Patent ID: 7815292

Claim:
A liquid ejection head, comprising: a nozzle through which liquid is ejected; a pressure chamber which contains the liquid and connects to the nozzle; a piezoelectric body which changes volume of the pressure chamber to generate pressure for ejecting the liquid in the pressure chamber through the nozzle; a spacer member which forms a space allowing the piezoelectric body to be displaced; and an electrical connection member which connects the piezoelectric body with a substrate having a wire, the electrical connection member being provided inside the space, wherein the following formula is satisfied: σ min ×L/δL min ≦E≦σ max ×L/δL max , where a range from σ min through σ max represents a range of a pressing force when the piezoelectric body and the substrate is connected via the electrical connection member, L represents a thickness of the spacer member, a range from δL min through δL max represents a range of an amount of compressive deformation of the spacer member when the pressing force is applied within the range of the pressing force, and E represents a Young's modulus of the spacer member, wherein σ min is 0.5 MPa, σ max is 50 MPa, δL min is 1 μm, and δL max is 15 μm.