| 摘要 |
<p>DUAL MODE APPARATUS FOR DEVELOPING LATENT ELECTROSTATIC IMAGES Powder cloud development apparatus for developing latent electrostatic images on the surface of 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 insulating member, the baffle extending between the opposed walls. 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, being formed between selected ones of said wires, the wires being connected at each end to a continuous loop drive mechanism. In the negative development mode, the drive mechanism is energized, the development electrode thereby being driven past the insulating surface, the upper plane of the wire travel being closely spaced from the insulating surface. The wires are electrically biased in the development area and the wire to wire spacing with respect to wire diameter is sufficiently large to allow the passage of toner therethrough. The portion of the electrode which is not in the image area adjacent the insulating surface is movably directed in a manner whereby there is no interference with development. A stationary cleaning system, located without the development area, cleans the wires as they are directed therethrough. The drive mechanism may be connected to a variable speed device to allow optimization of the electrode speed. In the positive mode of operation, the drive mechanism is not energized and the development electrode is positioned whereby the gap is substantially coextensive with the insulating surface. A movable cleaning system for cleaning the upper surface of the baffle and the bottom of the development chamber is also provided.</p> |
