JPS6087380A - Camouflaging method of latent image for copy prevention on printed matter - Google Patents

Abstract

PURPOSE:To make it evident that a sheet of paper is a copy by using an overprinting plate having a pattern which interferes with ground tint (line-like) of a latent image plate to form moire fringes, and overprinting hypochromic data which is not reproduced by a copying machine on a form surface. CONSTITUTION:The latent plate 2 which has a latent image 3 displaying COPY consisting of 150-line and 10% dots and a background 4 consisting of about 50- 60-line and 10% ground tint (line-like) on the white ground at the circumference of the latent image is used for hyperchromic printing on the surface of a form 1. Then, the overprinting plate 5 having the waveform pattern 6 consisting of parallel lines which form moire fringes when interfering with the ground tint (line-like) of the background 4 is used to perform hypochromic overprinting which is not reproduced by the copying machine on the form surface, camouflaging the latent image. Consequently, the moire fringes which are glaring to the naked eye are formed on the surface of the printed matter, so the presence of the latent image 3 becomes hard to discriminate and only the background 4 is reproduced on a copying machine without the latent image 3 nor pattern 6, distinguishing between the latent image 3 and background 4.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for camouflaging a latent image provided on a printed matter to prevent copying.

In order to prevent important documents such as securities from being forged using a copying machine, a latent image such as rVOIDJ is printed on the surface of the paper, and when the paper is run through a copying machine, the latent image can be visually distinguished from the background. There are six known cases of this. However, in this case, there is a difference in size between the halftone dots that make up the latent image and the background, and one halftone dot cannot be reproduced by a copying machine, but the other halftone dot is of a size that can be reproduced by a copying machine, and The existence of the latent image is confirmed by the difference in brightness between the two images. In order to prevent the latent image from being recognized by the naked eye before copying, there is a method of providing a camouflage (above and in front of both the latent image and the background) as a prior art, but since both the latent image and the background are a combination of points of the same shape, If the dot size difference is not extreme, the latent image will not appear clearly after copying, but if the dot size difference is made too extreme, the latent image will be visible to the naked eye even if a camouflage is installed, making it visible to the naked eye. Also, there were limitations in the placement and color tone of the upper section Shikam 7 Large, making it difficult to obtain good-looking printed matter.

In the present invention, the latent image is dotted, the background is made up of lines, and a pattern that interferes with the lines and forms a moiré pattern is overprinted from the top surface of these lines, so that the latent image is sufficiently covered. This method provides a camouflage method in which the latent image clearly appears after copying, making it obvious at a glance that it is a copy.Next, to explain based on the drawing, 150 lines, 1σ halftone dots, etc. A latent image plate 2 is provided with a latent image 3 labeled rcOPYJ, and a background 4 with 50 to 60 lines of about 10 cm on a white background around the latent image is used to print a dark color on the surface of the paper 10. Print. Next, using an overprint plate 5 having a waveform pattern 6 made of parallel lines that forms a moiré pattern 7 when it interferes with the background 400,000 lines, a light-colored overprint that cannot be reproduced by a copying machine is applied to the surface of the paper. latent image 3
camouflage.

The surface of the printed matter thus obtained has a moire pattern 7 that confuses the naked eye, making it difficult to identify the latent image 3, but when it is put into a copying machine, the latent image 3 and the pattern 6 are Result latent image 3 that is not reproduced and only background 4 is reproduced
In other words, when the waveform pattern 6 is overprinted on the surface of the paper 1, it interferes with the lines of the background 4, which is underprinted, and a moiré pattern 7 is formed. It appears that only the moiré pattern of the doves is printed, and neither the latent image nor the background is visible, and the existence of the latent image is not known. However, when applied to a copying machine, the latent image 3 consisting of 150 lines and 10% halftone dots is not reproduced and appears whitish, whereas the background 4, which is 50 to 60 lines and 10 lines, is reproduced and becomes a dark color. Moreover, since the overprinted waveform pattern 6 is not reproduced in a light color, only the difference in density between halftone dots and parallel lines becomes noticeable, resulting in latent image 3.
It is clearly identified and it is obvious at a glance that it is a copy1.

As described above, the present invention is characterized in that the pattern 6 overprinted on the upper surface of the latent image 3 does not itself have a moire pattern, but rather interferes with the parallel lines of the background 4 to form a moire pattern. There is. The line that interfered with pattern 6 has lost its unique shape, so the border with the halftone dot is unclear. 3 is a dimension that is buried in the moire pattern 7 and is no longer visible.

However, in the present invention, a method is used in which underprinting is performed using the latent image plate 2 and then overprinting is performed using the printing plate 5. Therefore, the obtained printed matter is printed on the paper 1 as shown in the fourth figure. The ink layer B has a structure in which a latent image is formed on the upper surface and an ink layer B (on the upper surface of the background ink layer) is polymerized. Therefore, the color tone of the ink layer B can be selected from a variety of colors, so that the color pattern can be adjusted according to the purpose and appearance of the printed material. In addition, by changing the shape and angle of the pattern 6, it is possible to form a moiré pattern with a wide variety of variations, which is useful for creating any decorative effect on printed matter, and camouflaging the latent image for preventing copying on printed matter. The present invention is extremely advantageous as a method for doing so.

[Brief explanation of the drawing]

FIG. 1 is a plan view of a latent image plate used for carrying out the present invention, FIG. 2 is a plan view of an overprint plate, FIG. 3 is a plan view of a printed matter obtained by the method of the present invention, and FIG. 3 is a partially enlarged sectional view of FIG. 3, and FIG. 5 is a plan view of a copy of the printed matter. 1 is paper, 2 is latent image plate, 3 is latent image, 4 is background 5 is overprint plate, 6 is no (turn), 7 is moiré pattern. Patent applicant: Hosokawa Letterpress Co., Ltd. Representative, patent attorney: Yuki Kaneko Hiko

Claims (1)

[Claims] Printing is performed on the paper surface using a latent image plate that has a latent image like halftone dots that cannot be reproduced by a copying machine and a background like lines that can be reproduced by a copying machine. A method for camouflaging a latent image for preventing copying in printed matter by using an overprint plate having a pattern that interferes to form a moiré pattern and applying light-colored overprint marks on the paper surface that cannot be reproduced by a copying machine.