| 摘要 |
PURPOSE:To keep surface potential of an image carrier at the time of continuous copying within a fixed range and to improve picture quality by detecting charge characteristic of the image carrier and controlling a charging device according to the result of detection. CONSTITUTION:Fatigue characteristic 10a is encoded and recorded magnetically on the side end of a photosensitive body drum 10 being an image carrier. A magnetic head 12 is provided at a position opposite to the side end of the drum 10, and the head detects the characteristic 10a and inputs to a controlling device 11 provided with a microcomputer 11a. The device 11 controls impressed voltage of a high tension transformer 13 that impresses voltage to the charger 13a of a charging device 13 by a driver 11b following command of the computer 11a. Impressed voltage value of the transformer 13b for the number of continuous copying is set in the computer 11a according to fatigue characteristic of the photosensitive body, and every time specified number of continuous copying is reached, the impressed voltage of the transformer 13b is reset, and the surface potential of the drum 10 is maintained within a fixed range. |
