Electrophotographic photosensitive material with electron donors and electron acceptors

Claim 1

An electrophotographic element, which comprises: an electrically conductive support; a first layer overlying said support, the electrophotographically active constituents of said first layer consisting essentially of (1) a photoconductive substance capable of generating conductive charge carriers through light absorption and (2) either an electron donor or an electron acceptor, the weight ratio of (1) said photoconductive substance to (2) said electron donor or said electron acceptor being from 1/10 to 1/0.1, said photoconductive substance being selected from the group consisting of Se, Se alloy, CdS, CdSe, ZnO, ZnS, TiO, phthalocyanine pigment, azo pigment, indigo pigment, perylene pigment and polycyclic quinone pigment, said electron donor being selected from the group consisting of poly-N-vinyl carbazole and derivatives thereof, poly-γ-carbazolyl ethyl glutamate and derivatives thereof, pyrene-formaldehyde condensate and derivatives thereof, anthracene-formaldehyde condensate, N-ethyl carbazole-formaldehyde condensate, polyphenylene pyrazole, poly-1-allyl-4,5-diphenyl imidazole, polyvinyl pyrene, polyvinyl phenanthrene, polyacenaphthylene, polyvinyl dibenzothiophene, polyvinyl anthracene, oxazole, oxadiazole, pyrazole, imidazole derivatives, anthracene, tetraphene and pyrene, and said electron acceptor being selected from the group consisting of fluorenone derivatives, dibenzothiophene derivatives, indenothiophene derivatives, phenanthrene quinone derivatives, indenopyridine derivatives, thioxanthone derivatives, benzo cinnoline derivatives, phenazine oxide derivatives, tetracyanoethylene, tetracyanoquinodimethane, bromanil, chloranil, benzoquinone, naphthoquinone, anthraquinone derivatives, phthalic anhydride, picric acid, trichloroacetic acid, tetrabromonaphthoquinone, 1,5-dinitronaphthalene, 2,4,5,7-tetranitrofluorenone, 1,4-dibromonaphthalene, pyrene-3-aldehyde and 9-acetylanthracene; and a second layer overlying and adjacent to said first layer, the electrophotographically active constituent of said second layer consisting essentially of said electron donor or said electron acceptor, with the proviso that when said first layer contains said electron donor said second layer contains said electron acceptor and when said first layer contains said electron acceptor said second layer contains said electron donor, and neither of said first layer and said second layer contains both an electron donor and an electron acceptor.