Sumitomo Rubber Industries Limited

Yoshihisa Mizumoto

Kenichi Kuroda

Takayuki Hattori

Mutsuki Sugimoto

Takashi Marui

Tetsuo Mizoguchi

Kei Tajima

Akihiko Kawatani

Hideyuki Okuyama

Noriaki Hitomi

Masakazu Tanaka

Hirotoshi Murakami

Kiyotaka Okuda

Naoyuki Satoyoshi

Masafumi Yamamoto

Yajun Zhang

The present invention provides an electrically conductive rubber composition of an electron conductive type which contains neither an expensive ion conductive rubber having a higher environmental dependence nor a softening agent and a liquid rubber which are liable to increase the compression set of a developing roller or contaminate a photoreceptor body, and is usable for production of a more flexible developing roller. The present invention also provides a developing roller produced by using the rubber composition. The electrically conductive rubber composition contains a rubber component including an EPDM and an NBR and/or an SBR, sulfur, a thiazole crosslinking accelerating agent, tetramethylthiuram monosulfide and tetrabutylthiuram disulfide. The developing roller () is formed from the electrically conductive rubber composition.

Electrically conductive rubber composition, and developing roller

A semiconductive roller for use as a developing roller or the like is provided, which has an outer peripheral surface at least partly imparted with a reduced friction coefficient &#x3bc; without irradiation with ultraviolet radiation. The semiconductive roller () includes a tubular body made of a crosslinking product of an electrically conductive rubber composition containing a crosslinkable rubber component, and a chloride film () formed in the outer peripheral surface () thereof through chlorination.

Semiconductive roller

A semiconductive roller is provided which includes a roller body formed from a highly extrudable rubber composition containing an SBR and an epichlorohydrin rubber in combination as a rubber component, the roller body having a higher production yield and higher toner imaging durability, and unlikely to suffer from reduction in image density due to adhesion of toner and a contact mark on an outer peripheral surface thereof with a smaller compression set. In the rubber component, the SBR and the epichlorohydrin rubber are present in an SBR excess state. In the rubber composition, a crosslinking component for crosslinking the rubber component includes a sulfur crosslinking agent and 0.75 to 3 parts by mass of a thiazole accelerating agent based on 100 parts by mass of the rubber component. The roller body () of the semiconductive roller () is made of a crosslinking product of the rubber composition.

The transfer member according to the present invention is a transfer member employed for transferring toner in an image forming apparatus utilizing electrophotography, made of a rubber composition at least containing styrene-butadiene rubber, ethylene-propylene-diene rubber and epichlorohydrin rubber as rubber components.

Transfer member

A semiconductive roller () according to the present invention has a nonporous single-layer structure formed from a rubber composition which includes: a rubber component including a styrene butadiene rubber and an epichlorohydrin rubber; and a salt of an anion having a fluoro group and a sulfonyl group in its molecule; the salt being present in the rubber composition in a proportion of 0.05 to 5 parts by mass based on 100 parts by mass of the overall rubber component.

An inventive developing roller is adapted for use in an electrophotographic image forming apparatus. The developing roller includes a roller body. At least an outer peripheral surface of the roller body is formed from a rubber composition containing a base rubber. The base rubber contains a styrene butadiene rubber in a proportion of not less than 10 mass % and not greater than 70 mass % based on the overall amount of the base rubber. The outer peripheral surface of the rubber body has a surface roughness Ra of not less than 0.78 &#x3bc;m and not greater than 1.8 &#x3bc;m.

Developing roller

The electrically conductive rubber composition contains a rubber component including an SBR, an epichlorohydrin rubber and a CR, and the proportion of the SBR is 40 to 80 parts by mass based on 100 parts by mass of the rubber component. The rubber composition further contains 1.0 to 1.5 parts by mass of a sulfur crosslinking agent, 0.2 to 0.6 parts by mass of a thiourea accelerating agent, 0.1 to 0.5 parts by mass of a thiuram accelerating agent, and 1.0 to 2.0 parts by mass of a thiazole accelerating agent based on 100 parts by mass of the rubber component.

Electrically conductive rubber composition, developing roller, and image forming apparatus

The semiconductive roller according to the present invention includes a nonporous roller body made of a rubber composition containing styrene-butadiene rubber and epichlorohydrin rubber as rubber components.

The semiconductive roller according to the present invention includes a roller body having an outer peripheral surface made of a crosslinked substance of a semiconductive rubber composition and exhibiting Shore A hardness of not more than 60, the semiconductive rubber composition contains a base polymer made of a mixture of (1) mixed rubber N of liquid nitrile rubber and solid nitrile rubber, (2) chloroprene rubber C, and (3) epichlorohydrin rubber E in a mass ratio (C+E)/N of 10/90 to 80/20, the ratios of the chloroprene rubber and the epichlorohydrin rubber in the total quantity of the base polymer are not less than 5 mass % and not less than 5 mass % respectively, and roller resistance at an applied voltage of 5 V is not less than 10&#x3a9; and not more than 10&#x3a9;.

Semiconductive roller, toner transport roller and electrophotographic apparatus

A developing roller is provided, which is particularly used in an image forming apparatus of a highly durable design and is free from toner leakage even after formation of a predetermined number of images. Opposite end regions () of an outer peripheral surface () of a roller body () of the developing roller () to be respectively kept in sliding contact with seal members each have a friction coefficient &#x3bc; of not greater than 0.15.

Developing roller for electrophotographic image forming

The present invention provides a conductive roller having a toner transport part composed of a vulcanized rubber composition at least on an outermost layer thereof. The vulcanized rubber composition contains a rubber component (A), highly conductive carbon black (B) having a particle diameter not less than 18 nm and less than 80 nm, an inorganic filler (C) consisting of not less than one kind of a metal oxide selected from among a group of titanium oxide, alumina, and silica. A total of a content of the highly conductive carbon black (B) and a content of the inorganic filler (C) for 100 parts by mass of the rubber component (A) is not less than 10 parts by mass nor more than 60 parts by mass.

Conductive roller

The semiconductive rubber composition according to the present invention contains: a rubber content containing at least copolymer rubber containing ethylene oxide as a copolymeric component and chloroprene rubber; and not less than 0.5 parts by mass and not more than 1.5 parts by mass of a thiourea-based vulcanization accelerator, not less than 0.5 parts by mass and not more than 1.5 parts by mass of a guanidine-based vulcanization accelerator and not less than 0.5 parts by mass and not more than 2.0 parts by mass of a peroxide-based crosslinking agent with respect to 100 parts by mass of the sum of the rubber content.

Semiconductive rubber composition and semiconductive rubber roller employing the same

The present invention provides a conductive roller whose outermost layer is made of a vulcanized rubber composition. The vulcanized rubber composition contains epichlorohydrin rubber and chloroprene rubber as a rubber component thereof and 0.2 to 5 parts by mass of each of a thiourea-based vulcanizing agent and a vulcanization retarder consisting of N-(cyclohexylthio)phthalimide for 100 parts by mass of the rubber component.

Conductive roller which is mounted on an image-forming mechanism of an electrophotographic apparatus

A semiconductive rubber roller comprising a toner-transporting portion whose outermost layer is formed essentially of vulcanized rubber containing 0.1 to 30 parts by mass of a phthalocyanine compound for 100 parts by mass of the vulcanized rubber. An electric resistance value of the semiconductive rubber roller which is measured at a temperature of 23&#xb0; C. and a humidity of 55% is in a range of 10to 10&#x3a9;, when a voltage of 100V is applied thereto.

Semiconductive rubber roller

A semiconductive rubber composition contains copolymerized rubber containing ethylene oxide; chloroprene rubber; and acrylonitrile-butadiene rubber. A conductive rubber roller has a conductive rubber layer composed of the semiconductive rubber composition on an outermost layer thereof.

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Kobe, Japan

Yoshihisa Mizumoto