JPS6261943B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a method for producing a film original plate for producing printed matter suitable for preventing misuse such as forgery and alteration due to copying.

<Prior Art> With the development and widespread use of improved copying machine technology, various documents are being copied in a manner that is confusingly similar to the real thing, leading to unauthorized use of altered and forged documents.

Therefore, a latent image that is difficult to discern with the naked eye is printed on the surface of the paper, indicating "invalid", "copy", etc.
Recently, printed matter has been developed in which a latent image appears when it is copied so that it is obvious that it is a copy. The techniques disclosed in Japanese Patent Publication No. 55-45400 and Japanese Patent Publication No. 58-47708 are good examples. What these two have in common is that the latent image and the surrounding background are composed of halftone dots of different sizes, and when the latent image and the background are made up of small halftone dots, they are reproduced when the copy machine is used. First, the background or latent image made up of large halftone dots is reproduced, and the unreproduced areas appear white and the reproduced areas appear dark, and the difference between them reveals the presence of the latent image. It is characterized by being visible.

In contrast, the printed matter shown in Japanese Patent Publication No. 55-45400 consists of only large and small halftone dots printed on the surface of the paper, whereas the printed matter shown in Special Publication No. 58-47708 consists of halftone dots and cams. Since it has a structure incorporating a flage pattern, the latter is more suitable than the former for masking the presence of a latent image since the paper surface before copying dazzles the naked eye.

<Problem to be solved by the invention> However, even if a camouflage pattern is incorporated, the latent image and the background are composed of halftone dots of the same shape, so if the size of the halftone dots is made extreme, the paper surface will look unnatural. There are disadvantages that can be seen with the naked eye, and as a result, certain limitations must be placed on the ratio of the size of the latent image to the halftone dots, and as a result, large halftone dots will not necessarily be reproduced clearly when put on a copying machine. Of course, there is the disadvantage that a clear copy image cannot be obtained because the halftone dots are divided by the camouflage pattern. It goes without saying that these problems with printed matter are caused by the plate structure before manufacture.

<Means for Solving the Problems> The present invention provides a method for obtaining a film original plate for producing printed matter, which eliminates the above-mentioned disadvantages, namely, polymerizing a parallel line negative film on the upper surface of an unexposed film, and A first latent image film is superposed on the upper surface of the parallel line negative film, and a camouflage negative film is further superposed on the upper surface of the first latent image film to form a four-layer structure film group, and the film group is attached from above to the film group. A method for producing a film original plate, in which a line negative film is replaced with a halftone negative film after a first exposure is given, and a first latent image film is replaced with a second latent image film, and then a second exposure is given. be.

<Example> In Fig. 1, 1 is unexposed film, 2 is 60
A line negative film with 90% of the lines is superimposed on the top surface of the unexposed film 1, and a latent image positive film as the first latent image film on which the word "copy" is formed is superimposed on the top surface of the line negative film 2. 4 is a negative film for camouflage on which a ripple-like complex camouflage pattern 5 is formed, which is superimposed on the upper surface of the latent image positive film 3. The light source 6 provided above the four-layered film group first illuminates the first
Give second exposure. As a result of this first exposure, the word "copy" is not exposed on the bottom unexposed film 1, but 60 lines and 10% of the lines are exposed as a camouflaged pattern. Then, as shown in the second figure, the 150-line, 90% halftone dot negative film 7 is replaced with the straight-line negative film 2, and the latent image negative film 8, which is the second latent image film on which the word "copy" is formed, is inserted into the latent image. After replacing the image positive film 3, a second exposure is applied using the light source 6. Then, the replaced halftone negative film 7 is 15
As a result of being exposed to the unexposed film 1 within the range of the word "copy" on the latent negative film 8 as a 0 line 10% halftone dot, the word "copy" and its surroundings are formed by camouflaged halftone dots. A film master plate with a camouflaged line pattern is obtained.

When printing is performed on paper using the film original plate thus manufactured, a latent image 10 labeled "copy" consisting of 150 lines and 10% halftone dots incorporating a camouflage pattern (not shown) is formed. A printed matter A is obtained having a background 11 consisting of 60 lines and 10% parallel lines incorporating a camouflage pattern (not shown) around the latent image (FIG. 8).

Then, when this printed matter is run through a normal copying machine,
The latent image of the "copy" made up of halftone dots is not reproduced and appears as a white outline, whereas the background 11 made up of lines is reproduced and appears in a dark color, and the difference in brightness between the two becomes noticeable. The word "copy" is visible (Fig. 9).

Contrary to the above embodiment, the latent image positive film 3 during the first exposure is used as the latent image negative film 8, and the latent image negative film 8 during the second exposure is used as the latent image positive film 3.
In this way, a film original plate is created in which the word "copy" is made up of parallel lines and the rest of the background is made up of halftone dots, and the prints obtained from this original plate are then sent to a copying machine. When this is done, the latent image made up of parallel lines is reproduced in a dark color, but the background made up of halftone dots is not reproduced and becomes a white outline, so the difference in brightness between the two becomes noticeable and the word "copy" is visible.

Note that when the exposure direction of the copying machine is in the direction of arrow 12 as shown in Figure 10, when the lines of the set printed material match the exposure direction, the exposure effect works and the lines are reproduced in a particularly dark color. .

<Effects of the Invention> Since the present invention uses a line negative film and a halftone dot negative film in the original plate manufacturing process, the latent image and background of the obtained original plate are composed of halftone dots on one side and lines on the other. The printed matter made from this original plate also has square lines and halftone dots, and when it is run through a copying machine, the lines are in a continuous pattern, so they reproduce better than halftone dots, and therefore the latent image and background after copying. There is a clear difference in brightness and darkness. Even if the surface of the printed matter dazzles the naked eye because the camouflage pattern 5 interferes with the latent image 10 and the background 11 and makes the boundary between the two unclear, the camouflage pattern 5 interferes with the latent image 10 and the background 11. Of course, the camouflage pattern is not a problem.

[Brief explanation of the drawing]

The figures show an example, and FIG. 1 is a side view at the time of first exposure showing the state in which a film master is prepared;
Fig. 2 is a side view during the second exposure, Fig. 3 is a plan view of the parallel line negative film, Fig. 4 is a plan view of the latent image positive film, Fig. 5 is a plan view of the negative film for camouflage, and Fig. 6 is a plan view of the negative film for camouflage. 7 is a plan view of a latent image negative film, FIG. 8 is a plan view of a printed matter obtained by the film original plate with the camouflage pattern omitted, and FIG. 9 is a plan view of a halftone negative film. The figure is number 8
FIG. 10 is a plan view showing a state in which printed matter is copied. FIG. 10 is a plan view showing a state in which printed matter to be copied is set. 1... Unexposed film, 2... Straight line negative film, 3... Latent image positive film, 4... Negative film for camouflage, 7... Halftone negative film, 8
...Latent image negative film.

Claims (1)

[Scope of Claims] 1. A line negative film is superposed on the upper surface of the unexposed film, a first latent image film is superposed on the upper surface of the line negative film, and a camouflage negative film is further superposed on the upper surface of the first latent image film. The films are polymerized to form a film group with a four-layer structure, and after a first exposure is applied to the film group from above, the line negative film is replaced with a halftone negative film, and the first latent image film is replaced with a second latent film. A method for producing a film original plate for producing an abuse-proof printed matter by copying, which is replaced with an image film and then subjected to a second exposure. 2. The manufacturing method according to claim 1, wherein the first latent image film is a latent image positive film and the second latent image film is a latent image negative film. 3. The manufacturing method according to claim 1, wherein the first latent image film is a latent image negative film and the second latent image film is a latent image positive film.