| 摘要 |
PROBLEM TO BE SOLVED: To form a compact piezoelectric actuator 20 for an ink jet head having four nozzle arrays. SOLUTION: Elongated discrete electrodes 24a, 24b, 24c and 24d are formed along a nozzle array at positions corresponding to respective pressure chambers 16a-16d in a cavity plate 9 on the wide surface of a piezoelectric sheet 21 wherein the discrete electrodes 24a and 24d in the first and fourth arrays are arranged, respectively, on the side close to the edge of a pair of long sides of each piezoelectric sheet 21 and connected with first short lead-out electrodes 26a, respectively. The discrete electrodes 24b and 24c in the second and third arrays are arranged in the widthwise central part of each piezoelectric sheet 21 and connected with second long lead-out electrodes 26b extending to the opposite sides. The trunk part 25a of a common electrode to be laid in layer overlaps the discrete electrodes 24b and 24c in the second and third arrays in the plan view and the branch part 25b overlaps the discrete electrodes 24a and 24d in the first and fourth arrays in the plan view.
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