Abstract: An electrophotographic photoreceptor comprising an electrically conductive substrate and a photoconductive layer formed thereon, wherein said photoconductive layer contains a compound of the formula ( I ): ##STR1## wherein R.sup.1 to R.sup.18 are respectively and independently a hydrogen atom, a halogen atom, a saturated or unsaturated aliphatic hydrocarbon group, an aromatic hydrocarbon group, an alkoxy group, an aryloxy group, a dialkylamino group or a diarylamino group, wherein the aliphatic hydrocarbon group, the aromatic hydrocarbon group, the alkoxy group, the aryloxy group, the dialkylamino group and the diarylamino group may have substituents, X is a bivalent hydrocarbon group which may have substituents, each of A.sup.1 and A.sup.2 is a saturated or unsaturated aliphatic hydrocarbon group or an aromatic hydrocarbon group, or is bonded to R.sup.5 or R.sup.

Abstract: An electrophotographic photoreceptor comprising an electrically conductive support and a photosensitive layer formed thereon, wherein said photosensitive layer contains at least one member selected from the group consisting of hydrazone compounds of the formulas (I), (II) and (III): ##STR1## wherein X is a hydrogen atom or a group of the formula (IV):--C(R.sup.8).dbd.N--Q.sup.2 (IV)Q.sup.1 is a group of the formula (V), (VI), (VII), (VIII) or (IX); Q.sup.2 is a group of the formula (VI), (VII), (VIII), (IX) or (X); each of Q.sup.3 and Q.sup.

Abstract: A process for the preparation of crystalline oxytitanium phthalocyanine showing a distinct diffraction in peak at a Bragg angle (2.theta..+-.0.2.degree.) of 27.3.degree. in the X-ray diffraction spectrum, which comprises mechanically pulverizing oxytitanium phthalocyanine, dispersing it in water to form a suspension, adding an organic solvent into the suspension and heating the suspension.

Abstract: Disclosed herein is an electrophotographic photoreceptor having on a conductive base at least one charge generation layer and at least one charge transfer layer, which comprises a sulfonate ester compound represented by the general formula (I): ##STR1## wherein R.sup.1, R.sup.2, R.sup.3, R.sup.4 and R.sup.5 are independently hydrogen atom, halogen atom, cyano group, nitro group or alkyl group; R.sup.6, R.sup.7, R.sup.8 and R.sup.9 are independently hydrogen atom or halogen atom; and X is cyano group, alkoxycarbonyl group, optionally substituted aryloxycarbonyl group or optionally substituted aryl group, in the charge transfer layer. The electrophotographic photoreceptor according to the present invention has the excellent durability.