| 摘要 |
<p>Drop selection by surface tension reduction is a drop-on-demand printing mechanism in which ink in a liquid state is retained in a printing nozzle at a pressure greater than atmospheric pressure, but insufficient to overcome the quiescent temperature surface tension of the ink and expel the ink from the nozzle. The surface tension of the ink decreases with increasing temperature, and the nozzle includes an electrically activated means of heating the ink to a temperature less than the boiling point of the ink. The surface tension reduces to a value insufficient to retain the ink in the nozzle, whereby a drop of the ink emerges from the nozzle. An ink composition is disclosed which has the property of a large reduction of surface tension with increasing temperature. The ink is based on a microemulsion with a phase inversion temperature around the desired drop ejection temperature. At the phase inversion temperature, the microemulsion forms a bicontinuous structure between the oil and water components of the ink. At this temperature, the surfactant has a high affinity for surfaces of low curvature, and therefore migrates to the ink/air interface, lowering the surface tension.</p> |
