Image forming apparatus and process cartridge

摘要

An image forming apparatus including an image bearing member, a charging device including a charging member, which uniformly charges the surface of the image bearing member by applying a charging bias in which an AC voltage is overlapped with a DC voltage to the charging member, an image formation speed switching device to switch from one image formation speed to another image formation speed among multiple image formation speeds by changing a surface traveling speed of the image bearing member according to a particular switching condition, a storage device to store a charging current target of the charging bias applied to the charging member for each of the multiple image formation speeds, an electric current detection device to detect an electric current flown through the charging member and an AC voltage adjustment device to adjust an AC voltage of the charging bias applied to the charging member such that the electric current detected by the electric current detection device approaches the charging current target stored at the storage device which corresponds to the image formation speed when the electric current is detected. With regard to at least two image formation speeds among the multiple image speeds, the charging current target is set for each of the at least two image formation speeds such that each AC voltage adjusted by the AC voltage adjustment device is substantially the same.