| 摘要 |
PURPOSE:To detect the presence of air bubbles and the state of filling-up of ink in an ink chamber, by detecting the repetition cycle of a vibration waveform in a driving circuit of a piezoelectric element and in a vibration waveform shaping circuit at the time of driving, and by detecting therefrom the presence of the air bubbles in the ink chamber. CONSTITUTION:When a piezoelectric element driving waveform deformation Vo deformation of a piezoelectric element 9 is observed, it is seen that the piezoelectric element driving waveform Vo vibrates with a certain cycle after the piezoelectric element 9 is distorted. In the case when there are air bubbles in an ink chamber 23 or when ink is not filled up therein at all, a vibration waveform observed in this case is different from the one in a normal case since the impedance of the piezoelectric element changes, and therefore it can be distinguished from the latter. Based in that there is a large distinction between the frequency of this vibration waveform in the normal case and that in an abnormal case, it can be detected that air bubbles are present in the ink chamber 23 and that the ink is not filled up therein, by detecting the cycle of the vibration waveform. |
