JP2009202393A - Thermal transfer recording medium - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To realize a highly sensitive and smooth transferring under the condition that not shifting of dye, additive or the like, included in the thermal transfer layer of a thermal transfer recording medium, develops, the blocking of the thermal transfer media is prevented from developing, and that the welding of the surface of the thermal transfer layer to the surface of the body to be thermally transferred by heat at its confrontation with the surface of the body to be thermally transferred. <P>SOLUTION: In the thermal transfer recording medium with at least a colorant layer on the support, the colorant layer includes at least a binder and particles under the condition that the whole surfaces of the particles are covered with the binder and, at the same time, some part or the whole of the surface of the colorant layer has an uneven shape. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

The present invention relates to a thermal transfer recording medium having a thermal transfer layer for forming characters or images on a thermal transfer member.

  Conventionally, a sublimation thermal transfer system, a melt thermal transfer system, or the like has been adopted as a system for forming characters or images on a transfer target. For example, in the case of the sublimation type thermal transfer system, the surface of the thermal transfer recording medium provided with a thermal transfer layer containing a dye or a binder on the support, and a coated layer provided with a receiving layer for receiving the dye on another support. Dye in the thermal transfer layer is sublimated by superimposing the receiving layer surface of the thermal transfer body on each other and heating from the surface of the thermal transfer recording medium where the thermal transfer layer is not provided with a thermal head or the like that is temperature controlled by text or image information. The desired character or image is formed by shifting to the receiving layer.

  On the other hand, in the case of the melt-type thermal transfer system, the thermal transfer layer surface of the thermal transfer recording medium provided with a heat-fusible thermal transfer layer containing a pigment or wax on the support, and the thermal transfer provided with a receiving layer on another support. The receiving layer surface of the body is superposed on each other and heated by a thermal head or the like, so that the thermal transfer layer is fused and transferred to the receiving layer to form a desired character or image. Among the above methods, the sublimation thermal transfer method is widely used for monochrome printing such as characters and charts and color printing such as digital camera images or computer graphics images.

  By the way, in the case of the sublimation type thermal transfer system, when the surface of the thermal transfer layer faces the surface of the thermal transfer medium at the time of printing, there is a lack of releasability due to fusion to the surface of the thermal transfer body due to heat, resulting in image disturbance, Often problematic. The thermal transfer recording medium is installed in the printer in the form of a roll wound around a winding shaft, and is held in a state where the surface of the thermal transfer layer and the surface of the thermal transfer recording medium not provided with the thermal transfer layer are in contact with each other. When the time is long or the winding pressure is large, the dye or additive contained in the thermal transfer layer of the thermal transfer recording medium shifts to the surface of the thermal transfer recording medium that is not provided with the thermal transfer layer. The transferred dye or additive causes a problem of fouling the thermal head during thermal transfer. Furthermore, when the thermal transfer recording medium is unwound at the time of printing, the surface of the thermal transfer recording layer and the surface of the thermal transfer recording medium that does not have the thermal transfer layer are blocked, causing a problem in running the thermal transfer recording medium in the printer. There is.

Many methods have been proposed to solve the above problems. For example, in Patent Document 1, the color material layer includes, in addition to the sublimable dye and the binder, ultrafine particles having an average primary particle size of 0.1 μm or less and particles having an average particle size of 0.5 μm or more. By doing so, it has been proposed that no drooling occurs only in the halftone region due to subtraction or scattering of the dye in the portion where energy is not applied and the portion where energy is not applied. In Patent Literature 2, the friction between the thermal transfer layer of the thermal transfer sheet and the receiving layer of the thermal transfer sheet is reduced by adding a solid lubricant in the thermal transfer layer, and the thermal transfer layer is fused to the receiving layer by frictional heat. A method to prevent this is proposed.
According to Patent Document 3, the dye layer contains one or more granular polypropylene waxes having an average particle size of less than 30 μm and a melting point higher than 125 ° C., thereby eliminating and reducing defects on the print, and Proposes a method that can produce sufficient gloss. In Patent Document 4, since the dye layer contains a micropowder type polyethylene wax, the transfer of the dye is not hindered by the particles, and good slipperiness, releasability and storage of the thermal transfer sheet can be achieved with respect to the image receiving sheet. It proposes that sex can be obtained. Further, in Patent Document 5, in a thermal transfer sheet in which a dye layer composed of a dye and a binder is provided on a base film, the dye layer has a particle size of 1.0 μm or less and a particle size of 5 μm or more and is heat-meltable. It has been proposed that the inclusion of fine particles prevents the back layer and the dye layer from blocking, lowering the coating suitability of the coating solution, or preventing the roughness of the image formed during image formation.
JP-A 61-175090 JP-A 63-27291 JP-A-2-160588 JP-A-6-40171 JP 7-47774 A

  However, in the method proposed in Patent Document 1, although heat conduction can be made uniform by ultrafine particles, the dispersion of particles in the dye layer tends to be insufficient by adding two types of particles having different particle sizes. When the dye is transferred to the receiving layer during thermal transfer, local unevenness occurs, and the transferred image becomes rough and the color reproducibility and resolution deteriorate. Further, in the method proposed in Patent Document 2, depending on the hardness and melting point of the particles, the transferred image may become rough, and the color reproducibility and resolution may decrease, and is about 0.5 μm used in the examples. With these particles, the problem of blocking between the surface of the thermal transfer sheet of the thermal transfer sheet and the surface of the thermal transfer sheet not provided with the thermal transfer layer cannot be solved. Further, in the method proposed in Patent Document 3, since the melting point is high, the releasability at the time of transfer becomes a problem. In addition, the method proposed in Patent Document 4 improves the slipperiness, releasability and thermal transfer sheet storage with respect to the image receiving sheet, but the dye transfer at the time of transfer is hindered by polyethylene wax, and sufficient sensitivity is obtained. I can't. Further, in the method proposed in Patent Document 5, the dispersion of the particles in the dye layer tends to be insufficient by adding two kinds of particles having different particle diameters, and the dye is transferred to the receiving layer during thermal transfer. May cause local unevenness and affect the formed image.

  In view of the above problems, even if the thermal transfer recording medium is held in a roll wound around a winding shaft for a long time, the dye or additive contained in the thermal transfer layer of the thermal transfer recording medium is provided with the thermal transfer layer of the thermal transfer recording medium. The surface of the thermal transfer layer and the surface of the thermal transfer recording medium not provided with the thermal transfer layer are prevented from blocking, and further, due to heat generated when the thermal transfer layer surface faces the surface of the thermal transfer body during printing. It is an object to provide a thermal transfer recording medium capable of performing high-sensitivity and non-uniform transfer while preventing fusion to the surface of a thermal transfer body.

  The inventors of the present invention can achieve the above-mentioned problem by forming a part or all of the surface of the thermal transfer layer into an uneven shape by pushing up a part of the surface of the thermal transfer layer with particles contained in the thermal transfer layer. The headline and the present invention were completed.

  That is, the invention described in claim 1 is a thermal transfer recording medium in which at least a color material layer is provided on a support, the color material layer contains at least a binder and particles, and the entire surface of the particles is coated with the binder. In addition, the thermal transfer recording medium is characterized in that a part or all of the surface of the color material layer has an uneven shape.

  The invention according to claim 2 is characterized in that the value of r / h satisfies the following equation, where r is the average particle diameter of the particles and h is the film thickness of the color material layer. This is a thermal transfer recording medium.

0.5 ≦ r / h ≦ 1.0
The invention according to claim 3 is the thermal transfer recording medium according to claim 1 or 2, characterized in that the color material layer contains a release agent.

The invention according to claim 4 is characterized in that an easy adhesion layer is provided between the support and the color material layer.
The thermal transfer recording medium according to any one of claims 1 to 3.

  The invention according to claim 5 is the thermal transfer recording medium according to any one of claims 1 to 4, wherein the thermal transfer layer is a layer containing a dye.

  By using the method of the present invention, even if the thermal transfer recording medium is held in the form of a roll wound around a winding shaft for a long time, the dyes and additives contained in the thermal transfer layer of the thermal transfer recording medium are used in the thermal transfer layer of the thermal transfer recording medium. Prevents blocking of the surface of the thermal transfer layer and the surface of the thermal transfer recording medium where the thermal transfer layer is not provided, and prevents the surface of the thermal transfer layer from facing the surface of the thermal transfer body during printing. The effect of performing high-sensitivity and non-uniform transfer while preventing unnecessary fusion to the surface of the thermal transfer body due to heat is exhibited.

  Hereinafter, the present invention will be described in more detail. FIG. 1 is a cross-sectional view of the thermal transfer recording medium 1. The thermal transfer recording medium 1 includes a support 2 and a thermal transfer layer 3. The support 2 can be the same as that conventionally used as a base material for thermal transfer recording media, and preferably has mechanical strength, flexibility, heat resistance and the like. Specific examples include polyethylene terephthalate, polyethylene naphthalate, polypropylene, cellophane, polycarbonate, polyvinyl chloride, polystyrene, polyimide, nylon, polyvinylidene chloride and other plastic films, condenser paper, paraffin paper and the like. However, polyethylene terephthalate is particularly preferable. The thickness of the support 2 is 2 to 25 μm, more preferably 2 to 12 μm.

  Further, in order to prevent thermal contraction of the support 2 due to the heat of the thermal head and breakage of the support 2 due to friction with the thermal head, a heat resistant slipping layer is provided on the surface of the support 2 opposite to the thermal transfer layer 3. It may be provided. Examples of materials used for the heat resistant slipping layer include cellulose resins, polyester resins, acrylic resins, vinyl resins, and polyurethane resins. For the purpose of improving the heat resistance, a crosslinking agent may be used in combination. Further, for the purpose of improving lubricity, a lubricant such as silicone oil may be used in combination, or the above-mentioned resin modified with silicone may be used.

  Moreover, in order to improve the adhesiveness between the support body 2 and a heat resistant slipping layer, you may provide an easily bonding layer on the support body 2, and you may provide a heat resistant slipping layer on it. On the contrary, when the heat resistant slipping layer is not provided, the heat resistance and the slipperiness may be improved by adjusting the surface roughness of the surface of the support 2 in contact with the thermal head by various methods.

  In the thermal transfer layer 3, the components contained in the thermal transfer layer 3 or the thermal transfer layer 3 itself is transferred onto the thermal transfer body from the surface opposite to the thermal transfer layer 3 of the thermal transfer recording medium 1 by heating with a thermal head. A layer containing a color material for forming characters and images. For example, when the thermal transfer layer 3 contains a sublimable dye, the dye is sublimated by heating with a thermal head and transferred onto the thermal transfer medium. Further, when the thermal transfer layer 3 is a melt transfer layer having heat melting properties, the thermal transfer layer 3 itself is transferred onto the thermal transfer body, and characters and images are formed on the thermal transfer body.

  The thermal transfer layer 3 contains a color material and a binder. For example, a conventionally known sublimable dye can be used as the color material. Specifically, examples of yellow include Kayaset Yellow AG, Kayaset Yellow TDN, PYT52, Plast Yellow 8040, Holon Brilliant Yellow S6GLPI, and the like. Examples of magenta include Kaya Set Red B, Kaya Set Red 130, Ceres Red 7B, Macrolex Red Violet R, and the like. Examples of cyan include Kayaset Blue 714, Ceres Blue GN, MS Blue 50, and the like.

  As a binder used for the thermal transfer layer 3 in combination with a sublimation dye, conventionally known binders can be used, such as polyvinyl acetal resin, polyvinyl butyral resin, polyester resin, phenoxy resin, styrene-acrylonitrile copolymer resin, ethyl cellulose, hydroxyethyl cellulose. Resins excellent in heat resistance, dye transferability, etc., such as polycarbonate, can be used.

  The glass transition temperature of the binder resin used for the thermal transfer layer 3 in combination with the sublimation dye is desirably 50 ° C. or higher. When the glass transition temperature is 50 ° C. or lower, the thermal transfer layer 3 is fused to the thermal transfer body during thermal transfer. This is not preferable because it tends to be easy to perform and a problem occurs in the storage stability of the thermal transfer recording medium. Furthermore, the ratio of the sublimable dye and the binder in the thermal transfer layer 3 is preferably 100: 50 to 100: 300.

  The heat transfer layer 3 of the heat melting transfer type contains a color material, a binder, and a wax. As the coloring material, a known pigment can be used. For example, carbon black is preferable for black monochromatic printing, and for multicolor printing, pigments for forming yellow, magenta, and cyan, and four-color pigments obtained by adding black to these three-color pigments are used. These pigments can be used alone or in combination of two or more.

  Examples of organic pigments used in the thermal transfer transfer type thermal transfer layer 3 include azo pigments such as phthalimide yellow, benzimidazolone orange, sulfoamide yellow, and benzimidazolone yellow, phthalocyanine pigments, diketopyrrolopyrrole, Examples include quinophthalone, isoindolinone, and diaminodianthraquinone.

  Examples of the binder used for the heat-melt transfer type thermal transfer layer 3 include an ethylene-vinyl acetate copolymer, a polyamide resin, a rosin derivative, an acrylic resin, and an epoxy resin. As the wax, paraffin wax, microcrystalline wax, carnauba wax, montan wax, polyethylene wax, ester wax, oxidized wax, or the like is used.

  Examples of the binder of the thermal transfer layer 3 used as the protective layer include polyester resin, vinyl resin, acrylic resin, epoxy resin, vinyl chloride / vinyl acetate copolymer, and the like. These resins may be used alone or in combination of two or more. In this case, a release layer may be provided in order to improve the release property between the support 2 and the protective layer during thermal transfer, and nitrocellulose is particularly preferable as the binder. Further, an adhesive layer may be provided on the surface of the protective layer in order to improve the adhesion between the receiving layer and the protective layer after transfer. Examples of the composition of the adhesive layer include an acrylic resin, a cellulose derivative, a styrene resin, a vinyl resin, a polyester resin, a polyamide resin, a polyurethane resin, and the like, and one kind or a mixture of two or more kinds may be used.

In the present invention, in particular, when the thermal transfer layer 3 is a dye layer, it is possible to prevent dye back-off and blocking and to improve releasability from the receiving layer.
The thermal transfer layer 3 of the present invention contains at least particles 4. A cross-sectional view of the thermal transfer layer 3 containing particles is shown in FIG. As a feature of the present invention, it is preferable that a part of the surface of the thermal transfer layer is pushed up by the particles so that the particles have an uneven shape without being exposed. That is, it is preferable that the surface of the thermal transfer layer 3 is raised due to the presence of particles in the thermal transfer layer 3. Conversely, the shape in which the particles themselves are exposed from the surface of the thermal transfer layer as shown in FIG. 3 is not preferable because local unevenness occurs during thermal transfer.
The particles shown in FIGS. 2 and 3 are spherical, but this is only an example, and it may be spherical or non-spherical. It is only necessary that the surface of the thermal transfer layer is pushed up by the particles so that the particles have an uneven shape without being exposed.
Further, the average particle diameter is not limited as long as the particles themselves are not exposed from the surface of the thermal transfer layer as shown in FIG. 3, but the content of the particles contained in the thermal transfer layer ink forming the thermal transfer layer and the coating amount thereof. The presence or absence of exposure differs depending on. Therefore, when the average particle diameter of the particles is r and the film thickness of the thermal transfer layer is h, it is preferable that the value of r / h satisfies 0.5 ≦ r / h ≦ 1.0. When the value of r / h is smaller than 0.5, the bulge on the surface of the thermal transfer layer is reduced, resulting in a decrease in releasability and blocking on the surface of the thermal transfer member. The maximum value of r / h is 1.0, and h ′ shown in FIG. 3 is the film thickness of the portion where no particles exist in the thermal transfer layer.

  The film thickness of the thermal transfer layer is 0.2 to 5.0 μm, preferably about 0.4 to 3.0 μm. If the thickness is less than 0.2 μm, sufficient color development sensitivity cannot be obtained, and if it exceeds 5.0 μm, the color development sensitivity is deteriorated.

  The particles may be either organic particles or inorganic particles, and it is sufficient that the particles have an uneven shape without being exposed when the surface of the thermal transfer layer is partially pushed up by the particles. The particles may be used alone or in combination of two or more.

  A release agent may be contained in the thermal transfer layer. When a release agent is contained, the release effect due to the shape of the surface of the thermal transfer layer is further improved. For example, various oils such as silicone-based, fluorine-based, and phosphate ester-based materials, surfactants, various fillers such as metal oxides, silica, and the like can be used. Among these, it is preferable to use silicone oil.

  In order to improve the adhesion between the support 2 and the thermal transfer layer 3, an easy adhesion layer may be provided as an intermediate layer. In addition, a surfactant, an antiblocking agent, an antioxidant, an ultraviolet absorber, an antistatic agent, etc. may be added to the thermal transfer layer 3 as necessary, and a layer having these functions is laminated. May be.

  The thermal transfer layer 3 is formed by applying a coating solution for forming the thermal transfer layer onto the support 2 by a wet coating method such as bar coating, blade coating, air knife coating, gravure coating, roll coating, and the like, and then drying.

  The thermal transfer member is composed of a support and a receiving layer. The support can be the same as that used as the base material of the thermal transfer recording medium, and preferably has mechanical strength, flexibility, heat resistance and the like. Specifically, polyesters such as polyethylene terephthalate and polyethylene naphthalate, plastic films such as polyethylene, polyvinyl chloride, polycarbonate, polyester, polysulfane, polyimide, polyvinyl alcohol, aromatic polyamide, and aramid film, fine paper, Examples thereof include paper base materials such as coated paper and synthetic paper. Although there is no limitation in particular in the thickness of this support body, Generally 25-250 micrometers, Furthermore, 75-200 micrometers is preferable.

  As the receiving layer, when a sublimation dye is used for the thermal transfer layer, for example, butyral resin, polyethylene, polyurethane, polypropylene, polyvinyl chloride, polybutadiene, polyvinyl acetate, vinyl chloride-acetic acid having dyeing properties. Thermoplastic resins such as vinyl copolymers, ethylene-vinyl acetate copolymers, polyamides, polyesters, polycaprolactones, polyvinyl acetals, epoxies, ketones, modified resins and blended products thereof, cross-linked products of these, etc. Can be used. These may be used alone or in combination of two or more. When the film thickness of the receiving layer is too thin, the reflection density of the image decreases, and it becomes difficult to form a sufficient image. On the other hand, if the thickness is too large, image quality such as color bleeding is deteriorated. Therefore, it is generally 1 to 30 μm, preferably 3 to 10 μm. In this case, the receiving layer preferably contains various release agents for the purpose of preventing thermal fusion to the thermal transfer recording body during image formation. As such a release agent, a known release agent can be appropriately selected and used. For example, various oils such as silicone-based, fluorine-based, and phosphate-based oils, various fillers such as surfactants, metal oxides, and silica can be used, and among these, silicone oil is preferably used. Moreover, although the addition amount changes with structural conditions of a receiving layer, generally it is preferable to mix | blend by 1 to 30 weight%.

  Hereinafter, specific examples of one embodiment of the present invention will be described.

<Example 1>
An ink composition for the thermal transfer layer having the following composition was prepared and applied to a polyethylene terephthalate film having a thickness of 4.5 μm with a heat-resistant slip treatment on the back so that the thickness of the thermal transfer layer after drying was 3.0 μm. It was dried to obtain the thermal transfer recording medium of the present invention.
[Ink for thermal transfer layer]
・ Cyan dye (Nippon Kayaku Co., Ltd., Kayaset Blue 714) 5.0 parts ・ Silicone fine particles (Momentive Performance Materials Tospearl 120, average particle size: 2.0 μm) 0.3 parts ・ Butyral resin ( Sekisui Chemical Co., Ltd., ESREC BX-1) 5.0 parts, methyl ethyl ketone 45.0 parts, toluene 45.0 parts

Next, a foamed polypropylene film (thickness: 50 μm) / adhesive resin layer / coated paper (basis weight: 108 g / m ² ) / adhesive resin layer / foamed polypropylene film (thickness: 50 μm) was used as the base sheet. On the surface, the following receiving layer ink was applied and dried so that the film thickness after drying was 4 μm, and then subjected to aging at 45 ° C. for 1 week to obtain a transferred body with a receiving layer.
(Receptive layer ink)
・ Vinyl chloride-vinyl acetate copolymer (manufactured by Nissin Chemical Industry Co., Ltd., Solvein A) 50.0 parts ・ Silicone oil (manufactured by Shin-Etsu Chemical Co., Ltd., KF393) 2.0 parts ・ Methyl ethyl ketone 25.0 parts ・ Toluene 25 .0 part

<Example 2>
A thermal transfer recording medium of the present invention was obtained in the same manner as in Example 1 except that the coating amount was adjusted so that the film thickness of the thermal transfer layer in Example 1 was 3.5 μm.

<Example 3>
A thermal transfer recording medium of the present invention was obtained in the same manner as in Example 1 except that the coating amount was adjusted so that the film thickness of the thermal transfer layer in Example 1 was 4.0 μm.

<Example 4>
A thermal transfer recording medium of the present invention was obtained in the same manner as in Example 1 except that the average particle size of the silicone fine particles of Example 1 was changed to 3.0 μm (Tospearl 130 manufactured by Momentive Performance Materials).

<Comparative Example 1>
A thermal transfer recording medium of the present invention was obtained in the same manner as in Example 1 except that the content of the silicone fine particles contained in the thermal transfer layer ink of Example 1 was changed from 0.3 part to 0.5 part.

<Comparative Example 2>
A thermal transfer recording medium of the present invention was obtained in the same manner as in Example 1 except that the coating amount was adjusted so that the film thickness of the thermal transfer layer in Example 1 was 5.0 μm.

<Comparative Example 3>
The average particle diameter of the silicone fine particles of Example 1 was changed to 4.5 μm (Tospearl 145 manufactured by Momentive Performance Materials), and the film thickness (h ′) of the portion where no particles exist in the thermal transfer layer was changed to 3.0 μm. The thermal transfer recording medium of the present invention was obtained in the same manner as in Example 1 except that the coating amount was adjusted so as to be.
Regarding the shape of the thermal transfer layer surface of the obtained thermal transfer recording medium, the thermal transfer recording medium was cut with a microtome, and the vicinity of the obtained thermal transfer layer surface was observed using a scanning electron microscope (SEM). Thereby, the presence or absence of the protrusion of the thermal transfer layer by particles was confirmed, and the film thickness h of the thermal transfer layer was measured.

Next, the thermal transfer layer surface of the obtained thermal transfer recording medium and the receiving layer surface of the transfer target were overlapped, and the dye was transferred using a thermal head to form an image.
The following evaluation was performed on the obtained image. The results are shown in Table 1.
〔Evaluation item〕
・ Releasability during transfer: It was confirmed whether or not the dye layer of the thermal transfer recording medium sticks to the receiving surface of the transfer medium during transfer. When sticking did not occur, it was evaluated as “Good”, when it was generated, “X”, and when slightly adhered, it was evaluated as “△”.
-Dye set-off: The heat transfer recording medium cut out to 100 mm x 100 mm is faced with the heat-resistant slipping layer on the back side, and left at room temperature for 200 hours while applying a 1 kg load. The presence or absence of setback to the sex layer was confirmed. When there was no set-off, it was evaluated as “Good”, when there was “No”, and when there was a little, “Good”.
-Blocking: Check the peeling sound generated when unwinding the thermal transfer recording medium stored in a roll for a long time. If there is no peeling sound, it is evaluated as ◯. If there is peeling sound, it is evaluated as △. did.
Roughness of the image: The image after printing was visually confirmed. The evaluation was evaluated as “◯” when the image was not rough, “X” when the image was rough, and “△” when the image was slightly rough.

As described above, according to the present invention, even when the thermal transfer recording medium is held in a roll wound around a winding shaft for a long period of time, the dye or additive contained in the thermal transfer layer of the thermal transfer recording medium does not cause the thermal transfer of the thermal transfer recording medium. Prevents blocking of the surface of the thermal transfer layer and the surface of the thermal transfer recording medium not provided with the thermal transfer layer, and prevents the thermal transfer layer surface from facing the surface of the thermal transfer body during printing. It was possible to perform high-sensitivity and non-uniform transfer while preventing fusion to the surface of the heat-transferred transfer member due to heat. From Comparative Example 1 and Comparative Example 3, when the amount of added particles is large and when the particle size is large, the particles are exposed and a sufficient effect cannot be exhibited. It was confirmed that the effect was small even when the film thickness after drying of the thermal transfer layer was smaller than a certain level.

It is a cross-sectional schematic diagram of one embodiment of the thermal transfer recording medium of the present invention. It is sectional drawing of the thermal transfer layer 3 containing the particle | grains of one Embodiment of the thermal transfer recording medium of this invention. It is sectional drawing of the thermal transfer layer 3 (comparative example) containing particle | grains.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Thermal transfer recording medium 2 ... Support body 3 ... Thermal transfer layer 4a-4f, 4a'-4f '... Particle | grain h ... Film thickness h' of a color material layer ... Film thickness of the part in which the particle | grain does not exist in a thermal transfer layer

Claims (5)

  In a thermal transfer recording medium in which at least a color material layer is provided on a support, the color material layer contains at least a binder and particles, and the entire surface of the particles is covered with the binder, and one surface of the color material layer is formed. A thermal transfer recording medium, characterized in that all or all of the portions have an uneven shape. 2. The thermal transfer recording medium according to claim 1, wherein the value of r / h satisfies the following formula, where r is an average particle diameter of the particles and h is a film thickness of the color material layer.
0.5 ≦ r / h ≦ 1.0   The thermal transfer recording medium according to claim 1, wherein the color material layer contains a release agent.   The thermal transfer recording medium according to any one of claims 1 to 3, wherein an easy adhesion layer is provided between the support and the color material layer.   The thermal transfer recording medium according to any one of claims 1 to 4, wherein the thermal transfer layer is a layer containing a dye.