Kyocera Mita Corporation

Mita Industrial Co., Ltd.

Kyocera Document Solutions Inc.

Yukimasa Watanabe

Hirofumi Kawaguchi

Jun Azuma

Ayako Yashima

Sakae Saito

Masashi Fujishima

Fumio Sugai

Yuji Tanaka

Eiichi Miyamoto

Yasuhiro Tauchi

Kazunari Hamasaki

Yasufumi Mizuta

Toshiyuki Fukami

Chikara Ishihara

Yuko Iwashita

Ichiro Yamazato

Yasuhiro Oishi

Maki Uchida

Mitsuo Ihara

Hiroaki Sakai

Hisakazu Honma

Kyoichi Nakamura

Hiroaki Iwasaki

Hideo Nakamori

Yoshio Inagaki

Junichiro Otsubo

Kazutaka Sugimoto

Nobuko Akiba

Atsushi Fujii

Akiyoshi Urano

Syunichi Matsumoto

Sakae Saitoh

Tamotsu Shimizu

Akihiro Watanabe

Susumu Hiroshima

Takashi Nagashima

Yu Sasaki

Yasuyuki Hanatani

Keisuke Oba

Daisuke Kuboshima

Kazuaki Ezure

Hisakazu Uegaito

Shyunichi Matsumoto

Kazuaki Edure

Kazuki Ezure

A developing device includes a housing, a development roller, and a roller gear. The roller gear is disposed at one axial end of the development roller and transmits a rotational drive force to the development roller. The development roller includes a sleeve and a coating layer. The coating layer is formed by dipping the sleeve in a dipping bath with the sleeve directed axially vertically. The development roller is mounted to the housing such that a lower axial end of the development roller at the time of the dipping is an opposite axial end to the one axial end at which the roller gear is disposed.

Developing device and image forming apparatus including the same

A developing device supplies a developer to a photosensitive drum, which has a cylindrical shape, and is rotatable around an axis thereof for forming an electrostatic latent image on the circumferential surface thereof. The developing device is provided with a developing roller. The developing roller is disposed to face the photosensitive drum, and has a cylindrical shape. The developing roller is rotatable around an axis thereof for carrying a developer on the circumferential surface thereof. The developing roller is provided with a small diameter portion. The small diameter portion is a part of the circumferential surface of the developing roller. The small diameter portion extends from an axial end of the developing roller axially inward by a predetermined length, and has an outer diameter smaller than an axially middle portion of the developing roller.

Developing device, and image forming apparatus provided with the same

A positively chargeable electrophotographic photosensitive member has a photosensitive layer. The photosensitive layer at least includes the following layers layered in the stated order: (I) a charge transport layer at least containing a hole transport material and a binder resin; and (II) a charge generating-and-transporting layer at least containing a charge generating material, an electron transport material, a hole transport material, and a binder resin all within this layer. The binder resin contained in the charge transport layer is different from the binder resin contained in the charge generating-and-transporting layer, and either of the binder resins contains a polyvinyl acetal resin.

Positively chargeable electrophotographic photosensitive member and image forming apparatus

The present disclosure relates to a developing roller having a conductive support base, a surface of which is covered with a resin layer, wherein the resin layer contains conductive fine particles and soluble nylon serving as a binder resin, and the resin layer surface has a surface roughness Ra of at least 0.4 &#x3bc;m, a waviness curve cycle of 50 to 400 &#x3bc;m, and a waviness curve height of 2 to 10 &#x3bc;m.

Developing roller and developing apparatus and image forming apparatus using the same

A single-layer-type electrophotographic photosensitive member includes a layer disposed on an electrically conductive substrate, the layer including at least a charge-generating material, an electron transport material, a hole transport material, and a binder resin within the same layer. The charge-generating material contains a phthalocyanine pigment and N-type pigments including at least a perylene-based pigment and an azo-based pigment, and the total amount of the N-type pigments is 0.03 to 10 parts by mass relative to 1 part by mass of the phthalocyanine pigment.

Electrophotographic photosensitive member and image forming apparatus including electrophotographic photosensitive member

Provided are an electrophotographic photoconductor which shows a small variation in sensitivity and exhibits a high sensitivity even at a small amount of light exposure and a tandem-system color image forming device provided with the electrophotographic photoconductor. A positive charging type electrophotographic photoconductor for use in a tandem-system color image forming device including a drum type electrophotographic photoconductor, a rotation speed of which is (70) rpm or more, and a color image forming device provided with the electrophotographic photoconductor, wherein, when Vb (V) denotes a sensitivity in the case where an amount of light exposure per unit area is 0.6 &#x3bc;J/cmand Va (V) denotes a sensitivity in the case where an amount of light exposure per unit area is 1.5 &#x3bc;J/cm, a sensitivity ratio represented by Vb/Va is adjusted to a value of below (2).

Electro photographic photoconductor and color image forming apparatus

The present invention provides an electrophotosensitive material comprising a conductive substrate and a photosensitive layer provided on the conductive substrate, wherein the photosensitive layer contains a polyarylate having a repeating unit represented by the general formula (1): wherein X represents a phenylene group, a naphthylene group, or a biphenylene group, as a binder resin. The polyarylate is contained in the amount of 30% by weight or more based on the entire binder resin. The electrophotosensitive material of the present invention have improved wear resistance and gas resistance while reconciling both characteristics, and thus longer life has been achieved.

Electrophotosensitive material

Disclosed are image forming apparatus [] which comprises removing a toner remained on the surface of the rotatable image carrier by cleaning means after going through developing means and transferring means; said cleaning means has an elastic blade and is contacted with the surface of the image carrier at a contact pressure within 8 to 20 g/cm, and a press-contact angle of the elastic blade of 12 to 30&#xb0;; and said image carrier is an organic photosensitive material having a photosensitive layer made of a binder resin containing an electric charge generating material and an electric charge transferring material; and image forming apparatus [], comprising a single-layer type photosensitive layer made of a binder resin containing an electric charge generating material, an electron transferring material and a hole transferring material, and the solid content of the binder resin is within 50 to 70 wt % of the whole solid content in the photosensitive layer and, a pair of paper transporting rollers are arranged on a path for transporting a transfer paper from paper feeding portion to transferring means, and a paper transporting roller at the side of the surface to be transferred among a pair of paper transporting rollers has cleaning means at the side of the surface to be transferred from the roller.

Image forming apparatus

An image forming device is disclosed which comprises an electrophotographic photoreceptor and a flash fixing means. The photoreceptor has a photoconductive layer formed on top of a support substrate, and the photoconductive layer contains a charge generating agent and a charge transport agent therein. The half maximum wavelength region of the charge transport agent's absorption peak is in a visual region that includes the wavelength region of the flash light when its intensity is 50% or greater of its maximum but does not include the wavelength region of the exposure light. This photoreceptor will not produce electrostatic irregularities even if light from the flash fixing means leaks thereon, and its sensitivity and its ability to be electrostatically charged will not decrease even if repeatedly used.

Electrophotographic photoreceptor and image forming device

A single-layer type electrophotosensitive material comprising a conductive substrate and a photosensitive layer made of a binder resin containing at least an electric charge generating material and a hole transferring material and an electron transferring material as an electric charge transferring material, which is formed on the conductive substrate, characterized in that the binder resin contains a polycarbonate resin having a repeating structural unit represented by the general formula &lsqb;1&rsqb; and the solid content of the hole transferring material and the electron transferring material is not less than 30% by weight and not more than 50% by weight relative to the entire solid content, exhibits good wear resistance with respect to the photosensitive layer and is also superior in durability.

Single-layer type electrophotosensitive material

Disclosed is a single-layer type electrophotosensitive material comprising a conductive substrate and a photosensitive layer made of a binder resin containing at least an electric charge generating material and an electric charge transferring material, which is formed on the conductive substrate, wherein an oxygen transmission rate of the binder resin is not more than 35 cc&middot;mm/m &middot;day&middot;atom, wherein it is preferred that a mobility at an electric field strength of 5&times;10 V/cm of the hole transferring material is not less than 5&times;10 cm /V/sec and a solid content of the electric charge transferring material is not less than 30% by weight and not more than 50% by weight based on the whole solid content; said electrophotosensitive material has good ozone resistance and does not cause defects such as image black belt due to lowering of the charge capability, an ozone of which is 5.0 ppm at most, and is also superior in sensitivity and wear resistance.

The present invention relates to a titanyl phthalocyanine crystal having excellent storage stability of coating solution, to satisfy that (a) the crystal does not have a peak of a change in temperature except for a peak associated with evaporation of adsorbed water in differential scanning calorimetry or that (b) the crystal recovered after dipping in an organic solvent for 24 hours at least a maximum peak at a Bragg angle 2&thgr;&plusmn;0.2&deg;&equals;27.2&deg; and has no peak at 26.2&deg; in a CuK &agr; characteristic X-ray diffraction spectrum, and a method of producing the same; and an electrophotosensitive material using the above crystal, and a method of producing the same.

Titanyl phthalocyanine crystal and production method of the same, and electrophotosensitive material and production method of the same

Disclosed are a phthalocyanine crystal in which an organic acceptor compound is associated with a phthalocyanine molecule, wherein said organic acceptor compound has a reduction potential to a reference electrode (Ag /Ag) is not less than &minus;1.5 V and not more than &minus;0.5 V, and an electrophotosensitive material containing said phthalocyanine crystal as an electric charge generating material, which exhibits sufficient photosensitivity even in high-speed image forming apparatuses.

Phthalocyanine crystal and its production, and electrophotosensitive material using the same

The present invention relates to a novel stilbene derivative, which is a stilbene compound wherein molecular structures of triphenylamino groups located at both sides of a benzene ring in a molecular center are unsymmetric, and an electrophotosensitive material having high sensitivity and improved repeatability, comprising a conductive substrate and a photosensitive layer formed on the substrate, the photosensitive layer containing the derivative.

Stilbene derivative, method of producing the same, and electrophotosensitive material using the same

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Osaka, Japan

Yukimasa Watanabe