US3769631A - Increasing throughput in ink jet printing by drop skipping and reducing ink jet merging and splatter using a stairstep generator - Google Patents

Increasing throughput in ink jet printing by drop skipping and reducing ink jet merging and splatter using a stairstep generator Download PDF

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Publication number
US3769631A
US3769631A US00297546A US3769631DA US3769631A US 3769631 A US3769631 A US 3769631A US 00297546 A US00297546 A US 00297546A US 3769631D A US3769631D A US 3769631DA US 3769631 A US3769631 A US 3769631A
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Prior art keywords
drops
drop
printing
information
ink jet
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US00297546A
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English (en)
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D West
T Williams
J Hill
H Naylor
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International Business Machines Corp
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International Business Machines Corp
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
    • B41J—TYPEWRITERS; SELECTIVE PRINTING MECHANISMS, i.e. MECHANISMS PRINTING OTHERWISE THAN FROM A FORME; CORRECTION OF TYPOGRAPHICAL ERRORS
    • B41J2/00—Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed
    • B41J2/005—Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed characterised by bringing liquid or particles selectively into contact with a printing material
    • B41J2/01—Ink jet
    • B41J2/07—Ink jet characterised by jet control
    • B41J2/075—Ink jet characterised by jet control for many-valued deflection
    • B41J2/08—Ink jet characterised by jet control for many-valued deflection charge-control type

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  • FIG. 80 FIG. 8b FIRST CYCLE 0F SECOND CYCLE 0F STAIR STEP GENERATOR, STAIR STEP GENERATOR- 0 DROPS 1 THRU20 DROPS 21THRU40 v VFAMPLIFIER 0 OUTPUT VOLTAGE 24 ⁇ V v- OUTPUT our 2 VOLTAGE l INCREASING TI-IROUGI-IPUT IN INK JET PRINTING BY DROP SKIPPING AND REDUCING INK JET MERGING AND SPLATTER USING A STAIRSTEP GENERATOR PATENT APPLICATION OF INTEREST US. Pat. application Ser. No. 266,790 filed June 27, 1972, entitled Ink Jet Synchronization and Failure Detection System," and having James D. Hill, et a]., as inventors.
  • drops are produced during each of the drop time intervals represented by the coordinate locations of the matrix.
  • the Hill, et al., application referred to above also produces drops for each coordinate location.
  • all drops not required for actual printing on the record medium are directed to a gutter and drops required are directed to the record medium.
  • drops are produced in each 'drop time interval regardless of whether they are needed or not and a great amount of time is wasted in proportion to the amount of time required for printing of information.
  • a charge electrode driver is controlled to produce varying amounts of charges on drops passing therethrough on the way from the. ink jet nozzle to a record medium.
  • the driver is driven by a digital to analog conanalog converter also receives an output from a shift register having a binary zero or one representative of a drop not to be charged or a drop to be charged, respectively.
  • the system provides two control pulses to drive the shift register and counter in one mode, referred to as a normal drop formation and charging mode at a relatively lower speed, such as kiloI-Iertz and further provides pulses at a much higher rate such as 800 kiloI-Iertz in a second or skip mode of operation to step the counter and shift register through unused drop positions when no information (that needs to be printed) is present.
  • a relatively lower speed such as kiloI-Iertz
  • 800 kiloI-Iertz in a second or skip mode of operation to step the counter and shift register through unused drop positions when no information (that needs to be printed) is present.
  • the digital to analog convertor provides a zero level output to the charge electrode driver to insure that any drops that are formed during this interval proceed to the gutter.
  • skipping takes place at a high rate of speed.
  • the digital to analog convertor and counter are replaced by a stairstep generator that provides incremental stepped potentials to the charge electrode driver and that steps normally for normal printing and at high speeds for skipping in a manner similar to the operation just described.
  • the stairstep generator or digital to analog convertor is utilized to produce non-sequential drop placement with appropriate charging as the drops proceed toward the record medium to establish proper deflection in each vertical column of the character box.
  • No drop skipping or high speed skip logic is involved in this technique but it does offer an advantage in reducing the merging of one drop with another as they travel through the air toward the record medium or a splatter effect resulting when one drop impacts on the record medium and partially overlaps a preceding drop.
  • An object of the present invention is to provide an ink jet printing system having provision for skipping drop intervals when no drops are required for printing and essentially propelling, charging, and deflecting drops only when information is required.
  • Another object of the present invention is to reduce ink jet drop merging and splatter.
  • FIG. 1a illustrates an ink jet printing system incorporating skip logic and including a digital to analog'convertor, shift register, and counter together with a typical nozzle arrangement.
  • FIG. lb is intended for substitution in FIG. 1a and comprises a stairstep generator serving a function comparable to that of the digital to analog convertor and the counter in FIG. 1a.
  • FIG. 2 shows a typical character, such as a capital illustrating some of the drop skipping techniques in the present case.
  • FIGS. 3a3c and FIG. 4a represent various waveforms encountered during the operation of the stairstep generator of FIG. 5.
  • FIG. 4b illustrates timing intervals related to FIG. 4a.
  • FIG. 5 is a circuit diagram of a stairstep generator corresponding to that shown in FIG. lb, while FIG. 6 illustrates a digital to analog convertor corresponding to that shown in FIG. la.
  • FIG. 7 shows a capital "1" showing a non-sequential drop formation and propulsion technique
  • FIGS. 8a and 8b illustrate outputs of the stairstep generator to produce the non-sequential type of operation.
  • a record medium such as a sheet of paper I is positioned for receipt of drops 2a for printing of a character while unused drops 2b are directed to'a gutter 35.
  • Drops are formed by a nozzle assembly 3 having a nozzle and initially forming a stream 2c that passes through acharge electrode 18.
  • Charge electrode 18 is driven by charge electrode driver 21.
  • nozzle assembly 3 includes a crystal 8 that is driven by crystal driver at high frequencies in order to cause drop formation.
  • Ink is provided from a supply tank 5 to nozzle assembly 3 by means of a pump 6.
  • Ink received in gutter 35 is returned by conduit 27 and pump 30 to tank 5.
  • Deflection plate 22 is supplied with a high potential from terminal 25 which remains constant. Plate 23 is grounded at 7. The drops are deflected between the plates on their way to paper 1 in proportion to the charge that they carry.
  • Master clock 11 provides timing signals to machine logic l3 and to crystal driver 15 as well as a character generator 14 during operation of the system. Certain synchronizing signals such as those described in the Hill, et al., application are provided from sync control 40 by line 62. As such vertical column of a character is encountered during printing, character generator 14 provides a drop configuration to shift register No. 1 designated 44.
  • the information in register 44 is shifted to shift register number No. 2 designated 46.
  • the information in the shift registers 44 and 46 is represented in a familiar binary 0 and 1 configuration.
  • the circuits further include a digital to analog convertor 42, a counter 43 and skip logic 47, as well as a gate 52.
  • Counter 43 provides a 6 bit output on bus 54'to convertor 42 representative of the vertical drop location within any 'given'column.
  • Convertor 42 in turn provides a potential to charge electrode driver 21 for charging of the individual drops in order to achieve a degree of deflection between plates 22 and 23 which will insure that the individual drops strike paper 1 in the proper vertical coordinate location. Whether a drop is charged at all or not is determined by whether or not the right-most position 46a of register 46 carries a zero or 1 configuration.
  • counter 43 and shift register 46 are stepped by output pulses from gate 52 on line 55.
  • Gate 52 is conditioned by skip logic 47 under these conditions to pass pulses at the 100 kilo- Ilertz rate on line 60. Whether or not this speed of operation, that is, the normal character printing speed of I00 kiloI-lertz'is maintained is determined by whether or not position 460 of shift register 46 has a one bit in it. In any case where position 46a of shift register 46 has a zero bit, skip logic 47 changes the condition of gate 52 to pass a higher frequency pulse input from line 65 to both shift register 46 and counter 43 in order to rapidly skip such drop intervals since no printing is required.
  • stairstep generator 50 FIG. lb is substituted in FIG. 1a for digital to analog convertor42 and counter 43 by appropriate substitution at interconnecting points 70,-71, and 72 involving the corresponding points 70a, 71a, and
  • stairstep generator 50 is substituted in its entirety for the convertor circuit 42 and counter 43.
  • generator 50 is stepped under normal characterprinting conditions on a drop by drop basis, that is, over a fixed drop voltage interval while in the event of no information in shift register position 46a, stairstep generator 50 is rapidly stepped over a large number of drop intervals corresponding to the number of intervals to be skipped.
  • Charge electrode driver 21 receives a potential from generator 50 representative of the amount of charge to be imparted to the individual drops as they pass through charge electrode 18.
  • DROP SKIPPING TO INCREASE THROUGHPUT -An ink jet printer producing typewriter quality print requires a large matrix or character box.
  • a 40 high by 24 wide character box and an example of a capital T is shown in FIG. 2.
  • the character box In order to allow for underscores and letters with tails such as a small g or small j, the character box must include some area below the T shown in FIG. 2. Similarly, some area above the T is required for accents, the spanish tilde, etc.
  • Drops are placed on the paper by moving an ink jet head from left to right across a page and vertically deflecting the drops as required. If the ink jet operates at a [00 KHz drop formation rate (l0 as per drop) then 40 X 24 960 drops are formed in 9.6 ms to create one character. Note, however, that in the case of the T shown in FIG. 2, only 124 of those 960 drops are actually used. More than percent of the drops in the character box are not used. I
  • the present techniques enable a reduction in the number of drops that are not used and, hence, less time required to form a character. For a given ink drop formation rate,'then, more characters can be formed. Usually no more than 31 drops need to be placed on the paper during one vertical scan for a maximum size character. Two methods have been described above for reducing the number of drops required to print a character. These schemes allow for skipping over the blank space within a vertical stroke, thus using the drops that would normally be directed to the gutter.
  • FIG. 6 is a. schematic diagram of a digital to analog convertor which is an efficient method of driving the charge electrode. Digital logic, shown in FIG. la,
  • Switches C1, C2, C3 C6 are operated by bits one through six respectively of the digital input code.
  • Resistors R1, R2 R6 are binarily related to each other, such that, assuming that the same voltage appears across each resistor, with switch C2 closed,
  • transistor 80 In order for the voltage at the emitter of transistor 80 to rise to the value l2 X Rf, some current from transistor 80 must also flow through resistor 83 to ground. If the gain of the transistor is large then the emitter current, which is the sum of the currents in resistors 81 and 83, is essentially identical to the collector current. The output voltage is then developed across resistor 85; Transistor 80 thus serves as an output buffer for amplifier 47 and allows amplifier 47 to control a load connected to a high voltage power source 87 (+200 V DC).
  • FIG. 5 is a diagram of a modified stairstep generator 50.
  • Timing logic 90 operates analog switch 91.
  • switch 91 When switch 91 is closed for a precisely controlled interval, a current flows through a resistor 93 to the inverting input of operational amplifier 94. However, since the amplifier input is at a virtual ground, the current through resistor 93 flows through capacitor 96, resulting in a charge stored on the capacitor 96 with polarity as shown in FIG. 5. If switch 9l-is'closed during the first 1.25 ,us of each 10 us drop time, the output voltage of amplifier 94 is a stairstep as shown in FIG. 3a.
  • FIG. 3c is a sketch of the output voltage of the circuit at terminal 111.
  • one drop can be sent to the gutter and capacitor 96 charged for up to 10 p.s. In this manner, capacitor 96 steps eight drop positions during this particular drop time. The next drop thus will appear eight drop positions above the last printed drop (assuming that this subsequent drop time also includes a 1.25 as charging time for capacitor 96).
  • Timing logic 90 of FIG. 5 can charge capacitor 96 for intervals less than 10 us but more than 1.25 us. But each such interval wastes one drop so, preferably, no more than one or two such intervals are used per vertical scan.
  • Allowing two special charging times per vertical scan costs two drops and allowing up to 31 drops for printing means that only 33 drops per vertical scan are required. Thus 33 X 24 792 drops are required per character. At an assumed KHZ (10 ,us) drop rate, only 7.92 ms are required to print a character. This technique improves printing speed from 104 cps to I26 cps without any reduction in print quality.
  • the timing logic for the stairstep generator shown as block 90 in FIG. 5, can be easily'implemented using the assumed timing signals produced by logic (not shown) in FIG. 4a.
  • the four fundamentaltiming sequences and their inverses provide eight 100 KHz signals shifted in phase by 45 (1.25 us) increments.
  • FIGS. 2 and 7 represent 40 high by 24 wide character boxes with a capital T shown.
  • the stairstep circuit in FIG. 5 operates as follows:
  • Capacitor 96 has zero charge causing amplifier94 to have zero output voltage. Since the first drop would normally go to row 40, column 12, in the character box (FIG. 7), and that must be blank, switch 99 is closed and the output of the circuit is approximately zero volts. Drop No. 1 goes to the gutter. For'the second drop, switch 91 is closed for 2.5 14s and capacitor 96 charges through resistor 93. The voltage on capacitor 96 would normally be enough to cause drop No. 2 to impact on row 38 in column 12 of FIG. 3. However-, this drop is not needed to print the capital T, so it is sent to the gutter. Capacitor 96 is charged 2.5 #sfor drop No. 3 and again for drop No. 4. They would normally impact in column 12, rows 36 and 34, respectively. But since they are not needed for the T, these drops are sent to the gutter by closing switch 99.
  • FIG. 8a shows the output voltage waveforms of amplifier 94 and the stairstep circuit output for the first cycle.
  • a third advantage of rising the digital to analog convertor, as described above to avoid merging is that the splatter problem is also reduced. All drops overlap about 20 percent, so when one drop overlaps and impacts on the paper, just above the preceding drop, tiny droplets of ink are splattered in the white space around the character and back "toward the high voltage electrodes where they causecontamination. If no two successive drops impact adjacent to each other then more time is available for the ink from the first drops to be absorbed by the paper before the adjacent drops arrive.
  • an arrangement for increasing throughput during printing of information on a record medium comprising:
  • nozzle means for forming and propelling a plurality of ink jet drops toward said record medium, means for charging said ink drops with code representations, means for deflecting said ink drops in accordance with the charge on said drops, said drops being deflected in successive vertical columns, each column comprising a predetermined number of drop locations;
  • a data source for providing code representations for information to be printed, each code representation being indicative of a drop to be printed or not to be printed;
  • register means connected to said data source for storing said code representations
  • control means operable in one mode to supply control signals to said nozzle means, said data source, said register means and said interconnecting means at a predetermined rate during printing of information and operable in another mode to supply control signals at a higher rate;
  • skip means for connecting said predetermined rate control signals to said register means and said interconnecting means at said predetermined rate during the printing of information and responsive to said skip signal for connecting said higher rate control signals to said register means and said interconnecting means in order to skip non-information code representations.
  • control means includes:
  • clock circuit providing a pulse output at a first predetermined relatively slower rate for activating said circuits during printing of information and said clock circuit further providing pulse signals at a relatively higher rate for activating said circuits in order to skip non-information representations.
  • interconnecting means comprises a counter for keeping track of drop locations within each vertical column
  • a digital to analog convertor for converting said code representations to potentials required for charging said drops.
  • means include: l
  • said skip means includes:
  • ing means includes:
  • a stairstep generator providing stepped output potential levels respectively representative of drop locations within each of said vertical columns, said stairstep generator being stepped at a low rate during printing and at a relatively high rate when noninformation code representations are detected.
  • an arrangement for reducing-drop merging and splatter comprising:
  • nozzle means for forming and propelling a plurality of ink jet drops toward said record medium, means for charging said ink drops with code representations, means for deflecting said ink drops in accordance with the charge on said drops, said drops being deflected in successive vertical columns, each column on said record medium comprising a set of a predetermined number of drop locations; cycling means operable in at least two cycles for each column of printing for controlling said nozzle means and said charging means; said cycling means being operable in at: least a first cycle of operation for controlling said nozzle means and said charging means to selectively propel said ink jet drops toward selected ones only of said drop locations on said record medium comprising less than a set of drop locations, and said cycling means being further operable in another of said at least two cycles for controlling said nozzle means and charging means to selectively-propel said ink jet drops toward other drop locations on said record medium not previously selected in said first cycle of said at least two cycles of operation, said other drop locations comprising the remainder of a set of drop 10- cations for each said column.
  • said cycling means comprises a stairstep generator.
  • cycling means comprises a digital to analog convertor and associated counter means.

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US00297546A 1972-10-13 1972-10-13 Increasing throughput in ink jet printing by drop skipping and reducing ink jet merging and splatter using a stairstep generator Expired - Lifetime US3769631A (en)

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US (1) US3769631A (de)
JP (1) JPS5230329B2 (de)
CA (1) CA978583A (de)
DE (2) DE2343420C3 (de)
FR (1) FR2206707A5 (de)
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Cited By (13)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3895386A (en) * 1974-07-29 1975-07-15 Dick Co Ab Control of drop printing
US3925790A (en) * 1974-04-25 1975-12-09 Rca Corp Image generator having a plurality of marker units operated in a predetermined sequence to inhibit the formation of patterns
US3929071A (en) * 1974-12-23 1975-12-30 Ibm Ink recirculating system for ink jet printing apparatus
US3964591A (en) * 1975-06-10 1976-06-22 International Business Machines Corporation Font selection system
US4034379A (en) * 1972-11-13 1977-07-05 Teletype Corporation Ink jet writing process and apparatus
US4054882A (en) * 1973-01-22 1977-10-18 International Business Machines Corporation Non-sequential ink jet printing
US4322732A (en) * 1978-08-12 1982-03-30 Ricoh Co., Ltd. Ink jet recording method
US4381513A (en) * 1979-05-10 1983-04-26 Ricoh Co., Ltd. Deflection plates for electrostatic ink-jet printer
US4472722A (en) * 1980-02-18 1984-09-18 Ricoh Company, Ltd. Ink jet printing method
US5790150A (en) * 1994-02-17 1998-08-04 Colorspan Corporation Method for controlling an ink jet printer in a multipass printing mode
US6016205A (en) * 1997-08-22 2000-01-18 Xerox Corporation Ink-jet copier in which an original image is prescanned for optimized printing
US6312076B1 (en) * 1997-05-07 2001-11-06 Seiko Epson Corporation Driving waveform generating device and method for ink-jet recording head
WO2019056790A1 (zh) * 2017-09-22 2019-03-28 京东方科技集团股份有限公司 喷墨打印喷头、喷墨量测量系统和方法及喷墨量控制方法

Families Citing this family (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2402541C3 (de) * 1973-01-22 1981-11-12 International Business Machines Corp., 10504 Armonk, N.Y. Steuersystem für einen Tintenstrahldrucker
US4059183A (en) * 1976-12-30 1977-11-22 International Business Machines Corporation Dot matrix printer with slanted print head and modular skewing of dot pattern information
JPS5830826B2 (ja) * 1978-06-29 1983-07-01 シャープ株式会社 インクジェットプリンタのインク供給装置
US4395717A (en) * 1980-03-07 1983-07-26 Ricoh Company, Ltd. Ink jet recording apparatus
JPS56150565A (en) * 1980-04-24 1981-11-21 Sharp Corp Forming method for dot row of ink jet printer
WO1990012690A1 (en) * 1989-04-20 1990-11-01 Leningradsky Institut Tochnoi Mekhaniki I Optiki Electric drop-jet printing device

Cited By (16)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4034379A (en) * 1972-11-13 1977-07-05 Teletype Corporation Ink jet writing process and apparatus
US4054882A (en) * 1973-01-22 1977-10-18 International Business Machines Corporation Non-sequential ink jet printing
US3925790A (en) * 1974-04-25 1975-12-09 Rca Corp Image generator having a plurality of marker units operated in a predetermined sequence to inhibit the formation of patterns
US3895386A (en) * 1974-07-29 1975-07-15 Dick Co Ab Control of drop printing
US3929071A (en) * 1974-12-23 1975-12-30 Ibm Ink recirculating system for ink jet printing apparatus
DE2552513A1 (de) * 1974-12-23 1976-07-01 Ibm Tintenumwaelzeinrichtung an einem tintenstrahldrucker
US3964591A (en) * 1975-06-10 1976-06-22 International Business Machines Corporation Font selection system
US4322732A (en) * 1978-08-12 1982-03-30 Ricoh Co., Ltd. Ink jet recording method
US4381513A (en) * 1979-05-10 1983-04-26 Ricoh Co., Ltd. Deflection plates for electrostatic ink-jet printer
US4472722A (en) * 1980-02-18 1984-09-18 Ricoh Company, Ltd. Ink jet printing method
US5790150A (en) * 1994-02-17 1998-08-04 Colorspan Corporation Method for controlling an ink jet printer in a multipass printing mode
US6312076B1 (en) * 1997-05-07 2001-11-06 Seiko Epson Corporation Driving waveform generating device and method for ink-jet recording head
US6474762B2 (en) 1997-05-07 2002-11-05 Seiko Epson Corporation Driving waveform generating device and method for ink-jet recording head
US6016205A (en) * 1997-08-22 2000-01-18 Xerox Corporation Ink-jet copier in which an original image is prescanned for optimized printing
WO2019056790A1 (zh) * 2017-09-22 2019-03-28 京东方科技集团股份有限公司 喷墨打印喷头、喷墨量测量系统和方法及喷墨量控制方法
US10751992B2 (en) 2017-09-22 2020-08-25 Boe Technology Group Co., Ltd. Inkjet printing spray head, inkjet amount measuring system and method and inkjet amount controlling method

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JPS5230329B2 (de) 1977-08-08
IT993444B (it) 1975-09-30
GB1385137A (en) 1975-02-26
DE2366097C3 (de) 1979-09-06
DE2343420C3 (de) 1978-12-14
DE2343420B2 (de) 1978-04-13
CA978583A (en) 1975-11-25
JPS49101468A (de) 1974-09-25
DE2366097B2 (de) 1979-01-11
DE2343420A1 (de) 1974-04-25
FR2206707A5 (de) 1974-06-07

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