Patent ID: 8831450
Filing Date: 2014-09-09
Classification: G03G

Abstract:
1. An image forming apparatus comprising: a rotatable image bearing member; a first charging member for electrically charging said image bearing member at a first charging portion by being supplied with a first DC voltage; a second charging member provided downstream of the first charging portion with respect to a rotational direction of said image bearing member, said second charging member electrically charging said image bearing member, charged by said first charging member, at a second charging portion by being supplied with an oscillating voltage in the form of a second DC voltage biased with an AC voltage; a toner image forming portion, provided downstream of the second charging portion and upstream of the first charging portion with respect to the rotational direction of said image bearing member, for forming a toner image on a surface of said image bearing member charged by said first charging member and said second charging member; a current detecting portion for detecting a DC current passing through said second charging member; and a controller for controlling a voltage value of the second DC voltage on the basis of the DC current detected by said current detecting portion when the first DC voltage is applied to said first charging member and the second DC voltage is applied to said second charging member, wherein said controller controls the voltage value of the second DC voltage so that an absolute value of the DC current detected by said current detecting portion is smaller than a predetermined value.