| 摘要 |
PURPOSE:To prevent the excessive recession of ink from an orifice by applying bias heating when the voltage pulse given to a heating element falls in a pressure-control- type ink jet head wherein thermal energy is utilized. CONSTITUTION:When a driving pulse is given to a heating element HI, an air bubble B is produced, which increases the pressure in a tiny liquid chamber W and make liquid drips be discharged from an orifice OF. When the pulse disappears, the volume of the air bubble contracts and the liquid drip is made to fly due to fatigue. After that, when the air bubble further contracts, the surface of the liquid IM recedes to the inside of the end surface of the orifice. At this time, sudden recession causes excessive entering of the air into the orifice and this prevents the discharge thereof by the pulse to follow. If the pulse is devised to have a form so that it applies bias heating at the time of its falling the heating element is cooled gradually and the liquid-drip is separated smoothly. |
