An ink supply system includes an ink cartridge and a cartridge mounting portion. The ink cartridge includes an ink chamber, and a tube having a first opening and a second opening formed therein. The first opening extends from a first end of the tube, and the second opening extends from a second end of the tube opposite the first end of the tube. The first opening is configured to be in fluid communication with the ink chamber via the first end of the tube, and the second opening is configured to be in fluid communication with an exterior of the tube via the second opening of the tube. The cartridge mounting portion includes a projection configured to be inserted into the second opening of the tube via the second end of the tube. A diameter of the second opening is less than an outer diameter of the projection.