Patent ID: 7478898
Filing Date: 2009-01-20
Classification: B41J

Abstract:
1. An ink jet recording head unit comprising: a plurality of nozzle elements that ejects ink droplets, each nozzle element having an ink pressure chamber filling ink therein, an orifice leading to the ink pressure chamber, and a diaphragm formed as a part of the ink pressure chamber and having a first surface opposed to the ink pressure chamber, and a second surface opposite to the first surface; a plurality of piezoelectric elements provided in one-to-one correspondence with the plurality of nozzle elements, each piezoelectric element being fixed to the second surface of each diaphragm and having a positive pole and a negative pole, each piezoelectric element expanding and contracting to vary volume of the ink pressure chamber when a voltage potential difference between the positive pole and the negative pole is varied, wherein each nozzle element ejects an ink droplet from the corresponding orifice when the volume of the corresponding ink pressure chamber decreases; and a driving unit that controls expansion and contraction of each piezoelectric element, wherein the plurality of nozzle elements includes a first nozzle element and a second nozzle element adjacent to the first nozzle element, and a first piezoelectric element and a second piezoelectric element correspond to the first nozzle element and the second nozzle element respectively, wherein polarization of the first nozzle element is substantially equivalent to, but directionally opposite of the polarization of the piezoelectric element of the second nozzle element, and wherein the driving unit controls the first piezoelectric element and the second piezoelectric element to expand and contract in a complementary manner.