PURPOSE: To prevent scattering of a developer to hold a good charging state, by charging the surface of a transfer material with a prescribed polarity before the transfer material is led to the surface of a photosensitive drum and providing a guide means which leads the transfer material.

CONSTITUTION: Before transfer on a photosensitive drum 1, the electric charge having a polarity opposite to that of a developer is given to a transfer material by a corona discharger 3. A conductive roller 6 is so grounded that it functions as the counter electrode of a corona discharger 3, and the rear face of the transfer material is charged with the same polarity as the corona discharge polarity, which is given to the front face, by an insulating layer 5 on the outside circumference of the roller 6. A conductive rubber roller 7 functions to neutralize the opposite-polarity charge which is induced on the surface of the insulating layer 5 by friction. A feed roller 8 and a leading guide 9 are insulated from peripheral parts so as to prevent the escape of the charge given to the transfer material. Thus, the developer on the photosensitive drum is transferred well to the transfer material.