JPS59224393A - Thermal transfer material and thermal transfer recording method using the same - Google Patents

Abstract

PURPOSE:To print with faborable thermal transferrability and with favorable quality even on a recording medium having poor surface smoothness, by a method wherein a thermal transfer material comprising a powder of a magnetic material dispersed in a thermally transferrable ink layer is used, and thermal transfer recording is conducted under the action of a magnetic attracting force. CONSTITUTION:The thermally transferrable ink layer 3 comprising a powder 5 of a magnetic material dispersed in a heat-fusible binder 4 is provided on a base 2 consisting of a known film, paper or the like. A wax, a higher fatty acid, a thermoplastic resin or the like is used as the heat-fusible binder. A powder of a ferromagnetic element such as iron and cobalt or a compound such as magnetite and hematite may be used as the powder of magnetic material, and the powder having an average particle diameter of 0.01-10mum is used in the ink layer 3 in an amount of 3-90%. A recording medium 6 is faced to the thermal transfer material 1, a permanent magnet 7 functioning also as a platen is placed on the back side of the medium 6 to exert a magnetic attractive force, and in this condition, thermal transfer is conducted by a thermal head 8.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a thermal transfer recording method that provides excellent thermal transfer performance, particularly good print quality even on recording media with poor surface smoothness, and a thermal transfer material used therein.

In recent years, with the rapid development of the information industry, various information processing systems have been developed, and recording methods and devices suitable for each information processing system have also been developed and adopted. As one of the methods, the thermal recording method has been widely used recently because the device used is lightweight, compact, noiseless, and has excellent operability and maintainability.

However, among the recording papers used in thermal recording methods, ordinary thermal recording paper is a color-forming processed paper containing a color former and a color developer, so it is expensive, and records can be tampered with. The paper has disadvantages in that it has poor storage stability, such as the paper easily developing color due to heat or organic solvents, and the recorded image fading in a relatively short period of time.

In order to maintain the advantages of the thermal recording method mentioned above and compensate for the disadvantages associated with the use of thermal recording paper, the thermal transfer recording method has recently been particularly noted [1]. Generally, a heat-sensitive transfer material is used, which is formed by melt-coating a heat-transferable ink consisting of a colorant dispersed in a heat-melting binder onto a sheet-like support, and the heat-transferable ink layer records the heat-sensitive transfer material. The ink layer is superimposed on the recording medium so as to be in contact with the medium, and heat is supplied from the support side of the thermal transfer material using a thermal head to transfer the melted ink layer onto the recording medium. It forms a transfer ink image. According to this method, it is possible to maintain the above-mentioned advantages of the heat-sensitive recording method and to use paper as a recording medium, and also to eliminate the drawbacks associated with the use of heat-sensitive recording paper as described in 2.

However, conventional thermal transfer recording methods are not without drawbacks. The reason is that in conventional thermal transfer recording methods, the transfer recording performance, that is, the printing quality, is greatly affected by the surface smoothness. Good printing is performed on highly smooth recording media, but when recording media with low smoothness are used, This means that the print quality deteriorates significantly. However, even when using paper, which is the most typical recording medium, highly smooth paper is rather special, and ordinary paper has various degrees of unevenness due to the entanglement of [I]. Therefore, in the case of paper with large surface irregularities, the hot-melted ink cannot penetrate into the paper fibers during printing and only adheres to the convexities on the surface or the vicinity thereof, resulting in sharp edges of the printed image. The image may be missing, or part of the image may be missing, resulting in a decrease in print quality. Additionally, in order to improve printing quality, it is possible to use a heat-melting binder with a low melting point.
In this case, the thermal transfer ink layer becomes sticky even at relatively low temperatures, resulting in disadvantages such as decreased storage stability and staining of non-printed areas of the recording medium.

In addition, in order to eliminate inconveniences such as missing prints without causing such deterioration in storage stability, increasing the amount of heat supplied or increasing the heating time may eliminate the missing prints, but this may result in a decrease in recording sensitivity. Alternatively, the thermal transfer speed decreases, and furthermore, the print becomes thicker, resulting in a decrease in the sharpness of the recorded image.

1: The main object of the present invention is to eliminate the drawbacks of the conventional thermal transfer recording method mentioned above, maintain various thermal transfer performances, and 1.
To provide a thermal transfer material capable of giving high-quality prints not only to recording media with good surface smoothness but also to recording media with poor surface smoothness, and to provide a thermal transfer recording method using the same. According to the inventor's research, in order to achieve the above object, a thermal transfer material in which magnetic powder is dispersed in a thermal transfer ink layer is used, and a thermal transfer recording method is applied to the effect of magnetic attraction force. It has been found that it is extremely effective to carry out the In other words, by doing this, the transfer ability of the molten ink to the recording medium is not only due to the adhesive force or penetrating force of the molten ink, but is promoted by the magnetic attraction force of the magnetic powder, and is transferred to the surface of the recording medium. Because it adheres well to concave areas,
A transferred recorded image can be formed with good print quality even on a recording medium with poor surface smoothness.

The heat-sensitive transfer material of the present invention is based on such findings, and more specifically, the heat-transferable ink layer is formed on a support, and the heat-transferable ink layer has magnetic powder dispersed therein. It is characterized by being made of a heat-melting binder. Further, the thermal transfer recording method of the present invention provides a thermal transfer material in which a thermal transfer ink layer made of a thermal melt binder in which magnetic powder is dispersed is formed on a support, and the thermal transfer ink layer is formed on a recording medium. The recording medium is laminated so as to face each other, and the resulting laminate of the thermal transfer material and the recording medium is
The thermal transferable ink layer of the thermal transfer material is heated in a pattern while exerting a magnetic attraction force from the thermal transfer material toward the recording medium, and after the recording medium and the thermal transfer material are separated, thermal transfer ink according to the heating pattern is applied onto the recording medium. It is characterized by leaving behind an image.

Furthermore, prior to the present invention, in order to form a homogeneous magnetic coating film on a support with poor surface smoothness, a method was known in which a magnetic field is applied after applying a magnetic coating; The reality is that if the viscosity is low enough to provide the necessary coating properties, the magnetic powder in the magnetic coating material and the vehicle will separate, making it impossible to form a homogeneous magnetic coating film. However, in the case of the present invention, the relatively thin thermal transferable ink layer and the recording medium are located in close proximity to each other, and when the thermal transferable ink layer is heated, the magnetic attraction force acts before the viscosity becomes excessively low. Since the transfer is carried out using the magnetic powder, there is also the advantage that good transfer can be carried out without separation of the magnetic powder from other components.

Hereinafter, the present invention will be explained in more detail with reference to the drawings as necessary. In the following description, "%" and "part" expressing quantitative ratios are based on weight ri1 unless otherwise specified.

FIG. 1 is a cross-sectional view in the thickness direction of a thermal transfer material in the most basic embodiment of the present invention. That is, thermal transfer material l
is usually a sheet (used to include film)
A thermally transferable ink layer 3 is formed on a support 2 having a shape.

As the support 2, conventionally known films and papers can be used as they are.1 For example, films of relatively heat-resistant plastics such as polyester, polycarbonate, triacetylcellulose, nylon, polyimide, cellophane, parchment paper, etc. can be suitably used. The thickness of the support is preferably about 2 to 15 microns when considering a thermal head as a heat source during thermal transfer, but for example, a heat source such as a laser beam that can selectively heat the thermal transferable ink layer is used. There are no particular restrictions when using a thermal head, and when using a thermal head, the surface of the support that comes into contact with the thermal head may be made of silicone resin, fluororesin, polyimide resin, epoxy resin, phenolic resin, melamine resin, nitrocellulose, etc. The heat resistance of the support can be improved by providing a heat resistant material consisting of 4G, or it is possible to use a support material that could not be used conventionally.

The thermally transferable ink layer 3 is formed by dispersing magnetic powder 5 in a thermally meltable binder 4 .

As the heat-melting binder 4, carnauba wax,
Waxes such as paraffin wax, Sasol wax, microcrystalline wax, and castor wax;
Stearic acid, palmitic acid, lauric acid, aluminum stearate, lead stearate, barium stearate, zinc stearate, zinc palmitate, methyl hydroxystearate, glycerol monohydroxystearate I - higher fatty acids or metal salts thereof, Derivatives of esters; polyethylene, polypropylene, polyisobutylene, polyethylene wax, polyethylene oxide, polytetrafluoroethylene, ethylene-acrylic acid copolymer, ethylene-ethyl acrylate copolymer, ethylene-
Thermoplastic resins made of olefins alone or copolymers, such as vinyl acetate copolymers, or derivatives thereof, are used. These heat-melting binders may be used alone or in a mixture of two or more.

As the magnetic material constituting the magnetic powder 5, any material generally known as ferromagnetic material may be used, such as iron,
Metals of ferromagnetic elements such as cobalt, nickel, and manganese, alloys based on these elements, or magnetite,
Examples include oxides of these elements such as hematite and ferrite, as well as other compounds containing these ferromagnetic elements.

The magnetic powder 5 generally has an average particle size of 0.01 to 1.
0 #L is used, preferably 0.05 to 5 L. The magnetic powder 5 is preferably contained in the thermal transfer ink layer 3 in an amount of 3 to 90%, particularly 5 to 80%.

In addition to the magnetic powder 5 described above, the thermal transfer ink layer 3 may contain a coloring agent as necessary to increase the density or adjust the color tone of the thermal transfer ink layer 3. As the agent, various dyes, pigments, carbon black, etc. that are widely used in the fields of printing and recording can be used.

The heat-sensitive transfer material 1 according to the present invention includes a heat-melt ink obtained by melting and kneading components such as the above-mentioned heat-melting binder, magnetic powder, and optionally used colorants and other fillers. It is coated on the body 4 and cooled and solidified to a thickness of 1 to 30 mm. , preferably by forming a thermally transferable ink layer 3 of 2 to 20 IL.

Next, a typical embodiment of the thermal transfer recording method of the present invention using the thermal transfer material described in item 1 will be explained. FIG. 2 is a cross-sectional view of the heat-sensitive transfer material in the thickness direction showing its outline. That is, the recording medium 6 is placed opposite to the thermal transferable ink layer 3 of the thermal transfer material 1, and a permanent magnet 7 which also serves as a platen is placed on the back surface of the recording medium to apply a magnetic attraction force from the thermal transfer material 1 to the recording medium 6. A thermal head 8 applies heat pulses to locally heat the ink layer 3 in accordance with a desired printing or transfer pattern. The heated portion of the ink layer 3 is melted, and due to its adhesive force and the magnetic attraction force acting on the magnetic powder, it is transferred and sticks to four parts of the surface of the recording medium 6, and after the thermal transfer material 1 is peeled off, the image is printed on the recording medium 6. Gives a transfer recorded image of good quality.

In the example L, an embodiment was described in which the thermal transferable ink layer of the thermal transfer material and the recording medium come into contact during thermal transfer. However, in the transfer recording method of the present invention, the force necessary for transferring the thermal transfer ink is given by the magnetic attraction force directed from the thermal transfer material toward the recording medium due to the nature of the wood. The thermal transferable ink layer and the recording medium may be separated from each other by some distance. Therefore, the stacked state of the thermal transfer material and the magnetic recording medium in the present invention includes such a state where they are stacked facing each other with a slight distance between them.

In order to apply a magnetic attraction force from the thermal transfer material 1 toward the recording medium 6, any magnetic field generating means such as an electromagnet other than a permanent magnet may be used. Although the strength of the magnetic field is not particularly limited, a strength of 400 degrees or more is preferably used. It is also easy to understand that other heat sources such as laser light can be used in addition to the thermal head as the heat source for thermal transfer recording.

As described above in detail, according to the present invention, a thermal transfer material having magnetic powder dispersed in a thermal transfer ink layer is used, and a thermal transfer recording method is performed under the action of magnetic lines of force, thereby preserving the thermal transfer material. It is possible to perform recording with good print quality even on a recording medium with poor surface smoothness while maintaining good thermal transfer performance including properties. Furthermore, improvements in recording sensitivity such as high-speed printing performance can be expected, and advantages such as the ability to magnetically read recorded images can also be obtained.

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

Example 1 Magnetic powder (7-Fe20g) 45 parts Paraffin wax (softening point 60°C) 35 parts Ethylene-vinyl acetate copolymer 5 parts (copolymerization ratio 90:10
) Carnauba wax 15 parts'' Each component was placed in a container, heated to 150°C, and uniformly dispersed using a homomixer. The resulting melt was coated on a 6IL thick polyester film using a wire bar to form a thermal transfer material having a 4IL thick ink layer. Also. The ink layer of this thermal transfer material is placed facing the recording paper, and a magnetic field of 1000 oersted is applied from the back surface of the support by a thermal head while acting on the thermal transferable ink layer of the thermal transfer material by a permanent magnet that also serves as a platen. pulse 11j
When printing was performed at 5 msec, clear print without blurring or blurring was obtained on the recording paper, and there was no difference in print quality even when recording paper with different smoothness was used.

Example 2 Magnetic powder (Fear 4) 2 parts Carbon black 5 parts Paraffin wax (softening point 60°C) 35 parts Ethylene-vinyl acetate copolymer 20 parts (copolymerization ratio 90:10) Carnauba wax 20 parts Above components A thermal transfer material was obtained in the same manner as in Example 1 except that . Using this thermal transfer material, a magnetic field of 1500 oersted was applied, a pressure of 1.6 kg/c was applied by a thermal head, and an applied pulse rl 5 msec. ), Beck smoothness was 100 sec and 30 seccy), and when printing was performed on recording paper, clear print without blurring or blurring was obtained on both recording papers.

Comparative Example 1 - When printing was carried out on two types of recording paper under the same conditions as in Example 2, except that intermittent carbon black was added in place of the magnetic material, and no magnetic field was applied, printing was performed on two types of recording paper. When printing on the recording paper for 30 seconds, the transfer efficiency from the support film was poor, and the print quality was clearly lower than in the Examples. That is, the print quality was largely influenced by the smoothness of the recording paper.

Example 3 In Example 1, Fe-Co was used instead of γ-Fe2O3.
When magnetic powder made of -14i alloy was used, the same results as in Example 1 were obtained.

[Brief explanation of the drawing]

FIG. 1 is a schematic cross-sectional view in the thickness direction of an embodiment of the thermal transfer material of the present invention, and FIG. 2 is a thermal transfer diagram showing an embodiment of the thermal transfer recording method of the present invention using the thermal transfer material of FIG. FIG. 3 is a schematic cross-sectional view of the material in the thickness direction. 1... Thermal transfer material 2... Medium support 3... Thermal transfer ink layer 4... φ Heat-melting binder 5... Magnetic powder 6... Recording medium 7... Permanent magnet that also serves as a platen 8...Heat head

Claims (1)

[Claims] 1. A heat-sensitive transfer material comprising a heat-transferable ink layer formed on a support, the heat-transferable ink layer comprising a heat-melting binder in which magnetic powder is dispersed. . 2. A heat-sensitive transfer material formed by forming a heat-melt ink layer made of a heat-melt binder in which magnetic powder is dispersed on a support is placed on a recording medium such that the heat-transferable ink layer faces the recording medium. The thermal transfer ink layer of the thermal transfer material is heated in a pattern while applying a magnetic attraction force from the thermal transfer material toward the recording medium to the resulting laminate of the thermal transfer material and the recording medium. A thermal transfer recording method characterized by leaving an image of thermal transfer ink corresponding to a heating pattern on a recording medium after separation of a thermal transfer material.