| 摘要 |
PROBLEM TO BE SOLVED: To provide a power unit that prevents an image carrier and a discharge member constituting an image forming apparatus from deteriorating and decreasing in printing quality. SOLUTION: The power unit 100-1 has a triangular wave generator 11 which generates a triangular wave having the same period with a PWM signal period, a smoothing circuit 12 which generates a smoothed signal by smoothing the PWM signal, a comparator 13 which generates a rectangular wave signal rising and falling alternately in timing where the voltage value of the triangular wave signal and the mean voltage value of the smoothed signal become equal to each other, and an inverting circuit 14 which inverts and outputs the rectangular wave signal, and varies a DC voltage supplied to a charging roll 50 according to the duty ratio of the rectangular wave signal after inversion which is output from the inverting circuit 14. COPYRIGHT: (C)2007,JPO&INPIT
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