Abstract: Powder cloud development apparatus for developing latent electrostatic images on an insulating member, such as a photoconductive layer, wherein a cloud of charged developer particles is introduced into the development chamber through a first port in the chamber wall and air is introduced through a second port in the chamber wall opposite said first port. A baffle is positioned above the ports and below the surface of the insulator, the baffle extending between the opposed walls. A development electrode comprising a series of parallel wires, electrically biased in the development area, is connected at each end to a continuous loop drive mechanism, the upper plane of the grid wire being closely spaced from the insulator surface. The wire to wire spacing with respect to wire diameter is sufficiently large to allow the passage of toner therethrough.

Abstract: A powder cloud development apparatus is provided for developing latent electrostatic images on the surface of an insulating member, normally a photoconductive layer, employing a powder cloud development system. The development apparatus is operable in either a positive or negative mode and includes a development electrode comprising a plurality of spaced substantially parallel wires, a gap, or open section, which is formed between selected groups of these wires, the wires being connected at each end to a continuous loop drive mechanism. The parallel wires therefore or the gap may either be presented in operable relationship to the surface of the insulating member in order to provide either electroded or non-electroded development in the negative and positive modes respectively.