Patent ID: 8398217

Claim:
Drop-on-demand inkjet printing device comprising at least one through-flow print head, the through-flow print head having one or more nozzles for ejecting a drop of fluid onto a substrate to be printed, and a fluid circulation system for feeding and circulating fluid through the print head, said fluid circulation system comprising: a main reservoir for containing an amount of fluid, a supply buffer tank for receiving fluid from the main reservoir and supplying fluid to the through-flow print head, and a return manifold for receiving fluid from the through-flow print head and returning fluid to the main reservoir, wherein the main reservoir is connected to the supply buffer tank via a feed conduit provided with a pump means for directing fluid from the main reservoir to the supply buffer tank, wherein the supply buffer tank is in fluid communication with the one or more nozzles of the through-flow print head via a nozzle supply conduit, the one or more nozzles being in fluid communication with the return manifold via a nozzle return conduit, wherein the return manifold is connected to the main reservoir via a discharge conduit, wherein the main reservoir and the supply buffer tank are arranged in height with respect to the one or more nozzles such that during operation a back pressure is established at the one or more nozzles and fluid flows from the supply buffer tank through the through-flow print head to the return manifold and then back into the main reservoir, and wherein the supply buffer tank is provided with at least one further lockable conduit connecting the supply buffer tank to the main reservoir.