| 摘要 |
PURPOSE:To always uniformize the adsorbing state of a developer on the surface of a photosensitive body and to stabilize image density by detecting the leak current of the developer to detect the characteristic change of the developer and changing the temperature of the photosensitive body in accordance with said characteristic change. CONSTITUTION:The temperature T of the photosensitive drum 1 is controlled so as to be set up to a set temperature Tc and the temperature control is always continued during the execution of copying operation. At the execution of the copying process, the present reak current value IL of the developer is always detected by a leak current measuring circuit 10 and a temperature (t) is read out from the detected leak current value IL based on the relation stored in a ROM. The temperature (t) is set up as a set point Tc. Since the heater 3 is controlled so that the surface temperature T of the drum 1 is always set up on the set temperature Tc, the adsorbing state of the developer can be maintained at a fixed state by changing the surface temperature T of the drum 1 in accordance with the characteristic change of the developer 6c and the changing physical properties such as surface potential. |
