JPH0872415A - Image recording method and apparatus of reversible thermal recording medium - Google Patents

Abstract

PURPOSE: To record an image of a second color on a background of a first color by heating a recording medium to a second temp. region or higher and cooling a part thereof to a third temp. region and heating the cooled part to a first temp. region before cooling the recording medium to a third specific temp. region. CONSTITUTION: A reversible thermal recording medium is obtained by providing a thermal recording layer 2 composed of a reversible thermal recording material becoming a first color state when heated to a first specific temp. region higher than the normal temp. and subsequently cooled and becoming a second color state when heated to a relatively higher second specific temp. region and subsequently cooled to a third specific temp. region lower than the first specific temp. region on a support 3. In this case, the whole of the recording medium 8 is heated to the second specific temp. region or higher by a heating roller 6 and a part thereof is cooled to a third specific temp. region by a cooling device 5 and the cooled part is heated to the first specific temp. region and the whole of the recording medium 8 is cooled to the third specific temp. region to record an image of a second color on a background of a first color.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and apparatus for recording an image on a reversible thermosensitive recording medium capable of repeating writing and erasing of information by heating and cooling, and more specifically, a reversible thermosensitive recording material is used. The present invention also relates to an image recording method such as a heat-sensitive film and a card which can be repeatedly used, and an apparatus useful for the recording.

[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 effective material, one having a heat-sensitive layer obtained by dispersing an organic low molecular weight substance such as a higher alcohol or a higher fatty acid in a resin such as polyester on a support is disclosed in, for example, JP-A-54-54.
No. 119377, No. 55-154198, and the like. 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 can be formed and can be erased. As a method of recording an image of the first color against the background of the second color, an image recording method such as a method of controlling the applied energy of the thermal head (Japanese Patent Laid-Open No. 5-50768) is also known. ing.

[0003]

However, in a reversible thermosensitive recording medium having a thermosensitive recording layer in which an organic low molecular weight substance such as a higher alcohol or a higher fatty acid is dispersed in a resin such as polyester on the above-mentioned support. However, the printing becomes cloudy, which is not preferable for OA applications, and in general, a transparent image on a cloudy background is required. Further, as a method for recording a transparent image against a background of cloudy background, there is a method disclosed in Japanese Patent Laid-Open No.
There is a method of controlling the applied energy of the thermal head, which is known from Japanese Patent No. 50768, but there is a drawback that the energy control is difficult and the apparatus becomes complicated. An object of the present invention is to obtain a first color state by heating and cooling to a first specific temperature range higher than room temperature, and after heating to a second specific temperature range higher than the first specific temperature range. The second color is applied to a reversible thermosensitive recording medium provided with a thermosensitive recording layer made of a reversible thermosensitive recording material which becomes a second color state by cooling to a third specific temperature range lower than the specific temperature range of Provided is a method for easily recording a clear image of a first color on a background, and an apparatus suitable for performing the method.

[0004]

According to one aspect of the present invention, a state of a first color is achieved by heating and cooling to a first specific temperature range higher than room temperature, and the temperature is higher than that of the first specific temperature range. A support is provided with a heat-sensitive recording layer made of a reversible heat-sensitive recording material which is in a second color state by heating to a second high specific temperature range and then cooling to a third specific temperature range lower than the first specific temperature range. In the method of recording an image on the reversible thermosensitive recording medium provided above, after heating the entire recording medium to a second specific temperature range or higher, a part of the recording medium is cooled to a third specific temperature range. Then, after the portion cooled to the third specific temperature range is heated to the first specific temperature range, the entire recording medium is cooled to the third specific temperature range so that the first color is used as a background. An image of the second color is recorded.

According to another aspect of the present invention, a second color higher than the first specific temperature range is obtained by heating to a first specific temperature range higher than room temperature and then cooling to obtain a first color state. A heat-sensitive recording layer made of a reversible heat-sensitive recording material, which was in a second color state by being heated to a specific temperature range and then cooled to a third specific temperature range lower than the first specific temperature range, was provided on a support. In an apparatus for recording an image on a reversible thermosensitive recording medium, at least one heating means for heating the entire recording medium to a second specific temperature range, and cooling a part of the thermal recording layer to a third specific temperature range. At least one cooling means and at least one heating means for heating the portion cooled to the third specific temperature range to the first specific temperature range, and the second method against the background of the first color by the above method. It is possible to record images of different colors. The features.

Hereinafter, the present invention will be described in more detail. According to the present invention, the first color state is achieved by heating and cooling to a first specific temperature range higher than room temperature, and after heating to a second specific temperature range higher than the first specific temperature range. Using a reversible thermosensitive recording medium having a thermosensitive recording layer made of a reversible thermosensitive recording material, which is in a second color state when cooled to a third specified temperature range lower than the specified temperature, on a support, After heating the recording medium to the second specific temperature range, a part of the recording medium is cooled to the third specific temperature range, and then the cooled part is heated to the first specific temperature range. An image recording method and apparatus for recording an image of a second color against a background of the first color by cooling to a specific temperature range. By carrying out this method, the recording medium shows the temperature history of the image portion (shown by a broken line), the non-image portion A (shown by a solid line), and the non-image portion B (shown by a dashed line) as shown in FIG. Follow.

The image portion A is heated to the second specific temperature range, then once cooled to the third specific temperature range, and then to the first specific temperature range.
The temperature history of forming the first color by being cooled to the third specific temperature range after being heated to the third specific temperature range, and the non-image part is heated to the second specific temperature range,
Basically, the temperature history of A that is cooled to the third specific temperature range is taken. Also, because the non-image area does not become the first color completely unless it is cooled to a temperature lower than the third specific temperature when heated to the second specific temperature range due to the characteristics of the recording medium, the non-image area is similar to the non-image area B. In addition, the temperature history may be such that the non-image part does not fall to the lower limit of the first specific temperature range. After heating the entire recording medium to the second specific temperature range, the recording medium is cooled to the third specific temperature range, and then the cooled portion is placed between the first specific temperature range and the second specific temperature range. After heating to the temperature of, the entire recording medium is cooled. It is also possible to obtain an image of an intermediate color between the first color and the second color by such a method.

Changes in the color state of the reversible thermosensitive recording material include changes in transmittance, reflectance, absorption wavelength, scattering degree, etc., and an actual reversible thermosensitive recording material is displayed by a combination of these changes. Are doing. More specifically, at present, it can be classified into two types of systems: (a) a material in which the transparent state and the cloudy state reversibly change, and (b) a material in which the color such as a dye changes reversibly. As (a), as described in the prior art, a typical example is one in which a heat-sensitive recording layer in which an organic low molecular weight substance such as higher alcohol or higher fatty acid is dispersed in a resin base material such as polyester is provided.
Further, as (b), a leuco-based heat-sensitive recording material in which reversibility is enhanced (eg, JP-A-2-188293, JP-A-2-1883).
-188294) and the like.

The "transparent state" and the "white turbid opaque state" in "a material composed of a resin base material and an organic low-molecular substance dispersed in the resin base material, which reversibly changes the transparent and opaque state by heating" The difference is estimated as follows. That is, in the case of (I) transparent, the particles of the organic low molecular weight substance dispersed in the resin base material are in close contact with each other without any gap between the organic low molecular weight substance and the resin base material, and there is no void inside the particles. Light entering from one side does not scatter and is transmitted to the other side, so it looks transparent. Also, in the case of (II) white turbidity, the particles of the organic low molecular weight substance are composed of fine crystals of the organic low molecular weight substance. That is, there is a gap at the crystal interface or at the interface between the particles and the resin base material, and light incident from one side is refracted at the interface between the air gap and the crystal, and the air gap and the resin, and appears white because it is scattered.
And so on.

In FIG. 2 (representing the change in transparency due to heat), a thermosensitive recording layer mainly composed of a resin base material and a dispersed organic low molecular weight substance in the resin base material is, for example, a third recording layer. In a specific temperature range (temperature T ₀ or lower), the white turbid state is opaque. When it is heated, it gradually becomes transparent from the temperature T _1, and when it is heated to the first specific temperature range (T _{2 to} T ₃ ), it becomes transparent. In this state, it is returned to the third specific temperature range again. Remains transparent. This is because the resin begins to soften near the temperature T ₁ , and as the softening progresses, the resin shrinks and reduces the interface between the resin and the organic low-molecular substance particles or the voids in the particles, so that the transparency gradually increases, and the first The organic low-molecular weight substance becomes a semi-molten state in the specific temperature range of, and it becomes transparent by filling the remaining voids with the molten organic low-molecular weight substance, and the seed crystal is cooled while the seed crystal remains. It is considered that because the resin is still in a softened state, the resin follows the volume change of the particles accompanying the crystal, and voids are not formed, so that the transparent state is maintained. Further heating to the second specific temperature range (T ₄ or higher) results in a semitransparent state 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. This is because after the organic low molecular weight substance has completely melted in the second specific temperature range, it becomes a supercooled state and crystallizes at a temperature slightly higher than the third specific temperature range, at which time the resin changes in volume due to crystallization. This is probably because voids cannot be followed and voids occur. However, the temperature-transparency change curve shown in FIG. 2 is only a representative example, and the transparency of each state may change depending on the material by changing the material.

Therefore, the heat-sensitive recording 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. By arranging a colored sheet on the back surface of such a heat-sensitive recording layer, an image of the color of the colored sheet or a white image of the color of the colored sheet can be formed on a white background. Further, when projected by an OHP (overhead projector) or the like, the cloudy part becomes a dark part, and the transparent part transmits light and becomes a bright part on the screen.

In order to prepare the reversible thermosensitive recording medium according to the present invention, generally, (1) a solution in which two components of a resin base material and an organic low molecular weight substance are dissolved, or (2) a solution of a resin base material (the solvent is organic) A low-molecular substance that does not dissolve at least one of them is used as a fine particle dispersion of an organic low-molecular substance on a support such as a plastic film, glass plate, metal plate, etc. A layer may be formed.

The solvent for forming the heat-sensitive recording layer can be variously selected depending on the types of the resin base material and the organic low molecular weight substance.
Examples thereof include tetrahydrofuran, methyl ethyl ketone, methyl isobutyl ketone, chloroform, carbon tetrachloride, ethanol, toluene, benzene and the like. The organic low molecular weight substance is precipitated as fine particles and exists in a dispersed state in the thermosensitive recording layer obtained not only when the dispersion is used but also when the solution is used.

The resin base material used in the heat-sensitive recording layer is a material which forms a layer in which an organic low molecular weight substance is uniformly dispersed and held, and which affects the transparency at maximum transparency. Therefore, the resin base material is preferably a resin having good transparency, mechanical stability, and good film forming property.

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- Vinyl chloride-based copolymers such as acrylate copolymers; polyvinylidene chloride, vinylidene chloride-vinyl chloride copolymers, vinylidene chloride-based copolymers such as vinylidene chloride-acrylonitrile copolymers; polyesters; polyamides; polyacrylates or polyacrylates Methacrylate or acrylate-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, the organic low molecular weight substance may be any substance that changes from polycrystal to single crystal due to heat in the thermosensitive recording layer, and generally has a melting point of 30 to 200 ° C., preferably 50 to 15
The thing of about 0 degreeC is used. Such organic low-molecular 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; allylcarboxylic acids or their esters,
Amides or ammonium salts; halogenallylcarboxylic acids or their esters, amides or ammonium salts;
Thioalcohol; thiocarboxylic acid or its ester, amine or ammonium salt; carboxylic acid ester of thioalcohol and the like. These are single or 2
Used as a mixture of two or more species. The carbon number of these compounds is preferably 10 to 60, preferably 10 to 38, and particularly preferably 10 to 30. The alcohol group portion 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-, -C.
_{OOR, -NH -, - NH 2} , -S -, - S-S -, -
A compound containing O-, halogen or the like is preferable.

More specifically, these compounds include higher fatty acids such as lauric acid, dodecanoic acid, myristic acid, pentadecanoic acid, palmitic acid, stearic acid, behenic acid, nonadecanoic acid, alginic acid and oleic acid; methyl stearate. , Esters of higher fatty acids such as tetradecyl stearate, octadecyl stearate, octadecyl laurate, tetradecyl palmitate and dodecyl behenate; Etc., such as ester or thioether. Among them, in the present invention, higher fatty acids, particularly higher fatty acids having 16 or more carbon atoms such as palmitic acid, stearic acid, behenic acid and lignoceric acid are preferable, and higher fatty acids having 16 to 24 carbon atoms are more preferable.

In order to widen the temperature range in which the material can be made transparent, the organic low molecular weight substances described in this specification may be appropriately combined, or such organic low molecular weight substances may be combined with other materials having different melting points. . These are disclosed, for example, in JP-A-63
JP-A-39378, JP-A-63-130380, and Japanese Patent Application Nos. 63-14754 and 1-14011.
However, the present invention is not limited thereto. The weight ratio of the organic low molecular weight substance to the resin base material in the thermosensitive recording layer is 2: 1 to 1:16.
The degree is preferable, and 1: 2 to 1: 6 is more preferable. When the ratio of the resin base material is less than this, it becomes difficult to form a film in which the organic low molecular weight substance is held in the resin base material, and when the ratio is more than this, the amount of the organic low molecular weight substance is small,
Opacification becomes difficult.

In addition to the above components, additives such as a surfactant and a high boiling point solvent may be added to the heat-sensitive recording 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 Lower olefin oxide adducts of amides, oils and fats or polypropylene glycols; acetylene glycols; Na, Ca, Ba or Mg salts of higher alkylbenzene sulfonic acids; higher fatty acids, aromatic carboxylic acids, higher fatty acid sulfonic acids, aromatic sulfonic acids, sulfuric acid monosulfates. Ca, Ba or Mg salt of ester or 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.

When the image of the recording medium of the present invention is used as a reflection image, if a layer that reflects light is provided on the back surface of the thermosensitive recording layer, the contrast can be increased even if the thickness of the thermosensitive recording layer is reduced. . Specifically, Al, N
The vapor deposition of i, Sn, etc. may be mentioned (Japanese Patent Laid-Open No. 64-64-
No. 14079).

A protective layer may be provided on the heat-sensitive recording layer to protect the heat-sensitive layer. As a material for the protective layer (thickness of 0.1 to 5 μm) to be laminated on the heat-sensitive recording layer, silicone rubber, silicone resin (Japanese Patent Laid-Open No. 63-
221087), polysiloxane graft polymer (described in Japanese Patent Application No. 62-152550), ultraviolet curable resin or electron beam curable resin (Japanese Patent Application No. 63-31).
No. 0600) 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 recording 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.

Furthermore, an intermediate layer may be provided between the protective layer and the heat-sensitive recording layer in order to protect the heat-sensitive recording layer from the solvent, monomer components and the like of the liquid for forming the protective layer (Japanese Patent Laid-Open No. HEI-1.
-133781). As the material for the intermediate layer, the following thermosetting resins and thermoplastic resins can be used in addition to those listed as the resin base material in the thermosensitive recording layer.
That is, polyethylene, polypropylene, polystyrene,
Examples thereof include polyvinyl alcohol, polyvinyl butyral, polyurethane, saturated polyester, unsaturated polyester, epoxy resin, phenol resin, polycarbonate and polyamide.

By the way, when the reversible thermosensitive recording medium is heated to the second specific temperature range, the heating temperature is heat resistance of the recording medium, repeated durability, easiness of cooling a part of the recording medium, etc. Therefore, it is preferably within 10 ° C. from the lower limit (T ₄ ) of the second specific temperature range. Further, in order to make temperature control easier and obtain a clearer image, the first specific temperature range (T _{2 to} T ₃ ) of the recording medium is broader (Japanese Patent Laid-Open No. 6-58242).
The gazettes such as 3-39378) are preferably used, and those having a temperature range of 10 ° C. or higher are particularly preferable.

The heating means may be any means as long as it uniformly heats the recording medium.
Among these, the following means are suitable. Means by solid contact ・ ・ ・ Means for contacting hot plate, heat roller, heat belt, etc.Means by liquid contact ・ ・ ・ Means for contacting recording medium with heated liquid Gas means ・ ・ ・ Recording heated steam Means for jetting the medium, means for passing the medium through the dryer box, etc. Means for using an alternating magnetic field: an alternating magnetic field generated by an alternating magnetic field generator typified by an electromagnetic cooker using a conductive material for the support. Means for applying a magnetic field and heating the support, etc. Means using electromagnetic waves: heating means using visible light, infrared rays, microwaves, etc. In the means using visible light, infrared rays, the support, the thermosensitive recording layer It is necessary to contain the absorbing material in the.

As the cooling means, any means may be used as long as it can cool the heat-sensitive recording layer to room temperature in a short time, but the following means are suitable among them. Means by solid contact: Means for contacting solids in a third specific temperature range or lower (T ₀ or lower), etc. Means by liquid: Means for spraying water, highly volatile solvent, etc. Means by gas: Means for injecting compressed air, CFC gas, or other gas with a nozzle

Specific examples of the image recording apparatus having these heating / cooling means are shown in FIGS. The numbers in the figure are 5: cooling device, 6: heat roller (second
In a specific temperature range), 7: transport roller, 8: reversible thermosensitive recording medium, 9: temperature holding belt, 10: heat roller (first specific temperature range or lower), 11: It represents a support plate.

In FIG. 6, after the recording medium 8 is heated to the second specified temperature range by the heat roller 6, a part of the recording medium 8 which is in contact with the heat roller 6 is cooled by the cooling device 5 to the third specified temperature range. After cooling a part of the recording medium 8 cooled by the heat of the heat roller 6 to the first specific temperature range again, the entire recording medium 8 is naturally cooled to the third specific temperature range. The recording medium is an apparatus for recording an image by tracing the temperature history of the image portion and the non-image portion A as shown in FIG.

FIG. 7A shows that the temperature holding belt 9 is in the second specified temperature range while the temperature holding belt 9 is in contact with the heat roller 6, and the first specified temperature is maintained while the temperature holding belt 9 is separated from the recording medium 8 after the cooling device 5. When the temperature of the recording medium 8 reaches the temperature range, the recording medium 8 records the image by tracing the temperature history of the image portion and the non-image portion A as shown in FIG. 1 by the temperature holding belt 9 and the cooling device 5.

In FIG. 8, the recording medium 8 is heated to the second specified temperature range by the heat roller 6, and while the recording medium 8 is separated from the heat roller 6 and comes into contact with another heat roller 10, the third specified temperature range is shown. Under the condition that the higher temperature is maintained, a part of the recording medium 8 is cooled to the third specific temperature range by the cooling device 5 during that time, and the whole of the recording medium 8 is again heated to the first specific temperature range by the heat roller 10. The recording medium 8 is a device for recording an image by tracing the temperature history of the image portion and the non-image portion B as shown in FIG. 1 by being heated and then naturally cooled to the third specific temperature range.

In FIG. 9, after the recording medium 8 is heated to the second specific temperature range by the heat roller 6, a part of the thermal recording layer is cooled to the third specific temperature range by the cooling device 5, and the thermal recording is performed. By heating a part of the layer to the first specific temperature range by the heat of the support, the recording medium 8 is changed to the one shown in FIG.
In the apparatus for recording an image, the non-image area A as shown in FIG. 1 and a part of the heat-sensitive recording layer trace the temperature history of the non-image area shown in FIG.

[0032]

EXAMPLES The present invention will be specifically described with reference to the following examples. Parts herein are by weight. The first and second
And the description of the third specific temperature range is shown in FIGS.
The horizontal axis indicates the reflection density when the temperature is plotted on the horizontal axis and then cooled to room temperature.

Example 1 Behenic acid (B-95 manufactured by Miyoshi Yushi Co., Ltd.) on a transparent polyester film (HLS50 manufactured by Teijin Co., Ltd.) having a thickness of about 50 μm 1 part Lignoceric acid (FL-88 manufactured by Miyoshi Yushi Co., Ltd.) 3 Part Eicoic acid 2 acid (SL-20-90 manufactured by Okamura Oil Co., Ltd.) 5 parts Vinyl chloride-vinyl acetate copolymer 30 parts (Kaneka Chemical Co., Ltd .: Kaneka M2018) THF 150 parts Toluene 50 parts Wire solution It is coated with a bar and dried by heating at 120 ° C for 3 minutes, becoming a cloudy state at a second specific temperature of about 120 ° C or higher, and a first specific temperature range of 90 ° C or higher 12
It becomes transparent at 0 ℃ or below, and the third specific temperature range is 40 ℃.
The following reversible thermosensitive recording layer (thickness of about 10 μm) is provided, and 75% of urethane acrylate UV curable resin 10 parts butyl acetate solution (Dainippon Ink and Chemicals Co., Ltd .: Unidic C7-157) isopropyl alcohol Apply a solution consisting of 10 parts with a wire bar, and heat and dry it to 80
A reversible thermosensitive recording medium (Fig. 4) was prepared by irradiating ultraviolet rays with a w / cm ultraviolet lamp to cure it, providing a protective layer of about 3 µm thickness, and heating it to 80 ° C to make the thermosensitive recording layer transparent. did. While the reversible thermosensitive recording medium was heated by a hot plate at 125 ° C., a part of the recording medium was brought into contact with a part of the recording medium at a temperature of 25 ° C. for the letter A of the alphabet A to cool the part of the recording medium. Release the type plate from about 0.7
After a second, the entire recording medium was separated from the hot plate and naturally cooled. In this way, the image shown in FIG. 3 was formed on the recording medium.

Example 2 The reversible thermosensitive recording medium of Example 1 was used to prepare a thermoreversible thermosensitive recording medium (FIG. 5) in which a silicone rubber sheet having a thickness of about 3 mm was attached to the support to increase the heat capacity of the support. , 125
In a state of heating up to 125 ° C on a hot plate of ℃, a part of the letter A of the alphabet made of rubber at 25 ° C is brought into contact with one part for about 1 second to cool, and the type plate, the recording medium and the hot plate are separated at the same time and naturally Cooled. Then, the temporarily cooled portion became transparent by the heat of the support, and the image shown in FIG. 3 was formed.

Example 3 The thermoreversible thermosensitive recording medium of Example 2 was heated to 125 ° C. on a 125 ° C. hot plate, and then the recording medium was separated from the hot plate and naturally cooled while the recording medium was released.
The temperature was kept above the specified temperature range, a part of it was cooled by applying compressed air from the nozzle, and then the whole was naturally cooled. As a result, the cooled part became transparent by the heat of the support, and a transparent image was formed.

Example 4 As a cooling means in Example 3, a means for injecting ethanol from a coating nozzle was used. Then, the same result as in Example 3 was obtained. At this time, the liquid serving as the cooling means may be any liquid as long as it can cool the recording medium to the third specific temperature, but a liquid having a high volatility is preferable because it causes dripping.

Example 5 An apparatus having the form shown in FIG. 6 was prepared by using a platen roller of a wire dot printer as a heat roller (125 ° C.). As the cooling means, a cloth tape moistened with ethanol was used instead of the ink ribbon, and the cloth tape was brought into contact with the reversible thermosensitive recording medium of Example 1 by wire dots so that a part of the recording medium was exposed to the third specific temperature range. Cool down. With this apparatus, a transparent image could be formed on the recording medium.

Example 6 The reversible thermosensitive recording medium of Example 1 was formed into a belt, and a device shown in FIG. 7 (a) having a rubber type plate as a cooling means was prepared. The temperature of the heat roller 6 was 125 ° C., and a belt made of silicone rubber was used as the temperature holding belt 9. The portion of the temperature holding belt 9 that is in contact with the heat roller 6 is set to the second specific temperature range, and the temperature holding belt 9 is separated from the heat roller 6 and reaches the transport roller 7 in the first specific temperature range. The line speed is adjusted to. A support plate 11 was attached to the back side (support side) of the contact surface between the type plate (cooling device 5) and the thermosensitive recording layer as shown in FIG. 7 (b). With this apparatus, a transparent image could be formed on the recording medium 8.

[0039]

As is apparent from the description of the embodiments, according to the image recording method and apparatus of the present invention, after heating in the first specific temperature range higher than room temperature, the third specific temperature lower than the first specific temperature range. A reversible thermosensitive recording material which becomes a first color state by cooling to a range, and becomes a second color state by cooling after heating in a first specific temperature range higher than the first specific temperature range. , It became easier to record the image of the second color against the background of the first color, and the apparatus was simplified.

[Brief description of drawings]

FIG. 1 is a graph showing the temperature history of a reversible thermosensitive recording medium.

FIG. 2 shows changes in transparency of a reversible thermosensitive recording medium according to the present invention due to heat.

FIG. 3 is an example of an image obtained by the present invention.

FIG. 4 is a sectional view of an example of a reversible thermosensitive recording medium.

FIG. 5 is a sectional view of an example of a reversible thermosensitive recording medium.

FIG. 6 is a schematic configuration diagram of an example of an image recording apparatus using the means of the present invention.

FIG. 7 is a schematic configuration diagram of an example of an image recording apparatus using the means of the present invention.

FIG. 8 is a schematic configuration diagram of an example of an image recording apparatus using the means of the present invention.

FIG. 9 is a schematic configuration diagram of an example of an image recording apparatus using the means of the present invention.

FIG. 10 shows respective first, second and third specific temperature ranges of the reversible thermosensitive recording medium.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Protective layer 2 Thermal recording layer 3 Support 4 Silicone rubber 5 Cooling device 6,10 Heat roller 7 Conveying roller 8 Reversible thermal recording medium 9 Temperature holding belt 11 Support plate

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Akira Suzuki 1-3-6 Nakamagome, Ota-ku, Tokyo Within Ricoh Co., Ltd. (72) Yoshihiko Hotta 1-3-6 Nakamagome, Ota-ku, Tokyo Shares Within Ricoh Company (72) Inventor Kuniparent Moroboshi 1-3-6 Nakamagome, Ota-ku, Tokyo Within Ricoh Company, Ltd.

Claims (6)

[Claims] 1. A state of the first color is obtained by heating and cooling to a first specific temperature range higher than room temperature, and after heating to a second specific temperature range higher than the first specific temperature range. An image is formed on a reversible thermosensitive recording medium in which a thermosensitive recording layer made of a reversible thermosensitive recording material, which is in a second color state when cooled to a third specific temperature range lower than the first specific temperature range, is provided on a support. In the method of recording, the whole recording medium is heated to a second specific temperature range or higher, and then a part of the recording medium is cooled to a third specific temperature range, and then to a third specific temperature range. After heating the cooled portion to the first specific temperature range, the entire recording medium is cooled to the third specific temperature range to record an image of the second color against the background of the first color. Characteristic image recording method. 2. The whole of the recording medium is heated to a second specific temperature range, then a part of the heat-sensitive recording layer is cooled to a third specific temperature range, and the temperature of the support is set to the first specific temperature range. By maintaining the above, the cooled portion of the thermosensitive recording layer is heated to the first specific temperature range by the heat of the support, and then the entire recording medium is cooled to the third specific temperature range. The image recording method according to claim 1, wherein an image of the second color is recorded against the background of the first color. 3. A state of the first color is obtained by heating and cooling to a first specific temperature range higher than room temperature, and after heating to a second specific temperature range higher than the first specific temperature range. An image is formed on a reversible thermosensitive recording medium in which a thermosensitive recording layer made of a reversible thermosensitive recording material, which is in a second color state when cooled to a third specific temperature range lower than the first specific temperature range, is provided on a support. A recording device for recording at least one heating means for heating the entire recording medium to a second specific temperature range, and at least one cooling means for cooling a part of the heat-sensitive recording layer to a third specific temperature range; At least one heating means for heating the part cooled to the third specific temperature range to the first specific temperature range, and the second color against the background of the first color according to the method of claim 1 or 2. Reversibility characterized by recording images of Image recording device for thermal recording medium. 4. The heating means is at least one of a means for bringing a heated solid, liquid or gas into contact with the recording medium, or a non-contact means using alternating magnetic field electromagnetic waves. 3. The image recording device described in 3. 5. The cooling means comprises at least one means for bringing a solid, liquid or gas in a third specific temperature range into contact with the recording medium. Reversible thermal recording device. 6. A means for bringing a recording medium into contact with a sublimable solid or a volatile liquid, as the cooling means.
The image recording apparatus according to claim 5, wherein one of them is used.