| 摘要 |
PURPOSE:To perform high speed recording at a low noise level and to enhance durability by performing closed loop control by a detection means for detecting the angle-of-rotation position of the rotor of a stepping motor and controlling a current by the modulation of a pulse width at the time of initial processing driven by the closed loop control. CONSTITUTION:An MPU 20 counts the output pulse 27 of an encoder 26 constituted of a detection disk 17 and a photointerruptor 18 to detect the position of a carriage 2. Further, the MPU 20 controls the rotational speed of a carriage driving motor 1 by a motor driving circuit 25 through a pulse width modulation (PWM) signal generator 23 and also controls the starting, stoppage and rotary direction of the carriage driving motor 1 by the motor driving circuit 5 through a current change-over circuit 24 for changing over the exciting currents of coils 15a, 15b by a closed loop control system. That is, the MPU 20 compares the present speed with a predetermined indicated rotational speed to output a speed control signal 29 and a PWM signal generator 23 generates a pulse signal 30 of the duty ratio corresponding to said signal 29. |
