Patent ID: 6341205
Filing Date: 2002-01-22
Classification: G03G

Abstract:
An image forming apparatus comprising:a belt-like image carrier which holds a visible image formed of a charged colorant and is circularly moved; a transfer roll which is disposed to be brought into press contact with a front surface of the image carrier through a recording medium and collectively transfers the visible image on the image carrier onto the recording medium; a backup roll which is disposed opposite to the transfer roll to be brought into press contact with a rear surface of the belt-like image carrier and forms a transfer nip region of a predetermined width with the transfer roll; and a transfer bias application part which applies a transfer bias voltage to at least one of the backup roll and the transfer roll; wherein a cleaning bias voltage having a polarity opposite to the transfer bias voltage is applied to at least one of the backup roll and the transfer roll, and an output value of the cleaning bias voltage is controlled so that a potential difference between the belt-like image carrier and the transfer roll becomes optimum for cleaning and the output value of the cleaning bias voltage is controlled according to a system resistance between the backup roll and the transfer roll.