Patent ID: 8602533

Claim:
An ink jet head comprising: an ink supply path supplied with ink from an ink inlet port; an ink discharge path configured to discharge the ink to an ink discharge port; an ink chamber provided to communicate with the ink supply path and the ink discharge path, and having a nozzle configured to discharge the ink; and a piezoelectric actuator operable to apply pressure to the ink within the ink chamber by displacement of a vibrating plate of the ink chamber, wherein the piezoelectric actuator is arranged on an island member and the island member is arranged on the vibrating plate of the ink chamber, the island member is disposed to extend between the ink supply path and the ink discharge path, a length W 1 of a side of the island member on the ink supply path side is shorter than a length L that extends from the ink supply path side to the ink discharge path side, wherein the length W 1 is longer than a length W 2 of a side of the island member on the ink discharge path side, and wherein a relationship between the length W 1 of the side of the island member on the ink supply path side and the length W 2 of the side of the island member on the ink discharge path side is represented by: d/ 4 <W ( W 1 ,W 2)≦ d wherein d is a length of a side of the piezoelectric actuator on the ink supply path side.