Abstract: An ink circulation system for use in an inkjet printing apparatus includes an inkjet printhead, an ink supply path for supplying an ink to the inkjet printhead and an ink return path for returning ink not used for printing from the inkjet printhead. The ink return path is coupled to the ink supply path for replenishing the ink supply path with the ink returned from the printhead. The coupling establishes an ink circulation circuit. The ink circulation circuit can be replenished with fresh ink from a main tank, as ink is withdrawn by the printhead for printing. In the circulation system an active through-flow ink degassing unit is provided to control the dissolved gas level of the ink in the ink circulation system.

Abstract: An ink circulation system for use in an inkjet printing apparatus includes an inkjet printhead, a supply subtank for containing a supply of ink for the inkjet printhead and a return subtank for containing a surplus of ink not used by the inkjet printhead. The supply subtank is coupled with the return subtank and with the inkjet printhead via a first fluid path. A second fluid path couples the return subtank with the supply subtank for circulating the ink from the return subtank back to the supply subtank. This way a closed ink circulation path is realized. The ink flow from the supply subtank to the inkjet printhead and to the return subtank is controlled by means of a pressure difference between the ink in the supply subtank and the ink in the return subtank. A back pressure at the nozzle of the inkjet printhead is established via active pressure control means.

Abstract: An ink circulation system for use in an inkjet printing apparatus includes an inkjet printhead, an ink supply path for supplying an ink to the inkjet printhead and an ink return path for returning ink not used for printing from the inkjet printhead. The ink return path is coupled to the ink supply path for replenishing the ink supply path with the ink returned from the printhead. The coupling establishes an ink circulation circuit. The ink circulation circuit can be replenished with fresh ink from a main tank, as ink is withdrawn by the printhead for printing. In the circulation system an active through-flow ink degassing unit is provided to control the dissolved gas level of the ink in the ink circulation system.

Abstract: An ink system for use in an inkjet printing apparatus includes an inkjet printhead, a supply subtank for containing a supply of an ink to the inkjet printhead, and a return subtank for containing a surplus of the ink not used by the inkjet printhead. A first fluid path couples the supply subtank with the inkjet printhead and with the return subtank, and provides a flow of ink from the supply subtank to the inkjet printhead and to the return subtank. A second fluid path couples the return subtank with the supply subtank and feeds the ink from the return subtank back to the supply subtank. The ink system is characterised by having the supply subtank, the return subtank and the first fluid path supported on a carriage for reciprocating together with the inkjet printhead across the printing medium.