JPH10264496A - Nonduplicative printed matter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent forgery using a color copy machine and to recognize forgery easily and instantaneously using a color filter by forming a printed matter using two kinds of ink developing a substantially identical color and having a specified emission wavelengths and a specified difference of reflectance. SOLUTION: A printed matter is formed using two kinds of ink developing a substantially identical color and having an emission wavelength in the vicinity of 600 nm, and a difference of reflectance of 10% or above. One of two kinds of ink has a reflection peak in the wavelength region of 430-450 nm and an absorption peak in the wavelength region of 490-510 nm while the other ink has a reflection peak in the wavelength region of absorption peak and an absorption peak in the wavelength region of 560-570 nm wherein the difference of reflectance is 10% or more between the absorption peaks. When such a printed matter is color copied, variation of density appears in the printed matter due to the shift of hue between two kinds of ink and a copy can be distinguished easily from an original printed matter.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a copy-prevention printed matter which makes it difficult to forge a printed matter such as securities, certificates, entrance tickets or various tickets by copying with a color copying machine or the like.

[0002]

2. Description of the Related Art The accuracy of recent copying machines has been remarkably improved, and there is a risk that securities and passports are easily copied or forged, especially with the spread of the latest electrophotographic system.
Therefore, conventionally, various methods have been tried as methods for preventing forgery using a color copying machine. As a typical example of a printed matter for preventing copying, a printed matter to which the principle of metamerism (equal color) is applied is well known (for example, Japanese Patent Publication No. 60-58711 and Japanese Patent Publication No. 61-37636). Etc.), the digitalization of copiers has progressed, and the resolution and color correction functions have been significantly improved. Therefore, the above-described forgery prevention method is not sufficient, and the forgery prevention using a further color copier is not sufficient. The emergence of a measure was strongly desired.

[0003]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and prevents forgery caused by copying using a color copying machine or the like, and easily and immediately by viewing through a filter. It is intended to provide a printed material capable of recognizing forgery.

[0004]

In order to solve the above-mentioned problems, the present invention provides a method for producing color images having substantially the same color and having an emission wavelength of 6 nm.
In the vicinity of 00 nm, a printed material using two kinds of inks having a difference in reflectance of 10% or more, wherein one of the two kinds of inks has a reflection peak in a wavelength range of 430 nm to 450 nm, The other ink has an absorption peak in the wavelength range of 490 nm to 510 nm, and the other ink has a reflection peak in the wavelength range of the absorption peak, an absorption peak in the wavelength range of 560 nm to 570 nm, and a reflectance at the absorption peak. And a difference of 10% or more.

[0005] Further, it is characterized in that the presence or absence of forgery of the printed matter is identified using a specific color filter.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION The copy-prevention printed matter of the present invention is formed by using two kinds of inks having different spectral reflectances in a specific wavelength range, but having the same emission wavelength range, on a base material. It is a printed matter printed, and in the printed matter, these inks have the same color-developing region and have similar hues, so that the difference in color tone cannot be recognized by the naked eye, but when this printed matter is copied by a color copying machine, The copy has a density change due to the hue shift of the two kinds of inks, and it can be seen that the copy is a copy. In addition, when the printed matter is viewed with the naked eye using a specific color filter, a density difference occurs partially, and the presence or absence of forgery can be immediately identified.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below based on embodiments, but the present invention is not limited to these embodiments.

One of the two types of inks used in the present embodiment is prepared by mixing a daylight fluorescent pigment [AP-506: Nippon Soda Co., Ltd.] having a difference between the absorption wavelength and the emission wavelength of 100 nm with a vehicle. It is a combined ink
Hereinafter, the ink is referred to as a wavelength conversion ink. The other ink of the two types is obtained by mixing two types of commercially available daylight fluorescent pigments to form an ink. In the present embodiment, orange and magenta are used as examples. FIG. 3 shows spectral reflectance curves of the wavelength conversion ink and the daylight fluorescent ink.

In the present embodiment, examples of the base material include various papers and films, such as high quality paper, coated paper, and security paper.

FIG. 1 shows a printed material obtained by alternately printing patterns on a substrate (1) using a wavelength conversion ink (2) and a daylight fluorescent ink (3) having the same color as the ink. It is.

As shown in the spectral reflectance curve of FIG. 3, the obtained printed matter has the emission wavelengths of the wavelength conversion ink and the daylight fluorescent ink near 600 nm. Is difficult to distinguish with the naked eye, but in the wavelength range of 490 nm to 510 nm,
The wavelength conversion ink shows an absorption peak, the daylight fluorescent ink shows a reflection peak, and the reflectance curve in the above-mentioned wavelength region shows a diametrically opposite peak, and the reflectance of both peaks is 10%.
When copying with a color copying machine (manufactured by Canon: Digital full-color copying machine CLC-800),
As shown in FIG. 2, the design part (2) printed with the wavelength conversion ink is copied darkly, and the design part (3) printed with the daylight fluorescent ink is copied very lightly, resulting in a difference in density and being a duplicate. I understand. Since a plurality of inks having different densities between the printed matter and the copy obtained by copying the printed matter by the color copying machine are printed adjacent to each other, the operation is performed using the color correction mechanism provided in the color copying machine. Can not be reproduced.

In the printed matter of this embodiment, two types of inks having substantially the same color are printed adjacent to each other.
Although it is hard to distinguish the symbols with the naked eye, a specific color filter (for example, Fuji Filter SP-4M, BPB
By using -50), as shown in FIG. 2, only the design portion (2) printed with the wavelength conversion ink looks dark, and the design portion (3) printed with the daylight fluorescent ink appears very thin. And the presence or absence of forgery can be easily identified from the difference between the two contrasts. This is because, as shown in FIG. 3, the reflectances of the two inks are significantly different in the wavelength range of 490 nm to 510 nm, and a difference in density occurs when viewed using a color filter containing a large amount of transmission components around 500 nm. Be identified.

Further, in the printed matter of this embodiment, since two kinds of inks, ie, the wavelength conversion ink and the daylight fluorescent ink, which have the same appearance, are printed adjacent to each other, it is difficult to distinguish the patterns. However, by applying ultraviolet light to the printed matter, the wavelength conversion ink has a higher luminance than the daylight fluorescent ink, so that only the design part printed with the wavelength conversion ink emits strong light, so that the presence or absence of forgery can be easily identified. .

[0014]

The copy-prevented printed matter of the present invention is a printed matter in which two kinds of inks having substantially the same color development, an emission wavelength of about 600 nm, and a difference in reflectance of 10% or more are printed adjacently. The printed matter is hardly distinguished by the naked eye, but by copying with a color copying machine, a density difference occurs in the design of the copied matter, and it is understood that the printed matter is a copied matter.
In addition, when the printed matter is viewed with the naked eye using a specific color filter, a part of the design is emphasized darkly and appears to be embossed, which is effective for authenticity discrimination.

[Brief description of the drawings]

FIG. 1 is a diagram showing a configuration of a printed matter of the present invention.

[Figure 2] Copy

FIG. 3 shows spectral reflectance curves of a wavelength conversion ink and a daylight fluorescent ink.

[Explanation of symbols]

 1 printing substrate 2 wavelength conversion ink 3 daylight fluorescent ink

Claims (2)

[Claims] 1. The color development is substantially the same and the emission wavelength is 6
A printed matter using two kinds of inks having a reflectance difference of 10% or more around 00 nm, wherein one of the two kinds of inks has a reflection peak at 430 nm to 450 nm, and a reflection peak at 490 nm to 510 nm. The other ink has a reflection peak in the wavelength range of the absorption peak, and has a reflection peak in the wavelength range of 560 nm to 5 nm.
An anti-copying printed matter having an absorption peak at 70 nm and a difference of 10% or more from the reflectance at the absorption peak. 2. The copy-protected printed matter according to claim 1, wherein the presence or absence of forgery of the printed matter is identified using a specific color filter.