CA1170205A - Printing head and printing device - Google Patents
Printing head and printing deviceInfo
- Publication number
- CA1170205A CA1170205A CA000352094A CA352094A CA1170205A CA 1170205 A CA1170205 A CA 1170205A CA 000352094 A CA000352094 A CA 000352094A CA 352094 A CA352094 A CA 352094A CA 1170205 A CA1170205 A CA 1170205A
- Authority
- CA
- Canada
- Prior art keywords
- printing
- printing device
- types
- cells
- platen
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
Classifications
-
- 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
- B41J1/00—Typewriters or selective printing mechanisms characterised by the mounting, arrangement or disposition of the types or dies
- B41J1/16—Typewriters or selective printing mechanisms characterised by the mounting, arrangement or disposition of the types or dies with types or dies arranged in stationary or sliding cases or frames or upon flexible strips, plates, bars or rods
-
- 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
- B41J3/00—Typewriters or selective printing or marking mechanisms characterised by the purpose for which they are constructed
- B41J3/01—Typewriters or selective printing or marking mechanisms characterised by the purpose for which they are constructed for special character, e.g. for Chinese characters or barcodes
Landscapes
- Character Spaces And Line Spaces In Printers (AREA)
Abstract
A B S T R A C T
A printing device comprises a platen for supporting items on which text is to be printed, a printing head for printing text, the printing head comprising an array of cells each containing an interchangeable type for printing a respective character, the types being slideable relative to the cells from a rest position to an impression position, the arrangement being such that return of each type towards its rest position from its impression position is effected by its resiliently rebounding from the platen,a trolley carrying the printing head and movable longitudinally relative to the platen between a number of print positions, a print hammer arrangement for propelling the types to their impression positions, a linear motor for causing said relative movement of the platen and trolley and circuitry for controlling the operation of -the impelling means and the drive means. The position of the trolley may be under closed loop control. The printing head may be movably mounted on the trolley for movement in the horizontal and/or vertical directions, optionally by one or more linear motors and optionally with closed loop positional control. Various forms of the printing head, linear motors and print hammers are disclosed.
A printing device comprises a platen for supporting items on which text is to be printed, a printing head for printing text, the printing head comprising an array of cells each containing an interchangeable type for printing a respective character, the types being slideable relative to the cells from a rest position to an impression position, the arrangement being such that return of each type towards its rest position from its impression position is effected by its resiliently rebounding from the platen,a trolley carrying the printing head and movable longitudinally relative to the platen between a number of print positions, a print hammer arrangement for propelling the types to their impression positions, a linear motor for causing said relative movement of the platen and trolley and circuitry for controlling the operation of -the impelling means and the drive means. The position of the trolley may be under closed loop control. The printing head may be movably mounted on the trolley for movement in the horizontal and/or vertical directions, optionally by one or more linear motors and optionally with closed loop positional control. Various forms of the printing head, linear motors and print hammers are disclosed.
Description
1~ 5 DESCRIPTION
"PRINTING HEAD AND PRINTING DEVICE"
This invention relates to printers, particularly, but not exclusively, to those used for printing on stationery and more particularly to printing devices and printing heads~
Large use is currently made of printing devices as peripherals of a wide variety of computer systems. A particular and rapidLy growing use of such devices ïs in the field of computer controlled typing ~ systems, known~as Word Processing systems and the present 1nventlon is particularly but not exclusively concerned with printing devices for;use in such systems.
`~These systems usually comprise, in addition to their~
~printers, an electronic keyboard (to take~the place of the customary~typewriter ~eyboard),~ a v}sua1 dieplay unit (for displaying on~an~electroluminescent screen~
the text~typed),~ ~a central~processor unIt; (~for~running the software programs necessary~for the~manlpu1~at1on~and retrieval of~text to be displayed) and a~disc~storage un1t (for storing standard~text6 and~documents~to~b6 printed). The printer~is usua11y of high quali~ty~6nd~
preci6ion, and is capable of at~l6ast;ma-tching the quality of print of good typewriters. ~ -'.
. , . ~.. . --. . . . . .
' - ' ;
.~
i~7~5 A form of printer widely associated at present with word processing systems is that known as a 'daisy wheel' printer. This name derives from the appearance of its print element which comprises a multiplicity of flexible radial arms, or petals, emanating from a central spindle with dies at their free ends.
Users of Word Processing systems often have difEering requirements as to the various character repertoires that they may wish to be able to print. For 10 example, the provision of a character font incorporating a large proportion of the Greek alphabet might be desirable for a scientific establishment, whereas a quite different font might be required by a commercial concern.
A limitation of the daisy wheel type of printer is that 15 such individual requirements of various users cannot be easily met. Non-standard wheels have to be especially manufactured or individual~petals modified to pr~ovide the desired characters. It is not usually possible for the user to select a speclal repertoire, or~modify the print 20 element, to exactly meet particular requirements.
;According to a first aspect~of the invention, there is provided a printing head comprising means defining an array of cells; a~plural1ty~of individually replaceable types for printing respective characters, ~25 each of the types being indlviùual~ly in~terchangeably mounted in, guided by,~and freely slidable relative to z~s respective ones of the cells from an extended impression position towards a retracted rest position, the types during printing being free of mechanical connection with the array defining means other than their slidable mounting in the cells thereof, the printing head being mountable .in a printing device so that each of the types is movable between its rest position and its impression position by a component of the printing device, the arrangement of the cells and type in the printing device 10 being such that each type is returnable towards its rest position from its impression position by resiliently rebounding from a platen.
This aspect of the invention also provides a printing head comprising: means defining an array of : 15 cells; a plurality of individually replaceable types for : ~ printing respective characters, each of the types being individually interchangeably mounted in, guided by, and freely slidable relative to respective ones of the cells from an extended impression:position towards~ a retracted ~: 20 rest positlon, the printing head being mountable in a ~: ~printing:device so that each of the:types;~is movable between 1ts~rest position and its impression~ position by a component of the printing device,~the arrangement of : the~cells and;types in the printing device being;:such 25 that each type is returnable towards its~rest position from its impression position by resi]lently rebounding ::
:: ~ :
7~2~5 from a platen.
A second aspect of the present invention provides a printing device comprising: a platen for supporting items on which text is to be printed, the platen having an axis; a printing head for printing text, the printing head comprising means defining an array of cells having axes which are at least approximately horizontal and a plurality of individually replaceable types for printing respective characters, the 10 types being interchangeably mounted in, guided by, and freely slidable in respective ones of the cells from an extended impression po,sition towards a retracted rest position, the types being free of mechanical connection with the array defining means other than their slidable 15 mounting in the cells thereof; a support carrying the printing head and movable longitudinally relative to the platen between a number of print positions, the reIationship between the support and the printing head being such that for each type, on its impact with the 20 platen, the force tending to restore it from ~ts impression~position towards its rest position derives substantially solely from its resiliently impacting with ~ the platen; means for propelling the types~to their : impression positions; and drive means for causing said 25 relative movement of ~he platen and support.
This aspect of the invention also provides a , :
.......
,, . , ~
~7~ 5 printing device comprising: a platen for supporting items on which text is to be printed, the platen having an axis; a printing head for printing text, the printing head comprising means defining an array of cells having axes which are at least approximately horizontal and a plurality of individually replaceable types for printing respective characters, the types being interchangeably mounted in, guided by, and freely slideably mounted in respective ones of the cells from an extended impression 10 position towards a retracted rest position; a support carrying the printing head and movable longitudinally relative to the platen between a number of print positions, the relationship between the support and the printing head being such that for each type, on its 15 impact with the platen, the force tending to restore it from its impression position towards its rest position derives predominantly from its resiliently impacting with :~ the platen,:means for propelling the types to thelr : impression positions; and drive means for causing said 20 relative move~ent of the platen~and support.
; By "substantially solely"~we intend to encompa~ss both situations where the re=ilient rebound is the sole meaning and where there may~be~other 'isecond;
~; ~ order" effects~such as the tension;of the ribbon which 25 although strictly speaking do make a contribution to the restoring force, ss a~practical matter thelr contribueion may be neglected.
:
- ~
:
z~s It will thus be appreciated that the present invention is based on a totally different concept from previous proposals, namely to rely on the resilient impacts of the types with the platen as the sole or, at least the predominant means by which the types are returned from their impacts with the platen. In daisy wheel type printers, for example, the restoring force is intended to be supplied by the resilience of the radial arms; likewise there are prior printers with sliding 10 types where the types are connected to return springs or --retractable magnets. Common to the various conventional printers is the idea that the types are acted upon by some specifically provided return means which biases them towards their rest positions. A consequence of this is 15 that the types tend not to be readily individually replaceable by non-skilled users of the printer because for example, lndividual return springs have to be disconnected and reconnected or the types cannot be individually replaceable at all as is the case with the ~20 daisy wheel. In the present invention, the idea is to rely on the resilient impacts o the types~to return them and so the types do not need to~be provided with~
individual return means. This enables the~types to be readily replaceable one by one, and~the use of~ a compact 25~print element.
:
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to opposite faces thereof. In another form the cells may be defined by pairs of aligned apertures in two spaced apart lattices or grids.
l'he cavities ('cells') of the honeycomb are not necessarily hexagonal in cross-section, indeed in a preferred embodiment of the invention the cavities and types are of rectangular cross-section. However, their cross-ection may also take other forms which advantageously ensure the types are positioned the correct way up, in addition to preventing rotation. The types may protrude from both sides of the honeycomb and may be biased towards a home position away from the stationery. It will be appreciated that the cavities of the honeycomb may each be filled by individual types I5 bearing the desired characters so fulfilling the requirements of the user of the printer. An ink or carbon ribbon may be located in between the honeycomb and the stationery for providing an impression of~the print die.
~ Printers of the daisy-whee1 kind make use of a trolley to carry the print mechanism and element.
The trolley is free to slide aIong bars positioned parallel to and in front of the platen of the printer.
Stationery is fed around the platen using pinch rollers as in a typrewriter. In some examples, motion is imparted to the trolley by means o~ a direct current ',, , ~
, . . .
, , 117~35 ,~ _ servo motor, cable and pulley arrangement. Information on the position of the trolley at any moment is obtained from an optical encoder disc mounted on the shaft of the motor. When movement of the trolley is required, a signal is sent to the motor, the force and polarity of which is determined by the extent and direction of the required displacement. Comprehensive compensation circuits allow ~or variations in performance of the motor servo loop system. The support in embodiments of the present invention may comprise such a trolley mounted for sliding movement longitudinally of the plat~n by a guide rail arrangement.
Relative motion of the platen and the printing head of the printer of ;the present invention is achieved by use of a linear motor so controlled as to enable the platen and printing head to be arrested, relative tc one another, in any desired prlnt position. The linear motor may be a stepping motor or an alternating current linear motor.
~ To obtain linear motor action from~an alternating current, two or more such currents, each out of phase with the other, are applied to;coils lain along the direction in which motion is to be - imparted. To increase their ef~ect, the coils are normally placed in slots in a ferrous stator. A
:
conducting material, such~as aluminium, when placed :
: . -.
, ,:.
-~7tl~D5 adjacent to the coils, experiences induced currents~
These in turn create magnetic fields which react with those created initially by the applied currents, so producing thrust. When lateral constraints are S applied, the thrust, in general, is in the direction of the magnetic river created by the coils.
In an optional feature of the invention in which propulsion is imparted to the printing mechanism trolley by means of such an alternating current linear motor, both the amplitude and phasing of alternating currents applied to accelerate the trolley may be determined on the basis of the required extent and direction of the displacement thereof to be effected, and braking of the trolley is achieved by reversing the direction of magnetic flux created by the motor and similarly regulating the amplitude and phasing of the now decelerating current~s according to the speed and position of the trolley relative to~its dest1nation.
~ In one version, a two phase supply may be utilized to~ feed a two-phase A.C. llnear motor, with the direction and amplitude of thrust~imparted to the trolley being~determlned~solely~by~the relative displacement of one supply xelat~ive to the other.
A transducer arrangement may be provided~
:
"PRINTING HEAD AND PRINTING DEVICE"
This invention relates to printers, particularly, but not exclusively, to those used for printing on stationery and more particularly to printing devices and printing heads~
Large use is currently made of printing devices as peripherals of a wide variety of computer systems. A particular and rapidLy growing use of such devices ïs in the field of computer controlled typing ~ systems, known~as Word Processing systems and the present 1nventlon is particularly but not exclusively concerned with printing devices for;use in such systems.
`~These systems usually comprise, in addition to their~
~printers, an electronic keyboard (to take~the place of the customary~typewriter ~eyboard),~ a v}sua1 dieplay unit (for displaying on~an~electroluminescent screen~
the text~typed),~ ~a central~processor unIt; (~for~running the software programs necessary~for the~manlpu1~at1on~and retrieval of~text to be displayed) and a~disc~storage un1t (for storing standard~text6 and~documents~to~b6 printed). The printer~is usua11y of high quali~ty~6nd~
preci6ion, and is capable of at~l6ast;ma-tching the quality of print of good typewriters. ~ -'.
. , . ~.. . --. . . . . .
' - ' ;
.~
i~7~5 A form of printer widely associated at present with word processing systems is that known as a 'daisy wheel' printer. This name derives from the appearance of its print element which comprises a multiplicity of flexible radial arms, or petals, emanating from a central spindle with dies at their free ends.
Users of Word Processing systems often have difEering requirements as to the various character repertoires that they may wish to be able to print. For 10 example, the provision of a character font incorporating a large proportion of the Greek alphabet might be desirable for a scientific establishment, whereas a quite different font might be required by a commercial concern.
A limitation of the daisy wheel type of printer is that 15 such individual requirements of various users cannot be easily met. Non-standard wheels have to be especially manufactured or individual~petals modified to pr~ovide the desired characters. It is not usually possible for the user to select a speclal repertoire, or~modify the print 20 element, to exactly meet particular requirements.
;According to a first aspect~of the invention, there is provided a printing head comprising means defining an array of cells; a~plural1ty~of individually replaceable types for printing respective characters, ~25 each of the types being indlviùual~ly in~terchangeably mounted in, guided by,~and freely slidable relative to z~s respective ones of the cells from an extended impression position towards a retracted rest position, the types during printing being free of mechanical connection with the array defining means other than their slidable mounting in the cells thereof, the printing head being mountable .in a printing device so that each of the types is movable between its rest position and its impression position by a component of the printing device, the arrangement of the cells and type in the printing device 10 being such that each type is returnable towards its rest position from its impression position by resiliently rebounding from a platen.
This aspect of the invention also provides a printing head comprising: means defining an array of : 15 cells; a plurality of individually replaceable types for : ~ printing respective characters, each of the types being individually interchangeably mounted in, guided by, and freely slidable relative to respective ones of the cells from an extended impression:position towards~ a retracted ~: 20 rest positlon, the printing head being mountable in a ~: ~printing:device so that each of the:types;~is movable between 1ts~rest position and its impression~ position by a component of the printing device,~the arrangement of : the~cells and;types in the printing device being;:such 25 that each type is returnable towards its~rest position from its impression position by resi]lently rebounding ::
:: ~ :
7~2~5 from a platen.
A second aspect of the present invention provides a printing device comprising: a platen for supporting items on which text is to be printed, the platen having an axis; a printing head for printing text, the printing head comprising means defining an array of cells having axes which are at least approximately horizontal and a plurality of individually replaceable types for printing respective characters, the 10 types being interchangeably mounted in, guided by, and freely slidable in respective ones of the cells from an extended impression po,sition towards a retracted rest position, the types being free of mechanical connection with the array defining means other than their slidable 15 mounting in the cells thereof; a support carrying the printing head and movable longitudinally relative to the platen between a number of print positions, the reIationship between the support and the printing head being such that for each type, on its impact with the 20 platen, the force tending to restore it from ~ts impression~position towards its rest position derives substantially solely from its resiliently impacting with ~ the platen; means for propelling the types~to their : impression positions; and drive means for causing said 25 relative movement of ~he platen and support.
This aspect of the invention also provides a , :
.......
,, . , ~
~7~ 5 printing device comprising: a platen for supporting items on which text is to be printed, the platen having an axis; a printing head for printing text, the printing head comprising means defining an array of cells having axes which are at least approximately horizontal and a plurality of individually replaceable types for printing respective characters, the types being interchangeably mounted in, guided by, and freely slideably mounted in respective ones of the cells from an extended impression 10 position towards a retracted rest position; a support carrying the printing head and movable longitudinally relative to the platen between a number of print positions, the relationship between the support and the printing head being such that for each type, on its 15 impact with the platen, the force tending to restore it from its impression position towards its rest position derives predominantly from its resiliently impacting with :~ the platen,:means for propelling the types to thelr : impression positions; and drive means for causing said 20 relative move~ent of the platen~and support.
; By "substantially solely"~we intend to encompa~ss both situations where the re=ilient rebound is the sole meaning and where there may~be~other 'isecond;
~; ~ order" effects~such as the tension;of the ribbon which 25 although strictly speaking do make a contribution to the restoring force, ss a~practical matter thelr contribueion may be neglected.
:
- ~
:
z~s It will thus be appreciated that the present invention is based on a totally different concept from previous proposals, namely to rely on the resilient impacts of the types with the platen as the sole or, at least the predominant means by which the types are returned from their impacts with the platen. In daisy wheel type printers, for example, the restoring force is intended to be supplied by the resilience of the radial arms; likewise there are prior printers with sliding 10 types where the types are connected to return springs or --retractable magnets. Common to the various conventional printers is the idea that the types are acted upon by some specifically provided return means which biases them towards their rest positions. A consequence of this is 15 that the types tend not to be readily individually replaceable by non-skilled users of the printer because for example, lndividual return springs have to be disconnected and reconnected or the types cannot be individually replaceable at all as is the case with the ~20 daisy wheel. In the present invention, the idea is to rely on the resilient impacts o the types~to return them and so the types do not need to~be provided with~
individual return means. This enables the~types to be readily replaceable one by one, and~the use of~ a compact 25~print element.
:
, '. ~ ' .
~L~7~2~5 ,~
to opposite faces thereof. In another form the cells may be defined by pairs of aligned apertures in two spaced apart lattices or grids.
l'he cavities ('cells') of the honeycomb are not necessarily hexagonal in cross-section, indeed in a preferred embodiment of the invention the cavities and types are of rectangular cross-section. However, their cross-ection may also take other forms which advantageously ensure the types are positioned the correct way up, in addition to preventing rotation. The types may protrude from both sides of the honeycomb and may be biased towards a home position away from the stationery. It will be appreciated that the cavities of the honeycomb may each be filled by individual types I5 bearing the desired characters so fulfilling the requirements of the user of the printer. An ink or carbon ribbon may be located in between the honeycomb and the stationery for providing an impression of~the print die.
~ Printers of the daisy-whee1 kind make use of a trolley to carry the print mechanism and element.
The trolley is free to slide aIong bars positioned parallel to and in front of the platen of the printer.
Stationery is fed around the platen using pinch rollers as in a typrewriter. In some examples, motion is imparted to the trolley by means o~ a direct current ',, , ~
, . . .
, , 117~35 ,~ _ servo motor, cable and pulley arrangement. Information on the position of the trolley at any moment is obtained from an optical encoder disc mounted on the shaft of the motor. When movement of the trolley is required, a signal is sent to the motor, the force and polarity of which is determined by the extent and direction of the required displacement. Comprehensive compensation circuits allow ~or variations in performance of the motor servo loop system. The support in embodiments of the present invention may comprise such a trolley mounted for sliding movement longitudinally of the plat~n by a guide rail arrangement.
Relative motion of the platen and the printing head of the printer of ;the present invention is achieved by use of a linear motor so controlled as to enable the platen and printing head to be arrested, relative tc one another, in any desired prlnt position. The linear motor may be a stepping motor or an alternating current linear motor.
~ To obtain linear motor action from~an alternating current, two or more such currents, each out of phase with the other, are applied to;coils lain along the direction in which motion is to be - imparted. To increase their ef~ect, the coils are normally placed in slots in a ferrous stator. A
:
conducting material, such~as aluminium, when placed :
: . -.
, ,:.
-~7tl~D5 adjacent to the coils, experiences induced currents~
These in turn create magnetic fields which react with those created initially by the applied currents, so producing thrust. When lateral constraints are S applied, the thrust, in general, is in the direction of the magnetic river created by the coils.
In an optional feature of the invention in which propulsion is imparted to the printing mechanism trolley by means of such an alternating current linear motor, both the amplitude and phasing of alternating currents applied to accelerate the trolley may be determined on the basis of the required extent and direction of the displacement thereof to be effected, and braking of the trolley is achieved by reversing the direction of magnetic flux created by the motor and similarly regulating the amplitude and phasing of the now decelerating current~s according to the speed and position of the trolley relative to~its dest1nation.
~ In one version, a two phase supply may be utilized to~ feed a two-phase A.C. llnear motor, with the direction and amplitude of thrust~imparted to the trolley being~determlned~solely~by~the relative displacement of one supply xelat~ive to the other.
A transducer arrangement may be provided~
:
2~5 for detecting the relative posltion of the trolley and~
platen for posltional~feedback. ~For~example, an :.:
'1 ::
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optical encoder grill may be located along the length of the linear motor and provide, by means of transducers mounted on the trolley, information on the position thereof to circuits controlling the alternating curxents supplied to-the motor. The grill could of course be located on the trolley and the transducers adjacent the path of the trolley.
There may be defined a plurality of detents in the relative positioning of the trolley and platen, the spacing of the detents corresponding to the spacing between adjacent character positions of the printed text or an integral sub multiple thereof. Where a transducer arrangement is provided for detecting the relative position of the trolley and platen, the detents may be defined electronically by the control circuitry associated with the drive means.
In a particular form of the invention, stationery is fed around a fixed-type platen and is guided by friction pinch rollers. The stationery thus remalns substantially stationary relative to the sides of the body of the printer. Feed action lS
effected by means of a split phase stepper motor.
In a feature of this particular form of the invention, the propelling means of the print mechanism is mounted in a fixed position on the slideable trolley while the honeycomb housing the type , ,.
. . . ' .
~7~ S
is supported on the trolley by a bracket which is movable relative thereto the extent and direction of movement being effected by electromagnetic forces created by surrounding field coils, and the arrangement being such that, in use, the displacement of the ho.neycomb relative to the propelling means and the trolley relative to the stationery determine respectively the characters to be printed and their sequence~
In one version the bracket supporting the honeycomb is in the form of a pyramid like frame with the honeycomb forming its base, and lies, in its rest position, substantially perpendicular to the platen along the breadth of the trolley. The type propelling means is located within the space within the frame.
~wo palrs of field coils act on magnets mounted on each of the four sides of the frame and control of the deflection of the bracket by the currents ~flowing in the coils is governed by servo-loop:~signals. These are :
provided by optical-encoder grills mounted on the : bracket moving relative to transducers mounted on the trolley, or vice-versa. In one form, the honeycomb has substantially the same number of t~pe-receiving cavities width-wise as it does in depth~ It will be appreciated, by way of example, for~ten pitch type (ten printed characters to an inch), -the maximum :
' ' . ~ .
2~S
1~
g - deflection from its rest position to an extreme print position only requires a three-quarterinch horizontal and vertical movement of a one and one half inch square honeycomb housing one hundred characters.
S In another version of this embodiment of the invention, the bracket supporting the honeycomb moves within a further bracket affixed to the trolley and is guided therein by gimbals or grooves giving freedom in the horizontal and vertical senses relative to the platen of the printer. Deflection of the first bracket and therefore the honeycomb to a desired print position is effected by means of solenoids, or small linear motors, acting on the gimbal and bracket assembly. The honeycomb itself may be constructed from, or is clad by, an electrically conductive material, and the linear motors themselves act directly upon the honeycomb and/or its cladding to move the honeycomb to the desired position. In a preferred form the sides of the honeycomb itself are fashioned from an aluminium alloy.~
; ~n printers of the daisy wheel kind, sophisticated servo-mechanisms are required to arrest accuratèly a daisy wheel in a given print position, there being usually nearly one hundred petals - and~
therefore stop positions - on most daisy wheels.
~7~2~S
In a further feature, also relating to the use of linear induction motors to move the honeycomb, a servo-mechanism utilized for controlling the position of the honeycomb relative to the print hammer is able so to do by means of impulses received -from a combination of toothed notches on the honeycomb and/or its cladding moving relative to fixed electromagnetic sensors, or vice-versa. The notches may correspond directly to the position of rows and columns of types, thus the counting of impulses created by movement of the notches relative to the sensors in the vertical and or horizontal directions establishes the precise position of a given type, relative to the hammer. It will be appreciated that for a ten square honeycomb accommodating one hundred types, only ten stop positions are required respectively in`the hor`izontal and vertical senses.
In a further feature~ the honeycomb is moved relatlve to the p~rint ha~ner by stepping motors.
Energisatlon of the colls of the s~tepping motors in a given sequence attracts pole~pieces~embedded~within the honeycomb,;and thus~ the~honeycomb~ltself,~to stable detent positions, these positlons corresponding to individual rows and;~columns~withln the honeycomb.
No servo-mechanism is required in this arrangement.
Furthennore, in a further scheme in~which no servo-:
`' . ,~
`, ~`, ' , ' ~7`~2Ç~S
mechanism is required, rotary stepper motors takethe place of the linear stepping motors, and position the honeycomb in the vertical~horizontal senses by means of pinions engaging racks affixed to the honeycomb. Imparting an appropriate number of stepping pulses to each motor locates the selected type opposite the print hammer.
Referring now to the honeycomb itself, in use a type returns towards its original, rest position in its cell - after having been impelled towards the platen of the printer by the propelling means - as a result of bouncing off the resilient platen. In order to assist this return the honeycomb as a whole may be inclined away from the vertical and away from the upper portion of the platen, but in such a way that the face of the honeycomb remains substantially perpendicuIar to a radius of the platen, the arrangement being such that gravltational forces aid the said bouncing effect~restoring type to its original position within ltS cavity.
An important aspect of the inventlon is the interchangeability of typ~s within the honeycomb.
Any chæacter font desired by a~particular user can thereby be provided up to the capacity of the honeycomb. In practice, easy lnterchangeability~
~ is desirablo, but not at the expeuse of types slipping ., . . ~
1~71D2~5 S
from their respective positions during printing operation and during removal of the honeycomb from the printer. A removable retaining member may be provided to retain the types in their cells while permitting movement between their rest and impression positions. Thus grooves on the honeycomb slideably accommodate, on one of its open surfaces, a slotted base plate, the slots of the base plate engaging - -corresponding slots along the body of each type, there being sufficient freedom to permit each type to impinge against the platen when impelled theretowards by the print hammer. Thus, in this arrangement, the slotted base plate prevents types from inadvertently falling from the honeycomb, but, on removal from its supporting grooves, allows the types to be withdrawn and exchanged.
The invention further providQs a word processor~incorporating a printi~ng devlce embodying the second aspect of the present invention.
The invention will now be~described in~more detail, by way of examp1eJ with reference to~the~
accompanying~drawings in which:
Figure 1 is a somewhat schematic perspective view of part of a printing device embodying the present invention;
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Figure 2 is an illustration showing to an enlarged scale the print head of the printer of Figure l;
Figure 3 is a block circuit diagram showing the derivation of control signals used within the printer of Figure 1, -Figure 4 is an illustration showing yet another embodiment of printing device according to the present invention, 10Figure 5 shows part of a printing device embodying the invention and including linear motors acting on a honeycomb printing head, Figure 6 is an illustration showing a honeycomb printing head and position sensor embodying the present invention,:
Figure 7 shows linear stepping motors acting on a honeycomb printing head embodying:the present invention; : : :
Figure 8 shows:part of a~printing:device ~
embodying the invention in~luding a honeycomb printing : head;
Figure 9 shows detached, constituent parts together comprising a honeycomb prlnting:~h:ead~embodying :
the present invention~
Figure 10 shows waveforms~applied to a linear : motor used within a printer a~cording to Figure l;
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Figure 11 shows a phase control network for regulating supplies to the linear motor; and Figure 12 is a cross-sectional view of a print hammer of an embodiment of the present invention.
Referring to Figure 1, a printing device according to the invention is generally designated 10 and includes a platen 11 embraced circumferentially along part of its length by stationery 12. The coil of an alternating current linear induction motor 13 is mounted on the base of the printer, and is used to propel a trolley 14 in a horizontal sense from left to right and vice-versa, as indicated by the arrow. The trolley is held above and guided along the ~ motor by means of tongues, two of which are shown at 15 and 16, engaging grooves 17 running along the :
motor's length. A print mechanism 18 is supported on the trolley 14 and includes a suspended~honeycomb print head 19 and means~(not shown3 for mcving the head relative to an electromagnetic hammer 20, also~ unted 20 ~on the trolley. Information on the~position of the ~trolley and its movement is~obtained from a-transducer 21 mounted thereon and~arranged to scan an optical encoder grill 22 affixed to~-t~e linear motor. ~A 'snake' :
23 attached at one end to the trolley and at the ~ ~ :
25~ other to the base of the printer is used to convey and protect signal cables connected to the transducer and : ~
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Ig ,~ _ other components of the print mechanism.
The print head 19 of the printer is now described with reference to Figure 2 which shows from the rear such a head but to an enlarged scale. The head consists of a symmetrical open-sided honeycomb-like array of a multiplicity of cavities. Each of the cavities is, in this example, of square cross-section and is occupied by a slideable type, two of which are shown protruding, for clarity, from the rear face of the hoenycomb at 24. There is no physical bond between each ty e and the surrounding honeycomb frame, with the exception of a type-retainlng bracket to be hereinafter described in more detail~ mus each type may be directly extracted from the honeyaomb on removal of the said bracket. Each type ends in a prin-t die, as shown for example at 25. In practicé, lips on each type 26~, not shown, prevent protrusion o~ the types from the;plane of the rear face of the~element.
In~one example, the honeycomb~is constructed~from~
lightweight plastics, but has attached to its rear face a ferromagnetic lattice. m e types may be magnetised to aid their retention~in the honeycomb. ~The lattice may be magnetised instead.~ ~
~ ~ The mode of~operation of the pri~nting device of Figures 1 and 2 is as follows:-,, - ~ .
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The linear motor first causes the trolley to move to the first desired print position. Whilst this is happening, the honeycomb is deflected by electromagnetic forces acting on its suspension unit to a position which brings the desired t~pe opposite the electromagnetic hammer 20 (see Figure 1). As soon as the trolley stops, and the honeycomb is positioned, the hammer is fired and the selected type slides along its cavity sufficiently to impinge, through an ink ribbon (not shown) onto the stationery 12 mounted within the printer, thereby leaving an inked impression.
The type reiurns to its cavity as a result of bouncing off the resilient platen, and may also be aided in this respect by the ink ribbon which may be kept appropriately tensioned.
As shown in Figure 12, in a further version each type may contain in its rear end a ferromagnetic core. The hammer itself is magnetised,~and as the hammer and type return from the platen as a result ;~ 20 of bounclng there off, the attractlon exerted by the hammer on the core within the type ensures the type returns to ltS cavity.~ The hamrner by virtue of~its return rnomentum, breaks away from the type, once the protruding Iips~26 prevent~further movement thereof, so becoming ready for the next impact~a (The hammèr also returns, in part, as~a result~of the type bouncing ~ ' ., .
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-~:~7~5 off the platen, the 'bounce' being transmitted to the body of the hammer from the body of the type. A
return spring may aid the return of the manner). The trolley is then moved by the linear motor to the next desired position, the honeycomb is repositioned, and the process repeated~ Thus the desired sequence of characters is printed. The honeycomb may be detached from the suspension unit by the operator using the printer. m e cavities of the honeycomb may then be filled by types corresponding exactly to the operator's particular requirements, so providing a very flexible character repertoire. Furthermore, with regard to wear, only those types in most frequent use need be replaced, rather than changing the entire lS element. (It will be appreciated ~rom the die illustrated at 25 in Figure 2 that the effective print portion may have considerable body, so reducing necessity ~or frequent replacement.) The method of imparting motion to the trolley,~ and its control, will~now be described with :
reference to Figures lO~and 11.
- In one embodiment, a two-phase linear induction motor is employed~ to move~the said trolley.
A phase control network, responsive to trolley positioning commands recei~ed by the printer, regulates ~whether phase a leads b, or b leads a, (see Figures . ..
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10 i and ii), this thus determines the direction of thrust. In addition to this, the amplitude of thrust exerted by the linear motor on the trolley is similarly detennined, being dependent on the extent to which one phase is made to lead the other. Thus, for a corresponding pole pitch, a maximum thrust is experienced with a ~2 radians out of phase with b, whereas no thrust is experienced with the two phases superimposed (see Figure 10 iii). The phase control network need therefore only regulate the relative phasing of the two supplies a and b, to both control the direction of thrust imparted to the trolley and its amplitude, so providing means conveniently responsive to a servo-loop control system for controlling the position of the trolley.
A convenient form of phase control network may take that shown in Figure 11O In this, regulation of the gating currents to four thyristors 126, 127, 128 .
~ and 129, controls the degree of~direct and phase- :
displaced alternating current supplied to each coll of the motor.: Thus, with 126 and~l29~switched on,~ fu11 : thrust will be experienced in one dlrection:and, conversely, switching on 127 and 128 causes full thrust to be experienced in the opposite direction~ Intermediate :
degrees of thrust in each:direction are obtained by appropriately controlling the flr1ng periods of the . . . ., . - . ~ . .
, ~7~2~5 various thyristors.
To obtain, however, carefully regulated acceleration and deceleration of the trolley, a modified embodiment of the invention makes use of control of both the amplitude of the applied currents and also their phase displacements. An example of such control is now described with reference to Figure 3.
Suppose a displacement D is to be effected, D being represented by a multiple bit binary word indicating the number of gradationst~ be traversed by the transducer 21 over the optical encoder grill 2 (se~ Figure 1). The start position of the trolley Ps is first added in a binary adder to ~, to arrive at the finishing position, Pf~ (Ps is derived from an internal binary counter, Pa~ which permanently follows the output of the transducer). Once Pf lS obtained, ~
the absolute mid-point position Pm is~also calculated;
see equation l~in Figure 3. A digital to analogue coverter, 28,~ then lnterprets these~signals to regulate khe amplitude,;A, of the supplies a and b, according to ~the extent of the dispLaaement to be ~effected. Thus the accelerating thrust, Aa is~made proportional to a combination of the initial difference between Ps and Pm, and thereafter~to the difference ; between the absolute positi~n of the trolley, ' ~ ' :
~7~ S
~3 Pa, and, say, the mid-point position Pm. (Note, for very small displacements, a minimum value of Aa is applied to overcome static friction.) As the mid-point is reached, the accelerating thrust. is substantially reduced. However, as soon as the mid-point is crossed, the decelerating thrust Ad is made sufficient to counter the velocity imparted to the trolley, and is therefore determined partly by the difference between Pm and Pf (reflecting the velocity imparted by Aa), 10 and also, towards the end of the trolley's travel, by -the difference between Pa and Pf. Suitably regulating the degree to which these two quantities act on the deceleration ensures the trolley actually arrives at its destination. Simultaneous to the reyulation of the amplitude of thrust A, Pm and Pa are fed to a comparator, 29, to determine the phase relationship -between a and b~and thus the direction of thrust, so giving rise, effectively, to the two components Aa and Ad. A component of the signal A is~also fed to the comparator to further influence the phase relationship accordlng to the thrust required, as described earlierO The use of absolute reference positions,~such~as Ps and Pa/ enables comparison to be made with predetermined`reference positions, so safeguarding agalnst such eventualities as displacements being effected which would otherwise result in the :
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trolley crashing into end-stops mounted on the printer.
It will be appreciated that the foregoing is given by way of example for one particular embodiment of the invention only. Many methods of servo-control of the movement of the trolley are possible.
In a feature of the invention, once the honeycomb is positioned and the print hammer is fired, energisation of the hammer solenoid causes attraction onto it of the ferromagnetic rear face of the honeycomb, so preventing relative movement therebetween while the firing pin of the hammer propels the chosen type forward.
The natural resilience of the support frame detaches the honeycomb from the hammer solenoid once it is de-energised. It will be appreciated that the most commonly used letters within a given character repertoire may be grouped centrally. Thus, for example, :
all but one of the lower case letters of the English~
alphabet will occupy a five square matrix, so requiring - in the~maln -~only a small deflectlon~of the honeycomb from its rest position while printing.
Referring to Figure 5, two-phase linear induction motors depcited at I10 and lll are shown acting on a honeycomb printing head 19, and a thrust plate 113 respectively. The print~head is free to move in a vertical sense relative to the motor 110.
The linear notor 110 acts directly on the print ., :
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element l9, which itself is constructed from an aluminium alloy, to establish vertical movement thereof.
The thrust plate 113 is affixed to the base of the motor llO, and is acted upon by the motor 111 to cause horizontal displacements of the honeycomb and motor llO
combination. In use, appropriate phasing of currents to the two motors thereby establishes both horizontal and vertical movement of the honeycomb to any desired -position. Third and fourth motors may be provided opposite those shown at lO and ll to increase the thrust exerted upon the honeycomb and thus the speed at which a desired position is reached. The honeycomb may he supported by tongues emerging therefrom and slideably engaging grooves 14 in the linear motor llO.
~eferring to Figure 6 in an alternative arrangement, teeth 115 are shown protruding from a lateral face of the print element l9. A fixed ~ -electromagnetic sensor 116 is positioned adjacent to the teeth~for their detection~ A similar arrangement (not shown) exists on the horizontal ~ace~of the honeycomb,~or~the thrust plate 113. ~The;position of the honeycomb~relative to the linear tor (shown in Figure S) is established by detectlon of the number of teeth passing either sensor7 The teeth may each :
correspond to each row~and or column of types housed within the honeycomb, the axxangement being such that .
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a servo-mechanism circuit controlling the action of the linear motors ensures the required displacement of the honeycomb to a desired position by counting the number of teeth passing each sensor. Alternating currents are passed through the coils of the sensors, and the horizontal/vertical teeth of the honeycomb are detected by virtue of the change they effect in the inductance of the sensor/tooth combination, and thus the current passing through the respective sensor coil(s).
An alternative method of effecting movement of the honeycomb is now described with reference to Figure 7. Instead of using linear induction motors, linear stepping motors are employed~ These are shown, . .
schematically, at 117 and 118. Magnetised cores 119 and 120 are embedded in the sides of the honeycomb.
The sequence of North/South pole magnetisation of the cores is such that suitable energisation .
sequences of the coils of the stepping motors causes horizontal and vertical move~ent of the :
honeycomb to a desired position. One or other of the~
motors 117, 118 of course moves with the honeycomb during actuation of the~other motor 118 or 117.
In this arrangement, st~ble detent positions of the cores opposite;the poles of the stepping motors correspond to individual rows and columns~of types ~: ' ~ ' :
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within the honeycomb, thus no servo-mechanism is required.
As described above, the types, having first been impelled forwards, return to their cavities within the honeycomb as a result of bouncing off a resilient platen of the printer. In a further feature, the honeycomb itself, see reference 19 of Figure 8, is inclined to the vertical. The inclination is such that the rear face of the honeycomb forms an acute angle with the trolley 14 of the printer on which the honeycomb/motor assemblies are mounted. The honeycomb remalns however substantially tangential to the platenO
In this arrangement, types are impelled lS forwards, as also described earlier, by an electromagnetically propelled hammer 122. (~he hammer is a1so inclined relative to the trolley, being at ~r1ght angles to the rear face of the honeycomb.) The effect of the inclination~of the honeycomb;, is ~o ~
enhance the~restitution of types into ~heir~cavi~ies, by virtue~of~ihe gravitational component acting thereon.
~ v During printing operations, or during the exchange of honeycombs,~it~is~important to prevent types from escaping from their cavlties.~
However, an lmportant aspect of~the invention is the .
interchangeability of types~ To fulfil these .,~ :
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requirements, grooves 123 on the honeycomb, 23, see Figure 9, slideably accommodate, on one of its open surfaces, a slotted base plate 124. The slots of the base plate engage corresponding slots 125 along the body of each type. The longitudinal length of the slots 25 provides sufficient freedom to permit each type to impinge against the platen, and to bounce back, but by virtue of their engagement with the base plate, prevents types from falling out, or bouncing back too far~ If it is required to exchange types, the base plate may be withdrawn from its grooves, so freeing them for this purpose.
In yet a further embodiment of the invention, for applications where high speed print is required, movement of the honeycomb and its print types is effected in the vertical sense only, see Figure 4~
In this example, a small stepper motor 51 15 used by means of a crank arrangement 52, to raise and lower the honeycomb OD guide rods~53 and 54 affixed to the ;
base of the trolley 30. A circular optical encoder grill 55 is mounted on the axls of the motor and serves, in conjuction with a transducer 56, to provide information on the position of;the honeycomb.
Mounted above the motor and directly in front of the honeycomb is a battery of electromagnetic hammers ~
(shown offset for clarity at 57), one for each column ` ":
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~7~2~)5 "2q - ~6 of cavities in the honeycomb. (In an alternative arrangement, the honeycomb is raised and lowered by a servo-controlled linear motor, or by a stepper motor.) In this arrangement, when a sequence of characters is to be printed, control circuitry regulates the movement of the trolley such as to bring the column containing the desired type to the desired print position. At the same time, the stepper tor raises or lowers the honeycomb to the correct height and the appropriate hammer is then fired. It will be appreciated that for a honeycomb twelve cavities wide, the motor need only oscillate between two adjacent positions to present nearly all the lower case characters of this alphabet to the battery. Furthermore, by comparing the character~string to be printed with the corresponding lateral position of the honeycomb, it will frequently be possible to fire more than one han~ner at a tlme, so improving the rate of print. When this occurs, to avoid 'back-stepping', the chaxacters~
may be printed not necessarily one after the other~ ;
For example, the honeycomb may be so positioned that a letter or letters of a second word may be printed whiIe a first word is being formed, and so on. The extent to which this occurs is of course determined by any given character sequence, and may be optimised by comparison registers within the printer controlling "
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the motion of the trolley and honeycomb relative to the stationery~ The positioning of the hammers and honeycomb relative to the trolley may be adapted to be at right angles to the arrangement shown in Figure 4 for oriental printing requirements.
It will be appreciated that the various modifications described above to -the basic form of the printing device of Figure 1 may be used alone or in various appropriate combinations with one another.
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platen for posltional~feedback. ~For~example, an :.:
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optical encoder grill may be located along the length of the linear motor and provide, by means of transducers mounted on the trolley, information on the position thereof to circuits controlling the alternating curxents supplied to-the motor. The grill could of course be located on the trolley and the transducers adjacent the path of the trolley.
There may be defined a plurality of detents in the relative positioning of the trolley and platen, the spacing of the detents corresponding to the spacing between adjacent character positions of the printed text or an integral sub multiple thereof. Where a transducer arrangement is provided for detecting the relative position of the trolley and platen, the detents may be defined electronically by the control circuitry associated with the drive means.
In a particular form of the invention, stationery is fed around a fixed-type platen and is guided by friction pinch rollers. The stationery thus remalns substantially stationary relative to the sides of the body of the printer. Feed action lS
effected by means of a split phase stepper motor.
In a feature of this particular form of the invention, the propelling means of the print mechanism is mounted in a fixed position on the slideable trolley while the honeycomb housing the type , ,.
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is supported on the trolley by a bracket which is movable relative thereto the extent and direction of movement being effected by electromagnetic forces created by surrounding field coils, and the arrangement being such that, in use, the displacement of the ho.neycomb relative to the propelling means and the trolley relative to the stationery determine respectively the characters to be printed and their sequence~
In one version the bracket supporting the honeycomb is in the form of a pyramid like frame with the honeycomb forming its base, and lies, in its rest position, substantially perpendicular to the platen along the breadth of the trolley. The type propelling means is located within the space within the frame.
~wo palrs of field coils act on magnets mounted on each of the four sides of the frame and control of the deflection of the bracket by the currents ~flowing in the coils is governed by servo-loop:~signals. These are :
provided by optical-encoder grills mounted on the : bracket moving relative to transducers mounted on the trolley, or vice-versa. In one form, the honeycomb has substantially the same number of t~pe-receiving cavities width-wise as it does in depth~ It will be appreciated, by way of example, for~ten pitch type (ten printed characters to an inch), -the maximum :
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1~
g - deflection from its rest position to an extreme print position only requires a three-quarterinch horizontal and vertical movement of a one and one half inch square honeycomb housing one hundred characters.
S In another version of this embodiment of the invention, the bracket supporting the honeycomb moves within a further bracket affixed to the trolley and is guided therein by gimbals or grooves giving freedom in the horizontal and vertical senses relative to the platen of the printer. Deflection of the first bracket and therefore the honeycomb to a desired print position is effected by means of solenoids, or small linear motors, acting on the gimbal and bracket assembly. The honeycomb itself may be constructed from, or is clad by, an electrically conductive material, and the linear motors themselves act directly upon the honeycomb and/or its cladding to move the honeycomb to the desired position. In a preferred form the sides of the honeycomb itself are fashioned from an aluminium alloy.~
; ~n printers of the daisy wheel kind, sophisticated servo-mechanisms are required to arrest accuratèly a daisy wheel in a given print position, there being usually nearly one hundred petals - and~
therefore stop positions - on most daisy wheels.
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In a further feature, also relating to the use of linear induction motors to move the honeycomb, a servo-mechanism utilized for controlling the position of the honeycomb relative to the print hammer is able so to do by means of impulses received -from a combination of toothed notches on the honeycomb and/or its cladding moving relative to fixed electromagnetic sensors, or vice-versa. The notches may correspond directly to the position of rows and columns of types, thus the counting of impulses created by movement of the notches relative to the sensors in the vertical and or horizontal directions establishes the precise position of a given type, relative to the hammer. It will be appreciated that for a ten square honeycomb accommodating one hundred types, only ten stop positions are required respectively in`the hor`izontal and vertical senses.
In a further feature~ the honeycomb is moved relatlve to the p~rint ha~ner by stepping motors.
Energisatlon of the colls of the s~tepping motors in a given sequence attracts pole~pieces~embedded~within the honeycomb,;and thus~ the~honeycomb~ltself,~to stable detent positions, these positlons corresponding to individual rows and;~columns~withln the honeycomb.
No servo-mechanism is required in this arrangement.
Furthennore, in a further scheme in~which no servo-:
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mechanism is required, rotary stepper motors takethe place of the linear stepping motors, and position the honeycomb in the vertical~horizontal senses by means of pinions engaging racks affixed to the honeycomb. Imparting an appropriate number of stepping pulses to each motor locates the selected type opposite the print hammer.
Referring now to the honeycomb itself, in use a type returns towards its original, rest position in its cell - after having been impelled towards the platen of the printer by the propelling means - as a result of bouncing off the resilient platen. In order to assist this return the honeycomb as a whole may be inclined away from the vertical and away from the upper portion of the platen, but in such a way that the face of the honeycomb remains substantially perpendicuIar to a radius of the platen, the arrangement being such that gravltational forces aid the said bouncing effect~restoring type to its original position within ltS cavity.
An important aspect of the inventlon is the interchangeability of typ~s within the honeycomb.
Any chæacter font desired by a~particular user can thereby be provided up to the capacity of the honeycomb. In practice, easy lnterchangeability~
~ is desirablo, but not at the expeuse of types slipping ., . . ~
1~71D2~5 S
from their respective positions during printing operation and during removal of the honeycomb from the printer. A removable retaining member may be provided to retain the types in their cells while permitting movement between their rest and impression positions. Thus grooves on the honeycomb slideably accommodate, on one of its open surfaces, a slotted base plate, the slots of the base plate engaging - -corresponding slots along the body of each type, there being sufficient freedom to permit each type to impinge against the platen when impelled theretowards by the print hammer. Thus, in this arrangement, the slotted base plate prevents types from inadvertently falling from the honeycomb, but, on removal from its supporting grooves, allows the types to be withdrawn and exchanged.
The invention further providQs a word processor~incorporating a printi~ng devlce embodying the second aspect of the present invention.
The invention will now be~described in~more detail, by way of examp1eJ with reference to~the~
accompanying~drawings in which:
Figure 1 is a somewhat schematic perspective view of part of a printing device embodying the present invention;
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Figure 2 is an illustration showing to an enlarged scale the print head of the printer of Figure l;
Figure 3 is a block circuit diagram showing the derivation of control signals used within the printer of Figure 1, -Figure 4 is an illustration showing yet another embodiment of printing device according to the present invention, 10Figure 5 shows part of a printing device embodying the invention and including linear motors acting on a honeycomb printing head, Figure 6 is an illustration showing a honeycomb printing head and position sensor embodying the present invention,:
Figure 7 shows linear stepping motors acting on a honeycomb printing head embodying:the present invention; : : :
Figure 8 shows:part of a~printing:device ~
embodying the invention in~luding a honeycomb printing : head;
Figure 9 shows detached, constituent parts together comprising a honeycomb prlnting:~h:ead~embodying :
the present invention~
Figure 10 shows waveforms~applied to a linear : motor used within a printer a~cording to Figure l;
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Figure 11 shows a phase control network for regulating supplies to the linear motor; and Figure 12 is a cross-sectional view of a print hammer of an embodiment of the present invention.
Referring to Figure 1, a printing device according to the invention is generally designated 10 and includes a platen 11 embraced circumferentially along part of its length by stationery 12. The coil of an alternating current linear induction motor 13 is mounted on the base of the printer, and is used to propel a trolley 14 in a horizontal sense from left to right and vice-versa, as indicated by the arrow. The trolley is held above and guided along the ~ motor by means of tongues, two of which are shown at 15 and 16, engaging grooves 17 running along the :
motor's length. A print mechanism 18 is supported on the trolley 14 and includes a suspended~honeycomb print head 19 and means~(not shown3 for mcving the head relative to an electromagnetic hammer 20, also~ unted 20 ~on the trolley. Information on the~position of the ~trolley and its movement is~obtained from a-transducer 21 mounted thereon and~arranged to scan an optical encoder grill 22 affixed to~-t~e linear motor. ~A 'snake' :
23 attached at one end to the trolley and at the ~ ~ :
25~ other to the base of the printer is used to convey and protect signal cables connected to the transducer and : ~
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Ig ,~ _ other components of the print mechanism.
The print head 19 of the printer is now described with reference to Figure 2 which shows from the rear such a head but to an enlarged scale. The head consists of a symmetrical open-sided honeycomb-like array of a multiplicity of cavities. Each of the cavities is, in this example, of square cross-section and is occupied by a slideable type, two of which are shown protruding, for clarity, from the rear face of the hoenycomb at 24. There is no physical bond between each ty e and the surrounding honeycomb frame, with the exception of a type-retainlng bracket to be hereinafter described in more detail~ mus each type may be directly extracted from the honeyaomb on removal of the said bracket. Each type ends in a prin-t die, as shown for example at 25. In practicé, lips on each type 26~, not shown, prevent protrusion o~ the types from the;plane of the rear face of the~element.
In~one example, the honeycomb~is constructed~from~
lightweight plastics, but has attached to its rear face a ferromagnetic lattice. m e types may be magnetised to aid their retention~in the honeycomb. ~The lattice may be magnetised instead.~ ~
~ ~ The mode of~operation of the pri~nting device of Figures 1 and 2 is as follows:-,, - ~ .
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The linear motor first causes the trolley to move to the first desired print position. Whilst this is happening, the honeycomb is deflected by electromagnetic forces acting on its suspension unit to a position which brings the desired t~pe opposite the electromagnetic hammer 20 (see Figure 1). As soon as the trolley stops, and the honeycomb is positioned, the hammer is fired and the selected type slides along its cavity sufficiently to impinge, through an ink ribbon (not shown) onto the stationery 12 mounted within the printer, thereby leaving an inked impression.
The type reiurns to its cavity as a result of bouncing off the resilient platen, and may also be aided in this respect by the ink ribbon which may be kept appropriately tensioned.
As shown in Figure 12, in a further version each type may contain in its rear end a ferromagnetic core. The hammer itself is magnetised,~and as the hammer and type return from the platen as a result ;~ 20 of bounclng there off, the attractlon exerted by the hammer on the core within the type ensures the type returns to ltS cavity.~ The hamrner by virtue of~its return rnomentum, breaks away from the type, once the protruding Iips~26 prevent~further movement thereof, so becoming ready for the next impact~a (The hammèr also returns, in part, as~a result~of the type bouncing ~ ' ., .
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-~:~7~5 off the platen, the 'bounce' being transmitted to the body of the hammer from the body of the type. A
return spring may aid the return of the manner). The trolley is then moved by the linear motor to the next desired position, the honeycomb is repositioned, and the process repeated~ Thus the desired sequence of characters is printed. The honeycomb may be detached from the suspension unit by the operator using the printer. m e cavities of the honeycomb may then be filled by types corresponding exactly to the operator's particular requirements, so providing a very flexible character repertoire. Furthermore, with regard to wear, only those types in most frequent use need be replaced, rather than changing the entire lS element. (It will be appreciated ~rom the die illustrated at 25 in Figure 2 that the effective print portion may have considerable body, so reducing necessity ~or frequent replacement.) The method of imparting motion to the trolley,~ and its control, will~now be described with :
reference to Figures lO~and 11.
- In one embodiment, a two-phase linear induction motor is employed~ to move~the said trolley.
A phase control network, responsive to trolley positioning commands recei~ed by the printer, regulates ~whether phase a leads b, or b leads a, (see Figures . ..
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- . .
:1~7~2~5 æl ;~
10 i and ii), this thus determines the direction of thrust. In addition to this, the amplitude of thrust exerted by the linear motor on the trolley is similarly detennined, being dependent on the extent to which one phase is made to lead the other. Thus, for a corresponding pole pitch, a maximum thrust is experienced with a ~2 radians out of phase with b, whereas no thrust is experienced with the two phases superimposed (see Figure 10 iii). The phase control network need therefore only regulate the relative phasing of the two supplies a and b, to both control the direction of thrust imparted to the trolley and its amplitude, so providing means conveniently responsive to a servo-loop control system for controlling the position of the trolley.
A convenient form of phase control network may take that shown in Figure 11O In this, regulation of the gating currents to four thyristors 126, 127, 128 .
~ and 129, controls the degree of~direct and phase- :
displaced alternating current supplied to each coll of the motor.: Thus, with 126 and~l29~switched on,~ fu11 : thrust will be experienced in one dlrection:and, conversely, switching on 127 and 128 causes full thrust to be experienced in the opposite direction~ Intermediate :
degrees of thrust in each:direction are obtained by appropriately controlling the flr1ng periods of the . . . ., . - . ~ . .
, ~7~2~5 various thyristors.
To obtain, however, carefully regulated acceleration and deceleration of the trolley, a modified embodiment of the invention makes use of control of both the amplitude of the applied currents and also their phase displacements. An example of such control is now described with reference to Figure 3.
Suppose a displacement D is to be effected, D being represented by a multiple bit binary word indicating the number of gradationst~ be traversed by the transducer 21 over the optical encoder grill 2 (se~ Figure 1). The start position of the trolley Ps is first added in a binary adder to ~, to arrive at the finishing position, Pf~ (Ps is derived from an internal binary counter, Pa~ which permanently follows the output of the transducer). Once Pf lS obtained, ~
the absolute mid-point position Pm is~also calculated;
see equation l~in Figure 3. A digital to analogue coverter, 28,~ then lnterprets these~signals to regulate khe amplitude,;A, of the supplies a and b, according to ~the extent of the dispLaaement to be ~effected. Thus the accelerating thrust, Aa is~made proportional to a combination of the initial difference between Ps and Pm, and thereafter~to the difference ; between the absolute positi~n of the trolley, ' ~ ' :
~7~ S
~3 Pa, and, say, the mid-point position Pm. (Note, for very small displacements, a minimum value of Aa is applied to overcome static friction.) As the mid-point is reached, the accelerating thrust. is substantially reduced. However, as soon as the mid-point is crossed, the decelerating thrust Ad is made sufficient to counter the velocity imparted to the trolley, and is therefore determined partly by the difference between Pm and Pf (reflecting the velocity imparted by Aa), 10 and also, towards the end of the trolley's travel, by -the difference between Pa and Pf. Suitably regulating the degree to which these two quantities act on the deceleration ensures the trolley actually arrives at its destination. Simultaneous to the reyulation of the amplitude of thrust A, Pm and Pa are fed to a comparator, 29, to determine the phase relationship -between a and b~and thus the direction of thrust, so giving rise, effectively, to the two components Aa and Ad. A component of the signal A is~also fed to the comparator to further influence the phase relationship accordlng to the thrust required, as described earlierO The use of absolute reference positions,~such~as Ps and Pa/ enables comparison to be made with predetermined`reference positions, so safeguarding agalnst such eventualities as displacements being effected which would otherwise result in the :
~,~
: ; ~ '.
, -13~7~ZC~S
trolley crashing into end-stops mounted on the printer.
It will be appreciated that the foregoing is given by way of example for one particular embodiment of the invention only. Many methods of servo-control of the movement of the trolley are possible.
In a feature of the invention, once the honeycomb is positioned and the print hammer is fired, energisation of the hammer solenoid causes attraction onto it of the ferromagnetic rear face of the honeycomb, so preventing relative movement therebetween while the firing pin of the hammer propels the chosen type forward.
The natural resilience of the support frame detaches the honeycomb from the hammer solenoid once it is de-energised. It will be appreciated that the most commonly used letters within a given character repertoire may be grouped centrally. Thus, for example, :
all but one of the lower case letters of the English~
alphabet will occupy a five square matrix, so requiring - in the~maln -~only a small deflectlon~of the honeycomb from its rest position while printing.
Referring to Figure 5, two-phase linear induction motors depcited at I10 and lll are shown acting on a honeycomb printing head 19, and a thrust plate 113 respectively. The print~head is free to move in a vertical sense relative to the motor 110.
The linear notor 110 acts directly on the print ., :
:
.
.. . . .
. . . ~ .
1:~7~b2~5 %~
element l9, which itself is constructed from an aluminium alloy, to establish vertical movement thereof.
The thrust plate 113 is affixed to the base of the motor llO, and is acted upon by the motor 111 to cause horizontal displacements of the honeycomb and motor llO
combination. In use, appropriate phasing of currents to the two motors thereby establishes both horizontal and vertical movement of the honeycomb to any desired -position. Third and fourth motors may be provided opposite those shown at lO and ll to increase the thrust exerted upon the honeycomb and thus the speed at which a desired position is reached. The honeycomb may he supported by tongues emerging therefrom and slideably engaging grooves 14 in the linear motor llO.
~eferring to Figure 6 in an alternative arrangement, teeth 115 are shown protruding from a lateral face of the print element l9. A fixed ~ -electromagnetic sensor 116 is positioned adjacent to the teeth~for their detection~ A similar arrangement (not shown) exists on the horizontal ~ace~of the honeycomb,~or~the thrust plate 113. ~The;position of the honeycomb~relative to the linear tor (shown in Figure S) is established by detectlon of the number of teeth passing either sensor7 The teeth may each :
correspond to each row~and or column of types housed within the honeycomb, the axxangement being such that .
- - ~ ,.. ....... ......... . ..
::
" , . .:
1~71~Z~3S
2~
.`L~
a servo-mechanism circuit controlling the action of the linear motors ensures the required displacement of the honeycomb to a desired position by counting the number of teeth passing each sensor. Alternating currents are passed through the coils of the sensors, and the horizontal/vertical teeth of the honeycomb are detected by virtue of the change they effect in the inductance of the sensor/tooth combination, and thus the current passing through the respective sensor coil(s).
An alternative method of effecting movement of the honeycomb is now described with reference to Figure 7. Instead of using linear induction motors, linear stepping motors are employed~ These are shown, . .
schematically, at 117 and 118. Magnetised cores 119 and 120 are embedded in the sides of the honeycomb.
The sequence of North/South pole magnetisation of the cores is such that suitable energisation .
sequences of the coils of the stepping motors causes horizontal and vertical move~ent of the :
honeycomb to a desired position. One or other of the~
motors 117, 118 of course moves with the honeycomb during actuation of the~other motor 118 or 117.
In this arrangement, st~ble detent positions of the cores opposite;the poles of the stepping motors correspond to individual rows and columns~of types ~: ' ~ ' :
, ~3L71D2~5 t~
within the honeycomb, thus no servo-mechanism is required.
As described above, the types, having first been impelled forwards, return to their cavities within the honeycomb as a result of bouncing off a resilient platen of the printer. In a further feature, the honeycomb itself, see reference 19 of Figure 8, is inclined to the vertical. The inclination is such that the rear face of the honeycomb forms an acute angle with the trolley 14 of the printer on which the honeycomb/motor assemblies are mounted. The honeycomb remalns however substantially tangential to the platenO
In this arrangement, types are impelled lS forwards, as also described earlier, by an electromagnetically propelled hammer 122. (~he hammer is a1so inclined relative to the trolley, being at ~r1ght angles to the rear face of the honeycomb.) The effect of the inclination~of the honeycomb;, is ~o ~
enhance the~restitution of types into ~heir~cavi~ies, by virtue~of~ihe gravitational component acting thereon.
~ v During printing operations, or during the exchange of honeycombs,~it~is~important to prevent types from escaping from their cavlties.~
However, an lmportant aspect of~the invention is the .
interchangeability of types~ To fulfil these .,~ :
::
; ' ~ , .
D2~5 2 ~
requirements, grooves 123 on the honeycomb, 23, see Figure 9, slideably accommodate, on one of its open surfaces, a slotted base plate 124. The slots of the base plate engage corresponding slots 125 along the body of each type. The longitudinal length of the slots 25 provides sufficient freedom to permit each type to impinge against the platen, and to bounce back, but by virtue of their engagement with the base plate, prevents types from falling out, or bouncing back too far~ If it is required to exchange types, the base plate may be withdrawn from its grooves, so freeing them for this purpose.
In yet a further embodiment of the invention, for applications where high speed print is required, movement of the honeycomb and its print types is effected in the vertical sense only, see Figure 4~
In this example, a small stepper motor 51 15 used by means of a crank arrangement 52, to raise and lower the honeycomb OD guide rods~53 and 54 affixed to the ;
base of the trolley 30. A circular optical encoder grill 55 is mounted on the axls of the motor and serves, in conjuction with a transducer 56, to provide information on the position of;the honeycomb.
Mounted above the motor and directly in front of the honeycomb is a battery of electromagnetic hammers ~
(shown offset for clarity at 57), one for each column ` ":
: ~ :
.
. . ~
~7~2~)5 "2q - ~6 of cavities in the honeycomb. (In an alternative arrangement, the honeycomb is raised and lowered by a servo-controlled linear motor, or by a stepper motor.) In this arrangement, when a sequence of characters is to be printed, control circuitry regulates the movement of the trolley such as to bring the column containing the desired type to the desired print position. At the same time, the stepper tor raises or lowers the honeycomb to the correct height and the appropriate hammer is then fired. It will be appreciated that for a honeycomb twelve cavities wide, the motor need only oscillate between two adjacent positions to present nearly all the lower case characters of this alphabet to the battery. Furthermore, by comparing the character~string to be printed with the corresponding lateral position of the honeycomb, it will frequently be possible to fire more than one han~ner at a tlme, so improving the rate of print. When this occurs, to avoid 'back-stepping', the chaxacters~
may be printed not necessarily one after the other~ ;
For example, the honeycomb may be so positioned that a letter or letters of a second word may be printed whiIe a first word is being formed, and so on. The extent to which this occurs is of course determined by any given character sequence, and may be optimised by comparison registers within the printer controlling "
~P7~ 5 ~ 6 f~
. . .
the motion of the trolley and honeycomb relative to the stationery~ The positioning of the hammers and honeycomb relative to the trolley may be adapted to be at right angles to the arrangement shown in Figure 4 for oriental printing requirements.
It will be appreciated that the various modifications described above to -the basic form of the printing device of Figure 1 may be used alone or in various appropriate combinations with one another.
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.
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Claims (43)
1. A printing head comprising: means defining an array of cells; a plurality of individually replaceable types for printing respective characters, each of the types being individually interchangeably mounted in, guided by, and freely slidable relative to respective ones of the cells from an extended impression position towards a retracted rest position, the types during printing being free of mechanical connection with the array defining means other than their slidable mounting in the cells thereof, the printing head being mountable in a printing device so that each of the types is movable between its rest position and its impression position by a component of the printing device, the arrangement of the cells and types in the printing device being such that each type is returnable towards its rest position from its impression position by resiliently rebounding from a platen.
2. A head according to claim 1 wherein the array comprises rows and columns of the cells.
3. A head according to claim 1 or 2 wherein the cells and types are of corresponding rectangular cross-section.
4. A head according to claim 1 and comprising means to magnetically retain each type in its rest position.
5. A head according to claim 1 further comprising a removable retaining member to retain the types within their cells while allowing movement thereof between their rest and impression positions.
6. A printing device comprising: a platen for supporting items on which text is to be printed, the platen having an axis; a printing head for printing text, the printing head comprising means defining an array of cells having axes which are at least approximately horizontal and a plurality of individually replaceable types for printing respective characters, the types being interchangeably mounted in, guided by, and freely slidable in respective ones the cells from an extended impression position towards a retracted rest position, the types being free of mechanical connection with the array defining means other than their slidably mounting in the cells thereof; a support carrying the printing head and movable longitudinally relative to the platen between a number of print poritions,the relationship between the support and the printing head being such that for each type, on its impact with the platen, the force tending to restore it from its impression position towards its rest position derives substantially solely from its resiliently impacting with the platen, the support constraining the printing head so as to be movable only in a plane parallel to the axis of the platen; means for propelling the types to their impression positions; and drive means for causing said relative movement of the platen and support.
7. A printing device according to claim 6 wherein said support is a trolley and further comprising a guide rail arrangement along which the trolley is movably mounted.
8. A printing device according to claim 6 wherein the drive means comprises a linear stepping motor.
9. A printing device according to claim 8 wherein said motor comprises an armature and the support comprises said stator of said motor.
10. A printing device according to claim 6 wherein means are provided defining a plurality of detent positions on the support relative to the platen.
11. A printing device according to claim 6, further comprising a transducer arrangement for effecting closed loop control of the drive means.
12. A printing device according to claim 6 wherein the printing head is movable relative to the support in at least one direction.
13. A printing device according to claim 12 wherein the propelling means comprises a print hammer and the printing head is movable relative to said support in the horizontal and vertical directions to present a selected type to the print hammer.
14. A printing device according to claim 12 wherein the printing head is movable in the one direction relative to the support and the prope11ing means comprises a plurality of print hammer each associated with a group of said cells which are aligned in said one direction.
15. A printing device according to claim 13 wherein the ce11s are each open to their rears and the print hammer or hammers move in the longitudinal directions of the cells when propelling a selected type towards the platen.
16. A printing device according to claim 12 further comprising at least one linear stepping motor by means of which the printing head is movable in the at least one direction.
17. A printing device according to claim 12 and comprising a transducer arrangement for effecting closed loop control of the position of the printing head relative to the support.
18. A printing device according to claim 6 wherein the array comprises row and columns of cells.
19. A printing device according to claim 7 wherein the cells and types are of corresponding rectangular cross-section.
20. A printing device according to claim 6 further comprising a removable retaining member to retain the types within their cells while allowing movement thereof between their rest and impression positions.
21. A printing device according to claim 12 wherein the printing head is movable relative to the support in the vertical direction and further comprising a linear motor to effect vertical movement of the printing head, the linear motor acting directly on the printing head.
22. A printing device according to claim 6 wherein there is magnetic attraction between the hammer and types.
23. A printing head comprising: means defining an array of cells; a plurality of individually replaceable types for printing respective characters, each of the types being individually interchangeably mounted in, guided by and freely slidable relative to respective ones of the cells from an extended impression position towards a retracted rest position,the printing head being mountable in a printing device so that each of the types is movable between its rest position and its impression position by a component of the printing device, the arrangement of the cells and types in the printing device being such that each type is returnable towards its rest position from its impression position by resiliently rebounding from a platen.
24. A head according to claim 23 wherein the array comprises rows and columns of the cells.
25. A head according to claim 23 or 24 wherein the cells and types are of corresponding rectangular cross-section.
26. A head according to claim 23 and comprising means to magnetically retain each type in its rest position.
27. A head according to claim 24 further comprising a removable retaining member to retain the types within their cells while allowing movement thereof between their rest and impression positions.
28. A printing device comprising a platen for supporting items on which text is to be printed, the platen having an axis a printing head for printing text, the printing head comprising means defining an array of cells hav ing axes which are at least approximately horizontal and a plarality of individually replaceable types for printlng respectlve characters, the types being interchangeably mounted in, guided by, and freely slideably mounted in respective ones of the cells from an extended impression position towards a retracted rest position; a support carrying the printing head and movable longitudinally relative to the platen between a number of print positions, the relationship between the support and the printing head being such that for each type, on its impact with the platen, the force tending to restore it from its impression position towards its rest position derives predominantly from its resiliently impacting with the platen, means for propelling the types to their impression positions; and drive means for causing said relative movement of the platen and support.
29. A printing device according to claim 28 wherein said support is a trolley and further comprising a guide rail arrangement along which the trolley is movably mounted.
30. A printing device according to claim 29 wherein the drive means comprises a linear stepping motor.
31. A printing device according to claim 30 wherein said motor comprises an armature and the support comprises said stator of said motor.
32. A printing device according to claim 28 wherein means are provided defining a plurality of detent positions on the support relative to the platen.
33. R printing device according to claim 28, further comprising a transducer arrangement for effecting closed loop control of the drive means.
34. A printing device according to claim 28 wherein the printing head is movable relative to the support in at least one direction.
35. A printing device according to claim 34 wherein the propelling means comprises a print hammer and the printing head is movable relative to said support in the horizontal and vertical directions to present a selected type to the print hammer.
36. A printing device according to claim 34 wherein the printing head is movable in the one direction relative to the support and the propelling means comprises a plurality of print hammers each associated with a group of said ce11s which are aligned in said one direction.
37. A printing device according to claim 35 wherein the cells are each open to their rears and the print hammer or hammers move in the longitudinal directions of the cells when propelling a selected type towards the platen.
38. A printing device according to claim 34 further comprising at least one linear stepping motor by means of which the printing head is movable in the at least one direction.
39. A printing device according to claim 34 and comprising a transducer arrangement for effecting closed loop control of the position of the printing head relative to the support.
40. A printing device according to claim 28 wherein the array comprises row and columns of cells.
41. A printing device according to claim 28 wherein the cells and types are of corresponding rectangular cross-section.
42. A printing device according to claim 28 further comprising a removable retaining member to retain the types within their cells while allowing movement thereof between their rest and impression positions.
43. A printing device according to claim 34 wherein the printing head is movable relative to the support in the vertical direction and further comprising a linear motor to effect vertical movement of the printing head, the linear motor acting directly on the printing head.
Applications Claiming Priority (4)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB7917467 | 1979-05-18 | ||
| GB7917467 | 1979-05-18 | ||
| GB8001876 | 1980-01-21 | ||
| GB8001876 | 1980-01-21 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1170205A true CA1170205A (en) | 1984-07-03 |
Family
ID=26271580
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000352094A Expired CA1170205A (en) | 1979-05-18 | 1980-05-16 | Printing head and printing device |
Country Status (5)
| Country | Link |
|---|---|
| EP (1) | EP0019453B1 (en) |
| AU (1) | AU541660B2 (en) |
| CA (1) | CA1170205A (en) |
| DE (1) | DE3066932D1 (en) |
| DK (1) | DK216580A (en) |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE3515108C1 (en) * | 1985-04-26 | 1986-08-28 | TA Triumph-Adler AG, 8500 Nürnberg | Method for setting the print hammer of typewriters or similar devices with a type matrix that can be set in the X-Y direction |
| DE10106897A1 (en) * | 2001-02-10 | 2002-08-14 | Steinhauer Elmasch Gmbh | Labeling device has temperature controled print dies on type carrier movable linearly in at least one directional component by motor drive controled preferably via electronic interface |
| DE102010018734B3 (en) * | 2010-04-29 | 2011-07-28 | Mühlbauer AG, 93426 | Method and device for printing value or security documents |
Family Cites Families (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3007400A (en) * | 1958-12-04 | 1961-11-07 | Ibm | Printing apparatus and method for assembly |
| DE1197474B (en) * | 1960-01-07 | 1965-07-29 | Herman Emil Krutschau | Key-operated, electromagnetically driven printing mechanism of a writing device |
| NL7107133A (en) * | 1970-05-28 | 1971-11-30 | ||
| US4015699A (en) * | 1974-04-08 | 1977-04-05 | Burroughs Corporation | Alphanumeric serial printer with a flexible membrane printing element |
| US4064983A (en) * | 1976-08-02 | 1977-12-27 | Hitachi, Ltd. | Japanese character word processing system |
-
1980
- 1980-05-13 DE DE8080301569T patent/DE3066932D1/en not_active Expired
- 1980-05-13 EP EP19800301569 patent/EP0019453B1/en not_active Expired
- 1980-05-16 AU AU58459/80A patent/AU541660B2/en not_active Expired - Fee Related
- 1980-05-16 DK DK216580A patent/DK216580A/en unknown
- 1980-05-16 CA CA000352094A patent/CA1170205A/en not_active Expired
Also Published As
| Publication number | Publication date |
|---|---|
| DE3066932D1 (en) | 1984-04-19 |
| EP0019453B1 (en) | 1984-03-14 |
| AU5845980A (en) | 1980-11-20 |
| DK216580A (en) | 1980-11-19 |
| EP0019453A1 (en) | 1980-11-26 |
| AU541660B2 (en) | 1985-01-17 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKEX | Expiry |