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Contact Electrostatic Printing

IP.com Disclosure Number: IPCOM000074182D
Original Publication Date: 1971-Mar-01
Included in the Prior Art Database: 2005-Feb-23
Document File: 2 page(s) / 52K

Publishing Venue

IBM

Related People

McCurry, RE: AUTHOR

Abstract

The formation of high quality electrostatic images is achieved by a technique in which a dielectric surface is precharged to a high potential of given polarity and thereafter selectively discharged. The reduction in surface charge is accomplished by mechanical means. Physical contact or near contact with a ground potential electrode provides a latent electrostatic image that is developed and transferred to ordinary paper by conventional techniques.

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Contact Electrostatic Printing

The formation of high quality electrostatic images is achieved by a technique in which a dielectric surface is precharged to a high potential of given polarity and thereafter selectively discharged. The reduction in surface charge is accomplished by mechanical means. Physical contact or near contact with a ground potential electrode provides a latent electrostatic image that is developed and transferred to ordinary paper by conventional techniques.

Figure A schematically shows the application of a shaped stylus, at ground potential, to the precharged surface of a dielectric supported by a conductor maintained at ground potential, the surface of the dielectric being precharged to approximately 1,000 volts. A suitable dielectric surface may be obtained by utilizing a plastic coated card. The stylus, when brought into physical contact with discrete areas of the precharged surface, causes these areas to be discharged, leaving discharged areas, that have the same configuration as that of the stylus, surrounded by the remaining precharged surface.

Figure B illustrates diagrammatically a high speed printer-recorder using the technique. The dielectric surface 1 on which the latent electrostatic image is to be written is coated on a grounded metal drum. The surface is charged to a uniform electrical potential by a corona charging unit 2. The latent image is formed by moving the styli into and out of contact with the drum surface at station
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