Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
61 words
1 An ink comprising a major portion of a carrier liquid that is capable of drying by evaporation and penetration of a substrate without leaving a residue that is sigificantly absorptive of radiation either in the visible or in the near infrared spectrum, and a minor portion of a fluorescent agent that fluoresces mostly in the near infrared spectrum of wavelengths.
Claim 2
Dependent Claim
61 words
1 An ink comprising a major portion of a carrier liquid that is capable of drying by evaporation and penetration of a substrate without leaving a residue that is sigificantly absorptive of radiation either in the visible or in the near infrared spectrum, and a minor portion of a fluorescent agent that fluoresces mostly in the near infrared spectrum of wavelengths.
Claim 3
Dependent Claim
18 words
2 An ink according to claim 1, in which the spectrum is of wavelengths between 650 and 800nm.
Claim 4
Dependent Claim
16 words
3 An ink according to claim 2, in which the fluorescent agent comprises a phenoxazine dye.
Claim 5
Dependent Claim
21 words
4 An ink according to claim 3, in which the phenoxazine dye is of the structure where X is the anion.
Claim 6
Dependent Claim
13 words
5 An ink according to claim 4, in which the anion is nitrate.
Claim 7
Dependent Claim
23 words
6 An ink according to any preceding claim, in which the dye concentration is about 0.35% by weight of the total ink solution.
Claim 8
Dependent Claim
20 words
7 An ink according to any preceding claim, in which the carrier liquid has a pH of 6 or less.
Claim 9
Dependent Claim
31 words
8 An ink according to any preceding claim, in which the ink vehicle comprises, as a major constituent thereof, a solvent selected from the group of water, methanol and ethylene glycol.
Claim 10
Dependent Claim
21 words
9 A system for marking items for subsequent automatic identification comprising printing means employing an ink according to any preceding claim.
Claim 11
Dependent Claim
17 words
10 A system according to claim 9, in which the printing means comprises an ink jet printer.
Claim 12
Dependent Claim
55 words
11 A method of automatically identifying ojects comprising the steps of marking the objects with characteristic indicia using an ink according to any of claims 1 to 8, subjecting the objects to exciting radiation that includes substantially no radiation in the near infrared spectrum, and selectively detecting only near infrared radiation emanating from the indicia.
Claim 13
Dependent Claim
51 words
12 A system for identifying indicia marked on an object with an ink according to any of claims 1 to 8, including means (17) to illuminate the marked object through a low pass filter (18) and means (20) to detect radiation emanating from the object through a high pass filter (19).