Patent ID: 7255429

Claim:
An inkjet print head comprising a cavity unit and an actuator unit which are superposed on each other, wherein said cavity unit defines (a) a plurality of nozzles which are open in a nozzle opening surface of said cavity unit and which are arranged in at least one row, (b) a plurality of pressure chambers which are positioned in vicinity of said actuator unit and which are arranged in at least one row so as to be held in communication with the respective nozzles, and (c) at least one common chamber which stores an ink supplied from an ink supply source and refills said pressure chambers, wherein said actuator unit has a plurality of active portions which correspond to said pressure chambers, respectively, and which are selectively operable to eject the ink through the respective nozzles, wherein each of said at least one common chamber is elongated in a direction substantially parallel with a corresponding one of said at least one row of said pressure chambers, such that said plurality of pressure chambers arranged in the corresponding one of said at least one row overlap said each of said at least one common chamber as viewed in a direction perpendicular to said nozzle opening surface of said cavity unit, wherein said each common chamber is shaped such that at least one of said plurality of pressure chambers arranged in the corresponding row overlaps said each common chamber differently from the other of said plurality of pressure chambers arranged in the corresponding row, wherein said cavity unit further defines at least one open-space chamber which is located between said pressure chambers and said at least one common chamber in said direction perpendicular to said nozzle opening surface of said cavity unit, and which is isolated from said pressure chambers and said at least one common chamber, and wherein any one of said at least one open-space chamber overlaps all of said plurality of pressure chambers arranged in a corresponding one of said at least one row, as viewed in said direction perpendicular to said nozzle opening surface of said cavity unit, such that all of said pressure chambers arranged in any one of said at least one row overlap a corresponding one of said at least one open-space chamber substantially equally with each other.