JPH06236129A - Uncopiable document - Google Patents

Abstract

PURPOSE:To provide the uncopiable document which is high in visibility and has an uncopiable area with high copying preventing performance. CONSTITUTION:The uncopiable area 2 is formed by printing a group of mesh points or lines as a background part, which is colored in a kind of purple, sepia, deep blue, etc., low in reflectivity in a wavelength range of 500-600nm and shaded in dotted pattern, slantingly to a read reference direction at an angle where moire is generated when the area is copied by a digital copying machine with the density closed to the resolution of it. Then image information is printed on a print layer 4. Consequently, when the document is copied, the uncopiable area 2 becomes blackish and the dotted pattern 3 is superposed on the image information to camouflage the information and generate the moire, and then the image information can not be read to keep secrecy sufficiently.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a non-copyable form in which image information becomes black and unreadable when a document is copied by a copying machine.

[0002]

2. Description of the Related Art In order to prevent leakage of confidential information, when a document is copied by a copying machine, the contents of the image information become black and unreadable, so that the information cannot be diffused. Are disclosed in JP-A-59-114566 and JP-B-1-54706.

The former structure is a form in which the copy protection area is printed in a sepia color, and shows a reflectance of 10% or less in a wavelength range of 600 nm or less. When this is copied, the portion of the print layer becomes black and the image information printed on the print layer becomes unreadable.

The latter structure is a form in which a solid printing layer and a pattern printing layer are overprinted on the front surface of the base and a solid printing layer is formed on the back surface.

[0005]

In the above-mentioned conventional structure and in the structure of Japanese Patent Laid-Open No. 59-114566, since the entire form has a reflectance of 10% or less, printing is performed on it. There is a problem that the content is difficult to read.

Further, the structure of Japanese Patent Publication No. 1-54706 has a problem that it is difficult to print because the reflection density is designated, and both sides must be printed a plurality of times, resulting in high cost.

Therefore, in order to eliminate such a problem,
The inventor of the present invention is composed of colors such as purple, sepia, and indigo that have a low reflectance in the wavelength range of 500 nm to 600 nm, and print with a dot pattern of 50 to 80% as a background. We have proposed a non-copyable form with a non-copyable area formed by printing.

The print layer of the non-copyable area of this form has a patchy light portion rather than the entire dark portion.
A reflectance of 10% or more is secured. Here, the one with low reflectance becomes black and the one with high reflectance becomes white. Therefore, the image information printed in the non-copyable area can be read due to the difference in reflectance. In the case of copying the form, however, it is generally difficult to read the characters for the following reason (details will be described later).
The sensitivity of the copying machine is low in the wavelength range of 500 nm or less and 600 nm or more. On the other hand, the purple system, the sepia system, the indigo system and the like have low reflectance in the wavelength range of 500 nm to 600 nm. Therefore, the non-copyable area of the copied form becomes dark as a whole. For this reason, the difference between the image information and the print layer in the copied product becomes small, and the dark spot pattern overlaps with the characters, resulting in camouflage, which makes the characters unreadable. .

By the way, even with such a construction, if the non-copyable area is printed with a lighter density, the printed layer does not become completely black when the copy is made by a digital copying machine, and the characters to be hidden are not printed. It becomes possible to determine. On the other hand, when the non-copyable area is printed with a darker density, there is a problem in that the visibility of characters deteriorates.

An object of the present invention is to eliminate the problems of the conventional structure.

[0011]

The present invention provides a 500 nm
(Nanometer) ~ 600nm color with low reflectance in purple, sepia, indigo, etc.
-80% dots or lines are printed as the background,
Further, in the same color, which has a non-copyable area formed by solid-printing a tint block, the dot or line group as the background portion has a density close to the resolution of the digital copying machine, and It is characterized in that the image is printed at an angle that causes moire by copying and is inclined with respect to the reading reference direction.

[0012]

The printing layer of the form does not have a thickened whole, but has a patchy light portion. Therefore, a reflectance of 10% or more can be secured, and as described later, the whole is made too dark. Even if it does not exist, a copy-preventing action occurs, so that the image information printed on the image can be easily read.

When the uncopyable area is copied, the image information printed on the uncopyable area cannot be read. Here, the principle of disabling copying of the print layer will be described.

Purple system (a), sepia system (b),
The indigo system (C) is 500 nm to 60 nm as shown in FIG.
The reflectance is low in the wavelength range of 0 nm and is 50 in the purple system.
The reflectance increases at 0 nm or less and 600 nm or more. Further, in the sepia system, the reflectance increases above 600 nm.
Furthermore, in the indigo system, the reflectance increases below 500 nm.
Here, the wavelength of the colored light is expressed by a unit nanometer (nm) with a fineness of 1 millionth of 1 mm, the visible region is 400 to 700 nm, and the one with low reflectance becomes black and the one with high reflectance is It becomes white.

On the other hand, the sensitivity of the copying machine is generally good in the vicinity of 550 nm as shown in the characteristic diagram of FIG. 5. For example, a color having a high reflectance in the wavelength range of 550 nm, such as yellow, is solid-printed, and When I copy, I drop out and the print layer is no longer copied. On the contrary, in the wavelength range (400 to 500 nm, 600 to 700 nm) at both ends of the visible region, the sensitivity of the photosensitive drum of the copying machine is not so good, and the color reflected at these wavelength ranges is black in the copying machine. I will end up.
Therefore, the wavelength region at both ends of the visible region (400-500n
The color of the printing layer having a high reflectance at m, 600 to 700 nm) is affected by the low sensitivity of the copying machine, exhibits a low reflectance over the entire visible wavelength range, and becomes a black color as a whole. .

Due to such characteristics, 500 nm to 600 n
Purple system, sepia system, which has low reflectance in the wavelength range of m,
When the indigo system is copied by a copier, it is less than 500nm and 60
Even if a high reflectance is shown at 0 nm or more, since the copying machine has a low sensitivity in this region, the copied material is not sensitive to the reflectance of the original and becomes dark. On the other hand, 500n
Since the reflectance is low in the wavelength range of m to 600 nm, the portion corresponding to the print layer of the copied form is blackened as a whole, and the difference in shade from the copied image information is reduced.
By the way, further, a spot pattern such as a tint block is darkened, overlaps with image information, and is camouflaged.

On the other hand, according to the present invention, an angle that causes moire (interference fringes) by copying with the digital copying machine the density of the dot or line group as the background portion, which is close to the resolution of the digital copying machine. It is inclined and printed.

That is, the digital copying machine has a characteristic that when it is tilted with respect to the reading reference direction, moire occurs on the copy paper side depending on the tilt direction.
Therefore, even if the non-copyable area is printed with an appropriate density so that the printed image information can be easily viewed, when the image is copied with a digital copier, the image information to be hidden is generated due to the occurrence of moire. In combination with the effect of the mottled pattern, it becomes unreadable.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment of the present invention will be described with reference to the accompanying drawings.

1 and 2 show a non-copyable form 1 according to the present invention.
The non-copyable area 2 is printed at a predetermined position on the non-copyable form 1.

The non-copyable area 2 is 500 nm to 60 nm.
As shown in an enlarged view in FIG. 3, it is made of colors such as purple, sepia, and indigo that have a low reflectance in the wavelength range of 0 nm. Is shaded by. This is 50 ~
Print 80% dots or lines as background 4.
Further, it is formed by solid-printing a tint block with the same color.

In the non-copyable area 2, the reflectance increases in the purple system at 500 nm or less and 600 nm or more. Further, in the sepia system, the reflectance increases above 600 nm. Furthermore, in the indigo system, the reflectance increases below 500 nm. Therefore, as shown in FIG.
At 0 to 500 nm and 600 to 700 nm, the sensitivity of the photosensitive drum of the copying machine is poor, and the colors reflected in the wavelength regions at both ends have little influence on the sensitivity of the copying machine. The reflectance becomes low and it becomes black.

Therefore, when printing is performed on the non-copyable area 2 with a printer, the characters can be distinguished from the non-copyable area 2 by the black print character and the difference in color tone due to each coloring, and the lighter part by the spot pattern 3. Is occurring.

On the other hand, when what is printed on the non-copyable area 2 is copied by a copying machine, the part of the non-copyable area 2 becomes black as a whole as described above, and further, due to the mottled pattern 3, a dark spot. The pattern will overlap with the image information and camouflage will be applied.

Further, the background portion 4 is printed at an angle which causes moire when copied by a digital copying machine and is inclined with respect to the reading reference direction. The angles are about 15 °, 20 ° and 75 °.

This relationship is shown in FIG. 6. When each dot is represented by o, the dots o are inclined at equal intervals n and at an angle θ with respect to the reading reference direction X. This angle θ is the above-mentioned angle.

Next, the inclination angle θ of the dots of the background portion 4 and
The relationship with the occurrence of moire will be explained.

As shown in FIG. 7, the digital copier 10
Is the reflected light irradiating the non-copyable form 1, which is the original G, with C
It is introduced into the image pickup device 10a such as a CD, photoelectrically converted, binarized based on an analog signal corresponding to the contrast of image information, and image information is copied based on this image signal. is there.

The resolution of such a digital copying machine is dramatically improved as compared with the conventional analog copying machine, but the reading pixels 20 in the image pickup device 10a of the CCD are read.
It is known that interference occurs depending on the overlapping of the dot and the dot of the document G, and moire occurs as shown in FIG.

Table 1 shows the results of the moire test conducted by the present applicant using a Canon color copying machine "Pixel Dio (CLC-500)".

[Table 1]

As is clear from this table, for example, 85
In the case of a line, a dot with a linear density of 30%, an inclination angle of 30
No, moire does not occur on the copy paper when copying.
However, it can be seen that moiré is clearly generated at the inclination angles of 15 °, 20 ° and 75 °.

Therefore, when printing is performed on the non-copyable area 2 with a printer, the characters can be distinguished from the non-copyable area 2 due to the difference in color tone due to the black print characters and the coloring, and the lighter part due to the mottle pattern 3. By producing the, the required reflectance can be secured and the printed characters can be easily read.

In the above construction, the background portion 4 is composed of dots, but it may be composed of a line group, and in this case as well, the background portion 4 is formed with an angle which causes moire by copying with a digital copying machine. , Tilt with respect to the reading reference direction.

In this way, the uncopyable area 2 is
In the wavelength range of m to 600 nm, it is made of a color of a purple system or the like having a low reflectance, and 50 to 80% of dots or lines are set as the background portion 4. Therefore, as described above, in the relation of the sensitivity of the copying machine, As a whole, it becomes darker, and due to the mottled pattern 3, the black mottled pattern overlaps with the characters to cause camouflage, which causes moire on the copy paper, making the characters unreadable. Become. Since the moire superimposes the concealing action, the image information cannot be read on the copy without making the copy-prohibited area 2 too dark. Therefore, it is possible to form a document with good visibility.

[0034]

The present invention, as described above, has the advantage of 500 nm.
Digitally copy the dots or lines that consist of purple, sepia, indigo, etc. colors with low reflectance in the wavelength range of up to 600 nm, and have a tint pattern such as tint block and background 4 The non-copyable area 2 is formed by printing at a density close to the resolution of the machine and at an angle that causes moire when copied by a digital copying machine, with an inclination with respect to the reading reference direction, and an image is formed on the print layer. Since the information is printed, in the copied state, the uncopyable area 2 is darkened and the mottled pattern 3 is formed.
Is overlapped with the image information, camouflage is applied, and due to the occurrence of moire, the image information cannot be read and confidentiality can be sufficiently maintained. Further, since the moire superimposes the concealing effect, the image information of the copy cannot be read and the original with good visibility can be created without making the copy-prohibited area 2 too dark. And so on.

[Brief description of drawings]

FIG. 1 is a plan view of a form-non-copyable form 1 according to the present invention.

FIG. 2 is a vertical sectional side view of a non-copyable form 1.

FIG. 3 is an enlarged view of an uncopyable area 2.

FIG. 4 is a graph showing the relationship between each wavelength of the purple system (a), the sepia system (b), and the indigo system (c) and the reflectance.

FIG. 5 is a characteristic diagram showing a relationship between wavelength and sensitivity of a copying machine.

FIG. 6 is an explanatory diagram showing a relationship between a reference direction X and a halftone dot inclination angle θ.

7 is a conceptual diagram showing the copying principle of the digital copying machine 10. FIG.

FIG. 8 is a plan view of a non-copyable area 2 showing the occurrence of moire.

[Explanation of symbols]

 1 non-copyable form 2 non-copyable area 3 speckled 4 background

Claims (1)

[Claims] 1. A color composed of a purple system, a sepia system, an indigo system or the like having a low reflectance in a wavelength range of 500 nm to 600 nm, 50 to 80% of dots or lines are printed as a background portion, and the same color is used. When a non-copyable area formed by solid-printing a copy-forgery-inhibited pattern is provided, the dot or line group serving as the background portion has a density close to the resolution of the digital copying machine and is copied by the digital copying machine. A non-copyable form characterized by being printed at an angle that causes moire due to an inclination with respect to the reading reference direction.