| 摘要 |
PURPOSE:To provide a copying machine capable of reducing the useless adhesion of toner to a non-image part at the time of starting and finishing copying even in the case of using a photosensitive body where the potential of an exposure part is varied because of electrostatic fatigue. CONSTITUTION:A resistor 8 having a specified resistance value is connected in parallel with a Zener diode 6a functioning as a constant-voltage generating means and a capacitor 7. After an electrostatic charger 2 is stopped at the time of finishing copying, the charge of the capacitor 7 is discharged through the resistor 8 in a very short time. It is conceivable to short-circuit the diode 6a and the capacitor 7 when a current flowing in the diode 6a after the charger 2 is stopped is lower than a Zener current Iz. It is also conceivable to change the set value of the potential of the conductive base of a photosensitive belt 1 by the constant-voltage generating means 6 based on the detected result of the surface potential of the photosensitive body at the time of finishing copying or starting copying operation. Then, it is also conceivable to control developing bias voltage so that developing current Id at the time of developing in the non-image part may be a current for an area where toner adhesion amount on the photosensitive body is the smallest. |
