Arrangement and method for ejecting misaligned carton sheets from a conveyor, and corresponding computer program product

Abstract

An ejection arrangement (1) for removing misaligned carton sheets (2) from a conveyor (10) transporting sheets in a specified direction (D). The arrangement includes an ejection opening (11) positioned below the conveying surface and comprises a sensor (30) that generates signals (S1) indicating the presence of carton sheets (2). An air expulsion unit (40), mounted above the ejection opening (11), is configured to direct air bursts (42) onto the sheets. A control unit (50) receives signals (S1), determines sheet misalignment by analyzing rotation or overlap, and activates the air expulsion unit (40) to divert misaligned sheets (2d, 2e) into the ejection opening (11). This arrangement efficiently removes misaligned sheets to ensure smooth conveyor operations.

Description

Technical Field

[0001] The invention relates in general to conveyors for carton sheets. In particular, the invention relates to an ejection arrangement for ejecting misaligned carton sheets being transported in a transportation direction along a conveyor. Additionally, the invention relates to a method in a control unit of an ejection arrangement for ejecting misaligned carton sheets being transported in a transportation direction along a conveyor. The invention further relates to a computer program product performing the method.Background Art

[0002] In today's production lines for carton packaging used in various types of goods or consumer products, carton packages are typically produced as flat carton sheets, which are later folded into their final shape and form. One conventional method of producing flat carton sheets starts with printing on large rolls of carton material. The printed carton material may then be laminated, after which the rolls are slit into reels and subsequently creased and cut into individual carton sheets, also commonly referred to as blanks. The carton sheets may then be fed individually onto a conveyor or conveyor belt, which conveys the sheets at high speed through a process known as side-sealing.

[0003] During side-sealing, individual cartons may undergo various operations at different stations before reaching the end of the production line, ready for folding. These operations may involve the application of adhesive tapes, glues, staples, and other materials to customize the cartons to safely carry various types of goods and consumer products, including food, medicine, beverages, chemicals, household appliances, textiles, electronics, and more.

[0004] Fig. 1 shows a perspective side view of a conveyor 100 that may be suitably arranged for side-sealing. The carton sheets 2 are individually fed onto the conveyor 100 and conveyed forward by a first drive station 110. The conveyor 100 may comprise a number of different stations 120, 130, 140, 150, 160, 170, 180, and 190, each with conveyor drive belts 121, 131, 141, 151, 161, 171, 181, and 191, respectively, conveying each carton sheet 2a forward through each station and into the next subsequent station. Each station 120, 130, 140, 150, 160, 170, 180, and 190 may, as described above, include side-sealing equipment 122, 132, and 192 arranged to apply adhesive tapes, glues, or staples to the carton sheets as they are conveyed through each respective station.

[0005] At the end of the conveyor 100 is a final ejector station 200. The final ejector station 200 is typically equipped with a mechanical arrangement 210, 211 designed to eject carton sheets that have been affected by defects. The mechanical arrangement 210, 211 may include, for example, a mechanical arm or finger (not shown) arranged to physically contact the defective carton sheets and push them through an ejection chute 220 into a collection bin 230.

[0006] However, a common cause of unplanned stoppages in this type of conveyor is the jamming of carton sheets earlier along the conveyor. Besides leading to costly production delays, this can also damage machine parts, such as drive belts, rollers, and bearings in the various stations, which may be expensive to replace. Thus, there is a need to avoid such jams in the conveyor system and improve the handling of carton sheets being transported along a conveyor.Summary

[0007] It is an object of the invention to at least partly overcome one or more of the above-identified limitations of the prior art. In particular, it is an object to improve the handling of carton sheets being transported on a conveyor.

[0008] To achieve these objectives, an ejection arrangement for ejecting misaligned carton sheets being transported in a transportation direction on a conveyor with an ejection opening located below the conveying surface of the conveyor is provided. The ejection arrangement comprises a sensor configured to generate signals indicative of the presence of carton sheets being transported on the conveyor. The ejection arrangement also includes an air expulsion unit arranged to be mounted above the ejection opening and configured to expel air bursts downward onto the carton sheets being transported on the conveyor. Further, the ejection arrangement includes a control unit configured to: receive the signals from the sensor; determine, based on the received signals, whether a carton sheet is misaligned by analyzing its rotation and / or whether the carton sheet is overlapping another carton sheet; and control the air expulsion unit to expel air bursts at misaligned carton sheets, thereby diverting the misaligned carton sheets from the conveyor into the ejection opening.

[0009] By having an ejection arrangement as described above, non-contact ejection of misaligned carton sheets without speed loss anywhere along the conveyor is enabled. Since no mechanical ejection arrangement physically contacts the misaligned carton sheets during the ejection process, avoiding the risk of scratching or damaging other carton sheets on the conveyor or causing further misalignment, this non-contact ejection is more reliable. Hence, the handling of carton sheets being transported on a conveyor is improved.

[0010] In some embodiments, the conveyor may comprise a first conveyor section and a second conveyor section, spaced apart to form a gap between them, with the ejection opening defined by this gap. A technical benefit here is that the ejection arrangement can be suitably positioned between any two conveyor sections along the conveyor, allowing it to be advantageously placed early in the production line. This positioning is particularly beneficial because detecting and ejecting misaligned carton sheets sooner reduces the likelihood of costly damage later in the production line. For example, by positioning the ejection arrangement before a heater section using vacuum belts as part of a side-sealing process, potential damage to the vacuum belts in the heater section may be prevented. Such vacuum belts are commonly damaged components in heater sections and are expensive to replace.

[0011] In some embodiments, the ejection opening may include one or more rollers arranged to guide misaligned carton sheets that are diverted into the ejection opening. A technical benefit here is that the rollers support the diverted carton sheets, ensuring continuous, guided, and controlled movement through the ejection opening.

[0012] In some embodiments, the ejection opening may comprise an ejection conveyor section arranged to move the misaligned carton sheets that are diverted into the ejection opening. A technical benefit here is that the ejection conveyor section ensures continuous forward motion of the carton sheets through the ejection opening by conveying the misaligned sheets hit by the air bursts downward into contact with the ejection conveyor section.

[0013] In some embodiments, the ejection conveyor section and the one or more rollers may be arranged opposite each other to create a channel for feeding the misaligned carton sheets diverted into the ejection opening toward a waste disposal unit. A technical benefit here is that the cooperative positioning of the ejection conveyor section and rollers provides controlled movement and a guided path for the carton sheets all the way to the waste disposal unit.

[0014] In some embodiments, the ejection conveyor section may comprise a section arranged below the conveying surface and parallel to the transportation direction of the conveyor, and configured to move in a direction opposite to the transportation direction of the conveyor. A technical benefit here is that the continuous forward motion of the carton sheets down the ejection opening is facilitated while ensuring that the transportation of the remaining aligned carton sheets along the conveying surface is not disturbed.

[0015] In some embodiments, the ejection opening may comprise a fixed guide plate that is tilted downward in the transportation direction of the conveyor to guide misaligned carton sheets that are diverted into the ejection opening. A technical benefit here is that the carton sheets are not bent too much due to the downward force exerted by the air bursts from the air expulsion unit before being supported by the roller. Thus, the fixed guide plate prevents the carton sheets from being fed on the wrong side of the rollers.

[0016] In some embodiments, the conveyor may comprise a first lower conveyor section and a second lower conveyor section, with the second lower conveyor section spaced apart from the first lower conveyor section in the transportation direction, forming a lower gap between the lower sections. Additionally, the conveyor may comprise a first upper conveyor section and a second upper conveyor section, with the second upper conveyor section spaced apart from the first upper conveyor section in the transportation direction, forming an upper gap between the upper sections. The first upper conveyor section may be arranged above the first lower conveyor section to feed the carton sheets in the transportation direction between the first upper and lower conveyor sections. Similarly, the second upper conveyor section may be arranged above the second lower conveyor section to feed carton sheets that are not diverted into the ejection opening in the transportation direction between the second upper and lower conveyor sections. The ejection opening may be defined by the lower gap, and the air expulsion unit may be arranged in the upper gap. A technical benefit here is that the combined configuration of the sections provides suitable positioning of the air expulsion unit relative to the ejection opening, while the upper and lower conveyors sandwich the carton sheets, enhancing control and reliability of their conveyance.

[0017] In some embodiments, the control unit may be configured to determine that a carton sheet is misaligned due to rotation on the conveyor, based on whether there is a predetermined offset in the detected arrival or departure time of the carton sheet between at least two detection points located on opposite sides of the conveyor. A technical benefit here is that one of the most common displacements of carton sheets-unwanted rotation-can be instantly and easily detected and acted upon.

[0018] In some embodiments, the control unit may be configured to determine that a carton sheet is misaligned due to overlapping another carton sheet on the conveyor, based on whether the time between the detected arrival and departure times for the sheet exceeds a predetermined threshold. A technical benefit here is that another common displacement of carton sheets-unwanted overlap-can be instantly and easily detected and acted upon.

[0019] In some embodiments, the ejection arrangement may be configured to operate when the conveyor transports carton sheets at a speed greater than 100 meters per minute, or at a speed in the range of 300 to 600 meters per minute. A technical benefit here is that the ejection arrangement is particularly well-suited for high-speed conveyors and mass production of carton sheets. It should be noted that these conveyor transport speeds are representative of the exemplified embodiments, and speeds outside these ranges are not excluded from the scope of protection herein.

[0020] Additionally, to further achieve these objectives, a method in a control unit of an ejection arrangement for ejecting misaligned carton sheets being transported in a transportation direction on a conveyor with an ejection opening below the conveying surface is also provided. The method comprises receiving signals from a sensor indicative of the presence of carton sheets. The method also includes determining, based on the received signals, whether a carton sheet is misaligned by analyzing its rotation and / or whether it is overlapping another carton sheet. Additionally, the method includes controlling an air expulsion unit to expel air bursts downward at misaligned carton sheets, thereby diverting them from the conveyor into the ejection opening.

[0021] According to some embodiments, determining whether a carton sheet is misaligned due to rotation on the conveyor may further comprise detecting the arrival or departure time of the carton sheet at least two detection points located on opposite sides of the conveyor, calculating a predetermined offset between the detected arrival or departure times, and determining, based on the offset, that the carton sheet is misaligned due to rotation.

[0022] In some embodiments, determining whether a carton sheet is misaligned may further comprise detecting the arrival and departure times of a carton sheet on the conveyor, calculating the time between these times, and determining, based on whether the calculated time exceeds a predetermined threshold, that the carton sheet is misaligned due to overlapping another carton sheet.

[0023] Other objectives, features, aspects, and advantages of the invention will appear from the following detailed description and from the drawings.Drawings

[0024] Embodiments of the invention will now be described, by way of example, with reference to the accompanying schematic drawings, in which: Fig. 1 is a perspective side view of a conveyor. Fig. 2 illustrates an example of how carton sheets are preferably aligned during transport on a conveyor. Fig. 3a-b illustrates examples of how carton sheets may be misaligned during transport on a conveyor. Fig. 4 is a perspective side view illustrating an example of the position of embodiments of an ejection arrangement in a conveyor. Fig. 5-6 illustrate how embodiments of an ejection arrangement detect and handle misaligned carton sheets on a conveyor. Fig. 7 is a perspective side view of embodiments of an ejection arrangement. Fig. 8 is a flowchart depicting embodiments of a method in a control unit of an ejection arrangement. Fig. 9 illustrates embodiments of an ejection arrangement. Description

[0025] With reference to Fig. 2, an example of how carton sheet(s) 2, e.g. the carton sheets 2a, 2b, 2c, 2d, may be aligned during transport on a conveyor 100 is illustrated. The carton sheets 2a, 2b, 2c, 2d are normally transported on the conveyor 100 in a transportation direction D with a gap or spacing 102 between them.

[0026] It has been realized, as part of the development of the embodiments described herein, that one of the main causes of jamming of carton sheets 2a, 2b, 2c, 2d on a conveyor 100 is that some carton sheets 2a, 2b, 2c, 2d become misaligned and thus lie in an incorrect position while being conveyed on the conveyor 100. It has further been observed that two of the most common types of misalignment may be referred to as double blanks and rotated blanks. An example of a double blank misalignment is shown in Fig. 3a, where two carton sheets 2k, 2j have accidentally wound up on top of each other, causing overlap. This may occur due to uneven feeding of the carton sheets 2k, 2j or if carton sheet 2j is caught on some part of the conveyor 100, sliding on top of carton sheet 2k. An example of a rotated blank misalignment is shown in Fig. 3b, where two carton sheets 2l, 2m have been rotated relative to their intended alignment, as shown in Fig. 2. This results in the front edges of carton sheets 2l, 2m no longer being perpendicular to the transportation direction D, i.e., parallel to the frame of the conveyor 100.

[0027] As illustrated in Fig. 4, these issues are addressed by the embodiments described below, which introduce an ejection arrangement 1 capable of detecting misaligned carton sheets on a conveyor and, using an air expulsion unit 40 with compressed air and well-timed, quick-reaction valves, ejecting the misaligned sheets down into an ejection opening for disposal in a waste disposal unit 300.

[0028] Figs. 5-6 show how misaligned carton sheets on a conveyor 10 may be detected and handled by embodiments of an ejection arrangement 1.

[0029] In Fig. 5, for example, carton sheets 2 are conveyed on a first conveyor section 12 in the transport direction D, i.e., from left to right in Fig. 5. The first conveyor section 12 may comprise one or more conveyor belts 12a, 12b, depicted as dashed areas in Fig. 5. The conveyor belts 12a, 12b operate at the same transportation speed D1 while conveying the carton sheets 2 in the transportation direction D.

[0030] As the carton sheets 2 move toward the ejection opening 11 on the conveyor belts 12a, 12b of the first conveyor section 12, they pass below or within view of a sensor 30. The sensor 30 is configured to generate signals indicative of the presence of carton sheets 2 being transported on the conveyor 10. The sensor 30 may, for example, have two detection points 30a, 30b located on opposite sides of the conveyor 10, configured to generate signals indicating the presence of a carton sheet on respective conveyor belts 12a, 12b of the first conveyor section 12. Here, "presence" refers to the detection by the sensor 30 of a carton sheet at specific locations on the conveyor section 12 during its transportation in the transport direction D. Thus, the sensor 30 is configured to generate signals indicating the arrival and departure of the carton sheets 2 at detection points 30a, 30b. These sensor signals may then be used by a control unit 50 (shown in Fig. 7 and 9) to analyze potential misalignment, such as rotation or overlap of the carton sheets 2.

[0031] In the example shown in Fig. 5, the control unit 50 may, based on signals from the sensor 30, determine if there is a time offset between the detection of the carton sheets 2 at the two detection points 30a, 30b, e.g., a time offset corresponding to a measured length X > 0, such as > 1 mm or > 2 mm. If so, the control unit 50 may determine that a carton sheet, as illustrated by carton sheet 2i, has rotated relative to its original transportation orientation. However, if there is no significant time offset, e.g., a time offset corresponding to a measured length X = 0, or alternatively <= 1 mm or <= 2 mm, the control unit 50 may determine that a carton sheet, as illustrated by carton sheet 2b, has maintained its original orientation, with the edges 420a, 421a of carton sheet 2b remaining parallel to the transportation direction D as it is conveyed on the conveyor 10. Here, "no significant time offset" may correspond to a time offset that is zero or approximately zero, such as a measured length X = Δ, where Δ = 0-1 mm. In other words, the control unit 50 may determine that a carton sheet 2i is misaligned due to rotation on the conveyor 10, based on whether there is a time offset, e.g., a time offset corresponding to a measured length X > 0, in the detected arrival or departure time of the carton sheet 2i between at least two detection points 30a, 30b located on opposite sides of the conveyor 10. Here, it should be noted that the time offset may correspond to a time offset that is above zero or above approximately zero, such as, e.g. a time offset corresponding to a measured length in a range of X > Δ, wherein Δ = 0-1mm. This time offset limit may be set or configured upon startup and / or adjusted based on the transportation speed D1.

[0032] Once the control unit 50 determines that a carton sheet, such as 2i in Fig. 5, has rotated, it may control the air expulsion unit 40 to expel air bursts at the misaligned carton sheet 2i as it passes over the ejection opening 11 and prior to reaching the second conveyor section 13. Thus, the misaligned carton sheet 2i may be diverted from the transportation direction D of the conveyor 10 and directed down into the ejection opening 11. This process may, in some embodiments, be assisted by an ejection conveyor section 16, depicted as the double-dashed areas in Fig. 5. The ejection conveyor section 16 may include a conveyor belt rotating in the opposite direction of the transportation direction D at a speed D2. The ejection conveyor section 16 is described in more detail below with reference to Fig. 7.

[0033] Also, if the control unit 50 determines that a carton sheet has maintained its original orientation (i.e., has not rotated), the control unit 50 will refrain from activating the air expulsion unit 40 to expel air bursts at the aligned carton sheet 2b as it passes over the ejection opening 11, allowing it to reach the second conveyor section 13, as illustrated by the aligned carton sheet 2f. These aligned carton sheets 2a, 2b, and 2f will then be further conveyed by the one or more conveyor belts 13a, 13b of the second conveyor section 13 in the transport direction D. The conveyor belts 13a, 13b of the second conveyor section 13 operate at the same transportation speed D1 as the conveyor belts 12a, 12b of the first conveyor section 12 and are depicted as dashed areas in Fig. 5.

[0034] In Fig. 6, similarly, the carton sheets 2 are being conveyed on a first conveyor section 12 in the transport direction D, i.e., from left to right in Fig. 6. In this example, the control unit 50 may, based on the signals from the sensor 30, determine if there is a time difference between the arrival and departure of carton sheet 2a at one of the detection points 30a, 30b that is above a predetermined threshold or threshold level. The predetermined threshold may correspond to the length of a single carton sheet, e.g., Y = L, or approximately L. Hence, if the time difference between the arrival and departure of carton sheet 2a at one of the detection points 30a, 30b is above the predetermined threshold, i.e., the time difference corresponds to a length longer than a single carton sheet, e.g., Y > L or significantly larger than L, the control unit 50 may determine that a carton sheet, as illustrated by carton sheets 2k and 2j, has moved from its intended transportation position on the conveyor belts 12a, 12b to overlap another carton sheet 2. In other words, the control unit 50 may determine that carton sheet 2j is misaligned due to overlapping another carton sheet 2k on the conveyor 10, based on whether the time between the detected arrival time and departure time for carton sheet 2j exceeds a predetermined threshold, e.g., a time corresponding to a length Y > L. However, if the time difference between the arrival and departure of the carton sheet at one of the detection points 30a, 30b is not above the predetermined threshold, e.g., a time corresponding to a length Y = L, the control unit 50 may determine that carton sheet 2b has maintained its intended transportation position on the conveyor belts 12a, 12b. Here, it should be noted that "approximately L" may correspond to Y = L + α, where α = 0 to 5 mm; correspondingly, "significantly larger than L" may correspond to Y > L + α, where α = 0 to 5 mm.

[0035] Once a carton sheet has been determined by the control unit 50 to have overlapped another carton sheet, such as carton sheet 2j overlapping carton sheet 2k in Fig. 6, the control unit 50 may control the air expulsion unit 40 to expel air bursts at both misaligned carton sheets 2j and 2k as they pass over the ejection opening 11 and prior to reaching the second conveyor section 13. Thus, the misaligned carton sheets 2j and 2k may be diverted from transportation direction D of the conveyor 10 and down into the ejection opening 11. Correspondingly, if a carton sheet has been determined by the control unit 50 to have maintained its intended transportation position on the conveyor belts 12a, 12b, i.e., not overlapping another carton sheet, the control unit 50 will refrain from controlling the air expulsion unit 40 to expel air bursts at aligned carton sheet 2b as it passes over the ejection opening 11, allowing it to reach the second conveyor section 13, as illustrated by aligned carton sheet 2f. These aligned carton sheets 2a, 2b, and 2f will then be further conveyed by conveyor belts 13a, 13b of the second conveyor section 13 in the transport direction D.

[0036] Fig. 7 shows a side view of embodiments of an ejection arrangement 1 for carton sheets 2 being transported in a transportation direction D on a conveyor 10.

[0037] In Fig. 7, a first conveyor section 12, 14 is arranged to convey the carton sheets 2 in the transportation direction D along the conveyor belts 12a, 12b with a transportation speed D1, for example, using one or more machine-driven rollers 121, 122, 123. Optionally, the first conveyor section 12, 14 may comprise a first lower conveyor section 12 and a first upper conveyor section 14. In this case, the first upper conveyor section 14 may also convey the carton sheets 2 in the transportation direction D along the conveyor belts 14a, 14b with the same transportation speed D1, for example, using one or more machine-driven rollers 141, 142.

[0038] Also, a second conveyor section 13, 15 is arranged spaced apart from the first conveyor section 12, 14, thus forming a gap 118 between the first conveyor section 12, 14 and the second conveyor section 13, 15. The gap 118 defines an ejection opening 11 between the first conveyor section 12, 14 and the second conveyor section 13, 15. The ejection opening 11 is located below the conveying surface of the conveyor 10. The conveying surface may be defined by the upper side of the conveyor belts 12a, 12b of the first conveyor section 12 and the conveyor belts 13a, 13b of the second conveyor section 13 upon which the carton sheets 2 rest while being conveyed in the transportation direction D, i.e., a surface plane parallel to the transportation direction D.

[0039] The second conveyor section 13, 15 is arranged to receive the carton sheets 2 from the first conveyor section 12, 14 over the gap 118 and continue to convey them in the transportation direction D along the conveyor belts 13a, 13b with the same transportation speed D1, for example, using one or more machine-driven rollers 131, 132, 133. Optionally, the second conveyor section 13, 15 may comprise a second lower conveyor section 13 and a second upper conveyor section 15. In this case, the second upper conveyor section 15 may also be arranged to receive the carton sheets 2 from the first conveyor section 12, 14 over the gap 118 and continue to convey them in the transportation direction D along the conveyor belts 15a, 15b with the same transportation speed D1, for example, using one or more machine-driven rollers 151, 152.

[0040] The ejection arrangement 1 in Fig. 7 comprises a sensor 30, an air expulsion unit 40, and a control unit 50.

[0041] The sensor 30 may be configured to generate signals S1 indicative of the presence of carton sheets 2 being transported on the conveyor 10. Although examples of the sensor 30 for detecting the presence of the carton sheets 2 on the conveyor 10 may include photoelectric sensors or similar simple sensors, it should be noted that the sensor 30 may be any type of sensor, such as one or more cameras, capable of detecting the presence of carton sheets 2 on the conveyor 10.

[0042] The air expulsion unit 40 may be arranged to be mounted above the ejection opening 11 and configured to expel air bursts 42 downward onto the carton sheets 2 being transported on the conveyor 10. As shown in Fig. 7, this means that the air expulsion unit 40 may be mounted in the upper gap 119 formed by the space between the first upper conveyor section 14 and the second upper conveyor section 15. The air expulsion unit 40 may also be arranged to expel the air bursts 42 downward onto the carton sheets 2 across the entire width or specific parts of the width of the conveyor 10. The air expulsion unit 40 may also be referred to as "air knives" since the air bursts 42 may be expelled through several narrow air nozzles, creating a curtain of air flowing downward onto the carton sheets 2. By using compressed air with well-timed, quick-reaction valves in the air expulsion unit 40, misaligned carton sheets, such as the misaligned carton sheets 2d, 2e in Fig. 7, may be ejected down into the ejection opening 11 without affecting other carton sheets, such as carton sheets 2a-c and 2f-g in Fig. 7, being conveyed along the conveyor 10.

[0043] The control unit 50 may be configured to receive the signals S1 from the sensor 30 and determine, based on the received signals S1, whether a carton sheet 2 is misaligned by analyzing its rotation and / or whether the carton sheet is overlapping another carton sheet. Then, the control unit 50 may be configured to control the air expulsion unit 40 to expel air bursts at misaligned carton sheets 2, e.g., the misaligned carton sheets 2d, 2e in Fig. 7, thereby diverting the misaligned carton sheets 2 from the conveyor 10 into the ejection opening 11. This may be performed by the control unit 50 by sending control signals C1 to the air expulsion unit 40, in response to which the air expulsion unit 40 may actuate the expulsion of the air bursts 42. The control unit 50 is described in more detail with reference to Fig. 9 below.

[0044] As shown by the ejection arrangement 1 in Fig. 7, the ejection opening 11 may, for example, comprise a fixed guide plate 115 and / or one or more rollers 111-113. The fixed guide plate 115, e.g., a mounted metal plate, may be tilted downward in the transportation direction D to guide the carton sheets 2, e.g., the misaligned carton sheets 2d, 2e in Fig. 7, that are diverted into the ejection opening 11. As shown in Fig. 7, the fixed guide plate 115 may guide the carton sheets 2d, 2e toward one or more rollers 111-113. The rollers 111-113 are also arranged to guide and transport the carton sheets 2d, 2e that are diverted into the ejection opening 11. The rollers 111-113 may be so-called friction-driven or zero-crush rollers and may guide and transport the carton sheets 2d, 2e to a waste disposal unit 300.

[0045] Furthermore, the ejection opening 11 may also comprise an ejection conveyor section 16 arranged to move carton sheets 2, e.g., the misaligned carton sheets 2d, 2e in Fig. 7, that are diverted into the ejection opening 11. The ejection conveyor section 16 may, for example, comprise a conveyor belt 165 run by machine-driven rollers 161, 162, 163 at a transportation speed D2, and may be arranged as a standalone unit or be integrated into the second lower conveyor section 13. As shown in Fig. 7, as the misaligned carton sheets 2d, 2e are diverted down into the ejection opening 11 by the air bursts 42 from the air expulsion unit 40, the transportation speed D1 of the misaligned carton sheets 2d, 2e will bring them into contact with the conveyor belt 165, which will convey / feed the misaligned carton sheets 2d, 2e further down toward the waste disposal unit 300. The ejection conveyor section 16 may be arranged opposite the rollers 111-113 to create a channel 114 for feeding the misaligned carton sheets 2d, 2e that are diverted into the ejection opening 11 toward the waste disposal unit 300. The ejection conveyor section 16 may also comprise a section that is arranged below the conveying surface and parallel to the transportation direction D of the conveyor 10, and is configured to move in a direction opposite to the transportation direction D of the conveyor 10, e.g., the part of the conveyor belt 165 that is parallel with and runs in the opposite direction of the transportation direction D in Fig. 7.

[0046] It should be noted that the ejection conveyor section 16 may also be arranged closer to the first lower conveyor section 12 than to the second lower conveyor section 13. This may ensure, for example, that the misaligned carton sheets 2d, 2e that are diverted into the ejection opening 11 will contact the conveyor belt 165 of the ejection conveyor section 16 instead of the conveyor belts 13a, 13b of the second lower conveyor section 13.

[0047] It should also be noted that the ejection arrangement 1 is configured to operate when the conveyor 10 transports the carton sheets 2 at a transportation speed D1 greater than 100 meters per minute, or at a transportation speed D1 in the range of 300 to 600 meters per minute. Additionally, the transportation speed D2 of the conveyor belt 165 in the second lower conveyor section 13 preferably matches the transportation speed D1 of the conveyor 10.

[0048] Examples of a method 800 for ejecting misaligned carton sheets being transported in a transportation direction D on a conveyor 10 with an ejection opening 11 located below the conveying surface of the conveyor 10 will now be described with reference to the flowchart in Fig. 8. Fig. 8 illustrates actions (also referred to as "operations", or "steps"). that may be taken by the control unit 50 in the ejection arrangement 1, as shown in Figs. 4-7. The method may comprise the following actions: Action 801: The control unit 50 receives signals S1 from a sensor 30 indicative of the presence of carton sheets 2. This means that the control unit 50 may detect the presence of carton sheets 2 being transported on the conveyor 10 using a sensor 30 configured to generate signals indicative of the presence of the carton sheets 2.

[0049] Action 802: After receiving signals S1 in Action 801, the control unit 50 determines, based on the received signals S1, whether a carton sheet is misaligned by analyzing its rotation and / or whether the carton sheet is overlapping another carton sheet.

[0050] Optionally, the control unit 50 may determine that a carton sheet is misaligned due to rotation on the conveyor 10 by, in Action 802a, detecting the arrival or departure time of the carton sheet 2 at least two detection points 30a, 30b located on opposite sides of the conveyor 10. Then, in Action 802b, the control unit 50 may calculate a predetermined offset, X > 0, between the detected arrival or departure times of the carton sheet at detection points 30a, 30b. In Action 802c, the control unit 50 may then determine, based on the predetermined offset, X > 0, that the carton sheet 2i is misaligned due to rotation.

[0051] Alternatively, the control unit 50 may determine that a carton sheet is misaligned by, in Action 802d, detecting the arrival and departure times of a carton sheet 2j on the conveyor 10. Then, in Action 802e, the control unit 50 may calculate the time between the detected arrival and departure times of the carton sheet 2j. In Action 802f, the control unit 50 may then determine, based on whether the calculated time exceeds a predetermined threshold, Y > L, that the carton sheet 2j is misaligned due to overlapping another carton sheet 2k.

[0052] Action 803: After determining the misalignment in Action 802, the control unit 50 controls the air expulsion unit 40 to expel air bursts 42 downward at misaligned carton sheets, thereby diverting the misaligned carton sheets from the conveyor 10 into the ejection opening 11. This may be performed by sending control signals C1 to the air expulsion unit 40. The air expulsion unit 40 will thus receive the control signals C1 from the control unit 50 and actuate the expulsion of the air bursts 42 based on the control signals C1.

[0053] To perform the method actions in the ejection arrangement 1 for ejecting misaligned carton sheets 2 being transported in a transportation direction D on a conveyor 10 with an ejection opening 11 located below the conveying surface of the conveyor 10, the ejection arrangement 1 may comprise the arrangement depicted in Fig. 9. Fig. 9 shows a schematic block diagram of examples of the ejection arrangement 1. The ejection arrangement 1 comprises a sensor 30, an air expulsion unit 40, and a control unit 50.

[0054] The sensor 30 is configured to generate signals S1 indicative of the presence of the carton sheets 2 and send the signals S1 to the control unit 50.

[0055] The control unit 50 may comprise processing circuitry or processor 51 and a memory 52. The processing circuitry 51 may also include a detecting module 51a, a determining module 51b, and a controlling module 51c. The control unit 50 or processing circuitry 51 is configured to, or may include, the detecting module 51a configured to detect the presence of carton sheets 2 being transported on the conveyor 10 by receiving signals S1 from the sensor 30. Additionally, the control unit 50 or processing circuitry 51 is configured to, or may include, the determining module 51b configured to determine, based on the received signals S1, whether a carton sheet is misaligned by analyzing its rotation and / or whether the carton sheet is overlapping another carton sheet. Further, the control unit 50 or processing circuitry 51 is configured to, or may include, the controlling module 51c configured to control the air expulsion unit 40 to expel air bursts 42 downward at misaligned carton sheets, thereby diverting the misaligned carton sheets from the conveyor 10 into the ejection opening 11. The controlling module 51c in the control unit 50 or processing circuitry 51 may be configured to send control signals C1 to the air expulsion unit 40.

[0056] The air expulsion unit 40 is configured to receive the control signals C1 from the control unit 50 and actuate the expulsion of the air bursts 42 based on the control signals C1.

[0057] Furthermore, the examples for ejecting misaligned carton sheets 2 being transported in a transportation direction D on a conveyor 10 with an ejection opening 11 located below the conveying surface of the conveyor 10, as described above, may partly be implemented through one or more processors, such as the processing circuitry 51 in the control unit 50 depicted in Fig. 9, together with computer program code for performing the functions and actions of the embodiments herein. The program code mentioned above may also be provided as a computer program product, for instance in the form of a data carrier carrying computer program code or code means for performing the embodiments herein when loaded into the processing circuitry 51 in the control unit 50. The computer program code may, for example, be provided as pure program code in the control unit 50 or on a server and downloaded to the control unit 50. Thus, it should be noted that the modules of the control unit 50 may, in some embodiments, be implemented as computer programs stored in memory, e.g., in the memory module 52 in Fig. 9, for execution by processors or processing modules, e.g., the processing circuitry 51 in Fig. 9.

[0058] Those skilled in the art will also appreciate that the processing circuitry 51 and memory 52 described above may refer to a combination of analog and digital circuits, and / or one or more processors configured with software and / or firmware, e.g., stored in memory, that, when executed by the one or more processors such as the processing circuitry 51, perform as described above. One or more of these processors, as well as other digital hardware, may be included in a single application-specific integrated circuit (ASIC), or several processors and various digital hardware may be distributed among several separate components, whether individually packaged or assembled into a single chip.

[0059] From the description above, it follows that, although various embodiments of the invention have been described and shown, the invention is not restricted thereto but may also be embodied in other ways within the scope of the subject matter defined in the following claims.

Claims

1. An ejection arrangement (1) for ejecting misaligned carton sheets being transported in a transportation direction (D) on a conveyor (10) having an ejection opening (11) located below the conveying surface of the conveyor (10), and the ejection arrangement (1) comprising: a sensor (30) configured to generate signals (S1) indicative of the presence of carton sheets (2) being transported on the conveyor (10); an air expulsion unit (40) arranged to be mounted above the ejection opening (11) and configured to expel air bursts (42) downward onto the carton sheets (2) being transported on the conveyor (10); and a control unit (50) configured to - receive the signals (S1) from the sensor (30), - determine, based on the received signals (S1), whether a carton sheet is misaligned by analyzing its rotation and / or whether the carton sheet is overlapping another carton sheet, and - control the air expulsion unit (40) to expel air bursts at misaligned carton sheets (2d, 2e), thereby diverting the misaligned carton sheets (2d, 2e) from the conveyor (10) into the ejection opening (11).

2. The ejection arrangement (1) according to claim 1, wherein the conveyor (10) comprises a first conveyor section (12) and a second conveyor section (13), which are spaced apart to form a gap (118) between the conveyor sections (12, 13), and the ejection opening (11) is defined by the gap (118) between the first and second conveyor sections (12, 13).

3. The ejection arrangement (1) according to any preceding claim, wherein the ejection opening (11) comprises one or more rollers (111-113) arranged to guide the misaligned carton sheets (2d, 2e) that are diverted into the ejection opening (11).

4. The ejection arrangement (1) according to any preceding claim, wherein the ejection opening (11) comprises an ejection conveyor section (16) arranged to move the misaligned carton sheets (2d, 2e) that are diverted into the ejection opening (11).

5. The ejection arrangement (1) according to claims 3 and 4, wherein the ejection conveyor section (16) and the one or more rollers (111-113) are arranged opposite each other to create a channel (114) for feeding the misaligned carton sheets (2d, 2e) that are diverted into the ejection opening (11) toward a waste disposal unit (300).

6. The ejection arrangement (1) according to claim 4 or 5, wherein the ejection conveyor section (16) comprises a section (165) that is arranged below the conveying surface and parallel to the transportation direction (D) of the conveyor (10), and is configured to move in a direction that is opposite to the transportation direction (D) of the conveyor (10).

7. The ejection arrangement (1) according to any preceding claim, wherein the ejection opening (11) comprises a fixed guide plate (115) that is tilted downwards in the transportation direction (D) of the conveyor (10) to guide the misaligned carton sheets (2d, 2e) that are diverted into the ejection opening (11).

8. The ejection arrangement (1) according to any preceding claim, wherein the conveyor (10) comprises a first lower conveyor section (12) and a second lower conveyor section (13), the second lower conveyor section (13) being spaced apart from the first lower conveyor section (12) in the transportation direction (D), forming a gap (118) between the lower conveyor sections (12, 13), a first upper conveyor section (14) and a second upper conveyor section (15), the second upper conveyor section (15) being spaced apart from the first upper conveyor section (14) in the transportation direction (D), forming an upper gap (119) between the upper conveyor sections (14, 15), wherein the first upper conveyor section (14) is arranged above the first lower conveyor section (12) for feeding the carton sheets (2) in the transportation direction (D) between the first upper conveyor section (14) and the first lower conveyor section (12), the second upper conveyor section (15) is arranged above the second lower conveyor section (13) for feeding carton sheets (2f, 2g) that are not diverted into the ejection opening (11), in the transportation direction (D) between the second upper conveyor section (15) and the second lower conveyor section (13), the ejection opening (11) is defined by the gap (118), and the air expulsion unit (40) is arranged in the upper gap (119).

9. The ejection arrangement (1) according to any preceding claim, wherein the control unit (50) is configured to determine that a carton sheet (2i) is misaligned due to being rotated on the conveyor (10), based on whether there is a predetermined offset (X>0) in detected arrival or departure time of the carton sheet between at least two detection points (30a, 30b) that are located a respective opposite side of the conveyor (10).

10. The ejection arrangement (1) according to any preceding claim, wherein the control unit (50) is configured to determine that a carton sheet (2j) is misaligned due to overlapping another carton sheet (2k) on the conveyor (10), based on whether the time between a detected arrival time and departure time for the carton sheet (2j) exceeds a predetermined threshold (Y>L).

11. The ejection arrangement (1) according to any preceding claim, wherein the ejection arrangement (1) is configured to operate when the conveyor (10) transports the carton sheets (2) at a speed (D1, D2) greater than 100 meters per minute, or at a speed in the range of 300 to 600 meters per minute.

12. A method (800) performed by a control unit (50) of an ejection arrangement (1) for ejecting misaligned carton sheets being transported in a transportation direction (D) on a conveyor (10) having an ejection opening (11) located below the conveying surface of the conveyor (10), the method comprising receiving signals (S1) from a sensor (30) indicative of the presence of carton sheets (2), determining (802), based on the received signals (S1), whether a carton sheet is misaligned by analyzing its rotation and / or whether the carton sheet is overlapping another carton sheet, and controlling (803) an air expulsion unit (40) to expel air bursts (42) downward at misaligned carton sheets (2d, 2e), thereby diverting the misaligned carton sheets (2d, 2e) from the conveyor (10) into the ejection opening (11).

13. The method (800) according to claim 12, wherein determining (802) whether a carton sheet is misaligned due to being rotated on the conveyor (10) further comprises detecting (802a) the arrival or departure time of the carton sheet at least two detection points (30a, 30b) located on opposite sides of the conveyor (10), calculating (802b) a predetermined offset (X > 0) between the detected arrival or departure times of the carton sheet at the detection points (30a, 30b), and determining (802c), based on the predetermined offset (X > 0), that the carton sheet (2i) is misaligned due to being rotated.

14. The method (800) according to claim 12 or 13, wherein determining (802) whether a carton sheet is misaligned further comprises detecting (802d) the arrival and departure times of a carton sheet (2j) on the conveyor (10), calculating (802e) the time between the detected arrival and departure times of the carton sheet (2j), and determining (802f), based on whether the calculated time exceeds a predetermined threshold (Y > L), that the carton sheet (2j) is misaligned due to overlapping another carton sheet (2k).

15. A computer program product comprising program code which, when executed by processing circuitry (51) of a control unit (50) in an ejection arrangement (1), performs the method of any of claims 12-14.

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