Patent ID: 7527353

Claim:
An ink cartridge for a printer with an inkjet printhead, the ink cartridge comprising: a rigid housing, the housing having a docking face for abutting the printer such that when installed, the docking face faces downwards; an ink storage volume; an ink outlet valve for fluid communication with the printhead, the ink outlet valve and an air inlet both being positioned in the docking face; a variable volume structure within the ink storage volume, the variable volume structure being inflatable with air and having a section upwardly displaceable within the ink storage volume as air inflates the variable volume structure during use; and, the air inlet spaced from the outlet valve and in fluid communication with the variable volume structure such that the air inlet lets air into the ink storage volume as ink is drawn out through the outlet valve, the air inlet having a frangible seal to provide an air tight seal prior to installation of the ink cartridge; wherein, the outlet valve and the air inlet are configured for engagement with complementary formations on the printer such that the ink outlet valve is opened upon installation of the cartridge in the printer, and the frangible seal is ruptured upon installation in the printer.