Piezoelectric actuator and ink-jet head, and ink-jet recorder

摘要

A piezoelectric actuator is constructed by forming a common electrode 27 of Cr, a piezoelectric layer 29 of Pb(Zr,Ti)O₃, a cover layer 31 of BaTiO₃, and an individual electrode 33 of Pt in this order into a laminate. The thickness of the piezoelectric layer 29 in the lamination direction (T 1 ) and the thickness of the cover layer 31 in the lamination direction (T 2 ) satisfy the relationship of 0.08<=T 2 /T 1 <=1. The relative dielectric constant of the piezoelectric layer 29 (epsilonr 1 ) and the relative dielectric constant of the cover layer 31 (epsilonr 2 ) satisfy the relationship of epsilonr 2 /epsilonr 1>=0.2.