| 摘要 |
A viscoelastic and ink-immiscible fluid is used to form a membrane over the ink orifice of a drop-on-demand, pressure pulse ink jet head. The membrane lies in a plane perpendicular to the direction of emission of ink drops, and provides a barrier between the ink orifice and the external atmosphere. Evaporation of the ink, or entry of contaminants including air into the ink, is thus inhibited. The elimination of evaporative clogging then permits the use of a smaller orifice. Wetting of the exterior surface of the ink jet head by the flow of ink through the ink orifice is also inhibited, thus making possible the production of more uniform ink drops that will emerge in a constant direction. The elastic property of the membrane permits the passage of an ink drop therethrough, followed by the closing up of the membrane. The viscous property of the membrane permits it to absorb any energy of a pressure pulse that is not consumed in ejecting an ink drop, thus inhibiting the occurrence of pressure oscillations that could cause either variations in the speed of ejected ink drops or the appearance of satellite ink droplets.
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