Abstract: A developing device includes a device body which has a toner reception port and supplies toner stored therein to a photosensitive member, a toner cartridge, which is detachably mounted in the device body in coincidence with the toner reception port, has a toner discharge port opposed to the toner reception port, and supplies toner stored therein to the device body through the ports, a sealing member which is mounted on the device body to surround the toner reception port and seals between the device body and the toner cartridge mounted in the device body, and a pressing mechanism which is provided on the toner cartridge and presses the toner cartridge on the sealing member when the toner cartridge is mounted in the device body.

Abstract: An electrophotographic photoreceptor comprising a support having thereon a photosensitive layer, in which said photosensitive layer contains a butadiene compound represented by the following general formula: ##STR1## wherein each of A.sub.1 -A.sub.4, which may be the same or different, is an alkyl group, a hydrazone compound represented by the following general formula [II]: ##STR2## wherein each of B.sub.1 and B.sub.2, which may be the same or different, is an alkyl group, a phenyl group, a benzyl group or a methoxyphenyl group, R.sub.1 is hydrogen, an alkyl group or O-R in which R is a straight-chain or branched alkyl, alkenyl or alkadienyl group having from 5 to 10 carbon atoms or an aralkyl group having from 7 to 10 carbon atoms, and R.sub.2 is an alkyl group, a phenyl group, a methoxy group, an ethoxy group, a benzyl group, a methoxyphenyl group, a tolyl group or a naphtyl group, and a monophenol compound.

Abstract: An electrophotographic apparatus has its electrophotographic component parts divided into three units consisting essentially of a developing unit A, a photoreceptor unit B and a toner cartridge unit C. Each of the units is capable of being detached from and reattached to the main body of the apparatus while maintaining the required relative positions. The service lives of the units are set in such a manner that the ratio therebetween is represented as a ratio between integers, and the relationship therebetween in magnitude satisfies the relationship of the service life of the developing unit A.gtoreq.the service life of the photoreceptor unit B.gtoreq.the service life of the toner cartridge unit C. Thus, the apparatus enables its maintenance to be performed easily and economically without requiring any increase in the size and the cost of the electrophotographic mechanisms.

Abstract: An electrophotographic photoreceptor comprises a photoconductive layer having a protective layer disposed thereon, said protective layer being formed by dehydrocondensation of the hydrolyzate of a perfluoroalkyl silane coupling agent, or the hydrolyzate of a mixture of a perfluoroalkyl silane coupling agent and a silane coupling agent. The photoreceptor is very useful in that it can exhibit a high performance even in an environment at a higher temperature and at a higher humidity and that it has a high resistance to the abrasion with a great number of sheets being printed and with the cleaning members and that it is capable of preserving a high resolution without any image blurring.

Abstract: An electrophotographic photoreceptor comprises an electrically conductive support, a photoconductive layer provided thereon, and a protective layer coated on the photoconductive layer, wherein the protective layer comprises a product of uncatalized hydrolysis of a composition essentially consisting of at least one specific epoxysilane compound, at least one specific alkylalkoxysilane compound, and at least one specific aminosilane compound. The photoreceptor is very useful in that it is free from wear due to friction with paper and cleaning members, keeps high resolving power, and is sufficiently proof against continuous copying under conditions of high temperature and high humidity.

Abstract: An electrophotographic photoreceptor having a photosensitive layer containing a butadiene compound represented by general formula ##STR1## wherein A.sub.1 to A.sub.4 are alkyl group, and a hydrazone compound represented by general formula ##STR2## wherein B.sub.1 and B.sub.2 are alkyl, phenyl, benzyl or methoxyphenyl groups, R.sub.1 is hydrogen, alkyl, alkoxy or benzyloxy groups and R.sub.2 is alkyl, phenyl or benzyl groups. The photoreceptor can suppress the photo-deterioration due to cyclic operation and is useful in the field of copying printers.