JPH07137469A - Thermal transfer image receiving sheet - Google Patents

Abstract

PURPOSE:To obtain a thermal transfer image receiving sheet not generating curling after printing, that is, excellent in the feed aptitude within a printer and capable of forming an image having high glossiness by constituting a base material of a gloss layer, a foam layer and a core material from the side of a receiving layer and specifying the thickness and glossiness of the gloss layer. CONSTITUTION:A thermal transfer image receiving sheet is constituted of a colorant receiving layer 1 and a base material A and the base material A has a three-layered structure wherein foam layers 3, 3' are provided on both surfaces of a core material 2 and gloss layers 4, 4' each having thickness of 2mum or more and glossiness due to JIS Z-8741 of 85% or more are provided to the surfaces of the base material nearest to the colorant receiving layer. By this constitution, the thermal transfer image receiving sheet capable of obtaining a highly glossy image without damaging printing sensitivity and hard to generate curling after printing and excellent in the feed capacity within a printer can be obtained. Further, by using a sheet with surface roughness of 0.04-1.3 as a support, paper grain does not appear on the surface of the image receiving layer and an image of high quality free from missing dots is formed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermal transfer image-receiving sheet having a receptive layer for receiving a color material transferred from a sublimation thermal transfer sheet, and more specifically, it can be widely used in various color printer fields such as video printers. The present invention relates to a thermal transfer image-receiving sheet having excellent glossiness.

[0002]

2. Description of the Related Art In recent years, image forming systems represented by photographing technology and computer graphics have made remarkable progress. Along with this, the need for color hard copies of images has been increasing. Among various hard copy systems, a thermal transfer image-receiving sheet is placed on a thermal transfer sheet using a sublimable dye as a recording material, and a dye is transferred to the thermal transfer image-receiving sheet by heating with a thermal head according to a recording signal to form a recorded image. The method of obtaining the image is extremely focused because the image formed is excellent in transparency, gradation reproducibility of intermediate colors and color reproducibility, and an image comparable to a silver halide photograph can be obtained.

The thermal transfer image-receiving sheet used in such a sublimation transfer system is free from density unevenness, missing dots, etc., and can provide a high-density and high-definition image. High performance is required such that curling does not occur, that is, excellent paper feeding / discharging performance and conveyance suitability in the printer. Further, these thermal transfer image-receiving sheets are required to have high gloss like silver salt photographic printing paper. For example, JP-A-3-216386
In the publication, a surface of a porous film substrate made of a biaxially stretched film of a thermoplastic resin containing an inorganic fine powder as a support of an image-receiving sheet is coated with a thermoplastic resin film having a central average roughness of 0.5 μm or less. A support having a structure in which the surface layer is adhered is used, and the thickness of this surface layer is 0.3 to 1.
Since the thickness is 5 μm, the image receiving sheet has no gloss.

Further, in Japanese Patent Laid-Open No. 5-169865,
At least one layer containing a thermoplastic resin and an inorganic pigment as main components and having a void structure, the intermediate layer consisting of a stretched non-porous film having a thickness of 0.5 to 5 μm containing a thermoplastic resin as a main component; There is described a dye thermal transfer image-receiving sheet which is provided on a sheet-shaped support made of a stretched porous film and further provided with a receiving layer as an intermediate layer, but the glossiness of the image-receiving sheet is not described at all.

[0005]

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention As means for imparting high glossiness to a thermal transfer image-receiving sheet such as silver salt photographic printing paper and imparting the ability to obtain a high density and high definition image, Various methods have been used. One example is to use a single-layer or three-layer laminated base material made of polyethylene terephthalate film (or sheet) as the base material of the thermal transfer image-receiving sheet. However, this method has a problem that the curl after printing is adversely affected although the gloss is excellent. In addition, the method of using a three-layer laminated base material that uses a foam base material sheet on both sides of a core material, which is usually used, has excellent curling performance after printing, but has a problem of poor glossiness of an image. Therefore, an object of the present invention is to provide a thermal transfer image-receiving sheet which does not cause curl after printing, that is, has excellent transportability in a printer and can form a high gloss image.

[0006]

The above object can be achieved by the present invention described below. That is, the present invention is a thermal transfer image-receiving sheet comprising at least a color material receiving layer and a base material, wherein the base material has at least a gloss layer, a foam layer and a core material from the receiving layer side, and the thickness of the gloss layer is Of 2 μm or more and the glossiness of the glossy layer is 85% or more as measured by Method 4 of JIS Z-8741, and a thermal transfer image-receiving sheet comprising at least a colorant-receiving layer and a substrate. In the thermal transfer image-receiving sheet according to the present invention, the substrate comprises a core material, a foam layer and a gloss layer, and the core material has a surface roughness (Ra) of 0.
The thermal transfer image-receiving sheet is in the range of 04 to 1.3.

[0007]

By providing the thermal transfer image-receiving sheet as described above, a high-gloss image can be obtained without impairing the printing sensitivity, and curling does not easily occur after printing, so that the thermal transfer image-receiving sheet excellent in conveyance performance in the printer is provided. You can do it. Further, by using a sheet or film having a specific surface roughness (Ra) as the core material constituting the base material, in addition to the above-mentioned effect, no paper grain appears on the surface of the receiving layer and there is no dot omission. A thermal transfer image receiving sheet on which a high quality image is formed can be provided.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in more detail with reference to the preferred embodiments. A preferred example of the thermal transfer image-receiving sheet of the present invention is composed of a color material receiving layer 1 and a base material A, as shown in the cross section of FIG.
The core material 2 has a three-layer structure having the foam layers 3 and 3'on both surfaces, and has a thickness of 2.0 on the surface of the base material closest to the color material receiving layer 1.
This is a structure in which the gloss layers 4 and 4 ′ having a specific glossiness of μm or more are provided. An example of a thermal transfer image-receiving sheet according to another preferred embodiment of the present invention is composed of a color material receiving layer 1 and a base material A, as shown in the cross section of FIG.
The base material A has a structure in which the foam layer 3 and the gloss layer 4 are provided on one surface of the core material 2 having a surface roughness (Ra) of 0.04 to 1.3.

In the above structure, first, the foam layers 3 and 3 '.
As the foaming material, foamed polyester, foamed polyolefin, and other known foamed sheets may be used, but foamed olefin sheets, particularly synthetic polypropylene sheets and foamed polypropylene sheets are preferable. Microscopically, the foam layers 3 and 3 ′ are foam layers /
In the case of the three-layer structure of non-foamed layer / foamed layer, this is regarded as one layer in the present invention. This foam layer can be obtained by uniaxially or biaxially stretching a sheet-shaped mixture of a resin such as polyolefin such as polyester and polypropylene and inorganic fine particles such as titanium oxide and barium sulfate. By this stretching treatment, a foamed structure can be obtained, and at the same time, uneven thickness of the sheet can be eliminated. Further, at the time of forming the foam layer, the following gloss layer-forming resin may be coextruded, and the foam layer and the gloss layer may be stretched at the same time.

Gloss layers 4 and 4'are provided in the portions of the foam layers 3 and 3'that are closest to the color material receiving layer 1. This glossy layer 4,
The material of 4'is not particularly limited, but as the resin for the gloss layer, a known resin having an effect of imparting gloss such as polyolefin resin such as polypropylene, polyester, polyurethane, acrylic resin or the like can be used. In order to give gloss, the thickness of the gloss layers 4 and 4'is 2.0.
The thickness is not less than μm, preferably about 2.0 to 20 μm. If the thickness is less than 2.0 μm, the desired glossiness cannot be imparted by using any material. Also, the gloss layer is 2
If it exceeds 0 μm, the cushioning property of the foam layer is impaired, which may adversely affect the printing sensitivity. Further, the gloss layers 4 and 4'have a function of covering the unevenness on the surface of the foam layers 3 and 3'under which the light is scattered and imparting the above gloss. As the method for forming the gloss layer, the resin for forming the gloss layer may be coextruded at the time of forming the foam layer as described above, and the foam layer and the gloss layer may be stretched at the same time, or the resin described above may be applied. You may work. Further, when a similar gloss layer is provided on the core material side of the foam layer, the adhesive strength between the foam layer and the core material is improved.

The core material 2 as the center of the base material A is not particularly limited as long as it is a material having a certain degree of rigidity such as plastic film and paper. As the plastic film material, polyolefin, polyester, polyacrylic, polyvinyl chloride, and other known plastic films can be used. As the paper, use known paper such as plain paper, high-quality paper, double-sided or single-sided coated paper, double-sided or single-sided art paper, double-sided or single-sided cast coated paper, glassine paper, synthetic paper, tracing paper, condenser paper. Can be done. When these core materials are pasted together, the thermal loss of the film during printing with the thermal head prevents the occurrence of a step between the printed part and the non-printed part, and
Curls can also be suppressed.

It is preferable to use a heat-resistant plastic film, especially a biaxially stretched polyethylene terephthalate film, as the core material 2. However, when a transparent film is used, the hiding property of the entire heat transfer image receiving sheet is inferior and the heat transfer image receiving sheet is used. When is superimposed on other printed matter, characters and the like on the printed matter may be seen through. In order to provide concealing properties and improve whiteness, titanium oxide, calcium carbonate, barium carbonate, barium sulfate, titanium oxide, An inorganic pigment such as talc or an organic pigment may be contained. The content is preferably about 10 to 50% by weight with respect to the resin forming the plastic film.

The surface irregularities of the core material 2 also greatly contribute to the irregularities of the entire thermal transfer image receiving sheet. When the Ra value of the surface roughness of the core material 2 exceeds 1.3, fine unevenness appears even on the surface of the color material receiving layer, so that white spots are likely to occur in the obtained image and high density printing is obtained. It may be difficult to get caught.
On the other hand, if Ra is less than 0.04, it is too smooth, and therefore double feeding may occur when the image receiving paper is stored in the paper feed tray in the printer. When only paper is used as the core material, the high-grade feeling of the printed matter is diminished due to the surface waviness of several μm to several cm due to the unevenness of papermaking during papermaking. On the other hand, in the case of a plastic film, since no waviness occurs, a smooth and high-quality printed matter can be obtained. The Ra value in this surface roughness is SURF-COM 570A-3 manufactured by Tokyo Seimitsu.
It is a value measured by DF or the like.

As a method for obtaining the base material by laminating the foam layers 3, 3'and the core material 2 described above, known laminating methods such as ordinary dry lamination, wet lamination and extrusion lamination can be used. Further, the total thickness of the base material A is preferably in the range of 100 μm to 250 μm in consideration of the printer conveyance performance due to the rigidity and the printing pressure of the thermal head and the platen roll. Therefore, the thickness of each layer constituting the base material is also determined by the combination within this range.

Even when the receiving layer is provided on one side, curling at the time of printing can be prevented, but from the aspect of preventing environmental curling during storage, the other side of the core material 2 has a heat insulating effect. It is advisable to laminate a foamed resin film having excellent heat resistance. As the foamed film, a combination of a foamed layer and a glossy layer used on the receiving layer side can be used as it is, in addition to a normal foamed film.

Next, regarding the color material receiving layer 1, an intermediate layer (not shown) may be provided between the base material and the color material receiving layer 1. Resins forming the intermediate layer include polyurethane resins, polyolefin resins such as polyethylene resins, polybutadiene resins, polyacrylic acid ester resins, epoxy resins, polyamide resins, rosin-modified phenol resins, terpene phenol resins, ethylene / vinyl acetate copolymers. Resins such as resins and polyvinyl chloride resins may be used alone or in combination of two or more. In addition, these resins include
Depending on the purpose such as hiding and whiteness, various inorganic pigments,
Organic pigments and other fine particles, and additives such as fluorescent agents can be added. The thickness of this layer is preferably about 1 to 10 μm.

The intermediate layer is kneaded with a solvent, a diluent or the like, together with other additives as required, into a paint or an ink, and the known coating method such as gravure coating method or knife coating method is used. It can be formed by applying a coating film by any coating means such as a slide coating method, a cast coating method, a reverse roll coating method, and then drying it.

The material for forming the colorant receiving layer 1 is, for example, a polyolefin resin such as polypropylene, a polyvinyl chloride / vinyl acetate copolymer, an ethylene / vinyl acetate copolymer, a halogenated polymer such as polyvinylidene chloride. Polyester resins such as polyvinyl acetate and polyacrylic ester, polystyrene resins, polyamide resins, copolymer resins of olefins such as ethylene and propyne with other vinyl monomers, cellulosic resins such as ionomers and cellulose diacetate. Polycarbonate and the like are mentioned, and particularly preferable ones are polyester resins and vinyl chloride / vinyl acetate copolymers.

At the time of image formation, a release agent is mixed with the sublimation heat transfer sheet having a dye layer for the purpose of preventing fusion of the color material receiving layer of the thermal transfer image receiving sheet or deterioration of printing sensitivity. You can do it. Preferred releasing agents to be mixed and used include silicone oils, phosphate ester type surfactants, fluorine type surfactants and the like. Among them, silicone oils are preferable. As the silicone oil, modified silicone oil such as epoxy modified, vinyl modified, alkyl modified, amino modified, carboxyl modified, alcohol modified, fluorine modified, alkylaralkyl polyether modified, epoxy / polyether modified, polyether modified, etc. is desirable.

As the release agent, one type or two or more types are used. The amount of the release agent added is preferably 0.5 to 30 parts by weight with respect to 100 parts by weight of the colorant receiving layer forming resin. If the addition amount range is not satisfied, problems such as fusion between the sublimation heat transfer film and the color material receiving layer of the heat transfer image-receiving sheet or reduction in printing sensitivity may occur. By adding such a release agent to the color material receiving layer, the release agent bleeds out on the surface of the color material receiving layer after transfer to form a release layer. Further, these release agents may be separately coated on the color material receiving layer without being added to the resin for forming the color material receiving layer.

The colorant receiving layer is prepared by dissolving the resin as described above to which the necessary additives such as a releasing agent are added on the surface of the gloss layer or the intermediate layer in a suitable organic solvent, or an organic solvent. It is formed by applying and drying a dispersion dispersed in water or water by the same forming means as the above-mentioned intermediate layer. In the formation of the color material receiving layer, a fluorescent whitening agent or the like can be added for the purpose of improving the whiteness of the dye receiving layer and further improving the sharpness of the transferred image. The colorant receiving layer formed as described above may have any thickness, but generally 1 to 50.
The thickness is μm.

Although such a color material receiving layer is preferably a continuous coating, it may be formed as a discontinuous coating using a resin emulsion or a water-soluble resin or a resin dispersion. Further, an antistatic material may be coated on the color material receiving layer in order to stabilize the transportability of the printer. Further, when the color material receiving layer is provided only on one surface of the thermal transfer image receiving sheet, an appropriate slip layer 5 is formed on the surface of the base material opposite to the receiving layer in order to prevent double feeding during paper feeding in the printer. Can be provided. As the slip layer, butyral resin, polyacrylic acid ester, polymethacrylic acid ester, polyvinylidene chloride, polyester, polyurethane, polycarbonate, polyvinyl acetate alone or a blend of known resins, various fine particles and silicone etc. It is possible to use a material to which a lubricant is added.

[0023]

EXAMPLES Next, the present invention will be described more specifically with reference to Examples and Comparative Examples. In addition, "parts" or "%" in the text are based on weight. Example 1 Art paper as core material (made by Kanzaki Paper Manufacturing, satin Kinfuji, basis weight 8
4.7 g / m ² ) and expanded polypropylene film (Toyobo, P-6255, thickness 80 μm) on both sides
m, having a gloss level of 100.1% on both sides and a gloss layer of 5 μm in thickness) were bonded together with an adhesive to obtain a substrate. On the other hand, a coating liquid for a colorant receiving layer having the following composition was prepared, and the coating liquid was applied to one glossy layer surface of the above substrate at a solid coating amount of 3.0 g /
m ² is applied and dried to form a colorant receiving layer,
A thermal transfer image-receiving sheet of the present invention was obtained.

Composition of coating liquid : Vinyl chloride / vinyl acetate copolymer (1000A manufactured by Denki Kagaku Kogyo) 36 parts Vinyl chloride / styrene / acrylic copolymer (# 400 manufactured by Denki Kagaku Kogyo) 8 parts Polyester (Vylon manufactured by Toyobo) 600) 56 parts Toluene 200 parts Methyl ethyl ketone 200 parts Vinyl modified silicone (Shin-Etsu Chemical Co., Ltd.) 10 parts Platinum catalyst (Shin-Etsu Chemical Co., Ltd.) 1 part

Example 2 A foamed polypropylene film having a thickness of 80 μm, a gloss layer thickness of 3.5 μm and a glossiness of the gloss layer of 96.4% was used in place of the foamed polypropylene film in Example 1, and the other examples were used. A thermal transfer image-receiving sheet of the present invention was obtained in the same manner as in 1. Example 3 Instead of the foamed polypropylene film in Example 1, a foamed polypropylene film having a thickness of 80 μm, a gloss layer thickness of 25 μm, and a glossiness of the gloss layer of 101.3% was used, and otherwise the same as in Example 1. A thermal transfer image-receiving sheet of the present invention was obtained.

Example 4 Instead of the foamed polypropylene film in Example 1, a foamed polypropylene film having a thickness of 75 μm, a gloss layer thickness of 12 μm and a gloss layer gloss of 100.3% was used. Similarly, a thermal transfer image-receiving sheet of the present invention was obtained. Example 5 A white polyester film (manufactured by Diamond Foil, W-100, thickness 65 μm, Ra = 0.04) was used as a core material, and a foamed polypropylene film (manufactured by Toyobo, P-6255, thickness) was used on one surface thereof. A thermal transfer image-receiving sheet of the present invention was obtained in the same manner as in Example 1 except that a substrate having a thickness of 80 μm, glossiness of 100.1% on both sides and a thickness of 5 μm) was attached by an adhesive. Example 6 A white polyester film (made of diamond foil, W-400, thickness 75 μm, Ra = as a core material in Example 5
0.16) was used and otherwise in the same manner as in Example 5 to obtain a thermal transfer image-receiving sheet of the present invention.

Example 7 As the core material in Example 5, a polyester film having Ra = 1.30 (the white polyester film used in Example 6 was roughened) was used. Similarly, a thermal transfer image-receiving sheet of the present invention was obtained. Example 8 A thermal transfer image-receiving sheet of the present invention was obtained in the same manner as in Example 5, except that the expanded polypropylene film was formed on both sides of the core material in Example 5. Comparative Example 1 Instead of the foamed polypropylene film in Example 1, a foamed polypropylene film having a thickness of 60 μm, a gloss layer thickness of 1.5 μm, and a glossiness of the gloss layer of 84.7% was used. Others were the same as in Example 1. A thermal transfer image receiving sheet of Comparative Example was obtained.

Comparative Example 2 A thermal transfer image-receiving sheet of Comparative Example was obtained in the same manner as in Example 5, except that a roughened PET film (Ra = 1.40) was used as the core material in Example 5. . Here, the surface roughening treatment was performed by heating a metal roll to 150 ° C. and passing a film between the rolls at a linear pressure of 7 kgf / m. Comparative Example 3 A transparent polyester film (F-60 manufactured by Toray, thickness 75 μm, Ra = 0.02) as a core material in Example 5.
A thermal transfer image-receiving sheet of a comparative example was obtained in the same manner as in Example 5 except that was used.

On the other hand, a dye layer-forming ink composition having the following composition was prepared, and a 6 μm-thick polyethylene terephthalate film having a back surface subjected to heat treatment had a dry coating amount of 1.0.
A thermal transfer sheet was obtained by coating and drying with a wire bar so as to obtain g / m ² . Ink composition; C.I. I. Disperse Blue 24 1.0 part Polyvinyl butyral resin 10.0 parts Methyl ethyl ketone / toluene (weight ratio 1/1) 90.0 parts

The above-mentioned thermal transfer sheet and the above-mentioned thermal transfer image-receiving sheet of the present invention and the comparative example are superposed with their dye layers and coloring material receiving surfaces facing each other, and a head applied voltage of 12.0 V is applied from the back surface of the thermal transfer sheet. , Pulse width 16 msec. Recording was performed with a thermal head under the condition of a dot density of 6 dots / line, and the results shown in Table 1 below were obtained. In addition, the evaluation method of each performance shown in Table 1 was performed as follows. Gloss : Measured by JIS Z-8741 Method 4 Sensitivity : ◯: Excellent Δ: Acceptable ×: Not acceptable

Curl : ⊚: None at all ○: When placed on a horizontal surface, the height of both ends of the image receiving sheet after printing of size A5 is less than 5 mm, respectively: When placed on a horizontal surface, after printing of size A5 The height of both ends of the image receiving sheet is 5 to 10 mm, respectively: ×: Not possible (conveyance error occurred) Printing quality : ◎: High- quality feeling ○: No missing dots Δ: Some missing dots ×: Many missing dots is there

[0030]

[Table 1] Performance evaluation

[0032]

[Effects] According to the present invention as described above, a high-quality image having high image glossiness can be obtained without impairing the sensitivity, and curl after printing is less likely to occur, so that a thermal transfer image-receiving sheet excellent in printer conveyance performance is provided. You can

[0033]

[Brief description of drawings]

FIG. 1 is a diagram schematically illustrating a cross section of a thermal transfer image receiving sheet of the present invention.

FIG. 2 is a diagram schematically illustrating a cross section of a thermal transfer image receiving sheet according to another example of the present invention.

[Explanation of symbols]

 A: Substrate 1: Color material receiving layer 2: Core material 3, 3 ': Foaming layer 4, 4': Gloss layer 5: Slip layer

Claims (4)

[Claims] 1. A thermal transfer image-receiving sheet comprising at least a color material receiving layer and a base material, wherein the base material has at least a gloss layer, a foam layer and a core material from the receiving layer side, and the thickness of the gloss layer. Is 2 μm or more and the gloss level of the gloss layer is JIS
A thermal transfer image-receiving sheet characterized by having a content of 85% or more as measured by Method 4 of Z-8741. 2. The base material is at least centered on the foam layer,
The thermal transfer image-receiving sheet according to claim 1, wherein a stretched film having a gloss layer having a thickness of 2.0 μm or more provided on both sides thereof and a core material are bonded together. 3. A thermal transfer image-receiving sheet comprising at least a color material receiving layer and a base material, wherein the base material comprises a core material, a foam layer and a gloss layer, and the core material has a surface roughness (Ra) of 0. 0
A thermal transfer image-receiving sheet characterized by being in the range of 4 to 1.3. 4. The glossiness of the glossy layer is JIS Z-8741.
It is 85% or more in the measurement by the method 4 of 3.
The thermal transfer image-receiving sheet as described in 1.