US3764207A - Electrophotographic process utilizing single charging means for effecting simultaneous functions of charging and facilitating toner image transfer - Google Patents

Electrophotographic process utilizing single charging means for effecting simultaneous functions of charging and facilitating toner image transfer Download PDF

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Publication number
US3764207A
US3764207A US00206034A US3764207DA US3764207A US 3764207 A US3764207 A US 3764207A US 00206034 A US00206034 A US 00206034A US 3764207D A US3764207D A US 3764207DA US 3764207 A US3764207 A US 3764207A
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United States
Prior art keywords
photoreceptor
toner
charging
image
toner image
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Expired - Lifetime
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US00206034A
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English (en)
Inventor
K Obuchi
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Fujifilm Holdings Corp
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Fuji Photo Film Co Ltd
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    • 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
    • G03G13/00—Electrographic processes using a charge pattern
    • G03G13/14—Transferring a pattern to a second base
    • G03G13/16—Transferring a pattern to a second base of a toner pattern, e.g. a powder pattern
    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
    • G03G13/00—Electrographic processes using a charge pattern
    • G03G13/22—Processes involving a combination of more than one step according to groups G03G13/02 - G03G13/20
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10S430/00—Radiation imagery chemistry: process, composition, or product thereof
    • Y10S430/001—Electric or magnetic imagery, e.g., xerography, electrography, magnetography, etc. Process, composition, or product
    • Y10S430/102—Electrically charging radiation-conductive surface

Definitions

  • ABSTRACT The electrophotographic duplication process comprising:
  • step (a) (1. charging said developed latent image and said photoreceptor with a charge of the same polarity as in step (a), thereby reversing the polarity of said toner and recharging said photoreceptor surface;
  • FIG. 1 A typical example of such conventional electrophotographic duplicating process is shown in FIG. 1.
  • a cylindrical photoreceptor I is first given an electrostatic charge by a charging corotron 2 of a polarity determined by the physical properties of the photoreceptor used while rotating in the direction of the arrow shown in FIG. 1.
  • the surface of photoreceptor is then subjected to exposure represented by 12 through an optical system not shown in the drawing.
  • An electrostatic latent image is formed in a known manner on the surface of photoreceptor by the exposure. This electrostatic image is developed when it passes developing device 3, and a transferable image corresponding to the electrostatic latent image is formed.
  • the image is formed by the application of a fine colored plastic powder known as a toner.
  • a fine colored plastic powder known as a toner.
  • known electrophotographic developing process such as cascade developing magnetic brush developing and the like are typically used.
  • the image formed on the surface of photoreceptor 1 is brought into intimate contact with a receiving material 4, which is conveyed at the same speed as the surface of photoreceptor l, and is transferred onto the surface of the receiving material 4, for example, by the known electrostatic transferring process, which involves providing the back surface of receiving material 4 with'an electrostatic charge opposite polarity to that of the electrostatic charge on the image-forming substance (e.g., the toner). This is accomplished by means of transferring corotron 5 disposed at the back surface of the transfer material facing to the photoreceptor I.
  • the process of the present invention can be carried out with less steps, and the construction of the electrophotographic duplicator can be remarkably simplified, as seen in FIG. 3.
  • the object of the present invention is to provide a process for and particularly an electrophotographic duplicating process employing a photoreceptor for repetitive use and accompanied by an image-transferring step, in which processing steps are reduced, the device to be used is more simple in its'construction, and can be manufactured in small sized device with lower costs, compared to conventional duplicating processes which have been put in practice or published heretofore.
  • FIG. 1 is a diagram illustrating a known electrophotographic duplicator.
  • FIG. 2 is a diagram illustrating an electrophotographic process according to the present invention.
  • FIG. 3 is a diagram illustrating an electrophotographic duplicator for effecting the process according to the present invention.
  • a photoreceptor ll (herein shown as a flat plate-like photoreceptor for convenience of illustration) is given a uniform electrostatic charge from a corotron 9.
  • the electrostatic charge given is shown as a positive charge a negative charge could also be used depending on the physical properties of the photoreceptor, as is known to the art.
  • FIG. is shown the state in which the abovementioned electrostatic latent image is developed by a known electrophotographic developing process, and an image 13 is formed of a toner.
  • the toner image 13 has an electrostatic charge of a polarity opposite to that which is given to the photoreceptor 11.
  • the surface of the photoreceptor 11 on which toner image 13 is formed is charged with the same polarity as in case of the process shown in FIG. 2a from a corotron 9, in this embodiment a positive charge at this time the polarity of the toner which forms the image 13 is reversed, and simultaneously the portions of the photosensitive plate that lost their electric charge by exposure are recharged.
  • the portion of the photoreceptor covered by toner image 13 is also recharged through gaps which exist among the toner particles.
  • the residual electrostatic charge on this portion (under the toner 13) is more attenuated than in the state shown in FIG. 20 by dark decay of the photoreceptor.
  • the potential is high.
  • step 2d relates to uniformly charging the surface of the photoreceptor with reversing the toner image polarity, thereby preparing the toner image for the following transferring step 22.
  • the potential of the photoreceptor rises in proportion to the electrostatic charge given, the potential of the toner image portion and the nonimage portion must both rise, maintaining the potential difference that both portions had immediately before the process shown in FIG. 2d.
  • the saturation potential which is determined by the electrostatic charging condition, no significant difference exists between the potential toner image portion and the non-image portion of the photoreceptor at the completion of the electrostatic charging step.
  • a receiving material 4 is superposed on the surface of the photoreceptor, pressed from the back side by, for example, a grounded conductive roller 10, and an image 13 is transferred onto the surface of receiving material.
  • the residual toner image is then cleaned off the photoreceptor 11 while maintaining the latter in a dark place.
  • the photoreceptor being already uniformly charged due to the process shown in FIG. 2d, can be immediately returned to the step shown in FIG. 2d and processed repeatedly in the manner as described above.
  • the electrostatic latent image is formed by utilizing the charge given in the process step shown in FIG. 2d, and thus the light source for erasure 8 as shown in FIG. 1 is not needed at all.
  • FIG. 3 shows an example of a device in which the electrophotographic duplicating process according to the present invention can be repetitively effected using a cylindrical photoreceptor.
  • the cylindrical photoreceptor 1 is first given an electrostatic charge from coroton 9 while rotating in the direction of the arrow. Then, an exposure 12 is given to its surface through an optical system not shown in the drawing. The electrostatic latent image formed by exposure is developed when it passes through developing device 3, and a transferable image is thereby formed. Developing processes and developers heretofore used by the prior art in known electrophotographic duplicating processes may be employed.
  • the image is then reversed in polarity of electrostatic charge by means of corotron 9 and the photoreceptor 1 also is restored with the electrostatic charge which it lost by exposure.
  • the image is then brought into contact with the receiving material 4 conveyed at a speed corresponding to the surface speed of the photoreceptor I, pressed from the back by means of grounded conductive transfer roller 10 and transferred onto the surface of receiving material 4.
  • cleaning means 7 which may be a rotating brush, and the photoreceptor 1 is subjected again to the above-mentioned process starting from the exposure step.
  • cleaning means 7 which may be a rotating brush
  • the means for pressing the receiving material onto the surface of the photoreceptor in the transfer step it is not necessary to use a roller, and an element such as slider may also act in an excellent manner.
  • this roller or slider need not always'be conductive.
  • electrophotographic duplicating apparatus comprising a photoreceptor surface, charging means to charge said surface, exposing means to expose said charged surface, developing means to develop said charged surface and provide a toner image and toner image transfer means for transferring said toner image to a receiving material, the improvement wherein said toner transfer means is disposed immediately after said charging means, said charging means effecting the simultaneous functions of charging said photoreceptor and reversing the polarity of said toner image from an initial value, which initial value is opposite to the charge imparted by the charging means.
  • Electrophotographic duplication apparatus comprising:
  • means for charging the surface of an electrophotographic photoreceptor means for exposing the charged surface to form an electrostatically charged latent image thereon; means for developing said latent image with a toner having a charge opposite to that of said latent image; means for transferring the majority of said toner to a receiving layer to form a toner image; and means for removing residual toner from said photoreceptor; only said charging means being disposed between said developing means and said image transferring means so that prior to image transfer, the polarity of said toner is reversed and the surface of the photoreceptor is charged.

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  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Combination Of More Than One Step In Electrophotography (AREA)
  • Electrophotography Using Other Than Carlson'S Method (AREA)
  • Electrostatic Charge, Transfer And Separation In Electrography (AREA)
US00206034A 1970-12-10 1971-12-10 Electrophotographic process utilizing single charging means for effecting simultaneous functions of charging and facilitating toner image transfer Expired - Lifetime US3764207A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP45109878A JPS5023986B1 (enrdf_load_stackoverflow) 1970-12-10 1970-12-10

Publications (1)

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US3764207A true US3764207A (en) 1973-10-09

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US00206034A Expired - Lifetime US3764207A (en) 1970-12-10 1971-12-10 Electrophotographic process utilizing single charging means for effecting simultaneous functions of charging and facilitating toner image transfer

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US (1) US3764207A (enrdf_load_stackoverflow)
JP (1) JPS5023986B1 (enrdf_load_stackoverflow)
DE (1) DE2161428A1 (enrdf_load_stackoverflow)
GB (1) GB1364635A (enrdf_load_stackoverflow)
NL (1) NL7116977A (enrdf_load_stackoverflow)

Cited By (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3972611A (en) * 1970-03-18 1976-08-03 Canon Kabushiki Kaisha Apparatus for transferring images produced by liquid developer
US3994725A (en) * 1973-06-18 1976-11-30 Xerox Corporation Method for enhancing removal of background toner particles
US4172905A (en) * 1973-01-26 1979-10-30 The Commonwealth Of Australia Transferring xerographic images
US4297422A (en) * 1977-07-21 1981-10-27 Olympus Optical Company Limited Electrophotographic process for printing a plurality of copies
US4297423A (en) * 1977-11-30 1981-10-27 Olympus Optical Company Limited Electrophotographic process for multiple images
US4427755A (en) 1978-07-21 1984-01-24 Hitachi, Ltd. Method for transferring toner images in electrophotography
US4432631A (en) * 1976-12-15 1984-02-21 International Business Machines Corporation Photoconductor charging technique
US4746950A (en) * 1985-01-09 1988-05-24 Ricoh Company, Ltd. Color copier
US4959688A (en) * 1987-10-19 1990-09-25 Canon Kabushiki Kaisha Image forming apparatus having charging and discharging means
US5323215A (en) * 1991-04-10 1994-06-21 Tokyo Electric Co., Ltd. Charging members for charging a photosensitive body without removing used toner from the body
US5396314A (en) * 1991-12-19 1995-03-07 Mita Industrial Co., Ltd. Image forming apparatus having functional redundancy system

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS52121198U (enrdf_load_stackoverflow) * 1976-03-12 1977-09-14
US4175955A (en) * 1976-09-24 1979-11-27 Minolta Camera Kabushiki Kaisha Electrophotographic processes using a pre-exposure
JPS5381237A (en) * 1976-12-27 1978-07-18 Minolta Camera Co Ltd Photosensitivity control of photosensitive body

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2817765A (en) * 1956-01-03 1957-12-24 Haloid Co Xerographic method
US3041167A (en) * 1959-08-19 1962-06-26 Xerox Corp Xerographic process
US3368894A (en) * 1963-11-05 1968-02-13 Australia Res Lab Multiple copy printing method and apparatus

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2817765A (en) * 1956-01-03 1957-12-24 Haloid Co Xerographic method
US3041167A (en) * 1959-08-19 1962-06-26 Xerox Corp Xerographic process
US3368894A (en) * 1963-11-05 1968-02-13 Australia Res Lab Multiple copy printing method and apparatus

Cited By (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3972611A (en) * 1970-03-18 1976-08-03 Canon Kabushiki Kaisha Apparatus for transferring images produced by liquid developer
US4172905A (en) * 1973-01-26 1979-10-30 The Commonwealth Of Australia Transferring xerographic images
US3994725A (en) * 1973-06-18 1976-11-30 Xerox Corporation Method for enhancing removal of background toner particles
US4432631A (en) * 1976-12-15 1984-02-21 International Business Machines Corporation Photoconductor charging technique
US4297422A (en) * 1977-07-21 1981-10-27 Olympus Optical Company Limited Electrophotographic process for printing a plurality of copies
US4297423A (en) * 1977-11-30 1981-10-27 Olympus Optical Company Limited Electrophotographic process for multiple images
US4427755A (en) 1978-07-21 1984-01-24 Hitachi, Ltd. Method for transferring toner images in electrophotography
US4746950A (en) * 1985-01-09 1988-05-24 Ricoh Company, Ltd. Color copier
US4959688A (en) * 1987-10-19 1990-09-25 Canon Kabushiki Kaisha Image forming apparatus having charging and discharging means
US5323215A (en) * 1991-04-10 1994-06-21 Tokyo Electric Co., Ltd. Charging members for charging a photosensitive body without removing used toner from the body
US5396314A (en) * 1991-12-19 1995-03-07 Mita Industrial Co., Ltd. Image forming apparatus having functional redundancy system

Also Published As

Publication number Publication date
DE2161428A1 (de) 1972-08-31
GB1364635A (en) 1974-08-21
NL7116977A (enrdf_load_stackoverflow) 1972-06-13
JPS5023986B1 (enrdf_load_stackoverflow) 1975-08-12

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