Charging device and image forming apparatus provided therewith

摘要

An image forming apparatus has a charging member opposed to an outer circumferential surface of a rotating object to be charged. The image forming apparatus has a voltage applying section for applying a pulsating voltage Vsp between the charging member and the object to be charged. The pulsating voltage Vsp is obtained by superimposing a voltage component of a direct current on a voltage component that periodically changes. The image forming apparatus is made to satisfy a relation of Vpp<=|Vth|, where Vpp is a peak-to-peak voltage value of the pulsating voltage Vsp and Vth is a charging start voltage value of the object to be charged. The relation prevents opposite charge from being imparted to residual toner on the object to be charged.