A protection device for an ink cartridge storage unit having an ink inducing member is provided with a supporting beam, a funnel member having a narrow conical end and a wide conical end, the narrow conical end being connected to a distal end of the supporting beam, and an elastic cap arranged inside the funnel member. The elastic cap seals the ink inducing member in an engaged state. In the course of removing the protection device from the ink cartridge storage unit, the protection device can be lifted in the upper direction. The upper rim of the wide conical end makes contact with the rear surface of the ink cartridge storage unit in due course. As the protection device is lifted further, the part of the elastic cap is constricted, and the upper rim of the wide conical end functions as the fulcrum for the leverage.