JP2009137088A - Printed matter and printing method using infrared absorptive ink - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve the problem that a designedness is deteriorated, although determination of authenticity by a machine is possible, when printing is made with infrared absorptive ink, since the ink itself is dark. <P>SOLUTION: First printing is made on a printing surface of a base 1 by using the infrared absorptive ink which contains an infrared absorptive pigment showing an L value of 50 or more as brightness. After a first infrared absorptive printed area 2 is formed by the first printing, second printing is made over the first infrared absorptive printed area 2 by using infrared absorptive ink showing likewise the L value of 50 or more as brightness. The substrate of the base 1 is not hidden and transmittance becomes excellent since the brightness of the infrared absorptive ink used in every printing is high. Besides, a second infrared absorptive printed area 4 printed in superposition is visually recognizable in itself as a pattern and thus the design property is enhanced. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a printed matter having security information for preventing counterfeiting of banknotes, securities, passports, etc., or performing authenticity determination, and a printing method using infrared absorbing ink for such printed matter. About.

Conventionally, as a printing technique used for preventing counterfeiting of securities and authenticity determination, a convex region printed on the base material surface of the authenticity determination medium is provided, and the convex region is raised from the surface of the base material. Are known. (For example, refer to Patent Document 1). Furthermore, this prior art also enables authenticity determination using a device by using infrared absorbing ink for printing the convex region.
Japanese Patent Laying-Open No. 2005-219356 (Page 4-5, FIGS. 1-4)

  In the above prior art, when the same color ink as the base material is used for the convex region, or when transparent ink, transparent resin, etc. are used, the convex region is observed when tilted from the vertical direction with respect to the authenticity determination medium. The latent image is confirmed by being divided and visually recognized. However, the printing in this case is only a latent image, and when the naked eye is observed from the vertical direction with respect to the authenticity determination medium, the convex region cannot be divided and visually recognized, and the design property as a printed matter is improved. Is not planned at all. Further, as a matter of course, when a pigment ink having a color forming property or a transparent resin is used, the authenticity cannot be determined by a device such as an infrared camera.

  On the other hand, in the prior art, it is necessary to use infrared absorbing ink when authenticity determination is performed by a device such as an infrared camera. In this case, the prior art uses an ink with low brightness such as carbon black (see paragraphs 0033 and 0034 of Patent Document 1). However, an infrared absorbing ink such as carbon black can only be visually recognized as black by the naked eye, and has a property of concealing the base on the surface of the substrate. If printing is performed over a wide range using such dark ink, the surface of the substrate becomes blackish as a whole, and the design is greatly reduced. Therefore, the prior art infrared absorbing ink can usually be used only for the part where the authenticity is determined by the instrument. In addition, even if a black ink such as carbon black is overprinted to form the convex region, the black ink is only on the black printed area, and it is not possible to observe the pattern etc. with the naked eye. .

  Therefore, the present invention enables the authenticity determination by the device, and the printing area for that purpose has high brightness so as not to cover the background, and the printing area can be visually recognized with the naked eye even under natural light or illumination light. This is an issue.

  As a result of intensive research, the inventors of the present invention have performed printing using an infrared absorbing ink containing an infrared absorbing pigment exhibiting an L value of 50 or more as a single unit of lightness, and overprinted this at least twice. Thus, the overprinted portion can be utilized as a pattern that can be visually recognized with the naked eye, and a printed matter and a printing method that can be used to determine the authenticity of the device even when the infrared absorbing ink is not overlapped have been invented. .

  That is, the printed matter of the present invention is a first infrared absorption printing region that is printed on the printing surface of the medium using an infrared absorbing ink containing a first infrared absorbing pigment that exhibits an L value of 50 or more as brightness. And the second infrared-absorbing ink containing an infrared-absorbing pigment having an L value of 50 or more as lightness, and the second printed on the printed surface so as to overlap with at least the first infrared-absorbing printing area. And an infrared absorption printing area. The first infrared absorbing ink and the second infrared absorbing ink may have the same brightness at an L value of 50 or more, or may have different brightness.

  The infrared absorbing ink (first or second infrared absorbing ink) used for printing in the present invention is one in which the infrared absorbing pigment contained therein has higher brightness than conventionally known carbon black. On the other hand, even if such an infrared absorbing pigment having a high brightness is contained in an amount sufficient for device determination, the brightness of the infrared absorbing ink as a whole is not lowered.

  For this reason, in the first infrared absorption region where the first infrared absorption ink having high brightness is printed only once (one layer), the background of the printing surface can be seen through well, so printing can be performed over a wide range. Even if it is done, the original design of the base does not deteriorate. Furthermore, when the second infrared absorbing ink is printed on top of it, the second infrared absorbing region where the ink is superimposed can be raised to a level that can be distinguished from the other, thereby improving the design of the printed matter. Can now. Further, in the authenticity determination using the device, the first infrared absorption region in which the first infrared absorption ink is printed only once, and the second infrared absorption ink on which the second infrared absorption ink is printed twice overlap the second infrared absorption region. Since both the infrared absorption regions can be determined, it is possible to print the security information over a wide range of the printing surface without deteriorating the apparent design.

  The second infrared absorption printing area was formed by overlapping the first layer of the first infrared absorption ink formed on the printing surface in the first infrared absorption printing area and the first layer. By overlapping with the second layer of the second infrared absorbing ink, it is visible as a predetermined pattern under visible light. Since the predetermined pattern includes everything that can be expressed by printing, such as characters, figures, symbols, designs, etc., the range of design variations can be expanded accordingly.

  The inventors of the present invention have found the following optimum ranges as the compositions of the first and second infrared absorbing inks. That is, it is an infrared absorbing ink in which an infrared absorbing pigment is mixed with a resin in a mass ratio of 1: 0.03 to 1: 0.30.

  By mixing the infrared absorbing pigment with the resin (vehicle) within the above range, the infrared absorbing effect (inherent infrared spectrum) that can be determined by the instrument can be exhibited, and good transparency of the groundwork is achieved. Obtainable.

  Preferably, the first and second infrared absorbing inks contain antimony-doped tin oxide as an infrared absorbing pigment.

  Antimony-doped tin oxide is an infrared absorbing pigment that is not black like carbon black, is not white like tin oxide, and has an L value of 50 or more as a simple substance. For this reason, when the ink is overprinted, the moderate dullness of the contained antimony-doped tin oxide makes the second infrared absorption region stand out as a pattern or the like, thereby improving the visual design. As a result, it is possible to obtain a printed matter that does not become blackish.

  The inventors of the present invention provide a printing method for obtaining the printed matter. In the printing method, on the printing surface of the medium, after forming a first infrared absorbing printing region printed using a first infrared absorbing ink containing an infrared absorbing pigment having an L value of 50 or more as brightness, Using a second infrared absorbing ink containing an infrared absorbing pigment exhibiting an L value of 50 or more as lightness, a second infrared absorbing print area printed over the at least first infrared absorbing print area on the printing surface To form. At this time, the second infrared absorption printing region is overlapped on the first layer of the first infrared absorption ink formed on the printing surface in the first infrared absorption printing region and the first layer. By overlapping with the second layer of the formed second infrared absorbing ink, it is formed as a pattern that is visible under visible light.

  According to the printing method of the present invention, it is possible to enhance the apparent design of the printed material while providing the printed material with security that allows the device to determine authenticity / authenticity.

  The remarkable effect of the present invention is that it has succeeded in improving the design of printed matter with the infrared absorbing ink itself, which could not be achieved with a conventionally known infrared absorbing ink such as carbon black. Therefore, the present invention can greatly expand the range of designs for passports, banknotes, securities, etc. that require security information. In particular, since it can be easily implemented as a printed matter indispensable for people's lives, such as passports and banknotes, it can greatly contribute to future industrial development.

  The best mode for carrying out the present invention will be described below. The best mode of the present invention can be obtained by printing using an infrared absorbing ink in which an infrared absorbing pigment is antimony tin (antimony-doped tin oxide). Hereinafter, specific examples will be described.

〔Example〕
As one Example, each material (1)-(4) of infrared absorption ink used for printing, a substance name, and its mass are shown below. The infrared absorbing ink is obtained by mixing the material (3) in a vehicle in which the following materials (1) and (2) are mixed, and kneading the mixture with a propeller type mixer, for example.

[Materials used]
(1) Resin: Polyester resin ... 100 (g)
(2) Solvent: 1: 1 mixture of methyl ethyl ketone and toluene ... 100 (g)
(3) Infrared absorbing pigment: antimony-doped tin oxide 10 (g)

[Mass ratio]
As described above, the mixing ratio (mass ratio) of resin: infrared absorbing pigment in the infrared absorbing ink used in the examples is 1: 0.1.

[Printing method]
Printing was performed with a small gravure printing machine using the infrared ink prepared as an example. First, a plate having a plate depth of 30 μm is printed on a substrate (quality paper: J, manufactured by Fuji Xerox Co., Ltd.) for the first time, dried, and then another plate having a plate depth of 30 μm using the same infrared absorbing ink. The second printing was performed. In any case, the film thickness was about 4 μm.

[Printed matter]
FIG. 1 is a diagram illustrating an example of a printed matter P obtained by the above printing method. This printed matter P was printed on substantially the entire printing surface of the substrate 1 at the first time using the above infrared absorbing ink, and partially printed at the second time using the same infrared absorbing ink. Is.

  As shown in a relatively light gray color in FIG. 1, the portion where only the first printing is performed becomes the first infrared absorption region 2. Although only shown in gray here, the actual first infrared absorption region 2 sufficiently transmits the printing surface of the substrate 1 of the printed matter P, and does not conceal the base of the printing surface.

  Further, as shown by a relatively dark gray color in FIG. 1, the portion where the infrared absorbing ink overlaps in the second printing is a second infrared absorbing region 4. The second infrared absorption region 4 has a lightness difference from other portions (first infrared absorption region 2) due to the overlap of the ink, and can be distinguished and visually recognized with the naked eye. Although shown here in dark gray, the second infrared absorption region 4 also has a high lightness so as not to conceal the background of the printing surface. As shown in the figure, the second infrared absorption region 4 can be formed as a pattern such as “KP”. Note that the design is not limited to characters, but may be anything such as graphics, symbols, designs, etc. that can be expressed by printing.

  FIG. 2 is a diagram showing the above printing method in the order of steps. Hereinafter, the printing method will be described in order.

[Step 1: First printing]
In FIG. 2, (A): The gravure printing of the 1st time is performed to the substantially whole area of the printing surface of the base material 1 using the infrared rays absorption ink quoted as one Example. The first printed portion is formed as the first infrared absorption region 2 as described above. In addition, although the base material 1 is shown here in a shape after cutting, the actual base material 1 has a peripheral portion before cutting.

[Step 2: First printing]
In FIG. 2, (B): After drying, the second gravure printing is performed using the same infrared absorbing ink. In addition, since the part (the part used as the 2nd infrared absorption area | region 4) which performs the 2nd printing uses the same infrared absorption ink, the brightness when it sees alone is the same as the 1st infrared absorption area 2 is there.

  In FIG. 3, (C): At this time, by forming a predetermined pattern (for example, characters such as “KP”) on the plate, the pattern can be expressed by the second infrared absorption region 4 as described above. it can.

[Optimum mass ratio range]
In addition, the range of the following mass ratio is made optimal from the result of the inventors' separate verification.
Resin: Solvent: Infrared absorbing pigment = 1: 1: 0.03 ~
1: 1: 0.30

[Reasons for selecting mass range]
First, the reason for selecting the lower limit is that when the mass ratio of the infrared absorbing pigment is less than 0.03, the infrared absorptivity becomes low, which makes it unsuitable for determination using ordinary equipment.
The reason for selecting the upper limit is that when the mass ratio of the infrared absorbing pigment exceeds 0.30, the transparency of the undercoat is lowered after printing, and the printability becomes poor as the physical properties of the ink.

[Lightness of infrared absorbing pigment: L value]
Next, the brightness of the infrared absorbing pigment (antimony-doped tin oxide) used in one example will be verified. Here, the L value is used as the brightness. The L value is a value represented by 0 to 100, and the value becomes smaller as the lightness is lower, and conversely, the value becomes larger as the lightness is higher. When lightness is measured for a black pigment, its L value should theoretically be 0 (close to 0). However, since the pigment is actually inked and printed on the medium (base material 1) to measure the brightness, the L value may not match the theoretical value as a result of being affected by the hue of the base material 1 or the resin. is there.

〔Measuring method〕
(1) The materials are mixed at the above-described mass ratio to produce the same infrared absorbing ink.

(2) Bar coater No. is applied to plain paper (J, manufactured by Fuji Xerox Co., Ltd., L value 94 ± 5). The ink was applied once using 125 and dried.

(3) L value of the area | region which apply | coated the infrared absorption pigment was measured using the spectrophotometer (U-4000 self-recording spectrophotometer, Hitachi make). The wavelength range used was 800-350 nm, light source D65, viewing angle 2 degrees.
(4) As a result of measurement, 68 ± 5 was obtained as the L value of antimony-doped tin oxide.

[Comparative pigment]
The inventors of the present invention measured the L value of carbon black and tin oxide in the same manner as comparison objects with antimony-doped tin oxide when selecting an appropriate range of L value as the brightness of the infrared absorbing pigment. It was. The results are as follows.

Carbon black: 26 ± 5
Tin oxide: 91 ± 5

  Although not specifically shown here, the inventors of the present invention also performed various verifications on other pigments. The results are as follows.

[Comparative Pigment 1]
When a pigment having an L value of less than 50 was used, the ink was too dark and the ink look dull, resulting in poor base transparency.

[Comparative Pigment 2]
When a pigment having an L value exceeding 85 was used, it was too bright and the second infrared absorption region 4 could not be distinguished with the naked eye and could not be visually recognized as a pattern.

[L value appropriate range]
From the above measurement results, the lightness of the infrared absorbing pigment used in the present invention has an appropriate L value in the range of 50 to 85. In particular, the inventors of the present invention optimally use an infrared absorbing pigment having an L value of 60 to 80 within the above range.

[Equipment judgment]
Next, the printed material P of one embodiment was determined by the device.
FIG. 3 is a diagram showing an outline of device determination for the printed matter P. As shown in FIG. 3A shows an image obtained by photographing the printed matter P with an infrared camera. Further, (B) in FIG. 3 is a cross-sectional view showing a laminated structure of the printed matter P.

  In FIG. 3, (A): As described above, the infrared absorbing ink used for printing has a brightness of L value 50 or more, and when this is photographed with an infrared camera, it exhibits sufficient infrared absorbing properties. It was confirmed that At this time, it can be seen that the second infrared absorption region 4 has higher infrared absorptivity than the first infrared absorption region 2, and the image of that portion is darker.

  In FIG. 3, (B): When viewed in a laminated structure, in the range where the first infrared absorption region 2 is exposed toward the infrared absorption camera (reference numeral M) (A0 in the drawing), It can be seen that only one layer (first layer) of infrared absorbing ink is formed. On the other hand, in the range where the second infrared absorption region 4 is exposed to the device M (A1 in the figure), the infrared absorption ink is two layers (first layer and second layer) on the substrate 1. It can be seen that they are overlapped.

  Accordingly, when the whole is photographed by the infrared absorption camera (M), the image becomes relatively thin due to the infrared absorption effect of only one layer in the range A0, but the image becomes darker by the infrared absorption effect of two layers in the range 1. You can see it. Note that when the sensitivity of the device is actually low, the range A0 may appear as bright as the infrared reflective ink. However, even in this case, the range A1 is visible as an image. Is fully applicable.

  The printed matter P mentioned in one embodiment is only a sample, but as is clear from the properties of the printed matter P, the printed matter obtained by the above printing method is obtained under visible light (natural light or indoor illumination light). When the naked eye observation is performed, the second infrared absorption region can be visually recognized as a pattern, and thereby the design of the printed matter can be improved. Moreover, since good transparency can be exhibited without concealing the base as a whole, there is no problem in terms of design even if printing is performed using an infrared absorbing ink over substantially the entire printing surface.

  Moreover, since the obtained printed matter can also be determined by a device, the security of banknotes, securities, passports, etc. can be greatly improved.

  The present invention is not limited to the above-described embodiment, and various applications are possible. In the embodiment, the first infrared absorption region 2 is formed over substantially the entire printing surface. However, the first infrared absorption region 2 may be formed only on a part of the printing surface. In addition, the first infrared absorption region 2 is made into a shape such as a character or a figure by the first printing, and the second printing is performed over a wide range on the first infrared absorption region 2, resulting in a portion overlapping as the second infrared absorption region 4. A pattern may be formed.

  Further, in the example of the printed matter P described above, the infrared absorbing ink having a common material mixing ratio is used for the first printing and the second printing. However, the mixing ratio is different for each of the first printing and the second printing. You may use two types of infrared inks which are prepared separately. In this case, for example, the lightness can be changed for each ink type by slightly changing the mixing ratio of the infrared absorbing pigment for each ink type.

  If the brightness is secured to the extent that the pattern can be expressed by overlapping the infrared absorbing ink, and within the range not departing from the object of the present invention, a colorant such as a pearl pigment or a fluorescent pigment is mixed with the infrared absorbing ink. May be.

It is a figure which shows an example of the printed matter obtained by the printing method using infrared rays absorption ink. It is the figure which showed the printing method in process order. It is a figure which shows the outline | summary of the apparatus determination with respect to printed matter.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Base material 2 1st infrared absorption area | region 4 2nd infrared absorption area | region P Printed material

Claims (5)

On the printing surface of the medium, a first infrared-absorbing print area printed using a first infrared-absorbing ink containing an infrared-absorbing pigment exhibiting an L value of 50 or more as lightness;
Using the second infrared absorbing ink containing an infrared absorbing pigment exhibiting an L value of 50 or more as lightness, the second infrared ray printed on at least the first infrared absorbing printing area on the printing surface. A printed matter having an absorption printing region. The printed matter according to claim 1,
The second infrared absorption printing area is
A first layer of the first infrared absorbing ink formed on the printing surface in the first infrared absorbing printing region, and the second infrared absorbing ink formed over the first layer. A printed matter that is visible as a predetermined pattern under visible light by being superimposed on the second layer. The printed matter according to claim 1 or 2,
In the first and second infrared absorbing inks,
The printed matter, wherein the infrared absorbing pigment is mixed with the resin in a mass ratio of 1: 0.03 to 1: 0.30. The printed matter according to any one of claims 1 to 3,
The first and second infrared absorbing inks are
A printed matter comprising antimony-doped tin oxide as the infrared absorbing pigment. On the printing surface of the medium, after forming a first infrared absorbing printing region printed using a first infrared absorbing ink containing an infrared absorbing pigment exhibiting an L value of 50 or more as brightness,
Second infrared absorption printing printed using at least the first infrared absorption printing region on the printing surface by using a second infrared absorption ink containing an infrared absorption pigment having an L value of 50 or more as brightness. By forming a region,
The second infrared absorbing printing area;
A first layer of the first infrared absorbing ink formed on the printing surface in the first infrared absorbing printing region, and the second infrared absorbing ink formed on the first layer. A printing method using an infrared absorbing ink, wherein the pattern is formed as a pattern visible under visible light by being superimposed on the second layer.