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Document Transport Mechanism for Optical Scanning

IP.com Disclosure Number: IPCOM000079079D
Original Publication Date: 1973-May-01
Included in the Prior Art Database: 2005-Feb-26
Document File: 2 page(s) / 48K

Publishing Venue

IBM

Related People

Thorpe, RA: AUTHOR

Abstract

In a document transport mechanism for an optical scanning system, the thickness of object (scanned) documents may affect the quality of the scanned facsimile. The situation giving rise to this is illustrated in Fig. 1 and means for correction of this situation are shown in Fig. 2.

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Document Transport Mechanism for Optical Scanning

In a document transport mechanism for an optical scanning system, the thickness of object (scanned) documents may affect the quality of the scanned facsimile. The situation giving rise to this is illustrated in Fig. 1 and means for correction of this situation are shown in Fig. 2.

As indicated in Fig. 1, the document transport mechanism comprises a perforated drum rotating over one or more fixed vanes forming air-tight compartments. Alternate compartments are evacuated and pressurized to secure attraction and repulsion of the document. Documents fed onto the surface of the drum are thereby held to the drum by vacuum, and dispensed from the drum by positive outgoing pressure. The problem with this type of arrangement is that the distance from the surface of the document to an arbitrary reference line of the optical scanning system is a variable, which depends upon the planarity of the document surfaces and the thickness of the documents.

This variation in optical scanning distance is eliminated by the configuration shown in Fig. 2. Here the vanes are configured to apply vacuum to the document at a position preceding the optical scanning station, and positive releasing pressure to the document at the scanning station. A fixed holddown plate P, with a slit at the scanning station, positions the document surface to be scanned at a predetermined distance from the reference line of the optical system mentioned above, ir...