IMAGE FORMING APPARATUS ROTATIONALLY DRIVING IMAGE BEARING MEMBER AND CONTACT ELECTRIFYING MEMBER OF PROCESS CARTRIDGE AND PROCESS CARTRIDGE COMPRISING IMAGE BEARING MEMBER AND CONTACT ELECTRIFYING MEMBER

A cartridge is provided in which an electrifying roller is driven in a counter direction to photosensitive member drum and which has a toner remaining amount detector and a memory, and the electrifying roller is driven by an electrifying roller drive motor. The electrifying roller optimum rotation speed stored in the memory in advance is accessed when the toner remaining amount reaches a predetermined value, and the electrifying roller rotation speed is changed in accordance with the electrifying roller optimum rotation speed. The accumulated distance by which the photosensitive member drum and the electrifying roller abrasively slide is written in the memory, and when the toner remaining amount reaches a predetermined value, the electrifying roller optimum rotation speed corresponding to the abrasive sliding distance is accessed. The electrifying roller rotation speed is changed in accordance with the electrifying roller optimum rotation speed.