Abstract: A three-color ink-jet cartridge has a conduit connecting an ink reservoir to a print head orifice. The conduit has a pair of internal longitudinal grooves to permit ink to flow past a trapped bubble in the conduit. This ink flow prevents ink leakage through the orifice when ambient pressure changes cause the trapped bubble to expand.

Abstract: An ink-jet pen is disclosed that has a body of resilient felted polyurethane foam mounted in an ink chamber for ink retention and backpressure. A rectangular ink pipe extends from a bottom wall of the ink chamber between the walls of the ink chamber. A wire mesh filter is mounted to the ink pipe. The ink pipe and mesh filter extend into compressive contact with the foam to locally increase the capillarity of the foam. Any air that comes out of solution collects as a bubble in the rectangular ink pipe. This bubble does not block ink flow to the printhead, however, because the corners of the rectangular ink pipe provide a fluid capillary path. The bubble tends to form in a spheroid shape and does not extend into the corners of the ink pipe. In addition, rectangular filters are used, which reduces waste and expense compared to circular filters.

Abstract: A three-color ink-jet cartridge has a conduit connecting an ink reservoir to a print head orifice. The conduit includes a standpipe which has a pair of internal longitudinal grooves to permit ink to flow past a trapped bubble in the standpipe thereby preventing ink leakage through the orifices when pressure changes cause the trapped bubble to expand. The conduit also includes a tube from the standpipe to the print head. Disposed longitudinally along the tube is a rib which enables capillary flow of ink around a bubble in the tube to prevent depriming of the print head.