Patent ID: 7147390

Claim:
A system for supplying processing solution to a printing device comprising: a. a supply tank adapted to hold the processing solution; b. a printing device adapted to print images; c. a delivery system in fluid communication between the supply tank and the printing device, wherein the delivery system comprises i. a retaining vessel adapted to hold a retained fluid; ii. an adjustable liquid level probe set at a first specific depth in the retaining vessel and adapted to sense a predetermined amount of the retained fluid in the retaining vessel; and iii. a reference probe set at a second specific depth and adapted to provide a reference probe signal to the adjustable liquid level probe; d. a power supply adapted to receive the adjustable liquid level probe signal from the adjustable liquid level probe; and e. a thee-way valve adapted to flow the sensed predetermined volume of the retained fluid from the retaining vessel to the printing device and from the supply tank to the retaining vessel when actuated by the power supply.