Patent ID: 7481521

Claim:
An air removal device for ink supply mechanism comprises: an ink chamber that is provided in an ink passage from an ink supply source to a recording head; an air discharge passage that is provided to discharge, out of the ink chamber, air flowing into the ink chamber with ink and collected therein; an air permeable membrane that is provided at an entrance or inside of the air discharge passage to pass air but not ink; a pump that applies a positive pressure to the ink chamber side or a negative pressure to the air discharge passage side in order to discharge air via the air discharge passage; and a movable member having an internal cavity functioning as a part of the air discharge passage and being displaced between a first position and a second position, the first position being chosen except when air is discharged via the air discharge passage and the second position being chosen when air is discharged via the air discharge passage, wherein when the movable member is displaced to the second position to operate the pump, air is discharged from the ink chamber to the air discharge passage, and the ink inside the ink chamber is brought into contact with the air permeable membrane while air is still left in a portion of space inside the ink chamber, and when the pump is then stopped and the movable member is displaced to the first position, one or both of air left in the portion of space and air present downstream in an air discharge direction of the air permeable membrane flows in between the air permeable membrane and the ink inside the ink chamber, so that the ink inside the ink chamber is separated from the air permeable membrane.