JPH0761744B2 - Thermal transfer sheet - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of use] The present invention relates to an improvement in a heat-sensitive transfer sheet, and more particularly to a heat-sensitive transfer sheet that provides a presence or absence (end mark) of the heat-sensitive transfer sheet and a detection function as necessary. .

[Conventional technology]

Printers having a function of detecting the presence / absence of a thermal transfer sheet in the thermal printer and the remaining amount of the thermal transfer sheet often use a detection method based on light transmission. One example thereof will be described with reference to FIG.

In FIG. 3, the heat-sensitive transfer sheet is made almost transparent of the base film by wiping off the heat-melting ink 3 at a part of the sheet, and the light of the light source 4 is transmitted to this transparent portion to allow the photoelectric tube 5 to pass through. To detect. This portion is often referred to as an "end mark" 6 to inform the remaining amount of the thermal transfer sheet. However, it is often seen in a color having a high transmittance in a multicolor thermal printer, particularly a color other than black and having a low density.
Since there is a small difference in the transmittance between the portion 7 other than the end mark where the ink is applied and the portion 7 where the ink is applied, it may become undetectable or unstable even by the photoelectric tube 5. That is, to be more specific, "ribbon (normal thermal transfer sheet is referred to as ribbon)" is used to notify that the thermal transfer sheet has been lost because light is always transmitted even in the portion 7 other than the end mark.
The printer may stop running due to the "empty" condition.

[Problems to be solved by the invention]

Therefore, the present invention solves the above-mentioned drawbacks of the prior art and provides a heat-sensitive transfer sheet having a function capable of detecting the presence or absence of the heat-sensitive transfer sheet (end mark detection possible).

Structure of the Invention [Means for Solving Problems] In the present invention, in a heat-sensitive transfer sheet having a heat-fusible ink layer on an intermediate layer provided on a base film, the intermediate layer has a light-shielding property. In addition to the above, the light transmittance of the entire heat-sensitive transfer sheet including the ink layer and the base film is set to 10% or less, and it is an object of the present invention to solve the above-mentioned problems of the prior art.

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

FIG. 1 is a diagram showing an embodiment of the present invention. Referring to FIG. 1, the present invention relates to a heat-sensitive transfer sheet comprising a base film 1, an intermediate layer 2 and a heat-fusible ink layer 3. The intermediate layer 2 contains a pigment or a dye. The purpose is to give the ribbon (heat-sensitive transfer sheet) a light-shielding property.

As the base film, commonly used plastic films such as polyester, polypropylene, cellophane, acetate and polycarbonate, and papers such as condenser paper and paraffin paper are used. Polyester film is the best choice.

The hot-melt ink is prepared by blending a colorant, EVA, paraffin wax, carnauba wax and the like. As the colorant, in addition to the colorants forming cyan, magenta, yellow, and black, colorants of various other colors can also be used. That is, the heat fusible ink is a pigment or dye shown below as a colorant, which is selected and added in a required amount according to the color or density to be applied to the heat fusible ink.

Pigments Inorganic pigments Titanium oxide, zinc white, lithopone, lead white, carbon black, red lead, red iron oxide, yellow lead, navy blue, molybdenum red, zinc chromate, iron black, etc. Organic pigments lake red C, fast sky blue, dye lake,
Phthalocyanine Blue, Benzidine Yellow, Priliant Carmine 6B, Lake Red 4R, Lake Red D, Fast Yellow 10G, Resol Red R, Watching Red, Priliant Carmine 3B, Priliant Scarlet G, Phthalocyanine Green, Lake Bond 10B,
Dyes such as diamond black, bon maroon, nitroso dye, nitro dye, azo dye, azoic dye, stilbene dye, diphenylmethane dye, triallylmethane dye, xanthene dye, acridine dye, quinoline dye, methine and polymethine dye, thiazole dye, azine dye, Oxazine dye, thiazine dye, sulfur dye, lactone dye, aminoketone and hydroxyketone dye, anthraquinone dye, indigoid dye, phthalocyanine dye, etc. 0.1 to 30μ is suitable.

The intermediate layer, which is a feature of the present invention, must have the following characteristics.

(1) Light-shielding property ... Necessary to enable detection only at the end mark part. Specifically, by providing the matte layer with a light-shielding property, the entire heat-sensitive transfer sheet including the ink layer and the base film is shielded from light, so that such an end mark detection function can reliably exert its effect. That is, the total color density (light-shielding property) of the heat-fusible ink layer 3 and the matte layer 2 becomes a problem. Here, it is a matter of how much light-shielding property is given to the matte layer, but this is determined by the thermal printer to be used. This will be described with reference to FIG.

In FIG. 2, if the built-in photoelectric tube 5 functions and can be detected when the light transmittance of the end mark portion 6 becomes 10% or more, the portion 7 other than the end mark of the thermal transfer sheet used for this Is a light transmittance of 10% or less (2%
In view of the margin, it is effective to have a light-shielding property so that the margin is 8% or less. At this time, the light-shielding property (color density) imparted to the mat layer 2 varies depending on the color density of the heat-fusible ink layer 3.

(2) Heat resistance ... When the intermediate layer is softened or melted by the heat of the thermal head, firstly heat energy is lost, which causes a decrease in sensitivity, and secondly, the intermediate layer and the heat-meltable ink layer. When the tackiness of the intermediate layer changes due to a change in the degree of adhesion, there is a problem that uneven transfer occurs due to the ink ribbon remaining.

(3) Heat releasability: It is necessary that the peelability during heating be good between the intermediate layer and the heat-meltable ink layer.

In order to obtain the above characteristics (1) to (3), the intermediate layer is made of the following materials. (C) Matting agent is optional) A) Resin A synthetic resin having a glass transition point of 60 ° C. or higher is suitable.
Typical examples are acrylic resin, polyester resin, phenol resin, fluororesin, polyimide resin, methylmethacrylate resin, vinylidene fluoride resin, vinylidene fluoride-tetrafluoroethylene copolymer resin, polyvinyl fluoride resin, acrylonitrile-styrene. Such as a copolymer resin.

A resin obtained by adding a compound having two or more amino groups or diisocyanate or triisocyanate to a thermoplastic resin having an OH group or a COOH group is also suitable.

Thermoplastic resins having OH groups or COOH groups include polyester resins, vinyl chloride / vinyl acetate copolymers, polyether resins, polybutadiene resins, acrylic polyols, OH
A urethane or epoxy prepolymer having a group, a nitrocellulose resin, a cellulose acetate propionate resin, a cellulose acetate butyrate resin, or a cellulose acetate resin is preferably selected. These resins are OH
In addition to those having a group or COOH group in its polymerized unit,
It may have a terminal or a side chain.

Examples of the diisocyanate added to the thermoplastic resin having the above OH group or COOH group, paraphenylene diisocyanate, 1-chloro-2,4-phenyl diisocyanate,
2-chloro-1,4-phenyl diisocyanate, 2,4-toluene diisocyanate, 2,6-toluene diisocyanate, 1,5-naphthalene diisocyanate, hexamethylene diisocyanate and 4,4'-biphenylene diisocyanate, examples of triisocyanates Is triphenylmethane triisocyanate and 4,4 ′, 4′-
Trimethyl-3,3 ', 2'-triisocyanate-2,4,6-
It is triphenyl cyanurate. In addition, 2 amino groups
Examples of compounds having more than one are melamine, methylated melamine, methylated methylol melamine, butylated melamine,
Butylated methylolmelamine, dicyandiamide, guanidine, biguanide, diaminomelamine, guanylmelamine, urea, biuret, ammeline, ammelide, butylated urea and methylated urea, and the guanamines formoguanamine, acetoguanamine, benzoguanamine, phenylacetoguanamine. , Methoxyguanamine and N-methylol acrylamide copolymer polymers can also be used.

When a compound having two or more amino groups is used, ammonium phosphate, triethanolamine, acetamide, urea, pyridine, paratoluenesulfonic acid, sulfanilic acid, guanidine stearate, guanidine carbonate, etc. are used as a curing catalyst. To do.

The diisocyanate, trisocyanate, and amino compound may be used alone or in combination of two or more to form an OH group or
5-40 with respect to 100 parts by weight of the thermoplastic resin having a COOH group
Add parts by weight, preferably 10 to 20 parts by weight. As a cross-linking agent, they moderately cure the intermediate layer and increase the adhesive force of the intermediate layer to the plastic film.

B) Thermal release agent or lubricant As a substance that enhances the releasability between the intermediate layer and the hot-melt ink layer when heated, there are those that exhibit this performance by being melted by heating, and those that work as a solid powder. .

Polyethylene wax belongs to the former group,
Waxes such as paraffin wax, amides, esters and salts of higher fatty acids, and phosphoric acid esters such as higher alcohols and lecithin. The latter group includes Teflon, fluororesins such as polyvinyl fluoride, guanamine resins, boron nitride, silica, wood flour, talc and the like. The fact that two groups can be used together
Of course.

The amount used is such that the above thermal release agent or lubricant accounts for 10 to 50% by weight in the intermediate layer.

C) Matting agent An appropriate amount of the following inorganic pigments is used.

Silica, talc, calcium carbonate, precipitated barium sulfate, alumina, acid clay, clay, magnesium carbonate,
Carbon black, tin oxide, titanium white, etc.

Some of them overlap with the above-mentioned thermal release agent or lubricant, and they also have the functions of B) and C).

D) Colorant In addition to the colorants forming cyan, magenta, yellow and black, colorants of various other colors can also be used.

That is, in the intermediate layer, the pigments or dyes shown below as colorants are selected and added in a required amount according to the color or concentration to be applied to the intermediate layer.

Pigments Inorganic pigments Titanium oxide, zinc white, lithopone, lead white, carbon black, red lead, red iron oxide, yellow lead, navy blue, ultramarine blue, molybdenum red, zinc chromate, iron black, etc. Organic pigments lake red C, fast sky blue, dyed lake ,
Phthalocyanine Blue, Benzidine Yellow, Brilliant Carmine 6B, Lake Red 4R, Lake Red D, Fast Yellow 10G, Resol Red R, Watching Red, Brilliant Carmine 3B, Brilliant Scarlet G, Phthalocyanine Green, Lake Bond-10B,
Dyes such as diamond black, bon maroon, nitroso dye, nitro dye, azo dye, azoic dye, stilbene dye, diphenylmethane dye, triallylmethane dye, xanthene dye, acridine dye, quinoline dye, methine and polymethine dye, thiazole dye, azine dye, Oxazine dyes, thiazine dyes, sulfur dyes, lactone dyes, aminoketone and hydroxyketone dyes, anthraquinone dyes, indigoid dyes, phthalocyanine dyes, etc. When matte printing is not required, the above-mentioned C) matting agent and the above-mentioned dyes instead of pigments are used. It should have a light-shielding property.

The formation of the intermediate layer on the base film is carried out by dissolving or dispersing the above-mentioned constituent materials in an appropriate solvent to adjust the viscosity suitable for coating, and then applying it to the base film using a conventional coating means.

The heat-sensitive transfer sheet of the present invention may include various modifications. One example is to provide a primer layer on the base film to enhance the adhesion between the base film and the intermediate layer. The primer layer can be easily prepared by applying a known primer dye. For example, acrylic resin, polyester resin, polyvinyl acetate resin, vinyl chloride / vinyl acetate resin, polyol and dithocyanate, polyol and melamine, or a combination of epoxy resin and diisocyanate may be used as the binder,
When the base film is polyester, the primer coating using these binders has a remarkable improvement in adhesive strength.

Another example is to provide a layer for preventing sticking between the base film and the thermal head, which may occur depending on printing conditions. The sticking prevention layer has a resin and a thermal release agent or a lubricant as basic constituent components. A coating composition may be prepared using the same materials (excluding the matting agent and the colorant) as those used for forming the intermediate layer, and the composition may be applied to the other surface of the base film.

[Action]

Since there is a light-shielding intermediate layer on the base film, there is a clear difference in the light transmittance between the near-transparent end mark part and the part other than the end mark that has sufficient light-shielding property. Become. In other words, by providing such an intermediate layer, the difference in light transmittance becomes larger than that in the case of only the base film and the heat-meltable ink layer. Therefore, the end mark detection function can be surely operated without being unclear or unstable as in the conventional case, and the user can be surely informed that the remaining amount of the thermal transfer sheet has become very small.

Further, if a matting agent and a pigment are used in the intermediate layer, matte printing can be performed by the matting effect. In contrast,
If a dye is added to the intermediate layer without adding a matting agent and a pigment, glossy printing can be performed. Further, a complementary color function is produced by making the heat-meltable ink layer and the intermediate layer have the same color.

〔Example〕

(Intermediate layer ink I) Polyester resin 6 parts by weight (Toyobo "Vylon 200") Vinyl chloride / vinyl acetate copolymer resin 7 parts by weight (UCC "Vinylite VAGH" carbon black 5 parts by weight (Tokai electrode "SEAST SO") Methyl ethyl ketone 30 parts by weight Toluene 30 parts by weight To the above composition, a 50% butyl acetate solution of isocyanate (Takeda Pharmaceutical Co., Ltd. "Takenate D-204") is added to the above composition: isocyanate = 20: 3 (weight ratio, the same applies hereinafter). The mixture of the inks is used as the intermediate layer ink I.

(Matt layer ink II) Methyl methacrylate resin 10 parts by weight (Mitsubishi Rayon "Dianarl BR-88") Polyethylene wax 2 parts by weight (Asahi Denka "Mark FC-113" 30% Torunene dispersion) Blue dye 4 parts by weight (Orazol Blue BLW Special) CIBA Geigy Toluene 20 parts by weight Methyl ethyl ketone 20 parts by weight (Primer layer ink) Polyester resin 3 parts by weight (Toyobo "Vylon 200") Vinyl chloride / vinyl acetate copolymer resin 3 parts by weight (UCC's "Vinylite VAGH") ) Toluene 20 parts by weight Methyl ethyl ketone 20 parts by weight The above primer ink composition was mixed with an isocyanate (Takenate D-110N, Takeda Pharmaceutical Co., Ltd.) at a ratio of 46: 1 to prepare a primer layer ink.

(Heat-melting ink I) Paraffin wax 10 parts by weight Carnauba wax 10 parts by weight Ethylene / vinyl acetate copolymer 1 part by weight (Sumitomo Chemical "Smitate HC-10") Yellow pigment (Dainichi Seika 2400) 2 parts by weight (heat Melt Ink II) 2 parts by weight of the yellow pigment (Dainichiseika 2400) of the above heat-meltable ink I is replaced with 2 parts by weight of a red dye (CIBA Geigy "Orazol Primitive Scarlet 3B").

The compositions of the hot melt inks I and II were kneaded with a blade kneader at 100 ° C. for 6 hours.

Example 1 Polyethylene terephthalate (Toray) having a thickness of 6 μm was used as a base film, and the intermediate layer ink I was applied by a gravure printing method at a coating amount of 1 g / m ² . Onto the intermediate layer ink I, the above heat-meltable ink I was applied to a thickness of 5 μm by a roll coating method by a hot-melt method heated to 100 ° C. to form a heat-sensitive transfer ink layer.

Example 2 Polyethylene terephthalate (Toray) having a thickness of 6 μm was used as a base film, and the primer layer ink was applied by a gravure printing method at a coating amount of 0.5 g / m ² . The intermediate layer ink II was applied onto this primer layer by a gravure printing method at a coating amount of 1 g / m ² . Further, the heat-meltable ink II was applied onto the intermediate layer ink II by a roll-coating method by heating at 100 ° C. to a thickness of 5 μm to form a heat-sensitive transfer ink layer.

Comparative Example 1 The heat-sensitive transfer sheet of Example 1 without the intermediate layer ink I.

Comparative Example 2 A thermal transfer sheet obtained in Example 2, except that the intermediate layer ink II is not provided.

The heat-sensitive transfer sheets of Examples 1 and 2 and Comparative Examples 1 and 2 described above were slit into ribbons, and the mat layer and ink layer at the terminal end were wiped off to obtain commercially available end mark detection functions as described above. It was printed by the printer I had.

High-quality paper to be transferred (Mitsubishi Paper Mills "Tokuryoishi" 46th Edition / 7
2 Kg) Thermal head Thin film type thermal head Printing energy 1 mJ / dot (4 × 10 ⁻⁴ cm ² ) Next, the effects of matte printing and end mark detection by the heat-sensitive transfer sheet of the present invention are shown below. (Table.1) Generally, the matte level required for printing varies depending on the gloss level of the recording paper and the reading conditions, but if the gloss level measured with a gloss meter is about 30 or less, it is always at a sufficient level. Can be said to be. With the present invention, this can easily be achieved. In Table.1, if glossiness is 30 or less, ○, 30
If it is above, it is marked as ×. The effect of being able to detect the end mark is "ribbon empty" after the ribbon is set, and x indicates that it does not run, and "ribbon empty" indicates that there is no problem and the ribbon detection mark is at the position of the ribbon detection mark. In addition, although the glossiness judgments of Examples 1 and 2 are ◯ and X, when matte printing is required,
In the case where gloss printing is required, the case of Example 1 is changed to that of Example 2.
You can use the ones that are up to you.

[Advantages of the Invention] By using the heat-sensitive transfer sheet of the present invention, it is possible to perform heat-sensitive transfer having the functions of detecting end marks and, if necessary, matte printing, glossy printing, and complementary color.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of the heat-sensitive transfer sheet of the present invention, FIG. 2 is a block diagram for explaining the principle of the present invention, and FIG. 3 is a conventional heat-sensitive transfer sheet for FIG. It is a block diagram. In the figure, 1 is a base film, 2 is an intermediate layer, 3 is a heat-meltable ink layer, 4 is a light source, 5 is a photoelectric tube, 6 is an end mark portion, and 7 is a portion other than the end mark.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Kyoichi Yamamoto 7-29-5 Sagamidai, Sagamihara City, Kanagawa Prefecture (72) Inventor Kyohei Takahashi 4-11 Minamidai, Sagamihara City, Kanagawa Prefecture 2-112 (56) References Special Features Kai 58-116193 (JP, A) JP 57-138984 (JP, A) JP 57-105382 (JP, A)

Claims (3)

[Claims] 1. A heat-sensitive transfer sheet comprising a base film, an intermediate layer provided on the base film, and a heat-meltable ink layer.
The intermediate layer has a light-shielding property, and the light transmittance of the entire heat-sensitive transfer sheet including the ink layer and the base film is 10%.
A heat-sensitive transfer sheet characterized by being: 2. The heat-sensitive transfer sheet according to claim 1, wherein the base film is provided with a primer layer and then an intermediate layer is provided to enhance the adhesive force between the base film and the intermediate layer. 3. The heat-sensitive transfer sheet according to claim 1, wherein the base film is a plastic film and a layer for preventing sticking to the thermal head is provided on the other surface.