US Patent 7794063 Liquid-droplet jetting head and liquid-droplet jetting apparatus

An ink-jet head includes a channel unit which includes a plurality of pressure chambers, a vibration plate stacked on the channel unit, and a piezoelectric material layer arranged on the vibration plate. The piezoelectric material layer includes a first portion functioning as a piezoelectric actuator, and a second portion functioning as a piezoelectric transformer which amplifies a driving signal to be supplied to the piezoelectric actuator. Accordingly, it is possible to realize a small-size ink-jet head with a built-in piezoelectric amplifier.