JPH09254550A - Thermal color developing/erasing type white board and color developing and erasing method thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To form an image having a clear contour and sufficient contrast and to make the marks after erasure inconspicuous without damaging a merit such that no dust is generated at a time of erasure. SOLUTION: A conventional thermal recording agent is changed in transparency by a change of a temp. condition but, by utilizing the color developing and erasing phenomenon accompanied by the change of the temp. condition, a clear contour and sufficient contrast are obtained. Further, the surface hardness of a thermal recording layer is controlled so as to make marks after erasure inconspicuous to set the diameter dimension of the dent generated when a steel ball of 0.5ϕ is pressed to the reversible thermal recording layer 2 formed on a base film under gravity of 300g to 0.1mm or less.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a whiteboard improved by utilizing coloring and decoloring associated with changes in temperature conditions so that dust is not generated during erasing. In the present invention, the whiteboard is a general term for devices having a plate-shaped portion for displaying an image that can be repeatedly shown and erased on a white or light-colored display surface.

[0002]

2. Description of the Related Art Compared with a method of writing on a blackboard with chalk and repeating wiping with a blackboard wipe to erase.
The method of drawing with a marker on a whiteboard and wiping with an eraser to erase the dust has a remarkable effect of reducing the generation of dust, and it is highly necessary to maintain a suitable living environment in hospitals, offices, and It is used in seed factories. However, even in the method of drawing characters, symbols, figures, etc. (hereinafter referred to as image information) on a whiteboard with a marker, some dust is generated when erasing with an eraser. Recently, the level of demand for living environment conservation has increased, and further reduction of the amount of dust is required. Particularly, in a clean room such as a semiconductor manufacturing factory, a pharmaceutical manufacturing factory, a food processing factory, etc., zero dust generation is required. As a material that can meet the above-mentioned requirement for zero dust, a heat-sensitive recording material whose transparency changes with a change in temperature conditions is known (details will be described below), and an electronic blackboard using this is also proposed (Japanese Patent Laid-Open No. Hei 10 (1999) -135242). 7-68992, electronic blackboard using a thermochromic film).

A heat-sensitive recording material generally comprises a support having thereon a heat-sensitive recording layer containing an electron-donating, usually colorless or light-colored dye precursor and an electron-accepting developer as main components.
By heating with a thermal head, a heating pen, a laser beam or the like, a dye precursor and a developer react instantaneously to obtain a recorded image. JP-B-43-4160 and JP-B-45-1.
No. 4039 and the like. In general, such a heat-sensitive recording material cannot erase the portion once an image is formed and return it to the state before the image formation again.
In addition, when recording information, there is no choice but to additionally write in a portion where an image is not formed. For this reason, when the area of the heat-sensitive recording portion is limited, there has been a problem that the recordable information is limited and all necessary information cannot be recorded.

In recent years, a reversible thermosensitive recording material capable of repeating image formation and image erasing has been devised in order to deal with such a problem. For example, Japanese Patent Laid-Open No. 54-119377.
JP-A-63-39377, JP-A-63-4118
No. 6 describes a heat-sensitive recording material composed of a resin base material and organic low-molecular substances dispersed in the resin base material.
However, since this method reversibly changes the transparency of the heat-sensitive recording material by heat energy, the contrast between the image-formed area and the image-unformed area is insufficient. Also, JP-A-50-81157 and JP-A-50-1055.
In the method described in No. 55, since the image to be formed changes in accordance with the ambient temperature, the temperatures at which the image forming state and the erasing state are maintained are different. I can't hold.
Further, JP-A-59-120492 describes a method of maintaining the image forming state and the erasing state by keeping the recording material in the hysteresis temperature region by utilizing the hysteresis characteristic of the coloring component. In the method, a heating source and a cooling source are required for image formation and erasing, and the temperature range in which the image forming state and the erasing state can be maintained is limited to the hysteresis temperature region. It is still insufficient to use.

On the other hand, JP-A-2-188293, JP-A-2-188294, and International Publication No. W090 / 1189.
No. 8 describes a reversible heat-sensitive recording material composed of a leuco dye and a color-developing and decoloring agent for coloring and decoloring the leuco dye by heating. The color-developing agent is an amphoteric compound having an acidic group for coloring the leuco dye and a basic group for decolorizing the colored leuco dye, and has a coloring effect by an acidic group or a decolorizing effect by a basic group by controlling thermal energy. One is preferentially generated to perform color development and decoloration.
Further, JP-A-5-124360 describes a reversible thermosensitive recording material which develops and decolorizes a leuco dye by heating, and an organic phosphoric acid compound as an electron-accepting compound,
Specific phenol compounds such as α-hydroxyaliphatic carboxylic acids, fatty acid dicarboxylic acids, and alkylthiophenols having an aliphatic group having 12 or more carbon atoms, alkyloxyphenols, alkylcarbamoylphenols, and gallic acid alkylesters are exemplified.

[0006] These combinations usually contain a colorless to pale color electron-donating dye precursor and a reversible developer that causes the dye precursor to develop a color by heating and reheats it to decolorize the color-forming substance. In order to form a color-recorded image, it suffices that rapid cooling occurs after heating,
In order to erase the recorded image, the cooling rate after heating should be slow. For example, after heating by an appropriate method, by rapidly cooling by pressing a low-temperature metal block or the like, a colored state can be developed. In addition, when a heating pen, a thermal head, a laser beam, or the like is used for heating for an extremely short time, the material is cooled immediately after the heating is completed, so that the coloring state can be maintained. On the other hand, when heated with an appropriate heat source (thermal head, laser light, heat roll, heat stamp, high frequency heating, radiant heat from a light source such as a tungsten lamp or halogen lamp, hot air, etc.) for a relatively long time, recording Since not only the layer but also the support and the like are heated, even if the heat source is removed, the cooling speed is slow and the state is decolorized. Therefore, even if the same heating temperature and the same heat source are used, the colored state and the decolored state can be arbitrarily expressed by controlling the cooling rate.

However, a reversible sensation containing a colorless or light-colored electron-donating dye precursor and a reversible developer that causes the dye precursor to develop a color upon heating and reheats the color to decolor the color-developing substance. When an image is formed using a thermal pen having a contact between the heating element and the surface of the reversible thermosensitive recording material of 0.5 mm diameter or more, an image is formed depending on the pressure applied by the heating pen during image formation. When the support is deformed or the coating layer is deformed, and then the image is erased, the color trace is visually recognized even though the reflection optical density is the same as the background portion.

[0008]

As described above, even in the prior art, a blackboard device with zero dust was experimentally developed by utilizing transparency and opacity due to changes in temperature conditions. (A) Even after the displayed image information is erased, since the indentation generated on the surface of the recording material due to the writing pressure can be visually recognized, the number of times that repeated use is possible is small, and
(B) Since a transparent line or a transparent point is drawn on an opaque surface, it may be difficult to see it depending on the lighting conditions, and (c) image information displayed for the same reason. Has insufficient contrast, is not easily visible regardless of the illumination condition, and the contour of the displayed image is unclear. There was a problem called. The object of the invention of claim 1 is to produce a thermosensitive coloring that does not generate dust, does not visually show traces of image information after erasing, has sufficient contrast of the displayed image, and allows the outline of the displayed image to be clearly visible.
The purpose is to provide a heat-erasable whiteboard.

The object of the invention of claim 2 is, in addition to the object of the invention of claim 1, easy to write with a hot pen, and
It is an object to provide a heat-sensitive color-developing / heat-erasing type whiteboard in which the temperature control for developing and erasing is easy. The object of the invention of claim 3 is, in addition to the object of the invention of claim 2, of a heat-sensitive coloring / heat-erasable type capable of displaying and storing display image information temporarily and displaying image information different from the above. It is to provide a whiteboard. The object of the invention of claim 4 is, in addition to the object of the invention of claim 3, a heat-sensitive coloring / heat-erasable whiteboard capable of storing displayed image information semipermanently or remotely recognizing it. Is to provide. The object of the invention of claim 5 is, in addition to the objects of the inventions of claims 3 and 4, to provide a heat-sensitive color-developing / heat-erasable whiteboard capable of semi-automatically erasing displayed image information. The object of the invention of claim 6 is, in addition to the objects of claims 3-5, to provide a heat-sensitive coloring / heat-erasable whiteboard capable of displaying image information semi-automatically and / or remotely. That is.

The object of the invention of claim 7 is, in addition to the object of the invention of claims 3-5, to provide a heat-sensitive coloring / heat-erasable whiteboard which can easily perform handwritten display. The object of the invention of claim 8 and the object of the invention of claim 9 are, in addition to the objects of the invention of claim 1, 2 or 7 respectively, that image deletion by manual operation can be performed quickly, easily and completely. It is to provide a heat-sensitive coloring / heat-erasing type whiteboard. An object of the invention of claim 10 is, in addition to the objects of the inventions of claims 1 to 9, is to provide a heat-sensitive color-developing / thermo-erasing whiteboard in which the durability of the reversible thermosensitive recording layer is improved. . The object of the invention of claim 11 is, in addition to the object of the invention of claim 10, that the hardness of the protective layer, which is a member indispensable for the constitution of the invention of claim 10, can be easily controlled, and a protective layer having an appropriate hardness can be provided. It is an object of the present invention to provide a heat-sensitive coloring / heat-sensitive coloring whiteboard that can be reliably configured. The object of the invention of claim 12 is claim 1
In addition to the object of the invention of Nos. 0 and 11, there is provided a heat-sensitive coloring / heat-erasable whiteboard capable of easily controlling the surface roughness of the protective layer and forming a protective layer having an appropriate surface roughness. Is. The object of the invention of claim 13 is to easily control the friction coefficient when handwriting image information with a hot pen, to have an appropriate friction coefficient, and to surely obtain comfortable feeling and writing comfort and easy to use. It is to provide a heat sensitive color development / heat decolorization type whiteboard.

The object of the 14th aspect of the invention is, in addition to the objects of the 1st to 9th aspects, that the reversible thermosensitive recording layer has high durability and is of a thermosensitive coloring / erasing type suitable for industrial production. It is to provide a whiteboard. The object of the invention of claim 15 is, in addition to the objects of the inventions of claims 10-14, to balance the improvement of the durability of the reversible thermosensitive recording layer and the maintenance of the sensitivity of the reversible thermosensitive recording layer to the emission and decolorization reaction. Heat-sensitive coloring
The purpose is to provide a heat-erasable whiteboard.

It is an object of the invention of claim 16 to provide a method of producing and erasing clearly by repeating coloring and erasing without generating dust from the whiteboard. In addition to the object of the invention of claim 17, the object of the invention of claim 17 is that the whiteboard sheet of the part on which the image information is colored is temporarily stored and stored, and the whiteboard sheet of the other part is described above. It is to provide a method of erasing and erasing a whiteboard that can cause different image information to be developed.

In addition to the object of the sixteenth aspect of the present invention, the object of the eighteenth aspect is to generate a whiteboard capable of semi-automatically or automatically erasing the colored image information.
It is to provide an erasing method.

The object of the invention of claim 19 is, in addition to the object of the invention of claim 18, that the colored image information can be semipermanently stored or can be remotely recognized, and the whiteboard can be colored or erased. Is to provide a method. Claim 2
The object of the invention of No. 0 is, in addition to the object of the invention of Claim 19, to provide a method of erasing and erasing a whiteboard by which image information can be semi-automatically or automatically developed.

[0015]

The basic principle of the present invention created to achieve the above object will be described. In order to achieve the object of these series of inventions, first, a whiteboard sheet using a reversible thermosensitive recording material that does not generate dust is used as a base material, which is improved so that the contrast is high and the contour is clear. It is necessary to suppress the deformation of the support and the coating layer so that the trace of color development cannot be visually recognized when the color is developed with a hot pen and erased with the heating block without causing the deformation of the support or the coating layer.

The inventors of the present invention have conducted researches to solve this problem, and as a result, on at least one surface of a support, a colorless or light-colored electron-donating dye precursor is allowed to develop a color by heating. A reversible thermosensitive recording material provided with a reversible thermosensitive recording layer containing a reversible color developing agent that reheats and decolorizes the reversible thermosensitive recording material, and a single heating element capable of coloring the reversible thermosensitive recording material by heating. In a recording system using a device, the surface roughness Rz (JIS B
10-point average roughness specified in O6O1) is 0.5 to 5μ
m, and 0.5 m on the surface of the reversible thermosensitive recording material.
The present invention provides a reversible thermosensitive recording material, characterized in that the reversible thermosensitive recording material has a deformation of not exceeding 0.1 mm when a stainless steel ball of m diameter is pressed with a load of 300 g. Solved the problem.

In the hot pen used in the present invention, the contact member between the heating element and the surface of the reversible thermosensitive recording material preferably has a diameter of 0.5 mm or more, and a metal material, an inorganic material or an organic material having a melting point of 200 ° C. or more. The material is used and has a suitable heat source (micro heating element, electric heater, high frequency heating, induction heating or radiant heat from a light source such as a tungsten lamp or a halogen lamp). As will be described in detail later, the color reaction appears when it is quenched after heating. When an arbitrary point on the surface of the reversible thermosensitive recording material is considered, when the tip of the heating pen slides over the virtual point and passes by, the virtual point is suddenly heated and then allowed to cool. But,
If the area to be heated is linear and its area is very small, the above-mentioned cooling is performed relatively quickly, so that the condition that color develops easily appears. However, in this case, if there is a cooling means such as a member having an endothermic function being in close contact with the back side of the layer of the reversible thermosensitive recording material, the color formation is more surely performed.

The heating block (which may be a thick plate) used for erasing has a larger contact portion between the heating element and the reversible thermosensitive recording material than the heating pen, and has an appropriate heat source inside or outside (small heating element or That aggregate, high-frequency heating, electric heater, induction heating and radiant heat from a light source such as a tungsten lamp or a halogen lamp, hot air, etc.),
The reversible thermosensitive recording material is heated or erased by pressing or sliding it on the surface of the reversible thermosensitive recording material including the colored portion. As will be described in detail later, the decoloring reaction appears when the material is heated and then gradually cooled. When the area having a certain area on the surface of the reversible thermosensitive recording material is heated by the surface contact of the high temperature member, the temperature is relatively gradually decreased after the high temperature member is separated, so that the condition easily fading appears. To be done.
However, in this case, if there is a heat retaining / slow cooling means such as a member having a heat storage function being in close contact with the back side of the reversible thermosensitive recording material, the decoloring is performed more reliably.

In the reversible thermosensitive recording material of the present invention, in order to form a color-recorded image, rapid cooling may occur after heating, and in order to decolor the recorded image, the cooling rate after heating is set. It's good if it's late. Therefore, even if the same heating temperature and / or the same heat source is used, the colored state and the decolored state can be arbitrarily expressed by controlling the cooling rate.

The composition and properties of the reversible thermosensitive recording material which is the basis of the series of inventions according to the present application will be described below. The reversible thermosensitive recording material of the present invention comprises 300 g of a 0.5 mm diameter stainless steel ball. When the pressure is applied with a load, the reversible thermosensitive recording material is deformed by a pressure of 0.1 m.
It does not exceed m. Deformation due to pressing is 0.1 mm
Even if the reversible thermosensitive recording material as described above is colored with a hot pen and then erased with a heating block, there is no difference in the reflection optical density between the background and the colored traces, but the traces of color development are visible. I will end up. This is because the difference in light reflection due to the deformation of the support and the coating layer can be visually recognized. The surface roughness Rz of the reversible thermosensitive recording material of the present invention is 0.5 to 5 μm. That is, when a stainless steel ball having a diameter of 0.5 mm was pressed onto the support of the reversible thermosensitive recording material with a load of 300 g, the reversible thermosensitive recording material was deformed by a pressure of 0.1.
Even when it does not exceed Rmm, when the reversible thermosensitive recording material is produced using the support, Rz is 0.
When it is less than 5, even if the color is erased by the heating block after the color is developed with the hot pen, the trace of the color is visible even though there is no difference in the reflection optical density between the background portion and the erased portion. This is because when the surface roughness Rz is 0.5 μm or less, a slight breakage of the coating layer or / or a change in the surface roughness that occurs when writing with a hot pen is emphasized and can be visually recognized as a change in light reflection. Further, even if the surface roughness Rz is 5 μm or more, a slight coating layer breakage or / or a change in the surface roughness becomes remarkable, which can be visually recognized as a change in light reflection. In any case, since the coating layer is destroyed or / or the surface roughness is changed, the reversible thermosensitive recording material appears to have been damaged by a small number of times when repeatedly developed / decolored, That is, it seems that the number of times of repeated use has decreased.

According to the present invention, the surface roughness Rz is 0.5 to 5 μm.
When it is in the range of m, a slight breakage of the coating layer and / or a change in the surface roughness are inconspicuous, that is, a change in the light reflection of the trace of color development is not visible at all or is difficult to see. Therefore, even when the color is repeatedly developed / erased, the reversible thermosensitive recording material does not seem to be damaged even when the number of times is increased, that is, the number of times of repeated use is increased.

Further, when the surface roughness Rz is 0.5 μm or less, there is a drawback that the surface has gloss and is difficult to read, and when writing with a hot pen, it is slippery and difficult to write. Surface roughness R
If z is 5 μm or more, it is difficult to write when writing with a hot pen, and the contact area with the hot pen is small, so uniform coloration does not occur, and when drawing a line, it becomes a broken line There is.

According to the present invention, the surface roughness Rz is 0.5 to 5 μm.
When it is in the range of m, it is easy to read because of its moderate surface gloss and easy to write with a hot pen because of its moderate roughness. Further, since the contact area with the hot pen is appropriate, uniform color development is possible.

The reversible thermosensitive recording material of the present invention comprises at least a protective layer, a reversible thermosensitive coloring layer and a support.

The protective layer used in the reversible thermosensitive recording material of the present invention repeatedly writes and erases an image by heating with a heating pen followed by heating with a heat block, and prevents deterioration of the reversible thermosensitive recording layer. Therefore, a protective layer is provided on the reversible thermosensitive recording layer. Materials for forming the protective layer include water-soluble polymers, latexes, and polymerizable compounds. Examples thereof include polyurethane resin, polyester resin, epoxy resin, melamine resin, polyvinyl alcohol, nitrocellulose, methacrylic acid ester, acrylic acid oligomer, acrylic acid ester oligomer and the like. If necessary, a crosslinking agent such as an epoxy compound, a urea derivative, or a vinyl compound, and a curing agent such as a phosphoric acid type, a sulfonic acid type, a polyamide type, and an amine type can be added. Further, the protective layer may contain a pigment in order to adjust the surface roughness Rz of the reversible thermosensitive recording material to 0.5 to 5 μm. The pigment here may be either an organic pigment or an inorganic pigment. For example, heavy calcium carbonate, light calcium carbonate, barium sulfate, kaolin, calcined kaolin, talc, aluminum hydroxide, aluminum silicate, magnesium oxide, magnesium carbonate,
Silica gel, colloidal silica, alumina sol, magnesium sulfate, zinc oxide, activated clay, finely divided silicic acid, titanium oxide, calcium silicate, polyolefin resin, polystyrene resin, urea-formaldehyde resin, styrene-acrylic resin, acrylic resin, silicone resin, color pigment, etc. However, the present invention is not limited to these. These pigments can be used alone or in combination of two or more kinds.

If desired, a lubricant may be added to the protective layer. Lubricants are mainly waxes such as stearic acid amide, oleic acid amide, lauric acid amide, ethylenebisstearic acid amide, methylenebisstearic acid amide, methylolstearic acid amide,
Examples thereof include paraffin wax, polyethylene wax, higher alcohol, higher fatty acid, higher fatty acid ester, and silicone compound, but are not limited thereto. The coating amount of the protective layer is desired to be thinner for the purpose of avoiding heat blocking, and is preferably 0.5 to 5 g / m ² . When it is less than this range, the function as a good protective layer does not appear, and when it is more than this range, the thermal sensitivity is deteriorated. The method for forming the protective layer constituting the reversible thermosensitive recording material of the present invention is not particularly limited, and it can be formed by a conventional method. For example, it is possible to use a smearing device such as an air knife coater, a blade coater, a bar coater, a curtain coater, and various printing machines such as planographic, relief, intaglio, flexo, gravure, and screen systems. Further, in addition to the usual drying step, the protective layer can be held by UV irradiation, electron beam irradiation, heating or the like, if necessary. Further, regardless of the formation of the above-mentioned protective layer, like polyethylene, polyethylene terephthalate, etc.,
It is also possible to form a protective layer on the reversible thermosensitive recording layer by a method such as pasting in the state of a film capable of transmitting light.

The usually colorless or light-colored electron-donating dye precursor used in the present invention is typified by those generally used for pressure-sensitive recording paper and heat-sensitive recording paper, but is not particularly limited. Specific examples include the followings, but the present invention is not limited thereto. (1) Triarylmethane compound 3,3-bis (p-dimethylaminophenyl) -6-dimethylaminophthalide (crystal violet lactone), 3,3-bis (p-dimethylaminophenyl) phthalide, 3- ( p-dimethylaminophenyl) -3-
(1,2-dimethylindol-3-yl) phthalide,
3- (p-dimethylaminophenyl) -3- (2-methylindol-3-yl) phthalide, 3- (p-dimethylaminophenyl) -3- (2-phenylindole-
3-yl) phthalide, 3,3-bis (1,2-dimethylindol-3-yl) -5-dimethylaminophthalide, 3,3-bis (1,2-dimethylindole-3-
Yl) -6-dimethylaminophthalide, 3,3-bis (9-ethylcarbazol-3-yl) -5-dimethylaminophthalide, 3,3-bis (2-phenylindol-3-yl) -5 -Dimethylaminophthalide, 3-p
-Dimethylaminophenyl-3- (1-methylpyrrol-2-yl) -6-dimethylaminophthalide, 3- (4
-Diethylamino-2-ethoxyphenyl) -3- (1
-Ethyl-2-methylindol-3-yl) -4-azaphthalide, 3,3 '-(4'-diethylamino-2-
(Ethoxyphenyl) -4-azaphthalide and the like, (2) diphenylmethane compound 4,4'-bis (dimethylaminophenyl) benzhydrylbenzyl ether, N-chlorophenylleuco auramine, N-2,4,5-trichlorophenyl (3) Xanthene compound Rhodamine B anilinolactam, Rhodamine B-p-chloroanilinolactam, 3-diethylamino-7-dibenzylaminofluorane, 3-diethylamino-7-octylaminofluorane, 3-diethylamino-7-phenylfluorane, 3-diethylamino-7-chlorofluorane, 3-diethylamino-6-chloro-7-methylfluorane, 3-diethylamino-7- (3,4-dichloroanilino) fluorane , 3-diethylamino-7
-(2-chloroanilino) fluorane, 3-diethylamino-6-methyl-7-anilinofluorane, 3- (N
-Ethyl) tolylamino-6-methyl-7-anilinofluoran, 3-piperidino-6-methyl-7-anilinofluoran, 3- (N-ethyl) tolylamino-6-methyl-7-phenethylfluoran, 3-diethylamino-7- (4-nitroanilino) fluoran, 3-dibutylamino-6-methyl-7-anilinofluoran, 3-
(N-Methyl) propylamino-6-methyl-7-anilinofluorane, 3- (N-ethyl) isoamylamino-6-methyl-7-anilinofluorane, 3- (N-methyl) cyclohexylamino- 6-methyl-7-anilinofluorane, 3- (N-ethyl) tetrahydrofurylamino-6-methyl-7-anilinofluorane, etc. (4) thiazine compound benzoylleuco methylene blue, p-nitrobenzoyl leuco methylene blue Etc. (5) Spiro compound 3-methylspirodinaphthopyran, 3-ethylspirodinaphthopyran, 3,3′-dichlorospirodinaphthopyran, 3-benzylspirodinaphthopyran, 3-methylnaphtho (3-methoxy Benzo) spiropyran, 3-propylspirobenzopyran and the like.

On the other hand, the reversible color developer used in the present invention is preferably an electron-accepting compound, for example, JP-A-2-
188293, JP-A-2-188294,
International Publication No. WO9O / 11898, a developing and reducing agent having an acidic group for coloring a leuco dye and a basic group for decoloring, an organic phosphonic acid compound described in JP-A-5-124360, and α-hydroxyaliphatic. Examples thereof include carboxylic acids, fatty acid dicarboxylic acids, and alkylthiophenols having an aliphatic group having 12 or more carbon atoms, alkyloxyphenols, alkylcarbamoylphenols, gallic acid alkylesters, and the like. There is no particular limitation as long as it is an agent. Further, those represented by the following general formula 1 are particularly preferably used in terms of color density and decoloring property. Can be used in inventions. The method of synthesizing the compound of formula 1 is described in Japanese Patent Application Laid-Open No. 6-21095 by the present applicant.
4, Japanese Patent Application No. 5-160547, Japanese Patent Application No. 5-25
6825, Japanese Patent Application No. 5-317555, Japanese Patent Application 5-3
28101 and Japanese Patent Application No. 6-10310.

[0029]

Embedded image

(In the formula 1, n is an integer from 1 to 3, i, j
And k each represent 0 or 1. However, when i is 1,
j indicates 1. R ¹ and R ² represent a divalent hydrocarbon group having 1 to 18 carbon atoms, and R ³ represents a hydrocarbon group having 1 to 24 carbon atoms. X ¹ represents a divalent group having at least one -CONH- bond, and X ² represents a divalent group having at least one -CONH- bond, an oxygen atom or a sulfur atom).

In the compound represented by the above formula ¹ , R ¹ and R ² are divalent hydrocarbon groups having 1 to 18 carbon atoms,
The group may contain an aromatic ring, or may have only an aromatic ring. Specific examples of the divalent group having at least one —CONH— bond represented by X ¹ and X ² include amide (—CONH—, —NHCO—), urea (—NHCON).
H-), urethane (-NHCOO-, -OCONH
-), Diacylamine (-CONHCO-), diacylhydrazide (-CONHNHCO-), oxalic acid diamide (-NHCOCONH-), acylurea (-CONH)
CONH-, -NHCONHCO-), 3-acylcarbazide ester (-CONHNHCOO-), semicarbazide (-NHCONHNH-, -NHNHCONH)
-), Acyl semicarbazide (-CONHNHCONH
-, - NHCONHNHCO-), diacyl aminomethane (-CONHCH ₂ NHCO -), 1- acylamino-1- Ureidometan (-CONHCH ₂ NHCONH
-, - NHCONHCH ₂ NHCO-), a group such as malonamide (-NHCOCH ₂ CONH-). The compound represented by the general formula 1 is an electron-accepting compound and has a specific decoloring effect, that is, a reversible effect, even though it has the ability to color the leuco dye. In addition,
Such electron-accepting compounds used in ordinary heat-sensitive recording materials, that is, 2,2-bis (4-hydroxyphenyl) propane, bis (4-hydroxyphenyl) sulfone, benzyl 4-hydroxybenzoate, etc. No effect is seen. Specific examples of the electron-accepting compound represented by the general formula 1 are shown below, but the present invention is not limited thereto.

For example, in Formula 1, i = O / j = O / k =
As the compound which is O, 4'-hydroxyhexadecaneanilide, N-octadecyl-4-hydroxybenzamide, N- (4-hydroxyphenyl) -N'-octadecylurea, N- (4-hydroxybenzo) -N'-
Octadecanohydrazide, N- (3,4-dihydroxyphenyl-N'-octadecyloxamide, etc.
In the above, a compound in which i = O / j = 1 / k = O is N
-[2- (4-hydroxyphenyl) ethyl] -N'-
Octadecyl urea, N- [3- (4-hydroxyphenyl) propiono] -N'-octadecanohydrazide, N
-[3- (4-hydroxyphenyl) propiono]-
N′-docosanohydrazide, 1- [3- (4-hydroxyphenyl) propionyl] amino-1-octadecanoylaminomethane, 1- (4-hydroxyphenylacetyl) -4-octadecylsemicarbazide and the like, Formula 1
In the above, a compound in which i = 1 / j = 1 / k = O is N
-Hexadecyl- (4-hydroxyphenylthio) acetamide, N- [2- (4-hydroxyphenylthio)]
Ethyl] -N'-octadecyl urea, N- [4-hydroxyphenylthio) aceto-N'-docosanohydrazide, N- [11- (4-hydroxyphenylthio) undecano] -N'-decanohydrazide, N- [2- (4-
Hydroxyphenylthio) ethyl] -N'-octadecyloxamide, N- [4- (4-hydroxyphenylthio) phenyl] -N'-octadecyloxamide, N-
[4- (4-hydroxyphenylthiomethyl) benzo]
-N'-docosanohydrazide, etc. in Formula 1, i = O / j
Examples of the compound having ═O / k = 1 include N- (4-hydroxyphenyl) -3-dodecylthiopropanamide, N
-(4-hydroxyphenyl) -N'-3-octadecylthiopropylurea, 4-hydroxy-4'-octadecyloxybenzanilide, 4-hydroxy-4'-dodecylthiobenzanilide, 2- (4-octadecanoylamino) Phenyl) -4'-hydroxyacetanilide, 2- [4- (N'-octadecylureido) phenyl] -4'-hydroxyacetanilide, etc.
As a compound in which i = O / j = 1 / k = 1, N-
[3- (4-hydroxyphenyl) propiono] -N '
-(3-dodecylthiopropiono) hydrazide, N-
[3- (3,4-dihydroxyphenyl) propiono]
Examples of compounds having i = 1 / j = 1 / k = 1 in Formula 1 such as —N ′-(11-decylthioundecano) hydrazide include N- [3- (4-hydroxyphenylthio) propiono. ] -N '-(3-octadecylthiopropiono) hydrazide, N- [11- (3,4,5-trihydroxyphenylthio) undecano] -N'-(11-octadecylthioundecano) hydrazide and the like. To be

These reversible developers may be used alone or in admixture of two or more, and the amount of the reversible developer based on the dye precursor is 5-5000% by weight, preferably 10-. It is 3000% by weight. Further, the binder may be used in combination with the reversible developer and the dye precursor for the purpose of improving the strength of the reversible thermosensitive recording layer. Specific examples of the binder, starches, hydroxyethyl cellulose, methyl cellulose, carboxymethyl cellulose, gelatin, casein, polyvinyl alcohol,
Modified polyvinyl alcohol, sodium polyacrylate, acrylamide / acrylate copolymer, acrylamide / acrylate / methacrylic acid terpolymer, alkali salt of styrene / maleic anhydride copolymer, ethylene / Water-soluble polymers such as alkali salts of maleic anhydride copolymer, polyvinyl acetate, polyurethane, polyacrylate, styrene / butadiene copolymer,
Latexes such as acrylonitrile / butadiene copolymer, methyl acrylate / butadiene copolymer, ethylene / vinyl acetate copolymer, and the like are included, but are not limited thereto.

A pigment may be used in combination with the binder for the purpose of improving durability and adjusting color tone.
The pigment here may be either an organic pigment or an inorganic pigment. For example, heavy calcium carbonate, light calcium carbonate, barium sulfate, kaolin, calcined kaolin, talc,
Aluminum hydroxide, aluminum silicate, magnesium oxide, magnesium carbonate, silica gel, colloidal silica, alumina sol, magnesium sulfate, zinc oxide, activated clay, finely divided silicic acid, titanium oxide, calcium silicate, polyolefin resin, polystyrene resin, urea-formaldehyde resin, styrene -Acrylic resins, acrylic resins, silicone resins, color pigments, etc. are mentioned, but not limited to these. These pigments may be used alone or in 2
More than one species can be used together. Further, a heat-fusible substance may be contained in the reversible thermosensitive recording layer as an additive for controlling the color developing sensitivity and the decoloring temperature of the reversible thermosensitive recording layer.
Those having a melting point of 60 ° C to 200 ° C are preferred, and those having a melting point of 80 ° C to 180 ° C are particularly preferred. A sensitizer used in general thermosensitive recording paper can also be used. For example, waxes such as N-hydroxymethylstearic acid amide, stearic acid amide, and palmitic acid amide; naphthol derivatives such as 2-benzyloxynaphthalene; biphenyl derivatives such as p-benzylbiphenyl and 4-allyloxybiphenyl; -Bis (3
-Methylphenoxy) ethane, 2,2'-bis (4-methoxyphenoxy) diethyl ether, bis (4-methoxyphenyl) ether and other polyether compounds, diphenyl carbonate, dibenzyl oxalate, bis (p-oxalate)
Carbonic acid such as methylbenzyl) ester or an oxalic acid diester derivative may be added in combination, but the addition is not limited thereto.

The support used in the reversible thermosensitive recording material of the present invention includes paper, coated paper, various non-woven fabrics, woven fabrics, synthetic resin films, synthetic resin laminated papers, synthetic papers, metal foils, glass, etc., or A composite sheet combining these can be optionally used according to the purpose, and further,
It may be transparent, semi-transparent or opaque,
It is not limited to these. The thickness of the support is not particularly limited as long as it can withstand repeated use, but is 20 to 1300 μm, preferably 40 to 100 μm.
It is about 0 μm. In each case, at least 3 mm of stainless steel balls with a diameter of 0.5 mm are provided on the surface of the support.
When pressed with a load of 00 g, it is desirable that the deformation due to the pressing of the support does not exceed 0.1 mm. In the present invention, an undercoat layer may be interposed between the support and the reversible thermosensitive recording layer, if desired. The undercoat layer is provided for the purpose of improving the heat insulating property, improving the adhesiveness between the support and the recording layer, and preventing the absorption of the heat-melting substance by the support when heat is applied during image formation and image erasing. . The resin used for the undercoat layer is not particularly limited, but various conventionally known water-soluble and water-insoluble polymers are used. In the present invention, an intermediate layer may be provided on the reversible thermosensitive recording layer. The resin used for the intermediate layer is not particularly limited, but various conventionally known water-soluble and water-insoluble polymers are used. Specific examples of the water-soluble polymer include polyvinyl alcohol, modified polyvinyl alcohol, starch and its derivatives, methylcellulose or cellulose derivatives such as methoxycellulose or vidroxyethylcellulose, casein, gelatin, polyvinylpyrrolidone, styrene-maleic anhydride. Acid copolymer, diisobutylene-maleic anhydride copolymer, polyacrylamide, modified polyacrylamide, methyl vinyl ether-maleic anhydride copolymer, carboxy-modified polyethylene, polyvinyl alcohol-acryloamide copolymer, melamine-formaldehyde resin, urea -Formaldehyde resin and the like. These water-soluble polymers are used in the form of aqueous solutions.

Specific examples of the above non-aqueous polymer include:
Polyvinyl acetate, polyurethane, styrene-butadiene copolymer, styrene-butadiene-acrylic copolymer, polyacrylic acid, polyacrylic acid ester, vinyl chloride-vinyl acetate copolymer, polybutyl methacrylate, ethylene-vinyl acetate copolymer Examples thereof include polymers. These water-insoluble polymers are used in the form of aqueous emulsion. The polymers may be used alone or as a mixture, and if necessary, a curing agent may be added to cure the resin.
Further, a pigment may be used in combination with the above-mentioned polymer for the purpose of improving durability and adhesiveness. The pigment here may be either an organic pigment or an inorganic pigment. For example, heavy calcium carbonate, light calcium carbonate, barium sulfate, kaolin, calcined kaolin, talc, aluminum hydroxide, aluminum silicate, magnesium oxide, magnesium carbonate, silica gel, colloidal silica, alumina sol, magnesium sulfate, zinc oxide, activated clay, Fine powder silicic acid, titanium oxide, calcium silicate, polyolefin resin, polystyrene resin, urea-formaldehyde resin, styrene-
Examples thereof include acrylic resins, acrylic resins, silicone resins, and color pigments, but are not limited to these. These pigments can be used alone or in combination of two or more kinds.

The method for forming each layer other than the protective layer constituting the reversible thermosensitive recording material of the present invention on the support is not particularly limited, and it can be formed by a conventional method. For example, it is possible to use a smearing device such as an air knife coater, a blade coater, a bar coater, a curtain coater, and various printing machines such as planographic, letterpress, intaglio, flexo, gravure, screen, and hot melt systems. Further, in addition to the usual drying step, each layer can be held by irradiation with ultraviolet rays, irradiation with electron beams, heating or the like. By these methods, it is possible to smear and print one layer at a time or multiple layers at the same time.

Based on the principle described above, as a specific structure for achieving the above-mentioned object, the heat-sensitive coloring / heat-erasing type whiteboard according to the present invention is provided on the surface of a base film which is a support. Reversible recording containing "a usually colorless to light-colored electron-donating dye precursor" and "a reversible developer that causes the dye precursor to develop color by heating and cooling, and decolorizes the color by reheating and cooling" A whiteboard sheet formed with a reversible thermosensitive recording layer made of an agent, and a high temperature convex curved surface which is brought into point contact with the reversible thermosensitive recording layer, and the reversible thermosensitive recording layer is formed by contact of the convex curved surface. A member for description that locally heats up and develops color, and a high-temperature flat surface or a high-temperature cylindrical surface that is brought into surface contact or line contact with the reversible thermosensitive recording layer, and has contact with the flat surface or the cylindrical surface. And comprising a member for erasing to be decolorized allowed warm to specific areas of the reversible thermosensitive recording layer I and surface roughness Rz of the reversible thermosensitive recording layer is 0.
When the surface of the reversible thermosensitive recording layer is in contact with a stainless steel ball having a diameter of 0.5 mm and a load of 300 g is applied to the surface of the reversible thermosensitive recording layer, the diameter dimension of the indentation caused by the plastic deformation of the surface is It is characterized by not exceeding 0.1 mm.

In addition, the whiteboard according to the present invention,
Decoloring method, "usually colorless or light-colored electron-donating dye precursor" and "a reversible developer that causes the dye precursor to develop color by heating / quenching and recolors by reheating / slow cooling" A reversible thermosensitive recording layer comprising a reversible recording agent containing is formed on the base film, a protective layer is formed on the surface of the reversible thermosensitive recording layer, and a protective agent is added to the protective layer in advance to carry out the protection. The hardness of the layer is controlled, the reversible thermosensitive recording layer is pressed against the backboard with a hot pen in a state where the base film is superposed on a back boat, and locally heated and rapidly cooled to color the local portion, and heat. A plate is brought into contact with the reversible thermosensitive recording layer, or a heat roller is rolled while being brought into contact with the reversible thermosensitive recording layer, whereby the reversible thermosensitive recording layer is heated and gradually cooled to be erased. And it features. In the means described above, “point contact” does not mean strictly in terms of three-dimensional geometry, but means that the contact area is very narrow. Similarly, "line contact" means that the contact width is very narrow. Further, the "planar surface which is brought into surface contact" means "a substantially flat surface which is brought into contact in a state close to surface contact". The "heat plate" means a member having such a surface, and may be a plate-shaped or block-shaped member made of a heat conductive material and provided with a heating means.

According to the heat-sensitive coloring / heat-erasing type whiteboard according to the present invention described above (claim 1), the transparency does not change depending on the temperature condition as in the conventional example, but the reversible heat-sensitive recording is performed. As the layer develops and erases color, not only does it not generate dust during decolorization,
The contrast of the image information shown by color development is sufficient, and its contour is clear. Moreover, since the hardness of the reversible thermosensitive recording layer is properly set in relation to the writing pressure of the hot pen, the indentation left after the color is erased is not visually recognized, and the number of times of repeated use is large.

In carrying out the whiteboard of the present invention, when a backboard having a large heat capacity is provided on the back surface of the whiteboard sheet (claim 2), the reversible thermosensitive recording layer absorbs heat from the portion heated by the hot pen. Color development can be promoted, and heat of the portion heated by the erasing member can be stored to promote decolorization. When carrying out the whiteboard of the present invention, when the whiteboard sheet is formed into an endless ring and is wound around two vertical rollers and rotated (claim 3),
Colored image information can be temporarily stored and stored, or it can be taken out again and posted, and in addition, the image information different from the above is displayed in the margin of the whiteboard sheet during the above storage and storage. It can also be shown.

When the whiteboard of the present invention is carried out, the whiteboard sheet is formed into an endless ring shape so that it can be wound around two rollers to be fed and operated, and at the same time, an illumination means, a line image sensor, and a projection lens. When the system is provided (Claim 4), the image information on the whiteboard can be detected as an electric signal, so that the printing means can be operated and the detection signal can be transmitted to a remote place. . When the whiteboard of the present invention is carried out, the whiteboard sheet is configured as an endless ring so that the whiteboard sheet can be wound around two rollers to be fed and operated, and a heater for erasing can be provided by facing the whiteboard sheet. If provided (Claim 5), the image information showing the color development can be erased automatically or semi-automatically.

When carrying out the whiteboard of the present invention, the whiteboard sheet is formed into an endless ring shape and 2
A desired type of image information can be automatically or semi-automatically colored by wrapping around a book roller so that it can be fed, and by providing a heat type dot printer facing the whiteboard sheet (Claim 6). be able to.

When the whiteboard of the present invention is implemented, by using a heat rod (heat pen) provided with an electric heater and a power supply means (claim 7), the operation of displaying the image information by handwriting the color is facilitated. It can be performed reliably. When the whiteboard of the present invention is put into practice, an eraser comprising a heat plate provided with an electric heater, a power feeding means and a handle is used (claim 8), whereby a manual erasing operation can be carried out quickly and easily.
When the whiteboard of the present invention is put into practice, an eraser composed of an electric heater, a power feeding means, and a heat roller provided with a handle is used (claim 9), and a manual decoloring operation can be easily performed with a light force.

When carrying out the whiteboard of the present invention, a plurality of types of reversible recording agents which develop different color tones under different temperature conditions are used, and a plurality of reversible recording agents adapted to the temperature conditions for developing each reversible recording agent are used. If an electric heating pen is provided, it is possible to display multi-colored images and display abundant image information. When carrying out the whiteboard of the present invention, while using a plurality of types of reversible recording agents that develop different color tones under different temperature conditions,
If the temperature of one electric heating pen can be adjusted according to the color development temperature condition of each reversible recording agent, multicolor display can be performed with one electric heating pen.

When the whiteboard of the present invention is carried out, a protective layer is formed on the surface of the reversible thermosensitive recording layer (claim 10) to prevent deterioration of the reversible thermosensitive recording layer due to repeated use. When the hardness is controlled by adding a curing agent to the protective layer (claim 11), the function of making the decolored traces inconspicuous can be surely exhibited. When a pigment is added to the protective layer to control the surface roughness (Claim 12), traces after erasing are made inconspicuous, the gloss of the marking surface is moderated, and writing comfort with a hot pen is adjusted. can do. The writing comfort can be adjusted more precisely by adding a lubricant to the protective layer (claim 13). When the protective layer is formed by sticking a transparent film on the surface of the reversible thermosensitive recording layer (claim 14), a thermosensitive coloring / thermoerasable whiteboard can be industrially produced at low cost. . The thickness of the protective layer is 0.5 to 5 g / m.
^When set to ² (claim 15), the number of times the reversible thermosensitive recording layer can be repeatedly used can be increased without unnecessarily hindering the sensitivity of the thermosensitive reaction.

According to the method for producing and erasing the heat-sensitive color-developing / thermo-discoloring type whiteboard according to the present invention (claim 16), it is a phenomenon such as color-developing / erasing which is easy to visually recognize, not a change in transparency as in the conventional example. You can repeat the operation of showing and erasing image information by using
No dust is generated during erasing and no traces are noticeable after erasing. In addition, the boundary between the colored portion and the non-colored portion is clear, and sufficient contrast can be obtained.

When the coloring and decoloring method of the present invention is carried out, a pigment is added to the reversible recording agent to control the surface roughness, so that the gloss of the image information can be moderated so that the image information can be easily recognized. When carrying out the coloring and erasing method of the present invention, the whiteboard sheet is formed into an endless annular shape, and when the endless annular whiteboard sheet is fed and operated (Claim 17), color development is performed to display the image information. Can be temporarily stored and stored, and can be quickly and easily taken out as needed. When an eraser is provided so as to face the endless annular whiteboard sheet (claim 18), it is possible to automatically erase the image information of which color development is shown. Further, when a line image sensor and a projection lens system are provided so as to face the endless annular whiteboard sheet (claim 19), the image information represented by color development is converted into an electric signal to semipermanently. Can be recorded and sent. Further, when a heat rod type dot printer is provided so as to face the whiteboard sheet (claim 20), electric signals can be converted into image information. When carrying out the coloring and erasing method of the present invention,
Multi-color image information can be displayed by using a plurality of types of reversible recording agents having different color tones and color development temperature conditions and using a hot pen which gives each color development temperature condition.

[0049]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, embodiments of the present invention will be described with reference to FIGS.

FIG. 1 is shown to explain the principle of the basic structural function of the present invention. (A) is a perspective view of a whiteboard main body partly cut away, (B). FIG. 3 is an external perspective view of a hot pen, FIG. 3C is an external perspective view of an eraser, and FIG. 3D is an external perspective view of an eraser different from the above. The reversible thermosensitive recording layer 2 is formed on at least one surface of the base film 1, and the protective layer 3 is laminated so as to cover the reversible thermosensitive recording layer 2 to form the whiteboard sheet 8. The whiteboard sheet 1 shown in FIG. 1 is drawn in an enlarged manner in the thickness direction. The reversible thermosensitive recording layer 2 includes a "usually colorless or light-colored electron-donating dye precursor" and "a reversible developer that causes the dye precursor to develop color by heating / quenching, and decolorizes the color former by reheating / slow cooling. It is composed of a reversible recording agent containing "colorant",
As to the specific composition thereof, as described above in the section “Means for Solving the Problem” (hereinafter, abbreviated as a solving means when not confusing), many kinds of electron-donating dye precursors are mentioned. And various types of reversible developers can be applied, and the thermal conditions for coloring and decoloring differ depending on the combination. In carrying out the present invention, it is also possible to develop a multicolor image by using a plurality of types of reversible recording agents that develop different color tones. In this case, if a plurality of reversible thermosensitive recording layers in the form of spots are composed of a plurality of kinds of reversible recording agents, it is possible to form a multicolor image similar to the multicolor image in a color television.

The surface roughness and the surface hardness are closely related to each other so that the reversible thermosensitive recording layer does not show a trace after being decolored when seen by a person having normal eyesight. Since the protective layer 3 is provided in the present embodiment, it is important to control the surface texture of the protective layer 3. In the present embodiment, a stainless steel ball having a diameter of 0.5 mm is pressed and a load of 300 g is applied. Has a diameter of 0.1 mm or less and a surface roughness Rz of 0.5 to
The thickness was adjusted to 5 μm. Details of these control methods are as described above in the section of the solution.
The details of the method for forming the reversible thermosensitive recording layer 2 on the base film 1 which is a support, and the method for forming the protective layer 3 so as to cover the reversible thermosensitive recording layer 2 are also described above. It is as described in the section of the solution.

The whiteboard sheet 8 constructed as described above is placed on the backboard 16 made of an iron plate,
It is surrounded by a frame 4. The backboard 16 not only mechanically supports the whiteboard sheet 8 and bears the writing pressure, but in the present embodiment, it also participates in the thermal conditions of the color developing and erasing reactions as described below. . The role of the backboard 16 for the color development and decolorization reaction will be described in detail after the hot pen and the eraser are described. The hot pen 4 shown in FIG. 1B is provided with an electric heater 4c while fixing a metal heat rod 4b by projecting it at the tip of a cylindrical heat insulating case 4a made of a heat insulating material. The heat rod 4b can be heated. As a means for supplying power to the electric heater 4c,
Power supply (not shown) having a control function via the cord 4f
May be connected to the charging terminal contact piece 4e for charging
You may provide the battery 4d provided with. As described above, when a multicolor whiteboard sheet is used by using a plurality of types of reversible thermosensitive recording agents, a thermostat (controllable to switch to a temperature suitable for developing each reversible thermosensitive recording agent). (Not shown), or a plurality of hot pens adjusted to have various temperatures are provided.

In the eraser 5 shown in FIG. 1C, a heat plate 5b is attached to a handle 5a made of a heat insulating material, and an electric heater 5c and its power feeding means (cord 5f or terminal contact piece 5e and battery 5).
d) is provided. Further, the eraser 6 shown in FIG. 1 (D) rotatably supports the heat roller 6b having the electric heater 6c by the handle 6a, and the power supply means (the cord 6f or the terminal contact piece 6e and the battery 6d). It is provided. The tip of the heat rod 4b of the hot pen 4 is formed in a convex spherical shape. When the heat rod 4b is heated and slid on the whiteboard sheet 8 as shown by the curved arrow e, the reversible thermosensitive recording layer 2 is heated and rapidly cooled along the curved line to develop color. The mechanism is considered in detail as follows. Considering the point f on the curve, the heating pen heats up and heats up in an instant as it passes, but is cooled after passing. At this time, almost the entire area around the point f is not heated and is at room temperature. Therefore, the amount of heat at the heated point f is absorbed from the surroundings and the temperature is rapidly lowered, so that color is developed. in this case,
Since the backboard 16 having a large heat capacity is present on the back side of the point f, it absorbs heat more quickly and is rapidly cooled to surely develop the color. In this way, the backboard 16 having a large heat capacity promotes the color development reaction of the reversible thermosensitive recording layer 2. Next, when the area g including the point f is heated by the eraser 5 or the eraser 6 as shown by the imaginary line, the entire area around the point f is heated after the eraser is separated. , It does not absorb heat from the surroundings like when a hot pen passes through, and is gradually cooled to erase the color. In this case, if the backboard 16 having a large heat capacity is in contact with the back surface of the whiteboard sheet 8, this backboard 16
After the heat is stored, it fulfills the heat radiation function and promotes the gradual cooling of the point f.
In this manner, the existence of the backboard 16 having a larger heat capacity per unit area than the whiteboard sheet ensures the decoloring operation.

As described above, when a color is drawn by drawing with the hot pen 4, the friction coefficient between the hot pen and the whiteboard sheet affects not only the writing quality but also the coloring state. The reason is that if it slides too much, the heating required for color development is not performed. For this reason, in the present embodiment, the coefficient of friction between the protective layer 3 and the heat rod 4b of the heat pen is adjusted as described above in the section of the solving means. Further, it is necessary that the thickness dimension of the protective layer is appropriate. If the thickness is too large, the heat conduction from the hot pen to the reversible thermosensitive recording layer 2 is hindered and the sensitivity of the color reaction is reduced, but if the thickness is too small, the reversible thermosensitive recording layer 2 is repeatedly used. This is because the effect of increasing the usable number of times is not sufficiently fulfilled. This thickness dimension varies depending on the material of the protective layer, but is preferably 0.5 to 5 g / m ² .

FIG. 2 is a schematic front view showing the appearance of one embodiment of an electronic blackboard type whiteboard constructed by using the whiteboard sheet in the principle diagram shown in FIG. 1 above. Reference numeral 7 is a frame that also serves as an outer casing, and an opening 7a is provided on the front surface thereof. A whiteboard sheet 8 is stretched in a plane so as to cover the opening 7a from the inside. The frame 7 can be supported almost vertically by providing a suspension ring 9 or attaching legs 10. 11 is an instrument table,
The hot pen 4 and the eraser 5 (or 6) described above are held and used.

FIG. 3 is a schematic plan view of the electronic blackboard type whiteboard shown in FIG. 2 mentioned above, cut and cut along the EE plane. However, since it is schematic, it is not necessarily a realistic projection figure. The whiteboard sheet 8 is formed in an endless annular shape and is wound around a pair of rollers 14 and 15. Means (not shown) for rotating and driving the pair of rollers 14 and 15 in the direction of the arrow is provided, and the whiteboard sheet 8 is rotated as indicated by arrows a, b, and c. Looking at the portion where the whiteboard 8 is stretched over the front opening 7a of the frame (see FIG. 2), the whiteboard 8 is fed in the left-right direction as indicated by the arrow a.

When the whiteboard sheet 8 is pressed against the backboard 16 and moved by the hot pen 4 shown in FIG. 3, the image information is shown by handwriting as described above with reference to FIG. You can The whiteboard sheet 8 is provided with a lamp 18 and a reflecting mirror for illuminating an elongated area j in the vertical direction, and an elongated line image in the vertical direction (the direction perpendicular to the paper surface in this figure) facing the area j. A sensor 20 is provided, and a projection lens system 19 for forming an image of the image information shown in the area j on the line image sensor 20 is provided. Board operation panel 12 shown in FIG.
While rotating the whiteboard sheet 8 by operating
By operating the copy operation panel 13, the lamp 18 shown in FIG.
Is turned on and an electric signal is taken out from the line image sensor 20. The extracted electrical signal can be input to a printer (not shown) to hold the image information semipermanently, and the extracted electrical signal can be transmitted and imaged by a CRT or liquid crystal panel for observation at a remote location. Is.

A main heater 17 elongated in the vertical direction is provided on the downstream side of the section j with respect to the feed direction arrows a, b, and c shown in FIG. 3 so as to face the whiteboard sheet 8. A heat retaining plate 17 'is provided on the downstream side of the main heater 17. When the main heater 17 is energized, the temperature is raised to a temperature at which the reversible thermosensitive recording layer can cause a decoloring reaction. The heat retaining plate 17 'is the main heater 17
The heat is transferred from the heat source to raise the temperature within a temperature range insufficient for causing the decoloring reaction. Whiteboard sheet 8 above
When the main heater 17 is energized while rotating, the whiteboard sheet 8 is raised in temperature by the main heater 17 while passing in the direction of the arrow c, and after passing, the whiteboard sheet 8 is allowed to cool and the color developing body disappears. The heat retaining plate 1 as in this embodiment
When 7'is provided, the whiteboard sheet sent in the direction of arrow c is prevented from being rapidly cooled by the heat retaining plate 17 ', and the decoloring action is surely performed. This heat retaining plate 1
The effect of 7'is significant when the rotation speed of the whiteboard sheet 8 is increased.

The heat rods are arranged in the vertical direction (the direction perpendicular to the paper surface in FIG. 3) by being positioned upstream of the line image sensor 20 and downstream of the main heater 17 and the heat retaining plate 17 '. Dot printer 2 with different structure
When 1 is provided, an electric signal can be given to cause the image information to be colored and displayed. It is also possible to remotely operate the dot printer 21.

[0060]

The present invention will be described in more detail with reference to the following examples. Example 1 (A) Preparation of reversible heat-sensitive coating liquid 40 parts of dye precursor 3-di-n-butylamino-6-methyl-7-anilinofluorane together with 90 parts of 2.5% aqueous polyvinyl alcohol solution. It was crushed for 24 hours with a ball mill to obtain a dye precursor dispersion liquid. In contrast, N- [3-
(P-Hydroxyphenyl) propiono] -N'-n-
100 parts of octadecanohydrazide was pulverized with 400 parts of a 2.5% aqueous solution of polyvinyl alcohol in a ball mill for 24 hours to obtain a dispersion liquid. After mixing the above two dispersions,
200 parts of 10% polyvinyl alcohol aqueous solution, 400 water
Parts were added and mixed well to prepare a reversible heat-sensitive coating liquid A.

(B) Coating of reversible thermosensitive recording layer The reversible thermosensitive coating solution A prepared in (A) was applied to a polyethylene terephthalate (PET) sheet support (a) (Toray Lumirror E22, thickness 188 μm, specific gravity 1). .4), a solid content of 4 g / m ² was smeared, dried and then treated with a super calendar to obtain a coated sheet B. (C) Coating of intermediate layer On the coating layer of the coating sheet B obtained in (B), a coating solution consisting of polyvinyl alcohol alone is applied and dried so that the coating amount of solid content is 1 g / m ^2, and the intermediate layer Was provided to obtain a coated sheet C. (D) Coating of protective layer On the coating layer of the coating sheet C obtained in (C), Aronix M
8030 (manufactured by Toagosei Chemical Industry Co., Ltd.) 85 parts, N-vinyl-
2-Pyrrolidone (5 parts), Irgacure 500 (manufactured by Ciba-Geigy Japan), 5 parts, Mizukasil P-527 (manufactured by Mizusawa Chemical Co., Ltd.) were added and sufficiently stirred to apply an ultraviolet-curable resin composition at 1.5 g / m ^2. After that, curing was carried out by an ultraviolet irradiation device (Rapid Cure, manufactured by Ushio Inc.) to obtain a reversible thermosensitive recording material having a protective layer.

Example 2 Polyethylene terephthalate (PET) sheet support (a) used in (B) of Example 1 (Lumirror E2 manufactured by Toray Industries, Inc.)
2, thickness 188 μm, specific gravity 1.4) was changed to Example 1 except that polyethylene terephthalate (PET) sheet support (b) (ICIN Melinex E339, thickness 97 μm, specific gravity 1.4) was changed. A reversible thermosensitive recording material was obtained.

Comparative Example 1 Polyethylene terephthalate (PET) sheet support (a) used in (B) of Example 1 (Lumirror E2 manufactured by Toray Industries, Inc.)
2, thickness 188 μm, specific gravity 1.4) polyethylene terephthalate (PET) sheet support (C) (Toray E2
2. A reversible thermosensitive recording material was obtained in the same manner as in Example 1, except that the thickness was changed to 75 μm and the specific gravity was changed to 1.4). Comparative Example 2 Polyethylene terephthalate (PET) sheet support (a) used in (B) of Example 1 (Lumirror E2 manufactured by Toray Industries, Inc.)
2, thickness 188 μm, specific gravity 1.4) polyethylene terephthalate (PET) sheet support (d) (Toray E6
2, except that the thickness was 188 μm and the specific gravity was 1.0)
A reversible thermosensitive recording material was obtained in the same manner as in Example 1. Comparative Example 3 Polyethylene terephthalate (PET) sheet support (a) used in (B) of Example 1 (Lumirror E2 manufactured by Toray Industries, Inc.)
2, thickness 188 μm, specific gravity 1.4) was changed to Example 1 except that polyethylene terephthalate (PET) sheet support (e) (Toyobo Crisper G2323, thickness 100 μm, specific gravity 1.1) was changed. A reversible thermosensitive recording material was obtained.

Comparative Example 4 (D) The protective layer of Example 1 was changed as follows, except that
A reversible thermosensitive recording material was obtained in the same manner as in Example 1. (D) Coating of protective layer On the coating layer of the coating sheet C obtained in (C), Aronix M
8030 (manufactured by Toagosei Chemical Industry Co., Ltd.) 85 parts, N-vinyl-
After adding 5 parts of 2-pyrrolidone and 5 parts of Irgacure 500 (manufactured by Nippon Ciba-Geigy) and sufficiently stirring, a UV-curable resin composition was applied at 1.5 g / m ^2, and then an ultraviolet irradiation device (Ushio Denki, Rapid) Curing was performed to obtain a reversible thermosensitive recording material having a protective layer.

Comparative Example 5 (D) The protective layer of Example 1 was changed as follows, except that
A reversible thermosensitive recording material was obtained in the same manner as in Example 1. (D) Coating of protective layer On the coating layer of the coating sheet C obtained in (C), Aronix M
8030 (manufactured by Toagosei Chemical Industry Co., Ltd.) 85 parts, N-vinyl-
After adding 5 parts of 2-pyrrolidone, 5 parts of Irgacure 500 (manufactured by Ciba-Geigy) and 5 parts of Sylysia 470 (manufactured by Fuji Silysia Chemical Ltd.), the mixture was sufficiently stirred and applied to give an ultraviolet curable resin composition of 1.5 g / m ^2. Then, curing was performed with an ultraviolet irradiation device (Rapid Cure, manufactured by Ushio Inc.) to obtain a reversible thermosensitive recording material having a protective layer.

Test 1 (deformation by pressing) A stainless steel ball having a diameter of 0.5 mm was applied to the surfaces of the reversible thermosensitive recording materials obtained in Examples 1 and 2 and Comparative Examples 1 to 5 while applying a load of 300 g. The stainless steel ball was moved to a 3 cm straight line. Then, the reversible thermosensitive recording material was cut perpendicularly to the surface, and the deformation due to pressing was measured with a microscope. The results are shown in Table 1. Test 2 (Measurement of Surface Roughness Rz) The surface of the reversible thermosensitive recording materials obtained in Examples 1 and 2 and Comparative Examples 1 to 5 was measured with a surface roughness meter (Surfcom manufactured by Tokyo Seimitsu Co., Ltd.).
5. IS B 0601 The ten-point average roughness Rz was measured according to. The results are shown in Table 1. Test 3 (image formation / erasing) A straight line was drawn on the reversible thermosensitive recording materials obtained in Examples 1 and 2 and Comparative Examples 1 to 5 with a hot pen (surface temperature of contacting portion: 140 ° C), and then heat block (contacting). Surface temperature of part 120 ℃)
It was erased with and the trace of color development was observed. The results are shown in Tables 1 and 2.

[0067]

[Table 1]

[0068]

[Table 2]

The reversible thermosensitive recording materials obtained in Examples 1 and 2 did not show any coloration traces even after the operation of erasing with a heat block following coloration with a hot pen. On the contrary,
In Comparative Examples 1 to 5, when the operation of erasing by the heat block subsequent to the color development by the hot pen is performed, the color development trace is seen. Further, in Comparative Examples 4 to 5, although there is no deformation due to pressing,
A color trace was seen. From this, it was confirmed that due to the combined effect of the degree of deformation due to pressing and the degree of surface roughness of the present invention, the color-developed trace cannot be visually recognized. From this, a clear difference is observed between the example and the comparative example, and it is confirmed that the present invention has a great effect.

[0070]

INDUSTRIAL APPLICABILITY The reversible thermosensitive recording material in the series of inventions according to the present application has a surface roughness Rz of 0.5 to 5 μm, and the surface of the reversible thermosensitive recording material is 0 to 5 μm. 30 stainless steel balls with a diameter of 0.5 mm
When the pressure is applied with a load of 0 g, the reversible thermosensitive recording material has a deformation of not exceeding 0.1 mm,
The contact portion between the heating element and the surface of the reversible thermosensitive recording material is 0.
When a hot pen having a diameter of 5 mm or more is used, the support or the coating layer is not deformed, and the color trace is not visually recognized when the color is developed by the hot pen and erased by the heating block.

According to the heat-sensitive coloring / heat-erasing type whiteboard (Claim 1) according to the present invention, the reversible heat-sensitive recording layer does not change its transparency depending on the temperature conditions as in the conventional example. Since the image is erased or erased, not only dust is not generated during the erasing, but also the contrast of the image information shown by the coloring is sufficient and the outline is clear. Moreover, since the hardness of the reversible thermosensitive recording layer is properly set in relation to the writing pressure of the hot pen, the indentation left after the color is erased is not visually recognized, and the number of times of repeated use is large.

In carrying out the whiteboard of the present invention, if a backboard having a large heat capacity is provided on the back surface of the whiteboard sheet (claim 2), the reversible thermosensitive recording layer absorbs heat from the portion heated by the hot pen. Color development can be promoted, and heat of the portion heated by the erasing member can be stored to promote decolorization. When carrying out the whiteboard of the present invention, when the whiteboard sheet is formed into an endless ring and is wound around two vertical rollers and rotated (claim 3),
Colored image information can be temporarily stored and stored, or it can be taken out again and posted, and in addition, the image information different from the above is displayed in the margin of the whiteboard sheet during the above storage and storage. It can also be shown.

When the whiteboard of the present invention is carried out, the whiteboard sheet is formed in an endless ring shape so that the whiteboard sheet can be wound around two rollers to be fed and operated, and the illumination means, the line image sensor, and the projection lens can be used. When the system is provided (Claim 4), the image information on the whiteboard can be detected as an electric signal, so that the printing means can be operated and the detection signal can be transmitted to a remote place. . When the whiteboard of the present invention is carried out, the whiteboard sheet is configured as an endless ring so that the whiteboard sheet can be wound around two rollers to be fed and operated, and a heater for erasing can be provided by facing the whiteboard sheet. If provided (Claim 5), the image information showing the color development can be erased automatically or semi-automatically.

When carrying out the whiteboard of the present invention, the whiteboard sheet is formed into an endless ring shape and 2
A desired type of image information can be automatically or semi-automatically colored by wrapping around a book roller so that it can be fed, and by providing a heat type dot printer facing the whiteboard sheet (Claim 6). be able to.

When the whiteboard of the present invention is implemented, by using a heat rod (heat pen) provided with an electric heater and a power feeding means (claim 7), the operation of displaying the image information by handwriting the color is facilitated. It can be performed reliably. When the whiteboard of the present invention is put into practice, an eraser comprising a heat plate provided with an electric heater, a power feeding means and a handle is used (claim 8), whereby a manual erasing operation can be carried out quickly and easily.
When the whiteboard of the present invention is put into practice, an eraser composed of an electric heater, a power feeding means, and a heat roller provided with a handle is used (claim 9), and a manual decoloring operation can be easily performed with a light force.

When the whiteboard of the present invention is carried out, a plurality of types of reversible recording agents which develop different color tones under different temperature conditions are used, and a plurality of reversible recording agents adapted to the temperature conditions for developing each reversible recording agent are used. If an electric heating pen is provided, it is possible to display multi-colored images and display abundant image information. When carrying out the whiteboard of the present invention, while using a plurality of types of reversible recording agents that develop different color tones under different temperature conditions,
If the temperature of one electric heating pen can be adjusted according to the color development temperature condition of each reversible recording agent, multicolor display can be performed with one electric heating pen.

When the whiteboard of the present invention is carried out, a protective layer is formed on the surface of the reversible thermosensitive recording layer (claim 10) to prevent deterioration of the reversible thermosensitive recording layer due to repeated use. When the hardness is controlled by adding a curing agent to the protective layer (claim 11), the function of making the decolored traces inconspicuous can be surely exhibited. When a pigment is added to the protective layer to control the surface roughness (Claim 12), traces after erasing are made inconspicuous, the gloss of the marking surface is moderated, and writing comfort with a hot pen is adjusted. can do. The writing comfort can be adjusted more precisely by adding a lubricant to the protective layer (claim 13). When the protective layer is formed by sticking a transparent film on the surface of the reversible thermosensitive recording layer (claim 14), a thermosensitive coloring / thermoerasable whiteboard can be industrially produced at low cost. . The thickness of the protective layer is 0.5 to 5 g / m.
^When set to ² (claim 15), the number of times the reversible thermosensitive recording layer can be repeatedly used can be increased without unnecessarily hindering the sensitivity of the thermosensitive reaction.

According to the method for developing and erasing the heat-sensitive color-developing / thermo-erasing type whiteboard according to the present invention (claim 16), it is not a change in the transparency as in the conventional example, but a phenomenon such as color-developing / erasing which is easily visible. You can repeat the operation of showing and erasing image information by using
No dust is generated during erasing and no traces are noticeable after erasing. In addition, the boundary between the colored portion and the non-colored portion is clear, and sufficient contrast can be obtained.

When the coloring and decoloring method of the present invention is carried out, if a pigment is added to the reversible recording agent to control the surface roughness, the gloss of the image information can be moderated to make it easier to visually recognize. When carrying out the coloring and erasing method of the present invention, the whiteboard sheet is formed into an endless annular shape, and when the endless annular whiteboard sheet is fed and operated (Claim 17), color development is performed to display the image information. Can be temporarily stored and stored, and can be quickly and easily taken out as needed. When an eraser is provided so as to face the endless annular whiteboard sheet (claim 18), it is possible to automatically erase the image information of which color development is shown. Further, when a line image sensor and a projection lens system are provided so as to face the endless annular whiteboard sheet (claim 19), the image information represented by color development is converted into an electric signal to semipermanently. Can be recorded and sent. Further, when a heat rod type dot printer is provided so as to face the whiteboard sheet (claim 20), electric signals can be converted into image information. When carrying out the coloring and erasing method of the present invention,
Multi-color image information can be displayed by using a plurality of types of reversible recording agents having different color tones and color development temperature conditions and using a hot pen which gives each color development temperature condition.

[Brief description of drawings]

FIG. 1 is shown for explaining the principle of the basic structural function of the present invention, (A) is a perspective view of a whiteboard main body partly broken and drawn, and (B) is a hot pen. Is an external perspective view of an eraser, and (D) is an external perspective view of an eraser different from the above.

FIG. 2 is a front view schematically showing the external appearance of one embodiment of an electronic blackboard type whiteboard configured by using the whiteboard sheet in the principle diagram shown in FIG. 1 above.

FIG. 3 is a schematic plan view of the electronic blackboard type whiteboard shown in FIG. 2 described above cut along the EE plane. However, since it is schematic, it is not necessarily a realistic projection figure.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Base film, 2 ... Reversible thermosensitive recording layer, 3 ... Backboard, 4 ... Thermal pen 4a ... Insulating case, 4b ... Heat rod, 4c ... Electric heater, 4d ... Battery, 4e ...
Terminal contact piece, 4f ... Cord, 5 ... Eraser, 5a ... Insulating handle, 5b ... Heat plate, 5c ... Electric heater, 5d ... Battery, 5e ... Terminal contact piece, 5f ... Cord,
6 ... Eraser, 6a ... Insulating handle, 6b ... Heat roller, 6c ... Electric heater, 6d ... Battery, 6e ... Terminal contact piece, 6f ... Cord, 7 ... Frame, 7a ... Front opening, 8 ... Whiteboard sheet, 9 … Suspension rings, 10… Legs,
11 ... Instrument table, 12 ... Board operation panel, 13 ... Copy operation panel, 14, 15 ... Roller, 16 ... Backboard,
17 ... Main heater, 17 '... Heat retaining plate, 18 ... Lamp, 19
... Projection lens system, 20 ... Line image sensor, 21 ...
Dot printer.

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Yukio Tahara 3-4-2 Marunouchi, Chiyoda-ku, Tokyo Sanryo Paper Co., Ltd. (72) Hidemi Hanada 3-4-2, Marunouchi, Chiyoda-ku, Tokyo 3 Ryo Paper Co., Ltd.

Claims (20)

[Claims] 1. A surface of a base film, which is a support,
A reversible recording agent containing a "usually colorless to light-colored electron-donating dye precursor" and "a reversible developer that causes the dye precursor to develop color by heating / cooling and decolorizes the color former by reheating / cooling" A whiteboard sheet having a reversible thermosensitive recording layer formed thereon, and a high-temperature convex curved surface that is brought into point contact with the reversible thermosensitive recording layer, and the reversible thermosensitive recording layer is locally formed by the contact of the convex curved surface. And a high-temperature flat surface or a high-temperature cylindrical surface that is brought into surface contact or line contact with the reversible thermosensitive recording layer, and the reversible contact is caused by the contact of the flat surface or the cylindrical surface. And a member for erasing that heats a specific area of the thermosensitive recording layer to erase the color, and the surface roughness Rz of the reversible thermosensitive recording layer is 0.5 to
The surface of the reversible thermosensitive recording layer has a diameter of 5 μm, and a stainless steel ball having a diameter of 0.5 mm is brought into contact with the surface of the reversible thermosensitive recording layer.
A heat-sensitive color-developing / heat-erasing whiteboard characterized in that the diameter dimension of the indentation caused by plastic deformation of the surface does not exceed 0.1 mm when a load of 00 g is applied. 2. A backboard having a heat capacity per unit area larger than that of the whiteboard sheet is provided by contacting the backside of a whiteboard sheet having a reversible thermosensitive recording layer formed on the surface of the base film. And
After the pressing force of the description member is supported, and the reversible thermosensitive recording layer is locally heated to end the heating, the amount of heat of the reversible thermosensitive recording layer that has risen is absorbed by the backboard and rapidly. After being cooled, the coloring effect is promoted, and when the characteristic range of the reversible thermosensitive recording layer is heated, a part of the heat amount is stored in the backboard, and after the above heating is finished. The thermosensitive coloring / thermosensing according to claim 1, wherein the reversible thermosensitive recording layer, which has been heated, is gradually cooled by heat retention of the backboard to promote decoloring action. Decolorable whiteboard. 3. The whiteboard sheet has an endless annular shape, and vertical rollers are arranged at both left and right ends of a board frame, and the endless annular whiteboard sheet is wound around the rollers. The backboard is disposed so as to cover the front opening of the frame from the inside, and means for rotating the roller is provided, and with the rotation of the roller, The heat-sensitive coloring / heat-erasing type according to claim 2, wherein the whiteboard sheet wound around the backboard is fed in the left-right direction while sliding on the front surface of the backboard. Whiteboard. 4. A means for illuminating the whiteboard sheet so as to face the whiteboard sheet, a line image sensor installed substantially vertically, and shape information on the whiteboard sheet, The heat-sensitive color-developing / heat-decoloring whiteboard according to claim 3, further comprising a lens system for forming an image on the image sensor. 5. The whiteboard sheet wound around the roller is heated so that the whiteboard sheet faces a long and narrow area of the endless annular shape substantially perpendicular to the longitudinal direction.
5. A heater for cooling and performing a color erasing action is provided.
A heat-sensitive coloring and heat-erasing whiteboard described in. 6. A direction substantially perpendicular to the longitudinal direction of the endless annular shape of the whiteboard sheet wound around the roller,
4. A dot printer comprising a large number of rods having a high temperature convex curved surface is installed so as to face the surface of the whiteboard sheet in parallel.
A thermosensitive coloring / erasing whiteboard according to any one of claims 1 to 5. 7. The description member, wherein the heat rod is made of a heat conductive material having a convex curved surface at the tip, an electric heater for heating the heat rod, a means for supplying electric power to the electric heater, and a heat insulator. A heat-sensitive coloring / heat-erasing whiteboard according to claim 1 or 2, further comprising an elongated case made of a conductive material. 8. The erasing member is made of a heat conductive material having a flat surface, a heat plate, an electric heater for heating the heat plate, a means for supplying electric power to the electric heater, and a heat insulating material. A heat-sensitive coloring / heat-erasing whiteboard according to claim 1, 2 or 7, further comprising a handle. 9. The erasing member comprises a heat roller made of a heat conductive material having a cylindrical surface, an electric heater for heating the heat roller, a means for supplying electric power to the electric heater, and the heat roller. The heat-sensitive coloring and heat-erasing whiteboard according to claim 1, 2 or 7, further comprising a handle made of a heat insulating material rotatably supported. 10. The surface of the reversible thermosensitive recording layer is covered with a protective layer formed by layering and curing a protective agent in a fluid state, and the reversible thermosensitive recording layer is repeatedly subjected to thermosensitive coloring / decoloring. The heat-sensitive coloring / heat-erasable whiteboard according to any one of claims 1 to 9, wherein deterioration due to the protection layer is prevented by the protective layer. 11. A curing agent is added to the protective agent, and the state of occurrence of indentation when a load is applied to the surface of the protective layer by the stainless steel balls by adjusting the type and the addition amount of the curing agent. The heat-sensitive color development according to claim 10, wherein the color is adjusted to 0.1 mm or less.
A heat-erasable whiteboard. 12. A pigment is added to the protective agent, and the surface roughness Rz of the protective layer is adjusted to 0.5 to 5 μm by adjusting the type and the addition amount of the pigment. The thermosensitive coloring / erasing whiteboard according to claim 10 or 11. 13. A lubricant is added to the protective agent, and the coefficient of friction of the protective layer with respect to the descriptive member is adjusted by adjusting the type and amount of the lubricant. A heat-sensitive color-developing / heat-erasing color whiteboard according to any one of claims 10 to 12. 14. The surface of the reversible thermosensitive recording layer is covered with a protective layer formed by adhering a film-like member transparent to visible light, which is formed separately from the surface of the reversible thermosensitive recording layer. The heat-sensitive coloring / heat-erasing whiteboard according to any one of claims 1 to 9. 15. The thickness dimension of the protective layer is 0.5 to 5 g / m ² in terms of weight per unit area, and any one of claims 10 to 14 is characterized. A heat-sensitive coloring and heat-erasing whiteboard as described in (1). 16. A "usually colorless or light-colored electron-donating dye precursor" and "a reversible developer that causes the dye precursor to develop color by heating / quenching and decolorizes the color developing body by reheating / slow cooling". By constituting a reversible recording agent, forming a reversible thermosensitive recording layer by layering the reversible recording agent on a base film, and heating and quenching by contacting the reversible thermosensitive recording layer with a heating pen. A thermosensitive coloring / thermosensitive decoloring method characterized in that the reversible thermosensitive recording layer is heated and gradually cooled to erase the color by contacting a member having a high temperature surface with the above-mentioned colored portion. How to emit and erase the whiteboard. 17. A whiteboard sheet composed of a base film in which the reversible recording layer and the protective layer are laminated is formed in an endless ring shape, and a pair of rollers are arranged substantially vertically and separated from each other, and A means for rotationally driving at least one of the pair of rollers is provided, the endless annular whiteboard sheet is wound around the pair of rollers, and the whiteboard sheet is rotated by rotating the roller. The method for producing and erasing a heat-sensitive coloring / erasing type whiteboard according to claim 16, wherein the portion facing the board is moved to the left and right. 18. An eraser comprising a heater having an elongated shape is disposed in the width direction of the whiteboard sheet so as to face the endless annular whiteboard sheet wound around the pair of rollers and rotated. By rotating the whiteboard sheet,
18. The method for producing and erasing a heat-sensitive coloring / erasing whiteboard according to claim 17, wherein the eraser relatively wipes the surface of the whiteboard sheet to perform an erasing action. 19. An illuminating means and a line image are arranged such that an arbitrary portion on a whiteboard sheet to be rotated is opposed to and spaced apart from the backboard downstream of the backboard and upstream of the eraser with respect to a moving path thereof. A sensor, and a lens system for forming image information on the whiteboard sheet, which is formed on the whiteboard sheet, is formed on the line image sensor, and the image is permanently stored before being erased, or The method for emitting and erasing a thermosensitive coloring / erasing whiteboard according to claim 18, characterized in that the information is transmitted to a remote place. 20. A dot printer provided with a large number of rods having a heated spherical surface facing the upstream side of the backboard and the downstream side of the eraser with respect to the moving path of the whiteboard sheet. 20. The whiteboard sheet is disposed, and while rotating the whiteboard sheet, a specific rod among the plurality of rods is selectively brought into contact with the whiteboard sheet to develop a color. How to develop and erase heat sensitive coloring and heat erasing type whiteboard.