Abstract: Disclosed are a phthalocyanine composition suitable for use in an electrophotographic photoreceptor that exhibits a high charge potential and a high sensitivity and which exhibits stable performances without causing a change in various properties in repeated use, a process for the production thereof, and an electrophotographic photoreceptor to which the above phthalocyanine composition is applied. The present invention provides a phthalocyanine composition comprising a oxytitanium phthalocyanine and a metal-free phthalocyanine and having a crystal form having peaks at Bragg angles (2&thgr;±0.2°) of 7.0°, 9.0°, 14.1°, 18.0°, 23.7° and 27.3°, and having no peak at a Bragg angle (2&thgr;±0.2°) of 9.5°, in CuK&agr; 1.

Abstract: Disclosed are a phthalocyanine composition having main diffraction peaks at 7.0°, 9.0°, 14.1°, 18.0°, 23.7° and 27.3° of Bragg angles (2&thgr;±0.2°) in an X-ray diffraction spectrum with Cu K&agr;, a process for producing the same and an electrophotographic photoreceptor using the same.

Abstract: Disclosed are a phthalocyanine composition suitable for use in an electrophotographic photoreceptor that exhibits a high charge potential and a high sensitivity and which exhibits stable performances without causing a change in various properties in repeated use, a process for the production thereof, and an electrophotographic photoreceptor to which the above phthalocyanine composition is applied.

Abstract: Oxytitanium phthalocyanine having a novel crystal form having excellent electrophotographic properties, such as a high charge potential, a high sensitivity and stable performances free from causing changes in various properties in repeated use, can be produced in the absence of a halogen substance, by carrying out the crystal transformation of amorphous oxytitanium phthalocyanine in a solvent comprising water and naphthalene.

Abstract: The present invention provides an electrophotographic photoreceptor which comprises an electrically conductive support and a light-sensitive layer which contains an azo pigment represented by the following formula (I): ##STR1## wherein R.sub.1 represents an unsubstituted or substituted alkyl or alkoxy group having 3 to 8 carbon atoms, R.sub.2 represents a hydrogen atom, a halogen atom or an unsubstituted or substituted alkyl or alkoxy group having 1 to 3 carbon atoms and m and n each represent 1 or 2.

Abstract: Disclosed is a double-layered type electrophotographic photoreceptor which comprises an electroconductive support and a carrier generation layer containing a pigment or a dye as a carrier generation material and a carrier transport layer which are provided on said support, wherein the carrier transport layer contains an organic low molecular weight carrier transport material, a binder resin, a hydroquinone compound represented by the following formula (II): ##STR1## wherein R.sup.7, R.sup.8, R.sup.9 and R.sup.10 each represents a hydrogen atom, a halogen atom, an alkyl group, an aryl group, an alkoxy group, a carbamoyl group or an alkylthio group, and a compound represented by the following formula (III): ##STR2## wherein R.sup.11, R.sup.12, R.sup.13 and R.sup.14 each represents a hydrogen atom, a hydroxyl group, an alkyl group or an alkoxy group with a proviso that at least one of R.sup.11 -R.sup.14 is hydroxyl group, R.sup.15 and R.sup.

Abstract: Disclosed is an electrophotographic photoreceptor which is high in sensitivity and endurance and which comprises an electroconductive support and, provided thereon, a photosensitive layer which contains a hydrozone compound represented by the following formula [I], [II], or [III]: ##STR1## wherein the various subgroups designated by R or A are as described in the specification.

Abstract: This invention provides an electrophotographic photoreceptor which is high in durability and high in sensitivity. This photoreceptor comprises an electroconductive support and, provided thereon, a photosensitive layer containing an azo pigment represented by the following formula [I] or [II]: ##STR1## wherein A represents a hydrogen atom, an alkyl group, a phenyl group or a heterocyclic ring group, m and n each represents 0 or 1, X represents a hydrogen atom, a lower alkyl group, a cyano group or a halogen atom and Cp represents a coupler residue, or ##STR2## wherein Z represents an alkyl group, a phenyl group or a heterocyclic ring group, X represents a hydrogen atom, a lower alkyl group, a cyano group or a halogen atom and Cp represents a coupler residue.

Abstract: Disclosed is an electrophotographic photoreceptor which is high is sensitivity and high in endurance and which contains in photosensitive layer a novel stilbene compound represented by the following formulas [I], [II], or [III]: ##STR1##

Abstract: This invention provides an electrophotographic photoreceptor which is high in durability and high in sensitivity. This photoreceptor comprises an electroconductive support and, provided thereon, a photosensitive layer containing an azo pigment represented by the following formula [I] or [II]: ##STR1## wherein A represents a hydrogen atom, an alkyl group, a phenyl group or a heterocyclic ring group, m and n each represents 0 or 1, X represents a hydrogen atom, a lower alkyl group, a cyano group or a halogen atom and Cp represents a coupler residue, or ##STR2## wherein Z represents an alkyl group, a phenyl group or a heterocyclic ring group, X represents a hydrogen atom, a lower alkyl group, a cyano group or a halogen atom and Cp represents a coupler residue.