PURPOSE: To obtain the latent images faithful to an original by performing exposure in the state that the turning of a photoreceptor is forcibly stopped by using a braking means.

CONSTITUTION: A friction piece 9 of a slender plate shape is positioned near the outside circumference of a stationary roller 2 and its lower end part is secured to a supporting block 10. The shaft 11 projecting integrally with this supporting block 10 is pivotally supported to an immobile member and is secured at its shaft end part to the root end part of a lever 12. The other end part of the lever 12 is pivotally supported to one end of a link 13 and the other end of this link 13 is pivotally supported to the plunger 14a of a solenoid 14. Here, as the solenoid 14 is also fixed to the immobile member; therefore, the friction piece 9 is oscillated around the shaft 11 according to the in and out operations of the plunger 14a so that it presses a photoreceptor 1 to the stationary roller 2 or releases the pressing state.