An ink refill unit for replenishing an ink cartridge in an inkjet printer, the ink cartridge having an interface for engaging the ink refill, an ink storage compartment partially defined by a tubular flexible wall, and a constrictor mechanism for constricting the flexible tubular wall by a predetermined...http://www.google.de/patents/US7255430?utm_source=gb-gplus-sharePatent US7255430 - Ink refill unit with cartridge constriction actuators
