JP3371213B2 - Image erasing method for reversible thermosensitive recording display - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for erasing an image on a reversible thermosensitive recording display, and more particularly to a reversible thermosensitive recording medium for enabling the reversible thermosensitive recording display to be repeatedly used many times without inconvenience. Method for erasing image on record display and image
Regarding the erasing device .

[0002]

2. Description of the Related Art In recent years, temporary image formation (recording) can be performed and the image can be erased when it is no longer needed.
Moreover, reversible thermosensitive recording materials capable of repeating recording and erasing have been receiving attention. As a typical example thereof, a reversible thermosensitive recording material in which an organic low molecular weight substance such as a higher fatty acid is dispersed in a resin base material such as a vinyl chloride resin is known (JP-A-55-154198). Gazette).
The reversible heat-sensitive recording material is also used as a display unit for IC cards, magnetic cards, tip cards, etc.
Furthermore, it is also applied to various displays, display units such as facsimiles.

However, in the above cards, it is general that a new image is formed after an image (including print) on the display unit is once erased each time new recording or storage is performed in the storage unit. Target. The erasing of an image in the reversible thermosensitive recording material is generally performed by a heating method such as a heat stamp, a heat roll, a contact type heat block and a non-contact type heat block. In some cases, wrinkles and the like sometimes occur, which eventually hinders the transport of the reversible thermosensitive recording material, and the display image cannot be formed smoothly. Seen.

[0004]

SUMMARY OF THE INVENTION The object of the present invention is to provide a reversible thermosensitive recording display which is good and has a good quality for a long period of time without causing the above-mentioned inconvenient situations (especially curling and wrinkling). A method of erasing an image of the display body and an image erasing apparatus that maintain

[0005]

DISCLOSURE OF THE INVENTION According to the present invention, a reversible thermosensitive recording medium having a heat-sensitive layer capable of forming and erasing an image depending on temperature on a support is heated to erase the image. a method of performing pressurized for image erasing in the display body
Immediately after the heat treatment, the display body temperature is cooled to room temperature.
It is characterized in that the curvature processing is performed in the process. Also,
The present invention relates to a device for erasing an image by heating a reversible thermosensitive recording medium having a thermosensitive layer capable of forming and erasing an image on a support depending on the temperature. Means for performing heat treatment for image erasing, and the table
It is characterized by comprising a means for performing a curvature process until the body temperature is cooled to room temperature . This is intended to counteract the tendency to bend to the one side by heating and the tendency to bend to the opposite side.

[0006] Te method and apparatus odor of the present invention, before Symbol of
When the heat treatment for erasing the image is performed by non-contact heating, the gap between the reversible thermosensitive recording medium and the display is 20 times or less the thickness of the display (preferably 2 to 20).
Heat treatment through a heating element that is
It is also effective to provide a curvature until the display body temperature is cooled to room temperature.

The present invention will be described in more detail below. In the present invention, the “thermosensitive layer capable of forming an image and erasing the image depending on the temperature” may be any as long as the transparency and the color tone are reversibly changed by heat. For example, two or more polymers are mixed. , Those which change to transparent or white turbid due to the difference in their compatibility (JP-A-61-258853) and those which utilize the phase change of a liquid crystal polymer (JP-A-62-669).
No. 90), the state of the first color is at a first specific temperature higher than room temperature, the state of the second color is by heating at a second specific temperature higher than the first specific temperature, and then cooling. And the like.

In particular, the one whose color state changes at the first specific temperature and the second specific temperature is preferably used. As an example of these, a transparent state is obtained at a first specific temperature and a cloudy state is obtained at a second specific temperature (Japanese Patent Laid-Open No. 55-1541).
98), a color that develops at a second specific temperature and a color that disappears at a first specific temperature (Japanese Patent Application No. 2-414438), a white turbid state at the first specific temperature, and a second specific temperature. Which becomes a transparent state (Japanese Patent Laid-Open No. 3-169590), one which develops black, red, blue or the like at a first specific temperature and is erased at a second specific temperature (Japanese Patent Laid-Open No. 2-188293).
JP-A No. 2-188294).

Among these, those in which an organic low molecular weight substance is dispersed in a resin and which are in a transparent state at a first specific temperature and become a cloudy state in a second specific state are preferably used in terms of sensitivity and durability. (JP-A-63-39378, JP-A-63-130380, JP-A-2-1363, JP-A-64-14079, JP-A-3-7377, JP-A-63-221087, JP-A-63-221087, JP-A-63-221087, Sho 63-317385
JP-A No. 2-566, JP-A No. 4-85077, JP-A No. 1-138781, JP-A No. 2-3876, and JP-A No. 3-130188.
54, Japanese Patent Application No. 1-140109, etc.).

A protective layer may be provided on the heat-sensitive layer to protect the heat-sensitive layer. Protective layer (thickness 0.
(1 to 5 μm), silicone rubber, silicone resin (JP-A-63-221087), polysiloxane graft polymer (Japanese Patent Application No. 62-15255).
No. 0), an ultraviolet curable resin or an electron beam curable resin (described in Japanese Patent Application No. 63-310600). In any case, a solvent is used at the time of coating, but it is desirable that the solvent is difficult to dissolve the resin of the heat sensitive layer and the organic low molecular weight substance. Examples of the solvent that hardly dissolves the resin and the organic low molecular weight substance in the heat-sensitive layer include n-hexane, methyl alcohol, ethyl alcohol, isopropyl alcohol and the like, and the alcohol solvent is particularly preferable from the viewpoint of cost.

Furthermore, an intermediate layer may be provided between the protective layer and the heat-sensitive layer in order to protect the heat-sensitive layer from the solvent and monomer components of the protective layer-forming liquid. As the material for the intermediate layer, the following thermosetting resins and thermoplastic resins can be used in addition to those listed as the resin base material in the heat sensitive layer.
That is, polyethylene, polypropylene, polystyrene,
Examples thereof include polyvinyl alcohol, polyvinyl butyral, polyurethane, saturated polyester, unsaturated polyester, epoxy resin, phenol resin, polycarbonate and polyamide. The thickness of the intermediate layer is preferably about 0.1 to 2 μm.

When a transparent support is used as the support, a plastic film of the same material is used,
The light transmittance is preferably 50% or more, more preferably 70% or more, and particularly preferably 80% or more.

The support and the thermosensitive layer may be in direct contact with each other, but if they are provided with an adhesive layer interposed, a reversible thermosensitive recording display having adhesive strength can be obtained.
Examples of the adhesive layer include general polyester, polyurethane, polystyrene, epoxy resin, polyamide, polyvinyl alcohol and the like.

Further, in the reversible thermosensitive recording display of the present invention, by providing a magnetic layer, a part of magnetically recorded information can be displayed on the thermosensitive layer. Improves convenience. The magnetic layer is provided on the support opposite to the heat-sensitive layer or between the colored layer and the support.
The magnetic layer can also serve as the coloring layer. In addition to the magnetic layer, an information storage unit such as an IC, an optical memory, and a magneto-optical memory may be provided, and a part of the stored information may be displayed on the heat sensitive layer as needed.

The magnetic layer is formed by depositing a magnetic material on a support by a method such as vacuum evaporation or sputtering, or
It can be formed by applying a magnetic material together with a resin binder and drying. As a magnetic material,
Iron, cobalt, etc., and their alloys or compounds are mentioned. Examples of the resin binder include various thermoplastic resins, thermosetting resins, ultraviolet curable resins, and electron beam curable resins.

If desired, a colored layer may be provided,
In that case, a method such as vacuum deposition or sputtering,
It can be colored with Al, Au, or the like, or can be colored with a pigment, a dye, or the like and the same series of binders as described above.
A smooth layer is provided depending on the unevenness of the support. Advantageously, the smoothing layer also uses the same series of binders as described above. Also, due to the reason that the transparent support is used, the entire surface and the partial bonding are performed (Japanese Patent Laid-Open No. 4-220400, 1-16
No. 5286), various colored designs are provided on the base, and the same magnetic, IC, optical memory,
It is also possible to provide a magneto-optical memory.

These reversible thermosensitive recording mediums, when an image is erased by a hot stamp, as shown in FIG. 1, (a) the surface of the hot stamp 2 (the presence of the reversible thermosensitive display medium is present). If R is provided on the side surface) and the reversible thermosensitive recording display 1 is sandwiched between the hot stamp 2 and the pressing tool 4, curling of the reversible thermosensitive recording display 1 can be suppressed. As shown in FIG. 1B, it is also effective to sandwich the reversible thermosensitive recording display body 1 between two heating bodies 2 and 2 '. In the means shown in FIGS. 1A and 1B, it is needless to say that sufficient care must be taken so that the IC, optical memory, magneto-optical memory, etc. are not affected by heating or pressurization. This also applies to the means illustrated below.

As shown in FIG. 2, the reversible thermosensitive recording medium 1 is curled when the heat block 2 "is heated by contact or non-contact with the guide 3 provided with R immediately. Reversible heat-sensitive recording display 1'of both thin type and laminated thin type (both 300
In the image erasing method with a gap, as shown in FIG. 3, when the heating is controlled with a gap of 20 times or less, wrinkles are less likely to occur. Although this thin type reversible thermosensitive recording medium 1'is effective in preventing curling only by passing through the device shown in FIG.
If this is further moved along with the guide 3 shown in FIG. 2, it is more effective in preventing curling. It should be noted that if there is a gap as in the device shown in FIG. 3, it is advantageous because there are no scratches and scratches. However, since the reversible thermosensitive recording medium 1'is thin, the film or the like may be softened by heat and pulled by the front and rear rolls to cause wrinkles. However, a small gap can be recovered with an exit roll.

The heating temperature of the hot stamp 2, the heating element 2 ', the heat block 2 ", the heaters 21 and 22, the degree of R of the hot stamp 2 and the guide 3, and the degree of pressurization are reversible thermosensitive recording display. It cannot be uniformly decided because it depends on the thickness and constitution of the body.

[0020]

EXAMPLES Next, the present invention will be described more specifically with reference to examples. Parts herein are by weight.

Example 1(Reference example) The support is a transparent PET of about 188 μm thick (manufactured by Teijin Limited:
Aluminum vapor deposition on HL7) to a thickness of approximately 6000Å
Then, a light reflection layer was provided. Polyvinyl alcohol on this
(Denka Co., Ltd .: 1000 p) was added to tetrahydrofuran (T
HF) is applied and dried to a thickness of about 0.5 μm.
A PVA layer was provided. On top of this,   Lignoceric acid 5 parts   Eicosane diacid 5 parts   39 parts of vinyl chloride-vinyl acetate copolymer (Denka: 100 MT)   THF 100 parts   Toluene 65 parts Of 10 μm thick heat-sensitive layer
Was set up. Furthermore, on this,   75% acetic acid of urethane acrylate UV curable resin       Butyl solution (manufactured by Dainippon Ink and Chemicals: C7-157) 10 parts   Isopropyl alcohol 10 parts Coating solution and drying to form a protective layer of about 4 μm thick
Provided. Then on the transparent PET on the opposite side of the support   γ-Fe₂O₃                                              10 copies   Vinyl chloride-vinyl acetate-vinyl alcohol copolymer 10 parts       (UCC: VAGH)   Isocyanate 2 parts       (Nippon Polyurethane Co., Ltd .: Coronate 50% toluene solution)   Methyl ethyl ketone 40 parts   40 parts of toluene About 9μm thick by applying a liquid consisting of
Magnetic recording layer was provided. Furthermore, on this   Al₂O₃                                                  10 copies   Vinyl chloride-vinyl acetate-vinyl alcohol copolymer 10 parts       (UCC: VAGH)   Isocyanate 2 parts       (Nippon Polyurethane Co .: Coronate L, 50% toluene solution)   Dispersant 0.1 part   Methyl ethyl ketone 70 parts   70 parts of toluene Applied with a wire bar and dried to a thickness of 1 μm
A silver layer was provided to make a reversible thermosensitive recording medium.
This is the hot stamp (curvature: radius shown in Fig. 1 (a).
300 mm) erasing device (approx.
(Tan rubber is provided) 95 ° C / 2sec, 1kg /
cm²Image is erased under the conditions of
Print it out and repeat it 50 times.
The curl amount (1) as shown in 4 is about 2 mm or less
It was The curl amount (l) is 8.5 cm × 5.5 cm.
Either left or right when a sample of a size is left standing on a flat plate
It is expressed by the distance between the curled end and the flat plate surface.
Is the same (hereinafter the same).

COMPARATIVE EXAMPLE 1 The same reversible thermosensitive recording medium as in Example 1 was used, using a hot stamp image erasing apparatus as shown in FIG. 5 (4 'is a flat plate pressing tool) at 95.degree. / 2sec, 1kg
When the image was erased under the condition of / cm ² , printing was performed with the thermal head and this process was repeated, the curl was about 6 mm.
Became.

Example 2 The same reversible thermosensitive recording medium as in Example 1 was applied to an image erasing device of a Teflon-coated heat block 2 ″ shown in FIG. 2 at 95 ° C., 0.4 μm / sec, 0.4 kg / cm.
After erasing under the condition of ² , while the reversible thermosensitive recording medium was cooled from 95 ° C. to 40 ° C., it was passed through an aluminum plate guide 3 (length 50 cm, thickness 2 mm) with a radius of 150 cm and cooled while bending. However, the curl became about 2 mm or less.

Example 3(Reference example) A protective layer (about 4 μm thick) similar to that of Example 1, a heat-sensitive layer
(Approximately 10 μm thickness) Transparent polyethylene sheet as a support
Toyobo (Toyobo A2300, about 50 μm thick)
Was provided with a dark blue colored layer (about 0.1 μm thick). White PET
Adhesive (Toyobo Co., Ltd .: greaser, thickness about 100 μm)
Reversible thermosensitive recording display with a thickness of about 164 μm when bonded with an adhesive
Got Make this a gap of 3mm as shown in Figure 3.
Ceramic heater (width 2mm on both sides), speed
Erase the image under the condition of 0.4 mm / sec, and then
It was printed with a round head and was repeated 50 times.
At that time, no wrinkles were observed.

Example 4 The same reversible thermosensitive recording material as in Example 3 was prepared and heated at 100 ° C. by the apparatus shown in FIG.
If the aluminum guide (length 50 cm, thickness 2 mm) shown in Fig. 2 is bent and pulled while cooling until it cools to 0 ° C, wrinkles will occur even if the image is erased and printed repeatedly 50 times. Also, the curl was about 2 mm or less.

Comparative Example 2 A test was conducted using the same reversible thermosensitive recording material and apparatus as used in Example 3 (however, the gap was 6 mm). As a result, wrinkles were formed and the next printing was inconvenient.

[0027]

According to the first and fifth aspects of the present invention, even when the reversible thermosensitive recording material is repeatedly used, the curl is small, the transportability is good, and the jam does not occur. According to the inventions of claims 2 and 6 , image erasing of the reversible thermosensitive recording medium can be processed at high speed. According to the third, fourth, seventh and eighth aspects of the present invention, curling is prevented particularly when the thin reversible thermosensitive recording display is repeatedly used.

[Brief description of drawings]

1 (a) and 1 (b) are schematic illustrations of two devices useful for carrying out the method of the present invention.

FIG. 2 is a schematic diagram of another apparatus useful for carrying out the method of the present invention.

FIG. 3 is a schematic view of still another apparatus useful for carrying out the method of the present invention.

FIG. 4 is a diagram for explaining a curl amount.

FIG. 5 is a diagram of an example of a device for comparison.

[Explanation of symbols]

1,1 'Reversible thermosensitive recording display 2 hot stamp 2 ', 2 "heating element 3 guide plates 4,4 'Pushing tool

Continuation of the front page (56) References JP-A-5-270144 (JP, A) Fukukaihei 3-6942 (JP, U) (58) Fields investigated (Int.Cl. ⁷ , DB name) B41J 2 / 32 B41M 5/26 B41M 5/36

Claims (4)

(57) [Claims] 1. A method for forming an image on a support depending on temperature.
And a reversible thermosensitive recording display with a thermosensitive layer capable of erasing
In a method of erasing an image by applying heat to the body,
Immediately after the heat treatment for erasing the image on the display body,
Curvature processing is performed until the display body temperature is cooled to room temperature.
Of erasing images on a reversible thermosensitive recording display characterized by
Law. 2. The formation and formation of an image on a support depending on the temperature.
And a reversible thermosensitive recording display with a thermosensitive layer capable of erasing
In a method of erasing an image by applying heat to the body,
The gap between the display and the display is 20 times or more the thickness of the display.
Heat treatment for image erasure is performed through the lower heating element.
No, until the display temperature is cooled to room temperature
A reversible thermosensitive recording table characterized by being subjected to a curvature treatment between
Method of erasing display image. 3. The formation and formation of an image on a support depending on the temperature.
And a reversible thermosensitive recording display with a thermosensitive layer capable of erasing
In a device that erases images by heating the body,
Means for performing heat treatment on the display body for image deletion, and
Perform curvature processing until the display temperature is cooled to room temperature.
A reversible thermosensitive recording table comprising means for applying
Image eraser for display. 4. The formation and formation of an image on a support depending on the temperature.
And a reversible thermosensitive recording display with a thermosensitive layer capable of erasing
In a device that erases images by heating the body,
The gap between the display and the display is 20 times or more the thickness of the display.
Heat treatment for image erasure is performed through the lower heating element.
And means for cooling the display body temperature to room temperature.
Reversible characterized by having means for performing curvature processing between
Image erasing device for thermosensitive recording display.