Patent ID: 8231212

Claim:
An ink delivery system comprising: a first tank including a fill sensor; a second tank, wherein the first tank is in fluid communication with the second tank; a first pump configured to pump ink supplied from the first tank to the second tank; a third tank; a second pump configured to pump ink directly from the second tank to the third tank; a drop-on-demand flow-through print head in direct fluid communication by conduit or passageway with each of the second tank and the third tank, wherein the third tank is in fluid communication with the first tank, the second tank is in fluid communication with the third tank, negative pressure is provided in the third tank, ink can be controllably jetted from the print head and a pressure differential across the print head causes unjetted ink to flow through the flow-through print head and directly into one of the second tank or third tank by conduit or passageway.