摘要 |
PURPOSE:To prevent air from being sucked into an ink jet head from a nozzle by reducing the pressure of ink to be fed under pressure beyond the limit of ink pressure at time of recording and then set the ink pressure at the level of atmospheric pressure. CONSTITUTION:The ink pressure is detected by means of a pressure control device 20 and then a discharge pressure on an ink pressurizing pump 8 is controlled by means of a pressure control circuit 21. When a switching valve 22 is opened, an accumulated pressure is released to recover the ink into an ink tank 7. When recording is stopped, the valve 22 is opened following a condition that a switching valve 12 is opened and the valve 22 is closed. At the same time, a desired pressure drop is detected by means of the pressure control device 20. Next, the switching valve 12 is closed (the atmospheric pressure is released) and the switching valve 22 is closed. |