Patent ID: 7806519

Claim:
A refill unit for a printer cartridge having an operatively, negatively pressurized ink reservoir, the refill unit comprising: a docking assembly for docking with the printer cartridge; an ink bag housed within a docking assembly for docking with the printer cartridge; a valve actuator shaped and configured to actuate an outlet valve of the ink reservoir into a closed position and thereafter to actuate an inlet valve of the ink reservoir into an open position when the docking assembly docks with the cartridge; constrictor actuators engageable with the cartridge and configured to increase pressure in the ink bag during ink flow from the ink bag to the ink reservoir, and to permit a re-establishment of negative pressure in the ink reservoir upon disengagement of the refill unit from the cartridge; and an integrated circuit with a plurality of projecting contacts readable by an integrated circuit reader of the cartridge when the docking assembly is engaged therewith to facilitate verification of suitability of the ink in the ink bag.