| 摘要 |
PURPOSE:To enable to smoothly transfer to equal speed control irrespective of the speed locus after starting of a drive motor by discriminating the magnitude of the rotating speed of the motor when the motor transfer from starting to equal speed control and controlling an input timing circuit based on the speed. CONSTITUTION:A scanning drive motor 8 for a copying machine or the like is driven through a phase comparator 1, a charge pump circuit 2 and a loop filter 3, and a switch SW is switched by a switching circuit 5 after starting, thereby transferring to an equal speed control. At this time a circuit 10 which discriminates whether the rotating speed of the motor 8 at the transferring time is larger than the specified speed or not is provided, thereby controlling an input timing controller 14 in response to the result, and previously inputting one of the reference pulse or rotating synchronizing pulse to the signal of a phase comparator 1 prior to the other. Accordingly, the equal speed control can be always smoothly transferred irrespectively of the speed locus or the transfer timing until the equal speed control is started. |
