Patent attributes
An inkjet printer that has a replaceable ink cartridge with an ink storage volume and an ink outlet. The ink outlet has an outlet valve that is biased closed and opens upon installation in the printer. The cartridge also has an air bag in the ink storage volume for expanding as ink is drawn through the ink outlet to keep a constant head of ink above the outlet valve. The air bag has an air inlet with a frangible seal configured to be ruptured upon installation of the cartridge such that the air bag is vented to atmosphere. The printer also has a pressure regulating valve for establishing fluid communication between the printhead and the ink storage volume wherein, the pressure regulating valve is biased closed and opens in response to a predetermined ink pressure difference across the valve.
