Sharp Kabushiki Kaisha Corporation

Takahiro Teramoto

Satoshi Katayama

Kiyofumi Morimoto

Kazuya Ishida

Kazushige Morita

Akihiko Kawahara

Tomoko Kanazawa

Takatsugu Obata

Tatsuhiro Morita

Satoshi Machino

Masato Miyauchi

Akihiro Kondo

Yuko Takeda

Kaori Fujii

An object of the invention is to improve the photosensitivity characteristics, characteristics on repeated use and stability of a photoreceptor. A photosensitive layer formed on a conductive support of a photoreceptor contains crystalline oxotitanylphthalocyanine having major peaks in an X-ray diffraction spectrum at Bragg angles (2&thgr;&plusmn;0.2&deg;) of 7.3&deg;, 9.4&deg;, 9.6&deg;, 11.6&deg;, 13.3&deg;, 17,9&deg;, 24.1&deg; and 27.2&deg;, wherein a peak bundle formed by overlapping the peaks at 9.4&deg; and 9.6&deg; is the largest peak, and the peak at 27.2&deg; is the secondary largest peak as a charge generating substance. Furthermore, it contains a bisamine compound, an N,N&prime;-bisenamine compound, a styryl compound, an amine-hydrazone compound, a benzofuran-bishydrazone compound, a bisenamine compound, a benzofuran-bishydrazone compound or a benzofuran-bis-cyclic hydrazone compound represented by the particular structural formulae as a charge transporting substance.

Crystalline oxotitanylphthalocyanine and electrophotographic photoreceptor using the same

The object of the invention is to provide a highly characteristic and lesser defective image using an electrophotographic photoreceptor which can be produced with a better coating property and which is highly sensitive and hardly loses the electrostatic stability during repeated use. A water-soluble or water/alcohol-soluble polyvinyl acetal and an inorganic pigment are involved in an underlayer provided between a conductive support and a photoconductive layer. Particularly, it is favorable to use titanium oxide as the inorganic pigment, make the ratio of polyvinyl acetal/titanium oxide 1/9-9/1 by weight, make the underlayer 0.5-5 .mu.m in thickness, use the titanium oxide of which the surface is treated with alumina, use the titanium oxide of which the titanium oxide component is 95% by weight or lower and of which the surface is treated with alumina, use the polyvinyl acetal of which the sodium ion concentration is 40 ppm or lower, and use the photo-conductive layer which contains a vinyl chloride-vinyl acetate type copolymer. As for a dispersing medium for coating the underlayer, water/alcohol=1/9-7/3 (ratio by weight) is selected. The aforementioned photoreceptor is applied to an image-forming apparatus using an inversion development process.

Electrophotographic photoreceptor, process for production thereof, and

An object of the invention is to provide a highly characteristic image using an electrophotographic photoreceptor of which a charge-generating layer can be produced with a better coating property and which is highly sensitive and electrostatically highly stable in repeated use. The charge-generating layer of a function-separated type photoreceptor contains a n-type non-metallic phthalocyanine and a copolymer of vinyl chloride-vinyl acetate type. Particularly, the ratio of the .tau.-type non-metallic phthalocyanine to the copolymer of vinyl chloride-vinyl acetate type is fixed at 1/3-3/1 by weight. The thickness of the charge-generating layer is fixed at 0.1-0.6 .mu.m. As the copolymer of vinyl chloride-vinyl acetate type, copolymers of vinyl chloride-vinyl acetate, vinyl chloride-vinyl acetate-maleic acid, or vinyl chloride-vinyl acetate-vinyl alcohol are selected. Particularly, it is favorable to select those containing at least 10% by weight of the vinyl alcohol component. The charge-generating layer is formed with a liquid coating material using a ketone solvent as dispersant. The aforementioned photoreceptor is applied to an image-forming apparatus using an inversion development process.

Electrophotographic photoreceptor, process for producing the same, and

An object of the invention is to provide an electrophotographic photoconductor featuring uniform chargeability to a predetermined potential, low residual potential and excellent stability in the operating environment and repeated use thereof, as well as a method of producing the same. An undercoat layer between a substrate and a photosensitive layer is formed by the use of a coating fluid for undercoat layer containing a coupling agent having an unsaturated bond, a metal oxide, a binder and a mixture solvent. The coupling agent increases affinity of the metal oxide for the binder so that the coating fluid does not suffer the aggregation of the metal oxide or gelation thereof, presenting homogeneity and excellent can-stability. Thus is obtained a uniform undercoat layer. A photoconductor having this undercoat layer is adapted to be uniformly charged to a predetermined potential and to suppress the rise of residual potential and particularly the rise of residual potential due to a use thereof under low-temperature, low-humidity conditions or the repeated use thereof over an extended period of time, thus offering a high photosensitivity in a stable manner.

Electrophotographic photoconductor and method of producing same

Growing community of inventors

Tenri, Japan

Takahiro Teramoto