Abstract: 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 roller 10 comprises a shaft 1, an elastic layer 2 supported on the periphery of the shaft and one surface layer 3 formed on the peripheral surface of the elastic layer 2. The elastic layer 2 is 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 3. 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.

Abstract: A developing roller which shows an excellent environmental performance and is free from occurrence of toner filming and toner leakage is provided. The developing roller 10 comprises a shaft 1, an elastic layer 2 supported on the outer periphery of the shaft 1, and a single surface layer 3 formed on the outer peripheral surface of the elastic layer 2. The elastic layer 2 comprises a polyurethane foam and the surface layer 3 comprises 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.

Abstract: 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 roller 10 comprises a shaft 1, an elastic layer 2 supported on the periphery of the shaft and one surface layer 3 formed on the peripheral surface of the elastic layer 2. The elastic layer 2 is 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 3. 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.

Abstract: A developing roller which shows an excellent environmental performance and is free from occurrence of toner filming and toner leakage is provided. The developing roller 10 comprises a shaft 1, an elastic layer 2 supported on the outer periphery of the shaft 1, and a single surface layer 3 formed on the outer peripheral surface of the elastic layer 2. The elastic layer 2 comprises a polyurethane foam and the surface layer 3 comprises 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.

Abstract: 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.

Abstract: 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.

Abstract: A composition for synthetic resin magnets (such as magnet rollers for electrophotography process) which is composed of a resin binder and a magnetic powder mixed and dispersed therein. The resin compound has improved melt flow rate because the binder contains a thermoplastic and an aliphatic polyamide. Owing to its improved melt flow rate, the resin compound can be incorporated with a large amount of magnetic powder without deterioration in moldability. Thus the resulting plastic magnet has a strong magnetic force. In addition, the composition for synthetic resin magnets may be incorporated with a hindered phenol antioxidant, so that it is molded at a higher temperature (120-180° C.) than usual to achieve the same object as mentioned above.

Abstract: A composition for synthetic resin magnets (such as magnet rollers for electrophotography process) which is composed of a resin binder and a magnetic powder mixed and dispersed therein. The resin compound has improved melt flow rate because the binder contains a thermoplastic and an aliphatic polyamide. Owing to its improved melt flow rate, the resin compound can be incorporated with a large amount of magnetic powder without deterioration in moldability. Thus the resulting plastic magnet has a strong magnetic force. In addition, the composition for synthetic resin magnets may be incorporated with a hindered phenol antioxidant, so that it is molded at a higher temperature (120-180° C.) than usual to achieve the same object as mentioned above.

Abstract: A resin composition for a resin magnet includes a resin binder containing a thermoplastic resin as a main component and a polymerized fatty acid based polyamide elastomer: and a magnetic powder mixed and dispersed in said resin binder. The resin composition further contains an ultra fine powder of an inorganic filler having a particle size of 1 &mgr;m or less. A process of producing pellets of a resin composition for a resin magnet, includes the steps of: mixing pellets of a binder resin with a magnetic powder on a batch processing basis; supplying the mixture to a kneading-extruder by means of a counting feeder; and extrusion-molding the mixture, to obtain pellets of a molding material for a resin magnet, in which the magnetic powder is mixed and dispersed in the binder resin.