US3926627A - Process for making an electrophotographic image by use of photoconductive particles - Google Patents

Process for making an electrophotographic image by use of photoconductive particles Download PDF

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US3926627A
US3926627A US453421A US45342174A US3926627A US 3926627 A US3926627 A US 3926627A US 453421 A US453421 A US 453421A US 45342174 A US45342174 A US 45342174A US 3926627 A US3926627 A US 3926627A
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Prior art keywords
substrate
layers
particles
charges
photoconductive
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Masakazu Iwasa
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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
    • G03G15/22—Apparatus for electrographic processes using a charge pattern involving the combination of more than one step according to groups G03G13/02 - G03G13/20
    • G03G15/34—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 the powder image is formed directly on the recording material, e.g. by using a liquid toner
    • G03G15/342—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 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
    • 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
    • Y10S430/101—Photoconductive powder
    • 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

  • Photoconductive particles are applied in a plurality of layers on a substrate having an insulating surface.
  • the surface of the photoconductive particle layers is uniformly charged and exposed to imagewise light. By the exposure, the charges in the upper layers in the exposed area of the image are moved to the lower layers.
  • the charges in the non-exposed area are neutralized by DC. corona discharge in the reverse polarity or by AC. corona discharge.
  • the particles on the substrate are removed by air blow leaving only the particles in the lower layers of the non-exposed area which are electrostatically attracted by the insulating surface.
  • the particle conductive image can also be formed on a substrate by applying precharged 29 Claims, 12 Drawing Figures no. ⁇ 30 0310310101030, or on. 99999.0 ⁇ 3b U.S. Patent Dec. 16,1975 Sheet 1 of4 3,926,627
  • This invention relates to a process for making an electrophotographic image by use of photoconductive particles, and more specifically to a process for making an electrophotographic image on an insulating substrate by use of photoconductive particles serving as developer particles.
  • the electrophotographic image forming process in accordance with this invention is also capable of forming a particle image on a conductive substrate by use of photoconductive particles.
  • the photoconductive particles used in this invention are colored toner made of photoconductive material.
  • an electrostatic latent image is formed on a uniformly charged photoconductive surface by exposure to imagewise light.
  • imagewise light By exposure to the imagewise light, the charges in the exposed area of the image are neutralized and an electrostatic latent image is formed. Therefore, one surface of the photoconductive layer is required to be in contact with a conductive layer having surface resistance of not higher than about so that the charges may move away from the photoconductive layer in the exposed area.
  • Another object of the present invention is to provide a process for making an electrophotographic image either on an insulating or conductive substrate by use of photoconductive particles applied on the substrate.
  • the process for making the electrophotographic image in accordance with the present invention comprises the steps of applying photoconductive particles on a substrate, uniformly charging the particles, exposing the particles to imagewise light to form an internal latent image in the particle layer, charging the surface of the particle layer in the reverse polarity to neutralize the charges on the surface of the particle layer, and removing the neutralized particles to leave only the charged particles attracted by the insulating substrate in the exposed area of the image.
  • the developed image formed by selectively removing the particles is fixed by, for instance, a solvent fixing process.
  • the uniform charging of the particles and the imagewise exposure are performed at the same time.
  • the particles are charged before being applied on the surface of the insulating substrate and the imagewise exposure of the particle layer is performed simultaneously with the neutralization of the charges in the particles.
  • a positive image is obtained from a positive original.
  • the electrophotographic image can be formed on an insulating substrate without a conductive base,
  • the uniform charging is performed by use of a pair of corona discharging electrodes of opposite polarities. Further, in neutralizing the charges, there is used a pair of AC. corona discharging electrodes located one on either side of the insulating substrate.
  • the process for making an electrophotographic image in accordance with this invention is applicable not only to the dry type copying machine but also to a variety of recording machines including, for example, an electrostatic print marking system by which lines are marked on a steel plate utilizing the electrostatic recording principle for facilitating the marking work in the shipbuilding industry.
  • the photoconductive material used for the photoconductive particles a variety of photoconductive materials including sulfides, oxides and selenides of zinc, cadmium and the like can be used.
  • the photoconductive material is dispersed in a binder resin and processed so as to be chargeable in either positive or negative porality.
  • zinc oxide, mercury sulfide, lead sulfide, tellurium compound, titanium dioxide, cadmium sulfide, and cadmium sulfide-carbonate are effectively used.
  • Organic photoconductors such as metal-free phthalocyanine and polyvinylcarbazole can be used as the material for the photoconductive material.
  • any resin which can be used for the ordinary electrofax photosensitive layer can be used.
  • the resins which can be used as the binder are, for example, alkyd resins, styrene-modified or acryl-modified alkyd, rosin-modified or phenol-modified alkyd, epoxy esters, terpene resins, buthylated melamine resins, copolymers of styrene and other copolymerizable monomers such as butadiene, acrylonitrilc, acrylic acid ester and methacrylic acid ester, vinyl chloride and vinyl acetate copolymer, partially saponified copolymers of vinyl chloride and vinyl acetate, polyvinyl acetate, copolymers of vinyl acetate and other vinyl monomers such as crotonic acid, acrylic acid ester and ethacrylic acid ester, homoand co-polymers containing acrylate or methacrylate and
  • the process in accordance with the present invention it is possible to use two or more kinds of photoconductive particles of different composition.
  • the photoconductive particles of different composition present different spectral sensitivity. Accordingly, it becomes possible to form a multi-color image by use of two or more kinds of photoconductive particles mixed together and scattered on an image recording medium.
  • the photoconductive particles employed in the process in accordance with the present invention are preferably finely granulated powders having a size of not larger than 50 microns in diameter and particles not larger than microns in diameter are particularly preferable.
  • the size of the particles is determined in accordance with the desired quality of image, particularly the resolution of the image. In other words, the resolution of the image is determined by the upper limit of the size of the particles used.
  • the particles must be able to maintain electrostatic charges in the dark for at least a period of time corresponding to the time of one cycle of the electrophotographic process which is not shorter than one minute after being subject to a high voltage of about several hundreds of volts.
  • the photoconductive particles are required to form a layer in which the charges are neutralized in response to exposure to activating illumination and the residual charge is lowered after the exposure to such radiation. From the viewpoint of commercial use of the electrophotographic process, it is desirable that the exposure time required be not longer than 30 seconds. Accordingly, the sensitivity of the particles to the radiation must be high enough to make an exposure time of longer than 30 seconds unnecessary.
  • the neutralization of the charges should preferably be completely made with an exposure time of about 0.001 to 10 seconds. With such a high sensitivity of the photoconductive particles to the exposure, it is possible to form the electrophotographic image with strobo flash light exposure.
  • FIGS. 1 to 6 show a first embodiment of the process for making an electrophotographic image in accordance with the present invention, in which;
  • FIG. 1 is a sectional elevation showing the first step of the first embodiment of the process in accordance with the invention wherein photoconductive particles 4 are applied on an insulating surface attached to a conductive electrode,
  • FIG. 2 is a sectional elevation showing the second step thereof wherein the particles are uniformly charged
  • FIG. 3 is a sectional elevation showing the third step thereof wherein the particles are exposed to imagewise light to form a latent image therein,
  • FIG. 4 is a sectional elevation showing the fourth step thereof wherein the charges on the particle layer are neutralized
  • FIG. 5 is a sectional elevation showing the fifth step thereof wherein the photoconductive particles are selectively blown away to form a visible particle image on the insulating surface
  • FIG. 6 is a sectional elevation showing the last step thereof wherein the developed visible particle image is fixed on the insulating surface
  • FIG. 7 is a sectional elevation showing the first step of an image forming process in accordance with the second embodiment of the present invention in which the uniform charging and the exposure to the image wise light are performed simultaneously,
  • FIG. 8 is a sectional elevation showing the second step of the second embodiment of the invention in which the charges on the particle layer are neutralized
  • FIG. 9 is a sectional elevation showing the first step of an image forming process in accordance with the third embodiment of the present invention in which the particles are applied on an image recording substrate simultaneously with the uniform charging thereof,
  • FIG. 10 is a sectional elevation showing the second step of the third embodiment of the present invention in which the exposure of the particles to the imagewise light and the neutralization of charges are performed simultaneously,
  • FIG. 11 is a sectional elevation showing one step of the fourth embodiment of the present invention in which no conductive electrode is used in contact with the insulating substrate and the particles are charged uniformly by use of a pair of corona discharging electrodes of opposite polarities, and
  • FIG. 12 is a sectional elevation showing another step of the fourth embodiment of the present invention in which the charges on the particle layer are neutralized by use of a pair of A.C. corona discharge electrodes located one on either side of the substrate bearing the particle layer.
  • FIGS. 1 to 6 show a first embodiment of the present invention
  • an insulating substrate 1 disposed on a conductive electrode 2 in contact therewith is used for recording an electrophotographic particle image thereon.
  • the first step of the first embodiment is shown in FIG. 1, in which a plurality of particle layers 3 consisting of a number of fme photoconductive particles 30 are formed on the surface of the insulating substrate 1 by use of a particle scattering device 4.
  • the conductive electrode is not absolutely necessary as understood from the descriptions hereinafter.
  • the purpose of the provision of the conductive electrode 2 is to provide a grounded electrode for the charging process and a bias electrode for the development process. Therefore, the insulating substrate 1 is not always required to be integrally fixed to the conductive electrode 2.
  • the insulating substrate 1 may be placed in contact with conductive electrode 2 so as to be easily peeled off or it may simply be placed on the conductive electrode 2.
  • the photoconductive particle layers 3 are subject to an electric field created by a DC. corona charger S which is impressed with a voltage by a D.C. source 6. Thus. the surface of the photoconductive particle layers 3 is uniformly charged.
  • the photoconductive particles 30 are of p-type and accordingly are positively charged.
  • the polarity in which the particles 30 are charged is minus.
  • the minus numeral 7 indicates the plus charges imparted to the surface of the photoconductive layers 3 and 8 indicates the nirnus charges induced in the conductive base plate or the electrode 2.
  • the uniformly charged photoconductive layers 3 are exposed to imagewise light 9 of activating radiation.
  • the electric resistance of the photoconductive particles 30 in the exposed area is lowered and the electric charges in the upper layer 3a of the photoconductive particles 30 are moved to the lower layer 3b of the photoconductive particles 30.
  • the charges in the exposed area are moved to the lower layer 3b of the photoconductive layers 3 as indicated at 10 and the charges in the non-exposed area remain in the upper layer 3a of the photoconductive layers 3 as indicated at 11 in FIG. 3.
  • the photoconductive layers 3 are subject to AC. corona charging in the dark by use of an AC. corona charger 12 which is impressed with an AC. voltage by a high voltage A.C. source 13 so that the surface charges II on the upper layer 3a of the photoconductive particle layers 3 are neutralized.
  • the charges 10 remaining in the lower layer 3b of the particle layers 3 are not neutralized by the AC. corona charging since these charges 10 are insulated by the photoconductive particles existing thereon in the upper layers of the particles.
  • an electrostatic latent image is formed by the A.C. corona charging.
  • the subsequent development step is illustrated in FIG. 5 in which the photoconductive particles 30 having no internal charges attracted by the charges 8 are blown away by an air blow.
  • a bias electrode I6 which is impressed with the voltage of the same polarity as that of the charges 10 imparted to the photoconductive particles 30a remaining on the surface of the insulating substrate 1 is located above the insulating substrate 1 with the particles 30a attached thereon.
  • the bias electrode I6 serves as a development electrode.
  • the bias electrode 16 and the conductive electrode 2 are connected to the opposite polarities of an electric source 17. Said air blow is made by a blower I8 moved laterally above the photoconductive particle layers 3.
  • a particle image is fon'ned on the surface of the insulating substrate 1 by the particles 30a remaining thereon.
  • the photoconductive particles 30 which are blown off from the surface of the insulating substrate 1 are restored and used again for the subsequent cycle of the image forming process.
  • Said bias electrode 16 serving as a development electrode has the effect of increasing the attraction between the disposed IO imparted to the plate attached thereto. particles 30a and the charges 8 remaining in the conductive electrode 2, whereby the range of allowance of the strength of said air blow for development is enlarged and the fog in the background of the image is reduced by making possible the blowing off of the particles with an air blow of great intensity.
  • the bias electrode 16 it is desirable to use the bias electrode 16. It is of course possible, however, for the formation of the particle image by the air blow to be conducted without the bias electrode 16.
  • the particle image which is formed on the insulating substrate 1 by the photoconductive particles 30a sticking to the surface thereof by the electrostatic force is fixed by means of well-known fixing methods such as heating, solvent fixing and pressure fixing.
  • An example of solvent fixing is shown in FIG. 6, in which a solvent 20 containing a component to soften the photoconductive particles is sprayed on the particle image formed on the insulating substrate 1 by use of spraying device 21.
  • the particle image is fixed on the insulating substrate l as shown at 22 in FIG. 6.
  • the scattering of the photoconductive particles 30 on the substrate 1, the uniform charging of the surface of the particle layers, the exposure to the imagewise light, and the AC. corona charging are sequentially performed. It is, however, possible to form the particle image even if the uniform charging by a D.C. corona charger and the imagewise exposure are performed simultaneously. Such a variation will now be described in detail as the second embodiment of the present invention referring to FIGS. 7 and 8.
  • photoconductive particles are applied on an insulating substrate 71 disposed on a conductive electrode 72 in a plurality of layers 73 by the same method as employed in the first embodiment shown in FIG. 1.
  • the photoconductive particle layers 73 are subject to an imagewise exposure 74 and a uniform charging by a D.C. corona charger 7S impressed with a high D.C. voltage by a D.C. source 76 simultaneously.
  • the uniform charging is performed by laterally moving the D.C. corona charger above the surface of the photoconductive layers 73. Consequently, the non-exposed portion of the photoconductive layers 73 is charged only on the surface thereof as indicated at 77.
  • the photoconductive particles 70a on the surface of the layers 73 are made conductive and the charges are moved to the internal or lower photoconductive particles 70b.
  • opposite charges 78 are induced.
  • the particles 70 are subject to an A.C. corona charging as shown in FIG. 8 so that the surface potential of the photoconductive particle layers 73 may be made zero by neutralizing the charges on the surface thereof by use of an A.C. corona charger 80 connected with an AC. source 81.
  • an A.C. corona charger 80 connected with an AC. source 81.
  • charges 79 of reverse polarity are induced so that the charges 77 on the unexposed area may be neutralized.
  • the development and fixing are performed similarly to those of the first embodiment as shown in FIGS. and 6.
  • the above embodiments concern the image formation of in a negative-to-positive type system in which a positive image is formed on an insulating substrate from a negative light image. It is, however. possible to perform a positive-to-positive type image formation by conducting the imagewise exposure and the neutralizing corona charging simultaneously. Further, in accordance with this process of the invention, the image can be formed on any type of substrate, insulating or conductive. Such a variation of the invention will now be described in detail as the third embodiment thereof referring to FIGS. 9 and 10. In accordance with this embodiment, the image can be formed on a conductive material having a partial insulating portion such as a steel plate having a partially coated portion covered with a dielectric coating like paint.
  • the photoconductive particles 90 are precharged before they are applied on the substrate 91.
  • a device 94 for applying particles 90 on the surface of the insulating substrate 91 is provided with a charger 95 mounted to the particle applying opening of the device 94 as shown in FIG. 9.
  • the charger 95 is electrically connected with a high voltage D.C. source 96.
  • the photoconductive particles 90 scattered on the surface of the insulating substrate 91 are imparted with a charge 97.
  • the charge 91 is for instance plus as illustrated in the drawing.
  • the polarity of the charge 91 is of course determined in accordance with the kind of the photoconductive material used in the particles 90 as mentioned in said first embodiment. Charges 98 of opposite polarity are induced in the conductive electrode 92 attached to the insulating substrate. The conductive electrode 92 is grounded at least during the process of uniform charging as indicated at 99.
  • the particles 90 are exposed to imagewise light 100 as illustrated in FIG. 10.
  • the light 100 is of course of the wavelength which is capable of activating the photoconductive particles 90.
  • the photoconductive particles 90 are subject to A.C. corona charging by means of an A.C. corona charger 101 connected with an A.C. source 102 as shown in FIG. 10.
  • the photoconductive particles 90a in the upper layer 930 in the non-exposed area are neutralized of their charge and the particles 90b in the lower layers 93!) in the non-exposed area are maintained to have the charge as illustrated in FIG. 10. Further, the charge of the photoconductive particles 90: in the exposed area is neutralized since the electric resistance thereof is lowered by the activating radiation of the imagewise light. It will be understood that the surface of the photoconductive particle layers 93 in the non-exposed area is provided with a small amount of compensating charges 103 so as to make the surface potential of the non-exposed area zero.
  • the charges in the exposed area are neutralized. Therefore, a positiveto-positive image formation can be performed.
  • the electrostatic latent image which has been formed by the above-described process can be made into a visible fixed image by the development and fixing process as mentioned in the foregoing embodiments.
  • this embodiment is applicable to the formation of an electrophotographic image on either a conductive substrate or a conductive substrate with a dielectric portion.
  • the contrast of the image is generally in proportion to the quantity of charge imparted to the photoconductive material or substrate.
  • a plurality of layers of photoconductive particles are used and the charges remain in a plurality of layers of the particles in the second and the third embodiments as shown in FIGS. 8 and 10. Therefore, an image of high contrast can be obtained by these embodiments of the invention.
  • the above-described embodiments employ an A. C. corona discharging device for neutralizing the charges remaining on the surface of the photoconductive particle layers
  • a DC. corona charging device of the reversed polarity instead thereof.
  • the polarity of the DC. charging device for neutralization of the charges of course must be opposite to that of the DC. corona charging device for uniformly charging the particles.
  • the polarity of the DC. corona charging device to be used for neutralization of the charge remaining in the photoconductive particles must be minus.
  • the level of the second D.C. charging device should desirably lower than that of the first uniformly charging D.C. charging device.
  • photoconductive particles are accumulated in a plurality of layers on an insulating substrate 111 which is not disposed on a conductive electrode or the like.
  • the surface of the photoconductive particle layers 113 and the back surface of the insulating substrate 111 are subject D.C. charging of the opposite polarities by means of a pair of DC. corona chargers 114 and 115 which are connected with DC. sources 116 and 117, respectively.
  • the surface of the photoconductive particle layers 113 and the back surface of the insulating substrate 111 are charged in the opposite polarities 118 and 119, respectively.
  • the result of this operation shown in FIG. 11 corresponds to the result of the uniform charging performed in the first embodiment as shown in FIG. 2. Therefore, the exposure of the particles 110 to the imagewise light is conducted in just the same manner as that conducted in the third step of the first embodiment as shown in FIG. 3. Thus, an electrostatic latent image is formed in the photoconductive particle layers 113.
  • the formation of the latent image as described immediately hereinabove corresponds to the similar step in the first embodiment as shown in FIG. 3.
  • the above modified step of forming the latent image on an insulating substrate which is not disposed on a conductive electrode can be performed in a similar way to that of the second and third embodiments. That is, the imagewise exposure in the variation corresponding to the second embodiment is performed simultaneously with the charging.
  • the imagewise exposure in the variation corresponding to the third embodiment is performed simultaneously with the neutralization of charges after the photoconductive particles which have been precharged by a charger provided in the particle scattering device are applied on the insulating substrate, and the back side of the insulating substrate is charged to the polarity opposite to that of the charges imparted to the particles.
  • the electrostatic latent image formed in the photoconductive particle layers 113 as described hereinabove is converted to a developable latent image by neutralization of the surface charges.
  • the neutralization the surface charges in the non-exposed area are all removed. Only in the exposed area, the charges remain in the lower layer of the photoconductive particle layers 113 as indicated at 1100 in FIG. 12.
  • EXAMPLE I As the photoconductive particles, EPM photoner made by Fuji Photo Film Co., Ltd. (photoconductive particles containing zinc oxide which is sensitized in the region of visible light and having an average diameter of about 50p. and a true specific gravity of about 1.53) was used.
  • metalmy made by Toyo Rayon Co., Ltd. (hereinafter referred to simply as metalmy") comprising a polyethylene terephthalate film having a thickness of 100p. (hereinafter referred to simply as PET film”) and an aluminium layer evaporated on one surface of the film was used.
  • PET film polyethylene terephthalate film having a thickness of 100p.
  • the EPM photoner was uniformly applied on the PET film side of the metalmy.”
  • the amount of photoner applied on the substrate was varied from 70 to 140g/m
  • the voltage of the DC corona charging was varied from -3 to 6KV.
  • the height of the corona charger (the distance from the layer of the EPM photoner) was 2 to 3cm.
  • the surface voltage of the charged layer of the EPM photoner" was l to 400 volts.
  • the surface of the EPM photoner layer which had been charged as described above was exposed to imagewise light of I00 to l000 lux sec illumination. Then, the surface of the EPM photoner was subject to A.C. corona charging.
  • the A.C. corona charger was impressed with alternating current of 3KV.
  • the A.C. corona charger was controlled to generate the same amount of positive and negative ions.
  • the image was developed by air blow.
  • the air blow speed was controlled to be 10 to ZOm/sec on the substrate.
  • the test was performed under the above-described conditions with and without a bias voltage.
  • EXAMPLE ll As the insulating substrate, a PET film having a thickness of l25u, a vinyl chloride plate having a thickness of l to 2mm, an acryl plate having a thickness of l to 2mm and other high molecular insulating materials as well as insulating films such as vinyl chloride and polystyrene having a thickness of 200p. and other insulating material having a thickness of p. to 2mm were used, and the first embodiment of the invention was carried out for testing the invention with these materials. As for the photoconductive particles, EPM photoner was used as in Example I.
  • Each of the above insulating substrates was in turn put into contact with a metal plate serving as a grounded electrode. After photoconductive particles had been applied thereon, D.C. charging, exposure, A.C. corona charging and development were performed under the same conditions as those in Example I. At the time of development, a bias voltage of 50 to lKV/cm was used.
  • EXAMPLE III The exposure to the imagewise light and DC. charging were simultaneously performed in accordance with the second embodiment of the invention.
  • EPM photoner As the photoconductive particles, EPM photoner" was used as in Example I. Further, as the insulating substrate, metalmy was used as in Example I. The scattering or application of the EPM photoner on the substrate, exposure and DC. charging and A.C. charging were conducted under the same conditions as those in Example I.
  • the electrostatic latent image which was formed by the above process was developed into a visible image by use of air blow. The air blow speed was set to l5 to 20m/sec on the substrate. The bias voltage was varied from 0 to 30OV/cmv In each case, an excellent particle image of high contrast was obtained.
  • EXAMPLE IV The exposure to the imagewise light and DC. charging were simultaneously performed in accordance with the second embodiment of the invention, and the insulating materials used in Example II were used. Further, the insulating material was used in contact with a metal plate serving as a grounded electrode. As the photoconductive particles, EPM photoner" was used as in Example II. The application of the EPM photoner" on the substrate, the exposure, D.,C. corona charging, and
  • Example 1 1 development were performed under the same conditions as those employed in Example Ill.
  • the bias voltage was changed from 100 to lKV/cm. In each case a fairly good image of high contrast was obtained.
  • EXAMPLE V In accordance with the third embodiment of the invention, D.C. charging was applied to the whole layer of photoconductive particles and the exposure to the imagewise light and the A.C. corona charging were performed simultaneously.
  • EPM photoner As the photoconductive particles, EPM photoner" was used. The application of the photoner on the substrate, exposure, and A.C. corona charging were made under the same conditions as those employed in Exampe l. The surface potential of the EPM photoner scattered after precharging was 300 to 500 volts.
  • the insulating substrate the same materials as those used in Examples l and II were used. Insulating materials other than metalmy" were used in contact with a grounded metal plate. The speed of the air blow was varied from 14 to 22m/sec. The bias voltage was varied from to 300V/cm in case of the metalmy and from 100 to 700V/cm for other materials.
  • EXAMPLE VI Similarly to Example V, particle images were formed on a conductive substrate in accordance with the third embodiment of the invention.
  • the conductive substrate metal, paper containing an appropriate degree of moisture and other conductive materials were used. The surface resistance of these materials was not higher than IOK'L.
  • the photoconductive particles EPM photoner" was used as in the other examples.
  • the application of the particles on the substrate, D.C. charging, and development were conducted under the same conditions as employed in Example V.
  • the A.C. corona charging was performed with a voltage of 0 to 2KV. A bias voltage was not used.
  • EXAMPLE VII The test was performed in accordance with the third embodiment of the invention as in Example V.
  • the substrate materials having a surface resistance of l0 to l0"-'! and a thickness of 100p. to 1 mm were used. Resistances of this degree fall in the intermediate range between insulator and conductor.
  • EPM photoner As the photoconductive particles, EPM photoner" was used.
  • the application of photoner on the surface of the substrate, D.C. charging, exposure and AC. corona charging were conducted under the same conditions as those employed in Exampe VI. The conditions of development were also the same as those employed in Example VI.
  • the substrates were used in contact with a metal plate which was grounded. The bias voltage was changed from 100 to 7OOV/cm.
  • EXAMPLE VIII Similarly to Example V, the test was conducted in accordance with the third embodiment of the invention.
  • a metal plate As the substrate, a metal plate was used. The metal plate was partially covered with an insulating high molecular coating having a surface resistance of 10 or more. Further. another portion of the metal plate was covered with a coating containing graft carbon in styrenated alkyd resin having a surface resistance of 10'" to IO Q. The thickness of these coatings was 10 to lSu. Thus. three different parts were formed on a metal substrate, an insulating part, a non-coated conductive part and an insulating-conductive part.
  • EXAMPLE IX The test was performed without a conductive base in accordance with the fourth embodiment.
  • the photoconductive particles were scattered on the surface of an insulating substrate and a DC. charger and an AC. charger were used on the backside of the substrate to form an image in accordance with the fourth embodiment of the invention.
  • the conditions of formation of the image were made the same as those employed in the foregoing Examples 1 to VIII.
  • a DC. voltage of 6KV was impressed and in the second charging with the AC. charger, an AC. voltage of 3KV was impressed.
  • a bias voltage of lOO to 600V/cm was used.
  • a process for making an electrophotographic image by use of photoconductive particles comprising the steps of:
  • a process for making an electrophotographic image comprising the steps of providing a plurality of layers of charged photoconductive particles on a substrate;
  • a process for making an electrophotographic image as defined in claim 10 wherein said step of providing a plurality of layers of charged photoconductive particles on a recording medium comprises charging a number of photoconductive particles in a predetermined polarity, and applying the charged particles in a plurality of layers on a recording medium.
  • a process for making an electrophotographic image comprising the steps of providing a plurality of layers of photoconductive particles on a substrate;

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  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Electrophotography Using Other Than Carlson'S Method (AREA)
  • Combination Of More Than One Step In Electrophotography (AREA)
US453421A 1973-05-07 1974-03-21 Process for making an electrophotographic image by use of photoconductive particles Expired - Lifetime US3926627A (en)

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JP48050428A JPS502547A (enrdf_load_stackoverflow) 1973-05-07 1973-05-07

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JP (1) JPS502547A (enrdf_load_stackoverflow)
GB (1) GB1436526A (enrdf_load_stackoverflow)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4075011A (en) * 1973-12-12 1978-02-21 Fuji Photo Film Co., Ltd. Electrostatic powder coating method
US4309498A (en) * 1978-03-23 1982-01-05 Hitachi Metals, Ltd. Electrophotography using a magnetic brush
EP0165319A4 (en) * 1983-11-30 1987-11-09 Matsushita Electric Ind Co Ltd METHOD FOR REPRESENTING AN IMAGE.
US5194352A (en) * 1989-03-17 1993-03-16 Dai Nippon Printing Co., Ltd. Method for toner development of electrostatic latent image and for formation of toner image in which a specified gap is maintained between a photosensitive member and an electrostatic information recording medium

Families Citing this family (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS4923966A (enrdf_load_stackoverflow) * 1972-07-03 1974-03-02
JPS4989356A (enrdf_load_stackoverflow) * 1972-12-29 1974-08-27
JPS50103181A (enrdf_load_stackoverflow) * 1974-01-24 1975-08-14
JPS5342467A (en) * 1976-09-29 1978-04-17 Nakano Sougiyou Kk Excrements incineration method and apparatus
JPS5382066A (en) * 1976-12-27 1978-07-20 Nittetsu Kakoki Kk Incineration method for concentrated waste water
JPS5595029U (enrdf_load_stackoverflow) * 1978-12-20 1980-07-01
CN103117114B (zh) * 2013-02-21 2016-07-06 罗志昭 一种铜与铝合金配合使用方法

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2924519A (en) * 1957-12-27 1960-02-09 Ibm Machine and method for reproducing images with photoconductive ink
US3737311A (en) * 1971-06-04 1973-06-05 Xerox Corp Electrostatic particle transfer imaging process
US3775103A (en) * 1967-02-13 1973-11-27 Fuji Photo Film Co Ltd Electrophotographic material and process for producing same
US3825421A (en) * 1970-10-29 1974-07-23 Fuji Photo Film Co Ltd Process for forming an image on insulative materials
US3833365A (en) * 1972-06-26 1974-09-03 Fuji Photo Film Co Ltd Electrostatic power coating method combined with an electrophotographic process

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2924519A (en) * 1957-12-27 1960-02-09 Ibm Machine and method for reproducing images with photoconductive ink
US3775103A (en) * 1967-02-13 1973-11-27 Fuji Photo Film Co Ltd Electrophotographic material and process for producing same
US3825421A (en) * 1970-10-29 1974-07-23 Fuji Photo Film Co Ltd Process for forming an image on insulative materials
US3737311A (en) * 1971-06-04 1973-06-05 Xerox Corp Electrostatic particle transfer imaging process
US3833365A (en) * 1972-06-26 1974-09-03 Fuji Photo Film Co Ltd Electrostatic power coating method combined with an electrophotographic process

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4075011A (en) * 1973-12-12 1978-02-21 Fuji Photo Film Co., Ltd. Electrostatic powder coating method
US4309498A (en) * 1978-03-23 1982-01-05 Hitachi Metals, Ltd. Electrophotography using a magnetic brush
EP0165319A4 (en) * 1983-11-30 1987-11-09 Matsushita Electric Ind Co Ltd METHOD FOR REPRESENTING AN IMAGE.
US5194352A (en) * 1989-03-17 1993-03-16 Dai Nippon Printing Co., Ltd. Method for toner development of electrostatic latent image and for formation of toner image in which a specified gap is maintained between a photosensitive member and an electrostatic information recording medium

Also Published As

Publication number Publication date
GB1436526A (en) 1976-05-19
DE2421510A1 (de) 1974-11-14
JPS502547A (enrdf_load_stackoverflow) 1975-01-11
DE2421510B2 (de) 1976-11-25

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