EP1642723B1 - Druckverfahren und Gerät zum Mindern des Bandeffektes verursacht durch Papiertransport - Google Patents

Druckverfahren und Gerät zum Mindern des Bandeffektes verursacht durch Papiertransport Download PDF

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Publication number
EP1642723B1
EP1642723B1 EP05111886A EP05111886A EP1642723B1 EP 1642723 B1 EP1642723 B1 EP 1642723B1 EP 05111886 A EP05111886 A EP 05111886A EP 05111886 A EP05111886 A EP 05111886A EP 1642723 B1 EP1642723 B1 EP 1642723B1
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EP
European Patent Office
Prior art keywords
printing
head
image
sub
printed
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EP05111886A
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English (en)
French (fr)
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EP1642723A3 (de
EP1642723A2 (de
Inventor
Rudi Vanhooydonck
Patrick Van Den Bergen
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Agfa NV
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Agfa Graphics NV
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
    • B41J—TYPEWRITERS; SELECTIVE PRINTING MECHANISMS, i.e. MECHANISMS PRINTING OTHERWISE THAN FROM A FORME; CORRECTION OF TYPOGRAPHICAL ERRORS
    • B41J2/00—Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed
    • B41J2/005—Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed characterised by bringing liquid or particles selectively into contact with a printing material
    • B41J2/01—Ink jet
    • B41J2/21—Ink jet for multi-colour printing
    • B41J2/2132—Print quality control characterised by dot disposition, e.g. for reducing white stripes or banding
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
    • B41J—TYPEWRITERS; SELECTIVE PRINTING MECHANISMS, i.e. MECHANISMS PRINTING OTHERWISE THAN FROM A FORME; CORRECTION OF TYPOGRAPHICAL ERRORS
    • B41J11/00—Devices or arrangements  of selective printing mechanisms, e.g. ink-jet printers or thermal printers, for supporting or handling copy material in sheet or web form
    • B41J11/36—Blanking or long feeds; Feeding to a particular line, e.g. by rotation of platen or feed roller
    • B41J11/42—Controlling printing material conveyance for accurate alignment of the printing material with the printhead; Print registering
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
    • B41J—TYPEWRITERS; SELECTIVE PRINTING MECHANISMS, i.e. MECHANISMS PRINTING OTHERWISE THAN FROM A FORME; CORRECTION OF TYPOGRAPHICAL ERRORS
    • B41J11/00—Devices or arrangements  of selective printing mechanisms, e.g. ink-jet printers or thermal printers, for supporting or handling copy material in sheet or web form
    • B41J11/36—Blanking or long feeds; Feeding to a particular line, e.g. by rotation of platen or feed roller
    • B41J11/42—Controlling printing material conveyance for accurate alignment of the printing material with the printhead; Print registering
    • B41J11/425—Controlling printing material conveyance for accurate alignment of the printing material with the printhead; Print registering for a variable printing material feed amount

Definitions

  • the present invention relates to a method for printing, such as ink jet or thermal transfer printing, especially non-contact printing.
  • Printing is one of the most popular ways of conveying information to members of the general public.
  • Digital printing using dot matrix printers allows rapid printing of text and graphics stored on computing devices such as personal computers. These printing methods allow rapid conversion of ideas and concepts to printed product at an economic price without time consuming and specialised production of intermediate printing plates such as lithographic plates.
  • the development of digital printing methods has made printing an economic reality for the average person even in the home environment.
  • a printing head e.g. an ink jet printing head
  • marking elements e.g. ink jet nozzles.
  • the marking elements transfer a marking material, e.g. ink or resin, from the printing head to a printing medium, e.g. paper or plastic.
  • CMYK plus one or more additional spot or specialised colours To print a printing medium such as paper or plastic, the marking elements are used or “fired” in a specific order while the printing medium is moved relative to the printing head. Each time a marking element is fired, marking material, e.g. ink, is transferred to the printing medium by a method depending on the printing technology used.
  • marking material e.g. ink
  • the head will be moved relative to the printing medium to produce a so-called raster line which extends in a first direction, e.g. across a page.
  • the first direction is sometimes called the "fast scan” direction.
  • a raster line comprises a series of dots delivered onto the printing medium by the marking elements of the printing head.
  • the printing medium is moved, usually intermittently, in a second direction perpendicular to the first direction. The second direction is often called the slow scan direction.
  • the distance between dots of the dot matrix is small, that is the printing has a high resolution.
  • high resolution always means good printing
  • a minimum resolution is necessary for high quality printing.
  • a small dot spacing in the slow scan direction means a small distance between marker elements on the head, whereas regularly spaced dots at a small distance in the fast scan direction places constraints on the quality of the drives used to move the printing head relative to the printing medium in the fast scan direction.
  • a mechanism for positioning a marker element in a proper location over the printing medium before it is fired is controlled by a microprocessor, a programmable digital device such as a PAL, a PLA, a FPGA or similar although the skilled person will appreciate that anything controlled by software can also be controlled by dedicated hardware and that software is only one implementation strategy.
  • One general problem of dot matrix printing is the formation of artefacts caused by the digital nature of the image representation and the use of equally spaced dots.
  • Certain artefacts such as Moiré patterns may be generated due to the fact that the printing attempts to portray a continuous image by a matrix or pattern of (almost) equally spaced dots.
  • One source of artefacts can be errors in the placing of dots caused by a variety of manufacturing defects such as the location of the marker elements in the head or systematic errors in the movement of the printing head relative to the printing medium. In particular, if one marking element is misplaced or its firing direction deviates from the intended direction, the resulting printing will show a defect which can run throughout the printing.
  • a variation in drop velocity will also cause artefacts when the printing head is moving, as time of flight of the drop will vary with variation in the velocity.
  • a systematic error in the way the printing medium is moved relative to the printing medium may result in defects that may be visible.
  • slip between the drive for the printing medium and the printing medium itself will introduce errors.
  • any geometrical limitation of the printing system can be a source of errors, e.g. the length of the printing head, the spacing between marking elements, the indexing distance of the printing medium relative to the head in the slow scan direction.
  • Such errors may result in "banding" that is the distinct impression that the printing has been applied in a series of bands.
  • the errors involved can be very small - the colour discrimination, resolution and pattern recognition of the human eye are so well developed that it takes remarkably little for errors to become visible.
  • each printing location or "pixel” can be printed by four dots, one each for cyan, magenta, yellow and black. Adjacent pixels on a raster line are not printed by the same nozzle in the printing head. Instead, every other pixel is printed using the same nozzle. In the known system the pixels are printed in a checkerboard pattern, that is, as the head traverses in the fast scan direction a nozzle is able to print at only every other pixel location.
  • any nozzle which prints consistently in error does not result in a line of pixels in the slow scan direction each of which has the same error.
  • the result is that only 50% of the nozzles in the head can print at any one time.
  • each nozzle prints at a location which deviates a certain amount from the correct position for this nozzle.
  • the use of shingling can distribute these errors through the printing. It is generally accepted that shingling is an inefficient method of printing as not all the nozzles are used continuously and several passes are necessary.
  • interlacing Another method of printing is known as "interlacing", e.g. as described in US 4,198,642 .
  • the purpose of this type of printing is to increase the resolution of the printing device. That is, although the spacing between nozzles on the printing head along the slow scan direction is a certain distance X, the distance between printed dots in the slow scan direction is less than this distance.
  • the relative movement between the printing medium and the printing head is indexed by a distance given by the distance X divided by an integer.
  • EP-1014297 and EP-1014299 describe methods and devices for reducing banding by providing an accumulated error position which falls on a different location for each colour.
  • a selection of working nozzles is made that results in the spacing between adjacent groups of working nozzles being a number of times the nozzle pitch, whereby that number is 2 or more.
  • US-5940093 and US-6068366 describe methods for printing with a printer system, wherein a relocation error is induced in a paper transport system so as to randomise, bias or redistribute harmonic errors associated with the paper transport system of a printer system.
  • a first subset of an addressable set of ink emitting orifices in the printhead are used to print on the print medium at a registration location.
  • the print medium is then moved in a reverse direction a predetermined distance, and the print medium is then again advanced in the advance direction and relocated at the registration location.
  • a second subset of the addressable set of ink emitting orifices in the printhead are then used to print on the relocated print medium at the registration location.
  • a disadvantage of this method is that the printer system must be adapted to move the print medium in an advance and in a reverse direction.
  • EP 961 222 an image is recorded using recording and non-recording band regions of a printhead, but also no attention is given to the position of the transition lines between the swaths.
  • EP 1 132 213 discloses the use of uneven step distances between printing passes to avoid banding, but efficiency is not optimal due to throughput loss in certain cases.
  • a dot matrix printing method according to current invention for printing an image with reduced banding on a printing medium is described in the independent claim 1.
  • thermal transfer printing thermal dye transfer printing, deflected ink jet printing, ion projection printing, field control printing, impulse ink jet printing, drop-on-demand ink jet printing, continuous ink jet printing.
  • Non-contact printing methods are particularly preferred.
  • the present invention is not limited thereto. Any form of printing including dots or droplets on a substrate is included within the scope of the present invention, e.g. piezoelectric printing heads may be used to print polymer materials as used and described by Plastic Logic ( http://plasticlogic.com /) for the printing of thin film transistors.
  • the term "printing" in accordance with the present invention not only includes marking with conventional staining inks but also the formation of printed structures or areas of different characteristics on a substrate.
  • the term "printing medium” or “printing substrate” should also be given a wide meaning including not only paper, transparent sheets, textiles but also flat plates or curved plates which may be included in or be part of a printing press.
  • the printing may be carried out at room temperature or at elevated temperature, e.g. to print a hot-melt adhesive the printing head may be heated above the melting temperature.
  • the term "ink” should also be interpreted broadly including not only conventional inks but also solid materials such as polymers which may be printed in solution or by lowering their viscosity at high temperatures as well as materials which provide some characteristic to a printed substrate such as information defined by a structure on the surface of the printing substrate, water repellence, or binding molecules such as DNA which are spotted onto microarrays.
  • solvents both water and organic solvents may be used.
  • Inks as used with the present invention may include a variety of additives such as ant-oxidants, pigments and cross-linking agents.
  • a dot matrix printing head of a kind which may be used with the present invention is shown schematically in Fig. 1 .
  • a scanning printing head 10 may have an elongate form having a longitudinal axis 50.
  • the printing head 10 comprises a plurality of marker elements 11, for example a plurality of ink jetting orifices 12-1.... 12-n, 13-1 across 13-n, 14-1 across 14-n, 15-1 across 15-n for the colours yellow, magenta, cyan and black each arranged in an array 12, 13, 14, 15 respectively which may comprise one or more rows.
  • the head 10 is moved relative to a printing medium (such as paper) in the direction indicated with the arrow "Y" known as the fast scan direction which is, in the example given, perpendicular to the longitudinal axis 50 of the head 10.
  • a printing medium such as paper
  • the head 10 may be placed in a slanted position with regard to the fast scan direction Y, to increase the printing resolution.
  • the printing head 10 may comprise an ink cartridge carried on a movable carriage assembly. By repeatedly firing the arrays 12, 13, 14, 15 of nozzles 11 and moving in the fast scan direction ink drops are deposited on the printing medium in parallel lines across the printing medium in accordance with an image to be printed. Each line of printing from a single nozzle 11 is known as a raster line.
  • the printing head 10 may print on the way back - i.e. printing a second pass, or the printing head 10 may only print when moving in one direction.
  • the printing medium may be indexed in the slow scan direction X (perpendicular to the fast scan direction Y and parallel to the longitudinal axis 50 of the printing head 10 in the example given in the drawings) between passes.
  • the firing of the nozzles 11 is controlled by a control device, e.g. a microprocessor or microcontroller (see Fig. 7 ), the firing being in accordance with a digital representation of an image which is processed by the control device.
  • the digital representation of an image may be provided by a graphics software program running on a host computer or by scanning in an image. In this way a complete image is printed.
  • nozzle pitch nozzle pitch
  • Fig. 2 shows how an image is divided in sub-images, which are mutually interstitially printed using a Mutual Interstitial Printing Ratio (MIPR) of 25% but which are not interlaced.
  • MIPR Mutual Interstitial Printing Ratio
  • nozzles in a first fraction print every so many pixels, e.g. every fourth pixel in a column in the fast scan direction Y, beginning with the first row which is able to print. This is indicated by a 1 in the table of Fig. 2 .
  • a 1 in the table indicates the ability of the relevant nozzle to print at a location - it does not mean that it always prints at this location. Also, going down a "column" of the tables in the attached figures refers to going along the fast scan direction Y, i.e. the direction perpendicular to the longitudinal axis 50 of the printing head 10 in the example given.
  • the head 10 After the first scan across the printing medium is complete, the head 10 is returned to the starting position and is transported a quarter of its length with respect to the printing medium in the slow scan direction (X) ready for pass 2.
  • length of the head is meant the length of the number of active nozzles available for the printing process. This is not necessarily the same as the length of the total number of nozzles on the head as the present invention includes using a sub-set of these nozzles for the printing operation. In this embodiment it is assumed that the head 10 does not print on the return trip but printing in both fast scan directions Y and -Y is included within the scope of the present invention.
  • the first half of the head 10 is printing every fourth pixel, beginning with the second row in the table (indicated by a 2 in the table).
  • the print head 10 is displaced a quarter of its length again.
  • the first 3/4 of the head 10 is printing every fourth pixel, beginning with the third row (indicated by 3).
  • the print head 10 is transported a quarter of its length again in the slow scan direction. From now on the printer is printing with all nozzles every fourth pixel.
  • the print head 10 is transported a quarter of its length again and the fifth pass (number 5) is printed every fourth row beginning with row 1 again in a new cycle. Such cycles are repeated continuously.
  • the cycle repeats every four passes - this is 25% mutually interstitial printing. Because in each column each four successive dots are each printed with a different nozzle, banding problems due to nozzle-misalignment are hidden.
  • the head/printing medium movement in between the first passes don't have to have the same length. They can have any length provided the following condition is fulfilled: the distance represented by the sum of the head/printing medium relative movements in the first P passes, where P is an integer (4 in the above example), has to be equal to the exact active nozzle length, i.e. the length of the nozzle array of active nozzles (nozzles which are used to print or not print at a location), measured in nozzles.
  • Interlacing is a technique to obtain a higher resolution printed image than would be expected based on the nozzle distance np. For example, interlacing allows writing a 720dpi (dots per inch) image with a 180dpi head (i.e. the nozzles are spaced on the head so as to generate 180 dpi). With interlacing using a scanning head 10 the slow scan pixel pitch, that is the pitch of dots printed on the printing medium in the slow scan direction is smaller than the nozzle pitch np of the head 10 in the slow scan direction.
  • the slow scan direction for a scanning head 10 as shown in Fig. 1 is parallel to the longitudinal axis 50 of the head. However, in an alternative embodiment, the slow scan direction may be slanted with regard to the scanning head 10.
  • a first part of the head 10 (e.g. the first quarter) prints first every so many columns, e.g. every fourth column. Then the head 10 is transported by one pixel pitch + (k 1 * nozzle pitch), (note: k 1 is an integer which may be zero). Then in the next pass the head 10 prints again every so many columns, e.g. every fourth column beginning with the second one, then the print head is transported one pixel pitch + (k 2 * nozzle pitch), (k 2 is an integer which may be zero). This procedure is repeated a number of times, e.g. a third time and a fourth time, after which the print head can be displaced the rest of the head length.
  • both mutually interstitial printing and interlacing are carried out to improve printing quality and to avoid banding.
  • an image is divided in sub-images which are mutually interstitially printed 25% (generally: 100/P % with P the number of passes for the mutually interstitial printing) and interlaced to order 4.
  • This printing method will be described with reference to Fig. 4 , for example for a 720dpi image formed when sub-images are mutually interstitially printed 25% and interlaced to order 4.
  • the head 10 writes first an image made up of the pixel positions having the "11" symbol.
  • the first digit "1" is the number of the pass used in mutually interstitial printing
  • the second digit "1" is the number of the pass in interlacing.
  • An example of the printing procedure is given below:
  • the head 10 writes during the first pass with nozzle 1 in column 1 at pixels defined by symbol "11” in rows 1, 5, 9 etc. along the fast scan direction.
  • the head 10 prints with nozzle 2 in the same pass pixel positions defined by the symbol "11” in column 5, row 1, 5, 9 etc. and prints with nozzle 3 the pixels defined by the symbol "11” in column 9, row 1, 5, 9 etc. The same is happening for the other nozzles.
  • the head After printing the complete sub-image for "11", the head writes, during a second pass, the sub-image defined by the symbol "12" in the same way.
  • the head moves a pixel pitch plus k times a nozzle distance and the first interlacing level is performed for all mutually interstitial printing operations to complete another sub-image (e.g. "12"). Any other of the symbols can also be printed in this fashion.
  • These 16 sub-images can be written completely independent from each other. Therefore, in general, the interlacing steps will be intercalated with mutually interstitial printing so that all the sub-images are being created concurrently rather than one after another. In fact the order in which the sub-images are printed, i.e.
  • a swath is defined by a part of a sub-image printed within a head length in one pass as shown in Fig. 5 , the head length being the length of active nozzles able to fire in one pass.
  • one sub-image e.g. the "11" sub-image
  • the second swath for the "11" sub-image is printed.
  • the second swath for one symbol e.g.
  • the swath boundaries or swath transition lines for the sub-images "11" etc. do not fall together on the same line. Ideally, no two swath boundaries fall together onto one line.
  • any systematic error caused by the length of the printing head can be hidden. It is the selection of the sequence of traversing the sub-image matrix (see (1) above) which determines where the swath boundaries will lie.
  • banding due to paper transport can be suppressed.
  • the step distance for the relative motion between printing medium and the print head in the printing direction needs to be controlled.
  • h the number of nozzle rows written at the same time.
  • Mutually interstitial printing of sub-images is used in the above examples to avoid banding due to nozzle misalignment. It is generally held that it is not possible to mutually interstitially print without slowing down the throughput of the system or without making a significant number of the nozzles in a head idle some of the time.
  • mutually interstitial printing of sub-images can be made more efficient by increasing the speed of traverse in the fast scan direction. Because each sub-image is a 180dpi image, and because each of these images is independent of each other, each sub-image can be written with a minimum time between two neighbouring pixels. This is called fast mutually interstitial printing.
  • the first row and the second row of a sub-image can be printed after the shortest time possible between two dots for example, 100 ⁇ s if a 10kHz head is used, while in conventional mutually interstitial printing, there are 100 ⁇ s between each two lines of the image to be printed, thus for 25% mutually interstitial printing with a 10 kHz head there is 400 ⁇ s between the first and the second row of a sub-image. None of the intermediate pixels have to be printed in the same time when using fast mutually interstitial printing.
  • the present invention also includes a single printing operation of a line of dots with less than the full compliment of active nozzles, i.e. to select a specific redundancy of the nozzles, for example only every other active nozzle is available for firing at each print operation. This is the same as conventional mutually interstitial printing of sub-images in which there is a redundancy in the number of nozzles. If every other nozzle is used in one pass, this would mean a redundancy of 50%.
  • mixed mutually interstitial printing which is a combination of fast and normal mutually interstitial printing. This means that part of an image is printed by fast mutually interstitial printing, and the other part of the image is printed by normal mutually interstitial printing. In this way, redundancy is obtained: one pixel can be reached more than once.
  • the fast mutually interstitial printed part of the image comprises the highest possible number of sub-images, preferably all sub-images.
  • any combination of fast and slow mutually interstitial printing is possible, e.g. one sub-image being fast mutually interstitial printed, and all the other sub-images being conventionally mutually interstitially printed.
  • the printing head 10 shown in Fig. 1 illustrates a printing head 10 consisting of four heads 22, 23, 24, 25, for yellow, cyan, magenta, and black respectively. Each head has a plurality of ink jetting orifices 12-1.... 12-n, 13-1 across 13-n, 14-1 across 14-n, 15-1 across 15-n for each colour.
  • the distance in the slow scan direction X between the first nozzle 12-2, 13-2, 14-2 of a first nozzle row 16 of a first head 22, 23, 24 and the first nozzle 13-2, 14-2, 15-2 of a first nozzle row 16 of a second head 23, 24, 25, further called x2 should be chosen such that all heads are equally spread over the distance TD. This can be done by choosing x1 and x2 equal to approximately TD/h. In this way all swath transition lines will be spread equally over the image.
  • the configuration of the heads can be optimised in this way.
  • a full colour image of 720 dpi is to be printed . Therefore the image is to be divided in sub-images which are mutually interstitially printed 25% and interlaced 4 times.
  • Four heads 22, 23, 24, 25 are used, each having two nozzle rows 16, 17 each comprising n nozzles.
  • Each head 22, 23, 24, 25 has a different colour, e.g. yellow, magenta, cyan, black. From the above, it is easy to calculate that his image consists of 64 sub-images (C*P*I).
  • Each of these sub-images can be written by a head that writes the first n columns. The paper is transported, and the following n columns are written, etc., as explained with regard to Fig.2 .
  • 4 heads 22, 23, 24, 25 each having two nozzle rows 16, 17, eight swaths are printed in the same time before a next paper transport.
  • the heads 22, 23, 24, 25 should be organised so that the distance between nozzles of different nozzle rows is as indicated hereinabove. For the present system this means:
  • the image process steps look as follows: when the first nozzle array of the first head is writing the "11"-sub-image, the second nozzle array of the same head can write one of the following images: "13", “23”, “33”, "43". Which of those images can be printed, depends on the timing when the dots are printed. The other 15 locations are also possible, but then another configuration of the heads is necessary.
  • nozzle rows printing different colours are staggered.
  • the distance x2 between the first nozzle of the first nozzle row and the first nozzle of the second nozzle row has to be at least (2*I/hs)/(T) of a nozzle row length in the slow scan direction, with I the number of interlacing passes, hs the number of nozzle rows printing the same colour, and T the number of transport steps to reach one head length.
  • the distance x2 has to be at least (3*I/hs)/(T) times the nozzle row length in the slow scan direction. In this case a drop of the second colour is always on top of a drop of the first colour.
  • Fig. 6 is a highly schematic general perspective view of an inkjet printer 20 which can be used with the present invention.
  • the printer 20 includes a base 31, a carriage assembly 32, a step motor 33, a drive belt 34 driven by the step motor 33, and a guide rail assembly 36 for the carriage assembly 32.
  • Mounted on the carriage assembly 32 is a print head 10 that has a plurality of nozzles.
  • the print head 10 may also include one or more ink cartridges or any suitable ink supply system.
  • a sheet of paper 37 is fed in the slow scan direction over a support 38 by a feed mechanism (not shown).
  • the carriage assembly 32 is moved along the guide rail assembly 36 by the action of the drive belt 34 driven by the step motor 33 in the fast scanning direction.
  • Fig. 7 is a block diagram of the electronic control system of a printer 20, which is one example of a control system for use with a print head 10 in accordance with the present invention.
  • the printer 20 includes a buffer memory 40 for receiving a print file in the form of signals from a host computer 30, an image buffer 42 for storing printing data, and a printer controller 60 that controls the overall operation of the printer 10.
  • a fast scan driver 62 for a carriage assembly drive motor 66
  • a slow scan driver 64 for a paper feed drive motor 68
  • a head driver 44 for the print head 10.
  • a data store 70 for storing parameters for controlling printing operation.
  • Host computer 30 may be any suitable programmable computing device such as personal computer with a Pentium III microprocessor supplied by Intel Corp. USA, for instance, with memory and a graphical interface such as Windows 98 as supplied by Microsoft Corp. USA.
  • the printer controller 60 may include a computing device, e.g. microprocessor, for instance it may be a microcontroller.
  • it may include a programmable printer controller, for instance a programmable digital logic element such as a Programmable Array Logic (PAL), a Programmable Logic Array, a Programmable Gate Array, especially a Field Programmable Gate Array (FPGA).
  • PAL Programmable Array Logic
  • FPGA Field Programmable Gate Array
  • control unit 60 is adapted for a dot matrix printer for printing an image on a printing medium with reduced banding, by moving, relative to the printing medium, a printing head, in a fast scan direction Y during a plurality of printing passes, the printing head having a contiguous set of equally spaced marking elements, the marking elements available to be fired at firing moments being a set of active marking elements, the length of the active marking elements on the printing head in a slow scan direction perpendicular to the fast scan direction being the head length, the control unit comprising: means for segregating the image into at least two sub-images, and means for controlling the printing of the at least two sub-images during the plurality of printing passes by mutually interstitial printing steps and/or interlacing steps, means for controlling the movement of the printing medium relative to printing head with a transport distance step in the slow scan direction X between the printing passes of the at least two sub-images, whereby the sum of all transport distance steps after writing one swath of each sub-image is exactly equal to the
  • the user of printer 20 can optionally set values into the data store 70 so as to modify the operation of the printer head 10.
  • the user can for instance set values into the data store 70 by means of a menu console 46 on the printer 20.
  • these parameters may be set into the data store 70 from host computer 30, e.g. by manual entry via a keyboard.
  • a printer driver (not shown) of the host computer 30 determines the various parameters that define the printing operations and transfers these to the printer controller 60 for writing into the data store 70. Based on these parameters, the printer controller reads the required information contained in the printing data stored in the buffer memory 40 and sends control signals to the drivers 62, 64 and 44.
  • the printing data is broken down into the individual colour components to obtain image data in the form of a bit map for each colour component which is stored in the receive buffer memory 30.
  • the sub-images are derived from this bit map, in particular each sub-image will start at a certain offset within the bit map.
  • the head driver 44 reads out the colour component image data from the image buffer memory 52 in accordance with a specified sequence of printing the sub-images and uses the data to drive the array(s) of nozzles on the print head 10 to mutually interstitially print the sub-images.
  • the data which is stored in data store 70 may comprise:
  • the present invention includes the storing of alternative representations of this data which however amount to the same technique of printing.
  • a) to d) there can be a default value which is assumed to apply if the user does not enter any values.
  • at least one of the parameters a) to d) is settable by the user.
  • the sequence of offsets and therefore the sequence of dealing with the sub-images
  • the user may freely set the number of sub-images to be printed by selecting one or more of the number of passes, the percentage redundancy and the number of interlacing lines.
  • the user may select the complexity of the printing process which has an effect on the quality of print (e.g. lack of banding effects, masking defective nozzles) as well as the time to print (number of passes before the printing is complete).
  • the present invention also includes that items a) to d) above are machine settable, for instance printer controller 60 sets the parameters for printing, e.g. at least one of items a) to d) above, e.g. in accordance with an optimised algorithm.
  • the controller 60 may be programmable, e.g. it may include a microprocessor or an FPGA.
  • a printer in accordance with the present invention may be programmed to provide different levels of printing complexity.
  • the basic model of the printer may provide selection of at least one of the number and sequence of printing of the sub-images.
  • An upgrade in the form of a program to download into the microprocessor or FPGA of the controller 60 may provide additional selection functionality, e.g.
  • the printer controller 60 controls the carriage assembly drive 66, the paper feed rive 68 and the head driver 44 to carry out the printing methods of the present invention.
  • the present invention includes a computer program product which provides the functionality of any of the methods according to the present invention when executed on a computing device.
  • the present invention includes a data carrier such as a CD-ROM or a diskette which stores the computer product in a machine readable form and which executes at least one of the methods of the invention when executed on a computing device.
  • a data carrier such as a CD-ROM or a diskette which stores the computer product in a machine readable form and which executes at least one of the methods of the invention when executed on a computing device.
  • a computing device may include one of a microprocessor and an FPGA.
  • the data store 70 may comprise any suitable device for storing digital data as known to the skilled person, e.g. a register or set of registers, a memory device such as RAM, EPROM or solid state memory.
  • the parameters for determining the combined mutual interstitial and interlaced printing are stored in data store 70.
  • the preparation for the printing file to carry out the above mentioned printed embodiments may be prepared by the host computer 30 and the printer 20 simply prints in accordance with this file as a slave device of the host computer 30.
  • the present invention may include that the printing schemes of the present invention are implemented in software on a host computer and printed on a printer which carries out the instructions from the host computer without amendment.
  • the present invention may include a computer program product which provides the functionality of any of the methods according to the present invention when executed on a computing device which is associated with a printing head, that is the printing head and the programmable computing device may be included with the printer or the programmable device may be a computer or computer system, e.g. a Local Area Network connected to a printer.
  • the printer may be a network printer.
  • the present invention includes a data carrier such as a CD-ROM or a diskette which stores the computer product in a machine readable form and which can execute at least one of the methods of the invention when the program stored on the data carrier is executed on a computing device.
  • the computing device may include a personal computer or a work station.
  • the present invention may include transmitting the printing computer product according to the present invention over a local or wide area network.

Landscapes

  • Engineering & Computer Science (AREA)
  • Quality & Reliability (AREA)
  • Ink Jet (AREA)
  • Electronic Switches (AREA)

Claims (2)

  1. Ein Punktmatrixdruckverfahren zum Drucken eines Bildes mit verringerter Streifenbildung auf einem Druckmedium (37) unter Verwendung eines Abtastdrucksystems mit einem mit einem Satz benachbarter, abstandsgleich angeordneter Markierelemente (12, 13, 14, 15) versehenen Druckkopf (10), wobei sich der Druckkopf während Druckdurchläufe relativ zum Druckmedium in einer Abtastbewegung in eine schnelle Abtastrichtung (Y) verschiebt und sich das Druckmedium zwischen zwei Druckdurchläufen während Förderschritte in eine Bewegung relativ zum Druckkopf in eine langsame Abtastrichtung (X) zum Druckkopf verschiebt,
    wobei das Druckverfahren folgende Schritte umfasst :
    - Bereitstellen eines Subsatzes von Markierelementen des Kopfes, die zu Schiessmomenten während Druckdurchläufe Tinte schießen und einen Satz aktiver Markierelemente bilden, wobei die Länge des Satzes aktiver Markierelemente auf dem Druckkopf in eine senkrecht auf der schnellen Abtastrichtung (Y) verlaufende langsame Abtastrichtung (X) die Kopflänge definiert,
    - Aufteilen des Bildes in N Teilbilder, wobei N folgendem Wert entspricht :
    - der Anzahl verwendeter Farben (C), multipliziert mit
    - der Anzahl der gegenseitig interstitiellen Druckschritte (P), zum Drucken von Teilbildern, wobei mindestens ein Teil der Räume in einem gedruckten Teilbild eine Stelle für die gedruckten Teile eines anderen Teilbildes bildet, und umgekehrt, und wobei benachbarte Pixel auf einer Rasterlinie nicht durch ein und dieselbe Düse gedruckt werden, und multipliziert mit
    - der Anzahl der Interlacing-Druckschritte (I), wobei Teilbilder gedruckt werden, deren Punkte in die langsame Abtastrichtung in einem Abstand zu anderen Punkten, der kleiner ist als der Abstand zwischen den Düsen, gedruckt werden, (N=C*P*I),
    wobei jedes Teilbild aus einer Vielzahl von Durchlaufbändern zusammengesetzt ist und jedes Band einem Teil eines Teilbildes, der in einem einzelnen Durchlauf durch den Satz aktiver Markierelemente gedruckt wird, entspricht, wobei die Durchlaufbänder Bandgrenzen aufweisen,
    - Drucken des Bildes in Form von mindestens zwei Teilbildern, wobei abwechselnd folgende Schritte vorgenommen werden :
    - mehrere Druckdurchläufe, wobei mindestens ein Durchlaufband von mindestens einem Teilbild während jeden Druckdurchlaufs gedruckt wird und die zum Drucken der benötigten Farben erforderliche Anzahl der gegenseitig interstitiellen Druckschritte und Interlacing-Druckschritte vorgenommen wird,
    - Förderschritte mit einer relativen Bewegung des Druckmediums zum Druckkopf zwischen Druckdurchläufen, wobei jeder Förderschritt einen Schrittabstand in die langsame Abtastrichtung (X) umfasst,
    dadurch gekennzeichnet, dass
    - die nach Drucken eines Durchlaufbandes jedes Teilbildes ermittelte Summe aller Förderschrittabstände genau der Kopflänge entspricht,
    - die in Düsen gemessenen Abstände der Förderschritte folgende sind :
    - (I-1) x [n/T - 1dp/np] und
    - 1 x [n/T + (I-1) dp/np]
    wobei n die Anzahl der in einer Reihe in die Förderrichtung einer Anordnung von Markierelementen der Druckkopfkonfiguration verwendeten Markierelemente (11) bedeutet,
    wobei T die Anzahl der zum Erhalten einer Kopflänge benötigten Förderschritte bedeutet,
    wobei dp den Abstand zwischen zwei Pixeln bedeutet und
    wobei np den Abstand zwischen zwei Markierelementen bedeutet, so dass alle Grenzlinien des Durchlaufbandes zwischen zwei aufeinanderfolgenden Banddruckdurchläufen jedes Teilbildes auf dem Druckbild wesentlich abstandsgleich über die Länge des Druckkopfs verteilt sind.
  2. Verfahren nach Anspruch 1, dadurch gekennzeichnet, dass die Sequenz der Vorschubabstände eine Anzahl von Malen, gleich der Anzahl der verwendeten Farben, multipliziert mit der Anzahl der gegenseitig interstitiellen Druckschritte und geteilt durch die Anzahl der auf einmal gedruckten Düsenreihen, wiederholt wird ((C x P) / h mal).
EP05111886A 2001-10-31 2001-10-31 Druckverfahren und Gerät zum Mindern des Bandeffektes verursacht durch Papiertransport Expired - Lifetime EP1642723B1 (de)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
EP01000585A EP1308292A1 (de) 2001-10-31 2001-10-31 Druckverfahren und Gerät zum Mindern des Bandeffektes verursacht durch Papiertransport

Related Parent Applications (2)

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EP01000585A Division EP1308292A1 (de) 2001-10-31 2001-10-31 Druckverfahren und Gerät zum Mindern des Bandeffektes verursacht durch Papiertransport
EP01000585.8 Division 2001-10-31

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EP1642723A2 EP1642723A2 (de) 2006-04-05
EP1642723A3 EP1642723A3 (de) 2006-11-15
EP1642723B1 true EP1642723B1 (de) 2012-05-23

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JP5123519B2 (ja) * 2006-11-24 2013-01-23 株式会社ミマキエンジニアリング 印刷装置及び印刷方法
CN111439031A (zh) * 2020-05-13 2020-07-24 苏州新锐发科技有限公司 打印设备及方法
CN111923599B (zh) * 2020-09-18 2021-02-26 季华实验室 喷头模组步长计算方法、设备、存储介质和喷墨打印机
CN115447284B (zh) * 2021-06-08 2023-09-08 深圳市汉森软件有限公司 消除喷头色差的打印方法、装置、设备及存储介质

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US4198642A (en) 1978-01-09 1980-04-15 The Mead Corporation Ink jet printer having interlaced print scheme
US4967203A (en) 1989-09-29 1990-10-30 Hewlett-Packard Company Interlace printing process
US5940093A (en) 1997-03-14 1999-08-17 Lexmark International, Inc. Method of printing with an ink jet printer to inhibit the formation of a print artifact
JP4193216B2 (ja) * 1997-04-08 2008-12-10 セイコーエプソン株式会社 ドット記録方法およびドット記録装置
US6527364B2 (en) * 1998-05-29 2003-03-04 Canon Kabushiki Kaisha Ink jet recording apparatus and ink jet recording method
US6267467B1 (en) 1998-12-24 2001-07-31 Seiko Epson Corporation Color printing using a vertical nozzle array head
US6416162B1 (en) 1998-12-24 2002-07-09 Seiko Epson Corporation Color printing using a vertical nozzle array head
US6336702B1 (en) * 2000-03-01 2002-01-08 Hewlett-Packard Company Banding reduction in incremental printing, by spacing-apart of swath edges and randomly selected print-medium advance

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EP1642723A3 (de) 2006-11-15
JP2003182066A (ja) 2003-07-03
EP1642723A2 (de) 2006-04-05

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