JPS6337989A - Thermal transfer ribbon - Google Patents

Abstract

PURPOSE:To enable an easy erase and correction of an error printing with use of the same ribbon as well as a high-quality printing to a low-smoothness paper, by using a hot melt ink consisting of a specific reinforced film-forming resin and a specific tackiness producing resin. CONSTITUTION:A good printing can be obtained even on a low-smoothness paper by adding two or more kinds of water-soluble resins or water-dispersible resins to a thermal transfer ink layer 13 of a thermal transfer ribbon 10. The thermal transfer ink layer 13 is constructed as follows: a coloring agent is dispersed in a film-forming resin 15, having a high viscosity, a 200kg/cm<2> or more anti-tension, a 50% or more glass transition point, and a 200% or less extensibility, to prevent the penetration into a paper and the adhesion of the residual ink in erasing; on the other hand, a tackiness producing resin 16, having a 60-120 deg.C softening point, a 10<2>-10<4>P (150 deg.C) melt viscosity, a 200kg/cm<2> or less tensile strength a 0 deg.C or lower glass transition point, a 300% or more extensibility, a tackiness at a temperature of 80 deg.C or higher is dispersed to improve transfer properties and impart a required tackiness. The resin 15 and the resin 16 are incompatible with each other. In this manner, an error printing can be easily erased with a single ribbon that is used for printing.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a thermal transfer ribbon used in a thermal transfer printing device, and in particular, by using the same thermal transfer ribbon, once printed characters can be erased and plain paper (with low smoothness) can be used. low paper)
The present invention relates to a thermal transfer ribbon that can be printed on.

[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 predetermined heating element among the many heating elements of the thermal head to generate heat, the thermal transfer ribbon is applied to the heating element. This is done by melting the heat-melting ink portion that is in contact with the support via the support and transferring it to the printing paper.

Conventionally, this type of thermal transfer ribbon has simply been coated on a support with a heat-melting ink consisting of a colorant and a binder, and the binder has wax as its main component. Conventional thermal transfer ink is a type of ink that soaks into the paper, and one way to correct printing by mistake using this thermal transfer ink is to put white ink specifically for correction on top and erase it. (Unexamined Japanese Patent Publication No. 1983)
-74188, etc.). This takes time and effort, and in some cases, the area on which the white ink is applied becomes uneven, making it impossible to reprint. Moreover, the color of the correction area changes, making it unsightly.

Furthermore, when printing on paper with low smoothness using this conventional thermal transfer ribbon, sufficient print quality could not be obtained. This is thought to be because the heat-melting ink does not come into contact with the concave portions of the paper, resulting in poor transfer and causing casts, scratches, etc. To prevent this, increase the presser pressure of the thermal head,
Possible solutions include increasing the coating thickness of hot-melt ink. However, when the presser foot pressure is increased, the amount of ink that gets onto the convex parts of the paper decreases, and it collects in the concave parts, resulting in uneven print density, blurred or whitish prints, and the thermal head wears out quickly. There may also be problems such as damage to the support of the hot-melt ink. Also,
Increasing the coating thickness of the heat-melting ink causes a problem in that the print area expands, the lines become thicker, and the characters lack sharpness and definition. Furthermore, as shown in Japanese Patent Application Laid-Open No. 57-22090, after coating a heat-melting ink on a base material, a thin polymer layer is formed on the ink layer to prevent penetration, and printing is carried out. To prevent the thermal transfer ink from penetrating the printed paper and erase the printed image, there are methods to lightly rub it with an eraser or peel off the printed image with adhesive tape, but the revised area may be noticeable. Furthermore, the ribbon production is complicated because the number of coating steps is increased. Moreover, it cannot be erased with the same ribbon. Furthermore, JP-A-58-74368 discloses a peel-off type modification using a thermoplastic material that is non-tacky at normal temperatures but becomes sticky at elevated temperatures below the melting point of the ink to be peeled off. ing. This material can be a ``single material or a mixture,'' and specifically, it can be ``a mixture of a thermoplastic resin such as polyamide and a compatible usually high viscosity material such as rubber or rosin,'' or ``a mixture of low softening and "It consists of a mixture of two similar thermoplastic materials with intermediate softening points."

However, the invention of JP-A-58-74368 provides an ink ribbon for an electrical transfer printing device, and when applied to a thermal transfer printing device with low thermal efficiency and significantly different conditions, it is different from the conventional one. It is thought that a considerably large amount of thermal energy is required in comparison, and therefore it is not suitable for thermal transfer printing devices. Furthermore, the material used for the heat-melting ink of the present invention is a mixture of mutually incompatible resins A and B, which have different properties, and the characteristics of these resins are also disclosed in JP-A-58-74368@. There is a big difference between a "single material" and a "mixture."

[Object of the Invention] This invention has been made in view of the above-mentioned problems in the prior art, and its first purpose is to prevent the occurrence of the same problem when printing by mistake with a printing device such as a thermal transfer typewriter or printer. It can be easily erased using a ribbon without any hassle.
Another object of the present invention is to provide a thermal transfer ribbon that allows printed characters to be corrected by reprinting thereon.

A second object of the present invention is to provide a thermal transfer ribbon capable of obtaining sufficiently good print quality without casters, marks, etc. even on paper with low smoothness.

Furthermore, a third object of the present invention is to improve the working environment in the manufacturing process by using a resin using water as a solvent, and to eliminate the effects of organic solvents on the human body.

[Embodiments] Examples 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 an ink layer 13 further formed thereon. The film-like support 11 used in this example is a film made of polyester, polyimide, polycarbonate, polysallefone, polyether-length sulfon, polyphenylene sulfide, etc., which has a heat resistance temperature of 150° C. or higher, or capacitor paper,
Examples include plasticine paper, and the thickness thereof is preferably in the range of 3 to 20 μm. Further, as shown in FIG. 1, an anti-sticking layer 18 made of a heat-resistant resin such as silicone resin is provided on the surface of the support 11 opposite to the surface coated with the ink layer 13.

The ink layer 13 includes a colorant 14, a sclera-forming resin 15,
It is composed of tackifying resin 16.

As the colorant 14, a pigment such as carbon black is mainly used. Further, a dye may be added as necessary to adjust the color tone.

In addition, the sclera-forming resin 15 has an extremely high viscosity or a viscosity that hardly flows even when softened, and has a tensile strength of 2.
00Kl/ci or more, glass transition point 50℃ or more, elongation rate (percentage of difference between the length of the sample when stretched and the original length, relative to the original length) 200% or less, and colorant 14 and One type or a mixture of two or more types of water-soluble resins having good affinity for, for example, polyvinylpyrrolidone, polyvinyl alcohol, polyethylene oxide, hydroxyethylcellulose, hydroxypropylcellulose, methylcellulose, and carboxymethylcellulose are used.

The tackifier resin 16 is incompatible with the sclera-forming resin 15, has a softening point of 60 to 120°C, and a melt viscosity of 102 to 1.
04P (Poise) (150℃), tensile strength 200 to 9/C
One type or a mixture of two or more types of water-dispersible resins having a glass transition point of 0° C. or lower, an elongation rate of 300% or higher, and exhibiting tackiness at at least 80° C. or higher are used. For example, emulsions such as acrylic, acrylic ester, acrylic-styrene copolymer, ethylene-vinyl acetate, ethylene-vinyl chloride-vinyl acetate, and vinyl acetate are used.

Note that if the colorant 14 is poorly dispersed, a dispersant such as a nonionic surfactant may be used as necessary.

Furthermore, the release layer 12 is provided between the support 11 and the ink layer 13 so that the ink layer 13, which has strong adhesiveness to the support 11, can be sufficiently transferred to the paper by the heat generated by the thermal head 20. The release layer 12 is made of wax, such as polyethylene wax, which has a melting point of 80 to 120°C and has poor adhesion to the support 11. During printing, the release layer 12 becomes completely molten and the ink layer 13 easily separates from the support 11. During peeling and erasing, which is at a lower temperature than during printing, the ink becomes solidified and has the effect of strongly binding the support 11 and the ink layer 13. The release layer 12 may be made of a single substance such as polyethylene wax, but other waxes or fillers such as bentonite, kaolin, talc, etc. may be added thereto, thereby changing the transferability in a favorable direction. can.

In FIG. 2, the sclera-forming resin 17 is substituted for the sclera-forming resin 15 in FIG.
Emulsions such as vinyl chloride, ethylene-vinyl chloride-vinyl acetate, water-soluble polyester, and water-soluble polyamide, and latexes such as SBR and NBR are used alone or in combination. By using these dispersions and adjusting the drying temperature, it is possible to increase the film strength to an appropriate level and improve transferability.

In FIG. 3, the penetration prevention layer 19 is provided on the ink layer 13 of FIGS. 1 and 2.

Although erasability and transferability are sufficiently good even without this permeation prevention layer 19, it may be provided to further ensure both.

The characteristics and structure of the thermal transfer ribbon 10 shown in FIGS. 1 to 3 will be summarized below.

The thermal transfer ink layer 13 is made with appropriate softening point, cohesive force, film forming property, and melt viscosity by adding two or more types of water-soluble resins or water-dispersible resins, and is suitable for thermal transfer typewriters,
Good print quality can be obtained when printing with a printer, etc., and it can be clearly erased. At this time, the ink layer 13 can be coated even on paper with low smoothness. High viscosity of 200 KH/crA to obtain good printing without whitening, and to prevent penetration into paper and residual adhesion during erasing.
Tensile strength over 50%, glass transition point over 50%, elongation rate over 20
The coloring agent is dispersed in the sclera-forming resin 15.17, which has properties of 0% or less, and on the other hand, it eliminates the stringiness and poor cutting caused by the resin 15.17, improves the transferability, and also improves the To provide the necessary tackiness, a softening point of 60-120°C, a melt viscosity of 10-10 P (at 150°C), 20ON
Tensile strength below ff/rm, glass transition point below 0°C, 3
It has a structure in which a tackifying resin 16 having an elongation rate of 0.00% or more and tackiness at 80° C. or more is also dispersed. Here, the sclera-forming resin 15, 17 and the tackifier resin 16 are incompatible with each other.

By making the ink layer 13 formed in this way sticky at 80° C. or higher, it can be easily erased with the same ribbon used for printing, and its erasability is also good. Examples of the thermal transfer ribbon according to the present invention are shown below as Example 1 and Example 2.

(Example 1) A, I! ! I type! ! ! 1 part by weight, polyethylene wax emulsion 50 wt% [ME-101 from Middle East Yushi Co., Ltd., 50 wt% water B, heat-melting ink layer, polyvinyl alcohol 8 parts by weight [Gohsenol KH-20, Nippon Gosei Kagaku Kogyo Co., Ltd.] Ethylene-vinyl acetate copolymer 205 parts by weight [Mitsui Petrochemical Industries, Ltd. Chemipearl V-300] ・Carbon black 10 parts by weight [Mitsubishi Chemical Industries, Ltd. MA-100] ・Water 277 parts by weight 3 parts of the above A ．．
Support 1 made of 5 μm polyester film
1 to obtain a release layer 12 on the support 11 so that the dry coating thickness is approximately 1 μm. Ink coating liquid B is applied onto the release layer 12 and dried at 60 to 100°C. Then, on the release layer 12 on the support 11, a dry film thickness of 4 to 10μ is applied.
m ink layers 13 are formed.

The thermal transfer ribbon 10 manufactured in this way is equipped with a thermal head having a heat generating part on the end surface, and the pressing force of the thermal head is 300 to 600 C1f, and the peeling point (the thermal transfer ribbon is separated from the printing paper) from the heat generating part using a thermal printer with a distance of 100 to 300 μm to the point), a moving speed of the thermal head of about 40 m/s, and a surface temperature of the printing paper side of the thermal transfer ribbon raised by the heat generating part of 100 to 150 °C. Beck smoothness 3~
When printing was performed on paper for 4 seconds, 40-50 seconds, and 400 seconds, the ink was transferred to the concave portions of each paper (it did not penetrate), and there were no scratches or center marks, and the prints were sharp and dense. Good printing with a high level of color was obtained.

In addition, an auxiliary pinch roller is used to maintain contact between the thermal transfer ribbon and the printing paper, and the distance from the heat generating part to the peeling point is approximately 8 m+, that is, the time to separate the thermal transfer ribbon and the printing paper is delayed as appropriate. In this state, when the same ribbon was used to print the same character on the previously printed characters on each printing paper, the characters (ink) on the printing paper were reversely transferred to the thermal transfer ribbon side, and the printing paper The letters on the top were clearly peeled off and erased.

(Example 2) A, i! ! I-type layer 1 layer 1 part
Polyethylene wax emulsion 5Qwt% [Mideast Yushi Co., Ltd. ME-101 ・Water 5Qwt% B, heat-melting ink layer ・40 parts by weight of ethylene-vinyl chloride-vinyl acetate copolymer [Sumikaflex from Sumitomo Chemical Co., Ltd.]・Ethylene-
68 parts by weight of vinyl acetate copolymer [Mitsui Petrochemical Industries, Ltd.'s Chemipearl V/Cahone Black 10 parts by weight [Mitsubishi Chemical Industries, Ltd.]
A-1001・Anionic surfactant 2 layers [Demol N from Kao Corporation] ・Water 380 layers Printed using the thermal transfer ribbon 10 manufactured in the same manner as in Example 1 with each of the above components The same print quality and erasability as in Example 1 could be obtained.

In addition, the tensile strength of the sclera-forming resin component is 20ONf.
If it is less than f/cm or the glass transition point is less than 50° C., the crosslinking property will deteriorate, making it difficult to handle rough paper, and self-destruction etc. will easily occur. Furthermore, if the elongation rate exceeds 200%, stringiness tends to occur, and the printed surface becomes uneven.

On the other hand, the tackifying resin component has a melt viscosity of 102
If the temperature exceeds the range of 104P (150 DEG C.), the adhesiveness will be insufficient and both erasability and transferability will deteriorate.

Moreover, below this range, the adhesiveness becomes too strong and it becomes difficult to peel it off from the printing paper. Tensile strength is 200Kl/C17
If it exceeds 1, the tackiness will decrease and ink will remain on the printing paper during erasing, and if the glass transition point of the tackiness exceeds 0°C or the elongation rate is less than 300%, the tackiness will decrease. Peel-erasability deteriorates or becomes impossible.

[Effects of the Invention] As detailed above, the thermal transfer ribbon according to the present invention is formed of a film-like support, a sclera-forming resin A, a tackifier resin B, a release layer, and an anti-sticking layer. It is something.

The resin A provides sufficient cohesive force between the inks to enable transfer that corresponds to the unevenness of the paper when printing on printing paper with low smoothness. Further, by dispersing the colorant into the resin A, the colorant is prevented from penetrating into the printing paper and from being left behind during erasing. Further, the resin B is incompatible with the resin A, provides the necessary tackiness during erasing, and also
By adjusting the film strength of the ink layer to an appropriate level, it eliminates poor sharpness and stringiness and improves transferability.

The effects on transferability and erasability when such a hot-melt ink is used are as follows.

During printing, the release layer is in a molten state, so the agglomerated peaks of the heat-melt ink itself are larger than the adhesion between the support of the thermal transfer ribbon and the heat-melt ink, causing it to form in the recesses of the printing paper. The heat-melting ink in the corresponding non-contact area can also be transferred to the printing paper side, allowing clear printing without smudges or blemishes even on printing paper with low smoothness.

In addition, when erasing erroneous printing, the heat-melt ink on the support becomes sticky due to heat and is integrated with the transferred heat-melt ink, compared to the adhesive strength between the transferred heat-melt ink and the printing paper. The cohesive force of the ink itself is greater, and the release layer solidifies to strongly connect the support and the ink layer.
It is possible to remove the ink from the erroneously printed area from the paper to the thermal transfer ribbon side.

[Brief explanation of drawings]

FIG. 1 is a sectional view of a thermal transfer ribbon that is an embodiment of the present invention, and FIG. 2 is a sectional view of a thermal transfer ribbon that is another embodiment of the present invention.
FIG. 3 is a cross-sectional view of a thermal transfer ribbon provided with a penetration prevention layer. In the figure, 14 is a coloring agent, 15 and 17 are sclera-forming resins, and 1
6 is a tackifying resin.

Claims (1)

[Scope of Claims] A coloring agent having an extremely high viscosity or a viscosity that hardly flows even when softened, a tensile strength of 200 kg/cm^2 or more, a glass transition point of 50° C. or more, and an elongation rate of 200% or less. A sclera-forming resin consisting of a water-soluble resin or water-dispersible resin with good affinity, and a sclera-forming resin that is incompatible with this resin, has a softening point of 60 to 120℃, and a melt viscosity of 10^2 to 10^4P (150℃). , tensile strength 200Kg
/cm^2 or less, glass transition point 0℃ or less, elongation rate 300
% or more, a tackifying resin made of a water-dispersible resin exhibiting tackiness at least at 80° C. or higher, and a heat-melting ink made of the heat-melting ink.