A pressure-regulating chamber for maintaining ink contained in the chamber at a predetermined first level relative to a printhead. The chamber comprises: an inlet port for connection to an ink reservoir via an ink supply line; an outlet port for connection to an ink inlet of the printhead via an upstream ink line; a return port for connection to an ink outlet of the printhead via a downstream ink line; a snorkel extending from the return port and terminating at a snorkel outlet positioned above the first level of ink; an air vent open to atmosphere; and a float valve for maintaining the predetermined first level of ink by controlling a flow of ink into the inlet port.