WO2017108035A1 - 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), comprising a visible surface (2) and a printed surface (3), arranged in the region of the visible surface (2), wherein the printed surface (3) is printed with a halftone (4), wherein halftone dots (5) are arranged at a respective consistent distance along halftone lines (6), each of which is an arc. The invention also relates to a method for checking the authenticity of a printed article and an article system.

Description

 Printed article, method for checking the authenticity

 a printed article and article system

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

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. A printing grid is printed on the surface to be 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. Document GB 1,138,011 A discloses printing patterns with dots, for example banknotes. In one embodiment, halftone dots are arranged on closed circular arcs. The document EP 1 127 712 A1 discloses a security and / or value document, in particular a banknote, with security features and with a verification element for verifying the security feature.

Document EP 0 279 526 A2 discloses a security document.

Document DE 699 17 947 T2 relates to a method and apparatus for authenticating documents by applying the intensity profile of Moire patterns.

Composition

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 grid points are arranged with constant 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 test object, wherein the printed article has a printing surface in the region of a visible surface, which is printed with a printing grid in which halftone dots each having the same dot spacing are arranged along grid lines, each one circular arc are. 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 test specimen's printing grid and the test printing grid of the test specimen overlap. The printing grid of the test piece and the test pressure grid of the test equipment are shifted relative to one another, for example rotated, until the moire image becomes visible for the printing screen and the test printing 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 print 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, a characteristic Moire image is formed due to the formation of the print raster, which differs from conventional Moire images and thus allows an examination.

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 separately formed pressure surfaces can be provided, which are each printed with a printing grid, wherein the pressure grid 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 may be different in the different printing surfaces. In this case, the test equipment can have a plurality of test pressure rasters which are formed with different raster widths, the raster widths corresponding to the raster 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 print grid can 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 Druckffäche is arranged with printing grid.

The grid lines of the print grid can extend along a circular arc, such that the grid lines and thus also the grid points arranged along the grid line are not arranged on a closed circle. The circular arc in the printing grid is not part of a set of multiple circular arcs that together form a (closed) circle in the 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 print grid have differing curvatures. point. 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, the printed article having in the region of a viewing surface a printing surface which is printed with a printing raster along the raster points with a constant dot spacing in each case are arranged by grid lines, which are each a non-straight line, in particular a curved line. 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 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 piece and the test pressure grid of the test equipment are shifted relative to one another, for example twisted, 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 specimen and test equipment are placed on top of each other, can be visible to the naked eye. AI Alternatively, it can 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 moiri 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 EMBODIMENTS In the following, further exemplary embodiments will be explained in more detail with reference to FIGS. Hereby show:

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

2 shows a region of a print raster on the visible surface of the printed article from FIG. 1, FIG. 3 shows a schematic representation of a detail of a test pressure raster of an inspection medium,

 4 shows a schematic representation for explaining a curvature of a raster line, and FIG. 5 shows a schematic representation of a test object and a test device.

1 shows a schematic representation of a printed article 1, in particular a printed document, in which a printing surface 3 is arranged in the region of a visible surface 2. In the area of the printing surface 3, a printing screen 4 is printed on the material of the printed article 1, for example paper or plastic. The printing grid 4 can be formed in one or more colors. For example, the printed article 1 may 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 1 may be a paper document, such as a certificate or a certificate. But also on any other articles, the printing surface 3 may be arranged with the pressure grid 4 arranged thereon. Here, the printing grid 4 can be printed on a sheet, which is then applied later on the article, for example by means of Sticking, which thereby becomes the printed article, ie an article on which the printing surface 3 is arranged with printing grid 4.

2 shows a schematic detail of a section of the printing surface 3 with the printing screen 4. The printing screen 4 has screen dots or elements 5, which are formed in the illustration shown with a circular shape. The grid points 5 are arranged along grid lines 6 with constant dot spacing. The grid lines 6 are each a circular arc. In the embodiment shown, the screen dots 5 all have the same dot size.

FIG. 3 shows a schematic representation of a test pressure grid 10 with grid points 11, which are arranged with constant grid dot spacing or dot spacing along straight grid lines 12. The raster width or raster frequency is the same for the raster points 5 in the printing raster 4 and the raster points 11 in the test printing raster 10. The Prüfdruckraster 10 is printed on a substrate material which is transparent or transparent in intermediate areas 13. The Prüfdruckraster 10 can be used to perform an authenticity check for the printed article 1 by the Prüfdruckraster 10 is placed as part of a test means, such as a handbow or a card on the print grid 4. The test printing grid 10 may be printed, for example, on a transparent film which is part of the test device.

The printing grid 4 and the Prüfdruckraster 10 can be superimposed when checking 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 Prüfdruckrasters 11 with the straight grid lines, the two rasters are formed in the embodiment shown with the same screen width. Thus, the authenticity of the printed article 1 can be determined in a simple manner with the aid of the test device on the basis of the characteristic Moire image. It can be checked whether in the printed article 1, the printing grid 4 is actually formed with the curved grid lines 6. In this case, the grid lines 6 of the printing grid 4 have a rather small curvature, which for a less attentive viewer may not be recognizable to the naked eye.

4 shows a schematic illustration for explaining the curvature of a raster line 20 of the raster lines 6 embodied as a circular arc in the printing raster 4. At a section of the raster line 20 in a first point or element 21 and a second point or element 22 the respective tangent 23, 24 created. The tangents 23, 24 enclose an angle β which is in a range of about 5 degrees to about 10 degrees. The first and second points 21, 22 have a distance s along the tangent 23 to the first point 21. This distance is, for example, about 10 cm to about 22 cm, alternatively about 15 cm to about 22 cm.

Fig. 5 shows a schematic representation of an embodiment of a test specimen forming print grid 4, which is arranged on an article. The printing grid 4 is formed with grid points along circular arc-shaped grid lines. For comparison, a comparison printing pattern 50 is shown in which the screen dots are arranged along straight raster lines. Furthermore, a Prüfdruckraster 10 is shown, on which the grid points along straight grid lines are arranged. The Prüfdruckraster 10 is printed on a transparent film.

To test the Prüfdruckraster 10 is placed on the print grid 4 and the comparison printing pattern 50. In the example shown, the screens have a screen width of 70 lpcm (lpcm - lines per cm). By Relatiwerlagerung the grid on the test piece and test equipment to each other then arise differing moire images 51, 52. When superimposing the print grid 4 with the Prüfdruckraster 10 results in the characteristic Moire image 51, which is different from the usual Moire image 52nd

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. Reference numeral

1 printed document

 2 visible surface

 3 printing area

 4 printing grid

 5 grid points of the print grid 4

 6 grid lines of the print grid 4

 10 test pressure grid

 11 grid points of the test pressure grid 10

12 straight grid lines of the test pressure grid 10

13 intermediate 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 comparative pressure grid

 51, 52 moire pictures

Claims

Expectations Printed article (1), with a visible surface (2) and a printing surface (3) in the area of the visible surface (2) is arranged, the printing surface (3) is printed with a printing grid (4), in which grid points (5) are arranged with a constant dot spacing along grid lines (6), each of which is a circular arc. Article (1) according to claim 1, characterized in that the grid points (5) of the printing grid (4) have the same grid dot size. Article (1) according to claim 1, characterized in that for grid points (5), which lie on the same grid line (6), the grid dot size varies along the grid line (6) changes. Article (1) according to at least one of the preceding claims, characterized in that the printing screen (4) has a screen width in a range from approximately 100 lpi to approximately 700 lpi. Article (1) according to at least one of the preceding claims, characterized in that the printing grid (4) is printed using a sympathetic ink. Article (1) according to at least one of the preceding claims, characterized in that a tangent (23) to a first point (21) of the circular arc and a tangent (22) to a second point (24) of the circular arc (20). Include angles in the range of about 3 degrees to about 15 degrees, preferably in a range of about 5 degrees to about 10 degrees, with the second point (24) of the circular arc (20) along the tangent (23) to the first point ( 21) has a distance in the range of approximately 10 cm to approximately 22 cm from the first point (21) of the circular arc (20). 7. Article (1) according to at least one of the preceding claims, characterized in that the printing grid (4) is an amplitude-modulated printing grid. 8. Article (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. 9. Procedure for checking the authenticity of a printed article (1) in which: ~ a printed article (1) according to at least one of the preceding claims is provided as a test specimen, wherein the printed article (1) is in the area of a visible surface (2) has a printing surface (3) which is printed with a printing grid (4), in which grid dots (5) are arranged with the same dot spacing along grid lines (6), each of which is a circular arc, - a test means is provided, the test means having a transparent test surface (13) with a test print grid (10) printed thereon, in which grid points (11) with the same grid width as the grid points (5) of the print grid (4) are arranged on the test specimen are, » the test equipment is placed on the test item in such a way that the pressure grid (4) of the test piece and the test pressure grid (10) of the test equipment overlap, and « the print grid (4) of the test object and the test print grid (10) of the test equipment are moved relative to one another until a moiré image becomes visible for the print grid (4) and the test print grid (10). 10. Article system prepared for an authenticity check according to claim 9 and comprising: > a printed article (1), which has a printing surface in the area of a visible surface (2). (3), which is printed with a printing grid (4), in which grid dots (5) are arranged with the same dot spacing along grid lines (6), each of which is a circular arc, and - A test device which has a transparent test surface (13) with a test print grid (10) printed thereon, in which grid points (11) have the same grid width how the grid dots (5) of the printing grid (4) are arranged on the printed article (1).