EP0510680A2 - Elektrofotografisches Druckgerät mit einem endlosen Band für primäre und sekundäre Übertragung - Google Patents

Elektrofotografisches Druckgerät mit einem endlosen Band für primäre und sekundäre Übertragung Download PDF

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Publication number
EP0510680A2
EP0510680A2 EP92107046A EP92107046A EP0510680A2 EP 0510680 A2 EP0510680 A2 EP 0510680A2 EP 92107046 A EP92107046 A EP 92107046A EP 92107046 A EP92107046 A EP 92107046A EP 0510680 A2 EP0510680 A2 EP 0510680A2
Authority
EP
European Patent Office
Prior art keywords
endless belt
printing apparatus
electrophotographic printing
transfer
roller
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Withdrawn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
EP92107046A
Other languages
English (en)
French (fr)
Other versions
EP0510680A3 (en
Inventor
Kazumi c/o NEC Corporation Aoyama
Takeshi c/o NEC Corporation Nakaoka
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
Priority claimed from JP9592991A external-priority patent/JPH04326384A/ja
Priority claimed from JP13641191A external-priority patent/JPH04360179A/ja
Priority claimed from JP13641091A external-priority patent/JPH04360178A/ja
Application filed by NEC Corp filed Critical NEC Corp
Publication of EP0510680A2 publication Critical patent/EP0510680A2/de
Publication of EP0510680A3 publication Critical patent/EP0510680A3/en
Withdrawn legal-status Critical Current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
    • G03G15/1605—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 using at least one intermediate support

Definitions

  • the present invention relates to an electrophotographic printing apparatus which transfers a toner image formed on a surface of a photosensitive drum to a sheet of paper by means of an endless belt.
  • a conventional electrophotographic printing apparatus performs a primary transfer of a toner image from a surface of a photosensitive drum to an endless belt by utilizing the cohesive force of the endless belt surface.
  • the endless belt and a sheet of paper are fed between a pressing roller and a heating roller, thereby simultaneously performing a secondary transfer of the toner image from the endless belt surface to the sheet and fixing of the image on the sheet. Therefore, the endless belt is required to have mutually conflicting properties, i.e. cohesiveness for the primary transfer and releaseability for the secondary transfer.
  • An object of the present invention is to provide an electrophotographic printing apparatus capable of transferring a toner image from a surface of a photosensitive drum to a sheet of paper without using a cohesive endless belt.
  • Another object of the invention is to provide an electronic photoprinting apparatus free from the offset phenomenon.
  • an electrophotographic printing apparatus having image forming means for forming a toner image having a first polarity on a photosensitive member; an endless belt having releaseability and movable relative to said photosensitive member while holding its front surface opposite to a surface of said photosensitive member; first transfer means provided on a position at a rear surface of said endless belt opposite to said photosensitive member for transferring said toner image onto said front surface of said endless belt by generating an electric charge having a second polarity reverse to said first polarity; and second transfer means for pressing a sheet of paper carried on said front surface of said endless belt together with said endless belt and thereby transferring said toner image onto said sheet of paper.
  • FIG. 1 is a schematic diagram showing a first embodiment of the present invention.
  • FIG. 2 is a schematic diagram showing a second embodiment of the present invention.
  • FIG. 3 is a schematic diagram showing a third embodiment of the present invention.
  • FIG. 4 is a schematic diagram showing a fourth embodiment of the present invention.
  • FIG. 5 is a perspective view showing a drive mechanism for a transfer roller shown in FIG. 4.
  • FIG. 6 is a schematic diagram showing a fifth embodiment of the present invention.
  • FIG. 7 is a schematic diagram showing a sixth embodiment of the present invention.
  • an corona charger 1 uniformly charges the surface of the photosensitive drum 4.
  • an exposing unit 2 forms an electrostatic latent image on the drum 4.
  • the developing unit 3 visualizes the latent image, formed on the drum 4 by the exposing unit 2, by adhering negatively electrified toner onto the latent image.
  • An endless belt 7 is made of polyimide, with its surface smoothed as a mirror and having releaseability, i.e., when the toner is attached, the toner is easy to release.
  • the endless belt 7 faces the photosensitive drum 4 and is applied tension by a belt guide 6, a belt drive roller 10 and a heating roller 8.
  • the belt 7 is driven to rotate by the belt drive roller 10 in the direction of an arrow 17 at the same speed as a peripheral speed of the photosensitive drum 4.
  • the toner image 14 on the endless belt 7 is simultaneously subjected to heat and press by the heating roller 8, made of an elastic material, and the pressure roller 11 including a built-in halogen lamp 9.
  • the heating roller 8 made of an elastic material
  • the pressure roller 11 including a built-in halogen lamp 9.
  • a secondary transfer and fixing of the toner image onto the sheet 12 are accomplished at the same time.
  • the sheet 12 is to be released from the endless belt 7, no toner remains on the endless belt 7 because of its releaseability. Therefore, the toner image 14 having undergone the second transfer and fixing onto the sheet 12 is free from trouble, such as partial image loss.
  • a second preferred embodiment of the present invention includes a transfer roller 26 capable of forming an electric field for the primary transfer of toner from the photosensitive drum 4 to the endless belt 7, and a heating element 29 far the secondary transfer and fixing of the toner from the endless belt 7 onto the sheet 12.
  • the electrified toner image 13 on the photosensitive drum 4 undergoes the primary transfer onto the endless belt 7 at a position where the belt 7 and the photosensitive drum 4 are in contact with each other by the formation of an electric field caused by applying a voltage to the transfer roller 26.
  • a toner image 34 transferred onto the endless belt 7 undergoes the simultaneous secondary transfer and fixing onto the sheet 12 at a position where the pressure roller 11 and the endless belt 7 face to each other.
  • the heating element 29 is used as the heat source whose heat is transmitted via the endless belt 7. Thermal efficiency is increased by keeping the heating element 29 in contact with the endless belt 7.
  • a brush transfer unit which is caused to generate an electric charge by applying a voltage to the brush may as well be used as the primary transfer unit.
  • a heating roller consisting of a heating element formed in a tubular or cylindrical shape can be used as the secondary transfer/fixing unit.
  • an corona charger 1 uniformly charges the surface of the photosensitive drum 4.
  • an exposing unit 2 forms an electrostatic latent image on the drum 4.
  • the developing unit 3 visualizes the latent image, formed on the drum 4 by the exposing unit 2, by adhering negatively electrified toner onto the latent image.
  • a transfer roller 46 transfers the toner image on the drum 4 onto a readily releaseable endless belt 27, made of polyimide, by an electrostatic force.
  • the toner image is attracted to the endless belt 27 by applying a voltage V to the transfer roller 46 to generate a positive charge having a polarity reverse to the toner image on the drum 4.
  • the transfer roller 46 is rotated by a drive motor 45.
  • the endless belt 27 has perforated edges for engaging sprockets 42 formed around the edges of the transfer roller 46.
  • the belt 27 is driven by the transfer roller 46 to carry a toner image 34 to a secondary transfer and fixing section.
  • a sheet of paper 12 is passed between a pressure roller 11 and the belt 27 whose rear surface is located with a heat roller 8.
  • the heating roller 8 has a built-in halogen lamp 9 as the heat source. Because of pressure and heat, the unfixed toner image 34 on the endless belt 27 is simultaneously transferred and fixed onto the sheet 12 by thermocompression fixing.
  • carrying means for the endless belt 27 is provided around the primary transfer roller 46, whose driving force drives the endless belt 27. Therefore, no other carrying means is needed for the endless belt 27, and this feature contributes to savings in space, the number of required parts and cost.
  • the fourth preferred embodiment of the invention has a configuration in which the driving force for the transfer roller 46 is derived from the rotational driving force of the photosensitive drum 4.
  • the configuration is identical with that of the third embodiment in all other respects.
  • a gear 44 provided at one end of the transfer roller 46 is engaged with another gear 43 provided on the photosensitive drum 4.
  • This configuration enables the transfer roller 46 to be rotated by the driving force of the photosensitive drum 4.
  • the endless belt 27 is driven by the sprockets 42 provided on the transfer roller 46 to carry the toner image 34 to the secondary transfer and fixing section.
  • the feed speed of the endless belt 27 can be stably synchronized with the peripheral speec of the photosensitive drum 4.
  • a beat roller 8' is used as the secondary transfer and fixing means, and sprockets 47 are provided at its both ends.
  • the endless belt 27 is driven by the driving force of the heat roller 8' via the sprockets 47.
  • the endless belt 27 has perforated edges engaged with the sprockets 47 formed around the edges of the heat roller 8' which is rotated by a motor 48.
  • the endless belt 27 is driven by the rotation of the heat roller 8' to carry the toner image 34 to the secondary transfer and fixing section.
  • the paper sheet 12 is passed between the pressure roller 11 and the heating roller 8' wound with the belt 27 and having the built-in halogen lamp 9 as the heat source.
  • the toner image 34 on the surface of the endless belt 27 is simultaneously transferred and fixed onto the sheet 12 by thermocompression fixing.
  • the tension of the endless belt 27 is adjusted with an adjusting roller 49 provided downstream of the heat roller 8' with respect to the moving direction of the belt 27.
  • the configuration is identical with that of the fifth embodiment in all other respects.
  • the present invention provides the benefit of achieving adequate transfers in the primary transfer and secondary transfer processes, resulting in reducing faulty images on the sheet, such as partial loss or the lack of vividness. This is because the endless belt has releaseability from the toner and the primary transfer of the image on the photosensitive member onto the endless belt is carried out by electrostatic force.
  • the endless belt is readily releaseable, there is provided the additional benefit in reducing such troubles as that the sheet adheres to the endless belt in the secondary transfer/fixing section or the image remaining on the endless belt is to be printed on the next sheet in the next secondary transfer/fixing process.

Landscapes

  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Electrostatic Charge, Transfer And Separation In Electrography (AREA)
EP19920107046 1991-04-26 1992-04-24 Electrophotographic printing apparatus having an endless belt for primary and secondary transfer Withdrawn EP0510680A3 (en)

Applications Claiming Priority (6)

Application Number Priority Date Filing Date Title
JP95929/91 1991-04-26
JP9592991A JPH04326384A (ja) 1991-04-26 1991-04-26 電子写真式印刷装置
JP136411/91 1991-06-07
JP13641191A JPH04360179A (ja) 1991-06-07 1991-06-07 電子写真式印刷装置
JP13641091A JPH04360178A (ja) 1991-06-07 1991-06-07 電子写真式印刷装置
JP136410/91 1991-06-07

Publications (2)

Publication Number Publication Date
EP0510680A2 true EP0510680A2 (de) 1992-10-28
EP0510680A3 EP0510680A3 (en) 1993-04-21

Family

ID=27307949

Family Applications (1)

Application Number Title Priority Date Filing Date
EP19920107046 Withdrawn EP0510680A3 (en) 1991-04-26 1992-04-24 Electrophotographic printing apparatus having an endless belt for primary and secondary transfer

Country Status (1)

Country Link
EP (1) EP0510680A3 (de)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0552745A2 (de) * 1992-01-21 1993-07-28 Sharp Kabushiki Kaisha Elektrophotographisches Druckgerät
EP0775948A1 (de) * 1995-11-24 1997-05-28 Xeikon Nv Mehrfarben elektrostatographischer Drucker mit einem Umlauf

Citations (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3128402A1 (de) * 1980-07-21 1982-04-15 Konishiroku Photo Industry Co., Ltd., Tokyo Bildwiedergabevorrichtung
US4341455A (en) * 1979-11-13 1982-07-27 Burroughs Corporation Conducting toner transfer apparatus
JPS592068A (ja) * 1982-06-29 1984-01-07 Fujitsu Ltd トナ−像転写装置
JPS5950474A (ja) * 1982-09-17 1984-03-23 Konishiroku Photo Ind Co Ltd 記録装置
JPS59131958A (ja) * 1983-01-19 1984-07-28 Fujitsu Ltd 記録装置
JPS63223678A (ja) * 1987-03-13 1988-09-19 Canon Inc 画像形成装置
JPH02105168A (ja) * 1988-10-14 1990-04-17 Fuji Xerox Co Ltd 画像形成装置の駆動機構
JPH02108072A (ja) * 1988-10-18 1990-04-19 Fujitsu Ltd カラー記録装置
EP0373704A1 (de) * 1988-12-15 1990-06-20 Océ-Nederland B.V. Verfahren und Gerät zur Herstellung eines mehrfarbigen Bildes

Patent Citations (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4341455A (en) * 1979-11-13 1982-07-27 Burroughs Corporation Conducting toner transfer apparatus
DE3128402A1 (de) * 1980-07-21 1982-04-15 Konishiroku Photo Industry Co., Ltd., Tokyo Bildwiedergabevorrichtung
JPS592068A (ja) * 1982-06-29 1984-01-07 Fujitsu Ltd トナ−像転写装置
JPS5950474A (ja) * 1982-09-17 1984-03-23 Konishiroku Photo Ind Co Ltd 記録装置
JPS59131958A (ja) * 1983-01-19 1984-07-28 Fujitsu Ltd 記録装置
JPS63223678A (ja) * 1987-03-13 1988-09-19 Canon Inc 画像形成装置
JPH02105168A (ja) * 1988-10-14 1990-04-17 Fuji Xerox Co Ltd 画像形成装置の駆動機構
JPH02108072A (ja) * 1988-10-18 1990-04-19 Fujitsu Ltd カラー記録装置
EP0373704A1 (de) * 1988-12-15 1990-06-20 Océ-Nederland B.V. Verfahren und Gerät zur Herstellung eines mehrfarbigen Bildes

Non-Patent Citations (6)

* Cited by examiner, † Cited by third party
Title
PATENT ABSTRACTS OF JAPAN vol. 13, no. 19 (P-814)18 January 1989 & JP-A-63 223 678 ( CANON K.K. ) 19 September 1988 *
PATENT ABSTRACTS OF JAPAN vol. 14, no. 321 (P-1074)10 July 1990 & JP-A-02 105 168 ( FUJI XEROX ) 17 April 1990 *
PATENT ABSTRACTS OF JAPAN vol. 14, no. 325 (P-1075)12 July 1990 & JP-A-02 108 072 ( FUJITSU ) 19 April 1990 *
PATENT ABSTRACTS OF JAPAN vol. 8, no. 153 (P-287)17 July 1984 & JP-A-59 050 474 ( KONISHIROKU SHASHIN KOGYO K.K. ) 23 March 1984 *
PATENT ABSTRACTS OF JAPAN vol. 8, no. 259 (P-317)(1696) 28 November 1984 & JP-A-59 131 958 ( FUJITSU K.K. ) *
PATENT ABSTRACTS OF JAPAN vol. 8, no. 86 (P-269)19 April 1984 & JP-A-59 002 068 ( FUJITSU K.K. ) 7 January 1984 *

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0552745A2 (de) * 1992-01-21 1993-07-28 Sharp Kabushiki Kaisha Elektrophotographisches Druckgerät
EP0552745A3 (en) * 1992-01-21 1993-10-27 Sharp Kk Electrophotographic printing machine
EP0775948A1 (de) * 1995-11-24 1997-05-28 Xeikon Nv Mehrfarben elektrostatographischer Drucker mit einem Umlauf

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Publication number Publication date
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