Patent ID: 7801461

Claim:
A charging member cleaning roller comprising: a core body; and an elastic layer that is provided on a peripheral surface of the core body and comprises a urethane foam having an open-cell structure, a resilience of 15% to 30%, and a hardness of 150N to 230N, wherein the resilience is a ratio of a maximum height of rebound of a steel ball dropped from a height of 500 mm onto a top face of a first test piece, to a drop height of 500 mm, wherein the steel ball has a diameter of 16 mm and a weight of 16 g, and the first test piece has been cut out of the urethane foam and has a size of 50×100×100 mm or more; and wherein the hardness is a load applied to a second test piece, and is obtained by applying a first load by vertically pushing the second test piece such that a thickness of the second test piece becomes 75% of an initial thickness of the second test piece, immediately removing the first load, then applying, and maintaining for 20 seconds, a second load by vertically pushing the second test piece such that the thickness of the second test piece becomes 25% of the initial thickness of the second test piece, and then measuring the value of the second load, wherein the second test piece has a size of 50×380×380 mm.