JP2990564B2 - Non-copyable form - Google Patents

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, when a document is copied by a copying machine, image information becomes black and cannot be read.

[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 image information become black and become illegible, preventing the spread of information. Are disclosed in JP-A-59-114566 and JP-B-1-54706.

The former configuration is a form in which a copy protection area is printed in a sepia color and has 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 this print layer becomes unreadable.

[0004] The latter configuration is a form in which a solid print layer and a pattern print layer are overprinted on the front surface of the base and a solid print layer is formed on the back surface.

[0005]

In the above-mentioned conventional configuration, in the configuration of Japanese Patent Application Laid-Open No. Sho 59-114566, the entire form has a reflectance of 10% or less. There is a problem that the contents are difficult to read.

Further, the configuration of Japanese Patent Publication No. 1-54706 has a problem that the reflection density is specified, so that printing is difficult and that both sides must be printed a plurality of times, which is expensive.

Therefore, in order to eliminate such a problem,
The inventor of the present invention prints a color such as a purple system, a sepia system, or an indigo system having a low reflectance in a wavelength range of 500 nm to 600 nm, and prints with a tint of 50 to 80% as a background. A non-copyable form with a non-copyable area formed by printing is proposed.

The printing layer in the non-copyable area of the form has a spot-like light portion instead of the entire dark portion.
A reflectance of 10% or more is secured. Here, the one with a low reflectance becomes black, and the one with a high reflectance becomes white. Therefore, the image information printed in the non-copyable area can be read by the difference in the reflectance. However, when such a form is copied, it is generally difficult to read the characters for the following reason (the details will be described later).
The sensitivity of the copying machine is low in a wavelength range of 500 nm or less and 600 nm or more. On the other hand, the reflectivity of the purple system, sepia system, indigo system, and the like is low in the wavelength range of 500 nm to 600 nm. Therefore, the non-copyable area of the copied form is darkened as a whole. For this reason, the copied image has a small difference in shading between the image information and the print layer, and the dark spotted pattern overlaps the character, causing camouflage and rendering the character unreadable. .

By the way, even in such a configuration, if a non-copyable area is printed with a lower density, the printed layer is not completely black when the digital image is copied with a digital copying machine, and characters to be concealed are not printed. It can be determined. On the other hand, if the non-copyable area is printed at a darker density, there is a problem that the visibility of the characters deteriorates.

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

[0011]

SUMMARY OF THE INVENTION The present invention provides a 500 nm
(Nanometer) It consists of colors such as purple system, sepia system and indigo system with low reflectance in the wavelength range of ~ 600 nm, and 50
~ 80% of dots or lines are printed as background,
Further, in the same color, provided with a non-copyable area formed by solid printing a copy-forgery-inhibited pattern, the dot or line group serving as the background is set to a density close to the resolution of the digital copying machine, and The printing is performed in such a manner that the copy is inclined at an angle at which a moiré is generated by the copying with respect to the reading reference direction.

[0012]

The printed layer of the form does not darken the whole, but has a patchy light portion. Therefore, a reflectance of 10% or more can be ensured. Even if the image information is not provided, a copy prevention effect is produced, so that the image information printed thereon can be easily read.

When the non-copyable area is copied, the image information printed on the non-copyable area cannot be read. Here, the principle of making it impossible to copy the printing layer will be described.

The purple system (a), the sepia system (b),
The indigo line (c) is, as shown in FIG.
The reflectance is low in the wavelength region of 0 nm, and 50% in the purple system.
The reflectance increases at 0 nm or less and 600 nm or more. In the sepia system, the reflectance increases at 600 nm or more.
Further, in the indigo system, the reflectance increases below 500 nm.
Here, the wavelength of the color light is expressed in a unit nanometer (nm) of 1/100 of 1 mm, the visible region is 400 to 700 nm, those with low reflectance become black, and those with high reflectance become black. It turns white.

On the other hand, as shown in the characteristic diagram of FIG. 5, the sensitivity of the copying machine is generally good near 550 nm. For example, a color having a high reflectance in the wavelength region of 550 nm, such as yellow, is printed by solid printing. Is copied out and the printed layer is not copied. Conversely, in the wavelength regions at both ends of the visible region (400 to 500 nm, 600 to 700 nm), the sensitivity of the photosensitive drum of the copying machine is not very good, and the color reflected in the wavelength regions at both ends is perceived as black by the copying machine. I will.
Therefore, the wavelength ranges at both ends of the visible region (400 to 500 n
m, 600 to 700 nmm), the color of the printing layer having a high reflectance is affected by the low sensitivity of the copying machine, shows a low reflectance over the entire wavelength range of the visible region, and becomes a black color as a whole. .

Due to such characteristics, 500 nm to 600 n
purple system, sepia system with low reflectance in the wavelength range of m
When the indigo system is copied with a copying machine,
Even if the reflectivity is high at 0 nm or more, the copy machine has low sensitivity in this area, and the copied matter does not properly respond to the reflectivity 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 darkened as a whole, and the difference in density from the copied image information is reduced.
Furthermore, the spot pattern such as the tint block is darkened, overlaps with the image information, and is camouflaged.

On the other hand, in the present invention, the tint or the group of lines serving as the background is set to a density close to the resolution of a digital copier, and the angle at which moire (interference fringes) is generated by copying with a digital copier. Printed at an angle.

That is, the digital copier has a characteristic that, when tilted with respect to the reading reference direction, moire occurs on the copy paper side depending on the tilt direction.
For this reason, even if it is printed at an appropriate darkness so that the image information printed in the non-copyable area is easily visible, when copied with a digital copying machine, the occurrence of moire causes the image information to be concealed, Combined with the effect of the mottled pattern, it becomes unreadable.

[0019]

BRIEF DESCRIPTION OF THE DRAWINGS FIG.

FIGS. 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 of the non-copyable form 1.

The non-copyable area 2 has a size of 500 nm to 60 nm.
A spot pattern 3 such as a tint block or the like formed by randomly overlapping numbers and the like as shown in an enlarged view in FIG. Are shaded. This is 50 ~
80% of dots or lines are printed as the background 4
Further, the same color is formed by solid printing the copy-forgery-inhibited pattern.

In the non-copyable area 2, the reflectance increases in the purple system at 500 nm or less and 600 nm or more. In the sepia system, the reflectance increases at 600 nm or more. Further, in the indigo system, the reflectance increases below 500 nm. Therefore, as shown in FIG.
In the range of 00 to 500 nm and 600 to 700 nm, the sensitivity of the photosensitive drum of the copying machine is poor, and the color reflected in the wavelength regions at both ends has little effect on the sensitivity of the copying machine. As a result, the reflectance becomes low and the color becomes black.

For this reason, when printing is performed on the non-copyable area 2 by a printer, black printed characters and characters can be distinguished from the non-copyable area 2 by the difference in color tone due to each color. Has occurred.

On the other hand, when the image printed on the non-copyable area 2 is copied by a copier, the portion of the non-copyable area 2 becomes blackish as a whole, and The pattern is overlapped with the image information and camouflage is applied.

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

FIG. 6 shows this relationship. Assuming that each dot is o, the dots o are equally spaced at an interval n and inclined 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 tint point of the background portion 4 and
The relationship with the occurrence of moiré will be described.

As shown in FIG. 7, the digital copier 10
Represents the reflected light illuminated on the non-copyable form 1 serving as the original G
It is introduced into an image pickup device 10a such as a CD, performs photoelectric conversion, performs a binarization process based on an analog signal corresponding to the density of image information, and copies image information based on the image signal. is there.

Although the resolution of such a digital copier is dramatically improved as compared with the conventional analog copier, the read pixels 20 in the CCD image pickup device 10a are not required.
It is known that interference occurs depending on how the dot G overlaps the halftone dot of the document G, and moire occurs as shown in FIG.

Table 1 shows the results of a test conducted by the present applicant for the occurrence of moiré using a Canon color copier "Pixel Dio (CLC-500)".

[Table 1]

As is clear from this table, for example, 85
In the case of a line, a dot having a line density of 30%, the inclination angle is 30.
In the case of °, moire does not occur on the copy paper when copying.
However, at the inclination angles of 15 °, 20 ° and 75 °, it is understood that moire is clearly generated.

For this reason, when printing is performed on the non-copyable area 2 by a printer, the character can be distinguished from the non-copyable area 2 by the difference in the color tone due to the black print character and the color tone due to each color. , The required reflectance is secured, and the printed characters can be easily read.

In the above-described configuration, the background portion 4 is formed by tints. However, the background portion 4 may be formed by a group of lines. In this case, too, an angle at which moire is generated by copying with a digital copying machine. , With respect to the reading reference direction.

As described above, the non-copyable area 2 is
Since the background portion 4 is made of a color such as a purple type having a low reflectance in a wavelength range of m to 600 nm and a halftone dot or a line group of 50 to 80%, as described above, due to the sensitivity of the copying machine, As a whole, it becomes dark, and furthermore, due to the mottle pattern 3 and the black mottle pattern being overlapped with the character, the moire occurs on the copy paper, making the character indecipherable. Become. Since the moiré causes a concealing effect in a superimposed manner, the image information of the copy cannot be read even if the uncopyable area 2 is not so darkened. Therefore, a document with good visibility can be formed.

[0034]

According to the present invention, as described above, 500 nm
Digitally copy tints or lines that are made of colors such as purple, sepia, and indigo that have low reflectance in the wavelength range of -600 nm, have spots such as tint block, and become the background portion 4. A non-copyable area 2 is formed by printing at a density close to the resolution of the copying machine and at an angle that causes moiré by copying with a digital copier and tilting it with respect to a reading reference direction to form a non-copyable area 2. Information is printed. Therefore, in a copied state, the non-copyable area 2 is darkened and the spots 3
Overlaps with the image information to give camouflage, and the occurrence of moire makes it impossible to read the image information, thereby achieving sufficient confidentiality. Further, since the moiré causes a concealing effect in a superimposed manner, even if the non-copyable area 2 is not so darkened, the copy cannot read the image information and a document with good visibility can be created. And other excellent effects.

[Brief description of the drawings]

FIG. 1 is a plan view of a form 1 that cannot be copied 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 a non-copyable area 2;

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

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 tilt angle θ of a dot.

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

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

[Explanation of symbols]

 1 Non-copyable form 2 Non-copyable area 3 Spots 4 Background

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int. Cl. ⁶ , DB name) B41M 3/14 B42D 15/10 H04N 1/00-1/207 G03G 21/00 560-562 G03G 21/04

Claims (1)

(57) [Claims] 1. A color having a low reflectance in a wavelength range of 500 nm to 600 nm, such as a purple system, a sepia system, or an indigo system, and 50 to 80% of dots or lines are printed as a background portion. In the case where a copy-forgery-inhibited area formed by solid printing of a copy-forgery-inhibited pattern is provided, the dot or line group serving as a background portion has a density close to the resolution of a digital copier and is copied by a digital copier A non-copyable form, wherein the form is printed at an angle at which moiré is generated at an angle with respect to a reading reference direction.