CA1089921A - Printer with moving printing head - Google Patents
Printer with moving printing headInfo
- Publication number
- CA1089921A CA1089921A CA289,357A CA289357A CA1089921A CA 1089921 A CA1089921 A CA 1089921A CA 289357 A CA289357 A CA 289357A CA 1089921 A CA1089921 A CA 1089921A
- Authority
- CA
- Canada
- Prior art keywords
- thermal printer
- printing
- stepping
- carriage
- 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
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
- H04N1/00—Scanning, transmission or reproduction of documents or the like, e.g. facsimile transmission; Details thereof
- H04N1/40—Picture signal circuits
- H04N1/40025—Circuits exciting or modulating particular heads for reproducing continuous tone value scales
- H04N1/40031—Circuits exciting or modulating particular heads for reproducing continuous tone value scales for a plurality of reproducing elements simultaneously
-
- 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
- B41J19/00—Character- or line-spacing mechanisms
- B41J19/18—Character-spacing or back-spacing mechanisms; Carriage return or release devices therefor
- B41J19/20—Positive-feed character-spacing mechanisms
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
- H04N1/00—Scanning, transmission or reproduction of documents or the like, e.g. facsimile transmission; Details thereof
- H04N1/024—Details of scanning heads ; Means for illuminating the original
- H04N1/032—Details of scanning heads ; Means for illuminating the original for picture information reproduction
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
- H04N1/00—Scanning, transmission or reproduction of documents or the like, e.g. facsimile transmission; Details thereof
- H04N1/04—Scanning arrangements, i.e. arrangements for the displacement of active reading or reproducing elements relative to the original or reproducing medium, or vice versa
- H04N1/19—Scanning arrangements, i.e. arrangements for the displacement of active reading or reproducing elements relative to the original or reproducing medium, or vice versa using multi-element arrays
- H04N1/191—Scanning arrangements, i.e. arrangements for the displacement of active reading or reproducing elements relative to the original or reproducing medium, or vice versa using multi-element arrays the array comprising a one-dimensional array, or a combination of one-dimensional arrays, or a substantially one-dimensional array, e.g. an array of staggered elements
- H04N1/192—Simultaneously or substantially simultaneously scanning picture elements on one main scanning line
Landscapes
- Engineering & Computer Science (AREA)
- Multimedia (AREA)
- Signal Processing (AREA)
- Particle Formation And Scattering Control In Inkjet Printers (AREA)
Abstract
Abstract of the Disclosure A printer has a moving printing head provided with a number of equally spaced printing positions. The printing positions are spaced apart a predetermined number of print elements and signals are fed to the printing positions for printing, as determined. Between each signal application the printing head is stepped one print element, depending upon the number of printing positions so the total movement of the printing head is only a fraction of the width of the paper being printed. The printing head can be stepped first one way and then the other. The printing positions can be thermal printing members.
Description
~L~ 9 9 ~L
This invention relates to a printer having a moving printing head and iS particularly, though not exclusively, applicable to facsimile printers.
Various ways of printing are used in facsimile and other types o~ printers. Typical examples are ink jet in which a Jet of ink is separated into separate drops, which are then deflected to impinge on a paper sheet, and thermal in which dots are formed by heating of a thermally responsiv~ paper. There are various disadvantages with such methods. In ink jet, ink mist is formed, ink not împinging on the shect 0 must be collected and preferably recirculated, with filtering requirements and problems through loss of solvent. Also there is a physical restriction ~ -on the spacing of ejector heads. In thermal printing, for high resolution, problems arise in producing hot spots close together and the conductor pattern to the hot spots is often complex, with narrow conductors closely spaced, creating manufactur;ng diff;cult;es and loss of rel;ability.
The present invention provides a printing head having ; -a relatively smaller number of printing positions spaced apart at equal distances, the printing head being stepped laterally in a predetermined sequence for a l;ne. Conveniently the head steps laterally in one direction when printing a first line of dots and steps laterally in the other direction for the next line of dots, and so on. The printing can be thermal 3 ink jet, or other.
The in~ention will be understood by the following descript;on oF certain embodiments, by way of example, in conjunction with the accompànying drawings, in which: ~
Figure 1 is a diagrammat;c plan v;ew of a printing head -using resistors to praduce hot spots for thermal printing;
Figure 2 is a cross-section on the line II-II of Figure 1, to an enlarged scalej and ~ ;
Flgure 3 is a diagrammatic illustration of a printing head as in Figures 1 and 2 and an associated control system.
-- 1 -- . . , ~ ",' ..
.
~. .
Considering Figures 1 and 2, an elec~rically insulating substrate 10 is slidably mounted on a support member 11 for reciprocal movement as indicated by double-ended arrow A. Extending along the substrate is a plural;ty of resistors 12. Resistors 12 are connected to a common voltage source through a bus-bar 13 and connections 14 extending from the bus-bar to one side of each resistor. A contact pad 15 is provided at one end of the bus-bar.
Each resistor 12 is individually connected by conductors 16 to contact pads 17 at the end of the substrate. Each resistor is thus commonly connected at one side and individually connected at the other side.
Assum~ng a required print density of 200 lines per inch vertically and horizontally on an eight inch wide page, that is 1600 print elements, a printing head as ;n Figures 1 and 2 would have X resistors of approximately 7 x 7 mils spaced gO00/X mils apart. Assuming forty resistors 12 located 200 mils apart (40 print elements), the printing head of Figures 1 and 2 would have one common electrode - bus-bar 13 and forty individual conductors 16.
The printing head would print as follows, relatiny the description to Figure 3:
(a) a complete line of data (1~00 bits) is loaded into memory 20, (b) starting with bit 1 every 40th bit is loaded into the shift register 21;
(c) these forty points are printed by powering the drive electronics 22 to the bar 13 (resistors 12) and a dot will be printed at each point as required by the data input, (d~ the bar (resistors 12) is displaced laterally by 5 mils via for example, (one print element) a stepping motor 23 displacing the print head 24;
. : ~ ;, . ~ . - -z~
(e) starting with bit member 2, every 40th bit is loaded into the shift register 21, (f) these forty points printed as in step (c);
(9~ bar 13 moved laterally by ~ mils.
Steps (a) to ~d) are repeated until the entire line of 1600 bits is printed (forty cycles). The paper then is advanced 5 mils ;n a direct;on normal to the lateral extension of the print bar and a new line of data is loaded into the memory. The printing head then prints this line, conveniently in reverse, but if desired the printing head can be returned to the original position ~e~ore printing the second line. However, with the speed of printing available, unproductive movement of the printing head is to be avoided, if possible. The overall operation is controlled by a timing and control unit 25.
The memory 20, shift register 21, drive electronics 22 ;~
and timing and control un;t 25 are of conventional form. -The lateral displacement of the printing head 24 can be by various means. Thus, as given as an example, a stepping motor may be used. The stepping motor can drive a cam which in turn moves the printing head. A typical speed of printing is approximately 1500 lines per minute (without white skipping - that is without moving in one step of the paper to cover the white gap between adjacent lines of print).
If the print bar had eighty resistors then the bar would only have to ;~
move 100 mils and the speed would double. White skipping will increase the speed. These figures are based on stepping the printing head, and the print bar, laterally at 1000 steps per second. Stepping motors are capable o~ higher stepping speeds than this and thus the printing speed can be increased.
The present invention provides several advantages over previous thermal printers. The printing head, composed of print bars ~
30 and associated conductors, is simpler to make. It is easier to tailor -spot size, overlap can be provided if desired, or at least contiguity of spots. Uniformi~y o~ resistance of the print bar is not critical, as a result of individual access. By individual access is meant that each spot is addressed on each side by its own unique pair of conductors, even though on one side these conductors are eventually connected to a common bus-bar 13, in Flgure 1, each conductor 16 is individually controllable to provide equal heating of each resistor 12 independent of the actual resistor value. This is not possible in matrix connection systems as the same drive current is applied to every resistor ~or resistor segment).
The drive electroni`cs 22 can be simpler and of lower perFormance as a result of the individual addressing instead of a matr;x ~ -connection arrangement. No diodes are required in the connections to resistors to avoid leakage or cross-flow currents. The number of conductors iSl Of course, considerably reduced, there being only forty-one where forty resistors are provided, compared to 1600 or 1700 elements for a 200 lines per inch matrix for printing without "stepping". This reduces -considerably the complexity in forming conductor patterns and allows wider conductors - with the associated case oF manuFacture, improved reliability and low conductor resistance.
While the invention as described has been considered in relation to a thermal printing head with a multiplicity of resistors to -form "hot spots", it is possible to apply the present invention to other types oF printing, for example ink jet and electrostatic. In an ink jet system, a nozzle would be provided at each position as occupied by a resistor 12 in Figure 1, The associated electrode for each nozzle could be addressed in a similar manner as the resistors 12 are addressed and thus, with Forty nozzles or jets, ink dots can be printed, as desired by the data input - then the printing head stepped, the ink jets actuated, printing head stepped and so on For a complete line. In a conventional single nozzle arrangement either the nozzle or paper has to be stepped For the full width of the paper sheet. In the present invention the head is only stepped one-Fortieth of the sheet Width (-for forty nozzles and sixteen hundred bits per line). Thus a considerable increase in printing speed can be obtained. Simiarly, where ink is ejected electrosta~ically, an electrode would be provided at each position as occup~ed by a resistor 12, with addressing in a similar manner as the resistors 12. Ink dots would be printed as des;red by the data input and then the head stepped, w;th ~urther actuation sequentially, for a complete line.
S
This invention relates to a printer having a moving printing head and iS particularly, though not exclusively, applicable to facsimile printers.
Various ways of printing are used in facsimile and other types o~ printers. Typical examples are ink jet in which a Jet of ink is separated into separate drops, which are then deflected to impinge on a paper sheet, and thermal in which dots are formed by heating of a thermally responsiv~ paper. There are various disadvantages with such methods. In ink jet, ink mist is formed, ink not împinging on the shect 0 must be collected and preferably recirculated, with filtering requirements and problems through loss of solvent. Also there is a physical restriction ~ -on the spacing of ejector heads. In thermal printing, for high resolution, problems arise in producing hot spots close together and the conductor pattern to the hot spots is often complex, with narrow conductors closely spaced, creating manufactur;ng diff;cult;es and loss of rel;ability.
The present invention provides a printing head having ; -a relatively smaller number of printing positions spaced apart at equal distances, the printing head being stepped laterally in a predetermined sequence for a l;ne. Conveniently the head steps laterally in one direction when printing a first line of dots and steps laterally in the other direction for the next line of dots, and so on. The printing can be thermal 3 ink jet, or other.
The in~ention will be understood by the following descript;on oF certain embodiments, by way of example, in conjunction with the accompànying drawings, in which: ~
Figure 1 is a diagrammat;c plan v;ew of a printing head -using resistors to praduce hot spots for thermal printing;
Figure 2 is a cross-section on the line II-II of Figure 1, to an enlarged scalej and ~ ;
Flgure 3 is a diagrammatic illustration of a printing head as in Figures 1 and 2 and an associated control system.
-- 1 -- . . , ~ ",' ..
.
~. .
Considering Figures 1 and 2, an elec~rically insulating substrate 10 is slidably mounted on a support member 11 for reciprocal movement as indicated by double-ended arrow A. Extending along the substrate is a plural;ty of resistors 12. Resistors 12 are connected to a common voltage source through a bus-bar 13 and connections 14 extending from the bus-bar to one side of each resistor. A contact pad 15 is provided at one end of the bus-bar.
Each resistor 12 is individually connected by conductors 16 to contact pads 17 at the end of the substrate. Each resistor is thus commonly connected at one side and individually connected at the other side.
Assum~ng a required print density of 200 lines per inch vertically and horizontally on an eight inch wide page, that is 1600 print elements, a printing head as ;n Figures 1 and 2 would have X resistors of approximately 7 x 7 mils spaced gO00/X mils apart. Assuming forty resistors 12 located 200 mils apart (40 print elements), the printing head of Figures 1 and 2 would have one common electrode - bus-bar 13 and forty individual conductors 16.
The printing head would print as follows, relatiny the description to Figure 3:
(a) a complete line of data (1~00 bits) is loaded into memory 20, (b) starting with bit 1 every 40th bit is loaded into the shift register 21;
(c) these forty points are printed by powering the drive electronics 22 to the bar 13 (resistors 12) and a dot will be printed at each point as required by the data input, (d~ the bar (resistors 12) is displaced laterally by 5 mils via for example, (one print element) a stepping motor 23 displacing the print head 24;
. : ~ ;, . ~ . - -z~
(e) starting with bit member 2, every 40th bit is loaded into the shift register 21, (f) these forty points printed as in step (c);
(9~ bar 13 moved laterally by ~ mils.
Steps (a) to ~d) are repeated until the entire line of 1600 bits is printed (forty cycles). The paper then is advanced 5 mils ;n a direct;on normal to the lateral extension of the print bar and a new line of data is loaded into the memory. The printing head then prints this line, conveniently in reverse, but if desired the printing head can be returned to the original position ~e~ore printing the second line. However, with the speed of printing available, unproductive movement of the printing head is to be avoided, if possible. The overall operation is controlled by a timing and control unit 25.
The memory 20, shift register 21, drive electronics 22 ;~
and timing and control un;t 25 are of conventional form. -The lateral displacement of the printing head 24 can be by various means. Thus, as given as an example, a stepping motor may be used. The stepping motor can drive a cam which in turn moves the printing head. A typical speed of printing is approximately 1500 lines per minute (without white skipping - that is without moving in one step of the paper to cover the white gap between adjacent lines of print).
If the print bar had eighty resistors then the bar would only have to ;~
move 100 mils and the speed would double. White skipping will increase the speed. These figures are based on stepping the printing head, and the print bar, laterally at 1000 steps per second. Stepping motors are capable o~ higher stepping speeds than this and thus the printing speed can be increased.
The present invention provides several advantages over previous thermal printers. The printing head, composed of print bars ~
30 and associated conductors, is simpler to make. It is easier to tailor -spot size, overlap can be provided if desired, or at least contiguity of spots. Uniformi~y o~ resistance of the print bar is not critical, as a result of individual access. By individual access is meant that each spot is addressed on each side by its own unique pair of conductors, even though on one side these conductors are eventually connected to a common bus-bar 13, in Flgure 1, each conductor 16 is individually controllable to provide equal heating of each resistor 12 independent of the actual resistor value. This is not possible in matrix connection systems as the same drive current is applied to every resistor ~or resistor segment).
The drive electroni`cs 22 can be simpler and of lower perFormance as a result of the individual addressing instead of a matr;x ~ -connection arrangement. No diodes are required in the connections to resistors to avoid leakage or cross-flow currents. The number of conductors iSl Of course, considerably reduced, there being only forty-one where forty resistors are provided, compared to 1600 or 1700 elements for a 200 lines per inch matrix for printing without "stepping". This reduces -considerably the complexity in forming conductor patterns and allows wider conductors - with the associated case oF manuFacture, improved reliability and low conductor resistance.
While the invention as described has been considered in relation to a thermal printing head with a multiplicity of resistors to -form "hot spots", it is possible to apply the present invention to other types oF printing, for example ink jet and electrostatic. In an ink jet system, a nozzle would be provided at each position as occupied by a resistor 12 in Figure 1, The associated electrode for each nozzle could be addressed in a similar manner as the resistors 12 are addressed and thus, with Forty nozzles or jets, ink dots can be printed, as desired by the data input - then the printing head stepped, the ink jets actuated, printing head stepped and so on For a complete line. In a conventional single nozzle arrangement either the nozzle or paper has to be stepped For the full width of the paper sheet. In the present invention the head is only stepped one-Fortieth of the sheet Width (-for forty nozzles and sixteen hundred bits per line). Thus a considerable increase in printing speed can be obtained. Simiarly, where ink is ejected electrosta~ically, an electrode would be provided at each position as occup~ed by a resistor 12, with addressing in a similar manner as the resistors 12. Ink dots would be printed as des;red by the data input and then the head stepped, w;th ~urther actuation sequentially, for a complete line.
S
Claims (7)
EXCLUSIVE PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:-
1. A thermal printer comprising a print head including a series of individually addressable spaced print resistors and conductive means for selectively applying print current pulses to produce Joule effect heating thereof, said print head mounted on a carriage;
a carriage stepping means for driving the carriage stepwise in a first direction;
means for mounting thermally sensitive paper adjacent the print head;
paper stepping means for driving the paper stepwise in a second direction perpendicular to the first direction; and means for temporally relating application of said current pulses and stepwise drive of the carriage.
a carriage stepping means for driving the carriage stepwise in a first direction;
means for mounting thermally sensitive paper adjacent the print head;
paper stepping means for driving the paper stepwise in a second direction perpendicular to the first direction; and means for temporally relating application of said current pulses and stepwise drive of the carriage.
2. A thermal printer as claimed in claim 1, each resistor approximately 7X7 mils.
3. A thermal printer as claimed in claim 1, each stepwise movement of the carriage stepping means being approximately 5 mils.
4. A thermal printer as claimed in claim 1, each stepwise movement of the paper stepping means being approximately 5 mils.
5. A thermal printer as claimed in claim 1, further comprising a memory for storing input signals, a shift register for receiving data from the memory, and a drive circuit connected between the shift register and the print head.
6. A thermal printer as claimed in claim 5, each stepping means comprising a stepping motor.
7. A thermal printer as claimed in claim 6, further comprising timing and control means interconnecting stepping motors, the drive circuit, and the memory, whereby the stepping motor is actuated between signals from the drive circuit to the print resistors.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA289,357A CA1089921A (en) | 1977-10-24 | 1977-10-24 | Printer with moving printing head |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA289,357A CA1089921A (en) | 1977-10-24 | 1977-10-24 | Printer with moving printing head |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1089921A true CA1089921A (en) | 1980-11-18 |
Family
ID=4109840
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA289,357A Expired CA1089921A (en) | 1977-10-24 | 1977-10-24 | Printer with moving printing head |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1089921A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0079209A2 (en) * | 1981-11-06 | 1983-05-18 | Fuji Xerox Co., Ltd. | Method of driving a thermal head |
-
1977
- 1977-10-24 CA CA289,357A patent/CA1089921A/en not_active Expired
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0079209A2 (en) * | 1981-11-06 | 1983-05-18 | Fuji Xerox Co., Ltd. | Method of driving a thermal head |
| EP0079209A3 (en) * | 1981-11-06 | 1984-08-29 | Fuji Xerox Co., Ltd. | Method of driving a thermal head |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKEX | Expiry |