| 摘要 |
PURPOSE:To detect the cause of image unevenneass from a position itself by detecting surface potential of a photosensitive body and image density each with sensors and judging whether operation state of an electrifying charger and a developing device is good or not, based on the detected results. CONSTITUTION:In the periphery of the photosensitive body drum 1, a surface potential sensor 4 is provided in a range X3 between an exposing point X2 from an optical system 2 and a developing range X4 of the developing device 5, and further an image density sensor 7 is provided in a range X6 between a transferring range X5 of a transferring charger 6 and a cleaning device 8. The output from the surface potential sensor 4 is compared with each reference voltage Vh and Vl at comparators 63 and 64, and output from an image density sensor 7 is compared with each reference voltage VH and HL each at comparators 61 and 62. The output from the comparators 61 to 64 are led to a CPU 60 and, as a result, since whether the operation state of the electrifying charger 3, the developing device 5, and the transferring charger 6 is good or not is judged, action can be taken by servicing persons, etc., speedily. |
