Patent ID: 7483644

Claim:
An image forming apparatus comprising: an AC high voltage power supply; a DC high voltage power supply; and a high voltage power supply apparatus, which outputs an output voltage at an output end by superposing an output of said AC high voltage power supply and an output of said DC high voltage power supply, said high voltage power supply apparatus including a positive peak detector detecting a positive peak of the voltage at an output end, and a negative peak detector detecting a negative peak of the voltage at an output end, wherein an output voltage of at least one of said AC high voltage power supply and said DC high voltage power supply is controlled on the basis of the detection result of at least one of the positive peak detector and the negative peak detector, and wherein an output voltage of said AC high voltage power supply is controlled on the basis of the detection result of said positive peak detector, and an output voltage of said DC high voltage power supply is controlled on the basis of the detection result of said negative peak detector.