JPS60259497A - Thermal transfer system - Google Patents

Abstract

PURPOSE:To form high-quality pictures on usual papers by effectively utilizing the same transfer sheet by a method in which a transfer sheet is moved always relatively to a thermal head during the recording period while specifying its moving speed within a specific range. CONSTITUTION:A transfer sheet consisting of a leuco dye layer and a developer layer which are laminated in an optional order, having a transfer layer in which the lower layer is meltable at higher temperatures than the upper layer, is lapped on an usual paper in such a way as to contact the usual paper with the transfer layer of the transfer sheet. Thermal transfer operation is then made while pressingly contacting the transfer sheet with a thermal head to generate a thermal pattern according to desired recording information to obtain a color picture on the usual paper. In this case, the transfer sheet is moved in a ratio of 1/ N more or less of the length of picture point per recording of one picture point (where N is the number of specified repetitive using times of the transfer sheet). When thermal transfer operation is made by using a thermal transfer type printer, transfer onto usual papers can be effectively attained.

Description

Detailed Description of the Invention [Technical Field] The present invention uses plain paper and a transfer sheet having a transfer layer containing a leuco dye and a color developer, and uses a small amount of thermal energy to transfer a high-density transferred image onto the plain paper. The present invention relates to a thermal transfer method capable of obtaining a transferred image with uniform image density in multiple transfers using the same transfer sheet.

[Prior art] Conventionally, thermal transfer media include those consisting of a transfer sheet in which a heat-sublimable dye is provided on a support and a receiving sheet that receives a heat-sublimable dye image by thermal printing from the back side of the sheet; A combination of a transfer sheet and a receiving sheet is known, in which a transfer layer of a fusible substance and a pigment or dye is provided on a support.The former uses a heat sublimable dye, so the dye image on the receiving sheet is It has poor storage stability and requires an overcoat to be applied over the transferred image, and the latter is a transfer layer with pigment or dye dispersed in a thermofusible substance, so it is difficult to obtain a high-density image. If a large amount of pigment is included, the transfer efficiency will be lowered, making it difficult to obtain a high-density image. Because the fusible substance migrates to the receiving sheet side, when the transfer sheet and receiving sheet are peeled off, the separation does not occur smoothly, and the image area of fine lines becomes unclear.
In addition, since the transfer sheet is colored,
There is a drawback that if the paper is strongly pressed against the receiving sheet, coloration occurs even in non-image areas.

The present inventors have previously proposed various thermal transfer media that have improved the above-mentioned drawbacks. In such a thermal transfer medium, a large number of copies can be obtained by using the same transfer sheet and performing thermal transfer by replacing the receiving sheet one after another. Further, this thermal transfer can be performed using a thermal transfer type printer having a thermal head while moving the transfer sheet relative to the thermal head. However, in this case, it was necessary to use a special sheet having a color developer layer as the receiving sheet, and transfer onto Toyonaka paper was impossible.

・, 7 [Purpose] The present invention aims to provide a thermal transfer method that can efficiently transfer onto plain paper when performing thermal transfer using a thermal transfer printer.

[Structure] According to the present invention, there is provided a transfer sheet having a transfer layer consisting of a leuco dye layer and a color developer layer laminated in an arbitrary order, the lower layer being meltable at a higher temperature than the upper layer, and plain paper. are placed on top of the plain paper so that the transfer layer surface of the transfer sheet is in contact with the plain paper, and thermal transfer is performed while the transfer sheet is pressed against a thermal head that generates a thermal pattern according to the desired recording information, and the transfer sheet is transferred onto the plain paper. The transfer sheet is applied to the thermal head at a rate of 1/N or more of the length of the pixel (N is the specified number of times the transfer sheet is repeatedly used) and A thermal transfer method is provided which is characterized by moving at a rate less than the dot length.

The method of the present invention can be carried out using a thermal transfer printer.In this case, this thermal transfer L-type printer includes a thermal head that generates a thermal pattern according to recorded information, and a thermal head that generates a thermal pattern according to recorded information. A feeding mechanism is provided to move the transfer sheet at a required speed. That is, in such a thermal transfer printer, for example, like a thermal transfer typewriter, the transfer sheet moves relative to the thermal head each time a pixel is recorded. In the conventional case, the transfer sheet moved at a high speed of at least the length of one pixel per pixel recorded, so although the transferred image was clear, the transfer sheet was rapidly worn out. Moreover, when it is attempted to use the transfer sheet many times, it takes time and effort to rewind the transfer sheet to its original state, which is not efficient. In the case of the present invention, the moving speed of the transfer sheet relative to the thermal head is - per pixel recording;
1/N of the pixel length (N is the specified number of times of repeated use of the transfer sheet) or more and less than the pixel length, preferably 1/N of the pixel length
/N, which prevents the transfer sheet from being worn out and saves the effort of rewinding the transfer sheet. The transfer sheet used in the present invention is made by laminating a leuco dye layer containing a leuco dye as a main component and a color developer layer containing a color developer as a main component on the surface of a support such as paper, synthetic paper, or plastic film. It is something that In this case, the lamination order of the leuco dye layer and the color developer layer is arbitrary, and the leuco dye layer may form the upper layer or the color developer layer may form the upper layer, but the present invention In this case, the color developer layer or leuco dye layer forming the lower layer has a higher temperature melting property than the leuco dye layer or color developer layer forming the upper layer. When the transfer layer has such a laminated structure,
When thermal transfer is performed, the low-temperature melting upper layer is transferred to plain paper, and then the high-temperature melting lower layer has its melting point lowered by contact with the upper layer melt, and is melt-transferred onto the plain paper. A reactive colored image is formed. In the case of the present invention, since the transfer layer has the above-described layer structure, the transfer layer is not transferred to plain paper all at once, and a transfer sheet that can be used repeatedly can be obtained. Since the transfer layer used in the present invention is usually colorless or light-colored, no image is formed even if it is strongly pressed against plain paper, and therefore no stains occur in non-image areas. That is, the present invention is characterized in that a colored image becomes clear.

As the leuco dye used in the present invention, any dye conventionally used for pressure-sensitive paper or thermal paper can be used, including triphenylmethane-based dyes.

Fluorane-based, phenothiazine-based, auramine-based, and spiropyran-based materials are preferably used. Specific examples of these leuco dyes are shown below.

3.3-Bis(P-dimethylaminophenyl)-phthalide.

3.3-bis(p-dimethylaminophenyl)-6=dimethylaminophthalide (also known as crystal violet lactone).

3.3-bis(p-dimethylaminophenyl)-6=diethylaminophthalide, 3.3-bis(P-dimethylaminophenyl)-6-chlorophthalide, 3.3-bis(P-dibutylaminophenyl)phthalide, +1 '1 [3-cyclohexylamino-6-chlorofluorane, 3-dimethylamino-5,7-dimethylfluorane, 3
-diethylamino-7-lyrolofluorane, 3-diethylamino-7-methylfluorane, 3-diethylamino-7,8-benzfluorane, 3-diethylamino-6
-Methyl-7-chlorofluorane, 3-(N-ρ-toly-N-ethylamino)-6-methyl-7-anilinofluorane, 3-pyrrolidino-6-methyl-7-anilinofluorane, 2 - (N-(3'-)-lifluoromethylphenyl)amino)-6-dinithylaminofluorane, 2-(3
, 6-bis(diethylamino)-9-(o-chloroanilino)xantylbenzoic acid lactam), 3-diethylamino-6-methyl-7-(m-trichloromethylanilino)fluoran, 3-diethylamino-7-(0- chloranilino) fluorane, 3-dibutylamino-7-(o-chloroanilino) 1
fluorane, 3-N-methyl-N-amylamino-6-methyl-7-
Anilinofluorane.

3-N-methyl-N-cyclohexylamino-6-methyl-7-anilinofluorane, 3-diethylamino-6-methyl-7-anilinofluorane, 3-(N,N-diethylamino)-5- Methyl-7-(
N.

N-dibenzylamino)fluoran, benzoylleucomethylene blue, 6'-chloro-8'-methoxy-benzoindolino-pyrylospirane, 6'-bromo-3'-methoxy-benzoindolino-pyrylosvirane, 3-(2'- Hydroxy-4'-dimethylaminophenyl)-3-(2'-methoxy-5'-chlorophenyl)phthalide, 3-(2'-hydroxy-47-dimethylaminophenyl)-3-(2'-methoxy-5 '-nitrophenyl)phthalide, 3-(2'-hydroxy-4'-diethylaminophenyl)-3-(2'-methoxy-5'-methylphenyl)phthalide, 3-(2'-methoxy-4'- dimethylaminophenyl)-3-(2'-hydroxy-4'-chloro-5'
-methylphenyl)phthalide, 3-morpholino-7-(N-propyl-trifluoromethylanilino)fluorane, 3-pyrrolidino-7-trifluoromethylanilinofluorane, 3-diethylamino-5-chloro-7-( N-benzyl-trifluoromethylanilino)fluorane.

3-pyrrolidino-7-(di-P-chlorophenyl)methylaminofluorane, 3-diethylamino-5-chloro-7-(α-phenylethylamino)fluoran, 3-(N-ethyl-p-toluidino)-7 -(α-phenylethylamino)fluoran, 3-diethylamino-7-(o-methoxycarbonylphenylamino)fluoran, 3-diethylamino-5-methyl-7-(α-phenylethylamino)fluoran, 3-diethylamino-7 -piperidinofluorane, 2-
Chloro-3-(N-methyltoluidino)-7-(p-n
-butylanilino)fluorane, 3-(N-benzyl-N-cyclohexylamino)-5
, 6-penzo 7-α-naphthylamino-4'-bromofluorane, 3-diethylamino-6-methyl-7-mesitidino 4
',5'-benzofluorane, 3.6-simethoxyfluorane, 3-(P-dimethylaminophenyl)-3-phenylphthalide, 3-di(1-ethyl-2-methylyldol)-3 -yl-phthalide, 3-diethylamino-6-phenyl-7-azafluorane, 3.3-bis(P-diethylaminophenyl)-6-dimethylaminophthalide 1, f2-bix(p-dimethylaminophenyl) Methyl-
5-dimethylamino-benzoic acid.

3-(p-dimethylaminophenyl)-3-(p-dibenzylaminophenyl) phthalide and the like.

Further, examples of the color developer used in the present invention include the following.

4-tert nibutylphenol, 4-hydroxydiphenyl ether, 1-naphthol, 2-naphthol,
Methyl-4-hydroxybenzoate, 4-hydroxyacetophenone, 2,2'-dihydroxydiphenyl ether, 4-phenylphenol, 4-tert,
-octylcatechol, 2,2'-dihydroxydiphenyl, 4,4'-methylenebisphenol, 2.2
' -methylenebis(4-chlorophenol), 2.2
'-methylenebis(4-methyl-6-tert-butylphenol), 4,4'-isopropylidenediphenol, 4,4'-isopropylidenebis(2-chlorophenol), 4,4'-isopropylidenebis(
2゜6-dibromophenol), 4,4'-isopropylidene bis(2-tert-butylphenol), 4
, 4'-isopropylidene bis(2-methylphenol), 4. 14'-isopropylidene bis(2,6
-dimethylphenol), 4.4'-5ac-butylidene diphenol, 4.4'-5ec-butylidene bis(2-methylphenol), 4.4'-cyclohexylidene diphenol, 4.4'-cyclohexylidene bis (2-methylphenol), salicylic acid, salicylic acid methalyl ester, salicylic acid phenacyl ester, 4-hydroxybenzoic acid methyl ester, 4-hydroxybenzoic acid ethyl ester, 4-hydroxybenzoic acid isopropyl ester, 4-hydroxybenzoic acid butyl ester , 4-hydroxybenzoic acid isoamyl ester, 4-hydroxybenzoic acid phenyl ester, 4-hydroxybenzoic acid benzyl ester, 4-hydroxybenzoic acid cyclohexyl ester, 5-hydroxysalicylic acid, 5-chlorsalicylic acid, 3-chlorsalicylic acid,
Thiosalicylic acid, 2-chloro-5-nitrobenzoic acid, 4
-methoxyphenol, 2-hydroxybenzyl alcohol, 2,5-dimethylphenol, benzoic acid, orthotoluic acid, metatoluic acid, paratoluic acid, orthochlorobenzoic acid, metaoxybenzoic acid, 2,4-dihydroxyacetophenone), resorcinol monobenzoate, 4-hydroxybenzophenone, 2.4-dihydroxybenzophenone, 2-naphthoic acid, 1-hydroxy-2-naphtoic acid, 3,
4-dihydroxybenzoic acid ethyl ester, 3,4-dihydroxybenzoic acid phenyl esterphenone, salicyl salicylate, phthalic acid monobenzyl ester, 1,1-bis(4'-hydroxyphenyl)methane.

■,1-bis(4'-hydroxyphenyl)ethane.

1,1-bis(4'-hydroxyphenyl)propane.

■,1-bis(4'-hydroxyphenyl)hexane, 1,1-bis(4'-hydroxyphenyl)hebutane, 1,1-bis(4'-hydroxyphenyl)-2
-propylpentane, 1,1-bis(4'-hydroxyphenyl)-2-ethylhexane, 2,2-bis(4'-hydroxyphenyl)propane, 2,2-bis(4'-hydroxyphenyl)hexane, 2.2-bis(4'-hydroxyphenyl)hebutane, 3,3-bis(4'-hydroxyphenyl)hexane, 1.1-bis(3'-methyl-4'-hydroxyphenyl)ethane.

], 1-bis(3'-methyl-41-hydroxyphenyl)propane, l, ■-bis(3'-methyl-4'-hydroxyphenyl)butane, 1.1-bis(3'-methyl-47- hydroxyphenyl)pentane, 1.1-bis(3'-methyl-4'-bitroxyphenyl)hexane, 1-bis(3'-methyl-4'-hydroxyphenyl)hebutane, 2-(3'-methyl-4'-hydroxyphenyl)-
2-(4'-Hydroxyphenyl)propane.

2.2-bis(3'-methyl-4'-hydroxyphenyl)pentane, 2.2-bis(5'-methyl-4'-hydroxyphenyl)hexane, 2.2-bis(3') -Methyl-4'-hydroxyphenyl)4-methylpentane, 1.1-bis(3'-methyl-4'-hydroxyphenyl)4-methylbutane, 3.3-bis(3'-methyl-4'-hydroxy phenyl)pentane, 3.3-bis(3'-methyl-4'-hydroxyphenyl)hexane, 5.5-bis(3'-methyl-4'-hydroxyphenyl)nonane, 2-(4'-hydroxyphenyl) )-2-(3'-
Chlor-4'-hydroxyphenyl)propane, 2.2
-bis(3'-isopropyl-4'-hydroxyphenyl)propane, 2.2-bis(3'-tert-butyl-4'-hydroxyphenyl)propane, 2.2-bis(3'-chloro-4') 2-(4'-hydroxy-3',5'-dimethylphenyl)-2-(4'-hydroxyphenyl)furopane.

Bis(3'-methyl-5'-ethyl-4'-hydroxyphenyl)methane, 1.1-(3'-methyl-5'-butyl-4'-hydroxyphenyl)butane, 2.2-bis(4 -hydroxyphenyl)octane, bis(4-hydroxyphenylmercapto)methane, ■, 2-bis(4-hydroxyphenylmercapto)ethane, 1.3-bis(4-hydroxyphenylmercapto)propane, ■, 4-bis( 4-hydroxyphenylmercapto)butane, 1,5-bis(4-hydroxyphenylmercapto)pentane, ■, xane containing 6-bis(4-hydroxyphenylmercapto), ■, 3-bis(4-hydroxyphenylmercaptoacetone), 1,5-bis(4-hydroxyphenylmercapto)3
-oxapentane, ■,7-bis(4-hydroxyphenylmercapto)3
, 5-dixahebutane, 1,8-bis(4-hydroxyphenylmercapto)3
, 5-dioxaoctane.

Further, in the present invention, if necessary, a thermofusible substance having a melting point of 200°C or less, preferably 150°C or less is added to the leuco dye layer and/or color developer layer constituting the transfer layer. It can be added. Examples of thermofusible substances in this case include conventionally known fatty acid amides, aromatic carboxylic acid amides, amides of fatty acids and aromatic carboxylic acids having a cyclohexyl ring, and alkyl or aryl esters of aromatic carboxylic acids. Examples include: The amount of the thermofusible substance used is 0.1 to 50 parts by weight per 1 part by weight of the leuco dye. Specific examples of this thermofusible substance include the following.

Laurylic acid amide, caproic acid amide, palmitic acid amide, stearic acid amide, behenic acid amide, N-methyl stearic acid amide, N-cyclohexyl stearic acid amide, N-lauryl benzamide, N-stearylbenzamide, N-stearylacetamide, etc. Amides, 4-hydroxybenzoic acid phenyl ester, 4-hydroxybenzoic acid 2-methoxyphenyl ester, salicylic acid 2-methoxyphenyl ester, benzoic acid
4-benzylphenyl ester, benzoic acid-4-methoxyphenyl ester, 4-benzoyloxybenzoic acid methyl ester, 4-benzoyloxybenzoic acid phenyl ester, benzoic acid-4-cyanophenyl ester, etc.

When a transfer layer is provided on a support, a resin is preferably used as the binder, and in the present invention, it is preferable to use a resin having a melting point or softening point of 50 to 130°C. In this case, the resin can be either thermoplastic or thermosetting. Specific examples of such resins include:

1' month). □7. , 0.6 polyethylene, polypropylene, polystyrene 4 petroleum resin, acrylic resin, vinyl chloride resin, vinyl acetate resin,
Vinylidene chloride resin, polyvinyl alcohol 4 cellulose 41 fat, polyamide, polyacetal, polycarbonate, polyester, fluorine ms, silicone resin, natural rubber, chloride rubber, butadiene rubber, olefin rubber, phenolic resin, urea! 111m, melamine resin, epoxy resin, polyimide, etc.

The above-mentioned resins can be used in the form of a single polymer.

It can be used in the form of a copolymer or a mixture of multiple resins. The amount of this resin used is leuco dye and color developer 1
It is used in a range of +O,OX to 1 part by weight. When this amount of resin is less than 0.01 parts by weight,
The adhesion to the transfer sheet weakens, making it impossible to support the leuco dye and color developer on the support with sufficient adhesion.On the other hand, if the amount exceeds 1 part by weight, the thermal sensitivity of the product decreases. This decreases the density of the resulting transferred image.

The amount of resin is 1 (0.05 to 0.0% per 1 part by weight of leuco dye and color developer).
It is preferable to use 5 parts by weight in order to obtain uniform image density in multiple transfers. The method and method for applying the resin to the support include solvent coating, hot melt coating,
Either aqueous emulsion coating may be used.

Further, in the present invention, a porous filler can also be included in the transfer layer. In this case, the porous filler should have an oil absorption of at least 5 (1 mQ/] OOg (according to JIS K 5101 method) - preferably 15 axial a/100 g or more6. If the transfer sheet is moved at a reduced speed.

Use of a large amount of porous filler reduces the clarity of the transferred image and reduces the number of times N of repeated use of the transfer sheet.

The proportion of porous filler used is 0.01 to 1 part by weight, preferably 0.03 to 1 part by weight, per 1 part by weight of leuco dye or color developer.
It is 0.5 part by weight. Specific examples of the porous filler used in the present invention are as follows: 1. For example, inorganic acid and organic fine powders such as silica, aluminum silicate, alumina, aluminum hydroxide, magnesium hydroxide, urea-photo marine resin, styrene resin, etc. can be mentioned.

〔effect〕

In the case of the present invention, the transfer sheet is
Since the transfer sheet is always moved relatively during recording, the moving speed of the transfer sheet is specified within a specific range, making it possible to effectively use the same transfer sheet to obtain high-quality images on plain paper. Furthermore, in the present invention, a desired recorded image is formed by transferring a transfer layer containing a usually colorless or light-colored leuco dye and a color developer onto plain paper, so it is not necessary to use conventional hot-melt colored inks. There is no staining of the non-image area due to pressure contact as seen.

(Example) Next, the present invention will be explained in more detail with reference to Examples. Note that all parts and percentages shown below are based on weight.

Example 1 (1) Formation of high temperature melting leuco dye layer (lower layer) 3-N-
Methyl-N-cyclohexylamino-6-methyl-7-
A composition consisting of 10 parts of anilinofluorane and 1 part of polyester repellent was dissolved in 100 parts of methyl ethyl ketone, applied to the surface of a 6 μm thick polyester film using a wire bar, and dried to adhere; 5 parts, 3 g/polymer. A high temperature melting leuco dye layer was formed.

(2) Formation of low-temperature melting color developer layer (upper layer) A composition consisting of 20 parts of 4-hydroxybenzoic acid n-butyl ester, 3 parts of polyvinyl alcohol, and 100 parts of water was dispersed for 24 hours using a ball mill, and then dispersed using a wire bar. was applied to the lower layer and dried to form a low-temperature melting color developer layer with a coating weight of 7 g/rrl'.

Next, a thermal transfer test was conducted using the transfer sheet obtained as described above. In this case, as the thermal transfer device, a thermal transfer printer for a tie H+j) plater having a thermal head was used. This device is equipped with a transfer sheet feeding mechanism for moving the transfer sheet (transfer ribbon), and can adjust the moving speed of the transfer sheet relative to the thermal head.

In the thermal transfer test described above, the specified number of times N of repeated use of the transfer sheet was set to 10, and the relative moving speed of the transfer sheet with respect to the thermal head was adjusted to a ratio of 1/100 of the pixel length. Further, the heating energy applied to the thermal head was adjusted to 1.5 mJ.

When the quality of the colored image on plain paper obtained as described above was examined, a clear black image with an image density of 1.25 was obtained. Note that no stains were observed in the non-image areas on the plain paper.

Example 2 (1) Formation of high temperature melting leuco dye layer (lower layer) Composition consisting of 15 parts of ristal violet lactone, 1 part of silica fine particles (oil absorption: 300 m Q /100 g), 1 part of vinyl chloride vinyl acetate copolymer, 2 parts of 100 parts of methyl ethyl ketone Disperse the substance for 24 hours using a ball mill I
Thereafter, using a wire bar, it was coated on the surface of a 6 μm thick polyester film and dried to form a lower layer with a coating weight of 3 g/i.

(2) Formation of low-temperature melting color developer layer (upper jF7) 1.5-
After dispersing a composition consisting of 100 parts of bis(4-hydroxyphenylmercapto silica particles, 2 parts of methyl cellulose, 2 parts of water) for 24 hours using a ball mill,
Using a wire bar, it was coated on top of the lower layer and dried to form an upper layer with a coating weight of 7 g/m.

Next, a thermal transfer test was conducted in the same manner as in Example 1, and a high-quality copy with a clear blue image with an image density of 1.20 and no stains in the non-image area was obtained. It was confirmed that the thermal transfer method of the invention can be fully put to practical use.

Patent applicant Rico Co., Ltd. Representative Patent Attorney Toshiaki Ikeura

Claims (1)

[Claims] (1) Transferring a transfer sheet consisting of a leuco dye layer and a color developer layer laminated in an arbitrary order, and having a transfer layer in which the lower layer has a higher melting temperature than the upper layer, and plain paper, Layering the layer surface and plain paper so that they are in contact with each other, and performing thermal transfer while pressing the transfer sheet against a thermal head that generates a thermal pattern according to the desired recording information,
It consists of forming a colored image on plain paper, and the transfer sheet is placed against a thermal head,
A thermal transfer method characterized in that the pixel is moved at a rate of 1/N of the length of the pixel (N is the specified number of times of repeated use of the transfer sheet) or more and less than the length of the pixel.