A toner image of an original document is formed on a photoconductive drum (1) and transferred onto a copy sheet (4) which is moved into contact with the drum (1) by a corona charging unit (5) which applies an electrostatic charge to the copy sheet (4) causing the toner image to be transferred thereto. The copy sheet (4) is separated from the drum (1) by a conductive belt (6). The belt (6) is initially grounded so that the leading edge of the copy sheet (4) is attracted thereto by induced electrostatic charge. A voltage of the same polarity as the transfer charge is then applied to the belt (6) to prevent transfer of the toner image back to the drum (1).