This disclosure provides a valve which is controlled by a magnetic actuator. More specifically, the actuator is a polarized, magnetic actuator, that is, a magnetic actuator containing both a permanent magnet and an electromagnet. The actuator can be an inexpensive commercial relay having a pivoting armature that pushes a compliant diaphragm against a valve seat to close the valve. Preferably, the armature is configured as a “see-saw,” such that as the valve is opened, an opposing end of the see-saw also displaces the diaphragm. In this manner, fluid pressure in a valve chamber is relatively constant, and there are no significant pressures which prevent the valve from opening and closing. The preferred application of the valve is to actively drive printer ink supply, such that ink can be selectively drawn using the valve from a remote ink supply into a local ink reservoir, mounted near a print head. A sensor at the local reservoir is used to detect air or low pressure, and causes the valve to open and draw more ink into the local reservoir.