# US 10,245,867 B2 · Thermal imaging

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- Number: US 10,245,867 B2
- Document ID: US10245867B2
- Status: Granted
- Kind: B2
- Application number: 13/921,130
- Filed: 2013-06-18
- Published: 2014-12-18
- Granted: 2019-04-02
- Earliest claimed: 2013-06-18
- Applicants: John C. Warner
- Inventors: John C. Warner
- Web page: https://patentgrep.com/patent/US10245867B2

## CPC

- B41M 5/323: Organic colour formers, e.g. leuco dyes
- B41M 5/333: Colour developing components therefor, e.g. acidic compounds
- B41M 5/3372: {Macromolecular compounds}
- B41M: PRINTING, DUPLICATING, MARKING, OR COPYING PROCESSES; COLOUR PRINTING, (correction of typographical errors B41J; processes for applying transfer pictures or the like B44C1/16; fluid media for correction of typographical errors by coating C09D10/00; printing textiles D06P)

## Abstract

Disclosed and claimed herein is a thermosensitive recording medium, having a base sheet; a binder; and a thermosensitive material on at least one surface of the base sheet comprising: one or more oxidizing agents; and a dye precursor.

## Claims

### Claim 1

A thermosensitive recording medium comprising:
a. a base sheet;
b. a thermosensitive composition on at least one surface of the base sheet comprising a binder and a thermosensitive material comprising:
i. one or more oxidizing agents; and
ii. a dye precursor having the formula;
wherein R1 and R2 can be the same or different and are: H, alkyl of 1-4 C, NH2, OH, COOR′ wherein R′ is alkyl of 1-4C or H, CONH2, halogen, OR″ wherein R″ is alkyl of 1-4C, CH2 OH, CH2NH2, CONR′R″ wherein R′ and R″ can be the same or different; R3 is H or alkyl of 1-4C or COR″; R4, R5 can be the same or different and are: H, alkyl of 1-4C, NH2, OH, COOH, CONH2, halogen, OR″, NO2, SO3, HNR″, or NR″R″ or any pharmaceutically acceptable salts thereof or mixtures thereof, and wherein R6 and R7 can be the same or different and can be hydrogen, a carboxylate group, a borate group or a silicate group.

### Claim 2 (depends on 1)

The thermosensitive recording medium of claim 1, wherein the binder comprises a resin chosen from polystyrene, polyvinyl alcohol, polyvinyl pyrrolidone, polyacrylamide, polymethacrylamide, polyacrylic acid, polymethacrylic acid, polyethylene glycol, proteinaceous binders, gelatin, modified gelatins, phthaloyl gelatine, polysaccharides, starch, gum arabic and dextran, water-soluble cellulose, resin having an ether bond, resin having a carbamoyl group, resin having a carboxyl group, derivatives or combinations thereof.

### Claim 3 (depends on 1)

The thermosensitive recording medium of claim 1, further comprising sodium bicarbonate, potassium bicarbonate, microencapsulated sodium bicarbonate or microencapsulated potassium bicarbonate.

### Claim 4 (depends on 1)

The thermosensitive recording medium of claim 1, wherein the dye precursor is chosen from L-DOPA, R-DOPA or pharmaceutically acceptable salts thereof or mixtures thereof.

### Claim 5 (depends on 1)

The thermosensitive recording medium of claim 1, wherein R1 and R2 are non hydrogen substituents and the dye precursor comprises two or more diastereomers.

### Claim 6 (depends on 1)

The thermosensitive recording medium of claim 1, wherein the oxidizing agent is a pharmaceutically acceptable salt whose anion is chosen from peroxide, periodate, persulfate, perborate, iodate peroxydisulfate, monopersulfate, or hypochlorite.

### Claim 7 (depends on 1)

The thermosensitive recording medium of claim 1, wherein the oxidizing agent is chosen from sodium periodate, potassium periodate, ammonium periodate or mixtures thereof.

### Claim 8 (depends on 1)

The thermosensitive recording medium of claim 1, further comprising one or more pharmaceutically acceptable carbonate salts.

### Claim 9 (depends on 1)

The thermosensitive recording medium of claim 1, wherein the oxidizing agent is a metal salt.

### Claim 10 (depends on 1)

The thermosensitive recording medium of claim 1, wherein the oxidizing agent is a transition metal salt.

### Claim 11 (depends on 1)

The thermosensitive recording medium of claim 1, wherein the oxidizing agent is a metal salt chosen from copper, titanium, zinc, iron, nickel, cobalt, lead, silver and manganese.

### Claim 12 (depends on 1)

The thermosensitive recording medium of claim 1, wherein the thermosensitive recording medium is substantially free of organic base.

### Claim 13 (depends on 1)

The thermosensitive recording medium of claim 1, wherein the mole ratio of the oxidizing agent to the dye precursor is greater than about 0.05 and less than about 2.0.

### Claim 14 (depends on 1)

The thermosensitive recording medium of claim 1, further comprising an ester capable of retarding the oxidation of the dye precursor.

### Claim 15 (depends on 14)

The thermosensitive recording medium of claim 14, wherein the ester is a borate or a silicate.

### Claim 16 (depends on 1)

The thermosensitive recording medium of claim 1, wherein at least some of the one or more oxidizing agents are microencapsulated.

### Claim 17 (depends on 1)

The thermosensitive recording medium of claim 1, wherein the dye precursor is microencapsulated.