| 摘要 |
A series of printheads used in a piezoelectric inkjet drop on demand (DOD) printer are supplied with ink. The required ink pressure at the printhead is adjusted via a closed loop involving the reading of pressure sensors 7 and 8 and the consequent regulating and adjusting of proportional valves VP1 and VP2 16 and 17 , to obtain the desired ink supply pressure. The negative pressure or vacuum and ink flowrate control and adjustment are achieved by the use of a pressure sensor or transducer 9 in a closed loop with a proportional valve VP2 . Two positive displacement diaphragm pumps 2 and 15 are operated at a constant motor speed, controlling the supply and return of ink respectively. Spring loaded diaphragm dampers 3 and 11 may also be fitted to reduce fluctuations in the pressure and vacuum levels. The ink may be heated using heater 4 and filtered by using filter 6. The system may also incorporate an ink storage tank 1 and a further ink reservoir 14 having a filter 13 therein. Flexible umbilical leads may be used to connect the various components together. |
