JPH086061B2 - Writing ink for reversible thermosensitive recording sheet and method for erasing the same - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a writing ink which can be used for correction, addition, etc. of the contents printed on a reversible thermosensitive recording sheet, and a method for erasing the ink.

[0002]

2. Description of the Related Art In recent years, there has been a strong demand for the reuse of paper due to the rapid increase in municipal waste and the problem of global environmental protection. However, thermal recording paper is not compatible with word processors and facsimiles.
Despite being widely used in equipment A, it cannot be used as recycled paper for technical and economic reasons, and it is actually discarded. As a method for coping with such a situation, a reversible heat-sensitive recording material capable of heat-sensitive printing capable of repeatedly performing image formation and its erasing has been developed. However, the reversible heat-sensitive recording sheet using the current reversible heat-sensitive recording material cannot be corrected or added with a normal pen on the printed surface due to the property of being repeatedly used. That is, the reversible thermosensitive recording sheet itself can be used many times by repeating printing and erasing, but the characters and figures due to corrections and additions remain without being erased, and the reversible thermosensitive recording sheet is repeatedly used. The usability of will be impaired.

[0003]

A reversible thermosensitive recording material capable of repeatedly forming and erasing an image, wherein the image is formed by thermal printing, and the formed image can be fixed. Has been disclosed in Japanese Patent Laid-Open No. 63-39
377, JP 63-41186, JP 2-566, JP 2-1363, JP 2-80289, JP 2-81672, JP 2-86491. Publication, JP-A-58
-191190, JP 60-193691, JP 60-
255482, Japanese Patent Laid-Open No. 4-14482, International Publication WO 90
/ 11898, JP-A-4-46986, JP-A-4-50289, JP-A-4-50290, JP-A-5-92661 and the like. However, these materials
Since neither correction nor addition by writing is taken into consideration, neither of them has the problems as described above.

SUMMARY OF THE INVENTION An object of the present invention is to solve the problems of the above-mentioned prior art, to enable correction and addition by writing, and also to erase by heating, and a reversible thermosensitive recording sheet ink for writing. It is to provide an erasing method.

[0005]

The above-mentioned object is to provide a writing ink for use in a reversible thermosensitive recording sheet comprising a reversible thermosensitive recording layer provided on a support and an overcoat layer provided on the thermosensitive recording layer. The ink contains a solvent, a thermoplastic organic polymer soluble in the solvent, a dye or a pigment, and the ink solid has a softening or melting temperature of 60 ° C.
To be a writing ink used for a reversible thermosensitive recording sheet characterized by being an ink of not less than 200 ° C., and erasing writings on the reversible thermosensitive recording sheet formed by using the above-mentioned writing ink The method is a reversible method characterized in that the solid content of the ink on the overcoat layer of the reversible thermosensitive recording sheet is softened or melted by heating and is removed from the overcoat layer by transfer or scraping with a roll. This can be achieved by a method of erasing the writing ink used for the heat-sensitive recording sheet.

[0006] The above conclusion is the result of intensive studies by the present inventors in order to solve the above problems. As an ink, a solvent and a thermoplastic organic solvent soluble in the solvent are used. An ink containing a polymer and a dye or a pigment is used, and as a method of erasing writings such as written characters and drawings using the ink, the solid ink content on a reversible thermosensitive recording sheet is heated. It has been found that this can be achieved by a method of removing by softening or melting.

[0007]

When the reversible thermosensitive recording sheet is thermosensitively recorded and is to be corrected or added by writing, it is desirable that the written matter such as characters and figures can be completely removed later. This is because the reversible thermosensitive recording sheet is used repeatedly, and when the reversible thermosensitive recording sheet is subjected to thermosensitive printing, and when it is corrected or added by writing on it, it is used repeatedly. In addition, it is necessary to erase the heat-sensitive printed characters and further erase the characters such as characters and figures that have been corrected or added. If this writing remains, it will impair usability. In addition, even if it is possible to make this handwriting transparent or white by some means or the same color as the background of the reversible thermosensitive recording sheet to make it inconspicuous,
When the components of the writing material remain on the reversible thermosensitive recording sheet, the writing components adhere to the thermal head of the thermal printer during the next thermal printing or cause the generation of dust, or This is also not practical because it causes a problem that the part where the component remains does not develop color or the color density becomes low. For this reason, when the reversible thermosensitive recording sheet is subjected to thermosensitive printing and is to be corrected or added by writing, a method of completely removing the components of the written matter must be used.

The writing ink of the present invention and the method of erasing the same satisfy the above requirements, and the operation thereof will be described in some detail below. First, the features of the ink of the present invention are:
This is because a thermoplastic organic polymer that can be dissolved in a solvent is used. That is, since it is thermoplastic, it softens or melts when heated, and the adhesiveness decreases when it softens or melts, so that it can be relatively easily removed from the reversible thermosensitive recording sheet. Moreover, since it softens and melts and develops wettability, if an object that is easier to adhere to than a reversible thermosensitive recording sheet is brought into contact with it, the solid ink content will shift to the one that is more easily adhered. The solid content of the ink can be easily removed from the reversible thermosensitive recording sheet by the method described above. Such a difference in adhesiveness can be easily achieved by providing an appropriate overcoat layer on the printed surface of the reversible thermosensitive recording sheet. It should be noted that such properties do not change even when a pigment or a dye is added and contained in the ink for visualization. Further, since the thermoplastic organic polymer is soluble in water and other organic solvents, it can be easily made into an ink. When a thermoplastic organic polymer of a type in which a silicone resin is copolymerized or a silicone-modified one is used, the adhesiveness and releasability are well balanced. Good removal of objects can be achieved. In addition, the softening temperature or melting temperature range of the ink solid content is 60 ° C or higher and 200 ° C or lower in consideration of not softening or melting at room temperature and not too high on the contrary in handling during operation. Is desirable.

On the other hand, as a method of removing the ink solid content of a writing using the above ink from the reversible thermosensitive recording sheet, a method utilizing the property of the ink solid content may be used. That is, an erasing device having a heated portion capable of softening or melting the ink solid content and a portion transferring or scraping the softened or melted ink solid content may be used. In particular, the transfer method is a better method than the scraping method because it does not scratch and damage the reversible thermosensitive recording sheet. Further, when the reversible thermosensitive recording sheet to be used is of a type that erases printed characters by heating, there is also an advantage that the printed characters can be erased simultaneously by heating for softening or melting the ink solid content.

Further, the reversible thermosensitive recording sheet which can be used in the present invention is capable of repeatedly forming and erasing an image, and the image is formed by thermal printing, and the formed image is fixed. Any reversible thermosensitive recording sheet capable of erasing this image can be used,
The reversible thermosensitive recording sheets described in the above-mentioned prior art documents such as JP-A-63-39377 to JP-A-5-92661 can be used. It should be noted that these are merely examples that can be used in the present invention, and the scope of the present invention is not limited to these.

[0011]

EXAMPLES The structure of the present invention will be described in detail below with reference to examples. It should be noted that "parts" in the description of this embodiment indicate parts by weight.

[0012]

Example 1 Ink pigment (phthalocyanine blue B) 0.1 part Urethane silicone copolymer resin (SP-2105 manufactured by Dainichi Seika Kogyo Co., Ltd.) 10.0 parts Xylene 300.0 parts Reversible thermosensitive recording Reversible thermosensitive recording on a substrate A reversible thermosensitive recording sheet having a layer and an overcoat layer formed thereon with an ultraviolet curable resin (UK-6034 manufactured by Mitsubishi Rayon Co., Ltd.).

The reversible thermosensitive recording sheet was printed by using a thermal printer, and characters were written on the printed surface by using the ink of the above composition and a pen. When this was applied to a heated roll of 140 ° C. and a silicone roll was brought into contact with the writing surface at the same time, the softened ink solid content of the writing character was completely transferred to the silicone roll. Furthermore, when a stainless spatula was applied to the transfer roll onto which the ink solids had been transferred, the ink solids on the silicone roll could be completely removed.

[0014]

[Example 2] Ink pigment (phthalocyanine green) 0.5 part Silicone-modified acrylic resin (SE-653 manufactured by Mitsubishi Rayon Co., Ltd.) 10.0 parts Solvesso # 150 (thinner manufactured by Exxon Chemical Co., Ltd.) 360.0 parts Reversible thermosensitive recording sheet substrate A reversible thermosensitive recording sheet having a reversible thermosensitive recording layer on the top, and an overcoat layer made of polyvinyl alcohol (GH-17 manufactured by Nippon Synthetic Chemical Industry Co., Ltd.) further thereon.

The above reversible thermosensitive recording sheet was printed using a thermal printer, and characters were written on the printed surface by using the ink of the above formulation and a pen. This was placed on a hot roll at 115 ° C., and at the same time when a stainless steel roll was brought into contact with the writing surface, the softened ink solid content of the writing character was completely transferred to the stainless steel roll. Furthermore, when an iron spatula was applied to the stainless steel roll to which the ink solids had been transferred, the ink solids on the stainless steel rolls could be completely removed.

[0016]

[Example 3] Ink dye (Naphthol Green B) 0.5 part Polyvinyl alcohol (NL-05 manufactured by Nippon Synthetic Chemical Industry Co., Ltd.) 10.0 parts Water 250.0 parts Reversible thermosensitive recording sheet There is a reversible thermosensitive recording layer on the substrate. , And a reversible thermosensitive recording sheet provided with an overcoat layer of polyester resin (Voyron-200 manufactured by Toyobo Co., Ltd.) on the reversible thermosensitive recording sheet, which is printed using a thermal printer, and is printed on the printed surface. A letter was written using the ink of the formulation and the pen. This was placed on a hot roll at 130 ° C., and at the same time, a stainless spatula was brought into contact with the writing surface, and the ink solid content of the above-mentioned written letters could be completely removed.

[0017]

As described above, the writing ink used for the reversible thermosensitive recording sheet and the method for erasing the writing ink have the prior art by using the writing ink having the constitution of the present invention and the erasing method. Solving the problem, you can correct and add by writing, and erase by heating,
It was possible to provide an ink for writing a reversible thermosensitive recording sheet and a method for erasing the ink.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Daiji Sugiuchi 3819 Noborito, Tama-ku, Kawasaki-shi, Kanagawa Sliontec Co., Ltd. (72) Inventor Rinko Takayama 3819, Noboto, Tama-ku, Kawasaki, Kanagawa (72) ) Inventor Kazuyoshi Yatsuka 3819 Noborito, Tama-ku, Kawasaki City, Kanagawa Prefecture Sliontech Co., Ltd.

Claims (4)

[Claims] 1. A writing ink for use in a reversible thermosensitive recording sheet comprising a reversible thermosensitive recording layer provided on a support and an overcoat layer provided on the thermosensitive recording layer, wherein the ink comprises a solvent and a solvent. Used for a reversible thermosensitive recording sheet characterized by being an ink containing a soluble thermoplastic organic polymer and a dye or pigment, and having a softening temperature or melting temperature of the ink solid content of 60 ° C. or higher and 200 ° C. or lower. Writing ink. 2. A method for erasing a writing on a reversible thermosensitive recording sheet formed by using the writing ink according to claim 1, wherein the solid content of the ink on the overcoat layer of the reversible thermosensitive recording sheet is heated. A method for erasing a writing ink used for a reversible thermosensitive recording sheet, characterized in that it is softened or melted by means of a method of removing it from the overcoat layer by transfer with a roll or scraping. 3. A method for erasing a writing ink, which is performed by transferring a writing material on the overcoat layer according to claim 2 with a roll of solid content softened or melted by heating, to obtain the overcoat layer and the ink solid. The solid content of the ink is transferred from the overcoat layer to the roll, and the solid content of the ink transferred to the roll is used by utilizing the difference between the adhesiveness between the ink and the ink and the adhesiveness between the ink and the roll. A method for erasing a writing ink used for a reversible thermosensitive recording sheet, characterized in that it is a method of scraping off with a spatula. 4. The thermoplastic organic polymer component of the above-mentioned writing ink is a polymer substance obtained by copolymerizing a silicone resin or a silicone-modified polymer substance. A writing ink for use in the reversible thermosensitive recording sheet according to Crab.