JPH07164768A - Recording sheet - Google Patents

Abstract

PURPOSE:To easily record an image excellent in durability which has been difficult to embody hereto fore, by a method wherein a dye carrying layer containing sublimating dyes and a release layer are provided in order on one side of a base film. CONSTITUTION:This recording sheet 10 is formed of a dye carrying layer 2 and a release layer 3 in order on the surface of a base sheet 1. (The release layer 3 may be a dye carrying layer 2 containing a release agent.) Then a recording material 20 is formed of a dye receiving layer 5 and a release layer 6 in order on at least one side of the base sheet 4. Then at the time of recording, heat energy is imparted to the recorded material 20 in a patterned, as required, state under a heated state of the recorded material 20 by a heating roll 8 from the rear of the recording sheet 10 by a thermal head 7, through which sublimating dyes are transferred to a dye receiving layer 5 so as to perform transfer of an image.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a recording sheet used in a thermal recording method, and more specifically, it provides a recording sheet capable of easily recording an image having excellent fastness which has been difficult in the past.

[0002]

2. Description of the Related Art Conventionally, various thermal recording methods are known. Among them, a sublimable dye is used as a recording agent, and this is carried on a base material sheet such as paper to form a recording sheet. There is a sublimation transfer method in which a dyeable recording material, for example, a polyester sheet or a polyester fiber woven fabric is overlaid, and thermal energy is applied in a pattern from the back surface of the recording sheet to transfer the sublimable dye to the recording material. Has been done.

[0003]

In the sublimation transfer method described above, in the sublimation printing method in which the material to be recorded is, for example, a polyester woven cloth, the heat energy is applied for a relatively long time. As a result of itself being heated by the applied thermal energy, a relatively good dye transfer is achieved.

However, due to the progress of the recording method, a thermal head or the like is used at a high speed, for example, a recording material in which a dye receiving layer is provided on a polyester sheet or paper is used, and these recording materials are delicate. When forming characters, figures, or photographic images, it is required that heat energy is applied for an extremely short time of seconds or less. In such a short time, the sublimable dye and the recording material are not enough. Since it is not heated, an image with sufficient density cannot be formed.

Therefore, in order to cope with such high speed recording, a sublimable dye having excellent sublimation property has been developed. However, since the dye having excellent sublimation property generally has a small molecular weight,
After the transfer, it migrates with time in the recording material, or bleeds on the surface to disturb the image formed at the corners.
The problem of smearing or contaminating surrounding objects has arisen.

If a sublimable dye having a relatively large molecular weight is used to avoid such a problem, a satisfactory image cannot be formed as described above. Therefore, in the thermal recording method using a sublimable dye, by applying heat energy for an extremely short time as described above, a clear image with sufficient density is provided, and the formed image has excellent various fastnesses. Although there is a strong demand for the development of the recording sheet shown, it is the current situation.

As a result of earnest research to meet the strong demands of the industry as described above, the present inventor has conducted various researches on recording conditions in high speed recording using a conventional sublimable dye, and as a result, it has been confirmed that heat energy of an extremely short time can be obtained The present invention has been completed by finding a recording sheet on which a sublimable dye used is easily transferred to a recording material even when applied and a recorded image having a high density and various fastnesses is formed.

[0008]

That is, the present invention is a recording sheet comprising a substrate film and a dye-carrying layer containing a sublimable dye on one surface of the substrate film, and a release layer provided on the surface thereof. And a dye-carrying layer containing a sublimation dye and an anti-sticking inorganic powder or a releasing polymer on one surface of the base film.

[0009]

By forming a release layer on the surface of the dye-carrying layer of the recording sheet or by incorporating a releasing agent in the dye-carrying layer, even if the thermal energy applied from the thermal head is large, The carrier layer is less likely to be fused to the surface of the recording material, so that an image with high density and high durability is formed.

[0010]

The present invention will be described in more detail with reference to the following examples. First, for the understanding of the outline of the present invention, referring to the attached drawings, FIG. 1 schematically shows a preferred method of the present invention, in which 1 is a recording sheet.
Reference numeral 2 denotes a base material sheet constituting 10 and reference numeral 2 denotes a dye carrying layer formed on the surface of the base material sheet 1. In the present invention, the release layer 3 is formed on the surface of the dye carrying layer, or a release agent is included in the dye carrying layer. Reference numeral 4 denotes a substrate sheet constituting the recording material 20, 5 denotes a dye receiving layer provided on at least one surface thereof, 6 denotes a release layer provided on the surface of the dye receiving layer, and 7 denotes
Reference numeral 8 denotes a thermal head for applying heat energy, and 8 denotes a heating roll for heating the recording material as required. It should be noted that the accompanying drawings are illustrated for facilitating the description of the recording sheet of the present invention and a method of using the recording sheet, and do not limit the present invention in any way.

The basic idea of the method of the present invention is to form a release layer on the surface of the dye-carrying layer of the recording sheet as shown in the accompanying drawings showing a preferred example thereof, or to perform the releasing in the dye-carrying layer. It is to include an agent. With such a configuration, conventionally, in the application of instantaneous thermal energy by the thermal head, a dye-carrying layer made of a relatively high molecular weight dye that has not absorbed enough thermal energy and could not be sufficiently sublimated, However, even if a considerably high temperature is applied, the dye is not fused to the dye receiving layer of the recording material, and thus the dye can be easily sublimated and transferred. At the same time, when the thermal energy is momentarily applied by the thermal head, the dye receiving layer of the recording material cannot be heated, and thus the sublimated dye cannot be sufficiently received. Can be pre-heated to make it easily receptive.

Further, in a preferred embodiment of the present invention, a release layer is provided also on the dye receiving surface of the recording material,
Even if the recording material and / or the recording sheet are heated to a relatively high temperature, it is possible to prevent the contact surfaces of the recording material and / or the recording sheet from adhering or sticking or fusing. In the present invention, instead of the release layer, the dye-carrying layer may contain inorganic powder for preventing adhesion or a release agent.

In the present invention, with the above-mentioned constitution, if a dye having excellent sublimation property, which is used in a conventional thermal recording method using a sublimable dye, is used, recording at a higher speed than the conventional method can be carried out. Further, in the present invention, even when a sublimable dye having a relatively high molecular weight, which has a low sublimability and cannot be practically used in the conventional thermal recording method, is used, it is possible to impart high-speed heat energy for a short time. Recording is possible and therefore
In this case, since the dye constituting the obtained image has a relatively high molecular weight, there is no migration or bleeding of the dye in the dye receiving layer with the passage of time. The drawbacks of are solved.

Next, the recording sheet of the present invention, the material to be recorded, and the like will be described. The recording sheet of the present invention carries a sublimable dye on the surface of the base material sheet 1 as shown by 10 in FIG. The dye-carrying layer 2 and the releasing layer 3 are provided on the dye-carrying layer 2, or the mold-carrying layer 2 contains a releasing agent.

The base material sheet of such a recording sheet may be any one as long as it has a conventionally known degree of heat resistance and strength, for example, 0.5 to 50 μm.
m, preferably about 3 to 10 μm in thickness, various processed papers, polyester film, polystyrene film, polypropylene film, polysulfone film, polycarbonate film, polyvinyl alcohol film,
Cellophane and the like, and particularly preferable one is polyester film.

The dye carrying layer provided on the surface of the substrate sheet as described above is a layer in which a conventionally known sublimable (or disperse) dye is carried by an arbitrary binder resin. As the sublimable dye, conventionally known sublimable dyes, for example, as a representative example,
Miketon Polyester Yellow
-YL (manufactured by Mitsui Toatsu, CI Dispers Yel
low-42), Kayaset Yellow-G
(Manufactured by Nippon Kayaku, CI Dispers Yellow
77), PTY-52 (manufactured by Mitsubishi Kasei, CI Solv)
ent Yellow 14-1), Miketon
Polyester Red BSF (manufactured by Mitsui Toatsu,
C. I. Dispers Red111), Kayas
et RedB (manufactured by Nippon Kayaku, CI Dispers
Red B), PTR-54 (manufactured by Mitsubishi Kasei, C.I.
Disperse Red50), Miketon
Polyester Blue FBL (manufactured by Mitsui Toatsu,
C. I. Disperse Blue56), PTB-6
7 (manufactured by Mitsubishi Kasei, CI Disperse Blue 2
41), Kayase Blue 906 (manufactured by Nippon Kayaku, CI Solvent 112), and the like.

The above-exemplified sublimation dyes and other conventionally known sublimation dyes generally have a molecular weight of about 150 to 80.
In the conventional high-speed thermal recording method, some results were obtained with a molecular weight of about 150 to 400, but in the method of the present invention, for example, 400 or more,
Alternatively, even if it is 500 or more, a sufficiently satisfactory result can be obtained.

As the binder resin for supporting the sublimable dye as described above, any conventionally known binder resin can be used, and preferred examples are ethyl cellulose,
Hydroxyethylcellulose, ethylhydroxycellulose, hydroxypropylcellulose, methylcellulose, cellulose acetate, cellulose resins such as cellulose acetate butyrate, polyvinyl alcohol, polyvinyl acetate, polyvinyl butyral, polyvinylpyrrolidone, vinyl resins such as polyacrylamide, polyester, etc., It is preferable in terms of heat resistance, migration of dye, and the like.

The dye-carrying layer of the recording sheet of the present invention is basically formed of the above-mentioned components, but may also contain various additives similar to the conventionally known ones, if necessary. Such a dye-supporting layer is preferably a dye for sublimation described above in a suitable solvent, a binder resin and other optional components are added to dissolve or disperse each component to prepare a coating liquid or ink for forming a support layer, This is applied and dried on the above-mentioned substrate sheet to form.

The supporting layer thus formed has a thickness of 0.2 to
The thickness of the carrier layer is 5.0 μm, preferably 0.4 to 2.0 μm, and the sublimable dye in the carrier layer is 5 times the weight of the carrier layer.
Suitably it is present in an amount of ˜70% by weight, preferably 10 to 60% by weight. The recording sheet as described above is further provided with an anti-adhesion layer, that is, a release layer 3 on the surface of the dye carrying layer. The release layer 3 exhibits a considerable effect by simply adhering an anti-adhesive inorganic powder, and further, for example, from a resin having an excellent release property such as a silicone polymer, an acrylic polymer or a fluorinated polymer. 0.01-5μ
The effect of the present invention can be further improved by providing a release layer of m, preferably 0.05 to 2 μm. The inorganic powder or releasable polymer as described above can bring about a sufficient effect even when incorporated in the dye carrying layer. Further, a heat-resistant layer may be provided on the back surface of such a recording sheet in order to prevent adverse effects due to heat of the thermal head.

The recording material used in the present invention may be any one as long as its recording surface has dye receptivity for sublimable dyes, and paper, metal or glass having no dye receptivity. In the case of synthetic resin or the like, the dye receiving layer may be formed on at least one surface thereof.
Examples of the recording material that does not need to form a dye receiving layer include polyolefin resins such as polyethylene and polypropylene, halogenated polymers such as polyvinyl chloride and polyvinylidene chloride, polyvinyl alcohol, polyvinyl acetate, and polyacrylic ester. Vinyl polymers such as, polyethylene terephthalate, polyester resins such as polybutylene terephthalate, polystyrene resins, polyamide resins, copolymer resins of olefins such as ethylene and propylene and other vinyl monomers, ionomers,
Cellulose resins such as cellulose diacetate and cellulose triacetate, polycarbonate, polysulfone, polyimide and the like can be mentioned.

Among the recording materials made of these resins, there are some which cannot be used due to the too low dyeing property in the conventional high speed recording, but the present invention has made them sufficiently usable.
Particularly preferred is a polyethylene terephthalate sheet or film. In the present invention, even for non-dyeable recording materials such as paper, metal, glass, etc., the recording surface thereof is coated with a solution or dispersion of the dyeable resin as described above and dried, or Can be used as a recording material by laminating those resin films.

Further, even with the above-mentioned dyeing recording material, a dye-receiving layer may be formed on the surface of the recording material, as in the case of the above paper, from a resin having a further dyeing property. . The dye-receptive layer thus formed can be made of a single material,
Further, it may be formed from a plurality of materials, and it is a matter of course that various additives may be included within the range not impairing the object of the present invention.

Such a dye receiving layer may have any thickness, but is generally 5 to 50 .mu.m thick. Further, such a dye receiving layer is preferably a continuous coating, but it may be formed as a discontinuous coating by using a resin emulsion or resin dispersion. The above-mentioned recording material is basically as described above and can be used as it is, but when the recording material used for image formation is preheated to a relatively high temperature, the recording material or its dye receiving layer is used. It is preferable to include an inorganic powder for preventing stickiness. Particularly preferred is finely divided silica.

Here, silica refers to silicon dioxide or a substance containing silicon dioxide as a main component. The fine powder silica contained in the dye receiving layer has an average particle size of 10 to 100 μm.
m, a specific surface area of less than 250 m ² / g, more preferably an average particle size of 10 to 50 μm, a specific surface area of 20 to ²⁰⁰ m ^2.
/ G. If the average particle diameter of the fine powder silica is larger than this range, the dispersion stability of the fine powder silica in the dye receiving layer is lowered, and the smoothness of the surface of the dye receiving layer is significantly impaired, resulting in an unclear image. .

If the average particle size of the fine powder silica is smaller than this range, the effect of adding the fine powder silica to the dye receiving layer cannot be sufficiently exhibited. Specific examples of the fine powder silica satisfying the above conditions include Aerosil R972, Aerosil 130, Aerosil 200, and Aerosil O.
X50, Aerosil TT600, Aerosil MOX
80, Aerosil MOX170 (silica powder manufactured by Aerosil Co., Ltd.) and the like. The content of the fine powder silica is 5 to 20% by weight based on the weight of the dye receiving layer,
More preferably, it is in the range of 5 to 10% by weight.

Further, in place of or in combination with the above-mentioned inorganic powder such as silica, a resin having good releasability as described above may be added. Particularly preferable releasing polymer is a cured product of a silicone compound, for example, a cured product of an epoxy-modified silicone oil and an amino-modified silicone oil. Such a release agent is preferably contained in an amount of about 0.5 to 30% by weight based on the weight of the dye receiving layer. The recording material used in the present invention may have an anti-adhesive effect enhanced by adhering the above-mentioned inorganic powder to the surface of the dye-receiving layer, and also has excellent releasability as described above. A layer made of a releasing agent may be provided.

Such a release layer exerts a sufficient effect with a thickness of about 0.01 to 5 μm, and when the recording material is preheated, its preheating temperature is further raised to receive the dye on the recording sheet. The dye receptivity can be further improved while preventing adhesion with the layer. At least one of the recording sheet and the recording material is heated when the thermal recording is performed by the conventionally known method using the recording sheet and the recording material (each of which may be a conventionally known one). In this case, for example, as shown in FIG. 1, as a heating method, one or both of them are continuously passed through a heating roll immediately before recording, a method of using a heat ray such as infrared rays, and the entire recording atmosphere is heated. In any method such as the method of applying, the recording material and / or the recording sheet may be in an appropriately heated state, and the method is not limited.

The heating temperature of the recording material and / or recording sheet, preferably the recording material, may be a temperature equal to or lower than the temperature at which these recording material and / or recording sheet excessively soften and lose their shape. For example, at a temperature of 40 to 150 ° C, preferably 50 to 100 ° C, the intended purpose is sufficiently achieved. According to a detailed study by the present inventor, the recording material and / or
Alternatively, as the temperature of the recording sheet rises, the recording speed sharply rises. For example, as the temperature rises 10 ° C.,
The recording speed was doubled. Therefore, if the same thermal energy as in the conventional method is applied, the recording speed and the image density are remarkably improved, and if the same recording speed as in the conventional method, the density is sufficiently reduced with much less thermal energy. A high image can be formed.

As a means for applying heat energy when an image is formed using the recording sheet of the present invention, any conventionally known applying means can be used. For example, a thermal printer (for example, a thermal printer manufactured by Toshiba Corp., Thermal Printer TN-5
By controlling the recording time with a recording apparatus such as 400) and applying thermal energy of about 5 to 100 mJ / mm ² , the object of the present invention can be sufficiently achieved.

[0031]

According to the present invention as described above, the heat applied from the thermal head is formed by forming a release layer on the surface of the dye carrying layer of the recording sheet or by incorporating a release agent in the dye carrying layer. Even if the energy is large, the dye carrying layer is less likely to be fused to the surface of the recording material, so that an image having high density and high durability is formed.

[0032]

[Brief description of drawings]

FIG. 1 is a diagram schematically showing a method of using a recording sheet of the present invention.

[Explanation of symbols]

 1: Base material sheet 2: Dye carrying layer 3: Release layer 4: Base material sheet 5: Dye receiving layer 6: Release layer 7: Thermal head 8: Heating roll 10: Recording sheet 20: Recording material

Claims (5)

[Claims] 1. A recording sheet comprising a base material and a dye-carrying layer containing a sublimable dye on one surface of the base film, and a release layer provided on the surface. 2. The recording sheet according to claim 1, wherein the release layer is made of a resin having excellent release properties. 3. The recording sheet according to claim 2, wherein the resin having excellent releasing property is selected from a silicone polymer, an acrylic polymer or a fluorinated polymer. 4. A recording sheet comprising a substrate film and a dye-carrying layer containing a sublimable dye and an anti-sticking inorganic powder or a releasing polymer on one surface of the substrate film. 5. The releasing polymer is a silicone polymer,
The recording sheet according to claim 4, wherein the recording sheet is selected from acrylic polymers and fluorinated polymers.