ES3040657A1 - METHOD AND SYSTEM FOR MAKING A MARK ON A SUBSTRATE - Google Patents

Abstract

The present invention relates to a method for making a mark on a substrate by printing a base layer, printing an overlay layer on the base layer, and selectively removing at least a portion of the overlay layer to form the mark, as well as to a marking system configured to make said mark by means of the above method, comprising a printing device and a laser engraving device. (Machine-translation by Google Translate, not legally binding)

Description

DESCRIPTION

METHOD AND SYSTEM FOR MAKING A MARK ON A SUBSTRATE

Object of the invention

The present invention relates to a method for making a mark on a substrate by printing a base layer, printing an overlay layer on the base layer, and selectively removing at least a portion of the overlay layer to form the mark, as well as to a marking system configured to make said mark by means of the above method, comprising a printing device and a laser engraving device.

Background of the invention

In the field of printing and labeling, numerous technologies are known that allow for marking a substrate, for example, to identify a packaged object, to provide relevant information, or as a way to guarantee the origin and quality of a product. These technologies are especially useful in the packaging production and integrated logistics sector, where packaging printing and the application of labels with distinctive signs, logos, symbols, and/or text are extensively used. A widespread technique is the use of self-adhesive labels, which are printed with inkjet printers and affixed to the packaging or directly to the product on the processing line itself, providing great flexibility and efficiency in packaging processing. Printing packaging during its manufacture, prior to distribution and/or assembly, is also common, especially for cardboard packaging.

However, a persistent problem with the aforementioned techniques is the deterioration of the information marked on the product or packaging. The consequences of this can be very serious, ranging from reputational damage due to a damaged logo to health risks for consumers from altered packaging information. More common, however, are errors in reading the labeling, leading to lost products, delays, and other disruptions in the logistics chain. These cases are usually related to barcodes or other similar markings intended for automated reading, which can be damaged by scratches, stains, impacts, or even by the labels being detached, thus preventing the information from being read correctly.

Equally important is the environmental impact associated with self-adhesive labels. These labels are typically printed using specialized printing stations just before being affixed to the packaging. This means that the labels must usually be produced on rolls of standardized dimensions in separate production facilities, then transported to the packaging facilities, supplied to the appropriate labeling station, printed, and affixed to the packaging on the processing line. Furthermore, these label rolls are generally composed of paper fragments with an adhesive layer and a waxed paper backing to hold the labels together and form the roll. The backing material is discarded entirely from each roll, while the labels themselves typically meet the same fate once they reach the end user. Finally, because the labels are produced with standardized dimensions, it is not possible to utilize the entire surface area of the label. Overall, this technique has a considerable environmental impact that should be mitigated as much as possible.

Previously, printing with inks that react to certain types of radiation has also been considered, either applied directly to packaging or to adhesive labels. These inks have a different composition than general-purpose inks, making them more expensive, not only due to their formulation but also because they often involve additional costs resulting from losses during the production process, contamination with cleaning water residue or traces of other inks. This can cause problems during the laser reprinting process and even neutralize the ink's reactivity.

The present invention allows these problems of the state of the art to be overcome effectively, scalably and without compromising the advantages of known techniques in the sector, and in particular it allows dispensing with self-adhesive labels that during the transport process can be damaged or easily peeled off, generating significant losses for the transport sector and customers, as well as avoiding errors in labeling centers using inkjet inks, which can suffer changes in tone during the drying of the ink, or failures in the injectors that generate reading problems.

Description of the invention

The present invention proposes a solution to the above problems by means of a method and a system for making a mark on a substrate, as described below.

In a first inventive aspect, the invention provides a method for making a mark on a substrate by means of a marking system, wherein the marking system comprises:

a printing device configured to apply at least a first ink and a second ink onto a substrate surface, and

a laser engraving device, wherein the laser engraving device comprises a laser source and an engraving head configured to direct a laser beam towards the substrate surface;

The method is characterized by comprising the following stages:

printing on the surface of the substrate, by means of the printing device, a base layer, wherein the base layer is formed by a layer of the first ink, printing on the base layer, by means of the printing device, an overlay layer, wherein the overlay layer is formed by at least one layer of the second ink,

selectively remove, by means of the laser engraving device, at least a part of the overlay layer to make the mark;

where

The first and second inks are water-based inks,

The first ink has a pigmentation of a first color, and the second ink has a pigmentation of a second color, different from the first color.

the base layer has a density of at least 1.5 g/m2, and

The overlay layer has a density of at least 1.5 g/m2.

Throughout this document, it should be understood that applying ink is the deposition of ink onto a substrate surface; specifically, applying ink is the result of a printing process. A substrate, or support, is understood to be a solid material that forms part or all of the item to be marked. For example, the substrate might be cardboard or a cellulose material, such as the cardboard lining a packing box. Other examples might be polymeric materials, and still others, textiles. The substrate comprises at least one surface, preferably a flat, normally visible surface of the item to be marked, that is suitable for applying ink using various printing techniques.

A trademark should be understood as any type of symbol or representation of information, whether for reading and interpretation by a human or in an automated way; preferred examples of trademarks are texts, logos, distinctive signs, alphanumeric codes, linear barcodes, two-dimensional barcodes, matrix codes (e.g., Quick Reaction codes, QR codes), and images.

Ink is understood to be a substantially fluid substance comprising a pigment and a solvent, formulated so that, when applied to a substrate, the pigment adheres to it permanently; a pigment is understood to be the component that provides the pigmentation, or color, to the ink. Furthermore, a water-based ink is understood to be an ink soluble in water.

A layer is understood to be a sheet or film of a material, particularly ink, applied to the surface of a substrate. The layer may cover the entire surface to be marked or only a portion thereof, depending on the marking requirements. As a result, the ink layer, once applied and dry, constitutes a sheet of material with a certain thickness, or more conveniently, a sheet with a certain mass of ink per unit area before selective removal, which in the present invention must be at least 1.5 g/m².

The term "base coat" refers to a layer of ink applied directly to the substrate surface, specifically by means of a conventional printing process. Examples, but not limited to, of suitable printing techniques for applying the ink layer include flexographic printing, offset printing, digital printing, and other printing methods. The term "overcoat" refers to the layer of ink applied immediately over the base coat. The base coat and overcoat may be completely overlapping or partially overlapping. Furthermore, the overcoat may be printed using a single sheet of ink or may consist of multiple layers. Two inks, differing at least in their pigmentation (i.e., the inks have different colors), are used for printing both the base coat and the overcoat.

Selective removal, or ablation, of the overlay layer refers to the controlled removal of a section of ink from the overlay layer by means of a laser engraving device, so that the corresponding section of the base layer is exposed. Preferably, the removed section follows a pattern corresponding to the mark to be made on the substrate.

Advantageously, the process of the invention exposes an observer to a section of the base layer corresponding to a pattern established by the brand, while the negative pattern is represented by the superimposed layer; in this way, and thanks to the difference in pigmentation and the opacity of the layers, sufficient and necessary optical contrast is achieved for the clear and precise perception of the brand, whether by a human observer or by an automatic reading system.

Furthermore, water-based inks offer excellent coverage and transfer properties on any substrate, particularly advantageous on paper and cardboard, as well as good spreadability that guarantees accurate and long-lasting printing, without the need to use inks with other more complex formulations, which are less environmentally friendly and also more likely to produce printing defects.

Advantageously, the proposed method also eliminates the need for self-adhesive labels printed with inkjet technology, as well as the corresponding consumables and substrates, thus contributing to the sustainability and recyclability of the final product. The method can be successfully applied to a wide variety of materials and substrates, limited only by their compatibility with conventional printing systems.

In a preferred embodiment, the step of printing the overlay layer comprises applying two or more layers of the second ink. In another embodiment, the step of printing the base layer comprises applying two or more layers of the second ink.

Advantageously, the application of additional layers allows increasing the density of the layer until the desired opacity is achieved, and consequently the necessary optical contrast.

In a preferred embodiment, the first color is black, and the second color is white. In another embodiment, the first color is white, and the second color is black.

Advantageously, black and white offer optimal optical contrast, so their combination is particularly preferred, either with a black base coat or a white base coat. Other applications utilize different pigment combinations, particularly color combinations with high optical contrast.

In a preferred embodiment, the overlay layer has a density of at least 1.8 g/m2.

Advantageously, the density of 1.8 g/m2 allows for high opacity without overloading the substrate or using more ink than necessary.

In a second inventive aspect, the invention provides a marking system configured to make a mark on a substrate by means of a method according to the first inventive aspect, characterized in that the marking system comprises:

a printing device configured to apply at least a first ink and a second ink onto a substrate surface, and

a laser engraving device, wherein the laser engraving device comprises a laser source and an engraving head configured to direct a laser beam towards the substrate surface.

The marking system shall be understood to comprise a conventional printing device, or flexographic printing press, configured to print at least two inks on the same substrate. A laser engraving device shall be understood to be a conventional device configured to emit a laser beam in a controlled manner, and in particular to emit a laser beam according to a predetermined pattern to obtain a predetermined mark.

In one embodiment, the printing device and the laser engraving device are located in the same installation, and in another embodiment, the printing device and the laser engraving device are located in separate installations, but configured to implement the process of the first inventive aspect.

Advantageously, the marking system allows the implementation of the process that is the subject of the first inventive aspect by means of conventional devices, and adapted for industrialized production of large runs.

In a preferred embodiment, the printing device is a flexographic printing device.

Advantageously, flexographic printing allows for a homogeneous and precise distribution of the ink layer, making it possible to produce an even sharper mark.

In a preferred embodiment, the laser engraving device comprises a CO2 laser source of at least 30 W.

Advantageously, a laser source with a power of 30 W allows the controlled ablation or removal of the overlying layer at a speed sufficient to integrate the process into an industrial production line.

In a preferred embodiment, the laser engraving device comprises a CO2 laser source of at most 100 W.

Advantageously, a laser source with a power of 100 W allows the ablation of the overlay layer very quickly without penetrating the base layer or damaging the substrate.

In a preferred embodiment, the laser engraving device further comprises a second engraving head.

Advantageously, the second engraving head allows for the quick and precise creation of complex, yet clear and easily legible, markings.

These and other features and advantages of the invention will become evident from the description of the preferred, but not exclusive, embodiments, which are illustrated by way of non-limiting example in the accompanying drawings.

Description of the figures

Figs. 1a-1b: These figures show a schematic representation of one implementation of the marking method.

Figs. 2a-2b: These figures show the flowcharts of two preferred embodiments of the method for making a mark.

Fig. 3: This figure shows a preferred embodiment of the marking system.

Detailed description of an example of the invention

The following detailed description presents numerous specific examples to provide a thorough understanding of the relevant teachings. However, it will be evident to those skilled in the subject that these teachings can be put into practice without such details.

In a preferred embodiment of the invention, the marking method is employed to mark a surface of a substrate (6) by means of the marking system (1). In the example shown schematically in Figs. 1a-1b, the mark (7) is a barcode, and the substrate (6) is a conventional corrugated cardboard box intended for packaging a product, being applicable to other materials and other information representations compatible with the invention.

More specifically, Figure 1a schematically and sequentially represents the initial phase of the development of a preferred embodiment of the process implemented by the invention, in which, starting from the cardboard substrate (6) in the form of an unfolded sheet, it is fed into a conventional flexographic printing device (2) in order to print (10) onto the surface of the substrate (6) a base layer (8) of a first ink in the shape of a relatively small rectangle compared to the surface of the substrate (6). Since the mark (7) to be formed is a barcode, it is convenient that the bars be represented in black on a white background; therefore, the base layer (8) must be white, and correspondingly, the overlay layer (9) must be white. Once the base layer (8) has been applied, the substrate (6) must pass through the flexographic printing device (2) again to print (20) the overlay layer (9) onto the base layer (8). This overlay layer (9), also rectangular in shape and approximately the same size as the base layer (8), is printed with white ink. The flexographic printing device (2) must be capable of printing in two colors consecutively. Therefore, it is advisable, but not essential, that the flexographic printing device (2) have at least two ink trays, two anilox rollers, two plate rollers, etc. In other embodiments not shown in the figures, the printing device (2) is an offset printing device or a digital printing device.

As a result of this process, the substrate (6) is obtained with a patch formed by the layers (8, 9) printed on one of its surfaces, which can optionally be die-cut and sent to a packaging facility, for later, as shown in Fig.

1b, be folded and marked by selectively removing (30) by means of the laser engraving device (3), at least a part of the overlay layer (9) according to the pattern required by the barcode, to obtain the mark (7) with an appearance similar to that of a self-adhesive label.

Figure 2a shows the flowchart for the marking method. In this example, the layers (8, 9) each have a minimum density of 1.5 g/m² for the first and second inks, respectively. This is a minimum value, and a density of 1.8 g/m² should preferably be applied, provided the printing device (2) allows it. This density ensures that, regardless of the surface area of the mark (7), the thickness of the ink layer provides sufficient opacity to form a sharp mark (7) with high optical contrast. This is particularly advantageous when the mark (7) is intended for automated reading, for example, in the case of a barcode. After printing the two ink layers (8, 9) consecutively (10, 20), the method requires selective ablation or removal (30) of a portion or section of the overlaid layer (9) by means of the laser engraving device (3). The section to be removed will depend on the desired mark (7), and, for example, for a barcode, vertical bands corresponding to the black bars representing the encoded sequence would need to be removed. An alternative embodiment is shown in Fig. 2b, in which the step of printing (20) the overlay layer (9) comprises applying (21) two or more layers of the second ink successively. In this way, thicker layers, or layers of variable thickness, can be obtained, depending on the marking pattern.

Finally, Figure 3 shows a schematic representation of a preferred embodiment of the marking system (1). In this example, the marking system (1) comprises a conventional flexographic printing device (2) capable of applying two different water-based inks to the substrate (6), and a conventional laser engraving device (3) with a laser source (4) and an engraving head (5). The laser source (4) is the element of the laser engraving device (3) that generates the laser beam, and in this example, it is a CO2 laser source (4) with a power of at least 30 W. Based on the most common ink formulations and densities described above, this power is considered the minimum required to remove the ink layer (30) at a speed acceptable for an industrial process. On the other hand, it is advisable that the power of the laser source (4) not exceed 100 W, in order to prevent damage to the base layer (8) or the substrate (6) during the process. In one specific example, to achieve a marking speed of approximately 4.6 seconds, a laser source (4) with a power of 60 W was used. The engraving head (5) focuses and directs the laser beam onto the substrate surface, specifically onto the overlay layer (9), so that it is successfully removed. To reduce reprinting time, in other embodiments not shown in the figures, a second engraving head (5) can be incorporated, allowing for much higher speeds in production processes.

Clauses of the invention

1. Method for making a mark (7) on a substrate (6) by means of a marking system (1), wherein the marking system (1) comprises:

a printing device (2) configured to apply at least a first ink and a second ink onto a substrate surface (6), and

a laser engraving device (3), wherein the laser engraving device (3) comprises a laser source (4) and an engraving head (5) configured to direct a laser beam towards the substrate surface (6);

The method is characterized by comprising the following stages:

printing (10) on the surface of the substrate (6), by means of the printing device (2), a base layer (8), wherein the base layer (8) is formed by a layer of the first ink,

printing (20) on the base layer (8), by means of the printing device (2), an overlay layer (9), wherein the overlay layer (9) is formed by at least one layer of the second ink,

selectively remove (30) by means of the laser engraving device (3), at least a part of the overlay layer (9) to make the mark (7);

where

The first and second inks are water-based inks,

The first ink has a pigmentation of a first color, and the second ink has a pigmentation of a second color, different from the first color.

the base layer (8) has a density of at least 1.5 g/m2, and

The overlay layer (9) has a density of at least 1.5 g/m2.

2. Method according to the previous clause, wherein the printing device (2) is a flexographic printing device.

3. Method according to any of the above clauses, wherein the step of printing (20) the overlay layer (9) comprises applying (21) two or more layers of the second ink.

4. Method according to any of the above clauses, where the first color is black, and the second color is white.

5. Method according to any of the above clauses, wherein the superimposed layer (9) has a density of at least 1.8 g/m2.

6. Method according to any of the above clauses, wherein the laser engraving device (3) comprises a CO2 laser source (4) of at least 30 W.

7. Method according to any of the above clauses, wherein the laser engraving device (3) comprises a CO2 laser source (4) of at most 100 W.

8. Method according to any of the above clauses, wherein the laser engraving device (3) further comprises a second engraving head (5).

9. Marking system (1) configured to make a mark (7) on a substrate (6) by means of a method according to any of the preceding clauses, characterized in that the marking system (1) comprises:

a printing device (2) configured to apply at least a first ink and a second ink onto a substrate surface (6), and

a laser engraving device (3), wherein the laser engraving device (3) comprises a laser source (4) and an engraving head (5) configured to direct a laser beam towards the surface of the substrate (6).

10. System according to the previous clause, wherein the printing device (2) is a flexographic printing device.

11. System according to any of clauses 9-10, wherein the laser engraving device (3) comprises a CO2 laser source (4) of at least 30 W.

12. System according to any of clauses 9-11, wherein the laser engraving device (3) comprises a CO2 laser source (4) of at most 100 W.

13. Method according to any of clauses 9-12, wherein the laser engraving device (3) further comprises a second engraving head (5).

Claims (13)

1. Method for making a mark (7) on a substrate (6) by means of a marking system (1), wherein the marking system (1) comprises: a printing device (2) configured to apply at least a first ink and a second ink onto a substrate surface (6), and a laser engraving device (3), wherein the laser engraving device (3) comprises a laser source (4) and an engraving head (5) configured to direct a laser beam towards the substrate surface (6); The method is characterized by comprising the following stages: printing (10) on the surface of the substrate (6), by means of the printing device (2), a base layer (8), wherein the base layer (8) is formed by a layer of the first ink, printing (20) on the base layer (8), by means of the printing device (2), an overlay layer (9), wherein the overlay layer (9) is formed by at least one layer of the second ink, selectively remove (30) by means of the laser engraving device (3), at least a part of the overlay layer (9) to make the mark (7); where The first and second inks are water-based inks, The first ink has a pigmentation of a first color, and the second ink has a pigmentation of a second color, different from the first color. the base layer (8) has a density of at least 1.5 g/m2, and The overlay layer (9) has a density of at least 1.5 g/m2. 2. Method according to the preceding claim, wherein the printing device (2) is a flexographic printing device. 3. Method according to any of the preceding claims, wherein the step of printing (20) the overlay layer (9) comprises applying (21) two or more layers of the second ink. 4. Method according to any of the preceding claims, wherein the first color is black, and the second color is white.5 5. Method according to any of the preceding claims, wherein the superimposed layer (9) has a density of at least 1.8 g/m2. 6. Method according to any of the preceding claims, wherein the laser engraving device (3) comprises a CO2 laser source (4) of at least 30 W. 7. Method according to any of the preceding claims, wherein the laser engraving device (3) comprises a CO2 laser source (4) of at most 100 W. 8. Method according to any of the preceding claims, wherein the laser engraving device (3) further comprises a second engraving head (5). 9. Marking system (1) configured to make a mark (7) on a substrate (6) by means of a method according to any of the preceding claims, characterized in that the marking system (1) comprises: a printing device (2) configured to apply at least a first ink and a second ink onto a substrate surface (6), and a laser engraving device (3), wherein the laser engraving device (3) comprises a laser source (4) and an engraving head (5) configured to direct a laser beam towards the surface of the substrate (6). 10. System according to the preceding claim, wherein the printing device (2) is a flexographic printing device. 11. System according to any of claims 9-10, wherein the laser engraving device (3) comprises a CO2 laser source (4) of at least 30 W. 12. System according to any of claims 9-11, wherein the laser engraving device (3) comprises a CO2 laser source (4) of at most 100 W. 13. Method according to any of claims 9-12, wherein the laser engraving device (3) further comprises a second engraving head (5).