PURPOSE: To enable vibrations and noise of the device to be prevented without impairing scanning speed by providing the means of controlling the driving force of a reciprocating means for exposure scanning so that the reciprocating means is driven at a low acceleration speed at the starting of backward movement after exposure scanning.
CONSTITUTION: As current is supplied to an electromagnetic clutch 12, a drive pulley 5 is driven to start exposure scanning. At this same instant, a braking gear 13 is driven. On the other hand, a brake drum 15 is revolved by way of a rotary clutch 14 to act braking power upon the drive pulley 5. Hence, the electromagnetic clutch 12 assumes a half-clutch state, as a result of which the driving power of the initial stage of driving becomes smaller than that in a steady driving state, thus it is accelerated at a lower acceleration rate snd the vibrations are small and are rapidly converged in a short approach section. In the backward movement, the one- way rotating clutch 14 disengages and therefore the brake drum 15 does not rotate.
TOOYAMA YOSHIKUNI
ISHIDA MASAHITO
MIYAMOTO KOUICHI
