LIQUID INJECTION HEAD, LIQUID INJECTION HEAD UNIT, LIQUID INJECTION DEVICE, MAINTENANCE METHOD FOR LIQUID INJECTION DEVICE, AND METHOD FOR INTRODUCING LIQUID

摘要

To provide a liquid injection head unit which can discharge air bubbles in a manifold to the outside and prevents foreign matters of ink from reaching a nozzle hole even when the foreign matters thereof are generated, and a liquid injection device.SOLUTION: A liquid injection head unit comprises: a drive part 20 for injecting liquid in pressure chambers 112 from nozzle openings 25 communicating with the pressure chambers 112; a common liquid chamber 100 communicating with a plurality of pressure chambers 112; an air bubbles return flow passage 80 communicating with the common liquid chamber 100 for discharging air bubbles in the common liquid chamber 100; and a control valve 400 provided in the air bubble return flow passage. The control valve 400 comprises a valve seat 412 and a valve body 402 being brought into contact with the valve seat 412 or separated therefrom, comprises a gap between the valve body 402 and a contact part of the valve seat 412, by separation between the valve seat 412 and the valve body 402, permits flow in one direction in which the air bubbles are discharges, and, on the other hand, permits the flow via the gap at the time of contact of the valve seat 412 with the valve body 402.SELECTED DRAWING: Figure 9