Patent ID: 7306328

Claim:
An ink jet printer head, comprising: a cavity unit having a plurality of ink ejection nozzles arranged in at least one array, and a plurality of pressure chambers arranged in at least one array and communicating with the ink ejection nozzles, respectively; and an actuator having a plurality of active portions each of which is driven to change a pressure of an ink accommodated in a corresponding one of the pressure chambers, and thereby eject, from a corresponding one of the ink ejection nozzles, a droplet of the ink, wherein the cavity unit and the actuator are stacked on each other, wherein the cavity unit is constituted by a plurality of sheet members which are stacked on each other and which include a base sheet having the pressure chambers; at least one manifold sheet which has at least one manifold chamber storing the ink supplied from an ink supply source and delivering the ink to each of the pressure chambers, at a location where said at least one manifold chamber is at least partly opposed to said each pressure chamber in a direction of stacking of the sheet members; at least one spacer sheet which is interposed between the base sheet and said at least one manifold sheet; and a nozzle sheet having the ink ejection nozzles communicating with the pressure chambers, wherein said at least one spacer sheet is more rigid than each of the sheet members other than said at least one spacer sheet, and wherein said at least one spacer sheet has a thickness of from about 300 μm to about 500 μm, and each of at least the base sheet and said at least one manifold sheet has a thickness of from about 50 μm to about 150 μm.