JPH0280292A - Thermosensitive transfer material - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a two-color thermal transfer material for transferring a two-color recorded image onto a recording medium such as plain paper.

(Prior art) The thermal transfer recording method has the general characteristics of a thermal recording method such that the equipment used is lightweight, compact, noiseless, and has excellent operability and maintainability. In addition, it eliminates the need for colored processed paper. It is also characterized by excellent durability of recorded images, and has recently been widely used.

This thermal transfer recording method generally uses a thermal transfer material formed by coating a sheet-like support with a thermal transferable ink made of a heat-melting binder and a colorant dispersed therein. The ink layer is superimposed on the recording medium so as to be in contact with the recording medium, and heat is supplied from the support side of the thermal transfer material by a thermal head to transfer the melted ink layer onto the recording medium. A transfer recording image is formed thereon in accordance with the shape of heat supply.

In recent years, there has been a strong demand in the market to obtain two-color printing while taking advantage of the advantages of the thermal transfer recording method, and various techniques for obtaining two-color printing have been proposed.

JP-A No. 56-148591 discloses that two heat-melting high melting point ink layers A and a low melting point ink layer B containing different colorants are sequentially laminated from the base material side on a support. In the case of applied energy, low melting point ink layer B
By transferring only the ink layer onto plain paper, and in the case of high heat application energy, transferring both the heat-melting ink layers A and B,
A two-color thermal transfer recording element is disclosed that provides a two-color recorded image.

Furthermore, JP-A No. 59-64389 discloses a two-color effect in which an ink layer consisting of an ink that melts and leaches out when heated and an ink that melts and peels off at a temperature higher than the melting and leaching temperature is provided on a support. A thermal transfer ink sheet is disclosed.

Furthermore, in JP-A-57-15060, an ink layer is provided on a support by dispersing a coloring ink that melts or sublimates at a relatively high temperature in a solid thermal ink that melts or sublimates at a relatively low temperature. A two-color recording and transfer medium is disclosed.

Further, in JP-A-59-13 [1286], a laminated layer is formed on a base material, the lower layer being a high temperature transfer layer containing a hot-melt ink composition, and the upper layer being a low temperature transfer layer containing a leuco dye. a transfer sheet containing a color erasing agent for the leuco dye in the high-temperature transfer layer or interposed as an intermediate layer between the upper layer and the lower layer; and a receiving sheet containing a color developer for the leuco dye. A two-color thermal transfer medium is disclosed.

(Problem to be Solved by the Invention) However, in the above conventional method, the temperature of the ink layer is changed by changing the energy applied to the thermal head in two stages, and multicolor (two-color) recording is possible. In either case, separation of each layer must be achieved only by changing the applied thermal energy, so it is difficult to clearly separate colors unless there is a large difference in melting point between the high-temperature transfer ink material and the low-temperature transfer ink material. becomes. In other words, there is a constraint that a material with a relatively low melting point must be used as an ink material for recording at low temperatures, which causes problems such as background smearing and decreased storage stability. Increasing the melting point of the material requires an even higher melting point of the high temperature transfer ink material. As a result, the thermal energy applied from the thermal head during high-temperature transfer must be extremely large, which tends to reduce the recording speed or destroy the heating element, which is extremely inconvenient in practice.

As a technique for solving the above-mentioned drawbacks, the inventors of the present application have previously proposed Japanese Patent Application Laid-Open No. 61-137789. Patent application 1986-29883
1 proposed a two-color thermal transfer recording method and a two-color thermal transfer recording medium.

In this recording method, at least first and second
The second ink layer can be selectively or , both the first and second ink layers,
This is a method of transferring to a recording medium.

Further, in the thermal transfer material, the magnitude relationship between the adhesive force F1 between the support and the first ink layer and the adhesive force F2 between the first ink layer and the second ink layer is opposite at high temperatures and at low temperatures. It is what it is.

The above-mentioned recording method makes it possible to solve various problems of the conventional heat-sensitive recording method described above, but there is also a second method.
It was desired that only the ink layer should be able to record clearly during transfer.

The present invention solves the drawbacks of the two-color thermal transfer material desired in the prior art, and specifically, the first ink layer is added to the recording obtained by transferring only the second ink layer to the recording paper. To provide a two-color thermal transfer material capable of obtaining clear recording without any color mixing of the layers.

[Means to solve the problem]

The present invention provides a thermal transfer material having at least a thermally transferable first ink layer and a second ink layer on a support in this order, in which the second ink layer is brought into contact with a recording medium and thermal energy is applied from the support side. After applying heat, when the support is peeled from the recording medium, the adhesive force F1 between the support and the first ink layer and the adhesive force F2 between the first ink layer and the second ink layer after applying heat are When F + > F 2, the second ink layer is transferred to the recording medium, and when F, < F2, the first ink layer is transferred to the recording medium.
In a thermal transfer material that transfers the entire ink layer and second ink layer to a recording medium, the first ink layer contains one or two types of
By containing at least one water-soluble resin, transfer recording with excellent print quality without color smearing is possible.

That is, the thermal transfer material of the present invention is a thermal transfer material having a thermally transferable first ink layer and a second thermally transferable ink layer in this order on a support, in which the first ink layer contains one or two water-soluble resins.
It is characterized by containing more than one species.

The present invention will be described in further detail below with reference to the drawings as necessary. In addition, in the following description, "%J" representing the quantitative ratio
and "parts" are based on weight unless otherwise specified.

FIG. 1 is a schematic cross-sectional view in the thickness direction showing the basic structure of the two-color thermal transfer material according to the present invention. The first
Ink layer 3. It has a structure in which second ink layers 4 are sequentially laminated. The first ink layer 3 contains a first dye, and the second ink layer 4 contains a second dye, and each is transferred as a desired image onto a transfer medium by thermal energy during thermal transfer. It will be done. Here, the adhesive force F1 between the support 2 and the first ink layer 3 and the adhesive force F2 between the first ink layer 3 and the second ink layer 4 become F and >F2 in a short period of time immediately after heat application during printing. Transferring only the second ink layer,
After a certain period of time has elapsed after heat application, F<F2, so that both the first ink layer 3 and the second ink layer 4 are transferred.

In the above configuration and relationship, the first ink layer and the second ink layer are separated for a short time immediately after heat application, that is, when F r > F 2, but in this case, the pressing force from the thermal head is Because heat is applied while receiving
There is a risk that the boundary between the ink layer and the second ink layer will become unclear. For this reason, with conventional two-color ribbons, when only the second ink layer is transferred to recording paper, the color tone of the second ink layer becomes a color mixture slightly tinged with the tone of the first ink layer due to the contamination of the first ink layer. . This phenomenon is due to the structure shown in FIG. 2, which more reliably realizes a two-color ribbon, namely the
The same phenomenon can be observed even when the first adhesive layer 5 is provided between the ink layer 3 and the second adhesive layer 6 is provided between the first ink layer 3 and the second ink layer 4.

The present inventors developed a resin material forming the first ink layer in order to prevent the first ink layer from being mixed into the second ink layer at the interface between the first ink layer and the second ink layer. As a result of extensive research, they have discovered that by incorporating one or more types of water-soluble resin into the first ink layer, the phenomenon of contamination at the interface can be effectively prevented. The water-soluble resin has low compatibility with the binders constituting the second ink layer, and even if a relatively large amount of thermal energy is applied (maintained for a certain period of time after applying heat) when transferring the first ink layer, the second ink layer may be Hard to penetrate into the interface of the ink layer. On the other hand, the support and the first
It is necessary to achieve adhesion at the interface between the first ink layer and the second ink layer, and the adhesion at the interface can be adjusted depending on the amount of water-soluble resin used.

That is, when the first ink layer 3 contains these water-soluble resins, the film properties of the first ink layer 3 are improved, and as a result, the second ink layer 4 in the case of FIG. 1 and the second ink layer 4 in the case of FIG. The boundary with the second adhesive layer 6 becomes clear, and mixing into the second ink layer 4 is also prevented.
The recording of the ink layer 4 has no color mixture of the first ink layer 3.
It will be very bright.

The content of water-soluble resin contained in the first ink layer is 0.5
It is preferably in the range of ~20%, more preferably in the range of 1~10%. If the water-soluble resin content is less than 0.5%,
The film properties of the first ink layer 3 do not improve, and mixing into the second ink layer 4 cannot be suppressed. Also, if it exceeds 20%, F
, < When recording at F2, that is, when all layers are transferred, the first
The film properties of the ink layer 3 are too strong, resulting in a poorly sharp recorded image.

As the water-soluble resin to be contained in the first ink layer, polyvinyl alcohol resin, polyvinylpyrrolidone resin, polyester resin, and cellulose resin are preferable because they have excellent film properties, and polyvinyl alcohol resin is particularly preferable. Polyvinyl alcohol resins of 3,170,000 or higher are preferred.

The first layer constituting the thermal transfer layer on the support 2 according to the present invention
The ink layer 3 is made by dispersing the colorant of the first color tone in a binder (this does not mean that it is dissolved), and the second ink layer 4 is made by dispersing the colorant of the second tone in the binder. It becomes dispersed. In addition, as shown in FIG. 2, when an adhesive layer is provided, the first. The second adhesive layer is mainly composed of a binder, but may contain a colorant if necessary.

In order to appropriately set the adhesive force at the interface between the support, the first ink layer, the second ink layer, and if necessary, the first adhesive layer and the second adhesive layer, and the stability between each component,
The components of each layer and the layer thickness forming method may be configured as described below.

The binder used in the first ink layer and the second ink layer according to the present invention, and the binder used in the first ink layer and the second ink layer. Materials used for the second adhesive layer include natural waxes such as spermaceti wax, beeswax, lanolin, carnauba wax, candelilla wax, montan wax, and ceresin wax, petroleum waxes such as paraffin wax and microcrystalline wax, oxidized wax, and ester wax. , low molecular weight polyethylene, synthetic waxes such as Fischer-Tropsch wax, higher fatty acids such as lauric acid, myristic acid, palmitic acid, stearic acid, behenic acid, higher alcohols such as stearyl alcohol and behenyl alcohol, fatty acid esters of sucrose,
Esters such as fatty acid ester of sorbitan, waxes such as amides such as oleylamide: or polyolefin resins, polyamide resins, polyester resins, epoxy resins, polyurethane resins, polyacrylic resins, polyvinyl chloride resins Resin, cellulose resin, polyvinyl alcohol resin, petroleum resin, phenol resin, polystyrene resin, vinyl acetate resin, natural rubber, elastomers such as styrene butadiene rubber, isoprene rubber, chloroprene rubber, polyisobutylene ,
If necessary, 2M or more of resins such as polybdenum are used in combination.

In the thermal transfer material 1 of the present invention, when it is desired to obtain the color tone of the first ink layer 3 and the color tone of the second ink layer 4, a dark color such as black is applied to the first ink layer 3 and a dark color such as black is applied to the second ink layer 4. It is preferable to use a bright color such as yellow for the first ink layer 3.
If you want to obtain a color tone of , and a color mixture of the color tone of the first ink layer 3 and the color tone of the second ink layer 4, for example, if you color the first ink layer 3 yellow and the second ink layer 4 magenta. Magenta and red colors are obtained. In addition, by changing the pigment concentration or layer thickness ratio of each layer, various recordings of two different colors can be obtained.

Colorants include carbon black, nigrosine dye,
Lamp Black, Sudan Black SM, First Yellow 01 Benzidine Yellow, Pigment Yellow, India First Orange, Irgazine Red, Valanitroaniline Red, Toluidine Red, Carmine F
B, Permanent Bordeaux FRR, Pigment Orange R, Lysol Red 20, Lake Red C, Rhodamine F6, Rhodamine B Lake, Methyl Violet B Lake, Phthalocinine Blue, Pigment Blue, Prilliant Green B, Phthalocyanine Green , Oil Yellow GG, Zapon First Niro-CC
G, Kayaset Y963, Kayaset YG, Sumiplast Yellow GG, Zapon First Orange RR,
Known oil scarlet, Sumiblast Orange G, Orazole Brown B, Zapon First Scarlet CG, Eisenspiron Red BEH, Oil Pink OP, Victoria Blue F4R, First Gen Blue 5007, Sudan Blue, Oil Peacock Blue, etc. All dyes and pigments can be used (combining two or more if necessary). In addition, metal powders such as copper powder and aluminum powder, mineral powders such as mica, etc. can be used. Furthermore, as other additives, surfactants, plasticizers, mineral oils, vegetable oil fillers, etc. may be appropriately added to the ink layer or the adhesive layer.

The coloring, that is, the content of the colorant in the first ink layer and the second ink layer, is determined by the first. For each of the second ink layers, 1 to
90%, more preferably a range of 2 to 80%.

Adjust the molecular weight, crystallinity, etc. of the above-mentioned materials as appropriate,
Alternatively, an ink layer or adhesive layer having the above characteristics can be obtained by mixing a plurality of the above materials.

As the support for the thermal transfer material of the present invention, a plastic film of polyester, aramid, nylon, polycarbonate, etc. having a thickness of about 3 μm to 12 μm, or paper such as capacitor paper is used. Excessively thick materials are not preferable because they have poor thermal conductivity. As long as it has high heat resistance and strength, it is also possible to use a thin film with a thickness of 3 μm or less.

In the thermal transfer material of the present invention, the ink layer (
It is desirable that the total thickness (from adhesive layer to adhesive layer) is 20 μm or less. Further, the thickness of each of the first ink layer, the second ink layer, the first adhesive layer, and the second adhesive layer is preferably in the range of 0.5 to 10 μI.

In manufacturing the thermal transfer material of the present invention, the materials constituting each layer may be mixed and coated as an aqueous emulsion using a dispersant such as a surfactant, and can be obtained by commonly used means. Can be done.

In addition, the back side of the support (the side opposite to the ink layer formation side)
It is also effective to provide a layer to supplement heat resistance.

Further, when carrying out a thermal transfer recording method using the thermal transfer material of the present invention, in addition to a thermal head, commonly used heating means such as infrared rays and laser beams can be used as the heating means. In addition, in the case of electrical heating, if necessary, a conductive layer made of a thin film of aluminum or the like is provided between the support and the first ink layer to serve as a return electrode.
Alternatively, the ink may be made conductive.

Next, a two-color printing method using the thermal transfer material of the present invention will be explained.

Specifically, this can be carried out using an apparatus as shown in FIG. Referring to FIG. 3, the thermal transfer material 1 is brought into pressure contact with the recording medium 9 by the thermal head 8 (so that the second ink layer faces the recording medium), and at the same time, the thermal head 8
A pattern of heat is applied to the thermal transfer material 1 from the above. Immediately after this heat application, when the recording medium 9 and the thermal transfer material 1 are separated from each other at the terminal end 8a of the thermal head 8, only the second ink layer is transferred onto the recording medium 9. On the other hand, the peeling control member 10
is moved in the direction of arrow A and placed at the position 10a (dotted line), the recording medium 9 and the thermal transfer material 1 are brought into pressure contact with each other in the same manner as above, and after applying patterned heat with the thermal head 8, they are peeled off. When the control member 10 is peeled off at the position (10a), both the first ink layer and the second ink layer are transferred to the recording medium.

〔Example〕

A transfer test was conducted using the heat-sensitive transfer materials obtained in Examples 1, 2.3 and Comparative Examples shown below by the method described below.

Example 1 Ink (first adhesive layer) Polyethylene oxide aqueous dispersion 70 parts (number average molecular weight 4000) Polyester-polyurethane resin 30 parts Aqueous dispersion (Superflex 300 manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.) The above ink materials were After thorough mixing, a polyethylene terephthalate film (hereinafter abbreviated as PET film) with a thickness of 4.5 μm
After coating and drying, an ink (2) with a thickness of 1 μm was obtained.

<Ink ■ (first ink layer)> Acrylic resin aqueous dispersion 45 parts (Acronal YJ-85010 manufactured by Mitsubishi Yuka Pardish Co., Ltd.) Polyvinyl alcohol resin 5 parts (Gosenol G manufactured by Nippon Gosei Kagaku Kogyo Co., Ltd.) 1-17. Degree of polymerization 1700~+800)
50 parts of carbon black aqueous dispersion The above ink materials were thoroughly mixed and coated on ink (2) to obtain ink (2) with a thickness of 2 μm after drying.

<Ink ■ (Second adhesive layer)> Carnauba wax aqueous dispersion 100 parts (softening point 75°C) The above ink material was coated on ink ■, and after drying, the thickness was 1
A micrometer ink (■) was obtained.

<Ink■ (Second ink layer)) Oxidized polyethylene aqueous dispersion (number average molecular weight 2000) 56 parts Ethylene-vinyl acetate copolymer aqueous dispersion (ethylene content 20%) 24 parts Cyanine blue aqueous dispersion 20 parts After thoroughly mixing the above ink materials, they were coated on ink (1) to obtain ink (2) having a thickness of 2 μm after drying, thereby obtaining a thermal transfer material having the structure shown in FIG. 2.

Example 2 <Ink ■ (first ink layer)> Acrylic resin aqueous dispersion 45 parts (Acronal YJ-85010 manufactured by Mitsubishi Yuka Pardish Co., Ltd.) Polyvinylpyrrolidone resin 5 parts (manufactured by Gokyo Sangyo Co., Ltd. -90) Carbon black water 50 parts of dispersion The above ink materials were thoroughly mixed and coated on ink (2) to obtain ink (2) with a thickness of 2 μm after drying. Further, ink (1) and ink (2) were sequentially applied thereon to obtain a thermal transfer material II having the structure shown in FIG.

Example 3 (Ink ■ (first ink layer)) Acrylic resin aqueous dispersion 45 parts (Acronal YJ-85010 manufactured by Mitsubishi Yuka Pardish Co., Ltd.) Polyvinyl alcohol resin 5 parts (Gosenol GL-05 manufactured by Nippon Gosei Kagaku Kogyo Co., Ltd. Polymerization 500 to 600) carbon black aqueous dispersion 50 parts After thoroughly mixing the above ink materials, coat on top of the ink (2) and dry to a thickness of 2 μm.
Ink ■ was obtained. Furthermore, ink■, ink■
A thermal transfer material (2) having the structure shown in FIG. 2 was obtained.

Comparative example <Ink ■ (first ink layer)> Acrylic resin water dispersion 50 parts (Acronal YJ-85010 manufactured by Mitsubishi Yuka Pardish Co., Ltd.) Carbon black water dispersion $50 parts After thoroughly mixing the above ink materials, apply on top of ink ■ After coating and drying, an ink (2) with a thickness of 2 μl was obtained. Furthermore, ink on top of this
A thermal transfer material (2) shown in FIG. 2 was obtained by sequentially applying ink (2) to the film.

Printing was carried out using the thermal transfer materials I to ① prepared above using the apparatus shown in FIG. 3 under the following conditions. The thermal head used was a 160 dot/1 nch thermal head made by Rohm ■, and the printing energy was 2811 J/+111112.

Further, in this thermal head, the distance from the center of the heating element to the terminal end 8a of the thermal head was 350 μm.

The moving speed of the carriage carrying the thermal head and the thermal transfer material was 50 mIII/sec.

As a result, the time required for each ink layer to peel off rapidly was about 7 m5ec. In addition, the pressure welding means lO for peeling off after a long period of time is provided at the terminal end 8 of the thermal head.
It was attached at a position of about 5IOI11 from a.

Therefore, when peeling was performed after a period of time, the time until peeling was approximately 100 m5ec.

Thermal transfer material I had very good print quality for both black and blue prints. In particular, the blue print was extremely clear with no black color mixture.

Thermal transfer material (■) had very good print quality for both black and blue prints. In particular, the blue print was very clear, although there was a slight black color mixture compared to the thermal transfer material.

Thermal transfer material (■) had very good print quality for both black and blue prints. However, the blue print had a black color mixture compared to the thermal transfer materials I and H, and the blue color was slightly cloudy, but it was at a level that caused no particular problem in practical use.

Thermal transfer material (■) had very good print quality for both black and blue prints. However, the blue print had more black color mixture than that of thermal transfer material M, and was a cloudy blue color.

Comprehensively evaluating the above, the thermal transfer materials were excellent in the following order.

Thermal transfer material 1>H>m>>■ [Effects of the invention] As explained above, by containing a water-soluble resin in the first ink layer and configuring the heat-sensitive transfer material, the second ink color tone is completely free from turbidity due to color mixture. Records can be obtained.

In particular, those using polyvinyl alcohol resin can obtain transferred recorded images of excellent print quality.

The thermal transfer material of the present invention is a transfer material having at least a first ink layer and a second ink layer, and can also be applied to transfer recording of three or more colors.

[Brief explanation of the drawing]

1 and 2 are schematic cross-sectional views in the thickness direction showing the structure of a thermal transfer material. FIG. 3 is an apparatus configuration diagram showing one embodiment of a thermal transfer recording apparatus that performs two-color recording using the thermal transfer material of the present invention. 1...Thermal transfer material 2...Support 3...First ink layer 4...Second ink layer 5...First adhesive layer 6...Second adhesive Layer 8... Thermal head 9... Recorded object 10... Peeling control member 11... Platen 12a... Unwinding core 12b... Winding core 13... Carriage

Claims (1)

[Scope of Claims] 1. A thermal transfer material having at least a thermally transferable first ink layer and a second ink layer in this order on a support, the second ink layer being in contact with a recording medium, and the support side When peeling the support from the recording medium after applying thermal energy from Thermal transfer transfers the second ink layer to the recording medium when the adhesive force F_2 is F_1>F_2, and transfers the entire first ink layer and second ink layer to the recording medium when the adhesive force F_2 is F_1<F_2. 1. A thermal transfer material, wherein the first ink layer contains one or more water-soluble resins. 2. The thermal transfer material according to claim 1, wherein the water-soluble resin is a polyvinyl alcohol resin. 3. The thermal transfer material according to claim 2, wherein the polyvinyl alcohol resin has a polymerization degree of 1500 or more. 4. The thermal transfer material according to claim 1, wherein the water-soluble resin is polyvinylpyrrolidone resin, polyester resin, or cellulose resin.