Hydraulically tuned channel architecture

An improved ink-jet printhead including a plurality of ink-propelling elements (12), each ink-propelling element disposed in a separate firing chamber (26) defined by three barrier walls (36) and a fourth side open to a reservoir of ink common to at least some of said elements, and a plurality of nozzles (16) comprising orifices disposed in a cover plate above said elements, each orifice associated with an element for firing a quantity of ink (A) normal to the plane defined by each said element and through said orifices toward a print medium in defined patterns to form alphanumeric characters and graphics thereon, wherein ink is supplied to said element from a plenum chamber (14) by means of an ink feed channel (10), wherein the improvement comprises:

• (a) a pair of opposed projections (28) formed in walls in said ink feed channel and separated by a first width (W.sub.1) to cause a first constriction between said plenum and said channel;
• (b) a second constriction (30) along the length of said ink feed channel defined by a second width (W.sub.2) between said walls of said ink feed channel, said second width narrow than the width of said firing chamber and wider than said first width between said opposed projections and sufficient to physically support said projections without adversely adding to resistance to ink refill of said channel;
• and
• (c) means (38) for assisting in purging any bubbles in said ink, said means comprising a pair of lead-in lobes disposed between said projections and said plenum chamber and separating one ink feed channel from a neighboring ink feed channel.