Liquid jetting apparatus and method for driving the same

A method of driving a liquid jetting apparatus which comprises a jetting head, provided with a nozzle orifice, a pressure chamber communicated with the nozzle orifice, and a piezoelectric element which is deformable to cause pressure fluctuation to liquid contained in the pressure chamber, the method comprising the steps of:

• generating simultaneously a plurality of drive signals, each provided with waveform elements including at least one drive pulse in every unit jetting cycle, the drive pulse deforming the piezoelectric element to cause such pressure fluctuation as to eject a liquid droplet from the nozzle orifice;
• providing a switcher which selectively supplies at least one of the waveform elements included in one of the drive signals to the piezoelectric element;
• and
• controlling a selective supply operation of the switcher in accordance with amount data which indicates an amount of the liquid droplet to be ejected,
• wherein a time period in which the drive pulse is generated in one of the drive signal and that in another one of the drive signals overlap at least partly.