Inspection device and manufacturing method for sheet roll

Abstract

To detect a defect generated in a tail end portion left adhered to an outer peripheral surface of a sheet roll.SOLUTION: An inspection device for a sheet roll R in which a root of a tail end portion T of a wound sheet is adhered to an outer peripheral surface includes: a blowing unit 20 for blowing a gas to the sheet roll R from a half portion side of the sheet roll R in which no tail end portion T is provided; and a detection unit 30 for detecting that the tail end portion T is separated from the outer peripheral surface and raised while the root is adhered to the outer peripheral surface by blowing of the gas.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to an inspection device for sheet rolls such as toilet rolls and a manufacturing method thereof. More specifically, the present invention relates to a technique for inspecting whether or not the tail end of a sheet roll is normally bonded to an outer peripheral surface. [Background technology]

[0002] 2. Description of the Related Art It has been known in the past to introduce an inspection device into, for example, a toilet roll manufacturing device, which detects adhesion defects at the tail end and automatically ejects the roll out of the conveying path (for example, Patent Document 1).

[0003] The device described in Patent Document 1 is said to be capable of detecting defective products with peeled tail ends during the process of conveying the sheet roll with its end face in the direction of travel. Specifically, in the device described in Patent Document 1, the sheet roll is conveyed toward the downstream side of the device while being turned in the circumferential direction while lying flat on the conveying surface of the conveyor. In addition, a pair of guide plates are erected on the conveying surface with a predetermined gap therebetween, and the sheet roll is conveyed while being guided by the pair of guide plates. At this time, if the tail end of the sheet roll is peeled off, the tail end is exposed to the outside of the guide plates through the gap between the conveying surface and the guide plates. In Patent Document 1, the tail end exposed to the outside of the guide plates in this way is detected by a sensor such as a photoelectric tube. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2009-103622 A Summary of the Invention [Problem to be solved by the invention]

[0005] Incidentally, the device described in Patent Document 1 basically detects the tail end as defective when the tail end is completely peeled off from the outer peripheral surface of the sheet roll. However, even if the tail end remains attached to the outer peripheral surface of the sheet roll, there are cases where the tail end is defective.

[0006] That is, it is appropriate that only the base portion of the tail end is bonded to the outer peripheral surface of the sheet roll, and the other portion is not bonded to the outer peripheral surface and functions as a gripping margin when peeling off the tail end. However, for example, if the adhesive is applied to the tail end in a larger amount than the specified amount during the manufacturing process of the sheet roll, the entire tail end is bonded to the outer peripheral surface of the sheet roll, and such a gripping margin may not be formed with a sufficient area. Also, if the position where the adhesive is applied is too close to the tip side of the tail end, the gripping margin will not be formed with a sufficient area. Even if the tail end is properly bonded to the outer peripheral surface of the sheet roll and a gripping margin with an appropriate area is formed, for example, the tail end may get caught somewhere on the manufacturing line or come into contact with another sheet roll, causing a part of the tail end to tear, chip, or bend. Since the device of Patent Document 1 is intended to detect a state in which the tail end has been completely peeled off from the outer peripheral surface of the sheet roll, there is a problem that it cannot detect defects that occur when the tail end remains bonded to the outer peripheral surface of the sheet roll.

[0007] SUMMARY OF THE PRESENT EMBODIMENTS The main object of the present invention is to detect defects occurring at the tail end of a sheet roll while it is still adhered to the outer peripheral surface of the sheet roll. [Means for solving the problem]

[0008] The inventor of the present invention has intensively studied means for achieving the above object, and has found that it is possible to detect the presence or absence of defects in the tail end bonded to the outer peripheral surface by blowing gas onto the sheet roll and detecting whether the tail end has risen appropriately from the outer peripheral surface. Based on the above findings, the inventor has come to the conclusion that the problems of the prior art can be solved, and has completed the present invention. The configuration and steps of the present invention will be specifically described below.

[0009] The first aspect of the present invention relates to an inspection device 100 for a sheet roll R. The sheet roll R is a continuous sheet wound in multiple layers. The sheet roll R has a tail end T on the outermost layer of the sheet, and in a normal state, the base of the tail end T is bonded to the outer peripheral surface of the sheet roll R. An example of such a sheet roll R is a toilet roll made by winding toilet paper, but is not limited to this. The inspection device 100 according to the present invention includes a blower unit 20 and a detector unit 30. The blower unit 20 is configured to blow gas onto the sheet roll R from the half of the sheet roll R where the tail end T is not provided (hereinafter also referred to as the "non-tail half"). As a result, the gas that hits the non-tail half of the sheet roll R flows around to the half of the sheet roll R where the tail end T is provided (hereinafter also referred to as the "tail half") and flows so as to raise the tail end T. The detection unit 30 is configured to detect that the tail end T has separated from the outer circumferential surface and risen while the base remains adhered to the outer circumferential surface as a result of the blowing of gas. Note that the blowing of gas onto the sheet roll R and the inspection of the rise of the tail end T may be performed in a state where the end face of the sheet roll R is in contact with a flat surface such as a conveying surface (i.e., the sheet roll R is in an upright state), or may be performed in a state where the circumferential surface of the sheet roll R is in contact with a flat surface such as a conveying surface (i.e., the sheet roll R is in a lying state).

[0010] As in the above configuration, various defects occurring in the tail end T can be detected by blowing gas onto the sheet roll R and inspecting the rising of the tail end T. Specifically, if the tail end T rises properly by blowing gas onto the sheet roll R, the tail end T can be determined to be normal. On the other hand, if the tail end T does not rise even by blowing gas, it can be determined that there is a defect, for example, when applying adhesive, and there is a defect such as no gripping margin being formed at the tail end T or the width of the gripping margin being extremely narrow. In addition, if the base (adhesive portion G) of the tail end T peels off from the outer peripheral surface of the sheet roll R due to blowing gas, it can be determined that there is a defect such as adhesive not being applied properly to the tail end T.

[0011] In the inspection device 100 according to the present invention, it is preferable that the tail end T is maintained in an upright state away from the outer peripheral surface of the sheet roll R while gas is being blown against it by the blower 20. In this case, the detection unit 30 may detect the tail end T in the upright state. In this way, by maintaining the tail end T in an upright state while gas is being blown against it by the blower 20, it becomes easier for the detection unit 30 to detect the tail end T.

[0012] The inspection device 100 according to the present invention preferably further includes a conveying unit 10 that conveys the sheet roll R. In this case, the blower unit 20 is preferably configured to blow gas onto the sheet roll R when the sheet roll R is being conveyed by the conveying unit 10 in an upright state. By blowing gas onto the sheet roll R while it is being conveyed by the conveying unit 10, it is possible to continuously inspect a plurality of sheet rolls R. In addition, by blowing gas onto the sheet roll R in an upright state, the tail end T is likely to become free, making it easier to detect the upright state of the tail end T.

[0013] In the inspection device 100 according to the present invention, the detection unit 30 may include an optical sensor 33 that emits inspection light. In this case, the optical sensor 33 may be one that detects that the tail end T that has peeled off from the outer circumferential surface has come into contact with the inspection light. This makes it possible to detect the rising of the tail end T with a relatively simple configuration.

[0014] In the inspection device 100 according to the present invention, the detection unit 30 may include an image sensor. For example, the image sensor may be incorporated in a planar camera 31 that photographs the end face side of the sheet roll R, or a side camera 32 that photographs the circumferential side of the sheet roll R. Alternatively, the image sensor may be one that photographs the sheet roll R from an oblique direction. This image sensor photographs the sheet roll R while gas is being blown onto it by the blower unit 20. By analyzing the image acquired by the image sensor, the movement of the tail end T of the sheet roll R due to the blowing of gas can be clarified. This allows the tail end T to be inspected in more detail for defects.

[0015] In the inspection device 100 according to the present invention, the image sensor included in the detection unit 30 is preferably arranged to capture an image of the end face of the sheet roll R. By capturing an image of the end face of the sheet roll R, it is possible to more accurately determine whether the tail end T is properly raised by blowing gas.

[0016] In the inspection device 100 according to the present invention, the image sensor included in the detection unit 30 is preferably arranged to capture an image of the peripheral surface of the sheet roll R. By capturing an image of the peripheral surface of the sheet roll R, it is possible to identify defects such as tears, chipping, and breakage that have occurred on the surface of the tail end T. It is difficult to determine the presence or absence of these defects from an image captured on the end face side of the sheet roll R, but they can be identified from an image captured on the peripheral surface side of the sheet roll R.

[0017] The inspection device 100 according to the present invention preferably further includes a storage unit for storing the captured image of the image sensor. The image stored in the storage unit may be stored in association with a correct answer label related to the success or failure of the tail end rising. In this case, the pair of the captured image and the correct answer label is used as teacher data for generating trained data by machine learning to be used for processing in the detection unit. In the present invention, the detection unit may detect that the tail end has risen away from the outer circumferential surface while the base is attached to the outer circumferential surface due to the blowing of gas, based on a trained model generated in advance by machine learning. At this time, it is efficient to store the captured image of the image sensor in the storage unit and use it for training the trained model, as described above.

[0018] In the inspection device 100 according to the present invention, the blower section 20 preferably includes a plurality of blowers 21. In particular, it is preferable that the plurality of blowers 21 blow gas onto the sheet roll R from a plurality of different directions. For example, in the process of continuously transporting a plurality of sheet rolls R, the tail end T of each sheet roll R may not be oriented in the same direction. In this case, by blowing gas onto each sheet roll R from a plurality of different directions, the tail end T can be made to stand up by blowing the gas, regardless of the direction in which the tail end T is oriented.

[0019] In the inspection device 100 according to the present invention, the air blowing section 20 may include one or more air blowers 21 and an air guide plate 22. The air guide plate 22 is arranged so as to guide the gas sent out from the air blower 21 to the sheet roll R. By providing the air guide plate 22 in this manner, not only can the gas discharged from the air blower 21 be directly applied to the sheet roll R, but also the gas guided by the air guide plate 22 can be applied to the sheet roll R. Therefore, even if there is only one air blower 21, the gas can be applied to the sheet roll R from multiple directions.

[0020] In the inspection device 100 according to the present invention, the air blowing section 20 may include one or more air blowers 21, sensors 22 and 23, and an air blowing control device 25. The sensors include an entry sensor 23 that detects that the sheet roll R has entered the air blowing area of ​​the air blower 21, and a departure sensor 24 that detects that the sheet roll R has left the air blowing area. The air blowing control device 25 controls the air blower 21 so that the air blower 21 is driven when the entry sensor 23 detects that the sheet roll R has entered the air blowing area, and the air blowing control device 25 stops the air blower 21 when the departure sensor 24 detects that the sheet roll R has left the air blowing area. For example, when the sheet roll R is a toilet roll, the air blower 21 is driven only when the toilet roll passes through the air blowing area, thereby preventing paper dust generated from the toilet roll from scattering. Furthermore, when multiple air blowing zones for the sheet roll R are provided, if the blower 21 is constantly driven in all the air blowing zones, there is a concern that the air currents generated in each air blowing zone may interfere with each other. In this regard, by turning the blower 21 on and off as needed in each air blowing zone as in the above configuration, such air current interference can be suppressed.

[0021] A second aspect of the present invention relates to a method for manufacturing a sheet roll R. The manufacturing method according to the second aspect includes a step of inspecting the sheet roll R using the inspection device 100 according to the first aspect described above. More specifically, in the manufacturing method for the sheet roll R, first, a sheet roll R is obtained in which the base of the tail end T of the wound sheet is bonded to the outer circumferential surface (obtaining step). Next, Gas is blown onto the sheet roll R from the half of the sheet roll where the tail end T is not provided (non-tail half) (air blowing process). Next, it is detected that the tail end T has separated from the outer circumferential surface and risen up while the base remains adhered to the outer circumferential surface as a result of the gas being blown (detection process). Effect of the Invention

[0022] According to the present invention, it is possible to detect defects occurring at the tail end portion of the sheet roll while it is still adhered to the outer peripheral surface of the sheet roll. [Brief description of the drawings]

[0023] [Figure 1] FIG. 1 is a perspective view that illustrates a schematic configuration example of an inspection device. [Diagram 2] FIG. 2 is a plan view showing a process of blowing gas onto a sheet roll. [Diagram 3] FIG. 3 shows an example of a defect that occurred at the tail end of a sheet roll. [Figure 4] FIG. 4 shows an example of a camera included in the detection unit. [Diagram 5] Figure 5(a) shows a sequence of images captured by the planar camera, Figure 5(b) shows a sequence of images captured by the side camera, and Figure 5(c) shows an example of a defect in the tail end captured by the side camera. [Figure 6] FIG. 6 shows an example of an optical sensor included in the detection unit. [Figure 7] FIG. 7 shows the state of the tail end that is determined to be normal in the inspection using the optical sensor. [Figure 8] FIG. 8 is a plan view showing a process of blowing gas onto a sheet roll by a plurality of blowers. [Figure 9] FIG. 9 is a plan view showing a process of blowing gas onto the sheet roll using an air guide plate. [Figure 10] FIG. 10 shows an example of controlling the blowing of air into a blowing area using an entry sensor and an exit sensor. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0024] Hereinafter, the embodiments of the present invention will be described with reference to the drawings. The present invention is not limited to the embodiments described below, and includes appropriate modifications of the embodiments described below within the scope obvious to those skilled in the art.

[0025] FIG. 1 is a schematic diagram of an inspection device 100 according to an embodiment of the present invention. As shown in FIG. 1, the inspection device 100 according to the present invention is used for the purpose of inspecting a cylindrical sheet roll R in which a long sheet is wound in multiple layers. In this embodiment, it is assumed that the sheet roll R is a toilet roll to be inspected. The sheet roll R has an adhesive applied near the tip of its outermost layer, and the tail end T is formed by attaching the adhesive applied portion to the outer peripheral surface of the sheet roll R. The tail end T is fixed to the outer peripheral surface of the sheet roll R at an adhesive portion G near the base, and a portion closer to the tip than the adhesive portion G becomes a gripping portion. For example, when a consumer starts using the sheet roll R, the consumer can unwind the sheet from the sheet roll R by pinching the gripping portion of the tail end T with his / her fingers and peeling off the adhesive portion G. The appropriate width of the gripping portion of the tail end T is about 10 to 50 mm, and there is no problem even if there is a difference between individual pieces within that range. Such a sheet roll R, specifically a toilet roll, may be manufactured by a known method.

[0026] As shown in FIG. 1, the inspection device 100 includes a conveying unit 10 for conveying a sheet roll R. The sheet roll R is conveyed in a fixed direction toward the downstream side of the device by the conveying unit 10. At this time, the conveying unit 10 can continuously convey a plurality of sheet rolls R at a predetermined interval. A known conveying device can be used as the conveying unit 10. In this embodiment, the conveying unit 10 includes a belt conveyor 11 and left and right side walls 12. The belt conveyor 11 includes an endless belt stretched over a driving pulley (not shown) and a driven pulley (not shown), and the conveying surface of the sheet roll R is formed by this endless belt. Note that the conveying unit 10 is not limited to a belt conveyor, and a roller conveyor, a chain conveyor, or the like can also be used, or these can be used in combination. The side walls 12 are formed on both the left and right sides of the width direction of the belt conveyor 11 along the conveying direction, and prevent the sheet roll R from falling off the conveying surface of the belt conveyor 11. As described later, in this embodiment, it is necessary to blow gas onto the sheet roll R being transported by the belt conveyor 11. For this reason, it is preferable that the side walls 12 are kept at a height that does not obstruct this airflow. Specifically, the height of the side walls 12 should be 5 to 15% of the axial length of the sheet roll R. For example, since the axial length of a typical toilet roll (i.e., the sheet width) is about 100 to 115 mm, it is appropriate that the height of the side walls 12 be 5 to 17 mm.

[0027] In this embodiment, the sheet roll R is transported with its end face in contact with the transport surface of the belt conveyor 11. By keeping the sheet roll R in an upright state in this manner, the sheet roll R can be transported stably by the belt conveyor 11.

[0028] As shown in Fig. 1, the inspection device 100 includes an air blowing section 20 for blowing gas against the sheet roll R being conveyed. The air blowing section 20 includes at least one air blower 21. The air blower 21 may be a known one. For example, the air blower 21 may be a circulator that generates an air flow by rotating a fan, a blower that compresses the air flow generated by the rotation of the fan through a nozzle and discharges it, or an air blow gun that includes a compressor that compresses air and a nozzle that discharges the compressed air.

[0029] 2(a) shows the sheet roll R from a plan view onto which gas is being blown by the blower 20. As shown in these Figs. 1 and 2(a), by blowing gas from the blower 21 onto the sheet roll R, the tail end T of the sheet roll R is fanned by the gas and stands up from the outer circumferential surface. That is, in the example shown in Fig. 2(a), the sheet roll R is wound with a sheet clockwise in a plan view, and a bonding part G is formed at the base of the tail end T. For such a sheet roll R, the blower 21 is disposed so as to blow gas onto the half of the sheet roll R that does not have the tail end T (i.e., the non-tail half R1).

[0030] The non-tail half R1 will be described in more detail with reference to Fig. 2(b). As shown in Fig. 2(b), when the sheet roll R is viewed in plan from the end face side, a virtual first straight line L1 is drawn connecting the center of the sheet roll R and the adhesive part G. A virtual second straight line L2 is also drawn perpendicular to the first straight line L1. The half of the sheet roll R where the adhesive part G is not provided, with the second straight line L2 as the boundary, is referred to as the non-tail half R1. On the other hand, the half of the sheet roll R where the adhesive part G is provided, with the second straight line L2 as the boundary, is referred to as the tail half R2.

[0031] FIG. 2(c) is a schematic diagram showing the flow of the gas blown from the blower 20 to the sheet roll R. As shown in FIG. 2(c), the gas discharged from the blower 20 hits the non-tail half R1 of the sheet roll R, and then flows toward the tail half R2. In FIG. 2(c), the linear direction of travel of the gas discharged from the blower 20 is indicated by a straight line indicated by the symbol W. In FIG. 2(c), the angle (acute angle side) between the gas travel direction W and the second straight line L2 of the sheet roll R described above is indicated by the symbol θ. In this case, the angle θ is most preferably 90 degrees, but may be in the range of 45 to 90 degrees. In particular, the angle θ is preferably 50 to 90 degrees, more preferably 55 to 90 degrees, and particularly preferably 60 to 90 degrees. In this way, the blower 20 blows gas to the sheet roll R from the non-tail half R1 side. As a result, if the tail end T of the sheet roll R is normal, it will be separated from the outer peripheral surface by the air flow and rise up while its base (bonded part G) remains bonded to the outer peripheral surface of the sheet roll R. In particular, since the gas discharged from the blowing unit 20 hits the non-tail half R1 of the sheet roll R and then goes around to the back side and escapes, the tail end T will maintain a state of being separated from the outer peripheral surface of the sheet roll R and rising up with the bonded part G as a fulcrum while it is receiving air from the blowing unit 20.

[0032] In addition, in the state where the sheet roll R is being transported by the belt conveyor 11, the orientation of the tail end T of the sheet roll R can be aligned to a certain degree. Specifically, before the sheet roll R is individually cut, a number of sheet rolls R called logs are connected in the axial direction. In particular, in the log state, the orientation of the portion that will become the tail end T of each sheet roll R is aligned. Then, by cutting this log to a predetermined width, individual sheet rolls R are obtained. After cutting the log in this way, the individual sheet rolls R are made to stand upright and then introduced into the inspection device 100 according to this embodiment, and at that time, the multiple sheet rolls R formed from one log basically follow the same transport path. Therefore, the orientation of the tail end T of each sheet roll R does not deviate significantly between the time when the log is cut and the time when the sheet rolls are introduced into the inspection device 100, and the tail end T is introduced into the inspection device 100 with the orientation of the tail end T being approximately aligned. In this way, the multiple sheet rolls R produced from one log are transported by the belt conveyor 11 with the orientation of the tail end T being approximately aligned. Therefore, by adjusting the orientation of the part that will become the tail end T in the log state, it is possible to inspect almost all of the sheet rolls R by installing at least one blower 21 in the transport process.

[0033] In the example shown in FIG. 2, the tail end T of the sheet roll R on the belt conveyor 11 faces almost toward the right side wall of the belt conveyor 11, so the blower 21 may be arranged on the left side wall of the belt conveyor 11 and configured to blow gas from the left side wall of the belt conveyor 11 toward the right side wall of the belt conveyor 11 almost directly across. Note that the illustrated example is only an example, and the arrangement of the blower 21 and the gas discharge direction can be appropriately adjusted according to the direction of the tail end T of the sheet roll R on the belt conveyor 11. In addition, when a sheet roll R is found whose tail end T is not properly oriented with respect to the blowing direction of the blower 21 at the time of being placed on the belt conveyor 11, the orientation of the sheet roll R may be adjusted manually. In addition, a machine for properly aligning the orientation of the sheet roll R may be introduced to automatically align the orientation of the sheet roll R.

[0034] FIG. 3 shows an example of the movement when the defective tail end T is exposed to air. The defects shown in FIG. 3 are just an example. For example, in the example shown in FIG. 3(a), the adhesive part G is formed near the tip of the sheet roll R, and the tail end T is not formed or the gripping margin of the tail end T is extremely narrow. Such a sheet roll R is treated as a defective product having a defective tail end T because it is difficult for consumers to peel off the adhesive part G. In this case, even if air is applied to the non-tail half R1 side of the sheet roll R, the tail end T does not rise. Also, in the example shown in FIG. 3(b), the adhesive part G is not formed on the outer peripheral surface of the sheet roll R, and as a result, there is no part corresponding to the tail end T. Such a sheet roll R is also treated as a defective product. In this case, when gas is applied to the tail end T of the sheet roll R from its non-tail half R1 side, the leading edge of the sheet may rise up nicely while the gas is being blown, but since there is no adhesive portion G to serve as a fulcrum, once the gas blowing stops, the leading edge of the sheet will eventually detach from the outer peripheral surface of the sheet roll R and become elongated.

[0035] The inspection device 100 according to this embodiment distinguishes between a normal tail end T and a defective tail end T by utilizing the difference between the behavior of the normal tail end T when air is blown onto it and the behavior of the defective tail end T when air is blown onto it. Specifically, the inspection device 100 includes a detection unit 30 for detecting that the tail end T has risen while the adhesive portion G remains attached to the outer circumferential surface due to the blowing of air.

[0036] First, with reference to Fig. 4 and Fig. 5, an embodiment in which a digital camera equipped with an image sensor is used as the detection unit 30 will be described. In the embodiment shown in Fig. 4, the detection unit 30 includes a planar camera 31, a side camera 32, and a control device 33. The arrangement of the planar camera 31 and the side camera 32 is also shown in Fig. 1.

[0037] The planar camera 31 is for capturing an image of the sheet roll R onto which gas is blown during transport from a planar direction, and is installed directly above the transport path of the sheet roll R. The side camera 32 is for capturing an image of the sheet roll R onto which gas is blown from a side direction during transport, and is installed to the side of the transport path of the sheet roll R. These digital cameras are composed of, for example, a lens, a mechanical shutter, a shutter driver, a photoelectric conversion element such as a CCD image sensor unit or a CMOS image sensor unit, a digital signal processor (DSP) that reads the charge amount from the photoelectric conversion element and generates image data, an IC memory, and the like. The images (including still images and videos) captured by each of the cameras 31 and 32 are transmitted to the control device 33 via wire or wirelessly.

[0038] The control device 33 analyzes the images acquired by the cameras 31 and 32, and judges whether there is a defect in the sheet roll R, particularly a defect in the tail end T, that is captured in the images. Such a control device 33 can be realized by a computer in which a predetermined control program is installed. The computer constituting the control device 33 includes a control calculation unit, a storage unit, an input unit, and an output unit. The control calculation unit is composed of, for example, a processor and a memory. Examples of the processor are known CPUs and GPUs. The processor performs predetermined calculation processing and image processing according to the programs and data stored in the memory, and executes various control processing while writing the results of the processing in the working space of the memory. The memory is composed of, for example, a volatile memory such as a RAM (Random Access Memory), and is used for the calculation processing by the processor. The storage unit is an element for storing data that is mainly used for processing in the control calculation unit. In addition, the storage unit may store a program used for processing in the processor. In addition, the storage unit may store image data acquired by each of the cameras 31 and 32. The storage unit is composed of a non-volatile memory such as a ROM (Read Only Memory) or a flash memory, and an HDD (Hard Disk Drive). The input unit includes an input interface for receiving image data from each of the cameras 31 and 32. The input unit may also include known input devices such as a keyboard, a mouse, or a touch panel. The output unit includes an output interface for outputting to the outside the results of the arithmetic processing by the control and arithmetic unit and the control commands generated by the control and arithmetic unit. The output unit may also include a known display device such as a liquid crystal display or an organic EL display, and a speaker device for outputting sound.

[0039] FIG. 5(a) shows an example of a continuous image captured by the flat camera 31. As described above, when the tail end T of the sheet roll R is normal, when the blower 21 blows gas onto it, the tail end T rises with the adhesive part G as a fulcrum, and maintains that state for a certain period of time. Therefore, the tail end T performing such a series of operations is captured in the continuous images captured by the flat camera 31. The control device 33 analyzes the continuous images captured by the flat camera 31 and determines that the sheet roll R for which the tail end T has been identified as being properly raised is normal. In particular, before the gas is blown onto it, the tail end T is often attached to the outer peripheral surface of the sheet roll R or there is almost no gap between the two, so that it is difficult to accurately determine whether the tail end T is properly formed even if the flat image of the sheet roll R before the gas is blown onto it is analyzed. On the other hand, as shown in Figure 5 (a), by blowing gas onto the sheet roll R to raise the tail end T, the presence of the tail end T becomes prominent in the captured image, and therefore it is possible to more accurately determine whether the tail end T is properly formed by image analysis.

[0040] The image analysis method is not particularly limited, and a known algorithm used to detect a specific object (here, the tail end T) from an image may be adopted. Examples of object detection algorithms include Haar-like feature classification and HOG (Histogram of Oriented Gradients). Object detection can also be performed using machine learning technology. Examples of object detection algorithms using machine learning include R-CNN (Regions with Convolutional Neural Network) and YOLO (You Only Look Once). Images captured by the planar camera 31 and the side camera 32 may be used as training data for machine learning. In this case, the images captured by each of the cameras 31 and 32 are stored in a storage unit and associated with a correct answer label related to whether or not the tail end T has risen. Then, a pair of the captured image and the correct answer label can be used as training data for machine learning to generate a trained model for determining whether the tail end T has risen.

[0041] FIG. 5(b) shows an example of a continuous image captured by the side camera 32. As in FIG. 5(a), when the tail end T of the sheet roll R is normal, when the blower 21 blows gas onto the tail end T, the tail end T rises with the adhesive part G as a fulcrum, and the state is maintained for a certain period of time. Such movement of the tail end T can be confirmed from the continuous images captured by the side camera 32. For this reason, the control device 33 analyzes the continuous images captured by the side camera 32 and determines that the sheet roll R for which the appropriate rising movement of the tail end T can be identified is normal. Depending on the position of the side camera 32, the tail end T may not appear in the captured image, and the movement of the tail end T may not be confirmed. In such a case, if the normal movement of the tail end T can be confirmed from the image captured by the above-mentioned flat camera 31, the sheet roll R may be determined to be normal. In other words, if the normal movement of the tail end T can be confirmed from even one of the multiple cameras, the sheet roll R can be determined to be normal.

[0042] In addition, according to the image from the side camera 32, the tail end T can be captured as a surface. For example, as shown in FIG. 3(c), even if the tail end T moves normally due to the blowing of gas, there are cases where defects such as chipping, tears, and breakage occur on the surface of the tail end T. By analyzing the image captured by the side camera 32, it is possible to detect such defects on the surface of the tail end T. In particular, before the gas is blown onto the sheet roll R, the tail end T overlaps with the outer peripheral surface of the sheet roll R, so that even if the above-mentioned defects occur on the surface of the tail end T, the defective portion may not be accurately detected by analyzing the color and shape of the tail end T in the captured image. On the other hand, after the gas is blown onto the sheet roll R, the tail end T rolls up, so that the shape of the defective portion can be easily identified in the captured image. For this reason, in order to detect defects on the surface of the tail end T, it is effective to analyze the captured image of the side camera 32.

[0043] Also, as shown in FIG. 5, in order to identify the movement of the tail end T by image analysis, it is necessary to maintain the movement of the tail end T at a level that can be captured by the planar camera 31 and the side camera 32. The movement speed of the tail end T can be controlled by the strength of the wind blowing against the sheet roll R. For example, assuming that digital cameras with a frame rate of 30 fps are used as each of the cameras 31 and 32, the strength of the wind blowing against the sheet roll R is preferably a Reynolds number of 39,000 to 60,000, more preferably 40,000 to 55,000, and even more preferably 42,000 to 50,000. The strength of the wind blowing against the sheet roll R is preferably a Reynolds number of 39,000 or more, more preferably 45,000 or more, and even more preferably 53,000 or more, with the toilet roll diameter (0.114 m) as the representative length, because it is necessary to quickly raise the tail end T from the outer peripheral surface of the sheet roll R. On the other hand, the upper limit of wind strength is the wind speed at which the sheet roll being transported is not blown away and deviates from the transport path, but even if such problems do not occur, unnecessarily strong winds can stir up surrounding dust and other foreign matter, posing the risk of foreign matter adhering to products, and can also result in unnecessary consumption of electricity. From this viewpoint, the Reynolds number is preferably 110,000 or less, more preferably 90,000 or less, and even more preferably 75,000 or less. If the wind is weaker than this, it becomes difficult to raise the tail end T from the outer circumferential surface of the sheet roll R. Also, if the wind is too strong, the lightweight sheet roll R may be blown away and deviate from the conveying path, and power may be wasted. In particular, in this embodiment, it is preferable to adjust the strength of the wind blowing against the sheet roll R so that the airflow that hits the sheet roll R and flows to the back side of the sheet roll R becomes a laminar flow. "Laminar flow" means a flow that does not generate turbulence or vortex flow in a direction different from the gas discharge direction.

[0044] The Reynolds number is a parameter in fluid mechanics, and is a dimensionless quantity defined as the ratio of inertial force to viscous force. It quantifies the relative importance of these inertial and viscous forces in a flow. When the Reynolds number exceeds a certain value, the flow becomes turbulent, and when the Reynolds number is below a certain value, the flow becomes laminar. The Reynolds number is expressed by the following formula. [Formula]Re = (ρ × v × L) / μ Here, Re is the Reynolds number, ρ is the density of the fluid, v is the velocity of the fluid, L is the characteristic length that represents the flow characteristics, and μ is the viscosity of the fluid. For example, if we consider blowing air onto a toilet roll, ρ is the air density of 1.206 kg / m 3 , v is the wind speed (e.g., 3 m / s), L is the diameter of the sheet roll (e.g., 0.114 m), and μ is the air viscosity coefficient 1.83×10 -5 Just calculate in Pa·s.

[0045] The planar camera 31 and the side camera 32 are not limited to being provided at one location each, but may be provided at multiple locations along the conveying path of the belt conveyor 11. The digital cameras are not limited to the planar camera 31 and the side camera 32 described above, but instead of or in addition to these cameras 31 and 32, a camera (oblique camera) for photographing the sheet roll R to which gas is blown from obliquely above or below may be provided. If any one of the planar camera 31, the side camera 32, and the oblique camera (not shown) can photograph a state in which the tail end T is properly raised, the sheet roll R can be determined to be normal.

[0046] Next, an embodiment in which an optical sensor 33 is used as the detection unit 30 will be described with reference to Figs. 6 and 7. In the embodiment shown in Fig. 6, the detection unit 30 includes an optical sensor 33 and a control device 33. The optical sensor 33 is composed of a light projector 33a and a light receiver 33b. The light projector 33a and the light receiver 33b are each connected to the control device 33 and operate according to the control of the control device 33. The light projector 33a irradiates an inspection light 33c toward the light receiver 33b. The light receiver 33b receives the inspection light 33c, converts the optical energy of the received inspection light 33c into an electrical signal by the photoelectric effect, and outputs the electrical signal to the control device 33. In the example shown in FIG. 6, the receiver 33b is provided at a position facing the projector 33a. However, a reflector may be provided at a position facing the projector 33a, and the receiver 33b may be provided at a position adjacent to the projector 33a, so that the inspection light 33c reflected by the reflector is received by the receiver 33b.

[0047] As shown in FIG. 6, the light projector 33a and the light receiver 33b are arranged so that the inspection light 33c advances along the peripheral surface of the sheet roll R conveyed by the belt conveyor in the vicinity of the peripheral surface. Specifically, as shown in the plan view of FIG. 7, the inspection light 33c is irradiated at a position that is not in contact with the tail end T of the sheet roll R before the gas is blown. On the other hand, when the tail end T of the sheet roll R is properly raised with the adhesive part G as a fulcrum by the blowing of the gas, the irradiation position of the inspection light 33c is adjusted so that the tail end T in this raised state comes into contact with the inspection light 33c. When the tail end T comes into contact with the inspection light 33c, the inspection light 33c is blocked by the tail end T, so that the inspection light 33c does not reach the light receiver 33b or the light amount (light energy) of the inspection light 33c that reaches the light receiver 33b becomes weak. This causes a change in the electrical signal output from the light receiver 33b to the control device 33, so that the control device 33 can detect that the tail end T has come into contact with the inspection light 33c. When the tail end T comes into contact with the inspection light 33c by blowing gas in this way, the control device 33 can determine that the tail end T is normal. On the other hand, when the tail end T does not come into contact with the inspection light 33c even by blowing gas, the control device 33 can determine that there is an abnormality in the tail end T. Specifically, when the tail end T does not come into contact with the inspection light 33c, as shown in FIG. 3, it is suspected that there is a defect such as the adhesive portion G being inappropriately positioned and the gripping margin of the tail end T not being sufficiently formed.

[0048] As described above, the sheet roll R determined by the detection unit 30 to have defects mainly in the tail end T is likely to be a defective product, and therefore it is preferable to discharge the sheet roll R from the conveying path of the conveying unit 10. For example, the control device 33 included in the detection unit 30 may display a warning message on a display or the like to notify an operator monitoring the sheet roll R being conveyed that there is a sheet roll R determined to be a defective product. In this case, the operator can remove the defective product from the conveying path. Also, the defective sheet roll R can be mechanically discharged from the conveying path individually. The means for mechanically discharging the defective product is not particularly limited, and any known means may be used. For example, a mechanism for mechanically discharging the defective product by compressed air, a push rod, air suction, or the like is provided near the conveying path. Then, when the control device 33 detects a defective sheet roll R, it may drive this discharge mechanism to discharge the defective product individually outside the conveying path.

[0049] Next, with reference to FIG. 8, a case where a plurality of blowers 21 are arranged on the conveying path of the sheet roll R will be described. As shown in FIG. 8, a plurality of blowers 21(a)-(d) may be arranged along the conveying path of the belt conveyor 11. In particular, the plurality of blowers 21(a)-(d) may have different gas exhaust directions. In the illustrated example, four blowers 21(a)-(d) with different exhaust directions are arranged to blow gas onto the sheet roll R on the belt conveyor 11. The number of blowers 21 may be two, three, or five or more. However, since a large number of blowers 21 increases the cost of introduction and the power consumption, it is appropriate that the number of blowers 21 used for the inspection is about two to six.

[0050] Specifically, in the example shown in FIG. 8, when the conveying direction of the belt conveyor 11 is the forward direction, the first blower 21(a) and the second blower 21(b) are disposed on the left side of the belt conveyor 11, and the third blower 21(c) and the fourth blower 21(d) are disposed on the right side of the belt conveyor 11. In addition, the first blower 21(a) exhausts gas toward the right side (about 90 degrees) relative to the belt conveyor 11, and the second blower 21(b) exhausts gas toward the right side (about 90 degrees). In addition, the third blower 21(c) exhausts gas toward the right rear (about 45 degrees). In addition, the third blower 21(c) exhausts gas toward the left diagonal front (about 45 degrees), and the fourth blower 21(d) exhausts gas toward the left side (about 90 degrees). In this way, by arranging a plurality of blowers 21(a)-(d) with different gas discharge directions in sequence along the conveying path of the belt conveyor 11, even if the orientation of the tail end T of the sheet roll R on the belt conveyor 11 is not uniform, any of the blowers 21 can supply airflow to the sheet roll R to raise the tail end T. As described above, it is possible to align the orientation of the sheet roll R on the belt conveyor 11 to some extent, but if such adjustment is time-consuming, the configuration shown in Fig. 8 can be adopted. This can save the time and effort of adjusting the orientation of the sheet roll R and placing it on the belt conveyor 11.

[0051] Furthermore, when multiple blowers 21 are provided, it is preferable to provide one planar camera 31 (see FIG. 4) for each blower 21. If the orientation of the sheet rolls R on the belt conveyor 11 is not uniform, the tail end T of a normal sheet roll R will rise due to the gas from one of the blowers 21. By providing a planar camera 31 for each blower 21, the moment when the tail end T rises can be captured by one of the planar cameras 31. If the rising of the tail end T cannot be detected by any of the planar cameras 31, it can be determined that the tail end T of that sheet roll R is defective. Note that image data from each camera is sent to a control device for image analysis.

[0052] Next, referring to FIG. 9, a case where the air guide plate 22 is installed in the conveying path of the sheet roll R will be described. In the example shown in FIG. 9, the air blowing section 20 includes an air blower 21 and an air guide plate 22. The air blower 21 is provided on one of the left and right sides of the belt conveyor 11, and the air guide plate 22 is provided on the opposite side. The air blower 21 is provided, for example, on the left side of the belt conveyor 11, and discharges gas toward the right side (about 90 degrees) of the belt conveyor 11. On the other hand, the air guide plate 22 is provided, for example, on the right side of the belt conveyor 11. The air guide plate 22 is configured to reflect the gas discharged from the air blower 21 and reaching the right side beyond the belt conveyor 11, and form an air flow toward the belt conveyor 11 again. In addition, the whole or part of the air guide plate 22 may be inclined obliquely with respect to the conveying direction of the belt conveyor 11 in a plan view, to adjust the direction of the gas reflected by the air guide plate 22.

[0053] This makes it possible to raise the tail end T of the sheet roll R on the belt conveyor 11 by either the gas discharged directly from the blower 21 or the gas reflected by the air guide plate 22. Therefore, even if the orientation of the sheet roll R transported by the belt conveyor 11 is not uniform, the tail end T can be raised by the gas and the presence or absence of defects can be inspected. In addition, compared to the case where multiple blowers 21 are provided as in the embodiment shown in Figure 8, the introduction cost and maintenance cost of the air guide plate 22 are inexpensive, so it is possible to inspect the sheet roll R with an ununiform orientation with an inexpensive and simple configuration.

[0054] In the embodiment shown in Fig. 9, it is preferable to provide one planar camera 31 (see Fig. 4) in each of the areas where the gas is directly blown from the blower 21 and the area where the gas is reflected by the air guide plate 22. By providing a planar camera 31 in each area in this manner, the moment when the tail end T rises up can be captured by one of the planar cameras 31. If the rising of the tail end T cannot be detected by any of the planar cameras 31, it may be determined that the tail end T of that sheet roll R is defective.

[0055] Next, a case where the blower 21 is controlled to be turned on / off will be described with reference to Fig. 10. In the example shown in Fig. 10, the blower section 20 includes, in addition to the blower 21, an entrance sensor 23, a departure sensor 24, and an air blowing control device 25 that controls the blower 21 based on detection signals from these sensors 23, 24. The entrance sensor 23 detects the entrance of the sheet roll R into the blowing area by the blower 21, and the departure sensor 24 detects the departure of the sheet roll R outside the blowing area. The air blowing control device 25 can be realized by a computer, similar to the above-mentioned control device 33. Note that the air blowing control device 25 and the control device 33 may be configured by the same computer or different computers.

[0056] Specifically, the entrance sensor 23 and the departure sensor 24 can be sensors each having a light projector 23a, 24a and a light receiver 23b, 24b, respectively, similar to the above-mentioned optical sensor 33. The light projector 23a of the entrance sensor 23 irradiates the inspection light 23c, 24c along the conveying surface of the belt conveyor 11. When the sheet roll R conveyed by the belt conveyor 11 comes into contact with the inspection light 23c, the light intensity of the inspection light 23c reaching the light receiver 23b of the entrance sensor 23 weakens, and the change in the light intensity is transmitted to the air blowing control device 25 as an electric signal. As a result, the air blowing control device 25 determines that the sheet roll R has entered the air blowing area, and drives the air blower 21 to start blowing air to the sheet roll R on the conveying surface of the belt conveyor 11. On the other hand, the light projector 24a of the departure sensor 24 irradiates the inspection light 24c along the conveying surface of the belt conveyor 11. When the sheet roll R conveyed by the belt conveyor 11 comes into contact with the inspection light 24c, the amount of inspection light 24c that reaches the light receiver 24b of the detachment sensor 24 decreases, and the change in the amount of light is transmitted as an electrical signal to the air blowing control device 25. As a result, the air blowing control device 25 determines that the sheet roll R has detached outside the air blowing area, and stops the air blower 21. In this way, the air blower 21 can be driven only when the sheet roll R is within the air blowing area, which leads to a reduction in power consumption.

[0057] Also, a plurality of blowers 21 may be provided at intervals on the conveying path of the belt conveyor 11, and each blower 21 may blow air to the sheet roll R in turn. In this case, a plurality of blowing zones are formed on the conveying path of the belt conveyor 11. In such a case, it is preferable to provide a set of an entrance sensor 23 and a departure sensor 24 for each blowing zone, and to control the on / off of the blower 21 in each blowing zone. That is, for example, when a first blowing zone, a second blowing zone, and a third blowing zone are formed in order from the upstream side of the conveying path, the sheet roll R conveyed by the belt conveyor 11 passes through the blowing zones in this order. At this time, when the sheet roll R is in the first blowing zone, only the blower 21 provided in the first blowing zone is driven and the blowers 21 in the other blowing zones are stopped, and similarly, when the sheet roll R is in the second blowing zone, only the blower 21 provided in the second blowing zone is driven and the blowers 21 in the other blowing zones are stopped. By driving the blowers 21 in each blowing zone in turn in this manner, it is possible to prevent the air currents formed by the blowers 21 from interfering with each other.

[0058] In the above, in order to express the contents of the present invention, the present specification has described the embodiments of the present invention with reference to the drawings. However, the present invention is not limited to the above-mentioned embodiments, and includes modifications and improvements that are obvious to a person skilled in the art based on the matters described in the present specification. [Industrial Applicability]

[0059] The present invention relates to an inspection device for sheet rolls such as toilet rolls and a manufacturing method thereof. Therefore, the present invention can be suitably used in the manufacturing industry of toilet rolls and the like. [Explanation of symbols]

[0060] 10...Transportation section 11...Belt conveyor 12... Side wall 20... Blower section 21... Blower 22... Air guide plate 23... Entry sensor 24... Exit sensor 25... Air flow control device 30... Detection unit 31... Planar camera 32... Side camera 33...Control device 33...Optical sensor 33a...Light emitter 33b...Light receiver 33c...Inspection light 100...Inspection device R…Sheet roll R1…Non-tail half R2: Half tail T: Tail end G…Adhesive part

Claims

1. An inspection device for a sheet roll in which the base of a tail end of a wound sheet is bonded to an outer peripheral surface, comprising: a blower that blows gas onto the sheet roll from a half side of the sheet roll where the tail end is not provided; a detection unit for detecting that the tail end portion has separated from the outer circumferential surface and risen up while the base portion is adhered to the outer circumferential surface due to the gas being blown thereon; Inspection equipment.

2. The tail end is maintained in an upright state separated from the outer circumferential surface while the gas is blown by the blower. The detection unit detects the tail end in an upright state.

2. The inspection device according to claim 1.

3. A conveying unit that conveys the sheet roll is further provided, The blower blows the gas against the sheet roll when the sheet roll is in an upright state and is transported by the transport unit.

2. The inspection device according to claim 1.

4. the detection unit includes an optical sensor that emits inspection light, The optical sensor detects that the tail end portion separated from the outer circumferential surface has come into contact with the inspection light.

2. The inspection device according to claim 1.

5. The detection unit includes an image sensor, The image sensor captures an image of the sheet roll while the air is being blown by the blower.

2. The inspection device according to claim 1.

6. The image sensor captures an image of the end surface of the sheet roll.

6. The inspection apparatus according to claim 5.

7. The image sensor captures an image of the peripheral surface of the sheet roll.

6. The inspection apparatus according to claim 5.

8. A storage unit that stores an image captured by the image sensor, The captured image stored in the storage unit is stored in association with a correct answer label related to whether the tail end portion has risen or not, The pair of the captured image and the correct label is used as training data for generating trained data by machine learning to be used in the processing by the detection unit.

6. The inspection apparatus according to claim 5.

9. The blower unit includes a plurality of blowers.

2. The inspection device according to claim 1.

10. The blower section includes: One or more fans; a sensor for detecting when the rolled sheet enters an area where the air is blown by the air blower and when the rolled sheet leaves the area where the air is blown; and a blowing control device that drives the blower when the sensor detects the entry of the rolled sheet into the blowing area and stops the blower when the sensor detects the departure of the rolled sheet from the blowing area.

2. The inspection device according to claim 1.

11. The blower section includes: One or more fans; A wind guide plate is provided to guide the gas sent from the blower to the roll sheet.

2. The inspection device according to claim 1.

12. A method for manufacturing a sheet roll, comprising the steps of: obtaining a sheet roll in which the base of the tail end of the wound sheet is bonded to the outer peripheral surface; a blowing step of blowing gas onto the sheet roll from a half side of the sheet roll where the tail end is not provided; a detection step of detecting whether the tail end portion has separated from the outer circumferential surface and risen up while the base portion is adhered to the outer circumferential surface as a result of the gas being blown thereon. Manufacturing method.

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