Abstract: Method and apparatus for eliminating stray background toner in electrostatic printer images by first electrostatically neutralizing any background toner charge and then removing neutralized toner. An ac corona wire positioned between a developer unit and a background toner scavenger is employed to neutralize unwanted background toner. Alternately, a high current density ac discharge between two electrodes separated by a dielectric layer may be employed as a bipolar ion source. Toner may be scavenged using either a vacuum suction manifold and/or a rotating brush.

Abstract: A method and apparatus for driving inductive elements, such as deflection coils for a CRT, including a resonant bus, a bus capacitor, and at least two inductive branches grouped in a pair and connected to the bus, each inductive pair including serially-connected one of the inductive elements and a diode means, the diode means in one branch being connected in reverse direction relative to the other diode in the other branch to allow current flow in the one branch to flow from the resonant bus and to allow current flow in the other branch to flow to the resonant bus to produce a sine-squared current in each of the branches inverted with respect to the other and to produce a sinusoidal current in the bus capacitor.

Abstract: The image receiving surface of a non-impact image printer such as an electrographic printer is treated with an AC corona just prior to image transfer to paper or the like thereby to suppress transfer of non-image background toner and edge effect toner thereby to enhance the transferred image.

Abstract: An endless loop multi layered belt for an electrographic printer is supported on a plurality of rollers and driven by sprocket holes along one belt edge, the belt having coextensive conductive and charge receiving layers. Another embodiment provides a conductive endless strip along the other lateral edge to maintain electrical contact with the conductive layer and a further embodiment provides support for the belt system.

Abstract: A belt conditioner for non-impact electrographic printing apparatus using a flexible dielectric belt (including a conductive member forming a ground plane opposite the dielectric surface) has plural electrically conductive rollers engaging the dielectric charge receiving surface to effect controlled discharge of the surface to a uniform surface electrostatic voltage before direct charge deposition by a print head to form a latent electrostatic image. Corona discharge devices can also be utilized with the rollers to obtain the desired belt conditioning.

Abstract: In electrographic printing apparatus, a charge transfer endless-loop dielectric belt including a conductive member to effect a ground plant is supported to tension with an unsupported portion thereof disposed opposite the electrodes of the print head. The unsupported portion results from belt engagement with the printhead in regions adjacent to the electrodes to provide the desired electrode/dielectric belt spacing.

Abstract: A controlling electrode is positioned in physical proximity to one or more electrodes in an electron beam tube so that the controlling and controlled electrodes are subject to common electron bombardment. A control voltage of preselected magnitude and polarity is applied to the controlling electrode. During the common electron bombardment, primary and secondary electrons are present in the region of the electrodes, an exchange of electrons occurs between the electrodes, and the voltage on the controlled electrodes switches to a value at or near the voltage applied to the controlling electrode. The electron beam tube can be a cathode ray pin tube used in electrostatic printing in which case a single controlling electrode is positioned in proximity to the array of conductive pins in the tube face plate.

Abstract: Image formation and development apparatus using electrostatic techniques which is suitable for plain paper printing is provided wherein a cathode ray pin tube is used with a flexible discontinuous dielectric member that is moved past the pin tube, the selectively energized pins providing information-bearing areas (i.e. toner attracting areas) on the dielectric member; the latent electrostatic image is developed and may thereafter to transferred to plain paper and fixed for subsequent use. The apparatus includes pin tube cleaning means operative when the belt discontinuity passes the pin tube face.