US Patent 7815293 Ink-jet head and method of producing the same

An ink-jet head, including: a flow-passage unit having a laminated structure with a plurality of plates and including a plurality of nozzles, a common ink chamber, and a plurality of individual ink flow-passages each of which communicates the common ink chamber with a corresponding one of the plurality of nozzles and in each of which a pressure chamber having an opening open in a surface of the flow-passage unit is provided; and an actuator fixed to the surface of the flow-passage unit so as to close the opening of the pressure chamber and operable to change a volume thereof, wherein the plurality of plates include an outermost plate nearest to the actuator and at least one plate contiguous to the outermost plate, wherein the pressure chamber is formed by a plurality of pressure-chamber-forming holes respectively provided in the outermost plate and the at least one plate so as to communicate with each other, and wherein the outermost plate has a smallest thickness among the plurality of plates.