JPH04155632A - Thermal recording medium - Google Patents

Abstract

PURPOSE:To facilitate the reading of a data of balance, frequency or the like by visual inspection by providing a first thermal color formation layer with a higher color formation density in a visible light area beneath a second thermal color formation layer. CONSTITUTION:A magnetic recording layer 2 is provided on the surface of a card base body 1 and a concealing layer 3 is provided thereon to make the recording layer 2 invisible. Moreover, a first thermal color formation layer 4 is provided on the concealing layer with such a characteristic that a spectrum of a color formation part 4-1 presents a photoabsorption in a visible light area when heat energy is applied to display a data 7 of manetary value, balance or the like with the formation of color. Then, being laminated on the first layer, a second thermal color formation layer 5 is provided with such a characteristic that the spectrum of a color formation part 5-1 presents a photoabsorption not only in the visible light area but also in an infrared area when the data 7 is displayed just as done in the first thermal color formation layer 4. Thus, a density of the color formation part of the first thermal color formation layer 4 is added to that of the color formation part 5 of the second thermal color formation layer 4 to enhance the density thereof.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a heat-sensitive recording medium, and particularly to improving the coloring density of a heat-sensitive coloring layer thereof.

[Conventional technology]

Magnetic recording media are widely used in credit cards, ID cards, commuter passes, and prepaid cards such as telephone cards because they allow information to be easily written, read, and rewritten, and can be manufactured at low cost.

By the way, in recent years, in prepaid cards and the like, in order to display the balance, the number of degrees, etc., a thermosensitive coloring layer is provided on the medium to thermally record and display the information. Furthermore, the displayed contents are not only visually recognized but also mechanically read using an optical character reader, a barcode reader, or the like. In these devices, a light emitting diode or a semiconductor laser whose spectrum has a peak in the infrared region is used as a light source. Therefore, the heat-sensitive color forming layer that displays the above-mentioned balance level can be machine-readable by the above-mentioned optical reading device by using a dye or a color developer whose color-forming portion exhibits light absorption even in the infrared region. It is carried out.

Various dyes and color developers that absorb light in the infrared region have been developed, and some of them have reached a level where the colored parts can be read mechanically using an optical reader. Still, none of them are fully satisfactory for visual reading due to insufficient color density.

[Problem to be solved by the invention]

As mentioned above, in heat-sensitive recording media such as pass tickets, gift certificates, Talegift cards, ID cards, commuter passes, and price tags, which have a heat-sensitive color-forming layer in which the color-forming part shows light absorption in the infrared region, the balance, The degree and other information is displayed by thermally coloring the thermosensitive coloring layer using a thermal head, and the content is read mechanically using an optical character reader, and the level of display is generally satisfactory. However, the color density is too low for visual reading, so it is currently not at a sufficient level.

[Means to solve the problem]

In order to solve the above problems, the present invention develops a color using thermal energy on a concealing layer made of a material that reflects visible light and infrared rays, and the spectrum of this colored part shows light absorption in the visible light range, and the color density provides a first thermosensitive coloring layer having darker characteristics than a second thermosensitive coloring layer, which will be described later;
Furthermore, a second thermosensitive coloring layer is provided on the first thermosensitive coloring layer, which also develops color due to thermal energy, and whose coloring portion exhibits light absorption in the infrared region as well as in the visible light region.

[Effect]

When the second thermosensitive coloring layer is used alone, the density of the coloring part is not sufficient for visual reading when thermal energy is applied to develop the color, but as mentioned above, the coloring density is higher than that of the second thermosensitive coloring layer. By providing the first thermosensitive coloring layer that has a deep color, when thermal energy is applied to color the first and second thermosensitive coloring layers, the density of the coloring part of the second thermosensitive coloring layer will be the same as that of the first. The density increases with the addition of the density of the coloring part of the thermosensitive coloring layer, making it easy to read visually.

〔Example〕

An embodiment of the present invention will be described in detail below with reference to the drawings. FIGS. 1 and 2 show an embodiment in which the present invention is applied to a prepaid card. FIG. 1 is a plan view of the back of the card, and FIG. Fig. 3 shows cross-sectional views according to the respective figures.

In manufacturing the prepaid cards shown in Figures 1 and 2,
First, a magnetic recording layer 2 is provided on the surface of a card base I, and a concealing layer 3 that makes the magnetic recording layer invisible is provided thereon. Furthermore, when thermal energy is applied to this to make it color and display the data 7 of amount and balance, the spectrum of the coloring part 4-1 shows light absorption in the visible light range. When the coloring layer 4 is provided and the data 7 is displayed in the same way as the first thermosensitive coloring layer 4, the spectrum of the coloring layer 5-1 shows light absorption not only in the visible light region but also in the infrared region. In the illustrated card, a second heat-sensitive coloring layer 5 having such characteristics is provided, and a protective layer 6 is sequentially laminated thereon, if necessary, for the purpose of imparting durability and resistance.

In this case, the material of the card base 1 is polyester,
Plastics such as polyvinyl chloride, polymethyl methacrylate, polycarbonate, polyethylene, polystyrene, and nylon, paper, synthetic paper, and impregnated paper may be used alone or in combination.

The magnetic recording layer 2 is made of r Fetus, Co-coated γFe,
Os, Fe304, CrO2, Fe, Fe-Cr,
Fe-Co, Co-Cr, Co-Ni, MnAl, B
A coating liquid in which magnetic materials such as a ferrite and Sr ferrite are dispersed in a binder solution or ink vehicle consisting of a suitable polymer binder and solvent is applied using the gravure method, roll coating method, bar coater method, or screen printing method. It is formed by coating and drying using a known coating method such as. In addition,
If the magnetic material is a metal chain, it can be formed by known means such as sputtering, plating, and vacuum deposition.

Hiding layer 3 is made of Ag, Cu, AI, Zn, and Sn.

Non-magnetic metal powders with hiding power such as Pb, Bi, Ge, In, etc. are combined with hydroxyethyl cellulose, carboxyl methyl cellulose, polyvinyl alcohol, styrene/maleic acid copolymer, polymethacrylic acid resin, polystyrene, acrylic/styrene copolymer, Polyester, ABS
A resin, nitrocellulose, vinyl acetate, or other polymeric binder alone or a mixture thereof is dispersed in a binder solution, and the coating liquid is applied onto the magnetic recording layer using the coating method described above.

The first thermosensitive coloring layer 4 is composed mainly of a polymeric binder and a thermosensitive coloring agent, and is formed by dissolving the polymeric binder in a solution in which the thermosensitive coloring agent is dispersed in water or an appropriate solvent. A coating liquid consisting of the following is applied onto the concealing layer by the above-mentioned coating method and dried. Examples of polymer binders include hydroxyethyl cellulose, carboxymethyl cellulose, polyvinyl alcohol, styrene/maleic acid copolymers, methacrylic resins alone or copolymers such as polymethyl methacrylate, polystyrene, acrylic/styrene copolymers, and polyester resins. , ABS resin, nitrocellulose, etc. can be used.

Additionally, heat-sensitive coloring agents can be broadly classified into two types: metal compound types and dye types. Specifically, the metal compound coloring types include ferric stearate, a combination of ferric myristate and tannic acid and gallic acid, and Ag oxalate.
, combination of Pb, Hg, Th salt and sodium thiogate, Ni, Co, , Cu salt of stearic acid and CaS,
SrS, combination with BaS, silver oxalate, mercuric oxalate and glycerin, combination with polyhydroxy alcohol, silver hehenate, silver stearate and hydroquinone, combination with spiroindane, ferric laurate,
A combination of ferric pelargonic acid and thiocetyl chloride may be used. On the other hand, the dye type is
It is a combination of a color developer having a phenolic hydroxyl group and a colorless leuco dye, and the color developer includes 4°4°-isopropylidenephenol, hensyl-P-hydroxyhenzoate, and 4.4°-dihydroxy-3,5. Examples of leuco dyes include diallyldiphenyl sulfone, methyl-bis(hydroxyphenyl) acetate, gallic acid ester, and P-phenylphenol.
Crystal Violin Roughton, 3-Indolino-3
-P-dimethylaminophenyl-6-cyphthylaminophthalide, 3-dimethylamino-7-chlorofluoran,
2-(2-chlorophenylamine)-diethylaminofluorane, 2-(2-fluorophenylamino)-6-
Diethylaminofluorane, 2-(2-fluorophenylamino)-6-di-n-butylaminofluorane, 3
-diethylamine-7-cyclohexylfluorane, 3
-diethylamino-5-methyl-7-t-butylolane and the like. In addition to the above-mentioned heat-sensitive color forming agents or a combination thereof, any heat-sensitive color forming agent used in the present invention may be used as long as it satisfies the above-mentioned conditions.

The second heat-sensitive color forming layer 5 is mainly composed of a polymer binder and a heat-sensitive color former, and is formed by dissolving the polymer binder in a solution in which the heat-sensitive color former is dispersed in water or an appropriate solvent. Coating a coating liquid on the first heat-sensitive coloring layer 4 by the coating method described above,
Dry and form.

As the polymer binder, hydroxyethyl cellulose,
carboxymethylcellulose, polyvinyl alcohol,
Styrene/maleic acid copolymer, methacrylic resin alone or copolymer such as polymethyl methacrylate, polystyrene, acrylic/styrene copolymer, polyester resin,
ABS resin, nitrocellulose, etc. can be used. on the other hand,
The heat-sensitive color former is a combination of a leuco dye that absorbs light in the infrared region and an acidic substance such as phenol. The main examples of each are dyes such as tri(
P-aminophenyl) fluorene (JP-A-59-199
757), 3.3-bis[2-(4-dimethylaminophenyl)-2-(4-methyoxyphenyl)ethynyl)
-4,5,6,7-tetrachloro-1 (3H)-isovincyfluanone (JP-A-62-243653), 3-
(4-(4-phenylaminophenyl)aminophenylcoamino-6-methyl-7-chlorofluoran (Japanese Unexamined Patent Publication No. 63-118290), etc.).

In addition to the above-mentioned heat-sensitive coloring agents used in the present invention, any one having light absorption in the infrared region can be used.

The protective layer 6 is formed by applying a coating liquid containing a polymeric binder as a main component and dissolving this in a solvent by the above-mentioned coating method and drying. As the polymer binder, the same polymer binder as used in the above-mentioned thermosensitive coloring layer is used, but thermosetting resins and ultraviolet curable resins may also be used. Furthermore, a lubricant or the like may be added for the purpose of improving thermal head suitability.

Data such as the balance and the number of degrees are displayed on the prepaid card constructed as described above by applying thermal energy to the first and second thermosensitive coloring layers using a thermal head to cause them to develop color. The spectrum of this colored area is shown in FIG.

The single-dot chain wA8 in the figure is the coloring part 4- of the first thermosensitive coloring layer 4.
1, the chain double-dashed line 9 indicates the second thermosensitive coloring layer 5
The solid line 10, which is an independent spectrum of the coloring portion 5-1, is the spectrum when the 1.2 heat-sensitive coloring layers in the configuration of the present invention develop color at the same time. Moreover, the dotted line 11 is the spectrum of the non-coloring part. As can be seen from the figure, when comparing individual spectra, in the visible light range, the reflectance of spectrum 8 of the first thermosensitive coloring layer is higher than that of spectrum 9 of the second thermosensitive coloring layer.
Furthermore, in the infrared region, the reflectance of spectrum 9 of the second thermosensitive coloring layer is lower than that of spectrum 8 of the first thermosensitive coloring layer. In the spectrum 10 that is simultaneously colored according to the present invention, in the visible light region, the second
Since the light that is not absorbed by the heat-sensitive coloring layer is absorbed by the first heat-sensitive coloring layer below, the reflectance is lower than when the second heat-sensitive coloring layer is used alone. In addition, in the infrared region, most of the infrared rays are absorbed by the second thermosensitive coloring layer, so almost all of the infrared rays are absorbed by the second heat-sensitive coloring layer.
It has a reflectance comparable to that of the heat-sensitive coloring layer. That is, in the visible light range, the reflectance is lower than when the second heat-sensitive coloring layer is used alone, so the density becomes higher and data such as balance and power can be easily checked visually.

Next, there is a method of reading data such as balance, degree, etc. using an optical character reader or the like, which is done by irradiating the data with infrared rays. As this infrared light source, 7
A light emitting diode or a semiconductor laser having a wavelength peak at 00 nm or more is used. That is, when the infrared rays emitted from these light sources hit the data area, they are absorbed and the infrared rays are not reflected, but the surrounding non-colored areas reflect infrared rays as shown by the spectrum 11 of the non-colored area in FIG.

These large differences in the amount of reflected infrared rays are electrically processed and read as data.

Although the present invention has been described above using a thermosensitive magnetic recording medium as an example, the present invention is not limited thereto, and can also be applied to a recording medium that does not have a magnetic recording layer in a part thereof.

Furthermore, the configuration of the present invention will be explained using a specific example. Note that "parts" in the text indicate parts by weight.

Main 1 (a) Coating composition of M1 recording layer aO6FezOt 40 parts Salt-vinyl acetate resin 10 parts (Tanesui Chemical Co., Ltd., trade name: Eslenoku AJ) Saturated polyester resin 5 parts (Toyobo Co., Ltd.) Product name"
Byron 103J) polyurethane elastomer
7 parts (manufactured by Nippon Polyurethane Co., Ltd., product name r)
N-2304j) Oleic acid 5 parts Toluene 30 parts Isonoa hardening agent 3 parts (manufactured by Nippon Polyurethane Co., Ltd., trade name "Kolo 7-" HLJ) Triethylenediamine 0.5 parts (b
) Coating liquid composition of concealing layer Salt vinyl acetate resin 10 parts CUC
Made by C (product name: rVAGH) AL silk powder 5 parts MEK
90 parts (c) Coating liquid composition of the first heat-sensitive coloring layer Ferric myristate 5 parts Tannin 9 1.5 parts Methacrylic resin 10 parts (Mitsubishi Rayon Co., Ltd., trade name: rBR-6°) Toluene 70 parts (d)
Coating liquid composition of second heat-sensitive coloring layer Dye 1 part Color developer (bisphenol A) 2.5 parts Methacrylic resin 70 parts (Mitsubishi Rayon (
Co., Ltd. (trade name: rBR-60) Toluene 70 parts (e)
Composition of protective layer coating liquid: Zinc stearate 1 part Methacrylic resin 8 parts (Roam &
Manufactured by Haas Product name: "Valaloid A-IIJ" Toluene 9 parts Above (
Among the materials for the magnetic recording layer coating solution in a), the material that does not contain an inshift hardener is uniformly dispersed in advance using a sand mill for 2 hours, and the coating solution to which an isonanoate hardener is added at the time of coating is applied to a thickness of about 188 μm. A roll coater equipped with an orientator so that the dry film thickness is approximately 15μ on white polyester.
It was formed by coating and drying. A concealing layer coating liquid having the composition (b) was applied onto this magnetic recording layer to a dry film thickness of about 5 μm and dried. On this hidden layer (
c) The heat-sensitive coloring layer coating solution having the composition of (d) is sequentially coated by an oligogravure method so that each layer has a dry film thickness of approximately 5 μm, and is dried to form a first heat-sensitive coloring layer and a second heat-sensitive coloring layer. were formed respectively.

Finally, a protective layer coating liquid having the composition (e) was applied by gravure method to a dry film thickness of approximately 2 μm, and dried to form a protective layer, thereby obtaining a sheet for thermosensitive magnetic recording media. .

To this thermosensitive magnetic recording sheet, a thermal henode applied a power of 0.45 W/dot and a pulse width of 2.5 ms.
When thermal energy was applied to develop color under the printing conditions described above, clear and densely printed characters were obtained. Also,
The printed characters were read accurately using an optical character reader equipped with a near-infrared light source.

[Effects] As explained above, by providing the first thermosensitive coloring layer which has a higher coloring density in the visible light range under the second thermosensitive coloring layer, when the second thermosensitive coloring layer is used alone, Since the color density is higher than that of the original, it is possible to easily read data such as balance and frequency by visual inspection.

[Brief explanation of drawings]

Fig. 1.2 is a diagram showing an embodiment in which the present invention is applied to a prepaid card, Fig. 1 is a plan view of the back side of the card, and Fig. 2 is a diagram taken along the Cross section, 3rd
The figure shows the spectra (
FIG. 2 is an explanatory diagram of spectral reflectance characteristics. 1, Card base 2, M1 recording layer 3, Hiding layer 4, First thermosensitive coloring layer 5, Second thermosensitive coloring layer 6, Protective layer 7, Data patent Applicant Toppan Printing Co., Ltd. Representative Kazuo Suzuki Figure 2 400 500 600 700 800
900 nm wavelength diagram 3

Claims (2)

[Claims] (1) At least on the base material, there is a concealing layer that exhibits high reflectance to visible light and infrared rays, and a portion colored by thermal energy exhibits high absorption to visible light, and the coloring density is as described below. a first thermosensitive coloring layer that has a higher color density than the colored portion of the second pressure-sensitive coloring layer;
1. A heat-sensitive recording medium characterized in that a portion colored by thermal energy is formed by laminating a second heat-sensitive coloring layer that exhibits high absorbency to infrared rays. (2) The thermosensitive recording medium according to claim 1, wherein the magnetic recording layer is hidden by a hiding layer.