| 摘要 |
PURPOSE:To prevent the density irregularity of an image or the width irregularity of a line from occurring by executing the constant-voltage control of an electrostatic of an electrostatic charge member with the aid of a DC voltage detected when the electrostatic charge member corresponds to the image forming area of a body to be electrostatically charged. CONSTITUTION:An electrostatic charge roller 2 is controlled in terms of a DC constant- current control in a rotating term that it corresponds to the non-images forming area surface of a drum 1. Then, the DC voltage at this time is detected. When the DC constant-voltage control is started, the image forming of a firs sheet by laser scanning and exposure is executed. Besides, the electrostatic charge roller 2 corresponds t the image forming area surface of the drum 1 and the surface of the drum 1 is electrostatically charged under a DC constant-voltage control state. Therefore, the electrostatic potential of the drum 1 is made to be fixed regardless of the variation of the resistance of the roller 2. As the result, even when the roller 2 and a pin hole on the surface of the drum 1 are brought into contact with each other at the time of forming an image, the DC voltage with respect to the roller 2 is not changed because it is not the constant-current control. Thus, the irregularity of the density does not occur at the contact time of the roller with the pin hole. |
