JPS6287391A - Thermal transfer ribbon - Google Patents

Abstract

PURPOSE:To provide a thermal transfer ribbon capable of clear printing, by providing a releasable layer between a film form base and a heat-fusible ink layer, and forming the ink layer from a heat-fusible ink obtained by mixing a coloring agent with a binder agent comprising a ketone resin and an ethylene- vinyl acetate copolymer resin as main constituents. CONSTITUTION:A thermal transfer ribbon 10 is produced by providing a releasable layer 12 on a film form base 11 and providing a heat-fusible ink layer 13 thereon. The ink layer 13 comprises a coloring material and a binder agent. An inorganic or organic pigment and an oil-soluble or basic dye are used as the coloring material. In order to obtain a high melt viscosity and a high cohesive force, the binder comprises a ketone resin and an ethylene-vinyl acetate copolymer resin which are incompatible with each other as main constituents. The releasable layer 12 consists of a polyethylene wax, which has a low melt viscosity and is poor in affinity for the heat-fusible ink. Since the cohesive force of the ink itself is greater than the adhesive force between the releasable layer and the ink, clear printing free of blurring or voids can be achieved.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field 1] The present invention relates to a thermal transfer ribbon used in a printing device such as a thermal printer that performs printing by thermal transfer.

[Prior art] Printing using a thermal transfer ribbon is performed by bringing the thermal transfer ribbon into close contact with printing paper using a thermal head, and by causing a desired heating element among the many heating elements of the thermal head to generate heat, the thermal transfer ribbon is attached to the heating element. This is done by melting the heat-melting ink portion that is in contact with the support through the support and transferring it to the printing paper.

Conventionally, this type of thermal transfer ribbon has simply been coated directly onto a support with a heat-melting ink consisting of a colorant and a binder agent, and the binder agent has been mainly composed of wax.

[Problems to be Solved by the Invention] However, as described above, when printing is performed on plain paper using a thermal transfer ribbon that is simply coated with heat-melting ink directly on a support, the smoothness of the plain paper becomes Beck smooth. Sufficient print quality could not be obtained unless the printing time was maintained for several tens of seconds at a certain temperature.

The reason for this is that when the surface smoothness of the printing paper is low, as shown in Figure 2, the hot melt ink cannot come into contact with the recesses on the surface of the printing paper, and the ink transfer is not achieved, resulting in blurred printing. This is caused by the occurrence of gaps or omissions.

One possible way to solve this problem is to significantly lower the melt viscosity of the heat-melting ink, allowing the ink to penetrate from the contact areas of the convex parts of the printing paper and reach the non-contact parts of the concave parts. Such ink penetration occurs even in areas where the ink should not be transferred, making the outline of the transferred image unclear and giving it a smeared appearance.

[Objective of the Invention 1 The present invention was made in order to solve the problems of the conventional thermal transfer ribbon as described above, and its purpose is to print within the range of printing energy that can be sufficiently realized with the conventional thermal head. To provide a thermal transfer ribbon that can print clearly even on non-smooth printing paper without fading or being difficult to handle.

[Means for Solving the Problems] In order to achieve the above object, in the thermal transfer ribbon of the present invention, a release layer is interposed between the film-like support and the heat-fusible ink layer, The meltable ink layer is formed of a heat-meltable ink made by mixing a coloring agent and a binder whose main components are a ketone resin and an ethylene-vinyl acetate copolymer resin.

[Function] According to the above structure, the heat-melting ink melted by the heat from the thermal head is sufficiently fixed at the contact point of the convex portion of the printing paper during printing, and when the thermal transfer ribbon is peeled off, the heat-melting ink is sufficiently fixed to the support and the release layer or release layer when the thermal transfer ribbon is peeled off. Since the cohesive force of the thermofusible ink itself is greater than the adhesion between the paper and the thermofusible ink, the thermofusible ink in the non-contact areas corresponding to the recesses of the paper is also peeled off and transferred. be able to.

[Embodiment] An embodiment of the present invention will be described below with reference to FIGS. 1 to 3.

In FIG. 1, a thermal transfer ribbon 10 has a release layer 12 formed on a film-like support 11, and a heat-melting ink layer 13 further formed thereon.

The film-like support 11 used in this example is a film made of polyester, polyimide, polycarbonate, polysulfon, polyethersulfon, polyphenylene sulfide, polyether-etherketone, etc., which has a heat resistance temperature of 150'C or more. Alternatively, paper such as capacitor paper or glassine paper can be used, and the thickness is about 3~
It is desirable that the thickness be in the range of 20μ. Further, as shown in FIG. 1, an anti-sticking layer 14 made of a heat-resistant resin such as silicone resin is provided on the opposite side of the coated surface of the heat-fusible ink layer 13.

The heat-melting ink layer 13 is composed of a coloring material and a binder agent.

As the coloring agent, inorganic or organic pigments such as carbon black, lake red, alkali blue, and navy blue, and oil-soluble or basic dyes that are highly soluble in fatty acids such as nigrosine, oil black, and methyl violet are used.

Note that dyes are added as auxiliary agents to produce colors that cannot be produced by pigments alone, or to adjust the tone.

In addition, as a binder agent, in order to increase the melt viscosity and the cohesive force of the heat-melt ink itself at the transfer stage compared to the heat-melt ink layer of conventional thermal transfer ribbons, a ketone resin that is not compatible with each other is used. paraffin wax, microcrystalline wax, oxidized paraffin wax, candelilla wax, which has a melting point of 40 to 100'C, taking into consideration its melting point, melt viscosity, etc. Carnauba wax, montan wax, ceresin wax, polyethylene wax, oxidized polyethylene wax, castor wax, tallow hydrogenated oil, lanolin, wood wax, sorbitan stearate, sorbitan palmitate, stearyl alcohol, polyamide wax, oleylamide, stearylamide, hydroxy In addition to spiral materials such as stearic acid 9 synthetic ester wax and synthetic metal-containing wax.

Polyvinyl butyral, vinyl chloride-vinyl acetate copolymer resin, nitrocellulose, epoxy resin.

One or more resins such as ethylene-α-olefin copolymer resin, α-olefin-maleic anhydride copolymer resin, ethylene-methacrylic acid copolymer resin, and ethyl cellulose may be mixed. The coloring agent, ketone resin, and ethylene-vinyl acetate copolymer resin are 5 to 40 wt% and 20 to 20 wt%, respectively, based on the total amount of the hot-melt ink layer.
80wt%, 10-5Qwt% is suitable, and furthermore, 15-20wt%, 50-55wt%, 1Qwt%, respectively.
A blending amount of 5 to 25 wt% is desirable.

Further, the release layer 12 is made of polyethylene wax, which has a low melt viscosity and poor affinity with hot-melt ink.

Note that polyethylene wax alone may be used as the release layer 12, but fillers such as bentonite, phosphorus, and talc may be added to meet various requirements for the ink ribbon. , melt viscosity, etc. can be changed in a preferable direction.

Next, a manufacturing process for forming a release layer 12 and a hot-melt ink layer 13 on a support 11 having an anti-sticking layer 14 formed on the back surface will be explained based on this example.

(1) Formation step of release layer The polyethylene wax emulsion is diluted with water to form a coating liquid. In addition, when adding a filler, it is dispersed in the coating liquid using ultrasonic waves.

(2) Coating and drying process of release layer The coating solution is coated onto a film-like support 11, for example, a polyester film (thickness: 3.5 μm) using an appropriate coating device. Dry it at 80-100'C. In this example, the coating thickness was set to about 1 μm.

(3) Step of producing hot-melt ink A colorant and a binder agent containing a ketone resin and an ethylene-vinyl acetate copolymer resin as main components are dissolved or dispersed in a solvent. A three-roll mill is used for dispersion.

A commonly used dispersing machine such as a sentry mill, sand mill, or ball mill is used. This dissolved 1 dispersion liquid is used as an ink coating liquid.

(4) Coating and drying step of ink coating liquid The ink coating liquid is applied onto the film-like support 11 coated with the release layer 12 using the appropriate coating device.

Then, it is dried at 80-100'C. In this example, the coating thickness of the ink was set to 4 to 6 microns.

The manufacturing process of the thermal transfer ribbon 10 is thus completed, and the thermal transfer ribbon 10 as shown in FIG. 1 is obtained.

Examples of the thermal transfer ribbon according to the present invention are shown below as Example 1 and Example 2.

[Example 1] A, release layer a, release layer component... 1 part by weight polyethylene wax emulsion 92.5 wt% [Polyron #393 from Middle East Yushi Co., Ltd.] Bentonite
7.5wt% total 100wt% b. Diluent・・・・・・・・・1 part by weight water
100wt% B, heat-melting ink layer C, ink components...1 part by weight Ketone resin 55wt% [Maeyo Kagaku Kogyo (
Ethylene-vinyl acetate copolymer resin 25 wt% [Mitsui
DuPont Polychemical Co., Ltd.'s Evaflex 250] Polyvinyl butyral 5 wt% [Tsukumizu Kagaku Kogyo Co., Ltd.'s Esletsu M-81 Carbon black 15 wt% [Mitsubishi Chemical Industries, Ltd.'s MA-71 Total 100 wt% d. ......3 parts by weight Methyl isobutyl ketone 100 wt% Diluted with the above ingredients a to obtain a coating liquid. This coating liquid was coated to a thickness of 1 μm on a support 11 made of a 3.5 μm polyester film.
The peeling layer 1 is applied on the support 11.
Get 2.

-10= An ink coating liquid consisting of component C and component d is applied onto this release layer 12 and dried at 80 to 100'C. and,
A heat-melting ink layer 13 having a thickness of about 4 to 6 μm is formed on the peeling layer 12 on the support 11 .

When the thermal transfer ribbon 10 manufactured in this way was used to print on printing paper with a Beck smoothness of 4 seconds, the ink was transferred even to the concave parts of the printing paper, and there was very little fading and the eyes were sharp. A dark printed image was obtained.

Here, based on FIG. 2, a description will be given of the process of transferring heat-melting ink when printing is performed on printing paper with low smoothness using the thermal transfer ribbon 10 according to the present invention.

A thermal head 15 presses the thermal transfer ribbon 10 against a printing paper 16 on a pull-an (not shown). and,
When the thermal head 15 generates heat, the heat is conducted to the release layer 12 and the heat-melting ink layer 13 through the anti-sticking layer 14 and the σ film-like support 11, and the release layer 12
and the heat-melting ink layer 3 is melted, and the heat-melting ink that is in contact with the convex portions of the printing paper 16 is attached to the convex portions@(
Partial penetration). Then, when the thermal head 15 stops generating heat, the heat-melting ink layer 13 is cooled and fixed to the printing paper 16. At this time, the heated part of the peeled aSl1 layer 12 still maintains a liquid state, and the heat-melting ink layer 13 corresponding to this part has a strong cohesive force inside, but compared to the 1st layer. The adhesive force between the heat-melting ink layer 13 and the peeling layer 12 is extremely poor (the adhesive force between the heat-melting ink layer 13 and the peeling layer 12 in the non-heated portion is significantly smaller).

Therefore, the heat-melting ink layer 13 in the heated portion, that is, the printed image portion, is easily transferred to the printing paper 16 side, including the portions (concavities) that are not in contact with the printing paper 16, as shown in FIG. , At this time, the following relationship holds.

F4 >, Fl > F2 > F3 F1: Adhesive force of the heat-fusible ink layer 13 to the printing paper [2: Agglomeration of the heat-fusible ink layer 13 at the boundary between the heated part and the non-heated part] J F3: Heat-melted The adhesion force between the adhesive ink layer 13 and the release layer 11 or the adhesion force between the release layer 12 and the support 11 F4: Cohesive force of the heat-melting ink layer 13 in the heated portion In this way, this thermal transfer ribbon 10 The smoothness can be improved by utilizing the cohesive force of the heat-melt ink itself and by taking advantage of the low melt viscosity of the polyethylene wax emulsion of peeled t4tEi12 and its poor affinity with the heat-melt ink. High-quality printing without blurring is possible even on low-quality printing paper.

In addition, the fact that the fine molecules of the ethylene-vinyl acetate copolymer resin are not compatible with each other and are scattered within the ketone resin contributes to the sharpness of the heat-melting ink layer that is applied to the boundary between the heated and non-heated areas. In other words, it is thought that it contributes to the sharpness of printed characters.

[Example 2] A, Peeling layer a, Peeling layer component 1 part by weight, 100 wt% polyethylene wax emulsion [Polyron A manufactured by Middle East Yushi Co., Ltd.] b, Diluent...・・・・・・1 part by weight/water
100wt% B, heat-melting ink layer C, ink components...3 base part, ketone resin 50wt% [Ketone resin from Buyou Kagaku Kogyo Co., Ltd.] - ethylene-acetic acid Vinyl copolymer resin 30wt% [Evaflex 210 from Mitsui DuPont Polychemical Co., Ltd.
Carbon black 20wt% [Mitsubishi Kasei Corporation's MA-71 it 100wt% d, Solvent 7 parts by weight Methyl isobutyl ketone 100wt% Each of the above components When printing was performed using the thermal transfer ribbon 10 manufactured in the same process as in Example 1, the same printing quality as in Example 1 could be obtained.

Next, in order to compare with the thermal transfer ribbon according to the present invention, typical thermal transfer ribbons made of other components were prepared as Comparative Example 1. Comparative example 2. and Comparative Example 3.

Note that these Examples differ only in the components of the heat-fusible ink layer, and the components of the release layer of one layer of the peeler are common and are as described below.

[Common components] A, release layer a, release layer component 1 part by weight, polyethylene wax emulsion 100wt% [ME-10 from Chugoku Yushi Co., Ltd.] [Comparative example 1] B, heat-melting ink layer C, ink Ingredients: 1 part by weight Hydrogenated rosin 40 wt% [Hypere from Maeyo Kagaku Kogyo Co., Ltd.] Edylene-vinyl acetate copolymer resin 40 wt% [Evaflex J44 from Mitsui DuPont Polychemical Co., Ltd.]
1-2-1] - Carbon black 20wt% [MA-100 from Mitsubishi Chemical Industries, Ltd.] Total 10wt% d, Solvent 4 parts by weight - Toluene 100wt% Using the thermal transfer ribbon of Comparative Example 1, Beck smoothness was 4 When printing on second printing paper, the transfer to the concave portions of the printing paper was insufficient, and there were noticeable force scratches.

[Comparative Example 2] B, heat-melting ink layer C, ink component 1 part by weight - Ethylene-vinyl acetate copolymer resin 80 wt% [Mitsui DuPont Polychemical Co., Ltd. Evaflex 410] - Carbon black 20 wt% [Mitsubishi MA-100 manufactured by Kasei Kogyo Co., Ltd.] total of 100 wt% d, 4 parts by weight of solvent, 100 wt% of toluene The printing condition was slightly better than that of Comparative Example 1, and force scratches still occurred.

U Comparative Example 3] B, Heat-melting ink layer C, Ink component 1 part by weight Ketone resin 40 wt% [190% in ketone resin from Maeyo Kagaku Kogyo Co., Ltd.] Polyamide 40 wt% [Sanso Kagaku Kogyo Co., Ltd.] Sanmide #615A] ・Carbon black 20wt% [Mitsubishi Chemical Industries, Ltd. MA-100] Total 100wt% The layer is brittle and may peel off from the film-like support even if you rub it with your fingers, even without applying heat.

[Effects of the Invention] As detailed above, in the thermal transfer ribbon according to the present invention, a release layer is interposed between the film-like support and the heat-melt ink layer, and the heat-melt ink layer is made of ketone. It is formed using a heat-melting ink made by mixing a coloring agent and a binder agent mainly composed of resin and ethylene-vinyl acetate copolymer resin. During printing, when the thermal transfer ribbon is peeled off, it is peeled off from the support. Because the cohesive force of the heat-melt ink itself is greater than the adhesion between the layer or release layer and the heat-melt ink, the heat-melt ink in the non-contact areas corresponding to the recesses of the paper is It can be peeled off and transferred at the same time, making it possible to print clearly even on printing paper with low smoothness without force scratches or omissions.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view of a thermal transfer ribbon showing an embodiment of the present invention, FIG. 2 is a cross-sectional view showing the state of transfer onto printing paper by the thermal transfer ribbon, and FIG. 3 is a cross-sectional view of the printing paper and thermal transfer ribbon after printing. FIG. 10: thermal transfer ribbon, 11: support, 12: release layer, 1
3: Heat-melting ink layer

Claims (1)

[Claims] 1. A heat-melting ink formed by mixing a film-like support and a coloring agent and a binder agent whose main components are a ketone resin and an ethylene-vinyl acetate copolymer resin. A thermal transfer ribbon comprising: a meltable ink layer; and a release layer interposed between the support and the heat-meltable ink layer. 2. The thermal transfer ribbon according to claim 1, wherein the release layer mainly contains a wax having a low melt viscosity and poor affinity with the heat-melting ink.