Patent ID: 7711278

Claim:
An image forming apparatus comprising: a rotatable image bearing member; a charge eliminating device eliminating an electric charge of the image bearing member; a charging member disposed on a downstream side of the charge eliminating device in a rotation direction of the image bearing member, and charging the image bearing member, the charging member charging a charge eliminating operation area of the image bearing member where the charge eliminating device is operated; an electric current detecting portion detecting an electric current passing through the charging member, wherein at a time of non-image formation, a voltage is applied to the charging member in the charge eliminating operation area to detect a value of an electric current passing through the charging member by the electric current detecting portion; and a control portion, which switches, based on the electric current value, between a constant-current-control and a constant-voltage-control of the voltage to be applied to the charging member at a time of image formation wherein when the electric current value is not more than a first value, the control portion performs the constant-voltage-control of the voltage to be applied to the charging member at the time of image formation, and wherein when the electric current value is more than the first value, the control portion performs the constant-current-control of the voltage to be applied to the charging member at the time of image formation.