| 摘要 |
PURPOSE:To remove bubbles in a printing head, by maintaining the pressure of the ink of the printing head at negative pressure by circulating ink in the sequence of an ink tank, and ink supply passage, the printing head and an ink discharge passage. CONSTITUTION:A pressure controller 6, under the printing instructions, makes a pressure pump 4, a suction pump 11 and magnet valve 5, 12 actuate and the ink at an ink tank 1 is circulated in the arrow direction. When printing, the hindrance of printing is prevented by rotating the ink 7 by continually controlling the inside of a printing head 2 by means of the controller 6 at a negative pressure. Even if bubbles 14 are generated or sent in the printing head 2, the bubbles 14 are delivered to the ink tank 1 through an ink discharge passage 10 with the ink 7 without staying in the head 2 because the ink 7 is incirculation, and discharged by exposure to atmospheric air of the tank 1. |
