| 摘要 |
PURPOSE:To control inversion adequately in a min. time and to move a scanning system and a photoreceptor relatively with ease and high accuracy by running a DC motor for scanning backward in a prescribed position according to the size of a cassette and a variable magnification. CONSTITUTION:A DC motor M2 is run forward with a DC amplifier 34 and transistors (TRs) 35-1, 35-2 by the H signal of the forward signal FAW from a microcomputer 30, whereby scanning is accomplished. A CV37 divides down the pulse train E1 from an encoder 36 according to the data m1 on the frequency dividing ratio from the microcomputer 30 and converts the same to the pulse train E2 of the same frequency as a clock frequency CLK. The E2 and the CLK are compared in a PLL32 and the speed of the motor M2 is controlled with the amplifier 34. A main motor M1 is controlled similarly. When the FAW goes to an L and a backward signal BAW to an H according to the size of the cassette and the m1, the TRs 35-1, 35-2 turn off and 35-3, 35-4 turn on, by which the motor M2 is run backward and the scanning system and the photoreceptor are moved relatively with high accuracy. |
