JP2000052668A - Method for thermal transfer recording and image receiving sheet used therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for thermal transfer recording with excellent sensitivity and image preservability without image fault by enhancing adhesive properties with a thermal head or the like and an image receiving sheet used therefor. SOLUTION: In the method for thermal transfer recording comprising the steps of superposing an ink layer surface of an ink sheet having at least one ink layer containing a thermal diffusible dye precursor on a support to be opposed with an image receiving layer surface of an image receiving sheet having least one image receiving layer containing dye fixing material for forming a dye in reaction with the precursor on the support, heating it in an image-like state and transferring the precursor to the image receiving layer; the support of the sheet is formed of a composite film of at least two or more layers of a first layer made of a composition containing a polyester resin as a main component and a layer having a higher apparent specific gravity than that of the first layer, and the apparent specific gravity of the composite film is 0.6 to 1.1.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermal transfer recording method for recording an image by thermal transfer and an image receiving sheet used for the method. The present invention relates to a thermal transfer recording method excellent in storability and an image receiving sheet used for the method.

[0002]

2. Description of the Related Art As a technique for forming a color or monochrome image, an ink sheet containing a sublimable dye having a property of diffusing and transferring upon heating is opposed to an image receiving layer of an image receiving sheet, and heated by a thermal head or a laser. A technique is known in which an image is formed by transferring the sublimable dye imagewise to the image receiving layer using a printing unit.

Conventionally, as an image receiving sheet used for such thermal transfer recording, a sheet having a support as a paper and an image receiving layer formed on the surface thereof has been used. However, this method has insufficient surface smoothness. Therefore, in recent years, as a support, a synthetic paper made of a thermoplastic resin film, or the thermoplastic resin film, a bonding, laminating, etc. on a core material such as paper or the synthetic paper or the like by means such as lamination. The mainstream is a laminated product or the like, which is provided with an image receiving layer on its surface.

[0004] As a thermoplastic resin film used in such a configuration, generally, a film containing voids is often used. As means for containing cavities, for example, a method of blending a thermoplastic resin with an inorganic particle such as titanium dioxide or calcium carbonate, a crystalline resin incompatible with the thermoplastic resin, and stretching is known. ing. The reason for containing the cavities is to make the thermoplastic resin opaque by light scattering by the cavities and increase the whiteness, as well as to lower the specific gravity and give it cushioning properties, to increase the adhesion with the thermal head, improve image quality, The purpose is to improve sensitivity.

[0005] When the void-containing film is used as a support for a thermal transfer recording material, if the cushioning property is insufficient, if foreign matter or the like is present on the image receiving sheet or in the image receiving layer, the shape of the foreign matter depends on the shape of the foreign matter. When the thermal head follows the image, the image is not transferred only to that area, resulting in a foreign image defect or when the film is laminated on the core material, the thermal head follows the irregularities on the core material surface This may cause an image defect (hereinafter, also referred to as formation unevenness) corresponding to the uneven shape of the image.

However, if the content of cavities is simply increased to lower the specific gravity of the film in order to satisfy the cushioning property, the size of the cavities becomes extremely large, and the smoothness of the film surface is lost. There are problems such as easy formation of wrinkles, remarkable reduction in image quality, and reduction in production stability and inability to carry out stable production.

[0007] In particular, when it is desired to use a polyester-based void-containing film, the void content must be further increased because of the relatively high rigidity and low cushioning properties of other thermoplastic resins. It is difficult to reduce the specific gravity even if whiteness is obtained, and when a polyolefin resin or the like is added as an incompatible resin, the cushioning property is increased as compared with the addition of inorganic particles, but the surface free energy is reduced. Therefore, the adhesiveness and printability tend to be inferior, and it has been extremely difficult to improve the above-mentioned defect while satisfying the cushioning property with the current polyester film.

On the other hand, with respect to the storability of an image obtained by the thermal transfer recording method, the dye used for the ink sheet plays an important role, but the conventional dye always has sufficient storability to withstand use. It is not currently done. Therefore, in order to improve this point, an image forming method using a so-called reactive dye has been proposed in which an image is formed by reacting a dye precursor and a dye fixing body. For example, JP-A-9-327976, U.S. Pat.
0,769, US Patent No. 5,534,479, etc.
A method for forming an image by reprotonating the cationic dye by thermal transfer using a deprotonated cationic dye as a dye precursor, an organic polymer acid or oligomeric acid capable of protonating the cationic dye as a dye fixing body, and the like. Proposed. Also, JP-A-5-22115
No. 1 and the like propose a method of forming an image by using a dye having a specific structure having a reactive group as a dye precursor and an active hydrogen compound as a dye fixing body and reacting them by thermal transfer. Further, Japanese Unexamined Patent Publication No. Sho 59-78893
JP-A-59-109394, JP-A-60-239
No. 8 and the like, a chelateable heat-diffusible compound (hereinafter, also referred to as a post-chelating dye) is used as a dye precursor, and a metal ion-containing compound (hereinafter, a metal source) is used as a dye fixing body by thermal transfer. ) To form an image.

When an image is formed using such a reactive dye, the higher the reaction rate is, the better the fixing property is, and the better the storability is. That is, the higher the heat insulating property of the image receiving sheet, the higher the reaction rate because the heat is not diffused. Therefore, it is important to increase the thermal efficiency not only from the image receiving sheet, especially from the image receiving layer, but also from the support.

[0010]

SUMMARY OF THE INVENTION Accordingly, the present invention provides a thermal transfer recording method which enhances adhesion to a thermal head and the like, has no image defects, is excellent in sensitivity and image storability, and an image receiving sheet used therefor. That is the task.

[0011]

A thermal transfer recording method according to the present invention for solving the above-mentioned problems is the invention according to claim 1, which comprises a substrate containing a heat-diffusible dye precursor. The ink layer surface of the ink sheet having at least one ink layer is opposed to the image receiving layer surface of the image receiving sheet having at least one image receiving layer containing a dye fixing body capable of forming a dye by reacting with the dye precursor on a support. In the thermal transfer recording method of forming an image by transferring the dye precursor to the image receiving layer by heating the image receiving layer, the support of the image receiving sheet contains a polyester resin as a main component. And a composite film having at least two layers including a first layer made of a composition and a layer having an apparent specific gravity higher than that of the first layer.
6 to 1.1, a thermal transfer recording method.

An image receiving sheet according to the present invention for solving the above-mentioned problems is the invention according to claim 12, wherein the support comprises at least one ink layer containing a heat-diffusible dye precursor on a support. The ink layer surface of the ink sheet having a layer and the image receiving layer surface of the image receiving sheet having at least one image receiving layer containing a dye fixing body capable of forming a dye by reacting with the dye precursor on a support are superposed on each other so as to face each other. In an image-receiving sheet used in a thermal transfer recording method for forming an image by heating the image and transferring the dye precursor to the image-receiving layer, the support of the image-receiving sheet contains a polyester resin as a main component. The composite film comprises at least two or more composite films including a first layer composed of a composition and a layer having a higher apparent specific gravity than the first layer, and the apparent specific gravity of the composite film is 0.6 to 1.1. It is an image-receiving sheet and said Rukoto.

In a preferred embodiment of the thermal transfer recording method according to the first aspect, the present invention is applied to the second to eleventh aspects.
Preferred embodiments of the image receiving sheet according to claim 2 are claims 13 to 2.
This is the invention described in Item 1.

The invention according to claim 11 is characterized in that the dye precursor is a chelatable compound and the dye fixing body is a metal ion-containing compound. The thermal transfer recording method according to any one of the above.

The invention according to claims 2 and 13 is characterized in that the first layer of the composite film comprises a polyester resin and a composition of a styrene polymer having a syndiotactic structure.

According to a third aspect of the present invention, the first layer of the composite film comprises a composition of a polyester resin, a styrene polymer having a syndiotactic structure, and a polyester polyether copolymer. It is characterized by the following.

The invention according to claims 4 and 15 is characterized in that the first layer of the composite film has an apparent specific gravity of 0.3 to 1.0.

[0018] The invention described in claims 5 and 16 is characterized in that the layers other than the first layer of the composite film are layers composed of a composition containing a polyester resin as a main component.

The invention according to claims 6 and 17 is characterized in that the composite film is provided with a first layer and a layer composed of a polyester resin as a main component on at least one surface of the first layer. It is characterized by being.

The invention described in claims 7 and 18 is characterized in that the layer provided on at least one side of the first layer of the composite film is a layer substantially free of voids.

The invention according to claims 8 and 19 is characterized in that the composite film is produced by simultaneous extrusion and subsequent biaxial stretching.

According to a ninth and twentieth aspect of the present invention, the support of the image receiving sheet is formed by laminating the composite film according to any one of the first to eighth aspects on at least one surface of a core material. It is characterized by.

The invention according to claims 10 and 20 is characterized in that the core material is made of synthetic paper containing fiber paper or plastic film.

[0024]

Embodiments of the present invention will be described below.

In the image receiving sheet used in the thermal transfer recording method of the present invention, as a support, a layer composed of a composition containing a polyester resin as a main component (hereinafter, referred to as an A layer) and a layer having an apparent specific gravity higher than the A layer ( A composite film having an apparent specific gravity of 0.6 to 1.1 or more, including at least two layers including a layer B), or a laminate of the composite film and a core material is used.

Although those having an apparent specific gravity of less than 0.6 are possible in production, they are not preferable because of problems such as deterioration of film surface smoothness, breakage wrinkle resistance and production stability. On the other hand, when the ratio is larger than 1.1, the cushioning properties are insufficient, and the effects of the present invention cannot be obtained.

In the present invention, the layer A may be present at any position in a plurality of layers constituting the composite film.
In order to prevent the lowering of the smoothness and the wrinkle resistance due to the reduction in specific gravity described above, a layer (B layer) having an apparent specific gravity higher than that of the A layer is provided on at least the surface of the A layer having the image receiving layer. Is preferred. Preferably, a layer having an apparent specific gravity higher than that of the layer A (hereinafter, referred to as a layer C) is similarly provided on the surface opposite to the layer B in order to have the above-mentioned mechanical strength required for the image receiving sheet. In addition, in the case of laminating on the core material, it is preferable to increase the adhesiveness with the core material.

The thickness and composition of the layer B and the layer C may be the same or different. For example, in the case of using the film of the present invention alone as a support, it is preferable to change the thickness of the front and back layers in order to reduce curl due to thermal shrinkage during printing.

The layer B and / or the layer C is not particularly limited as long as it satisfies the condition of apparent specific gravity in the form of a film such as paper, nonwoven fabric, metal foil, resin, etc. The layer is preferably a layer composed of a composition containing polyester as a main component.

In order to improve the winding property of the film, inorganic or organic particles may be added to the layer B and / or the layer C. As the inorganic particles, those usually added to polyester can be used, and examples thereof include calcium carbonate, titanium dioxide, barium sulfate, alumina, and silica. Further, as the organic particles, silicon resin particles, crosslinked acrylic particles, crosslinked polystyrene particles, and the like can be used.

The preferred average particle size of the inorganic particles is 0.1 to 1
0 μm, more preferably 0.5 to 5 μm.

When the inorganic particles are added, the amount of the inorganic particles is 0.1.
The content is preferably from 0.01 to 30% by weight, more preferably from 0.01 to 30% by weight.
-20% by weight. If the addition amount is less than 0.01% by weight, the slipperiness of the film may be reduced and handling may be deteriorated. Conversely, if the content exceeds 30% by weight, the inorganic particles may be scraped off during stretching, and the roll may be soiled. However, the addition of the inorganic particles to the layer B has the above-described effects, but the surface smoothness and gloss are reduced due to the formation of voids (voids). Is preferably minimized or not added.

The lamination ratio is preferably such that the thickness of the layer A is 80% or more, more preferably 90% or more. If the thickness constituting ratio is less than 80%, sufficient cushioning properties cannot be obtained. On the other hand, if it is close to 100%, the effect of the layer provided thereon cannot be obtained, so the upper limit is preferably about 95%. By adopting such a configuration, it is possible to improve printability such as adhesiveness and image quality by using another layer while obtaining a target cushioning property by the A layer.

The polyester resin used as a main component in the layer A includes terephthalic acid, isophthalic acid, naphthalenedicarboxylic acid phthalate, adipic acid, sebacic acid, and dicarboxylic acids such as dimethyl ester thereof, and ethylene esters thereof. It is a polymer obtained by polycondensing diols such as glycol, diethylene glycol, trimethylene glycol, tetramethylene glycol, cyclohexan dimethanol, 1,4-butanediol and neopentyl glycol. Specific examples of such polyester resins include polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polyethylene-p-oxybenzoate, poly-1,4-cyclohexylene dimethylene terephthalate, and polyethylene-2,6- Naphthalate (PEN) and the like.

In the case of the present invention, an antioxidant is contained in the polyester resin within a range not to impair the effects of the present invention.
Various additives such as an antistatic agent, organic fine particles, and inorganic fine particles may be added.

The apparent specific gravity of the layer A is preferably from 0.3 to 1.0. The resin used for the layer A is preferably a composition of a polyester and a styrene-based polymer having a syndiotactic structure in order to further enhance the effects of the present invention.

The styrenic polymer having a syndiotactic structure as referred to in the present invention means a phenyl group whose stereochemical structure is mainly a syndiotactic structure, that is, a phenyl group which is a side chain to a main chain formed from carbon-carbon bonds. Substituted phenyl groups have a steric structure alternately located in the opposite direction,
The tacticity is quantified by nuclear magnetic resonance ( ^13C -NMR) using isotope carbon. ¹³ C-NM
Tacticity measured by the R method can be represented by the ratio of the presence of a plurality of continuous structural units, for example, a dyad for two, a triad for three, and a pentad for five. The styrene-based polymer having a syndiotactic structure referred to in the invention means 75% or more, preferably 85% or more in a dyad, or 30% or more, preferably 50% in a pentad (racemic pentad).
It has the above syndiotacticity.

Examples of the styrenic polymer having a syndiotactic structure include polystyrene, poly (alkylstyrene), poly (halogenated styrene), poly (alkoxystyrene), poly (vinylbenzoic acid ester), and mixtures thereof. It refers to a copolymer containing these as main components. Here, the poly (alkylstyrene) includes poly (methylstyrene), poly (ethylstyrene), poly (isopropylstyrene), poly (t-butylstyrene), etc., and poly (halogenated styrene).
Examples thereof include poly (chlorostyrene), poly (bromostyrene), and poly (fluorostyrene). Also,
Examples of the poly (alkoxystyrene) include poly (methoxystyrene) and poly (ethoxystyrene). Of these, particularly preferred styrene polymers include polystyrene, poly (p-methylstyrene), and poly (m-styrene).
Methylstyrene), poly (pt-butylstyrene),
Examples thereof include poly (p-chlorostyrene), poly (m-chlorostyrene), poly (p-fluorostyrene), and a copolymer of styrene and p-methylstyrene.

The molecular weight of the styrene polymer having a syndiotactic structure used in the present invention is not limited, but the weight average molecular weight is preferably 10,000 or more, and most preferably 50,000 or more. Further, the molecular weight distribution is not limited in its width, and various types can be selected. Here, the weight average molecular weight is 100
If it is less than 00, the high-temperature compressibility of the obtained polyester film may be undesirably reduced.

It is preferable that such a styrene polymer having a predominantly syndiotactic structure be polymerized using a compound or complex containing titanium, zirconium, palladium or nickel metal as a catalyst. More preferably, they are polymerized with a Ziegler-type catalyst. In particular, metallocene catalysts, those polymerized using cyclopentadienyl-based or metallocene-based metal coordination catalysts collectively referred to as Kaminsky catalysts, or a combination of a titanium compound such as titanium halide or alkoxytitanium with alkylaluminosane Those polymerized using a catalyst (JP-A-62-230826) are most preferred.

For example, in an inert hydrocarbon solvent or in the absence of a solvent, a titanium compound and a condensation product of water and a trialkylaluminum are used as a catalyst to form a styrene monomer (a monomer corresponding to the styrene polymer). (Japanese Patent Application Laid-Open No. 62-187).
708). A specific example of the metallocene catalyst is disclosed in JP-A-62-257948.
Further, a styrene-based polymer having a higher syndiotactic structure is preferably used by a separation means using a solvent or the like, if necessary.

The styrenic polymer having a syndiotactic structure is dispersed in the polyester by melt extrusion molding, and has an effect of causing interfacial separation at the polymer dispersion interface in a subsequent stretching step to generate voids. In the case of the present invention, the polyester is a dispersion medium (matrix), and the styrene-based polymer having a syndiotactic structure is a dispersion.

The amount of the styrene polymer having a syndiotactic structure used in the layer A is preferably 2 to 25% by weight, more preferably 4 to 15% by weight. If the addition amount is less than 2% by weight, not only is it difficult to obtain a polyester film of the present invention having an apparent specific gravity of 1.0 or less, but also it may be difficult to obtain a polyester film having opacity. Conversely, if the amount of the styrene-based polymer exceeds 25% by weight, the mechanical properties of the polyester film of the present invention are reduced, the ejection stability during extrusion is poor, and the film is easily broken during stretching. Problems may occur.

In the present invention, an additive capable of finely dispersing a styrenic polymer having a syndiotactic structure dispersed in a polyester, that is, a so-called dispersant may be used. As the dispersant, either a low molecular type or a high molecular type can be used. As a specific example of the low molecular type, a surfactant used for an antistatic agent or the like is used. Among the low molecular types, nonionic surfactants are preferred. The polymer type is preferred because it does not easily bleed out to the surface and does not lower the adhesiveness, but is particularly preferably a polyester polyether copolymer.

Specifically, the polyester used as the polyester polyether copolymer includes polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polyethylene-p-oxybenzoate,
Poly-1,4-cyclohexylene dimethylene terephthalate (PCHDMT), polyethylene-2,6-naphthalate (PEN) and the like are used.

Examples of the polyether component to be copolymerized include polyethylene glycol (PEG) having a molecular weight of 300 to 20,000, methoxypolyethylene glycol, polytetramethylene glycol (PTMG), and polypropylene glycol (PPG).

Preferred polyester polyether copolymers include PET-PEG, PBT-PTMG, PC
There is HDMT-PPG. The copolymerization ratio of polyester to polyether is preferably from 1: 9 to 9: 1 by weight, more preferably from 4: 6 to 9: 1, and still more preferably from 4: 6 to 6: 4.

As a production method, a polyester polyether copolymer can be produced by adding a polyether at an optional stage in producing a polyester obtained by polycondensing an acid component and a glycol component.

The preferred range of the molecular weight of the polyether used is from 400 to 20,000, more preferably from 1,000 to 10,000.

The amount of the polyester polyether copolymer used in the layer A is preferably from 0.05 to 20% by weight, more preferably from 0.1 to 5% by weight. When the addition amount is less than 0.05% by weight, the syndiotactic polystyrene-based polymer is hardly finely dispersed, the generated voids are large, and the film is easily broken. Conversely, if the content exceeds 20% by weight, voids are less likely to be generated, and the specific gravity tends to increase.

The main component polyester in the layer A is 70%.
% By weight or more is good. If the content is less than 70% by weight, the mechanical strength and heat resistance, which are advantages of the polyester film, may not be exhibited.

The whiteness changes with the addition of the above-mentioned styrene-based polymer having a syndiotactic structure or a polyester polyether copolymer, but if necessary, a fluorescent whitening agent containing an inorganic fluorescent agent may be added. . As the fluorescent whitening agent, "UBITEC" OB, MD (manufactured by Ciba Geigy), "OB-1" (manufactured by Eastman) and the like are used.

Next, a preferred method for producing the composite film of the present invention will be described by taking polyester as an example, but the present invention is not limited to this.

A styrene polymer having a syndiotactic structure and a polybutylene terephthalate (PBT) -polytetramethylene glycol (PTMG) copolymer as a polyester polyether copolymer are mixed with polyethylene terephthalate. Dry thoroughly 2
Feed to extruder A heated to a temperature of 70-300 ° C. Also, polyethylene terephthalate and CaCO
Inorganic particles such as No. ₃ are supplied to the extruder B by a conventional method, and the polymer of the extruder B layer comes to one side or both surfaces of the A layer in a two-layer or three-layer die with A / B. Or B /
It may be laminated in two or three layers having a configuration of A / B. Here, the polymer mixture can be extruded by removing water during extrusion with a twin-screw extruder equipped with a vent.

The melted sheet was heated at a drum surface temperature of 1
While applying static electricity on the drum cooled to 0 to 60 ° C., the film is cooled and solidified by close contact, and the unstretched film is cooled to 75 to
Guided to a group of rolls heated to 120 ° C,
The film is stretched 5 times longitudinally and cooled with a group of rolls at 20 to 50 ° C. In order to obtain a white polyester film having a desired cushion rate, it is preferable to generate voids in this step. The obtained uniaxially stretched film can be subjected to corona discharge treatment and coated. Next, the uniaxially stretched film is guided to a tenter while holding both ends of the film with clips, and is horizontally stretched in a direction perpendicular to the machine direction in an atmosphere heated to 90 to 140 ° C. Stretch ratio is 2 for each of vertical and horizontal
The film is stretched up to 5 times, and the area magnification is desirably 6 to 20 times. If the area magnification is less than 6 times, the degree of whiteness is insufficient, and if it exceeds 20 times, the film tends to be broken at the time of stretching and the film-forming property tends to be poor.

In order to impart flatness and dimensional stability to the film thus biaxially stretched, 150-150.degree.
After heat setting at 230 ° C., the mixture is gradually cooled, cooled to room temperature, and wound. At the time of this heat fixing, it is possible to add a relaxation of 10% or less in order to reduce the heat shrinkage.
Thus, the polyester film of the present invention is obtained.

Further, as described above, a polyester film may be first produced under the above conditions, and a laminated layer may be laminated thereon by melt extrusion or coating. In the polyester film of the present invention, calcium carbonate,
Amorphous zeolite particles, anatase type titanium dioxide,
Fine particles such as calcium phosphate, silica, kaolin, talc and clay may be contained. In addition to the fine particles, fine particles precipitated by the reaction between the catalyst residue and the phosphorus compound in the polyester polycondensation reaction system can be used in combination. As the precipitated particles, for example, those composed of calcium, lithium and phosphorus compounds, or those composed of calcium, magnesium and phosphorus compounds are used, and the content of these particles in the polyester is based on 100 parts by weight of the polyester. It is preferably 0.05 to 1 part by weight.

In the present invention, the core material on which the composite film is laminated is a material to which heat is applied at the time of thermal transfer, so that it has mechanical strength, dimensional stability, heat shrinkage and the like that do not hinder handling even in a heated state. It is preferred to have. The material of such a core material is not particularly limited, but is preferably a fiber paper or a synthetic paper containing a plastic film.

Fiber paper is not limited to plain paper containing cellulose fiber as a main component, and especially when a composite film is bonded to only one side of the core material, the core material is made of glass to prevent curling of the core material due to a change in humidity. It is also preferable to use paper made by mixing fibers, plastic fibers such as polypropylene, polyethylene, etc., or inorganic fibers such as aluminum hydroxide with cellulose fibers. It is also preferable to provide a low layer.

As the synthetic paper, generally known synthetic paper can be used. Of course, the film of the present invention itself may be used.

Hereinafter, those usable as the core material in the present invention will be specifically described, but are not limited thereto.

Condenser paper, glassine paper, sulfuric acid paper, synthetic paper (polyolefin, polystyrene),
Fine paper, art paper, coated paper, cast coated paper, wallpaper, backing paper, synthetic resin or emulsion impregnated paper, synthetic rubber latex impregnated paper, synthetic resin internal paper, paperboard, etc., cellulose fiber paper, or polyester, polyacrylate, Polycarbonate, polyurethane, polyimide, polyetherimide, cellulose derivative, polyethylene,
Ethylene-vinyl acetate copolymer, polypropylene, polystyrene, acrylic, polyvinyl chloride, polyvinylidene chloride, polyvinyl alcohol, polyvinyl butyral,
Nylon, polyetheretherketone, polysulfone, polyethersulfone, tetrafluoroethylene / perfluoroalkylvinylether, polyvinylfluoride, tetrafluoroethylene / ethylene, tetrafluoroethylene / hexafluoropropylene, polychlorotrifluoroethylene, polyvinylidenefluor In order to enhance the clarity of the image formed in a later step, a white pigment or a filler (for example, titanium white, magnesium carbonate,
A white opaque film formed by adding zinc oxide, barium sulfate, silica, talc, clay, calcium carbonate, etc.) or a foamed sheet.

The composite film may be laminated on only one side of the core material or on both sides. When laminating on one side, it is laminated on the side on which the image receiving layer is provided. When laminating on both sides, the thickness of the composite film to be laminated may be changed on the front and back sides in consideration of curl balance and the like.

The method of laminating includes, for example, laminating with a conventionally known adhesive, extrusion laminating, laminating by heat bonding, etc., and is not particularly limited, and is appropriately determined according to the materials of the composite film and the core material. Selected. Specific examples of the adhesive include an ethylene-vinyl acetate copolymer, an emulsion adhesive such as polyvinyl acetate, a water-soluble adhesive such as polyester containing a carboxyl group, and the like.
As the adhesive for lamination, an adhesive of an organic solvent type such as a polyurethane-based or acrylic-based adhesive may be used.

The surface of the core material preferably has high smoothness, particularly on the side on which the image receiving layer is provided, from the viewpoint of reducing formation unevenness. The thickness of the core material is laminated on one side, laminated on both sides, or the thickness of the film to be laminated, the strength of the stiffness as a support, the transportability of the printer is not limited because various factors are involved, usually, The thickness may be determined so that the total thickness of the laminated films is about 10 to 500 μm. When the composite film is laminated on only one surface of the core material, a lubricating layer, an antistatic layer, a writing layer, and the like may be provided on the other surface as needed.

Next, the image receiving layer used in the present invention will be described.

The image receiving layer is formed from the ink layer of the ink sheet.
There is no particular limitation as long as it can receive the dye diffused by heating, and it is basically formed of a binder and various additives. As a method of forming an image receiving layer on the surface of a support, a coating solution for an image receiving layer is prepared by dispersing or dissolving a component for forming an image receiving layer in a solvent, and the coating solution for an image receiving layer is coated on the support. Or a coating method in which the mixture having the components for forming the image receiving layer is melt-extruded and then laminated on the surface of the support. The thickness of the image receiving layer formed on the surface of the support is generally 0.5 to 50 μm, preferably 1 to 50 μm.
It is about 20 μm.

As the binder for the image receiving layer, various binders such as a vinyl chloride resin, a polyester resin, a polycarbonate resin, an acrylic resin, a polyvinyl acetal resin and various heat resistant resins can be used. The type of the binder may be selected arbitrarily, but polyvinyl acetal-based resin or vinyl chloride-based resin is preferable in terms of image storability.

Examples of the polyvinyl acetal resin include a polyvinyl acetoacetal resin, a polyvinyl butyral resin, and a polyvinyl formal resin.

Examples of the vinyl chloride resin include a polyvinyl chloride resin and a vinyl chloride copolymer. Examples of the vinyl chloride copolymer include a copolymer of vinyl chloride and another comonomer containing vinyl chloride at a ratio of 50 mol% or more as a monomer unit.

In addition to the polyvinyl acetal resin and the vinyl chloride resin, a polyester resin can also be suitably used as the image receiving layer for thermal transfer. As the polyester resin, for example, polyethylene terephthalate,
Polybutylene terephthalate, JP-A-58-18869
No. 5, JP-A No. 62-244696.

Further, as the polycarbonate resin,
For example, various compounds described in JP-A-62-169694 can be used.

Examples of the acrylic resin include polyacrylester.

The heat-resistant resin is a known heat-resistant resin which is not a resin having an extremely low softening point or glass transition point (Tg), but is suitably compatible with the vinyl chloride resin and is substantially colorless. Various heat resistant resins can be used. The term “heat resistance” as used herein means that the resin itself does not undergo coloring such as yellowing when stored under heat, and the physical strength does not extremely deteriorate.

The heat-resistant resin has a softening point of 30 to 200.
C, especially preferably Tg of 50 to 150C. If the softening point is less than 30 ° C., the transfer of the heat transferable dye is not preferred because the ink sheet and the image receiving layer may be fused. If the softening point exceeds 200 ° C., the sensitivity of the image receiving layer is undesirably lowered.

Examples of the heat-resistant resin satisfying the above conditions include a phenol resin, a melamine resin, a urea resin, and a ketone resin. Among them, a urea aldehyde resin and a ketone resin are particularly preferable. Urea aldehyde resin is obtained by condensation of urea and aldehydes (mainly formaldehyde), and ketone resin is obtained by condensation reaction of ketone and formaldehyde.

The following resins can be further used as a binder for the image receiving layer.

Polyolefin resins such as polypropylene, other halogenated vinyl resins (eg, polyvinylidene chloride), other vinyl polymers (eg, polyvinyl acetate), polystyrene resins, polyamide resins, olefins such as ethylene and propylene And other vinyl monomers, ionomers, cellulose resins such as cellulose diacetate, polyurethane resins, polyimide resins, epoxy resins and the like.

Combination use of the polycarbonate resin described in JP-A-5-246152 and an aromatic polyester resin;

A polyvinyl acetal resin containing a carboxyl group described in JP-A-5-246151,
The above-mentioned polyvinyl acetal resin in which the component constituting the carboxyl group is a carboxyl group-containing addition-polymerizable monomer, a resin in which the monomer unit containing the carboxyl group is 0.5 to 20% by weight of the polyvinyl acetal resin;

An epoxy group-containing vinyl chloride copolymer resin described in JP-A-5-246150; a random-co-polycarbonate resin described in JP-A-5-131758; a JP-A-5-64978 A polyester resin wherein at least one of the diol component or the acid component described in 1) contains an alicyclic compound, wherein the alicyclic compound is tricyclodecanedimethanol, cyclohexanedicarboxylic acid, cyclohexanedimethanol or cyclohexanediol The resin improves the durability of the image, such as light resistance, fingerprint resistance, and plasticity);

A polyamide resin described in JP-A-4-299187 as an isophorozinamine component, a resin having a molecular weight of 5,000 to 20,000 and a softening point of 50 to 170 ° C .; Aqueous resin comprising a hydrophobic resin liquid described in JP-A-347690;
No.-299188, a polyamide resin having an amine value of 3 or less, a polyamide resin having a molecular weight in the range of 5,000 to 20,000 and a softening point of 50 to 170 ° C., and an acid component of dimer acid, propionic acid, and adipic acid Or the above polyamide resin selected from azelaic acid;

Polyurethane resin and polyester resin described in JP-A-4-299184;
No. 3194, a polymer substance having film-forming ability or film-forming ability, said polymer substance and B1 and / or B
Cured product of composition containing two components; JP-A-4-1312
No. 87; urethane-modified polyester resin described in JP-A-4-43082; JP-A-4-1
No. 35794, a vinyl chloride / vinyl acetate copolymer having an average degree of polymerization of 400 or less;

As described in JP-A-2-107485,
Acidic resins having an acid value of 2 or more, for example, the following acid-modified resins: (a) those having an ester bond, for example, polyester resin, polyacrylate resin, polycarbonate resin, polyvinyl acetate resin, styrene acrylate resin, vinyl Toluene acrylate resin, (b) those having a urethane bond, such as polyurethane resin,
(C) those having an amide bond, for example, polyamide resin (nylon); (d) those having a urea bond, for example, urea resin; (e) those having other highly polar bonds, for example, polycaprolactone resin, polystyrene Resins, polyacrylonitrile resins and the like (among these, particularly preferred are polyester resins);

The method described in JP-A-2-107485,
Reaction product of a thermoplastic resin and at least two or more compounds having a reactive functional group (an amino resin having a melamine skeleton, a urea skeleton, a benzoguanamine skeleton or a glycoluril skeleton, and an isocyanate compound);

A thermoplastic resin having a number-average molecular weight of 15,000 or less described in JP-A-7-40670 (excellent in quick-drying property during production, and excellent in releasability from a thermal transfer sheet during image formation, color density, and sharpness) Excellent) and 5-100% by weight of the binder of the image receiving layer as a thermoplastic resin (vinyl chloride-styrene copolymer, vinyl chloride-vinyl acetate-acrylic copolymer, vinyl chloride-acetic acid copolymer) Vinyl styrene copolymer, vinyl chloride butyl acryl styrene copolymer, vinyl chloride butyl acryl copolymer, vinyl chloride methacryl styrene copolymer, vinyl chloride vinyl methacrylate styrene copolymer, vinyl chloride butyl acryl methacryl styrene copolymer , Vinyl chloride vinyl acetate butyl acrylic methacryls Ren copolymer);

As described in JP-A-5-270151,
Aldehyde-modified vinyl alcohol resin and number average molecular weight 1
Polyester resin of 10,000 or less (effect: improvement in image density, light resistance, fingerprint resistance, durability such as thermoplasticity), aldehyde-modified vinyl alcohol resin having an aldehyde modification rate of 30
The average degree of polymerization of the above polyester resin and aldehyde-modified vinyl alcohol resin is from 200 to 3000%.
The polyester resin, wherein at least a part of the polyol component and / or the acid component of the polyester resin is an alicyclic compound, and the aldehyde modification is formalin, acetaldehyde or butyraldehyde (particularly preferably, acetaldehyde or butyraldehyde). The above polyester resin;

[0088] JP-A-6-115272 describes
Resin having a tensile strength of 200 kg / cm ² or more (effect: prevention of cracks in the image receiving layer, for example, polyester resin,
Polyurethane resin such as polyurethane resin, butyral resin, polypropylene etc., polyvinyl chloride, vinyl chloride / vinyl acetate copolymer resin, ionomer, cellulose resin such as cellulose diacetate, polycarbonate etc. (particularly preferably polyester resin And vinyl chloride / vinyl acetate copolymer resin);

A mixture of polyvinyl alcohol and an emulsion of a synthetic resin having a glass transition temperature of -100 to 20 ° C. and having a polar group described in JP-A-6-79974; A mixture of an aqueous dispersion of a polyester resin insoluble in a solvent and a sparingly soluble polyester resin and an aqueous dispersion of a thermoplastic resin other than the polyester resin described in JP-A-6-15966; Reaction products with isocyanates;

Reaction products of polyester resins and polyisocyanates described in JP-A-58-215398, JP-A-61-199997, JP-A-2-17889, and JP-A-2-86494. A reaction product of a vinyl chloride / vinyl acetate copolymer having active hydrogen and a polyisocyanate described in JP-A-1-160681, JP-A-1-123794, and JP-A-3-126587;

The hydroxyl group-containing thermoplastic resin described in JP-A-6-8646, for example, polyvinyl acetal resin, the polyvinyl acetal resin having a polyvinyl alcohol unit content of 5 to 50% by weight, vinyl chloride.
Vinyl acetate copolymer, the above-mentioned vinyl chloride / vinyl acetate copolymer resin having a content of polyvinyl alcohol unit of 1 to 30% by weight, polyester, partially saponified polyvinyl acetate, part of vinyl chloride-vinyl acetate copolymer or Completely saponified products, acrylic resins, polyurethane resins and the like, particularly preferred are polyvinyl acetal resins and vinyl chloride-vinyl acetate copolymers, and preferred polyvinyl acetal resins are polyvinyl formal resins, polyvinyl acetoacetal resins and polyvinyl butyral resins (effect: A crosslinked product comprising the above resin and a crosslinking agent is excellent in mold release properties, and is excellent in color density, sharpness, various durability, and non-embossability);

As described in JP-A-5-294076,
A polyvinyl acetal resin having a polyvinyl alcohol unit content of 10% by weight or more (or 10 to 50% by weight), a polyvinyl acetal resin having a degree of polymerization of 100 to 10,000, and the like.

In the formation of the image receiving layer, the various resins described above utilize their reactive sites (if there is no reactive site, they are applied to the resin) to obtain radiation, heat, moisture, and catalyst. Crosslinking or curing may be carried out. In that case, a radiation-active monomer such as epoxy or acrylic, or a cross-linking agent such as isocyanate can be used,
These monomers and crosslinking agents may be added as they are to the image receiving layer, or may be encapsulated in microcapsules.

The present invention is characterized in that a dye fixing body is contained in an image receiving layer. A preferred dye fixing body in the present invention is a metal source capable of forming a metal chelate with a post-chelating dye described later. When the image receiving layer contains a metal source and the ink layer of the ink sheet uses a post-chelating dye described later, the formed dye image exhibits high transfer density, high image storability, and particularly excellent effect of preventing bleeding. it can.

Examples of the metal source include inorganic or organic salts and metal complexes of metal ions, and among them, salts and complexes of organic acids are preferable. As the metal, the I-th of the periodic table
Monovalent and polyvalent metals belonging to Group VIII to VIII, among which Al, Co, Cr, Cu, Fe, Mg, M
n, Mo, Ni, Sn, Ti and Zn are preferred, and particularly Ni, Cu, Cr, Co and Zn are preferred.

As a specific example of the metal source, N
i ²⁺ , Cu ²⁺ , Cr ²⁺ , Co ²⁺ and Zn ²⁺ and an aliphatic salt such as acetic acid or stearic acid, or benzoic acid;
And salts of aromatic carboxylic acids such as salicylic acid.

The complex represented by the following general formula (A) is particularly preferable because it is stable and can be added to the image receiving layer and is substantially colorless.

[0098] Formula _{(I) [M (Q1) X (} Q2) Y (Q3) Z] P + (L -) P

In the general formula (A), M is a metal ion, preferably Ni ²⁺ , Cu ²⁺ , Cr ²⁺ , Co ²⁺ or Zn
Represents ²⁺ . Q1, Q2 and Q3 each represent a coordination compound capable of coordinating with the metal ion represented by M, and may be the same or different. These coordination compounds can be selected, for example, from the coordination compounds described in Chelate Science (5) (Nankodo). L ^-
Represents an organic anion group, and specific examples thereof include a tetraphenylboron anion and an alkylbenzenesulfonic acid anion. X represents 1, 2 or 3, Y represents 1, 2 or 0, and Z represents 1 or 0, which is a compound represented by the above general formula (A) in a tetradentate coordinate or 6 It is determined by whether it is a coordination coordinate or by the number of ligands of Q1, Q2 and Q3. P represents 1 or 2.
Specific examples of this type of metal source include those described in U.S. Pat. No. 4,987,049 and compound No. 5 described in Japanese Patent Application No. 5-1011008. 1 to 50 and the like.

The amount of addition of the metal source is usually preferably 5 to 80% by weight based on the binder of the image receiving layer.
70% by weight is more preferred. If the amount of the metal source in the image receiving layer is too large, the tint of the metal source appears in the color tone of the white background of the image receiving sheet, which is not preferable.

A releasing agent, an antioxidant, an ultraviolet absorber, a light stabilizer, a filler, a pigment and the like may be added to the image receiving layer. Further, a plasticizer, a heat solvent and the like may be added as a sensitizer.

The release agent can improve the releasability between the ink layer of the ink sheet and the image receiving layer of the image receiving sheet.
Examples of such release agents include silicone oils (including those referred to as silicone resins); solid waxes such as polyethylene wax, polypropylene wax, amide wax, Teflon powder, and microclostalin wax; fluorine compounds; Compounds or composites thereof, fluorine-based or phosphate-based surfactants; coupling agents; long-chain alkyl compounds; polyoxyalkyl polyols, and the like, among which silicone oil is preferred.

Silicone oils are classified into two types: those that are simply added (simple addition type) and those that are cured or reacted (curing reaction type). In the case of the simple addition type, it is preferable to use a modified silicone oil in order to improve the compatibility with the binder. Examples of the modified silicone oil include polyester-modified silicone resin (or silicon-modified polyester resin), acryl-modified silicone resin (or silicon-modified acrylic resin), urethane-modified silicone resin (or silicon-modified urethane resin), and cellulose-modified silicone resin ( Alternatively, a silicon-modified cellulose resin), an alkyd-modified silicone resin (or a silicon-modified alkyd resin), an epoxy-modified silicone resin (or a silicon-modified epoxy resin), and the like can be given.

Examples of the curing reaction type silicone oil include modified silicone oils having a reactive group as described below.

[0105]

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(C) Modified silicone having other reactive groups.

A modified silicone represented by the following general formula and defined by a reactive group: R ₆ .

[0108]

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R ₆ : isocyanate-modified silicone of —NCO, R ₆ : alcohol-modified silicone of —OH, R ₆ : carboxyl-modified silicone of —COOH

In the general formulas (structural formulas) (a) to (c), R _{1 to} R _{5 each} represent an organic group, which is mainly composed of a methyl group. It may be a phenyl group. l, m, and n each represent an integer of 1 or more appropriately set according to the molecular weight of the release resin. Further, the atomic groups of the l and m portions are randomly copolymerized.

Since the above silicones are cured by reaction, they are appropriately combined and used depending on the reaction mode. As the reaction mode, the modified silicone having an amino group or a hydroxyl group reacts with the modified silicone having an epoxy group, an isocyanate group or a carboxyl group, respectively.

Examples of the catalyst-curable type include the following two types of silicones (d) and (e).

(D) alcohol-modified silicone,
Dehydration polymerizable by two silicones.

[0114]

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(Catalyst: carboxylate such as titanate, zinc, iron, tin, etc.)

(E) A product comprising a vinyl-modified silicone and a vinyl-modified silicone in which a part of organic groups is -H.

[0117]

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(Catalyst: metal catalyst such as platinum)

The above-mentioned general formulas (d) to (e) (structures
In the formula), R₁~ R₆Represents an organic group, mainly methyl
Group, but an alkyl group other than a methyl group, or
It may be a phenyl group. However, in (e)
R for modified silicone₁~ R₆Any one of
Part is a vinyl group (-CH = CH₂), While the organic radical
Silicone or vinyl-modified silicone wherein part of is -H
R for₁~ R ₆Some of them are vinyl groups
In particular, those of vinyl-modified silicone have -H
In addition, R₁~ R₆At least one is a vinyl group
You. n, l, and m are appropriately set according to the molecular weight of the release resin.
Indicates an integer of 1 or more. Also, atoms in l and m
Groups are randomly copolymerized.

As another specific example of the vinyl-modified silicone, the following modified silicone can be mentioned.

[0121]

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As a preferred example, when the catalyst of the above formula (1) and the silicone of the formula (4) are mixed and used to cure the catalyst, the following formula is used.

[0123]

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When the above-mentioned polyfunctional silicone is used in combination, the main chain A contributes to the coating strength, the pendant B contributes to the releasability, and excellent coating properties and releasability are simultaneously achieved. You.

Examples of the silicone oil having a long-chain alkyl group (carbon number: n ≧ 16) as a part of the side chain include the following chain polymers (f) to (i).

(F) A release resin comprising a polyolefin chain polymer.

[0127]

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(G) A release resin comprising a polyester chain polymer.

[0129]

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In the above general formulas (structural formulas) of (f) to (i), R is-(CH ₂ ) _n -CH ₃ (n ≧ 1)
6) represents a long-chain alkyl group. At least one of R ₁ and R ₂ is a reactive group, and the others represent —H or an organic group of an alkyl group, and R ₃ and R ₄ represent an aliphatic or aromatic chain having a reactive group. n represents one or more integers appropriately set according to the molecular weight of the release resin.

The amount of the release resin (a) to (i) is 0.5 to 80% by weight based on the solid content of the layer to be contained.
Is preferred.

As antioxidants, JP-A-59-182 can be used.
No. 785, No. 60-130735, JP-A-1-127
The antioxidants described in each of JP-A Nos. 387 and 387 and known compounds for improving image durability in photographs and other image recording materials can be exemplified.

Examples of the ultraviolet absorber and the light stabilizer include, for example, JP-A-59-158287 and JP-A-63-74686.
Nos. 63-145089 and 59-196292
Nos. 62-229594 and 63-122596
No. 61-283595, JP-A-1-204788
And compounds known to improve the image durability of photographs and other image recording materials can be used. The weight ratio of the binder to the ultraviolet absorber (light stabilizer) is preferably from 1:10 to 10: 1, and more preferably from 2: 8 to 7: 3.

Examples of the filler include inorganic fine particles and organic resin particles. Examples of the inorganic fine particles include silica gel, calcium carbonate, titanium oxide, acid clay, activated clay, and alumina. Examples of the organic fine particles include resin particles such as fluororesin particles, guanamine resin particles, acrylic resin particles, and silicon resin particles. Can be mentioned. These inorganic / organic resin particles differ depending on the specific gravity, but are preferably added in an amount of 0.1 to 70% by weight.

Typical examples of the pigment include titanium white, calcium carbonate, zinc oxide, barium sulfate, silica, talc, clay, kaolin, activated clay, and acid clay.

Examples of the plasticizer include phthalate esters (eg, dimethyl phthalate, dibutyl phthalate, dioctyl phthalate, didecyl phthalate, etc.) and trimellitate esters (eg, octyl trimellitate, isononyl trimellitate) , Pyromellitic acid octyl ester and the like, pyromellitic acid esters such as octyl pyromellitic acid ester, and adipic acid esters. Since the excessive addition of the plasticizer deteriorates the storability of the image, the amount of the plasticizer added is usually
It is in the range of 0.1 to 30% by weight based on the binder of the image receiving layer.

A smooth back surface layer may be provided on the back surface of the image receiving sheet. When a smooth back surface layer is provided on the back surface of the image receiving sheet, the resin used preferably has low dye-dyeability. Specific examples of such a resin include an acrylic resin, a polystyrene resin, a polyolefin resin, a polyamide resin, polyvinyl butyral, polyvinyl alcohol, and a cellulose acetate resin. In addition, Japanese Patent Application Laid-Open
The amorphous polyolefin resin described in JP-A-186557 can also be used. In addition, curable resins obtained by curing polyvinyl butyral, melamine, cellulose, acrylic resin, and the like by means of chelate, isocyanate, irradiation with radiation, and the like are also preferable. Commercially available products include, for example, BR85, BR80, B
R113 (Mitsubishi Rayon), APL6509, 130A, 291S, 1 as amorphous polyolefin resin
50R (Mitsui Chemicals), ZEONEX 480, 2
50, 480S (manufactured by Nippon Zeon), 3000-1 (manufactured by Denki Kagaku Kogyo) for polyvinyl butyral resin, SMR-20H, SMR for polyvinyl alcohol resin
-20HH, C-20, C-10, MA-23, PA-
20, PA-15 (above manufactured by Shin-Etsu Chemical Co., Ltd.), cellulose acetate resins such as L-30 and LT-35 (both manufactured by Daicel Chemical Industries), and melamine resins such as Cymel 303 (manufactured by Mitsui Siad). However, the present invention is not limited to this.

In order to improve the suitability for automatic sheet feeding, at least one of the layers constituting the back surface of the image receiving sheet may contain an organic and / or inorganic filler. Specific examples include polyethylene wax, bisamide, nylon, acrylic resin, cross-linked polystyrene, silicone resin, silicone rubber, talc, calcium carbonate, titanium oxide, and the like, but are not particularly limited, and any can be used.

Among the above, the nylon filler is particularly preferred from the viewpoint of suppressing the wear of the paper feed rubber roller of the printer and the fluctuation of the frictional characteristic of the roller due to the transfer.
As the nylon filler, those having a molecular weight of 100,000 to 900,000 and being spherical and having an average particle diameter of 0.01 to 30 μm are preferable, and particularly having a molecular weight of 100,000 to 500,000 and an average particle diameter of 0.01 to Those having a thickness of 10 μm are more preferred. As the type of nylon filler, nylon 12 filler is more preferable than nylon 6 or nylon 66 because it has excellent water resistance and does not change its properties due to water absorption.

The nylon filler has a high melting point, is thermally stable, and has good oil resistance, chemical resistance, and the like, and thus is not easily dyed by a dye. Further, it has a self-lubricating property, a low coefficient of friction, and a molecular weight of 100,000 to 900,000 hardly wears and does not damage a mating material. Also,
The preferred average particle size is 0.1 to 30 μm. If the particle size is too small, the filler is hidden in the back surface constituting layer and does not perform a sufficient slip function, and if the particle size is too large, the protrusion from the back surface constituting layer becomes large, resulting in friction. It is not preferable because the coefficient is increased or the filler is missing. The amount of the filler is preferably in the range of 0.01 to 200 parts by weight based on 100 parts by weight of the resin of the layer to be added.

The center line average surface roughness Ra of the back layer surface is preferably 0.5 to 2.5 μm. Further, the average number of projections per unit area is preferably 2000 to 4500 / mm ² . As a method of imparting such properties, for example, by using a filler as described above,
It can also be formed by making the surface shape of the cooling roll at the time of resin extrusion coating the above-mentioned property and transferring the shape when the extruded resin is cooled.

An intermediate layer may be provided between the lubricating back layer and the support for the purpose of increasing the adhesive strength. As a preferred embodiment of the intermediate layer, an intermediate layer having a reaction-curable resin is provided. As the reaction-curable resin, it is preferable to use a thermosetting resin and / or an ionizing radiation-curable resin as described in JP-A-6-255276.

An intermediate layer having the same structure may be provided between the support and the image receiving layer.

In the present invention, the ink sheet is formed at least from a support and an ink layer provided thereon.
As the heat diffusible dye used in the ink layer, basically any conventionally known dye can be used, and there is no limitation at all. In the present invention, a dye fixing body is contained in the image receiving layer. Since the ink layer is used in combination with an image receiving sheet, the ink layer contains a heat-diffusible dye precursor. A preferred dye precursor in the present invention is a post-chelating dye.

The support for the ink sheet is not particularly limited as long as it has good dimensional stability and can withstand the heat at the time of recording with a thermal head, and any known support can be used.

Examples of the binder for the ink layer include cellulose adducts, cellulose resins such as cellulose esters and cellulose ethers, polyvinyl acetal resins such as polyvinyl alcohol, polyvinyl formal, polyvinyl acetoacetal and polyvinyl butyral, polyvinyl pyrrolidone, and polyvinyl acetate. , Polyacrylamide, styrene resin, poly (meth) acrylic acid ester, poly (meth) acrylic acid, vinyl resin such as (meth) acrylic acid copolymer, rubber resin, ionomer resin, olefin resin, polyester Resins and the like can be mentioned. Among these resins, polyvinyl butyral, polyvinyl acetoacetal, or cellulosic resins having excellent storage stability are preferable.

The following resins can be further used as a binder for the ink layer.

The reaction product of an isocyanate and a compound having active hydrogen selected from polyvinyl butyral, polyvinyl formal, polyester polyol and acrylic polyol described in JP-B-5-78437, wherein the isocyanate is diisocyanate or The reaction product in the amount of 10 to 200 parts by weight with respect to 100 parts by weight of the reaction product as a triisocyanate and the compound having active hydrogen; intramolecular hydroxyl groups of a natural and / or semi-synthetic water-soluble polymer Examples of the organic solvent-soluble polymer obtained by esterifying and / or urethane, natural and / or semi-synthetic water-soluble polymers include α-glucose α-1,
Starch which is a polymer of 4-glucoside bond, water-soluble derivative of cellulose which is a polymer of β-1,4-glucoside bond, β-1,4- of pyranose ring
It is made from alginic acid, a polymer of glucosidic bonds, maltotriose, a trimer of glucose, pullulan, a water-soluble polysaccharide repeatedly linked by 1,6 bonds of α-D-1,6-glucose, and sucrose. Dextran, which is a polymer having D-glucopyranose as a unit, D-
Curdlan or the like, in which glucose is a linear β-1,3-glucan in which β-glucosidic bonds are formed by 1,3 bonds;

Cellulose acetate having a degree of acetylation of at least 2.4 and a total degree of substitution of at least 2.7 described in JP-A-3-264393; polyvinyl alcohol (Tg = 85)
° C), polyvinyl acetate (Tg = 32 ° C), vinyl chloride /
Vinyl resins such as vinyl acetate copolymer (Tg = 77 ° C.),
Polyvinyl acetal resins such as polyvinyl butyral (Tg = 84 ° C.) and polyvinyl acetoacetal (Tg = 110 ° C.), polyacrylamide (Tg = 165 ° C.)
Such as vinyl resins and aliphatic polyesters (Tg = 130
C) and other polyester resins;

The reaction product of isocyanates described in JP-A-7-52564 with polyvinyl butyral containing 15 to 40% by weight of a vinyl alcohol moiety, wherein the isocyanates are diisocyanates or triisocyanates. The above reaction product, specifically, paraphenylene diisocyanate, 1-chloro-
2,4-phenylene diisocyanate, 2-chloro-
1,4-phenylene diisocyanate, 2,4-toluene diisocyanate, 2,6-toluene diisocyanate, hexamethylene diisocyanate, 4,4'-biphenylene diisocyanate, 4,4 ', 4 "-trimethyl-3,3', 2- Triisocyanate-2,4,6-
Triphenyl cyanurate and the like;

A phenyl isocyanate-modified polyvinyl acetal resin of the formula I described in JP-A-7-32742;
JP-A-6-155935, one type of isocyanate-reactive cellulose or isocyanate-reactive acetal resin, isocyanate-reactive acetal resin, isocyanate-reactive vinyl resin, isocyanate-reactive acrylic resin, isocyanate-reactive phenoxy resin and A cured product of a composition containing one resin selected from isocyanate-reactive styrene resins and a polyisocyanate compound;

Polyvinyl butyral resin (preferably having a molecular weight of at least 60,000, a glass transition temperature of at least 60 ° C., more preferably at least 70 ° C. and at most 110 ° C.)
%, Preferably 15 to 30%); Examples of the acryl-modified cellulose resin and the cellulose resin include cellulose resins such as ethyl cellulose, hydroxyethyl cellulose, ethyl hydroxycellulose, hydroxypropyl cellulose, methyl cellulose, cellulose acetate, and cellulose butyrate acetate. (Preferably ethylcellulose), examples of the organic solvent used when the above-mentioned cellulose resin is modified with an acrylic resin include, for example, ester solvents such as methyl formate, ethyl formate, ethyl acetate and butyl acetate, acetone, methyl ethyl ketone, and methyl isobutyl. Ketone,
Examples thereof include ketone solvents such as cyclohexanone and isophorone, hydrocarbon solvents such as toluene, benzene, and xylene, and ether solvents such as n-butyl ether. The cellulose resin is preferably used at a concentration of about 5 to 50% by weight. .

One of the above-mentioned various binders can be used alone, or two or more of them can be used in combination.

The post-chelating dye contained in the ink layer is not particularly limited as long as it can be thermally transferred, and various known compounds can be appropriately selected and used. More specifically, for example, JP-A-59-78893, JP-A-59-109349, and Japanese Patent Application No. 2-2133.
No. 03, No. 2-214719, No. 2-2
For example, cyan dyes, magenta dyes, and yellow dyes described in JP-A-03742 can be used.

Among the above-mentioned dyes, it is preferable to use a methine dye which can form a bidentate chelate with a metal source, since the object of the present invention is more effectively exhibited. Examples of such a dye include a dye represented by the following general formula (1).

[0156]

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In the formula, X represents an atomic group having at least a bidentate chelate-forming group or atom, Y represents an atomic group necessary for forming an aromatic carbocyclic or heterocyclic ring,
₁ , R ₂ and R ₃ each represent a hydrogen atom, a halogen atom or a monovalent substituent. n represents 0, 1 or 2. Y is preferably an atomic group forming a 5- to 6-membered aromatic carbocyclic or heterocyclic ring, and the ring may further have a substituent.

X is particularly preferably represented by the following general formula (2).

[0159]

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In the formula, Z represents an atomic group necessary for forming an aromatic nitrogen-containing heterocyclic ring substituted with at least one group containing a chelatable nitrogen atom.

Specific examples of the ring include benzene, pyridine, pyrimidine, furan, thiophene, thiazole, imidazole, naphthalene and the like. These rings may further form a condensed ring with another carbon ring (such as a benzene ring) or a heterocyclic ring (such as a pyridine ring).

The substituents on the ring include an alkyl group, an aryl group, an acyl group, an amino group, a nitro group, a cyano group,
Examples thereof include an acylamino group, an alkoxy group, a hydroxy group, an alkoxycarbonyl group, and a halogen atom, and these groups may be further substituted.

The halogen atom represented by R ₁ , R ₂ and R ₃ is a fluorine atom, a chlorine atom and the like, and the monovalent substituent is an alkyl group, an alkoxy group, a cyano group and an alkoxycarbonyl group. No.

As X =, those represented by the following general formulas (3) to (6) are particularly preferred.

[0165]

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In the formula, R ₄ and R ₅ are each a hydrogen atom, a halogen atom (a fluorine atom, a chlorine atom, a bromine atom, etc.) or a monovalent substituent (an alkyl group, an aryl group, an acyl group, an amino group, a nitro group). Group, cyano group, acylamino group, alkoxy group, hydroxyl group, alkoxycarbonyl group, etc.)
Represents

Specific examples of the compounds are shown below, but the present invention is not limited thereto.

[0168]

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[0169]

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[0170]

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[0171]

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The content of these post-chelating dyes cannot be unconditionally determined from the properties of the respective dyes, the solubility in the binder, the purpose of use, etc., but is usually 10 to 80% by weight of the total weight of each dye-containing region. Used in%.

In the present invention, various additives may be appropriately added to the ink layer in addition to the above-mentioned components. Examples of the additives include silicone resin, silicone oil (reaction curing type is also possible), silicone-modified resin, fluororesin, surfactant, and release compounds such as waxes, metal fine powder, silica gel, and metal as described above. Fillers such as oxides, carbon black, and resin fine powder, and curing agents (for example, radiation-active compounds such as isocyanates, acryls, and epoxies) that can react with a binder component can be given.

In the present invention, the ink sheet is not limited to the two-layer structure including the support and the ink layer, and other layers may be formed. For example, an overcoat layer may be provided on the surface of the ink layer for the purpose of preventing fusion with the image receiving layer and offset (blocking) of the dye.

Further, the support of the ink sheet may have a subbing layer for the purpose of improving the adhesiveness of the ink layer to the binder and preventing transfer and dyeing of the sublimable dye to the support side. Further, a sticking prevention layer may be provided on the back surface of the support (on the side opposite to the ink layer) for the purpose of preventing fusion or sticking of the head to the support and wrinkling of the ink sheet. The thickness of the overcoat layer, the undercoat layer and the anti-sticking layer is usually 0.1 to
1 μm.

The ink sheet is prepared by dispersing or dissolving the various components for forming the ink layer in a solvent to prepare a coating liquid for forming an ink layer, and applying the coating liquid on the surface of the ink sheet support, for example, by gravure printing. It can be manufactured by coating and drying in a system. The thickness of the ink layer to be formed is usually from 0.2 to 10 μm, preferably from 0.3 to 3 μm.

In the ink layer of the present invention, 5 is used as a sensitizer.
A low molecular weight substance having a melting point of 0 to 150 ° C may be contained. If the melting point is lower than 50 ° C., the sensitizer easily migrates to the surface of the ink layer, causing problems such as blocking. On the other hand, if the melting point is higher than 150 ° C., the sensitizing effect is rapidly lowered, which is not preferable.

The molecular weight of the sensitizer is preferably in the range of 100 to 1500. If the molecular weight is less than 100, the melting point is 50
° C or higher, while the molecular weight is 1
If it exceeds 500, the sharpening of the melting of the sensitizer at the time of thermal transfer is lost and the sensitizing effect becomes insufficient, which is not preferable.

The sensitizer is preferably used in a proportion of 1 to 100 parts by weight per 100 parts by weight of the binder forming the ink layer. If the amount is less than 1 part by weight, it is difficult to obtain a satisfactory sensitizing effect, while if it exceeds 100 parts by weight, the heat resistance of the ink layer is undesirably reduced.

The sensitizer as described above may be any known low molecular weight substance as long as it has a melting point of 50 to 150 ° C., but is preferably a thermoplastic resin oligomer such as a polyurethane oligomer, a polystyrene oligomer, or a polyester. Oligomer, polyacryl oligomer, polyethylene oligomer, polyvinyl chloride oligomer, polyvinyl acetate oligomer, ethylene / vinyl acetate copolymer oligomer, ethylene acrylic copolymer oligomer, polyoxyethylene oligomer, polyoxypropylene oligomer, polyoxyethylene propylene oligomer And various fatty acids such as myristic acid, palmitic acid, margaric acid, stearic acid, arachiic acid, and montanic acid, caproic acid amide, caprylic acid amide, and lauric acid amide. Fatty acid amides, such as, stearic acid amide, oleic acid amide, eicosenoic acid amide, etc., fatty acid amides such as methyl behenate, pentadecyl palmitate, hexacosyl stearate, [1,4-phenylenebis (methylene)] carbamic acid bisdimethyl ester, etc. And other aromatic compounds such as 1,4-dicyclohexylbenzene, benzoic acid, aminobenzophenone, dimethyl terephthalate, fluoranthene, phenols, naphthalenes and phenoxys, and various waxes.

In the present invention, the image receiving sheet and / or the ink sheet may have an antistatic function. In order to provide an antistatic function, a conventionally known technique can be used. That is, conductive substances such as metals, metal oxides, and fine powders of carbon, and organic compounds called “antistatic agents” (cationic, anionic, amphoteric, nonionic surfactants, polysiloxanes, etc.) System), electron-conductive inorganic fine powder (fine powder such as titanium oxide, zinc oxide, tin oxide, indium oxide, etc.) mixed with impurities and baked to disturb the crystal lattice and enhance electron conductivity. A well-known conductive substance such as one subjected to doping treatment) can be used.

The conductive substance as described above may be contained in at least one of the constituent layers of the image receiving sheet and / or the ink sheet, or at least one of the conductive layers coated with a paint containing the conductive substance. A layer may be formed. Of course, the combination is also preferable.

When the above conductive material is used for the conductive layer, the conductive paint can be adjusted by a usual method. Preferably, the antistatic agent is used in the form of an alcohol solution or an aqueous solution, The inorganic fine powder is used as it is, and is adjusted by dissolving or dispersing the former in an organic solvent solution of the resin to be a binder, and dispersing the latter in the latter.

The resin to be used as a binder for the conductive paint is a thermosetting resin such as a thermosetting polyacrylate resin, a polyurethane resin, or the like, or a polyvinyl chloride resin, a polyvinyl butyral resin, a polyester resin, or the like. It is preferable to use a suitable thermoplastic resin. Note that it is preferable to determine the ratio of the binder to the conductive substance so that the surface resistivity of the conductive layer after coating and drying (in some cases, after curing) is 1 × 10 ¹⁰ Ωcm or less.

The adjusted conductive paint can be applied by a usual coating method, for example, coating with a blade coater, gravure coater or the like, spray coating or the like.

In the case where a conductive layer is provided on the core material to have a charge treatment function, an aqueous solution of an antistatic agent is applied, or the above-mentioned electron conductive inorganic fine powder is mixed with a synthetic resin emulsion.
It is preferable to disperse or dissolve in a water-based paint such as an aqueous solution of a synthetic rubber latex or an aqueous solution resin to form a dry coating film. Emulsions such as polyacrylate resin resins and polyurethane resins as synthetic resin emulsions, methyl methacrylate-butadiene, rubber latexes such as styrene-butadiene as synthetic rubber latex, polyvinyl alcohol resins, polyacrylamide resins as aqueous solutions of water-soluble resins, An aqueous solution such as starch can be exemplified.
Alternatively, an aqueous solution of an antistatic agent may be more easily spray-coated.

In the present invention, when an image is formed using a post-chelating dye and a metal source, it is preferable to provide a heating step after transferring the dye, and to perform a heat treatment on the obtained transferred image. It is. The method of heat treatment is a known method, that is, a hot plate through a thin film material,
A heat roller, a thermal head (which may be the same as or different from that for dye transfer) or the like can be used, and there is no particular limitation.

[0188]

Next, the present invention will be described more specifically with reference to examples. In the following examples, “parts” means “parts by weight”.

Example 1 (Formation of Film) (Film 1) PET and polytetramethylene glycol (hereinafter PTMG, molecular weight 400
PET-PTMG copolymer 1 produced by adding PTMG at the time of polymerization of PET so that the weight ratio with 0) becomes 1: 1.
wt%, polyethylene terephthalate (PET) resin 90 wt%, and polystyrene (PS) resin (amorphous, Styron 666, manufactured by Asahi Kasei Corporation) 9 wt%
%, And supplied to a vented twin-screw extruder heated to 270 to 300 ° C., and formed into a sheet from an extruded T-die while being degassed and dried by a vacuum pump.

Further, the sheet was cooled and solidified by a cooling drum having a surface temperature of 25 ° C., led to a group of rolls heated to 80 to 100 ° C., stretched three times in the machine axis direction, and cooled by a group of rolls of 25 ° C. . Subsequently, the longitudinally stretched film was guided to a tenter while holding both ends of the film with clips, and was transversely stretched 3.6 times in a direction perpendicular to the machine axis direction in an atmosphere heated to 115 ° C. Thereafter, heat fixation at 220 ° C. is performed in a tenter, and the film is gradually cooled, and then cooled to room temperature.
A μm film 1 was obtained.

(Film 2) In film 1, PS
Was replaced with polypropylene (hereinafter referred to as PP) to obtain a film 2 having a thickness of 100 μm in the same manner.

(Film 3) In film 1, PS
Instead of syndiotactic polystyrene (hereinafter SY)
N-PS) resin (Zarek A100, manufactured by Idemitsu Petrochemical Co., Ltd.) was used, and a film 3 having a thickness of 100 μm was obtained in the same manner.

(Film 4) As a raw material of the A layer, P
The weight ratio of ET to PTMG (molecular weight 4000) is 1: 1
1 wt% of a PET-PTMG copolymer produced by adding PTMG during the polymerization of PET,
wt.% and 9 wt% of a PS resin (amorphous, Styron 666, manufactured by Asahi Kasei Corporation) were used.
A material obtained by vacuum drying at 80 ° C. for 3 hours is used. As a raw material of the layer B, a mixed chip of 99% by weight of PET and 1% by weight of calcium carbonate (Softon 3200 manufactured by Shiraishi Calcium Co., Ltd.) is vacuum dried at 180 ° C. for 3 hours. These raw materials are supplied to separate vent-type twin-screw extruders and kneaded, and a three-layer structure (B / A /
Layer A and layer B were laminated and extruded using a co-extrusion die as shown in B). Further, the sheet is cooled and solidified by a cooling drum having a surface temperature of 25 ° C., guided to a group of rolls heated to 80 to 100 ° C., longitudinally stretched three times in the machine axis direction.
Of the roll group. Subsequently, the longitudinally stretched film was guided to a tenter while gripping both ends of the film with clips, and was heated at 115 ° C.
2. in a direction perpendicular to the machine axis direction in an atmosphere heated to
The film was stretched 6 times in the transverse direction. Thereafter, heat fixation at 220 ° C. is performed in a tenter.
A film 4 of 0 μm was obtained. The thickness configuration was 5/90/5.

(Film 5) P
The weight ratio of ET to PTMG (molecular weight 4000) is 1: 1
1 wt% of a PET-PTMG copolymer produced by adding PTMG during the polymerization of PET,
wt.% and 5 wt% of a SYS-PS resin (Zarek A100, manufactured by Idemitsu Petrochemical Co., Ltd.)
As a raw material of the layer B, 99 wt% of PET and 1 wt% of calcium carbonate (Softon 3200 manufactured by Shiraishi Calcium Co., Ltd.)
% Mixed chips were vacuum-dried at 180 ° C. for 3 hours, and these raw materials were supplied to separate vented twin-screw extruders and kneaded, and the three layers of the A layer were an inner layer and the B layer were an outer layer. The layer A and the layer B were laminated and extruded using a co-extrusion die so as to have a configuration (B / A / B). Further, the sheet is cooled and solidified by a cooling drum having a surface temperature of 25 ° C.
And stretched three times longitudinally in the machine axis direction, and cooled with a roll group at 25 ° C. Subsequently, the longitudinally stretched film was guided to a tenter while holding both ends of the film with clips, and was transversely stretched 3.6 times in a direction perpendicular to the machine axis direction in an atmosphere heated to 115 ° C. Then 220 ° C in a tenter
Was heat-fixed, uniformly cooled, and then cooled to room temperature to obtain a film 5 having a winding thickness of 100 μm. The thickness configuration is 5 /
90/5.

(Film 6) In the film 5, the amounts of PET and SYS-PS as the raw materials of the layer A were 90 wt.
% And 9 wt%, and a film 6 having a winding thickness of 100 μm was prepared in the same manner as the film 5. The thickness configuration was 5/90/5.

(Film 7) In the film 5, the amounts of PET and SYS-PS as the raw materials of the layer A were 89 wt.
%, And a film 6 having a take-up thickness of 100 μm was prepared in the same manner as the film 5 except that the content was 10% by weight. The thickness configuration was 5/90/5.

(Film 8) In the film 5, the amounts of PET and SYS-PS as the raw materials of the layer A were 88 wt.
%, 11 wt%, and the amounts of PET and calcium carbonate in the B layer were changed to 95 wt% and 5 wt%, respectively, and a film 8 having a winding thickness of 100 μm was prepared in the same manner as the film 5 except that the extrusion conditions were adjusted. did. The thickness configuration is 4 /
92/4.

(Film 9) In the film 8, the amounts of PET and SYS-PS as the raw materials for the layer A were 86 wt.
% And 13 wt%, and a film 9 having a winding thickness of 100 μm was prepared in the same manner as the film 7. The thickness configuration was 4/92/4.

(Film 10) As a raw material of the layer A, PE
T resin 91 wt% and SYS-PS resin (Zarek A1
00, manufactured by Idemitsu Petrochemical Co., Ltd.) except that a mixture of 9 wt% was used, and the winding thickness was 10
A film 10 having a thickness of 0 μm was prepared. The thickness configuration is 5/90
/ 5.

(Film 11) As a raw material of the layer B, PE
The same procedure as for film 5 was used, except that the T chip was vacuum dried at 180 ° C. for 3 hours.
m was obtained. The thickness configuration was 5/90/5.

(Preparation of Ink Sheet 1) As a support,
Heat-resistant protective layer on one side (SP-712, manufactured by Dainichi Seika Co., Ltd.)
A 6 μm-thick polyethylene terephthalate film (Lumirror 6CF531 manufactured by Toray Industries, Inc.) is coated with a yellow, magenta, and cyan ink layer and a heat treatment layer having the following compositions by a gravure method on the back surface of the protective layer. 1 (dry coating amount: 1.1 g / m ² ), the yellow, magenta, and cyan ink layers and the heat-treated layer are shown in FIG.
Ink sheets formed in the order shown in (a) (hereinafter referred to as “sequential”) were obtained.

Yellow ink layer Post-chelate dye Y-1 30 parts Polyvinyl acetal (Denka Butyral KY-24, manufactured by Denki Kagaku Kogyo KK) 55 parts Polymethyl methacrylate (Reseda GP, manufactured by Toa Gosei Chemical Industry Co., Ltd.) -305) 10 parts Urethane-modified silicone oil (Daiomer SP-2105 manufactured by Dainichi Seika Kogyo Co., Ltd. 5 parts

Magenta ink layer The following post-chelating dye M-1 30 parts Polyvinyl acetal (Denka Butyral KY-24, manufactured by Denki Kagaku Kogyo Co., Ltd.) 55 parts Polymethyl methacrylate (Toa Gosei Chemical Industry Co., Ltd., Reseda GP -305) 10 parts Urethane-modified silicone oil (Daioma Seika Kogyo Co., Ltd., Dialoma SP-2105) 5 parts

Cyan Ink Layer 30 parts of the following post-chelating dye C-1 polyvinyl acetal (Denka Butyral KY-24, manufactured by Denki Kagaku Kogyo Co., Ltd.) 55 parts Polymethyl methacrylate (Toa Gosei Chemical Industry Co., Ltd., Reseda GP -305) 10 parts Urethane-modified silicone oil (Daioma Seika Kogyo Co., Ltd., Dialoma SP-2105) 5 parts

[0205] heat treatment layer ^{_{Ni 2+ (NH 2 COCH 2 NH}} 2) 3 · 2B (C 6 H 5) 4 - ( metal source (MS-1)) 1 part polyvinyl acetal (Denki Kagaku Kogyo Co., Ltd., Denka Butyral KY-24) 59 parts Polymethyl methacrylate (manufactured by Toagosei Chemical Industry Co., Ltd., Reseda GP-305) 20 parts Urethane-modified silicone oil (manufactured by Dainichi Seika Industry Co., Ltd., dialomer SP-2105) 20 parts

[0206]

Embedded image

(Preparation of Image Receiving Sheet) As a support of the image receiving sheet, the films 1 to 9 prepared above were used, and on one surface thereof, an anchor layer having the following composition and an image receiving layer were applied in this order.
An anchor layer having a thickness of 0.2 μm and an image receiving layer having a thickness of 4 μm were formed to obtain an image receiving sheet.

Anchor Layer Polyvinyl Butyral (Eslec BL-1 manufactured by Sekisui Chemical Co., Ltd.) 90 parts Isocyanate (Coronate HX manufactured by Nippon Polyurethane Industry Co., Ltd.) 10 parts

Image receiving layer Polyvinyl butyral (Eslec BX-1 manufactured by Sekisui Chemical Co., Ltd.) 65 parts Metal source (MS-1) 30 parts Polyester modified silicon (X-24-8300 manufactured by Shin-Etsu Chemical Co., Ltd.) 5 copies

(Formation of Step Pattern Image) The image receiving layer portion of the thermal transfer image receiving sheet and the ink layer portion of the ink sheet created by the above procedure were superimposed, and the resolution was 12 dots / mm.
A yellow, magenta, cyan, and neutral (three-color superimposed) step pattern that is in pressure contact with a thermal head having an average resistance value of 3100Ω by a platen roll and sequentially increases in an applied energy range of 5 to 80 mJ / mm ² is fed at a feeding speed of 10 msec / line. Under the conditions described above, the dye was transferred onto the image receiving layer by heating from the back side of the ink layer. Next, the heat-treated layer and the image-receiving sheet on which the dye was transferred were pressed against the same thermal head and platen roll, and the applied energy was 50 mJ.
/ Mm ² , and a feed rate of 8.8 msec / line, a heat treatment was performed by heating from the back side of the heat treatment layer.

(Formation of Solid Black Pattern Image)
80mJ / m applied energy for each of magenta and cyan colors
The process was performed in the same manner as the formation of the step pattern image, except that the printing was performed over the entire printing area under the conditions of m ² and a feeding speed of 10 msec / line.

(Formation of Intermediate Gray Pattern Image) Each of the yellow, magenta, and cyan colors transmits an applied energy of 40 m.
The procedure was the same as that for forming the step pattern image, except that the printing was performed over the entire print area under the conditions of J / mm ² and a feed speed of 10 msec / line. The following measurements and evaluations were performed on the obtained samples.

(Measurement of apparent specific gravity)
It was cut into a square of mx 100 mm, and a thickness of at least 10 points was measured using a dial gauge (No. 2109-10 manufactured by Mitoyo Seisakusho Co., Ltd.) with a measuring element (No. 7002) with a diameter of 10 mm attached. Calculate the average value d (μm).
This film was weighed with a direct reading balance and weighed w.
Read (g) to the ^{nearest 10-4} g. At this time, apparent specific gravity = w / d × 100.

(Evaluation of Sensitivity) Each Y,
M, C, and neutral patches are measured using a reflection densitometer (X-RIT).
It was measured by X-RITE310 manufactured by E Company.

(Evaluation of print curl) In the A4 size, the image receiving sheets before and after outputting the solid black pattern were placed on a flat surface, and the height of each of the four corners was measured to measure the degree of curl. . It is preferably at most 10 mm or less.

：: Almost no curl (５5 mm) Δ: Slightly curled but at a level that can withstand practical use (〜１０10 m)
m) ×: Many curls, impractical (10 mm or more) ××: Severe curls, not practical (30 mm)
~)

(Evaluation of Cushioning Property) The presence or absence of image omission was evaluated in the sample on which the intermediate gray pattern was printed. If the cushioning property is poor, when foreign matter such as dust and dust is present on the surface of the image receiving layer, the surface of the ink layer or in the image receiving layer, the shape is not printed and color loss occurs in its shape.

：: None at all △: Slightly generated but at a level that can withstand practical use ×: Many omissions, impractical ××: Severe omission, not acceptable for practical use

(Evaluation of Folding Wrinkle Resistance) The image receiving sheet before printing was cut into a strip having a length of 5 cm and a width of 1 cm, and was cut to a diameter of 5 cm.
The sample was stretched again by winding it around a glass rod having a diameter of 10 cm, and the state of the wrinkles generated on the surface was observed using a stereoscopic microscope.

：: Not at all △: Slightly generated but at a level that can withstand practical use X: Folding wrinkles are observed, making it unpractical XX: Severe wrinkles and cannot be put to practical use

(Evaluation of surface glossiness) V manufactured by Nippon Denshoku Industries Co., Ltd.
The reflectance at a measurement angle of 60 degrees was measured using GS-1001DP.

(Measurement of Image Lightfastness) Each portion of the step pattern near the density of 1.0 for each of Y, M, and C was measured with a xenon fade meter (WEL-, manufactured by Suga Test Instruments Co., Ltd.).
6X-HC-Ec, the light source illuminance was 70,000 lux), and the residual ratio of the concentration was determined from the concentrations after the exposure for 14 days and before the exposure. The residual ratio is preferably 70% or more. Table 1 shows the obtained results.

[0223]

[Table 1]

(Example 2) In the production of the film of Example 1, the conditions such as the extrusion conditions and the stretching conditions were changed, and films having a winding thickness of 50 μm and 60 μm were produced. After the same anchor layer and image receiving layer as those in Example 1 were applied to those films, the surface on which the image receiving layer was not applied and the following three types of core materials were bonded by a dry lamination method.
Further, a surface (reverse surface) opposite to the surface on which the core material is bonded.
Then, the films shown in Table 2 were adhered by a dry lamination method to prepare an image receiving sheet. The obtained image receiving sheet was evaluated in the same manner as in Example 1 except that the following evaluation was performed as the cushioning property evaluation. Table 2 shows the results.

Core material 1: high-quality paper having a basis weight of 120 g / m ² Core material 2: PET film having a thickness of 125 μm (S-10
0, manufactured by Diafoil Hoechst Co., Ltd. Core 3: PET film (W-10 having a thickness of 125 μm)
0, manufactured by Diafoil Hoechst Co., Ltd.)

(Evaluation of Cushioning Property) In the low density region of the step pattern, the state of image unevenness was observed.
If the cushioning property of the sample on the image receiving paper side is poor, irregularities on the surface of the core material are picked up, and so-called formation unevenness is observed.

：: Not at all △: Slightly generated but at a level that can withstand practical use ×: Many irregularities, impractical XX: Severe irregularities, not practical

[0228]

[Table 2]

(Example 3) An anchor layer and an image receiving layer similar to those in Example 1 were applied to the film having a winding thickness of 50 µm produced in Example 2, and then the surface to which the image receiving layer was not applied. Were laminated by a dry lamination method to prepare an image receiving sheet. The obtained image-receiving sheet was evaluated in the same manner as in Example 2, except that the following evaluation was performed as the evaluation of environmental curl. Table 3 shows the results.

Core 1: PET film 125 μm thick (S-100, manufactured by Diafoil Hoechst Co.) Core 2: Dimensionally stable paper 125 μm thick, AL-120F
(Awa Paper Co., Ltd.) (Paper mixed with aluminum hydroxide fiber) Core 3: Dimensionally stable paper with a thickness of 125 μm, FB (Awa Paper Co., Ltd.) (Paper mixed with thermoplastic resin fiber) Core material 4: Moisture proof paper having a thickness of 125 μm (Lintech Co., Ltd.)
Core material 5: 125 μm thick inorganic paper (Lintec Co., Ltd.)
Made)

(Evaluation of environmental curl) In an A4 size, the image-receiving sheet before printing was humidified in an atmosphere of 23 ° C. and 55% RH for 3 days, and when the sheet was placed on a flat place, the raised height of each of the four corners was raised. After the measurement, the image-receiving sheet was heated at 23 ° C. and 80% R
When the humidity was further adjusted for 3 days in an atmosphere of H, 23 ° C. and 20% RH, the same height was measured, and the difference was used to evaluate the degree of environmental curl. It is preferably at most 10 mm or less.

：: almost no curl (〜5 mm) Δ: slightly curled but at a level that can withstand practical use (〜１０10 m)
m) ×: Many curls, impractical (10 mm or more) ××: Severe curls, not practical (30 mm)
~)

[0233]

[Table 3]

[0234]

According to the present invention, it is possible to provide a thermal transfer recording method which enhances adhesion to a thermal head or the like, has no image defects, is excellent in sensitivity and image storability, and an image receiving sheet used therefor.

[Brief description of the drawings]

FIG. 1 is a plan view showing an example of an embodiment of an ink layer and a heat treatment layer provided on an ink sheet used in a method of the present invention.

[Explanation of symbols]

 Reference Signs List 1 reheat treatment layer 2Y area containing yellow dye 2M area containing magenta dye 2C area containing cyan dye 3 ink sheet support

Claims (21)

[Claims] An ink sheet having at least one ink layer containing a heat-diffusible dye precursor on a support, and a dye capable of forming a dye by reacting with the dye precursor on the support. Thermal transfer in which an image-receiving sheet having at least one image-receiving layer containing a fixing member is superposed such that the image-receiving layers are opposed to each other, heated imagewise, and the dye precursor is transferred to the image-receiving layer to form an image. In the recording method, the support of the image receiving sheet is a composite film of at least two or more layers including a first layer composed of a composition containing a polyester resin as a main component and a layer having an apparent specific gravity higher than the first layer. Consisting of, the apparent specific gravity of the composite film is 0.6 to
1.1. A thermal transfer recording method, wherein the method is 1.1. 2. The thermal transfer recording method according to claim 1, wherein the first layer of the composite film comprises a composition of a polyester resin and a styrene polymer having a syndiotactic structure. 3. The composite film according to claim 1, wherein the first layer comprises a composition of a polyester resin, a styrene polymer having a syndiotactic structure, and a polyester polyether copolymer. Thermal transfer recording method. 4. The composite film according to claim 1, wherein the first layer has an apparent specific gravity of 0.3 to 1.0.
4. The thermal transfer recording method according to 2 or 3. 5. The method according to claim 1, wherein the layers other than the first layer of the composite film are:
5. The thermal transfer recording method according to claim 1, wherein the layer is made of a composition containing a polyester resin as a main component. 6. The composite film according to claim 1, wherein a first layer and a layer made of a composition mainly composed of a polyester resin are provided on at least one surface of said first layer. The thermal transfer recording method according to 1, 2, 3, 4 or 5. 7. The thermal transfer recording method according to claim 6, wherein the layer provided on at least one surface of the first layer of the composite film is a layer substantially not containing voids (voids). 8. The thermal transfer recording method according to claim 1, wherein said composite film is produced by simultaneous extrusion and subsequent biaxial stretching. 9. A thermal transfer recording method, wherein the support of the image receiving sheet is formed by laminating the composite film according to claim 1 on at least one surface of a core material. 10. The thermal transfer recording method according to claim 9, wherein the core material is made of synthetic paper containing fiber paper or plastic film. 11. The thermal transfer recording method according to claim 1, wherein the dye precursor is a chelatable compound, and the dye fixing body is a metal ion-containing compound. Method. 12. The ink layer surface of an ink sheet having at least one ink layer containing a heat-diffusible dye precursor on a support, and a dye capable of forming a dye by reacting with the dye precursor on the support. At least one image-receiving layer containing a fixing member;
An image receiving sheet used in a thermal transfer recording method for forming an image by superimposing image receiving layer surfaces of image receiving sheets having layers so as to face each other and heating imagewise to transfer the dye precursor to the image receiving layer. The support of the sheet comprises at least two or more composite films including a first layer composed of a composition containing a polyester-based resin as a main component and a layer having an apparent specific gravity higher than that of the first layer; Wherein the apparent specific gravity is 0.6 to 1.1. 13. The image receiving sheet according to claim 12, wherein the first layer of the composite film comprises a composition of a polyester resin and a styrene polymer having a syndiotactic structure. 14. The composite film according to claim 12, wherein the first layer comprises a composition of a polyester resin, a styrene polymer having a syndiotactic structure, and a polyester polyether copolymer. Image receiving sheet. 15. The composite film according to claim 1, wherein the first layer has an apparent specific gravity of 0.3 to 1.0.
15. The image receiving sheet according to 2, 13, or 14. 16. The image receiving apparatus according to claim 12, wherein layers other than the first layer of the composite film are layers composed of a composition containing a polyester resin as a main component. Sheet. 17. The composite film according to claim 1, wherein a first layer and a layer made of a composition containing a polyester resin as a main component are provided on at least one surface of said first layer. The image receiving sheet according to 12, 13, 14, 15 or 16. 18. The image receiving sheet according to claim 17, wherein the layer provided on at least one side of the first layer of the composite film is a layer substantially not containing voids (voids). 19. The image receiving sheet according to claim 12, wherein said composite film is produced by simultaneous extrusion and subsequent biaxial stretching. 20. An image receiving sheet, characterized in that the support of the image receiving sheet is formed by laminating the composite film according to claim 12 on at least one surface of a core material. 21. The image receiving sheet according to claim 20, wherein the core is made of synthetic paper containing fiber paper or plastic film.