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A DUAL WAVELENGTH SCANNING SYSTEM

IP.com Disclosure Number: IPCOM000024824D
Original Publication Date: 1982-Apr-30
Included in the Prior Art Database: 2004-Apr-04
Document File: 2 page(s) / 108K

Publishing Venue

Xerox Disclosure Journal

Abstract

In dual function xerographic type copiers capable of producing copies either through exposure of document originals on thexopier platen or by means of a laser generated flying spot beam scanning across the copier photoreceptor to expose the photoreceptor in accordance with video image signals, a third function may be envisioned; namely, scanning the toner image on the photoreceptor with the flying spot beam and converting the light reflected therefrom to video image signals. This later function depends upon specular or total reflection from the photo-receptor surface of a laser beam. The wavelength of the laser beam is chosen for the second function, i.e., a wavelength suitable to cause the beam to be absorbed by the photoreceptor to cause discharge.

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XEROX DISCLOSURE JOURNAL

A DUAL WAVELENGTH SCANNING SYSTEM Proposed Christopher Snelling U.S. C1. 358/285 Classification

Int. C1. H04n 1/04

SHORT WAVELENGTH BEAM

\'

EXPOSURE

SCANNING

           SUBS TRATE PHOTORECEPTOR

LONG WAVELENGTH BEAM

/ J / TONER IMAGE \ / \ /

I

\ /

\I ELECTROPOLISHED

\,,'

4 INTERFACE

SCANNING

       SUBSTRATE PHOTORECEPTOR

In dual function xerographic type copiers capable of producing copies either through exposure of document originals on thexopier platen or by means of a laser generated flying spot beam scanning across the copier photoreceptor to expose the photoreceptor in accordance with video image signals, a third function may be envisioned; namely, scanning the toner image on the photoreceptor with the flying spot beam and converting the light reflected therefrom to video image signals. This later function depends upon specular or total reflection from the photo- receptor surface of a laser beam. The wavelength of the laser beam is chosen for the second function, i.e., a wavelength suitable to cause the beam to be absorbed by the photoreceptor to cause discharge.

A concern exists for the practical achievability of defect-free photoreceptor surfaces, particularly alloy photoreceptors, because of occasional inclusions such as chips and flakes as part of the vacuum coating process normally used to produce this type of photoreceptor. In addition, process induced scratches are an anticipated source of performance degradation and toner image scanning is more sensitive to these inclusions/surface artifacts than normal xerographic copying since for a typical line copy image only 5% cf the photoreceptor surface area is image, whereas for toner image scanning of the same image the other 95% must be properly reflected.

Volume 7 Number 2 March/April 1982 117

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A DUAL WAVELENGTH SCANNING SYSTEM (Cont'd)

While photoreceptor surfaces may...