JPH0289689A - Thermal transfer recording medium - Google Patents

Abstract

PURPOSE:To prevent a blocking with time without deteriorating a heat sensitivity and a resolving power by providing wax fine particles on an uppermost layer of a hot melt ink layer formed on a substrate. CONSTITUTION:A hot melt ink layer 2 is provided on the surface of a substrate 1, and wax fine particles 3 are formed on the upper layer of the ink layer 2. In transfer, the heating by a thermal head from the rear of the substrate 1 melts and releases a part of an ink of the ink layer and the fine particle wax 3 and transfers them to an accepting medium. As the wax forming the fine particles, a paraffin wax, a candellila wax, a polyethylene wax, and the like are used. The wax fine particles 3 are formed as follows; a wax dispersion liquid in which the wax is finely dispersed in a low concentration is applied on the surface of the ink layer; or the hot melted wax is sprayed on the surface of the ink layer and separated out thereon by cooling. The purpose of preventing blocking can be accomplished by forming the wax fine particles of 3mum or less.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a 1.3 thermal Φ11''!j' recording medium, and particularly to a thermal transfer recording medium in which progging over time is prevented.

[Subject technology]

In recent years, thermal spatulas! Thermal transfer recording method using - has become widely used because of its advantages such as being noiseless, the device being relatively inexpensive and compact, easy to maintain, and stable printed images. ing. The 1ε thermal transfer recording medium used in such a thermal transfer recording method is made by mixing or laminating waxes such as natural wax or synthetic wax, a coloring agent, a thermoplastic resin, etc. on one side of a base material such as a polyester film. did. A heat-melt ink layer is provided.

However, in order to improve thermal transferability, such thermal transfer recording media must use a binder with a relatively low melting point as a binder for the heat-melting ink layer, which inevitably leads to a decrease in storage stability and damage to the receiving medium. Problems such as scumming of the recording paper (that is, the recording paper) are likely to occur. In particular, narrow-width ribbon-shaped thermal transfer recording media for word processors are usually rolled up before use, but during storage, a layer of heat-melting ink adheres to the back surface of the substrate, causing the material to deteriorate over time. In some cases, pancake-like blockage is produced, making it impossible to rewind and use the thermal transfer recording medium.

In order to solve these problems, 1. For example, use of waxes with a narrow molecular weight distribution (Japanese Patent Application Laid-Open No. 60-25787
(Japanese Unexamined Patent Publication No. 60-94385) or using wax fine particles subjected to hydrophilic surface treatment (Japanese Unexamined Patent Publication No. 606tz).
9or) Publication), etc., but the former requires the troublesome preparation of waxes with a narrow molecular landscape distribution, which is disadvantageous in terms of cost, and the latter has a hydrophilic wax particle surface, making it difficult to absorb moisture. There is a problem in that blocking may occur due to minutes.

Furthermore, providing a surface layer of wax (Japanese Unexamined Patent Publication No. 60-17
4692) has also been proposed, but since the entire surface layer is a wax layer, this has the disadvantage that a wax with a high softening point must be used to prevent blocking.

In addition, in order to enable continuous FA recording, spherical plastic particles protruding from the surface of the ink layer are provided (
JP-A-61-104888) and the inclusion of a mixture of solvent-adsorbing particles and polymer particles or inorganic particles in the ink layer (JP-A-61-137785) have been proposed. In this case, the plastic particles absorb heat, resulting in a decrease in thermal sensitivity, and since the plastic particles remain protruding, the contact smoothness with the receiving medium is poor, resulting in poor resolution. Also in the latter case, since solvent-adsorbing particles and inorganic particles coexist, the thermal sensitivity similarly decreases, and if these particles protrude, there is a problem that the resolution similarly deteriorates.

Furthermore, it is possible to apply a silicone resin or the like to the pack surface to prevent staining (Japanese Unexamined Patent Publication No. 55-7467), and to provide a polymer layer made of a resin emulsion on the ink layer to improve storage stability (in particular, Kaisho 62208989
However, in the latter case, the problem arises that the silicone resin on the back side transfers to the ink layer over time, reducing the fixation of the image. Since the layer is provided, a problem arises in that the thermal sensitivity is reduced.

[Problem to be solved by the invention]

As mentioned above, although some of the thermal transfer recording media that have been proposed so far have improved anti-blocking properties, they also suffer from decreased thermal sensitivity, decreased resolution or fixing performance, etc. Or they have problems that put them at an economic disadvantage.

Therefore, the object of the present invention is to
Another object of the present invention is to provide a thermal transfer recording medium that can prevent pancake-like blocking over time without reducing resolution.

[Means to solve the problem]

According to the present invention, a heat-sensitive transfer recording medium comprising a heat-melting ink layer provided on one side of a base material is characterized in that fine particles of wax are formed in the uppermost layer of the ink layer. A thermal transfer recording medium is provided.

That is, in the thermal transfer recording medium of the present invention, fine particles of wax are formed on the uppermost layer of a thermally fusible ink layer provided on a base material. Blocking over time can be prevented without reducing thermal sensitivity and resolution.

Next, the present invention will be explained with reference to the drawings.The specific structure and operation of the present invention are as follows.

In FIG. 1, the thermal transfer recording medium of the present invention includes a base material I,
It is composed of heat-melting ink JtiI2 and wax fine particles 3. That is, a heat-melting ink layer 2 is provided on the upper surface of the base material 1, and wax fine particles 3 are formed on the uppermost surface of the ink layer 2. During transfer, the base material 1 is heated by a thermal head from the back side of the ink layer 2, and a portion of the ink in the ink layer 2 and the particulate wax 3 are melted and peeled off, and transferred to a receiving medium.

Since the thermal transfer recording medium of the present invention has the above-described structure, the surface of the ink layer and the back surface of the recording medium are in contact with each other at points during storage in a rolled form, so that blocking is prevented and fine particles are formed. Since the amount of wax is small, it can be melted by the thermal energy of the sunset during recording, so it does not cause a decrease in thermal sensitivity. Moreover, since there is no decrease in thermal sensitivity, it is possible to use wax fine particles having a high softening point, and as a result, the anti-blocking effect can be further improved.

Furthermore, since the fine particles are made of wax, they are completely melted by heat during recording, and the smoothness of contact with the receiving medium is not hindered, so that there is no reduction in resolution.

The base material used in the present invention has a thickness of 3 to 10
Plastic films of about μm size, such as polyester fill polyimide film, polysulfone film, wholly aromatic polyamide film, and polyether ether ketone fill 11, are suitable.

Further, the heat-melting ink layer in the present invention contains a colorant and a binder as main components.

In this case, as the colorant, inorganic and organic dyes and pigments used in printing inks, dyes, etc. can be used, such as carbon black, titanium dioxide, red iron oxide, Lake Red C, Firth 1 to Sky blue,
Examples include benzidine yellow, phthalocyanine green, phthalocyanine blue, direct dyes, oil dyes, and basic dyes.

Paraffin wax is also used as a binder.

Waxes such as carnauba wax, microcrystalline wax, candelilla wax, polyethylene wax, styrene resins, ethylene/vinyl acetate copolymer resins, thermoplastic resins such as petroleum resins, styrene-butadiene rubber, nitrile-butadiene rubber, inbrene rubber,
Examples include rubbers such as chloroprene rubber.

In the present invention, fine particles of wax are formed on the surface of the two most layers of the heat-melting ink layer. Delilah wax, polyethylene wax, etc. may be used.

In order to form fine particles of wax on the surface of the uppermost J layer of the hot-melt ink layer, a low concentration wax dispersion containing finely dispersed wax is applied to the surface of the ink layer, or hot-melted wax is sprayed onto the surface of the ink layer. Alternatively, the wax may be melted with a solvent and sprayed onto the surface of the ink layer, and the solvent may be evaporated in a space to cause the wax to precipitate on the surface of the ink layer. The size of the formed wax fine particles is 3 .mu.m or less, preferably about 1 to 2 .mu.m, which can sufficiently achieve the purpose of preventing hair blocking.

〔Effect of the invention〕

The heat-sensitive transfer recording medium of the present invention has a structure in which fine wax particles are formed in the uppermost layer of the heat-melting ink layer, so that (a) during storage in a rolled form, the ink layer surface and recording Blocking is prevented because there is point contact with the back side of the media. (Explanation) Since there are fewer fine particle wax particles, they can be melted with a small amount of thermal energy during recording, resulting in a decrease in thermal sensitivity. (c) Since the fine core gamma particles are made of wax, the particles are completely melted by heat during recording, and the contact with the receiving medium is not hindered, so the low resolution is not affected. (2) Since there is no decrease in thermal sensitivity, it is possible to use wax fine particles with a high softening point, and the anti-blocking effect can be further improved, which is an outstanding effect.

〔Example〕

Next, the present invention will be explained in more detail with reference to Examples.

Note that all parts shown below are based on composition.

Comparative Example 1 A mixture having the following composition was sufficiently dissolved and finely dispersed to prepare a coating liquid for an ink layer.

[Coating liquid for ink layer]

Candelilla wax 40 parts 115
'F paraffin wax 80 parts carbon black 40 parts toluene
1,000 copies of the above ink layer coating liquid was then applied onto a polyester film with a thickness of 8 pm and dried to form an ink layer with a dry coating thickness of 5 units, and a thermal transfer recording medium (]) for comparison was prepared. Created.

Example 1 155 on the surface of the ink layer of the thermal transfer recording medium (1).

F paraffin wax heated and melted at 100℃,
Spray in a mist form with a spray nozzle to obtain an average particle size of approximately 2 pff.
1 of paraffin wax fine particles were formed on the surface of the ink layer to prepare a thermal transfer recording medium of the present invention.

Example 2 The 155°F paraffin wax in Example 1 was heated to 13
A thermal transfer recording medium of the present invention was prepared by forming paraffin wax fine particles on the ink 11 surface in the same manner as in Example 1 except that 5°F paraffin wax was used instead.

Example 3 Candelilla wax 2 parts Toluene 98 parts The above components were melted by heating and applied to the surface of the ink layer of a thermal transfer recording medium (H).
The thermal transfer recording medium of the present invention was prepared by spraying the wax while it was heated and melted to form fine particles of candelilla wax having an average particle size of 1-1 on the surface of the ink layer.

Example 4 Candelilla wax 2 parts Toluene 98 parts The above components were finely dispersed to have a candelilla wax average particle size of 2 μm, and this was sprayed onto the surface of the ink layer of the thermal transfer recording medium (1).
A thermal transfer recording medium of the present invention was prepared by forming candelilla wax fine particles with an average particle size of 2p111 on the surface of ink 1G.

Example 5 10% of the candelilla wax fine dispersion in Example 4
After diluting it twice as much, apply a thermal transfer mark to the surface of the ink layer of the medium (1) using a 0.1 mm wire bar to form fine particles of candelilla wax on the surface of the ink 11. 1. A thermal transfer recording medium was prepared.

Comparative Example 2 The surface of the ink layer of the thermal transfer recording medium (1) was heated to 155°F.
Paraffin wax ream 2. +'t JM to 2μmJ'
%, and a heat-sensitive transfer recording medium for one bite was created.

Comparative Example 3 In addition to the ink layer coating liquid in Comparative Example 1, an average particle size of 7μ was added.
An ink layer in which the polyacrylic particles protruded from the surface of the ink layer was formed in the same manner as in Comparative Example 1, except that 10 parts of polyacrylic particles of m were added as the coating liquid for the ink layer. A heat-sensitive transfer recording medium was created.

Using the thermal transfer recording medium created as described above,
Word processor t7 server: MYRIPORT JP90FX
It was printed using [; i$l manufactured by Ricoh]. The resolution and sensitivity σ at that time are shown in Table 1. In addition, the thermal transfer recording medium was subjected to a storage stability test, and the presence or absence of blocking was determined by tiJI7. The results are also listed in Table 1.

Solution'% Iσ: Number of lines that can be read in an image printed at 8 lines/mm Iσ: Macbeth Density blocking: 45. Presence or absence of bronking after waiting for 10 hours at 55 and 65°C (pancake-like 1st As is clear from Table 1, it can be seen that the thermal transfer recording medium of the present invention can prevent blocking without causing a decrease in resolution and sensitivity.

[Brief explanation of drawings]

FIG. 1 is a schematic cross-sectional view of a thermal transfer recording medium according to the present invention. ■ Base material, 2. 5 layers of heat-melting ink, 3. Fine particles of wax. Patent issued by 11 people Rico Co., Ltd. Note) O: None, ×: Occurred.

Claims (1)

[Claims] (1) A thermal transfer recording medium comprising a heat-melting ink layer on one side of a base material, characterized in that fine particles of wax are formed in the uppermost layer of the ink layer. Medium.