US3789422A - Ink drop coupling capacitance compensation - Google Patents

Ink drop coupling capacitance compensation Download PDF

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Publication number
US3789422A
US3789422A US00291124A US3789422DA US3789422A US 3789422 A US3789422 A US 3789422A US 00291124 A US00291124 A US 00291124A US 3789422D A US3789422D A US 3789422DA US 3789422 A US3789422 A US 3789422A
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Prior art keywords
drop
drops
circuit
charging
electrode
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Expired - Lifetime
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US00291124A
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English (en)
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J Haskell
S Tsao
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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
    • B41J2/12—Ink jet characterised by jet control testing or correcting charge or deflection

Definitions

  • FIG. 4a is a diagrammatic representation of FIG. 4a
  • FIG. 11 FIG. 12
  • the invention relates to ink drop printing and it has reference in particular to the generation of the proper charging voltage such that accurate compensation for the drop coupling capacitance distortion is achieved.
  • Another object of this invention is to provide for' using storage means to provide for modifying the charge on an ink drop being formed in an ink drop printer in accordance with the charges on one or more ink drops which have just previously been charged.
  • Yet another object of the invention is to provide for modifying the charge on an ink drop being formed in accordance with a voltage defined by the equation where K is the number"bttiiEsfiihavifig a non-- negligible coupling capacitance'with the drop being formed.
  • Still another object of the invention is to provide for detecting if one or more previously formed drops ofink in an ink jet printer have been charged and for modifying the charge on a drop currently being formed in accordance with the greater of two or more modifying voltages dependent on the charges on said previously charged drops.
  • Another important object of the invention is to provide in an ink drop printer for modifying the charge on a drop just being formed so as to substantially neutralize the capacitance effects on said drop of drops previously charged and thereby insure accurate positioning of said drop being formed.
  • Yet another object of the invention is to provide for connecting a character generator charging electrode signal source to the charging electrode in an ink drop printer through a plurality of circuits each of which apply different functions of the charging electrode signal to the charging electrode.
  • Still another important object of the invention is to provide in an ink drop printer for utilizing a plurality of delay means having different characteristics to modify the charging signal at the instant of forming one drop in accordance with the charging signals at the instance of forming one or more previously formed drops.
  • FIG. 3 is a schematic circuit diagram of a compensated charging circuit embodying the invention in a different form
  • FIGS. 4a 4d show curves illustrating the voltage relations in FIG. 3;
  • FIG. 5 is a schematic circuit diagram of a compensated charging circuit diagram embodying the invention in another form
  • FIG. 6 is a schematic circuit diagram of a compensated charging circuit embodying the invention in yet another form
  • FIG. 7a is a circuit diagram of a R-C compensating network
  • FIG. 7b is a waveform of a typical input signal
  • FIG. is a waveform of the resulting output signal from the R-C compensating network
  • FIG. 8 is a schematic block diagram of a compensating circuit'embodying the R-C network of FIG. 6a;
  • FIGS. 9a 9d show waveforms for the circuit of FIG.
  • FIG. 10 is a table of compensated charging amplitude voltage values for first and second order compensation according to the formulas of the invention.
  • FIG. 11 is a typical uncompensated staircase waveform of a charge amplitude control used with the circuit of FIG. 5 to provide the compensated values of the table in FIG. 9;
  • FIG. 12 is a schematic showing of the WXYZ voltage divider of FIG. 6 showing the calculated values of resistance to give the voltage values of the table in FIG. 9.
  • the Stream 1 and the numerals 3 and,4 designate drops which have previously broken off.
  • the numeral 5 designates a charging electrode for placing a charge on the drops as they are formed for deflecting them in accordance with a predetermined pattern onto a record or the like.
  • the reference numeral 6 designates generally a source of voltage for the charging electrode 5. The following is a generalized derivation for the modified voltage pulse to be applied to a drop being formed in order to accurately position it on the document.
  • C 's are the coefficients of capacitance and C s, i a j, are the coefficients of electrostatic induction.
  • C u S are called direct capacitances and in particular, Ci 's are self-capacitances.
  • D and I (t) may be set to zero or at ground level since Equation (2) clearly implies that the charges only depend on the relative voltage potentials of the conductors.
  • Equation (3) Combining Equation (3) into Equation (5) and solve for 0) and I explicitly Now substitute the above values for D 0) and D 0) into the expression for q (t) in Equation (3) q (t) u s) 2-5 40) zsfl') 4 ri e
  • f( t) is in some proportion to the intended deflection of the droplet presently being formed, then its resulting charge would not be proportional to the deflection as intended.
  • Equation (9) Considering the fact that the sequence of droplets are formed at apart in time, the phenomenon described by Equation (9) maybe written as a second order difference equation 1 where (II) and coefficients D f, and D corresponds to the obvious terms in Equation (9). From Equation (10),
  • Equation (12) From physical arguments one can conclude for the configuration of FIG. 1 that 1 D, D in fact, one estimate of a particular configuration which also has been substantiated be experiments puts the values of D and D at 0.15 and 0.05, respectively. Thus, some terms in Equation (14) clearly have only a minor influence on the value of q" From engineering point of view it is desired that 11"" be proportional to f lAn obvious solution is to modify the charging voltage before it is applied to the charging electrode.
  • the reference numeral denotes a stored character generator circuit for applying a deflection signal to a Charging Electrode 5.
  • a Compensating Circuit 14 is connected between the stored Character Generator 10 and the Charging Electrodes 5.
  • the compensation circuit 14 may comprise a Resistor 16 connecting the stored Character Generator 10 to the Charging Electrode 5 for applying a voltage to the Charging Electrode 5 without time delay in accordance with the actual signal from the stored Character Generator 10.
  • compensation storage means such as a shift register or a Delay Circuit 18 may be connected in parallel with the Resistor 16.
  • the Delay Circuit 18 has a delay equal to 0-1 which is the time interval between the drops.
  • Resistor 20 Connected in series with the Delay Circuit 18 is a Resistor 20 having a value equal to R /B, where R is the value of Resistor 16. This provides a compensating voltage which is dependent on the charging voltage applied to the previous drop which occurred 0-! ahead of the drop just being formed. Additional compensation may be supplied by one or more additional delay circuits such as the Delay Circuit 22 having a delay equal to 20'! and which is connected to the charging electrode 5 through a resistor having a value Ru/Bg- This circuit provides compensation in accordance with the second drop ahead of the drop currently being formed.
  • the Resistor l6, Delay Circuit 18 and Delay Circuit 22 may be connected to a Summing Circuit 24 for applying the resulting voltage to the Charging Electrode 5 through an operational 6 Amplifier 26 having a feedback circuit comprising a Resistor 28 having a value equal to ax R
  • a Compensating Circuit 30 connects the Character Generator 10 to the Charging Electrode 5.
  • the Compensating Circuit 30 comprises Delay Circuits 32 and 34, each having a delay equal to at and connected in series circuit relation.
  • An adjustable Rheostat 36 connects a point between the two delay circuits to the Charging Electrode 5 through an Amplifier and Adder Circuit 38.
  • a second Rheostat 40 connects the Delay Circuit 34 to the charging electrode through the Amplifier and Adder 38. Additional delay circuit may be added on when needed.
  • a Conductor 42 provides a direct connection from the character generator to the Charging Electrode 5 through the Amplifier and Adder 38. Accordingly, each time a signal is applied from the Character Generator 10 to the Charging Electrode 5, at the same time delayed signals will be applied to the Charging Electrode 5 from the Delay Circuits 32 and 34, which are representative of the charges on previously charged drops which were generated (rt and 20! ahead of the drop currently being charged.
  • the curves in FIGS. 40 through 4d show the resulting compensated charging signal in FlG. 4d generated from an original charging signal shown in FIG. 4a.
  • the reference numeral 44 designates a nozzle having a Transducer 46 for vibrating the nozzle to cause a stream of Ink 1 issuing from the nozzle tobreak up into dropswhich are charged by a Charging Electrode 5 and deflected by Deflection Electrodes 48 either into a Gutter 50 or onto a Document 52 for printing thereon.
  • a Charge Amplitude Control Circuit 54 which may, for example, produce a staircase type signal, as shown, to the Charging Electrode 5 in conjunction with character generating signals from a Character Generation System 56, which provides a pulse output characteristic of predetermined characters
  • the Charge Amplitude Control Circuit 54 may be connected to a Charging Electrode Driver 58 through AND gate 60 and a maximum priority OR circuit 62.
  • a Voltage Divider 64 comprising Resistors 66 and 68 is connected between the Charge Amplitude Control Circuit 54 and ground at a point X. Point Y between the Resistors 66 and 68 is connected to the OR circuit 62 through AND gate 72.
  • a two-position Shift Register 74 is connected to the Character Generator Circuit 56 and is connected to be advanced by a Droplet Generation Frequency Source 76, which is alsovconnected to the Transducer 46 for producing the ink drops. Stage A of the Shift Register 74 is connected to the AND 72, aswell as the AND 60, while Stage B is connected to the AND 60 only.
  • the Resistors 66 and 68 are so proportioned that the output at X equals f(t)+fi,f( t0r) and the output Y equals f(t).
  • the output Y corresponds to the signal normally applied to the charging electrode 5 as an uncompensated signal, while the signal at X corresponds to the signal to be applied to the Charging Electrode 5 compensated in accordance with the charge on a previous drop, which can be readily determine with a uniform staircase signal of the type being used.
  • the charge on each drop being formed is compensated in accordance with the value of the charge on a previous drop, if the previous drop was charged,
  • the Shift Register 74 determines whether or not the previcompensated signal voltage will be gated through the AND 72 and OR 62 for application to the Charging Electrode 5.
  • a 3-p0sition Shift Register 80 is utilized in conjunction with AND circuits 82, 84, 86, 88 and a maximum priority OR circuit 90 for applying compensated charging signals to a Charging Electrode 5 through a Driver 58 under the control of a Character Generation Circuit 56 and a Droplet Generation Frequency Source 76.
  • the Charge Amplitude Control Circuit 54 is connected directly to the AND 82 and to a Voltage Divider 92 comprising Resistors 93, 94, 95 and 96 providing voltages at the WXYZ points in accordance.
  • a Compensating Network 100 is shown similar to that described in the article by R. G. Sweet, hereinbefore referred to.
  • the network comprises a capacitor C connected with a resistor R2 in a T network having a resistor R connected between the input and output terminals of one leg.
  • This network when provided with input waveform, such as shown in FIG. 7b modifies the waveform to provide the output shown in FIG. 70.
  • the disadvantage of such a network is that exact compensation occurs only at one instant of the clock cycle, whereas the droplet may separate at any time during this cycle.
  • a typical Compensating Network 100 is connected between a Source 102 of clock signals and a non-sequential Scan Character Generation Circuit 104 and a Charging Electrode Driver 58 for applying a charging signal to a Charging Electrode 5.
  • a Sample and Hold circuit 106 is connected between the Sweet Network 100 and the Charging Electrode Driver 58.
  • This circuit is controlled by a Sample Gate 108 and a Delay Circuit 110 so that the Sweet Network 100 output is gated to the Charging Electrode 5 at the exact instant of correct compensation.
  • the Delay Circuit 110 is provided to insure the Sample Gate 108 occurs at the correct time relative to the Character Generator output. Timing relations are shown by the typical waveforms of FIGS. 9a through 9e.
  • FIG. 10 shows a table of charging voltage values obtained at the junctions W, X, Y and Z in the circuit of FIG. 6, when utilizing an uncompensated staircase signal such as shown in FIG. 11.
  • the values of the Resistors 93 through 96 are shown in'FIG. 12 for obtaining the values in the table of FIG. 10.
  • a typical value for R is 1000 ohms.
  • circuit means connecting video means to said electrode means to apply signals thereto to selectivelycharge different ones of said ink drops to deflect said ink drops in accordance with predetermined video signals to position selected ones of said drops on said recording medium in a predetermined pattern
  • compensation means including storage means connected between said circuit means and said electrode means for detecting the charges on previous drops and modifying the video signal from said circuit means for charging a'particular drop in accordance with the equation V(! oz ⁇ f(r) ,B,f(trrr) 2 o w here V6) is the compensated charging voltage function; at is the drop generation period; and a is a scaling or amplitude constant; to minimize the effects of said previous drop charges on said particular drop.
  • compensation means including a voltage divider having sections proportioned according to the terms of t e sq a ter M f M 32]"(1 2oz) abuses tea betweeii'saicl circuit means and ground, and gate means controlled in accordance with the charge condition of previous drops connecting different sections of said voltage divider to, said charging electrode.
  • circuit means connecting video means to said electrode means to apply signals thereto to selectively charge different. ones of said ink drops to deflect said ink drops in accordance with predetermined video signals to position selected ones of said drops on said recording medium in a predetermined pattern, and
  • compensation means including a RC network and a ticular drop.

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  • Particle Formation And Scattering Control In Inkjet Printers (AREA)
  • Electrostatic Spraying Apparatus (AREA)
  • Fax Reproducing Arrangements (AREA)
US00291124A 1972-09-21 1972-09-21 Ink drop coupling capacitance compensation Expired - Lifetime US3789422A (en)

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US29112472A 1972-09-21 1972-09-21

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US (1) US3789422A (enrdf_load_stackoverflow)
JP (1) JPS5225286B2 (enrdf_load_stackoverflow)
BE (1) BE803943A (enrdf_load_stackoverflow)
CA (1) CA982208A (enrdf_load_stackoverflow)
CH (1) CH556580A (enrdf_load_stackoverflow)
ES (1) ES418945A1 (enrdf_load_stackoverflow)
FR (1) FR2200780A5 (enrdf_load_stackoverflow)
GB (1) GB1429017A (enrdf_load_stackoverflow)
IT (1) IT992693B (enrdf_load_stackoverflow)
NL (1) NL7312748A (enrdf_load_stackoverflow)
SE (1) SE391598B (enrdf_load_stackoverflow)

Cited By (15)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3828354A (en) * 1973-09-27 1974-08-06 Ibm Ink drop charge compensation method and apparatus for ink drop printer
FR2233183A1 (enrdf_load_stackoverflow) * 1973-06-18 1975-01-10 Ibm
US3946399A (en) * 1974-11-15 1976-03-23 A. B. Dick Company Charge compensation network for ink jet printer
US3947853A (en) * 1972-10-12 1976-03-30 International Business Machines Corporation Subscripting, superscripting, and character height compression in ink jet printing apparatus
US4032924A (en) * 1974-10-31 1977-06-28 Nippon Telegraph And Telephone Public Corporation Distortion reduction in ink jet system printer
US4080606A (en) * 1975-05-09 1978-03-21 Hitachi, Ltd. Ink jet printer
US4107698A (en) * 1977-02-10 1978-08-15 International Business Machines Corporation Ink jet printer apparatus and method of operation
US4157551A (en) * 1974-10-31 1979-06-05 Nippon Telegraph And Telephone Public Corporation Distortion reduction in ink jet system printer
US4229749A (en) * 1979-03-26 1980-10-21 International Business Machines Corporation Ink drop compensation based on print-data blocks
EP0020984A1 (en) * 1979-06-29 1981-01-07 International Business Machines Corporation Ink jet printing system and method of generating liquid droplets
US4310845A (en) * 1979-03-26 1982-01-12 International Business Machines Corporation Ink drop compensation based on dynamic, print-data blocks
US4321607A (en) * 1980-06-17 1982-03-23 International Business Machines Corporation Scaling aerodynamic compensation in an ink jet printer
US4427986A (en) 1981-04-17 1984-01-24 Fuji Xerox Co., Ltd. Method of charging jetted ink drops
US4490729A (en) * 1982-09-15 1984-12-25 The Mead Corporation Ink jet printer
US4812673A (en) * 1987-07-17 1989-03-14 Burlington Industries, Inc. Print pulse control circuit for electrostatic fluid jet applicator

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS53109192A (en) * 1977-03-04 1978-09-22 Japan National Railway Method of reducing stress concentration of wire and terminal connector
JPS5820574U (ja) * 1981-07-30 1983-02-08 三菱電機株式会社 スピ−カシステムのネットワ−ク

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3476874A (en) * 1966-11-08 1969-11-04 Arthur V Loughren Controlled ink-jet copy-reproducing apparatus
US3512173A (en) * 1967-12-28 1970-05-12 Xerox Corp Alphanumeric ink droplet recorder
US3631511A (en) * 1970-05-08 1971-12-28 Dick Co Ab Drop charge compensated ink drop video printer

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3476874A (en) * 1966-11-08 1969-11-04 Arthur V Loughren Controlled ink-jet copy-reproducing apparatus
US3512173A (en) * 1967-12-28 1970-05-12 Xerox Corp Alphanumeric ink droplet recorder
US3631511A (en) * 1970-05-08 1971-12-28 Dick Co Ab Drop charge compensated ink drop video printer

Cited By (17)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3947853A (en) * 1972-10-12 1976-03-30 International Business Machines Corporation Subscripting, superscripting, and character height compression in ink jet printing apparatus
FR2233183A1 (enrdf_load_stackoverflow) * 1973-06-18 1975-01-10 Ibm
US3828354A (en) * 1973-09-27 1974-08-06 Ibm Ink drop charge compensation method and apparatus for ink drop printer
US4157551A (en) * 1974-10-31 1979-06-05 Nippon Telegraph And Telephone Public Corporation Distortion reduction in ink jet system printer
US4032924A (en) * 1974-10-31 1977-06-28 Nippon Telegraph And Telephone Public Corporation Distortion reduction in ink jet system printer
US3946399A (en) * 1974-11-15 1976-03-23 A. B. Dick Company Charge compensation network for ink jet printer
US4080606A (en) * 1975-05-09 1978-03-21 Hitachi, Ltd. Ink jet printer
US4107698A (en) * 1977-02-10 1978-08-15 International Business Machines Corporation Ink jet printer apparatus and method of operation
FR2380141A1 (fr) * 1977-02-10 1978-09-08 Ibm Imprimante a projection d'encre
US4310845A (en) * 1979-03-26 1982-01-12 International Business Machines Corporation Ink drop compensation based on dynamic, print-data blocks
US4229749A (en) * 1979-03-26 1980-10-21 International Business Machines Corporation Ink drop compensation based on print-data blocks
EP0020851A1 (en) * 1979-03-26 1981-01-07 International Business Machines Corporation Ink jet printers with ink drop compensation and method of ink drop compensation
EP0020984A1 (en) * 1979-06-29 1981-01-07 International Business Machines Corporation Ink jet printing system and method of generating liquid droplets
US4321607A (en) * 1980-06-17 1982-03-23 International Business Machines Corporation Scaling aerodynamic compensation in an ink jet printer
US4427986A (en) 1981-04-17 1984-01-24 Fuji Xerox Co., Ltd. Method of charging jetted ink drops
US4490729A (en) * 1982-09-15 1984-12-25 The Mead Corporation Ink jet printer
US4812673A (en) * 1987-07-17 1989-03-14 Burlington Industries, Inc. Print pulse control circuit for electrostatic fluid jet applicator

Also Published As

Publication number Publication date
IT992693B (it) 1975-09-30
FR2200780A5 (enrdf_load_stackoverflow) 1974-04-19
NL7312748A (enrdf_load_stackoverflow) 1974-03-25
ES418945A1 (es) 1976-03-01
JPS5225286B2 (enrdf_load_stackoverflow) 1977-07-06
DE2346059A1 (de) 1974-04-11
CH556580A (de) 1974-11-29
DE2346059B2 (de) 1977-04-14
JPS49101460A (enrdf_load_stackoverflow) 1974-09-25
CA982208A (en) 1976-01-20
GB1429017A (en) 1976-03-24
BE803943A (fr) 1973-12-17
SE391598B (sv) 1977-02-21

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