Image forming apparatus with cleaning bias feature

摘要

There is provided an image forming apparatus capable of finely cleaning a transfer roll at all times by regulating the relation between a mechanical adhesion force of toner to the surface of the transfer roll and a mechanical adhesion force of toner to the surface of an image carrier with which the transfer roll comes in press contact. At the time of cleaning the transfer roll, both the electrostatic adhesion force and the mechanical adhesion force of charged colorant to the surface of the belt-like image carrier are set larger than the electrostatic adhesion force and the mechanical adhesion force of charged colorant to the surface of the transfer roll.