Abstract: An ion generator for the formation of electrostatic images, including two electrodes at opposite faces of a solid dielectric member, using a threshold multiplexing principle for the drive circuit. The apparatus provides a drive signal to each electrode to generate ions in an air region adjacent one of the electrodes, which ions are extracted for electrostatic imaging. Two drive signals each consisting of a sinusoidal alternating potential, out of phase by 180.degree., intermittently induce the production and extraction of ions. Other time-varying potentials of like electrical characteristics may be used, providing a number of operating advantages. The ion generator produces ions only during print periods, and requires reduced power to achieve given ion outputs. The control electrode may be partially encapsulated to limit the discharge region. Drive circuitry such as low source impedance gated oscillators, or other low impedance drivers, reduce capacitive "cross-talk" in a multielectrode device.

Abstract: Dielectric sealing of porous anodized aluminum, in which moisture in the pores of the oxide coating formed by hardcoat anodizing is removed, and the porous anodized surface then impregnated with a dielectric wax. Suitable wax sealants include Carnauba and Montan waxes. The anodized member is preliminarily heated to a temperature in the range 120.degree.-180.degree. C. in order to drive off moisture and other substances from the pores. This heating process may be continued for the purposes of impregnating the pores with the wax sealant, which is applied as a hot melt. Alternatively, the preliminary dehydration is achieved simply by heating the member to the impregnating temperature, with no separate dehydration stage. Any excess material remaining on the member's surface is removed. The resulting product has excellent resistivity and dielectric properties, and maintains these properties at elevated humidities.

Abstract: A corona charging device including a dielectric-coated elongate conductor contacting or closely spaced from a grid electrode, mounted against an insulating support. A high voltage varying potential between the elongate conductor and grid electrode induces a glow discharge in the vicinity of the dielectric-coated electrode. The grid electrode may act as a ground plane to provide a corona discharge device with respect to a proximate member. Alternatively, the grid electrode may be maintained at a desired potential to provide a charging device with an automatically limited voltage.

Abstract: An electrostatic imaging device including an elongate conductor coated with a dielectric, and a transversely oriented conductor contacting or closely spaced from the dielectric-coated conductor. A varying potential between the two conductors results in the formation of a pool of ions of both polarities near the crossover area. Ions are selectively extracted by means of an extraction potential to form a discrete, well-defined charge image on a receptor surface.

Abstract: Method and apparatus for ion generation with enhanced performance through operation at elevation temperatures. A glow discharge ion generator is subjected to extrinsic heating, both preliminarily and during continued operation, thereby providing increased ion current outputs. Such thermal control additionally prolongs the life of the ion generator by reducing corrosion and contaminant buildup.

Abstract: A corona charging device including a dielectric-coated elongate conductor contacting or closely spaced from a grid electrode, mounted against an insulating support. A high voltage varying potential between the elongate conductor and grid electrode induces a glow discharge in the vicinity of the dielectric-coated electrode. The grid electrode may act as a ground plane to provide a corona discharge device with respect to a proximate member. Alternatively, the grid electrode may be maintained at a desired potential to provide a charging device with an automatically limited voltage.

Abstract: Electrostatic transfer printing in which a latent electrostatic image is formed on a cylindrical dielectrical member by means of a glow discharge ion source. The image is then toned and pressure-transferred to a receptor, such as a sheet of paper, which is passed between the cylindrical dielectric member and a transfer roller. Scraper blades may be included to remove residual toner from the cylindrical dielectric member and the transfer roller. Means may also be included to erase any latent residual electrostatic image on the cylindrical dielectric member.

Abstract: Charge transfer imaging method and apparatus using a photoreceptor assembly. The assembly, which is formed by the interposition of a semiconducting substrate between a photoreceptor and a conducting base member, is used to transfer an image to a dielectric member with reduced image degradation.

Abstract: Electrostatic transfer printing in which a latent electrostatic image is formed on a cylindrical dielectrical member by means of a remote glow discharge ion source. The image is then toned and pressure-transferred to a receptor, such as a sheet of paper, which is passed between the cylindrical dielectric member and a transfer roller. Scraper blades may be included to remove residual toner from the cylindrical dielectric member and the transfer roller. Means may also be included to erase any latent residual electrostatic image on the cylindrical dielectric member.

Abstract: An electrophotographic system employing double image transfer. A photoconductive member is charged and exposed to form a latent electrostatic image, which is then transferred to a drum with a durable dielectric coating. The latent electrostatic image is subsequently toned and transferred by pressure to a recording medium, with or without simultaneous pressure fixing.

Abstract: Generation of charged particles, e.g. ions, by extracting them from a high density source provided by an electrical gas breakdown in an electric field between two conducting electrodes separated by an insulator. When a high frequency electric field is applied, surprisingly high ion current densities can be obtained, providing numerous advantages over conventional ion forming techniques for use in electrostatic printing and office copying, as well as in electrostatic discharging, precipitation, separation, and coating.

Abstract: A printing apparatus for generating visible bar code images in accordance with an electronic input command which comprises: a conducting mask containing a slot, a fine diameter ion emitting wire positioned on one side of the mask and adjacent to this slot and an electrically conductive support member. An insulating latent charge image receiving member is transported at a uniform velocity while spaced a short distance from the slotted mask and on the side of the mask opposite the side to which the ion emitting wire is adjacent. A potential is applied between the slotted mask and the conducting support member upon which the insulating member rests. Conventional means are provided for electrostatically toning the latent image formed on the insulating surface and additional means are provided for fixing the toned image. Transport means are provided to move the insulating member, at a uniform velocity, through the latent image forming, toning, and fixing stations.