JPH07149051A - Thermal recording sheet and its production - Google Patents

Abstract

PURPOSE:To provide a high-sensitivity sheet for thermal recording in which the energy of laser beams is efficiently utilized as heat energy necessary for printing. CONSTITUTION:A sheet for thermal recording is constituted by providing a base film 1 and a recording material layer 7 which is formed on the base film 1 and contains a light absorbing substance for absorbing light and converting it into heat and the coloring material. High-heat conductivity fine particles 6 are mixed in the recording material layer 7 and the heat conductivity is regulated to >=1.0W/m.K.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermal recording sheet such as an ink sheet used in a thermal recording apparatus for thermal transfer recording utilizing light energy such as laser energy.

[0002]

2. Description of the Related Art FIG. 9 shows, for example, Japanese Patent Laid-Open No. 62-12878.
FIG. 7 is a cross-sectional view showing the structure of a thermal recording sheet used in a conventional general laser thermal recording apparatus shown in Japanese Patent Publication No.
In the figure, 1 is a transparent base film, and usually polyethylene terephthalate (PET) is used. 2 is a light absorbing layer having a thickness of 2 μm, which contains an infrared absorbing dye such as carbon black or merocyanine dye that absorbs laser light and converts it into heat, and 3 is a heat-melting or heat subliming ink layer, It is the same as that used for ink sheets for various thermal transfer printers. Reference numeral 4 is an image receiving paper, and 5 is a laser beam emitted from a laser light source (not shown) and then condensed and irradiated.

At the time of printing, when the focused laser beam 5 is irradiated from above in FIG. 9, the laser beam 5 passes through the transparent base film 1 and reaches the light absorption layer 2. A portion of the light absorption layer 2 which is exposed to the laser light 5 generates heat, the heat is transmitted to the ink layer 3, and the ink is melted or sublimated, so that the image receiving paper 4
Will be recorded.

That is, the laser thermal recording apparatus uses laser light as a heat source instead of the thermal head used in a general thermal transfer printer. However, in the thermal head, a plurality of heating elements are arranged in a line and a plurality of dots can be printed at the same time. On the other hand, the laser beam can print only one dot at a time, which slows down the printing speed. was there.

Therefore, it is necessary to increase the power of the laser in order to increase the printing speed, but there are limitations such as an increase in cost and an increase in size of the device. Therefore, even if the same laser power is used, the energy efficiency of the thermal recording sheet, that is, the recording sensitivity may be increased. An example of this is the image recording method disclosed in JP-A-3-26595.

FIG. 10 is an explanatory view thereof. The same parts as those in FIG. 9 are designated by the same reference numerals and the description thereof will be omitted. However, in FIG. 10, the image receiving paper 4 needs to be transparent.

In the example of FIG. 10, during operation, laser light 5 is emitted from the transparent image receiving paper 4 side, the laser light 5 passes through the image receiving paper 4 and the ink layer 3, and is converted into heat by the light absorbing layer 2. .
At this time, in the light absorption layer 2, heat is generated mainly on the side on which the laser light 5 strikes (the upper side in FIG. 10), so that the heat is easily transferred to the ink layer 3 and the energy efficiency (recording is higher than that shown in FIG. 9). Sensitivity) is improved.

[0008]

Since the conventional laser thermal recording sheet is constructed as described above, the heat generated in the light absorbing layer 2 is conducted through the ink layer 3 by heat conduction, and the heat of the ink layer 3 is transferred. It is necessary that the side in contact with the image receiving paper 4 reaches a predetermined temperature. At this time, the thermal conductivity of the ink layer 3 is determined by the binder and solvent which are the main components, and the value is 0.1 to 0.
Since it is as low as 3 W / m · K and the efficiency is low, there is a problem that the printing speed becomes slow.

Further, in the example of Japanese Patent Laid-Open No. 3-26595, the heat conduction in the ink layer 3 is similar, and there is a problem that only the transparent image receiving paper 4 can be used.

The present invention has been made to solve the above problems, and provides a high-sensitivity thermal recording sheet capable of efficiently utilizing the energy of laser light as the thermal energy required for printing, and a method for producing the same. The purpose is to get.

[0011]

A thermal recording sheet according to claim 1 of the present invention comprises a base film, a light absorbing substance which is formed on the base film and absorbs light to convert it into heat, and a coloring material. And a recording material layer containing the same. The recording material layer contains fine particles having a high thermal conductivity and has a thermal conductivity of 1.0.
W / m · K or higher.

According to a second aspect of the present invention, there is provided a thermal recording sheet in which the recording material layer includes a light absorbing layer containing a light absorbing substance which absorbs light and converts it into heat, and a coloring formed on the light absorbing layer. The material and the ink layer containing fine particles having high thermal conductivity are separately formed.

A thermal recording sheet according to a third aspect of the present invention is a recording comprising a base film, a base film, a light absorbing substance that absorbs light and converts it into heat, and a coloring material. A material layer, and the content ratio of the light absorbing substance in the recording material layer is high on the base film side and low on the opposite side.

A thermal recording sheet according to a fourth aspect of the present invention has a base film and an ink layer formed on the base film and containing a coloring material, and the base film absorbs light to generate heat. A light absorbing substance to be converted is mixed in, and the content ratio of this light absorbing substance is high on the ink layer side and low on the opposite side.

According to a fifth aspect of the present invention, in the thermal recording sheet, the layer containing the light absorbing substance has a light absorption rate of 85 to 95% with respect to the wavelength of light used.

A thermal recording sheet according to claim 6 of the present invention has a base film and an ink layer formed on the base film and containing a coloring material, and absorbs light and converts it into heat. In the base film or on the base film, and an antireflection film for preventing light reflection is provided on the surface irradiated with light.

According to a seventh aspect of the present invention, there is provided a thermal recording sheet comprising a base film, a light absorbing layer which is formed on the base film and contains a light absorbing substance which absorbs light and converts it into heat, and the light absorbing layer. An ink layer containing a colorant formed thereon, an antireflection film provided on a surface irradiated with light to prevent reflection of light, the content ratio of the light absorbing substance is high on the ink layer side, and Lower base film on the other side, 85-95% light absorption for the wavelength of light used
And an ink layer containing fine particles having a high thermal conductivity and having a thermal conductivity of 1.0 W / m · K or more.

According to a eighth aspect of the present invention, there is provided a method of manufacturing a thermal recording sheet, which comprises applying a coloring material and a pre-charged light absorbing substance on a base film to a predetermined thickness, or in the process of applying the coloring material and the light absorbing substance. By passing an electric field through the recording material layer consisting of the coloring material and the light absorbing substance and the base film, the content ratio of the light absorbing substance in the recording material layer is high on the base film side and low on the opposite side. And then dried.

[0019]

In the thermal recording sheet according to the first aspect of the present invention, the heat generated in the recording material layer is efficiently transmitted to the entire thickness direction of the recording material layer by the fine particles having high thermal conductivity, and The transfer of the coloring material therein is efficiently performed.

In the thermal recording sheet according to the second aspect of the present invention, the heat generated in the light absorbing layer is efficiently transmitted to the entire thickness direction of the ink layer by the fine particles having high thermal conductivity, and the heat in the ink layer is reduced. The coloring material is efficiently transferred.

In the thermal recording sheet according to the third aspect of the present invention, since the light absorbing substance and the coloring material are mixed in the recording material layer, light absorption, that is, heat generation is performed in the immediate vicinity of the coloring material. Further, since the opposite side of the base film, that is, the image receiving paper side has less light absorbing substance (more coloring material), the transfer of the coloring material to the image receiving paper side, that is, the transfer, is not disturbed by the light absorbing substance and smoothly. Done.

In the thermal recording sheet according to the fourth aspect of the present invention, light absorption, that is, heat generation occurs near the ink layer in the base film, and this heat is quickly conducted to the ink layer.

In the thermal recording sheet according to the fifth aspect of the present invention, the layer containing the light absorbing substance has a light absorptivity of 85 to 95% with respect to the wavelength of the light used. If 100% of the transmitted light is reflected by the image receiving paper and enters the layer containing the light absorbing material again, the wasted light is transmitted again 2.25% to 0.25% ((15%) ² ~
(5%) ² ) Very small.

In the thermal recording sheet according to the sixth aspect of the present invention, the light which is reflected by the surface of the thermal recording sheet and wasted is reduced by the antireflection film on the light irradiation surface.

In the thermal recording sheet according to claim 7 of the present invention, an antireflection film provided on a surface irradiated with light for preventing reflection of light, and a content ratio of the light absorbing substance in the ink layer side are Higher and lower on the opposite side, the base film has a light absorption rate of 85-95 for the wavelength of light used.
% Of the light absorption layer, and fine particles having a high thermal conductivity are mixed to have at least two of the respective functions of the ink layer having a thermal conductivity of 1.0 W / m · K or more.

In the method of manufacturing a thermal recording sheet according to the eighth aspect of the present invention, after the colorant and the pre-charged light absorbing substance are applied to the base film to a constant thickness,
Alternatively, in the coating process, the recording material layer composed of the coloring material and the light absorbing material and the base film pass an electric field, so that the content ratio of the light absorbing material in the recording material layer is the base film side. Higher on the other side and lower on the other side, then dried.

[0027]

【Example】

Example 1. FIG. 1 is a sectional view showing the structure of a thermal recording sheet showing an embodiment of the present invention. In FIG. 1, 1
Is a base film having a thickness of 6 μm and a thermal conductivity of about 0.1 W / m · K, and PET is used as in the conventional case. 7 is a recording material layer containing a sublimable dye and a merocyanine dye in a solvent such as toluene or methyl ethyl ketone and a binder agent such as polyvinyl butyral. The recording material layer 7 has a thermal conductivity of about 200 W / m. Fine particles 6 of K are mixed in to have a thermal conductivity of about 50 W / m · K. Aluminum powder is used as the fine particles 6. Further, the sublimable dye plays a role of coloring the transferred image, and the merocyanine dye plays a role of absorbing laser light. Reference numeral 4 is an image receiving paper, and 5 is a condensed laser beam.

Next, the printing process will be described. When the focused laser beam 5 is emitted, it passes through the base film 1 and reaches the recording material layer 7. Recording material layer 7
The laser light 5 is absorbed by the merocyanine-based dye contained therein to generate heat. The heat heats the entire recording material layer 7, and the sublimable dye in the recording material layer 7 is transferred to the surface of the image receiving paper 4 by thermal diffusion and transferred. At this time, the thermal conductivity of the base film 1 is about 0.1 W / m · K. The thermal conductivity of the recording material layer 7 is usually about 0.3 W / m.
・ K, but about 50W by mixing fine particles 6
/ M · K. Therefore, since the heat generated in the recording material layer 7 is quickly conducted in the entire thickness direction of the recording material layer, the transfer of the ink to the image receiving paper 4 is performed more efficiently than before.

In Example 1, the thermal conductivity of the recording material layer 7 was set to 50 W / mK, but according to the examination result, the thermal conductivity of the recording material layer 7 is 1.0 W / m. m ・ K
With the above, the heat generated in the recording material layer 7 is generated.
Conducted quickly in the entire thickness direction, improving efficiency.
Further, the fine particles 6 may be iron powder, ceramic powder, or the like, and has the same effect as that of the first embodiment.

Example 2. FIG. 2 is a sectional view showing the structure of a thermal recording sheet showing an embodiment of the present invention. Figure 2
In the above, 2 is a light absorbing layer having a thickness of 2 μm, which contains carbon black which absorbs light and converts it into heat in the resinous binder agent. Reference numeral 3a is a thermally sublimable ink layer composed of a coloring material, a binder agent, etc., and the thermal conductivity of the ink layer 3a is about 2 or less.
The fine particles 6 of 00W / mK are mixed and the thermal conductivity is about 50.
W / m · K. Aluminum powder is used as the fine particles 6. 1, 4 and 5 are the same as those in FIG.

Next, the printing process will be described. When the focused laser light 5 is emitted, it passes through the base film 1 and reaches the light absorption layer 2. Laser light here 5
The light-absorbing layer 2 in the area irradiated with is heated, and this heat is conducted to the base film 1 side and the ink layer 3a side. At this time, the thermal conductivity of the base film 1 is about 0.1 W / m.
K. Further, the thermal conductivity of the ink layer 3a is normally about 0.3 W / m · K, but it becomes about 50 W / m · K by mixing the fine particles 6. Therefore, most of the heat generated in the light absorbing layer 2 is conducted to the ink layer 3a, and also in the ink layer 3a, the heat is easily conducted to the image receiving paper 4 which is important for the transfer, Since the temperature rises quickly, the transfer of ink to the image receiving paper 4 is performed more efficiently than before.

In Example 2, the thermal conductivity of the ink layer 3a was set to 50 W / mK, but according to the examination result, the thermal conductivity of the ink layer 3a is 1.0 W / mK. K
With the above, the heat generated in the light absorption layer 2 is quickly conducted throughout the thickness direction of the ink layer 3a, and the efficiency is improved. Further, in the second embodiment, the case of the heat sublimation ink is shown, but the heat melting ink may be used. Furthermore, fine particles 6
For example, iron powder or ceramic powder may be used.
Has the same effect as.

Example 3. FIG. 3 is a sectional view showing the structure of a thermal recording sheet showing an embodiment of the present invention. Figure 3
7a is a recording material layer, which is composed of a sublimable dye and carbon black 8 in a solvent such as toluene or methyl ethyl ketone and a binder agent such as polyvinyl butyral.
Is included. Here, the sublimable dye plays a role of coloring the transferred image, and the carbon black 8 plays a role of absorbing laser light. 1, 4 and 5 are the same as those in FIG.

Here, in the recording material layer 7a, the carbon black 8 has a high content rate on the side in contact with the base film 1 and is gradually reduced toward the side in contact with the image receiving paper 4. .

Next, the printing process will be described. When the focused laser beam 5 is emitted, it passes through the base film 1 and reaches the recording material layer 7a. The laser light 5 is absorbed by the carbon black 8 in the recording material layer 7a to generate heat. This heat heats the entire recording material layer 7a, and the sublimable dye in the recording material layer 7a is transferred to the surface of the image receiving paper 4 by thermal diffusion and transferred. At this time, the carbon black 8 is transferred to the image receiving paper 4 in the recording material layer 7a.
Although the content rate gradually decreases toward the side in contact with, the heat transfer efficiency of the generated heat is good because it is dispersed in almost the entire area. Also,
The carbon black 8 is the image receiving paper 4 in the recording material layer 7a.
Since there is only a small number of sides contacting with, the transfer of the sublimable dye toward the image receiving paper 4 is not hindered.

Although the content of the carbon black 8 in the recording material layer 7a is gradually changed in the layer thickness direction in the third embodiment, it may be changed stepwise.
In FIG. 3, the upper half of the recording material layer 7a may include the carbon black 8 and the lower half may not include the carbon black 8. In this last example, from the viewpoint of thermal efficiency, it is the same as the one in which the light absorption layer 2 and the ink layer 3 shown in the conventional example are separated, but it is said that one coating step is required for manufacturing the thermal recording sheet. effective.

Example 4. FIG. 4 is a sectional view showing the structure of a thermal recording sheet showing an embodiment of the present invention. Figure 4
1a is a base film having a thickness of about 10 μm, and the lower half contains carbon black 8 that absorbs light and converts it into heat. Reference numeral 3 is a thermally sublimable ink layer made of a coloring material, a binder agent and the like. Reference numerals 4 and 5 are the same as those in FIG.

At the time of printing, the laser light 5 is absorbed by the carbon black 8 in the base film 1a to generate heat. Since the carbon black 8 exists under the base film 1a, that is, on the side close to the ink layer 3, the heat generated in the base film 1a is quickly conducted to the adjacent ink layer 3, and the entire ink layer 3 is heated. . Next, the sublimable dye of the ink layer 3 is transferred to the surface of the image receiving paper 4 by thermal diffusion and transferred.

Further, in the fourth embodiment, the case of the heat sublimation ink is shown, but the heat melting ink may be used. Further, although the case where the carbon black 8 is contained only in the lower half of the base film 1a is shown, the content ratio of the carbon black 8 may gradually increase toward the ink layer 3 side. 8 may be included only in the lower side of the base film 1a having a thickness of about 1 to 3 μm.

Example 5. FIG. 5 is a sectional view showing the structure of a thermal recording sheet showing an embodiment of the present invention. Figure 5
In the above, 1 is a base film having a thickness of 6 μm, and 2a is a light absorbing layer containing carbon black that absorbs light and converts it into heat in the resinous binder agent. The content ratios of the carbon black and the binder agent in the light absorption layer 2a are the same as in the conventional case. In addition, for laser light having a wavelength of 770 to 830 nm,
A conventional light absorption layer having a light absorption rate of about 100% has a thickness of 2
However, the thickness of the light absorption layer 2a is set to 0.67 μm, which is ⅓ of the conventional value, which gives a light absorption rate of 85%. 3,
Reference numerals 4 and 5 are the same as those in FIG.

At the time of printing, transfer is performed by the same process as in the second embodiment. At this time, the wavelength of the laser beam 5 is set to 780
In nm, about 15% of light passes through the light absorption layer 2a. This light further passes through the ink layer 3 and is reflected and absorbed by the surface of the image receiving paper 4. If the surface of the image receiving paper 4 is 1
If it is reflected by 00%, this light is again absorbed by 12.75% by the light absorption layer 2a having an absorptance of 85%. Therefore, 97.75% will be effectively used. Further, if absorption occurs on the surface of the image receiving paper 4, it becomes heat and is used for printing, so that the effective rate is further increased.

Although heat is generated in the light absorption layer 2a, it naturally consumes heat for raising the temperature of the layer itself, so that a heat capacity as small as possible, that is, a thin layer is desirable. In the fifth embodiment, the thickness is optimized in consideration of the round trip path of light, so that the thermal efficiency is very good.

Although the light absorption rate is set to 85% in the fifth embodiment, any value may be used as long as it is between 85% and 95%.
If it is less than 85%, there will be wasted light that is transmitted, and
If it is 5% or more, the layer becomes too thick and the efficiency becomes poor.

Example 6. FIG. 6 is a sectional view showing the structure of a thermal recording sheet showing an embodiment of the present invention. Figure 6
In the above, since 1 to 5 are the same as those of the conventional example shown in FIG. Reference numeral 9 denotes an antireflection film for preventing reflection of light. In Example 6, magnesium fluoride MgF ₂ vapor-deposited to a thickness of 150 nm is used.

Here, the wavelength of the laser beam 5 is λ = 780n
If m, the refractive index n _b ≈1.7 of the base film 1 made of PET and the refractive index n _m ≈1.3 of the vapor deposition film of MgF ₂

[0046]

[Equation 1]

[0047] satisfied, further, when the thickness of the MgF ₂ which is h, in order to satisfy n _m h = λ / 4, the reflection when the laser beam 5 is incident on the base film 1 is minimized.
That is, the energy of the laser beam 5 can be used for printing without waste, and the efficiency of the thermal recording sheet is improved. The process in which the ink is heated and melted or sublimated to transfer the ink is the same as in the conventional example. Although the antireflection film is provided on the conventional thermal recording sheet in Example 6, the antireflection film may be provided on the thermal recording sheets shown in Examples 1 to 5.

Example 7. The antireflection film 9 described in Example 6 was used as an antireflection film for preventing reflection of light, the base film 1a described in Example 4 was used as a base film, and the light absorption layer containing a light absorbing substance that absorbs light and converts it into heat. The thermal recording sheet may be configured to include any two or more of the light absorbing layer 2a described in Example 5 and the ink layer 3a described in Example 2 as an ink layer containing a coloring material.

Example 8. FIG. 7 is an explanatory view illustrating a method of manufacturing a thermal recording sheet showing an embodiment of the present invention.
In FIG. 7, 1 is a base film, and 7 is a recording material layer in which the content ratio of carbon black 8 as a laser light absorbing substance is high on the base film 1 side and low on the opposite side. Numerals 11 and 12 are rollers, and numeral 13 is an ink reservoir for containing the solution ink 14 and the carbon black 8. Reference numeral 16 is a DC power supply. In addition, carbon black 8
Also, the roller 11 is positively charged.

Next, the manufacturing process will be described. The ink 14 and the carbon black 8 flowing out from the gap of the ink reservoir 13 are applied to the periphery of the roller 11 in a substantially constant thickness. Here, the roller 11 is positively charged, and the carbon black 8 which is also positively charged is mixed in the ink 14 evenly. Therefore, the carbon black 8 is formed on the recording material layer 7 by electrostatic force on the roller 11. Many are distributed on the outer side, that is, on the opposite side of the roller 11. Next, the base film 1 is fed to the left in the drawing and the ink 14
The carbon black 8 is applied and then dried. At this time, a large amount of carbon black 8 is distributed on the base film 1 side, so that the thermal recording sheet shown in Example 3 is obtained.

Example 9. FIG. 8 is an explanatory view illustrating a method of manufacturing a thermal recording sheet showing an embodiment of the present invention.
In FIG. 8, 15 is an electrode and 16 is a DC power supply. Others are the same as those shown in FIG. 7, and therefore, the same reference numerals are given and the description thereof is omitted. However, in this Example 9, the carbon black 8 is negatively charged and the roller 11 is not charged. The electrode 15 has − on the recording material layer 7 side and + on the base film 1 side. Next, the manufacturing process will be described. Ink 1 flowing out from the gap of the ink reservoir 13
4 and carbon black 8 are applied to the periphery of the roller 11 in a substantially constant thickness. After the ink 14 and the carbon black 8 are applied to the base film 1, before being dried, the ink is passed through the electric field created by the electrode 15. In this Example 9, the carbon black 8 is negatively charged. Then, during passage of the electric field, the negatively charged carbon black 8 is largely distributed to the + electrode side, that is, the base film 1 side due to the electrostatic force, and the thermal recording sheet shown in Example 3 is obtained.

[0052]

According to the first aspect of the present invention, since fine particles having a high thermal conductivity are mixed in the recording material layer, the heat generated in the recording material layer is quickly conducted in the entire thickness direction of the recording material layer. The light having the same intensity can be printed at a higher speed, or the light having the same printing speed can be recorded at a lower optical power.

According to the second aspect of the present invention, since the fine particles having a high thermal conductivity are mixed in the ink layer, the heat generated in the light absorbing layer is quickly conducted in the entire thickness direction of the ink layer and has the same strength. With the above light, printing can be performed at a higher speed, or with the same printing speed, recording can be performed with a lower optical power.

According to the third aspect of the present invention, since the light absorbing substance and the coloring material are mixed, light absorption, that is, heat generation is performed in the immediate vicinity of the coloring material, so that the efficiency is high. Further, since the image receiving paper side has less light absorbing substance (more coloring material), the transfer of the coloring material to the image receiving paper side, that is, the transfer is smoothly performed without being disturbed by the light absorbing substance. The recording sensitivity of the use sheet is improved.

According to the fourth aspect of the present invention, since the light absorption rate on the ink layer side is high in the base film, heat is generated near the ink layer, and this heat is quickly transmitted to the ink layer. Because of conduction, the recording sensitivity of the thermal recording sheet is improved.

According to the fifth aspect of the present invention, the light absorptivity is 85 to 95% as compared with the case where the layer containing the light absorptive substance is made of the same material and the light absorptivity is almost 100%. Since it is configured, the layer containing the light absorbing substance can be remarkably thin, and the laser light is hardly wasted, so that the recording sensitivity of the thermal recording sheet is improved.

According to the sixth aspect of the invention, since the antireflection film is provided on the light irradiation surface, the wasteful laser light reflected by the surface of the thermal recording sheet is reduced, and the recording sensitivity of the thermal recording sheet is reduced. Is improved.

According to the invention of claim 7, the antireflection film according to claim 6, the base film according to claim 4 and the claim 5
Since it has any two or more of the respective functions of the light absorbing layer described above and the ink layer described in claim 2, it has a synergistic effect of the effect of the invention of each claim, and the recording sensitivity of the thermal recording sheet is high. Further improve.

According to the eighth aspect of the invention, since the component ratio of the light absorbing substance in the thickness direction of the recording material layer is controlled by the electrostatic force, a thermal recording sheet having good recording sensitivity can be easily manufactured. it can.

[Brief description of drawings]

FIG. 1 is a cross-sectional configuration diagram showing the structure of a thermal recording sheet in Example 1 of the present invention.

FIG. 2 is a cross-sectional configuration diagram showing the structure of a thermal recording sheet in Example 2 of the present invention.

FIG. 3 is a sectional configuration diagram showing the structure of a thermal recording sheet in Example 3 of the present invention.

FIG. 4 is a sectional configuration diagram showing a structure of a thermal recording sheet according to Example 4 of the present invention.

FIG. 5 is a sectional configuration diagram showing the structure of a thermal recording sheet in Example 5 of the present invention.

FIG. 6 is a sectional configuration diagram showing the structure of a thermal recording sheet in Example 6 of the present invention.

FIG. 7 is an explanatory diagram illustrating a method of manufacturing a thermal recording sheet according to Example 8 of the present invention.

FIG. 8 is an explanatory diagram illustrating a method of manufacturing a thermal recording sheet according to Example 9 of the present invention.

FIG. 9 is a cross-sectional configuration diagram showing a structure of a conventional thermal recording sheet.

FIG. 10 is an explanatory diagram illustrating a structure of a conventional thermal recording sheet and a method of using the sheet.

[Explanation of symbols]

 1a Base film 2a Light absorption layer 3a Ink layer 4 Image receiving paper 5 Laser light 6 Fine particles 7 Recording material layer 8 Carbon black 9 Antireflection film 11, 12 Roller 13 Ink reservoir 14 Ink 15 Electrode 16 DC power supply

Claims (8)

[Claims] 1. A thermal recording system using a light as a heat source, comprising a base film and a recording material layer formed on the base film and containing a light absorbing substance that absorbs light and converts it into heat, and a coloring material. The thermal recording sheet used is characterized in that the recording material layer is mixed with fine particles having a high thermal conductivity to have a thermal conductivity of 1.0 W / m · K or more. 2. The recording material layer includes a light absorbing layer containing a light absorbing substance that absorbs light and converts it into heat, and an ink layer formed on the light absorbing layer and containing a coloring material and fine particles having high thermal conductivity. The thermal recording sheet according to claim 1, wherein the thermal recording sheet is formed separately from the sheet. 3. A thermal recording system using a light as a heat source, which comprises a base film and a recording material layer formed on the base film and containing a light absorbing substance that absorbs light and converts it into heat, and a coloring material. The thermal recording sheet used is characterized in that the content ratio of the light absorbing substance in the recording material layer is high on the base film side and low on the opposite side. 4. A thermal recording sheet having a base film and an ink layer formed on the base film and containing a coloring material, which is used in a thermal recording system using light as a heat source. A heat-recording sheet, characterized in that a light-absorbing substance that absorbs heat and is converted into heat is mixed, and the content ratio of the light-absorbing substance is high on the ink layer side and low on the opposite side. 5. The thermal recording according to claim 1, wherein the layer containing the light absorbing material has a light absorption rate of 85 to 95% with respect to a wavelength of light used. Sheet. 6. A base film, and an ink layer formed on the base film and containing a colorant, and containing a light absorbing substance for absorbing light and converting it into heat, in or on the base film, A thermal recording sheet used in a thermal recording system using light as a heat source, characterized in that an antireflection film for preventing light reflection is provided on a surface irradiated with light. 7. A base film, a light absorbing layer formed on the base film and containing a light absorbing substance that absorbs light and converts it into heat, and an ink layer formed on the light absorbing layer and containing a coloring material. In a thermal recording sheet having a light source as a heat source for use in a thermal recording method, an antireflection film provided on a surface irradiated with light to prevent reflection of light, and a content ratio of the light absorbing substance to the ink layer The base film is high on the side and low on the opposite side, the light absorption layer has a light absorption rate of 85 to 95% with respect to the wavelength of light used, and the heat conductivity is 1.0 W by mixing fine particles having high heat conductivity. / M · K or more, any two or more ink layers having a thermal recording sheet. 8. A recording material layer containing the coloring material and the light absorbing material, and the base, after the coloring material and the pre-charged light absorbing material are applied to the base film to a certain thickness or in the process of application. 4. An electric field is passed through the film to increase the content ratio of the light-absorbing substance in the recording material layer on the base film side and on the opposite side, and then the film is dried. Method of manufacturing thermal recording sheet.