Packaging machine and method for producing packages from packaging material

Abstract

A packaging machine and method for producing sealed packages from a packaging material fed along a transport path (P) and having at least two reference marks (14, 15; 14 *, 15 *), said packaging machine comprising a control device (8) having a plurality of reference marking patterns (12) configured to measure at least a first parameter (D1; v) configured for measuring at least a second parameter (D2; V) of the packaging material when the packaging material has a substantially tubular shape; d4), and a control unit (16) connected to both the sensing device (17) and the imaging device (11) and configured to control the sensing device (17) and the imaging device (11) based on the first parameter (D1; v) and the second parameter (D2; the width of the overlapping region (AO) of the tubes (5) is calculated.

Description

Technical Field

[0001] The present invention relates to a packaging machine and a packaging method for producing packages from packaging material. In particular, the present invention relates to a packaging machine comprising a control device for detecting parameters of a tube formed by folding packaging material and filled with a product to be packaged. In particular, the present invention also relates to a packaging method comprising the step of detecting parameters of a tube formed by folding packaging material and filled with a product to be packaged. Background Art

[0002] It is known that many liquid or pourable food products, such as pasteurized milk or ultra-high temperature (UHT) milk, ketchup, wine, fruit juice are sold in packages made of sterilized packaging material.

[0003] Such packages are usually produced by automatic packaging machines which feed the packaging material web through a sterilization unit by means of known guiding elements, such as rollers, and alternatively sterilize the packaging material web by chemical sterilization in a sterilization bath (e.g. by applying a chemical sterilizing agent, such as a hydrogen peroxide solution) or by physical sterilization (e.g. by means of an electron beam).

[0004] The packaging machine further comprises a folding unit, which is arranged downstream of the sterilization unit and is arranged to fold the packaging material web to produce a continuous tube. Inside the folding unit, the packaging material web is folded from a continuous planar shape into a continuous tubular shape with a vertical axis. The planar packaging material web is folded into a cylinder, which is in turn divided into a plurality of pillow-shaped packages, which are subjected to a continuous mechanical folding operation to obtain a finished sealed package. The folding unit is preferably arranged in a fixed structure, wherein the packaging material web is maintained in a sterile air environment. The folding unit further comprises a plurality of folding devices placed in series (one after another): by interaction with the folding devices, the opposite side edge portions (or edge regions) of the packaging material web are superimposed one on top of the other so as to form a tube and define an overlapping area.

[0005] The packaging machine comprises a sealing unit, which is arranged downstream of the folding unit, for sealing overlapping edge portions of the web of packaging material to obtain a liquid-tight longitudinal seal within the tube.

[0006] The pourable food product is continuously filled into the tube via a pouring conduit which extends partly into the interior of the tube and is part of the filling route.

[0007] The tube is finally sent to the forming and transverse sealing unit where it is clamped, transversely sealed and cut to form pillow packs.

[0008] In the above-mentioned packaging machines, in order to ensure good quality of the transverse sealing of the packaging material tube, the tube has to be fed in such a way that the overlapping area has a predetermined angular position with respect to the vertical axis and that said overlapping area has a predetermined width.

[0009] Typically, the width of the overlap area is simply measured manually by an operator on a few randomly sampled sealed packages.

[0010] Therefore, there is a strong need for a reliable automatic measurement of overlap region width. Summary of the invention

[0011] The object of the present invention is to provide a packaging machine for producing packages from packaging material which does not suffer from the above-mentioned disadvantages and which is in particular easy and economical to manufacture.

[0012] Another object of the invention is to provide a packaging method for producing a package from a packaging material which does not suffer from the above-mentioned disadvantages and which is particularly easy and economical to implement.

[0013] According to the present invention, there are provided a packaging machine and a packaging method for producing packages from packaging material according to the accompanying claims. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Non-limiting embodiments of the present invention will be described by way of example with reference to the accompanying drawings, in which:

[0015] - Figure 1 is a perspective view of a packaging machine for producing packages from packaging material according to the invention, with some parts removed for the sake of clarity;

[0016] - Figure 2 yes Figure 1 A schematic side view of a first part of a packaging machine;

[0017] - Figure 3 yes Figure 1 A perspective view of a second portion of the packaging machine;

[0018] - Figure 4 Shows the use of Figure 1 A first embodiment of a packaging machine for obtaining a planar portion of a packaged packaging material;

[0019] - Figure 5 Shows Figure 4 A partial view of a tube obtained by folding a portion of the packaging material in the tube;

[0020] - Figure 6 Shows the use of Figure 1 A second embodiment of a packaging machine for obtaining a planar portion of a packaged packaging material; and

[0021] - Figure 7Shows Figure 6 A partial view of a tube obtained by folding a portion of the packaging material in FIG. DETAILED DESCRIPTION

[0022] Figure 1 and Figure 2 The present invention generally shows a packaging machine 1 for continuously producing sealed packages containing pourable food products, such as pasteurized milk or extended shelf life (UHT) milk, ketchup, wine, fruit juice. The sealed packages are obtained from packaging material unwound from a reel 21 and fed along a conveying path P. When unwound from the reel 21, the packaging material has the shape of a continuous flat packaging material web 20.

[0023] Typically, the packaging material has a multilayer structure. More specifically, the packaging material may include at least one fibrous material layer, such as a paper or cardboard layer, and at least two heat-sealing plastic material layers, such as polyethylene, between which the fibrous material layers are placed. One of the two heat-sealing plastic material layers may define an inner face of the package that eventually contacts the pourable product.

[0024] According to some possible non-limiting embodiments, the packaging material may further comprise a layer of gas barrier and light barrier material, such as an aluminum foil or an ethylene vinyl alcohol (EVOH) film, in particular arranged between one of the heat-sealable plastic material layers and the fiber material layer. Preferably, the packaging material may further comprise another layer of heat-sealable plastic material placed between the gas barrier and light barrier material layer and the fiber material layer.

[0025] The packaging machine 1 comprises a sterilization unit 3 with a sterilization bath 19, in which a chemical sterilant, such as a hydrogen peroxide solution, is applied to a packaging material web 20. The packaging material web 20 is fed through the sterilization unit 3 by known guide elements, such as rollers or the like.

[0026] The packaging machine 1 further comprises a folding unit 4 arranged downstream of the sterilization unit 3 along the conveying path P. The folding unit 4 preferably extends substantially vertically along the conveying path P for producing a continuous tube 5. In particular, inside the folding unit 4, the packaging material web 20 is folded from a continuous planar shape into a continuous tubular shape having a longitudinal axis Y. In particular, the longitudinal axis Y is arranged in the vertical direction.

[0027] The folding unit 4 is defined within a fixed structure 6, wherein the packaging material web 20 is maintained in a sterile air environment. The folding unit 4 also includes a plurality of folding devices 100 placed in series (one after another) along the conveying path P, each of the folding devices 100 including a plurality of folding rollers cooperating to fold the packaging material web 20.

[0028] The packaging machine 1 comprises a sealing unit 7 (of a known type, not described in detail) for sealing the overlapping side edges 13A, 13B of the packaging material so as to obtain a liquid-tight longitudinal seal inside the tube 5 .

[0029] The tube 5 is continuously filled with the pourable food product via a pouring duct 101 which extends partly inside the tube 5 and is part of the filling route.

[0030] The tube 5 is sent to a forming and transverse sealing unit (not shown) where the tube 5 is clamped to transversely seal the tube and form the pillow pack 2. Finally, the pillow pack 2 is subjected to a continuous mechanical folding operation to obtain a finished sealed package.

[0031] The packaging machine 1 comprises a control device 8, which is configured to measure and control the angular position T of the edge 13B relative to the longitudinal axis Y (i.e. the rotation or twisting of the tube 5 around the longitudinal axis Y) and / or the width of the overlapping area AO defined by the overlapping parts of the packaging material edge 13A and the packaging material edge 13B.

[0032] The packaging material web 20 comprises a plurality of reference marking patterns 12 arranged one behind the other along the longitudinal dimension of the packaging material web 20 (and the tube 5) to provide information about the position of the packaging material.

[0033] Each reference marking pattern 12 defines, or is part of, a unit of packaging material 13 for forming a respective sealed package.

[0034] Figure 4 A first embodiment of a reference mark pattern is shown. The reference mark pattern 12 comprises at least two reference marks 14, 15. In the embodiment shown, the reference marks 14, 15 are dedicated marks, having a generally square shape. Alternatively, the reference marks 14, 15 may be already existing marks (e.g. a splicing mark or a barcode or the like).

[0035] The reference mark 14 is arranged near the edge 13A of the packaging material. The reference mark 14 has a reference area 14A, for example an edge area facing the edge 13A.

[0036] A distance D1 is defined between the edge 13A of the packaging material and the reference area 14A. The distance D1 is not zero.

[0037] The reference mark 15 is arranged in the vicinity of the packaging material edge 13B. In particular, the reference mark 15 has a reference area 15B, preferably corresponding to the packaging material edge 13B.

[0038] The second edge 13A may include a portion of the packaging material between a boundary of the second edge 13A and the reference mark 14 .

[0039] The first edge 13B of the packaging material may be placed at least partially on top of the second edge 13A, ie the (outer) border of the edge 13B of the packaging material may be placed on top of the second edge 13A.

[0040] The control device 8 comprises a sensor device 17 having at least one sensor 18. According to a first embodiment, the sensor 18 is adapted to frame a longitudinal portion of a packaging material web 20. Preferably, the longitudinal portion of the packaging material web 20 framed by the sensor 18 comprises a packaging material unit 13. Even more preferably, the longitudinal portion of the packaging material web 20 framed by the sensor 18 corresponds to the packaging material unit 13. In one embodiment, the sensor 18 is preferably a camera 18A.

[0041] The sensing device 17 is configured to measure the distance D1 of each packaging material unit 13 when the packaging material has a planar shape. The sensing device 17 is arranged along the conveying path P. Preferably, the sensing device 17 is arranged upstream of the sterilization unit 3 .

[0042] The control device 8 also includes Figure 3 The control device 8 preferably further comprises a fixed frame having a movable bracket (not shown) supporting the imaging device 9. The movable bracket can rotate about an axis between a working position and a rest position, in which the imaging device 9 faces the tube 5 and is arranged near the tube 5, and in which the imaging device 9 does not face the tube 5 and is arranged at a distance from the tube 5.

[0043] The imaging device 9 comprises at least one sensor 11, which is adapted to frame at least a longitudinal portion of the tube 5. The sensor 11 is preferably a camera 11A. The imaging device 9 is arranged downstream of the sealing unit 7. In particular, the sensor 11, i.e. the camera 11A, is adapted to frame a longitudinal portion of the tube 5. Preferably, the longitudinal portion of the tube 5 framed by the sensor 11 comprises a packaging material unit 13. Even more preferably, the longitudinal portion of the packaging material web 20 framed by the sensor 18 corresponds to the packaging material unit 13.

[0044] When the packaging material web 20 is folded from a flat shape into a (e.g., substantially) tubular shape, the packaging material edge 13B at least partially overlaps the packaging material edge 13A, thereby defining an overlapping area AO formed by the overlapping sides of the packaging material. During the preliminary setup and design phase of the working cycle of the packaging machine 1, a reference value for the width of the overlapping area AO is defined. In other words, the reference value is a preferred value or an optimal value corresponding to the correct working state of the packaging machine 1. It is worth noting that the distance D1 (when the mark 14 is printed on the packaging material) must be selected so that it is greater than the reference value. In addition, a distance D2 is defined between the reference area 15B (which corresponds to the packaging material edge 13B in the illustrated embodiment) and the reference area 14A. When the packaging material web 20 has a (e.g., substantially) tubular shape, the distance D2 is measured, as Figure 5 The distance D2 is measured by the imaging device 9 , in particular for each packaging material unit 13 .

[0045] Finally, the control device 8 comprises a control unit 16, which is connected to both the imaging device 9 and the sensor device 17. In particular, the imaging device 9 is designed to generate a signal indicating the distance D2 of each unit of packaging material 13 and transmit it to the control unit 16. The sensor device 17 is designed to generate a signal indicating the distance D1 of each unit of packaging material 13 and transmit it to the control unit 16. The control unit 16 calculates the actual value of the overlapping area AO from the difference between the distance D1 and the distance D2 of each unit of packaging material 13.

[0046] The control unit 16 also compares the actual value of the overlap area AO with a reference value. In case the difference between the actual value and the reference value of the overlap area AO exceeds a predetermined threshold, the control unit 16 is designed to generate a warning signal for informing of an undesirable significant deviation from the reference value.

[0047] According to a preferred embodiment, the control unit 16 is realized to control the folding unit 4 and the sealing unit 7 based on the actual value of the overlap area AO.

[0048] According to another embodiment not shown, the reference mark pattern 12 includes the reference mark 14 as described above, and the reference mark 15 is at the packaging material edge 13B. In other words, the reference mark pattern 12 does not include a dedicated reference mark 15, but the reference mark 15 is defined by the packaging material edge 13B. The distance D2 measured by the imaging device 9 is defined between the packaging material edge 13B and the reference area 14A.

[0049] Figure 6 and Figure 7 A second embodiment of a reference mark pattern 12 is shown.

[0050] The reference mark pattern 12 comprises at least two reference marks 14*, 15*. In the embodiment shown, the reference marks 14*, 15* are already existing marks (such as splicing marks or bar codes or the like). Alternatively, the reference marks 14*, 15* can be dedicated marks.

[0051] The reference mark 14* is arranged near the packaging material edge 13A and the reference mark 15* is arranged near the packaging material edge 13B.

[0052] The first edge 13B may comprise a portion of the packaging material between a border of the first edge 13B and the reference mark 15*. The second edge 13A may comprise a portion of the packaging material between a border of the second edge 13A and the reference mark 14*.

[0053] For example, the (outer) border of edge 13B of the packaging material may be placed on top of the second edge 13A.

[0054] according to Figure 6 and Figure 7 In the embodiment shown in FIG. 1 , the sensor 18 is a camera 18A or alternatively a through-beam sensor 18 , preferably a through-beam laser sensor 18 .

[0055] The sensing device 17 is configured to measure a width V of each packaging material unit 13, ie a width from a packaging material edge 13A to a packaging material edge 13B of the packaging material web 20, when the packaging material has a planar shape.

[0056] Furthermore, the manufacturer of the packaging material web 20 provides information about the packaging material, such as the distance D3 between the reference markings 14*, 15*. In more detail, the manufacturer of the packaging material web 20 provides the distance D3 defined between the reference point 14A* of the reference marking 14* and the reference point 15A* of the reference marking 15* (in particular the edge). Therefore, the distance D3 has a predefined value stored in the control unit 16.

[0057] The imaging device 9 is configured to measure a distance D4 between the reference mark 14* and the reference mark 15*, for example when the packaging material is folded into a (e.g. substantially) tubular shape. In more detail, the distance D4 is defined between a reference point 15A* of the reference mark 15* and a reference point 14A* of the reference mark 14* of the tube 5.

[0058] The imaging device 9 is designed to generate a signal indicating the distance D4 of each packaging material unit 13 and transmit it to the control unit 16. Then, the control unit 16 calculates the total perimeter of each packaging material unit 13 by adding the distance D3 to the distance D4. Finally, the control unit 16 calculates the actual value of the overlapping area AO by the difference between the width V obtained as described above and the total perimeter of each packaging material unit 13.

[0059] In this case, too, if the difference between the actual value of the overlap area AO and the reference value exceeds a predetermined threshold, the control unit 16 is designed to generate a warning signal for informing that there is an undesirable significant deviation from the reference value. According to a preferred embodiment, the control unit 16 is implemented to use the actual value of the overlap area AO for closed-loop control of the folding unit 4 and / or the sealing unit 7.

[0060] The image of each packaging material unit 13 provided by the imaging device 9 is used to measure the angular position T of the formed packaging material edge 13B relative to the longitudinal axis Y, which is representative of the rotation or twisting of the tube 5 about the longitudinal axis Y.

[0061] According to a first embodiment, the camera 11A is suitable for continuously acquiring images of at least a longitudinal portion of the tube 5 and of a reference mark (not shown). In particular, the camera 11A is suitable for framing the longitudinal portion of the tube 5 and the reference mark. The reference mark is connected to the frame of the packaging machine 1 and is therefore arranged in a fixed position relative to the tube 5 advancing along the advancement path P. According to a possible embodiment, the reference mark is defined by a slit in a bracket connected to the frame of the packaging machine 1.

[0062] For each image acquired by the camera 11A, the control unit 16 is configured to measure, based on the position of the packaging material edge 13B relative to the reference mark, an angular position T of the packaging material edge 13B relative to the longitudinal axis Y. In particular, the control unit 16 is configured to measure the angular position T of the packaging material edge 13B relative to the longitudinal axis Y based on the distance of the packaging material edge 13B from the reference mark.

[0063] In one or more embodiments, the control unit 16 is configured to measure the angular position T of the wrapper edge 13B relative to the longitudinal axis Y based on the position of the (outer) boundary of said wrapper edge 13B relative to the reference mark.

[0064] According to a further preferred embodiment, the camera 11A is adapted to acquire a reference image during a preliminary setup phase. The reference image comprises at least a longitudinal portion of the tube 5 and a removable reference marker. The reference marker is connected to the frame of the packaging machine 1. According to a possible embodiment, the reference marker is defined by a slit in a bracket that is detachably connected to the frame of the packaging machine 1. After acquiring the reference image during the preliminary setup phase, the removable reference marker is removed from the packaging machine 1 and the reference image is stored in the control unit 16.

[0065] The control unit 16 is configured to compare the image provided by the imaging device 9 with a reference image. In particular, the control unit 16 is configured to measure the angular position T of the packaging material edge 13B relative to the longitudinal axis Y based on a displacement of the packaging material edge 13B relative to a reference position of the packaging material edge 13B in the reference image.

[0066] In both embodiments, the assessment of the correct positioning of the packaging material edge 13B allows the user to determine whether the formed tube 5 is arranged in the correct position relative to the longitudinal axis Y. According to a preferred embodiment, the control unit 16 is indeed implemented to control the folding unit 4 and the sealing unit 7 based on the angular position T of the packaging material edge 13B.

[0067] In case the angular position T of the formed packaging material edge 13B relative to the longitudinal axis Y is greater than a predetermined threshold value, the control unit 16 is designed to generate a warning signal for informing of an undesired significant deviation.

[0068] According to a preferred embodiment, the control unit 16 is configured to use the angular position T of the packaging material edge 13B for closed-loop control of the folding unit 4 and / or the sealing unit 7 .

[0069] Obviously, using the same image provided by the camera 11A for each unit 13 of packaging material, the control device 8 can measure and control both the actual value of the overlap area AO and the twisting of the tube 5 about the longitudinal axis Y.

[0070] Reference numerals list 1Packing Machine 2 packs 3Sterilization units 4 Folding units 5 tubes 6 Structure 7 Sealing unit 8 Control device 9 Imaging equipment 11 Sensors 12 Reference Mark Pattern 13 Packaging material unit 14. 14*Reference mark 14A* reference point 15, 15*Reference mark 15A*reference point 16Control Unit 17Sensor equipment 18 Sensors 19 Sterilization bath 20 Packaging material rolls 21 Reels P transmission path Y longitudinal axis D1 distance D2 distance AO overlap area V Width D3 distance D4 distance T Angular position of packaging material edge 13B

Claims

1. A packaging machine for producing sealed packages from packaging material, the packaging material being fed along a conveying path (P), the packaging material having a plurality of reference mark patterns (12), the patterns (12) being arranged one behind the other along a longitudinal dimension of the packaging material; each of the patterns (12) defining a packaging material unit (13) for a respective sealed package and comprising at least two reference marks (14, 15; 14*, 15*); the packaging machine (1) comprising a folding unit (4), arranged along the conveying path (P), for folding the packaging material from a flat surface into a tube (5) having a longitudinal axis (Y), wherein a first edge (13B) of the packaging material is at least partially placed on top of a second edge (13A) of the packaging material, thereby defining an overlapping area (AO) of the packaging material; and a control device (8), comprising: a sensing device (17) having at least a first sensor (18) arranged upstream of the folding unit (4) along the conveying path (P); the sensing device (17) being configured to measure at least a first parameter (D1; V) of the packaging material when the packaging material has a planar shape and to generate a first signal indicative of the first parameter (D1; V); an imaging device (9) having at least a second sensor (11) arranged along the conveying path (P) downstream of the folding unit (4) and adapted to frame at least a longitudinal portion of the tube (5); the imaging device (11) being configured to measure at least a second parameter (D2; D4) of the packaging material and to generate a second signal indicative of the second parameter (D2; D4); as well as A control unit (16) is connected to both the sensing device (17) and the imaging device (11) and is configured to calculate a width of the overlapping area (AO) based on the first signal and the second signal.

2. A packaging machine according to claim 1, and further comprising a sealing unit (7), which is arranged downstream of the folding unit (4) along the conveying path (P) to obtain a liquid-tight longitudinal seal in the tube (5), and the imaging device (9) is placed downstream of the sealing unit (7).

3. A packaging machine according to claim 1 or 2, and comprising a sterilization unit (3) for the packaging material arranged upstream of the folding unit (4) along the conveying path (P), the sensor device (17) being placed upstream of the sterilization unit (3).

4. The packaging machine according to any of the preceding claims, wherein the first sensor (18) is a first camera (18A) or a through-beam sensor (18), preferably a through-beam laser sensor (18).

5. Packaging machine according to any of the preceding claims, wherein the second sensor (11) is a second camera (11A).

6. A method for producing sealed packages from a packaging material, the packaging material being fed along a conveying path (P), the packaging material having a plurality of reference marking patterns (12), the patterns (12) being arranged one behind the other along the longitudinal dimension of the packaging material; each of the patterns (12) defining a packaging material unit (13) for a respective sealed package and comprising at least two reference markings (14, 15; 14*, 15*); the method comprising the following steps: - when the packaging material has a planar shape, acquiring an image of a longitudinal portion of the packaging material for measuring at least a first parameter (D1; V) of the packaging material unit (13); - folding the packaging material from a flat surface into a tube (5) having a longitudinal axis (Y) such that a first edge (13B) of the packaging material at least partially overlaps a second edge (13A) of the packaging material, thereby defining an overlapping area (AO) of the packaging material; - acquiring an image of at least a longitudinal portion of the tube (5) for measuring at least a second parameter (D2; D4) of the unit of packaging material (13); and - calculating the width of said overlapping area (AO) based on said first parameter (D1; V) and said second parameter (D2; D4).

7. The packaging method according to claim 6, wherein a first reference mark (14) is arranged near the second edge (13A) of the packaging material; and wherein the first parameter (D1) is the distance between the second edge (13A) of the packaging material and the first reference mark (14).

8. A packaging method according to claim 7, wherein the second parameter (D2) is the distance between the second reference mark (15) and the first reference mark (14); and wherein the method comprises a further step of calculating the width of the overlapping area (AO) by the difference between the first parameter (D1) and the second parameter (D2).

9. Packaging method according to claim 8, wherein the second reference mark (15) is at the first edge (13B), preferably at the border of the first edge (13B) of the packaging material.

10. The packaging method according to claim 8, wherein the second reference mark (15) has a reference portion (15B) corresponding to the first edge (13B) of the packaging material, and wherein the second parameter (D2) is a distance between the reference portion (15B) of the second reference mark (15) and the reference portion (14A) of the first reference mark (14).

11. Packaging method according to claim 10, wherein the reference portion (14A) is an edge of the first reference mark (14) facing the second edge (13A) of the packaging material.

12. The packaging method according to claim 6, wherein a first reference mark (14*) is arranged near the second edge (13A) of the packaging material, and a second reference mark (15*) is arranged near the first edge (13B) of the packaging material; and wherein when the packaging material has a planar shape, the first parameter (V) is the width of the packaging material from the first edge (13B) to the second edge (13A).

13. A packaging method according to claim 12, wherein the second parameter (D4) is the distance between the first reference mark (14*) and the second reference mark (15*) when the packaging material is folded; and wherein the method comprises the following further steps: - obtaining a third parameter (D3) indicating the distance between said first reference mark (14*) and said second reference mark (15*); - calculating the circumference of the tube (5) by the sum of the third parameter (D3) and the second parameter (D4); and - calculating the width of the overlapping area (AO) by the difference between the first parameter (V) and the perimeter.

14. A packaging method according to any one of claims 6 to 12, wherein when the difference between the width of the overlapping area (AO) and a reference value exceeds a preset threshold, the method includes another step of generating a warning signal and / or another step of performing closed-loop control of the folding step.

15. Packaging method according to any one of claims 6 to 14, and comprising the further step of using the image of at least a longitudinal portion of the tube (5) to measure the angular position (T) of the first edge (13B), preferably its border, relative to the longitudinal axis (Y).

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