METHOD AND DEVICE FOR PROCESSING A COVER OF A PACKAGE

Abstract

The present invention relates to a method for processing a covering roll sheet (20) of a package, wherein the covering roll sheet (20) covers a package body (51) in the manner of a lid, comprising the steps of: drawing the covering roll sheet (20) off an endless roll (22), tensioning the covering roll sheet (20), determining an offset between a first marking on the covering roll sheet (20) and a second marking (34) on the package body (51), and stretching the covering roll sheet (20) in a manner dependent on the determined offset between the first marking (33) and the second marking (34).

Claims

1. A method for processing a cover web (20) of a package, wherein the cover web (20) covers a packaging body (51) in the manner of a lid, comprising the steps: unreeling the cover web (20) from an endless reel (22), tensioning the cover web (20), determining a misalignment between a first mark on the cover web (20) and a second mark (34) on the packaging body (51), and stretching the cover web (20) depending on the determined misalignment between the first mark (33) and the second mark (34).

2. The method as claimed in claim 1, wherein the cover web (20) is guided over a dancer roll arrangement (21) after being unreeled from the endless reel (22).

3. The method as claimed in claim 1, wherein the stretching step takes place in just one direction.

4. The method as claimed in claim 3, wherein the stretching step takes place just in a transporting direction (6).

5. The method as claimed in claim 1, wherein the cover web (20) comprises a composite material comprising paper material and at least one surface coating.

6. The method as claimed in claim 1, wherein the stretching step is carried out on a section of the cover web (20) which is determined by clamping the cover web at at least two side regions, and the stretching step is then performed at the clamped section by an elongated expanding device (41).

7. The method as claimed in claim 6, wherein the elongated expanding device (41) is arranged transversely to a transporting direction (6) of the cover web.

8. The method as claimed in claim 6, wherein a travel (W) of the elongated expanding device (41) perpendicular to a surface of the cover web (20) is selected depending on the determined misalignment between the first and second mark (33, 34).

9. The method as claimed in claim 1, further comprising the step of fixing the stretched cover web (20) on the packaging body (51).

10. A device for processing a cover web (20) of a package (5), wherein the cover web (20) is configured to cover a packaging body (51) in the manner of a lid, comprising: an unreeling device (2) for unreeling the cover web (20) from an endless reel (22), a first detection sensor (31) for detecting a first mark (33) on the cover web (20) and a second detection sensor (32) for detecting a second mark (34) on the packaging body (51) or a packaging body web, a stretching device (4) which is configured to perform a stretching process on the cover web (20), and a control unit (7) which is configured to perform the stretching process based on a detected misalignment between the first mark (33) and the second mark (34).

11. The device as claimed in claim 10, wherein the control unit (7) is configured to determine, based on the detected misalignment between the first and second mark (33, 34), a traveling distance (W) by which an elongated expanding device (41) of the stretching device (4) needs to move perpendicular to a surface of the cover web (20) for the stretching process.

12. The device as claimed in claim 10, wherein the elongated expanding device (41) of the stretching device (4) is arranged transversely to a transporting direction (6) of the cover web (20).

13. The device as claimed in claim 10, further comprising a clamping device (42) which has a plurality of clamping jaws (43) and is configured to clamp during the stretching process a section of the cover web (20) which is to be stretched.

14. The device as claimed in claim 10, further comprising a dancer roll arrangement (21) between the unreeling device (2) and the stretching device (4).

15. A packaging machine comprising a device as claimed in claim 10.

Description

SHORT DESCRIPTION OF THE DRAWINGS

[0019] A preferred exemplary embodiment of the invention is described in detail below with reference to the attached drawings, in which:

[0020] FIG. 1 shows a schematic view of a device for processing a cover web in an overall view with a packaging machine according to the present invention,

[0021] FIG. 2 shows a schematic side view of a stretching device from FIG. 1, and

[0022] FIG. 3 shows a schematic plan view of the stretching device from FIG. 2.

PREFERRED EMBODIMENT OF THE INVENTION

[0023] A device 1 for processing a cover web 20 and an associated processing method for the cover web 20 is described below in detail with reference to FIGS. 1 to 3.

[0024] As can be seen from FIG. 1, the device 1 for processing the cover web is part of a packaging machine 100 for producing and filling a package 5. The package 5 comprises a packaging body 51 and a lid 52. The packaging body 51 has a cavity 53 for receiving a product to be packaged, for example a foodstuff, and the lid 52 covers the package 5.

[0025] The packaging machine 100 also comprises, in addition to the device 1 for processing the cover web 20, a machine part 10 for producing the packaging body 51. The machine part 10 here comprises an endless reel 11 with an unreeling device and a dancer roll arrangement 12 and a shaping unit 13 which introduces a depression 15, which defines the cavity 53 of the package, into the endless web 14 of the packaging body. A product which is to be packaged is placed into the depression 15, as indicated schematically by the arrow 16 in FIG. 1. The filled depression 15 is then sealed by a cover web, as explained in detail below.

[0026] The device 1 for processing the cover web 20 here comprises an unreeling device 2 which unreels the cover web from an endless reel 22. The unreeling here takes place continuously. The unreeling device 2 moreover comprises a dancer roll arrangement 21 with three rolls 21a, 21b, 21c. The dancer roll arrangement 21 thus enables the cover web 20 to be able to be unreeled continuously from the reel 22 and the cover web 20 nevertheless to be processed in a stretching device 4 when stationary.

[0027] The stretching device 4 is likewise part of the device 1 for processing the cover web 20 and is shown in detail in FIGS. 2 and 3. The stretching device 4 here comprises an elongated expanding device 41 in the form of an elongated bar. The cover web 20 here has a first width B1 which is smaller than a second width B2 of the elongated expanding device 41.

[0028] As shown in FIG. 3, the elongated expanding device 41 is here arranged transversely to a transporting direction 6 of the cover web 20.

[0029] The stretching device 4 moreover comprises a clamping device 42 which can clamp the cover web 20 at both free sides. For this purpose, the clamping device 42 has four clamping jaws 43.

[0030] The stretching device 4 moreover comprises a fluid drive 44 which moves the elongated expanding device 41 downward in the direction of the arrow A. As can be seen in FIG. 2, the elongated expanding device 41 is here arranged in the section between the clamping jaws 43 which clamp the cover web 20.

[0031] The device 1 for processing the cover web 20 moreover comprises a sensor device with a first detection sensor 31 and a second detection sensor 32. The first detection sensor 31 here detects a first mark 33 which is provided on the cover web 20. The second detection sensor 32 detects a second mark 34 which is arranged on the web 14 for the packaging body 51. A corresponding mark is hereby provided on each of the webs per packaging body 51 and per lid 52. The second mark 34 is indicated schematically in FIG. 1.

[0032] The device 1 furthermore comprises a control unit 7 which is connected to the first detection sensor 31 and the second detection sensor 32. The control unit 7 is moreover also connected to the stretching device 4 and controls the latter.

[0033] The detected positions of the marks 33, 34 which are detected by means of the first and second detection sensor 31, 32 are fed to the control unit 7. The control unit 7 then carries out a target/actual comparison with saved target positions for the marks and thus determines a possible misalignment between the first and second mark 33, 34.

[0034] The control unit 7 is thus configured to actuate the stretching device 4 based on this possible misalignment. A traveling distance W is hereby determined, based on the detected misalignment, by which the elongated expanding device 4 is moved in the direction of the arrow A in order to enable that section of the cover web 20 which is clamped between the clamping jaws 43 to be stretched or expanded. The traveling distance W and also, in dashed lines, the position of the cover web 20′ and of the elongated expanding device 41′ are indicated in FIG. 2.

[0035] The method according to the invention for processing the cover web 20 to provide a cover 52 for the packaging body 51 thus includes the steps of unreeling the cover web 20 from the endless reel 22 and tensioning the cover web 20 by clamping the cover web 20 between the clamping jaws 43. A possible misalignment between the first mark 33 on the cover web 20 and the second mark 34 on the web 14 for the packaging body 51 has preferably also been determined at the same time and fed to the control unit 7. A step of stretching the cover web 20 then takes place in the clamped state depending on the determined misalignment between the first and the second mark 33, 34.

[0036] The stretching step here takes place in the clamped state of the cover web 20, i.e. this region of the web is stationary. So that the cover web 20 can continue to be unreeled continuously from the endless reel 22, the dancer roll arrangement 21 is provided which makes it possible, when the cover web 20 is stationary during the stretching step, to adjust the endless reel 22 which continues to be unreeled continuously. At least one of the rolls of the dancer roll arrangement 21 is here moved perpendicular to its axis of rotation.

[0037] Owing to the stretching of the cover web 20, faulty alignment between the two marks can thus be avoided in a subsequent step in which the package is joined together. The cover web 20 and the web 14 for the packaging body 51 are thus fed in a synchronized fashion to a sealing station 17. The two webs are then sealed together in the sealing station 17. The sealed package is then die-cut in a separating station 18 and the package 5 produced in this way is transported away (arrow 19).

[0038] The device 1 according to the invention and the method according to the invention are here particularly suitable when paper material is used for the package. Paper material can hereby be used exclusively for both the lower part and the lid of the package. Alternatively, a composite material comprising a paper material and a plastic coating can in particular be used for the lid of the package. As a result, the stretching step can be performed particularly efficiently and in particular the subsequent sealing step can also be performed without any problems.

[0039] Position deviations, which can occur for example owing to the use of paper materials for the package, can be in particular be compensated owing to the synchronization. Because the packages are usually printed, variations in the printed image can thus in particular be compensated. As a result, the package 5 which is produced has a visually attractive appearance. Furthermore, a length of the cover web 20 which is aligned for the lid can also be varied by the stretching step. Length adjustment can hereby likewise be determined by determining the misalignment between the first and second mark 33, 34.

[0040] It should be noted that the stretching step usually forms plastic deformation of the covering web. It should be noted hereby that the covering web can also have a coating on both the top and the underside which later faces the product.