JP2695523B2 - Printed material suitable for copy protection - Google Patents

Description

[Detailed Description of the Invention] [Field of industrial application] The present invention relates to a technique for preventing copying of securities, various certificates, important documents, and the like.

[Conventional technology]

With the remarkable progress of copying machines, color copying machines have become widespread, and the risk of counterfeiting such as securities, various certificates, important documents, etc. being copied in a format that closely resembles the real thing is increasing.

Conventionally, a patent application has been filed (Patent Application Publication No. 58-38188) in which a latent image appears when a latent image is printed by utilizing the density of a pattern and reproduced by a color copier or the like. Since the latent image is recognized even with the naked eye due to the use of the density of the image, the invention has been devised to overprint the pattern and camouflage the latent image (Patent Application Publication No. 64-5835). However, in order to camouflage with this method, it was necessary to add one color, which was troublesome and costly.

[Problems to be solved by the invention]

This invention provides securities, various certificates, important documents, etc. with a function to prevent forgery by a copying machine, so that latent images such as characters, symbols, and patterns are formed on printed matter by patterns consisting of halftone dots and lines. The purpose is to obtain a printed matter that makes it obvious that it is a counterfeit when it is printed in one color using offset, gravure, flexo or screen printing, and this printed matter is copied with a color copier etc. .

[Means for solving the problem]

A latent image consisting of a pattern of halftone dots or lines having a predetermined number of lines that cannot be resolved by a copying machine and a halftone dot or parallel lines having a predetermined number of lines that can be resolved by a copying machine on the paper surface. Simultaneously prints the background consisting of patterns such as a single color, and a camouflage pattern of uniform density existing across the latent image area and the background area has a large area ratio against a background of uniform density other than the pattern. When applied so that the camouflage pattern existing in the latent image area becomes equal to the number of lines of the pattern such as halftone dots or lines forming the latent image, and the camouflage pattern existing in the background area is The camouflage pattern is applied by the pattern of halftone dots or lines so that the number of lines of the pattern of halftone dots or lines forming the background is equal.

[Action]

By producing the printed matter configured as described above, it is possible to apply the copy prevention function to the printed matter of one color, and the alignment such as printing is unnecessary.

Further, on the paper surface, a latent image formed of a pattern of halftone dots or lines having a predetermined number of lines that is not resolved by a copying machine,
A background consisting of a pattern of halftone dots or lines with a predetermined number of lines that can be resolved by a copier is printed simultaneously in one color, and a uniform density existing across the latent image area and the background area When the camouflage pattern is applied to a background having a uniform density other than the pattern so as to have a large area ratio, the camouflage pattern existing in the latent image area is a pattern of halftone dots or lines forming the latent image. The camouflage pattern should be equal to the number of lines, and the camouflage pattern existing in the background area should be equal to the number of lines of the pattern such as halftone dots or lines forming the background. Since the pattern is applied, only the camouflage pattern can be identified with the naked eye by the area ratio, that is, the density contrast. The background consisting of patterns such as halftone dots or lines having a predetermined number of lines that can be resolved by a copying machine is reproduced as it is, while a background of a predetermined number of lines that is not resolved by a copying machine is reproduced. The latent image composed of patterns such as halftone dots or lines is not reproduced, and the camouflage pattern with a large area ratio existing in the background area is reproduced as it is, whereas it exists in the latent image area. Even if the camouflage pattern has a large area ratio, the camouflage pattern is hardly reproduced, and the latent image is more clearly discriminated than the latent image obtained by copying the conventional camouflage-patterned printed matter.

〔Example〕

As shown in the conceptual diagram of Fig. 1, the number of screen lines is 200 lines / i, which forms a latent image of chrysanthemum flowers by one-color offset printing.
nch, halftone dot 10% pattern (1) and screen frequency 200 lines / inch, halftone dot 15% pattern (3), and background screen 100 l
A pattern (2) with ines / inch and a dot percentage of 10% and a pattern with a screen frequency of 100 lines / inch and a dot percentage of 15% (3 ') were printed.

As shown in FIG. 2, when the printed matter is viewed with the naked eye,
The area ratio composed of patterns (3) and (3 ') is 15
The portion of% has a higher density than the portion of which the area ratio composed of the patterns (1) and (2) is 10%, and thus is recognized as a concentric pattern.

As shown in Fig. 3, a copy of this printed material (the copy machines used are Fuji Xerox 5055: monochrome copier and Canon Laser Copier CLC1: color copier),
A pattern with a certain number of lines that can be resolved by a copying machine (2)
The background region composed of (3 ') and (3') is reproduced as it is, whereas the chrysanthemum flower composed of patterns (1) and (3) having a predetermined number of lines that is not resolved by the copying machine. The latent image pattern area was hardly reproduced not only in the area (1) having a small area ratio but also in the area (3) having a large area ratio, and it was obvious that the area was a duplicate.

〔The invention's effect〕

The present invention provides a printed matter having a function of preventing copying by a copier or the like by printing in one color.

In order to camouflage the latent image, a camouflage pattern is provided without adding another color so that the latent image cannot be discerned by the naked eye.

According to the present invention, securities capable of preventing copying by a copying machine, various certificates, important documents, and the like can be produced, thereby enhancing the forgery prevention effect.

[Brief description of the drawings]

FIG. 1 is a diagram showing an outline of the printed matter of the embodiment.
Shows the case where the printed matter of the example is seen with the naked eye. FIG.
A copy when this printed matter is copied is shown. 1 ... Screen lines 200 lines / inch, halftone dot percentage 1
0% area 2 …… Screen frequency 100 lines / inch, halftone dot percentage 1
0% area 3 ... Screen frequency 200 lines / inch, halftone dot percentage 1
5% area 3 '... screen frequency 100 lines / inch, halftone dot area 15% area

Claims (1)

(57) [Claims] 1. A latent image composed of a pattern of halftone dots or lines having a predetermined number of lines which is not resolved by a copying machine and a predetermined number of lines which is resolved by a copying machine on a paper surface. A background consisting of patterns such as halftone dots or lines is simultaneously printed in one color, and a camouflage pattern of uniform density existing across the latent image area and the background area is used as a background of uniform density other than the pattern. On the other hand, the camouflage pattern existing in the latent image area should be equal to the number of lines of the dots or lines forming the latent image in the latent image area, and in the background area. The camouflage pattern is applied by the pattern of halftone dots or lines so that the existing camouflage pattern has the same number of lines as the pattern of halftone dots or lines forming the background. Printed materials.