A multi-chamber ink cartridge for an ink-jet printer, the ink cartridge including a printhead to eject ink droplets on a printing medium; a unitary body comprising: first, second and third ink chambers formed by “T”-shaped vertical walls in the unitary body, and first, second, and third ink channels respectively connected to a lower portion of each of the ink chambers to supply ink to the printhead; and a flexible printed circuit to apply an electrical signal to nozzles of the printhead; wherein the first chamber is disposed perpendicular to the second chamber and the third chamber, and the printhead is disposed on a lower portion of the unitary body which corresponds to the second and third chambers.