| 摘要 |
PROBLEM TO BE SOLVED: To provide a developing roller having small residual strain and enabling image quality to be enhanced. SOLUTION: The columnar developing roller is constituted of an elastic layer composed of an urethane foaming body, a middle layer arranged on the outer peripheral surface of the elastic layer and a surface layer arranged on the outer peripheral surface of the middle layer, wherein the middle layer has a residual strain of≤2%. It is desirable that the Asker C hardness of the developing roller is≤60°. It is desirable that the thickness of the middle layer is 10 to 500μm, and it is desirable that the volume resistance value of the surface layer is≤10<SP>9</SP>Ωcm and the center line average roughness (Ra) thereof is 0.1 to 2.0μm. COPYRIGHT: (C)2006,JPO&NCIPI |
