STELSEL MET EEN REGELDRUKINRICHTING.

摘要

A line printing apparatus in which spot patterns of ink or toner particles are formed on a moving paper sheet. A modulator defined by a corona source and an electric shield which has a multiplicity of linearly arranged apertures is spaced from one side of the paper. The voltage at each aperture is individually controlled so that ions from the corona are permitted or prevented from passing through preselected apertures. The passing ions impinge certain particles in a toner particle cloud between the modulator and the one side of the paper sheet. A paper support bar is positioned on the other side of the paper and constructed of an insulator and an elongate electrode is secured to the back side of the insulator and positioned parallel to the aperture array. Lateral sides of the insulator are grounded and a high voltage applied to the electrode results in a high surface voltage on the paper support surface of the insulator which gradually drops off to zero or opposite potential from a maximum along a line aligned with the aperture array to the lateral sides of the insulator. Those toner particles impinged by ions are attracted to the high surface voltage on the insulator and deposited on the side of the sheet facing the modulator to sequentially form spot patterns and generate a line print. In one embodiment, the paper support bar is stationary and the paper sheet slides across its surface. In another embodiment, the paper support bar is a rotatable cylinder, preferably supported by rotatable support cylinders with electrically insulative surfaces.