Abstract: A combined ink cartridge/bubble removing device is detachably secured to an ink liquid supply system for an ink jet system printer of the charge amplitude controlling type. The combined ink cartridge/bubble removing device includes a housing having a bottom wall provided with an ink inlet portion and an ink outlet portion. An ink liquid tray is disposed in the housing near the middle height of the housing. The ink liquid tray has an inlet opening which is connected to the ink inlet portion via a vertically disposed pipe, and an outlet small opening for dropping ink liquid within the housing. Ink liquid collected by a beam gutter is introduced into the combined ink cartridge/bubble removing device through the ink inlet portion. While the ink liquid travels upward in the vertically disposed pipe, bubbles included in the ink liquid are removed, and the bubbles are discharged from the free surface of the ink liquid held on the ink liquid tray.