| 摘要 |
PURPOSE:To prevent a platen from vibrating in a copying machine by generatively braking a motor prior to the start of reverse rotation brake, and then reverse braking while limiting the current flowed to the motor within the prescribed value. CONSTITUTION:A platen 1 reciprocates by the rotation of a shaft 3 of a motor 2, and the rotating direction is controlled by the ON and OFF of transistors (TR)4-1-4-4. The current flowed to the motor 2 is detected by a current detecting resistor 21, and a constant-current limiter 22 outputs a current limit signal when the detected current is the prescribed value or lower. When the platen 1 reaches the vicinity of the home position in the rear half of the reciprocating motion, only the TR4-2 is turned ON, a closed circuit in which the armature resistance of the motor 2 and the diode connected in parallel with the TR4-2 is formed, and the motor 2 is generatively braked. Then, reverse brake is performed, and constant current control is achieved at this time. In this manner, the platen 1 can be smoothly stopped. |
