An image forming apparatus includes a recording head, a liquid tank, a first passage, a second passage, a pressure unit, and a control valve. The first passage is connected to the head to supply liquid to the head. The second passage is connected to the tank. The pressure unit is disposed at the second passage to apply pressure to liquid in the second passage. The control valve includes an internal channel to connect the first and second passages, an expandable liquid retaining chamber connected to the internal channel to retain the liquid, and a valve member disposed in the internal channel to open and close the first and second passages and movable by a flow of liquid from the chamber to the first passage created by ejection of liquid from the head to communicate the second passage with the first passage.