| 摘要 |
PURPOSE:To detect the expiration of life of a photosensitive body with a simple constitution by detecting the surface potential of an exposed part, which is exposed with a prescribed quantity of light, and that of a non-exposed part after electrifying the photosensitive body and displaying the expiration of life when the difference between detected surface potentials is smaller than a preliminarily set value. CONSTITUTION:The surface potential of the non-exposed part just before an image area of the photosensitive body uniformly electrified by an electrifying charger 2 and the surface potential of a texture part, which corresponds to the leading part having no characters, patterns, or the like of an original, in the image area are detected by a surface potential sensor 4, and results are inputted to a CPU 8, and the difference of surface potential between the non- exposed part and the exposed part (texture part) is compared with the preliminarily set value; and if the former is smaller than the latter, information indicating that the life of the photosensitive body expires is displayed on a display device 9 on an operation panel of a copying machine body. Thus, the photosensitive body is always used up to expiration of its life to avoid waste. |
