Patent ID: 7891795

Claim:
A printer comprising: an inkjet printhead having an ink inlet, an ink outlet and an array of nozzles; an ink chamber having an outlet port connected to said ink inlet via an upstream ink conduit; an air pump having a pump outlet communicating with a headspace in said ink chamber, said pump being configured to positively pressurize said headspace during a printhead priming operation; and a downstream ink conduit connected to said ink outlet, said downstream ink conduit communicating with a pump inlet of said pump, wherein said downstream ink conduit includes an expansion box for accommodating a volume of ink, thereby inhibiting said ink from reaching said pump inlet, and wherein said expansion box comprises: at least one expansion chamber, said expansion chamber having a respective chamber inlet defined in a base thereof, said chamber inlet being connected to said downstream ink conduit; a common air chamber having an air outlet defined in a base thereof, said air outlet being connected to said pump inlet via a pump inlet conduit; and a cover for said expansion chamber and said common air chamber, said cover defining a roof of said expansion box, said cover having at least one air channel defined therein, said air channel providing fluid communication between said at least one expansion chamber and said common air chamber.