JPH0262290A - Thermal transfer recording medium - Google Patents

Abstract

PURPOSE:To eliminate a shortcoming that a shade of a character occurs when printing is repeated, by a method wherein an intermediate adhesive layer formed of hot-melt ink and heat-resistant resin is interposed between a support and a hot-melt ink layer. CONSTITUTION:A hot-melt ink layer 1 is laminated on a support 3 with an adhesive layer 2 formed of hot-melt ink 2a and heat-resistant resin 2b interposed therebetween. When printing is repeated, the hot-melt ink 2a in the adhesive layer 2 is also transferred sequentially and thereby a print of high density is obtained. The weight ratio between the hot-melt ink and the heat-resistant resin is suitably 5:95 to 90:10.

Description

[Detailed description of the invention]

[Industrial Application Field] The present invention relates to a recording medium related to a thermal transfer recording method used in word processors, computer printers, and the like. More particularly, the present invention relates to a thermal transfer recording medium that can produce high-density prints many times and that reduces the decrease in print density with the number of times it is used. [Prior Art] As a thermal transfer recording medium intended to enable multiple printing, a resin layer having fine pores is formed on a support, and heat-melting ink is injected into the fine pores. The heat-melting ink in the fine pores is gradually transferred to the recording paper each time by heating with a thermal head, etc., and the technology of the thermal transfer recording medium is capable of being used many times. It has also been proposed that support L contains fine powder in hot-melt ink, and the fine powder makes the ink layer look like a stone wall, thereby suppressing the amount of ink transferred at one time by heating with a thermal head, etc. , multiple use ++ J-capable heat-sensitive transfer ++, I note t,
A medium technology has also been proposed. [Problems to be solved by the invention] Conventional techniques as described above have been proposed, but in the former technique, the microporous structure is not sufficiently uniform and lacks continuity.
The amount of ink seeping out was small and only low-density prints were obtained, so the number of prints was reduced to 1 (

[The drawback is that the density of the print immediately decreases when it is wet. Moreover, in the latter technique, the cohesive force of the fine powders is high, and the voids between them are small. Therefore, sufficient density cannot be obtained for 51 printings due to a decrease in the amount of retained heat-melting ink, and there is a drawback 2 that the characters become darker and darker as soon as the number of printings is increased. The present invention aims to eliminate the following drawbacks. [Means for Solving the Problems] In order to solve the problems as described in +'+ji, the present invention provides the following:
A heat-fusible ink and a heat-resistant resin are placed between the support and the hot-fusible ink layer. It has a structure in which an intermediate adhesive layer is interposed. [Structure of the Invention] Hereinafter, the present invention will be described in further detail. FIG. 1 is a sectional view showing the structure of a thermal transfer recording medium according to the present invention. A support (3) is coated with an adhesive layer (2) consisting of a heat-melting ink (2a) that is 1M-shaped at room temperature and becomes liquid when heated, and a heat-resistant resin (2b), and an adhesive layer (2) that is solid at room temperature and becomes liquid when heated. When the back side of the 6 support (3) coated with the heat-fusible ink layer (1) is partially heated by a thermal head, the heat-fusible ink in that area becomes liquid and is used to print on recording paper, etc. Although printing is performed on the object to be transferred, all of the heat-fusible ink in the heated portion does not occur due to the adhesive force of the adhesive layer (2), and
As the number of printing increases, the heat-melting ink (2d) in the adhesive layer (2) is sequentially transferred together with the ink in the heat-melting ink layer (1). Therefore, high-density printing can be obtained many times, and the decrease in 1F character density due to the number of uses is small.
5. The heat used to form the heat-melting ink layer according to the present invention, which makes it possible to obtain high-quality printing. 8. Fusible ink, solid wax, heat iiJ! It consists of IIIJ resins and oils, and is heated to I81.7 with three rolls or the like. The limbs can be easily adjusted. The coloring agents include - numerically used organic pigments such as copper phthalocyanine and lake red; inorganic pigments such as carbon black navy blue and 7; and urea-soluble organic acid salts of basic dyes such as nigrosine base and methibibase. Examples include dyes and the like. Also, i
Examples of the waxes described in q include solid waxes having a melting point of 50 to 120°C, such as montan wax, carnauba wax, candelilla wax, microcrystalline wax, polyethylene wax, wood wax, beeswax, and lanolin. Examples of thermoplastic resins include ethylene-vinyl acetate co-R combination, vinyl acetate resin, rosin resin, acrylic resin, and phenol resin. Note that 1. When a pigment is used as a coloring agent, a suitable dispersant may be used in combination. 1. Heat-resistant resins constituting the adhesive layer according to the present invention include fiber cord resins such as methylcellulose, ethylcellulose, and cellulose acetate. , vinyl acetate, polyvinyl alcohol, polyvinyl acetal, vinyl chloride-vinyl acetate copolymer, vinyl resins such as vinylidene chloride, other acrylic acid resins, polyester resins, polyamide resins, etc., with a softening point of 100°C or higher, preferably Examples of the resin include heat-resistant resins of 120° C. or higher. Further, the heat-melting ink constituting this adhesive layer can be arbitrarily selected from the colorants, solid waxes, thermoplastic resins, and oils forming the heat-melting ink layer, and adjusted. be done. The weight ratio of the heat-melting ink and the heat-resistant resin constituting the adhesive layer is 5:95 to 90:10, preferably 10:90 to 70:30. If the proportion of the hot-melt ink is less than 5%, printing of sufficient density cannot be obtained due to the heating of the thermal head, etc., and the printing density decreases significantly with the number of times of use. Moreover, if it is 90 or more -1-, the adhesive force as an adhesive layer will not be effective, and all the heat-melting ink will be transferred at once by heating with a thermal head etc., making it impossible to use it many times. As the support according to the present invention, conventionally known polyethylene terephthalate, polycarbonate,
Examples include heat-resistant films such as polyimide, and thin papers such as condenser paper and glassine paper. Further, the thickness thereof is preferably 2.5 to 10 μm. or,
On the surface heated by a thermal head etc. as necessary,
The above-mentioned hot-melt ink layer and adhesive layer, which may be provided with a heat-resistant protective layer made of silicone resin, fluororesin, polyimide resin, etc., can be formed by conventionally known hot-melt coating,
0.1 each by methods such as solvent coating.
Laminated coating is applied to a thickness of μ to 10 μ. [Examples] Examples will be given below in order to describe the present invention in more detail. Note that the embodiments of the present invention are not limited to these. Example 1 (Parts by weight) Ink A Carbon black carnauba wax Microcrystalline wax Ink Δl O! fully dispersed with IMI using a liquid paraffin meter hot copy roll. lr'+< parts and ethyl cellulose 20
(: Put the ridge and 70 parts of toluene into an attritor and grind and disperse for 2 hours to prepare the ink that will become the adhesive layer. Solvent coat the ink on a 3.5μ thick polyethylene terephthalate film and dry. Back J+
An adhesive layer with a diameter of 5 μm was obtained. Next, a heat-melt ink having the composition shown below was melt-coated on the front adhesive layer to obtain a heat-melt ink layer having a thickness of 5 μm. (Part by weight Carbon black Nigrosine base Carnauba wax Polyethylene wax Ethylene Liquid paraffin
- -□Z total 1 00 In this way, the thermal transfer recording medium of the present invention was obtained. This was repeated 10 times using a thermal printer to print on the same spot, and as a result, clear prints were obtained with higher density than the initial printing and no difference in shading even on the 10th print. Example 2 (ii Part by Weight Ink B Carbon Black Carnauba Wax Paraffin Wax Candelilla Wax Rosin Resin) 5 An ink to serve as an adhesion layer was prepared.
Hot null 1-coated on 5μ polyethylene terephthalate film and coated with 57A thick adhesive layer:)
Next, a hot-melt ink with the following composition was added. The adhesive layer 1 is melt coated with a 1' layer 7.
μ hot melt ink layer 11? Ta. Carbon black, Final Blue, Luna Bawanox, polyethylene wax, lanolin, mono-J acid, vinyl chloride, 3, total 100 10 parts by weight of ink B thoroughly melted and dispersed with three hot rolls. and 30 parts by weight of polyvinyl alcohol were placed in a ball mill and heated and mixed at 120° C. In this manner, a thermal transfer recording medium II of the present invention was obtained. This was repeated 10 times using a thermal printer, and as a result, 11 more high-density prints were made than the first time, and clear prints were obtained with no decrease in print density even after increasing the number of prints. [Effects of the Invention] Since the thermal transfer recording medium according to the present invention has the above-described structure, it is possible to print at high density more times than conventional thermal transfer recording media designed for multiple uses. In addition, there is no reduction in print density with the number of times of use, and there is an effect of reducing the shading of one character.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing an embodiment of a thermal transfer recording medium of the present invention. ■...Hot melt ink 2...Adhesive layer 3...Support 2a...Hot melt ink 2b constituting the adhesive layer...Heat-resistant resin constituting the adhesive layer

Claims (2)

[Claims] (1) A heat-fusible ink layer that is solid at room temperature and becomes liquid upon heating is provided on the support, and a heat-fusible ink and a heat-resistant resin are provided between the hot-fusible ink layer and the support. A heat-sensitive transfer recording medium characterized by having an adhesive layer interposed therebetween. (2) Thermal transfer according to claim 1, characterized in that the ratio of the heat-melting ink and the heat-resistant resin constituting the adhesive layer is 5:95 to 90:10 by weight. recoding media.