Patent ID: 7871149

Claim:
A head unit comprising: first and second heads, each having an ink ejecting face including a nozzle group, the nozzle group including a plurality of nozzle rows extending in a first direction and arranged in a second direction orthogonal to the first direction, each nozzle row including a plurality of nozzles for ejecting ink arranged along the first direction at a predetermined interval; and a holder for holding the first and second heads, wherein each of the nozzle groups of the first and second heads includes: a rectangular region in which the plurality of nozzles are arranged apart at a predetermined distance in the first direction to form a rectangular shape, and a triangular region which has one side extending in the second direction and common to one side of the corresponding rectangular region, and in which the plurality of nozzles are arranged in the first direction to form a triangular shape, wherein the first and second heads are held by the holder in parallel with each other so that the plurality of nozzles included in the rectangular regions of the first and second heads, respectively, are arranged apart at the predetermined distance in the first direction, and wherein the triangular region of the first head is overlapped with an overlapped portion of the rectangular region of the second head in the second direction, wherein the triangular region of the second head is overlapped with an overlapped portion of the rectangular region of the first head in the second direction, and wherein the plurality of the nozzles included in the triangular regions of the first and second heads and included in the overlapped portions of the rectangular regions of the first and second heads are arranged apart at the predetermined distance in the first direction.