JPS6264595A - Heat transfer sheet - Google Patents

Abstract

PURPOSE:To ensure that a dye is easily transferred to a transfer recording material to form a recorded image having a high density and excellent fastness even where thermal energy is applied for an extremely short period of time, by setting the ratio of inorganic property to organic property of a dye incorporated in a dye carrying layer to be not higher than a specified value. CONSTITUTION:The ratio of inorganic property to organic property (I/O) of a dye incorporated in a dye carrying layer provided on one side of a base sheet is set to be not higher than 2.30. By this, excellent thermal transferrability, excellent dyeing properties for a transfer recording material and excellent color forming properties are displayed, and neither migration of the dye nor contamination is caused in the transfer recording material to which the dye is transferred. If the I/O value exceeds 2.30, the melting point of the dye becomes extremely high, and solubility of the dye in solvents and the affinity of the dye for the transfer recording material are abruptly lowered.

Description

Detailed Description of the Invention (Industrial Application Field) The present invention relates to a thermal transfer sheet, and more specifically, provides a novel thermal transfer sheet that can easily provide a recorded image with excellent durability on a transfer material. The purpose is to

(Prior art) Various thermal transfer methods have been known in the past, among which a sublimation dye is used as a recording agent, this is supported on a base sheet such as paper to form a thermal transfer sheet, and the dye is dyed with a sublimation dye. A sublimation transfer method is used in which the thermal transfer sheet is layered on a transferable material such as polyester woven cloth, and heat energy is applied in a pattern from the back side of the thermal transfer sheet to transfer the sublimable dye to the transfer material.

(Problems to be Solved by the Invention) In the above-mentioned sublimation printing method, in which the material to be transferred is, for example, a polyester woven fabric, heat energy is applied for a relatively long time, so the material to be transferred is As a result, relatively good dye migration is achieved as a result of the heat applied to the dye.

However, with advances in recording methods, thermal heads and the like have been used to record images at high speed, such as on polyester sheets.
When using transfer materials with a dye-receiving layer on paper and forming delicate letters, figures, or photographic images on these transfer materials, the application of thermal energy is extremely short, on the order of seconds or less. Therefore, in such a short time, the sublimable dye and the transfer material are not sufficiently heated, and an image of sufficient density cannot be formed.

Therefore, in order to cope with such high-speed recording, sublimable dyes with excellent sublimation properties were developed, but dyes with excellent sublimation properties generally have small molecular weights, so they do not dissolve in the transferred material after transfer. Problems have arisen in that dyes migrate over time or bleed onto one surface, resulting in distorted or unclear images or contaminating surrounding articles.

In order to avoid such problems, if a sublimable dye with a relatively large molecular weight is used, the sublimation speed will be inferior in the high-speed recording method as described above, so it will not be possible to form an image with a satisfactory density as described above. Met.

Therefore, in thermal transfer methods using sublimable dyes,
At present, there is a strong demand for the development of a thermal transfer sheet that can provide sufficiently dense and clear images by applying thermal energy in an extremely short period of time as described above, and also exhibits excellent fastness of the formed images. It is.

As a result of intensive research in response to the strong demands of the industry as described above, the inventor of the present invention discovered that in the conventional sublimation printing method for polyester woven fabrics, etc., the surface of the woven fabric is not smooth, so the thermal transfer sheet and the transfer material cannot be used. Some woven fabrics do not adhere well, so the dye used must be sublimable or vaporizable (i.e. capable of moving through the space between the thermal transfer sheet and the woven fabric). However, when the transfer material is a polyester sheet with a smooth surface, a surface-treated paper, etc., the thermal transfer sheet and the transfer material come into close contact during thermal transfer, so only the sublimation and vaporization properties of the dye are affected. is not an absolute requirement, but the ability of the dye to migrate through the interface between the two in close contact with each other due to heat is also extremely important, and the thermal migration property of such an interface is greatly influenced by the inorganic and organic nature of the dye used. By knowing that this is the case and selecting a dye with an appropriate inorganic/organic value (hereinafter referred to as I10 value), it is possible to make dyes with molecular weights that are considered unusable according to conventional wisdom. It has been found that even if it is present, it has good heat transfer properties. By using a thermal transfer sheet that holds a dye selected according to the I10 value of the dye, the dye used can be easily transferred to the transfer material even when thermal energy is applied for an extremely short time, resulting in a high density. The present invention was completed based on the finding that a recorded image having excellent fastness can be formed.

(Means for Solving the Problems) That is, the present invention comprises a base sheet and a dye-supporting layer provided on one side of the base sheet, and the I10 value of the dye contained in the dye-supporting layer is is 2.30 or less.

Next, to explain the present invention in more detail, the dye as defined above used in the present invention and which mainly characterizes the present invention itself is a known dye, and has conventionally been used mainly as a disperse dye for polyester fibers and the like. be.

Conventionally, various disperse dyes have been used as dyes for sublimation transfer methods, but because sublimation transfer methods require a rapid sublimation rate, they are generally dyes with a molecular weight of about 300 or less, or at most about 350 or less. It has been used in a limited manner.

However, as mentioned above, although such relatively low molecular weight materials have good transfer speed and color development, they give images with low migration resistance and stain resistance as described above.

As mentioned above, the present inventor has the viewpoint that, when the thermal transfer sheet and the transferred material can be brought into sufficient contact during thermal transfer, not only the sublimation and vaporization properties of the dye but also the thermal migration properties of the dye are important. As a result of detailed research on the suitability of known disperse dyes for thermal transfer, which had previously been completely excluded from the selection for use in sublimation transfer methods, we found that the molecular weight was 300 or more or 350 or more, and that conventionally Even if it is 390 or higher, which was thought to be unusable for practical use, conventional common sense suggests that only dyes with an I10 value of 2.30 or lower according to the definition below can be used. It has excellent heat transferability, and also exhibits excellent dyeing and coloring properties on the transferred material, and also has low dye migration (bleeding) and staining properties in the transferred material. It was discovered that this dye has extremely ideal properties as a dye for thermal transfer sheets.

In addition, the "■10 value" referred to in the present invention is in accordance with "Organic Conceptual Diagram - Basics and Applications" by Yoshio Koda, published by Sankyo Publishing.

Preferred specific examples of heat-transferable dyes having the above-mentioned physical properties in the present invention are as follows.

(I) Dye compound 2 represented by the following general formula (I) and/or (II) provided that A in the formula is a hydrogen atom, -CONHR4 (R4 is a hydrogen atom or an alkyl group), ≧ mino group It is. ), -COCH2C0Rfl (RE
I is an alkyl group. ) or -〇〇N-Ph 雛 (R7 is a hydrogen atom or an alkyl group),
XI and x2 are hydrogen atoms or halogen atoms, and R1
is a hydrogen atom or an alkyl group, R2 and R3 are an alkyl group or a substituted alkyl group, and B,! : C hydrogen atom, -CONHR4, -COR8, -COOR8
, amino group, alkylamino group or acylamino group.

Such dyes are known materials in themselves, and are obtained by an oxidative coupling method of P-aenylenediamine compounds and naphthols or phenols. It was used as a coloring agent.

Particularly preferred formula (I) or (
In the dye n), A and B are -CONHR4,
It was found that R4 was an alkyl group of CI-CB, and R1 was a hydrogen atom or a methyl group.

Furthermore, regarding R2 and R3, both are Cl-C
4 alkyl group, and at least one of R2 and R3 is a hydroxyl group or a substituted hydroxyl group [e.g. -〇-R
'(R'' is a lower alkyl group, alkylcarbonyl group, etc.)
], amino group or substituted amino group [e.g. -NH-R
``(R'' is an alkyl group, an alkylcarbonyl group, an alkylsulfonyl group, etc.)], a cyano group, a nitro group, etc., will give the best results, i.e., excellent sublimation property, and a substrate. It had excellent dyeability on sheets, heat resistance during transfer, color development, and excellent migration resistance.

(rI) Particularly suitable azo dyes include those having the following structure.

4H9 (MW-444110-0,84) (MW-41? l10-0.[f5) (MW-50
5,8110-0,fll)01豐-508,9110
-0,88)(MW-473,5110=0.73)(
Sugi 1-533. ! 3 1/D-0,92) (MW=50
5.9 l10=0.98) (MW-51L5 11
0-0.93) (Mlil-419l10-1.02)
(MW-844110-0,57) (MW-458l10-0.59) (III) Anthraquinone dyes Particularly suitable examples include those having the following structures.

(MW-468I10-1.42) (MW-454110-1,77) (MW-422l10-0.88) (MW-418110-0,72) (MW-418110 supplement, 72) (MW-3tl18 l10= 0.83) (MW-53
4I10 0.89) (MW-443l10=0.81) (TV) Imidoanthraquinone dye represented by the following general formula (m) provided that R1 in the above formula represents a hydrogen atom or an alkyl group of 01 to C20. , R2 represents a hydrogen atom, an amino group or an alkyl-substituted amine group of 01 to C20, and X is O
or NH group, and Ra represents an alkyl group of 01 to G20, and the alkyl group is a hydroxyl group, 01 to C20
or a C2-C20 alkoxy group having an R4-0- group (wherein R4 is a hydrogen atom or a C1-C20 alkyl group).

Particularly suitable examples include those having the following structure.

(MW-321l10-1.72) (MW-391110=1.33) (MW-379l10-1.51) (Decoy=393110=1.44) (MW-393l10-1.44) ^ (MW-384110-1,34) Convex (MW-392110-1,22) (MW-379110-1,51) (MW-394110-1,32) (V) Other dyes Particularly suitable dyes include the following dyes.

(MW-418l10=0.34) (MW-515l10-0.52) (sho d-374l10-0.98) 2H5 (MW-3!39 l10-0.90) (MW-334
l10-1.133) Among the dyes exemplified above and dyes other than those exemplified that can be used in the present invention, preferable ones have an l10 value of 1.20 or less, more preferably 1.00 or less, and a molecular weight of about 300. or more, more preferably 350 or more, most preferably 390 or more
~800. When the l10 value is 2.30 or more, the melting point of the dye becomes extremely high, and the solubility in solvents and the affinity for the transfer material decrease rapidly. The drawbacks have not been fully resolved, and those with a molecular weight exceeding 800 tend to have poor thermal transfer speed and color development.
Undesirable.

Regarding the relationship between the l10 value and molecular weight, the theoretical basis is unknown, but if the l10 value is 2.30 to 1.20, the tolerable heat is determined when the molecular weight is 350 or more, preferably 390 or more. Migration properties and satisfactory image durability are achieved, and l10 values are below 1.20, preferably 1.
00 or less, satisfactory heat transfer properties and acceptable image durability were achieved even with molecular weights of about 300 to 390.

The thermal transfer sheet of the present invention is characterized by using the above-mentioned specific heat-transferable dye, and the other structure may be the same as that of conventionally known thermal transfer sheets.

The base sheet used in the construction of the thermal transfer sheet of the present invention may be any conventionally known material having a certain degree of heat resistance and strength, for example 0.5 to 50 J
Lm, preferably paper with a thickness of about 3 to 10 pm, various processed papers, polyester films, polystyrene films,
Examples include polypropylene film, polysulfone film, polycarbonate film, polyvinyl alcohol film, cellophane, and particularly preferred is polyester film.

The dye-supporting layer provided on the surface of the base sheet as described above is a layer in which the heat-transferable dye is supported by an arbitrary binder resin.

As the binder resin for supporting the heat-transferable dye as described above, any conventionally known binder resin can be used. Preferred examples include ethyl cellulose, hydroxyethyl cellulose, ethyl hydroxy cellulose, hydroxypropyl cellulose, methyl cellulose, Cellulose resins such as cellulose acetate and cellulose acetate, vinyl resins such as polyvinyl alcohol, polyvinyl acetate, polyvinyl butyral, polyvinylpyrrolidone, and polyacrylamide, polyesters, etc. are preferred from the viewpoint of heat resistance, dye migration, etc. It is.

The dye-carrying layer of the thermal transfer sheet of the present invention is basically formed from the above-mentioned materials, but may also contain various conventionally known additives as required.

Such a dye-supporting layer is preferably prepared by adding the heat-transferable dye, binder resin, and other optional components to a suitable solvent and dissolving or dispersing each component to prepare a coating liquid or ink for forming the support layer. This is formed by applying and drying this onto the above-mentioned base sheet.

The compatible layer formed in this way has a thickness of 0.2 to 5.0 pm,
Preferably 0.4-2. The thickness is about OILm, and the heat-transferable dye in the support layer is 5 to 70% of the weight of the support layer.
It is suitably present in an amount of 10% to 60% by weight.

The thermal transfer sheet as described above is fully useful in the present invention as it is, but it may also be provided with an anti-adhesive layer, that is, a release layer, on the surface of the dye-carrying layer. This prevents the adhesion of the thermal transfer sheet and the transferred material during the process, and uses a higher thermal transfer temperature.
Images with even better density can be formed.

As this mold release layer, even if an inorganic powder with anti-adhesive property is simply adhered, it has a considerable effect, and it is also possible to use resins with excellent mold release properties such as silicone polymers, acrylic polymers, and fluorinated polymers. It can be formed by providing a release layer of 0.01 to 57 gm, preferably 0.05 to 2 gm.

Incidentally, the above-mentioned inorganic powder or releasable polymer exhibits a sufficient effect even when included in the dye-carrying layer.

Furthermore, a heat-resistant layer may be provided on the back surface of such a thermal transfer sheet of the present invention in order to prevent adverse effects caused by the heat of the thermal head.

The transfer material used to form an image using the thermal transfer sheet of the present invention may be any material as long as its recording surface has dye receptivity to the above-mentioned dyes. If the material is paper, metal, glass, synthetic resin, etc., which does not have a dye, a dye-receiving layer may be formed on at least one surface thereof.

Examples of transfer materials that do not require the formation of a dye-receiving layer include polyolefin resins such as polyethylene and polypropylene, halogenated polymers such as polyvinyl chloride and polyvinylidene chloride, polyvinyl alcohol, polyvinyl acetate, and polyacrylic ester. vinyl polymers such as polyethylene terephthalate, polyester resins such as polybutylene terephthalate, polystyrene resins, polyamide resins, copolymer resins of olefins such as ethylene and propylene with other vinyl monomers, ionomers,
Examples include cellulose resins such as cellulose diacetate and cellulose triacetate, li&fibers, woven fabrics, films, sheets, and molded products made of polycarbonate, polysulfone, polyimide, and the like.

Particularly preferred are sheets or films made of polyester or processed paper provided with a polyester layer. In addition, in the present invention, even if the transfer material is non-dyeable such as paper, metal, glass, etc., a solution or dispersion of the dyeable resin as described above is coated on the recording surface and dried.
Alternatively, by laminating these resin films, it can be used as a transfer material.

Furthermore, even if the transfer material has the dyeability described above, a dye-receiving layer may be formed on the surface thereof from a resin having better dyeability, as in the case of the paper described above.

The dye-receiving layer formed in this manner may be formed from a single material or from a plurality of materials, and may also contain various additives as long as the object of the present invention is not hindered. Of course.

Such a dye-receiving layer may have any thickness, but generally has a thickness of 5 to 50 jLm. Although such a dye-receiving layer is preferably a continuous coating, it may also be formed as a discontinuous coating using a resin emulsion or a resin fraction.

Such a transfer material is basically as described above and can be used as is, but it is possible to incorporate an inorganic powder for anti-adhesion into the transfer material or its dye-receiving layer. In this way, even if the temperature during thermal transfer is increased, adhesion between the thermal transfer sheet and the material to be transferred can be prevented, and even better thermal transfer can be performed. Particularly preferred is finely powdered silica.

Further, in place of or in combination with the inorganic powder such as silica, a resin as described above having good mold release properties may be added.Particularly preferred mold release polymers include cured products of silicone compounds, such as Examples include cured products made of epoxy-modified silicone oil and amino-modified silicone oil.

Such release agents may be present in an amount of about 0.5 to 3 by weight of the dye-receiving layer.
It is good that it accounts for 0% grinding.

In addition, the transfer material used is on the surface of the dye-receiving layer.
An inorganic powder such as those described in 2 above may be attached to enhance the anti-adhesive effect, or a layer made of a mold release agent having excellent mold release properties as described above may be provided.

Such a release layer exhibits a sufficient effect at a thickness of about 0.01 to 5 μm, and can further improve dye receptivity while preventing adhesion to the dye receptive layer of the thermal transfer sheet. can.

Any conventionally known means for applying thermal energy can be used to apply thermal energy when performing thermal transfer using the thermal transfer sheet of the present invention and the recording material as described above. By controlling the recording time using a recording device such as a thermal printer TN-5400),
The object of the present invention can be fully achieved by applying thermal energy of about 1.0 mm/mml.

In particular, in the thermal transfer sheet of the present invention, the thermal transfer sheet and/or the material to be transferred is heated to a temperature of about 40 to 100° C. in advance or simultaneously at the time of transfer, as in the method described in Japanese Patent Application No. 60-050660 by the applicant of the present invention. It has been found that when recording as described above is carried out after heating, even better transfer speed and higher recording density can be achieved. Therefore, the thermal transfer sheet of the present invention is particularly useful for use in the method described in Japanese Patent Application No. 60-050660.

(Effect e) According to the present invention as described above, as already partially described, the specific dye used in the composition of the thermal transfer sheet of the present invention is a heat-transferable dye ( Although it has a significantly higher molecular weight of 300 or more, 350 or more, or even 390 or more compared to the molecular weight of about 150 to 300), it exhibits excellent heat transferability, dyeing property on the base sheet, and coloring property. This is because the dye was selected based on the I10 value, which easily becomes migratory due to the heat during transfer and has a high affinity for the material to be transferred.

Therefore, by selecting a dye with such specific physical property values, the transfer of the dye during transfer can be carried out sufficiently even in a very short time, and after transfer, there is no possibility that the dye will transfer into the transfer material or bleed out on the surface. There's nothing to do.

Therefore, images formed using the thermal transfer sheet of the present invention have excellent fastness, especially migration resistance and stain resistance, so that even if stored for a long period of time, the sharpness of the formed image may be impaired or other defects may occur. The various problems of the prior art have been satisfactorily solved without contaminating the articles.

Next, the present invention will be explained in more detail with reference to Examples and Comparative Examples. In the first sentence, parts or % are based on weight unless otherwise specified.

Examples 1 to 5 An ink composition for forming a dye-carrying layer having the following composition was prepared, and a dry coating amount of 1, og7rrI' was applied to a 9uLm thick polyethylene terephthalate film whose back side was heat-resistant treated.
The thermal transfer sheet of the present invention was obtained by coating and drying so as to obtain a heat transfer sheet of the present invention.

Dyes listed in Table 1 below 3 parts Polybutyral resin 4.5 parts Methyl ethyl ketone 46.25 parts I.Luene
46.25 parts Next, using synthetic paper (Yubo FPG #150, manufactured by Tamago Yuka Co., Ltd.) as a base sheet, a coating liquid having the following composition was applied to one side of the paper at a dry rate of 4.5 g/rrr'. A transfer material was obtained by coating at a ratio of 100° C. and drying at 100° C. for 1 minute.

Polyester resin (V71on103, manufactured by Toyobo, τg=47°C) 0.
8 parts EVA polymer plasticizer (Elvaloy 741P, manufactured by Mitsui Polychemicals, Tg=-
37°C) 0.2 parts Amine-modified silicone (KF-857, manufactured by Shin-Etsu Chemical) 0.04 parts Epoxy-modified silicone (KF-103, manufactured by Shin-Etsu Chemical) 0.04 parts Methyl ethyl ketone/toluene/cyclohexanone (by weight Ratio 4:4:2) 9, 0 parts The thermal transfer sheet of the present invention and the transfer material described above are placed one on top of the other with their respective dye-carrying layers and dye-receiving surfaces facing each other. Applied voltage 10V, printing time 4.
Recording was performed with a thermal head under the condition of 0 m5ec, and the results shown in Table 1 below were obtained.

- is L'' - disturbance - support -1 1ヱ dan 45 and -1Inm1'VV λmu I and 1.32 0.59 0,88 0.9
0 0.841 kg OO
4, R4=n-butyl group, R1=hydrogen, R2=ethyl group, R3=ethyl group dye-tl (I10 value=0.
98, molecular weight 403).

Dye ■ is a dye in which A=-CONHR4, R4=n-propyl group, R1=methyl group, R2=ethyl group, and R3=ethyl group (I10 value=0.9fi, molecular weight 40
3).

dye MIINf, similarly A=-coNHR4, R4=n
-butyl group, R1=hydrogen, R2=ethyl group, R3=C2
It is a dye of H4NH3O2CH3 (■10 value = 1.
39, molecular weight 495).

Dye (3) is a dye in which A=-CONHR4, R4=n-butyl group, R1=methyl group, R2=ethyl group, and R3=hydroxyethyl group (I10 value=1.12.
Molecular weight 433).

Dye ■ is a dye in which A=-CONHR4, R4=n-propyl group, R1=hydrogen, FL2=methyl group, and R3=methyl group (I10 value=1.10, molecular weight 3E1
1).

In addition, in both dyes, xl and x2 are hydrogen atoms.

Examples 6 to 8 In place of the dyes in Examples 1 to 5, the general formula (11
) was used as the substituent shown below, and the other conditions were the same as in Examples 1 to 5, and excellent results were obtained in the same manner as in Examples 1 to 6.

-Kan 42- [- Kazumi-'' 1-1- mJLH May l Sumi B C
0N) lc4) 1!11 CONH2NHCOC:
4H9CNHCOCH3NHC4H9NHC:H3RI
G) 13 HHR2C2H5C2
H3C2H5 R3C2N5 C2H4OHC2H4N)ICH
GXI HHC statement molecular weight 424 383 445.5I
10 value 1.33 1.45 1.17 Examples 9 to 12 In place of the dyes in Examples 1 to 5, the above-mentioned dyes were used, and the other conditions were the same as in Examples 1 to 5. Got the results.

-3sa1≦2areL- Moxibustion 1-lI II m ■ Release l
Ω1 degree 2.07 0.58 2.0B
1.11-Souvenir ooo.

Color - 11 tones Yellow Red Red Indigo Sho, Dyework is the dye of the above formula (1).

Dye (3) is a dye of formula (3) above.

Dye (3) is a dye of formula (8) above.

Dye (2) is a dye of formula (9) above.

Example 13 The following results were obtained in the same manner as in Example 1, except that the composition of the ink for forming the dye-carrying layer was changed as shown below.

Dye of the formula 13 table 3 parts Polybutyral resin 4.5 parts Methyl ethyl ketone 25.35 parts Toluene
25.35 parts N,N-dimethylformamide 43
．． 80 parts Color development degree: 1.21, fastness: O1 Color tone: red Example 14 The dye of formula 14 was used in place of the dye of Example 13,
The rest was the same as in Example 13, and the following results were obtained.

Color density: 1.26, fastness 20, color tone: red Example 15
~22 The dyes described above were used in place of the dyes in Examples 1 to 5, and the results shown in Table 4 below were obtained in the same manner as in Examples 1 to 5.

41 - and - 1I II III rV moxibustion 5I and 1.01 0.91 0.91 0
．． 28-Kouji ooo.

Color - 11 tone Purple Purple Green Akaho Trans U Osen---Ryo VVT ■■ku''
Ω” degree 0.40 0.48 +, 12
0.88 ken” twice ooo.

Color - 11 tones Green Yellow Red Black side, dye ■ is the dye of formula (15).

Dye (1) is a dye of formula (16) above.

Dye (1) is a dye of formula (17) above.

Dye (1) is a dye of formula (18) above.

Dye V is a dye represented by formula (19) above.

Dye (1) is a dye of formula (10) above.

Dye (1) is a dye of formula (11) above.

Dye (1) is a dye of formula (12) above.

Examples 23 to 27 The results shown in Table 5 below were obtained in the same manner as in Examples 1 to 5, except that the composition of the ink for forming the dye carrying layer was changed as shown below.

Dyes listed in Table 5 below 1 part Polybutyral resin 4.5 parts Methyl ethyl ketone 25.35 parts Toluene
25.35 parts Tetrahydrofuran 43
．． 80 parts-n sheet 1e- Sad-J I II III IT
Vi” L] L 0.88 1.02 0.95 0
．． 88 0.951-"--1OΔ 000 L" 藍藍藍藍藍 The dyestuff is the dye of formula (22) above.

Dye (2) is a dye of formula (23) above.

Dye (2) is a dye of formula (24) above.

Dye (2) is a dye of formula (2B) above.

Dye V is a dye represented by formula (27) above.

Comparative Examples 1 to 7 The dyes shown in Table 6 below were used as the dyes in Examples 1 to 5, and the other conditions were the same as in Example 1 to obtain the results shown in Table 6 below.

Ichiriki46j[--L"L]L ゆ ヱ dan A and--1I"II'Ill'rV'lbloodi
ll 1.713 04B +, Q3
Q, 40U Δ Δ × Δcolor-
---tone Red Purple Blue-purple Purple base ヱ□ V"Vl'■' □ 1.12 0.88 0.57 □ (I10
value = 0.77, molecular weight 314).

Dye ■′ is Disburs Violet 1 (I
10 value = 1.34, molecular weight 238).

did.

The dye ■' is Disbirds or Violet 4 (Equation 10 value = 1.25, molecular weight 252).

The dye ■' is Disverse Bio L'y) 28 (Equation 10 value = 1.10, molecular weight 305).

Dye V' is Disburs Yellow 7 (Technique 10
value=0.54, molecular weight 332).

The dye ■' is 6 dispers yellow 23 (process 1
0 value = 0.57, molecular weight 318).

The dye ■' is Disverse Blue 26 (I10
f=1.80, molecular weight 298).

In addition, the color density in the above is a value measured with a ten sheet meter RD-918 manufactured by Macbeth Corporation in the United States.

Claims (5)

[Claims] (1) Consisting of a base sheet and a dye-carrying layer provided on one side of the base sheet, the inorganic/organic ratio of the dye contained in the dye-carrying layer is 2.30 or less. Thermal transfer sheet. (2) The thermal transfer sheet according to claim (1), wherein the dye has a molecular weight of 300 or more. (3) The thermal transfer sheet according to claim (1), wherein the dye has a molecular weight of 350 or more. (4) The thermal transfer sheet according to claim (1), wherein the dye has a molecular weight of 390 to 800. (5) The thermal transfer sheet according to claim (1), wherein the inorganic/organic ratio of the dye is 1.20 or less. (5) The thermal transfer sheet according to claim (1), wherein the inorganic/organic ratio of the dye is 1.00 or less.