Patent ID: 8733908

Claim:
A printing system comprising: an elongate printhead having first and second ink ports; an ink containers fluidically interconnected with the printhead via a respective closed fluid flow loop, the ink container having an outlet port and a return port; a first ink line interconnecting the outlet port and the first ink port of the printhead; a second ink line interconnecting the return port and the second ink port of the printhead; a pump positioned in the second ink line for pumping fluid around the closed fluid flow loop; a first valve arrangement positioned in the first ink line for selectively allowing ink flow between the outlet port and the first ink port of the printhead by selectively moving a pinch element into and out of pinching contact with the first ink line so as to block and allow ink flow therethrough; a vent line having one end open to atmosphere and an opposite end fluidically, connected to the first ink line, the vent line being connected to the first ink line between the first valve arrangement and the first ink port of the printhead; and a second valve arrangement for opening and closing the vent line.