Abstract: A phthalocyanine crystal of mixed pigments of oxytitanium phthalocyanine and a halogenated gallium phthalocyanine or a halogenated indium phthalocyanine is disclosed. The phthalocyanine crystal of mixed pigments is used as a charge generating material which provides an electrophotographic photoreceptor excellent in sensitivity, stability on repeated use, and environmental stability.

Abstract: A process for preparing an oxytitanium phthalocyanine hydrate crystal which, when dried at 100.degree. C. and 0.1 mmHg for 8 hours and then allowed to stand in air at room temperature for 12 hours, has a structural formula of TiOPc.multidot.(H.sub.2 O).sub.n, wherein Pc represents a phthalocyanine nucleus, and n represents a number of from 0.15 to 1, and elemental analysis values of C: 65.0 to 66.3%, H: 2.5 to 3.1%, and N: 18.5 to 19.3% is disclosed, which process comprises the steps of: mechanically grinding a mixture of oxytitanium phthalocyanine and an inorganic salt to convert the crystal form of the oxytitanium phthalocyanine to a crystal form showing a distinct peak in its X-ray diffraction pattern at a Bragg angle (2.theta..+-.0.2.degree. ) of 27.3.degree. and treating the resulting oxytitanium phthalocyanine crystal with a mixed solvent of water and a water-insoluble organic solvent.

Abstract: Dichlorotin phthalocyanine crystals having distinct diffraction peaks at (i) 8.7.degree., 9.9.degree., 10.9.degree., 13.1.degree., 15.2.degree., 16.3.degree., 17.4.degree., 21.9.degree. and 25.5.degree., or (ii) 9.2.degree., 12.2.degree., 13.4.degree., 14.6.degree., 17.0.degree. and 25.3.degree. of the Bragg angle (2.theta..+-.0.2) to a CuK.alpha. characteristic X-ray; a method of preparing dichlorotin phthalocyanine crystals having the strongest diffraction peak at 28.2.degree. in the range of from 25.degree. to 30.degree. of the Bragg angle (2.theta..+-.0.2) in an X-ray diffraction spectrum; and an electrophotographic photoreceptor comprising an electroconductive support having thereon a light-sensitive layer containing the dichlorotin phthalocyanine crystals having distinct diffraction peaks at the particular angles or the dichlorotin phthalocyanine crystals prepared by the method.

Abstract: An electrophotographic photosensitive member has a charge-generating layer which includes selected photosensitive pigment particles and a compound which is a tetracyanoanthraquinodimethane compound, an anthraquinone compound, a dicyanovinyl compound, or a special quinone compound. The compound is incorporated in an amount in a range from 0.01 to 2 molar equivalents, preferably 0.1 to 1 molar equivalent, to the pigment, which has a positive hole transporting property. The photossensitive member has a charge-transporting layer and can also have a protective layer. The pigment is a phthalocyanine series pigment, a squearyrium series p igment, or a perylene series pigment. A process of using the photosensitive member includes reversal development and multicolor toner transfer. It is found that the process is adaptable to change in size of the transfer medium.

Abstract: An electrophotographic photoreceptor comprising a conductive support having thereon a photosensitive layer is disclosed, wherein a charge transport layer constituting said photosensitive layer or a protective layer formed on said photosensitive layer contains a charge transporting agent, said charge transporting agent being dissolved in a solid state or dispersed in a polycarbonate resin containing a monomer unit represented by formula (I): ##STR1## wherein R.sub.1 represents a hydrogen atom, a methyl group, a cyano group, or a phenyl group; R.sub.2 represents a methyl group, a cyano group, or a phenyl group; or R.sub.1 and R.sub.2 are connected to each other to form a 5- or 6-membered saturated ring; X represents a chlorine atom or a bromine atom; n represents an integer; and m represents 0 or an integer.The photoreceptor exhibits high sensitivity with low residual potential.

Abstract: An electrophotographic photosensitive member has a charge-generating layer which includes selected photosensitive pigment particles and a compound which is a tetracyanoanthraquinodimethane compound, an anthraquinone compound, a dicyanovinyl compound, or a special quinone compound. The compound is incorporated in an amount in a range from 0.01 to 2 molar equivalents, preferably 0.1 to 1 molar equivalent, to the pigment, which has a positive hole transporting property. The photosensitive member has a charge-transporting layer and can also have a protective layer. The pigment is a phthalocyanine series pigment, a squearyrium series pigment, or a perylene series pigment. A process of using the photosensitive member includes reversal development and multicolor toner transfer. It is found that the process is adaptable to change in size of the transfer medium.

Abstract: An electrophotographic photosensitive member has a charge-generating layer which includes selected photosensitive pigment particles and a compound which is a tetracyanoanthraquinodimethane compound, an anthraquinone compound, a dicyanovinyl compound, or a special quinone compound. The compound is incorporated in an amount in a range from 0.01 to 2 molar equivalents, preferably 0.1 to 1 molar equivalent, to the pigment, which has a positive hole transporting property. The photosensitive member has a charge-transporting layer and can also have a protective layer. The pigment is a phthalocyanine series pigment, a squearyrium series pigment, or a perylene series pigment. A process of using the photosensitive member includes reversal development and multicolor toner transfer. It is found that the process is adaptable to change in size of the transfer medium.

Abstract: An electrophotographic photosensitive member has a charge-generating layer which includes selected photosensitive pigment particles and a compound which is a tetracyanoanthraquinodimethane compound, an anthraquinone compound, a dicyanovinyl compound, or a special quinone compound. The compound is incorporated in an amount in a range from 0.01 to 2 molar equivalents, preferably 0.1 to 1 molar equivalent, to the pigment, which has a positive hole transporting property. The photosensitive member has a charge-supporting layer and can also have a protective layer. The pigment is a phthalocyanine series pigment, a squearyrium series pigment, or a perylene series pigment. A process of using the photosensitive member includes reversal development and multicolor toner transfer. It is found that the process is adaptable to change in size of the transfer medium.

Abstract: A fluorene derivative useful as an electron transport material is disclosed, which is represented by formula (I) ##STR1## wherein R.sub.1 represents a hydrogen atom or a phenyl group, R.sub.2 represents a hydrogen atom, a nitro group, or an alkoxycarbonyl group, and R.sub.3 and R.sub.4 each represents a hydrogen atom or an alkyl group.

Abstract: An electrophotographic photoreceptor is disclosed, comprising a conductive substrate having thereon a photosensitive layer, wherein the photosensitive layer comprises at least one compound selected from the group consisting of a compound of formula (I), a compound of formula (II), and a compound of formula (III) as defined below: ##STR1## wherein X.sup.I represents a cyano group, an alkoxycarbonyl group, or an aryloxycarbonyl group; R.sup.I.sub.1 and R.sup.I.sub.2 each represents a hydrogen atom, an alkyl group, an aryl group, an alkoxycarbonyl group, an aryloxycarbonyl group, an alkylcarbonyl group, an arylcarbonyl group, a nitro group, a halogen atom, or a cyano group; A.sup.I represents ##STR2## wherein R.sup.I.sub.3 and R.sup.I.sub.9 each represents a hydrogen atom, an alkyl group, a nitro group, a halogen atom, or a cyano group; and m and n each represents an integer of 0 to 3; ##STR3## wherein X.sup.II represents O, C(CN).sub.2 or C(CO.sub.2 R.sup.II).sub.2, wherein R.sup.II is an alkyl group; R.sup.II.

Abstract: An electrophotographic photoreceptor is disclosed, comprising an electrically conductive substrate having thereon and a light-sensitive layer, said light-sensitive layer comprising an electric charge generating layer and an electric charge transporting layer, wherein the electric charge generating layer contains an electric charge generating organic pigment having positive hole transporting properties and a pyrylium compound represented by the formula (I) or (II): ##STR1## wherein X is an oxygen atom or a sulfur atom; R.sub.1 to R.sub.5 are each a hydrogen atom, and alkyl group, a cycloalkyl group, an alkoxycarbonyl group, a benzyl group, a substituted or unsubstituted styryl group, or a substituted or unsubstituted phenyl group, and Z.sup..crclbar. is an anion.

Abstract: A novel tetracyanoanthraquinodimethane derivative and a process for producing it are disclosed, the tetracyanoanthraquinodimethane derivative being represented by formula: ##STR1## wherein R, m, and n are as defined in the specification. A solid charge transfer complex of the tetracyanoanthraquinodimethane derivative with an electron donating compound and a process for producing it are also disclosed.

Abstract: An electrophotographic photoreceptor comprising a conductive substrate and a photosensitive layer on the conductive substrate, wherein the photosensitive layer contains a compound of formula (I) as a charge transporting agent: ##STR1## wherein R.sub.1 and R.sub.2 each represents a hydrogen atom, an alkyl group, an aryl group, an alkoxycarbonyl group, an aryloxycarbonyl group, a nitro group, a halogen atom, an alkylcarbonyl group or an arylcarbonyl group; Y represents ##STR2## X.sub.1 and X.sub.2 may be the same or different groups and are selected from a cyano group or an alkoxycarbonyl group; Z represents ##STR3## R.sub.3 represents a substituted or unsubstituted aryl or nitrogen-containing heterocyclic group; R.sub.4, R.sub.5 and R.sub.6 each represents a hydrogen atom, an alkyl group, an aralkyl group, an aryl group or a heterocyclic group; when Z is the ##STR4## group, R.sub.1 and R.sub.2 are not the alkylcarbonyl group; m is 0 or 1; n is 0 to 2; and when n is 2, the R.sub.

Abstract: Fluorene derivatives represented by the general formula (I): ##STR1## wherein R represents an alkyl group having 1 to 8 carbon atoms, a phenyl group of a C.sub.1 -C.sub.8 alkyl-substituted phenyl group, and a process for preparation thereof. These fluorene derivatives are synthesized by reacting fluorenone derivatives represented by the general formula (II): ##STR2## wherein R is the same as defined above, with malonitrile.

Abstract: Benzophenone derivatives which are useful in electrophotographic light-sensitive material represented by formula (I): ##STR1## wherein A represents the structural formula (a), (b) or (c): ##STR2## and R represents an alkyl group having 1 to 8 carbon atoms or a nitro group, and a process for preparation thereof. These benzophenone derivatives can be synthesized by reacting compounds represented by formula (II): ##STR3## wherein A and R are the same as defined above, with malonitrile.

Abstract: An electrophotographic photosensitive member has a charge-generating layer which includes selected photosensitive pigment particles and a compound which is a tetracyanoanthraquinodimethane compound, an anthraquinone compound, a dicyanovinyl compound, or a special quinone compound. The compound is incorporated in an amount in a range from 0.01 to 2 molar equivalents, preferably 0.1 to 1 molar equivalent, to the pigment, which has a positive hole transporting property. The photosensitive member has a charge-transporting layer and can also have a protective layer. The pigment is a phthalocyanine series pigment, a squarylium series pigment, or a perylene series pigment. A process of using the photosensitive member includes reversal development and multicolor toner transfer. It is found that the process is adaptable to change in size of the transfer medium.

Abstract: A novel tetracyanoanthraquinodimethane derivative and a process for producing it are disclosed, the tetracyanoanthraquinodimethane derivative being represented by formula: ##STR1## wherein R, m, and n are as defined in the specification. A solid charge transfer complex of the tetracyanoanthraquinodimethane derivative with an electron donating compound and a process for producing it are also disclosed.

Abstract: An electrophotographic photoreceptor is disclosed, which comprises an electrically conductive support having provided thereon a photoconductive layer containing, as a charge transport material, a compound represented by formula (I) ##STR1## wherein R.sub.1 represents an alkyl group, and R.sub.2 and R.sub.3, which may be the same or different, each represents a hydrogen atom, an alkyl group, an alkoxy group, a halogen atom, an alkoxycarbonyl group, or a substituted amino group. The photoreceptor satisfies both electrical and mechanical requirements without undergoing adverse influences from binder resins used therein.

Abstract: An electron-accepting compound represented by the formula (I): ##STR1## wherein R represents a hydrogen atom or --B(Mes).sub.2 and Mes represents a mesityl group.A method for preparing an electron-accepting compound represented by the above-described formula (I), which comprises condensing a benzophenone derivative represented by the following formula (II) with malononitride, ##STR2## wherein R and Mes have the same meanings as defined for the formula (I).