PURPOSE: To improve the accuracy for positioning, by providing a means which is coupled to a motor and generates clock pulses and a means which receives said clock pulses and calculates the number of pulses corresponding to the distance between reference positions.
CONSTITUTION: A copying machine is so constituted that a changeover circuit 11 for forward and backward runs of a motor and a changeover circuit 12 for high and low speeds of the motor are controlled by a microcomputer 13 to drive a DC motor 1 and a zoom lens is moved and stopped up to the reference position corresponding to an assigned magnification at the speed corresponding to the moving distance thereof. The control part calculates the number of the clock pulses corresponding to the moving distance of the zoom lens from the difference between the number of the clock pulses corresponding to the current position and the number of the clock pulses corresponding to the assigned magnification. The accuracy for positioning is made higher than the accuracy in the prior art according to the above-mentioned constitution.
TOMOSADA MASAHIRO
HIROSE MASAYUKI
MIYATA MASANORI
KOMIYA YUTAKA
