US3697172A - Electrostatic photography - Google Patents

Electrostatic photography Download PDF

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Publication number
US3697172A
US3697172A US844536A US3697172DA US3697172A US 3697172 A US3697172 A US 3697172A US 844536 A US844536 A US 844536A US 3697172D A US3697172D A US 3697172DA US 3697172 A US3697172 A US 3697172A
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US
United States
Prior art keywords
photosensitive
photosensitive plate
plate
photoconductive
corona discharge
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.)
Expired - Lifetime
Application number
US844536A
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English (en)
Inventor
Wasaburo Ohta
Setsuo Soga
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.)
Ricoh Co Ltd
Original Assignee
Ricoh Co Ltd
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 Ricoh Co Ltd filed Critical Ricoh Co Ltd
Application granted granted Critical
Publication of US3697172A publication Critical patent/US3697172A/en
Anticipated expiration legal-status Critical
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    • 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
    • G03G13/04—Exposing, i.e. imagewise exposure by optically projecting the original image on a photoconductive recording material
    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
    • G03G5/00—Recording members for original recording by exposure, e.g. to light, to heat, to electrons; Manufacture thereof; Selection of materials therefor
    • G03G5/02—Charge-receiving layers
    • G03G5/04—Photoconductive layers; Charge-generation layers or charge-transporting layers; Additives therefor; Binders therefor
    • G03G5/043—Photoconductive layers characterised by having two or more layers or characterised by their composite structure
    • 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

  • the invention relates to an electrostatic photography method in which a photosensitive plate with-photoconductive layers on both sides of the supporting material is used.
  • the reverse side or the back side of the photosensitive plate is also charged up in the course of charging the right side of the photosensitive plate by corona discharge or the like, since the photoconductive layer in the reverse side has a high electric resistivity in the dark, even though a material of low electric resistivity is used for the supporting material.
  • The. photosensitive plate in accordance with this invention is characterized in that photoconductive layers are applied on both sides of its supporting material so that one end portion of each of both sides of the conductive supporting material is exposed.
  • the total area of the photosensitive plate cannot be used efficiently, since the conductive material is exposed at one end of the photosensitive plate.
  • the present invention is based on a principle completely different from that of the invention referred above, and its object is to use all the surfaces of the photosensitive plate effectively and to provide a method of electrostatic photography in which the nonimaged part of photosensitive paper is not smeared in the course of development.
  • a mixed layer of zinc oxide and a resin or an evaporated layer of selenium is used as a photoconductive sensitive paper for usual electrostatic photography and these photoconductive materials have a relatively high electric resistivity, say, up to more than .Q-cm in the dark while the electric resistivity drops down to 10 Q-cm or less when they are brought into the light, and they show a good conductivity for the discharge current in a corona discharge or the like.
  • the principle of this invention consists in utilizing such characteristics of photoconductive materials, and when an electric charge is applied on a photosensitive plate with photoconductive sensitive layer on both sides of its supporting material, the photosensitive layer on which the charge should not be applied, that is, the photosensitive layer on the reverse side is illuminated by light simultaneously in order to decrease the electric resistivity so that the layer becomes conductive to the discharge current and the barrier to the corona discharge is dissolved.
  • an efficient and proper charging process is conducted on the photoconductive sensitive layer on the side on which electrostatic latent images should be formed, and at the same time, it suppresses the charging on the reverse side of the photoconductive layer to an extremely low level.
  • FIG. 1 is an enlarged cross sectional view of a photosensitive plate which is used in the present invention
  • FIG. 2 is an enlarged cross sectional view of an embodiment in accordance with the invention.
  • FIG. 3 is an enlarged cross sectional view of another embodiment of the invention.
  • FIG. 1 is an embodiment of a photosensitive plate for the electrostatic photography which is used in the invention, and this photosensitive plate 1 is composed of a supporting plate 2 of a paper, a plastic, a metal, or the like with photoconductive sensitive layers 3 and 4 on both sides of the supporting plate.
  • photoconductive sensitive layers 3 and 4 those inorganic or organic photoconductive substances similarto those used in the ordinary electrostatic photography, such as selenium, zinc oxide, zinc sulphide, cadmium sulphide, etc. or N- vinyl carbazol, or mixtures of these substances with silicon resin, alkyd resin, vinyl resin, etc., may be used.
  • FIG. 2 shows an embodiment of a charging device used in the invention, comprising a corona discharge part 5, a high voltage power supply 6, a light source 7 for illumination and an electrode 8 for corona discharge which is almost transparent to light.
  • a transparent electrode the so-called NESA glass (trade name) can be used, which is a transparent glass with a NESA coating on it, or a transparent electrode of transparent glass or plastics coated with a thin layer of copper iodide or cadmium oxide on its surface by vacuum evaporation can also be used.
  • the thin layer 8a is grounded.
  • the above-mentioned photosensitive plate I placed on the transparent electrode 8 undergoes a corona discharge from the corona discharge part 5, and at the same time, a photosensitive layer 4 on the reverse side of the photosensitive plate 1 is exposed to light from below through the transparent electrode 8 by a light source for illumination. In this way, the electric resistivity of the photosensitive layer 4 which is in contact with the transparent electrode drops down, while the photoconductive sensitive layer 3 on the right side is charged up by the corona discharge.
  • the exposure light can be focused at a part where a corona discharge occurs.
  • FIG. 3 shows another embodiment of the charging device which is usable in the invention.
  • Corona "discharge parts 9 and 10 are provided according to the power supply 1 l, a light source 12 for illumination, and
  • the shield 13 for the corona discharge part 10 has an opening for the exposure light from the light source 12 to pass through it.
  • the shield 13 can be a transparent electrode such as of NESA glass mentioned above.
  • the object of this invention can also be achieved by the charging device in accordance with the double corona system.
  • the corona charging process can be conducted after the projection of light on the reverse side of photosensitive plate, or the corona discharge can be done first and the charge on the photosensitive layer on the reverse side can be dissipated through the projection of light only on the reverse side after the corona discharge, making the photosensitive layer conductive, so that 'the charge on the photosensitive layer on the reverse side is substantially diminished.
  • a copying on both sides of a photosensitive plate can be done efficiently and an excellent quality image can be obtained on both sides of the photosensitive plate with photoconductive sensitive layers on both sides of its supporting plate in the electrostatic photography.
  • a method of electrostatic photography comprising the steps of selecting a photosensitive plate having photoconductive sensitive layers on both sides of a supporting plate, uniformly illuminating one side of said photosensitive plate by overall non-image light exposure in order to decrease the electrical resistivity of said one side, charging the other side of said photosensitive plate by a corona discharge, and said illuminating step being conducted during said charging step. 7 2.
  • a method of electrostatic photography comprising the steps of selecting a photosensitive plate having photoconductive sensitive layers on both sides of a supporting plate, uniformly illuminating one side of said photosensitive plate by overall non-image light exposure in order to decrease the electrical resistivity of said one side, charging the other side of said photosensitive plate by a corona discharge, and said illuminating step being conducted before said charging step.

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  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Photoreceptors In Electrophotography (AREA)
US844536A 1968-09-09 1969-07-24 Electrostatic photography Expired - Lifetime US3697172A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP6449368 1968-09-09

Publications (1)

Publication Number Publication Date
US3697172A true US3697172A (en) 1972-10-10

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Application Number Title Priority Date Filing Date
US844536A Expired - Lifetime US3697172A (en) 1968-09-09 1969-07-24 Electrostatic photography

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US (1) US3697172A (nl)
DE (1) DE1939376A1 (nl)
FR (1) FR2017608A1 (nl)
GB (1) GB1288395A (nl)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3766428A (en) * 1972-07-24 1973-10-16 Westinghouse Electric Corp High resolution, high intensity cathode ray tube
US3789223A (en) * 1970-08-11 1974-01-29 Fuji Photo Film Co Ltd Charging method for relatively movable electrophotographic means and corona means
US4195991A (en) * 1977-10-21 1980-04-01 James River Graphics Inc. Electrographic recording method of applying an electric field opposite the charge retaining layer
US5116714A (en) * 1989-02-06 1992-05-26 Sony Corporation Image forming material with developer and photosensitive base on which an electrostatic latent image is formed

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2962375A (en) * 1956-05-02 1960-11-29 Haloid Xerox Inc Color xerography
US2963365A (en) * 1956-02-16 1960-12-06 Rca Corp Electrostatic printing
US3285740A (en) * 1961-10-25 1966-11-15 Gen Aniline & Film Corp Electrophotographic process
US3443936A (en) * 1964-08-20 1969-05-13 Agfa Gevaert Ag Process for the production of electrophotographic images
US3517995A (en) * 1967-10-02 1970-06-30 Xerox Corp Method and apparatus for increasing the efficiency of corona charging
US3561958A (en) * 1967-04-07 1971-02-09 Xerox Corp Inducing frost deformation imaging by electrolytic deposition

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2963365A (en) * 1956-02-16 1960-12-06 Rca Corp Electrostatic printing
US2962375A (en) * 1956-05-02 1960-11-29 Haloid Xerox Inc Color xerography
US3285740A (en) * 1961-10-25 1966-11-15 Gen Aniline & Film Corp Electrophotographic process
US3443936A (en) * 1964-08-20 1969-05-13 Agfa Gevaert Ag Process for the production of electrophotographic images
US3561958A (en) * 1967-04-07 1971-02-09 Xerox Corp Inducing frost deformation imaging by electrolytic deposition
US3517995A (en) * 1967-10-02 1970-06-30 Xerox Corp Method and apparatus for increasing the efficiency of corona charging

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3789223A (en) * 1970-08-11 1974-01-29 Fuji Photo Film Co Ltd Charging method for relatively movable electrophotographic means and corona means
US3766428A (en) * 1972-07-24 1973-10-16 Westinghouse Electric Corp High resolution, high intensity cathode ray tube
US4195991A (en) * 1977-10-21 1980-04-01 James River Graphics Inc. Electrographic recording method of applying an electric field opposite the charge retaining layer
US5116714A (en) * 1989-02-06 1992-05-26 Sony Corporation Image forming material with developer and photosensitive base on which an electrostatic latent image is formed

Also Published As

Publication number Publication date
DE1939376A1 (de) 1970-03-19
GB1288395A (nl) 1972-09-06
FR2017608A1 (nl) 1970-05-22

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