Bridgestone Corporation

Takayuki Sugimura

Masato Yoshikawa

Hirotaka Tagawa

Koji Takagi

Kenichi Miyazaki

Shinichi Toyosawa

Yasuo Horikawa

Taichi Kobayashi

Kota Kawano

Hiroyuki Anzai

Hikaru Ishikawa

Yoshinori Iwabuchi

Junji Sakata

Hideo Sugiyama

Shingo Ohno

Shuyou Akama

Hiroyuki Kanesugi

Kouta Kawano

Takuro Sugimoto

A developing roller in which the decay rate of the surface potential is high and in which an image failure caused by the accumulation of electric charge does not occur is provided. The developing rollerincludes a shaft, an elastic layersupported on the outer periphery of the shaft, and at least one coating layerformed on the outer periphery of the elastic layer. The volume resistivity of a layer on the inner periphery side of the elastic layer and the coating layer is smaller than the volume resistivity of a layer on the outer periphery side, and the difference between the volume resistivities of the elastic layer and the coating layer positioned on the outermost periphery side is in the range of 2.8 to 4.3 (Log &#x3a9;cm).

Developing roller

An electrically conductive roller which may easily obtain a desired surface roughness, and which has good setting property without problems such as high cost and compression set is provided. An electrically conductive rollercomprises a shaft, an elastic layersupported on the periphery of the shaft and one surface layerformed on the peripheral surface of the elastic layer. The elastic layeris composed of a urethane foam in which the degree of swelling is not more than 120% with respect to the solvent used in the formation of the surface layer. The urethane foam preferably contains, as a polyol component, a polyester polyol having a hydroxyl value of 200 to 400 and 3 or more functional groups.

Electrically conductive roller

There is a developing roller having a low compression permanent strain without contaminating a photosensitive drum and deteriorating toners. The developing rollercomprises a shaft, an elastic layerformed on an outer periphery of the shaftand a surface coating layerformed on an outer peripheral face of the elastic layer, in which the surface coating layercomprises a urethane resin formed by crosslinking a lactone-modified polyol with a polyisocyanate. The urethane resin is preferable to be formed by crosslinking the lactone-modified polyol with two or more kinds of polyisocyanates.

Developing roller and imaging apparatus comprising the same

A developing roller which shows an excellent environmental performance and is free from occurrence of toner filming and toner leakage is provided. The developing rollercomprises a shaft, an elastic layersupported on the outer periphery of the shaft, and a single surface layerformed on the outer peripheral surface of the elastic layer. The elastic layercomprises a polyurethane foam and the surface layercomprises an aqueous polyurethane resin as a major component and further a water-dispersible silica and/or an aqueous silicone acrylic graft polymer. As the aqueous polyurethane resin, a UV curing resin may be preferably used.

Developing roller comprising surface layer containing water-dispersible silica and/or aqueous silicone acrylic graft polymer

A conductive roller such as a developing roller, a charging roller or the like provided with a resin coating layer on a surface of an elastic layer, and more particularly to a conductive roller having the resin coating layer using an ultraviolet-curing type resin or an electron beam curing type resin and being obtained by contriving a structure of the resin coating layer, rendering the resin coating layer to contain microparticles, controlling the particle size of the microparticles, or forming the resin coating layer after the outer peripheral surface of the elastic layer is subjected to surface treatment.

Developing roller, charging roller, conductive roller and method for producing the same

A development roller is provided which can ensure a desired surface roughness and roller hardness even when an elastic layer has not sufficient solvent resistance and which can be preferably used for a long period of time without generating any peeling of a coating film during a continuous long operation. In the development roller, an underlying conductive layer having at least one sublayer and a surface resin layer are provided on the elastic layer in that order. The elastic layer is formed of a foam material having a closed cell structure, the underlying conductive layer is formed from a water-based paint containing a conductive agent, and one of the sublayers of the underlying conductive layer that is in contact with the elastic layer is at least primarily composed of a chloroprene-methacrylic acid copolymer.

Development roller

Growing community of inventors

Yokohama, Japan

Takayuki Sugimura