Techniques for liquid replenishment in a printer/plotter. An ink delivery system (IDS) is employed wherein the on-carriage spring reservoir of the print cartridge is manually and securely connected to the off-carriage reservoir. A pen cartridge that uses an internal spring to provide vacuum pressure is connected from an inlet port through a unitary coupler to an ink reservoir located off the scanning carriage axis. The coupler serves to align as well as to secure two mating valves to securely hold them together in an open latched position which is not intended to be modified or disconnected until the entire ink supply has been depleted. A replaceable ink supply module for providing replenishment of an inkjet printhead includes a collapsible bag, an enclosure box, a connective tube, and an on/off valve. These four components are incorporated into a composite sealed system which remains intact during shipment, storage, installation and operation. The collapsible bag is placed inside the protective enclosure box and has an end-connect outlet permanently attached to one end of the connective tube. The other end of the connective tube carries a permanently attached on/off valve designed for engagement with an inlet valve of an inkjet printhead.