| 摘要 |
PROBLEM TO BE SOLVED: To restrain utterance of unusual noises at the time of rotation of the developing roller pressed into contact with an electrostatic latent image holding drum in the developing device of the electrophotographic apparatus, especially, even in the case of a high peripheral speed of 30-100mm/sec. SOLUTION: This developing roller 1 is obtained by laminating a conductive elastic layer 3 and a surface layer 4 coaxially on the periphery of a rotary axis 2, and the surface layer 4 is made of a polyurethane resin containing a silicone-acrylic copolymer capable of holding the developer on the surface. This developing roller 1 is pressed into contact with the electrostatic latent image holding drum face to face and this roller is rotated at a higher revolution speed than the drum. This surface layer 4 is composed essentially of the polyurethane resin having a stress of 20-70kgf/cm<2> at the time of 100% elongation, and containing the silicone-acrylic copolymer in an amount of 0.2-30weight% and an electric resistance of 10<3> -10<10>Ω.cm. It is preferred that the peripheral speed of the roller is 30-100mm/sec, and it is higher than that of the latent image holding drum. |
