| 摘要 |
PURPOSE:To obtain a satisfactory image whose image density is less varied, by controlling the surface potential of an image carrier based on the surface potential detection signal outputted from a surface potential detecting means in the case of the detecting a specified position of the image carrier by a position detecting means. CONSTITUTION:An annular colored zone consisting of a black colored zone covering concentrically almost whole peripheral surface of a photosensitive drum 8 with one side face of the drum 8 and a white colored part connected to said black colored zone covering only a slight peripheral surface part is formed on one side face of the drum 8. A rotational position detecting mechanism 200 is provided which detects the white colored part during the rotation of the photosensitive drum 8 to output the detection signal, and the surface potential of the photosensitive drum 8 detected by a surface potentiometer 210 is read when this rotational position detecting mechanism 200 detects the white colored part. Thus, the surface potential detection position of the photosensitive drum 8 is specified to control the surface potential mode precisely. |
