PURPOSE: To prevent an error of separation and a transfer defect, by impressing plural kinds of voltage of a destaticization device, and switching them according to the kind of a copying form and inpressing a voltage suitable for the copying form.

CONSTITUTION: When the copying form is relatively thick, the 1st button 11 on a console panel is pressed and then he pulse width setting circuit 13 of a switching regulator 12 outputs a pulse having relatively narror width to impress a relatively low voltage to the destaticization device 14. Consequently, the relatively thick form is separated securely. When the transfer form is thin like tracing paper, on the other hand, the 2nd botton 15 is pressed, and then the pulse width setting circuit 16 outputs a pulse with relatively wide width to impress a relatively high voltage to the destaticization device 14. Consequently, even the thin paper is destaticized sufficiently, and an error of separation and a transfer defect are prevented regardless of the kind of the copying form.