| 摘要 |
PURPOSE:To accurately control an actual scanning by providing a correcting means which corrects the target value of the rotating speed of a driving motor for scanning on the basis of a scanning speed detection signal from a scanning speed detecting means. CONSTITUTION:An encoder 21 fitted onto the rotating shaft of a motor 1 sends pulses proportional to the rotating speed to a phase comparator 22. Further, the phase comparator 22 is applied with pulses from a frequency divider 23 to calculate the phase difference between both pulses (phie and phiN). The signal based on the phase difference between the pulse frequencies phie and phiN is input ted to and filtered by a low-pass filter 26, further amplified by an amplifier 27, and then sent to a motor 1, whose rotating speed is controlled. If the actual scanning speed is different from the normal rotating speed of the motor owing to an error in the transmission of the driving system of this control system, the frequency division ratio N which is the target value of the rotating speed of the motor is corrected so that correct control is performed. Consequently, the scanning speed is corrected to the normal speed all the time. |
