Fuji Electric Co., Ltd.

Fuji Electric., Ltd.

Shinichi Tamura

Youichi Tei

Tadashi Mimura

Teruaki Kobayashi

Seishi Terasaki

Kenichi Ohkura

Naoki Itoh

Kazumi Egota

Hiroshi Kimura

Yoji Yamada

Tadashi Asakawa

The present invention relates to photoconductors which exhibit excellent electrical properties which are not appreciably affected by environmental changes or by repeated use. Having excellent durability during repeated printing, these photoconductors can be used to obtain large quantities of high-quality output images. The photoconductor according to the invention includes a conductive substrate and a photoconductive film on the conductive substrate. The photoconductive film includes a plurality of charge generation and transport layers, wherein each layer contains a phthalocyanine compound described in the specification by chemical formula (I) as a charge generation agent and a charge transport agent dispersed or dissolved into a binder. The concentration of the charge generation agent in an upper layer is higher than in a lower layer.

Photoconductor for electrophotography

A titanyloxyphthalocyanine crystal to be used as a charge generation material for an electrophotographic photoreceptor, having a maximum diffraction intensity observed at Bragg angle (2 .theta.) of 9.6.degree..+-.0.2.degree. and clear peaks of diffraction intensity observed at 7.22.degree..+-.0.2.degree., 9.60.degree..+-.0.2.degree., 11.60.degree..+-.0.2.degree., 13.40.degree..+-.0.2.degree., 14.88.degree..+-.0.2.degree.,18.34.degree..+-.0.2.degree., 23.62.degree..+-.0.2.degree., 24.14.degree..+-.0.2.degree., and 27.32.degree..+-.0.2.degree., respectively, in an X-ray diffraction spectrum obtained by performing an x-ray diffraction method using CuK.alpha. as a source of radiation. A method for preparing the crystal includes dispersing a predetermined amount of amorphous titanyloxyphthalocyanine in an aqueous solution in which ionic substances are dissolved, under mechanical force at a temperature of under 50.degree. C., to obtain a mixture composed of a fine dispersion of titanyloxyphthalocyanine; adding a non-aqueous organic solvent to the mixture to shift the fine dispersion of titanyloxyphthalocyanine from an aqueous phase to a non-aqueous organic solvent phase; and removing the non-aqueous organic solvent phase to obtain a pellet of titanyloxyphthalocyanine crystal.

Titanyloxyphthalocyanine crystals, and method of preparing the same

Phthalonitrile, an alkali metal or an alkali metal compound, and a hydrogen donor compound are heated in an organic solvent to synthesize a partially hydrogenated alkali metal phthalocyanine, which is then brought into contact with a dealkalizing agent to effect substitution with hydrogen of the partially hydrogenated alkali metal phthalocyanine to thereby obtain high-purity metal-free phthalocyanine. FX-type metal-free phthalocyanine as obtained according to the foregoing procedure may be used as a charge-generating substance to produce an electrophotographic photoconductor of high image quality which is highly sensitive to near infrared rays.

Process for preparing a metal-free phthalocyanine

An electrophotographic photoreceptor includes a conductive substrate and a photosensitive layer including a charge generation material and a charge transport material. The charge generation material is a titanyloxyphthalocyanine crystal having a maximum diffraction intensity observed at Bragg angle (2.theta.) of 9.6.degree..+-.0.2.degree. and clear peaks of diffraction intensity observed at 7.22.degree..+-.0.2.degree., 9.60.degree..+-.0.2.degree., 11.60.degree..+-.0.2.degree., 13.40.degree..+-.0.2.degree., 14.88.degree..+-.0.2.degree., 18.34.degree..+-.0.2.degree., 23.62.degree..+-.0.2.degree., 24.14.degree..+-.0.2.degree., and 27.32.degree..+-.0.2.degree., respectively, in a X-ray diffraction spectrum obtained by performing a X-ray diffraction method using CuK.alpha. as a source of radiation, and having a lattice constant of:

Electrophotographic photoreceptors including titanyloxyphthalocyanine

An electrophotographic photoconductor, includes metal-free phthalocyanine as a charge-generating substance, wherein the X-ray diffraction spectrum of said metal-free phthalocyanine as measured using CuK.alpha. as a radiation source includes intense diffraction peaks at Bragg angles (2.theta..+-.0.2.degree.) of 7.5.degree., 9.0.degree., 16.6.degree., 17.2.degree., 21.5.degree., 22.2.degree., 23.8.degree., and 28.5.degree., and wherein the infrared absorption spectrum of said metal-free phthalocyanine includes four absorption bands with the maximum absorption intensity at a wavenumber of 716 cm.sup.-1 between a wavenumber of 700 cm.sup.-1 and a wavenumber of 760 cm.sup.-1 and a characteristic absorption band at a wavenumber of 3,291.+-.2 cm.sup.-1.

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Kawasaki, Japan

Shinichi Tamura