Patent ID: 8657421

Claim:
An image forming apparatus comprising: a recording head having nozzles to eject droplets of liquid; a liquid tank removably mounted to the image forming apparatus to store liquid to be supplied to the recording head; a head tank mounted on the recording head to store the liquid supplied from the liquid tank and supply the liquid to the recording head; a flexible film disposed at a side face of the head tank and deformable in response to a change in pressure of the liquid within the head tank; a liquid supply passage connecting the liquid tank to the head tank; a liquid intake port formed in the head tank, through which the liquid supplied from the liquid tank flows into the head tank via the liquid supply passage; a valve member disposed in the head tank to open and close the liquid intake port; the valve member having a hole disposed therein; a lock lever disposed in the head tank and movable with deformation of the flexible film; and a stopper disposed in the head tank to prevent misregistration of the lock lever, wherein when the flexible film inflates, one end of the lock lever engages the hole of the valve member and the valve member becomes immovable by the stopper to form a locked state in which the valve member is not openable and closable, and when the flexible film contracts, the one end of the lock lever disengages from the hole of the valve member and the valve member becomes movable to form an unlocked state, wherein the lock lever is provided distinctly from the valve member, and the lock lever does not move in conjunction with movement of the valve member, wherein in the unlocked state in which the lock lever is not engaged in the hole of the valve member, the valve member is movable regardless and independent of the lock lever to open and close the liquid intake port, and in the locked state in which the one end of the lock lever is engaged in the hole of the valve member, the valve member is fixed with the lock lever to be immovable, wherein in each of the locked state and the unlocked state, displacement of the flexible film is not transmitted to the valve member via the lock lever, and the flexible film and the lock lever are used only for operation of locking or unlocking the movement of the valve member, and wherein, in the unlocked state, the valve member opens and closes the liquid intake port in response to a change in the pressure of the liquid within the head tank to regulate a flow of the liquid into the head tank.