Patent ID: 7933533

Claim:
A charging device for charging an image supporting member, comprising: a charging roller for charging the image supporting member, said charging roller having a surface, said surface having one of first irregularity and second irregularity both oriented in a first direction, said first irregularity having a first maximum peak height Rp(a) measured under a first condition having a first standard length within the following range, 10 μm<Rp ≦12 μm, an average profile length RSm within the following range, 40 μm≦RSm≦250 μm, and a ratio of a second maximum peak height Rp(b) measured under a second condition having a second standard length larger than the first standard length to the first maximum peak height Rp(a) equal to or smaller than 1.2, said second irregularity having the first maximum peak height Rp(a) within the following range, 2 μm≦Rp≦12 μm, the average profile length RSm within the following range, 200 μm≦RSm≦250 μm, and the ratio equal to or smaller than 1.2; and a cleaning member adapted to slide against the charging roller in a second direction opposite to the first direction for cleaning the surface of the charging roller.