| 摘要 |
PURPOSE:To always obtain stably the best picture by varying an electrification quantity and a picture exposure quantity in accordance with a use counting value of a photosensitive body. CONSTITUTION:A pulse generated by a detector 11 is counted by a counter 12 and inputted to a controller 13. A correcting quantity is derived by an electrifying characteristic drop correcting expression determined by a CPU14 in accordance with this signal. This value is connected to a high voltage power source 16 through a D/A converter 15 from the controller 13, a prescribed correcting high voltage output is outputted to an electrifier 2, and a drop of the surface potential is prevented. Also, a laser power correcting quantity is also calculated by the CPU14, and its signal reaches a laser driver 18 through the controller 13 and a D/A converter 17. As a result, as for a laser power from a semiconductor laser 3, a variation inversely proportional to a variation of a relative sensitivity of a photosensitive body 1 is given, and a sensitivity variation of the photosensitive body 1 is corrected. |
