Filter device for ink jet printer

摘要

A filter device that is usable for a print head in an ink jet printer. The filter device is interposed between an ink reservoir and the ink ejecting nozzles. Two flat, permeable thin films are juxtaposed with an adequate clearance from the inlet of a filter chamber toward the outlet thereof to define negative pressure chambers. A flat filter member is interposed in parallel with an adequate clearance H between the two permeable thin films. Dust contained in ink is caught by the filter member. A negative pressure generator is used to decrease the pressure inside the negative pressure chamber to less than that of atmospheric pressure so as to remove bubbles contained in the ink in the filter chamber. Consequently, it is possible to prevent dust and bubbles from intruding into the ink ejecting nozzles in the ink jet printer to ensure there is no interruption of the ejection of the ink.