| 摘要 |
PURPOSE:To snychronize the rotation of a photoreceptor with the operation of an optical system sufficiently, by detecting the rotational speed of the photoreceptor, setting the pulse rate of a pulse motor on the basis of the detection output, and then driving the pulse motor. CONSTITUTION:An FF circuit 43 is set by the 1st pulse from the sensor 42 of a photoreceptor 27 and pulses of a lock pulse signal T1 are counted by a countter 45. When the photoreceptor 27 rotates by one turn and the sensor 42 generates a next pulse, the counted value n1 is read in an arithmetic circuit 46. The circuit 46 calculates the value of n2=t1Xn1/t2XN where N is the number of steps of a pulse motor 40 which corresponds to the one-turn surface distance of the photoreceptor 27 and t2 is the period of a basic clock pulse T2, and the calculated value is set in a counter 47. Consequently, the energizing of an energizing switching circuit 48 is switched at a period t2Xn2 and the motor 40 is driven. Therefore, the rotational speed of the photoreceptor 27, even when varies, is synchronized sufficiently with the moving speed of an optical system. |
