Labeling device, in particular in beverage filling plant, comprising current meter for evaluating labels

Abstract

The invention relates to a labeling device having a current meter with which a label to be applied is evaluated and which reacts to anomalies during continuous operation by adjusting an intervention in order to ensure a desired labeling result.

Description

Technical Field

[0001] The invention relates to a labeling device having an ammeter, with which a label to be applied is evaluated. Background Art

[0002] In particular when water-based adhesives are used, the water absorption of labels applied by labeling devices can be evaluated, in particular in beverage filling equipment. Thus, US2006 / 124239 A describes a wet glue labeling, which contains a liquid adhesive for fixing a label to a container. Shortly before the label is attached to the object to be labeled, such as a bottle, the wet adhesive is applied to the label. For optimal application of the label, the so-called Cobb value (water absorption of paper) is determined. For example, the Cobb value can be determined according to DIN53121 (August 2014). The Cobb value is a measure of water absorption and is used to determine the balance between adhesion and rapid application and secure positioning of the label, because, for example, it can be used to determine the relevant process parameters of the amount or type of adhesive to be used.

[0003] However, it has been shown that determining the Cobb value is not always sufficient to ensure a consistent quality of labelling. In particular, in the case of fluctuating quality of the label material, a prior determination of the Cobb value is not sufficient to ensure trouble-free labelling. At the same time, it has been shown that the determination of the Cobb value is not always sufficient to predict the actual behaviour of the label during the bonding process.

[0004] Therefore, a more precise method is needed to predict the labelling behaviour of labels during the gluing process, in particular with water-based adhesives (e.g. applied by spraying). In this case, this possibility should also be implemented in particular during the continuous operation of the labelling device, in order to obtain measurement results during continuous operation that allow direct intervention in the labelling method, for example by adjusting the type or amount of adhesive. Summary of the invention

[0005] Surprisingly, the above mentioned problems can be solved if the ammeter measurement is carried out on the tag. The present invention is based on this finding. DETAILED DESCRIPTION

[0006] For example, the tag can be subjected to an ammeter measurement according to the measurement procedure described in GB 403304 A. The information obtained by this measurement, similar to the determination of the Cobb value, is a measure of the permeation behavior of the tag to water, which has proven to be a more accurate (but at the same time easy to perform) type of determination of the relevant information of the tag to be used in the context of the present invention.

[0007] The information obtained by means of an ammeter measurement allows a more precise control of the labeling process, since the information obtained in this way predicts the actual behavior of the label during bonding with the water-based adhesive in the labeling device better than the Cobb value. In the ammeter measurement, in particular, the rate at which water (and therefore also the water-based adhesive) penetrates into the label can be determined precisely and at the same time quickly. This measured value allows a precise control or regulation of the labeling process. In particular, when the quality of the label material changes (which also occurs in a given label batch), the labeling process can quickly adapt to changes in the label quality.

[0008] In the context of the present invention, the quality of the labeling, ie in particular the precise and permanent positioning of the label, can therefore be ensured taking into account the measured values ​​measured by the ammeter.

[0009] To this end, for example, during the continuous operation of the labeling device, ammeter measurements can be continuously performed on the labels. For example, the labeling device can be connected to the ammeter measuring station in such a way that in each case one thousandth of the labels, for example three thousandths of the labels, are branched off from the continuous supply of labels to the labeling device and are fed to the ammeter measuring station. The information obtained by the ammeter measurement can then flow back to the control or regulation device of the labeling device in order to achieve an adaptation of the adhesive amount or adhesive composition, for example when determining a change in the measured value of the ammeter measurement. Thus, a more precise and better control of the labeling result can be achieved compared to the determination of the Cobb value.

[0010] However, in the context of the present invention, it is of course possible and preferred in an embodiment if the determination of the Cobb value is also carried out in addition to the ammeter measurement. This can basically be integrated into the labeling device in a similar manner. Therefore, in addition to the ammeter measuring station, the labeling device of the present invention can also have a measuring station for determining the Cobb value. Likewise, for this purpose, during continuous operation, the desired number of labels can be branched from the label supply to the labeling device and supplied to the measuring station for determining the Cobb value. The labeling device of the present invention then also has the necessary devices for branching the labels so that these labels are then supplied to the measuring station for determining the Cobb value, just as in the case of the ammeter measurement. The information obtained when determining the Cobb value supplementing the ammeter measurement results can then flow again into the control or regulation device of the labeling process.

[0011] Finally, the labeling device can also be combined with a device for determining the Cobb value or have a device for determining the bending stiffness of the labels separately. For this purpose, too, during continuous operation, the desired number of labels can be branched off from the label supply to the labeling device and fed to the measuring station for the determination of the bending stiffness. The labeling device of the invention then also has the necessary means for branching off the labels so that these labels are then fed to the measuring station for the determination of the bending stiffness, just as in the case of the ammeter measurement. The information obtained when determining the bending stiffness, which supplements the ammeter measurement results, can then flow again into the control or regulation device of the labeling process.

[0012] As described above, the present invention provides the results of the ammeter measurement as a measure for determining the quality of the label (i.e., in particular its suitability for use in a labeling device using a water-based adhesive, in particular in a high-speed labeling process of spraying adhesive). It has been found that if the label exhibits a fast permeation behavior with respect to water, which can be quantified by the time curve of the increase in the measured value during the ammeter measurement, the label is particularly suitable for use in this method.

[0013] Therefore, in the context of the present invention, it has been specifically determined that this suitability can be determined not only qualitatively / relatively (a fast increase in measured value is better than a slow increase in measured value) but also quantitatively by the increase in measured value in the ammeter measurement defined below.

[0014] To this end, the increase in current intensity during the measurement from the start time to the current intensity value of 0.9 mA is determined by measuring the time required to reach a current intensity of 0.1 to 0.9 mA (in steps of 0.1 mA) (as described herein, the measured value at time 0 seconds (start of measurement) is 0 mA).

[0015] High-quality labels, i.e. those suitable for use without problems in the above-mentioned high-speed labeling process, are characterized by an increase in the current during the ammeter check, wherein a current intensity of 0.7 mA is reached within a period of 30 seconds or less, preferably 20 seconds or less, in an embodiment of about 15 seconds. In this case, a curve of increasing current intensity is preferred, wherein a measured value of 0.1 mA is reached after 15 seconds or less, preferably 10 seconds or less, for example about 5 seconds, and a measured value of 0.5 mA is reached after 20 seconds or less, preferably 15 seconds or less, for example about 10 seconds.

[0016] It has been found that during this process of increasing the current intensity, the labels, regardless of the type of label (printed, metallized, etc.), are very suitable for high-speed labeling devices with spraying of water-based adhesives (i.e. good adhesion, low tendency of the edges or corners of the label to bulge or slide). Thus, the present invention shows that labels whose current intensity is increased very quickly for the first time to 0.1 mA and whose current intensity is then increased still quickly but slowly can be used very well for the labeling method described herein.

[0017] If, in addition to the ammeter measurement, the Cobb value and / or the bending stiffness of the label are determined, the measured values ​​obtained thereby can likewise be used for evaluating the label and thus for controlling or regulating the labeling process.

[0018] It has been found, in conjunction with the results of the ammeter measurements, that such labels are particularly suitable for use in high-speed labeling devices with a bending stiffness in the range of 0.1 to 0.01 Nmm, preferably in the range of 0.75 to 0.05 Nmm. In principle, with regard to bending stiffness, lower values ​​are advantageous in the context of the present invention.

[0019] With regard to the Cobb value determined after 60 seconds as described herein, it should preferably be in the range of 10 to 80 g / m2, with values ​​in the higher range being preferred.

[0020] Therefore, labels which are particularly preferred and suitable for use in the labelling apparatus described herein preferably exhibit a short penetration time relative to water (measured by an ammeter) and at the same time have a low bending stiffness value and a (relatively) high Cobb value.

[0021] Such labels are therefore particularly suitable for labelling plants which spray water-based adhesives and ensure a high-quality labelling process. In principle, the knowledge provided by the invention about the penetration behaviour (amperometric measurement) as well as the target values ​​for the bending stiffness and the Cobb value enables a simple and at the same time very precise evaluation of the labels, if necessary even before actual use in the labelling process. Thus, in particular in the case of metallized labels, the basic suitability for use in labels can already be tested on samples and, if necessary, modifications can be made in the event of deviations from the desired values, for example with regard to the thickness of the label, the substrate (type of paper), the number and material of the intermediate layers etc.

[0022] In particular, it can be provided that the invention can also be used to apply adhesive by a glue roller (conventional labeling) instead of spraying. Therefore, the labeling device can have a glue roller for applying adhesive and / or have the above-mentioned device (nozzle) for spraying.

[0023] The labels to be evaluated in the context of the present invention are labels having at least one layer of paper. The labels can be printed, have metallized layers, and can also be multilayer structures. Such additional layers can be polymer layers, varnish layers, intermediate layers for improving the adhesion of different layers in multilayer labels, protective layers, etc.

[0024] The ammeter measurement, and optionally the determination of the Cobb value, is carried out on the side of the label (paper layer) which is provided with the adhesive and applied to the object to be labeled. In a preferred embodiment, the bending stiffness of the label can be additionally determined as a third parameter. Thus, in this particularly preferred embodiment, a total of three parameters are determined on the label to be used, namely the ammeter measurement, the determination of the Cobb value and the determination of the bending stiffness.

[0025] As mentioned above, the adhesive for labeling is preferably a water-based adhesive, which is directly applied to the label or the surface of the object to be labeled by spraying in the labeling device. This spraying can be carried out through a nozzle, similar to an ink printing process.

[0026] It has been found that high quality labelling can be achieved for a wide range of different labels (plain paper labels, printed paper labels, metallised paper labels) when the rate at which water penetrates into the label is determined by an ammeter and the information obtained therefrom is used in labelling.

[0027] Therefore, the present invention also provides a method for quality control of labels, wherein the method comprises an ammeter measurement, optionally combined with the determination of the Cobb value and / or the determination of the bending stiffness on the label. This quality control also allows the labeling process to be checked and controlled, because when the parameters described and determined here are known (the results of the ammeter measurement, the Cobb value and / or the bending stiffness), the labeling process can be adjusted / controlled based on these parameters. By storing such measurement results in combination with the corresponding labeling behavior and relevant additional information of the labeling process (adhesive used, amount of adhesive applied, type of object to be labeled, other parameters such as temperature and humidity, etc.), an information library can be generated, which, when using an appropriate system, can lead to a self-learning system for controlling and regulating the labeling process. Therefore, if necessary, a stable labeling process can be set up more quickly, thereby reducing waste when starting the labeling process.

[0028] In this case, the ammeter measurement determines in particular the speed with which water penetrates into the label. This information is an essential factor for control and regulation in a labeling device in which the labels are applied to the object to be labeled using a water-based adhesive. The person skilled in the art will understand here, as well as with regard to the above-described labeling device, that the labels evaluated are not used for labeling (these labels are discarded after the corresponding measurement), but that the information obtained during the measurement is considered to be representative of the remaining labels in a set of labels. These remaining labels are fed to the labeling process and the information obtained by the measurement is used to control and regulate the labeling process. All preferred embodiments described above with the labeling device according to the invention also apply in an analogous manner to the method described herein.

[0029] Measurement method:

[0030] Cobb value: ISO 535:2014

[0031] Bending stiffness: DIN 53121

[0032] Amperemeter measurement: A square sample (50×50 mm) is cut from a label conditioned at 23° C. and 55+5% relative humidity for at least 16 hours. The first electrode of the ammeter is placed on the sample holder and 0.2 ml of deionized water is added to it. The sample is then placed with the unprinted side on the water drop. The second electrode of the ammeter is then placed on the other side of the sample. The measurement starts with the contact of the second electrode with the sample. The measurements are taken in intervals of 0.05 mA (the time elapsed in mA to reach the corresponding value).

Claims

1. A labelling device, in particular in a beverage filling plant, comprising an ammeter measuring station for evaluating labels.

2. The labeling device according to claim 1, wherein: The labels are applied to the object to be labeled using a water-based adhesive.

3. A labelling device according to any one of the preceding claims, wherein: During ongoing operation, tags are automatically fed to the ammeter measuring station at regular intervals.

4. A labelling device according to any one of the preceding claims, wherein: The labeling device further comprises a measuring station for determining the Cobb value of the label and / or a measuring station for determining the bending stiffness of the label.

5. The labeling device according to claim 4, wherein: During ongoing operation, labels are automatically fed to the measuring station at defined intervals for determination of the Cobb value and / or the bending stiffness.

6. A labelling device according to any one of the preceding claims, wherein: The label is an unprinted paper label, a printed paper label or a metallized paper label.

7. A labelling device according to any one of the preceding claims, wherein: The application of the adhesive is achieved by spraying onto the label or the object to be labeled.

8. A labelling device according to any one of the preceding claims, wherein: The results of the ammeter measurement and optionally the results of the Cobb value determination and / or the bending stiffness determination are used to control or regulate the labeling process, for example by adapting the composition of the adhesive used.

9. A method for quality control of labels, wherein: The method includes taking an ammeter measurement of the tag.

10. The method according to claim 9, wherein: The method further comprises determining the Cobb value and / or determining the bending stiffness on the label.