LOW COST, HIGH PRESSURE, HIGH FLOW VACUUM PUMP FOR USE IN INK JET PRINTERS
Original Publication Date: 1992-Jun-30
Included in the Prior Art Database: 2004-Apr-06
Xerox Disclosure Journal
In the Thermal Ink Jet (TIJ) technology, the printhead is primed by sucking ink from the printhead nozzles. During this priming operation, residue ink may be left on the face of the printhead due to the surface tension of the ink. If left uncleaned, this ink will lead to print quality problems. However, a cleaning pump design that supplies the required pressure, flow rate, and volume of air to the printhead face prevents ink residue from accumulating. A sketch of a cross-sectional view of such a pump 10 is shown in the accompanying Figure. A collapsible bellows 12 coupled with a small articulating diaphragm pump 14 is used. The bellows can be viewed as an air volume capacitor because it is loaded by the low flow, high pressure diaphragm pump and then released on command by solenoid valve 16, when face cleaning is required. The bellows can also be loaded simply with a mechanical device, but the diaphragm 18 was found to be a very low cost device. The flow rate of the pump can be tailored to the individual application by increasing the spring force of the bellows, but this also requires increasing the pressure of the diaphragm pump.