Replaceable ink cartridge

A replaceable ink cartridge for a bubble jet printer having a carriage adapted to scan a recording sheet, an ink jet print head having an ink port for supplying liquid ink thereto and being mounted to the carriage for ejecting liquid ink onto the recording sheet by the action of thermal energy while the carriage scans the recording sheet, and a mounting on the carriage for receiving said replaceable ink cartridge and supporting same for connection to the ink port of the ink jet print head, said replaceable ink cartridge comprising:

• a container formed by a front wall, back wall, top wall and bottom wall, each of which is elongated, and two side walls providing major surfaces of said container;
• a partition attached to said side walls and extending from said top wall toward said bottom wall to divide said container into a first chamber and a second chamber communicating with each other through an opening formed by said partition proximate to said bottom wall;
• said first chamber being defined by said partition and said back wall, top wall, bottom wall and said two side walls of said container and being generally sealed from ambient air except through said opening;
• said second chamber being defined by said partition and said front wall, top wall, bottom wall and said two side walls of said container and having an air vent for admitting ambient air into said second chamber;
• said first chamber containing a reservoir of liquid ink;
• said second chamber having an ink supply outlet in said front wall proximate to said bottom wall for supplying liquid ink to the ink port of the ink jet print head and containing a sponge-like material for producing a negative pressure whereby liquid ink is deliverable from said first chamber through said opening to said ink supply outlet;
• at least one groove in said partition extending from said opening to a position spaced from said top wall for forming an air flow passage from said second chamber to said first chamber through said opening, thereby permitting introduction of air into said first chamber and flow of liquid ink to said ink supply outlet through said opening;
• and
• said container being removably mountable in the bubble jet printer mounting with said bottom wall facing downward and said front wall facing the ink jet print head so that said ink supply outlet is connectable to the ink port of the ink jet print head.