JP2907429B2 - Base sheet for thermal transfer image receiving sheet - Google Patents

Description

Description: FIELD OF THE INVENTION The present invention relates to a base sheet for a thermal transfer image receiving sheet. More specifically, the present invention provides a printer using large thermal energy, such as a dye heating sublimation type printer, without curling by heat.
The present invention relates to a base sheet useful for a thermal transfer image receiving sheet capable of sharply transferring a full-color print image by a thermal transfer ink such as a sublimated dye and capable of printing a high-resolution halftone image with high fidelity.

[Conventional technology]

In recent years, color printers capable of printing clear color images with a relatively compact device, particularly color printers of a thermal transfer system such as a dye sublimation type, have attracted attention.

Among these color printers, a dye sublimation transfer type printer is an image receiving sheet containing a sublimation dye-dyeing polyester resin of an image receiving sheet in an ink sheet composed of a substrate such as a film or thin paper and a sublimation ink layer. The surface of the layers are superposed, and the sublimation ink is transferred to the image receiving sheet by a required portion and a required density to form an image by the heat supplied from the thermal head according to the electric signal. However, in such a sublimation type thermal transfer system, the uniformity of the base material of the image receiving sheet affects the uniformity and sharpness of the obtained transfer image. The same high-level printing is not possible with a receiving sheet.

Good printing on image receiving sheet for thermal transfer printer,
In order to obtain a print, it is known to form a base sheet by laminating and laminating a biaxially stretched multi-layer film containing a polyolefin containing an inorganic pigment as a main component on a support. In the image receiving sheet for a sublimation transfer printer, an image receiving layer containing a polyester resin is formed on the base sheet. Such a base layer sheet has a uniform thickness,
Due to its advantages such as flexibility and lower thermal conductivity than paper made of cellulose fiber, there is an advantage that a uniform and high-density transfer image can be obtained.

However, when a biaxially stretched multilayer structure film containing a polyolefin as a main component is used as a base layer sheet of an image receiving sheet for a thermal transfer printer, the resulting image receiving sheet is subjected to a thermal transfer operation to form a base layer sheet. The axially stretched multi-layer polyolefin film has drawbacks such as heat shrinkage, resulting in curling or wrinkling of the film, which causes trouble in running the sheet and significantly lowers the commercial value of the print. In particular, in the sublimation transfer system, since the amount of heat applied to the image receiving sheet is large, this problem has occurred remarkably.

On the other hand, it is conceivable to use, as a support of the base layer sheet, a sheet base material composed of a biaxially stretched multi-layer film mainly composed of polyolefin containing an inorganic pigment.
Such sheets are known as synthetic paper, and can be printed,
It is used for writing and printers.
In order to solve the drawbacks of this synthetic paper, such as weakness and heat shrinkage, it is also known that this sheet is laminated with a film of polyester or the like, a multilayer film, or a synthetic paper / paper / synthetic paper. Have been.

It is also known that the synthetic paper can be used as an image receiving sheet for thermal transfer such as a sublimation transfer system to improve the quality of a transferred image. However, there is a problem that curling is generated due to heat shrinkage during processing or printing at the time of poor heat resistance.

In order to prevent the curl due to the heat shrinkage, a multi-layer laminated image receiving sheet in which a core material such as paper, polyester (PET), film or the like is laminated between synthetic papers is also known.

However, in a thermal transfer type printer, heat is applied to only one surface of an image receiving sheet from a thermal head or the like, and particularly in a sublimation transfer type, a receiving layer for dyeing a sublimation dye image has a heat shrinkable property. In the case where the laminated body is formed of a polyester resin having the above-mentioned property, the occurrence of thermal curl cannot be sufficiently prevented even with the above-described three-layer laminated body.

[Problems to be solved by the invention]

The present invention provides a base layer sheet useful for a thermal transfer image receiving sheet which has good printing suitability for other thermal transfer printers, including a sublimation method, and which has solved the above-mentioned drawbacks caused when the multilayer structure film is used. With the goal.

[Means for solving the problem]

According to the present invention, there is provided a sheet-like support having a thickness of from 20 to 300 μm, and a biaxially stretched sheet containing a polyolefin resin as a main component on its surface (the surface on which an image receiving layer is formed) and the back surface, respectively. The resin film for forming a front surface side resin coating layer comprising a front side resin coating layer and a back side resin coating layer formed by laminating and bonding the multilayered resin film thus formed, and a thickness X ₁ (μm) of the resin film for forming a front side resin coating layer, The thickness X ₃ (μm) of the resin film for forming the backside resin coating layer satisfies the following relationship: 10 ≦ X ₃ −X ₁ ≦ 40 Formula Achieved by sheet.

The sheet-like support used in the method of the present invention has a thickness of 20 to 300 μm.
m. If the thickness is less than 20 μm, the stiffness of the sheet-like support is weak, and the curl generated during image thermal transfer cannot be sufficiently prevented.If the thickness exceeds 300 μm, for example, when the sheet-like support is mounted in a color printer, There is a disadvantage that the body becomes too thick and hinders downsizing of the printer.

The support used in the present invention has a small heat shrinkage and preferably has a heat shrinkage at 100 ° C. of 0.1% or less according to a method of measuring a heat shrinkage by a heat stretching test of JIS K-6734. Such supports include high quality paper, medium quality paper,
Japanese paper, tissue paper, coated paper (lightly coated paper, lightweight coated paper,
And non- or low heat-shrinkable synthetic resin films made of polyester, polyolefin, nylon, and the like. Here, coated paper is
Pigments such as kaolin, clay, calcium carbonate, aluminum hydroxide, and plastic pigment, water-soluble adhesives such as starch, and / or synthetic polymer emulsion adhesives such as styrene and butadiene are mainly used on high-quality or medium-quality paper. It is a coating and coating of a coating layer as a component. The coated paper preferably has a rice tsubo of 50 to 200 g / m ² and a coating amount of about 5 to ²⁰ g / m ² .

The resin film used for forming the front and back side resin coating layers of the present invention is, for example, a biaxially stretched synthetic paper having a multilayer structure of a polyolefin containing a conventionally well-known inorganic pigment (for example, titanium dioxide). Synthetic paper with a three-layer structure in which a paper-like layer made of a uniaxial or biaxially stretched film is bound to the front and back surfaces of the base material layer, and four or more layers in which layers other than the paper-like layer and the base material layer exist. Synthetic paper may be used. Further, a film mainly composed of other thermoplastic resin such as polyolefin and polypropylene may be used.

In the base sheet of the present invention, the thickness of the support is set to X ₂ (μ
m), the thickness of the resin film for forming the surface-side resin coating layer is X ₁
(Μm), when the thickness of the resin film for forming the backside resin coating layer is X ₃ (μm), it is necessary that the relationship of the following formula be satisfied, and 10 ≦ X ₃ −X ₁ ≦ 40 − Formula It is preferable that the following relationship be satisfied: 100 ≦ X ₁ + X ₂ + X ₃ ≦ 370 −Formula X ₁ ≧ 30 −Formula 20 ≦ X ₂ ≦ 300 In this manner, when an image is printed, it is possible to prevent the occurrence of film curl and wrinkles due to the heat of the thermal head, and to prevent running trouble due to the curl and wrinkles.

As shown in FIG. 1, a base layer sheet 4 for a thermal transfer image receiving sheet of the present invention comprises a support 1 on which a film for forming a front side resin coating layer 2 and a film for forming a back side resin coating layer 3 are formed. It is formed by laminating.

This lamination is preferably performed using an adhesive, but may be performed by heat bonding. As the adhesive, a polyether-based, polyester-based adhesive, or the like can be used, and it is preferable to be selected from adhesives for dry lamination having high heat resistance.

As shown in FIG. 2, an image receiving layer 5 is formed on the surface side resin coating layer 2 of the base layer sheet 4 of the present invention to obtain a thermal transfer image receiving sheet 6.

(Operation)

In the present invention, since the thickness of the resin film for forming the backside resin coating layer is larger than the thickness of the resin film for forming the front side resin coating layer, the shrinkage force due to the heating of the thick film is smaller than the shrinkage force due to the heating of the film. When a thermal transfer image is received, uneven heating due to heat transfer from one side and this difference in shrinkage force cancel each other out, and the curl and wrinkles balance with respect to heating as a whole of the base sheet, which is a laminate. Is prevented from occurring.

Hereinafter, the present invention will be described in more detail with reference to Examples.

Example 1 Yupo FPG80 (80 μm thick), which is a multi-layered film biaxially stretched with a polyolefin containing an inorganic pigment as a main component,
m, Oji oil-based synthetic paper) as the front side resin coating layer, and YUPO FPG110 (thickness 110 μm, Oji oil-based synthetic paper) as the back side resin coating layer, high-quality paper (OK foam paper Oji Paper)
These three layers are laminated by dry lamination with a polyester-based adhesive (S-3911 Toa Gosei Chemical Industry Co., Ltd.) as a support, using a rice tsubo 64 g / m ² , a thickness of 56 μm, a heat shrinkage rate of 0.1%) as a support. Thus, a base layer sheet for a thermal transfer image receiving sheet was obtained.

Example 2 An OPP film (thickness: 50 μm, Toyobo) was used as a front side resin coating layer, a YUPO FPG60 film (thickness: 60 μm, Oji Yuka synthetic paper) was used as a back side resin coating layer, and coated paper (thickness: 50 μm) was used.
m, coating weight 7 g / m ² , basis weight 54 g / m ² ), using a polyester-based adhesive (S-3911 Toa Gosei Chemical Industry Co., Ltd.) as a support, laminating and laminating these three layers. Thus, a base layer sheet for a thermal transfer image receiving sheet was obtained.

Example 3 Yupo FPG80 (80 μm thick) which is a biaxially stretched multi-layer film mainly composed of a polyolefin containing an inorganic pigment
m, Oji oil-based synthetic paper) as the front side resin coating layer, YUPO FPG110 (thickness 110 μm, Oji oil-based synthetic paper) as the back side resin coating layer, and 20 μm PET (polyethylene terephthalate) as the support , Polyester adhesive (S
(3911 Toa Gosei Chemical Industry Co., Ltd.), and the three layers were laminated and laminated by dry lamination to obtain a base layer sheet for a thermal transfer image receiving sheet.

Example 4 A toluene solution of a polyester resin (Vylon 200 Toyobo) was applied on the surface-side resin coating layer of the base sheet obtained in Example 1, and dried to form a 5 g / m ² image-receiving layer. An image receiving sheet for a sublimation transfer printer was obtained.

Example 5 An image receiving layer of 5 g / m ² was formed in the same manner as in Example 4 using the base sheet obtained in Example 2 to obtain an image receiving sheet for a dye sublimation transfer printer.

Example 6 An image receiving layer of 5 g / m ² was formed in the same manner as in Example 4 using the base sheet obtained in Example 3 to obtain an image receiving sheet for a dye sublimation transfer printer.

Comparative Example 1 Yupo FPG80 (80 μm thick) which is a multi-layered film biaxially stretched with a polyolefin containing an inorganic pigment as a main component
m, Oji oil-based synthetic paper) and YUPO FPG110 (thickness 110)
μm, Oji Yuka Synthetic Paper) and a polyester adhesive (S3911 Toagosei Chemical Industry) by dry lamination and lamination to obtain a base layer sheet for a thermal transfer image receiving sheet.

Comparative Example 2 A 75 μm OPP film was used as it was as a base sheet for a thermal transfer image receiving sheet.

Comparative Example 3 Yupo FPG150 (thickness: 150) which is a multi-layered film biaxially stretched with a polyolefin containing an inorganic pigment as a main component.
μm, Oji Oil Chemical Synthetic Paper) was used as it is as a base sheet for a thermal transfer image receiving sheet.

Comparative Example 4 Yupo FPG80 (80 μm thick), which is a biaxially stretched multi-layer film mainly composed of a polyolefin containing an inorganic pigment.
m, Oji oil-based synthetic paper) as the resin coating layer on the front side and the coating layer on the back side, and use high quality paper (OK foam paper Oji Paper Yonetsubo)
Using a polyester adhesive (S-3911 Toa Gosei Chemical Industry Co., Ltd.) as a support, these three layers are laminated and laminated using 64 g / m ² , a thickness of 56 μm, and a thermal shrinkage rate of 0.1% as a support. A base sheet for an image receiving sheet was obtained.

Comparative Example 5 In the same manner as in Example 4 using the base sheet of Comparative Example 1,
An image receiving layer of 5 g / m ² was formed to obtain an image receiving sheet for a dye sublimation type thermal transfer printer.

Comparative Example 6 An image receiving layer of 5 g / m ² was formed in the same manner as in Example 4 using the base layer sheet of Comparative Example 2 to obtain an image receiving sheet for a dye sublimation type thermal transfer printer.

Comparative Example 7 An image receiving layer of 5 g / m ² was formed in the same manner as in Example 4 using the base sheet of Comparative Example 3 to obtain an image receiving sheet for a dye sublimation type thermal transfer printer.

Comparative Example 8 Using the base layer sheet of Comparative Example 4, 5 g / m
The image receiving layer of No. ² was formed to obtain an image receiving sheet for a dye sublimation type thermal transfer printer.

The image receiving sheets of Examples 4 to 6 and Comparative Examples 5 to 8 were subjected to thermal transfer printing using a commercially available thermal transfer printer (trade name: CHC-35, manufactured by Shinko Electric Co., Ltd.). The quality of the image of the obtained print and the state of curl were observed, and evaluated according to the following five grades. Further, the image receiving sheet was heated at 120 ° C. for 10 minutes, the occurrence of thermal curl was observed, and this was evaluated on a five-point scale. Class evaluation contents 5 Excellent 4 Good 3 Normal 2 Slightly poor 1 Bad Evaluation results are shown in Table 1.

Further, the image receiving sheet was subjected to a print test by using a commercially available sublimation dye transfer video printer (trade name: VY-50, manufactured by Hitachi, Ltd.). The results were evaluated on a five-point scale in the same manner as above, and the results are shown in Table 2.

[Effects of the Invention] The thermal transfer image receiving sheet using the base layer sheet of the present invention is excellent in both image clarity and homogeneity, and the occurrence of curl after printing and during heating is significantly reduced. In addition, the present invention enables the use of a compact full-color printer for thermal transfer such as a sublimation transfer system, which greatly contributes to the industry.

[Brief description of the drawings]

FIG. 1 is an explanatory cross-sectional view showing a configuration of an embodiment of a base layer sheet for a thermal transfer image receiving sheet according to the present invention, and FIG. 2 is a thermal transfer image receiving sheet obtained using the base layer sheet of the present invention. FIG. 2 is an explanatory cross-sectional view illustrating a configuration of one embodiment. DESCRIPTION OF SYMBOLS 1 ... Support, 2 ... Front side resin coating layer, 3 ... Back side resin coating layer, 4 ... Base layer sheet, 5 ... Image receiving layer, 6 ... Thermal transfer image receiving sheet.

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Masaru Kato 1-10-6 Shinonome, Koto-ku, Tokyo Oji Paper Manufacturing Co., Ltd. (72) Inventor Kenji Yasuda 1-10-6, Shinonome, Koto-ku, Tokyo Oji Paper Co., Ltd. Product Research Laboratory (56) References JP-A-62-198497 (JP, A) JP-A-63-290790 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) B41M 5/40

Claims (1)

(57) [Claims] 1. A sheet-like support having a thickness of 20 to 300 .mu.m, and a biaxially stretched multi-layered resin film containing a polyolefin resin as a main component and a biaxially stretched film on its surface (the surface on which an image receiving layer is formed) and on its back surface. And a backside resin coating layer formed by laminating and adhering, and a thickness X ₁ (μm) of the resin film for forming the front side resin coating layer.
m) and the thickness X ₃ (μm) of the resin film for forming the backside resin coating layer satisfy the following relationship: 10 ≦ X ₃ −X ₁ ≦ 40 Base layer sheet for receiving sheet.