JPH09249834A - Fluorescent ink composition and fluorescent mark formed from the fluorescent ink composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a fluorescent ink composition not generating an ooze and excellent in dispersion stability, light resistance and water resistance, to obtain a high concentration fluorescent mark formed from the fluorescent ink composition, and to obtain an infrared light fluorescent mark of being well read even when the infrared light fluorescent mark is disposed on an infrared light- absorbing article to be marked, and suitable for the highly dense formation of bar codes. SOLUTION: This fluorescent ink composition and this fluorescent mark each contains water-dispersible colloidal silica having a resin component on the surface and exhibiting fluorescence in a visible light region. The infrared light fluorescent ink composition and this infrared light fluorescent mark each contains water-dispersible colloidal silica having a resin component on the surface, absorbs infrared light in wavelengths of >=700nm and exhibits infrared light in an infrared light region.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fluorescent ink composition and a fluorescent mark formed from this fluorescent ink composition, and more specifically, it does not cause bleeding and is excellent in dispersion stability, light resistance and water resistance. Further, the present invention relates to a fluorescent ink composition and a high-concentration fluorescent mark which is free from bleeding and is excellent in light resistance and water resistance formed by the fluorescent ink composition.

[0002]

2. Description of the Related Art In recent years, information such as the manufacturer and product name of an article is displayed on a bar code, etc., and the striped pattern is read by an optical detection method to analyze the sales of the article and analysis of distribution. It is used for such as. This type of bar code is usually printed using an ink jet printer or the like, and is suitable for classification and identification of products at stores handling a wide variety of products. For this reason, not only many products using such a bar code system have recently been seen, but there are also products that apply this system to file management and the like. For example, goods are distributed by classification by code management. It is also used for postal items to which the system is applied.

However, conventionally, as a method of printing a bar code, a method of printing a black bar code on a white background has been adopted, and the method is a reflectance of a white background and a black character. Since it utilizes the difference of, when the article is soiled, it has a drawback that it becomes extremely difficult to read, and further, in this method, since reflected light in the visible region is inevitably used, It may also spoil the appearance of the article.

Therefore, as an improved type of such a black-and-white bar code, a fluorescent mark that is excited by ultraviolet light and emits visible light is used, or by exciting by infrared light, red An infrared fluorescent bar code (Tokuhyo 6-500590) that emits external light has been proposed.

[0005]

However, since a phosphor that emits visible light by being excited by ultraviolet light is essentially seen in the visible region, it not only impairs the appearance of the article, but also the black and white bar. Similar to the card, there is a problem that reading becomes difficult due to dirt on the mark.

Further, when an infrared phosphor which is excited by infrared light and emits infrared light is used, it does not emit visible light, so that the appearance of the article is affected by the presence of the bar code. Without damaging it, it is not much affected by the dirt on the mark,
Marks can be detected, but since these infrared phosphors consist of infrared fluorescent dyes that absorb and emit light in the infrared region of the wavelength, the object to be marked is an ink such as Japanese paper. When this dye is made into ink and printed by an ink jet printer or the like when it is easily absorbed, ink bleeding called a feathering phenomenon occurs, which lowers the reading rate and may cause erroneous operation. . Further, although the bar code recording tends to be high density,
In this case, since the distance between the bar codes is narrowed, this phenomenon becomes a fatal defect and poses a practical problem.

Further, since these conventional inks have the property of dyeing a mark object, which is an inherent property of dyes,
It is difficult to read when the object to be marked absorbs infrared light, for example, when it is black, and the organic dye used in this ink has poor light resistance and water resistance, and the formed mark is There is a problem that it becomes impossible to decipher.

There is also an example in which an inorganic compound containing neodymium, yttrium or the like is used as an infrared phosphor (US Pat. No. 4,202,491, Japanese Patent Publication No. 54-223).
26, JP-A-53-9607, etc.), but since these inorganic phosphors have a slow rising speed for emitting infrared light,
When a mark such as a bar code is read at high speed, there is a problem that the mark cannot be discriminated because the mark and the adjacent mark overlap.

The present invention has been made as a result of various investigations in view of the present situation, and it is possible to prevent dispersion, dispersion stability,
Provided with a fluorescent ink composition having excellent light resistance and water resistance, when a fluorescent mark is formed using a printing device such as an inkjet printer, there is no bleeding and a high concentration excellent in light resistance and water resistance. The fluorescent mark (1) is obtained.

Even when the infrared fluorescent mark is provided on the mark object that absorbs infrared light, good reading can be performed, and the mark object is not limited and the bar mark is not limited. An infrared fluorescent mark suitable for increasing the density of the code.

Furthermore, there is no sedimentation and good storage stability,
It is an object of the present invention to provide an ink composition having excellent redispersibility and having no practical problem even when the ink is not solidified and dried and solidified.

[0012]

The fluorescent ink composition of the present invention contains water-dispersible colloidal silica having a resin component on its surface and exhibits fluorescence in the visible light region. Further, it contains water-dispersible colloidal silica having a resin component on the surface, absorbs infrared light having a wavelength of 700 nm or more, and emits light in the infrared region.

Further, the fluorescent mark of the present invention contains water-dispersible colloidal silica having a resin component on its surface, and exhibits fluorescence in the visible light region. In addition, it contains water-dispersible colloidal silica having a resin component on its surface, absorbs infrared light having a wavelength of 700 nm or more, and emits light in the infrared region, and has a maximum emission power of 10 to 10 when irradiated with infrared light. 90%
The rise time is set to within 10 μsec.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION The fluorescent ink composition of the present invention comprises
Since the surface contains water-dispersible colloidal silica having a resin component, silica particles do not precipitate in the ink solution, and good printing characteristics can be obtained even in a jet type head such as an inkjet printer.

Further, since the fluorescent ink composition of the present invention contains a water-dispersible colloidal silica having a resin component on the surface together with the fluorescent dye, the fluorescent dye binds to the resin component on the surface of the water-dispersible colloidal silica to form silica. It is possible to obtain an ink composition having excellent dispersion stability without separating the particles from the dye.

Furthermore, the fluorescent ink composition of the present invention comprises
Since it contains water-dispersible colloidal silica, even in an organic solvent system such as a ketone solvent, the resin component on the surface of the silica particles is partially dissolved in the solution, and the dissolved resin component and the fluorescent dye bind to each other, thereby printing an image. Even in this case, good printing characteristics can be obtained without the dye separating from the ink medium.

When used for an ink jet printer, the redispersibility of the ink is required, and therefore it is necessary that the ink composition does not form a film. Since it contains a water-dispersible colloidal silica having a resin component, it has excellent dispersibility and can secure the same wettability with a solvent as in the case of only conventional dyes.

The water-dispersible colloidal silica having a resin component on the surface of the present invention has a greater hiding property as the particle size increases. Therefore, the larger the particle size, the clearer the image. From the viewpoint of versatility, the particle diameter is preferably 5 nm or more and 1 μm or less.

As the water-dispersible colloidal silica having a resin component on such a surface, those obtained by coating acrylic acid, methacrylic acid, crotonic acid or the like on the surface of silica particles are preferably used. Examples include acrylic catalyst-modified silica sol manufactured by Nippon Shokubai Co., Ltd.

The water-dispersible colloidal silica having a resin component on the surface thereof contains a water-dispersible colloidal silica having a resin component on the surface when used in combination with a fluorescent dye and / or a white fluorescent whitening agent, and has a visible light region. In this way, an ink composition exhibiting fluorescence can be obtained, which is excellent in dispersion stability, does not cause bleeding, and is excellent in light resistance and water resistance.

When a fluorescent dye and / or a white fluorescent whitening agent is mixed with water-dispersible colloidal silica having a resin component on the surface, a colored fluorescent dye is adsorbed on the water-dispersible colloidal silica having a resin component on the surface. Thus, a fluorescent organic pigment in which the properties of the fluorescent dye and / or the white fluorescent whitening agent are maintained as they are is obtained, and a fluorescent ink composition is obtained using such a fluorescent organic pigment. A fluorescent ink composition using such a fluorescent organic pigment has a property as a pigment, and unlike a fluorescent dye, does not cause bleeding even when used when forming a mark on paper or the like. In addition, it is excellent in dispersion stability, light resistance, water resistance, and color development. Further, since it is a pigment, it can be provided with hiding properties and can be less affected by the base during printing.

As the fluorescent dye used for obtaining the fluorescent organic pigment from the water-dispersible colloidal silica having the resin component on the surface as described above, any fluorescent dye having any structure can be used. For example, an acid dye, a direct dye, a cationic dye, A mordant dye, an acid mordant dye, a disperse dye, a reactive dye, an oxidation dye and the like are preferably used. A white fluorescent whitening agent is also preferably used alone or together with these fluorescent dyes.

Specific examples of the fluorescent dye include ACID YEL represented by a color index number (C.I).
LOW3, ACID YELLOW7, ACID RE
D52, ACID RED77, ACID RED8
7, ACID RED92, ACID BLUE9, B
ACIC YELLOW1, BACIC YELLOW
40, BACIC RED1, BACIC RED1
3, BACIC VIOLET7, BACIC VIO
LET10, BACIC ORANGE22, BACI
C BLUE7, BACIC GREEN1, DISP
ERSE YELLOW121, DISPERSE Y
ELLOW82, DISPERSE ORANGE1
1, DISPERSE RED58, DISPERSE
BLUE7, DIRECT YELLOW85, DI
RECT ORANGE8, DIRECT RED9,
DIRECT BLUE22, DIRECT GREE
N6, FLUORESCENT BRIGHTENIN
G AGENT55, FLUORESCENT BRI
GHTENING WHITEX WS52, FLUO
RESCENT 162, FLUORESCENT 11
2, SOLVENT YELLOW44, SOLVEN
T RED49, SOLVENT BLUE5, SOL
VENT PINK, SOLVENT GREEN7,
PIGMENT BLUE15, PIGMENT GR
EEN7, PIGMENT RED53, PIGMEN
Examples include TRED57 and PIGMENT YELLOW1.

Specific examples of the white fluorescent whitening agent include:
Fluorescent Brightening Ag
ent85,86,22,174,166,90,13
4,84,24,87,175,176,169,, 1
67,173,14,32,30,177,153,1
68, 37, 104, 45, 55, 52, 54, 56,
171, 170, 135, 162, 163, 164, 1
12, 121, 172, 91 and the like.

When obtaining the fluorescent organic pigment, the content ratio of the water-dispersible colloidal silica having a resin component on the surface and the content of the fluorescent dye and / or the white fluorescent whitening agent to be adsorbed depends on the water dispersibility having the resin component on the surface. Against colloidal silica
It is preferably in the range of 0.001 to 10% by weight,
If it is less than this range, a sufficient color cannot be obtained, and if it is too large, a sufficient color cannot be obtained.

When the water-dispersible colloidal silica having a resin component on the surface is used together with an organic dye and / or a white fluorescent whitening agent exhibiting fluorescence in the infrared wavelength region of 700 nm or more, water having a resin component on the surface is used. An ink composition containing dispersible colloidal silica, which absorbs an infrared wavelength of 700 nm or more and emits light in the infrared region, is excellent in dispersion stability, does not cause bleeding, and is excellent in light resistance and water resistance. A fluorescent ink composition is obtained.

Furthermore, when water-dispersible colloidal silica having a resin component on the surface is mixed with an organic dye exhibiting fluorescence in the infrared wavelength region of 700 nm or more and / or a white fluorescent whitening agent, fluorescence is emitted in the infrared wavelength region. Organic dyes and / or
Alternatively, the white fluorescent whitening agent is adsorbed on the water-dispersible colloidal silica having a resin component on the surface, and the organic dye and / or the infrared fluorescent whitening agent that retains the properties of the white fluorescent whitening agent as they are, exhibiting fluorescence in the infrared wavelength region. An organic pigment is obtained, and an infrared fluorescent ink composition is obtained using such an infrared fluorescent organic pigment. A fluorescent ink composition using such an infrared fluorescent organic pigment has a property as a pigment, and unlike a fluorescent dye, bleeding does not occur even when used when forming a mark on paper or the like. It is excellent in dispersion stability, light resistance, water resistance, and color development, and since it is a pigment, it can be provided with hiding power and can be less affected by the base during printing.

As the organic dye exhibiting fluorescence in the infrared wavelength region of 700 nm or more, those having any structure can be used, and examples thereof include polymethine dyes, anthraquinone dyes, dithiol metal salt dyes, phthalocyanine dyes,
Indophenol dyes, cyamine dyes, styryl dyes, aminium dyes, diimonium dyes, azo dyes and the like are preferably used. The same white fluorescent whitening agent as that used in the fluorescent ink composition is preferably used, and a colored dye may be further mixed.

Specific examples of the polymethine dye include IR-140 manufactured by Kodak Laboratories Chemical Co .; IR-820B manufactured by Nippon Kayaku Co., Ltd., and specific examples of the cyanine dye include Japan Photosensitive Dye. Company NK-1
144, NK-123, NK-78 and the like.
In addition, specific examples of the white fluorescent whitening agent include Mika White ACR and Kayapor 3BS manufactured by Nippon Kayaku Co., Ltd.

When an infrared fluorescent organic pigment is obtained, it is adsorbed on water-dispersible colloidal silica having a resin component on the surface.
The content ratio of the organic dye and / or the white fluorescent whitening agent exhibiting fluorescence in the infrared wavelength region of 00 nm or more is 0.001 with respect to the water-dispersible colloidal silica having a resin component on the surface.
It is preferably in the range of 10 to 10% by weight, and if it is less than this range, sufficient color and fluorescent effect cannot be obtained. Further, if the amount is too large, the color becomes too dark to obtain a sufficient color, and the concentration quenching occurs, so that the fluorescent effect cannot be obtained.

As described above, the water-dispersible colloidal silica having a resin component on the surface is used together with a fluorescent dye and / or a white fluorescent whitening agent, or the water-dispersible colloidal silica having a resin component on the surface is treated with a fluorescent substance. An ink composition using a fluorescent organic pigment having a dye and / or a white fluorescent whitening agent adsorbed thereon, and a water-dispersible colloidal silica having a resin component on the surface thereof, an organic dye having absorption in an infrared wavelength region of 700 nm or more, and / Or together with a white fluorescent whitening agent, or by adsorbing an organic dye having an absorption in the infrared wavelength region of 700 nm or more and / or a white fluorescent whitening agent to water-dispersible colloidal silica having a resin component on the surface The ink composition using the infrared fluorescent organic pigment has a water-dispersible colloidal silica having a resin component on its surface and a fluorescent substance. Dye and / or white fluorescent whitening agent or fluorescent organic pigment, water-dispersible colloidal silica having a resin component on the surface and organic dye and / or white fluorescent whitening agent or red having absorption in the infrared wavelength region of 700 nm or more It is prepared by mixing and dispersing an external fluorescent organic pigment together with a binder resin and, if necessary, a solvent.

Here, as the binder resin, any of those conventionally used can be used, and examples thereof include polyvinyl alcohol, acrylic resin, polyethylene oxide, starch, formalin condensate of naphthalene sulfonate, and carboxymethyl. Cellulose or the like is used.

As the solvent used as required, water, protic solvents such as alcohol, and aprotic solvents such as ketones and esters may be used alone or in combination. .

The fluorescent ink composition and the infrared fluorescent ink composition thus prepared are used in various printing methods such as those for ink jet printers, screen printing, offset printing, gravure printing, letterpress printing and tampon printing. , A dispersant, an antifoaming agent, a surfactant, a humectant, an antioxidant, a mildewproofing agent, a conductivity-imparting agent and the like are used depending on the case of application to various printing methods.

The fluorescent mark formed of such a fluorescent ink composition and an infrared fluorescent ink composition exhibits fluorescence in the visible light region or absorbs infrared light having a wavelength of 700 nm or more and is red. An infrared fluorescent mark that emits light in the outer region, particularly absorbs infrared light having a wavelength of 700 nm or more and emits light in the infrared region, does not absorb or emit light in the visible region, and thus impairs the appearance of the article. In addition, it is possible to form an infrared fluorescent mark which is not affected by the material and shape of the object to be marked and the stains on the mark.

Here, a mark showing fluorescence in the infrared wavelength region of 700 nm or more formed of the ink composition of the present invention,
When attached to a white mark object having a reflectance of infrared light having a wavelength of 700 nm or more of 50% or more, the reflection output of the mark object (standard white, standard colored paper laboratory: standard white No. 18) ) To C ₀
And then, infrared fluorescent Ma - When the output when measured by irradiating infrared light to click and C _1, it is preferred that the ratio of C ₀ / C ₁ is less than 4%, of C ₀ / C ₁ If the ratio is less than 4%,
Even if the reading operation is performed, it is possible to secure a reading rate that does not cause an erroneous operation.

When the infrared fluorescent mark is attached to a black object having a reflectance of 10% or less for infrared light having a wavelength of 700 nm or more, the infrared fluorescent mark is used for the infrared mark. when the output when measured by irradiating light to the C _2, and the C ₂ wherein the infrared fluorescent Ma - the ratio C ₂ / C and the output C ₁ when measured by irradiating infrared light to click preferably ₁ is 5% or more, the C ₂ / C ₁ is at least 5%, by detecting the infrared phosphor on a standard white infrared fluorescent Ma - it is read without erroneous operation click At the same time, the infrared fluorescent mark can be read without any problem even on the black mark.

On the other hand, simply the output ratio C ₀ / C ₁ on the standard white
When the ratio is 4% or less, a mark showing fluorescence in the infrared wavelength region of 700 nm or more can be detected without any problem, but when the base is colored, for example, black, especially carbon. When the mark of the infrared phosphor is provided on the mark object containing black, it is not possible to obtain a sufficient output,
It becomes a reading error and operates incorrectly. Therefore, C ₀ /
C ₁ must be 4% or less and C ₂ / C ₁ must be 5% or more.

Further, an infrared fluorescent mark attached to the mark object.
When performing high-speed reading, the response speed from the infrared fluorescent mark must be increased, but when the infrared fluorescent mark of the present invention is used, the maximum output is 10 to 10. A 90% rise time can be set within 10 μsec, and sufficient excitation light can be obtained even at high speed reading of 4 m / sec or more.

The infrared fluorescent mark thus formed can be made less susceptible to stains on the mark and ink bleeding, and is also affected by the base of the mark target. Therefore, without limiting the object to be marked, good reading can be achieved even when an infrared fluorescent mark is provided on the object to be marked having infrared absorption. As a result, an infrared fluorescent mark suitable for high density bar code can be obtained.

The reader thus obtained which can be used in combination with the mark showing fluorescence in the infrared wavelength region of the present invention has a function of irradiating infrared light and detecting infrared fluorescence. Any reader can be used without any particular problem. For example, the reader shown in FIG. 1 is used.

The reader shown in FIG. 1 will be described below. The reader shown in FIG. 1 comprises a reader optical system and a reading circuit, and the reader optical system is a semiconductor. Ray
The driver circuit 1, a semiconductor laser 2, a lens 3, a total reflection mirror-4, plano-convex lenses 5 and 6, a slit 7, a filter 8, and a photodiode 9 are included. .

The excitation light 10 emitted from the semiconductor laser 2 is focused by the lens 3 to have a diameter of 1 mm, passes through the through hole 41 formed in the center of the mirror -4, and passes through the lens 5 to red light. Irradiation is perpendicular to the plane of the outer fluorescent mark carrier 11. At this time, if the excitation light 10 is irradiated onto the Mira-4 side without being focused, a part of the excitation light 10 will be transmitted through the light transmission 41.
Since the light quantity (excitation energy) of the excitation light 10 that is cut by the outer peripheral portion of the excitation light 10 reaches the infrared fluorescence mark side, the emission output is reduced and the excitation light 10 is focused. It is necessary to regulate the diameter to be equal to or less than the diameter of the light transmitting 41.

The infrared fluorescent mark 12 is conveyed on the infrared fluorescent mark carrier 11 at a high speed.
The excitation light 10 is irradiated onto the infrared light to excite the infrared phosphor, and the fluorescence is received by the first plano-convex lens 5. The received light is reflected by the mirror-4, focused by the second plano-convex lens 6, transmitted through the slit member 7 and the filter 8, and received by the photodiode 9.

The reading circuit includes a detection circuit 13 having an amplifier circuit and a filter circuit, a binarization processing circuit 14, a decoding circuit 15, a serial interface 16 and a data processing circuit. It is composed of a personal computer 17.

[0046]

EXAMPLES Next, examples of the present invention will be described.
Needless to say, the present invention is not limited to these examples. Example 1 Acrylic modified silica sol dispersion (Nippon Shokubai Co .; acrylic modified silica sol, solid content 20% by weight, particle size 40n
m) A solution of 0.3 parts by weight of Rhodamine B (manufactured by Sumitomo Chemical Co., Ltd.) in 6 parts by weight of ethanol was added to 100 parts by weight, and the mixture was stirred and mixed to give a pink fluorescent organic pigment. Got
To this, John Krill 61 (manufactured by Johnson Polymer Co .;
Acrylic-styrene resin (solid content 30% by weight) was added in an amount of 10 parts by weight and water in an amount of 20 parts by weight, and the mixture was mixed and dispersed in a ball mill for 3 hours, and then an ink composition was prepared through a 1 micron filter. Then, the ink composition thus obtained was used to print on paper with an inkjet printer.

Example 2 Acrylic modified silica sol dispersion (manufactured by Nippon Shokubai Co .; acrylic modified silica sol, solid content 20% by weight, particle size 30 n)
m) IR-820 (manufactured by Nippon Kayaku Co., Ltd .; polymethine dye, peak of absorption wavelength: 820n) relative to 100 parts by weight.
m, peak of emission wavelength: 900 nm) 0.1 parts by weight of a solution of 8 parts by weight of acetone was added with stirring,
An infrared fluorescent organic pigment was obtained. To this, John Krill 61
(Manufactured by Johnson Polymer; acrylic-styrene resin,
10 parts by weight of solid content (30% by weight) and 15 parts by weight of water were added, and the mixture was mixed and dispersed in a ball mill for 3 hours to prepare an ink composition. The ink composition thus obtained was bar-code printed on a single Japanese paper divided into a portion having a reflectance of 70% of 800 nm infrared light and a portion having a reflectance of 5% with an inkjet printer.

Example 3 Acrylic modified silica sol dispersion (manufactured by Nippon Shokubai Co .; acrylic modified silica sol, solid content 20% by weight, particle size 30 n)
m) 100 parts by weight of IR-140 (manufactured by Kodak Laboratories Chemicals; polymethine dye, absorption wavelength peak: 826 nm, emission wavelength peak: 870)
(nm) 0.1 part by weight dissolved in 5 parts by weight of dimethyl sulfoxide was added with stirring to obtain an infrared fluorescent organic pigment. To this, 10 parts by weight of John Cryl 61 (manufactured by Johnson Polymer Co .; acrylic-styrene resin, solid content 30% by weight) and 15 parts by weight of water were added, and dispersed by a ball mill for 3 hours to give an ink composition. Prepared. The ink composition thus obtained was bar-code printed on a single Japanese paper divided into a portion having a reflectance of 800 nm infrared light of 60% and a portion having a reflectance of 3% by an inkjet printer. .

Comparative Example 1 1 part by weight of Rhodamine B (manufactured by Sumitomo Chemical Co., Ltd.), 100 parts by weight of water, 7 parts by weight of glycerin, and 3 parts by weight of ethylene glycol were stirred and mixed, and the ink composition was passed through a 1-micron filter. The thing was prepared. Then, the ink composition thus obtained was used to print on paper with an inkjet printer.

Comparative Example 2 IR820B (manufactured by Nippon Kayaku Co., Ltd .; polymethine dye, absorption wavelength peak: 820 nm, emission wavelength peak: 900)
nm) 0.15 parts by weight dissolved in 5 parts by weight of acetone, and a solution of 30 parts by weight of John Kryl 61 (manufactured by Johnson Polymer; acrylic-styrene resin, solid content 30% by weight) and 90 parts by weight of water. An ink composition was prepared by adding to the mixed solution while mixing. The ink composition thus obtained was used in an ink jet printer 8
Bar code printing was performed on one piece of Japanese paper divided into a portion where the reflectance of 00 nm infrared light was 70% and a portion where the reflectance was 5%.

Comparative Example 3 IR140 (Kodak Laboratories Chemicals;
Polymethine dye, peak of absorption wavelength: 826 nm, peak of emission wavelength: 870 nm) 0.05 part by weight was dissolved in 5 parts by weight of dimethyl sulfoxide to prepare a solution of Johncryl 61 (manufactured by Johnson Polymer; An ink composition was prepared by adding 30 parts by weight of acrylic-styrene resin (solid content 30% by weight) and 90 parts by weight of water while mixing and mixing. The ink composition thus obtained,
Using an inkjet printer, bar code printing was performed on a piece of Japanese paper divided into a portion having a reflectance of 60% of 800 nm infrared light and a portion having a reflectance of 3%.

Comparative Example 4 Inorganic phosphor LiNd _0.5 Yb _0.5 P ₄ O ₁₂ 8 parts by weight,
6 parts by weight of John Cryl 61 (manufactured by Johnson Polymer Co .; acrylic-styrene resin, solid content 30% by weight) and water 4
0 parts by weight were dispersed with a ball mill to prepare an ink composition. The ink composition thus obtained was bar-code printed on a single Japanese paper divided into a 70% portion and a 5% portion having a reflectance of 800 nm infrared light using an inkjet printer. .

The ink compositions and printed materials obtained in Example 1 and Comparative Example 1 were tested for storage stability, light resistance, bleeding property, re-dissolving property and transfer property by the following methods. In this Example and Comparative Example, an inkjet printer manufactured by Hitachi, Ltd .; GX-PA (nozzle aperture: 80 μm) was used as the inkjet printer.
Printing was performed.

<Storage stability> Each ink composition was treated at 50 ° C.
Stored in a constant temperature bath for 100 hours and examined the settling of the fluorescent pigment. When there is no settling (○), when there is settling (x)
Was evaluated.

<Light resistance> Each printed matter was irradiated with a fade meter for 1 hour, and the discoloration was visually observed. When there was no discoloration, it was evaluated as (◯), and when discoloration was evaluated as (x). .

<Bleeding property> The bleeding of the printed surface of each printed matter is observed. When there is no bleeding (○), when there is bleeding (x)
Was evaluated.

<Resolubility> Each ink composition was dropped onto a PET film, dried and solidified in a greenhouse for 24 hours, and alkaline water having a pH of 11 was dropped onto the PET film to redisperse (○), redispersion. Those not evaluated were evaluated as (x).

<Transfer characteristics> 20 sheets of each printed matter were superposed, a weight of 5 kg was applied to the printed matter, and the sheets were stored in a constant temperature bath at 30 ° C. for 600 hours. Those not transferred (◯) and those transferred (x)
And Table 1 below shows the results.

[0059]

The emission spectra of the printed surfaces of the prints obtained in Examples 2 and 3 and Comparative Examples 2 and 3 were measured using a spectrum measuring device manufactured by Unisoku. 2 and 3
2 shows the result, FIG. 2 shows the emission spectrum of the printed surface of the printed matter obtained in Example 2 and Comparative Example 2, and FIG. 3 is the printed matter obtained in Example 3 and Comparative Example 3. The emission spectrum of the printed surface is shown. 2 to 3
As is clear from the above, the infrared fluorescent dye used as the raw material is shifted to the long wavelength side by about 10 nm, but it is understood that the original properties of the infrared fluorescent dye are retained.

Next, regarding the bar code printing of the Japanese papers obtained in Examples 2 to 3 and Comparative Examples 2 to 4, the reflection output of the base and the output of the infrared fluorescent mark of the bar code. Was measured under the condition of high-speed reading of 4 m / sec with the detector shown in FIG. In this measurement, the reflected output at a reflectance of 50% is C ₀ , the output of the infrared fluorescent mark at a reflectance of 50% is C _1, and the infrared fluorescent light at the reflectance of 10% is shown. When the mark output was C ₂ , the ratio of C ₀ and C _{1 and} the ratio of C ₂ and C ₁ were measured.

Further, each bar code was read for 100 samples, and when the read rate was 95% or more, it was evaluated as (◯), and when it was less than 95%, it was evaluated as (x). Further, the printed matter was visually observed, and the case of bleeding was evaluated as (x), and the case of not bleeding was evaluated as (◯). In addition, the printed matter is 100 under a 5000 lux fluorescent lamp.
Measure the output after storage for a period of time and check the output maintenance rate. If the output maintenance rate is 70% or more (○), 70%
The light resistance was evaluated by setting the case of less than (X). Table 2 below
Is the result.

[0063]

[0064]

As is clear from Table 1 above, Example 1
The ink composition using the fluorescent organic pigment obtained in 1. has good dispersion stability, and the ink composition using the fluorescent organic pigment obtained in Example 1 is a comparative example. No bleeding, light resistance and water resistance are better than those printed and printed with the ink composition using the fluorescent dye of No. 1, and according to the present invention, there is no bleeding, dispersion stability, light resistance It can be seen that a fluorescent ink composition having excellent water resistance can be obtained.

Further, as is clear from Table 2 above, the infrared fluorescent mark (Examples 2 and 3) comprising the bar code printed on the Japanese paper according to the present invention was printed on the conventional Japanese paper. In comparison with the infrared fluorescent mark (Comparative Examples 2 to 4) composed of a bar code, the infrared fluorescent mark according to the present invention has a good readability without bleeding. -A stable, high-concentration infrared fluorescent mark that is not affected by dirt on ink or ink bleeding, and is also less affected by the base of the mark target. I know there is.

Further, according to the present invention, a bar printed on Japanese paper is used.
Infrared fluorescent mark consisting of code (Examples 2 and 3)
Indicates that, compared with the infrared fluorescent mark made of the inorganic phosphor of Comparative Example 4, good reading is possible without causing an erroneous operation even at high speed reading, and that the storage stability is good. .

[Brief description of drawings]

FIG. 1 is a schematic explanatory view showing an example of a reader for detecting infrared fluorescence.

FIG. 2 is an emission spectrum of a printed surface of printed materials obtained in Example 2 and Comparative Example 2.

FIG. 3 is an emission spectrum of a printed surface of printed materials obtained in Example 3 and Comparative Example 3.

Claims (5)

[Claims] 1. A fluorescent ink composition which contains water-dispersible colloidal silica having a resin component on its surface and exhibits fluorescence in the visible light region. 2. An infrared fluorescent ink composition containing water-dispersible colloidal silica having a resin component on its surface, absorbing infrared light having a wavelength of 700 nm or more, and emitting light in the infrared region. 3. A fluorescent mark containing water-dispersible colloidal silica having a resin component on its surface and exhibiting fluorescence in the visible light region. 4. An infrared fluorescent mark containing water-dispersible colloidal silica having a resin component on its surface, absorbing infrared light having a wavelength of 700 nm or more, and emitting light in the infrared region. 5. The rise time of 10 to 90% of the maximum emission power when the infrared fluorescent mark is irradiated with infrared light is 10.
The infrared fluorescent mark according to claim 4, which is within μsec.