JP2531143B2 - Thermal transfer ribbon - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a thermal transfer ribbon used in a thermal transfer printing apparatus, and in particular, by using the same thermal transfer ribbon, it is possible to erase a character once printed and to print on a plain paper (with smoothness The present invention relates to a thermal transfer ribbon capable of printing on low paper).

[Prior Art] When printing with a thermal transfer ribbon, the thermal transfer ribbon is brought into close contact with a printing paper by a thermal head, and a predetermined heating element among a large number of heating elements of the thermal head is caused to generate heat. This is performed by melting the heat-meltable ink portion in contact with the support and transferring the melted ink onto the printing paper.

Further, conventionally, this type of thermal transfer ribbon has only a hot-melt ink composed of a colorant and a binder agent coated on a support, and the binder agent has a wax as a main component. Such a conventional thermal transfer ink is a type of ink that is made to soak into paper, and one of the correction methods when printing is mistaken using this thermal transfer ink is to apply a white ink dedicated to the correction from above and erase it. (JP-A-57
-74188 publication). This takes time and labor, and in some cases, the portion on which the white ink is applied becomes uneven, and reprinting becomes impossible. In addition, the color of the correction part changes, which makes it unsightly.

Further, when printing was performed on a paper having low smoothness with this conventional thermal transfer ribbon, sufficient printing quality could not be obtained. It is considered that this is because the heat-melting ink does not come into contact with the concave portion of the paper, resulting in poor transfer and causing scratches, dropouts, and the like.
In order to prevent this, increasing the pressing pressure of the thermal head and increasing the coating thickness of the heat-meltable ink can be considered. However, if the presser foot pressure is increased, the amount of ink on the convex portion of the paper will decrease and the ink will collect in the concave portion, resulting in uneven print density, and there is a problem that the print becomes blurry or whitish, and the thermal head wears quickly. There are also obstacles such as deterioration and damage to the support of the hot-melt ink. Further, when the coating thickness of the heat-meltable ink is increased, the printing range is widened and the line becomes thicker, resulting in a character lacking in sharpness and sharpness. In addition, as shown in JP-A-57-22090, after coating a hot-melt ink on a substrate, a thin polymer layer for preventing penetration is further formed on the ink layer for printing. At this time, in order to prevent the thermal transfer ink from penetrating into the printing paper and erase the printed image, there are some cases where the printed image is lightly rubbed with an eraser or the adhesive tape is used to peel off the printed image. Ribbon production is complicated because the number of coating processes increases. Moreover, it cannot be erased with the same ribbon. Furthermore, JP-A-58
-74368 discloses a non-tacky ink at a normal temperature, but at an elevated temperature lower than the melting point of the ink to be peeled off,
Peelable modification with tacky thermoplastic materials is mentioned. This material is "single material or mixture"
And specifically "a mixture of a thermoplastic resin such as polyamide and a compatible, usually viscous material such as rubber rosin" or "two similar heats with low and intermediate softening points. It consists of a mixture of plastic materials. "

However, the invention of Japanese Patent Application Laid-Open No. 58-74368 provides an ink ribbon for an electric current transfer printing apparatus, and when applied to a thermal transfer printing apparatus having low thermal efficiency and greatly different under other conditions, It is considered that it requires a considerably large amount of heat energy, and was not suitable for a thermal transfer printer. Further, the materials used for the heat-meltable ink of the present invention are mutually incompatible resins A having different properties,
In addition to being a mixture of resin B, the properties of these resins are also known.
"Mixed material" and "single material" disclosed in Japanese Patent Publication No. 58-74368
Is very different.

[Object of the Invention] The present invention has been made in view of the above-mentioned problems of the prior art. The first object of the present invention is to provide the same ribbon when a printing device such as a thermal transfer typewriter or printer erroneously prints. It is possible to provide a thermal transfer ribbon which can be easily erased without any trouble by using, and which can be printed again to correct printed characters. A second object of the present invention is to provide a thermal transfer ribbon capable of obtaining a sufficiently good printing quality with no blurring or omission even on paper having low smoothness. Furthermore,
A third object of the present invention is to improve the working environment in the manufacturing process by using a resin having water as a solvent and to eliminate the influence of the organic solvent on the human body.

[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-shaped support 11 and an ink layer formed on the release layer 12.
13 is formed. As the film-shaped support 11 used in this example, a heat-resistant temperature of 150 ° C. or higher polyester, polyimide, polycarbonate, polysulfone,
Examples thereof include films made of polyether sulfone, polyphenylene sulfide, etc., condenser paper, brushon paper and the like, and the thickness thereof is preferably in the range of 3 to 20 μm. Further, as shown in FIG. 1, a sticking prevention layer 18 made of a heat resistant resin such as silicone resin is provided on the surface of the support 11 opposite to the coated surface of the ink layer 13.

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

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

Further, the sclera forming resin 15 has an extremely high viscosity or a viscosity such that it hardly flows even when softened, and has a tensile strength of 20%.
0 kg / cm ² or more, glass transition temperature 50 ° C. or more, elongation (percentage of difference between sample length when stretched and original length relative to original length) 200% or less, colorant 14 A water-soluble resin having a good affinity with, for example, polyvinylpyrrolidone, polyvinyl alcohol, polyethylene oxide,
One or more of hydroxyethyl cellulose, hydroxypropyl cellulose, methyl cellulose and carboxymethyl cellulose are mixed and used.

The tackifying resin 16 is incompatible with the scleral-forming resin 15 and has a softening point of 60 to 120 ° C., a melt viscosity of 10 ² to 10 ⁴ P (poise) (150 ° C.), a tensile strength of 200 kg / cm ² or less, Glass transition point 0
One or two or more water-dispersible resins which have an elongation of 300 ° C. or less and an adhesiveness of at least 80 ° C. or more are used together. For example, it is an emulsion of acrylic, acrylic ester, acrylic-styrene copolymer, ethylene-vinyl acetate, ethylene-vinyl chloride-vinyl acetate, vinyl acetate and the like.

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

In addition, the release layer 12 is an ink layer having strong adhesion to the support 11.
It is provided between the support 11 and the ink layer 13 so that 13 can be sufficiently transferred to the paper by the heat of the thermal head 20.
The release layer 12 is composed of a wax having a melting point of 80 to 120 ° C. and poor adhesion to the support 11, such as polyethylene wax, and is in a completely molten state during printing, and the ink layer 13 easily separates from the support 11. When the peeling and erasing are performed at a temperature lower than that at the time of printing, the support 11 is solidified.
Has a function of strongly connecting the ink layer 13 with the ink layer 13. The release layer
The polyethylene 12 may be a single substance such as polyethylene wax, but other wax may be added or a filler such as bentonite, kaolin or talc may be added, whereby the transferability can be changed in a preferable direction.

In FIG. 2, the sclera-forming resin 17 is a dispersion aqueous solution of a resin having the properties of the resin 15 instead of the sclera-forming resin 15 in FIG. 1, such as acrylic, ethylene-vinyl chloride, ethylene-vinyl chloride. -Emulsion of vinyl acetate, water-soluble polyester, water-soluble polyamide, or SB
One or more of latexes such as R and NBR are mixed and used. By using these dispersions and adjusting the drying temperature, it is possible to make the film strength moderate and improve the transferability.

In FIG. 3, the permeation preventive layer 19 is provided on the ink layer 13 of FIGS. 1 and 2. This permeation prevention layer 19
Although the erasing property and the transfer property are sufficiently good even without the presence of the above, it may be provided in order to further secure the both.

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

The thermal transfer ink layer 13 has a softening point, cohesive force, film forming property, and melt viscosity that are adjusted to appropriate values by adding two or more water-soluble resins or water-dispersible resins, for printing with a thermal transfer typewriter, printer, or the like. It is possible to obtain good print quality and erase the image clearly.
At that time, the ink layer 13 can obtain good printing without blurring and white spots even on paper with low smoothness, high viscosity to prevent penetration into paper and residual adhesion during erasing, and tensile strength of 200 kg / cm ² or more. , A colorant is dispersed in the scleral-forming resin 15, 17 having a glass transition point of 50% or more and an elongation rate of 200% or less,
On the other hand, eliminating the stringiness and poor cutting of the resin 15,17,
In order to improve transferability and to give necessary adhesiveness at the time of erasing, softening point of 60 to 120 ° C, melt viscosity of 10 ² to 10 ⁴ P (150 ° C), tensile strength of 200 kg / cm ² or less, 0 ° C It has a structure in which the tackifying resin 16 having the following glass transition point, elongation of 300% or more, and tackiness at 80 ° C. or more is also dispersed. Here, the sclera forming resins 15 and 17 and the tackifying resin 16 are incompatible with each other.

The ink layer 13 thus formed can be easily erased with the same ribbon as that for printing by giving it an adhesive property at 80 ° C. or more, and the erasability thereof is excellent. 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 1 part by weight-Polyethylene wax emulsion 50 wt% [ME-10 of Chukyo Yushi Co., Ltd.]-Water 50 wt% B. Hot-melt ink layer-Polyvinyl alcohol 8 parts by weight [Nippon Gosei Co., Ltd.] Chemical Industry Co., Ltd. Gohsenol KH-20] -Ethylene-vinyl acetate copolymer 205 parts by weight [Mitsui Petrochemical Industry Co., Ltd. Chemipearl V-300] -Carbon black 10 parts by weight [Mitsubishi Chemical Industry Co., Ltd. MA-100 Water 277 parts by weight The above A is coated on a support 11 formed of a 3.5 μm polyester film so that the dry coating film thickness is about 1 μm, and a release layer 12 is obtained on the support 11. The ink coating liquid B is applied onto the release layer 12 and dried at 60 to 100 ° C. Then, an ink layer 13 having a dry film thickness of 4 to 10 μm is formed on the release layer 12 on the support 11.

Using the thermal transfer ribbon 10 manufactured in this manner, a thermal head having a heat generating portion on the end face is provided, the pressing force of the thermal head is 300 to 600 gf, and the peeling point from the heat generating portion (the thermal transfer ribbon is separated from the printing paper. Distance)
100-300μm, the moving speed of the thermal head is about 40mm / s,
Using a thermal printer whose surface temperature on the printing paper side of the thermal transfer ribbon raised by the heat generating part is 100 to 150 ° C, prints on printing paper with Beck smoothness of 3 to 4 seconds, 40 to 50 seconds, and 400 seconds, respectively. As a result, the ink was transferred (not permeated) to the recesses of any of the printing papers, and there was no blurring or omission, and sharp, high-density good printing was obtained.

In addition, the contact between the thermal transfer ribbon and the printing paper is maintained by using an auxiliary pinch roller, and the distance from the heat generating part to the peeling point is set to about 8 mm, that is, the time for separating the thermal transfer ribbon and the printing paper is appropriately delayed. In this state, when the same character is printed using the same ribbon on the character previously printed on each printing paper, the character (ink) on the printing paper is reverse-transferred to the thermal transfer ribbon side, The above letters were vividly peeled and erased.

(Example 2) A. Release layer 1 part by weight-Polyethylene wax emulsion 50 wt% [ME-10, Chukyo Yushi Co., Ltd.]-Water 50 wt% B. Hot-melt ink layer-Ethylene-vinyl chloride-vinyl acetate-co Polymer 40 parts by weight [Sumikaflex 850 from Sumitomo Chemical Co., Ltd.]-Ethylene-vinyl acetate copolymer 68 parts by weight [Memii Petrochemical Co., Ltd. Chemipearl V-100] -Carbon black 10 parts by weight [Mitsubishi Chemical Industry MA-100] -Anionic surfactant 2 parts by weight [Kao Corporation's Demol N] -Water 380 parts by weight Thermal transfer ribbon 10 produced in the same manner as in Example 1 with the above components. When printing was carried out using, it was possible to obtain the same print quality and erasability as in Example 1 above.

The scleral-forming resin component has a tensile strength of 200 kg / cm.
^If it is less than ² or the glass transition point is less than 50 ° C., the crosslinkability is deteriorated, the compatibility with rough paper is deteriorated, and white spots are likely to occur. On the other hand, if the elongation exceeds 200%, stringing is likely to occur and the printed surface becomes uneven.

On the other hand, in the tackifying resin component, the melt viscosity is 10 ²
If it exceeds the range of up to 10 ⁴ P (150 ° C), the tackiness is insufficient and the erasability and transferability are deteriorated. On the other hand, if it is less than this range, the adhesiveness becomes too strong, and it becomes difficult to peel it from the printing paper.
If the tensile strength exceeds 200 kg / cm ² , the adhesiveness will decrease and the ink will remain on the printing paper during erasing. Also, if the glass transition point is such that the adhesiveness exceeds 0 ° C or the elongation is less than 300%, the adhesiveness will increase. As a result, the peelability and erasability deteriorate or become impossible.

[Effects of the Invention] As described in detail above, the thermal transfer ribbon according to the present invention has a film-shaped support, a scleral-forming resin A, and a tackifying resin B.
And a release layer and a sticking prevention layer.

The resin A provides sufficient cohesive force between inks in order to enable transfer corresponding to the unevenness of the paper when printing on printing paper having low smoothness. Further, by dispersing the colorant in the resin A, the colorant is prevented from permeating the printing paper and remaining adhered during erasing. In addition, the resin B is incompatible with the resin A and gives the necessary tackiness at the time of erasing. Further, the film strength of the ink layer by the resin A is set to an appropriate level to eliminate the poor breaking and the stringing. Improve transferability.

The effects on transferability and erasability when using such a heat-meltable ink are as follows.

During printing, since the release layer is in a molten state, the cohesive force of the heat-meltable ink itself is larger than the adhesive force between the support of the thermal transfer ribbon and the heat-meltable ink. Corresponding non-contact portion of the heat-melting ink can also be transferred to the printing paper side, and clear printing can be performed on printing paper with low smoothness without blurring or missing.
Further, when erroneous printing is erased, the heat-meltable ink on the support is integrated with the heat-meltable ink that has the adhesiveness due to heat as compared with the adhesive force between the heat-meltable ink transferred and the printing paper. The cohesive force of itself is greater, and because the release layer solidifies and strongly connects the support and the ink layer,
It is possible to peel off the ink on the misprinted portion from the paper to the thermal transfer ribbon side sufficiently and cleanly.

[Brief description of drawings]

FIG. 1 is a sectional view of a thermal transfer ribbon which is an embodiment of the present invention, FIG. 2 is a sectional view of a thermal transfer ribbon which is another embodiment, and FIG. 3 is a sectional view of a thermal transfer ribbon provided with a penetration preventing layer. Is. In the figure, 14 is a colorant, 15 and 17 are scleral forming resins, and 16 is a tackifying resin.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Hatsue Ohno 9-35 Hotta-dori, Mizuho-ku, Nagoya-shi Yoshio Sugano, Examiner, Brother Industries, Ltd. (56) Reference JP-A-57-22090 (JP, A) JP-A-57-74188 (JP, A) JP-A-58-74368 (JP, A) JP-A-61-54984 (JP, A) JP-A-61-137788 (JP, A) International Publication 86/4859 ( (WO, A)

Claims (1)

(57) [Claims] 1. A colorant having an extremely high viscosity or a viscosity such that it hardly flows even when softened, a tensile strength of 200 kg / cm ² or more, a glass transition point of 50 ° C. or more, an elongation of 200% or less, and an affinity with the colorant. and sclera forming resin consisting of sex good water-soluble resin or water dispersible resin, the resin incompatible, softening point 60 to 120 ° C., a melt viscosity between 10 ² and
A tackifying resin comprising a water-dispersible resin having a viscosity of 10 ⁴ P (150 ° C.), a tensile strength of 200 kg / cm ² or less, a glass transition point of 0 ° C. or less, an elongation of 300% or more, and at least 80 ° C. or more;
Transfer ribbon having a heat-meltable ink comprising the following.