Multi-nozzle ink jet head
View Patent ↗A multi-nozzle ink jet head having a diaphragm that effectively utilizes the force generated by thin-film piezoelectric elements is disclosed. The head ( 2 ) has a head substrate ( 28 ) in which are formed a plurality of nozzles ( 39 ) and a plurality of pressure chambers ( 29 ), a multi-layer diaphragm ( 23 - 1, 23 - 2 ), piezoelectric elements ( 27 ), and individual electrodes ( 26 ). By making the thickness of the common electrode layer ( 23 - 1 ) of the multi-layer diaphragm be thin but such that problems do not occur during multi-pin driving, optimization of the rigid layer becomes possible, and hence it is possible to use the force generated by the thin-film piezoelectric elements efficiently in ink ejection.
1. A multi-nozzle ink jet head which is manufactured by a thin film formation technique and has a plurality of nozzles, the multi-nozzle ink jet head comprising:
a head substrate in which the plurality of nozzles and a plurality of pressure chambers are formed;
a diaphragm that comprises a common electrode layer and a rigid layer and covers each of the plurality of pressure chambers;
a plurality of piezoelectric elements provided on the diaphragm in correspondence with the pressure chambers; and
a plurality of individual electrodes provided on the piezoelectric elements in correspondence with the piezoelectric elements,
wherein the common electrode layer has a thickness so as to have a resistance value such that a lag in a rise time of a driving waveform when driving all of the piezoelectric elements relative to a rise time of a driving waveform when driving a single one of the piezoelectric elements, is not greater than 50 ns.
2. A multi-nozzle ink jet head which is manufactured by a thin film formation technique and has a plurality of nozzles, the multi-nozzle ink jet head comprising:
a head substrate in which the plurality of nozzles and a plurality of pressure chambers are formed;
a diaphragm that comprises a common electrode layer and a rigid layer and covers each of the plurality of pressure chambers;
a plurality of piezoelectric elements provided on the diaphragm in correspondence with the pressure chambers; and
a plurality of individual electrodes provided on the piezoelectric elements in correspondence with the piezoelectric elements,
wherein the common electrode layer has a minimum thickness of thicknesses of the common electrode layer selected from a range such that a lag in a rise time of a driving waveform when driving all of the piezoelectric elements relative to a rise time of a driving waveform when driving a single one of the piezoelectric elements results in a positional shift of not more than half a dot of a recorded dot formed by a minimum ink amount flying.