Patent ID: 6811241
Filing Date: 2004-11-02
Classification: B41J

Abstract:
A method of measuring a natural vibration period of a liquid jetting head provided with a nozzle orifice, a pressure chamber communicated with the nozzle orifice, a liquid supply port which supplies liquid into the pressure chamber, and a pressure generation element which causes pressure fluctuation in the liquid contained in the pressure chamber, the method comprising steps of:providing a first evaluation signal including a first excitation element adapted to excite pressure fluctuation in liquid contained in the pressure chamber and a first ejection element which follows the excitation element after a first time period to eject a first liquid droplet from the nozzle; providing a second evaluation signal including a second excitation element adapted to excite pressure fluctuation in liquid contained in the pressure chamber and a second ejection element which follows the excitation element after a second time period to eject a second liquid droplet from the nozzle, which is longer than the first time period; supplying the first evaluation signal to the pressure generating element to measure a first ejected amount of the first liquid droplet; supplying the second evaluation signal to the pressure generating element to measure a second ejected amount of the second liquid droplet; calculating an ejected amount ratio of the first ejected amount and the second ejected amount; and determining the natural vibration period of the liquid jetting head based on the ejected amount ratio.