PURPOSE: To improve the separating capacity of a transfer paper, by discriminating the density of a picture by the current value of a developing bias power source to change the voltage of a high voltage power source applied to a separating charger.
CONSTITUTION: The current flowed to a developing bias power source 8 is detected by a resistance R to discharge a capacitor C through a switch SW1 by a voltage-current converting circuit 14. Simultaneously, a charging circuit 15 is operated, and the capacitor is charged through a switch SW1', and a potential VC due to the charge of the capacitor C becomes a value related to the constant of the voltage-current converting circuit 14 or the like, and the voltage VC of the capacitor is changed by a developing bias current (i). A voltage VH of a variable voltage power source 16 is changed in accordance with this voltage VC' and the high voltage VH of the output of the variable high voltage power source 16 is lowered to a voltage VHO when the leading edge of a paper 9 is separated, and the paper 9 is separated by its own weight thereafter.
OONISHI HAJIME
KURAMOTO AKIMASA
| JPS56104363A | 1981-08-20 |