Abstract: This invention relates to sensitive or classified documents utilizing specially prepared paper containing a unique substance which will, in the presence of sensors incorporated within a document copier which constantly monitor the field of view for the presence of this unique substance, interrupt the operation of this document copier. Within the copier housing, adjacent the illumination and optical apparatus, a lens gathers some of the reflected light from a document to be copied. This light is then passed through three (3) narrow band spectral filters to three (3) associated detectors. Subsequent circuitry responds to the detected light at the predetermined wavelengths, if present, and, when appropriate, interrupts the operation of the copier and/or sounds an alarm or triggers a camera.

Abstract: Method and apparatus are disclosed for the prevention of unauthorized copying of documentation on an office, or other type, copier. Unique phosphors are applied to paper. When such a paper is placed on or in a copier so prepared, the presence of the phosphor is detected and the copier is disabled. Inside the copier a laser emits a beam toward the paper. Two detectors detect, respectively, the laser light reflected from the document and the stimulated light from the phosphor coating or layer. Detection of both signals, in the proper time sequence, will cause the photocopier to cease operation prior to electrostatic or other capture of the image. Upconversion phosphors could be utilized as the phosphor coating due to their scarcity and unliklihood of use in this manner.

Abstract: Method and apparatus are disclosed for the prevention of unauthorized copying of documentation on an office, or other type, copier. Unique phosphors are applied to paper. When such a paper is placed on or in a copier so prepared, the presence of the phosphor is detected and the copier is disabled. Inside the copier a laser emits a beam toward the paper. Two detectors detect, respectively, the laser light reflected from the document and the stimulated light from the phosphor coating or layer. Detection of both signals, in the proper time sequence, will cause the photocopier to cease operation prior to electrostatic or other capture of the image. Upconversion phosphors could be utilized as the phosphor coating due to their scarcity and unliklihood of use in this manner.