Inkjet print cartridge having a first inlet port for initial filling and

Abstract

An inkjet print cartridge is described which allows recharging of the ink supply in the print cartridge without removing the print cartridge from the printer. In a preferred embodiment, the ink reservoir in the print cartridge consists of a spring-loaded collapsible ink bag, where the spring urges the sides of the ink bag apart and thus maintains a negative pressure within the ink bag relative to ambient pressure. The ink bag is initially filled through a first fill port in the print cartridge. The first fill port is then sealed with a stopper. The print cartridge is installed in a slideable carriage in an inkjet printer. As the ink is depleted during use of the print cartridge, the ink bag progressively collapses and overcomes the spring force. A slideable, generally cylindrical ink valve extends through the print cartridge body and into the ink bag. The valve is open when pushed into the print cartridge body and closed when pulled away from the print cartridge body. An ink refill system containing a supply of ink is connected to the valve on the print cartridge by a flexible tube. The negative pressure within the print cartridge ink bag draws the ink from the ink refill system reservoir into the ink bag continuously or at intermittent times.