A refillable ink cartridge has an ink port for both supplying ink to a printhead and refilling the cartridge. An ink reservoir has ink absorbent material disposed therein with a main fluid channel extending between the ink port and the ink absorbent material. A bypass fluid channel with a control valve extends between the main fluid channel the said absorbent material. The bypass control valve is configured to allow ink to flow through the bypass fluid channel only when refilling the ink reservoir via the ink port.