An image forming apparatus includes an image forming unit and a control unit to control the image forming unit to start a preparatory operation after a first instruction has been received from a controller and start an image forming operation when the preparatory operation is complete and a second instruction is received from the controller. In a first mode, when the first instruction has been received, the preparatory operation is started before the second instruction is received, and in a second mode, when the first instruction has been received, the preparatory operation is not started until the second instruction is received. In the first mode, the operation mode is switched from the first mode to the second mode based on information pertaining to the number of jobs in which the image forming operation has been started in response to the second instruction after the preparatory mode has been completed.