Droplet control aspects--ink evaporation reduction; low voltage contact angle control device; droplet trajectory release modes; uses for metallic ink drops in circuit wiring and press printing

摘要

In ink drop printers wherein a portion of the propelled ink from an orifice is returned for reuse and other ink selected from the issuing ink filament proceeds to an ink receiving surface, a cover is disclosed, which substantially prevents gas from leaving the selection region, unless the exiting gas or a substantially solvent saturated replacement gas is returned after ink is extracted for reuse. Thus, except for an ink extraction route, mist, satellite drops, exploded drops, evaporated solvent, and unused drops, whichever are present, are substantially prevented from leaving the cover; whereas, print droplets do leave the cover. Problems solved are ink solvent replacement, ink drying on printer surfaces such as orifices, dust entry to electrostatic areas, and external ink build up and messiness. Electrodes, or gas passing thereover, may be heated slightly to prevent solvent condensation. PP Features of a selection system having no electrodes, except those washed by ink droplets are disclosed. Application of electrical voltages changes the contact angle of selected droplets, thus pulling them closer to a surface. Other droplets with the same initial conditions but to which less voltage is applied travel other paths and leave the surface at other positions. Contact configurations and departure modes are disclosed. PPThe third aspect of this invention deals with voltages and the formation of conducting areas covered with a dielectric and having an exposed surface upon which a selected ink, possibly metallic, will form a reasonably large contact angle. A hydrophobic layer may be added above a high voltage dielectric.