LIQUID SUPPLY SYSTEM, LIQUID CONTAINER, HEAD CARTRIDGE, INK JET CARTRIDGE, LIQUID SUPPLY CONTAINER, METHOD FOR COUPLING THE HEAD CARTRIDGE WITH THE LIQUID SUPPLY CONTAINER, COMMUNICATION UNIT USED FOR THE LIQUID SUPPLY SYSTEM, INK JET RECORDING APPARATUS PROVIDED WITH THE INK JET CARTRIDGE OPENING/CLOSING VALVE USED FOR THE LIQUID CONTAINER, AND LIQUID SUPPLY CONTAINER PROVIDED WITH THE OPENING/CLOSING VALVE