JPH068661A - Heat transfer sheet - Google Patents

Abstract

PURPOSE:To directly obtain a developed color image having high density, resolving power and continuous gradation like a photograph from an electric signal in a thermal transfer image receiving sheet constituted so as to be prevented from such a phenomenon that the thermal transfer layer of a thermal transfer sheet is bonded to the receiving layer of the thermal transfer image receiving sheet at the time of thermal transfer to be released and transferred. CONSTITUTION:A thermal transfer image receiving sheet 1 has a base material and the receiving layer 3 provided on the base material and receiving the dye transferred from a thermal transfer sheet at the time of heating and the receiving layer 3 contains a fluorine type surfactant and a release agent selected from amide wax or a 'Teflon(R)' powder. Or, the thermal transfer image receiving sheet has the base material 2, the receiving layer 3 provided on the base material and receiving the dye transferred from the thermal transfer sheet at the time of heating and the dye permeable release layer 4 provided on at least a part of the receiving layer 3 and the release layer 4 is constituted of a release agent selected from a fluorine type surfactant and solid wax.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat transfer sheet, and more particularly to a heat transfer sheet which is used in combination with a heat transfer sheet for performing heat printing according to image information by a thermal head or a laser.

[0002]

2. Description of the Related Art In order to obtain an image in accordance with image information by a thermal head or a laser, a thermosensitive coloring paper has been mainly used conventionally. In this heat-sensitive color-developing paper, a colorless or light-colored leuco dye and a developer provided on the base paper are brought into contact with each other by heating to obtain a color-developed image. As such a color developer, a phenolic compound, a zinc salicylate derivative, rosin and the like are generally used. However, the above-mentioned thermosensitive coloring paper has a fatal defect that the obtained colored image is erased when stored for a long period of time, and color printing is limited to two colors and has continuous gradation. It was not possible to obtain a color image.

On the other hand, in recent years, heat-sensitive transfer paper, in which a heat-melting wax layer having a pigment dispersed therein is provided on a base paper, has begun to be used. When the heat-sensitive transfer paper and the transfer-receiving paper are superposed and heat printing is performed from the back surface of the heat-sensitive transfer paper, the wax layer containing the pigment is transferred onto the transfer-receiving paper to obtain an image. According to such a printing method, a durable image can be obtained, and a multicolor image can be obtained by printing a plurality of times using a thermal transfer paper containing pigments of three primary colors. It is not possible to obtain a photographic image having continuous gradation.

By the way, in recent years, there have been increasing demands for directly obtaining images such as photographs from electric signals, and various attempts have been made. One of such attempts is a method of displaying an image on a CRT and photographing it with a silver salt film.
When the silver salt film is an instant film, there is a drawback that the running cost is high, and when the silver salt film is a 35 mm film, there is a drawback that it is not immediate because development processing is necessary after photographing. As another method, an impact ribbon method or an inkjet method has been proposed, but the former has a drawback that the image quality is poor, and the latter requires image processing, so it is difficult to easily obtain an image like a photograph. It has the drawback of being difficult.

In order to solve such a defect, a thermal transfer sheet provided with a sublimable disperse dye layer having a property of transferring by heating is used in combination with a thermal transfer sheet, and the thermal transfer sheet is controlled while controlling the sublimable disperse dye. A method has been proposed in which the image is transferred onto a sheet to obtain a photographic image with gradation. According to this method, an image having continuous gradation can be obtained from a television signal by a simple process, and a device used at that time is not complicated, and therefore, it is attracting attention. As one of the conventional techniques close to such a method, there is a dry transfer printing method of polyester fiber. In this dry transfer printing method, a dye such as a sublimable disperse dye is dispersed or dissolved in a synthetic resin solution. As a paint, apply this paint to thin paper etc. in a pattern and dry it to make a heat transfer sheet.This heat transfer sheet is superposed on polyester fiber which is a heat transfer sheet and heated closely to dye the disperse dye on the polyester fiber. Is a method of obtaining an image.

However, it is not possible to obtain a high density color image by superposing the thermal transfer sheet and the thermal transfer sheet made of polyester fiber as described above and printing them by heating with a thermal head or the like. The reason is that the surface smoothness of the polyester fiber cloth is not good, but it is considered to be mainly due to the following reason. That is, in the usual dry transfer printing method or wet transfer printing method, the transfer of the sublimable dye onto the polyester fiber cloth is carried out for a sufficient heating time, whereas heating by a thermal head or the like is usually performed. It is very short, as a result of which the dye does not migrate well onto the fabric. By the way, in the dry transfer printing method, transfer of the dye is achieved by heating at 200 ° C for about 1 minute, while heating by the thermal head is performed at 400 ° C for several msec.
It is as short as a degree.

In order to solve such problems and obtain an image having a sufficient density, a resin having a low glass transition point and a high affinity with a dye, such as a polyester resin (Vylon: Toyobo), is used for the receiving layer of the heat transfer sheet. ) Is being considered. In this case, the dye easily penetrates into the receiving layer even with the heating energy of the thermal head, and a high-density image may be obtained.

However, in the above-mentioned case, when the thermal transfer sheet and the thermal transfer sheet are superposed and heated and then the two sheets are peeled off, the thermal transfer layer of the transfer sheet itself becomes the receiving layer of the thermal transfer sheet. It becomes sticky and peels off and transfers, making it unusable at all. The cause is considered as follows.

(I) Polyethylene terephthalate (PET) is generally used as the base film of the thermal transfer sheet, but there are few transfer layer binders that firmly adhere to this base film.

(II) In order to obtain a high image density, it is necessary to use a resin having a low glass transition point and a low softening point as the receiving layer of the heat transferable sheet. Such a resin is generally added by a thermal head. It is softened by energy and shows tackiness.

As a result of further research based on these facts, the present inventors have found that the above-mentioned drawbacks can be solved all at once by using a heat transferable sheet having a specific constitution, and the present invention is realized. It came to completion.

[0012]

DISCLOSURE OF THE INVENTION The present invention is intended to solve the drawbacks of the prior art, that is, a thermal transfer sheet having a thermal transfer layer containing a heat transfer dye, and a thermal transfer having a specific structure. By using the sheet and the sheet in combination, the following objects are to be achieved.

(A) The thermal transfer layer of the thermal transfer sheet and the thermal transfer layer of the thermal transfer sheet are not fused by heat at the time of thermal transfer, and therefore the thermal transfer layer of the thermal transfer sheet adheres to the receiving layer of the thermal transfer sheet. To provide a thermal transfer sheet that does not transfer by peeling.

(B) To obtain a color image having high density, resolution, and continuous gradation directly from an electric signal like a photograph.

In order to achieve the above objects, the present invention provides a thermal transfer sheet provided with a receiving layer having the following properties, and the thermal transfer sheet is used in combination with the thermal transfer sheet. .

[0016]

[Means for Solving the Problems] That is, the heat transfer sheet of the first aspect of the present invention comprises a base material and a base material on which the dye transferred from the heat transfer sheet when heated is received. And a receptive layer containing a release agent selected from a fluorine-based or phosphoric acid ester-based surfactant, an amide wax or Teflon powder. .

The heat transferable sheet according to the second aspect of the present invention comprises a base material and a receiving layer provided on the base material for receiving the dye transferred from the heat transfer sheet when heated. , A dye-permeable release agent layer provided on at least a part of the receiving layer, and the release agent layer is selected from a fluorine-based or phosphoric ester-based surfactant or a solid wax. It is characterized by comprising a release agent.

The preferred embodiments of the present invention shown in the drawings will be described below. As shown in FIG. 1, the heat transferable sheet 1 of the first aspect of the present invention is configured by providing a receiving layer 3 on a base material 2. As shown in FIG. 2, the heat-transferable sheet 1 of the second aspect of the present invention has a receptive layer 3 provided on a substrate 2, and a release agent on at least a part of the receptive layer 3. A layer 4 is provided and configured.

The release agent layer 4 may be provided on the entire surface of the receiving layer 3, but may be provided only on a part of the receiving layer 3 as shown in FIG.

The base material 2 has a role of holding the receiving layer 3, and since heat is applied during thermal transfer, it is desirable that the base material 2 has a mechanical strength that does not hinder handling even in a heated state.

Specific examples of the base material 2 include condenser paper, glassine paper, sulfuric acid paper, highly sized paper, and flexible thin layer sheets such as plastic films. Of these, capacitor paper and polyethylene terephthalate film are often used, and when importance is attached to heat resistance, capacitor paper is mainly used, and when importance is attached to breakage resistance during handling by a mechanical device, polyethylene terephthalate film is used. Mainly used. The thickness of the substrate 2 is usually 3 to 50 μm, preferably about 5 to 15 μm.

As described above, the receiving layer 3 of the heat transferable sheet 1 has a function of receiving the dye transferred from the heat transfer sheet when heated, and specifically, the following ones are used. To be (A) Those having an ester bond Polyester resin, polyacrylic acid ester resin, polycarbonate resin, polyvinyl acetate resin, styrene acrylate resin, vinyl toluene acrylate resin, etc. (B) Those having a urethane bond, such as polyurethane resin. (C) Those having an amide bond Polyamide resin and the like. (D) Those having a urea bond, such as urea resin. (E) Others having highly polar bonds Polycaprolactone resin, styrene-maleic anhydride resin, polyvinyl chloride resin, polyacrylonitrile resin, etc.

In addition to the above synthetic resins, mixtures or copolymers of these may also be used.

Further, the receiving layer 3 can be formed of two kinds of resins having different properties. For example, -100 ~
The first region of the receiving layer is formed of a synthetic resin having a glass transition temperature of 20 ° C. and a polar group, and 40
The second region of the receiving layer can be formed by a synthetic resin having a glass transition temperature of ℃ or higher. Both the first region and the second region are exposed on the surface of the receiving layer, the first region occupies 15% or more of the surface, and the first regions exist in islands independent of each other. The longitudinal length of each of the shaped portions is preferably 0.5 to 200 μm.

The heat transfer sheet 1 according to the first aspect of the present invention
Includes a specific dye-permeable release agent in the receiving layer 3 made of the above resin.

Examples of such a release agent include solid waxes, fluorine-based or phosphoric acid ester-based surfactants,
Silicone oils and the like are used. These compounds are preliminarily added to the resin forming the receptive layer, and the resulting resin mixture solution is coated on a substrate and dried to obtain a receptive layer. Each of the release agents will be specifically described below. To do.

The solid wax is preferably dispersed as fine particles in the resin forming the receiving layer 3. Therefore, the solid wax is preferably treated with a ball mill, a sand mill or the like before being added to the resin. As the solid wax, polyethylene wax, amide wax, Teflon powder, etc. are used. This solid wax is contained in the resin in an amount of 5 to 50% by weight of the resin.
% By weight, preferably 10 to 20% by weight.
If the amount added is less than 5% by weight, a sufficient releasing effect may not be obtained and the thermal transfer layer may thermally adhere to the receiving layer. On the other hand, if the amount added exceeds 50% by weight, the dye transferred from the thermal transfer layer at the time of heating cannot be sufficiently received, so that the resulting image may not have sufficient resolution.

A fluorine-based or phosphoric acid ester-based surfactant is also added as a release agent in the resin forming the receiving layer. It is considered that the surfactant added to the resin partially appears on the surface of the receiving layer, and thus a releasing effect is obtained. As such a surfactant,
Specifically, as phosphoric acid ester compounds, Prysurf A208S, Prysurf A210G, Prysurf D
B-01 (above Daiichi Kogyo Seiyaku), Gaffac RS-41
0, Gafac RA-600, Gafac RE 610
(Above Toho Chemical Industry), and as the fluorine-based surfactant, Unidyne DS501, Unidyne DS502 (Daikin Industries), FC430, FC431 (Sumitomo 3M) and the like can be mentioned. The surfactant is added to the resin in an amount of 0.5 to 10% by weight based on the weight of the resin. If the amount added is less than 0.5% by weight, a sufficient releasing effect cannot be obtained. When the amount added is more than 10% by weight, the surface of the receiving layer becomes sticky or dust easily adheres to the surface, and when the transfer layer and the receiving layer come into contact with each other, the transfer layer does not need to be heated. Staining such as dye transfer to the receiving layer occurs.

Thermal transfer sheet 1 according to the second aspect of the present invention
As described above, the receptive layer 3 made of the resin is provided on the base material 2 and the release agent layer 4 is provided on at least a part of the receptive layer 3 as described above. The release agent layer 4 can be formed by dissolving or dispersing the above-mentioned release agent in a suitable solvent, applying the obtained solution or dispersion on the receiving layer 3, and then drying.

The thickness of the release agent layer is 0.01 to 5 μm.
m, preferably 0.05 to 2 μm. If the thickness of the release agent layer is less than 0.01 μm, a sufficient release effect cannot be obtained, while if it exceeds 5 μm, the permeability of the dye is disturbed, which is not preferable.

As described above, the release agent layer 4 may be provided on the entire surface of the receiving layer 3, but may be provided only on a part of the receiving layer 3. In general, it is difficult to print a description or the like on the release agent layer, but it is possible to print it on the receiving layer. Therefore, when it is necessary to print on the heat transferable sheet, it is preferable to provide the release agent layer only on a part of the receiving layer.

The thermal transfer sheet 1 as described above is used in combination with the thermal transfer sheet. As shown in FIG. 4, a typical thermal transfer sheet 5 is constructed by providing a thermal transfer layer 7 on one surface of a support 6, and the thermal transfer layer 7 is included in the thermal transfer layer 7 when it is heated. The coloring material is transferred onto the heat transfer sheet.

As such a coloring material, about 150-40
Examples thereof include disperse dyes having a relatively small molecular weight of about 0, oil dyes, certain basic dyes, and intermediates that can be converted into these dyes. Among these, thermal transfer temperature, thermal transfer efficiency, hue, It is selected and used in consideration of color rendering properties and weather resistance.

The above coloring material is provided on the support 6 by being dispersed in an appropriate synthetic resin binder forming the thermal transfer layer. As such a synthetic resin binder, it is usually preferable to select a binder that has high heat resistance and does not hinder the transfer of the coloring material that occurs when heated. For example, the following binders are used. (I) Cellulose-based resin Ethyl cellulose, hydroxyethyl cellulose, ethyl hydroxycellulose, hydroxypropyl cellulose, methyl cellulose, cellulose acetate, cellulose acetate butyrate, etc. (II) Vinyl resin Polyvinyl alcohol, polyvinyl acetate, polyvinyl butyral, polyvinyl pyrrolidone, polyester, polyacrylamide, etc.

Among the above synthetic resin binders, polyvinyl butyral resin or cellulose resin is preferable from the viewpoint of heat resistance and the like.

To provide the thermal transfer layer 7 on the support 6, a color material and a synthetic resin binder are kneaded together with a solvent or a diluent to prepare a thermal transfer layer coating composition, which is supported by an appropriate printing method or coating method. It may be provided on the body 6. In addition, you may add an arbitrary additive in the coating composition for thermal transfer layers as needed.

The basic structure of the thermal transfer sheet is as described above. However, when the surface of the support is directly heated by a contact type heating means such as a thermal head, as shown in FIG. A lubricant layer 8 containing a lubricant such as wax or a release agent on the side of the support 6 where the thermal transfer layer is not provided.
By providing the heating element, it is possible to prevent fusion between the heating means such as a thermal head and the support and improve the slip.

The thermal transfer sheet and the thermal transfer sheet prepared as described above are superposed facing each other so that the thermal transfer layer of the thermal transfer sheet and the receiving layer of the thermal transfer sheet are in contact with each other as shown in FIG. By applying thermal energy corresponding to image information to the interface between the and the receiving layer, the coloring material in the thermal transfer layer can be transferred to the receiving layer according to the thermal energy.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a thermal transfer sheet according to the present invention.

FIG. 2 is a cross-sectional view of a thermal transfer sheet according to the present invention.

FIG. 3 is a cross-sectional view of a thermal transfer sheet according to the present invention.

FIG. 4 is a sectional view of a thermal transfer sheet used in combination with a thermal transfer sheet.

FIG. 5 is a sectional view of a thermal transfer sheet used in combination with the thermal transfer sheet.

FIG. 6 is a cross-sectional view when a heat transfer sheet and a heat transfer sheet are used in combination.

[Explanation of symbols]

 1 Thermal Transfer Sheet 2 Base Material 3 Receptive Layer 4 Release Agent Layer 5 Thermal Transfer Sheet 6 Support 7 Thermal Transfer Layer 8 Sliding Layer

Claims (5)

[Claims] 1. A substrate, and a receiving layer provided on the substrate for receiving a dye transferred from a thermal transfer sheet when heated, wherein the receiving layer is a fluorine-based or phosphorus-based material. A thermally transferable sheet, which is used in combination with a thermal transfer sheet, containing a release agent selected from acid ester surfactants, amide wax or Teflon powder. 2. The thermal transfer sheet according to claim 1, wherein the release agent is present in the receiving layer in an amount of 0.5 to 30% by weight based on the weight of the receiving layer. 3. A base material, a receiving layer provided on the base material for receiving the dye transferred from the thermal transfer sheet when heated, and at least a part of the receiving layer. A dye-permeable release agent layer, wherein the release agent layer is made of a release agent selected from fluorine-based or phosphate ester-based surfactants or solid wax,
A thermal transfer sheet used in combination with a thermal transfer sheet. 4. The heat transferable sheet according to claim 3, wherein the release agent layer has a film thickness of 0.01 to 5 μm. 5. The heat transferable sheet according to claim 3, wherein the release agent layer is provided over the entire surface of the receiving layer.