| 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 determining the inversion position for scanning determined beforehand in accordance with the size of a cassette and a variable magnification. CONSTITUTION:A 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. In the stage of changing a magnification, 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 a pulse train E2 of the same frequency as a clock frequency CLK. A PLL32 compares the E2 and the CLK, outputs a voltage and controls the speed of the motor M2 with a DC 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 on and the motor M2 is run backward, whereby the scanning system and the photoreceptor are moved relatively with high accuracy. |
