JPH01121885A - Method for preventing reproduction of printed matter - Google Patents

Abstract

PURPOSE:To prevent reproduction of printed matter by forming the printed matter in such a manner that the characters, etc., thereof are easily legible and discriminatable but that the copied characters, etc., thereof are hardly legible and discriminatable. CONSTITUTION:Base paper having a high reflectivity of light of 480-580nm wavelengths is printed by printing ink of the color having sensitivity with a photoconductive material to be used for an electrophotographic sensitive body of a copying machine. Combination of the colors which do not give an uncomfortable feel to the eyes are selectable and the printed matter having high practicability is provided but once this printed matter is copied, only the copy which is uncomfortable to the eyes or is illegible is obtainable; therefore, one can discriminate at a glance that the printed matter is copied. In addition, the copied matter is hardly visible and is far from being practicably used. The duplication of the printed matter is thereby effectively prevented.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a method for preventing copying of printed matter. Specifically, printed matter is easy to read and distinguish, but when it is copied, it is difficult to read and distinguish the characters, etc. This invention relates to a method for preventing reproduction of printed matter by making it difficult to distinguish.

[Background of the Invention] In recent years, printing technology and copying technology have progressed, and the quality of printing on printed matter such as academic books on science, engineering, medicine, etc. or securities has improved significantly, and even when looking at copies of such printed matter, it is difficult to identify which one is the original. The quality has improved to such an extent that it is no longer possible to tell.

However, copying academic books causes the problem of copyright infringement, and copying securities, etc. causes the crime of counterfeiting securities.

These problems can be overcome if the person doing the copying is careful, but the reality is that printed matter is frequently copied, causing problems such as copyright infringement.

Incidentally, the technology for anti-counterfeiting printed matter described in Japanese Patent Application Laid-open No. 58-40581 is known, but this technology does not provide a fundamental solution as it is possible to see that it has been copied but it is also decipherable. Not yet.

[Object of the Invention] Therefore, the object of the present invention is to reproduce a printed matter in which, even if the characters etc. appearing on the printed matter are clearly legible, the characters etc. on the copy are difficult or illegible when the copy is copied. The purpose is to provide a method of prevention.

[Means for Solving the Problems] The present inventor has made extensive studies to achieve the above object, and as a result, has arrived at the present invention.

That is, the method for preventing copying of printed matter according to the present invention is 480++
■On base paper with a color that has a high reflectance of light with a wavelength of ~580 nm,
It is characterized by printing with printing ink of a color that is sensitive to the photoconductive material used in the electrophotographic photoreceptor of a copying machine.

[Structure of the invention] The present invention will be explained in detail below.

Generally, electrophotographic copying machines use selenium,
Inorganic substances such as zinc oxide and cadmium sulfide, as well as a wide variety of organic substances are used. These photoreceptors are used in the near ultraviolet region (approximately 4
00nm or less) or near-infrared (approximately 700n or more)
Many of the recently developed organic photoreceptors are sensitive to near-infrared light. Therefore, when characters or the like on a printed matter absorb light of these wavelengths, a latent image is formed on the electrophotographic photoreceptor and is copied.

In the present invention, "the photoconductive material used in the electrophotographic photoreceptor is sensitive" means that it is sensitive to the above-mentioned near ultraviolet or near infrared light.

A color with a high reflectance for light having a wavelength of 48 On+s to 581) nm is green, which has a low absorbance in this range.

That is, when a green base paper with a high reflectance for wavelengths in this range is used and a copying machine is used to copy, the color tones with a higher reflectance will be copied black. The characters printed on this base paper in blue, red, black, etc. can be distinguished, but if you copy this printed matter, the entire copy will be black, and the characters will be difficult to distinguish or you will only get copies that are extremely difficult to see. .

The same can be said for the base paper using a red-based color of Boons to 840 nm, which is orange or higher. However, in order to draw characters on base paper of this color, it is necessary to use dark red or black ink, resulting in prints that are extremely difficult to read.

In the present invention, the printed matter is easy to see in practical use, but when it is copied, only a copy that is difficult to see is obtained, making it difficult to put it to practical use.

Therefore, in the present invention, it is possible to combine ink of an easily visible color corresponding to the color of the base paper whose absorbance pattern shown in FIG. 1 shifts toward the short wavelength side or the long wavelength side. .

[Example] Base paper No. 1-No. has the absorbance shown in FIG.

I prepared 3.

A pattern was printed on this using stencil ink (manufactured by Riso Kagakusha) to obtain a printed matter.

Table 1 shows the results of visual inspection of the "legibility" of the printed matter.

Table 1 Notes 0: Easy to see, Δ: Hard to see, ×: Not visible (hereinafter,
The same shall apply. ) Next, υ-Big 4500 (manufactured by Konishiroku Photo Industry Co., Ltd.)
Copying was performed using the following to obtain a copy.

Table 2 shows the results of visual inspection of the "legibility" of the copies.

Table 2 [Effects of the Invention] According to the present invention, a pattern is printed in a color that is easy to distinguish on a base paper with a high reflectance in the wavelength range of 480 nm to 580 nm, and does not cause discomfort to the eyes. It is possible to select a combination of colors that are not used, and it is possible to provide printed matter that is highly practical. Also, if you copy this printout.

It is uncomfortable for the eyes or only hard-to-read copies are obtained, so it is easy to tell at a glance that they are copies, and the copies are difficult to see and cannot be used for practical purposes. Can be effectively prevented.

Therefore, the present invention can prevent copying of academic books on science, engineering, medicine, etc., securities, etc., thereby contributing to copyright protection, counterfeiting, and the like.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a graph showing the relationship between absorbance and wavelength of the base paper used in the present invention. Patent applicant Nobuaki Sakaguchi, agent of Konica Co., Ltd., patent attorney

Claims (1)

[Claims] It is characterized by printing on base paper of a color that has a high reflectance of light with a wavelength of 480 nm to 580 nm, using printing ink of a color that is sensitive to the photoconductive substance used in the electrophotographic photoreceptor of a copying machine. Act on Prevention of Copying of Printed Materials.