US3825421A - Process for forming an image on insulative materials - Google Patents

Process for forming an image on insulative materials Download PDF

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Publication number
US3825421A
US3825421A US00193890A US19389071A US3825421A US 3825421 A US3825421 A US 3825421A US 00193890 A US00193890 A US 00193890A US 19389071 A US19389071 A US 19389071A US 3825421 A US3825421 A US 3825421A
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United States
Prior art keywords
powder
photoconductive
layer
image
electroconductive
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Expired - Lifetime
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US00193890A
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English (en)
Inventor
Y Tamai
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Fujifilm Holdings Corp
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Fuji Photo Film Co Ltd
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    • GPHYSICS
    • G03PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03GELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
    • G03G15/00Apparatus for electrographic processes using a charge pattern
    • G03G15/22Apparatus for electrographic processes using a charge pattern involving the combination of more than one step according to groups G03G13/02 - G03G13/20
    • G03G15/34Apparatus for electrographic processes using a charge pattern involving the combination of more than one step according to groups G03G13/02 - G03G13/20 in which the powder image is formed directly on the recording material, e.g. by using a liquid toner
    • G03G15/342Apparatus for electrographic processes using a charge pattern involving the combination of more than one step according to groups G03G13/02 - G03G13/20 in which the powder image is formed directly on the recording material, e.g. by using a liquid toner by forming a uniform powder layer and then removing the non-image areas
    • GPHYSICS
    • G03PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03GELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
    • G03G5/00Recording members for original recording by exposure, e.g. to light, to heat, to electrons; Manufacture thereof; Selection of materials therefor
    • G03G5/10Bases for charge-receiving or other layers
    • YGENERAL 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
    • Y10TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10STECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10S430/00Radiation imagery chemistry: process, composition, or product thereof
    • Y10S430/001Electric or magnetic imagery, e.g., xerography, electrography, magnetography, etc. Process, composition, or product
    • Y10S430/101Photoconductive powder

Definitions

  • This invention relates to an improvement in electrophotographic processes, and particularly relates to an improvement in an electrophotographic scribing or image formation process on an insulative material utilizing photoconductive particles as the photoconductive element therein.
  • This electrophotographic process consists of the steps of first dispersing a photoconductive powder and then electrostatically charging the photoconductive powder, or else dispersing a previously charged photoconductive powder, followed by additional charging if desirable, on an electroconductive support material, subjecting the thus dispersed and charged powder to imagewise exposure of an original image, removing the powder of which the electrostatic charge is dissipated or decreased by exposure, and either-fixing the remaining powder in situ or after transfer thereof.
  • the photoconductive powder used consists of a photoconductive material and powder core material provided therein having an absorption coefiicient not exceeding 1.3)( mm.- for the major part of the radiation in the sensitive wavelength region of the photoconductive material. This process is capable of reproducing clear, sharp images on electroconductive plates and is employed in electrophotographic platemarking apparatus for scribing onto steel plates etc.
  • FIG. 1 is a cross sectional view of an example of photoconductive particles employed in the process of the present invention
  • FIGS. 2-8 are schematic side-views showing the steps of a scribing process for an insulative material according to the present invention.
  • the insulative material employed in the invention can be in any shape, e.g., a fiat plate. It will be apparent to one skilled in the art that the exact shape of the insulative material does not form a part of the present invention.
  • the electroconductive powder to be dispersed on said insulative material can be a metal powder, metal spheres, a resin powder covered with metal, electroconductive carbon spheres, a resin powder covered with electroconductive carbon, glass spheres covered with an electroconductive tin oxide layer, cuprous iodide etc.
  • any powder be it homogeneous or composite, which is capable of carrying an electric current without degradation may be used in the present invention.
  • the electroconductive powder preferably has a diameter ranging from 5 microns to 2 millimeters.
  • the preferred electroconductive powders have a conductance greater than 1x10 v. cm. specific surface conductance (the conductance determined when electrodes having 1 unit length are disposed in parallel having with a distance 1 unit between them) when the powders are laid on the insulating base.
  • the most preferred specific surface conductance range is ca. 10 -10 v. cm. but it is to be understood such range is. not mandatory.
  • particles having a diameter of 50 to 500p. such as'glass balls, siliceous sand, alumina, china and the like coated on their surface with a mixture of carbon black and a resin, or
  • FIG. 1 shows a cross section of one example of a photoconductive powder particle employed in this invention.
  • the photoconductive particle 35 is composed of a transparent core 11 and a photoconductive insulative layer 12 thereabout.
  • the transparent core 11 preferably has an absorption coefficient not exceeding 1.3 mm.- for the major part of the radiation in the sensitive wavelength region of the photoconductive layer 12 (for best results a $50 m shift from the peak).
  • at least one of the core material 11 or the insulative photoconductive layer 12 contains a thermoplastic resin material or a material which is soluble in a suitable solvent which can be applied to achieve fixing.
  • Suitable solvents for fixing will, of course, depend on the material to be marked and the resinous material, if used, in the photoconductive powder; generally speaking, trichloroethylene, tetrachloroethylene, acetone, MEK, MIBK, ethyl acetate, propyl or butyl acetate, toluene, xylene are used.
  • photoconductive particles for use in the present invention are those disclosed in British Pat. No. 1,165,017.
  • the photoconductive particles will have a size of 10 to 200 microns, with a size of to 80 microns being most preferred.
  • the thickness of the photoconductive particle layer is generally in accordance with such layers as are known to the art, and must be sufficient to permit the layer to perform its image-yielding function.
  • a thickness of at least two of the smaller sized photoconductive particles is required, and thus the preferred photoconductive layers have a thickness of 20 to 200 microns, though obviously thicker layers can be used.
  • using particles of a specific gravity of 1.3 as disclosed in the above British patent a layer thickness of over 20 microns is used.
  • a surface voltage of about 350 volts or greater is generally used.
  • thermoplastic resin materials include polymethylmethacrylate, polystyrene, poly a-methylstyrenc, polyamide, polycarbonate, polyvinylchloride, polyvinylbutyral and the like, which are polymerized or condensed polymers having a secondary transition point higher than room temperature, e.g., in the range 80 to 200 C.
  • FIG. 2 shows the step of electrostatic charging on the surface of an insulative flat plate 14 on which the image is to be reproduced.
  • the insulative plate 14 is placed on an electroconductive support plate 13 and exposed to corona discharge generated by corona electrode 15 provided in shield case 16 moving above the surface of plate 14.
  • the corona electrode 15 is externally supplied with a high electric potential (a negative potential in this case).
  • Electrostatic charging can also be carried out by other charging processes known to the art such as frictional charging. The exact charging method'is not of great importance.
  • Electroconductive powder 22 is dispersed as shown in FIG. 3 onto the surface of .thus charged insulative plate 14 from a reservoir 21 to form a uniform layer.
  • FIG. 4 shows the dispersion of electroconductive powder 22 on the surface of an insulative material of irregular shape.
  • the electroconductive powder 22 contained in a container provided with an appropriate outlet thereunder is made .to fallonto the surface of the material 31 in a layer and is simultaneously exposed to a corona discharge generated by the corona electrode 15, thereby being deposited in a uniform layer on the surface thus charged.
  • v 7
  • FIG. 5 shows the step of dispersing photoconductive particles 35 on the insulative material 14 which already is provided with a layer of electroconductive powder 22 by means of the step explained in FIG. 4.
  • the photoconductive particles 35 supplied from the conta ner are electrostatically charged by means of corona discharge electrode 33 and dispersed on the layer of electroconductive powder 22.
  • Uniform dispersion of said photoconductive particles can be accomplished, for example, by the dispersing device disclosed in lap. Pat.' Pub. 8,838/70 in which the powder is dispersed as solid-gas sol. It is naturally also possible to apply electrostatic charging to said particles after dispersion thereof.
  • FIG. 6 shows the step of development with air et after imagewise exposure thereon.
  • the photoconductive particles 35 in the exposed area B lose their electrostatic charge and are eliminated by the air jet supplied by duct 36 displaced in the direction of arrow. 35 indicates the photoconductive particles thus removed by the air jet and collected in a duct 37 of reduced pressure.
  • the air jet supplied from the duct 36 is regulated so as to not remove the photoconductive particles in the unexposed area.
  • the electroconductive powder 22 be firmly retained on the insulative material 14, since the separation of this powder from the recovered photoconductive particles 35' at the cycled use thereof.
  • the insulative material 14 is required to be highly insulative, and preferably has a resistivity of about 10 ohm.cm or higher most preferably 10 ohm.cm or higher.
  • the conductive-powder cannot be retained stably on the surface of insulative ma: terial 14 and is apt to contaminate therecovered photoconductive particles. To allow forthe case where such might happen, it is preferred to have a difference in specific gravity or magnetic properties between the electroconductive powder and the photoconductive particles to facilitate the separation thereof. 3 r w u w FIG.
  • FIG. 7 shows the step of fixing the image consisting of the photoconductive particles by means of a fixing head. displaced in the direction of the arrow after the abovementioned steps.
  • a solvent 42 contained in the container 41 is sprayed in mist form 44 from a nozzle 43.
  • the component soluble in the solvent (the resinous component in most cases) in the photoconductive particles is dissolved and firmly sticks onto the surface of insulative material 14 together with the photoconductive particles in the unexposed area A to form the fixed image 45.
  • the electroconductive powder 22 is composed of a material insolu-l ble in the solvent, such as a me'tal, the electroconductive powder is not dissolved by the sprayed solvent and therefore is not fixed onto the insulativematerial 14. whenI said solvent is evaporated.
  • the solvent 42 is preferably one which does not dissolve the insulative material 14 or der 22.
  • the electroconductive powder 22 sticking to the nonimage area B can be removed by exposing the assembly to a corona discharge of inverted polarity with respect to that employed in the step shown in-FIG. 2 or of an alternating polarity, to thereby eliminate the electrostatic charge remaining thereon.
  • An'air jet may then be used to remove'the powder 22 at area B.
  • Mechanical elimination of the charge and removal by means, for example, of a brush are among alternative removal procedures.
  • Charge elimination can also be achieved by the presence of a small amount of non-film-forming antistatic agent in the solvent 42 employed in the step of FIG. 7, or by passing the insulative material through grounded electroconductive particles as explained in lap. Pat. Pub. 3,669/ 69.
  • FIG. 8 shows the image 45 containing the electroconductive powder 22 thus formed on the insulative material 14 according to the process of this invention thus far explained.
  • this invention enables one to electrophotographically obtain an image on the surface of an insulative material.
  • the process of this invention is applicable to insulative materials and materials provided with an insulative surface, such as a metal plate provided thereon with a resinous layer, a metal plate provided thereon with an .enameled layer, moulded plastics, plastic sheets, glass plates, glass blocks, glass bottles, etc.
  • the electroconductive pow- Example I On an electrostatically charged polyethylene terephthalate film, a finely divided black powder comprising parts of carbon black and 10 parts of phenol resin, having a mean particle diameter of about 5014 was cascaded. The charging of the film was carried out by a negative corona. The black conductive powder uniformly adhered on the film surface. The weight of the powder layer was 25 g./m. 30 g./m. and the layer showed a surface resistance of about 10* cm./square. On this black layer there was again spread a photoconductive powder which had been prepared according to the method described in Example I in British Patent 1,165,017. The coated weight of this second layer was about 85-110 g./m.
  • the covered film was subjected to a negative corona with its carbon layer connected to ground.
  • the initial potential of the top was 400 volts.
  • An optically positive image was projected and the film was subjected to an air stream. Whereby the photoconductive powder remained only at the non-irradiated area giving a white image against a dark background.
  • Fixing of the image was carried out by spraying cyclohexane onto the film whereby the conductive powder did not dissolve at all. Then after the evaporation of the solvent, the conductive powder at the background area was eliminated.
  • Example II A piece of glass plate was covered with silver coated small glass beads having a diameter of about 50m with silver chemically plated thereon.
  • the coated weight of the beads was 40 g./m.
  • the coating weight was about 150 g./m.
  • an air stream was carefully applied onto the plate to glow off only the photoconductive powder at the irradiated portion.
  • the photoconductive powder image was then fixed by spraying trichloroethylene thereon. After the evaporation of the solvent, the conductive powderwas removed by brushing.
  • a process for forming an image on material comprising the steps of:
  • said photoconductive particles comprise a photoconductive insulative layer about a transparent core having an absorption coefiicient no greater than 1.3)(10 mm.- for the major portion of the sensitive wave length region of the insulative layer.
  • a process for forming an image on an insulative material having a resistivity of at least 10 ohm.cm. comprising the steps of:
  • conducting layer of an electroconductive powder on one surface of said insulative material, said conducting layer having a specific surface conductance greater than 1x10 v. cm. and being formed of particles of a size of from 5 microns to 2 millimeters at least three layers deep;
  • an insulative forming a layer of photoconductiveparticles of a thickriess of 10 to 200 microns on the thin'formed and charged conducting layer, said layer of photoconductive particles having a thickness of atleast 20 microns;

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  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Photoreceptors In Electrophotography (AREA)
  • Developing Agents For Electrophotography (AREA)
US00193890A 1970-10-29 1971-10-29 Process for forming an image on insulative materials Expired - Lifetime US3825421A (en)

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JP45095488A JPS4916064B1 (ro) 1970-10-29 1970-10-29

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US3825421A true US3825421A (en) 1974-07-23

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US (1) US3825421A (ro)
JP (1) JPS4916064B1 (ro)
BE (1) BE774765A (ro)
CA (1) CA958755A (ro)
DE (1) DE2154146A1 (ro)
FR (1) FR2113343A5 (ro)

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3908037A (en) * 1971-09-14 1975-09-23 Xerox Corp Image developing techniques
US3926627A (en) * 1973-05-07 1975-12-16 Fuji Photo Film Co Ltd Process for making an electrophotographic image by use of photoconductive particles
US3926628A (en) * 1973-05-02 1975-12-16 Fuji Photo Film Co Ltd Using photoconductive and non-photoconductive powders
US3928655A (en) * 1973-03-05 1975-12-23 Fuji Photo Film Co Ltd Electrostatic powder coating method
US3982938A (en) * 1973-02-13 1976-09-28 Fuji Photo Film Co., Ltd. Photoconductive toners which include photoconductive pigment particles in a charge-transporting insulating binder
US3998634A (en) * 1973-04-24 1976-12-21 Fuji Photo Film Co., Ltd. Powder electrophotographic method
EP0165319A1 (en) * 1983-11-30 1985-12-27 Matsushita Electric Industrial Co., Ltd. Method of forming image

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4105449A (en) * 1973-08-17 1978-08-08 Sekisui Kagaku Kogyo Kabushiki Kaisha Extruded electrophotographic recording material
JPS5296133A (en) * 1976-02-05 1977-08-12 Youichi Muramatsu Golf practice stand

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3908037A (en) * 1971-09-14 1975-09-23 Xerox Corp Image developing techniques
US3982938A (en) * 1973-02-13 1976-09-28 Fuji Photo Film Co., Ltd. Photoconductive toners which include photoconductive pigment particles in a charge-transporting insulating binder
US3928655A (en) * 1973-03-05 1975-12-23 Fuji Photo Film Co Ltd Electrostatic powder coating method
US3998634A (en) * 1973-04-24 1976-12-21 Fuji Photo Film Co., Ltd. Powder electrophotographic method
US3926628A (en) * 1973-05-02 1975-12-16 Fuji Photo Film Co Ltd Using photoconductive and non-photoconductive powders
US3926627A (en) * 1973-05-07 1975-12-16 Fuji Photo Film Co Ltd Process for making an electrophotographic image by use of photoconductive particles
EP0165319A1 (en) * 1983-11-30 1985-12-27 Matsushita Electric Industrial Co., Ltd. Method of forming image
EP0165319A4 (en) * 1983-11-30 1987-11-09 Matsushita Electric Ind Co Ltd METHOD FOR REPRESENTING AN IMAGE.

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DE2154146A1 (de) 1972-05-04
JPS4916064B1 (ro) 1974-04-19
CA958755A (en) 1974-12-03
BE774765A (fr) 1972-02-14
FR2113343A5 (ro) 1972-06-23

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