BELT MEMBER, TRANSFER UNIT INCORPORATING SAME, IMAGE FORMING APPARATUS INCORPORATING SAME, AND METHOD OF EVALUATING SAME

摘要

A multi-layer endless belt member with a high-resistance surface layer for use in an image forming apparatus. A volume resistivity thereof ranges from approximately 8.0 to approximately 11.0 in log[Omega.cm]. An amount of resistivity change of a first surface thereof is greater than an amount of resistivity change of a second surface thereof by 0.05 or greater in log [Omega/square], where the amount of resistivity change of the first surface indicates a difference between surface resistivity values measured after a given voltage is applied for 1 second and for 100 seconds on the first surface thereof and the amount of resistivity change of the second surface indicates a difference between surface resistivity values measured after a given voltage is applied for 1 second and for 100 seconds on the second surface thereof.