JPH0665516B2 - Thermal transfer recording medium and thermal transfer recording method - Google Patents

Description

The present invention relates to a heat-sensitive transfer two-color recording medium and a heat-sensitive transfer recording method for transferring a two-color recording image onto a recording medium.

[Conventional technology]

In addition to the general features of the heat-sensitive recording method that the device used is light and compact, has no noise, and is excellent in operability and maintainability, the heat-sensitive transfer recording method does not require color-type processed paper, and It has the feature of being excellent in the durability of images, and has recently come into wide use.

This heat-sensitive transfer recording method generally uses a heat-sensitive transfer material obtained by applying a heat-transferable ink having a colorant dispersed in a heat-meltable binder on a sheet-shaped support, The ink layer is superposed on the recording medium so that it is in contact with the recording medium, and heat is supplied from the support side of the heat-sensitive transfer material by the thermal head to transfer the melted ink layer to the recording medium. To form a transferred ink image.

In addition, there are strong market demands for obtaining two-color printing while making the most of the advantages of the thermal transfer recording method, and various techniques for obtaining two-color printing have been proposed.

Conventionally, as a method of two-color printing on a plain paper by using a thermal transfer recording method, JP-A-56-148591 discloses two heat-meltable high-melting ink layers containing different colorants on a substrate. A and the low melting point ink layer B are sequentially laminated from the base material side, only the low melting point ink layer B is transferred onto the plain paper in the case of low heat application energy, and the heat melting ink layer A in the case of high heat application energy, A two-color type thermal transfer recording element is disclosed in which both B are transferred to obtain a two-color recording.

Further, in JP-A-59-64389, a two-color heat-sensitive transfer ink is provided with an ink layer comprising an ink melted and leached by heating on a base material and an ink melted and peeled off at a temperature higher than the melt-leached temperature. A sheet is disclosed.

In these methods, the energy applied to the thermal head is changed in two steps to change the temperature of the ink layer and perform two-color printing. However, when high energy is applied to the ink layer to raise the temperature, a relatively low temperature portion is generated around the high temperature portion due to the diffusion of heat, so that the low temperature printing is performed around the high temperature portion. Edges of color will occur. Furthermore, when high energy is applied to the thermal head, it takes a relatively long time for the temperature to drop, which causes a drawback that the tail of the color printed at low temperature is likely to occur behind the part printed at high temperature. Have.

Further, in any of the methods, there is a restriction that a material having a relatively low melting point must be used as a material for ink printed at low temperature, which causes problems such as soiling and deterioration of storability.

[Problems to be solved by the invention]

The object of the present invention is to eliminate the above-mentioned drawbacks of the conventional two-color printing method, and it is possible to obtain beautiful printing with different color tones on plain paper by a simple method, and a thermal transfer recording medium. The present invention provides a heat-sensitive transfer recording medium and a heat-sensitive transfer recording method which are free from the restriction that an ink made of a low melting point material which is apt to cause defects in storage stability and the like must be used.

[Means for solving problems]

The heat-sensitive transfer recording medium according to the present invention has at least two heat-sensitive transferable ink layers, a first ink layer and a second ink layer, on a support, and between the both ink layers or the first ink layer and the support. An adhesive layer is provided on at least one of the body and the adhesive force between the second ink layer and the first ink layer at a high temperature is smaller than the adhesive force between the first ink layer and the support, and the temperature is low. At times, the adhesive force between the second ink layer and the first ink layer is greater than the adhesive force between the first ink layer and the support.

Further, a heat-sensitive transfer recording method capable of performing multicolor recording using the heat-sensitive transfer recording medium according to the present invention is such that the heat-sensitive transfer recording medium is brought into contact with a recording medium, and thermal energy is transferred to the heat-sensitive transfer recording medium according to recording information. After the application, the separation time from the application to the separation of the thermal transfer recording medium and the recording medium is controlled depending on whether the separation time is short or long, and the second ink layer is transferred to the recording medium with the short separation time. However, both layers of the two ink layers are transferred to the recording medium with the long separation time.

That is, the thermal transfer recording medium of the present invention applies thermal energy to the thermal transfer recording medium, separates the thermal transfer recording medium from the recording medium in a short time after applying thermal energy, and applies thermal energy. After that, the two-color recording is made possible by appropriately providing a process of cooling the heat-sensitive transfer medium to separate the heat-sensitive transfer recording medium from the recording medium.

Hereinafter, the present invention will be described in more detail with reference to the drawings as necessary. In the following description, “%” and “part” representing the quantitative ratio are based on weight unless otherwise specified.

FIG. 1 is a schematic cross-sectional view in the thickness direction showing an example of the thermal transfer recording medium of the present invention. That is, it is a schematic cross-sectional view in the thickness direction shown in FIG. That is, the thermal transfer material 5 shown in FIG.
The first ink layer 2, the adhesive layer 3, and the second ink layer 4 are sequentially formed on the support 1.

The thermal transfer recording medium of the present invention comprises a first ink layer 2 and a second ink layer 2.
It is necessary that the magnitude relationship between the adhesive force between the ink layers 4 and the adhesive force between the first ink layer 2 and the support 1 be opposite at high temperature and at low temperature. For example, when heat is applied to the thermal transfer recording medium of the present invention, immediately after heating, the separation between the first ink layer 2 and the second ink layer 4 is more than the separation between the first ink layer 2 and the support 1. Good, and when the time from the heating to the separation of the support 1 from the recording medium is long, that is, the thermal transfer recording medium 5
The recording medium and the recording medium are in close contact with each other, and the first ink layer 2 is easily peeled from the support 1 when the thermal head is run and the thermal transfer material is cooled while being in close contact after heat is applied. To configure.

The characteristics between the above layers will be described with reference to FIG.
In the present invention, the magnitude of the adhesive force between the second ink layer and the first ink layer and the adhesive force between the first ink layer and the support direction are substantially determined when transfer recording is performed on the recording medium. Second
It specifies that the latter adhesive force is greater when the ink layers are transferred, and the former adhesive force is substantially greater when both ink layers are transferred. When peeled from the recording medium and transferred to the recording medium, the form of peeling of the ink layer (for example, whether the peeling position is a strict boundary surface between the second ink layer and the first ink layer, an adhesive layer The degree of residual heat transfer recording medium after transfer, etc.) is not considered in the evaluation of adhesive strength.

The adhesive force between the first ink layer 2 and the second ink layer 4 and the adhesive force between the first ink layer 2 and the support 1 change with heating or cooling. In the example shown in FIG. 1, as the adhesive layer 3, one having a large change in adhesive force with temperature is used, and the adhesive force sharply decreases as the temperature is increased by being heated by the thermal head. Therefore, the adhesive force between the first ink layer 2 and the second ink layer 4 is smaller than the adhesive force between the first ink layer 2 and the support 1 in a state immediately after being heated and before the temperature decreases. become weak. Therefore, immediately after the second ink layer 4 adheres to the recording medium by heating, that is, when the recording medium and the thermal transfer recording medium are separated from each other at time t ₁ in FIG. 4A, only the second ink layer 4 is removed. Transcribed. Further, when the temperature of the ink layer decreases with time, the adhesive force between the first ink layer 2 and the second ink layer 4 recovers, and the adhesive force causes the adhesive force between the first ink layer 2 and the support 1. after it exceeded the force, the first ink layer 2 together with the second ink layer 4 if pulled away in other words the time t ₂ is also transferred. Therefore,
If the color tones of the first ink layer 2 and the second ink layer 4 are changed in the thermal transfer recording medium of the present invention, two-color recording can be obtained by the thermal transfer recording medium of the present invention. When it is desired to obtain the color tone of the first ink layer 2 and the color tone of the second ink layer 4, the first ink layer 2
A dark color such as black, and the second ink layer 4 includes a first color such as red.
It is better to arrange a lighter color than the ink layer. Also,
By setting the first ink layer and the second ink layer to colors of similar colors, it is possible to perform recording of two shades of light and shade. Also,
When the first ink layer is a layer containing a white pigment or the like having a large hiding effect, the first ink layer can act as a correction ink layer.

Further, each layer of the thermal transfer recording medium shown in FIG. 1 can be configured as follows. That is, immediately after heating, the separation between the first ink layer 2 and the support 1 is better than the separation between the first ink layer 2 and the second ink layer 4, and the support 1 is separated from the recording medium by heating. When it takes a long time,
The second ink layer 4 is configured to be easily separated from the first ink layer 2. The characteristics between the respective layers in this case are shown in FIG. 4 (b). Immediately after heating the thermal transfer recording medium, the adhesive force between the support 1 and the first ink layer 2 is the same as that of the first ink layer 2. It becomes weaker than the adhesive force between the second ink layers 4. Further, when the temperature of the thermal transfer recording medium lowers with time, the adhesive force between the support 1 and the first ink layer 2 is restored, and the adhesive force of the first ink layer 2 and the second ink layer 4 is restored. Exceeds the adhesive strength between.

In the example shown in FIG. 1, the first ink layer 2 has a large change in adhesive strength with temperature, and the adhesive layer 3 has a relatively small change in adhesive strength with temperature.
Therefore, when the thermal transfer recording medium is separated from the recording medium at time t ₁ , both the first ink layer 2 and the second ink layer 4 are transferred, and when separated at time t ₂ , the second ink layer 4 is formed.
Only transcribed.

4 (a) and 4 (b), the adhesive strength between the layers is described as being restored to the state before the start of heating after a lapse of time after heating, but the adhesive force is not always before the start of heating. There is no need to recover to the state of. For example, as shown in FIG. 4 (c), the adhesive force does not become opposite before the heating is started, and the adhesive force may become opposite during the cooling period after heating. When the ink layer emulsion is applied and formed, the state before the start of heating and the state after a lapse of time after heating may be different. Further, when the first ink layer 2 is peeled from the support 1, the first ink layer 2 is not always necessary.
It is not necessary to peel at the interface between the substrate and the support 1, and it may be separated in the first ink layer 2.

FIG. 2 is a schematic cross-sectional view in the thickness direction showing another example of the thermal transfer recording medium of the present invention. The thermal transfer recording medium shown in FIG. 2 has a first adhesive layer 10, a first ink layer 2, a second adhesive layer 3 and a second ink layer 4 in this order on a support 1.

Also in the case of the thermal transfer recording medium shown in FIG. 2, the relationship between the adhesive force between the support 1 and the first ink layer 2 and the adhesive force between the first ink layer 2 and the second ink layer 4 is There is no difference from the thermal transfer recording medium shown in FIG. That is, when the second adhesive layer 3 having a large change in adhesive force with temperature is used, the temperature of the second adhesive layer 3 rises due to the heating of the thermal head, and the strength of the second adhesive layer 3 sharply decreases. The adhesive force between the layers changes as shown in FIG. 4 (a). If the first adhesive layer 10 having a large change in the adhesive force with temperature is used and the second adhesive layer 3 having a relatively small change in the adhesive force with temperature is used, the adhesive force between the respective layers is shown in FIG.
It shows the changes shown in (b).

FIG. 3 is a schematic sectional view in the thickness direction showing still another example of the thermal transfer recording medium of the present invention. That is, the thermal transfer recording medium shown in FIG. 3 has an adhesive layer 11, a first ink layer 2 and a second ink layer 4 on a support 1 in order.

Also in the case of the thermal transfer recording medium shown in FIG. 3, the relationship between the adhesive force between the support 1 and the first ink layer 2 and the adhesive force between the first ink layer 2 and the second ink layer 4 is There is no difference from the thermal transfer recording medium shown in FIG. That is, when the second ink layer 4 whose adhesive strength to the first ink layer greatly changes with temperature is used, the temperature of the second ink layer 4 rises due to the heating of the thermal head and the strength of the second ink layer 4 increases. The adhesive force between layers decreases sharply as shown in Fig. 4.
Shows changes like (a). In addition, as the adhesive layer 11, one having a large change in adhesive force depending on temperature is used, and the second ink layer 4
If the change in the adhesive force to the first ink layer is relatively small depending on the temperature, the adhesive force between the respective layers will be as shown in FIG.
It shows the changes shown in (b).

As the support 1 of the thermal transfer recording medium of the present invention, a film having a thickness of about 3 μm to 12 μm, such as polyester, aramid, nylon, polycarbonate, or condenser paper, can be used. An excessively thick one is inferior in thermal conductivity, which is not preferable. It is also possible to use a thin film of 3 μm or less as long as it has high heat resistance and strength.

The second ink layer 4 of the thermal transfer recording medium shown in FIGS. 1 to 3 contains 1% to 50% of a coloring agent and has a softening temperature of 60 ° C.
It is preferably about 180 ° C. The second ink layer 4 having a softening temperature lower than 60 ° C. is not very preferable in terms of storage stability. Further, those having a softening temperature higher than 180 ° C. are not very preferable in terms of sensitivity to heat. Further, the colorant contained in the first ink layer 2 of the thermal transfer recording medium shown in FIGS. 1 to 3 is contained in 90% of the first ink layer 2 in the case of FIG. 4 (a). However, 1 to 80% is preferable, and 1 to 5% in the case of FIG. 4 (b).
0% is preferable.

The thermal transfer recording medium shown in FIG. 1 will be described below.

When each layer has the characteristics shown in FIG. 4 (a), the first ink layer 2 is generally preferably a heat-meltable one, and may have an adhesive property at room temperature, and has an extremely high softening temperature. Those that do not melt may be used. On the other hand, the adhesive layer 3 has a softening temperature of 6 in the case of FIG. 4 (a).
Those of 0 ° C to 180 ° C are generally preferred.

The softening temperature referred to in the present invention means the Shimadzu Flow Tester CF.
It is determined as the outflow starting temperature when the apparent viscosity-temperature curve of the sample ink is determined using a T500 type under the conditions of a temperature increase rate of 10 kg and a temperature increase rate of 2 ° C./min.

In the case of FIG. 4 (a), regarding the adhesive layer 3 and the second ink layer 4, the melt viscosity as a layer material including additives and the like at a temperature 30 ° C. higher than the melting temperature thereof (by a rotational viscometer) ) Is preferably 1,000,000 cps or less and 10 cps or more, and especially the second ink layer 4 has a melt viscosity at the above temperature of 20 in order to maintain the adhesive strength to paper.
It is better to choose 0cps or more. Further, it is desirable that the melt viscosity of the adhesive layer 3 is lower than the melt viscosity of the second ink layer 4 at a temperature higher by 30 ° C. than the softening temperature of the second ink layer 4.
As a result, when peeling at time t ₁ in FIG. 4 (a),
A good image can be obtained with less separation in the second ink layer 4.

When the thermal transfer medium is separated from the recording medium at the time t ₁ in FIG. 4 (a), only the second ink layer 4 is transferred to the transfer target, and the softening temperature of the adhesive layer 3 is set to the second ink. It is desirable to choose to be equal to or below the softening temperature of layer 4. When printing is performed with the thermal head, the temperature of the thermal head is in a printing state and a non-printing state at the end portion of the printing portion in the thermal head advancing direction, but at that time, the strength of the adhesive layer 3 remains relatively high and the second ink layer 4 remains. May adhere to the recording medium, and the first ink layer 2 may be transferred together with the second ink layer 4. Is the softening temperature of the adhesive layer 3 equal to the softening temperature of the second ink layer 4 as described above? Alternatively, by selecting a value lower than that, such a phenomenon can be prevented.

In the case of FIG. 4 (b), it is sufficient to use the first ink layer 2 and the adhesive layer 3 in which the above characteristics are reversed.

The thermal transfer recording medium shown in FIG. 2 will be described below.

In general, the first ink layer 2 is preferably a heat-melting one, and may have an adhesive property at room temperature, or may have an extremely high softening temperature. However, a material such as an inorganic pigment layer that does not melt may be used as long as it can be transferred. The coloring agent may be contained in an amount of 1% to 90%. Also,
The first ink layer 2 may be composed of a layer composed of only a colorant such as steam.

When each layer has the characteristics shown in FIG. 4 (a), the first adhesive layer 10 having the same characteristics as the above-mentioned characteristics of the first ink layer 2 can be used. However, the first adhesive layer 10 does not need to contain a coloring agent. The second adhesive layer 3 having a softening temperature of 60 ° C. to 180 ° C. is generally suitable.

In the case of FIG. 4 (a), regarding the second adhesive layer 3 and the second ink layer 4, the melt viscosity (rotational viscosity) as a layer material including additives at a temperature 30 ° C. higher than the softening temperature of each. (Based on the total) is preferably 1,000,000 cps or less and 10 cps or more. In particular, the second ink layer 4 has a melt viscosity at the above temperature in order to maintain the adhesive strength to paper.
It is better to choose at least 200 cps. Furthermore, the melt viscosity of the second adhesive layer 3 is. It is desirable that the melt viscosity of the second ink layer 4 is lower than the melt viscosity of the second ink layer 4 at a temperature higher by 30 ° C. than the softening temperature of the second ink layer 4. As a result, when peeling at time t ₁ in FIG. 4 (a), there is less separation in the second ink layer 4,
A good image can be obtained.

When the thermal transfer recording medium is peeled from the recording medium at the time t ₁ in FIG. 4 (a), only the second ink layer 4 is transferred to the recording medium. 2 It is desirable to select the softening temperature equal to or lower than the softening temperature of the ink layer 4. When printing with the thermal head, the temperature of the thermal head is in a printing state and a non-printing state at the end of the printing portion in the thermal head advancing direction, but at that time, the strength of the second adhesive layer 3 remains relatively high and the second ink Although the layer 4 may adhere to the recording medium and the first ink layer 2 may be transferred together with the second ink layer 4, as described above, the softening temperature of the second adhesive layer 3 is set to the softening temperature of the second ink layer 4. By selecting the temperature equal to or lower than the temperature, such a phenomenon can be prevented.

In the case of FIG. 4 (b), it is sufficient to use the first adhesive layer 10 and the second adhesive layer 3 having the above-mentioned characteristics reversed.

The thermal transfer recording medium shown in FIG. 3 will be described below.

Generally, the first ink layer 2 is preferably a heat-melting one, and may have a tackiness at room temperature, or may have a very high softening temperature. However, a material such as an inorganic pigment layer that does not melt may be used as long as it can be transferred. Coloring agents may be included in the range of 1% to 90%. Further, the first ink layer 2 may be composed of a layer made of only a colorant by vapor deposition or the like.

If each layer has the characteristics shown in FIG. 4 (a), the adhesive layer 1
The material having the same characteristics as those of the first ink layer 2 can be used for 1 However, the adhesive layer 11 need not contain a colorant.

For the second ink layer 4, the softening temperature of each layer is 30
Melt viscosity (by rotational viscometer) as a layer material including additives at a temperature of ℃ higher than 1,000,000cps, 10
It is better to select it so that it is cps or more, and especially considering the adhesive force to paper, it is good to select the melt viscosity to be 200 cps or more.

In the case of FIG. 4B, the adhesive layer 11 having the same characteristics as those of the second ink layer 2 may be used.

In the heat-sensitive transfer recording medium of the present invention, the total ink layer on the support 1 (including the adhesive layer, that is, the portion other than the support 1) is preferably 20 μm or less. 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 μm.

It is desirable to use an incompatible material as the material of the first ink layer 2 and the second ink layer 4. Although the adhesive layer 3 is provided between the first ink layer 2 and the second ink layer 4, the adhesive layer 3 is crushed by the pressure of the thermal head, and the first ink layer 2 and the second ink layer are partially formed. 4 may come into contact with each other, and by selecting an incompatible material as described above, the separation of the two colors becomes good.

In addition, it is also effective to provide a layer for supplementing heat resistance on the back surface of the support 1 or between the support 1 and the first ink layer 2. Further, it is also effective to provide a layer on the second ink layer 4 for increasing the adhesive force to the recording medium. In addition, various functional layers can be appropriately provided between the layers or on the surface. The functional layer may contain a coloring agent. As an effective aspect of the functional layer containing the colorant, an ink layer exhibiting transferability when receiving heat energy higher than those of the first ink layer and the second ink layer is used as the functional layer, and the first and second inks are used. After the transfer of the layer, the color tone of the functional layer can be imparted to the recording medium by applying higher heat energy, if necessary. Further, the same effect can be expected by using an ink layer exhibiting transferability by applying pressure instead of high heat energy as a functional layer.

Further, in carrying out the thermal transfer recording method, the heating means may be a commonly used heating means such as an infrared ray or a laser beam in addition to a thermal head, and in the case of energization heating, if necessary, the first ink may be used. A conductive thin layer such as aluminum is provided between the layer and the support to form a return electrode.

The first ink layer 2, the second ink layer 4, and the adhesive layer 3 can be used by individually or appropriately mixing the binders described below, and further by adding a colorant and other additives as necessary. As the binder, whale wax, beeswax, lanolin, carnauba wax, candelilla wax, montan wax, natural wax such as selein wax, paraffin wax, petroleum wax such as microcrystalline wax, ester wax, low molecular weight polyethylene, Fischer-Tropsch wax Synthetic wax such as lauric acid, myristic acid, palmitic acid, stearic acid, behenic acid and other higher fatty acids, stearyl alcohol, behenyl alcohol and other higher alcohols, sucrose fatty acid ester, sorbitan fatty acid ester and other esters, oleylamide Homopolymers of amides such as styrene, polystyrene, poly-p-chlorostyrene, polyvinyltoluene and the like and substituted products thereof; styrene-p-chlorostyrene copolymers Styrene - propylene copolymer, styrene - vinyltoluene copolymer,
Styrene-vinyl naphthalene copolymer, styrene-methyl acrylate copolymer, styrene-ethyl acrylate copolymer, styrene-butyl acrylate copolymer, styrene-octyl acrylate copolymer, styrene-methyl methacrylate copolymer Polymer, styrene-ethyl methacrylate copolymer, styrene-butyl methacrylate copolymer, styrene-α-chloromethyl methacrylate copolymer, styrene-vinyl methyl ether copolymer, styrene-vinyl ethyl ether copolymer , Styrene-vinyl methyl ketone copolymer, styrene-butadiene copolymer, styrene-isoprene copolymer, styrene, styrene-acrylonitrile-indene copolymer, styrene-maleic acid copolymer, styrene-maleic acid ester copolymer Styrene-based copolymerization such as coalescence Or polymethylmethacrylate, polybutylmethacrylate, polyvinyl chloride, polyvinyl acetate, polyethylene, ethylene-vinyl acetate copolymer, ethylene-acrylic acid copolymer, polypropylene, polyester, polyurethane, polyamide, epoxy resin, polyvinyl Butyral, Polyamide, Polyacrylic acid resin, Rosin, Modified rosin, Terpene resin,
Phenolic resin, aliphatic or alicyclic hydrocarbon resin, aromatic petroleum resin, polyethylene, polypropylene, polyisobutylene, polyethylene wax, polyethylene oxide, polytetrafluoroethylene, ethylene-acrylic acid copolymer, ethylene-acrylic acid Ethyl copolymer, ethylene-
A thermoplastic resin made of an olefin homopolymer such as vinyl acetate copolymer or a copolymer thereof or a derivative thereof is used.

In addition, as a colorant, carbon black, nigrosine dye, lamp black, Sudan black SM, alkali blue,
First Yellow G, Benzidine Yellow, Pigment Yellow, India First Orange, Irgadine
Red, Paranitroaniline Red, Toluidine Red, Carmine FB, Permanent Bordeaux FRR, Pigment Orange R, Resor Red 20, Rake Red C, Rhodamine FB, Rhodamine B Lake, Methyl
Violet B Rake, Phthalocyanine Blue, Pigment Blue, Brilliant Green B, Phthalocyanine Green, Oil Yellow GG, Savon First Yellow CGG, Kayaset Y963, Kayaset YG, Sumiplast Yellow GG, Pomelo First Orange RR, Oil.
Scarlet, Sumiplast Orange G, Orazol
All known dyes and pigments such as brown B, pomelo first scarlet GG, aisenspiron red BEH, oil pink OP, Victoria blue F4R, fast gen blue 5007, sudan blue, and oil peacock blue can be used. Further, as the colorant, copper powder, metal powder such as aluminum powder, or mineral powder such as mica can be used. Other plasticizers, mineral oils, vegetable oils and the like can also be added as additives.

The molecular weight of the above materials, the crystallinity and the like can be adjusted appropriately,
Alternatively, a plurality of the above materials can be mixed to obtain an ink layer or an adhesive layer having the characteristics shown in FIG. 4 (a) or 4 (b).

In producing the heat-sensitive transfer recording medium of the present invention, the material constituting each layer described above, for example, methyl ethyl ketone,
An organic solvent capable of dissolving a binder such as xylene or tetrahydrofuran may be mixed to prepare a coating solution, and each layer may be sequentially coated.

Further, so-called hot melt coating may be performed in a molten state by heating and melting after mixing the materials constituting each layer.

Further, a dispersant such as a surfactant may be added to the materials forming each layer to form an aqueous emulsion, which may be mixed and applied. Also, it is possible to apply each layer by using these methods.

Now, the thermal transfer recording method of the present invention using the thermal transfer recording medium will be described below. In addition, the case where the most typical thermal head is used as a heat source will be described below. In the following description, as an example of the heat-sensitive transfer recording medium, a heat-sensitive medium having the structure shown in FIG. 1 and having the characteristics shown in FIG.

FIG. 5 is a schematic cross-sectional view in the thickness direction of the thermal transfer recording medium showing an outline of the case of transferring the second ink layer 4. In FIG. 5, 5 is a thermal transfer recording medium, 6 is a thermal head, 6a is a heat generating portion of the thermal head, 7 is a recording medium, and 8 is a recording medium.
Indicates a platen.

Now, the case where the first ink layer 2 is black and the second ink layer 4 is red will be described. FIG. 5 shows after recording, the thermal head 6 moves to the right and the thermal transfer recording medium 5 is wound up on a reel (not shown), and the thermal transfer recording medium 5 is transferred from the recording medium 7 to the thermal head 6 and the heater. The state of being peeled off immediately after passing through the portion 6a is shown. Immediately after peeling, Fig. 4
This corresponds to the time t ₁ in (a). As a result, a red recording 4a is obtained on the recording medium 7.

FIG. 6 is a schematic cross-sectional view in the thickness direction of the thermal transfer recording medium showing an outline of the case where both the first ink layer 2 and the second ink layer 4 are transferred. The difference from the example shown in FIG. 5 is that after the heat-sensitive transfer recording medium 5 is heated, the recording medium 7 and the heat-sensitive transfer recording medium 5 are idled for a certain distance and then peeled off. This is the point that the pressing member 9 is provided for the purpose. The member 9 is provided, for example, on a carriage (not shown). The member 9 is configured to move in conjunction with the thermal head 6 while maintaining a certain distance, and to move back and forth as necessary. That is, when the member 9 is retracted, the thermal transfer recording medium 5 is separated from the recording medium 7 immediately after the thermal head 6 has passed, as shown in FIG. On the other hand, when the member 9 projects forward, as shown in FIG. 6, the thermal transfer recording medium 5 and the recording medium 7 are brought into close contact with each other even after the thermal head 6 has passed, and the thermal transfer recording medium 5 is not heated. The time from the application of energy to the peeling of the thermal transfer recording medium 5 becomes long.

FIG. 6 shows a state after recording, in which the thermal transfer recording medium 5 is wound up on a reel (not shown) while the head 6 travels to the right after heat is applied, and the thermal transfer is performed immediately after the member 9. It is shown that the recording medium 5 and the recording medium 7 are peeled off, both the first ink layer 2 and the second ink layer 3 are transferred, and black recording 2a is obtained on the recording medium 7.

In the thermal transfer recording method described above, there is no difference even if a thermal transfer recording medium having the characteristics shown in FIG. 4 (b) is used. However, in this case, if the thermal transfer recording medium is peeled from the recording medium immediately after being heated by the thermal head, both the first ink layer 2 and the second ink layer 4 are transferred to the recording medium, and after a short time after heating. Second if peeled
The ink layer 4 is transferred to the transfer medium.

As described above, according to the present invention, two-color printing can be selected by simply changing the time until the thermal transfer recording medium is peeled off after printing, and beautiful printing can be performed on plain paper or the like. You can In particular, in the transfer medium of the present invention having an adhesive layer between the first ink layer and the second ink layer, when the first and second ink layers are peeled from the support, they can be peeled by the adhesive layer, The ink layer can be transferred as a layer. Therefore, beautiful printing with less blurring can be obtained even on paper with a relatively low smoothness. In the transfer medium of the present invention having an adhesive layer between the first ink layer and the support, the first ink layer can be transferred as a layer onto the second ink layer, so that the hiding power of the first ink layer is high. Is strong and beautiful in terms of its color tone.

Hereinafter, the present invention will be described more specifically with reference to examples.

In the present invention, the number average molecular weight of polyethylene oxide was measured by the following measuring method.

[Molecular weight measurement method]

By VOP (Vapor Pressure Osmometry Method) method, for example, using benzene as a solvent, polyethylene oxide is added at 0.2 to 1.0 g /
The concentration (C) was dissolved in 100 ml benzene at several different concentrations, the osmotic pressure (π / c) of each was measured, and the concentration C-osmotic pressure π / c is plotted. Osmotic pressure (π / c) at infinite dilution. Read from this plot, (π / c). The number average molecular weight ▲ ▼ is obtained from the calculation formula of RT / ▲ ▼.

Example 1 <Ink 1> Ink 1 was prepared by thoroughly mixing the components of the above formulation. A polyethylene terephthalate film support having a thickness of 6 μm (hereinafter referred to as PET) was used and dried at 70 ° C. to form a first ink layer having a thickness of 2 μm.

<Ink 2> The ink 2 is applied on the first ink layer previously provided,
The water was evaporated at 80 ° C. to form an adhesive layer of carnauba wax having a thickness of 1 μm.

<Ink 3> Ink 3 was prepared by thoroughly mixing the components of the above formulation, and the ink was applied onto the previously provided adhesive layer and dried at 70 ° C. to a thickness of 2
A second ink layer having a thickness of μm was formed to obtain a thermal transfer recording medium (I) having the structure shown in FIG.

Example 2 <Ink 4> After forming the first ink layer and the adhesive layer in the same manner as in Example 1, the ink 4 is applied onto the adhesive layer and dried at 80 ° C. to obtain a thickness of 2
A second ink layer having a thickness of μm was formed to obtain a thermal transfer recording medium (II) having the structure shown in FIG.

Example 3 <Ink 5> <Ink 6> 100 parts of aqueous polyethylene oxide dispersion (number average molecular weight 5,000, softening temperature 140 ° C., particle diameter 1 μm) Inks 5 and 6 were prepared by thoroughly mixing the components of the above formulation.

In the same manner as in Example 1, the first ink having a thickness of 2 μm was formed using the ink 5.
The ink layer was formed of the ink 6 to form an adhesive layer having a thickness of 2 μm, and the ink 3 was formed to form a second ink layer having a thickness of 2 μm. The thermal transfer recording medium (III) having the structure shown in FIG.
Got

Example 4 <Ink 7> (The above ratios are solid content ratios) Ink 7 was prepared by thoroughly mixing the components of the above formulation. Addition type silicone resin for release paper 0.3g / m ² back coated, 70
Using a 3.5 μm PFT film support that has been dried by heating at ℃ to form a heat-resistant protective layer, apply Ink 7 on the side opposite to the heat-resistant protective layer and dry at 70 ℃ to provide a first adhesive layer with a thickness of 1.5 μm. It was

<Ink 8> (The above ratios are solid content ratios) Ink 8 was prepared by thoroughly mixing the components of the above formulation. Ink 8 was applied onto the first adhesive layer previously provided, and water was evaporated at 80 ° C. to form a first ink layer having a thickness of 2.5 μm.

<Ink 9> Ink 9 was prepared by thoroughly mixing the components of the above formulation, and the ink 9 was applied onto the first ink layer previously provided to evaporate water at 80 ° C. to form a second adhesive layer having a thickness of 1.5 μm. .

<Ink 10> (The above ratios are solid content ratios) The components of the above formulation are thoroughly mixed to prepare the ink 10, and the ink 10 is applied on the second adhesive layer provided in advance to evaporate the water at 80 ° C. to have a thickness of 2 μm. A second ink layer was formed to obtain a thermal transfer recording medium (IV) having the constitution shown in FIG.

Example 5 <Ink 11> (The above ratio is the solid content ratio) <Ink 12> (The above ratios are solid content ratios) Inks 11 and 12 were prepared by thoroughly mixing the components of the above formulation.

Ink 7, Ink 11, Ink 9 and Ink 12 were sequentially applied onto PET having a thickness of 6 μm and dried in the same manner as in Example 4 to obtain a thermal transfer recording medium (V) having the structure shown in FIG. .

Example 6 <Ink 13> <Ink 14> <Ink 15> Ink 13, Ink 14 and Ink 15 were prepared by thoroughly mixing the components of the above formulation. Ink 13, Ink 14, Ink 15 and Ink 10 were sequentially coated on 3.5 μm PET which had been subjected to the interface treatment in the same manner as in Example 4 and dried to obtain a thermal transfer recording medium (VI).

Example 7 <Ink 16> (The above ratio is the solid content ratio) <Ink 17> (The above ratio is the solid content ratio) <Ink 18> (The above ratios are solid content ratios) Inks 16, 17, and 18 were prepared by thoroughly mixing the components of the above formulation. Addition type silicone resin for release paper 0.3g / m ² backside coating, heat-dried at 70 ℃ to form heat resistant protective layer 3.5μm
Ink 16, Ink 17 and Ink 18 are sequentially applied and dried on the side opposite to the heat resistant protective layer using the PET film support of
A first adhesive layer having a thickness of 15 μm, a first ink layer having a thickness of 2 μm, and a second ink layer having a thickness of 2 μm were formed to obtain a thermal transfer recording medium (VII) having the structure shown in FIG.

Example 8 <Ink 19> <Ink 20> <Ink 21> Ink 9, Ink 20, and Ink 21 were sequentially applied and dried in the same manner as in Example 7 to obtain a thermal transfer recording medium (VIII) having the structure shown in FIG.

The thermal transfer recording media (I) to (V
Using III), printing was performed using a type star 6 manufactured by Canon Inc. The thermal head used was a Rohm HUD. In this thermal head, the distance from the center of the heat generating part to the thermal head end 6b (see Fig. 3) is 35
It was 0 μ. The moving speed of the carriage equipped with the thermal head and interribbon is 50 nm / sec. Therefore, when rapidly peeling (time t _{1 in} FIG. 4), the time until peeling is about 7 msec. Further, the pressure contact means 9 for peeling with time is attached at a position about 5 mm from the terminal end 6b of the thermal head. Therefore, when peeling was delayed (time t _{2 in} FIG. 4), the time until peeling was about 100 msec. Even if the position of the pressure contact means was changed from the end of the thermal head to 2 mm to 20 mm, the printing result did not change.

When printing was performed on plain paper using the thermal transfer recording media (I) and (IV), a blue print was produced when rapidly peeled off.
When it was peeled off after a while, a black print was obtained. The blue print of the thermal transfer recording medium (I) showed very slight black spots, but was sufficiently good for practical use.

When printing on plain paper using the thermal transfer recording media (II), (V) and (VII), blue print is obtained when rapidly peeled, and black print is obtained when peeled off after a while. It was The blue print was beautiful with almost no black spots.

When printing was performed on plain paper using the thermal transfer recording media (IV), (VI) and (VIII), black print was obtained when rapidly peeled, and blue print was obtained when peeled off after a while. . The blue print was good although very slight black spots were seen.

[Brief description of drawings]

FIGS. 1, 2 and 3 are schematic cross-sectional views in the thickness direction showing an example of the thermal transfer recording medium of the present invention, FIG. 4 (a) and FIG.
(b) and FIG. 4 (c) are graphs showing the relationship between the lapse of time and the change in the adhesive force between the layers, and FIG. Sectional view,
FIG. 6 is a sectional view showing a state in which the heat-sensitive transfer recording medium of the present invention is peeled from the recording medium after a predetermined time has elapsed after heating. 1 ... Support, 2 ... First ink layer, 3 ... Adhesive layer, 4 ... Second ink layer, 5 ... Thermal transfer recording medium, 6 ... Thermal head, 7 ... Recording medium, 8 ...... Platen.

 ─────────────────────────────────────────────────── ─── Continued front page (72) Inventor Nao Yaegashi 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Inventor Shuzo Kaneko 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon (72) Inventor Naoki Kushida 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Inventor Koichi Taima 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. ( 72) Inventor Takeyuki Suzuki 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (56) References JP 59-165690 (JP, A) JP 59-96992 (JP, A) JP 60-54893 (JP, A) JP 60-236788 (JP, A) JP 55-12396 (JP, A) JP 56-148591 (JP, A) JP 57-53391 (JP, A) Open Akira 59-64389 (JP, A) JP Akira 59-59493 (JP, A)

Claims (2)

[Claims] 1. A support having at least two heat transferable ink layers, a first ink layer and a second ink layer, between the two ink layers or between the first ink layer and the support. An adhesive layer is provided on at least one of the spaces, and the adhesive force between the second ink layer and the first ink layer at high temperature is smaller than the adhesive force between the first ink layer and the support, and at low temperature. Is a thermal transfer recording medium characterized in that the adhesive force between the second ink layer and the first ink layer is greater than the adhesive force between the first ink layer and the support. 2. A support having at least two heat transferable ink layers, a first ink layer and a second ink layer, between the two ink layers or between the first ink layer and the support. A thermal transfer recording medium having an adhesive layer on at least one of the intervals is brought into contact with the recording medium, heat energy is applied to the thermal transfer recording medium according to the recording information, and after the application, the thermal transfer recording medium and the recording medium are applied. The separation time until the separation with the recording medium is controlled depending on whether the separation time is short or long, the second ink layer is transferred to the recording medium with the short separation time, and the two ink layers are separated with the long separation time. A thermal transfer recording method characterized by transferring both layers to a recording medium.