Patent ID: 7156505
Filing Date: 2007-01-02
Classification: B41J

Abstract:
1. An apparatus for ejecting, from a nozzle communicating with a pressure chamber in which a liquid is accommodated, a droplet of the liquid by deforming a portion of a piezoelectric body and thereby changing a volume of the pressure chamber, the apparatus comprising: the piezoelectric body; at least one first internal electrode which is provided in the piezoelectric body, at first position where the first internal electrode is opposed to the pressure chamber in a first direction; at least one second internal electrode which is provided in the piezoelectric body, at a second position distant from the first position in a second direction perpendicular to the first direction; and a first polarizing electrode and a second polarizing electrode which cooperate with each other to sandwich, in the first direction, at least a first portion of the piezoelectric body that is located between the first and second internal electrodes in the second direction, the first portion of the piezoelectric body being polarized in the first direction by applying a polarizing voltage to the first and second polarizing electrodes, one of the first and second polarizing electrodes being conductively connected to one of the first and second internal electrodes, wherein when a driving voltage is applied to the first and second internal electrodes, a first electric field is produced in the first portion of the piezoelectric body, substantially in the second direction, and a second electric field is produced in a second portion of the piezoelectric body that is located between said one of the first and second polarizing electrodes and the other of the first and second internal electrodes, substantially in the first direction.