Patent ID: 7497562

Claim:
A re-circulating fluid delivery system, comprising: a fluid structure; a housing structure; an air-fluid separator structure disposed in said housing structure, the separator structure including an air vent; a fluid plenum in fluid communication with said separator structure; a free fluid reservoir disposed in said housing structure; a fluid interconnect structure for removable connection of the fluid supply to the free fluid reservoir; a fluid re-circulation path within said housing structure fluidically coupling said separator structure, said fluid plenum and said free fluid reservoir; and a pump structure for re-circulating fluid through said re-circulation path during a pump mode, wherein air bubbles may be separated from re-circulated fluid and vented to atmosphere from said air vent region; a fluid supply and a fluid interconnect structure for removable connection of the fluid supply to the free fluid reservoir; and wherein said fluid supply and said free fluid reservoir are continuously connected during printing operations performed by the print cartridge and during refill operations wherein replenishment fluid is transferred from the fluid supply to said free fluid chamber through the fluid interconnect.