An ink jet printer apparatus is adapted to secure a print cartridge which includes an open container having a top opening; a porous ink-absorbent in the container; a print head in ink communication with the porous ink-absorbent; a top cover lid adapted to be placed on the container, over the top opening, to close the container; and an ink conduit needle mounted on the top cover lid to longitudinally extend in a horizontal orientation above the porous ink-absorbent when the cover lid is placed on the container, so that a print ink can descend freely by the force of gravity from the ink conduit needle onto the porous ink-absorbent and from the porous ink-absorbent down to the print head. The ink jet printer apparatus has a resilient septum; an ink delivery connection to the septum; a stall for receiving the print cartridge in a substantially horizontal direction, so that the ink conduit needle mounted on the top cover lid is horizontally inserted through the septum; and a cover door movable closed to cover the print cartridge when the print cartridge is received in the stall, and adapted to secure the print cartridge in place within the stall to ensure that the ink conduit needle cannot be dislodged from the septum.