An improved inkjet printer ink cartridge is provided having a print head unit and a housing. The print head unit has a head chip in which a nozzle hole is formed to fire ink onto paper, and a flexible circuit board for transceiving signals with a printer system. The housing has a receiving part at the bottom thereof to receive the print head unit, and an ink chamber disposed therein, the receiving part having an ink feed hole including a dam on its circumference, and a secondary dam of the same height as the dam. Accordingly, when attaching the print head unit into the housing print head receiving part, the print head unit is prevented from being slanted. Further, problems from heat stress when an adhesive is heat cured, such as a membrane crack, or a circuit wire or conductive path breaking, are minimized.