Abstract: Hydrazone compounds having the general formula ##STR1## wherein Ar is selected from the group consisting of a naphthalene ring radical, substituted naphthalene ring radicals, an anthracene ring radical, substituted anthracene ring radicals, styryl, substituted styryls, a pyridine radical, a furan ring radical and a thiophene ring radical.The hydrazone compounds can be prepared by allowing 1-methyl-1-phenylhydrazine having the formula ##STR2## to react with an aldehyde represented by the general formula Ar-CHO, wherein Ar is the same as mentioned above at a substantially equal molar ratio in an organic solvent selected from the group consisting of lower alcohols, cyclic ethers, cellosolves, N,N-dimethylforamide and acetic acid, in the presence of an acid catalyst, by heating and refluxing the reaction mixture.

Abstract: Bis-azo compounds represented by the general formula ##STR1## where A represents ##STR2## wherein R represents alkyl, alkoxy, nitro, dialkylamino or halogen, and n represents an integer 0, 1, 2 or 3 and when n is 2 or 3, R represents identical or different substituents selected from the group of alkyl, alkoxy, nitro, dialkylamino and halogen.

Abstract: The present invention provides electrophotographic sensitive materials having a high sensitivity as well as a high flexibility which comprise a conductive support and a photosensitive layer formed thereon, said photosensitive layer containing one disazo pigment, as an effective ingredient, which is selected from the group consisting of disazo pigments expressed by the following general formulas I, II, III, and IV, ##STR1## [(wherein A is selected from the group consisting of ##STR2## is selected from the group consisting of aromatic rings such as benzene ring, naphthalene ring, etc., hetero rings such as indole ring, carbazole ring, benzofuran ring, etc. and their substituents, Ar.sub.1 is selected from the group consisting of aromatic rings such as benzene ring, naphthalene ring, etc., hetero rings such as dibenzofuran, etc. and their substituents, Ar.sub.2 and Ar.sub.3 are selected from the group consisting of aromatic rings such as benzene ring, naphthalene ring, etc. and their substituents, R.sub.1 and R.

Abstract: An electrophotographic element utilizing as a charge generation material a disazo pigment having the following general formula: ##STR1## where R.sup.1 is hydrogen, chlorine, bromine, methyl, ethyl, methoxy, ethoxy, nitro, dimethylamino, diethylamino or phenyl; m and n are each an integer such as 1 or 2; and R.sup.2 is hydrogen or chlorine.

Abstract: The present invention provides electrophotographic sensitive materials having a high sensitivity as well as a high flexibility which comprise a conductive support and a photosensitive layer formed thereon, said photosensitive layer containing one disazo pigment, as an effective ingredient, which is selected from the group consisting of disazo pigments expressed by the following general formulas I, II, III, and IV, ##STR1##

Abstract: The present invention provides disazo compounds expressed by the general formula: ##STR1## [wherein A represents a member selected from the group consisting of ##STR2## (wherein X represents a member selected from the group consisting of aromatic rings such as benzene ring, naphthalene ring, etc., hetero rings such as indole ring, carbazole ring, benzofuran ring, etc. and their substituents, Ar.sub.1 represents a member selected from the group consisting of aromatic rings such as benzene ring, naphthalene ring, etc., hetero rings such as dibenzofuran ring, etc. and their substituents, Ar.sub.2 and Ar.sub.3 represent a member selected from the group consisting of aromatic rings such as benzene ring, naphthalene ring, etc. and their substituents, R.sub.1 and R.sub.3 represent a member selected from the group consisting of hydrogen, lower alkyl radical or phenyl radical and their substituents and R.sub.

Abstract: The present invention provides an electrophotographic element of a high sensitivity and a high flexibility comprising an electroconductive support and a photosensitive layer provided thereon and containing as an effective ingredient therein a disazo compound represented by the following general formula: ##STR1## wherein A is a radical selected from the group consisting of: ##STR2## in which X represents a ring selected from the group consisting of aromatic rings such as benzene ring and naphthalene ring, hetero rings such as indole ring, carbazole ring and benzofuran ring, and substituted derivatives thereof; Ar.sub.1 represents a radical selected from the group consisting of aromatic rings such as benzene ring and naphthalene ring, hetero rings such as dibenzofuran ring and substituted derivatives thereof; Ar.sub.2 and Ar.sub.3 represent radicals respectively selected from the group consisting of aromatic rings such as benzene ring and naphthalene ring, and substituted derivatives thereof; R.sub.1 and R.sub.

Abstract: The present invention provides disazo compounds expressed by the general formula I ##STR1## a process for the preparation of said compounds; and electrophotographic sensitive material having a high sensitivity as well as a high flexibility which comprise a conductive support and a photosensitive layer formed thereon, said photosensitive layer containing a disazo compound, as an effective ingredient, which is expressed by the general formula II A'--N.dbd.N--Z--N.dbd.N--A'.

Abstract: The present invention provides disazo compounds expressed by the general formula: ##STR1## [wherein A represents a member selected from the group consisting of ##STR2## (wherein X represents a member selected from the group consisting of aromatic rings such as benzene ring, naphthalene ring, etc., hetero rings such as indole ring, carbazole ring, benzofuran ring, etc. and their substituents, Ar.sub.1 represents a member selected from the group consisting of aromatic rings such as benzene ring, naphthalene ring, etc., hetero rings such as dibenzofuran ring, etc. and their substituents, Ar.sub.2 and Ar.sub.3 represent a member selected from the group consisting of aromatic rings such as benzene ring, naphthalene ring, etc. and their substituents, R.sub.1 and R.sub.3 represent a member selected from the group consisting of hydrogen, lower alkyl radical or phenyl radical and their substituents and R.sub.

Abstract: An electrophotographic element according to the present invention exhibits an exceedingly high sensitivity and it comprises (1) an electroconductive support, a charge producing layer consisting essentially of a charge producing substance and a charge transport layer consisting essentially of a charge transport substance having the following general formula and a binder, the last-mentioned two layers being superposed in that order or vice versa on said support, or (2) an electroconductive support and a photosensitive layer, superposed thereon, and consisting essentially of a charge producing substance, a charge transport substance having said general formula and a binder: ##STR1## (wherein n is an integer of 1 or 2, R.sub.1 stands for hydrogen atom or an alkyl, nitro, dialkylamino, alkoxy, nitrile or carboxylic ester group, and R.sub.2 and R.sub.3 stand for hydrogen or halogen atom or nitro or dialkylamino group respectively).