| 摘要 |
PURPOSE:To improve the developing characteristic by detecting an abnormal operation, and to raise the safety of a device by detecting a number of revolution of a driving motor of a developing device of a copying machine, etc., varying the torque in accordance with a variation of the number of revolution, and controlling the number of revolution. CONSTITUTION:A developing device 6 is driven by a motor 1, and its number of revolution is inputted to an encoder 2. Subsequently, a signal from the encoder 2 is inputted to a one shot multivibrator 4. When the number of revolution becomes low, as for an output Q of the vibrator 4, the duty of LOW becomes small, and the level is varied in the higher direction than a mean value. Therefore, the speed is controlled by enlarging an output duty of a pulse width modulator 3 and applying a large torque to the motor 1. Also, the set number of revolution of the motor 1 is controlled by the torque. Accordingly, an abnormality of the number of revolution of the motor, which is caused due to a fact that the developing device is not installed yet, and a supply quantity of a toner is abnormal is detected by a detector 9 and displayed 8, therefore, the safety of an apparatus can be secured. |
