Abstract: A method for refilling an inkjet cartridge such that there is little or no ink leakage. Turning the cartridge upside-down, the ink reservoir vent, on the base of the cartridge, is held facing up, allows air to vent, while the ink is dispensed into the cartridge at the opposing end of the reservoir. The components used to perform the refill operation are tapered fittings that securely lock together and make a tight seal on the fill port of the cartridge so that ink will not spill out during the filling operation. Once the cartridge has been refilled, a negative pressure reservoir is provided to create and maintain a negative pressure, or vacuum, required to keep the printer cartridge operational until it exhausts its supply of ink. The negative pressure reservoir (n.p.r.) is connected to the fill port of the cartridge, with out the need to displace or remove any ink from the cartridge. The n.p.r. is removable in order to repeat the refill procedure as many times as allowed by the performance of the printhead.