JPS6398479A - Thermal transfer material - Google Patents

Abstract

PURPOSE:To print with high density and favorable sharpness even on a recording material poor in surface emoothness, by a construction wherein heat-fusible materials in a thermally transferrable ink layer constitute at least two kinds of domains, the domains are constituted respectively of different kinds of heat- fusible resin particulates, and one of the different kinds of heat-fusible resin particulates are colored heat-fusible resin particulates. CONSTITUTION:A thermal transfer material 1 comprises a thermally transferrable ink layer 3 comprising a heat-fusible material, on a usually sheet- shaped base 2. The ink layer 3 comprises heat-fusible resin particulates of a kind A and colored heat-fusible resin particles of a kind B, and has domains each of which is constituted solely of the heat-fusible resin particules of the kind A or is constituted solely of the colored-heat-fusible resin particles of the kind B. The thermal transfer material 1 is capable of giving sharp printed images even on a recording material poor in surface smoothness, and even when the quantity of the colored component is increased for enhancing printed density, high-quality images with a high printed density can be produced without raising an applied voltage.

Description

Detailed Description of the Invention [Industrial Application Field] The present invention provides a thermal transfer material that can provide a transferred recorded image with good print quality even on a recording medium with poor surface smoothness during thermal transfer recording. Regarding.

[Prior art] In addition to the general features of the thermal transfer recording method, such as the equipment used being lightweight, compact, noiseless, and excellent in operability and maintainability, the thermal transfer recording method also uses colored paper and It has been widely used recently because it is unnecessary and has the advantage of excellent durability of recorded images.

This heat-sensitive transfer recording method uses a heat-sensitive transfer material in which a heat-transferable ink layer formed by dispersing a coloring material in a heat-melting binder is coated on a support, which is generally in the form of a sheet. is superimposed on the recording medium so that its thermally transferable ink layer is in contact with the recording medium, and heat is supplied from the support side by a thermal head to transfer the melted ink layer onto the recording medium, thereby creating a heat-supplied shape on the recording medium. (pattern) to form a transferred recorded image according to the pattern.

However, with conventional thermal transfer recording methods, the transfer recording performance, that is, the print quality or the surface smoothness of the recording medium, is greatly affected, and it is difficult to print well on highly smooth recording media. In the case of a recording medium with a low density, there is a problem that the print quality deteriorates significantly. For this reason, paper with a high surface smoothness is generally used as a recording medium, or paper with a high smoothness is rather special, and ordinary paper has various degrees of unevenness due to the entanglement of fibers. Therefore, in the case of paper with large surface irregularities, the hot melted ink during printing is transferred to the entire recording area of the paper, and it penetrates and adheres only to the convexities on the surface or the vicinity thereof, so the edges of the printed image or sharp edges. The image may be missing or part of the image may be missing, reducing print quality.

Conventionally, in order to obtain recorded images of good print quality on such recording media with poor surface smoothness, it has been necessary to use, for example, a hot-melt binder with a low melt viscosity in at least the surface layer, or a thermally transferable binder. A method has been adopted based on the idea that by increasing the thickness of the ink layer, molten ink can faithfully adhere to or penetrate into the fine uneven structure of a recording medium such as paper. However, when a binder with a low melt viscosity is used, the ink layer becomes sticky even at relatively low temperatures, resulting in problems such as a decrease in storage stability and staining of non-printed areas of the recording medium, and also causes bleeding in the transferred image. In addition, when increasing the layer thickness of the thermal transferable ink layer,
As the bleeding becomes larger, it is necessary to increase the amount of heat supplied from the thermal head, and the printing speed decreases.

Generally, methods for increasing print density include increasing the thickness of the colored ink layer and increasing the amount of coloring components added to the ink layer. However, when the layer thickness is increased, the ink layer becomes difficult to cut and chips occur, making it impossible to obtain good prints. Furthermore, if the amount added is increased, the pigments, dyes, etc. that serve as coloring components themselves do not have heat-melting properties, so the transferability upon application of heat deteriorates, making it impossible to obtain good prints. Furthermore, when the amount of the non-thermofusible material added to the ink layer is increased as described above, even higher applied energy is required to obtain the original transferability.

[Problems to be solved by the invention] The present invention solves the conventional problems, and while maintaining various thermal transfer performances, it can be used not only for recording media with good surface smoothness, but also for recording media with good surface smoothness. The purpose of this work was to provide a thermal transfer material that can print with high density and sharpness even on recording media that do not have a high density.

[Means for Solving the Problems] That is, the heat-sensitive transfer material provided by the present invention has a heat-transferable ink layer containing a heat-meltable material on a support. The heat-melting material of the layer forms two or more types of domains, and each domain is composed of different types of heat-melting resin particles, and at least one of these heat-melting resin particles is colored. It is characterized by being meltable resin fine particles.

[Detailed Description and Examples of the Invention] In the heat-sensitive transfer material of the present invention, two or more types of domains are formed of heat-melt materials in the heat-transferable ink layer, and each domain is composed of different types of heat-melt resin fine particles. Therefore, the cohesive force within the ink layer can be significantly reduced compared to a homogeneous system. These two or more types of domains proceed to fuse and become homogenized in the pattern heating section, forming a recorded latent image with high cohesive force, as well as an adhesive force that acts as an adhesive force of the recorded latent image to the recording medium. can occur. In addition, since it is composed of two or more types of domains, and there are domains with different functions or physical properties, such as adhesive strength or cohesive force when heated, the state is such that each function or physical property is more easily expressed than in the case of a homogeneous system. be able to. In this way, in the thermal transferable ink layer, there is a large difference in cohesive force between the heat-applied area (pattern heating area) and the non-heated area, so a clear recorded image can be obtained, and the recorded latent image can be By generating adhesive force to the recording medium, it is possible to form a transferred recorded image with good print quality even on a recording medium with poor surface smoothness.

In addition, since colored thermofusible resin fine particles are used as the coloring component, even when the coloring component is increased to increase the concentration, the particulate nature is maintained. The difference in cohesive force can be maintained. This allows, without increasing the applied voltage,
It is possible to form a transferred recorded image with high print density and good print quality.

The present invention will be explained in more detail below. In the following description, "%" and "part" expressing quantitative ratios are based on weight unless otherwise specified.

FIG. 1 and FIG. 2 each show one of the thermal transfer materials of the present invention.
FIG. 3 is a schematic cross-sectional view in the thickness direction showing an example.

The domain referred to in the present invention refers to the composition, composition,
Each domain, which is a region that can be distinguished from others based on physical properties, is composed of a single or a plurality of heat-melting resin fine particles.

When the same elements are represented by the same reference numerals, the thermal transfer materials 1 shown in FIGS.
have.

The thermal transferable ink layer 3 is composed of, for example, heat-melting resin fine particles of type A (indicated by an open circle in the figure) and colored heat-melting resin fine particles of type B (solid black circle in the figure), and is composed of colored heat-melting resin fine particles of type B (solid black circle in the figure). In this example, domains are formed by type A, which is a single heat-fusible fine particle, and type B, which is a colored heat-fusible fine particle. In addition, in the example shown in Fig. 2, the 1ζ main is formed by a higher-order aggregate of a plurality of A-type heat-melting resin fine particles and a plurality of B-type colored hot-melting resin fine particles, respectively. . Alternatively, there may be a mixture of domains made up of these single particles and domains made up of aggregates. In the present invention, the term "thermofusible" refers to the property of melting and becoming liquid when heat is applied, or the property of being heat softened and exhibiting adhesive strength or adhesive strength.

As the support 2, conventionally known films and papers can be used as they are, such as films of relatively heat-resistant plastics such as polyester, polycarbonate, triacetylcellulose, polyphenylene sulfide, polyimide, cellophane, or parchment paper. , condenser paper, etc. can be suitably used. The thickness of the support should be 1 when considering a thermal head as a heat source during thermal transfer.
It is desirable that the thickness be about 15 microns. In addition, when using a thermal head, a heat-resistant protective layer made of silicone resin, fluororesin, polyimide resin, epoxy resin, phenol resin, melamine resin, acrylic resin, nitrocellulose, etc. is applied to the surface of the support that comes into contact with the thermal head. By providing this, the heat resistance of the support can be improved, or it is possible to use a support material that has not been used in the past.

The thermofusible materials that make up the thermofusible resin particles include:
Wax, polyolefin resins such as low-molecular polyethylene, polyamide resins, polyester resins, epoxy resins, polyurethane resins, acrylic resins, polyvinyl chloride resins, polyvinyl acetate resins, petroleum resins,
Examples include phenolic resins, polystyrene resins, elastomers such as styrene-butadiene rubber, and isoprene rubber.

The thermofusible resin fine particles can be produced by polymerization processes such as emulsion polymerization and suspension polymerization, by mechanically dispersing the thermofusible resin using a dispersant, and by other methods such as mechanical crushing, spray try method, precipitation method, etc. Among those obtained, the softening temperature of the fine particles is 50°C to 160°C, preferably 608°C to 1
A temperature of 50°C is used. The softening temperature referred to here refers to the outflow start temperature of the sample measured using a Shimadzu flow tester CFT-500 under conditions of a load of 10 kg and a temperature increase rate of 2°C/min.

Colored thermofusible resin particles can be obtained by suspension polymerization, for example, by dissolving or dispersing coloring agents such as dyes and pigments in advance and subjecting them to suspension polymerization of colored monomers, or by using colored thermofusible resin particles. It can be obtained by a method such as mechanical crushing. The coloring materials used in this case are 1. Carbon black, Nigrosine dye, Lamp black, Sudan Fluff SM, First Yellow G, Benzidine Yellow, Pigment Yellow, In 1~First Orange, Irgazine Red, Paranitroaniline Red,
Toluidine Ret, Carmine FB, Permanent Bordeaux FRR, Picment Orange R, Lysol Red 2G, Lake Leu 1-C, Rhodamine FB, Rhodamine B Lake, Methyl Hiolet 1-B Lake, Phthalocyanine'Flu-, Pigment True Clean B, Phthalocyanine Green, Oil Yellow G, Zapon Fast Yellow CGG, Kaya Set Y
963, Kaya Set YG, Sumiplus 1-・Erow 〇G
, Zapon Fast Orange RR, Oil Scarlet, Sumiplast Orange G, Orazole Brown G
, Pomelo First Scarlet CG, Eisenspiron Red BEH, Oil Pink OP, Victoria Flu F4R, First Gen Blue 5007, Sudan Flu, Oil Peacock Flu, etc. One or more types of known dyes and pigments are used. be able to.

The average particle diameter of the hot-melt resin fine particles and the colored hot-melt resin fine particles is preferably 20 pm or less (about 0.1 JLm or less), and more preferably 10 or less (about 0.1 JLm). If it exceeds 20 ILm, it is too large, so it may be useful if the particle diameter is the same as the ink layer thickness. In this case, voids are likely to occur in the recorded latent image when the particles are fused to adjacent particles by heat application, resulting in poor transferability, which is undesirable. Further, for this reason, it is not preferable to change the particle size and the ink layer thickness.

The ratio of the different types of heat-melting resin fine particles constituting the heat-transferable ink layer can be arbitrarily selected depending on the function or physical properties of each particle, and is not particularly limited.

The layer thickness of the thermal transferable ink layer is 1 to 20 gm, more preferably 2 to 1 gm.
It is preferable to set it to 0 pm. When the thickness of the thermally transferable ink layer is as thin as less than 1 gm, the film properties of the latent image formed by heat application and fine particles fusing together becomes weak, and 20Ji.
If it exceeds m, it is difficult to uniformly fuse the particles as a whole, which is not preferable.

The planar shape of the thermal transfer material of the present invention is not particularly limited, and is generally used in the form of a typewriter ribbon or a wide tape used for line printers. Further, for color recording, a heat-sensitive transfer material may be prepared by applying heat-melting ink of several different tones in stripes or blocks.

The thermal transfer recording method using the thermal transfer material described in 2 is not particularly different from a normal thermal transfer recording method, and a heat source such as a thermal head or a laser beam can be used as a heat source for thermal transfer recording.

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

Example 1 <Ink 1> i Each component of the second prescription was thoroughly stirred and mixed until the solid content concentration was 25.
% ink was prepared. Note that the colored wax emulsion was obtained as follows.

The mixture consisting of the above was heated to too much temperature and dispersed with an attritor. This colored dispersion was emulsified in water to form an emulsion with a solid content of 20% and an average particle size of 2 JL.

Additive silicone resin for release paper at 0.3 g/m
2. Apply ink 1 using an applicator to the side opposite to the heat-resistant protective layer of the 3.5 pm polyester support with the dried heat-resistant protective layer and evaporate the water at 60°C. to form an ink layer with a thickness of 5 pm, and heat-sensitive transfer material (
1) was obtained.

<Ink 2> Ink 2 with the above formulation was applied to the same support surface as in Example 1 using an applicator and dried at 80°C to give a layer thickness of 31 Lm.
An ink layer was formed to obtain a thermal transfer material (II).

Thermal transfer recording was performed on the thus obtained thermal transfer material (I) (rI) under the following conditions.

・Thermal head Thin film head 24 dot configuration 1 dot size 0. ]4x 0.15m+m distance between dots
0.015 +aI! +・Heating element resistance value
315Ω・Applied voltage 13.2V・Applied pulse rll], 11m5ec recording paper Bond paper (Beck smoothness 7 to 8 seconds) Printing and transferability were evaluated, and the results are shown in Table 1.

Table 1 When the thermal transfer material of the present invention is used, as shown in Table 1,
It has good sharpness and transferability even on paper with low smoothness, and provides high-quality printing with higher print density than before.

[Effects of the Invention] The thermal transfer material of the present invention provides sharp prints not only on recording media with good surface smoothness, but also on recording media with poor surface smoothness. I'll come. Also,
Even when the amount of coloring components is increased to increase print density,
It is possible to provide high-quality printing with high printing density without increasing the applied voltage.

[Brief explanation of the drawing]

FIG. 1 and FIG. 2 respectively show one part of the thermal transfer material of the present invention.
FIG. 3 is a schematic cross-sectional view in the thickness direction showing an example. DESCRIPTION OF SYMBOLS 1--Thermal transfer material, 2--Support, 3--Thermal transfer ink layer, A--Thermofusible resin fine particles, B: Colored thermofusible resin fine particles.

Claims (1)

[Claims] In a heat-sensitive transfer material having a heat-transferable ink layer containing a heat-fusible material on a support, the heat-fusible material of the heat-fusible ink layer forms two or more types of domains, and each domain has a different type of heat transfer material. 1. A heat-sensitive transfer material comprising fine meltable resin particles, at least one of which is a colored heat-meltable resin fine particle.