In a printer unit, ink is poured into a storage chamber from an inlet of a tank. The storage chamber communicates with an air chamber. An air tube connects the air chamber and the outside of the tank and is opened and closed by a valve. A cover is movable to a first position in which the inlet is covered and a second position in which the inlet is exposable via a third position being a position between the first position and the second position. A valve opening/closing mechanism opens a valve when the cover is located on a side closer to the first position than the third position, and closes the valve when the cover is located between the third position and the second position. When the cover moves from the third position to the first position, a cap fits over the inlet to seal the storage chamber.