JPH0414220Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to printed matter that is difficult to reproduce with a color copying machine.

[Conventional technology]

As electrophotographic advances have brought sophisticated color copying machines into practical use, inconvenient reproductions of multicolored printed matter are often attempted.
Efforts are constantly being made to prevent the forgery and alteration of various documents, particularly securities.

Traditionally, important securities have been printed using techniques such as engraving intaglio printing, rainbow printing, or orflo printing, which can be used as a countermeasure against duplication by color copiers, but in addition to high printing costs, they also Since the printing method is limited, it cannot be said to be common.

[The problem that the idea aims to solve]

The purpose of this invention is to deal with such problems, and to take advantage of the differences in the copying ability of color copiers and printing technology, to divide the printed image into constituent parts with different printing conditions, and to distinguish between parts that are different from each other when visually inspecting the original. The object of the present invention is to provide a printed matter in which the difference is virtually invisible, but a difference appears in a copy obtained by using a color copying machine, and the fact that the copy has been made can be recognized.

[Means to solve the problem]

Printed matter that is difficult to reproduce with the copier of this invention is
At least a part of the printed image is printed using solid printing with an ink density that does not reach the lowest density that can be reproduced with a color copying machine, and the other part is printed with an ink density that does not reach the lowest density that can be reproduced with a color copying machine. Printing is done using ink that has reached a certain density, and the size of the dot is larger than the minimum dot size that can be copied with a color copying machine, and although the differences between each part are virtually invisible to the naked eye, it is possible to copy with a color copying machine. When this happens, the former part will be highlighted.

In the following description with reference to the drawings, a typical aspect is as shown in FIG.
(The letter "A" part in the figure) is printed solidly with thin ink, and the other part 7 (the part other than the letter "A" in the figure)
This is printed matter 1 printed with large halftone dots using dark ink of the same color. The density of the ink in the portion 5 is a density that does not reach the copying capacity of the copying machine, and the density of the ink in the other part 7 is a density that reaches the copying capacity of the copying machine. The size of the halftone dot is larger than the minimum size that can be copied.

[Effect]

When this printed matter is run on a color copying machine, differences that were not noticed visually become apparent in the copy 2 as shown in FIG. Solid printing part 5
This is because the image is not copied by the color copying machine and instead becomes a blank area 9.

The density of ink for solid printing, the size (number of lines), and area ratio of halftone dots for halftone dot printing are determined as necessary depending on the resolution and color restoration capabilities of the color copying machine likely to be used for duplication. You just need to do some experimentation and make your choice. To give an example of halftone dots, the number of lines is 133.
/ inch - halftone dots with an area ratio of 20% or 10% cannot be resolved by color copying machines currently in use,
Since it becomes a blank space, it is necessary to make halftone dots larger than this limit.

[Effect of idea]

The printed matter of the present invention is immediately recognizable as a copy because the copy obtained by a color copying machine has a different pattern from the original, and as a result, it is extremely difficult to reproduce.

The printed matter of the present invention can be produced by relatively simple printing means such as offset printing and letterpress printing, and the type of printing material is not particularly limited.

[Brief explanation of the drawing]

The drawings are for explaining the principle behind the difficulty in copying the printed matter of the present invention; Figure 1 shows the configuration of a typical printed matter, and Figure 2 shows the configuration of its copy. . 1... Printed matter, 2... Copy, 5... Part of the pattern (solid printing), 7... Other part of the pattern (large halftone dot printing), 9... Blank area.

Claims (1)

[Scope of utility model registration request] At least a part of the printed image is printed using solid printing with an ink density that does not reach the lowest density that can be reproduced with a color copying machine, and the other part is printed with an ink density that does not reach the lowest density that can be reproduced with a color copying machine. Printing is done using ink that has reached a certain density, and the size of the dot is larger than the minimum dot size that can be copied with a color copying machine, and although the differences between each part are virtually invisible to the naked eye, it is possible to copy with a color copying machine. Printed matter that is difficult to reproduce with a copying machine, with the former part being white when printed.