| 摘要 |
PURPOSE:To always obtain an image having a desired picture quality by providing a means for controlling automatically the operating state of an image forming means in accordance with the detected value of a parameter, and a means for selecting manually whether an automatic control means is to be operated or not at the time of executing the image forming means. CONSTITUTION:The surface potential of a part of the surface of a drum 47 to which the light beam of a blank exposure lamp 70 is projected is measured as a bright part surface potential, and the surface potential of a part of the surface of the drum 47 to which the light beam of the blank exposure lamp is not projected is measured as a dark part surface potential. First of all, the value of the bright part potential and the dark part potential which can obtain a correct image contrast is set as a target value. The correction of a difference of the bright part potential and a correction of a difference of the dark part potential are executed by an AC electrifier and a primary electrifier, respectively, and whether the surface potential reaches the target value by a control of once or not is not known due to the variation of the atmosphere, deterioration of the electrifier, etc., therefore, when the device is in a prescribed state, the surface potential is measured plural times, and the control of an output of a corona discharge device is also executed by the same times as the measurement. |
