Patent ID: 8348406

Claim:
A liquid ink delivery system comprising: an inkjet printing apparatus having an ink reservoir and a plurality of inkjet ejectors, the inkjet printing apparatus being configured to purge ink from the ink reservoir through the inkjet ejectors; an ink receptacle having an inlet positioned proximate the inkjet printing apparatus to receive ink purged through the plurality of inkjet ejectors; a second ink reservoir having an outlet; a first conduit having a first end and a second end, the first end of the first conduit being fluidly connected to the ink receptacle; a second conduit having a first and a second end, the first end of the second conduit being fluidly connected to the ink reservoir of the inkjet printing apparatus; a bi-directional pump operatively connected to the second end of the first conduit, the second end of the second conduit, and the outlet of the second ink reservoir; a first one-way valve fluidly connected between the pump and the first end of the first conduit; a second one-way valve fluidly connected between the pump and the first end of the second conduit, the first and the second one-way valves enabling the pump to move purged ink from within the ink receptacle through the first conduit to the outlet of the second ink reservoir in response to the pump operating in a first direction and to move ink from the second ink reservoir through the outlet and the second conduit to the ink reservoir in the inkjet printing apparatus in response to the pump operating in a second direction; a porous member positioned within the ink receptacle between the inlet and the first one-way valve, the porous member being configured to enable ink to pass through the porous member at a first negative pressure and to enable air to pass through the porous member at a second negative pressure that is greater in magnitude than the first negative pressure; and a flow restrictor having a first end and a second end, the first end of the flow restrictor being operatively connected between the first one-way valve and the pump and the second end of the flow restrictor being operatively connected between the pump and the second ink reservoir, the flow restrictor being configured to enable ink to flow from the second ink reservoir to a position between the first one-way valve and the pump through a second fluid flow path to establish a negative pressure at the porous member that is between the first pressure and the second pressure to prevent the pump from moving air through the porous member in response to the pump operating in the first direction.