JPH0672053A - Thermal transfer dye accepting sheet - Google Patents

Abstract

PURPOSE:To provide a cut thermal transfer dye-accepting sheet at low costs which forms images of high density and high quality when used in a dye thermal transfer printer and little curls after printing. CONSTITUTION:The thermal transfer dye-accepting sheet has a supporting body of a sheet mainly composed of cellulose pulp, a surface coating layer formed on one surface of the supporting body and mainly composed of a thermoplastic resin, an image receiving layer formed on the surface coating layer and a rear face coating layer formed on the opposite surface of the supporting body and mainly composed of a thermoplastic resin. The sheet is cut into pieces so that the images are recorded in the lateral direction of the supporting body regulated by JISP0001, No.4015.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a dye thermal transfer receiving sheet (hereinafter simply referred to as a receiving sheet).
More specifically, the present invention, in a thermal (thermal recording) printer, particularly a dye thermal transfer printer, accepts an image-forming dye such as a thermally transferred sublimable dye and produces a clear image without causing noise and curl. The present invention relates to a receiving sheet that can be printed with high sensitivity.

[0002]

2. Description of the Related Art Recently, a thermal printer, especially a dye thermal transfer printer capable of printing a clear full-color image has been attracting attention. A dye thermal transfer printer overlays a sublimation dye ink sheet with a receptive layer containing a dye-dyeable resin of a receptive sheet, and receives heat from a thermal head or the like at a predetermined concentration of a dye in a required portion of the sublimation dye layer. It is transferred onto a layer to form an image.

In order to form a high-quality print on a receiving sheet at high speed with such a thermal printer,
It is necessary to provide a receiving layer containing a dye-dyeing resin as a main component on the base material.

It is known that a biaxially stretched film containing a thermoplastic resin such as polyolefin as a main component and containing voids (voids) is used as a base material of the receiving sheet. A receiving sheet based on a biaxially stretched film has advantages such as a relatively uniform thickness and flexibility, and further, has a smaller thermal conductivity than paper made of cellulose fiber, so that it is uniform. It has the advantage that high-density prints can be obtained.

However, when such a biaxially stretched film is used as a base material of a receiving sheet, the generation of fine noise due to the void structure existing on the surface has been a problem.
In addition, the residual stress during stretching is returned by the heat during printing and heat shrinks in the stretching direction, resulting in curls and wrinkles on the receiving sheet, causing troubles such as paper jams in the running of the sheet, and There was a drawback that markedly reduced the commercial value.

In order to improve these drawbacks, it has been used as a laminated base material in which stretched films are laminated and adhered on both sides of a core material having a relatively small heat shrinkage rate or a core material having a large elastic modulus. However, this method not only raises the cost but also stacks sheets having different shrinkage rates, so that curl caused by the difference in shrinkage rate always remains a problem.

Various efforts have hitherto been made to improve the above-mentioned drawbacks. In particular, a large number of receiving sheets using a sheet-like support containing cellulose pulp as a main component have been proposed because a feeling of touch and a feeling of mass close to those of a photograph are required.

For example, Japanese Patent Application Laid-Open No. 62-21590 discloses a method in which a paper made of cellulose pulp is used as a sheet-like support, an organic polymer barrier layer is provided on the sheet-like support, and the sheet is used as a substrate. Further, a so-called resin-coated paper is provided by providing a coating layer containing a thermoplastic resin, especially polyethylene as a main component on both sides of a sheet-like support made of paper mainly containing cellulose pulp, which has been conventionally used in silver salt photography. (Hereinafter, simply referred to as RC paper) and using this as a base material is an attempt similar to the above.

US Pat. No. 4,774,224 discloses surface roughness Ra.
It has been proposed to use a resin-coated paper having a small size as a base material of a receiving sheet. Although the curl after printing is improved by this proposal, there are problems that a transfer dropout occurs and a sufficient transfer density cannot be obtained. In addition,
The RC papers exemplified in 1-267090 have not only the problem that the gloss of the printed part deteriorates, but also the problem that the transfer density is low.

Normally, the receiving sheet is used in a cut sheet (cutting sheet) state, and in the printer, this cutting receiving sheet is defined in the longitudinal direction defined by JIS P 0001, No. 4011 (hereinafter simply referred to as the longitudinal direction). It is installed so that it can be recorded and run. In the receiving sheet recorded in this direction,
If the resin coating layer is thinned in order to increase the transfer density, the concavities and convexities on the surface of the sheet-shaped support due to the cellulose fibers are not completely concealed, and transfer omission occurs due to poor adhesion between the receiving sheet and the thermal head, There is a problem that a good image cannot be obtained.

[0011]

DISCLOSURE OF THE INVENTION The present invention has the drawbacks of the prior art, that is, noise and curl problems when using a void-containing biaxially stretched film, and transfer loss and transfer when using RC paper. It is an object of the present invention to provide a cut dye thermal transfer receiving sheet which eliminates the lack of density, is inexpensive, has excellent image quality, and has a high transfer density.

[0012]

A dye thermal transfer receiving sheet according to the present invention comprises a sheet-like support containing cellulose pulp as a main component, and a surface coating formed on one surface thereof and containing a thermoplastic resin as a main component. A cut dye having a layer, an image receiving layer formed on the surface coating layer, and a back coating layer formed on the opposite surface of the sheet-like support and containing a thermoplastic resin as a main component. A thermal transfer receiving sheet, characterized in that the sheet is cut so that the recording run is performed in the lateral direction of the sheet-like support defined by JIS P 0001, No. 4015.

[0013]

The cut receiving sheet of the present invention, when mounted on a printer, can be recorded and run in the lateral direction of the sheet-like support defined by JISP 0001, No. 4015 (hereinafter simply referred to as lateral direction). It was cut as follows. There are irregularities on the surface of the receiving sheet due to the cellulose fibers of the sheet-like support, and these irregularities affect the adhesion between the thermal head and the receiving sheet, and as a result, transfer defects occur. By performing recording traveling in the lateral direction of the sheet-shaped support, the adhesion between the thermal head and the surface of the receiving sheet is improved, transfer omission is improved, and it becomes possible to improve the sensitivity by thinning the surface coating layer, A high-quality, high-sensitivity receiving sheet can be obtained.

As described in JIS P 0001, No. 4015, the lateral direction is the direction of the paper perpendicular to the traveling direction of the paper when a sheet-shaped support (paper) is made by a paper machine. say. The receiving sheet of the present invention has
It is cut into a predetermined size and direction so that it is performed in the lateral direction.

The pulp used in the production of the sheet-shaped support of the present invention is not particularly limited, but for example, wood pulp, waste paper pulp obtained by subjecting hardwoods and conifers to chemical treatment or mechanical treatment, Examples include non-wood natural pulp such as hemp and cotton, and synthetic pulp made from polyethylene, polypropylene and the like. These pulps may be used alone or in combination of several kinds.

In addition to the above pulp, organic fibers such as acrylic fibers, rayon fibers, phenol fibers, polyamide fibers, polyester fibers, glass fibers and carbon fibers,
Although various fibers such as inorganic fibers such as alumina fibers may be mixed and mixed, a sheet containing 50% by weight or more of pulp is preferable from the viewpoint of papermaking property.

In the step of making a sheet-shaped support, various retention aids, paper strength enhancers, sizing agents and fillers may be appropriately selected and added, and further dyes, pH adjusters and slime control agents may be added. A defoaming agent or the like may be added if necessary. Further, starch, polyvinyl alcohol, a surface sizing agent, a pigment or the like may be applied to the surface of the sheet-shaped support with a size press, a gate roll, a blade coater, an air knife coater or the like.

Further, it is advantageous to carry out calendering using a machine calender, super calender, thermal calender or the like after paper making. The basis weight of the sheet-shaped support is not particularly limited, but is preferably 60 to 250 g / m ² .

The resin for forming the surface coating layer and the back coating layer which can be used in the present invention is a thermoplastic resin which can be extrusion coated, and is, for example, a homopolymer of low density polyethylene, high density polyethylene, polypropylene, polybutene, polypentene and the like. Polymer, or ethylene
A copolymer composed of two or more olefins such as a polypropylene copolymer, a linear low-density polyethylene which is a copolymer of ethylene and an α-olefin, and a mixture thereof, and having various density and melt index The substances can be used alone or as a mixture thereof.

The thermoplastic resin used for the surface coating layer and the back coating layer may contain a white pigment. White pigments such as titanium dioxide, zinc sulfide, zinc oxide, calcium sulfate, calcium sulfite, barium sulfate, clay, calcined clay, talc, kaolin, calcium carbonate, silica, calcium silicate, etc. You are free to choose more than what is known for use. Further, various antioxidants, pigments and dyes such as cobalt blue and ultramarine blue, optical brighteners, ultraviolet absorbers, antiblocking agents, slip agents, etc. are appropriately combined and added to the surface coating layer and / or the back coating layer. Good.

The surface coating layer and the back coating layer in the present invention are formed by a melt extrusion laminator,
The obtained coating layer preferably has good surface flatness and adhesiveness to a sheet-like support. Preferably the coating amount of the surface coating layer is 5 to 80 g / m ^2, more preferably from 10~35g / m ^2. Coating amount is 5g / m
^If it is less than ² , a transfer failure occurs and a good image cannot be obtained. If it exceeds 80 g / m ² , a sufficient transfer density may not be obtained. Further, an anchor coat layer, an adhesive layer, and a thermoplastic resin layer may be provided between the sheet-shaped support and the surface coating layer and between the sheet-shaped support and the back surface coating layer.

As the resin used in the image-receiving layer of the receiving sheet of the present invention, those having good dye-receiving property, high transfer speed, high image density, little discoloration due to heat, and good running property can be used. Required. Specifically, it is formed of a polyester resin, a polycarbonate resin, a vinyl chloride copolymer, a resin cured by irradiation with active energy rays, or the like.

In the image receiving layer, it is usual to add a crosslinking agent for the resin, a lubricant, a release agent, a pigment, etc., if necessary, for the purpose of preventing fusion with the ink sheet due to heat during printing. is there. If necessary, other additives such as pigments, fluorescent dyes, dyes such as blue and violet, ultraviolet absorbers, and antioxidants can be added. These additives may be mixed and coated with the main component of the image receiving layer, or may be coated as a separate coating layer on or under the coating layer.

A layer containing an antistatic agent may be provided on at least one surface of the receiving sheet in order to prevent running troubles due to static electricity generated during running of the receiving sheet in the printer. A cationic hydrophilic polymer is advantageously used as the antistatic agent.

The image receiving layer and other coating layers of the receiving sheet of the present invention are coated with a coater such as a bar coater, a gravure coater, a blade coater, an air knife coater, a comma coater, a gate roll coater, and dried. It is formed. The thickness of the image receiving layer of the receiving sheet of the present invention is preferably 1 to 10 μm, more preferably 2 to 6 μm. If the thickness of the image receiving layer is less than 1 μm, the density and sensitivity of the image may be lowered, or the gloss of the printed surface may be lowered.
If it is thicker than 10 μm, the effect is saturated, which is uneconomical and the strength of the receiving layer may be lowered.

[0026]

The present invention will be described in more detail with reference to the following examples. Of course, the present invention is not limited to these. In addition, "parts" and "%" in the examples all represent "parts by weight" and "% by weight".

Example 1 A resin consisting of 90 parts of polyethylene for a surface coating layer and 10 parts of titanium oxide and a resin consisting of 100 parts of polyethylene for a back coating layer were extrusion coated on the front and back of a high-quality paper having a basis weight of 150 g / m ^2. Then, the front and back coating layers were provided. Next, after corona treatment is applied to the surface of the surface coating layer, a receiving layer-forming composition having the following composition is applied by a Meyer bar so that the solid content is 6 g / m ² , and dried. A cutting receiving sheet that can be mounted on a printer so as to record and run in the lateral direction was obtained.

The receptor layer forming composition Ingredient weight polyester resin (Toyobo Co., trade: Byron 200) 100 parts Silicone oil (Shin-Etsu Silicone Co., Ltd., trademark: KF393) 3 parts Isocyanate (manufactured by Takeda Pharmaceutical, Trademark: Takenate D-110N) 5 parts Toluene 300 parts

Example 2 The same operation as in Example 1 was performed. However, a receiving sheet was obtained by using a coated paper having a basis weight of 120 g / m ² as the sheet-shaped support.

Example 3 The same operation as in Example 1 was performed. However, a receiving sheet was obtained using a resin composed of 100 parts of polypropylene as the surface coating layer.

Comparative Examples 1 to 3 The same operations as in Examples 1 to 3 were performed. However, the receiving sheet was cut so as to be attached to the printer so that the recording and running could be performed in the longitudinal direction of the on-sheet support.

Performance Test Each receiving sheet obtained in each of Examples 1 to 3 and Comparative Examples 1 to 3 was evaluated for print density of a printed image, transfer omission, and curl of the receiving sheet after printing. The print density, transfer omission, and curl of the receiving sheet after printing were evaluated as follows.

(1) Print density Color bar signal generator (manufactured by Shibazok Co., Ltd., trademark: C13A)
The step pattern according to 2) is printed by a dye thermal transfer printer (Sony, trademark: UP3000), and the maximum density of the printed image is measured by a Macbeth densitometer (RD-914,
Kollmorgen Corp.).

(2) Transfer omission For the print image used for the evaluation of the print density, the transfer omission is subjected to a sensory evaluation by observation, and the result is 3 for a good result, 2 for a general quality, and 1 for a poor quality. , And three levels are displayed.

(3) Curling degree after printing A black solid pattern is printed using a receiving sheet having a size of 14 cm × 10 cm, and the printed surface of the receiving sheet is placed upward on a flat surface, and the four corners of the receiving sheet are flat. The height from was measured and evaluated for the maximum height.

The test results are shown in Table 1.

[Table 1]

[0037]

According to the present invention, the curl resistance is improved,
It is possible to obtain a dye thermal transfer receiving sheet having excellent print image quality at a low cost, which largely contributes to the industrial world.

Claims (1)

[Claims] 1. A sheet-shaped support containing cellulose pulp as a main component, a surface coating layer formed on one surface thereof and containing a thermoplastic resin as a main component, and an image receiving material formed on the surface coating layer. A cut dye thermal transfer receiving sheet having a layer and a back coating layer formed on the opposite surface of the sheet-like support and containing a thermoplastic resin as a main component, which is JIS P 0001, No. 4015. In order to perform recording traveling in the lateral direction of the sheet-like support defined by
A dye thermal transfer receiving sheet characterized by being cut.