Abstract: An ink jet recording head unit includes: at least one nozzle array in which a plurality of nozzle openings are arrayed; a plurality of common ink chambers, each adapted to store ink to be ejected; compliance parts provided to wall surfaces defining the common ink chambers, respectively; and a plurality of ink flow passages which supply ink from ink supplying sources through the common ink chambers to the nozzle openings. Of the plurality of the ink flow passages, an ink flow passage shorter than another ink flow passage has the compliance part of the common ink chamber, which is located at a middle of the ink flow passage and which is set smaller in comparison to the other ink flow passage.

Abstract: An ink jet recording head unit includes: at least one nozzle array in which a plurality of nozzle openings are arrayed; a plurality of common ink chambers, each adapted to store ink to be ejected; compliance parts provided to wall surfaces defining the common ink chambers, respectively; and a plurality of ink flow passages which supply ink from ink supplying sources through the common ink chambers to the nozzle openings. Of the plurality of the ink flow passages, an ink flow passage longer than another ink flow passage has the compliance part of the common ink chamber, which is located at a middle of the ink flow passage and which is set smaller in comparison to the other ink flow passage.