| 摘要 |
PROBLEM TO BE SOLVED: To provide a development device for image formation which will not deteriorate the charging properties of toner by preventing field concentration due to surface roughness, is free from filming phenomenon on the surface of a toner bearing member, even on a long-term basis, and is superior in toner transport properties, as well as in image uniformity. SOLUTION: The development device for color image formation comprises the toner bearing member, wherein the toner bearing member comprises: a conductive elastic roller core of which the surface is roughened so as to have ruggedness; and a ceramic covering layer disposed on the roughened surface of the elastic roller core, having a specific resistance of≤1×10<SP>-6</SP>Ωcm, and also having a resistance lower than that of the elastic roller core, wherein the thickness (t<SB>1</SB>) of the ceramic covering layer on projected portions in the elastic roller core surface is made smaller than the thickness (t<SB>2</SB>) of the ceramic-covering layer on recessed portions. COPYRIGHT: (C)2007,JPO&INPIT |
