# US 4,396,684 A · Heat-sensitive recording paper causing reduced thermal head abrasion

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- Number: US 4,396,684 A
- Document ID: US4396684A
- Status: Granted
- Kind: A
- Application number: 06/298,515
- Filed: 1981-09-01
- Granted: 1983-08-02
- Earliest claimed: 1979-07-20
- Assignees: Mitsubishi Paper Mills Limited
- Inventors: Sadao Morishita; Fumio Okumura; Masahiro Higuchi; Syun Kamei
- Web page: https://patentgrep.com/patent/US4396684A

## CPC

- B41M 5/30: using chemical colour formers (B41M5/34 takes precedence)
- Y10S 428/913: Material designed to be responsive to temperature, light, moisture
- 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)
- Y10S: TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS

## Abstract

In the heat-sensitive recording paper produced by coating a support such as paper or the like with a coating solution containing a normally colorless or light-colored dye precursor and a developer capable of making the precursor develop color upon heating, the abrasion of a thermal head can be decreased by adjusting the total amount of sodium and potassium ions in the coating on the heat-sensitive recording paper to 1,051 ppm or less, preferably 500 ppm or less, most preferably 400 ppm or less.

## Claims

### Claim 1

A heat-sensitive recording paper composed of
a paper, and
a coating formed by applying to the surface of the paper a coating solution containing constituents parts which comprise
a colorless or light-colored dye precursor and a developer capable of making the dye develop color upon heating, an organic or inorganic powder, a binder, a sensitizer, a dispersant, and industrial water,
wherein the total amount of sodium and potassium ions in the coating is controlled to 601 ppm or less by excluding the use of sodium and/or potassium-containing compounds as the organic or inorganic powder, the binder, and the dispersant, and removing sodium and/or potassium as impurities contained in the organic or inorganic powder, the binder, the dispersant, and the industrial water.

### Claim 2 (depends on 1)

A heat-sensitive recording paper according to claim 1, wherein the total amount of sodium ions and potassium ions in the coating is 500 ppm or less.

### Claim 3 (depends on 1)

A heat-sensitive recording paper according to claim 1, wherein the total amount of sodium ions and potassium ions in the coating is 400 ppm or less.