| 摘要 |
PURPOSE:To prevent deterioration of image quality from a partial deficiency in light quantity when rising of lighting of an exposure lamp is delayed in the process of second piece onward when a repeated copying operation is carried out. CONSTITUTION:The actual light quantity of the lamp is detected by a sensor, and when there is a deficiency in the light quantity, the developing bias is compensated only for the tip part of the image. In one mode, developing bias voltage at the period of compensation is made to be a fixed value, and adjustment of the compensation period is made according to the quantity of deficiency of the detected light quantity. In another mode, the combination of the bias voltage value at the time of compensation and the period of compensation is adjusted according to the detected quantity of deficiency of the light quantity. The quantity of the bias compensation is made gradually smaller along with the lapse of time. Reference value for the light quantity is the light quantity detected in the first copying cycle. |
