Ink jet printhead cleaning by means of a preservation fluid from a buffer tank

摘要

A head unit is inverted so that an outflow port is in the lowest position. Because the top wall of the buffer tank slopes downwards towards the outflow port, all remaining cleaning fluid that was introduced during manufacture is removed. Also, a notch is provided in the bottom end of an ink introduction port. The notch faces towards the outflow port so that bubbles in the ink exit from the notch and are guided towards the outflow port. The head unit is shipped while the buffer tank is filled with preservation fluid that has high wettability and any openings to the outside air are closed off with covers. When the head unit is used, the preservation fluid is sucked by a purging device and then ink, which has a high affinity for the preservation fluid, is smoothly introduced. Also, the inner surface of the filters are treated to increase the wettability by ink after the filters are fixed to the bottom lid. Afterwards the bottom lid is fixed to the top lid to form the buffer tank.