An ink containing device includes an ink cartridge and an adaptor. The ink cartridge comprises a first main body comprising a chamber configured to store ink, and an ink outlet portion disposed on a first surface of the first main body configured to direct the ink from the chamber to an exterior of the first main body, and an ink detecting portion configured to detect an amount of the ink stored in the ink chamber. The adaptor is configured to attach to the ink cartridge. The adaptor comprises a second main body comprising a second surface, and an electrical interface disposed on the second surface.