A control device drives a main driving device among driving devices each used to discharge recording material from a recording material container. A malfunction detector detects malfunction of the main driving device. When the malfunction detector has detected the malfunction, a recording material amount setting unit sets information indicating an amount of the recording material in the recording material container connected to the main driving device to a first value. A main driving device switching unit stops, when an amount of the recording material in the recording material container connected to the main driving device is the first value, driving the main driving device and then, when the driving devices other than the main driving device include one driving device having a recording material container connected thereto that contains a recording material an amount of which exceeds the first value, switches the main driving device to the one driving device.