| 摘要 |
PROBLEM TO BE SOLVED: To provide an inkjet image-forming apparatus which enables a fixed negative pressure to be applied to a printing head regardless of the position of the printing head. SOLUTION: A printing system 10 is equipped with a pressure adjusting unit 50 equipped with a suction/discharge pump 52 for applying a proper negative pressure to the printing head 32K and performing a cleaning operation and an ink tank unit 40 for storing an ink consumed for printing. The pressure adjusting unit 50 is composed of a sub-tank 58 equipped with a recovery valve 56 for opening and closing a passage 54 communicated with an atmospheric air, a liquid level detection sensor 60 for detecting the level position of the ink stored in the sub-tank 58 and the suction/discharge pump 52 which has a discharge function for discharging the ink from the sub-tank 58 and a feed function for feeding the ink to the sub-tank 58. The suction/discharge pump 52 has a function for keeping the pressure of the ink in the printing head 32K at a predetermined negative pressure. COPYRIGHT: (C)2007,JPO&INPIT |
