JP2002160454A - Reversible heat-sensitive recording medium - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a reversible heat-sensitive recording medium not liable to leave unerased parts even by a repeated use. SOLUTION: The reversible heat-sensitive recording medium comprises a reversible heat-sensitive recording layer containing a reversible heat-sensitive composition capable of forming a state in which an electron donative colorant compound and an electron acceptive compound relatively color develop due to a difference of heating temperatures and/or cooling speeds after heating on a support, and a protective layer provided on the recording layer. A dynamic frictional coefficient of the surface of the protective layer is 0.2 or less. A surface glossiness is 40% or less. A peak temperature of a viscoelasticity logarithmic decrement measured by a rigid pendulum automatic attenuation vibrating method is 100 deg.C or higher. The logarithmic decrement at the peak temperature is 0.3 or less.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a reversible thermosensitive coloring composition utilizing a coloring reaction between an electron-donating color-forming compound and an electron-accepting compound. The present invention relates to a reversible thermosensitive recording medium capable of forming and erasing.

[0002]

2. Description of the Related Art Conventionally, an electron-donating color-forming compound (hereinafter, referred to as an electron donating color compound)
Thermal recording media utilizing a color development reaction between a color former or a leuco dye) and an electron-accepting compound (hereinafter also referred to as a developer) are widely known, and with the progress of OA, facsimile, word processor, It is widely used as output paper for scientific measuring instruments and more recently as magnetic thermal cards such as prepaid cards and point cards. However, these conventional recording media that have been put into practical use have been reviewed due to environmental issues, such as recycling and reducing the amount of usage. However, since the color is irreversible, once recorded images have been erased, It cannot be used repeatedly, and the area of the recordable part is limited as new information is added to the part where no image is recorded. Therefore, the actual situation is that the amount of information to be recorded is reduced or the card is recreated when the recording area runs out. Therefore, development of a reversible thermosensitive recording medium that can be rewritten any number of times has been desired in the background of the problems of garbage and deforestation that have been actively discussed in recent years.

[0003] From these requirements, various reversible thermosensitive recording media have been proposed. For example, a polymer type reversible thermosensitive recording medium utilizing physical changes such as transparency and opacity is disclosed in JP-A-63-107584 and JP-A-4-78.
No. 573, for example. Also, a dye type reversible thermosensitive recording medium utilizing a chemical change has been proposed. Specifically, JP-A-60-1 using a combination of gallic acid and phloroglucinol as a color developer
No. 93691, JP-A-61-2 using a compound such as phenolphthalein or thymolphthalein as a developer.
No. 37684, JP-A-62-138, in which a recording layer contains a homogeneous solution of a color former, a developer and a carboxylic acid ester.
556, JP-A-62-138568 and JP-A-62-140881, JP-A-63-173684 using an ascorbic acid derivative as a color developer,
JP-A-2-188 using a salt of bis (hydroxyphenyl) acetic acid or gallic acid with a higher aliphatic amine as a developer
293 and JP-A-2-188294 are disclosed.

Further, the present inventors have disclosed in Japanese Patent Laid-Open No.
No. 4360, an organic phosphoric acid compound, an aliphatic carboxylic acid compound or a phenol compound having a long-chain aliphatic hydrocarbon group is used as a color developer, and color development and quenching are performed by combining this with a leuco dye as a color former. Color can be easily controlled by heating and cooling conditions, and its color-developed state and decolored state can be stably maintained at room temperature, and reversible thermosensitive color development that can repeat color development and decoloration A composition and a reversible thermosensitive recording medium using the same in a recording layer were proposed. Thereafter, use of a specific structure for a phenol compound having a long-chain aliphatic hydrocarbon group has been proposed (Japanese Patent Application Laid-Open No. 6-210954).

As described above, various reversible thermosensitive recording media capable of repeating coloring and erasing have been proposed. However, if printing and erasing are repeatedly performed under practical conditions, the image density may decrease or be reduced. Problems such as scars, flaws, and unerasable parts have occurred, and a reversible thermosensitive recording medium which can sufficiently exhibit the color developing and decoloring properties of the developer and leuco dye composition has not been obtained. This is because printing by the thermal head is performed while applying mechanical force to the recording medium at the same time as high-temperature heating, so that the structure of the layers constituting the recording medium, such as the recording layer and the protective layer, changes and is repeatedly destroyed. That is because

In order to solve such a problem of the recording medium, Japanese Patent Application Laid-Open No. Hei 6-340171 discloses an improvement in the repetition durability by adding particles having an average particle diameter of 1.1 times or more the thickness of the recording layer. Japanese Patent Application Laid-Open No. Hei 8-156410 proposes that a protective layer having a specific glossiness and surface roughness is provided to improve the head matching property and maintain the decoloring property. Further, Japanese Patent Application Laid-Open No. 10-2645
In JP-A-21, durability is improved by including a pigment surface-treated with a silane coupling agent, a titanate coupling agent or an aluminum coupling agent. However, even if such a recording layer and a protective layer are used, damage is increased by repeated printing and erasing, and unerased portions are generated. For this reason, there is a problem that the number of times of repeated use is substantially limited to a small number.

[0007]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a reversible thermosensitive recording medium in which an unerased portion hardly occurs even after repeated use.

[0008]

Means for Solving the Problems The present inventors have conducted studies to solve these problems, and as a result, have determined the coefficient of kinetic friction on the surface of the protective layer, the surface glossiness, and the strength of the coating film with a rigid pendulum. As a result, the present inventors have found that a reversible thermosensitive recording medium in which the unerased residue hardly occurs can be obtained, and the present invention has been completed.

That is, a reversible heat-sensitive material which can form a relatively colored state by using an electron-donating color-forming compound and an electron-accepting compound on a support and changing the heating temperature and / or the cooling rate after heating. In a reversible thermosensitive recording layer containing a composition, and a reversible thermosensitive recording medium comprising a protective layer provided on the reversible thermosensitive recording layer, the surface of the protective layer has a dynamic friction coefficient of 0.2 or less, and The glossiness is 40% or less, and the peak temperature of the viscoelastic logarithmic decrement measured by the rigid pendulum automatic damping vibration method is 100 ° C. or more, and the logarithmic decrement at the peak temperature is 0.3 or less, or When the peak temperature of the logarithmic decay rate is 150 ° C. or more and the logarithmic decay rate at the peak temperature is 0.6 or less, a reversible thermosensitive recording medium which is hardly erased even by repeated use and hardly generates residual is obtained. It was found to be. Furthermore,
The protective layer contains silica particles coated or complexed with calcium or a resin in which a silicone segment is bonded in a block or graft form, and the protective layer is in a cross-linked state with an isocyanate-based curing agent, so that the protective layer is further enhanced. It has been found that the occurrence of unerased parts due to repetition can be suppressed.

In the present invention, the material used for the protective layer provided on the reversible thermosensitive recording layer belongs to a polymer material. Generally, the chemical structure of the polymer material depends on the glass transition temperature and the melting point _Tm . A similar effect, empirically, for asymmetric polymers, T _g is approximately ／ of T _m (where T is absolute temperature),
It is known that T _g is approximately の of T _m in _symmetric polymers. The melting point T _{m of the} polymer material is as follows: T _m = (H ₁ −H _c ) / (S ₁ −S _c ) = ΔH _f / ΔS _f (H is enthalpy, S is entropy, and subscripts 1 and c are melting points. Liquid, solid, subscript f at (absolute temperature)
Is a molten state).

[0011] structure that the glass transition point of the polymer, outline of influence on the melting point are those known to very constant, for example, enthalpy change is a parameter of the melting point T _m in the above equation (typically Specifically, for example, the amount of heat generated when the individual groups cohere with each other and the internal heat absorbed in the form of latent heat during heating, ΔH, and the amount of entropy change (typically, There is a correlation between ΔS and the structure of the polymer, for example, ΔH _f is mainly affected by the type of the group located in the side chain, and forms a hydrogen bond. When -CONH-, -NHCOO-, -OH or the like is introduced into a side chain, or when a -CN group having dipole interaction, a halogenated hydrocarbon group, or the like is introduced, a given heat is applied. External d Since energy is first absorbed as latent heat for solving these hydrogen bonds and dipole interactions, it is empirically known that ΔH _f in the above equation increases and T _m increases, while ΔS _f is correlated with the degree of conformational change and molecular weight, such as whether the main chain that mainly governs the primary structure of the polymer is rigid or easy to bend. In the case where a —CH ₂ — structure or —CO—C— structure that imparts the formula ( ₁₎ is present in the main chain, the denominator ΔS _f is large, so that T _m is lowered. It is empirically known that when the diameter of the helical structure (helical structure) is large, the primary structure of the polymer becomes rigid, ΔS _f decreases, and T _m increases. Concepts such as those shown are empirically known and ideal It is considered that the resin for the reverse thermosensitive recording medium is in a very narrow area between the rubber-like or paste-like substance and the fibrous substance.
This can be considered in comparison with the physical properties of the polymer as shown in FIGS.

However, the general concept as shown in FIG. 14 does not always apply to most polymer materials for reversible recording media. In other words, in the case of a reversible thermosensitive recording medium, image coloring properties, image decoloring properties, head matching properties, curling resistance, and the like must be satisfied. Must be satisfied, so that not only ΔS and ΔH,
Consideration must also be given to problems that depend on the molecular weight of the polymer and its distribution (for example, the effect of the terminal group of the mixed small molecular weight polymer and the action of the small molecular weight polymer as a solvent), rheology, surface tension, and the like. However, as can be understood from the graphs of FIGS. 17 and 18, for example, those obtained by curing an aqueous emulsion generally have no peak temperature of the logarithmic decay rate in many cases. In addition, a cured coating film is generally very thick, and the cured state is different between the inside and the surface of the layer, so that a plurality of peak temperatures of the logarithmic decay rate tend to occur.

[0013] The ordinary thermoplastic resin has a peak temperature.
Most (Tg) is less than 100 ℃
Those that are not less than 150 ° C are special. In the present invention, when a crosslinked resin is used, it is necessary to carefully control the degree of crosslinking. Special for those with a peak temperature of 150 ° C or higher (Tg: -125 ° C for polyethylene, -123 ° C for polydimethylsiloxane, -90 ° C for polybutadiene, -73 ° C for isoprene
℃, isobutylene -60 ℃, polyoxymethylene -50
℃, -35 ℃ with polyvinylidene fluoride, with polypropylene-
18 ° C, -17 ° C with polyvinylidene chloride, 3 ° C with polymethyl acrylate, 29 ° C with polyvinyl acetate, 50 with nylon 66
℃, nylon 6 50 ℃, nitrocellulose 53 ℃, high Tg PET 69 ℃, triacetyl cellulose 69 ℃, polyvinyl fluoride 73 ℃, polyvinyl alcohol 85 ℃, polyvinyl chloride 87 ℃ For those at 100 ° C or higher, polystyrene whose main chain segment should be rigid and high Tg due to the high frequency of phenyl groups
104,130 ° C for polyacrylonitrile, which should have a high Tg due to the high frequency of strong polar groups at 100,105 ° C and strong polar groups, and 1 for polymethyl methacrylate
05,120 ℃, 105 ℃ with polyvinyl formal, 126 ℃ with polytetrafluoroethylene, 150 ℃ with polycarbonate
In many cases, those having a higher Tg (Tg of 150 ° C. or higher) belong to the so-called engineering plastics category such as polyaryl resin resins, and include phenyl groups and / or extremely strong polar groups.
(For example, -CN group, -OH group, -CONH- site, etc.) must be present frequently.) On the other hand, according to the rigid pendulum automatic damping vibration method, desirable characteristics of the reversible thermosensitive recording medium can be grasped practically and clearly.

Hereinafter, the reversible thermosensitive recording medium of the present invention will be described in detail. When the heat generating device and the recording medium come into contact with each other, the protective layer needs to have a slippery property so that the two can be transported between the two without resistance. It is conceivable to add a lubricant to this problem, and specifically, it can be solved by using a silicone resin. In addition, in order to provide head matching with the heat-generating device, it is necessary to make the surface of the protective layer uneven so that the surface becomes somewhat rough. Generally, the head matching property can be solved by adding a filler to the protective layer.
Further, the recording medium is repeatedly printed / erased, and each time the recording medium is exposed to a heating device, the recording medium must have heat resistance and mechanical strength. That is, the protective layer needs to be hardly changed by heat and resistant to mechanical stress.
In order to solve this, it is conceivable to use a resin having high heat resistance for the protective layer. In addition, by crosslinking the binder resin with a curing agent, heat resistance and mechanical strength can be further increased. However, even with these general materials and methods, it has been very difficult to eliminate the unerased residue due to repetition.

The inventors of the present invention have conducted intensive studies and have determined that the three characteristic values of the coefficient of kinetic friction of the surface of the protective layer, the surface glossiness, and the strength of the coating film with a rigid pendulum are defined, and thus the durability as well as the durability are improved. It has been found that a reversible thermal recording medium capable of suppressing the occurrence of the unerased residue due to the above can be obtained. It is considered that the unerased residue is caused by the structural change of the substance formed in the recording layer. By giving the above-mentioned characteristic values to the protective layer, the damage applied to the recording layer is greatly reduced, and the structure inside the recording layer is reduced. It is presumed that changes could be prevented and the occurrence of unerased parts could be reduced.

More specifically, the coefficient of kinetic friction of the protective layer according to the present invention is preferably 0.2 or less. If the coefficient of kinetic friction is larger than 0.2, the slipperiness of the surface is reduced, and poor transport is caused. This causes a problem that the erasure remaining increases. Further, the surface glossiness is preferably 40% or less, more preferably 5% or more and 35% or less. If it is larger than 40%, erase marks are conspicuous, and an illusion of an increase in unerased residue occurs.

The logarithmic decay rate measured by the rigid pendulum automatic damping vibration method in the present invention indicates the degree of hardness and flexibility of the coating film. The smaller the value, the denser the crosslinking density and the rigidity of the coating film. Is represented. The peak temperature of the logarithmic decay rate represents the glass transition temperature Tg, and the higher the Tg point, the higher the temperature at which the polymer main chain is rigid and the transition from the glassy state to the rubbery state is higher.
From the above, in order to maintain repeated durability and further reduce the occurrence of erasure residue, if the coating film is soft, the glass transition temperature is high, or if the glass transition temperature is low, the coating film has rigidity. I just need. That is, the peak temperature of the logarithmic decay rate on the reversible thermosensitive recording layer side is 100 ° C. or more, and the logarithmic decay rate at the peak temperature is 0.3 or less, or the peak temperature of the logarithmic decay rate is 150 ° C. or more, and the logarithm at the peak temperature is It is important that the decay rate satisfies the relationship of the viscoelastic property values of 0.6 or less.

Next, by using silica particles coated or composited with calcium for the protective layer of the reversible thermosensitive recording medium of the present invention, the coefficient of kinetic friction is reduced, and unerased portions are less likely to be generated. Further, the average particle diameter of the silica particles is preferably 0.3 to 3.0 μm, and 0.3 μm
If it is less than 1, the filler does not precipitate on the surface, so that the effect of addition cannot be obtained. On the other hand, if it is larger than 3.0 μm, the contact with the heating device will be poor, and the heat transfer will be insufficient, and the unerased residue will increase. Further, the content of the silica particles is preferably 5 to 50 parts by weight based on 100 parts by weight of the protective layer resin in terms of the solid content, and if it is less than 5 parts by weight, it is insufficient to form irregularities on the surface. In addition, the effect of adding a filler cannot be obtained. On the other hand, if it exceeds 50 parts by weight, the contact with the heating / erasing device becomes poor, and the heat transfer becomes insufficient, resulting in a problem that the erasing residue increases.

The logarithmic decay rate in the present invention is measured by the following method. Measuring device: R & D RPT-3000, rigid pendulum type physical property tester manufactured by A & D Corporation

Rigid pendulum: round bar type cylinder edge RB
Combination of P-040 and rigid pendulum FRB-100

Sample: All layers used on the reversible thermosensitive recording layer side or the curl prevention layer side are coated on an arbitrary support so as to have the same thickness. Then, place the sample in width 20
mm and cut into 25 mm length. (In the case of a recording medium that is already a product, the same result can be obtained without any problem even if the front side and the back side are measured.)

Measurement procedure: The sample is placed on a heating / cooling block, and the cylinder edge RBP-040 is placed on the sample measurement surface. Next, the oscillation of the pendulum is started, and the pendulum is heated from 25 ° C. to 200 ° C. at a rate of 9 ° C./min.

Analysis: The free vibration period and the vibration amplitude of the pendulum are analyzed, and the logarithmic decay rate for each measured temperature is obtained and plotted on a logarithmic decay rate curve. The temperature at which the logarithmic decay rate curve shows the maximum value is defined as the peak temperature of the logarithmic decay rate. The logarithmic decay rate at this temperature is defined as the logarithmic decay rate at the peak temperature.

The dynamic friction coefficient in the present invention is measured by the following method. The measurement was performed using a static / dynamic friction coefficient measuring device (manufactured by Kyowa Interface Science Co., Ltd.). The settings at that time were as follows: the surface contact (1 cm ² ), the load was 400 g, the stroke was 30 mm, the moving speed was 0.5 mm / s, and the dynamic friction coefficient was obtained from the average of five times.

In the present invention, the glossiness is measured according to JIS.
It was measured by a specular gloss measurement method at 60 degrees incidence based on the Z8741 method. The measuring device used was a variable-angle gloss meter (VGS-1001DP manufactured by Nippon Denshoku Industries Co., Ltd.).

As the leuco dye used in the present invention, one or more compounds used in this type of reversible thermosensitive recording medium can be used.
Known dye precursors such as a phthalide compound, an azaphthalide compound, and a fluoran compound are exemplified.

Representative examples of the developer used in the present invention include, for example, JP-A-5-12436.
0, JP-A-6-210954 and JP-A-10
-95175 compound. The color developing agent used herein has a structure having a color developing ability to develop a leuco dye in a molecule, for example, a phenolic hydroxyl group, a carboxylic acid group, a phosphoric acid group, and a structure for controlling the cohesive force between molecules, for example, a length. A compound having one or more structures in which chain hydrocarbon groups are linked. The linking moiety may be via a divalent or higher linking group containing a hetero atom, and the long chain hydrocarbon group may contain the same linking group and / or aromatic group. Specific examples of such a reversible developer are described in, for example, JP-A-9-290563 and JP-A-11-188969, and one or a mixture of two or more may be used.

In the reversible thermosensitive recording layer in the present invention, an additive for improving or controlling the coating properties and the color-decoloring / decoloring properties can be used as needed. These additives include, for example, surfactants, conductive agents, fillers, antioxidants, color stabilizers, and decolorization accelerators.

The reversible thermosensitive recording layer in the present invention is formed with a leuco dye, a color developer and various additives together with a binder resin. The resin used at this time only needs to be able to bind these materials on the support.
A mixture of two or more species may be used. Among them, a resin curable by heat, ultraviolet rays, electron beams, or the like is preferably used in order to improve durability during repetition, and a thermosetting resin using an isocyanate-based compound or the like as a cross-linking agent, for example, acrylic polyol Resin, polyester polyol resin, polyurethane polyol resin, polyvinyl butyral resin, resin having a group that reacts with a crosslinking agent such as cellulose acetate propionate, cellulose acetate butyrate, or a monomer having a group that reacts with a crosslinking agent and other monomers A resin obtained by copolymerizing the above is particularly preferably used. However, the invention is not limited to these compounds. The ratio of the coloring component to the resin in the recording layer is 0.1 to 0.1 with respect to the coloring component 1.
10 is preferred, and if it is less than this, the thermal strength of the recording layer becomes insufficient, and if it is more than this, there is a problem that the color density is lowered. Further, as a method for distinguishing whether the binder resin in the present invention is in a crosslinked state or in a non-crosslinked state, it can be distinguished by immersing the coating film in a highly soluble solvent. That is, the binder resin in a non-crosslinked state dissolves in the solvent and does not remain in the solute.

The curing agent used in the present invention is not particularly limited, but isocyanate curing agents are preferably used. As a specific example of the isocyanate-based curing agent, hexamethylene diisocyanate (HD
I), tolylene diisocyanate (TDI), xylylene diisocyanate (XDI), isophorone diisocyanate (IPDI), and the like, and adduct types, burette types, isocyanurate types, blocked isocyanates, and the like using trimethylolpropane and the like. Can be Among them, hexamethylene diisocyanate is particularly preferable, and the adduct type, buret type, and isocyanurate type are preferably used. However, the entire amount of the curing agent added may or may not have undergone a crosslinking reaction. That is, an unreacted curing agent may be present. Since this type of crosslinking reaction proceeds over time, the presence of unreacted curing agent does not indicate that the crosslinking reaction has not progressed at all, but that unreacted curing agent is detected. This indicates that the presence of a resin in a crosslinked state is suggested. Still further, a catalyst used in this type of reaction may be used as a crosslinking accelerator.

The reversible thermosensitive recording layer in the present invention is formed using a coating liquid prepared by uniformly mixing and dispersing a mixture comprising a leuco dye, a color developer, various additives, a binder resin and a coating liquid solvent. . Specific examples of the solvent used for preparing the coating liquid include alcohols, ketones, ethers, glycol ethers, esters, aromatic hydrocarbons, aliphatic hydrocarbons, and the like.
The present invention is not limited to these compounds.

The coating liquid was prepared by a paint shaker, a ball mill, an attritor, a three-roll mill, a Keddy mill,
It can be carried out using a known coating liquid dispersing apparatus such as a sand mill, a dyno mill, a colloid mill and the like. In addition, each material may be dispersed in a solvent using the above-described coating liquid dispersion device, or each material may be dispersed alone in the solvent and mixed. Further, it may be dissolved by heating and precipitated by rapid cooling or cooling.

The coating method in the present invention is not particularly limited, and includes blade coating, wire bar coating, spray coating, air knife coating, bead coating, curtain coating, gravure coating, kiss coating, and reverse coating. Known methods such as roll coating, dip coating, and die coating can be used.

The protective layer used in the present invention comprises, together with the solvent and the binder resin described above, an organic / inorganic filler,
An ultraviolet absorber, a lubricant, a coloring pigment, or the like can be used. Here, as the resin used for the protective layer, one or a combination of two or more conventionally known resins is used. Among them, a resin curable by heat, ultraviolet rays, electron beams, or the like is preferably used in order to improve durability during repetition, and a thermosetting resin using an isocyanate-based compound or the like as a cross-linking agent, for example, acrylic polyol Resin, polyester polyol resin, polyurethane polyol resin, polyvinyl butyral resin, resin having a group that reacts with a crosslinking agent such as cellulose acetate propionate, cellulose acetate butyrate, or a monomer having a group that reacts with a crosslinking agent and other monomers A resin obtained by copolymerizing the above is particularly preferably used. Further, a coating film can be prepared by using the above-described dispersing apparatus and coating method.

Further, the protective layer of the present invention becomes excellent in slipperiness by containing a silicon-modified polymer. As the silicon-modified polymer, a silicone block polymer, a silicone graft polymer, a silicone-modified acrylic polymer, a silicone-modified polyvinyl alcohol, and the like are preferable, and a silicone block polymer and a silicone graft polymer are particularly preferably used.

In the present invention, those having a Tg of 100 ° C. or higher and lower than 150 ° C. can be conveniently achieved by, for example, combining a suitable amount of a relatively soft material to be cross-linked and a cross-linking agent. The thickness of the anti-curl coating layer in the invention varies depending on the support and the like, but is generally preferably from 50 g / m ^{2 to} 0.10 g / m ² . Even if the thickness exceeds 50 g / m ² , not only the curl prevention effect may not be further increased correspondingly, but also the degree of cross-linking and the properties may differ between the layer surface and the inside of the layer.
If the coating amount is less than 0.10 g / m ² , the curl preventing effect may not be obtained.

Further, in the present invention, the improvement of the color development sensitivity,
An under layer may be provided for improving the adhesiveness. Further, the adhesion between the recording layer and the protective layer is improved, the deterioration of the recording layer due to the application of the protective layer is prevented, the material contained in the protective layer is transferred to the recording layer, or the material contained in the recording layer is transferred to the protective layer. In order to prevent this, an intermediate layer may be provided between the two. In these layers, together with the solvent and the binder resin described above, an organic / inorganic filler, an ultraviolet absorber, a lubricant, a coloring pigment, and the like can be used, and the coating film is formed using the dispersing apparatus and the coating method described above. Can be produced.

Specific examples of the inorganic filler include carbonate,
Silicates, metal oxides, sulfate compounds and the like, specific examples of the organic filler, silicone resin, cellulose resin, epoxy resin, nylon resin, phenol resin, polyurethane resin, urea resin, melamine resin, polyester resin, Polycarbonate resins, styrene resins, acrylic resins, polyethylene resins, formaldehyde resins, polymethyl methacrylate resins, and the like. Specific examples of the ultraviolet absorber include compounds having a salicylate structure, a cyanoacrylate structure, a benzotriazole structure, a benzophenone structure, and the like. Specific examples of the lubricant include synthetic waxes, vegetable waxes, animal waxes, higher alcohols, higher fatty acids, higher fatty acid esters, and amides. However, the present invention is not limited to these compounds.

The reversible thermosensitive recording layer in the present invention is colored and decolored by the process shown in FIG. Heating the initial colorless state (A) the temperature above T ₁ in leuco dye and the developer are colored by mixing and melting (B), the colored state is fixed to quench this state. Heating the color-developed state (C), and decolored at a lower temperature T ₂ than the coloring temperature, the initial and the same decolored state if cooled. Thus, recording and erasing of the recording layer can be performed by controlling the heating temperature and the cooling rate after heating.

The reversible thermosensitive recording medium of the present invention is provided with both a thermoreversible recording section and an information storage section, so that the information stored in the information storage section is displayed on the thermoreversible recording section. Information can be checked without any equipment.
Convenience is improved. As the storage unit used at that time, a magnetic recording layer, an IC recording unit, or the like is preferably used.

Further, these can be processed into a shape according to the application, and are processed into a card shape, a sheet shape, a roll shape and the like. A card-shaped sheet can be applied to a prepaid card, a point card, and a credit card. A sheet-shaped sheet such as an A4 size sheet can be processed by using a printing / erasing device. , As well as trial printing,
It can be widely used for temporary output such as circulation documents and meeting materials. Furthermore, what is processed into a roll shape,
It can be used for a display board, a bulletin board, or an electronic blackboard by being incorporated in a device having a printing / erasing section. Since such a display device does not generate dust and dirt, it can be preferably used in a clean room or the like.

The reversible thermosensitive recording medium of the present invention may use an irreversible thermosensitive recording layer in combination. At this time, the color tone of each recording layer may be the same or different. Further, a part or the entire surface of the reversible thermosensitive recording medium of the present invention, offset printing, printing such as gravure printing, or an inkjet printer, a thermal transfer printer, even if provided with a colored layer subjected to any pattern by a sublimation printer or the like In addition, an OP varnish layer containing a curable resin as a main component may be provided on a part or the entire surface of the coloring layer. These supports may have a magnetic recording layer on the same side as the reversible thermosensitive recording layer and / or on the opposite side.

[0043]

When the reversible thermosensitive recording medium of the present invention is provided with a rewritable barcode, it is preferable to provide a layer for regularly reflecting light on the back of the thermosensitive layer. . By providing a layer for regularly reflecting light, the degree of white turbidity of the white turbid portion is improved, and consequently, the contrast is improved, and the reading accuracy of the barcode can be improved.

When the reversible recording medium of the present invention is provided with both rewritable barcodes and images, characters, numbers, and the like which are visually recognized by humans, the two types having different reflectances are used.
It can consist of more than one kind of site. That is, it is preferable to provide the above-mentioned light reflecting layer on the back surface of the rewritable barcode, and to provide a light absorbing layer, that is, a coloring layer, on the back surface of the part viewed by humans. This is because when viewed by a human, for example, there is a color tone difference in addition to a light amount difference between an image portion in a cloudy state and a non-image portion in a colored state, and depending on the viewing angle, excessive The glare caused by reflected light is eliminated, making it easier to see a reversible visible image.On the other hand, when reading this image with a device such as a reflection densitometer or a bar code reader, light is normally incident obliquely. The sensor is placed and read in the direction perpendicular to the surface, because the color layer absorbs at least a part of the visible light and lowers the contrast to measure the result. Therefore, the colored layer in the reversible thermosensitive recording medium of the present invention is composed of two or more types of portions having different reflectances with respect to visible light, and at least one of the portions is a layer that absorbs visible light. Partly made of a layer that reflects visible light, it is easy to recognize the image visually,
In addition, high contrast can be obtained even by measurement using an apparatus.

For example, as shown in FIG. 2 (a), the reversible thermosensitive recording medium of the present invention comprises a support (11) provided with a reversible thermosensitive recording layer (13) and a protective layer (14). Film, as shown in FIG.
A reversible thermosensitive recording layer (13) and a protective layer (14) are provided thereon, and a magnetic recording layer (16) is provided on the back surface of the support (11). The back layer (15) can be provided on the layer (16), and the back layer (15) can be omitted by simultaneously providing the magnetic recording layer (16) with the same function as the back layer (15). As shown in FIG. 3, these sheets or films can be processed into, for example, an A4 size sheet (18) having a print display section (19). In this case, the magnetic recording section (20) Is the sheet (1
8) It can be provided only in one part region or in the whole region.

Further, as shown in FIG. 4A, a reversible thermosensitive recording layer (13) is provided on a support (11).
The film provided with the protective layer (14) may be processed into a sheet shape to form a recess (23) for accommodating an IC chip, and may be processed into a sheet shape. In this example, a print display section (19) is provided on a sheet-like reversible thermosensitive recording medium, and a recess (2) for embedding an IC chip is provided at a predetermined location on the back side of the reversible thermosensitive recording medium.
3) is formed, and this recess (23) is formed in FIG.
A wafer (231) as shown in (b) is assembled and fixed. The wafer (231) is a wafer substrate (23
2) An integrated circuit (233) is provided thereon, and a plurality of contact terminals (234) electrically connected to the integrated circuit (233) are provided on the wafer substrate (232). The contact terminals (234) are exposed on the back side of the wafer substrate (232), and a dedicated printer (reader / writer) electrically contacts the contact terminals (234) to read or rewrite predetermined information. It is configured to be able to. One example of the function of this reversible thermosensitive recording sheet is as follows:
This will be described with reference to FIG.

FIG. 5A is a schematic block diagram showing an integrated circuit (233), and FIG. 5B is a block diagram showing an example of data stored in a RAM. The integrated circuit (233) is composed of, for example, an LSI, and includes a CP capable of executing a control operation in a predetermined procedure.
U (235), a ROM (236) for storing operation program data of the CPU (235), and a RAM (237) for writing and reading necessary data.
Further, the integrated circuit (233) receives the input signal and
(235) and the CPU (23).
5) an input / output interface (238) for receiving an output signal from the device and outputting the signal to the outside, a power-on reset circuit, a clock generator, a pulse divider (interrupt pulse generator), and an address decoder (not shown) Circuit. The CPU (235) can execute the operation of the interrupt control routine in accordance with the interrupt pulse periodically given from the pulse dividing circuit. The address decode circuit decodes the address data from the CPU (235) and provides signals to the ROM (236), the RAM (237), and the input / output interface (238).
A plurality of (eight in the figure) contact terminals (234) are connected to the input / output interface (238), and predetermined data from the dedicated printer (reader / writer) is input from the contact terminals (234). Output interface (2
38) to the CPU (235). CPU
(235) responds to the input signal and outputs the data from the ROM (23)
According to the program data stored in 6), each operation is performed, and predetermined data and signals are output to the sheet reader / writer via the input / output interface (238).

As shown in FIG. 5B, the RAM (2
37) includes a plurality of storage areas (239a) to (239g). For example, the area (239a) stores a sheet number, and the area (239b) stores ID data such as the name, affiliation, and telephone number of the sheet manager.
In c), for example, information on the residual margin or handling that can be used by the user is stored, and the area (239d) (239)
e) (239f) and (239g) are former management officers,
Information about the previous user is stored.

Printing on the reversible thermosensitive recording medium of the present invention can be performed by a thermal head in the same manner as ordinary thermosensitive recording, and erasing is performed by a heating element such as a temperature controlled heat roller, a ceramic heater, and a thermal head. Therefore, a small and simple rewriting recording apparatus can be used, and for example, the apparatus shown in FIGS. 6, 7, and 8 can be used.

In the reversible thermosensitive recording apparatus of FIG. 6, a reversible thermosensitive recording medium (1) provided with a magnetic recording layer on the opposite side of the thermosensitive layer is conveyed along a conveying path shown by a reciprocating arrow. Alternatively, the sheet is transported in the reverse direction in the apparatus along the transport path. The reversible thermosensitive recording medium (1) has a magnetic head (3
4) and the transport roller (31), magnetic recording or recording is performed on the magnetic recording layer, and a heating process for erasing an image is performed between the ceramic heater (38) and the transport roller (40), and the thermal head (53) and the transport roller The image is formed between (47) and then carried out of the apparatus. As described above, the set temperature of the ceramic heater (38) is preferably 110 ° C. or higher, more preferably 112 ° C. or higher, and 115 ° C.
The above is particularly preferred. However, rewriting of magnetic recording may be performed before or after image erasure by the ceramic heater. If desired, a ceramic heater (3
8) and after passing between the transport roller (40) or after passing between the thermal head (53) and the transport roller (47), the sheet is transported in the reverse direction through the transport path, and is again subjected to heat treatment by the ceramic heater (38). The printing process can be performed again by the head (53).

In the reversible thermosensitive recording apparatus of FIG. 7, the reversible thermosensitive recording medium (1) inserted from the entrance (30).
Travels along a transport path (50) shown by a dashed line, or travels in a reverse direction in the apparatus along the transport path (50). The reversible thermosensitive recording medium (1) inserted from the entrance (30) is transported in the recording apparatus by the transport roller (31) and the guide roller (32), and is transported by the transport path (50).
Is reached by the sensor (33) through the control means (34C), and the magnetic recording or recording is performed on the magnetic recording layer between the magnetic head (34) and the platen roller (35). The guide roller (39) passes between the roller (36) and the transport roller (37).
And an image erasing operation between the platen roller (44) and the ceramic heater (38), which passes between the conveying rollers (40) and recognizes the presence thereof by the sensor (43) through the ceramic heater control means (38C) and operates. The transfer roller (4) is subjected to a heat treatment, and is controlled by a rotation control means (not shown) (control of rotation speed and rotation direction including stop).
5) The thermal head (50) which is transported in the transport path (50) by (46) and (47), and operates by recognizing the presence thereof at a predetermined position by the sensor (51) via the thermal head control means (53C). 53) and a platen roller (5
An image is formed between 2) and a conveying roller (59) is controlled from a conveying path (56a) (controlled by rotating means (not shown)).
And, it is carried out of the apparatus via the outlet (61) by the guide roller (60). Reference numeral (38a) indicates a temperature sensor for the ceramic heater (38), and reference numeral (53a) indicates a temperature sensor for the thermal head (53). Here, as described above, the set temperature of the ceramic heater (38) is preferably 110 ° C. or higher, more preferably 112 ° C. or higher, and particularly preferably 115 ° C. or higher.

If desired, the transfer path switching means (55
a) is led to the transport path (56b) by switching
The reversible thermosensitive recording medium (1) is moved in the opposite direction to the input of the limit switch (57a) by pressing the reversible thermosensitive recording medium (1), and the reversible thermosensitive recording medium is rotated by a control means (not shown). The recording medium (1) is again transferred to the thermal head (53) and the platen roller (5).
After the heat treatment between 2), the transport path (49b), the limit switch (57b), and the transport belt (48) whose rotation speed is controlled by control means (not shown) are opened by switching the transport path switching means (55b). Through the transport path (56a), and can be carried out of the apparatus via the outlet (61) by the transport roller (59) and the guide roller (60). Further, such a branched transport path and transport switching means are provided with a ceramic heater (3.
8), the sensor (43) can be provided on both sides of the platen roller (44) and the transport roller (4).
It is desirable to provide between 5).

In the recording apparatus and recording method for a reversible thermosensitive recording medium according to the present invention shown in FIG. 8, the rewriting recording apparatus detects a mark indicating the printing direction, which is provided on both sides of the recording medium, and accordingly, The recording device determines the printing direction and prints the document. In addition, the reversible thermosensitive recording (document rewriting) apparatus of the present invention is a reversible thermosensitive recording (document rewriting).
A recording (rewriting) apparatus capable of using a reversible thermosensitive recording (document rewriting) medium that can record on both sides of a medium and has no limitation on the recording direction on either side, and is a reversible thermosensitive recording (document rewriting). Replacement) with / with sign displayed or processed on the medium
A first signal detection mechanism for detecting absence and issuing a marker presence / absence signal for activating a second detection mechanism when present, and operating when the marker presence / absence signal is input to identify the direction of the marker A second signal detection mechanism for emitting two types of sign direction signals, and opening the first conveyance path leading to the printing means when one of the two kinds of sign direction signals is input. And a conveyance path switching unit that closes when the other signal is input, and a unit that cuts off a current supply circuit to the printing unit when the other signal is input.

That is, in the reversible thermosensitive recording (document rewriting) apparatus shown in FIG. 8, the reversible thermosensitive recording medium (71) inserted from the insertion port (70) is moved to the first position by the transport belt (73). The paper is transported along the transport path (72), or is returned in the apparatus in the reverse direction along the first transport path (72) or (85). A thermal head (88) as a printing unit is provided in the middle of the first transport path (85). First, the reversible thermosensitive recording medium (71) inserted from the insertion port (70) is conveyed in the recording apparatus by the conveyance belt (73) and the guide roller (74), and is positioned at a predetermined position on the first conveyance path (72). Is reached, a magnetic force is applied to the magnetic recording layer between the magnetic head (76) and the platen roller (77) of the magnetic recording apparatus for magnetic recording on the magnetic recording layer area that may be omitted via the control means (75). The data is recorded or erased, and further conveyed along the first conveyance path (72) by the conveyance belt (78). At a predetermined position, the control means (8
The presence / absence of the presence of the marker is detected via a first sensor (79) as a first signal detection mechanism having (0), and a second sensor (81) having a control means (82) when it is present.
Is issued to activate the signal. The presence of the sign means that the first reversible thermosensitive recording medium (71)
This means that the document information and the mark are printed on the surface. This marker presence / absence signal is input to a second sensor (81) as a second signal detection mechanism, whereby the second sensor (81) operates to identify the direction of the marker.
It emits different sign direction signals. One of the sign direction signals indicating that the direction of the reversible thermosensitive recording medium (71) is the correct direction is operated by the operation unit (not shown) by the conveyance path switching unit (84), and the control unit (87) ), The first transport path (85) leading to the thermal head (88) as a printing means is opened, and the second transport path (9) is opened.
2) Close. The other sign direction signal indicating that the direction of the reversible thermosensitive recording medium (71) is in the wrong direction closes the first transport path (72) and closes the second transport path (9).
Open 2). Further, the other sign direction signal is inputted to a switch of an energizing circuit (not shown) to a thermal head (88) as a printing means to shut off the energizing circuit. The reversible thermosensitive recording medium (71) conveyed to the first conveyance path (85) is conveyed by a conveyance belt (86), and operates at a predetermined position via a thermal head control means (87). (88) and the platen roller (8)
9), and is carried out of the apparatus via the first outlet (91) by the conveyor belt (90). On the other hand, as a result of monitoring the sign, the second conveyance path (9
The reversible thermosensitive recording medium (71), which has been conveyed in (2) and on which the document information and the mark are already printed on the first side, operates the limit switch (93) which is input by pressing the reversible thermosensitive recording medium (71). , And is conveyed in the reverse direction through the second conveyance path (92) by the conveyance belt (94) whose rotation speed and direction are controlled by control means (not shown). 84), and is conveyed in the opposite direction by a conveyance belt (78) whose rotation speed and direction is controlled by a control means (not shown), and by a similar conveyance belt (73), and out of the apparatus through the insertion port (70). It is carried out (returned). As described above, the thermal head (88) operates only when the reversible thermosensitive recording medium (71) is determined to be an unrecorded medium or when the information recording surface and the insertion direction are determined to be correct. The energization is controlled by control means (not shown), and the heating is performed.

In the reversible thermosensitive recording (document rewriting) apparatus of the present invention shown in FIG. 8, when the reversible thermosensitive recording medium (71) is inserted in the wrong direction, it is printed by the printing means (8).
8) It is preferable to have a means for carrying out of the apparatus without making contact with the apparatus, and therefore, the conveyance path switching means (84) is provided with the first path leading to the printing means (88).
And a second conveyance path (92) for carrying out the recording medium outside the apparatus, bypassing the printing means (88). The transport end of the second transport path (92) may be connected to the first transport port (91) of the first transport path (72) or (85), and the first transport port may be connected to the first transport port (91). A second carry-out port different from (91) may be provided.
As described above, the second transport path (92) can be provided with a means for reversely feeding the reversible thermosensitive recording medium (71) transported here in the direction of the carry-in port (70), In that case, there is no need to provide the second carry-out port. Further, when the reversible thermosensitive recording medium (71) is inserted in the wrong direction and is led to the second transport path (92), the reversible thermosensitive recording medium is not affected by the power saving purpose and the residual heat in the apparatus. For this reason, the power supply circuit to the printing means (88) can be automatically cut off.

FIG. 9 shows an example of a control circuit for a ceramic heater and a thermal head having a means for finely adjusting the amount of energization in the apparatus related to the above-described example of the recording apparatus of the present invention. In this example, the transistor (TR11) and the transistor (TR12) form a first self-running multivibrator for the ceramic heater (38), and the (TR11) and (TR12) are alternately turned on, and the transformer is turned on. A secondary induction output of a high voltage corresponding to the alternating input to the primary coil (L11) is obtained in the secondary coil (L21), and this is used as the load (R1) and the resistances (R1) and (R11) are obtained. Ceramic heater (3
The power supply of 8) is used to carry out pulsed heating, and the self-running multivibrator circuit is controlled by a transistor (TR1), a resistor (Rx),
Thermistor (SM1) of temperature sensor (38a)
And a feedback circuit that has a negative input / output relationship with respect to a load change of the self-running multivibrator circuit. To add about the self-propelled multivibrator,
When one transistor, for example, (TR11) conducts, the primary coil (L11) of the transformer conducts, and as a result,
A secondary induction output is obtained in the secondary side coil (L21) for a short time, and is used as a heater source. At the same time, the secondary output is generated in the coil (L11) a little later by the secondary output. I got the output and got this time to get 3
The next output is fed back to the other transistor (TR12) this time to make it conductive so that the transistor (TR1) is turned on.
In the case of 2), the same operation as in the case of the transistor (TR11) is performed, and this operation is repeated alternately thereafter to obtain a multivibrator. Capacitor (C
1) cooperates with the coil (L11) in the circuit to determine the conduction time constant of both transistors (that is, the frequency of pulse conduction), and of course, the power supply of this circuit is supplied from the rectifier (D). Is applied.

The same applies to the second self-propelled multivibrator including the thermal head (53) and the thermistor (SM2) of the temperature sensor (53a) in FIG. The switch (SW) can switch the ceramic heater (38) between a high calorific value (R1 + R11) and a low calorific value (R1 only).
2 + R12) and a low heat value (only R2). In addition, known means for protecting the circuit elements from surge voltage can be combined, for example, a resistor (R3) for a rectifier (D).
In order to protect the rectifier (D) from a sudden overvoltage current, an overcurrent bypass path is provided by arranging a Zener diode that conducts when the Zener breakdown voltage is reached in parallel with the resistor (R3) + the rectifier (D). be able to. This circuit device has an advantage of not only a pulse output, but also not including a general high time constant back electromotive force absorption circuit such as a diode and a resistor.

FIG. 10 shows still another example of the means for finely adjusting the amount of energization in the apparatus of the present invention. FIG.
The power supply amount adjusting means (103) in (1) is an input means (104) for inputting information for controlling the recording (rewriting) apparatus of the present invention, and a judging / comparing means for controlling the ceramic heater (38). (105) and determination / comparison means (106) for controlling the thermal head (53).
And the thermistor (SM1) of the first temperature sensor (38a)
And the thermistor (SM2) of the second temperature sensor (53a)
Rewriting device control means (107) for controlling the apparatus of the present invention; timer input means (108) for producing a reference clock for the integrated time of the ceramic heater (38) and thermal head (53); ) And a data memory (109) for counting the accumulated time of the thermal head (53), performing zero payment and recounting,
The first temperature sensor (SM1) and the second temperature sensor (SM
It comprises a controller (110) for controlling the entire heating system of the apparatus in a certain sequence based on information from 2) and information from the data memory (109), and a memory (111) storing the sequence.

The clock signal input by the timer input means (108) is taken into the controller (110), and the clock signal is compared with the determination / comparison means (10).
Heating data in the ceramic heater (38) by 5) is taken in as an output temperature signal of the judging / comparing means (105), and the clock signal and printing heating data by the judging / comparing means (106) are judged by the judging / comparing means ( 106) is taken in as the output temperature signal. And a memory (111) for storing a certain sequence.
The controller (110) is activated by a signal from
By the controller (110), the rewriting device control means (107) can control the ceramic heater relay (CR1) for pulse conduction to the ceramic heater (38),
And a thermal head relay (CR2) for energizing the thermal head (53) with a pulse, for example, ON-OFF.
Control. More specifically, the controller (110) is realized by a one-chip microcomputer also including a memory (111) and a data memory (109), and the input means (104) includes a control input switch (113a),
The input signal is input to the microcomputer by (113b).
Further, as the determination / comparison means (105) of the ceramic heater (38), the intermediate input voltage of the series circuit composed of the temperature-sensitive resistance element (SM1) and the thermovolume (114), the resistance (115), and the resistance (116) A comparator (1) for comparing and detecting a reference voltage which is an intermediate voltage connected in series
The determination and comparison are performed according to (17), and the microcomputer (12) determines the current temperature of the ceramic heater (38).
5) is input as a digital output signal indicating whether it is "H" or "L". The resistor (118) is a resistor for a thermo differential value for providing an ON point and an OFF point in the thermo volume (114) for setting a temperature.

As shown in FIG. 11, the power supply circuit of this control circuit is composed of an AC power supply (126), a rectifier (D), a capacitor (129), etc., and the timer control circuit (130) This is for controlling the timer circuit inside the microcomputer (125). In the figure, a microcomputer (125) has a power supply terminal (VD), an output terminal for output for operating the determination / comparison means (105) via an input switch (113a), and an input switch (113).
b) an output terminal for output for operating the judging / comparing means (106), and as input ports, an input port (AΦ) for inputting an output of the comparator (117) and a comparator (123) Input port (BΦ) for inputting the output of the timer, a timer control circuit (130)
The input port (CΦ) for inputting the output of the transistor (TR), the output port (DΦ) for outputting to the base electrode of the transistor (TR1) as the output port, and the transistor (TR)
Output port (EΦ) for output to base electrode in 2)
There is. The microcomputer (125) starts operation with a DC power supply from the power supply terminal (VD), and the control input switch (113).
a) The operation control mode is selected by the ON-OFF signal of (113b).

Referring to FIG. 11, regarding the control inside the microcomputer, when the control input switch (113a) is turned on (113
Explaining the case where b) is OFF. When the rewriting device is energized and the ceramic heater (38) is heated and reaches the OFF point of the thermo differential (Δt), the output of the comparator (117) is output. That is, an "L" signal is output to the Aφ port of the microcomputer (125).
At the same time, an L (low) signal is output from the output terminal Dφ port to disconnect the relay (CR1), and the timer input means (10
The clock signal from 8) is counted in the data memory (111), and when the value counted in the data memory (111), that is, the power-supply stop time elapses a predetermined initial setting time (t1), the Dφ port is Outputs an H (high) signal to forcibly turn on and start energization. At the same time, the integration time in the data memory (109) is set to zero, and the integration of the next energization time is started. When this energization time elapses a predetermined period (t0), a low level is applied to the Dφ port.
When a (low) signal is output, the relay (CR1) is forcibly disconnected to stop energization. With this apparatus, the power supply time (t0) and the power supply stop time (t1) can be adjusted and set in advance, respectively, and the “offset point” and the ON point of the thermo differential (Δt) can be set according to “this adjustment setting”. A point can be defined, and the width of the thermo differential (Δt) can also be pre-selected as the difference between the OFF point and the ON point.

In this apparatus, the judgment / comparison means (105) and (106) and the comparators (117) and (123) have been described as being separate in order to facilitate understanding of the present invention. A control input switch (113a) is turned on and off to the microcomputer through the input means (104).
By controlling, the determination / comparison means (105) and the comparator (117) and the determination / comparison means (106)
And the comparator (123).

FIG. 12 shows the state of the energizing pulse and the temperature change of the ceramic heater (38). First, in accordance with the heating timing based on the output signal of the position detection sensor (43), before the reversible thermosensitive recording medium (1) reaches the ceramic heater (38) for color heating, the reversible thermosensitive recording medium is used. (1) is heated to a temperature (T1) to rapidly heat the ceramic heater (38). When the reversible thermosensitive recording medium arrives, the ceramic heater (38) heats the recording medium to a temperature (T1) and is at a temperature at which a color can be formed. Thereafter, a continuous constant energizing pulse is applied to the ceramic heater (38). To maintain the temperature to develop the color of the recording medium.

In this example, the cycle (C) of the energizing pulse is
Is set to 10 ms, and the energizing time P is set to 9
When a predetermined number of energizing pulses are applied as ms, the temperature of the ceramic heater (38) for full-color heating is rapidly increased, and the temperature reaches a temperature at which the ceramic heater (38) can color the entire reversible thermosensitive recording medium. And the energizing time is 2ms
Then, heating is performed so as to maintain the temperature, and the energization is terminated after applying a number of energization pulses corresponding to the length of the reversible thermosensitive recording medium (1).

FIG. 13 is a diagram showing the processing contents of the energizing pulse by the controller (110). The number of pulses of a series of energizing pulses is Nn, the energizing cycle is Cn, and the energizing time is Pn
And These data (Nn, Cn, Pn) are previously stored in R
The data (Nn, Cn, P) is written in an OM (read only memory) (141) and given an address signal from the controller (110) to the ROM.
n) is read out and sequentially sent to the register section (143) and the data latch section (144). This register section (14
3) The data latch section (144) is controlled by the controller (110), the data Nn is sent to the N pulse counter section (145), and the data (Cn, Pn) is sent to the energization time creation counter section (146). Sent.

This energization time creation counter section (146)
Determines the energizing time for one pulse based on the data (Cj, Pk), and inputs the output data to the driver unit (147). The driver unit (147) outputs an energizing pulse corresponding to the energizing time data to output the ceramic heater (3).
8) is driven. At the same time, the N pulse counter unit (1
45) counts the number of energized pulse outputs and outputs data N
The controller (110) at the time of counting i
Send a signal to

Thus, the controller (110)
Outputs an address signal in the next cycle and controls the register section (143) and the data latch section (144). For example, in the present invention, Cn is constant at 10 ms, P0 = 9 ms and N0 = 30 at temperature rise, and P1 = 2 ms and N1 = 213 to 21 at constant temperature control.
5 can be set. The energization time in each mode,
The number of pulses is set based on data collected in advance.

[0068]

The present invention will be described in more detail with reference to the following examples. In the examples, “parts” and “%” are based on weight. Example 1 <Preparation of Recording Layer Liquid> 3 parts of a developer having the following structural formula

[0069]

Embedded image Dialkyl urea (manufactured by Nippon Kasei Co., Ltd., Hakclean SB) 1 part Acrylic polyol 50% solution (manufactured by Mitsubishi Rayon Co., Ltd., LR327) 9 parts Methyl ethyl ketone 70 parts The above composition is pulverized using a ball mill to an average particle size of about 1 μm. Dispersed. 2-anilino-3-methyl-6-dibutylaminofluorane 1 part Isocyanate (Nippon Polyurethane Co., Coronate HL) 3 parts The above composition is added to a dispersion obtained by pulverizing and dispersing a developer, and the mixture is stirred well and applied to the recording layer. A liquid was prepared.

<Preparation of Protective Layer Liquid> Acrylic polyol 50% solution (manufactured by Mitsubishi Rayon Co., Ltd., LR327) 20 parts Isocyanate-based curing agent (manufactured by Nippon Polyurethane Co., Coronate HL) 9 parts Filler (manufactured by Mizusawa Chemical Co., Ltd., P832) 5 Part methyl ethyl ketone 40 parts The above composition was pulverized and dispersed using a ball mill so that the average particle size became about 1 μm. Filler amount is protective layer resin 1
22 parts by weight with respect to 00 parts by weight.

<Preparation of a reversible thermosensitive recording medium> The coating solution for the recording layer having the above composition was applied on a coated paper having a thickness of 100 μm using a wire bar, dried at 100 ° C. for 2 minutes, and dried.
C. for 24 hours at a film thickness of about 10 g / m ^2.
Was provided. Further, a protective layer coating solution of the above composition,
The recording layer was coated with a wire bar, dried at 100 ° C. for 2 minutes, and cured at 60 ° C. for 24 hours to form a protective layer having a thickness of about 3 g / m ² .

Example 2 <Adjustment of Recording Layer Liquid> Adjustment was carried out in the same manner as in Example 1. <Preparation of protective layer liquid> Acrylic polyol 50% solution (LR327, manufactured by Mitsubishi Rayon Co., Ltd.) 20 parts Isocyanate curing agent (Nippon Polyurethane Co., Coronate HX) 4 parts Filler (Mitsuzawa Chemical Co., P832) 1 part Silicone polymer (Manufactured by Nippon Yushi Co., Ltd., FS700) 1 part Methyl ethyl ketone 26 parts The above composition was averaged to a particle size of about 0.5 μ using a ball mill.
m and then pulverized and dispersed. The filler amount was 6 parts by weight based on 100 parts by weight of the protective layer resin. <Preparation of reversible thermosensitive recording medium> Adjustment was performed in the same manner as in Example 1.

Example 3 <Adjustment of Recording Layer Liquid> Adjustment was carried out in the same manner as in Example 1. <Preparation of protective layer liquid> Acrylic polyol 50% solution (manufactured by Mitsubishi Rayon Co., Ltd., LR327) 20 parts Isocyanate-based curing agent (Nippon Polyurethane Co., Ltd., Coronate HX) 4 parts Filler (Mizusawa Chemical Co., Ltd., P832) 12 parts Silicone polymer (Manufactured by Nippon Yushi Co., Ltd., FS700) 1 part Methyl ethyl ketone 51 parts The above composition was averaged to a particle size of about 0.5 μ using a ball mill.
m and then pulverized and dispersed. The filler amount was 45 parts by weight based on 100 parts by weight of the protective layer resin. <Preparation of reversible thermosensitive recording medium> Adjustment was performed in the same manner as in Example 1.

Example 4 <Adjustment of Recording Layer Liquid> Adjustment was carried out in the same manner as in Example 1. <Preparation of protective layer solution> Polyester resin (manufactured by Dainippon Ink and Chemicals, DE-140-70) 14 parts Isocyanate-based curing agent (manufactured by Nippon Polyurethane Co., Coronate HX) 3 parts Filler (manufactured by Mizusawa Chemical Company, P832) 1 part Silicone polymer (manufactured by NOF CORPORATION, FS700) 1 part Methyl ethyl ketone 29 parts The above composition was averaged to a particle size of about 2.6 μ using a ball mill.
m and then pulverized and dispersed. The filler amount was 7 parts by weight based on 100 parts by weight of the protective layer resin. <Preparation of reversible thermosensitive recording medium> Adjustment was performed in the same manner as in Example 1.

Example 5 <Adjustment of Recording Layer Liquid> Adjustment was carried out in the same manner as in Example 1. <Preparation of protective layer liquid> Acrylic polyol 50% solution (manufactured by Mitsubishi Rayon Co., Ltd., LR327) 20 parts Isocyanate curing agent (manufactured by Nippon Polyurethane Co., Coronate HL) 9 parts Filler (Mizusawa Chemical Company, P832) 14 parts Silicone polymer (Manufactured by Nippon Yushi Co., Ltd., FS700) 1 part Methyl ethyl ketone 61 parts The above composition was averaged to a particle size of about 2.6 μ using a ball mill.
m and then pulverized and dispersed. The filler amount was 45 parts by weight based on 100 parts by weight of the protective layer resin. <Preparation of reversible thermosensitive recording medium> Adjustment was performed in the same manner as in Example 1.

Example 6 <Adjustment of Recording Layer Liquid>
became. <Preparation of Intermediate Layer Liquid> Acrylic polyol 50% solution (LR503, manufactured by Mitsubishi Rayon Co., Ltd.) 20 parts Isocyanate-based curing agent (Nippon Polyurethane Co., Ltd., Coronate HX) 2 parts Tetrahydrofuran 38 parts <Preparation of protective layer liquid> Acrylic polyol 50 % Solution (manufactured by Mitsubishi Rayon Co., Ltd., LR327) 20 parts Isocyanate-based curing agent (manufactured by Nippon Polyurethane Co., Coronate HL) 9 parts Filler (manufactured by Mizusawa Chemical Co., Ltd., P832) 5 parts Methyl ethyl ketone 40 parts The above composition was ball-milled. Average particle size of about 1μm
And pulverized and dispersed. Filler amount is protective layer resin 1
22 parts by weight with respect to 00 parts by weight. <Production of reversible thermosensitive recording medium> Coating solution for recording layer having the above composition
Using a wire bar on a coated paper having a thickness of 100 μm.
And dried at 100 ° C for 2 minutes, then at 60 ° C for 24 hours
To a film thickness of about 10 g / m^TwoRecording layer
I did. Next, an intermediate layer coating solution having the above composition is applied onto the recording layer.
Apply using an ear bar, dry at 100 ° C for 2 minutes
About 1 g / m thickness ^TwoWas provided. Further, the above composition
A protective layer coating solution is coated on the intermediate layer using a wire bar.
Cloth, dried at 100 ° C for 2 minutes, and dried at 60 ° C for 24 hours.
About 3 g / m^TwoWas provided.

Comparative Example 1 <Adjustment of Recording Layer Liquid> Adjustment was carried out in the same manner as in Example 1. <Preparation of Protective Layer Liquid> Acrylic polyol 50% solution (LR327, manufactured by Mitsubishi Rayon Co., Ltd.) 20 parts Isocyanate-based curing agent (Nippon Polyurethane Co., Coronate HX) 4 parts Filler (Showa Denko KK, AL-150SG) 9 parts Silicone polymer (manufactured by NOF CORPORATION, FS700) 1 part Methyl ethyl ketone 44 parts The above composition was pulverized and dispersed using a ball mill so as to have an average particle size of about 1 μm. Filler amount is protective layer resin 1
38 parts by weight with respect to 00 parts by weight. <Preparation of reversible thermosensitive recording medium> Adjustment was performed in the same manner as in Example 1.

Comparative Example 2 <Adjustment of Recording Layer Liquid> Adjustment was performed in the same manner as in Example 1. <Preparation of protective layer liquid> Acrylic polyol 50% solution (manufactured by Mitsubishi Rayon Co., Ltd., LR327) 20 parts Isocyanate-based curing agent (Nippon Polyurethane Co., Coronate HX) 4 parts Filler (Ube Materials Co., Ltd., C type) 6 parts Silicone polymer (manufactured by NOF Corporation, 1 part) FS700 1 part Methyl ethyl ketone 38 parts
m and then pulverized and dispersed. The filler amount was 30 parts by weight based on 100 parts by weight of the protective layer resin. <Preparation of reversible thermosensitive recording medium> Adjustment was performed in the same manner as in Example 1.

Comparative Example 3 <Adjustment of Recording Layer Liquid> Adjustment was performed in the same manner as in Example 1. <Preparation of Protective Layer Liquid> Acrylic polyol 50% solution (manufactured by Mitsubishi Rayon Co., Ltd., LR327) 20 parts Isocyanate-based curing agent (manufactured by Nippon Polyurethane Co., Coronate HL-S) 14 parts Silicone polymer (manufactured by NOF Corporation, FS700) 2 Part: methyl ethyl ketone: 34 parts <Preparation of reversible thermosensitive recording medium> The preparation was performed in the same manner as in Example 1.

Comparative Example 4 <Adjustment of Recording Layer Liquid> Adjustment was carried out in the same manner as in Example 1. <Preparation of Protective Layer Liquid> Vinyl chloride-vinyl acetate copolymer (manufactured by Denki Kagaku Co., Ltd., # 1000CM) 20 parts Methyl ethyl ketone 47 parts <Preparation of reversible thermosensitive recording medium> A recording layer coating liquid having the above composition was coated to a thickness of 100 μm. Was coated with a wire bar, dried at 100 ° C. for 2 minutes, and cured at 60 ° C. for 24 hours to form a recording layer having a thickness of about 10 g / m ² . Further, a protective layer coating solution having the above composition was applied onto the recording layer using a wire bar, and dried at 100 ° C. for 2 minutes to form a protective layer having a thickness of about 3 g / m ² .

The reversible thermosensitive recording media prepared in Examples 1 to 6 and Comparative Examples 1 to 4 were tested by the following evaluation methods, and the results are shown in Table 1.

Test 1: Measurement of dynamic friction coefficient Measurement was performed using a static / dynamic friction measuring device (manufactured by Kyowa Interface Science Co., Ltd.).

Test 2: Measurement of surface glossiness The glossiness of the reversible thermosensitive recording medium was measured using a variable angle glossmeter (manufactured by Nippon Denshoku Industries Co., Ltd.) at an incident / reflection angle of 60 degrees.

Test 3: Peak temperature of logarithmic decay rate and logarithmic decay rate at peak temperature Samples were prepared according to the method described above, and the peak temperature of logarithmic decay rate and the logarithmic decay rate at peak temperature were determined. The result of Example 3 is shown in FIG.

Test 4: Remaining erase density difference after 200 times of repeated erasing / printing The dot density was 8 dots / mm, and the applied energy was 0.
Printing with a thermal head of 40 mJ / dot, temperature 1
30 linear velocity at ℃ by using the printer to erase a heat roller of 33 mm / sec 2 and erase printing 1 cm ² images
This was repeated 00 times, and the background density and the density of the 1 cm ² image area after erasing were measured with a Macbeth densitometer RD914, and the density difference between the erased area and the background was erased to obtain a remaining density difference.

[0086]

[Table 1]

From the above results, in Examples 1 to 6, since the values indicating the dynamic friction coefficient, the glossiness, and the coating film strength were all within the specified values, the residual erase density difference after 200 times of repeated erasure / printing was low. It can be seen that unerased parts are hardly generated. On the other hand, in Comparative Examples 1 to 3, since some of the values indicating the dynamic friction coefficient, the glossiness, and the heat resistance are out of the specified values, the density difference remaining after erasing is increased, and it can be seen that residual erasing occurs. In Comparative Example 4, the coating film strength was weak, printing was impossible, and measurement was impossible.

[0088]

As described above, the reversible thermal recording medium of the present invention is an excellent one having high practicability, which is hardly left unerased even after repeated use.

[Brief description of the drawings]

FIG. 1 is a diagram showing color development / decoloration characteristics of a reversible thermosensitive recording medium of the present invention.

FIG. 2 is a diagram illustrating a layer configuration example of a reversible thermosensitive recording medium of the present invention.

FIG. 3 is a diagram showing an example of a reversible thermosensitive recording medium of the present invention.

FIG. 4 is a diagram showing another example of the reversible thermosensitive recording medium of the present invention.

FIG. 5 is a diagram showing an example of use of the reversible thermosensitive recording medium of the present invention.

FIG. 6 is a diagram showing an example of a reversible thermosensitive recording device of the present invention.

FIG. 7 is a diagram showing another example of the reversible thermosensitive recording apparatus of the present invention.

FIG. 8 is a diagram showing another example of the reversible thermosensitive recording apparatus of the present invention.

FIG. 9 is a diagram showing an example of an energization control unit in the reversible thermosensitive recording apparatus of the present invention.

FIG. 10 is a diagram showing another example of the power supply control means in the reversible thermosensitive recording apparatus of the present invention.

FIG. 11 is a diagram showing a power supply circuit of an energization control unit in the reversible thermosensitive recording apparatus of the present invention.

FIG. 12 is a diagram showing a state of an energizing pulse and a temperature change of a thermal head in the present invention.

FIG. 13 is a diagram showing processing contents of an energizing pulse in the present invention.

FIG. 14 is a diagram conceptually showing melting points, glass transition points, and strengths of various resins.

FIG. 15 is a table showing the aggregation energy and molecular volume of each group and site constituting the resin material.

FIG. 16 is a table showing the aggregation energy of each polymer material.

FIG. 17 is a graph showing a general vibration cycle and a logarithmic decay rate of an aqueous emulsion resin.

FIG. 18 is a graph showing a relationship between a logarithmic decay peak temperature and a logarithmic decay rate of a cured resin coating film.

FIG. 19 is a diagram showing a measurement chart in Example 3.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Reversible thermosensitive recording medium 11 Support 13 Reversible thermosensitive recording layer 14 Protective layer 15 Back layer 16 Magnetic recording layer 17 Rewriting recording part 18 Sheet 19 Print display part 20 Magnetic recording part 23 Depression part for IC chip 231 Wafer 232 Wafer Substrate 233 Integrated circuit 234 Contact terminal 235 CPU 236 ROM 237 RAM 238 Input / output interface 239a to 239g Storage area 30 Doorway 31 Transport roller 32 Guide roller 33 Sensor 34 Magnetic head 34C Control means 35 Platen roller 36 Guide roller 37 Transport roller 38 Ceramic heater 38a Temperature sensor 38C Ceramic heater control means 39 Guide roller 40 Transport roller 43 Sensor 44 Platen roller 45 Transport roller 46 Transport roller 47 Transport roller 48 Transport bell G 49b Transport path 50 Transport path 51 Sensor 52 Platen roller 53 Thermal head 53a Temperature sensor 53C Thermal head control means 55a Transport path switching means 55b Transport path switching means 56a Transport path 56b Transport path 57a Limit switch 57b Limit switch 58 Transport belt 59 Transport Roller 60 Guide roller 61 Exit 70 Insertion opening 71 Reversible thermosensitive recording medium 72 First transport path 73 Transport belt 74 Guide roller 75 Control means 76 Magnetic head 77 Platen roller 78 Transport belt 79 First sensor 80 Control means 81 Second sensor 82 Control means 84 Transport path switching means 85 First transport path 86 Transport belt 87 Control means 88 Thermal head 89 Platen roller 90 Transport belt 91 Exit 92 Second transport path 93 Limit switch 4 Conveying belt TR1 Transistor TR2 Transistor TR11 Transistor TR12 Transistor L11 Primary coil L21 Secondary coil R1 Resistance R3 Resistance R11 Resistance Rx Resistance SM1 Thermistor C1 Capacitor D Rectifier SW Switch 103 Current adjustment means 104 Input means 105 Judgment / comparison means 106 Judgment / comparison means 107 Rewriting device control means 108 Timer input means 109 Data memory 110 Controller 111 Memory CR1 Ceramic heater relay CR2 Thermal head relay 113a Switch 113b Switch 114 Thermo volume 115 Resistance 116 Resistance 117 Comparator 118 Resistance 123 Comparator 125 Microcomputer 126 AC power supply 129 Capacitor 130 Timer control cycle VD power terminal AΦ input port BΦ Input Port CΦ input port DΦ output port EΦ output port 141 ROM (read only memory 143 register 144 data latch unit 145 N pulse counter 146 energizing time creating counter unit 147 driver

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) B42D 15/10 521 B41J 3/20 109E G06K 19/06 B41M 5/18 B H 101A 101E G06K 19/00 B (72) Inventor Hiromi Furuya 1-3-6 Nakamagome, Ota-ku, Tokyo F-term in Ricoh Co., Ltd. (reference) 2C005 HA10 HB04 HB14 JA02 JA03 JA26 JC02 KA15 KA27 KA40 MA11 MB02 NA02 2H026 AA07 AA09 BB02 BB24 DD07 DD32 DD43 DD45 DD48 DD55 EE03 EE05 FF01 FF11 FF25 GG01 GG03 5B035 AA07 BA03 BA05 BB01 BB02 BB03 BB09 CA01 CA08

Claims (19)

[Claims] 1. A reversible sensor which can form a relatively colored state by using a heating temperature and / or a cooling rate after heating using an electron-donating color-forming compound and an electron-accepting compound on a support. In a reversible thermosensitive recording layer containing a thermal composition and a reversible thermosensitive recording medium comprising a protective layer provided on the reversible thermosensitive recording layer, the dynamic friction coefficient of the surface of the protective layer is 0.2 or less, and The surface glossiness is 40% or less, the peak temperature of the viscoelastic logarithmic decay rate measured by the rigid pendulum automatic damping vibration method is 100 ° C. or more, and the logarithmic decay rate at the peak temperature is 0.3 or less. Characteristic reversible thermosensitive recording medium. 2. A reversible material that can form a relatively colored state by using an electron-donating color-forming compound and an electron-accepting compound on a support and changing the heating temperature and / or the cooling rate after heating. In a reversible thermosensitive recording layer containing a thermal composition and a reversible thermosensitive recording medium comprising a protective layer provided on the reversible thermosensitive recording layer, the dynamic friction coefficient of the surface of the protective layer is 0.2 or less, and The surface glossiness is 40% or less, the peak temperature of the viscoelastic logarithmic decay rate measured by the rigid pendulum automatic damping vibration method is 150 ° C. or more, and the logarithmic decay rate at the peak temperature is 0.6 or less. Characteristic reversible thermosensitive recording medium. 3. A reversible sensor which can form a relatively colored state by using an electron-donating color-forming compound and an electron-accepting compound on a support and changing a heating temperature and / or a cooling rate after heating. In a reversible thermosensitive recording layer containing a thermal composition, and a reversible thermosensitive recording medium comprising a protective layer provided on the reversible thermosensitive recording layer, the protective layer contains silica particles coated or complexed with calcium. A reversible thermosensitive recording medium characterized by containing. 4. The reversible thermosensitive recording medium according to claim 1, wherein the protective layer is the protective layer according to claim 3. 5. An average particle size of the silica particles coated or complexed with calcium is 0.3 to 3.0 μm.
m.
4. The reversible thermosensitive recording medium according to item 1. 6. The composition according to claim 1, wherein the content of the silica particles coated or complexed with calcium is 5 to 50 parts by weight based on 100 parts by weight of the protective layer resin in terms of solid content. 5. The reversible thermosensitive recording medium according to any one of 5. 7. The reversible thermosensitive recording medium according to claim 1, wherein a resin in which a silicone segment is bonded in a block shape or a graft shape is used in the protective layer. 8. The resin in which the silicone segments are bonded in a block or graft form in a cross-linked state by a curing agent, and the curing agent for curing the resin is an isocyanate-based curing agent. Item 8. A reversible thermosensitive recording medium according to any one of Items 1 to 7. 9. The method according to claim 1, wherein the binder resin used in the protective layer is in a cross-linked state by a curing agent, and the curing agent for curing the resin is an isocyanate curing agent. 2. The reversible thermosensitive recording medium according to claim 1. 10. The reversible thermosensitive recording medium according to claim 1, comprising a thermoreversible recording section and an information storage section. 11. The information storage unit according to claim 10, wherein the information storage unit is at least one of a magnetic recording layer, a magnetic stripe, an IC memory, and an optical memory, and is provided in a part of a medium. Reversible thermosensitive recording medium. 12. The reversible thermosensitive recording medium according to claim 1, wherein a support on which two or more types of sheets are bonded is used. 13. The reversible thermosensitive recording medium according to claim 1, wherein the medium is processed into a card shape or a sheet shape. 14. The reversible thermosensitive recording medium according to claim 1, wherein the medium is used in the form of a roll. 15. The reversible thermosensitive recording medium according to claim 1, further comprising a printed portion. 16. A printing / erasing apparatus using the reversible thermosensitive recording medium according to claim 1, wherein the image is formed and / or erased by heating. 17. The erasing apparatus for a reversible thermosensitive recording medium according to claim 16, wherein the color is erased by heating to a temperature lower than the color development start temperature. 18. The erasing device according to claim 16, wherein the heating portion of the erasing device is a heater selected from a thermal head, a ceramic heater, a planar heater, and a heat roller. 19. The printing apparatus according to claim 16, wherein the heating portion of the printing apparatus is a thermal head.