An ink jet head for ejecting ink, has an ink ejecting portion having an ink ejecting port formed thereon so as to eject ink through the ink ejecting port, a positioning portion for definitely determining the position of the ink jet head relative to an apparatus using the ink jet head when the ink jet...http://www.google.de/patents/US6151051?utm_source=gb-gplus-sharePatent US6151051 - Detachable ink jet unit and ink jet apparatus
