| 摘要 |
PURPOSE:To always obtain a stable good image by forming the image in an optimum condition even in the case an environment undergoes a sudden change. CONSTITUTION:A voltage is impressed on an electrostatic charging roller 2 which is brought into contact with a photoreceptor drum 1 so as to uniformly charge the surface of the photoreceptor drum l at a prescribed voltage. The resistance of the electrostatic charging roller 2 changes in accordance with the temperature, so that the voltage impressed on the electrostatic charging roller 2 is decided by executing the optimization control so that the charged voltage may be kept constant. When a power is supplied, the temperature is detected by a temperature detecting sensor 41, and the temperature T0 is stored by a control part 45. Thereafter, when the temperature T undergoes a drastical change and ¦T-T0¦>=DELTAT is obtained, the optimization control is executed again. The image quality is stabilized even in the case the environment undergoes a remarkable change, and also, it is unnecessary to frequently execute the optimization control. |
