# US 5,332,459 A · Thermal transfer printing method using intermediate sheets

> Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt

- Number: US 5,332,459 A
- Document ID: US5332459A
- Status: Granted
- Kind: A
- Application number: 07/725,669
- Filed: 1991-07-03
- Granted: 1994-07-26
- Earliest claimed: 1990-07-04
- Assignees: Matsushita Electric Industrial Co., Ltd.
- Inventors: Akihiro Imai; Yasuo Fukui; Nobuyoshi Taguchi
- Web page: https://patentgrep.com/patent/US5332459A

## CPC

- B41M 5/38257: {characterised by the use of an intermediate receptor}
- B41M 5/5254: {characterised by the use of polymers obtained by reactions only involving carbon-to-carbon unsaturated bonds, e.g. vinyl polymers}
- 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

The present invention is directed to a thermal transfer printing process comprising: heating a thermal ink film with a printing head to print dye transferring images onto an intermediate sheet which comprises a substrate and a printing layer thereon, heaping an image receive sheet on said printing layer, and transferring said printing layer onto an image receive sheet by pressure or heat; The improvement residing in that said printing layer is formed from polyvinyl acetal. The present invention also provides an intermediate sheet for the above thermal transfer printing process comprising a substrate and a printing layer on said substrate wherein said printing layer is formed from polyvinyl acetal.

## Claims

### Claim 1

A thermal transfer printing process comprising:
heating a thermal ink film with a printing head to print dye transferring images onto an intermediate sheet which comprises a substrate and a printing layer thereon,
heaping an image receive sheet on said printing layer, and
transferring said printing layer onto said image receive sheet by pressure or heat;
wherein said thermal ink film comprises a substrate and a color layer comprising:
a dye, and
a polymer binder which is selected from the group consisting of acrylonitrile-styrene copolymer, polystyrene, styrene-acryl copolymer, polyvinyl chloride, chlorinated polyvinyl chloride, polyvinyl acetate, vinyl chloride-vinyl acetate copolymer, vinyl chloride-acrylic ester copolymer, saturated polyester, polyester urethane, cellulose resin, rubber chloride, chlorinated polypropylene, polycarbonate and a mixture thereof, and wherein said printing layer is formed from polyvinyl acetal, and either said color layer or said printing layer or both contain a fluorine or siloxane-containing moisture curable resin.

### Claim 2 (depends on 1)

The thermal transfer printing process according to claim 1 wherein said polyvinyl acetal is selected from the group consisting of polyvinyl formal, acetoacetalized polyvinyl alcohol and propionacetalized polyvinyl alcohol.

### Claim 3 (depends on 1)

The thermal transfer printing process according to claim 1 wherein said printing head is a thermal head.

### Claim 4 (depends on 1)

The thermal transfer printing process according to claim 1 wherein said polyvinyl acetal has an acetalization degree of 50 mol % or more.

### Claim 5 (depends on 1)

The thermal transfer printing process according to claim 1 wherein said polyvinyl acetal has a flow softening point of 80.degree. to 250.degree. C.

### Claim 6 (depends on 1)

The thermal transfer printing process according to claim 1 wherein said fluorine-containing moisture curable resin is a fluorine-containing acrylsilicon resin.

### Claim 7 (depends on 1)

The thermal transfer printing process according to claim 1 wherein said siloxane-containing moisture curable resin is a siloxane-containing acrylsilicon resin.