JPS63115793A - Thermal transfer recording material for use on thermal printer - Google Patents

Abstract

PURPOSE:To stably record with high quality at high temperatures regardless of temperature variations, by providing an ink layer comprising a wax having specified properties and a coloring agent on a base film to produce a thermal transfer recording layer. CONSTITUTION:An ink layer comprising a wax capable of being melted when being heated by heat pulses given by a thermal head and having such a supercooling characteristics as to remain in a molten state for at least 10 msec when being permitted to cool to a temperature not higher than the melting point thereof and a coloring material is provided on a base film to produce a thermal transfer recording material for use on a thermal printer. The recording material is heated by the thermal head 3, the ink thus melted makes contact with a recording paper 4B, and then remains in the molten state until it reaches a releasing position, even when being immediately cooled to a temperature not higher than the melting point thereof through diffusion of heat to the recording paper or the like, because the ink has the supercooling characteristic.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to thermal transfer recording materials, such as thermal transfer ribbons, used in thermal printers such as terminal printers, word processors, facsimile machines, ticket vending machines, and label links. be.

[Conventional technology]

Figure 3 is a cross-sectional view of a thermal transfer recording material for a thermal printer used in a conventional therma/leg lifter. For example, wax, rosin, etc.
The ink Jffl (2B) is made of resin, oil, etc., carbon black, pigment, dye, etc. and is melted by heat.

When recording using such a thermal transfer recording material, heating is performed using a thermal head (3) from the base film side of the thermal transfer recording material in a state t3 in which the recording paper is overlapped with the thermal transfer recording material. The heated ink layer melts and adheres to the recording paper. When the ink layer that is adhered to both the base film and the recording paper is peeled off, the ink in the tempered area is removed by the thermal head f. The recording is completed by transferring the layer to the recording paper that has been peeled off Rξ from the base film.

Generally, the thermal transfer process of heating, G-melting, adhesion, and peeling is completed in a few milliseconds to a few seconds for each dot, but at the time of peeling, the ink layer is either cooled and solidified or molten. The recording status differs depending on whether it is present or not.

When the ink layer adhered to both the base film and the recording paper is peeled off, the cohesive force of the ink (a), the adhesive force between the ink and the recording paper (b), and the bond between the ink and the base film The force relationship such as adhesive force (c) determines which side the ink will be transferred to.

FIG. 4 is a cross-sectional view showing the recording state when transfer recording is performed on recording paper (4A) with a high surface smoothness using a conventional thermal transfer recording material for a thermal printer, and the ink is peeled off after being cooled and solidified. When (a) > (b)
> (c), and the ink layer is peeled off from the interface with the base film. At this time, when recording paper with a high surface smoothness is used, the ink layer in the portion heated by the thermal head sufficiently adheres to the transfer paper and is transferred, resulting in good transfer recording. On the other hand, as shown in the cross-sectional view of FIG. 5, which shows the recording state when transfer recording is performed on a recording paper (4B) with a low surface smoothness using a conventional thermal transfer recording material for a thermal printer, the surface smoothness is When recording on recording paper with a low temperature, the ink layer heated by the thermal head only adheres to the convex portions of the transfer paper, and when it is peeled off, the ink layer only adheres to the convex portions of the transfer paper. The layer is transferred and remains on the base film without being transferred to the recesses, resulting in only faint, low-quality printing.

In order to obtain good printing on such recording paper with low surface smoothness, a two-layer groove structure is used in which a base film (a releasable ink layer is provided, and an ink layer with high film-forming properties is provided on the base film). It is proposed that.

This is achieved by adhering ink with high film-forming properties to the convex parts of recording paper with low surface smoothness, and peeling off the release ink layer at the part of the release layer while it is in a molten state. The bridge attempts to transfer the shape.

However, when using such a two-layer composition of a releasable ink layer and an ink layer with high film-forming properties, if the temperature during peeling is too high, the releasability of the releasable ink layer becomes high. Also, if the temperature during peeling is too low, the film-forming properties of the ink are too high, resulting in transfer to excess areas that should not be transferred, resulting in poor resolution of fine character patterns. .

In addition, because it uses flat ink with film-forming properties, it adheres only to the convex parts of the recording paper, and because it does not penetrate into the paper, the surface of the recording material is rubbed easily. There is a problem that the storage stability of recorded materials is insufficient, such as peeling off.

For example, as shown in Japanese Unexamined Patent Publications No. 60-280799 and No. 60-25781, using conventional thermal transfer recording materials, while the ink is in a molten state after printing by heating with a thermal head, It was attempted to cause cohesive peeling by peeling off immediately to obtain good prints on recording paper with low surface smoothness.

[Problem that the invention seeks to solve]

The heating time by the thermal head is generally 0.8
It is a very short time of m5 ec to several m5 ec, during which a rapid temperature rise occurs, followed by a rapid temperature drop before peeling occurs. Therefore, it is difficult to accurately control the temperature during peeling within a certain range, and it is difficult to cause stable cohesive peeling.

Furthermore, when the Thermage head suddenly heats up from a cooled state as at the beginning of the row, the amount of heat supplied to the thermal transfer recording material is small, and when it is peeled off, it cools down to a temperature below the melting point of the ink, making it difficult to use conventional thermal transfer recording. When using this material, the ink solidifies and peels off, resulting in only faint prints as shown in FIG. 5 on recording paper with low surface smoothness.

This invention was made in order to solve these problems, and it is possible to stably obtain high-density, high-quality recording even on recording paper with low smoothness, regardless of the temperature variation of the thermal head. The purpose is to obtain a thermal transfer recording material for lv1 printer.

[Means for solving problems]

The thermal transfer recording material for thermal printers of the present invention includes a base film, and is provided on the base film, melts when heated by one of the thermal baths of the thermal head, and then radiates heat and cools to a temperature below the melting point. Even if it is, 10m86
It is equipped with an ink layer containing a supercooling wax that maintains a molten state of C or higher and a coloring material.

[Effect]

The wax in this invention can maintain a supercooled state of 10 mBe or more, so even if the temperature at the time of peeling changes slightly and is cooled below the melting point of the ink, it can be peeled off stably, and the smoothness can be improved. High-quality recording can be obtained even on low-quality recording paper.

〔Example〕

The waxes related to this invention include paraffin wax, microcrystalline wax, alcohol wax, acid wax, ester wax, partially saponified ester wax, polyethylene wax, polypropylene wax, oxidized polyethylene wax, amide wax, natural vegetable wax, and natural wax. It is possible to use a wax that is a mixture of at least three kinds of animal waxes, or a wax that contains 80% or more of the microcrystalline wax, which is a branched wax, or a wax that contains 50% or more of the amide wax. It is valid.

Due to the structure of the wax as described above, the supercooling time described below is 10m$eC or more, which is higher than that of a general thermal thermometer lv7.
When used in a printer device, the ink remains molten after being transferred until it is peeled off, making it possible to achieve the object of the present invention.

fζ, which is used to prepare an ink using the wax component described above, is obtained by adding some additives and colorants such as carbon black, pigments, dyes, etc. and mixing them while heating and melting them.

As the base film, polyester, condenser paper, cellophane, polyimide, etc. are used.

Thermal transfer recording material for Therma A/7''!J printer is obtained, for example, by forming ink 11 on one side of a base film to a thickness of 1 to 10 μm by a hot melt coating method.

Further, the therma of the embodiment of the present invention shown in FIG. 1, It/
From the cross-sectional view showing the recording state when recording using thermal transfer recording material for RV printers, the ink heated by the thermal head (3) and melted adheres to the recording paper (4B), preventing it from peeling off. Before reaching the position, heat diffuses to the recording paper, heat diffuses to the thermal head board, heat diffuses into the air, etc. The cohesive force of ink 1- is maintained in a molten state due to the adhesive force between the ink layer (2) and the recording paper (4B) and the adhesive force between ink G (2A) and the base film (13). It is shown that a weak cohesive peeling occurs within the ink layer.

At this time, even if the temperature at the time of peeling is too high or too low than the ideal temperature range, the ink layer is supercooled, so it is peeled off in a molten state, and stable cohesive peeling always allows for a certain amount or more to be removed. The ink is transferred onto the recording paper and the high a
You can get 10,000 quality prints at 100% accuracy.

Finally, when transferring and recording onto recording paper with low surface smoothness, wax can be used as an ink component that can reduce the viscosity sufficiently when melted, so the ink heated by the thermal head melts and has a low viscosity. If the ink penetrates not only the convex parts but also the concave parts of the recording paper, and then peels it off in a molten state, the ink will adhere to the recording paper, even when the bonding area between the recording paper and the ink is small due to its low surface smoothness. Once the cohesive force within the ink layer is weaker than the adhesive force between the layer and the recording paper, the ink layer is cohesively peeled off, resulting in high-quality, high-a-degree prints that do not fade.

The time for maintaining supercooling property was measured as follows.

Wax containing no young colorant is applied to a thickness of 8 μm on a heating resistor 2×2 mm having a sheet resistance value of 5 Ω. Light is irradiated diagonally upward at an angle of 45°, and the light scattered from the ink layer is detected by a photomultiplier tube (PM) through an optical microscope from directly above. A voltage of 15V is applied to the heating resistor for 1m5eC. Since the wax is crystalline, the scattered light initially becomes PM.
However, when voltage is applied, it melts and forms a uniform layer (
The amount of scattered light is reduced. Subsequently, the wax is cooled and crystallized, so that the amount of scattered light increases again. Since these phenomena occur in a short period of time from several m5ec to several tens of m86C, P
The output of M needs to be recorded using digital memory. Figure 2 shows the voltage applied (o in the figure) measured as described above.
A characteristic diagram showing a change over time (msec) in reflected light intensity from 100 msec) is shown, and in the figure, the time (8) until the reflected light intensity returns to its original state is defined as supercooling time.

In FIG. 2, the horizontal axis represents time (msec), and the vertical axis represents reflected light intensity, which increases toward the top.

This invention will be explained in more detail below with reference to Examples.

Example 1 4 parts of Nauba wax, which is a natural vegetable wax, 8 parts of ester wax, and 8 parts of alcohol wax were mixed together.

When we measured the time for which the mixed wax and each single wax maintained their supercooling properties using the method described in the text, we found that:
25m5ecs for mixed wax, 8m3ecs for carnauba wax, 6m5ecs for ester wax and alcohol wax.The surface temperature was measured using an infrared radiation thermometer when a voltage of 15V was applied for 1m5ec to a 2x2mm heating resistor with a zero sheet resistance of 5Ω. However, the temperature suddenly rose due to the voltage application, reaching a maximum of 240℃.
(As soon as this temperature was reached and the voltage of 1m5eC was completed, the temperature suddenly decreased, and after 4m5eC, it became below 70-80℃, which is the melting point of wax.) From this, it can be seen that the wax alone measured this time was not cooled after melting. When the temperature drops below the melting point, it crystallizes immediately within a short time of 2 to 4 m5ec, whereas
It can be seen that by using a mixed wax, the supercooling property is greatly increased.

A thermal transfer ink was prepared using mixed wax as the main component and carbon black was added as a coloring pigment, and this was used as a thermal transfer recording material for a thermal printer using an example of a polyester film with a thickness of 5.7 μm. Created.

Using a thermal head with a density of 9.5 dat/mm,
Recording was performed by applying a pulse voltage of 0.6 msec with a power of 0.6 W, and the thermal transfer recording material for a thermal printer and the recording paper were separated at an angle of 60° at a distance of 1 mm from the heat generating part of the thermal head. Note that the time required for the film to be peeled off from the heat generating part was 11 msec.

Furthermore, the thermal transfer recording material for thermal printers according to one embodiment of the present invention has a shoulder density (reflection degree (OD
It was possible to record with a value of 1.2 or higher), and the ink surface had no gloss, indicating that it had coagulated and peeled off.

Comparative Example A thermal transfer recording material for a thermal printer was prepared in the same manner as in Example 1 using the single wax in Example 1, and recording was performed in the same manner as in Example 1.
On paper with a high surface smoothness of 20 seconds, a relatively high 0 degree (OD value of 1.1 or more) could be recorded, but on paper with a low surface smoothness of 20 seconds, a low density COD value of 0.0 degrees was recorded. In addition, the surface of the transferred ink was glossy, indicating that it had peeled off from the interface between the ink and the polyester film substrate.

Example 2 A thermal transfer ink was prepared by mixing microcrystalline wax in a ratio of 5 parts and alcohol wax in a ratio of 5 parts, and adding carbon black as a coloring pigment, and uniformly coated it on a polyester film with a thickness of 5 to 7 μm. A thermal transfer recording material for a thermal printer according to another example was prepared. The time during which this wax component maintained its supercooling property was 40 msec.

Thermal transfer recording was carried out in the same manner as in Example 1 using this thermal transfer recording material for thermal printers. High-density recording with an OD value of 1.2 or more was possible on both paper with a surface smoothness of 300 seconds and paper with a surface smoothness of 20 seconds, and the recording surface had no gloss, indicating that it was coagulated and peeled off.

Example 8 A thermal transfer ink was prepared by mixing amide wax in a ratio of 6 parts and oxidized paraffin wax in a ratio of 4 parts, and adding a car pump hook to the mixture, and uniformly coating it on a 5.7 μm thick polyester film. Furthermore, another example of thermal transfer recording material for Therma Iv7''!
It was m5ec. Using this, thermal transfer recording was performed in the same manner as in Example 1.

The recording surface is not glossy, indicating that it has been cohesively peeled off.
Both paper with a surface smoothness of 300 seconds and paper with a surface smoothness of 20 seconds have an OD value of 1.
A high concentration of 2 or more was recorded.

〔Effect of the invention〕

As explained above, the present invention provides a base film and a film that is provided on the base film, melts when heated by the heat pulse of the multi-head, and then radiates heat and cools to a warm box below the melting point. By using an ink layer containing supercooling wax and coloring material that maintains a molten state for 10 m5 ec or more even when the paper is molten, high-density, high-quality recording can be achieved even on recording paper with low smoothness. Therma A/7 can be obtained stably regardless of the fluctuation of the thermal head by m degree! A thermal transfer recording material for printers can be obtained.

[Brief explanation of the drawing]

Figure 1 is a sectional view showing the state of recording using a thermal transfer recording material for a thermal printer according to an embodiment of the present invention, and Figure 2 is a diagram showing the supercooling time of wax according to the present invention. Reflected light intensity from voltage application over time (m
sec) characteristic diagram showing the change, Figure 8 shows the conventional Therma A/
Figure 4 is a cross-sectional view of a thermal transfer recording material for a thermal printer used by a 7"! FIG. 5 is a cross-sectional view showing the recording state when transfer recording is performed on a recording paper with a low surface smoothness using a conventional thermal transfer recording material for Therma A/7"! printer. In the figure, (1) is the base film, (2A) is the ink layer containing supercooling wax, (3) is the thermal head, and (4B) is the recording paper with low surface smoothness. The same reference numerals in each figure indicate the same or corresponding parts.

Claims (4)

[Claims] (1) A base film and a material provided on this base film that melts when heated by a thermal pulse of a thermal head and then radiates heat and cools to a temperature below the melting point.
A thermal transfer recording material for a thermal printer, comprising an ink layer containing a supercooling wax that maintains a molten state for 0 msec or more and a coloring material. (2) The wax is paraffin wax, microcrystalline wax, alcohol wax, acid wax,
Claim 1, which is a mixture of at least three of ester wax, partially saponified ester wax, polyethylene wax, polypropylene wax, oxidized polyethylene wax, amide wax, natural vegetable wax, and natural animal wax. Thermal transfer recording material for thermal printers. (3) The thermal transfer recording material for a thermal printer according to claim 1, wherein the wax contains 30% or more of microcrystalline wax, which is a branched wax. (4) The thermal transfer recording material for a thermal printer according to claim 1, wherein the wax contains amide wax in an amount of 50% or more.