摘要 |
The size of a resonance noise due to a signal of an alternating voltage applied to a charging member (charging roller) is detected by a piezoelectric device (PZ), and in cases in which the size of the detected resonance noise (detection signal level) exceeds a predetermined size, the frequency of the alternating voltage signal applied to the charging member is shifted, by a control unit ( 50 ), by a predetermined frequency amount only.
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