DEVELOPMENT ROLL

PROBLEM TO BE SOLVED: To provide a development roll capable of obtaining a good image while securing a uniform toner conveying amont and suppressing occurrence of uneven density and image roughness. SOLUTION: The three-layer structure developing roll is constituted by forming a base layer 2 on the outer peripheral surface of a shaft body 1 with silicone rubber, forming an intermediate layer 3 on the outer peripheral surface of the base layer 2, further, forming a surface layer 4 on the outer peripheral surface of the intermediate layer 3. And, the surface layer 4 is formed by using conductive composition containing the following components (A) to (D); (A) urethane materials, (B) conductive agent, (C) silicone acrylic grafted resin having a low molecular weight, (D) mixture of fine particles (d1) and (d2), where the mixture ratio in weight of (d1) to (d2) is set within the extent of (d1)/(d2)=0.24 to 0.67, (d1) denotes a large-sized particle having an average particle diameter of 10 to 14μm, (d2) denotes a small-sized particle having an average particle diameter of 3 to 5μm. COPYRIGHT: (C)2006,JPO&NCIPI