JPH0564973A - Thermal transfer recording medium - Google Patents

Abstract

PURPOSE:To provide a thermal transfer recording medium having a superior thermal sensitivity for high speed printing, and forming an image which has significant smearless properties (friction and scratch resistances). CONSTITUTION:The subject thermal transfer recording medium consists of a transfer layer based on particles, each being composed of a thermal fusing agent which is solid at normal temperature and has a melting point or a softening point of 50 deg.C or lower, and a thermal fusing material as well as dye and/or pigment formed on a support.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a thermal transfer recording medium, and more particularly,
The present invention relates to a (smearless type) thermal transfer recording medium having high abrasion resistance.

[0002]

2. Description of the Related Art Conventionally, it has been proposed to form a transfer layer with heat-fusible particles. Such a transfer layer is more flexible than a continuous layer of heat-fusible material, and the transfer layer is cut during transfer. There is an advantage that it becomes easier.

However, in the case of high-speed printing, the transfer layer formed of such heat-fusible particles may be transferred to such a degree that the transfer layer is softened, and the printed portion of the transfer layer is continuously melted. Since it does not form a layer, an image with white spots is formed when printed on a receiving paper having a low surface smoothness.

Further, in order to form a transferred image having excellent abrasion resistance, it is necessary to use a material having a high mechanical strength as a material for the transfer layer. Then, as a material having excellent mechanical strength, a thermosoftening resin is first considered, but it is difficult to peel it off from the support because of its high viscosity at the time of melting and the appearance of adhesiveness at the time of melting, so that the heat sensitivity is high. Is low.

Wax has a low viscosity at the time of melting, but wax having excellent mechanical strength is hard and brittle.
When used as a continuous layer, it is inflexible, so the transfer layer may peel off from the ribbon substrate during ribbon transfer. If a resin is added to prevent this, there arises a problem that the thermal sensitivity is lowered.

[0006]

SUMMARY OF THE INVENTION In order to solve the above problems, the present invention is capable of forming a good image even on a receiving paper having excellent heat sensitivity and low surface smoothness, and has an abrasion resistance (smearless property) of the image. The present invention aims to provide an excellent thermal transfer recording medium.

[0007]

The constitution of the present invention for solving the above-mentioned problems is a thermal transfer recording medium as described in the claims.

More specifically, the present invention imparts flexibility to the transfer layer by granulating a heat-fusible material having excellent mechanical strength so that printing can be performed even at a temperature below the melting temperature of the particles. A transfer layer is formed by localizing a low-melting-point heat-bonding agent to the particles so that the portion is likely to be a continuous layer. When the transfer layer contains a dye and / or a pigment, it can be used as an ink layer. With this layer, a good image can be obtained even on a receiving paper having excellent thermal sensitivity and low surface smoothness. Moreover, by selecting the material, it is possible to impart smearlessness to the image at room temperature, but it cannot be said to be sufficient smearlessness because the dye and / or pigment is present on the image surface.
It is difficult to maintain smearlessness at a high temperature of 50 ° C.

Therefore, more preferably, the above-mentioned transfer layer (containing no dye and / or pigment) is used as a first transfer layer, and a dye and / or pigment and a heat-meltable material are mainly contained on the layer. With a structure in which two transfer layers are laminated, a colorless layer is present on the image surface after transfer, so that smearlessness of the image is improved as compared with the case of one layer. Similar to the first transfer layer, the second transfer layer may be formed by granulating a heat-meltable material or may be a continuous layer, and may be determined according to the heat-meltable material to be used. When the second transfer layer is composed of particles of a heat-meltable material, it is preferable to include a heat-fusion agent. However, the heat fusion agent may be contained even when the second transfer layer is not composed of particles.

Since the transfer layer is composed of particles, flexibility is imparted and shear strength is lowered. Further, by localizing the heat-melting agent having a low melting point to the particles, the layer is easily formed into a continuous layer by heating during printing, and the boundary with the non-printed portion becomes clear. The shear strength of the continuous layered portion increases, the continuous layer is not easily cut, and the printed portion is transferred on the surface, so that white defects do not occur even in the receiving paper having low surface smoothness.

By localizing the heat fusion agent in the particles (mainly on the surface of the particles), the heat fusion function can be expressed with a small amount, the thermal sensitivity can be improved, and the material excellent in mechanical strength can be obtained. It is possible to obtain a transfer image excellent in smearlessness without deteriorating the characteristics of. That is, it is possible to improve both thermal sensitivity and smearless compatibility.

For this purpose, it is preferable that the heat fusion agent also has a function as a dispersant, and an anionic, nonionic or cationic surfactant can be used. Among them, nonionic surfactants, especially nonionic surfactants are preferable.
Among them, polyoxyethylene compounds are particularly preferable. More preferably, at least one selected from the following is used.

Polyoxyethylene nonyl phenyl ether Polyoxyethylene alkyl allyl ether Polyoxyethylene oleyl ether Polyoxyethylene alkylphenyl ether Polyoxyethylene lauryl ether Polyoxyethylene cetyl ether Polyoxyethylene stearyl ether Sorbitan monostearate sorbitan monopalmitate sorbitan Tristearate sorbitan distearate polyoxyethylene sorbitan monostearate polyoxyethylene sorbitan tristearate The content is 0.01 to 100 parts by weight of the first transfer layer.
30 parts by weight are contained.

Further, with respect to 100 parts by weight of the second transfer layer,
0.01 to 10 parts by weight is contained. The amount of adhesion is 0.3 to 5 g / m ² for the first transfer layer and 0.5 to 3 g for the second transfer layer.
/ Total coating weight in m ² is is suitably a 1.5～6G / m ^2.

The particle size is 0.1-10 μm in average particle size.
m, preferably 0.3 to 5 μm.

The heat-melting material used in the present invention preferably has a melting point or softening point of 60 to 130 ° C. and a penetration of 2 or less at 25 ° C. as a main component, and a material satisfying this condition is preferable. The following waxes are specifically mentioned, but not limited thereto. That is, carnauba wax,
Rice wax, candelilla wax, polyethylene wax, Fischer-Tropsch wax, montan wax, hydrogenated castor oil, montan wax derivative,
Paraffin wax, a paraffin wax derivative, aicrocrystalline wax, a microcrystalline wax derivative and the like.

The transfer layer may further contain a water-soluble resin as a binder. Specific examples of these water-soluble resins include, for example, polyvinyl alcohol, methoxycellulose, hydroxyethyl cellulose, carboxymethyllose, polyvinylpyrrolidone, poly There are acrylamide, starch, gelatin, etc.

Besides, as the thermoplastic resin, various resins having a melting point or a softening point of 70 to 140 ° C. can be used. For example,
There are acrylic resin, methacrylic resin, styrene resin, vinyl acetate resin, vinyl chloride resin, vinylidene chloride resin, petroleum resin, novolac resin, olefin resin, polyester resin, polyacetal resin, and copolymers thereof.

The particles used for the first transfer layer may be composed of a single heat-melting material or two or more kinds of materials.
When the particles are composed of two or more kinds of heat-meltable materials, solid solution particles are preferable. As a manufacturing method, a heat-melting material is mixed and heated to a heat-melting state to obtain a uniform solid solution, which is then dispersed or emulsified by a sand mill, a ball mill, a jet mill or the like to have an average particle diameter of 0.1 to 10 μm. To get.

The first transfer layer may be composed of a single particle or two or more kinds of different particles. As the support of the thermal transfer recording medium in the present invention, various conventionally known materials can be appropriately used. Specifically, polyester film, polyamide film, polyvinyl chloride film, polyethylene film, polypropylene film,
Examples thereof include plastic films such as polyimide film, polysulfone film, and polycarbonate film, and condenser paper.

The thickness of the support is preferably 2 to 15 μm when a thermal head is considered as a heat source for thermal transfer. For example, a heat source capable of selectively heating the thermal transfer ink layer such as laser light is used. When used, there is no particular limitation. Further, when a thermal head is used, a heat-resistant protective layer made of silicon resin, silicon rubber, fluororesin, polyimide resin, epoxy resin, phenol resin, melamine resin, nitrocellulose, etc. is provided on the surface of the support that contacts the thermal head. By providing the base material, the heat resistance of the support can be improved, or a base material that cannot be used conventionally can be used.

As the dyes and pigments, inorganic or organic dyes and pigments used in printing inks, paints and the like can be used. Specific examples include carbon black, disazo yellow, brilliant carmine 6B, lake red C, phthalocyanine blue, Kayaset black KR (manufactured by Nippon Kayaku Co., Ltd.), oil yellow 3G (manufactured by Orient Chemical Co., Ltd.),
Kayaset Red K-BE (manufactured by Nippon Kayaku Co., Ltd.) and Kayaset Blue KFL (manufactured by Nippon Kayaku Co., Ltd.) are available.

To form the transfer layer, a coating solution prepared by dissolving or dispersing the components for forming the first transfer layer and the second transfer layer is applied, and the components for forming these layers are dispersed in water. There is a method of applying the prepared aqueous coating solution. Second
In the case of the transfer layer, there is also a method in which the components forming the layer are heated so that at least a part thereof is melted and then applied.

The present invention will be specifically described below with reference to Examples and Comparative Examples.

[0025]

Example A first transfer layer was formed by coating a 3.5 μm polyethylene terephthalate film with an aqueous emulsion for the first transfer layer having the composition shown in Table 1 below so that the dry film thickness would be 2.0 μm.

Then, an aqueous emulsion for the second transfer layer shown in Table 1 is coated on the first transfer layer so as to have a dry film thickness of 1.5 μm to form a second transfer layer. A thermal transfer recording medium was produced. The amounts of each component in the table are parts by weight.

[0027]

[Table 1] The transfer layer of these thermal transfer recording media was brought into close contact with the surface of the high-quality paper / or mirror-coated paper, and printing was performed using a bar code printer. (Print speed 150 mm / se
c) The image density, thermal sensitivity and smearlessness of the printed image were examined and the results are shown in Table 2 below.

[0028]

[Table 2] (Note) Image density: Reflection density of solid print part (by Macbeth reflection densitometer) Thermal sensitivity: Decoding rate of printed vertical bar code (parallel bar) was calculated with LASERCHECK 2811 (manufactured by Symbol Technologies), and the value was 90. It is represented by the minimum applied energy above. The unit is mj / mm ² .

Smearlessness Abrasion resistance: Rubbing frequency 100 reciprocations Load 100 g / cm ² -20 ° C to 50 ° C Good ... No change Somewhat bad ... A little ink is taken from the printed part and a little on the non-printed part Bad ... A lot of ink is taken and it sticks considerably to the non-printed part. Transferability: It was evaluated by whether or not the image printed on the high-quality paper with a bar code printer was clearly printed.

◯: The print is clearly transferred.

X: The print was unclear and was not partially transferred.

Scratch resistance: The transferred image was rubbed with a pen scanner to check how much ink was picked up in the printed portion.

Good ... No change Bad ... Ink is removed and the ring breaks

[0034]

As described above, the thermal transfer recording medium of the present invention has sufficient thermal sensitivity for high-speed printing and can form an image excellent in smearlessness.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Nobuyuki Maeda 1-3-6 Nakamagome, Ota-ku, Tokyo Inside Ricoh Co., Ltd. (72) Kumi Surizaki 1-3-6 Nakamagome, Ota-ku, Tokyo Stock company Ricoh

Claims (4)

[Claims] 1. A solid which has a melting point or a softening point of 50 ° C. at room temperature.
A thermal transfer recording medium having the following particles on the support, which are composed of a heat-melting agent and a heat-meltable material, and a transfer layer containing a dye and / or a pigment as main components. 2. A solid at room temperature and a melting point or softening point of 50.
A first transfer layer containing particles of a heat-melting agent and a heat-melting material at a temperature of ℃ or less as a main component, and a second transfer layer containing a dye and / or a pigment and a heat-melting material as the main components on a support. A thermal transfer recording medium characterized by having in sequence. 3. The thermal transfer recording medium according to claim 1, wherein the thermal fusion agent is a polyoxyethylene compound having a melting point of 50 ° C. or lower. 4. The second transfer layer is further solid at room temperature,
The thermal transfer recording medium according to claim 2, further comprising a thermal fusion agent having a melting point or a softening point of 50 ° C. or lower.