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"No Copy" Attachment for Copier

IP.com Disclosure Number: IPCOM000083272D
Original Publication Date: 1975-Apr-01
Included in the Prior Art Database: 2005-Mar-01
Document File: 3 page(s) / 55K

Publishing Venue

IBM

Related People

Harr, JD: AUTHOR [+3]

Abstract

This system is arranged to prevent the copying of predetermined documents on a copier modified to sense the presence of the document.

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"No Copy" Attachment for Copier

This system is arranged to prevent the copying of predetermined documents on a copier modified to sense the presence of the document.

A document has a flourescent material deposited in or on it which is invisible under normal lighting, but which fluoresces red under long wavelength ultraviolet radiation. The fluorescent material may be a mixture of (Zn + Cd)S with Ag, or with Cu as the activator. Red emitting fluorescent materials are Eu(2)(WO(4))(3); Y(2)(VO(4))(3) Eu; ZnCdS Ag; MgO GeO(2): Mn; and CaS Eu: NaCl.

Other materials are known for the purpose, responding to ultraviolet or other radiation. Organic material such as rubrene and the porphyrines may also be considered for this purpose. The fluorescent material may be deposited in the paper during manufacture, coated on the paper during manufacture or later, or deposited in the printing process, as by typewriter ribbons, spirit duplicators, or printing inks laid down by rubber stamps, type or lithographic presses and the like.

In Fig. 1, a document 10 is placed in the copier, not shown, over a lens system 12 and illuminated by lamps 14,14 in the conventional manner for copying. Prior to or during the copying process, ultraviolet light is projected onto the face of the document 10, as by the lamps 14,14 or a separate ultraviolet source.

Flourescence obtaining from the excitation of the proper wavelength of light - as by the ultraviolet light in the example, is sensed by a pair of detectors 16,16 capable of sensing light of the emitted wavelength. An amplifier circuit arrangement 20 comprising transistors 22,24 and 26 is connected to the sensors 16,16. A variable resistor 28 is adjusted to obtain optimum results.

The amplifier circuit 20 is energized through connections to the power circuit of the copier. Power at terminals 30 is applied by closing a push-button switch 32 to the winding of a relay 34. Normally, the contacts of the relay 34 are connected to apply power through the arm and normally closed contacts of a "paper out-document sense" relay 36 to...