Abstract: A process for preparing chlorogallium phthalocyanine comprising the steps of: reacting gallium trichloride and phthalonitrile or diiminoisoindoline in an aromatic hydrocarbon solvent; and treating the resulting chlorogallium phthalocyanine with a second solvent different from the aromatic hydrocarbon solvent.

Abstract: A novel dichlorotin phthalocyanine crystal having distinct diffraction peaks at 8.5.degree., 11.2.degree., 14.5.degree., and 27.2.degree. of the Bragg angles (2.theta..+-.0.2) in the X-ray diffraction spectrum; a process for producing the dichlorotin phthalocyanine crystal, comprising mechanically grinding a known dichlorotin phthalocyanine crystal together with an inorganic salt, followed by, if desired, a solvent treatment; an electrophotographic photoreceptor containing, in the photosensitive layer thereof, the dichlorotin phthalocyanine crystal; and a coating composition for producing an electrophotographic photoreceptor, comprising the dichlorotin phthalocyanine crystal, a binder resin, and an acetic ester solvent. The photoreceptor exhibits high sensitivity and excellent durability. The coating composition maintains the dichlorotin phthalocyanine crystal in its desired form either while being prepared or after being coated.

Abstract: A process for preparing a purified hydroxymetal phthalocyanine with stable charging characteristics and small dark decay and an electrophotographic photoreceptor containing the same are disclosed. The process comprises dissolving or slurrying a precursor of a hydroxymetal phthalocyanine in an acid, precipitating a hydroxymetal phthalocyanine in a solvent or a basic solution, and heat treating the resulting hydroxymetal phthalocyanine in a basic solution. The purified hydroxymetal phthalocyanine wherein the metal is gallium is further subjected to a solvent treatment to provide a new crystal showing further improved electrophotographic characteristics.

Abstract: A process for preparing hydroxygallium phthalocyanine crystals showing intense diffraction peaks at Bragg angles (2.theta..+-.0.2) of 7.5.degree., 25.1.degree., and 28.3.degree. with respect to CuK.sub..alpha. characteristic X-rays which comprises mechanically grinding hydroxygallium phthalocyanine and then treating the grains with a solvent is disclosed. The hydroxygallium phthalocyanine crystals obtained by the process of the present invention has a novel crystal form and exhibits high sensitivity and excellent durability on repeated use as well as crystal form stability. The electrophotographic photoreceptor prepared by using the resulting hydroxygallium phthalocyanine exhibits excellent electrophotographic characteristics.

Abstract: An electrophotographic photoreceptor high in sensitivity and contrast potential after light irradiation is disclosed. The photoreceptor comprises an electroconductive substrate having thereon a photoconductive layer comprising a charge generating layer comprising a charge generating material, and a charge transporting layer comprising a charge transporting material, wherein the ionization potential IPg of the charge generating material is lower than the ionization potential IPt of the charge transporting material, the difference therebetween is 0.35 eV or less, and the difference between the ionization potential IPg1 of the charge generating layer and the ionization potential IPt1 of the charge transporting layer is within the range of -0.1 to +0.1 eV.

Abstract: A dichlorotin phthalocyanine crystal showing, in the X-ray diffractometry using a CuK.sub..alpha. ray, a peak at a Bragg angle (2.theta..+-.0.2.degree.) of 28.2.degree. with any other peak(s) observed at a Bragg angle(s) between 25.degree. and 30.degree. having an intensity of not more than 30% of that of the peak at 28.2.degree.. The crystal is useful as a photoconductive material having sensitivity in the longer wavelength region. The electrophotographic photoreceptor containing the crystal exhibits high sensitivity and excellent durability.

Abstract: An electrophotographic photoreceptor is disclosed, which comprises an electrically conductive substrate having formed thereon at least a charge generating layer and a charge transporting layer, wherein said charge generating layer is formed using a dispersed coating liquid prepared by mechanically grinding a perylene pigment and dispersing the ground perylene pigment in water, an alcohol series solvent, or an acetic acid ester solvent. A process of producing the photoreceptor is also disclosed. The electrophotographic photoreceptor provides a long pot life and stabilized dispersibility and electric characteristics.

Abstract: A halogenated hydroxygallium phthalocyanine crystal shows intense diffraction peaks at Bragg angles (2.THETA..+-.0.2.degree.) of (1) 7.7.degree., 16.5.degree., 25.1.degree. and 26.6.degree.; (2) 7.9.degree., 16.5.degree., 24.4.degree., and 27.6.degree.; (3) 7.0.degree., 7.5.degree., 10.5.degree., 11.7.degree., 12.7.degree., 17.3.degree., 18.1.degree., 24.5.degree., 26.2.degree., and 27.1.degree.; (4) 7.5.degree., 9.9.degree., 12.5.degree., 16,3.degree., 18.6.degree., 25.1.degree., and 28.3.degree. or (5) 6.8.degree., 12.8.degree., 15.8.degree., and 26.0.degree. and is suited for use in an electrophotographic photoreceptor is disclosed.

Abstract: Crystals of hydroxygallium phthalocyanine, a method of preparing the crystals, a photoconductive material containing the crystals, and an electrophotographic photoreceptor having the material. The photoreceptor has excellent electrophotographic characteristics. The crystals of hydroxygallium phthalocyanine have distinct diffraction peaks at (i) 7.5.degree., 9.9.degree., 12.5.degree., 16.3.degree., 18.6.degree., 25.1.degree. and 28.3.degree., or (ii) 7.7.degree., 16.5.degree., 25.1.degree. and 26.6.degree., or (iii) 7.9.degree., 16.5.degree., 24.4.degree. and 27.6.degree., or (iv) 7.0.degree., 7.5.degree., 10.5.degree., 11.7.degree., 12.7.degree., 17.3.degree., 18.1.degree., 24.5.degree., 26.2.degree. and 27.1.degree., or (v) 6.8.degree., 12.8.degree., 15.8.degree. and 26.0.degree. or (vi) 7.4.degree., 9.9.degree., 25.0.degree., 26.0.degree., and 28.2.degree. of the Bragg angle (2.theta..+-.0.2) in the X-ray diffraction spectrum.

Abstract: Oxytitanium phthalocyanine hydrate crystal and an electrophotographic photoreceptor using said crystal are disclosed. The structural formula of the crystal is TiOPc(H.sub.2 O).sub.n wherein Pc represents a phthalocyanine residual group, and n represents from 0.15 to 1; and the elemental analysis values of C, H and N are as follows: C: 65.0 to 66.3 %; H: 2.5 to 3.1 %; and N: 18.5 to 19.3 %.

Abstract: A phthalocyanine mixed crystal comprising a halogenated indium phthalocyanine and a halogenated gallium phthalocyanine and an electrophotographic photoreceptor containing the phthalocyanine mixed crystal. The phthalocyanine mixed crystal is a charge generating material which provides an electrophotographic photoreceptor excellent in sensitivity, stability on repeated use, and environmental stability.

Abstract: A process for preparing a hydroxymetal phthalocyanine pigment containing a central metal atom selected from aluminum, gallium, indium, silicon, germanium and tin and having a novel crystal form is disclosed, comprising treating a precursor of a hydroxymetal phthalocyanine pigment with an acid and treating the precipitated hydroxymetal phthalocyanine pigment with a solvent under an acidic condition. The resulting hydroxymetal phthalocyanine pigment includes hydroxygallium crystals showing distinct diffraction peaks at Bragg angles (2.theta..+-.0.2.degree.) of (1) 8.2.degree., 12.4.degree., 16.5.degree. and 26.3.degree. or (2) 6.8.degree., 12.5.degree. and 26.4.degree.. The resulting hydroxymetal phthalocyanine pigment exhibits high photosensitivity and excellent stability as a charge generating material of an electrophotographic photoreceptor.

Abstract: Crystals of chlorogallium phthalocyanine, having distinct diffraction peaks at (i) 7.4.degree., 16.6.degree., 25.5.degree. and 28.3.degree., (ii) 6.8.degree., 17.3.degree., 23.6.degree. and 26.9.degree., or (iii) 8.7.degree. to 9.2.degree., 17.6.degree., 24.0.degree., 27.4.degree. and 28.8.degree. of the Bragg angle (2.theta..+-.0.2) to a CuK.alpha. characteristic X-ray; a photoconductive material for electrophotographic photoreceptor comprising the chlorogallium phthalocyanine; and an electrophotographic photoreceptor comprising an electroconductive support having thereon a light-sensitive layer containing at least one or more of chlorogallium phthalocyanine crystals. The electrophotographic photoreceptor has excellent sensitivity and durability.

Abstract: A novel dichlorotin phthalocyanine crystal having distinct diffraction peaks at 8.5.degree., 11.2.degree., 14.5.degree., and 27.2.degree. of the Bragg angles (2.theta..+-.0.2) in the X-ray diffraction spectrum; process for producing the dichlorotin phthalocyanine crystal, comprising mechanically grinding a known dichlorotin phthalocyanine crystal together with an inorganic salt, followed by, if desired, a solvent treatment; an electrophotographic photoreceptor containing, in the photosensitive layer thereof, the dichlorotin phthalocyanine crystal; and a coating composition for producing an electrophotographic photoreceptor, comprising the dichlorotin phthalocyanine crystal, a binder resin, and an acetic ester solvent. The photoreceptor exhibits high sensitivity and excellent durability. The coating composition maintains the dichlorotin phthalocyanine crystal in its desired form either while being prepared or after being coated.

Abstract: A novel phthalocyanine mixed crystal comprising a dihalogenotin phthalocyanine and a halogenogallium phthalocyanine and an electrophotographic photoreceptor containing the same are disclosed. The phthalocyanine mixed crystal preferably has an intense X-ray diffraction peak at a Bragg angle (2.theta..+-.0.2.degree.) of 26.9. The phthalocyanine mixed crystal is useful as a charge generating material which provides an electrophotographic photoreceptor excellent in sensitivity, stability on repeated use, and environmental stability.

Abstract: A dichlorotin phthalocyanine crystal showing, in the X-ray diffractometry using a CuK.sub..alpha. ray, a peak at a Bragg angle (2.theta..+-.0.2.degree.) of 28.2.degree. with any other peak(s) observed at a Bragg angle(s) between 25.degree. and 30.degree. having an intensity of not more than 30% of that of the peak at 28.2.degree.. The crystal is useful as a photoconductive material having sensitivity in the longer wavelength region. The electrophotographic photoreceptor containing the crystal exhibits high sensitivity and excellent durability.

Abstract: Disclosed are novel crystals of hydroxyindium phthalocyanine, having distinct diffraction peaks at the particular angles of the Bragg angle (2.theta..+-.0.2) in the X-ray diffraction pattern. An electrophotographic photoreceptor comprising an electroconductive support having thereon a light-sensitive layer containing at least one of an amorphous hydroxyindium phthalocyanine and the above hydroxyindium phthalocyanine crystals. The electrophotographic photoreceptor has excellent sensitivity and durability.

Abstract: Crystals of hydroxygallium phthalocyanine, a method of preparing the crystals, a photoconductive material containing the crystals, and an electrophotographic photoreceptor having the material. The photoreceptor has excellent electrophotographic characteristics. The crystals of hydroxygallium phthalocyanine have distinct diffraction peaks at (i) 7.5.degree., 9.9.degree., 12.5.degree., 16.3.degree., 18.6.degree., 25.1.degree. and 28.3.degree., or (ii) 7.7.degree., 16.5.degree., 25.1.degree. and 26.6.degree., or (iii) 7.9.degree., 16.5.degree., 24.4.degree. and 27.6.degree., or (iv) 7.0.degree., 7.5.degree., 10.5.degree., 11.7.degree., 12.7.degree., 17.3.degree., 8.1.degree., 24.5.degree., 26.2.degree. and 27.1.degree., or (v) 6.8.degree., 12.8.degree., 15.8.degree. and 26.0.degree. or (vi) 7.4.degree., 9.9.degree., 25.0.degree., 26.0.degree., and 28.2.degree. of the Bragg angle (2.theta..+-.0.2) in the X-ray diffraction spectrum.

Abstract: A phthalocyanine mixed crystal comprising a halogenated indium phthalocyanine and a halogenated gallium phthalocyanine and an electrophotographic photoreceptor containing the phthalocyanine mixed crystal. The phthalocyanine mixed crystal is a charge generating material which provides an electrophotographic photoreceptor excellent in sensitivity, stability on repeated use, and environmental stability.

Abstract: Oxytitanium phthalocyanine hydrate crystal and an electrophotographic photoreceptor using said crystal are disclosed. The structural formula of the crystal is TiOPc(H.sub.2 O).sub.n wherein Pc represents a phthalocyanine residual group, and n represents from 0.15 to 1; and the elemental analysis values of C, H and N are as follows: C: 65.0 to 66.3%; H: 2.5 to 3.1%; and N: 18.5 to 19.3%.