To improve the quality of a transferred image by providing an insulating shield member for shielding a part of a discharge passing region from a transfer wire to a photoreceptor drum.

A transfer charger 25 is provided with the transfer wire 25a and a conductive shield casing 25b. The transfer wire 25a is provided in the axial direction of the photoreceptor drum 20 and generates a corona discharge for a transfer toward a copying paper P coming into contact with the periphery of the drum 20. The shield casing 25b is in a U-shape that is, opens to the periphery of the drum 20 and provided around the transfer wire 25a. A flange part 25c is formed on the side in contact with a paper guide 14, of the opening periphery of the shield casing 25b and an insulating Mylar(R) plate 15 is attached to the flange part, 25c, as the insulting shield member. The insulating Mylar(R) plate 15 shields a part of the discharge passing region from the wire 25a to the drum 20 and is operated so that the discharge passing region corresponds to only the close contact region of the drum 20 with the copying paper P.