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Presensitization of Organic Electrophotographic Layers by Exposure or Polarization and Exposure

IP.com Disclosure Number: IPCOM000095199D
Original Publication Date: 1965-Oct-01
Included in the Prior Art Database: 2005-Mar-07
Document File: 1 page(s) / 12K

Publishing Venue

IBM

Related People

Shattuck, MD: AUTHOR [+2]

Abstract

In order to have fast electrophotographic speed, it is necessary that the photoconductor have a high discharge rate. Increase in discharge rate can be obtained if the organic photoconductor is first uniformly exposed or uniformly charged and exposed prior to being exposed to the image. This is, in effect, a presensitization of the photoconductor. For example, after heating or sufficient dark adaption, the photoconductor is uniformly charged by a corona unit followed by a uniform exposure. Once being presensitized, the photoconductor again is charged with the corona unit, but this time is subjected to an imagewise exposure. The latent electrostatic charge pattern thus created can be developed with toner in the usual manner or transferred to a dielectric sheet and developed on the sheet.

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Presensitization of Organic Electrophotographic Layers by Exposure or Polarization and Exposure

In order to have fast electrophotographic speed, it is necessary that the photoconductor have a high discharge rate. Increase in discharge rate can be obtained if the organic photoconductor is first uniformly exposed or uniformly charged and exposed prior to being exposed to the image. This is, in effect, a presensitization of the photoconductor. For example, after heating or sufficient dark adaption, the photoconductor is uniformly charged by a corona unit followed by a uniform exposure. Once being presensitized, the photoconductor again is charged with the corona unit, but this time is subjected to an imagewise exposure. The latent electrostatic charge pattern thus created can be developed with toner in the usual manner or transferred to a dielectric sheet and developed on the sheet.

Organic photoconductors operate most effectively with weakly-absorbed radiation. This generates charge carriers or conductivity sites throughout the photoconductor. Therefore, the exposure step of the presensitization should be with weakly absorbed radiation and the subsequent imagewise exposure with strongly absorbed radiation. In this way, the sensitivity of the photoconductor to strongly absorbed radiation can be increased. The following illustrate the effect on the electrophotographic speed of the photoconductor when it is presensitized.

Polyvinylcarbazole sensitized with 20 percent...