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PREVENTION OF COPYING COPYRIGHTED DOCUMENTS

IP.com Disclosure Number: IPCOM000023944D
Original Publication Date: 1979-Apr-30
Included in the Prior Art Database: 2004-Apr-01
Document File: 2 page(s) / 374K

Publishing Venue

Xerox Disclosure Journal

Abstract

By providing a special transparent electrode arrangement on the platen of an ordinary copying machine and appropriate signal and detection circuitry documents, copying of copyrighted documents placed on the platen of the machine can be prevented. The transparent platen is provided with an electrode arrangement on its surface. This arrangement can be fabricated from a transparent film comprising a dielectric base and a very thin conductive overlayer to form the interleave electrodes A and B. The transparency of the film, as applied to the platen, is such that the electrode platen will not appear on a copy of an original document.

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XEROX DISCLOSURE JOURNAL

PREVENTION OF COPYING COPYRIGHTED DOCUMEftTS Roy 3. Lahr
David D. Thornburg

ELECTRODE A

Volume 4 Number 2 March/April 1979 273

Proposed Classification
U.S. CL 155/133

mt. CL G03b

By providing a special transparent electrode arrangement on the platen of an ordinary copying machine and appropriate signal and detection circuitry documents, copying of copyrighted documents placed on the platen of the machine can be prevented. The transparent platen is provided with an electrode arrangement on its surface. This arrangement can be fabricated from a transparent film comprising a dielectric base and a very thin conductive overlayer to form the interleave electrodes A and B. The transparency of the film, as applied to the platen, is such that the electrode platen will not appear on a copy of an original document.

Electrode A is connected to a signal source such as a square-wave generator. Electrode B is connected to detection circuitry comprising an amplitude detector, a threshold circuit and an amplifier. The output of the amplifier is connected to the control circuitry of the copier. If a signal is received from the amplifier, the copier operation is disrupted.

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PREVENTION OF COPYING COPYRIGHTED DOCUMENTS (ConVd)

The detection circuitry is made operative by placing a copyrighted document on the electrode arrangement of the platen. If a sheet resistivity of the paper comprising such...