Patent ID: 7658466

Claim:
An ink priming system for a cartridge unit of the type having a pagewidth printhead assembly in fluid communication with one or more ink storage compartments, the system comprising: a priming inlet provided on said pagewidth printhead assembly for receiving an external supply of ink; an ink flow passage providing fluid connection between said pagewidth printhead assembly and each of the ink storage compartments; an ink retaining member located within each ink storage compartment for receiving and storing ink; and a vent hole defined through a surface of each ink storage compartment, the vent hole being defined through a surface opposite an entry point of the ink flow passage into the ink storage compartment, whereby the ink retaining member is interposed between the vent hole and the entry point, wherein ink is supplied to the priming inlet of the pagewidth printhead assembly to flow from the pagewidth printhead assembly to the ink storage compartment via the ink flow passage, ink is drawn into the ink retaining member with assistance from a capillary force facilitated by the vent hole, and the ink received via the ink flow passage primes both the printhead assembly and the ink retaining member of each ink storage compartment with ink substantially simultaneously.