Patent ID: 7334880

Claim:
A driving method for a droplet jetting head comprising a nozzle orifice to jet a droplet, a pressure generating chamber communicating with the nozzle orifice, the pressure generating chamber can store liquid, and a pressuring device to enlarge or shrink a volume of the pressure generating chamber, the driving method comprising the steps of: a first step for increasing the volume of the pressure generating chamber by the pressuring device; a second step for decreasing the volume of the pressure generating chamber by the pressuring device to protrude liquid in the pressure generating chamber from the nozzle orifice after the first step; and a third step for increasing the volume of the pressure generating chamber by the pressuring device, and separating liquid protruded from the nozzle orifice by the second step as a droplet, when α/β is equal to or less than ⅓ where β(μm) is a diameter of a liquid pillar protruded from the nozzle orifice by the second step at a front end of the nozzle orifice and β(μm) is a maximum diameter of the liquid pillar; wherein a time period during which the second step lasts is 3.5-4.4 AL, where AL is one half of an acoustic resonant period of the pressure generating chamber.