Patent ID: 7462146

Claim:
A charging roller member comprising a mandrel and a conductive elastic layer therearound; said charging roller member having a surface roughness Rz jis 94 of from 0.5 μm to 10 μm; and said conductive elastic layer containing voids in the vicinity of its surface, said voids being empty space appearing on the cut surface of said conductive elastic layer when said elastic layer is cut in the direction that falls at a right angle with said mandrel, wherein substantially all of said voids have an average internal diameter of from 10 μm to 400 μm and an aspect ratio of from 1.3 or more to 10.0 or less, and have an angle of from 0° or more to 45° or less, said angle being an acute angle between an axis that takes the maximum internal diameter of each of said voids and a tangent to a concentric circle of the roller member at the center of each of said voids.