Patent ID: 6994428

Claim:
An ink-jet printing head comprising a cavity unit and an actuator which are superposed on each other, said cavity unit having (a) a plurality of nozzles open in a front surface thereof and arranged in at least one row such that said nozzles are spaced apart from each other with a predetermined spacing pitch in a direction of extension of said at least one row, (b) a plurality of pressure chambers which respectively correspond to said nozzles and which are spaced apart from each other with said predetermined spacing pitch in said direction of extension, and (c) a plurality of communication passages for communication between the respective pressure chambers and the respective nozzles, said actuator having a plurality of active portions which correspond to said plurality of pressure chambers, respectively, and which are operable to deliver the ink from the corresponding nozzles, wherein said plurality of active portions of said actuator are arranged in said direction of extension, with said predetermined spacing pitch except in a local portion of a length of said actuator in said direction of extension in which a spacing distance between two adjacent ones of said active portions in said direction of extension is larger than said predetermined spacing pitch, said plurality of pressure chambers including two groups of pressure chambers located on respective opposite sides of said local portion of the length of the actuator; and said plurality of communication passages include two groups of communication passages for communication of said first and second groups of pressure chambers with respective two groups of said nozzles of each of said at least one row, said communication passages of one of said two groups and the communication passages of the other of said two groups are inclined with respect to said front surface of said cavity unit, symmetrically with each other with respect to a plane which is perpendicular to said front surface and which includes a midpoint of said local portion of the length of said actuator in said direction of extension.