EP0672965A1 - Walze zur Herstellung eines Filmes in der Flüssigtoner Elektrophotographie - Google Patents

Walze zur Herstellung eines Filmes in der Flüssigtoner Elektrophotographie Download PDF

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Publication number
EP0672965A1
EP0672965A1 EP95301249A EP95301249A EP0672965A1 EP 0672965 A1 EP0672965 A1 EP 0672965A1 EP 95301249 A EP95301249 A EP 95301249A EP 95301249 A EP95301249 A EP 95301249A EP 0672965 A1 EP0672965 A1 EP 0672965A1
Authority
EP
European Patent Office
Prior art keywords
film
forming roller
roller
photoconductor surface
toner
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Withdrawn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
EP95301249A
Other languages
English (en)
French (fr)
Inventor
C.S. Chan
John A. Thompson
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.)
HP Inc
Original Assignee
Hewlett Packard Co
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 Hewlett Packard Co filed Critical Hewlett Packard Co
Publication of EP0672965A1 publication Critical patent/EP0672965A1/de
Withdrawn legal-status Critical Current

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Classifications

    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
    • G03G15/00—Apparatus for electrographic processes using a charge pattern
    • G03G15/14—Apparatus for electrographic processes using a charge pattern for transferring a pattern to a second base
    • G03G15/16—Apparatus for electrographic processes using a charge pattern for transferring a pattern to a second base of a toner pattern, e.g. a powder pattern, e.g. magnetic transfer
    • G03G15/169—Apparatus for electrographic processes using a charge pattern for transferring a pattern to a second base of a toner pattern, e.g. a powder pattern, e.g. magnetic transfer with means for preconditioning the toner image before the transfer
    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
    • G03G15/00—Apparatus for electrographic processes using a charge pattern
    • G03G15/06—Apparatus for electrographic processes using a charge pattern for developing
    • G03G15/10—Apparatus for electrographic processes using a charge pattern for developing using a liquid developer
    • G03G15/11—Removing excess liquid developer, e.g. by heat

Definitions

  • This invention relates generally to image transfer technology, and more specifically to electrophotography.
  • the invention is a soft film-forming roller which improves image integrity in a liquid toner electrophotographic apparatus and process.
  • a latent image is created on the surface of an insulating, photo-conducting material by selectively exposing areas of the surface to light. A difference in electrostatic charge density is created between the areas on the surface exposed and unexposed to light.
  • the visible image is developed by electrostatic toners containing pigment components dispersed in an insulating carrier liquid. The toners are selectively attracted to the photoconductor surface either exposed or unexposed to light, depending on the relative electrostatic charges of the photoconductor surface, development electrode and the toner.
  • the photoconductor may be either positively or negatively charged, and the toner system similarly may contain negatively or positively charged particles.
  • the preferred embodiment is that the photoconductor and toner have the same polarity, but different levels of charge.
  • a sheet of paper or an intermediate transfer medium is given an electrostatic charge opposite that of the toner and passed close to the photo-conductor surface, pulling the toner from the photoconductor surface onto the paper or the intermediate medium still in the pattern of the image developed from the photoconductor surface.
  • a set of fuser rollers melts and fixes the toner in the paper, subsequent to direct transfer or indirect transfer when using an intermediate transfer medium, producing the printed image.
  • liquid toners with pigment components and thermoplastic components dispersed in a liquid carrier medium, usually aliphatic hydrocarbon liquids.
  • the liquid toners contain latex-like components, or "film-forming" components, as well as charge-accepting components so that the liquid toner may also be electrically biased.
  • the basic printing colors - yellow, magenta, cyan and black may be applied sequentially to a photoconductor surface, and from there to a sheet of paper or intermediate medium to produce a multi-colored image.
  • film-forming toners may be used with this invention.
  • liquid toners there is a need to remove the liquid carrier medium from the photoconductor surface after the toner has been applied to it. This way, the photoconductor surface will not transfer the liquid carrier to the paper or to the intermediate medium in the image transfer step(s). Also, this way the liquid carrier may be recovered for recycle and reuse in the developer system, providing economy in terms of printing supplies, and eliminating environmental and health concerns from disposal of excess liquid carrier medium.
  • U.S. Patent No. 4,325,627 discloses an arcuate field electrode positioned between a squeegee roller and a transferring station where the freshly developed image is transferred to a carrier sheet.
  • the field electrode is biased to a potential of a sign opposite to the charge of the toner particles.
  • the invention is a relatively soft film-forming roller mounted to be in rotational contact with the photoconductor surface downstream of the developer station from the perspective of travel of the photoconductor surface in an electro-photographic apparatus.
  • the film-forming roller can be conductive.
  • the film-forming roller of the preferred embodiment is conductive and is electrically biased at between about 500 - 1000(+) V when used with a positive charging photoconductor.
  • the film-forming roller is internally heated to a surface temperature of approximately 40°C, and applied to the photoconductor surface at a pressure of approximately 1/2 Ib./linear inch.
  • the film-forming roller acts to dry the latent image by evaporating the liquid toner carrier medium, and by increasing the temperature of the toner film. The combined charge, heat and pressure of the film-forming roller will accelerate film forming of the latent image as it passes through the roller.
  • the film-forming roller is utilized in a liquid toner, laser printer with an intermediate, indirect image transfer system.
  • Fig. 1 is a schematic side view of one embodiment of the present invention, showing the film forming roller and the optional indirect transfer system in a liquid electro-photographic system.
  • the photoconductor is an organic photoconductor (OPC) which rotates in the clockwise direction as indicated by the arrow.
  • OPC organic photoconductor
  • the OPC in the preferred embodiment is of the positive charging type, and has the following components or subsystems placed around its circumference in the order of its clockwise rotation:
  • the OPC has a special film-forming roller (FR) mounted to be in rotational contact with the OPC at approximately the eight o'clock position.
  • the OPC has an optional indirect transferring system, with first and second transfer rollers T1 and T2, respectively, at approximately the twelve o'clock position.
  • the operations of the erase lamp, charging device and laser exposing device are conventional, and therefore will not be described in detail here.
  • the developer may be of conventional construction, but is preferably a liquid toner bath with an open top surface in close proximity (approximately 50-75 microns, or .002 - .003 inches) to the outer bottom of the OPC surface for applying a thin film of toner to the surface.
  • the toner bath is charged to an intermediate level, between the level of the charged and discharged areas of the photoconductor surface, but of the same sign.
  • a positively-charged developer roller Slightly downstream of the liquid toner bath, in the direction of movement of the OPC surface, is a positively-charged developer roller, the outer surface of which is also in close proximity (approximately 50-75 microns, or .002 - .003 inches) to the outer bottom of the OPC surface.
  • the developer roller rotates so that its outer surface moves in the opposite direction of movement of the OPC surface.
  • the rigidizing squeegee roller may also be electrically biased and rotates so that its outer surface moves in the same direction, and at the same speed, as the OPC surface. Therefore, there is no relative motion between the squeegee roller and the OPC surface. This way, the rigidizing squeegee roller removes residual toner liquid from the OPC surface, resulting in a dryer image.
  • the latent image is already formed on the surface of the OPC by the time it exits the liquid developer station. However, at this point the image is semi-wet, with a solids content of approximately 60 - 75%, and it has formed no film yet. Before such an image may be effectively transferred, it must first be further dried and film-formed to improve image integrity. There are two ways to accelerate the film-forming event: one, dry the image by evaporating the solvent or carrier material for the toner; and, two, increase the temperature of the toner film.
  • a special film-forming roller (FR) according to this invention at approximately the eight O'clock position on the OPC drum accelerates the film forming in both ways.
  • the film-forming roller (FR) is relatively soft or of semi-rigid construction, with a durometer index of about 40 shore A.
  • the film-forming roller is here conductive, having an electrical resistivity of about 1E6 ohm-cm, and is electrically biased at between about 500 - 1000 (+)V when used with positive-charging photoconductors and positively-charged liquid toners, however, it should be noted that the conductivity and electrical biasing of the film-forming roller is related to the type of toner used and may not be necessary.
  • the film-forming roller is internally heated to a surface temperature of approximately 40°C, and applied to the photoconductor surface at a pressure of approximately 1/2 lb/linear inch. The combined charge, heat and pressure of the film-forming roller will accelerate film forming of the latent image on the photoconductor surface as it passes through the roller.
  • the film-forming roller (FR) is utilized in a liquid toner, laser printer with an intermediate, indirect image transfer system.
  • a first transfer roller (T1) which is in contact with the photoconductor surface downstream of the film-forming roller.
  • the first transfer roller is of 2-ply construction, with the inner layer being pliant silicon rubber and the outer layer being fluoro silicon material.
  • a preferred fluorosilicon material is DC93004, available from Dow Chemical Co.
  • the fluorosilicon material has a durometer index of between about 40 - 70 and a higher adhesion force with respect to the toner film than the adhesion force between the toner and the photoconductor surface.
  • the first transfer roller is internally heated to a surface temperature of between about 45° - 80°C, preferably about 50°C, and applied to the photoconductor surface at a pressure of approximately 10 lb/linear inch.
  • a surface temperature of between about 45° - 80°C, preferably about 50°C
  • the transfer rollers T1 and T2 may also be electrically charged to further enhance the image integrity.
  • the first transfer roller (T1) is in contact also with a second transfer roller (T2).
  • the second transfer roller (T2) is a hard roller of either steel or aluminum construction. It is internally heated to a surface temperature of between about 100° - 150°C, preferably about 150°C when high cycle speeds are desired, and applied to the first transfer roller surface at a pressure of 15 - 20 lb/linear inch.
  • the printing media, paper or transparency material is transported between the first and second transfer rollers. When the transferred image on the first transfer roller is rotated to the position where the first transfer roller contacts the second transfer roller, the image is pressed against the paper passing through the rollers.
  • a source of heat like a heat lamp, for example, may also be made available between the developing station and the indirect transfer system.

Landscapes

  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Wet Developing In Electrophotography (AREA)
  • Electrostatic Charge, Transfer And Separation In Electrography (AREA)
EP95301249A 1994-03-16 1995-02-27 Walze zur Herstellung eines Filmes in der Flüssigtoner Elektrophotographie Withdrawn EP0672965A1 (de)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US21490394A 1994-03-16 1994-03-16
US214903 1994-03-16

Publications (1)

Publication Number Publication Date
EP0672965A1 true EP0672965A1 (de) 1995-09-20

Family

ID=22800856

Family Applications (1)

Application Number Title Priority Date Filing Date
EP95301249A Withdrawn EP0672965A1 (de) 1994-03-16 1995-02-27 Walze zur Herstellung eines Filmes in der Flüssigtoner Elektrophotographie

Country Status (2)

Country Link
EP (1) EP0672965A1 (de)
JP (1) JPH07311503A (de)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5650253A (en) * 1995-09-29 1997-07-22 Minnesota Mining And Manufacturing Company Method and apparatus having improved image transfer characteristics for producing an image on a receptor medium such as a plain paper
US5916718A (en) * 1995-09-29 1999-06-29 Imation Corp. Method and apparatus for producing a multi-colored image in an electrophotographic system
WO2007001303A1 (en) * 2005-06-27 2007-01-04 Hewlett-Packard Development Company, L.P. Method and apparatus for reducing liquid content in electrostatic printing
WO2019074519A1 (en) 2017-10-13 2019-04-18 Hp Indigo B.V. LIQUID ELECTROPHOTOGRAPHIC PRINTING ON FABRICS

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6253051B1 (en) 1999-01-18 2001-06-26 Nec Corporation Wet-type image forming apparatus and method
JP2002254597A (ja) * 2001-03-06 2002-09-11 Toshiba Mach Co Ltd 印刷機のオフセット転写機構
WO2011025508A1 (en) * 2009-08-31 2011-03-03 Hewlett-Packard Development Company, L.P. Liquid marking agent development assemblies, hard imaging devices, and liquid marking agent hard imaging methods

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3689147A (en) * 1967-12-20 1972-09-05 Shigeru Suzuki Liquid-development type electrophotographic apparatus including paper drier means
US4286039A (en) * 1979-05-15 1981-08-25 Savin Corporation Method and apparatus for removing excess developing liquid from photoconductive surfaces
US5028964A (en) * 1989-02-06 1991-07-02 Spectrum Sciences B.V. Imaging system with rigidizer and intermediate transfer member
US5136334A (en) * 1991-05-17 1992-08-04 Hewlett-Packard Company Method and apparatus for preparing liquid tone for direct transfer to the media during electrophotographic printing

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3689147A (en) * 1967-12-20 1972-09-05 Shigeru Suzuki Liquid-development type electrophotographic apparatus including paper drier means
US4286039A (en) * 1979-05-15 1981-08-25 Savin Corporation Method and apparatus for removing excess developing liquid from photoconductive surfaces
US5028964A (en) * 1989-02-06 1991-07-02 Spectrum Sciences B.V. Imaging system with rigidizer and intermediate transfer member
US5136334A (en) * 1991-05-17 1992-08-04 Hewlett-Packard Company Method and apparatus for preparing liquid tone for direct transfer to the media during electrophotographic printing

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5650253A (en) * 1995-09-29 1997-07-22 Minnesota Mining And Manufacturing Company Method and apparatus having improved image transfer characteristics for producing an image on a receptor medium such as a plain paper
US5916718A (en) * 1995-09-29 1999-06-29 Imation Corp. Method and apparatus for producing a multi-colored image in an electrophotographic system
WO2007001303A1 (en) * 2005-06-27 2007-01-04 Hewlett-Packard Development Company, L.P. Method and apparatus for reducing liquid content in electrostatic printing
WO2019074519A1 (en) 2017-10-13 2019-04-18 Hp Indigo B.V. LIQUID ELECTROPHOTOGRAPHIC PRINTING ON FABRICS
CN111052000A (zh) * 2017-10-13 2020-04-21 惠普印迪格公司 织物上的液体电子照相打印
EP3619578A4 (de) * 2017-10-13 2020-12-23 HP Indigo B.V. Flüssiges elektrofotografisches drucken auf gewebe
US11487225B2 (en) 2017-10-13 2022-11-01 Hp Indigo B.V. Liquid electrophotography printing on fabrics

Also Published As

Publication number Publication date
JPH07311503A (ja) 1995-11-28

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