JPH1067174A - Thermal transfer recording method, theramal transfer medium, and manufacture thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a thermal transfer recording method, a thermal transfer recording medium, and the manufacture thereof capable of achieving a high quality of recording images and casing less pressure contact fouling even in situations where a line type end face thermal head is employed. SOLUTION: The thermal transfer recording method is that a thermal transfer recording medium with a thermal transfer ink layer provided on the carrier is put into close contact with a medium to be recorded, and the thermal transfer ink layer is selectively heated by a line type end face thermal head in accordance with image signals, and then the thermal transfer medium and the medium to be recorded are torn off, so that a thermal transfer ink layer melted and softened on the image is transferred on the medium to be recorded. In this instance, the separation strength of the transfer layer is made 120g/cm or more at 25 deg.C, and the glossiness of the transfer layer surface is made 70% or less.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermal transfer recording method using a line-type end face thermal head, and more particularly to a thermal transfer recording medium preferably used for the thermal transfer recording method and a method for producing the same.

[0002]

2. Description of the Related Art In general, in a thermal transfer recording method, a thermal transfer recording medium having a thermal transfer ink layer on a surface of a support is used, and the thermal transfer ink layer of the thermal transfer recording medium is brought into close contact with a recording medium and comes into contact with the back side of the support. By selectively heating the thermal transfer ink layer by a thermal head according to an image signal, the thermal transfer ink layer melted or softened into an image is transferred onto a recording medium to form a recorded image on the recording medium. is there. A thermal transfer recording apparatus using such a thermal transfer recording method is widely used because of its relatively simple mechanism, small size and light weight, and excellent operability and maintainability. Recently, a line-type end face thermal head has been used as a thermal head in a thermal transfer recording apparatus in order to increase the recording speed and improve the quality of recorded images. Is disadvantageous in that pressure contact contamination is more likely to occur than in the case where a conventional thermal head is used. That is, FIG.
As shown in (a), when the conventional thermal head 40 is used, the thermal transfer recording medium 3 and the recording medium 2 are pressed between the thermal head 40 and the platen roll 50 by surface contact. When a line-type end face thermal head is used, as shown in FIG. 3B, the thermal transfer recording medium 3 and the recording medium 2 are located between the heating element 201 of the line-type end face thermal head 20 and the platen roll 50. The thermal transfer recording medium 3 is pressed against the recording medium 2 by line contact.
When the recording operation is stopped with the thermal transfer recording medium and the recording medium sandwiched between the line-type end face thermal head and the platen roll and the recording is stopped for a long time, the thermal transfer ink layer is transferred to the recording medium, Is liable to occur.

[0003]

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to solve such a problem. Even when a line-type end face thermal head is used, the recording image quality is excellent, and the occurrence of pressure contact contamination is small. An object of the present invention is to provide a thermal transfer recording method, a thermal transfer recording medium particularly preferable for use in the thermal transfer recording method, and a method for manufacturing the same.

[0004]

According to the present invention, first, a thermal transfer recording medium having a thermal transfer ink layer on a support is brought into close contact with a recording medium, and the thermal transfer ink layer is bonded by a line type end face thermal head. In a thermal transfer recording method in which the thermal transfer recording medium and the recording medium are peeled off after being selectively heated in accordance with an image signal, and the molten or softened thermal transfer ink layer is transferred onto the image on the recording medium, 25 ° C
The thermal transfer recording method is characterized in that the peel strength of the transfer layer is 120 g / cm or more and the glossiness of the surface of the transfer layer is 70% or less. Second, a thermal transfer recording medium having a thermal transfer ink layer on a support is brought into close contact with a recording medium, and the thermal transfer ink layer is selectively heated according to an image signal by a line-type end face thermal head, and then the thermal transfer recording medium is heated. In a thermal transfer recording method in which a thermal transfer ink layer melted or softened on an image is peeled off from a recording medium and transferred onto the recording medium, the transfer layer has a peel strength at 25 ° C. of 120 g.
/ Cm or more, and the glossiness of the surface of the transfer layer is 70% or less. Third, in the thermal transfer recording medium, the thermal transfer ink layer is a thermoplastic resin provided on the first ink layer mainly composed of a resin and a heat-fusible substance provided in contact with the surface of the support, 3. The thermal transfer recording medium according to the second aspect, comprising an uppermost ink layer containing a heat-fusible substance and a colorant. Fourthly, the resin in the first ink layer is at least one of a polyester resin, a polyvinyl acetal resin, a polyvinyl butyral resin, or a vinyl chloride-vinyl acetate copolymer. Is provided.
Fifth, the thermal transfer recording medium according to the fourth feature, wherein a glass transition temperature of the polyester resin in the first ink layer is 30 ° C. or less. Sixth, in the thermal transfer recording medium, the heat-meltable ink layer is provided in contact with the surface of the support, the heat-meltable substance and the release layer containing a resin as a main component, and the thermoplastic layer provided on the release layer. 3. The thermal transfer recording medium according to the second aspect, comprising an ink layer containing a resin, a heat-fusible substance, and a colorant. Seventh, the resin in the release layer is a polyester resin, a polyvinyl acetal resin,
7. The thermal transfer recording medium according to the sixth aspect, wherein the thermal transfer recording medium is at least one of a polyvinyl butyral resin and a vinyl chloride-vinyl acetate copolymer. Eighthly, the thermal transfer recording medium according to the seventh aspect, wherein the glass transition temperature of the polyester resin in the release layer is 30 ° C. or less. Ninth, a coating liquid obtained by mixing a heat-meltable substance dispersion liquid obtained by mechanically dispersing a powdery heat-meltable substance in a solvent and a resin solution is coated on a support and dried. According to a second aspect, there is provided a method for manufacturing a thermal transfer recording medium.

The inventors of the present invention have developed a thermal transfer ink layer having a thermal transfer ink layer in which the adhesion between the surface of the thermal transfer ink layer and the recording medium caused by pressure contact is smaller than the sum of the shear strength and the peel strength of the thermal transfer ink layer. It has been found that, by using a recording medium, even in a thermal transfer recording method using a line-type end face thermal head, it is possible to perform thermal transfer recording with excellent recorded image quality and with less occurrence of pressure contact stains, which led to the present invention. It is.

[0006] Here, the shear strength of the thermal transfer ink layer means the force when the thermal transfer ink layer is broken in the longitudinal direction, and the peel strength of the thermal transfer ink layer means the strength when the thermal transfer ink layer is broken in the longitudinal direction. Means the force when the thermal transfer ink layer is broken in the lateral direction from the site.

The adhesion between the surface of the thermal transfer ink layer and the recording medium, the shear strength of the thermal transfer ink layer, and the peel strength of the thermal transfer ink layer can be measured by the methods shown in FIGS. .

FIG. 1 is a schematic explanatory view showing a method for measuring the adhesion force between a thermal transfer ink layer and a recording medium. The recording medium 2 (with a smoothness of 2400 ± 150 seconds) is placed on a support 1. (Mirror coated paper) is placed thereon, and the thermal transfer ink layer surface of the thermal transfer recording medium 3 is placed in contact with the recording medium 2 and placed thereon, via a rubber plate 4 (of a size of 2 cm × 0.7 cm). Pressing is performed by the pressing plate 5 with a load of 29 kg for 5 minutes. Then, after the pressurization is released, a weight 6 is attached to the thermal transfer recording medium 3, the weight of the thermal transfer recording medium 3 required for the thermal transfer recording medium 3 to be peeled from the recording medium 2 is measured, and the weight per unit width (g / c) is measured.
m) is the adhesion between the thermal transfer ink layer and the recording medium.

FIG. 2 is a schematic explanatory view showing a method for measuring the shear strength of the thermal transfer ink layer and the peel strength of the thermal transfer ink layer. The thermal transfer recording medium 3 having the thermal transfer ink layer 8 on the support 7 is shown in FIG. The thermal transfer ink layer 8 is adhered to the thermostatic plate 10 with an adhesive tape 9, the temperature of the thermostatic plate is set to a measurement temperature of 25 ° C., and the support 7 is pulled from the thermal transfer ink layer 8 in the direction of the pulling direction 30 cm in the pulling direction 11. / Sec, and the force (g / cm) required to shear or peel off the thermal transfer ink layer 8 is measured by a tension gauge.

The glossiness of the surface of the transfer layer in the present invention is measured at a measurement angle of 85 ° using a variable angle glossmeter VGS-1001DP (Nippon Denshoku Industries).

A thermal transfer recording medium having a thermal transfer ink layer in which the adhesive force between the surface of the thermal transfer ink layer and the recording medium caused by pressure contact is smaller than the sum of the shear strength and the peel strength of the thermal transfer ink layer, It can be obtained by incorporating a resin having a function of strongly bonding the thermal transfer ink layer to the support in the layer, and increasing the peel strength of the thermal transfer ink layer when no heat is applied. That is, such a thermal transfer recording medium has a thermal transfer ink layer formed by laminating two or more ink layers on a support, and a thermal fusible substance provided with the thermal transfer ink layer provided in contact with the support surface. And a transfer recording medium comprising a first ink layer containing a resin as a main component and an uppermost ink layer containing a thermoplastic resin and a thermofusible substance, the transfer layer having a peel strength at 25 ° C. of 120 g / cm or more. And a glossiness of the surface of 70% or less. 25 ° C of the transfer layer
When the peel strength is less than 120 g / cm and the glossiness of the surface exceeds 70%, the adhesive strength between the surface of the thermal transfer ink layer and the recording medium caused by pressure contact is determined by the shear strength of the thermal transfer ink layer and the shear strength of the thermal transfer ink layer. It becomes larger than the sum of the peel strength, and the thermal transfer recording method using the line type end face thermal head causes pressure contact contamination.

As the thermal transfer ink layer in this thermal transfer recording medium, for example, an intermediate ink layer mainly composed of a colorant, a heat-fusible substance and / or a thermoplastic resin is provided between the first ink layer and the uppermost ink layer. Provided, an intermediate ink layer containing a heat-fusible substance and / or a thermoplastic resin as a main component between the first ink layer and the uppermost ink layer, and a colorant contained in the uppermost ink layer, a colorant Having an intermediate ink layer and a top ink layer mainly composed of a heat-fusible substance and / or a thermoplastic resin on a first ink layer containing
Examples include a layer in which a layer mainly containing a thermoplastic resin and a heat-fusible substance is provided on the first ink layer containing a colorant.

As a particularly preferred thermal transfer ink layer, a heat-fusible substance and a resin provided in contact with the surface of the support are mainly composed of a release layer and a release layer, since the structure is simple and the production is easy. And an ink layer containing a thermoplastic resin, a heat-fusible substance and a colorant.

As the resin in the first ink layer or the release layer, it is desirable to use a resin having high adhesiveness which does not cause pressure contact dirt. Examples of such a resin include unvulcanized rubbers such as isoprene rubber, butadiene rubber, ethylene propylene rubber, butyl rubber, and nitrile rubber; and polyolefin resins such as ethylene-vinyl acetate copolymer and ethylene-ethyl acrylate copolymer. , Others, polyurethane resin, polyacrylic resin, polyester resin, polyvinyl acetal resin, polyvinyl butyral resin, vinyl chloride-vinyl acetate copolymer, cellulose resin, phenolic resin, petroleum resin and the like, and these may be used alone or Two or more kinds may be used in combination.

Among these resins, voids are formed by using at least one of polyester resin, polyvinyl acetal resin, polyvinyl butyral resin, vinyl chloride vinyl acetate copolymer, cellulose resin, phenol resin and petroleum resin. Small and sharp images can be obtained. Further, when a polyester resin having a glass transition point of 30 ° C. or lower is used, the pressure contact stain is further reduced.

In particular, the thermal transfer recording medium produced by dispersing a heat-dissipating property and a resin solution by mechanical dispersion, which is a production method according to the present invention, can be prepared by another dispersion method even if the same material is used. Superior in pressure contact contamination compared to manufactured ones.

The first ink layer or the release layer is used to improve the releasability between the support and the thermal transfer ink layer when the thermal transfer ink layer melted or softened into an image is transferred onto a recording medium. The first ink layer or the release layer is hard at room temperature so that it melts by application of heat from the thermal head to become a low-viscosity liquid and breaks easily near the interface between the heated part and the non-heated part. A heat-meltable substance that melts when heated is used. The heat-fusible substance in the first ink layer or the release layer is preferably in the form of particles.

Examples of the heat-fusible substance include carnauba wax, candelilla wax, rice wax,
Natural waxes such as beeswax, wood wax, whale wax, montan wax, synthetic waxes such as paraffin wax, microcrystalline wax, oxidized wax, polyethylene wax, margaric acid, lauric acid, myristic acid,
Examples include higher saturated fatty acids such as palmitic acid and stearic acid, higher saturated alcohols such as stearyl alcohol and behenyl alcohol, higher saturated esters such as fatty acid esters of sorbitan, and higher fatty acid amides such as stearamide and oleamide.

The content of the resin in the first ink layer or the release layer is preferably 30% by weight or less, more preferably 1% by weight or more and 15% by weight or less based on the weight of these layers.
When the amount is less than 1% by weight, smearing occurs, and when the amount is more than 30% by weight, the quality of a recorded image deteriorates. The content of the heat-fusible substance in the first ink layer or the release layer is preferably from 50 to 99% by weight, more preferably from 80 to 95% by weight based on the weight of these layers. If the amount is less than 50% by weight, the releasability deteriorates, and if the amount is more than 99% by weight, press-contact stains are generated.

Next, the uppermost ink layer, an intermediate ink layer provided between the first ink layer and the uppermost ink layer or an ink layer provided on the release layer will be described. Thermoplastic resins used in these ink layers include ethylene-vinyl acetate copolymer, ethylene-ethyl acrylate copolymer, polyamide, polyester, polyurethane, polyvinyl chloride, various cellulose derivatives, polystyrene, polybutyral, and phenol resin. , Epoxy resin and the like.

The thermoplastic resin can increase the shear strength of the ink layer and improve the strength against rubbing of the recorded image. In addition, an ethylene-vinyl acetate copolymer or an ethylene-ethyl acrylate copolymer is preferable for forming a thermal transfer image with excellent image quality on a low-smooth recording medium, or for improving high-speed printing characteristics,
Ethylene-vinyl acetate copolymer is particularly preferred. The content of the thermoplastic resin varies depending on the thermal melting characteristics of the thermoplastic resin, but is 20 to 90% by weight based on the weight of each ink layer.
, And particularly preferably 40 to 70% by weight.

Examples of the heat-fusible substance include carnauba wax, natural waxes such as candelilla wax, rice wax, beeswax, wood wax, whale wax, montan wax, paraffin wax, microcrystalline wax, and oxidized wax. , Synthetic waxes such as polyethylene wax, higher saturated fatty acids such as margaric acid, lauric acid, myristic acid, palmitic acid and stearic acid, higher saturated alcohols such as stearyl alcohol and behenyl alcohol, higher saturated esters such as fatty acid esters of sorbitan, stearin Examples include higher fatty acid amides such as acid amide and oleic acid amide. In order to increase the strength of the recorded image against rubbing, it is preferable to use carnauba wax, candelilla wax or the like having a low penetration.

In order to improve the thermal transfer sensitivity,
The melting start temperature at the time of applying heat is 40 ° C. or more, preferably 50 ° C.
The above wax at a temperature of up to 120 ° C. may be used. The content of the heat-fusible substance is optional depending on the balance with the thermoplastic resin, but is preferably from 10 to 60% by weight, particularly preferably from 20 to 50% by weight, based on the weight of each ink layer.

As the colorant, an appropriate one can be selected from carbon black, organic pigments, inorganic pigments, and various dyes according to the required color tone and the like.
The content of the colorant is not particularly limited, but is preferably from 10 to 50% by weight of the weight of each ink layer in order to improve the strength against rubbing of the recorded image, and the shear strength of the ink layer is not excessively reduced. Is preferably 10 to 20% by weight. Further, for the purpose of roughening the surface of the thermal transfer ink layer, polyethylene, silica, alumina, calcium carbonate or the like may be added as a filler. However, when a filler is used, the adhesive strength between the surface of the thermal transfer ink layer and the recording medium decreases, but the shear strength of the ink layer may also decrease. is there. When a filler is used, it is desirably 10% by weight or less based on the weight of the ink layer.

As the support of the thermal transfer recording medium, a known film or paper may be used as it is, and for example, a relatively heat-resistant material such as polyester such as polyethylene terephthalate, polycarbonate, triacetyl cellulose, nylon and polyimide. Good plastic film, cellophane, parchment paper, etc.
Polyester such as polyethylene terephthalate is particularly preferred from the viewpoint of the adhesiveness of the ink layer and the release layer.

A protective layer may be provided on the back surface of the support, if necessary. The protective layer is a layer for protecting the support from high temperatures when heat is applied by the thermal head.In addition to thermoplastic resins and thermosetting resins with high heat resistance, UV-curable resins and electron beam-curable resins are also used. For example, a fluorine resin, a silicone resin, a polyimide resin, an epoxy resin, a phenol resin, and a melamine resin can be used.

To produce the thermal transfer recording medium of the present invention, the first ink layer, the intermediate ink layer and the uppermost ink layer are formed on a support by a hot melt coating method, an aqueous coating method, a coating method using an organic solvent, or the like. The thermal transfer ink layer may be formed by laminating or laminating the release layer and the ink layer.

In particular, as a method of applying the first ink layer or the release layer, 1) a heat-fusible substance obtained by melting a heat-fusible substance under heating with a solvent and then cooling to precipitate particles of the heat-fusible substance. A method using a coating liquid in which a substance particle dispersion and a resin solution are mixed. 2) Coating in which a resin composition and a heat-fusible substance particle dispersion in which a powdery heat-fusible substance is mechanically dispersed in a solvent are mixed. Although there is a method using a liquid, etc., the method 2) is more preferable. According to the method 2), the first ink layer or the release layer having more excellent adhesiveness can be formed, and the thermal transfer ink layer having more excellent peel strength when no heat is applied can be formed. In addition, it is possible to better prevent press contact dirt. The reason for this is that according to the method 1), the hot-melt substance dissolved in the solvent is present in the hot-melt substance particle dispersion, and this is contained in the resin contained in the first ink layer or the release layer. According to the method 2), the adhesion to the support is hindered. However, according to the method 2), it is because the heat-fusible substance dissolved in the solvent does not exist or is extremely small in the heat-fusible substance particle dispersion. Conceivable.

The thermal transfer ink layer formed by such a coating method has a total thickness of preferably 0.1 to 10 μm, particularly preferably 0.5 to 6.0 μm. In addition, the thickness of each layer is 0.2 to 3.0 μm for the first ink layer or the release layer.
m, especially 1.0 to 2.0 μm, and the ink layer formed thereon is 0.5 to 6.0 μm, especially 0.8 to 2.0 μm.
~ 3.0 µm is preferred.

[0030]

EXAMPLES The present invention will be described below in more detail with reference to examples, but the present invention is not limited thereto.

Example 1 A carnauba wax particle dispersion obtained by mechanically dispersing 85 parts by weight of a powder type carnauba wax in toluene and a toluene solution of 15 parts by weight of ethylene vinyl acetate resin (MI: 2.5 dg / min) were mixed. Thus, a coating solution for a release layer was prepared. This coating solution was applied on a 4.5 μm-thick polyester film and dried at 40 ° C. to form a 1.5 μm-thick release layer. Subsequently, a coating liquid in which the following ink layer composition was dissolved and dispersed in toluene was applied on the release layer, and dried at 40 ° C. to form an ink layer having a thickness of 1.5 μm to prepare a thermal transfer recording medium. (Composition for ink layer) Coloring agent: carbon black 20 parts by weight Thermoplastic resin: ethylene-vinyl acetate copolymer 40 parts by weight (MI: 15 dg / min) Wax: carnauba wax 35 parts by weight Filler: polyvinyl chloride powder 5 parts by weight The obtained thermal transfer recording medium was measured for peel strength and surface glossiness by the methods described above. The results are shown below. Peel strength (25 ° C.): 210 g / cm Gloss (85 °): 58%

Example 2 A carnauba wax particle dispersion obtained by mechanically dispersing 75 parts by weight of a powder type carnauba wax and 10 parts by weight of carbon black in toluene and an ethylene vinyl acetate resin (MI:
(2.5 dg / min) and 15 parts by weight of a toluene solution were mixed to prepare a coating solution for a release layer. Apply this coating solution to a thickness of 4.
The composition was applied on a 5 μm polyester film and dried at 40 ° C. to form a 1.5 μm thick first ink layer. Then, a coating liquid obtained by dissolving and dispersing the following ink layer composition in toluene was applied on the release layer, dried at 40 ° C., and
A μm ink layer was formed to prepare a thermal transfer recording medium. (Composition for uppermost ink layer) Coloring agent: carbon black 20 parts by weight Thermoplastic resin: ethylene-vinyl acetate copolymer 40 parts by weight (MI: 15 dg / min) Wax: carnauba wax 35 parts by weight Filler: polyvinyl chloride 5 parts by weight of powder The peel strength and the surface gloss of the obtained thermal transfer recording medium were measured by the methods described above, and were found to be 140 g / cm for peel strength (25 ° C.) and 52% for gloss (85 °).

Example 3 In Example 1, an ethylene vinyl acetate resin (MI:
A thermal transfer recording medium was prepared in the same manner as in Example 1 except that a vinyl chloride-vinyl acetate copolymer (Tg: 72 ° C.) was used instead of 2.5 dg / min). Next, when the peel strength and the surface gloss of this thermal transfer recording medium were measured, the peel strength (25 ° C.) was 120 g / cm, and the gloss (85)
°) 58%.

Example 4 In Example 1, an ethylene vinyl acetate resin (MI:
2.5dg / min) instead of polyester resin (T
g: 72 ° C.), except that a thermal transfer recording medium was prepared in the same manner as in Example 1. Next, when the peel strength and the surface glossiness of this thermal transfer recording medium were measured, the peel strength (25 ° C) was 130 g / cm and the glossiness (85 °) was 58%.

Example 5 In Example 1, an ethylene vinyl acetate resin (MI:
2.5dg / min) instead of polyester resin (T
g: 4 ° C.), except that a thermal transfer recording medium was prepared in the same manner as in Example 1. Next, when the peel strength and the surface glossiness of this thermal transfer recording medium were measured, the peel strength (2
(5 ° C.) 160 g / cm, gloss (85 °) 58%.

Example 6 A carnauba wax particle dispersion in which 85 parts by weight of carnauba wax was melted in toluene under heating and then cooled to precipitate carnauba wax particles, and 30 parts by weight of a polyester resin (Tg: 4 ° C.) in 30 parts by weight of toluene The coating solution for the release layer was prepared by mixing with the dissolving solution. This coating solution is 4.5 μm thick.
And dried at 40 ° C. to form a 1.5 μm-thick release layer. Subsequently, a coating liquid in which the following ink layer composition was dissolved and dispersed in toluene was applied on the release layer, and dried at 40 ° C. to form an ink layer having a thickness of 1.5 μm to prepare a thermal transfer recording medium. (Composition for ink layer) Coloring agent: carbon black 20 parts by weight Thermoplastic resin: ethylene-vinyl acetate copolymer 40 parts by weight (MI: 15 dg / min) Wax: carnauba wax 35 parts by weight Filler: polyvinyl chloride powder 5 parts by weight When the peel strength and the surface glossiness of the obtained thermal transfer recording medium were measured by the methods described above, the peel strength (25 ° C) was 150 g / cm and the glossiness (85 °) was 58%.

Comparative Example 1 A coating liquid in which the following ink layer composition was dissolved and dispersed in toluene was applied to a 4.5 μm-thick polyester film.
After drying at 0 ° C., an ink layer having a thickness of 1.5 μm was formed to prepare a thermal transfer recording medium. (Composition for ink layer) Coloring agent: carbon black 20 parts by weight Thermoplastic resin: ethylene-vinyl acetate copolymer 40 parts by weight (MI: 15 dg / min) Wax: carnauba wax 35 parts by weight Filler: polyvinyl chloride powder 5 parts by weight The peel strength and the surface gloss of the obtained thermal transfer recording medium were measured in the same manner as in Example 1. As a result, the peel strength (25 ° C.) was 170 g / cm and the gloss (85 °) was 82%.

Comparative Example 2 A carnauba wax particle dispersion obtained by mechanically dispersing 85 parts by weight of a powder type carnauba wax in toluene was mixed with a toluene solution of 15 parts by weight of ethylene vinyl acetate resin (MI: 2.5 dg / min). Thus, a coating solution for a release layer was prepared. This coating solution was applied on a 4.5 μm-thick polyester film and dried at 70 ° C. to form a 1.5 μm-thick release layer. Subsequently, a coating liquid in which the following ink layer composition was dissolved and dispersed in toluene was applied on the release layer, and dried at 40 ° C. to form an ink layer having a thickness of 1.5 μm to prepare a thermal transfer recording medium. (Composition for uppermost ink layer) Coloring agent: carbon black 20 parts by weight Thermoplastic resin: ethylene-vinyl acetate copolymer 40 parts by weight (MI: 15 dg / min) Wax: carnauba wax 35 parts by weight Filler: polyvinyl chloride 5 parts by weight of powder The peel strength and the surface gloss of the obtained thermal transfer recording medium were measured in the same manner as in Example 1. The peel strength (25 ° C.) was 130 g / cm and the gloss (85 °) was 72%. .

Comparative Example 3 A carnauba wax particle dispersion in which 85 parts by weight of carnauba wax was melted in toluene under heating and then cooled to precipitate carnauba wax particles, and an acrylic resin (T
g: 20 ° C.) 15 parts by weight of a toluene solution was mixed to prepare a release layer coating solution. This coating solution was applied on a 4.5 μm-thick polyester film and dried at 40 ° C. to form a 1.5 μm-thick release layer. Subsequently, a coating liquid in which the following ink layer composition was dissolved and dispersed in toluene was applied on the release layer, and dried at 40 ° C. to form an ink layer having a thickness of 1.5 μm to prepare a thermal transfer recording medium. (Composition for ink layer) Coloring agent: carbon black 20 parts by weight Thermoplastic resin: ethylene-vinyl acetate copolymer 40 parts by weight (MI: 15 dg / min) Wax: carnauba wax 35 parts by weight Filler: polyvinyl chloride powder 5 parts by weight The peel strength and the surface gloss of the obtained thermal transfer recording medium were measured in the same manner as in Example 1. As a result, the peel strength (25 ° C.) was 90 g / cm and the gloss (85 °) was 58%.

COMPARATIVE EXAMPLE 4 A carnauba wax particle dispersion in which 85 parts by weight of carnauba wax was melted in toluene under heating and then cooled to precipitate carnauba wax particles, and an acrylic resin (T
g: 20 ° C.) 15 parts by weight of a toluene solution was mixed to prepare a release layer coating solution. This coating solution was applied on a 4.5 μm-thick polyester film and dried at 70 ° C. to form a 1.5 μm-thick release layer. Subsequently, a coating liquid in which the following ink layer composition was dissolved and dispersed in toluene was applied on the release layer, and dried at 40 ° C. to form an ink layer having a thickness of 1.5 μm to prepare a thermal transfer recording medium. (Composition for ink layer) Coloring agent: carbon black 20 parts by weight Thermoplastic resin: ethylene-vinyl acetate copolymer 40 parts by weight (MI: 15 dg / min) Wax: carnauba wax 35 parts by weight Filler: polyvinyl chloride powder 5 parts by weight When the peel strength and the surface glossiness of the obtained thermal transfer recording medium were measured in the same manner as in Example 1, the peel strength (25 ° C) was 70 g / cm and the glossiness (85 °) was 72%.

Each of the thermal transfer recording media produced in Examples and Comparative Examples was evaluated for the smearing of press contact and the quality of recorded images by the following methods.

(Measurement method of pressure contact dirt) A thermal transfer recording medium is mounted on a label printer equipped with a line type end face thermal head, and a thermal transfer recording medium is commercially available at a press contact pressure of 300 g / cm between the line type end face thermal head and a platen roller. The mirror-coated paper (Beck smoothness: 2400 seconds) was sandwiched and pressed, and after 1 minute and 3 minutes after the pressing time, the pressure was released and the pressure-contact stain on the mirror-coated paper was visually evaluated according to the following criteria. Table 1 shows the results.

(Evaluation Criteria for Pressure Welding Contamination)。 No pressure welding contamination after 3 minutes of pressing time. ○ There is no pressure contact stain after 1 minute of pressure contact time, and there is pressure contact stain after 3 minutes of pressure contact time, but it is not noticeable. Δ: There was a slight amount of smeared contact after 1 minute. C: The welding stain after one minute of the welding time is clearly recognized.

(Measurement Method of Recorded Image Quality) A thermal transfer recording medium was mounted on a label printer equipped with a line-type end face thermal head (distance from applying heat to the thermal head until peeling off the thermal transfer recording medium and the recording medium: 210 μm). And thermal transfer recording was performed under the following thermal transfer conditions, and the quality of the thermal transfer recorded image formed on the recording medium was evaluated according to the following criteria. Table 1 shows the results.

(Thermal transfer conditions) Printing speed: 254 mm / sec Winding force: 43 g / cm Recording medium: Commercially available mirror-coated paper (Beck smoothness 2400
(Second) (Evaluation criteria of recorded image quality) ボ There is no void or blur, and the edge of the image is sharp. ○ There is no void or blur. △ There are some voids. × There are many voids and characters are difficult to read.

[0046]

[Table 1]

As is clear from Table 1, when the thermal transfer recording medium of the embodiment is used, thermal transfer recording which is excellent in recorded image quality and hardly causes press-contact stain can be performed. In particular, a polyester resin having a glass transition temperature of 4 ° C. is used as the resin in the release layer, and a coating solution obtained by mixing a resin solution with a carnauba wax particle dispersion obtained by mechanically dispersing powdery carnauba wax in toluene is used. When a layer is formed, it is possible to perform thermal transfer recording excellent in recorded image quality and prevention of pressure contact contamination.

[0048]

According to the present invention, even when a line-type end face thermal head is used, it is possible to perform thermal transfer recording which is excellent in recorded image quality and less likely to cause pressure contact contamination. In particular, the peel strength of the transfer layer at 25 ° C. is 120 g.
By using a thermal transfer recording medium having a transfer layer density of not less than / cm and a glossiness of the transfer layer surface of not more than 70%, thermal transfer recording excellent in recorded image quality and prevention of pressure contact stain can be performed.

[Brief description of the drawings]

FIG. 1 is a schematic explanatory view showing a method for measuring the adhesion between a thermal transfer ink layer and a recording medium.

FIG. 2 is a schematic explanatory view showing a method for measuring the shear strength of the thermal transfer ink layer and the peel strength of the thermal transfer ink layer.

FIG. 3 is a schematic explanatory view showing pressure contact between a thermal transfer recording medium and a recording medium when a conventional thermal head is used and when a line-type end face thermal head is used.

[Explanation of symbols]

REFERENCE SIGNS LIST 1 support base 2 recording medium 3 thermal transfer recording medium 4 rubber plate 5 pressure plate 6 weight 7 support 8 thermal transfer ink layer 9 adhesive tape 10 constant temperature plate 11 pulling direction 20 line type end face thermal head 201 heating element section 40 conventional thermal head 401 Heating element unit 50 Platen roll A Distance from application of heat to thermal head to peeling off of thermal transfer recording medium and recording medium

Claims (9)

[Claims] 1. A thermal transfer recording medium having a thermal transfer ink layer on a support is brought into close contact with a recording medium, and the thermal transfer ink layer is selectively heated by a line-type end face thermal head in accordance with an image signal. In a thermal transfer recording method in which a medium and a recording medium are peeled off and a heat-transfer ink layer melted or softened on an image is transferred onto the recording medium, the transfer layer has a peel strength at 25 ° C. of 120 g / cm or more. And a thermal transfer recording method, wherein the glossiness of the surface of the transfer layer is 70% or less. 2. A thermal transfer recording medium having a thermal transfer ink layer on a support is brought into close contact with a recording medium, and the thermal transfer ink layer is selectively heated by a line-type end face thermal head in accordance with an image signal. And the recording medium are peeled off, and the thermal transfer ink layer melted or softened on the image is transferred onto the recording medium, the peel strength at 25 ° C. of the transfer layer is 120 g / cm or more and A thermal transfer recording medium, wherein the glossiness of the surface of the transfer layer is 70% or less. 3. The thermal transfer recording medium, wherein a thermal transfer ink layer is provided in contact with a surface of the support, and a thermoplastic resin provided on the first ink layer containing a resin as a main component; The thermal transfer recording medium according to claim 2, comprising an uppermost ink layer containing a heat-fusible substance and a colorant. 4. The thermal transfer recording according to claim 3, wherein the resin in the first ink layer is at least one of a polyester resin, a polyvinyl acetal resin, a polyvinyl butyral resin, and a vinyl chloride-vinyl acetate copolymer. Medium. 5. The thermal transfer recording medium according to claim 4, wherein a glass transition temperature of the polyester resin in the first ink layer is 30 ° C. or less. 6. In the thermal transfer recording medium, a release layer mainly composed of a thermally fusible substance and a resin, wherein the thermally fusible ink layer is provided in contact with the surface of the support, and a thermal layer provided on the release layer. 3. The thermal transfer recording medium according to claim 2, comprising an ink layer containing a plastic resin, a heat-fusible substance, and a colorant. 7. The thermal transfer recording medium according to claim 6, wherein the resin in the release layer is at least one of a polyester resin, a polyvinyl acetal resin, a polyvinyl butyral resin, and a vinyl chloride vinyl acetate copolymer. . 8. The thermal transfer recording medium according to claim 7, wherein a glass transition temperature of the polyester resin in the release layer is 30 ° C. or less. 9. A coating solution obtained by mixing a resin melt and a hot melt material in which a powdery heat melt material is mechanically dispersed in a solvent is coated on a support and dried. Item 9. The method for producing a thermal transfer recording medium according to any one of Items 2 to 8.