Abstract: The present invention provides photoconductive paints which have excellent dispersability and dispersion stability and which allow formation of coatings with high coating strength and excellent smoothness.The invention relates to photoconductive paint composed primarily of an inorganic photoconductive material and a binding resin formed on a conductive substrate, wherein the binding resin contains compound fine particles (A) and a resin (B) as defined below, in a solid weight ratio of compound fine particles (A)/resin (B) in the range of 0.5/9.5-4.0/6.0.The compound fine particles (A) have an organic polymer bound to surfaces of inorganic fine particles, and the resin (B) is a resin composition obtained by polymerizing an acrylic monomer mixture, the resin having an acid value of 2.0-12.0.

Abstract: A laser-sensitive electrophotographic lithograph printing plate material having excellent sensitivity to light having a long wavelength of from 700 to 1000 nm, a high thermal resistance and persistency, and high resistance to a change of sensitivity with time, provided with a laser-sensitive photoconductive layer formed on a substrate and comprising a photoconductive pigment; a sensitizing dye comprising at least one compound of the formula (I): ##STR1## wherein R.sup.1 and R.sup.2 are respectively --CH.sub.3, --C.sub.2 H.sub.5, or --CH.sub.2 --CH.dbd.CH.sub.2 and X is a halogen atom, an antioxidant comprising at least one member selected from radical chain terminators, peroxide-decomposing agents, and heavy metal-deactivating agents, and an electrically insulating binder.

Abstract: A lithographic plate blank for imaging on a laser printer comprises a sheet of flexible electrically non-conductive material and an image receiving etchable layer coating bonded on a surface thereof, the coating including zinc oxide, a resin binder, and an electrical property regulating agent and being effective to provide the plate with a surface resistance of between 10.sup.11 and 10.sup.14 ohms per square and a dark decay rate of at least 15 volts per second. A method of preparation of a blank plate and a method of preparation of an imaged plate are disclosed.

Abstract: A lithographic printing plate precursor excellent in oil-desensitivity, whereby an original is faithfully reproduced without occurrence of overall or spotted stains as an offset master is provided, which comprises an electrically conductive support and at least one photoconductive layer, provided thereon, containing photoconductive zinc oxide and a binder resin, in which said photoconductive layer contains hydrophilic resin grains having an average grain diameter of same as or smaller than the maximum grain diameter of said photoconductive zinc oxide grains, and said binder resin contains at least one of Resin A having a weight average molecular weight of 1.times.10.sup.3 to 2.times.10.sup.4 and Resin B having a weight average molecular weight of at least 3.times.10.sup.4.

Abstract: An electrophotographic lithographic printing plate precursor capable of giving a good image free from pinholes is provided which comprises an electrically conductive base coated, on one side thereof, with an undercoated layer and a photoconductive layer containing zinc oxide as a predominant component in order and on the opposite side thereof, with a back layer, said undercoated layer having a surface resistivity of 1.times.10.sup.8 to 1.times.10.sup.14 .OMEGA. and said back layer having a surface resistivity of at most 1.times.10.sup.10 .OMEGA..

Abstract: An electrophotographic material having an enhanced sensitivity to laser rays comprises,(A) an electroconductive substrate, and(B) a laser-sensitive electrophotographic layer comprising (a) a finely divided photoconductive zinc oxide, (b) a resinous binder, (c) a sensitizing coloring material comprising at least one member selected from the compounds of the formulae (I) and (II): ##STR1## in which m.sup.1, m.sup.2, n.sup.1 and n.sup.2 are 1 to 8, R.sup.1 and R.sup.2 are --COO or --SO.sub.3, R.sup.3 and R.sup.4 are H, --CH.dbd.CH.sub.2 --COOH, --SO.sub.3 H, --COONa, --SO.sub.3 Na, COOK or --SO.sub.3 K, X is Cl, Br, I or --ClO.sub.4, ##STR2## and, (d) a sensitizing assistant comprising at least one carboxylic anhydride of the formula (III): ##STR3## wherein R.sup.5 and R.sup.6 are H, C.sub.1-8 alkyl or phenyl.

Abstract: A persistent conductivity-type electrophotographic recording member comprising a nonconductive layer and a photoconductive layer disposed on one surface of the nonconductive layer, wherein the photoconductive layer comprises a photosensitive material substantially uniformly dispersed in a binder which consists essentially of a copolymer of styrene with at least one alkyl acrylate, the alkyl group of which comprises from four to twelve carbon atoms. The acid value of such copolymers is typically preferably below about 2, and more preferably below about 1.

Abstract: The present invention relates to a lithographic printing plate which can eliminate disadvantages of conventional zinc oxide master papers and has sensitivity sufficient for practical use in respect of long wavelength laser light. The invention contemplates to provide the lithographic printing plate which is fabricated by charging an electrophotographic plate involving a photoconductive layer on a conductive substrate, the photoconductive layer being prepared by dispersing a mixture containing 50 wt % or less of a phthalocyanine pigment/(zinc oxide and zinc sulfide) into a binder resin, exposing the electrophotographic plate to an image to form the electrostatic latent image, developing the exposed electrophotographic plate by the use of an ink receptive toner, and fixing the plate thus developed.

Abstract: Electrophotographic photosensitive element using zinc oxide in a photosensitive layer thereof formed in conductive support are described. Zinc oxide is used in combination with polycarbonate binder and a compound of the specific type. The compound is represented by the formula ##STR1## in which R.sub.1, R.sub.2, R.sub.3 and R.sub.4 independently represent a hydrogen atom, a substituted or unsubstituted alkyl group, a cycloalkyl group, an alkenyl group, or an aryl group, R.sub.5 and R.sub.6 independently represent a hydrogen atom, a substituted or unsubstituted alkyl group, a cycloalkyl group, an alkenyl group, a cycloalkenyl group, or an aryl group, R.sub.7, R.sub.8, R.sub.9 and R.sub.10 independently represent a hydrogen atom, a hydroxyl group, a substituted or unsubstituted alkyl group, a cycloalkyl group, an alkenyl group, an aryl group, an alkoxy group or an amino group. Optionally, R.sub.5 and R.sub.6 may jointly form a saturated or unsaturated hydrocarbon ring having from 3 to 10 carbon atoms.

Abstract: Electrophotographic photosensitive material comprising an electroconductive substrate and a layer of a photoconductive composition composed of a dispersion of a charge generating pigment in a charge transporting medium, which is formed on the electroconductive substrate, wherein said photoconductive composition contains an N,N-di-substituted-carbamic acid salt in an amount of 20 to 200% by weight based on the charge generating pigment. This electrophotographic electrophotosensitive material has excellent ozone resistance and shows a high initial charge retention ratio and sensitivity retention ratio when the cycle of charging and light exposure is repeated many times.

Abstract: An etchable electrophotographic printing plate comprising a coating on a surface of an electroconductive support such as grained, anodized aluminum of effective amounts of photoconductive ZnO and of a sensitizing dye dispersed in an organic resin binder comprised of about 60-90 wt. % of C.sub.2 -C.sub.4 alkenyl C.sub.2 -C.sub.8 alkanoate, about 5-30 wt. % of di(C.sub.1 -C.sub.8 alkyl) C.sub.4 -C.sub.8 alkenedionate, about 2-8 wt. % of C.sub.3 -C.sub.8 alkenoic acid or C.sub.4 -C.sub.8 alkenedioic acid, and about 0.5-5.0 wt. % of a cross-linking agent. The preferred thermally cross-linkable organic resin binder is a random copolymer of 70 wt. % vinyl acetate, 24 wt. % dibutyl maleate; 5 wt. % acrylic acid and 1 wt. % glycidyl methacrylate. The etchable printing plate of the present invention is environmentally safe, has excellent shelf life and high sensitivity to actinic radiation.

Abstract: The electrophotographic photosensitive member has a photoconductive layer containing photoconductive particles each of which has a water insoluble compound of a metal element of Group VIII of the Periodic Table deposited on the surface.

Abstract: In an electrostatic photographic process comprising subjecting an electrostatic photographic photosensitive plate to the combination of negative charging, positive charging and imagewise exposure to form an electrostatic latent image of a positive polarity, said electrostatic photographic photosensitive plate having such charging characteristics that a photosensitive layer can be positively charged by sequential negative corona charging and positive corona charging and positive charging is rendered substantially impossible by irradiation with light, and then subjecting the so treated photosensitive plate to positive charging a predetermined number of times, whereby an electrostatic latent image is formed the predetermined number of times by imagewise exposure conducted once, if a zinc oxide-resin dispersion is used for the photosensitive layer of the photosensitive plate and predetermined amounts of a triphenylmethane basic dye and a silicone oil are incorporated in the photosensitive layer, the time required

Abstract: An electrophotographic photoconductor, formed on a conductive substrate by spray pyrolysis, comprising essentially a major amount of cadmium sulphide and a minor amount of zinc sulphide. The cadmium layer is at least three microns in thickness and is formed in three zones. The zone adjacent the metal substrate, adapted to form a contact layer, bears an amount of lead sulphide; the outermost zone, adapted to absorb light, is doped with a minor amount of copper to eliminate fatigue; and the intermediate zone, which is necessary to increase the surface potential, is adapted to transport light-generated charge and is doped with a minor amount of chlorine. The process is carried on in the atmosphere with three different aqueous solutions of reagents to form the three different zones. The photoconductive layer is microcrystalline in structure and bears adsorbed oxygen.

Abstract: Improvement in the humidity resistance of photoconductive cadmium sulfoselenide (CdSSe) is achieved by soaking commercially available CdSSe in a solution of vinylidene chloride-acrylonitrile copolymer in an organic solvent, followed by removing the excessive solution and then heating the soaked photoconductive material.

Abstract: A photoconductive material of a fine crystal of a cadmium sulfide-type photoconductive compound, on the surface of the crystal a film-forming compound having a dehydrating function such as an isocyanate compound is deposited. The photoconductive material is employed for forming an electrophotographic material or a photo-cell.

Abstract: A sensitizing dye and a hydrophilic resin are dissolved in a first solvent, and a second solvent is added to the solution. The second solvent is less volatile than the first solvent, miscible therewith and does not dissolve both of the sensitizing dye and the hydrophilic resin. A powder of the sensitized zinc oxide is incorporated into the solution. After blending, the mixture is dried and pulverized to obtain a powder of sensitized zinc oxide. This powder is then mixed with a bonding agent consisting of a resinous material having an acid value of 5-30 to form a mixture which is formed into a thin photosensitive layer for use in electrophotography.

Abstract: An electrophotographic element having a conductive support upon which a coating of oleophilic resin-encapsulated zinc oxide particles, and a sensitizer dispersed in a binder containing vinyl chloride and vinyl acetate polymers is disclosed. Capsule wall can be 5A to 1.mu. thick. The oleophilic resin can be silicone, urethane, epoxy.

Abstract: An electrophotographic recording material comprising a photoconductive layer incorporating photoconductive zinc oxide in the presence of a compound within the scope of the following general formula:R--SHwherein: R represents (1) an unsubstituted aliphatic hydrocarbon group containing at least 5 carbon atoms or (2) an aliphatic hydrocarbon group substituted with a --COOQ group wherein Q is an organometallic group or an aliphatic hydrocarbon group, containing at least 5 carbon atoms, or (3) an aliphatic hydrocarbon group substituted with a --COOH group and containing at least two methylene groups between the --COOH group and the --SH group, and said general formula including the modification wherein the hydrogen atom of the --SH group is substituted to form an organometal mercaptide.The above compound improves the charge retention of the photoconductive layer, i.e. lowers its dark-decay, under conditions of high relative humidity.

Abstract: An electrophotographic photoreceptor has a photoconductive layer on a substrate. The photoconductive layer comprises a photoconductor and a water-soluble compound which reacts with free anion released from the photoconductor to produce an unsoluble salt and contains anion having smaller equivalent ionic conductance than that of the free anion.

Abstract: Electrophotographic members prepared by coating a paper or film with a slurry of photoconductive metal-compound particles, e.g., zinc oxide particles, dispersed in a liquid vehicle containing a solution of resinous binder having carboxyl groups. Viscosity of the coating slurry is controlled and/or stabilized by incorporating into the slurry a viscosity stabilizing agent comprising a chelate precursor which forms with the binder a chelating agent having the property of complexing metal ions, e.g., zinc ions, by formation of a ring structure incorporating the metal ion. Suitable viscosity stabilizing agents include: ethylenediamine, diethylenetriamine, and ethylenediaminetetraacetic acid and its salts.

Abstract: A sintered high sensitive electrophotographic plate free of cracks in a photoconductive layer and exfoliation of it from a substrate can be obtained by adding an inorganic material, whose melting or softening temperature is higher than a firing temperature, into a mixture composed essentially of photoconductive material and a glass binder having a softening temperature lower than the firing temperature.

Abstract: The duration of use of spectrally sensitized pigment bonding agent layers which are to be used a number of times is substantially increased by performing floodlighting, after the development and/or transfer and prior to the recharging, with a light which is suitable per se for the image formation, but which is substantially not absorbed by the dye.