Method and label printer for manufacturing labels

Abstract

A method for manufacturing labels (20) is described. The method comprises at least the following steps: Generating a printing pattern (40) that defines the printing position of at least one label (20) on a web (16); Generating a cutting pattern (42) that defines a shape and position of at least one cutting line (44) for cutting the at least one label (20) from the web (16); Laser cutting the at least one cutting line (44) with at least one laser to create at least one pre-cut web section (36) and; Printing the at least one label (20) onto the at least one pre-cut web section (36). Furthermore, a label printer is described.

Description

[0001] Method and label printer for manufacturing labels

[0002] The present invention relates to a method for manufacturing labels and a label printer.

[0003] Industrial label printers are known to continuously print material according to a predetermined layout. The material is typically provided as a continuous web to achieve high printing speeds. In order to extract the printed labels, cutting tools are applied subsequent to the printing process. The cutting tools may either be implemented with the printing device or provided in a separate machine.

[0004] In state-of-the-art label manufacturing, die-cutting tools are typically applied to cut the labels from the web. If the label layout is changed, the die-cutting tools have to be adapted and / or exchanged. This results in a downtime of the cutter or even the whole printing machine, which is particularly disadvantageous for small or medium batch size print jobs.

[0005] As an alternative, laser cutting tools have been developed to reduce the tooling time when changing between different printing layouts. However, the job change is still complex and requires significant planning effort and time. Furthermore, laser cutting the printed labels can cause burn marks and gas release.

[0006] Accordingly, there is a need for a means to reduce the overall production effort and to improve the robustness and versatility of industrial label manufacturing.

[0007] The object of the invention is solved by a method for manufacturing labels comprising at least the following steps:

[0008] - Generating a printing pattern that defines the printing position of at least one label on a web;

[0009] - Generating a cutting pattern that defines a shape and position of at least one cutting line for cutting the at least one label from the web;

[0010] Laser cutting the at least one cutting line with at least one laser to create at least one pre-cut web section; and Printing the at least one label onto the at least one pre-cut web section. In this context, “generating a printing pattern” means that the position and / or layout of the at least one label to be printed on the web are defined, in particular virtually and / or as a computer aided design. “Generating a cutting pattern” means that the position and / or layout of the at least one cutting line on the web are defined, in particular virtually and / or as a computer aided design.

[0011] The basic idea of the invention is to carry out the method steps in an order that deviates from a conventional label manufacturing process.

[0012] By laser cutting the at least one cutting line prior to printing, interactions between the print, in particular the printing inks and / or printing colors, and the laser are avoided, thereby preventing burn mark and / or gas formation.

[0013] According to one aspect of the invention, at least one of the method steps is performed while the web is moving.

[0014] By determining the printing position of the at least one label on the web and / or generating the cutting line while the web is moving, the overall planning effort and time for job changes can be reduced.

[0015] In simplified terms, the printing positions and / or cutting lines of the individual labels are defined “on the fly”, for example during a running printing process. This increases the overall manufacturing throughput.

[0016] According to another aspect, the method comprises the further step of recording image data of the at least one laser cut cutting line, for example with an in-line inspection system.

[0017] By capturing and analyzing the image data of the at least one laser cut cutting line, the quality and accuracy of the laser cutting can be verified in real-time, enabling immediate identification of errors or misalignments.

[0018] For example, the positions of further cutting lines to be cut and / or the power of the at least one laser can be adjusted based on the recorded image data of the at least one laser cut cutting line. This dynamic adjustment based on visual feedback allows for compensation of any deviations and / or errors, enhancing the process accuracy and reducing material waste. In one variant, the position of the further cutting lines to be cut and / or the power of the at least one laser are adjusted prior to printing the at least one label onto the at least one pre-cut web section. Making corrections before the actual printing process ensures that subsequent steps operate on optimally prepared material, increasing the overall label quality.

[0019] In another variant, the method comprises the further step of recording image data of the at least one printed label. The image data can then be used to improve the accuracy of subsequent printing or cutting processes.

[0020] For example, the recorded image data is used to generate or adapt the further cutting lines to be cut and / or to define or adapt the position of further labels to be printed. This improves the cutting and / or printing precision and reduces the amount of scrap material.

[0021] In a further variant of the method, the cutting pattern is generated by analyzing a digital print image of the at least one label with an image recognition algorithm. The shape and / or position of the at least one cutting line is for example defined by detecting an edge of the label in the digital print image and by subtracting a margin from the detected edge. It is conceivable that a user supplies the digital print image to the label printer prior to starting a new print job. Alternatively, the digital print image can be obtained from recording image data.

[0022] Automating the definition of the cutting lines to be cut based on the digital print image increases the versatility of the manufacturing process and allows for rapid design changes without manual intervention. In simplified terms, it is not necessary to provide and upload cutting line data to the label printer in order to set up a new printing job. This reduces the effort and time for print job changes and increases the overall production yield and throughput.

[0023] In an exemplary embodiment, the at least one label is printed with a surrounding margin area, wherein an edge of the margin area is detected by analyzing the recorded image data with the image recognition algorithm. Further cutting lines to be cut are for example generated and / or adapted based on the detected edge.

[0024] The edge detected by the image recognition algorithm is preferably the outer edge of the margin area. According to another aspect, the image recognition algorithm is applied to detect a colored background of the at least one label in the digital print image. From this information, the shape of the at least one label and thus the correct layout and position of the cutting lines can be determined with high reliability.

[0025] To reduce the amount of waste material, the at least one cutting line is for example defined such that the at least one label is enclosed by the at least one cutting line with a margin of less than 3 mm, for example with a margin in the range between 0.5 mm and 3 mm. It has been found, that, in contrast to diecutting, a distance of less than 3 mm is sufficient to achieve a good cutting quality and edge precision of the cut labels. The small cutting margin reduces material consumption, increasing the yield and decreasing the amount of waste per label.

[0026] In another variant of the method, the at least one label is printed without a margin area. In this case, the edge of the label’s digital print image can be detected with the image algorithm and the at least one cutting line can be generated such that it is congruent to the detected edge of the label. This allows to reduce the amount of waste material even further.

[0027] According to another aspect, the at least one cutting line is defined by detecting a characteristic feature in the digital print image and by retrieving information about the shape and / or size of the at least one label from a database based on the detected characteristic feature. Retrieving data about the label and applying it to generate the cutting pattern reduces the risk of errors, for example due to incomplete or incorrect edge detection with the image recognition algorithm.

[0028] The characteristic feature is for example a barcode characterizing a product intended to be labeled with at least one of the labels. The barcode is an important element of many labels and can be analyzed with state-of-the-art technology. Printing of an additional characteristic feature for the sole purpose of retrieving information about the label shape is not necessary.

[0029] It is furthermore conceivable that the at least one cutting line is defined by predicting the symmetry of the at least one label from the digital print image. This is particularly useful to correctly define the cutting lines for labels with a symmetrically shaped edge but asymmetric color distribution. For example, the cutting line for a circular label with a colored background extending over only half of the circle can be generated by detecting the edge of the colored half circle (which is easily possible with an image analysis tool) and subsequently determining the edge of the non-colored half based on an assumed symmetry of the label.

[0030] In another variant of the method, a machine learning algorithm is applied to generate the printing pattern and / or the cutting pattern. In particular, the machine learning algorithm can be applied to determine the printing position of the at least one label on the web and / or to generate the at least one cutting line. This improves the overall process automation and results in a continuously increasing printing and cutting accuracy and thus label quality.

[0031] In another exemplary embodiment, the printing position for the at least one label is determined or adapted based on recorded image data of previously printed labels. This improves the process control in general and enables a more efficient use of the available web space.

[0032] In a further variant of the method, different labels are printed, wherein the different labels are grouped into different print jobs. For example, in a first print job, circular labels are printed and in a second job, square-shaped labels are printed on the web.

[0033] The printing positions for the individual labels are for example determined by nesting the different print jobs on the web. In other words, the different print jobs are arranged on the web dependent on one another, which allows a very efficient use of the available web space.

[0034] In one variant of the method, the print jobs are nested while the web is moving and / or while a printing process is running. This decreases the overall planning time and effort required for job changes.

[0035] In a technically easy to implement embodiment, the at least two different print jobs are simultaneously printed in different lanes of the web.

[0036] Alternatively, the at least two different print jobs can be printed simultaneously or subsequently in one lane to further improve the utilization of the available web space. To improve the process control, a change between the at least two different print jobs can be detected by analyzing recorded image data of the printed labels. The gathered information can then be used to ensure generation and / or application of cutting lines matching precisely with the respective labels and / or for planning the nesting of the next print job.

[0037] The object of the invention is also solved by a label printer comprising a cutting station with at least one laser configured to laser cut a moving web to create at least one pre-cut web section, a printing station configured to print at least one label on the pre-cut web section, and a control unit configured to perform a method according to the invention.

[0038] The advantages that were discussed for the method also apply for the label printer.

[0039] Further advantages and features will become apparent from the following description of the invention and from the appended figures, which show a nonlimiting exemplary embodiment of the invention and in which:

[0040] Fig. 1 schematically shows a side view of a label printer according to a first embodiment of the invention;

[0041] Fig. 2 schematically shows a side view of a label printer according to a second embodiment of the invention;

[0042] Fig. 3 schematically shows a section of a web during the manufacturing of the labels with the label printer shown in Fig. 1; and

[0043] Fig. 4 schematically shows a label with a margin area printed with the label printer shown in Fig. 1.

[0044] Fig. 1 shows a schematic drawing of an industrial label printer 10 configured as a Roll-to-Roll machine.

[0045] The label printer 10 comprises an input stage 12 and an output stage 14. At the input stage 12, a roll of processing material in the form of a web 16 is provided. The web 16 is processed between the input stage 12 and the output stage 14. At the output stage 14, a roll of finished material is collected.

[0046] Alternatively, the finished material may be collected at the output stage 14 as a stack of individual print products.

[0047] The label printer 10 furthermore comprises a printing station 18 located between the input stage 12 and the output stage 14, and a cutting station 22 located between the printing station 18 and the output stage 14.

[0048] The printing station 18 is configured to print labels 20 on the passing web 16, for example by inkjet or flexographic printing.

[0049] The cutting station 22 is configured to cut the printed labels 20 from the web 16. For this purpose, it is equipped with two lasers 24.

[0050] Of course, the label printer 10 can comprise further optional stages and / or stations, for example a cleaning stage 26 configured to remove particles from the web 16 prior to printing, a web motion controller 28 configured to control and / or align the movement of the web 16 and / or a matrix rewinder 30.

[0051] The label printer 10 shown in Fig. 1 furthermore comprises an inspection station 32 located between the printing station 18 and the cutting station 22. The inspection station 32 is configured to record and to analyze image data of the labels 20 printed on the passing web 16.

[0052] The label printer 10 furthermore comprises a control unit 34, for example a computer, configured to run software codes that cause the printing station 18 to print labels 20 on the web 16 and / or the cutting station 22 to cut the labels 20 from the web 16.

[0053] The label printer 10 shown in Fig. 1 can be operated in a first operation mode, in which labels 20 are printed on the web 16 with the printing station 18 and subsequently cut from the web 16 with the cutting station 22. The web direction in the first operation mode is indicated with an arrow in Fig. 1.

[0054] Furthermore, the label printer 10 shown in Fig. 1 can be operated in a second operation mode, in which the labels 20 are printed subsequent to the cutting process. This can be achieved by changing the web path or by running the web 16 in reverse direction. When operated in the second operation mode, the web 16 first passes the cutting station 22 with the lasers 24. The lasers 24 are configured to laser cut the moving web 16 to create pre-cut web sections (not shown in Fig. 1).

[0055] After laser cutting, the web 16 moves to the printing station 18, which is configured to print labels 20 on the pre-cut web sections.

[0056] Fig. 2 schematically shows a side view of a label printer 10 according to a second embodiment of the invention. The label printer 10 shown in Fig. 2 corresponds in several essential aspects to the label printer 10 shown in Fig. 1. Hence, only the differences will be discussed. Identical and / or functionally identical components are provided with the same reference numbers.

[0057] In contrast to the label printer 10 shown in Fig. 1, the cutting station 22 of the label printer 10 shown in Fig. 2 is located between the input stage 12 and the printing station 18.

[0058] Furthermore, the label printer 10 shown in Fig. 2 comprises two inspection stations 32. One inspection station 32 is located between the cutting station 22 and the printing station 18 and configured to record image data of pre-cut web sections 36 created by the lasers 24. Another inspection station 32 is located between the printing station 18 and the output stage 14 and configured to record image data of printed labels 20.

[0059] Of course, the setup and arrangement of the individual stations shown in Figs. 1 and 2 is only exemplary and not to be understood limiting to the invention.

[0060] The control unit 34 of the label printer 10 shown in Fig. 1 as well as the control unit 34 of the label printer 10 shown in Fig. 2 are each configured to control the respective label printer 10 such that it performs a method for manufacturing labels 20. The individual steps of the method are discussed in the following with reference to Fig. 3.

[0061] Fig. 3 schematically shows a section of a web 16 during the manufacturing of the labels 20.

[0062] Pre-cut web sections 36, which correspond to labels 20 that are yet to be printed, are drawn with dashed lines, while the already printed labels 20 are drawn with solid lines. In a first step S1 of the method, the control unit 34 generates a printing pattern 40 that defines the printing positions for the individual labels 20 of a print job 38 on the web 16.

[0063] In a second step S2 of the method, the control unit 34 generates a cutting pattern 42 that defines the shapes and positions of multiple cutting lines 44, in particular for laser cutting the web 16 in order to create the pre-cut web sections 36.

[0064] The shape and / or size of the cutting lines 44 can be defined by the label printer 10 based on a digital print image of the labels 20. Alternatively, cutting line data can be supplied by a user, in particular as computer aided design.

[0065] In a third step S3 of the method, the control unit 34 drives the lasers 24 such that they laser the cutting lines 44 to create the pre-cut web sections 36.

[0066] In a fourth step S4 of the method, the control unit 34 drives the printing station 18 such that it prints the labels 20 onto the pre-cut web sections 36.

[0067] Steps S1 and S2, S3 and / or S4 of the method are preferably performed while the web 16 is moving, in particular while a print job 38 is running.

[0068] By laser cutting the cutting lines 44 prior to printing, burning and / or evaporation of printed inks or colors by the laser 24 is avoided.

[0069] The method furthermore comprises the optional step of recording image data of the laser cut cutting lines 44 with the inspection station 32 located between the cutting station 22 and the printing station 18.

[0070] Based on the recorded image data, the positions of further cutting lines 44 to be cut and / or the power of the lasers 24 can be adjusted to improve the cutting quality.

[0071] Preferably, the image data of the laser cut cutting lines 44 is recorded prior to printing the labels 20 on the corresponding pre-cut web sections 36 to facilitate the analysis of the recorded image data.

[0072] In addition, image data of the printed labels 20 can be recorded with the inspection station 32. This image data is for example used to determine the printing accuracy and alignment. If an offset between the pre-cut web sections 36 and the printed labels 20 is detected, the printing positions of the following labels 20 and / or the cutting positions of the further cutting lines 44 to be cut can be adjusted. In other words, the labels 20 yet to be printed and / or the cutting lines 44 yet to be cut can be arranged and / or shifted on the web 16 depending on the previously printed labels 20 and / or previously laser cut cutting lines 44. This allows a highly efficient use of the available web space and enables a fast correction of errors and adaptation to changes in the printing layout.

[0073] As illustrated in Fig. 3, different types of labels 20 with different layouts can be manufactured, the different labels 20 being grouped in different print jobs 38.

[0074] The printing positions for the individual labels 20 of each of the print jobs 38 are determined by nesting the different print jobs 38 on the web 16. For example, a new print job 38 can be nested depending on a previously printed print job 38.

[0075] As shown in Fig. 3, the web 16 is split into two different lanes 46. For each of the lanes 46 the print jobs 38 can be nested individually.

[0076] To continuously improve the nesting of the print jobs 38 on the web 16 and / or the determination of suitable printing positions for the individual labels 20, a machine learning algorithm is applied. The machine learning algorithm is for example configured to analyze the recorded image data of previously printed labels 20 and to determine the nesting and / or printing positions such that the available web space is most efficiently used.

[0077] In general, the different labels 20 and / or print jobs 38 can be printed simultaneously in the different lanes 46, subsequently in the same lane 46 and / or subsequently in the different lanes 46 of the web 16.

[0078] Each of the lasers 24 is for example associated with one of the lanes 46 such that it lasers only the cutting lines 44 for the labels 20 located in the respective lane 46.

[0079] It is conceivable that the web 16 is not fully cut through when generating the pre-cut web sections 36. In particular, the web 16 can comprise a carrier layer for carrying the labels 20 that is not cut by the lasers 24. After printing, the labels 20 are for example separated from a matrix 48 of the web 16. The matrix 48 can then be removed from the labels 20 and / or carrier layer and collected with the matrix rewinder 30.

[0080] In the following, several further details and aspects of the printing procedure and cutting line generation of the label manufacturing process are described with reference to Fig. 4, which shows a digital print image of a label 20.

[0081] The digital print image is for example uploaded to the label printer 10 prior to starting a new print job 38 and used to automatically generate a virtual image of the cutting line 44, in particular as a computer aided design.

[0082] To ensure a time efficient manufacturing process, the control unit 34 generates the cutting pattern 42 and / or the virtual image of the cutting line 44 while the web 16 is moving, in particular, while a preceding print job 38 is running.

[0083] Optionally, the control unit 34 can detect print job changes, for example by analyzing the recorded image data, and adjust the shape of the cutting line 44 to be laser cut accordingly.

[0084] One half 50 of the label 20 shown in Fig. 4 has a colored background. The other half 52 has an uncolored and / or white background.

[0085] To define the size and shape of the cutting line 44 for the label 20 shown in Fig. 4, the control unit 34 analyzes the digital print image with an image recognition algorithm to detect an outer edge 54 of the label 20. For this purpose, a machine learning algorithm can be applied.

[0086] Based on a result of the analysis, a virtual image of the cutting line 44 can be generated such that it encloses the label 20 with a distance between the cutting line 44 and edge 54 being less than 3 mm.

[0087] In other words, the shape and size of the cutting line 44 is defined based on the detected edge 54, in particular by subtracting a margin 56 from the edge 54, the margin 56 being between 0 mm and 3 mm.

[0088] If the outer edge 54 cannot be fully detected, the virtual image of the cutting line 44 can be generated based on symmetry considerations. For example, the shape and size of the cutting line 44 for cutting the label 20 shown in Fig. 4 is defined by detecting the outer edge 54 of the colored half 50 of the label 20 in the digital print image, mirroring said detected edge 54 and subsequently subtracting the margin 56.

[0089] Of course, it is also possible to simultaneously or subsequently print multiple labels 20. In this case, it is sufficient to generate a virtual image of the cutting line 44 only once. The virtual image can be reproduced or repeatedly applied to generate the cutting pattern 42 and / or to laser the web 16 in order to create the pre-cut web sections 36.

[0090] After laser cutting the pre-cut web sections 36, the labels 20 are printed with a surrounding margin area 58. The margin area 58 is a part of the matrix 48 surrounding the label 20. Preferably, the margin area 58 is printed in the colors of the label 20 to avoid the occurrence of uncolored label edges in case of minor imprecisions during the cutting or printing process.

[0091] After printing, image data of the label 20 can be recorded to check the printing quality and alignment.

[0092] The recorded image data can further be used to adapt the printing pattern 40 and / or cutting pattern 42. In particular, the shape or size of the cutting lines 44 can be adapted or new cutting lines 44 can be generated by detecting the edge 54 and / or predicting the symmetry of the label 20 based on the recorded image data.

[0093] For example, after printing the label 20 shown in Fig. 4, image data of the print is recorded with the inspection station 32. The image data can then be analyzed by the control unit 34, in particular by applying an image recognition algorithm, to detect the printed colored half 50 of the label 20 and to adapt the cutting line 44 or to generate a new cutting line 44 for the entire label 20 (including the uncolored half 52) based on a known or predicted symmetry of the label 20. For this purpose, a machine learning algorithm can be applied.

[0094] Alternatively or additionally, the cutting line 44 can be generated by detecting a characteristic feature 60 of at least one of the labels 20 in the digital print image or the recorded image data and by retrieving information about the shape of said label 20 from a database based on the detected characteristic feature 60. As shown in Fig. 4, the characteristic feature 60 is for example a barcode 62 characterizing a product intended to be labeled with the label 20, or more precisely, an image of the barcode 62 comprised by the digital print image or recorded image data.

[0095] The control unit 34 can analyze the characteristic feature 60, in particular the recorded barcode 62, by applying state-of-the-art technology to retrieve data about the label shape and / or further manufacturing relevant information for the respective label(s) 20.

[0096] Gathering and using such information decreases the risk of generating cutting lines 44 that do not match with the labels 20 to be printed and thus the risk of producing reject labels and / or scrap material.

Claims

Claims1. A method for manufacturing labels (20) comprising at least the following steps:Generating a printing pattern (40) that defines the printing position of at least one label (20) on a web (16);Generating a cutting pattern (42) that defines a shape and position of at least one cutting line (44) for cutting the at least one label (20) from the web (16);Laser cutting the at least one cutting line (44) with at least one laser (24) to create at least one pre-cut web section (36); andPrinting the at least one label (20) onto the at least one pre-cut web section (36).

2. The method according to claim 1 comprising the further step of recording image data of the at least one laser cut cutting line (44).

3. The method according to claim 2, wherein the positions of further cutting lines (44) to be cut and / or the power of the at least one laser (24) are adjusted based on the recorded image data of the at least one laser cut cutting line (44).

4. The method according to claim 3, wherein the position of the further cutting lines (44) to be cut and / or the power of the at least one laser (24) are adjusted prior to printing the at least one label (20) onto the at least one pre-cut web section (36).

5. The method according to any one of the preceding claims comprising the further step of recording image data of the at least one printed label (20).

6. The method according to claim 5, wherein the position of further cutting lines (44) to be cut and / or the position of further labels (20) to be printed are adjusted based on the recorded image data of the at least one printed label (20).

7. The method according to any one of the preceding claims, wherein the cutting pattern (42) is generated by analyzing a digital print image of the at least one label (20) with an image recognition algorithm, wherein the shape and / orposition of the at least one cutting line (44) is defined by detecting an edge (54) of the digital print image and by subtracting a margin (56) from the detected edge (54).

8. The method according to claim 7, wherein the at least one cutting line (44) is defined such that the at least one label (20) is enclosed by the at least one cutting line (44) with a margin (56) of less than 3 mm.

9. The method according to claim 7 or 8, wherein the at least one cutting line (44) is defined by detecting a characteristic feature (60) in the digital print image and by retrieving information about the shape of the at least one label (20) from a database based on the detected characteristic feature (60).

10. The method according to any one of the claims 7 to 9, wherein the at least one cutting line (44) is defined by predicting the symmetry of the at least one label (20) from the digital print image.

11. The method according to any one of the preceding claims, wherein a machine-learning algorithm is applied to generate the printing pattern (40) and / or the cutting pattern (42).

12. The method according to any of the preceding claims, wherein different labels (20) are printed, the different labels (20) being grouped into different print jobs (38).

13. The method according to claim 12, wherein the printing positions for the labels (20) are determined by nesting the different print jobs (38) on the web (16) while the web (16) is moving.

14. The method according to claim 12 or 13, wherein at least two different print jobs (38) are simultaneously printed in different lanes (46) of the web (16).

15. A label printer comprisinga cutting station (22) with at least one laser (24) configured to laser cut a moving web (16) to create at least one pre-cut web section (36),a printing station (18) configured to print at least one label (20) on the pre-cut web section (36), and- 16 -a control unit (34) configured to perform a method according to any one of the preceding claims.

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