Liquid droplet discharge head, liquid droplet discharge apparatus, and method for producing liquid droplet discharge head

A liquid droplet discharge head which discharges liquid droplets of a liquid onto a medium, the liquid droplet discharge head comprising:

• a channel unit which is formed with a plurality of pressure chambers and a plurality of nozzles communicated with the pressure chambers, respectively;
• a piezoelectric actuator which is arranged on the channel unit to cover the pressure chambers and which selectively applies a pressure to the liquid in the pressure chambers to discharge the liquid therefrom, the piezoelectric actuator including:
• a piezoelectric layer which has first active portions corresponding to central portions of the pressure chambers and second active portions corresponding to portions surrounding the central portions of the pressure chambers;
• a first constant electric potential electrode which is arranged on the first active portions;
• a second constant electric potential electrode which is arranged on the second active portions;
• and
• individual electrodes which are arranged to face the first and second constant electric potential electrodes, the first active portions being arranged between the individual electrodes and the first constant electric potential electrodes, and the second active portions being arranged between the individual electrodes and the second constant electric potential electrodes;
• and
• a wiring structure which is connected to the piezoelectric actuator, the wiring structure including:
• a wiring board;
• a driver IC which is provided on the wiring board and which applies a driving electric potential to the individual electrodes;
• and
• lines which are provided on the wiring board, the lines including individual lines through each of which the driving electric potential from the driver IC is supplied to one of the individual electrodes, a power line through which an electric power is supplied to the driver IC, a ground line through which a ground electric potential is supplied to the driver IC, a first constant electric potential line through which a first constant electric potential is applied to the first constant electric potential electrode, a second constant electric potential line through which a second constant electric potential is applied to the second constant electric potential electrode, a first short circuit portion which short-circuits the power line and the first constant electric potential line, and a second short circuit portion which short-circuits the ground line and the second constant electric potential line,
• wherein the first and second active portions are deformed respectively so that the first and second active portions are elongated in a first direction directed toward the pressure chamber and the first and second active portions are shrunk in a second direction perpendicular to the first direction under a condition that the driving electric potential is applied to the individual electrodes;
• an electric field is not generated in the second active portion under a condition that an electric field is generated in the first active portion, and an electric field is not generated in the first active portion under a condition that an electric field is generated in the second active portion.