| 摘要 |
PURPOSE:To enable to obtain a predetermined jetting velocity for a droplet with a lower driving voltage by positively utilizing the damped vibration of a vibration system which consists of the walls of a pressure chamber, an electromechanical transducing means and an ink. CONSTITUTION:A piezoelectric element 9 expands in radial directions to lift up the wall 5 when charging is started. At this time, the ink 6 is sucked in through a supply port 4, while air is sucked in through an opening 3a. When the charge accumulated in the piezoelectric element 9 is instantaneously discharged around the time the sucked-in amount 20 of air reaches a maximum, the wall 5 and the element 9 are returned to their original positions due to the elastic energy accumulated in them, so that the ink 6 sucked into the pressure chamber 2 is discharged into the air as the droplet 21. The wall 5 and the piezoelectric element 9 performs damped vibrations after the charging is started, the timing of the maximum of the damped vibration being substantially coincident with the timing of the maximum sucking-in of air. |
