An ink cartridge, which is removably set in a printer, has an ink chamber storing ink, an absorbent chamber containing a sponge that absorbs the ink from the ink chamber and holds it, and a fuel chamber storing a liquid fuel to be supplied to a fuel cell of the printer. The fuel chamber is located outside and adjacent to the ink chamber, so that the ink stored in the ink chamber is kept in a constant temperature range. Data on residual amounts of the ink and the fuel in the ink cartridge are detected by a residual ink detector and a residual fuel detector of the printer, and are written in a memory card that is removably attached to the ink cartridge.