Browse Prior Art Database

Secure Document Feature for Copy Machines

IP.com Disclosure Number: IPCOM000084028D
Original Publication Date: 1975-Sep-01
Included in the Prior Art Database: 2005-Mar-02
Document File: 1 page(s) / 12K

Publishing Venue

IBM

Related People

Bacon, JL: AUTHOR [+2]

Abstract

The IBM Technical Disclosure Bulletin, Vol. 15, No. 9, February 1973, at pages 2736 and 2737 describes an electrophotographic copying apparatus whose document glass includes a conductive grid pattern, whose electrical capacitance changes when a conductive document is placed thereon. Information which is not to be copied is recorded on this special conductive paper, to form a secure original document which cannot be copied.

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Secure Document Feature for Copy Machines

The IBM Technical Disclosure Bulletin, Vol. 15, No. 9, February 1973, at pages 2736 and 2737 describes an electrophotographic copying apparatus whose document glass includes a conductive grid pattern, whose electrical capacitance changes when a conductive document is placed thereon. Information which is not to be copied is recorded on this special conductive paper, to form a secure original document which cannot be copied.

With this system, the possibility exists that the depth of focus of the copier's lens may be such that a secure original document can be hand-held off the document glass, and out of range of the capacitance sensor. While this can be prevented by the use of a lens having a short depth of focus, or by a sharply focused illumination system, or by a copier construction which requires that a document flap be closed over the original before the copier will operate, it is preferable to provide a document glass whose top, original-engaging surface is diffused or frosted.

This surface may be obtained by chemical etching, shot blasting, or overcoating with a diffusing polymer. When this is done, a hand-held document, held slightly above the document glass, results in a badly blurred copy, and yet a copy made with an original placed in contact with the document glass is not noticeably degraded.

In addition, it may be desirable to use conductive paper having a subtle background pattern, since this background patter...