| 摘要 |
PURPOSE:To improve the rising characteristic of head-side pressure upon starting of driving of an air source and thereby to avoid back flow of ink by provision of a passage on-off device and an initial-pressure regulator valve in an air supply system for flying ink droplets together with an air flow. CONSTITUTION:An air flow from an air source 14 is regulated by a head-side pressure regulator valve 17, fed into an air chamber 7, and discharged from an air discharge port 8 to assist ink droplets in flying. On the other hand, a portion of the air flow is fed into an ink reservoir 20 after regulated by an ink reservoir pressure regulator valve 18 and an air vent regulator valve 19, to apply a pressure to ink. In this device, upon starting of driving of the air source 14, the rise time of head- side pressure relative to ink reservoir pressure is so short that ink flows back. To avoid this, there are provided a passage on-off device 29, timing regulator valve 30, and pressure sensor 31 to regulate the rise time of the head-side pressure upon starting of driving of the air source 14. |
