| 摘要 |
PROBLEM TO BE SOLVED: To provide a developing roller free from any streak-like or band-like image defect caused by the substance oozing out from other members, and to provide an electrophotographic process cartridge and an electrophotographic image forming apparatus. SOLUTION: The developing roller in which porous inorganic particles are attached to the surface thereof includes a shaft core body, and a polyurethane resin layer formed around the shaft core body. In the developing roller, the porous inorganic fine particles has a specific surface area≥100m<SP>2</SP>/g but≤800m<SP>2</SP>/g and an average pore diameter≥5 nm but≤25 nm. If the ten-point average surface roughness of the surface of the polyurethane resin layer is Rz(μm) and the average particle diameter of the porous inorganic fine particles is P(μm), P(μm) and Rz(μm) satisfy the following relational expressions: 6≤P≤100, 0.4≤Rz≤20, and Rz+6≤P≤Rz×10+16. COPYRIGHT: (C)2009,JPO&INPIT |
