PURPOSE: To increase the life of a transfer assist blade.

CONSTITUTION: When the leading edge of copying paper is detected in the entrance of a transfer station D, a cam 84 is rotated by the operation or actuation of a motor, and by rotating a part of a lobe thereby made independent, the cam is brought into contact with a transfer assist blade 82. For example, a sensor as a light sensitive device detects the entry of the leading edge of the copying paper in the transfer station and transmits a signal through a control circuitry to a stepper motor. The stepper motor is then actuated, a specified cam lobe corresponding to the width dimension of the copying paper is placed to be in contact with the transfer assist blade 82 and, by rotating a camshaft so as to distort the transfer assist blade 82 in contact with the back surface of the copying paper, the copying paper is pressed to a developed toner powder image on an optical conductive belt 10.