JPH0624131A - Method of making reversible thermal recording material transparent and image recording device - Google Patents

Abstract

PURPOSE:To provide a method for making a reversible thermal recording material transparent and an image recording device, in which a change into a transparent state is enabled in a short time, manufacturing cost is reduced in a manufacturing process and a high-contrast image, which is erased completely, can be formed at the time of the recording of the image. CONSTITUTION:A reversible thermal recording material, in which a heat- sensitive layer, which mainly comprises a resin matrix and an organic low molecular substance dispersed into the resin matrix and transparency of which reversibly changes while depending upon a temperature, is formed onto a support, is heated at a transparent-changing temperature, and cooled at a temperature from 30 deg.C to 45 deg.C, thus changing the reversible thermal recording material transparent.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for making a reversible thermosensitive recording material transparent by which writing and erasing of information can be repeated by heating, and a reversible thermosensitive film using the reversible thermosensitive recording material. TECHNICAL FIELD The present invention relates to a transparent method for a card or a card, and an image recording apparatus for recording an image by the transparent method.

[0002]

2. Description of the Related Art In recent years, rewritable materials have been demanded as thermal recording materials in order to save paper resources. As the most influential material, one having a heat-sensitive layer in which an organic low molecular weight substance such as a higher alcohol and a higher fatty acid is dispersed in a resin such as polyester on a support is disclosed in, for example, Japanese Patent Laid-Open Publication No. Sho 5 (1999) -58242.
It is known in Japanese Patent Laid-Open No. 4-119377 and Japanese Patent Laid-Open No. 55-154198. Recording with this type of reversible heat-sensitive recording material, that is, image formation and erasing is based on the change in transparency depending on the temperature of the heat-sensitive layer. It has the characteristic that it can be erased.

[0003]

However, this reversible thermosensitive recording material has a problem that it does not become transparent at the time of production and image recording due to the influence of environmental conditions and the like, and as a result, during the production process, The re-processing of the transparency process increases the manufacturing cost. Further, there was a defect of defective erasing during image recording.

The object of the present invention is to solve the above-mentioned drawbacks, to enable transparency in a short time, to reduce the manufacturing cost in the manufacturing process, and to form a high-contrast image without erasing defects during image recording. It is an object of the present invention to provide a method for making a reversible heat-sensitive recording material transparent, and an image recording apparatus to which the method is applied.

[0005]

Means for Solving the Problems As a result of repeated studies on the phenomenon of poor transparency, the present inventors have found that the graph of FIG.
This phenomenon tends to cause defective transparency as the cooling temperature after heating is lower than the clearing temperature in the clearing step. Particularly, when the cooling temperature after heating to the clearing temperature is lower than 30 ° C., the transparency is remarkably high. The present invention has been accomplished by finding that the transparency becomes worse and that the transparency is inferior in the vicinity of 1 second after cooling to a temperature higher than 45 ° C. after heating to the transparency temperature.

The invention according to claim 1 of the present invention comprises, as a main component, a resin base material and an organic low molecular weight substance dispersed in the resin base material on a support, and the transparency is reversible depending on temperature. In a method of making a reversible thermosensitive recording material having a thermosensitive layer that changes in a variable manner, the reversible thermosensitive recording material is heated to a clearing temperature and then cooled to a temperature of 30 ° C. or higher and 45 ° C. or lower. .

The invention according to claim 2 of the present invention is
After heating to the clearing temperature of claim 1, 30 seconds after 10 seconds
It is characterized in that it is cooled to a temperature of not less than 0 ° C and not more than 45 ° C.

Further, in the invention according to claim 3 of the present invention, the resin base material and the organic low-molecular substance dispersed in the resin base material are main components on the support, and the transparency depends on the temperature. A heating means for heating the reversible thermosensitive recording material provided with a thermosensitive layer whose temperature changes reversibly, and a cooling means for controlling the reversible thermosensitive recording material to a temperature of 30 ° C. or higher and 40 ° C. or lower after the heating. It is characterized by having.

The present invention will be described in more detail below. The reversible thermosensitive recording material of the present invention utilizes the transparency change (transparent state, cloudy opaque state) as described above, and the difference between the transparent state and the cloudy opaque state is presumed as follows.

That is, (i) in the case of being transparent, the particles of the organic low molecular weight substance dispersed in the resin base material are composed of large particles of the organic low molecular weight substance, and the light incident from one side is scattered. It appears to be transparent because it is transmitted to the other side without any effect. (Ii) In the case of white turbidity, the particles of the organic low molecular weight substance are composed of polycrystals of fine crystals of the organic low molecular weight substance. Since the crystal axes of are oriented in various directions, the light incident from one side is refracted many times at the crystal interface of the organic low-molecular substance particles and is scattered and thus appears white.

In FIG. 1 (representing the change in transparency due to heat), a thermosensitive layer mainly composed of a resin base material and an organic low molecular weight substance dispersed in the resin base material is, for example, T
It is cloudy and opaque at room temperature below ₀ . This is the temperature T
_When it is heated to ₂ , it becomes transparent, and even if it is returned to room temperature below T ₀ again in this state, it remains transparent. It is considered that this is because the organic low molecular weight substance is in a semi-molten state from the temperature T ₂ to T ₀ or lower and the crystal grows from the polycrystal to the single crystal. Upon further heating to T ₃ or more temperature becomes translucent state intermediate between the maximum transparency and the maximum opacity. Next, when this temperature is lowered, the first cloudy opaque state is restored without taking the transparent state again. It is considered that this is because when the organic low molecular weight substance is melted at a temperature of T ₃ or higher, the polycrystal is deposited by being cooled. When this opaque state is heated to a temperature between T _{1 and} T ₂ and then cooled to room temperature, that is, a temperature of T ₀ or lower, an intermediate state between transparent and opaque can be obtained. In addition, if the transparent material at room temperature is heated to a temperature of T ₃ or higher and then returned to room temperature,
It returns to cloudy and opaque state again. That is, both opaque and transparent forms at room temperature and intermediate forms thereof can be obtained.

Therefore, the heat sensitive layer can be selectively heated by selectively applying heat to form a cloudy image on a transparent background and a transparent image on a cloudy background, and the change can be repeated many times. It is possible.

The reason for the present invention is inferred from the mechanism of transparency-whitening of the reversible thermosensitive recording material. After heating to the clearing temperature, the difference in transparency due to the difference in cooling method is that the organic low molecular weight substance in the heat sensitive layer has a difference in the crystal structure of the organic low molecular weight substance during the heating-cooling process, that is, the process of melting-solidification. It is considered that the difference occurred in the transparency. Specifically, when heated to a clearing temperature and then cooled at a low temperature, that is, when cooled under a rapid cooling condition, a crystal grows in a short time during the process in which the molten organic low-molecular-weight substance in the heat-sensitive layer solidifies, and is close to a polycrystalline structure. It is considered that the transparency deteriorates because the crystals grow and precipitate.
On the contrary, it is considered that when the material is cooled at a high temperature, that is, under slow cooling conditions, the growth of the crystal of the organic low molecular weight substance melted in the heat sensitive layer is suppressed and the crystal is deposited as a single crystal structure to improve the transparency.

The graph of FIG. 2 shows the relationship between the cooling method after heating to the clearing temperature and the transparency. Those heated to the clearing temperature and then cooled at a temperature of less than 30 ° C. are transparent even after being cooled for a long time. The transparency is low, and the one cooled at a temperature higher than 45 ° C. has a low transparency value in a short time. This is due to variations in transparency during the manufacturing process or erasing defects during image recording. Can occur. Therefore, the cooling condition for obtaining stable transparency is 10 after heating at the clearing temperature.
It is desirable to cool to a temperature of 30 ° C. or higher and 45 ° C. or lower in seconds or less.

An image recording apparatus for realizing the present invention is shown in FIG.
It shows in (a)-(c). It is a repeatable image recording apparatus in which the reversible thermosensitive recording material 2 is heated to the clearing temperature by the erasing device 5 and then cooled and erased by the cooling device 4, and the following three cooling systems are proposed. Figure 3 (a)
Shows an image recording device equipped with a cooling roll, and FIG.
FIG. 3B shows an image recording apparatus equipped with a cooling plate, and FIG.
(C) shows a schematic configuration of an image recording apparatus provided with a cool air generating means as a cooling device. Water or alcohol or the like is used as the refrigerant in FIGS. 3A and 3B, and the cooling temperature of each device can be arbitrarily changed. Further, the cooling device of FIG. 3 (c) has a weak cooling effect because it is non-contact,
Therefore, the air volume control is a device that can be changed arbitrarily. Further, in order to make the cooling efficiency more stable, it is desirable to apply cold air from above and below.

Next, a manufacturing apparatus for realizing the present invention is shown in FIG.
It shows in (a)-(c). A resin base material and a coating material containing an organic low-molecular substance dispersed in the resin base material as a main component are applied on a support by a coating head 6, heated in the first drying box 7 to a clouding temperature, and then clouded. And then heated to the clearing temperature in the second drying box 8 to cool the cooling device 4.
The following three methods are proposed as a cooling device for cooling and making transparent by means of the above, and cooling equipment for making transparent. Figure 4
FIG. 4A shows a manufacturing apparatus equipped with a cooling roll, and FIG.
4B shows a manufacturing apparatus equipped with a cooling plate, and FIG.
Shows a schematic configuration of a manufacturing apparatus equipped with a cold air device. Figure 4
Water or alcohol is used as the cooling refrigerant in (a) and FIG. 4 (b), and the cooling temperature can be changed arbitrarily. Further, the cooling device of FIG. 4 (c) is a non-contact type, so the cooling effect is weak, and therefore the air volume control can be arbitrarily changed. In addition, a method of applying cool air from above and below is desirable in order to make the cooling efficiency more stable.

To make the reversible thermosensitive recording material of the present invention,
For example, it can be produced by forming the heat-sensitive layer as a film on the support or molding it into a sheet by the following method. 1) A method in which a resin base material and an organic low molecular weight substance are dissolved in a solvent, which is applied onto a support member, and the solvent is evaporated to form a film or sheet. 2) The resin base material is dissolved in a solvent that dissolves only the resin base material, and the organic low molecular weight substance is pulverized or dispersed therein by various methods, and this is applied onto a support member, and the solvent is evaporated to form a film. Or the method of making a sheet. The solvent for forming the heat-sensitive layer or the heat-sensitive recording material can be variously selected depending on the type of the resin base material and the organic low molecular weight substance, for example, tetrahydrofuran, methyl ethyl ketone,
Methyl isobutyl ketone, chloroform, carbon tetrachloride,
Examples thereof include ethanol, toluene and benzene. The organic low molecular weight substance is precipitated as fine particles and exists in a dispersed state in the heat-sensitive layer obtained not only when the dispersion liquid is used but also when the solution is used.

In the present invention, the resin used as the resin base material of the thermosensitive layer of the reversible thermosensitive recording material is preferably a resin which can form a film or sheet, has good transparency and is mechanically stable. Examples of such resins include polyvinyl chloride; vinyl chloride-vinyl acetate copolymer, vinyl chloride-vinyl acetate-vinyl alcohol copolymer, vinyl chloride-vinyl acetate-maleic acid copolymer, vinyl chloride-acrylate copolymer. Vinyl chloride-based copolymers such as polymers; polyvinylidene chloride, vinylidene chloride-vinyl chloride copolymers, vinylidene chloride-based copolymers such as vinylidene chloride-acrylonitrile copolymers; polyesters; polyamides; polyacrylates or polymethacrylates or acrylates -Methacrylate copolymer; silicone resin and the like can be mentioned. These may be used alone or in admixture of two or more.

On the other hand, as the organic low molecular weight substance, any substance that changes from polycrystal to single crystal due to heat in the recording layer (changes within the temperature range of T _{1 to} T ₃ shown in FIG. 1) may be used. Generally a melting point of 30 to 200 ° C., preferably 50 to 150
The thing of about ℃ is used. Such organic low molecular weight substances include alkanols; alkane diols; halogen alkanols or halogen alkane diols; alkylamines; alkanes; alkenes; alkynes; halogen alkanes; halogen alkenes; halogen alkynes; cycloalkanes; cycloalkenes; cycloalkynes; saturated or Unsaturated mono- or dicarboxylic acids or their esters,
Amides or ammonium salts; saturated or unsaturated halogen fatty acids or their esters, amides or ammonium salts; arylcarboxylic acids or their esters, amides or ammonium salts; halogenallylcarboxylic acids or their esters, amides or ammonium salts; thioalcohols Thiocarboxylic acids or their esters,
Amine or ammonium salts; carboxylic acid esters of thioalcohol and the like. These may be used alone or in admixture of two or more. The carbon number of these compounds is 1
0-60, preferably 10-38, especially 10-30 are preferred. The alcohol group moiety in the ester may be saturated or unsaturated, and may be halogen-substituted. In any case, the organic low molecular weight substance is at least one of oxygen, nitrogen, sulfur and halogen in the molecule,
For example, -OH, -COOH, -CONH, -COOR,
_{-NH, -NH 2, -S -,} - S-S -, - O-, is preferably a compound containing a halogen and the like.

More specifically, as these compounds, lauric acid, dodecanoic acid, myristic acid, pentadecanoic acid, palmitic acid, stearic acid, behenic acid, nonadecanoic acid, araginic acid, henicosanoic acid, tricosanoic acid, lignoceric acid, pentacosan. Higher fatty acids such as acids, cerotic acid, heptacosanoic acid, montanic acid, melissic acid, oleic acid; esters of higher fatty acids such as methyl stearate, tetradecyl stearate, octadecyl stearate, octadecyl laurate, tetradecyl palmitate, and dodecyl behenate. ;

[0021]

[Chemical 1]

And the like, such as ether or thioether.
Among them, in the present invention, higher fatty acids, particularly palmitic acid, pentadecanoic acid, nonadecanoic acid, arachidic acid, henicosanoic acid, tricosanoic acid, lignoceric acid, stearic acid, behenic acid and the like, are preferably higher fatty acids having 16 or more carbon atoms and having 16 to 16 carbon atoms. 24 higher fatty acids are more preferred.

It is also possible to use one of the above-mentioned organic low-molecular substances as the organic low-molecular substance and another type of organic low-molecular substance as the substance for controlling the crystal growth. For example, stearic acid is used as an organic low molecular weight substance, and stearyl alcohol is used as a substance for controlling crystal growth. The weight ratio of the organic low molecular weight substance to the substance that controls the crystal growth of the organic low molecular weight substance is preferably about 1: 0.1 to 1: 0.8. When the substance that controls the crystal growth of the organic low molecular weight substance is below this range, the temperature range or energy range where it becomes transparent cannot be widened, and above this range, the opacity decreases.

The weight ratio of the organic low molecular weight substance to the resin base material in the heat sensitive layer is preferably about 2: 1 to 1:16, more preferably 1: 1 to 1: 3. If the ratio of the resin base material is below this range, it will be difficult to form a film in which the organic low molecular weight material is retained in the resin base material. Becomes difficult.

The thickness of the heat sensitive layer is preferably 1 to 3 μm, and 2
˜20 μm is more preferred. If the heat-sensitive layer is too thick, heat distribution will occur in the layer and it will be difficult to achieve uniform transparency. On the other hand, if the heat-sensitive layer is too thin, the white turbidity is lowered and the contrast is lowered. Further, the white turbidity can be increased by increasing the amount of the organic low molecular weight substance in the heat sensitive layer.

In addition to the above components, additives such as a surfactant and a high boiling point solvent may be added to the heat-sensitive layer in order to facilitate the formation of a transparent image. Specific examples of these additives are as follows. Examples of high boiling point solvents: tributyl phosphate, tri-2-phosphate
Ethylhexyl, triphenyl phosphate, tricresyl phosphate, butyl oleate, dimethyl phthalate, diethyl phthalate, dibutyl phthalate, diheptyl phthalate, di-n-octyl phthalate, di-2-ethylhexyl phthalate, diisononyl phthalate , Dioctyldecyl phthalate, diisodecyl phthalate, butylbenzyl phthalate,
Dibutyl adipate, di-n-hexyl adipate, di-2-ethylhexyl adipate, di-2 azelaate
-Ethylhexyl, dibutyl sebacate, di-2-ethylhexyl sebacate, diethylene glycol dibenzoate, triethylene glycol di-2-ethyl butyrate, methyl acetylricinoleate, butyl acetylricinoleate, butylphthalylbutyl glycolate, acetylcitric acid Tributyl.

Examples of surfactants and other additives: polyhydric alcohol higher fatty acid ester; polyhydric alcohol higher alkyl ether; polyhydric alcohol higher fatty acid ester, higher alcohol, higher alkylphenol, higher fatty acid higher alkylamine, higher fatty acid amide , Lower olefin oxide adducts of fats and oils or polypropylene glycol; acetylene glycol; Na, Ca, Ba or Mg salts of higher alkylbenzene sulfonic acid; higher fatty acid, aromatic carboxylic acid, higher fatty acid sulfonic acid, aromatic sulfonic acid, sulfuric acid monoester Or Ca, Ba or Mg salt of phosphoric acid mono- or di-ester; low degree of sulfated oil; poly long chain alkyl acrylate; acrylic oligomer; poly long chain alkyl methacrylate; long chain alkyl methacrylate to amine-containing mono Chromatography copolymers; styrene-maleic anhydride copolymer; olefin-maleic anhydride copolymer.

On the heat-sensitive layer of the present invention, in order to prevent the surface of the transparent part from being deformed by heat and pressure of a heating means such as a thermal head by a writing method to reduce the transparency of the transparent portion, conventional reversible heat-sensitive recording is carried out. A protective layer may be provided similarly to the material. The thickness of the protective layer is 1 to 15 μm, preferably about 2 to 10 μm. If the thickness of the protective layer is less than 1 μm, the heat-sensitive layer cannot be used as a protective layer,
If it exceeds m, the thermal sensitivity of the heat-sensitive layer is lowered. Examples of the material of the protective layer laminated on the heat-sensitive layer include silicone rubber, silicone resin, polysiloxane graft polymer, ultraviolet curable resin, electron beam curable resin and the like. In any case, a solvent is used at the time of coating, but it is desirable that the solvent is difficult to dissolve the resin of the heat sensitive layer and the organic low molecular weight substance. Examples of the solvent that hardly dissolves the resin and the organic low molecular weight substance in the heat-sensitive layer include n-hexane, methyl alcohol, ethyl alcohol, isopropyl alcohol and the like, and the alcohol solvent is particularly preferable from the viewpoint of cost.

Further, an intermediate layer can be provided between the protective layer and the reversible recording material in order to protect the reversible recording material from the solvent of the protective layer forming liquid, the monomer component and the like (JP-A-1-133781). No. publication). As the material for the intermediate layer, the following thermosetting resins and thermoreversible resins can be used in addition to those listed as the resin base material in the thermosensitive layer.
That is, specifically, polyethylene, polypropylene, polystyrene, polyvinyl alcohol, polyvinyl butyral, polyurethane, saturated polyester, unsaturated polyester, epoxy resin, phenol resin, polycarbonate, polyamide and the like can be mentioned. Although the thickness of the intermediate layer varies depending on the use, it is preferably about 0.1 to 2 μm. If it is less than this, the protective effect is lowered, and if it is more than this, the thermal sensitivity is lowered.

[0030]

EXAMPLES All parts and percentages herein are by weight.

Example 1 On a PET film having a thickness of 50 μm, stearic acid 6 parts eicosane diacid 4 parts diisodecyl phthalate 2 parts vinyl chloride-vinyl acetate-phosphorus ester copolymer 20 parts (Denka Vizier # manufactured by Denki Kagaku Kogyo KK) 1000P) THF 150 parts Toluene 15 parts A solution is applied by a wire bar head and dried 1
An adhesion amount of 20 g / m ² was obtained. Next, the reversible thermosensitive recording material of the present invention is obtained by heating and drying at 120 ° C., turbidity, heating and drying at 90 ° C., and then cooling by a cooling roll (temperature 30 ° C., contact time 5 seconds). Created.

Example 2 A reversible thermosensitive recording material of the present invention was prepared in the same manner as in Example 1 except that the temperature of the cooling roll in Example 1 was changed to 45 ° C.

Example 3 A reversible thermosensitive recording material of the present invention was prepared in the same manner as in Example 1 except that the temperature of the cooling roll in Example 1 was changed to 40 ° C. and the contact time was changed to 2 seconds.

Example 4 Instead of the cooling roll of Example 1, a cooling plate (temperature: 30 ° C.,
The reversible thermosensitive recording material of the present invention was prepared by cooling at a contact time of 5 seconds).

Example 5 A reversible thermosensitive recording material of the present invention was prepared by cooling with cold air (temperature: 30 ° C., air volume: 10 m / s, time: 5 seconds) instead of the cooling roll of Example 1.

Comparative Example 1 The cooling roll conditions of Example 1 were set to a temperature of 15 ° C. and a contact time of 5
A comparative reversible thermosensitive recording material was prepared in the same manner as in Example 1 except that the time was changed to 2 seconds.

Comparative Example 2 The cooling roll conditions of Example 1 were set to a temperature of 15 ° C. and a contact time of 3
A comparative reversible thermosensitive recording material was prepared in the same manner as in Example 1 except that the time was changed to 0 second.

Comparative Example 3 The cooling roll conditions of Example 1 were set to a temperature of 50 ° C. and a contact time of 2
A comparative reversible thermosensitive recording material was prepared in the same manner as in Example 1 except that the time was changed to 2 seconds.

The transparent density of the reversible thermosensitive recording material prepared as described above was measured by a Macbeth reflection densitometer (RD-514).
The results measured in Table 1 are shown in [Table 1] below.

[0040]

[Table 1]

Example 6 On the reversible thermosensitive recording material of Example 1, a solution of polyamide resin (CM-8000 manufactured by Toray Industries, Inc.) 5 parts methyl alcohol 90 parts was applied with a wire bar and dried by heating to about 0. A 3 μm-thick intermediate layer is provided, and a butyl acetate solution of urethane acrylate-based UV-curable resin (Unidick C7-157, manufactured by Dainippon Ink and Chemicals, Inc.) is applied on the intermediate layer with a wire bar, followed by heating and drying, and then 80 W / cm. The reversible thermosensitive recording material of the present invention was prepared by irradiating ultraviolet rays with the ultraviolet lamp for 3 seconds to form an overcoat layer having a thickness of about 3 μm. Using this reversible heat-sensitive recording material, an image recording apparatus equipped with a thermal head (8 dot / mm), an erasing head, and a cooling device was used to cool a cooling roll (temperature 30 ° C., contact time 2 seconds). It became transparent under the conditions.

Example 7 An image recording apparatus in which the cooling roll conditions of Example 6 were changed to a temperature of 45 ° C. and a contact time of 2 seconds was made transparent in the same manner as in Example 6.

Example 8 In the same manner as in Example 6, the image was made transparent by changing the cooling roll conditions of Example 6 to a temperature of 40 ° C. and a contact time of 2 seconds.

Example 9 The cooling roll conditions of Example 6 were temperature 30 ° C. and contact time 10
The image was made transparent in the same manner as in Example 6 by using the image recording apparatus changed to the second.

Example 10 An image recording apparatus in which the cooling roll of Example 6 was changed to a cooling plate (temperature: 30 ° C., contact time: 2 seconds) was made transparent in the same manner as in Example 6.

Example 11 The cooling roll of Example 6 was cooled with cold air (temperature 30 ° C., air volume 5 m /
s for 2 seconds), and the image recording apparatus was changed to transparent in the same manner as in Example 6.

Comparative Example 4 A transparent film was obtained in the same manner as in Example 6 except that the cooling roll conditions in Example 6 were changed to a temperature of 15 ° C. and a contact time of 2 seconds.

Comparative Example 5 The cooling roll conditions of Example 6 were set to a temperature of 15 ° C. and a contact time of 30.
It was made transparent in the same manner as in Example 6 except that it was changed to seconds.

Comparative Example 6 A transparent film was obtained in the same manner as in Example 6 except that the cooling roll conditions in Example 6 were changed to a temperature of 50 ° C. and a contact time of 2 seconds.

The transparent density of the reversible thermosensitive recording material which has been made transparent as described above is measured by a Macbeth reflection densitometer (RD-5).
The results measured in 14) are shown in [Table 2] below.

[0051]

[Table 2]

[0052]

EFFECTS OF THE INVENTION By heating the reversible thermosensitive recording material which becomes cloudy as described above to the clearing temperature and then setting the cooling device and conditions, it becomes possible to make the clearing process in a short time in the manufacturing process. The reprocessing is eliminated, and the effect of reducing the manufacturing cost can be obtained. Furthermore, even when erasing image records,
By setting the cooling device and conditions, it is possible to make the material transparent in a short time, and it is possible to obtain a high-contrast image by improving the density of the transparent material, and there is an effect that there is no defective erasing.

[Brief description of drawings]

FIG. 1 is a characteristic explanatory view of a thermoreversible thermosensitive recording material.

FIG. 2 is a graph showing a relationship between a cooling method after heating to a clearing temperature and a clearing concentration.

3A and 3B are schematic explanatory views showing an image recording apparatus according to the present invention, in which FIG. 3A shows a cooling roll system, FIG. 3B shows a cooling plate system, and FIG. 3C shows a cold air system.

FIG. 4 is a schematic explanatory view showing a manufacturing apparatus for realizing the present invention, in which (a) shows a cooling roll system, (b) shows a cooling plate system, and (c) shows a cold air system.

[Explanation of symbols]

 1 Thermal Head 2 Reversible Thermosensitive Recording Material 3 Platen Roll 4 Cooling Device 5 Erasing Device 6 Coating Head 7 First Drying Box 8 Second Drying Box

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Nogiri Dori 1-3-6 Nakamagome, Ota-ku, Tokyo Inside Ricoh Co., Ltd.

Claims (3)

[Claims] 1. A reversible device comprising a support and a heat-sensitive layer comprising a resin base material and an organic low-molecular substance dispersed in the resin base material as a main component and having a transparency reversibly changing depending on temperature. A method for making a reversible thermosensitive recording material transparent, which comprises heating the reversible thermosensitive recording material to a clearing temperature and then cooling the reversible thermosensitive recording material to a temperature of 30 ° C. or higher and 45 ° C. or lower. 2. The reversible thermosensitive recording material according to claim 1, wherein the reversible thermosensitive recording material is heated to a clearing temperature and then cooled to a temperature of 30 ° C. or higher and 45 ° C. or lower in 10 seconds or less. Transparent method. 3. A reversible device comprising a support and a heat-sensitive layer comprising a resin base material and an organic low-molecular substance dispersed in the resin base material as a main component and having a transparency reversibly changing depending on temperature. Reversible thermosensitive recording comprising: heating means for heating the thermosensitive recording material; and cooling means for cooling the reversible thermosensitive recording material to a temperature of 30 ° C. or higher and 40 ° C. or lower after the heating. Material image recording device.