Sharp Kabushiki Kaisha Corporation

Tomoko Kanazawa

Satoshi Katayama

Kotaro Fukushima

Tatsuhiro Morita

Kazushige Morita

Tadashi Nakamura

Kiyofumi Morimoto

Hiroshi Sugimura

Koichi Toriyama

Masayuki Sakamoto

Akihiko Kawahara

Yoshihide Shimoda

Rikiya Matsuo

Satoshi Machino

Makoto Kurokawa

Takahiro Kurauchi

Takahiro Teramoto

Chikako Iibachi

Masaki Hashimoto

Takatsugu Obata

Mikio Kakui

Akihiro Kondoh

Hisayuki Utsumi

Kazuya Ishida

Akiko Kihara

Shinya Mimura

Sayaka Fujita

Katsuya Takano

Yohichi Takesawa

Hiroko Ishibashi

Kimiko Kumazawa

The present invention provides an electrophotographic photoreceptor comprising a multilayered photosensitive layer or a monolayer photosensitive layer,

Electrophotographic photoreceptor and image forming apparatus provided with the same

An electrophotographic photoreceptor having a photosensitive layer formed on a conductive substrate, wherein the photosensitive layer contains oxygen-containing fluorinated fine particles in a surface layer thereof, and the oxygen-containing fluorinated fine particles have an oxygen composition ratio of 0.9 to 3.0% by atom based on the whole composition of the fine particles according to an X-ray fluorescence composition analysis.

Electrophotographic photoreceptor and image forming apparatus including the same

An electrophotographic photoconductor containing at least a charge generation material and a charge transport material on a conductive support, the electrophotographic photoconductor comprising a diamine compound represented by the formula (1), and also a polyarylate resin having a structural unit represented by the following formula (I). 

Electrophotographic photoconductor and image forming apparatus provided with the same

An electrophotographic photoreceptor of high durability capable of providing stable excellent electrical characteristics over a prolonged period of time, which electrophotographic photoreceptor excels in mechanical strength. A photosensitive layer () of an electrophotographic photoreceptor () includes a polyarylate resin having structural units, for example, those of formula (1) and an enamine compound represented by, for example, formula (2) The variables R, R, R, R, R&#x2dc;R, X, Ar, Ar, Ar, Ar, Ar, R, R, R, R, a, m, and n are as defined in the specification. By virtue of these, the electrophotographic photoreceptor () of excellent mechanical strength and favorable electrical characteristics can be realized.

An electrophotographic photoconductor containing a conductive substrate and at least a charge generating layer and a charge transporting layer successively layered on the substrate, wherein the charge transporting layer contains a charge transporting material (M) and a binder resin (B) and further has a layered structure composed of a plurality of the charge transporting layers wherein the outermost layer of the charge transporting layers show 50% or higher elastic power (&#x3b7;) and hardness (Hplast) of plastic deformation in a range from 220 N/mmor higher to 275 N/mmor lower.

Electrophotographic photoconductor

An electrophotographic photoreceptor having an organic photosensitive layer at the surface layer is provided which can improve the wear resistance, durability and operation stability of the surface layer and can form images with no injury and unevenness in the density for a long period of time. The electrophotographic photoreceptor includes a conductive substrate, an undercoat layer, and a photosensitive layer having a charge generating layer and a charge transporting layer. In the photoreceptor, the photosensitive layer has a creep value Cof 2.70% or more and an elastic ratio &#x3b7;of 47% or more in a case where an indentation maximum load of 5 mN is loaded on the surface under a circumstance at a temperature of 25&#xb0; C. and at a relatively humidity of 50%.

Electrophotographic photoreceptor and image forming apparatus

Test method and control method for coating liquid for electrophotographic photoconductor

Highly sensitive and highly durable electrophotographic photoreceptors which generate faultless images can be produced by forming the under-coating layer on the conductive support and forming the photoreceptive layer on the layer. The under-coating layer contains dendritic titanium oxide. The under-coating layer contains the dendritic titanium oxide of which the surface is coated with (a) metal oxide(s) and/or (an) organic compound(s). The photoreceptive layer contains a phthalocyanine pigment, and the under-coating layer contains dendritic or needle-like titanium oxide of which the surface is coated with (a) metal oxide(s) and/or (an) organic compound(s). The photoreceptive layer contains a phthalocyanine pigment, and the under-coating layer contains dendritic or needle-like titanium oxide, of which the surface is coated with (a) metal oxide(s) and/or (an) organic compound(s), and an alcohol soluble polyamide resin.

Electrophotographic photoreceptor, process for production thereof, and

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.

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

An object of the present invention is to improve the storage stability of a coating liquid for forming a photosensitive layer of a photosensitive member for electrophotography as well as to improve the electrophotography properties of a photosensitive member produced by applying the coating liquid. A photosensitive member for electrophotography is produced by applying a coating liquid composition for a photosensitive member for electrophotography prepared by dissolving or dispersing an organic photoconductive compound and a binder resin in a solvent, and further containing an aliphatic unsaturated hydrocarbon on an electroconductive substrate, and drying for forming a photosensitive layer on the electroconductive substrate.

Coating liquid composition for photosensitive member for

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Kashihara, Japan

Tomoko Kanazawa