JP4487090B2 - Luminous printed matter with authenticity discrimination - Google Patents

Description

  The present invention is a printed matter comprising a multicolor light emitting portion whose emission color changes in at least two colors or more depending on the wavelength in the ultraviolet region and a substance that absorbs a part of the ultraviolet wavelength, and at least partially overlapping, and is irradiated with visible light In particular, the present invention relates to a light-emitting printed material capable of determining authenticity in which the light emission color or the light-emitting shape of the printed material changes at the time of ultraviolet long-wave light irradiation, ultraviolet short-wave light irradiation, or ultraviolet long-short wavelength irradiation.

  Precious printed matter such as banknotes, securities, cards and tolls, and certificates that authenticate individuals such as driver's licenses, passports and insurance cards are always equipped with new anti-counterfeiting technology in order not to be counterfeited or tampered with by a third party. There is a demand for a true / false discrimination method that can determine whether the product is genuine.

  Among them, there are many authenticity determination methods using functional materials with special light emission and magnetism such as phosphors and magnetic materials, and these apply functional materials to printed matter, and these light emission in mechanical inspection and sensory inspection As a factor for determining the strength and presence or absence of magnetism, authenticity is determined.

  When using the characteristics of the functional material as an authenticity determination element, if the quality of the authentic product is not stable, it may be determined as a counterfeit product even if it is an authentic product in mechanical inspection or sensory inspection. In addition to the need for strict quality control over the entire process, the production of functional materials often involves special manufacturing equipment and complicated manufacturing processes. In general, the manufacture of a valuable product to which these authenticity determination elements are added requires a great deal of labor for the manufacturer as compared with the production of other products.

  Based on the above, valuable prints and certificates with authenticity determination elements are advanced prints that are difficult for counterfeiters to forge, and the manufacture methods are not complicated and easy for manufacturers to manage. Therefore, there is a demand for a technique that makes it easy for a user to determine authenticity.

  As an example of the anti-counterfeiting technology using the functional material, there is a printed matter using a phosphor that emits ultraviolet rays and emits light in the visible region. The printed matter is irradiated with ultraviolet rays, and whether or not the phosphor emits light is true. Many methods for discriminating false are proposed. Since the phosphor emission has different excitation characteristics, emission color, emission intensity, etc. depending on the type, it is used as a judgment element to distinguish counterfeit products from genuine products in mechanical inspections and sensory inspections using the differences. Yes. In the past, UV-excited phosphors were generally treated with the light emission color as a visual factor and the light emission intensity of the phosphor as a judgment factor in mechanical inspections. In order to cope with this, it is expected to include as many complex discrimination elements as possible, such as a fluorescence image, fluorescence intensity, afterglow intensity, and emission color, as plural / different kinds of authenticity discrimination elements.

  On the other hand, certain substances have a function of absorbing or reflecting a certain wavelength of ultraviolet rays (having a wavelength of less than 400 nm). Typical examples of the inorganic ultraviolet shielding material include zinc oxide, titanium oxide, cerium oxide, iron oxide and the like, and have high ultraviolet absorption characteristics particularly in the ultraviolet shortwave region (about 200 nm to 300 nm). In addition, all organic compounds containing halogen, carbonyl group, benzene ring, unsaturated group, etc. have a characteristic of absorbing ultraviolet rays, but salicylic acid type absorbers, benzophenone type ultraviolet absorbers, benzotriazole type ultraviolet rays Typical examples include absorbers and cyanoacrylate-based ultraviolet absorbers, and benzotriazole-based ultraviolet absorbers are known to have remarkable absorption characteristics even in the ultraviolet long-wave region (wavelength 400 nm to 300 nm). . Polyurethane resin, polyurea resin, polyamide resin, polyester resin, polycarbonate resin, aminoaldehyde resin, melamine resin, polystyrene resin, acrylic resin, styrene acrylic copolymer, gelatin, polyvinyl alcohol, etc. have a short wavelength range in the ultraviolet region. It is especially known for its absorption characteristics. In particular, acrylic resin is used as a filter for cutting ultraviolet shortwaves in an optical measuring instrument.

  Among the conventional examples that combine these ultraviolet light-absorbing substances and phosphors excited by ultraviolet light, as a security that can determine authenticity, a transparent film that absorbs or reflects ultraviolet light is applied to a transparent film. There has been proposed a securities in which latent information is printed in a transparent state using ink containing a fluorescent material on information that can be falsely identified. This is because when the printed surface printed with ink containing fluorescent material is irradiated with ultraviolet light, the ink emits light and information can be confirmed, but conversely, the ink is irradiated with ultraviolet light through the back side of the printed surface, that is, the film. In such a case, information cannot be confirmed because the film blocks ultraviolet rays (see, for example, Patent Document 1). This is an example in which the manufacturer's labor is the same as in the past, and the user can easily determine the authenticity of the difference between two types of fluorescent images and fluorescent emission intensity on the front and back of the film using a single light source.

  By the way, phosphors having excitation characteristics with respect to ultraviolet rays are roughly classified into phosphors having high excitation characteristics for ultraviolet shortwaves and phosphors having high excitation characteristics for ultraviolet longwaves.

  A general fluorescent print is one that is used for authenticity discrimination by checking the emission color and emission intensity using a phosphor excited by ultraviolet long waves, but a wide variety of phosphors are sold, In addition to the fact that it is relatively easy to obtain a phosphor with the same characteristics as an intrinsic phosphor, the fluorescent color can be confirmed with a black light or LED, making it easy to manufacture and authenticate. Therefore, it is easy to be counterfeited by a third party, and at present, the anti-counterfeiting power is already being lost.

  In addition, as for the phosphor of ultraviolet short wave excitation, the phosphor itself is less than the phosphor of ultraviolet long wave excitation, and in addition to being slightly difficult to obtain, a device for confirming the light emission is a mercury lamp, xenon lamp, Or, since germicidal lamps are special, there is a problem in that it is difficult to distinguish between authenticity and authenticity, although the anti-counterfeiting effect is higher than that of ultraviolet long-wave excitation phosphors.

  As described above, phosphors of ultraviolet long-wave excitation and ultraviolet short-wave excitation each have a relative problem, and in order to solve this problem, it is difficult to forge like ultraviolet short-wave excitation phosphors. On the other hand, there has been a demand for a phosphor that can be easily confirmed, such as an ultraviolet long wave excitation phosphor, and that can be discriminated with high accuracy in a strict confirmation, and a phosphor printed material thereof.

  In order to solve these technical problems, a polychromatic phosphor combining an ultraviolet short wave excitation phosphor and an ultraviolet long wave excitation phosphor has been proposed. As a specific example at the present time, it has been proposed to create a dichroic phosphor whose emission color changes between ultraviolet short wave irradiation and ultraviolet long wave irradiation (see, for example, Patent Document 2).

  Fluorescent ink whose emission color changes with ultraviolet shortwave and ultraviolet longwave can compensate for the problems of the conventional fluorescent ink. By mixing phosphors with high ultraviolet shortwave excitation characteristics and phosphors with high ultraviolet longwave excitation characteristics, The emission color changes depending on the irradiation wavelength. Since it is possible to change the color of ultraviolet longwave and ultraviolet shortwave by changing the phosphors to be mixed, forgery is difficult compared to conventional single color phosphors. In addition, since the emission color changes between ultraviolet shortwave and ultraviolet longwave, it is a phosphor that can be confirmed according to the security level, such as ultraviolet longwave for simple visual inspection and ultraviolet shortwave for strict mechanical detection. is there.

  In addition, many phosphors with ultraviolet shortwave excitation have some light emission even with ultraviolet longwave ultraviolet rays, and even forgers who have only ultraviolet longwave irradiation devices such as black light, the emission color at the time of ultraviolet shortwave excitation can be reduced. There was a case where it gave an idea. However, it is impossible to imagine the emission color in the ultraviolet shortwave because the light emission of the phosphor having high ultraviolet longwave excitation characteristics conceals the light emission of the phosphor having high ultraviolet shortwave excitation characteristics during ultraviolet longwave irradiation. From the above, the dichroic phosphor is an excellent phosphor in terms of preventing counterfeiting as compared with conventional phosphors, and is currently being applied to various products.

  Currently, the French 500 franc banknote is well known for printed matter that uses dichroic phosphors, which emits red when irradiated with ultraviolet shortwave, emits green when irradiated with ultraviolet longwave, There is a feature that the emission color of the entire phosphor printed portion is changed by irradiation with ultraviolet longwave and ultraviolet shortwave.

  One example of simply using this dichroic fluorescent ink and ultraviolet absorber with reference to the prior art is an ink that emits different fluorescence at two wavelengths on a transparent film that absorbs or reflects ultraviolet rays and blocks them. Fluorescent printed matter printed with can be considered. A specific fluorescent printed material will be described with reference to FIGS. FIG. 12 is a cross-sectional view of the fluorescent printed material.

  As a configuration of the fluorescent printed matter, a dichroic fluorescent printed portion printed on two parts of a transparent film (5) that absorbs or reflects ultraviolet rays and blocks different fluorescence at two wavelengths. In order to improve the visibility of meaningful information such as patterns and characters under visible light, except for the dichroic fluorescent printing part (6) It can be set as the structure coat | covered with the normal ink which has reflectivity.

  The transparent film (5) uses a pet film excellent in printability and processability from among substrates that do not transmit light with a wavelength of 300 nm or less, and the two-color luminescent ink used for fluorescent prints is an RB type (254 nm). Ink red light emission, 365 nm blue light emission) is used.

  FIG. 13A shows an example of light emission when the dichroic phosphor printing unit (6) is irradiated with ultraviolet light (7) from the printing surface. In this case, since all the wavelengths irradiated to the dichroic phosphor printing portion reach, both 254 nm and 365 nm emission colors appear, but the emission at 254 nm excitation, which has a higher emission intensity, mainly becomes the visual observation of the observer. In the confirmation, it is observed as red luminescence.

  FIG. 13B shows an example of light emission when the dichroic phosphor printing unit (6) is irradiated with ultraviolet light (7) from the back side of the printing surface through the transparent film (5). In this case, since the wavelength of 300 nm or less is absorbed by the film, in this case, the wavelength reaching the phosphor printing portion is limited to the long wave of ultraviolet rays, and the emission color at the time of excitation at 365 nm mainly becomes the In the confirmation, it is observed as blue luminescence.

  In the above example, a dichroic fluorescent ink and an ultraviolet absorber are simply combined. However, it has been proposed to use this dichroic fluorescent ink to change not only the luminescent color but also the luminescent site. A specific example is a printed material in which a visible light absorbing layer that absorbs fluorescence emission is printed on a base material, and a fluorescent image layer is printed thereon with inks that emit different fluorescence at two wavelengths. Fluorescent image formations that can authenticate authenticity are obtained by irradiating excitation light with different wavelengths and changing the color to two colors, and then absorbing the emitted light by the visible light absorbing layer, and changing the emission color and emission site. (See, for example, Patent Document 3).

JP 2001-18515 A JP-A-10-251570 Japanese Patent Laid-Open No. 10-250214

  In the example in which the dichroic phosphor and the ultraviolet absorbing material are simply combined, the color of the entire area to which the phosphor is applied is changed, although the emission colors on the front and back of the film are different. If the dichroic phosphor is used, the entire surface of the dichroic phosphor is coated with an ultraviolet absorbing material, so that the light emission on the entire dichroic phosphor printing portion changes, and the fluorescent printing portion is partially covered. There was a problem that the color could not be changed.

  Further, as disclosed in Japanese Patent Application Laid-Open No. 10-250214, when different materials are irradiated with different excitation light to emit different colors of ultraviolet shortwave and ultraviolet longwave, and a material that absorbs light emission is arranged on the lower surface, as in the present invention. It is possible to change the light emission color and the light emission site depending on the wavelength.

  However, since a material that absorbs fluorescent light is printed with a colored pigment such as a colored paint or ink, there is a possibility that the visible light absorbing layer can be visually confirmed during visible light observation. If the visible light absorbing layer can be visually confirmed, a shape in which light emission changes from the shape of the visible light absorbing layer can be imagined, and it becomes easy to forge. Furthermore, if the objective is to completely remove the emission color at the time of UV excitation by the visible light absorption layer, the formed material is prepared because the hue of the visible absorption layer must be finely adjusted according to the emission color of the phosphor. Requires technology and labor for production. In addition, the luminous intensity of the illuminant increases or decreases in proportion to the amount of UV irradiation, whereas the color density of the absorbing layer is constant, that is, the absorbing layer has a very high color density to absorb strong light. However, in the case of weak light, the concentration of the absorbing layer must be lowered, so that the conditions for completely absorbing light emission are limited only to a certain amount of ultraviolet irradiation. From this, it seems that a desired effect can be obtained only when a certain amount of ultraviolet irradiation is applied. In addition, since the emission intensity and reflection density depend greatly on the observation environment, even when the UV irradiation amount is the expected value, observation is performed in an environment where visible light is inserted, and in an environment where no visible light is inserted. If you do, the effect is likely to change greatly. From this, even if the desired effect can be obtained only by observation under a specific condition, the light emitting layer or the absorption layer may be easily confirmed visually when the condition is not satisfied. .

  An object of the present invention is to solve the above-described problems. Specifically, after printing is performed with ink that emits fluorescence that is different between the long wavelength and the short wavelength in the ultraviolet region, a part of the printed portion is obtained. In an extremely simple procedure, such as overprinting with ink containing an ultraviolet absorber, the emission color or emission site changes in a complex manner when irradiated with visible light, irradiated with ultraviolet longwave light, irradiated with ultraviolet shortwave light, or irradiated with ultraviolet shortwave light. It is an object of the present invention to provide a luminescent printed material that can be determined by machine discrimination or visual observation.

  The luminescent printed matter of the present invention is a luminescent printed matter having a true / false discriminating region on a substrate, and the surface of the true / false discriminating region is irradiated with ultraviolet rays of different wavelengths, respectively, A multicolor light-emitting part having the characteristic that the emission color changes by changing the light emission intensity is formed, and has a characteristic of absorbing a part of the ultraviolet wavelength that excites the multicolor light-emitting part on the multicolor light-emitting part. It is characterized in that an overprint portion is formed by overlapping a substance having a part of a multicolor light emitting portion.

  Further, in the luminescent printed matter of the present invention, the multicolor light emitting part is formed by laminating a plurality of fluorescent inks having different excitation wavelengths and emission wavelengths, or a plurality of different excitation wavelengths and emission wavelengths. It is formed with the ink which mixed the fluorescent substance of this.

  According to the present invention, it is possible to obtain a light-emitting printed matter in which the light emission color and the light-emitting site vary depending on the irradiation wavelength of ultraviolet rays. In addition to being able to use multiple colors of luminescence intensity as an element for authenticity discrimination, it is also possible to recognize changes in the luminescent part as an image and add it as a discrimination element. There will be a dramatic increase in the choices of the true / false discrimination elements. In addition, since the emission color and the emission site change according to each irradiation wavelength, it is possible for users who have only black light to check ultraviolet long-wave light emission. By performing short-wave irradiation, more sophisticated and complicated authentication can be performed.

  On the other hand, since the fluorescent mixture can adjust not only the combination of the phosphors but also various color combinations and emission intensity depending on the mixing ratio of the phosphors, it is not possible for a counterfeiter to reproduce the change in emission color. In addition to being difficult as compared with conventional monochromatic phosphors, it is necessary to achieve a higher technical level to reproduce the effect of simultaneously changing the light emitting part according to the wavelength.

  In addition, conventionally, it is difficult for a manufacturer to obtain a printed matter using metamerism that changes color when light of a different wavelength is applied while applying the same color of light of a certain wavelength. In order to make them together, extremely high skill was required for toning, and labor for preparation was also required. However, according to the present invention, as long as the fluorescent ink and the ultraviolet absorber are used, it is possible to guarantee at least complete color matching at the time of ultraviolet long-wave irradiation and color difference at the time of ultraviolet short-wave irradiation. Furthermore, on the luminescent ink whose emission color changes in two colors according to the wavelength in the ultraviolet region, a resin or the like that absorbs a part of the ultraviolet wavelength is printed so that it partially overlaps, In order to produce printed matter, high skill for color matching is not required, and labor for production is unnecessary, and the work can be easily performed.

  In Example 2, the dichroic phosphor is made solid with a dot percentage of 100% at 175 line, and a gradation scale in which the dot percentage gradually changes from 5% to 100% at 175 line using an ultraviolet absorber for this. After overprinting and simultaneously irradiating short ultraviolet rays and long ultraviolet rays, the hue continuously changed from red to blue as the dot area ratio increased. In this way, various gradations can be expressed by intentionally changing the halftone dot percentage of the ultraviolet absorber.

  As described above, the present invention proposes a printed matter that changes in accordance with the emission color that simultaneously achieves high anti-counterfeiting effects and manufacturing stability and the ultraviolet wavelength irradiated by the light emitting portion.

  In practicing the invention, a case where a fluorescent printed material is prepared using an ink prepared using a dichroic fluorescent pigment will be described. Four types of dichroic fluorescent pigments are used: DE-RB, DE-RG, DE-GB, and DE-GR (manufactured by Nemoto Special Chemical). In addition to 20% dichroic fluorescent pigment and 80% varnish. As an external split, an oxidation polymerization type offset ink was prepared using a 3 roll mill containing 4% phthalocyanine blue and 1% desiccant. As shown in FIG. 1, these are simple inks, but when excited with ultraviolet light at 254 nm, the main emission peak is in the green or red wavelength region, and when excited with ultraviolet light at 365 nm, the main ink peak. The light-emitting peak has a dichroic characteristic that changes in the blue, green, and red wavelength regions.

  FIG. 2 shows a spectroscopic measurement of a change in spectral intensity when 254 nm and 365 nm ultraviolet rays are irradiated to a dichroic fluorescent pigment of DE-RB type (red emission when excited at 254 nm, blue emission when excited at 365 nm). It is. When irradiated with 254 nm, there is a peak near 440 nm as in the case of 365 nm irradiation. However, since the intensity of the light emission peak near 610 nm is relatively strong compared to this light emission peak, blue light emission is not recognized by visual confirmation. , Recognized as red light emission. In addition, since there is no emission peak near 610 nm when irradiated with 365 nm, it is visually recognized as blue emission. In addition, this ink became a colored ink which was recognized as a light blue under visible light observation although the fluorescence emission was slightly reduced by adding phthalocyanine blue.

  FIG. 3 is a plan view of the fluorescent printed material according to the present invention, and FIG. 4 is a cross-sectional view of the fluorescent printed material according to the present invention. FIG. 5 shows a dichroic phosphor printed portion and an overprint portion of the fluorescent printed material divided into each plate surface. Actually, after the dichroic phosphor is printed on the substrate, the dichroic fluorescent material is printed. An ultraviolet absorber is completely superimposed on a part of the printed body (overprint portion) and printed at a desired position. The number of lines on the printing plate for the dichroic phosphor printing portion and the printing plate for the overprinting portion is 175 lines in consideration of the ink transfer property and the light emission intensity. In addition, the dot percentage of all printing portions is 100%. It was.

  In this example, since the offset printing method was selected, a non-fluorescent offset coated paper containing no fluorescent brightening agent was used as the substrate. In consideration of the transferability of offset fluorescent ink, it is appropriate to use coated paper. However, the fluorescent whitening agent contained in the coated paper or processed base paper may interfere with the fluorescence emission of the ink. For this reason, it is desirable to use a coated paper that does not contain an optical brightener.

  However, by using a coated paper containing a fluorescent brightening agent, the emission intensity emitted from the coated paper itself and the emission intensity of the phosphor when irradiated with ultraviolet longwave or ultraviolet shortwave are adjusted to the same level, as if ultraviolet rays Printed material with a configuration in which the fluorescent light emitting part is almost inconspicuous when irradiated with long waves or ultraviolet short waves, the emission color emitted by the coated paper itself using coated paper containing a fluorescent whitening agent, and fluorescence when irradiated with ultraviolet long waves and ultraviolet short waves Needless to say, the present invention also sufficiently lies in the form of simultaneously utilizing the fluorescence emission emitted from the coated paper itself and the effect of the present invention, such as a printed matter having a configuration in which the color of the body is different.

  In addition, the offset printing method was selected in this example, but when changing the balance between the emission intensity at the time of ultraviolet shortwave irradiation and the emission intensity at the time of ultraviolet longwave irradiation, the ultraviolet shortwave excitation type phosphor and the ultraviolet longwave excitation type were selected. It is appropriate to review the mixing ratio of the phosphors, and when the fluorescent printing part by offset printing is entirely lower than the light emission intensity desired by the user, a printing method that can easily obtain the pigment film thickness, for example, gravure It is desirable to select a printing method such as printing or screen printing.

  The dichroic fluorescent ink was prepared by preparing 20% of the RB type pigment for offset shown in FIG. 1 and 80% of the varnish, and adding 4% of phthalocyanine blue and 1% of the desiccant as an external ratio. A multicolor light emitting part was formed using ink. Further, as an ink containing an ultraviolet absorber used for overprinting, a general-purpose offset ink (DIC varnish new champion mat manufactured by DIC) was used. The UV absorption characteristics of this OP varnish are shown in FIG.

  The ultraviolet absorber to be used is not limited to this, and a function of absorbing or reflecting a part of a plurality of excitation wavelengths of the dichroic phosphor to inhibit light emission in a certain wavelength region of the dichroic fluorescent light emitting portion. Anything that constitutes In this example, a varnish containing an inorganic ultraviolet absorbing material having a strong absorption characteristic at 200 to 300 nm was selected for the purpose of suppressing light emission on the ultraviolet short wavelength side, but it is not particularly limited to this. It goes without saying that even if a material having a strong absorption characteristic on the long wave side is used, the change in the luminescent color and the luminescent part targeted by the present invention can be sufficiently achieved.

  As shown in FIG. 5, the overprint part needs to have a region overlapping the dichroic phosphor print part as shown in FIG. 5. It is appropriate in terms of obtaining the effect of changing the part.

  In addition, the ink for the overprint part needs to have a certain ultraviolet absorption property, but when considering the drying property and printability, the main components are acrylic resin, styrene resin, urethane resin. Etc. are desirable.

  However, it is not appropriate to absorb the light on the ultraviolet shortwave side and the ultraviolet longwave side substantially evenly in order to produce the color change remarkably. Further, when there is a limit to the thickness of the film that can be applied, or when long-term durability is required for the product, it is appropriate to blend an inorganic ultraviolet absorber such as titanium oxide or zinc oxide. In addition, since it is desirable not to inhibit the color of the fluorescent ink printed part when visible light is observed, it is preferable that the color is colorless.

  In this embodiment, the smoothness of the paper used is Beck smoothness of about 600 seconds, which is slightly lower for coated paper, and the glossiness (75 ° gloss_JIS_P8142_Z8741) is also as low as 55%, resulting in dichroism. The phosphor printed part was also 55% matte, so the matte OP varnish alone was used for overprinting. However, the gloss of the overprinted part depends on the glossiness of the paper and the dichroic phosphor printed part. It is desirable to adjust. Specifically, it is possible to adjust the glossiness of the overprint portion by mixing a matte tone and glossy varnish. By changing the blending ratio, the glossiness of 55% to 75% is obtained at 75 ° gloss. For glossiness of 60 °, glossiness of 40% to 67% can be adjusted. Therefore, when considering the visibility of fluorescent prints and overprints under visible light, matte OP varnish It is desirable that the glossy OP varnish is mixed so as to match the glossiness of the paper and the phosphor printed portion so that the overprint portion is not as conspicuous as possible.

  Both the dichroic phosphor printing part and the overprinting part were applied with dichroic fluorescent ink by a 175 line offset method and dried, and then overprinted using the OP varnish.

  FIG. 6 is a diagram showing a detection state when the fluorescent printed material is irradiated with ultraviolet rays having different wavelengths. Under normal visible light shown in (a), both the fluorescent print portion and the overprint portion are recognized as light blue. When irradiated with the ultraviolet long wave (365 nm) shown in (b), the entire mark fluoresces blue, and when irradiated with the ultraviolet short wave (254 nm) shown in (c), the overprint portion does not emit light, and other dichroic phosphors are added. Only the area changed to red light emission. In addition, when the ultraviolet long and short wave (200 to 400 nm) irradiation shown in (d) was simultaneously performed, the overprint portion emitted blue light, and the other areas emitted red light.

  As an example of a combination of a polychromatic phosphor and an ultraviolet absorber, an embodiment of the present invention in the case where the halftone dot% of the ultraviolet absorber is changed and the hue is gradually changed from red to blue will be described with reference to the drawings.

  The dichroic phosphor is made solid with a dot percentage of 100% at 175 line, and an ultraviolet absorber is used for this, and overprinting of gradation scale is performed with the dot percentage gradually changing from 5% to 100% at 175 line. . FIG. 8 is a plan view of the fluorescent printed material according to the present invention. FIG. 9A shows a dichroic fluorescent printing portion of the luminescent printed material in FIG. 8, and FIG. 9B shows an overprint portion for printing with an ultraviolet absorber. Actually, a multicolor fluorescent part is formed on a substrate by printing with a dichroic phosphor, and then an ultraviolet absorber is completely overprinted at a desired position on the multicolor fluorescent part. is there.

  The ink used was the same as in Example 1, and pleochroic fluorescent printing was used by adding phthalocyanine blue to the RB type dichroic fluorescent ink, and the UV absorber used for overprinting was the same as in Example 1. Offset ink (OP varnish new champion mat made by DIC) was used. As in Example 1, a non-fluorescent offset coated paper was used as the substrate, and printing was performed with an offset printer.

  FIG. 10 shows the ultraviolet absorption characteristics of the printed matter of the ultraviolet absorber alone, and it can be confirmed that the amount of absorbed ultraviolet rays increases as the dot area ratio of the ultraviolet absorber increases. In addition, in the ultraviolet long wave region (365 nm), there is almost no difference in absorption characteristics due to the halftone dot area ratio of the ultraviolet absorber, but in the ultraviolet short wave region (254 nm), absorption due to the halftone dot area ratio of the ultraviolet absorber. It can be seen that the difference in characteristics opens greatly.

  FIG. 11 is a diagram showing the effect of the fluorescent printed material in Example 2 by the change in hue. The dot percentage of the overprinted portion by the ultraviolet absorber with respect to the phosphor is shown, (a) is a 0% site, (b) is a 50% site, and (c) is 100% of the ultraviolet short wave irradiation time. 2 shows the fluorescence emission distribution and the fluorescence emission distribution during ultraviolet long-wave irradiation. As the halftone dot area ratio of the ultraviolet absorber increases, the red emission intensity during ultraviolet shortwave irradiation decreases, but the blue emission intensity does not change during ultraviolet longwave irradiation.

  Even in visual confirmation, blue light emission is predominant during ultraviolet long-wave irradiation, and the density of blue hardly changes in the dot percentage of 5% to 100% of the overprint part, and during ultraviolet short-wave irradiation, Although red light emission is dominant, light emission was suppressed as the halftone dot percentage of the overprint portion increased. When ultraviolet shortwave and ultraviolet longwave were irradiated simultaneously, the hue gradually changed from red to blue as the halftone dot area ratio increased, and the hue gradually changed from red to blue.

  In this embodiment, the hue is adjusted by the dot area of the ultraviolet absorber, but it goes without saying that the same effect can be obtained by changing the coating thickness of the ultraviolet absorber.

  As described above, a combination of the pleochroic phosphor and the ultraviolet absorber gave a fluorescent printed material effective for preventing counterfeiting and authenticity discrimination in which the fluorescent color and the hue of the fluorescent site change continuously.

The emission peaks of the dichroic fluorescent ink when excited at 254 nm and excited at 365 nm are shown. The spectral intensity change of DE-RB type is shown. The top view of the fluorescent printed matter of this invention is shown. Sectional drawing of the fluorescent printed matter of this invention is shown. (A) shows the dichroic fluorescent printing part of the fluorescent printed matter in Example 1 of this invention, (b) shows an overprint part. It is a figure which shows the observation state of the fluorescent printed matter of this invention, (a) at the time of visible light observation, (b) at the time of ultraviolet-ray long wave (365 nm) irradiation, (c) at the time of ultraviolet-ray short wave (254 nm) irradiation, (d) These are figures which show the time of ultraviolet long and short wave (200-400 nm) irradiation. It shows the UV absorption characteristics of OP varnish. The top view of the fluorescent printed matter in Example 2 of this invention is shown. (A) shows the dichroic fluorescent printing part of the fluorescent printed matter in Example 2 of this invention, (b) shows an overprint part. The ultraviolet absorption characteristic of the overprint part in Example 2 of this invention is shown. FIG. 6 shows changes in spectral intensity of an overprint portion in Example 2 of the present invention, where (a) is a part with 0% halftone dot, (b) is a part with halftone dot 50%, and (c) is a part with halftone dot 100%. FIG. Sectional drawing of the fluorescent printed matter of a prior art is shown. (A) shows an example of light emission when the phosphor printing part is irradiated with ultraviolet light from the printing surface, and (b) shows an example of light emission when the phosphor printing part is irradiated with ultraviolet light through the film from the back side of the printing surface.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Base material 2 Normal printing part 3 Multicolor light emission part 4 Overprint part 5 Transparent film 6 Dichroism fluorescent printing part 7 Ultraviolet light

Claims (2)

A light-emitting printed material having a true / false discrimination region on a substrate,
By irradiating the authenticity discrimination region with ultraviolet light in the long wave region and / or ultraviolet light in the short wave region , a multicolor light emitting part having a characteristic that the emission color changes by changing the emission wavelength and / or emission intensity is formed. And
A substance having a characteristic of selectively absorbing ultraviolet light in a short wave region or a substance having a characteristic of selectively absorbing ultraviolet light in a long wave region among the ultraviolet light that excites the multicolor light emitting unit on the multicolor light emitting unit. and Ri Na said overprinted portion was overlapped by a portion of the multi-color light-emitting portion is formed,
The visible color under visible light, the visible image when irradiated with ultraviolet longwave light, the visible image when irradiated with ultraviolet shortwave light, and the visible image when irradiated with ultraviolet shortwave light are different from each other in the luminescent color and / or luminescent site that is visible. A luminescent printed matter capable of authenticating authenticity, wherein authenticity determination is performed . The overprint part formed on the multi-color light emitting part forms a gradation due to a continuous change in the dot area ratio within a range of 5 to 100% of the dot area ratio,
When viewed with the ultraviolet long-wave light and ultraviolet short-wave light being simultaneously irradiated, it is visually recognized as a light-emitting color continuously changed from the emission color at the time of ultraviolet long-wave light irradiation to the emission color at the time of ultraviolet short-wave light irradiation. The luminescent printed matter capable of authenticating authenticity according to claim 1.

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