An ink cartridge may have an ink accommodating portion shaped to contain ink, an ink supply hole disposed at a bottom of the ink accommodating portion, and a valve unit including a movable valve portion and a fixed valve portion, the movable valve portion being oriented such that a flow of ink is regulated...http://www.google.fr/patents/US6666551?utm_source=gb-gplus-shareBrevet US6666551 - Ink cartridge
