Jet drop printer

Abstract

A jet drop printer for selectively depositing drops along a plurality of parallel lines on a moving print receiving medium includes a print head for generating a plurality of jet drop streams directed toward the moving print receiving medium, with the streams arranged in a row substantially perpendicular to the direction of movement of the print receiving medium. A drop charging electrode arrangement, adjacent each of the jet drop streams, selectively charges drops in each of the streams to one of a plurality of discrete charge levels. A deflection means provides a plurality of static drop deflecting electrostatic fields, with each of the jet drop streams passing through an associated one of the fields. Each drop deflecting field deflects charged drops passing therethrough in a direction which is inclined with respect to the row of jet drop streams and with respect to the direction of movement of the print receiving medium. Each drop in the jet drop streams is deflected by a distance dependent upon the charge carried by the drop. A drop catcher means positioned adjacent the row of drop streams and extending substantially parallel thereto, catches drops from each of the drop streams which are sufficiently deflected. The deflection means may include a plurality of parallel lateral deflection electrodes for providing first static electrical deflection fields extending substantially parallel to the row of jet drop streams and a longitudinal deflection electrode for providing a second static electrical deflection field extending substantially perpendicular to the row of jet drop streams. Alternatively, the deflection means may comprise a plurality of pairs of parallel deflection electrodes extending obliquely with respect to the row of jet drop streams.