DEVELOPING ROLLER, AND DEVELOPING DEVICE, ELECTROPHOTOGRAPHIC DEVICE AND PROCESS CARTRIDGE USING THE SAME

摘要

PROBLEM TO BE SOLVED: To provide a developing roller that can decrease the pressure to a developer between the developing roller and a developing blade, suppress sticking of the developer to the surface and suppress a stripe image defect. SOLUTION: The developing roller includes an axial core and a conductive resin layer on the surface and is characterized in that: the conductive resin layer contains low elasticity resin particles (A) and high elasticity resin particles (B) having different elasticity moduli from each other; the low elasticity resin particles (A) and the high elasticity resin particles (B) have an average particle diameter of 3μm to 30μm, and the difference (b-a) between the average particle diameter (b) of the high elasticity resin particles (B) and the average particle diameter (a) of the low elasticity resin particles (A) is 5μm to 27μm; the low elasticity resin particles (A) have an elasticity modulus of 0.05 MPa to 0.2 MPa and the high elasticity resin particles (B) have an elasticity modulus of 0.3 MPa to 2.0 MPa; and the low elasticity resin particles (A) and the high elasticity resin particles (B) are included so as to possess a cross sectional area of 10% to 50% in the cross sectional area of the conductive resin layer. COPYRIGHT: (C)2009,JPO&INPIT