EP-4735261-A1 - LASER CODER AND METHOD OF OPERATION

Abstract

There is provided a laser coder, the laser coder comprising, a housing, a laser source disposed within the housing, the laser source configured to generate a laser beam, a laser beam steering assembly disposed within the housing, the laser beam steering assembly configured to steer the laser beam to an address within a two-dimensional marking field to create marks on a film substrate provided at a marking location adjacent to the housing, a detector configured to generate image data comprising an image of the film substrate, and a controller configured to: receive first image data comprising a first image of the film substrate when the film substrate is in a first position, receive second image data comprising a second image of the film substrate when the film substrate is in a second position, the film substrate having been advanced along a film substrate path in a first direction from the first position to the second position, identify a difference between the first image data and second image data, generate an address within the two-dimensional marking field based on the identified difference and a reference address within the two-dimensional marking field, and execute a marking operation to mark the film substrate using the address.

Inventors

• Kueckendahl, Peter J.

Assignees

• ALLTEC ANGEWANDTE LASERLICHT TECHNOLOGIE GMBH

Dates

Publication Date

20260506

Application Date

20240627

Claims (20)

1. CLAIMS: 1 A laser coder, the laser coder comprising: a housing; a laser source disposed within the housing, the laser source configured to generate a laser beam; a laser beam steering assembly disposed within the housing, the laser beam steering assembly configured to steer the laser beam to an address within a two- dimensional marking field to create marks on a film substrate provided at a marking location adjacent to the housing; a detector configured to generate image data comprising an image of the film substrate; and a controller configured to: receive first image data comprising a first image of the film substrate when the film substrate is in a first position; receive second image data comprising a second image of the film substrate when the film substrate is in a second position, the film substrate having been advanced along a film substrate path in a first direction from the first position to the second position; identify a difference between the first image data and second image data; generate an address within the two-dimensional marking field based on the identified difference and a reference address within the two-dimensional marking field; and execute a marking operation to mark the film substrate using the address.
2. 2. The laser coder according to claim 1 , wherein the controller being configured to identify the difference between the first image data and second image data comprises the controller being configured to; identify an offset between the first image and the second image, the offset indicating an offset distance in a second direction perpendicular to the first direction.
3. 3. The laser coder according to claim 2, wherein the controller being configured to identify the offset between the first image and the second image, comprises the controller being configured to: identify a location of a first edge in the first image, the first edge parallel to the first direction; identify a location of a second edge in the second image, the second edge corresponding to the first edge; identify the offset based on comparing the locations of the first edge and second edge.
4. 4. The laser coder according to claim 3, wherein the controller being configured to identify the location of the first edge in the first image, comprises the controller being configured to: convert the first image into a first one-dimensional array, where each value in the first one-dimensional array represents a combination of pixel values along a first axis of the first image, the first axis parallel to the first direction; identify the first edge in the first one-dimensional array; identify the first location of the first edge in the first one-dimensional array.
5. 5. The laser coder according to claim 3 or 4, wherein the controller being configured to identify the location of the second edge in the second image, comprises the controller being configured to: convert the second image into a second one-dimensional array, where each value in the second one-dimensional array represents a combination of pixel values along a first axis of the second image, the first axis parallel to the first direction; identify the second edge in the second one-dimensional array; identify the second location of the second edge in the second onedimensional array.
6. 6. The laser coder according to any of claims 2 to 5, wherein the controller being configured to generate the address within the two-dimensional marking field based on the identified difference and the reference address within the two-dimensional marking field comprises the controller being configured to: apply the offset to the reference address to generate the address.
7. 7. The laser coder according to claim 6, wherein the controller being configured to apply the offset to the reference address to generate the address comprises the controller being configured to: add the offset distance to a value of a coordinate of the reference address that specifies a position along the second direction.
8. 8. The laser coder according to any preceding claim, wherein the controller is further configured to: receive advancement data, the advancement data indicative of a state of advancement of the film substrate along the film substrate path, and wherein the controller being configured to execute the marking operation using the address further comprises the controller being configured to: execute the marking operation to mark the film substrate using the address and the advancement data.
9. 9. The laser coder according to any preceding claim 8, wherein the second image data comprises a plurality of images of the film substrate when the film substrate is in a plurality of positions, wherein the controller is further configured to generate an average of the plurality of images to obtain the second image.
10. 10. The laser coder according to any preceding claim, wherein the detector comprises a two-dimensional imaging sensor.
11. 11. The laser coder according to any preceding claim, wherein the controller being configured to receive the first image data comprises the controller being configured to capture, using the detector, the first image of the film substrate; wherein the controller being configured to receive the second image data comprises the controller being configured to capture, using the detector, the second image of the film substrate.
12. 12. The laser coder according to any preceding claim, wherein the marking operation is carried out in an intermittent mode or a continuous mode.
13. 13. The laser coder according to any preceding claim, the controller further configured to: output, via a display, the first image of the film substrate; receive, via a user input, a selection of an area of the first image; determine an initial address based on the selection; and set the initial address as the reference address.
14. 14. A method of operating a controller, the controller for creating marks on a film substrate with a laser beam using an address within a two-dimensional marking field, the method comprising; receiving, at the controller, first image data comprising a first image of the film substrate when the film substrate is in a first position; receiving, at the controller, second image data comprising a second image of the film substrate when the film substrate is in a second position, the film substrate having been advanced along a film substrate path in a first direction from the first position to the second position; identifying, by the controller, a difference between the first image data and second image data; generating, by the controller, an address within the two-dimensional marking field based on the identified difference and a reference address within the two-dimensional marking field; and executing, by the controller, a marking operation to mark the film substrate using the address.
15. 15. The method according to claim 14, wherein identifying the difference between the first image data and second image data comprises: identifying, by the controller, an offset between the first image and the second image, the offset indicating an offset distance in a second direction perpendicular to the first direction.
16. 16. The method according to claim 15, wherein identifying, by the controller, the offset between the first image and the second image, comprises: identifying, by the controller, a location of a first edge in the first image, the first edge parallel to the first direction; identifying, by the controller, a location of a second edge in the second image, the second edge corresponding to the first edge; identifying, by the controller, the offset based on comparing the locations of the first edge and second edge.
17. 17. The method according to claim 16, wherein identifying, by the controller, the location of the first edge in the first image, comprises: converting, by the controller, the first image into a first one-dimensional array, where each value in the first one-dimensional array represents a combination of pixel values along a first axis of the first image, the first axis parallel to the first direction; identifying, by the controller, the first edge in the first one-dimensional array; identifying, by the controller, the first location of the first edge in the first one-dimensional array.
18. 18. The method according to claim 16 or 17, wherein identifying, by the controller, the location of the second edge in the second image, comprises: converting, by the controller, the second image into a second onedimensional array, where each value in the second one-dimensional array represents a combination of pixel values along the first axis of the second image; identifying, by the controller, the second edge in the second onedimensional array; identifying, by the controller, the second location of the second edge in the second one-dimensional array.
19. 19. The method according to any of claims 15 to 18, wherein generating, by the controller, the address within the two-dimensional marking field based on the identified difference and the reference address within the two-dimensional marking field comprises: applying, by the controller, the offset to the reference address to generate the address.
20. 20. The method according to claim 19, wherein applying, by the controller, the offset to the reference address to generate the address comprises: adding the offset distance to a value of a coordinate of the reference address that specifies a position along the second direction.

Description

Laser coder and method of operation Technical Field The present disclosure relates to marking a film substrate with a laser coder. Background Film substrates are often used in the packaging industry to wrap around products (such as bottles) or to form part of, or all of, a product (such as a packet for potato chips, dried fruit or confectionary). Film substrates are typically provided to the packing industry wound on a spool or roll, and comprise individual repeating segments, where each segment may be used for an individual product. Each segment has the desired artwork for the product pre-applied, such as the manufacture’s branding, along with information about the product to which it relates (e.g. nutritional information, instructions on use, etc.). Before being used to pack a product (e.g. used in a package machine such as a Vertical Form Fill Seal (VFFS) machine), it may be necessary to mark further information onto the film substrate. This information may only be available at, or shortly before, the time of packing, such as a sell by date or lot number. Typically, such marking is done by a coder, such as a thermal transfer overprinter (TTO coder), while the film substrate is being transported along a film substrate path towards a package machine (or the like). There remains a need to provide an improved apparatus and method for marking film substrates. Summary In a first aspect, there is provided a laser coder, the laser coder comprising, a housing, a laser source disposed within the housing, the laser source configured to generate a laser beam, a laser beam steering assembly disposed within the housing, the laser beam steering assembly configured to steer the laser beam to an address within a two- dimensional marking field to create marks on a film substrate provided at a marking location adjacent to the housing, a detector configured to generate image data comprising an image of the film substrate, and a controller. The controller is configured to receive first image data comprising a first image of the film substrate when the film substrate is in a first position, receive second image data comprising a second image of the film substrate when the film substrate is in a second position, the film substrate having been advanced along a film substrate path in a first direction from the first position to the second position, identify a difference between the first image data and second image data, generate an address within the two-dimensional marking field based on the identified difference and a reference address within the two-dimensional marking field, and execute a marking operation to mark the film substrate using the address. Advantageously, the address can be updated based on a simple comparison between the first and second image data. This can be used to correct for issues such as tracking (perpendicular movement) of the film substrate. In this way, an initial address may be provided (such as the user indicating once where they desire the mark to appear on the film substrate), the initial address being the reference address, and the specific coordinates associated with the mark will automatically update over time to account for tracking. Additionally, providing a simple comparison of image data, over a more complex object/knockout detection method, allows the laser coder to accurately operate in both continuous and intermittent modes. The laser source may be an ultraviolet (UV) laser (i.e. a laser generating a laser beam comprising ultraviolet electromagnetic radiation), a near-infrared laser (i.e. a laser generating a laser beam comprising near-infrared electromagnetic radiation), or any other laser generating electromagnetic radiation suitable for marking a film substrate. Executing a marking operation to mark the film substrate using the address may comprise the controller being configured to control the UV laser source and the laser beam steering assembly to mark the film substrate using the address. The controller being configured to execute a marking operation to mark the film substrate by controlling the laser source and the laser beam steering assembly using the address may comprise the controller being configured to control the laser source to generate a laser beam and control the laser beam steering assembly to steer the laser beam according to the address. It is to be understood that reference to the first direction (e.g. the direction of advancement of the film substrate) is used to describe the normal, desired, movement of the film substrate as it is advanced past the laser coder along the film substrate path. The film substrate may, however, undergo tracking, where the film substrate shifts perpendicular to the first direction over time. The controller may be located within the housing. Alternatively, the controller may be located in a second housing different to the first mentioned housing, where the first and second housings are coupled via a suitable link (e.g. a wired or wir