| 摘要 |
PURPOSE:To obtain the printer in the title wherein abnormal pressure in a liquid chamber is detected through a piezoelectric vibrator, a solenoid controlled valve provided in an ink supplying path is cut off at the time of abnormality, and occurrence of poor printing and the damage of the device can be prevented in advance. CONSTITUTION:The electric field which is proportional to the bending vibration of the piezoelectric vibrator 6 is generated at the part of an auxiliary detecting electrode 9 which occupies a part of one surface of the piezoelectric vibrator 6. An AC voltage is outputted from the part between the auxiliary electrode 9 and a grounding electrode 7. Said output passes through a signal smplifier 11, a rectifier 12, and an integrating circuit 13 and is compared with a reference voltage in a comparator 15. When the detected voltage is too large, the control signal is outputted, a driving circuit 16 is operated, and the solenoid controlled valve 3 is closed. |
