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Improved Dynamic Range in the Scanning Function for Electrophotographic Laser Printer/Scanner

IP.com Disclosure Number: IPCOM000043922D
Original Publication Date: 1984-Oct-01
Included in the Prior Art Database: 2005-Feb-05
Document File: 2 page(s) / 32K

Publishing Venue

IBM

Related People

Balanson, R: AUTHOR [+4]

Abstract

An electrophotographic printer/scanner is produced by monitoring a scanning laser beam reflected from the toned photoconductor surface. By employing a laser wavelength for the scanning function, chosen to lie in the transparent region of the photoconductor, the intensity and dynamic range of the reflected signal are greatly enhanced. The electrophotographic printer/scanner accomplishes printing by modulating a scanning laser beam on and off to selectively discharge areas of the previously uniformly charged photoconductor, thereby yielding a latent charge image. This image is subsequently developed to produce a toned image. Scanning is performed on the toned image by a laser beam which utilizes the same optical system as that used for the printing function to deflect the beam.

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Improved Dynamic Range in the Scanning Function for Electrophotographic Laser Printer/Scanner

An electrophotographic printer/scanner is produced by monitoring a scanning laser beam reflected from the toned photoconductor surface. By employing a laser wavelength for the scanning function, chosen to lie in the transparent region of the photoconductor, the intensity and dynamic range of the reflected signal are greatly enhanced. The electrophotographic printer/scanner accomplishes printing by modulating a scanning laser beam on and off to selectively discharge areas of the previously uniformly charged photoconductor, thereby yielding a latent charge image. This image is subsequently developed to produce a toned image. Scanning is performed on the toned image by a laser beam which utilizes the same optical system as that used for the printing function to deflect the beam. In conventional systems, in the scanning mode, the toned areas tend to scatter or absorb light while the untoned areas tend to specularly reflect the scanning beam. In this system, since the laser must lie in the absorbing region of the photoconductor to accomplish the printing, the intensity of the reflected radiation is rather weak. In addition, as shown in the figure, the radiation R1 is reflected from the surface of the photoconductor while radiation R2 is reflected from the conductive backing (aluminum, for example). The two reflected radiation components R1 and R2 may interfere so that the tot...