JPS61280991A - Thermal transfer recording method - Google Patents

Abstract

PURPOSE:To provide a thermal transfer recording method enabling gradation recording, by providing a release part having no adhesive strength to a heat-meltable ink layer on a substrate. CONSTITUTION:A heat-meltable ink layer 2 and a release part 31 are supplied between a thermal head 1 and a platen roll 4 while held therebetween under pressure in opposed relation to each other. An ink layer 24 is melted by heat generated from a heat generating element 11 to which power was applied and penetrated in a recording medium 3 under pressure. When power to be applied is low, because the generation of heat is reduced and the temp. of the molten ink 24 is low and also reduced in its flowability, the ink 34 penetrated in the recording medium 3 is quickly cooled and solidified in a substrate 32 and the penetration amount of the ink is reduced. When power to be applied is high, a large quantity of the ink is deeply penetrated in the recording medium 3 before cooling and solidification. WHen the ink layer 22 is released after transfer, because the release part 31 on the surface of the recording medium 3 has no adhesive strength to the heat-meltable ink layer 22, said ink layer is released from said surface. As mentioned above, the transfer of the ink corresponding to applied power quantity is enabled and recording 33 having gradation can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a thermal transfer recording system, and particularly to a thermal transfer recording system that is excellent in gradation expression.

[Technical background of the invention and its problems]

Currently, facsimile machines, printers, copying machines, etc. are rapidly becoming popular, and among the recording methods used in these machines, thermal transfer recording is easy to maintain and operate, is highly reliable, and is a compact and inexpensive device. It is attracting attention because of its excellent qualities.

Thermal transfer recording methods include the melting method, which heats and melts an ink layer provided on a base material and transfers the recording onto plain paper, and the sublimation method, which records by providing a recording layer containing a sublimation dye on the base material and sublimating the dye by heating. There is a method. The sublimation method is capable of reproducing halftones, but the recording speed is slow, the energy required for recording is large, and the storage stability of recording is poor. On the other hand, the melting method basically allows only binary recording and cannot reproduce halftones.

Therefore, in the conventional melting method, dither pattern method is used.
For example, dots of the order of 3×5 (9 dots) or 4×4 (16 dots) are collectively considered as a pixel unit, and gradation is expressed in a pseudo manner by the number of dots recorded in the dot matrix. Another method is to express gradation using a plurality of transfer sheets of the same color tone but different densities, depending on the required density. For example, the former method is 4
If we use a ×4 dot matrix, 8 dots
Even when a recording head of 2 mm is used, the resolution is substantially reduced to 2 pixels. Furthermore, the dot pattern in the grid is conspicuous, making it difficult to reproduce natural gradations. Although the latter method is excellent in gradation reproduction, the number of thermal transfer sheets required for recording is several times that of the conventional method, and there is a lot of waste, so it is not practical. Another method is to apply heat-melting inks with different melting points onto the substrate in multiple layers, with the melting point being higher on the side closer to the substrate. Some methods attempt to reproduce gradation by transferring only the ink layer with a low melting point, and then increasing the energy to transfer the ink layer with a high melting point, but since heating is applied from the back side of the substrate, the ink layer inside the ink layer is In this case, a temperature gradient occurs in which the temperature of the lateral roots near the substrate increases. As a result, in order to heat the ink layer with a low melting point to a temperature where it melts, the temperature of the layer with a high melting point (layer closer to the substrate) must be higher than that. It is difficult to obtain good characteristics because the ink layer portion of the paper also melts and transfers. Furthermore, the method of sublimation-transferring a sublimable dye into wax and simultaneously transferring the wax onto a recording material has the same drawbacks as general sublimation-transfer recording. In addition, by balancing the adhesive force of the hot melt ink to the base material and the adhesive force to the recording material, the ink layer can be formed in the middle. The purpose is to have the same sensitivity, storage stability, simplicity, and recording stability as the conventional thermal melt transfer recording method.
Another object of the present invention is to provide a thermal transfer recording method that enables good gradation recording.

[Details of the invention]

FIG. 1 is an explanatory diagram of the thermal transfer recording method according to the present invention,
(2) is a thermal transfer film provided with a heat-melting ink layer (221) on the base material C1!11, (3) is a heat-melting ink layer (221) on the base material C1!
A peeling portion C3D having substantially no adhesive force to the ink on the base c33 having an absorbing and holding portion capable of absorbing and holding the molten ink of No. 1 on at least the surface? A recording medium for thermal transfer recording is provided, and numeral 11 indicates a thermal head which is a heating printing means with variable recording energy.

The recording medium used in the recording method of the present invention may be a substrate made of a single base sheet that itself can absorb and retain thermal transfer ink, such as roll paper or paperboard used in ordinary thermal transfer recording, or a substrate such as paper or OHP film. A fluororesin or a silicone resin in a broad sense that does not have mutual adhesion with the heat-melting ink is placed on the recording surface of a substrate such as a composite body, which has an absorbing and retaining portion capable of absorbing and retaining the thermal transfer ink of the thermal transfer film on the sheet. , applying a release material such as Ac-11 resin, stear-11 phosphates, To-11 fluoroethylene resin, wax, or a combination of two or more thereof together with a binder and a solvent as necessary by an appropriate means, Those with a peelable part formed by impregnation, spraying, or transfer, or those with a peelable part formed by mixing, kneading, dispersing, or dissolving the above-mentioned releasable substance by appropriate means when manufacturing the substrate. , or one in which the above-mentioned release agent is mixed into a binder that can penetrate and contain hot-melt ink, processed into a thin film so that the release part is located on the surface, and then bonded to the above-mentioned substrate by lamination processing, etc. It is possible to use There are no particular restrictions on the use of materials other than those mentioned above, such as suitable substrates that can be used for thermal transfer recording, or suitable release materials that do not have adhesion to hot melt ink.

In this specification, the peeling part is formed by adhering or adsorbing a peelable substance to the surface of the porous or fibrous structure material constituting the absorption/retention part by the method described above, and the structure Therefore, the peeling section allows the hot-melt ink to penetrate into the absorption-holding section through the remaining voids. At the same time, due to the so-called anchoring effect, the heat-fusible ink is held in the void portion, and the heat-fusible ink layer is separated on the surface due to the releasability of the hot-fusible ink, and the heat-fusible ink layer is separated on the surface by the peelability of the hot-fusible ink. It exhibits the property of separating and peeling off the ink layer on its surface.

As the heating printing means used in the present invention, thermal heads used in ordinary thermal recording, laser light sources, flash light sources, hot stamp molds, thermal pens, and those that combine needle electrodes and electrically resistive coatings are applicable. can.

When using a thermal head y as a heating printing means, the power supplied to each heating element can be varied by pulse width modulation, pulse number modulation, voltage modulation, current modulation, etc., depending on the desired recording density. It is desirable that

Furthermore, the thermal transfer film used in the present invention can be any film that is used for ordinary thermal transfer recording, and the base materials include polyester resin, cellophane, cellulose 11 acetate resin, 1) styrene resin, and polycarbonate. It is possible to use plastic films such as resins and polyimide resins, papers such as grain paper and capacitor paper, metal foils, or composites of the above-mentioned materials.

The heat-melting ink layer may be coated uniformly with black or any single color ink, coated repeatedly with ink of different hues in the length direction, or coated repeatedly with ink of different hues sequentially in the width direction. It is possible to apply a configuration in which the configuration is divided into two, or a configuration in which each of the above configurations is appropriately combined.

In the present invention, as shown in FIG. 1, the thermal transfer film (21) and the recording medium (3) are sandwiched between the thermal head 1]1 and the recording medium (3) so that the heat-melting ink layer and the peeling part Gυ face each other. It is fed between the platen rolls 14). The heat generated by the electric power applied to the heating element aυ melts the part of the heat-melting ink layer 12 that is sandwiched, and penetrates into the recording medium (3) due to compression, but when the applied electric power is relatively small. occurs. Since there is little heat, the temperature of the melted ink Q is low, and the fluidity is also low, so the ink (b) that has permeated into the recording medium (3) quickly (cools and solidifies) in the substrate C32, so the amount that permeates is small. In addition, when a large amount of electric power is applied to the heating element circle, the amount of heat generated is large, and the temperature and fluidity of the melted ink becomes high.
The ink that has penetrated into the ink penetrates deeper and more frequently until it cools and solidifies.

As described above (after the transfer is done, the thermal transfer film (2)
When the recording medium (3) is peeled off, the ink layer is separated and peeled off at the surface of the peeled part 00, since the peeled part 0υ on the surface of the recording medium (3) has no adhesive force to the hot melt ink machine.

As a result, an amount of heat-melting ink corresponding to the electric power applied to the heating element ttu is transferred to the recording medium (31), and a recording having a desired gradation is obtained.

On the other hand, the peeled off heat-melting ink (c) remains on the thermal transfer film (substrate c!1 of 21).

On the other hand, the principle of a conventional thermal transfer recording method is shown in FIG. Since the surface of the conventional recording medium (5) has strong adhesion to heat-melting ink, the resulting recording surface has a binary value, either all of the heat-melting ink is transferred or none of the heat-melting ink is transferred. Only historical records can be obtained.

FIG. 2 shows the characteristics of the recording reflection density versus the power applied to the thermal head in thermal transfer recording obtained by the above two recording methods. As is clear from the figure, the characteristic curve (2) of the conventional thermal transfer recording method draws a steep rising curve and exhibits binary characteristics, whereas the characteristic curve of the thermal transfer recording method according to the present invention Sample (1) shows a gentle density curve in response to changes in application element energy, indicating that it has excellent gradation recording characteristics.

Furthermore, in thermal transfer recording, it is necessary to record on the same medium recording that requires gradation, such as images, and recording that does not require gradation, such as characters and symbols. In that case,
As illustrated in FIG. 4, a specific portion 6 on the recording medium (6)
An image with gradation is recorded on υ, and other parts T
By recording characters, symbols, etc. on 63, it becomes possible to record the characters, symbols, etc. with high density with low recording energy.

As another application example of the recording method of the present invention, as illustrated in FIG. 5, it is also possible to use the thermal transfer film multiple times. It penetrates into the recording medium (3) to the extent that a sufficient recording density can be obtained, and a recording is obtained.On the base material C1! The ink remains by exactly the same mechanism as described above.Therefore, the thermal transfer film after recording in this way can be used again, and the thermal transfer film can be used many times. It becomes possible to provide

〔Effect of the invention〕

As detailed above, smooth gradation can be achieved by using the thermal transfer recording method of the present invention. It has the same sensitivity, storage stability, and simplicity as the conventional heat-melt transfer recording method.Furthermore, since the heat-melt ink penetrates into the recording medium, it produces recordings with excellent recording durability. You can get it. Furthermore, as a secondary effect, the thermal transfer film can be used many times.

[Example 1] The above composition? The mixture was heated and kneaded in a three-roll mill at 120° C. for 2 hours, and coated onto a 12 μm thick polyester film by wire bar mohetting to a thickness of 4 μm to obtain a heat transfer film.

The above composition was stirred in a ball mill at room temperature for 12 hours, and the resulting composition was coated on thermal transfer recording paper (TRW-1, manufactured by Tsuchiza Paper Co., Ltd.) with a wire bar to a dry weight of 0.8 g/rrt, and dried. It was used as a recording medium.

When printing was carried out using the above thermal transfer film and recording medium using a thermal transfer printer (manufactured by Fuji Xerox, P-6>fzt-, while increasing the voltage applied to the thermal head sequentially, a record showing good gradation was obtained. Ta.

[Example 2] The above composition was stirred in a ball mill for 8 hours, and the resulting composition was coated on thermal transfer recording paper (TRW-1 Dosama Paper #) with a wire bar to give a dry weight of o, a g/rn: It was coated and dried to form a recording medium.

When printing was performed with a thermal transfer printer (manufactured by Toshiba, TN-sooo) using the above recording medium and the thermal transfer film shown in Example 1, a recording with smooth gradation was obtained.

[Example 3] Polyester film (manufactured by Toshi, Lumirror F.

2 parts of powdered silica (manufactured by Mizusawa Chemical Co., Ltd./average particle size 2 μm), (same weight ratio below) Bo 11 urethane ()
Made in Japan, polyester resin/isocyanate type)
A mixed solution consisting of 4 parts of methyl ethyl ketone, 8 parts of methyl ethyl ketone, and 2 parts of toluene was stirred for about 20 minutes using a screw agitation type disperser, and the uniformly dispersed coating liquid was applied using a roll coater and dried to form an ink absorbing layer. was formed. The film thickness was 20μ.

Silicone varnish (KR282, Shin-Etsu Chemical) was applied as a release agent onto the absorbent layer using a bar coater and dried to obtain a recording medium.

When the thermal transfer film shown in Example 1 was similarly printed using a thermal transfer printer (manufactured by Toshiba, TN-5000), uniform and smooth recording with gradation was obtained.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram of the thermal transfer recording method of the present invention, FIG. 2 is a characteristic comparison diagram of the thermal transfer recording method of the present invention and a conventional thermal transfer recording method, FIG. 3 is an explanatory diagram of the conventional thermal transfer recording method, and FIG. The figure is an explanatory diagram of recording obtained on a recording medium according to the present invention, and FIG. 5 is an explanatory diagram of another embodiment of the present invention. 111...Thermal transfer y)' f21...Thermal transfer film (3)...Recording body Oυ...
Peeling part patent application Hitotoppan Printing Co., Ltd. Representative Kazuo Suzuki Figure 1 U ---7 Sir O Engineering Stirrup Figure 5

Claims (2)

[Claims] (1) A thermal transfer film having a heat-melting ink layer provided on a base material, and a heat-melting type thermal transfer recording ink layer on a base material having at least an absorbing and retaining portion on its surface capable of absorbing and retaining the heat-melting type thermal transfer recording ink. After sandwiching a recording medium for thermal transfer recording comprising a peeling portion having substantially no adhesive force so that the heat-melting ink layer and the peeling portion face each other, heating with variable recording energy is performed. A thermal transfer recording method, characterized in that thermal energy from a printing means is applied from the base material side of the thermal transfer film to perform recording using hot melt ink on the recording medium. (2) The thermal transfer recording method according to claim 1, characterized in that a recording medium having a peeling portion on a part of the surface is used.