| 摘要 |
PROBLEM TO BE SOLVED: To properly apply a voltage to a charger or properly convey a recording medium by detecting the sound discharged from the charger, and controlling the applied voltage to the charger based on the output. SOLUTION: A sound sensor 16 serving as a sound detecting means detecting the discharge sound of a split charger 4b is provided toward the inside of the split charger 4b near the opening section of the split charger 4b on the opposite side to a photoreceptor drum 7. When the AC voltage of 1 kHz, for example, is applied to the split charger 4b, positive/negative discharges are repeated at the cycle of 1 kHz mainly between a wire 4b1 and a shield 4b2, fine vibrations of the wire 4b1 are generated at 1 kHz by the discharges, and a discharge sound is generated. The sound is detected by the sound sensor 16. A control means connected to the sound sensor 16 detects the discharge state and discharge stop time of the split charger 4b, classifies the degree of a leakage based on the discharge stop time, and controls the peak-to-peak voltage of a separating AC power supply 13. |
