| 摘要 |
PURPOSE:To reduce the size of ink droplets jetted and enable clear recording in a high density, by applying a driving waveform with a period of an integer times a period 1/(2fR2), wherein fR2 is the frequency of vibration of the normal mode of an ink jet head, to a piezoelectric element of the ink jet head. CONSTITUTION:When an ink jet head is loaded with an ink and the frequency of a sinusoidal driving waveform applied to a piezoelectric element is gradually raised, the displacement quantity of a nozzle meniscus has peaks at frequencies fR1 and fR2, which are the frequencies of vibration of the normal modes of the ink jet head. When a driving waveform with a period of 1/(2fR2) (namely, n=2) is applied to the piezoelectric element of the ink jet head, the liquid surface of an ink is brought into vibration corresponding to a resonant state of a high order mode. In this experiment, the inside diameter of the nozzle is 50mum and the diameter of an ink droplet jetted is about 20mum. Accordingly, the ink droplet is reduced to about 1/3 in diameter and to about 1/27 in volume, as compared with an ink droplet obtained by a conventional system. |
