| 摘要 |
PURPOSE:To provide a method for preventing toner sticking (fogging) to the low potential part of a photosensitive body and the lowering of density in a high potential part caused by environmental change and the deterioration, etc., of developer and the photosensitive body and for easily correcting the deterioration of a copied image. CONSTITUTION:Developing of plural kinds of reference density marks 1 which are installed on an original platen glass 2 in the shaft direction or rotational direction of the photosensitive body 8 with two or more kinds of respective density within the extent of chemical density 0.8-0.9 is performed by varying a developing bias, and then, it is detected by one or plural image density sensors 9 which are installed in the shaft direction of the photosensitive body 8, and then, judged by a CPU circuit 12, each circuit of an exposure circuit 10 and a high voltage power supply 11 is controlled, and an exposure voltage, the developing bias voltage and a grid bias voltage are varied, so that the optimum image density can be obtained. |
