Sumitomo Rubber Industries Limited

Takashi Marui

Yoshihisa Mizumoto

Kei Tajima

Kenichi Kuroda

Akihiko Kawatani

Noriaki Hitomi

Hideyuki Okuyama

Masakazu Tanaka

Takeshi Ishimaru

Kiyotaka Okuda

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.

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.

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.

A developing roller is provided which is capable of forming a toner layer having the most uniform possible thickness on an outer peripheral surface of a roller body thereof. The roller body () of the developing roller () is formed from a rubber composition comprising: a base rubber which is a mixture comprising NBR and/or SBR, CR and an epichlorohydrin rubber; and not less than 2.5 parts by mass and not greater than 15 parts by mass of a tackiness imparting agent based on 100 parts by mass of the base rubber.

Developing roller

The semiconductive roller according to the present invention includes: a roller body having an outer peripheral surface made of a semiconductive rubber composition; and an oxide film covering the outer peripheral surface of the roller body, while the semiconductive rubber composition contains a base polymer and a crosslinking component for crosslinking the base polymer, the base polymer is a mixture of a bicopolymer E containing epichlorohydrin and nitrile-butadiene rubber N, the mass ratio E/N of the bicopolymer E and the nitrile-butadiene rubber N in the mixture is 50/50 to 80/20, and the crosslinking component includes a thiourea-based crosslinking component for crosslinking the bicopolymer E and a sulfur-based vulcanizing component for vulcanizing the nitrile-butadiene rubber N.

Semiconductive roller, charging roller and electrophotographic apparatus

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

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

A conductive roller has a core and a conductive foam formed on a peripheral surface thereof. The conductive foam constitutes a three-phase rubber composition containing 35 to 50 parts by mass of epichlorohydrin rubber, 25 to 35 parts by mass of ethylene-propylene-diene copolymer rubber, and 25 to 30 parts by mass of acrylonitrile-butadiene rubber as a rubber component thereof. The conductive foam does not have a coating layer formed on a surface thereof. The conductive roller has an Asker C hardness, an electric resistance value, an average surface-cell diameter, and a number of surface cells set to 30 to 36&#xb0;, 10to 10&#x3a9;, 100 to 200 &#x3bc;m, and 50 to 120/1.5 mm square respectively.

Conductive roller

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.

Growing community of inventors

Kobe, Japan

Takashi Marui