JPH0924680A - Thermal transfer sheet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent a printing ruck from being generated even in the use of a cantilever type printer while excellent printing quality is kept by a method wherein particles of ethylene-vinylacetate copolymer and the other binder constituents are contained in a specific ratio in a surface layer. SOLUTION: For a cantilever type printer, a thermal head 1 is supported with a thermal head supporting part 2. When a sheet to be transferred 3 and a material to be transferred 4 overplap each other between the thermal head 1 and a guide plate 5, they move in a flow direction, and printing is carried out. In the thermal transfer sheet wherein a hot melt ink layer and a surface layer are laminated in this order on one side surface of a base material film, the surface layer contains a grain of ethylene-vinylacetate copolymer and the other binder constituents. Further, the other binder constituents and the particle of ethylene-vinylacetate copolymer are contained at a ratio of 100 to 0.5-2.5. The material to be transferred 4 and the thermal transfer sheet 3 are made difficult to slide, meandering of the thermal transfer sheet 3 is prevented against the material to be transferred 4, and printing ruck is prevented from being generated.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermal transfer sheet having a heat-fusible ink layer, and more particularly, to a small serial printer to which a thermal head is easily attached, for example, a single-support type portable type. The present invention relates to a thermal transfer sheet used in a printer.

[0002]

2. Description of the Related Art Conventionally, as a thermal transfer recording medium used in a thermal printer, a facsimile or the like, a thermal transfer sheet having a heat-fusible ink layer provided on one surface of a base film has been used. A conventional thermal transfer sheet uses a base material film such as capacitor paper or paraffin paper having a thickness of about 10 to 20 μm or a plastic film such as polyester or cellophane having a thickness of about 3 to 20 μm. A heat-meltable ink layer is formed by applying a heat-meltable ink prepared by mixing a wax with a colorant such as a pigment or a dye. Then, from the back side of the substrate film, a predetermined location is heated and pressed by a thermal head to melt the heat fusible ink layer in the location corresponding to the printing portion of the heat fusible ink layer and transfer it to printing paper to print. Is to do.

[0003]

However, in the above-mentioned thermal transfer sheet, in a small serial printer, a thermal head is easily attached, and in particular, a type in which the thermal head is supported only on one of the left and right sides ( When used for a printer of one-sided support type, the printing pressure of the thermal head is different between left and right, which may cause running defects on the thermal transfer sheet, which may cause print wrinkles, print fading or stains. There is a problem that it occurs.

The present invention solves the above problems and, in a small-sized serial printer, a thermal head is easily attached, for example, in a single-support type printer, no thermal wrinkles occur and thermal transfer with good printing quality is achieved. The purpose is to provide a sheet.

[0005]

In order to achieve the above object, the present invention provides a thermal transfer sheet comprising a base film, a heat-fusible ink layer and a surface layer laminated in this order on one surface of the base film, The surface layer contains ethylene-vinyl acetate copolymer particles and other binder components, and the other binder components and ethylene-vinyl acetate copolymer particles are added in an amount of 100 to 0.5 to 2.5. It is characterized in that it is contained in a ratio. Further, a matte layer is provided between the base film and the heat-meltable ink layer. Further, a back layer is provided on the other surface of the base film.

The thermal transfer sheet of the present invention is a thermal transfer sheet obtained by laminating a heat-fusible ink layer and a surface layer on one surface of a substrate film in this order, wherein the surface layer is an ethylene-vinyl acetate copolymer. Ethylene particles and other binder components, and other binder components and ethylene-
Particles of vinyl acetate copolymer, 100 to 0.5-2.5
By making the transfer material and the thermal transfer sheet less likely to slip, the thermal transfer sheet can be prevented from meandering with respect to the transfer object. In addition, the adhesiveness of the transferred ink to the transferred material is improved, and in particular, in a single-support type printer, a thermal transfer sheet with good print quality without print wrinkles can be obtained.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION Next, embodiments of the present invention will be described in detail. The thermal transfer sheet of the present invention comprises a base film, a heat-fusible ink layer formed on one surface of the base film, and a surface layer provided thereon. Also,
In the thermal transfer sheet of the present invention, a matte layer and a back layer may be provided on the other surface of the base film to obtain a matte printed matter between the base film and the heat-fusible ink layer, if necessary. Is.

(Substrate film) As the substrate film used in the thermal transfer sheet of the present invention, the same substrate film as that used in the conventional thermal transfer sheet can be used as it is, and other substrates can also be used. It can be done and is not particularly limited. Specific examples of the preferred substrate film include, for example, polyester, polypropylene, cellophane, polycarbonate, cellulose acetate, polyethylene, polyvinyl chloride, polystyrene, nylon, polyimide, polyvinylidene chloride, polyvinyl alcohol, fluororesin, chlorinated rubber, ionomer and the like. , Plastic paper, condenser paper, paper such as paraffin paper, non-woven fabric, and the like, and may be a base film formed by combining these. The thickness of this substrate film can be appropriately changed depending on the material so that its strength and thermal conductivity are appropriate, but the thickness is preferably, for example, 2
２５25 μm.

(Back surface layer) Further, a back surface layer may be provided on the other surface of the base material in order to prevent the thermal head from sticking and improve the slipperiness. This back surface layer includes a binder resin, a slip agent, a surfactant, inorganic particles,
Those formed by adding organic particles, pigments, etc. are preferably used.

The binder resin used in the back layer is, for example, a cellulose resin such as ethyl cellulose, hydroxyethyl cellulose, hydroxypropyl cellulose, methyl cellulose, cellulose acetate, cellulose acetate butyrate, nitrified cotton, polyvinyl alcohol, polyvinyl acetate, polyvinyl butyral. , Polyvinyl acetal,
Examples include vinyl-based resins such as polyvinylpyrrolidone, acrylic resin, polyacrylamide, acrylonitrile-styrene copolymer, polyester resin, polyurethane resin, silicone-modified or fluorine-modified urethane resin. Among them, it is preferable to use a cross-linking resin using one having several reactive groups, for example, a hydroxyl group, and using a polyisocyanate as a cross-linking agent in combination.

The means for forming the back layer is as described above.
A material obtained by adding a slipping agent, a surfactant, inorganic particles, organic particles, a pigment, and the like to a binder resin is dissolved or dispersed in an appropriate solvent to prepare a coating liquid, and the coating liquid is coated with a gravure coater. Coating and drying are performed by conventional coating means such as a roll coater and a wire bar.

(Mat layer) A mat layer may be provided between the substrate and the heat-fusible ink layer. The reason is as follows. The thermal transfer image generally has a glossy surface on the printed matter and is beautiful, but on the other hand, it may be difficult to read a printed document, so that matte printing may be desirable. At that time, for example, a proposal made by the present applicant (Japanese Patent Application No. 58-2
No. 08306), a liquid in which an inorganic pigment such as silica or calcium carbonate is dispersed in an appropriate solvent using an arbitrary resin as a binder is applied between the base material and the heat-meltable ink layer. The mat layer can be provided by working and drying. The thickness of the mat layer is preferably about 0.1 to 1 μm. If it is less than 0.1 μm, the performance as a mat layer is not sufficient, and if it exceeds 1 μm, a large amount of printing energy is required, which is not preferable.

(Hot-melt ink layer) The hot-melt ink layer is
It is composed of a conventionally known colorant and a binder, and if necessary, various additives such as mineral oil, vegetable oil, higher fatty acid such as stearic acid, plasticizer, thermoplastic resin and filler are added. . Examples of the wax component used as the binder include microcrystalline wax, carnauba wax, and paraffin wax.
Furthermore, various types such as Fischer-Tropsch wax, various low molecular weight polyethylenes, wood wax, beeswax, spermaceti, Ibota wax, wool wax, shellac wax, candelilla wax, petrolactam, polyester wax, partially modified wax, fatty acid ester, fatty acid amide, etc. Is used. Among these, especially the melting point is 50-8
It is preferably 5 ° C. If it is 50 ° C. or lower, there is a problem in storage stability, and if it is 85 ° C. or higher, the sensitivity is insufficient.

As the resin component used as the binder, for example, ethylene-vinyl acetate copolymer, ethylene-acrylic acid ester copolymer, polyethylene, polystyrene, polypropylene, polybutene, petroleum resin, vinyl chloride resin, vinyl chloride-acetic acid. Vinyl copolymer, polyvinyl alcohol, vinylidene chloride resin, methacrylic resin, polyamide, polycarbonate, fluororesin, polyvinyl formal, polyvinyl butyral, acetyl cellulose, nitrocellulose, polyvinyl acetate, polyisobutylene, ethyl cellulose or polyacetal. Particularly, those having a relatively low softening point conventionally used as a heat-sensitive adhesive, for example, a softening point of 50 to 80 ° C. are preferable.

The colorant can be appropriately selected from known organic or inorganic pigments or dyes,
For example, it has a sufficient coloring density, discolors due to light, heat, etc.
Those that do not fade are preferred. Further, it may be a substance that develops color by heating or a substance that develops color when it comes into contact with a component applied to the surface of the transfer-receiving body. Further, the color of the colorant is not limited to cyan, magenta, yellow, and black, and various colors of colorants can be used.

Further, in order to give the heat-meltable ink layer good heat conductivity and heat-melt transferability, a heat-conductive substance may be blended as a filler of the binder. Examples of such a filler include carbonaceous substances such as carbon black, and metals and metal compounds such as aluminum, copper, tin oxide, and molybdenum disulfide.

The hot-melt ink layer is formed by mixing and adjusting the colorant component and the binder component as described above and, if necessary, a solvent component such as water and an organic solvent. The coating liquid is applied by a conventionally known method such as hot melt coating, hot lacquer coating, gravure coating, gravure reverse coating, or roll coating. Also, there is a method of forming using an aqueous or non-aqueous emulsion coating liquid. The thickness of the heat-fusible ink layer should be determined so that the required print density and heat sensitivity can be balanced, and is in the range of 0.1 μm to 30 μm, preferably 1 μm.
It is preferably about m to 20 μm.

(Surface Layer) The surface layer contains particles of an ethylene-vinyl acetate copolymer and other binder components. By making the transfer-receiving material and the thermal transfer sheet less slippery, Prevent the meandering of the thermal transfer sheet,
Further, it also has a function of improving the adhesiveness of the ink to be transferred to the transfer target. The ethylene-vinyl acetate copolymer particles have an average particle size of 0.1 μm.
It is preferably about 10 μm. Further, the molecular weight and the acetic acid degree of the ethylene-vinyl acetate copolymer particles as a resin are not particularly limited, and can be arbitrarily selected as long as they have the average particle diameter described above. .

Examples of other binder components other than the ethylene-vinyl acetate copolymer include carnauba wax, microcrystalline wax, paraffin wax, rice wax, polyethylene wax, and the like, and one or two of these resins can be used. A mixture of more than one species is used. The surface layer contains the particles of the ethylene-vinyl acetate copolymer and the other binder component described above, and the other binder component and the particles of the ethylene-vinyl acetate copolymer are 100: 0.5-0.5. It is contained in a ratio of 2.5. The content of the other binder component and the particles of the ethylene-vinyl acetate copolymer is 100, and the content of the particles of the ethylene-vinyl acetate copolymer is 100.
When it is more than 2.5, the transferability to the transfer target is impaired, and the printing quality is deteriorated. When the content of the other binder component and the particles of the ethylene-vinyl acetate copolymer is less than 100: 0.5, the content of the particles of the ethylene-vinyl acetate copolymer is less than 100. The body and the thermal transfer sheet slip, and there is no effect of preventing print wrinkles.

Further, a heat conductive substance may be blended as a filler in order to provide the surface layer with good heat conductivity and heat melting transferability. Examples of such fillers include carbonaceous substances such as carbon black, aluminum, copper,
Examples include metals and metal compounds such as tin oxide and molybdenum disulfide.

The surface layer is formed by a method such as gravure coating, gravure reverse coating or roll coating with an emulsion coating solution in which particles of ethylene-vinyl acetate copolymer and other binder components are dispersed in water or a solvent. Is applied, dried, and then applied. Even if the drying temperature is not lower than the melting point of the particles of the ethylene-vinyl acetate copolymer,
If the particles of the ethylene-vinyl acetate copolymer do not completely melt and the particles remain, the melting point may be slightly higher than the melting point. The thickness of the surface layer is about 0.04 μm to 1.0 μm, preferably about 0.1 μm to 1.0 μm. Needless to say, the thermal transfer sheet of the present invention can be applied to color printing, and a multicolor thermal transfer sheet is also included in the scope of the present invention. Incidentally, the thermal transfer sheet of the present invention is not limited to the above embodiment of the present invention.

A single-sided type printer in which a thermal head is easily attached, which is a small serial printer, will be described with reference to FIG. In the single-sided type printer, the thermal head 1 is supported by the thermal head support portion 2, and the thermal transfer sheet 3 and the transfer-receiving member 4 are overlapped between the thermal head 1 and the guide plate 5 to form a paper. Has been passed through. However, the surface in contact with the thermal head 1 is the back layer side of the thermal transfer sheet 3. Further, when the thermal transfer sheet 3 and the transfer-receiving body 4 are overlapped with each other, the thermal head 1 moves in the flow direction to perform printing.

[0023]

EXAMPLES Next, the present invention will be further described with reference to Examples and Comparative Examples.
This will be described specifically. In the text, "part" or "%" means
Unless otherwise specified, it is based on weight. (Example 1) As a base film, a film having a thickness of 4.5 μm was used.
On one side of the polyethylene terephthalate film,
The mat layer of the composition is 0.5 μm with a gravure coater.
It is provided with the thickness of. Then, on the mat layer,
Coating solution for hot-melt ink layer of gravure coater
After coating and drying, a 4.2 μm thick heat-meltable ink
Form a layer and then gravure a surface layer of the following composition
Coating and drying with a coater, 0.3 μm thick surface layer
To form In addition, on the other surface of the base film, the following composition
The back layer coating solution is applied by a roll coater and dried.
Then, a back layer having a thickness of 0.1 μm is provided, and the thermal transfer of the present invention is performed.
Prepare a sheet.Coating liquid for matte layer Polyester resin (Toyobo Co., Ltd. Byron 200) 60 parts Carbon black (Mitsubishi Chemical Co., Ltd. diamond black) 40 parts Methyl ethyl ketone 100 parts Toluene 200 parts Coating liquid for hot-melt ink layer Carbon black (Diamond Black manufactured by Mitsubishi Chemical Corporation) 20 parts Carnauba wax 25 parts Paraffin wax 50 parts (SP-0160 manufactured by Nippon Seiro Co., Ltd.) Ethylene-vinyl acetate copolymer 10 parts (Mitsui DuPont Polychemical Co., Ltd. EVAFLEX 200W)Surface layer coating liquid Carnauba wax, microcrystalline wax mixed water dispersion 100 parts (100 parts are solid content converted) Ethylene-vinyl acetate copolymer 1 part (Mitsui Petrochemical Co., Ltd. Chemipearl V-300) Isopropyl alcohol 100 parts Back layer coating liquid Polyvinyl butyral resin 20 parts (Esrec BX-1 manufactured by Sekisui Chemical Co., Ltd.) Talc (Microace L-1 manufactured by ALC Japan) 30 parts Melamine resin fine particles (Eposter S manufactured by Nippon Shokubai Chemical Co., Ltd.) 30 parts Polyisocyanate ( Takeda Pharmaceutical Co., Ltd. Takenate A-3) 40 parts Toluene / methyl ethyl ketone (1/1) 900 parts

(Example 2) A thermal transfer sheet of the present invention is prepared in the same manner as in Example 1, except that the surface layer coating liquid has the following composition. Surface layer coating solution Carnauba wax, microcrystalline wax mixed water dispersion 100 parts (100 parts are converted to solid content) Ethylene-vinyl acetate copolymer 2 parts (Mitsui Petrochemical Co., Ltd. Chemipal V-300) Isopropyl alcohol 100 copies

Comparative Example 1 A thermal transfer sheet of the present invention is prepared in the same manner as in Example 1 except that the surface layer coating liquid has the following composition. Surface layer coating liquid Carnauba wax, microcrystalline wax mixed water dispersion 100 parts (100 parts are solid content converted) Isopropyl alcohol 100 parts

Comparative Example 2 A thermal transfer sheet of the present invention is prepared in the same manner as in Example 1 except that the coating solution for surface layer has the following composition. Surface layer coating liquid Carnauba wax, microcrystalline wax mixed water dispersion 250 parts (100 parts are solid content converted) Ethylene-vinyl acetate copolymer 1 part (Mitsui Petrochemical Co., Ltd. Chemipearl V-300) Isopropyl alcohol 100 copies

Comparative Example 3 A thermal transfer sheet of the present invention is prepared in the same manner as in Example 1 except that the surface layer coating liquid has the following composition. Surface layer coating liquid Carnauba wax, microcrystalline wax mixed water dispersion 100 parts (100 parts are solid content converted) Ethylene-vinyl acetate copolymer 4 parts (Mitsui Petrochemical Co., Ltd. Chemipearl V-300) Isopropyl alcohol 100 copies

Using the thermal transfer sheets of the above Examples and Comparative Examples, solid printing was performed under the following printing conditions, and the state of wrinkles was visually evaluated according to the following criteria, and the results shown in Table 1 were obtained. was gotten. Printing condition Equipment: Serial printer equipped with a single-sided thermal head with a width of 30 mm Printing energy: 0.18 mj / dot Transfer material: Rough paper (Beck smoothness 30 seconds) Wrinkle evaluation method Printing under the above conditions The solid printing portion of the transferred material is evaluated according to the following criteria. ◯: No chipping is visually observed in the solid print portion. X: A chip is visually observed in the solid print portion. (Below margin)

[0029]

[Table 1]

[0030]

As described above, according to the present invention, in the thermal transfer sheet obtained by laminating the heat-meltable ink layer and the surface layer in this order on one surface of the substrate film, the surface layer is
The ethylene-vinyl acetate copolymer particles and the other binder component were contained, and the other binder component and the ethylene-vinyl acetate copolymer particles were mixed with 100: 0.5.
A thermal transfer sheet which is easily attached to a small-sized serial printer by including the thermal head in a ratio of up to 2.5, for example, in a single-support type printer, does not cause print wrinkles and has good print quality. Will be provided.

[0031]

[Brief description of drawings]

FIG. 1 is a single-sided printer that is a type of small serial printer used in the present invention.

[Explanation of symbols]

 1 Thermal Head 2 Thermal Head Support 3 Thermal Transfer Sheet 4 Transfer Target 5 Guide Plate

Claims (3)

[Claims] 1. A thermal transfer sheet comprising a base film, a heat-fusible ink layer and a surface layer laminated in this order on one surface of the base film, wherein the surface layer comprises ethylene-vinyl acetate copolymer particles and other particles. A thermal transfer sheet comprising a binder component and further containing other binder components and particles of an ethylene-vinyl acetate copolymer in a ratio of 100 to 0.5 to 2.5. 2. A thermal transfer sheet comprising a base film and a heat-fusible ink layer and a surface layer laminated in this order on one surface of the base film, and between the base film and the hot-melt ink layer.
The thermal transfer sheet according to claim 1, wherein a mat layer is provided. 3. The thermal transfer sheet according to claim 1, wherein a back layer is provided on the other surface of the base film.