JPS62267191A - Thermal transfer recording medium - Google Patents

Abstract

PURPOSE:To obtain a transfer image superior in uniformity and abrasion resistance, by a method wherein in a thermal transfer recording medium having a transfer layer mainly containing a granular coloring material bound with a binder and a wax, the coloring material has an average particle diameter of a specific range. CONSTITUTION:A thermal transfer recording medium is provided with a substrate and thereon a transfer layer mainly containing a granular coloring material consisting of a dye or pigment bound with a binder with 60-140 deg.C melting or softening point and a wax with 60-120 deg.C melting or softening point. The coloring material in use has an average particle diameter ranging 0.5-7mum. As the binder, a resin such as acrylic resin, methacrylic resin, styrene resin, vinyl acetate resin, and vinyl chloride resin is used. As the wax, for example, candellila wax, carnauba wax, rice wax, Japan wax, jojoba oil, etc. are used. The coloring material is dispersed to be 0.5-7mum in average particle diameter by a dispersing means such as an agitator, a ball mill, and an attritor.

Description

[Detailed Description of the Invention] [Technical Field] The present invention relates to a thermal transfer recording medium for performing thermal transfer recording on recording paper by utilizing the heat-melting properties of an ink layer.
It can also be applied to printers and bar printers for computers, word processors, etc.

[Prior Art] A thermal transfer medium is known in which a transfer layer consisting of a thermofusible substance such as paraffin wax, a dye 1, and a coloring agent such as a pigment is provided on a support. The disadvantage is that the abrasion resistance of the transferred image is poor due to the weak physical strength.

In order to improve this drawback, methods have been taken such as adding thermoplastic resin or making the transfer layer as thin as possible.
The former has the problem that as the resin component increases, the adhesive strength becomes stronger, making it difficult to transfer, and the thermal sensitivity deteriorates, while the latter has the problem of poor uniformity of the transferred image and a decrease in image density. Ta.

[Purpose] The present invention solves the above-mentioned problems of the prior art, and provides a method that allows transfer images with high density and excellent uniformity to be obtained on recording paper, as well as transfer images with excellent abrasion resistance. The purpose is to provide a thermal transfer recording medium.

[Structure] The structure of the present invention to achieve the above object is to form particulate dyes and/or pigments (hereinafter collectively referred to as colorants) solidified with a fixing agent having a melting point or softening point of 60 to 140°C. A thermal transfer recording medium having, on a support, a transfer layer mainly composed of a coloring material and a wax having a melting point or softening point of 60 to 120°C, wherein the average particle size of the coloring material is 0.5 to 120°C.
This is a thermal transfer recording medium in the range of 7 μm.

The transfer layer of the thermal transfer recording medium of the present invention is overlapped with a recording paper, and a desired image is formed on the recording paper by thermal printing from the back side of the thermal transfer recording medium.

As the support for the thermal transfer recording medium in the present invention, various conventionally known supports can be used as appropriate.

Examples of these include plastic films such as polyester film, polyamide film, polyvinyl chloride film, polyethylene film, polypropylene film, polyimide film, polyrelfon film, polycarbonate film, and densifier paper.

The colored material used in the transfer layer of the present invention can be made by mixing a conventionally known coloring agent, a resin as a fixing agent, and, if necessary, a plasticizer, etc., and then crushing the mixture into fine particles.

As the colorant, inorganic and organic dyes and pigments used in printing inks, paints, etc. can be used. Specific examples include carbon black, Disazo Yellow, Brilliant Cardin 6B, Lake Red C1 Phthalocyanine Blue, Kayaset Black KR (Nippon Herbal Medicine), Oil Yellow 3G (Orient Chemical), and Kayaset Red.
BE (Japanese Herbal Medicine), Kayaset Blue KFL (Japanese Herbal Medicine), etc.

Various resins having a melting point or softening point (ring and ball method JTS K 2531) of 60 to 140°C can be used as the resin for the fixing agent.

For example, acrylic resin, methacrylic resin, styrene resin,
Examples include vinyl acetate resin, vinyl chloride resin, vinylidene chloride resin, petroleum resin, novolak resin, olefin resin, polyester resin, polyacetal resin, (2) poxy prepolymer, or a copolymer thereof.

Furthermore, a plasticizer can be used as necessary to adjust the melting point or softening point of the coloring material.

Examples include dimethyl phthalate, diethyl phthalate, dibutyl phthalate, dioctyl phthalate, dicyclohexyl phthalate, di-2-ethylhexyl adipate, diethylene glycol dibenzoate, butyl stearate, triphenyl phosphate, and the like.

In any case, if the melting point or softening point of the coloring material is lower than 60°C, the abrasion resistance of the transferred image in a high-temperature environment (50 to 60°C) will be poor, and if it is higher than 140°C, the energy used for thermal transfer recording alone will be insufficient. It becomes difficult to fix, has poor abrasion resistance, or requires high-energy recording, which causes problems such as slow recording speed and shortened thermal head life.

The ratio of the colorant and the fixing agent used is preferably about 5 to 100 parts by weight per 1 part by weight of the colorant.

The coloring material used in the present invention is used in the form of fine particles with an average particle size of 0.5 to 7 μm, but if the average particle size is less than 0.5 μm, the transfer layer will become sticky and the transfer will not be carried out smoothly, causing the transfer image to deteriorate. Uniformity deteriorates. Increasing the amount of wax in order to improve this transfer performance lowers the abrasion resistance, which is undesirable.

On the other hand, if the average particle diameter exceeds 7 μm, thermal sensitivity and resolution will deteriorate, which is not preferable.

A binder is required to hold the particulate colored material on the support, and has a melting point or softening point of 60 to 1
Wax at 20°C is used.

If the wax has a melting point or softening point lower than 60° C., the applied thermal energy is consumed to melt the wax, resulting in insufficient energy to soften the coloring material. Therefore, only the wax is transferred preferentially, and the transfer of the colored material is insufficient, resulting in blurring of the transferred image and deterioration of sharpness. Further, if the temperature is higher than 120° C., high thermal energy is required for transfer.

Specific examples of waxes that meet the above conditions include vegetable waxes such as candelilla wax, carnauba wax, rice wax, book wax, and jojoba oil; animal waxes such as beeswax, lanolin, and spermaceti; montan wax;
Mineral waxes such as osichelite and ceresin; petroleum waxes such as paraffin wax, microcrystalline wax, and petrolatum; and synthetic waxes such as polyethylene wax, montan wax derivatives,
Examples include paraffin wax derivatives and microcrystalline wax derivatives.

The amount of these waxes used affects the thermal sensitivity and abrasion resistance of the transferred image. The ratio of the coloring material and wax used is preferably about 0.2 to 1 part by weight of wax per 1 part by weight of coloring material.

Although binders other than wax can be used as appropriate in the transfer layer of the espoused invention, the amount used should be kept to the minimum that does not inhibit the transfer, and should be 0 to 0.5 parts by weight per 1 part by weight of the coloring material. It is about 100%. Conventional binders can be used as these binders, such as polyvinyl alcohol, methoxycellulose, hydroxyethylcellulose-oxymethylcellulose, polyvinylpyrrolidone, polyacrylamide, starch, gelatin, acrylic resin, methacrylic resin, vinyl acetate resin, chloride Vinyl resin, vinylidene chloride resin, olefin resin, polyester resin,
Or a copolymer of these.

As the recording paper used with the thermal transfer recording medium of the present invention, plain paper, synthetic paper, plastic film, etc. can be used as appropriate.

8. The thermal transfer recording medium of the present invention is produced by mixing the above-mentioned transfer layer forming components with water or a solvent that does not dissolve the coloring material and resin particles, and dispersing the coloring material by a dispersing means such as a stirrer, a ball mill, or an attritor. Disperse the colored material so that it has a thickness of 0.5 to 71 tm, and apply it on a support so that the total solid content is 1 to 10 q/m2. It can be produced by drying at a temperature below the softening point of.

[Example] Next, the present invention will be explained in more detail with reference to Examples. Note that the amounts of each component described in Example 1, that is, "parts" and "1%" are all based on weight.

Preparation of Coloring Materials A-1 to A-5 Table 1 The compositions listed in Table 1 above were heated and kneaded in a roll mill, cooled, and ground in a jet mill. Fine particle coloring materials A-1 to A-5 were prepared.

Preparation of Coloring Materials B-'1 to B-5 The compositions listed in Table 2 above were heated and kneaded in a roll mill, cooled, and ground in a jet mill to produce Coloring Materials B-1 having the average particle size shown in Table 1. ~B=5 was produced.

Examples 1 to 6 Table 3 The compositions listed in Table 3 above were mixed uniformly using a stirring stone to prepare coating solutions.

These coating solutions were applied to polyester film-L with a thickness of 6 μm.
The coating was coated using a wire bar to give a coating weight of 4 g/m 2 after drying, and dried with warm air at a temperature of 50° C. to produce a thermal transfer recording medium of the present invention.

Comparative Examples 1 to 4 Table 4 Thermal transfer recording media of Comparative Examples 1 to 4 were prepared using the compositions shown in Table 4 in the same manner as in Examples 1 to 6.

The thermal transfer recording medium produced as described above was printed using a thermal transfer printer with the transfer layer in close contact with the surface of the high-quality paper by applying an energy of 0.6 J/dot. Furthermore, in order to examine the abrasion resistance of the printed image, the abrasion resistance (room temperature 20.50° C.) against cardboard was tested using a lab tester (Toyo Seiki!!).

The results were as shown in Table 5 below.

5th surface image density Reflection density of double solid printing area (Macbeth reflection densitometer) Uniformity Presence or absence of voids (areas where ink is not transferred) in double solid printing area Good...no voids Slightly poor...voids Slightly poor... Many voids Friction resistance: 100 times of friction, reciprocating load 100g/cm2 Good... Ink from the printed area is removed and does not reach the non-printed area. Slightly poor: A small amount of ink from the printed area is removed. A little bit of ink on the non-printing area is bad... A lot of ink is removed from the printing area and a lot of stick noise is on the non-printing area... A stick noise that occurs when the recording sheet and transfer sheet are separated Good... There is almost no sound I can't hear it.

Bad...The sound is very loud.

[Effects] As explained above, by using the thermal transfer recording medium of the present invention, the stick sound when peeled off from the recording paper is small, the image has high density and good uniformity, and has excellent abrasion resistance. A transferred image is obtained.

Patent Applicant Ricoh Co., Ltd. - Agent Patent Attorney Hidetake Komatsu Agent Patent Attorney Hiroshi Asahi Procedural Amendment (Spontaneous) July 7, 1986 Director General of the Patent Office Michibu Uga 1, Indication of Case Patent Application 1986-11.0630
No. 2, Title of the invention Thermal transfer recording medium 3, Person making the amendment Relationship to the case Patent applicant 5, Date of amendment order (voluntary) Amended to ``No ink was removed.''

Claims (1)

[Claims] Dyes and/or pigments with a melting point or softening point of 60 to 1
A thermal transfer recording medium having on a support a transfer layer mainly composed of a particulate coloring material solidified with a fixing agent at 40°C and a wax having a melting point or softening point of 60 to 120°C. A thermal transfer recording medium characterized in that the average particle size is in the range of 0.5 to 7 μm.