DE102015122798A1 - Printed article, method for checking the authenticity of a printed article and article system - Google Patents

Abstract

The invention relates to a printed article (1) having a viewing surface (2) and a printing surface (3) which is arranged in the region of the viewing surface (2), wherein the printing surface (3) is printed with a printing screen (4) the grid points (5) are arranged in each case with a constant dot spacing along grid lines (6), which are each a circular arc. Furthermore, the invention comprises a method for checking the authenticity of a printed article and an article system.

Description

The invention relates to a printed article, a method for checking the authenticity of a printed article and an article system.

background

When printing an article, be it for example a paper document or a passport document in the form of a plastic card, screening technology can be used. The term raster generally designates a regular system of intersecting lines (raster lines) which extend over a region to be printed and along which raster points are arranged as printed elements. In the printing technique, such raster systems are used to reproduce, for example, halftone images. On the surface to be printed a printing grid is printed. The grid points encompassed by the print grid are arranged along the grid lines. The halftone dots may have different dot shapes, such as round or square dot faces. The grid width or grid frequency is the number of grid points per unit length. The smaller the dot pitch between adjacent halftone dots, the larger the screen frequency.

A distinction is made between amplitude-modulated and frequency-modulated grids. In the case of amplitude-modulated printing screens, the halftone dots always have the same distances from one another. The grid points themselves can be different sizes or the same size. In the case of frequency-modulated printed screens, in contrast to the amplitude-modulated screens, the uniformity of the dot distribution is absent. The halftone dots are arranged according to a random distribution, which results in a random distribution of the dot spacings between adjacent halftone dots.

Summary

The object of the invention is to provide improved technologies in connection with the forgery-proof design of printed articles using the halftone printing technique. The authenticity of the printed article should be easily verifiable.

To solve a printed article is provided according to the independent claim 1. Furthermore, a method for checking the authenticity of a printed article according to independent claim 9 and an article system according to independent claim 10 are provided. Alternative embodiments are the subject of dependent subclaims.

In one aspect, there is provided a printed article having a viewing surface and a printing surface disposed in the region of the viewing surface. The printing surface is printed with a printing grid, in which halftone dots are arranged in each case with the same grid spacing along grid lines. The grid lines are each executed as a circular arc.

According to a further aspect, a method for checking the authenticity of a printed article is provided. In the method, a printed article is provided as a specimen, the printed article having in the region of a viewing surface a printing surface which is printed with a printing grid in which halftone dots each having a constant dot spacing are arranged along grid lines, which are each a circular arc. Furthermore, a test means is provided in the method. The test equipment has a transparent test surface with a test printing grid printed thereon, in which screen dots with the same screen pitch as the screen dots of the print screen are arranged on the test piece. The test equipment is placed on the test specimen in such a way that the print grid of the specimen and the test pressure grid of the test equipment overlap. The print screen of the test object and the test pressure grid of the test equipment are shifted relative to one another, for example rotated, until the moire image is visible for the print screen and the test print screen.

In another aspect, there is provided an article system adapted for authenticity testing of the aforesaid kind. The article system has a printed article as well as a test device. In the case of the printed article, a printing surface is arranged in the region of a visible surface and printed with a printing grid in which halftone dots with in each case constant dot or element spacing are arranged along grid lines, which are each a circular arc. The test equipment has a transparent test surface with a test printing grid printed thereon, in which screen dots with the same screen pitch as the screen dots of the print screen are arranged on the printed article.

In the authenticity test, due to the formation of the print raster, a characteristic moiré image is formed, which differs from conventional moiré images and thus makes it possible to test.

The grid points of the print grid can be formed the same or different in terms of their dot shape. The dot shape can be round or angular. For example, a circular shape or a quadrangular shape may be provided. The printing grid can be produced as a monochrome or as a multicolored printing grid.

The printing surface may partially or completely cover the visible surface of the printed article. In the area of the visible surface, a plurality of printing surfaces formed separately from each other can be provided, which are each printed with a printing grid, wherein the printing patterns of the separate printing surfaces can be identical or different. For example, the print patterns in different print areas may differ in the dot pitch along the circular arc grid lines. Alternatively or additionally, for example, the size of the screen dots in the different printing surfaces may be different. The test means can in this case have a plurality of test pressure rasters, which are formed with different screen rulings, wherein the raster widths correspond to the screen widths of the plurality of print rasters. The test equipment with several Prüfdruckrastern different screen ruling can be provided regardless of whether the printed article has multiple printing grid.

In this way, a usable for various printed items test equipment can be provided.

The printed article may be for example a printed document, for example a security document such as a passport or a passport, in particular made of paper or in the form of a plastic card. Alternatively, it can be a paper document, for example a certificate or a certificate. Also, the printed document made of materials other than paper, such as a plastic film or a cardboard material. But also on any other articles, the printing surface can be arranged with the pressure grid arranged thereon. In this case, the printing grid can be printed on a sheet, which is then subsequently attached to the article, for example by means of gluing, which thereby becomes the printed article, ie an article on which the printing surface is arranged with printing grid.

The grid points form the elements of the print grid (grid elements) of any size and shape. The halftone dots can have the same halftone dot size. For example, it may be circular or square grid points of the same size.

For grid points that are on the same grid line, the grid point or grid size may change along the grid line. The grid dot size may increase steadily or continuously along the grid line. The changing halftone dot size can be provided for individual or all grid lines of the print shaver.

The print screen of the article may have a screen ruling in the range of about 100 lpi to about 700 lpi. In this embodiment, the screen ruling corresponds to 100 to 700 lines per inch (lpi).

The printing grid can be printed by means of a sympathetic printing ink. For example, it may be an ink that is visible only when illuminated with UV light.

A tangent to a first point of the arc and a tangent to a second point of the arc may include an angle in the range of about 3 degrees to about 15 degrees, preferably in a range of about 5 degrees to about 10 degrees, the second point of the circular arc along the tangent to the first point has a distance in the range of about 10 cm to about 22 cm from the first point of the circular arc. Alternatively, the distance may be in the range of about 15 cm to about 22 cm.

The print screen can be an amplitude-modulated print screen.

The circular arcs of the print grid can all have the same curvature. Alternatively it can be provided that the circular arcs of the printing grid have different curvatures. For example, a continuous or continuously increasing curvature of the grid lines can be provided via the distribution of the grid lines of the print grid.

In conjunction with the method for checking the authenticity of the printed article and the article system, the embodiments explained above in connection with the printed article may be provided in any desired combination.

In the test pressure grid of the test equipment, the grid points can be arranged along straight grid lines. Alternatively, the grid points may be arranged along curved lines, the curvature of which differs from that of the grid lines of the printed grid to be tested; in particular, another circular arc radius may be provided.

In the method for checking the authenticity of the printed article, an alternative embodiment can provide that a printed article is provided as a test object, wherein the printed article has a printing surface in the region of a viewing surface which is printed with a printing raster along the raster points with a constant dot spacing are arranged by grid lines, which are each a non-straight line, in particular a curved line. Furthermore, in the Method provided a test device. The test equipment has a transparent test surface with a test printing grid printed thereon, in which raster points along raster lines, in particular straight raster lines, are arranged with the same raster width as the raster points of the print raster on the test object. The test equipment is placed on the test specimen in such a way that the print grid of the specimen and the test pressure grid of the test equipment overlap. The printing grid of the test object and the test pressure grid of the test equipment are shifted relative to one another, for example rotated, until a characteristic moiré image is visible for the printing grid and the test printing grid. The characteristic moiré image is also at least different in this case from a resulting moiré image when overlapping printed rasters with straight raster lines each.

In the procedure for checking the authenticity of the printed article, the moiré image, which is produced when the test object and the test equipment are placed on top of each other, can be visible to the naked eye. Alternatively, it may be provided to carry out the authenticity check with the aid of an optical imaging system, for example a camera system with which an image is generated on a screen in order to make the emergence of the moiré image detectable.

In the test equipment, the test print screen may be printed on a transparent substrate, for example a clear plastic film.

Description of exemplary embodiments

In the following, further embodiments will be explained in more detail with reference to figures. Hereby show:

1 a schematic representation of a visible surface of a printed article,

2 an area of a print grid on the visible surface of the printed article 1 .

3 a schematic representation of a section of a Prüfdruckrasters a test means,

4 a schematic representation for explaining a curvature of a raster line and

5 a schematic representation of a test specimen and a test agent.

1 shows a schematic representation of a printed article 1 , in particular a printed document, in which in the area of a visible surface 2 a printing surface 3 is arranged. In the area of the printing area 3 is on the material of the printed article 1 For example, paper or plastic, a printing grid 4 printed. The print grid 4 can be formed in one or more colors. For the printed article 1 For example, it could be a security document such as a passport or a passport. The badge may for example be designed as a plastic or plastic card, optionally as a smart card. Alternatively, the printed article may be 1 to trade a paper document, for example a certificate or a certificate. But on any other article, the printing surface 3 with the pressure grid arranged thereon 4 be arranged. Here, the pressure grid 4 be printed on a sheet, which is then applied later on the article, for example by means of gluing, which thereby becomes the printed article, ie an article on which the printing surface 3 with printing grid 4 is arranged.

2 shows a schematic detail of a portion of the printing surface 3 with the print grid 4 , The print grid 4 has grid points or elements 5 on, which are formed in the illustrated representation with a circular shape. The halftone dots 5 are along gridlines 6 arranged with constant dot spacing. At the grid lines 6 each is a circular arc. In the embodiment shown, the halftone dots have 5 all the same point size.

3 shows a schematic representation of a Prüfdruckrasters 10 with grid points 11 with constant grid spacing or dot spacing along straight grid lines 12 are arranged. The grid width or grid frequency is for the grid points 5 at the printing grid 4 as well as the grid points 11 at the test pressure grid 10 equal. The test pressure grid 10 is printed on a substrate material, which in intermediate areas 13 transparent or transparent. The test pressure grid 10 Can be used to print for the item 1 perform an authenticity check by the test pressure grid 10 as part of a test device, for example a hand bow or a card, over the printing grid 4 is placed. The test pressure grid 10 For example, it may be printed on a transparent film that is part of the test equipment.

The print grid 4 and the test pressure grid 10 can be superimposed on each other during testing relative to each other so that a moiré image for the two rasters, which shows curved line structures, resulting in the combination of the print grid 4 with the circular arc grid lines 6 on the one hand and the test pressure grid 11 with the straight raster lines, wherein the two rasters are formed in the embodiment shown with the same raster. So is the authenticity of the printed article in a simple way 1 determinable with the aid of the test agent on the basis of the characteristic moiré image. It can be checked if the printed article 1 the print grid 4 in fact with the curved grid lines 6 is formed. Here are the grid lines 6 of the print grid 4 a rather slight curvature, which may not even be visible to the naked eye for a less attentive observer.

4 shows a schematic representation for explaining the curvature of a raster line 20 the grid lines designed as a circular arc 6 in the print grid 4 , To a section of the grid line 20 are in a first point or element 21 and a second point or element 22 the respective tangent 23 . 24 created. The tangents 23 . 24 include an angle β that ranges from about 5 degrees to about 10 degrees. The first and the second point 21 . 22 have along the tangent 23 at the first point 21 a distance s. This distance is for example about 10 cm to about 22 cm, alternatively about 15 cm to about 22 cm.

5 shows a schematic representation of an embodiment of a test specimen forming print grid 4 , which is arranged on an article. The print grid 4 is formed with grid points along arcuate raster lines. For comparison, a comparative printing pattern 50 shown in which the grid points are arranged along straight grid lines. Furthermore, a test pressure grid 10 shown on which the grid points are arranged along straight grid lines. The test pressure grid 10 is printed on a transparent foil.

For testing, the test pressure grid 10 on the printing grid 4 and the comparative pressure pattern 50 placed. In the example shown, the screens have a screen width of 70 lpcm (lpcm - lines per cm). By relative displacement of the grid on test specimen and test equipment to each other then arise distinctive moiré images 51 . 52 , When overlaying the print grid 4 with the test pressure grid 10 creates the characteristic moiré image 51 , which is different from the usual moire picture 52 ,

The features disclosed in the above description, the claims and the drawings may be important both individually and in any combination for the realization of the various embodiments.

LIST OF REFERENCE NUMBERS

1

 printed document

2

 viewing area

3

 print area

4

 halftone

5

Grid points of the print grid 4

6

Grid lines of the print grid 4

10

 Prüfdruckraster

11

Grid points of the test pressure grid 10

12

straight grid lines of the test pressure grid 10

13

 between areas

20

 grid line

21

first point on the grid line 20

22

second point on the grid line 20

23

 tangent

24

 tangent

50

 Compare printed screen

51, 52

 Moire images

Claims (10)

Printed article ( 1 ), with a visible surface ( 2 ) and a printing surface ( 3 ), which in the area of the visible surface ( 2 ) is arranged, wherein the pressure surface ( 3 ) with a print grid ( 4 ) is printed at the grid points ( 5 ) with in each case constant dot spacing along grid lines ( 6 ) are arranged, which are each a circular arc. Items ( 1 ) according to claim 1, characterized in that the grid points ( 5 ) of the print grid ( 4 ) have the same grid dot size. Items ( 1 ) according to claim 1, characterized in that for halftone dots ( 5 ), which are on the same grid line ( 6 ), the grid dot size along the grid line ( 6 ) changes. Items ( 1 ) according to at least one of the preceding claims, characterized in that the printing screen ( 4 ) has a screen ruling in a range of about 100 lpi to about 700 lpi. Items ( 1 ) according to at least one of the preceding claims, characterized in that the printing screen ( 4 ) is printed by means of a sympathetic ink. Items ( 1 ) according to at least one of the preceding claims, characterized in that a tangent ( 23 ) to a first point ( 21 ) of the arc and a tangent ( 22 ) to a second point ( 24 ) of the circular arc ( 20 ) include an angle in the range of about 3 degrees to about 15 degrees, preferably in a range of about 5 degrees to about 10 degrees, the second point ( 24 ) of the circular arc ( 20 ) along the tangent ( 23 ) to the first point ( 21 ) a distance in the range of about 10 cm to about 22 cm from the first point ( 21 ) of the circular arc ( 20 ) having. Items ( 1 ) according to at least one of the preceding claims, characterized in that the printing screen ( 4 ) is an amplitude modulated print screen. Items ( 1 ) according to at least one of the preceding claims, characterized in that the circular arcs of the printing grid ( 4 ) all have the same curvature. Method for checking the authenticity of a printed article ( 1 ), in which: - as a test item a printed article ( 1 ) according to at least one of the preceding claims, wherein the printed article ( 1 ) in the area of a visible surface ( 2 ) a printing surface ( 3 ), which with a pressure grid ( 4 ) is printed at the grid points ( 5 ) with in each case constant dot spacing along grid lines ( 6 ) are arranged, which are each a circular arc, - a test means is provided, wherein the test means a transparent test area ( 13 ) with a test printing grid printed thereon ( 10 ) in which halftone dots ( 11 ) with the same screen ruling as the grid points ( 5 ) of the print grid ( 4 ) are arranged on the test specimen, - the test equipment is placed on the specimen, such that the pressure grid ( 4 ) of the test object and the test pressure grid ( 10 ) of the test equipment overlap, and - the print grid ( 4 ) of the test object and the test pressure grid ( 10 ) of the test means are displaced relative to one another until, for the printing grid ( 4 ) and the test pressure grid ( 10 ) a moiré image becomes visible. Article system adapted for authenticity testing according to claim 9 and comprising: - a printed article ( 1 ), which in the area of a visible surface ( 2 ) a printing surface ( 3 ), which with a pressure grid ( 4 ) is printed at the grid points ( 5 ) with in each case constant dot spacing along grid lines ( 6 ) are arranged, which are each a circular arc, and - a test means which a transparent test area ( 13 ) with a test printing grid printed thereon ( 10 ) in which halftone dots ( 11 ) with the same screen ruling as the grid points ( 5 ) of the print grid ( 4 ) on the printed article ( 1 ) are arranged.

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