An image forming apparatus and method cause a connecting/conveying device to convey a recovered toner from a cleaner part to a recovered toner housing to house therein the recovered toner, and cause a controller to control a recovered toner supply and a new toner supply in accordance with a toner concentration ratio in a developing device, which is detected by a toner concentration ratio detector, to supply the recovered toner, which is stored in the recovered toner housing, and the new toner, which is stored in the new toner housing, to the developing device. The controller separately controls the recovered toner supply and the new toner supply in accordance with the contents detected by the toner concentration ratio detecting means, to cause to change the combination of the amounts of the recovered toner and new toner to be supplied to the developing device.