US3393070A - Xerographic plate with electric field regulating layer - Google Patents

Xerographic plate with electric field regulating layer Download PDF

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Publication number
US3393070A
US3393070A US436171A US43617165A US3393070A US 3393070 A US3393070 A US 3393070A US 436171 A US436171 A US 436171A US 43617165 A US43617165 A US 43617165A US 3393070 A US3393070 A US 3393070A
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US
United States
Prior art keywords
plate
voltage
charging
xerographic
xerographic plate
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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
US436171A
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English (en)
Inventor
Snelling Christopher
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Xerox Corp
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Xerox Corp
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Publication date
Application filed by Xerox Corp filed Critical Xerox Corp
Priority to US436171A priority Critical patent/US3393070A/en
Priority to GB8540/66A priority patent/GB1141452A/en
Priority to JP41011136A priority patent/JPS499377B1/ja
Priority to DE19661522682 priority patent/DE1522682A1/de
Application granted granted Critical
Publication of US3393070A publication Critical patent/US3393070A/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
    • G03G15/00—Apparatus for electrographic processes using a charge pattern
    • G03G15/22—Apparatus for electrographic processes using a charge pattern involving the combination of more than one step according to groups G03G13/02 - G03G13/20
    • G03G15/28—Apparatus for electrographic processes using a charge pattern involving the combination of more than one step according to groups G03G13/02 - G03G13/20 in which projection is obtained by line scanning
    • G03G15/30—Apparatus for electrographic processes using a charge pattern involving the combination of more than one step according to groups G03G13/02 - G03G13/20 in which projection is obtained by line scanning in which projection is formed on a drum
    • 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
    • G03G5/14—Inert intermediate or cover layers for charge-receiving layers
    • G03G5/142—Inert intermediate layers
    • G03G5/144—Inert intermediate layers comprising inorganic material

Definitions

  • ABSTRACT OF THE DISCLOSURE This invention relates to xerography and, more specifically, to -a xerographic plate, method and apparatus.
  • Xerographic ofi'ice copying has undergone an extreme- 1y large growth in the past few years.
  • This copying technique as originally disclosed by Carlson in US Patent 2,297,691, and as further amplified by many related patents in the field, a photoconductive insulating layer making up part of a xerographic plate is first given a uniform electrostatic charge over its entire surface to sensitize it and is then exposed to an image of actinic electromagnetic radiation such as light, X-ray or the like, which selectively drains away the charge in illuminated areas of the photoconductive insulator leaving behind charge in the nonilluminated areas to form a latent electrostatic image.
  • actinic electromagnetic radiation such as light, X-ray or the like
  • This latent image is then made visible (developed) by the deposition of finely divided, electroscopic, marking material on the surface of the photoconductive insulating layer as a result of which the marking material conforms to the pattern of the latent image rendering it visible.
  • the marking material is generally made up of a powdered mixture of a thermoplastic and a colorant and is known in the art as toner.
  • this visible toner image is then transferred to a second surface such as a sheet of paper and fixed in place thereon to form a permanent, visible reproduction of the original.
  • a cheap nonreusable photoconductive insulating material is employed, the toner particles are fixed in place directly on its surface with the consequent elimination of the transfer step from the process.
  • corona charging in order to sensitize it, a number of techniques have been developed and the technique which has gained widest commercial acceptance is corona charging, as more fully described in US. Patents 2,588,699 to Carlson and 2,777,957 to Walkup.
  • this corona discharge technique consists of spacing a filament or a plurality of filaments slightly from the surface of a xerographic plate having its conductive base grounded and applying a high potential to the filament so that an electrical corona discharge occurs between the filament and the plate, thus serving to deposit charged ions or electrons on the plate surface to raise its level of electrostatic charge with respect to ground potential.
  • the conditions of the atmosphere between the corona electrode and the xerographic plate to be sensitized can, in certain instances, make important differences in how effectively the plate is sensitized.
  • Reduced air pressure, wide changes in relative humidity, large amounts of impurities in the air and other factors may have relatively important effects upon the level of charge which is deposited upon the plate with the charging voltage held constant.
  • it is frequently necessary to adjust the power supply or use specialized charging devices such as screen-controlled corona discharge electrodes, as described for example in US. Patent 2,778,946 to Mayo, and even these techniques are not always entirely satisfactory.
  • Another instance in which corona voltage controls are required is a variable speed copier using a photoconductive plate which moves past the corona charging unit at two or more different speeds.
  • a still further object of this invention is to provide a xerographic plate which is self-limiting in its charge acceptance characteristics.
  • An additional object of this invention is to provide an improved xerographic process.
  • Yet another object of this invention is to provide a novel xerographic apparatus requiring no charging power supply adjustments or controls.
  • FIG. 1 is a side view of the improved xerographic plate according to this invention.
  • FIG. 2 is a graph of the current-voltage characteristics during corona charging of a conventional xerographic plate as compared with the improved xerographic plate of this invention.
  • FIG. 3 is a side sectional view of an exemplary xerographic processing apparatus employing the improved plate of this invention.
  • a xerographic plate generally indicated as 10 made up of supporting substrate 11, an interface layer 12 and a photoconductive insulating layer 13.
  • the substrate layer 11 may consist of any one of a number of materials including conductive materials such as aluminum, magnesium brass, steel, chrome, etc., or non-conductive materials such as glass, paper, plastic sheeting or the like impregnated with materials such as metals or carbon black which raise their conductivity or coated with conductive layers such as thin layers of gold, copper iodide, or the like.
  • conductive materials such as aluminum, magnesium brass, steel, chrome, etc.
  • non-conductive materials such as glass, paper, plastic sheeting or the like impregnated with materials such as metals or carbon black which raise their conductivity or coated with conductive layers such as thin layers of gold, copper iodide, or the like.
  • a conductive substrate not only provides additional structural strength to the plate, but also provides for an electrical ground plane immediately beneath the surface of the other plate layers so that the plate may be easily charged from a corona discharge electrode in accordance with the teachings of the aforementioned US. Patent 2,588,699.
  • the conductive material need not necessarily be a material which is ordinarily thought of as an electrical conductor. Any substrate having an electrical resistance at least several orders of magnitude lower than the resistance of the illuminated photoconductor will serve this function even without a metallic coating. If on the other hand, certain other corona charging techniques such as the two-sided corona charging technique, described in U.S. Patent 2,922,883 are employed, the conductivity of the supporting substrate may be largely ignored and it may be selected based mainly on its structural properties or omitted altogether.
  • Interface layer 12 is a thin layer of a material which is selected primarily for its electrical properties, as described hereinafter in connection with FIG. 2. In essence, it is a material which is selected so as to impart to the plate a voltage or field regulating electrical characteristic similar to that of a voltage-regulating gas discharge tube. Any suitable voltage regulating material may be employed for this purpose. Typical materials which have been found to provide this voltage regulating characteristic include: bismuth, oxidized bismuth, tin, copper selenide, and extremely thin layers of tin oxide or aluminum oxide, etc. The tin oxide and aluminum oxide layers must be very thin in order to achieve this characteristic I.V. curve.
  • a photoconductive insulating layer 13 Overlying interface layer 12 is a photoconductive insulating layer 13. Any suitable photoconductive insulating material may be employed as layer 13. Typical photoconductive insulators include: vitreous selenium, alloys of selenium with arsenic or tellurium in the vitreous form, sintered or evaporated layers of other materials such as cadmium sulfide, cadmium selenide, etc., photoconductive insulating materials in particulate form suspended in an insulating film-forming binder material as, for example, zinc sulfide, zinc cadmium sulfide, French process zinc oxide, metal-free phthalocyanine, cadmium sulfide, cadmium selenide, zinc silicate, cadmium sulpho-selenide, etc., dispersed in an insulating film-forming binder such as an epoxy resin, a silicone resin, an alkyd resin or the like.
  • Typical organic photoconductive materials of this type include: polyvinylcarbazole, anthracene, polyvinylanthracene, anthraquinone, oxidiazole derivatives such as 2,5-bis-(p-aminophenyl-l), 1,3,4 oxidiazole; Z-phenylbenzoxazole; and charge transfer complexes made by complexing resins such as phenolaldehydes, epoxies, phenoxies, polycarbonates, melamines, etc.
  • Lewis acids such as phthalic anhydride, 2,4,7-trinitrofluorenone, metallic chlorides such as aluminum, zinc or ferric chloride; 4,4-bis(dimethylamino)benzophenone; chloranil; picric acid; 1,3,5-trinitrobenzene; l-chloroanthraquinone; bromal; 4-nitrobenzaldehyde; 4-nitr-ophenol; acetic anhydride; maleic anhydride; borontrichloride; maleic acid; cinnamic acid; benzoic acid; tartaric acid; malonic acid and mixtures thereof.
  • Lewis acids such as phthalic anhydride, 2,4,7-trinitrofluorenone, metallic chlorides such as aluminum, zinc or ferric chloride; 4,4-bis(dimethylamino)benzophenone; chloranil; picric acid; 1,3,5-trinitrobenzene; l-chloroanthraquinone; bromal; 4-nitrobenzaldehyde; 4-
  • selenium in its amorphous form and alloys of the amorphous form of selenium constitute a preferred material for photoconductive insulating layer 13, because of their extremely high quality image-making capability and relatively high light response.
  • FIG. 2 there is shown a graph of'the amount of current flow I through a xerographic plate versus the voltage on that plate V as corona charging proceeds.
  • Curve 16 represents a current-voltage characteristic of a conventional selenium xerographic plate on an aluminum substrate while curve 17 represents the current-voltage characteristic curve of the improved plate of this invention.
  • the selfregulating plate of this invention has a lower leg which very closely corresponds to that of the conventional xerographic plate until the voltage on the plate reaches a certain level where the curve turns up very sharply, rising to an almost straight vertical configuration so that increasing .plate current during charging results in little or no additional voltage being built up on the surface of the plate.
  • this curve 17 begins its steep rise depends upon the particular material selected for the interface 12, the thickness of the material and the particular overlying photoconductor.
  • the curve becomes vertical at about 30 volts per micron of selenium while it becomes vertical at about 40 volts per micron of selenium with the other interface materials listed supra.
  • FIG. 3 An exemplary xerographic copying apparatus adapted to employ the xerographic plate of this invention in the form of a cylindrical drum is shown in FIG. 3.
  • the drum when in operation, is generally rotated at a uniform velocity in the direction indicated by the arrow in FIG. 3 so after portions of the drum periphery pass the charging unit 18 and have been uniformly charged, they come beneath a projector 19 or other means for exposing the charged plate to the image to be reproduced. Subsequent to charging and exposure, sections of the drum surface move past the developing unit, generally designated 21.
  • This developing unit is of the gatorde type which includes an outer container or cover 22 with a trough at its bottom containing a supply of developing material 23.
  • the developing material is picked up from the bottom of the container and dumped or cascaded over the drum surface by a number of "buckets 24 on an endless driven conveyor belt 26.
  • This development technique which is more fully described in US. Patent 2,618,552 to Wise and 2,618,551 to Walkup, utilizes a two-element development mixture including finely divided, colored marking particles or toner and larger carrier beads.
  • the carrier beads serve both to deagglomerate the fine toner particles for easier feeding and charge them by virtue of the relative positions of the toner and carrier material in the triboelectric series.
  • the carrier beads with toner particles clinging to them are cascaded over the drum surface.
  • the electrostatic field from the charge pattern on the drum pulls toner particles off the carrier beads serving to develop the image.
  • the toner in the developing mixture is periodically replenished from a toner dispenser not shown.
  • a transfer unit 29 is placed behind the web and spaced slightly from it between rollers 28. This unit is similar in nature to the plate charging mechanism 18 in that both operate on the corona discharge principle.
  • Both the charging device 18 and the transfer unit 29 are connected to a source of high DC potential (of the same polarity) identified as 31 and 32, respectively, and include a corona discharge Wire 33 and 34, respectively, surrounded by a conductive metal shield.
  • a source of high DC potential identified as 31 and 32, respectively, and include a corona discharge Wire 33 and 34, respectively, surrounded by a conductive metal shield.
  • voltage ource 31 is preselected to be of such a magnitude that it will produce a corona discharge on the drum under almost any conditions of relative humidity and atmospheric pressure normally encountered which would tend to charge a conventional xerographic plate well above the desired voltage.
  • This excessively high potential source is pre-set and need not be adjusted because the retained voltage on the plate is controlled by the electrical characteristics of the plate itself in such a way that any excessive current which flows through the plate during the corona discharge is drained away by the voltage regulating characteristics of the plate.
  • this voltage is generally set at from about 8,000 volts to about 10,000 volts, whereas with a conventional plate, it would be set at about 7,000 volts.
  • charge is deposited on the back of web 27 and this charge is of the same polarity as the charge initially deposited on the drum and also opposite of polarity to the toner particles utilized in developing the drum.
  • the discharge deposit on the back of web 27 pulls the toner particles away from the drum by overcoming the force of attraction between the particles and the charge on the drum.
  • a roller connected to a high potential source opposite in polarity to the toner particles may be placed immediately behind the copy web or the copy web itself may be adhesive to the toner particles.
  • the web moves beneath a fixing unit 36 which serves to fuse or permanently fix the toner image to web 27.
  • a resistance heating-type fixer is illustrated.
  • this apparatus may also be operated at varying speeds by setting the corona discharge unit at a high enough voltage so the plate will be charged fully at the highest speed. Then, overcharging will not occur at the lower speeds because of self regulation by the plate.
  • a xerographic plate comprising an electrically c0n ductive substrate, an electrical field regulating layer on said substrate consisting essentially of bismuth, and a photoconductive insulating layer overlaying said voltage regulating layer.
  • a xerographic plate comprising an electrically conductive substrate, an electrical field regulating layer on said substrate consisting essentially of oxidized bismuth, and a photoconductive insulating layer overlaying said voltage regulating layer.
  • a xerographic plate comprising an electrically conductive substrate, an electrical field regulating layer on said substrate consisting essentially of tin, and a photoconductive insulating layer overlaying said voltage regulating layer.
  • a xerographic plate comprising an electrically conductive substrate, an electrical field regulating layer on said substrate consisting essentially of copper selenide, and a photoconductive insulating layer overlaying said voltage regulating layer.
  • a method of uniformly charging a xerographic plate having a voltage regulating layer comprising an electrically conductive support, an electrical field regulating layer comprising a material selected from the group consisting of bismuth, oxidized bismuth, tin, and copper selenide contained on said substrate, and a photoconductive insulating layer overlaying said voltage regulating layer, said method comprising uniformly charging said plate to a charging potential in excess of a preselected voltage determined by said voltage regulating layer.

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  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Chemical & Material Sciences (AREA)
  • Inorganic Chemistry (AREA)
  • Photoreceptors In Electrophotography (AREA)
  • Electrostatic Charge, Transfer And Separation In Electrography (AREA)
US436171A 1965-03-01 1965-03-01 Xerographic plate with electric field regulating layer Expired - Lifetime US3393070A (en)

Priority Applications (4)

Application Number Priority Date Filing Date Title
US436171A US3393070A (en) 1965-03-01 1965-03-01 Xerographic plate with electric field regulating layer
GB8540/66A GB1141452A (en) 1965-03-01 1966-02-25 Xerographic plate
JP41011136A JPS499377B1 (enrdf_load_stackoverflow) 1965-03-01 1966-02-25
DE19661522682 DE1522682A1 (de) 1965-03-01 1966-03-01 Xerographische Platte

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US436171A US3393070A (en) 1965-03-01 1965-03-01 Xerographic plate with electric field regulating layer

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US3393070A true US3393070A (en) 1968-07-16

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US (1) US3393070A (enrdf_load_stackoverflow)
JP (1) JPS499377B1 (enrdf_load_stackoverflow)
DE (1) DE1522682A1 (enrdf_load_stackoverflow)
GB (1) GB1141452A (enrdf_load_stackoverflow)

Cited By (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3864132A (en) * 1972-05-22 1975-02-04 Eastman Kodak Co Article having a hydrophilic colloid layer adhesively bonded to a hydrophobic polymer support
US3920453A (en) * 1972-01-28 1975-11-18 Addressograph Multigraph Method of electrostatic duplicating by image transfer
US4094675A (en) * 1973-07-23 1978-06-13 Licentia Patent-Verwaltungs-G.M.B.H. Vapor deposition of photoconductive selenium onto a metallic substrate having a molten metal coating as bonding layer
US4138262A (en) * 1976-09-20 1979-02-06 Energy Conversion Devices, Inc. Imaging film comprising bismuth image-forming layer
US4271257A (en) * 1976-09-20 1981-06-02 Energy Conversion Devices, Inc. Imaging film of bismuth or bismuth alloy
US4403026A (en) * 1980-10-14 1983-09-06 Canon Kabushiki Kaisha Photoconductive member having an electrically insulating oxide layer
US4518669A (en) * 1982-11-06 1985-05-21 Canon Kabushiki Kaisha Electrophotographic photosensitive member
US4705696A (en) * 1984-09-27 1987-11-10 Olin Hunt Specialty Products Inc. Method of making a lithographic printing plate, printing plates made by the method, and the use of such printing plates to make lithographic prints
US5085959A (en) * 1988-08-11 1992-02-04 Fuji Electric Co., Ltd. Se or se alloy electrophotographic photoreceptor
US5468584A (en) * 1992-12-01 1995-11-21 Canon Kabushiki Kaisha Electrophotographic photosensitive member having intermediate layer containing fine powder particles of tin oxide containing phosphorous and apparatus employing same

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS52108169U (enrdf_load_stackoverflow) * 1976-02-12 1977-08-17

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB748340A (en) * 1952-07-23 1956-04-25 Haloid Co Xerographic plate and the process for production thereof
US2863768A (en) * 1955-07-05 1958-12-09 Haloid Xerox Inc Xerographic plate
US3041166A (en) * 1958-02-12 1962-06-26 Xerox Corp Xerographic plate and method
US3148057A (en) * 1961-03-23 1964-09-08 Azoplate Corp Material for electrophotographic purposes
US3210194A (en) * 1961-08-21 1965-10-05 Univ Iowa State Res Found Inc Administration of 2-mercaptoimidazole compounds to meat-producing ruminants
US3243293A (en) * 1965-03-26 1966-03-29 Xerox Corp Plate for electrostatic electro-photography

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB748340A (en) * 1952-07-23 1956-04-25 Haloid Co Xerographic plate and the process for production thereof
US2863768A (en) * 1955-07-05 1958-12-09 Haloid Xerox Inc Xerographic plate
US3041166A (en) * 1958-02-12 1962-06-26 Xerox Corp Xerographic plate and method
US3148057A (en) * 1961-03-23 1964-09-08 Azoplate Corp Material for electrophotographic purposes
US3210194A (en) * 1961-08-21 1965-10-05 Univ Iowa State Res Found Inc Administration of 2-mercaptoimidazole compounds to meat-producing ruminants
US3243293A (en) * 1965-03-26 1966-03-29 Xerox Corp Plate for electrostatic electro-photography

Cited By (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3920453A (en) * 1972-01-28 1975-11-18 Addressograph Multigraph Method of electrostatic duplicating by image transfer
US3864132A (en) * 1972-05-22 1975-02-04 Eastman Kodak Co Article having a hydrophilic colloid layer adhesively bonded to a hydrophobic polymer support
US4094675A (en) * 1973-07-23 1978-06-13 Licentia Patent-Verwaltungs-G.M.B.H. Vapor deposition of photoconductive selenium onto a metallic substrate having a molten metal coating as bonding layer
US4138262A (en) * 1976-09-20 1979-02-06 Energy Conversion Devices, Inc. Imaging film comprising bismuth image-forming layer
US4271257A (en) * 1976-09-20 1981-06-02 Energy Conversion Devices, Inc. Imaging film of bismuth or bismuth alloy
US4403026A (en) * 1980-10-14 1983-09-06 Canon Kabushiki Kaisha Photoconductive member having an electrically insulating oxide layer
US4518669A (en) * 1982-11-06 1985-05-21 Canon Kabushiki Kaisha Electrophotographic photosensitive member
US4705696A (en) * 1984-09-27 1987-11-10 Olin Hunt Specialty Products Inc. Method of making a lithographic printing plate, printing plates made by the method, and the use of such printing plates to make lithographic prints
US5085959A (en) * 1988-08-11 1992-02-04 Fuji Electric Co., Ltd. Se or se alloy electrophotographic photoreceptor
US5468584A (en) * 1992-12-01 1995-11-21 Canon Kabushiki Kaisha Electrophotographic photosensitive member having intermediate layer containing fine powder particles of tin oxide containing phosphorous and apparatus employing same

Also Published As

Publication number Publication date
JPS499377B1 (enrdf_load_stackoverflow) 1974-03-04
GB1141452A (en) 1969-01-29
DE1522682A1 (de) 1969-10-30

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