JP5439798B2 - Thermal transfer sheet - Google Patents

Description

  The present invention relates to a thermal transfer sheet that can be used in a high-speed printer based on a thermal transfer system, and more particularly to a thermal transfer sheet having a plurality of thermal transfer layers provided so as not to overlap in the longitudinal direction.

  In general, a thermal transfer sheet is called an thermal ribbon and is an ink ribbon used in a thermal transfer type printer. A thermal transfer layer is formed on one surface of a substrate, and a backcoat layer (heat resistant layer) is formed on the other surface of the substrate. (Sliding layer). Here, the thermal transfer layer is a layer of ink that is sublimated (sublimation transfer method) or melted (melt transfer method) by the heat generated in the thermal head of the printer and transferred to the transfer target side. .

  At present, the thermal transfer system is widely used for self-printing of digital cameras, cards such as identification cards, amusement output products, etc. because various images can be easily formed in full color along with the enhancement of functions of the printer. Along with the diversification of such applications, there is a growing demand for smaller size, higher speed, lower cost, and durability for the printed material obtained. In recent years, durability has been given to the printed material on the same side of the base sheet. Thermal transfer sheets having a plurality of thermal transfer layers provided with a protective layer and the like that do not overlap with other thermal transfer layers have become quite popular.

  Using a thermal transfer sheet with multiple thermal transfer layers reduces the space occupied by the thermal transfer sheet in the printer compared to using a thermal transfer sheet for each thermal transfer layer, and a protective layer as a layer of the thermal transfer layer. By providing, durability to a printed matter can be provided. On the other hand, with regard to speeding up and cost reduction, although there are some proposals for materials constituting the thermal transfer layer, base sheet, and heat-resistant slip layer, for example, as one of cost reduction, the non-printing area of the thermal transfer sheet Has been proposed, but it is only related to speeding up and cost reduction, and in the case of cost reduction in which the non-printing area of the thermal transfer sheet is reduced as much as possible, By cutting the ears, it becomes an obstacle to speeding up. In addition, in the thermal transfer sheet provided with a plurality of thermal transfer layers having different film thicknesses so as not to overlap one of the base sheet, the difference in dynamic friction coefficient between each thermal transfer layer and the heat-resistant slipping layer during winding and unwinding The resulting distortion and wrinkles are obstacles to speeding up, and there is a demand for a thermal transfer sheet that sufficiently satisfies the market demand.

  In response to such a request, Patent Document 1 discloses a friction coefficient of the image receiving layer surface of the transfer sheet, a friction coefficient of the back surface of the transfer sheet, a friction coefficient of the color surface of the thermal transfer sheet, a friction coefficient of the back surface of the thermal transfer sheet, and the heat transfer sheet. A thermal transfer sheet is disclosed in which the coefficient of friction between the image receiving layer surface and the color material layer of the thermal transfer sheet is defined within a specific numerical range. The purpose of this is to stabilize the running of the sheet when performing thermal transfer with a printer, and to obtain a thermal transfer image free from deviation.

  Patent Document 2 relates to a so-called n-times mode recording method in which the conveyance speed of the thermal transfer sheet is slower than the conveyance speed of the transfer sheet superimposed thereon, but at a specific temperature of the thermal transfer sheet and the transfer sheet. A sublimation type thermal transfer body and a sublimation type thermal transfer image receiving body in which the difference in the dynamic friction coefficient is defined within a specific range are disclosed. This improves the frictional force due to the difference in speed between the transfer layer surface and the image receiving layer surface of the thermal transfer sheet, and poor running and sticking due to resin fusion due to heating when trying to record multiple times peculiar to the n-fold mode recording method. To do.

Further, Patent Document 3 discloses a sublimation in which a difference in dynamic friction coefficient for each image-receiving sheet between a region including a layer containing a colorant and a region including a layer not including a colorant is defined in a specific range. A mold thermal transfer member is disclosed. This is to improve abnormal images and poor conveyance due to wrinkling, fusing and sticking at the time of reheating the image peculiar to the n-fold mode recording method, as in Patent Document 2.
JP-A 63-236690 JP 2000-168247 A JP-A-11-78256

  In the above-described conventional method, the present inventors have intended a thermal transfer sheet that has a high speed in recent years and a plurality of color material layers of the thermal transfer sheet so that the color material layers do not overlap with each other. It is difficult to get. The method of Patent Document 1 is insufficient for providing a thermal transfer sheet that stabilizes running when there is a plurality of recent high speed and color material layers of the thermal transfer sheet so that they do not overlap and the film thicknesses are different. . In addition, the methods of Patent Documents 2 and 3 all improve the running failure due to the fusing characteristic of the n-fold mode recording method, and are insufficient for providing a thermal transfer sheet that stabilizes the high-speed running of the printer. .

  The present invention has been made in view of the above-described problems of the prior art. By using a thermal transfer sheet having a plurality of thermal transfer layers, the thermal transfer sheet in the printer can be used as compared with the case where a thermal transfer sheet is used for each thermal transfer layer. The space occupied by can be reduced in size, and by providing a protective layer as a layer of the thermal transfer layer, durability can be imparted to the printed matter. Providing a thermal transfer sheet that stabilizes high-speed running in the printer by preventing distortion and wrinkles due to the difference in the dynamic friction coefficient between the thermal transfer layer and the heat-resistant slipping layer, and as a result, minimizes the non-printing area. The purpose is to do.

The invention according to claim 1 of the present invention includes a base sheet, a first thermal transfer layer, a second thermal transfer layer, a third thermal transfer layer, and a first thermal transfer layer provided so as not to overlap with the same side of the base sheet . 4 and a heat-resistant slipping layer provided on a surface opposite to the first thermal transfer layer of the base sheet, wherein the first thermal transfer layer is the second thermal transfer layer. The second thermal transfer layer is thicker than the third thermal transfer layer, and the third thermal transfer layer is thicker than the fourth thermal transfer layer. the dynamic friction coefficient between the heat-resistant lubricating layer was measured according to JISK7125 first thermal transfer layer, the second greater than the thermal transfer layer, the second thermal transfer layer, than the third thermal transfer layer The third thermal transfer layer is larger than the fourth thermal transfer layer. This is a thermal transfer sheet.

  The invention according to claim 2 of the present invention is the thermal transfer sheet according to claim 1, wherein the first thermal transfer layer includes an ultraviolet absorber and true spherical particles.

In the invention according to claim 3 of the present invention, the second thermal transfer layer, the third thermal transfer layer, and the fourth thermal transfer layer are formed of a layer containing any one of a cyan dye, a magenta dye, and a yellow dye. The thermal transfer sheet according to claim 1, wherein the thermal transfer sheet is selected.

The invention according to claim 4 of the present invention is the thermal transfer sheet according to claim 1, wherein the second thermal transfer layer includes a hydroxyl group-containing resin.

  By using the thermal transfer sheet of the present invention, the space occupied by the thermal transfer sheet in the printer is reduced compared to the case where a thermal transfer sheet is used for each thermal transfer layer, and a protective layer is provided as one layer of the thermal transfer layer. It is possible to impart durability to the printed material, and to prevent the distortion and wrinkles due to the difference in the dynamic friction coefficient between the thermal transfer layer and the heat-resistant slipping layer having different film thicknesses for speeding up and cost reduction. As a result, it is possible to obtain a thermal transfer sheet that can stabilize high-speed running in the printer and, as a result, can minimize the non-printing area.

  Below, the thermal transfer sheet of this invention is demonstrated with reference to drawings based on one Embodiment.

  As shown in FIG. 1, the thermal transfer sheet (10) has a thermal transfer ink layer (12) composed of three colors of yellow (Y), magenta (M), and cyan (C) on one surface of the base sheet (11). ), A heat transferable protective layer (14) is provided on the other surface of the substrate (11) in the surface order so that the thermal transferable protective layer (13) does not overlap in the longitudinal direction.

  First, since the base sheet is required to have heat resistance and strength that is not softened and deformed by heat pressure in thermal transfer, for example, polyethylene terephthalate, polyethylene naphthalate, polypropylene, cellophane, acetate, polycarbonate, polysulfone, polyimide, polyvinyl alcohol, It can be used as a composite of synthetic resin films such as aromatic polyamide, aramid, and polystyrene, and papers such as condenser paper and paraffin paper, either alone or in combination. In view of the surface and the like, a polyethylene terephthalate film is preferable. Further, the thickness can be in the range of 2 to 50 μm in consideration of operability and workability, but in consideration of handling properties such as transfer suitability and workability, the thickness is about 2 to 12 μm. preferable.

  Next, the thermal transfer ink layer in the thermal transfer sheet includes a sublimation thermal transfer layer composed of a heat sublimable dye and a binder, and a molten thermal transfer layer composed of a dye and / or a pigment and a binder.

  The ink for forming the sublimation heat transfer layer is prepared by blending, for example, a heat sublimation dye, a binder, a solvent, and the like, and an appropriate amount of ink applied to this transfer layer is about 1 μm (dry thickness).

  The ink for forming the thermal transfer layer is prepared, for example, by blending a dye and / or pigment, a binder, a solvent, etc., and the coating amount in this case is suitably about 0.5 to 1 μm (dry thickness). .

A sublimation disperse dye is preferable as the heat sublimation dye used in the ink for forming a sublimation heat transfer layer. For example, as a yellow component, solvent yellow 56, 16, 30,
93, 33, Disperse Yellow 201, 231, 33, and the like. Examples of the magenta component include C.I. I. Disperse thread 60, C.I. I. Disperse violet 26, C.I. I. Solvent Red 27, or C.I. I. Solvent Red 19 etc. are mentioned. As the cyan component, C.I. I. Disperse Blue 354, C.I. I. Solvent Blue 63, C.I. I. Solvent Blue 36, or C.I. I. Disperse Blue 24 and the like. As the ink dye, it is common to perform color matching by combining the above dyes.

  The binder used in the ink for forming the sublimation heat transfer layer is not particularly limited, but cellulose resins such as ethyl cellulose, hydroxyethyl cellulose, ethyl hydroxy cellulose, hydroxypropyl cellulose, methyl cellulose, and cellulose acetate, polyvinyl alcohol, and polyacetic acid Examples thereof include vinyl resins such as vinyl, polyvinyl butyral, polyvinyl acetal, polyvinyl pyrrolidone, and polyacrylamide, polyester resins, styrene-acrylonitrile copolymer resins, and phenoxy resins. Among these, polyvinyl butyral and polyvinyl acetal resins containing a hydroxyl group that can be cross-linked by isocyanate or the like are preferable.

  Here, the ratio of the dye to the binder in the sublimation thermal transfer layer forming ink layer is preferably from dye / binder = 10/100 to 300/100. This is because if the dye / binder ratio is less than 10/100, the amount of dye is too small and the color development sensitivity is insufficient, and a good thermal transfer image cannot be obtained, and if this ratio exceeds 300/100, the binder This is because the solubility of the dye in the ink is extremely lowered, and the storage stability of the ink layer is deteriorated when the thermal transfer sheet is formed, and the dye is likely to be precipitated.

  The dyes used in the ink for forming the thermal transfer layer include diarylmethane, triarylmethane, thiazole, methine, azomethane, xanthene, axazine, thiazine, azine, acridine, azo, and spirodipyran. Commonly used thermal transfer dyes such as those based on isodolin, spiropyrans, fluorans, rhodamines, and anthraquinones can be widely used. As the pigment, known organic pigments and inorganic pigments can be used. For example, carbon black, azo series, phthalocyanine series, quinacridone series, thioindigo series, anthraquinone series, isoindolinone series, etc. Pigments.

  The binder used for the ink for forming the thermal transfer layer is not particularly limited except for the thermal melting property. For example, styrene resins such as polystyrene and poly α-methylstyrene, polymethyl methacrylate, poly Acrylic resins such as ethyl acrylate, polyvinyl chloride, polyvinyl acetate, vinyl chloride-vinyl acetate copolymers, vinyl resins such as polyvinyl butyral and polyvinyl acetal, polyester resins, polyamide resins, epoxy resins, polyurethane resins, petroleum Resin, ionomer, synthetic resin such as ethylene-acrylic acid copolymer, ethylene-acrylic acid ester copolymer, cellulose derivatives such as nitrocellulose, ethyl cellulose, cellulose acetate propionate, rosin, rosin modified maleic acid resin, ester gum , Li isobutylene rubber, butyl rubber, styrene - butadiene rubber, butadiene - acrylonitrile rubber, derivatives of natural resins and synthetic rubber polychlorinated olefins such as carnauba wax, waxes such as paraffin wax. Among these, polyester and epoxy resin are preferable.

  Here, the ratio of the dye and / or pigment (hereinafter sometimes referred to as the colorant component) and the binder in the ink layer for forming the melt thermal transfer layer is as follows: Colorant component / binder = 5/100 to 200/100 Is preferred. This is because when the ratio of the colorant / binder is less than 5/100, the colorant is too small to obtain a good thermal transfer image, and when this ratio exceeds 200/100, the molten thermal transfer layer is aggregated. This is because the storage stability of the ink layer is deteriorated when the thermal transfer sheet is formed because the force is extremely reduced.

  Next, as the thermal transferable protective layer in the thermal transfer sheet, durability from an ultraviolet ray or the like to an image formed on the transferred object by the thermal transferable ink layer is required, and at the same time, the transferred object is processed by a process called a thermal transfer method. Since it is necessary to be formed on the adhesive layer, in addition to adjusting the slipperiness of the surface of the protective layer, the adhesive layer having both the original performance as a protective layer such as ultraviolet absorption and the adhesiveness to the transferred material, In general, the lower layer is formed of a laminate of a plurality of layers such as a release layer for easily peeling from a substrate during thermal transfer.

  The adhesive layer forming ink for forming the heat transferable protective layer is prepared by blending, for example, functional additives such as slipperiness and ultraviolet absorber, a binder, a solvent, and the like. About 5 to 5 μm (dry thickness) is appropriate.

  Examples of functional additives used in inks for forming adhesive layers include calcium carbonate, kaolin, talc, silicone powder, calcium sulfate, barium sulfate, titanium dioxide, zinc oxide, satin white, zinc carbonate, magnesium carbonate, aluminum silicate , Calcium silicate, magnesium silicate, silica, colloidal silica, colloidal alumina, pseudoboehmite, aluminum hydroxide, alumina, lithopone, zeolite, hydrohalosite, magnesium hydroxide and other inorganic fillers, acrylic plastic pigment, styrene plastic pigment, Examples include particles represented by organic fillers such as microcapsules, urea resins, and melamine resins. Among them, a spherical shape such as silicone powder uniformly adjusts the slipperiness of the protective layer surface. In that it can be suitable. Furthermore, benzophenone, benzotriazole, benzoate, UV absorbers typified by triazines, light stabilizers typified by hindered amines, antioxidants typified by hindered phenols, fluorescent whitening agents, antistatic agents, etc. Can be mentioned.

  In addition, the binder is not particularly limited except for heat melting property. For example, styrene resins such as polystyrene and poly α-methylstyrene, acrylic resins such as polymethyl methacrylate and polyethyl acrylate. Resin, polyvinyl chloride, polyvinyl acetate, vinyl chloride-vinyl acetate copolymer, polyvinyl resins such as polyvinyl butyral, polyvinyl acetal, polyester resin, polyamide resin, epoxy resin, polyurethane resin, petroleum resin, ionomer, ethylene-acrylic Synthetic resins such as acid copolymers, ethylene-acrylic acid ester copolymers, cellulose derivatives such as nitrocellulose, ethyl cellulose, cellulose acetate propionate, rosin, rosin-modified maleic acid resin, ester gum, polyisobutylene rubber, butyl rubber , Styrene - acrylonitrile rubbers, natural resins and derivatives of synthetic rubber polychlorinated olefins such as carnauba wax, waxes such as paraffin wax - butadiene rubber, butadiene. Among these, acrylic resins, polyester resins, and epoxy resins are preferable.

  The release layer forming ink for forming the protective layer is prepared by blending, for example, a functional additive imparting releasability and slipperiness, a binder, a solvent, and the like. About 3 to 3 μm (dry thickness) is appropriate.

  Examples of functional additives used in the ink for forming the release layer include silicone oil, release agents typified by phosphate esters, waxes, slip agents typified by resin fillers, ultraviolet absorbers, and light stabilizers. , Antioxidants, fluorescent brighteners, antistatic agents and the like. In addition, the binder is not particularly limited except for heat melting property. For example, styrene resins such as polystyrene and poly α-methylstyrene, acrylic resins such as polymethyl methacrylate and polyethyl acrylate. Resin, polyvinyl chloride, polyvinyl acetate, vinyl chloride-vinyl acetate copolymer, polyvinyl resins such as polyvinyl butyral, polyvinyl acetal, polyester resin, polyamide resin, epoxy resin, polyurethane resin, petroleum resin, ionomer, ethylene-acrylic Synthetic resins such as acid copolymers, ethylene-acrylic acid ester copolymers, cellulose derivatives such as nitrocellulose, ethyl cellulose, cellulose acetate propionate, rosin, rosin-modified maleic acid resin, ester gum, polyisobutylene rubber, butyl rubber , Styrene - acrylonitrile rubbers, natural resins and derivatives of synthetic rubber polychlorinated olefins such as carnauba wax, waxes such as paraffin wax - butadiene rubber, butadiene. Among these, acrylic resins and cellulose derivatives are preferable.

  Next, as the heat-resistant slip layer in the thermal transfer sheet, in addition to the performance required for the thermal transfer process such as prevention of fusion between the thermal transfer sheet and the thermal head or protection of the thermal transfer sheet itself against the heat from the thermal head. In the present invention, it is necessary to adjust the dynamic friction coefficient with a plurality of thermal transfer layers having different film thicknesses so as not to overlap.

  The heat-resistant slip layer forming ink is prepared by blending, for example, a functional additive that adjusts releasability, slipperiness, and surface properties, a binder, a curing agent, a solvent, and the like. The amount is suitably about 0.1 to 2 μm (dry thickness).

  As an example of the heat-resistant slipping layer, examples of the binder include synthetic resins such as acrylic, polyester, polyurethane, polyacetal, polyamide, and polyimide. Examples of the functional additive include stearates such as zinc stearate. And phosphoric acid esters such as polyoxyalkylene alkyl ethers, silicone oils such as amino-modified silicone oils, and particles such as silica and talc. Examples of the curing agent include 2,6-tolylene diisocyanate. Mention may be made of isocyanates.

  The thermal transfer sheet can be easily obtained by applying and forming each layer forming ink on each base sheet by a known method such as gravure coating and slot coating.

  Specific examples of the present invention will be described below.

First, materials used in the examples and comparative examples of the present invention are shown below. In the text, “part” is based on mass unless otherwise specified.
<Base material sheet>
Polyester film: Thickness 4.5μm
<Yellow ink for thermal transfer layer formation>
C. I. Solvent Yellow 93 3.0 parts C.I. I. Solvent Yellow 16 1.0 part Polyvinyl butyral resin 4.2 part Silicone modified resin 0.6 part 2,6-tolylene diisocyanate 0.2 part Tetrahydrofuran 60.0 part Methyl ethyl ketone 31.0 part <Magenta ink for thermal transfer layer formation>
C. I. Disperse thread 60 1.5 parts C.I. I. Disperse Violet 26 1.5 parts Polyvinyl butyral resin 4.0 parts Silicone-modified resin 0.8 part 2,6-tolylene diisocyanate 0.2 part Tetrahydrofuran 60.0 parts Methyl ethyl ketone 31.0 parts <Cyan ink for thermal transfer layer formation -1>
C. I. Solvent Blue 63 1.5 parts C.I. I. Solvent Blue 36 1.5 parts Polyvinyl butyral resin 3.8 parts Silicone modified resin 1.0 part 2,6-tolylene diisocyanate 0.2 part Tetrahydrofuran 60.0 parts Methyl ethyl ketone 31.0 parts <Cyan ink for thermal transfer layer formation- 2>
C. I. Solvent Blue 63 1.5 parts C.I. I. Solvent Blue 36 1.5 parts Polyvinyl butyral resin 4.6 parts Silicone-modified resin 0.2 parts 2,6-tolylene diisocyanate 0.2 parts Tetrahydrofuran 60.0 parts Methyl ethyl ketone 31.0 parts <Ink for release layer formation>
Acrylic resin 18.0 parts Polyester resin 1.0 part Polyethylene powder 1.0 part Toluene 40.0 parts Methyl ethyl ketone 40.0 parts <Ink for forming adhesive layer-1>
Acrylic resin 10.0 parts Polyester resin 10.0 parts Epoxy resin 5.0 parts Toluene 35.0 parts Methyl ethyl ketone 40.0 parts <Ink for forming adhesive layer-2>
Acrylic resin 10.0 parts Polyester resin 3.5 parts Epoxy resin 3.5 parts Benzophenone UV absorber 7.5 parts Silicone powder 0.5 parts Toluene 35.0 parts Methyl ethyl ketone 40.0 parts <Adhesive layer forming ink- 3>
Acrylic resin 10.0 parts Polyester resin 3.7 parts Epoxy resin 3.7 parts Benzophenone UV absorber 7.5 parts Silicone powder 0.1 parts Toluene 35.0 parts Methyl ethyl ketone 40.0 parts <Ink for forming adhesive layer- 4>
Acrylic resin 10.0 parts Polyester resin 10.0 parts Epoxy resin 4.0 parts Epoxy-modified silicone oil 1.0 part Toluene 35.0 parts Methyl ethyl ketone 40.0 parts <Ink for forming a heat resistant slipping layer-1>
Acrylic polyol resin 15.0 parts Zinc stearate 1.5 parts Polyoxyalkylene alkyl ether 1.5 parts Talc 1.0 parts 2,6-tolylene diisocyanate 5.0 parts Toluene 50.0 parts Methyl ethyl ketone 20.0 parts Acetic acid 6.0 parts of ethyl <ink-2 for forming heat resistant slipping layer>
Acrylic polyol resin 15.0 parts Zinc stearate 2.5 parts Amino modified silicone oil 1.0 part Silicone powder 0.5 parts 2,6-tolylene diisocyanate 5.0 parts Toluene 50.0 parts Methyl ethyl ketone 20.0 parts Acetic acid 6.0 parts of <ethyl base material>
Foamed polyester film: 188μm thick
<Ink for forming image receiving layer for thermal transfer>
Vinyl chloride-vinyl acetate-vinyl alcohol copolymer 19.5 parts Amino-modified silicone oil 0.5 part Toluene 40.0 parts Methyl ethyl ketone 40.0 parts <Preparation of base sheet with heat-resistant slip layer of thermal transfer sheet>
By using the gravure coating method, a heat resistant slipping layer is formed with a dry thickness of 0.9 μm on one surface of the base sheet using the heat resistant slipping layer forming ink-1 or 2, and then aged at 40 ° C. for 5 days. Thus, a base sheet A with a heat resistant slipping layer using the heat resistant slipping layer forming ink-1 and a base sheet B with a heat resistant slipping layer using the heat resistant slipping layer forming ink-2 are prepared. did.
<Preparation of transfer object>
Using a gravure coating method, a thermal transfer image-receiving layer is formed on one surface of a transfer substrate using a thermal transfer image-receiving layer forming ink with a dry thickness of 5.0 μm, thereby producing a transfer object for thermal transfer. did.

<Example 1>
The thermal transfer layer 1 uses a release layer forming ink to form a release layer having a dry thickness of 0 so that the heat transfer layer 1 does not overlap the surface of the base sheet A in the longitudinal direction by the gravure coating method. After forming at a thickness of 0.5 μm, the adhesive layer was formed on the release layer using the adhesive layer forming ink-1 to a dry thickness of 1.5 μm to form a protective layer having a total thickness of 2.0 μm. As the thermal transfer layer 2, the thermal transfer sheet of Example 1 including the thermal transfer layer 1 and the thermal transfer layer 2 was formed by forming a thermal transfer layer having a dry thickness of 0.7 μm using cyan ink-1 for thermal transfer layer formation.

<Example 2>
The thermal transfer layer 1 uses a release layer forming ink to form a release layer having a dry thickness of 0 so that the heat transfer layer 1 does not overlap the surface of the base sheet A in the longitudinal direction by the gravure coating method. After forming at a thickness of 0.5 μm, the adhesive layer was formed on the release layer using the adhesive layer forming ink-2 to a dry thickness of 1.5 μm to form a protective layer having a total thickness of 2.0 μm. As the thermal transfer layer 2, a thermal transfer layer of Example 2 including the thermal transfer layer 1 and the thermal transfer layer 2 was produced by forming a thermal transfer layer having a dry thickness of 0.8 μm using the thermal transfer layer forming magenta ink-1.

<Example 3>
The thermal transfer layer 1 uses a release layer forming ink to dry the release layer to a thickness of 0.5 μm so that it does not sequentially overlap the heat resistant slipping layer non-formation surface of the base sheet A by the gravure coating method. After that, the adhesive layer was formed on the release layer using the adhesive layer forming ink-4 with a dry thickness of 1.5 μm to form a protective layer having a total thickness of 2.0 μm. As the thermal transfer layer 2, a thermal transfer sheet of Example 3 including the thermal transfer layer 1 and the thermal transfer layer 2 was produced by forming a thermal transfer layer having a dry thickness of 0.9 μm using the yellow ink-1 for thermal transfer layer formation.

<Example 4>
The thermal transfer layer 1 uses a release layer forming ink to form a release layer having a dry thickness of 0 so that the heat transfer layer 1 does not overlap the surface of the base sheet B in the longitudinal direction by the gravure coating method. After forming at a thickness of 0.5 μm, the adhesive layer was formed on the release layer using the adhesive layer forming ink-1 to a dry thickness of 1.5 μm to form a protective layer having a total thickness of 2.0 μm. As the thermal transfer layer 2, a thermal transfer sheet of Example 4 including the thermal transfer layer 1 and the thermal transfer layer 2 was formed by forming a thermal transfer layer having a dry thickness of 0.7 μm using cyan ink-1 for thermal transfer layer formation.

<Example 5>
The thermal transfer layer 1 uses a release layer forming ink to form a release layer having a dry thickness of 0 so that the heat transfer layer 1 does not overlap the surface of the base sheet A in the longitudinal direction by the gravure coating method. After forming at a thickness of 0.5 μm, the adhesive layer was formed on the release layer using the adhesive layer forming ink-3 with a dry thickness of 1.5 μm to form a protective layer having a total thickness of 2.0 μm. The thermal transfer layer 2 is formed using a thermal transfer layer forming yellow ink-1 to form a thermal transfer layer with a dry thickness of 0.9 μm, and the thermal transfer layer 3 is formed using a thermal transfer layer forming magenta ink-1 with a dry thickness of 0. An 8 μm thermal transfer layer is formed, and the thermal transfer layer 4 is formed using a thermal transfer layer forming cyan ink-1 to form a thermal transfer layer having a dry thickness of 0.7 μm, whereby the thermal transfer layer 1, the thermal transfer layer 2, and the thermal transfer layer 3 are formed. A thermal transfer sheet of Example 5 comprising the thermal transfer layer 4 was produced.

<Comparative Example 1>
The thermal transfer layer 1 uses a release layer forming ink to form a release layer having a dry thickness of 0 so that the heat transfer layer 1 does not overlap the surface of the base sheet A in the longitudinal direction by the gravure coating method. After forming at a thickness of 3 μm, the adhesive layer was formed on the release layer using the adhesive layer forming ink-1 to a dry thickness of 0.7 μm to form a protective layer having a total thickness of 1.0 μm. As the thermal transfer layer 2, a thermal transfer sheet of Comparative Example 1 including the thermal transfer layer 1 and the thermal transfer layer 2 was produced by forming a thermal transfer layer having a dry thickness of 1.2 μm using cyan ink-1 for thermal transfer layer formation.

<Comparative example 2>
The thermal transfer layer 1 uses a release layer forming ink to form a release layer having a dry thickness of 0 so that the heat transfer layer 1 does not overlap the surface of the base sheet B in the longitudinal direction by the gravure coating method. After forming at a thickness of 0.5 μm, the adhesive layer was formed on the release layer using the adhesive layer forming ink-2 to a dry thickness of 1.5 μm to form a protective layer having a total thickness of 2.0 μm. As the thermal transfer layer 2, a thermal transfer layer of Comparative Example 2 including the thermal transfer layer 1 and the thermal transfer layer 2 was prepared by forming a thermal transfer layer having a dry thickness of 0.7 μm using cyan ink-2 for thermal transfer layer formation.

<Comparative Example 3>
The thermal transfer layer 1 uses a release layer forming ink to form a release layer having a dry thickness of 0 so that the heat transfer layer 1 does not overlap the surface of the base sheet A in the longitudinal direction by the gravure coating method. .5
After forming at μm, the adhesive layer was formed on the release layer using the adhesive layer forming ink-3 to a dry thickness of 1.5 μm to form a protective layer having a total thickness of 2.0 μm. The thermal transfer layer 2 is formed using a thermal transfer layer forming yellow ink-1 to form a thermal transfer layer having a dry thickness of 0.7 μm, and the thermal transfer layer 3 is formed using a thermal transfer layer forming magenta ink-1 having a dry thickness of 0. An 8 μm thermal transfer layer is formed, and the thermal transfer layer 4 is formed by using the thermal transfer layer forming cyan ink-1 to form a thermal transfer layer having a dry thickness of 0.9 μm, so that the thermal transfer layer 1, the thermal transfer layer 2, and the thermal transfer layer 3 are formed. A thermal transfer sheet of Comparative Example 3 composed of the thermal transfer layer 4 was produced.

<Comparative Example 4>
The thermal transfer layer 1 uses a release layer forming ink to form a release layer having a dry thickness of 0 so that the heat transfer layer 1 does not overlap the surface of the base sheet B in the longitudinal direction by the gravure coating method. After forming with a thickness of 0.5 μm, the adhesive layer was formed on the release layer with an adhesive layer forming ink-4 with a dry thickness of 1.5 μm to form a protective layer with a total thickness of 2.0 μm. The thermal transfer layer 2 is formed using a thermal transfer layer forming yellow ink-1 to form a thermal transfer layer with a dry thickness of 0.9 μm, and the thermal transfer layer 3 is formed using a thermal transfer layer forming magenta ink-1 with a dry thickness of 0. An 8 μm thermal transfer layer is formed, and the thermal transfer layer 4 is formed using a thermal transfer layer forming cyan ink-1 to form a thermal transfer layer having a dry thickness of 0.7 μm, whereby the thermal transfer layer 1, the thermal transfer layer 2, and the thermal transfer layer 3 are formed. A thermal transfer sheet of Comparative Example 4 comprising the thermal transfer layer 4 was produced.

<Measurement of dynamic friction coefficient>
Regarding the thermal transfer sheets of Examples 1 to 5 and Comparative Examples 1 to 4, based on JIS K7125, the coefficient of dynamic friction between the heat-resistant slipping layer of each thermal transfer sheet and each thermal transfer layer was measured by a surface property measuring machine (HEIDON-14D manufactured by HEIDON) Table 1 shows the results of measurement with a contact area of 4000 mm ² , a load of 1.96 N, and a speed of 100 mm / min.

＜熱転写シートのスリット＞
実施例１〜５、比較例１〜４の熱転写シートに関して、副走査線方向実画幅を１００％として、１０５、１１０、１１５％幅にスリット加工を実施した。

<Slit of thermal transfer sheet>
With respect to the thermal transfer sheets of Examples 1 to 5 and Comparative Examples 1 to 4, slit processing was performed to 105, 110, and 115% widths with the actual image width in the sub-scanning line direction being 100%.

<Print evaluation>
With respect to the thermal transfer sheets of Examples 1 to 5 and Comparative Examples 1 to 4, a solid printing was performed for 500 m under the conditions shown in Table 2 using a combination of each slit processed thermal transfer sheet and a transfer target. The results are shown in Table 3. The evaluation of the results in Table 3 is as follows.

○: Good with no problem △: Print defect due to deflection of thermal transfer sheet ×: Printing stopped due to breakage due to deflection of thermal transfer sheet

表３に示す結果から、実施例１〜５の熱転写シートは、非印画部領域を極力少なくした場合にも、印画の際プリンタにおける高速走行が可能なことが解る。なお実施例３の熱転写シートにおいて、高速印画条件、スリット幅１０５％条件下でたわみによる印画皺が確認されているが、破断による印画停止とは印画走行上大きな差と考える。

From the results shown in Table 3, it can be seen that the thermal transfer sheets of Examples 1 to 5 can run at high speed in the printer during printing even when the non-printing area is reduced as much as possible. In the thermal transfer sheet of Example 3, printing defects due to deflection were confirmed under high-speed printing conditions and a slit width of 105%, but printing stop due to breakage is considered to be a large difference in printing running.

  In addition, it can be seen that the thermal transfer sheet of Example 5 has a thermal transfer sheet having three or more thermal transfer layers provided so as not to overlap with each other.

  On the other hand, the thermal transfer sheet of Comparative Example 1 uses the same material as the thermal transfer sheet of Example 1, but the first thermal transfer layer and the second thermal transfer layer have the second thermal transfer layer in terms of film thickness. The first thermal transfer layer has a larger dynamic friction coefficient with respect to the heat resistant slipping layer. In such a case, it can be seen that there is a significant problem with high-speed traveling with the non-printing area reduced as much as possible.

  Further, in the thermal transfer sheet of Comparative Example 2, the first thermal transfer layer and the second thermal transfer layer have a larger film thickness than the first thermal transfer layer, and the dynamic friction coefficient with respect to the heat resistant slipping layer is that of the second thermal transfer layer. Is getting bigger. In such a case, it can be seen that the running itself with the non-printing area reduced as much as possible has a big problem.

  In addition, although the thermal transfer sheet of Comparative Example 3 uses the same material as the thermal transfer sheet of Example 5, the third thermal transfer layer is thicker in the second thermal transfer layer and the third thermal transfer layer. The second thermal transfer layer is larger in the coefficient of dynamic friction with respect to the heat resistant slipping layer, and at the same time, the fourth thermal transfer layer is larger in film thickness in the third thermal transfer layer and the fourth thermal transfer layer. The third thermal transfer layer is larger in the dynamic friction coefficient with respect to the heat resistant slipping layer. In such a case, it can be seen that there is a significant problem with high-speed traveling with the non-printing area reduced as much as possible.

  Further, in the thermal transfer sheet of Comparative Example 4, in the first thermal transfer layer and the second thermal transfer layer, the first thermal transfer layer is larger in film thickness, and the dynamic friction coefficient with respect to the heat resistant slipping layer is the same. At the same time, in the second thermal transfer layer and the third thermal transfer layer, the second thermal transfer layer is larger in film thickness, and the dynamic friction coefficient for the heat resistant slipping layer is the same. In such a case, it can be seen that there is a major problem with high-speed traveling.

The cross-sectional schematic diagram which shows an example of the laminated constitution of the thermal transfer sheet of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Thermal transfer sheet 11 ... Base sheet 12 ... Thermal transfer ink layer 13 ... Thermal transfer protective layer 14 ... Heat-resistant slipping layer

Claims (4)

A base sheet, a first thermal transfer layer, a second thermal transfer layer, a third thermal transfer layer, and a fourth thermal transfer layer provided so as not to overlap with the same side of the base sheet; a thermal transfer sheet comprising a first thermal transfer layer and the opposite heat resistant slipping layer provided on the surface of the first thermal transfer layer, the film thickness is greater than the second thermal transfer layer, the second The thermal transfer layer 2 has a thickness larger than that of the third thermal transfer layer, the third thermal transfer layer has a thickness larger than that of the fourth thermal transfer layer, and the heat-resistant slip measured according to JISK7125. The first thermal transfer layer has a larger coefficient of dynamic friction with the layer than the second thermal transfer layer, the second thermal transfer layer is larger than the third thermal transfer layer, and the third thermal transfer layer is A thermal transfer sheet that is larger than the fourth thermal transfer layer .   The thermal transfer sheet according to claim 1, wherein the first thermal transfer layer includes an ultraviolet absorber and true spherical particles. The said 2nd thermal transfer layer, the said 3rd thermal transfer layer, and the said 4th thermal transfer layer are selected from the layer containing either a cyan dye, a magenta dye, or a yellow dye. The thermal transfer sheet described . The thermal transfer sheet according to claim 1, wherein the second thermal transfer layer includes a hydroxyl group-containing resin.

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