| 摘要 |
PURPOSE:To eliminate interference to be caused by the difference of frequency, and also, to decrease the number of parts by supplying a control signal of the same frequency from the same oscillator to the PWM control part of a document exposing means and a control part for AC-boosting a developing bias. CONSTITUTION:In case of executing light quantity control of a document exposure use lamp 10 by a PWM control, a signal of the same frequency is supplied from the same oscillator to an AC boosting part 2 for boosting a developing bias 13 and a frequency of the light quantity PWM control and a frequency of the developing bias 13 are set so as to be the same. In such a way, the interference caused by the difference of the frequency can be eliminated, and since an oscillator 1 to be used is one piece, the structure is simplified and the number of parts is decreased, and the device can be miniaturized and its cost can be reduced. |
