KR20230075104A - method of security printing and prints made by the same - Google Patents

Abstract

Disclosed are a secure printing method and a printout by the method, capable of displaying an image with more than one print status grade when copying, wherein the secure printing method may comprise: when viewing points or lines that appear on a printed printout with a naked eye, defining the minimum diameter or width of a point or line that is copied as 100% where the point or line copied looks exactly the same as the point or line to the naked eye and defining the maximum diameter or width of a point or line that cannot be copied at all as 0%; and setting the diameter or width of a point or line to have one or more steps, wherein the diameter or width of the point or line ranges from 100% to 0%, thereby enabling printing that has all of: a diameter or width less than or equal to the diameter or width of the point or line at 0%; a diameter or width greater than or equal to the diameter or width of the point or line at 100%; and a diameter or width of a point or line corresponding to more than one step in between.

Description

Method of security printing and prints made by the same}

The present invention relates to a printed matter and a printing method, and more particularly, to a printed matter for security that can be used in the field of document security and the like, and can implement a copy protection mark during copying, and a printing method thereof.

It is considered very important to keep and protect the confidentiality of important matters related to competition between companies and security between countries. There is a high risk of leakage of such confidential information in the form of photos, documents, or electronic files in recent years, so countermeasures are required.

Traditionally, documents that can convey a lot of information about confidential matters are classified into confidentiality levels and not marked. In many cases, it is treated with a sensitive material, and leakage to the outside is prevented by installing a detector capable of detecting such a material at the entrance and exit of a certain area where it is stored.

However, recently, taking a picture using a personal information device such as a smart phone and leaking it, or leaking it in the form of a copy rather than the original using a photocopier or scanner is a problem because it can be avoided. In the following, the problematic behavior will be expressed in a broad sense by simplifying and expressing the act of copying, the result being a copy, and the used device being commonly referred to as a copier.

In order to solve this problem, it is invisible to the naked eye, but when copying using a copier or scanner, the secret document is displayed on the copy so that it can be easily checked through search when it is taken out, or it is difficult to distribute such a document. Or, there was a case where the contents did not appear on the copy at all, so that the copy itself was not made.

This case is usually possible because the object is recognized differently by the naked eye and the electronic and optical visual data detection and processing means used in cameras, copiers, and scanners can recognize the object differently.

That is, by using dots or lines smaller than the minimum size that can be distinguished and recognized by a machine in copying or scanning by a scanner, it is possible to create a shape that is visible to the naked eye and invisible to copying through the halftone dot configuration. In addition, if the original document is made of copy protection or copy indication paper using this principle, the copy can be marked for copy on the document.

In order for this means, such as copy marking, to be possible, once a printed matter is made through printing, through a specific printing method, as mentioned above, it is invisible to the naked eye, but when copying, it is necessary to make the copy appear confidential, or the copy contains the original content. It is necessary to prevent it from appearing.

Republic of Korea Patent Application No. 10-2020-0014169 discloses a print or printing structure composed of a background portion and a text portion to prevent forgery. Here, when viewed with the naked eye, it is recognized without distinction between the background part and the text part, and when recognized by scanning means including copying and shooting, the text part is recognized brighter than the background part to prevent forgery. to perform the function.

Korean Patent Registration No. 10-1391756 Korean Registered Patent No. 10-1348599 Korean Patent Application No. 10-2020-0014169

However, according to these existing copy protection techniques, in many cases, the mark revealed by copying is simply displayed as 'COPY' by simply distinguishing the character part and the background part, and even if it is expressed with other symbols or characters, it is simply Whether it is a copy or not is limited to the case of making it simple to determine.

However, as there are levels or types of non-marking, it may be necessary to express the markings that appear on copies to prevent copying in various ways as needed, and respond appropriately accordingly. For these various expressions, it would be desirable if there was a technology that enables more diverse expressions because there is a limit to the expression simply divided into a character part and a background part as in the prior art in the copy appearing after copying.

Therefore, the present invention uses the basic principle of the radiation-jamming technique to realize contrast that is not implemented in the existing radiation-jamming technique, but shows the contrast grade through the difference in the degree of reading by the copier when copying. An object of the present invention is to provide a method for expressing characters, figures, symbols, or other specific shapes that were not visible before copying through the contrast grade as a picture or shape with a difference in contrast, and a printed product made by such a method.

The security printing method of the present invention for achieving the above object is,

When copying in the middle of a point or line that appears on a printout when viewed with the naked eye, the minimum diameter or width (line width) of a point or line that is copied so that it looks exactly the same as when seen with the naked eye is 100%, and the copying is not possible at all. Assuming that the maximum diameter or width of a point or line is 0%, the diameter or width of the point or line is determined in one or more steps between 100% and 0%, and the diameter or width less than the diameter or width of the point or line at 0% Existing printing conditions at the time of copying by printing to have both a diameter or width greater than the diameter or width of a point or line at 100% and a diameter or width of a point or line corresponding to one or more steps in the middle , For example, to have one or more printing status grades, such as a contrast grade, in addition to the background and text expressed in black and non-printing conditions, such as white (more specifically, a gray grade area having one or more brightness grades) It is characterized by having more.

Expressed in more detail, the security printing method of the present invention

When copying in the middle of a point or line that appears on a printout when viewed with the naked eye, the minimum diameter or width of a point or line that is copied so that it looks exactly the same as when seen with the naked eye is 100%, and the point or line that cannot be copied at all is called 100%. If the maximum diameter or width is 0%, checking and determining the size or line width of the dots corresponding to 100% and 0%, respectively;

Determining the dot size or line width between 100% and 0% in one or more steps;

Determining which position or area of the print target is to have which printing state level or grade;

According to the determined step, printing may be performed with dots or lines having a corresponding dot size or a corresponding line width for each location or region of the printing target to produce a printed product.

The security print of the present invention for achieving the above object,

In the middle of the dots or lines that appear on the printout when viewed with the naked eye, after copying, the minimum diameter or width of the dot or line is 100%. , and the maximum diameter or width of a point or line is 0% for a thing that cannot be copied at all (the part that is displayed in white during copying), and the diameter or width between 100% and 0% is set to have one or more steps , points or lines less than or equal to 0% diameter or width, points or lines greater than or equal to 100% diameter or width, points or lines less than or equal to diameter or width corresponding to at least one of the above steps between 0% and 100% With all the lines, in addition to the part expressed in the printed state at the time of copying and the part expressed in the completely non-printed state, with a printing state grade between these two states, for example, to have one or more parts expressed in gray with a contrast grade characterized by being made.

In another aspect, the security printed matter of the present invention prints 100% of the minimum diameter or width of the point or line to be copied so that it looks exactly the same as when viewed with the naked eye when copied in the middle of the point or line appearing on the printout by printing when viewed with the naked eye. The maximum diameter or width of a point or line that cannot be copied at all is called the 0% printing state, and the size that can achieve one or more stages of the printing state corresponding to the printing state between the 100% printing state and the 0% printing state It is characterized in that at least three different printing states or steps of 100% or less and 0% or more are included in the printed matter when determining the dot or line width of the line.

That is, the printed matter of the present invention is made to include three or more different printing conditions that make it look different when copying. Prints having three or more different types of dot sizes greater than or equal to the corresponding dot size may be mentioned.

In the present invention, a point actually has an area and may be formed in various shapes such as a circle, a polygon, a star shape, and the like. That is, the point of the present invention may be formed of one or a combination of closed curve two-dimensional figures including circles, polygons, and star shapes that can measure areas. Here, the diameter or width means an arbitrary length that can characterize the size of the dot, and it is also possible to set different rules for measuring the length according to the shape of the actual dot. For example, in the case of a circle, it can be determined by the diameter or radius, by the length of a side or diagonal of a square, and by the distance between an angle and the midpoint of the corresponding side in the case of a pentagon.

In the present invention, it is preferable that the lines have a certain width, that not only straight lines but also curved lines are possible, and that the distance between the lines is also constant so that the two lines run in parallel.

According to the present invention, the basic principle of the existing copy-jamming technique is used, but the contrast grade is expressed through the difference in the degree of reading by the copier during copying, and through the contrast grade, characters, figures, symbols or other specific characters that were not visible before copying are used. The shape can be expressed as a picture or shape with contrast.

Therefore, by implementing the copy protection mark in various forms, it can be used for classifying copy-protected objects, such as indicating the copy-protection level of the object, and can be dealt with appropriately for the classification.

On the other hand, if conversely, the anti-copying pattern can be a criterion or basis for determining whether an original document is authentic. In this case, for example, if the copy prevention pattern or shape of the original document is simple, it is possible to easily create such paper and a document using such paper and use it to leak the original document, and copying or scanning visible through copying or scanning like the present invention If the prevention pattern is made in a complex form using the brightness grade, it will be possible to use it to determine the authenticity of the original.

1 is an enlarged view showing subdivided circular halftone dot configurations in a copy object subdivided into six according to circular halftone dot configurations compared with each other;
Figure 2 is a comparison diagram showing the brightness of objects divided into 6 pieces having the same halftone dots as the enlarged view of Figure 1 with the naked eye;
Figure 3 is a comparison diagram showing the brightness of the copy after copying the object subdivided into six pieces having the same halftone dots as the enlarged view of Figure 1, compared with the naked eye;
4 is an enlarged view showing subdivided square dot configurations in a copy object subdivided into six according to the square dot configuration by comparison with each other;
Figure 5 is a comparison diagram showing the brightness of objects divided into 6 pieces having the same halftone dots as the enlarged view of Figure 4 with the naked eye;
Figure 6 is a comparison diagram showing the brightness of the copy after copying the object subdivided into six pieces having the same halftone dots as the enlarged view of Figure 4, compared with the naked eye;
7 is an enlarged view showing the configuration of linear dots in five types of copy objects having the same ratio of printing area per unit area but different convergence degrees, compared with each other;
8 is a reference diagram showing that a copy of an object using the present invention can express various expressions with three or more areas having different brightness.

Hereinafter, the present invention will be described in more detail through examples with reference to the drawings.

First, as a premise for ease of explanation, at least one step is desired between the size corresponding to 0%, which is not copied at all by the radiation interference technique, and the size corresponding to 100%, which is completely copied without any difference from the line width and the naked eye. It can be subdivided into stages.

In the following description of the invention for convenience, the subdivision will be described in six stages, including the case of 0% and the case of 100%. Of course, in some cases, it can be further subdivided, and the contrast can look softer and more natural as the subdivision is made, but in that case, the work time and cost due to subdivision will be proportionate.

In addition, in each division, all points or lines in each step have different sizes or line widths, but the total area of points or the total area of lines included per unit area is set to be the same regardless of the size of individual points and lines.

Then, it is assumed that the point at which copying is possible and the size of the line become the reference point. First, for convenience, the standard unit area is defined as 1 mm ² .

Even if the area of one point where copying is complete is 0.1 mm ² and the area of the point where no copying is made is 0.01 mm ² , if the total area of radiating points and the total area of non-copying points are the same, it can be seen with the naked eye. It achieves the original surface of the same brightness level and density. How many points to put in a unit area can be determined according to the density of the background color. In addition, here, a plurality of points of the same size are normally considered to be equally distributed.

For example, if a single point with an area ^of 0.1 mm ² that is copied is inserted into a unit area, the sum of the areas is 0.1 mm ² . Set the number to 10 so that the sum of the areas of the same points is the same. (Reference formula: 0.01 mm ² x 10 = 0.1 mm ² ). Then, the size of the dots at each stage is subdivided between the two dots of different sizes, and the sum of the areas of the dots created through this is always 0.1 mm ² . If the area of one midpoint is 0.05 mm ² , this point must be placed in 2 units (2 x 0.05 mm ² = 0.1 mm ² ) within the designated area of 1 mm ² .

On the other hand, the dot need not be limited to a circular typical shape. In the present invention, any two-dimensional figure in the form of a closed curve capable of calculating an area such as a point, a line, and a polygon can be used. Whether it is a line or a two-dimensional figure, copy is complete as seen with the naked eye, check the size at a certain standard (width, length of one side, or diameter, etc.) subdivide the size range of .

(Example 1)

As an example, the configuration of the original halftone dots in the copy object subdivided into six according to the original halftone configuration can be organized as shown in the following Table 1, wherein the configuration of the halftone dots is compared with each other as shown in the enlarged view of FIG. so that it can be shown. Here, the size of dots that disappear after copying in a copier (a broad concept including scanners) is a dot with a diameter of 0.05 mm or less, and the size of a dot that is completely reproduced after copying is said to be a dot with a diameter of 0.10 mm or more.

item unit size figure a shortcut mm 0.10 0.09 0.08 0.07 0.06 0.05 Distance between dot centers mm 1.00 0.90 0.80 0.70 0.60 0.50 Dot area (single) mm ² 0.0079 0.0064 0.0050 0.0038 0.0028 0.0020 The number of dots per unit area dog 1.0000 1.2346 1.5625 2.0408 2.7778 4.0000 Dot area per unit area mm ² 0.0079 0.0079 0.0079 0.0079 0.0079 0.0079 Area ratio per unit area % 8.7266 8.7266 8.7266 8.7266 8.7266 8.7266 Dot reproducibility after copying % 100 80 60 40 20 0

0.10 in the first column and the first row of the size numerical column in the table above means the diameter length is 0.10mm, and 1.00mm in the first column and the second row means the distance between the dots in the object and the center of the dot. 0.0079mm ² of a string is the dot area. The area of a single dot is the square of half the diameter of a single dot multiplied by the circumferential rate. In the same way, the first column and the fourth row represent the number of dot per unit area of 1mm ² , the dot area per unit area of the first column and fifth row is the value obtained by multiplying the individual dot area within the unit area by the number per unit area, and the sixth row of the first column The area ratio per unit area of is the ratio (%) of the dot area per unit area for the unit area of 1 mm ² , and the dot recall after copying in the 7th line of the first column is a value measured by a certain standard after actually copying, for example, It can be set as a numerical value of the brightness after a plurality of values compared to the brightness.

Numerical values for the other cells are for objects with different dot diameters, and are measured or calculated in the same way as the values for the first column, so further detailed descriptions will be omitted.

2 and 3 show the visual brightness of an object having halftone dots (original paper on which halftone dots are printed) with the naked eye and the visual brightness of the copy after copying, respectively, as shown in the enlarged view of FIG. 1 . However, the order of the six objects on the drawing is the same in Figs. 1 to 3.

As shown in Table 1, since the total area of halftone dots printed per unit area is the same, the brightness after copying shows different aspects as shown in FIG. It will be possible to decide and plan in advance which halftone dot configuration should be applied to the position and area of the object corresponding to the grade so that the desired image can be expressed after copying.

(Example 2)

As another example, the configuration of the subdivided square dots in the copying object subdivided into six according to the configuration of the square dots can be arranged as shown in Table 2 below. At this time, the configuration of the square dots is compared with each other as shown in the enlarged view of FIG. so that it can be shown. Here, the size of dots that disappear after copying in a copier (a broad concept including scanners) is a dot with a diameter of 0.05 mm or less, and the size of a dot that is completely reproduced after copying is said to be a dot with a diameter of 0.10 mm or more.

comparison unit size figure side length mm 0.10 0.09 0.08 0.07 0.06 0.05 Spacing between dot centers mm 1.00 0.90 0.80 0.70 0.60 0.50 Dot area (single) mm ² 0.0100 0.0081 0.0064 0.0049 0.0036 0.0025 The number of dots per unit area dog 1.0000 1.2346 1.5625 2.0408 2.7778 4.0000 Dot area per unit area mm ² 0.0100 0.0100 0.0100 0.0100 0.0100 0.0100 Area ratio per unit area % 11.1111 11.1111 11.1111 11.1111 11.1111 11.1111 Dot reproducibility after copying % 100 80 60 40 20 0

0.10 in the first column of the size numerical column in the table above means that the length of one side of a square is 0.10mm, and 1.00mm in the first column and second row means the distance between the dots in the object and the center of the dots. , 0.0100mm ² in the third row is the dot area, and the area of a single dot is the square of the length of one side of a single dot. In the same way, the first column and the fourth row represent the number of dot per unit area of 1mm ² , the dot area per unit area of the first column and fifth row is the value obtained by multiplying the individual dot area within the unit area by the number per unit area, and the sixth row of the first column The area ratio per unit area of is the ratio (%) of the dot area per unit area for the unit area of 1 mm ² , and the dot recall after copying in the 7th line of the first column is a value measured by a certain standard after actually copying, for example, It can be set as a numerical value of the brightness after a plurality of values compared to the brightness.

For reference, strictly speaking, since the area ratio (of halftone dots) per unit area in Example 1 is different from the area ratio per unit area in Example 1, it is common that the halftone dot reproducibility after copying is also different, but here is a clear experiment as an example for understanding. It should be considered that the figures are not reflected, and it can be considered that the recall rate according to the shape of each dot may be slightly different depending on how the size of the unit area is determined.

Again, the values for the other cells are for objects with different dot diameters, and are measured or calculated in the same way as the values for the first column, so a detailed description thereof will be omitted.

5 and 6 respectively show the visual brightness of an object having halftone dots (original paper on which halftone dots are printed) as seen in the enlarged view of FIG. 4 and the visual brightness of the copy after copying. Here, the order of the six objects on the drawing is the same in Figs. 4 to 6.

As shown in Table 2, since the total area of halftone dots printed per unit area is the same, even though they appear to have the same brightness as in FIG. 5 with the naked eye, the brightness after copying shows different aspects as shown in FIG. It will be possible to decide and plan in advance which halftone dot configuration should be applied to the position and area of the object corresponding to the grade so that the desired image can be expressed after copying.

More specifically, as shown in the preceding tables and drawings, a circle with a diameter of 0.1 mm or a square with a side length of 0.1 mm is completely reproduced by recognizing the size of the dot during copying, and the length of the diameter is A circle of 0.05 mm or a square with a side length of 0.05 mm disappears because the copier does not recognize the point during copying.

If 4 more steps are set between these two states or two steps, and the dots of each step are subdivided by size and the area ratio of the subdivided points per unit area is the same, the naked eye recognizes all six steps as the same gray color. . When copying, a circle with a diameter of 0.1 mm or a point with a side length of 0.1 mm is reproduced 100% clearly, a circle with a diameter of 0.09 mm or a point with a side length of 0.09 mm is reproduced 80% of the time, and a circle with a diameter of 0.08 mm 60% of points with a side length of 0.08 mm, 40% of circles with a diameter of 0.07 mm or points with a side length of 0.07 mm, 20% of circles with a diameter of 0.06 mm or points with a side length of 0.06 mm, and 20% of points with a diameter of 0.06 mm This circle of 0.05 mm or a point with a side length of 0.05 mm disappears altogether. The figures exemplified above are circles and squares, but almost all polygons or asymmetric figures (ovals, stars, hearts, etc.) can also be used as halftone dots for this invention.

Through this principle, if a picture or picture is changed to black and white and the light and shade are differentiated into six stages to create a picture, they all look gray with the same brightness when viewed with the naked eye before copying, but after copying, differences in light and shade appear according to the reproduction density of each stage. Through this, it is possible to create a picture or image with a contrast level, and through the picture or image, it is possible to perform appropriate processing by making necessary classifications.

(Example 3)

In the above embodiments 1 and 2, circular halftone dots and square halftone dots were used, but the diameter of individual halftone dots or the size of one side was differentiated to enable brightness differentiation during copying. , Example 3 is an example for showing brightness grading through lines.

Fig. 7 is an enlarged view of five types of copy objects having the same printing area ratio per unit area. In the uppermost unit area, 16 line segments, including 8 horizontal segments and 8 vertical segments of the same size, are almost evenly distributed over the entire unit area.

In the unit area below it, two horizontal segments are serially made to make a horizontal segment twice the length, and two vertical segments are serially made to create a vertical segment with twice the length, and in that state they are relatively evenly distributed over the unit area. However, in the evenness of the distribution, it can be said that it is a less even distribution than the topmost one.

In the lower third unit area, one horizontal segment and one vertical segment are combined so that their centers overlap each other to form a + character. However, here, although the printed areas overlap each other at the center, it is considered that the length of the line segment is sufficiently long compared to the line width, and in this case, the overlapped area can be ignored. In this case, the distribution of the +-shaped part printed in the background part, that is, the distribution of the printed area becomes less even and more concentrated compared to the upper two.

Within the second unit area from the bottom, one +-shaped part rotates 45 degrees to the other +-shaped part, and the centers overlap each other, taking a similar shape to a caution sign. As in the previous discussion, the distribution of the printed caution notice type in the background part of such an object, that is, the distribution of the printed area, is less even and more concentrated compared to the upper three.

Within the bottommost unit area, the top caution sign is wrapped in a large rectangular window consisting of two long horizontal lines and two long vertical lines, where the distribution of the printed area is smaller than that of the top four. It becomes an even, more concentrated form.

In the preceding two embodiments, when the printed part is concentrated in a smaller number of dots in a larger area than when it is divided into several smaller areas, it is better recognized during copying and has a high reproducibility, making it appear as a low-brightness area. Each unit area shown in Figure 7 also shows the highest brightness and brightest screen when the uppermost object is copied, and lower brightness and darker screen as it moves downward.

Of course, at this time, as is well known in the art, it is premised that the unit area is set to an area small enough to determine the existence and shape of an accurate point at a glance with the naked eye.

FIG. 8 is exemplary embodiments showing how the copy can be changed in a form in which only a background part with a high brightness and a character printing part with a low brightness, such as a conventional "COPY", can be changed by using the present invention.

The upper example shows an example in which the lightness zone simply goes from left to right and becomes brighter in 6 steps, and the lower example shows an example in which the rectangular zones overlapping each other in a diagonal direction from upper left to lower right show high brightness. It shows a shape that gradually changes from low to low, or from a light area to a dark area.

Of course, various expressions can be applied by applying brightness levels to a plurality of zones other than this embodiment, and a simple black-and-white picture can be actually implemented.

In the above, the present invention has been described through limited examples, but this is only illustratively described to help understanding of the present invention, and the present invention is not limited to these specific examples.

Therefore, those skilled in the art to which the present invention pertains will be able to make various changes or applications based on the present invention, and it is natural that such modifications or applications fall within the scope of the appended claims.

Claims (4)

When copying in the middle of a point or line that appears on a printout when viewed with the naked eye, the minimum diameter or width of a point or line that is copied so that it looks exactly the same as when seen with the naked eye is 100%, and the point or line that cannot be copied at all is called 100%. If the maximum diameter or width is 0%, checking and determining the size or line width of the dots corresponding to 100% and 0%, respectively;
Determining the dot size or line width between 100% and 0% in one or more steps;
Determining which position or area of the print target is to have which printing state level or grade;
A security printing method comprising a step of making a printed matter by printing with dots or lines having a corresponding dot size or a corresponding line width for each location or area of the printing target according to the determined steps. The minimum diameter or width of a point or line that is copied so that it looks exactly the same as when seen with the naked eye when copied in the center of a point or line that appears on a printout by printing when viewed with the naked eye is called a 100% printed state, and a point or line that cannot be copied at all The maximum diameter or width of the line is called the 0% printing state, and when determining a line of a size or line width that can achieve one or more stages of the printing state corresponding to the printing state between the 100% printing state and the 0% printing state, A security print, characterized in that at least three different print states or stages of 100% or less and 0% or more are included in the print. According to claim 2,
The point is a security printout, characterized in that consisting of one or a combination of closed curve two-dimensional figures that can measure the area, including circular, polygonal, and star-shaped. According to claim 2,
The line is a plurality of parallel lines having a certain line width and a certain interval, characterized in that consisting of a straight line or a curve.

Images