| 摘要 |
PURPOSE:To detect remaining quantity of ink without fail by providing a flexible piezoelectric sheet which is fixed on an end face of the sidewall of an ink passing chamber and blocks an opening so as to detect the remaining quantity of the ink by an output voltage of the flexible piezoelectric sheet. CONSTITUTION:During the time where there is enough ink in an ink bag 5, the pressure of the ink in a flow passage is almost constant, a first ink passing chamber 2a is also filled with ink, and a flexible piezoelectric sheet 11 bends to the outside in an expanding way. A voltage is generated by the deflection. The voltage is detected through leads 12a and 12b and the presence of enough ink can be detected. When the ink in the ink bag 5 runs out, the ink in the first ink passing chamber 2a also decreases, the flexible piezoelectric sheet does not bend, and the voltage is not generated. When the ink decreases further, a negative pressure generates in the first ink passing chamber 2a and the flexible piezoelectric sheet 11 bends to the inside. At this time, a voltage with a pole reverse to the time when it is bent to the outside is generated. A running out of the ink can be detected by detecting this voltage. |
