EP0836943A2 - Imprimante et tête électrostatique à jet d'encre - Google Patents

Imprimante et tête électrostatique à jet d'encre Download PDF

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Publication number
EP0836943A2
EP0836943A2 EP97118084A EP97118084A EP0836943A2 EP 0836943 A2 EP0836943 A2 EP 0836943A2 EP 97118084 A EP97118084 A EP 97118084A EP 97118084 A EP97118084 A EP 97118084A EP 0836943 A2 EP0836943 A2 EP 0836943A2
Authority
EP
European Patent Office
Prior art keywords
ink
orifices
electrode
orifice
ink jet
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.)
Withdrawn
Application number
EP97118084A
Other languages
German (de)
English (en)
Other versions
EP0836943A3 (fr
Inventor
Kazuo Shima
Junichi Suetsugu
Tadashi Mizoguchi
Hitoshi Minemoto
Hitoshi Takemoto
Yoshihiro Hagiwara
Toru Yakushiji
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
NEC Corp
Original Assignee
NEC Corp
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by NEC Corp filed Critical NEC Corp
Publication of EP0836943A2 publication Critical patent/EP0836943A2/fr
Publication of EP0836943A3 publication Critical patent/EP0836943A3/fr
Withdrawn legal-status Critical Current

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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
    • 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
    • B41J2/015—Ink jet characterised by the jet generation process
    • B41J2/04—Ink jet characterised by the jet generation process generating single droplets or particles on demand
    • B41J2/06—Ink jet characterised by the jet generation process generating single droplets or particles on demand by electric or magnetic field
    • 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
    • B41J2/015—Ink jet characterised by the jet generation process
    • B41J2/04—Ink jet characterised by the jet generation process generating single droplets or particles on demand
    • B41J2/06—Ink jet characterised by the jet generation process generating single droplets or particles on demand by electric or magnetic field
    • B41J2002/061—Ejection by electric field of ink or of toner particles contained in ink

Definitions

  • the present invention concerns an electrostatic ink jet recording head of depositing a charged particulate material in a liquid ink carrier to a recording medium under the effect of an electrostatic force to conduct recording and, more in particular, it relates to an electrostatic ink jet recording and a recording device head for attaining the lowing of a driving voltage.
  • an electrostatic ink jet recording device described in PCT Publication Number WO93/11866, has an electrostatic ink jet recording head and an opposite electrode.
  • the opposite electrode is disposed at the back of a recording sheet of paper for forming an electric field with respect to the ink jet recording head.
  • the ink jet recording head has an ink chamber for temporarily storing liquid ink supplied, for example, from an ink tank.
  • An ejection electrode is formed at the end of the ink chamber and driven for discharging the ink.
  • a top end of the ejection electrode is opposed to the opposite electrode.
  • the liquid ink in the ink chamber is supplied by its surface tension as far as the top end of the ejection electrode, by which an ink meniscus is formed at the top end of the ejection electrode.
  • the liquid ink used for the ink jet recording head contains a charged particulate material for forming a color.
  • the charged particulate material is hereinafter referred to as toner particles.
  • the toner particles are charged positively by a zeta potential but the liquid ink is kept electrically neutral under the state in which no voltage is applied to the ejection electrode.
  • the polarity of the zeta potential is determined depending on the characteristics of the toner particles.
  • Japanese Patent Laid-Open Sho 58-153661 issued on September 12, 1983 discloses an electrostatic ink jet recording head of a reduced thickness.
  • an ink jet recording head has a base substrate 15, and a nozzle plate 10 fixed on the base substrate 15.
  • a plurality of nozzles N11 to N5n for ejecting an ink are formed in the nozzle plate 10 in two dimensional directions X-Y.
  • An ink chamber 12 is formed between the nozzle plate 10 and the base substrate 15.
  • the plurality of nozzles protrude cylindrically from the surface of the nozzle plate 10.
  • a plurality of first electrodes 11 in parallel with each other are formed in the nozzle plate 10 in the direction Y.
  • the plurality of the first electrodes 11 connect nozzles N11 to N51, N12 to N52, ... , N1n to N5n in the direction Y in common respectively.
  • One end of each of the first electrodes 11 is connected with the terminals from T1 to Tn respectively and printing signals are supplied to each of the terminals individually.
  • second electrodes D1 to D5 are formed in the direction X on the base substrate 15. As shown in fig. 2 and Fig. 3, the second electrodes D1 to D5 are formed at the bottom of the ink chamber 12 under the nozzle plate 10.
  • the first electrodes 11 are at a common potential in the direction Y (feeding direction of recording paper), while the second electrodes D1 to D5 disposed below the first electrode 11 are common electrodes for the nozzles N11 to N5n in the direction X.
  • a recording sheet of paper not illustrated is disposed ahead of the nozzles N11 to N5n, and an opposite electrode not illustrated is disposed at the back of the recording sheet of paper.
  • An ink polarizing force is applied by a voltage provided between the first electrodes 11 and the second electrodes D1 to D5 to move a toner material in the ink to the nozzle, and a coulomb force is generated by the voltage between the first electrode 11 and the opposite electrode. Then, ink droplet flies from one of the nozzles N11 to N5n to the recording sheet of paper.
  • the thickness of the electrostatic ink jet recording head is reduced in the ink ejecting direction.
  • the surface tension is large at the top end face of the nozzle and an electric field strong enough to eject the ink from the aperture overriding the surface tension has to be applied between the opposite electrode and the first electrode 11.
  • An object of the present invention is to provide an electrostatic ink jet device and a recording head which has small surface tension at an ejecting portion and stabilizes the flying of toners.
  • an electric field is given to an ink in which charged toner particles are dispersed and the toner particles are ejected by the electrostatic force generated from the electric field thereby conducting ink setting.
  • the recording head has an orifice plate formed with a plurality of orifices each having a small aperture, an ejection electrode disposed to the orifice plate and located in adjacent with each of the orifices, a base plate having a chamber secured being opposed to the orifice plate for storing an ink and supplying the thus stored ink to the orifice, and an insulative protrusion member disposed in the chamber and having convex portions formed in correspondence to the orifices, with the top end of each convex portion being protruded penetrating the individual orifice.
  • the top end of the convex portion of the protrusion member protrudes passing through the orifice, it is possible to prevent the ink meniscus from retracting into the orifices to form a concave portion after the flying of the ink droplet.
  • the ejection electrode may be formed on a surface of the orifice plate so as to surround the periphery of each of the orifices and may be coated with an insulation film.
  • an electrophoretic electrode is formed so as to be electrically in liquid contact with the ink in the chamber on the surface opposed to a plurality of orifices of the base plate.
  • the protrusion member extends from the electrophoretic electrode toward the orifices.
  • toner particles in the chamber move along the protrusion member to the orifices thereby enabling to increase the degree of concentration of the toner particles to the orifices. That is, the protrusion member serves as a guide for moving the toner particles into the orifices.
  • an electrostatic ink jet printing head 100 in a preferred embodiment according to the present invention has an orifice plate 2 formed with a plurality of orifices 1 each having small apertures, and a base plate 5 opposed to and supporting the orifice plate 2.
  • the base plate 5 supports the orifice plate 2 and has a chamber 4 which is for storing an ink 3. The portion above the chamber 4 covered with the orifice plate 2.
  • two protrusion members 6 are secured to the bottom of the base plate 5 by way of an electrophoretic electrode 20 formed in the direction X in Fig. 4.
  • Each of the protrusion members 6 is formed with a thin plate-like insulation material, convex portions 6a are formed at pitches identical with those of the orifices 1, and the top ends of the convex portions 6a are respectively protruded from respective orifices 1.
  • the orifice plate 2 is formed of a thin-sheet insulating material.
  • the orifice 1 formed in the orifice plate 2 has a plurality of fine apertures formed at an identical interval with a desired dot pitch.
  • Fig. 6 is a perspective view enlarged for a portion T in Fig. 4, and Fig. 7 is a perspective view illustrating the state at the back of Fig. 6.
  • the top end of each of the convex portion 6a of the protrusion member 6 has a shape smaller than the diameter of the orifice 1.
  • An ejection point 40 for ejecting an ink is disposed at the top end of each convex portion 6a of the protrusion member 6 so as to protrude from each orifice 1 of the orifice plate 2 by a desired amount to the opposite electrode not illustrated in Fig. 6 (hereinafter referred to as an ejection point 40).
  • a plurality of ejection electrodes 7 made of a metal material such as Ni or Al formed is formed as a pattern so as to surround each of the orifices 1 independent of each other, at the back of the orifice plate 2 (the surface on the side of the chamber 4 in Fig. 5A) by a thin film forming process.
  • the ejection electrodes 7 may be formed on the surface of the orifice plate 2.
  • Fig. 8 is a cross sectional view taken along line C-C in Fig. 6 and Fig. 9 is a cross sectional view taken along line D-D in Fig. 6.
  • the surface of the ejection electrode 7 formed on the rear face of the orifice plate 2 is coated with an insulative resin 9. This prevents direct contact of the ink 3 in the chamber 4 with the ejection electrode 7.
  • the base plate 5 is a member made of insulating material and formed by molding or machining, and supports the orifice plate 2 from the back. Further, an ink supplying aperture 30 and ink discharging apertures 31 for circulating the ink 3 in the chamber 4 are formed to the base plate 5. Each of the protrusion members 6 is fixed between the ink supplying aperture 30 and the ink discharging apertures 31. Further, the electrophoretic electrode 20 is formed in the chamber 4 on the surface opposed to the orifice plate 2 and made of a metal material such as Cu capable of electric liquid contact with the ink 3 in the chamber 4.
  • the ink 3 in the chamber 4 comprises a toner ink having charged toner particles as a colorant dispersed in a liquid carrier, which is supplied from a not illustrated ink tank by way of a not illustrated pump from the ink supplying aperture 30 to the chamber 4 in the printing head and, further, recovered from the ink discharging apertures 31 to the not illustrated ink tank and then supplied again into the chamber 4 in the printing head.
  • the ink 3 is always circulated between the ink tank and the chamber 4 in the printing head.
  • the ink 3 supplied to the chamber 4 is maintained on each of the orifices 1 in the orifice plate 2 while forming an independent ink meniscus of a convex shape with the ejection point 40 as an apex.
  • Fig. 10 is a cross sectional view of an electrostatic ink jet recording device having the ink jet printing head 100 of Fig. 4.
  • the state of the ink jet printing head 100 is identical with that in Fig. 8.
  • An opposite electrode 25 is disposed at a position opposing the orifice plate 2 of the ink jet printing head 100 by way of a constant gap from the ejection point 40.
  • a recording sheet of paper 26 is supplied along the opposite electrode 25 as a platen opposite electrode 25 being kept at a constant gap with respect to the ejection point 40 while being in contact with the surface of the opposite electrode 25.
  • the opposite electrode 25 is always applied with a bias voltage at a ground level or at a polarity opposite to that of the toner particle in the ink 3, and the recording sheet of paper 26 supplied on the opposite electrode 25 is always charged to a potential identical with that for the opposite electrode 25.
  • Fig. 11 shows a driving circuit system for driving the electrophoretic electrode 20 and a plurality of ejection electrodes 7.
  • a control circuit 70 controls an electrophoretic electrode driving circuit 72 and an ejection electrode driving circuit 73 based on printing data 200.
  • the electrophoretic electrode driving circuit 72 supplies a bias voltage to the electrophoretic electrode 20 during driving.
  • the bias voltage has a polarity identical with that of the charging polarity of the toner particles in the ink 3, by which the toner particles are repelled by the electrophoretic electrode 20 and moved toward the orifice.
  • the ejection electrode driving circuit 73 applies a pulse voltage at a polarity identical with that of the bias voltage applied to the electrophoretic electrode 20 and higher than the voltage to the ejection electrode 7 in accordance with the printing data 200. Thus, a strong electric field is generated between the ejection electrode 7 and the opposite electrode 25 in Fig. 10.
  • a bias voltage with a polarity identical with that of the toner particles in the ink 3 at such a level as not ejecting the ink 3 from the ejection point 40 is applied to the electrophoretic electrode 20 from the electrophoretic electrode driving circuit 72, and then the ink 3 in the chamber 4 is charged to the identical potential with the electrophoretic electrode 20. Further, toner particles in the ink 3 in the chamber 4 are circulated while moving so that they are collected to the ejection point 40 by the electric field between the ink 3 and the opposite electrode 25.
  • a pulse voltage of a polarity identical with that of the toner particles in the ink 3 (for example, +1200 V) is applied to the ejection electrode 7 surrounding the ejection point 40 corresponding to desired printing is applied from the ejection electrode driving circuit 73 to generate a strong electric field between the ejection electrode 7 and the opposite electrode 15.
  • An electrostatic force exerts by the electric field on the toner particles in the ink 3 on the ejection point 40 and, when the electrostatic force of the toner particles overcomes the surface tension of the meniscus 50 on the ejection point 40, an ink droplet 60 containing the toner particles on the ejection point 40 is ejected to the opposite electrode 25 to conduct printing on the recording sheet of paper 26.
  • Dots are formed in the form of depositing droplets of the toner particles on the recording sheet of paper 26, and toner particles deposited as droplets by a fixing mechanism of a heat roller or the like not illustrated are fixed on the recording sheet of paper 26.
  • the ink jet printing head 100 of the embodiment according to the present invention has the protrusion member 6 extending from the electrophoretic electrode 20 in the ink chamber 4 of the base plate 5 to the orifice 1, and the top end of the convex portion 6a penetrates the orifice 1 and protrudes to the opposite electrode. Accordingly, the ink droplet of the ink 3 (Fig. 10) always flies from the top end of the protrusion member 6 in the orifice 1 and the flying direction is stabilized. Further, since the top end of the convex portion 6a of the protrusion member 6 protrudes penetrating the orifice 1, the ink meniscus from retracting into the orifice 1 to form a concave portion after the flying of the ink droplet.
  • the protrusion member 6 extends from the electrophoretic electrode 20 toward the orifice 1, when the bias voltage is applied to the electrophoretic electrode 20, the toner particles in the chamber 4 can be moved along the protrusion member 6 to the orifice 1, and the concentration of the toner particles to the orifice 1 can be improved. That is, the protrusion member 6 serves as a guide for moving the toner particles from the chamber 4 toward the orifice 1.
  • the electrophoretic electrodes 20 are connected in common with the two protrusion members 6, a plurality of the ejection electrodes 7 are disposed individually to a plurality of orifices 1 respectively, and driven individually by the ejection electrode driving circuit 73 in Fig. 11.
  • the electrophoretic electrode 20 may also be bisected corresponding to the two orifice groups in the direction X shown in Fig. 4, and the electrophoretic electrode driving circuit 72 in Fig. 11 may drive the thus bisected electrophoretic electrodes individually. Further, the ejection electrode 7 may be grouped and the ejection electrode driving circuit 73 in Fig. 11 may drive each of groups individually.
  • a plurality of ejection electrodes 7 may be formed also as an inner layer circuit of the orifice plate 2.

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  • Particle Formation And Scattering Control In Inkjet Printers (AREA)
EP97118084A 1996-10-17 1997-10-17 Imprimante et tête électrostatique à jet d'encre Withdrawn EP0836943A3 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP27451396A JP2826535B2 (ja) 1996-10-17 1996-10-17 静電式インクジェットプリントヘッド
JP274513/96 1996-10-17

Publications (2)

Publication Number Publication Date
EP0836943A2 true EP0836943A2 (fr) 1998-04-22
EP0836943A3 EP0836943A3 (fr) 1999-05-26

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Family Applications (1)

Application Number Title Priority Date Filing Date
EP97118084A Withdrawn EP0836943A3 (fr) 1996-10-17 1997-10-17 Imprimante et tête électrostatique à jet d'encre

Country Status (2)

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EP (1) EP0836943A3 (fr)
JP (1) JP2826535B2 (fr)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0933214A2 (fr) * 1998-01-30 1999-08-04 H. Bollmann Manufacturers Ltd. Procédé et dispositif pour diriger de l'encre vers un substrat
EP1386739A2 (fr) * 2002-07-30 2004-02-04 Fuji Photo Film Co., Ltd. Tête jet d'encre électrostatique
US9291927B2 (en) 2011-09-09 2016-03-22 Hewlett-Packard Indigo B.V. Method and apparatus for concentrating an ink for an electrostatic printing process

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS58151257A (ja) * 1982-03-05 1983-09-08 Ricoh Co Ltd インクジエツト記録装置
JPS6287355A (ja) * 1985-10-15 1987-04-21 Olympus Optical Co Ltd マルチ素子インクジエツトプリンタ−
JPH01110964A (ja) * 1987-10-26 1989-04-27 Ricoh Co Ltd 静電型インクジェット記録装置
EP0703081A2 (fr) * 1994-09-22 1996-03-27 Kabushiki Kaisha Toshiba Appareil d'impression à jet d'encre à compression et éjection contrÔlées de colorants dans l'encre liquide

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS58151257A (ja) * 1982-03-05 1983-09-08 Ricoh Co Ltd インクジエツト記録装置
JPS6287355A (ja) * 1985-10-15 1987-04-21 Olympus Optical Co Ltd マルチ素子インクジエツトプリンタ−
JPH01110964A (ja) * 1987-10-26 1989-04-27 Ricoh Co Ltd 静電型インクジェット記録装置
EP0703081A2 (fr) * 1994-09-22 1996-03-27 Kabushiki Kaisha Toshiba Appareil d'impression à jet d'encre à compression et éjection contrÔlées de colorants dans l'encre liquide

Non-Patent Citations (2)

* Cited by examiner, † Cited by third party
Title
PATENT ABSTRACTS OF JAPAN vol. 007, no. 271 (M-260), 3 December 1983 & JP 58 151257 A (RICOH KK), 8 September 1983 *
PATENT ABSTRACTS OF JAPAN vol. 013, no. 334 (M-855), 27 July 1989 & JP 01 110964 A (RICOH CO LTD), 27 April 1989 *

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0933214A2 (fr) * 1998-01-30 1999-08-04 H. Bollmann Manufacturers Ltd. Procédé et dispositif pour diriger de l'encre vers un substrat
EP0933214A3 (fr) * 1998-01-30 2000-04-12 H. Bollmann Manufacturers Ltd. Procédé et dispositif pour diriger de l'encre vers un substrat
EP1386739A2 (fr) * 2002-07-30 2004-02-04 Fuji Photo Film Co., Ltd. Tête jet d'encre électrostatique
EP1386739A3 (fr) * 2002-07-30 2004-04-21 Fuji Photo Film Co., Ltd. Tête jet d'encre électrostatique
US6908177B2 (en) 2002-07-30 2005-06-21 Fuji Photo Film Co., Ltd. Electrostatic ejection type ink jet head
CN100391739C (zh) * 2002-07-30 2008-06-04 富士胶片株式会社 静电吐出型喷墨头
US9291927B2 (en) 2011-09-09 2016-03-22 Hewlett-Packard Indigo B.V. Method and apparatus for concentrating an ink for an electrostatic printing process

Also Published As

Publication number Publication date
JP2826535B2 (ja) 1998-11-18
EP0836943A3 (fr) 1999-05-26
JPH10119289A (ja) 1998-05-12

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