Patent ID: 7641120

Claim:
A system for embedding and recovering machine readable information on an image receiving substrate, comprising: an image forming device containing at least two fluorescent marking materials, wherein the at least two fluorescent marking materials comprise a first fluorescent marking material containing a first fluorescent material so that upon exposure to radiation effecting fluorescence of the first fluorescent material, the first fluorescent marking material exhibits a first visible color, and a second fluorescent marking material containing a second fluorescent material so that upon exposure to radiation effecting fluorescence of the second fluorescent material, the second fluorescent marking material exhibits a second visible color different from the first visible color, wherein the image forming device receives data representative of the machine readable information, and forms an image corresponding to the data in a machine readable code format with the first fluorescent marking material and/or second fluorescent marking material on the substrate, wherein the machine readable code format is comprised of a set of distinguishable symbols including a first symbol and a second symbol, the first symbol and the second symbol respectively encoding a first set of digital values comprised of a first digital value and a second digital value selected from the group consisting of zeroes and ones, on the substrate with the at least two fluorescent marking materials, wherein the distinguishable symbols are selected from a group consisting of glyphs and dots, wherein if the first digital value is a zero, the second digital value is a zero or a one, and if the first digital value is a one, the second digital value is a zero or a one, wherein the first visible color and the second visible color respectively encode a second set of digital values selected from the group consisting of zeroes and ones, wherein if the first visible color encodes a zero, the second visible color encodes a one, and if the first visible color encodes a one, the second visible color encodes a zero, wherein the first symbol is formed by one of either the first fluorescent material or the second fluorescent material and the second symbol is formed by the other of the first fluorescent material or the second fluorescent material. and a document reading device including a radiation emitting unit that emits radiation effecting fluorescence of the first fluorescent marking material and/or second fluorescent marking material, and a reader that detects the data in the image on the image receiving substrate while the first fluorescent marking material and/or second fluorescent marking material is fluorescing.