| 摘要 |
<P>PROBLEM TO BE SOLVED: To solve the problem of discharging bubbles staying in a head tank while suppressing wasted consumption of liquid with a simple structure without requiring complicated controlling. <P>SOLUTION: A valve unit 300 is attached to the head tank 35. The valve unit 300 includes an air discharge control valve 310 having a communication path, a spring 350 for urging the air discharge control valve 310 in a direction of opening the same, a valve seat 321 and an open/close valve 320 that opens or closes a discharge liquid flow path in association with an operation of the air discharge control valve 310. When an air discharge pump 200 is not driven, the air discharge control valve 310 holds its valve opened state and the open/close valve 320 holds its valve close state. When the air discharge pump 200 is driven, the open/close valve 320 is opened. Even when air flows in a communication path 305 under a condition that the open/close valve 320 is opened, the air discharge control valve 310 is maintained in its valve open state. When liquid flows in the communication path 305, the air discharge control valve 310 comes in the valve close state and the open/close valve 320 comes in the valve open state. <P>COPYRIGHT: (C)2013,JPO&INPIT |
