METHOD AND APPARATUS FOR MANUFACTURING A DECORATED PACKAGING MATERIAL, AND A PACKAGING MATERIAL

Abstract

In some embodiments, a method for manufacturing a packaging material includes forwarding a web of said packaging material through a nip provided between an anvil roller and an imprint roller which are arranged against each other, said imprint roller having a surface area including an imprinting area and a non-imprinting area, said imprinting area comprising protrusions forming an imprinting pattern. The method can further include imprinting the imprinting pattern into an outermost layer of said packaging material with said imprinting pattern as said web passes through the nip to form a visual or tactile pattern on the packaging material corresponding to said imprinting pattern. The method can further include adjusting the position of said web when said non-imprinting area of said surface area faces said packaging material The disclosure also relates to an apparatus for manufacturing a packaging material and a packaging material.

Claims

1. A method for manufacturing a packaging material, the method comprising the steps of: forwarding a web of said packaging material through a nip provided between an anvil roller and an imprint roller, wherein the anvil roller and the imprint roller are arranged adjacent to each other, said imprint roller having a surface area including an imprinting area distributed over at least a portion of the surface area, wherein one of said imprint roller and said anvil roller has a circular cross-section and the other of said imprint roller and said anvil roller has a truncated circular cross-section, said imprinting area comprising protrusions forming an imprinting pattern; imprinting the imprinting pattern into an outermost layer of said packaging material through engagement with said imprinting pattern as said web passes through the nip to form a visual or tactile pattern on the packaging material corresponding to said imprinting pattern of said imprinting area; and adjusting a position of said web relative to the imprint roller when a truncated part of the imprint roller or of the anvil roller faces said packaging material.

2. The method according to claim 1, further comprising the step of controlling the tension of said web of packaging material in a longitudinal direction of said web with a tension control device.

3. The method according to claim 1, wherein said step of adjusting the position of said web relative the imprint roller is performed in register with a register mark on said web.

4. The method according to claim 1, wherein adjusting the position of the web relative to the imprint roller is performed by adjusting a rotational position of the imprint roller.

5. An apparatus for manufacturing a packaging material, comprising: an anvil roller and an imprint roller arranged adjacent to each other to create a nip therebetween, said imprint roller having a surface area including an imprinting area distributed at least over a portion of the surface area, said imprinting area comprising protrusions forming an imprinting pattern; a conveyor arrangement configured to forward a web of said packaging material through said nip to imprint a visual or tactile pattern on the packaging material corresponding to said imprinting pattern on the surface area of the imprint roller, wherein one of said imprint roller and said anvil roller has a circular cross-section and the other of said imprint roller and said anvil roller has a truncated circular cross-section; and a controller configured to adjust a position of said web relative to the imprint roller.

6. The apparatus according to claim 5, wherein the controller is configured to adjust a rotational position of the imprint roller when a truncated part of the imprint roller or of the anvil roller faces the packaging material.

7. The apparatus according to claim 5, wherein the controller is configured to adjust the position of the web relative to the imprint roller by adjusting the rotational position of the imprint roller.

8. The apparatus according to claim 5, further comprising a tension control device configured to control the tension of said web of packaging material in a longitudinal direction of said web of packaging material.

9. The apparatus according to claim 5, wherein the controller is configured to adjust the position of the web relative the imprint roller based on a register mark on the packaging material.

10. The apparatus according to claim 9, further comprising a sensor configured to detect said register mark.

11. The apparatus according to claim 5, wherein said imprint roller has a truncated circular cross-section, and wherein the surface area of the imprint roller further includes a non-imprinting area corresponding to a truncated portion of the truncated circular cross-section of the imprint roller.

12. The apparatus according to claim 11, wherein the non-imprinting area of said surface area comprises a softer material than the imprinting area of said surface area.

13. The apparatus according to claim 5, wherein the imprinting area of said imprint roller is releasably attached.

14. The apparatus according to claim 13, wherein said releasably attached imprinting area has a joint arranged in the non-imprinting portion of said surface area corresponding to the truncated portion of said truncated circular cross-section.

15. The packaging material, exhibiting the visual or tactile pattern, or a combination thereof, manufactured according to the method of claim 1.

16. The packaging material, exhibiting the visual or tactile pattern, or a combination thereof, in a first outermost layer of said packaging material, manufactured using the apparatus of claim 5.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The above objects, as well as additional objects, features and advantages of the present invention, will be more fully appreciated by reference to the following illustrative and non-limiting detailed description of preferred embodiments of the present invention, when taken in conjunction with the accompanying drawings, wherein:

[0025] FIG. 1 is a side view of an anvil roller and an imprint roller which are arranged against each other to create a nip therebetween in accordance with known prior art.

[0026] FIG. 2 is a side view of an apparatus for manufacturing a packaging material according to one exemplary embodiment of the invention.

[0027] FIG. 3 is a side view of the anvil roller and the imprint roller arranged against each other to create a nip therebetween in accordance with another exemplary embodiment of the invention.

[0028] FIG. 4 is a flow chart of a method for manufacturing a packaging material according to one exemplary embodiment of the invention.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS OF THE INVENTION

[0029] FIG. 1 shows a prior art solution of an apparatus 13 for manufacturing an imprinted or embossed packaging material. A web of packaging material 1 is forwarded into the nip 2 between an imprint roller 3 and an anvil roller 4. The high imprinting nip pressure and the protrusions 5 of the imprint roller 4 engaging the web of packaging material 1 makes it impossible to adjust the alignment of the web of packaging material 1.

[0030] FIG. 2 shows a first embodiment of the present invention. A web of packaging material 1 is forwarded into the nip 2 between an imprint roller 3 and an anvil roller 4. The protrusions 5 of the imprint roller 3 engages the web of packaging material 1 only when an imprinting area 6 of the imprint roller 3 is facing the web of packaging material 1 and the anvil roller 4. When the non-imprinting area 7 of the imprint roller 3 is facing the web of packaging material 1 and the anvil roller 4, the web packaging material 1 is not engaged with the rollers 3, 4 (i.e. the protrusions 5 of the imprint roller 3 are not in engagement with the web of packaging material 1) and is thereby free to be adjusted. As is seen in FIG. 2, the imprint roller 3 has the cross-section of a truncated circle, where the non-printing area 7 is constituted by the portion of the surface area of the cross-section corresponding to the truncated portion 12. For such embodiment, the anvil roller 4 is preferably provided with a flat surface area having a circular cross-section. This means that no rotational alignment is required between the anvil roller 4 and the imprint roller 3.

[0031] Still referring to FIG. 2, the non-imprinting area 7 is preferably arranged so that it is aligned with a portion of the web package material 1 that is intended for a part of the final package product where no embossing or imprinting is placed, e.g. the bottom or top parts of the package. A sensor 10 for detecting the alignment of the web of packaging material 1, in this embodiment a camera, is placed so as to detect the position of register marks 11 on the web of packaging material 1. The position of a detected register mark 11 is sent to a control unit 14 where it is compared with a database value of an expected position. If any discrepancy in the feeding direction and/or cross direction of the web of packaging material 1 is detected, the positioning of the web of packaging material 1 is adjusted accordingly by the tension control device in the form of pull and brake rollers 8, 9. The pull and break rollers 8, 9 are placed on each side of the nip 2 when the non-imprinting area 7 of the imprint roller 3 is facing the web of packaging material 1. The imprint roller 3 is further driven by a motor (not shown) that is controlled by the control unit 14.

[0032] Optionally, or in combination with the web positioning described above, the alignment of the web of packaging material 1 is determined by means of the sensor 10 and the control unit 14. Such alignment is preferably analyzed by determining the relative position of the imprinted pattern in view of the position of the register mark(s). If correction is required, e.g. if the actual position of a part of the imprinted pattern is located outside a pre-determined or desired area of the packaging material 1, the control unit 14 is configured to adjust the current rotational position of the imprint roller 3. This is possible due to the truncated circular cross-section of the imprint roller 3. When the imprint roller 3 is in a position in which the non-printing area 7 is facing the web of packaging material 1 it will be possible to rotate the imprint roller 3 slightly without risking engagement between the imprinting area 6 and the web of packaging material 1. In practice this means that when the control unit 14 determines that the location of the imprinted pattern on the web of packaging material 1 deviates from the desired position, a control signal is transmitted to the drive unit (not shown) of the imprint roller 4. Upon receiving the control signal the drive unit is configured to i) determine when the non-imprinting area 7 is facing the web of packaging material 1, and upon this ii) decelerate or accelerate the rotation of the imprint roller 3 slightly such that the subsequent imprint pattern is positioned correctly.

[0033] FIG. 3 shows an alternative embodiment of the invention. The web of packaging material 1 is forwarded into the nip 2 between an imprint roller 3 and the anvil roller 4. In this embodiment the anvil roller 4 has a flat surface and a cross-section of a truncated circle, while the imprint roller 3 has a circular cross-section. When the anvil roller 4 is positioned such that a portion of the surface area of the cross-section corresponding to the truncated portion 12 is facing the imprint roller 3, the imprint roller 3 will be disengaged from the web of packaging material 1 so that the position of the web of packaging material 1 is free to be adjusted. Alternatively, or in combination, correction of the position of the imprint pattern relative the register mark(s) is performed by adjusting the rotational position of the imprint roller 3 as described above.

[0034] FIG. 4 is a block diagram showing the inventive method of the present invention. The web of packaging material 1 is forwarded by a conveyor arrangement (not shown) through the nip 2, see FIGS. 2 and 3, provided between the anvil roller 4 and the imprint roller 3 which are arranged against each other. The imprint roller 3 has a surface area provided with an imprinting area 6 and a non-imprinting area 7 and the imprinting area 6 comprises protrusions 5 forming a imprinting pattern. Alternatively, the entire surface area of the imprint roller 3 is provided with an imprinting area 6, while the anvil roller 4 is provided with a truncated circular cross-section as described with reference to FIG. 3.

[0035] The of web of packaging material 1 is provided with an embossed pattern when the imprint roller 3 is engaging the web of package material 1 against the anvil roller 4 so as to imprint a visual and/or tactile pattern on the packaging material corresponding to the imprinting pattern of the imprinting area. In the case of a laminated packaging material, the embossed pattern may be made in the outermost or outer layers only. The tension of the web is controlled by a tension control device consisting of pull and brake rollers 8, 9. When the truncated parts of the imprint roller 3 in FIG. 2, or alternatively of the anvil roller 4 in FIG. 3, are facing the web of packaging material 1, there will be no engagement between the imprint roller 3 and the web of packaging material 1, such that a step of adjusting the position of the web can be performed if any discrepancy of the position of the web has been detected. The adjustment is especially made in a longitudinal direction of the web by means of the tension control device 8, 9 in relation to any discrepancy detected by the sensor 10, and/or by correcting the rotational position of the imprint roller 3. The discrepancy is determined by the control unit 14 by comparing the position of register marks 11 on the packaging material 1 detected by the sensor 10 and values stored in a database. In that way, detection and adjustment of the position of the web of packaging material 1 may be fully automated.

[0036] The skilled person realizes that a number of modifications of the embodiments described herein are possible without departing from the scope of the invention, which is defined in the appended claims.