Patent ID: 6990300

Claim:
An image forming apparatus, comprising: image forming means for forming a toner image on an image bearing member; a transfer member for transferring the toner image from the image bearing member onto a transfer material by being supplied with a bias voltage; bias voltage application means for applying a normal bias voltage of a polarity opposite to a polarity of a toner or a reverse bias voltage opposite in polarity to the normal bias voltage; control means for controlling said bias voltage application means; and integral current detection means for detecting an integral of an amount of a current flowing from said bias voltage application means to said transfer member, wherein said integral current detection means is capable of detecting an integral current amount of the normal bias voltage at the time of applying the normal bias voltage and an integral current amount of the reverse bias voltage at the time of applying the reverse bias voltage, and said control means controls said bias voltage application means so that an absolute value of the integral current amount of the reverse bias voltage is in the range of not less than 0.2% and less than 25% of an absolute value of the integral current amount of the normal bias voltage.