Printed optimized security element

Abstract

A method for printing a document (2, 4) with security elements, the method being implemented by two separate computer-aided systems, wherein the systems comprise a printing system (9) and a security system (12), the printing system having a printing press, the method comprising the steps of: creating, by a computer of the security system (12), a document with placeholders (14, 7) for the security elements in image data and sending the document into the printing system (9); converting, by a computer of the printing system (9), the image data into an output color space of the printing press and sending the document (15, 17, 10) into the security system (12); generating, by a computer of the security system (12), the security elements and replacing the placeholders with the security elements and sending the document (2, 4) into the printing system (9); printing, by the printing press of the printing system (9), the final document (13) with the security elements.

Description

TECHNICAL FIELD

[0001] The present invention relates to a method for generating a print-optimized security element.

[0002] The present invention belongs to the field of security printing. BACKGROUND

[0003] For security reasons, security features are generated in closed systems, in particular security features in which a masked image, in particular a hidden image, is used. In the prior art solutions, the generation software and the test software come from the same company. Since most solutions using masked images do not have any knowledge about a specific printing process, but must produce the masked image in a later process coloration, the image data is converted into the CMYK color space by means of a neutral ICC profile, for example ISO coated v3, and the security element is generated on a corresponding color separation. Here, the test software expects the hidden structure as it has been produced. However, in the case of a deviation of the printing material or a different color system, in particular in a digital printing press using CMYKOGV instead of CMYK as process colors, with a corresponding shift of the color positions of the primary colors, this can only be ensured under certain conditions or only with a partial significant color deviation.

[0004] Then, different problems arise in the prior art. For example:

[0005] a) In the case of a maintained pre-given color separation, a significant color deviation with respect to the designed color appearance can result, and thus a non-sellable printed product.

[0006] b) In the color conversion, for example from CMYK to CMYKOGV, the security element can not be readable, thus no longer providing protection.

[0007] c) In the case of a deviation of the color system, only the initially set color separation, but not all existing color separations, are used for the security element.

[0008] To this end, only the following solution has been known to date: an attempt is made to prevent the destruction of the security element due to the color conversion by maintaining the set color separation.

[0009] International patent application WO 2005 / 122010 Al further provides a method and a system for processing within a RIP and for printing variable documents. The method of the invention comprises creating a page description language file (PDL file) defining fixed and variable elements and a data file defining the variable elements of the mechanism and processing the PDL file in a raster image processor (RIP) in combination with the data file in order to render the variable document into the image memory of a digital output device. The invention further comprises transforming the variable elements according to algorithms contained in the PDL file. In another aspect the method comprises an In-RIP-Appli- cation (In-RIP-Auferlegen) of a plurality of mechanisms of a variable document. In this aspect the PDL file comprises one loop or a series of nested loops which are processed to render one or more mechanisms of the variable document. The system of the invention comprises a software application capable of generating the PDL file and the data file according to the invention, a RIP capable of processing the PDL file in combination with the data file, and a digital output device connected to the RIP and capable of printing the document according to the invention. SUMMARY

[0010] It is therefore the task of the present invention to disclose a method for generating a print-optimized security element, in which the color stability of the security element is ensured in the case of a conversion of the security element into a different color space.

[0011] The task is solved by a method for printing a document with security elements, which is carried out by two separate computer-aided systems, wherein the computer-aided systems comprise a printing system with a printing machine and a security system, the method comprising the following steps: creating a document with placeholders for the security elements in the image data by a computer of the security system and sending the document into the printing system; converting the image data into the output color space of the printing machine by a computer of the printing system and sending the document into the security system; generating the security elements and replacing the placeholders with the security elements by a computer of the security system and sending the document into the printing system; printing the final document with the security elements by the printing machine of the printing system. Here, in order to solve the problem of converting the security elements into a different color space and the color information loss occurring therein, which impairs the effectiveness of the security elements, it is essential that the image data of the document to be printed are converted into the output color space of the printing machine with the placeholders at first. Then, when the printing system has converted the image data accordingly, the printing system sends these image data back to the security system with information about the characterization data to be used by the printing machine for the printing process. Then, the security system can generate the security elements in the correct color space and replace the placeholders with them by means of these information. Then, the final document is sent to the printing system, which can complete the printing of the final document in the output color space of the respective printing machine by means of its printing machine.

[0012] Advantageous and therefore preferred extensions of the method result from the preferred embodiments and from the description with the aid of the enclosed drawings.

[0013] Here, a preferred extension of the method according to the invention is that the placeholders in the document are created by the security system in the form of a description of the security elements to be used later. By this it is ensured that when converting the image data of the document into the output color space of the printing machine, the printing system already has as much data about the document to be printed later as possible in order to thus be able to achieve as accurate a conversion as possible by means of the output color space.

[0014] Here, a further preferred extension of the method according to the application is that the computer of the security system sets a first security key for the placeholder, in particular in the form of an OAuth2 token, jointly with the document, wherein the first security key is deactivated when converting the image data into the output color space, then the computer of the printing system activates the first security key, creates and activates a second security key for the entire document and sends the document with both security keys to the computer of the security system, which checks the validity of both security keys and replaces the placeholder with the generated security element in the event of validity. The use of two security keys is necessary in order to ensure that the two image data in the form of the placeholder and the document cannot be changed by themselves other than by the two authorized agencies of the security system and the printing system. After all, the security elements must only be used in the printed objects, for example banknotes or specific certificates, which correspond to the respective security key. Therefore, the security system checks the validity of both security elements when obtaining the document converted into the output color space and replaces the placeholder with the generated security element only in the affirmative case, then the document is sent back to the printing system thus authorized and authenticated.

[0015] Here, a further preferred extension of the method according to the application is that a hidden image is used as a security element. The method according to the application is also suitable for using other types of security elements. However, hidden images are primarily used.

[0016] Here, a further preferred extension of the method according to the application is that an inkjet printer is used as a printing machine, the output color space of which is the CMYKOGV color space. It is equally applicable here that the method according to the application can also be used for other types of printing machines and other color spaces. However, the main application case of the application relates to inkjet printers, which use the CMYKOGV color space in the preferred embodiment.

[0017] Here, a further preferred extension of the method according to the application is that the computer of the printing system and the computer of the security system send the document via a secure data channel. By this, the security of the entire method can be further improved in addition to the use of security keys for the placeholder and the document. It is less important for the method according to the application in which form the security of the data channel is ensured. The security of the data channel can be achieved by different types of encryption algorithms or also by secure channels, for example VPNs, or similar technologies.

[0018] In this case, a further preferred extension of the method according to the application is that the computer of the security system requests a matching ICC profile at the computer of the printing system or at a third institution in the case of a later specification of the printing conditions, wherein in the case of a third institution the computer of the security system then sends the ICC profile to the computer of the printing system, and the computer of the printing system then converts the image data into the output color space of the printing press by means of the ICC profile. The specification of the later printing conditions in the form of characterization data describing the printing process can be implemented, for example, in the form of an ICC profile. However, in this case the security system must be able to cope with ICC profiles accordingly and also be able to process them. However, since ICC profiles are a widely used means of describing the printing process of a specific printing press in terms of conversion into the output color space, this means is preferably applied here. In principle, however, other types of specification of the later printing conditions can also be used as characterization data. BRIEF DESCRIPTION OF DRAWINGS

[0019] The application itself and advantageous extensions of the application, structurally and / or functionally, are further described below with reference to at least one preferred embodiment with reference to the accompanying drawings. In the drawings, elements corresponding to one another are provided with the same reference signs, respectively.

[0020] The drawings show:

[0021] Figure 1 The flow of the method according to the application in its preferred embodiment is shown;

[0022] Figure 2 The flow of the method according to the application in a first alternative embodiment is shown;

[0023] Figure 3 The flow of the method according to the application in a second alternative embodiment is shown. DETAILED DESCRIPTION

[0024] Figure 1 The flow of the method according to the application in its preferred embodiment is shown schematically, wherein the order of the method steps is from a) to 1). In the first step, the file to be protected as original document 1 is only provided with a description of the later security coding (as a hidden image) and a security key (for example in the form of an OAuth2 token) in the coding software (security application 12). These documents are used in the normal design process in a manner with placeholders for the security elements, the corresponding design documents are created and output as PDFs 16 with placeholders for the security elements. During this time, the security key for the final embedding of the security coding (hidden image) is deactivated.

[0025] Within the scope of the printing job, a further security key is set to the PDF 16 and the security key for the final embedding of the security coding (hidden image) is activated, but only valid in combination with the security key of the PDF 16.

[0026] In processing the document, one or more elements with the planned security coding are extracted after the color separation by the color conversion application 6 into the output color space, further processed by the renderer 5 into a color space converted PDF 17 with placeholders for the security elements, and then the thus obtained color space converted image file 15 with placeholders for the security elements is sent back into the encoding software 12 via a secure channel. The encoding software checks the validity of the two security keys and, if valid, generates an image file 2 with the set security coding (hidden image). The image file 2 set with the security coding is sent back into the production system 9 and replaced in the production system 9 for the printing output 13.

[0027] Then, production continues as planned.

[0028] By using the content separated for the planned printing process, the used color separation matches the actual printing process. Since the printing process is increasingly often also switched between different output technologies (e.g. offset and / or digital output technology), the color impression and the function of the security elements can only be guaranteed by generating and embedding the security elements during the printing process. This brings the advantage that in the proposed method the security elements remain unimpaired as hidden images and are only affected by the calibration to a minimal extent. Furthermore, the color reproduction accuracy is guaranteed even in the case of a change in the output technology.

[0029] In addition to the preferred embodiments described, other alternative variants can also be envisaged. Thus, Figure 2A first alternative is shown in the form that in the case of an improved separation according to a print database and a separate color conversion software (print data application 8), the generation is carried out directly in the security application as coding software 12. In this variant, the security application 12 interrogates the matching ICC profile 18 in the case of the later-mentioned print conditions 11 and the security application sends the unprocessed original document with ICC table 7 to the color conversion application 6, which separates the original document 7 according to the predefined ICC profile 18 and attaches the ICC profile 18 to the original document 7. The color space-converted image file 10 thus separated is then sent back into the security application 12. Now, the file 10 is provided with a security coding (hidden image) and is further processed by the design application 3 to an output PDF with hidden image 4, which is then rendered by the renderer 5 into a ready-to-print state. In the printout 13 with hidden image 4 thus obtained, the achievable color accuracy can now be checked according to the ICC profile 18.

[0030] Figure 3 A further alternative embodiment is disclosed. Here, the core is that the generation is carried out directly in the security application 12 in the case of an improved separation by means of a production system 9, which comprises a print data application 8 including a print database and a color conversion software 6. In this variant, the security application 12 interrogates the production system 9 in the case of the later-mentioned print conditions, which determines the matching ICC profile 18 and separates the original document with ICC table 7 according to the predefined ICC profile 18 and attaches the ICC profile 18 to the file. The color space-separated image file 10 is then also sent back into the security application 12. The file 10 is then provided with a security coding (hidden image) and is further processed as in Figure 2

[0031] The disadvantage of both alternative embodiments is that in the case of a wrongly chosen planned printing process, large color deviations can still occur.

[0032] List of reference signs

[0033] 1 original document

[0034] 2 image file with hidden image

[0035] 3 design application

[0036] 4 PDF with hidden image ​

[0037] 5 renderer

[0038] 6 color conversion application

[0039] 7 original document with ICC profile

[0040] 8 print data application

[0041] 9 production system including a printing press

[0042] 10 color space converted image file

[0043] 11 description of a print condition

[0044] 12 security application

[0045] 13 finished printed product

[0046] 14 image file with placeholder for security element

[0047] 15 color space converted image file with placeholder for security element

[0048] 16 PDF with placeholder for security element

[0049] 17 color space converted PDF with placeholder for security element

[0050] 18 ICC profile

Claims

1. A method for printing a document (2, 4) with a security element, the method being carried out by two separate computer-aided systems, wherein, The computer-aided system comprises a printing system (9) having a printing press and a security system (12), the method comprising the following steps: • creating a document with placeholders (14, 7) for security elements in the image data by a computer of the security system (12) and sending the document into the printing system (9); • converting the image data into the output color space of the printing press by a computer of the printing system (9) and sending the document (15, 17, 10) into the security system (12); • generating the security elements and replacing the placeholders by the security elements by a computer of the security system (12) and sending the document (2, 4) into the printing system (9); • printing a final document (13) with the security elements by a printing press of the printing system (9).

2. The method according to claim 1, characterized in that the placeholders in the document are created by the security system (12) in the form of a description (11) of the security elements to be used later.

3. The method according to claim 1 or 2, characterized in that the computer of the security system (12) sets a first security key for the placeholders together with the document (14, 7), wherein the first security key is deactivated when converting the image data into the output color space, then the computer of the printing system (9) activates the first security key, creates and activates a second security key for the entire document and sends the document with both security keys into the computer of the security system (12), which checks the validity of both security keys and replaces the placeholders by the generated security elements if valid.

4. The method according to claim 1 or 2, characterized in that a hidden image is used as security element.

5. The method according to claim 1 or 2, characterized in that an inkjet printing press is used as printing press, the output color space of which is the CMYKOGV color space.

6. The method according to claim 1 or 2, characterized in that the computers of the printing system (9) and of the security system (12) send the documents (2, 4, 7, 13, 14, 15, 17) via a secure data channel.

7. The method according to claim 1 or 2, characterized in that the computer of the security system (12) requests a matching ICC profile (18) at the computer of the printing system (9) or at a third institution in case of a specification of later printing conditions (11), wherein in case of the third institution the computer of the security system (12) then sends this ICC profile (18) into the computer of the printing system (9), then the computer of the printing system (9) converts the image data into the output color space of the printing press by means of this ICC profile (18).

8. The method according to claim 3, characterized in that The first security key is in the form of an OAuth2 token. The first security key is in the form of an OAuth2 token.

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