| 摘要 |
PURPOSE:To facilitate the easy control of regist and at the same time to simplify a structure, by using one timing generating means and carrying out the control of regist with plural copying magnification ratios while the timing generating means is kept fixed. CONSTITUTION:During the real size copying, a transistor (TR) 1 is turned on by the real size signal. And a TR4 is also turned on via a resistance R1. Thus a time constant circuit is formed with a variable resistance VR1 and a capacitor C1. A time constant circuit is formed in the same way also when the copying magnification ratio is selected at a variable magnification rate of 1 or alpha. In other words, the time constant circuit is switched according to the copying magnification. A timer IC-IC1 is triggered by a timing switch SW while an optical system is scanned to start counting and to deliver an output of high potential for time T which is decided by the time constant circuit. A DEF-IC2 is set at the trailing edge of the output of the IC1 and accordingly delivers the high potential in the lapse of time T after the SW is turned on. Then a TR7 is led out, and a timing driving clutch CL is turned on to start the revolution of a timing roller. |
