An image forming apparatus includes an image carrier that carries a developer image formed by a developer including external additives, a charging member for charging the image carrier, a developer carrier that carries the developer, a developer supply member to which a supply voltage is applied for supplying the developer to the developer carrier, a main controller that controls an image formation mode for developing the developer image and controls a cleaning sequence mode for cleaning the charging member, and a voltage controller that changes outputs of the charging voltage, the development voltage and the supply voltage, and executes the cleaning sequence mode based on instructions of the main controller. When executing the cleaning sequence mode, the voltage controller makes an absolute value of the charging voltage larger than that in the image forming mode, and afterwards sets the output of the charging voltage to an OFF state.