JPH04189189A - Thermal transfer recording medium - Google Patents

Abstract

PURPOSE:To prevent an ink layer from being transferred in the repeated printing mode and make it possible to print an image repeatedly at high quality by providing an ink layer composed mainly of a resin matrix and a thermally melting ink, either of which has mold lubrication effects upon the other, on a support. CONSTITUTION:An ink layer 31 is composed mainly of thermally melting ink and a resin matrix 7 which is given mold lubrication effects upon the thermally melting ink, or consists mainly of the resin matrix 7 and the thermally melting ink 9 which is given mold lubrication effects upon the resin matrix. The blending ratio (weight ratio) of the thermally melting ink 9 and the resin matrix in the ink layer 31 can be set properly in accordance with the printing conditions of a printer, especially the number of times of repeated printing. The ink layer 31 is formed by leaving the thermally melting ink 9 dispersed at about 30 deg.C alone at room temperature to allow ink gelation, then mixing the ink gel with a resin matrix component and applying this mixture to a support 1.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention relates to a thermal transfer recording medium, and more particularly, to a thermal transfer recording medium that can form images with high print density and little decrease in print density even after repeated use. .

[Conventional technology]

2. Description of the Related Art Recording devices such as printers and facsimiles that use a thermal transfer recording method are widely used because they can be made smaller, lower in price, and require less maintenance.

Thermal transfer recording media used in thermal transfer recording devices are generally those in which a thermal transfer ink layer (heat-melting ink layer) is simply provided on a support. There was a problem in terms of running costs because all of the information was transferred and it could not be used repeatedly. Therefore, there is a need for a thermal transfer recording medium that can be used repeatedly, and various types of thermal transfer recording media have been proposed to date.

To name a few, (+) Japanese Patent Publication No. 54-61125
3, JP-A No. 55-105579, etc., in which a fine porous ink layer is provided on a support so that hot-melt ink gradually oozes out, (2 ) A porous membrane is provided on an ink layer on a support to control the amount of ink flowing out, as disclosed in JP-A-511-212993; and (3) JP-A-60-127191. Publication No. 60-127192
A method has been proposed in which a plurality of ink layers are provided via a plurality of adhesive layers and the ink layers are gradually peeled off and transferred, as disclosed in Japanese Patent Publication No.

However, the thermal transfer recording medium of (1) above has the disadvantage that ink leaching becomes difficult and print density gradually decreases with repeated use. The thermal transfer recording medium described in (2) above has the disadvantage that when the pore diameter of the porous film is increased to increase print density, the mechanical strength decreases and the ink layer peels off. The thermal transfer recording medium (3) has a drawback in that the amount of heat-melting ink transferred is not constant for each print.

In addition, most conventional thermal transfer recording media are compatible with serial thermal heads used in recording devices such as word processors, and thermal transfer recording media such as line thermal heads used in recording devices such as facsimiles and barcode printers. It has been pointed out that when the separation time after heating between the receiving paper (=transfer paper) and the recording paper is long, the ink layer peels off and furthermore, the image density decreases.

[Problem to be solved by the invention]

An object of the present invention is to provide a thermal transfer recording medium that maintains high print density even when thermal transfer printing is repeatedly performed, and shows little decrease in density. Another object of the present invention is to provide a thermal transfer recording medium that prevents the entire transfer of an ink layer during repeated printing when a line thermal head is used and enables repeated printing with high image quality.

[Means to solve the problem]

The first aspect of the present invention is a thermal transfer recording medium provided with a heat-fusible ink layer on a support, wherein the ink layer contains a resin matrix and a heat-fusible ink as main components; One of the inks has a releasing effect on the other.

The second aspect of the present invention is a thermal transfer recording medium in which a heat-melt ink layer is provided on a support, the ink layer mainly comprising a microporous resin and a heat-melt ink, and the microporous resin, One of the hot-melt inks has a releasing effect on the other.

The third aspect of the present invention is a thermal transfer recording medium in which a heat-melting ink layer is provided on a support, the ink layer mainly consisting of a resin matrix and a heat-melting ink, and extending from the support side to the ink surface. It is formed so that the amount of the matrix increases and the amount of the heat-fusible ink decreases, and is characterized in that either the resin matrix or the hot-fusible ink has a releasing effect on the other.

A fourth aspect of the present invention is a thermal transfer recording medium having a heat-melt ink layer provided on a support, which ink layer includes a first ink layer mainly composed of a coarse branched resin and a heat-melt ink, and a fine ink layer. The branched resin and the microporous resin are partially in communication with each other, and at least the microporous resin One of the resins and the hot-melt ink is characterized in that one has a releasing effect on the other.

The inventors of the present invention have investigated thermal transfer recording media from various angles, and found that, in general, when thermal transfer is performed repeatedly using a line-type thermal head and a thermal transfer recording medium, the It was confirmed that because the timing of peeling between the thermal transfer recording medium and the receiving paper was delayed, it was difficult to maintain the balance of forces (peel strength) as shown in FIG. 5. That is, Fl is heat-fusible ink 2
2 and the tensile strength of the receiving paper 20, F2 is the heat-melting ink 2
2 and the tensile strength of the resin matrix 21, F3 is the tensile strength of the support 1
and the peel strength between resin matrix 2+/thermofusible ink 22, the relational expression F,>F2≧F3 is likely to hold true. For this reason, in conventional thermal transfer recording media, a phenomenon of total transfer of the heat-melting ink occurs, making it substantially difficult to perform repeated printing operations.

Therefore, the present inventors further investigated and found that the balance of the forces is F,>F2. Moreover, it was confirmed that the previous problem could be achieved if the thermal transfer recording medium was devised so that the condition of F3>F2 was satisfied. In the present invention, the object is basically achieved by causing either the resin matrix or the thermofusible ink forming the thermofusible ink layer to have a releasing effect on the other.

This tendency is even better observed when a coarsely branched resin or a microporous resin is used instead of the resin matrix, and furthermore, if the latter microporous resin is used, repeated printing becomes more noticeable. It indicates gender.

Resin matrix, coarse branched resin and/or microporous resin (hereinafter sometimes referred to as "resin matrix etc.")
By combining a site that exhibits a release effect with the heat-melt ink, or by incorporating a release effect-imparting agent into the resin matrix, or by adding a trix, coarse, branched, fine and/or coarse branched fine and/or The effects of the present invention (such as good repeatability of printing) are further enhanced by blending a substance that exhibits a mold release effect with the microporous resin.

2. Preferably used components that impart release action to the resin matrix, etc. (components that form a resin matrix, etc. that has an N-type action on heat-melting ink) include modified silicone resins, silicone resins, Low surface energy substances such as modified fluororesins are used alone or in combination of two or more. Alternatively, the above-described low surface energy substance may be blended with an appropriate matrix-forming resin (resin matrix, etc.). The latter is particularly preferable in consideration of affinity with heat-melting ink and mechanical strength.

stomach.

Various modified silicone resins and modified fluororesins are used to improve adhesion, mechanical strength, and compatibility with other matrix-forming resins. As the modification method, conventionally known acrylic modification, urethane modification, alkyd modification, epoxy modification, etc. are used. Polyorganosiloxane moieties and silicones exhibiting low surface energy,
Tri-, tetra-, or fluorinated ethylene moieties are bonded to these resins in a block-like or graft-like manner.

When blended with matrix-forming resins, etc. in arbitrary amounts, sites that exhibit low surface energy
is preferably formed so as to be oriented on the surface of a resin matrix or the like.

However, the most desirable substances with mold release sites include silicone oil and silicone wax made of polyorganodimethylsiloxane with epoxy groups at the ends.
Examples include those containing carboxylic acid, amine, aziridine, incyanate, etc.

As the matrix-forming resin, it is desirable to use various resins whose glass transition point is higher than the melting point of the heat-melting ink. Examples include vinyl chloride resin, vinyl chloride-vinyl acetate copolymer, polyester resin, epoxy resin, polycarbonate resin, phenol resin, acrylic resin, urethane resin, and hozoimide resin.

In particular, partially saponified vinyl chloride-vinyl acetate copolymers and maleic acid-containing vinyl chloride-vinyl acetate copolymers are preferred as resins in terms of adhesion to the support, flexibility, film strength, and glass transition point. .

The amount of the low surface energy substance that imparts a release effect to the resin matrix or the like is arbitrarily set depending on the magnitude of the cohesive force within the heat-melting ink.

Here, a specific example of preparing a resin having releasable sites will be given.

(Preparation example) Vinyl chloride-vinyl acetate copolymer containing 2% by weight of maleic acid (average molecular weight 500, glass transition point 70°C, CA manufactured by UCC) in a mixed solvent of mesel ethyl ketone/toluene. A theoretical equivalent amount of polyorganodimethylsiloxane oil (epoxy equivalent: 350, viscosity: 30 csl, manufactured by Shin-Etsu Chemical Co., Ltd., X-22-3437) having an epoxy group at one end was mixed, and the reaction was completed to obtain a resin having a releasable site. Ta.

On the other hand, heat-melt ink having a releasing effect (heat-melting ink component having a releasing effect on resin matrices, etc.) that is preferably used includes heat-melting ink, modified silicone oil, modified silicone wax, modified Low surface engineering energy vehicles (mold release vehicles) such as fluorine wax can be used alone or in combination of two or more.

Further, the above-mentioned substance exhibiting low surface energy may be blended into a suitable vehicle. The latter is preferable in consideration of colorant dispersibility and thermal properties as a heat-melting ink.

Various types of modified silicone wax and modified silicone oil can be used as long as they can satisfy the properties required for a heat-melting ink. The modifying group is preferably one that improves compatibility with other vehicles. For example, alcohol modification, polyether modification, olefin modification, amino modification, amide modification, carboxyl modification, fatty acid modification,
Carnauba modification etc. are introduced. When used alone as a vehicle for heat-melting ink, those exhibiting a melting point of 40-110°C are preferred.

Now, FIG. 1 is a schematic cross-sectional view of a thermal transfer recording medium according to the first invention. In the drawing (Figure 1), l is a support, 31 is an ink layer, and 5 is a heat-resistant slipping layer (heat-resistant protective layer).
, 7 represents a resin matrix, and 9 represents a heat-melting ink.

The ink layer 3I consists of (1) a thermofusible ink 9 and a resin matrix 7 which has a releasing effect with the thermofusible ink, or (2) a resin matrix 7 and a releasing effect with the resin matrix. The main component is a heat-melting ink 9 having a heat-melting ink.

The proportion (weight ratio) of the thermofusible ink 9 and the resin matrix in the ink layer 31 is set appropriately depending on the printing conditions of the printer, especially the number of repeated printings, but the total transfer of the thermofusible ink 9 Considering the optical density of the printed image, a range of about 70:30 to 40:60 is desirable. Further, the thickness of the ink layer 31 is appropriately determined depending on the desired number of repeated printings, and is suitably about 5 to 12 tones.

The ink layer of the type shown in FIG.
Or heat-melt ink 9 of the components (2) at about 30°C.
After dispersing the ink, leave it at room temperature to form a gel in the ink.
Subsequently, it can be formed by mixing it with a resin matrix component and coating it on the support 1.

For the support 1 in this case, conventionally known heat-resistant materials are used, such as plastic films such as polyester, polycarbonate, triacetyl cellulose, nylon, polyimide, etc., parchment paper, parchment paper, and condenser paper. can. The thickness of the support 1 is desirably about 2 to 15 μs in consideration of thermal sensitivity and mechanical strength. Also,
A heat-resistant protective layer (heat-resistant slipping layer) 5 made of silicone resin, fluororesin, polyimide resin, epoxy resin, phenol resin, melamine resin, nitrocellulose, etc. is provided on the surface of the support 1 that comes into contact with the thermal head. It is also possible to further improve the heat resistance of l.

The heat-melting ink 9 may be constructed by appropriately selecting from conventionally known colorants (dyes and pigments) and waxes. As mentioned above, releasability is imparted if necessary. As pigments, carbon blanks and phthalonoamine pigments are preferably used, and as dyes, direct dyes,
Acidic dyes, basic dyes, disperse dyes, oil-soluble dyes, etc. are preferably used.

Examples of waxes include natural waxes such as beeswax, carnauba wax, spermaceti wax, wood wax, candelilla wax, Nuka wax, and montan wax, paraffin wax, microcrystalline wax, oxidized wax, oshikerite, ceresin, and ester wax. . In addition, higher fatty acids such as margaric acid, lauric acid, myristic acid, palmitic acid, stearic acid, fromene acid, and hebenic acid; higher alcohols such as stearyl alcohol and hehenyl alcohol; esters such as fatty acid esters of sorbitan; and stearin. Examples include amides such as amide and oleamide.

FIG. 2 is a schematic sectional view of a thermal transfer recording medium according to the second aspect of the present invention. The thickness of the ink layer 32 is determined as appropriate depending on the desired number of repeated printing steps 5-1.
Approximately 2 μs is appropriate. Also, the ink layer 3 here
2 is (1') a thermofusible ink 9 and the thermofusible ink mainly composed of a microporous resin 7a having a release function, or (2') a microporous resin 7a and its microporous The resin is composed mainly of heat-melting ink 9 that has a release function. The weight ratio of the microporous resin (1') or (2') and the heat-melting ink in the ink layer 32 is preferably about 6040 to 20.80.

FIG. 3 is a sectional view of a thermal transfer recording medium according to the third aspect of the present invention. The ink layer 33 in Uni is formed by the above (1) or (2).
) is applied onto the support 1 and left in an atmosphere at a high temperature enough to melt the heat-melting ink for a long time (about 3 to 10 minutes).

This is considered to be because the uniformly dispersed ink components migrate toward the support because the specific gravity of carbon blanks and the like is high.

The ink layer 33 shown in FIG. 3 has a form quite similar to the ink layer (shown in FIG. 4) in the fourth aspect of the present invention. That is, as a result, the ink layer 33 consists of a support side portion mainly composed of coarse branched resin and hot melt ink, and a surface side portion mainly composed of fine porous resin and hot melt ink. This is because these branched resins, the microporous resin, and the support (or the adhesive layer if an adhesive layer is provided between the support and the ink layer) appear to be in partial contact with each other. be.

FIG. 4 is a sectional view of a thermal transfer recording medium according to the fourth aspect of the present invention. An ink layer 34 is laminated on the support 1 as a first ink layer 4 and a second ink layer 42. The first ink layer 41 is made of heat-melting ink 19 or coarse branched resin 15.
It is weakly held by This hot melt ink 19
It also has a mold release effect.

You don't have to hold it. The second ink layer 42 laminated on the first ink layer 41 is composed of a hot melt ink 17 and a fine porous resin 7 that have a releasing effect on the fine porous resin; It consists of a microporous resin that exhibits a mold release effect and a heat-melting ink. The heat-melting ink 17 may be the same as the ink 19 of the first ink layer or may be different.

The ratio (weight ratio) of the heat-melting ink 17.19 to the branched resin 15 or the microporous resin 7 in the first ink layer 41 and the second ink layer 42, and the thickness of each of these layers are as follows. As described in the figure, if the desired number of repeated printings, total transfer of heat-melting ink, optical density of the printed image, etc. are taken into account, the values shown in Table 1 are appropriate.

Table 1 The formation of the ink layer 32 in Fig. 2 and the first ink layer 41 and the second ink layer 42 in Fig. This is advantageously carried out by applying the mixture and drying with hot air at 50-130°C.

However, when forming the microporous resin structure and the coarse branched resin structure, the gas force of a blowing agent may be assisted. That is, the foaming agent here is preferably an azo compound that decomposes when heated and forms pores throughout the layer.
Examples include azodicarbonamide, azobisisobutylnitrile, abcyclohexylnitrile, diazoaminohene, halium azocycarboxylate, and the like.

In order to control the foaming temperature and foaming efficiency of the foaming agent, foaming aids such as zinc oxide, various stearates and palmitates, and plasticizers such as DOP may be added.

The amount of the foaming agent is not particularly specified, or it is preferably added in an amount of 1 to 30% based on the total solid content of the foam and hot-melt ink in the ink supply layer and ink transfer control layer. If the content of the foaming agent is less than the above range, sufficient pores cannot be obtained to improve the transfer ability, whereas if it is more than the above range, the mechanical strength will deteriorate, which is undesirable.

The ink layer 32.4+ or 42 of the present invention can be formed by dissolving the resin constituting the foam and the heat-melting ink in a mixed solvent of a volatile solvent and a non-volatile solvent, in addition to the method using the above-mentioned foaming agent. Alternatively, a method of forming a porous resin body by drying is also possible.

In the thermal transfer recording medium of the present invention, an adhesive layer 6 may be provided between the support 1 and each ink layer.

By doing so, the ink layer can be more firmly held on the support. Specific examples of materials constituting the adhesive layer 6 include ethylene-vinyl acetate copolymer, vinyl chloride-vinyl acetate copolymer, ethylene-acrylate copolymer, polyethylene, polyamide, polyester, petroleum resin, nylon, etc. 1 or 2 from
It is sufficient to use a combination of two or more species. The thickness is 0.2~2.
0. This is preferable from the viewpoint of adhesiveness and thermal sensitivity.

〔Example〕

Next, the present invention will be explained in more detail with reference to Examples. Note that the amounts (parts) of each component described in the Examples are parts by weight.

Example 1 A heat-resistant slipping base material was prepared by subjecting one side of a PET film (support) having a thickness of about 4.5 tones to heat-resistant slipping treatment. - Carbon blank 2.5 parts Candelilla wax 7.6 parts Polyethylene oxide 2.5 parts Terpene resin
A mixture consisting of 28.0 parts of 4E methyl ethyl ketone toluene was sufficiently dispersed in a hole mill at 30° C., and then left at room temperature to prepare a heat-melting ink component.

In addition, a 20% solution of acrylic modified silicone resin (a resin in which polyorganosiloxane (n # 180 to 200) is grafted to an acrylic vinyl monomer and copolymerized with MMA, and has an average molecular weight of 40,000) in methyl ethyl ketone. was used as a resin matrix forming component.

These heat-melting ink components and resin matrix forming components are mixed at a weight ratio of 64%, and this is applied onto the base material (support side) and dried to form a non-ink layer with a thickness of approximately 10 μs. A thermal transfer recording medium of the type shown in FIG. 1 was then produced.

Example 2 Example except that the resin matrix forming components were changed to the following]
A thermal transfer recording medium of the type shown in FIG. 1 was produced in exactly the same manner as described above.

(Resin matrix forming component) Isopropyl acrylic modified fluororesin (resin in which polytetrafluoroethylene (n#15-20) is grafted onto acrylic vinyl monomer and copolymerized with MMA, with an average molecular weight of 35,000) 20% solution of alcohol/methyl ethyl ketone (1/I) mixed solvent.

Example 3 A thermal transfer recording medium of the type shown in FIG. 1 was produced in exactly the same manner as in Example 1 except that the resin matrix components were changed as shown below.

(Resin matrix component) Acrylic modified silicone resin of Example 1 (polyorganosiloxane, n#20-40, average molecular weight 15,000
) and 95 parts of vinyl chloride-vinyl acetate copolymer in a 20% solution of methyl ethyl ketone-toluene (2% toluene) mixed solvent.

Example 4 The same heat-resistant slippery base material and heat-melting ink as in Example 1 were prepared.

Further, as the resin matrix forming component, a 20% solution of vinyl chloride-hinyl acetate copolymer in which the release sites obtained in the above preparation example were combined in a mixed solvent of methyl ethyl ketone/toluene (toluene 2%) was used.

These hot-melt inks and resin matrix forming components were mixed at a weight ratio of 64:4, and this was applied onto the base material (support side) and dried at 110°C to form an ink layer with a thickness of about 8.0 μs. A thermal transfer recording medium of the type shown in FIG. 1 was obtained.

Example 5 The same heat-resistant slippery base material as in Example 1 was prepared. On the other hand, carbon black 2.5 parts Candelilla wax 6.8 parts Oxidized polyethylene wax 9 parts Fatty acid modified silicone oil 4 parts (manufactured by Shin-Etsu Chemical Co., Ltd., X-22-80
0) Terpene resin, 4 parts methyl ethyl ketone 58.0 parts toluene
A mixture consisting of 28.0 parts was sufficiently dispersed at 30° C. in a hole mill and then left at room temperature to prepare a heat-melting ink component.

In addition, vinyl chloride-vinyl acetate copolymer (average molecular weight 2
A 20% solution of methyl ethyl ketone (0.000) was used as a microporous resin forming component.

These heat-melting ink components and the microporous resin-forming component are mixed at a weight ratio of 64%, and this is applied onto the base material (support side) and dried to form an ink layer with a thickness of about 10 μs. A thermal transfer recording medium of the type shown in FIG. 2 was prepared.

Example 6 The same procedure as shown in FIG. 2 was made in Example 5 except that the fatty acid-modified silicone oil among the heat-melting ink components was replaced with alcohol-modified silicone oil (manufactured by Shin-Etsu Chemical Co., Ltd., X-22-801). We created a type of thermal transfer recording medium.

Example 7 A second example was prepared in the same manner as in Example 5, except that among the heat-melting ink components, fatty-modified silicone oil was replaced with amide-modified silicone oil (manufactured by Shin-Etsu Chemical Co., Ltd., KF3995).
A thermal transfer recording medium of the type shown in the figure was made.

Examples 8 and 9 Among the heat-melting ink components of Example 5, the fatty-modified silicone oil was replaced with fatty acid silicone Wanoxuro Example 8 (manufactured by Shin-Etsu Chemical Co., Ltd., X-22-800)] or alcohol-modified silicone wax [Example 1] Example 9 (manufactured by Shin-Etsu Chemical Co., Ltd.,
X-22-801)] in the same manner except for replacing it with
A thermal transfer recording medium of the type shown in the previous article was made.

Example 10 Carbon blank 25 parts carnauba wax 3.4 parts Candelilla wax 3.4 parts oxidized polyethylene wax, 9 parts carnauba-modified silicone oil, 4 parts (manufactured by Shin-Etsu Chemical Co., Ltd., X-22- 350
0) A mixture consisting of 4 parts of terpene resin, 58.0 parts of methyl ethyl ketone, and 28.0 parts of toluene was sufficiently dispersed in a hole mill at 30°C and then left at room temperature to prepare a heat-melting ink component. A thermal transfer recording medium of the type shown in FIG. 2 was produced in the same manner as above.

Example 11 The same heat-resistant slippery base material as in Example 1 was prepared. A mixture of 80 parts of heat-melting ink components having the same composition as in Example 4 was applied onto this substrate (support side) and dried to form a first ink layer about 8 tones thick. Furthermore, the following mixture is coated on this first ink layer and dried to form a second ink layer about 2 tones thick, and a fourth ink layer is formed.
A thermal transfer recording medium of the type shown in the figure was made.

(Second ink layer forming liquid composition) Same thermofusible ink component as Example 4 70 parts Same microporous forming resin component as Example 5 30 parts Example 12 The thermal transfer ink layer has a two-layer structure as in Example 11. Carbon blank 2.5 parts Candelilla wax 7.6 parts oxidized polyethylene wax as the heat-melting ink components of the first ink layer.
2.5 parts terpene resin
, 4 parts methyl ethyl ketone 58
．． 0 parts toluene 28.0
After fully dispersing the mixture consisting of the following parts in a ball mill at 30°C, the mixture was left to stand at room temperature to prepare a heat-melting ink component. The first ink layer was otherwise formed in the same manner as in Example 11.

Furthermore, a second ink layer similar to that in Example 11 was formed on this first ink layer to produce a thermal transfer recording medium of the type shown in FIG.

Example 13 The same heat-resistant slippery base material as in Example 1 was prepared. On this substrate (
A mixture consisting of 70 parts of hot-melt ink components and 3 parts of azobisisobutyronitrile having the same composition as in Example 4 was applied to the support (support side) and dried at 80°C to form a first ink layer with a thickness of about 6 μs. did. Further, the following mixture was coated on the first ink layer and dried at 110° C. to form a second ink layer having a thickness of about 21 Js, thereby producing a thermal transfer recording medium of the type shown in FIG.

(Composition of second ink layer forming liquid) 70 parts of heat-melting ink component having the same composition as in Example 4 30 parts of microporous resin Example 14 The same heat-resistant slippery base material as in Example 1 was prepared. On this substrate (
A mixture consisting of 8θ parts of the heat-melting ink component having the same composition as in Example 4 and 20 parts of the same coarse branched resin component as in Example 3 was coated on the support side) and dried at 80°C to form an approximately 8 μs thick layer. One ink layer was formed. Further, the following mixture was coated on the first ink layer and dried at 110° C. to form a second ink layer having a thickness of about 2 pts, thereby producing a thermal transfer recording medium of the type shown in FIG. 4.

(Composition of second ink layer forming liquid) 70 parts of heat-melting ink component having the same composition as in Example 4 30 parts of microporous forming resin component as in Example 3 Comparative example 1 The resin matrix component in Example 1 was replaced with vinyl chloride. A comparative thermal transfer recording medium was prepared in the same manner except that vinyl acetate copolymer was used.

These 14 types of thermal transfer recording media were installed in a line printer, and the same position on the thermal transfer recording medium was repeatedly printed four times under the following conditions, and the image density each time was measured using a reflection densitometer (RD914) manufactured by Macbeth. .

[Printing conditions]

Thermal head line thin film pad type platen pressure:
230g1/cn+ Peeling angle of thermal transfer recording medium 45° (relative to transfer paper) Applied energy 23mJ#nm2 Printing speed, 2 inches/sec Transfer paper: High quality paper (Beck smoothness 450sec) Measurement results are shown in Table 2. It was as expected.

Table 2 As shown in Table 2, the images in the example had sharper edges and the peeling sound during printing was lower than that in comparative example 1. Furthermore, when the applied energy was increased and solid printing was performed, no part was observed that was completely transferred in any of the examples. In the comparative example, partial full transfer was observed in the solid area.

〔Effect of the invention〕

The thermal transfer recording medium of the present invention has a sufficiently high image density even when repeatedly printed, and furthermore, the ink layer does not peel off and the peeling sound is small, making it extremely excellent in practical use.

[Brief explanation of drawings]

1, 2, 3, and 4 are sectional views of four sides of the thermal transfer recording medium according to the present invention. FIG. 5 is an explanatory diagram of the total transfer phenomenon of heat-melting ink when used in a conventional thermal transfer recording medium. l・Support 31, 32, 33, 34 Ink layer

Claims (20)

[Claims] (1) In a thermal transfer recording medium in which a heat-melt ink layer is provided on a support, the ink layer mainly contains a resin matrix and a heat-melt ink, and either the resin matrix or the heat-melt ink is A thermal transfer recording medium characterized by having a releasing effect on the other. (2) The thermal transfer recording medium according to claim 1, further comprising an adhesive layer provided between the support and the heat-melting ink layer. (3) The thermal transfer recording medium according to claim 1 or 2, wherein the mold release action of the resin matrix is achieved by combining a mold release site with the resin matrix, or by blending a mold release action imparting agent into the resin matrix. . (4) The resin matrix is a vinyl chloride-vinyl acetate copolymer, and the release agent is an acrylic ester, a methacrylic ester grafted with a polyorganodimethylsiloxane unit, and a copolymer thereof. The thermal transfer recording medium according to claim 1, 2 or 3. (5) The thermal transfer recording medium according to claim 1 or 2, wherein the releasing action of the heat-melting ink is achieved by containing a releasing vehicle in the heat-melting ink. (6) In a thermal transfer recording medium having a heat-melting ink layer provided on a support, the ink layer mainly contains a microporous resin and a heat-melting ink, and the microporous resin,
A thermal transfer recording medium characterized in that one of the heat-melting inks has a releasing effect on the other. (7) The thermal transfer recording medium according to claim 6, further comprising an adhesive layer provided between the support and the heat-melting ink layer. (8) The mold release action of the microporous resin is achieved by combining a mold release site with the microporous resin, or by blending a mold release action imparting agent into the microporous resin. The thermal transfer recording medium described in . (9) The microporous resin is a vinyl chloride-vinyl acetate copolymer, and the release agent is an acrylic ester, a methacrylic ester grafted with a polyorganodimethylsiloxane unit, and a copolymer thereof. The thermal transfer recording medium according to claim 6, 7 or 8. (10) The thermal transfer recording medium according to claim 6 or 7, wherein the releasing action of the heat-melting ink is achieved by containing a release vehicle in the heat-melting ink. (11) In a thermal transfer recording medium in which a heat-melting ink layer is provided on a support, the ink layer mainly contains a resin matrix and a heat-melting ink, and the amount of the resin matrix increases from the support side to the surface of the ink layer. 1. A thermal transfer recording medium, characterized in that the resin matrix and the heat-melt ink are formed so that the amount of the heat-melt ink increases and the amount of the heat-melt ink decreases, and either one of the resin matrix and the heat-melt ink has a releasing effect on the other. (12) The thermal transfer recording medium according to claim 11, further comprising an adhesive layer provided between the support and the heat-melting ink layer. (13) The mold release action of the resin matrix is achieved by adding a mold release site to the resin matrix, or by blending a mold release action imparting agent into the resin matrix.
The thermal transfer recording medium according to 0. (14) The thermal transfer recording medium according to claim 11 or 12, wherein the releasing action of the heat-melting ink is achieved by containing a releasing vehicle in the heat-melting ink. (15) The resin matrix is a vinyl chloride-vinyl acetate copolymer, and the release agent is an acrylic ester, a methacrylic ester grafted with a polyorganodimethylsiloxane unit, and a copolymer thereof. The thermal transfer recording medium according to claim 11, 12 or 13. (16) In a thermal transfer recording medium in which a heat-melt ink layer is provided on a support, the ink layer consists of a first ink layer mainly composed of a coarse branched resin and a heat-melt ink, and a fine porous resin and a heat-melt ink layer. The branched resin, the microporous resin, and the support are partially in communication with each other, and at least the microporous resin, A thermal transfer recording medium characterized in that either one of the heat-melting inks has a releasing effect on the other. (17) The thermal transfer recording medium according to claim 16, further comprising an adhesive layer provided between the support and the heat-melting ink layer. (18) The mold release action of the microporous resin is achieved by combining a mold release site with the microporous resin, or by blending a mold release action imparting agent into the microporous resin. The thermal transfer recording medium described in . (19) The thermal transfer recording medium according to claim 17 or 18, wherein the releasing action of the heat-melting ink is achieved by containing a releasing vehicle in the heat-melting ink. (20) The resin matrix is a vinyl chloride-vinyl acetate copolymer, and the release agent is an acrylic ester, a methacrylic ester grafted with a polyorganodimethylsiloxane unit, and a copolymer thereof. The thermal transfer recording medium according to claim 16, 17 or 18.