| 摘要 |
PURPOSE:To prevent a copy image from expanding or shrinking owing to variation in the frequency of a commercial power source and to take a proper copy at all times by detecting the frequency variation of the commercial power source and correcting the rotating speed of a DC motor according to the frequency variation. CONSTITUTION:An AC motor 2 is supplied with commercial electric power through a transformer 4 and an AC motor control circuit 5, which is controlled by a microcomputer 9 to control the rotation and stop of the AC motor 2. The commercial electric power obtained through a transformer 6 is converted by a DC motor power circuit 7 into DC power, which is supplied to a DC motor 3 through a DC motor control circuit 8, which receives a control signal from the microcomputer 9 to control the rotation and stop of the DC motor 3 and also controls its rotating speed. Consequently, even if the AC power source varies in frequency, the speed of a photosensitive body, etc., matches with the speed of an exposure scanning system at any time, and a copy image neither expands nor shrinks, thereby obtaining a proper copy image.
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