Patent ID: 7633651
Filing Date: 2009-12-15
Classification: B41M,C09D,G07D,H04N

Abstract:
1. A method of generating a non-reproducible printed image on a document including a conventionally printed image, the method comprising the steps of: applying a first, background layer of a first ink that has little or no carbon content, which has a dark color and absorbs visible light but reflects light of a predetermined wavelength or range of wavelengths, to a portion of a substrate in a preprocessing step; and printing said conventionally printed image, and printing the non-reproducible image on the background layer adjacent to said conventionally printed image using a second ink that has a high carbon content, which has a dark color that is visually indistinguishable from the first ink and absorbs both visible light and light of the wavelength or range of wavelengths in a document printing step, wherein said non-reproducible image is substantially invisible relative to the background layer under visible light, copying of the document by a conventional imaging device utilizing visible light can reproduce said conventionally printed image but cannot extract said non-reproducible image from the background layer, and the non-reproducible image becomes discernable by illumination of said non-reproducible image by light of the wavelength or range of wavelengths.