| 摘要 |
PROBLEM TO BE SOLVED: To obtain a rubber roll capable of uniformly electrifying toner, is excellent in toner carrying performance and capable of forming an image excellent in balance between dot reproducibility and printing density by constituting the roll with a rubber layer having the specified values of center line average roughness in an axial direction, ten-point average roughness in the axial direction, and the ratio of ten-point average roughness in a circumferential direction to ten-point average roughness in the axial direction. SOLUTION: This rubber roll is constituted of a columnar core bar consisting of a conductive regid body and a rubber layer laminated on the outer peripheral surface of the core bar. As for the outer peripheral surface of the rubber layer; the center line average roughness in the axial direction is 0.3-2.5μm, the ten-point average roughness in the axial direction is 6-10μm, and the ratio of the ten-point average roughness in the circumferential direction to the ten-point average roughness in the axial direction is 0.9-1.2. When this ratio becomes large, the printing density becomes high but the dot reproducibility is lowered. When the ratio becomes small, the printing density and the dot reproducibility are lowered. In order to make the outer peripheral surface of the rubber layer have such surface roughness, the rubber layer is ground by dry grinding and then ground by wet grinding. |
