PROBLEM TO BE SOLVED: To prevent a piezoelectric element that varies the volume of a fluid chamber of a fluid injection device from being damaged by the application of a tensile force thereto.SOLUTION: The piezoelectric element that varies the volume of the fluid chamber is secured at an end opposite to the fluid chamber and has a movable member provided at the other end on the side of the fluid chamber, the movable member being moved as the piezoelectric element expands. A magnetic force (magnetic attraction or magnetic repulsion) is applied to the movable member to bias the piezoelectric element in a direction to press against a fixed member. In this way, when a force in a pulling direction is generated on the piezoelectric element, the force receives the magnetic force and a tensile force actually working on the piezoelectric element is reduced, whereby the piezoelectric element can be prevented from being damaged by the action of the tensile force.COPYRIGHT: (C)2012,JPO&INPIT【課題】流体噴射装置の流体室の容積を変動させる圧電素子に対して引張力が作用することによる破損を防止する。【解決手段】流体室の容積を変動させる圧電素子は、流体室とは反対側の端部を固定し、かつ、流体室側の端部には、圧電素子の伸長に伴って移動する可動部材を設ける。この可動部材に対して磁力(磁気吸引力または磁気反発力)を作用させることにより、圧電素子を固定部材に押し付ける方向に付勢する。こうすれば、圧電素子に対して引張方向の力が発生したときには、その力を磁力が受けて、圧電素子に実際に作用する引張力を軽減するので、引張力の作用による圧電素子の破損を防止することができる。【選択図】図2
