Patent ID: 6364471
Filing Date: 2002-04-02
Classification: B41J

Abstract:
A printing system, comprising:a) a print cartridge including an ink jet print head, an ink receptacle in fluid communication with said print head, and an ink input port in fluid communication with said ink receptacle, said ink receptacle containing ink at a first pressure; b) an ink container external to said print cartridge, said ink container containing ink at a second pressure, where said second pressure is greater than said first pressure; c) a conduit for transporting ink from said ink container to said print cartridge; and d) a pressure regulator disposed in said ink receptacle, coupled to said ink input port and in communication with an atmospheric air pressure, said pressure regulator receiving ink via said ink input port at said second pressure from said ink container, supplying ink at said first pressure to said print head, and accommodating a pressure difference between said first pressure and said atmospheric pressure, said pressure regulator opening said ink input port when said first pressure in said ink receptacle is sufficiently less than said atmospheric air pressure and changing a volume of said ink receptacle without opening said ink input port when said first pressure changes relative to said atmospheric air pressure due to changes in print cartridge temperature; wherein said ink input port comprises an ink orifice disposed within said print cartridge and wherein said pressure regulator comprises a lever including an arm rotating about an axle and a valve seat disposed on said arm opposite said ink orifice such that said ink orifice is blocked by said valve seat when said arm is in a first position and not blocked by said valve seat when said arm is in a second position corresponding to an opening of said ink input port; wherein said pressure regulator comprises a spring coupled to said arm and an expandable and contractible member coupled to said atmospheric air pressure and coupled to said arm in opposition to said spring, to detect when said first pressure is less than said atmospheric air pressure, wherein said arm is rotated about said axle to unblock said ink orifice when said first pressure is sufficiently less than said atmospheric air pressure.