Abstract: An electrophotographic photoreceptor having a bipolar charge transport layer with a hole-transporting property and an electron-transporting property, the bipolar charge transport layer containing a block copolymer or a graft copolymer, and a process cartridge and an electrophotographic apparatus using the electrophotographic photoreceptor. The electrophotographic photoreceptor has a high performance and a long life and can provide various properties required for a photoreceptor by forming, the bipolar charge transport layer which is excellent in hole- and electron-transporting properties, mechanical strengths, a discharge product resistance and a coating dispersion stability, and the process cartridge and the electrophotographic apparatus using the electrophotographic photoreceptor can provide a high performance and a high durability.

Abstract: A resistive element is produced by forming a substrate glazed with glass, printing or coating a resistive element-forming paste onto the substrate, calcining the paste in a first heating step to form an element comprising a film on the substrate and subjecting the resulting element to a heat treatment in a second heating step to diffuse an amount of glass into the film to increase resistivity of the element.

Abstract: A charge transporting block and an insulating block are block copolymerized or graft copolymerized to form a charge transporting copolymer. The charge transporting polymers may be used in an electrophotographic photoreceptor and an electrophotographic device.

Abstract: Hydroxygallium phthalocyanine crystals and an electrophotographic photoreceptor comprising the same. The hydroxygallium phthalocyanine crystals contain at least one of a polar organic solvent selected from the group consisting of a compound having an amido group, a compound having a sulfoxide group, and an organic amine.

Abstract: An excellent electrographic photosensitive member having a high sensitivity, a high chargeability and a low residual potential. The electrographic photosensitive member comprises a photosensitive layer, or a photosensitive layer and an underlayer superimposed over an electroconductive support, wherein the photosensitive layer and/or the underlayer contain a chlorogallium phthalocyanine which is substituted with an electron-withdrawing group and has the following formula: ##STR1## where X represents an electron-withdrawing group such as a halogen atom and n is an integer of 2 to 4.

Abstract: Hydroxygallium phthalocyanine crystals having intense diffraction peaks at Bragg angles (2.theta..+-.0.2.degree.) of 7.5.degree., 9.9.degree., 12.5.degree., 16.3.degree., 18.6.degree., 25.1.degree. and 28.3.degree. in Cuk.alpha. characteristic X-ray diffractometry, a process for producing the same, and an electrophotographic photoreceptor containing the same are disclosed. The hydroxygallium phthalocyanine crystals are obtained by once preparing impurity-free hydroxygallium phthalocyanine having intense X-ray diffraction peaks at specific Bragg angles, followed by a solvent treatment for crystal transformation, in which the impurity-free crystals are prepared by using excess phthalocyanine ring-forming compound in the synthesis of starting gallium phthalocyanine or by removing insoluble matter from the acid paste of starting gallium phthalocyanine.

Abstract: Hydroxygallium phthalocyanine crystals having intense diffraction peaks at Bragg angles (2.theta..+-.0.2.degree.) of 7.5.degree., 9.9.degree., 12.5.degree., 16.3.degree., 18.6.degree., 25.1.degree. and 28.3.degree. in CuK.alpha. characteristic X-ray diffractometry, a process for producing the same, and an electrophotographic photoreceptor containing the same are disclosed. The hydroxygallium phthalocyanine crystals are obtained by once preparing impurity-free hydroxygallium phthalocyanine having intense X-ray diffraction peaks at specific Bragg angles, followed by a solvent treatment for crystal transformation, in which the impurity-free crystals are prepared by using excess phthalocyanine ring-forming compound in the synthesis of starting gallium phthalocyanine or by removing insoluble matter from the acid paste of starting gallium phthalocyanine.

Abstract: A resistive element film-forming paste includes (1) an organic metal compound, (2) at least one organic non-metal additive, and (3) a solution of asphalt in a solvent. A resistive element is formed by coating the paste on a substrate followed by calcining.

Abstract: A process for producing a tungsten oxide film which comprises the steps of: reacting a tungstate with a salt of an organic compound represented by formula (I) to obtain a tungstic acid compound; mixing the tungstic acid compound with an organic solvent to prepare a composition; and removing an organic substance and the solvent from the composition:R.sub.1 R.sub.2 R.sub.3 NH.sup.+ X.sup.- (I)wherein R.sub.1, R.sub.2, and R.sub.3 each represents a hydrogen atom or a saturated or unsaturated hydrocarbon group having from 1 to 20 carbon atoms, and X.sup.- represents a halogen atom. A tungsten oxide film obtained by the above-described process and an electrochromic device comprising the tungsten oxide film.

Abstract: A resistive film-forming composition to be coated on a substrate and calcined to form a resistive film is disclosed, which contains an organic iridium compound selected from a compound represented by formula (I): ##STR1## wherein R.sup.1 represents a hydrogen atom, an alkyl group, or an alkoxy group, a compound represented by formula (II):Ir(R.sup.4 COCR.sup.3 COR.sup.5).sub.3wherein R.sup.3 represents a hydrogen atom or an alkyl group; and R.sup.4 and R.sup.5 each represent an alkyl group. A uniform resistive film having excellent electrical characteristics can be formed with good adhesion to a substrate.