Patent ID: 8668314

Claim:
An image forming apparatus comprising: a recording head having nozzles to eject liquid droplets; a liquid tank detachably mounted to the image forming apparatus to store liquid to be supplied to the recording head; a first passage connected to the recording head to supply the liquid to the recording head; a second passage connected to the liquid tank; a pressure unit disposed at the second passage to apply pressure to liquid in the second passage; and a control valve disposed between the first passage and the second passage to control supply of the liquid from the second passage to the first passage, the control valve including an outflow port communicated with the first passage, an inflow port communicated with the second passage, an internal channel to connect the first passage and the second passage, 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 passage and the second passage and movable by a flow of liquid from the liquid retaining chamber to the first passage created by ejection of liquid from the recording head to communicate the second passage with the first passage, wherein a capacity of the expandable liquid retaining chamber is reduced by ejection of the liquid droplets from the recording head, and wherein the valve member is disposed within the internal channel, with a clearance between the valve member and the internal channel, the valve member is configured to be reciprocally movable to close the outflow port and to close the inflow port, and movement of the valve member to a position at which the valve member does not close any of the outflow port and the inflow port creates a flow of the liquid from the inflow port to the outflow port via the clearance.