A rubber blade cleaning system is widely used in electrophotography process to remove residual toner particles on the photoreceptor surface. In the cleaning process, wear of the photoreceptor is observed by mechanical friction with a rubber cleaning blade. On the other hand, the photoreceptor surface is refreshed by the wear and this prevents image degradation when an aged photoreceptor is used. To obtain both longer life of the photoreceptor and higher image quality, it is important not only to reduce the wear rate of the photoreceptor but also to reduce the variation in the wear rate depending on image forming conditions. In this study, the wear mechanism was investigated from the points of behaviors of a rubber blade, toner particles and additives near cleaning nip. Numerical simulation using FEM (Finite Element Method) structural analysis and DEM (Distinct Element Method) particle motion calculation were used to understand these behaviors. It was clarified that the wear of the photoreceptor mainly was caused by deposited additives released from toner surfaces and that the fluidization of toner particles affects the deposited mass of additives strongly. Based on the results, a remarkable reduction in wear variation was achieved by optimization of cleaning parameters.