| 摘要 |
PURPOSE:To improve running stability of a lens unit by providing nip rollers which can nip the inside and outside surfaces of a guide rail to the lens unit at plural points. CONSTITUTION:When the operator drives a driving motor 19 by pushing a button for magnification or reduction (not shown), a lens unit 10 travels in the optical axis direction and an oscillating lever 18 oscillates along the zigzag groove cam 22 provided atop a base plate 11 so that a necessary adapter lens 16 can be set to the front face of a copying lens 15. Stopping of the lens unit at a set position is accomplished by counting the revolution of the motor by the signal for the assigned magnification as pulses with an encoder or the like and stopping the supply of electricity to the motor 19 when the count number attains the selected count number which is stored in the built-in microcomputer. |
