ink; and at least first and second printer controllers configured to receive print data and process the print data to output dot data to the printhead, wherein the first and second printer controllers are connected to a common input of the printhead.

Optionally the printer controller is installed in a printer comprising:

a printhead comprising first and second elongate printhead modules, the printhead modules being parallel to each other and being disposed end to end on either side of a join region;

at least first and second printer controllers configured to receive print data and process the print data to output dot data to the printhead, wherein the first printer controller outputs dot data only to the first printhead module and the second printer controller outputs dot data only to the second printhead module, wherein the printhead modules are configured such that no dot data passes between them.

Optionally the printer controller is installed in a printer comprising:

a printhead comprising first and second elongate printhead modules, the printhead modules being parallel to each other and being disposed end to end on either side of a join region, wherein the first printhead module is longer than the second printhead module;

at least first and second printer controllers configured to receive print data and process the print data to output dot data to the printhead, wherein: the first printer controller outputs dot data to both the fnst printhead module and the second printhead module; and the second printer controller outputs dot data only to the second printhead module.

Optionally the printer controller supplies dot data to at least one printhead module and at least partially compensating for errors in ink dot placement by at least one of a plurality of nozzles on the printhead module due to erroneous rotational displacement of the printhead module relative to a carrier, the printer being configured to:

access a correction factor associated with the at least one printhead module;

detenmine an order in which at least some of the dot data is supplied to at least one of the at least one printhead modules, the order being detennined at least partly on the basis of the correction factor, thereby to at least partially compensate for the rotational displacement; and supply the dot data to the printhead module.

Optionally the printer controller supplies dot data to a printhead module having a plurality of nozzles for expelling ink, the printhead module including a plurality of thermal sensors, each of the thermal sensors being configured to respond to a temperature at or adjacent at least one of the nozzles, the printer controller being configured to modify operation of at least some of the nozzles in response to the temperature rising above a first threshold.

Optionally the printer controller controls a printhead comprising at least one monolithic printhead module, the at least one printhead module having a plurality of rows of nozzles configured to extend, in use, across at least part of a printable pagewidth of the printhead, the nozzles in each row being grouped into at least first and second fire groups, the printhead module being configured to sequentially fire, for each row, the nozzles of each fire group, such that each nozzle in the sequence from each fire group is fired simultaneously with respective corresponding nozzles in the sequence in the other fire groups, wherein the nozzles are fired row by row such that the nozzles of each row are all fired before the nozzles of each subsequent row, wherein the printer controller is configured to provide one or more control signals that control the order of firing of the nozzles.

Optionally the printer controller outputs to a printhead module:
dot data to be printed with at least two different inks; and control data for controlling printing of the dot data;

the printer controller including at least one communication output, each or the communication output being configured to output at least some of the control data and at least some of the dot data for the at least two inks.

Optionally the printer controller supplies data to a printhead module including at least one row of printhead nozzles, at least one row including at least one displaced row portion, the displacement of the row portion including a component in a direction normal to that of a pagewidth to be printed.

Optionally the printer controller supplies print data to at least one printhead module capable of printing a maximum of n of channels of print data, the at least one printhead module being configurable into:

a first mode, in which the printhead module is configured to receive data for a first number of the channels; and a second mode, in which the printhead module is configured to receive print data for a second number of the channels, wherein the first number is greater than the second number;

wherein the printer controller is selectively configurable to supply dot data for the first and second modes.
Optionally the printer controller supplies data to a printhead comprising a plurality of printhead modules, the printhead being wider than a reticle step used in forming the modules, the printhead comprising at least two types of the modules, wherein each type is determined by its geometric shape in plan.

Optionally the printer controller supplies one or more control signals to a printhead module, the printhead module including at least one row that comprises a plurality of sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, such that:

(a) a fire signal is provided to nozzles at a first and nth position in each set of nozzles;
5 (b) a fire signal is provided to the next inward pair of nozzles in each set;

(c) in the event n is an even number, step (b) is repeated until all of the nozzles in each set has been fired;
and (d) in the event n is an odd number, step (b) is repeated until all of the nozzles but a central nozzle in each set have been fired, and then the central nozzle is fired.

Optionally the printer controller supplies one or more control signals to a printhead module, the printhead module including at least one row that comprises a plurality of adjacent sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, the method comprising providing, for each set of nozzles, a fire signal in accordance with the sequence: [nozzle position 1, nozzle position n, nozzle position 2, nozzle position (n-1), ... , nozzle position x], wherein nozzle position x is at or adjacent the centre of the set of nozzles.

Optionally the printer controller supplies dot data to a printhead module comprising at least first and second rows configured to print ink of a similar type or color, at least some nozzles in the first row being aligned with respective corresponding nozzles in the second row in a direction of intended media travel relative to the printhead, the printhead module being configurable such that the nozzles in the first and second pairs of rows are fired such that some dots output to print media are printed to by nozzles from the first pair of rows and at least some other dots output to print media are printed to by nozzles from the second pair of rows, the printer controller being configurable to supply dot data to the printhead module for printing.

Optionally the printer controller supplies dot data to at least one printhead module, the at least one pr'inthead module comprising a plurality of rows, each of the rows comprising a plurality of nozzles for ejecting ink, wherein the printhead module includes at least first and second rows configured to print ink of a similar type or color, the printer controller being configured to supply the dot data to the at least one printhead module such that, in the event a nozzle in the first row is faulty, a corresponding nozzle in the second row prints an ink dot at a position on print media at or adjacent a position where the faulty nozzle would otherwise have printed it.

Optionally the printer controller receives first data and manipulating the first data to produce dot data to be printed, the print controller including at least two serial outputs for supplying the dot data to at least one printhead.
Optionally the printer controller supplies data to a printhead module including:

at least one row of print nozzles;

at least first and second shift registers for shifting in dot data supplied from a data source, wherein each shift register feeds dot data to a group of nozzles, and wherein each of the groups of the nozzles is interleaved with at least one of the other groups of the nozzles.

Optionally the printer controller supplies data to a printhead capable of printing a maximum of n of channels of print data, the printhead being configurable into:

a first mode, in which the printhead is configured to receive print data for a first number of the channels;
and a second mode, in which the printhead is configured to receive print data for a second number of the channels, wherein the first number is greater than the second number.

Optionally the printer controller supplies data to a printhead comprising a plurality of printhead modules, the printhead being wider than a reticle step used in forming the modules, the printhead comprising at least two types of the modules, wherein each type is determined by its geometric shape in plan.

Optionally the printer controller supplies data to a printhead module including at least one row that comprises a plurality of sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, such that, for each set of nozzles, a fire signal is provided in accordance with the sequence: [nozzle position 1, nozzle position n, nozzle position 2, nozzle position (n-1), ... , nozzle position x], wherein nozzle position x is at or adjacent the centre of the set of nozzles.

Optionally the printer controller supplies data to a printhead module including at least one row that comprises a plurality of adjacent sets of n adjacent nozzles, each of the nozzles being configured to expel the ink in response to a fire signal, the printhead being configured to output ink from nozzles at a first and nth position in each set of nozzles, and then each next inward pair of nozzles in each set, until:

in the event n is an even number, all of the nozzles in each set has been fired; and in the event n is an odd number, all of the nozzles but a central nozzle in each set have been fired, and then to fire the central nozzle.

Optionally the printer controller supplies data to a printhead module for receiving dot data to be printed using at least two different inks and control data for controlling printing of the dot data, the printhead module including a communication input for receiving the dot data for the at least two colors and the control data.

Optionally the printer controller supplies data to a printhead module including at least one row of printhead nozzles, at least one row including at least one displaced row portion, the displacement of the row portion including a component in a direction normal to that of a pagewidth to be printed.

Optionally the printer controller supplies data to a printhead module having a plurality of rows of nozzles configured to extend, in use, across at least part of a printable pagewidth, the nozzles in each row being grouped into at least first and second fire groups, the printhead module being configured to sequentially fire, for each row, the nozzles of each fire group, such that each nozzle in the sequence from each fire group is fired simultaneously with respective corresponding nozzles in the sequence in the other fire groups, wherein the nozzles are fired row by row such that the nozzles of each row are all fired before the nozzles of each subsequent row.

Optionally the printer controller supplies data to a printhead module comprising at least first and second rows configured to print ink of a similar type or color, at least some nozzles in the first row being aligned with respective corresponding nozzles in the second row in a direction of intended media travel relative to the printhead, the printhead module being configurable such that the nozzles in the first and second pairs of rows are fired such that some dots output to print media are printed to by nozzles from the fu-st pair of rows and at least some other dots output to print media are printed to by nozzles from the second pair of rows.

Optionally the printer controller supplies data to a printhead module that includes:
at least one row of print nozzles;

at least first and second shift registers for shifting in dot data supplied from a data source, wherein each shift register feeds dot data to a group of nozzles, and wherein each of the groups of the nozzles is interleaved with at least one of the other groups of the nozzles.

Optionally the printer controller supplies data to a printhead module having a plurality of nozzles for expelling ink, the printhead module including a plurality of thermal sensors, each of the thermal sensors being configured to respond to a temperature at or adjacent at least one of the nozzles, the printhead module being configured to modify operation of the nozzles in response to the temperature rising above a first threshold.

Optionally the printer controller supplies data to a printhead module comprising a plurality of rows, each of the rows comprising a plurality of nozzles for ejecting ink, wherein the printhead module includes at least first and second rows configured to print ink of a similar type or color, and being configured such that, in the event a nozzle in the first row is faulty, a corresponding nozzle in the second row prints an ink dot at a position on print media at or adjacent a position where the faulty nozzle would otherwise have printed it.

In a tenth aspect the present invention provides printer controller for supplying dot data to at least one printhead module and at least partially compensating for errors in ink dot placement by at least one of a plurality of nozzles on the printhead module due to erroneous rotational displacement of the printhead module relative to a carrier, the printer being configured to:

access a correction factor associated with the at least one printhead module;

determine an order in which at least some of the dot data is supplied to at least one of the at least one printhead modules, the order being detennined at least partly on the basis of the correction factor, thereby to at least partially compensate for the rotational displacement; and supply the dot data to the printhead module.

Optionally, the nozzles are disposed in a plurality of rows, and the printer controller is configured to reallocate at least one of the ink dots from at least one original print line to at least one alternate print line, thereby to effect the at least partial compensation.

Optionally the printer controller is configured to retrieve the correction factor from a memory associated with the printhead.

Optionally, the memory is mounted with the printhead, the printhead being mounted on the print engine.

Optionally, the rotational displacement is roll.

Optionally, the rotational displacement is yaw.

Optionally, the printhead module being one of a plurality of printhead modules mounted on a carrier to foim a printhead and the en or in ink dot placement being an error relative to ink dots output by one or more of the other printhead modules Optionally, the printhead module is part of a printhead comprising a plurality of the modules, the printer controller being configured to determine an order in which at least some of the dot data is supplied to a plurality of the printhead modules, the order being determined at least partly on the basis of one or more of the correction factors, thereby to at least partially compensate for the rotational displacement of the plurality of the printheads.
Optionally, the correction factor is at least partially based on a thickness of media being printed on.

Optionally the printer controller configured to at least improve first order continuity between ink dots printed by adjacent printhead modules.

Optionally a print engine including the print controller according and a plurality of the printhead modules that define a printhead, the print engine being configured to compensate for the rotational displacement of at least one of the printhead modules.

Optionally the print engine further including a memory for storing the correction factor in a form accessible to the printer controller.

Optionally the print engine is configured to alter a timing of fire signals supplied to at least one of the nozzles on the basis of the correction factor, thereby to further effect the at least partial compensation.

Optionally the print engine is configured to supply the altered fire signals are to both reallocated ink dots and non-reallocated ink dots.

Optionally the printhead is a pagewidth printhead.

Optional a printer including a printer controller for supplying dot data to at least one printhead module and at least partially compensating for errors in ink dot placement by at least one of a plurality of nozzles on the printhead 5 module due to erroneous rotational displacement of the printhead module relative to a carrier, the printer being configured to:

access a correction factor associated with the at least one printhead module;

determine an order in which at least some of the dot data is supplied to at least one of the at least one printhead modules, the order being determined at least partly on the basis of the correction factor, thereby to at 10 least partially compensate for the rotational displacement; and supply the dot data to the printhead module.

Optionally the printer further including a pagewidth printhead comprising a plurality of the printhead modules.
15 Optionally the printer controller is for implementing a method of at least partially compensating for errors in ink dot placement by at least one of a plurality of nozzles due to erroneous rotational displacement of a printhead module relative to a carrier, the nozzles being disposed on the printhead module, the method comprising the steps of:

(a) determining the rotational displacement;

20 (b) determining at least one correction factor that at least partially compensates for the ink dot displacement;
and (c) using the correction factor to alter the output of the ink dots to at least partially compensate for the rotational displacement.

25 Optionally the printer controller is for implementing a method of expelling ink from a printhead module including at least one row that comprises a plurality of adjacent sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, the method comprising providing, for each set of nozzles, a fire signal in accordance with the sequence: [nozzle position 1, nozzle position n, nozzle position 2, nozzle position (n-1), ... , nozzle position x], wherein nozzle position x is at or adjacent the centre of the set of nozzles.

Optionally the printer controller is for implementing a method of expelling ink from a printhead module including at least one row that comprises a plurality of sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, the method comprising the steps of:

(a) providing a fire signal to nozzles at a first and nth position in each set of nozzles;
(b) providing a fire signal to the next inward pair of nozzles in each set;

(c) in the event n is an even number, repeating step (b) until all of the nozzles in each set has been fired; and (d) in the event n is an odd number, repeating step (b) until all of the nozzles but a central nozzle in each set have been fired, and then firing the central nozzle.

Optionally the printer controller is manufactured in accordance with a method of manufacturing a plurality of printhead modules, at least some of which are capable of being combined in pairs to form bilithic pagewidth printheads, the method comprising the step of laying out each of the plurality of printhead modules on a wafer substrate, wherein at least one of the printhead modules is right-handed and at least another is left-handed.

Optionally the printer controller for supplying data to a printhead module including:
at least one row of print nozzles;

at least two shift registers for shifting in dot data supplied from a data source to each of the at least one rows, wherein each print nozzle obtains dot data to be fired from an element of one of the shift registers.

Optionally the printer controller is installed in a printer comprising:

a printhead comprising at least a first elongate printhead module, the at least one printhead module including at least one row of print nozzles for expelling ink; and at least first and second printer controllers configured to receive print data and process the print data to output dot data to the printhead, wherein the first and second printer controllers are connected to a common input of the printhead.

Optionally the printer controller installed in a printer comprising:

a printhead comprising first and second elongate printhead modules, the printhead modules being parallel to each other and being disposed end to end on either side of a join region;

at least first and second printer controllers configured to receive print data and process the print data to output dot data to the printhead, wherein the first printer controller outputs dot data only to the first printhead module and the second printer controller outputs dot data only to the second printhead module, wherein the printhead modules are configured such that no dot data passes between them.

Optionally the printer controller installed in a printer comprising:

a printhead comprising first and second elongate printhead modules, the printhead modules being parallel to each other and being disposed end to end on either side of a join region, wherein the first printhead module is longer than the second printhead module;

at least first and second printer controllers configured to receive print data and process the print data to output dot data to the printhead, wherein: the first printer controller outputs dot data to both the first printhead module and the second printhead module; and the second printer controller outputs dot data only to the second printhead module.

Optionally the printer controller installed in a printer comprising:

a printhead comprising first and second elongate printhead modules, the printhead modules being parallel to each other and being disposed end to end on either side of a join region, wherein the first printhead module is longer than the second printhead module;

at least first and second printer controllers configured to receive print data and process the print data to output dot data for the printhead, wherein: the first printer controller outputs dot data to both the first printhead module and the second controller; and the second printer controller outputs dot data to the second printhead module, wherein the dot data output by the second printer controller includes dot data it generates and at least some of the dot data received from the first printer controller.

Optionally the printer controller supplies dot data to a printhead module having a plurality of nozzles for expelling ink, the printhead module including a plurality of thermal sensors, each of the thermal sensors being configured to respond to a temperature at or adjacent at least one of the nozzles, the printer controller being configured to modify operation of at least some of the nozzles in response to the temperature rising above a first threshold.
Optionally the printer controller controls a printhead comprising at least one monolithic printhead module, the at least one printhead module having a plurality of rows of nozzles configured to extend, in use, across at least part of a printable pagewidth of the printhead, the nozzles in each row being grouped into at least first and second fire groups, the printhead module being configured to sequen6ally fire, for each row, the nozzles of each fire group, such that each nozzle in the sequence from each fire group is fired simultaneously with respective corresponding nozzles in the sequence in the other fire groups, wherein the nozzles are fired row by row such that the nozzles of each row are all fired before the nozzles of each subsequent row, wherein the printer controller is configured to provide one or more control signals that control the order of firing of the nozzles.

Optionally the printer controller outputs to a printhead module:

dot data to be printed with at least two different inks; and control data for controlling printing of the dot data;

the printer controller including at least one communication output, each or the conununication output being configured to output at least some of the control data and at least some of the dot data for the at least two inks.

Optionally the printer controller supplies data to a printhead module including at least one row of printhead nozzles, at least one row including at least one displaced row portion, the displacement of the row portion including a component in a direction normal to that of a pagewidth to be printed.

Optionally the printer controller supplies data to at least one printhead module capable of printing a maximum of n of channels of print data, the at least one printhead module being configurable into:

a first mode, in which the printhead module is configured to receive data for a first number of the channels; and a second mode, in which the printhead module is configured to receive print data for a second number of the channels, wherein the first number is greater than the second number;

wherein the printer controller is selectively configurable to supply dot data for the first and second modes.
Optionally the printer controller supplies data to a printhead comprising a plurality of printhead modules, the printhead being wider than a reticle step used in forming the modules, the printhead comprising at least two types of the modules, wherein each type is determined by its geometric shape in plan.

Optionally the printer controller supplies one or more control signals to a printhead module, the printhead module including at least one row that comprises a plurality of sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, such that:

(a) a fire signal is provided to nozzles at a first and nth position in each set of nozzles;
(b) a fire signal is provided to the next inward pair of nozzles in each set;

(c) in the event n is an even number, step (b) is repeated until all of the nozzles in each set has been fired;
and (d) in the event n is an odd number, step (b) is repeated until all of the nozzles but a central nozzle in each set have been fired, and then the central nozzle is fired.

Optionally the printer controller supplies one or more control signals to a printhead module, the printhead module including at least one row that comprises a plurality of adjacent sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, the method comprising providing, for each set of nozzles, a fire signal in accordance with the sequence: [nozzle position 1, nozzle position n, nozzle position 2, nozzle position (n-1), ... , nozzle position x], wherein nozzle position x is at or adjacent the centre of the set of nozzles.

Optionally the printer controller supplies dot data to a printhead module comprising at least first and second rows configured to print ink of a similar type or color, at least some nozzles in the first row being aligned with respective corresponding nozzles in the second row in a direction of intended media travel relative to the printhead, the printhead module being configurable such that the nozzles in the first and second pairs of rows are fired such that some dots output to print media are printed to by nozzles from the first pair of rows and at least some other dots output to print media are printed to by nozzles from the second pair of rows, the printer controller being configurable to supply dot data to the printhead module for printing.

Optionally the printer controller supplies dot data to at least one printhead module, the at least one printhead module comprising a plurality of rows, each of the rows comprising a plurality of nozzles for ejecting ink, wherein the printhead module includes at least first and second rows configured to print ink of a similar type or color, the printer controller being configured to supply the dot data to the at least one printhead module such that, in the event a nozzle in the first row is faulty, a corresponding nozzle in the second row prints an ink dot at a position on print media at or adjacent a position where the faulty nozzle would otherwise have printed it.
Optionally the printer controller receives first data and manipulates the first data to produce dot data to be printed, the print controller including at least two serial outputs for supplying the dot data to at least one printhead.

Optionally the printer controller supplies data to a printhead module including:
at least one row of print nozzles;

at least first and second shift registers for shifting in dot data supplied from a data source, wherein each shift register feeds dot data to a group of nozzles, and wherein each of the groups of the nozzles is interleaved with at least one of the other groups of the nozzles.

5 Optionally the printer controller supplies data to a printhead capable of printing a maximum of n of channels of print data, the printhead being configurable into:

a first mode, in which the printhead is configured to receive print data for a first number of the channels;
and a second mode, in which the printhead is configured to receive print data for a second number of the 10 channels, wherein the first number is greater than the second number.

Optionally the printer controller supplies data to a printhead comprising a plurality of printhead modules, the printhead being wider than a reticle step used in forming the modules, the printhead comprising at least two types of the modules, wherein each type is determined by its geometric shape in plan.

Optionally the printer controller supplies data to a printhead module including at least one row that comprises a plurality of sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, such that, for each set of nozzles, a fire signal is provided in accordance with the sequence: [nozzle position 1, nozzle position n, nozzle position 2, nozzle position (n-1), ... , nozzle position x], wherein nozzle position x is at or adjacent the centre of the set of nozzles.

Optionally the printer controller supplies data to a printhead module including at least one row that comprises a plurality of adjacent sets of n adjacent nozzles, each of the nozzles being configured to expel the ink in response to a fire signal, the printhead being configured to output ink from nozzles at a first and nth position in each set of nozzles, and then each next inward pair of nozzles in each set, until:

in the event n is an even number, all of the nozzles in each set has been fired; and in the event n is an odd number, all of the nozzles but a central nozzle in each set have been fired, and then to fire the central nozzle.

Optionally the printer controller supplies data to a printhead module for receiving dot data to be printed using at least two different inks and control data for controlling printing of the dot data, the printhead module including a communication input for receiving the dot data for the at least two colors and the control data.

Optionally the printer controller supplies data to a printhead module including at least one row of printhead nozzles, at least one row including at least one displaced row portion, the displacement of the row portion including a component in a direction normal to that of a pagewidth to be printed.

Optionally the printer controller supplies data to a printhead module having a plurality of rows of nozzles configured to extend, in use, across at least part of a printable pagewidth, the nozzles in each row being grouped into at least first and second fire groups, the printhead module being configured to sequentially fire, for each row, the nozzles of each fire group, such that each nozzle in the sequence from each fire group is fired simultaneously with respective corresponding nozzles in the sequence in the other fire groups, wherein the nozzles are fired row by row such that the nozzles of each row are all fired before the nozzles of each subsequent row.

Optionally the printer controller supplies data to a printhead module comprising at least first and second rows configured to print ink of a similar type or color, at least some nozzles in the first row being aligned with respective corresponding nozzles in the second row in a direction of intended media travel relative to the printhead, the printhead module being configurable such that the nozzles in the first and second pairs of rows are fired such that some dots output to print media are printed to by nozzles from the first pair of rows and at least some other dots output to print media are printed to by nozzles from the second pair of rows.

Optionally the printer controller supplies data to a printhead module that includes:
at least one row of print nozzles;

at least first and second shift registers for shifting in dot data supplied from a data source, wherein each shift register feeds dot data to a group of nozzles, and wherein each of the groups of the nozzles is interleaved with at least one of the other groups of the nozzles.

Optionally the printer controller supplies data to a printhead module having a plurality of nozzles for expelling ink, the printhead module including a plurality of thennal sensors, each of the thermal sensors being configured to respond to a temperature at or adjacent at least one of the nozzles, the printhead module being configured to modify operation of the nozzles in response to the temperature rising above a first threshold.

Optionally the printer controller supplies data to a printhead module comprising a plurality of rows, each of the rows comprising a plurality of nozzles for ejecting ink, wherein the printhead module includes at least first and second rows configured to print ink of a similar type or color, and being configured such that, in the event a nozzle in the first row is faulty, a corresponding nozzle in the second row prints an ink dot at a position on print media at or adjacent a position where the faulty nozzle would otherwise have printed it.

In an eleventh aspect the present invention provides printer controller for supplying dot data to a printhead module having a plurality of nozzles for expelling ink, the printhead module including a plurality of thermal sensors, each of the thermal sensors being configured to respond to a temperature at or adjacent at least one of the nozzles, the printer controller being configured to modify operation of at least some of the nozzles in response to the temperature rising above a first threshold.

Optionally the printer controller is configured to modify the operation of the nozzles at or adjacent the at least one thermal sensor, such that operation of nozzles not at or adjacent the at least one thermal sensor is not modified.
Optionally each thermal sensor is associated with a predetermined group of the nozzles, the printer controller being configured to modify operation of the nozzles in the predetermined group for which the temperature has risen above the first threshold.

Optionally each thermal sensor is associated with a single nozzle.

Optionally the modification includes the printer controller preventing operation of the nozzle.

Optionally the modification includes the printer controller preventing operation of the nozzle for a predetermined period.

Optionally the modification includes the printer controller preventing operation of the nozzle until the temperature drops below a second threshold.

Optionally the second threshold is lower than the first threshold.
Optionally the second threshold is the same as the first threshold.

Optionally the temperature is not determined explicitly by the at least one thermal sensor or the module.
Optionally each of the nozzles including a thermal ink ejection mechanism.

Optionally the thennal sensor comprises at least part of one of the thermal inkjet mechanisms.
Optionally the thermal sensor comprises a heating element.

Optionally the thermal sensor determines the temperature by determining a resistance of the heating element.
Optionally the printer controller is configured to:

receive thermal information from the at least one thermal sensor;
determine the modification based on the thermal information; and send control information back to the printhead module, the control information being indicative of the modification to make to the operation of the one or more nozzles.

Optionally a print engine including a printer controller configured to:
receive thermal information from the at least one thermal sensor;
determine the modification based on the thermal information; and send control information back to the printhead module, the control information being indicative of the modification to make to the operation of the one or more nozzles; and a printhead module, wherein the printhead module further includes a plurality of data latches, the data latches being configured to provide dot data to respective ones of the nozzles, at least some of the data latches being configured to receive thermal signals from respective ones of the thermal sensors during an acquisition period.

Optionally the data latches are configured to form a shift register, the shift register being configured to:
shift the print data in during a print load phase;

sample the signals from the thermal sensors during a temperature load phase;
and shift the thermal signals out to the printer controller during an output phase.
Optionally the output phase coincides with a subsequent print load phase.

Optionally the print engine further includes logic circuitry configured to perform a bitwise operation on: each thermal signal as it is clocked out of the shift register; and each piece of dot data to be clocked into the shift register, such that when a thermal signal is indicative of a thermal problem with a nozzle, the logic circuitry prevents loading of data that would cause firing of that nozzle.

Optionally the logic circuitry includes an AND circuit that receives as inputs the dot data and the thermal signal corresponding to the nozzle for which the dot data is intended, an output of the AND circuit being in communication with an input of the shift register.

Optionally each thermal sensor is associated with a pair of the nozzles.

Optionally the printer controller is for implementing a method of at least partially compensating for errors in ink dot placement by at least one of a plurality of nozzles due to erroneous rotational displacement of a printhead module relative to a carrier, the nozzles being disposed on the printhead module, the method comprising the steps of:

(a) determining the rotational displacement;

(b) determining at least one correction factor that at least partially compensates for the ink dot displacement;
and (c) using the correction factor to alter the output of the ink dots to at least partially compensate for the rotational displacement.

Optionally the printer controller is for implementing a method of expelling ink from a printhead module including at least one row that comprises a plurality of adjacent sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, the method comprising providing, for each set of nozzles, a fire signal in accordance with the sequence: [nozzle position 1, nozzle position n, nozzle position 2, nozzle position (n-1), ... , nozzle position x], wherein nozzle position x is at or adjacent the centre of the set of nozzles.

Optionally the printer controller is for implementing a method of expelling ink from a printhead module including at least one row that comprises a plurality of sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, the method comprising the steps of:

5 (a) providing a fire signal to nozzles at a first and nth position in each set of nozzles;
(b) providing a fire signal to the next inward pair of nozzles in each set;

(c) in the event n is an even number, repeating step (b) until all of the nozzles in each set has been fired; and (d) in the event n is an odd number, repeating step (b) until all of the nozzles but a central nozzle in each set have been fired, and then firing the central nozzle.

Optionally the printer controller is manufactured in accordance with a method of manufacturing a plurality of printhead modules, at least some of which are capable of being combined in pairs to form bilithic pagewidth printheads, the method comprising the step of laying out each of the plurality of printhead modules on a wafer substrate, wherein at least one of the printhead modules is right-handed and at least another is left-handed.

Optionally the printer controller supplies data to a printhead module including:
at least one row of print nozzles;

at least two shift registers for shifting in dot data supplied from a data source to each of the at least one rows, wherein each print nozzle obtains dot data to be fired from an element of one of the shift registers.

Optionally the printer controller is installed in a printer comprising:

a printhead comprising at least a first elongate printhead module, the at least one printhead module including at least one row of print nozzles for expelling ink; and at least first and second printer controllers configured to receive print data and process the print data to output dot data to the printhead, wherein the first and second printer controllers are connected to a common input of the printhead.

Optionally the printer controller is installed in a printer comprising:

a printhead comprising first and second elongate printhead modules, the printhead modules being parallel to each other and being disposed end to end on either side of a join region;

at least first and second printer controllers configured to receive print data and process the print data to output dot data to the printhead, wherein the first printer controller outputs dot data only to the first printhead module and the second printer controller outputs dot data only to the second printhead module, wherein the printhead modules are configured such that no dot data passes between them.

Optionally the printer controller is installed in a printer comprising:

a printhead comprising first and second elongate printhead modules, the printhead modules being parallel to each other and being disposed end to end on either side of a join region, wherein the first printhead module is longer than the second printhead module;

at least first and second printer controllers configured to receive print data and process the print data to output dot data to the printhead, wherein: the first printer controller outputs dot data to both the first printhead module and the second printhead module; and the second printer controller outputs dot data only to the second printhead module.

Optionally the printer controller is installed in a printer comprising:

a printhead comprising first and second elongate printhead modules, the printhead modules being parallel to each other and being disposed end to end on either side of a join region, wherein the first printhead module is longer than the second printhead module;

at least first and second printer controllers configured to receive print data and process the print data to output dot data for the, printhead, wherein: the first p-inter controller outputs dot data to both the first printhead module and the second controller; and the second printer controller outputs dot data to the second printhead module, wherein the dot data output by the second printer controller includes dot data it generates and at least some of the dot data received from the first printer controller.

Optionally the printer controller supplies dot data to at least one printhead module and at least partially compensating for errors in ink dot placement by at least one of a plurality of nozzles on the printhead inodule due to erroneous rotational displacement of the printhead module relative to a carrier, the printer being configured to:
access a correction factor associated with the at least one printhead module;

determine an order in which at least some of the dot data is supplied to at least one of the at least one printhead modules, the order being deternuned at least partly on the basis of the correction factor, thereby to at least partially compensate for the rotational displacement; and supply the dot data to the printhead module.

Optionally the printer controller controls a printhead comprising at least one monolithic printhead module, the at least one printhead module having a plurality of rows of nozzles configured to extend, in use, across at least part of a printable pagewidth of the printhead, the nozzles in each row being grouped into at least first and second fire groups, the printhead module being configured to sequentially fire, for each row, the nozzles of each fire group, such that each nozzle in the sequence from each fire group is fired simultaneously with respective corresponding nozzles in the sequence in the other fire groups, wherein the nozzles are fired row by row such that the nozzles of each row are all fired before the nozzles of each subsequent row, wherein the printer controller is configured to provide one or more control signals that control the order of firing of the nozzles.

Optionally the printer controller outputs to a printhead module:
dot data to be printed with at least two different inks; and control data for controlling printing of the dot data;

the printer controller including at least one communication output, each or the communication output being configured to output at least some of the control data and at least some of the dot data for the at least two inks.

Optionally the printer controller supplies data to a printhead module including at least one row of printhead nozzles, at least one row including at least one displaced row portion, the displacement of the row portion including a component in a direction normal to that of a pagewidth to be printed.

Optionally the printer controller supplies print data to at least one printhead module capable of printing a maximum of n of channels of print data, the at least one printhead module being configurable into:

a first mode, in which the printhead module is configured to receive data for a first number of the channels; and a second mode, in which the printhead module is configured to receive print data for a second number of the channels, wherein the first number is greater than the second number;

wherein the printer controller is selectively configurable to supply dot data for the first and second modes.
Optionally the printer controller supplies data to a printhead comprising a plurality of printhead modules, the printhead being wider than a reticle step used in forming the modules, the printhead comprising at least two types of the modules, wherein each type is determined by its geometric shape in plan.

Optionally the printer controller supplies one or more control signals to a printhead module, the printhead module including at least one row that comprises a plurality of sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, such that:

(a) a fire signal is provided to nozzles at a first and nth position in each set of nozzles;
(b) a fire signal is provided to the next inward pair of nozzles in each set;

(c) in the event n is an even number, step (b) is repeated until all of the nozzles in each set has been fired;
and (d) in the event n is an odd number, step (b) is repeated until all of the nozzles but a central nozzle in each set have been fired, and then the central nozzle is fired.

Optionally the printer controller supplies one or more control signals to a printhead module, the printhead module including at least one row that comprises a plurality of adjacent sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, the method comprising providing, for each set of nozzles, a fire signal in accordance with the sequence: [nozzle position 1, nozzle position n, nozzle position 2, nozzle position (n-1), ... , nozzle position x], wherein nozzle position x is at or adjacent the centre of the set of nozzles.

Optionally the printer controller supplies dot data to a printhead module comprising at least first and second rows configured to print ink of a similar type or color, at least some nozzles in the first row being aligned with respective corresponding nozzles in the second row in a direction of intended media travel relative to the printhead, the printhead module being configurable such that the nozzles in the first and second pairs of rows are fired such that some dots output to print media are printed to by nozzles from the first pair of rows and at least some other dots output to print media are printed to by nozzles from the second pair of rows, the printer controller being configurable to supply dot data to the printhead module for printing.

Optionally the printer controller supplies dot data to at least one printhead module, the at least one printhead module comprising a plurality of rows, each of the rows comprising a plurality of nozzles for ejecting ink, wherein the printhead module includes at least first and second rows configured to print ink of a similar type or color, the printer controller being configured to supply the dot data to the at least one printhead module such that, in the event a nozzle in the first row is faulty, a corresponding nozzle in the second row prints an ink dot at a position on print media at or adjacent a position where the faulty nozzle would otherwise have printed it.

Optionally the printer controller receives first data and manipulating the first data to produce dot data to be printed, the print controller including at least two serial outputs for supplying the dot data to at least one printhead.
Optionally the printer controller supplies data to a printhead module including:

at least one row of print nozzles;

at least first and second shift registers for shifting in dot data supplied from a data source, wherein each shift register feeds dot data to a group of nozzles, and wherein each of the groups of the nozzles is interleaved with at least one of the other groups of the nozzles.

Optionally the printer controller supplies data to a printhead capable of printing a maximum of n of channels of print data, the printhead being configurable into:

a first mode, in which the printhead is configured to receive print data for a first number of the channels;
and a second mode, in which the printhead is configured to receive print data for a second number of the channels, wherein the first number is greater than the second number.

Optionally the printer controller supplies data to a printhead comprising a plurality of printhead modules, the printhead being wider than a reticle step used in forming the modules, the printhead comprising at least two types of the modules, wherein each type is determined by its geometric shape in plan.

Optionally the printer controller supplies data to a printhead module including at least one row that comprises a plurality of sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, such that, for each set of nozzles, a fire signal is provided in accordance with the sequence: [nozzle position 1, nozzle position n, nozzle position 2, nozzle position (n-1), ... , nozzle position x], wherein nozzle position x is at or adjacent the centre of the set of nozzles.

Optionally the printer controller supplies data to a printhead module including at least one row that comprises a plurality of adjacent sets of n adjacent nozzles, each of the nozzles being configured to expel the ink in response to a fire signal, the printhead being configured to output ink from nozzles at a first and nth position in each set of nozzles, and then each next inward pair of nozzles in each set, until:

in the event n is an even number, all of the nozzles in each set has been fired; and in the event n is an odd number, all of the nozzles but a central nozzle in each set have been fired, and then to fire the central nozzle.

Optionally the printer controller supplies data to a printhead module for receiving dot data to be printed using at 5 least two different inks and control data for controlling printing of the dot data, the printhead module including a communication input for receiving the dot data for the at least two colors and the control data.

Optionally the printer controller supplies data to a printhead module including at least one row of printhead nozzles, at least one row including at least one displaced row portion, the displacement of the row portion 10 including a component in a direction normal to that of a pagewidth to be printed.

Optionally the printer controller supplies data to a printhead module having a plurality of rows of nozzles configured to extend, in use, across at least part of a printable pagewidth, the nozzles in each row being grouped into at least first and second fire groups, the printhead module being configured to sequentially fire, for each row, 15 the nozzles of each fire group, such that each nozzle in the sequence from each fire group is fired simultaneously with respective corresponding nozzles in the sequence in the other fire groups, wherein the nozzles are fired row by row such that the nozzles of each row are all fired before the nozzles of each subsequent row.

Optionally the printer controller supplies data to a printhead module comprising at least first and second rows 20 configured to print ink of a similar type or color, at least some nozzles in the first row being aligned with respective corresponding nozzles in the second row in a direction of intended media travel relative to the printhead, the printhead module being configurable such that the nozzles in the first and second pairs of rows are fired such that some dots output to print media are printed to by nozzles from the first pair of rows and at least some other dots output to print media are printed to by nozzles from the second pair of rows.

Optionally the printer controller supplies data to a printhead module that includes:
at least one row of print nozzles;

at least first and second shift registers for shifting in dot data supplied from a data source, wherein each shift register feeds dot data to a group of nozzles, and wherein each of the groups of the nozzles is interleaved with at least one of the other groups of the nozzles.

Optionally the printer controller supplies data to a printhead module having a plurality of nozzles for expelling ink, the printhead module including a plurality of thermal sensors, each of the thermal sensors being configured to respond to a temperature at or adjacent at least one of the nozzles, the printhead module being configured to modify operation of the nozzles in response to the temperature rising above a first threshold.

Optionally the printer controller supplies data to a printhead module comprising a plurality of rows, each of the rows comprising a plurality of nozzles for ejecting ink, wherein the printhead module includes at least first and second rows configured to print ink of a similar type or color, and being configured such that, in the event a nozzle in the first row is faulty, a corresponding nozzle in the second row prints an ink dot at a position on print media at or adjacent a position where the faulty nozzle would otherwise have printed it.

Optionally the printer controller further includes a logic circuit accepting as inputs a masking signal and the thermal signal corresponding to the nozzle for which the dot data is intended, the logic circuit outputting the thermal signal to the input of the AND circuit in reliance on a value of the masking signal.

Optionally the value of the masking signal enables masking of the thermal signal for at least one nozzle position, including the nozzle for which the current dot data is intended.

Optionally the value of the masking signal enables masking of the thermal signal for a plurality of nozzle positions corresponding to a region of the printhead associated the nozzle for which the current dot data is intended.

Optionally the value of the masking signal enables masking of the thermal signal for all of the nozzle positions of the printhead.

In a twelfth aspect the present invention provides a printer controller for controlling a printhead comprising at least one monolithic printhead module, the at least one printhead module having a plurality of rows of nozzles configured to extend, in use, across at least part of a printable pagewidth of the printhead, the nozzles in each row being grouped into at least first and second fire groups, the printhead module being configured to sequentially fire, for each row, the nozzles of each fire group, such that each nozzle in the sequence from each fire group is fired simultaneously with respective corresponding nozzles in the sequence in the other fire groups, wherein the nozzles are fired row by row such that the nozzles of each row are all fired before the nozzles of each subsequent row, wherein the printer controller is configured to provide one or more control signals that control the order of firing of the nozzles.

Optionally the one or more control signals include a fire control sequence indicative of a first fire group to be fired.

Optionally, the printhead being configured to shift the fire control sequence through a shift register to cause subsequent firing of the second and any other fire groups, wherein the printer controller is configured to provide the fire control sequence during an initiation phase of the printhead, such that the fire control sequence does not need to be repeatedly provided by the printer controller while printing is taking place.

Optionally, the printhead being configured to shift the fire control sequence through a shift register to cause subsequent firing of the second and any other fire groups, wherein the printer controller is configured to provide the fire control sequence periodically during printing.

Optionally the printhead being configured to provide the fire control sequence on a per row or per print-line basis.

Optionally the printhead being configured to provide a fire enable signal in addition to the one or more fire control signals, such that the combination of the fire enable and fire control signals cause selected ones of the nozzles to fire in the predetermined sequence and in accordance with a predetermined timing.

In a further aspect the present invention provides a print engine including a printhead and a printer controller, the printhead comprising at least one monolithic printhead module, the at least one printhead module having a plurality of rows of nozzles configured to extend, in use, across at least part of a printable pagewidth of the printhead, the nozzles in each row being grouped into at least first and second fire groups, the printhead module being configured to sequentially fire, for each row, the nozzles of each fire group, such that each nozzle in the sequence from each fire group is fired simultaneously with respective corresponding nozzles in the sequence in the other fire groups, wherein the nozzles are fired row by row such that the nozzles of each row are all fired before the nozzles of each subsequent row, wherein the printer controller is configured to provide one or more control signals that control the order of firing of the nozzles.

Optionally the one or more control signals include a fire control sequence indicative of a first fire group to be fired.

Optionally the printhead being configured to shift the fire control sequence through a shift register to cause subsequent firing of the second and any other fire groups, wherein the printer controller is configured to provide the fire control sequence during an initiation phase of the printhead, such that the fire control sequence does not need to be repeatedly provided by the printer controller while printing is taking place.

Optionally, the printhead being configured to shift the fire control sequence through a shift register to cause subsequent firing of the second and any other fire groups, wherein the printer controller is configured to provide the fire control sequence periodically during printing.

Optionally the print engine being configured to provide the fire control sequence on a per row or per print-line basis.

Optionally the print engine being configured to provide a fire enable signal in addition to the one or more fire control signals, such that the combination of the fire enable and fire control signals cause selected ones of the nozzles to fire in the predetermined sequence and in accordance with a predetermined timing.

Optionally the printer controller is for implementing a method of at least partially compensating for errors in ink dot placement by at least one of a plurality of nozzles due to erroneous rotational displacement of a printhead module relative to a carrier, the nozzles being disposed on the printhead module, the method comprising the steps of:

(a) determining the rotational displacement;

(b) determining at least one correction factor that at least partially compensates for the ink dot displacement;
and (c) using the correction factor to alter the output of the ink dots to at least partially compensate for the rotational displacement.

Optionally the printer controller is for implementing a method of expelling ink from a printhead module including at least one row that comprises a plurality of adjacent sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, the method comprising providing, for each set of nozzles, a fire signal in accordance with the sequence: [nozzle position 1, nozzle position n, nozzle position 2, nozzle position (n-1), ... , nozzle position x], wherein nozzle position x is at or adjacent the centre of the set of nozzles.

Optionally the printer controller is for implementing a method of expelling ink from a printhead module including at least one row that comprises a plurality of sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, the method comprising the steps of:

(a) providing a fire signal to nozzles at a first and nth position in each set of nozzles;
(b) providing a fire signal to the next inward pair of nozzles in each set;

(c) in the event n is an even number, repeating step (b) until all of the nozzles in each set has been fired; and (d) in the event n is an odd number, repeating step (b) until all of the nozzles but a central nozzle in each set have been fired, and then firing the central nozzle.

Optionally the printer controller is manufactured in accordance with a method of manufacturing a plurality of printhead modules, at least some of which are capable of being combined in pairs to form bilithic pagewidth printheads, the method comprising the step of laying out each of the plurality of printhead modules on a wafer substrate, wherein at least one of the printhead modules is right-handed and at least another is left-handed.

Optionally the printer controller supplies data to a printhead module including:
at least one row of print nozzles;

at least two shift registers for shifting in dot data supplied from a data source to each of the at least one rows, wherein each print nozzle obtains dot data to be fired from an element of one of the shift registers.

Optionally the printer controller is installed in a printer comprising:

a printhead comprising at least a first elongate printhead module, the at least one printhead module including at least one row of print nozzles for expelling ink; and at least first and second printer controllers configured to receive print data and process the print data to output dot data to the printhead, wherein the first and second printer controllers are connected to a common input of the printhead.

Optionally the printer controller is installed in a printer comprising:

a printhead comprising first and second elongate printhead modules, the printhead modules being parallel to each other and being disposed end to end on either side of a join region;

at least first and second printer controllers configured to receive print data and process the print data to output dot data to the printhead, wherein the first printer controller outputs dot data only to the first printhead module and the second printer controller outputs dot data only to the second printhead module, wherein the printhead modules are configured such that no dot data passes between them.

Optionally the printer controller is installed in a printer comprising:

a printhead comprising first and second elongate printhead modules, the printhead modules being parallel to each other and being disposed end to end on either side of a join region, wherein the first printhead module is longer than the second printhead module;

at least first and second printer controllers configured to receive print data and process the print data to output dot data to the printhead, wherein: the first printer controller outputs dot data to both the first printhead module and the second printhead module; and the second printer controller outputs dot data only to the second printhead module.

Optionally the printer controller is installed in a printer comprising:

a printhead comprising first and second elongate printhead modules, the printhead modules being parallel to each other and being disposed end to end on either side of a join region, wherein the first printhead module is longer than the second printhead module;

at least first and second printer controllers configured to receive print data and process the print data to output dot data for the printhead, wherein: the first printer controller outputs dot data to both the first printhead module and the second controller; and the second printer controller outputs dot data to the second printhead module, wherein the dot data output by the second printer controller includes dot data it generates and at least some of the dot data received from the first printer controller.

Optionally the printer controller supplies dot data to at least one printhead module and at least partially compensating for errors in ink dot placement by at least one of a plurality of nozzles on the printhead module due to erroneous rotational displacement of the printhead module relative to a carrier, the printer being configured to:
access a correction factor associated with the at least one printhead module;

determine an order in which at least some of the dot data is supplied to at least one of the at least one printhead modules, the order being determined at least partly on the basis of the correction factor, thereby to at least partially compensate for the rotational displacement; and supply the dot data to the printhead module.

Optionally the printer controller supplies dot data to a printhead module having a plurality of nozzles for expelling ink, the printhead module including a plurality of thermal sensors, each of the thermal sensors being configured to respond to a temperature at or adjacent at least one of the nozzles, the printer controller being configured to modify operation of at least some of the nozzles in response to the temperature rising above a first threshold.

Optionally the printer controller outputs to a printhead module:
dot data to be printed with at least two different inks; and control data for controlling printing of the dot data;

the printer controller including at least one communication output, each or the communication output being configured to output at least some of the control data and at least some of the dot data for the at least two inks.
Optionally the printer controller supplies data to a printhead module including at least one row of printhead nozzles, at least one row including at least one displaced row portion, the displacement of the row portion including a component in a direction normal to that of a pagewidth to be printed.

Optionally the printer controller supplies print data to at least one printhead module capable of printing a maximum of n of channels of print data, the at least one printhead module being configurable into:

a first mode, in which the printhead module is configured to receive data for a first number of the channels; and a second mode, in which the printhead module is configured to receive print data for a second number of the channels, wherein the first number is greater than the second number;

wherein the printer controller is selectively configurable to supply dot data for the first and second modes.
Optionally the printer controller supplies data to a printhead comprising a plurality of printhead modules, the printhead being wider than a reticle step used in forming the modules, the printhead comprising at least two types of the modules, wherein each type is determined by its geometric shape in plan.

Optionally the printer controller supplies one or more control signals to a printhead module, the printhead module including at least one row that comprises a plurality of sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, such that:

(a) a fire signal is provided to nozzles at a first and nth position in each set of nozzles;

(b) a fire signal is provided to the next inward pair of nozzles in each set;

(c) in the event n is an even number, step (b) is repeated until all of the nozzles in each set has been fired;
and (d) in the event n is an odd number, step (b) is repeated until all of the nozzles but a central nozzle in each set have been fired, and then the central nozzle is fired.

Optionally the printer controller supplies one or more control signals to a printhead module, the printhead module including at least one row that comprises a plurality of adjacent sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, the method comprising providing, for each set of nozzles, a fire signal in accordance with the sequence: [nozzle position 1, nozzle position n, nozzle position 2, nozzle position (n-1), ... , nozzle position x], wherein nozzle position x is at or adjacent the centre of the set of nozzles.

Optionally the printer controller supplies dot data to a printhead module comprising at least first and second rows configured to print ink of a similar type or color, at least some nozzles in the first row being aligned with respective corresponding nozzles in the second row in a direction of intended media travel relative to the printhead, the printhead module being configurable such that the nozzles in the first and second pairs of rows are fired such that some dots output to print media are printed to by nozzles from the first pair of rows and at least some other dots output to print media are printed to by nozzles from the second pair of rows, the printer controller being configurable to supply dot data to the printhead module for printing.

Optionally the printer controller supplies dot data to at least one printhead module, the at least one printhead module comprising a plurality of rows, each of the rows comprising a plurality of nozzles for ejecting ink, wherein the printhead module includes at least first and second rows configured to print ink of a similar type or color, the printer controller being configured to supply the dot data to the at least one printhead module such that, in the event a nozzle in the first row is faulty, a corresponding nozzle in the second row prints an ink dot at a position on print media at or adjacent a position where the faulty nozzle would otherwise have printed it.
Optionally the printer controller receives first data and manipulating the first data to produce dot data to be printed, the print controller including at least two serial outputs for supplying the dot data to at least one printhead.
Optionally the printer controller supplies data to a printhead module including:

at least one row of print nozzles;

at least first and second shift registers for shifting in dot data supplied from a data source, wherein each shift register feeds dot data to a group of nozzles, and wherein each of the groups of the nozzles is interleaved with at least one of the other groups of the nozzles.

Optionally the printer controller supplies data to a printhead capable of printing a maximum of n of channels of print data, the printhead being configurable into:

a fust mode, in which the printhead is configured to receive print data for a first number of the channels;
and a second mode, in which the printhead is configured to receive print data for a second number of the channels, wherein the first number is greater than the second number.

Optionally the printer controller supplies data to a printhead comprising a plurality of printhead modules, the printhead being wider than a reticle step used in forming the modules, the printhead comprising at least two types of the modules, wherein each type is determined by its geometric shape in plan.

Optionally the printer controller supplies data to a printhead module including at least one row that comprises a plurality of sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, such that, for each set of nozzles, a fire signal is provided in accordance with the sequence: [nozzle position 1, nozzle position n, nozzle position 2, nozzle position (n-1), ... , nozzle position x], wherein nozzle position x is at or adjacent the centre of the set of nozzles.

Optionally the printer controller supplies data to a printhead module including at least one row that comprises a plurality of adjacent sets of n adjacent nozzles, each of the nozzles being configured to expel the ink in response to a fire signal, the printhead being configured to output ink from nozzles at a first and nth position in each set of nozzles, and then each next inward pair of nozzles in each set, until:

in the event n is an even number, all of the nozzles in each set has been fired; and in the event n is an odd number, all of the nozzles but a central nozzle in each set have been fired, and then to fire the central nozzle.

Optionally the printer controller supplies data to a printhead module for receiving dot data to be printed using at least two different inks and control data for controlling printing of the dot data, the printhead module including a communication input for receiving the dot data for the at least two colors and the control data.

Optionally the printer controller supplies data to a printhead module including at least one row of printhead nozzles, at least one row including at least one displaced row portion, the displacement of the row portion including a component in a direction normal to that of a pagewidth to be printed.

Optionally the printer controller supplies data to a printhead module having a plurality of rows of nozzles configured to extend, in use, across at least part of a printable pagewidth, the nozzles in each row being grouped into at least first and second fire groups, the printhead module being configured to sequentially fire, for each row, the nozzles of each fire group, such that each nozzle in the sequence from each fire group is fired simultaneously with respective corresponding nozzles in the sequence in the other fire groups, wherein the nozzles are fired row by row such that the nozzles of each row are all fired before the nozzles of each subsequent row.

Optionally the printer controller supplies data to a printhead module comprising at least first and second rows configured to print ink of a similar type or color, at least some nozzles in the first row being aligned with respective corresponding nozzles in the second row in a direction of intended media travel relative to the printhead, the printhead module being configurable such that the nozzles in the first and second pairs of rows are fired such that some dots output to print media are printed to by nozzles from the fust pair of rows and at least some other dots output to print media are printed to by nozzles from the second pair of rows.

Optionally the printer controller supplies data to a printhead module that includes:
at least one row of print nozzles;

at least first and second shift registers for shifting in dot data supplied from a data source, wherein each shift register feeds dot data to a group of nozzles, and wherein each of the groups of the nozzles is interleaved with at least one of the other groups of the nozzles.

Optionally the printer controller supplies data to a printhead module having a plurality of nozzles for expelling ink, the printhead module including a plurality of thennal sensors, each of the thermal sensors being configured to respond to a temperature at or adjacent at least one of the nozzles, the printhead module being configured to modify operation of the nozzles in response to the temperature rising above a first threshold.

Optionally the printer controller supplies data to a printhead module comprising a plurality of rows, each of the rows comprising a plurality of nozzles for ejecting ink, wherein the printhead module includes at least first and second rows configured to print ink of a similar type or color, and being configured such that, in the event a nozzle in the first row is faulty, a corresponding nozzle in the second row prints an ink dot at a position on print media at or adjacent a position where the faulty nozzle would otherwise have printed it.

Optionally the printhead module includes a plurality of pairs of the rows, each pair of rows including an odd row and an even row, the odd and even rows in each pair being offset from each other in both x and y directions relative to an intended direction of print media movement relative to the printhead, the printer controller being configured to control the at least one printhead module to cause firing of at least a plurality of the odd rows prior to firing any of the even rows, or vice versa.

Optionally all the odd rows are fired before any of the even rows are fired, or vice versa.

Optionally the printer controller configurable to control the printhead module such that the odd rows, or the even rows, or both, are fired in a predetermined order.

Optionally the printer controller configurable such that the predetermined order is selectable from a plurality of predetermined available orders.

Optionally the predetermined order is sequential.

Optionally the printer controller configurable such that the predetermined order can commence at any of a plurality of the rows.

In a thirteenth aspect the present invention provides a printer controller for outputting to a printhead module:
dot data to be printed with at least two different inks; and control data for controlling printing of the dot data;

the printer controller including at least one communication output, each or the communication output being configured to output at least some of the control data and at least some of the dot data for the at least two inks.

Optionally the communication output is configured to output the dot data and control data serially.

Optionally the printer controller further includes a plurality of the communication outputs.

Optionally the printer controller further includes a plurality of the communication outputs.

Optionally a print engine comprising a print controller and a plurality of printhead modules, the printhead modules being disposed end to end for printing a width exceeding that of any of the individual printhead modules, the communications input of each of the printhead modules being connected to a common dot data and control data bus, the common dot data and control data bus being in functional communication with the communication output.

Optionally each module is configured to respond to dot data and control data on the bus only when it is intended for that module.

Optionally a printer incorporating a print engine comprising a print controller and a plurality of printhead modules, the printhead modules being disposed end to end for printing a width exceeding that of any of the individual printhead modules, the communications input of each of the printhead modules being connected to a common dot data and control data bus, the common dot data and control data bus being in functional communication with the communication output.

Optionally a printer incorporating a print controller for outputting to a printhead module:
dot data to be printed with at least two different inks; and control data for controlling printing of the dot data;

the printer controller including at least one communication output, each or the communication output being configured to output at least some of the control data and at least some of the dot data for the at least two inks.
Optionally the printhead modules together fonn a pagewidth printhead.

Optionally the printer further including a pagewidth printhead comprising a plurality of the printhead modules.
Optionally the printer controller is for implementing a method of at least partially compensating for errors in ink dot placement by at least.one of a plurality of nozzles due to erroneous rotational displacement of a printhead module relative to a carrier, the nozzles being disposed on the printhead module, the method comprising the steps of:

(a) determining the rotational displacement;

(b) determining at least one correction factor that at least partially compensates for the ink dot displacement;
and (c) using the correction factor to alter the output of the ink dots to at least partially compensate for the rotational displacement.

Optionally the printer controller is for implementing a method of expelling ink from a printhead module including at least one row that comprises a plurality of adjacent sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, the method comprising providing, for each set of nozzles, a fire signal in accordance with the sequence: [nozzle position 1, nozzle position n, nozzle position 2, nozzle position (n-1), ... , nozzle position x], wherein nozzle position x is at or adjacent the centre of the set of nozzles.
Optionally the printer controller is for implementing a method of expelling ink from a printhead module including at least one row that comprises a plurality of sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, the method comprising the steps of:

(a) providing a fire signal to nozzles at a first and nth position in each set of nozzles;
(b) providing a fire signal to the next inward pair of nozzles in each set;

(c) in the event n is an even number, repeating step (b) until all of the nozzles in each set has been fired; and (d) in the event n is an odd number, repeating step (b) until all of the nozzles but a central nozzle in each set have been fired, and then firing the central nozzle.

Optionally the printer controller is manufactured in accordance with a method of manufacturing a plurality of printhead modules, at least some of which are capable of being combined in pairs to form bilithic pagewidth printheads, the method comprising the step of laying out each of the plurality of printhead modules on a wafer substrate, wherein at least one of the printhead modules is right-handed and at least another is left-handed.

Optionally the printer controller supplies data to a printhead module including:

at least one row of print nozzles;

at least two shift registers for shifting in dot data supplied from a data source to each of the at least one rows, wherein each print nozzle obtains dot data to be fired from an element of one of the shift registers.
Optionally the printer controller is installed in a printer comprising:

a printhead comprising at least a first elongate printhead module, the at least one printhead module including at least one row of print nozzles for expelling ink; and at least first and second printer controllers configured to receive print data and process the print data to output dot data to the printhead, wherein the first and second printer controllers are connected to a conunon input of the printhead.

Optionally the printer controller is installed in a printer comprising:

a printhead comprising first and second elongate printhead modules, the printhead modules being parallel to each other and being disposed end to end on either side of a join region;

at least first and second printer controllers configured to receive print data and process the print data to output dot data to the printhead, wherein the fust printer controller outputs dot data only to the first printhead module and the second printer controller outputs dot data only to the second printhead module, wherein the printhead modules are configured such that no dot data passes between them.
Optionally the printer controller is installed in a printer comprising:

a printhead comprising first and second elongate printhead modules, the printhead modules being parallel to each other and being disposed end to end on either side of a join region, wherein the first printhead module is longer than the second printhead module;

at least first and second printer controllers configured to receive print data and process the print data to output dot data to the printhead, wherein: the first printer controller outputs dot data to both the first printhead module and the second printhead module; and the second printer controller outputs dot data only to the second printhead module.

Optionally the printer controller is installed in a printer comprising:

a printhead comprising first and second elongate printhead modules, the printhead modules being parallel to each other and being disposed end to end on either side of a join region, wherein the first printhead module is longer than the second printhead module;

at least first and second printer controllers configured to receive print data and process the print data to output dot data for the printhead, wherein: the first printer controller outputs dot data to both the first printhead module and the second controller; and the second printer controller outputs dot data to the second printhead module, wherein the dot data output by the second printer controller includes dot data it generates and at least some of the dot data received from the fust printer controller.

Optionally the printer controller supplies dot data to at least one printhead module and at least partially compensating for errors in ink dot placement by at least one of a plurality of nozzles on the printhead module due to erroneous rotational displacement of the printhead module relative to a carrier, the printer being configured to:
access a correction factor associated with the at least one printhead module;

determine an order in which at least some of the dot data is supplied to at least one of the at least one printhead modules, the order being detetmined at least partly on the basis of the correction factor, thereby to at least partially compensate for the rotational displacement; and supply the dot data to the printhead module.

Optionally the printer controller supplies dot data to a printhead module having a plurality of nozzles for expelling ink, the printhead module including a plurality of thermal sensors, each of the thermal sensors being configured to respond to a temperature at or adjacent at least one of the nozzles, the printer controller being configured to modify operation of at least some of the nozzles in response to the temperature rising above a first threshold.
Optionally the printer controller controls a printhead comprising at least one monolithic printhead module, the at least one printhead module having a plurality of rows of nozzles configured to extend, in use, across at least part of a printable pagewidth of the printhead, the nozzles in each row being grouped into at least first and second fire groups, the printhead module being configured to sequentially fire, for each row, the nozzles of each fire group, such that each nozzle in the sequence from each fire group is fired simultaneously with respective corresponding nozzles in the sequence in the other fire groups, wherein the nozzles are fired row by row such that the nozzles of each row are all fired before the nozzles of each subsequent row, wherein the printer controller is configured to provide one or more control signals that control the order of firing of the nozzles.

Optionally the printer controller supplies data to a printhead module including at least one row of printhead nozzles, at least one row including at least one displaced row portion, the displacement of the row portion including a component in a direction normal to that of a pagewidth to be printed.

Optionally the printer controller supplies print data to at least one printhead module capable of printing a maximum of n of channels of print data, the at least one printhead module being configurable into:

a first mode, in which the printhead module is configured to receive data for a first number of the channels; and a second mode, in which the printhead module is configured to receive print data for a second number of the channels, wherein the first number is greater than the second number;

wherein the printer controller is selectively configurable to supply dot data for the first and second modes.
Optionally the printer controller supplies data to a printhead comprising a plurality of printhead modules, the printhead being wider than a reticle step used in forming the modules, the printhead comprising at least two types of the modules, wherein each type is determined by its geometric shape in plan.

Optionally the printer controller supplies one or more control signals to a printhead module, the printhead module including at least one row that comprises a plurality of sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, such that:

(a) a fire signal is provided to nozzles at a first and nth position in each set of nozzles;
(b) a fire signal is provided to the next inward pair of nozzles in each set;

(c) in the event n is an even number, step (b) is repeated until all of the nozzles in each set has been fired;
and (d) in the event n is an odd number, step (b) is repeated until all of the nozzles but a central nozzle in each set have been fired, and then the central nozzle is fired.

Optionally the printer controller supplies one or more control signals to a printhead module, the printhead module including at least one row that comprises a plurality of adjacent sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, the method comprising providing, for each set of nozzles, a fire signal in accordance with the sequence: [nozzle position 1, nozzle position n, nozzle position 2, nozzle position (n-1), ... , nozzle position x], wherein nozzle position x is at or adjacent the centre of the set of nozzles.

Optionally the printer controller supplies dot data to a printhead module comprising at least first and second rows configured to print ink of a similar type or color, at least some nozzles in the first row being aligned with respective corresponding nozzles in the second row in a direction of intended media travel relative to the printhead, the printhead module being configurable such that the nozzles in the first and second pairs of rows are fired such that some dots output to print media are printed to by nozzles from the first pair of rows and at least some other dots output to print media are printed to by nozzles from the second pair of rows, the printer controller being configurable to supply dot data to the printhead module for printing.

Optionally the printer controller supplies dot data to at least one printhead module, the at least one printhead module comprising a plurality of rows, each of the rows comprising a plurality of nozzles for ejecting ink, wherein the printhead module includes at least first and second rows configured to print ink of a similar type or color, the printer controller being configured to supply the dot data to the at least one printhead module such that, in the event a nozzle in the first row is faulty, a corresponding nozzle in the second row prints an ink dot at a position on print media at or adjacent a position where the faulty nozzle would otherwise have printed it.
Optionally the printer controller receives first data and manipulating the first data to produce dot data to be printed, the print controller including at least two serial outputs for supplying the dot data to at least one printhead.

Optionally the printer controller supplies data to a printhead module including:
at least one row of print nozzles;

at least first and second shift registers for shifting in dot data supplied from a data source, wherein each shift register feeds dot data to a group of nozzles, and wherein each of the groups of the nozzles is interleaved with at least one of the other groups of the nozzles.

Optionally the printer controller supplies data to a printhead capable of printing a maximum of n of channels of print data, the printhead being configurable into:

a first mode, in which the printhead is configured to receive print data for a first number of the channels;
and a second mode, in which the printhead is configured to receive print data for a second number of the channels, wherein the first number is greater than the second number.

Optionally the printer controller supplies data to a printhead comprising a plurality of printhead modules, the printhead being wider than a reticle step used in forming the modules, the printhead comprising at least two types of the modules, wherein each type is determined by its geometric shape in plan.

Optionally the printer controller supplies data to a printhead module including at least one row that comprises a plurality of sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, such that, for each set of nozzles, a fire signal is provided in accordance with the sequence: [nozzle position 1, nozzle position n, nozzle position 2, nozzle position (n-1), ... , nozzle position x], wherein nozzle position x is at or adjacent the centre of the set of nozzles.

Optionally the printer controller supplies data to a printhead module including at least one row that comprises a plurality of adjacent sets of n adjacent nozzles, each of the nozzles being configured to expel the ink in response to a fire signal, the printhead being configured to output ink from nozzles at a first and nth position in each set of nozzles, and then each next inward pair of nozzles in each set, until:

in the event n is an even number, all of the nozzles in each set has been fired; and in the event n is an odd number, all of the nozzles but a central nozzle in each set have been fired, and.then to fire the central nozzle.

Optionally the printer controller supplies data to a printhead module for receiving dot data to be printed using at least two different inks and control data for controlling printing of the dot data, the printhead module including a communication input for receiving the dot data for the at least two colors and the control data.

Optionally the printer controller supplies data to a printhead module including at least one row of printhead nozzles, at least one row including at least one displaced row portion, the displacement of the row portion including a component in a direction normal to that of a pagewidth to be printed.

Optionally the printer controller supplies data to a printhead module having a plurality of rows of nozzles configured to extend, in use, across at least part of a printable pagewidth, the nozzles in each row being grouped into at least first and second fire groups, the printhead module being configured to sequentially fire, for each row, the nozzles of each fire group, such that each nozzle in the sequence from each fire group is fired simultaneously with respective corresponding nozzles in the sequence in the other fire groups, wherein the nozzles are fired row by row such that the nozzles of each row are all fired before the nozzles of each subsequent row.

Optionally the printer controller supplies data to a printhead module comprising at least first and second rows configured to print ink of a similar type or color, at least some nozzles in the first row being aligned with respective corresponding nozzles in the second row in a direction of intended media travel relative to'the printhead, the printhead module being configurable such that the nozzles in the first and second pairs of rows are fired such that some dots output to print media are printed to by nozzles from the first pair of rows and at least some other dots output to print media are printed to by nozzles from the second pair of rows.

Optionally the printer controller provides data to a printhead module that includes:
at least one row of print nozzles;

at least first and second shift registers for shifting in dot data supplied from a data source, wherein each shift register feeds dot data to a group of nozzles, and wherein each of the groups of the nozzles is interleaved with at least one of the other groups of the nozzles.

Optionally the printer controller supplies data to a printhead module having a plurality of nozzles for expelling ink, the printhead module including a plurality of thermal sensors, each of the thennal sensors being configured to respond to a temperature at or adjacent at least one of the nozzles, the printhead module being configured to modify operation of the nozzles in response to the temperature rising above a first threshold.

Optionally the printer controller supplies data to a printhead module comprising a plurality of rows, each of the rows comprising a plurality of nozzles for ejecting ink, wherein the printhead module includes at least first and second rows configured to print ink of a similar type or color, and being configured such that, in the event a nozzle in the first row is faulty, a corresponding nozzle in the second row prints an ink dot at a position on print media at or adjacent a position where the faulty nozzle would otherwise have printed it.

In a fourteenth aspect the present invention provides a printer controller for supplying data to a printhead module including at least one row of printhead nozzles, at least one row including at least one displaced row portion, the displacement of the row portion including a component in a direction normal to that of a pagewidth to be printed, the printer controller being configured to control order and timing of the data supplied to the printhead such that the dropped row is compensated for during printing by the printhead module.

Optionally the displaced row portion is disposed adjacent one end of the printhead module.

Optionally the printhead module includes a plurality of the rows, wherein each of at least a plurality of the rows includes one of the displaced row portions.

Optionally the displaced row portions of at least some of the rows are different in length than the displaced row portions of at least some of the other rows.

Optionally each of the rows has a displaced row portion, and the sizes of the respective displaced row portions increase from row to row in the direction normal to that of the pagewidth to be printed.

Optionally the printer controller supplies the data to a printhead comprising a plurality of the printhead modules.
Optionally the printer controller supplies data to a printhead comprising a plurality of the printhead modules, wherein the displaced row portion of at least one of the printhead modules is disposed adjacent another of the printhead modules.

Optionally the printhead modules are the same shape and configuration as each other, and are arranged end to end across the intended print width.

Optionally, the printhead being a pagewidth printhead.
Optionally, the printhead being a pagewidth printhead.

Optionally the printer controller is for implementing a method of at least partially compensating for errors in ink dot placement by at least one of a plurality of nozzles due to erroneous rotational displacement of a printhead module relative to a carrier, the nozzles being disposed on the printhead module, the method comprising the steps of:

(a) determining the rotational displacement;

(b) determining at least one correction factor that at least partially compensates for the ink dot displacement;
and (c) using the correction factor to alter the output of the ink dots to at least partially compensate for the rotational displacement.

Optionally the printer controller is for implementing a method of expelling ink from a printhead module including at least one row that comprises a plurality of adjacent sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, the method comprising providing, for each set of nozzles, a fire signal in accordance with the sequence: [nozzle position 1, nozzle position n, nozzle position 2, nozzle position (n-1), ... , nozzle position x], wherein nozzle position x is at or adjacent the centre of the set of nozzles.
Optionally the printer controller is for implementing a method of expelling ink from a printhead module including at least one row that comprises a plurality of sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, the method comprising the steps of:

(a) providing a fire signal to nozzles at a first and nth position in each set of nozzles;
(b) providing a fire signal to the next inward pair of nozzles in each set;

(c) in the event n is an even number, repeating step (b) until all of the nozzles in each set has been fired; and (d) in the event n is an odd number, repeating step (b) until all of the nozzles but a central nozzle in each set have been fired, and then firing the central nozzle.

Optionally the printer controller is manufactured in accordance with a method of manufacturing a plurality of printhead modules, at least some of which are capable of being combined in pairs to form bilithic pagewidth printheads, the method comprising the step of laying out each of the plurality of printhead modules on a wafer substrate, wherein at least one of the printhead modules is right-handed and at least another is left-handed.

Optionally the printer controller supplies data to a printhead module including:
at least one row of print nozzles;

at least two shift registers for shifting in dot data supplied from a data source to each of the at least one rows, wherein each print nozzle obtains dot data to be fired from an element of one of the shift registers.

Optionally the printer controller is installed in a printer comprising:

a printhead comprising at least a first elongate printhead module, the at least one printhead module including at least one row of print nozzles for expelling ink; and at least first and second printer controllers configured to receive print data and process the print data to output dot data to the printhead, wherein the first and second printer controllers are connected to a common input of the printhead.

Optionally the printer controller is installed in a printer comprising:

a printhead comprising first and second elongate printhead modules, the printhead modules being parallel to each other and being disposed end to end on either side of a join region;

at least first and second printer controllers configured to receive print data and process the print data to output dot data to the printhead, wherein the fust printer controller outputs dot data only to the first printhead module and the second printer controller outputs dot data only to the second printhead module, wherein the printhead modules are configured such that no dot data passes between them.

Optionally the printer controller is installed in a printer comprising:

a printhead comprising first and second elongate printhead modules, the printhead modules being parallel to each other and being disposed end to end on either side of a join region, wherein the first printhead module is longer than the second printhead module;

at least first and second printer controllers configured to receive print data and process the print data to output dot data to the printhead, wherein: the first printer controller outputs dot data to both the fust printhead module and the second printhead module; and the second printer controller outputs dot data only to the second printhead module.

Optionally the printer controller is installed in a printer comprising:

a printhead comprising first and second elongate printhead modules, the printhead modules being parallel to each other and being disposed end to end on either side of a join region, wherein the first printhead module is longer than the second printhead module;

at least first and second printer controllers configured to receive print data and process the print data to output dot data for the printhead, wherein: the first printer controller outputs dot data to both the first printhead module and the second controller; and the second printer controller outputs dot data to the second printhead module, wherein the dot data output by the second printer controller includes dot data it generates and at least some of the dot data received from the first printer controller.

Optionally the printer controller supplies dot data to at least one printhead module and at least partially compensating for errors in ink dot placement by at least one of a plurality of nozzles on the printhead module due to erroneous rotational displacement of the printhead module relative to a carrier, the printer being configured to:

access a correction factor associated with the at least one printhead module;

determine an order in which at least some of the dot data is supplied to at least one of the at least one printhead modules, the order being determined at least partly on the basis of the correction factor, thereby to at least partially compensate for the rotational displacement; and supply the dot data to the printhead module.

Optionally the printer controller supplies dot data to a printhead module having a plurality of nozzles for expelling ink, the printhead module including a plurality of thennal sensors, each of the thermal sensors being configured to respond to a temperature at or adjacent at least one of the nozzles, the printer controller being configured to modify operation of at least some of the nozzles in response to the temperature rising above a first threshold.

Optionally the printer controller controls a printhead comprising at least one monolithic printhead module, the at least one printhead module having a plurality of rows of nozzles configured to extend, in use, across at least part of a printable pagewidth of the printhead, the nozzles in each row being grouped into at least first and second fire groups, the printhead module being configured to sequentially fire, for each row, the nozzles of each fire group, such that each nozzle in the sequence from each fire group is fired simultaneously with respective corresponding nozzles in the sequence in the other fire groups, wherein the nozzles are fired row by row such that the nozzles of each row are all fired before the nozzles of each subsequent row, wherein the printer controller is configured to provide one or more control signals that control the order of firing of the nozzles.

Optionally the printer controller outputs to a printhead module:
dot data to be printed with at least two different inks; and control data for controlling printing of the dot data;

the printer controller including at least one communication output, each or the communication output being configured to output at least some of the control data and at least some of the dot data for the at least two inks.

Optionally the printer controller supplies print data to at least one printhead module capable of printing a maximum of n of channels of print data, the at least one printhead module being configurable into:

a first mode, in which the printhead module is configured to receive data for a first number of the channels; and a second mode, in which the printhead module is configured to receive print data for a second number of the channels, wherein the first number is greater than the second number;

wherein the printer controller is selectively configurable to supply dot data for the first and second modes.
Optionally the printer controller supplies data to a printhead comprising a plurality of printhead modules, the printhead being wider than a reticle step used in forming the modules, the printhead comprising at least two types of the modules, wherein each type is determined by its geometric shape in plan.

Optionally the printer controller supplies one or more control signals to a printhead module, the printhead module including at least one row that comprises a plurality of sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, such that:

(a) a fire signal is provided to nozzles at a first and nth position in each set of nozzles;
(b) a fire signal is provided to the next inward pair of nozzles in each set;

(c) in the event n is an even number, step (b) is repeated until all of the nozzles in each set has been fired;
and (d) in the event n is an odd number, step (b) is repeated until all of the nozzles but a central nozzle in each set have been fired, and then the central nozzle is fired.

Optionally the printer controller supplies one or more control signals to a printhead module, the printhead module including at least one row that comprises a plurality of adjacent sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, the method comprising providing, for each set of nozzles, a fire signal in accordance with the sequence: [nozzle position 1, nozzle position n, nozzle position 2, nozzle position (n-1), ... , nozzle position x], wherein nozzle position x is at or adjacent the centre of the set of nozzles.

Optionally the printer controller supplies dot data to a printhead module comprising at least first and second rows configured to print ink of a similar type or color, at least some nozzles in the first row being aligned with respective corresponding nozzles in the second row in a direction of intended media travel relative to the printhead, the printhead module being configurable such that the nozzles in the first and second pairs of rows are fired such that some dots output to print media are printed to by nozzles from the first pair of rows and at least some other dots output to print media are printed to by nozzles from the second pair of rows, the printer controller being configurable to supply dot data to the printhead module for printing.

Optionally the printer controller supplies dot data to at least one printhead module, the at least one printhead module comprising a plurality of rows, each of the rows comprising a plurality of nozzles for ejecting ink, wherein the printhead module includes at least first and second rows configured to print ink of a similar type or color, the printer controller being configured to supply the dot data to the at least one printhead module such that, in the event a nozzle in the first row is faulty, a corresponding nozzle in the second row prints an ink dot at a position on print media at or adjacent a position where the faulty nozzle would otherwise have printed it.

Optionally the printer controller receives fust data and manipulating the first data to produce dot data to be printed, the print controller including at least two serial outputs for supplying the dot data to at least one printhead.
Optionally the printer controller supplies data to a printhead module including:

at least one row of print nozzles;

at least first and second shift registers for shifting in dot data supplied from a data source, wherein each shift register feeds dot data to a group of nozzles, and wherein each of the groups of the nozzles is interleaved with at least one of the other groups of the nozzles.

Optionally the printer controller supplies data to a printhead capable of printing a maximum of n of channels of print data, the printhead being configurable into:

a first mode, in which the printhead is configured to receive print data for a first number of the channels;
and a second mode, in which the printhead is configured to receive print data for a second number of the channels, wherein the first number is greater than the second number.

Optionally the printer controller supplies data to a printhead comprising a plurality of printhead modules, the printhead being wider than a reticle step used in forming the modules, the printhead comprising at least two types of the modules, wherein each type is determined by its geometric shape in plan.

Optionally the printer controller supplies data to a printhead module including at least one row that comprises a plurality of sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, such that, for each set of nozzles, a fire signal is provided in accordance with the sequence: [nozzle position 1, nozzle position n, nozzle position 2, nozzle position (n-1), ... , nozzle position x], wherein nozzle position x is at or adjacent the centre of the set of nozzles.

Optionally the printer controller supplies data to a printhead module including at least one row that comprises a plurality of adjacent sets of n adjacent nozzles, each of the nozzles being configured to expel the ink in response to a fire signal, the printhead being configured to output ink from nozzles at a first and nth position in each set of nozzles, and then each next inward pair of nozzles in each set, until:

in the event n is an even number, all of the nozzles in each set has been fired; and in the event n is an odd number, all of the nozzles but a central nozzle in each set have been fired, and then to fire the central nozzle.

Optionally the printer controller supplies data to a printhead module for receiving dot data to be printed using at least two different inks and control data for controlling printing of the dot data, the printhead module including a communication input for receiving the dot data for the at least two colors and the control data.

Optionally the printer controller supplies data to a printhead module including at least one row of printhead nozzles, at least one row including at least one displaced row portion, the displacement of the row portion including a component in a direction normal to that of a pagewidth to be printed.

Optionally the printer controller supplies data to a printhead module having a plurality of rows of nozzles configured to extend, in use, across at least part of a printable pagewidth, the nozzles in each row being grouped into at least first and second fire groups, the printhead module being configured to sequentially fire, for each row, the nozzles of each fire group, such that each nozzle in the sequence from each fire group is fired simultaneously with respective corresponding nozzles in the sequence in the other fire groups, wherein the nozzles are fired row by row such that the nozzles of each row are all fired before the nozzles of each subsequent row.

Optionally the printer controller supplies data to a printhead module comprising at least first and second rows configured to print ink of a similar type or color, at least some nozzles in the first row being aligned with respective corresponding nozzles in the second row in a direction of intended media travel relative to the printhead, the printhead module being configurable such that the nozzles in the first and second pairs of rows are fired such that some dots output to print media are printed to by nozzles from the first pair of rows and at least some other dots output to print media are printed to by nozzles from the second pair of rows.

Optionally the printer controller supplies data to a printhead module that includes:
at least one row of print nozzles;

at least first and second shift registers for shifting in dot data supplied from a data source, wherein each shift register feeds dot data to a group of nozzles, and wherein each of the groups of the nozzles is interleaved with at least one of the other groups of the nozzles.

Optionally the printer controller supplies data to a printhead module having a plurality of nozzles for expelling ink, the printhead module including a plurality of thermal sensors, each of the thermal sensors being configured to respond to a temperature at or adjacent at least one of the nozzles, the printhead module being configured to modify operation of the nozzles in response to the temperature rising above a first threshold.

Optionally the printer controller supplies data to a printhead module comprising a plurality of rows, each of the rows comprising a plurality of nozzles for ejecting ink, wherein the printhead module includes at least first and second rows configured to print ink of a similar type or color, and being configured such that, in the event a nozzle in the first row is faulty, a con:esponding nozzle in the second row prints an ink dot at a position on print media at or adjacent a position where the faulty nozzle would otherwise have printed it.

In a fifteenth aspect the present invention provides printer controller for supplying print data to at least one printhead module capable of printing a maximum of n of channels of print data, the at least one printhead module being configurable into:

a first mode, in which the printhead module is configured to receive data for a first number of the channels; and a second mode, in which the printhead module is configured to receive print data for a second number of the channels, wherein the first number is greater than the second number;

wherein the printer controller is selectively configurable to supply dot data for the first and second modes.

Optionally the first number is n.

Optionally the first number is less than n.

Optionally the printhead module is configurable into at least one other mode, in which the at least one printhead module is configured to receive print data for a third number of print channels other than the first and second numbers, the printer controller being selectively configurable to supply the print data for the third number of print channels.

Optionally n is 4 and the second number is less than 4.

Optionally n is 5 and the second number is less than 5.
Optionally n is 6 and the second number is less than 6.
Optionally the second number is 3, 4 or 5.

Optionally the print engine includes the print controller for supplying print data to at least one printhead module capable of printing a maximum of n of channels of print data, the at least one printhead module being configurable into:

a first mode, in which the printhead module is configured to receive data for a first number of the channels; and a second mode, in which the printhead module is configured to receive print data for a second number of the channels, wherein the first number is greater than the second number;

wherein the printer controller is selectively configurable to supply dot data for the first and second modes;
and the at least one printhead module.

Optionally the mode is selected based on the contents of a memory associated with the at least one printhead module.

Optionally the memory is a register.

Optionally the register is on an integrated circuit forming part of the print engine.

Optionally the printer includes a printer controller for supplying print data to at least one printhead module capable of printing a maximum of n of channels of print data, the at least one printhead module being configurable into:

a first mode, in which the printhead module is configured to receive data for a first number of the channels; and a second mode, in which the printhead module is configured to receive print data for a second number of the channels, wherein the first number is greater than the second number;

wherein the printer controller is selectively configurable to supply dot data for the first and second modes.
Optionally the printer includes a print engine including the print controller for supplying print data to at least one printhead module capable of printing a maximum of n of channels of print data, the at least one printhead module being configurable into:

a first mode, in which the printhead module is configured to receive data for a first number of the channels; and a second mode, in which the printhead module is configured to receive print data for a second number of the channels, wherein the first number is greater than the second number;

wherein the printer controller is selectively configurable to supply dot data for the first and second modes;
and the at least one printhead module.

Optionally the printer includes a printer controller for supplying print data to at least one printhead module capable of printing a maximum of n of channels of print data, the at least one printhead module being configurable into:

a fust mode, in which the printhead module is configured to receive data for a first number of the channels; and a second mode, in which the printhead module is configured to receive print data for a second number of the channels, wherein the first number is greater than the second number;

wherein the printer controller is selectively configurable to supply dot data for the first and second modes; and including a pagewidth printhead comprising a plurality of the printhead modules capable of printing a maximum of n of channels of print data, the at least one printhead module being configurable into:

a first mode, in which the printhead module is configured to receive data for a first number of the channels; and a second mode, in which the printhead module is configured to receive print data for a second number of the channels, wherein the first number is greater than the second number;

wherein the printer controller is selectively configurable to supply dot data for the first and second modes.
Optionally the printer controller for implementing a method of at least partially compensating for errors in ink dot placement by at least one of a plurality of nozzles due to erroneous rotational displacement of a printhead module relative to a carrier, the nozzles being disposed on the printhead module, the method comprising the steps of:
(a) determining the rotational displacement;

(b) determining at least one correction factor that at least partially compensates for the ink dot displacement;
and (c) using the correction factor to alter the output of the ink dots to at least partially compensate for the rotational displacement.

Optionally the printer controller for implementing a method of expelling ink from a printhead module including at least one row that comprises a plurality of adjacent sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, the method comprising providing, for each set of nozzles, a fire signal in accordance with the sequence: [nozzle position 1, nozzle position n, nozzle position 2, nozzle position (n-1), ... , nozzle position x], wherein nozzle position x is at or adjacent the centre of the set of nozzles.
Optionally the printer controller for implementing a method of expelling ink from a printhead module including at least one row that comprises a plurality of sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, the method comprising the steps of:

(a) providing a fire signal to nozzles at a first and nth position in each set of nozzles;
(b) providing a fire signal to the next inward pair of nozzles in each set;

(c) in the event n is an even number, repeating step (b) until all of the nozzles in each set has been fired; and (d) in the event n is an odd number, repeating step (b) until all of the nozzles but a central nozzle in each set have been fired, and then firing the central nozzle.

Optionally the printer controller manufactured in accordance with a method of manufacturing a plurality of printhead modules, at least some of which are capable of being combined in pairs to form bilithic pagewidth printheads, the method comprising the step of laying out each of the plurality of printhead modules on a wafer substrate, wherein at least one of the printhead modules is right-handed and at least another is left-handed.
Optionally the printer controller supplies data to a printhead module including:

at least one row of print nozzles;

at least two shift registers for shifting in dot data supplied from a data source to each of the at least one rows, wherein each print nozzle obtains dot data to be fired from an element of one of the shift registers.
Optionally the printer controller installed in a printer comprising:

a printhead comprising at least a first elongate printhead module, the at least one printhead module including at least one row of print nozzles for expelling ink; and at least first and second printer controllers configured to receive print data and process the print data to output dot data to the printhead, wherein the first and second printer controllers are connected to a common input of the printhead.

Optionally the printer controller installed in a printer comprising:

a printhead comprising first and second elongate printhead modules, the printhead modules being parallel to each other and being disposed end to end on either side of a join region;

at least first and second printer controllers configured to receive print data and process the print data to output dot data to the printhead, wherein the first printer controller outputs dot data only to the first printhead module and the second printer controller outputs dot data only to the second printhead module, wherein the printhead modules are configured such that no dot data passes between them.
Optionally a printer controller installed in a printer comprising:

a printhead comprising first and second elongate printhead modules, the printhead modules being parallel to each other and being disposed end to end on either side of a join region, wherein the first printhead module is longer than the second printhead module;

at least first and second printer controllers configured to receive print data and process the print data to output dot data to the printhead, wherein: the first printer controller outputs dot data to both the first printhead module and the second printhead module; and the second printer controller outputs dot data only to the second printhead module.

Optionally the printer controller installed in a printer comprising:

a printhead comprising first and second elongate printhead modules, the printhead modules being parallel to each other and being disposed end to end on either side of a join region, wherein the first printhead module is longer than the second printhead module;

at least first and second printer controllers configured to receive print data and process the print data to output dot data for the printhead, wherein: the first printer controller outputs dot data to both the first printhead module and the second controller; and the second printer controller outputs dot data to the second printhead module, wherein the dot data output by the second printer controller includes dot data it generates and at least some of the dot data received from the fust printer controller.

Optionally the printer controller supplies dot data to at least one printhead module and at least partially compensating for errors in ink dot placement by at least one of a plurality of nozzles on the printhead module due to erroneous rotational displacement of the printhead module relative to a carrier, the printer being configured to:
access a con ection factor associated with the at least one printhead module;

determine an order in which at least some of the dot data is supplied to at least one of the at least one printhead modules, the order being determined at least partly on the basis of the correction factor, thereby to at least partially compensate for the rotational displacement; and supply the dot data to the printhead module.

Optionally the printer controller supplies dot data to a printhead module having a plurality of nozzles for expelling ink, the printhead module including a plurality of thermal sensors, each of the thermal sensors being configured to respond to a temperature at or adjacent at least one of the nozzles, the printer controller being configured to modify operation of at least some of the nozzles in response to the temperature rising above a first threshold.

Optionally the printer controller controls a printhead comprising at least one monolithic printhead module, the at least one printhead module having a plurality of rows of nozzles configured to extend, in use, across at least part of a printable pagewidth of the printhead, the nozzles in each row being grouped into at least first and second fire groups, the printhead module being configured to sequentially fire, for each row, the nozzles of each fire group, such that each nozzle in the sequence from each fire group is fired simultaneously with respective corresponding nozzles in the sequence in the other fire groups, wherein the nozzles are fired row by row such that the nozzles of each row are all fired before the nozzles of each subsequent row, wherein the printer controller is configured to provide one or more control signals that control the order of firing of the nozzles.
Optionally the printer controller outputs to a printhead module:

dot data to be printed with at least two different inks; and control data for controlling printing of the dot data;

the printer controller including at least one communication output, each or the communication output being configured to output at least some of the control data and at least some of the dot data for the at least two inks.
Optionally the printer controller supplies data to a printhead module including at least one row of printhead nozzles, at least one row including at least one displaced row portion, the displacement of the row portion including a component in a direction normal to that of a pagewidth to be printed.

Optionally the printer controller supplies data to a printhead comprising a plurality of printhead modules, the printhead being wider than a reticle step used in forming the modules, the printhead comprising at least two types of the modules, wherein each type is determined by its geometric shape in plan.

Optionally the printer controllers supplies one or more control signals to a printhead module, the printhead module including at least one row that comprises a plurality of sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, such that:

(a) a fire signal is provided to nozzles at a first and nth position in each set of nozzles;
(b) a fire signal is provided to the next inward pair of nozzles in each set;

(c) in the event n is an even number, step (b) is repeated until all of the nozzles in each set has been fired;
and (d) in the event n is an odd number, step (b) is repeated until all of the nozzles but a central nozzle in each set have been fired, and then the central nozzle is fired.

Optionally the printer controller supplies one or more control signals to a printhead module, the printhead module including at least one row that comprises a plurality of adjacent sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, the method comprising providing, for each set of nozzles, a fire signal in accordance with the sequence: [nozzle position 1, nozzle position n, nozzle position 2, nozzle position (n-1), ... , nozzle position x], wherein nozzle position x is at or adjacent the centre of the set of nozzles.

Optionally the printer controller supplies dot data to a printhead module comprising at least first and second rows configured to print ink of a similar type or color, at least some nozzles in the first row being aligned with respective corresponding nozzles in the second row in a direction of intended media travel relative to the printhead, the printhead module being configurable such that the nozzles in the first and second pairs of rows are fired such that some dots output to print media are printed to by nozzles from the first pair of rows and at least some other dots output to print media are printed to by nozzles from the second pair of rows, the printer controller being configurable to supply dot data to the printhead module for printing.

Optionally the printer controller supplies dot data to at least one printhead module, the at least one printhead module comprising a plurality of rows, each of the rows comprising a plurality of nozzles for ejecting ink, wherein the printhead module includes at least first and second rows configured to print ink of a similar type or color, the printer controller being configured to supply the dot data to the at least one printhead module such that, in the event a nozzle in the first row is faulty, a corresponding nozzle in the second row prints an ink dot at a position on print media at or adjacent a position where the faulty nozzle would otherwise have printed it.
Optionally the printer controller receives first data and manipulating the first data to produce dot data to be printed, the print controller including at least two serial outputs for supplying the dot data to at least one printhead.

Optionally the printer controller supplies data to a printhead module including:
at least one row of print nozzles;

at least first and second shift registers for shifting in dot data supplied from a data source, wherein each shift register feeds dot data to a group of nozzles, and wherein each of the groups of the nozzles is interleaved with at least one of the other groups of the nozzles.

Optionally the printer controller supplies data to a printhead capable of printing a maximum of n of channels of print data, the printhead being configurable into:

a first mode, in which the printhead is configured to receive print data for a first number of the channels;
and a second mode, in which the printhead is configured to receive print data for a second number of the channels, wherein the first number is greater than the second number.

Optionally the printer controller supplies data to a printhead comprising a plurality of printhead modules, the printhead being wider than a reticle step used in forming the modules, the printhead comprising at least two types of the modules, wherein each type is determined by its geometric shape in plan.

Optionally the printer controller supplies data to a printhead module including at least one row that comprises a plurality of sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, such that, for each set of nozzles, a fire signal is provided in accordance with the sequence: [nozzle position 1, nozzle position n, nozzle position 2, nozzle position (n-1), ... , nozzle positionx], wherein nozzle position x is at or adjacent the centre of the set of nozzles.

Optionally the printer controller supplies data to a printhead module including at least one row that comprises a plurality of adjacent sets of n adjacent nozzles, each of the nozzles being configured to expel the ink in response to a fire signal, the printhead being configured to output ink from nozzles at a first and nth position in each set of nozzles, and then each next inward pair of nozzles in each set, until:

in the event n is an even number, all of the nozzles in each set has been fired; and in the event n is an odd number, all of the nozzles but a central nozzle in each set have been fired, and then to fire the central nozzle.

Optionally the printer controller supplies data to a printhead module for receiving dot data to be printed using at least two different inks and control data for controlling printing of the dot data, the printhead module including a communication input for receiving the dot data for the at least two colors and the control data.

Optionally the printer controller supplies data to a printhead module including at least one row of printhead nozzles, at least one row including at least one displaced row portion, the displacement of the row portion including a component in a direction normal to that of a pagewidth to be printed.

Optionally the printer controller supplies data to a printhead module having a plurality of rows of nozzles configured to extend, in use, across at least part of a printable pagewidth, the nozzles in each row being grouped into at least first and second fire groups, the printhead module being configured to sequentially fire, for each row, the nozzles of each fire group, such that each nozzle in the sequence from each fire group is fired simultaneously with respective corresponding nozzles in the sequence in the other fire groups, wherein the nozzles are fired row by row such that the nozzles of each row are all fired before the nozzles of each subsequent row.

Optionally the printer controller supplies data to a printhead module comprising at least first and second rows configured to print ink of a'similar type or color, at least some nozzles in the first row being aligned with respective corresponding nozzles in the second row in a direction of intended media travel relative to the printhead, the printhead module being configurable such that the nozzles in the first and second pairs of rows are fired such that some dots output to print media are printed to by nozzles from the first pair of rows and at least some other dots output to print media are printed to by nozzles from the second pair of rows.

Optionally the printer controller supplies data to a printhead module that includes:
at least one row of print nozzles;

at least first and second shift registers for shifting in dot data supplied from a data source, wherein each shift register feeds dot data to a group of nozzles, and wherein each of the groups of the nozzles is interleaved with at least one of the other groups of the nozzles.

Optionally the printer controller supplies data to a printhead module having a plurality of nozzles for expelling ink, the printhead module including a plurality of thermal sensors, each of the thermal sensors being configured to respond to a temperature at or adjacent at least one of the nozzles, the printhead module being configured to modify operation of the nozzles in response to the temperature rising above a first threshold.

Optionally the printer controller supplies data to a printhead module comprising a plurality of rows, each of the rows comprising a plurality of nozzles for ejecting ink, wherein the printhead module includes at least first and second rows configured to print ink of a similar type or color, and being configured such that, in the event a nozzle in the first row is faulty, a corresponding nozzle in the second row prints an ink dot at a position on print media at or adjacent a position where the faulty nozzle would otherwise have printed it.

In a sixteenth aspect the present invention provides a printer controller for supplying data to a printhead comprising a plurality of printhead modules, the printhead being wider than a reticle step used in forming the modules, the printhead comprising at least two types of the modules, wherein each type is determined by its geometric shape in plan.

Optionally the printhead comprises a plurality of at least one of the types of module.

Optionally the printhead comprises a plurality of each of at least two of the types of module.
Optionally the printhead comprises two types of the module.

Optionally the two types of module altemate across a print width of the printhead.

Optionally, each of the modules including at least one row of print nozzles, wherein each of the at least one row of print nozzles includes at least a portion that extends at an acute angle to an intended relative direction of movement between the printhead and print media.

Optionally the different types of modules are configured, and arranged relative to each other, such that there is substantially no growth in offset of each of the at least one row of print nozzles in a direction across an intended print width of the printhead.

Optionally each of the printhead modules is a monolithic integrated circuit.

Optionally, each of the modules including at least one row of print nozzles, wherein each of the at least one rows includes at least two sub-rows, each of the sub-rows being parallel to each other and displaced relative to each other in a direction of intended movement of print media relative to the printhead.

Optionally at least one row in each of the printhead modules prints an ink corresponding to at least one row on an adjacent printhead module, wherein the corresponding rows of at least two of the different printhead modules are offset from each other in a direction of intended movement of print media relative to the printhead, Optionally the printhead being a pagewidth printhead.

Optionally the printhead being a pagewidth printhead.

Optionally, the printhead being a pagewidth printhead.

Optionally the printer controller is for implementing a method of at least partially compensating for errors in ink dot placement by at least one of a plurality of nozzles due to erroneous rotational displacement of a printhead module relative to a carrier, the nozzles being disposed on the printhead module, the method comprising the steps of:

(a) determining the rotational displacement;

(b) determining at least one correction factor that at least partially compensates for the ink dot displacement;
and (c) using the correction factor to alter the output of the ink dots to at least partially compensate for the rotational displacement.

Optionally the printer controller is for implementing a method of expelling ink from a printhead module including at least one row that comprises a plurality of adjacent sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, the method comprising providing, for each set of nozzles, a fire signal in accordance with the sequence: [nozzle position 1, nozzle position n, nozzle position 2, nozzle position (n-1), ... , nozzle position x], wherein nozzle position x is at or adjacent the centre of the set of nozzles.
Optionally the printer controller is for implementing a method of expelling ink from a printhead module including at least one row that comprises a plurality of sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, the method comprising the steps of:

(a) providing a fire signal to nozzles at a first and nth position in each set of nozzles;
(b) providing a fire signal to the next inward pair of nozzles in each set;

(c) in the event n is an even number, repeating step (b) until all of the nozzles in each set has been fired; and (d) in the event n is an odd number, repeating step (b) until all of the nozzles but a central nozzle in each set have been fired, and then firing the central nozzle.

Optionally the printer controller is manufactured in accordance with a method of manufacturing a plurality of printhead modules, at least some of which are capable of being combined in pairs to form bilithic pagewidth printheads, the method comprising the step of laying out each of the plurality of printhead modules on a wafer substrate, wherein at least one of the printhead modules is right-handed and at least another is left-handed.

Optionally the printer controller supplies data to a printhead module including:
at least one row of print nozzles;

at least two shift registers for shifting in dot data supplied from a data source to each of the at least one rows, wherein each print nozzle obtains dot data to be fired from an element of one of the shift registers.

Optionally the printer controller is installed in a printer comprising:

a printhead comprising at least a first elongate printhead module, the at least one printhead module including at least one row of print nozzles for expelling ink; and at least first and second printer controllers configured to receive print data and process the print data to output dot data to the printhead, wherein the first and second printer controllers are connected to a common input of the printhead.

Optionally the printer controller is installed in a printer comprising:

a printhead comprising first and second elongate printhead modules, the printhead modules being parallel to each other and being disposed end to end on either side of a join region;

at least first and second printer controllers configured to receive print data and process the print data to output dot data to the printhead, wherein the fust printer controller outputs dot data only to the first printhead module and the second printer controller outputs dot data only to the second printhead module, wherein the printhead modules are configured such that no dot data passes between them.

Optionally the printer controller is installed in a printer comprising:

a printhead comprising first and second elongate printhead modules, the printhead modules being parallel to each other and being disposed end to end on either side of a join region, wherein the first printhead module is longer than the second printhead module;

at least first and second printer controllers configured to receive print data and process the print data to output dot data to the printhead, wherein: the first printer controller outputs dot data to both the first printhead module and the second printhead module; and the second printer controller outputs dot data only to the second printhead module.

Optionally the printer controller is installed in a printer comprising:

a printhead comprising first and second elongate printhead modules, the printhead modules being parallel to each other and being disposed end to end on either side of a join region, wherein the first printhead module is longer than the second printhead module;

at least first and second printer controllers configured to receive print data and process the print data to output dot data for the printhead, wherein: the first printer controller outputs dot data to both the first printhead module and the second controller; and the second printer controller outputs dot data to the second printhead module, wherein the dot data output by the second printer controller includes dot data it generates and at least some of the dot data received from the fust printer controller.

Optionally the piinter controller supplies dot data to at least one printhead module and at least partially compensating for errors in ink dot placement by at least one of a plurality of nozzles on the printhead module due to erroneous rotational displacement of the printhead module relative to a carrier, the printer being configured to:
access a correction factor associated with the at least one printhead module;

determine an order in which at least some of the dot data is supplied to at least one of the at least one printhead modules, the order being determined at least partly on the basis of the correction factor, thereby to at least partially compensate for the rotational displacement; and supply the dot data to the printhead module.

Optionally the printer controller supplies dot data to a printhead module having a plurality of nozzles for expelling ink, the printhead module including a plurality of thermal sensors, each of the thermal sensors being configured to respond to a temperature at or adjacent at least one of the nozzles, the printer controller being configured to modify operation of at least some of the nozzles in response to the temperature rising above a first threshold.
Optionally the printer controller controls a printhead comprising at least one monolithic printhead module, the at least one printhead module having a plurality of rows of nozzles configured to extend, in use, across at least part of a printable pagewidth of the printhead, the nozzles in each row being grouped into at least first and second fire groups, the printhead module being configured to sequentially fire, for each row, the nozzles of each fire group, such that each nozzle in the sequence from each fire group is fired simultaneously with respective corresponding nozzles in the sequence in the other fire groups, wherein the nozzles are fired row by row such that the nozzles of each row are all fired before the nozzles of each subsequent row, wherein the printer controller is configured to provide one or more control signals that control the order of firing of the nozzles.

Optionally the printer controller outputs to a printhead module:
dot data to be printed with at least two different inks; and control data for controlling printing of the dot data;

the printer controller including at least one communication output, each or the communication output being configured to output at least some of the control data and at least some of the dot data for the at least two inks.

Optionally the printer controller supplies data to a printhead module including at least one row of printhead nozzles, at least one row including at least one displaced row portion, the displacement of the row portion including a component in a direction normal to that of a pagewidth to be printed.

Optionally the printer controller supplies print data to at least one printhead module capable of printing a maximum of n of channels of print data, the at least one printhead module being configurable into:

a first mode, in which the printhead module is configured to receive data for a first number of the channels; and a second mode, in which the printhead module is configured to receive print data for a second number of the channels, wherein the first number is greater than the second number;

wherein the printer controller is selectively configurable to supply dot data for the first and second modes.
Optionally the printer controller supplies one or more control signals to a printhead module, the printhead module including at least one row that comprises a plurality of sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, such that:

(a) a fire signal is provided to nozzles at a first and nth position in each set of nozzles;
(b) a fire signal is provided to the next inward pair of nozzles in each set;

(c) in the event n is an even number, step (b) is repeated until all of the nozzles in each set has been fired;
and (d) in the event n is an odd number, step (b) is repeated until all of the nozzles but a central nozzle in each set have been fired, and then the central nozzle is fired.

Optionally the printer controller supplies one or more control signals to a printhead module, the printhead module including at least one row that comprises a plurality of adjacent sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, the method comprising providing, for each set of nozzles, a fire signal in accordance with the sequence: [nozzle position 1, nozzle position n, nozzle position 2, nozzle position (n-1), ... , nozzle position x], wherein nozzle position x is at or adjacent the centre of the set of nozzles.

Optionally the printer controller supplies dot data to a printhead module comprising at least first and second rows configured to print ink of a similar type or color, at least some nozzles in the first row being aligned with respective corresponding nozzles in the second row in a direction of intended media travel relative to the printhead, the printhead module being configurable such that the nozzles in the first and second pairs of rows are fired such that some dots output to print media are printed to by nozzles from the first pair of rows and at least some other dots output to print media are printed to by nozzles from the second pair of rows, the printer controller being configurable to supply dot data to the printhead module for printing.

Optionally the printer controller supplies dot data to at least one printhead module, the at least one printhead module comprising a plurality of rows, each of the rows comprising a plurality of nozzles for ejecting ink, wherein the printhead module includes at least first and second rows configured to print ink of a similar type or color, the printer controller being configured to supply the dot data to the at least one printhead module such that, in the event a nozzle in the first row is faulty, a corresponding nozzle in the second row prints an ink dot at a position on print media at or adjacent a position where the faulty nozzle would otherwise have printed it.
Optionally the printer controller receives first data and manipulating the first data to produce dot data to be printed, the print controller including at least two serial outputs for supplying the dot data to at least one printhead.
Optionally the printer controller supplies data to a printhead module including:

at least one row of print nozzles;

at least first and second shift registers for shifting in dot data supplied from a data source, wherein each shift register feeds dot data to a group of nozzles, and wherein each of the groups of the nozzles is interleaved with at least one of the other groups of the nozzles.

Optionally the printer controller supplies data to a printhead capable of printing a maximum of n of channels of print data, the printhead being configurable into:

a first mode, in which the printhead is configured to receive print data for a first number of the channels;
and a second mode, in which the printhead is configured to receive print data for a second number of the channels, wherein the first number is greater than the second number.

Optionally the printer controller supplies data to a printhead comprising a plurality of printhead modules, the printhead being wider than a reticle step used in fonning the modules, the printhead comprising at least two types of the modules, wherein each type is determined by its geometric shape in plan.

Optionally the printer controller supplies data to a printhead module including at least one row that comprises a plurality of sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, such that, for each set of nozzles, a fire signal is provided in accordance with the sequence: [nozzle position 1, nozzle position n, nozzle position 2, nozzle position (n-1), ... , nozzle position x], wherein nozzle position x is at or adjacent the centre of the set of nozzles.

Optionally the printer controller supplies data to a printhead module including at least one row that comprises a plurality of adjacent sets of n adjacent nozzles, each of the nozzles being configured to expel the ink in response to a fire signal, the printhead being configured to output ink from nozzles at a first and nth position in each set of nozzles, and then each next inward pair of nozzles in each set, until:

in the event n is an even number, all of the nozzles in each set has been fired; and in the event n is an odd number, all of the nozzles but a central nozzle in each set have been fired, and then to fire the central nozzle.

Optionally the printer controller supplies data to a printhead module for receiving dot data to be printed using at least two different inks and control data for controlling printing of the dot data, the printhead module including a communication input for receiving the dot data for the at least two colors and the control data.

Optionally the printer controller supplies data to a printhead module including at least one row of printhead nozzles, at least one row including at least one displaced row portion, the displacement of the row portion including a component in a direction normal to that of a pagewidth to be printed.

Optionally the printer controller supplies data to a printhead module having a plurality of rows of nozzles configured to extend, in use, across at least part of a printable pagewidth, the nozzles in each row being grouped into at least first and second fire groups, the printhead module being configured to sequentially fire, for each row, the nozzles of each fire group, such that each nozzle in the sequence from each fire group is fired simultaneously with respective corresponding nozzles in the sequence in the other fire groups, wherein the nozzles are fired row by row such that the nozzles of each row are all fired before the nozzles of each subsequent row.

Optionally the printer controller supplies data to a printhead module comprising at least first and second rows configured to print ink of a similar type or color, at least some nozzles in the first row being aligned with respective corresponding nozzles in the second row in a direction of intended media travel relative to the printhead, the printhead module being configurable such that the nozzles in the first and second pairs of rows are fired such that some dots output to print media are printed to by nozzles from the first pair of rows and at least some other dots output to print media are printed to by nozzles from the second pair of rows.

Optionally the printer controller supplies data to a printhead module that includes:
at least one row of print nozzles;

at least first and second shift registers for shifting in dot data supplied from a data source, wherein each shift register feeds dot data to a group of nozzles, and wherein each of the groups of the nozzles is interleaved with at least one of the other groups of the nozzles.

Optionally the printer controller supplies data to a printhead module having a plurality of nozzles for expelling ink, the printhead module including a plurality of thermal sensors, each of the thermal sensors being configured to respond to a temperature at or adjacent at least one of the nozzles, the printhead module being configured to modify operation of the nozzles in response to the temperature rising above a first threshold.

Optionally the printer controller supplies data to a printhead module comprising a plurality of rows, each of the rows comprising a plurality of nozzles for ejecting ink, wherein the printhead module includes at least first and second rows configured to print ink of a similar type or color, and being configured such that, in the event a nozzle in the first row is faulty, a corresponding nozzle in the second row prints an ink dot at a position on print media at or adjacent a position where the faulty nozzle would otherwise have printed it.

In a seventeenth aspect the present invention provides printer controller for supplying one or more control signals to a printhead module, the printhead module including at least one row that comprises a plurality of sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, such that:

(a) a fire signal is provided to nozzles at a first and nth position in each set of nozzles;
(b) a fire signal is provided to the next inward pair of nozzles in each set;

(c) in the event n is an even number, step (b) is repeated until all of the nozzles in each set has been fired;
and (d) in the event n is an odd number, step (b) is repeated until all of the nozzles but a central nozzle in each set have been fired, and then the central nozzle is fired.

Optionally the printhead module includes a plurality of the rows of nozzles, the printer controller being configured to control the printhead module such that steps (a) to (d) are repeated for each of the rows of nozzles.

Optionally the rows are disposed in pairs.

Optionally the rows in each pair of rows are offset relative to each other.
Optionally each pair of rows is configured to print the same color ink.
Optionally each pair of rows is connected to a common ink source.

Optionally the sets of nozzles are adjacent each other.

Optionally the sets of nozzles are separated by an intermediate nozzle, the intermediate nozzle being fired either prior to the nozzle at position 1 in each set, or following the nozzle at position n.

Optionally the printhead module is one of a plurality of printhead modules that form a pagewidth printhead, the printer controller being configure to supply the control signals to at least a plurality of the printhead modules.

Optionally the printer controller is for implementing a method of at least partially compensating for errors in ink dot placement by at least one of a plurality of nozzles due to erroneous rotational displacement of a printhead module relative to a carrier, the nozzles being disposed on the printhead module, the method comprising the steps of:

(a) determining the rotational displacement;

(b) determining at least one correction factor that at least partially compensates for the ink dot displacement;
and (c) using the correction factor to alter the output of the ink dots to at least partially compensate for the rotatidnal displacement.

Optionally the printer controller is for implementing a method of expelling ink from a printhead module including at least one row that comprises a plurality of adjacent sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, the method comprising providing, for each set of nozzles, a fire signal in accordance with the sequence: [nozzle position 1, nozzle position n, nozzle position 2, nozzle position (n-1), ... , nozzle position x], wherein nozzle position x is at or adjacent the centre of the set of nozzles.
Optionally the printer controller is for implementing a method of expelling ink from a printhead module including at least one row that comprises a plurality of sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, the method comprising the steps of:

(a) providing a fire signal to nozzles at a first and nth position in each set of nozzles;
(b) providing a fire signal to the next inward pair of nozzles in each set;

(c) in the event n is an even number, repeating step (b) until all of the nozzles in each set has been fired; and (d) in the event n is an odd number, repeating step (b) until all of the nozzles but a central nozzle in each set have been fired, and then firing the central nozzle.

Optionally the printer controller is manufactured in accordance with a method of manufacturing a plurality of printhead modules, at least some of which are capable of being combined in pairs to form bilithic pagewidth printheads, the method comprising the step of laying out each of the plurality of printhead modules on a wafer substrate, wherein at least one of the printhead modules is right-handed and at least another is left-handed.

Optionally the printer controller supplies data to a printhead module including:

at least one row of print nozzles;

at least two shift registers for shifting in dot data supplied from a data source to each of the at least one rows, wherein each print nozzle obtains dot data to be fired from an element of one of the shift registers.

Optionally the printer controller is installed in a printer comprising:

a printhead comprising at least a first elongate printhead module, the at least one printhead module including at least one row of print nozzles for expelling ink; and at least first and second printer controllers configured to receive print data and process the print data to output dot data to the printhead, wherein the first and second printer controllers are connected to a common input of the printhead.

Optionally the printer controller is installed in a printer comprising:

a printhead comprising first and second elongate printhead modules, the printhead modules being parallel to each other and being disposed end to end on either side of a join region;

at least first and second printer controllers configured to receive print data and process the print data to output dot data to the printhead, wherein the first printer controller outputs dot data only to the first printhead module and the second printer controller outputs dot data only to the second printhead module, wherein the printhead modules are configured such that no dot data passes between them.

Optionally the printer controller is installed in a printer comprising:

a printhead comprising first and second elongate printhead modules, the printhead modules being parallel to each other and being disposed end to end on either side of a join region, wherein the first printhead module is longer than the second printhead module;

at least first and second printer controllers configured to receive print data and process the print data to output dot data to the printhead, wherein: the first printer controller outputs dot data to both the first printhead module and the second printhead module; and the second printer controller outputs dot data only to the second printhead module.

Optionally the printer controller is installed in a printer comprising:

a printhead comprising first and second elongate printhead modules, the printhead modules being parallel to each other and being disposed end to end on either side of a join region, wherein the first printhead module is longer than the second printhead module;

at least first and second printer controllers configured to receive print data and process the,print data to output dot data for the printhead, wherein: the first printer controller outputs dot data to both the first printhead module and the second controller; and the second printer controller outputs dot data to the second printhead module, wherein the dot data output by the second printer controller includes dot data it generates and at least some of the dot data received from the first printer controller.

Optionally the printer controller supplies dot data to at least one printhead module and at least partially compensating for errors in ink dot placement by at least one of a plurality of nozzles on the printhead module due to erroneous rotational displacement of the printhead module relative to a carrier, the printer being configured to:
access a correction factor associated with the at least one printhead module;

determine an order in which at least some of the dot data is supplied to at least one of the at least one printhead modules, the order being determined at least partly on the basis of the con:ection factor, thereby to at least partially compensate for the rotational displacement; and supply the dot data to the printhead module.

Optionally the printer controller supplies dot data to a printhead module having a plurality of nozzles for expelling ink, the printhead module including a plurality of thermal sensors, each of the thermal sensors being configured to respond to a temperature at or adjacent at least one of the nozzles, the printer controller being configured to modify operation of at least some of the nozzles in response to the temperature rising above a first threshold.
Optionally the printer controller controls a printhead comprising at least one monolithic printhead module, the at least one printhead module having a plurality of rows of nozzles configured to extend, in use, across at least part of a printable pagewidth of the printhead, the nozzles in each row being grouped into at least first and second fire groups, the printhead module being configured to sequentially fire, for each row, the nozzles of each fire group, such that each nozzle in the sequence from each fire group is fired simultaneously with respective corresponding nozzles in the sequence in the other fire groups, wherein the nozzles are fired row by row such that the nozzles of each row are all fired before the nozzles of each subsequent row, wherein the printer controller is configured to provide one or more control signals that control the order of firing of the nozzles.

Optionally the printer controller outputs to a printhead module:

dot data to be printed with at least two different inks; and control data for controlling printing of the dot data;

the printer controller including at least one communication output, each or the communication output being configured to output at least some of the control data and at least some of the dot data for the at least two inks.

Optionally the printer controller supplies data to a printhead module including at least one row of printhead nozzles, at least one row including at least one displaced row portion, the displacement of the row portion including a component in a direction normal to that of a pagewidth to be printed.

Optionally the printer controller supplies print data to at least one printhead module capable of printing a maximum of n of channels of print data, the at least one printhead module being configurable into:

a first mode, in which the printhead module is configured to receive data for a first number of the channels; and a second mode, in which the printhead module is configured to receive print data for a second number of the channels, wherein the first number is greater than the second number;

wherein the printer controller is selectively configurable to supply dot data for the first and second modes.
Optionally the printer controller supplies data to a printhead comprising a plurality of printhead modules, the printhead being wider than a reticle step used in forming the modules, the printhead comprising at least two types of the modules, wherein each type is determined by its geometric shape in plan.

Optionally the printer controller supplies one or more control signals to a printhead module, the printhead module including at least one row that comprises a plurality of adjacent sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, the method comprising providing, for each set of nozzles, a fire signal in accordance with the sequence: [nozzle position 1, nozzle position n, nozzle position 2, nozzle position (n-1), ... , nozzle position x], wherein nozzle position x is at or adjacent the centre of the set of nozzles.

Optionally the printer controller supplies dot data to a printhead module comprising at least first and second rows configured to print ink of a similar type or color, at least some nozzles in the first row being aligned with respective corresponding nozzles in the second row in a direction of intended media travel relative to the printhead, the printhead module being configurable such that the nozzles in the first and second pairs of rows are fired such that some dots output to print media are printed to by nozzles from the first pair of rows and at least some other dots output to print media are printed to by nozzles from the second pair of rows, the printer controller being configurable to supply dot data to the printhead module for printing.

Optionally the printer controller supplies dot data to at least one printhead module, the at least one printhead module comprising a plurality of rows, each of the rows comprising a plurality of nozzles for ejecting ink, wherein the printhead module includes at least first and second rows configured to print ink of a similar type or color, the printer controller being configured to supply the dot data to the at least one printhead module such that, in the event a nozzle in the first row is faulty, a corresponding nozzle in the second row prints an ink dot at a position on print media at or adjacent a position where the faulty nozzle would otherwise have printed it.
Optionally the printer controller receives first data and manipulating the first data to produce dot data to be printed, the print controller including at least two serial outputs for supplying the dot data to at least one printhead.

Optionally the printer controller supplies data to a printhead module including:
at least one row of print nozzles;

at least first and second shift registers for shifting in dot data supplied from a data source, wherein each shift register feeds dot data to a group of nozzles, and wherein each of the groups of the nozzles is interleaved with at least one of the other groups of the nozzles.

Optionally the printer controller supplies data to a printhead capable of printing a maximum of n of channels of print data, the printhead being configurable into:

a first mode, in which the printhead is configured to receive print data for a first number of the channels;
and a second mode, in which the printhead is configured to receive print data for a second number of the channels, wherein the first number is greater than the second number.

Optionally the printer controller supplies data to a printhead comprising a plurality of printhead modules, the printhead being wider than a reticle step used in forming the modules, the printhead comprising at least two types of the modules, wherein each type is determined by its geometric shape in plan.

Optionally the printer controller supplies data to a printhead module including at least one row that comprises a plurality of sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, such that, for each set of nozzles, a fire signal is provided in accordance with the sequence: [nozzle position 1, nozzle position n, nozzle position 2, nozzle position (n-1), ... , nozzle position x], wherein nozzle position x is at or adjacent the centre of the set of nozzles.

Optionally the printer controller supplies data to a printhead module including at least one row that comprises a plurality of adjacent sets of n adjacent nozzles, each of the nozzles being configured to expel the ink in response to a fire signal, the printhead being configured to output ink from nozzles at a first and nth position in each set of nozzles, and then each next inward pair of nozzles in each set, until:

in the event n is an even number, all of the nozzles in each set has been fired; and in the event n is an odd number, all of the nozzles but a central nozzle in each set have been fired, and then to fire the central nozzle.

Optionally the printer controller supplies data to a printhead module for receiving dot data to be printed using at least two different inks and control data for controlling printing of the dot data, the printhead module including a communication input for receiving the dot data for the at least two colors and the control data.

Optionally the printer controller supplies data to a printhead module including at least one row of printhead nozzles, at least one row including at least one displaced row portion, the displacement of the row portion including a component in a direction normal to that of a pagewidth to be printed.

Optionally the printer controller supplies data to a printhead module having a plurality of rows of nozzles configured to extend, in use, across at least part of a printable pagewidth, the nozzles in each row being grouped into at least first and second fire groups, the printhead module being configured to sequentially fire, for each row, the nozzles of each fire group, such that each nozzle in the sequence from each fire group is fired simultaneously with respective corresponding nozzles in the sequence in the other fire groups, wherein the nozzles are fired row by row such that the nozzles of each row are all fired before the nozzles of each subsequent row.

Optionally the printer controller supplies data to a printhead module comprising at least first and second rows configured to print ink of a similar type or color, at least some nozzles in the first row being aligned with respective corresponding nozzles in the second row in a direction of intended media travel relative to the printhead, the printhead module being configurable such that the nozzles in the first and second pairs of rows are fired such that some dots output to print media are printed to by nozzles from the first pair of rows and at least some other dots output to print media are printed to by nozzles from the second pair of rows.

Optionally the printer controller supplies data to a printhead module that includes:
at least one row of print nozzles;

at least first and second shift registers for shifting in dot data supplied from a data source, wherein each shift register feeds dot data to a group of nozzles, and wherein each of the groups of the nozzles is interleaved with at least one of the other groups of the nozzles.

Optionally the printer controller supplies data to a printhead module having a plurality of nozzles for expelling ink, the printhead module including a plurality of thermal sensors, each of the thermal sensors being configured to respond to a temperature at or adjacent at least one of the nozzles, the printhead module being configured to modify operation of the nozzles in response to the temperature rising above a first threshold.

Optionally the printer controller supplies data to a printhead module comprising a plurality of rows, each of the rows comprising a plurality of nozzles for ejecting ink, wherein the printhead module includes at least first and second rows configured to print ink of a similar type or color, and being configured such that, in the event a nozzle in the first row is faulty, a corresponding nozzle in the second row prints an ink dot at a position on print media at or adjacent a position where the faulty nozzle would otherwise have printed it.

Optionally the printhead module includes a plurality of the rows, the printer controller being configured to cause firing of each nozzle in each row simultaneously with the nozzle or nozzles at the same position in the other rows.
Optionally the printer controller includes a plurality of pairs of the rows, each pair of rows including an odd row and an even row, the odd and even rows in each pair being offset from each other in both x and y directions relative to an intended direction of print media movement relative to the printhead, the printer controller being configured to control the at least one printhead module to cause firing of at least a plurality of the odd rows prior to firing any of the even rows, or vice versa.

Optionally all the odd rows are fired before any of the even rows are fired, or vice versa.

Optionally the printer controller is configured to control the printhead such that the odd rows, or the even rows, or both, are fired in a predetermined order.

Optionally the printer controller is configurable such that the predetermined order is selectable from a plurality of predetermined available orders.

Optionally the predetermined order is sequential.

Optionally the printer controller is configurable such that the predetermined order can commence at any of a plurality of the rows.

In an eighteenth aspect the present invention provides printer controller for supplying one or more control signals to a printhead module, the printhead module including at least one row that comprises a plurality of adjacent sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, the method comprising providing, for each set of nozzles, a fire signal in accordance with the sequence: [nozzle position 1, nozzle position n, nozzle position 2, nozzle position (n-1), ... , nozzle position x], wherein nozzle position x is at or adjacent the centre of the set of nozzles.

Optionally the printer controller is configured to cause the nozzle at each given position within the set to be fired simultaneously with the nozzles in the other sets at respective corresponding positions.

Optionally the printhead module includes a plurality of the rows of nozzles, the printer controller being configured to control the printhead module such that the steps are repeated for each of the rows of nozzles.

Optionally the rows are disposed in pairs.

Optionally the rows in each pair of rows are offset relative to each other.
Optionally each pair of rows is configured to print the same color ink.

Optionally each pair of rows is connected to a common ink source.

Optionally the sets of nozzles are adjacent each other.

Optionally the sets of nozzles are separated by an intermediate nozzle, the intermediate nozzle being fired either prior to the nozzle at position 1 in each set, or following the nozzle at position n.

Optionally the printhead module is one of a plurality of printhead modules that form a pagewidth printhead, the printer controller being configure to supply the control signals to at least a plurality of the printhead modules.

Optionally the printer controller is for implementing a method of expelling ink from a printhead module including at least one row that comprises a plurality of sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, the method comprising the steps of:

(a) providing a fire signal to nozzles at a first and nth position in each set of nozzles;
(b) providing a fire signal to the next inward pair of nozzles in each set;

(c) in the event n is an even number, repeating step (b) until all of the nozzles in each set has been fired; and (d) in the event n is an odd number, repeating step (b) until all of the nozzles but a central nozzle in each set have been fired, and then firing the central nozzle.

Optionally the printer controller is manufactured in accordance with a method of manufacturing a plurality of printhead modules, at least some of which are capable of being combined in pairs to form bilithic pagewidth printheads, the method comprising the step of laying out each of the plurality of printhead modules on a wafer substrate, wherein at least one of the printhead modules is right-handed and at least another is left-handed.

Optionally the printer controller supplies data to a printhead module including:
at least one row of print nozzles;

at least two shift registers for shifting in dot data supplied from a data source to each of the at least one rows, wherein each print nozzle obtains dot data to be fired from an element of one of the shift registers.

Optionally the printer controller is installed in a printer comprising:

a printhead comprising at least a first elongate printhead module, the at least one printhead module including at least one row of print nozzles for expelling ink; and at least first and second printer controllers configured to receive print data and process the print data to output dot data to the printhead, wherein the first and second printer controllers are connected to a common input of the printhead.

Optionally the printer controller is installed in a printer comprising:

a printhead comprising first and second elongate printhead modules, the printhead modules being parallel to each other and being disposed end to end on either side of a join region;

at least first and second printer controllers configured to receive print data and process the print data to output dot data to the printhead, wherein the first printer controller outputs dot data only to the first printhead module and the second printer controller outputs dot data only to the second printhead module, wherein the printhead modules are configured such that no dot data passes between them.

Optionally the printer controller is installed in a printer comprising:

a printhead comprising first and second elongate printhead modules, the printhead modules being parallel to each other and being disposed end to end on either side of a join region, wherein the first printhead module is longer than the second printhead module;

at least first and second printer controllers configured to receive print data and process the print data to output dot data to the printhead, wherein: the first printer controller outputs dot data to both the first printhead module and the second printhead module; and the second printer controller outputs dot data only to the second printhead module.

Optionally the printer controller is installed in a printer comprising:

a printhead comprising first and second elongate printhead modules, the printhead modules being parallel to each other and being disposed end to end on either side of a join region, wherein the first printhead module is longer than the second printhead module;

at least first and second printer controllers configured to receive print data and process the print data to output dot data for the printhead, wherein: the first printer controller outputs dot data to both the first printhead module and the second controller; and the second printer controller outputs dot data to the second printhead module, wherein the dot data output by the second printer controller includes dot data it generates and at least some of the dot data received from the first printer controller.

Optionally the printer controller supplies dot data to at least one printhead module and at least partially compensating for errors in ink dot placement by at least one of a plurality of nozzles on the printhead module due to erroneous rotational displacement of the printhead module relative to a carrier, the printer being configured to:

access a correction factor associated with the at least one printhead module;

determine an order in which at least some of the dot data is supplied to at least one of the at least one printhead modules, the order being determined at least partly on the basis of the correction factor, thereby to at least partially compensate for the rotational displacement; and supply the dot data to the printhead module.

Optionally the printer controller supplies dot data to a printhead module having a plurality of nozzles for expelling ink, the printhead module including a plurality of thermal sensors, each of the thermal sensors being configured to respond to a temperature at or adjacent at least one of the nozzles, the printer controller being configured to modify operation of at least some of the nozzles in response to the temperature rising above a first threshold.

Optionally the printer controller controls a printhead comprising at least one monolithic printhead module, the at least one printhead module having a plurality of rows of nozzles configured to extend, in use, across at least part of a printable pagewidth of the printhead, the nozzles in each row being grouped into at least first and second fire groups, the printhead module being configured to sequentially fire, for each row, the nozzles of each fire group, such that each nozzle in the sequence from each fire group is fired simultaneously with respective corresponding nozzles in the sequence in the other fire groups, wherein the nozzles are fired row by row such that the nozzles of each row are all fired before the nozzles of each subsequent row, wherein the printer controller is configured to provide one or more control signals that control the order of firing of the nozzles.

Optionally the printer controller outputs to a printhead module:
dot data to be printed with at least two different inks; and control data for controlling printing of the dot data;

the printer controller including at least one communication output, each or the communication output being configured to output at least some of the control data and at least some of the dot data for the at least two inks.

Optionally the printer controller supplies data to a printhead module including at least one row of printhead nozzles, at least one row including at least one displaced row portion, the displacement of the row portion including a component in a direction normal to that of a pagewidth to be printed.

Optionally the printer controller supplies print data to at least one printhead module capable of printing a maximum of n of channels of print data, the at least one printhead module being configurable into:

a first mode, in which the printhead module is configured to receive data for a first number of the channels; and a second mode, in which the printhead module is configured to receive print data for a second number of the channels, wherein the first number is greater than the second number;

wherein the printer controller is selectively configurable to supply dot data for the first and second modes.
Optionally the printer controller supplies data to a printhead comprising a plurality of printhead modules, the printhead being wider than a reticle step used in forming the modules, the printhead comprising at least two types of the modules, wherein each type is determined by its geometric shape in plan.

Optionally the printer controller supplies one or more control signals to a printhead module, the printhead module including at least one row that comprises a plurality of adjacent sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, the method comprising providing, for each set of nozzles, a fire signal in accordance with the sequence: [nozzle position 1, nozzle position n, nozzle position 2, nozzle position (n-1), ... , nozzle position x], wherein nozzle position x is at or adjacent the centre of the set of nozzles.

Optionally the printer controller supplies dot data to a printhead module comprising at least first and second rows configured to print ink of a similar type or color, at least some nozzles in the first row being aligned with respective corresponding nozzles in the second row in a direction of intended media travel relative to the printhead, the printhead module being configurable such that the nozzles in the first and second pairs of rows are fired such that some dots output to print media are printed to by nozzles from the first pair of rows and at least some other dots output to print media are printed to by nozzles from the second pair of rows, the printer controller being configurable to supply dot data to the printhead module for printing.

Optionally the printer controller supplies dot data to at least one printhead module, the at least one printhead module comprising a plurality of rows, each of the rows comprising a plurality of nozzles for ejecting ink, wherein the printhead module includes at least first and second rows configured to print ink of a similar type or color, the printer controller being configured to supply the dot data to the at least one printhead module such that, in the event a nozzle in the first row is faulty, a corresponding nozzle in the second row prints an ink dot at a position on print media at or adjacent a position where the faulty nozzle would otherwise have printed it.
Optionally the printer controller receives first data and manipulating the first data to produce dot data to be printed, the print controller including at least two serial outputs for supplying the dot data to at least one printhead.

Optionally the printer controller supplies data to a printhead module including:
at least one row of print nozzles;

at least first and second shift registers for shifting in dot data supplied from a data source, wherein each shift register feeds dot data to a group of nozzles, and wherein each of the groups of the nozzles is interleaved with at least one of the other groups of the nozzles.

Optionally the printer controller supplies data to a printhead capable of printing a maximum of n of channels of print data, the printhead being configurable into:

a first mode, in which the printhead is configured to receive print data for a first number of the channels;
and a second mode, in which the printhead is configured to receive print data for a second number of the channels, wherein the first number is greater than the second number.

Optionally the printer controller supplies data to a printhead comprising a plurality of printhead modules, the printhead being wider than a reticle step used in forming the modules, the printhead comprising at least two types of the modules, wherein each type is determined by its geometric shape in plan.

Optionally the printer controller supplies data to a printhead module including at least one row that comprises a plurality of sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, such that, for each set of nozzles, a fire signal is provided in accordance with the sequence: [nozzle position 1, nozzle position n, nozzle position 2, nozzle position (n-1), ... , nozzle position x], wherein nozzle position x is at or adjacent the centre of the set of nozzles.

Optionally the printer controller supplies data to a printhead module including at least one row that comprises a plurality of adjacent sets of n adjacent nozzles, each of the nozzles being configured to expel the ink in response to a fire signal, the printhead being configured to output ink from nozzles at a first and nth position in each set of nozzles, and then each next inward pair of nozzles in each set, until:

in the event n is an even number, all of the nozzles in each set has been fired; and in the event n is an odd number, all of the nozzles but a central nozzle in each set have been fired, and then to fire the central nozzle.

Optionally the printer controller supplies data to a printhead module for receiving dot data to be printed using at least two different inks and control data for controlling printing of the dot data, the printhead module including a communication input for receiving the dot data for the at least two colors and the control data.

Optionally the printer controller supplies data to a printhead module including at least one row of printhead nozzles, at least one row including at least one displaced row portion, the displacement of the row portion including a component in a direction normal to that of a pagewidth to be printed.

Optionally the printer controller supplies data to a printhead module having a plurality of rows of nozzles configured to extend, in use, across at least part of a printable pagewidth, the nozzles in each row being grouped into at least first and second fire groups, the printhead module being configured to sequentially fire, for each row, the nozzles of each fire group, such that each nozzle in the sequence from each fire group is fired simultaneously with respective corresponding nozzles in the sequence in the other fire groups, wherein the nozzles are fired row by row such that the nozzles of each row are all fired before the nozzles of each subsequent row.

Optionally the printer controller supplies data to a printhead module comprising at least first and second rows configured to print ink of a similar type or color, at least some nozzles in the first row being aligned with respective corresponding nozzles in the second row in a direction of intended media travel relative to the printhead, the printhead module being configurable such that the nozzles in the first and second pairs of rows are fired such that some dots output to print media are printed to by nozzles from the first pair of rows and at least some other dots output to print media are printed to by nozzles from the second pair of rows.

Optionally the printer controller supplies data to a printhead module that includes:

at least one row of print nozzles;

at least first and second shift registers for shifting in dot data supplied from a data source, wherein each shift register feeds dot data to a group of nozzles, and wherein each of the groups of the nozzles is interleaved with at least one of the other groups of the nozzles.

Optionally the printer controller supplies data to a printhead module having a plurality of nozzles for expelling ink, the printhead module including a plurality of thermal sensors, each of the thermal sensors being configured to respond to a temperature at or adjacent at least one of the nozzles, the printhead module being configured to modify operation of the nozzles in response to the temperature rising above a first threshold.

Optionally the printer controller supplies data to a printhead module comprising a plurality of rows, each of the rows comprising a plurality of nozzles for ejecting ink, wherein the printhead module includes at least first and second rows configured to print ink of a similar type or color, and being configured such that, in the event a nozzle in the first row is faulty, a corresponding nozzle in the second row prints an ink dot at a position on print media at or adjacent a position where the faulty nozzle would otherwise have printed it.

Optionally the printhead module includes a plurality of the rows, the printer controller being configured to cause firing of each nozzle in each row simultaneously with the nozzle or nozzles at the same position in the other rows.
Optionally the printer controller includes a plurality of pairs of the rows, each pair of rows including an odd row and an even row, the odd and even rows in each pair being offset from each other in both x and y directions relative to an intended direction of print media movement relative to the printhead, the printer controller being configured to control the at least one printhead module to cause firing of at least a plurality of the odd rows prior to firing any of the even rows, or vice versa.

Optionally all the odd rows are fired before any of the even rows are fired, or vice versa.

Optionally the printer controller is configured to control the printhead such that the odd rows, or the even rows, or both, are fired in a predetermined order.

Optionally the printer controller is configurable such that the predetermined order is selectable from a plurality of predetermined available orders.

Optionally the predetermined order is sequential.

Optionally the printer controller is configurable such that the predetermined order can commence at any of a plurality of the rows.

In a nineteenth aspect the present invention provides a printer controller for supplying dot data to a printhead module comprising at least first and second rows configured to print ink of a similar type or color, at least some nozzles in the fust row being aligned with respective corresponding nozzles in the second row in a direction of intended media travel relative to the printhead, the printhead module being configurable such that the nozzles in the first and second pairs of rows are fired such that some dots output to print media are printed to by nozzles from the first pair of rows and at least some other dots output to print media are printed to by nozzles from the second pair of rows, the printer controller being configurable to supply dot data to the printhead module for printing.

Optionally print engine comprising a printer controller for supplying dot data to a printhead module comprising at least first and second rows configured to print ink of a similar type or color, at least some nozzles in the first row being aligned with respective corresponding nozzles in the second row in a direction of intended media travel relative to the printhead, the printhead module being configurable such that the nozzles in the first and second pairs of rows are fired such that some dots output to print media are printed to by nozzles from the first pair of rows and at least some other dots output to print media are printed to by nozzles from the second pair of rows, the printer controller being configurable to supply dot data to the printhead module for printing; and a printhead module, wherein the printhead module is controllable such that either of the nozzles in each aligned pair of nozzles in the first and second rows can be selected to output ink for a selected dot to be printed on the print media.

Optionally in the event a nozzle in the first row is faulty, the corresponding nozzle in the second row is selected to output ink for a dot for which the faulty nozzle would otherwise have output ink.

Optionally the print engine includes a plurality of sets of the first and second rows.

Optionally each of the sets of the first and second rows is configured to print in a single color or ink type.

Optionally the first and second rows in at least one of the sets are separated by one or more rows from the other set or sets.

Optionally each of the rows includes an odd sub-row and an even sub-row, the odd and even sub-rows being offset with respect to each other in a direction of intended print media travel relative to the printhead.
Optionally the odd and even sub-rows are transversely offset relative to each other.

Optionally the print engine is configured such that the first and second rows are fired alternately.
Optionally the print engine comprises a plurality of the printhead modules.

Optionally a printer including a printer controller for supplying dot data to a printhead module comprising at least first and second rows configured to print ink of a similar type or color, at least some nozzles in the first row being aligned with respective corresponding nozzles in the second row in a direction of intended media travel relative to the printhead, the printhead module being configurable such that the nozzles in the first and second pairs of rows are fired such that some dots output to print media are printed to by nozzles from the first pair of rows and at least some other dots output to print media are printed to by nozzles from the second pair of rows, the printer controller being configurable to supply dot data to the printhead module for printing.

Optionally a printer including a print engine comprising a printer controller for supplying dot data to a printhead module comprising at least first and second rows configured to print ink of a similar type or color, at least some nozzles in the first row being aligned with respective corresponding nozzles in the second row in a direction of intended media travel relative to the printhead, the printhead module being configurable such that the nozzles in the first and second pairs of rows are fired such that some dots output to print media are printed to by nozzles from the first pair of rows and at least some other dots output to print media are printed to by nozzles from the second pair of rows, the printer controller being configurable to supply dot data to the printhead module for printing; and a printhead module, wherein the printhead module is controllable such that either of the nozzles in each aligned pair of nozzles in the first and second rows can be selected to output ink for a selected dot to be printed on the print media.

Optionally the printer controller is for implementing a method of expelling ink from a printhead module including at least one row that comprises a plurality of sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, the method comprising the steps of:

(a) providing a fire signal to nozzles at a first and nth position in each set of nozzles;
(b) providing a fire signal to the next inward pair of nozzles in each set;

(c) in the event n is an even number, repeating step (b) until all of the nozzles in each set has been fired; and (d) in the event n is an odd number, repeating step (b) until all of the nozzles but a central nozzle in each set have been fired, and then firing the central nozzle.

Optionally the printer controller is manufactured in accordance with a method of manufacturing a plurality of printhead modules, at least some of which are capable of being combined in pairs to form bilithic pagewidth printheads, the method comprising the step of laying out each of the plurality of printhead modules on a wafer substrate, wherein at least one of the printhead modules is right-handed and at least another is left-handed.

Optionally the printer controller supplies data to a printhead module including:
at least one row of print nozzles;

at least two shift registers for shifting in dot data supplied from a data source to each of the at least one rows, wherein each print nozzle obtains dot data to be fired from an element of one of the shift registers.

Optionally the printer controller is installed in a printer comprising:

a printhead comprising at least a first elongate printhead module, the at least one printhead module including at least one row of print nozzles for expelling ink; and at least first and second printer controllers configured to receive print data and process the print data to output dot data to the printhead, wherein the first and second printer controllers are connected to a common input of the printhead.

Optionally the printer controller is installed in a printer comprising:

a printhead comprising first and second elongate printhead modules, the printhead modules being parallel to each other and being disposed end to end on either side of a join region;

at least first and second printer controllers configured to receive print data and process the print data to output dot data to the printhead, wherein the first printer controller outputs dot data only to the first printhead module and the second printer controller outputs dot data only to the second printhead module, wherein the printhead modules are configured such that no dot data passes between them.

Optionally the printer controller is installed in a printer comprising:

a printhead comprising first and second elongate printhead modules, the printhead modules being parallel to each other and being disposed end to end on either side of a join region, wherein the first printhead module is longer than the second printhead module;

at least first and second printer controllers configured to receive print data and process the print data to output dot data to the printhead, wherein: the first printer controller outputs dot data to both the fust printhead module and the second printhead module; and the second printer controller outputs dot data only to the second printhead module.

Optionally the printer controller is installed in a printer comprising:

a printhead comprising first and second elongate printhead modules, the printhead modules being parallel to each other and being disposed end to end on either side of a join region, wherein the first printhead module is longer than the second printhead module;

at least first and second printer controllers configured to receive print data and process the print data to output dot data for the printhead, wherein: the first printer controller outputs dot data to both the first printhead module and the second controller; and the second printer controller outputs dot data to the second printhead module, wherein the dot data output by the second printer controller includes dot data it generates and at least some of the dot data received from the first printer controller.

Optionally the printer controller supplies dot data to at least one printhead module and at least partially compensating for errors in ink dot placement by at least one of a plurality of nozzles on the printhead module due to erroneous rotational displacement of the printhead module relative to a carrier, the printer being configured to:
access a correction factor associated with the at least one printhead module;

determine an order in which at least some of the dot data is supplied to at least one of the at least one printhead modules, the order being determined at least partly on the basis of the correction factor, thereby to at least partially compensate for the rotational displacement; and supply the dot data to the printhead module.

Optionally the printer controller supplies dot data to a printhead module having a plurality of nozzles for expelling ink, the printhead module including a plurality of thermal sensors, each of the thermal sensors being configured to respond to a temperature at or adjacent at least one of the nozzles, the printer controller being configured to modify operation of at least some of the nozzles in response to the temperature rising above a first threshold.
Optionally the printer controller controls a printhead comprising at least one monolithic printhead module, the at least one printhead module having a plurality of rows of nozzles configured to extend, in use, across at least part of a printable pagewidth of the printhead, the nozzles in each row being grouped into at least first and second fire groups, the printhead module being configured to sequentially fire, for each row, the nozzles of each fire group, such that each nozzle in the sequence from each fire group is fired simultaneously with respective corresponding nozzles in the sequence in the other fire groups, wherein the nozzles are fired row by row such that the nozzles of each row are all fired before the nozzles of each subsequent row, wherein the printer controller is configured to provide one or more control signals that control the order of firing of the nozzles.

Optionally the printer controller outputs to a printhead module:
dot data to be printed with at least two different inks; and control data for controlling printing of the dot data;

the printer controller including at least one communication output, each or the communication output being configured to output at least some of the control data and at least some of the dot data for the at least two inks.
Optionally the printer controller supplies data to a printhead module including at least one row of printhead nozzles, at least one row including at least one displaced row portion, the displacement of the row portion including a component in a direction normal to that of a pagewidth to be printed.

Optionally the printer controller supplies print data to at least one printhead module capable of printing a maximum of n of channels of print data, the at least one printhead module being configurable into:

a first mode, in which the printhead module is configured to receive data for a first number of the channels; and a second mode, in which the printhead module is configured to receive print data for a second number of the channels, wherein the first number is greater than the second number;

wherein the printer controller is selectively configurable to supply dot data for the first and second modes.

Optionally the printer controller supplies data to a printhead comprising a plurality of printhead modules, the printhead being wider than a reticle step used in forming the modules, the printhead comprising at least two types of the modules, wherein each type is determined by its geometric shape in plan.

Optionally the printer controller supplies one or more control signals to a printhead module, the printhead module including at least one row that comprises a plurality of adjacent sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, the method comprising providing, for each set of nozzles, a fire signal in accordance with the sequence: [nozzle position 1, nozzle position n, nozzle position 2, nozzle position (n-1), ... , nozzle position x], wherein nozzle position x is at or adjacent the centre of the set of nozzles.

Optionally the printer controller supplies dot data to a printhead module comprising at least first and second rows configured to print ink of a similar type or color, at least some nozzles in the first row being aligned with respective corresponding nozzles in the second row in a direction of intended media travel relative to the printhead, the printhead module being configurable such that the nozzles in the first and second pairs of rows are fired such that some dots output to print media are printed to by nozzles from the first pair of rows and at least some other dots output to print media are printed to by nozzles from the second pair of rows, the printer controller being configurable to supply dot data to the printhead module for printing.

Optionally the printer controller supplies dot data to at least one printhead module, the at least one printhead module comprising a plurality of rows, each of the rows comprising a plurality of nozzles for ejecting ink, wherein the printhead module includes at least first and second rows configured to print ink of a similar type or color, the printer controller being configured to supply the dot data to the at least one printhead module such that, in the event a nozzle in the first row is faulty, a corresponding nozzle in the second row prints an ink dot at a position on print media at or adjacent a position where the faulty nozzle would otherwise have printed it.
Optionally the printer controller receives first data and manipulating the first data to produce dot data to be printed, the print controller including at least two serial outputs for supplying the dot data to at least one printhead.

Optionally the printer controller supplies data to a printhead module including:
at least one row of print nozzles;

at least first and second shift registers for shifting in dot data supplied from a data source, wherein each shift register feeds dot data to a group of nozzles, and wherein each of the groups of the nozzles is interleaved with at least one of the other groups of the nozzles.

Optionally the printer controller supplies data to a printhead capable of printing a maximum of n of channels of print data, the printhead being configurable into:

a first mode, in which the printhead is configured to receive print data for a first number of the channels;
and a second mode, in which the printhead is configured to receive print data for a second number of the channels, wherein the first number is greater than the second number.

Optionally the printer controller supplies data to a printhead comprising a plurality of printhead modules, the printhead being wider than a reticle step used in forming the modules, the printhead comprising at least two types of the modules, wherein each type is determined by its geometric shape in plan.

Optionally the printer controller supplies data to a printhead module including at least one row that comprises a plurality of sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, such that, for each set of nozzles, a fire signal is provided in accordance with the sequence: [nozzle position 1, nozzle position n, nozzle position 2, nozzle position (n-1), ... , nozzle position x], wherein nozzle position x is at or adjacent the centre of the set of nozzles.

Optionally the printer controller supplies data to a printhead module including at least one row that comprises a plurality of adjacent sets of n adjacent nozzles, each of the nozzles being configured to expel the ink in response to a fire signal, the printhead being configured to output ink from nozzles at a first and nth position in each set of nozzles, and then each next inward pair of nozzles in each set, until:

in the event n is an even number, all of the nozzles in each set has been fired; and in the event n is an odd number, all of the nozzles but a central nozzle in each set have been fired, and then to fire the central nozzle.

Optionally the printer controller supplies data to a printhead module for receiving dot data to be printed using at least two different inks and control data for controlling printing of the dot data, the printhead module including a communication input for receiving the dot data for the at least two colors and the control data.

Optionally the printer controller supplies data to a printhead module including at least one row of printhead nozzles, at least one row including at least one displaced row portion, the displacement of the row portion including a component in a direction normal to that of a pagewidth to be printed.

Optionally the printer controller supplies data to a printhead module having a plurality of rows of nozzles configured to extend, in use, across at least part of a printable pagewidth, the nozzles in each row being grouped into at least first and second fire groups, the printhead module being configured to sequentially fire, for each row, the nozzles of each fire group, such that each nozzle in the sequence from each fire group is fired simultaneously with respective corresponding nozzles in the sequence in the other fire groups, wherein the nozzles are fired row by row such that the nozzles of each row are all fired before the nozzles of each subsequent row.

Optionally the printer controller supplies data to a printhead module comprising at least first and second rows configured to print ink of a similar type or color, at least some nozzles in the first row being aligned with respective corresponding nozzles in the second row in a direction of intended media travel relative to the printhead, the printhead module being configurable such that the nozzles in the first and second pairs of rows are fired such that some dots output to print media are printed to by nozzles from the first pair of rows and at least some other dots output to print media are printed to by nozzles from the second pair of rows.

Optionally the printer controller supplies data to a printhead module that includes:
at least one row of print nozzles;

at least first and second shift registers for shifting in dot data supplied from a data source, wherein each shift register feeds dot data to a group of nozzles, and wherein each of the groups of the nozzles is interleaved with at least one of the other groups of the nozzles.

Optionally the printer controller supplies data to a printhead module having a plurality of nozzles for expelling ink, the printhead module including a plurality of thermal sensors, each of the thennal sensors being configured to respond to a temperature at or adjacent at least one of the nozzles, the printhead module being configured to modify operation of the nozzles in response to the temperature rising above a first threshold.

Optionally the printer controller supplies data to a printhead module comprising a plurality of rows, each of the rows comprising a plurality of nozzles for ejecting ink, wherein the printhead module includes at least first and second rows configured to print ink of a similar type or color, and being configured such that, in the event a nozzle in the first row is faulty, a corresponding nozzle in the second row prints an ink dot at a position on print media at or adjacent a position where the faulty nozzle would otherwise have printed it.

In a twentieth aspect the present invention provides a printer controller for supplying dot data to at least one printhead module, the at least one printhead module comprising a plurality of rows, each of the rows comprising a plurality of nozzles for ejecting ink, wherein the printhead module includes at least first and second rows configured to print ink of a similar type or color, the printer controller being configured to supply the dot data to the at least one printhead module such that, in the event a nozzle in the first row is faulty, a corresponding nozzle in the second row prints an ink dot at a position on print media at or adjacent a position where the faulty nozzle would otherwise have printed it.

Optionally a print engine comprising a printer controller for supplying dot data to at least one printhead module, the at least one printhead module comprising a plurality of rows, each of the rows comprising a plurality of nozzles for ejecting ink, wherein the printhead module includes at least first and second rows configured to print ink of a similar type or color, the printer controller being configured to supply the dot data to the at least one printhead module such that, in the event a nozzle in the first row is faulty, a corresponding nozzle in the second row prints an ink dot at a position on print media at or adjacent a position where the faulty nozzle would otherwise have printed it; and the at least one printhead module, wherein each nozzle in the first row is paired with a nozzle in the second row, such that each pair of nozzles is aligned in an intended direction of print media travel relative to the printhead module.

Optionally the print engine includes a plurality of sets of the first and second rows.

Optionally each of the sets of the first and second rows is configured to print in a single color or ink type.
Optionally each of the rows includes an odd and an even sub-row, the odd and even sub-rows being offset with respect to each other in a direction of print media travel relative to the printhead in use.

Optionally the odd and even sub-rows are transversely offset with respect to each other.

Optionally a printer including at least one printer controller for supplying dot data to at least one printhead module, the at least one printhead module comprising a plurality of rows, each of the rows comprising a plurality of nozzles for ejecting ink, wherein the printhead module includes at least first and second rows configured to print ink of a similar type or color, the printer controller being configured to supply the dot data to the at least one printhead module such that, in the event a nozzle in the first row is faulty, a corresponding nozzle in the second row prints an ink dot at a position on print media at or adjacent a position where the faulty nozzle would otherwise have printed it.

Optionally a printer includes at least one print engine comprising a printer controller for supplying dot data to at least one printhead module, the at least one printhead module comprising a plurality of rows, each of the rows comprising a plurality of nozzles for ejecting ink, wherein the printhead module includes at least first and second rows configured to print ink of a similar type or color, the printer controller being configured to supply the dot data to the at least one printhead module such that, in the event a nozzle in the fust row is faulty, a corresponding nozzle in the second row prints an ink dot at a position on print media at or adjacent a position where the faulty nozzle would otherwise have printed it; and the at least one printhead module, wherein each nozzle in the first row is paired with a nozzle in the second row, such that each pair of nozzles is aligned in an intended direction of print media travel relative to the printhead module.

Optionally the printer controller is for implementing a method of expelling ink from a printhead module including at least one row that comprises a plurality of sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, the method comprising the steps of:

(a) providing a fire signal to nozzles at a first and nth position in each set of nozzles;
(b) providing a fire signal to the next inward pair of nozzles in each set;

(c) in the event n is an even number, repeating step (b) until all of the nozzles in each set has been fired; and (d) in the event n is an odd number, repeating step (b) until all of the nozzles but a central nozzle in each set have been fired, and then firing the central nozzle.

Optionally the printer controller is manufactured in accordance with a method of manufacturing a plurality of printhead modules, at least some of which are capable of being combined in pairs to form bilithic pagewidth printheads, the method comprising the step of laying out each of the plurality of printhead modules on a wafer substrate, wherein at least one of the printhead modules is right-handed and at least another is left-handed.

Optionally the printer controller supplies data to a printhead module including:

at least one row of print nozzles;

at least two shift registers for shifting in dot data supplied from a data source to each of the at least one rows, wherein each print nozzle obtains dot data to be fired from an element of one of the shift registers.

Optionally the printer controller is installed in a printer comprising:

a printhead comprising at least a first elongate printhead module, the at least one printhead module including at least one row of print nozzles for expelling ink; and at least first and second printer controllers configured to receive print data and process the print data to output dot data to the printhead, wherein the first and second printer controllers are connected to a common input of the printhead.

Optionally the printer controller is installed in a printer comprising:

a printhead comprising first and second elongate printhead modules, the printhead modules being parallel to each other and being disposed end to end on either side of a join region;

at least first and second printer controllers configured to receive print data and process the print data to output dot data to the printhead, wherein the first printer controller outputs dot data only to the first printhead module and the second printer controller outputs dot data only to the second printhead module, wherein the printhead modules are configured such that no dot data passes between them.

Optionally the printer controller is installed in a printer comprising:

a printhead comprising first and second elongate printhead modules, the printhead modules being parallel to each other and being disposed end to end on either side of a join region, wherein the first printhead module is longer than the second printhead module;

at least first and second printer controllers configured to receive print data and process the print data to output dot data to the printhead, wherein: the first printer controller outputs dot data to both the first printhead module and the second printhead module; and the second printer controller outputs dot data only to the second printhead module.

Optionally the printer controller is installed in a printer comprising:

a printhead comprising first and second elongate printhead modules, the printhead modules being parallel to each other and being disposed end to end on either side of a join region, wherein the first printhead module is longer than the second printhead module;

at least first and second printer controllers configured to receive print data and process the print data to output dot data for the printhead, wherein: the first printer controller outputs dot data to both the fust printhead module and the second controller; and the second printer controller outputs dot data to the second printhead module, wherein the dot data output by the second printer controller includes dot data it generates and at least some of the dot data received from the first printer controller.

Optionally the printer controller supplies dot data to at least one printhead module and at least partially compensating for errors in ink dot placement by at least one of a plurality of nozzles on the printhead module due to erroneous rotational displacement of the printhead module relative to a carrier, the printer being configured to:
access a correction factor associated with the at least one printhead module;

determine an order in which at least some of the dot data is supplied to at least one of the at least one printhead modules, the order being determined at least partly on the basis of the correction factor, thereby to at least partially compensate for the rotational displacement; and supply the dot data to the printhead module.

Optionally the printer controller supplies dot data to a printhead module having a plurality of nozzles for expelling ink, the printhead module including a plurality of thermal sensors, each of the thermal sensors being configured to respond to a temperature at or adjacent at least one of the nozzles, the printer controller being configured to modify operation of at least some of the nozzles in response to the temperature rising above a first threshold.
Optionally the printer controller controls a printhead comprising at least one monolithic printhead module, the at least one printhead module having a plurality of rows of nozzles configured to extend, in use, across at least part of a printable pagewidth of the printhead, the nozzles in each row being grouped into at least first and second fire groups, the printhead module being configured to sequentially fire, for each row, the nozzles of each fire group, such that each nozzle in the sequence from each fire group is fired simultaneously with respective corresponding nozzles in the sequence in the other fire groups, wherein the nozzles are fired row by row such that the nozzles of each row are all fired before the nozzles of each subsequent row, wherein the printer controller is configured to provide one or more control signals that control the order of firing of the nozzles.

Optionally the printer controller outputs to a printhead module:

dot data to be printed with at least two different inks; and control data for controlling printing of the dot data;

the printer controller including at least one communication output, each or the communication output being configured to output at least some of the control data and at least some of the dot data for the at least two inks.

Optionally the printer controller supplies data to a printhead module including at least one row of printhead nozzles, at least one row including at least one displaced row portion, the displacement of the row portion including a component in a direction normal to that of a pagewidth to be printed.

.10 Optionally the printer controller supplies print data to at least one printhead module capable of printing a maximum of n of channels of print data, the at least one printhead module being configurable into:

a fust mode, in which the printhead module is configured to receive data for a first number of the channels; and a second mode, in which the printhead module is configured to receive print data for a second number of the channels, wherein the first number is greater than the second number;

wherein the printer controller is selectively configurable to supply dot data for the first and second modes.
Optionally the printer controller supplies data to a printhead comprising a plurality of printhead modules, the printhead being wider than a reticle step used in forming the modules, the printhead comprising at least two types of the modules, wherein each type is determined by its geometric shape in plan.

Optionally the printer controller supplies one or more control signals to a printhead module, the printhead module including at least one row that comprises a plurality of adjacent sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, the method comprising providing, for each set of nozzles, a fire signal in accordance with the sequence: [nozzle position 1, nozzle position n, nozzle position 2, nozzle position (n-1), ... , nozzle position x], wherein nozzle position x is at or adjacent the centre of the set of nozzles.

Optionally the printer controller supplies dot data to a printhead module comprising at least first and second rows configured to print ink of a similar type or color, at least some nozzles in the first row being aligned with respective corresponding nozzles in the second row in a direction of intended media travel relative to the printhead, the printhead module being configurable such that the nozzles in the first and second pairs of rows are fired such that some dots output to print media are printed to by nozzles from the first pair of rows and at least some other dots output to print media are printed to by nozzles from the second pair of rows, the printer controller being configurable to supply dot data to the printhead module for printing.

Optionally the printer controller supplies dot data to at least one printhead module, the at least one printhead module comprising a plurality of rows, each of the rows comprising a plurality of nozzles for ejecting ink, wherein the printhead module includes at least first and second rows configured to print ink of a similar type or color, the printer controller being configured to supply the dot data to the at least one printhead module such that, in the event a nozzle in the first row is faulty, a corresponding nozzle in the second row prints an ink dot at a position on print media at or adjacent a position where the faulty nozzle would otherwise have printed it.
Optionally the printer controller receives first data and manipulating the first data to produce dot data to be printed, the print controller including at least two serial outputs for supplying the dot data to at least one printhead.

Optionally the printer controller supplies data to a printhead module including:
at least one row of print nozzles;

at least first and second shift registers for shifting in dot data supplied from a data source, wherein each shift register feeds dot data to a group of nozzles, and wherein each of the groups of the nozzles is interleaved with at least one of the other groups of the nozzles.

Optionally the printer controller supplies data to a printhead capable of printing a maximum of n of channels of print data, the printhead being configurable into:

a first mode, in which the printhead is configured to receive print data for a first number of the channels;
and a second mode, in which the printhead is configured to receive print data for a second number of the channels, wherein the first number is greater than the second number.

Optionally the printer controller supplies data to a printhead comprising a plurality of printhead modules, the printhead being wider than a reticle step used in forming the modules, the printhead comprising at least two types of the modules, wherein each type is determined by its geometric shape in plan.

Optionally the printer controller supplies data to a printhead module including at least one row that comprises a plurality of sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, such that, for each set of nozzles, a fire signal is provided in accordance with the sequence: [nozzle position 1, nozzle position n, nozzle position 2, nozzle position (n-1), ... , nozzle position x], wherein nozzle position x is at or adjacent the centre of the set of nozzles.

Optionally the printer controller supplies data to a printhead module including at least one row that comprises a plurality of adjacent sets of n adjacent nozzles, each of the nozzles being configured to expel the ink in response to a fire signal, the printhead being configured to output ink from nozzles at a first and nth position in each set of nozzles, and then each next inward pair of nozzles in each set, until:

in the event n is an even number, all of the nozzles in each set has been fired; and in the event n is an odd number, all of the nozzles but a central nozzle in each set have been fired, and then to fire the central nozzle.

Optionally the printer controller supplies data to a printhead module for receiving dot data to be printed using at least two different inks and control data for controlling printing of the dot data, the printhead module including a communication input for receiving the dot data for the at least two colors and the control data.

Optionally the printer controller supplies data to a printhead module including at least one row of printhead nozzles, at least one row including at least one displaced row portion, the displacement of the row portion including a component in a direction nonnal to that of apagewidth to be printed.

Optionally the printer controller supplies data to a printhead module having a plurality of rows of nozzles configured to extend, in use, across at least part of a printable pagewidth, the nozzles in each row being grouped into at least first and second fire groups, the printhead module being configured to sequentially fire, for each row, the nozzles of each fire group, such that each nozzle in the sequence from each fire group is fired simultaneously with respective corresponding nozzles in the sequence in the other fire groups, wherein the nozzles are fired row by row such that the nozzles of each row are all fired before the nozzles of each subsequent row.

Optionally the printer controller supplies data to a printhead module comprising at least first and second rows configured to print ink of a similar type or color, at least some nozzles in the first row being aligned with respective corresponding nozzles in the second row in a direction of intended media travel relative to the printhead, the printhead module being configurable such that the nozzles in the first and second pairs of rows are fired such that some dots output to print media are printed to by nozzles from the first pair of rows and at least some other dots output to print media are printed to by nozzles from the second pair of rows.

Optionally the printer controller supplies data to a printhead module that includes:
at least one row of print nozzles;

at least first and second shift registers for shifting in dot data supplied from a data source, wherein each shift register feeds dot data to a group of nozzles, and wherein each of the groups of the nozzles is interleaved with at least one of the other groups of the nozzles.

Optionally the printer controller supplies data to a printhead module having a plurality of nozzles for expelling ink, the printhead module including a plurality of thermal sensors, each of the thermal sensors being configured to respond to a temperature at or adjacent at least one of the nozzles, the printhead module being configured to modify operation of the nozzles in response to the temperature rising above a first threshold.

Optionally the printer controller supplies data to a printhead module comprising a plurality of rows, each of the rows comprising a plurality of nozzles for ejecting ink, wherein the printhead module includes at least first and second rows configured to print ink of a similar type or color, and being configured such that, in the event a nozzle in the first row is faulty, a corresponding nozzle in the second row prints an ink dot at a position on print media at or adjacent a position where the faulty nozzle would otherwise have printed it.

In a twenty first aspect the present invention provides a printer controller for receiving first data and manipulating the first data to produce dot data to be printed, the print controller including at least two serial outputs for supplying the dot data to at least one printhead, wherein each of the serial outputs is configured to supply dot data for at least two channels of the at least one printhead.

Optionally the at least two channels include at least two color channels.
Optionally the at least two channels include at least one fixative channel.

Optionally the at least two channels include at least one infrared ink channel.

Optionally the first data includes one or more instructions associated with production of the dot data from the first data, the print controller including processing means for producing the dot data from the first data on the basis of the one or more instructions.

Optionally the printhead is a pagewidth printhead.

Optionally the printer controller is for implementing a method of expelling ink from a printhead module including at least one row that comprises a plurality of sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, the method comprising the steps of:

(a) providing a fire signal to nozzles at a first and nth position in each set of nozzles;
(b) providing a fire signal to the next inward pair of nozzles in each set;

(c) in the event n is an even number, repeating step (b) until all of the nozzles in each set has been fired; and (d) in the event n is an odd number, repeating step (b) until all of the nozzles but a central nozzle in each set have been fired, and then firing the central nozzle.

Optionally the printer controller is manufactured in accordance with a method of manufacturing a plurality of printhead modules, at least some of which are capable of being combined in pairs to form bilithic pagewidth printheads, the method comprising the step of laying out each of the plurality of printhead modules on a wafer substrate, wherein at least one of the printhead modules is right-handed and at least another is left-handed.

Optionally the printer controller supplies data to a printhead module including:
at least one row of print nozzles;

at least two shift registers for shifting in dot data supplied from a data source to each of the at least one rows, wherein each print nozzle obtains dot data to be fired from an element of one of the shift registers.

Optionally the printer controller is installed in a printer comprising:

a printhead comprising at least a first elongate printhead module, the at least one printhead module including at least one row of print nozzles for expelling ink; and at least first and second printer controllers configured to receive print data and process the print data to output dot data to the printhead, wherein the first and second printer controllers are connected to a common input of the printhead.

Optionally the printer controller is installed in a printer comprising:

a printhead comprising first and second elongate printhead modules, the printhead modules being parallel to each other and being disposed end to end on either side of a join region;

at least first and second printer controllers configured to receive print data and process the print data to output dot data to the printhead, wherein the first printer controller outputs dot data only to the first printhead module and the second printer controller outputs dot data only to the second printhead module, wherein the printhead modules are configured such that no dot data passes between them.

Optionally the printer controller is installed in a printer comprising:

a printhead comprising first and second elongate printhead modules, the printhead modules being parallel to each other and being disposed end to end on either side of a join region, wherein the first printhead module is longer than the second printhead module;

at least first and second printer controllers configured to receive print data and process the print data to output dot data to the printhead, wherein: the first printer controller outputs dot data to both the fust printhead module and the second printhead module; and the second printer controller outputs dot data only to the second printhead module.

Optionally the printer controller is installed in a printer comprising:

a printhead comprising first and second elongate printhead modules, the printhead modules being parallel to each other and being disposed end to end on either side of a join region, wherein the first printhead module is longer than the second printhead module;

at least first and second printer controllers configured to receive print data and process the print data to output dot data for the printhead, wherein: the first printer controller outputs dot data to both the first printhead module and the second controller; and the second printer controller outputs dot data to the second printhead module, wherein the dot data output by the second printer controller includes dot data it generates and at least some of the dot data received from the first printer controller.

Optionally the printer controller supplies dot data to at least one printhead module and at least partially compensating for errors in ink dot placement by at least one of a plurality of nozzles on the printhead module due to erroneous rotational displacement of the printhead module relative to a carrier, the printer being configured to:
access a correction factor associated with the at least one printhead module;

determine an order in which at least some of the dot data is supplied to at least one of the at least one printhead modules, the order being determined at least partly on the basis of the correction factor, thereby to at least partially compensate for the rotational displacement; and supply the dot data to the printhead module.

Optionally the printer controller supplies dot data to a printhead module having a plurality of nozzles for expelling ink, the printhead module including a plurality of thermal sensors, each of the thermal sensors being configured to respond to a temperature at or adjacent at least one of the nozzles, the printer controller being configured to modify operation of at least some of the nozzles in response to the temperature rising above a first threshold.

Optionally the printer controller controls a printhead comprising at least one monolithic printhead module, the at least one printhead module having a plurality of rows of nozzles configured to extend, in use, across at least part of a printable pagewidth of the printhead, the nozzles in each row being grouped into at least first and second fire groups, the printhead module being configured to sequentially fire, for each row, the nozzles of each fire group, such that each nozzle in the sequence from each fire group is fired simultaneously with respective corresponding nozzles in the sequence in the other fire groups, wherein the nozzles are fired row by row such that the nozzles of each row are all fired before the nozzles of each subsequent row, wherein the printer controller is configured to provide one or more control signals that control the order of firing of the nozzles.

Optionally the printer controller outputs to a printhead module:
dot data to be printed with at least two different inks; and control data for controlling printing of the dot data;

the printer controller including at least one communication output, each or the communication output being configured to output at least some of the control data and at least some of the dot data for the at least two inks.

Optionally the printer controller supplies data to a printhead module including at least one row of printhead nozzles, at least one row including at least one displaced row portion, the displacement of the row portion including a component in a direction normal to that of a pagewidth to be printed.

Optionally the printer controller supplies print data to at least one printhead module capable of printing a maximum of n of channels of print data, the at least one printhead module being configurable into:

a first mode, in which the printhead module is configured to receive data for a first number of the channels; and a second mode, in which the printhead module is configured to receive print data for a second number of the channels, wherein the first number is greater than the second number;

wherein the printer controller is selectively configurable to supply dot data for the first and second modes.
Optionally the printer controller supplies data to a printhead comprising a plurality of printhead modules, the printhead being wider than a reticle step used in forming the modules, the printhead comprising at least two types of the modules, wherein each type is determined by its geometric shape in plan.

Optionally the printer controller supplies one or more control signals to a printhead module, the printhead module including at least one row that comprises a plurality of adjacent sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, the method comprising providing, for each set of nozzles, a fire signal in accordance with the sequence: [nozzle position 1, nozzle position n, nozzle position 2, nozzle position (n-1), ... , nozzle position x], wherein nozzle position x is at or adjacent the centre of the set of nozzles.

Optionally the printer controller supplies dot data to a printhead module comprising at least first and second rows configured to print ink of a similar type or color, at least some nozzles in the first row being aligned with respective corresponding nozzles in the second row in a direction of intended media travel relative to the printhead, the printhead module being configurable such that the nozzles in the first and second pairs of rows are fired such that some dots output to print media are printed to by nozzles from the first pair of rows and at least some other dots output to print media are printed to by nozzles from the second pair of rows, the printer controller being configurable to supply dot data to the printhead module for printing.

Optionally the printer controller supplies dot data to at least one printhead module, the at least one printhead module comprising a plurality of rows, each of the rows comprising a plurality of nozzles for ejecting ink, wherein the printhead module includes at least first and second rows configured to print ink of a similar type or color, the printer controller being configured to supply the dot data to the at least one printhead module such that, in the event a nozzle in the first row is faulty, a corresponding nozzle in the second row prints an ink dot at a position on print media at or adjacent a position where the faulty nozzle would otherwise have printed it.

Optionally the printer controller receives first data and manipulating the first data to produce dot data to be printed, the print controller including at least two serial outputs for supplying the dot data to at least one printhead.
Optionally the printer controller supplies data to a printhead module including:

at least one row of print nozzles;

at least first and second shift registers for shifting in dot data supplied from a data source, wherein each shift register feeds dot data to a group of nozzles, and wherein each of the groups of the nozzles is interleaved with at least one of the other groups of the nozzles.

Optionally the printer controller supplies data to a printhead capable of printing a maximum of n of channels of print data, the printhead being configurable into:

a first mode, in which the printhead is configured to receive print data for a first number of the channels;
and a second mode, in which the printhead is configured to receive print data for a second number of the channels, wherein the first number is greater than the second number.

Optionally the printer controller supplies data to a printhead comprising a plurality of printhead modules, the printhead being wider than a reticle step used in forming the modules, the printhead comprising at least two types of the modules, wherein each type is deternuned by its geometric shape in plan.

Optionally the printer controller supplies data to a printhead module including at least one row that comprises a plurality of sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, such that, for each set of nozzles, a fire signal is provided in accordance with the sequence: [nozzle position 1, nozzle position n, nozzle position 2, nozzle position (n-1), ... , nozzle position x], wherein nozzle position x is at or adjacent the centre of the set of nozzles.

Optionally the printer controller supplies data to a printhead module including at least one row that comprises a plurality of adjacent sets of n adjacent nozzles, each of the nozzles being configured to expel the ink in response to a fire signal, the printhead being configured to output ink from nozzles at a first and nth position in each set of nozzles, and then each next inward pair of nozzles in each set, until:

in the event n is an even number, all of the nozzles in each set has been fired; and in the event n is an odd number, all of the nozzles but a central nozzle in each set have been fired, and then to fire the central nozzle.

Optionally the printer controller supplies data to a printhead module for receiving dot data to be printed using at least two different inks and control data for controlling printing of the dot data, the printhead module including a communication input for receiving the dot data for the at least two colors and the control data.

Optionally the printer controller supplies data to a printhead module including at least one row of printhead nozzles, at least one row including at least one displaced row portion, the displacement of the row portion including a component in a direction normal to that of a pagewidth to be printed.

Optionally the printer controller supplies data to a printhead module having a plurality of rows of nozzles configured to extend, in use, across at least part of a printable pagewidth, the nozzles in each row being grouped into at least first and second fire groups, the printhead module being configured to sequentially fire, for each row, the nozzles of each fire group, such that each nozzle in the sequence from each fire group is fired simultaneously with respective corresponding nozzles in the sequence in the other fire groups, wherein the nozzles are fired row by row such that the nozzles of each row are all fired before the nozzles of each subsequent row.

Optionally the printer controller supplies data to a printhead module comprising at least first and second rows configured to print ink of a similar type or color, at least some nozzles in the first row being aligned with respective corresponding nozzles in the second row in a direction of intended media travel relative to the printhead, the printhead module being configurable such that the nozzles in the first and second pairs of rows are fired such that some dots output to print media are printed to by nozzles from the first pair of rows and at least some other dots output to print media are printed to by nozzles from the second pair of rows.

Optionally the printer controller supplies data to a printhead module that includes:
at least one row of print nozzles;

at least first and second shift registers for shifting in dot data supplied from a data source, wherein each shift register feeds dot data to a group of nozzles, and wherein each of the groups of the nozzles is interleaved with at least one of the other groups of the nozzles.

Optionally the printer controller supplies data to a printhead module having a plurality of nozzles for expelling ink, the printhead module including a plurality of thermal sensors, each of the thermal sensors being configured to respond to a temperature at or adjacent at least one of the nozzles, the printhead module being configured to modify operation of the nozzles in response to the temperature rising above a first threshold.

Optionally the printer controller supplies data to a printhead module comprising a plurality of rows, each of the rows comprising a plurality of nozzles for ejecting ink, wherein the printhead module includes at least first and second rows configured to print ink of a similar type or color, and being configured such that, in the event a nozzle in the first row is faulty, a corresponding nozzle in the second row prints an ink dot at a position on print media at or adjacent a position where the faulty nozzle would otherwise have printed it.
In a twenty second aspect the present invention provides a printhead module including:
at least one row of print nozzles;

at least first and second shift registers for shifting in dot data supplied from a data source, wherein each shift register feeds dot data to a group of nozzles, and wherein each of the groups of the nozzles is interleaved with at least one of the other groups of the nozzles.

Optionally there is a one to one correspondence between the nozzles and respective elements of the first and second shift registers.

Optionally each of the shift registers supplies dot data to about half of the nozzles in a row.

Optionally the printhead module includes at least one pair of rows of the nozzles, the rows in each pair being offset in a direction parallel to the rows by half the intra-row nozzle spacing.

Optionally each of the at least two shift registers supplies dot data to at least some of the nozzles in at least the pair of rows.

Optionally the printhead module includes a plurality of the rows configured to print using at least two ink channels, the nozzles for each of the ink channels being fed the dot data from at least one pair of first and second registers.

Optionally the printhead module is configured to receive dot data to which a method of at least partially compensating for errors in ink dot placement by at least one of a plurality of nozzles due to erroneous rotational displacement of a printhead module relative to a carrier has been applied, the nozzles being disposed on the printhead module, the method comprising the steps of:

(a) determining the rotational displacement;

(b) determining at least one correction factor that at least partially compensates for the ink dot displacement;
and (c) using the correction factor to alter the output of the ink dots to at least partially compensate for the rotational displacement.

Optionally the printhead module is configured to receive dot data to which a method of expelling ink has been applied, the method being applied to a printhead module including at least one row that comprises a plurality of adjacent sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, the method comprising providing, for each set of nozzles, a fire signal in accordance with the sequence: [nozzle position 1, nozzle position n, nozzle position 2, nozzle position (n-1), ... , nozzle position x], wherein nozzle position x is at or adjacent the centre of the set of nozzles.

Optionally the printhead module is configured to receive dot data to which a method of expelling ink has been applied, the method being applied to a printhead module including at least one row that comprises a plurality of sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, the method comprising the steps of:

(a) providing a fire signal to nozzles at a first and nth position in each set of nozzles;
(b) providing a fire signal to the next inward pair of nozzles in each set;

(c) in the event n is an even number, repeating step (b) until all of the nozzles in each set has been fired; and (d) in the event n is an odd number, repeating step (b) until all of the nozzles but a central nozzle in each set have been fired, and then firing the central nozzle.

Optionally the printhead module is manufactured in accordance with a method of manufacturing a plurality of printhead modules, at least some of which are capable of being combined in pairs to form bilithic pagewidth printheads, the method comprising the step of laying out each of the plurality of printhead modules on a wafer substrate, wherein at least one of the printhead modules is right-handed and at least another is left-handed.

Optionally the printhead module further including:
at least one row of print nozzles;

at least two shift registers for shifting in dot data supplied from a data source to each of the at least one rows, wherein each print nozzle obtains dot data to be fired from an element of one of the shift registers.

Optionally the printhead module is installed in a printer comprising:

a printhead comprising at least the first elongate printhead module, the at least one printhead module including at least one row of print nozzles for expelling ink; and at least first and second printer controllers configured to receive print data and process the print data to output dot data to the printhead, wherein the first and second printer controllers are connected to a common input of the printhead.

Optionally the printhead module is installed in a printer comprising:

a printhead comprising first and second elongate printhead modules, the printhead modules being parallel to each other and being disposed end to end on either side of a join region;

at least first and second printer controllers configured to receive print data and process the print data to output dot data to the printhead, wherein the fust printer controller outputs dot data only to the first printhead module and the second printer controller outputs dot data only to the second printhead module, wherein the printhead modules are configured such that no dot data passes between them.

Optionally the printhead module is installed in a printer comprising:

a printhead comprising first and second elongate printhead modules, the printhead modules being parallel to each other and being disposed end to end on either side of a join region, wherein the first printhead module is longer than the second printhead module;

at least first and second printer controllers configured to receive print data and process the print data to output dot data to the printhead, wherein: the first printer controller outputs dot data to both the first printhead module and the second printhead module; and the second printer controller outputs dot data only to the second printhead module.

Optionally the printhead module is installed in a printer comprising:

a printhead comprising first and second elongate printhead modules, the printhead modules being parallel to each other and being disposed end to end on either side of a join region, wherein the first printhead module is longer than the second printhead module;

at least first and second printer controllers configured to receive print data and process the print data to output dot data for the printhead, wherein: the first printer controller outputs dot data to both the first printhead module and the second controller; and the second ptinter controller outputs dot data to the second printhead module, wherein the dot data output by the second printer controller includes dot data it generates and at least some of the dot data received from the first printer controller.

Optionally the printhead module is in communication with a printer controller for supplying dot data to at least one printhead module and at least partially compensating for errors in ink dot placement by at least one of a plurality of nozzles on the printhead module due to erroneous rotational displacement of the printhead module relative to a carrier, the printer being configured to:

access a correction factor associated with the at least one printhead module;

determine an order in which at least some of the dot data is supplied to at least one of the at least one printhead modules, the order being determined at least partly on the basis of the correction factor, thereby to at least partially compensate for the rotational displacement; and supply the dot data to the printhead module.

Optionally the printhead module is in communication with a printer controller for supplying dot data to a printhead module having a plurality of nozzles for expelling ink, the printhead module including a plurality of thermal sensors, each of the thermal sensors being configured to respond to a temperature at or adjacent at least one of the nozzles, the printer controller being configured to modify operation of at least some of the nozzles in response to the temperature rising above a first threshold.

Optionally the printhead module is in communication with a printer controller for controlling a head comprising at least one monolithic printhead module, the at least one printhead module having a plurality of rows of nozzles configured to extend, in use, across at least part of a printable pagewidth of the printhead, the nozzles in each row being grouped into at least first and second fire groups, the printhead module being configured to sequentially fire, for each row, the nozzles of each fire group, such that each nozzle in the sequence from each fire group is fired simultaneously with respective corresponding nozzles in the sequence in the other fire groups, wherein the nozzles are fired row by row such that the nozzles of each row are all fired before the nozzles of each subsequent row, wherein the printer controller is configured to provide one or more control signals that control the order of firing of the nozzles.

Optionally the printhead module is, in communication with a printer controller for outputting to a printhead module:

dot data to be printed with at least two different inks; and control data for controlling printing of the dot data;

the printer controller including at least one communication output, each or the communication output being configured to output at least some of the control data and at least some of the dot data for the at least two inks.

Optionally the printhead module includes at least one row of printhead nozzles, at least one row including at least one displaced row portion, the displacement of the row portion including a component in a direction normal to that of a pagewidth to be printed.

Optionally the printhead module is in communication with a printer controller for supplying print data to at least one printhead module capable of printing a maximum of n of channels of print data, the at least one printhead module being configurable into:

a first mode, in which the printhead module is configured to receive data for a first number of the channels; and a second mode, in which the printhead module is configured to receive print data for a second number of the channels, wherein the first number is greater than the second number;

wherein the printer controller is selectively configurable to supply dot data for the first and second modes.
Optionally the printhead module is in communication with a printer controller for supplying data to a printhead comprising a plurality of printhead modules, the printhead being wider than a reticle step used in fonming the modules, the printhead comprising at least two types of the modules, wherein each type is determined by its geometric shape in plan.

Optionally the printhead module is used in conjunction with a printer controller for supplying one or more control signals to a printhead module, the printhead module including at least one row that comprises a plurality of sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, such that:

(a) a fire signal is provided to nozzles at a first and nth position in each set of nozzles;
(b) a fire signal is provided to the next inward pair of nozzles in each set;

(c) in the event n is an even number, step (b) is repeated until all of the nozzles in each set has been fired;
and (d) in the event n is an odd number, step (b) is repeated until all of the nozzles but a central nozzle in each set have been fired, and then the central nozzle is fired.

Optionally the printhead module is used in conjunction with a printer controller for supplying one or more control signals to a printhead module, the printhead module including at least one row that comprises a plurality of adjacent sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, the method comprising providing, for each set of nozzles, a fire signal in accordance with the sequence: [nozzle position 1, nozzle position n, nozzle position 2, nozzle position (n-1), ... , nozzle position x], wherein nozzle position x is at or adjacent the centre of the set of nozzles.

Optionally the printhead module is in communication with a printer controller for supplying dot data to a printhead module comprising at least first and second rows configured to print ink of a similar type or color, at least some nozzles in the first row being aligned with respective corresponding nozzles in the second row in a direction of intended media travel relative to the printhead, the printhead module being configurable such that the nozzles in the first and second pairs of rows are fired such that some dots output to print media are printed to by nozzles from the first pair of rows and at least some other dots output to print media are printed to by nozzles from the second pair of rows, the printer controller being configurable to supply dot data to the printhead module for printing.

Optionally the printhead module is in communication with a printer controller for supplying dot data to at least one printhead module, the at least one printhead module comprising a plurality of rows, each of the rows comprising a plurality of nozzles for ejecting ink, wherein the printhead module includes at least first and second rows configured to print ink of a similar type or color, the printer controller being configured to supply the dot data to the at least one printhead module such that, in the event a nozzle in the first row is faulty, a corresponding nozzle in the second row prints an ink dot at a position on print media at or adjacent a position where the faulty nozzle would otherwise have printed it.

Optionally the printhead module is in communication with a printer controller for receiving first data and manipulating the fust data to produce dot data to be printed, the print controller including at least two serial outputs for supplying the dot data to at least one printhead.

Optionally the printhead module further including:
at least one row of print nozzles;

at least first and second shift registers for shifting in dot data supplied from a data source, wherein each shift register feeds dot data to a group of nozzles, and wherein each of the groups of the nozzles is interleaved with at least one of the other groups of the nozzles.

Optionally the printhead module being capable of printing a maximum of n of channels of print data, the printhead being configurable into:

a first mode, in which the printhead is configured to receive print data for a first number of the channels;
and a second mode, in which the printhead is configured to receive print data for a second number of the channels, wherein the first number is greater than the second number.

Optionally a module further comprising a plurality of printhead modules including:
at least one row of print nozzles;

at least first and second shift registers for shifting in dot data supplied from a data source, wherein each shift register feeds dot data to a group of nozzles, and wherein each of the groups of the nozzles is interleaved with at least one of the other groups of the nozzles; and the printhead being wider than a reticle step used in fonning the modules, the printhead comprising at least two types of the modules, wherein each type is determined by its geometric shape in plan.

Optionally the printhead module includes at least one row that comprises a plurality of sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, such that, for each set of nozzles, a fire signal is provided in accordance with the sequence: [nozzle position 1, nozzle position n, nozzle position 2, nozzle position (n-1), ... , nozzle position x], wherein nozzle position x is at or adjacent the centre of the set of nozzles.

Optionally the printhead module further includes at least one row that comprises a plurality of adjacent sets of n adjacent nozzles, each of the nozzles being configured to expel the ink in response to a fire signal, the printhead being configured to output ink from nozzles at a first and nth position in each set of nozzles, and then each next inward pair of nozzles in each set, until:

in the event n is an even number, all of the nozzles in each set has been fired; and in the event n is an odd number, all of the nozzles but a central nozzle in each set have been fired, and then to fire the central nozzle.

Optionally a printhead module for receiving dot data to be printed using at least two different inks and control data for controlling printing of the dot data, the printhead module including a communication input for receiving the dot data for the at least two colors and the control data.

Optionally a printhead module further includes at least one row of printhead nozzles, at least one row including at least one displaced row portion, the displacement of the row portion including a component in a direction normal to that of a pagewidth to be printed.

Optionally a printhead module having a plurality of rows of nozzles configured to extend, in use, across at least part of a printable pagewidth, the nozzles in each row being grouped into at least first and second fire groups, the printhead module being configured to sequentially fire, for each row, the nozzles of each fire group, such that each nozzle in the sequence from each fire group is fired simultaneously with respective corresponding nozzles in the sequence in the other fire groups, wherein the nozzles are fired row by row such that the nozzles of each row are all fired before the nozzles of each subsequent row.

Optionally a printhead module further comprising at least first and second rows configured to print ink of a similar type or color, at least some nozzles in the first row being aligned with respective corresponding nozzles in the second row in a direction of intended media travel relative to the printhead, the printhead module being configurable such that the nozzles in the first and second pairs of rows are fired such that some dots output to print media are printed to by nozzles from the first pair of rows and at least some other dots output to print media are printed to by nozzles from the second pair of rows.

Optionally a printhead module is in communication with a printer controller for providing data to a printhead module that includes:

at least one row of print nozzles;

at least first and second shift registers for shifting in dot data supplied from a data source, wherein each shift register feeds dot data to a group of nozzles, and wherein each of the groups of the nozzles is interleaved with at least one of the other groups of the nozzles.

Optionally a printhead module having a plurality of nozzles for expelling ink, the printhead module including a plurality of thermal sensors, each of the thermal sensors being configured to respond to a temperature at or adjacent at least one of the nozzles, the printhead module being configured to modify operation of the nozzles in response to the temperature rising above a first threshold.

Optionally a printhead module further comprising a plurality of rows, each of the rows comprising a plurality of nozzles for ejecting ink, wherein the printhead module includes at least first and second rows configured to print ink of a similar type or color, and being configured such that, in the event a nozzle in the first row is faulty, a corresponding nozzle in the second row prints an ink dot at a position on print media at or adjacent a position where the faulty nozzle would otherwise have printed it.

In a twenty third aspect the present invention provides a printhead module capable of printing a maximum of n of channels of print data, the printhead module being configurable into:

a first mode, in which the printhead module is configured to receive print data for a first number of the channels; and a second mode, in which the printhead module is configured to receive print data for a second number of the channels, wherein the first number is greater than the second number.

Optionally the first number is n.
Optionally the first number is less than n.

Optionally the printhead module is configurable into at least one other mode, in which the printhead is configured to receive print data for a number of print channels other than the first and second numbers.

Optionally n is 4 and the second number is less than 4.

Optionally n is 5 and the second number is less than 5.

Optionally n is 6 and the second number is less than 6.
Optionally the second number is 3, 4 or 5.

Optionally the selected mode is selected based on the contents of a memory associated with the printhead.
Optionally the memory is a register.

Optionally the register is on an integrated circuit, and wherein the integrated circuit and the printhead are mounted to a print engine.

Optionally printhead comprising a plurality of printhead modules capable of printing a maximum of n of channels of print data, the printhead module being configurable into:

a first mode, in which the printhead module is configured to receive print data for a first number of the channels; and a second mode, in which the printhead module is configured to receive print data for a second number of the channels, wherein the first number is greater than the second number.

Optionally printhead is a pagewidth printhead.

Optionally the printhead module is configured to receive dot data to which a method of at least partially compensating for errors in ink dot placement by at least one of a plurality of nozzles due to erroneous rotational displacement of a printhead module relative to a carrier has been applied, the nozzles being disposed on the printhead module, the method comprising the steps of:

(a) detennining the rotational displacement;

(b) determining at least one correction factor that at least partially compensates for the ink dot displacement;
and (c) using the correction factor to alter the output of the ink dots to at least partially compensate for the rotational displacement.

Optionally the printhead module is configured to receive dot data to which a method of expelling ink has been applied, the method being applied to a printhead module including at least one row that comprises a plurality of adjacent sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, the method comprising providing, for each set of nozzles, a fire signal in accordance with the sequence: [nozzle position 1, nozzle position n, nozzle position 2, nozzle position (n-1), ... , nozzle position x], wherein nozzle position x is at or adjacent the centre of the set of nozzles.

Optionally the printhead module is configured to receive dot data to which a method of expelling ink has been applied, the method being applied to a printhead module including at least one row that comprises a plurality of sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, the method comprising the steps of:

(a) providing a fire signal to nozzles at a first and nth position in each set of nozzles;
(b) providing a fire signal to the next inward pair of nozzles in each set;

(c) in the event n is an even number, repeating step (b) until all of the nozzles in each set has been fired; and (d) in the event n is an odd number, repeating step (b) until all of the nozzles but a central nozzle in each set have been fired, and then firing the central nozzle.

Optionally the printhead module is manufactured in accordance with a method of manufacturing a plurality of printhead modules, at least some of which are capable of being combined in pairs to fonm bilithic pagewidth printheads, the method comprising the step of laying out each of the plurality of printhead modules on a wafer substrate, wherein at least one of the printhead modules is right-handed and at least another is left-handed.
Optionally the printhead module further including:

at least one row of print nozzles;

at least two shift registers for shifting in dot data supplied from a data source to each of the at least one rows, wherein each print nozzle obtains dot data to be fired from an element of one of the shift registers.

Optionally the printhead module is installed in a printer comprising:

a printhead comprising at least the first elongate printhead module, the at least one printhead module including at least one row of print nozzles for expelling ink; and at least first and second printer controllers configured to receive print data and process the print data to output dot data to the printhead, wherein the first and second printer controllers are connected to a common input of the printhead.

Optionally the printhead module is installed in a printer comprising:

a printhead comprising first and second elongate printhead modules, the printhead modules being parallel to each other and being disposed end to end on either side of a join region;

at least first and second printer controllers configured to receive print data and process the print data to output dot data to the printhead, wherein the fust printer controller outputs dot data only to the first printhead module and the second printer controller outputs dot data only to the second printhead module, wherein the printhead modules are configured such that no dot data passes between them.

Optionally the printhead module is installed in a printer comprising:

a printhead comprising first and second elongate printhead modules, the printhead modules being parallel to each other and being disposed end to end on either side of a join region, wherein the first printhead module is longer than the second printhead module;

at least first and second printer controllers configured to receive print data and process the print data to output dot data to the printhead, wherein: the first printer controller outputs dot data to both the first printhead module and the second printhead module; and the second printer controller outputs dot data only to the second printhead module.

Optionally the printhead module is installed in a printer comprising:

a printhead comprising first and second elongate printhead modules, the printhead modules being parallel to each other and being disposed end to end on either side of a join region, wherein the first printhead module is longer than the second printhead module;

at least first and second printer controllers configured to receive print data and process the print data to output dot data for the printhead, wherein: the first printer controller outputs dot data to both the first printhead module and the second controller; and the second printer controller outputs dot data to the second printhead module, wherein the dot data output by the second printer controller includes dot data it generates and at least some of the dot data received from the first printer controller.

Optionally the printhead module is in communication with a printer controller for supplying dot data to at least one printhead module and at least partially compensating for errors in ink dot placement by at least one of a plurality of nozzles on the printhead module due to erroneous rotational displacement of the printhead module relative to a carrier, the printer being configured to:

access a correction factor associated with the at least one printhead module;

determine an order in which at least some of the dot data is supplied to at least one of the at least one printhead modules, the order being determined at least partly on the basis of the correction factor, thereby to at least partially compensate for the rotational displacement; and supply the dot data to the printhead module.

Optionally the printhead module is in communication with a printer controller for supplying dot data to a printhead module having a plurality of nozzles for expelling ink, the printhead module including a plurality of thenmal sensors, each of the thermal sensors being configured to respond to a temperature at or adjacent at least one of the nozzles, the printer controller being configured to modify operation of at least some of the nozzles in response to the temperature rising above a first threshold.

Optionally the printhead module is in communication with a printer controller for controlling a head comprising at least one monolithic printhead module, the at least one printhead module having a plurality of rows of nozzles configured to extend, in use, across at least part of a printable pagewidth of the printhead, the nozzles in each row being grouped into at least first and second fire groups, the printhead module being configured to sequentially fire, for each row, the nozzles of each fire group, such that each nozzle in the sequence from each fire group is fired simultaneously with respective corresponding nozzles in the sequence in the other fire groups, wherein the nozzles are fired row by row such that the nozzles of each row are all fired before the nozzles of each subsequent row, wherein the printer controller is configured to provide one or more control signals that control the order of firing of the nozzles.

Optionally the printhead module is, in communication with a printer controller for outputting to a printhead module:

dot data to be printed with at least two different inks; and control data for controlling printing of the dot data;

the printer controller including at least one communication output, each or the communication output being configured to output at least some of the control data and at least some of the dot data for the at least two inks.
Optionally the printhead module includes at least one row of printhead nozzles, at least one row including at least one displaced row portion, the displacement of the row portion including a component in a direction normal to that of a pagewidth to be printed.

Optionally the printhead module is in communication with a printer controller for supplying print data to at least one printhead module capable of printing a maximum of n of channels of print data, the at least one printhead module being configurable into:

a first mode, in which the printhead module is configured to receive data for a fust number of the channels; and a second mode, in which the printhead module is configured to receive print data for a second number of the channels, wherein the first number is greater than the second number;

wherein the printer controller is selectively configurable to supply dot data for the first and second modes.

Optionally the printhead module is in communication with a printer controller for supplying data to a printhead comprising a plurality of printhead modules, the printhead being wider than a reticle step used in forming the modules, the printhead comprising at least two types of the modules, wherein each type is determined by its geometric shape in plan.

Optionally the printhead module is used in conjunction with a printer controller for supplying one or more control signals to a printhead module, the printhead module including at least one row that comprises a plurality of sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, such that:

(a) a fire signal is provided to nozzles at a first and nth position in each set of nozzles;
(b) a fire signal is provided to the next inward pair of nozzles in each set;

(c) in the event n is an even number, step (b) is repeated until all of the nozzles in each set has been fired;
and (d) in the event n is an odd number, step (b) is repeated until all of the nozzles but a central nozzle in each set have been fired, and then the central nozzle is fired.

Optionally the printhead module is used in conjunction with a printer controller for supplying one or more control signals to a printhead module, the printhead module including at least one row that comprises a plurality of adjacent sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, the method comprising providing, for each set of nozzles, a fire signal in accordance with the sequence: [nozzle position 1, nozzle position n, nozzle position 2, nozzle position (n-1), ... , nozzle position x], wherein nozzle position x is at or adjacent the centre of the set of nozzles.

Optionally the printhead module is in communication with a printer controller for supplying dot data to a printhead module comprising at least first and second rows configured to print ink of a similar type or color, at least some nozzles in the first row being aligned with respective corresponding nozzles in the second row in a direction of intended media travel relative to the printhead, the printhead module being configurable such that the nozzles in the first and second pairs of rows are fired such that some dots output to print media are printed to by nozzles from the first pair of rows and at least some other dots output to print media are printed to by nozzles from the second pair of rows, the piinter controller being configurable to supply dot data to the printhead module for printing.

Optionally the printhead module is in communication with a printer controller for supplying dot data to at least one printhead module, the at least one printhead module comprising a plurality of rows, each of the rows comprising a plurality of nozzles for ejecting ink, wherein the printhead module includes at least first and second rows configured to print ink of a similar type or color, the printer controller being configured to supply the dot data to the at least one printhead module such that, in the event a nozzle in the first row is faulty, a corresponding nozzle in the second row prints an ink dot at a position on print media at or adjacent a position where the faulty nozzle would otherwise have printed it.

Optionally the printhead module is in communication with a printer controller for receiving first data and manipulating the first data to produce dot data to be printed, the print controller including at least two serial outputs for supplying the dot data to at least one printhead.

Optionally the printhead module further including:

at least one row of print nozzles;

at least first and second shift registers for shifting in dot data supplied from a data source, wherein each shift register feeds dot data to a group of nozzles, and wherein each of the groups of the nozzles is interleaved with at least one of the other groups of the nozzles.

Optionally the printhead module being capable of printing a maximum of n of channels of print data, the printhead being configurable into:

a first mode, in which the printhead is configured to receive print data for a first number of the channels;
and a second mode, in which the printhead is configured to receive print data for a second number of the channels, wherein the first number is greater than the second number.

Optionally a module further comprising a plurality of printhead modules including:
at least one row of print nozzles;

at least first and second shift registers for shifting in dot data supplied from a data source, wherein each shift register feeds dot data to a group of nozzles, and wherein each of the groups of the nozzles is interleaved with at least one of the other groups of the nozzles; and the printhead being wider than a reticle step used in forming the modules, the printhead comprising at least two types of the modules, wherein each type is determined by its geometric shape in plan.

Optionally the printhead module includes at least one row that comprises a plurality of sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, such that, for each set of nozzles, a fire signal is provided in accordance with the sequence: [nozzle position 1, nozzle position n, nozzle position 2, nozzle position (n-1), ... , nozzle position x], wherein nozzle position x is at or adjacent the centre of the set of nozzles.

Optionally the printhead module further includes at least one row that comprises a plurality of adjacent sets of n adjacent nozzles, each of the nozzles being configured to expel the ink in response to a fire signal, the printhead being configured to output ink from nozzles at a first and nth position in each set of nozzles, and then each next inward pair of nozzles in each set, until:

in the event n is an even number, all of the nozzles in each set has been fired; and in the event n is an odd number, all of the nozzles but a central nozzle in each set have been fired, and then to fire the central nozzle.

Optionally a printhead module for receiving dot data to be printed using at least two different inks and control data for controlling printing of the dot data, the printhead module including a communication input for receiving the dot data for the at least two colors and the control data.

Optionally a printhead module further includes at least one row of printhead nozzles, at least one row including at least one displaced row portion, the displacement of the row portion including a component in a direction normal to that of a pagewidth to be printed.

Optionally a printhead module having a plurality of rows of nozzles configured to extend, in use, across at least part of a printable pagewidth, the nozzles in each row being grouped into at least first and second fire groups, the printhead module being configured to sequentially fire, for each row, the nozzles of each fire group, such that each nozzle in the sequence from each fire group is fired simultaneously with respective corresponding nozzles in the sequence in the other fire groups, wherein the nozzles are fired row by row such that the nozzles of each row are all fired before the nozzles of each subsequent row.

Optionally a printhead module further comprising at least first and second rows configured to print ink of a similar type or color, at least some nozzles in the first row being aligned with respective corresponding nozzles in the second row in a direction of intended media travel relative to the printhead, the printhead module being configurable such that the nozzles in the first and second pairs of rows are fired such that some dots output to print media are printed to by nozzles from the first pair of rows and at least some other dots output to print media are printed to by nozzles from the second pair of rows.

Optionally a printhead module is in communication with a printer controller for providing data to a printhead module that includes:

at least one row of print nozzles;

at least first and second shift registers for shifting in dot data supplied from a data source, wherein each shift register feeds dot data to a group of nozzles, and wherein each of the groups of the nozzles is interleaved with at least one of the other groups of the nozzles.

Optionally a printhead module having a plurality of nozzles for expelling ink, the printhead module including a plurality of thermal sensors, each of the thermal sensors being configured to respond to a temperature at or adjacent at least one of the nozzles, the printhead module being configured to modify operation of the nozzles in response to the temperature rising above a first threshold.

Optionally a printhead module further comprising a plurality of rows, each of the rows comprising a plurality of nozzles for ejecting ink, wherein the printhead module includes at least first and second rows configured to print ink of a similar type or color, and being configured such that, in the event a nozzle in the first row is faulty, a corresponding nozzle in the second row prints an ink dot at a position on print media at or adjacent a position where the faulty nozzle would otherwise have printed it.

In a twenty fourth aspect the present invention provides a printhead comprising a plurality of printhead modules, the printhead being wider than a reticle step used in forming the modules, the printhead comprising at least two types of the modules, wherein each type is determined by its geometric shape in plan.

Optionally the printhead comprising a plurality of at least one of the types of module.
Optionally the printhead comprising a plurality of each of at least two of the types of module.

Optionally the printhead comprising two types of the module.

Optionally the two types of module alternate across a print width of the printhead.

Optionally each of the modules including at least one row of print nozzles, wherein each of the at least one row of print nozzles includes at least a portion that extends at an acute angle to an intended relative direction of movement between the printhead and print media.

Optionally the different types of modules are configured, and arranged relative to each other, such that there is substantially no growth in offset of each of the at least one row of print nozzles in a direction across an intended print width of the printhead.

Optionally each of the printhead modules is a monolithic integrated circuit.

Optionally each of the modules including at least one row of print nozzles, wherein each of the at least one rows includes at least two sub-rows, each of the sub-rows being parallel to each other and displaced relative to each other in a direction of intended movement of print media relative to the printhead.

Optionally the printhead being a pagewidth printhead.
Optionally the printhead being a pagewidth printhead.
Optionally the printhead being a pagewidth printhead.

Optionally the printhead is configured to receive dot data to which a method of at least partially compensating for errors in ink dot placement by at least one of a plurality of nozzles due to erroneous rotational displacement of a printhead module relative to a carrier has been applied, the nozzles being disposed on the printhead module, the method comprising the steps of:

(a) determining the rotational displacement;

(b) determining at least one correcrion factor that at least partially compensates for the ink dot displacement;
and (c) using the correction factor to alter the output of the ink dots to at least partially compensate for the rotational displacement.

Optionally the printhead is configured to receive dot data to which a method of expelling ink has been applied, the method being applied to a printhead module including at least one row that comprises a plurality of adjacent sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, the method comprising providing, for each set of nozzles, a fire signal in accordance with the sequence: [nozzle position 1, nozzle position n, nozzle position 2, nozzle position (n-1), ... , nozzle position x], wherein nozzle position x is at or adjacent the centre of the set of nozzles.

Optionally the printhead is configured to receive dot data to which a method of expelling ink has been applied, the method being applied to a printhead module including at least one row that comprises a plurality of sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, the method comprising the steps of:

(a) providing a fire signal to nozzles at a first and nth position in each set of nozzles;
(b) providing a fire signal to the next inward pair of nozzles in each set;

(c) in the event n is an even number, repeating step (b) until all of the nozzles in each set has been fired; and (d) in the event n is an odd number, repeating step (b) until all of the nozzles but a central nozzle in each set have been fired, and then firing the central nozzle.

Optionally the printhead is manufactured in accordance with a method of manufacturing a plurality of printhead modules, at least some of which are capable of being combined in pairs to form bilithic pagewidth printheads, the method comprising the step of laying out each of the plurality of printhead modules on a wafer substrate, wherein at least one of the printhead modules is right-handed and at least another is left-handed.

Optionally the printhead further including:
at least one row of print nozzles;

at least two shift registers for shifting in dot data supplied from a data source to each of the at least one rows, wherein each print nozzle obtains dot data to be fired from an element of one of the shift registers.
Optionally the printhead is installed in a printer comprising:

a printhead comprising at least the first elongate printhead module, the at least one printhead module including at least one row of print nozzles for expelling ink; and at least first and second printer controllers configured to receive print data and process the print data to output dot data to the printhead, wherein the first and second printer controllers are connected to a common input of the printhead.

Optionally the printhead is installed in a printer comprising:

a printhead comprising first and second elongate printhead modules, the printhead modules being parallel to each other and being disposed end to end on either side of a join region;

at least first and second printer controllers configured to receive print data and process the print data to output dot data to the printhead, wherein the first printer controller outputs dot data only to the first printhead module and the second printer controller outputs dot data only to the second printhead module, wherein the printhead modules are configured such that no dot data passes between them.
Optionally the printhead is installed in a printer comprising:

a printhead comprising first and second elongate printhead modules, the printhead modules being parallel to each other and being disposed end to end on either side of a.join region, wherein the first printhead module is longer than the second printhead module;

at least first and second printer controllers configured to receive print data and process the print data to output dot data to the printhead, wherein: the first printer controller outputs dot data to both the fust printhead module and the second printhead module; and the second printer controller outputs dot data only to the second printhead module.

Optionally the printhead is installed in a printer comprising:

a printhead comprising first and second elongate printhead modules, the printhead modules being parallel to each other and being disposed end to end on either side of a join region, wherein the first printhead module is longer than the second printhead module;

at least first and second printer controllers configured to receive print data and process the print data to output dot data for the printhead, wherein: the first printer controller outputs dot data to both the first printhead module and the second controller; and the second printer controller outputs dot data to the second printhead module, wherein the dot data output by the second printer controller includes dot data it generates and at least some of the dot data received from the first printer controller.

Optionally the printhead is in communication with a printer controller for supplying dot data to at least one printhead module and at least partially compensating for errors in ink dot placement by at least one of a plurality of nozzles on the printhead module due to erroneous rotational displacement of the printhead module relative to a carrier, the printer being configured to:

access a correction factor associated with the at least one printhead module;

determine an order in which at least some of the dot data is supplied to at least one of the at least one printhead modules, the order being determined at least partly on the basis of the correction factor, thereby to at least partially compensate for the rotational displacement; and supply the dot data to the printhead module.

Optionally the printhead is in communication with a printer controller for supplying dot data to a printhead module having a plurality of nozzles for expelling ink, the printhead module including a plurality of thermal sensors, each of the thermal sensors being configured to respond to a temperature at or adjacent at least one of the nozzles, the printer controller being configured to modify operation of at least some of the nozzles in response to the temperature rising above a first threshold.

Optionally the printhead is in communication with a printer controller for controlling a head comprising at least one monolithic printhead module, the at least one printhead module having a plurality of rows of nozzles configured to extend, in use, across at least part of a printable pagewidth of the printhead, the nozzles in each row being grouped into at least first and second fire groups, the printhead module being configured to sequentially fire, for each row, the nozzles of each fire group, such that each nozzle in the sequence from each fire group is fired simultaneously with respective corresponding nozzles in the sequence in the other fire groups, wherein the nozzles are fired row by row such that the nozzles of each row are all fired before the nozzles of each subsequent row, wherein the printer controller is configured to provide one or more control signals that control the order of firing of the nozzles.

Optionally the printhead is in communication with a printer controller for outputting to a printhead module:
dot data to be printed with at least two different inks; and control data for controlling printing of the dot data;

the printer controller including at least one communication output, each or the communication output being configured to output at least some of the control data and at least some of the dot data for the at least two inks.

Optionally the printhead further including at least one row of printhead nozzles, at least one row including at least one displaced row portion, the displacement of the row portion including a component in a direction normal to that of a pagewidth to be printed.

Optionally the printhead is in communication with a printer controller for supplying print data to at least one printhead module capable of printing a maximum of n of channels of print data, the at least one printhead module being configurable into:

a first mode, in which the printhead module is configured to receive data for a first number of the channels; and a second mode, in which the printhead module is configured to receive print data for a second number of the channels, wherein the first number is greater than the second number;

wherein the printer controller is selectively configurable to supply dot data for the first and second modes.
Optionally the printhead is in communication with a printer controller for supplying data to a printhead comprising a plurality of printhead modules, the printhead being wider than a reticle step used in forming the modules, the printhead comprising at least two types of the modules, wherein each type is determined by its geometric shape in plan.

Optionally the printhead is used in conjunction with a printer controller for supplying one or more control signals to a printhead module, the printhead module including at least one row that comprises a plurality of sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, such that:

(a) a fire signal is provided to nozzles at a first and nth position in each set of nozzles;
(b) a fire signal is provided to the next inward pair of nozzles in each set;

(c) in the event n is an even number, step (b) is repeated until all of the nozzles in each set has been fired;
and (d) in the event n is an odd number, step (b) is repeated until all of the nozzles but a central nozzle in each set have been fired, and then the central nozzle is fired.

Optionally the printhead is used in conjunction with a printer controller for supplying one or more control signals to a printhead module, the printhead module including at least one row that comprises a plurality of adjacent sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, the method comprising providing, for each set of nozzles, a fire signal in accordance with the sequence: [nozzle position 1, nozzle position n, nozzle position 2, nozzle position (n-1), ... , nozzle position x], wherein nozzle position x is at or adjacent the centre of the set of nozzles.

Optionally the printhead is in communication with a printer controller for supplying dot data to a printhead module comprising at least first and second rows configured to print ink of a similar type or color, at least some nozzles in the first row being aligned with respective corresponding nozzles in the second row in a direction of intended media travel relative to the printhead, the printhead module being configurable such that the nozzles in the first and second pairs of rows are fired such that some dots output to print media are printed to by nozzles from the first pair of rows and at least some other dots output to print media are printed to by nozzles from the second pair of rows, the printer controller being configurable to supply dot data to the printhead module for printing.

Optionally the printhead is in communication with a printer controller for supplying dot data to at least one printhead module, the at least one printhead module comprising a plurality of rows, each of the rows comprising a plurality of nozzles for ejecting ink, wherein the printhead module includes at least first and second rows configured to print ink of a similar type or color, the printer controller being configured to supply the dot data to the at least one printhead module such that, in the event a nozzle in the first row is faulty, a corresponding nozzle in the second row prints an ink dot at a position on print media at or adjacent a position where the faulty nozzle would otherwise have printed it.

Optionally the printhead is in communication with a printer controller for receiving first data and manipulating the first data to produce dot data to be printed, the print controller including at least two serial outputs for supplying the dot data to at least one printhead.

Optionally the printhead further including:
at least one row of print nozzles;

at least first and second shift registers for shifting in dot data supplied from a data source, wherein each shift register feeds dot data to a group of nozzles, and wherein each of the groups of the nozzles is interleaved with at least one of the other groups of the nozzles.

Optionally the printhead being capable of printing a maximum of n of channels of print data, the printhead being configurable into:

a first mode, in which the printhead is configured to receive print data for a first number of the channels;
and a second mode, in which the printhead is configured to receive print data for a second number of the channels, wherein the first number is greater than the second number.

Optionally the printhead further including at least one row that comprises a plurality of sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, such that, for each set of nozzles, a fire signal is provided in accordance with the sequence: [nozzle position 1, nozzle position n, nozzle position 2, nozzle position (n-1), ... , nozzle position x], wherein nozzle position x is at or adjacent the centre of the set of nozzles.

Optionally the printhead further including at least one row that comprises a plurality of adjacent sets of n adjacent nozzles, each of the nozzles being configured to expel the ink in response to a fire signal, the printhead being configured to output ink from nozzles at a first and nth position in each set of nozzles, and then each next inward pair of nozzles in each set, until:

in the event n is an even number, all of the nozzles in each set has been fired; and in the event n is an odd number, all of the nozzles but a central nozzle in each set have been fired, and then to fire the central nozzle.

Optionally the printhead receives dot data to be printed using at least two different inks and control data for controlling printing of the dot data, the printhead module including a communication input for receiving the dot data for the at least two colors and the control data.

Optionally the printhead further including at least one row of printhead nozzles, at least one row including at least one displaced row portion, the displacement of the row portion including a component in a direction normal to that of a pagewidth to be printed.

Optionally the printhead having a plurality of rows of nozzles configured to extend, in use, across at least part of a printable pagewidth, the nozzles in each row being grouped into at least first and second fire groups, the printhead being configured to sequentially fire, for each row, the nozzles of each fire group, such that each nozzle in the sequence from each fire group is fired simultaneously with respective corresponding nozzles in the sequence in the other fire groups, wherein the nozzles are fired row by row such that the nozzles of each row are all fired before the nozzles of each subsequent row.

Optionally the printhead further comprising at least first and second rows configured to print ink of a similar type or color, at least some nozzles in the first row being aligned with respective corresponding nozzles in the second row in a direction of intended media travel relative to the printhead, the printhead module being configurable such that the nozzles in the first and second pairs of rows are fired such that some dots output to piint media are printed to by nozzles from the first pair of rows and at least some other dots output to print media are printed to by nozzles from the second pair of rows.

Optionally the printhead is in communication with a printer controller for providing data to a printhead module that includes:

at least one row of print nozzles;

at least first and second shift registers for shifting in dot data supplied from a data source, wherein each shift register feeds dot data to a group of nozzles, and wherein each of the groups of the nozzles is interleaved with at least one of the other groups of the nozzles.

Optionally the printhead having a plurality of nozzles for expelling ink, the printhead module including a plurality of thermal sensors, each of the thermal sensors being configured to respond to a temperature at or adjacent at least one of the nozzles, the printhead module being configured to modify operation of the nozzles in response to the temperature rising above a first threshold.

Optionally the printhead further comprising a plurality of rows, each of the rows comprising a plurality of nozzles for ejecting ink, wherein the printhead module includes at least first and second rows configured to print ink of a similar type or color, and being configured such that, in the event a nozzle in the first row is faulty, a corresponding nozzle in the second row prints an ink dot at a position on print media at or adjacent a position where the faulty nozzle would otherwise have printed it.

In a twenty fifth aspect the present invention provides a printhead module including at least one row that comprises a plurality of sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, such that, for each set of nozzles, a fire signal is provided in accordance with the sequence: [nozzle position 1, nozzle position n, nozzle position 2, nozzle position (n-1), ... , nozzle position x], wherein nozzle position x is at or adjacent the centre of the set of nozzles.

Optionally the nozzle at each given position within the set is fired simultaneously with the nozzles in the other sets at respective corresponding positions.

Optionally the printhead module includes a plurality of the rows of nozzles, the printhead module being configured to fire all the nozzles on each row prior to firing any nozzles from a subsequent row.

Optionally the rows are disposed in pairs.

Optionally the rows in each pair of rows are offset relative to each other.
Optionally each pair of rows is configured to print the same color ink.

Optionally each pair of rows is connected to a common ink source.
Optionally the sets of nozzles are adjacent each other.

Optionally the sets of nozzles are separated by an intermediate nozzle, the intermediate nozzle being fired either prior to the nozzle at position 1 in each set, or following the nozzle at position n.

Optionally a printhead comprising a plurality of printhead modules including at least one row that comprises a plurality of sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, such that, for each set of nozzles, a fire signal is provided in accordance with the sequence: [nozzle position 1, nozzle position n, nozzle position 2, nozzle position (n-1), ... , nozzle position x], wherein nozzle position x is at or adjacent the centre of the set of nozzles.

Optionally the printhead is a pagewidth printhead.

Optionally the printhead module is configured to receive dot data to which a method of at least partially compensating for errors in ink dot placement by at least one of a plurality of nozzles due to erroneous rotational displacement of a printhead module relative to a carrier has been applied, the nozzles being disposed on the printhead module, the method comprising the steps of:

(a) determining the rotational displacement;

(b) determining at least one correction factor that at least partially compensates for the ink dot displacement;
and (c) using the correction factor to alter the output of the ink dots to at least partially compensate for the rotational displacement.

Optionally the printhead module is configured to receive dot data to which a method of expelling ink has been applied, the method being applied to a printhead module including at least one row that comprises a plurality of adjacent sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, the method comprising providing, for each set of nozzles, a fire signal in accordance with the sequence: [nozzle position 1, nozzle position n, nozzle position 2, nozzle position (n-1), ... , nozzle position x], wherein nozzle position x is at or adjacent the centre of the set of nozzles.

Optionally the printhead module is configured to receive dot data to which a method of expelling ink has been applied, the method being applied to a printhead module including at least one row that comprises a plurality of sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, the method comprising the steps of:

(a) providing a fire signal to nozzles at a first and nth position in each set of nozzles;
(b) providing a fire signal to the next inward pair of nozzles in each set;

(c) in the event n is an even number, repeating step (b) until all of the nozzles in each set has been fired; and (d) in the event n is an odd number, repeating step (b) until all of the nozzles but a central nozzle in each set have been fired, and then firing the central nozzle.

Optionally the printhead module is manufactured in accordance with a method of manufacturing a plurality of printhead modules, at least some of which are capable of being combined in pairs to form bilithic pagewidth printheads, the method comprising the step of laying out each of the plurality of printhead modules on a wafer substrate, wherein at least one of the printhead modules is right-handed and at least another is left-handed.

Optionally the printhead module further including:

at least one row of print nozzles;

at least two shift registers for shifting in dot data supplied from a data source to each of the at least one rows, wherein each print nozzle obtains dot data to be fired from an element of one of the shift registers.

Optionally the printhead module is installed in a printer comprising:

a printhead comprising at least the first elongate printhead module, the at least one printhead module including at least one row of print nozzles for expelling ink; and at least first and second printer controllers configured to receive print data and process the print data to output dot data to the printhead, wherein the first and second printer controllers are connected to a common input of the printhead.

Optionally the printhead module is installed in a printer comprising:

a printhead comprising first and second elongate printhead modules, the printhead modules being parallel to each other and being disposed end to end on either side of a join region;

at least first and second printer controllers configured to receive print data and process the print data to output dot data to the printhead, wherein the fust printer controller outputs dot data only to the first printhead module and the second printer controller outputs dot data only to the second printhead module, wherein the printhead modules are configured such that no dot data passes between them.

Optionally the printhead module is installed in a printer comprising:

a printhead comprising first and second elongate printhead modules, the printhead modules being parallel to each other and being disposed end to end on either side of a join region, wherein the first printhead module is longer than the second printhead module;

at least first and second printer controllers configured to receive print data and process the print data to output dot data to the printhead, wherein: the first printer controller outputs dot data to both the fust printhead module and the second printhead module; and the second printer controller outputs dot data only to the second printhead module.

Optionally the printhead module is installed in a printer comprising:

a printhead comprising first and second elongate printhead modules, the printhead modules being parallel to each other and being disposed end to end on either side of a join region, wherein the first printhead module is longer than the second printhead module;

at least first and second printer controllers configured to receive print data and process the print data to output dot data for the printhead, wherein: the first printer controller outputs dot data to both the first printhead module and the second controller; and the second printer controller outputs dot data to the second printhead module, wherein the dot data output by the second printer controller includes dot data it generates and at least some of the dot data received from the first printer controller.

Optionally the printhead module is in communication with a printer controller for supplying dot data to at least one printhead module and at least partially compensating for errors in ink dot placement by at least one of a plurality of nozzles on the printhead module due to erroneous rotational displacement of the printhead module relative to a carrier, the printer being configured to:

access a correction factor associated with the at least one printhead module;

determine an order in which at least some of the dot data is supplied to at least one of the at least one printhead modules, the order being determined at least partly on the basis of the correction factor, thereby to at least partially compensate for the rotational displacement; and supply the dot data to the printhead module.

Optionally the printhead module is in communication with a printer controller for supplying dot data to a printhead module having a plurality of nozzles for expelling ink, the printhead module including a plurality of thermal sensors, each of the thermal sensors being configured to respond to a temperature at or adjacent at least one of the nozzles, the printer controller being configured to modify operation of at least some of the nozzles in response to the temperature rising above a first threshold.

Optionally the printhead module is in communication with a printer controller for controlling a head comprising at least one monolithic printhead module, the at least one printhead module having a plurality of rows of nozzles configured to extend, in use, across at least part of a printable pagewidth of the printhead, the nozzles in each row being grouped into at least first and second fire groups, the printhead module being configured to sequentially fire, for each row, the nozzles of each fire group, such that each nozzle in the sequence from each fire group is fired simultaneously with respective corresponding nozzles in the sequence in the other fire groups, wherein the nozzles are fired row by row such that the nozzles of each row are all fired before the nozzles of each subsequent row, wherein the printer controller is configured to provide one or more control signals that control the order of firing of the nozzles.

Optionally the printhead module is, in communication with a printer controller for outputting to a printhead module:

dot data to be printed with at least two different inks; and control data for controlling printing of the dot data;

the printer controller including at least one communication output, each or the communication output being configured to output at least some of the control data and at least some of the dot data for the at least two inks.

Optionally the printhead module includes at least one row of printhead nozzles, at least one row including at least one displaced row portion, the displacement of the row portion including a component in a direction normal to that of a pagewidth to be printed.

Optionally the printhead module is in communication with a printer controller for supplying print data to at least one printhead module capable of printing a maximum of n of channels of print data, the at least one printhead module being configurable into:

a first mode, in which the printhead module is configured to receive data for a first number of the channels; and .20 a second mode, in which the printhead module is configured to receive print data for a second number of the channels, wherein the first number is greater than the second number;

wherein the printer controller is selectively configurable to supply dot data for the first and second modes.
Optionally the printhead module is in communication with a printer controller for supplying data to a.printhead comprising a plurality of printhead modules, the printhead being wider than a reticle step used in forming the modules, the printhead comprising at least two types of the modules, wherein each type is determined by its geometric shape in plan.

Optionally the printhead module is used in conjunction with a printer controller for supplying one or more control signals to a printhead module, the printhead module including at least one row that comprises a plurality of sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, such that:

(a) a fire signal is provided to nozzles at a first and nth position in each set of nozzles;

(b) a fire signal is provided to the next inward pair of nozzles in each set;

(c) in the event n is an even number, step (b) is repeated until all of the nozzles in each set has been fired;
and (d) in the event n is an odd number, step (b) is repeated until all of the nozzles but a central nozzle in each set have been fired, and then the central nozzle is fired.

Optionally the printhead module is used in conjunction with a printer controller for supplying one or more control signals to a printhead module, the printhead module including at least one row that comprises a plurality of adjacent sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, the method comprising providing, for each set of nozzles, a fire signal in accordance with the sequence: [nozzle position 1, nozzle position n, nozzle position 2, nozzle position (n-1), ... , nozzle position x], wherein nozzle position x is at or adjacent the centre of the set of nozzles.

Optionally the printhead module is in communication with a printer controller for supplying dot data to a printhead module comprising at least first and second rows configured to print ink of a similar type or.color, at least some nozzles in the first row being aligned with respective corresponding nozzles in the second row in a direction of intended media travel relative to the printhead, the printhead module being configurable such that the nozzles in the fust and second pairs of rows are fired such that some dots output to print media are printed to by nozzles from the first pair of rows and at least some other dots output to print media are printed to by nozzles from the second pair of rows, the printer controller being configurable to supply dot data to the printhead module for printing.

Optionally the printhead module is in communication with a printer controller for supplying dot data to at least one printhead module, the at least one printhead module comprising a plurality of rows, each of the rows comprising a plurality of nozzles for ejecting ink, wherein the printhead module includes at least first and second rows configured to print ink of a similar type or color, the printer controller being configured to supply the dot data to the at least one printhead module such that, in the event a nozzle in the first row is faulty, a corresponding nozzle in the second row prints an ink dot at a position on print media at or adjacent a position where the faulty nozzle would otherwise have printed it.

Optionally the printhead module is in communication with a printer controller for receiving first data and manipulating the first data to produce dot data to be printed, the print controller including at least two serial outputs for supplying the dot data to at least one printhead.

Optionally the printhead module further including:
at least one row of print nozzles;

at least first and second shift registers for shifting in dot data supplied from a data source, wherein each shift register feeds dot data to a group of nozzles, and wherein each of the groups of the nozzles is interleaved with at least one of the other groups of the nozzles.

Optionally the printhead module being capable of printing a maximum of n of channels of print data, the printhead being configurable into:

a first mode, in which the printhead is configured to receive print data for a first number of the channels;
and a second mode, in which the printhead is configured to receive print data for a second number of the channels, wherein the first number is greater than the second number.

Optionally a module further comprising a plurality of printhead modules including:
at least one row of print nozzles;

at least first and second shift registers for shifting in dot data supplied from a data source, wherein each shift register feeds dot data to a group of nozzles, and wherein each of the groups of the nozzles is interleaved with at least one of the other groups of the nozzles; and the printhead being wider than a reticle step used in forming the modules, the printhead comprising at least two types of the modules, wherein each type is determined by its geometric shape in plan.

Optionally the printhead module includes at least one row that comprises a plurality of sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, such that, for each set of nozzles, a fire signal is provided in accordance with the sequence: [nozzle position 1, nozzle position n, nozzle position 2, nozzle position (n-1), ... , nozzle position x], wherein nozzle position x is at or adjacent the centre of the set of nozzles.

Optionally the printhead module further includes at least one row that comprises a plurality of adjacent sets of n adjacent nozzles, each of the nozzles being configured to expel the ink in response to a fire signal, the printhead being configured to output ink from nozzles at a first and nth position in each set of nozzles, and then each next inward pair of nozzles in each set, until:

in the event n is an even number, all of the nozzles in each set has been fired; and in the event n is an odd number, all of the nozzles but a central nozzle in each set have been fired, and then to fire the central nozzle.

Optionally a printhead module for receiving dot data to be printed using at least two different inks and control data for controlling printing of the dot data, the printhead module including a communication input for receiving the dot data for the at least two colors and the control data.

Optionally a printhead module further includes at least one row of printhead nozzles, at least one row including at least one displaced row portion, the displacement of the row portion including a component in a direction normal to that of a pagewidth to be printed.

Optionally a printhead module having a plurality of rows of nozzles configured to extend, in use, across at least part of a printable pagewidth, the nozzles in each row being grouped into at least first and second fire groups, the printhead module being configured to sequentially fire, for each row, the nozzles of each fire group, such that each nozzle in the sequence from each fire group is fired simultaneously with respective corresponding nozzles in the sequence in the other fire groups, wherein the nozzles are fired row by row such that the nozzles of each row are all fired before the nozzles of each subsequent row.

Optionally a printhead module further comprising at least first and second rows configured to print ink of a similar type or color, at least some nozzles in the first row being aligned with respective corresponding nozzles in the second row in a direction of intended media travel relative to the printhead, the printhead module being configurable such that the nozzles in the first and second pairs of rows are fired such that some dots output to print media are printed to by nozzles from the first pair of rows and at least some other dots output to print media are printed to by nozzles from the second pair of rows.

Optionally a printhead module is in communication with a printer controller for providing data to a printhead module that includes:

at least one row of print nozzles;

at least first and second shift registers for shifting in dot data supplied from a data source, wherein each shift register feeds dot data to a group of nozzles, and wherein each of the groups of the nozzles is interleaved with at least one of the other groups of the nozzles.

Optionally a printhead module having a plurality of nozzles for expelling ink, the printhead module including a plurality of thermal sensors, each of the thermal sensors being configured to respond to a temperature at or adjacent at least one of the nozzles, the printhead module being configured to modify operation of the nozzles in response to the temperature rising above a first threshold.

Optionally a printhead module further comprising a plurality of rows, each of the rows comprising a plurality of nozzles for ejecting ink, wherein the printhead module includes at least first and second rows configured to print ink of a similar type or color, and being configured such that, in the event a nozzle in the first row is faulty, a corresponding nozzle in the second row prints an ink dot at a position on print media at or adjacent a position where the faulty nozzle would otherwise have printed it.

Optionally the printhead module further comprising a plurality of the rows, the printhead module being configured to fire each nozzle in each row simultaneously with the nozzle or nozzles at the same position in the other rows.
Optionally the printhead module further including a plurality of pairs of the rows, each pair of rows including an odd row and an even row, the odd and even rows in each pair being offset from each other in both x and y directions relative to an intended direction of print media movement relative to the printhead, the printhead module being configured to cause firing of at least a plurality of the odd rows prior to firing any of the even rows, or vice versa.

Optionally all the odd rows are fired before any of the even rows are fired, or vice versa.

Optionally all the odd rows, or the even rows, or both, are fired in a predetermined order.

Optionally the printhead module is configurable such that the predetermined order is selectable from a plurality of predetermined available orders.

Optionally the predetermined order is sequential.

Optionally the printhead module is configurable such that the predetermined order can commence at any of a plurality of the rows.

In a twenty sixth aspect the present invention provides a printhead module including at least one row that comprises a plurality of adjacent sets of n adjacent nozzles, each of the.
nozzles being configured to expel the ink in response to a fire signal, the printhead being configured to output ink from nozzles at a first and nth position in each set of nozzles, and then each next inward pair of nozzles in each set, until:

in the event n is an even number, all of the nozzles in each set has been fired; and in the event n is an odd number, all of the nozzles but a central nozzle in each set have been fired, and then to fire the central nozzle.

Optionally the printhead module includes a plurality of the rows of nozzles, the printhead module being configured to fire all the nozzles on each row prior to firing any nozzles from a subsequent row.
Optionally the rows are disposed in pairs.

Optionally the rows in each pair of rows are offset relative to each other.
Optionally each pair of rows is configured to print the same color ink.
Optionally each pair of rows is connected to a common ink source.

Optionally the sets of nozzles are adjacent each other.

Optionally the sets of nozzles are separated by an intermediate nozzle, the intermediate nozzle being fired either prior to the nozzle at position 1 in each set, or following the nozzle at position n.

Optionally the printhead module is configured to receive dot data to which a method of at least partially compensating for errors in ink dot placement by at least one of a plurality of nozzles due to erroneous rotational displacement of a printhead module relative to a carrier has been applied, the nozzles being disposed on the printhead module, the method comprising the steps of:
(a) determining the rotational displacement;

(b) determining at least one correction factor that at least partially compensates for the ink dot displacement;
and (c) using the correction factor to alter the output of the ink dots to at least partially compensate for the rotational displacement.

Optionally the printhead module is configured to receive dot data to which a method of expelling ink has been applied, the method being applied to a printhead module including at least one row that comprises a plurality of adjacent sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, the method comprising providing, for each set of nozzles, a fire signal in accordance with the sequence: [nozzle position 1, nozzle position n, nozzle position 2, nozzle position (n-1), ... , nozzle position x], wherein nozzle position x is at or adjacent the centre of the set of nozzles.

Optionally the printhead module is configured to receive dot data to which a method of expelling ink has been applied, the method being applied to a printhead module including at least one row that comprises a plurality of sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, the method comprising the steps of:

(a) providing a fire signal to nozzles at a first and nth position in each set of nozzles;
(b) providing a fire signal to the next inward pair of nozzles in each set;

(c) in the event n is an even number, repeating step (b) until all of the nozzles in each set has been fired; and (d) in the event n is an odd number, repeating step (b) until all of the nozzles but a central nozzle in each set have been fired, and then firing the central nozzle.

Optionally the printhead module is manufactured in accordance with a method of manufacturing a plurality of printhead modules, at least some of which are capable of being combined in pairs to form bilithic pagewidth printheads, the method comprising the step of laying out each of the plurality of printhead modules on a wafer substrate, wherein at least one of the printhead modules is right-handed and at least another is left-handed.
Optionally the printhead module further including:

at least one row of print nozzles;

at least two shift registers for shifting in dot data supplied from a data source to each of the at least one rows, wherein each print nozzle obtains dot data to be fired from an element of one of the shift registers.
Optionally the printhead module is installed in a printer comprising:

a printhead comprising at least the first elongate printhead module, the at least one printhead module including at least one row of print nozzles for expelling ink; and at least first and second printer controllers configured to receive print data and process the print data to output dot data to the printhead, wherein the first and second printer controllers are connected to a common input of the printhead.

Optionally the printhead module is installed in a printer comprising:

a printhead comprising first and second elongate printhead modules, the printhead modules being parallel to each other and being disposed end to end on either side of a join region;

at least first and second printer controllers configured to receive print data and process the print data to output dot data to the printhead, wherein the first printer controller outputs dot data only to the first printhead module and the second printer controller outputs dot data only to the second printhead module, wherein the printhead modules are configured such that no dot data passes between them.

Optionally the printhead module is installed in a printer comprising:

a printhead comprising first and second elongate printhead modules, the printhead modules being parallel to each other and being disposed end to end on either side of a join region, wherein the first printhead module is longer than the second printhead module;

at least first and second printer controllers configured to receive print data and process the pcint data to output dot data to the printhead, wherein: the first printer controller outputs dot data to both the first printhead module and the second printhead module; and the second printer controller outputs dot data only to the second printhead module.

Optionally the printhead module is installed in a printer comprising:

a printhead comprising first and second elongate printhead modules, the printhead modules being parallel to each other and being disposed end to end on either side of a join region, wherein the first printhead module is longer than the second printhead module;

at least first and second printer controllers configured to receive print data and process the print data to output dot data for the printhead, wherein: the first printer controller outputs dot data to both the first printhead module and the second controller; and the second printer controller outputs dot data to the second printhead module, wherein the dot data output by the second printer controller includes dot data it generates and at least some of the dot data received from the first printer controller.

Optionally the printhead module is in communication with a printer controller for supplying dot data to at least one printhead module and at least partially compensating for errors in ink dot placement by at least one of a plurality of nozzles on the printhead module due to erroneous rotational displacement of the printhead module relative to a carrier, the printer being configured to:

access a correction factor associated with the at least one printhead module;

determine an order in which at least some of the dot data is supplied to at least one of the at least one printhead modules, the order being determined at least partly on the basis of the correction factor, thereby to at least partially compensate for the rotational displacement; and supply the dot data to the printhead module.

Optionally the printhead module is in communication with a printer controller for supplying dot data to a printhead module having a plurality of nozzles for expelling ink, the printhead module including a plurality of thermal sensors, each of the thermal sensors being configured to respond to a temperature at or adjacent at least one of the nozzles, the printer controller being configured to modify operation of at least some of the nozzles in response to the temperature rising above a first threshold.

Optionally the printhead module is in communication with a printer controller for controlling a head comprising at least one monolithic printhead module, the at least one printhead module having a plurality of rows of nozzles configured to extend, in use, across at least part of a printable pagewidth of the printhead, the nozzles in each row being grouped into at least first and second fire groups, the printhead module being configured to sequentially fire, for each row, the nozzles of each fire group, such that each nozzle in the sequence from each fire group is fired simultaneously with respective corresponding nozzles in the sequence in the other fire groups, wherein the nozzles are fired row by row such that the nozzles of each row are all fired before the nozzles of each subsequent row, wherein the printer controller is configured to provide one or more control signals that control the order of firing of the nozzles.

Optionally the printhead module is, in communication with a printer controller for outputting to a printhead module:

dot data to be printed with at least two different inks; and control data for controlling printing of the dot data;

the printer controller including at least one communication output, each or the communication output being configured to output at least some of the control data and at least some of the dot data for the at least two inks.
Optionally the printhead module includes at least one row of printhead nozzles, at least one row including at least one displaced row portion, the displacement of the row portion including a component in a direction normal to that of a pagewidth to be printed.

Optionally the printhead module is in communication with a printer controller for supplying print data to at least one printhead module capable of printing a maximum of n of channels of print data, the at least one printhead module being configurable into:

a first mode, in which the printhead module is configured to receive data for a first number of the channels; and a second mode, in which the printhead module is configured to receive print data for a second number of the channels, wherein the first number is greater than the second number;

wherein the printer controller is selectively configurable to supply dot data for the first and second modes.

Optionally the printhead module is in communication with a printer controller for supplying data to a printhead comprising a plurality of printhead modules, the printhead being wider than a reticle step used in forming the modules, the printhead comprising at least two types of the modules, wherein each type is determined by its geometric shape in plan.

Optionally the printhead module is used in conjunction with a printer controller for supplying one or more control signals to a printhead module, the printhead module including at least one row that comprises a plurality of sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, such that:

(a) a fire signal is provided to nozzles at a fust and nth position in each set of nozzles;
(b) a fire signal is provided to the next inward pair of nozzles in each set;

(c) in the event n is an even number, step (b) is repeated until all of the nozzles in each set has been fired;
and (d) in the event n is an odd number, step (b) is repeated until all of the nozzles but a central nozzle in each set have been fired, and then the central nozzle is fired.

Optionally the printhead module is used in conjunction with a printer controller for supplying one or more control signals to a printhead module, the printhead module including at least one row that comprises a plurality of adjacent sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, the method comprising providing, for each set of nozzles, a fire signal in accordance with the sequence: [nozzle position 1, nozzle position n, nozzle position 2, nozzle position (n-1), ... , nozzle position x], wherein nozzle position x is at or adjacent the centre of the set of nozzles.

Optionally the printhead module is in communication with a printer controller for supplying dot data to a printhead module comprising at least first and second rows configured to print ink of a similar type or color, at least some nozzles in the first row being aligned with respective corresponding nozzles in the second row in a direction of intended media travel relative to the printhead, the printhead module being configurable such that the nozzles in the first and second pairs of rows are fired such that some dots output to print media are printed to by nozzles from the first pair of rows and at least some other dots output to print media are printed to by nozzles from the second pair of rows, the printer controller being configurable to supply dot data to the printhead module for printing.

Optionally the printhead module is in communication with a printer controller for supplying dot data to at least one printhead module, the at least one printhead module comprising a plurality of rows, each of the rows comprising a plurality of nozzles for ejecting ink, wherein the printhead module includes at least first and second rows configured to print ink of a similar type or color, the printer controller being configured to supply the dot data to the at least one printhead module such that, in the event a nozzle in the first row is faulty, a corresponding nozzle in the second row prints an ink dot at a position on print media at or adjacent a position where the faulty nozzle would otherwise have printed it.

Optionally the printhead module is in communication with a printer controller for receiving first data and manipulating the first data to produce dot data to be printed, the print controller including at least two serial outputs for supplying the dot data to at least one printhead.

Optionally the printhead module further including:
at least one row of print nozzles;

at least first and second shift registers for shifting in dot data supplied from a data source, wherein each shift register feeds dot data to a group of nozzles, and wherein each of the groups of the nozzles is interleaved with at least one of the other groups of the nozzles.

Optionally the printhead module being capable of printing a maximum of n of channels of print data, the printhead being configurable into:

a first mode, in which the printhead is configured to receive print data for a first number of the channels;
and a second mode, in which the printhead is configured to receive print data for a second number of the channels, wherein the first number is greater than the second number.

Optionally a module further comprising a plurality of printhead modules including:
at least one row of print nozzles;

at least first and second shift registers for shifting in dot data supplied from a data source, wherein each shift register feeds dot data to a group of nozzles, and wherein each of the groups of the nozzles is interleaved with at least one of the other groups of the nozzles; and the printhead being wider than a reticle step used in forming the modules, the printhead comprising at least two types of the modules, wherein each type is determined by its geometric shape in plan.

Optionally the printhead module includes at least one row that comprises a plurality of sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, such that, for each set of nozzles, a fire signal is provided in accordance with the sequence: [nozzle position 1, nozzle position n, nozzle position 2, nozzle position (n-1), ... , nozzle position x], wherein nozzle position x is at or adjacent the centre of the set of nozzles.

Optionally the printhead module further includes at least one row that comprises a plurality of adjacent sets of n adjacent nozzles, each of the nozzles being configured to expel the ink in response to a fire signal, the printhead being configured to output ink from nozzles at a first and nth position in each set of nozzles, and then each next inward pair of nozzles in each set, until:

in the event n is an even number, all of the nozzles in each set has been fired; and in the event n is an odd number, all of the nozzles but a central nozzle in each set have been fired, and then to fire the central nozzle.

Optionally a printhead module for receiving dot data to be printed using at least two different inks and control data for controlling printing of the dot data, the printhead module including a communication input for receiving the dot data for the at least two colors and the control data.

Optionally a printhead module further includes at least one row of printhead nozzles, at least one row including at least one displaced row portion, the displacement of the row portion including a component in a direction normal to that of a pagewidth to be printed.

Optionally a printhead module having a plurality of rows of nozzles configured to extend, in use, across at least part of a printable pagewidth, the nozzles in each row being grouped into at least first and second fire groups, the printhead module being configured to sequentially fire, for each row, the nozzles of each fire group, such that each nozzle in the sequence from each fire group is fired simultaneously with respective corresponding nozzles in the sequence in the other fire groups, wherein the nozzles are fired row by row such that the nozzles of each row are all fired before the nozzles of each subsequent row.

Optionally a printhead module further comprising at least first and second rows configured to print ink of a similar type or color, at least some nozzles in the first row being aligned with respective corresponding nozzles in the second row in a direction of intended media travel relative to the printhead, the printhead module being configurable such that the nozzles in the first and second pairs of rows are fired such that some dots output to print media are printed to by nozzles from the fust pair of rows and at least some other dots output to print media are printed to by nozzles from the second pair of rows.

Optionally a printhead module is in communication with a printer controller for providing data to a printhead module that includes:

at least one row of print nozzles;

at least first and second shift registers for shifting in dot data supplied from a data source, wherein each shift register feeds dot data to a group of nozzles, and wherein each of the groups of the nozzles is interleaved with at least one of the other groups of the nozzles.

Optionally a printhead module having a plurality of nozzles for expelling ink, the printhead module including a plurality of thermal sensors, each of the thermal sensors being configured to respond to a temperature at or adjacent at least one of the nozzles, the printhead module being configured to modify operation of the nozzles in response to the temperature rising above a first threshold.

Optionally a printhead module further comprising a plurality of rows, each of the rows comprising a plurality of nozzles for ejecting ink, wherein the printhead module includes at least first and second rows configured to print ink of a similar type or color, and being configured such that, in the event a nozzle in the first row is faulty, a corresponding nozzle in the second row prints an ink dot at a position on print media at or adjacent a position where the faulty nozzle would otherwise have printed it.

Optionally the printhead module further comprising a plurality of the rows, the printhead module being configured to fire each nozzle in each row simultaneously with the nozzle or nozzles at the same position in the other rows.
Optionally the printhead module further including a plurality of pairs of the rows, each pair of rows including an odd row and an even row, the odd and even rows in each pair being offset from each other in both x and y directions relative to an intended direction of print media movement relative to the printhead, the printhead module being configured to cause firing of at least a plurality of the odd rows prior to firing any of the even rows, or vice versa.

Optionally all the odd rows are fired before any of the even rows are fired, or vice versa.

Optionally all the odd rows, or the even rows, or both, are fired in a predetermined order.

Optionally the printhead module is configurable such that the predetermined order is selectable from a plurality of predetermined available orders.

Optionally the predetermined order is sequential.

Optionally the printhead module is configurable such that the predetermined order can commence at any of a plurality of the rows.

In a twenty seventh aspect the present invention provides a printhead module for receiving dot data to be printed using at least two different inks and control data for controlling printing of the dot data, the printhead module including a communication input for receiving the dot data for the at least two colors and the control data.

Optionally the communication input is configured to receive the dot data and control data serially.
Optionally the printhead module further including a plurality of the communication inputs.
Optionally the printhead module further including a plurality of the communication inputs.

Optionally a printhead comprising a plurality of printhead modules for receiving dot data to be printed using at least two different inks and control data for controlling printing of the dot data, the printhead module including a communication input for receiving the dot data for the at least two colors and the control data;

the printhead modules being disposed end to end for printing a width exceeding that of any of the individual printhead modules, the communications input of each of the printhead modules being connected to a common dot data and control data bus.

Optionally each module is configured to respond to dot data and control data on the bus only when it is intended for that module.

Optionally the printhead module is configured to receive dot data to which a method of at least partially compensating for errors in ink dot placement by at least one of a plurality of nozzles due to erroneous rotational displacement of a printhead module relative to a carrier has been applied, the nozzles being disposed on the printhead module, the method comprising the steps of:
(a) determining the rotational displacement;

(b) determining at least one correction factor that at least partially compensates for the ink dot displacement;
and (c) using the correction factor to alter the output of the ink dots to at least partially compensate for the rotational displacement.

Optionally the printhead module is configured to receive dot data to which a method of expelling ink has been applied, the method being applied to a printhead module including at least one row that comprises a plurality of adjacent sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, the method comprising providing, for each set of nozzles, a fire signal in accordance with the sequence: [nozzle position 1, nozzle position n, nozzle position 2, nozzle position (n-1), ... , nozzle position x], wherein nozzle position x is at or adjacent the centre of the set of nozzles.

Optionally the printhead module is configured to receive dot data to which a method of expelling ink has been applied, the method being applied to a printhead module including at least one row that comprises a plurality of sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, the method comprising the steps of:

(a) providing a fire signal to nozzles at a first and nth position in each set of nozzles;
(b) providing a fire signal to the next inward pair of nozzles in each set;

(c) in the event n is an even number, repeating step (b) until all of the nozzles in each set has been fired; and (d) in the event n is an odd number, repeating step (b) until all of the nozzles but a central nozzle in each set have been fired, and then firing the central nozzle.

Optionally the printhead module is manufactured in accordance with a method of manufacturing a plurality of printhead modules, at least some of which are capable of being combined in pairs to form bilithic pagewidth printheads, the method comprising the step of laying out each of the plurality of printhead modules on a wafer substrate, wherein at least one of the printhead modules is right-handed and at least another is left-handed.
Optionally the printhead module further including:

at least one row of print nozzles;

at least two shift registers for shifting in dot data supplied from a data source to each of the at least one rows, wherein each print nozzle obtains dot data to be fired from an element of one of the shift registers.
Optionally the printhead module is installed in a printer comprising:

a printhead comprising at least the first elongate printhead module, the at least one printhead module including at least one row of print nozzles for expelling ink; and at least first and second printer controllers configured to receive print data and process the print data to output dot data to the printhead, wherein the fust and second printer controllers are connected to a common input of the printhead.

Optionally the printhead module is installed in a printer comprising:

a printhead comprising first and second elongate printhead modules, the printhead modules being parallel to each other and being disposed end to end on either side of a join region;

at least first and second printer controllers configured to receive print data and process the print data to output dot data to the printhead, wherein the first printer controller outputs dot data only to the first printhead module and the second printer controller outputs dot data only to the second printhead module, wherein the printhead modules are configured such that no dot data passes between them.

Optionally the printhead module is installed in a printer comprising:

a printhead comprising first and second elongate printhead modules, the printhead modules being parallel to each other and being disposed end to end on either side of a join region, wherein the first printhead module is longer than the second printhead module;

at least first and second printer controllers configured to receive print data and process the print data to output dot data to the printhead, wherein: the first printer controller outputs dot data to both the first printhead module and the second printhead module; and the second printer controller outputs dot data only to the second printhead module.

Optionally the printhead module is installed in a printer comprising:

a printhead comprising first and second elongate printhead modules, the printhead modules being parallel to each other and being disposed end to end on either side of a join region, wherein the first printhead module is longer than the second printhead module;

at least first and second printer controllers configured to receive print data and process the print data to output dot data for the printhead, wherein: the first printer controller outputs dot data to both the first printhead module and the second controller; and the second printer controller outputs dot data to the second printhead module, wherein the dot data output by the second printer controller includes dot data it generates and at least some of the dot data received from the first printer controller.

Optionally the printhead module is in communication with a printer controller for supplying dot data to at least one printhead module and at least partially compensating for errors in ink dot placement by at least one of a plurality of nozzles on the printhead module due to erroneous rotational displacement of the printhead module relative to a carrier, the printer being configured to:

access a correction factor associated with the at least one printhead module;

determine an order in which at least some of the dot data is supplied to at least one of the at least one printhead modules, the order being detenmined at least partly on the basis of the correction factor, thereby to at least partially compensate for the rotational displacement; and supply the dot data to the printhead module.

Optionally the printhead module is in communication with a printer controller for supplying dot data to a printhead module having a plurality of nozzles for expelling ink, the printhead module including a plurality of thermal sensors, each of the thennal sensors being configured to respond to a temperature at or adjacent at least one of the nozzles, the printer controller being configured to modify operation of at least some of the nozzles in response to the temperature rising above a first threshold.

Optionally the printhead module is in communication with a printer controller for controlling a head comprising at least one monolithic printhead module, the at least one printhead module having a plurality of rows of nozzles configured to extend, in use, across at least part of a printable pagewidth of the printhead, the nozzles in each row being grouped into at least first and second fire groups, the printhead module being configured to sequentially fire, for each row, the nozzles of each fire group, such that each nozzle in the sequence from each fire group is fired simultaneously with respective corresponding nozzles in the sequence in the other fire groups, wherein the nozzles are fired row by row such that the nozzles of each row are all fired before the nozzles of each subsequent row, wherein the printer controller is configured to provide one or more control signals that control the order of firing of the nozzles.

Optionally the printhead module is, in communication with a printer controller for outputting to a printhead module:

dot data to be printed with at least two different inks; and control data for controlling printing of the dot data;

the printer controller including at least one communication output, each or the communication output being configured to output at least some of the control data and at least some of the dot data for the at least two inks.
Optionally the printhead module includes at least one row of printhead nozzles, at least one row including at least one displaced row portion, the displacement of the row portion including a component in a direction normal to that of a pagewidth to be printed.

Optionally the printhead module is in communication with a printer controller for supplying print data to at least one printhead module capable of printing a maximum of n of channels of print data, the at least one printhead module being configurable into:

a first mode, in which the printhead module is configured to receive data for a first number of the channels; and a second mode, in which the printhead module is configured to receive print data for a second number of the channels, wherein the first number is greater than the second number;

wherein the printer controller is selectively configurable to supply dot data for the first and second modes.

Optionally the printhead module is in communication with a printer controller for supplying data to a printhead comprising a plurality of printhead modules, the printhead being wider than a reticle step used in forming the modules, the printhead comprising at least two types of the modules, wherein each type is determined by its geometric shape in plan.

Optionally the printhead module is used in conjunction with a printer controller for supplying one or more control signals to a printhead module, the printhead module including at least one row that comprises a plurality of sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, such that:

(a) a fire signal is provided to nozzles at a first and nth position in each set of nozzles;
(b) a fire signal is provided to the next inward pair of nozzles in each set;

(c) in the event n is an even number, step (b) is repeated until all of the nozzles in each set has been fired;
and (d) in the event n is an odd number, step (b) is repeated until all of the nozzles but a central nozzle in each set have been fired, and then the central nozzle is fired.

Optionally the printhead module is used in conjunction with a printer controller for supplying one or more control signals to a printhead module, the printhead module including at least one row that comprises a plurality of adjacent sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, the method comprising providing, for each set of nozzles, a fire signal in accordance with the sequence: [nozzle position 1, nozzle position n, nozzle position 2, nozzle position (n-1), ... , nozzle position x], wherein nozzle position x is at or adjacent the centre of the set of nozzles.

Optionally the printhead module is in communication with a printer controller for supplying dot data to a printhead module comprising at least first and second rows configured to print ink of a similar type or color, at least some nozzles in the first row being aligned with respective corresponding nozzles in the second row in a direction of intended media travel relative to the printhead, the printhead module being configurable such that the nozzles in the first and second pairs of rows are fired such that some dots output to print media are printed to by nozzles from the first pair of rows and at least some other dots output to print media are printed to by nozzles from the second pair of rows, the printer controller being configurable to supply dot data to the printhead module for printing.

Optionally the printhead module is in communication with a printer controller for supplying dot data to at least one printhead module, the at least one printhead module comprising a plurality of rows, each of the rows comprising a plurality of nozzles for ejecting ink, wherein the printhead module includes at least first and second rows configured to print ink of a similar type or color, the printer controller being configured to supply the dot data to the at least one printhead module such that, in the event a nozzle in the first row is faulty, a corresponding nozzle in the second row prints an ink dot at a position on print media at or adjacent a position where the faulty nozzle would otherwise have printed it.

Optionally the printhead module is in communication with a printer controller for receiving first data and manipulating the fust data to produce dot data to be printed, the print controller including at least two serial outputs for supplying the dot data to at least one printhead.

Optionally the printhead module further including:
at least one row of print nozzles;

at least first and second shift registers for shifting in dot data supplied from a data source, wherein each shift register feeds dot data to a group of nozzles, and wherein each of the groups of the nozzles is interleaved with at least one of the other groups of the nozzles.

Optionally the printhead module being capable of printing a maximum of n of channels of print data, the printhead being configurable into:

a fnst mode, in which the printhead is configured to receive print data for a first number of the channels;
and a second mode, in which the printhead is configured to receive print data for a second number of the channels, wherein the first number is greater than the second number.

Optionally a module further comprising a plurality of printhead modules including:
at least one row of print nozzles;

at least first and second shift registers for shifting in dot data supplied from a data source, wherein each shift register feeds dot data to a group of nozzles, and wherein each of the groups of the nozzles is interleaved with at least one of the other groups of the nozzles; and the printhead being wider than a reticle step used in forming the modules, the printhead comprising at least two types of the modules, wherein each type is determined by its geometric shape in plan.

Optionally the printhead module includes at least one row that comprises a plurality of sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, such that, for each set of nozzles, a fire signal is provided in accordance with the sequence: [nozzle position 1, nozzle position n, nozzle position 2, nozzle position (n-1), ... , nozzle position x], wherein nozzle position x is at or adjacent the centre of the set of nozzles.

Optionally the printhead module further includes at least one row that comprises a plurality of adjacent sets of n adjacent nozzles, each of the nozzles being configured to expel the ink in response to a fire signal, the printhead being configured to output ink from nozzles at a first and nth position in each set of nozzles, and then each next inward pair of nozzles in each set, until:

in the event n is an even number, all of the nozzles in each set has been fired; and in the event n is an odd number, all of the nozzles but a central nozzle in each set have been fired, and then to fire the central nozzle.

Optionally a printhead module for receiving dot data to be printed using at least two different inks and control data for controlling printing of the dot data, the printhead module including a communication input for receiving the dot data for the at least two colors and the control data.

Optionally a printhead module further includes at least one row of printhead nozzles, at least one row including at least one displaced row portion, the displacement of the row portion including a component in a direction normal to that of a pagewidth to be printed.

Optionally a printhead module having a plurality of rows of nozzles configured to extend, in use, across at least part of a printable pagewidth, the nozzles in each row being grouped into at least first and second fire groups, the printhead module being configured to sequentially fire, for each row, the nozzles of each fire group, such that each nozzle in the sequence from each fire group is fired simultaneously with respective corresponding nozzles in the sequence in the other fire groups, wherein the nozzles are fired row by row such that the nozzles of each row are all fired before the nozzles of each subsequent row.

Optionally a printhead module further comprising at least first and second rows configured to print ink of a similar type or color, at least some nozzles in the first row being aligned with respective corresponding nozzles in the second row in a direction of intended media travel relative to the printhead, the printhead module being configurable such that the nozzles in the first and second pairs of rows are fired such that some dots output to print media are printed to by nozzles from the first pair of rows and at least some other dots output to print media are printed to by nozzles from the second pair of rows.

Optionally a printhead module is in communication with a printer controller for providing data to a printhead module that includes:

at least one row of print nozzles;

at least first and second shift registers for shifting in dot data supplied from a data source, wherein each shift register feeds dot data to a group of nozzles, and wherein each of the groups of the nozzles is interleaved with at least one of the other groups of the nozzles.

Optionally a printhead module having a plurality of nozzles for expelling ink, the printhead module including a plurality of thermal sensors, each of the thermal sensors being configured to respond to a temperature at or adjacent at least one of the nozzles, the printhead module being configured to modify operation of the nozzles in response to the temperature rising above a first threshold.

Optionally a printhead module further comprising a plurality of rows, each of the rows comprising a plurality of nozzles for ejecting ink, wherein the printhead module includes at least first and second rows configured to piint ink of a similar type or color, and being configured such that, in the event a nozzle in the first row is faulty, a corresponding nozzle in the second row prints an ink dot at a position on print media at or adjacent a position where the faulty nozzle would otherwise have printed it.

In a twenty eighth aspect the present invention provides a printhead module including at least one row of printhead nozzles, at least one row including at least one displaced row portion, the displacement of the row portion including a component in a direction normal to that of a pagewidth to be printed.

Optionally the displaced row portion is disposed adjacent one end of the monolithic printhead module.

Optionally the printhead module further including a plurality of the rows, wherein each of at least a plurality of the rows includes one of the displaced row portions.

Optionally the displaced row portions of at least some of the rows are different in length than the displaced row portions of at least some of the other rows.

Optionally each of the rows has a displaced row portion, and the sizes of the respective displaced row portions increase from row to row in the direction nonnal to that of the pagewidth to be printed.

Optionally the dropped rows together comprise a generally trapezoidal shape, in plan.
Optionally the dropped rows together comprise a generally triangular shape, in plan.

Optionally a printhead comprising a plurality of printhead modules, including at least one of the printhead modules including at least one row of printhead nozzles, at least one row including at least one displaced row portion, the displacement of the row portion including a component in a direction normal to that of a pagewidth to be printed.

Optionally a printhead comprising a plurality of printhead modules, including at least one the printhead modules according to claim 2, wherein the displaced row portion of at least one of the printhead modules is disposed adjacent another of the printhead modules.

Optionally the printhead modules are the same shape and configuration as each other, and are arranged end to end across the intended print width.

Optionally the printhead being a pagewidth printhead.
Optionally the printhead being a pagewidth printhead.

Optionally the printhead module is configured to receive dot data to which a method of at least partially compensating for errors in ink dot placement by at least one of a plurality of nozzles due to erroneous rotational displacement of a printhead module relative to a carrier has been applied, the nozzles being disposed on the printhead module, the method comprising the steps of:

(a) determining the rotational displacement;, (b) determining at least one correction factor that at least partially compensates for the ink dot displacement;
and (c) using the correction factor to alter the output of the ink dots to at least partially compensate for the rotational displacement.

Optionally the printhead module is configured to receive dot data to which a method of expelling ink has been applied, the method being applied to a printhead module including at least one row that comprises a plurality of adjacent sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, the method comprising providing, for each set of nozzles, a fire signal in accordance with the sequence: [nozzle position 1, nozzle position n, nozzle position 2, nozzle position (n-1), ... , nozzle position x], wherein nozzle position x is at or adjacent the centre of the set of nozzles.

Optionally the printhead module is configured to receive dot data to which a method of expelling ink has been applied, the method being applied to a printhead module including at least one row that comprises a plurality of sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, the method comprising the steps of:

(a) providing a fire signal to nozzles at a first and nth position in each set of nozzles;
(b) providing a fire signal to the next inward pair of nozzles in each set;

(c) in the event n is an even number, repeating step (b) until all of the nozzles in each set has been fired; and (d) in the event n is an odd number, repeating step (b) until all of the nozzles but a central nozzle in each set have been fired, and then firing the central nozzle.

Optionally the printhead module is manufactured in accordance with a method of manufacturing a plurality of printhead modules, at least some of which are capable of being combined in pairs to form bilithic pagewidth printheads, the method comprising the step of laying out each of the plurality of printhead modules on a wafer substrate, wherein at least one of the printhead modules is right-handed and at least another is left-handed.

Optionally the printhead module further including:

at least one row of print nozzles;

at least two shift registers for shifting in dot data supplied from a data source to each of the at least one rows, wherein each print nozzle obtains dot data to be fired from an element of one of the shift registers.

Optionally the printhead module is installed in a printer comprising:

a printhead comprising at least the first elongate printhead module, the at least one printhead module including at least one row of print nozzles for expelling ink; and at least first and second printer controllers configured to receive print data and process the print data to output dot data to the printhead, wherein the fiust and second printer controllers are connected to a common input of the printhead.

Optionally the printhead module is installed in a printer comprising:

a printhead comprising first and second elongate printhead modules, the printhead modules being parallel to each other and being disposed end to end on either side of a join region;

at least first and second printer controllers configured to receive print data and process the print data to output dot data to the printhead, wherein the fust printer controller outputs dot data only to the first printhead module and the second printer controller outputs dot data only to the second printhead module, wherein the printhead modules are configured such that no dot data passes between them.

Optionally the printhead module is installed in a printer comprising:

a printhead comprising first and second elongate printhead modules, the printhead modules being parallel to each other and being disposed end to end on either side of a join region, wherein the first printhead module is longer than the second printhead module;

at least first and second printer controllers configured to receive print data and process the print data to output dot data to the printhead, wherein: the first printer controller outputs dot data to both the first printhead module and the second printhead module; and the second printer controller outputs dot data only to the second printhead module.

Optionally the printhead module is installed in a printer comprising:

a printhead comprising first and second elongate printhead modules, the printhead modules being parallel to each other and being disposed end to end on either side of a join region, wherein the first printhead module is longer than the second printhead module;

at least first and second printer controllers configured to receive print data and process the print data to output dot data for the printhead, wherein: the first printer controller outputs dot data to both the first printhead module and the second controller; and the second printer controller outputs dot data to the second printhead module, wherein the dot data output by the second printer controller includes dot data it generates and at least some of the dot data received from the first printer controller.

Optionally the printhead module is in communication with a printer controller for supplying dot data to at least one printhead module and at least parfially compensating for errors in ink dot placement by at least one of a plurality of nozzles on the printhead module due to erroneous rotational displacement of the printhead module relative to a carrier, the printer being configured to:

access a correction factor associated with the at least one printhead module;

determine an order in which at least some of the dot data is supplied to at least one of the at least one printhead modules, the order being determined at least partly on the basis of the correction factor, thereby to at least partially compensate for the rotational displacement; and supply the dot data to the printhead module.

Optionally the printhead module is in communication with a printer controller for supplying dot data to a printhead module having a plurality of nozzles for expelling ink, the printhead module including a plurality of thermal sensors, each of the thennal sensors being configured to respond to a temperature at or adjacent at least one of the nozzles, the printer controller being configured to modify operation of at least some of the nozzles in response to the temperature rising above a first threshold.

Optionally the printhead module is in communication with a printer controller for controlling a head comprising at least one monolithic printhead module, the at least one printhead module having a plurality of rows of nozzles configured to extend, in use, across at least part of a printable pagewidth of the printhead, the nozzles in each row being grouped into at least first and second fire groups, the printhead module being configured to sequentially fire, for each row, the nozzles of each fire group, such that each nozzle in the sequence from each fire group is fired simultaneously with respective corresponding nozzles in the sequence in the other fire groups, wherein the nozzles are fired row by row such that the nozzles of each row are all fired before the nozzles of each subsequent row, wherein the printer controller is configured to provide one or more control signals that control the order of firing of the nozzles.

Optionally the printhead module is, in communication with a printer controller for outputting to a printhead module:

dot data to be printed with at least two different inks; and control data for controlling printing of the dot data;

the printer controller including at least one communication output, each or the communication output being configured to output at least some of the control data and at least some of the dot data for the at least two inks.

Optionally the printhead module includes at least one row of printhead nozzles, at least one row including at least one displaced row portion, the displacement of the row portion including a component in a direction normal to that of a pagewidth to be printed.

Optionally the printhead module is in communication with a printer controller for supplying print data to at least one printhead module capable of printing a maximum of n of channels of print data, the at least one printhead module being configurable into:

a first mode, in which the printhead module is configured to receive data for a first number of the channels; and a second mode, in which the printhead module is configured to receive print data for a second number of the channels, wherein the first number is greater than the second number;

wherein the printer controller is selectively configurable to supply dot data for the first and second modes.
Optionally the printhead module is in communication with a printer controller for supplying data to a printhead comprising a plurality of printhead modules, the printhead being wider than a reticle step used in forming the modules, the printhead comprising at least two types of the modules, wherein each type is deterniined by its geometric shape in plan.

Optionally the printhead module is used in conjunction with a printer controller for supplying one or more control signals to a printhead module, the printhead module including at least one row that comprises a plurality of sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, such that:

(a) a fire signal is provided to nozzles at a first and nth position in each set of nozzles;

(b) a fire signal is provided to the next inward pair of nozzles in each set;

(c) in the event n is an even number, step (b) is repeated until all of the nozzles in each set has been fired;
and (d) in the event n is an odd number, step (b) is repeated until all of the nozzles but a central nozzle in each set have been fired, and then the central nozzle is fired.

Optionally the printhead module is used in conjunction with a printer controller for supplying one or more control signals to a printhead module, the printhead module including at least one row that comprises a plurality of adjacent sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, the method comprising providing, for each set of nozzles, a fire signal in accordance with the sequence: [nozzle position 1, nozzle position n, nozzle position 2, nozzle position (n-1), ... , nozzle position x], wherein nozzle position x is at or adjacent the centre of the set of nozzles.

Optionally the printhead module is in communication with a printer controller for supplying dot data to a printhead module comprising at least first and second rows configured to print ink of a similar type or color, at least some nozzles in the first row being aligned with respective corresponding nozzles in the second row in a direction of intended media travel relative to the printhead, the printhead module being configurable such that the nozzles in the first and second pairs of rows are fired such that some dots output to print media are printed to by nozzles from the first pair of rows and at least some other dots output to print media are printed to by nozzles from the second pair of rows, the printer controller being configurable to supply dot data to the printhead module for printing.

Optionally the printhead module is in communication with a printer controller for supplying dot data to at least one printhead module, the at least one printhead module comprising a plurality of rows, each of the rows comprising a plurality of nozzles for ejecting ink, wherein the printhead module includes at least first and second rows configured to print ink of a similar type or color, the printer controller being configured to supply the dot data to the at least one printhead module such that, in the event a nozzle in the first row is faulty, a corresponding nozzle in the second row prints an ink dot at a position on print media at or adjacent a position where the faulty nozzle would otherwise have printed it.

Optionally the printhead module is in communication with a printer controller for receiving first data and manipulating the first data to produce dot data to be printed, the print controller including at least two serial outputs for supplying the dot data to at least one printhead.

Optionally the printhead module further including:
at least one row of print nozzles;

at least first and second shift registers for shifting in dot data supplied from a data source, wherein each shift register feeds dot data to a group of nozzles, and wherein each of the groups of the nozzles is interleaved with at least one of the other groups of the nozzles.

Optionally the printhead module being capable of printing a maximum of n of channels of print data, the printhead being configurable into:

a first mode, in which the printhead is configured to receive print data for a first number of the channels;
and a second mode, in which the printhead is configured to receive print data for a second number of the channels, wherein the first number is greater than the second number.

Optionally a module further comprising a plurality of printhead modules including:
at least one row of print nozzles;

at least first and second shift registers for shifting in dot data supplied from a data source, wherein each shift register feeds dot data to a group of nozzles, and wherein each of the groups of the nozzles is interleaved with at least one of the other groups of the nozzles; and the printhead being wider than a reticle step used in forming the modules, the printhead comprising at least two types of the modules, wherein each type is determined by its geometric shape in plan.

Optionally the printhead module includes at least one row that comprises a plurality of sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, such that, for each set of nozzles, a fire signal is provided in accordance with the sequence: [nozzle position 1, nozzle position n, nozzle position 2, nozzle position (n-1), ... , nozzle position x], wherein nozzle position x is at or adjacent the centre of the set of nozzles.

Optionally the printhead module further includes at least one row that comprises a plurality of adjacent sets of n adjacent nozzles, each of the nozzles being configured to expel the ink in response to a fire signal, the printhead being configured to output ink from nozzles at a first and nth position in each set of nozzles, and then each next inward pair of nozzles in each set, until:

in the event n is an even number, all of the nozzles in each set has been fired; and in the event n is an odd number, all of the nozzles but a central nozzle in each set have been fired, and then to fire the central nozzle.

Optionally a printhead module for receiving dot data to be printed using at least two different inks and control data for controlling printing of the dot data, the printhead module including a communication input for receiving the dot data for the at least two colors and the control data.

Optionally a printhead module further includes at least one row of printhead nozzles, at least one row including at least one displaced row portion, the displacement of the row portion including a component in a direction normal to that of a pagewidth to be printed.

Optionally a printhead module having a plurality of rows of nozzles configured to extend, in use, across at least part of a printable pagewidth, the nozzles in each row being grouped into at least first and second fire groups, the printhead module being configured to sequentially fire, for each row, the nozzles of each fire group, such that each nozzle in the sequence from each fire group is fired simultaneously with respective corresponding nozzles in the sequence in the other fire groups, wherein the nozzles are fired row by row such that the nozzles of each row are all fired before the nozzles of each subsequent row.

Optionally a printhead module further comprising at least first and second rows configured to print ink of a similar type or color, at least some nozzles in the first row being aligned with respective corresponding nozzles in the second row in a direction of intended media travel relative to the printhead, the printhead module being configurable such that the nozzles in the first and second pairs of rows are fired such that some dots output to print media are printed to by nozzles from the first pair of rows and at least some other dots output to print media are printed to by nozzles from the second pair of rows.

Optionally a printhead module is in communication with a printer controller for providing data to a printhead module that includes:

at least one row of print nozzles;

at least first and second shift registers for shifting in dot data supplied from a data source, wherein each shift register feeds dot data to a group of nozzles, and wherein each of the groups of the nozzles is interleaved with at least one of the other groups of the nozzles.

Optionally a printhead module having a plurality of nozzles for expelling ink, the printhead module including a plurality of thermal sensors, each of the thermal sensors being configured to respond to a temperature at or adjacent at least one of the nozzles, the printhead module being configured to modify operation of the nozzles in response to the temperature rising above a first threshold.

Optionally a printhead module further comprising a plurality of rows, each of the rows comprising a plurality of nozzles for ejecting ink, wherein the printhead module includes at least first and second rows configured to print ink of a similar type or color, and being configured such that, in the event a nozzle in the first row is faulty, a corresponding nozzle in the second row prints an ink dot at a position on print media at or adjacent a position where the faulty nozzle would otherwise have printed it.

In a twenty ninth aspect the present invention provides a printhead module having a plurality of rows of nozzles configured to extend, in use, across at least part of a printable pagewidth, the nozzles in each row being grouped into at least first and second fire groups, the printhead module being configured to sequentially fire, for each row, the nozzles of each fire group, such that each nozzle in the sequence from each fire group is fired simultaneously with respective corresponding nozzles in the sequence in the other fire groups, wherein the nozzles are fired row by row such that the nozzles of each row are all fired before the nozzles of each subsequent row.

Optionally the rows are disposed in pairs extending generally transverse to a direction media is to be moved relative to the printhead.

Optionally the rows in each pair of rows are configured to print the same color ink as each other.
Optionally the rows in each pair of rows share an ink supply.

Optionally the rows in each pair of rows are offset with respect to each other.

Optionally the printhead module is configured to fire the nozzles such that at least some ink dots from one row land on top of dots previously deposited by one or more of the other rows.

Optionally the printhead module is operable in at least two fire modes, wherein at least some of the at least two fire modes define relatively different numbers of nozzles in each of the fire groups.

Optionally at least some of the at least two fire groups define relatively different fire group sequences.
Optionally a printhead comprising a plurality of printhead modules having a plurality of rows of nozzles configured to extend, in use, across at least part of a printable pagewidth, the nozzles in each row being grouped into at least first and second fire groups, the printhead module being configured to sequentially fire, for each row, the nozzles of each fire group, such that each nozzle in the sequence from each fire group is fired simultaneously with respective corresponding nozzles in the sequence in the other fire groups, wherein the nozzles are fired row by row such that the nozzles of each row are all fired before the nozzles of each subsequent row.

Optionally the printhead is a pagewidth printhead.

Optionally the printhead module is configured to receive dot data to which a method of at least partially compensating for errors in ink dot placement by at least one of a plurality of nozzles due to erroneous rotational displacement of a printhead module relative to a carrier has been applied, the nozzles being disposed on the printhead module, the method comprising the steps of:
(a) determining the rotational displacement;

(b) determining at least one correction factor that at least partially compensates for the ink dot displacement;
and (c) using the correction factor to alter the output of the ink dots to at least partially compensate for the rotational displacement.

Optionally the printhead module is configured to receive dot data to which a method of expelling ink has been applied, the method being applied to a printhead module including at least one row that comprises a plurality of adjacent sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, the method comprising providing, for each set of nozzles, a fire signal in accordance with the sequence: [nozzle position 1, nozzle position n, nozzle position 2, nozzle position (n-1), ... , nozzle position x], wherein nozzle position x is at or adjacent the centre of the set of nozzles.

Optionally the printhead module is configured to receive dot data to which a method of expelling ink has been applied, the method being applied to a printhead module including at least one row that comprises a plurality of sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, the method comprising the steps of (a) providing a fire signal to nozzles at a first and nth position in each set of nozzles;
(b) providing a fire signal to the next inward pair of nozzles in each set;

(c) in the event n is an even number, repeating step (b) until all of the nozzles in each set has been fired; and (d) in the event n is an odd number, repeating step (b) until all of the nozzles but a central nozzle in each set have been fired, and then firing the central nozzle.

Optionally the printhead module is manufactured in accordance with a method of manufacturing a plurality of printhead modules, at least some of which are capable of being combined in pairs to form bilithic pagewidth printheads, the method comprising the step of laying out each of the plurality of printhead modules on a wafer substrate, wherein at least one of the printhead modules is right-handed and at least another is left-handed.
Optionally the printhead module further including:

at least one row of print nozzles;

at least two shift registers for shifting in dot data supplied from a data source to each of the at least one rows, wherein each print nozzle obtains dot data to be fired from an element of one of the shift registers.
Optionally the printhead module is installed in a printer comprising:

a printhead comprising at least the first elongate printhead module, the at least one printhead module including at least one row of print nozzles for expelling ink; and at least first and second printer controllers configured to receive print data and process the print data to output dot data to the printhead, wherein the first and second printer controllers are connected to a common input of the printhead.

Optionally the printhead module is installed in a printer comprising:

a printhead comprising first and second elongate printhead modules, the printhead modules being parallel to each other and being disposed end to end on either side of a join region;

at least first and second printer controllers configured to receive print data and process the print data to output dot data to the printhead, wherein the first printer controller outputs dot data only to the first printhead module and the second printer controller outputs dot data only to the second printhead module, wherein the printhead modules are configured such that no dot data passes between them.

Optionally the printhead module is installed in a printer comprising:

a printhead comprising first and second elongate printhead modules, the printhead modules being parallel to each other and being disposed end to end on either side of a join region, wherein the first printhead module is longer than the second printhead module;

at least first and second printer controllers configured to receive print data and process the print data to output dot data to the printhead, wherein: the first printer controller outputs dot data to both the first printhead module and the second printhead module; and the second printer controller outputs dot data only to the second printhead module.

Optionally the printhead module is installed in a printer comprising:

a printhead comprising first and second elongate printhead modules, the printhead modules being parallel to each other and being disposed end to end on either side of a join region, wherein the first printhead module is longer than the second printhead module;

at least first and second printer controllers configured to receive print data and process the print data to output dot data for the printhead, wherein: the first printer controller outputs dot data to both the first printhead module and the second controller; and the second printer controller outputs dot data to the second printhead module, wherein the dot data output by the second printer controller includes dot data it generates and at least some of the dot data received from the first printer controller.

Optionally the printhead module is in communication with a printer controller for supplying dot data to at least one printhead module and at least partially compensating for errors in ink dot placement by at least one of a plurality of nozzles on the printhead module due to erroneous rotational displacement of the printhead module relative to a carrier, the printer being configured to:

access a correction factor associated with the at least one printhead module;

determine an order in which at least some of the dot data is supplied to at least one of the at least one printhead modules, the order being determined at least partly on the basis of the correction factor, thereby to at least partially compensate for the rotational displacement; and supply the dot data to the printhead module.

Optionally the printhead module is in communication with a printer controller for supplying dot data to a printhead module having a plurality of nozzles for expelling ink, the printhead module including a plurality of thermal sensors, each of the thermal sensors being configured to respond to a temperature at or adjacent at least one of the nozzles, the printer controller being configured to modify operation of at least some of the nozzles in response to the temperature rising above a first threshold.

Optionally the printhead module is in communication with a printer controller for controlling a head comprising at least one monolithic printhead module, the at least one printhead module having a plurality of rows of nozzles configured to extend, in use, across at least part of a printable pagewidth of the printhead, the nozzles in each row being grouped into at least first and second fire groups, the printhead module being configured to sequentially fire, for each row, the nozzles of each fire group, such that each nozzle in the sequence from each fire group is fired simultaneously with respective corresponding nozzles in the sequence in the other fire groups, wherein the nozzles are fired row by row such that the nozzles of each row are all fired before the nozzles of each subsequent row, wherein the printer controller is configured to provide one or more control signals that control the order of firing of the nozzles.

Optionally the printhead module is, in communication with a printer controller for outputting to a printhead module:

dot data to be printed with at least two different inks; and control data for controlling printing of the dot data;

the printer controller including at least one conununication output, each or the communication output being configured to output at least some of the control data and at least some of the dot data for the at least two inks.

Optionally the printhead module includes at least one row of printhead nozzles, at least one row including at least one displaced row portion, the displacement of the row portion including a component in a direction normal to that of a pagewidth to be printed.

Optionally the printhead module is in communication with a printer controller for supplying print data to at least one printhead module capable of printing a maximum of n of channels of print data, the at least one printhead module being configurable into:

a first mode, in which the printhead module is configured to receive data for a first number of the channels; and a second mode, in which the printhead module is configured to receive print data for a second number of the channels, wherein the first number is greater than the second number;

wherein the printer controller is selectively configurable to supply dot data for the first and second modes.

Optionally the printhead module is in communication with a printer controller for supplying data to a printhead comprising a plurality of printhead modules, the printhead being wider than a reticle step used in forming the modules, the printhead comprising at least two types of the modules, wherein each type is determined by its geometric shape in plan.

Optionally the printhead module is used in conjunction with a printer controller for supplying one or more control signals to a printhead module, the printhead module including at least one row that comprises a plurality of sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, such that:

(a) a fire signal is provided to nozzles at a first and nth position in each set of nozzles;
(b) a fire signal is provided to the next inward pair of nozzles in each set;

(c) in the event n is an even number, step (b) is repeated until all of the nozzles in each set has been fired;
and (d) in the event n is an odd number, step (b) is repeated until all of the nozzles but a central nozzle in each set have been fired, and then the central nozzle is fired.

Optionally the printhead module is used in conjunction with a printer controller for supplying one or more control signals to a printhead module, the printhead module including at least one row that comprises a plurality of adjacent sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, the method comprising providing, for each set of nozzles, a fire signal in accordance with the sequence: [nozzle position 1, nozzle position n, nozzle position 2, nozzle position (n-1), ... , nozzle position x], wherein nozzle position x is at or adjacent the centre of the set of nozzles.

Optionally the printhead module is in communication with a printer controller for supplying dot data to a printhead module comprising at least first and second rows configured to print ink of a similar type or color, at least some nozzles in the first row being aligned with respective corresponding nozzles in the second row in a direction of intended media travel relative to the printhead, the printhead module being configurable such that the nozzles in the first and second pairs of rows are fired such that some dots output to print media are printed to by nozzles from the first pair of rows and at least some other dots output to print media are printed to by nozzles from the second pair of rows, the printer controller being configurable to supply dot data to the printhead module for printing.

Optionally the printhead module is in communication with a printer controller for supplying dot data to at least one printhead module, the at least one printhead module comprising a plurality of rows, each of the rows comprising a plurality of nozzles for ejecting ink, wherein the printhead module includes at least first and second rows configured to print ink of a similar type or color, the printer controller being configured to supply the dot data to the at least one printhead module such that, in the event a nozzle in the first row is faulty, a corresponding nozzle in the second row prints an ink dot at a position on print media at or adjacent a position where the faulty nozzle would otherwise have printed it.

Optionally the printhead module is in communication with a printer controller for receiving first data and manipulating the first data to produce dot data to be printed, the print controller including at least two serial outputs for supplying the dot data to at least one printhead.

Optionally the printhead module further including:
at least one row of print nozzles;

at least first and second shift registers for shifting in dot data supplied from a data source, wherein each shift register feeds dot data to a group of nozzles, and wherein each of the groups of the nozzles is interleaved with at least one of the other groups of the nozzles.

Optionally the printhead module being capable of printing a maximum of n of channels of print data, the printhead being configurable into:

a fust mode, in which the printhead is configured to receive print data for a first number of the channels;
and a second mode, in which the printhead is configured to receive print data for a second number of the channels, wherein the first number is greater than the second number.

Optionally a module further comprising a plurality of printhead modules including:
at least one row of print nozzles;

at least first and second shift registers for shifting in dot data supplied from a data source, wherein each shift register feeds dot data to a group of nozzles, and wherein each of the groups of the nozzles is interleaved with at least one of the other groups of the nozzles; and the printhead being wider than a reticle step used in forming the modules, the printhead comprising at least two types of the modules, wherein each type is determined by its geometric shape in plan.

Optionally the printhead module includes at least one row that comprises a plurality of sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, such that, for each set of nozzles, a fire signal is provided in accordance with the sequence: [nozzle position 1, nozzle position n, nozzle position 2, nozzle position (n-1), ... , nozzle position x], wherein nozzle position x is at or adjacent the centre of the set of nozzles.

Optionally the printhead module further includes at least one row that comprises a plurality of adjacent sets of n adjacent nozzles, each of the nozzles being configured to expel the ink in response to a fire signal, the printhead being configured to output ink from nozzles at a first and nth position in each set of nozzles, and then each next inward pair of nozzles in each set, until:

in the event n is an even number, all of the nozzles in each set has been fired; and in the event n is an odd number, all of the nozzles but a central nozzle in each set have been fired, and then to fire the central nozzle.

Optionally a printhead module for receiving dot data to be printed using at least two different inks and control data for controlling printing of the dot data, the printhead module including a communication input for receiving the dot data for the at least two colors and the control data.

Optionally a printhead module further includes at least one row of printhead nozzles, at least one row including at least one displaced row portion, the displacement of the row portion including a component in a direction normal to that of a pagewidth to be printed.

Optionally a printhead module having a plurality of rows of nozzles configured to extend, in use, across at least part of a printable pagewidth, the nozzles in each row being grouped into at least first and second fire groups, the printhead module being configured to sequentially fire, for each row, the nozzles of each fire group, such that each nozzle in the sequence from each fire group is fired simultaneously with respective corresponding nozzles in the sequence in the other fire groups, wherein the nozzles are fired row by row such that the nozzles of each row are all fired before the nozzles of each subsequent row.

Optionally a printhead module further comprising at least first and second rows configured to print ink of a similar type or color, at least some nozzles in the first row being aligned with respective corresponding nozzles in the second row in a direction of intended media travel relative to the printhead, the printhead module being configurable such that the nozzles in the first and second pairs of rows are fired such that some dots output to print media are printed to by nozzles from the first pair of rows and at least some other dots output to print media are printed to by nozzles from the second pair of rows.

Optionally a printhead module is in communication with a printer controller for providing data to a printhead module that includes:

at least one row of print nozzles;

at least first and second shift registers for shifting in dot data supplied from a data source, wherein each shift register feeds dot data to a group of nozzles, and wherein each of the groups of the nozzles is interleaved with at least one of the other groups of the nozzles.

Optionally a printhead module having a plurality of nozzles for expelling ink, the printhead module including a plurality of thermal sensors, each of the thermal sensors being configured to respond to a temperature at or adjacent at least one of the nozzles, the printhead module being configured to modify operation of the nozzles in response to the temperature rising above a first threshold.

Optionally a printhead module further comprising a plurality of rows, each of the rows comprising a plurality of nozzles for ejecting ink, wherein the printhead module includes at least first and second rows configured to print ink of a similar type or color, and being configured such that, in the event a nozzle in the first row is faulty, a coTresponding nozzle in the second row prints an ink dot at a position on print media at or adjacent a position where the faulty nozzle would otherwise have printed it.

Optionally the printhead module further comprises a plurality of the rows, the printhead module being configured to fire each nozzle in each row simultaneously with the nozzle or nozzles at the same position in the other rows.

Optionally the printhead module further includes a plurality of pairs of the rows, each pair of rows including an odd row and an even row, the odd and even rows in each pair being offset from each other in both x and y directions relative to an intended direction of print media movement relative to the printhead, the printhead module being configured to cause firing of at least a plurality of the odd rows prior to firing any of the even rows, or vice versa.

Optionally all the odd rows are fired before any of the even rows are fired, or vice versa.
Optionally all the odd rows, or the even rows, or both, are fired in a predetermined order.

Optionally the printhead module is configurable such that the predetermined order is selectable from a plurality of predetermined available orders.

Optionally the predetermined order is sequential.

Optionally the printhead module is configurable such that the predetermined order can commence at any of a plurality of the rows.

In a thirtieth aspect the present invention provides a printhead module comprising at least first and second rows configured to print ink of a similar type or color, at least some nozzles in the first row being aligned with respective corresponding nozzles in the second row in a direction of intended media travel relative to the printhead, the printhead module being configurable such that the nozzles in the first and second rows are fired such that some dots output to print media are printed to by nozzles from the first row and at least some other dots output to print media are printed to by nozzles from the second row.

Optionally the printhead module is controllable such that either of the nozzles in each aligned pair of nozzles in the first and second rows can be selected to output ink for a selected dot to be printed on the print media.
Optionally in the event a nozzle in the first row is faulty, the corresponding nozzle in the second row is selected to output ink for a dot for which the faulty nozzle would otherwise have output ink.
Optionally the printhead module includes a plurality of sets of the first and second rows.

Optionally each of the sets of the first and second rows is configured to print in a single color or ink type.

Optionally the first and second rows in at least one of the sets are separated by one or more rows from the other set or sets.

Optionally each of the rows includes an odd sub-row and an even sub-row, the odd and even sub-rows being offset with respect to each other in a direction of intended print media travel relative to the printhead.
Optionally the odd and even sub-rows are transversely offset relative to each other.

Optionally the printhead module is configured such that the first and second rows are fired alternately.

Optionally a printhead comprising a plurality of printhead modules comprising at least first and second rows configured to print ink of a similar type or color, at least some nozzles in the first row being aligned with respective corresponding nozzles in the second row in a direction of intended media travel relative to the printhead, the printhead module being configurable such that the nozzles in the first and second rows are fired such that some dots output to print media are printed to by nozzles from the first row and at least some other dots output to print media are printed to by nozzles from the second row.

Optionally the printhead being a pagewidth printhead.

Optionally the printhead module is configured to receive dot data to which a method of at least partially compensating for errors in ink dot placement by at least one of a plurality of nozzles due to erroneous rotational displacement of a printhead module relative to a can-ier has been applied, the nozzles being disposed on the printhead module, the method comprising the steps of:

(a) determining the rotational displacement;

(b) determining at least one correction factor that at least partially compensates for the ink dot displacement;
and (c) using the correction factor to alter the output of the ink dots to at least partially compensate for the rotational displacement.

Optionally the printhead module is configured to receive dot data to which a method of expelling ink has been applied, the method being applied to a printhead module including at least one row that comprises a plurality of adjacent sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, the method comprising providing, for each set of nozzles, a fire signal in accordance with the sequence: [nozzle position 1, nozzle position n, nozzle position 2, nozzle position (n-1), ... , nozzle position x], wherein nozzle position x is at or adjacent the centre of the set of nozzles.

Optionally the printhead module is configured to receive dot data to which a method of expelling ink has been applied, the method being applied to a printhead module including at least one row that comprises a plurality of sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, the method comprising the steps of:

(a) providing a fire signal to nozzles at a first and nth position in each set of nozzles;
(b) providing a fire signal to the next inward pair of nozzles in each set;

(c) in the event n is an even number, repeating step (b) until all of the nozzles in each set has been fired; and (d) in the event n is an odd number, repeating step (b) until all of the nozzles but a central nozzle in each set have been fired, and then firing the central nozzle.

Optionally the printhead module is manufactured in accordance with a method of manufacturing a plurality of printhead modules, at least some of which are capable of being combined in pairs to form bilithic pagewidth printheads, the method comprising the step of laying out each of the plurality of printhead modules on a wafer substrate, wherein at least one of the printhead modules is right-handed and at least another is left-handed.
Optionally the printhead module further including:

at least one row of print nozzles;

at least two shift registers for shifting in dot data supplied from a data source to each of the at least one rows, wherein each print nozzle obtains dot data to be fired from an element of one of the shift registers.
Optionally the printhead module is installed in a printer comprising:

a printhead comprising at least the first elongate printhead module, the at least one printhead module including at least one row of print nozzles for expelling ink; and at least first and second printer controllers configured to receive print data and process the print data to output dot data to the printhead, wherein the first and second printer controllers are connected to a common input of the printhead.

Optionally the printhead module is installed in a printer comprising:

a printhead comprising first and second elongate printhead modules,,the printhead modules being parallel to each other and being disposed end to end on either side of a join region;

at least first and second printer controllers configured to receive print data and process the print data to output dot data to the printhead, wherein the first printer controller outputs dot data only to the first printhead module and the second printer controller outputs dot data only to the second printhead module, wherein the printhead modules are configured such that no dot data passes between them.
Optionally the printhead module is installed in a printer comprising:

a printhead comprising first and second elongate printhead modules, the printhead modules being parallel to each other and being disposed end to end on either side of a join region, wherein the first printhead module is longer than the second printhead module;

at least first and second printer controllers configured to receive print data and process the print data to output dot data to the printhead, wherein: the first printer controller outputs dot data to both the first printhead module and the second printhead module; and the second printer controller outputs dot data only to the second printhead module.

Optionally the printhead module is installed in a printer comprising:

a printhead comprising first and second elongate printhead modules, the printhead modules being parallel to each other and being disposed end to end on either side of a join region, wherein the first printhead module is longer than the second printhead module;

at least first and second printer controllers configured to receive print data and process the print data to output dot data for the printhead, wherein: the fust printer controller outputs dot data to both the first printhead module and the second controller; and the second printer controller outputs dot data to the second printhead module, wherein the dot data output by the second printer controller includes dot data it generates and at least some of the dot data received from the first printer controller.

Optionally the printhead module is in communication with a printer controller for supplying dot data to at least one printhead module and at least partially compensating for errors in ink dot placement by at least one of a plurality of nozzles on the printhead module due to erroneous rotational displacement of the printhead module relative to a carrier, the printer being configured to:

access a correction factor associated with the at least one printhead module;

determine an order in which at least some of the dot data is supplied to at least one of the at least one printhead modules, the order being determined at least partly on the basis of the correction factor, thereby to at least partially compensate for the rotational displacement; and supply the dot data to the printhead module.

Optionally the printhead module is in communication with a printer controller for supplying dot data to a printhead module having a plurality of nozzles for expelling ink, the printhead module including a plurality of thermal sensors, each of the thermal sensors being configured to respond to a temperature at or adjacent at least one of the nozzles, the printer controller being configured to modify operation of at least some of the nozzles in response to the temperature rising above a first threshold.

Optionally the printhead module is in communication with a printer controller for controlling a head comprising at least one monolithic printhead module, the at least one printhead module having a plurality of rows of nozzles configured to extend, in use, across at least part of a printable pagewidth of the printhead, the nozzles in each row being grouped into at least first and second fire groups, the printhead module being configured to sequentially fire, for each row, the nozzles of each fire group, such that each nozzle in the sequence from each fire group is fired simultaneously with respective corresponding nozzles in the sequence in the other fire groups, wherein the nozzles are fired row by row such that the nozzles of each row are all fired before the nozzles of each subsequent row, wherein the printer controller is configured to provide one or more control signals that control the order of firing of the nozzles.

Optionally the printhead module is, in communication with a printer controller for outputting to a printhead module:

dot data to be printed with at least two different inks; and control data for controlling printing of the dot data;

the printer controller including at least one communication output, each or the communication output being configured to output at least some of the control data and at least some of the dot data for the at least two inks.
Optionally the printhead module includes at least one row of printhead nozzles, at least one row including at least one displaced row portion, the displacement of the row portion including a component in a direction normal to that of a pagewidth to be printed.

Optionally the printhead module is in communication with a printer controller for supplying print data to at least one printhead module capable of printing a maximum of n of channels of print data, the at least one printhead module being configurable into:, a first mode, in which the printhead module is configured to receive data for a first number of the channels; and a second mode, in which the printhead module is configured to receive print data for a second number of the channels, wherein the first number is greater than the second number;

wherein the printer controller is selectively configurable to supply dot data for the first and second modes.

Optionally the printhead module is in communication with a printer controller for supplying data to a printhead comprising a plurality of printhead modules, the printhead being wider than a reticle step used in forming the modules, the printhead comprising at least two types of the modules, wherein each type is determined by its geometric shape in plan.

Optionally the printhead module is used in conjunction with a printer controller for supplying one or more control signals to a printhead module, the printhead module including at least one row that comprises a plurality of sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, such that:

(a) a fire signal is provided to nozzles at a first and nth position in each set of nozzles;
(b) a fire signal is provided to the next inward pair of nozzles in each set;

(c) in the event n is an even number, step (b) is repeated until all of the nozzles in each set has been fired;
and (d) in the event n is an odd number, step (b) is repeated until all of the nozzles but a central nozzle in each set have been fired, and then the central nozzle is fired.

Optionally the printhead module is used in conjunction with a printer controller for supplying one or more control signals to a printhead module, the printhead module including at least one row that comprises a plurality of adjacent sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, the method comprising providing, for each set of nozzles, a fire signal in accordance with the sequence: [nozzle position 1, nozzle position n, nozzle position 2, nozzle position (n-1), ... , nozzle position x], wherein nozzle position x is at or adjacent the centre of the set of nozzles.

Optionally the printhead module is in communication with a printer controller for supplying dot data to a printhead module comprising at least first and second rows configured to print ink of a similar type or color, at least some nozzles in the first row being aligned with respective corresponding nozzles in the second row in a direction of intended media travel relative to the printhead, the printhead module being configurable such that the nozzles in the first and second pairs of rows are fired such that some dots output to print media are printed to by nozzles from the first pair of rows and at least some other dots output to print media are printed to by nozzles from the second pair of rows, the printer controller being configurable to supply dot data to the printhead module for printing.

Optionally the printhead module is in communication with a printer controller for supplying dot data to at least one printhead module, the at least one printhead module comprising a plurality of rows, each of the rows comprising a plurality of nozzles for ejec6ng ink, wherein the printhead module includes at least first and second rows configured to print ink of a similar type or color, the printer controller being configured to supply the dot data to the at least one printhead module such that, in the event a nozzle in the first row is faulty, a corresponding nozzle in the second row prints an ink dot at a position on print media at or adjacent a position where the faulty nozzle would otherwise have printed it.

Optionally the printhead module is in communication with a printer controller for receiving fust data and manipulating the first data to produce dot data to be printed, the print controller including at least two serial outputs for supplying the dot data to at least one printhead.

Optionally the printhead module further including:
at least one row of print nozzles;

at least first and second shift registers for shifting in dot data supplied from a data source, wherein each shift register feeds dot data to a group of nozzles, and wherein each of the groups of the nozzles is interleaved with at least one of the other groups of the nozzles.

Optionally the printhead module being capable of printing a maximum of n of channels of print data, the printhead being configurable into:

a first mode, in which the printhead is configured to receive print data for a first number of the channels;
and a second mode, in which the printhead is configured to receive print data for a second number of the channels, wherein the first number is greater than the second number.

Optionally a module further comprising a plurality of printhead modules including:
at least one row of print nozzles;

at least first and second shift registers for shifting in dot data supplied from a data source, wherein each shift register feeds dot data to a group of nozzles, and wherein each of the groups of the nozzles is interleaved with at least one of the other groups of the nozzles; and the printhead being wider than a reticle step used in forming the modules, the printhead comprising at least two types of the modules, wherein each type is determined by its geometric shape in plan.

Optionally the printhead module includes at least one row that comprises a plurality of sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, such that, for each set of nozzles, a fire signal is provided in accordance with the sequence: [nozzle position 1, nozzle position n, nozzle position 2, nozzle position (n-1), ... , nozzle position x], wherein nozzle position x is at or adjacent the centre of the set of nozzles.

Optionally the printhead module further includes at least one row that comprises a plurality of adjacent sets of n adjacent nozzles, each of the nozzles being configured to expel the ink in response to a fire signal, the printhead being configured to output ink from nozzles at a first and nth position in each set of nozzles, and then each next inward pair of nozzles in each set, until:

in the event n is an even number, all of the nozzles in each set has been fired; and in the event n is an odd number, all of the nozzles but a central nozzle in each set have been fired, and then to fire the central nozzle.

Optionally a printhead module for receiving dot data to be printed using at least two different inks and control data for controlling printing of the dot data, the printhead module including a communication input for receiving the dot data for the at least two colors and the control data.

Optionally a printhead module further includes at least one row of printhead nozzles, at least one row including at least one displaced row portion, the displacement of the row portion including a component in a direction normal to that of a pagewidth to be printed.

Optionally a printhead module having a plurality of rows of nozzles configured to extend, in use, across at least part of a printable pagewidth, the nozzles in each row being grouped into at least first and second fire groups, the printhead module being configured to sequentially fire, for each row, the nozzles of each fire group, such that each nozzle in the sequence from each fire group is fired simultaneously with respective corresponding nozzles in the sequence in the other fire groups, wherein the nozzles are fired row by row such that the nozzles of each row are all fired before the nozzles of each subsequent row.

Optionally a printhead module further comprising at least first and second rows configured to print ink of a similar type or color, at least some nozzles in the first row being aligned with respective corresponding nozzles in the second row in a direction of intended media travel relative to the printhead, the printhead module being configurable such that the nozzles in the first and second pairs of rows are fired such that some dots output to print media are printed to by nozzles from the first pair of rows and at least some other dots output to print media are printed to by nozzles from the second pair of rows.

Optionally a printhead module is in communication with a printer controller for providing data to a printhead module that includes:

at least one row of print nozzles;

at least first and second shift registers for shifting in dot data supplied from a data source, wherein each shift register feeds dot data to a group of nozzles, and wherein each of the groups of the nozzles is interleaved with at least one of the other groups of the nozzles.

Optionally a printhead module having a plurality of nozzles for expelling ink, the printhead module including a plurality of thermal sensors, each of the thermal sensors being configured to respond to a temperature at or adjacent at least one of the nozzles, the printhead module being configured to modify operation of the nozzles in response to the temperature rising above a first threshold.

Optionally a printhead module further comprising a plurality of rows, each of the rows comprising a plurality of nozzles for ejecting ink, wherein the printhead module includes at least first and second rows configured to print ink of a similar type or color, and being configured such that, in the event a nozzle in the first row is faulty, a corresponding nozzle in the second row prints an ink dot at a position on print media at or adjacent a position where the faulty nozzle would otherwise have printed it.

In a thirty first aspect the present invention provides a printer controller for providing data to a printhead module that includes:

at least one row of print nozzles;

at least first and second shift registers for shifting in dot data supplied from a data source, wherein each shift register feeds dot data to a group of nozzles, and wherein each of the groups of the nozzles is interleaved with at least one of the other groups of the nozzles.

Optionally there is a one to one con-espondence between the nozzles and respective elements of the first and second shift registers.

Optionally each of the shift registers supplies dot data to about half of the nozzles in a row.

Optionally the printer controller includes at least one pair of rows of the nozzles, the rows in each pair being offset in a direction parallel to the rows by half the intra-row nozzle spacing.

Optionally each of the at least two shift registers supplies dot data to at least some of the nozzles in at least the pair of rows.

Optionally the printer includes a plurality of the rows configured to print using at least two ink channels, the nozzles for each of the ink channels being fed the dot data from at least one pair of first and second registers.
Optionally the printhead module forms part of a printhead.

Optionally the printhead includes a plurality of the printhead modules and the printer controller is configured to supply data to a plurality of the modules.

Optionally the printhead is a pagewidth printhead comprising a plurality of the printhead modules.

Optionally the printer controller is for implementing a method of expelling ink from a printhead module including at least one row that comprises a plurality of sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, the method comprising the steps of:

(a) providing a fire signal to nozzles at a first and nth position in each set of nozzles;
(b) providing a fire signal to the next inward pair of nozzles in each set;

(c) in the event n is an even number, repeating step (b) until all of the nozzles in each set has been fired; and (d) in the event n is an odd number, repeating step (b) until all of the nozzles but a central nozzle in each set have been fired, and then firing the central nozzle.

Optionally the printer controller is manufactured in accordance with a method of manufacturing a plurality of printhead modules, at least some of which are capable of being combined in pairs to form bilithic pagewidth printheads, the method comprising the step of laying out each of the plurality of printhead modules on a wafer substrate, wherein at least one of the printhead modules is right-handed and at least another is left-handed.
Optionally the printer controller supplies data to a printhead module including:

at least one row of print nozzles;

at least two shift registers for shifting in dot data supplied from a data source to each of the at least one rows, wherein each print nozzle obtains dot data to be fired from an element of one of the shift registers.
Optionally the printer controller is installed in a printer comprising:

a printhead comprising at least a first elongate printhead module, the at least one printhead module including at least one row of print nozzles for expelling ink; and at least first and second printer controllers configured to receive print data and process the print data to output dot data to the printhead, wherein the first and second printer controllers are connected to a common input of the printhead.

Optionally the printer controller is installed in a printer comprising:

a printhead comprising first and second elongate printhead modules, the printhead modules being parallel to each other and being disposed end to end on either side of a join region;

at least first and second printer controllers configured to receive print data and process the print data to output dot data to the printhead, wherein the fust printer controller outputs dot data only to the first printhead module and the second printer controller outputs dot data only to the second printhead module, wherein the printhead modules are configured such that no dot data passes between them.

Optionally the printer controller is installed in a printer comprising:

a printhead comprising first and second elongate printhead modules, the printhead modules being parallel to each other and being disposed end to end on either side of a join region, wherein the first printhead module is longer than the second printhead module;

at least first and second printer controllers configured to receive print data and process the print data to output dot data to the printhead, wherein: the first printer controller outputs dot data to both the first printhead module and the second printhead module; and the second printer controller outputs dot data only to the second printhead module.

Optionally the printer controller is installed in a printer comprising:

a printhead comprising first and second elongate printhead modules, the printhead modules being parallel to each other and being disposed end to end on either side of a join region, wherein the first printhead module is longer than the second printhead module;

at least first and second printer controllers configured to receive print data and process the print data to output dot data for the printhead, wherein: the first printer controller outputs dot data to both the first printhead module and the second controller; and the second printer controller outputs dot data to the second printhead module, wherein the dot data output by the second printer controller includes dot data it generates and at least some of the dot data received from the first printer controller.

Optionally the printer controller supplies dot data to at least one printhead module and at least partially compensating for errors in ink dot placement by at least one of a plurality of nozzles on the printhead module due to erroneous rotational displacement of the printhead module relative to a carrier, the printer being configured to:
access a correction factor associated with the at least one printhead module;

determine an order in which at least some of the dot data is supplied to at least one of the at least one printhead modules, the order being determined at least partly on the basis of the correction factor, thereby to at least partially compensate for the rotational displacement; and supply the dot data to the printhead module.

Optionally the printer controller supplies dot data to a printhead module having a plurality of nozzles for expelling ink, the printhead module including a plurality of thermal sensors, each of the thermal sensors being configured to respond to a temperature at or adjacent at least one of the nozzles, the printer controller being configured to modify operation of at least some of the nozzles in response to the temperature rising above a first threshold.

Optionally the printer controller controls a printhead comprising at least one monolithic printhead module, the at least one printhead module having a plurality of rows of nozzles configured to extend, in use, across at least part of a printable pagewidth of the printhead, the nozzles in each row being grouped into at least first and second fire groups, the printhead module being configured to sequentially fire, for each row, the nozzles of each fire group, such that each nozzle in the sequence from each fire group is fired simultaneously with respective corresponding nozzles in the sequence in the other fire groups, wherein the nozzles are fired row by row such that the nozzles of each row are all fired before the nozzles of each subsequent row, wherein the printer controller is configured to provide one or more control signals that control the order of firing of the nozzles.

Optionally the printer controller outputs to a printhead module:

dot data to be printed with at least two different inks; and control data for controlling printing of the dot data;

the printer controller including at least one communication output, each or the communication output being configured to output at least some of the control data and at least some of the dot data for the at least two inks.
Optionally the printer controller supplies data to a printhead module including at least one row of printhead nozzles, at least one row including at least one displaced row portion, the displacement of the row portion including a component in a direction normal to that of a pagewidth to be printed.

Optionally the printer controller supplies print data to at least one printhead module capable of printing a maximum of n of channels of print data, the at least one printhead module being configurable into:

a first mode, in which the printhead module is configured to receive data for a first number of the channels; and a second mode, in which the printhead module is configured to receive print data for a second number of the channels, wherein the first number is greater than the second number;

wherein the printer controller is selectively configurable to supply dot data for the first and second modes.
Optionally the printer controller supplies data to a printhead comprising a plurality of printhead modules, the printhead being wider than a reticle step used in forming the modules, the printhead comprising at least two types of the modules, wherein each type is determined by its geometric shape in plan.

Optionally the printer controller supplies one or more control signals to a printhead module, the printhead module including at least one row that comprises a plurality of adjacent sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, the method comprising providing, for each set of nozzles, a fire signal in accordance with the sequence: [nozzle position 1, nozzle position n, nozzle position 2, nozzle position (n-1), ... , nozzle position x], wherein nozzle position x is at or adjacent the centre of the set of nozzles.

Optionally the printer controller supplies dot data to a printhead module comprising at least first and second rows configured to print ink of a similar type or color, at least some nozzles in the first row being aligned with respective corresponding nozzles in the second row in a direction of intended media travel relative to the printhead, the printhead module being configurable such that the nozzles in the first and second pairs of rows are fired such that some dots output to print media are printed to by nozzles from the first pair of rows and at least some other dots output to print media are printed to by nozzles from the second pair of rows, the printer controller being configurable to supply dot data to the printhead module for printing.

Optionally the printer controller supplies dot data to at least one printhead module, the at least one printhead module comprising a plurality of rows, each of the rows comprising a plurality of nozzles for ejecting ink, wherein the printhead module includes at least first and second rows configured to print ink of a similar type or color, the printer controller being configured to supply the dot data to the at least one printhead module such that, in the event a nozzle in the first row is faulty, a corresponding nozzle in the second row prints an ink dot at a position on print media at or adjacent a position where the faulty nozzle would otherwise have printed it.

Optionally the printer controller receives first data and manipulating the first data to produce dot data to be printed, the print controller including at least two serial outputs for supplying the dot data to at least one printhead.
Optionally the printer controller supplies data to a printhead module including:

at least one row of print nozzles;

at least first and second shift registers for shifting in dot data supplied from a data source, wherein each shift register feeds dot data to a group of nozzles, and wherein each of the groups of the nozzles is interleaved with at least one of the other groups of the nozzles.

Optionally the printer controller supplies data to a printhead capable of printing a maximum of n of channels of print data, the printhead being configurable into:

a first mode, in which the printhead is configured to receive print data for a first number of the channels;
and a second mode, in which the printhead is configured to receive print data for a second number of the channels, wherein the first number is greater than the second number.

Optionally the printer controller supplies data to a printhead comprising a plurality of printhead modules, the printhead being wider than a reticle step used in forming the modules, the printhead comprising at least two types of the modules, wherein each type is determined by its geometric shape in plan.

Optionally the printer controller supplies data to a printhead module including at least one row that comprises a plurality of sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, such that, for each set of nozzles, a fire signal is provided in accordance with the sequence: [nozzle position 1, nozzle position n, nozzle position 2, nozzle position (n-1), ... , nozzle position x], wherein nozzle position x is at or adjacent the centre of the set of nozzles.

Optionally the printer controller supplies data to a printhead module including at least one row that comprises a plurality of adjacent sets of n adjacent nozzles, each of the nozzles being configured to expel the ink in response to a fire signal, the printhead being configured to output ink from nozzles at a first and nth position in each set of nozzles, and then each next inward pair of nozzles in each set, until:

in the event n is an even number, all of the nozzles in each set has been fired; and in the event n is an odd number, all of the nozzles but a central nozzle in each set have been fired, and then to fire the central nozzle.

Optionally the printer controller supplies data to a printhead module for receiving dot data to be printed using at least two different inks and control data for controlling printing of the dot data, the printhead module including a communication input for receiving the dot data for the at least two colors and the control data.

Optionally the printer controller supplies data to a printhead module including at least one row of printhead nozzles, at least one row including at least one displaced row portion, the displacement of the row portion including a component in a direction normal to that of a pagewidth to be printed.

Optionally the printer controller supplies data to a printhead module having a plurality of rows of nozzles configured to extend, in use, across at least part of a printable pagewidth, the nozzles in each row being grouped into at least first and second fire groups, the printhead module being configured to sequentially fire, for each row, the nozzles of each fire group, such that each nozzle in the sequence from each fire group is fired simultaneously with respective corresponding nozzles in the sequence in the other fire groups, wherein the nozzles are fired row by row such that the nozzles of each row are all fired before the nozzles of each subsequent row.

Optionally the printer controller supplies data to a printhead module comprising at least first and second rows configured to print ink of a similar type or color, at least some nozzles in the first row being aligned with respective corresponding nozzles in the second row in a direction of intended media travel relative to the printhead, the printhead module being configurable such that the nozzles in the first and second pairs of rows are fired such that some dots output to print media are printed to by nozzles from the first pair of rows and at least some other dots output to print media are printed to by nozzles from the second pair of rows.

Optionally the printer controller supplies data to a printhead module that includes:
at least one row of print nozzles;

at least first and second shift registers for shifting in dot data supplied from a data source, wherein each shift register feeds dot data to a group of nozzles, and wherein each of the groups of the nozzles is interleaved with at least one of the other groups of the nozzles.

Optionally the printer controller supplies data to a printhead module having a plurality of nozzles for expelling ink, the printhead module including a plurality of thermal sensors, each of the thermal sensors being configured to respond to a temperature at or adjacent at least one of the nozzles, the printhead module being configured to modify operation of the nozzles in response to the temperature rising above a first threshold.

Optionally the printer controller supplies data to a printhead module comprising a plurality of rows, each of the rows comprising a plurality of nozzles for ejecting ink, wherein the printhead module includes at least first and second rows configured to print ink of a similar type or color, and being configured such that, in the event a nozzle in the first row is faulty, a corresponding nozzle in the second row prints an ink dot at a position on print media at or adjacent a position where the faulty nozzle would otherwise have printed it.

In a thirty second aspect the present invention provides a printhead module having a plurality of nozzles for expelling ink, the printhead module including a plurality of thermal sensors, each of the thermal sensors being configured to respond to a temperature at or adjacent at least one of the nozzles, the printhead module being configured to modify operation of the nozzles in response to the temperature rising above a first threshold.

Optionally the printhead module is configured to modify the operation of the nozzles at or adjacent the at least one thermal sensor, such that operation of nozzles not at or adjacent the at least one thermal sensor is not modified.

Optionally each thermal sensor is associated with a predetermined group of the nozzles, the nozzles in the predetermined group being those for which the operation is modified.

Optionally each thermal sensor is associated with a single nozzle.
Optionally the modification includes preventing operation of the nozzle.

Optionally the modification includes preventing operation of the nozzle for a predetenmined period.

Optionally the modification includes preventing operation of the nozzle until the temperature drops below a second threshold.

Optionally the second threshold is lower than the first threshold.

Optionally the second threshold is the same as the first threshold.

Optionally the temperature is not determined explicitly by the at least one thermal sensor or the module.

Optionally the printhead module is a thermal inkjet printhead module and each of the nozzles includes a thermal ink ejection mechanism.

Optionally the thermal sensor comprises at least part of one of the thermal inkjet mechanisms.
Optionally the thermal sensor comprises a heating element.

Optionally the thermal sensor determines the temperature by determining a resistance of the heating element.

Optionally printhead module according to claim 1, configured to:

output thermal information from the at least one thermal sensor to a controller; and receive control information back from the controller, the control information being indicative of the modification to make to the operation of the one or more nozzles.

Optionally the printhead module further including a plurality of data latches, the data latches being configured to provide dot data to respective ones of the nozzles, at least some of the data latches being configured to receive thermal signals from respective ones of the thermal sensors during an acquisition period.

Optionally the data latches are configured to form a shift register, the shift register being configured to:
shift the print data in during a print load phase;

sample the signals from the thermal sensors during a temperature load phase;
and shift the thermal signals out during an output phase.

Optionally the output phase coincides with a subsequent print load phase.

Optionally the printhead module further including logic circuitry configured to perform a bitwise operation on:
each thermal signal as it is clocked out of the shift register; and each piece of dot data to be clocked into the shift register, such that when a thermal signal is indicative of a thermal problem with a nozzle, the logic circuitry prevents loading of data that would cause firing of that nozzle.

Optionally the logic circuitry includes an AND circuit that receives as inputs the dot data and the thermal signal corresponding to the nozzle for which the dot data is intended, an output of the AND circuit being in communication with an input of the shift register.

Optionally the printhead module is configured to receive dot data to which a method of at least partially compensating for errors in ink dot placement by at least one of a plurality of nozzles due to erroneous rotational displacement of a printhead module relative to a carrier has been applied, the nozzles being disposed on the printhead module, the method comprising the steps of:

(a) determining the rotational displacement;

(b) determining at least one correction factor that at least partially compensates for the ink dot displacement;
and (c) using the correction factor to alter the output of the ink dots to at least partially compensate for the rotational displacement.

Optionally the printhead module is configured to receive dot data to which a method of expelling ink has been applied, the method being applied to a printhead module including at least one row that comprises a plurality of adjacent sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, the method comprising providing, for each set of nozzles, a fire signal in accordance with the sequence: [nozzle position 1, nozzle position n, nozzle position 2, nozzle position (n-1), ... , nozzle position x], wherein nozzle position x is at or adjacent the centre of the set of nozzles.

Optionally the printhead module is configured to receive dot data to which a method of expelling ink has been applied, the method being applied to a printhead module including at least one row that comprises a plurality of sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, the method comprising the steps of (a) providing a fire signal to nozzles at a first and nth position in each set of nozzles;
(b) providing a fire signal to the next inward pair of nozzles in each set;

(c) in the event n is an even number, repeating step (b) until all of the nozzles in each set has been fired; and (d) in the event n is an odd number, repeating step (b) until all of the nozzles but a central nozzle in each set have been fired, and then firing the central nozzle.

Optionally the printhead module is manufactured in accordance with a method of manufacturing a plurality of printhead modules, at least some of which are capable of being combined in pairs to form bilithic pagewidth printheads, the method comprising the step of laying out each of the plurality of printhead modules on a wafer substrate, wherein at least one of the printhead modules is right-handed and at least another is left-handed.
Optionally the printhead module further including:

at least one row of print nozzles;

at least two shift registers for shifting in dot data supplied from a data source to each of the at least one rows, wherein each print nozzle obtains dot data to be fired from an element of one of the shift registers.

Optionally the printhead module is installed in a printer comprising:

a printhead comprising at least the first elongate printhead module, the at least one printhead module including at least one row of print nozzles for expelling ink; and at least first and second printer controllers configured to receive print data and process the print data to output dot data to the printhead, wherein the first and second printer controllers are connected to a common input of the printhead.

Optionally the printhead module is installed in a printer comprising:

a printhead comprising first and second elongate printhead modules, the printhead modules being parallel to each other and being disposed end to end on either side of a join region;

at least first and second printer controllers configured to receive print data and process the print data to output dot data to the printhead, wherein the first printer controller outputs dot data only to the first printhead module and the second printer controller outputs dot data only to the second printhead module, wherein the printhead modules are configured such that no dot data passes between them.
Optionally the printhead module is installed in a printer comprising:

a printhead comprising first and second elongate printhead modules, the printhead modules being parallel to each other and being disposed end to end on either side of a join region, wherein the first printhead module is longer than the second printhead module;

at least first and second printer controllers configured to receive print data and process the print data to output dot data to the printhead, wherein: the first printer controller outputs dot data to both the first printhead module and the second printhead module; and the second printer controller outputs dot data only to the second printhead module.

Optionally the printhead module is installed in a printer comprising:

a printhead comprising first and second elongate printhead modules, the printhead modules being parallel to each other and being disposed end to end on either side of a join region, wherein the first printhead module is longer than the second printhead module;

at least first and second printer controllers configured to receive print data and process the print data to output dot data for the printhead, wherein: the first printer controller outputs dot data to both the first printhead module and the second controller; and the second printer controller outputs dot data to the second printhead module, wherein the dot data output by the second printer controller includes dot data it generates and at least some of the dot data received from the first printer controller.

Optionally the printhead module is in communication with a printer controller for supplying dot data to at least one printhead module and at least partially compensating for errors in ink dot placement by at least one of a plurality of nozzles on the printhead module due to erroneous rotational displacement of the printhead module relative to a carrier, the printer being configured to:

access a correction factor associated with the at least one printhead module;

determine an order in which at least some of the dot data is supplied to at least one of the at least one printhead modules, the order being deternuned at least partly on the basis of the correction factor, thereby to at least partially compensate for the rotational displacement; and supply the dot data to the printhead module.

Optionally the printhead module is in communication with a printer controller for supplying dot data to a printhead module having a plurality of nozzles for expelling ink, the printhead module including a plurality of thermal sensors, each of the thermal sensors being configured to respond to a temperature at or adjacent at least one of the nozzles, the printer controller being configured to modify operation of at least some of the nozzles in response to the temperature rising above a first threshold.

Optionally the printhead module is in communication with a printer controller for controlling a head comprising at least one monolithic printhead module, the at least one printhead module having a plurality of rows of nozzles configured to extend, in use, across at least part of a printable pagewidth of the printhead, the nozzles in each row being grouped into at least first and second fire groups, the printhead module being configured to sequentially fire, for each row, the nozzles of each fire group, such that each nozzle in the sequence from each fire group is fired simultaneously with respective corresponding nozzles in the sequence in the other fire groups, wherein the nozzles are fired row by row such that the nozzles of each row are all fired before the nozzles of each subsequent row, wherein the printer controller is configured to provide one or more control signals that control the order of firing of the nozzles.

Optionally the printhead module is, in communication with a printer controller for outputting to a printhead module:

dot data to be printed with at least two different inks; and control data for controlling printing of the dot data;

the printer controller including at least one communication output, each or the communication output being configured to output at least some of the control data and at least some of the dot data for the at least two inks.

Optionally the printhead module includes at least one row of printhead nozzles, at least one row including at least one displaced row portion, the displacement of the row portion including a component in a direction normal to that of a pagewidth to be printed.

Optionally the printhead module is in communication with a printer controller for supplying print data to at least one printhead module capable of printing a maximum of n of channels of print data, the at least one printhead module being configurable into:

a fust mode, in which the printhead module is configured to receive data for a first number of the channels; and a second mode, in which the printhead module is configured to receive print data for a second number of the channels, wherein the first number is greater than the second number;

wherein the printer controller is selectively configurable to supply dot data for the first and second modes.
Optionally the printhead module is in communication with a printer controller for supplying data to a printhead comprising a plurality of printhead modules, the printhead being wider than a reticle step used in fornung the modules, the printhead comprising at least two types of the modules, wherein each type is determined by its geometric shape in plan.

Optionally the printhead module is used in conjunction with a printer controller for supplying one or more control signals to a printhead module, the printhead module including at least one row that comprises a plurality of sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, such that:

(a) a fire signal is provided to nozzles at a first and nth position in each set of nozzles;
(b) a fire signal is provided to the next inward pair of nozzles in each set;

(c) in the event n is an even number, step (b) is repeated until all of the nozzles in each set has been fired;
and (d) in the event n is an odd number, step (b) is repeated until all of the nozzles but a central nozzle in each set have been fired, and then the central nozzle is fired.

Optionally the printhead module is used in conjunction with a printer controller for supplying one or more control signals to a printhead module, the printhead module including at least one row that comprises a plurality of adjacent sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, the method comprising providing, for each set of nozzles, a fire signal in accordance with the sequence: [nozzle position 1, nozzle position n, nozzle position 2, nozzle position (n-1), ... , nozzle position x], wherein nozzle position x is at or adjacent the centre of the set of nozzles.

Optionally the printhead module is in communication with a printer controller for supplying dot data to a printhead module comprising at least first and second rows configured to print ink of a similar type or color, at least some nozzles in the first row being aligned with respective corresponding nozzles in the second row in a direction of intended media travel relative to the printhead, the printhead module being configurable such that the nozzles in the first and second pairs of rows are fired such that some dots output to print media are printed to by nozzles from the first pair of rows and at least some other dots output to print media are printed to by nozzles from the second pair of rows, the printer controller being configurable to supply dot data to the printhead module for printing.

Optionally the printhead module is in communication with a printer controller for supplying dot data to at least one printhead module, the at least one printhead module comprising a plurality of rows, each of the rows comprising a plurality of nozzles for ejecting ink, wherein the printhead module includes at least first and second rows configured to print ink of a similar type or color, the printer controller being configured to supply the dot data to the at least one printhead module such that, in the event a nozzle in the fust row is faulty, a corresponding nozzle in the second row prints an ink dot at a position on print media at or adjacent a position where the faulty nozzle would otherwise have printed it.

Optionally the printhead module is in communication with a printer controller for receiving first data and manipulating the first data to produce dot data to be printed, the print controller including at least two serial outputs for supplying the dot data to at least one printhead.

Optionally the printhead module further including:
at least one row of print nozzles;

at least first and second shift registers for shifting in dot data supplied from a data source, wherein each shift register feeds dot data to a group of nozzles, and wherein each of the groups of the nozzles is interleaved with at least one of the other groups of the nozzles.

Optionally the printhead module being capable of printing a maximum of n of channels of print data, the printhead being configurable into:

a first mode, in which the printhead is configured to receive print data for a first number of the channels;
and a second mode, in which the printhead is configured to receive print data for a second number of the channels, wherein the first number is greater than the second number.

Optionally a module further comprising a plurality of printhead modules including:
at least one row of print nozzles;

at least first and second shift registers for shifting in dot data supplied from a data source, wherein each shift register feeds dot data to a group of nozzles, and wherein each of the groups of the nozzles is interleaved with at least one of the other groups of the nozzles; and the printhead being wider than a reticle step used in forming the modules, the printhead comprising at least two types of the modules, wherein each type is determined by its geometric shape in plan.

Optionally the printhead module includes at least one row that comprises a plurality of sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, such that, for each set of nozzles, a fire signal is provided in accordance with the sequence: [nozzle position 1, nozzle position n, nozzle position 2, nozzle posi6on (n-1), ... , nozzle position x], wherein nozzle position x is at or adjacent the centre of the set of nozzles.

Optionally the printhead module further includes at least one row that comprises a plurality of adjacent sets of n adjacent nozzles, each of the nozzles being configured to expel the ink in response to a fire signal, the printhead being configured to output ink from nozzles at a first and nth position in each set of nozzles, and then each next inward pair of nozzles in each set, until:

in the event n is an even number, all of the nozzles in each set has been fired; and in the event n is an odd number, all of the nozzles but a central nozzle in each set have been fired, and then to fire the central nozzle.

Optionally a printhead module for receiving dot data to be printed using at least two different inks and control data for controlling printing of the dot data, the printhead module including a communication input for receiving the dot data for the at least two colors and the control data.

Optionally a printhead module further includes at least one row of printhead nozzles, at least one row including at least one displaced row portion, the displacement of the row portion including a component in a direction normal to that of a pagewidth to be printed.

Optionally a printhead module having a plurality of rows of nozzles configured to extend, in use, across at least part of a printable pagewidth, the nozzles in each row being grouped into at least first and second fire groups, the printhead module being configured to sequentially fire, for each row, the nozzles of each fire group, such that each nozzle in the sequence from each fire group is fired simultaneously with respective corresponding nozzles in the sequence in the other fire groups, wherein the nozzles are fired row by row such that the nozzles of each row are all fired before the nozzles of each subsequent row.

Optionally a printhead module further comprising at least first and second rows configured to print ink of a similar type or color, at least some nozzles in the first row being aligned with respective corresponding nozzles in the second row in a direction of intended media travel relative to the printhead, the printhead module being configurable such that the nozzles in the first and second pairs of rows are fired such that some dots output to print media are printed to by nozzles from the fust pair of rows and at least some other dots output to print media are printed to by nozzles from the second pair of rows.

Optionally a printhead module is in communication with a printer controller for providing data to a printhead module that includes:

at least one row of print nozzles;

at least first and second shift registers for shifting in dot data supplied from a data source, wherein each shift register feeds dot data to a group of nozzles, and wherein each of the groups of the nozzles is interleaved with at least one of the other groups of the nozzles.

Optionally a printhead module having a plurality of nozzles for expelling ink, the printhead module including a plurality of thermal sensors, each of the thermal sensors being configured to respond to a temperature at or adjacent at least one of the nozzles, the printhead module being configured to modify operation of the nozzles in response to the temperature rising above a first threshold.

Optionally a printhead module further comprising a plurality of rows, each of the rows comprising a plurality of nozzles for ejecting ink, wherein the printhead module includes at least first and second rows configured to print ink of a similar type or color, and being configured such that, in the event a nozzle in the first row is faulty, a corresponding nozzle in the second row prints an ink dot at a position on print media at or adjacent a position where the faulty nozzle would otherwise have printed it.

Optionally the printhead module further including a logic circuit accepting as inputs a masking signal and the thermal signal corresponding to the nozzle for which the dot data is intended, the logic circuit outputting the thermal signal to the input of the AND circuit in reliance on a value of the masking signal.

Optionally the value of the masking signal enables masking of the thermal signal for at least one nozzle position, including the nozzle for which the current dot data is intended.

Optionally the value of the masking signal enables masking of the thermal signal for a plurality of nozzle positions corresponding to a region of the printhead associated the nozzle for which the current dot data is intended.

Optionally the value of the masking signal enables masking of the thermal signal for all of the nozzle positions of the printhead.

In a thirty third aspect the present invention provides a printhead module comprising a plurality of rows, each of the rows comprising a plurality of nozzles for ejecting ink, wherein the printhead module includes at least first and second rows configured to print ink of a similar type or color, and being configured such that, in the event a nozzle in the first row is faulty, a corresponding nozzle in the second row prints an ink dot at a position on print media at or adjacent a position where the faulty nozzle would otherwise have printed it.

Optionally each nozzle in the first row is paired with a nozzle in the second row, such that each pair of nozzles is aligned in an intended direction of print media travel relative to the printhead module.

Optionally each printhead module further including a plurality of sets of the first and second rows.

Optionally each of the sets of the first and second rows is configured to print in a single color or ink type.
Optionally each of the rows includes an odd and an even sub-row, the odd and even sub-rows being offset with respect to each other in a direction of print media travel relative to the printhead in use.

Optionally the odd and even sub-rows are transversely offset with respect to each other.

Optionally printhead comprising a plurality of printhead modules wherein each nozzle in the first row is paired with a nozzle in the second row, such that each pair of nozzles is aligned in an intended direction of print media travel relative to the printhead module.

Optionally printhead comprising a plurality of printhead modules each of the sets of the fust and second rows is configured to print in a single color or ink type.

Optionally the printhead being a pagewidth printhead.

Optionally the printhead module is configured to receive dot data to which a method of at least partially compensating for errors in ink dot placement by at least one of a plurality of nozzles due to erroneous rotational displacement of a printhead module relative to a camer has been applied, the nozzles being disposed on the printhead module, the method comprising the steps of:
(a) determining the rotational displacement;

(b) determining at least one correction factor that at least partially compensates for the ink dot displacement;
and (c) using the correction factor to alter the output of the ink dots to at least partially compensate for the rotational displacement.

Optionally the printhead module is configured to receive dot data to which a method of expelling ink has been applied, the method being applied to a printhead module including at least one row that comprises a plurality of adjacent sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a;fire signal, the method comprising providing, for each set of nozzles, a fire signal in accordance with the sequence: [nozzle position 1, nozzle position n, nozzle position 2, nozzle position (n-1), ... , nozzle position x], wherein nozzle position x is at or adjacent the centre of the set of nozzles.

Optionally the printhead module is configured to receive dot data to which a method of expelling ink has been applied, the method being applied to a printhead module including at least one row that comprises a plurality of sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, the method comprising the steps of:

(a) providing a fire signal to nozzles at a first and nth position in each set of nozzles;
(b) providing a fire signal to the next inward pair of nozzles in each set;

(c) in the event n is an even number, repeating step (b) until all of the nozzles in each set has been fired; and (d) in the event n is an odd number, repeating step (b) until all of the nozzles but a central nozzle in each set have been fired, and then firing the central nozzle.

Optionally the printhead module is manufactured in accordance with a method of manufacturing a plurality of printhead modules, at least some of which are capable of being combined in pairs to form bilithic pagewidth printheads, the method comprising the step of laying out each of the plurality of printhead modules on a wafer substrate, wherein at least one of the printhead modules is right-handed and at least another is left-handed.
Optionally the printhead module further including:

at least one row of print nozzles;

at least two shift registers for shifting in dot data supplied from a data source to each of the at least one rows, wherein each print nozzle obtains dot data to be fired from an element of one of the shift registers.
Optionally the printhead module is installed in a printer comprising:

a printhead comprising at least the first elongate printhead module, the at least one printhead module including at least one row of print nozzles for expelling ink; and at least first and second printer controllers configured to receive print data and process the print data to output dot data to the printhead, wherein the first and second printer controllers are connected to a common input of the printhead.

Optionally the printhead module is installed in a printer comprising:

a printhead comprising first and second elongate printhead modules, the printhead modules being parallel to each other and being disposed end to end on either side of a join region;

at least first and second printer controllers configured to receive print data and process the print data to output dot data to the printhead, wherein the fust printer controller outputs dot data only to the first printhead module and the second printer controller outputs dot data only to the second printhead module, wherein the printhead modules are configured such that no dot data passes between them.
Optionally the printhead module is installed in a printer comprising:

a printhead comprising first and second elongate printhead modules, the printhead modules being parallel to each other and being disposed end to end on either side of a join region, wherein the first printhead module is longer than the second printhead module;

at least first and second printer controllers configured to receive print data and process the print data to output dot data to the printhead, wherein: the first printer controller outputs dot data to both the first printhead module and the second printhead module; and the second printer controller outputs dot data only to the second printhead module.

Optionally the printhead module is installed in a printer comprising:

a printhead comprising first and second elongate printhead modules, the printhead modules being parallel to each other and being disposed end to end on either side of a join region, wherein the first printhead module is longer than the second printhead module;

at least first and second printer controllers configured to receive print data and process the print data to output dot data for the printhead, wherein: the first printer controller outputs dot data to both the first printhead module and the second controller; and the second printer controller outputs dot data to the second printhead module, wherein the dot data output by the second printer controller includes dot data it generates and at least some of the dot data received from the first printer controller.

Optionally the printhead module is in communication with a printer controller for supplying dot data to at least one printhead module and at least partially compensating for errors in ink dot placement by at least one of a plurality of nozzles on the printhead module due to erroneous rotational displacement of the printhead module relative to a carrier, the printer being configured to:

access a correction factor associated with the at least one printhead module;

determine an order in which at least some of the dot data is supplied to at least one of the at least one printhead modules, the order being determined at least partly on the basis of the correction factor, thereby to at least partially compensate for the rotational displacement; and supply the dot data to the printhead module.

Optionally the printhead module is in communication with a printer controller for supplying dot data to a printhead module having a plurality of nozzles for expelling ink, the printhead module including a plurality of thermal sensors, each of the thermal sensors being configured to respond to a temperature at or adjacent at least one of the nozzles, the printer controller being configured to modify operation of at least some of the nozzles in response to the temperature rising above a first threshold.

Optionally the printhead module is in communication with a printer controller for controlling a head comprising at least one monolithic printhead module, the at least one printhead module having a plurality of rows of nozzles configured to extend, in use, across at least part of a printable pagewidth of the printhead, the nozzles in each row being grouped into at least first and second fire groups, the printhead module being configured to sequentially fire, for each row, the nozzles of each fire group, such that each nozzle in the sequence from each fire group is fired simultaneously with respective corresponding nozzles in the sequence in the other fire groups, wherein the nozzles are fired row by row such that the nozzles of each row are all fired before the nozzles of each subsequent row, wherein the printer controller is configured to provide one or more control signals that control the order of firing of the nozzles.

Optionally the printhead module is, in communication with a printer controller for outputting to a printhead module:

dot data to be printed with at least two different inks; and control data for controlling printing of the dot data;

the printer controller including at least one communication output, each or the communication output being configured to output at least some of the control data and at least some of the dot data for the at least two inks.

Optionally the printhead module includes at least one row of printhead nozzles, at least one row including at least one displaced row portion, the displacement of the row portion including a component in a direction normal to that of a pagewidth to be printed.

Optionally the printhead module is in communication with a printer controller for supplying print data to at least one printhead module capable of printing a maximum of n of channels of print data, the at least one printhead module being configurable into:

a first mode, in which the printhead module is configured to receive data for a fust number of the channels; and a second mode, in which the printhead module is configured to receive print data for a second number of the channels, wherein the first number is greater than the second number;

wherein the printer controller is selectively configurable to supply dot data for the first and second modes.

Optionally the printhead module is in communication with a printer controller for supplying data to a printhead comprising a plurality of printhead modules, the printhead being wider than a reticle step used in forming the modules, the printhead comprising at least two types of the modules, wherein each type is determined by its geometric shape in plan.

Optionally the printhead module is used in conjunction with a printer controller for supplying one or more control signals to a printhead module, the printhead module including at least one row that comprises a plurality of sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, such that:

(a) a fire signal is provided to nozzles at a first and nth position in each set of nozzles;
(b) a fire signal is provided to the next inward pair of nozzles in each set;

(c) in the event n is an even number, step (b) is repeated until all of the nozzles in each set has been fired;
and (d) in the event n is an odd number, step (b) is repeated until all of the nozzles but a central nozzle in each set have been fired, and then the central nozzle is fired.

Optionally the printhead module is used in conjunction with a printer controller for supplying one or more control signals to a printhead module, the printhead module including at least one row that comprises a plurality of adjacent sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, the method comprising providing, for each set of nozzles, a fire signal in accordance with the sequence: [nozzle position 1, nozzle position n, nozzle position 2, nozzle position (n-1), ... , nozzle position x], wherein nozzle position x is at or adjacent the centre of the set of nozzles.

Optionally the printhead module is in communication with a printer controller for supplying dot data to a printhead module comprising at least first and second rows configured to print ink of a similar type or color, at least some nozzles in the fust row being aligned with respective corresponding nozzles in the second row in a direction of intended media travel relative to the printhead, the printhead module being configurable such that the nozzles in the first and second pairs of rows are fired such that some dots output to print media are printed to by nozzles from the first pair of rows and at least some other dots output to print media are printed to by nozzles from the second pair of rows, the printer controller being configurable to supply dot data to the printhead module for printing.

Optionally the printhead module is in communication with a printer controller for supplying dot data to at least one printhead module, the at least one printhead module comprising a plurality of rows, each of the rows comprising a plurality of nozzles for ejecting ink, wherein the printhead module includes at least first and second rows configured to print ink of a similar type or color, the printer controller being configured to supply the dot data to the at least one printhead module such that, in the event a nozzle in the first row is faulty, a corresponding nozzle in the second row prints an ink dot at a position on print media at or adjacent a position where the faulty nozzle would otherwise have printed it.

Optionally the printhead module is in communication with a printer controller for receiving first data and manipulating the first data to produce dot data to be printed, the print controller including at least two serial outputs for supplying the dot data to at least one printhead.

Optionally the printhead module fiuther including:
at least one row of print nozzles;

at least first and second shift registers for shifting in dot data supplied from a data source, wherein each shift register feeds dot data to a group of nozzles, and wherein each of the groups of the nozzles is interleaved with at least one of the other groups of the nozzles.

Optionally the printhead module being capable of printing a maximum of n of channels of print data, the printhead being configurable into:

a first mode, in which the printhead is configured to receive print data for a first number of the channels;
and a second mode, in which the printhead is configured to receive print data for a second number of the channels, wherein the first number is greater than the second number.

Optionally a module further comprising a plurality of printhead modules including:
at least one row of print nozzles;

at least first and second shift registers for shifting in dot data supplied from a data source, wherein each shift register feeds dot data to a group of nozzles, and wherein each of the groups of the nozzles is interleaved with at least one of the other groups of the nozzles; and the printhead being wider than a reticle step used in forming the modules, the printhead comprising at least two types of the modules, wherein each type is determined by its geometric shape in plan.

Optionally the printhead module includes at least one row that comprises a plurality of sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, such that, for each set of nozzles, a fire signal is provided in accordance with the sequence: [nozzle position 1, nozzle position n, nozzle position 2, nozzle position (n-1), ... , nozzle position x], wherein nozzle position x is at or adjacent the centre of the set of nozzles.

Optionally the printhead module further includes at least one row that comprises a plurality of adjacent sets of n adjacent nozzles, each of the nozzles being configured to expel the ink in response to a fire signal, the printhead being configured to output ink from nozzles at a first and nth position in each set of nozzles, and then each next inward pair of nozzles in each set, until:

in the event n is an even number, all of the nozzles in each set has been fired; and in the event n is an odd number, all of the nozzles but a central nozzle in each set have been fired, and then to fire the central nozzle.

Optionally a printhead module for receiving dot data to be printed using at least two different inks and control data for controlling printing of the dot data, the printhead module including a communication input for receiving the dot data for the at least two colors and the control data.

Optionally a printhead module further includes at least one row of printhead nozzles, at least one row including at least one displaced row portion, the displacement of the row portion including a component in a direction normal to that of a pagewidth to be printed.

Optionally a printhead module having a plurality of rows of nozzles configured to extend, in use, across at least part of a printable pagewidth, the nozzles in each row being grouped into at least first and second fire groups, the printhead module being configured to sequentially fire, for each row, the nozzles of each fire group, such that each nozzle in the sequence from each fire group is fired simultaneously with respective corresponding nozzles in the sequence in the other fire groups, wherein the nozzles are fired row by row such that the nozzles of each row are all fired before the nozzles of each subsequent row.

Optionally a printhead module further comprising at least first and second rows configured to print ink of a similar type or color, at least some nozzles in the first row being aligned with respective corresponding nozzles in the second row in a direction of intended media travel relative to the printhead, the printhead module being configurable such that the nozzles in the first and second pairs of rows are fired such that some dots output to print media are printed to by nozzles from the first pair of rows and at least some other dots output to print media are printed to by nozzles from the second pair of rows.

Optionally a printhead module is in communication with a printer controller for providing data to a printhead module that includes:

at least one row of print nozzles;

at least first and second shift registers for shifting in dot data supplied from a data source, wherein each shift register feeds dot data to a group of nozzles, and wherein each of the groups of the nozzles is interleaved with at least one of the other groups of the nozzles.

Optionally a printhead module having a plurality of nozzles for expelling ink, the printhead module including a plurality of thermal sensors, each of the thermal sensors being configured to respond to a temperature at or adjacent at least one of the nozzles, the printhead module being configured to modify operation of the nozzles in response to the temperature rising above a first threshold.

Optionally a printhead module further comprising a plurality of rows, each of the rows comprising a plurality of nozzles for ejecting ink, wherein the printhead module includes at least first and second rows configured to print ink of a similar type or color, and being configured such that, in the event a nozzle in the first row is faulty, a corresponding nozzle in the second row prints an ink dot at a position on print media at or adjacent a position where the faulty nozzle would otherwise have printed it.

In a thirty fourth aspect the present invention provides a first entity configured to authenticate a digital signature supplied by a second entity, wherein one of the entities includes a base key and the other of the entities includes a variant key and a bit-pattern, the variant key being based on the result of applying a one way function to the base key and the bit-pattern, the digital signature having been generated by the second entity using its key to digitally signing at least part of data to be authenticated, the first entity being configured to:

(a) receive the digital signature from the second entity;
(b) receive the data; and (c) authenticate the digital signature based on the received data and the first entity's key.

Optionally the first entity includes the base key, the first entity being configured to receive, from the second entity, the bit-pattern, wherein (c) includes:

generating the variant key from the bit-pattern and the base key; and authenticating the digital signature using the generated variant key.

Optionally, the first entity storing information, wherein the data is indicative of a request to be performed on the information.

Optionally the information is a value.

Optionally the data is indicative of a read instruction.

Optionally the data is indicate of a write instruction, the data being indicative of new information to be written.

Optionally the data is indicative of a function to be applied to the information.

Optionally the function is a decrement or increment function.

Optionally the data is indicative of a value stored in the second entity.

Optionally the first entity being configured to send a request to the second entity, the data being returned in response to the request.

Optionally the data is indicative of a value stored in the second entity.

Optionally the first entity being configured to digitally sign at least some of the request with the base key.
Optionally the first entity has the base key.

Optionally the first entity storing information, wherein the data is indicative of a request to be performed on the information.

Optionally the information is a value.

Optionally the data is indicative of a read instniction.

Optionally the data is indicate of a write instruction, the data being indicative of new information to be written.
Optionally the data is indicative of a function to be applied to the information.

Optionally the function is a decrement or increment function.

Optionally the data is indicative of a value stored in the second entity.

Optionally the first entity being configured to send a read request to the second entity, the data being retumed in response to the request.

Optionally the data is indicative of a value stored in the second entity.

Optionally the first entity being configured to digitally sign at least some of the request with the base key.

Optionally there is provided a first entity, including:
a first bit-pattern a non-volatile memory storing resource data, a first base key for use with at least a first variant key;

a second variant key for use with a second base key, the second variant key being the result of a one way function applied to: the second base key; and the first bit-pattern or a modified bit-pattern based on the first bit-pattern.

Optionally there is provided a first entity configured for use in a method of enabling or disabling a verification process of a first entity in response to a predetermined event, the first entity having at least one associated bit-pattern and at least one variant key, each of the variant keys having been generated by applying a one way function to: a base key; and one or more of the at least one bit-patterns, respectively; or one or more alternative bit patterns, each of the alternative bit-patterns being based on one or the at least one bit-patterns, the method including the method including:

(a) determining that the predetermined event has happened; and (b) enabling or disabling at least one of the first variant keys in response the predetermined event.

Optionally there is provided a first entity for use in a system for enabling authenticated communication between a first entity and at least one other entity, the system including a second entity, wherein:

the first entity and the second entity share transport keys; and the second entity includes at least one authentication key configured to be transported from the second entity to the first entity using the transport keys, the authentication key being usable to enable the authenticated communication by the first entity.

Optionally there is provided a first entity configured for use in a method of storing a first bit-pattern in non-volatile memory of a device, the method comprising:

(a) applying a one way function to a second bit-pattern associated with the device, thereby to generate a first result;

(b) applying a second function to the first result and the fust bit-pattern, thereby to generate a second result;
and (c) storing the second result in the memory, thereby indirectly storing the first bit-pattern.

Optionally there is provided a first entity configured for use in a method of storing a bit-pattern in each of a plurality of devices, each of the devices having a memory, the method comprising, for each device:

(a) determining a first memory location; and (b) storing the bit-pattern at the first memory location;

wherein the first memory locations are different in at least a plurality of the respective devices.
Optionally there is provided a first entity configured for use in a method of storing at least one functionally identical code segment in each of a plurality of devices, each of the devices having a memory, the method comprising, for each device:

(a) determining a first memory location; and (b) storing a first of the at least one code segments in the memory at the first memory location;
wherein the first memory location is different in at least a plurality of the respective devices.

Optionally there is provided a first entity configured for implementing a method for providing a sequence of nonces (RO, Rl, R2, ... ) commencing with a current seed of a sequence of seeds (xl, x2, x3,...), the method comprising:

(a) applying a one-way function to the current seed, thereby to generate a current nonce; (b) outputting the current nonce;

(c) using the current seed to generate a next seed in a sequence of seeds, the seed so generated becoming the current seed; and (c) repeating steps (a) to (c) as required to generate further nonces in the sequence of nonces.

Optionally there is provided a first entity configured for implementing a method of storing multiple first bit-patterns in non-volatile memory of a device, the method comprising, for each of the first bit-patterns to be stored:
(a) applying a one way function to a third bit-pattern based on a second bit-pattem associated with the device, thereby to generate a first result;

(b) applying a second function to the first result and the first bit-pattern, thereby to generate a second result;
and (c) storing the second result in the memory, thereby indirectly storing the first bit-pattern;

wherein the third bit-pattems used for the respective first bit-pattems are relatively unique compared to each other.

In a thirty fifth aspect the present invention provides a first entity including:
a first bit-pattem a non-volatile memory storing resource data, a first base key for use with at least a first variant key;

a second variant key for use with a second base key, the second variant key being the result of a one way function applied to: the second base key; and the first bit-pattern or a modified bit-pattern based on the first bit-pattern.

Optionally the first variant key is stored in a second entity.

Optionally the second base key is stored in a third entity.

Optionally the first entity is configured to receive a request from any of a plurality of second entities, the request being indicative of at least one operation to be performed on the resource data, each of the second entities having an associated bit-pattern and one of the first variant keys, the first variant key in each of second entities being based on the result of applying a one way function to the fust base key and the associated bit-pattern of that second entity, the first entity being configured to:

(a) receive the request from one of the second entities;

(b) perform the at least one operation in the request, thereby to generate a response;

(c) use the first base key to digitally sign at least part of the response, thereby to generate a digital signature;
and (d) send the response and the digital signature to the second entity from which the request was received, such that the second entity can verify the at least part of the response using its variant key.

Optionally the first entity is configured to, prior to (b), receive the associated bit-pattern from the second entity that makes the request in (a), wherein (c) includes:

(i) using the first base key and the associated bit-pattern received from the second entity to generate the first variant key of the second entity making the request in (a); and (ii) using the first variant key generated in (i) to perform the signing of at least part of the response the response.

Optionally the first entity is configured to receive a request from any of one or more third entities, the request being indicative of at least one operation to be performed on the resource data, each of the one or more third entities having the second base key, the first entity being configured to:

(e) receive the request from the one of the third entities;

(f) perform the at least one operation in the request, thereby to generate a response;

(g) use the second variant key to digitally sign at least part of the response, thereby to generate a digital signature; and (h) send the response and the digital signature to the third entity from which the request was received, such that the third entity can verify the at least part of the response using its base key.

Optionally the first entity is configured to send the first bit-pattern to the third entity that makes the request in (e), such that the third entity can:

(i) use the second base key and the bit-pattern received from the first entity to generate the second variant key; and (ii) use the second variant key generated in (i) to perform the verification.

Optionally the first entity is configured to receive a request from any of one or more third entities, the request being indicative of at least one operation to be performed on the resource data, each of the one or more third entities having the second base key, the fust entity being configured to:

(a) receive the request from the one of the third entities;

(b) perform the at least one operation in the request, thereby to generate a response;

(c) use the first variant key to digitally sign at least part of at least the response, thereby to generate a digital signature; and (d) send the response and the digital signature to the third entity from which the request was received, such that the third entity can verify at least part of the response using its base key.

Optionally the first entity is configured to send the first bit-pattern the third entity that makes the request in (a), such that the third entity can:

(i) use the second base key and the bit-pattern received from the first entity to generate the second variant key; and (ii) use the second variant key generated in (i) to perform the verification.

Optionally the second and third entities have different permissions in relation to the operations they can perform on the resource data, the permissions being defined based which of the first and second base key and variant key combinations is used for the verification.

Optionally the first base and variant key combination provides a higher permission to perform an operation on the resource data than the second base key and variant key combination.

Optionally the second and third entities have different pemiissions in relation to the operations they can perform on the resource data, the permissions being defined based which of the first and second base key and variant key combinations is used for the verification.

Optionally the first base and variant key combination provides a higher permission to perform an operation on the resource data than the second base key and variant key combination.

Optionally the first entity is configured to receive a request from any of a plurality of second entities, the request being indicative of at least one operation to be performed on the resource data, each of the second entities having an associated bit-pattern and one of the first variant keys, the first variant key in each of second entities being based on the result of applying a one way function to the fust base key and the associated bit-pattern of that second entity, the first entity being configured to:

(a) receive the request from one of the second entities;

(b) receive the bit-pattern associated with the entity from which the request was received;

(c) receive a digital signature from the entity from which the request was received, the digital signature having been generated by digitally signing at least part of the request using the variant key;

(d) generate the variant key of the entity from which the request sent, by applying the one way function to the first base key and the received bit pattem; and (e) verify the request by digitally signing at least part of the request using the variant key generated in (d) and comparing the produced signature against the signature received in (d).

Optionally the first entity is configured to receive a request from any of one or more third entities, the request being indicative of at least one operation to be performed on the resource data, each of the one or more third entities having the second base key, the first entity being configured to:

(f) receive the request from the one of the third entities;

(g) receive a digital signature from the third entity from which the request was received, the digital signature having been generated by the third entity signing at least part of the request using the second variant key;

(h) verify the at least part of the request by digitally signing at least part of the request using the second variant key and comparing the produced signature against the signature received in (g).

Optionally the first entity is configured to send the first bit-pattern to the third entity that makes the request in (f) , such that the third entity can:

(i) use the second base key and the bit-pattern received from the first entity to generate the second variant key; and (ii) use the second variant key generated in (i) to digitally sign at least part of the request; and (iii) send the request for receipt by the first entity in (a).

Optionally the first entity is configured to receive a request from any of one or more third entities, the request being indicative of at least one operation to be performed on the resource data, each of the one or more third entities having the second base key, the first entity being configured to:

(f) receive the request from the one of the third entities;

(g) receive a digital signature from the third entity from which the request was received, the digital signature having been generated by the third entity signing at least part of the request using the second variant key;

(h) verify the at least part of the request by digitally signing at least part of the request using the second variant key and comparing the produced signature against the signature received in (g).

Optionally the second and third entities have different permissions in relation to the operations they can perform on the resource data, the permissions being defined based which of the first and second base key and variant key combinations is used for the verification.

Optionally the first base and variant key combination provides a higher permission to perform an operation on the resource data than the second base key and variant key combination.

Optionally the resource data represents a physical property.

Optionally the physical property is a remaining amount of a physical resource.
Optionally the resource is a consumable resource.

Optionally the resource entity is physically attached to a reservoir or magazine that holds the consumable resource.

Optionally the resource is a fluid.

Optionally the fluid is ink.

Optionally the operation includes a read, in which the resource data is read by the entity making the request.

Optionally the operation includes write, in which the resource data is modified by the entity making the request.
Optionally the operation includes decrementing, in which the resource is decremented by the entity making the request.

Optionally the one way function is a hash function.
Optionally the one way function is SHAI.

Optionally a second entity configured for use with the first entity including:
a first bit-pattern a non-volatile memory storing resource data, a first base key for use with at least a first variant key;

a second variant key for use with a second base key, the second variant key being the result of a one way function applied to: the second base key; and the first bit-pattern or a modified bit-pattern based on the first bit-pattern.

Optionally a second entity configured for use with the first entity configured to receive a request from any of a plurality of second entities, the request being indicative of at least one operation to be performed on the resource data, each of the second entities having an associated bit-pattern and one of the first variant keys, the fust variant key in each of second entities being based on the result of applying a one way function to the fust base key and the associated bit-pattem of that second entity, the first entity being configured to:

(a) receive the request from one of the second entities;

(b) perform the at least one operation in the request, thereby to generate a response;

(c) use the first base key to digitally sign at least part of the response, thereby to generate a digital signature;
and (d) send the response and the digital signature to the second entity from which the request was received, such that the second entity can verify the at least part of the response using its variant key.

Optionally a second entity configured for use with the first entity configured to receive a request from any of a plurality of second entities, the request being indicative of at least one operation to be performed on the resource data, each of the second entities having an associated bit-pattern and one of the first variant keys, the first variant key in each of second entities being based on the result of applying a one way function to the first base key and the associated bit-pattern of that second entity, the first entity being configured to:

(a) receive the request from one of the second entities;

(b) receive the bit-pattern associated with the entity from which the request was received;

(c) receive a digital signature from the entity from which the request was received, the digital signature having been generated by digitally signing at least part of the request using the variant key;

(d) generate the variant key of the entity from which the request sent, by applying the one way function to the first base key and the received bit pattern; and (e) verify the request by digitally signing at least part of the request using the variant key generated in (d) and comparing the produced signature against the signature received in (d).

Optionally a third entity configured for use with the first entity configured to receive a request from any of one or more third entities, the request being indicative of at least one operation to be performed on the resource data, each of the one or more third entities having the second base key, the first entity being configured to:

(e) receive the request from the one of the third entities;

(f) perform the at least one operation in the request, thereby to generate a response;

(g) use the second variant key to digitally sign at least part of the response, thereby to generate a digital signature; and (h) send the response and the digital signature to the third entity from which the request was received, such that the third entity can verify the at least part of the response using its base key.

Optionally a third entity configured for use with the first entity configured to receive a request from any of one or more third entities, the request being indicative of at least one operation to be performed on the resource data, each of the one or more third entities having the second base key, the first entity being configured to:

(a) receive the request from the one of the third entities;

(b) perform the at least one operation in the request, thereby to generate a response;

(c) use the first variant key to digitally sign at least part of at least the response, thereby to generate a digital signature; and (d) send the response and the digital signature to the third entity from which the request was received, such that the third entity can verify at least part of the response using its base key.

Optionally a third entity configured for use with the first entity configured to receive a request from any of one or more third entities, the request being indicative of at least one operation to be performed on the resource data, each of the one or more third entities having the second base key, the fust entity being configured to:
(f) receive the request from the one of the third entities;

(g) receive a digital signature from the third entity from which the request was received, the digital signature having been generated by the third entity signing at least part of the request using the second variant key;

(h) verify the at least part of the request by digitally signing at least part of the request using the second variant key and comparing the produced signature against the signature received in (g).

Optionally there is provided a first entity configured to authenticate a digital signature supplied by a second entity, wherein one of the entities includes a base key and the other of the entities includes a variant key and a bit-pattern, the variant key being based on the result of applying a one way function to the base key and the bit-pattern, the digital signature having been generated by the second entity using its key to digitally signing at least part of data to be authenticated, the first entity being configured to:

(a) receive the digital signature from the second entity;

(b) receive the data; and (c) authenticate the digital signature based on the received data and the first entity's key.

Optionally there is provided a first entity configured to implement a method of enabling or disabling a verification process of a first entity in response to a predetermined event, the first entity having at least one associated bit-pattem and at least one variant key, each of the variant keys having been generated by applying a one way function to: a base key; and one or more of the at least one bit-patterns, respectively; or one or more alternative bit pattems, each of the alternative bit-patterns being based on one or the at least one bit-patterns, the method including the method including:

(a) determining that the predetermined event has happened; and (b) enabling or disabling at least one of the first variant keys in response the predetermined event.

Optionally there is provided a first entity configured for usein a system for enabling authenticated communication between a first entity and at least one other entity, the system including a second entity, wherein:

the first entity and the second entity share transport keys; and the second entity includes at least one authentication key configured to be transported from the second entity to the first entity using the transport keys, the authentication key being usable to enable the authenticated communication by the first entity.

Optionally there is provided a first entity configured to implement a method of storing a first bit-pattem in non-volatile memory of a device, the method comprising:

(a) applying a one way function to a second bit-pattern associated with the device, thereby to generate a first result;

(b) applying a second function to the first result and the first bit-pattern, thereby to generate a second result;
and (c) storing the second result in the memory, thereby indirectly storing the first bit-pattern.

Optionally there is provided a first entity configured to implement a method of storing a bit-pattern in each of a plurality of devices, each of the devices having a memory, the method comprising, for each device:

(a) determining a first memory location; and (b) storing the bit-pattern at the first memory location;

wherein the first memory locations are different in at least a plurality of the respective devices.

Optionally there is provided a first entity configured to implement a method of storing at least one functionally identical code segment in each of a plurality of devices, each of the devices having a memory, the method comprising, for each device:

(a) determining a first memory location; and (b) storing a first of the at least one code segments in the memory at the first memory location;
wherein the first memory location is different in at least a plurality of the respective devices.
Optionally there is provided a first entity configured to implement a method for providing a sequence of nonces (RO, Rl, R2, ... ) commencing with a current seed of a sequence of seeds (xl, x2, x3,...), the method comprising:

(a) applying a one-way function to the current seed, thereby to generate a current nonce; (b) outputting the current nonce;

(c) using the current seed to generate a next seed in a sequence of seeds, the seed so generated becoming the current seed; and (c) repeating steps (a) to (c) as required to generate further nonces in the sequence of nonces.

Optionally there is provided a first entity configured to implement a method of storing multiple first bit-patterns in non-volatile memory of a device, the method comprising, for each of the first bit-patterns to be stored:

(a) applying a one way function to a third bit-pattern based on a second bit-pattern associated with the device, thereby to generate a first result;

(b) applying a second function to the first result and the fust bit-pattern, thereby to generate a second result;
and (c) storing the second result in the memory, thereby indirectly storing the first bit-pattern;

wherein the third bit-patterns used for the respective first bit-patterns are relatively unique coinpared to each other.

In a thirty sixth aspect the present invention provides a method of enabling or disabling a verification process of a first entity in response to a predetermined event, the first entity having at least one associated bit-pattern and at least one variant key, each of the variant keys having been generated by applying a one way function to: a base key; and one or more of the at least one bit-patterns, respectively; or one or more alternative bit patterns, each of the alternative bit-patterns being based on one or the at least one bit-patterns, the method including the method including:

(a) determining that the predetermined event has happened; and (b) enabling or disabling at least one of the first variant keys in response the predetermined event.

Optionally step (a) includes disabling at least one of the variant keys, such that the disabled at least one variant key can no longer be used to digitally sign information in that enti .

Optionally step (a) includes disabling at least one of the variant keys, such that the disabled at least one variant key can no longer be used to verify information signed by one or more respective base keys related to the disabled at least one variant key in that entity.

Optionally the step of disabling the at least one variant key includes modifying a status of a flag associated with that at least one variant key.

Optionally the step of disabling the at least one variant key includes deleting that at least one variant key.
Optionally the step of disabling the at least one variant key includes modifying that at least one variant key Optionally the event is a predetermined point in time being reached or passed.

Optionally the first entity includes a plurality of the variant keys, the plurality of variant keys being based on the result of a one way function applied to: a respective one of a corresponding plurality of base keys; and one of the at least one bit-patterns or one of the at least one alternative bit-patterns, the method including the steps of:

determining that a predetermined event related to one of the variant keys has happened; and enabling or disabling at least one of the plurality of variant keys with which the predetermined event is associated.
Optionally the plurality of base keys has a corresponding sequence of predetermined events associated with them, the method including the steps of:

(a) detennining that one of the predetermined event has happened; and (b) enabling or disabling the variant key in the sequence corresponding to predetermined event that is determined to have happened.

Optionally the variant keys are disabled in the order of the sequence of predetermined events.

Optionally the sequence of events is chronological.
Optionally each of the events includes a time being reached.

Optionally the step of determining that one of the events has happened includes receiving a time from a trusted source.

Optionally the time is a date.

Optionally the date is determined with a resolution of a month.

Optionally the predetermined event includes detection of compromise of one or more of the keys, the method including disabling the one or more variant keys corresponding to the one or more keys that were compromised.

Optionally the predetermined event includes suspect compromise of one or more of the keys, the method including disabling the one or more variant keys corresponding to the one or more keys that were suspected of being compromised.

In a further aspect the present invention provides a method of manufacturing second entities for use in the verification process with the first entity of claim 1, each of the first entities including at least first and second variant key, the first variant key having been generated by applying a one way function to a fust base key and a first bit-pattern, and the second variant key having been generated by applying a one way function to a second base key and a second bit-pattern, the method comprising the steps of:

manufacturing a plurality of second entities for use with the first entities, each of the second entities including at least the first base key; and upon the first variant key being disabled in response to one of the predetermined event, manufacturing a plurality of third entities for use with the first entities, each of the third entities including at least the second base key.

Optionally the first variarit key is automatically disabled in response to a predetermined event.
Optionally the method further includes the step of causing the first variant key to be disabled.
Optionally the first variant key is disabled in response to a time being reached.

Optionally at least some of the first entities have one or more further variant keys, each of the respective further variant keys having been generated by applying a one way function to respective further base keys and bit-patterns, each of the variant keys being enabled or disabled in response to respective predetermined events, the method comprising the step of manufacturing a sequence of sets of second entities, each set of the second entities being manufactured such that the variant key corresponding to its base key is enabled for the verification process during the life of that set.

Optionally the predetermined events are selected such that the variant keys corresponding with the base keys of more than one of the sets are enabled at once.

Optionally there is provided a method using a first entity configured to authenticate a digital signature supplied by a second entity, wherein one of the entities includes a base key and the other of the entities includes a variant key and a bit-pattern, the variant key being based on the result of applying a one way function to the base key and the bit-pattern, the digital signature having been generated by the second entity using its key to digitally signing at least part of data to be authenticated, the first entity being confrgured to:
(a) receive the digital signature from the second entity;

(b) receive the data; and (c) authenticate the digital signature based on the received data and the first entity's key.

Optionally there is provided a method using a first entity including:
a first bit-pattern a non-volatile memory storing resource data, a fust base key for use with at least a first variant key;

a second variant key for use with a second base key, the second variant key being the result of a one way function applied to: the second base key; and the first bit-pattem or a modified bit-pattern based on the first bit-pattem.

Optionally there is provided a method using a system for enabling authenticated communication between a first entity and at least one other entity, the system including a second entity, wherein:

the first entity and the second entity share transport keys; and the second entity includes at least one authentication key configured to be transported from the second entity to the first entity using the transport keys, the authentication key being usable to enable the authenticated communication by the first entity.

Optionally there is provided a method including storing a first bit-pattern in non-volatile memory of a device, the method comprising:

(a) applying a one way function to a second bit-pattern associated with the device, thereby to generate a first result;

(b) applying a second function to the first result and the first bit-pattern, thereby to generate a second result;
and (c) storing the second result in the memory, thereby indirectly storing the first bit-pattern.

Optionally there is provided a method including storing a bit-pattem in each of a plurality of devices, each of the devices having a memory, the method comprising, for each device:

(a) deternuning a first memory location; and (b) storing the bit-pattern at the first memory location;

wherein the first memory locations are different in at least a plurality of the respective devices.
Optionally there is provided a method including storing at least one functionally identical code segment in each of a plurality of devices, each of the devices having a memory, the method comprising, for each device:

(a) determining a first memory location; and (b) storing a first of the at least one code segments in the memory at the first memory location;
wherein the first memory location is different in at least a plurality of the respective devices.
Optionally there is provided a method including providing a sequence of nonces (RO, Rl, R2, ... ) commencing with a current seed of a sequence of seeds (xl, x2, x3,...), the method comprising:

(a) applying a one-way function to the current seed, thereby to generate a current nonce; (b) outputting the current nonce;

(c) using the current seed to generate a next seed in a sequence of seeds, the seed so generated becoming the current seed; and (c) repeating steps (a) to (c) as required to generate further nonces in the sequence of nonces.

Optionally there is provided a method including storing multiple first bit-patterns in non-volatile memory of a device, the method comprising, for each of the first bit-patterns to be stored:

(a) applying a one way function to a third bit-pattern based on a second bit-pattern associated with the device, thereby to generate a first result;

(b) applying a second function to the first result and the first bit-pattem, thereby to generate a second result;
and (c) storing the second result in the memory, thereby indirectly storing the first bit-pattern;

wherein the third bit-patterns used for the respective first bit-patterns are relatively unique compared to each other.

In a thirty seventh aspect the present invention provides a system for enabling authenticated communication between a first entity and at least one other entity, the system including a second entity, wherein:

the first entity and the second entity share transport keys; and the second entity includes at least one authentication key configured to be transported from the second entity to the first entity using the transport keys, the authentication key being usable to enable the authenticated communication by the first entity.

Optionally the transport keys include:

a first transport key in the first entity; and a second transport key in the second entity.
Optionally the first and second transport keys are the same.

Optionally the second transport key is a base key and the first transport key is a variant key, the variant key having been generated by applying a one way function to the base key and a first bit-pattern.

Optionally the first bit-pattern is stored in the first entity.

Optionally each of the first and second transport keys is a second bit-pattern stored in the first and second entities during manufacture of the system or its components.

Optionally the second bit-pattern was determined randomly or pseudo-randomly.

Optionally the second bit-pattern was generated using a stochastic process or mechanism.

Optionally the authentication key enables authenticated communication between the first and second entities.

Optionally the authentication key provides the first entity with permission to request performance of at least one operation on at least one value in the second entity.

Optionally the authentication key enables authenticated communication between the first entity and one or more entities other than the second entity.

Optionally the authentication key is a variant key.

Optionally the one or more entities include the base key corresponding to the authentication key.

Optionally the variant key in each system is relatively unique compared to the variant keys in the other systems.
Optionally the authentication key is a third bit-pattern that was determined randomly or pseudo-randomly.
Optionally the third bit-pattern was generated using a stochastic process or mechanism.

In a further aspect the present invention provides a system for enabling authenticated communication between a first entity and at least one other entity, the system including a second entity, wherein:

the first entity and the second entity share additional transport keys;

the second entity and each of the at least one other entities share transport keys; and the second entity includes at least one authentication key configured to be transported from the second entity to the first entity using the fust transport keys and to each of the at least one other entities using the respective additional shared transport keys, such that the authentication keys, once transported to the first and at least one other entities, enable verified communication therebetween.

Optinally each pair of transport keys is different from the other pairs of transport keys.

Optionally the authentication key is the first transport key.

Optionally the authentication key is the additional transport key for one of the at least one other entities.
Optionally the authentication key is not the same as any of the transport keys.

Optionally the authentication key is a variant key, the variant key having been generated by applying a one way function to a base key and a first bit-pattern.

Optionally the first transport key is a bit-pattem stored in the first and second entities during manufacture of the system or its components.

Optionally the bit-pattern was detemiined randomly or pseudo-randomly.
Optionally the bit-pattern was generated using a stochastic process or mechanism.

In a further aspect the present invention provides a method of manufacturing a system having at least first and second entities, method comprising the steps of:

providing the first and second entities with transport keys; and providing the second entity with at least one authentication key;

the system being configured to enable transport of the at least one authentication key from the second entity to the first entity using the transport keys, the authentication key being usable to enable the authenticated communication by the first entity.
Optionally the transport keys include:

a first transport key in the first entity; and a second transport key in the second entity.

Optionally the first and second transport keys are the same.

Optionally the second transport key is a base key and the first transport key is a variant key, the variant key having been generated by applying a one way function to the base key and a first bit-pattern.

Optionally the first bit-pattern is stored in the first entity.

Optionally each of the first and second transport keys is a second bit-pattern stored in the first and second entities during manufacture of the system or its components.

Optionally the second bit-pattern was determined randomly or pseudo-randomly.
Optionally the second bit-pattem was generated using a stochastic process or mechanism.

Optionally the authentication key enables authenticated communication between the first and second entities.
Optionally the authentication key enables authenticated communication between the first entity and one or more entities other than the second entity.

Optionally the authentication key is a third bit-pattern that was determined randomly or pseudo-randomly.
Optionally the third bit-pattern was generated using a stochastic process or mechanism.

In a further aspect the present invention provides a method for enabling authenticated communication between a first entity and at least one other entity in a system including a second entity, wherein:

the first entity and the second entity share first transport keys;

the second entity and each of the at least one other entities share additional transport keys; and the second entity includes at least one authentication key;

the method including the steps of:

transporting the authentication key from the second entity to the first entity using the first transport keys, and to each of the at least one other entities using the respective shared additional transport keys, such that the authentication keys, once transported to the first and at least one other entities, enable verified communication therebetween.

Optionally each pair of transport keys is different from the other pairs of transport keys.
Optionally the authentication key is the first transport key.

Optionally the authentication key is one of the additional transport keys.
Optionally the authentication key is not the same as any of the transport keys.

Optionally the authentication key is a variant key, the variant key having been generated by applyirig a one way function to a base key and a first bit-pattern.

Optionally the first transport key is a bit-pattern stored in the first and second entities during manufacture of the system or its components.

Optionally bit-pattem was determined randomly or pseudo-randomly.

Optionally the bit-pattern was generated using a stochastic process or mechanism.

Optionally there is provided a method including a fust entity configured to authenticate a digital signature supplied by a second entity, wherein one of the entities includes a base key and the other of the entities includes a variant key and a bit-pattem, the variant key being based on the result of applying a one way function to the base key and the bit-pattern, the digital signature having been generated by the second entity using its key to digitally signing at least part of data to be authenticated, the first entity being configured to:

(a) receive the digital signature from the second entity;

(b) receive the data; and (c) authenticate the digital signature based on the received data and the first entity's key.
Optionally there is provided a system including a first entity including:

a first bit-pattern a non-volatile memory storing resource data, a first base key for use with at least a first variant key;

a second variant key for use with a second base key, the second variant key being the result of a one way function applied to: the second base key; and the fust bit-pattern or a modified bit-pattern based on the first bit-pattern.

Optionally there is provided a system configured to implement a method of enabling or disabling a verification process of a first entity in response to a predetermined event, the first entity having at least one associated bit-pattern and at least one variant key, each of the variant keys having been generated by applying a one way function to: a base key; and one or more of the at least one bit-patterns, respectively; or one or more alternative bit patterns, each of the alternative bit-patterns being based on one or the at least one bit-patterns, the method including the method including:

(a) determining that the predetermined event has happened; and (b) enabling or disabling at least one of the first variant keys in response the predetermined event.
Optionally there is provided a system configured to implement a method of storing a first bit-pattern in non-volatile memory of a device, the method comprising:

(a) applying a one way function to a second bit-pattern associated with the device, thereby to generate a first result;

(b) applying a second function to the first result and the fust bit-pattern, thereby to generate a second result;
and (c) storing the second result in the memory, thereby indirectly storing the first bit-pattern.

Optionally there is provided a system configured to implement a method of storing a bit-pattern in each of a plurality of devices, each of the devices having a memory, the method comprising, for each device:

(a) determining a first memory location; and (b) storing the bit-pattern at the first memory location;

wherein the first memory locations are different in at least a plurality of the respective devices.
Optionally there is provided a system configured to implement a method of storing at least one functionally identical code segment in each of a plurality of devices, each of the devices having a memory, the method comprising, for each device:

(a) determining a first memory location; and (b) storing a first of the at least one code segments in the memory at the first memory location;
wherein the first memory location is different in at least a plurality of the respective devices.
Optionally there is provided a system configured to implement a method of providing a sequence of nonces (RO, Rl, R2, ... ) commencing with a current seed of a sequence of seeds (xl, x2, x3,...), the method comprising:

(a) applying a one-way function to the current seed, thereby to generate a current nonce; (b) outputting the current nonce;

(c) using the current seed to generate a next seed in a sequence of seeds, the seed so generated becoming the current seed; and (c) repeating steps (a) to (c) as required to generate further nonces in the sequence of nonces.

Optionally there is provided a system configured to implement a method of storing multiple first bit-patterns in non-volatile memory of a device, the method comprising, for each of the first bit-patterns to be stored:

(a) applying a one way function to a third bit-pattern based on a second bit-pattern associated with the device, thereby to generate a first result;

(b) applying a second function to the first result and the first bit-pattern, thereby to generate a second result;
and (c) storing the second result in the memory, thereby indirectly storing the first bit-pattern;

wherein the third bit-patterns used for the respective first bit-patterns are relatively unique compared to each other.

In a thirty eighth aspect the present invention provides a method of storing a first bit-pattern in non-volatile memory of a device, the method comprising:

(a) applying a one way function to a second bit-pattern associated with the device, thereby to generate a first result;

(b) applying a second function to the first result and the first bit-pattern, thereby to generate a second result;
and (c) storing the second result in the memory, thereby indirectly storing the first bit-pattern.
Optionally the one way function is more cryptographically secure than the second function.
Optionally the second function is a logical function.

Optionally the logical function is an XOR function.

Optionally the one way function is a hash function.
Optionally the one way function is SHA1.

Optionally the first bit-pattern is a key.

Optionally the method further includes the step of storing one or more code segments in the memory, the code segments being configured to run on a processor of the device, thereby enabling the device to:

apply the one way function to the second bit-pattern, thereby to generate the first result;

apply a third function to the first result and the second result, thereby to generate the first bit-pattern;
wherein the third function is the inverse of the second function.

Optionally the third function and the second function are the same.

Optionally the second bit-pattern was generated randonily or pseudo-randomly.

Optionally the method further includes the step, performed prior to step (a), of determining the second bit-pattern.
Optionally determining the second bit-pattern includes generating the second bit-pattern randomly or pseudo-randomly.

Optionally detem-ining the second bit-pattern includes generating the second bit-pattern based on a stochastic process or mechanism.

Optionally determining the second bit-pattern includes selecting the second-bit pattern from an existing list or sequence of second bit-patterns.

In a further aspect the present invention provides method of storing a first bit-pattecn in non-volatile memory of each of a plurality of devices, the method comprising, for each of the devices:

(a) applying a one way function to a second bit-pattern associated with the device, thereby to generate a first result;

(b) applying a second function to the first result and the first bit-pattern, thereby to generate a second result;
and (c) storing the second result in the non-volatile memory, thereby indirectly storing the first bit-pattern;
wherein the second bit-pattems of the respective devices are relatively unique with respect to each other.
Optionally the one way function is more cryptographically secure than the second function.

Optionally the second function is a logical function.
Optionally the logical function is an XOR function.
Optionally the one way function is a hash function.

Optionally the one way function is SHA1.

Optionally the first bit-pattern is a key.

Optionally step (c) comprises, for each device:
(d) determining a first memory location; and (e) storing the second result at the first memory location;

wherein the first memory locations are different in at least a plurality of the respective devices.

Optionally step (d) includes randomly selecting the first memory location.

Optionally step (a) includes selecting the first memory location based on a stochastic process or mechanism.
Optionally step (a) includes selecting the first memory location from an existing list or sequence of memory locations.

Optionally the method further includes the step of storing one or more code segments in the device, the code segments being configured to run on a processor of the device, thereby enabling the device to:

apply the one way function to the second bit-pattern, thereby to generate the first result; and apply a third function to the first result and the second result, thereby to generate the first bit-pattern;
wherein the third function is the inverse of the second function.

Optionally the third function and the second function are the same.

Optionally the second bit-patterns have characteristics associated with random numbers.
Optionally the second bit-pattern was generated randomly or pseudo-randomly.

Optionally the method further includes the step, performed prior to step (a), of determining the second bit-pattern.
Optionally determining the second bit-pattern includes generating the second bit-pattern randomly or pseudo-randomly.

Optionally determining the second bit-pattern includes generating the second bit-pattern based on a stochastic process or mechanism.

Optionally there is provided a device manufactured in accordance with the method of storing a first bit-pattern in non-volatile memory of a device, the method comprising:

(a) applying a one way function to a second bit-pattern associated with the device, thereby to generate a first result;

(b) applying a second function to the first result and the first bit-pattern, thereby to generate a second result;
and (c) storing the second result in the memory, thereby indirectly storing the first bit-pattern.

Optionally there is provided a device manufactured in accordance with the method including the step of storing one or more code segments in the memory, the code segments being configured to run on a processor of the device, thereby enabling the device to:

apply the one way function to the second bit-pattern, thereby to generate the first result;

apply a third function to the first result and the second result, thereby to generate the first bit-pattern;
wherein the third function is the inverse of the second function.

Optionally there is provided a device manufactured in accordance with the method of storing a first bit-pattern in non-volatile memory of each of a plurality of devices, the method comprising, for each of the devices:

(a) applying a one way function to a second bit-pattern associated with the device, thereby to generate a first result;

(b) applying a second function to the first result and the first bit-pattern, thereby to generate a second result;
and (c) storing the second result in the non-volatile memory, thereby indirectly storing the first bit-pattem;
wherein the second bit-patterns of the respective devices are relatively unique with respect to each other.
Optionally there is provided a device manufactured in accordance with the method including the step of storing one or more code segments in the device, the code segments being configured to run on a processor of the device, thereby enabling the device to:

apply the one way function to the second bit-pattern, thereby to generate the first result; and apply a third function to the first result and the second result, thereby to generate the first bit-pattern;
wherein the third function is the inverse of the second function.

Optionally the device having an associated second bit-pattern, and non-volatile memory, the non-volatile memory indirectly storing a first bit-pattern in the form of a second result, the second result being generated by:

(a) applying a one way function to the second bit-pattern, thereby to generate a first result; and (b) applying a second function to the first result and the first bit-pattern, thereby to generate the second result.

Optionally the device further includes a processor, the processor being configured to run one or more code segments that:

(c) apply the one way function to the second bit pattern, thereby to generate the first result; and (d) apply a third function to the first result and the second result, the third function being the inverse of the second function, thereby to generate the first bit-pattern.

Optionally the third function and the second function are the same.

Optionally the one or more code segments, when run on the processor, use the first bit-pattern in a cryptographic process.

Optionally the cryptographic process is digital signing.

Optionally the one way function is more cryptographically secure than the second function.

Optionally the second function is a logical function.

Optionally the logical function is an XOR function.
Optionally the one way function is a hash function.
Optionally the one way function is SHA1.

Optionally the first bit-pattern is a key.

Optionally the second bit-pattern was generated randomly or pseudo-randomly.

Optionally the second bit-pattem was generated using a stochastic process or mechanism.

Optionally there is provided a method implemented in a first entity configured to authenticate a digital signature supplied by a second entity, wherein one of the entities includes a base key and the other of the entities includes a variant key and a bit-pattern, the variant key being based on the result of applying a one way function to the base key and the bit-pattern, the digital signature having been generated by the second entity using its key to digitally signing at least part of data to be authenticated, the first entity being configured to:

(a) receive the digital signature from the second entity;
(b) receive the data; and (c) authenticate the digital signature based on the received data and the first entity's key.
Optionally there is provided a method implemented in a first entity including:

a fust bit-pattern a non-volatile memory storing resource data, a first base key for use with at least a first variant key;

a second variant key for use with a second base key, the second variant key being the result of a one way function applied to: the second base key; and the first bit-pattern or a modified bit-pattern based on the first bit-pattern.

Optionally there is provided a method for enabling or disabling a verification process of a first entity in response to a predetermined event, the first entity having at least one associated bit-pattern and at least one variant key, each of the variant keys having been generated by applying a one way function to: a base key; and one or more of the at least one bit-patterns, respectively; or one or more alternative bit pattems, each of the alternative bit-patterns being based on one or the at least one bit-patterns, the method including the method including:

(a) determining that the predetermined event has happened; and (b) enabling or disabling at least one of the first variant keys in response the predetermined event.

Optionally there is provided a method implemented in a system for enabling authenticated communication between a first entity and at least one other entity, the system including a second entity, wherein:

the first entity and the second entity share transport keys; and the second entity includes at least one authentication key configured to be transported from the second entity to the first entity using the transport keys, the authentication key being usable to enable the authenticated communication by the first entity.

Optionally there is provided a method for storing a bit-pattern in each of a plurality of devices, each of the devices having a memory, the method comprising, for each device:

(a) determining a first memory location; and (b) storing the bit-pattetn at the first memory location;

wherein the first memory locations are different in at least a plurality of the respective devices.

Optionally there is provided a method for storing at least one functionally identical code segment in each of a plurality of devices, each of the devices having a memory, the method comprising, for each device:

(a) determining a first memory location; and (b) storing a first of the at least one code segments in the memoty at the first memory location;
wherein the first memory location is different in at least a plurality of the respective devices.

Optionally there is provided a method for providing a sequence of nonces (RO, Rl, R2, ... ) commencing with a current seed of a sequence of seeds (xl, x2, x3,...), the method comprising:

(a) applying a one-way function to the current seed, thereby to generate a current nonce; (b) outputting the current nonce;

(c) using the current seed to generate a next seed in a sequence of seeds, the seed so generated becoming the current seed; and (c) repeating steps (a) to (c) as required to generate further nonces in the sequence of nonces.

Optionally there is provided a method for storing multiple first bit-patterns in non-volatile memory of a device, the method comprising, for each of the first bit-patterns to be stored:

(a) applying a one way function to a third bit-pattern based on a second bit-pattern associated with the device, thereby to generate a first result;

(b) applying a second function to the first result and the first bit-pattern, thereby to generate a second result;
and (c) storing the second result in the memory, thereby indirectly storing the first bit-pattern;

wherein the third bit-patterns used for the respective first bit-patterns are relatively unique compared to each other.

In a thirty ninth aspect the present invention provides a method of storing a bit-pattern in each of a plurality of devices, each of the devices having a memory, the method comprising, for each device:

(a) determining a first memory location; and (b) storing the bit-pattern at the first memory location;

wherein the first memory locations are different in at least a plurality of the respective devices.
Optionally step (a) includes randomly selecting the first memory location.

Optionally step (a) includes selecting the first memory location based on a stochastic process or mechanism.
Optionally step (a) includes selecting the first memory location from an existing list or sequence of memory locations.

Optionally the memory is non-volatile memory.

Optionally, the method further comprises storing one or more code segments in the memory of each device, the one or more code segments including data indicative of the first memory location at which the bit-pattern is stored on that device.

Optionally, wherein the first memory locations of the devices are selected such that, from device to device, there is no overlap of the positions of at least some of the bits, bytes or characters of the devices' respective bit-pattern.
Optionally the first memory locations of the devices are selected such that, from device to device, positions of at least some of the bits, bytes or characters of the devices' respective bit-patterns overlap.

Optionally the first memory locations of the devices are selected such that, from device to device, bit, byte or character positions of the devices' respective bit-patterns are shuffled, rotated or otherwise ordered differently.

Optionally the first memory locations of the devices are selected such that, from device to device, bit, byte or character positions of the devices' respective bit-patterns are shuffled, rotated or otherwise ordered differently.
Optionally the method further comprises:

applying a function to the first bit pattern and a second bit pattem, thereby to generate a result; and storing the result in the first memory location, thereby indirectly storing the first bit-pattecn.
Optionally the second bit-pattern is stored with the device.

Optionally the second bit-pattern is stored in the device in a non-volatile manner.

Optionally the function is a logical function.

Optionally the logical function is an XOR function.
Optionally the first bit-pattein is a key.

Optionally the second bit pattern was generated randomly.

Optionally the method further comprises randomly selecting the second bit-pattem.

Optionally the method further comprises selecting the second bit-pattern based on a stochastic process or mechanism.

Optionally the method further comprises selecting the second bit-pattern from an existing list or sequence of bit-pattems.

Optionally the first memory locations of the devices are selected such that, from device to device, there is no overlap of the positions of at least some of the bits, bytes or characters of the devices' respective results.
Optionally the first memory locations of the devices are selected such that, from device to device, positions of at least some of the bits, bytes or characters of the devices' respective results overlap.

Optionally the first memory locations of the devices are selected such that, from device to device, bit, byte or character positions of the devices' respective results are shuffled, rotated or otherwise ordered differently.
Optionally the first memory locations of the devices are selected such that, from device to device, bit, byte or character positions of the devices' respective results are shuffled, rotated or otherwise ordered differently.

Optionally the respective second bit-patterns are stored at a second memory location of each of the respective devices, wherein the second memory locations are different in at least a plurality of the respective devices.

Optionally the second memory locations of the devices are selected such that, from device to device, there is no overlap of the positions of at least some of the bits, bytes or characters of the devices' respective second bit-patterns.

Optionally the second memory locations of the devices are selected such that, from device to device, positions of at least some of the bits, bytes or characters of the devices' respective second bit-patterns overlap.

Optionally the second memory locations of the devices are selected such that, from device to device, bit, byte or character positions of the devices' respective second bit-patterns are shuffled, rotated or otherwise ordered differently.

Optionally the second memory locations of the devices are selected such that, from device to device, bit, byte or character positions of the devices' respectives second bit-patterns are shuffled, rotated or otherwise ordered differently.

Optionally the method further comprises storing one or more code segments in the memory of each device, the one or more code segments including data indicative of the second memory location at which the second bit-pattem is stored on that device.

Optionally the method further comprises for each device:
determining a second memory location; and storing, at the second memory location, a result of applying a function to the bit-pattern;

wherein the second memory locations are different in at least a plurality of the respective devices.
Optionally the function is a logical operation.

Optionally the function is a bit inversion operation.

Optionally step (a) includes randomly selecting the second memory location.

Optionally step (a) includes selecting the second memory location based on a stochastic process or mechanism.
Optionally step (a) includes selecting the second memory location from an existing list or sequence of memory locations.

Optionally the memory is non-volatile memory.

Optionally the method further comprises storing one or more code segments in the memory of each device, the one or more code segments including data indicative of the second memory location at which the result is stored on that device.

Optionally the second memory locations of the devices are selected such that, from device to device, there is no overlap of the positions of at least some of the bits, bytes or characters of the devices' respective results.
Optionally the second memory locations of the devices are selected such that, from device to device, positions of at least some of the bits, bytes or characters of the devices' respective results overlap.

Optionally the second memory locations of the devices are selected such that, from device to device, bit, byte or character positions of the devices' respective results are shuffled, rotated or otherwise ordered differently.

Optionally the second memory locations of the devices are selected such that, from device to device, bit, byte or character positions of the devices' respective results are shuffled, rotated or otherwise ordered differently.
Optionally the present invention provides a device having a bit-pattern stored in it in accordance with the method of storing a bit-pattern in each of a plurality of devices, each of the devices having a memory, the method comprising, for each device:

(a) determining a first memory location; and (b) storing the bit-pattern at the first memory location;

wherein the first memory locations are different in at least a plurality of the respective devices.

Optionally, in a further embodiment there is provided a device having a bit-pattern and a result stored in it in accordance with the method comprising:

applying a function to the first bit pattern and a second bit pattern, thereby to generate a result; and storing the result in the first memory location, thereby indirectly storing the first bit-pattern.

Optionally, in a further embodiment there is provided a device having a bit-pattern and a result stored in it in accordance with the method wherein the first memory locations of the devices are selected such that, from device to device, there is no overlap of the positions of at least some of the bits, bytes or characters of the devices' respective results.

Optionally there is provided a plurality of devices having respective bit-patterns stored in them in accordance with the method of storing a bit-pattern in each of a plurality of devices, each of the devices having a memory, the method comprising, for each device:

(a) determining a first memory location; and (b) storing the bit-pattern at the first memory location;

wherein the first memory locations are different in at least a plurality of the respective devices.
Optionally, in a further embodiment there is provided a plurality of devices having respective bit-patterns and results stored in them in accordance with the method comprising:

applying a function to the first bit pattern and a second bit pattern, thereby to generate a result; and storing the result in the first memory location, thereby indirectly storing the first bit-pattern.

Optionally there is provided a plurality of devices having respective bit-patterns and results stored in them in accordance with the method wherein the first memory locations of the devices are selected such that, from device to device, there is no overlap of the positions of at least some of the bits, bytes or characters of the devices' respective results.

Optionally there is provided a device having a bit-pattern stored in it in accordance with the method of storing a bit-pattern in each of a plurality of devices, each of the devices having a memory, the method comprising, for each device:

(a) determining a first memory location; and (b) storing the bit-pattern at the first memory location;

wherein the first memory locations are different in at least a plurality of the respective devices.

Optionally there is provided a device having a bit-pattern and a result stored in it in accordance with the method comprising:

applying a function to the first bit pattern and a second bit pattern, thereby to generate a result; and storing the result in the first memory location, thereby indirectly storing the first bit-pattem.

Optionally there is provided a device having a bit-pattern and a result stored in it in accordance with the method wherein the first memory locations of the devices are selected such that, from device to device, there is no overlap of the positions of at least some of the bits, bytes or characters of the devices' respective results.

Optionally there is provided a plurality of devices having respective bit pattems stored in them in accordance with the method of storing a bit-pattern in each of a plurality of devices, each of the devices having a memory, the method comprising, for each device:

(a) determining a first memory location; and (b) storing the bit-pattern at the first memory location;

wherein the first memory locations are different in at least a plurality of the respective devices.
Optionally there is provided a plurality of devices having a bit-pattecn and a result stored in them in accordance with the method comprising:

applying a function to the first bit pattern and a second bit pattern, thereby to generate a result; and storing the result in the first memory location, thereby indirectly storing the first bit-pattern.

Optionally there is provided a plurality of devices having a bit-pattern and a result stored in them in accordance with the method wherein the first memory locations of the devices are selected such that, from device to device, there is no overlap of the positions of at least some of the bits, bytes or characters of the devices' respective results.

Optionally there is provided a method implemented in a first entity configured to authenticate a digital signature supplied by a second entity, wherein one of the entities includes a base key and the other of the entities includes a variant key and a bit-pattern, the variant key being based on the result of applying a one way function to the base key and the bit-pattern, the digital signature having been generated by the second entity using its key to digitally signing at least part of data to be authenticated, the fust entity being configured to:

(a) receive the digital signature from the second entity;
(b) receive the data; and (c) authenticate the digital signature based on the received data and the first entity's key.

Optionally there is provided a method implemented in a first entity including:
a first bit-pattern a non-volatile memory storing resource data, a first base key for use with at least a first variant key;

a second variant key for use with a second base key, the second variant key being the result of a one way function applied to: the second base key; and the fust bit-pattern or a modified bit-pattern based on the first bit-pattern.

Optionally there is provided a method for enabling or disabling a verification process of a first entity in response to a predetermined event, the first entity having at least one associated bit-pattern and at least one variant key, each of the variant keys having been generated by applying a one way function to: a base key; and one or more of the at least one bit-patterns, respectively; or one or more alternative bit patterns, each of the alternative bit-patterns being based on one or the at least one bit-patterns, the method including the method including:

(a) determining that the predetermined event has happened; and (b) enabling or disabling at least one of the first variant keys in response the predetermined event.

Optionally there is provided a method implemented in a system for enabling authenticated communication between a first entity and at least one other entity, the system including a second entity, wherein:

the first entity and the second entity share transport keys; and the second entity includes at least one authentication key configured to be transported from the second entity to the first entity using the transport keys, the authentication key being usable to enable the authenticated communication by the first entity.

Optionally there is provided a method for storing a first bit-pattern in non-volatile memory of a device, the method comprising:

(a) applying a one way function to a'second bit-pattern associated with the device, thereby to generate a first result;

(b) applying a second function to the first result and the fust bit-pattern, thereby to generate a second result;
and (c) storing the second result in the memory, thereby indirectly storing the first bit-pattern.

Optionally there is provided a method for storing at least one functionally identical code segment in each of a plurality of devices, each of the devices having a memory, the method comprising, for each device:

(a) determining a first memory location; and (b) storing a first of the at least one code segments in the memory at the first memory location;
wherein the first memory location is different in at least a plurality of the respective devices.

Optionally there is provided a method for providing a sequence of nonces (RO, Rl, R2, ... ) commencing with a current seed of a sequence of seeds (xl, x2, x3,...), the method comprising:

(a) applying a one-way function to the current seed, thereby to generate a current nonce; (b) outputting the current nonce;

(c) using the current seed to generate a next seed in a sequence of seeds, the seed so generated becoming the current seed; and (c) repeating steps (a) to (c) as required to generate further nonces in the sequence of nonces.

Optionally there is provided a method for storing multiple first bit-patterns in non-volatile memory of a device, the method comprising, for each of the first bit-patterns to be stored:

(a) applying a one way function to a third bit-pattern based on a second bit-pattern associated with the device, thereby to generate a first result;

(b) applying a second function to the first result and the first bit-pattern, thereby to generate a second result;
and (c) storing the second result in the memory, thereby indirectly storing the first bit-pattern;

wherein the third bit-patterns used for the respective first bit-patterns are relatively unique compared to each other.

In a fortieth aspect the present invention provides a method of storing at least one functionally identical code segment in each of a plurality of devices, each of the devices having a memory, the method comprising, for each device:

(a) determining a first memory location; and (b) storing a first of the at least one code segments in the memory at the first memory location;
wherein the first memory location is different in at least a plurality of the respective devices.

Optionally at least one of the code segments in each of the devices includes an initial instruction, the initial instruction being located at an initial instruction location, the initial instruction location being the same in all the devices.

Optionally the initial instruction in each device is indicative of the first memory location of that device.

Optionally the initial instruction is indicative of the first memory location by including an explicit reference to the memory location.

Optionally the initial instruction is indicative of the first memory location by including an implicit reference to the memory location.

Optionally the implicit reference is a pointer to a location at which the address of the fust memory location is stored.

Optionally the implicit reference is a pointer to a register that holds the address of the first memory location.
Optionally step (a) includes randomly selecting the fust memory location.

Optionally step (a) includes selecting the first memory location based on a stochastic process or mechanism.

Optionally step (a) includes selecting the first memory location from an existing list or sequence of inemory locations.

Optionally each device including at least one additional memory location, each of the at least one code segments being located at the first memory location or one of the additional memory locations, wherein each of the code segments includes at least one'instruction that is indicative of one of the at least one additional memory locations or of the first memory location, and wherein at least one of the additional memory locations corresponding to one of the code segments is different in at least a plurality of the respective devices.

Optionally the at least one instruction is indicative of the additional or first memory location by including an explicit reference to the memory location.

Optionally the at least one instruction is indicative of the additional or first memory location by including an implicit reference to the memory location.

Optionally the implicit reference is a pointer to a location at which the address of the additional or first memory location is stored.

Optionally the implicit reference is a pointer to a register that holds the address of the additional or first memory location.

Optionally the implicit reference is an index into an address table wherein the address table holds the location of the additional or first memory location.

Optionally the memory is non-volatile memory.
Optionally the memory is non-volatile memory.

Optionally there is provided a method implemented in a first entity configured to authenticate a digital signature supplied by a second entity, wherein one of the entities includes a base key and the other of the entities includes a variant key and a bit-pattern, the variant key being based on the result of applying a one way function to the base key and the bit-pattern, the digital signature having been generated by the second entity using its key to digitally signing at least part of data to be authenticated, the first entity being configured to:

(a) receive the digital signature from the second entity;
(b) receive the data; and (c) authenticate the digital signature based on the received data and the first entity's key.
Optionally there is provided a method implemented in a first entity including:

a first bit-pattern a non-volatile memory storing resource data, a first base key for use with at least a first variant key;

a second variant key for use with a second base key, the second variant key being the result of a one way function applied to: the second base key; and the first bit-pattern or a modified bit-pattern based on the first bit-pattern.

Optionally there is provided a method for enabling or disabling a verification process of a first entity in response to a predetermined event, the first entity having at least one associated bit-pattern and at least one variant key, each of the variant keys having been generated by applying a one way function to: a base key; and one or more of the at least one bit-patterns, respectively; or one or more alternative bit patterns, each of the alternative bit-patterns being based on one or the at least one bit-patterns, the method including the method including:

(a) determining that the predetermined event has happened; and (b) enabling or disabling at least one of the first variant keys in response the predetermined event.
Optionally there is provided a method implemented in a system for enabling authenticated communication between a first entity and at least one other entity, the system including a second entity, wherein:

the first entity and the second entity share transport keys; and the second entity includes at least one authentication key configured to be transported from the second entity to the first entity using the transport keys, the authentication key being usable to enable the authenticated communication by the first entity.

Optionally there is provided a method for storing a first bit-pattern in non-volatile memory of a device, the method comprising:

(a) applying a one way function to a second bit-pattern associated with the device, thereby to generate a first result;

(b) applying a second function to the first result and the first bit-pattern, thereby to generate a second result;
and (c) storing the second result in the memory, thereby indirectly storing the first bit-pattern.

Optionally there is provided a method for storing a bit-pattem in each of a plurality of devices, each of the devices having a memory, the method comprising, for each device:

(a) determining a first memory location; and (b) storing the bit-pattern at the first memory location;

wherein the first memory locations are different in at least a plurality of the respective devices.

Optionally there is provided a method for providing a sequence of nonces (RO, Rl, R2, ... ) commencing with a current seed of a sequence of seeds (xl, x2, x3,...), the method comprising:

(a) applying a one-way function to the current seed, thereby to generate a current nonce; (b) outputting the current nonce;

(c) using the current seed to generate a next seed in a sequence of seeds, the seed so generated becoming the current seed; and (c) repeating steps (a) to (c) as required to generate further nonces in the sequence of nonces.

Optionally there is provided a method for storing multiple first bit-patterns in non-volatile memory of a device, the method comprising, for each of the first bit-patterns to be stored:

(a) applying a one way function to a third bit-pattern based on a second bit-pattern associated with the device, thereby to generate a first result;

(b) applying a second function to the first result and the first bit-pattern, thereby to generate a second result;
and (c) storing the second result in the memory, thereby indirectly storing the first bit-pattern;

wherein the third bit-patterns used for the respective first bit-patterns are relatively unique compared to each other.

In a forty first aspect the present invention provides a method for providing a sequence of nonces (RO, Rl, R2, ...
) commencing with a current seed of a sequence of seeds (xl, x2, x3,...), the method comprising:

(a) applying a one-way function to the current seed, thereby to generate a current nonce; (b) outputting the current nonce;

(c) using the current seed to generate a next seed in a sequence of seeds, the seed so generated becoming the current seed; and (c) repeating steps (a) to (c) as required to generate further nonces in the sequence of nonces.

Optionally xl is generated based on an initial seed x0, the initial seed having been generated by a random number generator.

Optionally, the initial seed xO having been generated based on a stochastic process.

Optionally the next seed is generated from the current seed on the basis of a second function.
Optionally the second function is less cryptographically strong than the one way function.
Optionally the second function is additive.

Optionally the second function is a linear feedback shift register function.

Optionally the one way function is a hash function.
Optionally the hash function is SHA1.

In a further aspect the present invention provides a device for generating a sequence of nonces (RO, Rl, R2, ... ), the device including:

memory for storing a current seed of a sequence of seeds (xl, x2, x3,...)' a processor configured to:

(a) apply a one way function to the current seed to generate a current nonce;
and (b) use the current seed to generate a next seed in the sequence of seeds, the seed so generated becoming the current seed; and (c) storing the current seed in memory.

Optionally the device is configured to generate xl in the seed sequence based on an initial seed x0, the initial seed being stored in a non-volatile manner in the device.

Optionally xO was generated by a random number generator.

Optionally, the initial seed xO having been generated based on a stochastic process.

Optionally the processor is configured to generate the next seed by applying a second function to the current seed.
Optionally the second function is less cryptographically strong than the one way function.

Optionally the second function is additive.

Optionally the second function is a linear feedback shift register function.

Optionally the memory is non-volatile.
Optionally the memory is flash memory.

Optionally the device comprises one or more integrated circuits.
Optionally the device comprises a monolithic integrated circuit.
Optionally the one way function is a hash function.

Optionally the hash function is SHA1.

In a further aspect the present invention provides a method of manufacturing a series of devices, each of the devices for generating a sequence of nonces (RO, RI, R2, ... ), the device including:

memory for storing a current seed of a sequence of seeds (xl, x2, x3,...)' a processor configured to:

(a) apply a one way function to the current seed to generate a current nonce;
and (b) use the current seed to generate a next seed in the sequence of seeds, the seed so generated becoming the current seed; and (c) storing the current seed in memory.

and including a non-volatile memory, the method comprising:

generating a bit-pattern on the basis of a random or pseudo random process;
storing the bit-pattern in a non-volatile manner in the device;

wherein the device is configured to use the bit-pattem as an initial current seed, and to store subsequent generated seeds in the non-volatile memory.

Optionally the step of storing the bit-pattern in a non-volatile manner includes storing the value in a place other than in the non-volatile memory.

Optionally the bit-pattern is stored in non-erasable fonm.

Optionally the method including the step of storing a program on the device, the program including the one way function for generating the current nonce from the current seed.

Optionally the one way function is a hash function.
Optionally the one way function is non-compressing.
Optionally the hash function is SHA1.

Optionally there is provided a method implemented in a first entity configured to authenticate a digital signature supplied by a second entity, wherein one of the entities includes a base key and the other of the entities includes a variant key and a bit-pattern, the variant key being based on the result of applying a one way function to the base key and the bit-pattern, the digital signature having been generated by the second entity using its key to digitally signing at least part of data to be authenticated, the first entity being configured to:

(a) receive the digital signature from the second entity;
(b) receive the data; and (c) authenticate the digital signature based on the received data and the first entity's key.

Optionally there is provided a method implemented in a fust entity including:
a first bit-pattem a non-volatile memory storing resource data, a first base key for use with at least a first variant key;

a second variant key for use with a second base key, the second variant key being the result of a one way function applied to: the second base key; and the first bit-pattern or a modified bit-pattem based on the first bit-pattem.

Optionally there is provided a method for enabling or disabling a verification process of a first entity in response to a predetermined event, the first entity having at least one associated bit-pattern and at least one variant key, each of the variant keys having been generated by applying a one way function to: a base key; and one or more of the at least one bit-patterns, respectively; or one or more alternative bit patterns, each of the alternative bit-patterns being based on one or the at least one bit-patterns, the method including the method including:

(a) determining that the predetermined event has happened; and (b) enabling or disabling at least one of the first variant keys in response the predetermined event.
Optionally there is provided a method implemented in a system for enabling authenticated communication between a first entity and at least one other entity, the system including a second entity, wherein:

the first entity and the second entity share transport keys; and the second entity includes at least one authentication key configured to be transported from the second entity to the first entity using the transport keys, the authentication key being usable to enable the authenticated communication by the first entity.

Optionally there is provided a method for storing a first bit-pattern in non-volatile memory of a device, the method comprising:

(a) applying a one way function to a second bit-pattern associated with the device, thereby to generate a first result;

(b) applying a second function to the first result and the first bit-pattern, thereby to generate a second result;
and (c) storing the second result in the memory, thereby indirectly storing the first bit-pattern.

Optionally there is provided a method for storing a bit-pattern in each of a plurality of devices, each of the devices having a memory, the method comprising, for each device:

(a) determining a first memory location; and (b) storing the bit-pattern at the first memory location;

wherein the first memory locations are different in at least a plurality of the respective devices.

Optionally there is provided a method for storing at least one functionally identical code segment in each of a plurality of devices, each of the devices having a memory, the method comprising, for each device:

(a) determining a first memory location; and (b) storing a first of the at least one code segments in the memory at the first memory location;
wherein the first memory location is different in at least a plurality of the respective devices.
Optionally there is provided a method for storing multiple first bit-patterns in non-volatile memory of a device, the method comprising, for each of the first bit-patterns to be stored:

(a) applying a one way function to a third bit-pattern based on a second bit-pattern associated with the device, thereby to generate a first result;

(b) applying a second function to the first result and the first bit-pattem, thereby to generate a second result;
and (c) storing the second result in the memory, thereby indirectly storing the first bit-pattern;

wherein the third bit-patterns used for the respective first bit-pattecns are relatively unique compared to each other.

In a forty second aspect the present invention provides a method of storing multiple first bit-patterns in non-volatile memory of a device, the method comprising, for each of the first bit-patterns to be stored:

(a) applying a one way function to a third bit-pattern based on a second bit-pattern associated with the device, thereby to generate a first result;

(b) applying a second function to the first result and the first bit-pattern, thereby to generate a second result;
and (c) storing the second result in the memory, thereby indirectly storing the first bit-pattern;

wherein the third bit-patterns used for the respective first bit-patterns are relatively unique compared to each other.

Optionally step (c) comprises:

(d) determining a first memory location; and (e) storing the second result at the first memory location.

Optionally step (d) includes randomly selecting the first memory location.

Optionally step (d) includes selecting the first memory location based on a stochastic process or mechanism.
Optionally step (d) includes selecting the first memory location from an existing list or sequence of memory locations.

Optionally each third bit-pattem is generated from the second bit-pattern by removing, adding or changing one or more bits, bytes or characters of the second bit-pattern.

Optionally each third bit-pattern is generated from the second bit-pattern by adding an index of one or more bits, bytes or characters to the second bit-pattern, the index having been added at any position of the identifier, including being appended before or after the identifier, or being distributed within the identifier.

Optionally the index added to the second bit-pattern for the respective second bit-patterns is derived from a series of indices.

Optionally the method includes the step of generating the index as required.

Optionally the one way function is more cryptographically secure than the second function.
Optionally the second function is a logical function.

Optionally the logical function is an XOR function.

Optionally the one way function is a hash function.
Optionally each of the first bit-patterns is a key.

Optionally the method further includes the step of storing one or more code segments in the memory, the code segments being configured to run on a processor of the device, thereby enabling the device to, for each of first bit-patterns to be retrieved:

generate the third-bit pattern corresponding to the first bit pattern to be retrieved;

apply the one way function to the third bit-pattern, thereby to generate the first result; and apply a third function to the first result and the second result corresponding to the first bit-pattem to be retrieved, thereby to generate that first bit-pattern;

wherein the third function is the inverse of the second function.
Optionally the third function and the second function are the same.

Optionally the second bit-pattern was generated randomly or pseudo-randomly.

Optionally method further including the step, performed prior to step (a), of determining the second bit-pattern.

Optionally determining the second bit-pattern includes generating the second bit-pattern randomly or pseudo-randomly.

Optionally determining the second bit-pattern includes generating the second bit-pattein based on a stochastic process or mechanism.

Optionally determining the second bit-pattern includes selecting the second-bit pattern from an existing list or sequence of bit-patterns.

In a further aspect the present invention provides a method of storing multiple first bit-patterns in nori-volatile memory of each of a plurality of devices, the method comprising, for each of the first bit-patterns to be stored:
(a) applying a one way function to a third bit-pattern based on a second bit-pattern associated with the device, thereby to generate a first result;

(b) applying a second function to the first result and the fust bit-pattern, thereby to generate a second result;
and (c) storing the second result in the memory, thereby indirectly storing the first bit-pattern;

wherein the third bit-patterns used for the respective first bit-patterns in each device are relatively unique with respect to each other, and the second bit-patterns of the respective devices are relatively unique with respect to each other.

Optionally step (c) comprises, for each device:
(d) determining a first memory location; and (e) storing the second result at the first memory location.

Optionally step (d) includes randomly selecting the first memory location.

Optionally step (d) includes selecting the first memory location based on a stochastic process or mechanism.
Optionally step (d) includes selecting the first memory location from an existing list or sequence of memory locations.

Optionally the first memory locations of the devices are selected such that, from device to device, there is no overlap of the positions of at least some of the bits, bytes or characters of the devices' respective second results.
Optionally the first memory locations of the devices are selected such that, from device to device, positions of at least some of the bits, bytes or characters of the devices' respective second results overlap.

Optionally the first memory locations of the devices are selected such that, from device to device, bit, byte or character positions of the devices' respective second results are shuffled, rotated or otherwise ordered differently.

Optionally the first memory locations of the devices are selected such that, from device to device, bit, byte or character positions of the devices' respective second results are shuffled, rotated or otherwise ordered differently.
Optionally for each device, each third bit-pattern is generated from the second bit-pattern by removing, adding or changing one or more bits, bytes or characters of the second bit-pattern.

Optionally for each device, each third bit-pattern is generated from the second bit-pattern by adding an index of one or more bits, bytes or characters to the second bit-pattern, the index having been added at any position of the identifier, including being distributed within the identifier.

Optionally the index added to the second bit-pattern for the respective second bit-patterns is derived from a series of indices.

Optionally the method includes the step, for each device, of generating the index as required.

Optionally the one way function is more cryptographically secure than the second function.

Optionally the second function is a logical function.
Optionally the logical function is an XOR function.
Optionally the one way function is a hash function.
Optionally each of the first bit-patterns is a key.

Optionally the method further includes the step of storing one or more code segments in the memory of each device, the code segments being configured to run on a processor of each device, thereby enabling each device to, for each of first bit-patterns to be retrieved:

generate the third-bit pattern corresponding to the first bit pattern to be retrieved;

apply the one way function to the third bit-pattern, thereby to generate the first result; and apply a third function to the first result and the second result corresponding to the first bit-pattern to be retrieved, thereby to generate that first bit-pattern;

wherein the third function is the inverse of the second function.
Optionally the third function and the second function are the same.

Optionally the second bit-pattern for each device was generated randomly or pseudo-randomly.

Optionally the second bit-pattern for each device was generated based on a stochastic process or mechanism.

Optionally there is provided a device manufactured in accordance with the method of storing multiple first bit-patterns in non-volatile memory of a device, the method comprising, for each of the fust bit-patterns to be stored:
(a) applying a one way function to a third bit-pattern based on a second bit-pattern associated with the device, thereby to generate a first result;

(b) applying a second function to the first result and the fust bit-pattern, thereby to generate a second result;
and (c) storing the second result in the memory, thereby indirectly storing the first bit-pattern;

wherein the third bit-patterns used for the respective first bit-patterns are relatively unique compared to each other.

Optionally there is provided a device manufactured in accordance with the method of method of storing multiple first bit-patterns in non-volatile memory of a device, the method comprising, for each of the first bit-patterns to be stored:

(a) applying a one way function to a third bit-pattern based on a second bit-pattern associated with the device, thereby to generate a first result;

(b) applying a second function to the first result and the first bit-pattern, thereby to generate a second result;
and (c) storing the second result in the memory, thereby indirectly storing the first bit-pattern;

wherein the third bit-patterns used for the respective first bit-patterns are relatively unique compared to each other; andfurther including the step of storing one or more code segments in the memory, the code segments being configured to run on a processor of the device, thereby enabling the device to, for each of first bit-patterns to be retrieved:

generate the third-bit pattern corresponding to the first bit pattern to be retrieved;

apply the one way function to the third bit-pattem, thereby to generate the first result; and apply a third function to the first result and the second result corresponding to the first bit-pattern to be retrieved, thereby to generate that first bit-pattern;

wherein the third function is the inverse of the second function.

Optionally there is provided a plurality of devices manufactured in accordance with the method of storing multiple first bit-pattems in non-volatile memory of each of a plurality of devices, the method comprising, for each of the first bit-patterns to be stored:

(a) applying a one way function to a third bit-pattern based on a second bit-pattern associated with the device, thereby to generate a first result;

(b) applying a second function to the first result and the first bit-pattern, thereby to generate a second result;
and (c) storing the second result in the memory, thereby indirectly storing the first bit-pattern;

wherein the third bit-patterns used for the respective first bit-patterns in each device are relatively unique with respect to each other, and the second bit-pattetns of the respective devices are relatively unique with respect to each other.

Optionally there is provided a plurality of devices manufactured in accordance with the of method of storing multiple first bit-patterns in non-volatile memory of each of a plurality of devices, the method comprising, for each of the first bit-patterns to be stored:

(a) applying a one way function to a third bit-pattern based on a second bit-pattern associated with the device, thereby to generate a first result;

(b) applying a second function to the first result and the fust bit-pattern, thereby to generate a second result;
and (c) storing the second result in the memory, thereby indirectly storing the first bit-pattern;

wherein the third bit-patterns used for the respective first bit-pattems in each device are relatively unique with respect to each other, and the second bit-patterns of the respective devices are relatively unique with respect to each other; and further including the step of storing one or more code segments in the memory of each device, the code segments being configured to run on a processor of each device, thereby enabling each device to, for each of first bit-patterns to be retrieved:

generate the third-bit pattern corresponding to the first bit pattern to be retrieved;

apply the one way function to the third bit-pattern, thereby to generate the first result; and apply a third function to the first result and the second result corresponding to the first bit-pattern to be retrieved, thereby to generate that first bit-pattern;

wherein the third function is the inverse of the second function.

Optionally there is provided a method implemented in a first entity configured to authenticate a digital signature supplied by a second entity, wherein one of the entities includes a base key and the other of the entities includes a variant key and a bit-pattern, the variant key being based on the result of applying a one way function to the base key and the bit-pattem, the digital signature having been generated by the second entity using its key to digitally signing at least part of data to be authenticated, the first entity being configured to:

(a) receive the digital signature from the second entity;

(b) receive the data; and (c) authenticate the digital signature based on the received data and the first entity's key.

Optionally there is provided a method implemented in a first entity including:
a first bit-pattern a non-volatile memory storing resource data, a first base key for use with at least a first variant key;

a second variant key for use with a second base key, the second variant key being the result of a one way function applied to: the second base key; and the fust bit-pattern or a modified bit-pattern based on the first bit-pattern.

Optionally there is provided a method for enabling or disabling a verification process of a first entity in response to a predetermined event, the first entity having at least one associated bit-pattern and at least one variant key, each of the variant keys having been generated by applying a one way function to: a base key; and one or more of the at least one bit-patterns, respectively; or one or more alternative bit patterns, each of the alternative bit-patterns being based on one or the at least one bit-patterns, the method including the method including:

(a) determining that the predetermined event has happened; and (b) enabling or disabling at least one of the first variant keys in response the predetermined event.

Optionally there is provided a method implemented in a system for enabling authenticated communication between a fust entity and at least one other entity, the system including a second entity, wherein:

the first entity and the second entity share transport keys; and the second entity includes at least one authentication key configured to be transported from the second entity to the first entity using the transport keys, the authentication key being usable to enable the authenticated communication by the first entity.

Optionally there is provided a method for storing a first bit-pattern in non-volatile memory of a device, the method comprising:

(a) applying a one way function to a second bit-pattern associated with the device, thereby to generate a first result;

(b) applying a second function to the first result and the first bit-pattern, thereby to generate a second result;
and (c) storing the second result in the memory, thereby indirectly storing the first bit-pattern.

A method according to claim 1, for storing a bit-pattern in each of a plurality of devices, each of the devices having a memory, the method comprising, for each device:

(a) determining a first memory location; and (b) storing the bit-pattern at the first memory location;

wherein the first memory locations are different in at least a plurality of the respective devices.
Optionally there is provided a method for storing at least one functionally identical code segment in each of a plurality of devices, each of the devices having a memory, the method comprising, for each device:

(a) determining a first memory location; and (b) storing a first of the at least one code segments in the memory at the first memory location;
wherein the first memory location is different in at least a plurality of the respective devices.
Optionally there is provided a method for providing a sequence of nonces (RO, Rl, R2, ... ) commencing with a current seed of a sequence of seeds (xl, x2, x3,...), the method comprising:

(a) applying a one-way function to the current seed, thereby to generate a current nonce; (b) outputting the current nonce;

(c) using the current seed to generate a next seed in a sequence of seeds, the seed so generated becoming the current seed; and (c) repeating steps (a) to (c) as required to generate further nonces in the sequence of nonces.

BRIEF DESCRIPTION OF THE DRAWINGS
Figure 1. Example State machine notation Figure 2. Single SoPEC A4 Simplex system Figure 3. Dual SoPEC A4 Simplex system Figure 4. Dual SoPEC A4 Duplex system Figure 5. Dual SoPEC A3 simplex system Figure 6. Quad SoPEC A3 duplex system Figure 7. SoPEC A4 Simplex system with extra SoPEC used as DRAM storage Figure 8. SoPEC A4 Simplex system with network connection to Host PC
Figure 9. Document data flow Figure 10. Pages containing different numbers of bands Figure 11. Contents of a page band Figure 12. Page data path from host to SoPEC
Figure 13. Page structure Figure 14. SoPEC System Top Level partition Figure 15. Proposed SoPEC CPU memory map (not to scale) Figure 16. Possible USB Topologies for Multi-SoPEC systems Figure 17. CPU block diagram Figure 18. CPU bus transactions Figure 19. State machine for a CPU subsystem slave Figure 20. Proposed SoPEC CPU memory map (not to scale) Figure 21. MMU Sub-block partition, external signal view Figure 22. MMU Sub-block partition, internal signal view Figure 23. DRAM Write buffer Figure 24. DIU waveforms for multiple transactions Figure 25. SoPEC LEON CPU core Figure 26. Cache Data RAM wrapper Figure 27. Realtime Debug Unit block diagram Figure 28. Interrupt acknowledge cycles for a single and pending interrupts Figure 29. UHU Dataflow Figure 30. UHU Basic Block Diagram Figure 31. ehci_ohci Basic Block Diagram.
Figure 32. uhu_ctl Figure 33. uhu_dma Figure 34. EHCI DIU Buffer Partition Figure 35. UDU Sub-block Partition Figure 36. Local endpoint packet buffer partitioning Figure 37. Circular buffer operation Figure 38. Overview of Control Transfer State Machine Figure 39. Writing a Setup packet at the start of a Control-In transfer Figure 40. Reading Control-In data Figure 41. Status stage of Control-In transfer Figure 42. Writing Control-Out data Figure 43. Reading Status In data during a Control-Out transfer Figure 44. Reading bullc/interrupt IN data Figure 45. A bulk OUT transfer Figure 46. VCI slave port bus adapter Figure 47. Duty Cycle Select Figure 48. Low Pass filter structure Figure 49. GPIO partition Figure 50. GPIO Partition (continued) Figure 51. LEON UART block diagram Figure 52. Input de-glitch RTL diagram Figure 53. Motor control RTL diagram Figure 54. BLDC controllers RTL diagram Figure 55. Period Measure RTL diagram Figure 56. Frequency Modifier sub-block partition Figure 57. Fixed point bit allocation Figure 58. Frequency Modifier structure Figure 59. Line sync generator diagram Figure 60. HSI timing diagram Figure 61. Centronic interface timing diagram Figure 62. Parallel Port EPP read and write transfers Figure 63. ECP forward Data and command cycles Figure 64. ECP Reverse Data and command cycles Figure 65. 68K example read and write access Figure 66. Non burst, non pipelined read and write accesses with wait states Figure 67. Generic Flash Read and Write operation Figure 68. Serial flash example 1 byte read and write protocol Figure 69. MMI sub-block partition Figure 70. MMI Engine sub-block diagram Figure 71. Instruction field bit allocation Figure 72. Circular buffer operation Figure 73. ICU partition Figure 74. Interrupt clear state diagram Figure 75. Timers sub-block partition diagram Figure 76. Watchdog timer RTL diagram Figure 77. Generic timer RTL diagram Figure 78. Pulse generator RTL diagram Figure 79. SoPEC clock relationship Figure 80. CPR block partition Figure 81. Reset Macro block structure Figure 82. Reset control logic state machine Figure 83. PLL and Clock divider logic Figure 84. PLL control state machine diagram Figure 85. Clock gate logic diagram Figure 86. SoPEC clock distribution diagram Figure 87. Sub-block partition of the ROM block Figure 88. LSS master system-level interface Figure 89. START and STOP conditions Figure 90. LSS transfer of 2 data bytes Figure 91. Example of LSS write to a QA Chip Figure 92. Example of LSS read from QA Chip Figure 93. LSS block diagram Figure 94. Example LSS multi-command transaction Figure 95. Start and stop generation based on previous bus state Figure 96. S master state machine Figure 97. LSS Master timing Figure 98. SoPEC System Top Level partition Figure 99. Shared read bus with 3 cycle random DRAM read accesses Figure 100. Interleaving CPU and non-CPU read accesses Figure 101. Interleaving read and write accesses with 3 cycle random DRAM
accesses Figure 102. Interleaving write accesses with 3 cycle random DRAM accesses Figure 103. Read protocol for a SoPEC Unit making a single 256-bit access Figure 104. Read protocol for a CPU making a single 256-bit access Figure 105. Write Protocol shown for a SoPEC Unit making a single 256-bit access Figure 106. Protocol for a posted, masked, 128-bit write by the CPU.
Figure 107. Write Protocol shown for CDU making four contiguous 64-bit accesses Figure 108. Timeslot based arbitration Figure 109. Timeslot based arbitration with separate pointers Figure 110. Example (a), separate read and write arbitration Figure 111. Example (b), separate read and write arbitration Figure 112. Example (c), separate read and write arbitration Figure 113. DIU Partition Figure 114. DIU Partition Figure 115. Multiplexing and address translation logic for two memory instances Figure 116. Timing of dau_dcu valid, dcu_dau adv and dcu dau_wadv Figure 117. DCU state machine Figure 118. Random read timing Figure 119. Random write timing Figure 120. Refresh timing Figure 121. Page mode write timing Figure 122. Timing of non-CPU DIU read access Figure 123. Timing of CPU DIU read access Figure 124. CPU DIU read access Figure 125. Timing of CPU DIU write access Figure 126. Timing of a non-CDU / non-CPU DIU write access Figure 127. Timing of CDU DIU write access Figure 128. Command multiplexor sub-block partition Figure 129. Command Multiplexor timing at DIU requestors interface Figure 130. Generation of re arbitrate and re_arbitrate wadv Figure 131. CPU Interface and Arbitration Logic Figure 132. Arbitration timing Figure 133. Setting RotationSync to enable a new rotation.
Figure 134. Timeslot based arbitration Figure 135. Timeslot based arbitration with separate pointers Figure 136. CPU pre-access write lookahead pointer Figure 137. Arbitration hierarchy Figure 138. Hierarchical round-robin priority comparison Figure 139. Read Multiplexor partition.
Figure 140. Read Multiplexor timing Figure 141. Read command queue (4 deep buffer) Figure 142. State-machines for shared read bus accesses Figure 143. Read Multiplexor timing for back to back shared read bus transfers Figure 144. Write multiplexor partition Figure 145. Block diagram of PCU
Figure 146. PCU accesses to PEP registers Figure 147. Command Arbitration and execution Figure 148. DRAM command access state machine Figure 149. Outline of contone data flow with respect to CDU
Figure 150. Block diagram of CDU
Figure 151. State machine to read compressed contone data Figure 152. DRAM storage arrangement for a single line of JPEG 8x8 blocks in 4 colors Figure 153. State machine to write decompressed contone data Figure 154. Lead-in and lead-out clipping of contone data in multi-SoPEC
environment Figure 155. Block diagram of CFU
Figure 156. DRAM storage arrangement for a single line of JPEG blocks in 4 colors Figure 157. State machine to read decompressed contone data from DRAM
Figure 158. Block diagram of color space converter Figure 159. High level block diagram of LBD in context Figure 160. Schematic outline of the LBD and the SFU
Figure 161. Block diagram of lossless bi-level decoder Figure 162. Stream decoder block diagram Figure 163. Command controller block diagram Figure 164. State diagram for the Command Controller (CC) state machine Figure 165. Next Edge Unit block diagram Figure 166. Next edge unit buffer diagram Figure 167. Next edge unit edge detect diagram Figure 168. State diagram for the Next Edge Unit (NEU) state machine Figure 169. Line fill unit block diagram Figure 170. State diagram for the Line Fill Unit (LFU) state machine Figure 171. Bi-level DRAM buffer Figure 172. Interfaces between LBD/SFU/HCU
Figure 173. SFU Sub-Block Partition Figure 174. LBDPrevLineFifo Sub-block Figure 175. Timing of signals on the LBDPrevLineFIFO interface to DIU and Address Generator Figure 176. Timing of signals on LBDPrevLineFIFO interface to DIU and Address Generator Figure 177. LBDNextLineFifo Sub-block Figure 178. Timing of signals on LBDNextLineFIFO interface to DIU and Address Generator Figure 179. LBDNextLineFIFO DIU Interface State Diagram Figure 180. LDB to SFU write interface Figure 181. LDB to SFU read interface (within a line) Figure 182. HCUReadLineFifo Sub-block Figure 183. DIU Write Interface Figure 184. DIU Read Interface multiplexing by select hr. fp' If Figure 185. DIU read request arbitration logic Figure 186. Address Generation Figure 187. X scaling control unit Figure 188. Y scaling control unit Figure 189. Overview of X and Y scaling at HCU interface Figure 190. High level block diagram of TE in context Figure 191. Example QR Code developed by Denso of Japan Figure 192. Netpage tag structure Figure 193. Netpage tag with data rendered at 1600 dpi (magnified view) Figure 194. Example of 2x2 dots for each block of QR code Figure 195. Placement of tags for portrait & landscape printing Figure 196. General representation of tag placement Figure 197. Composition of SoPEC's tag format structure Figure 198. Simple 3x3 tag structure Figure 199. 3x3 tag redesigned for 21 x 21 area (not simple replication) Figure 200. TE Block Diagram Figure 201. TE Hierarchy Figure 202. Tag Encoder Top-Level FSM
Figure 203. Logic to combine dot information and Encoded Data Figure 204. Generation of Lastdotintag Figure 205. Generation of Dot Position Valid Figure 206. Generation of write enable to the TFU
Figure 207. Generation of Tag Dot Number Figure 208. TDI Architecture Figure 209. Data Flow Through the TDI
Figure 210. Raw tag data interface block diagram Figure 211. RTDI State Flow Diagram Figure 212. Relationship between te_endoftagdata, te_startofbandstore and te endofbandstore Figure 213. TDi State Flow Diagram Figure 214. Mapping of the tag data to codewords 0-7 for (15,5) encoding.
Figure 215. Coding and mapping of uncoded Fixed Tag Data for (15,5) RS encoder Figure 216. Mapping of pre-coded Fixed Tag Data Figure 217. Coding and mapping of Variable Tag Data for (15,7) RS encoder Figure 218. Coding and mapping of uncoded Fixed Tag Data for (15,7) RS encoder Figure 219. Mapping of 2D decoded Variable Tag Data, DataRedun = 0 Figure 220. Simple block diagram for an m=4 Reed Solomon Encoder Figure 221. RS Encoder I/O diagram Figure 222. (15,5) & (15,7) RS Encoder block diagram Figure 223. (15,5) RS Encoder timing diagram Figure 224. (15,7) RS Encoder timing diagram Figure 225. Circuit for multiplying by a3 Figure 226. Adding two field elements, (15,5) encoding.
Figure 227. RS Encoder Implementation Figure 228. encoded tag data interface Figure 229. Breakdown of the Tag Format Structure Figure 230. TFSI FSM State Flow Diagram Figure 231. TFS Block Diagram Figure 232. Table A address generator Figure 233. Table C interface block diagram Figure 234. Table B interface block diagram Figure 235. Interfaces between TE, TFU and HCU
Figure 236. 16-byte FIFO in TFU
Figure 237. High level block diagram showing the HCU and its external interfaces Figure 238. Block diagram of the HCU
Figure 239. Block diagram of the control unit Figure 240. Block diagram of determine advdot unit Figure 241. Page structure Figure 242. Block diagram of margin unit Figure 243. Block diagram of dither matrix table interface Figure 244. Example reading lines of dither matrix from DRAM
Figure 245. State machine to read dither matrix table Figure 246. Contone dotgen unit Figure 247. Block diagram of dot reorg unit Figure 248. HCU to DNC interface (also used in DNC to DWU, LLU to PHI) Figure 249. SFU to HCU (all feeders to HCU) Figure 250. Representative logic of the SFU to HCU interface Figure 251. High level block diagram of DNC
Figure 252. Dead nozzle table format Figure 253. Set of dots operated on for error diffusion Figure 254. Block diagram of DNC
Figure 255. Sub-block diagram of ink replacement unit Figure 256. Dead nozzle table state machine Figure 257. Logic for dead nozzle removal and ink replacement Figure 258. Sub-block diagram of error diffusion unit Figure 259. Maximum length 32-bit LFSR used for random bit generation Figure 260. High level data flow diagram of DWU in context Figure 261. Printhead Nozzle Layout for conceptual 36 Nozzle AB single segment printhead Figure 262. Paper and printhead nozzles relationship (example with D1=D2=5) Figure 263. Dot line store logical representation Figure 264. Conceptual view of 2 adjacent printhead segments possible row alignment Figure 265. Conceptual view of 2 adjacent printhead segments row alignment (as seen by the LLU) Figure 266. Even dot order in DRAM (13312 dot wide line) Figure 267. Dotline FIFO data structure in DRAM (LLU specification) Figure 268. DWU partition Figure 269. Sample dot_data generation for color 0 even dot Figure 270. Buffer address generator sub-block Figure 271. DIU Interface sub-block Figure 272. Interface controller state diagram Figure 273. High level data flow diagram of LLU in context Figure 274. Paper and printhead nozzles relationship (example with Di=D2=5) Figure 275. Conceptual view of vertically misaligned printhead segment rows (external) Figure 276. Conceptual view of vertically misaligned printhead segment rows (internal) Figure 277. Conceptual view of color dependent vertically misaligned printhead segment rows (intemal) Figure 278. Conceptual horizontal misalignment between segments Figure 279. Relative positions of dot fired (example cases) Figure 280. Example left and right margins Figure 281. Dot data generated and transmitted order Figure 282. Dotline FIFO data structure in DRAM (LLU specification) Figure 283. LLU partition Figure 284. DIU interface Figure 285. Interface controller state diagram Figure 286. Address generator logic Figure 287. Write pointer state machine Figure 288. PHI to linking printhead connection (Single SoPEC) Figure 289. PHI to linking printhead connection (2 SoPECs) Figure 290. CPU command word format Figure 291. Example data and command sequence on a print head channel Figure 292. PHI block partition Figure 293. Data generator state diagram Figure 294. PHI mode Controller Figure 295. Encoder RTL diagram Figure 296. 28-bit scrambler Figure 297. Printing with 1 SoPEC
Figure 298. Printing with 2 SoPECs (existing hardware) Figure 299. Each SoPEC generates dot data and writes directly to a single printhead Figure 300. Each SoPEC generates dot data and writes directly to a single printhead Figure 301. Two SoPECs generate dots and transmit directly to the larger printhead Figure 302. Serial Load Figure 303. Parallel Load Figure 304. Two SoPECs generate dot data but only one transmits directly to the larger printhead Figure 305. Odd and Even nozzles on same shift register Figure 306. Odd and Even nozzles on different shift registers Figure 307. Interwoven shift registers Figure 308. Linking Printhead Concept Figure 309. Linking Printhead 30ppm Figure 310. Linking Printhead 60ppm Figure 311. Theoretical 2 tiles assembled as A-chip / A-chip - right angle join Figure 312. Two tiles assembled as A-chip / A-chip Figure 313. Magnification of color n in A-chip / A-chip Figure 314. A-chip / A-chip growing offset Figure 315. A-chip / A-chip aligned nozzles, sloped chip placement Figure 316. Placing multiple segments together Figure 317. Detail of a single segment in a multi-segment configuration Figure 318. Magnification of inter-slope compensation Figure 319. A-chip / B-chip Figure 320. A-chip / B-chip multi-segment printhead Figure 321. Two A-B-chips linked together Figure 322. Two A-B-chips with on-chip compensation Figure 323. Frequency modifier block diagram Figure 324. Output frequency error versus input frequency Figure 325. Output frequency error including K
Figure 326. Optimised for output jitter <0.2%, FyS = 48MHz, K=25 Figure 327. Direct form II biquad Figure 328. Output response and internal nodes Figure 329. Butterworth filter (Fc=0.005) gain error versus input level Figure 330. Step response Figure 331. Output frequency quantisation (K=2~25) Figure 332. Jitter attenuation with a 2nd order Butterworth, F, = 0.05 Figure 333. Period measurement and NCO cumulative error Figure 334. Stepped input frequency and output response Figure 335. Block diagram overview Figure 336. Multiply/divide unit Figure 337. Power-on-reset detection behaviour Figure 338. Brown-out detection behaviour Figure 339. Adapting the IBM POR macro for brown-out detection Figure 340. Deglitching of power-on-reset signal Figure 341. Deglitching of brown-out detector signal Figure 342. Proposed top-level solution Figure 343. First Stage Image Format Figure 344. Second Stage Image Format Figure 345. Overall Logic Flow Figure 346. Initialisation Logic Flow Figure 347. Load & Verify Second Stage Image Logic Flow Figure 348. Load from LSS Logic Flow Figure 349. Load from USB Logic Flow Figure 350. Verify Header and Load to RAM Logic Flow Figure 351. Body Verification Logic Flow Figure 352. Run Application Logic Flow Figure 353. Boot ROM Memory Layout Figure 354. Overview of LSS buses for single SoPEC system Figure 355. Overview of LSS buses for single SoPEC printer Figure 356. Overview of LSS buses for simplest two-SoPEC printer Figure 357. Overview of LSS buses for alternative two-SoPEC printer Figure 358. SoPEC System top level partition Figure 359. Print construction and Nozzle position Figure 360. Conceptual horizontal misplacement between segments Figure 361. Printhead row positioning and default row firing order Figure 362. Firing order of fractionally misaligned segment Figure 363. Example of yaw in printhead IC misplacement Figure 364. Vertical nozzle spacing Figure 365. Single printhead chip plus connection to second chip Figure 366. Two printheads connected to form a larger printhead Figure 367. Colour arrangement.
Figure 368. Nozzle Offset at Linking Ends Figure 369. Bonding Diagram Figure 370. MEMS Representation.
Figure 371. Line Data Load and Firing, properly placed Printhead, Figure 372. Simple Fire order Figure 373. Micro positioning Figure 374. Measurement convention Figure 375. Scrambler implementation Figure 376. Block Diagram Figure 377. Netlist hierarchy Figure 378. Unit cell schematic Figure 379. Unit cell arrangement into chunks Figure 380. Unit Cell Signals Figure 381. Core data shift registers Figure 382. Core Profile logical connection Figure 383. Colunm SR Placement Figure 384. TDC block diagram Figure 385. TDC waveform Figure 386. TDC construction Figure 387. FPG Outputs (vposition = 0) Figure 388. DEX block diagram Figure 389. Data sampler Figure 390. Data Eye Figure 391. scrambler/descrambler Figure 392. Aligner state machine Figure 393. Disparity decoder Figure 394. CU command state machine Figure 395. Example transaction Figure 396. clk phases Figure 397. Planned tool flow DETAILED DESCRIPTION OF PREFERRED EMBODIMENT

Various aspects of the preferred and other embodiments will now be described.

It will be appreciated that the following description is a highly detailed exposition of the hardware and associated methods that together provide a printing system capable of relatively high resolution, high speed and low cost printing compared to prior art systems.

Much of this description is based on technical design documents, so the use of words like "must", "should"
and "will", and all others that suggest limitations or positive attributes of the performance of a particular product, should not be interpreted as applying to the invention in general.
These comments, unless clearly refen ing to the invention in general, should be considered as desirable or intended features in a particular design rather than a requirement of the invention. The intended scope of the invention is defined in the claims.

Also throughout this description, "printhead module" and "printhead" are used somewhat interchangeably.
Technically, a "printhead" comprises one or more "printhead modules", but occasionally the former is used to refer to the latter. It should be clear from the context which meaning should be allocated to any use of the word "printhead".

PRINT SYSTEM OVERVIEW

This document describes the SoPEC ASIC (Small office home office Print Engine Controller) suitable for use in price sensitive SoHo printer products. The SoPEC ASIC is intended to be a relatively low cost solution for linking printhead control, replacing the multichip solutions in larger more professional systems with a single chip. The increased cost competitiveness is achieved by integrating several systems such as a modified PEC1 printing pipeline, CPU control system, peripherals and memory sub-system onto one SoC ASIC, reducing component count and simplifying board design. SoPEC contains features making it suitable for multifunction or "all-in-one" devices as well as dedicated printing systems.

This section will give a general introduction to Memjet printing systems, introduce the components that make a linking printhead system, describe a number of system architectures and show how several SoPECs can be used to achieve faster, wider and/or duplex printing. The section "SoPEC ASIC"
describes the SoC SoPEC
ASIC, with subsections describing the CPU, DRAM and Print Engine Pipeline subsystems. Each section gives a detailed description of the blocks used and their operation within the overall print system.

Basic features of the preferred embodiment of SoPEC include:
= Continuous 30ppm operation for 1600dpi output at A4/Letter.

= Linearly scalable (multiple SoPECs) for increased print speed and/or page width.

= 192MHz internal system clock derived from low-speed crystal input = PEP processing pipeline, supports up to 6 color channels at 1 dot per channel per clock cycle = Hardware color plane decompression, tag rendering, halftoning and compositing = Data formatting for Linking Printhead = Flexible compensation for dead nozzles, printhead misalignment etc.

= Integrated 20Mbit (2.5MByte) DRAM for print data and CPU program store = LEON SPARC v8 32-bit RISC CPU

= Supervisor and user modes to support multi-threaded software and security = 1kB each of I-cache and D-cache, both direct mapped, with optimized 256-bit fast cache update.
= 1 x USB2.0 device port and 3 x USB2.0 host ports (including integrated PHYs) = Support high speed (480Mbit/sec) and full speed (12Mbit/sec) modes of USB2.0 = Provide interface to host PC, other SoPECs, and external devices e.g.
digital camera = Enable alternative host PC interfaces e.g. via external USB/ethenmet bridge = Glueless high-speed serial LVDS interface to multiple Linking Printhead chips = 64 remappable GPIOs, selectable between combinations of integrated system control components:
= 2 x LSS interfaces for QA chip or serial EEPROM

= LED drivers, sensor inputs, switch control outputs = Motor controllers for stepper and brushless DC motors = Microprogrammed multi-protocol media interface for scanner, external RAM/Flash, etc.

= 112-bit unique ID plus 112-bit random number on each device, combined for security protocol support = IBM Cu-11 0.13 micron CMOS process, 1.5V core supply, 3.3V IO.
= 208 pin Plastic Quad Flat Pack DEFINITIONS

The following terms are used throughout this specification:

CPU Refers to CPU core, caching system and MMU.

Host A PC providing control and print data to a Memjet printer.

ISCMaster In a multi-SoPEC system, the ISCMaster (Inter SoPEC Communication Master) is the SoPEC device that initiates communication with other SoPECs in the system.
The ISCMaster interfaces with the host.

ISCSIave In a multi-SoPEC system, an ISCSIave is a SoPEC device that responds to communication initiated by the ISCMaster.
LEON Refers to the LEON CPU core.

LineSyncMaster The LineSyncMaster device generates the line synchronisation pulse that all SoPECs in the system must synchronise their line outputs to.

Linking Printhead Refers to a page-width printhead constructed from multiple linking printhead ICs Linking Printhead IC A MEMS IC. Multiple ICs link together to form a complete printhead. An A4/Letter page width printhead requires 11 printhead ICs.

Multi-SoPEC Refers to SoPEC based print system with multiple SoPEC devices Netpage Refers to page printed with tags (normally in infrared ink).

PEC1 Refers to Print Engine Controller version 1, precursor to SoPEC used to control printheads constructed from multiple angled printhead segments.

PrintMaster The PrintMaster device is responsible for coordinating all aspects of the print operation. There may only be one PrintMaster in a system.

QA Chip Quality Assurance Chip Storage SoPEC A SoPEC used as a DRAM store and which does not print.

Tag Refers to pattern which encodes information about its position and orientation which allow it to be optically located and its data contents read.

ACRONYM AND ABBREVIATIONS

The following acronyms and abbreviations are used in this specification CFU Contone FIF053 Unit CPU Central Processing Unit DIU DRAM Interface Unit DNC Dead Nozzle Compensator DRAM Dynamic Random Access Memory DWU DotLine Writer Unit GPIO General Purpose Input Output HCU Halftoner Compositor Unit ICU Interrupt Controller Unit LDB Lossless Bi-level Decoder LLU Line Loader Unit LSS Low Speed Serial interface MEMS Micro Electro Mechanical System MMI Multiple Media Interface MMU Memory Management Unit PCU SoPEC Controller Unit PHI PrintHead Interface PHY USB multi-port Physical Interface PSS Power Save Storage Unit RDU Real-time Debug Unit ROM Read Only Memory SFU Spot FIFO Unit SMG4 Silverbrook Modified Group 4.

SoPEC Small office home office Print Engine Controller SRAM Static Random Access Memory TE Tag Encoder TFU Tag FIFO Unit TIM Timers Unit UDU USB Device Unit UHU USB Host Unit USB Universal Serial Bus PSEUDOCODE NOTATION

In general the pseudocode examples use C like statements with some exceptions.
Symbol and naming convections used for pseudocode.

// Comment = Assignment Operator equal, not equal, less than, greater than Operator addition, subtraction, multiply, divide, modulus &,1,~, , ,- Bitwise AND, bitwise OR, bitwise exclusive OR, left shift, right shift, complement AND,OR,NOT Logical AND, Logical OR, Logical inversion [XX:YY] Array/vector specifier {a, b, c} Concatenation operation ++, -- Increment and decrement 3 Register and signal naming conventions In general register naming uses the C style conventions with capitalization to denote word delimiters. Signals use RTL style notation where underscore denote word delimiters. There is a direct translation between both conventions. For example the CmdSourceFifo register is equivalent to cmd source_ f:fo signal.

State machines are described using the pseudocode notation outlined above.
State machine descriptions use the convention of underline to indicate the cause of a transition from one state to another and plain text (no underline) to indicate the effect of the transition i.e. signal transitions which occur when the new state is entered. A sample state machine is shown in Figure 1.

The preferred embodiment linking printhead produces 1600 dpi bi-level dots. On low-diffusion paper, each ejected drop forms a 22.5 m diameter dot. Dots are easily produced in isolation, allowing dispersed-dot dithering to be exploited to its fullest. Since the preferred form of the linking printhead is pagewidth and operates with a constant paper velocity, color planes are printed in good registration, allowing dot-on-dot printing. Dot-on-dot printing minimizes 'muddying' of midtones caused by inter-color bleed.

A page layout may contain a mixture of images, graphics and text. Continuous-tone (contone) images and graphics are reproduced using a stochastic dispersed-dot dither. Unlike a clustered-dot (or amplitude-modulated) dither, a dispersed-dot (or frequency-modulated) dither reproduces high spatial frequencies (i.e.
image detail) almost to the limits of the dot resolution, while simultaneously reproducing lower spatial frequencies to their full color depth, when spatially integrated by the eye. A
stochastic dither matrix is carefully designed to be free of objectionable low-frequency patterns when tiled across the image. As such its size typically exceeds the minimum size required to support a particular number of intensity levels (e.g.
16x16x 8 bits for 257 intensity levels).

Human contrast sensitivity peaks at a spatial frequency of about 3 cycles per degree of visual field and then falls off logarithmically, decreasing by a factor of 100 beyond about 40 cycles per degree and becoming inuneasurable beyond 60 cycles per degree. At a normal viewing distance of 12 inches (about 300mm), this translates roughly to 200-300 cycles per inch (cpi) on the printed page, or 400-600 samples per inch according to Nyquist's theorem.

In practice, contone resolution above about 300 ppi is of limited utility outside special applications such as medical imaging. Offset printing of magazines, for example, uses contone resolutions in the range 150 to 300 ppi. Higher resolutions contribute slightly to color error through the dither.

Black text and graphics are reproduced directly using bi-level black dots, and are therefore not anti-aliased (i.e. low-pass filtered) before being printed. Text should therefore be supersampled beyond the perceptual limits discussed above, to produce smoother edges when spatially integrated by the eye. Text resolution up to about 1200 dpi continues to contribute to perceived text sharpness (assuming low-diffusion paper).

A Netpage printer, for example, may use a contone resolution of 267 ppi (i.e.
1600 dpi / 6), and a black text and graphics resolution of 800 dpi. A high end office or departmental printer may use a contone resolution of 320 ppi (1600 dpi / 5) and a black text and graphics resolution of 1600 dpi.
Both formats are capable of exceeding the quality of commercial (offset) printing and photographic reproduction.

The SoPEC device can be used in several printer configurations and architectures.

In the general sense, every preferred embodiment SoPEC-based printer architecture will contain:
= One or more SoPEC devices.
= One or more linking printheads.
= Two or more LSS busses.

= Two or more QA chips.

= Connection to host, directly via USB2.0 or indirectly.

= Connections between SoPECs (when multiple SoPECs are used).

Some example printer configurations as outlined in Section 6.2. The various system components are outlined briefly in Section 6.1.

6.1 SYSTEM COMPONENTS

6.1.1 SoPEC Print Engine Controller The SoPEC device contains several system on a chip (SoC) components, as well as the print engine pipeline control application specific logic.

6.1.1.1 Print Engine Pipeline (PEP) Logic The PEP reads compressed page store data from the embedded memory, optionally decompresses the data and formats it for sending to the printhead. The print engine pipeline functionality includes expanding the page image, dithering the contone layer, compositing the black layer over the contone layer, rendering of Netpage tags, compensation for dead nozzles in the printhead, and sending the resultant image to the linking printhead.
6.1.1.2 Embedded CPU

SoPEC contains an embedded CPU for general-purpose system configuration and management. The CPU
performs page and band header processing, motor control and sensor monitoring (via the GPIO) and other system control functions. The CPU can perform buffer management or repprt buffer status to the host. The CPU can optionally run vendor application specific code for general print control such as paper ready monitoring and LED status update.

6.1.1.3 Embedded Memory Buffer A 2.5Mbyte embedded memory buffer is integrated onto the SoPEC device, of which approximately 2Mbytes are available for compressed page store data. A compressed page is divided into one or more bands, with a number of bands stored in memory. As a band of the page is consumed by the PEP
for printing a new band can be downloaded. The new band may be for the current page or the next page.

Using banding it is possible to begin printing a page before the complete compressed page is downloaded, but care must be taken to ensure that data is always available for printing or a buffer undernm may occur.

A Storage SoPEC acting as a memory buffer (Section 6.2.6) could be used to provide guaranteed data delivery.

6.1.1.4 Embedded USB2.0 Device Controller The embedded single-port USB2.0 device controller can be used either for interface to the host PC, or for communication with another SoPEC as an ISCSIave. It accepts compressed page data and control commands from the host PC or ISCMaster SoPEC, and transfers the data to the embedded memory for printing or downstream distribution.

6.1.1.5 Embedded USB2.0 Host Controller The embedded three-port USB2.0 host controller enables communication with other SoPEC devices as a ISCMaster, as well as interfacing with external chips (e.g. for Ethernet connection) and external USB devices, such as digital cameras.

6.1.1.6 Embedded Device/Motor Controllers SoPEC contains embedded controllers for a variety of printer system components such as motors, LEDs etc, which are controlled via SoPEC's GPIOs. This minimizes the need for circuits external to SoPEC to build a complete printer system.

6.1.2 Linking Printhead The printhead is constructed by abutting a number of printhead ICs together.
Each SoPEC can drive up to 12 printhead ICs at data rates up to 30ppm or 6 printhead ICs at data rates up to 60ppm. For higher data rates, or wider printheads, multiple SoPECs must be used.

6.1.3 LSS interface bus Each SoPEC device has 2 LSS system buses for communication with QA devices for system authentication and ink usage accounting. The number of QA devices per bus and their position in the system is unrestricted with the exception that PRINTER_QA and INK_QA devices should be on separate LSS busses.

6.1.4 QA devices Each SoPEC system can have several QA devices. Normally each printing SoPEC
will have an associated PRINTER_QA. Ink cartridges will contain an INK QA chip. PRINTER_QA and INK_QA
devices should be on separate LSS busses. All QA chips in the system are physically identical with flash memory contents defming PRINTER_QA from INKQA chip.

6.1.5 Connections between SoPECs In a multi-SoPEC system, the primary communication channel is from a USB2.0 Host port on one SoPEC
(the ISCMaster), to the USB2.0 Device port of each of the other SoPECs (ISCSIaves). If there are more ISCSIave SoPECs than available USB Host ports on the ISCMaster, additional connections could be via a USB Hub chip, or daisy-chained SoPEC chips. Typically one or more of SoPEC's GPIO signals would also be used to communicate specific events between multiple SoPECs.

6.1.6 Non-USB Host PC Communication The communication between the host PC and the ISCMaster SoPEC may involve an external chip or subsystem, to provide a non-USB host interface, such as ethernet or WiFi. This subsystem may also contain memory to provide an additional buffered band/page store, which could provide guaranteed bandwidth data deliver to SoPEC during complex page prints.

6.2 POSSIBLE SOPEC SYSTEMS

Several possible SoPEC based system architectures exist. The following sections outline some possible architectures. It is possible to have extra SoPEC devices in the system used for DRAM storage. The QA chip configurations shown are indicative of the flexibility of LSS bus architecture, but not limited to those configurations.

6.2.1 A4 Simplex at 30 ppm with I SoPEC device In Figure 2, a single SoPEC device is used to control a linking printhead with 11 printhead ICs. The SoPEC
receives compressed data from the host through its USB device port. The compressed data is processed and transferred to the printhead. This arrangement is limited to a speed of 30ppm.
The single SoPEC also controls all printer components such as motors, LEDs, buttons etc, either directly or indirectly.

6.2.2 A4 Simplex at 60 ppm with 2 SoPEC devices In Figure 3, two SoPECs control a single linking printhead, to provide 60ppm A4 printing. Each SoPEC
drives 5 or 6 of the printheads ICs that make up the complete printhead. SoPEC
#0 is the ISCMaster, SoPEC
#1 is an ISCSIave. The ISCMaster receives all the compressed page data for both SoPECs and re-distributes the compressed data for the ISCSIave over a local USB bus. There is a total of 4MBytes of page store memory available if required. Note that, if each page has 2MBytes of compressed data, the USB2.0 interface to the host needs to run in high speed (not full speed) mode to sustain 60ppm printing. (In practice, many compressed pages will be much smaller than 2MBytes). The control of printer components such as motors, LEDs, buttons etc, is shared between the 2 SoPECs in this configuration.

6.2.3 A4 Duplex with 2 SoPEC devices In Figure 4, two SoPEC devices are used to control two printheads. Each printhead prints to opposite sides of the same page to achieve duplex printing. SoPEC #0 is the ISCMaster, SoPEC #1 is an ISCSIave. The ISCMaster receives all the compressed page data for both SoPECs and re-distributes the compressed data for the ISCSIave over a local USB bus. This configuration could print 30 double-sided pages per minute.

6.2.4 A3 Simplex with 2 SoPEC devices In Figure 5, two SoPEC devices are used to control one A3 linking printhead, constructed from 16 printhead ICs. Each SoPEC controls 8 printhead ICs. This system operates in a similar manner to the 60ppm A4 system in Figure 3, although the speed is limited to 30ppm at A3, since each SoPEC
can only drive 6 printhead ICs at 60ppm speeds. A total of 4Mbyte of page store is available, this allows the system to use compression rates as in a single SoPEC A4 architecture, but with the increased page size of A3.

6.2.5 A3 Duplex with 4 SoPEC devices In Figure 6 a four SoPEC system is shown. It contains 2 A3 linking printheads, one for each side of an A3 page. Each printhead contain 16 printhead ICs, each SoPEC controls 8 printhead ICs. SoPEC #0 is the ISCMaster with the other SoPECs as ISCSlaves. Note that all 3 USB Host ports on SoPEC #0 are used to communicate with the 3 ISCSIave SoPECs. In total, the system contains 8Mbytes of compressed page store (2Mbytes per SoPEC), so the increased page size does not degrade the system print quality, from that of an A4 simplex printer. The ISCMaster receives all the compressed page data for all SoPECs and re-distributes the compressed data over the local USB bus to the ISCSlaves. This configuration could print 30 double-sided A3 sheets per minute.

6.2.6 SoPEC DRAM storage solution: A4 Simplex with I printing SoPEC and I
memory SoPEC

Extra SoPECs can be used for DRAM storage e.g. in Figure 7 an A4 simplex printer can be built with a single extra SoPEC used for DRAM storage. The DRAM SoPEC can provide guaranteed bandwidth delivery of data to the printing SoPEC. SoPEC configurations can have multiple extra SoPECs used for DRAM storage.

6.2.7 Non-USB connection to Host PC

Figure 8 shows a configuration in which the connection from the host PC to the printer is an ethernet network, rather than USB. In this case, one of the USB Host ports on SoPEC interfaces to a external device that provide ethemet-to-USB bridging. Note that some networking software support in the bridging device might be required in this configuration. A Flash RAM will be required in such a system, to provide SoPEC with driver software for the Ethernet bridging function.

7.1 OVERALL FLOW FOR PC-BASED PRINTING

Because of the page-width nature of the linking printhead, each page must be printed at a constant speed to avoid creating visible artifacts. This means that the printing speed can't be varied to match the input data rate.
Document rasterization and document printing are therefore decoupled to ensure the printhead has a constant supply of data. A page is never printed until it is fully rasterized. This can be achieved by storing a compressed version of each rasterized page image in memory.

This decoupling also allows the RIP(s) to run ahead of the printer when rasterizing simple pages, buying time to rasterize more complex pages.

Because contone color images are reproduced by stochastic dithering, but black text and line graphics are reproduced directly using dots, the compressed page image format contains a separate foreground bi-level black layer and background contone color layer. The black layer is composited over the contone layer after the contone layer is dithered (although the contone layer has an optional black component). A fmal layer of Netpage tags (in infrared, yellow or black ink) is optionally added to the page for printout.

Figure 9 shows the flow of a document from computer system to printed page.
7.2 MULTI-LAYER COMPRESSION

At 267 ppi for example, an A4 page (8.26 inches x 11.7 inches) of contone CMYK
data has a size of 26.3MB.
At 320 ppi, an A4 page of contone data has a size of 37.8MB. Using lossy contone compression algorithms such as JPEG, contone images compress with a ratio up to 10:1 without noticeable loss of quality, giving compressed page sizes of 2.63MB at 267 ppi and 3.78 MB at 320 ppi.

At 800 dpi, an A4 page of bi-level data has a size of 7.4MB. At 1600 dpi, a Letter page of bi-level data has a size of 29.5 MB. Coherent data such as text compresses very well. Using lossless bi-level compression algorithms such as SMG4 fax as discussed in Section 8.1.2.3.1, ten-point plain text compresses with a ratio of about 50:1. Lossless bi-level compression across an average page is about 20:1 with 10:1 possible for pages which compress poorly. The requirement for SoPEC is to be able to print text at 10:1 compression. Assuming 10:1 compression gives compressed page sizes of 0.74 MB at 800 dpi, and 2.95 MB at 1600 dpi.

Once dithered, a page of CMYK contone image data consists of 116MB of bi-level data. Using lossless bi-level compression algorithms on this data is pointless precisely because the optimal dither is stochastic - i.e.
since it introduces hard-to-compress disorder.

Netpage tag data is optionally supplied with the page image. Rather than storing a compressed bi-level data layer for the Netpage tags, the tag data is stored in its raw form. Each tag is supplied up to 120 bits of raw variable data (combined with up to 56 bits of raw fixed data) and covers up to a 6mm x 6mm area (at 1600 dpi). The absolute maximum number of tags on a A4 page is 15,540 when the tag is only 2mm x 2mm (each tag is 126 dots x 126 dots, for a total coverage of 148 tags x 105 tags).
15,540 tags of 128 bits per tag gives a compressed tag page size of 0.24 MB.

The multi-layer compressed page image format therefore exploits the relative strengths of lossy JPEG contone image compression, lossless bi-level text compression, and tag encoding. The format is compact enough to be storage-efficient, and simple enough to allow straightforward real-time expansion during printing.

Since text and images normally don't overlap, the normal worst-case page image size is image only, while the normal best-case page image size is text only. The addition of worst case Netpage tags adds 0.24MB to the page image size. The worst-case page image size is text over image plus tags.
The average page size assumes a quarter of an average page contains images. Table 1 shows data sizes for a compressed A4 page for these different options.

Table 1. Data sizes for A4 page (8.26 Inches x 11.7 inches) , .
,W
7 P u Ppi Cdntone contone 8 pi 1600 dpi bi-t 1 level Image only (contone), 10:1 2.63 MB 3.78 MB
compression Text only (bi-level), 10:1 0.74 MB 2.95 MB
compression Netpage tags, 1600 dpi 0.24 MB 0.24 MB
Worst case (text + image + tags) 3.61 MB 6.67 MB
Average (text + 25% image + tags) 1.64 MB 4.25 MB

7.3 DOCUMENT PROCESSING STEPS

The Host PC rasterizes and compresses the incoming document on a page by page basis. The page is restructured into bands with one or more bands used to construct a page. The compressed data is then transferred to the SoPEC device directly via a USB link, or via an external bridge e.g. from ethernet to USB.
A complete band is stored in SoPEC embedded memory. Once the band transfer is complete the SoPEC
device reads the compressed data, expands the band, normalizes contone, bi-level and tag data to 1600 dpi and transfers the resultant calculated dots to the linking printhead.

The document data flow is = The RIP software rasterizes each page description and compress the rasterized page image.

= The infrared layer of the printed page optionally contains encoded Netpage tags at a programmable density.

= The compressed page image is transferred to the SoPEC device via the USB (or ethernet), normally on a band by band basis.

= The print engine takes the compressed page image and starts the page expansion.
= The first stage page expansion consists of 3 operations performed in parallel = expansion of the JPEG-compressed contone layer = expansion of the SMG4 fax compressed bi-level layer = encoding and rendering of the bi-level tag data.

= The second stage dithers the contone layer using a programmable dither matrix, producing up to four bi-level layers at full-resolution.

= The third stage then composites the bi-level tag data layer, the bi-level SMG4 fax de-compressed layer and up to four bi-level JPEG de-compressed layers into the full-resolution page image.
= A fixative layer is also generated as required.

= The last stage formats and prints the bi-level data through the linking printhead via the printhead interface.

The SoPEC device can print a full resolution page with 6 color planes. Each of the color planes can be generated from compressed data through any channel (either JPEG compressed, bi-level SMG4 fax compressed, tag data generated, or fixative channel created) with a maximum number of 6 data channels from page RIP to linking printhead color planes.

The mapping of data channels to color planes is programmable. This allows for multiple color planes in the printhead to map to the same data channel to provide for redundancy in the printhead to assist dead nozzle compensation.

Also a data channel could be used to gate data from another data channel. For example in stencil mode, data from the bilevel data channel at 1600 dpi can be used to filter the contone data channel at 320 dpi, giving the effect of 1600 dpi edged contone images, such as 1600dpi color text.

7.4 PAGE SIZE AND COMPLEXITY IN SOPEC

The SoPEC device typically stores a complete page of document data on chip.
The amount of storage available for compressed pages is limited to 2Mbytes, imposing a fixed maximum on compressed page size. A
comparison of the compressed image sizes in Table 1 indicates that SoPEC would not be capable of printing worst case pages unless they are split into bands and printing commences before all the bands for the page have been downloaded. The page sizes in the table are shown for comparison purposes and would be considered reasonable for a professional level printing system. The SoPEC
device is aimed at the consumer level and would not be required to print pages of that complexity. Target document types for the SoPEC
device are shown Table 2.

Table 2. Page content targets for SoPEC
. y , .. k ~:'.
P g er-~De~sc ' an ~ C~c n -Best Case picture Image, 267ppi with 3 colors, A4 size 8.26x11.7x267x267x3 1.97 @10:1 Full page text, 800dpi A4 size 8.26x11.7x800x800 @ 0.74 10:1 Mixed Graphics and Text 6x4x267x267x3 @ 5:1 1.55 - Image of 6 inches x 4 inches @ 267 ppi and 3 colors 800x800x73 @ 10:1 - Remaining area text -73 inchesZ, 800 dpi Best Case Photo, 3 Colors, 6.6 MegaPixel Image 6.6 Mpixel @ 10:1 2.00 If a document with more complex pages is required, the page RIP software in the host PC can determine that there is insufficient memory storage in the SoPEC for that document. In such cases the RIP software can take two courses of action:
= It can increase the compression ratio until the compressed page size will fit in the SoPEC device, at the expense of print quality, or = It can divide the page into bands and allow SoPEC to begin printing a page band before all bands for that page are downloaded.

Once SoPEC starts printing a page it cannot stop; if SoPEC consumes compressed data faster than the bands can be downloaded a buffer underrun error could occur causing the print to fail. A buffer undemm occurs if a line synchronisation pulse is received before a line of data has been transferred to the printhead.

Other options which can be considered if the page does not fit completely into the compressed page store are to slow the printing or to use multiple SoPECs to print parts of the page.
Alternatively, a number of methods are available to provide additional local page data storage with guaranteed bandwidth to SoPEC, for example a Storage SoPEC (Section 6.2.6).

7.5 OTHER PRINTING SOURCES

The preceding sections have described the document flow for printing from a host PC in which the RIP on the host PC does much of the management work for SoPEC. SoPEC also supports printing of images directly from other sources, such as a digital camera or scanner, without the intervention of a host PC.

In such cases, SoPEC receives image data (and associated metadata) into its DRAM via a USB host or other local media interface. Software running on SoPEC's CPU determines the image format (e.g. compressed or non-compressed, RGB or CMY, etc.), and optionally applies image processing algorithms such as color space conversion. The CPU then makes the data to be printed available to the PEP
pipeline. SoPEC allows various PEP pipeline stages to be bypassed, for example JPEG decompression. Depending on the format of the data to be printed, PEP hardware modules interact directly with the CPU to manage DRAM
buffers, to allow streaming of data from an image source (e.g. scanner) to the printhead interface without overflowing the limited on-chip DRAM.

When rendering a page, the RIP produces a page header and a number of bands (a non-blank page requires at least one band) for a page. The page header contains high level rendering parameters, and each band contains compressed page data. The size of the band will depend on the memory available to the RIP, the speed of the RIP, and the amount of memory remaining in SoPEC while printing the previous band(s). Figure 10 shows the high level data structure of a number of pages with different numbers of bands in the page.

Each compressed band contains a mandatory band header, an optional bi-level plane, optional sets of interleaved contone planes, and an optional tag data plane (for Netpage enabled applications). Since each of these planes is optional, the band header specifies which planes are included with the band. Figure 11 gives a high-level breakdown of the contents of a page band.

A single SoPEC has maximum rendering restrictions as follows:
= 1 bi-level plane = 1 contone interleaved plane set containing a maximum of 4 contone planes = 1 tag data plane = a linking printhead with a maximum of 12 printhead ICs The requirement for single-sided A4 single SoPEC printing at 30ppm is = average contone JPEG compression ratio of 10:1, with a local minimum compression ratio of 5:1 for a single line of interleaved JPEG blocks.

= average bi-level compression ratio of 10:1, with a local minimum compression ratio of 1:1 for a single line.

If the page contains rendering parameters that exceed these specifications, then the RIP or the Host PC must split the page into a format that can be handled by a single SoPEC.

In the general case, the SoPEC CPU must analyze the page and band headers and generate an appropriate set of register write commands to configure the units in SoPEC for that page. The various bands are passed to the destination SoPEC(s) to locations in DRAM determined by the host.

The host keeps a memory map for the DRAM, and ensures that as a band is passed to a SoPEC, it is stored in a suitable free area in DRAM. Each SoPEC receives its band data via its USB
device interface. Band usage information from the individual SoPECs is passed back to the host. Figure 12 shows an example data flow for a page destined to be printed by a single SoPEC.

SoPEC has an addressing mechanism that permits circular band memory allocation, thus facilitating easy memory management. However it is not strictly necessary that all bands be stored together. As long as the appropriate registers in SoPEC are set up for each band, and a given band is contiguous, the memory can be allocated in any way.

8.1 PRINT ENGINE EXAMPLE PAGE FORMAT

Note: This example is illustrative of the types of data a compressed page format may need to contain. The actual implementation details of page formats are a matter for software design (including embedded software on the SoPEC CPU); the SoPEC hardware does not assume any particular format.

This section describes a possible format of compressed pages expected by the embedded CPU in SoPEC. The format is generated by software in the host PC and interpreted by embedded software in SoPEC. This section indicates the type of information in a page format structure, but implementations need not be limited to this format. The host PC can optionally perform the majority of the header processing.

The compressed format and the print engines are designed to allow real-time page expansion during printing, to ensure that printing is never interrupted in the middle of a page due to data undemui.

The page format described here is for a single black bi-level layer, a contone layer, and a Netpage tag layer.
The black bi-level layer is defmed to composite over the contone layer.

The black bi-level layer consists of a bitmap containing a 1-bit opacity for each pixel. This black layer matte has a resolution which is an integer or non-integer factor of the printer's dot resolution. The highest supported resolution is 1600 dpi, i.e. the printer's full dot resolution.

The contone layer, optionally passed in as YCrCb, consists of a 24-bit CMY or 32-bit CMYK color for each pixel. This contone image has a resolution which is an integer or non-integer factor of the printer's dot resolution. The requirement for a single SoPEC is to support 1 side per 2 seconds A4/Letter printing at a resolution of 267 ppi, i.e. one-sixth the printer's dot resolution.

Non-integer scaling can be performed on both the contone and bi-level images.
Only integer scaling can be performed on the tag data.

The black bi-level layer and the contone layer are both in compressed form for efficient storage in the printer's internal memory.

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PLUS D'UN TOME.

NOTE : Pour les tomes additionels, veuillez contacter le Bureau canadien des brevets JUMBO APPLICATIONS/PATENTS

THIS SECTION OF THE APPLICATION/PATENT CONTAINS MORE THAN ONE
VOLUME

NOTE: For additional volumes, please contact the Canadian Patent Office NOM DU FICHIER / FILE NAME:

NOTE POUR LE TOME / VOLUME NOTE:

Claims

1. A method of at least partially compensating for errors in ink dot placement by at least one of a plurality of nozzles due to erroneous rotational displacement of a printhead module relative to a carrier, the nozzles being disposed on the printhead module, the method comprising the steps of:
(a) determining the rotational displacement;
(b) determining at least one correction factor that at least partially compensates for the ink dot displacement; and (c) using the correction factor to alter the output of the ink dots to at least partially compensate for the rotational displacement.

2. A method according to claim 1, wherein step (c) includes altering a timing of a fire signal to at least one of the nozzles on the basis of the correction factor, thereby to effect the at least partial compensation.

3. A method according to claim 1, wherein the nozzles are disposed in a plurality of rows, and step (c) includes reallocating at least one of the ink dots from at least one original print line to at least one alternate print line, thereby to effect the at least partial compensation.

4. A method according to claim 3, wherein step (c) further includes the step of altering a timing of fire signals to at least one of the nozzles on the basis of the correction factor, thereby to effect the at least partial compensation.

5. A method according to claim 4, wherein the altered fire signals are supplied to both reallocated ink dots and non-reallocated ink dots.

6. A method according to claim 1, wherein the correction factor is stored in a memory associated with the printhead.

7. A method according to claim 6, wherein the memory is mounted with the printhead, the printhead being mounted on the print engine.

8. A method according to claim 1, wherein the rotational displacement is roll.

9. A method according to claim 1, wherein the rotational displacement is yaw,.

10. A method according to claim 1, the printhead module being one of a plurality of printhead modules mounted on a carrier to form a printhead and the error in ink dot placement being an error relative to ink dots output by one or more of the other printhead modules

11. A method according to claim 1, wherein the printer is a pagewidth printer.

12. A method according to claim 1, wherein the printer is a pagewidth printer.

13. A printer controller programmed and configured to implement the method of claim 1.

14. A method according to claim 1, the method including expelling ink from a printhead module including at least one row that comprises a plurality of adjacent sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, the method comprising providing, for each set of nozzles, a fire signal in accordance with the sequence: [nozzle position 1, nozzle position n, nozzle position 2, nozzle position (n-1), ... , nozzle position x], wherein nozzle position x is at or adjacent the centre of the set of nozzles.

15. A method according to claim 1, the method including expelling ink from a printhead module including at least one row that comprises a plurality of sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, the method comprising the steps of:
(a) providing a fire signal to nozzles at a first and nth position in each set of nozzles;
(b) providing a fire signal to the next inward pair of nozzles in each set;
(c) in the event n is an even number, repeating step (b) until all of the nozzles in each set has been fired; and (d) in the event n is an odd number, repeating step (b) until all of the nozzles but a central nozzle in each set have been fired, and then firing the central nozzle.

16. A method according to claim 1, the method including manufacturing a plurality of printhead modules, at least some of which are capable of being combined in pairs to form bilithic pagewidth printheads, the method comprising the step of laying out each of the plurality of printhead modules on a wafer substrate, wherein at least one of the printhead modules is right-handed and at least another is left-handed.

17. A method according to claim 1, the method being performed in conjunction with a printhead module including:
at least one row of print nozzles;
at least two shift registers for shifting in dot data supplied from a data source to each of the at least one rows, wherein each print nozzle obtains dot data to be fired from an element of one of the shift registers.

18. A method according to claim 1, the method being performed in a printer comprising:
a printhead comprising at least a first elongate printhead module, the at least one printhead module including at least one row of print nozzles for expelling ink; and at least first and second printer controllers configured to receive print data and process the print data to output dot data to the printhead, wherein the first and second printer controllers are connected to a common input of the printhead.

19. A method according to claim 1, the method being performed in a printer comprising:
a printhead comprising first and second elongate printhead modules, the printhead modules being parallel to each other and being disposed end to end on either side of a join region;
at least first and second printer controllers configured to receive print data and process the print data to output dot data to the printhead, wherein the first printer controller outputs dot data only to the first printhead module and the second printer controller outputs dot data only to the second printhead module, wherein the printhead modules are configured such that no dot data passes between them.

20. A method according to claim 1, the method being performed in a printer comprising:
a printhead comprising first and second elongate printhead modules, the printhead modules being parallel to each other and being disposed end to end on either side of a join region, wherein the first printhead module is longer than the second printhead module;
at least first and second printer controllers configured to receive print data and process the print data to output dot data to the printhead, wherein: the first printer controller outputs dot data to both the first printhead module and the second printhead module; and the second printer controller outputs dot data only to the second printhead module.

21. A method according to claim 1, the method being performed in a printer comprising:
a printhead comprising first and second elongate printhead modules, the printhead modules being parallel to each other and being disposed end to end on either side of a join region, wherein the first printhead module is longer than the second printhead module;
at least first and second printer controllers configured to receive print data and process the print data to output dot data for the printhead, wherein: the first printer controller outputs dot data to both the first printhead module and the second controller; and the second printer controller outputs dot data to the second printhead module, wherein the dot data output by the second printer controller includes dot data it generates and at least some of the dot data received from the first printer controller.

22. A method according to claim 1, the method being performed in conjunction with a printer controller for supplying dot data to at least one printhead module and at least partially compensating for errors in ink dot placement by at least one of a plurality of nozzles on the printhead module due to erroneous rotational displacement of the printhead module relative to a carrier, the printer being configured to:
access a correction factor associated with the at least one printhead module;

determine an order in which at least some of the dot data is supplied to at least one of the at least one printhead modules, the order being determined at least partly on the basis of the correction factor, thereby to at least partially compensate for the rotational displacement; and supply the dot data to the printhead module.

23. A method according to claim 1, the method being performed in conjunction with a printer controller for supplying dot data to a printhead module having a plurality of nozzles for expelling ink, the printhead module including a plurality of thermal sensors, each of the thermal sensors being configured to respond to a temperature at or adjacent at least one of the nozzles, the printer controller being configured to modify operation of at least some of the nozzles in response to the temperature rising above a first threshold.

24. A method according to claim 1, the method being performed in conjunction with a printer controller for controlling a printhead comprising at least one monolithic printhead module, the at least one printhead module having a plurality of rows of nozzles configured to extend, in use, across at least part of a printable pagewidth of the printhead, the nozzles in each row being grouped into at least first and second fire groups, the printhead module being configured to sequentially fire, for each row, the nozzles of each fire group, such that each nozzle in the sequence from each fire group is fired simultaneously with respective corresponding nozzles in the sequence in the other fire groups, wherein the nozzles are fired row by row such that the nozzles of each row are all fired before the nozzles of each subsequent row, wherein the printer controller is configured to provide one or more control signals that control the order of firing of the nozzles.

25. A method according to claim 1, the method being performed in conjunction with a printer controller for outputting to a printhead module:
dot data to be printed with at least two different inks; and control data for controlling printing of the dot data;
the printer controller including at least one communication output, each or the communication output being configured to output at least some of the control data and at least some of the dot data for the at least two inks.

26. A method according to claim 1, the method being performed in conjunction with a printhead module including at least one row of printhead nozzles, at least one row including at least one displaced row portion, the displacement of the row portion including a component in a direction normal to that of a pagewidth to be printed.

27. A method according to claim 1, the method being performed in conjunction with a printer controller for supplying print data to at least one printhead module capable of printing a maximum of n of channels of print data, the at least one printhead module being configurable into:
a first mode, in which the printhead module is configured to receive data for a first number of the channels; and a second mode, in which the printhead module is configured to receive print data for a second number of the channels, wherein the first number is greater than the second number;
wherein the printer controller is selectively configurable to supply dot data for the first and second modes.

28. A method according to claim 1, the method being performed in conjunction with a printer controller for supplying data to a printhead comprising a plurality of printhead modules, the printhead being wider than a reticle step used in forming the modules, the printhead comprising at least two types of the modules, wherein each type is determined by its geometric shape in plan.

29. A method according to claim 1, the method being used in conjunction with a printer controller for supplying one or more control signals to a printhead module, the printhead module including at least one row that comprises a plurality of sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, such that:
(a) providing a fire signal to nozzles at a first and nth position in each set of nozzles;
(b) providing a fire signal to the next inward pair of nozzles in each set;
(c) in the event n is an even number, repeating step (b) until all of the nozzles in each set has been fired; and (d) in the event n is an odd number, repeating step (b) until all of the nozzles but a central nozzle in each set have been fired, and then firing the central nozzle.

30. A method according to claim 1, the method being used in conjunction with a printer controller for supplying one or more control signals to a printhead module, the printhead module including at least one row that comprises a plurality of adjacent sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, the method comprising providing, for each set of nozzles, a fire signal in accordance with the sequence: [nozzle position 1, nozzle position n, nozzle position 2, nozzle position (n-1), ... , nozzle position x], wherein nozzle position x is at or adjacent the centre of the set of nozzles.

31. A method according to claim 1, the method being performed in conjunction with a printer controller for supplying dot data to a printhead module comprising at least first and second rows configured to print ink of a similar type or color, at least some nozzles in the first row being aligned with respective corresponding nozzles in the second row in a direction of intended media travel relative to the printhead, the printhead module being configurable such that the nozzles in the first and second pairs of rows are fired such that some dots output to print media are printed to by nozzles from the first pair of rows and at least some other dots output to print media are printed to by nozzles from the second pair of rows, the printer controller being configurable to supply dot data to the printhead module for printing.

32. A method according to claim 1, the method being performed in conjunction with a printer controller for supplying dot data to at least one printhead module, the at least one printhead module comprising a plurality of rows, each of the rows comprising a plurality of nozzles for ejecting ink, wherein the printhead module includes at least first and second rows configured to print ink of a similar type or color, the printer controller being configured to supply the dot data to the at least one printhead module such that, in the event a nozzle in the first row is faulty, a corresponding nozzle in the second row prints an ink dot at a position on print media at or adjacent a position where the faulty nozzle would otherwise have printed it.

33. A method according to claim 1, the method being performed in conjunction with a printer controller for receiving first data and manipulating the first data to produce dot data to be printed, the print controller including at least two serial outputs for supplying the dot data to at least one printhead, wherein each of the serial outputs is configured to supply dot data for at least two channels of the at least one printhead.

34. A method according to claim 1, the method being performed in conjunction with a printhead module including:
at least one row of print nozzles;
at least first and second shift registers for shifting in dot data supplied from a data source, wherein each shift register feeds dot data to a group of nozzles, and wherein each of the groups of the nozzles is interleaved with at least one of the other groups of the nozzles.

35. A method according to claim 1, the method being performed in conjunction with a printhead capable of printing a maximum of n of channels of print data, the printhead being configurable into:
a first mode, in which the printhead is configured to receive print data for a first number of the channels; and a second mode, in which the printhead is configured to receive print data for a second number of the channels, wherein the first number is greater than the second number.

36. A method according to claim 1, the method being performed in conjunction with a printhead comprising a plurality of printhead modules, the printhead being wider than a reticle step used in forming the modules, the printhead comprising at least two types of the modules, wherein each type is determined by its geometric shape in plan.

37. A method according to claim 1, the method being performed in conjunction with a printhead module including at least one row that comprises a plurality of sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, such that, for each set of nozzles, a fire signal is provided in accordance with the sequence: [nozzle position 1, nozzle position n, nozzle position 2, nozzle position (n-1), ... , nozzle position x], wherein nozzle position x is at or adjacent the centre of the set of nozzles.

38. A method according to claim 1, the method being performed in conjunction with a printhead module including at least one row that comprises a plurality of adjacent sets of n adjacent nozzles, each of the nozzles being configured to expel the ink in response to a fire signal, the printhead being configured to output ink from nozzles at a first and nth position in each set of nozzles, and then each next inward pair of nozzles in each set, until:
in the event n is an even number, all of the nozzles in each set has been fired; and in the event n is an odd number, all of the nozzles but a central nozzle in each set have been fired, and then to fire the central nozzle.

39. A method according to claim 1, the method being performed in conjunction with a printhead module for receiving dot data to be printed using at least two different inks and control data for controlling printing of the dot data, the printhead module including a communication input for receiving the dot data for the at least two colors and the control data.

40. A method according to claim 1, the method being performed in conjunction with a printhead module including at least one row of printhead nozzles, at least one row including at least one displaced row portion, the displacement of the row portion including a component in a direction normal to that of a pagewidth to be printed.

41. A method according to claim 1, the method being performed in conjunction with a printhead module having a plurality of rows of nozzles configured to extend, in use, across at least part of a printable pagewidth, the nozzles in each row being grouped into at least first and second fire groups, the printhead module being configured to sequentially fire, for each row, the nozzles of each fire group, such that each nozzle in the sequence from each fire group is fired simultaneously with respective corresponding nozzles in the sequence in the other fire groups, wherein the nozzles are fired row by row such that the nozzles of each row are all fired before the nozzles of each subsequent row.

42. A method according to claim 1, the method being performed in conjunction with a printhead module comprising at least first and second rows configured to print ink of a similar type or color, at least some nozzles in the first row being aligned with respective corresponding nozzles in the second row in a direction of intended media travel relative to the printhead, the printhead module being configurable such that the nozzles in the first and second pairs of rows are fired such that some dots output to print media are printed to by nozzles from the first pair of rows and at least some other dots output to print media are printed to by nozzles from the second pair of rows.

43. A method according to claim 1, the method being performed in conjunction with a printer controller for providing data to a printhead module that includes:
at least one row of print nozzles;

at least first and second shift registers for shifting in dot data supplied from a data source, wherein each shift register feeds dot data to a group of nozzles, and wherein each of the groups of the nozzles is interleaved with at least one of the other groups of the nozzles.

44. A method according to claim 1, the method being performed in conjunction with a printhead module having a plurality of nozzles for expelling ink, the printhead module including a plurality of thermal sensors, each of the thermal sensors being configured to respond to a temperature at or adjacent at least one of the nozzles, the printhead module being configured to modify operation of the nozzles in response to the temperature rising above a first threshold.

45. A method according to claim 1, the method being performed in conjunction with a printhead module comprising a plurality of rows, each of the rows comprising a plurality of nozzles for ejecting ink, wherein the printhead module includes at least first and second rows configured to print ink of a similar type or color, and being configured such that, in the event a nozzle in the first row is faulty, a corresponding nozzle in the second row prints an ink dot at a position on print media at or adjacent a position where the faulty nozzle would otherwise have printed it.

46. A method of expelling ink from a printhead module including at least one row that comprises a plurality of adjacent sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, the method comprising providing, for each set of nozzles, a fire signal in accordance with the sequence:
[nozzle position 1, nozzle position n, nozzle position 2, nozzle position (n-1), ... , nozzle position x], wherein nozzle position x is at or adjacent the centre of the set of nozzles.

47. A method according to claim 46,wherein the nozzle at each given position within the set is fired simultaneously with the nozzles in the other sets at respective corresponding positions.

48. A method according to claim 46,wherein the printhead module includes a plurality of the rows of nozzles, the method including sequentially repeating the for each of the rows of nozzles.

49. A method according to claim 48, wherein the rows are disposed in pairs.

50. A method according to claim 49, wherein the rows in each pair of rows are offset relative to each other.

51. A method according to claim 50, wherein each pair of rows is configured to print the same color ink.

52. A method according to claim 51, wherein each pair of rows is connected to a common ink source.

53. A method according to claim 46,wherein the sets of nozzles are adjacent each other.

54. A method according to claim 46,wherein the sets of nozzles are separated by an intermediate nozzle, the intermediate nozzle being fired either prior to the nozzle at position I in each set, or following the nozzle at position n.

55. A method according to claim 46,including the step of providing the fire sequence to the printhead module from a printer controller, the fire signals being based on the fire sequence.

56. A method according to claim 55, wherein the fu-e sequence is loaded into a shift register in the printhead module.

57. A method according to claim 46,the method at least partially compensating for errors in ink dot placement by at least one of a plurality of nozzles due to erroneous rotational displacement of a printhead module relative to a carrier, the nozzles being disposed on the printhead module, the method comprising the steps of:
(a). determining the rotational displacement;
(b). determining at least one correction factor that at least partially compensates for the ink dot displacement;
and (c). using the con-ection factor to alter the output of the ink dots to at least partially compensate for the rotational displacement.

58. A method according to claim 46,the method including expelling ink from a printhead module including at least one row that comprises a plurality of sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, the method comprising the steps of:
(a). providing a fire signal to nozzles at a first and nth position in each set of nozzles;
(b). providing a fire signal to the next inward pair of nozzles in each set;
(c). in the event n is an even number, repeating step (b) until all of the nozzles in each set has been fired; and (d). in the event n is an odd number, repeating step (b) until all of the nozzles but a central nozzle in each set have been fired, and then firing the central nozzle.

59. A method according to claim 46,the method including manufacturing a plurality of printhead modules, at least some of which are capable of being combined in pairs to form bilithic pagewidth printheads, the method comprising the step of laying out each of the plurality of printhead modules on a wafer substrate, wherein at least one of the printhead modules is right-handed and at least another is left-handed.

60. A method according to claim 46,the method being performed in conjunction with a printhead module including:

at least one row of print nozzles;
at least two shift registers for shifting in dot data supplied from a data source to each of the at least one rows, wherein each print nozzle obtains dot data to be fired from an element of one of the shift registers.

61. A method.according to claim 46,the method being performed in a printer comprising:
a printhead comprising at least a first elongate printhead module, the at least one printhead module including at least one row of print nozzles for expelling ink; and at least first and second printer controllers configured to receive print data and process the print data to output dot data to the printhead, wherein the first and second printer controllers are connected to a common input of the printhead.

62. A method according to claim 46,the method being performed in a printer comprising:
a printhead comprising first and second elongate printhead modules, the printhead modules being parallel to each other and being disposed end to end on either side of a join region;
at least first and second printer controllers configured to receive print data and process the print data to output dot data to the printhead, wherein the first printer controller outputs dot data only to the first printhead module and the second printer controller outputs dot data only to the second printhead module, wherein the printhead modules are configured such that no dot data passes between them.

63. A method according to claim 46,the method being performed in a printer comprising:
a printhead comprising first and second elongate printhead modules, the printhead modules being parallel to each other and being disposed end to end on either side of a join region, wherein the first printhead module is longer than the second printhead module;
at least first and second printer controllers configured to receive print data and process the print data to output dot data to the printhead, wherein: the first printer controller outputs dot data to both the first printhead module and the second printhead module; and the second printer controller outputs dot data only to the second printhead module.

64. A method according to claim 46,the method being performed in a printer comprising:
a printhead comprising first and second elongate printhead modules, the printhead modules being parallel to each other and being disposed end to end on either side of a join region, wherein the first printhead module is longer than the second printhead module;
at least first and second printer controllers configured to receive print data and process the print data to output dot data for the printhead, wherein: the first printer controller outputs dot data to both the first printhead module and the second controller; and the second printer controller outputs dot data to the second printhead module, wherein the dot data output by the second printer controller includes dot data it generates and at least some of the dot data received from the first printer controller.

65. A method according to claim 46,the method being performed in conjunction with a printer controller for supplying dot data to at least one printhead module and at least partially compensating for errors in ink dot placement by at least one of a plurality of nozzles on the printhead module due to erroneous rotational displacement of the printhead module relative to a carrier, the printer being configured to:
access a correction factor associated with the at least one printhead module;
determine an order in which at least some of the dot data is supplied to at least one of the at least one printhead modules, the order being determined at least partly on the basis of the correction factor, thereby to at least partially compensate for the rotational displacement; and supply the dot data to the printhead module.

66. A method according to claim 46,the method being performed in conjunction with a printer controller for supplying dot data to a printhead module having a plurality of nozzles for expelling ink, the printhead module including a plurality of thermal sensors, each of the thermal sensors being configured to respond to a temperature at or adjacent at least one of the nozzles, the printer controller being configured to modify operation of at least some of the nozzles in response to the temperature rising above a first threshold.

67. A method according to claim 46,the method being performed in conjunction with a printer controller for controlling a printhead comprising at least one monolithic printhead module, the at least one printhead module having a plurality of rows of nozzles configured to extend, in use, across at least part of a printable pagewidth of the printhead, the nozzles in each row being grouped into at least first and second fire groups, the printhead module being configured to sequentially fire, for each row, the nozzles of each fire group, such that each nozzle in the sequence from each fire group is fired simultaneously with respective con-esponding nozzles in the sequence in the other fire groups, wherein the nozzles are fired row by row such that the nozzles of each row are all fired before the nozzles of each subsequent row, wherein the printer controller is configured to provide one or more control signals that control the order of firing of the nozzles.

68. A method according to claim 46,the method being performed in conjunction with a printer controller for outputting to a printhead module:
dot data to be printed with at least two different inks; and control data for controlling printing of the dot data;
the printer controller including at least one communication output, each or the communication output being configured to output at least some of the control data and at least some of the dot data for the at least two inks.

69. A method according to claim 46,the method being performed in conjunction with a printhead module including at least one row of printhead nozzles, at least one row including at least one displaced row portion, the displacement of the row portion including a component in a direction normal to that of a pagewidth to be printed.

70. A method according to claim 46,the method being performed in conjunction with a printer controller for supplying print data to at least one printhead module capable of printing a maximum of n of channels of print data, the at least one printhead module being configurable into:
a first mode, in which the printhead module is configured to receive data for a first number of the channels; and a second mode, in which the printhead module is configured to receive print data for a second number of the channels, wherein the first number is greater than the second number;
wherein the printer controller is selectively configurable to supply dot data for the first and second modes.

71. A method according to claim 46,the method being performed in conjunction with a printer controller for supplying data to a printhead comprising a plurality of printhead modules, the printhead being wider than a reticle step used in forming the modules, the printhead comprising at least two types of the modules, wherein each type is determined by its geometric shape in plan.

72. A method according to claim 46,the method being used in conjunction with a printer controller for supplying one or more control signals to a printhead module, the printhead module including at least one row that comprises a plurality of sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, such that:
providing a fire signal to nozzles at a first and nth position in each set of nozzles;
providing a fire signal to the next inward pair of nozzles in each set;
in the event n is an even number, repeating step (b) until all of the nozzles in each set has been fired; and in the event n is an odd number, repeating step (b) until all of the nozzles but a central nozzle in each set have been fired, and then firing the central nozzle.

73. A method according to claim 46,the method being used in conjunction with a printer controller for supplying one or more control signals to a printhead module, the printhead module including at least one row that comprises a plurality of adjacent sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, the method comprising providing, for each set of nozzles, a fire signal in accordance with the sequence: [nozzle position 1, nozzle position n, nozzle position 2, nozzle position (n-1), ... , nozzle position x], wherein nozzle position x is at or adjacent the centre of the set of nozzles.

74. A method according to claim 46,the method being performed in conjunction with a printer controller for supplying dot data to a printhead module comprising at least first and second rows configured to print ink of a similar type or color, at least some nozzles in the first row being aligned with respective corresponding nozzles in the second row in a direction of intended media travel relative to the printhead, the printhead module being configurable such that the nozzles in the first and second pairs of rows are fired such that some dots output to print media are printed to by nozzles from the first pair of rows and at least some other dots output to print media are printed to by nozzles from the second pair of rows, the printer controller being configurable to supply dot data to the printhead module for printing.

75. A method according to claim 46,the method being performed in conjunction with a printer controller for supplying dot data to at least one printhead module, the at least one printhead module comprising a plurality of rows, each of the rows comprising a plurality of nozzles for ejecting ink, wherein the printhead module includes at least first and second rows configured to print ink of a siniilar type or color, the printer controller being configured to supply the dot data to the at least one printhead module such that, in the event a nozzle in the first row is faulty, a corresponding nozzle in the second row prints an ink dot at a position on print media at or adjacent a position where the faulty nozzle would otherwise have printed it.

76. A method according to claim 46,the method being performed in conjunction with a printer controller for receiving first data and manipulating the first data to produce dot data to be printed, the print controller including at least two serial outputs for supplying the dot data to at least one printhead, wherein each of the serial outputs is configured to supply dot data for at least two channels of the at least one printhead.

77. A method according to claim 46,the method being performed in conjunction with a printhead module including:
at least one row of print nozzles;
at least first and second shift registers for shifting in dot data supplied from a data source, wherein each shift register feeds dot data to a group of nozzles, and wherein each of the groups of the nozzles is interleaved with at least one of the other groups of the nozzles.

78. A method according to claim 46,the method being performed in conjunction with a printhead capable of printing a maximum of n of channels of print data, the printhead being configurable into:
a first mode, in which the printhead is configured to receive print data for a first number of the channels; and a second mode, in which the printhead is configured to receive print data for a second number of the channels, wherein the first number is greater than the second number.

79. A method according to claim 46,the method being performed in conjunction with a printhead comprising a plurality of printhead modules, the printhead being wider than a reticle step used in forming the modules, the printhead comprising at least two types of the modules, wherein each type is determined by its geometric shape in plan.

80. A method according to claim 46,the method being performed in conjunction with a printhead module including at least one row that comprises a plurality of sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, such that, for each set of nozzles, a fire signal is provided in accordance with the sequence: [nozzle position 1, nozzle position n, nozzle position 2, nozzle position (n-1), ... , nozzle position x], wherein nozzle position x is at or adjacent the centre of the set of nozzles.

81. A method according to claim 46,the method being performed in conjunction with a printhead module including at least one row that comprises a plurality of adjacent sets of n adjacent nozzles, each of the nozzles being configured to expel the ink in response to a fire signal, the printhead being configured to output ink from nozzles at a first and nth position in each set of nozzles, and then each next inward pair of nozzles in each set, until:
in the event n is an even number, all of the nozzles in each set has been fired; and in the event n is an odd number, all of the nozzles but a central nozzle in each set have been fired, and then to fire the central nozzle.

82. A method according to claim 46,the method being performed in conjunction with a printhead module for receiving dot data to be printed using at least two different inks and control data for controlling printing of the dot data, the printhead module including a communication input for receiving the dot data for the at least two colors and the control data.

83. A method according to claim 46,the method being performed in conjunction with a printhead module including at least one row of printhead nozzles, at least one row including at least one displaced row portion, the displacement of the row portion including a component in a direction normal to that of a pagewidth to be printed.

84. A method according to claim 46,the method being performed in conjunction with a printhead module having a plurality of rows of nozzles configured to extend, in use, across at least part of a printable pagewidth, the nozzles in each row being grouped into at least first and second fire groups, the printhead module being configured to sequentially fire, for each row, the nozzles of each fire group, such that each nozzle in the sequence from each fire group is fired simultaneously with respective corresponding nozzles in the sequence in the other fire groups, wherein the nozzles are fired row by row such that the nozzles of each row are all fired before the nozzles of each subsequent row.

85. A method according to claim 46,the method being performed in conjunction with a printhead module comprising at least first and second rows configured to print ink of a similar type or color, at least some nozzles in the first row being aligned with respective corresponding nozzles in the second row in a direction of intended media travel relative to the printhead, the printhead module being configurable such that the nozzles in the first and second pairs of rows are fired such that some dots output to print media are printed to by nozzles from the first pair of rows and at least some other dots output to print media are printed to by nozzles from the second pair of rows.

86. A method according to claim 46,the method being performed in conjunction with a printer controller for providing data to a printhead module that includes:
at least one row of print nozzles;
at least first and second shift registers for shifting in dot data supplied from a data source, wherein each shift register feeds dot data to a group of nozzles, and wherein each of the groups of the nozzles is interleaved with at least one of the other groups of the nozzles.

87. A method according to claim 46,the method being performed in conjunction with a printhead module having a plurality of nozzles for expelling ink, the printhead module including a plurality of thermal sensors, each of the thermal sensors being configured to respond to a temperature at or adjacent at least one of the nozzles, the printhead module being configured to modify operation of the nozzles in response to the temperature rising above a first threshold.

88. A method according to claim 46,the method being performed in conjunction with a printhead module comprising a plurality of rows, each of the rows comprising a plurality of nozzles for ejecting ink, wherein the printhead module includes at least first and second rows configured to print ink of a similar type or color, and being configured such that, in the event a nozzle in the first row is faulty, a corresponding nozzle in the second row prints an ink dot at a position on print media at or adjacent a position where the faulty nozzle would otherwise have printed it.

89. A method according to claim 46,wherein the printhead module includes a plurality of the rows, the method including firing each nozzle in each row simultaneously with the nozzle or nozzles at the same position in the other rows.

90. A method according to claim 46,including a plurality of pairs of the rows, each pair of rows including an odd row and an even row, the odd and even rows in each pair being offset from each other in both x and y directions relative to an intended direction of print media movement relative to the printhead, the method including causing firing of at least a plurality of the odd rows prior to firing any of the even rows, or vice versa.

91. A method according to claim 90, wherein all the odd rows are fired before any of the even rows are fired, or vice versa.

92. A method according to claim 90, wherein the odd rows, or the even rows, or both, are fired in a predetermined order.

93. A method according to claim 92, wherein the predetermined order is selectable from a plurality of predetermined available orders.

94. A method according to claim 90, wherein the predetermined order is sequential.

95. A method according to claim 94, wherein the predetermined order can commence at any of a plurality of the rows.

96. A method of expelling ink from a printhead module including at least one row that comprises a plurality of sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, the method comprising the steps of:
(a) providing a fire signal to nozzles at a first and nth position in each set of nozzles;
(b) providing a fire signal to the next inward pair of nozzles in each set;
(c) in the event n is an even number, repeating step (b) until all of the nozzles in each set has been fired; and (d) in the event n is an odd number, repeating step (b) until all of the nozzles but a central nozzle in each set have been fired, and then firing the central nozzle.

97. A method according to claim 96, wherein the printhead module includes a plurality of the rows of nozzles, the method including sequentially repeating steps (a) to (d) for each of the rows of nozzles.

98. A method according to claim 97, wherein the rows are disposed in pairs.

99. A method according to claim 98, wherein the rows in each pair of rows are offset relative to each other.

100. A method according to claim 99, wherein each pair of rows is configured to print the same color ink.

101. A method according to claim 100, wherein each pair of rows is connected to a common ink source.

102. A method according to claim 96, wherein the sets of nozzles are adjacent each other.

103. A method according to claim 96, wherein the sets of nozzles are separated by an intermediate nozzle, the intermediate nozzle being fired either prior to the nozzle at position 1 in each set, or following the nozzle at position n.

104. A method of expelling ink from a printhead module including at least one row that comprises a plurality of adjacent sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, the method comprising providing, for each set of nozzles, a fire signal in accordance with the sequence:
[nozzle position 1, nozzle position n, nozzle position 2, nozzle position (n-1), ... , nozzle position x], wherein nozzle position x is at or adjacent the centre of the set of nozzles.

105. A method according to claim 104, wherein the nozzle at each given position within the set is fired simultaneously with the nozzles in the other sets at respective corresponding positions.

106. A method according to claim 96, the method at least partially compensating for errors in ink dot placement by at least one.of a plurality of nozzles due to erroneous rotational displacement of a printhead module relative to a carrier, the nozzles being disposed on the printhead module, the method comprising the steps of:
(a) determining the rotational displacement;
(b) determining at least one correction factor that at least partially compensates for the ink dot displacement;
and (c) using the correction factor to alter the output of the ink dots to at least partially compensate for the rotational displacement.

107. A method according to claim 96, the method including expelling ink from a printhead module including at least one row that comprises a plurality of adjacent sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, the method comprising providing, for each set of nozzles, a fire signal in accordance with the sequence: [nozzle position 1, nozzle position n, nozzle position 2, nozzle position (n-1), ... , nozzle position x], wherein nozzle position x is at or adjacent the centre of the set of nozzles.

108. A method according to claim 96, the method including manufacturing a plurality of printhead modules, at least some of which are capable of being combined in pairs to form bilithic pagewidth printheads, the method comprising the step of laying out each of the plurality of printhead modules on a wafer substrate, wherein at least one of the printhead modules is right-handed and at least another is left-handed.

109. A method according to claim 96, the method being performed in conjunction with a printhead module including:
(a). at least one row of print nozzles;
(b). at least two shift registers for shifting in dot data supplied from a data source to each of the at least one rows, wherein each print nozzle obtains dot data to be fired from an element of one of the shift registers.

110. A method according to claim 96, the method being performed in a printer comprising:
(a). a printhead comprising at least a first elongate printhead module, the at least one printhead module including at least one row of print nozzles for expelling ink; and (b). at least first and second printer controllers configured to receive print data and process the print data to output dot data to the printhead, wherein the first and second printer controllers are connected to a common input of the printhead.

111. A method according to claim 96, the method being performed in a printer comprising:

(a). a printhead comprising first and second elongate printhead modules, the printhead modules being parallel to each other and being disposed end to end on either side of a join region;
(b). at least first and second printer controllers configured to receive print data and process the print data to output dot data to the printhead, wherein the first printer controller outputs dot data only to the first printhead module and the second printer controller outputs dot data only to the second printhead module, wherein the printhead modules are configured such that no dot data passes between them.

112. A method according to claim 96, the method being performed in a printer comprising:
(a). a printhead comprising first and second elongate printhead modules, the printhead modules being parallel to each other and being disposed end to end on either side of a join region, wherein the first printhead module is longer than the second printhead module;
(b). at least first and second printer controllers configured to receive print data and process the print data to output dot data to the printhead, wherein: the first printer controller outputs dot data to both the first printhead module and the second printhead module; and the second printer controller outputs dot data only to the second printhead module.

113. A method according to claim 96, the method being performed in a printer comprising:
(a). a printhead comprising first and second elongate printhead modules, the printhead modules being parallel to each other and being disposed end to end on either side of a join region, wherein the first printhead module is longer than the second printhead module;
(b). at least first and second printer controllers configured to receive print data and process the print data to output dot data for the printhead, wherein: the first printer controller outputs dot data to both the first printhead module and the second controller; and the second printer controller outputs dot data to the second printhead module, wherein the dot data output by the second printer controller includes dot data it generates and at least some of the dot data received from the first printer controller.

114. A method according to claim 96, the method being performed in conjunction with a printer controller for supplying dot data to at least one printhead module and at least partially compensating for errors in ink dot placement by at least one of a plurality of nozzles on the printhead module due to erroneous rotational displacement of the printhead module relative to a carrier, the printer being configured to:
(a). access a correction factor associated with the at least one printhead module;
(b). determine an order in which at least some of the dot data is supplied to at least one of the at least one printhead modules, the order being determined at least partly on the basis of the correction factor, thereby to at least partially compensate for the rotational displacement; and (c). supply the dot data to the printhead module.

115. A method according to claim 96, the method being performed in conjunction with a printer controller for supplying dot data to a printhead module having a plurality of nozzles for expelling ink, the printhead module including a plurality of thermal sensors, each of the thermal sensors being configured to respond to a temperature at or adjacent at least one of the nozzles, the printer controller being configured to modify operation of at least some of the nozzles in response to the temperature rising above a first threshold.

116. A method according to claim 96, the method being performed in conjunction with a printer controller for controlling a printhead comprising at least one monolithic printhead module, the at least one printhead module having a plurality of rows of nozzles configured to extend, in use, across at least part of a printable pagewidth of the printhead, the nozzles in each row being grouped into at least first and second fire groups, the printhead module being configured to sequentially fire, for each row, the nozzles of each fire group, such that each nozzle in the sequence from each fire group is fired simultaneously with respective corresponding nozzles in the sequence in the other fire groups, wherein the nozzles are fired row by row such that the nozzles of each row are all fired before the nozzles of each subsequent row, wherein the printer controller is configured to provide one or more control signals that control the order of firing of the nozzles.

117. A method according to claim 96, the method being performed in conjunction with a printer controller for outputting to a printhead module:
(a). dot data to be printed with at least two different inks; and (b). control data for controlling printing of the dot data;
(c). the printer controller including at least one communication output, each or the communication output being configured to output at least some of the control data and at least some of the dot data for the at least two inks.

118. A method according to claim 96, the method being performed in conjunction with a printhead module including at least one row of printhead nozzles, at least one row including at least one displaced row portion, the displacement of the row portion including a component in a direction normal to that of a pagewidth to be printed.

119. A method according to claim 96, the method being performed in conjunction with a printer controller for supplying print data to at least one printhead module capable of printing a maximum of n of channels of print data, the at least one printhead module being configurable into:
(a). a first mode, in which the printhead module is configured to receive data for a first number of the channels; and (b). a second mode, in which the printhead module is configured to receive print data for a second number of the channels, wherein the first number is greater than the second number;
(c). wherein the printer controller is selectively configurable to supply dot data for the first and second modes.

120. A method according to claim 96, the method being performed in conjunction with a printer controller for supplying data to a printhead comprising a plurality of printhead modules, the printhead being wider than a reticle step used in forming the modules, the printhead comprising at least two types of the modules, wherein each type is determined by its geometric shape in plan.

121. A method according to claim 96, the method being used in conjunction with a printer controller for supplying one or more control signals to a printhead module, the printhead module including at least one row that comprises a plurality of sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, such that:
(d) providing a fire signal to nozzles at a first and nth position in each set of nozzles;
(e) providing a fire signal to the next inward pair of nozzles in each set;
(f) in the event n is an even number, repeating step (b) until all of the nozzles in each set has been fired; and (g) in the event n is an odd number, repeating step (b) until all of the nozzles but a central nozzle in each set have been fired, and then firing the central nozzle.

122. A method according to claim 96, the method being,used in conjunction with a printer controller for supplying one or more control signals to a printhead module, the printhead module including at least one row that comprises a plurality of adjacent sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, the method comprising providing, for each set of nozzles, a fire signal in accordance with the sequence: [nozzle position 1, nozzle position n, nozzle position 2, nozzle position (n-1), ... , nozzle position x], wherein nozzle position x is at or adjacent the centre of the set of nozzles.

123. A method according to claim 96, the method being performed in conjunction with a printer controller for supplying dot data to a printhead module comprising at least first and second rows configured to print ink of a similar type or color, at least some nozzles in the first row being aligned with respective corresponding nozzles in the second row in a direction of intended media travel relative to the printhead, the printhead module being configurable such that the nozzles in the first and second pairs of rows are fired such that some dots output to print media are printed to by nozzles from the first pair of rows and at least some other dots output to print media are printed to by nozzles from the second pair of rows, the printer controller being configurable to supply dot data to the printhead module for printing.

124. A method according to claim 96, the method being performed in conjunction with a printer controller for supplying dot data to at least one printhead module, the at least one printhead module comprising a plurality of rows, each of the rows comprising a plurality of nozzles for ejecting ink, wherein the printhead module includes at least first and second rows configured to print ink of a similar type or color, the printer controller being configured to supply the dot data to the at least one printhead module such that, in the event a nozzle in the first row is faulty, a corresponding nozzle in the second row prints an ink dot at a position on print media at or adjacent a position where the faulty nozzle would otherwise have printed it.

125. A method according to claim 96, the method being performed in conjunction with a printer controller for receiving first data and manipulating the first data to produce dot data to be printed, the print controller including at least two serial outputs for supplying the dot data to at least one printhead, wherein each of the serial outputs is configured to supply dot data for at least two channels of the at least one printhead.

126. A method according to claim 96, the method being performed in conjunction with a printhead module including:
(a). at least one row of print nozzles;
(b). at least first and second shift registers for shifting in dot data supplied from a data source, wherein each shift register feeds dot data to a group of nozzles, and wherein each of the groups of the nozzles is interleaved with at least one of the other groups of the nozzles.

127. A method according to claim 96, the method being performed in conjunction with a printhead capable of printing a maximum of n of channels of print data, the printhead being configurable into:
(a). a first mode, in which the printhead is configured to receive print data for a first number of the channels;
and (b). a second mode, in which the printhead is configured to receive print data for a second number of the channels, wherein the first number is greater than the second number.

128. A method according to claim 96, the method being performed in conjunction with a printhead comprising a plurality of printhead modules, the printhead being wider than a reticle step used in forming the modules, the printhead comprising at least two types of the modules, wherein each type is determined by its geometric shape in plan.

129. A method according to claim 96, the method being performed in conjunction with a printhead module including at least one row that comprises a plurality of sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, such that, for each set of nozzles, a fire signal is provided in accordance with the sequence: [nozzle position 1, nozzle position n, nozzle position 2, nozzle position (n-1), ... , nozzle position x], wherein nozzle position x is at or adjacent the centre of the set of nozzles.

130. A method according to claim 96, the method being performed in conjunction with a printhead module including at least one row that comprises a plurality of adjacent sets of n adjacent nozzles, each of the nozzles being configured to expel the ink in response to a fire signal, the printhead being configured to output ink from nozzles at a first and nth position in each set of nozzles, and then each next inward pair of nozzles in each set, until:
(a). in the event n is an even number, all of the nozzles in each set has been fired; and (b). in the event n is an odd number, all of the nozzles but a central nozzle in each set have been fired, and then to fire the central nozzle.

131. A method according to claim 96, the method being performed in conjunction with a printhead module for receiving dot data to be printed using at least two different inks and control data for controlling printing of the dot data, the printhead module including a communication input for receiving the dot data for the at least two colors and the control data.

132. A method according to claim 96, the method being performed in conjunction with a printhead module including at least one row of printhead nozzles, at least one row including at least one displaced row portion, the displacement of the row portion including a component in a direction normal to that of a pagewidth to be printed.

133. A method according to claim 96, the method being performed in conjunction with a printhead module having a plurality of rows of nozzles configured to extend, in use, across at least part of a printable pagewidth, the nozzles in each row being grouped into at least first and second fire groups, the printhead module being configured to sequentially fire, for each row, the nozzles of each fire group, such that each nozzle in the sequence from each fire group is fired simultaneously with respective corresponding nozzles in the sequence in the other fire groups, wherein the nozzles are fired row by row such that the nozzles of each row are all fired before the nozzles of each subsequent row.

134. A method according to claim 96, the method being performed in conjunction with a printhead module comprising at least first and second rows configured to print ink of a similar type or color, at least some nozzles in the first row being aligned with respective corresponding nozzles in the.second row in a direction of intended media travel relative to the printhead, the printhead module being configurable such that the nozzles in the first and second pairs of rows are fired such that some dots output to print media are printed to by nozzles from the first pair of rows and at least some other dots output to print media are printed to by nozzles from the second pair of rows.

135. A method according to claim 96, the method being performed in conjunction with a printer controller for providing data to a printhead module that includes:
a). at least one row of print nozzles;
b). at least first and second shift registers for shifting in dot data supplied from a data source, wherein each shift register feeds dot data to a group of nozzles, and wherein each of the groups of the nozzles is interleaved with at least one of the other groups of the nozzles.

136. A method according to claim 96, the method being performed in conjunction with a printhead module having a plurality of nozzles for expelling ink, the printhead module including a plurality of thermal sensors, each of the thermal sensors being configured to respond to a temperature at or adjacent at least one of the nozzles, the printhead module being configured to modify operation of the nozzles in response to the temperature rising above a first threshold.

137. A method according to claim 96, the method being performed in conjunction with a printhead module comprising a plurality of rows, each of the rows comprising a plurality of nozzles for ejecting ink, wherein the printhead module includes at least first and second rows configured to print ink of a. similar type or color, and being configured such that, in the event a nozzle in the first row is faulty, a corresponding nozzle in the second row prints an ink dot at a position on print media at or adjacent a position where the faulty nozzle would otherwise have printed it.

138. A method according to claim 96, wherein the printhead module includes a plurality of the rows, the method including firing each nozzle in each row simultaneously with the nozzle or nozzles at the same position in the other rows.

139. A method according to claim 96, wherein the printhead module includes a plurality of the rows, the method including firing each nozzle in each row simultaneously with the nozzle or nozzles at the same position in the other rows.

140. A method according to claim 96, including a plurality of pairs of the rows, each pair of rows including an odd row and an even row, the odd and even rows in each pair being offset from each other in both x and y directions relative to. an intended direction of print media movement relative to the printhead, the method including causing firing of at least a plurality of the odd rows prior to firing any of the even rows, or vice versa.

141. A method according to claim 140, wherein all the odd rows are fired before any of the even rows are fired, or vice versa.

142. A method according to claim 140, wherein the odd rows, or the even rows, or both, are fired in a predetermined order.

143. A method according to claim 142, wherein the predetermined order is selectable from a plurality of predetermined available orders.

144. A method according to claim 140, wherein the predetermined order is sequential.

145. A method according to claim 144, wherein the predetermined order can commence at any of a plurality of the rows.

146. A method of manufacturing a plurality of printhead modules, at least some of which are capable of being combined in pairs to form bilithic pagewidth printheads, the method comprising the step of laying out each of the plurality of printhead modules on a wafer substrate, wherein at least one of the printhead modules is right-handed and at least another is left-handed.

147. A method of manufacturing a plurality of pagewidth printheads, the method comprising the steps of:
manufacturing a plurality of printhead modules in accordance with claim 1; and assembling pairs of at least some of the printhead modules to form pagewidth printheads, wherein each of the printhead modules in each pagewidth printhead is shorter than the pagewidth.

148. A method according to claim 147, wherein the printhead modules of at least one of the pagewidth printheads are of relatively different lengths.

149. A method according to claim 147, wherein the printhead modules of at least one of the pagewidth printheads are of the same length.

150. A method according to claim 147, wherein the printhead modules of at least one of the pagewidth printheads are of relatively different lengths, and the printhead modules of at least another of the pagewidth printheads are of the same length.

151. A method according to claim 147, wherein at least some of the printhead modules are larger than a reticle step used in laying out those printhead modules.

152. A method according to claim 146, including the step of laying out a plurality of left-handed and right-handed printhead modules.

153. A method according to claim 152, including the step of laying out a plurality of different lengths of left-handed and right-handed printhead modules.

154. A method according to claim 146, the method at least partially compensating for errors in ink dot placement by at least one of a plurality of nozzles due to erroneous rotational displacement of a printhead module relative to a carrier, the nozzles being disposed on the printhead module, the method comprising the steps of:
(a). determining the rotational displacement;

(b). determining at least one correction factor that at least partially compensates for the ink dot displacement;
and (c). using the correction factor to alter the output of the ink dots to at least partially compensate for the rotational displacement.

155. A method according to claim 146, the method including expelling ink from a printhead module including at least one row that comprises a plurality of adjacent sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, the method comprising providing, for each set of nozzles, a fire signal in accordance with the sequence: [nozzle position 1, nozzle position n, nozzle position 2, nozzle position (n-1), ... , nozzle position x], wherein nozzle position x is at or adjacent the centre of the set of nozzles.

156. A method according to claim 146, the method including expelling ink from a printhead module including at least one row that comprises a plurality of sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, the method comprising the steps of:
(a). providing a fire signal to nozzles at a first and nth position in each set of nozzles;
(b). providing a fire signal to the next inward pair of nozzles in each set;
(c). in the event n is an even number, repeating step (b) until all of the nozzles in each set has been fired; and (d). in the event n is an odd number, repeating step (b) until all of the nozzles but a central nozzle in each set have been fired, and then firing the central nozzle.

157. A method according to claim 146, the method being performed in conjunction with a printhead module including:
at least one row of print nozzles;
at least two shift registers for shifting in dot data supplied from a data source to each of the at least one rows, wherein each print nozzle obtains dot data to be fired from an element of one of the shift registers.

158. A method according to claim 146, the method being performed in a printer comprising:
a printhead comprising at least a first elongate printhead module, the at least one printhead module including at least one row of print nozzles for expelling ink; and at least first and second printer controllers configured to receive print data and process the print data to output dot data to the printhead, wherein the first and second printer controllers are connected to a common input of the printhead.

159. A met hod according to claim 146, the method being performed in a printer comprising:
a printhead comprising first and second elongate printhead modules, the printhead modules being parallel to each other and being disposed end to end on either side of a join region;

at least first and second printer controllers configured to receive print data and process the print data to output dot data to the printhead, wherein the first printer controller outputs dot data only to the first printhead module and the second printer controller outputs dot data only to the second printhead module, wherein the printhead modules are configured such that no dot data passes between them.

160. A method according to claim 146, the method being performed in a printer comprising:
a printhead comprising first and second elongate printhead modules, the printhead modules being parallel to each other and being disposed end to end on either side of a join region, wherein the first printhead module is longer than the second printhead module;
at least first and second printer controllers configured to receive print data and process the print data to output dot data to the printhead, wherein: the first printer controller outputs dot data to both the first printhead module and the second printhead module; and the second printer controller outputs dot data only to the second printhead module.

161. A method according to claim 146, the method being performed in a printer comprising:
a printhead comprising first and second elongate printhead modules, the printhead modules being parallel to each other and being disposed end to end on either side of a join region, wherein the first printhead module is longer than the second printhead module;
at least first and second printer controllers configured to receive print data and process the print data to output dot data for the printhead, wherein: the first printer controller outputs dot data to both the first printhead module and the second controller, and the second printer controller outputs dot data to the second printhead module, wherein the dot data output by the second printer controller includes dot data it generates and at least some of the dot data received from the first printer controller.

162. A method according to claim 146, the method being performed in conjunction with a printer controller for supplying dot data to at least one printhead module and at least partially compensating for errors in ink dot placement by at least one of a plurality of nozzles on the printhead module due to erroneous rotational displacement of the printhead module relative to a carrier, the printer being configured to:
access a correction factor associated with the at least one printhead module;
determine an order in which at least some of the dot data is supplied to at least one of the at least one printhead modules, the order being determined at least partly on the basis of the correction factor, thereby to at least partially compensate for the rotational displacement; and supply the dot data to the printhead module.

163. A method according to claim 146, the method being performed in conjunction with a printer controller for supplying dot data to a printhead module having a plurality of nozzles for expelling ink, the printhead module including a plurality of thermal sensors, each of the thermal sensors being configured to respond to a temperature at or adjacent at least one of the nozzles, the printer controller being configured to modify operation of at least some of the nozzles in response to the temperature rising above a first threshold.

164. A method according to claim 146, the method being performed in conjunction with a printer controller for controlling a printhead comprising at least one monolithic printhead module, the at least one printhead module having a plurality of rows of nozzles configured to extend, in use, across at least part of a printable pagewidth of the printhead, the nozzles in each row being grouped into at least first and second fire groups, the printhead module being configured to sequentially fire, for each row, the nozzles of each fire group, such that each nozzle in the sequence from each fire group is fired simultaneously with respective corresponding nozzles in the sequence in the other fire groups, wherein the nozzles are fired row by row such that the nozzles of each row are all fired before the nozzles of each subsequent row, wherein the printer controller is configured to provide one or more control signals that control the order of firing of the nozzles.

165. A method according to claim 146, the method being performed in conjunction with a printer controller for outputting to a printhead module:
dot data to be printed with at least two different inks; and control data for controlling printing of the dot data;
the printer controller including at least one communication output, each or the communication output being configured to output at least some of the control data and at least some of the dot data for the at least two inks.

166. A method according to claim 146, the method being performed in conjunction with a printhead module including at least one row of printhead nozzles, at least one row including at least one displaced row portion, the displacement of the row portion including a component in a direction normal to that of a pagewidth to be printed.

167. A method according to claim 146, the method being performed in conjunction with a printer controller for supplying print data to at least one printhead module capable of printing a maximum of n of channels of print data, the at least one printhead module being configurable into:
a first mode, in which the printhead module is configured to receive data for a first number of the channels; and a second mode, in which the printhead module is configured to receive print data for a second number of the channels, wherein the first number is greater than the second number;
wherein the printer controller is selectively configurable to supply dot data for the first and second modes.

168. A method according to claim 146, the method being performed in conjunction with a printer controller for supplying data to a printhead comprising a plurality of printhead modules, the printhead being wider than a reticle step used in forming the modules, the printhead comprising at least two types of the modules, wherein each type is determined by its geometric shape in plan.

169. A method according to claim 146, the method being used in conjunction with a printer controller for supplying one or more control signals to a printhead module, the printhead module including at least one row that comprises a plurality of sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, such that:
(a). providing a fire signal to nozzles at a first and nth position in each set of nozzles;
(b). providing a fire signal to the next inward pair of nozzles in each set;
(c). in the event n is an even number, repeating step (b) until all of the nozzles in each set has been fired; and (d). in the event n is an odd number, repeating step (b) until all of the nozzles but a central nozzle in each set have been fired, and then firing the central nozzle.

170. A method according to claim 146, the method being used in conjunction with a printer controller for supplying one or more control signals to a printhead module, the printhead module including at least one row that comprises a plurality of adjacent sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, the method comprising providing, for each set of nozzles, a fire signal in accordance with the sequence: [nozzle position 1, nozzle position n, nozzle position 2, nozzle position (n-1), ... , nozzle position x], wherein nozzle position x is at or adjacent the centre of the set of nozzles.

171. A method according to claim 146, the method being performed in conjunction with a printer controller for supplying dot data to a printhead module comprising at least first and second rows configured to print ink of a similar type or color, at least some nozzles in the first row being aligned with respective corresponding nozzles in the second row in a direction of intended media travel relative to the printhead, the printhead module being configurable such that the nozzles in the first and second pairs of rows are fired such that some dots output to print media are printed to by nozzles from the first pair of rows and at least some other dots output to print media are printed to by nozzles from the second pair of rows, the printer controller being configurable to supply dot data to the printhead module for printing.

172. A method according to claim 146, the method being performed in conjunction with a printer controller for supplying dot data to at least one printhead module, the at least one printhead module comprising a plurality of rows, each of the rows comprising a plurality of nozzles for ejecting ink, wherein the printhead module includes at least first and second rows configured to print ink of a similar type or color, the printer controller being configured to supply the dot data to the at least one printhead module such that, in the event a nozzle in the first row is faulty, a corresponding nozzle in the second row prints an ink dot at a position on print media at or adjacent a position where the faulty nozzle would otherwise have printed it.

173. A.method according to claim 146, the method being performed in conjunction with a printer controller for receiving first data and manipulating the first data to produce dot data to be printed, the print controller including at least two serial outputs for supplying the dot data to at least one printhead, wherein each of the serial outputs is configured to supply dot data for at least two channels of the at least one printhead.

174. A method according to claim 146, the method being performed in conjunction with a printhead module including:
at least one row of print nozzles;
at least first and second shift registers for shifting in dot data supplied from a data source, wherein each shift register feeds dot data to a group of nozzles, and wherein each of the groups of the nozzles is interleaved with at least one of the other groups of the nozzles.

175. A method according to claim 146, the method being performed in conjunction with a printhead capable of printing a maximum of n of channels of print data, the printhead being configurable into:
a first mode, in which the printhead is configured to receive print data for a first number of the channels; and a second mode, in which the printhead is configured to receive print data for a second number of the channels, wherein the first number is greater than the second number.

176. A method according to claim 146, the method being performed in conjunction with a printhead comprising a plurality of printhead modules, the printhead being wider than a reticle step used in forming the modules, the printhead comprising at least two types of the modules, wherein each type is determined by its geometric shape in plan.

177. A method according to claim 146, the method being performed in conjunction with a printhead module including at least one row that comprises a plurality of sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, such that, for each set of nozzles, a fire signal is provided in accordance with the sequence: [nozzle position 1, nozzle position n, nozzle position 2, nozzle position (n-1), ... , nozzle position x], wherein nozzle position x is at or adjacent the centre of the set of nozzles.

178. A method according to claim 146, the method being performed in conjunction with a printhead module including at least one row that comprises a plurality of adjacent sets of n adjacent nozzles, each of the nozzles being configured to expel the ink in response to a fire signal, the printhead being configured to output ink from nozzles at a first and nth position in each set of nozzles, and then each next inward pair of nozzles in each set, until:
in the event n is an even number, all of the nozzles in each set has been fired; and in the event n is an odd number, all of the nozzles but a central nozzle in each set have been fired, and then to fire the central nozzle.

179. A method according to claim 146, the method being performed in conjunction with a printhead module for receiving dot data to be printed using at least two different inks and control data for controlling printing of the dot data, the printhead module including a communication input for receiving the dot data for the at least two colors and the control data.

180. A method according to claim 146, the method being performed in conjunction with a printhead module including at least one row of printhead nozzles, at least one row including at least one displaced row portion, the displacement of the row portion including a component in a direction normal to that of a pagewidth to be printed.

181. A method according to claim 146, the method being performed in conjunction with a printhead module having a plurality of rows of nozzles configured to extend, in use, across at least part of a printable pagewidth, the nozzles in each row being grouped into at least first and second fire groups, the printhead module being configured to sequentially fire, for each row, the nozzles of each fire group, such that each nozzle in the sequence from each fire group is fired simultaneously with respective corresponding nozzles in the sequence in the other fire groups, wherein the nozzles are fired row by row such that the nozzles of each row are all fired before the nozzles of each subsequent row.

182. A method according to claim 146, the method being performed in conjunction with a printhead module comprising at least first and second rows configured to print ink of a similar type or color, at least some nozzles in the first row being aligned with respective corresponding nozzles in the second row in a direction of intended media travel relative to the printhead, the printhead module being configurable such that the nozzles in the first and second pairs of rows are fired such that some dots output to print media are printed to by nozzles from the first pair of rows and at least some other dots output to print media are printed to by nozzles from the second pair of rows.

183. A method according to claim 146, the method being performed in conjunction with a printer controller for providing data to a printhead module that includes:
at least one row of print nozzles;
at least first and second shift registers for shifting in dot data supplied from a data source, wherein each shift register feeds dot data to a group of nozzles, and wherein each of the groups of the nozzles is interleaved with at least one of the other groups of the nozzles.

184. A method according to claim 146, the method being performed in conjunction with a printhead module having a plurality of nozzles for expelling ink, the printhead module including a plurality of thermal sensors, each of the thermal sensors being configured to respond to a temperature at or adjacent at least one of the nozzles, the printhead module being configured to modify operation of the nozzles in response to the temperature rising above a first threshold.

185. A method according to claim 146, the method being performed in conjunction with a printhead module comprising a plurality of rows, each of the rows comprising a plurality of nozzles for ejecting ink, wherein the printhead module includes at least first and second rows configured to print ink of a similar type or color, and being configured such that, in the event a nozzle in the first row is faulty, a corresponding nozzle in the second row prints an ink dot at a position on print media at or adjacent a position where the faulty nozzle would otherwise have printed it.

186. A printhead module including:
at least one row of print nozzles;
at least two shift registers for shifting in dot data supplied from a data source to each of the at least one rows, wherein each print nozzle obtains dot data to be fired from an element of one of the shift registers.

187. A printhead module according to claim 186, wherein there is a one to one correspondence between the nozzles and elements of the two shift registers.

188. A printhead module according to claim 187, wherein each of the shift registers supplies dot data to about half of the nozzles.

189. A printhead module according to claim 186, including at least one pair of rows of the nozzles, the rows in each pair being offset with respect to each other by half the intra-row nozzle spacing.

190. A printhead module according to claim 189, wherein each of the at least two shift registers supplies dot data to at least some of the nozzles in at least one pair of rows.

191. A printhead comprising a plurality of printhead modules according to claim 186.

192. A printhead according to claim 191, wherein the printhead is a pagewidth printhead.

193. A printhead module according to claim 186, configured to receive dot data to which a method of at least partially compensating for errors in ink dot placement by at least one of a plurality of nozzles due to erroneous rotational displacement of a printhead module relative to a carrier has been applied, the nozzles being disposed on the printhead module, the method comprising the steps of:
(a). determining the rotational displacement;
(b). determining at least one correction factor that at least partially compensates for the ink dot displacement;
and (c). using the correction factor to alter the output of the ink dots to at least partially compensate for the rotational displacement.

194. A printhead module according to claim 186, configured to receive dot data to which a method of expelling ink has been applied, the method being applied to a printhead module including at least one row that comprises a plurality of adjacent sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, the method comprising providing, for each set of nozzles, a fire signal in accordance with the sequence: [nozzle position 1, nozzle position n, nozzle position 2, nozzle position (n-1), ... , nozzle position x], wherein nozzle position x is at or adjacent the centre of the set of nozzles.

195. A printhead module according to claim 186, configured to receive dot data to which a method of expelling ink has been applied, the method being applied to a printhead module including at least one row that comprises a plurality of sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, the method comprising the steps of:
(a). providing a fire signal to nozzles at a first and nth position in each set of nozzles;
(b). providing a fire signal to the next inward pair of nozzles in each set;
(c). in the event n is an even number, repeating step (b) until all of the nozzles in each set has been fired; and (d). in the event n is an odd number, repeating step (b) until all of the nozzles but a central nozzle in each set have been fired, and then firing the central nozzle.

196. A printhead module according to claim 186, having been manufactured in accordance with a method of manufacturing a plurality of printhead modules, at least some of which are capable of being combined in pairs to form bilithic pagewidth printheads, the method comprising the step of laying out each of the plurality of printhead modules on a wafer substrate, wherein at least one of the printhead modules is right-handed and at least another is left-handed.

197. A printhead module according to claim 186, including:
at least one row of print nozzles;
at least two shift registers for shifting in dot data supplied from a data source to each of the at least one rows, wherein each print nozzle obtains dot data to be fired from an element of one of the shift registers.

198. A printhead module according to claim 186, installed in a printer comprising:
a printhead comprising at least the first elongate printhead module, the at least one printhead module including at least one row of print nozzles for expelling ink; and at least first and second printer controllers configured to receive print data and process the print data to output dot data to the printhead, wherein the first and second printer controllers are connected to a common input of the printhead.

199. A printhead module according to claim 186, installed in a printer comprising:
a printhead comprising first and second elongate printhead modules, the printhead modules being parallel to each other and being disposed end to end on either side of a join region;
at least first and second printer controllers configured to receive print data and process the print data to output dot data to the printhead, wherein the first printer controller outputs dot data only to the first printhead module and the second printer controller outputs dot data only to the second printhead module, wherein the printhead modules are configured such that no dot data passes between them.

200. A printhead module according to claim 186, installed in a printer comprising:
a printhead comprising first and second elongate printhead modules, the printhead modules being parallel to each other and being disposed end to end on either side of a join region, wherein the first printhead module is longer than the second printhead module;
at least first and second printer controllers configured to receive print data and process the print data to output dot data to the printhead, wherein: the first printer controller outputs dot data to both the first printhead module and the second printhead module; and the second printer controller outputs dot data only to the second printhead module.

201. A printhead module according to claim 186, installed in a printer comprising:
a printhead comprising first and second elongate printhead modules, the printhead modules being parallel to each other and being disposed end to end on either side of a join region, wherein the first printhead module is longer than the second printhead module;
at least first and second printer controllers configured to receive print data and process the print data to output dot data for the printhead, wherein: the first printer controller outputs dot data to both the first printhead module and the second controller; and the second printer controller outputs dot data to the second printhead module, wherein the dot data output by the second printer controller includes dot data it generates and at least some of the dot data received from the first printer controller.

202. A printhead module according to claim 186, in communication with a printer controller for supplying dot data to at least one printhead module and at least partially compensating for errors in ink dot placement by at least one of a plurality of nozzles on the printhead module due to erroneous rotational displacement of the printhead module relative to a carrier, the printer being configured to:
access a correction factor associated with the at.least one printhead module;
determine an order in which at least some of the dot data is supplied to at least one of the at least one printhead modules, the order being determined at least partly on the basis of the correction factor, thereby to at least partially compensate for the rotational displacement; and supply the dot data to the printhead module.

203. A printhead module according to claim 186, in communication with a printer controller for supplying dot data to a printhead module having a plurality of nozzles for expelling ink, the printhead module including a plurality of thermal sensors, each of the thermal sensors being configured to respond to a temperature at or adjacent at least one of the nozzles, the printer controller being configured to modify operation of at least some of the nozzles in response to the temperature rising above a first threshold.

204. A printhead module according to claim 186, in communication with a printer controller for controlling a printhead comprising at least one monolithic printhead module, the at least one printhead module having a plurality of rows of nozzles configured to extend, in use, across at least part of a printable pagewidth of the printhead, the nozzles in each row being grouped into at least first and second fire groups, the printhead module being configured to sequentially fire, for each row, the nozzles of each fire group, such that each nozzle in the sequence from each fire group is fired simultaneously with respective corresponding nozzles in the sequence in the other fire groups, wherein the nozzles are fired row by row such that the nozzles of each row are all fired before the nozzles of each subsequent row, wherein the printer controller is configured to provide one or more control signals that control the order of firing of the nozzles.

205. A printhead module according to claim 186, in communication with a printer controller for outputting to a printhead module:
dot data to be printed with at least two different inks; and control data for controlling printing of the dot data;
the printer controller including at least one communication output, each or the communication output being configured to output at least some of the control data and at least some of the dot data for the at least two inks.

206. A printhead module according to claim 186, including at least one row of printhead nozzles, at least one row including at least one displaced row portion, the displacement of the row portion including a component in a direction normal to that of a pagewidth to be printed.

207. A printhead module according to claim 186, in communication with a printer controller for supplying print data to at least one printhead module capable of printing a maximum of n of channels of print data, the at least one printhead module being configurable into:
a first mode, in which the printhead module is configured to receive data for a first number of the channels; and a second mode, in which the printhead module is configured to receive print data for a second number of the channels, wherein the first number is greater than the second number;
wherein the printer controller is selectively configurable to supply dot data for the first and second modes.

208. A printhead module according to claim 186, in communication with a printer controller for supplying data to a printhead comprising a plurality of printhead modules, the printhead being wider than a reticle step used in forming the modules, the printhead comprising at least two types of the modules, wherein each type is determined by its geometric shape in plan.

209. A printhead module according to claim 186, used in conjunction with a printer controller for supplying one or more control signals to a printhead module, the printhead module including at least one row that comprises a plurality of sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, such that:
(a). a fire signal is provided to nozzles at a first and nth position in each set of nozzles;
(b). a fire signal is provided to the next inward pair of nozzles in each set;
(c). in the event n is an even number, step (b) is repeated until all of the nozzles in each set has been fired;
and (d). in the event n is an odd number, step (b) is repeated until all of the nozzles but a central nozzle in each set have been fired, and then the central nozzle is fired.

210. A printhead module according to claim 186, used in conjunction with a printer controller for supplying one or more control signals to a printhead module, the printhead module including at least one row that comprises a plurality of adjacent sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, the method comprising providing, for each set of nozzles, a fire signal in accordance with the sequence: [nozzle position 1, nozzle position n, nozzle position 2, nozzle position (n-1), ... , nozzle position x], wherein nozzle position x is at or adjacent the centre of the set of nozzles.

211. A printhead module according to claim 186, in communication with a printer controller for supplying dot data to a printhead module comprising at least first and second rows configured to print ink of a similar type or color, at least some nozzles in the first row being aligned with respective corresponding nozzles in the second row in a direction of intended media travel relative to the printhead, the printhead module being configurable such that the nozzles in the first and second pairs of rows are fired such that some dots output to print media are printed to by nozzles from the first pair of rows and at least some other dots output to print media are printed to by nozzles from the second pair of rows, the printer controller being configurable to supply dot data to the printhead module for printing.

212. A printhead module according to claim 186, in communication with a printer controller for supplying dot data to at least one printhead module, the at least one printhead module comprising a plurality of rows, each of the rows comprising a plurality of nozzles for ejecting ink, wherein the printhead module includes at least first and second rows configured to print ink of a similar type or color, the printer controller being configured to supply the dot data to the at least one printhead module such that, in the event a nozzle in the first row is faulty, a corresponding nozzle in the second row prints an ink dot at a position on print media at or adjacent a position where the faulty nozzle would otherwise have printed it.

213. A printhead module according to claim 186, in communication with a printer controller for receiving first data and manipulating the first data to produce dot data to be printed, the print controller including at least two serial outputs for supplying the dot data to at least one printhead.

214. A printhead module according to claim 186, including:
at least one row of print nozzles;
at least first and second shift registers for shifting in dot data supplied from a data source, wherein each shift register feeds dot data to a group of nozzles, and wherein each of the groups of the nozzles is interleaved with at least one of the other groups of the nozzles.

215. A printhead module according to claim 186 being capable of printing a maximum of n of channels of print data, the printhead being configurable into:
a first mode, in which the printhead is configured to receive print data for a first number of the channels; and a second mode, in which the printhead is configured to receive print data for a second number of the channels, wherein the first number is greater than the second number.

216. A printhead comprising a plurality of printhead modules according to claim 186, the printhead being wider than a reticle step used in forming the modules, the printhead comprising at least two types of the modules, wherein each type is determined by its geometric shape in plan.

217. A printhead module according to claim 186, including at least one row that comprises a plurality of sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, such that, for each set of nozzles, a fire signal is provided in accordance with the sequence: [nozzle position 1, nozzle position n, nozzle position 2, nozzle position (n-1), ... , nozzle position x], wherein nozzle position x is at or adjacent the centre of the set of nozzles.

218. A printhead module according to claim 186, including at least one row that comprises a plurality of adjacent sets of n adjacent nozzles, each of the nozzles being configured to expel the ink in response to a fire signal, the printhead being configured to output ink from nozzles at a first and nth position in each set of nozzles, and then each next inward pair of nozzles in each set, until:
in the event n is an even number, all of the nozzles in each set has been fired; and in the event n is an odd number, all of the nozzles but a central nozzle in each set have been fired, and then to fire the central nozzle.

219. A printhead module according to claim 186, for receiving dot data to be printed using at least two different inks and control data for controlling printing of the dot data, the printhead module including a communication input for receiving the dot data for the at least two colors and the control data.

220. A printhead module according to claim 186, including at least one row of printhead nozzles, at least one row including at least one displaced row portion, the displacement of the row portion including a component in a direction normal to that of a pagewidth to be printed.

221. A printhead module according to claim 186, having a plurality of rows of nozzles configured to extend, in use, across at least part of a printable pagewidth, the nozzles in each row being grouped into at least first and second fire groups, the printhead module being configured to sequentially fire, for each row, the nozzles of each fire group, such that each nozzle in the sequence from each fire group is fired simultaneously with respective corresponding nozzles in the sequence in the other fire groups, wherein the nozzles are fired row by row such that the nozzles of each row are all fired before the nozzles of each subsequent row.

222. A printhead module according to claim 186, comprising at least first and second rows configured to print ink of a similar type or color, at least some nozzles in the first row being aligned with respective corresponding nozzles in the second row in a direction of intended media travel relative to the printhead, the printhead module being configurable such that the nozzles in the first and second pairs of rows are fired such that some dots output to print media are printed to by nozzles from the first pair of rows and at least some other dots output to print media are printed to by nozzles from the second pair of rows.

223. A printhead module according to claim 186, in communication with a printer controller for providing data to a printhead module that includes:
at least one row of print nozzles;
at least first and second shift registers for shifting in dot data supplied from a data source, wherein each shift register feeds dot data to a group of nozzles, and wherein each of the groups of the nozzles is interleaved with at least one of the other groups of the nozzles.

224. A printhead module according to claim 186, having a plurality of nozzles for expelling ink, the printhead module including a plurality of thermal sensors, each of the thermal sensors being configured to respond to a temperature at or adjacent at least one of the nozzles, the printhead module being configured to modify operation of the nozzles in response to the temperature rising above a first threshold.

225. A printhead module according to claim 186, comprising a plurality of rows, each of the rows comprising a plurality of nozzles for ejecting ink, wherein the printhead module includes at least first and second rows configured to print ink of a similar type or color, and being configured such that, in the event a nozzle in the first row is faulty, a corresponding nozzle in the second row prints an ink dot at a position on print media at or adjacent a position where the faulty nozzle would otherwise have printed it.

226. A printer comprising:
a printhead comprising at least a first elongate printhead module, the at least one printhead module including at least one row of print nozzles for expelling ink; and at least first and second printer controllers configured to receive print data and process the print data to output dot data to the printhead, wherein the first and second printer controllers are connected to a common input of the printhead.

227. A printer according to claim 226, including at least one synchronization means between the fust and second printer controllers for synchronizing the supply of dot by the printer controllers.

228. A printer according to claim 226, configured such that the first and second printer controllers sequentially provide the dot data to the common input.

229. A printer according to claim 226, further including a second printhead module, the printer being configured such that: the first printer controller outputs dot data to both the first printhead module and the second printhead module; and the second printer controller outputs dot data only to the second printhead module.

230. A printer according to claim 229, wherein the printhead modules are configured such that no dot data passes between them.

231. A printer according to claim 229, wherein each of the printer controllers is configurable to supply the dot data to printhead modules of a plurality of different lengths.

232. A printer according to claim 226, wherein the printhead is a pagewidth printhead.

233. A print engine comprising:
a carrier;
a printhead comprising at least a first elongate printhead module, the at least one printhead module including at least one row of print nozzles for expelling ink; and at least first and second printer controllers configured to receive print data and process the print data to output dot data to the printhead, wherein the first and second printer controllers are connected to a common input of the printhead.

234. A printer according to claim 233, including at least one synchronization means between the first and second printer controllers for synchronizing the supply of dot by the printer controllers.

235. A printer according to claim 233, configured such that the first and second printer controllers alternately provide the dot data to the common input.

236. A printer according to claim 233, further including a second printhead module, the printer being configured such that: the first printer controller outputs dot data to both the first printhead module and the second printhead module; and the second printer controller outputs dot data only to the second printhead module.

237. A printer according to claim 236, wherein the printhead modules are configured such that no dot data passes between them.

238. A printer according to claim 236, wherein each of the printer controllers is configurable to supply the dot data to printhead modules of a plurality of different lengths.

239. A printer according to claim 233, wherein the printhead is a pagewidth printhead.

240. A printer comprising:
a printhead comprising at least a first elongate printhead module, the at least one printhead module including at least first and second rows of print nozzles for expelling ink; and at least first and second printer controllers configured to receive print data and process the print data to output dot data to the printhead, wherein the first and second printer controllers are connected to the printhead to supply data for the first and second rows of nozzles, respectively.

241. A printer according to claim 240, including at least one synchronization means between the first and second printer controllers for synchronizing the supply of dot by the printer controllers.

242. A printer according to claim 240, wherein the printhead modules are configured such that no dot data passes between them.

243. A printer according to claim 240, wherein the printhead is a pagewidth printhead.

244. A printer according to claim 226, for implementing a method of at least partially compensating for errors in ink dot placement by at least one of a plurality of nozzles due to erroneous rotational displacement of a printhead module relative to a carrier, the nozzles being disposed on the printhead module, the method comprising the steps of:

determining the rotational displacement;
determining at least one correction factor that at least partially compensates for the ink dot displacement; and using the correction factor to alter the output of the ink dots to at least partially compensate for the rotational displacement.

245. A printer according to claim 226 for implementing a method of expelling ink from a printhead module including at least one row that comprises a plurality of adjacent sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, the method comprising providing, for each set of nozzles, a fire signal in accordance with the sequence: [nozzle position 1, nozzle position n, nozzle position 2, nozzle position (n-I), ... , nozzle position x], wherein nozzle position x is at or adjacent the centre of the set of nozzles.

246. A printer according to claim 226, for implementing a method of expelling ink from a printhead module including at least one row that comprises a plurality of sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, the method comprising the steps of:
(a). providing a fire signal to nozzles at a first and nth position in each set of nozzles;
(b). providing a fire signal to the next inward pair of nozzles in each set;
(c). in the event n is an even number, repeating step (b) until all of the nozzles in each set has been fired; and (d). in the event n is an odd number, repeating step (b) until all of the nozzles but a central nozzle in each set have been fired, and then firing the central nozzle.

247. A printer according to claim 226, manufactured in accordance with a method of manufacturing a plurality of printhead modules, at least some of which are capable of being combined in pairs to form bilithic pagewidth printheads, the method comprising the step of laying out each of the plurality of printhead modules on a wafer substrate, wherein at least one of the printhead modules is right-handed and at least another is left-handed.

248. A printer according to claim 226, including a printhead module including:
at least one row of print nozzles;
at least two shift registers for shifting in dot data supplied from a data source to each of the at least one rows, wherein each print nozzle obtains dot data to be fired from an element of one of the shift registers.

249. A printer according to claim 226, comprising:
a printhead comprising first and second elongate printhead modules, the printhead modules being parallel to each other and being disposed end to end on either side of a join region;
at least first and second printer controllers configured to receive print data and process the print data to output dot data to the printhead, wherein the first printer controller outputs dot data only to the first printhead module and the second printer controller outputs dot data only to the second printhead module, wherein the printhead modules are configured such that no dot data passes between them.

250. A printer according to claim 226, comprising:
a printhead comprising first and second elongate printhead modules, the printhead modules being parallel to each other and being disposed end to end on either side of a join region, wherein the first printhead module is longer than the second printhead module;
at least first and second printer controllers configured to receive print data and process the print data to output dot data to the printhead, wherein: the first printer controller outputs dot data to both the first printhead module and the second printhead module; and the second printer controller outputs dot data only to the second printhead module.

251. A printer according to claim 226, comprising:
a printhead comprising first and second elongate printhead modules, the printhead modules being parallel to each other and being disposed end to end on either side of a join region, wherein the first printhead module is longer than the second printhead module;
at least first and second printer controllers configured to receive print data and process the print data to output dot data for the printhead, wherein: the first printer controller outputs dot data to both the first printhead module and the second controller; and the second printer controller outputs dot data to the second printhead module, wherein the dot data output by the second printer controller includes dot data it generates and at least some of the dot data received from the first printer controller.

252. A printer according to claim 226, including at least one printhead module, configured for at least partially compensating for errors in ink dot placement by at least one of a plurality of nozzles on the printhead module due to erroneous rotational displacement of the printhead module relative to a carrier, the printer being configured to:
access a correction factor associated with the at least one printhead module; -determine an order in which at least some of the dot data is supplied to at least one of the at least one printhead modules, the order being determined at least partly on the basis of the correction factor, thereby to at least partially compensate for the rotational displacement; and supply the dot data to the printhead module.

253. A printer according to claim 226, including a printhead module having a plurality of nozzles for expelling ink, the printhead module including a plurality of thermal sensors, each of the thermal sensors being configured to respond to a temperature at or adjacent at least one of the nozzles, the printer being configured to modify operation of at least some of the nozzles in response to the temperature rising above a first threshold.

254. A printer according to claim 226, for controlling a printhead comprising at least one monolithic printhead module, the at least one printhead module having a plurality of rows of nozzles configured to extend, in use, across at least part of a printable pagewidth of the printhead, the nozzles in each row being grouped into at least first and second fire groups, the printhead module being configured to sequentially fire, for each row, the nozzles of each fire group, such that each nozzle in the sequence from each fire group is fired simultaneously with respective corresponding nozzles in the sequence in the other fire groups, wherein the nozzles are fired row by row such that the nozzles of each row are all fired before the nozzles of each subsequent row, wherein the printer controller is configured to provide one or more control signals that control the order of firing of the nozzles.

255. A printer according to claim 226, including a printer controller for sending to a printhead:
dot data to be printed with at least two different inks; and control data for controlling printing of the dot data;
the printer controller including at least one communication output, each or the communication output being configured to output at least some of the control data and at least some of the dot data for the at least two inks.

256. A printer according to claim 226, including a printer controller for supplying data to a printhead module including at least one row of printhead nozzles, at least one row including at least one displaced row portion, the displacement of the row portion including a component in a direction normal to that of a pagewidth to be printed.

257. A printer according to claim 226, including a printer controller for supplying print data to at least one printhead module capable of printing a maximum of n of channels of print data, the at least one printhead module being configurable into:
a first mode, in which the printhead module is configured to receive data for a first number of the channels; and a second mode, in which the printhead module is configured to receive print data for a second number of the channels, wherein the first number is greater than the second number;
wherein the printer controller is selectively configurable to supply dot data for the first and second modes.

258. A printer according to claim 226, including a printer controller for supplying data to a printhead comprising a plurality of printhead modules, the printhead being wider than a reticle step used in forming the modules, the printhead comprising at least two types of the modules, wherein each type is determined by its geometric shape in plan.

259. A printer according to claim 226, including a printer controller for supplying one or more control signals to a printhead module, the printhead module including at least one row that comprises a plurality of sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, such that:
(a). a fire signal is provided to nozzles at a first and nth position in each set of nozzles;
(b). a fire signal is provided to the next inward pair of nozzles in each set;

(c). in the event n is an even number, step (b) is repeated until all of the nozzles in each set has been fired;
and (d). in the event n is an odd number, step (b) is repeated until all of the nozzles but a central nozzle in each set have been fired, and then the central nozzle is fired.

260. A printer according to claim 226, including a printer controller for supplying one or more control signals to a printhead module, the printhead module including at least one row that comprises a plurality of adjacent sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, the method comprising providing, for each set of nozzles, a fire signal in accordance with the sequence: [nozzle position 1, nozzle position n, nozzle position 2, nozzle position (n-1), ... , nozzle position x], wherein nozzle position x is at or adjacent the centre of the set of nozzles.

261. A printer according to claim 226, including a printer controller for supplying dot data to a printhead module comprising at least first and second rows configured to print ink of a similar type or color, at least some nozzles in the first row being aligned with respective corresponding nozzles in the second row in a direction of intended media travel relative to the printhead, the printhead module being configurable such that the nozzles in the first and second pairs of rows are fired such that some dots output to print media are printed to by nozzles from the first pair of rows and at least some other dots output to print media are printed to by nozzles from the second pair of rows, the printer controller being configurable to supply dot data to the printhead module for printing.

262. A printer according to claim 226, including a printer controller for supplying dot data to at least one printhead module, the at least one printhead module comprising a plurality of rows, each of the rows comprising a plurality of nozzles for ejecting ink, wherein the printhead module includes at least first and second rows configured to print ink of a similar type or color, the printer controller being configured to supply the dot data to the at least one printhead module such that, in the event a nozzle in the first row is faulty, a corresponding nozzle in the second row prints an ink dot at a position on print media at or adjacent a position where the faulty nozzle would otherwise have printed it.

263. A printer according to claim 226, including a printer controller for receiving first data and manipulating the first data to produce dot data to be printed, the print controller including at least two serial outputs for supplying the dot data to at least one printhead.

264. A printer according to claim 226, including a printer controller for supplying data to a printhead module including:
at least one row of print nozzles;

at least first and second shift registers for shifting in dot data supplied from a data source, wherein each shift register feeds dot data to a group of nozzles, and wherein each of the groups of the nozzles is interleaved with at least one of the other groups of the nozzles.

265. A printer according to claim 226, including a printer controller for supplying data to a printhead capable of printing a maximum of n of channels of print data, the printhead being configurable into:
a first mode, in which the printhead is configured to receive print data for a first number of the channels; and a second mode, in which the printhead is configured to receive print data for a second number of the channels, wherein the first number is greater than the second number.

266. A printer according to claim 226, including a printer controller for supplying data to a printhead comprising a plurality of printhead modules, the printhead being wider than a reticle step used in forming the modules, the printhead comprising at least two types of the modules, wherein each type is determined by its geometric shape in plan.

267. A printer according to claim 226, including a printer controller for supplying data to a printhead module including at least one row that comprises a plurality of sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, such that, for each set of nozzles, a fire signal is provided in accordance with the sequence: [nozzle position 1, nozzle position n, nozzle position 2, nozzle position (n-1), ... , nozzle position x], wherein nozzle position x is at or adjacent the centre of the set of nozzles.

268. A printer according to claim 226, including a printer controller for supplying data to a printhead module including at least one row that comprises a plurality of adjacent sets of n adjacent nozzles, each of the nozzles being configured to expel the ink in response to a fire signal, the printhead being configured to output ink from nozzles at a first and nth position in each set of nozzles, and then each next inward pair of nozzles in each set, until:
in the event n is an even number, all of the nozzles in each set has been fired; and in the event n is an odd number, all of the nozzles but a central nozzle in each set have been fired, and then to fire the central nozzle.

269. A printer according to claim 226, including a printer controller for supplying data to a printhead module for receiving dot data to be printed using at least two different inks and control data for controlling printing of the dot data, the printhead module including a communication input for receiving the dot data for the at least two colors and the control data.

270. A printer according to claim 226, including a printer controller for supplying data to a printhead module including at least one row of printhead nozzles, at least one row including at least one displaced row portion, the displacement of the row portion including a component in a direction normal to that of a pagewidth to be printed.

271. A printer according to claim 226, including a printer controller for supplying data to a printhead module having a plurality of rows of nozzles configured to extend, in use, across at least part of a printable pagewidth, the nozzles in each row being grouped into at least first and second fire groups, the printhead module being configured to sequentially fire, for each row, the nozzles of each fire group, such that each nozzle in the sequence from each fire group is fired simultaneously with respective corresponding nozzles in the sequence in the other fire groups, wherein the nozzles are fired row by row such that the nozzles of each row are all fired before the nozzles of each subsequent row.

272. A printer according to claim 226, including a printer controller for supplying data to a printhead module comprising at least first and second rows configured to print ink of a similar type or color, at least some nozzles in the first row being aligned with respective corresponding nozzles in the second row in a direction of intended media travel relative to the printhead, the printhead module being configurable such that the nozzles in the first and second pairs of rows are fired such that some dots output to print media are printed to by nozzles from the first pair of rows and at least some other dots output to print media are printed to by nozzles from the second pair of rows.

273. A printer according to claim 226, including a printer controller for providing data to a printhead module that includes:
at least one row of print nozzles;
at least first and second shift registers for shifting in dot data supplied from a data source, wherein each shift register feeds dot data to a group of nozzles, and wherein each of the groups of the nozzles is interleaved with at least one of the other groups of the nozzles.

274. A printer according to claim 226, including a printer controller for supplying data to a printhead module having a plurality of nozzles for expelling ink, the printhead module including a plurality of thermal sensors, each of the thermal sensors being configured to respond to a temperature at or adjacent at least one of the nozzles, the printhead module being configured to modify operation of the nozzles in response to the temperature rising above a first threshold.

275. A printer according to claim 226, including a printer controller for supplying data to a printhead module comprising a plurality of rows, each of the rows comprising a plurality of nozzles for ejecting ink, wherein the printhead module includes at least first and second rows configured to print ink of a similar type or color, and being configured such that, in the event a nozzle in the first row is faulty, a corresponding nozzle in the second row prints an ink dot at a position on print media at or adjacent a position where the faulty nozzle would otherwise have printed it.

276. A printer comprising:
a printhead comprising first and second elongate printhead modules, the printhead modules being parallel to each other and being disposed end to end on either side of a join region;
at least first and second printer controllers configured to receive print data and process the print data to output dot data to the printhead, wherein the first printer controller outputs dot data only to the first printhead module and the second printer controller outputs dot data only to the second printhead module, wherein the printhead modules are configured such that no dot data passes between them.

277. A printer according to claim 276, including at least one synchronization means between the first and second printer controllers for synchronizing the supply of dot by the printer controllers.

278. A printer according to claim 276, wherein each of the printer controllers is configurable to supply the dot data to a printhead module of arbitrary length.

279. A printer according to claim 276, wherein the first and second printhead modules are equal in length.

280. A printer according to claim 276, wherein the first and second printhead modules are unequal in length.

281. A printer according to claim 276, wherein the printhead is a pagewidth printhead.

282. A print engine comprising:
a carrier;
a printhead comprising first and second elongate printhead modules, the printhead modules being mounted parallel to each other end to end on the carrier on either side of a join region;
at least first and second printer controllers mounted on the carrier and being configured to receive print data and process the print data to output dot data to the printhead, wherein the first printer controller outputs dot data only to the first printhead module and the second printer controller outputs dot data only to the second printhead module, wherein the printhead modules are configured such that no dot data passes between them.

283. A print engine according to claim 282, including at least one synchronization means between the first and second printer controllers for synchronizing the supply of dot by the printer controllers.

284. A print engine according to claim 282, wherein each of the printer controllers is configurable to supply the dot data to a printhead module of arbitrary length.

285. A print engine according to claim 282, wherein the first and second printhead modules are equal in length.

286. A print engine according to claim 282, wherein the first and second printhead modules are unequal in length.

287. A print engine according to claim 282, wherein the printhead is a pagewidth printhead.

288. A printer according to claim 276, for implementing a method of at least partially compensating for errors in ink dot placement by at least one of a plurality of nozzles due to erroneous rotational displacement of a printhead module relative to a carrier, the nozzles being disposed on the printhead module, the method comprising the steps of:
determining the rotational displacement;
determining at least one correction factor that at least partially compensates for the ink dot displacement; and using the correction factor to alter the output of the ink dots to at least partially compensate for the rotational displacement.

289. A printer according to claim 276 for implementing a method of expelling ink from a printhead module including at least one row that comprises a plurality of adjacent sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, the method comprising providing, for each set of nozzles, a fire signal in accordance with the sequence: [nozzle position 1, nozzle position n, nozzle position 2, nozzle position (n-1), ... , nozzle position x], wherein nozzle position x is at or adjacent the centre of the set of nozzles.

290. A printer according to claim 276, for implementing a method of expelling ink from a printhead module including at least one row that comprises a plurality of sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, the method comprising the steps of:
providing a fire signal to nozzles at a first and nth position in each set of nozzles;
providing a fire signal to the next inward pair of nozzles in each set;
in the event n is an even number, repeating step (b) until all of the nozzles in each set has been fired; and in the event n is an odd number, repeating step (b) until all of the nozzles but a central nozzle in each set have been fired, and then firing the central nozzle.

291. A printer according to claim 276, manufactured in accordance with a method of manufacturing a plurality of printhead modules, at least some of which are capable of being combined in pairs to form bilithic pagewidth printheads, the method comprising the step of laying out each of the plurality of printhead modules on a wafer substrate, wherein at least one of the printhead modules is right-handed and at least another is left-handed.

292. A printer according to claim 276, including a printhead module including:

at least one row of print nozzles;
at least two shift registers for shifting in dot data supplied from a data source to each of the at least one rows, wherein each print nozzle obtains dot data to be fired from an element of one of the shift registers.

293. A printer according to claim 276, comprising:
a printhead comprising at least a first elongate printhead module, the at least one printhead module including at least one row of print nozzles for expelling ink; and at least first and second printer controllers configured to receive print data and process the print data to output dot data to the printhead, wherein the first and second printer controllers are connected to a common input of the printhead.

294. A printer according to claim 276, comprising:
a printhead comprising first and second elongate printhead modules, the printhead modules being parallel to each other and being disposed end to end on either side of a join region, wherein the first printhead module is longer than the second printhead module;
at least first and second printer controllers configured to receive print data and process the print data to output dot data to the printhead, wherein: the first printer controller outputs dot data to both the first printhead module and the second printhead module; and the second printer controller outputs dot data only to the second printhead module.

295. A printer according to claim 276, comprising:
a printhead comprising first and second elongate printhead modules, the printhead modules being parallel to each other and being disposed end to end on either side of a join region, wherein the first printhead module is longer than the second printhead module;
at least first and second printer controllers configured to receive print data and process the print data to output dot data for the printhead, wherein: the first printer controller outputs dot data to both the first printhead module and the second controller; and the second printer controller outputs dot data to the second printhead module, wherein the dot data output by the second printer controller includes dot data it generates and at least some of the dot data received from the first printer controller.

296. A printer according to claim 276, including at least one printhead module, configured for at least partially compensating for errors in ink dot placement by at least one of a plurality of nozzles on the printhead module due to erroneous rotational displacement of the printhead module relative to a carrier, the printer being configured to:
access a correction factor associated with the at least one printhead module;

determine an order in which at least some of the dot data is supplied to at least one of the at least one printhead modules, the order being determined at least partly on the basis of the correction factor, thereby to at least partially compensate for the rotational displacement; and supply the dot data to the printhead module.

297. A printer according to claim 276, including a printhead module having a plurality of nozzles for expelling ink, the printhead module including a plurality of thermal sensors, each of the thermal sensors being configured to respond to a temperature at or adjacent at least one of the nozzles, the printer being configured to modify operation of at least some of the nozzles in response to the temperature rising above a first threshold.

298. . A printer according to claim 276, for controlling a printhead comprising at least one monolithic printhead module, the at least one printhead module having a plurality of rows of nozzles configured to extend, in use, across at least part of a printable pagewidth of the printhead, the nozzles in each row being grouped into at least first and second fire groups, the printhead module being configured to sequentially fire, for each row, the nozzles of each fire group, such that each nozzle in the sequence from each fire group is fired simultaneously with respective corresponding nozzles in the sequence in the other fire groups, wherein the nozzles are fired row by row such that the nozzles of each row are all fired before the nozzles of each subsequent row, wherein the printer controller is configured to provide one or more control signals that control the order of firing of the nozzles.

299. A printer according to claim 276, including a printer controller for sending to a printhead:
dot data to be printed with at least two different inks; and control data for controlling printing of the dot data;
the printer controller including at least one communication output, each or the communication output being configured to output at least some of the control data and at least some of the dot data for the at least two inks.

300. A printer according to claim 276, including a printer controller for supplying data to a printhead module including at least one row of printhead nozzles, at least one row including at least one displaced row portion, the displacement of the row portion including a component in a direction normal to that of a pagewidth to be printed.

301. A printer according to claim 276, including a printer controller for supplying print data to at least one printhead module capable of printing a maximum of n of channels of print data, the at least one printhead module being configurable into:
a first mode, in which the printhead module is configured to receive data for a first number of the channels; and a second mode, in which the printhead module is configured to receive print data for a second number of the channels, wherein the first number is greater than the second number;
wherein the printer controller is selectively configurable to supply dot data for the first and second modes.

302. A printer according to claim 276, including a printer controller for supplying data to a printhead comprising a plurality of printhead modules, the printhead being wider than a reticle step used in forming the modules, the printhead comprising at least two types of the modules, wherein each type is determined by its geometric shape in plan.

303. A printer according to claim 276, including a printer controller for supplying one or more control signals to a printhead module, the printhead module including at least one row that comprises a plurality of sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, such that:
(a). a fire signal is provided to nozzles at a first and nth position in each set of nozzles;
(b). a fire signal is provided to the next inward pair of nozzles in each set;
(c). in the event n is an even number, step (b) is repeated until all of the nozzles in each set has been fired;
and (d). in the event n is an odd number, step (b) is repeated until all of the nozzles but a central nozzle in each set have been fired, and then the central nozzle is fired.

304. A printer according to claim 276, including a printer controller for supplying one or more control signals to a printhead module, the printhead module including at least one row that comprises a plurality of adjacent sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, the method comprising providing, for each set of nozzles, a fire signal in accordance with the sequence: [nozzle position 1, nozzle position n, nozzle position 2, nozzle position (n-1), ... , nozzle position x], wherein nozzle position x is at or adjacent the centre of the set of nozzles.

305. A printer according to claim 276, including a printer controller for supplying dot data to a printhead module comprising at least first and second rows configured to print ink of a similar type or color, at least some nozzles in the first row being aligned with respective corresponding nozzles in the second row in a direction of intended media travel relative to the printhead, the printhead module being configurable such that the nozzles in the first and second pairs of rows are fired such that some dots output to print media are printed to by nozzles from the first pair of rows and at least some other dots output to print media are printed to by nozzles from the second pair of rows, the printer controller being configurable to supply dot data to the printhead module for printing.

306. A printer according to claim 276, including a printer controller for supplying dot data to at least one printhead module, the at least one printhead module comprising a plurality of rows, each of the rows comprising a plurality of nozzles for ejecting ink, wherein the printhead module includes at least first and second rows configured to print ink of a similar type or color, the printer controller being configured to supply the dot data to the at least one printhead module such that, in the event a nozzle in the first row is faulty, a corresponding nozzle in the second row prints an ink dot at a position on print media at or adjacent a position where the faulty nozzle would otherwise have printed it.

307. A printer according to claim 276, including a printer controller for receiving first data and manipulating the first data to produce dot data to be printed, the print controller including at least two serial outputs for supplying the dot data to at least one printhead.

308. A printer according to claim 276, including a printer controller for supplying data to a printhead module including:
at least one row of print nozzles;
at least first and second shift registers for shifting in dot data supplied from a data source, wherein each shift register feeds dot data to a group of nozzles, and wherein each of the groups of the nozzles is interleaved with at least one of the other groups of the nozzles.

309. A printer according to claim 276, including a printer controller for supplying data to a printhead capable of printing a maximum of n of channels of print data, the printhead being configurable into:
a first mode, in which the printhead is configured to receive print data for a first number of the channels; and a second mode, in which the printhead is configured to receive print data for a second number of the channels, wherein the first number is greater than the second number.

310. A printer according to claim 276, including a printer controller for supplying data to a printhead comprising a plurality of printhead modules, the printhead being wider than a reticle step used in forming the modules, the printhead comprising at least two types of the modules, wherein each type is determined by its geometric shape in plan.

311. A printer according to claim 276, including a printer controller for supplying data to a printhead module including at least one row that comprises a plurality of sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, such that, for each set of nozzles, a fire signal is provided in accordance with the sequence: [nozzle position 1, nozzle position n, nozzle position 2, nozzle position (n-1), ... , nozzle position x], wherein nozzle position x is at or adjacent the centre of the set of nozzles.

312. A printer according to claim 276, including a printer controller for supplying data to a printhead module including at least one row that comprises a plurality of adjacent sets of n adjacent nozzles, each of the nozzles being configured to expel the ink in response to a fire signal, the printhead being configured to output ink from nozzles at a first and nth position in each set of nozzles, and then each next inward pair of nozzles in each set, until:
in the event n is an even number, all of the nozzles in each set has been fired; and in the event n is an odd number, all of the nozzles but a central nozzle in each set have been fired, and then to fire the central nozzle.

313. A printer according to claim 276, including a printer controller for supplying data to a printhead module for receiving dot data to be printed using at least two different inks and control data for controlling printing of the dot data, the printhead module including a communication input for receiving the dot data for the at least two colors and the control data.

314. A printer according to claim 276, including a printer controller for supplying data to a printhead module including at least one row of printhead nozzles, at least one row including at least one displaced row portion, the displacement of the row portion including a component in a direction normal to that of a pagewidth to be printed.

315. A printer according to claim 276, including a printer controller for supplying data to a printhead module having a plurality of rows of nozzles configured to extend, in use, across at least part of a printable pagewidth, the nozzles in each row being grouped into at least first and second fire groups, the printhead module being configured to sequentially fire, for each row, the nozzles of each fire group, such that each nozzle in the sequence from each fire group is fired simultaneously with respective corresponding nozzles in the sequence in the other fire groups, wherein the nozzles are fired row by row such that the nozzles of each row are all fired before the nozzles of each subsequent row.

316. A printer according to claim 276, including a printer controller for supplying data to a printhead module comprising at least first and second rows configured to print ink of a similar type or color, at least some nozzles in the first row being aligned with respective corresponding nozzles in the second row in a direction of intended media travel relative to the printhead, the printhead module being configurable such that the nozzles in the first and second pairs of rows are fired such that some dots output to print media are printed to by nozzles from the first pair of rows and at least some other dots output to print media are printed to by nozzles from the second pair of rows.

317. A printer according to claim 276, including a printer controller for providing data to a printhead module that includes:
at least one row of print nozzles;
at least first and second shift registers for shifting in dot data supplied from a data source, wherein each shift register feeds dot data to a group of nozzles, and wherein each of the groups of the nozzles is interleaved with at least one of the other groups of the nozzles.

318. A printer according to claim 276, including a printer controller for supplying data to a printhead module having a plurality of nozzles for expelling ink, the printhead module including a plurality of thermal sensors, each of the thermal sensors being configured to respond to a temperature at or adjacent at least one of the nozzles, the printhead module being configured to modify operation of the nozzles in response to the temperature rising above a first threshold.

319. A printer according to claim 276, including a printer controller for supplying data to a printhead module comprising a plurality of rows, each of the rows comprising a plurality of nozzles for ejecting ink, wherein the printhead module includes at least first and second rows configured to print ink of a similar type or color, and being configured such that, in the event a nozzle in the first row is faulty, a corresponding nozzle in the second row prints an ink dot at a position on print media at or adjacent a position where the faulty nozzle would otherwise have printed it.

320. A printer comprising:
a printhead comprising first and second elongate printhead modules, the printhead modules being parallel to each other and being disposed end to end on either side of a join region, wherein the first printhead module is longer than the second printhead module;
at least first and second printer controllers configured to receive print data and process the print data to output dot data to the printhead, wherein: the first printer controller outputs dot data to both the first printhead module and the second printhead module; and the second printer controller outputs dot data only to the second printhead module.

321. A printer according to claim 320, wherein the printhead modules are configured such that no dot data passes between them.

322. A printer according to claim 320, including at least one synchronization means between the first and second printer controllers for synchronizing the supply of dot data by the printer controllers.

323. A printer according to claim 320, wherein each of the printer controllers is configurable to supply the dot data to printhead modules of a plurality of different lengths.

324. A printer according to claim 320, wherein the printhead is a pagewidth printhead.

325. A print engine comprising:
a carrier;
a printhead comprising first and second elongate printhead modules, the printhead modules being mounted parallel to each other end to end on the carrier on either side of a join region, wherein the first printhead module is longer than the second printhead module;

at least first and second printer controllers mounted on the carrier and being configured to receive print data and process the print data to output dot data to the printhead, wherein: the first printer controller outputs dot data to both the first printhead module and the second printhead module;. and the second printer controller outputs dot data only to the second printhead module.

326. A print engine according to claim 325, wherein the printhead modules are configured such that no dot data passes between them.

327. A print engine according to claim 326, including at least one synchronization means between the first and second printer controllers for synchronizing the supply of dot by the printer controllers.

328. A print engine according to claim 326, wherein each of the printer controllers is configurable to supply the dot data to printhead modules of a plurality of different lengths.

329. A print engine according to claim 326, wherein the printhead is a pagewidth printhead.

330. A printer according to claim 320, for implementing a method of at least partially compensating for errors in ink dot placement by at least one of a plurality of nozzles due to erroneous rotational displacement of a printhead module relative to a carrier, the nozzles being disposed on the printhead module, the method comprising the steps of:
determining the rotational displacement;
determining at least one correction factor that at least partially compensates for the ink dot displacement; and using the correction factor to alter the output of the ink dots to at least partially compensate for the rotational displacement.

331. A printer according to claim 320 for implementing a method of expelling ink from a printhead module including at least one row that comprises a plurality of adjacent sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, the method comprising providing, for each set of nozzles, a fire signal in accordance with the sequence: [nozzle position 1, nozzle position n, nozzle position 2, nozzle position (n-1), ... , nozzle position x], wherein nozzle position x is at or adjacent the centre of the set of nozzles.

332. A printer according to claim 320, for implementing a method of expelling ink from a printhead module including at least one row that comprises a plurality of sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, the method comprising the steps of:
(a). providing a fire signal to nozzles at a first and nth position in each set of nozzles;
(b). providing a fire signal to the next inward pair of nozzles in each set;

(c). in the event n is an even number, repeating step (b) until all of the nozzles in each set has been fired; and (d). in the event n is an odd number, repeating step (b) until all of the nozzles but a central nozzle in each set have been fired, and then firing the central nozzle.

333. A printer according to claim 320, manufactured in accordance with a method of manufacturing a plurality of printhead modules, at least some of which are capable of being combined in pairs to form bilithic pagewidth printheads, the method comprising the step of laying out each of the plurality of printhead modules on a wafer substrate, wherein at least one of the printhead modules is right-handed and at least another is left-handed.

334. A printer according to claim 320, including a printhead module including:
at least one row of print nozzles;
at least two shift registers for shifting in dot data supplied from a data source to each of the at least one rows, wherein each print nozzle obtains dot data to be fired from an element of one of the shift registers.

335. A printer according to claim 320, comprising:
a printhead comprising at least a first elongate printhead module, the at least one printhead module including at least one row of print nozzles for expelling ink; and at least first and second printer controllers configured to receive print data and process the print data to output dot data to the printhead, wherein the first and second printer controllers are connected to a common input of the printhead.

336. A printer according to claim 320, comprising:
a printhead comprising first and second elongate printhead modules, the printhead modules being parallel to each other and being disposed end to end on either side of a join region;
at least first and second printer controllers configured to receive print data and process the print data to output dot data to the printhead, wherein the first printer controller outputs dot data only to the first printhead module and the second printer controller outputs dot data only to the second printhead module, wherein the printhead modules are configured such that no dot data passes between them.

337. A printer according to claim 320, comprising:
a printhead comprising first and second elongate printhead modules, the printhead modules being parallel to each other and being disposed end to end on either side of a join region, wherein the first printhead module is longer than the second printhead module;
at least first and second printer controllers configured to receive print data and process the print data to output dot data for the printhead, wherein: the first printer controller outputs dot data to both the first printhead module and the second controller; and the second printer controller outputs dot data to the second printhead module, wherein the dot data output by the second printer controller includes dot data it generates and at least some of the dot data received from the first printer controller.

338. A printer according to claim 320, including at least one printhead module, configured for at least partially compensating for errors in ink dot placement by at least one of a plurality of nozzles on the printhead module due to erroneous rotational displacement of the printhead module relative to a carrier, the printer being configured to:
access a correction factor associated with the at least one printhead module;
determine an order in which at least some of the dot data is supplied to at least one of the at least one printhead modules, the order being determined at least partly on the basis of the correction factor, thereby to at least partially compensate for the rotational displacement; and supply the dot data to the printhead module.

339. A printer according to claim 320, including a printhead module having a plurality of nozzles for expelling ink, the printhead module including a plurality of thermal sensors, each of the thermal sensors being configured to respond to a temperature at or adjacent at least one of the nozzles, the printer being configured to modify operation of at least some of the nozzles in response to the temperature rising above a first threshold.

340. A printer according to claim 320, for controlling a printhead comprising at least one monolithic printhead module, the at least one printhead module having a plurality of rows of nozzles configured to extend, in use, across at least part of a printable pagewidth of the printhead, the nozzles in each row being grouped into at least first and second fire groups, the printhead module being configured to sequentially fire, for each row, the nozzles of each fire group, such that each nozzle in the sequence from each fire group is fired simultaneously with respective corresponding nozzles in the sequence in the other fire groups, wherein the nozzles are fired row by row such that the nozzles of each row are all fired before the nozzles of each subsequent row, wherein the printer controller is configured to provide one or more control signals that control the order of firing of the nozzles.

341. A printer according to claim 320, including a printer controller for sending to a printhead:
dot data to be printed with at least two different inks; and control data for controlling printing of the dot data;
the printer controller including at least one communication output, each or the communication output being configured to output at least some of the control data and at least some of the dot data for the at least two inks.

342. A printer according to claim 320, including a printer controller for supplying data to a printhead module including at least one row of printhead nozzles, at least one row including at least one displaced row portion, the displacement of the row portion including a component in a direction normal to that of a pagewidth to be printed.

343. A printer according to claim 320, including a printer controller for supplying print data to at least one printhead module capable of printing a maximum of n of channels of print data, the at least one printhead module being configurable into:
a first mode, in which the printhead module is configured to receive data for a first number of the channels; and a second mode, in which the printhead module is configured to receive print data for a second number of the channels, wherein the first number is greater than the second number;
wherein.the printer controller is selectively configurable to supply dot data for the first and second modes.

344. A printer according to claim 320, including a printer controller for supplying data to a printhead comprising a plurality of printhead modules, the printhead being wider than a reticle step used in forming the modules, the printhead comprising at least two types of the modules, wherein each type is determined by its geometric shape in plan.

345. A printer according to claim 320, including a printer controller for supplying one or more control signals to a printhead module, the printhead module including at least one row that comprises a plurality of sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, such that:
(a). a fire signal is provided to nozzles at a first and nth position in each set of nozzles;
(b). a fire signal is provided to the next inward pair of nozzles in each set;
(c). in the event n is an even number, step (b) is repeated until all of the nozzles in each set has been fired;
and (d). in the event n is an odd number, step (b) is repeated until all of the nozzles but a central nozzle in each set have been fired, and then the central nozzle is fired.

346. A printer according to claim 320, including a printer controller for supplying one or more control signals to a printhead module, the printhead module including at least one row that comprises a plurality of adjacent sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, the method comprising providing, for each set of nozzles, a fire signal in accordance with the sequence: [nozzle position 1, nozzle position n, nozzle position 2, nozzle position (n-1), ... , nozzle position x], wherein nozzle position x is at or adjacent the centre of the set of nozzles.

347. A printer according to claim 320, including a printer controller for supplying dot data to a printhead module comprising at least first and second rows configured to print ink of a similar type or color, at least some nozzles in the first row being aligned with respective corresponding nozzles in the second row in a direction of intended media travel relative to the printhead, the printhead module being configurable such that the nozzles in the first and second pairs of rows are fired such that some dots output to print media are printed to by nozzles from the first pair of rows and at least some other dots output to print media are printed to by nozzles from the second pair of rows, the printer controller being configurable to supply dot data to the printhead module for printing.

348. A printer according to claim 320, including a printer controller for supplying dot data to at least one printhead module, the at least one printhead module comprising a plurality of rows, each of the rows comprising a plurality of nozzles for ejecting ink, wherein the printhead module includes at least first and second rows configured to print ink of a similar type or color, the printer controller being configured to supply the dot data to the at least one printhead module such that, in the event a nozzle in the first row is faulty, a corresponding nozzle in the second row prints an ink dot at a position on print media at or adjacent a position where the faulty nozzle would otherwise have printed it.

349. A printer according to claim 320, including a printer controller for receiving first data and manipulating the first data to produce dot data to be printed, the print controller including at least two serial outputs for supplying the dot data to at least one printhead.

350. A printer according to claim 320, including a printer controller for supplying data to a printhead module including:
at least one row of print nozzles;
at least first and second shift registers for shifting in dot data supplied from a data source, wherein each shift register feeds dot data to a group of nozzles, and wherein each of the groups of the nozzles is interleaved with at least one of the other groups of the nozzles.

351. A printer according to claim 320, including a printer controller for supplying data to a printhead capable of printing a maximum of n of channels of print data, the printhead being configurable into:
a first mode, in which the printhead is configured to receive print data for a first number of the channels; and a second mode, in which the printhead is configured to receive print data for a second number of the channels, wherein the first number is greater than the second number.

352. A printer according to claim 320, including a printer controller for supplying data to a printhead comprising a plurality of printhead modules, the printhead being wider than a reticle step used in forming the modules, the printhead comprising at least two types of the modules, wherein each type is determined by its geometric shape in plan.

353. A printer according to claim 320, including a printer controller for supplying data to a printhead module including at least one row that comprises a plurality of sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, such that, for each set of nozzles, a fire signal is provided in accordance with the sequence: [nozzle position 1, nozzle position n, nozzle position 2, nozzle position (n-1), ... , nozzle position x], wherein nozzle position x is at or adjacent the centre of the set of nozzles.

354. A printer according to claim 320, including a printer controller for supplying data to a printhead module including at least one row that comprises a plurality of adjacent sets of n adjacent nozzles, each of the nozzles being configured to expel the ink in response to a fire signal, the printhead being configured to output ink from nozzles at a first and nth position in each set of nozzles, and then each next inward pair of nozzles in each set, until:
in the event n is an even number, all of the nozzles in each set has been fired; and in the event n is an odd number, all of the nozzles but a central nozzle in each set have been fired, and then to fire the central nozzle.

355. A printer according to claim 320, including a printer controller for supplying data to a printhead module for receiving dot data to be printed using at least two different inks and control data for controlling printing of the dot data, the printhead module including a communication input for receiving the dot data for the at least two colors and the control data.

356. A printer according to claim 320, including a printer controller for supplying data to a printhead module including at least one row of printhead nozzles, at least one row including at least one displaced row portion, the displacement of the row portion including a component in a direction normal to that of a pagewidth to be printed.

357. A printer according to claim 320, including a printer controller for supplying data to a printhead module having a plurality of rows of nozzles configured to extend, in use, across at least part of a printable pagewidth, the nozzles in each row being grouped into at least first and second fire groups, the printhead module being configured to sequentially fire, for each row, the nozzles of each fire group, such that each nozzle in the sequence from each fire group is fired simultaneously with respective corresponding nozzles in the sequence in the other fire groups, wherein the nozzles are fired row by row such that the nozzles of each row are all fired before the nozzles of each subsequent row:

358. A printer according to claim 320, including a printer controller for supplying data to a printhead module comprising at least first and second rows configured to print ink of a similar type or color, at least some nozzles in the first row being aligned with respective corresponding nozzles in the second row in a direction of intended media travel relative to the printhead, the printhead module being configurable such that the nozzles in the first and second pairs of rows are fired such that some dots output to print media are printed to by nozzles from the first pair of rows and at least some other dots output to print media are printed to by nozzles from the second pair of rows.

359. A printer according to claim 320, including a printer controller for providing data to a printhead module that includes:
at least one row of print nozzles;
at least first and second shift registers for shifting in dot data supplied from a data source, wherein each shift register feeds dot data to a group of nozzles, and wherein each of the groups of the nozzles is interleaved with at least one of the other groups of the nozzles.

360. A printer according to claim 320, including a printer controller for supplying data to a printhead module having a plurality of nozzles for expelling ink, the printhead module including a plurality of thermal sensors, each of the thermal sensors being configured to respond to a temperature at or adjacent at least one of the nozzles, the printhead module being configured to modify operation of the nozzles in response to the temperature rising above a first threshold.

361. A printer according to claim 320, including a printer controller for supplying data to a printhead module comprising a plurality of rows, each of the rows comprising a plurality of nozzles for ejecting ink, wherein the printhead module includes at least first and second rows configured to print ink of a similar type or color, and being configured such that, in the event a nozzle in the first row is faulty, a corresponding nozzle in the second row prints an ink dot at a position on print media at or adjacent a position where the faulty nozzle would otherwise have printed it.

362. A printer comprising:
a printhead comprising first and second elongate printhead modules, the printhead modules being parallel to each other and being disposed end to end on either side of a join region, wherein the first printhead module is longer than the second printhead module;
at least first and second printer controllers configured to receive print data and process the print data to output dot.
data for the printhead, wherein: the first printer controller outputs dot data to both the first printhead module and the second controller; and the second printer controller outputs dot data to the second printhead module, wherein the dot data output by the second printer controller includes dot data it generates and at least some of the dot data received from the first printer controller.

363. A printer according to claim 362, wherein the printhead modules are configured such that no dot data passes between them.

364. A printer according to claim 362, including at least one synchronization means between the first and second printer controllers for synchronizing the supply of dot data by the printer controllers.

365. A printer according to claim 362, wherein each of the printer controllers is configurable to supply the dot data to printhead modules of a plurality of different lengths.

366. A printer according to claim 362, wherein the printhead is a pagewidth printhead.

367. A print engine comprising:
a carrier;
a printhead comprising first and second elongate printhead modules, the printhead modules being mounted parallel to each other end to end on the carrier on either side of a join region, wherein the first printhead module is longer than the'second printhead module;
at least first and second printer controllers configured to receive print data and process the print data to output dot data for the printhead, wherein: the first printer controller outputs dot data to both the first printhead module and the second controller; and the second printer controller outputs dot data to the second-printhead module, wherein the dot data output by the second printer controller includes dot data it generates and at least some of the dot data received from the first printer controller.

368. A print engine according to claim 367, wherein the printhead modules are configured such that no dot data passes between them.

369. A print engine according to claim 368, including at least one synchronization means between the first and second printer controllers for synchronizing the supply of dot by the printer controllers.

370. A print engine according to claim 368, wherein each of the printer controllers is configurable to supply the dot data to printhead modules of a plurality of different lengths.

371. A print engine according to claim 368, wherein the printhead is a pagewidth printhead.

372. A printer controller according to claim 362, for implementing a method of at least partially compensating for errors in ink dot placement by at least one of a plurality of nozzles due to erroneous rotational displacement of a printhead module relative to a carrier, the nozzles being disposed on the printhead module, the method comprising the steps of:
determining the rotational displacement;
determining at least one correction factor that at least partially compensates for the ink dot displacement; and using the correction factor to alter the output of the ink dots to at least partially compensate for the rotational displacement.

373. A printer controller according to claim 362 for implementing a method of expelling ink from a printhead module including at least one row that comprises a plurality of adjacent sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, the method comprising providing, for each set of nozzles, a fire signal in accordance with the sequence: [nozzle position 1, nozzle position n, nozzle position 2, nozzle position (n-1), ... , nozzle position x], wherein nozzle position x is at or adjacent the centre of the set of nozzles.

374. A printer controller according to claim 362, for implementing a method of expelling ink from a printhead module including at least one row that comprises a plurality of sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, the method comprising the steps of:
(a). providing a fire signal to nozzles at a first and nth position in each set of nozzles;
(b). providing a fire signal to the next inward pair of nozzles in each set;
(c). in the event n is an even number, repeating step (b) until all of the nozzles in each set has been fired; and (d). in the event n is an odd number, repeating step (b) until all of the nozzles but a central nozzle in each set have been fired, and then firing the central nozzle.

375. A printer controller according to claim 362, manufactured in accordance with a method of manufacturing a plurality of printhead modules, at least some of which are capable of being combined in pairs to form bilithic pagewidth printheads, the method comprising the step of laying out each of the plurality of printhead modules on a wafer substrate, wherein at least one of the printhead modules is right-handed and at least another is left-handed.

376. A printer controller according to claim 362, for supplying data to a printhead module including:
at least one row of print nozzles;
at least two shift registers for shifting in dot data supplied from a data source to each of the at least one rows, wherein each print nozzle obtains dot data to be fired from an element of one of the shift registers.

377. A printer controller according to claim 362, installed in a printer comprising:
a printhead comprising at least a first elongate printhead module, the at least one printhead module including at least one row of print nozzles for expelling ink; and at least first and second printer controllers configured to receive print data and process the print data to output dot data to the printhead, wherein the first and second printer controllers are connected to a common input of the printhead.

378. A printer controller according to claim 362, installed in a printer comprising:
a printhead comprising first and second elongate printhead modules, the printhead modules being parallel to each other and being disposed end to end on either side of a join region;

at least first and second printer controllers configured to receive print data and process the print data to output dot data to the printhead, wherein the first printer controller outputs dot data only to the first printhead module and the second printer controller outputs dot data only to the second printhead module, wherein the printhead modules are configured such that no dot data passes between them.

379. A printer controller according to claim 362, installed in a printer comprising:
a printhead comprising first and second elongate printhead modules, the printhead modules being parallel to each other and being disposed end to end on either side of a join region, wherein the first printhead module is longer than the second printhead module;
at least first and second printer controllers configured to receive print data and process the print data to output dot data to the printhead, wherein: the first printer controller outputs dot data to both the first printhead module and the second printhead module; and the second printer controller outputs dot data only to the second printhead module.

380. A printer controller according to claim 362, for supplying dot data to at least one printhead module and at least partially compensating for errors in ink dot placement by at least one of a plurality of nozzles on the printhead module due to erroneous rotational displacement of the printhead module relative to a carrier, the printer being configured to:
access a correction factor associated with the at least one printhead module;
determine an order in which at least some of the dot data is supplied to at least one of the at least one printhead modules, the order being determined at least partly on the basis of the correction factor, thereby to at least partially compensate for the rotational displacement; and supply the dot data to the printhead module.

381. A printer controller according to claim 362, for supplying dot data to a printhead module having a plurality of nozzles for expelling ink, the printhead module including a plurality of thermal sensors, each of the thermal sensors being configured to respond to a temperature at or adjacent at least one of the nozzles, the printer controller being configured to modify operation of at least some of the nozzles in response to the temperature rising above a first threshold.

382. A printer controller according to claim 362, for controlling a printhead comprising at least one monolithic printhead module, the at least one printhead module having a plurality of rows of nozzles configured to extend, in use, across at least part of a printable pagewidth of the printhead, the nozzles in each row being grouped into at least first and second fire groups, the printhead module being configured to sequentially fire, for each row, the nozzles of each fire group, such that each nozzle in the sequence from each fire group is fired simultaneously with respective corresponding nozzles in the sequence in the other fire groups, wherein the nozzles are fired row by row such that the nozzles of each row are all fired before the nozzles of each subsequent row, wherein the printer controller is configured to provide one or more control signals that control the order of firing of the nozzles.

383. A printer controller according to claim 362, for outputting to a printhead module:
dot data to be printed with at least two different inks; and control data for controlling printing of the dot data;
the printer controller including at least one communication output, each or the communication output being configured to output at least some of the control data and at least some of the dot data for the at least two inks.

384. A printer controller according to claim 362, for supplying data to a printhead module including at least one row of printhead nozzles, at least one row including at least one displaced row portion, the displacement of the row portion including a component in a direction normal to that of a pagewidth to be printed.

385. A printer controller according to claim 362, for supplying print data to at least one printhead module capable of printing a maximum of n of channels of print data, the at least one printhead module being configurable into:
a first mode, in which the printhead module is configured to receive data for a first number of the channels; and a second mode, in which the printhead module is configured to receive print data for a second number of the channels, wherein the first number is greater than the second number;
wherein the printer controller is selectively configurable to supply dot data for the first and second modes.

386. A printer controller according to claim 362, for supplying data to a printhead comprising a plurality of printhead modules, the printhead being wider than a reticle step used in forming the modules, the printhead comprising at least two types of the modules, wherein each type is determined by its geometric shape in plan.

387. A printer controller according to claim 362, for supplying one or more control signals to a printhead module, the printhead module including at least one row that comprises a plurality of sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, such that:
(a). a fire signal is provided to nozzles at a first and nth position in each set of nozzles;
(b), a fire signal is provided to the next inward pair of nozzles in each set;
(c). in the event n is an even number, step (b) is repeated until all of the nozzles in each set has been fired;
and (d). in the event n is an odd number, step (b) is repeated until all of the nozzles but a central nozzle in each set have been fired, and then the central nozzle is fired.

388. A printer controller according to claim 362, for supplying one or more control signals to a printhead module, the printhead module including at least one row that comprises a plurality of adjacent sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, the method comprising providing, for each set of nozzles, a fire signal in accordance with the sequence: [nozzle position 1, nozzle position n, nozzle position 2, nozzle position (n-1), ... , nozzle position x], wherein nozzle position x is at or adjacent the centre of the set of nozzles.

389. A printer controller according to claim 362, for supplying dot data to a printhead module comprising at least first and second rows configured to print ink of a similar type or color, at least some nozzles in the first row being aligned with respective corresponding nozzles in the second row in a direction of intended media travel relative to the printhead, the printhead module being configurable such that the nozzles in the first and second pairs of rows are fired such that some dots output to print media are printed to by nozzles from the first pair of rows and at least some other dots output to print media are printed to by nozzles from the second pair of rows, the printer controller being configurable to supply dot data to the printhead module for printing.

390. A printer controller according to claim 362, for supplying dot data to at least one printhead module, the at least one printhead module comprising a plurality of rows, each of the rows comprising a plurality of nozzles for ejecting ink, wherein the printhead module includes at least first and second rows configured to print ink of a similar type or color, the printer controller being configured to supply the dot data to the at least one printhead module such that, in the event a nozzle in the first row is faulty, a corresponding nozzle in the second row prints an ink dot at a position on print media at or adjacent a position where the faulty nozzle would otherwise have printed it.

391. A printer controller according to claim 362, for receiving first data and manipulating the first data to produce dot data to be printed, the print controller including at least two serial outputs for supplying the dot data to at least one printhead.

392. A printer controller according to claim 362, for supplying data to a printhead module including:
at least one row of print nozzles;
at least first and second shift registers for shifting in dot data supplied from a data source, wherein each shift register feeds dot data to a group of nozzles, and wherein each of the groups of the nozzles is interleaved with at least one of the other groups of the nozzles.

393. A printer controller according to claim 362, for supplying data to a printhead capable of printing a maximum of n of channels of print data, the printhead being configurable into:
a first mode, in which the printhead is configured to receive print data for a first number of the channels; and a second mode, in which the printhead is configured to receive print data for a second number of the channels, wherein the first number is greater than the second number.

394. A printer controller according to claim 362, for supplying data to a printhead comprising a plurality of printhead modules, the printhead being wider than a reticle step used in forming the modules, the printhead comprising at least two types of the modules, wherein each type is determined by its geometric shape in plan.

395. A printer controller according to claim 362, for supplying data to a printhead module including at least one row that comprises a plurality of sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, such that, for each set of nozzles, a fire signal is provided in accordance with the sequence: [nozzle position 1, nozzle position n, nozzle position 2, nozzle position (n-1), ... , nozzle position x], wherein nozzle position x is at or adjacent the centre of the set of nozzles.

396. A printer controller according to claim 362, for supplying data to a printhead module including at least one row that comprises a plurality of adjacent sets of n adjacent nozzles, each of the nozzles being configured to expel the ink in.response to a fire signal, the printhead being configured to output ink from nozzles at a first and nth position in each set of nozzles, and then each next inward pair of nozzles in each set, until:
in the event n is an even number, all of the nozzles in each set has been fired; and in the event n is an odd number, all of the nozzles but a central nozzle in each set have been fired, and then to fire the central nozzle.

397. A printer controller according to claim 362, for supplying data to a printhead module for receiving dot data to be printed using at least two different inks and control data for controlling printing of the dot data, the printhead module including a communication input for receiving the dot data for the at least two colors and the control data.

398. A printer controller according to claim 362, for supplying data to a printhead module including at least one row of printhead nozzles, at least one row including at least one displaced row portion, the displacement of the row portion including a component in a direction normal to that of a pagewidth to be printed.

399. A printer controller according to claim 362, for supplying data to a printhead module having a plurality of rows of nozzles configured to extend, in use, across at least part of a printable pagewidth, the nozzles in each row being grouped into at least first and second fire groups, the printhead module being configured to sequentially fire, for each row, the nozzles of each fire group, such that each nozzle in the sequence from each fire group is fired simultaneously with respective corresponding nozzles in the sequence in the other fire groups, wherein the nozzles are fired row by row such that the nozzles of each row are all fired before the nozzles of each subsequent row.

400. A printer controller according to claim 362, for supplying data to a printhead module comprising at least first and second rows configured to print ink of a similar type or color, at least some nozzles in the first row being aligned with respective corresponding nozzles in the second row in a direction of intended media travel relative to the printhead, the printhead module being configurable such that the nozzles in the first and second pairs of rows are fired such that some dots output to print media are printed to by nozzles from the first pair of rows and at least some other dots output to print media are printed to by nozzles from the second pair of rows.

401. A printer controller according to claim 362, for providing data to a printhead module that includes:
at least one row of print nozzles;
at least first and second shift registers for shifting in dot data supplied from a data source, wherein each shift register feeds dot data to a group of nozzles, and wherein each of the groups of the nozzles is interleaved with at least one of the other groups of the nozzles.

402. A printer controller according to claim 362, for supplying data to a printhead module having a plurality of nozzles for expelling ink, the printhead module including a plurality of thermal sensors, each of the thermal sensors being configured to respond to a temperature at or adjacent at least one of the nozzles, the printhead module being configured to modify operation of the nozzles in response to the temperature rising above a first threshold.

403. A printer controller according to claim 362, for supplying data to a printhead module comprising a plurality of rows, each of the rows comprising a plurality of nozzles for ejecting ink, wherein the printhead module includes at least first and second rows configured to print ink of a similar type or color, and being configured such that, in the event a nozzle in the first row is faulty, a corresponding nozzle in the second row prints an ink dot at a position on print media at or adjacent a position where the faulty nozzle would otherwise have printed it.

404. A printer controller for supplying dot data to at least one printhead module and at least partially compensating for errors in ink dot placement by at least one of a plurality of nozzles on the printhead module due to erroneous rotational displacement of the printhead module relative to a carrier, the printer being configured to:
access a correction factor associated with the at least one printhead module;
determine an order in which at least some of the dot data is supplied to at least one of the at least one printhead modules, the order being determined at least partly on the basis of the correction factor, thereby to at least partially compensate for the rotational displacement; and supply the dot data to the printhead module.

405. A printer controller according to claim 404, wherein the nozzles are disposed in a plurality of rows, and the printer controller is configured to reallocate at least one of the ink dots from at least one original print line to at least one alternate print line, thereby to effect the at least partial compensation.

406. A printer controller according to claim 404, configured to retrieve the correction factor from a memory associated with the printhead.

407. A printer controller according to claim 406, wherein the memory is mounted with the printhead, the printhead being mounted on the print engine.

408. A printer controller according to claim 404, wherein the rotational displacement is roll.

409. A printer controller according to claim 404, wherein the rotational displacement is yaw.

410. A printer controller according to claim 404, the printhead module being one of a plurality of printhead modules mounted on a carrier to form a printhead and the error in ink dot placement being an error relative to ink dots output by one or more of the other printhead modules

411. A printer controller according to claim 404, wherein the printhead module is part of a printhead comprising a plurality of the modules, the printer controller being configured to determine an order in which at least some of the dot data is supplied to a plurality of the printhead modules, the order being determined at least partly on the basis of one or more of the correction factors, thereby to at least partially compensate for the rotational displacement of the plurality of the printheads.

412. A printer controller according to claim 404, wherein the correction factor is at least partially based on a thickness of media being printed on.

413. A printer controller according to claim 412, configured to at least improve first order continuity between ink dots printed by adjacent printhead modules.

414. A print engine including a print controller according to claim 404 and a plurality of the printhead modules that define a printhead, the print engine being configured to compensate for the rotational displacement of at least one of the printhead modules.

415. A print engine according to claim 4042, further including a memory for storing the correction factor in a form accessible to the printer controller.

416. A print engine according to claim 4042, configured to alter a timing of fire signals supplied to at least one of the nozzles on the basis of the correction factor, thereby to further effect the at least partial compensation.

417. A print engine according to claim 4044, configured to supply the altered fire signals are to both reallocated ink dots and non-reallocated ink dots.

418. A print engine according to claim 4042, wherein the printhead is a pagewidth printhead.

419. A printer including a print controller according to claim 404.

420. A printer according to claim 4045, further including a pagewidth printhead comprising a plurality of the printhead modules.

421. A printer controller according to claim 404, for implementing a method of at least partially compensating for errors in ink dot placement by at least one of a plurality of nozzles due to erroneous rotational displacement of a printhead module relative to a carrier, the nozzles being disposed on the printhead module, the method comprising the steps of:
determining the rotational displacement;
determining at least one correction factor that at least partially compensates for the ink dot displacement; and using the correction factor to alter the output of the ink dots to at least partially compensate for the rotational displacement.

422. A printer controller according to claim 404 for implementing a method of expelling ink from a printhead module including at least one row that comprises a plurality of adjacent sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, the method comprising providing, for each set of nozzles, a fire signal in accordance with the sequence: [nozzle position 1, nozzle position n, nozzle position 2, nozzle position (n-1), ... , nozzle position x], wherein nozzle position x is at or adjacent the centre of the set of nozzles.

423. A printer controller according to claim 404, for implementing a method of expelling ink from a printhead module including at least one row that comprises a plurality of sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, the method comprising the steps of:
(a). providing a fire signal to nozzles at a first and nth position in each set of nozzles;
(b). providing a fire signal to the next inward pair of nozzles in each set;
(c). in the event n is an even number, repeating step (b) until all of the nozzles in each set has been fired; and (d). in the event n is an odd number, repeating step (b) until all of the nozzles but a central nozzle in each set have been fired, and then firing the central nozzle.

424. A printer controller according to claim 404, manufactured in accordance with a method of manufacturing a plurality of printhead modules, at least some of which are capable of being combined in pairs to form bilithic pagewidth printheads, the method comprising the step of laying out each of the plurality of printhead modules on a wafer substrate, wherein at least one of the printhead modules is right-handed and at least another is left-handed.

425. A printer controller according to claim 404, for supplying data to a printhead module including:
at least one row of print nozzles;
at least two shift registers for shifting in dot data supplied from a data source to each of the at least one rows, wherein each print nozzle obtains dot data to be fired from an element of one of the shift registers.

426. A printer controller according to claim 404, installed in a printer comprising:
a printhead comprising at least a first elongate printhead module, the at least one printhead module including at least one row of print nozzles for expelling ink; and at least first and second printer controllers configured to receive print data and process the print data to output dot data to the printhead, wherein the first and second printer controllers are connected to a common input of the printhead.

427. A printer controller according to claim 404, installed in a printer comprising:
a printhead comprising first and second elongate printhead modules, the printhead modules being parallel to each other and being disposed end to end on either side of a join region;
at least first and second printer controllers configured to receive print data and process the print data to output dot data to the printhead, wherein the first printer controller outputs dot data only to the first printhead module and the second printer controller outputs dot data only to the second printhead module, wherein the printhead modules are configured such that no dot data passes between them.

428. A printer controller according to claim 404, installed in a printer comprising:
a printhead comprising first and second elongate printhead modules, the printhead modules being parallel to each other and being disposed end to end on either side of a join region, wherein the first printhead module is longer than the second printhead module;
at least first and second printer controllers configured to receive print data and process the print data to output dot data to the printhead, wherein: the first printer controller outputs dot data to both the first printhead module and the second printhead module; and the second printer controller outputs dot data only to the second printhead module.

429. A printer controller according to claim 404, installed in a printer comprising:
a printhead comprising first and second elongate printhead modules, the printhead modules being parallel to each other and being disposed end to end on either side of a join region, wherein the first printhead module is longer than the second printhead module;

at least first and second printer controllers configured to receive print data and process the print data to output dot data for the printhead, wherein: the first printer controller outputs dot data to both the first printhead module and the second controller; and the second printer controller outputs dot data to the second printhead module, wherein the dot data output by the second printer controller includes dot data it generates and at least some of the dot data received from the first printer controller.

430. A printer controller according to claim 404, for supplying dot data to a printhead module having a plurality of nozzles for expelling ink,.the printhead module including a plurality of thermal sensors, each of the thermal sensors being configured to respond to a temperature at or adjacent at least one of the nozzles, the printer controller being configured to modify operation of at least some of the nozzles in response to the temperature rising above a first threshold.

431. A printer controller according to claim 404, for controlling a printhead comprising at least one monolithic printhead module, the at least one printhead module having a plurality of rows of nozzles configured to extend, in use, across at least part of a printable pagewidth of the printhead, the nozzles in each row being grouped into at least first and second fire groups, the printhead module being configured to sequentially fire, for each row, the nozzles of each fire group, such that each nozzle in the sequence from each fire group is fired simultaneously with respective corresponding nozzles in the sequence in the other fire groups, wherein the nozzles are fired row by row such that the nozzles of each row are all fired before the nozzles of each subsequent row, wherein the printer controller is configured to provide one or more control signals that control the order of firing of the nozzles.

432. A printer controller according to claim 404, for outputting to a printhead module:
dot data to be printed with at least two different inks; and control data for controlling printing of the dot data;
the printer controller including at least one communication output, each or the communication output being configured to output at least some of the control data and at least some of the dot data for the at least two inks.

433. A printer controller according to claim 404, for supplying data to a printhead module including at least one row of printhead nozzles, at least one row including at least one displaced row portion, the displacement of the row portion including a component in a direction normal to that of a pagewidth to be printed.

434. A printer controller according to claim 404, for supplying print data to at least one printhead module capable of printing a maximum of n of channels of print data, the at least one printhead module being configurable into:
a first mode, in which the printhead module is configured to receive data for a first number of the channels; and a second mode, in which the printhead module is configured to receive print data for a second number of the channels, wherein the first number is greater than the second number;
wherein the printer controller is selectively configurable to supply dot data for the fust and second modes.

435. A printer controller according to claim 404, for supplying data to a printhead comprising a plurality of printhead modules, the printhead being wider than a reticle step used in forming the modules, the printhead comprising at least two types of the modules, wherein each type is determined by its geometric shape in plan.

436. A printer controller according to claim 404, for supplying one or more control signals to a printhead module, the printhead module including at least one row that comprises a plurality of sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, such that:
(a). a fire signal is provided to nozzles at a first and nth position in each set of nozzles;
(b). a fire signal is provided to the next inward pair of nozzles in each set;
(c). in the event n is an even number, step (b) is repeated until all of the nozzles in each set has been fired;
and (d). in the event n is an odd number, step (b) is repeated until all of the nozzles but a central nozzle in each set have been fired, and then the central nozzle is fired.

437. A printer controller according to claim 404, printheadsupplying one or more control signals to a printhead module, the printhead module including at least one row that comprises a plurality of adjacent sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, the method comprising providing, for each set of nozzles, a fire signal in accordance with the sequence: [nozzle position 1, nozzle position n, nozzle position 2, nozzle position (n-1), ... , nozzle position x], wherein nozzle position x is at or adjacent the centre of the set of nozzles.

438. A printer controller according to claim 404, for supplying dot data to a printhead module comprising at least first and second rows configured to print ink of a similar type or color, at least some nozzles in the first row being aligned with respective corresponding nozzles in the second row in a direction of intended media travel relative to the printhead, the printhead module being configurable such that the nozzles in the first and second pairs of rows are fired such that some dots output to print media are printed to by nozzles from the first pair of rows and at least some other dots output to print media are printed to by nozzles from the second pair of rows, the printer controller being configurable to supply dot data to the printhead module for printing.

439. A printer controller according to claim 404, for supplying dot data to at least one printhead module, the at least one printhead module comprising a plurality of rows, each of the rows comprising a plurality of nozzles for ejecting ink, wherein the printhead module includes at least first and second rows configured to print ink of a similar type or color, the printer controller being configured to supply the dot data to the at least one printhead module such that, in the event a nozzle in the first row is faulty, a corresponding nozzle in the second row prints an ink dot at a position on print media at or adjacent a position where the faulty nozzle would otherwise have printed it.

440. A printer controller according to claim 404, for receiving first data and manipulating the first data to produce dot data to be printed, the print controller including at least two serial outputs for supplying the dot data to at least one printhead.

441. A printer controller according to claim 404, for supplying data to a printhead module including:
at least one row of print nozzles;
at least first and second shift registers for shifting in dot data supplied from a data source, wherein each shift register feeds dot data to a group of nozzles, and wherein each of the groups of the nozzles is interleaved with at least one of the other groups of the nozzles.

442. A printer controller according to claim 404, for supplying data to a printhead capable of printing a maximum of n of channels of print data, the printhead being configurable into:
a first mode, in which the printhead is configured to receive print data for a first number of the channels; and a second mode, in which the printhead is configured to receive print data for a second number of the channels, wherein the first number is greater than the second number.

443. A printer controller according to claim 404, for supplying data to a printhead comprising a plurality of printhead modules, the printhead being wider than a reticle step used in forming the modules, the printhead comprising at least two types of the modules, wherein each type is determined by its geometric shape in plan.

444. A printer controller according to claim 404, for supplying data to a printhead module including at least one row that comprises a plurality of sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, such that, for each set of nozzles, a fire signal is provided in accordance with the sequence: [nozzle position 1, nozzle position n, nozzle position 2, nozzle position (n-1), ... , nozzle position x], wherein nozzle position x is at or adjacent the centre of the set of nozzles.

445. A printer controller according to claim 404, for supplying data to a printhead module including at least one row that comprises a plurality of adjacent sets of n adjacent nozzles, each of the nozzles being configured to expel the ink in response to a fire signal, the printhead being configured to output ink from nozzles at a first and nth position in each set of nozzles, and then each next inward pair of nozzles in each set, until:
in the event n is an even number, all of the nozzles in each set has been fired; and in the event n is an odd number, all of the nozzles but a central nozzle in each set have been fired, and then to fire the central nozzle.

446. A printer controller according to claim 404, for supplying data to a printhead module for receiving dot data to be printed using at least two different inks and control data for controlling printing of the dot data, the printhead module including a communication input for receiving the dot data for the at least two colors and the control data.

447. A printer controller according to claim 404, for supplying data to a printhead module including at least one row of printhead nozzles, at least one row including at least one displaced row portion, the displacement of the row portion including a component in a direction normal to that of a pagewidth to be printed.

448. A printer controller according to claim 404, for supplying data to a printhead module having a plurality of rows of nozzles configured to extend, in use, across at least part of a printable pagewidth, the nozzles in each row being grouped into at least first and second fire groups, the printhead module being configured to sequentially fire, for each row, the nozzles of each fire group, such that each nozzle in the sequence from each fire group is fired simultaneously with respective corresponding nozzles in the sequence in the other fire groups, wherein the nozzles are fired row by row such that the nozzles of each row are all fired before the nozzles of each subsequent row.

449. A printer controller according to claim 404, for supplying data to a printhead module comprising at least first and second rows configured to print ink of a similar type or color, at least some nozzles in the first row being aligned with respective corresponding nozzles in the second row in a direction of intended media travel relative to the printhead, the printhead module being configurable such that the nozzles in the first and second pairs of rows are fired such that some dots output to print media are printed to by nozzles from the first pair of rows and at least some other dots output to print media are printed to by nozzles from the second pair of rows.

450. A printer controller according to claim 404, for providing data to a printhead module that includes:
at least one row of print nozzles;
at least first and second shift registers for shifting in dot data supplied from a data source, wherein each shift register feeds dot data to a group of nozzles, and wherein each of the groups of the nozzles is interleaved with at least one of the other groups of the nozzles.

451. A printer controller according to claim 404, for supplying data to a printhead module having a plurality of nozzles for expelling ink, the printhead module including a plurality of thermal sensors, each of the thermal sensors being configured to respond to a temperature at or adjacent at least one of the nozzles, the printhead module being configured to modify operation of the nozzles in response to the temperature rising above a first threshold.

452. A printer controller according to claim 404, for supplying data to a printhead module comprising a plurality of rows, each of the rows comprising a plurality of nozzles for ejecting ink, wherein the printhead module includes at least first and second rows configured to print ink of a similar type or color, and being configured such that, in the event a nozzle in the first row is faulty, a corresponding nozzle in the second row prints an ink dot at a position on print media at or adjacent a position where the faulty nozzle would otherwise have printed it.

453. A printer controller for supplying dot data to a printhead module having a plurality of nozzles for expelling ink, the printhead module including a plurality of thermal sensors, each of the thermal sensors being configured to respond to a temperature at or adjacent at least one of the nozzles, the printer controller being configured to modify operation of at least some of the nozzles in response to the temperature rising above a first threshold.

454. A printer controller according to claim 453, configured to modify the operation of the nozzles at or adjacent the at least one thermal sensor, such that operation of nozzles not at or adjacent the at least one thermal sensor is not modified.

455. A printer controller according to claim 454, wherein each thermal sensor is associated with a predetermined group of the nozzles, the printer controller being configured to modify operation of the nozzles in the predetermined group for which the temperature has risen above the first threshold.

456. A printer controller according to claim 455, wherein each thermal sensor is associated with a single nozzle.

457. A printer controller according to claim 456, wherein the modification includes the printer controller preventing operation of the nozzle.

458. A printer controller according to claim 457, wherein the modification includes the printer controller preventing operation of the nozzle for a predetermined period.

459. A printer controller according to claim 457, wherein the modification includes the printer controller preventing operation of the nozzle until the temperature drops below a second threshold.

460. A printer controller according to claim 459, wherein the second threshold is lower than the first threshold.

461. A printer controller according to claim 460, wherein the second threshold is the same as the first threshold.

462. "A printer controller according to claim 453, wherein the temperature is not determined explicitly by the at least one thermal sensor or the module.

463. A printer controller according to claim 453, wherein each of the nozzles including a thermal ink ejection mechanism.

464. A printer controller according to claim 463, wherein the thermal sensor comprises at least part of one of the thermal inkjet mechanisms.

465. A printer controller according to claim 464, wherein the thermal sensor comprises a heating element.

466. A printer controller according to claim 465, wherein the thermal sensor determines the temperature by determining a resistance of the heating element.

467. A printer controller according to claim 453, configured to:
receive thermal information from the at least one thermal sensor, determine the modification based on the thermal information; and send control information back to the printhead module, the control information being indicative of the modification to make to the operation of the one or more nozzles.

468. A print engine including a printer controller according to claim 467 and the printhead module, wherein the printhead module further includes a plurality of data latches, the data latches being configured to provide dot data to respective ones of the nozzles, at least some of the data latches being configured to receive thermal signals from respective ones of the thermal sensors during an acquisition period.

469. A print engine according to claim 468, wherein the data latches are configured to form a shift register, the shift register being configured to:
shift the print data in during a print load phase;
sample the signals from the thermal sensors during a temperature load phase;
and shift the thermal signals out to the printer controller during an output phase.

470. A print engine according to claim 469, wherein the output phase coincides with a subsequent print load phase.

471. A print engine according to claim 470, further including logic circuitry configured to perform a bitwise operation on: each thermal signal as it is clocked out of the shift register;
and each piece of dot data to be clocked into the shift register, such that when a thermal signal is indicative of a thermal problem with a nozzle, the logic circuitry prevents loading of data that would cause firing of that nozzle.

472. A print engine according to claim 471, wherein the logic circuitry includes an AND circuit that receives as inputs the dot data and the thermal signal corresponding to the nozzle for which the dot data is intended, an output of the AND circuit being in communication with an input of the shift register.

473. A printer controller according to claim 453, wherein each thermal sensor is associated with a pair of the nozzles.

474. A printer controller according to claim 453, for implementing a method of at least partially compensating for errors in ink dot placement by at least one of a plurality of nozzles due to erroneous rotational displacement of a printhead module relative to a carrier, the nozzles being disposed on the printhead module, the method comprising the steps of:
determining the rotational displacement;
determining at least one correction factor that at least partially compensates for the ink dot displacement; and using the correction factor to alter the output of the ink dots to at least partially compensate for the rotational displacement.

475. A printer controller according to claim 453 for implementing a method of expelling ink from a printhead module including at least one row that comprises a plurality of adjacent sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, the method comprising providing, for each set of nozzles, a fire signal in accordance with the sequence: [nozzle position 1, nozzle position n, nozzle position 2, nozzle position (n-1), ... , nozzle position x], wherein nozzle position x is at or adjacent the centre of the set of nozzles.

476. A printer controller according to claim 453, for implementing a method of expelling ink from a printhead module including at least one row that comprises a plurality of sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, the method comprising the steps of:
(a). providing a fire signal to nozzles at a first and nth position in each set of nozzles;
(b). providing a fire signal to the next inward pair of nozzles in each set;
(c). in the event n is an even number, repeating step (b) until all of the nozzles in each set has been fired; and (d). in the event n is an odd number, repeating step (b) until all of the nozzles but a central nozzle in each set have been fired, and then firing the central nozzle.

477. A printer controller according to claim 453, manufactured in accordance with a method of manufacturing a plurality of printhead modules, at least some of which are capable of being combined in pairs to form bilithic pagewidth printheads, the method comprising the step of laying out each of the plurality of printhead modules on a wafer substrate, wherein at least one of the printhead modules is right-handed and at least another is left-handed.

478. A printer controller according to claim 453, for supplying data to a printhead module including:
at least one row of print nozzles;
at least two shift registers for shifting in dot data supplied from a data source to each of the at least one rows, wherein each print nozzle obtains dot data to be fired from an element of one of the shift registers.

479. A printer controller according to claim 453, installed in a printer comprising:
a printhead comprising at least a first elongate printhead module, the at least one printhead module including at least one row of print nozzles for expelling ink; and at least first and second printer controllers configured to receive print data and process the print data to output dot data to the printhead, wherein the first and second printer controllers are connected to a common input of the printhead.

480. A printer controller according to claim 453, installed in a printer comprising:
a printhead comprising first and second elongate printhead modules, the printhead modules being parallel to each other and being disposed end to end on either side of a join region;
at least first and second printer controllers configured to receive print data and process the print data to output dot data to the printhead, wherein the first printer controller outputs dot data only to the first printhead module and the second printer controller outputs dot data only to the second printhead module, wherein the printhead modules are configured such that no dot data passes between them.

481. A printer controller according to claim 453, installed in a printer comprising:
a printhead comprising first and second elongate printhead modules, the printhead modules being parallel to each other and being disposed end to end on either side of a join region, wherein the first printhead module is longer than the second printhead module;
at least first and second printer controllers configured to receive print data and process the print data to output dot data to the printhead, wherein: the first printer controller outputs dot data to both the first printhead module and the second printhead module; and the second printer controller outputs dot data only to the second printhead module.

482. A printer controller according to claim 453, installed in a printer comprising:

a printhead comprising first and second elongate printhead modules, the printhead modules being parallel to each other and being disposed end to end on either side of a join region, wherein the first printhead module is longer than the second printhead module;
at least first and second printer controllers configured to receive print data and process the print data to output dot data for the printhead, wherein: the first printer controller outputs dot data to both the first printhead module and the second controller; and the second printer controller outputs dot data to the second printhead module, wherein the dot data output by the second printer controller includes dot data it generates and at least some of the dot data received from the first printer controller.

483. A printer controller according to claim 453, for supplying dot data to at least one printhead module and at least partially compensating for errors in ink dot placement by at least one of a plurality of nozzles on the printhead module due to erroneous rotational displacement of the printhead module relative to a carrier, the printer being configured to:
access a correction factor associated with the at least one printhead module;
determine an order in which at least some of the dot data is supplied to at least one of the at least one printhead modules, the order being determined at least partly on the basis of the correction factor, thereby to at least partially compensate for the rotational displacement; and supply the dot data to the printhead module.

484. A printer controller according to claim 453, for controlling a printhead comprising at least one monolithic printhead module, the at least one printhead module having a plurality of rows of nozzles configured to extend, in use, across at least part of a printable pagewidth of the printhead, the nozzles in each row being grouped into at least first and second fire groups, the printhead module being configured to sequentially fire, for each row, the nozzles of each fire group, such that each nozzle in the sequence from each. fire group is fired simultaneously with respective corresponding nozzles in the sequence in the other fire groups, wherein the nozzles are fired row by row such that the nozzles of each row are all fired before the nozzles of each subsequent row, wherein the printer controller is configured to provide one or more control signals that control the order of firing of the nozzles.

485. A printer controller according to claim 453, for outputting to a printhead module:
dot data to be printed with at least two different inks; and control data for controlling printing of the dot data;
the printer controller including at least one communication output, each or the communication output being configured to output at least some of the control data and at least some of the dot data for the at least two inks.

486. A printer controller according to claim 453, for supplying data to a printhead module including at least one row of printhead nozzles, at least one row including at least one displaced row portion, the displacement of the row portion including a component in a direction normal to that of a pagewidth to be printed.

487. A printer controller according.to claim 453, for supplying print data to at least one printhead module capable of printing a maximum of n of channels of print data, the at least one printhead module being configurable into:
a first mode, in which the printhead module is configured to receive data for a first number of the channels; and a second mode, in which the printhead module is configured to receive print data for a second number of the channels, wherein the first number is greater than the second number;
wherein the printer controller is selectively configurable to supply dot data for the first and second modes.

488. A printer controller according to claim 453, for supplying data to a printhead comprising a plurality of printhead modules, the printhead being wider than a reticle step used in forming the modules, the printhead comprising at least two types of the modules, wherein each type is determined by its geometric shape in plan.

489. A printer controller according to claim 453, for supplying one or more control signals to a printhead module, the printhead module including at least one row that comprises a plurality of sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, such that:
(a). a fire signal is provided to nozzles at a first and nth position in each set of nozzles;
(b). a fire signal is provided to the next inward pair of nozzles in each set;
(c). in the event n is an even number, step (b) is repeated until all of the nozzles in each set has been fired;
and (d). in the event n is an odd number, step (b) is repeated until all of the nozzles but a central nozzle in each set have been fired, and then the central nozzle is fired.

490. A printer controller according to claim 453, for supplying one or more control signals to a printhead module, the printhead module including at least one row that comprises a plurality of adjacent sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, the method comprising providing, for each set of nozzles, a fire signal in accordance with the sequence: [nozzle position 1, nozzle position n, nozzle position 2, nozzle position (n-1), ... , nozzle position x], wherein nozzle position x is at or adjacent the centre of the set of nozzles.

491. A printer controller according to claim 453, for supplying dot data to a printhead module comprising at least first and second rows configured to print ink of a similar type or color, at least some nozzles in the first row being aligned with respective corresponding nozzles in the second row in a direction of intended media travel relative to the printhead, the printhead module being configurable such that the nozzles in the first and second pairs of rows are fired such that some dots output to print media are printed to by nozzles from the first pair of rows and at least some other dots output to print media are printed to by nozzles from the second pair of rows, the printer controller being configurable to supply dot data to the printhead module for printing.

492. A printer controller according to claim 453, for supplying dot data to at least one printhead module, the at least one printhead module comprising a plurality of rows, each of the rows comprising a plurality of nozzles for ejecting ink, wherein the printhead module includes at least first and second rows configured to print ink of a similar type or color, the printer controller being configured to supply the dot data to the at least one printhead module such that, in the event a nozzle in the first row is faulty, a corresponding nozzle in the second row prints an ink dot at a position on print media at or adjacent a position where the faulty nozzle would otherwise have printed it.

493. A printer controller according to claim 453, for receiving first data and manipulating the first data to produce dot data to be printed, the print controller including at least two serial outputs for supplying the dot data to at least one printhead.

494. A printer controller according to claim 453, for supplying data to a printhead module including:
at least one row of print nozzles;
at least first and second shift registers for shifting in dot data supplied from a data source, wherein each shift register feeds dot data to a group of nozzles, and wherein each of the groups of the nozzles is interleaved with at least one of the other groups of the nozzles.

495. A printer controller according to claim 453, for supplying data to a printhead capable of printing a maximum of n of channels of print data, the printhead being configurable into:
a first mode, in which the printhead is configured to receive print data for a first number of the channels; and a second mode, in which the printhead is configured to receive print data for a second number of the channels, wherein the first number is greater than the second number.

496. A printer controller according to claim 453, for supplying data to a printhead comprising a plurality of printhead modules, the printhead being wider than a reticle step used in forming the modules, the printhead comprising at least two types of the modules, wherein each type is determined by its geometric shape in plan.

497. A printer controller according to claim 453, for supplying data to a printhead module including at least one row that comprises a plurality of sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, such that, for each set of nozzles, a fire signal is provided in accordance with the sequence: [nozzle position 1, nozzle position n, nozzle position 2, nozzle position (n-1), ... , nozzle position x], wherein nozzle position x is at or adjacent the centre of the set of nozzles.

498. A printer controller according to claim 453, for supplying data to a printhead module including at least one row that comprises a plurality of adjacent sets of n adjacent nozzles, each of the nozzles being configured to expel the ink in response to a fire signal, the printhead being configured to output ink from nozzles at a first and nth position in each set of nozzles, and then each next inward pair of nozzles in each set, until:
in the event n is an even number, all of the nozzles in each set has been fired; and in the event n is an odd number, all of the nozzles but a central nozzle in each set have been fired, and then to fire the central nozzle.

499. A printer controller according to claim 453, for supplying data to a printhead module for receiving dot data to be printed using at least two different inks and control data for controlling printing of the dot data, the printhead module including a communication input for receiving the dot data for the at least two colors and the control data.

500. A printer controller according to claim 453, for supplying data to a printhead module including at least one row of printhead nozzles, at least one row including at least one displaced row portion, the displacement of the row portion including a component in a direction normal to that of a pagewidth to be printed.

501. A printer controller according to claim 453, for supplying data to a printhead module having a plurality of rows of nozzles configured to extend, in use, across at least part of a printable pagewidth, the nozzles in each row being grouped into at least first and second fire groups, the printhead module being configured to sequentially fire, for each row, the nozzles of each fire group, such that each nozzle in the sequence from each fire group is fired simultaneously with respective corresponding nozzles in the sequence in the other fire groups, wherein the nozzles are fired row by row such that the nozzles of each row are all fired before the nozzles of each subsequent row.

502. A printer controller according to claim 453, for supplying data to a printhead module comprising at least first and second rows configured to print ink of a similar type or color, at least some nozzles in the first row being aligned with respective corresponding nozzles in the second row in a direction of intended media travel relative to the printhead, the printhead module being configurable such that the nozzles in the first and second pairs of rows are fired such that some dots output to print media are printed to by nozzles from the first pair of rows and at least some other dots output to print media are printed to by nozzles from the second pair of rows.

503. A printer controller according to claim 453, for providing data to a printhead module that includes:
at least one row of print nozzles;

at least first and second shift registers for shifting in dot data supplied from a data source, wherein each shift register feeds dot data to a group of nozzles, and wherein each of the groups of the nozzles is interleaved with at least one of the other groups of the nozzles.

504. A printer controller according to claim 453, for supplying data to a printhead module having a plurality of nozzles for expelling ink, the printhead module including a plurality of thermal sensors, each of the thermal sensors being configured to respond to a temperature at or adjacent at least one of the nozzles, the printhead module being configured to modify operation of the nozzles in response to the temperature rising above a first threshold.

505. A printer controller according to claim 453, for supplying data to a printhead module comprising a plurality of rows, each of the rows comprising a plurality of nozzles for ejecting ink, wherein the printhead module includes at least first and second rows configured to print ink of a similar type or color, and being configured such that, in the event a nozzle in the first row is faulty, a corresponding nozzle in the second row prints an ink dot at a position on print media at or adjacent a position where the faulty nozzle would otherwise have printed it.

506. A printer controller according to claim 472, further including a logic circuit accepting as inputs a masking signal and the thermal signal corresponding to the nozzle for which the dot data is intended, the logic circuit outputting the thermal signal to the input of the AND circuit in reliance on a value of the masking signal.

507. A printer controller according to claim 506, wherein the value of the masking signal enables masking of the thermal signal for at least one nozzle position, including the nozzle for which the current dot data is intended.

508. A printer controller according to claim 506, wherein the value of the masking signal enables masking of the thermal signal for a plurality of nozzle positions corresponding to a region of the printhead associated the nozzle for which the current dot data is intended.

509. A printer controller according to claim 506, wherein the value of the masking signal enables masking of the thermal signal for all of the nozzle positions of the printhead.

510. A printer controller for controlling a printhead comprising at least one monolithic printhead module, the at least one printhead module having a plurality of rows of nozzles configured to extend, in use, across at least part of a printable pagewidth of the printhead, the nozzles in each row being grouped into at least first and second fire groups, the printhead module being configured to sequentially fire, for each row, the nozzles of each fire group, such that each nozzle in the sequence from each fire group is fired simultaneously with respective corresponding nozzles in the sequence in the other fire groups, wherein the nozzles are fired row by row such that the nozzles of each row are all fired before the nozzles of each subsequent row, wherein the printer controller is configured to provide one or more control signals that control the order of firing of the nozzles.

511. A printer controller according to claim 510, wherein the one or more control signals include a fire control sequence indicative of a first fire group to be fired.

512. A printer controller according to claim 511, the printhead being configured to shift the fire control sequence through a shift register to cause subsequent firing of the second and any other fire groups, wherein the printer controller is configured to provide the fire control sequence during an initiation phase of the printhead, such that the fire control sequence does not need to be repeatedly provided by the printer controller while printing is taking place.

513. A printer controller according to claim 511, the printhead being configured to shift the fire control sequence through a shift register to cause subsequent firing of the second and any other fire groups, wherein the printer controller is configured to provide the fire control sequence periodically during printing.

514. A printer controller according to claim 513, configured to provide the fire control sequence on a per row or per print-line basis.

515. A printer controller according to claim 510, configured to provide a fire enable signal in addition to the one or more fire control signals, such that the combination of the fire enable and fire control signals cause selected ones of the nozzles to fire in the predetermined sequence and in accordance with a predetermined timing.

516. A print engine including a printhead and a printer controller, the printhead comprising at least one monolithic printhead module, the at least one printhead module having a plurality of rows of nozzles configured to extend, in use, across at least part of a printable pagewidth of the printhead, the nozzles in each row being grouped into at least first and second fire groups, the printhead module being configured to sequentially fire, for each row, the nozzles of each fire group, such that each nozzle in the sequence from each fire group is fired simultaneously with respective corresponding nozzles in the sequence in the other fire groups, wherein the nozzles are fired row by row such that the nozzles of each row are all fired before the nozzles of each subsequent row, wherein the printer controller is configured to provide one or more control signals that control the order of firing of the nozzles.

517. A print engine according to claim 516, wherein the one or more control signals include a fire control sequence indicative of a first fire group to be fired.

518. A print engine according to claim 517, the printhead being configured to shift the fire control sequence through a shift register to cause subsequent firing of the second and any other fire groups, wherein the printer controller is configured to provide the fire control sequence during an initiation phase of the printhead, such that the fire control sequence does not need to be repeatedly provided by the printer controller while printing is taking place.

519. A print engine according to claim 517, the printhead being configured to shift the fire control sequence through a shift register to cause subsequent firing of the second and any other fire groups, wherein the printer controller is configured to provide the fire control sequence periodically during printing.

520. A print engine according to claim 513, configured to provide the fire control sequence on a per row or per print-line basis.

521. A print engine according to claim 510, configured to provide a fire enable signal in addition to the one or more fire control signals, such that the combination of the fire enable and fire control signals cause selected ones of the nozzles to fire in the predetermined sequence and in accordance with a predetermined timing.

522. A printer controller according to claim 510, for implementing a method of at least partially compensating for errors in ink dot placement by at least one of a plurality of nozzles due to erroneous rotational displacement of a printhead module relative to a carrier, the nozzles being disposed on the printhead module, the method comprising the steps of:
determining the rotational displacement;
determining at least one correction factor that at least partially compensates for the ink dot displacement; and using the correction factor to alter the output of the ink dots to at least partially compensate for the rotational displacement.

523. A printer controller according to claim 510 for implementing a method of expelling ink from a printhead module including at least one row that comprises a plurality of adjacent sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, the method comprising providing, for each set of nozzles, a fire signal in accordance with the sequence: [nozzle position 1, nozzle position n, nozzle position 2, nozzle position (n-1), ... , nozzle position x], wherein nozzle position x is at or adjacent the centre of the set of nozzles.

524. A printer controller according to claim 510, for implementing a method of expelling ink from a printhead module including at least one row that comprises a plurality of sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, the method comprising the steps of:
providing a fire signal to nozzles at a first and nth position in each set of nozzles;

providing a fire signal to the next inward pair of nozzles in each set;
in the event n is an even number, repeating step (b) until all of the nozzles in each set has been fired; and in the event n is an odd number, repeating step (b) until all of the nozzles but a central nozzle in each set have been fired, and then firing the central nozzle.

525. A printer controller according to claim 510, manufactured in accordance with a method of manufacturing a plurality of printhead modules, at least some of which are capable of being combined in pairs to form bilithic pagewidth printheads, the method comprising the step of laying out each of the plurality of printhead modules on a wafer substrate, wherein at least one of the printhead modules is right-handed and at least another is left-handed.

526. A printer controller according to claim 510, for supplying data to a printhead module including:
at least one row of print nozzles;
at least two shift registers for shifting in dot data supplied from a data source to each of the at least one rows, wherein each print nozzle obtains dot data to be fired from an element of one of the shift registers.

527. A printer controller according to claim 510, installed in a printer comprising:
a printhead comprising at least a first elongate printhead module, the at least one printhead module including at least one row of print nozzles for expelling ink; and at least first and second printer controllers configured to receive print data and process the print data to output dot data to the printhead, wherein the fust and second printer controllers are connected to a common input of the printhead.

528. A printer controller according to claim 510, installed in a printer comprising:
a printhead comprising first and second elongate printhead modules, the printhead modules being parallel to each other and being disposed end to end on either side of a join region;
at least first and second printer controllers configured to receive print data and process the print data to output dot data to the printhead, wherein the first printer controller outputs dot data only to the first printhead module and the second printer controller outputs dot data only to the second printhead module, wherein the printhead modules are configured such that no dot data passes between them.

529. A printer controller according to claim 510, installed in a printer comprising:
a printhead comprising first and second elongate printhead modules, the printhead modules being parallel to each other and being disposed end to end on either side of a join region, wherein the first printhead module is longer than the second printhead module;
at least first and second printer controllers configured to receive print data and process the print data to output dot data to the printhead, wherein: the first printer controller outputs dot data to both the first printhead module and the second printhead module; and the second printer controller outputs dot data only to the second printhead module.

530. A printer controller according to claim 510, installed in a printer comprising:
a printhead comprising first and second elongate printhead modules, the printhead modules being parallel to each other and being disposed end to end on either side of a join region, wherein the first printhead module is longer than the second printhead module;
at least first and second printer controllers configured to receive print data and process the print data to output dot data for the printhead, wherein: the first printer controller outputs dot data to both the first printhead module and the second controller; and the second printer controller outputs dot data to the second printhead module, wherein the dot data output by the second printer controller includes dot data it generates and at least some of the dot data received from the first printer controller.

531. A printer controller according to claim 510, for supplying dot data to at least one printhead module and at least partially compensating for errors in ink dot placement by at least one of a plurality of nozzles on the printhead module due to erroneous rotational displacement of the printhead module relative to a carrier, the printer being configured to:
access a correction factor associated with the at least one printhead module;
determine an order in which at least some of the dot data is supplied to at least one of the at least one printhead modules, the order being determined at least partly on the basis of the correction factor, thereby to at least partially compensate for the rotational displacement; and supply the dot data to the printhead module.

532. A printer controller according to claim 510, for supplying dot data to a printhead module having a plurality of nozzles for expelling ink, the printhead module including a plurality of thermal sensors, each of the thermal sensors being configured to respond to a temperature at or adjacent at least one of the nozzles, the printer controller being configured to modify operation of at least some of the nozzles in response to the temperature rising above a first threshold.

533. A printer controller according to claim 510, for outputting to a printhead module:
dot data to be printed with at least two different inks; and control data for controlling printing of the dot data;
the printer controller including at least one communication output, each or the communication output being configured to output at least some of the control data and at least some of the dot data for the at least two inks.

534. A printer controller according to claim 510, for supplying data to a printhead module including at least one row of printhead nozzles, at least one row including at least one displaced row portion, the displacement of the row portion including a component in a direction normal to that of a pagewidth to be printed.

535. A printer controller according to claim 510, for supplying print data to at least one printhead module capable of printing a maximum of n of channels of print data, the at least one printhead module being configurable into:
a first mode, in which the printhead module is configured to receive data for a first number of the channels; and a second mode, in which the printhead module is configured to receive print data for a second number of the channels, wherein the first number is greater than the second number, wherein the printer controller is selectively configurable to supply dot data for the first and second modes.

536. A printer controller according to claim 510, for supplying data to a printhead comprising a plurality of printhead modules, the printhead being wider than a reticle step used in forming the modules, the printhead comprising at least two types of the modules, wherein each type is determined by its geometric shape in plan.

537. A printer controller according to claim 510, for supplying one or more control signals to a printhead module, the printhead module including at least one row that comprises a plurality of sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, such that:
(a). a fire signal is provided to nozzles at a first and nth position in each set of nozzles;
(b). a fire signal is provided to the next inward pair of nozzles in each set;.
(c). in the event n is an even number, step (b) is repeated until all of the nozzles in each set has been fired;
and (d). in the event n is an odd number, step (b) is repeated until all of the nozzles but a central nozzle in each set have been fired, and then the central nozzle is fired.

538. A printer controller according to claim 510, for supplying one or more control signals to a printhead module, the printhead module including at least one row that comprises a plurality of adjacent sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, the method comprising providing, for each set of nozzles, a fire signal in accordance with the sequence: [nozzle position 1, nozzle position n, nozzle position 2, nozzle position (n-1),... , nozzle position x], wherein nozzle position x is at or adjacent the centre of the set of nozzles.

539. A printer controller according to claim 510, for supplying dot data to a printhead module comprising at least first and second rows configured to print ink of a similar type or color, at least some nozzles in the first row being aligned with respective corresponding nozzles in the second row in a direction of intended media travel relative to the printhead, the printhead module being configurable such that the nozzles in the first and second pairs of rows are fired such that some dots output to print media are printed to by nozzles from the first pair of rows and at least some other dots output to print media are printed to by nozzles from the second pair of rows, the printer controller being configurable to supply dot data to the printhead module for printing.

540. A printer controller according to claim 510, for supplying dot data to at least one printhead module, the at least one printhead module comprising a plurality of rows, each of the rows comprising a plurality of nozzles for ejecting ink, wherein the printhead module includes at least first and second rows configured to print ink of a similar type or color, the printer controller being configured to supply the dot data to the at least one printhead module such that, in the event a nozzle in the first row is faulty, a corresponding nozzle in the second row prints an ink dot at a position on print media at or adjacent a position where the faulty nozzle would otherwise have printed it.

541. A printer controller according to claim 510, for receiving first data and manipulating the first data to produce dot data to be printed, the print controller including at least two serial outputs for supplying the dot data to at least one printhead.

542. A printer controller according to claim 510, for supplying data to a printhead module including:
at least one row of print nozzles;
at least first and second shift registers for shifting in dot data supplied from a data source, wherein each shift register feeds dot data to a group of nozzles, and wherein each of the groups of the nozzles is interleaved with at least one of the other groups of the nozzles.

543. A printer controller according to claim 510, for supplying data to a printhead capable of printing a maximum of n of channels of print data, the printhead being configurable into:
a first mode, in which the printhead is configured to receive print data for a first number of the channels; and a second mode, in which the printhead is configured to receive print data for a second number of the channels, wherein the first number is greater than the second number.

544. A printer controller according to claim 510, for supplying data to a printhead comprising a plurality of printhead modules, the printhead being wider than a reticle step used in forming the modules, the printhead comprising at least two types of the modules, wherein each type is determined by its geometric shape in plan.

545. A printer controller according to claim 510, for supplying data to a printhead module including at least one row that comprises a plurality of sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, such that, for each set of nozzles, a fire signal is provided in accordance with the sequence: [nozzle position 1, nozzle position n, nozzle position 2, nozzle position (n-1), ... , nozzle position x], wherein nozzle position x is at or adjacent the centre of the set of nozzles.

546. A printer controller according to claim 510, for supplying data to a printhead module including at least one row that comprises a plurality of adjacent sets of n adjacent nozzles, each of the nozzles being configured to expel the ink in response to a fire signal, the printhead being configured to output ink from nozzles at a first and nth position in each set of nozzles, and then each next inward pair of nozzles in each set, until:
in the event n is an even number, all of the nozzles in each set has been fired; and in the event n is an odd number, all of the nozzles but a central nozzle in each set have been fired, and then to fire the central nozzle.

547. A printer controller according to claim 510, for supplying data to a printhead module for receiving dot data to be printed using at least two different inks and control data for controlling printing of the dot data, the printhead module including a communication input for receiving the dot data for the at least two colors and the control data.

548. A printer controller according to claim 510, for supplying data to a printhead module including at least one row of printhead nozzles, at least one row including at least one displaced row portion, the displacement of the row portion including a component in a direction normal to that of a pagewidth to be printed.

549. A printer controller according to claim 510, for supplying data to a printhead module having a plurality of rows of nozzles configured to extend, in use, across at least part of a printable pagewidth, the nozzles in each row being grouped into at least first and second fire groups, the printhead module being configured to sequentially fire, for each row, the nozzles of each fire group, such that each nozzle in the sequence from each fire group is fired simultaneously with respective corresponding nozzles in the sequence in the other fire groups, wherein the nozzles are fired row by row such that the nozzles of each row are all fired before the nozzles of each subsequent row.

550. A printer controller according to claim 510, for supplying data to a printhead module comprising at least first and second rows configured to print ink of a similar type or color, at least some nozzles in the first row being aligned with respective corresponding nozzles in the second row in a direction of intended media travel relative to the printhead, the printhead module being configurable such that the nozzles in the first and second pairs of rows are fired such that some dots output to print media are printed to by nozzles from the first pair of rows and at least some other dots output to print media are printed to by nozzles from the second pair of rows.

551. A printer controller according to claim 510, for providing data to a printhead module that includes:
at least one row of print nozzles;

at least first and second shift registers for shifting in dot data supplied from a data source, wherein each shift register feeds dot data to a group of nozzles, and wherein each of the groups of the nozzles is interleaved with at least one of the other groups of the nozzles.

552. A printer controller according to claim 510, for supplying data to a printhead module having. a plurality of nozzles for expelling ink, the printhead module including a plurality of thermal sensors, each of the thermal sensors being configured to respond to a temperature at or adjacent at least one of the nozzles, the printhead module being configured to modify operation of the nozzles in response to the temperature rising above a first threshold.

553. A printer controller according to claim 510, for supplying data to a printhead module comprising a plurality of rows, each of the rows comprising a plurality of nozzles for ejecting ink, wherein the printhead module includes at least first and second rows configured to print ink of a similar type or color, and being configured such that, in the event a nozzle in the first row is faulty, a corresponding nozzle in the second row prints an ink dot at a position on print media at or adjacent a position where the faulty nozzle would otherwise have printed it.

554. A printer controller according to claim 510, wherein the printhead module includes a plurality of pairs of the rows, each pair of rows including an odd row and an even row, the odd and even rows in each pair being offset from each other in both x and y directions relative to an intended direction of print media movement relative to the printhead, the printer controller being configured to control the at least one printhead module to cause firing of at least a plurality of the odd rows prior to firing any of the even rows, or vice versa.

555. A printer controller according to claim 554, wherein all the odd rows are fired before any of the even rows are fired, or vice versa.

556. A printer controller according to claim 554, configured to control the printhead module such that the odd rows, or the even rows, or both, are fired in a predetermined order.

557. A printer controller according to claim 556, configurable such that the predetermined order is selectable from a plurality of predetermined available orders.

558. A printer controller according to claim 554, wherein the predetermined order is sequential.

559. A printer controller according to claim 558, configurable such that the predetermined order can commence at any of a plurality of the rows.

560. A printer controller for outputting to a printhead module:
dot data to be printed with at least two different inks; and control data for controlling printing of the dot data;
the printer controller including at least one communication output, each or the communication output being configured to output at least some of the control data and at least some of the dot data for the at least two inks.

561. A printer controller according to claim 560, wherein the communication output is configured to output the dot data and control data serially.

562. A printer controller according to claim 560, further including a plurality of the communication outputs.

563. A printer controller according to claim 561, further including a plurality of the communication outputs.

564. A print engine comprising a print controller according to claim 560 and a plurality of printhead modules, the printhead modules being disposed end to end for printing a width exceeding that of any of the individual printhead modules, the communications input of each of the printhead modules being connected to a common dot data and control data bus, the common dot data and control data bus being in functional communication with the communication output.

565. A print engine according to claim 564, wherein each module is configured to respond to dot data and control data on the bus only when it is intended for that module.

566. A printer incorporating a print engine according to claim 564.

567. A printer incorporating a print controller according to claim 560.

568. A print engine according to claim 564, wherein the printhead modules together form a pagewidth printhead.

569. A printer according to claim 567, further including a pagewidth printhead comprising a plurality of the printhead modules.

570. A printer controller according to claim 560, for implementing a method of at least partially compensating for errors in ink dot placement by at least one of a plurality of nozzles due to erroneous rotational displacement of a printhead module relative to a carrier, the nozzles being disposed on the printhead module, the method comprising the steps of:
determining the rotational displacement;

determining at least one correction factor that at least partially compensates for the ink dot displacement; and using the correction factor to alter the output of the ink dots to at least partially compensate for the rotational displacement.

571. A printer controller according to claim 560 for implementing a method of expelling ink from a printhead module including at least one row that comprises a plurality of adjacent sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, the method comprising providing, for each set of nozzles, a fire signal in accordance with the sequence: [nozzle position 1, nozzle position n, nozzle position 2, nozzle position (n-1), ... , nozzle position x], wherein nozzle position x is at or adjacent the centre of the set of nozzles.

572. A printer controller according to claim 560, for implementing a method of expelling ink from a printhead module including at least one row that comprises a plurality of sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, the method comprising the steps of:
(a). providing a fire signal to nozzles at a first and nth position in each set of nozzles;
(b). providing a fire signal to the next inward pair of nozzles in each set;
(c). in the event n is an even number, repeating step (b) until all of the nozzles in each set has been fired; and (d). in the event n is an odd number, repeating step (b) until all of the nozzles but a central nozzle in each set have been fired, and then firing the central nozzle.

573. A printer controller according to claim 560, manufactured in accordance with a method of manufacturing a plurality of printhead modules, at least some of which are capable of being combined in pairs to form bilithic pagewidth printheads, the method comprising the step of laying out each of the plurality of printhead modules on a wafer substrate, wherein at least one of the printhead modules is right-handed and at least another is left-handed.

574. A printer controller according to claim 560, for supplying data to a printhead module including:
at least one row of print nozzles;
at least two shift registers for shifting in dot data supplied from a data source to each of the at least one rows, wherein each print nozzle obtains dot data to be fired from an element of one of the shift registers.

575. A printer controller according to claim 560, installed in a printer comprising:
a printhead comprising at least a first elongate printhead module, the at least one printhead module including at least one row of print nozzles for expelling ink; and at least first and second printer controllers configured to receive print data and process the print data to output dot data to the printhead, wherein the first and second printer controllers are connected to a common input of the printhead.

576. A printer controller according to claim 560, installed in a printer comprising:
a printhead comprising fust and second elongate printhead modules, the printhead modules being parallel to each other and being disposed end to end on either side of a join region;
at least first and second printer controllers configured to receive print data and process the print data to output dot data to the printhead, wherein the first printer controller outputs dot data only to the first printhead module and the second printer controller outputs dot data only to the second printhead module, wherein the printhead modules are configured such that no dot data passes between them.

577. A printer controller according to claim 560, installed in a printer comprising:
a printhead comprising first and second elongate printhead modules, the printhead modules being parallel to each other and being disposed end to end on either side of a join region, wherein the first printhead module is longer than the second printhead module;
at least first and second printer controllers configured to receive print data and process the print data to output dot data to the printhead, wherein: the first printer controller outputs dot data to both the first printhead module and the second printhead module; and the second printer controller outputs dot data only to the second printhead module.

578. A printer controller according to claim 560, installed in a printer comprising:
a printhead comprising first and second elongate printhead modules, the printhead modules being parallel to each other and being disposed end to end on either side of a join region, wherein the first printhead module is longer than the second printhead module;
at least first and second printer controllers configured to receive print data and process the print data to output dot data for the printhead, wherein: the fust printer controller outputs dot data to both the fust printhead module and the second controller, and the second printer controller outputs dot data to the second printhead module, wherein the dot data output by the second printer controller includes dot data it generates and at least some of the dot data received from the first printer controller.

579. A printer controller according to claim 560, for supplying dot data to at least one printhead module and at least partially compensating for errors in ink dot placement by at least one of a plurality of nozzles on the printhead module due to erroneous rotational displacement of the printhead module relative to a carrier, the printer being configured to:
access a correction factor associated with the at least one printhead module;
determine an order in which at least. some of the dot data is supplied to at least one of the at least one printhead modules, the order being. determined at least partly on the basis of the correction factor, thereby to at least partially compensate for the rotational displacement; and supply the dot data to the printhead module.

580. A printer controller according to claim 560, for supplying dot data to a printhead module having a plurality of nozzles for expelling ink, the printhead module including a plurality of thermal sensors, each of the thermal sensors being configured to respond to a temperature at or adjacent at least one of the nozzles, the printer controller being configured to modify operation of at least some of the nozzles in response to the temperature rising above a first threshold.

581. A printer controller according to claim 560, for controlling a printhead comprising at least one monolithic printhead module, the at least one printhead module having a plurality of rows of nozzles configured to extend, in use, across at least part of a printable pagewidth of the printhead, the nozzles in each row being grouped into at least first.and second fire groups, the printhead module being configured to sequentially fire, for each row, the nozzles of each fire group, such that each nozzle in the sequence from each fire group is fired simultaneously with respective corresponding nozzles in the sequence in the other fire groups, wherein the nozzles are fired row by row such that the nozzles of each row are all fired before the nozzles of each subsequent row, wherein the printer controller is configured to provide one or more control signals that control the order of firing of the nozzles.

582. A printer controller according to claim 560, for supplying data to a printhead module including at least one row of printhead nozzles, at least one row including at least one displaced row portion, the displacement of the row portion including a component in a direction normal to that of a pagewidth to be printed.

583. A printer controller according to claim 560, for supplying print data to at least one printhead module capable of printing a maximum of n of channels of print data, the at least one printhead module being configurable into:
a first mode, in which the printhead module is configured to receive data for a first number of the channels; and a second mode, in which the printhead module is configured to receive print data for a second number of the channels, wherein the first number is greater than the second number;
wherein the printer controller is selectively configurable to supply dot data for the first and second modes.

584. A printer controller according to claim 560, for supplying data to a printhead comprising a plurality of printhead modules, the printhead being wider than a reticle step used in forming the modules, the printhead comprising at least two types of the modules, wherein each type is determined by its geometric shape in plan.

585. A printer controller according to claim 560, for supplying one or more control signals to a printhead module, the printhead module including at least one row that comprises a plurality of sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, such that:
(a). a fire signal is provided to nozzles at a first and nth position in each set of nozzles;
(b). a fire signal is provided to the next inward pair of nozzles in each set;

(c). in the event n is an even number, step (b) is repeated until all of the nozzles in each set has been fired;
and (d). in the event n is an odd number, step (b) is repeated until all of the nozzles but a central nozzle in each set have been fired, and then the central nozzle is fired.

586. A printer controller according to claim 560, for supplying one or more control signals to a printhead module, the printhead module including at least one row that comprises a plurality of adjacent sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, the method comprising providing, for each set of nozzles, a fire signal in accordance with the sequence: [nozzle position 1, nozzle position n, nozzle position 2, nozzle position (n-1), ... , nozzle position x], wherein nozzle position x is at or adjacent the centre of the set of nozzles.

587. A printer controller according to claim 560, for supplying dot data to a printhead module comprising at least first and second rows configured to print ink of a similar type or color, at least some nozzles in the first row being aligned with respective corresponding nozzles in the second row in a direction of intended media travel relative to the printhead, the printhead module being configurable such that the nozzles in the first and second pairs of rows are fired such that some dots output to print media are printed to by nozzles from the first pair of rows and at least some other dots output to print media are printed to by nozzles from the second pair of rows, the printer controller being configurable to supply dot data to the printhead module for printing.

588. A printer controller according to claim 560, for supplying dot data to at least one printhead module, the at least one printhead module comprising a plurality of rows, each of the rows comprising a plurality of nozzles for ejecting ink, wherein the printhead module includes at least first and second'rows configured to print ink of a similar type or color, the printer controller being configured to supply the dot data to the at least one printhead module such that, in the event a nozzle in the first row is faulty, a corresponding nozzle in the second row prints an ink dot at a position on print media at or adjacent a position where the faulty nozzle would otherwise have printed it.

589. A printer controller according to claim 560, for receiving first data and manipulating the first data to produce dot data to be printed, the print controller including at least two serial outputs for supplying the dot data to at least one printhead.

590. A printer controller according to claim 560, for supplying data to a printhead module including:
at least one row of print nozzles;
at least first and second shift registers for shifting in dot data supplied from a data source, wherein each shift register feeds dot data to a group of nozzles, and wherein each of the groups of the nozzles is interleaved with at least one of the other groups of the nozzles.

591. A printer controller according to claim 560, for supplying data to a printhead capable of printing a maximum of n of channels of print data, the printhead being configurable into:
a first mode, in which the printhead is configured to receive print data for a first number of the channels; and a second mode, in which the printhead is configured to receive print data for a second number of the channels, wherein the first number is greater than the second number.

592. A printer controller according to claim 560, for supplying data to a printhead comprising a plurality of printhead modules, the printhead being wider than a reticle step used in forming the modules, the printhead comprising at least two types of the modules, wherein each type is determined by its geometric shape in plan.

593. A printer controller according to claim 560, for supplying data to a printhead module including at least one row that comprises a plurality of sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, such that, for each set of nozzles, a fire signal is provided in accordance with the sequence: [nozzle position 1, nozzle position n, nozzle position 2, nozzle position (n-1), ... , nozzle position x], wherein nozzle position x is at or adjacent the centre of the set of nozzles.

594. A printer controller according to claim 560, for supplying data to a printhead module including at least one row that comprises a plurality of adjacent sets of n adjacent nozzles, each of the nozzles being configured to expel the ink in response to a fire signal, the printhead being configured to output ink from nozzles at a first and nth position in each set of nozzles, and then each next inward pair of nozzles in each set, until:
in the event n is an even number, all of the nozzles in each set has been fired; and in the event n is an odd number, all of the nozzles but a central nozzle in each set have been fired, and then to fire the central nozzle.

595. A printer controller according to claim 560, for supplying data to a printhead module for receiving dot data to be printed using at least two different inks and control data for controlling printing of the dot data, the printhead module including a communication input for receiving the dot data for the at least two colors and the control data.

596. A printer controller according to claim 560, for supplying data to a printhead module including at least one row of printhead nozzles, at least one row including at least one displaced row portion, the displacement of the row portion including a component in a direction normal to that of a pagewidth to be printed.

597. A printer controller according to claim 560, for supplying data to a printhead module having a plurality of rows of nozzles configured to extend, in use, across at least part of a printable pagewidth, the nozzles in each row being grouped into at least first and second fire groups, the printhead module being configured to sequentially fire, for each row, the nozzles of each fire group, such that each nozzle in the sequence from each fire group is fired simultaneously with respective corresponding nozzles in the sequence in the other fire groups, wherein the nozzles are fired row by row such that the nozzles of each row are all fired before the nozzles of each subsequent row.

598. A printer controller according to claim 560, for supplying data to a printhead module comprising at least fust and second rows configured to print ink of a similar type or color, at least some nozzles in the first row being aligned with respective corresponding nozzles in the second row in a direction of intended media travel relative to the printhead, the printhead module being configurable such that the nozzles in the first and second pairs of rows are fired such that some dots output to print media are printed to by nozzles from the first pair of rows and at least some other dots output to print media are printed to by nozzles from the second pair of rows.

599. A printer controller according to claim 560, for providing data to a printhead module that includes:
at least one row of print nozzles;
at least first and second shift registers for shifting in dot data supplied from a data source, wherein each shift register feeds dot data to a group of nozzles, and wherein each of the groups of the nozzles is interleaved with at least one of the other groups of the nozzles.

600. A printer controller according to claim 560, for supplying data to a printhead module having a plurality of nozzles for expelling ink, the printhead module including a plurality of thermal sensors, each of the thermal sensors being configured to respond to a temperature at or adjacent at least one of the nozzles, the printhead module being configured to modify operation of the nozzles in response to the temperature rising above a first threshold.

601. A printer controller according to claim 560, for supplying data to a printhead module comprising a plurality of rows, each of the rows comprising a plurality of nozzles for ejecting ink, wherein the printhead module includes at least first and second rows configured to print ink of a similar type or color, and being configured such that, in the event a nozzle in the first row is faulty, a corresponding nozzle in the second row prints an ink dot at a position on print media at or adjacent a position where the faulty nozzle would otherwise have printed it.

602. A printer controller for supplying data to a printhead module including at least one row of printhead nozzles, at least one row including at least one displaced row portion, the displacement of the row portion including a component in a direction normal to that of a pagewidth to be printed, the printer controller being configured to control order and timing of the data supplied to the printhead such that the dropped row is compensated for during printing by the printhead module.

603. A printer controller according to claim 602, wherein the displaced row portion is disposed adjacent one end of the printhead module.

604. A printer controller according to claim.602, wherein the printhead module includes a plurality of the rows, wherein each of at least a plurality of the rows includes one of the displaced row portions.

605. A printer controller according to claim 604, wherein the displaced row portions of at least some of the rows are different in length than the displaced row portions of at least some of the other rows.

606. A printer controller according to claim 605, wherein each of the rows has a displaced row portion, and the sizes of the respective displaced row portions increase from row to row in the direction normal to that of the pagewidth to be printed.

607. A printer controller according to claim 602, for supplying supplying the data to a printhead comprising a plurality of the printhead modules.

608. A printer controller according to claim 602 for supplying data to a printhead comprising a plurality of the printhead modules, wherein the displaced row portion of at least one of the printhead modules is disposed adjacent another of the printhead modules.

609. A printer controller according to claim 608, wherein the printhead modules are the same shape and configuration as each other, and are arranged end to end across the intended print width.

610. A printer controller according to claim 608,,the printhead being a pagewidth printhead.

611. A printer controller according to claim 609, the printhead being a pagewidth printhead.

612. A printer controller according to claim 602, for implementing a method of at least partially compensating for errors in ink dot placement by at least one of a plurality of nozzles due to erroneous rotational displacement of a printhead module relative to a carrier, the nozzles being disposed on the printhead module, the method comprising the steps of:
determining the rotational displacement;
determining at least one correction factor that at least partially compensates for the ink dot displacement; and using the correction factor to alter the output of the ink dots to at least partially compensate for the rotational displacement.

613. A printer controller according to claim 602 for implementing a method of expelling ink from a printhead module including at least one row that comprises a plurality of adjacent sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, the method comprising providing, for each set of nozzles, a fire signal in accordance with the sequence: [nozzle position 1, nozzle position n, nozzle position 2, nozzle position (n-1), ... , nozzle position x], wherein nozzle position x is at or adjacent the centre of the set of nozzles.

614. A printer controller according to claim 602, for implementing a method of expelling ink from a printhead module including at least one row that comprises a plurality of sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, the method comprising the steps of:
(a). providing a fire signal to nozzles at a first and nth position in each set of nozzles;
(b). providing a fire signal to the next inward pair of nozzles in each set;
(c). in the event n is an even number, repeating step (b) until all of the nozzles in each set has been fired; and (d). in the event n is an odd number, repeating step (b) until all of the nozzles but a central nozzle in each set have been fired, and then firing the central nozzle.

615. A printer controller according to claim 602, manufactured in accordance with a method of manufacturing a plurality of printhead modules, at least some of which are capable of being combined in pairs to form bilithic pagewidth printheads, the method comprising the step of laying out each of the plurality of printhead modules on a wafer substrate, wherein at least one of the printhead modules is right-handed and at least another is left-handed.

616. A printer controller according to claim 602, for supplying data to a printhead module including:
at least one row of print nozzles;
at least two shift registers for shifting in dot data supplied from a data source to each of the at least one rows, wherein each print nozzle obtains dot data to be fired from an element of one of the shift registers.

617. A printer controller according to claim 602, installed in a printer comprising:
a printhead comprising at least a first elongate printhead module, the at least one printhead module including at least one row of print nozzles for expelling ink; and at least first and second printer controllers configured to receive print data and process the print data to output dot data to the printhead, wherein the first and second printer controllers are connected to a common input of the printhead.

618. A printer controller according to claim 602, installed in a printer comprising:
a printhead comprising first and second elongate printhead modules, the printhead modules being parallel to each other and being disposed end to end on either side of a join region;

at least first and second printer controllers configured to receive print data and process the print data to output dot data to the printhead, wherein the first printer controller outputs dot data only to the first printhead module and the second printer controller outputs dot data only to the second printhead module, wherein the printhead modules are configured such that no dot data passes between them.

619. A printer controller according to claim 602, installed in a printer comprising:
a printhead comprising first and second elongate printhead modules, the printhead modules being parallel to each other and being disposed end to end on either side of a join region, wherein the first printhead module is longer than the second printhead module;
at least first and second printer controllers configured to receive print data and process the print data to output dot data to the printhead, wherein: the first printer controller outputs dot data to both the first printhead module and the second printhead module; and the second printer controller outputs dot data only to the second printhead module.

620. A printer controller according to claim 602, installed in a printer comprising:
a printhead comprising first and second elongate printhead modules, the printhead modules being parallel to each other and being disposed end to end on either side of a join region, wherein the first printhead module is longer than the second printhead module;
at least first and second printer controllers configured to receive print data and process the print data to output dot data for the printhead, wherein: the fust printer controller outputs dot data to both the first printhead module and the second controller, and the second printer controller outputs dot data to the second printhead module, wherein the dot data output by the second printer controller includes dot data it generates and at least some of the dot data received from the first printer controller.

621. A printer controller according to claim 602, for supplying dot data to at least one printhead module and at least partially compensating for errors in ink dot placement by at least one of a plurality of nozzles on the printhead module due to erroneous rotational displacement of the printhead module relative to a carrier, the printer being configured to:
access a correction factor associated with the at least one printhead module;
determine an order in which at least some of the dot data is supplied to at least one of the at least one printhead modules, the order being determined at least partly on the basis of the correction factor, thereby to at least partially compensate for the rotational displacement; and supply the dot data to the printhead module.

622. A printer controller according to claim 602, for supplying dot data to a printhead module having a plurality of nozzles for expelling ink, the printhead module including a plurality of thermal sensors, each of the thermal sensors being configured to respond to a temperature at or adjacent at least one of the nozzles, the printer controller being configured to modify operation of at least some of the nozzles in response to the temperature rising above a first threshold.

623. A printer controller according to claim 602, for controlling a printhead comprising at least one monolithic printhead module, the at least one printhead module having a plurality of rows of nozzles configured to.
extend, in use, across at least part of a printable pagewidth of the printhead, the nozzles in each row being grouped into at least first and second fire groups, the printhead module being configured to sequentially fire, for each row, the nozzles of each fire group, such that each nozzle in the sequence from each fire group is fired simultaneously with respective corresponding nozzles in the sequence in the other fire groups, wherein the nozzles are fired row by row such that the nozzles of each row are all fired before the nozzles of each subsequent row, wherein the printer controller is configured to provide one or more control signals that control the order of firing of the nozzles.

624. A printer controller according to claim 602, for outputting to a printhead module:
dot data to be printed with at least two different inks; and control data for controlling printing of the dot data;
the printer controller including at least one communication output, each or the communication output being configured to output at least some of the control data and at least some of the dot data for the at least two inks.

625. A printer controller according to claim 602, for supplying print data to at least one printhead module capable of printing a maximum of n of channels of print data, the at least one printhead module being configurable into:
a first mode, in which the printhead module is configured to receive data for a first number of the channels; and a second mode, in which the printhead module is configured to receive print data for a second number of the channels, wherein the first number is greater than the second number;
wherein the printer controller is selectively configurable to supply dot data for the first and second modes.

626. A printer controller according to claim 602, for supplying data to a printhead comprising a plurality of printhead modules, the printhead being wider than a reticle step used in forming the modules, the printhead comprising at least two types of the modules, wherein each type is determined by its geometric shape in plan.

627. A printer controller according to claim 602, for supplying one or more control signals to a printhead module, the printhead module including at least one row that comprises a plurality of sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, such that:
(a). a fire signal is provided to nozzles at a first and nth position in each set of nozzles;
(b). a fire signal is provided to the next inward pair of nozzles in each set;

(c). in the event n is an even number, step (b) is repeated until all of the nozzles in each set has been fired;
and (d). in the event n is an odd number, step (b) is repeated until all of the nozzles but a central nozzle in each set have been fired, and then the central nozzle is fired.

628. A printer controller according to claim 602, for supplying one or more control signals to a printhead module, the printhead module including at least one row that comprises a plurality of adjacent sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, the method comprising providing, for each set of nozzles, a fire signal in accordance with the sequence: [nozzle position 1, nozzle position n, nozzle position 2, nozzle position (n-1), ... , nozzle position x], wherein nozzle position x is at or adjacent the centre of the set of nozzles.

629. A printer controller according to claim 602, for supplying dot data to a printhead module comprising at least first and second rows configured to print ink of a similar type or color, at least some nozzles in the first row being aligned with respective corresponding nozzles in the second row in a direction of intended media travel relative to the printhead, the printhead module being configurable such that the nozzles in the first and second pairs of rows are fired such that some dots output to print media are printed to by nozzles from the first pair of rows and at least some other dots output to print media are printed to by nozzles from the second pair of rows, the printer controller being configurable to supply dot data to the printhead module for printing.

630. A printer controller according to claim 602, for supplying dot data to at least one printhead module, the at least one printhead module comprising a plurality of rows, each of the rows comprising a plurality of nozzles for ejecting ink, wherein the printhead module includes at least first and second rows configured to print ink of a similar type or color, the printer controller being configured to supply the dot data to the at least one printhead module such that, in the event a nozzle in the first row is faulty, a corresponding nozzle in the second row prints an ink dot at a position on print media at or adjacent a position where the faulty nozzle would otherwise have printed it.

631. A printer controller according to claim 602, for receiving first data and manipulating the first data to produce dot data to be printed, the print controller including at least two serial outputs for supplying the dot data to at least one printhead.

632. A printer controller according to claim 602, for supplying data to a printhead module including:
at least one row of print nozzles;
at least first and second shift registers for shifting in dot data supplied from a data source, wherein each shift register feeds dot data to a group of nozzles, and wherein each of the groups of the nozzles is interleaved with at least one of the other groups of the nozzles.

633. A printer controller according to claim 602, for supplying data to a printhead capable of printing a maximum of n of channels of print data, the printhead being configurable into:
a first mode, in which the printhead is configured to receive print data for a first number of the channels; and a second mode, in which the printhead is configured to receive print data for a second number of the channels, wherein the first number is greater than the second number.

634. A printer controller according to claim 602, for supplying data to a printhead comprising a plurality of printhead modules, the printhead being wider than a reticle step used in forming the modules, the printhead comprising at least two types of the modules, wherein each type is determined by its geometric shape in plan.

635. A printer controller according to claim 602, for supplying data to a printhead module including at least one row that comprises a plurality of sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, such that, for each set of nozzles, a fire signal is provided in accordance with the sequence: [nozzle position 1, nozzle position n, nozzle position 2, nozzle position (n-1), ... , nozzle position x], wherein nozzle position x is at or adjacent the centre of the, set of nozzles.

636. A printer controller according to claim 602, for supplying data to a printhead module including at least one row that comprises a plurality of adjacent sets of n adjacent nozzles, each of the nozzles being configured to expel the ink in response to a fire signal, the printhead being configured to output ink from nozzles at a first and nth position in each set of nozzles, and then each next inward pair of nozzles in each set, until:
in the event n is an even number, all of the nozzles in each set has been fired; and in the event n is an odd number, all of the nozzles but a central nozzle in each set have been fired, and then to fire the central nozzle.

637. A printer controller according to claim 602, for supplying data to a printhead module for receiving dot data to be printed using at least two different inks and control data for controlling printing of the dot data, the printhead module including a communication input for receiving the dot data for the at least two colors and the control data.

638. A printer controller according to claim 602, for supplying data to a printhead module including at least one row of printhead nozzles, at least one row including at least one displaced row portion, the displacement of the row portion including a component in a direction normal to that of a pagewidth to be printed.

639. A printer controller according to claim 602, for supplying data to a printhead module having a plurality of rows of nozzles configured to extend, in use, across at least part of a printable pagewidth, the nozzles in each row being grouped into at least first and second fire groups, the printhead module being configured to sequentially fire, for each row, the nozzles of each fire group, such that each nozzle in the sequence from each fire group is fired simultaneously with respective corresponding nozzles in the sequence in the other fire groups, wherein the nozzles are fired row by row such that the nozzles of each row are all fired before the nozzles of each subsequent row.

640. A printer controller according to claim 602, for supplying data to a printhead module comprising at least first and second rows configured to print ink of a similar type or color, at least some nozzles in the first row being aligned with respective corresponding nozzles in the second row in a direction of intended media travel relative to the printhead, the printhead module being configurable such that the nozzles in the first and second pairs of rows are fired such that some dots output to print media are printed to by nozzles from the first pair of rows and at least some other dots output to print media are printed to by nozzles from the second pair of rows.

641. A printer controller according to claim 602, for providing data to a printhead module that includes:
at least one row of print nozzles;
at least first and second shift registers for shifting in dot data supplied from a data source, wherein each shift register feeds dot data to a group of nozzles, and wherein each of the groups of the nozzles is interleaved with at least one of the other groups of the nozzles.

642. A printer controller according to claim 602, for supplying data to a printhead module having a plurality of nozzles for expelling ink, the printhead module including a plurality of thermal sensors, each of the thermal sensors being configured to respond to a temperature at or adjacent at least one of the nozzles, the printhead module being configured to modify operation of the nozzles in response to the temperature rising above a first threshold.

643. A printer controller according to claim 602, for supplying data to a printhead module comprising a plurality of rows, each of the rows comprising a plurality of nozzles for ejecting ink, wherein the printhead module includes at least first and second rows configured to print ink of a similar type or color, and being configured such that, in the event a nozzle in the first row is faulty, a corresponding nozzle in the second row prints an ink dot at a position on print media at or adjacent a position where the faulty nozzle would otherwise have printed it.

644. A printer controller for supplying print data to at least one printhead module capable of printing a maximum of n of channels of print data, the at least one printhead module being configurable into:
a first mode, in which the printhead module is configured to receive data for a first number of the channels; and a second mode, in which the printhead module is configured to receive print data for a second number of the channels, wherein the first number is greater than the second number;
wherein the printer controller is selectively configurable to supply dot data for the first and second modes.

645. A printer controller according to claim 644, wherein the first number is n.

646. A printer controller according to claim 644, wherein the first number is less than n.

647. A printer controller according to claim 644, wherein the printhead module being configurable into at least one other mode, in which the at least one printhead module is configured to receive print data for a third number of print channels other than the first and second numbers, the printer controller being selectively configurable to supply the print data for the third number of print channels.

648. A printer controller according to claim 644, wherein n is 4 and the second number is less than 4.

649. A printer controller according to claim 644, wherein n is 5 and the second number is less than 5.

650. A printer controller according to claim 644, wherein n is 6 and the second number is less than 6.

651. A printer controller according to claim 650, wherein the second number is 3, 4 or 5.

652. A print engine including the print controller according to claim 644 and the at least one printhead module.

653. A print engine according to claim 652, wherein the mode is selected based on the contents of a memory associated with the at least one printhead module.

654. A printhead according to claim 652, wherein the memory is a register.

655. A printhead according to claim 652, wherein the register is on an integrated circuit forming part of the print engine.

656. A printer including a printer controller according to claim 644.

657. A printer including a print engine according to claim 652.

658. A printer according to claim 656, including a pagewidth printhead comprising a plurality of the printhead modules of claim 1.

659. A printer controller according to claim 644, for implementing a method of at least partially compensating for errors in ink dot placement by at least one of a plurality of nozzles due to erroneous rotational displacement of a printhead module relative to a carrier, the nozzles being disposed on the printhead module, the method comprising the steps of:
determining the rotational displacement;
determining at least one correction factor that at least partially compensates for the ink dot displacement; and using the correction factor to alter the output of the ink dots to at least partially compensate for the rotational displacement.

660. A printer controller according to claim 644 for implementing a method of expelling ink from a printhead module including at least one row that comprises a plurality of adjacent sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, the method comprising providing, for each set of nozzles, a fire signal in accordance with the sequence: [nozzle position 1, nozzle position n, nozzle position 2, nozzle position (n-1), ... , nozzle position x], wherein nozzle position x is at or adjacent the centre of the set of nozzles.

661. A printer controller according to claim 644, for implementing a method of expelling ink from a printhead module including at least one row that comprises a plurality of sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, the method comprising the steps of:
(a). providing a fire signal to nozzles at a first and nth position in each set of nozzles;
(b). providing a fire signal to the next inward pair of nozzles in each set;
(c). in the event n is an even number, repeating step (b) until all of the nozzles in each set has been fired; and (d). in the event n is an odd number, repeating step (b) until all of the nozzles but a central nozzle in each set have been fired, and then firing the central nozzle.

662. A printer controller according to claim 644, manufactured in accordance with a method of manufacturing a plurality of printhead modules, at least some of which are capable of being combined in pairs to form bilithic pagewidth printheads, the method comprising the step of laying out each of the plurality of printhead modules on a wafer substrate, wherein at least one of the printhead modules is right-handed and at least another is left-handed.

663. A printer controller according to claim 644, for supplying data to a printhead module including:
at least one row of print nozzles;
at least two shift registers for shifting in dot data supplied from a data source to each of the at least one rows, wherein each print nozzle obtains dot data to be fired from an element of one of the shift registers.

664. A printer controller according to claim 644, installed in a printer comprising:

a printhead comprising at least a first elongate printhead module, the at least one printhead module including at least one row of print nozzles for expelling ink; and at least first and second printer controllers configured to receive print data and process the print data to output dot data to the printhead, wherein the first and second printer controllers are connected to a common input of the printhead.

665. A printer controller according to claim 644, installed in a printer comprising:
a printhead comprising first and second elongate printhead modules, the printhead modules being parallel to each other and being disposed end to end on either side of a join region;
at least first and second printer controllers configured to receive print data and process the print data to output dot data to the printhead, wherein the first printer controller outputs dot data only to the first printhead module and the second printer controller outputs dot data only to the second printhead module, wherein the printhead modules are configured such that no dot data passes between them.

666. A printer controller according to claim 644, installed in a printer comprising:
a printhead comprising first and second elongate printhead modules, the printhead modules being parallel to each other and being disposed end to end on either side of a join region, wherein the first printhead module is longer than the second printhead module;
at least first and second printer controllers configured to receive print data and process the print data to output dot data to the printhead, wherein: the first printer controller outputs dot data to both the first printhead module and the second printhead module; and the second printer controller outputs dot data only to the second printhead module.

667. A printer controller according to claim 644, installed in a printer comprising:
a printhead comprising first and second elongate printhead modules, the printhead modules being parallel to each other and being disposed end to end on either side of a join region, wherein the first printhead module is longer than the second printhead module;
at least first and second printer controllers configured to receive print data and process the print data to output dot data for the printhead, wherein: the first printer controller outputs dot data to both the first printhead module and the second controller; and the second printer controller outputs dot data to the second printhead module, wherein the dot data output by the second printer controller includes dot data it generates and at least some of the dot data received from the first printer controller.

668. A printer controller according to claim 644, for supplying dot data to at least one printhead module and at least partially compensating for errors in ink dot placement by at least one of a plurality of nozzles on the printhead module due to erroneous rotational displacement of the printhead module relative to a carrier, the printer being configured to:

access a correction factor associated with the at least one printhead module;
determine an order in which at least some of the dot data is supplied to at least one of the at least one printhead modules, the order being determined at least partly on the basis of the correction factor, thereby to at least partially compensate for the rotational displacement; and supply the dot data to the printhead module.

669. A printer controller according to claim 644, for supplying dot data to a printhead module having a plurality of nozzles for expelling ink, the printhead module including a plurality of thermal sensors, each of the thermal sensors being configured to respond to a temperature at or adjacent at least one of the nozzles, the printer controller being configured to modify operation of at least some of the nozzles in response to the temperature rising above a first threshold.

670. A printer controller according to claim 64, for controlling a printhead comprising at least one monolithic printhead module, the at least one printhead module having a plurality of rows of nozzles configured to extend, in use, across at least part of a printable pagewidth of the printhead, the nozzles in each row being grouped into at least first and second fire groups, the printhead module being configured to sequentially fire, for each row, the nozzles of each fire group, such that each nozzle in the sequence from each fire group is fired simultaneously with respective corresponding nozzles in the sequence in the other fire groups, wherein the nozzles are fired row by row such that the nozzles of each row are all fired before the nozzles of each subsequent row, wherein the printer controller is configured to provide one or more control signals that control the order of firing of the nozzles.

671. A printer controller according to claim 644, for outputting to a printhead module:
dot data to be printed with at least two different inks; and control data for controlling printing of the dot data;
the printer controller including at least one communication output, each or the communication output being configured to output at least some of the control data and at least some of the dot data for the at least two inks.

672. A printer controller according to claim 644, for supplying data to a printhead module including at least one row of printhead nozzles, at least one row including at least one displaced row portion, the displacement of the row portion including a component in a direction normal to that of a pagewidth to be printed.

673. A printer controller according to claim 644, for supplying data to a printhead comprising a plurality of printhead modules, the printhead being wider than a reticle step used in forming the modules, the printhead comprising at least two types of the modules, wherein each type is determined by its geometric shape in plan.

674. A printer controller according to claim 644, for supplying one or more control signals to a printhead module, the printhead module including at least one row that comprises a plurality of sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, such that:
(a). a fire signal is provided to nozzles at a first and nth position in each set of nozzles;
(b). a fire signal is provided to the next inward pair of nozzles in each set;
(c). in the event n is an even number, step (b) is repeated until all of the nozzles in each set has been fired;
and (d). in the event n is an odd number, step (b) is repeated until all of the nozzles but a central nozzle in each set have been fired, and then the central nozzle is fired.

675. A printer controller according to claim 644, for supplying one or more control signals to a printhead module, the printhead module including at least one row that comprises a plurality of adjacent sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, the method comprising providing, for each set of nozzles, a fire signal in accordance with the sequence: [nozzle position 1, nozzle position n, nozzle position 2, nozzle position (n-1), ... , nozzle position x], wherein nozzle position x is at or adjacent the centre of the set of nozzles.

676. A printer controller according to claim 644, for supplying dot data to a printhead module comprising at least first and second rows configured to print ink of a similar type or color, at least some nozzles in the first row being aligned with respective corresponding nozzles in the second row in a direction of intended media travel relative to the printhead, the printhead module being configurable such that the nozzles in the first and second pairs of rows are fired such that some dots output to print media are printed to by nozzles from the first pair of rows and at least some other dots output to print media are printed to by nozzles from the second pair of rows, the printer controller being configurable to supply dot data to the printhead module for printing.

677. A printer controller according to claim 644, for supplying dot data to at least one printhead module, the at least one printhead module comprising a plurality of rows, each of the rows comprising a plurality of nozzles for ejecting ink, wherein the printhead module includes at least first and second rows configured to print ink of a similar type or color, the printer controller being configured to supply the dot data to the at least one printhead module such that, in the event a nozzle in the first row is faulty, a corresponding nozzle in the second row prints an ink dot at a position on print media at or adjacent a position where the faulty nozzle would otherwise have printed it.

678. A printer controller according to claim 644, for receiving first data and manipulating the first data to produce dot data to be printed, the print controller including at least two serial outputs for supplying the dot data to at least one printhead.

679. A printer controller according to claim 644, for supplying data to a printhead module including:
at least one row of print nozzles;
at least first and second shift registers for shifting in dot data supplied from a data source, wherein each shift register feeds dot data to a group of nozzles, and wherein each of the groups of the nozzles is interleaved with at least one of the other groups of the nozzles.

680. A printer controller according to claim 644, for supplying data to a printhead capable of printing a maximum of n of channels of print data, the printhead being configurable into:
a first mode, in which the printhead is configured to receive print data for a first number of the channels; and a second mode, in which the printhead is configured to receive print data for a second number of the channels, wherein the first number is greater than the second number.

681. A printer controller according to claim 644, for supplying data to a printhead comprising a plurality of printhead modules, the printhead being wider than a reticle step used in forming the modules, the printhead comprising at least two types of the modules, wherein each type is determined by its geometric shape in plan.

682. A printer controller according to claim 644, for supplying data to a printhead module including at least one row that comprises a plurality of sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, such that, for each set of nozzles, a fire signal is provided in accordance with the sequence: [nozzle position 1, nozzle position n, nozzle position 2, nozzle position (n-1), ... , nozzle position x], wherein nozzle position x is at or adjacent the centre of the set of nozzles.

683. A printer controller according to claim 644, for supplying data to a printhead module including at least one row that comprises a plurality of adjacent sets of n adjacent nozzles, each of the nozzles being configured to expel the ink in response to a fire signal, the printhead being configured to output ink from nozzles at a first and nth position in each set of nozzles, and then each next inward pair of nozzles in each set, until:
in the event n is an even number, all of the nozzles in each set has been fired; and in the event n is an odd number, all of the nozzles but a central nozzle in each set have been fired, and then to fire the central nozzle.

684. A printer controller according to claim 644, for supplying data to a printhead module for receiving dot data to be printed using at least two different inks and control data for controlling printing of the dot data, the printhead module including a communication input for receiving the dot data for the at least two colors and the control data.

685. A printer controller according to claim 644, for supplying data to a printhead module including at least one row of printhead nozzles, at least one row including at least one displaced row portion, the displacement of the row portion including a component in a direction normal to that of a pagewidth to be printed.

686. A printer controller according to claim 644, for supplying data to a printhead module having a plurality of rows of nozzles configured to extend, in use, across at least part of a printable pagewidth, the nozzles in each row being grouped into at least first and second fire groups, the printhead module being configured to sequentially fire, for each row, the nozzles of each fire group, such that each nozzle in the sequence from each fire group is fired simultaneously with respective corresponding nozzles in the sequence in the other fire groups, wherein the nozzles are fired row by row such that the nozzles of each row are all fired before the nozzles of each subsequent row.

687. A printer controller according to claim 644, for supplying data to a printhead module comprising at least first and second rows configured to print ink of a similar type or color, at least some nozzles in the first row being aligned with respective corresponding nozzles in the second row in a direction of intended media travel relative to the printhead, the printhead module being configurable such that the nozzles in the first and second pairs of rows are fired such that some dots output to print media are printed to by nozzles from the first pair of rows and at least some other dots output to print media are printed to by nozzles from the second pair of rows.

688. A printer controller according to claim 644, for providing data to a printhead module that includes:
at least one row of print nozzles;
at least first and second shift registers for shifting in dot data supplied from a data source, wherein each shift register feeds dot data to a group of nozzles, and wherein each of the groups of the nozzles is interleaved with at least one of the other groups of the nozzles.

689. A printer controller according to claim 644, for supplying data to a printhead module having a plurality of nozzles for expelling ink, the printhead module including a plurality of thermal sensors, each of the thermal sensors being configured to respond to a temperature at or adjacent at least one of the nozzles, the printhead module being configured to modify operation of the nozzles in response to the temperature rising above a first threshold.

690. A printer controller according to claim 644, for supplying data to a printhead module comprising a plurality of rows, each of the rows comprising a plurality of nozzles for ejecting ink, wherein the printhead module includes at least first and second rows configured to print ink of a similar type or color, and being configured such that, in the event a nozzle in the first row is faulty, a corresponding nozzle in the second row prints an ink dot at a position on print media at or adjacent a position where the faulty nozzle would otherwise have printed it.

691. A printer controller for supplying data to a printhead comprising a plurality of printhead modules, the printhead being wider than a reticle step used in forming the modules, the printhead comprising at least two types of the modules, wherein each type is determined by its geometric shape in plan.

692. A printer controller according to claim 691, wherein the printhead comprises a plurality of at least one of the types of module.

693. A printer controller according to claim 692, wherein the printhead comprises a plurality of each of at least two of the types of module.

694. A printer controller according to claim 691, wherein the printhead comprises two types of the module.

695. A printer controller according to claim 694, wherein the two types of module alternate across a print width of the printhead.

696. A printer controller according to claim 691, each of the modules including at least one row of print nozzles, wherein each of the at least one row of print nozzles includes at least a portion that extends at an acute angle to an intended relative direction of movement between the printhead and print media.

697. A printer controller according to claim 696, wherein the different types of modules are configured, and arranged relative to each other, such that there is substantially no growth in offset of each of the at least one row of print nozzles in a direction across an intended print width of the printhead.

A printer controller according to claim 691, wherein each of the printhead modules is a monolithic integrated circuit.

699. A printer controller according to claim 691, each of the modules including at least one row of print nozzles, wherein each of the at least one rows includes at least two sub-rows, each of the sub-rows being parallel to each other and displaced relative to each other in a direction of intended movement of print media relative to the printhead.

700. A printer controller according to claim 691, wherein at least one row in each of the printhead modules prints an ink corresponding to at least one row on an adjacent printhead module, wherein the corresponding rows of at least two of the different printhead modules are offset from each other in a direction of intended movement of print media relative to the printhead,

701. A printer controller according to claim 691, the printhead being a pagewidth printhead.

702. A printer controller according to claim 697, the printhead being a pagewidth printhead.

703. A printer controller according to claim 702, the printhead being a pagewidth printhead.

704. A printer controller according to claim 691, for implementing a method of at least partially compensating for errors in ink dot placement by at least one of a plurality of nozzles due to erroneous rotational displacement of a printhead module relative to a carrier, the nozzles being disposed on the printhead module, the method comprising the steps of:
determining the rotational displacement;
determining at least one correction factor that at least partially compensates for the ink dot displacement; and using the correction factor to alter the output of the ink dots to at least partially compensate for the rotational displacement.

705. A printer controller according to claim 691 for implementing a method of expelling ink from a printhead.
module including at least one row that comprises a plurality of adjacent sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, the method comprising providing, for each set of nozzles, a fire signal in accordance with the sequence: [nozzle position 1, nozzle position n, nozzle position 2, nozzle position (n-1), ... , nozzle position x], wherein nozzle position x is at or adjacent the centre of the set of nozzles.

706. A printer controller according to claim 691, for implementing a method of expelling ink from a printhead module including at least one row that comprises a plurality of sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, the method comprising the steps of:
(a). providing a fire signal to nozzles at a first and nth position in each set of nozzles;
(b). providing a fire signal to the next inward pair of nozzles in each set;
(c). in the event n is an even number, repeating step (b) until all of the nozzles in each set has been fired; and (d). in the event n is an odd number, repeating step (b) until all of the nozzles but a central nozzle in each set have been fired, and then firing the central nozzle.

707. A printer controller according to claim 691, manufactured in accordance with a method of manufacturing a plurality of printhead modules, at least some of which are capable of being combined in pairs to form bilithic pagewidth printheads, the method comprising the step of laying out each of the plurality of printhead modules on a wafer substrate, wherein at least one of the printhead modules is right-handed and at least another is left-handed.

708. A printer controller according to claim 691, for supplying data to a printhead module including:
at least one row of print nozzles;
at least two shift registers for shifting in dot data supplied from a data source to each of the at least one rows, wherein each print nozzle obtains dot data to be fired from an element of one of the shift registers.

709. A printer controller according to claim 691, installed in a printer comprising:
a printhead comprising at least a first elongate printhead module, the at least one printhead module including at least one row of print nozzles for expelling ink; and at least first and second printer controllers configured to receive print data and process the print data to output dot data to the printhead, wherein the first and second printer controllers are connected to a common input of the printhead.

710. A printer controller according to claim 691, installed in a printer comprising:
a printhead comprising first and second elongate printhead modules, the printhead modules being parallel to each other and being disposed end to end on either side of a join region;
at least first and second printer controllers configured to receive print data and process the print data to output dot data to the printhead, wherein the first printer controller outputs dot data only to the first printhead module and the second printer controller outputs dot data only to the second printhead module, wherein the printhead modules are configured such that no dot data passes between them.

711. A printer controller according to claim 691, installed in a printer comprising:
a printhead comprising first and second elongate printhead modules, the printhead modules being parallel to each other and being disposed end to end on either side of a join region, wherein the first printhead module is longer than the second printhead module;
at least first and second printer controllers configured to receive print data and process the print data to output dot data to the printhead, wherein: the first printer controller outputs dot data to both the first printhead module and the second printhead module; and the second printer controller outputs dot data only to the second printhead module.

712. A printer controller according to claim 691, installed in a printer comprising:
a printhead comprising first and second elongate printhead modules, the printhead modules being parallel to each other and being disposed end to end on either side of a join region, wherein the first printhead module is longer than the second printhead module;
at least first and second printer controllers configured to receive print data and process the print data to output dot data for the printhead, wherein: the fust printer controller outputs dot data to both the first printhead module and the second controller; and the second printer controller outputs dot data to the second printhead module, wherein the dot data output by the second printer controller includes dot data it generates and at least some of the dot data received from the first printer controller.

713. A printer controller according to claim 691, for supplying dot data to at least one printhead module and at least partially compensating for errors in ink dot placement by at least one of a plurality of nozzles on the printhead module due to erroneous rotational displacement of the printhead module relative to a carrier, the printer being configured to:
access a correction factor associated with the at least one printhead module;
determine an order in which at least some of the dot data is supplied to at least one of the at least one printhead modules, the order being determined at least partly on the basis of the correction factor, thereby to at least partially compensate for the rotational displacement; and supply the dot data to the printhead module.

714. A printer controller according to claim 691, for supplying dot data to a printhead module having a plurality of nozzles for expelling ink, the printhead module including a plurality of thermal sensors, each of the thermal sensors being configured to respond to a temperature at or adjacent at least one of the nozzles, the printer controller being configured to modify operation of at least some of the nozzles in response to the temperature rising above a first threshold.

715. A printer controller according to claim 691, for controlling a printhead comprising at least one monolithic printhead module, the at least one printhead module having a plurality of rows of nozzles configured to extend, in use, across at least part of a printable pagewidth of the printhead, the nozzles in each row being grouped into at least first and second fire groups, the printhead module being configured to sequentially fire, for each row, the nozzles of each fire group, such that each nozzle in the sequence from each fire group is fired simultaneously with respective corresponding nozzles in the sequence in the other fire groups, wherein the nozzles are fired row by row such that the nozzles of each row are all fired before the nozzles of each subsequent row, wherein the printer controller is configured to provide one or more control signals that control the order of firing of the nozzles.

716. A printer controller according to claim 691, for outputting to a printhead module:
dot data to be printed with at least two different inks; and control data for controlling printing of the dot data;
the printer controller including at least one communication output, each or the communication output being configured to output at least some of the control data and at least some of the dot data for the at least two inks.

717. A printer controller according to claim 691, for supplying data to a printhead module including at least one row of printhead nozzles, at least one row including at least one displaced row portion, the displacement of the row portion including a component in a direction normal to that of a pagewidth to be printed.

718. A printer controller according to claim 691, for supplying print data to at least one printhead module capable of printing a maximum of n of channels of print data, the at least one printhead module being configurable into:
a first mode, in which the printhead module is configured to receive data for a first number of the channels; and a second mode, in which the printhead module is configured to receive print data for a second number of the channels, wherein the first number is greater than the second number;
wherein the printer controller is selectively configurable to supply dot data for the first and second modes.

719. A printer controller according to claim 691, for supplying one or more control signals to a printhead module, the printhead module including at least one row that comprises a plurality of sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, such that:
(a). a fire signal is provided to nozzles at a first and nth position in each set of nozzles;
(b). a fire signal is provided to the next inward pair of nozzles in each set;
(c). in the event n is an even number, step (b) is repeated until all of the nozzles in each set has been fired;
and (d). in the event n is an odd number, step (b) is repeated until all of the nozzles but a central nozzle in each set have been fired, and then the central nozzle is fired.

720. A printer controller according to claim 691, for supplying one or more control signals to a printhead module, the printhead module including at least one row that comprises a plurality of adjacent sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, the method comprising providing, for each set of nozzles, a fire signal in accordance with the sequence: [nozzle position 1, nozzle position n, nozzle position 2, nozzle position (n-1), ... , nozzle position x], wherein nozzle position x is at or adjacent the centre of the set of nozzles.

721. A printer controller according to claim 691, for supplying dot data to a printhead module comprising at least first and second rows configured to print ink of a similar type or color, at least some nozzles in the first row being aligned with respective corresponding nozzles in the second row in a direction of intended media travel relative to the printhead, the printhead module being configurable such that the nozzles in the first and second pairs of rows are fired such that some dots output to print media are printed to by nozzles from the first pair of rows and at least some other dots output to print media are printed to by nozzles from the second pair of rows, the printer controller being configurable to supply dot data to the printhead module for printing.

722. A printer controller according to claim 691, for supplying dot data to at least one printhead module, the at least one printhead module comprising a plurality of rows, each of the rows comprising a plurality of nozzles for ejecting ink, wherein the printhead module includes at least first and second rows configured to print ink of a similar type or color, the printer controller being configured to supply the dot data to the at least one printhead module such that, in the event a nozzle in the first row is faulty, a corresponding nozzle in the second row prints an ink dot at a position on print media at or adjacent a position where the faulty nozzle would otherwise have printed it.

723. A printer controller according to claim 691, for receiving first data and manipulating the first data to produce dot data to be printed, the print controller including at least two serial outputs for supplying the dot data to at least one printhead.

724. A printer controller according to claim 691, for supplying data to a printhead module including:
at least one row of print nozzles;
at least first and second shift registers for shifting in dot data supplied from a data source, wherein each shift register feeds dot data to a group of nozzles, and wherein each of the groups of the nozzles is interleaved with at least one of the other groups of the nozzles.

725. A printer controller according to claim 691, for supplying data to a printhead capable of printing a maximum of n of channels of print data, the printhead being configurable into:
a first mode, in which the printhead is configured to receive print data for a first number of the channels; and a second mode, in which the printhead is configured to receive print data for a second number of the channels, wherein the first number is greater than the second number.

726. A printer controller according to claim 691, for supplying data to a printhead comprising a plurality of printhead modules, the printhead being wider than a reticle step used in forming the modules, the printhead comprising at least two types of the modules, wherein each type is determined by its geometric shape in plan.

727. A printer controller according to claim 691, for supplying data to a printhead module including at least one row that comprises a plurality of sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, such that, for each set of nozzles, a fire signal is provided in accordance with the sequence: [nozzle position 1, nozzle position n, nozzle position 2, nozzle position (n-1), ... , nozzle position x], wherein nozzle position x is at or adjacent the centre of the set of nozzles.

728. A printer controller according to claim 691, for supplying data to a printhead module including at least one row that comprises a plurality of adjacent sets of n adjacent nozzles, each of the nozzles being configured to expel the ink in response to a fire signal, the printhead being configured to output ink from nozzles at a first and nth position in each set of nozzles, and then each next inward pair of nozzles in each set, until:
in the event n is an even number, all of the nozzles in each set has been fired; and in the event n is an odd number, all of the nozzles but a central nozzle in each set have been fired, and then to fire the central nozzle.

729. A printer controller according to claim 691, for supplying data to a printhead module for receiving dot data to be printed using at least two different inks and control data for controlling printing of the dot data, the printhead module including a communication input for receiving the dot data for the at least two colors and the control data.

730. A printer controller according to claim 691, for supplying data to a printhead module including at least one row of printhead nozzles, at least one row including at least one displaced row portion, the displacement of the row portion including a component in a direction normal to that of a pagewidth to be printed.

731. A printer controller according to claim 691, for supplying data to a printhead module having a plurality of rows of nozzles configured to extend, in use, across at least part of a printable pagewidth, the nozzles in each row being grouped into at least first and second fire groups, the printhead module being configured to sequentially fire, for each row, the nozzles of each fire group, such that each nozzle in the sequence from each fire group is fired simultaneously with respective corresponding nozzles in the sequence in the other fire groups, wherein the nozzles are fired row by row such that the nozzles of each row are all, fired before the nozzles of each subsequent row.

732. A printer controller according to claim 691, for supplying data to a printhead module comprising at least first and second rows configured to print ink of a similar type or color, at least some nozzles in the fust row being aligned with respective corresponding nozzles in the second row in a direction of intended media travel relative to the printhead, the printhead module being configurable such that the nozzles in the first and second pairs of rows are fired such that some dots output to print media are printed to by nozzles from the first pair of rows and at least some other dots output to print media are printed to by nozzles from the second pair of rows.

733. A printer controller according to claim 691, for providing data to a printhead module that includes:
at least one row of print nozzles;
at least first and second shift registers for shifting in dot data supplied from a data source, wherein each shift register feeds dot data to a group of nozzles, and wherein each of the groups of the nozzles is interleaved with at least one of the other groups of the nozzles.

734. A printer controller according to claim 691, for supplying data to a printhead module having a plurality of nozzles for expelling ink, the printhead module including a plurality of thermal sensors, each of the thermal sensors being configured to respond to a temperature at or adjacent at least one of the nozzles, the printhead module being configured to modify operation of the nozzles in response to the temperature rising above a first threshold.

735. A printer controller according to claim 691, for supplying data to a printhead module comprising a plurality of rows, each of the rows comprising a plurality of nozzles for ejecting ink, wherein the printhead module includes at least first and second rows configured to print ink of a similar type or color, and being configured such that, in the event a nozzle in the first row is faulty, a corresponding nozzle in the second row prints an ink dot at a position on print media at or adjacent a position where the faulty nozzle would otherwise have printed it.

736. A printer controller for supplying one or more control signals to a printhead module, the printhead module including at least one row that comprises a plurality of sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, such that:
(a). a fire signal is provided to nozzles at a first and nth position in each set of nozzles;
(b). a fire signal is provided to the next inward pair of nozzles in each set;
(c). in the event n is an even number, step (b) is repeated until all of the nozzles in each set has been fired;
and (d). in the event n is an odd number, step (b) is repeated until all of the nozzles but a central nozzle in each set have been fired, and then the central nozzle is fired.

737. A printer controller according to claim 736, wherein the printhead module includes a plurality of the rows of nozzles, the printer controller being configured to control the printhead module such that steps (a) to (d) are repeated for each of the rows of nozzles.

738. A printer controller according to claim 737, wherein the rows are disposed in pairs.

739. A printer controller according to claim 738, wherein the rows in each pair of rows are offset relative to each other.

740. A printer controller according to claim 739, wherein each pair of rows is configured to print the same color ink.

741. A printer controller according to claim 740, wherein each pair of rows is connected to a common ink source.

742. A printer controller according to claim 736, wherein the sets of nozzles are adjacent each other.

743. A printer controller according to claim 736, wherein the sets of nozzles are separated by an intermediate nozzle, the intermediate nozzle being fired either prior to the nozzle at position 1 in each set, or following the nozzle at position n.

744. A printer controller according to claim 736, wherein the printhead module is one of a plurality of printhead modules that form a pagewidth printhead, the printer controller being configure to supply the control signals to at least a plurality of the printhead modules.

745. A printer controller according to claim 736, for implementing a method of at least partially compensating for errors in ink dot placement by at least one of a plurality of nozzles due to erroneous rotational displacement of a printhead module relative to a carrier, the nozzles being disposed on the printhead module, the method comprising the steps of:
determining the rotational displacement;
determining at least one correction factor that at least partially compensates for the ink dot displacement; and using the correction factor to alter the output of the ink dots to at least partially compensate for the rotational displacement.

746. A printer controller according to claim 736 for implementing a method of expelling ink from a printhead module including at least one row that comprises a plurality of adjacent sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, the method comprising providing, for each set of nozzles, a fire signal in accordance with the sequence: [nozzle position 1, nozzle position n, nozzle position 2, nozzle position (n-1), ... , nozzle position x], wherein nozzle position x is at or adjacent the centre of the set of nozzles.

747. A printer controller according to claim 736, for implementing a method of expelling ink from a printhead module including at least one row that comprises a plurality of sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, the method comprising the steps of (a). providing a fire signal to nozzles at a first and nth position in each set of nozzles;
(b). providing a fire signal to the next inward pair of nozzles in each set;
(c). in the event n is an even number, repeating step (b) until all of the nozzles in each set has been fired; and (d). in the event n is an odd number, repeating step (b) until all of the nozzles but a central nozzle in each set have been fired, and then firing the central nozzle.

748. A printer controller according to claim 736, manufactured in accordance with a method of manufacturing a plurality of printhead modules, at least some of which are capable of being combined in pairs to form bilithic pagewidth printheads, the method comprising the step of laying out each of the plurality of printhead modules on a wafer substrate, wherein at least one of the printhead modules is right-handed and at least another is left-handed.

749. A printer controller according to claim 736, for supplying data to a printhead module including:
at least one row of print nozzles;
at least two shift registers for shifting in dot data supplied from a data source to each of the at least one rows, wherein each print nozzle obtains dot data to be fired from an element of one of the shift registers.

750. A printer controller according to claim 736, installed in a printer comprising:
a printhead comprising at least a first elongate printhead module, the at least one printhead module including at least one row of print nozzles for expelling ink; and at least first and second printer controllers configured to receive print data and process the print data to output dot data to the printhead, wherein the first and second printer controllers are connected to a common input of the printhead.

751. A printer controller according to claim 736, installed in a printer comprising:
a printhead comprising first and second elongate printhead modules, the printhead modules being parallel to each other and being disposed end to end on either side of a join region;
at least first and second printer controllers configured to receive print data and process the print data to output dot data to the printhead, wherein the first printer controller outputs dot data only to the fust printhead module and the second printer controller outputs dot data only to the second printhead module, wherein the printhead modules are configured such that no dot data passes between them.

752. A printer controller according to claim 736, installed in a printer comprising:
a printhead comprising first and second elongate printhead modules, the printhead modules being parallel to each other and being disposed end to end on either side of a join region, wherein the first printhead module is longer than the second printhead module;
at least first and second printer controllers configured to receive print data and process the print data to output dot data to the printhead, wherein: the first printer controller outputs dot data to both the first printhead module and the second printhead module; and the second printer controller outputs dot data only to the second printhead module.

753. A printer controller according to claim 736, installed in a printer comprising:

a printhead comprising first and second elongate printhead modules, the printhead modules being parallel to each other and being disposed end to end on either side of a join region, wherein the first printhead module is longer than the second printhead module;
at least first and second printer controllers configured to receive print data and process the print data to output dot data for the printhead, wherein: the first printer controller outputs dot data to both the first printhead module and the second controller, and the second printer controller outputs dot data to the second printhead module, wherein the dot data output by the second printer controller includes dot data it generates and at least some of the dot data received from the first printer controller.

754. A printer controller according to claim 736, for supplying dot data to at least one printhead module and at least partially compensating for errors in ink dot placement by at least one of a plurality of nozzles on the printhead module due to erroneous rotational displacement of the printhead module relative to a carrier, the printer being configured to:
access a correction factor associated with the at least one printhead module;
determine an order in which at least some of the dot data is supplied to at least one of the at least one printhead modules, the order being determined at least partly on the basis of the correction factor, thereby to at least partially compensate for the rotational displacement; and supply the dot data to the printhead module.

755. A printer controller according to claim 736, for supplying dot data to a printhead module having a plurality of nozzles for expelling ink, the printhead module including a plurality of thermal sensors, each of the thermal sensors being configured to respond to a temperature at or adjacent at least one of the nozzles, the printer controller being configured to modify operation of at least some of the nozzles in response to the temperature rising above a first threshold.

756. A printer controller according to claim 736, for controlling a printhead comprising at least one monolithic printhead module, the at least one printhead module having a plurality of rows of nozzles configured to extend, in use, across at least part of a printable pagewidth of the printhead, the nozzles in each row being grouped into at least first and second fire groups, the printhead module being configured to sequentially fire, for each row, the nozzles of each fire group, such that each nozzle in the sequence from each fire group is fired simultaneously with respective corresponding nozzles in the sequence in the other fire groups, wherein the nozzles are fired row by row such that the nozzles of each row are all fired before the nozzles of each subsequent row, wherein the printer controller is configured to provide one or more control signals that control the order of firing of the nozzles.

757. A printer controller according to claim 736, for outputting to a printhead module:
dot data to be printed with at least two different inks; and control data for controlling printing of the dot data;
the printer controller including at least one communication output, each or the communication output being configured to output at least some of the control data and at least some of the dot data for the at least two inks.

758. A printer controller according to claim 736, for supplying data to a printhead module including at least one row of printhead nozzles, at least one row including at least one displaced row portion, the displacement of the row portion including a component in a direction normal to that of a pagewidth to be printed.

759. A printer controller according to claim 736, for supplying print data to at least one printhead module capable of printing a maximum of n of channels of print data, the at least one printhead module being configurable into:
a first mode, in which the printhead module is configured to receive data for a first number of the channels; and a second mode, in which the printhead module is configured to receive print data for a second number of the channels, wherein the first number is greater than the second number;
wherein the printer controller is selectively configurable to supply dot data for the first and second modes.

760. A printer controller according to claim 736, for supplying data to a printhead comprising a plurality of printhead modules, the printhead being wider than a reticle step used in forming the modules, the printhead comprising at least two types of the modules, wherein each type is determined by its geometric shape in plan.

761. A printer controller according to claim 736, for supplying one or more control signals to a printhead module, the printhead module including at least one row that comprises a plurality of adjacent sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, the method comprising providing, for each set of nozzles, a fire signal in accordance with the sequence: [nozzle position 1, nozzle position n, nozzle position 2, nozzle position (n-1), ... , nozzle position x], wherein nozzle position x is at or adjacent the centre of the set of nozzles.

762. A printer controller according to claim 736, for supplying dot data to a printhead module comprising at least first and second rows configured to print ink of a similar type or color, at least some nozzles in the first row being aligned with respective corresponding nozzles in the second row in a direction of intended media travel relative to the printhead, the printhead module being configurable such that the nozzles in the first and second pairs of rows are fired such that some dots output to print media are printed to by nozzles from the first pair of rows and at least some other dots output to print media are printed to by nozzles from the second pair of rows, the printer controller being configurable to supply dot data to the printhead module for printing.

763. A printer controller according to claim 736, for supplying dot data to at least one printhead module, the at least one printhead module comprising a plurality of rows, each of the rows comprising a plurality of nozzles for ejecting ink, wherein the printhead module includes at least first and second rows configured to print ink of a similar type or color, the printer controller being configured to supply the dot data to the at least one printhead module such that, in the event a nozzle in the first row is faulty, a corresponding nozzle in the second row prints an ink dot at a position on print media at or adjacent a position where the faulty nozzle would otherwise have printed it.

764. A printer controller according to claim 736, for receiving first data and manipulating the first data to produce dot data to be printed, the print controller including at least two serial outputs for supplying the dot data to at least one printhead.

765. A printer controller according to claim 736, for supplying data to a printhead module including:
at least one row of print nozzles;
at least first and second shift registers for shifting in dot data supplied from a data source, wherein each shift register feeds dot data to a group of nozzles, and wherein each of the groups of the nozzles is interleaved with at least one of the other groups of the nozzles.

766. A printer controller according to claim 736, for supplying data to a printhead capable of printing a maximum of n of channels of print data, the printhead being configurable into:
a first mode, in which the printhead is configured to receive print data for a first number of the channels; and a second mode, in which the printhead is configured to receive print data for a second number of the channels, wherein the first number is greater than the second number.

767. A printer controller according to claim 736, for supplying data to a printhead comprising a plurality of printhead modules, the printhead being wider than a reticle step used in forming the modules, the printhead comprising at least two types of the modules, wherein each type is determined by its geometric shape in plan.

768. A printer controller according to claim 736, for supplying data to a printhead module including at least one row that comprises a plurality of sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, such that, for each set of nozzles, a fire signal is provided in accordance with the sequence: [nozzle position 1, nozzle position n, nozzle position 2, nozzle position (n-1), ... , nozzle position x], wherein nozzle position x is at or adjacent the centre of the set of nozzles.

769. A printer controller according to claim 736, for supplying data to a printhead module including at least one row that comprises a plurality of adjacent sets of n adjacent nozzles, each of the nozzles being configured to expel the ink in response to a fire signal, the printhead being configured to output ink from nozzles at a first and nth position in each set of nozzles, and then each next inward pair of nozzles in each set, until:
in the event n is an even number, all of the nozzles in each set has been fired; and in the event n is an odd number, all of the nozzles but a central nozzle in each set have been fired, and then to fire the central nozzle.

770. A printer controller according to claim 736, for supplying data to a printhead module for receiving dot data to be printed using at least two different inks and control data for controlling printing of the dot data, the printhead module including a communication input for receiving the dot data for the at least two colors and the control data.

771. A printer controller according to claim 736, for supplying data to a printhead module including at least one row of printhead nozzles, at least one row including at least one displaced row portion, the displacement of the row portion including a component in a direction normal to that of a pagewidth to be printed.

772. A printer controller according to claim 736, for supplying data to a printhead module having a plurality of rows of nozzles configured to extend, in use, across at least part , of a printable pagewidth, the nozzles in each row being grouped into at least first and second fire groups, the printhead module being configured to sequentially fire, for each row, the nozzles of each fire group, such that each nozzle in the sequence from each fire group is fired simultaneously with respective corresponding nozzles in the sequence in the other fire groups, wherein the nozzles are fired row by row such that the nozzles of each row are all fired before the nozzles of each subsequent row.

773. A printer controller according to claim 736, for supplying data to a printhead module comprising at least first and second rows configured to print ink of a similar type or color, at least some nozzles in the first row being aligned with respective corresponding nozzles in the second row in a direction of intended media travel relative to the printhead, the printhead module being configurable such that the nozzles in the first and second pairs of rows are fired such that some dots output to print media are printed to by nozzles from the first pair of rows and at least some other dots output to print media are printed to by nozzles from the second pair of rows.

774. A printer controller according to claim 736, for providing data to a printhead module that includes:
at least one row of print nozzles;
at least first and second shift registers for shifting in dot data supplied from a data source, wherein each shift register feeds dot data to a group of nozzles, and wherein each of the groups of the nozzles is interleaved with at least one of the other groups of the nozzles.

775. A printer controller according to claim 736, for supplying data to a printhead module having a plurality of nozzles for expelling ink, the printhead module including a plurality of thermal sensors, each of the thermal sensors being configured to respond to a temperature at or adjacent at least one of the nozzles, the printhead module being configured to modify operation of the nozzles in response to the temperature rising above a first threshold.

776. A printer controller according to claim 736, for supplying data to a printhead module comprising a plurality of rows, each of the rows comprising a plurality of nozzles for ejecting ink, wherein the printhead module includes at least first and second rows configured to print ink of a similar type or color, and being configured such that, in the event a nozzle in the first row is faulty, a corresponding nozzle in the second row prints an ink dot at a position on print media at or adjacent a position where the faulty nozzle would otherwise have printed it.

777. A printer controller according to claim 736, wherein the printhead module includes a plurality of the rows, the printer controller being configured to cause firing of each nozzle in each row simultaneously with the nozzle or nozzles at the same position in the other rows.

778. A printer controller according to claim 736, including a plurality of pairs of the rows, each pair of rows including an odd row and an even row, the odd and even rows in each pair being offset from each other in both x and y directions relative to an intended direction of print media movement relative to the printhead, the printer controller being configured to control the at least one printhead module to cause firing of at least a plurality of the odd rows prior to firing any of the even rows, or vice versa.

779. A printer controller according to claim 778, wherein all the odd rows are fired before any of the even rows are fired, or vice versa.

780. A printer controller according to claim 778, configured to control the printhead such that the odd rows, or the even rows, or both, are fired in a predetermined order.

781. A printer controller according to claim 780, configurable such that the predetermined order is selectable from a plurality of predetermined available orders.

782. A printer controller according to claim 778, wherein the predetermined order is sequential.

783. A printer controller according to claim 782, configurable such that the predetermined order can commence at any of a plurality of the rows.

784. A printer controller for supplying one or more control signals to a printhead module, the printhead module including at least one row that comprises a plurality of adjacent sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, the method comprising providing, for each set of nozzles, a fire signal in accordance with the sequence: [nozzle position 1, nozzle position n, nozzle position 2, nozzle position (n-1), ... , nozzle position x], wherein nozzle position x is at or adjacent the centre of the set of nozzles.

785. A printer controller according to claim 784, configured to cause the nozzle at each given position within the set to be fired simultaneously with the nozzles in the other sets at respective corresponding positions.

786. A printer controller according to claim 784, wherein the printhead module includes a plurality of the rows of nozzles, the printer controller being configured to control the printhead module such that the steps are repeated for each of the rows of nozzles.

787. A printer controller according to claim 786, wherein the rows are disposed in pairs.

788. A printer controller according to claim 787, wherein the rows in each pair of rows are offset relative to each other.

789. A printer controller according to claim 788, wherein each pair of rows is configured to print the same color ink.

790. A printer controller according to claim 789, wherein each pair of rows is connected to a common ink source.

791. A printer controller according to claim 784, wherein the sets of nozzles are adjacent each other.

792. A printer controller according to claim 784, wherein the sets of nozzles are separated by an intermediate nozzle, the intermediate nozzle being fired either prior to the nozzle at position 1 in each set, or following the nozzle at position n.

793. A printer controller according to claim 784, wherein the printhead module is one of a plurality of printhead modules that form a pagewidth printhead, the printer controller being configure to supply the control signals to at least a plurality of the printhead modules.

794. A printer controller according to claim 784, for implementing a method of at least partially compensating for errors in ink dot placement by at least one of a plurality of nozzles due to erroneous rotational displacement of a printhead module relative to a carrier, the nozzles being disposed on the printhead module, the method comprising the steps of:
determining the rotational displacement;

determining at least one correction factor that at least partially compensates for the ink dot displacement; and using the correction factor to alter the output of the ink dots to at least partially compensate for the rotational displacement.

795. A printer controller according to claim 784 for implementing a method of expelling ink from a printhead module including at least one row that comprises a plurality of adjacent sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, the method comprising providing, for each set of nozzles, a fire signal in accordance with the sequence: [nozzle position 1, nozzle position n, nozzle position 2, nozzle position (n-1), ... , nozzle position x], wherein nozzle position x is at or adjacent the centre of the set of nozzles.

796. A printer controller according to claim 784, for implementing a method of expelling ink from a printhead module including at least one row that comprises a plurality of sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, the method comprising the steps of (a). providing a fire signal to nozzles at a first and nth position in each set of nozzles;
(b). providing a fire signal to the next inward pair of nozzles in each set;
(c). in the event n is an even number, repeating step (b) until all of the nozzles in each set has been fired; and (d). in the event n is an odd number, repeating step (b) until all of the nozzles but a central nozzle in each set have been fired, and then firing the central nozzle.

797. A printer controller according to claim 784, manufactured in accordance with a method of manufacturing a plurality of printhead modules, at least some of which are capable of being combined in pairs to form bilithic pagewidth printheads, the method comprising the step of laying out each of the plurality of printhead modules on a wafer substrate, wherein at least one of the printhead modules is right-handed and at least another is left-handed.

798. A printer controller according to claim 784, for supplying data to a printhead module including:
at least one row of print nozzles;
at least two shift registers for shifting in dot data supplied from a data source to each of the at least one rows, wherein each print nozzle obtains dot data to be fired from an element of one of the shift registers.

799. A printer controller according to claim 784, installed in a printer comprising:
a printhead comprising at least a first elongate printhead module, the at least one printhead module including at least one row of print nozzles for expelling ink; and at least first and second printer controllers configured to receive print data and process the print data to output dot data to the printhead, wherein the first and second printer controllers are connected to a common input of the printhead.

800. A printer controller according to claim 784, installed in a printer comprising:
a printhead comprising first and second elongate printhead modules, the printhead modules being parallel to each other and being disposed end to end on either side of a join region;
at least first and second printer controllers configured to receive print data and process the print data to output dot data to the printhead, wherein the first printer controller outputs dot data only to the first printhead module and the second printer controller outputs dot data only to the second printhead module, wherein the printhead modules are configured such that no dot data passes between them.

801. A printer controller according to claim 784, installed in a printer comprising:
a printhead comprising first and second elongate printhead modules, the printhead modules being parallel to each other and being disposed end to end on either side of a join region, wherein the first printhead module is longer than the second printhead module;
at least first and second printer controllers configured to receive print data and process the print data to output dot data to the printhead, wherein: the first printer controller outputs dot data to both the first printhead module and the second printhead module; and the second printer controller outputs dot data only to the second printhead module.

802. A printer controller according to claim 784, installed in a printer comprising:
a printhead comprising first and second elongate printhead modules, the printhead modules being parallel to each other and being disposed end to end on either side of a join region, wherein the first printhead module is longer than the second printhead module;
at least first and second printer controllers configured to receive print data and process the print data to output dot data for the printhead, wherein: the first printer controller outputs dot data to both the first printhead module and the second controller, and the second printer controller outputs dot data to the second printhead module, wherein the dot data output by the second printer controller includes dot data it generates and at least some of the dot data received from the first printer controller.

803. A printer controller according to claim 784, for supplying dot data to at least one printhead module and at least partially compensating for errors in ink dot placement by at least one of a plurality of nozzles on the printhead module due to erroneous rotational displacement of the printhead module relative to a carrier, the printer being configured to:
access a correction factor associated with the at least one printhead module;
determine an order in which at least some of the dot data is supplied to at least one of the at least one printhead modules, the order being determined at least partly on the basis of the correction factor, thereby to at least partially compensate for the rotational displacement; and supply the dot data to the printhead module.

804. A printer controller according to claim 784, for supplying dot data to a printhead module having a plurality of nozzles for expelling ink, the printhead module including a plurality of thermal sensors, each of the thermal sensors being configured to respond to a temperature at or adjacent at least one of the nozzles, the printer controller being configured to modify operation of at least some of the nozzles in response to the temperature rising above a first threshold.

805. A printer controller according to claim 784, for controlling a printhead comprising at least one monolithic printhead module, the at least one printhead module having a plurality of rows of nozzles configured to extend, in use, across at least part of a printable pagewidth of the printhead, the nozzles in each row being grouped into at least first and second fire groups, the printhead module being configured to sequentially fire, for each row, the nozzles of each fire group, such that each nozzle in the sequence from each fire group is fired simultaneously with respective corresponding nozzles in the sequence in the other fire groups, wherein the nozzles are fired row by row such that the nozzles of each row are all fired before the nozzles of each subsequent row, wherein the printer controller is configured to provide one or more control signals that control the order of firing of the nozzles.

806. A printer controller according to claim 784, for outputting to a printhead module:
dot data to be printed with at least two different inks; and control data for controlling printing of the dot data;
the printer controller including at least one communication output, each or the communication output being configured to output at least some of the control data and at least some of the dot data for the at least two inks.

807. A printer controller according to claim 784, for supplying data to a printhead module including at least one row of printhead nozzles, at least one row including at least one displaced row portion, the displacement of the row portion including a component in a direction normal to that of a pagewidth to be printed.

808. A printer controller according to claim 784, for supplying print data to at least one printhead module capable of printing a maximum of n of channels of print data, the at least one printhead module being configurable into:
a first mode, in which the printhead module is configured to receive data for a first number of the channels; and a second mode, in which the printhead module is configured to receive print data for a second number of the channels, wherein the first number is greater than the second number;
wherein the printer controller is selectively configurable to supply dot data for the first and second modes.

809. A printer controller according to claim 784, for supplying data to a printhead comprising a plurality of printhead modules, the printhead being wider than a reticle step used in forming the modules, the printhead comprising at least two types of the modules, wherein each type is determined by its geometric shape m plan.

810. A printer controller according to claim 784, for supplying one or more control signals to a printhead module, the printhead module including at least one row that comprises a plurality of sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, such that:
(a). a fire signal is provided to nozzles at a first and nth position in each set of nozzles;
(b). a fire signal is provided to the next inward pair of nozzles in each set;
(c). in the event n is an even number, step (b) is repeated until all of the nozzles in each set has been fired;
and (d). in the event n is an odd number, step (b) is repeated until all of the nozzles but a central nozzle in each set have been fired, and then the central nozzle is fired.

811. A printer controller according to claim 784, for supplying dot data to a printhead module comprising at least first and second rows configured to print ink of a similar type or color, at least some nozzles in the first row being aligned with respective corresponding nozzles in the second row in a direction of intended media travel relative to the printhead, the printhead module being configurable such that the nozzles in the first and second pairs of rows are fired such that some dots output to print media are printed to by nozzles from the first pair of rows and at least some other dots output to print media are printed to by nozzles from the second pair of rows, the printer controller being configurable to supply dot data to the printhead module for printing.

812. A printer controller according to claim 784, for supplying dot data to at least one printhead module, the at least one printhead module comprising a plurality of rows, each of the rows comprising a plurality of nozzles for ejecting ink, wherein the printhead module includes at least first and second rows configured to print ink of a similar type or color, the printer controller being configured to supply the dot data to the at least one printhead module such that, in the event a nozzle in the first row is faulty, a corresponding nozzle in the second row prints an ink dot at a position on print media at or adjacent a position where the faulty nozzle would otherwise have printed it.

813. A printer controller according to claim 784, for receiving first data and manipulating the first data to produce dot data to be printed, the print controller including at least two serial outputs for supplying the dot data to at least one printhead.

814. A printer controller according to claim 784, for supplying data to a printhead module including:
at least one row of print nozzles;
at least first and second shift registers for shifting in dot data supplied from a data source, wherein each shift register feeds dot data to a group of nozzles, and wherein each of the groups of the nozzles is interleaved with at least one of the other groups of the nozzles.

815. A printer controller according to claim 784, for supplying data to a printhead capable of printing a maximum of n of channels of print data, the printhead being configurable into:
a first mode, in which the printhead is configured to receive print data for a first number of the channels; and a second mode, in which the printhead is configured to receive print data for a second number of the channels, wherein the first number is greater than the second number.

816. A printer controller according to claim 784, for supplying data to a printhead comprising a plurality of printhead modules, the printhead being wider than a reticle step used in forming the modules, the printhead comprising at least two types of the modules, wherein each type is determined by its geometric shape in plan.

817. A printer controller according to claim 784, for supplying data to a printhead module including at least one row that comprises a plurality of sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, such that, for each set of nozzles, a fire signal is provided in accordance with the sequence: [nozzle position 1, nozzle position n, nozzle position 2, nozzle position (n-1), ... , nozzle position x], wherein nozzle position x is at or adjacent the centre of the set of nozzles.

818. A printer controller according to claim 784, for supplying data to a printhead module including at least one row that comprises a plurality of adjacent sets of n adjacent nozzles, each of the nozzles being configured to expel the ink in response to a fire signal, the printhead being configured to output ink from nozzles at a first and nth position in each set of nozzles, and then each next inward pair of nozzles in each set, until:
in the event n is an even number, all of the nozzles in each set has been fired; and in the event n is an odd number, all of the nozzles but a central nozzle in each set have been fired, and then to fire the central nozzle.

819. A printer controller according to claim 784, for supplying data to a printhead module for receiving dot data to be printed using at least two different inks and control data for controlling printing of the dot data, the printhead module including a communication input for receiving the dot data for the at least two colors and the control data.

820. A printer controller according to claim 784, for supplying data to a printhead module including at least one row of printhead nozzles, at least one row including at least one displaced row portion, the displacement of the row portion including a component in a direction normal to that of a pagewidth to be printed.

821. A printer controller according to claim 784, for supplying data to a printhead module having a plurality of rows of nozzles configured to extend, in use, across at least part of a printable pagewidth, the nozzles in each row being grouped into at least first and second fire groups, the printhead module being configured to sequentially fire, for each row, the nozzles of each fire group, such that each nozzle in the sequence from each fire group is fired simultaneously with respective corresponding nozzles in the sequence in the other fire groups, wherein the nozzles are fired row by row such that the nozzles of each row are all fired before the nozzles of each subsequent row.

822. A printer controller according to claim 784, for supplying data to a printhead module comprising at least first and second rows configured to print ink of a similar type or color, at least some nozzles in the first row being aligned with respective corresponding nozzles in the second row in a direction of intended media travel relative to the printhead, the printhead module being configurable such that the nozzles in the first and second pairs of rows are fired such that some dots output to print media are printed to by nozzles from the first pair of rows and at least some other dots output to print media are printed to by nozzles from the second pair of rows.

823. A printer controller according to claim 784, for providing data to a printhead module that includes:
at least one row of print nozzles;
at least first and second shift registers for shifting in dot data supplied from a data source, wherein each shift register feeds dot data to a group of nozzles, and wherein each of the groups of the nozzles is interleaved with at least one of the other groups of the nozzles.

824. A printer controller according to claim 784, for supplying data to a printhead module having a plurality of nozzles for expelling ink, the printhead module including a plurality of thermal sensors, each of the thermal sensors being configured to respond to a temperature at or adjacent at least one of the nozzles, the printhead module being configured to modify operation of the nozzles in response to the temperature rising above a first threshold.

825. A printer controller according to claim 784, for supplying data to a printhead module comprising a plurality of rows, each of the rows comprising a plurality of nozzles for ejecting ink, wherein the printhead module includes at least first and second rows configured to print ink of a similar type or color, and being configured such that, in the event a nozzle in the first row is faulty, a corresponding nozzle in the second row prints an ink dot at a position on print media at or adjacent a position where the faulty nozzle would otherwise have printed it.

826. A printer controller according to claim 784, wherein the printhead module includes a plurality of the rows, the printer controller being configured to cause firing of each nozzle in each row simultaneously with the nozzle or nozzles at the same position in the other rows.

827. A printer controller according to claim 784, including a plurality of pairs of the rows, each pair of rows including an odd row and an even row, the odd and even rows in each pair being offset from each other in both x and y directions relative to an intended direction of print media movement relative to the printhead, the printer controller being configured to control the at least one printhead module to cause firing of at least a plurality of the odd rows prior to firing any of the even rows, or vice versa.

828. A printer controller according to claim 827 wherein all the odd rows are fired before any of the even rows are fired, or vice versa.

829. A printer controller according to claim 827 configured to control the printhead such that the odd rows, or the even rows, or both, are fired in a predetermined order.

830. A printer controller according to claim 829, configurable such that the predetermined order is selectable from a plurality of predetermined available orders.

831. A printer controller according to claim 827 wherein the predetermined order is sequential.

832. A printer controller according to claim 831, configurable such that the predetermined order can commence at any of a plurality of the rows.

833. A printer controller for supplying dot data to a printhead module comprising at least first and second rows configured to print ink of a similar type or color, at least some nozzles in the first row being aligned with respective corresponding nozzles in the second row in a direction of intended media travel relative to the printhead, the printhead module being configurable such that the nozzles in the first and second pairs of rows are fired such that some dots output to print media are printed to by nozzles from the first pair of rows and at least some other dots output to print media are printed to by nozzles from the second pair of rows, the printer controller being configurable to supply dot data to the printhead module for printing.

834. A print engine comprising a printer controller according to claim 833 and the printhead module, wherein the printhead module is controllable such that either of the nozzles in each aligned pair of nozzles in the first and second rows can be selected to output ink for a selected dot to be printed on the print media.

835. A print engine according to claim 834, wherein, in the event a nozzle in the first row is faulty, the corresponding nozzle in the second row is selected to output ink for a dot for which the faulty nozzle would otherwise have output ink.

836. A print engine according to claim 834, including a plurality of sets of the first and second rows.

837. A print engine according to claim 836, wherein each of the sets of the first and second rows is configured to print in a single color or ink type.

838. A print engine according to claim 837, wherein the fust and second rows in at least one of the sets are separated by one or more rows from the other set or sets.

839. A print engine according to claim 833, wherein each of the rows includes an odd sub-row and an even sub-row, the odd and even sub-rows being offset with respect to each other in a direction of intended print media travel relative to the printhead.

840. A print engine according to claim 839, wherein the odd and even sub-rows are transversely offset relative to each other.

841. A print engine according to claim 834, configured such that the first and second rows are fired alternately.

842. A print engine according to claim 834, comprising a plurality of the printhead modules.

843. A printer including a printer controller according to claim 833.

844. A printer including a print engine according to claim 834.

845. A printer controller according to claim 833, for implementing a method of at least partially compensating for errors in ink dot placement by at least one of a plurality of nozzles due to erroneous rotational displacement of a printhead module relative to a carrier, the nozzles being disposed on the printhead module, the method comprising the steps of:
determining the rotational displacement;
determining at least one correction factor that at least partially compensates for the ink dot displacement; and using the correction factor to alter the output of the ink dots to at least partially compensate for the rotational displacement.

846. A printer controller according to claim 833 for implementing a method of expelling ink from a printhead module including at least one row that comprises a plurality of adjacent sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, the method comprising providing, for each set of nozzles, a fire signal in accordance with the sequence: [nozzle position 1, nozzle position n, nozzle position 2, nozzle position (n-1), ... , nozzle position x], wherein nozzle position x is at or adjacent the centre of the set of nozzles.

847. A printer controller according to claim 833, for implementing a method of expelling ink from a printhead module including at least one row that comprises a plurality of sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, the method comprising the steps of:
(a). providing a fire signal to nozzles at a first and nth position in each set of nozzles;
(b). providing a fire signal to the next inward pair of nozzles in each set;
(c). in the event n is an even number, repeating step (b) until all of the nozzles in each set has been fired; and (d). in the event n is an odd number, repeating step (b) until all of the nozzles but a central nozzle in each set have been fired, and then firing the central nozzle.

848. A printer controller according to claim 833, manufactured in accordance with a method of manufacturing a plurality of printhead modules, at least some of which are capable of being combined in pairs to form bilithic pagewidth printheads, the method comprising the step of laying out each of the plurality of printhead modules on a wafer substrate, wherein at least one of the printhead modules is right-handed and at least another is left-handed.

849. A printer controller according to claim 833, for supplying data to a printhead module including:
at least one row of print nozzles;
at least two shift registers for shifting in dot data supplied from a data source to each of the at least one rows, wherein each print nozzle obtains dot data to be fired from an element of one of the shift registers.

850. A printer controller according to claim 833, installed in a printer comprising:
a printhead comprising at least a first elongate printhead module, the at least one printhead module including at least one row of print nozzles for expelling ink; and at least first and second printer controllers configured to receive print data and process the print data to output dot data to the printhead, wherein the first and second printer controllers are connected to a common input of the printhead.

851. A printer controller according to claim 833, installed in a printer comprising:
a printhead comprising first and second elongate printhead modules, the printhead modules being parallel to each other and being disposed end to end on either side of a join region;
at least first and second printer controllers configured to receive print data and process the print data to output dot data to the printhead, wherein the first printer controller outputs dot data only to the first printhead module and the second printer controller outputs dot data only to the second printhead module, wherein the printhead modules are configured such that no dot data passes between them.

852. A printer controller according to claim 833, installed in a printer comprising:

a printhead comprising first and second elongate printhead modules, the printhead modules being parallel to each other and being disposed end to end on either side of a join region, wherein the first printhead module is longer than the second printhead module;
at least first and second printer controllers configured to receive print data and process the print data to output dot data to the printhead, wherein: the first printer controller outputs dot data to both the first printhead module and the second printhead module; and the second printer controller outputs dot data only to the second printhead module.

853. A printer controller according to claim 833, installed in a printer comprising:
a printhead comprising first and second elongate printhead modules, the printhead modules being parallel to each other and being disposed end to end on either side of a join region, wherein the fust printhead module is longer than the second printhead module;
at least first and second printer controllers configured to receive print data and process the print data to output dot data for the printhead, wherein: the first printer controller outputs dot data to both the first printhead module and the second controller; and the second printer controller outputs dot data to the second printhead module, wherein the dot data output by the second printer controller includes dot data it generates and at least some of the dot data received from the first printer controller.

854. A printer controller according to claim 833, for supplying dot data to at least one printhead module and at least partially compensating for errors in ink dot placement by at least one of a plurality of nozzles on the printhead module due to erroneous rotational displacement of the printhead module relative to a carrier, the printer being configured to:
access a correction factor associated with the at least one printhead module;
determine an order in which at least some of the dot data is supplied to at least one of the at least one printhead modules, the order being determined at least partly on the basis of the correction factor, thereby to at least partially compensate for the rotational displacement; and supply the dot data to the printhead module.

855. A printer controller according to claim 833, for supplying dot data to a printhead module having a plurality of nozzles for expelling ink, the printhead module including a plurality of thermal sensors, each of the thermal sensors being configured to respond to a temperature at or adjacent at least one of the nozzles, the printer controller being configured to modify operation of at least some of the nozzles in response to the temperature rising above a first threshold.

856. A printer controller according to claim 833, for controlling a printhead comprising at least one monolithic printhead module, the at least one printhead module having a plurality of rows of nozzles configured to extend, in use, across at least part of a printable pagewidth of the printhead, the nozzles in each row being grouped into at least first and second fire groups, the printhead module being configured to sequentially fire, for each row, the nozzles of each fire group, such that each nozzle in the sequence from each fire group is fired simultaneously with respective corresponding nozzles in the sequence in the other fire groups, wherein the nozzles are fired row by row such that the nozzles of each row are all fired before the nozzles of each subsequent row, wherein the printer controller is configured to provide one or more control signals that control the order of firing of the nozzles.

857. A printer controller according to claim 833, for outputting to a printhead module:
dot data to be printed with at least two different inks; and control data for controlling printing of the dot data;
the printer controller including at least one communication output, each or the communication output being configured to output at least some of the control data and at least some of the dot data for the at least two inks.

858. A printer controller according to claim 833, for supplying data to a printhead module including at least one row of printhead nozzles, at least one row including at least one displaced row portion, the displacement of the row portion including a component in a direction normal to that of a pagewidth to be printed.

859. A printer controller according to claim 833, for supplying print data to at least one printhead module capable of printing a maximum of n of channels of print data, the at least one printhead module being configurable into:
a first mode, in which the printhead module is configured to receive data for a first number of the channels; and a second mode, in which the printhead module is configured to receive print data for a second number of the channels, wherein the first number is greater than the second number, wherein the printer controller is selectively configurable to supply dot data for the first and second modes.

860. A printer controller according to claim 833, for supplying data to a printhead comprising a plurality of printhead modules, the printhead being wider than a reticle step used in forming the modules, the printhead comprising at least two types of the modules, wherein each type is determined by its geometric shape in plan.

861. A printer controller according to claim 833, for supplying one or more control signals to a printhead module, the printhead module including at least one row that comprises a plurality of sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, such that:
a fire signal is provided to nozzles at a first and nth position in each set of nozzles;
a fire signal is provided to the next inward pair of nozzles in each set;
in the event n is an even number, step (b) is repeated until all of the nozzles in each set has been fired; and in the event n is an odd number, step (b) is repeated until all of the nozzles but a central nozzle in each set have been fired, and then the central nozzle is fired.

862. A printer controller according to claim 833, for supplying one or more control signals to a printhead module, the printhead module including at least one row that comprises a plurality of adjacent sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, the method comprising providing, for each set of nozzles, a fire signal in accordance with the sequence: [nozzle position 1, nozzle position n, nozzle position 2, nozzle position (n-1), ... , nozzle position x], wherein nozzle position x is at or adjacent the centre of the set of nozzles.

863. A printer controller according to claim 833, for supplying dot data to at least one printhead module, the at least one printhead module comprising a plurality of rows, each of the rows comprising a plurality of nozzles for ejecting ink, wherein the printhead module includes at least first and second rows configured to print ink of a similar type or color, the printer controller being configured to supply the dot data to the at least one printhead module such that, in the event a nozzle in the first row is faulty, a corresponding nozzle in the second row prints an ink dot at a position on print media at or adjacent a position where the faulty nozzle would otherwise have printed it.

864. A printer controller according to claim 833, for receiving first data and manipulating the first data to produce dot data to be printed, the print controller including at least two serial outputs for supplying the dot data to at least one printhead.

865. A printer controller according to claim 833, for supplying data to a printhead module including:
at least one row of print nozzles;
at least first and second shift registers for shifting in dot data supplied from a data source, wherein each shift register feeds dot data to a group of nozzles, and wherein each of the groups of the nozzles is interleaved with at least one of the other groups of the nozzles.

866. A printer controller according to claim 833, for supplying data to a printhead capable of printing a maximum of n of channels of print data, the printhead being configurable into:
a first mode, in which the printhead is configured to receive print data for a first number of the channels; and a second mode, in which the printhead is configured to receive print data for a second number of the channels, wherein the first number is greater than the second number.

867. A printer controller according to claim 833, for supplying data to a printhead comprising a plurality of printhead modules, the printhead being wider than a reticle step used in forming the modules, the printhead comprising at least two types of the modules, wherein each type is determined by its geometric shape in plan.

868. A printer controller according to claim 833, for supplying data to a printhead module including at least one row that comprises a plurality of sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, such that, for each set of nozzles, a fire signal is provided in accordance with the sequence: [nozzle position 1, nozzle position n, nozzle position 2, nozzle position (n-1), ... , nozzle position x], wherein nozzle position x is at or adjacent the centre of the set of nozzles.

869. A printer controller according to claim 833, for supplying data to a printhead module including at least one row that comprises a plurality of adjacent sets of n adjacent nozzles, each of the nozzles being configured to expel the ink in response to a fire signal, the printhead being configured to output ink from nozzles at a first and nth position in each set of nozzles, and then each next inward pair of nozzles in each set, until:
in the event n is an even number, all of the nozzles in each set has been fired; and in the event n is an odd number, all of the nozzles but a central nozzle in each set have been fired, and then to fire the central nozzle.

870. A printer controller according to claim 833, for supplying data to a printhead module for receiving dot data to be printed using at least two different inks and control data for controlling printing of the dot data, the printhead module including a communication input for receiving the dot data for the at least two colors and the control data.

871. A printer controller according to claim 833, for supplying data to a printhead module including at least one row of printhead nozzles, at least one row including at least one displaced row portion, the displacement of the row portion including a component in a direction normal to that of a pagewidth to be printed.

872. A printer controller according to claim 833, for supplying data to a printhead module having a plurality of rows of nozzles configured to extend, in use, across at least part of a printable pagewidth, the nozzles in each row being grouped into at least first and second fire groups, the printhead module being configured to sequentially fire, for each row, the nozzles of each fire group, such that each nozzle in the sequence from each fire group is fired simultaneously with respective corresponding nozzles in the sequence in the other fire groups, wherein the nozzles are fired row by row such that the nozzles of each row are all fired before the nozzles of each subsequent row.

873. A printer controller according to claim 833, for supplying data to a printhead module comprising at least first and second rows configured to print ink of a similar type or color, at least some nozzles in the first row being aligned with respective corresponding nozzles in the second row in a direction of intended media travel relative to the printhead, the printhead module being configurable such that the nozzles in the first and second pairs of rows are fired such that some dots output to print media are printed to by nozzles from the first pair of rows and at least some other dots output to print media are printed to by nozzles from the second pair of rows.

874. A printer controller according to claim 833, for providing data to a printhead module that includes:
at least one row of print nozzles;
at least fust and second shift registers for shifting in dot data supplied from a data source, wherein each shift register feeds dot data to a group of nozzles, and wherein each of the groups of the nozzles is interleaved with at least one of the other groups of the nozzles.

875. A printer controller according to claim 833, for supplying data to a printhead module having a plurality of nozzles for expelling ink, the printhead module including a plurality of thermal sensors, each of the thermal sensors being configured to respond to a temperature at or adjacent at least one of the nozzles, the printhead module being configured to modify operation of the nozzles in response to the temperature rising above a first threshold.

876. A printer controller according to claim 833, for supplying data to a printhead module comprising a plurality of rows, each of the rows comprising a plurality of nozzles for ejecting ink, wherein the printhead module includes at least first and second rows configured to print ink of a similar type or color, and being configured such that, in the event a nozzle in the first row is faulty, a corresponding nozzle in the second row prints an ink dot at a position on print media at or adjacent a position where the faulty nozzle would otherwise have printed it.

877. A printer controller for supplying dot data to at least one printhead module, the at least one printhead module comprising a plurality of rows, each of the rows comprising a plurality of nozzles for ejecting ink, wherein the printhead module includes at least first and second rows configured to print ink of a similar type or color, the printer controller being configured to supply the dot data to the at least one printhead module such that, in the event a nozzle in the first row is faulty, a corresponding nozzle in the second row prints an ink dot at a position on print media at or adjacent a position where the faulty nozzle would otherwise have printed it.

878. A print engine comprising a printer controller according to claim 877 and the at least one printhead module, wherein each nozzle in the first row is paired with a nozzle in the second row, such that each pair of nozzles is aligned in an intended direction of print media travel relative to the printhead module.

879. A print engine according to claim 878, including a plurality of sets of the first and second rows.

880. A print engine according to claim 879, wherein each of the sets of the first and second rows is configured to print in a single color or ink type.

881. A print engine according to claim 877, wherein each of the rows includes an odd and an even sub-row, the odd and even sub-rows being offset with respect to each other in a direction of print media travel relative to the printhead in use.

882. A print engine according to claim 881, wherein the odd and even sub-rows are transversely offset with respect to each other.

883. A printer including at least one printer controller according to claim 877.

884. A printer including at least one print engine according to claim 878.

885. A printer controller according to claim 877, for implementing a method of at least partially compensating for errors in ink dot placement by at least one of a plurality of nozzles due to erroneous rotational displacement of a printhead module relative to a carrier, the nozzles being disposed on the printhead module, the method comprising the steps of:
determining the rotational displacement;
determining at least one correction factor that at least partially compensates for the ink dot displacement; and using the correction factor to alter the output of the ink dots to at least partially compensate for the rotational displacement.

886. A printer controller according to claim 877 for implementing a method of expelling ink from a printhead module including at least one row that comprises a plurality of adjacent sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, the method comprising providing, for each set of nozzles, a fire signal in accordance with the sequence: [nozzle position 1, nozzle position n, nozzle position 2, nozzle position (n-1), ... , nozzle position x], wherein nozzle position x is at or adjacent the centre of the set of nozzles.

887. A printer controller according to claim 877, for implementing a method of expelling ink from a printhead module including at least one row that comprises a plurality of sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, the method comprising the steps of:
(a). providing a fire signal to nozzles at a first and nth position in each set of nozzles;
(b). providing a fire signal to the next inward pair of nozzles in each set;
(c). in the event n is an even number, repeating step (b) until all of the nozzles in each set has been fired; and (d). in the event n is an odd number, repeating step (b) until all of the nozzles but a central nozzle in each set have been fired, and then firing the central nozzle.

888. A printer controller according to claim 877, manufactured in accordance with a method of manufacturing a plurality of printhead modules, at least some of which are capable of being combined in pairs to form bilithic pagewidth printheads, the method comprising the step of laying out each of the plurality of printhead modules on a wafer substrate, wherein at least one of the printhead modules is right-handed and at least another is left-handed.

889. A printer controller according to claim 877, for supplying data to a printhead module including:
at least one row of print nozzles;
at least two shift registers for shifting in dot data supplied from a data source to each of the at least one rows, wherein each print nozzle obtains dot data to be fired from an element of one of the shift registers.

890. A printer controller according to claim 877, installed in a printer comprising:
a printhead comprising at least a first elongate printhead module, the at least one printhead module including at least one row of print nozzles for expelling ink; and at least first and second printer controllers configured to receive print data and process the print data to output dot data to the printhead, wherein the first and second printer controllers are connected to a common input of the printhead.

891. A printer controller according to claim 877, installed in a printer comprising:
a printhead comprising first and second elongate printhead modules, the printhead modules being parallel to each other and being disposed end to end on either side of a join region;
at least first and second printer controllers configured to receive print data and process the print data to output dot data to the printhead, wherein the first printer controller outputs dot data only to the first printhead module and the second printer controller outputs dot data only to the second printhead module, wherein the printhead modules are configured such that no dot data passes between them.

892. A printer controller according to claim 877, installed in a printer comprising:
a printhead comprising first and second elongate printhead modules, the printhead modules being parallel to each other and being disposed end to end on either side of a join region, wherein the first printhead module is longer than the second printhead module;
at least first and second printer controllers configured to receive print data and process the print data to output dot data to the printhead, wherein: the first printer controller outputs dot data to both the first printhead module and the second printhead module; and the second printer controller outputs dot data only to the second printhead module.

893. A printer controller according to claim 877, installed in a printer comprising:

a printhead comprising first and second elongate printhead modules, the printhead modules being parallel to each other and being disposed end to end on either side of a join region, wherein the first printhead module is longer than the second printhead module;
at least first and second printer controllers configured to receive print data and process the print data to output dot data for the printhead, wherein: the first printer controller outputs dot data to both the first printhead module and the second controller, and the second printer controller outputs dot data to the second printhead module, wherein the dot data output by the second printer controller includes dot data it generates and at least some of the dot data received from the first printer controller.

894. A printer controller according to claim 877, for supplying dot data to at least one printhead module and at least partially compensating for errors in ink dot placement by at least one of a plurality of nozzles on the printhead module due to erroneous rotational displacement of the printhead module relative to a carrier, the printer being configured to:
access a correction factor associated with the at least one printhead module;
determine an order in which at least some of the dot data is supplied to at least one of the at least one printhead modules, the order being determined at least partly on the basis of the correction factor, thereby to at least partially compensate for the rotational displacement; and supply the dot data to the printhead module.

895. A printer controller according to claim 877, for supplying dot data to a printhead module having a plurality of nozzles for expelling ink, the printhead module including a plurality of thermal sensors, each of the thermal sensors being configured to respond to a temperature at or adjacent at least one of the nozzles, the printer controller being configured to modify operation of at least some of the nozzles in response to the temperature rising above a first threshold.

896. A printer controller according to claim 877, for controlling a printhead comprising at least one monolithic printhead module, the at least one printhead module having a plurality of rows of nozzles configured to extend, in use, across at least part of a printable pagewidth of the printhead, the nozzles in each row being grouped into at least fust and second fire groups, the printhead module being configured to sequentially fire, for each row, the nozzles of each fire group, such that each nozzle in the sequence from each fire group is fired simultaneously with respective corresponding nozzles in the sequence in the other fire groups, wherein the nozzles are fired row by row such that the nozzles of each row are all fired before the nozzles of each subsequent row, wherein the printer controller is configured to provide one or more control signals that control the order of firing of the nozzles.

897. A printer controller according to claim 877, for outputting to a printhead module:
dot data to be printed with at least two different inks; and control data for controlling printing of the dot data;
the printer controller including at least one communication output, each or the communication output being configured to output at least some of the control data and at least some of the dot data for the at least two inks.

898. A printer controller according to claim 877, for supplying data to a printhead module including at least one row of printhead nozzles, at least one row including at least one displaced row portion, the displacement of the row portion including a component in a direction normal to that of a pagewidth to be printed.

899. A printer controller according to claim 877, for supplying print data to at least one printhead module capable of printing a maximum of n of channels of print data, the at least one printhead module being configurable into:
a first mode, in which the printhead module is configured to receive data for a first number of the channels; and a second mode, in which the printhead module is configured to receive print data for a second number of the channels, wherein the first number is greater than the second number, wherein the printer controller is selectively configurable to supply dot data for the first and second modes.

900. A printer controller according to claim 877, for supplying data to a printhead comprising a plurality of printhead modules, the printhead being wider than a reticle step used in forming the modules, the printhead comprising at least two types of the modules, wherein each type is determined by its geometric shape in plan.

901. A printer controller according to claim 877, for supplying one or more control signals to a printhead module, the printhead module including at least one row that comprises a plurality of sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, such that:
(a). a fire signal is provided to nozzles at a first and nth position in each set of nozzles;
(b). a fire signal is provided to the next inward pair of nozzles in each set;
(c). in the event n is an even number, step (b) is repeated until all of the nozzles in each set has been fired;
and (d). in the event n is an odd number, step (b) is repeated until all of the nozzles but a central nozzle in each set have been fired, and then the central nozzle is fired.

902. A printer controller according to claim 877, for supplying one or more control signals to a printhead module, the printhead module including at least one row that comprises a plurality of adjacent sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, the method comprising providing, for each set of nozzles, a fire signal in accordance with the sequence: [nozzle position 1, nozzle position n, nozzle position 2, nozzle position (n-1), ... , nozzle position x], wherein nozzle position x is at or adjacent the centre of the set of nozzles.

903. A printer controller according to claim 877, for supplying dot data to a printhead module comprising at least first and second rows configured to print ink of a similar type or color, at least some nozzles in the first row being aligned with respective corresponding nozzles in the second row in a direction of intended media travel relative to the printhead, the printhead module being configurable such that the nozzles in the first and second pairs of rows are fired such that some dots output to print media are printed to by nozzles from the first pair of rows and at least some other dots output to print media are printed to by nozzles from the second pair of rows, the printer controller being configurable to supply dot data to the printhead module for printing.

904. A printer controller according to claim 877, for receiving first data and manipulating the fust data to produce dot data to be printed, the print controller including at least two serial outputs for supplying the dot data to at least one printhead.

905. A printer controller according to claim 877, for supplying data to a printhead module including:
at least one row of print nozzles;
at least first and second shift registers for shifting in dot data supplied from a data source, wherein each shift register feeds dot data to a group of nozzles, and wherein each of the groups of the nozzles is interleaved with at least one of the other groups of the nozzles.

906. A printer controller according to claim 877, for supplying data to a printhead capable of printing a maximum of n of channels of print data, the printhead being configurable into:
a first mode, in which the printhead is configured to receive print data, for a first number of the channels; and a second mode, in which the printhead is configured to receive print data for a second number of the channels, wherein the first number is greater than the second number.

907. A printer controller according to claim 877, for supplying data to a printhead comprising a plurality of printhead modules, the printhead being wider than a reticle step used m forming the modules, the printhead comprising at least two types of the modules, wherein each type is determined by its geometric shape in plan.

908. A printer controller according to claim 877, for supplying data to a printhead module including at least one row that comprises a plurality of sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, such that, for each set of nozzles, a fire signal is provided in accordance with the sequence: [nozzle position 1, nozzle position n, nozzle position 2, nozzle position (n-1), ... , nozzle position x], wherein nozzle position x is at or adjacent the centre of the set of nozzles.

909. A printer controller according to claim 877, for supplying data to a printhead module including at least one row that comprises a plurality of adjacent sets of n adjacent nozzles, each of the nozzles being configured to expel the ink in response to a fire signal, the printhead being configured to output ink from nozzles at a first and nth position in each set of nozzles, and then each next inward pair of nozzles in each set, until:
in the event n is an even number, all of the nozzles in each set has been fired; and in the event n is an odd number, all of the nozzles but a central nozzle in each set have been fired, and then to fire the central nozzle.

910. A printer controller according to claim 877, for supplying data to a printhead module for receiving dot data to be printed using at least two different inks and control data for controlling printing of the dot data, the printhead module including a communication input for receiving the dot data for the at least two colors and the control data.

911. A printer controller according to claim 877, for supplying data to a printhead module including at least one row of printhead nozzles, at least one row including at least one displaced row portion, the displacement of the row portion including a component in a direction normal to that of a pagewidth to be printed.

912. A printer controller according to claim 877, for supplying data to a printhead module having a plurality of rows of nozzles configured to extend, in use, across at least part of a printable pagewidth, the nozzles in each row being grouped into at least first and second fire groups, the printhead module being configured to sequentially fire, for each row, the nozzles of each fire group, such that each nozzle in the sequence from each fire group is fired simultaneously with respective corresponding nozzles in the sequence in the other fire groups, wherein the nozzles are fired row by row such that the nozzles of each row are all fired before the nozzles of each subsequent row.

913. A printer controller according to claim 877, for supplying data to a printhead module comprising at least first and second rows configured to print ink of a similar type or color, at least some nozzles in the first row being aligned with respective corresponding nozzles in the second row in a direction of intended media travel relative to the printhead, the printhead module being configurable such that the nozzles in the first and second pairs of rows are fired such that some dots output to print media are printed to by nozzles from the first pair of rows and at least some other dots output to print media are printed to by nozzles from the second pair of rows.

914. A printer controller according to claim 877, for providing data to a printhead module that includes:
at least one row of print nozzles;
at least first and second shift registers for shifting in dot data supplied from a data source, wherein each shift register feeds dot data to a group of nozzles, and wherein each of the groups of the nozzles is interleaved with at least one of the other groups of the nozzles.

915. A printer controller according to claim 877, for supplying data to a printhead module having a plurality of nozzles for expelling ink, the printhead module including a plurality of thermal sensors, each of the thermal sensors being configured to respond to a temperature at or adjacent at least one of the nozzles, the printhead module being configured to modify operation of the nozzles in response to the temperature rising above a first threshold.

916. A printer controller according to claim 877, for supplying data to a printhead module comprising a plurality of rows, each of the rows comprising a plurality of nozzles for ejecting ink, wherein the printhead module includes at least first and second rows configured to print ink of a similar type or color, and being configured such that, in the event a nozzle in the first row is faulty, a corresponding nozzle in the second row prints an ink dot at a position on print media at or adjacent a position where the faulty nozzle would otherwise have printed it.

917. A printer controller for receiving first data and manipulating the first data to produce dot data to be printed, the print controller including at least two serial outputs for supplying the dot data to at least one printhead, wherein each of the serial outputs is configured to supply dot data for at least two channels of the at least one printhead.

918. A printer controller according to claim 917, wherein the at least two channels include at least two color channels.

919. A printer controller according to claim 917, wherein the at least two channels include at least one fixative channel.

920. A printer controller according to claim 917, wherein the at least two channels include at least one infrared ink channel.

921. A printer controller according to claim 917, wherein the first data includes one or more instructions associated with production of the dot data from the first data, the print controller including processing means for producing the dot data from the first data on the basis of the one or more instructions.

922. A printer controller according to claim 917, wherein the printhead is a pagewidth printhead.

923. A printer controller according to claim 917, for implementing a method of at least partially compensating for errors in ink dot placement by at least one of a plurality of nozzles due to erroneous rotational displacement of a printhead module relative to a carrier, the nozzles being disposed on the printhead module, the method comprising the steps of:

determining the rotational displacement;
determining at least one correction factor that at least partially compensates for the ink dot displacement; and using the correction factor to alter the output of the ink dots to at least partially compensate for the rotational displacement.

924. A printer controller according to claim 917 for implementing a method of expelling ink from a printhead module including at least one row that comprises a plurality of adjacent sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, the method comprising providing, for each set of nozzles, a fire signal in accordance with the sequence: [nozzle position 1, nozzle position n, nozzle position 2, nozzle position (n-1), ... , nozzle position x], wherein nozzle position x is at or adjacent the centre of the set of nozzles.

925. A printer controller according to claim 917, for implementing a method of expelling ink from a printhead module including at least one row that comprises a plurality of sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, the method comprising the steps of:
(a). providing a fire signal to nozzles at a first and nth position in each set of nozzles;
(b). providing a fire signal to the next inward pair of nozzles in each set;
in the event n is an even number, repeating step (b) until all of the nozzles in each set has been fired; and in the event n is an odd number, repeating step (b) until all of the nozzles but a central nozzle in each set have been fired, and then firing the central nozzle.

926. A printer controller according to claim 917, manufactured in accordance with a method of manufacturing a plurality of printhead modules, at least some of which are capable of being combined in pairs to form bilithic pagewidth printheads, the method comprising the step of laying out each of the plurality of printhead modules on a wafer substrate, wherein at least one of the printhead modules is right-handed and at least another is left-handed.

927. A printer controller according to claim 917, for supplying data to a printhead module including:
at least one row of print nozzles;
at least two shift registers for shifting in dot data supplied from a data source to each of the at least one rows, wherein each print nozzle obtains dot data to be fired from an element of one of the shift registers.

928. A printer controller according to claim 917, installed in a printer comprising:
a printhead comprising at least a first elongate printhead module, the at least one printhead module including at least one row of print nozzles for expelling ink; and at least first and second printer controllers configured to receive print data and process the print data to output dot data to the printhead, wherein the first and second printer controllers are connected to a common input of the printhead.

929. A printer controller according to claim 917, installed in a printer comprising:
a printhead comprising first and second elongate printhead modules, the printhead modules being parallel to each other and being disposed end to end on either side of a join region;
at least first and second printer controllers configured to receive print data and process the print data to output dot data to the printhead, wherein the first printer controller outputs dot data only to the fust printhead module and the second printer controller outputs dot data only to the second printhead module, wherein the printhead modules are configured such that no dot data passes between them.

930. A printer controller according to claim 917, installed in a printer comprising:
a printhead comprising first and second elongate printhead modules, the printhead modules being parallel to each other and being disposed end to end on either side of a join region, wherein the first printhead module is longer than the second printhead module;
at least first and second printer controllers configured to receive print data and process the print data to output dot data to the printhead, wherein: the first printer controller outputs dot data to both the first printhead module and the second printhead module; and the second printer controller outputs dot data only to the second printhead module.

931. A printer controller according to claim 917, installed in a printer comprising:
a printhead comprising first and second elongate printhead modules, the printhead modules being parallel to each other and being disposed end to end on either side of a join region, wherein the first printhead module is longer than the second printhead module;
at least first and second printer controllers configured to receive print data and process the print data to output dot data for the printhead, wherein: the first printer controller outputs dot data to both the first printhead module and the second controller; and the second printer controller outputs dot data to the second printhead module, wherein the dot data output by the second printer controller includes dot data it generates and at least some of the dot data received from the first printer controller.

932. A printer controller according to claim 917, for supplying dot data to at least one printhead module and at least partially compensating for errors in ink dot placement by at least one of a plurality of nozzles on the printhead module due to erroneous rotational displacement of the printhead module relative to a carrier, the printer being configured to:
access a correction factor associated with the at least one printhead module;

determine an order in which at least some of the dot data is supplied to at least one of the at least one printhead modules, the order being determined at least partly on the basis of the correction factor, thereby to at least partially compensate for the rotational displacement; and supply the dot data to the printhead module.

933. A printer controller according to claim 917, for supplying dot data to a printhead module having a plurality of nozzles for expelling ink, the printhead module including a plurality of thermal sensors, each of the thermal sensors being configured to respond to a temperature at or adjacent at least one of the nozzles, the printer controller being configured to modify operation of at least some of the nozzles in response to the temperature rising above a first threshold.

934. A printer controller according to claim 917, for controlling a printhead comprising at least one monolithic printhead module, the at least one printhead module having a plurality of rows of nozzles configured to extend, in use, across at least part of a printable pagewidth of the printhead, the nozzles in each row being grouped into at least first and second fire groups, the printhead module being configured to sequentially fire, for each row, the nozzles of each fire group, such that each nozzle in the sequence from each fire group is fired simultaneously with respective corresponding nozzles in the sequence in the other fire groups, wherein the nozzles are fired row by row such that the nozzles of each row are all fired before the nozzles of each subsequent row, wherein the printer controller is configured to provide one or more control signals that control the order of firing of the nozzles.

935. A printer controller according to claim 917, for outputting to a printhead module:
dot data to be printed with at least two different inks; and control data for controlling printing of the dot data;
the printer controller including at least one communication output, each or the communication output being configured to output at least some of the control data and at least some of the dot data for the at least two inks.

936. A printer controller according to claim 917, for supplying data to a printhead module including at least one row of printhead nozzles, at least one row including at least one displaced row portion, the displacement of the row portion including a component in a direction normal to that of a pagewidth to be printed.

937. A printer controller according to claim 917, for supplying print data to at least one printhead module capable of printing a maximum of n of channels of print data, the at least one printhead module being configurable into:
a first mode, in which the printhead module is configured to receive data for a first number of the channels; and a second mode, in which the printhead module is configured to receive print data for a second number of the channels, wherein the first number is greater than the second number;

wherein the printer controller is selectively configurable to supply dot data for the first and second modes.

938. A printer controller according to claim 917, for supplying data to a printhead comprising a plurality of printhead modules, the printhead being wider than a reticle step used in forming the modules, the printhead comprising at least two types of the modules, wherein each type is determined by its geometric shape in plan.

939. A printer controller according to claim 917, for supplying one or more control signals to a printhead module, the printhead module including at least one row that comprises a plurality of sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, such that:
(a). a fire signal is provided to nozzles at a first and nth position in each set of nozzles;
(b). a fire signal is provided to the next inward pair of nozzles in each set;
(c). in the event n is an even number, step (b) is repeated until all of the nozzles in each set has been fired;
and (d). in the event n is an odd number, step (b) is repeated until all of the nozzles but a central nozzle in each set have been fired, and then the central nozzle is fired.

940. A printer controller according to claim 917, for supplying one or more control signals to a printhead module, the printhead module including at least one row that comprises a plurality of adjacent sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, the method comprising providing, for each set of nozzles, a fire signal in accordance with the sequence: [nozzle position 1, nozzle position n, nozzle position 2, nozzle position (n-1), ... , nozzle position x], wherein nozzle position x is at or adjacent the centre of the set of nozzles.

941. A printer controller according to claim 917, for supplying dot data to a printhead module comprising at least f rst and second rows configured to print ink of a similar type or color, at least some nozzles in the first row being aligned with respective corresponding nozzles in the second row in a direction of intended media travel relative to the printhead, the printhead module being configurable such that the nozzles in the first and second pairs of rows are fired such that some dots output to print media are printed to by nozzles from the first pair of rows and at least some other dots output to print media are printed to by nozzles from the second pair of rows, the printer controller being configurable to supply dot data to the printhead module for printing.

942. A printer controller according to claim 917, for supplying dot data to at least one printhead module, the at least one printhead module comprising a plurality of rows, each of the rows comprising a plurality of nozzles for ejecting ink, wherein the printhead module includes at least first and second rows configured to print ink of a similar type or color, the printer controller being configured to supply the dot data to the at least one printhead module such that, in the event a nozzle in the first row is faulty, a corresponding nozzle in the second row prints an ink dot at a position on print media at or adjacent a position where the faulty nozzle would otherwise have printed it.

943. A printer controller according to claim 917, for supplying data to a printhead module including:
at least one row of print nozzles;
at least first and second shift registers for shifting in dot data supplied from a data source, wherein each shift register feeds dot data to a group of nozzles, and wherein each of the groups of the nozzles is interleaved with at least one of the other groups of the nozzles.

944. A printer controller according to claim 917, for supplying data to a printhead capable of printing a maximum of n of channels of print data, the printhead being configurable into:
a first mode, in which the printhead is configured to receive print data for a first number of the channels; and second mode, in which the printhead is configured to receive print data for a second number of the channels, wherein the first number is greater than the second number.

945. A printer controller according to claim 917, for supplying data to a printhead comprising a plurality of printhead modules, the printhead being wider than a reticle step used in forming the modules, the printhead comprising at least two types of the modules, wherein each type is determined by its geometric shape in plan.

946. A printer controller according to claim 917, for supplying data to a printhead module including at least one row that comprises a plurality of sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, such that, for each set of nozzles, a fire signal is provided in accordance with the sequence: [nozzle position 1, nozzle position n, nozzle position 2, nozzle position (n-1), ... , nozzle position x], wherein nozzle position x is at or adjacent the centre of the set of nozzles.

947. A printer controller according to claim 917, for supplying data to a printhead module including at least one row that comprises a plurality of adjacent sets of n adjacent nozzles, each of the nozzles being configured to expel the ink in response to a fire signal, the printhead being configured to output ink from nozzles at a first and nth position in each set of nozzles, and then each next inward pair of nozzles in each set, until:
in the event n is an even number, all of the nozzles in each set has been fired; and in the event n is an odd number, all of the nozzles but a central nozzle in each set have been fired, and then to fire the central nozzle.

948. A printer controller according to claim 917, for supplying data to a printhead module for receiving dot data to be printed using at least two different inks and control data for controlling printing of the dot data, the printhead module including a communication input for receiving the dot data for the at least two colors and the control data.

949. A printer controller according to claim 917, for supplying data to a printhead module including at least one row of printhead nozzles, at least one row including at least one displaced row portion, the displacement of the row portion including a component in a direction normal to that of a pagewidth to be printed.

950. A printer controller according to claim 917, for supplying data to a printhead module having a plurality of rows of nozzles configured to extend, in use, across at least part of a printable pagewidth, the nozzles in each row being grouped into at least first and second fire groups, the printhead module being configured to sequentially fire, for each row, the nozzles of each fire group, such that each nozzle in the sequence from each fire group is fired simultaneously with respective corresponding nozzles in the sequence in the other fire groups, wherein the nozzles are fired row by row such that the nozzles of each row are all fired before the nozzles of each subsequent row.

951. A printer controller according to claim 917, for supplying data to a printhead module comprising at least first and second rows configured to print ink of a similar type or color, at least some nozzles in the first row being aligned with respective corresponding nozzles in the second row in a direction of intended media travel relative to the printhead, the printhead module being configurable such that the nozzles in the first and second pairs of rows are fired such that some dots output to print media are printed to by nozzles from the first pair of rows and at least some other dots output to print media are printed to by nozzles from the second pair of rows.

952. A printer controller according to claim 917, for providing data to a printhead module that includes:
at least one row of print nozzles;
at least first and second shift registers for shifting in dot data supplied from a data source, wherein each shift register feeds dot data to a group of nozzles, and wherein each of the groups of the nozzles is interleaved with at least one of the other groups of the nozzles.

953. A printer controller according to claim 917, for supplying data to a printhead module having a plurality of nozzles for expelling ink, the printhead module including a plurality of thermal sensors, each of the thermal sensors being configured to respond to a temperature at or adjacent at least one of the nozzles, the printhead module being configured to modify operation of the nozzles in response to the temperature rising above a first threshold.

954. A printer controller according to claim 917, for supplying data to a printhead module comprising a plurality of rows, each of the rows comprising a plurality of nozzles for ejecting ink, wherein the printhead module includes at least first and second rows configured to print ink of a similar type or color, and being configured such that, in the event a nozzle in the first row is faulty, a corresponding nozzle in the second row prints an ink dot at a position on print media at or adjacent a position where the faulty nozzle would otherwise have printed it.

955. A printhead module including:
at least one row of print nozzles;
at least first and second shift registers for shifting in dot data supplied from a data source, wherein each shift register feeds dot data to a group of nozzles, and wherein each of the groups of the nozzles is interleaved with at least one of the other groups of the nozzles.

956. A printhead module according to claim 955, wherein there is a one to one correspondence between the nozzles and respective elements of the first and second shift registers.

957. A printhead module according to claim 956, wherein each of the shift registers supplies dot data to about half of the nozzles in a row.

958. A printhead module according to claim 955, including at least one pair of rows of the nozzles, the rows in each pair being offset in a direction parallel to the rows by half the intra-row nozzle spacing.

959. A printhead module according to claim 959, wherein each of the at least two shift registers supplies dot data to at least some of the nozzles in at least the pair of rows.

960. A printhead module according claim 955, including a plurality of the rows configured to print using at least two ink channels, the nozzles for each of the ink channels being fed the dot data from at least one pair of first and second registers.

961. A printhead module according to claim 955, configured to receive dot data to which a method of at least partially compensating for errors in ink dot placement by at least one of a plurality of nozzles due to erroneous rotational displacement of a printhead module relative to a carrier has been applied, the nozzles being disposed on the printhead module, the method comprising the steps of:
determining the rotational displacement;
determining at least one correction factor that at least partially compensates for the ink dot displacement; and using the correction factor to alter the output of the ink dots to at least partially compensate for the rotational displacement.

962. A printhead module according to claim 955, configured to receive dot data to which a method of expelling ink has been applied, the method being applied to a printhead module including at least one row that comprises a plurality of adjacent sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, the method comprising providing, for each set of nozzles, a fire signal in accordance with the sequence: [nozzle position 1, nozzle position n, nozzle position 2, nozzle position (n-1), ... , nozzle position x], wherein nozzle position x is at or adjacent the centre of the set of nozzles.

963. A printhead module according to claim 955, configured to receive dot data to which a method of expelling ink has been applied, the method being applied to a printhead module including at least one row that comprises a plurality of sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, the method comprising the steps of (a). providing a fire signal to nozzles at a first and nth position in each set of nozzles;
(b). providing a fire signal to the next inward pair of nozzles in each set;
(c). in the event n is an even number, repeating step (b) until all of the nozzles in each set has been fired; and (d). in the event n is an odd number, repeating step (b) until all of the nozzles but a central nozzle in each set have been fired, and then firing the central nozzle.

964. A printhead module according to claim 955, having been manufactured in accordance with a method of manufacturing a plurality of printhead modules, at least some of which are capable of being combined in pairs to form bilithic pagewidth printheads, the method comprising the step of laying out each of the plurality of printhead modules on a wafer substrate, wherein at least one of the printhead modules is right-handed and at least another is left-handed.

965. A printhead module according to claim 955, including:
at least one row of print nozzles;
at least two shift registers for shifting in dot data supplied from a data source to each of the at least one rows, wherein each print nozzle obtains dot data to be fired from an element of one of the shift registers.

966. A printhead module according to claim 955, installed in a printer comprising:
a printhead comprising at least the first elongate printhead module, the at least one printhead module including at least one row of print nozzles for expelling ink; and at least first and second printer controllers configured to receive print data and process the print data to output dot data to the printhead, wherein the first and second printer controllers are connected to a common input of the printhead.

967. A printhead module according to claim 955, installed in a printer comprising:
a printhead comprising first and second elongate printhead modules, the printhead modules being parallel to each other and being disposed end to end on either side of a join region;
at least first and second printer controllers configured to receive print data and process the print data to output dot data to the printhead, wherein the first printer controller outputs dot data only to the first printhead module and the second printer controller outputs dot data only to the second printhead module, wherein the printhead modules are configured such that no dot data passes between them.

968. A printhead module according to claim 955, installed in a printer comprising:
a printhead comprising first and second elongate printhead modules, the printhead modules being parallel to each other and being disposed end to end on either side of a join region, wherein the first printhead module is longer than the second printhead module;
at least first and second printer controllers configured to receive print data and process the print data to output dot data to the printhead, wherein: the first printer controller outputs dot data to both the first printhead module and the second printhead module; and the second printer controller outputs dot data only to the second printhead module.

969. A printhead module according to claim 955, installed in a printer comprising:
a printhead comprising first and second elongate printhead modules, the printhead modules being parallel to each other and being disposed end to end on either side of a join region, wherein the first printhead module is longer than the second printhead module;
at least first and second printer controllers configured to receive print data and process the print data to output dot data for the printhead, wherein: the first printer controller outputs dot data to both the first printhead module and the second controller; and the second printer controller outputs dot data to the second printhead module, wherein the dot data output by the second printer controller includes dot data it generates and at least some of the dot data received from the first printer controller.

970. A printhead module according to claim 955, in communication with a printer controller for supplying dot data to at least one printhead module and at least partially compensating for errors in ink dot placement by at least one of a plurality of nozzles on the printhead module due to erroneous rotational displacement of the printhead module relative to a carrier, the printer being configured to:
access a correction factor associated with the at least one printhead module;
determine an order in which at least some of the dot data is supplied to at least one of the at least one printhead modules, the order being determined at least partly on the basis of the correction factor, thereby to at least partially compensate for the rotational displacement; and supply the dot data to the printhead module.

971. A printhead module according to claim 955, in communication with a printer controller for supplying dot data to a printhead module having a plurality of nozzles for expelling ink, the printhead module including a plurality of thermal sensors, each of the thermal sensors being configured to respond to a temperature at or adjacent at least one of the nozzles, the printer controller being configured to modify operation of at least some of the nozzles in response to the temperature rising above a first threshold.

972. A printhead module according to claim 955, in communication with a printer controller for controlling a head comprising at least one monolithic printhead module, the at least one printhead module having a plurality of rows of nozzles configured to extend, in use, across at least part of a printable pagewidth of the printhead, the nozzles in each row being grouped into at least first and second fire groups, the printhead module being configured to sequentially fire, for each row, the nozzles of each fire group, such that each nozzle in the sequence from each fire group is fired simultaneously with respective corresponding nozzles in the sequence in the other fire groups, wherein the nozzles are fired row by row such that the nozzles of each row are all fired before the nozzles of each subsequent row, wherein the printer controller is configured to provide one or more control signals that control the order of firing of the nozzles.

973. A printhead module according to claim 955, in communication with a printer controller for outputting to a printhead module:
dot data to be printed with at least two different inks; and control data for controlling printing of the dot data;
the printer controller including at least one communication output, each or the communication output being configured to output at least some of the control data and at least some of the dot data for the at least two inks.

974. A printhead module according to claim 955, including at least one row of printhead nozzles, at least one row including at least one displaced row portion, the displacement of the row portion including a component in a direction normal to that of a pagewidth to be printed.

975. A printhead module according to claim 955, in communication with a printer controller for supplying print data to at least one printhead module capable of printing a maximum of n of channels of print data, the at least one printhead module being configurable into:
a first mode, in which the printhead module is configured to receive data for a first number of the channels; and a second mode, in which the printhead module is configured to receive print data for a second number of the channels, wherein the first number is greater than the second number;
wherein the printer controller is selectively configurable to supply dot data for the first and second modes.

976. A printhead module according to claim 955, in communication with a printer controller for supplying data to a printhead comprising a plurality of printhead modules, the printhead being wider than a reticle step used in forming the modules, the printhead comprising at least two types of the modules, wherein each type is determined by its geometric shape in plan.

977. A printhead module according to claim 955, used in conjunction with a printer controller for supplying one or more control signals to a printhead module, the printhead module including at least one row that comprises a plurality of sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, such that:
(a). a fire signal is provided to nozzles at a first and nth position in each set of nozzles;
(b). a fire signal is provided to the next inward pair of nozzles in each set;
(c). in the event n is an even number, step (b) is repeated until all of the nozzles in each set has been fired;
and (d). in the event n is an odd number, step (b) is repeated until all of the nozzles but a central nozzle in each set have been fired, and then the central nozzle is fired.

978. A printhead module according to claim 955, used in conjunction with a printer controller for supplying one or more control signals to a printhead module, the printhead module including at least one row that comprises a plurality of adjacent sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, the method comprising providing, for each set of nozzles, a fire signal in accordance with the sequence: [nozzle position 1, nozzle position n, nozzle position 2, nozzle position (n-1), ... , nozzle position x], wherein nozzle position x is at or adjacent the centre of the set of nozzles.

979. A printhead module according to claim 955, in communication with a printer controller for supplying dot data to a printhead module comprising at least first and second rows configured to print ink of a similar type or color, at least some nozzles in the first row being aligned with respective corresponding nozzles in the second row in a direction of intended media travel relative to the printhead, the printhead module being configurable such that the nozzles in the first and second pairs of rows are fired such that some dots output to print media are printed to by nozzles from the first pair of rows and at least some other dots output to print media are printed to by nozzles from the second pair of rows, the printer controller being configurable to supply dot data to the printhead module for printing.

980. A printhead module according to claim 955, in communication with a printer controller for supplying dot data to at least one printhead module, the at least one printhead module comprising a plurality of rows, each of the rows comprising a plurality of nozzles for ejecting ink, wherein the printhead module includes at least first and second rows configured to print ink of a similar type or color, the printer controller being configured to supply the dot data to the at least one printhead module such that, in the event a nozzle in the first row is faulty, a corresponding nozzle in the second row prints an ink dot at a position on print media at or adjacent a position where the faulty nozzle would otherwise have printed it.

981. A printhead module according to claim 955, in communication with a printer controller for receiving first data and manipulating the first data to produce dot data to be printed, the print controller including at least two serial outputs for supplying the dot data to at least one printhead.

982. A printhead module according to claim 955, including:
at least one row of print nozzles;
at least first and second shift registers for shifting in dot data supplied from a data source, wherein each shift register feeds dot data to a group of nozzles, and wherein each of the groups of the nozzles is interleaved with at least one of the other groups of the nozzles.

983. A printhead module according to claim 955 being capable of printing a maximum of n of channels of print data, the printhead being configurable into:
a fust mode, in which the printhead is configured to receive print data for a first number of the channels; and a second mode, in which the printhead is configured to receive print data for a second number of the channels, wherein the first number is greater than the second number.

984. A printhead comprising a plurality of printhead modules according to claim 955, the printhead being wider than a reticle step used in forming the modules, the printhead comprising at least two types of the modules, wherein each type is determined by its geometric shape in plan.

985. A printhead module according to claim 955, including at least one row that comprises a plurality of sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, such that, for each set of nozzles, a fire signal is provided in accordance with the sequence: [nozzle position 1, nozzle position n, nozzle position 2, nozzle position (n-1), ... , nozzle position x], wherein nozzle position x is at or adjacent the centre of the set of nozzles.

986. A printhead module according to claim 955, including at least one row that comprises a plurality of adjacent sets of n adjacent nozzles, each of the nozzles being configured to expel the ink in response to a fire signal, the printhead being configured to output ink from nozzles at a first and nth position in each set of nozzles, and then each next inward pair of nozzles in each set, until:
in the event n is an even number, all of the nozzles in each set has been fired; and in the event n is an odd number, all of the nozzles but a central nozzle in each set have been fired, and then to fire the central nozzle.

987. A printhead module according to claim 955, for receiving dot data to be printed using at least two different inks and control data for controlling printing of the dot data, the printhead module including a communication input for receiving the dot data for the at least two colors and the control data.

988. A printhead module according to claim 955, including at least one row of printhead nozzles, at least one row including at least one displaced row portion, the displacement of the row portion including a component in a direction normal to that of a pagewidth to be printed.

989. A printhead module according to claim 955, having a plurality of rows of nozzles configured to extend, in use, across at least part of a printable pagewidth, the nozzles in each row being grouped into at least first and second fire groups, the printhead module being configured to sequentially fire, for each row, the nozzles of each fire group, such that each nozzle in the sequence from each fire group is fired simultaneously with respective corresponding nozzles in the sequence in the other fire groups, wherein the nozzles are fired row by row such that the nozzles of each row are all fired before the nozzles of each subsequent row.

990. A printhead module according to claim 955, comprising at least first and second rows configured to print ink of a similar type or color, at least some nozzles in the first row being aligned with respective corresponding nozzles in the second row in a direction of intended media travel relative to the printhead, the printhead module being configurable such that the nozzles in the first and second pairs of rows are fired such that some dots output to print media are printed to by nozzles from the first pair of rows and at least some other dots output to print media are printed to by nozzles from the second pair of rows.

991. A printhead module according to claim 955, in communication with a printer controller for providing data to a printhead module that includes:
at least one row of print nozzles;
at least first and second shift registers for shifting in dot data supplied from a data source, wherein each shift register feeds dot data to a group of nozzles, and wherein each of the groups of the nozzles is interleaved with at least one of the other groups of the nozzles.

992. A printhead module according to claim 955, having a plurality of nozzles for expelling ink, the printhead module including a plurality of thermal sensors, each of the thermal sensors being configured to respond to a temperature at or adjacent at least one of the nozzles, the printhead module being configured to modify operation of the nozzles in response to the temperature rising above a first threshold.

993. A printhead module according to claim 955, comprising a plurality of rows, each of the rows comprising a plurality of nozzles for ejecting ink, wherein the printhead module includes at least first and second rows configured to print ink of a similar type or color, and being configured such that, in the event a nozzle in the first row is faulty, a corresponding nozzle in the second row prints an ink dot at a position on print media at or adjacent a position where the faulty nozzle would otherwise have printed it.

994. A printhead module capable of printing a maximum of n of channels of print data, the printhead module being configurable into:
a first mode, in which the printhead module is configured to receive print data for a first number of the channels;
and a second mode, in which the printhead module is configured to receive print data for a second number of the channels, wherein the first number is greater than the second number.

995. A printhead module according to claim 994, wherein the first number is n.

996. A printhead module according to claim 994, wherein the first number is less than n.

997. A printhead module according to claim 994, configurable into at least one other mode, in which the printhead is configured to receive print data for a number of print channels other than the first and second numbers.

998. A printhead module according to claim 994, wherein n is 4 and the second number is less than 4.

999. A printhead module according to claim 994, wherein n is 5 and the second number is less than 5.

1000. A printhead module according to claim 994, wherein n is 6 and the second number is less than 6.

1001. A printhead module according to claim 1000, wherein the second number is 3, 4 or 5.

1002. A printhead module according to claim 994, wherein the selected mode is selected based on the contents of a memory associated with the printhead.

1003. A printhead module according to claim 1002, wherein the memory is a register.

1004. A printhead module according to claim 1002, wherein the register is on an integrated circuit, and wherein the integrated circuit and the printhead are mounted to a print engine.

1005. A printhead according to claim 994, comprising a plurality of printhead modules.

1006. A printhead according to claim 1005, wherein the printhead is a pagewidth printhead.

1007. A printhead module according to claim 994, configured to receive dot data to which a method of at least partially compensating for errors in ink dot placement by at least one of a plurality of nozzles due to erroneous rotational displacement of a printhead module relative to a carrier has been applied, the nozzles being disposed on the printhead module, the method comprising the steps of:
determining the rotational displacement;
determining at least one correction factor that at least partially compensates for the ink dot displacement; and using the correction factor to alter the output of the ink dots to at least partially compensate for the rotational displacement.

1008. A printhead module according to claim 994, configured to receive dot data to which a method of expelling ink has been applied, the method being applied to a printhead module including at least one row that comprises a plurality of adjacent sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, the method comprising providing, for each set of nozzles, a fire signal in accordance with the sequence: [nozzle position 1, nozzle position n, nozzle position 2, nozzle position (n-1), ... , nozzle position x], wherein nozzle position x is at or adjacent the centre of the set of nozzles.

1009. A printhead module according to claim 994, configured to receive dot data to which a method of expelling ink has been applied, the method being applied to a printhead module including at least one row that comprises a plurality of sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, the method comprising the steps of:
(a). providing a fire signal to nozzles at a first and nth position in each set of nozzles;
(b). providing a fire signal to the next inward pair of nozzles in each set;
(c). in the event n is an even number, repeating step (b) until all of the nozzles in each set has been fired; and (d), in the event n is an odd number, repeating step (b) until all of the nozzles but a central nozzle in each set have been fired, and then firing the central nozzle.

1010. A printhead module according to claim 994, having been manufactured in accordance with a method of manufacturing a plurality of printhead modules, at least some of which are capable of being combined in pairs to form bilithic pagewidth printheads, the method comprising the step of laying out each of the plurality of printhead modules on a wafer substrate, wherein at least one of the printhead modules is right-handed and at least another is left-handed.

1011. A printhead module according to claim 994, including:
at least one row of print nozzles;
at least two shift registers for shifting in dot data supplied from a data source to each of the at least one rows, wherein each print nozzle obtains dot data to be fired from an element of one of the shift registers.

1012. A printhead module according to claim 994, installed in a printer comprising:
a printhead comprising at least the first elongate printhead module, the at least one printhead module including at least one row of print nozzles for expelling ink; and at least first and second printer controllers configured to receive print data and process the print data to output dot data to the printhead, wherein the first and second printer controllers are connected to a common input of the printhead.

1013. A printhead module according to claim 994, installed in a printer comprising:
a printhead comprising first and second elongate printhead modules, the printhead modules being parallel to each other and being disposed end to end on either side of a join region;
at least first and second printer controllers configured to receive print data and process the print data to output dot data to the printhead, wherein the first printer controller outputs dot data only to the first printhead module and the second printer controller outputs dot data only to the second printhead module, wherein the printhead modules are configured such that no dot data passes between them.

1014. A printhead module according to claim 994, installed in a printer comprising:
a printhead comprising first and second elongate printhead modules, the printhead modules being parallel to each other and being disposed end to end on either side of a join region, wherein the first printhead module is longer than the second printhead module;
at least first and second printer controllers configured to receive print data and process the print data to output dot data to the printhead, wherein: the first printer controller outputs dot data to both the first printhead module and the second printhead module; and the second printer controller outputs dot data only to the second printhead module.

1015. A printhead module according to claim 994, installed in a printer comprising:
a printhead comprising first and second elongate printhead modules, the printhead modules being parallel to each other and being disposed end to end on either side of a join region, wherein the first printhead module is longer than the second printhead module;
at least first and second printer controllers configured to receive print data and process the print data to output dot data for the printhead, wherein: the first printer controller outputs dot data to both the first printhead module and the second controller; and the second printer controller outputs dot data to the second printhead module, wherein the dot data output by the second printer controller includes dot data it generates and at least some of the dot data received from the first printer controller.

1016. A printhead module according to claim 994, in communication with a printer controller for supplying dot data to at least one printhead module and at least partially compensating for errors in ink dot placement by at least one of a plurality of nozzles on the printhead module due to erroneous rotational displacement of the printhead module relative to a carrier, the printer being configured to:
access a correction factor associated with the at least one printhead module;
determine an order in which at least some of the dot data is supplied to at least one of the at least one printhead modules, the order being determined at least partly on the basis of the correction factor, thereby to at least partially compensate for the rotational displacement; and supply the dot data to the printhead module.

1017. A printhead module according to claim 994, in communication with a printer controller for supplying dot data to a printhead module having a plurality of nozzles for expelling ink, the printhead module including a plurality of thermal sensors, each of the thermal sensors being configured to respond to a temperature at or adjacent at least one of the nozzles, the printer controller being configured to modify operation of at least some of the nozzles in response to the temperature rising above a first threshold.

1018. A printhead module according to claim 994, in communication with a printer controller for controlling a head comprising at least one monolithic printhead module, the at least one printhead module having a plurality of rows of nozzles configured to extend, in use, across at least part of a printable pagewidth of the printhead, the nozzles in each row being grouped into at least first and second fire groups, the printhead module being configured to sequentially fire, for each row, the nozzles of each fire group, such that each nozzle in the sequence from each fire group is fired simultaneously with respective corresponding nozzles in the sequence in the other fire groups, wherein the nozzles are fired row by row such that the nozzles of each row are all fired before the nozzles of each subsequent row, wherein the printer controller is configured to provide one or more control signals that control the order of firing of the nozzles.

1019. A printhead module according to claim 994, in communication with a printer controller for outputting to a printhead module:
dot data to be printed with at least two different inks; and control data for controlling printing of the dot data;
the printer controller including at least one communication output, each or the communication output being configured to output at least some of the control data and at least some of the dot data for the at least two inks.

1020. A printhead module according to claim 994, including at least one row of printhead nozzles, at least one row including at least one displaced row portion, the displacement of the row portion including a component in a direction normal to that of a pagewidth to be printed.

1021. A printhead module according to claim 994, in communication with a printer controller for supplying print data to at least one printhead module capable of printing a maximum of n of channels of print data, the at least one printhead module being configurable into:
a first mode, in which the printhead module is configured to receive data for a first number of the channels; and a second mode, in which the printhead module is configured to receive print data for a second number of the channels, wherein the first number is greater than the second number;
wherein the printer controller is selectively configurable to supply dot data for the first and second modes.

1022. A printhead module according to claim 994, in communication with a printer controller for supplying data to a printhead comprising a plurality of printhead modules, the printhead being wider than a reticle step used in forming the modules, the printhead comprising at least two types of the modules, wherein each type is determined by its geometric shape in plan.

1023. A printhead module according to claim 994, used in conjunction with a printer controller for supplying one or more control signals to a printhead module, the printhead module including at least one row that comprises a plurality of sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, such that:
(a). a fire signal is provided to nozzles at a first and nth position in each set of nozzles;
(b). a fire signal is provided to the next inward pair of nozzles in each set;
(c). in the event n is an even number, step (b) is repeated until all of the nozzles in each set has been fired;
and (d). in the event n is an odd number, step (b) is repeated until all of the nozzles but a central nozzle in each set have been fired, and then the central nozzle is fired.

1024. A printhead module according to claim 994, used in conjunction with a printer controller for supplying one or more control signals to a printhead module, the printhead module including at Ieast one row that comprises a plurality of adjacent sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, the method comprising providing, for each set of nozzles, a fire signal in accordance with the sequence: [nozzle position 1, nozzle position n, nozzle position 2, nozzle position (n-1), ... , nozzle position x], wherein nozzle position x is at or adjacent the centre of the set of nozzles.

1025. A printhead module according to claim 994, in communication with a printer controller for supplying dot data to a printhead module comprising at least first and second rows configured to print ink of a similar type or color, at least some nozzles in the first row being aligned with respective corresponding nozzles in the second row in a direction of intended media travel relative to the printhead, the printhead module being configurable such that the nozzles in the first and second pairs of rows are fired such that some dots output to print media are printed to by nozzles from the first pair of rows and at least some other dots output to print media are printed to by nozzles from the second pair of rows, the printer controller being configurable to supply dot data to the printhead module for printing.

1026. A printhead module according to claim 994, in communication with a printer controller for supplying dot data to at least one printhead module, the at least one printhead module comprising a plurality of rows, each of the rows comprising a plurality of nozzles for ejecting ink, wherein the printhead module includes at least first and second rows configured to print ink of a similar type or color, the printer controller being configured to supply the dot data to the at least one printhead module such that, in the event a nozzle in the first row is faulty, a corresponding nozzle in the second row prints an ink dot at a position on print media at or adjacent a position where the faulty nozzle would otherwise have printed it.

1027. A printhead module according to claim 994, in communication with a printer controller for receiving first data and manipulating the first data to produce dot data to be printed, the print controller including at least two serial outputs for supplying the dot data to at least one printhead.

1028. A printhead module according to claim 994, including:
at least one row of print nozzles;
at least first and second shift registers for shifting in dot data supplied from a data source, wherein each shift register feeds dot data to a group of nozzles, and wherein each of the groups of the nozzles is interleaved with at least one of the other groups of the nozzles.

1029. A printhead comprising a plurality of printhead modules according to claim 994, the printhead being wider than a reticle step used in forming the modules, the printhead comprising at least two types of the modules, wherein each type is determined by its geometric shape in plan.

1030. A printhead module according to claim 994, including at least one row that comprises a plurality of sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, such that, for each set of nozzles, a fire signal is provided in accordance with the sequence: [nozzle position 1, nozzle position n, nozzle position 2, nozzle position (n-1), ... , nozzle position x], wherein nozzle position x is at or adjacent the centre of the set of nozzles.

1031. A printhead module according to claim 994, including at least one row that comprises a plurality of adjacent sets of n adjacent nozzles, each of the nozzles being configured to expel the ink in response to a fire signal, the printhead being configured to output ink from nozzles at a first and nth position in each set of nozzles, and then each next inward pair of nozzles in each set, until:
in the event n is an even number, all of the nozzles in each set has been fired; and in the event n is an odd number, all of the nozzles but a central nozzle in each set have been fired, and then to fire the central nozzle.

1032. A printhead module according to claim 994, for receiving dot data to be printed using at least two different inks and control data for controlling printing of the dot data, the printhead module including a communication input for receiving the dot data for the at least two colors and the control data.

1033. A printhead module according to claim 994, including at least one row of printhead nozzles, at least one row including at least one displaced row portion, the displacement of the row portion including a component m a direction normal to that of a pagewidth to be printed.

1034. A printhead module according to claim 994, having a plurality of rows of nozzles configured to extend, in use, across at least part of a printable pagewidth, the nozzles in each row being grouped into at least first and second fire groups, the printhead module being configured to sequentially fire, for each row, the nozzles of each fire group, such that each nozzle in the sequence from each fire group is fired simultaneously with respective corresponding nozzles in the sequence in the other fire groups, wherein the nozzles are fired row by row such that the nozzles of each row are all fired before the nozzles of each subsequent row.

1035. A printhead module according to claim 994, comprising at least first and second rows configured to print ink of a similar type or color, at least some nozzles in the first row being aligned with respective corresponding nozzles in the second row in a direction of intended media travel relative to the printhead, the printhead module being configurable such that the nozzles in the first and second pairs of rows are fired such that some dots output to print media are printed to by nozzles from the first pair of rows and at least some other dots output to print media are printed to by nozzles from the second pair of rows.

1036. A printhead module according to claim 994, in communication with a printer controller for providing data to a printhead module that includes:
at least one row of print nozzles;
at least first and second shift registers for shifting in dot data supplied from a data source, wherein each shift register feeds dot data to a group of nozzles, and wherein each of the groups of the nozzles is interleaved with at least one of the other groups of the nozzles.

1037. A printhead module according to claim 994, having a plurality of nozzles for expelling ink, the printhead module including a plurality of thermal sensors, each of the thermal sensors being configured to respond to a temperature at or adjacent at least one of the nozzles, the printhead module being configured to modify operation of the nozzles in response to the temperature rising above a first threshold.

1038. A printhead module according to claim 994, comprising a plurality of rows, each of the rows comprising a plurality of nozzles for ejecting ink, wherein the printhead module includes at least first and second rows configured to print ink of a similar type or color, and being configured such that, in the event a nozzle in the first row is faulty, a corresponding nozzle in the second row prints an ink dot at a position on print media at or adjacent a position where the faulty nozzle would otherwise have printed it.

1039. A printhead comprising a plurality of printhead modules, the printhead being wider than a reticle step used in forming the modules, the printhead comprising at least two types of the modules, wherein each type is determined by its geometric shape in plan.

1040. A printhead according to claim 1039, comprising a plurality of at least one of the types of module.

1041. A printhead according to claim 1040, comprising a plurality of each of at least two of the types of module.

1042. A printhead according to claim 1039, comprising two types of the module.

1043. A printhead according to claim 1042, wherein the two types of module alternate across a print width of the printhead.

1044. A printhead according to claim 1039, each of the modules including at least one row of print nozzles, wherein each of the at least one row of print nozzles includes at least a portion that extends at an acute angle to an intended relative direction of movement between the printhead and print media.

1045. A printhead according to claim 1044, wherein the different types of modules are configured, and arranged relative to each other, such that there is substantially no growth in offset of each of the at least one row of print nozzles in a direction across an intended print width of the printhead.

1046. A printhead according to claim 1039, wherein each of the printhead modules is a monolithic integrated circuit.

1047. A printhead according to claim 1039, each of the modules including at least one row of print nozzles, wherein each of the at least one rows includes at least two sub-rows, each of the sub-rows being parallel to each other and displaced relative to each other in a direction of intended movement of print media relative to the printhead.

1048. A printhead according to claim 1039, the printhead being a pagewidth printhead.

1049. A printhead according to claim 1045, the printhead being a pagewidth printhead.

1050. A printhead according to claim 1049, the printhead being a pagewidth printhead.

1051. A printhead according to claim 1039, configured to receive dot data to which a method of at least partially compensating for errors in ink dot placement by at least one of a plurality of nozzles due to erroneous rotational displacement of a printhead module relative to a carrier has been applied, the nozzles being disposed on the printhead module, the method comprising the steps of:
determining the rotational displacement;
determining at least one correction factor that at least partially compensates for the ink dot displacement; and using the correction factor to alter the output of the ink dots to at least partially compensate for the rotational displacement.

1052. A printhead according to claim 1039, configured to receive dot data to which a method of expelling ink has been applied, the method being applied to a printhead module including at least one row that comprises a plurality of adjacent sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, the method comprising providing, for each set of nozzles, a fire signal in accordance with the sequence: [nozzle position 1, nozzle position n, nozzle position 2, nozzle position (n-1), ... , nozzle position x], wherein nozzle position x is at or adjacent the centre of the set of nozzles.

1053. A printhead according to claim 1039, configured to receive dot data to which a method of expelling ink has been applied, the method being applied to a printhead module including at least one row that comprises a plurality of sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, the method comprising the steps of:
(a). providing a fire signal to nozzles at a first and nth position in each set of nozzles;
(b). providing a fire signal to the next inward pair of nozzles in each set;
(c). in the event n is an even number, repeating step (b) until all of the nozzles in each set has been fired; and (d). in the event n is an odd number, repeating step (b) until all of the nozzles but a central nozzle in each set have been fired, and then firing the central nozzle.

1054. A printhead according to claim 1039, having been manufactured in accordance with a method of manufacturing a plurality of printhead modules, at least some of which are capable of being combined in pairs to form bilithic pagewidth printheads, the method comprising the step of laying out each of the plurality of printhead modules on a wafer substrate, wherein at least one of the printhead modules is right-handed and at least another is left-handed.

1055. A printhead according to claim 1039, including:
at least one row of print nozzles;
at least two shift registers for shifting in dot data supplied from a data source to each of the at least one rows, wherein each print nozzle obtains dot data to be fired from an element of one of the shift registers.

1056. A printhead according to claim 1039, installed in a printer comprising:
a printhead comprising at least the first elongate printhead module, the at least one printhead module including at least one row of print nozzles for expelling ink; and at least first and second printer controllers configured to receive print data and process the print data to output dot data to the printhead, wherein the first and second printer controllers are connected to a common input of the printhead.

1057. A printhead according to claim 1039, installed in a printer comprising:
a printhead comprising first and second elongate printhead modules, the printhead modules being parallel to each other and being disposed end to end on either side of a join region;
at least first and second printer controllers configured to receive print data and process the print data to output dot data to the printhead, wherein the first printer controller outputs dot data only to the first printhead module and the second printer controller outputs dot data only to the second printhead module, wherein the printhead modules are configured such that no dot data passes between them.

1058. A printhead according to claim 1039, installed in a printer comprising:
a printhead comprising first and second elongate printhead modules, the printhead modules being parallel to each other and being disposed end to end on either side of a join region, wherein the first printhead module is longer than the second printhead module;
at least first and second printer controllers configured to receive print data and process the print data to output dot data to the printhead, wherein: the first printer controller outputs dot data to both the first printhead module and the second printhead module; and the second printer controller outputs dot data only to the second printhead module.

1059. A printhead according to claim 1039, installed in a printer comprising:
a printhead comprising first and second elongate printhead modules, the printhead modules being parallel to each other and being disposed end to end on either side of a join region, wherein the first printhead module is longer than the second printhead module;
at least first and second printer controllers configured to receive print data and process the print data to output dot data for the printhead, wherein: the first printer controller outputs dot data to both the first printhead module and the second controller, and the second printer controller outputs dot data to the second printhead module, wherein the dot data output by the second printer controller includes dot data it generates and at least some of the dot data received from the first printer controller.

1060. A printhead according to claim 1039, in communication with a printer controller for supplying dot data to at least one printhead module and at least partially compensating for errors in ink dot placement by at least one of a plurality of nozzles on the printhead module due to erroneous rotational displacement of the printhead module relative to a carrier, the printer being configured to:
access a correction factor associated with the at least one printhead module;
determine an order in which at least some of the dot data is supplied to at least one of the at least one printhead modules, the order being determined at least partly on the basis of the correction factor, thereby to at least partially compensate for the rotational displacement; and supply the dot data to the printhead module.

1061. A printhead according to claim 1039, in communication with a printer controller for supplying dot data to a printhead module having a plurality of nozzles for expelling ink, the printhead module including a plurality of thermal sensors, each of the thermal sensors being configured to respond to a temperature at or adjacent at least one of the nozzles, the printer controller being configured to modify operation of at least some of the nozzles in response to the temperature rising above a first threshold.

1062. A printhead according to claim 1039, in communication with a printer controller for controlling a head comprising at least one monolithic printhead module, the at least one printhead module having a plurality of rows of nozzles configured to extend, in use, across at least part of a printable pagewidth of the printhead, the nozzles in each row being grouped into at least first and second fire groups, the printhead module being configured to sequentially fire, for each row, the nozzles of each fire group, such that each nozzle in the sequence from each fire group is fired simultaneously with respective corresponding nozzles in the sequence in the other fire groups, wherein the nozzles are fired row by row such that the nozzles of each row are all fired before the, nozzles of each subsequent row, wherein the printer controller is configured to provide one or more control signals that control the order of firing of the nozzles.

1063. A printhead according to claim 1039, in communication with a printer controller for outputting to a printhead module:
dot data to be printed with at least two different inks; and control data for controlling printing of the dot data;
the printer controller including at least one communication output, each or the communication output being configured to output at least some of the control data and at least some of the dot data for the at least two inks.

1064. A printhead according to claim 1039, including at least one row of printhead nozzles, at least one row including at least one displaced row portion, the displacement of the row portion including a component in a direction normal to that of a pagewidth to be printed.

1065. A printhead according to claim 1039, in communication with a printer controller for supplying print data to at least one printhead module capable of printing a maximum of n of channels of print data, the at least one printhead module being configurable into:
a first mode, in which the printhead module is configured to receive data for a first number of the channels; and a second mode, in which the printhead module is configured to receive print data for a second number of the channels, wherein the first number is greater than the second number;
wherein the printer controller is selectively configurable to supply dot data for the first and second modes.

1066. A printhead according to claim 1039, in communication with a printer controller for supplying data to a printhead comprising a plurality of printhead modules, the printhead being wider than a reticle step used in forming the modules, the printhead comprising at least two types of the modules, wherein each type is determined by its geometric shape in plan.

1067. A printhead according to claim 1039, used in conjunction with a printer controller for supplying one or more control signals to a printhead module, the printhead module including at least one row that comprises a plurality of sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, such that:
(a). a fire signal is provided to nozzles at a first and nth position in each set of nozzles;
(b). a fire signal is provided to the next inward pair of nozzles in each set;
(c). in the event n is an even number, step (b) is repeated until all of the nozzles in each set has been fired;
and (d). in the event n is an odd number, step (b) is repeated until all of the nozzles but a central nozzle in each set have been fired, and then the central nozzle is fired.

1068. A printhead according to claim 1039, used in conjunction with a printer controller for supplying one or more control signals to a printhead module, the printhead module including at least one row that comprises a plurality of adjacent sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, the method comprising providing, for each set of nozzles, a fire signal in accordance with the sequence: [nozzle position 1, nozzle position n, nozzle position 2, nozzle position (n-1), ... , nozzle position x], wherein nozzle position x is at or adjacent the centre of the set of nozzles.

1069. A printhead according to claim 1039, in communication with a printer controller for supplying dot data to a printhead module comprising at least first and second rows configured to print ink of a similar type or color, at least some nozzles in the first row being aligned with respective corresponding nozzles in the second row in a direction of intended media travel relative to the printhead, the printhead module being configurable such that the nozzles in the first and second pairs of rows are fired such that some dots output to print media are printed to by nozzles from the first pair of rows and at least some other dots output to print media are printed to by nozzles from the second pair of rows, the printer controller being configurable to supply dot data to the printhead module for printing.

1070. A printhead according to claim 1039, in communication with a printer controller for supplying dot data to at least one printhead module, the at least one printhead module comprising a plurality of rows, each of the rows comprising a plurality of nozzles for ejecting ink, wherein the printhead module includes at least first and second rows configured to print ink of a similar type or color, the printer controller being configured to supply the dot data to the at least one printhead module such that, in the event a nozzle in the first row is faulty, a corresponding nozzle in the second row prints an ink dot at a position on print media at or adjacent a position where the faulty nozzle would otherwise have printed it.

1071. A printhead according to claim 1039, in communication with a printer controller for receiving first data and manipulating the first data to produce dot data to be printed, the print controller including at least two serial outputs for supplying the dot data to at least one printhead.

1072. A printhead according to claim 1039, including:
at least one row of print nozzles;
at least first and second shift registers for shifting in dot data supplied from a data source, wherein each shift register feeds dot data to a group of nozzles, and wherein each of the groups of the nozzles is interleaved with at least one of the other groups of the nozzles.

1073. A printhead according to claim 1039 being capable of printing a maximum of n of channels of print data, the printhead being configurable into:
a first mode, in which the printhead is configured to receive print data for a first number of the channels; and a second mode, in which the printhead is configured to receive print data for a second number of the channels, wherein the first number is greater than the second number.

1074. A printhead according to claim 1039, including at least one row that comprises a plurality of sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, such that, for each set of nozzles, a fire signal is provided in accordance with the sequence:
[nozzle position 1, nozzle position n, nozzle position 2, nozzle position (n-1), ... , nozzle position x], wherein nozzle position x is at or adjacent the centre of the set of nozzles.

1075. A printhead according to claim 1039, including at least one row that comprises a plurality of adjacent sets of n adjacent nozzles, each of the nozzles being configured to expel the ink in response to a fire signal, the printhead being configured to output ink from nozzles at a first and nth position in each set of nozzles, and then each next inward pair of nozzles in each set, until:

in the event n is an even number, all of the nozzles in each set has been fired; and in the event n is an odd number, all of the nozzles but a central nozzle in each set have been fired, and then to fire the central nozzle.

1076. A printhead according to claim 1039, for receiving dot data to be printed using at least two different inks and control data for controlling printing of the dot data, the printhead module including a communication input for receiving the dot data for the at least two colors and the control data.

1077. A printhead according to claim 1039, including at least one row of printhead nozzles, at least one row including at least one displaced row portion, the displacement of the row portion including a component in a direction normal to that of a pagewidth to be printed.

1078. A printhead according to claim 1039, having a plurality of rows of nozzles configured to extend, in use, across at least part of a printable pagewidth, the nozzles in each row being grouped into at least first and second fire groups, the printhead being configured to sequentially fire, for each row, the nozzles of each fire group, such that each nozzle in the sequence from each fire group is fired simultaneously with respective corresponding nozzles in the sequence in the other fire groups, wherein the nozzles are fired row by row such that the nozzles of each row are all fired before the nozzles of each subsequent row.

1079. A printhead according to claim 1039, comprising at least first and second rows configured to print ink of a similar type or color, at least some nozzles in the first row being aligned with respective corresponding nozzles in the second row in a direction of intended media travel relative to the printhead, the printhead module being configurable such that the nozzles in the first and second pairs of rows are fired such that some dots output to print media are printed to by nozzles from the f rst pair of rows and at least some other dots output to print media are printed to by nozzles from the second pair of rows.

1080. A printhead according to claim 1039, in communication with a printer controller for providing data to a printhead module that includes:
at least one row of print nozzles;
at least first and second shift registers for shifting in dot data supplied from a data source, wherein each shift register feeds dot data to a group of nozzles, and wherein each of the groups of the nozzles is interleaved with at least one of the other groups of the nozzles.

1081. A printhead according to claim 1039, having a plurality of nozzles for expelling ink, the printhead module including a plurality of thermal sensors, each of the thermal sensors being configured to respond to a temperature at or adjacent at least one of the nozzles, the printhead module being configured to modify operation of the nozzles in response to the temperature rising above a first threshold.

1082. A printhead according to claim 1039, comprising a plurality of rows, each of the rows comprising a plurality of nozzles for ejecting ink, wherein the printhead module includes at least first and second rows configured to print ink of a similar type or color, and being configured such that, in the event a nozzle in the first row is faulty, a corresponding nozzle in the second row prints an ink dot at a position on print media at or adjacent a position where the faulty nozzle would otherwise have printed it.

1083. A printhead module including at least one row that comprises a plurality of sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, such that, for each set of nozzles, a fire signal is provided in accordance with the sequence: [nozzle position 1, nozzle position n, nozzle position 2, nozzle position (n-1), ... , nozzle position x], wherein nozzle position x is at or adjacent the centre of the set of nozzles.

1084. A printhead module according to claim 1083, wherein the nozzle at each given position within the set is fired simultaneously with the nozzles in the other sets at respective corresponding positions.

1085. A printhead module according to claim 1083, wherein the printhead module includes a plurality of the rows of nozzles, the printhead module being configured to fire all the nozzles on each row prior to firing any nozzles from a subsequent row.

1086. A printhead module according to claim 1084, wherein the rows are disposed in pairs.

1087. A printhead module according to claim 1085, wherein the rows in each pair of rows are offset relative to each other.

1088. A printhead module according to claim 1086, wherein each pair of rows is configured to print the same color ink.

1089. A printhead module according to claim 1087, wherein each pair of rows is connected to a common ink source.

1090. A printhead module according to claim 1083, wherein the sets of nozzles are adjacent each other.

1091. A printhead module according to claim 1083, wherein the sets of nozzles are separated by an intermediate nozzle, the intermediate nozzle being fired either prior to the nozzle at position 1 in each set, or following the nozzle at position n.

1092. A printhead comprising a plurality of printhead modules according to claim 1083.

1093. A printhead according to claim 1092, wherein the printhead is a pagewidth printhead.

1094. A printhead module according to claim 1083, configured to receive dot data to which a method of at least partially compensating for errors in ink dot placement by at least one of a plurality of nozzles due to erroneous rotational displacement of a printhead module relative to a carrier has been applied, the nozzles being disposed on the printhead module, the method comprising the steps of:
determining the rotational displacement;
determining at least one correction factor that at least partially compensates for the ink dot displacement; and using the correction factor to alter the output of the ink dots to at least partially compensate for the rotational displacement.

1095. A printhead module according to claim 1083, configured to receive dot data to which a method of expelling ink has been applied, the method being applied to a printhead module including at least one row that comprises a plurality of adjacent sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, the method comprising providing, for each set of nozzles, a fire signal in accordance with the sequence: [nozzle position 1, nozzle position n, nozzle position 2, nozzle position (n-1), ... , nozzle position x], wherein nozzle position x is at or adjacent the centre of the set of nozzles.

1096. A printhead module according to claim 1083, configured to receive dot data to which a method of expelling ink has been applied, the method being applied to a printhead module including at least one row that comprises a plurality of sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, the method comprising the steps of:
(a). providing a fire signal to nozzles at a first and nth position m each set of nozzles;
(b). providing a fire signal to the next inward pair of nozzles in each set;
(c). in the event n is an even number, repeating step (b) until all of the nozzles in each set has been fired; and (d). in the event n is an odd number, repeating step (b) until all of the nozzles but a central nozzle in each set have been fired, and then firing the central nozzle.

1097. A printhead module according to claim 1083, having been manufactured in accordance with a method of manufacturing a plurality of printhead modules, at least some of which are capable of being combined in pairs to form bilithic pagewidth printheads, the method comprising the step of laying out each of the plurality of printhead modules on a wafer substrate, wherein at least one of the printhead modules is right-handed and at least another is left-handed.

1098. A printhead module according to claim 1083, including:

at least one row of print nozzles;
at least two shift registers for shifting in dot data supplied from a data source to each of the at least one rows, wherein each print nozzle obtains dot data to be fired from an element of one of the shift registers.

1099. A printhead module according to claim 1083, installed in a printer comprising:
a printhead comprising at least the first elongate printhead module, the at least one printhead module including at least one row of print nozzles for expelling ink; and at least first and second printer controllers configured to receive print data and process the print data to output dot data to the printhead, wherein the fust and second printer controllers are connected to a common input of the printhead.

1100. A printhead module according to claim 1083, installed in a printer comprising:
a printhead comprising fust and second elongate printhead modules, the printhead modules being parallel to each other and being disposed end to end on either side of a join region;
at least first and second printer controllers configured to receive print data and process the print data to output dot data to the printhead, wherein the first printer controller outputs dot data only to the first printhead module and the second printer controller outputs dot data only to the second printhead module, wherein the printhead modules are configured such that no dot data passes between them.

1101. A printhead module according to claim 1083, installed in a printer comprising:
a printhead comprising first and second elongate printhead modules, the printhead modules being parallel to each other and being disposed end to end on either side of a join region, wherein the first printhead module is longer than the second printhead module;
at least first and second printer controllers configured to receive print data and process the print data to output dot data to the printhead, wherein: the first printer controller outputs dot data to both the first printhead module and the second printhead module; and the second printer controller outputs dot data only to the second printhead module.

1102. A printhead module according to claim 1083, installed in a printer comprising:
a printhead comprising first and second elongate printhead modules, the printhead modules being parallel to each other and being disposed end to end on either side of a join region, wherein the first printhead module is longer than the second printhead module;
at least first and second printer controllers configured to receive print data and process the print data to output dot data for the printhead, wherein: the fust printer controller outputs dot data to both the first printhead module and the second controller; and the second printer controller outputs dot data to the second printhead module, wherein the dot data output by the second printer controller includes dot data it generates and at least some of the dot data received from the first printer controller.

1103. A printhead module according to claim 1083, in communication with a printer controller for supplying dot data to at least one printhead module and at least partially compensating for errors in ink dot placement by at least one of a plurality of nozzles on the printhead module due to erroneous rotational displacement of the printhead module relative to a carrier, the printer being configured to:
access a correction factor associated with the at least one printhead module;
determine an order in which at least some of the dot data is supplied to at least one of the at least one printhead modules, the order being determined at least partly on the basis of the correction factor, thereby to at least partially compensate for the rotational displacement; and supply the dot data to the printhead module.

1104. A printhead module according to claim 1083, in communication with a printer controller for supplying dot data to a printhead module having a plurality of nozzles for expelling ink, the printhead module including a plurality of thermal sensors, each of the thermal sensors being configured to respond to a temperature at or adjacent at least one of the nozzles, the printer controller being configured to modify operation of at least some of the nozzles in response to the temperature rising above a first threshold.

1105. A printhead module according to claim 1083, in communication with a printer controller for controlling a head comprising at least one monolithic printhead module, the at least one printhead module having a plurality of rows of nozzles configured to extend, in use, across at least part of a printable pagewidth of the printhead, the nozzles in each row being grouped into at least first and second fire groups, the printhead module being configured to sequentially fire, for each row, the nozzles of each fire group, such that each nozzle in the sequence from each fire group is fired simultaneously with respective corresponding nozzles in the sequence in the other fire groups, wherein the nozzles are fired row by row such that the nozzles of each row are all fired before the nozzles of each subsequent row, wherein the printer controller is configured to provide one or more control signals that control the order of firing of the nozzles.

1106. A printhead module according to claim 1083, in communication with a printer controller for outputting to a printhead module:
dot data to be printed with at least two different inks; and control data for controlling printing of the dot data;
the printer controller including at least one communication output, each or the communication output being configured to output at least some of the control data and at least some of the dot data for the at least two inks.

1107. A printhead module according to claim 1083, including at least one row of printhead nozzles, at least one row including at least one displaced row portion, the displacement of the row portion including a component in a direction normal to that of a pagewidth to be printed.

1108. A printhead module according to claim 1083, in communication with a printer controller for supplying print data to at least one printhead module capable of printing a maximum of n of channels of print data, the at least one printhead module being configurable into:
a first mode, in which the printhead module is configured to receive data for a first number of the channels; and a second mode, in which the printhead module is configured to receive print data for a second number of the channels, wherein the first number is greater than the second number;
wherein the printer controller is selectively configurable to supply dot data for the first and second modes.

1109. A printhead module according to claim 1083, in communication with a printer controller for supplying data to a printhead comprising a plurality of printhead modules, the printhead being wider than a reticle step used in forming the modules, the printhead comprising at least two types of the modules, wherein each type is determined by its geometric shape in plan.

1110. A printhead module according to claim 1083, used in conjunction with a printer controller for supplying one or more control signals to a printhead module, the printhead module including at least one row that comprises a plurality of sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, such that:
(a). a fire signal is provided to nozzles at a first and nth position in each set of nozzles;
(b). a fire signal is provided to the next inward pair of nozzles in each set;
(c). in the event n is an even number, step (b) is repeated until all of the nozzles in each set has been fired;
and (d), in the event n is an odd number, step (b) is repeated until all of the nozzles but a central nozzle in each set have been fired, and then the central nozzle is fired.

1111. A printhead module according to claim 1083, used in conjunction with a printer controller for supplying one or more control signals to a printhead module, the printhead module including at least one row that comprises a plurality of adjacent sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, the method comprising providing, for each set of nozzles, a fire signal in accordance with the sequence: [nozzle position 1, nozzle position n, nozzle position 2, nozzle position (n-1), ... , nozzle position x], wherein nozzle position x is at or adjacent the centre of the set of nozzles.

1112. A printhead module according to claim 1083, in communication with a printer controller for supplying dot data to a printhead module comprising at least first and second rows configured to print ink of a similar type or color, at least some nozzles in the first row being aligned with respective corresponding nozzles in the second row in a direction of intended media travel relative to the printhead, the printhead module being configurable such that the nozzles in the first and second pairs of rows are fired such that some dots output to print media are printed to by nozzles from the first pair of rows and at least some other dots output to print media are printed to by nozzles from the second pair of rows, the printer controller being configurable to supply dot data to the printhead module for printing.

1113. A printhead module according to claim 1083, in communication with a printer controller for supplying dot data to at least one printhead module, the at least one printhead module comprising a plurality of rows, each of the rows comprising a plurality of nozzles for ejecting ink, wherein the printhead module includes at least first and second rows configured to print ink of a similar type or color, the printer controller being configured to supply the dot data to the at least one printhead module such that, in the event a nozzle in the first row is faulty, a corresponding nozzle in the second row prints an ink dot at a position on print media at or adjacent a position where the faulty nozzle would otherwise have printed it.

1114. A printhead module according to claim 1083, in communication with a printer controller for receiving first data and manipulating the first data to produce dot data to be printed, the print controller including at least two serial outputs for supplying the dot data to at least one printhead.

1115. A printhead module according to claim 1083, including:
at least one row of print nozzles;
at least first and second shift registers for shifting in dot data supplied from a data source, wherein each shift register feeds dot data to a group of nozzles, and wherein each of the groups of the nozzles is interleaved with at least one of the other groups of the nozzles.

1116. A printhead module according to claim 1083 being capable of printing a maximum of n of channels of print data, the printhead being configurable into:
a first mode, in which the printhead is configured to receive print data for a first number of the channels; and a second mode, in which the printhead is configured to receive print data for a second number of the channels, wherein the first number is greater than the second number.

1117. A printhead comprising a plurality of printhead modules according to claim 1083, the printhead being wider than a reticle step used in forming the modules, the printhead comprising at least two types of the modules, wherein each type is determined by its geometric shape in plan.

1118. A printhead module according to claim 1083, including at least one row that comprises a plurality of adjacent sets of n adjacent nozzles, each of the nozzles being configured to expel the ink in response to a fire signal, the printhead being configured to output ink from nozzles at a first and nth position in each set of nozzles, and then each next inward pair of nozzles in each set, until:
in the event n is an even number, all of the nozzles in each set has been fired; and in the event n is an odd number, all of the nozzles but a central nozzle in each set have been fired, and then to fire the central nozzle.

1119. A printhead module according to claim 1083, for receiving dot data to be printed using at least two different inks and control data for controlling printing of the dot data, the printhead module including a communication input for receiving the dot data for the at least two colors and the control data.

1120. A printhead module according to claim 1083, including at least one row of printhead nozzles, at least one row including at least one displaced row portion, the displacement of the row portion including a component in a direction normal to that of a pagewidth to be printed.

1121. A printhead module according to claim 1083, having a plurality of rows of nozzles configured to extend, in use, across at least part of a printable pagewidth, the nozzles in each row being grouped into at least first and second fire groups, the printhead module being configured to sequentially fire, for each row, the nozzles of each fire group, such that each nozzle in the sequence from each fire group is fired simultaneously with respective corresponding nozzles in the sequence in the other fire groups, wherein the nozzles are fired row by row such that the nozzles of each row are all fired before the nozzles of each subsequent row.

1122. A printhead module according to claim 1083, comprising at least first and second rows configured to print ink of a similar type or color, at least some nozzles in the first row being aligned with respective corresponding nozzles in the second row in a direction of intended media travel relative to the printhead, the printhead module being configurable such that the nozzles in the first and second pairs of rows are fired such that some dots output to print media are printed to by nozzles from the first pair of rows and at least some other dots output to print media are printed to by nozzles from the second pair of rows.

1123. A printhead module according to claim 1083, in communication with a printer controller for providing data to a printhead module that includes:
at least one row of print nozzles;
at least first and second shift registers for shifting in dot data supplied from a data source, wherein each shift register feeds dot data to a group of nozzles, and wherein each of the groups of the nozzles is interleaved with at least one of the other groups of the nozzles.

1124. A printhead module according to claim 1083, having a plurality of nozzles for expelling ink, the printhead module including a plurality of thermal sensors, each of the thermal sensors being configured to respond to a temperature at or adjacent at least one of the nozzles, the printhead module being configured to modify operation of the nozzles in response to the temperature rising above a first threshold.

1125. A printhead module according to claim 1083, comprising a plurality of rows, each of the rows comprising a plurality of nozzles for ejecting ink, wherein the printhead module includes at least first and second rows configured to print ink of a similar type or color, and being configured such that, in the event a nozzle in the first row is faulty, a corresponding nozzle in the second row prints an ink dot at a position on print media at or adjacent a position where the faulty nozzle would otherwise have printed it.

1126. A printhead module according to claim 1083, comprising a plurality of the rows, the printhead module being configured to fire each nozzle in each row simultaneously with the nozzle or nozzles at the same position in the other rows.

1127. A printhead module according to claim 1083, including a plurality of pairs of the rows, each pair of rows including an odd row and an even row, the odd and even rows in each pair being offset from each other in both x and y directions relative to an intended direction of print media movement relative to the printhead, the printhead module being configured to cause firing of at least a plurality of the odd rows prior to firing any of the even rows, or vice versa.

1128. A printhead module according to claim 1127, wherein all the odd rows are fired before any of the even rows are fired, or vice versa.

1129. A printhead module according to claim 1127, wherein all the odd rows, or the even rows, or both, are fired in a predetermined order.

1130. A printhead module according to claim 1129, configurable such that the predetermined order is selectable from a plurality of predetermined available orders.

1131. A printhead module according to claim 1127, wherein the predetermined order is sequential.

1132. A printhead module according to claim 1131, configurable such that the predetermined order can commence at any of a plurality of the rows.

1133. A printhead module including at least one row that comprises a plurality of adjacent sets of n adjacent nozzles, each of the nozzles being configured to expel the ink in response to a fire signal, the printhead being configured to output ink from nozzles at a first and nth position in each set of nozzles, and then each next inward pair of nozzles in each set, until:
in the event n is an even number, all of the nozzles in each set has been fired; and in the event n is an odd number, all of the nozzles but a central nozzle in each set have been fired, and then to fire the central nozzle.

1134. A printhead module according to claim 1133, wherein the printhead module includes a plurality of the rows of nozzles, the printhead module being configured to fire all the nozzles on each row prior to firing any nozzles from a subsequent row.

1135. A printhead module according to claim 1134, wherein the rows are disposed in pairs.

1136. A printhead module according to claim 1135, wherein the rows in each pair of rows are offset relative to each other.

1137. A printhead module according to claim 1136, wherein each pair of rows is configured to print the same color ink.

1138. A printhead module according to claim 1137, wherein each pair of rows is connected to a common ink source.

1139. A printhead module according to claim 1133, wherein the sets of nozzles are adjacent each other.

1140. A printhead module according to claim 1133, wherein the sets of nozzles are separated by an intermediate nozzle, the intermediate nozzle being fired either prior to the nozzle at position 1 in each set, or following the nozzle at position n.

1141. A printhead module according to claim 1133, configured to receive dot data to which a method of at least partially compensating for errors in ink dot placement by at least one of a plurality of nozzles due to erroneous rotational displacement of a printhead module relative to a carrier has been applied, the nozzles being disposed on the printhead module, the method comprising the steps of:
determining the rotational displacement;
determining at least one correction factor that at least partially compensates for the ink dot displacement; and using the correction factor to alter the output of the ink dots to at least partially compensate for the rotational displacement.

1142. A printhead module according to claim 1133, configured to receive dot data to which a method of expelling ink has been applied, the method being applied to a printhead module including at least one row that comprises a plurality of adjacent sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, the method comprising providing, for each set of nozzles, a fire signal in accordance with the sequence: [nozzle position 1, nozzle position n, nozzle position 2, nozzle position (n-1), ... , nozzle position x], wherein nozzle position x is at or adjacent the centre of the set of nozzles.

1143. A printhead module according to claim 1133, configured to receive dot data to which a method of expelling ink has been applied, the method being applied to a printhead module including at least one row that comprises a plurality of sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, the method comprising the steps of:
(a). providing a fire signal to nozzles at a first and nth position in each set of nozzles;
(b). providing a fire signal to the next inward pair of nozzles in each set;
(c). in the event n is an even number, repeating step (b) until all of the nozzles in each set has been fired; and (d). in the event n is an odd number, repeating step (b) until all of the nozzles but a central nozzle in each set have been fired, and then firing the central nozzle.

1144. A printhead module according to claim 1133, having been manufactured in accordance with a method of manufacturing a plurality of printhead modules, at least some of which are capable of being combined in pairs to form bilithic pagewidth printheads, the method comprising the step of laying out each of the plurality of printhead modules on a wafer substrate, wherein at least one of the printhead modules is right-handed and at least another is left-handed.

1145. A printhead module according to claim 1133, including:
at least one row of print nozzles;
at least two shift registers for shifting in dot data supplied from a data source to each of the at least one rows, wherein each print nozzle obtains dot data to be fired from an element of one of the shift registers.

1146. A printhead module according to claim 1133, installed in a printer comprising:
a printhead comprising at least the first elongate printhead module, the at least one printhead module including at least one row of print nozzles for expelling ink; and at least first and second printer controllers configured to receive print data and process the print data to output dot data to the printhead, wherein the first and second printer controllers are connected to a common input of the printhead.

1147. A printhead module according to claim 1133, installed in a printer comprising:
a printhead comprising first and second elongate printhead modules, the printhead modules being parallel to each other and being disposed end to end on either side of a join region;
at least first and second printer controllers configured to receive print data and process the print data to output dot data to the printhead, wherein the first printer controller outputs dot data only to the first printhead module and the second printer controller outputs dot data only to the second printhead module, wherein the printhead modules are configured such that no dot data passes between them.

1148. A printhead module according to claim 1133, installed in a printer comprising:
a printhead comprising first and second elongate printhead modules, the printhead modules being parallel to each other and being disposed end to end on either side of a join region, wherein the first printhead module is longer than the second printhead module;
at least first and second printer controllers configured to receive print data and process the print data to output dot data to the printhead, wherein: the first printer controller outputs dot data to both the first printhead module and the second printhead module; and the second printer controller outputs dot data only to the second printhead module.

1149. A printhead module according to claim 1133, installed in a printer comprising:
a printhead comprising first and second elongate printhead modules, the printhead modules being parallel to each other and being disposed end to end on either side of a join region, wherein the first printhead module is longer than the second printhead module;
at least first and second printer controllers configured to receive print data and process the print data to output dot data for the printhead, wherein: the first printer controller outputs dot data to both the first printhead module and the second controller; and the second printer controller outputs dot data to the second printhead module, wherein the dot data output by the second printer controller includes dot data it generates and at least some of the dot data received from the fust printer controller.

1150. A printhead module according to claim 1133, in communication with a printer controller for supplying dot data to at least one printhead module and at least partially compensating for errors in ink dot placement by at least one of a plurality of nozzles on the printhead module due to erroneous rotational displacement of the printhead module relative to a carrier, the printer being configured to:
access a correction factor associated with the at least one printhead module;
determine an order in which at least some of the dot data is supplied to at least one of the at least one printhead modules, the order being determined at least partly on the basis of the correction factor, thereby to at least partially compensate for the rotational displacement; and supply the dot data to the printhead module.

1151. A printhead module according to claim 1133, in communication with a printer controller for supplying dot data to a printhead module having a plurality of nozzles for expelling ink, the printhead module including a plurality of thermal sensors, each of the thermal sensors being configured to respond to a temperature at or adjacent at least one of the nozzles, the printer controller being configured to modify operation of at least some of the nozzles in response to the temperature rising above a first threshold.

1152. A printhead module according to claim 1133, in communication with a printer controller for controlling a printhead comprising at least one monolithic printhead module, the at least one printhead module having a plurality of rows of nozzles configured to extend, in use, across at least part of a printable pagewidth of the printhead, the nozzles in each row being grouped into at least first and second fire groups, the printhead module being configured to sequentially fire, for each row, the nozzles of each fire group, such that each nozzle in the sequence from each fire group is fired simultaneously with respective corresponding nozzles in the sequence in the other fire groups, wherein the nozzles are fired row by row such that the nozzles of each row are all fired before the nozzles of each subsequent row, wherein the printer controller is configured to provide one or more control signals that control the order of firing of the nozzles.

1153. A printhead module according to claim 1133, in communication with a printer controller for outputting to a printhead module:
dot data to be printed with at least two different inks; and control data for controlling printing of the dot data;
the printer controller including at least one communication output, each or the communication output being configured to output at least some of the control data and at least some of the dot data for the at least two inks.

1154. A printhead module according to claim 1133, including at least one row of printhead nozzles, at least one row including at least one displaced row portion, the displacement of the row portion including a component in a direction normal to that of a pagewidth to be printed.

1155. A printhead module according to claim 1133, in communication with a printer controller for supplying print data to at least one printhead module capable of printing a maximum of n of channels of print data, the at least one printhead module being configurable into:
a first mode, in which the printhead module is configured to receive data for a first number of the channels; and a second mode, in which the printhead module is configured to receive print data for a second number of the channels, wherein the first number is greater than the second number, wherein the printer controller is selectively configurable to supply dot data for the first and second modes.

1156. A printhead module according to claim 1133, in communication with a printer controller for supplying data to a printhead comprising a plurality of printhead modules, the printhead being wider than a reticle step used in forming the modules, the printhead comprising at least two types of the modules, wherein each type is determined by its geometric shape in plan.

1157. A printhead module according to claim 1133, used in conjunction with a printer controller for supplying one or more control signals to a printhead module, the printhead module including at least one row that comprises a plurality of sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, such that (a). a fire signal is provided to nozzles at a first and nth position in each set of nozzles;

(b). a fire signal is provided to the next inward pair of nozzles in each set;
(c). in the event n is an even number, step (b) is repeated until all of the nozzles in each set has been fired;
and (d). in the event n is an odd number, step (b) is repeated until all of the nozzles but a central nozzle in each set have been fired, and then the central nozzle is fired

1158. A printhead module according to claim 1133, used in conjunction with a printer controller for supplying one or more control signals to a printhead module, the printhead module including at least one row that comprises a plurality of adjacent sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, the method comprising providing, for each set of nozzles, a fire signal in accordance with the sequence: [nozzle position 1, nozzle position n, nozzle position 2, nozzle position (n-1), ... , nozzle position x], wherein nozzle position x is at or adjacent the centre of the set of nozzles.

1159. A printhead module according to claim 1133, in communication with a printer controller for supplying dot data to a printhead module comprising at least first and second rows configured to print ink of a similar type or color, at least some nozzles in the first row being aligned with respective corresponding nozzles in the second row in a direction of intended media travel relative to the printhead, the printhead module being configurable such that the nozzles in the first and second pairs of rows are fired such that some dots output to print media are printed to by nozzles from the first pair of rows and at least some other dots output to print media are printed to by nozzles from the second pair of rows, the printer controller being configurable to supply dot data to the printhead module for printing.

1160. A printhead module according to claim 1133, in communication with a printer controller for supplying dot data to at least one printhead module, the at least one printhead module comprising a plurality of rows, each of the rows comprising a plurality of nozzles for ejecting ink, wherein the printhead module includes at least first and second rows configured to print ink of a similar type or color, the printer controller being configured to supply the dot data to the at least one printhead module such that, in the event a nozzle in the first row is faulty, a corresponding nozzle in the second row prints an ink dot at a position on print media at or adjacent a position where the faulty nozzle would otherwise have printed it.

1161. A printhead module according to claim 1133, in communication with a printer controller for receiving first data and manipulating the first data to produce dot data to be printed, the print controller including at least two serial outputs for supplying the dot data to at least one printhead.

1162. A printhead module according to claim 1133, including:
at least one row of print nozzles;

at least first and second shift registers for shifting in dot data supplied from a data source, wherein each shift register feeds dot data to a group of nozzles, and wherein each of the groups of the nozzles is interleaved with at least one of the other groups of the nozzles.

1163. A printhead module according to claim 1133 being capable of printing a maximum of n of channels of print data, the printhead being configurable into:
a fust mode, in which the printhead is configured to receive print data for a first number of the channels; and a second mode, in which the printhead is configured to receive print data for a second number of the channels, wherein the first number is greater than the second number.

1164. A printhead comprising a plurality of printhead modules according to claim 1133, the printhead being wider than a reticle step used in forming the modules, the printhead comprising at least two types of the modules, wherein each type is determined by its geometric shape in plan.

1165. A printhead module according to claim 1133, including at least one row that comprises a plurality of sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, such that, for each set of nozzles, a fire signal is provided in accordance with the sequence: [nozzle position 1, nozzle position n, nozzle position 2, nozzle position (n-1), ... , nozzle position x], wherein nozzle position x is at or adjacent the centre of the set of nozzles.

1166. A printhead module according to claim 1133, for receiving dot data to be printed using at least two different inks and control data for controlling printing of the dot data, the printhead module including a communication input for receiving the dot data for the at least two colors and the control data.

1167. A printhead module according to claim 1133, including at least one row of printhead nozzles, at least one row including at least one displaced row portion, the displacement of the row portion including a component in a direction normal to that of a pagewidth to be printed.

1168. A printhead module according to claim 1133, having a plurality of rows of nozzles configured to extend, in use, across at least part of a printable pagewidth, the nozzles in each row being grouped into at least first and second fire groups, the printhead module being configured to sequentially fire, for each row, the nozzles of each fire group, such that each nozzle in the sequence from each fire group is fired simultaneously with respective corresponding nozzles in the sequence in the other fire groups, wherein the nozzles are fired row by row such that the nozzles of each row are all fired before the nozzles of each subsequent row.

1169. A printhead module according to claim 1133, comprising at least first and second rows configured to print ink of a similar type or color, at least some nozzles in the first row being aligned with respective corresponding nozzles in the second row in a direction of intended media travel relative to the printhead, the printhead module being configurable such that the nozzles in the first and second pairs of rows are fired such that some dots output to print media ar.e printed to by nozzles from the first pair of rows and at least some other dots output to print media are printed to by nozzles from the second pair of rows.

1170. A printhead module according to claim 1133, in communication with a printer controller for providing data to a printhead module that includes:
at least one row of print nozzles;
at least first and second shift registers for shifting in dot data supplied from a data source, wherein each shift register feeds dot data to a group of nozzles, and wherein each of the groups of the nozzles is interleaved with at least one of the other groups of the nozzles.

1171. A printhead module according to claim 1133, having a plurality of nozzles for expelling ink, the printhead module including a plurality of thermal sensors, each of the thermal sensors being configured to respond to a temperature at or adjacent at least one of the nozzles, the printhead module being configured to modify operation of the nozzles in response to the temperature rising above a first threshold.

1172. A printhead module according to claim 1133, comprising a plurality of rows, each of the rows comprising a plurality of nozzles for ejecting ink, wherein the printhead module includes at least first and second rows configured to print ink of a similar type or color, and being configured such that, in the event a nozzle in the first row is faulty, a corresponding nozzle in the second row prints an ink dot at a position on print media at or adjacent a position where the faulty nozzle would otherwise have printed it.

1173. A printhead module according to claim 1133, comprising a plurality of the rows, the printhead module being configured to fire each nozzle in each row simultaneously with the nozzle or nozzles at the same position in the other rows.

1174. A printhead module according to claim 1133, including a plurality of pairs of the rows, each pair of rows including an odd row and an even row, the odd and even rows in each pair being offset from each other in both x and y directions relative to an intended direction of print media movement relative to the printhead, the printhead module being configured to cause firing of at least a plurality of the odd rows prior to firing any of the even rows, or vice versa.

1175. A printhead module according to claim 1174, wherein all the odd rows are fired before any of the even rows are fired, or vice versa.

1176. A printhead module according to claim 1174, wherein all the odd rows, or the even rows, or both, are fired in a predetermined order.

1177. A printhead module according to claim 1176, configurable such that the predetermined order is selectable from a plurality of predetermined available orders.

1178. A printhead module according to claim 1174, wherein the predetermined order is sequential.

1179. A printhead module according to claim 1178, configurable such that the predetermined order can commence at any of a plurality of the rows.

1180. A printhead module for receiving dot data to be printed using at least two different inks and control data for controlling printing of the dot data, the printhead module including a communication input for receiving the dot data for the at least two colors and the control data.

1181. A printhead module according to claim 1180, wherein the communication input is configured to receive the dot data and control data serially.

1182. A printhead module according to claim 1180, further including a plurality of the communication inputs.

1183. A printhead module according to claim 1181, further including a plurality of the communication inputs.

1184. A printhead comprising a plurality of printhead modules according to claim 1180, the printhead modules being disposed end to end for printing a width exceeding that of any of the individual printhead modules, the communications input of each of the printhead modules being connected to a common dot data and control data bus.

1185. A printhead according to claim 1184, wherein each module is configured to respond to dot data and control data on the bus only when it is intended for that module.

1186. A printhead module according to claim 1180, configured to receive dot data to which a method of at least partially compensating for errors in ink dot placement by at least one of a plurality of nozzles due to erroneous rotational displacement of a printhead module relative to a carrier has been applied, the nozzles being disposed on the printhead module, the method comprising the steps of:
determining the rotational displacement;
determining at least one correction factor that at least partially compensates for the ink dot displacement; and using the correction factor to alter the output of the ink dots to at least partially compensate for the rotational displacement.

1187. A printhead module according to claim 1180, configured to receive dot data to which a method of expelling ink has been applied, the method being applied to a printhead module including at least one row that comprises a plurality of adjacent sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, the method comprising providing, for each set of nozzles, a fire signal in accordance with the sequence: [nozzle position 1, nozzle position n, nozzle position 2, nozzle position (n-1), ... , nozzle position x], wherein nozzle position x is at or adjacent the centre of the set of nozzles.

1188. A printhead module according to claim 1180, configured to receive dot data to which a method of expelling ink has been applied, the method being applied to a printhead module including at least one row that comprises a plurality of sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, the method comprising the steps of:
(a). providing a fire signal to nozzles at a first and nth position in each set of nozzles;
(b). providing a fire signal to the next inward pair of nozzles in each set;
(c). in the event n is an even number, repeating step (b) until all of the nozzles in each set has been fired; and (d). in the event n is an odd number, repeating step (b) until all of the nozzles but a central nozzle in each set have been fired, and then firing the central nozzle.

1189. A printhead module according to claim 1180, having been manufactured in accordance with a method of manufacturing a plurality of printhead modules, at least some of which are capable of being combined in pairs to form bilithic pagewidth printheads, the method comprising the step of laying out each of the plurality of printhead modules on a wafer substrate, wherein at least one of the printhead modules is right-handed and at least another is left-handed.

1190. A printhead module according to claim 1180, including:
at least one row of print nozzles;
at least two shift registers for shifting in dot data supplied from a data source to each of the at least one rows, wherein each print nozzle obtains dot data to be fired from an element of one of the shift registers.

1191. A printhead module according to claim 1180, installed in a printer comprising:
a printhead comprising at least the first elongate printhead module, the at least one printhead module including at least one row of print nozzles for expelling ink; and at least first and second printer controllers configured to receive print data and process the print data to output dot data to the printhead, wherein the first and second printer controllers are connected to a common input of the printhead.

1192. A printhead module according to claim 1180, installed in a printer comprising:
a printhead comprising first and second elongate printhead modules, the printhead modules being parallel to each other and being disposed end to end on either side of a join region;
at least first and second printer controllers configured to receive print data and process the print data to output dot data to the printhead, wherein the first printer controller outputs dot data only to the first printhead module and the second printer controller outputs dot data only to the second printhead module, wherein the printhead modules are configured such that no dot data passes between them.

1193. A printhead module according to claim 1180, installed in a printer comprising:
a printhead comprising first and second elongate printhead modules, the printhead modules being parallel to each other and being disposed end to end on either side of a join region, wherein the first printhead module is longer than the second printhead module;
at least first and second printer controllers configured to receive print data and process the print data to output dot data to the printhead, wherein: the first printer controller outputs dot data to both the first printhead module and the second printhead module; and the second printer controller outputs dot data only to the second printhead module.

1194. A printhead module according to claim 1180, installed in a printer comprising:
a printhead comprising first and second elongate printhead modules, the printhead modules being parallel to each other and being disposed end to end on either side of a join region, wherein the first printhead module is longer than the second printhead module;
at least first and second printer controllers configured to receive print data and process the print data to output dot data for the printhead, wherein: the fust printer controller outputs dot data to both the first printhead module and the second controller, and the second printer controller outputs dot data to the second printhead module, wherein the dot data output by the second printer controller includes dot data it generates and at least some of the dot data received from the first printer controller.

1195. A printhead module according to claim 1180, in communication with a printer controller for supplying dot data to at least one printhead module and at least partially compensating for errors in ink dot placement by at least one of a plurality of nozzles on the printhead module due to erroneous rotational displacement of the printhead module relative to a carrier, the printer being configured to:
access a correction factor associated with the at least one printhead module;
determine an order in which at least some of the dot data is supplied to at least one of the at least one printhead modules, the order being determined at least partly on the basis of the correction factor, thereby to at least partially compensate for the rotational displacement; and supply the dot data to the printhead module.

1196. A printhead module according to claim 1180, in communication with a printer controller for supplying dot data to a printhead module having a plurality of nozzles for expelling ink, the printhead module including a plurality of thermal sensors, each of the thermal sensors being configured to respond to a temperature at or adjacent at least one of the nozzles, the printer controller being configured to modify operation of at least some of the nozzles in response to the temperature rising above a first threshold.

1197. A printhead module according to claim 1180, in communication with a printer controller for controlling a printhead comprising at least one monolithic printhead module, the at least one printhead module having a plurality of rows of nozzles configured to extend, in use, across at least part of a printable pagewidth of the printhead, the nozzles in each row being grouped into at least first and second fire groups, the printhead module being configured to sequentially fire, for each row, the nozzles of each fire group, such that each nozzle in the sequence from each fire group is fired simultaneously with respective corresponding nozzles in the sequence in the other fire groups, wherein the nozzles are fired row by row such that the nozzles of each row are all fired before the nozzles of each subsequent row, wherein the printer controller is configured to provide one or more control signals that control the order of firing of the nozzles.

1198. A printhead module according to claim 1180, in communication with a printer controller for outputting to a printhead module:
dot data to be printed with at least two different inks; and control data for controlling printing of the dot data;
the printer controller including at least one communication output, each or the communication output being configured to output at least some of the control data and at least some of the dot data for the at least two inks.

1199. A printhead module according to claim 1180, including at least one row of printhead nozzles, at least one row including at least one displaced row portion, the displacement of the row portion including a component in a direction normal to that of a pagewidth to be printed.

1200. A printhead module according to claim 1180, in communication with a printer controller for supplying print data to at least one printhead module capable of printing a maximum of n of channels of print data, the at least one printhead module being configurable into:
a first mode, in which the printhead module is configured to receive data for a first number of the channels; and a second mode, in which the printhead module is configured to receive print data for a second number of the channels, wherein the first number is greater than the second number;
wherein the printer controller is selectively configurable to supply dot data for the first and second modes.

1201. A printhead module according to claim 1180, in communication with a printer controller for supplying data to a printhead comprising a plurality of printhead modules, the printhead being wider than a reticle step used in forming the modules, the printhead comprising at least two types of the modules, wherein each type is determined by its geometric shape in plan.

1202. A printhead module according to claim 1180, used in conjunction with a printer controller for supplying one or more control signals to a printhead module, the printhead module including at least one row that comprises a plurality of sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, such that:
(a). a fire signal is provided to nozzles at a first and nth position in each set of nozzles;
(b). a fire signal is provided to the next inward pair of nozzles in each set;
(c). in the event n is an even number, step (b) is repeated until all of the nozzles in each set has been fired;
and (d). in the event n is an odd number, step (b) is repeated until all of the nozzles but a central nozzle in each set have been fired, and then the central nozzle is fired.

1203. A printhead module according to claim 1180, used in conjunction with a printer controller for supplying one or more control signals to a printhead module, the printhead module including at least one row that comprises a plurality of adjacent sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, the method comprising providing, for each set of nozzles, a fire signal in accordance with the sequence: [nozzle position 1, nozzle position n, nozzle position 2, nozzle position (n-1), ... , nozzle position x], wherein nozzle position x is at or adjacent the centre of the set of nozzles.

1204. A printhead module according to claim 1180, in communication with a printer controller for supplying dot data to a printhead module comprising at least first and second rows configured to print ink of a similar type or color, at least some nozzles in the first row being aligned with respective corresponding nozzles in the second row in a direction of intended media travel relative to the printhead, the printhead module being configurable such that the nozzles in the first and second pairs of rows are fired such that some dots output to print media are printed to by nozzles from the first pair of rows and at least some other dots output to print media are printed to by nozzles from the second pair of rows, the printer controller being configurable to supply dot data to the printhead module for printing.

1205. A printhead module according to claim 1180, in communication with a printer controller for supplying dot data to at least one printhead module, the at least one printhead module comprising a plurality of rows, each of the rows comprising a plurality of nozzles for ejecting ink, wherein the printhead module includes at least first and second rows configured to print ink of a siniilar type or color, the printer controller being configured to supply the dot data to the at least one printhead module such that, in the event a nozzle in the first row is faulty, a corresponding nozzle in the second row prints an ink dot at a position on print media at or adjacent a position where the faulty nozzle would otherwise have printed it.

1206. A printhead module according to claim 1180, in communication with a printer controller for receiving first data and manipulating the first data to produce dot data to be printed, the print controller including at least two serial outputs for supplying the dot data to at least one printhead.

1207. A printhead module according to claim 1180, including:
at least one row of print nozzles;
at least first and second shift registers for shifting in dot data supplied from a data source, wherein each shift register feeds dot data to a group of nozzles, and wherein each of the groups of the nozzles is interleaved with at least one of the other groups of the nozzles.

1208. A printhead module according to claim 1180 being capable of printing a maximum of n of channels of print data, the printhead being configurable into:
a first mode, in which the printhead is configured to receive print data for a first number of the channels; and a second mode, in which the printhead is configured to receive print data for a second number of the channels, wherein the first number is greater than the second number.

1209. A printhead comprising a plurality of printhead modules according to claim 1180, the printhead being wider than a reticle step used in forming the modules, the printhead comprising at least two types of the modules, wherein each type is determined by its geometric shape in plan.

1210. A printhead module according to claim 1180, including at least one row that comprises a plurality of sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, such that, for each set of nozzles, a fire signal is provided in accordance with the sequence: [nozzle position 1, nozzle position n, nozzle position 2, nozzle position (n-1), ... , nozzle position x], wherein nozzle position x is at or adjacent the centre of the set of nozzles.

1211. A printhead module according to claim 1180, including at least one row that comprises a plurality of adjacent sets of n adjacent nozzles, each of the nozzles being configured to expel the ink in response to a fire signal, the printhead being configured to output ink from nozzles at a first and nth position in each set of nozzles, and then each next inward pair of nozzles in each set, until:
in the event n is an even number, all of the nozzles in each set has been fired; and in the event n is an odd number, all of the nozzles but a central nozzle in each set have been fired, and then to fire the central nozzle.

1212. A printhead module according to claim 1180, including at least one row of printhead nozzles, at least one row including at least one displaced row portion, the displacement of the row portion including a component in a direction normal to that of a pagewidth to be printed.

1213. A printhead module according to claim 1180, having a plurality of rows of nozzles configured to extend, in use, across at least part of a printable pagewidth, the nozzles in each row being grouped into at least first and second fire groups, the printhead module being configured to sequentially fire, for each row, the nozzles of each fire group, such that each nozzle in the sequence from each fire group is fired simultaneously with respective corresponding nozzles in the sequence in the other fire groups, wherein the nozzles are fired row by row such that the nozzles of each row are all fired before the nozzles of each subsequent row.

1214. A printhead module according to claim 1180, comprising at least first and second rows configured to print ink of a similar type or color, at least some nozzles in the fust row being aligned with respective corresponding nozzles in the second row in a direction of intended media travel relative to the printhead, the printhead module being configurable such that the nozzles in the first and second pairs of rows are fired such that some dots output to print media are printed to by nozzles from the first pair of rows and at least some other dots output to print media are printed to by nozzles from the second pair of rows.

1215. A printhead module according to claim 1180, in communication with a printer controller for providing data to a printhead module that includes:
at least one row of print nozzles;
at least first and second shift registers for shifting in dot data supplied from a data source, wherein each shift register feeds dot data to a group of nozzles, and wherein each of the groups of the nozzles is interleaved with at least one of the other groups of the nozzles.

1216. A printhead module according to claim 1180, having a plurality of nozzles for expelling ink, the printhead module including a plurality of thermal sensors, each of the thermal sensors being configured to respond to a temperature at or adjacent at least one of the nozzles, the printhead module being configured to modify operation of the nozzles in response to the temperature rising above a first threshold.

1217. A printhead module according to claim 1180, comprising a plurality of rows, each of the rows comprising a plurality of nozzles for ejecting ink, wherein the printhead module includes at least first and second rows configured to print ink of a similar type or color, and being configured such that, in the event a nozzle in the first row is faulty, a corresponding nozzle in the second row prints an ink dot at a position on print media at or adjacent a position where the faulty nozzle would otherwise have printed it.

1218. A printhead module including at least one row of printhead nozzles, at least one row including at least one displaced row portion, the displacement of the row portion including a component in a direction normal to that of a pagewidth to be printed.

1219. A printhead module according to claim 1218, wherein the displaced row portion is disposed adjacent one end of the monolithic printhead module.

1220. A printhead module according to claim 1218, including a plurality of the rows, wherein each of at least a plurality of the rows includes one of the displaced row portions.

1221. A printhead module according to claim 1220, wherein the displaced row portions of at least some of the rows are different in length than the displaced row portions of at least some of the other rows.

1222. A printhead module according to claim 1221, wherein each of the rows has a displaced row portion, and the sizes of the respective displaced row portions increase from row to row in the direction normal to that of the pagewidth to be printed.

1223. A printhead module according to claim 1222, wherein the dropped rows together comprise a generally trapezoidal shape, in plan.

1224. A printhead module according to claim 1222, wherein the dropped rows together comprise a generally triangular shape, in plan.

1225. A printhead comprising a plurality of printhead modules, including at least one of the printhead modules according to claim 1218.

1226. A printhead comprising a plurality of printhead modules, including at least one the printhead modules according to claim 2, wherein the displaced row portion of at least one of the printhead modules is disposed adjacent another of the printhead modules.

1227. A printhead according to claim 1226, wherein the printhead modules are the same shape and configuration as each other, and are arranged end to end across the intended print width.

1228. A printhead according to claim 1225, the printhead being a pagewidth printhead.

1229. A printhead according to claim 1227, the printhead being a pagewidth printhead.

1230. A printhead module according to claim 1218, configured to receive dot data to which a method of at least partially compensating for errors in ink dot placement by at least one of a plurality of nozzles due to erroneous rotational displacement of a printhead module relative to a carrier has been applied, the nozzles being disposed on the printhead module, the method comprising the steps of:
determining the rotational displacement;
determining at least one correction factor that at least partially compensates for the ink dot displacement; and using the correction factor to alter the output of the ink dots to at least partially compensate for the rotational displacement.

1231. A printhead module according to claim 1218, configured to receive dot data to which a method of expelling ink has been applied, the method being applied to a printhead module including at least one row that comprises a plurality of adjacent sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, the method comprising providing, for each set of nozzles, a fire signal in accordance with the sequence: [nozzle position 1, nozzle position n, nozzle position 2, nozzle position (n-1), ... , nozzle position x], wherein nozzle position x is at or adjacent the centre of the set of nozzles.

1232. A printhead module according to claim 1218, configured to receive dot data to which a method of expelling ink has been applied, the method being applied to a printhead module including at least one row that comprises a plurality of sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, the method comprising the steps of:
(a). providing a fire signal to nozzles at a first and nth position in each set of nozzles;
(b). providing a fire signal to the next inward pair of nozzles in each set;
(c). in the event n is an even number, repeating step (b) until all of the nozzles in each set has been fired; and (d). in the event n is an odd number, repeating step (b) until all of the nozzles but a central nozzle in each set have been fired, and then firing the central nozzle.

1233. A printhead module according to claim 1218, having been manufactured in accordance with a method of manufacturing a plurality of printhead modules, at least some of which are capable of being combined in pairs to form bilithic pagewidth printheads, the method comprising the step of laying out each of the plurality of printhead modules on a wafer substrate, wherein at least one of the printhead modules is right-handed and at least another is left-handed.

1234. A printhead module according to claim 1218, including:
at least one row of print nozzles;
at least two shift registers for shifting in dot data supplied from a data source to each of the at least one rows, wherein each print nozzle obtains dot data to be fired from an element of one of the shift registers.

1235. A printhead module according to claim 1218, installed in a printer comprising:
a printhead comprising at least the first elongate printhead module, the at least one printhead module including at least one row of print nozzles for expelling ink; and at least first and second printer controllers configured to receive print data and process the print data to output dot data to the printhead, wherein the first and second printer controllers are connected to a common input of the printhead.

1236. A printhead module according to claim 1218, installed in a printer comprising:
a printhead comprising first and second elongate printhead modules, the printhead modules being parallel to each other and being disposed end to end on either side of a join region;
at least first and second printer controllers configured to receive print data and process the print data to output dot data to the printhead, wherein the first printer controller outputs dot data only to the first printhead module and the second printer controller outputs dot data only to the second printhead module, wherein the printhead modules are configured such that no dot data passes between them.

1237. A printhead module according to claim 1218, installed in a printer comprising:
a printhead comprising first and second elongate printhead modules, the printhead modules being parallel to each other and being disposed end to end on either side of a join region, wherein the first printhead module is longer than the second printhead module;
at least first and second printer controllers configured to receive print data and process the print data to output dot data to the printhead, wherein: the first printer controller outputs dot data to both the first printhead module and the second printhead module; and the second printer controller outputs dot data only to the second printhead module.

1238. A printhead module according to claim 1218, installed in a printer comprising:
a printhead comprising first and second elongate printhead modules, the printhead modules being parallel to each other and being disposed end to end on either side of a join region, wherein the first printhead module is longer than the second printhead module;
at least first and second printer controllers configured to receive print data and process the print data to output dot data for the printhead, wherein: the first printer controller outputs dot data to both the first printhead module and the second controller; and the second printer controller outputs dot data to the second printhead module, wherein the dot data output by the second printer controller includes dot data it generates and at least some of the dot data received from the first printer controller.

1239. A printhead module according to claim 1218, in communication with a printer controller for supplying dot data to at least one printhead module and at least partially compensating for errors in ink dot placement by at least one of a plurality of nozzles on the printhead module due to erroneous rotational displacement of the printhead module relative to a carrier, the printer being configured to:
access a correction factor associated with the at least one printhead module;
determine an order in which at least some of the dot data is supplied to at least one of the at least one printhead modules, the order being determined at least partly on the basis of the correction factor, thereby to at least partially compensate for the rotational displacement; and supply the dot data to the printhead module.

1240. A printhead module according to claim 1218, in communication with a printer controller for supplying dot data to a printhead module having a plurality of nozzles for expelling ink, the printhead module including a plurality of thermal sensors, each of the thermal sensors being configured to respond to a temperature at or adjacent at least one of the nozzles, the printer controller being configured to modify operation of at least some of the nozzles in response to the temperature rising above a first threshold.

1241. A printhead module according to claim 1218, in communication with a printer controller for controlling a printhead comprising at least one monolithic printhead module, the at least one printhead module having a plurality of rows of nozzles configured to extend, in use, across at least part of a printable pagewidth of the printhead, the nozzles in each row being grouped into at least first and second fire groups, the printhead module being configured to sequentially fire, for each row, the nozzles of each fire group, such that each nozzle in the sequence from each fire group is fired simultaneously with respective corresponding nozzles in the sequence in the other fire groups, wherein the nozzles are fired row by row such that the nozzles of each row are all fired before the nozzles of each subsequent row, wherein the printer controller is configured to provide one or more control signals that control the order of firing of the nozzles.

1242. A printhead module according to claim 1218, in communication with a printer controller for outputting to a printhead module:
dot data to be printed with at least two different inks; and control data for controlling printing of the dot data;
the printer controller including at least one communication output, each or the communication output being configured to output at least some of the control data and at least some of the dot data for the at least two inks.

1243. A printhead module according to claim 1218, including at least one row of printhead nozzles, at least one row including at least one displaced row portion, the displacement of the row portion including a component in a direction normal to that of a pagewidth to be printed.

1244. A printhead module according to claim 1218, in communication with a printer controller for supplying print data to at least one printhead module capable of printing a maximum of n of channels of print data, the at least one printhead module being configurable into:
a first mode, in which the printhead module is configured to receive data for a first number of the channels; and a second mode, in which the printhead module is configured to receive print data for a second number of the channels, wherein the first number is greater than the second number, wherein the printer controller is selectively configurable to supply dot data for the first and second modes.

1245. A printhead module according to claim 1218, in communication with a printer controller for supplying data to a printhead comprising a plurality of printhead modules, the printhead being wider than a reticle step used in forming the modules, the printhead comprising at least two types of the modules, wherein each type is determined by its geometric shape in plan.

1246. A printhead module according to claim 1218, used in conjunction with a printer controller for supplying one or more control signals to a printhead module, the printhead module including at least one row that comprises a plurality of sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, such that:
(a). a fire signal is provided to nozzles at a first and nth position in each set of nozzles;
(b). a fire signal is provided to the next inward pair of nozzles in each set;
(c). in the event n is an even number, step (b) is repeated until all of the nozzles in each set has been fired;
and (d). in the event n is an odd number, step (b) is repeated until all of the nozzles but a central nozzle in each set have been fLred, and then the central nozzle is fired.

1247. A printhead module according to claim 1218, used in conjunction with a printer controller for supplying one or more control signals to a printhead module, the printhead module including at least one row that comprises a plurality of adjacent sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, the method comprising providing, for each set of nozzles, a fire signal in accordance with the sequence: [nozzle position 1, nozzle position n, nozzle position 2, nozzle position (n-1), ... , nozzle position x], wherein nozzle position x is at or adjacent the centre of the set of nozzles.

1248. A printhead module according to claim 1218, in communication with a printer controller for supplying dot data to a printhead module comprising at least first and second rows configured to print ink of a similar type or color, at least some nozzles in the first row being aligned with respective corresponding nozzles in the second row in a direction of intended media travel relative to the printhead, the printhead module being configurable such that the nozzles in the first and second pairs of rows are fired such that some dots output to print media are printed to by nozzles from the first pair of rows and at least some other dots output to print media are printed to by nozzles from the second pair of rows, the printer controller being configurable to supply dot data to the printhead module for printing.

1249. A printhead module according to claim 1218, in communication with a printer controller for supplying dot data to at least one printhead module, the at least one printhead module comprising a plurality of rows, each of the rows comprising a plurality of nozzles for ejecting ink, wherein the printhead module includes at least first and second rows configured to print ink of a similar type or color, the printer controller being configured to supply the dot data to the at least one printhead module such that, in the event a nozzle in the first row is faulty, a corresponding nozzle in the second row prints an ink dot at a position on print media at or adjacent a position where the faulty nozzle would otherwise have printed it.

1250. A printhead module according to claim 1218, in communication with a printer controller for receiving first data and manipulating the first data to produce dot data to be printed, the print controller including at least two serial outputs for supplying the dot data to at least one printhead.

1251. A printhead module according to claim 1218, including:
at least one row of print nozzles;
at least first and second shift registers for shifting in dot data supplied from a data source, wherein each shift register feeds dot data to a group of nozzles, and wherein each of the groups of the nozzles is interleaved with at least one of the other groups of the nozzles.

1252. A printhead module according to claim 1218 being capable of printing a maximum of n of channels of print data, the printhead being configurable into:
a first mode, in which the printhead is configured to receive print data for a first number of the channels; and a second mode, in which the printhead is configured to receive print data for a second number of the channels, wherein the first number is greater than the second number.

1253. A printhead comprising a plurality of printhead modules according to claim 1218, the printhead being wider than a reticle step used in forming the modules, the printhead comprising at least two types of the modules, wherein each type is determined by its geometric shape in plan.

1254. A printhead module according to claim 1218, including at least one row that comprises a plurality of sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, such that, for each set of nozzles, a fire signal is provided in accordance with the sequence: [nozzle position 1, nozzle position n, nozzle position 2, nozzle position (n-1), ... , nozzle position x], wherein nozzle position x is at or adjacent the centre of the set of nozzles.

1255. A printhead module according to claim 1218, including at least one row that comprises a plurality of adjacent sets of n adjacent nozzles, each of the nozzles being configured to expel the ink in response to a fire signal, the printhead being configured to output ink from nozzles at a first and nth position in each set of nozzles, and then each next inward pair of nozzles in each set, until:
in the event n is an even number, all of the nozzles in each set has been fired; and in the event n is an odd number, all of the nozzles but a central nozzle in each set have been fired, and then to fire the central nozzle.

1256. A printhead module according to claim 1218, for receiving dot data to be printed using at least two different inks and control data for controlling printing of the dot data, the printhead module including a communication input for receiving the dot data for the at least two colors and the control data.

1257. A printhead module according to claim 1218, having a plurality of rows of nozzles configured to extend, in use, across at least part of a printable pagewidth, the nozzles in each row being grouped into at least first and second fire groups, the printhead module being configured to sequentially fire, for each row, the nozzles of each fire group, such that each nozzle in the sequence from each fire group is fired simultaneously with respective corresponding nozzles in the sequence in the other fire groups, wherein the nozzles are fired row by row such that the nozzles of each row are all fired before the nozzles of each subsequent row.

1258. A printhead module according to claim 1218, comprising at least first and second rows configured to print ink of a similar type or color, at least some nozzles in the first row being aligned with respective corresponding nozzles in the second row in a direction of intended media travel relative to the printhead, the printhead module being configurable such that the nozzles in the first and second pairs of rows are fired such that some dots output to print media are printed to by nozzles from the first pair of rows and at least some other dots output to print media are printed to by nozzles from the second pair of rows.

1259. A printhead module according to claim 1218, in communication with a printer controller for providing data to a printhead module that includes:
at least one row of print nozzles;
at least first and second shift registers for shifting in dot data supplied from a data source, wherein each shift register feeds dot data to a group of nozzles, and wherein each of the groups of the nozzles is interleaved with at least one of the other groups of the nozzles.

1260. A printhead module according to claim 1218, having a plurality of nozzles for expelling ink, the printhead module including a plurality of thermal sensors, each of the thermal sensors being configured to respond to a temperature at or adjacent at least one of the nozzles, the printhead module being configured to modify operation of the nozzles in response to the temperature rising above a first threshold.

1261. A printhead module according to claim 1218, comprising a plurality of rows, each of the rows comprising a plurality of nozzles for ejecting ink, wherein the printhead module includes at least first and second rows configured to print ink of a similar type or color, and being configured such that, in the event a nozzle in the first row is faulty, a corresponding nozzle in the second row prints an ink dot at a position on print media at or adjacent a position where the faulty nozzle would otherwise have printed it.

1262. A printhead module having a plurality of rows of nozzles configured to extend, in use, across at least part of a printable pagewidth, the nozzles in each row being grouped into at least first and second fire groups, the printhead module being configured to sequentially fire, for each row, the nozzles of each fire group, such that each nozzle in the sequence from each fire group is fired simultaneously with respective corresponding nozzles in the sequence in the other fire groups, wherein the nozzles are fired row by row such that the nozzles of each row are all fired before the nozzles of each subsequent row.

1263. A printhead module according to claim 1262 wherein the rows are disposed in pairs extending generally transverse to a direction media is to be moved relative to the printhead.

1264. A printhead module according to claim 1263, wherein the rows in each pair of rows are configured to print the same color ink as each other.

1265. A printhead module according to claim 1264, wherein the rows in each pair of rows share an ink supply.

1266. A printhead module according to claim 1262, wherein the rows in each pair of rows are offset with respect to each other.

1267. A printhead module according to claim 1262 configured to fire the nozzles such that at least some ink dots from one row land on top of dots previously deposited by one or more of the other rows.

1268. A printhead module according to claim 1262 operable in at least two fire modes, wherein at least some of the at least two fire modes define relatively different numbers of nozzles in each of the fire groups.

1269. A printhead module according to claim 1268, wherein at least some of the at least two fire groups define relatively different fire group sequences.

1270. A printhead comprising a plurality of printhead modules according to claim 1262.

1271. A printhead according to claim 1270, wherein the printhead is a pagewidth printhead.

1272. A printhead module according to claim 1262 configured to receive dot data to which a method of at least partially compensating for errors in ink dot placement by at least one of a plurality of nozzles due to erroneous rotational displacement of a printhead module relative to a carrier has been applied, the nozzles being disposed on the printhead module, the method comprising the steps of:
determining the rotational displacement;
determining at least one correction factor that at least partially compensates for the ink dot displacement; and using the correction factor to alter the output of the ink dots to at least partially compensate for the rotational displacement.

1273. A printhead module according to claim 1262 configured to receive dot data to which a method of expelling ink has been applied, the method being applied to a printhead module including at least one row that comprises a plurality of adjacent sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, the method comprising providing, for each set of nozzles, a fire signal in accordance with the sequence: [nozzle position 1, nozzle position n, nozzle position 2, nozzle position (n-1), ... , nozzle position x], wherein nozzle position x is at or adjacent the centre of the set of nozzles.

1274. A printhead module according to claim 1262 configured to receive dot data to which a method of expelling ink has been applied, the method being applied to a printhead module including at least one row that comprises a plurality of sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, the method comprising the steps of:
(a). providing a fire signal to nozzles at a first and nth position in each set of nozzles;
(b). providing a fire signal to the next inward pair of nozzles in each set;
(c). in the event n is an even number, repeating step (b) until all of the nozzles in each set has been fired; and (d). in the event n is an odd number, repeating step (b) until all of the nozzles but a central nozzle in each set have been fired, and then firing the central nozzle.

1275. A printhead module according to claim 1262 having been manufactured in accordance with a method of manufacturing a plurality of printhead modules, at least some of which are capable of being combined in pairs to form bilithic pagewidth printheads, the method comprising the step of laying out each of the plurality of printhead modules on a wafer substrate, wherein at least one of the printhead modules is right-handed and at least another is left-handed.

1276. A printhead module according to claim 1262 including:
at least one row of print nozzles;
at least two shift registers for shifting in dot data supplied from a data source to each of the at least one rows, wherein each print nozzle obtains dot data to be fired from an element of one of the shift registers.

1277. A printhead module according to claim 1262 installed in a printer comprising:
a printhead comprising at least the first elongate printhead module, the at least one printhead module including at least one row of print nozzles for expelling ink; and at least first and second printer controllers configured to receive print data and process the print data to output dot data to the printhead, wherein the first and second printer controllers are connected to a common input of the printhead.

1278. A printhead module according to claim 1262 installed in a printer comprising:
a printhead comprising first and second elongate printhead modules, the printhead modules being parallel to each other and being disposed end to end on either side of a join region;
at least first and second printer controllers configured to receive print data and process the print data to output dot data to the printhead, wherein the first printer controller outputs dot data only to the first printhead module and the second printer controller outputs dot data only to the second printhead module, wherein the printhead modules are configured such that no dot data passes between them.

1279. A printhead module according to claim 1262 installed in a printer comprising:
a printhead comprising first and second elongate printhead modules, the printhead modules being parallel to each other and being disposed end to end on either side of a join region, wherein the first printhead module is longer than the second printhead module;
at least first and second printer controllers configured to receive print data and process the print data to output dot data to the printhead, wherein: the first printer controller outputs dot data to both the first printhead module and the second printhead module; and the second printer controller outputs dot data only to the second printhead module.

1280. A printhead module according to claim 1262 installed in a printer comprising:
a printhead comprising first and second elongate printhead modules, the printhead modules being parallel to each other and being disposed end to end on either side of a join region, wherein the first printhead module is longer than the second printhead module;
at least first and second printer controllers configured to receive print data and process the print data to output dot data for the printhead, wherein: the first printer controller outputs dot data to both the first printhead module and the second controller; and the second printer controller outputs dot data to the second printhead module, wherein the dot data output by the second printer controller includes dot data it generates and at least some of the dot data received from the first printer controller.

1281. A printhead module according to claim 1262 in communication with a printer controller for supplying dot data to at least one printhead module and at least partially compensating for errors in ink dot placement by at least one of a plurality of nozzles on the printhead module due to erroneous rotational displacement of the printhead module relative to a carrier, the printer being configured to:
access a correction factor associated with the at least one printhead module;
determine an order in which at least some of the dot data is supplied to at least one of the at least one printhead modules, the order being determined at least partly on the basis of the correction factor, thereby to at least partially compensate for the rotational displacement; and supply the dot data to the printhead module.

1282. A printhead module according to claim 1262 in communication with a printer controller for supplying dot data to a printhead module having a plurality of nozzles for expelling ink, the printhead module including a plurality of thermal sensors, each of the thermal sensors being configured to respond to a temperature at or adjacent at least one of the nozzles, the printer controller being configured to modify operation of at least some of the nozzles in response to the temperature rising above a first threshold.

1283. A printhead module according to claim 1262 in communication with a printer controller for controlling a printhead comprising at least one monolithic printhead module, the at least one printhead module having a plurality of rows of nozzles configured to extend, in use, across at least part of a printable pagewidth of the printhead, the nozzles in each row being grouped into at least first and second fire groups, the printhead module being configured to sequentially fire, for each row, the nozzles of each fire group, such that each nozzle in the sequence from each fire group is fired simultaneously with respective corresponding nozzles in the sequence in the other fire groups, wherein the nozzles are fired row by row such that the nozzles of each row are all fired before the nozzles of each subsequent row, wherein the printer controller is configured to provide one or more control signals that control the order of firing of the nozzles.

1284. A printhead module according to claim 1262 in communication with a printer controller for outputting to a printhead module:
dot data to be printed with at least two different inks; and control data for controlling printing of the dot data;
the printer controller including at least one communication output, each or the communication output being configured to output at least some of the control data and at least some of the dot data for the at least two inks.

1285. A printhead module according to claim 1262 including at least one row of printhead nozzles, at least one row including at least one displaced row portion, the displacement of the row portion including a component in a direction normal to that of a pagewidth to be printed.

1286. A printhead module according to claim 1262 in communication with a printer controller for supplying print data to at least one printhead module capable of printing a maximum of n of channels of print data, the at least one printhead module being configurable into:
a first mode, in which the printhead module is configured to receive data for a first number of the channels; and a second mode, in which the printhead module is configured to receive print data for a second number of the channels, wherein the first number is greater than the second number, wherein the printer controller is selectively configurable to supply dot data for the first and second modes.

1287. A printhead module according to claim 1262 in communication with a printer controller for supplying data to a printhead comprising a plurality of printhead modules, the printhead being wider than a reticle step used in forming the modules, the printhead comprising at least two types of the modules, wherein each type is determined by its geometric shape in plan.

1288. A printhead module according to claim 1262 used in conjunction with a printer controller for supplying one or more control signals to a printhead module, the printhead module including at least one row that comprises a plurality of sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, such that:
(a). a fire signal is provided to nozzles at a first and nth position in each set of nozzles;
(b). a fire signal is provided to the next inward pair of nozzles in each set;
(c). in the event n is an even number, step (b) is repeated until all of the nozzles in each set has been fired;
and (d). in the event n is an odd number, step (b) is repeated until all of the nozzles but a central nozzle in each set have been fired, and then the central nozzle is fired.

1289. A printhead module according to claim 1262 used in conjunction with a printer controller for supplying one or more control signals to a printhead module, the printhead module including at least one row that comprises a plurality of adjacent sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, the method comprising providing, for each set of nozzles, a fire signal in accordance with the sequence: [nozzle position 1, nozzle position n, nozzle position 2, nozzle position (n-1), ... , nozzle position x], wherein nozzle position x is at or adjacent the centre of the set of nozzles.

1290. A printhead module according to claim 1262 in communication with a printer controller for supplying dot data to a printhead module comprising at least first and second rows configured to print ink of a similar type or color, at least some nozzles in the first row being aligned with respective corresponding nozzles in the second row in a direction of intended media travel relative to the printhead, the printhead module being configurable such that the nozzles in the first and second pairs of rows are fired such that some dots output to print media are printed to by nozzles from the first pair of rows and at least some other dots output to print media are printed to by nozzles from the second pair of rows, the printer controller being configurable to supply dot data to the printhead module for printing.

1291. A printhead module according to claim 1262 in communication with a printer controller for supplying dot data to at least one printhead module, the at least one printhead module comprising a plurality of rows, each of the rows comprising a plurality of nozzles for ejecting ink, wherein the printhead module includes at least first and second rows configured to print ink of a similar type or color, the printer controller being configured to supply the dot data to the at least one printhead module such that, in the event a nozzle in the first row is faulty, a corresponding nozzle in the second row prints an ink dot at a position on print media at or adjacent a position where the faulty nozzle would otherwise have printed it.

1292. A printhead module according to claim 1262 in communication with a printer controller for receiving first data and manipulating the first data to produce dot data to be printed, the print controller including at least two serial outputs for supplying the dot data to at least one printhead.

1293. A printhead module according to claim 1262 including:
at least one row of print nozzles;
at least first and second shift registers for shifting in dot data supplied from a data source, wherein each shift register feeds dot data to a group of nozzles, and wherein each of the groups of the nozzles is interleaved with at least one of the other groups of the nozzles.

1294. A printhead module according to claim 1 being capable of printing a maximum of n of channels of print data, the printhead being configurable into:
a first mode, in which the printhead is configured to receive print data for a first number of the channels; and a second mode, in which the printhead is configured to receive print data for a second number of the channels, wherein the first number is greater than the second number.

1295. A printhead comprising a plurality of printhead modules according to claim 1262 the printhead being wider than a reticle step used in forming the modules, the printhead comprising at least two types of the modules, wherein each type is determined by its geometric shape in plan.

1296. A printhead module according to claim 1262 including at least one row that comprises a plurality of sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, such that, for each set of nozzles, a fire signal is provided in accordance with the sequence: [nozzle position 1, nozzle position n, nozzle position 2, nozzle position (n-1), ... , nozzle position x], wherein nozzle position x is at or adjacent the centre of the set of nozzles.

1297. A printhead module according to claim 1262 including at least one row that comprises a plurality of adjacent sets of n adjacent nozzles, each of the nozzles being configured to expel the ink in response to a fire signal, the printhead being configured to output ink from nozzles at a first and nth position in each set of nozzles, and then each next inward pair of nozzles in each set, until:
in the event n is an even number, all of the nozzles in each set has been fired; and in the event n is an odd number, all of the nozzles but a central nozzle in each set have been fired, and then to fire the central nozzle.

1298. A printhead module according to claim 1262 for receiving dot data to be printed using at least two different inks and control data for controlling printing of the dot data, the printhead module including a communication input for receiving the dot data for the at least two colors and the control data.

1299. A printhead module according to claim 1262 including at least one row of printhead nozzles, at least one row including at least one displaced row portion, the displacement of the row portion including a component in a direction normal to that of a pagewidth to be printed.

1300. A printhead module according to claim 1262 comprising at least first and second rows configured to print ink of a similar type or color, at least some nozzles in the first row being aligned with respective corresponding nozzles in the second row in a direction of intended media travel relative to the printhead, the printhead module being configurable such that the nozzles in the first and second pairs of rows are fired such that some dots output to print media are printed to by nozzles from the first pair of rows and at least some other dots output to print media are printed to by nozzles from the second pair of rows.

1301. A printhead module according to claim 1262 in communication with a printer controller for providing data to a printhead module that includes:
at least one row of print nozzles;
at least first and second shift registers for shifting in dot data supplied from a data source, wherein each shift register feeds dot data to a group of nozzles, and wherein each of the groups of the nozzles is interleaved with at least one of the other groups of the nozzles.

1302. A printhead module according to claim 1262 having a plurality of nozzles for expelling ink, the printhead module including a plurality of thermal sensors, each of the thermal sensors being configured to respond to a temperature at or adjacent at least one of the nozzles, the printhead module being configured to modify operation of the nozzles in response to the temperature rising above a first threshold.

1303. A printhead module according to claim 1262 comprising a plurality of rows, each of the rows comprising a plurality of nozzles for ejecting ink, wherein the printhead module includes at least first and second rows configured to print ink of a similar type or color, and being configured such that, in the event a nozzle in the first row is faulty, a corresponding nozzle in the second row prints an ink dot at a position on print media at or adjacent a position where the faulty nozzle would otherwise have printed it.

1304. A printhead module according to claim 1262 comprising a plurality of the rows, the printhead module being configured to fire each nozzle in each row simultaneously with the nozzle or nozzles at the same position in the other rows.

1305. A printhead module according to claim 1262 including a plurality of pairs of the rows, each pair of rows including an odd row and an even row, the odd and even rows in each pair being offset from each other in both x and y directions relative to an intended direction of print media movement relative to the printhead, the printhead module being configured to cause firing of at least a plurality of the odd rows prior to firing any of the even rows, or vice versa.

1306. A printhead module according to claim 1305, wherein all the odd rows are fired before any of the even rows are fired, or vice versa.

1307. A printhead module according to claim 1305, wherein all the odd rows, or the even rows, or both, are fired in a predetermined order.

1308. A printhead module according to claim 1307, configurable such that the predetermined order is selectable from a plurality of predetermined available orders.

1309. A printhead module according to claim 1305, wherein the predetermined order is sequential.

1310. A printhead module according to claim 1309, configurable such that the predetermined order can commence at any of a plurality of the rows.

1311. A printhead module comprising at least first and second rows configured to print ink of a similar type or color, at least some nozzles in the first row being aligned with respective corresponding nozzles in the second row in a direction of intended media travel relative to the printhead, the printhead module being configurable such that the nozzles in the first and second rows are fired such that some dots output to print media are printed to by nozzles from the first row and at least some other dots output to print media are printed to by nozzles from the second row.

1312. A printhead module according to claim 1311, controllable such that either of the nozzles in each aligned pair of nozzles in the first and second rows can be selected to output ink for a selected dot to be printed on the print media.

1313. A printhead module according to claim 1312, wherein, in the event a nozzle in the first row is faulty, the corresponding nozzle in the second row is selected to output ink for a dot for which the faulty nozzle would otherwise have output ink.

1314. A printhead module according to claim 1312, including a plurality of sets of the first and second rows.

1315. A printhead module according to claim 1314, wherein each of the sets of the first and second rows is configured to print in a single color or ink type.

1316. A printhead module according to claim 1315, wherein the first and second rows in at least one of the sets are separated by one or more rows from the other set or sets.

1317. A printhead module according to claim 1311, wherein each of the rows includes an odd sub-row and an even sub-row, the odd and even sub-rows being offset with respect to each other in a direction of intended print media travel relative to the printhead.

1318. A printhead module according to claim 1317, wherein the odd and even sub-rows are transversely offset relative to each other.

1319. A printhead module according to claim 1311, configured such that the first and second rows are fired alternately.

1320. A printhead comprising a plurality of printhead modules according to claim 1311.

1321. A printhead according to claim 1320, the printhead being a pagewidth printhead.

1322. A printhead module according to claim 1311, configured to receive dot data to which a method of at least partially compensating for errors in ink dot placement by at least one of a plurality of nozzles due to erroneous rotational displacement of a printhead module relative to a carrier has been applied, the nozzles being disposed on the printhead module, the method comprising the steps of:
determining the rotational displacement;
determining at least one correction factor that at least partially compensates for the ink dot displacement; and using the correction factor to alter the output of the ink dots to at least partially compensate for the rotational displacement.

1323. A printhead module according to claim 1311, configured to receive dot data to which a method of expelling ink has been applied, the method being applied to a printhead module including at least one row that comprises a plurality of adjacent sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, the method comprising providing, for each set of nozzles, a fire signal in accordance with the sequence: [nozzle position 1, nozzle position n, nozzle position 2, nozzle position (n-1), ... , nozzle position x], wherein nozzle position x is at or adjacent the centre of the set of nozzles.

1324. A printhead module according to claim 1311, configured to receive dot data to which a method of expelling ink has been applied, the method being applied to a printhead module including at least one row that comprises a plurality of sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, the method comprising the steps of:
(a). providing a fire signal to nozzles at a first and nth position in each set of nozzles;
(b). providing a fire signal to the next inward pair of nozzles in each set;
(c). in the event n is an even number, repeating step (b) until all of the nozzles in each set has been fired; and (d). in the event n is an odd number, repeating step (b) until all of the nozzles but a central nozzle in each set have been fired, and then firing the central nozzle.

1325. A printhead module according to claim 1311, having been manufactured in accordance with a method of manufacturing a plurality of printhead modules, at least some of which are capable of being combined in pairs to form bilithic pagewidth printheads, the method comprising the step of laying out each of the plurality of printhead modules on a wafer substrate, wherein at least one of the printhead modules is right-handed and at least another is left-handed.

1326. A printhead module according to claim 1311, including:
at least one row of print nozzles;
at least two shift registers for shifting in dot data supplied from a data source to each of the at least one rows, wherein each print nozzle obtains dot data to be fired from an element of one of the shift registers.

1327. A printhead module according to claim 1311, installed in a printer comprising:
a printhead comprising at least the first elongate printhead module, the at least one printhead module including at least one row of print nozzles for expelling ink; and at least first and second printer controllers configured to receive print data and process the print data to output dot data to the printhead, wherein the first and second printer controllers are connected to a common input of the printhead.

1328. A printhead module according to claim 1311, installed in a printer comprising:
a printhead comprising fust and second elongate printhead modules, the printhead modules being parallel to each other and being disposed end to end on either side of a join region;
at least fust and second printer controllers configured to receive print data and process the print data to output dot data to the printhead, wherein the first printer controller outputs dot data only to the first printhead module and the second printer controller outputs dot data only to the second printhead module, wherein the printhead modules are configured such that no dot data passes between them.

1329. A printhead module according to claim 1311, installed in a printer comprising:
a printhead comprising first and second elongate printhead modules, the printhead modules being parallel to each other and being disposed end to end on either side of a join region, wherein the first printhead module is longer than the second printhead module;
at least first and second printer controllers configured to receive print data and process the print data to output dot data to the printhead, wherein: the first printer controller outputs dot data to both the first printhead module and the second printhead module; and the second printer controller outputs dot data only to the second printhead module.

1330. A printhead module according to claim 1311, installed in a printer comprising:
a printhead comprising first and second elongate printhead modules, the printhead modules being parallel to each other and being disposed end to end on either side of a join region, wherein the first printhead module is longer than the second printhead module;
at least first and second printer controllers configured to receive print data and process the print data to output dot data for the printhead, wherein: the first printer controller outputs dot data to both the first printhead module and the second controller, and the second printer controller outputs dot data to the second printhead module, wherein the dot data output by the second printer controller includes dot data it generates and at least some of the dot data received from the first printer controller.

1331. A printhead module according to claim 1311, in communication with a printer controller for supplying dot data to at least one printhead module and at least partially compensating for errors in ink dot placement by at least one of a plurality of nozzles on the printhead module due to erroneous rotational displacement of the printhead module relative to a carrier, the printer being configured to:
access a correction factor associated with the at least one printhead module;
determine an order in which at least some of the dot data is supplied to at least one of the at least one printhead modules, the order being determined at least partly on the basis of the correction factor, thereby to at least partially compensate for the rotational displacement and supply the dot data to the printhead module.

1332. A printhead module according to claim 1311, in communication with a printer controller for supplying dot data to a printhead module having a plurality of nozzles for expelling ink, the printhead module including a plurality of thermal sensors, each of the thermal sensors being configured to respond to a temperature at or adjacent at least one of the nozzles, the printer controller being configured to modify operation of at least some of the nozzles in response to the temperature rising above a first threshold.

1333. A printhead module according to claim 1311, in communication with a printer controller for controlling a printhead comprising at least one monolithic printhead module, the at least one printhead module having a plurality of rows of nozzles configured to extend, in use, across at least part of a printable pagewidth of the printhead, the nozzles in each row being grouped into at least first and second fire groups, the printhead module being configured to sequentially fire, for each row, the nozzles of each fire group, such that each nozzle in the sequence from each fire group is fired simultaneously with respective corresponding nozzles in the sequence in the other fire groups, wherein the nozzles are fired row by row such that the nozzles of each row are all fired before the nozzles of each subsequent row, wherein the printer controller is configured to provide one or more control signals that control the order of firing of the nozzles.

1334. A printhead module according to claim 1311, in communication with a printer controller for outputting to a printhead module:
dot data to be printed with at least two different inks; and control data for controlling printing of the dot data;
the printer controller including at least one communication output, each or the communication output being configured to output at least some of the control data and at least some of the dot data for the at least two inks.

1335. A printhead module according to claim 1311, including at least one row of printhead nozzles, at least one row including at least one displaced row portion, the displacement of the row portion including a component in a direction normal to that of a pagewidth to be printed.

1336. A printhead module according to claim 1311, in communication with a printer controller for supplying print data to at least one printhead module capable of printing a maximum of n of channels of print data, the at least one printhead module being configurable into:
a first mode, in which the printhead module is configured to receive data for a first number of the channels; and a second mode, in which the printhead module is configured to receive print data for a second number of the channels, wherein the first number is greater than the second number;
wherein the printer controller is selectively configurable to supply dot data for the first and second modes.

1337. A printhead module according to claim 1311, in communication with a printer controller for supplying data to a printhead comprising a plurality of printhead modules, the printhead being wider than a reticle step used in forming the modules, the printhead comprising at least two types of the modules, wherein each type is determined by its geometric shape in plan.

1338. A printhead module according to claim 1311, used in conjunction with a printer controller for supplying one or more control signals to a printhead module, the printhead module including at least one row that comprises a plurality of sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, such that:
(a). a fire signal is provided to nozzles at a first and nth position in each set of nozzles;
(b). a fire signal is provided to the next inward pair of nozzles in each set;
(c). in the event n is an even number, step (b) is repeated until all of the nozzles in each set has been fired;
and (d). in the event n is an odd number, step (b) is repeated until all of the nozzles but a central nozzle in each set have been fired, and then the central nozzle is fired.

1339. A printhead module according to claim 1311, used in conjunction with a printer controller for supplying one or more control signals to a printhead module, the printhead module including at least one row that comprises a plurality of adjacent sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, the method comprising providing, for each set of nozzles, a fire signal in accordance with the sequence: [nozzle position 1, nozzle position n, nozzle position 2, nozzle position (n-1), ... , nozzle position x], wherein nozzle position x is at or adjacent the centre of the set of nozzles.

1340. A printhead module according to claim 1311, in communication with a printer controller for supplying dot data to a printhead module comprising at least first and second rows configured to print ink of a similar type or color, at least some nozzles in the first row being aligned with respective corresponding nozzles in the second row in a direction of intended media travel relative to the printhead, the printhead module being configurable such that the nozzles in the first and second pairs of rows are fired such that some dots output to print media are printed to by nozzles from the first pair of rows and at least some other dots output to print media are printed to by nozzles from the second pair of rows, the printer controller being configurable to supply dot data to the printhead module for printing.

1341. A printhead module according to claim 1311, in communication with a printer controller for supplying dot data to at least one printhead module, the at least one printhead module comprising a plurality of rows, each of the rows comprising a plurality of nozzles for ejecting ink, wherein the printhead module includes at least first and second rows configured to print ink of a similar type or color, the printer controller being configured to supply the dot data to the at least one printhead module such that, in the event a nozzle in the first row is faulty, a corresponding nozzle in the second row prints an ink dot at a position on print media at or adjacent a position where the faulty nozzle would otherwise have printed it.

1342. A printhead module according to claim 1311, in communication with a printer controller for receiving first data and manipulating the first data to produce dot data to be printed, the print controller including at least two serial outputs for supplying the dot data to at least one printhead.

1343. A printhead module according to claim 1311, including:
at least one row of print nozzles;
at least first and second shift registers for shifting in dot data supplied from a data source, wherein each shift register feeds dot data to a group of nozzles, and wherein each of the groups of the nozzles is interleaved with at least one of the other groups of the nozzles.

1344. A printhead module according to claim 1 being capable of printing a maximum of n of channels of print data, the printhead being configurable into:
a first mode, in which the printhead is configured to receive print data for a first number of the channels; and a second mode, in which the printhead is configured to receive print data for a second number of the channels, wherein the first number is greater than the second number.

1345. A printhead comprising a plurality of printhead modules according to claim 1311, the printhead being wider than a reticle step used in forming the modules, the printhead comprising at least two types of the modules, wherein each type is determined by its geometric shape in plan.

1346. A printhead module according to claim 1311, including at least one row that comprises a plurality of sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, such that, for each set of nozzles, a fire signal is provided in accordance with the sequence: [nozzle position 1, nozzle position n, nozzle position 2, nozzle position (n-1), ... , nozzle position x], wherein nozzle position x is at or adjacent the centre of the set of nozzles.

1347. A printhead module according to claim 1311, including at least one row that comprises a plurality of adjacent sets of n adjacent nozzles, each of the nozzles being configured to expel the ink in response to a fire signal, the printhead being configured to output ink from nozzles at a first and with position in each set of nozzles, and then each next inward pair of nozzles in each set, until:
in the event n is an even number, all of the nozzles in each set has been fired; and in the event n is an odd number, all of the nozzles but a central nozzle in each set have been fired, and then to fire the central nozzle.

1348. A printhead module according to claim 1311, for receiving dot data to be printed using at least two different inks and control data for controlling printing of the dot data, the printhead module including a communication input for receiving the dot data for the at least two colors and the control data.

1349. A printhead module according to claim 1311, including at least one row of printhead nozzles, at least one row including at least one displaced row portion, the displacement of the row portion including a component in a direction normal to that of a pagewidth to be printed.

1350. A printhead module according to claim 1311, having a plurality of rows of nozzles configured to extend, in use, across at least part of a printable pagewidth, the nozzles in each row being grouped into at least first and second fire groups, the printhead module being configured to sequentially fire, for each row, the nozzles of each fire group, such that each nozzle in the sequence from each fire group is fired simultaneously with respective corresponding nozzles in the sequence in the other fire groups, wherein the nozzles are fired row by row such that the nozzles of each row are all fired before the nozzles of each subsequent row.

1351. A printhead module according to claim 1311, in communication with a printer controller for providing data to a printhead module that includes:
at least one row of print nozzles;
at least first and second shift registers for shifting in dot data supplied from a data source, wherein each shift register feeds dot data to a group of nozzles, and wherein each of the groups of the nozzles is interleaved with at least one of the other groups of the nozzles.

1352. A printhead module according to claim 1311, having a plurality of nozzles for expelling ink, the printhead module including a plurality of thermal sensors, each of the thermal sensors being configured to respond to a temperature at or adjacent at least one of the nozzles, the printhead module being configured to modify operation of the nozzles in response to the temperature rising above a first threshold.

1353. A printhead module according to claim 1311, comprising a plurality of rows, each of the rows comprising a plurality of nozzles for ejecting ink, wherein the printhead module includes at least first and second rows configured to print ink of a similar type or color, and being configured such that, in the event a nozzle in the first row is faulty, a corresponding nozzle in the second row prints an ink dot at a position on print media at or adjacent a position where the faulty nozzle would otherwise have printed it.

1354. A printer controller for providing data to a printhead module that includes:
at least one row of print nozzles;
at least first and second shift registers for shifting in dot data supplied from a data source, wherein each shift register feeds dot data to a group of nozzles, and wherein each of the groups of the nozzles is interleaved with at least one of the other groups of the nozzles.

1355. A printer controller according to claim 1354, wherein there is a one to one correspondence between the nozzles and respective elements of the first and second shift registers.

1356. A printer controller according to claim 1355, wherein each of the shift registers supplies dot data to about half of the nozzles in a row.

1357. A printer controller according to claim 1354, including at least one pair of rows of the nozzles, the rows in each pair being offset in a direction parallel to the rows by half the intra-row nozzle spacing.

1358. A printer controller according to claim 1357, wherein each of the at least two shift registers supplies dot data to at least some of the nozzles in at least the pair of rows.

1359. A printer controller according claim 1354, including a plurality of the rows configured to print using at least two ink channels, the nozzles for each of the ink channels being fed the dot data from at least one pair of first and second registers.

1360. A printer controller according to claim 1359, wherein the printhead module forms part of a printhead.

1361. A printer controller according to claim 1359, wherein the printhead includes a plurality of the printhead modules and the printer controller is configured to supply data to a plurality of the modules.

1362. A printer controller according to claim 1360, wherein the printhead is a pagewidth printhead comprising a plurality of the printhead modules.

1363. A printer controller according to claim 1354, for implementing a method of at least partially compensating for errors in ink dot placement by at least one of a plurality of nozzles due to erroneous rotational displacement of a printhead module relative to a carrier, the nozzles being disposed on the printhead module, the method comprising the steps of:
determining the rotational displacement;

determining at least one correction factor that at least partially compensates for the ink dot displacement; and using the correction factor to alter the output of the ink dots to at least partially compensate for the rotational displacement.

1364. A printer controller according to claim 1354 for implementing a method of expelling ink from a printhead module including at least one row that comprises a plurality of adjacent sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, the method comprising providing, for each set of nozzles, a fire signal in accordance with the sequence: [nozzle position 1, nozzle position n, nozzle position 2, nozzle position (n-1), ... , nozzle position x], wherein nozzle position x is at or adjacent the centre of the set of nozzles.

1365. A printer controller according to claim 1354, for implementing a method of expelling ink from a printhead module including at least one row that comprises a plurality of sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, the method comprising the steps of:
(a). providing a fire signal to nozzles at a first and nth position in each set of nozzles;
(b). providing a fire signal to the next inward pair of nozzles in each set;
(c). in the event n is an even number, repeating step (b) until all of the nozzles in each set has been fired; and (d). in the event n is an odd number, repeating step (b) until all of the nozzles but a central nozzle in each set have been fired, and then firing the central nozzle.

1366. A printer controller according to claim 1354, manufactured in accordance with a method of manufacturing a plurality of printhead modules, at least some of which are capable of being combined in pairs to form bilithic pagewidth printheads, the method comprising the step of laying out each of the plurality of printhead modules on a wafer substrate, wherein at least one of the printhead modules is right-handed and at least another is left-handed.

1367. A printer controller according to claim 1354, for supplying data to a printhead module including:
at least one row of print nozzles;
at least two shift registers for shifting in dot data supplied from a data source to each of the at least one rows, wherein each print nozzle obtains dot data to be fired from an element of one of the shift registers.

1368. A printer controller according to claim 1354, installed in a printer comprising:
a printhead comprising at least a first elongate printhead module, the at least one printhead module including at least one row of print nozzles for expelling ink; and at least first and second printer controllers configured to receive print data and process the print data to output dot data to the printhead, wherein the first and second printer controllers are connected to a common input of the printhead.

1369. A printer controller according to claim 1354, installed in a printer comprising:
a printhead comprising first and second elongate printhead modules, the printhead modules being parallel to each other and being disposed end to end on either side of a join region;
at least first and second printer controllers configured to receive print data and process the print data to output dot data to the printhead, wherein the first printer controller outputs dot data only to the first printhead module and the second printer controller outputs dot data only to the second printhead module, wherein the printhead modules are configured such that no dot data passes between them.

1370. A printer controller according to claim 1354, installed in a printer comprising:
a printhead comprising first and second elongate printhead modules, the printhead modules being parallel to each other and being disposed end to end on either side of a join region, wherein the first printhead module is longer than the second printhead module;
at least first and second printer controllers configured to receive print data and process the print data to output dot data to the printhead, wherein: the first printer controller outputs dot data to both the first printhead module and the second printhead module; and the second printer controller outputs dot data only to the second printhead module.

1371. A printer controller according to claim 1354, installed in a printer comprising:
a printhead comprising first and second elongate printhead modules, the printhead modules being parallel to each other and being disposed end to end on either side of a join region, wherein the first printhead module is longer than the second printhead module;
at least first and second printer controllers configured to receive print data and process the print data to output dot data for the printhead, wherein: the first printer controller outputs dot data to both the first printhead module and the second controller, and the second printer controller outputs dot data to the second printhead module, wherein the dot data output by the second printer controller includes dot data it generates and at least some of the dot data received from the first printer controller.

1372. A printer controller according to claim 1354, for supplying dot data to at least one printhead module and at least partially compensating for errors in ink dot placement by at least one of a plurality of nozzles on the printhead module due to erroneous rotational displacement of the printhead module relative to a carrier, the printer being configured to:
access a correction factor associated with the at least one printhead module;
determine an order in which at least some of the dot data is supplied to at least one of the at least one printhead modules, the order being determined at least partly on the basis of the correction factor, thereby to at least partially compensate for the rotational displacement; and supply the dot data to the printhead module.

1373. A printer controller according to claim 1354, for supplying dot data to a printhead module having a plurality of nozzles for expelling ink, the printhead module including a plurality of thermal sensors, each of the thermal sensors being configured to respond to a temperature at or adjacent at least one of the nozzles, the printer controller being configured to modify operation of at least some of the nozzles in response to the temperature rising above a first threshold.

1374. A printer controller according to claim 1354, for controlling a printhead comprising at least one monolithic printhead module, the at least one printhead module having a plurality of rows of nozzles configured to extend, in use, across at least part of a printable pagewidth of the printhead, the nozzles in each row being grouped into at least first and second fire groups, the printhead module being configured to sequentially fire, for each row, the nozzles of each fire group, such that each nozzle in the sequence from each fire group is fired simultaneously with respective corresponding nozzles in the sequence in the other fire groups, wherein the nozzles are fired row by row such that the nozzles of each row are all fired before the nozzles of each subsequent row, wherein the printer controller is configured to provide one or more control signals that control the order of firing of the nozzles.

1375. A printer controller according to claim 1354, for outputting to a printhead module:
dot data to be printed with at least two different inks; and control data for controlling printing of the dot data;
the printer controller including at least one communication output, each or the communication output being configured to output at least some of the control data and at least some of the dot data for the at least two inks.

1376. A printer controller according to claim 1354, for supplying data to a printhead module including at least one row of printhead nozzles, at least one row including at least one displaced row portion, the displacement of the row portion including a component in a direction normal to that of a pagewidth to be printed.

1377. A printer controller according to claim 1354, for supplying print data to at least one printhead module capable of printing a maximum of n of channels of print data, the at least one printhead module being configurable into:
a first mode, in which the printhead module is configured to receive data for a first number of the channels; and a second mode, in which the printhead module is configured to receive print data for a second number of the channels, wherein the first number is greater than the second number;
wherein the printer controller is selectively configurable to supply dot data for the first and second modes.

1378. A printer controller according to claim 1354, for supplying data to a printhead comprising a plurality of printhead modules, the printhead being wider than a reticle step used in forming the modules, the printhead comprising at least two types of the modules, wherein each type is determined by its geometric shape in plan.

1379. A printer controller according to claim 1354, for supplying one or more control signals to a printhead module, the printhead module including at least one row that comprises a plurality of sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, such that:
(a). a fire signal is provided to nozzles at a first and nth position in each set of nozzles;
(b). a fire signal is provided to the next inward pair of nozzles in each set;
(c). in the event n is an even number, step (b) is repeated until all of the nozzles in each set has been fired;
and (d). in the event n is an odd number, step (b) is repeated until all of the nozzles but a central nozzle in each set have been fired, and then the central nozzle is fired.

1380. A printer controller according to claim 1354, for supplying one or more control signals to a printhead module, the printhead module including at least one row that comprises a plurality of adjacent sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, the method comprising providing, for each set of nozzles, a fire signal in accordance with the sequence: [nozzle position 1, nozzle position n, nozzle position 2, nozzle position (n-1), ... , nozzle position x], wherein nozzle position x is at or adjacent the centre of the set of nozzles.

1381. A printer controller according to claim 1354, for supplying dot data to a printhead module comprising at least first and second rows configured to print ink of a similar type or color, at least some nozzles in the first row being aligned with respective corresponding nozzles in the second row in a direction of intended media travel relative to the printhead, the printhead module being configurable such that the nozzles in the first and second pairs of rows are fired such that some dots output to print media are printed to by nozzles from the first pair of rows and at least some other dots output to print media are printed to by nozzles from the second pair of rows, the printer controller being configurable to supply dot data to the printhead module for printing.

1382. A printer controller according to claim 1354, for supplying dot data to at least one printhead module, the at least one printhead module comprising a plurality of rows, each of the rows comprising a plurality of nozzles for ejecting ink, wherein the printhead module includes at least first and second rows configured to print ink of a similar type or color, the printer controller being configured to supply the dot data to the at least one printhead module such that, in the event a nozzle in the first row is faulty, a corresponding nozzle in the second row prints an ink dot at a position on print media at or adjacent a position where the faulty nozzle would otherwise have printed it.

1383. A printer controller according to claim 1354, for receiving first data and manipulating the first data to produce dot data to be printed, the print controller including at least two serial outputs for supplying the dot data to at least one printhead.

1384. A printer controller according to claim 1354, for supplying data to a printhead module including:
at least one row of print nozzles;
at least first and second shift registers for shifting in dot data supplied from a data source, wherein each shift register feeds dot data to a group of nozzles, and wherein each of the groups of the nozzles is interleaved with at least one of the other groups of the nozzles.

1385. A printer controller according to claim 1354, for supplying data to a printhead capable of printing a maximum of n of channels of print data, the printhead being configurable into:
a first mode, in which the printhead is configured to receive print data for a first number of the channels; and a second mode, in which the printhead is configured to receive print data for a second number of the channels, wherein the first number is greater than the second number.

1386. A printer controller according to claim 1354, for supplying data to a printhead comprising a plurality of printhead modules, the printhead being wider than a reticle step used in forming the modules, the printhead comprising at least two types of the modules, wherein each type is determined by its geometric shape in plan.

1387. A printer controller according to claim 1354, for supplying data to a printhead module including at least one row that comprises a plurality of sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, such that, for each set of nozzles, a fire signal is provided in accordance with the sequence: [nozzle position 1, nozzle position n, nozzle position 2, nozzle position (n-1), ... , nozzle position x], wherein nozzle position x is at or adjacent the centre of the set of nozzles.

1388. A printer controller according to claim 1354, for supplying data to a printhead module including at least one row that comprises a plurality of adjacent sets of n adjacent nozzles, each of the nozzles being configured to expel the ink in response to a fire signal, the printhead being configured to output ink from nozzles at a first and nth position in each set of nozzles, and then each next inward pair of nozzles in each set, until:
in the event n is an even number, all of the nozzles in each set has been fired; and in the event n is an odd number, all of the nozzles but a central nozzle in each set have been fired, and then to fire the central nozzle.

1389. A printer controller according to claim 1354, for supplying data to a printhead module for receiving dot data to be printed using at least two different inks and control data for controlling printing of the dot data, the printhead module including a communication input for receiving the dot data for the at least two colors and the control data.

1390. A printer controller according to claim 1354, for supplying data to a printhead module including at least one row of printhead nozzles, at least one row including at least one displaced row portion, the displacement of the row portion including a component in a direction normal to that of a pagewidth to be printed.

1391. A printer controller according to claim 1354, for supplying data to a printhead module having a plurality of rows of nozzles configured to extend, in use, across at least part of a printable pagewidth, the nozzles in each row being grouped into at least first and second fire groups, the printhead module being configured to sequentially fire, for each row, the nozzles of each fire group, such that each nozzle in the sequence from each fire group is fired simultaneously with respective corresponding nozzles in the sequence in the other fire groups, wherein the nozzles are fired row by row such that the nozzles of each row are all fired before the nozzles of each subsequent row.

1392. A printer controller according to claim 1354, for supplying data to a printhead module comprising at least first and second rows configured to print ink of a similar type or color, at least some nozzles in the first row being aligned with respective corresponding nozzles in the second row in a direction of intended media travel relative to the printhead, the printhead module being configurable such that the nozzles in the first and second pairs of rows are fired such that some dots output to print media are printed to by nozzles from the first pair of rows and at least some other dots output to print media are printed to by nozzles from the second pair of rows.

1393. A printer controller according to claim 1354, for supplying data to a printhead module having a plurality of nozzles for expelling ink, the printhead module including a plurality of thermal sensors, each of the thermal sensors being configured to respond to a temperature at or adjacent at least one of the nozzles, the printhead module being configured to modify operation of the nozzles in response to the temperature rising above a first threshold.

1394. A printer controller according to claim 1354, for supplying data to a printhead module comprising a plurality of rows, each of the rows comprising a plurality of nozzles for ejecting ink, wherein the printhead module includes at least first and second rows configured to print ink of a similar type or color, and being configured such that, in the event a nozzle in the first row is faulty, a corresponding nozzle in the second row prints an ink dot at a position on print media at or adjacent a position where the faulty nozzle would otherwise have printed it.

1395. A printhead module having a plurality of nozzles for expelling ink, the printhead module including a plurality of thermal sensors, each of the thermal sensors being configured to respond to a temperature at or adjacent at least one of the nozzles, the printhead module being configured to modify operation of the nozzles in response to the temperature rising above a first threshold.

1396. A printhead module according to claim 1395, configured to modify the operation of the nozzles at or adjacent the at least one thermal sensor, such that operation of nozzles not at or adjacent the at least one thermal sensor is not modified.

1397. A printhead module according to claim 1396, wherein each thermal sensor is associated with a predetermined group of the nozzles, the nozzles in the predetermined group being those for which the operation is modified.

1398. A printhead module according to claim 1397, wherein each thermal sensor is associated with a single nozzle.

1399. A printhead module according to claim 1398, wherein the modification includes preventing operation of the nozzle.

1400. A printhead module according to claim 1399, wherein the modification includes preventing operation of the nozzle for a predetermined period.

1401. A printhead module according to claim 1399, wherein the modification includes preventing operation of the nozzle until the temperature drops below a second threshold.

1402. A printhead module according to claim 1401, wherein the second threshold is lower than the first threshold.

1403. A printhead module according to claim 1402, wherein the second threshold is the same as the first threshold.

1404. A printhead module according to claim 1395, wherein the temperature is not determined explicitly by the at least one thermal sensor or the module.

1405. A printhead module according to claim 1395, wherein the printhead module is a thermal inkjet printhead module and each of the nozzles includes a thermal ink ejection mechanism.

1406. A printhead module according to claim 1405, wherein the thermal sensor comprises at least part of one of the thermal inkjet mechanisms.

1407. A printhead module according to claim 1406, wherein the thermal sensor comprises a heating element.

1408. A printhead module according to claim 1407, wherein the thermal sensor determines the temperature by determining a resistance of the heating element.

1409. A printhead module according to claim 1395, configured to:
output thermal information from the at least one thermal sensor to a controller, and receive control information back from the controller, the control information being indicative of the modification to make to the operation of the one or more nozzles.

1410. A printhead module according to claim 1395, further including a plurality of data latches, the data latches being configured to provide dot data to respective ones of the nozzles, at least some of the data latches being configured to receive thermal signals from respective ones of the thermal sensors during an acquisition period.

1411. A printhead module according to claim 1406, wherein the data latches are configured to form a shift register, the shift register being configured to:
shift the print data in during a print load phase;
sample the signals from the thermal sensors during a temperature load phase;
and shift the thermal signals out during an output phase.

1412. A printhead module according to claim 1411, wherein the output phase coincides with a subsequent print load phase.

1413. A printhead module according to claim 1408, further including logic circuitry configured to perform a bitwise operation on: each thermal signal as it is clocked out of the shift register; and each piece of dot data to be clocked into the shift register, such that when a thermal signal is indicative of a thermal problem with a nozzle, the logic circuitry prevents loading of data that would cause firing of that nozzle.

1414. A printhead module according to claim 1413, wherein the logic circuitry includes an AND circuit that receives as inputs the dot data and the thermal signal corresponding to the nozzle for which the dot data is intended, an output of the AND circuit being in communication with an input of the shift register.

1415. A printhead module according to claim 1395, configured to receive dot data to which a method of at least partially compensating for errors in ink dot placement by at least one of a plurality of nozzles due to erroneous rotational displacement of a printhead module relative to a carrier has been applied, the nozzles being disposed on the printhead module, the method comprising the steps of:
determining the rotational displacement;
determining at least one correction factor that at least partially compensates for the ink dot displacement; and using the correction factor to alter the output of the ink dots to at least partially compensate for the rotational displacement.

1416. A printhead module according to claim 1395, configured to receive dot data to which a method of expelling ink has been applied, the method being applied to a printhead module including at least one row that comprises a plurality of adjacent sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, the method comprising providing, for each set of nozzles, a fire signal in accordance with the sequence: [nozzle position 1, nozzle position n, nozzle position 2, nozzle position (n-1), ... , nozzle position x], wherein nozzle position x is at or adjacent the centre of the set of nozzles.

1417. A printhead module according to claim 1395, configured to receive dot data to which a method of expelling ink has been applied, the method being applied to a printhead module including at least one row that comprises a plurality of sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, the method comprising the steps of:
(a). providing a fire signal to nozzles at a first and nth position in each set of nozzles;
(b). providing a fire signal to the next inward pair of nozzles in each set;
(c). in the event n is an even number, repeating step (b) until all of the nozzles in each set has been fired; and (d). in the event n is an odd number, repeating step (b) until all of the nozzles but a central nozzle in each set have been fired, and then firing the central nozzle.

1418. A printhead module according to claim 1395, having been manufactured in accordance with a method of manufacturing a plurality of printhead modules, at least some of which are capable of being combined in pairs to form bilithic pagewidth printheads, the method comprising the step of laying out each of the plurality of printhead modules on a wafer substrate, wherein at least one of the printhead modules is right-handed and at least another is left-handed.

1419. A printhead module according to claim 1395, including:
at least one row of print nozzles;
at least two shift registers for shifting in dot data supplied from a data source to each of the at least one rows, wherein each print nozzle obtains dot data to be fired from an element of one of the shift registers.

1420. A printhead module according to claim 1395, installed in a printer comprising:

a printhead comprising at least the first elongate printhead module, the at least one printhead module including at least one row of print nozzles for expelling ink; and at least first and second printer controllers configured to receive print data and process the print data to output dot data to the printhead, wherein the first and second printer controllers are connected to a common input of the printhead.

1421. A printhead module according to claim 1395, installed in a printer comprising:
a printhead comprising first and second elongate printhead modules, the printhead modules being parallel to each other and being disposed end to end on either side of a join region;
at least first and second printer controllers configured to receive print data and process the print data to output dot data to the printhead, wherein the first printer controller outputs dot data only to the first printhead module and the second printer controller outputs dot data only to the second printhead module, wherein the printhead modules are configured such that no dot data passes between them.

1422. A printhead module according to claim 1395, installed in a printer comprising:
a printhead comprising first and second elongate printhead modules, the printhead modules being parallel to each other and being disposed end to end on either side of a join region, wherein the first printhead module is longer than the second printhead module;
at least first and second printer controllers configured to receive print data and process the print data to output dot data to the printhead, wherein: the first printer controller outputs dot data to both the first printhead module and the second printhead module; and the second printer controller outputs dot data only to the second printhead module.

1423. A printhead module according to claim 1395, installed in a printer comprising:
a printhead comprising first and second elongate printhead modules, the printhead modules being parallel to each other and being disposed end to end on either side of a join region, wherein the first printhead module is longer than the second printhead module;
at least first and second printer controllers configured to receive print data and process the print data to output dot data for the printhead, wherein: the first printer controller outputs dot data to both the first printhead module and the second controller; and the second printer controller outputs dot data to the second printhead module, wherein the dot data output by the second printer controller includes dot data it generates and at least some of the dot data received from the first printer controller.

1424. A printhead module according to claim 1395, in communication with a printer controller for supplying dot data to at least one printhead module and at least partially compensating for errors in ink dot placement by at least one of a plurality of nozzles on the printhead module due to erroneous rotational displacement of the printhead module relative to a carrier, the printer being configured to:

access a correction factor associated with the at least one printhead module;
determine an order in which at least some of the dot data is supplied to at least one of the at least one printhead modules, the order being determined at least partly on the basis of the correction factor, thereby to at least partially compensate for the rotational displacement; and supply the dot data to the printhead module.

1425. A printhead module according to claim 1395, in communication with a printer controller for supplying dot data to a printhead module having a plurality of nozzles for expelling ink, the printhead module including a plurality of thermal sensors, each of the thermal sensors being configured to respond to a temperature at or adjacent at least one of the nozzles, the printer controller being configured to modify operation of at least some of the nozzles in response to the temperature rising above a fust threshold.

1426. A printhead module according to claim 1395, in communication with a printer controller for controlling a printhead comprising at least one monolithic printhead module, the at least one printhead module having a plurality of rows of nozzles configured to extend, in use, across at least part of a printable pagewidth of the printhead, the nozzles in each row being grouped into at least first and second fire groups, the printhead module being configured to sequentially fire, for each row, the nozzles of each fire group, such that each nozzle in the sequence from each fire group is fired simultaneously with respective corresponding nozzles in the sequence in the other fire groups, wherein the nozzles are fired row by row such that the nozzles of each row are all fired before the nozzles of each subsequent row, wherein the printer controller is configured to provide one or more control signals that control the order of firing of the nozzles.

1427. A printhead module according to claim 1395, in communication with a printer controller for outputting to a printhead module:
dot data to be printed with at least two different inks; and control data for controlling printing of the dot data;
the printer controller including at least one communication output, each or the communication output being configured to output at least some of the control data and at least some of the dot data for the at least two inks.

1428. A printhead module according to claim 1395, including at least one row of printhead nozzles, at least one row including at least one displaced row portion, the displacement of the row portion including a component in a direction normal to that of a pagewidth to be printed.

1429. A printhead module according to claim 1395, in communication with a printer controller for supplying print data to at least one printhead module capable of printing a maximum of n of channels of print data, the at least one printhead module being configurable into:
a first mode, in which the printhead module is configured to receive data for a first number of the channels; and a second mode, in which the printhead module is configured to receive print data for a second number of the channels, wherein the first number is greater than the second number, wherein the printer controller is selectively configurable to supply dot data for the first and second modes.

1430. A printhead module according to claim 1395, in communication with a printer controller for supplying data to a printhead comprising a plurality of printhead modules, the printhead being wider than a reticle step used in forming the modules, the printhead comprising at least two types of the modules, wherein each type is determined by its geometric shape in plan.

1431. A printhead module according to claim 1395, used in conjunction with a printer controller for supplying one or more control signals to a printhead module, the printhead module including at least one row that comprises a plurality of sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, such that:
(a). a fire signal is provided to nozzles at a first and nth position in each set of nozzles;
(b). a fire signal is provided to the next inward pair of nozzles in each set;
(c). in the event n is an even number, step (b) is repeated until all of the nozzles in each set has been fired;
and (d). in the event n is an odd number, step (b) is repeated until all of the nozzles but a central nozzle in each set have been fired, and then the central nozzle is fired.

1432. A printhead module according to claim 1395, used in conjunction with a printer controller for supplying one or more control signals to a printhead module, the printhead module including at least one row that comprises a plurality of adjacent sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, the method comprising providing, for each set of nozzles, a fire signal in accordance with the sequence: [nozzle position 1, nozzle position n, nozzle position 2, nozzle position (n-1), ... , nozzle position x], wherein nozzle position x is at or adjacent the centre of the set of nozzles.

1433. A printhead module according to claim 1395, in communication with a printer controller for supplying dot data to a printhead module comprising at least first and second rows configured to print ink of a similar type or color, at least some nozzles in the first row being aligned with respective corresponding nozzles in the second row in a direction of intended media travel relative to the printhead, the printhead module being configurable such that the nozzles in the first and second pairs of rows are fired such that some dots output to print media are printed to by nozzles from the first pair of rows and at least some other dots output to print media are printed to by nozzles from the second pair of rows, the printer controller being conf gurable to supply dot data to the printhead module for printing.

1434. A printhead module according to claim 1395, in communication with a printer controller for supplying dot data to at least one printhead module, the at least one printhead module comprising a plurality of rows, each of the rows comprising a plurality of nozzles for ejecting ink, wherein the printhead module includes at least first and second rows configured to print ink of a similar type or color, the printer controller being configured to supply the dot data to the at least one printhead module such that, in the event a nozzle in the first row is faulty, a corresponding nozzle in the second row prints an ink dot at a position on print media at or adjacent a position where the faulty nozzle would otherwise have printed it.

1435. A printhead module according to claim 1395, in communication with a printer controller for receiving first data and manipulating the first data to produce dot data to be printed, the print controller including at least two serial outputs for supplying the dot data to at least one printhead.

1436. A printhead module according to claim 1395, including:
at least one row of print nozzles;
at least first and second shift registers for shifting in dot data supplied from a data source, wherein each shift register feeds dot data to a group of nozzles, and wherein each of the groups of the nozzles is interleaved with at least one of the other groups of the nozzles.

1437. A printhead module according to claim 1395 being capable of printing a maximum of n of channels of print data, the printhead being configurable into:
a first mode, in which the printhead is configured to receive print data for a first number of the channels; and a second mode, in which the printhead is configured to receive print data for a second number of the channels, wherein the first number is greater than the second number.

1438. A printhead comprising a plurality of printhead modules according to claim 1395, the printhead being wider than a reticle step used in forming the modules, the printhead comprising at least two types of the modules, wherein each type is determined by its geometric shape in plan.

1439. A printhead module according to claim 1395, including at least one row that comprises a plurality of sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, such that, for each set of nozzles, a fire signal is provided in accordance with the sequence: [nozzle position 1, nozzle position n, nozzle position 2, nozzle position (n-1), ... , nozzle position x], wherein nozzle position x is at or adjacent the centre of the set of nozzles.

1440. A printhead module according to claim 1395, including at least one row that comprises a plurality of adjacent sets of n adjacent nozzles, each of the nozzles being configured to expel the ink in response to a fire signal, the printhead being configured to output ink from nozzles at a first and nth position in each set of nozzles, and then each next inward pair of nozzles in each set, until:
in the event n is an even number, all of the nozzles in each set has been fired; and in the event n is an odd number, all of the nozzles but a central nozzle in each set have been fired, and then to fire the central nozzle.

1441. A printhead module according to claim 1395, for receiving dot data to be printed using at least two different inks and control data for controlling printing of the dot data, the printhead module including a communication input for receiving the dot data for the at least two colors and the control data.

1442. A printhead module according to claim 1395, including at least one row of printhead nozzles, at least one row including at least one displaced row portion, the displacement of the row portion including a component in a direction normal to that of a pagewidth to be printed.

1443. A printhead module according to claim 1395, having a plurality of rows of nozzles configured to extend, in use, across at least part of a printable pagewidth, the nozzles in each row being grouped into at least first and second fire groups, the printhead module being configured to sequentially fire, for each row, the nozzles of each fire group, such that each nozzle in the sequence from each fire group is fired simultaneously with respective corresponding nozzles in the sequence in the other fire groups, wherein the nozzles are fired row by row such that the nozzles of each row are all fired before the nozzles of each subsequent row.

1444. A printhead module according to claim 1395, comprising at least first and second rows configured to print ink of a similar type or color, at least some nozzles in the first row being aligned with respective corresponding nozzles in the second row in a direction of intended media travel relative to the printhead, the printhead module being configurable such that the nozzles in the first and second pairs of rows are fired such that some dots output to print media are printed to by nozzles from the first pair of rows and at least some other dots output to print media are printed to by nozzles from the second pair of rows.

1445. A printhead module according to claim 1395, in communication with a printer controller for providing data to a printhead module that includes:
at least one row of print nozzles;
at least first and second shift registers for shifting in dot data supplied from a data source, wherein each shift register feeds dot data to a group of nozzles, and wherein each of the groups of the nozzles is interleaved with at least one of the other groups of the nozzles.

1446. A printhead module according to claim 1395, comprising a plurality of rows, each of the rows comprising a plurality of nozzles for ejecting ink, wherein the printhead module includes at least first and second rows configured to print ink of a similar type or color, and being configured such that, in the event a nozzle in the first row is faulty, a corresponding nozzle in the second row prints an ink dot at a position on print media at or adjacent a position where the faulty nozzle would otherwise have printed it.

1447. A printhead module according to claim 1414, further including a logic circuit accepting as inputs a masking signal and the thermal signal corresponding to the nozzle for which the dot data is intended, the logic circuit outputting the thermal signal to the input of the AND circuit in reliance on a value of the masking signal.

1448. A printhead module according to claim 1447, wherein the value of the masking signal enables masking of the thermal signal for at least one nozzle position, including the nozzle for which the current dot data is intended.

1449. A printhead module according to claim 1447, wherein the value of the masking signal enables masking of the thermal signal for a plurality of nozzle positions corresponding to a region of the printhead associated the nozzle for which the current dot data is intended.

1450. A printhead module according to claim 1447, wherein the value of the masking signal enables masking of the thermal signal for all of the nozzle positions of the printhead.

1451. A printhead module comprising a plurality of rows, each of the rows comprising a plurality of nozzles for ejecting ink, wherein the printhead module includes at least first and second rows configured to print ink of a similar type or color, and being configured such that, in the event a nozzle in the first row is faulty, a corresponding nozzle in the second row prints an ink dot at a position on print media at or adjacent a position where the faulty nozzle would otherwise have printed it.

1452. A printhead module according to claim 1451, wherein each nozzle in the first row is paired with a nozzle in the second row, such that each pair of nozzles is aligned in an intended direction of print media travel relative to the printhead module.

1453. A printhead module according to claim 1452, including a plurality of sets of the first and second rows.

1454. A printhead module according to claim 1453, wherein each of the sets of the first and second rows is configured to print in a single color or ink type.

1455. A printhead module according to claim 1451, wherein each of the rows includes an odd and an even sub-row, the odd and even sub-rows being offset with respect to each other in a direction of print media travel relative to the printhead in use.

1456. A printhead module according to claim 1455, wherein the odd and even sub-rows are transversely offset with respect to each other.

1457. A printhead comprising a plurality of printhead modules according to claim 1452.

1458. A printhead comprising a plurality of printhead modules according to claim 1454.

1459. A printhead according to claim 1457, the printhead being a pagewidth printhead.

1460. A printhead module according to claim 1451, configured to receive dot data to which a method of at least partially compensating for errors in ink dot placement by at least one of a plurality of nozzles due to erroneous rotational displacement of a printhead module relative to a carrier has been applied, the nozzles being disposed on the printhead module, the method comprising the steps of:
determining the rotational displacement;
determining at least one correction factor that at least partially compensates for the ink dot displacement; and using the correction factor to alter the output of the ink dots to at least partially compensate for the rotational displacement.

1461. A printhead module according to claim 1451, configured to receive dot data to which a method of expelling ink has been applied, the method being applied to a printhead module including at least one row that comprises a plurality of adjacent sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, the method comprising providing, for each set of nozzles, a fire signal in accordance with the sequence: [nozzle position 1, nozzle position n, nozzle position 2, nozzle position (n-1), ... , nozzle position x], wherein nozzle position x is at or adjacent the centre of the set of nozzles.

1462. A printhead module according to claim 1451, configured to receive dot data to which a method of expelling ink has been applied, the method being applied to a printhead module including at least one row that comprises a plurality of sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, the method comprising the steps of:
(a). providing a fire signal to nozzles at a first and nth position in each set of nozzles;
(b). providing a fire signal to the next inward pair of nozzles in each set;
(c). in the event n is an even number, repeating step (b) until all of the nozzles in each set has been fired; and (d). in the event n is an odd number, repeating step (b) until all of the nozzles but a central nozzle in each set have been fired, and then firing the central nozzle.

1463. A printhead module according to claim 1451, having been manufactured in accordance with a method of manufacturing a plurality of printhead modules, at least some of which are capable of being combined in pairs to form bilithic pagewidth printheads, the method comprising the step of laying out each of the plurality of printhead modules on a wafer substrate, wherein at least one of the printhead modules is right-handed and at least another is left-handed.

1464. A printhead module according to claim 1451, including:
at least one row of print nozzles;
at least two shift registers for shifting in dot data supplied from a data source to each of the at least one rows, wherein each print nozzle obtains dot data to be fired from an element of one of the shift registers.

1465. A printhead module according to claim 1451, installed in a printer comprising:
a printhead comprising at least the first elongate printhead module, the at least one printhead module including at least one row of print nozzles for expelling ink; and at least first and second printer controllers configured to receive print data and process the print data to output dot data to the printhead, wherein the first and second printer controllers are connected to a common input of the printhead.

1466. A printhead module according to claim 1451, installed in a printer comprising:
a printhead comprising first and second elongate printhead modules, the printhead modules being parallel to each other and being disposed end to end on either side of a join region;
at least first and second printer controllers configured to receive print data and process the print data to output dot data to the printhead, wherein the first printer controller outputs dot data only to the first printhead module and the second printer controller outputs dot data only to the second printhead module, wherein the printhead modules are configured such that no dot data passes between them.

1467. A printhead module according to claim 1451, installed in a printer comprising:
a printhead comprising first and second elongate printhead modules, the printhead modules being parallel to each other and being disposed end to end on either side of a join region, wherein the first printhead module is longer than the second printhead module;
at least first and second printer controllers configured to receive print data and process the print data to output dot data to the printhead, wherein: the first printer controller outputs dot data to both the first printhead module and the second printhead module; and the second printer controller outputs dot data only to the second printhead module.

1468. A printhead module according to claim 1451, installed in a printer comprising:
a printhead comprising first and second elongate printhead modules, the printhead modules being parallel to each other and being disposed end to end on either side of a join region, wherein the first printhead module is longer than the second printhead module;
at least first and second printer controllers configured to receive print data and process the print data to output dot data for the printhead, wherein: the first printer controller outputs dot data to both the first printhead module and the second controller, and the second printer controller outputs dot data to the second printhead module, wherein the dot data output by the second printer controller includes dot data it generates and at least some of the dot data received from the first printer controller.

1469. A printhead module according to claim 1451, in communication with a printer controller for supplying dot data to at least one printhead module and at least partially compensating for errors in ink dot placement by at least one of a plurality of nozzles on the printhead module due to erroneous rotational displacement of the printhead module relative to a carrier, the printer being configured to:
access a correction factor associated with the at least one printhead module;
determine an order in which at least some of the dot data is supplied to at least one of the at least one printhead modules, the order being determined at least partly on the basis of the correction factor, thereby to at least partially compensate for the rotational displacement; and supply the dot data to the printhead module.

1470. A printhead module according to claim 1451, in communication with a printer controller for supplying dot data to a printhead module having a plurality of nozzles for expelling ink, the printhead module including a plurality of thermal sensors, each of the thermal sensors being configured to respond to a temperature at or adjacent at least one of the nozzles, the printer controller being configured to modify operation of at least some of the nozzles in response to the temperature rising above a first threshold.

1471. A printhead module according to claim 1451, in communication with a printer controller for controlling a printhead comprising at least one monolithic printhead module, the at least one printhead module having a plurality of rows of nozzles configured to extend, in use, across at least part of a printable pagewidth of the printhead, the nozzles in each row being grouped into at least first and second fire groups, the printhead module being configured to sequentially fire, for each row, the nozzles of each fire group, such that each nozzle in the sequence from each fire group is fired simultaneously with respective corresponding nozzles in the sequence in the other fire groups, wherein the nozzles are fired row by row such that the nozzles of each row are all fired before the nozzles of each subsequent row, wherein the printer controller is configured to provide one or more control signals that control the order of firing of the nozzles.

1472. A printhead module according to claim 1451, in communication with a printer controller for outputting to a printhead module:
dot data to be printed with at least two different inks; and control data for controlling printing of the dot data;
the printer controller including at least one communication output, each or the communication output being configured to output at least some of the control data and at least some of the dot data for the at least two inks.

1473. A printhead module according to claim 1451, including at least one row of printhead nozzles, at least one row including at least one displaced row portion, the displacement of the row portion including a component in a direction normal to that of a pagewidth to be printed.

1474. A printhead module according to claim 1451, in communication with a printer controller for supplying print data to at least one printhead module capable of printing a maximum of n of channels of print data, the at least one printhead module being configurable into:
a first mode, in which the printhead module is configured to receive data for a first number of the channels; and a second mode, in which the printhead module is configured to receive print data for a second number of the channels, wherein the first number is greater than the second number;
wherein the printer controller is selectively configurable to supply dot data for the first and second modes.

1475. A printhead module according to claim 1451, in communication with a printer controller for supplying data to a printhead comprising a plurality of printhead modules, the printhead being wider than a reticle step used in forming the modules, the printhead comprising at least two types of the modules, wherein each type is determined by its geometric shape in plan.

1476. A printhead module according to claim 1451, used in conjunction with a printer controller for supplying one or more control signals to a printhead module, the printhead module including at least one row that comprises a plurality of sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, such that:
(a). a fire signal is provided to nozzles at a first and nth position in each set of nozzles;
(b). a fire signal is provided to the next inward pair of nozzles in each set;
(c). in the event n is an even number, step (b) is repeated until all of the nozzles in each set has been fired;
and (d). in the event n is an odd number, step (b) is repeated until all of the nozzles but a central nozzle in each set have been fired, and then the central nozzle is fired.

1477. A printhead module according to claim 1451, used in conjunction with a printer controller for supplying one or more control signals to a printhead module, the printhead module including at least one row that comprises a plurality of adjacent sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, the method comprising providing, for each set of nozzles, a fire signal in accordance with the sequence: [nozzle position 1, nozzle position n, nozzle position 2, nozzle position (n-1), ... , nozzle position x], wherein nozzle position x is at or adjacent the centre of the set of nozzles.

1478. A printhead module according to claim 1451, in communication with a printer controller for supplying dot data to a printhead module comprising at least first and second rows configured to print ink of a similar type or color, at least some nozzles in the first row being aligned with respective corresponding nozzles in the second row in a direction of intended media travel relative to the printhead, the printhead module being configurable such that the nozzles in the first and second pairs of rows are fired such that some dots output to print media are printed to by nozzles from the first pair of rows and at least some other dots output to print media are printed to by nozzles from the second pair of rows, the printer controller being configurable to supply dot data to the printhead module for printing.

1479. A printhead module according to claim 1451, in communication with a printer controller for supplying dot data to at least one printhead module, the at least one printhead module comprising a plurality of rows, each of the rows comprising a plurality of nozzles for ejecting ink, wherein the printhead module includes at least first and second rows configured to print ink of a similar type or color, the printer controller being configured to supply the dot data to the at least one printhead module such that, in the event a nozzle in the first row is faulty, a corresponding nozzle in the second row prints an ink dot at a position on print media at or adjacent a position where the faulty nozzle would otherwise have printed it.

1480. A printhead module according to claim 1451, in communication with a printer controller for receiving first data and manipulating the first data to produce dot data to be printed, the print controller including at least two serial outputs for supplying the dot data to at least one printhead.

1481. A printhead module according to claim 1451, including:
at least one row of print nozzles;
at least first and second shift registers for shifting in dot data supplied from a data source, wherein each shift register feeds dot data to a group of nozzles, and wherein each of the groups of the nozzles is interleaved with at least one of the other groups of the nozzles.

1482. A printhead module according to claim 1451 being capable of printing a maximum of n of channels of print data, the printhead being configurable into:
a first mode, in which the printhead is configured to receive print data for a first number of the channels; and a second mode, in which the printhead is configured to receive print data for a second number of the channels, wherein the first number is greater than the second number.

1483. A printhead comprising a plurality of printhead modules according to claim 1451, the printhead being wider than a reticle step used in forming the modules, the printhead comprising at least two types of the modules, wherein each type is determined by its geometric shape in plan.

1484. A printhead module according to claim 1451, including at least one row that comprises a plurality of sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, such that, for each set of nozzles, a fire signal is provided in accordance with the sequence: [nozzle position 1, nozzle position n, nozzle position 2, nozzle position (n-1), ... , nozzle position x], wherein nozzle position x is at or adjacent the centre of the set of nozzles.

1485. A printhead module according to claim 1451, including at least one row that comprises a plurality of adjacent sets of n adjacent nozzles, each of the nozzles being configured to expel the ink in response to a fire signal, the printhead being configured to output ink from nozzles at a first and nth position in each set of nozzles, and then each next inward pair of nozzles in each set, until:
in the event n is an even number, all of the nozzles in each set has been fired; and in the event n is an odd number, all of the nozzles but a central nozzle in each set have been fired, and then to fire the central nozzle.

1486. A printhead module according to claim 1451, for receiving dot data to be printed using at least two different inks and control data for controlling printing of the dot data, the printhead module including a communication input for receiving the dot data for the at least two colors and the control data.

1487. A printhead module according to claim 1451, including at least one row of printhead nozzles, at least one row including at least one displaced row portion, the displacement of the row portion including a component in a direction normal to that of a pagewidth to be printed.

1488. A printhead module according to claim 1451, having a plurality of rows of nozzles configured to extend, in use, across at least part of a printable pagewidth, the nozzles in each row being grouped into at least first and second fire groups, the printhead module being configured to sequentially fire, for each row, the nozzles of each fire group, such that each nozzle in the sequence from each fire group is fired simultaneously with respective corresponding nozzles in the sequence in the other fire groups, wherein the nozzles are fired row by row such that the nozzles of each row are all fired before the nozzles of each subsequent row.

1489. A printhead module according to claim 1451, comprising at least first and second rows configured to print ink of a similar type or color, at least some nozzles in the first row being aligned with respective corresponding nozzles in the second row in a direction of intended media travel relative to the printhead, the printhead module being configurable such that the nozzles in the first and second pairs of rows are fired such that some dots output to print media are printed to by nozzles from the first pair of rows and at least some other dots output to print media are printed to by nozzles from the second pair of rows.

1490. A printhead module according to claim 1451, in communication with a printer controller for providing data to a printhead module that includes:
at least one row of print nozzles;
at least first and second shift registers for shifting in dot data supplied from a data source, wherein each shift register feeds dot data to a group of nozzles, and wherein each of the groups of the nozzles is interleaved with at least one of the other groups of the nozzles.

1491. A printhead module according to claim 1451, having a plurality of nozzles for expelling ink, the printhead module including a plurality of thermal sensors, each of the thermal sensors being configured to respond to a temperature at or adjacent at least one of the nozzles, the printhead module being configured to modify operation of the nozzles in response to the temperature rising above a first threshold.

1492. A first entity configured to authenticate a digital signature supplied by a second entity, wherein one of the entities includes a base key and the other of the entities includes a variant key and a bit-pattern, the variant key being based on the result of applying a one way function to the base key and the bit-pattern, the digital signature having been generated by the second entity using its key to digitally signing at least part of data to be authenticated, the first entity being configured to:
(a). receive the digital signature from the second entity;
(b). receive the data; and (c). authenticate the digital signature based on the received data and the first entity's key.

1493. A first entity according to claim 1492, including the base key, the first entity being configured to receive, from the second entity, the bit-pattern, wherein (c) includes:
generating the variant key from the bit-pattern and the base key; and authenticating the digital signature using the generated variant key.

1494. A first entity according to claim 1493, the first entity storing information, wherein the data is indicative of a request to be performed on the information.

1495. A first entity according to claim 1494, wherein the information is a value.

1496. A first entity according to claim 1493, wherein the data is indicative of a read instruction.

1497. A first entity according to claim 1493, wherein the data is indicate of a write instruction, the data being indicative of new information to be written.

1498. A first entity according to claim 1493, wherein the data is indicative of a function to be applied to the information.

1499. A first entity according to claim 1498, wherein the function is a decrement or increment function.

1500. A first entity according to claim 1493, wherein the data is indicative of a value stored in the second entity.

1501. A first entity according to claim 1493, the first entity being configured to send a request to the second entity, the data being returned in response to the request.

1502. A first entity according to claim 1501, wherein the data is indicative of a value stored in the second entity.

1503. A first entity according to claim 1501, the first entity being configured to digitally sign at least some of the request with the base key.

1504. A first entity according to claim 1492, wherein the first entity has the base key.

1505. A first entity according to claim 1503, the first entity storing information, wherein the data is indicative of a request to be performed on the information.

1506. A first entity according to claim 1504, wherein the information is a value.

1507. A first entity according to claim 1503, wherein the data is indicative of a read instruction.

1508. A first entity according to claim 1503, wherein the data is indicate of a write instruction, the data being indicative of new information to be written.

1509. A first entity according to claim 1503, wherein the data is indicative of a function to be applied to the information.

1510. A first entity according to claim 1508, wherein the function is a decrement or increment function.

1511. A first entity according to claim 1503, wherein the data is indicative of a value stored in the second entity.

1512. A first entity according to claim 1510,the first entity being configured to send a read request to the second entity, the data being returned in response to the request.

1513. A first entity according to claim 1511,wherein the data is indicative of a value stored in the second entity.

1514. A first entity according to claim 1511,the first entity being configured to digitally sign at least some of the request with the base key.

1515. A first entity according to claim 1492,including:
a first bit-pattern a non-volatile memory storing resource data, a first base key for use with at least a first variant key;
a second variant key for use with a second base key, the second variant key being the result of a one way function applied to: the second base key; and the first bit-pattern or a modified bit-pattern based on the first bit-pattern.

1516. A first entity according to claim 1492,configured for use in a method of enabling or disabling a verification process of a first entity in response to a predetermined event, the first entity having at least one associated bit-pattern and at least one variant key, each of the variant keys having been generated by applying a one way function to: a base key; and one or more of the at least one bit-patterns, respectively; or one or more alternative bit patterns, each of the alternative bit-patterns being based on one or the at least one bit-patterns, the method including the method including:
(a). determining that the predetermined event has happened; and (b). enabling or disabling at least one of the first variant keys in response the predetermined event.

1517. A first entity according to claim 1492,for use in a system for enabling authenticated communication between a first entity and at least one other entity, the system including a second entity, wherein:
the first entity and the second entity share transport keys; and the second entity includes at least one authentication key configured to be transported from the second entity to the first entity using the transport keys, the authentication key being usable to enable the authenticated communication by the first entity.

1518. A first entity according to claim 1492,configured for use in a method of storing a first bit-pattern in non--volatile memory of a device, the method comprising:

(a). applying a one way function to a second bit-pattern associated with the device, thereby to generate a first result;
(b). applying a second function to the first result and the first bit-pattem, thereby to generate a second result and (c). storing the second result in the memory, thereby indirectly storing the first bit-pattern.

1519. A first entity according to claim 1492,configured for use in a method of storing a bit-pattern in each of a plurality of devices, each of the devices having a memory, the method comprising, for each device:
(a). determining a first memory location; and (b). storing the bit-pattern at the first memory location; wherein the first memory locations are different in at least a plurality of the respective devices.

1520. A first entity according to claim 1492,configured for use in a method of storing at least one functionally identical code segment in each of a plurality of devices, each of the devices having a memory, the method comprising, for each device:
(a). determining a first memory location; and (b). storing a first of the at least one code segments in the memory at the first memory location; wherein the first memory location is different in at least a plurality of the respective devices.

1521. A first entity according to claim 1492,configured for implementing a method for providing a sequence of nonces (R0, R1, R2, ... ) commencing with a current seed of a sequence of seeds (x1, x2, x3,...), the method comprising:
(a). applying a one-way function to the current seed, thereby to generate a current nonce; (b) outputting the current nonce;
(b). using the current seed to generate a next seed in a sequence of seeds, the seed so generated becoming the current seed; and (c). repeating steps (a) to (c) as required to generate further nonces in the sequence of nonces.

1522. A first entity according to claim 1492,configured for implementing a method of storing multiple first bit--patterns in non-volatile memory of a device, the method comprising, for each of the first bit-patterns to be stored:
(a). applying a one way function to a third bit pattern based on a second bit-pattern associated with the device, thereby to generate a first result;
(b). applying a second function to the first result and the first bit-pattern, thereby to generate a second result;
and (c). storing the second result in the memory, thereby indirectly storing the first bit-pattem;wherein the third bit-patterns used for the respective first bit patterns are relatively unique compared to each other.

1523. A first entity including:
a first bit-pattern a non-volatile memory storing resource data, a first base key for use with at least a first variant key;
a second variant key for use with a second base key, the second variant key being the result of a one way function, applied to: the second base key; and the first bit-pattern or a modified bit-pattern based on the first bit-pattern.

1524. A first entity according to claim 1523,wherein the first variant key is stored in a second entity.

1525. A first entity according to claim 1523,wherein the second base key is stored in a third entity.

1526. A first entity according to claim 1523,configured to receive a request from any of a plurality of second entities, the request being indicative of at least one operation to be performed on the resource data, each of the second entities having an associated bit-pattern and one of the first variant keys, the first variant key in each of second entities being based on the result of applying a one way function to the first base key and the associated bit-pattern of that second entity, the first entity being configured to:
(a). receive the request from one of the second entities;
(b). perform the at least one operation in the request, thereby to generate a response;
(c). use the first base key to digitally sign at least part of the response, thereby to generate a digital signature;
and (d). send the response and the digital signature to the second entity from which the request was received, such that the second entity can verify the at least part of the response using its variant key.

1527. A first entity according to claim 1526,configured to, prior to (b), receive the associated bit-pattern from the second entity that makes the request in (a), wherein (c) includes:
(i) using the first base key and the associated bit-pattern received from the second entity to generate the first variant key of the second entity making the request in (a); and (ii) using the first variant key generated in (i) to perform the signing of at least part of the response the response.

1528. A first entity according to claim 1523,configured to receive a request from any of one or more third entities, the request being indicative of at least one operation to be performed on the resource data, each of the one or more third entities having the second base key, the first entity being configured to:
(a). receive the request from the one of the third entities;
(b). perform the at least one operation in the request, thereby to generate a response;
(c). use the second variant key to digitally sign at least part of the response, thereby to generate a digital signature; and (d). send the response and the digital signature to the third entity from which the request was received, such that the third entity can verify the at least part of the response using its base key.

1529. A first entity according to claim 1528,configured to send the first bit-pattern to the third entity that makes the request in (e), such that the third entity can:
(i) use the second base key and the bit-pattern received from the first entity to generate the second variant key; and (ii) use the second variant key generated in (i) to perform the verification.

1530. A first entity according to claim 1526,configured to receive a request from any of one or more third entities, the request being indicative of at least one operation to be performed on the resource data, each of the one or more third entities having the second base key, the first entity being configured to:
(a). receive the request from the one of the third entities;
(b). perform the at least one operation in the request, thereby to generate a response;
(c). use the first variant key to digitally sign at least part of at least the response, thereby to generate a digital signature; and (d). send the response and the digital signature to the third entity from which the request was received, such that the third entity can verify at least part of the response using its base key.

1531. A first entity according to claim 1530,configured to send the first bit-pattern the third entity that makes the request in (a), such that the third entity can:
(i) use the second base key and the bit-pattern received from the first entity to generate the second variant key; and (ii) use the second variant key generated in (i) to perform the verification.

1532. A first entity according to claim 1530,wherein the second and third entities have different permissions in relation to the operations they can perform on the resource data, the permissions being defined based which of the first and second base key and variant key combinations is used for the verification.

1533. A first entity according to claim 1532,wherein the first base and variant key combination provides a higher permission to perform an operation on the resource data than the second base key and variant key combination.

1534. A first entity according to claim 1531,wherein the second and third entities have different permissions in relation to the operations they can perform on the resource data, the permissions being defined based which of the first and second base key and variant key combinations is used for the verification.

1535. A first entity according to claim 1534, wherein the first base and variant key combination provides a higher permission to perform an operation on the resource data than the second base key and variant key combination.

1536. A first entity according to claim 1523, configured to receive a request from any of a plurality of second entities, the request being indicative of at least one operation to be performed on the resource data, each of the second entities having an associated bit-pattern and one of the first variant keys, the first variant key in each of second entities being based on the result of applying a one way function to the first base key and the associated bit-pattern of that second entity, the first entity being configured to:
(a). receive the request from one of the second entities;
(b). receive the bit-pattern associated with the entity from which the request was received;
(c). receive a digital signature from the entity from which the request was received, the digital signature having been generated by digitally signing at least part of the request using the variant key;
(d). generate the variant key of the entity from which the request sent, by applying the one way function to the first base key and the received bit pattern; and (e). verify the request by digitally signing at least part of the request using the variant key generated in (d) and comparing the produced signature against the signature received in (d).

1537. A first entity according to claim 1523,configured to receive a request from any of one or more third entities, the request being indicative of at least one operation to be performed on the resource data, each of the one or more third entities having the second base key, the first entity being configured to:
(a). receive the request from the one of the third entities;
(b). receive a digital signature from the third entity from which the request was received, the digital signature having been generated by the third entity signing at least part of the request using the second variant key;
(c). verify the at least part of the request by digitally signing at least part of the request using the second variant key and comparing the produced signature against the signature received in (g).

1538. A first entity according to claim 1537, configured to send the first bit-pattern to the third entity that makes the request in (f), such that the third entity can:
(i) use the second base key and the bit-pattern received from the first entity to generate the second variant key; and (ii) use the second variant key generated in (i) to digitally sign at least part of the request; and (iii) send the request for receipt by the first entity in (a).

1539. A first entity according to claim 1536, configured to receive a request from any of one or more third entities, the request being indicative of at least one operation to be performed on the resource data, each of the one or more third entities having the second base key, the first entity being configured to:

(a). receive the request from the one of the third entities;
(b). receive a digital signature from the third entity from which the request was received, the digital signature having been generated by the third entity signing at least part of the request using the second variant key;
(c). verify the at least par t of the request by digitally signing at least part of the request using the second variant key and comparing the produced signature against the signature received in (g).

1540. A first entity according to claim.1539, wherein the second and third entities have different permissions in relation to the operations they can perform on the resource data, the permissions being defined based which of the first and second base key and variant key combinations is used for the verification.

1541. A first entity according to claim 1540, wherein the first base and variant key combination provides a higher permission to perform an operation on the resource data than the second base key and variant key combination.

1542. A first entity according to claim 1523,wherein the resource data represents a physical property.

1543. A first entity according to claim 1542, wherein the physical property is a remaining amount of a physical resource.

1544. A first entity according to claim 1543, wherein the resource is a consumable resource.

1545. A first entity according to claim 1544, wherein the resource entity is physically attached to a reservoir or magazine that holds the consumable resource.

1546. A first entity according to claim 1545, wherein the resource is a fluid.

1547. A first entity according to claim 1546, wherein the fluid is ink.

1548. A first entity according to claim 1530,wherein the operation includes a read, in which the resource data is read by the entity making the request.

1549. A first entity according to claim 1523,wherein the operation includes write, in which the resource data is modified by the entity making the request.

1550. A first entity according to claim 1523,wherein the operation includes decrementing, in which the resource is decremented by the entity making the request.

1551. A first entity according to claim 1523,wherein the one way function is a hash function.

1552. A first entity according to claim 1551, wherein the one way function is SHA1.

1553. A second entity configured for use with the first entity of claim 1523.

1554. A second entity configured for use with the first entity of claim 1526.

1555. A second entity configured for use with the first entity of claim 1536.

1556. A third entity configured for use with the first entity of claim 1528.

1557. A third entity configured for use with the first entity of claim 1530.

1558. A third entity configured for use with the first entity of claim 1537.

1559. A first entity according to claim 1523,configured to authenticate a digital signature supplied by a second entity, wherein one of the entities includes a base key and the other of the entities includes a variant key and a bit--pattern, the variant key being based on the result of applying a one way function to the base key and the bit--pattem, the digital signature having been generated by the second entity using its key to digitally signing at least part of data to be authenticated, the first entity being configured to:
(a). receive the digital signature from the second entity;
(b). receive the data; and (c). authenticate the digital signature based on the received data and the first entity's key.

1560. A first entity according to claim 1523,configured to implement a method of enabling or disabling a verification process of a first entity in response to a predetermined event, the first entity having at least one associated bit pattem and at least one variant key, each of the variant keys having been generated by applying a one way function to: a base key; and one or more of the at least one bit-patterns, respectively; or one or more alternative bit patterns, each of the alternative bit-patterns being based on one or the at least one bit-pattems, the method including the method including:
(a). determining that the predetermined event has happened; and (b). enabling or disabling at least one of the first variant keys in response the predetermined event.

1561. A first entity according to claim 1523,configured for usein a system for enabling authenticated communication between a first entity and at least one other entity, the system including a second entity, wherein:
the first entity and the second entity share transport keys; and the second entity includes at least one authentication key configured to be transported from the second entity to the first entity using the transport keys, the authentication key being usable to enable the authenticated communication by the first entity.

1562. A first entity according to claim 1523,configured to implement a method of storing a first bit-pattern in non-volatile memory of a device, the method comprising:
(a). applying a one way function to a second bit-pattern associated with the device, thereby to generate a first result;
(b). applying a second function to the first result and the first bit-pattern, thereby to generate a second result;
and (c). storing the second result in the memory, thereby indirectly storing the first bit-pattern.

1563. A first entity according to claim 1523,configured to implement a method of storing a bit-pattern in each of a plurality of devices, each of the devices having a memory, the method comprising, for each device:
(a). determining a first memory location; and (b). storing the bit-pattem at the first memory location; wherein the first memory locations are different in at least a plurality of the respective devices.

1564. A first entity according to claim 1523,configured to implement a method of storing at least one functionally identical code segment in each of a plurality of devices, each of the devices having a memory, the method comprising, for each device:
(a). determining a first memory location; and (b). storing a first of the at least one code segments in the memory at the first memory location; wherein the first memory location is different in at least a plurality of the respective devices.

1565. A first entity according to claim 1523,configured to implement a method for providing a sequence of nonces (R0, R1, R2, ... ) commencing with a current seed of a sequence of seeds (x1, x2, x3,...), the method comprising:
(a). applying a one-way function to the current seed, thereby to generate a current nonce; (b) outputting the current nonce;

(b). using the current seed to generate a next seed in a sequence of seeds, the seed so generated becoming the current seed; and (c). repeating steps (a) to (c) as required to generate further nonces in the sequence of nonces.

1566. A first entity according to claim 1523,configured to implement a method of storing multiple first bit--patterns in non-volatile memory of a device, the method comprising, for each of the first bit-patterns to be stored:
(a). applying a one way function to a third bit-pattern based on a second bit-pattern associated with the device, thereby to generate a first result;
(b). applying a second function to the first result and the first bit-pattern, thereby to generate a second result;
and (c). storing the second result in the memory, thereby indirectly storing the first bit-pattern; wherein the third bit-patterns used for the respective first bit-patterns are relatively unique compared to each other.

1567. A method of enabling or disabling a verification process of a first entity in response to a predetermined event, the first entity having at least one associated bit-pattern and at least one variant key, each of the variant keys having been generated by applying a one way function to: a base key; and one or more of the at least one bit--patterns, respectively; or one or more alternative bit patterns, each of the alternative bit-patterns being based on one or the at least one bit-patterns, the method including the method including:
(a). determining that the predetermined event has happened; and (b). enabling or disabling at least one of the first variant keys in response the predetermined event.

1568. A method according to claim 1567, wherein step (a) includes disabling at least one of the variant keys, such that the disabled at least one variant key can no longer be used to digitally sign information in that entity.

1569. A method according to claim 1567, wherein step (a) includes disabling at least one of the variant keys, such that the disabled at least one variant key can no longer be used to verify information signed by one or more respective base keys related to the disabled at least one variant key in that entity.

1570. A method according to claim 1567, wherein the step of disabling the at least one variant key includes modifying a status of a flag associated with that at least one variant key.

1571. A method according to claim 1567, wherein the step of disabling the at least one variant key includes deleting that at least one variant key.

1572. A method according to claim 1567, wherein the step of disabling the at least one variant key includes modifying that at least one variant key

1573. A method according to claim 1567, wherein the event is a predetermined point in time being reached or passed.

1574. A method according to claim 1567, wherein the first entity includes a plurality of the variant keys, the plurality of variant keys being based on the result of a one way function applied to: a respective one of a corresponding plurality of base keys; and one of the at least one bit-patterns or one of the at least one alternative bit-patterns, the method including the steps of:
determining that a predetermined event related to one of the variant keys has happened; and enabling or disabling at least one of the plurality of variant keys with which the predetermined event is associated.

1575. A method according to claim 1567, wherein the plurality of base keys has a corresponding sequence of predetermined events associated with them, the method including the steps of:
(a). determining that one of the predetermined event has happened; and (b). enabling or disabling the variant key in the sequence corresponding to predetermined event that is determined to have happened.

1576. A method according to claim 1575, wherein the variant keys are disabled in the order of the sequence of predetermined events.

1577. A method according to claim 1576, wherein the sequence of events is chronological.

1578. A method according to claim 1577, wherein each of the events includes a time being reached.

1579. A method according to claim 1578, wherein the step of determining that one of the events has happened includes receiving a time from a trusted source.

1580. A method according to claim 1579, wherein the time is a date.

1581. A method according to claim 1580, wherein the date is determined with a resolution of a month.

1582. A method according to claim 1568, wherein the predetermined event includes detection of compromise of one or more of the keys, the method including disabling the one or more variant keys corresponding to the one or more keys that were compromised.

1583. A method according to claim to claim 1568, wherein the predetermined event includes suspect compromise of one or more of the keys, the method including disabling the one or more variant keys corresponding to the one or more keys that were suspected of being compromised.

1584. A method of manufacturing second entities for use in the verification process with the first entity of claim 1567, each of the first entities including at least first and second variant key, the first variant key having been generated by applying a one way function to a first base key and a first bit-pattern, and the second variant key having been generated by applying a one way function to a second base key and a second bit-pattern, the method comprising the steps of:
manufacturing a plurality of second entities for use with the first entities, each of the second entities including at least the first base key; and upon the first variant key being disabled in response to one of the predetermined event, manufacturing a plurality of third entities for use with the first entities, each of the third entities including at least the second base key.

1585. A method according to claim 1567, wherein the first variant key is automatically disabled in response to a predetermined event.

1586. A method according to claim 1585, further including the step of causing the first variant key to be disabled.

1587. A method according to claim 1586, wherein the first variant key is disabled in response to a time being reached.

1588. A method according to claim 1582, wherein at least some of the first entities have one or more further variant keys, each of the respective further variant keys having been generated by applying a one way function to respective further base keys and bit-patterns, each of the variant keys being enabled or disabled in response to respective predetermined events, the method comprising the step of manufacturing a sequence of sets of second entities, each set of the second entities being manufactured such that the variant key corresponding to its base key is enabled for the verification process during the life of that set.

1589. A method according to claim 1588, wherein the predetermined events are selected such that the variant keys corresponding with the base keys of more than one of the sets are enabled at once.

1590. A method according to claim 1567, using a first entity configured to authenticate a digital signature supplied by a second entity, wherein one of the entities includes a base key and the other of the entities includes a variant key and a bit-pattern, the variant key being based on the result of applying a one way function to the base key and the bit-pattern, the digital signature having been generated by the second entity using its key to digitally signing at least part of data to be authenticated, the first entity being configured to:
(a). receive the digital signature from the second entity;
(b). receive the data; and (c). authenticate the digital signature based on the received data and the first entity's key.

1591. A method according to claim 1567, using a first entity including:
a first bit-pattern a non-volatile memory storing resource data, a first base key for use with at least a first variant key;
a second variant key for use with a second base key, the second variant key being the result of a one way function applied to: the second base key; and the first bit-pattern or a modified bit-pattern based on the first bit-pattern.

1592. A method according to claim 1567, using a system for enabling authenticated communication between a first entity and at least one other entity, the system including a second entity, wherein:
the first entity and the second entity share transport keys; and the second entity includes at least one authentication key configured to be transported from the second entity to the first entity using the transport keys, the authentication key being usable to enable the authenticated communication by the first entity.

1593. A method according to claim 1567, including storing a first bit-pattern in non-volatile memory of a device, the method comprising:
(a). applying a one way function to a second bit-pattern associated with the device, thereby to generate a first result;
(b). applying a second function to the first result and the first bit-pattern, thereby to generate a second result;
and (c). storing the second result in the memory, thereby indirectly storing the first bit-pattern.

1594. A method according to claim 1567, including storing a bit-pattern in each of a plurality of devices, each of the devices having a memory, the method comprising, for each device:
(a). determining a first memory location; and (b). storing the bit-pattern at the first memory location; wherein the first memory locations are different in at least a plurality of the respective devices.

1595. A method according to claim 1567, including storing at least one functionally identical code segment in each of a plurality of devices, each of the devices having a memory, the method comprising, for each device:
(a). determining a first memory location; and (b). storing a first of the at least one code segments in the memory at the first memory location; wherein the first memory location is different in at least a plurality of the respective devices.

1596. A method according to claim 1567, including providing a sequence of nonces (R0, R1, R2, ...) commencing with a current seed of a sequence of seeds (x1, x2, x3,...), the method comprising:
(a). applying a one-way function to the current seed, thereby to generate a current nonce; (b) outputting the current nonce;
(b). using the current seed to generate a next seed in a sequence of seeds, the seed so generated becoming the current seed; and (c). repeating steps (a) to (c) as required to generate further nonces in the sequence of nonces.

1597. A method according to claim 1567, including storing multiple first bit-patterns in non-volatile memory of a device, the method comprising, for each of the first bit-patterns to be stored:
(a). applying a one way function to a third bit-pattern based on a second bit-pattern associated with the device, thereby to generate a first result;
(b). applying a second function to the first result and the first bit-pattern, thereby to generate a second result;
and (c). storing the second result in the memory, thereby indirectly storing the first bit-pattern; wherein the third bit-patterns used for the respective first bit-patterns are relatively unique compared to each other.

1598. A system for enabling authenticated communication between a first entity and at least one other entity, the system including a second entity, wherein:
the first entity and the second entity share transport keys; and the second entity includes at least one authentication key configured to be transported from the second entity to the first entity using the transport keys, the authentication key being usable to enable the authenticated communication by the first entity.

1599. A system according to claim 1598, wherein the transport keys include:
a first transport key in the first entity; and a second transport key in the second entity.

1600. A system according to claim 1599, wherein the first and second transport keys are the same.

1601. A system according to claim 1600, wherein the second transport key is a base key and the first transport key is a variant key, the variant key having been generated by applying a one way function to the base key and a first bit-pattern.

1602. A system according to claim 1601, wherein the first bit-pattern is stored in the first entity.

1603. A system according to claim 1600, wherein each of the first and second transport keys is a second bit-pattern stored in the first and second entities during manufacture of the system or its components.

1604. A system according to claim 1603, wherein the second bit-pattern was determined randomly or pseudo-randomly.

1605. A system according to claim 1604, wherein the second bit-pattern was generated using a stochastic process or mechanism.

1606. A system according to claim 1598, wherein the authentication key enables authenticated communication between the first and second entities.

1607. A system according to claim 1606, wherein the authentication key provides the first entity with permission to request performance of at least one operation on at least one value in the second entity.

1608. A system according to claim 1598, wherein the authentication key enables authenticated communication between the first entity and one or more entities other than the second entity.

1609. A system according to claim 1608, wherein the authentication key is a variant key.

1610. A system according to claim 1608, wherein the one or more entities include the base key corresponding to the authentication key.

1611. A plurality of systems, each being in accordance with claim 1609, wherein the variant key in each system is relatively unique compared to the variant keys in the other systems.

1612. A system according to claim 1598, wherein the authentication key is a third bit-pattern that was determined randomly or pseudo-randomly.

1613. A system according to claim 1612, wherein the third bit-pattern was generated using a stochastic process or mechanism.

1614. A system for enabling authenticated communication between a first entity and at least one other entity, the system including a second entity, wherein:
the first entity and the second entity share additional transport keys;
the second entity and each of the at least one other entities share transport keys; and the second entity includes at least one authentication key configured to be transported from the second entity to the first entity using the first transport keys and to each of the at least one other entities using the respective additional shared transport keys, such that the authentication keys, once transported to the first and at least one other entities, enable verified communication therebetween.

1615. A system according to claim 1614, wherein each pair of transport keys is different from the other pairs of transport keys.

1616. A system according to claim 1614, wherein the authentication key is the first transport key.

1617. A system according to claim 1614, wherein the authentication key is the additional transport key for one of the at least one other entities.

1618. A system according to claim 1614, wherein the authentication key is not the same as any of the transport keys.

1619. A system according to claim 1614, wherein the authentication key is a variant key, the variant key having been generated by applying a one way function to a base key and a first bit-pattern.

1620. A system according to claim 1619, wherein the first transport key is a bit-pattern stored in the first and second entities during manufacture of the system or its components.

1621. A system according to claim 1620, wherein the bit-pattern was determined randomly or pseudo-randomly.

1622. A system according to claim 1621, wherein the bit-pattern was generated using a stochastic process or mechanism.

1623. A method of manufacturing a system having at least first and second entities, method comprising the steps of:
providing the first and second entities with transport keys; and providing the second entity with at least one authentication key;

the system being configured to enable transport of the at least one authentication key from the second entity to the first entity using the transport keys, the authentication key being usable to enable the authenticated communication by the first entity.

1624. A method according to claim 1623, wherein the transport keys include:
a first transport key in the first entity; and a second transport key in the second entity.

1625. A method according to claim 1624, wherein the first and second transport keys are the same.

1626. A method according to claim 1625, wherein the second transport key is a base key and the first transport key is a variant key, the variant key having been generated by applying a one way function to the base key and a first bit-pattern.

1627. A method according to claim 1626, wherein the first bit-pattern is stored in the first entity.

1628. A method according to claim 1625, wherein each of the first and second transport keys is a second bit-pattern stored in the first and second entities during manufacture of the system or its components.

1629. A method according to claim 1628, wherein the second bit-pattern was determined randomly or pseudo-randomly.

1630. A method according to claim 1629, wherein the second bit pattern was generated using a stochastic process or mechanism.

1631. A method according to claim 1623, wherein the authentication key enables authenticated communication between the first and second entities.

1632. A method according to claim 1623, wherein the authentication key enables authenticated communication between the first entity and one or more entities other than the second entity.

1633. A method according to claim 1623, wherein the authentication key is a third bit-pattern that was determined randomly or pseudo-randomly.

1634. A method according to claim 1633, wherein the third bit-pattern was generated using a stochastic process or mechanism.

1635. A method for enabling authenticated communication between a first entity and at least one other entity in a system including a second entity, wherein:
the first entity and the second entity share first transport keys;
the second entity and each of the at least one other entities share additional transport keys; and the second entity includes at least one authentication key;
the method including the steps of:
transporting the authentication key from the second entity to the first entity using the first transport keys, and to each of the at least one other entities using the respective shared additional transport keys, such that the authentication keys, once transported to the first and at least one other entities, enable verified communication therebetween.

1636. A method according to claim 1635, wherein each pair of transport keys is different from the other pairs of transport keys.

1637. A method according to claim 1635, wherein the authentication key is the first transport key.

1638. A method according to claim 1635, wherein the authentication key is one of the additional transport keys.

1639. A method according to claim 1635, wherein the authentication key is not the same as any of the transport keys.

1640. A method according to claim 1635, wherein the authentication key is a variant key, the variant key having been generated by applying a one way function to a base key and a first bit-pattern.

1641. A method according to claim 1640, wherein the first transport key is a bit-pattern stored in the first and second entities during manufacture of the system or its components.

1642. A method according to claim 1641, wherein bit-pattern was determined randomly or pseudo-randomly.

1643. A method according to claim 1642, wherein the bit-pattern was generated using a stochastic process or mechanism.

1644. A system according to claim 1598, including a first entity configured to authenticate a digital signature supplied by a second entity, wherein one of the entities includes a base key and the other of the entities includes a variant key and a bit-pattern, the variant key being based on the result of applying a one way function to the base key and the bit-pattern, the digital signature having been generated by the second entity using its key to digitally signing at least part of data to be authenticated, the first entity being configured to:

(a). receive the digital signature from the second entity;
(b). receive the data; and (c). authenticate the digital signature based on the received data and the first entity's key.

1645. A system according to claim 1598, including a first entity including:
a first bit-pattern a non-volatile memory storing resource data, a first base key for use with at least a first variant key;
a second variant key for use with a second base key, the second variant key being the result of a one way function applied to: the second base key; and the first bit-pattern or a modified bit-pattern based on the first bit-pattern.

1646. A system according to claim 1598, configured to implement a method of enabling or disabling a verification process of a first entity in response to a predetermined event, the first entity having at least one associated bit-pattern and at least one variant key, each of the variant keys having been generated by applying a one way function to: a base key; and one or more of the at least one bit-patterns, respectively; or one or more alternative bit patterns, each of the alternative bit-patterns being based on one or the at least one bit-patterns, the method including the method including:
(a). determining that the predetermined event has happened; and (b). enabling or disabling at least one of the first variant keys in response the predetermined event.

1647. A system according to claim 1598, configured to implement a method of storing a first bit-pattern in non-volatile memory of a device, the method comprising:
(a). applying a one way function to a second bit-pattern associated with the device, thereby to generate a first result;
(b). applying a second function to the first result and the first bit-pattern, thereby to generate a second result;
and (c). storing the second result in the memory, thereby indirectly storing the first bit-pattern.

1648. A system according to claim 1598, configured to implement a method of storing a bit-pattern in each of a plurality of devices, each of the devices having a memory, the method comprising, for each device:
(a). determining a first memory location; and (b). storing the bit-pattern at the first memory location; wherein the first memory locations are different in at least a plurality of the respective devices.

1649. A system according to claim 1598, configured to implement a method of storing at least one functionally identical code segment in each of a plurality of devices, each of the devices having a memory, the method comprising, for each device:
(a). determining a first memory location; and (b). storing a first of the at least one code segments in the memory at the first memory location;wherein the first memory location is different in at least a plurality of the respective devices.

1650. A system according to claim 1598, configured to implement a method of providing a sequence of nonces (R0, R1, R2, ... ) commencing with a current seed of a sequence of seeds (x1, x2, x3,...), the method comprising:
(a). applying a one-way function to the current seed, thereby to generate a current nonce; (b) outputting the current nonce;
(b). using the current seed to generate a next seed in a sequence of seeds, the seed so generated becoming the current seed; and (c). repeating steps (a) to (c) as required to generate further nonces in the sequence of nonces.

1651. A system according to claim 1598, configured to implement a method of storing multiple first bit-patterns in non-volatile memory of a device, the method comprising, for each of the fust bit-patterns to be stored:
(a). applying a one way function to a third bit-pattern based on a second bit-pattern associated with the device, thereby to generate a first result;
(b). applying a second function to the first result and the first bit-pattern, thereby to generate a second result;
and (d). storing the second result in the memory, thereby indirectly storing the first bit-pattern;wherein the third bit-patterns used for the respective first bit-patterns are relatively unique compared to each other.

1652. A method of storing a first bit-pattern in non-volatile memory of a device, the method comprising:
(a). applying a one way function to a second bit-pattern associated with the device, thereby to generate a first result;
(b). applying a second function to the first result and the first bit-pattern, thereby to generate a second result;
and (c). storing the second result in the memory, thereby indirectly storing the first bit-pattern.

1653. A method according to claim 1652, wherein the one way function is more cryptographically secure than the second function.

1654. A method according to claim 1653, wherein the second function is a logical function.

1655. A method according to claim 1654, wherein the logical function is an XOR
function.

1656. A method according to claim 1653, wherein the one way function is a hash function.

1657. A method according to claim 1653, wherein the one way function is SHA1.

1658. A method according to claim 1652, wherein the first bit-pattern is a key.

1659. A method according to claim 1652, further including the step of storing one or more code segments in the memory, the code segments being configured to run on a processor of the device, thereby enabling the device to:
apply the one way function to the second bit-pattern, thereby to generate the first result;
apply a third function to the first result and the second result, thereby to generate the first bit-pattern;wherein the third function is the inverse of the second function.

1660. A method according to claim 1659, wherein the third function and the second function are the same.

1661. A method according to claim 1652, wherein the second bit-pattern was generated randomly or pseudo-randomly.

1662. A method according to claim 1652, the method further including the step, performed prior to step (a), of determining the second bit-pattern.

1663. A method according to claim 1662, wherein determining the second bit-pattern includes generating the second bit-pattern randomly or pseudo-randomly.

1664. A method according to claim 1662, wherein determining the second bit-pattern includes generating the second bit-pattern based on a stochastic process or mechanism.

1665. A method according to claim 1662, wherein determining the second bit-pattern includes selecting the second-bit pattern from an existing list or sequence of second bit-patterns.

1666. A method of storing a first bit-pattern in non-volatile memory of each of a plurality of devices, the method comprising, for each of the devices:
(a). applying a one way function to a second bit-pattern associated with the device, thereby to generate a first result;
(b). applying a second function to the first result and the first bit-pattern, thereby to generate a second result;
and (c). storing the second result in the non-volatile memory, thereby indirectly storing the first bit-pattern;wherein the second bit-patterns of the respective devices are relatively unique with respect to each other.

1667. A method according to claim 1666, wherein the one way function is more cryptographically secure than the second function.

1668. A method according to claim 1667, wherein the second function is a logical function.

1669. A method according to claim 1668, wherein the logical function is an XOR
function.

1670. A method according to claim 1667, wherein the one way function is a hash function.

1671. A method according to claim 1667, wherein the one way function is SHA1.

1672. A method according to claim 1666, wherein the first bit-pattern is a key.

1673. A method according to claim 1666, wherein step (c) comprises, for each device:
(a). determining a first memory location; and (b). storing the second result at the first memory location; wherein the first memory locations are different in at least a plurality of the respective devices.

1674. A method according to claim 1673, wherein step (d) includes randomly selecting the first memory location.

1675. A method according to claim 1674, wherein step (a) includes selecting the first memory location based on a stochastic process or mechanism.

1676. A method according to claim 1673, wherein step (a) includes selecting the fust memory location from an existing list or sequence of memory locations.

1677. A method according to claim 1666, further including the step of storing one or more code segments in the device, the code segments being configured to run on a processor of the device, thereby enabling the device to:
apply the one way function to the second bit-pattern, thereby to generate the first result and apply a third function to the first result and the second result, thereby to generate the first bit-pattern; wherein the third function is the inverse of the second function.

1678. 27, A method according to claim 1677, wherein the third function and the second function are the same.

1679. A method according to claim 1677, wherein the second bit-patterns have characteristics associated with random numbers.

1680. A method according to claim 1679, wherein the second bit-pattern was generated randomly or pseudo-randomly.

1681. A method according to claim 1679, the method further including the step, performed prior to step (a), of determining the second bit-pattern.

1682. A method according to claim 1681, wherein determining the second bit-pattern includes generating the second bit-pattern randomly or pseudo-randomly.

1683. A method according to claim 1681, wherein determining the second bit-pattern includes generating the second bit-pattern based on a stochastic process or mechanism.

1684. A device manufactured in accordance with the method of claim 1652.

1685. A device manufactured in accordance with the method of claim 1659.

1686. A device manufactured in accordance with the method of claim 1666.

1687. A device manufactured in accordance with the method of claim 1677.

1688. A device having an associated second bit-pattern, and non-volatile memory, the non-volatile memory indirectly storing a first bit-pattem in the form of a second result, the second result being generated by:
(a). applying a one way function to the second bit-pattern, thereby to generate a first result; and (b). applying a second function to the first result and the first bit-pattem, thereby to generate the second result.

1689. A device according to claim 1688, further including a processor, the processor being configured to run one or more code segments that:
apply the one way function to the second bit pattern, thereby to generate the first result; and apply a third function to the first result and the second result, the third function being the inverse of the second function, thereby to generate the first bit-pattern.

1690. A device according to claim 1689, wherein the third function and the second function are the same.

1691. A device according to claim 1689, wherein the one or more code segments, when run on the processor, use the first bit-pattern in a cryptographic process.

1692. A device according to claim 1691, wherein the cryptographic process is digital signing.

1693. A device according to claim 1688, wherein the one way function is more cryptographically secure than the second function.

1694. A device according to claim 1688, wherein the second function is a logical function.

1695. A device according to claim 1688, wherein the logical function is an XOR
function.

1696. A device according to claim 1688, wherein the one way function is a hash function.

1697. A device according to claim 1688, wherein the one way function is SHA1.

1698. A device according to claim 1688, wherein the first bit-pattern is a key.

1699. A device according to claim 1688, wherein the second bit-pattern was generated randomly or pseudo-randomly.

1700. A device according to claim 1699, wherein the second bit-pattem was generated using a stochastic process or mechanism.

1701. A method according to claim 1652, implemented in a first entity configured to authenticate a digital signature supplied by a second entity, wherein one of the entities includes a base key and the other of the entities includes a variant key and a bit-pattern, the variant key being based on the result of applying a one way function to the base key and the bit-pattern, the digital signature having been generated by the second entity using its key to digitally signing at least part of data to be authenticated, the first entity being configured to:
(a). receive the digital signature from the second entity;
(b). receive the data; and (c). authenticate the digital signature based on the received data and the first entity's key.

1702. A method according to claim 1652, implemented in a first entity including:
a first bit-pattern a non-volatile memory storing resource data, a first base key for use with at least a first variant key;
a second variant key for use with a second base key, the second variant key being the result of a one way function applied to: the second base key; and the first bit-pattern or a modified bit-pattern based on the first bit-pattern.

1703. A method according to claim 1652, for enabling or disabling a verification process of a first entity in response to a predetermined event, the first entity having at least one associated bit-pattern and at least one variant key, each of the variant keys having been generated by applying a one way function to: a base key; and one or more of the at least one bit-patterns, respectively; or one or more alternative bit patterns, each of the alternative bit-patterns being based on one or the at least one bit-pattems, the method including the method including:
(a). determining that the predetermined event has happened; and (b). enabling or disabling at least one of the first variant keys in response the predetermined event.

1704. A method according to claim 1652, implemented in a system for enabling authenticated communication between a first entity and at least one other entity, the system including a second entity, wherein:
the first entity and the second entity share transport keys; and the second entity includes at least one authentication key configured to be transported from the second entity to the first entity using the transport keys, the authentication key being usable to enable the authenticated communication by the first entity.

1705. A method according to claim 1652, for storing a bit-pattem in each of a plurality of devices, each of the devices having a memory, the method comprising, for each device:
(a). determining a first memory location; and (b). storing the bit-pattern at the first memory location;wherein the first memory locations are different in at least a plurality of the respective devices.

1706. A method according to claim 1652, for storing at least one functionally identical code segment in each of a plurality of devices, each of the devices having a memory, the method comprising, for each device:
(a). determining a first memory location; and (b). storing a first of the at least one code segments in the memory at the first memory location; wherein the first memory location is different in at least a plurality of the respective devices.

1707. A method according to claim 1652, for providing a sequence of nonces (R0, R1, R2, ... ) commencing with a current seed of a sequence of seeds (x1, x2, x3,...), the method comprising:
(a). applying a one-way function to the current seed, thereby to generate a current nonce; (b) outputting the current nonce;

(b). using the current seed to generate a next seed in a sequence of seeds, the seed so generated becoming the current seed; and (c). repeating steps (a) to (c) as required to generate further nonces in the sequence of nonces.

1708. A method according to claim 1652, for storing multiple first bit-patterns in non-volatile memory of a device, the method comprising, for each of the first bit-patterns to be stored:
(a). applying a one way function to a third bit-pattern based on a second bit-pattern associated with the device, thereby to generate a first result;
(b). applying a second function to the first result and the first bit-pattern, thereby to generate a second result;
and (c). storing the second result in the memory, thereby indirectly storing the first bit-pattern; wherein the third bit-patterns used for the respective first bit-patterns are relatively unique compared to each other.

1709. A method of storing a bit-pattern in each of a plurality of devices, each of the devices having a memory, the method comprising, for each device:
(a). determining a first memory location; and (b). storing the bit-pattern at the first memory location;wherein the first memory locations are different in at least a plurality of the respective devices.

1710. A method according to claim 1709, wherein step (a) includes randomly selecting the first memory location.

1711. A method according to claim 1710, wherein step (a) includes selecting the first memory location based on a stochastic process or mechanism.

1712. A method according to claim 1709, wherein step (a) includes selecting the first memory location from an existing list or sequence of memory locations.

1713. A method according to claim 1709, wherein the memory is non-volatile memory.

1714. A method according to claim 1713, the method further comprising storing one or more code segments in the memory of each device, the one or more code segments including data indicative of the first memory location at which the bit-pattern is stored on that device.

1715. A method according to claim 1709, wherein the first memory locations of the devices are selected such that, from device to device, there is no overlap of the positions of at least some of the bits, bytes or characters of the devices' respective bit-pattern.

1716. A method according to claim 1709, wherein the first memory locations of the devices are selected such that, from device to device, positions of at least some of the bits, bytes or characters of the devices' respective bit-patterns overlap.

1717. A method according to claim 1709, wherein the first memory locations of the devices are selected such that, from device to device, bit, byte or character positions of the devices' respective bit-patterns are shuffled, rotated or otherwise ordered differently.

1718. A method according to claim 1716, wherein the first memory locations of the devices are selected such that, from device to device, bit, byte or character positions of the devices' respective bit-patterns are shuffled, rotated or otherwise ordered differently.

1719. A method according to claim 1709, comprising:
applying a function to the first bit pattern and a second bit pattern, thereby to generate a result; and storing the result in the first memory location, thereby indirectly storing the first bit pattern.

1720. A method according to claim 1719, wherein the second bit-pattern is stored with the device.

1721. A method according to claim 1720, wherein the second bit-pattern is stored in the device in a non-volatile manner.

1722. A method according to claim 1719, wherein the function is a logical function.

1723. A method according to claim 1722, wherein the logical function is an XOR
function.

1724. A method according to claim 1723, wherein the first bit-pattern is a key.

1725. A method according to claim 1719, wherein the second bit pattern was generated randomly.

1726. A method according to claim 1725, comprising randomly selecting the second bit-pattern.

1727. A method according to claim 1726, comprising selecting the second bit-pattern based on a stochastic process or mechanism.

1728. A method according to claim 1719, comprising selecting the second bit-pattern from an existing list or sequence of bit-patterns.

1729. A method according to claim 1719, wherein the first memory locations of the devices are selected such that, from device to device, there is no overlap of the positions of at least some of the bits, bytes or characters of the devices' respective results.

1730. A method according to claim 1719, wherein the first memory locations of the devices are selected such that, from device to device, positions of at least some of the bits, bytes or characters of the devices' respective results overlap.

1731. A method according to claim 1719, wherein the first memory locations of the devices are selected such that, from device to device, bit, byte or character positions of the devices' respective results are shuffled, rotated or otherwise ordered differently.

1732. A method according to claim 1730, wherein the first memory locations of the devices are selected such that, from device to device, bit, byte or character positions of the devices' respective results are shuffled, rotated or otherwise ordered differently.

1733. A method according to claim 1719, wherein the respective second bit-patterns are stored at a second memory location of each of the respective devices, wherein the second memory locations are different in at least a plurality of the respective devices.

1734. A method according to claim 1733, wherein the second memory locations of the devices are selected such that, from device to device, there is no overlap of the positions of at least some of the bits, bytes or characters of the devices' respective second bit-patterns.

1735. A method according to claim 1733, wherein the second memory locations of the devices are selected such that, from device to device, positions of at least some of the bits, bytes or characters of the devices' respective second bit-patterns overlap.

1736. A method according to claim 1733, wherein the second memory locations of the devices are selected such that, from device to device, bit, byte or character positions of the devices' respective second bit-patterns are shuffled, rotated or otherwise ordered differently.

1737. A method according to claim 1735, wherein the second memory locations of the devices are selected such that, from device to device, bit, byte or character positions of the devices' respectives second bit-patterns are shuffled, rotated or otherwise ordered differently.

1738. A method according to claim 1733, the method further comprising storing one or more code segments in the memory of each device, the one or more code segments including data indicative of the second memory location at which the second bit-pattern is stored on that device.

1739. A method according to claim 1709, further comprising, for each device:
determining a second memory location; and storing, at the second memory location, a result of applying a function to the bit-pattern;wherein the second memory locations are different in at least a plurality of the respective devices.

1740. A method according to claim 1739, wherein the function is a logical operation.

1741. A method according to claim 1739, wherein the function is a bit inversion operation.

1742. A method according to claim 1739, wherein step (a) includes randomly selecting the second memory location.

1743. A method according to claim 1742, wherein step (a) includes selecting the second memory location based on a stochastic process or mechanism.

1744. A method according to claim 1739, wherein step (a) includes selecting the second memory location from an existing list or sequence of memory locations.

1745. A method according to claim 1739, wherein the memory is non-volatile memory.

1746. A method according to claim 1745, the method further comprising storing one or more code segments in the memory of each device, the one or more code segments including data indicative of the second memory location at which the result is stored on that device.

1747. A method according to claim 1746, wherein the second memory locations of the devices are selected such that, from device to device, there is no overlap of the positions of at least some of the bits, bytes or characters of the devices' respective results.

1748. A method according to claim 1746, wherein the second memory locations of the devices are selected such that, from device to device, positions of at least some of the bits, bytes or characters of the devices' respective results overlap.

1749. A method according to claim 1739, wherein the second memory locations of the devices are selected such that, from device to device, bit, byte or character positions of the devices' respective results are shuffled, rotated or otherwise ordered differently.

1750. A method according to claim 1748, wherein the second memory locations of the devices are selected such that, from device to device, bit, byte or character positions of the devices' respective results are shuffled, rotated or otherwise ordered differently.

1751. A device having a bit-pattern stored in it in accordance with the method of claim 1709.

1752. A device having a bit-pattern and a result stored in it in accordance with the method of claim 1719.

1753. A device having a bit-pattern and a result stored in it in accordance with the method of claim 1729.

1754. A plurality of devices having respective bit-patterns stored in them in accordance with the method of claim 1709.

1755. A plurality of devices having respective bit-patterns and results stored in them in accordance with the method of claim 1719.

1756. A plurality of devices having respective bit-patterns and results stored in them in accordance with the method of claim 1729.

1757. A device having a bit-pattern stored in it in accordance with the method of claim 1709.

1758. A device having a bit-pattern and a result stored in it in accordance with the method of claim 1719.

1759. A device having a bit-pattern and a result stored in it in accordance with the method of claim 1729.

1760. A plurality of devices having respective bit patterns stored in them in accordance with the method of claim 1709.

1761. A plurality of devices having a bit-pattern and a result stored in them in accordance with the method of claim 1719.

1762. A plurality of devices having a bit-pattern and a result stored in them in accordance with the method of claim 1729.

1763. A method according to claim 1709, implemented in a first entity configured to authenticate a digital signature supplied by a second entity, wherein one of the entities includes a base key and the other of the entities includes a variant key and a bit-pattern, the variant key being based on the result of applying a one way function to the base key and the bit-pattern, the digital signature having been generated by the second entity using its key to digitally signing at least part of data to be authenticated, the first entity being configured to:
(a). receive the digital signature from the second entity;
(b). receive the data; and (c). authenticate the digital signature based on the received data and the first entity's key.

1764. A method according to claim 1709, implemented in a first entity including:
a first bit pattern a non-volatile memory storing resource data, a first base key for use with at least a first variant key;
a second variant key for use with a second base key, the second variant key being the result of a one way function applied to: the second base key; and the first bit-pattern or a modified bit-pattern based on the first bit-pattern.

1765. A method according to claim 1709, for enabling or disabling a verification process of a fust entity in response to a predetermined event, the first entity having at least one associated bit-pattern and at least one variant key, each of the variant keys having been generated by applying a one way function to: a base key; and one or more of the at least one bit-patterns, respectively; or one or more alternative bit patterns, each of the alternative bit-patterns being based on one or the at least one bit-patterns, the method including the method including:
(a). determining that the predetermined event has happened; and (b). enabling or disabling at least one of the first variant keys in response the predetermined event.

1766. A method according to claim 1709, implemented in a system for enabling authenticated communication between a first entity and at least one other entity, the system including a second entity, wherein:
the first entity and the second entity share transport keys; and the second entity includes at least one authentication key configured to be transported from the second entity to the first entity using the transport keys, the authentication key being usable to enable the authenticated communication by the first entity.

1767. A method according to claim 1709, for storing a first bit-pattern in non-volatile memory of a device, the method comprising:
(a). applying a one way function to a second bit-pattern associated with the device, thereby to generate a first result;

(b). applying a second function to the first result and the first bit-pattern, thereby to generate a second result and (c). storing the second result in the memory, thereby indirectly storing the first bit pattern.

1768. A method according to claim 1709, for storing at least one functionally identical code segment in each of a plurality of devices, each of the devices having a memory, the method comprising, for each device:
(a). determining a first memory location; and (b). storing a first of the at least one code segments in the memory at the first memory location;wherein the first memory location is different in at least a plurality of the respective devices.

1769. A method according to claim 1709, for providing a sequence of nonces (R0, R1, R2, ... ) commencing with a current seed of a sequence of seeds (x1, x2, x3,...), the method comprising:
(a). applying a one-way function to the current seed, thereby to generate a current nonce; (b) outputting the current nonce;
(b). using the current seed to generate a next seed in a sequence of seeds, the seed so generated becoming the current seed; and (c). repeating steps (a) to (c) as required to generate further nonces in the sequence of nonces.

1770. A method according to claim 1709, for storing multiple first bit-patterns in non-volatile memory of a device, the method comprising, for each of the first bit-patterns to be stored:
(a). applying a one way function to a third bit-pattern based on a second bit pattern associated with the device, thereby to generate a first result;
(b). applying a second function to the first result and the first bit-pattern, thereby to generate a second result;
and (c). storing the second result in the memory, thereby indirectly storing the first bit-pattern; wherein the third bit-patterns used for the respective first bit-patterns are relatively unique compared to each other.

1771. A method of storing at least one functionally identical code segment in each of a plurality of devices, each of the devices having a memory, the method comprising, for each device:
(a). determining a first memory location; and (b). storing a first of the at least one code segments in the memory at the first memory location; wherein the first memory location is different in at least a plurality of the respective devices.

1772. A method according to claim 1771, wherein at least one of the code segments in each of the devices includes an initial instruction, the initial instruction being located at an initial instruction location, the initial instruction location being the same in all the devices.

1773. A method according to claim 1772, wherein the initial instruction in each device is indicative of the first memory location of that device.

1774. A method according to claim 1773, wherein the initial instruction is indicative of the first memory location by including an explicit reference to the memory location.

1775. A method according to claim 1774, wherein the initial instruction is indicative of the first memory location by including an implicit reference to the memory location.

1776. A method according to claim 1775, wherein the implicit reference is a pointer to a location at which the address of the first memory location is stored.

1777. A method according to claim 1776, wherein the implicit reference is a pointer to a register that holds the address of the first memory location.

1778. A method according to claim 1771, wherein step (a) includes randomly selecting the first memory location.

1779. A method according to claim 1778, wherein step (a) includes selecting the first memory location based on a stochastic process or mechanism.

1780. A method according to claim 1771, wherein step (a) includes selecting the first memory location from an existing list or sequence of memory locations.

1781. A method according to claim 1771, each device including at least one additional memory location, each of the at least one code segments being located at the first memory location or one of the additional memory locations, wherein each of the code segments includes at least one instruction that is indicative of one of the at least one additional memory locations or of the first memory location, and wherein at least one of the additional memory locations corresponding to one of the code segments is different in at least a plurality of the respective devices.

1782. A method according to claim 1781, wherein the at least one instruction is indicative of the additional or first memory location by including an explicit reference to the memory location.

1783. A method according to claim 1782, wherein the at least one instruction is indicative of the additional or first memory location by including an implicit reference to the memory location.

1784. A method according to claim 1783, wherein the implicit reference is a pointer to a location at which the address of the additional or first memory location is stored.

1785. A method according to claim 1784, wherein the implicit reference is a pointer to a register that holds the address of the additional or first memory location.

1786. A method according to claim 1783, wherein the implicit reference is an index into an address table wherein the address table holds the location of the additional or first memory location.

1787. A method according to claim 1771, wherein the memory is non-volatile memory.

1788. A method according to claim 1781, wherein the memory is non-volatile memory.

1789. A method according to claim 1771, implemented in a first entity configured to authenticate a digital signature supplied by a second entity, wherein one of the entities includes a base key and the other of the entities includes a variant key and a bit pattern, the variant key being based on the result of applying a one way function to the base key and the bit-pattern, the digital signature having been generated by the second entity using its key to digitally signing at least part of data to be authenticated, the first entity being configured to:
(a). receive the digital signature from the second entity;
(b). receive the data; and (c). authenticate the digital signature based on the received data and the first entity's key.

1790. A method according to claim 1771, implemented in a first entity including:
a first bit-pattern a non-volatile memory storing resource data, a first base key for use with at least a first variant key;
a second variant key for use with a second base key, the second variant key being the result of a one way function applied to: the second base key; and the first bit-pattern or a modified bit-pattern based on the first bit-pattern.

1791. A method according to claim 1771, for enabling or disabling a verification process of a first entity in response to a predetermined event, the first entity having at least one associated bit-pattem and at least one variant key, each of the variant keys having been generated by applying a one way function to: a base key; and one or more of the at least one bit-patterns, respectively; or one or more altemative bit patterns, each of the altemative bit-patterns being based on one or the at least one bit-patterns, the method including the method including:
(a). determining that the predetermined event has happened; and (b). enabling or disabling at least one of the first variant keys in response the predetermined event.

1792. A method according to claim 1771, implemented in a system for enabling authenticated communication between a first entity and at least one other entity, the system including a second entity, wherein:
the first entity, and the second entity share transport keys; and the second entity includes at least one authentication key configured to be transported from the second entity to the first entity using the transport keys, the authentication key being usable to enable the authenticated communication by the first entity.

1793. A method according to claim 1771, for storing a first bit-pattern in non-volatile memory of a device, the method comprising:
(a). applying a one way function to a second bit-pattern associated with the device, thereby to generate a first result;
(b). applying a second function to the first result and the fust bit-pattern, thereby to generate a second result;
and (c). storing the second result in the memory, thereby indirectly storing the first bit pattem

1794. A method according to claim 1771, for storing a bit-pattern in each of a plurality of devices, each of the devices having a memory, the method comprising, for each device:
(a). determining a first memory location; and (b). storing the bit-pattern at the first memory location; wherein the first memory locations are different in at least a plurality of the respective devices.

1795. A method according to claim 1771, for providing a sequence of nonces (R0, Rl, R2, ... ) commencing with a current seed of a sequence of seeds (x1, x2, x3,...), the method comprising:
(a). applying a one-way function to the current seed, thereby to generate a current nonce; (b) outputting the current nonce;
(b). using the current seed to generate a next seed in a sequence of seeds, the seed so generated becoming the current seed; and (c). repeating steps (a) to (c) as required to generate further nonces in the sequence of nonces.

1796. A method according to claim 1771, for storing multiple first bit-patterns in non-volatile memory of a device, the method comprising, for each of the first bit-patterns to be stored:

(a). applying a one way function to a third bit-pattern based on a second bit-pattern associated with the device, thereby to generate a first result;
(b). applying a second function to the first result and the first bit pattern, thereby to generate a second result;
and (c). storing the second result in the memory, thereby indirectly storing the first bit-pattern; wherein the third bit-patterns used for the respective first bit-patterns are relatively unique compared to each other.

1797. A method for providing a sequence of nonces (R0, R1, R2, ... ) commencing with a current seed of a sequence of seeds (x1, x2, x3,...), the method comprising:
(a). applying a one-way function to the current seed, thereby to generate a current nonce; (b) outputting the current nonce;
(b). using the current seed to generate a next seed in a sequence of seeds, the seed so generated becoming the current seed; and (c). repeating steps (a) to (c) as required to generate further nonces in the sequence of nonces.

1798. A method according to claim 1797, wherein x1 is generated based on an initial seed x0, the initial seed having been generated by a random number generator.

1799. A method according to claim 1798, the initial seed x0 having been generated based on a stochastic process.

1800. A method according to claim 1799, wherein the next seed is generated from the current seed on the basis of a second function.

1801. A method according to claim 1800, wherein the second function is less cryptographically strong than the one way function.

1802. A method according to claim 1801, wherein the second function is additive.

1803. A method according to claim 1797, wherein the second function is a linear feedback shift register function.

1804. A method according to claim 1797, wherein the one way function is a hash function.

1805. A method according to claim 1797, wherein the hash function is SHA1.

1806. A device for generating a sequence of nonces (R0, R1, R2, ... ), the device including: memory for storing a current seed of a sequence of seeds (xl, x2, x3,...)' a processor configured to:
(a). apply a one way function to the current seed to generate a current nonce;
and (b). use the current seed to generate a next seed in the sequence of seeds, the seed so generated becoming the current seed; and (c). storing the current seed in memory.

1807. A device according to claim 1806, configured to generate x1 in the seed sequence based on an initial seed x0, the initial seed being stored in a non-volatile manner in the device.

1808. A device according to claim 1806, wherein x0 was generated by a random number generator.

1809. A device according to claim 1808, the initial seed x0 having been generated based on a stochastic process.

1810. A device according to claim 1806, wherein the processor is configured to generate the next seed by applying a second function to the current seed.

1811. A device according to claim 1810, wherein the second function is less cryptographically strong than the one way function.

1812. A device according to claim 1811, wherein the second function is additive.

1813. A device according to claim 1806, wherein the second function is a linear feedback shift register function.

1814. A device according to claim 1806, wherein the memory is non-volatile.

1815. A device according to claim 1813, wherein the memory is flash memory.

1816. A device according to claim 1806, wherein the device comprises one or more integrated circuits.

1817. A device according to claim 1806, wherein the device comprises a monolithic integrated circuit.

1818. A device according to claim 1806, wherein the one way function is a hash function.

1819. A device according to claim 1818, wherein the hash function is SHA1.

1820. A method of manufacturing a series of devices, each of the devices being in accordance with claim 10 and including a non-volatile memory, the method comprising:
(a). generating a bit-pattern on the basis of a random or pseudo random process;
(b). storing the bit-pattern in a non-volatile manner in the device; wherein the device is configured to use the bit-pattern as an initial current seed, and to store subsequent generated seeds in the non-volatile memory.

1821. A method according to claim 1820, wherein the step of storing the bit-pattern in a non-volatile manner includes storing the value in a place other than in the non-volatile memory.

1822. A method according to claim 1821, wherein the bit-pattern is stored in non-erasable form.

1823. A method according to claim 1820, including the step of storing a program on the device, the program including the one way function for generating the current nonce from the current seed.

1824. A method according to claim 1823, wherein the one way function is a hash function.

1825. A method according to claim 1823, wherein the one way function is non-compressing.

1826. A method according to claim 1824, wherein the hash function is SHA1

1827. A method according to claim 1797, implemented in a first entity configured to authenticate a digital signature supplied by a second entity, wherein one of the entities includes a base key and the other of the entities includes a variant key and a bit-pattern, the variant key being based on the result of applying a one way function to the base key and the bit-pattern, the digital signature having been generated by the second entity using its key to digitally signing at least part of data to be authenticated, the first entity being configured to:
(a). receive the digital signature from the second entity;
(b). receive the data; and (c). authenticate the digital signature based on the received data and the first entity's key.

1828. A method according to claim 1797, implemented in a first entity including:
a first bit-pattern a non-volatile memory storing resource data, a first base key for use with at least a first variant key;
a second variant key for use with a second base key, the second variant key being the result of a one way function applied to: the second base key; and the first bit-pattern or a modified bit-pattern based on the first bit-pattern.

1829. A method according to claim 1797, for enabling or disabling a verification process of a first entity in response to a predetermined event, the first entity having at least one associated bit-pattern and at least one variant key, each of the variant keys having been generated by applying a one way function to: a base key; and one or more of the at least one bit patterns, respectively; or one or more alternative bit patterns, each of the alternative bit-patterns being based on one or the at least one bit-patterns, the method including the method including:
(a). determining that the predetermined event has happened; and (b). enabling or disabling at least one of the first variant keys in response the predetermined event.

1830. A method according to claim 1797, implemented in a system for enabling authenticated communication between a first entity and at least one other entity, the system including a second entity, wherein:
the first entity and the second entity share transport keys; and the second entity includes at least one authentication key configured to be transported from the second entity to the first entity using the transport keys, the authentication key being usable to enable the authenticated communication by the first entity.

1831. A method according to claim 1797, for storing a first bit-pattern in non-volatile memory of a device, the method comprising:
(a). applying a one way function to a second bit-pattern associated with the device, thereby to generate a first result;
(b). applying a second function to the first result and the first bit-pattern, thereby to generate a second result;
and (c). storing the second result in the memory, thereby indirectly storing the first bit-pattern.

1832. A method according to claim 1797, for storing a bit-pattern in each of a plurality of devices, each of the devices having a memory, the method comprising, for each device:
(a). determining a first memory location; and (b). storing the bit-pattern at the first memory location; wherein the first memory locations are different in at least a plurality of the respective devices.

1833. A method according to claim 1797, for storing at least one functionally identical code segment in each of a plurality of devices, each of the devices having a memory, the method comprising, for each device:
(a). determining a first memory location; and (b). storing a first of the at least one code segments in the memory at the first memory location; wherein the first memory location is different in at least a plurality of the respective devices.

1834. A method according to claim 1797, for storing multiple first bit-patterns in non-volatile memory of a device, the method comprising, for each of the first bit-patterns to be stored:
(a). applying a one way function to a third bit-pattern based on a second bit-pattern associated with the device, thereby to generate a first result;
(b). applying a second function to the first result and the first bit-pattern, thereby to generate a second result;
and (c). storing the second result in the memory, thereby indirectly storing the first bit-pattern; wherein the third bit-patterns used for the respective first bit-patterns are relatively unique compared to each other.

1835. A method of storing multiple first bit-patterns in non-volatile memory of a device, the method comprising, for each of the first bit-patterns to be stored:
(a). applying a one way function to a third bit-pattern based on a second bit pattern associated with the device, thereby to generate a first result;
(b). applying a second function to the first result and the first bit-pattern, thereby to generate a second result;
and (c). storing the second result in the memory, thereby indirectly storing the first bit-pattern;wherein the third bit-patterns used for the respective first bit patterns are relatively unique compared to each other.

1836. A method according to claim 1835, wherein step (c) comprises:
(d). determining a first memory location; and (e). storing the second result at the first memory location.

1837. A method according to claim 1836, wherein step (d) includes randomly selecting the first memory location.

1838. A method according to claim 1837, wherein step (d) includes selecting the first memory location based on a stochastic process or mechanism.

1839. A method according to claim 1836, wherein step (d) includes selecting the first memory location from an existing list or sequence of memory locations.

1840. A method according to claim 1835, wherein each third bit-pattern is generated from the second bit-pattern by removing, adding or changing one or more bits, bytes or characters of the second bit-pattern.

1841. A method according to claim 1840, wherein each third bit-pattern is generated from the second bit pattern by adding an index of one or more bits, bytes or characters to the second bit-pattern, the index having been added at any position of the identifier, including being appended before or after the identifier, or being distributed within the identifier.

1842. A method according to claim 1841, wherein the index added to the second bit-pattern for the respective second bit-patterns is derived from a series of indices.

1843. A method according to claim 1842, including the step of generating the index as required.

1844. A method according to claim 1835, wherein the one way function is more cryptographically secure than the second function.

1845. A method according to claim 1835, wherein the second function is a logical function.

1846. A method according to claim 1845, wherein the logical function is an XOR
function.

1847. A method according to claim 1835, wherein the one way function is a hash function.

1848. A method according to claim 1835, wherein each of the first bit-patterns is a key.

1849. A method according to claim 1835, further including the step of storing one or more code segments in the memory, the code segments being configured to run on a processor of the device, thereby enabling the device to, for each of first bit-patterns to be retrieved:
generate the third-bit pattern corresponding to the first bit pattern to be retrieved;
apply the one way function to the third bit-pattern, thereby to generate the first result; and apply a third function to the first result and the second result corresponding to the first bit-pattern to be retrieved, thereby to generate that first bit-pattern;
wherein the third function is the inverse of the second function.

1850. A method according to claim 1849, wherein the third function and the second function are the same.

1851. A method according to claim 1835, wherein the second bit-pattern was generated randomly or pseudo-randomly.

1852. A method according to claim 1835, the method further including the step, performed prior to step (a), of determining the second bit pattern.

1853. A method according to claim 1852, wherein determining the second bit-pattern includes generating the second bit-pattern randomly or pseudo-randomly.

1854. A method according to claim 1852, wherein determining the second bit-pattern includes generating the second bit-pattern based on a stochastic process or mechanism.

1855. A method according to claim 1852, wherein determining the second bit-pattern includes selecting the second-bit pattern from an existing list or sequence of bit-patterns.

1856. A method of storing multiple first bit-patterns in non-volatile memory of each of a plurality of devices, the method comprising, for each of the first bit-patterns to be stored:
(a). applying a one way function to a third bit-pattern based on a second bit pattern associated with the device, thereby to generate a first result;
(b). applying a second function to the first result and the first bit-pattern, thereby to generate a second result;
and (c). storing the second result in the memory, thereby indirectly storing the first bit-pattern; wherein the third bit-patterns used for the respective first bit-patterns in each device are relatively unique with respect to each other, and the second bit patterns of the respective devices are relatively unique with respect to each other.

1857. A method according to claim 1835, wherein step (c) comprises, for each device:
(d). determining a first memory location; and (e). storing the second result at the first memory location.

1858. A method according to claim 1857, wherein step (d) includes randomly selecting the first memory location.

1859. A method according to claim 1858, wherein step (d) includes selecting the first memory location based on a stochastic process or mechanism.

1860. A method according to claim 1857, wherein step (d) includes selecting the first memory location from an existing list or sequence of memory locations.

1861. A method according to claim 1857, wherein the first memory locations of the devices are selected such that, from device to device, there is no overlap of the positions of at least some of the bits, bytes or characters of the devices respective second results.

1862. A method according to claim 1857, wherein the first memory locations of the devices are selected such that, from device to device, positions of at least some of the bits, bytes or characters of the devices' respective second results overlap.

1863. A method according to claim 1857, wherein the first memory locations of the devices are selected such that, from device to device, bit, byte or character positions of the devices' respective second results are shuffled, rotated or otherwise ordered differently.

1864. A method according to claim 1863, wherein the first memory locations of the devices are selected such that, from device to device, bit, byte or character positions of the devices' respective second results are shuffled, rotated or otherwise ordered differently.

1865. A method according to claim 1856, wherein for each device, each third bit pattern is generated from the second bit-pattern by removing, adding or changing one or more bits, bytes or characters of the second bit-pattern.

1866. A method according to claim 1865, wherein for each device, each third bit-pattern is generated from the second bit-pattern by adding an index of one or more bits, bytes or characters to the second bit-pattern, the index having been added at any position of the identifier, including being distributed within the identifier.

1867. A method according to claim 1866, wherein the index added to the second bit-pattern for the respective second bit-patterns is derived from a series of indices.

1868. A method according to claim 1867, including the step, for each device, of generating the index as required.

1869. A method according to claim 1856, wherein the one way function is more cryptographically secure than the second function.

1870. A method according to claim 1856, wherein the second function is a logical function.

1871. A method according to claim 1870, wherein the logical function is an XOR
function.

1872. A method according to claim 1856, wherein the one way function is a hash function.

1873. A method according to claim 1856, wherein each of the first bit-patterns is a key.

1874. A method according to claim 1856, further including the step of storing one or more code segments in the memory of each device, the code segments being configured to run on a processor of each device, thereby enabling each device to, for each of first bit-patterns to be retrieved:
generate the third-bit pattern corresponding to the first bit pattern to be retrieved;
apply the one way function to the third bit-pattern, thereby to generate the first result and apply a third function to the first result and the second result corresponding to the first bit-pattern to be retrieved, thereby to generate that first bit-pattern;
wherein the third function is the inverse of the second function.

1875. A method according to claim 1874, wherein the third function and the second function are the same.

1876. A method according to claim 1856, wherein the second bit-pattern for each device was generated randomly or pseudo-randomly.

1877. A method according to claim 1876, wherein the second bit-pattern for each device was generated based on a stochastic process or mechanism.

1878. A device manufactured in accordance with the method of claim 1835.

1879. A device manufactured in accordance with the method of claim 1849.

1880. A plurality of devices manufactured in accordance with the method of claim 1856.

1881. A plurality of devices manufactured in accordance with the method of claim 1874.

1882. A method according to claim 1835, implemented in a first entity configured to authenticate a digital signature supplied by a second entity, wherein one of the entities includes a base key and the other of the entities includes a variant key and a bit-pattern, the variant key being based on the result of applying a one way function to the base key and the bit-pattern, the digital signature having been generated by the second entity using its key to digitally signing at least part of data to be authenticated, the first entity being configured to:
(a). receive the digital signature from the second entity;
(b). receive the data; and (c). authenticate the digital signature based on the received data and the first entity's key.

1883. A method according to claim 1835, implemented in a first entity including:
a first bit-pattern a non-volatile memory storing resource data, a first base key for use with at least a first variant key;
a second variant key for use with a second base key, the second variant key being the result of a one way function applied to: the second base key; and the first bit-pattern or a modified bit-pattern based on the first bit-pattem.

1884. A method according to claim 1835, for enabling or disabling a verification process of a first entity in response to a predetermined event, the first entity having at least one associated bit-pattern and at least one variant key, each of the variant keys having been generated by applying a one way function to: a base key; and one or more of the at least one bit-patterns, respectively; or one or more alternative bit patterns, each of the alternative bit-patterns being based on one or the at least one bit-patterns, the method including the method including:
(a). determining that the predetermined event has happened; and (b). enabling or disabling at least one of the first variant keys in response the predetermined event.

1885. A method according to claim 1835, implemented in a system for enabling authenticated communication between a first entity and at least one other entity, the system including a second entity, wherein:
the first entity and the second entity share transport keys; and the second entity includes at least one authentication key configured to be transported from the second entity to the first entity using the transport keys, the authentication key being usable to enable the authenticated communication by the first entity.

1886. A method according to claim 1835, for storing a first bit-pattern in non-volatile memory of a device, the method comprising:
(a). applying a one way function to a second bit-pattern associated with the device, thereby to generate a first result;
(b). applying a second function to the first result and the first bit-pattern, thereby to generate a second result;
and (c). storing the second result in the memory, thereby indirectly storing the first bit-pattern.

1887. A method according to claim 1835, for storing a bit-pattern in each of a plurality of devices, each of the devices having a memory, the method comprising, for each device:

(a). determining a first memory location; and (b). storing the bit-pattern at the first memory location; wherein the first memory locations are different in at least a plurality of the respective devices.

1888. A method according to claim 1835, for storing at least one functionally identical code segment in each of a plurality of devices, each of the devices having a memory, the method comprising, for each device:
(a). determining a first memory location; and (b). storing a first of the at least one code segments in the memory at the first memory location; wherein the first memory location is different in at least a plurality of the respective devices.

1889. A method according to claim 1835, for providing a sequence of nonces (R0, R1, R2, ... ) commencing with a current seed of a sequence of seeds (x1, x2, x3,...), the method comprising:
(a). applying a one-way function to the current seed, thereby to generate a current nonce; (b) outputting the current nonce;
(b). using the current seed to generate a next seed in a sequence of seeds, the seed so generated becoming the current seed; and (c). repeating steps (a) to (c) as required to generate further nonces in the sequence of nonces.