JPH06227182A - Pressure sensitive duplicate sheet for preventing alteration - Google Patents

Abstract

PURPOSE:To form a coloring image not susceptible to erasing under an entry image, and improve an effect of preventing alteration partially providing microcapsules including a coloring agent and a mixture layer containing a developer on the surface through printing, and forming a transfer sheet having self-colorability. CONSTITUTION:The pressure sensitive sheet 1 is provided with a transfer sheet 2 having microcapsules including a foaming agent A on the rear surface of a carrier. On the front surface of another carrier, a receiving sheet 8 is provided, having a developer layer 10 that colors in reaction with the foaming agent A. In this instance, in a part of the surface of the transfer sheet 2, there is contained a microcapsule 6 including another coloring agent B, and developer 7. Herein, there is provided a self-coloring area 5 in which at least one of components is supplied by printing. When an entry 12 is done on the surface of the transfer sheet 2 by a ball-point pen or the like writing utensils, the coloring agent B in the self-coloring area 5 reacts to the developer 7, and thereby a coloring image 15 not susceptible to erasing is formed under the entry 12.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION This invention relates to pressure sensitive copying sheets,
In particular, the present invention relates to a tampering-proof pressure-sensitive copy sheet that enables efficient confirmation work for tampering.

[0002]

2. Description of the Related Art Electron-donating color formers such as crystal violet lactone and benzoyl leuco methylene blue,
A pressure-sensitive copying sheet utilizing a color reaction of an electron-accepting color developer such as activated clay, a phenol-formaldehyde condensate, and a polyvalent metal salt of an aromatic carboxylic acid is well known. Such pressure-sensitive copying sheets are produced by phase separation method, interfacial polymerization method, in-sit
u Top paper (transfer sheet) coated with color-forming agent-encapsulated microcapsules prepared by a method such as polymerization, bottom paper (receptor sheet) coated with color-developing agent on the support, the above-mentioned color-forming agent-encapsulated microcapsules Medium papers (sheets having both the functions of a transfer sheet and a receiving sheet) in which a color developer and a color developer are applied to different surfaces of a support are appropriately combined for practical use. However, while these pressure-sensitive copy sheets are convenient in that they can be easily copied, they can be easily written or erased by using writing instruments, other pressure-sensitive copy sheets of the same color, eraser, correction ink, etc. Since it can be tampered with, there is a problem that various troubles occur depending on the application.

In order to solve such a problem, for example, as shown in FIG. 5, a developer layer 10 is thinly laminated on the color-forming agent-containing microcapsule layer 4 on the back surface of the transfer sheet 2,
There has been proposed a pressure-sensitive copy sheet having a tamper-proof function with a back surface of a self-coloring type. In this copy sheet, images 13 and 14 are formed on the developer layer 10 of the receiving sheet 8 by the writing pressure when writing 12 on the surface of the transfer sheet 2, and at the same time, the developer layer 10 on the back surface of the transfer sheet 2 is formed. Also, the image 15 is formed, and even if the characters written on the front surface of the transfer sheet 2 are erased or rewritten, the image on the back surface remains, so that tampering is not easy. However, in the case of this type of pressure-sensitive copy sheet, since the entry 12 and the image 15 of the transfer sheet 2 are not on the same surface, it takes time to confirm the presence or absence of tampering, which is not suitable for a large amount of confirmation processing. Is.

[0004]

SUMMARY OF THE INVENTION It is a first object of the present invention to provide a tampering-proof pressure-sensitive copy sheet capable of efficiently confirming the presence or absence of tampering.
Further, a second object of the present invention is to provide a transfer sheet which has an excellent tampering prevention function and is free from dirt.

[0005]

As a result of earnest research, the present inventors have found that the above problems can be solved by partially providing a self-coloring region on the surface of a transfer sheet by printing, and completed the present invention. It came to do. That is, the present invention relates to a pressure-sensitive copying sheet in which a transfer sheet having a color-forming agent-encapsulating microcapsule layer on the back surface of a support and a receiving sheet having a developer layer on the surface of the support to develop a color by reacting with the color-forming agent are combined. In addition, tampering prevention, characterized in that a part of the surface of the transfer sheet contains a color-forming agent-encapsulating microcapsule and a color-developing agent, and at least one of the components is provided with a self-color-forming area supplied by printing. This is a pressure-sensitive copying sheet.

[0006]

First, the tamperproof pressure-sensitive copying sheet of the present invention will be described in detail with reference to the drawings. FIG. 1 is a cross-sectional view illustrating a pressure-sensitive copy sheet 1 for tampering prevention according to the present invention. A microcapsule layer 4 containing a color former A on the back surface of the support 3, a microcapsule 6 containing a color former B on the surface, and a mixed layer containing a color developer 7 are partially provided by printing to provide self-coloring property 5. The transfer sheet 2 and the receiving sheet 8 having the developer layer 10 on the entire surface of the support 9 are combined.

In this copy sheet 1, when writing 12 on the surface of the transfer sheet 2 with a ball-point pen 11 or the like, the microcapsules are destroyed by the writing pressure, and the coloring agent A is transferred from the transfer sheet 2 to the developer layer 10 of the receiving sheet 8. Transfer to and copy 1
3,14 are obtained. At the same time, the coloring agent B in the self-coloring area on the surface of the transfer sheet 2 reacts with the developing agent to fill in 1
A colored image 15 is formed under the image 2.

[0008] The transfer sheet 2 after recording has a written image 1 on the surface.
Even if 2 is erased and rewritten by some means, the color image 15 cannot be easily erased, and therefore it is difficult to tamper. In addition, the self-coloring area 5 on the surface of the transfer sheet
Is locally provided by the printing method, so that the stain on the sheet during handling is not noticeable even if the location has a clear color tone.

FIG. 2 shows another embodiment of the present invention.
Partially printing a microcapsule layer 4 containing the color former A on the back surface of the support 3 and a microcapsule layer 16 containing the color former B on a sheet on the entire surface of which the color developer layer 10 is provided. A combination of the transfer sheet 2 which is the self-coloring area 5 and the receiving sheet 8 in which the developer layer 10 is provided on the entire surface of the support 9. The copy sheet having this structure is slightly expensive in price because the developer layer is coated on the entire surface, but has the same excellent function as in FIG.

FIG. 3 shows still another embodiment of the present invention. A microcapsule layer 4 containing a color former A on the back surface of the support 3 and a microcapsule layer 16 containing a color former B on the surface thereof. A transfer sheet 2 in which a color material layer 14 is overprinted to partially form a self-coloring area 5 and a receiving sheet 8 in which a color developer layer 10 is provided on the entire surface of a support 9 are combined. . The copy sheet having this structure is slightly expensive in price because it has one more printing process than that in FIG.
It has the same excellent function as.

FIG. 4 shows still another embodiment of the present invention, in which a micro-coloring agent C having a color tone different from that of the color-developing agent A is included in a part of the back surface of the transfer sheet of FIG. 1 on the capsule layer 4. The capsule layer 17 is provided by printing. This copy sheet can prevent tampering with not only the transfer sheet but also the receiving sheet.

Examples of the color former used in the present invention include the following electron-donating color formers known in the field of pressure-sensitive copying sheets. Triallylmethane compounds such as 3,3-bis (p-dimethylaminophenyl) -6-dimethylaminophthalide and 3,3-bis (1,2-dimethylindol-3-yl) -5-dimethylaminophthalide Dye, 4,4'-bis-dimethylaminobenzhydrylbenzyl ether, N-2,
Diphenylmethane dyes such as 4,5-trichlorophenyl leuco auramine, thiazine dyes such as benzoyl leuco methylene blue, p-nitrobenzoyl leuco methylene blue, spiro such as 3-phenyl-spiro-dinaphthopyran, 3-propyl-spiro-dibenzopyran -Based dyes, lactam-based dyes such as rhodamine-B-anilinolactam, rhodamine (o-chloroanilino) lactam, 3- (N-ethyl-p-toluidino) -7-methylfluorane, 3-piperidino-methyl-7- Fluoran-based dyes such as phenylaminofluorane and mixtures thereof.

When the color-forming agent is microencapsulated, these are usually dissolved in an oily substance and used as a core substance. Examples of the oily substance include those described below in the field of pressure-sensitive copying sheets. Such substances are exemplified.
Vegetable oils such as cottonseed oil, mineral oils such as kerosene, paraffin, naphthene oil and chlorinated paraffin, aromatic carbonization such as alkylated biphenyl, alkylated terphenyl, alkylated naphthalene, diarylethane, triarylmethane and diphenylalkane. Hydrogen, dimethyl phthalate, diethyl phthalate, di-n-butyl phthalate, dioctyl phthalate, diethyl adipate, di-n-propyl adipate, di-n-butyl adipate,
Esters such as dioctyl adipate and mixtures thereof. The blending amount of the color former with respect to the oily substance cannot be unconditionally determined depending on the solubility of the colorant into the oily substance, the color developing ability, etc.
00 parts by weight, more preferably 2 to 100 parts by weight.

The microcapsules used in the present invention are
A conventionally known coacervation method (for example, US Pat. No. 2
No. 8000457, No. 2800458 and the like), interfacial polymerization method (for example, Japanese Examined Patent Publication No. 38-19574).
No. 42, No. 42-446, No. 42-771, No. 49-45133, etc.), in-situ
Polymerization method (for example, Japanese Patent Publication No. 36-9168, Japanese Patent Publication No. 51-
No. 9079 and Japanese Patent Publication No. 53-84881).

The microcapsule layer is formed by printing or coating an aqueous or non-aqueous capsule ink or coating liquid. In the case of an aqueous system, a binder, a capsule protective agent (stilt agent), a surfactant, an antifoaming agent, a pigment, an antiseptic agent, an aqueous capsule dispersion liquid, if necessary.
It is prepared by adding an ultraviolet absorber or the like. On the other hand, in the case of a non-aqueous system, a binder, a capsule protector (stilt agent), a surfactant, a pigment, an ultraviolet absorber, a release agent, a photopolymerization initiator, a sensitizer and Various auxiliaries such as a sensitizer, a wax, a drier, a thickener and a gelling agent are added to prepare an evaporative drying type, an ultraviolet curing type, an oxidative polymerization type and the like. The mixing ratio of each material to the ink or the coating liquid is appropriately determined in consideration of the suitability for printing or coating, the performance of the sheet to be obtained, and the like. It is set in the range of 10 to 50 parts by weight based on 100 parts by weight of the coating liquid.

Examples of the aqueous binder used for preparing the capsule ink or the coating liquid include water-soluble binders and latex binders. As the water-soluble binder, for example, proteins such as gelatin, albumin, casein, cereal starch, pregelatinized starch, oxidized starch, etherified starch, starch such as esterified starch, carboxymethyl cellulose, cellulose such as hydroxyethyl cellulose, Water-soluble natural polymer compounds such as agar, sodium alginate, and polysaccharides such as arabic gum, and water-soluble synthetic polymer compounds such as polyvinyl alcohol, polyvinylpyrrolidone, polyacrylic acid, polyacrylamide, and maleic acid copolymers, and these Examples of the mixture and latex binders include styrene-butadiene latex, acrylonitrile-butadiene latex, and the like.
Examples thereof include acrylic acid ester-based latex, vinyl acetate-based latex, methyl methacrylate-butadiene latex, carboxy-modified (for example, acrylic acid) latex thereof, and a mixture thereof.

An oil-soluble binder can be used as the binder used in the non-aqueous capsule ink or the coating liquid. As the oil-soluble binder, for example, rosin,
(Gum rosin, wood rosin, tall oil rosin), natural resins such as cerax, copearl, dalman, gilsonite, zein, hardened rosin, ester gum and other rosin esters, maleic acid resin, fumaric acid resin, duplex rosin, polymerized rosin, rosin Modified phenol resin, methyl cellulose, ethyl cellulose, hydroxypropyl cellulose, ethyl hydroxyethyl cellulose, cellulose acetate propionate, cellulose acetate butyrate, semi-synthetic resin such as nitrocellulose, phenol resin, xylene resin, urea resin, melamine resin, ketone resin, Coumarone indene resin, petroleum resin,
Terpene resin, cyclized rubber, chlorinated rubber, alkyd resin, polyamide resin, acrylic resin, polyvinyl chloride, vinyl chloride / acetic acid copolymer, polyvinyl acetate, polyvinyl butyral (butyral resin), polyvinyl pyrrolidone, chlorinated polypropylene resin, Examples thereof include synthetic resins such as epoxy resin and polyurethane, and mixtures thereof. These binders are selected according to the type of medium to be used, but as for the method of use, the methods disclosed in, for example, printing ink technology CMC Corp. can be appropriately adopted.

As the non-aqueous medium used when preparing the non-aqueous ink or coating liquid, there are low-boiling medium, high-boiling medium, ethylenically unsaturated compound, oils, waxes and the like known in the printing industry. It can be used as appropriate. Specific examples include benzene, toluene, xylene, cyclohexane,
Hexane, methyl isobutyl ketone, methyl acetate, ethyl acetate, butyl acetate, methanol, ethanol, n-propyl alcohol, isopropyl alcohol, n-butanol, n-hexanol, cyclohexanol, 2-
Ethylhexyl alcohol, ethylene glycol, diethylene glycol, triethylene glycol, polyethylene glycol, propylene glycol, dipropylene glycol, methyl cellosolve, ethyl cellosolve, butyl cellosolve, dienelen glycol monobutyl ether, diethylene glycol monobutyl acetate, ethylene glycol diacrylate, ethylene glycol dimetha Acrylate, polyethylene glycol diacrylate, polyethylene glycol dimethacrylate, propylene glycol diacrylate, propylene glycol dimethacrylate, polypropylene glycol diacrylate, polypropylene glycol dimethacrylate, 1,2-butanediol diacrylate, 1,
2-butanediol dimethacrylate, 1,3-butanediol diacrylate, 1,3-butanediol dimethacrylate, 1,4-butanediol diacrylate, 1,4-butanediol dimethacrylate, 1,6
-Hexanediol diacrylate, 1,6-hexanediol dimethacrylate, neopentyl glycol diacrylate, glycerol dimethacrylate, glycerol methacrylate acrylate, neopentyl glycol diacrylate, trimethylolpropane diacrylate, trimethylolpropane triacrylate,
Pentaerythritol triacrylate, pentaerythritol tetraacrylate, reaction product of epoxy resin and acrylic acid, condensation product of maleic acid and diethylene glycol and acrylic acid, carnauba wax, microcrystalline wax, stearyl alcohol, stearic acid, stearic acid amide, vegetable oil ( Dry oils such as linseed oil and sunflower oil, semi-drying oils such as soybean oil, dehydrated castor oil, polymerized oils, maleated oils, vinylated oils, urethane oils), mineral oils (machine oils, spindle oils) and mixtures thereof. Etc. The amount of the capsule ink or coating liquid applied to the support is not limited to this,
Chromogenic and 1 to 15 g / m ² from the viewpoint of economy, and more preferably from 2 to 10 g / m ^2.

Examples of the color developing agent include the following electron-accepting color developing agents known in the field of pressure-sensitive copying sheets. Clays such as acid clay, activated clay, attapulgite, zeolite, bentonite, phenolic resins, polyvalent metal salts of various aromatic carboxylic acids as described in JP-B-51-25174, JP-A-54-
Organic developer such as zinc salt of 2,2'-bisphenol sulfone compound as described in 106316 and mixtures thereof.

The developer layer is formed by printing or coating an aqueous or non-aqueous developer ink or coating liquid. In the case of an aqueous system, in addition to the developer and binder,
It is prepared by adding a pigment, an oil capsule, an ultraviolet absorber, an antioxidant, a fluorescent dye, a surfactant, a dispersant, an antiseptic, an antifoaming agent, etc., if necessary. In the case of a non-aqueous system, usually, in addition to the color developer and the binder, if necessary, a pigment,
Various auxiliaries such as oil capsules, surfactants, UV absorbers, photopolymerization initiators, sensitizers, waxes, dryers, thickeners, gelling agents are added, and evaporation drying type, UV curing type, oxidative polymerization It is prepared as a mold or the like.

The developer can be used by dissolving or dispersing it in an oily substance and then encapsulating it in microcapsules. The amount of the developer and the binder to be added to the ink or the coating liquid is usually 5 to 90 parts by weight of the developer and 5 to 5 parts by weight of the binder with respect to 100 parts by weight of the ink (coating liquid) (solid content).
0 parts by weight. Further, the coating amount of the color developing ink or the coating liquid on the support is not limited to this, but from the viewpoint of color developability and economical efficiency, it is 0.5 to 15 g / m ² , more preferably 1 to 8 g. / M ² .

Examples of the pigment used for preparing the color developing ink or the coating liquid include silica, colloidal silica, zeolite, bentonite, kaolin, calcined kaolin, calcium phosphate, calcium carbonate, magnesium carbonate, calcium sulfate, aluminum hydroxide, zinc oxide, Inorganic and organic pigments known in the art, such as titanium oxide, melamine resin particles, urea resin particles, and polystyrene resin particles, and mixtures thereof can be mentioned.

As the binder, in the case of an aqueous ink (coating liquid), the above-mentioned water-soluble binder or latex binder is used, and in the case of a non-aqueous ink (coating liquid), the above-mentioned binder. A non-aqueous binder is used. As the medium used when preparing the non-aqueous ink or the coating liquid, the above-mentioned non-aqueous medium is used. A stirrer, a ball mill, a sand grinder, etc. are usually used for preparing the ink or the coating liquid.

In the present invention, the method for forming the self-coloring region 5 on the surface of the transfer sheet is a mixed ink prepared by mixing the color-forming agent-encapsulating microcapsule ink and the color-developing ink (hereinafter referred to as mixed ink). ), A color-encapsulating agent-containing microcapsule ink and a color-developing agent ink are separately printed and laminated, and a color-forming agent-encapsulating microcapsule is formed on the developer layer formed by coating the entire surface with a coating machine. A method of printing an ink, a method of printing a color developer ink on a color-forming agent-encapsulating microcapsule layer formed by coating the entire surface with a coating machine, but among them,
The separate method is particularly preferable in terms of cost and production efficiency.

The mixed ink is usually prepared so that the ratio of the color-forming agent-containing microcapsules to the color-developing agent is in the range of 1:10 to 10: 1. The amount of the mixed ink applied to the support is not particularly limited, but from the viewpoint of color development and economy, it is 1 to 10 g / m ² , more preferably ² to 8 g / m ² .
Adjusted in the range of m ² . Further, as the color developer used in the mixed ink, it is preferable in terms of performance to use the whole amount or a part thereof in the form of microcapsules.

In the present invention, a more preferable embodiment in which the tampering prevention function is further strengthened is one in which the self-coloring region is colored with a decolorizable material. That is, since the self-coloring area is colored with a decolorizable material, even if the color-developed image of the self-coloring area is erased by some means, the tampering is detected because the coloring of the area is erased at the same time. be able to.

The decolorizable material is not particularly limited, but a substance produced by the reaction of the above-mentioned color former and developer is usually used. As a method of coloring the self-coloring area with a material capable of being erased, the ink is used as an ink to erase the color-erasable material, and the ink is printed in, under, or on the layer of the microcapsule layer, the developer layer, or the Cercon layer. You can take the way. Among them, the method of adding the decolorizable colorant to the mixed ink is particularly preferable because it is the simplest and can be manufactured at a low cost. Note that the coloring exhibits the function of the present invention even if it is the same as the coloring color tone, but it is preferable to change the color tone from the viewpoint of easy tampering judgment.

In the present invention, more preferable one is one in which the back surface of the transfer sheet is divided into areas of the color-forming agent-containing microcapsule layer having different color tones. The method of spot-printing the microcapsule ink containing different color formers, the microcapsules containing color formers with different color tones on the layer formed by smearing the microcapsule coating liquid A method of spot-printing the capsule ink may be mentioned. The present invention can also be used in combination with the peelable color developing ink described in Japanese Patent Application No. 63-48099.

The printing or coating in the present invention is
Usually, it is carried out by a printing machine having a printing unit such as offset, letterpress, flexo and gravure, or a coating machine having a coater head such as air knife, bar, blade, lip, curtain, roll and gravure.

[0030]

EXAMPLES In order to further clarify the effects of the present invention, examples will be given below, but the present invention is not limited to these examples. Parts and% in the examples represent parts by weight and% by weight, respectively, unless otherwise specified.

Example 1 [Preparation of red coloring system capsule] 25 parts of 3,3-bis (2-methyl-1-octyl-3-indolyl) phthalide and 100 parts of alkyldiphenylethane (trade name: Hisol SAS-296, It was heated and dissolved in Nippon Petrochemical Co., Ltd.) to obtain an internal phase oil. The pH was adjusted to 6 by adding 20% caustic soda aqueous solution to 200 parts of 3.0% aqueous solution of ethylene-maleic anhydride copolymer (trade name: EMA-31, manufactured by Monsanto).
After emulsifying this internal phase oil in a liquid of 0, the system was heated to 55 ° C.
The temperature was raised to.

Separately, 45% 37% aqueous formaldehyde solution
15 parts of melamine was added to each part and reacted at 60 ° C. for 15 minutes to prepare an aqueous prepolymer solution. This prepolymer aqueous solution was added dropwise to the emulsion, and after stirring, the mixture was heated to 80 ° C. and kept at that temperature for 1 hour, and then pH was adjusted with 0.2N hydrochloric acid.
Was lowered to 3.5 and kept for 3 hours, and then allowed to cool to obtain a capsule dispersion liquid having an average particle diameter of 6.5 μm. Then, this dispersion was filtered, washed with water, and then dried to obtain a powder capsule.

[Preparation of Red Coloring Mixing Ink] Viscosity 150
To 400 parts of 0 cps UV curable resin, 100 parts of the above-mentioned red coloring system capsule and 20 parts of 3,5-di- (tert-butyl) zinc salicylate (developing agent) were added and dispersed to obtain a red coloring mixed ink. .

[Preparation of Transfer Sheet] 105 parts of internal phase oil obtained by heating and dissolving 5 parts of crystal violet lactone in 100 parts of diisopropyl naphthalene was added to aromatic polyisocyanate (trade name: Coronate-L, manufactured by Nippon Polyurethane Co.). Dissolve 15 parts, add this to 600 parts of a 2% aqueous solution of polyvinyl alcohol and emulsify it to obtain an average particle size of 8.0.
After adjusting the thickness to μm, this system was reacted at 80 ° C. for 4 hours to obtain a capsule dispersion liquid. To this dispersion, 50 parts of starch particles and 20 parts of carboxy-modified styrene / butadiene copolymer latex (solid content) were added and diluted to a concentration of 18% to obtain a microcapsule coating liquid. The obtained capsule coating liquid was smeared on a base paper of 40 g / m ^{2 with} an air knife coater so that the solid content was 3.0 g / m ² . Then, the above-mentioned red coloring system mixed ink is letterpress-printed on the base paper surface of the sheet so that the ink amount is 4.5 g / m ² and the printing area is 10 cm × 10 cm square, and UV curing is carried out to obtain a self-coloring area. A transfer sheet having

[Preparation of Receiving Sheet] 65 parts of light calcium carbonate, 20 parts of zinc oxide, a mixture of 3,5-di- (α-methylbenzyl) salicylic acid zinc salt and an α-methylstyrene / styrene copolymer. (Blend ratio 80/20) 15 parts,
Polyvinyl alcohol aqueous solution 5 parts (solid content) and water 30
40 g of a developer coating liquid prepared by adding 20 parts (solid content) of carboxy-modified styrene / butadiene copolymer latex to a dispersion liquid obtained by crushing 0 part by a ball mill for 24 hours.
/ M ² of the base paper was smeared with an air knife coater so that the dry weight was 5 g / m ² to obtain a receiving sheet.

[Evaluation] The transfer sheet and the receiving sheet were superposed as shown in FIG. 1, and after writing with a pencil, the written image on the transfer sheet was erased with an eraser. Was not erased and could not be tampered with. Further, since the written image 12 and the image of the self-coloring region 15 are formed on the same surface, the confirmation can be performed very easily. Further, although the surface of the transfer sheet was of the self-coloring type, stains during handling were not noticeable.

Example 2 [Preparation of red color-forming capsule ink] 100 parts of the red color-forming capsule obtained in the same manner as in Example 1 had a viscosity of 500 cps.
To 400 parts of UV curable resin to obtain a letterpress type capsule ink. [Preparation of Transfer Sheet] On the back surface of the transfer sheet obtained in the same manner as in Example 1, the red color-forming capsule ink was letterpress-printed and UV-cured to obtain a transfer sheet.

[Evaluation] The above transfer sheet and the receiving sheet obtained in the same manner as in Example 1 were overlapped as shown in FIG. 4 and filled in with a pencil. Then, the written image on the transfer sheet was erased with an eraser. The red color image 15 of the color forming area 5 did not disappear and could not be tampered with. Further, since the written image 12 and the image 15 of the self-coloring area are formed on the same surface, the confirmation can be performed very easily. Moreover, although the surface of the transfer sheet was of the self-coloring type, stains during handling were not noticeable. Furthermore, the purple color image on the receiving sheet could not be additionally written because the color tone was different on a general-purpose transfer sheet.

Example 3 [Preparation of blue-colored red-colored mixed ink] To the red-colored mixed ink of Example 1, 1 part of crystal violet lactone was added and dispersed to obtain a blue-colored red-colored mixed ink. [Preparation of Transfer Sheet] A transfer sheet was obtained in exactly the same manner except that the above red-colored mixed ink colored in blue was used in place of the red-colored mixed ink of Example 1.

[Evaluation] The above transfer sheet and the receiving sheet obtained in the same manner as in Example 1 were overlapped as shown in FIG. 1 and filled in with a pencil, and the written image on the transfer sheet was erased with an eraser. The red color image 15 of the color forming area 5 did not disappear and could not be tampered with. Moreover, when the image 15 in the self-coloring area of the transfer sheet is erased with the desensitizing component to prevent tampering, it was found that the blue coloring in the area disappeared, making tampering more difficult. Also, the image 12
Since the image 15 of the self-coloring area is formed on the same surface, the confirmation can be performed very easily. Moreover, although the surface of the transfer sheet was of the self-coloring type, stains during handling were not noticeable.

[0041]

As is apparent from the above evaluation, the tamper-proof pressure-sensitive copying sheet of the present invention has excellent tamper-proof property and is excellent in confirmation workability. Further, although the surface of the transfer sheet was of the self-coloring type, stains during handling were not noticeable.

[0042]

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing the structure of a tamperproof pressure-sensitive copy sheet of the present invention.

FIG. 2 is a sectional view showing the structure of a tampering prevention pressure-sensitive copy sheet of the present invention.

FIG. 3 is a cross-sectional view showing the structure of a tamperproof pressure-sensitive copy sheet of the present invention.

FIG. 4 is a cross-sectional view showing the structure of the tampering prevention pressure-sensitive copy sheet of the present invention.

FIG. 5 is a cross-sectional view showing the structure of a conventional tamper-proof pressure-sensitive copy sheet.

[Explanation of Codes] 1: Tamper-proof pressure-sensitive copy sheet of the present invention 2: Transfer sheet 3: Support 4: Coloring agent A-encapsulating microcapsule layer 5: Self-coloring layer 6: Coloring agent B-encapsulating microcapsule 7: Color developer 8: Receiving sheet 9: Support 10: Color developer layer 11: Writing tool 12: Writing image 13: Copy image 14: Copy image 15: Tamper-proof recording image 16: Coloring agent B-containing microcapsule layer 17: Coloring agent C-encapsulating microcapsule layer 18: Conventional tamper-proof pressure-sensitive copy sheet

Claims (5)

[Claims] 1. A pressure-sensitive copying sheet in which a transfer sheet having a color-forming agent-encapsulating microcapsule layer on the back surface of a support and a receiving sheet having a developer layer on the surface of the support which develops a color by reacting with the color-forming agent are combined. In addition, tampering prevention, characterized in that a part of the surface of the transfer sheet contains a color-forming agent-encapsulating microcapsule and a color-developing agent, and at least one of the components is provided with a self-color-forming area supplied by printing. Pressure-sensitive copy sheet for. 2. The tamperproof pressure-sensitive copying sheet according to claim 1, wherein the self-coloring area on the surface of the transfer sheet is provided by printing a mixed ink of a color-forming agent-encapsulating microcapsule and a color-developing agent. 3. The tamperproof pressure-sensitive copy sheet according to claim 1, wherein at least a part of the self-coloring area of the transfer sheet is colored with a decolorizable material. 4. The tamperproof pressure-sensitive copy sheet according to claim 2, wherein the layer printed with the mixed ink of the color-forming agent-encapsulating microcapsules and the color-developing agent is colored with a decolorizable material. 5. The back surface of the transfer sheet is divided into areas of microcapsule layers having different coloring colors.
The tamper-proof pressure-sensitive copy sheet according to claim 4.