Patent ID: 7794038

Claim:
An ink pressure regulator for regulating a hydrostatic pressure of ink supplied to an inkjet printhead, said regulator comprising: an ink chamber having an ink outlet for fluid communication with the printhead via an ink line; an air inlet; a regulator channel having a first end communicating with the air inlet and a second end defining a bubble outlet, said bubble outlet being positioned for bubbling air bubbles into a headspace of the chamber at all operative ink levels; and a wetting system for maintaining at least some liquid in said regulator channel at all operative ink levels, thereby ensuring that air entering the headspace first passes through said liquid; wherein said regulator channel is dimensioned to control a Laplace pressure of air bubbles drawn from said bubble outlet as result of supplying ink to the printhead, thereby regulating a hydrostatic pressure of the ink; and wherein said wetting system is fluidically isolated from a reservoir of ink in said ink chamber.