| 摘要 |
PURPOSE:To designate the exchange of a photosensitive body by measuring a residual potential so that the life of the photosensitive body may be detected and lighting an abnormality lamp when the potential gets equal to or below a reference potential. CONSTITUTION:The surface potential detected by a detector 8 is compared with the reference potential 10 by using a comparison amplifier so as to control a display lamp system 11. When the residual potential of the photosensitive body gets equal to or below the reference one, a signal showing the exchange of the photosensitive body is lighted. By exchanging the photosensitive body in accordance with the signal, a distinct image is always obtained. The photosensitive body used in this invention is obtained by forming an organic surface protective layer 16 on a photosensitive layer in which a-Si is a base. Since the exchange signal is lighted when the residual potential becomes smaller than the reference one, the photosensitive body is exchanged before the organic protective film is abraded to disappear. |
