DE102007048366A1 - Hidden marking insertion method for printed product, involves applying information on carrier before, during or after printing carrier, and forming structure information such that information is selected with selection unit by moire effect - Google Patents

Abstract

The method involves printing a printing carrier e.g. paper or plastic, for production of a printed product, and applying structure information usable as a hidden marking on the carrier before, during or after printing the carrier. The structure information is formed such that the information is selected with a selection unit e.g. transparent medium such as foil, by a moire effect, where the information in form of Logos and texts. The structure information is applied in a printing process, where the printing process transfers the structure information in form of a raster. An independent claim is also included for a method for visualization of hidden marking.

Description

The The present invention relates to a method for introducing a hidden labeling in a printed product as well as a procedure to visualize the hidden identification.

State of the art:

The moiré effect is manifested by the superposition of rasters or lines through the formation of new lines, comparable to the formation of low-frequency beats, which arise when superimposing similar (sound) frequencies ν ₁ and ν ₂ : ν ₃ = ν ₂ - ν ₁ .

Examples:

Out 1 There are two superimposed line grids which show long-period brightness modulations because the lattice constants differ little from each other.

In the example according to 2 arise Moire structures, because two line grids are rotated with the same lattice constant on each other.

In general, the relationship for the brightness modulation is a ₃ if two gratings with the constants a ₁ and a ₂ are superimposed and rotated by the angle α:

Moire patterns also occur when periodic structures sampled at frequencies which are lower than twice the frequency of the structures. This effect is z. When scanning or rasterizing image data.

The Most reproduction processes (gravure, offset, flexo printing, digital printing) have at least one step along their process chain, in rasterized the supplied data suitable for the output device (RIP). This can lead to the unwanted appearance of moiré patterns come. So is just in the reproduction of fabric samples like Jeans or sports jackets with pronounced almost periodic color modulations (eg herringbone patterns) the occurrence of in the original picture not known structures known.

The so rastered single extracts will be afterwards in the respective color (eg scale colors) printed on each other. Also This can cause the appearance of disturbing Moiré come when for several colors the same grid is used. To remedy this Each single color is created with one of the remaining colors different grid printed on the paper such that the Moiré image resulting from the individual screens used over all Colors of his size stays below the visibility threshold.

Of the Decor printing today is characterized by the fact that marketable decors be copied many times. To make a distinction between original and forgery or to allow a check on already marketed goods, There is a desire to target security features in the decor integrate. At present, corresponding techniques are available for the decorative market unavailable.

task The present invention therefore provides an indication of a method provided with a printed product with a hidden label can be. Furthermore, a method for visualizing a such marking.

This is inventively the requirements 1 and 9 reached. The dependent claims relate to preferred embodiments of the invention.

Brief summary of the present Invention:

It becomes an invisible (security) element (hidden image) in the printed product placed, which, if necessary, taking advantage of the moiré effect again can be read out. The hidden image is in many areas Freely configurable and can be almost any geometrical information record, making this method invisible to others Signing of products and thus for authentication and detection of plagiarism can be used.

in the Within the scope of the present invention, a method will now be described. the mentioned Moire therefor targeted and without disturbing Influence on the print result for the placement of such a security element (Hidden Image). For this purpose, a defined section a single color with a special and original raster this color deviating grid generates such that in the normal Combined printing no negative effects are recognizable. In the print result let yourself then with a suitably structured transparent medium the Difference between the two grids within a single color due to the moire effects that occur to make visible.

In the process of intaglio printing, which is customary in decor printing today, a printing cylinder with the corresponding data must first be imaged in advance. The illustration of the cylinder with two different ones Scattering is only possible if very high-resolution data are written to the cylinder either in a imaging pass, which contain the different raster information as image data, or the cylinders are first provided with the first raster and then with the second raster in a 2-pass process. The first method is currently only possible with the Dätwyler laser, whose only copy is for decor printing at Interprint, or Hell-Gravure-Systems's method of extreme engraving, which has not yet shown its general applicability to this process Has.

2-pass Procedures are for procedural reasons only with non-contact Techniques also make sense of laser technology, the first Not to endanger the imaging step.

It is called a Hidden Image structure information in the form a logo, text or similar on the print carrier z. B. paper or the like applied, such that the information thus introduced means a correspondingly designed transparent medium (foil, plastic, glass) due to the occurring moiré effect can be read out again.

The transfer of the Hidden Image on the print medium can be done with appropriate printing methods that the Transfer information in the form of a grid.

in the Gravure can the structure information z. B. on the engraving on the cylinder be applied such that the normal image information split into two images based on the structure information of the hidden image which is sequentially using various appropriate Grid placed on the cylinder.

Farther Is it possible to process the image information before cylinder production such that the data is finished and according to the structure information provided with different suitable grids. The so processed data will be later in the engraving brought linearly on the cylinder. This method is in a modified form for other types of printing (offset, Digital printing, flexographic printing) in principle applicable.

The Insertion of the Hidden Images can be done in one color alone or in one all colors are done in parallel, so the resulting effect to reinforce.

When print carrier can paper or any other printing material (eg also plastic) serve.

When Readout unit serves a transparent medium, which depends on the pressure is placed. This medium can be made of glass or plastic and should in its dimensions the size of the structural information introduced correspond. Image information is suitably provided on this medium The reading out of the Hidden Image about the moiré effect allow. The image information of this readout medium can, for. B. from fine lines suitable line density or from a corresponding Raster exist.

Claims (12)

Procedure for introducing a hidden marking in a printed product, characterized by the following process steps: - Printing a print carrier to create the printed product; - Apply one as a hidden Marking usable structure information on the print carrier, while or after printing on the print substrate, wherein the structure information is designed such that it with a readout unit using the Moire can be read out again. Method according to claim 1, characterized in that that the structure information in the form of a logo, text or the like applied to the print carrier becomes. Method according to one of claims 1 or 2, characterized that the print carrier Paper or plastic or any other substrate is. Method according to one of claims 1 to 3, characterized that the application of the structure information in a printing process takes place, which transmits the structure information in the form of a grid. Method according to one of claims 1 to 4, characterized in particular in the context of a gravure printing process, the structural information about the Engraving is applied to the cylinder. Method according to one of claims 1 to 5, characterized that in particular in the context of a gravure printing the normal Image information of the pressure based on the structure information of the hidden Label is split into two images, which are sequential put on the cylinder using different rasters become. Method according to one of claims 1 to 6, characterized in that prior to the cylinder production, the normal image information of the pressure is processed in such a way that the image Information corresponding to data ready and provided according to the structure information provided with different suitable grids, wherein preferably the thus prepared data are brought later in the engraving linearly on the cylinder. Method according to one of claims 1 to 7, characterized that the application of structure information in one color alone or in several or all colors used in parallel. Method for visualizing the hidden identification, with a method according to any one of claims 1 to 7 in the printed product was introduced, characterized by the following process steps: - application a readout unit on the printed product, so that the hidden Marking becomes visible. Method according to claim 9, characterized that the readout unit is at least partially transparent Medium is. Method according to claim 10, characterized in that that on or in the transparent medium in a suitable manner image information which are reading out the hidden marking over the Moire allow. Method according to claim 11, characterized in that that on or in the transparent medium or introduced Image information from fine lines of suitable line density or consist of a corresponding grid.