a piezoelectric substrate grinding step of grinding a lower surface of the piezoelectric substrate, the lower surface being opposite to {TAIL ~ an upper surface} on which the ejection grooves and {HEAD ~ the non ejection grooves} are formed, to allow the non ejection grooves to penetrate the piezoelectric substrate from the upper surface through the lower surface thereof 
on are formed
a piezoelectric substrate grinding step of grinding a lower surface of the piezoelectric substrate , the lower surface being opposite to { TAIL ~ an upper surface } on which the ejection grooves and { HEAD ~ the non ejection grooves } are formed , to allow the non ejection grooves to penetrate the piezoelectric substrate from the upper surface through the lower surface thereof
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL REL OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL REL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH