Abstract: A head unit has a supply tank provided above a plurality of heads, for storing ink and a collecting part having an internal space into which ink flows from the plurality of heads. In the head unit, a plurality of ink inlet pipes serving as a plurality of passages leading from the supply tank to the plurality of heads have the same shape and the same resistance and a plurality of ink outlet pipes serving as a plurality of passages from the plurality of heads to the collecting part have the same shape and the same resistance. This equalizes respective flow rates of ink and respective pressures of ink at nozzles in the plurality of heads. As a result, it is possible to suppress variation in landing positions and the like of ink with respect to the nozzles among the plurality of heads.

Abstract: A printer comprises a head having a plurality of outlets, a first ink tank connected to the head and a second ink tank storing ink, and the second ink tank is connected to the first ink tank via a supply line and connected to the head via a return line. The supply line is provided with a pump for supplying the first ink tank with ink stored in the second ink tank. A main decompressor connected to the second ink tank decompresses the inside of the second ink tank to a negative pressure and ink is returned from the first ink tank to the second ink tank through a passage leading from the first ink tank to the second ink tank via the head. This allows an appropriate circulation of ink while degassing the ink in the second ink tank.

Abstract: A head unit has a supply tank provided above a plurality of heads, for storing ink and a collecting part having an internal space into which ink flows from the plurality of heads. In the head unit, a plurality of ink inlet pipes serving as a plurality of passages leading from the supply tank to the plurality of heads have the same shape and the same resistance and a plurality of ink outlet pipes serving as a plurality of passages from the plurality of heads to the collecting part have the same shape and the same resistance. This equalizes respective flow rates of ink and respective pressures of ink at nozzles in the plurality of heads. As a result, it is possible to suppress variation in landing positions and the like of ink with respect to the nozzles among the plurality of heads.