JPS5935984A - Thermal transfer medium - Google Patents

Abstract

PURPOSE:To enable high-density transfer images to be obtained repeatedly, by adjusting the surface smoothness level within a specified range in a transfer layer mainly composed of a leuco dye and/or a receiving layer mainly composed of a color developer for the leuco dye. CONSTITUTION:A transfer layer mainly composed of a leuco dye such as crystal violet lactone is provided on a support such as paper or plastic film to form a transfer sheet. A receiving layer mainly composed of a color developer (e.g. 4-tert-butylphenol or 2-naphthol) for the leuco dye is provided on a support such as paper or plastic film to form a receiving sheet. The surface smoothness (Beckmann smoothness) of the transfer layer and/or the receiving layer is adjusted to 200-1,000sec by calendering or the like and the transfer sheet and the receiving sheet thus obtained are combined together to make an intended thermal transfer medium.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a thermal transfer medium on which a high-density image can be obtained and which can be transferred many times.

Conventionally, thermal transfer media include those consisting of a transfer sheet with a heat-sublimable dye layer provided on a support and a receiving sheet that receives a sublimable dye image by thermal printing from the back side of the sheet, or a heat-fusible material. A combination of a transfer sheet with a pigment or dye transfer layer on a support and a receptor sheet is known.
The former method uses heat-sublimable dyes, resulting in poor preservation of the dye image on the receiving sheet and requires an overcoat on the transferred image, and the latter method uses heat-fusible materials. Since the transfer layer has pigments or dyes dispersed in it, if a large amount of pigment is included in order to obtain a high-density image, the transfer efficiency will be lowered, and as a result, it will be difficult to obtain a high-density image. If a large amount of thermofusible material is used to increase the transfer rate, a large amount of the thermofusible material will migrate to the receiving sheet side, so when separating the transfer sheet and receiving sheet,
There were drawbacks such as not peeling off smoothly and image areas of fine lines becoming unclear.

On the other hand, there is also known a thermal transfer medium in which substances that react with each other to form a color due to heat are supported on separate supports, and these support layers are brought into mutually facing contact to perform thermal printing.
This kind of thing is reactive, so when you come into contact with it face-to-face,
If the transfer layer simply transfers to the receiving layer, a sufficient color reaction will not take place, resulting in a low-density image. If this is the case, the received image will have a higher density image, but there is a drawback that the coloring reaction will proceed even on the transfer sheet and image formation will occur.

The present invention (d) provides a thermal transfer medium that has higher thermal sensitivity and can produce high-density images compared to the above-mentioned divine thermal transfer media, and also provides a thermal transfer medium that can produce images with higher thermal sensitivity and higher density by transferring a small amount of dye components from the transfer layer to the receiving layer. The purpose of the present invention is to provide a thermal transfer medium on which high-density transferred images can be transferred many times.

That is, in the present invention, 1 = so to speak, a transfer sheet having a transfer layer containing leuco-dyed dye as a main component, and a receiving note having a receiving layer containing a color developer for the leuco dye as a main component; , the transfer layer and/or the receptor layer have a surface smoothness (
Provided is a thermal transfer medium having a Beckman smoothness of 200 to 1000 seconds.

In the thermal transfer medium of the present invention, a receiving sheet is stacked on a transfer sheet so that its receiving layer is in contact with the transfer layer of the transfer sheet, and a desired image is printed on the surface of the receiving sheet by thermal printing from the back side of the transfer sheet or the back side of the receiving sheet. However, in the present invention, the surface smoothness of the transfer layer and/or receiving layer is adjusted to 200 to 1000 seconds, so thermal sensitivity is improved and transfer efficiency is improved. This allows efficient transfer of multiple sheets.

Note that the surface smoothness referred to in this specification is Beckman smoothness (
J15-1)8 ] 19). The surface smoothness of the transfer layer and the receiving layer can be adjusted by a conventional method such as calendering.

The transfer sheet used in the present invention is one in which a transfer layer containing a leuco dye as a main component is provided on a support such as paper, synthetic paper, or plastic film. As the leuco dye in this case, any dye conventionally used for pressure-sensitive paper or thermal paper can be used, and triphenylmethane-based, fluoran-based, phenothiazine-based, auramine-based, and spiropyran-based ones are preferred. Applicable properly. Specific examples of these leuco dyes are shown below.

3.3-bis(p-dimethylaminophenyl)-phtali 1- 3.3-bis(p-dimethylaminophenyl)-(i
*□-dimethylaminophthalide (also known as crystalviolenol-lactone) 3,3-bis(p-dimethylaminophenyl)-〇-
Diethylaminophthalide 3.3-bis(p-dimethylaminophenyl)-G-chlorphthalide 3.3-bis(p-dibutylaminophenyl)phthalide 3-cyclohequinylamino-6-chlorofluoran 3-(N,N- diethylamino)-5-methyl-y-(
N,N-dibenzylamino)fluoran 3-dimethylamino-5,7-cyphthylfluoran: (-diethylamino-7-methylfluoran: (-diethylamine-7,8-benzfluoran 5- 3-diethylamino- 6-Methyl-7-chlorofluoran 3-pyrrolidino-6-methyl-7-anilinofluoran 2-(N-(3'-t-IJ fluoromethylphenyl)amine)-6-dinithylaminofluoran 2-(3,
6-bis(diethylamino)-9-(0-chloroanilino)xantylbenzoic acid lactam) 3-diethylamino-7-(0-chloroanilino)fluoran 3-cyphthylamino-7-(0-chloroanilino)fluoran 3-N-methyl-N -amylamino-6-methyl-7-
Anilinofluoran 3-N-Methyl-N-cyclohexylamino-6-methyl-7-anilinofluoran 3-(2'-hydroxy-i-dimethylaminophenyl)-3-(2'-methoxy-5fuchlorf) enil)
Phthalide 3-(2'--Hydroquine-41-dimethylaminophenyl) -:s-(2'-7toxy5'-diI-lophenyl)tutaride 3-(2'-Hydroquine-4'-dimethylaminophenyl) -3-(2'-7-57-methylphenyl)phthalide3-(2'-MeI-xyisomethylaminophenyl)-3-(2'-hydroxy-4'-chloro-5-methylphenyl)phthalideThis invention In , the leuco dye is applied to a support,
Normally 03~50vA? 72, preferably 05-305'
It is used at a rate of about 7m".

The receptor sheet used in the present invention has a receptor layer containing a color developer for the leuco dye on a support such as paper, synthetic paper, or plastic film. In this case, as the color developer, an electron-accepting substance such as a phenolic substance, an organic acid or its +j Ru. Specific examples of the color developer suitably applied in the present invention are shown below. Note that the numbers in parentheses indicate the melting point.

4-teri-butylphenol (98), 4-human[koxydiphenyl ether (84), 1-naphthol (98), 2-naphthol (121), methyl-4-hydroxybenzony 1.(13) ), 4-hydroxyacetophenone (109), 2,2'-dihydroxydiphenyl ether (79), 4-phenylphenol (1
66), 4-Te-octylcatechol (109)
, 2.2'-dihydroxydiphenyl (105), 4.
4'-methylenebisphenol (]60), 2,2'-
Methylenebis(4-chlorophenol) (+6i), 2
．． 2'-methylenebis(4-methyl-6-1, crt-
butylphenol) (125), 4,4'-isopropyritine diphenol (156), 4,4'-impropyritine bis(2-chlorophenol) (90), 4.4
'-isopropyritine bis(2,6-dibromophenol) (1,72), 4,4'-inpropyritine bis(
2-tert-butylphenol) (110), 4.4
'-Isopropyritine bis(2-=methylphenol)
(13(i), 41i'-impropyritinbis(2°6-dimethylphenol) (168), 4,4'-
sec-butylidene diphenol (++!, 1)
, 41 i'-Secondary-butylidene bis(2-methylphenol) (N2), 4, 4'-cycloheginritin diphenol (180), 7 II i'-cyclohexylitine bis (2-methylphenol) (+Sa) , salicylic acid (163), salicylic acid meta-IJ ester (74), phenacyl salicylate (110), 4-
Hydrogeiabenzoic acid methyl ester (+31), 4-hydroxybenzoic acid butyl ester (+16), 4-hydroxybenzoic acid propyl ester (98), 4-hydroxybenzoic acid isopropyl ester (86), 4-hydroxybenzoic acid butyl ester ( 7I), 4-hydroxybenzoic acid isoamyl ester (50), 4-hydroxybenzoic acid phenyl ester (178), 4-hydroxybenzoic acid benzyl ester (111), /I-hydroxybenzoic acid cyclohexyl ester (119), 5-
Human-9ACn tyroxysalicylic acid (200), 5-chlorosalicylic acid (
172), 3-chlorosalicylic acid (178), thiosalicylic acid (164), 2-riorJ-5-1- ■-
+benzoic acid (165), 4-methoxyphenol (5:
().

2-hi)'roxybenzyl alcohol (87), 2゜5
-dimethylphenol (75), benzoic acid (122),
Or-l-)ruylic acid (107), meta]-ruylic acid (I
ll), paratoluic acid (18]), orthochlorobenzoic acid (142), metaoxybenzoic acid (200), 2,
4-dihydroxyacetophenone (97), resorcinol monobenzony 1-(135), 4-hydroxybenzophenone (133), 2,4-dihydroxybenzophenone (144), 2-naphthoic annod (184), ]-]hydroxy-2- naphthoic annod 195), 3,4-dihydroxybenzoic acid ethyl ester (128), 3,4-dihydroxybenzoic acid phenyl ester (189), 4-hydroquine propiophenone (150), zarycyl salicylate ( 148),
Phthalic acid monobenzyl ester (107).

-10- When a transfer layer or a receptor layer is provided on each support, a binder commonly used in 1 to 1 is used, and examples include:
(e+) Vinyl alcohol, methoxycellulose, hydroquine ethylcellulose, carboxymethylcellulose, polyvinylpyrrolidone, polyacrylamide;, polyacrylic acid, starch, gelatin, polystyrene, vinyl chloride-vinyl acetate copolymer, polybutyl methacrylate Ray
1. K J+'] may be water-centered, organic solvent soluble or aqueous emulsion forming.

In the present invention, the receptor layer contains a porous filler.
I can even stir it. When a porous filler is contained in the receiving layer, the heat-melting reaction component from the transfer layer quickly transfers to the receiving sheet side, and an image is formed on the receiving sheet side, while a small amount of transfer occurs. Even if the coloring reaction between the leuco dye and the color developer takes place sufficiently on the porous filler,
A remarkable increase in the density of the colored image is achieved. In this case, the porous filler must have a specific oil absorption amount, specifically, 50 ml/ ] 00 jil-(J
ISI (according to 5101 method) or more, preferably] 50 m
171009 or more are used. Examples include inorganic and organic fine powders such as Noriyoku, aluminum silicate, alumina, aluminum hydroxide, magnesium hydroxide, urea-formalin lt fat, and styrene resin. part, 0.05 to 10
It is used in a proportion of 0.1 to 3 parts by weight, particularly from the viewpoint of thermal sensitivity and image density.

In the present invention, the transfer layer and, if necessary, the receiving layer have a melting point of 200C or less, preferably 150C.
Thermofusible substances having melting points of: The amount used is 01 to 50 parts by weight per 1 part by weight of the leuco dye. The thermofusible substances preferably used in the present invention are as follows.

(1) Fatty acid amides R, INHCOR2(I) represented by the following general formula (I) or (It) (wherein R, "U, alkyl group having 1 to 30 carbon atoms, R
51°] 1. ″ is an alkyl group having 10 to 30 carbon atoms, T(
, ', R5 is hydrogen or a lower argyl group) Specific examples of such fatty acid amides include the following.

Decylacetamide, decylpropionamide, undenyl acetamide, lanticylpropionamide, lauryl acetamide, lauryl propionamide, tridecylacetamide middle propionamide, myristylacetamide, myristylpropionamide, pentadecyl acetamide, pentadecyl propionamide, palmitylacetamide , palmitylpropionamide, palmitylbutyramide, heptyllace I amide, heptylgropionamide, stearylacetamide, stearylpropionamide, stearylbutyramide, stearylvaleramide,
Ste = 1 3 = Allylcapronamide, stearyllaurinamide, stearylpalmitinamide, stearylstearinamide, nonadecylacetamide, nonadecylpropionamide, behenylacetamide, behenylpropionamide, behenylstearamide, undecanoic acid methylamide, undecanoic acid ethylamide, laurin acid methylamide, lauric acid ethylamide, l-ritecanoic acid methylamide, tridecanoic acid ethylamide, myristic acid methylamide, myristic acid ethylamide, pentatecanoic acid methylamide, pentadecanoic acid ethylamide, palmitic acid methylamide, palmitic acid dimethylamide, palmitic acid butylamide, stearic acid methylamide, Stearic acid ethylamide, stearic acid propylamide, stearic acid butylamide, stearic acid dimethylamide, stearic acid diethylamide, stearic acid dibutylamide, nonadecanoic acid methylamide, nonadecanic acid ethylamide, behenic acid methylamide, oleic acid methylamide, oleic acid ethylamide.

(2) Aromatic carboxylic acid amides 1 represented by the following general formula (ml) are also 0 (in the formula, 11 and 6 are alkyl groups having 1 to 3 carbon atoms, 1 (
・7,1 (・” id, hydrogen, halogen, lower alkyl group or lower alkokene group, n is O or 1) Specific examples of such compounds include those shown below. It will be done.

N-sudearylbenzamide, N-palmityl-2-chlorobenzamide, N-stearyl-2-meth)quinbenzamide, N-stearyl-4-methylbenzamide, N-palmityl-2,4-dimethylbenzamide Amide, N
-Behenylbenzamide, N-behenyl-2-methylbenzamide, N-sudearylphenylacetylamide,
N-Behenylphenylacetylamide.

(3) Amides having a cyclohexyl ring represented by the following general formulas (IV) and (V) (wherein R9 is an alkyl group having 1 to 30 carbon atoms or a substituted or unsubstituted oryl group, RIO is hydrogen, halogen or lower alkyl group) (in the formula, 1%11 is a carbon number of 1
~3o alkyl group, 1%] 2 is hydrogen, halogen, or lower alkyl group) Specific examples of such compounds include those shown below.

N-Cyclohexylacetamide, N-cyclohexylpropionamide, N-cyclohexylstearamide, N-cyclohexylrubensoamide, N-cyclohexol-2-methylbenzamide, N-7chlorohexyl-2-chlorobenzamide, N-cyclohexamide xyl-2,
4-dimethylbenzamide, N-cyclohexylpalmitic acid amide, N-(chlorohegicyl)valmitic acid amide, N-(2-methylcyclohexyl) stearic acid amide, N-stearylhexahydrobenzamide.

(4) Phenyl esters of hydroxybenzoic acid represented by the following general formula (■) (where xH, halogen, argyl group or alkokene group having 1 to 30 carbon atoms, halokene, substituted or unsubstituted aryl or aralkyl group, a substituted or unsubstituted aryloxy group, a carboxylic acid group or a hydroxyl group, n is 0, 1.2 or 3, m
is 1, 2 or 3) Specific examples of such compounds include those shown below.

4-Hydroxybenzoic acid phenyl ester, 417- -hydroxybenzoic acid (2-methquinphenyl) ester, 4-hydrogine benzoic acid (2-7 4-methylphenyl) ester, 4-hydroxybenzoic acid (3,
5-dioxyphenyl) ester, 3-hydroginebenzoic acid (4-carbogynphenyl) ester, 4-hydroxybenzoic acid H(4-methquinphenyl) ester, 4-
hydrogine benzoic acid (4-chlorphenyl) ester,
Salicylic acid (2-chlorophenyl) ester −+j
IJ thylic acid (4-chlorophenyl) ester, IJ
salicylic acid (2,3-dichlorophenyl) ester, salicylic acid (2,6-dichlorophenyl) ester, salicylic acid (2,4,6-)dichlorophenyl) ester, salicylic acid (2-bromophenyl) ester, salicylic acid (2,4,6-dichlorophenyl) ester,
4-bromophenyl) ester, salicylic acid (2,4-
dibromophenyl) ester, salicylic acid (2,6-dibromophenyl) ester, salicylic acid (2,4,6-
) dibromophenyl) ester, salicylic acid (3-methylphenyl) ester, salicylic acid (2,4-di 18
- methylphenyl) ester, salicylic acid (4-tert-butylphenyl) ester, salicylic acid (4-1-sha IJ -f mylphenyl) ester, salicylic acid (
2-MeI xyphenyl) Nisder, the IJ f fluoric acid (
2-(1-xyphenyl) ester, IJ (3-methoxyphenyl) ester, 1) -f-(4-hydroxyphenyl) ester, salityl f
f1(4-benzylphenyl)ester, ”)-1J
salicylic acid (4-<nsoylphenyl) ester, salicylic acid (2-7togy7-4--allylphenyl) ester, salicylic acid (alpha naphthyl) nisder, salicylic acid (beta naphthyl) ester, -IJ IJ-f- (410 rho-3-methylphenyl) ester, salicylic acid (3-hydroginphenyl) ester, salicylic acid (4-propenylphenyl) ester, 5-chlorosalicylic acid (3-methylphenyl) ester, 3.5-/chlorosalicylic acid (2'-methquinphenyl)ester.

(5) Benzoic acid phenyl esters -10- represented by the following general formula IVII) (where 1(, +3 is hydrogen, alkyl # group having 1 to 30 carbon atoms also L 1. Closed, nitrile group, acyloxy group, substituted or unsubstituted aryl or aralgyl group, substituted or unsubstituted aryloxy or aralkyloxy group, B+4 is hydrogen, alkyl group or alkoxy having 1 to 30 carbon atoms basis,
Examples of such compounds include halogen, nitro group, nitrile group, acyloxy group, substituted or unsubstituted aryl or aralkyl group, substituted or unsubstituted aryloxy or aralkyloxy group, or butyl group) For example, the following can be mentioned.

Benzoic acid phenyl ester, benzoic acid-4-methylphenyl ester, benzoic acid-2,4-dichlorophenyl ester, benzoic acid-2,4,6-trichlorophenyl ester, benzoic acid-2-methyl-4-chlorophenyl ester Ester, benzoic acid-3-pro! , phenyl ester, benzoic acid-2,4=cyfuromphenyl ester, benzoic acid
l-3-E-dophenyl ester, benzoic acid-3-nitrophenyl ester, benzoic acid 4) f-2,
6-/chlorphenylestenopebenzoic acid-4-isopropylphenyl ester, benzoic acid-4-butylphenylnisder, benzoic acid 4-benzylphenyl ester, benzoic acid-4-(1-naphthyl)phenyl ester, benzoic acid-2-benzoyloxyphenyl ester, benzoic acid-4-(2-methyl)diphenyl ester,
Benzoic acid-2-phenylethyloxyphenyl ester, benzoic acid-2-aceI xyphenyl ester, benzoic acid-4-methoxyphenyl ester, benzoic acid-4-
(4-Methyl)phenoxyphenyl ester, 41f-benzoic acid phenyl ester, 4-methoxybenzoic acid phenyl ester, 4-phenol-20-xybenzoic acid phenyl ester, 4-aceI xybenzoic acid phenyl ester, 4 -Me]・xybenzoic acid-4-
Methoxyphenyl ester, 2-acetoxybenzoic acid phenyl ester, 2-benzyloxybenzoic acid phenyl ester, 2-nitrobenzoic acid-4-methylphenyl ester, 4-nidobenzoic acid-4-methylphenyl ester, 4- Benzyloxybenzophenone, 2-benzyloxy-4-methylbenzophenone.

(6) Benzoyloxybenzoic acid esters represented by the following general formula (4) (wherein B+5 is hydrogen, an argyl group or alkoxy group having 1 to 30 carbon atoms, or a halogen, and R+6 is a carbon number of 1 to 30)
30 alkyl groups, substituted or unsubstituted aryl or aralkyl groups A) Specific examples of such compounds include those shown below.

4-penzoyloxybenzoic acid methyl ester, 4-penzoyloxybenzoic acid ethyl ester, 4-peizoyluogine benzoic acid-n-propyl ester, 4-penzoyloxybenzoic acid hensyl ester, 4-penzoyloxybenzoic acid phenyl ester, 2 -Penzoyluoquine benzoic acid phenyl ester, 4-(4'-methylbenzoyluoquine)benzoic acid ethyl esternope 4- (<
Benzoic acid ethyl ester, 4-(4'-chlorobenzoyluogine)benzoic acid ethyl ester.

Furthermore, in the present invention, in order to provide a transfer medium with higher thermal sensitivity, the transfer layer and/or receiving layer containing the thermofusible substance may be formed by forming the transfer layer and/or the receiving layer during or after the layer formation. heat b] heat treatment at a temperature higher than the melting point of the melting substance,
It is advantageous to heat-melt the thermofusible substance once;
Furthermore, when forming a transfer layer containing leuco dye I,
It is also a preferable means to use a coating liquid containing a leuco dye in dissolved form.

In the thermal transfer medium of the present invention, each layer forming liquid is prepared by dispersing and dissolving the above-mentioned layer forming components together with a solvent such as water using a pulverizing and mixing means such as a ball mill or attritor, and this is placed on each support on a dry side. It can be obtained by coating and drying to a coating weight of 03 to 30 Vrn, calendering the surface of the resulting transfer sheet and/or receiving sheet, and adjusting the surface smoothness to 200 to 1000 seconds. can.

In the transfer/-1 used in the present invention, the transfer layer provided on the surface may be a so-called plain (no image) layer provided uniformly over the entire surface of the support.
It may be provided in advance in the form of a desired image. A transfer sheet having an image-free transfer layer can be obtained by simply applying a transfer layer forming liquid to the surface of a support.

On the other hand, those with an image-like transfer layer have a
The transfer layer forming liquid can be applied in the form of a desired image (including characters) by letterpress printing or gravure printing, or it can be applied on the transfer sheet without an image. Lay a suitable support surface such as paper, synthetic paper, plastic film, etc. on the surface of the transfer layer, and press a suppressor such as a typewriter or iron pen, a thermal head, a thermal pen, etc. from the support or transfer sheet side. is pressed in an image-like manner by means of heating suppression means,
The imageless transfer layer of the transfer notebook can be obtained by imagewise imprinting on the surface of another suitable support.

To carry out the thermal transfer of the present invention, for example, when using a transfer sheet having an image-shaped transfer layer, a receiving sheet is placed on the surface of the transfer layer so that the receiving layer is in contact with the surface of the transfer layer, and then this is rolled with a heating roll. You can do this by saying,
On the other hand, when using a transfer notebook with a transfer layer without an image, the receiving layer of the receiving sheet is overlaid on the transfer layer surface of the transfer sheet, and printing is directly performed using a thermal printer from the back side of the transfer sheet. 25': Alternatively, the receiving layer of the receiving sheet can be superimposed on the transfer layer of the transfer note, and the transfer sheet 25'
, 17-4, with the original drawing written in black ink adhered to the back side of the book.
This can be done by irradiating infrared rays from the receiving sheet side and selectively heating only the black image area in the original image to a high temperature (in this case, the transfer sheet and the receiving sheet). must be transparent to infrared radiation).

In thermal transfer as in the present invention, by repeating the above operations using the same transfer notebook,
Multiple copies can be easily obtained. In addition, when obtaining multicolor copies, create transfer sheets with leuco dyes of different tones as the main coloring components, for example, create a transfer sheet with blue leuco dye and a transfer sheet with red leuco dye, and create the same transfer sheet. If a transferred image is formed by transfer onto the receiving sort, blue and red colored images can be formed on the same sheet.

In the present invention, since the leuco dye and its color developer are contained on separate supports, the leuco dye and its color developer are contained in separate supports, so that the leuco dye and its color developer are contained at the time of manufacture and storage, unlike conventional thermal paper.
-26- The problem of color development fog did not occur at all, and furthermore, the obtained copy contained only a color developer and no leuco dye in the non-image area, so it was possible to heat it. No color development occurs (ie, it is completely fixable). It is economical because high-density images can be obtained with a small amount of heating energy, and many copies can be made.

Next, the present invention will be explained in more detail with reference to Examples.

Example 1 Crystal violet lactone 20j% N-stearylbenzamide 201 ethyl cellulose (
+09J water 1i) 40Ft water
After dispersing the composition consisting of 200p for 24 hours using a ball mill, it was coated on the surface of a 12μ thick roughened polyester film using a wire bar and dried to form a dye layer with a sealing amount of 12g/m゛. A transfer sheet was created.

Bring the coated surface of the transfer sheet into contact with the high-quality paper, and apply the printing pressure of the typewriter keys from behind the high-quality paper.
A mirror-image transfer image C.I. was created.

On the other hand, n-butyl 4-hydroxybenzoate 20g ester silica fine particles 151 water
2001 was dispersed for 24 hours using a ball mill, and then applied to the surface of high-quality paper (35 F/1 m') using a wire bar and dried to form a receiving layer with a sealing amount of 3 P/m'. A receiving sheet with a smoothness of 800 seconds was prepared by calendering (receiving sheet A).

For comparison, a receiving sort was prepared in the same manner except that no calendaring was performed (receiving sheet B).

However, a blue colored image was obtained. Further, the above operation was repeated 10 times using the same transfer image/print 12 to obtain a transfer image. Macbeth density reduction (old) of the obtained image density
514). The values are shown in Table-1.

Table 1 As can be seen from Table 1, the present invention is superior to the comparative example in terms of image density and transfer efficiency when copying a large number of sheets.

Example 2 Benzoic e-'+-Methogin phenylester]5I-methylcellulose (s % water soluble W) 30
%.

water 2001
After dispersing the composition for 24 hours using a ball mill, it was applied to the roughened surface of the polyester film using a wire bar and dried to give a sealing surface of 35 ff/nX.
A dye layer of
I created a transcription note of 00 seconds.

On the other hand, 4.4'-isopropylidene diphenol 20g-urea-formalin resin fine particles +5i polyvinyl alcohol (10% water i liquid) 35P water
After dispersing the composition consisting of 20 oz for 24 hours using a ball mill, it was coated and dried using a wire bar on the surface of high-quality paper (35P/i) to form a receptor layer with a coating weight of 251', and smoothed by calendering. A receiving sheet was prepared for 650 seconds.

When the transfer layer of the transfer sheet obtained as described above and the receiving layer of the receiving sheet were placed in contact with each other, and printing was performed from the back side of the transfer sheet using a thermal printer equipped with a built-in thermal head, the results were clear. A clear black image was obtained.

Example 3 Using the crystal violet lactone chlorofluoran of the transfer sheet of Example 1, a red coloring transfer sheet was created, and a transfer image sheet having a mirror image for red coloring was prepared in the same manner as in Example 1. Created.

The surface of the receiving sheet 1-A having a clear blue image obtained in Example 1 was brought into contact with the surface of the /ζ transfer image sheet obtained in this example, and the temperature was increased from the back side of the receiving sheet by the same operation. When passed between 120C heating rolls,
Two-color transferred images, blue and red, were obtained in (i) with a clear red image.

Patent applicant Rico Co., Ltd. Agent: Patent attorney Toshiaki Ikeura − 3 1 − 475-

Claims (1)

[Claims] (1) Consisting of a transfer sheet having a transfer layer containing a leuco dye as a main component, and a receiving sheet having a receiving layer containing a color developer as a main component for the leuco dye, the transfer layer and/or the receiving layer: Surface smoothness (Beckman smoothness) 2
A thermal transfer medium characterized in that it has a time of 00 to 1000 seconds.