JP2579272B2 - Recording method - 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 recording image information, and more particularly to a method for recording image information which cannot be read by the naked eye and can be read only by infrared rays.

[0002]

2. Description of the Related Art Conventionally, bank passbooks, checks, air tickets, road toll tickets, tickets, admission tickets, prepaid cards, for example, telephone charge cards, ticket purchase cards, admission ticket purchase cards, games Cards related to automatic payment such as fee cards, identification cards, bank deposit number cards, etc., as well as concealment of secret documents, materials, information, etc.
Recorded image information such as letters, numbers, symbols, patterns, etc. may need to be kept confidential to third parties and concealed so as not to be misused. In many cases, magnetic ink is used using magnetic ink. Was.

[0003] However, in a system using magnetic ink, there is a problem that the magnetic strength changes or disappears when the magnetic material used is exposed to heat or placed in an environment with a strong magnetic field. is there. In addition, when forming a magnetic mark, it is very difficult to uniformly disperse the magnetic material in the ink, and it is quite difficult to stably store and uniformly coat the magnetic material, and the forming method is complicated. There is a problem that is. Therefore, an object of the present invention is to easily and easily input information such as writing and recording of information, and it is generally not readable by the naked eye,
An object of the present invention is to provide a method for recording image information which can be read only by a specific means.

[0004]

The above object is achieved by the present invention described below. That is, the present invention provides a method for forming a character, a number, a symbol, a pattern,
Hidden area consisting of colored areas for recording images and infrared reflective dyes
In a method for recording image information in which the shielding layer forming colored regions are formed in a parallel or overlapping manner, the recording method is a thermosensitive coloring method,
Oxin or its derivative and heavy metal
Colored metal chelation by combining compounds containing ions
A dye intermediate that forms a compound,
2-hydroxy-α-benzoca as a coupling component
Lubazole-carboxylic acid allylamide or derivative thereof
And the two types of colored regions are substantially indistinguishable or difficult to distinguish with the naked eye before and after recording by the above method , and are recorded by the above method.
Is a recording method characterized by being readable by infrared rays .

[0005]

[Function] Writing and recording of information by recording image information consisting of a colored region made of an infrared absorbing dye and a colored region made of an infrared reflective dye on an arbitrary substrate in a parallel or overlapping manner by a thermosensitive coloring method. Can be easily and easily input, and image information which cannot be read by the naked eye and can be read only by a specific means can be recorded.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION Next, the present invention will be described in more detail with reference to preferred embodiments. As the substrate used in the present invention, for example, paper, chemical fiber mixed paper, synthetic paper,
A conventionally known recordable or recordable substrate such as a plastic film or a plastic sheet is used. The shape of the substrate to be used is not limited to each standard size, but is also used for a cut card size and the like.

In the present invention, a method for recording information on the above-mentioned substrate by using an infrared absorbing dye and an infrared reflecting dye described later is a thermosensitive coloring method. With respect to the dye used in the recording method of the present invention, in the present invention, at least one of the above two dyes utilizes a dye intermediate which generates any of the above dyes that develops color upon heating . Examples of the dye intermediate include a case where the color is formed immediately by heating and a case where the color is formed by separately acting a developer. Infrared absorbing dyes used to form image information such as letters, numbers, symbols, and patterns, or dyes formed from dye intermediates, have a large absorption in the infrared region used for detection, and It is necessary that the reflectivity of infrared radiation is clearly low or almost non-existent.

In addition, an infrared reflective dye or a dye formed from an intermediate of the dye used for visually concealing or deceiving the image information, the dye formed from the intermediate of the dye is added to the infrared region used for the detection. It is necessary to have sufficient reflectivity to show a clear difference from the low reflectivity due to absorption of light. For example, as the dye intermediate, any of known dyes having the above-described properties and intermediates that produce the dye can be used.

For example, compounds containing oxine such as oxine, alkyloxin and dichlorooxin and derivatives thereof and heavy metal ions such as ferric ion and vanadium ion, for example, water-soluble inorganic salts, lower fatty acid salts and higher fatty acid salts By processing with a combination of
It forms a colored chelate compound that absorbs infrared rays.

As the infrared absorbing dye or its intermediate used for inputting and recording of image information, any conventionally known pigments or dyes having such properties or their intermediates can be used, and particularly preferred. Things, for example,
Examples include carbon black pigments, aniline black pigments, iron oxide black pigments, titanium oxide-based black pigments, and spinel-type structural black pigments, and intermediates thereof.

As the infrared-reflective dye or its intermediate used to make the image information invisible or deceptive to make it indistinguishable, a conventionally known dye or intermediate having such properties should be used. For example, organic pigments and dyes or intermediates include phthalocyanine, azo, azomethine, azomethine azo, anthraquinone, perinone / perylene, indigo / thioindigo, dioxane, quinacridone, and isoindolin These are pigments and dyes such as linones or intermediates thereof, and the dyes or intermediates thereof are used alone or in combination of two or more.

Among the above-mentioned infrared reflective dyes or intermediates, particularly preferred dyes having an azomethine group or intermediates thereof include, for example, JP-A-58-174446 and JP-A-59-4775. Patent No. 10638
No. 16, Japanese Patent No. 1052019, Japanese Patent No. 11415114, Japanese Patent No. 11415115, Japanese Patent Application No. 60-168540, Japanese Patent Application No. 60-168.
Dyes and intermediates disclosed in 277929.

[0013] 2-Hydroxy -α- benzocarbazole particularly as a coupling component - azo pigments having an azomethine group using local carbon acid allylamide and its derivatives, it shows the color tone of dark green to black color under visible light, particularly black Shows clear black with high blackness. However, it hardly absorbs infrared rays and shows high reflectivity. The dye having an azomethine group described above has heat resistance,
It has excellent light resistance, water resistance, and chemical resistance, and has a higher coloring power. In addition, pigment-type dyes exhibit extremely excellent solvent resistance.

The above are examples of the infrared-reflective dyes and intermediates thereof particularly preferably used in the present invention. In the present invention, other dyes and mixed colors such as red,
Compound colors obtained by mixing blue, yellow, orange, purple, green, and brown dyes can also be used as infrared reflective dyes.
Note that, in the present invention, "infrared reflective dye" refers to a case in which the substance itself reflects infrared light, and the substance itself transmits infrared light, but a substrate coated with the dye, for example, paper or a plastic sheet, Infrared rays are reflected by a metal or the like, and the dyes have the property of emitting infrared rays through the colored portions again. Therefore, in the present invention, a dye having high infrared transmittance is also included in the “infrared reflective dye” of the present invention.

The above-mentioned dye or dye intermediate is used as a recording ink or the like or a coating agent containing the dye or the dye intermediate. For example, it is used in the same configuration as a conventionally known recording ink or the like and a coating agent system. For example, an aqueous system is an aqueous solution system, an aqueous emulsion system, an aqueous dispersion system or a mixture thereof, and also an oil system. Oil-based solution, oil-based emulsion, oil-based dispersion or a mixture thereof.

The resin components used in these recording inks and coating agents are conventionally known, and the aqueous resins include casein, sodium alginate, gum arabic, ethylcellulose, hydroxyethylcellulose, polyvinyl alcohol and styrene. Water-soluble salt of maleic acid ester copolymer, water-soluble salt of (meth) acrylic ester (co) polymer, water-soluble salt of styrene- (meth) acrylic ester latex, water-soluble alkyd resin, styrene- Butadiene copolymer latex,
(Meth) acrylic ester-based copolymer latex, styrene- (meth) acrylic ester-based copolymer latex, ethylene-vinyl acetate-based copolymer latex, polyethylene-based disversion, ethylene-based copolymer-based disversion, and the like. .

The resin component for oily system includes cellulose acetate butyrate resin, nitrocellulose resin, vinyl acetate (co) polymer, styrene (co) polymer, vinyl chloride-vinyl acetate copolymer. Coalesce, ethylene-vinyl acetate copolymer, polyvinyl butyral resin, alkyd resin, phenol-modified alkyd resin, styrenated alkyd resin, amino alkyd resin,
Polyester resin, polyurethane resin, acrylic polyol urethane polymer, soluble polyamide polymer, phenol resin, rosin modified phenol resin,
Rosin-modified maleic resin and the like can be mentioned.

When a printing method is used as a method for coloring by applying an ink containing an intermediate of a dye or an ink containing a dye for concealing recorded image information or the like, a letterpress printing, a flat printing, , Intaglio printing, gravure printing, screen printing, etc. are used, and when a coating method is used, it is selected from conventionally known methods in accordance with the coating ink, and includes a blade coater, a rod coater, a knife coater, and a squeeze. Coaters, air doctor coaters, gravure coaters, spray coatings and the like.

As described above, the formed letters, numbers,
Absorbance or low reflectivity of image information such as symbol patterns for infrared rays, and the reflectivity for infrared rays of the colored surface applied to conceal or deceive those image information with naked eyes and their degree, It can be confirmed by an infrared reader or an infrared photograph. For example, an infrared reader first uses a semiconductor laser that emits near-infrared light of 700 to 900 nm or an infrared light emitting diode that emits infrared light near 790 nm. These infrared rays are irradiated as they are or in a form in which the sensitivity of light reception is increased by adding modulation.

Next, the infrared light reflected by the colored portion of the base material, for example, paper or card, on which no image information is recorded, is received by the light receiving sensor and converted into an electric signal indicating reflection. In the recorded portion, the irradiated infrared light is absorbed, and the infrared light receiving sensor receives little or very low light, and shows no reflection or is converted into a low electric signal. These electric signals are connected to various recognition methods such as a display using a cathode ray tube and recognized as clear information.

[0021]

EXAMPLES The present invention will now be described specifically with reference to examples. In the following description, parts and% are by weight unless otherwise specified. Example 1 1 part of powder obtained by encapsulating 1 part of oxine with 30 parts of gelatin-gum arabic-stearic acid (weight ratio 1: 1: 4) and 1 part of ferric stearate, and 1.6 parts of ethylcellulose A thermosensitive coloring ink using acetone as a solvent as a binder was applied to a sheet of synthetic paper to a thickness of about 3 μm to obtain a pale yellow sheet. It turns black when heated to develop color. Before and after developing the sheet, the reflectance of the visible portion to the near-infrared portion was measured using a 330 type self-recording spectrophotometer manufactured by Hitachi, Ltd. in order to check the properties with respect to visible light and infrared light. The reflectance at each wavelength was as shown in Table 1 below.

[0022]

[Table 1]

In the above table, wavelengths are given in nm and R
-1 is a sheet before coloring, and A-1 is a sheet which has been heated and colored. The reflectance was measured by applying an alumina white plate from the back. The above results show a high reflectance in the visible and near-infrared regions before heating and coloring, but those that have been heated and colored show almost no reflection in the visible region and absorb, showing black. Large absorption is shown also in the near infrared region in the range of about 800 to 1,000 nm.

Separately, 3- (4'-aminophenylimino)
It was obtained by diazotizing -1-oxo-4,5,6,7-tetrachloroisoindoline and performing a coupling reaction with 2-hydroxy-α-benzocarbazole-3-carbo- (4′-methoxy) anilide. A black ink R-2 containing 1 part of a black pigment, 3 parts of ethyl cellulose as a binder, and acetone as a solvent was prepared. This was coated on paper to a thickness of about 3 microns. The reflectance of the visible portion and the near-infrared portion of this black coated paper was measured in the same manner using the above-described spectrophotometer. The reflectance at each wavelength is shown in Table 1 below.
It was as follows.

[0025]

[Table 2]

In Table 2 above, the wavelength is shown in nm, and R
-2 indicates black coated paper. In the visible part, it shows almost no reflection and is absorbed, so it naturally shows black, but in the near-infrared part it shows very high reflection.
The above black ink was applied on the sheet coated with the above thermosensitive coloring ink to a thickness of about 3 μm to obtain a black sheet. This sheet was heated and printed by a thermal recording apparatus. However, this print could not be read by the naked eye because the sheet was applied in black. However, the reflectance of the visible portion and the near-infrared portion of the non-colored portion and the printed color portion of the black sheet were measured in the same manner using the spectrophotometer. The reflectance at each wavelength was as shown in Table 3 below.

[0027]

[Table 3]

In Table 3 above, wavelengths are shown in nm,
R-3 is a portion of the black sheet that is not colored by heating,
A-3 is a heated color-developed portion of the black sheet. The above results indicate that the black sheet absorbs almost no reflection in the ultraviolet and visible regions and absorbs light, but naturally exhibits a high reflection in the near infrared region. On the other hand, the heated and colored portion absorbs almost no reflection in the ultraviolet and visible regions and shows black, but further shows a large absorption in the near infrared region of 800 to 1,000 nm. I have.

From the above, the heat-sensitive recording sheet coated with the black ink R-2 is black when viewed with the naked eye in both the non-heat-developed portion and the heated-colored portion. The portion which is not colored by heating shows a high reflection against the irradiation of infrared rays, whereas the portion which is colored by heating has a heated coloring portion A-1 at about 800 to 1,000 nm.
, And the reflection is significantly reduced. The difference between the two properties is very large. Based on the above findings, a thermosensitive coloring ink was applied to a sheet made of synthetic paper, a black ink R-2 was further applied thereon, and then cut into a card having a width of 85 mm and a length of 54 mm.

The card was used to record image information such as letters, numbers, symbols and patterns using a thermal printer. However, since the appearance of the recording medium was entirely black, the recorded information was indistinguishable to the naked eye, but clear information could be read by an infrared reader. The infrared reader described above generates an infrared ray by an infrared light emitting diode (for example, TLN105 manufactured by Tokyo Shibaura Electric Co., Ltd.), modulates it to increase the luminous intensity, and receives the infrared light reflected by the recording medium by a light receiving sensor (for example, Tokyo Shibaura Electric Co., Ltd.) TPS703), the presence or absence of reflection and the degree of reflection are converted into electrical signals so that information can be recognized.

[0031]

According to the recording method of the present invention as described above, the formed recording information is colored in the same or a darker hue so as to be concealed or deceived with the naked eye, so that the recorded information can be identified with the naked eye. Cannot be identified, and can be identified only by infrared rays. Therefore, it is very useful as a method for recording image information requiring high secrecy.

 ──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-62-278084 (JP, A) JP-A-61-297192 (JP, A) Jikai Sho 61-2964 (JP, U)

Claims (1)

(57) [Claims] 1. A colored region for recording an image such as a character, a numeral, a symbol or a pattern made of an infrared-absorbing dye and a colored region for forming a concealing layer made of an infrared-reflective dye are formed in parallel or on an arbitrary substrate. In the method of recording image information to be recorded, the recording method is a thermosensitive coloring method, and the infrared-absorbing dye is oxidized.
Synth or its derivative and compound containing heavy metal ion
Dye intermediates forming combined colored metal chelates
Body, and the infrared reflective dye is a coupling component
2-hydroxy-α-benzocarbazole-carboxylic acid
An azo pigment using allylamide or a derivative thereof.
And the two types of colored areas are recorded before recording by the above method.
And even afterwards, it is practically indistinguishable or difficult to distinguish with the naked eye, and recording by the above method is read by infrared
A recording method characterized by being possible . "