| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a method for forming a ceramic layer having high performance and adjustable electric characteristics on an electrostatic charging roller. <P>SOLUTION: The ceramic layer 16 is formed on a roller core body 14 by performing plasma spray coating of a blend composed of an insulating ceramic material and a semiconductive ceramic material. Further the ceramic layer 16 has a selected RC circuit time constant related to electric response of the ceramic layer 16 to voltage difference applied between the electrostatic charging roller core body and a charged region adjacent to an outer surface of the roller. A charge donor roller for an electrophotographic copying machine is constituted of the cylindrical roller core body, an adhering layer 15 and the ceramic layer 16. The ceramic layer 16 is formed by performing plasma spray coating of the blend which is composed of the insulating ceramic material and the semicondcutive ceramic material and is selected in order to adjust the RC circuit time constant of the ceramic layer 16 corresponding to the applied voltage difference. In order to be protected from humidity pollution the ceramic layer 16 is sealed by a hermetically sealing agent (seal coat) 17 such as wax manufactured by Carnauba Co. <P>COPYRIGHT: (C)2003,JPO |
