Abstract: Provided is a valve assembly for a printer ink cartridge. The valve assembly includes a flanged valve stem defining an inlet opening with a skirt engaging portion for operatively engaging an outlet port of the cartridge, and a depressible valve member within the stem. The valve assembly also includes a pressure regulator having a spacer within a central hub and a diaphragm spanning a central inlet opening. The pressure regulator further includes a clip defining an outlet opening, the clip configured to operatively engage the valve stem to sandwich the valve member, spacer and diaphragm between the valve stem and clip. The pressure regulator also includes a spring configured to bias the diaphragm against the central inlet opening into a closed position, so that ink from the ink cartridge is only able to flow through the valve when the diaphragm is in an open position.