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 100 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; and a detection unit 30 for detecting a tail end portion T of the sheet roll R. The blowing unit 20 includes a blowout unit 21 for blowing out a gas and a revolution unit 22 for revolving the blowout unit 21 around a fixed point while directing a blowout direction of the gas from the blowout unit 21 to the fixed point.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] A 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 circumferential 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 blowing unit 20 and a detection unit 30. The blowing unit 20 includes a blowing unit 21 and a revolving unit 22. The blowing unit 21 is a part that blows out gas. The blowing unit 21 is not limited to one, and two or more blowing units 21 may be provided. The revolving unit 22 revolves the blowing unit around a fixed point while keeping the blowing direction of the gas from the blowing unit 21 facing the fixed point. When there are multiple blowing units 21, the revolving unit 22 may revolve the multiple blowing units 21 simultaneously. The blowing unit 21 may be a blower that generates an air flow by itself, or may be an outlet of a nozzle that guides the air flow generated by the blower. Therefore, the revolving unit 22 may be one that revolves the blower itself, or one that revolves the outlet of a nozzle. The detection unit 30 is configured to detect the tail end T of the sheet roll R. Specifically, the detection unit 30 is configured to detect that the tail end T has risen up from the outer circumferential surface while the base is adhered to the outer circumferential surface due to the blowing of gas. Note that the blowing of gas to the sheet roll R and the inspection of the rising 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, the gas blowing part 21 is revolved by the revolving part 22, and the sheet roll R is introduced into the orbit of the blowing part 21, so that the rising of the tail end T of the sheet roll R can be inspected. In this way, by blowing gas onto the sheet roll R and inspecting the rising of the tail end T, various defects that have occurred in the tail end T can be detected. Specifically, if the tail end T rises properly by blowing gas onto the sheet roll R, the tail end T can be judged to be normal. On the other hand, if the tail end T does not rise even by blowing gas, it can be judged 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 part G) of the tail end T is peeled off from the outer circumferential surface of the sheet roll R by blowing gas, it can be judged that there is a defect such as adhesive not being applied properly to the tail end T. In particular, by revolving the gas blowing portion 21, the tail end T of the sheet roll R can be made to stand up by blowing gas from the blowing portion 21 regardless of the orientation of the tail end T.

[0011] 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 blowing unit 20 is preferably configured to blow gas onto the sheet roll R when the sheet roll R is conveyed by the conveying unit 10 in an upright state. In particular, the revolving unit 22 preferably revolves the blowing unit 21 so as to blow gas onto the entire circumference of the sheet roll R during the period from when the sheet roll R conveyed by the conveying unit 10 enters the gas blowing area by the blowing unit 20 until it leaves the blowing area. For example, when there is one blowing unit 21, the revolving unit 22 may make this one blowing unit 21 make at least one revolution around the sheet roll R. Also, when there are multiple blowing units 21 (two or more), the revolving unit 22 may revolve the multiple blowing units 21 so that the multiple blowing units 21 blow gas onto the entire circumference of the sheet roll R. By blowing gas onto the sheet roll R while it is being transported by the transport 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. Furthermore, by revolving the blowing unit 21 so as to blow gas onto the entire circumference of the sheet roll R, the tail end T can be made to stand up by blowing gas from the blowing unit 21, regardless of the orientation of the tail end T of the sheet roll R.

[0012] 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.

[0013] 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.

[0014] 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.

[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 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.

[0016] 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.

[0017] In the inspection device 100 according to the present invention, the blowing unit 20 may include one or more blowing units 21, sensors 23, 24, and a blowing control device 25. The sensors include an entry sensor 23 that detects that the sheet roll R has entered the blowing area by the blowing unit 21, and a departure sensor 24 that detects that the sheet roll R has left the blowing area. The blowing control device 25 starts blowing gas from the blowing unit 21 when the entry sensor 23 detects that the sheet roll R has entered the blowing area, and stops blowing gas from the blowing unit 21 when the departure sensor 24 detects that the sheet roll R has left the blowing area. For example, if the sheet roll R is a toilet roll, the blowing unit 21 is configured to blow gas only when the toilet roll passes through the 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 gas is constantly blown out from the blowing section 21 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 on / off the blowing of gas from the blowing section 21 as necessary in each air blowing zone as in the above configuration, such interference of air currents can be suppressed.

[0018] 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. Specifically, in the manufacturing method for the sheet roll R, 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 (blowing step). Next, the tail end of the sheet roll is detected (detecting step). Here, in the blowing step, the blowing part 21 revolves around a fixed point while the blowing direction from the gas blowing part 21 is kept facing the fixed point. Effect of the Invention

[0019] According to the present invention, it is possible to detect defects occurring in 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]

[0020] [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 (blowing units). [Figure 9] FIG. 9 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

[0021] 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.

[0022] 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.

[0023] 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.

[0024] 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.

[0025] 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.

[0026] The blower 20 also includes a revolving device 22 that revolves the blower 21 around the sheet roll R on the conveying surface. That is, the revolving device 22 is configured to revolve the blower 21 around a fixed point on the conveying surface while keeping the blowing direction of the blower 21 facing the fixed point. The fixed point can also be said to be the center of the orbit of the blower 21. Therefore, when the sheet roll R passes near the fixed point, the blower 21 blows gas onto the entire peripheral surface of the sheet roll R. In this embodiment, the revolving device 22 has a rotating part 22a that rotates in a plane parallel to the conveying surface, and a supporting part 22b that connects the rotating part 22a and the blower 21. The rotating part 22a rotates in a fixed direction by a known means such as a motor. The supporting part 22b connects the rotating part 22a and the blower 21 to each other so as to rotate the blower 21 together with the rotating part 22a.

[0027] As shown in FIG. 1, in this embodiment, the blower 21 revolves around the sheet roll R while blowing gas onto the sheet roll R. At this time, if the interval between the sheet rolls R on the conveying surface of the belt conveyor 11 is narrow, the blower 21 may collide with the sheet roll R. For this reason, the interval between the sheet rolls R needs to be wide enough to allow the blower 21 to pass through. In addition, if the conveying speed of the sheet roll R by the belt conveyor 11 is too fast or the rotation speed of the blower 21 by the revolving device 22 is too slow, the blower 21 may not be able to blow gas around the entire circumference of the sheet roll R while the sheet roll R passes through the orbit of the blower 21. For this reason, it is preferable to adjust the conveying speed of the belt conveyor 11 and the rotation speed of the revolving device 22 so that the blower 21 can make at least one revolution around the sheet roll R while the sheet roll R passes through the orbit of the blower 21. Also, when the sheet roll R enters the orbit of the blower 21, the belt conveyor 11 may be stopped once, and the conveyance of the sheet roll R by the belt conveyor 11 may be resumed after the blower 21 has made one revolution around the sheet roll R. In this way, by making the blower 21 revolve, gas can be efficiently blown around the entire circumference of the sheet roll R even by a single blower 21.

[0028] 2(a) shows the sheet roll R on which the gas is blown by the blower 20 in a plan view. As shown in these FIGS. 1 and 2(a), the sheet roll R is blown with gas from the blower 21, so that the tail end T of the sheet roll R is stirred up by the gas and sways. 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. When the blower 21 moves to a position where it can blow gas to the sheet roll R from the opposite side of the extension direction of the tail end T, the tail end T of the sheet roll R is raised by the gas discharged from the blower 21. More specifically, in the example shown in FIG. 2, when the conveying direction is forward, the sheet roll R is placed on the conveying surface of the belt conveyor 11 so that the extension direction of the tail end T faces diagonally backward to the right. Then, when the blower 21 is moved to the rear of the sheet roll R by the revolving device 22, it starts to blow gas forward onto the sheet roll R. At this time, gas is blown into the inner surface side of the tail end T of the sheet roll R, i.e., between the tail end T and the outer circumferential surface. As a result, the tail end T of the sheet roll R oscillates so as to be rolled up from the outer circumferential surface.

[0029] Also, FIG. 2(b) shows the change in the state of the tail end T to which the gas is applied in a continuous photographic manner. In particular, FIG. 2(b) shows the movement of the tail end T in a normal state. As shown in FIG. 2(b), when the tail end T is normal, when gas is blown from the opposite side of the stretching direction of the tail end T, the tail end T first moves away from the outer peripheral surface of the sheet roll R, and the distance between the tail end T and the outer peripheral surface gradually increases. At this time, since the tail end T remains attached to the outer peripheral surface at the bonding part G, the tip of the tail end T on the opposite side to the bonding part G rises up with the bonding part G as a fulcrum. After that, the tail end T rises up so as to be almost upright with respect to the outer peripheral surface of the sheet roll R, with the bonding part G as a fulcrum. At this time, the tip of the tail end T is the most distant from the outer peripheral surface of the sheet roll R. Then, the tail end T falls down in the opposite direction to the initial state, with the bonding part G as a fulcrum. The direction of the tail end T at this time is the opposite direction to the winding direction of the sheet roll R. That is, in the case of a sheet roll R in which the sheet is wound clockwise, the tail end T will eventually fall in a counterclockwise direction. In this state, the tail end T becomes stable, and the orientation of the tail end T will be maintained unless it is exposed to wind from another fan, for example.

[0030] 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. For this reason, it is also possible to adjust the orientation of the portion that will become the tail end T in the log state. However, in this embodiment, as described above, it is possible to blow gas onto the entire peripheral surface of one sheet roll R by the blower 21, so it is not necessarily necessary to align the orientation of the tail end T of the sheet roll R on the conveyance surface.

[0031] FIG. 3 shows an example of the movement when air is blown on a defective tail end T. The defect shown in FIG. 3 is only 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 blown on the tail end T of the sheet roll R from the opposite side of the stretching direction, the tail end T does not rise up. In addition, 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 air is blown on the tail end T of the sheet roll R from the opposite side of the stretching direction, the adhesive part G that serves as a fulcrum does not exist, so the tip of the sheet does not rise up well, and the tip side of the sheet is separated from the outer peripheral surface of the sheet roll R and stretched out.

[0032] 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.

[0033] 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.

[0034] 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.

[0035] 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.

[0036] 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 the tail end T, the tail end T stands up with the adhesive portion G as a fulcrum, and then moves to fall to the opposite side. Therefore, the tail end T performing such a series of actions 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 standing up is normal. In particular, in the state before the gas is blown, the tail end T is often attached to the outer circumferential 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 is analyzed. On the other hand, as shown in FIG. 5(a), by blowing gas onto the sheet roll R to make the tail end T stand up, the presence of the tail end T appears prominently in the captured image, so that it is possible to more accurately determine whether the tail end T is properly formed by image analysis.

[0037] 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.

[0038] FIG. 5(b) shows an example of a series of images 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 stands up with the adhesive part G as a fulcrum and then moves to fall to the opposite side. Such a movement of the tail end T can be confirmed from the series of images captured by the side camera 32. For this reason, the control device 33 analyzes the series of images captured by the side camera 32 and determines that the sheet roll R for which the tail end T has been identified as having an appropriate standing up movement 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.

[0039] 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.

[0040] Also, as shown in FIG. 5, in order to identify the movement of the tail end T by image analysis, it is necessary to suppress the movement speed of the tail end T to 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 3500 to 55000, more preferably 7500 to 40000, and even more preferably 20000 to 40000, with the diameter of the toilet roll (0.114 m) as the representative length. If the wind is weaker than this, the tail end T cannot be made to stand up from the outer peripheral surface of the sheet roll R, and if the wind is stronger than this, the movement of the tail end T exposed to the wind is too fast, making it difficult for each of the cameras 31 and 32 to always capture the moment when the tail end T stands up. Furthermore, if the wind is too strong, there is a risk that the lightweight sheet roll R will be blown away and deviate from the transport path, resulting in unnecessary consumption of electricity.

[0041] 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.

[0042] 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.

[0043] 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.

[0044] 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 position of the adhesive part G being inappropriate and the gripping margin of the tail end T not being sufficiently formed, or the adhesive part G not being formed on the sheet roll R and the tail end T not rising up properly.

[0045] 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.

[0046] Next, referring to FIG. 8, a case where a plurality of blowers 21 are provided in the blower section 20 will be described. As shown in FIG. 8, the blower section 20 may be configured to revolve two or more blowers 21(a, b) by one revolution device 22. That is, the first blower 21(a) and the second blower 21(b) are connected to one rotating section 22a of the revolution device 22 via a support section 22b. When the rotating section 22a rotates, these two blowers 21(a, b) rotate together. For example, in a 360-degree orbit, it is preferable to provide blowers 21(a, b) every 180 degrees, and to make the blowing directions of the two blowers 21(a, b) face each other. As a result, when the rotating section 22a rotates half a turn (180 degrees), it becomes possible for the two blowers 21(a, b) to blow gas against the entire circumference (360 degrees) of the sheet roll R. The number of blowers 21 provided for one revolving device 22 is not limited to two, and may be three or four. However, if the number of blowers 21 is large, the possibility of the blowers 21 colliding with the sheet roll R during rotation increases, so the number of blowers 21 is preferably two.

[0047] Next, a case of controlling the on / off of the blower 21 will be described with reference to Fig. 9. In the example shown in Fig. 9, the blower section 20 includes, in addition to the blower 21 and the revolving device 22, 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.

[0048] 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 blower 21 and the revolution device 22 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 transported 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 weakens, 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 and the revolving device 22. 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.

[0049] Also, a plurality of blowing sections 20 (blowers 21, revolving devices 22) may be provided at intervals on the conveying path of the belt conveyor 11, and each blowing section 20 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 blowing section 20 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 blowing section 20 provided in the first blowing zone is driven and the blowing sections 20 in the other blowing zones are stopped, and similarly, when the sheet roll R is in the second blowing zone, only the blowing section 20 provided in the second blowing zone is driven and the blowing sections 20 in the other blowing zones are stopped. By driving the blowing sections 20 in each blowing zone in sequence in this manner, it is possible to prevent the air currents formed by the blowing sections 20 from interfering with each other.

[0050] 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]

[0051] 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]

[0052] 10...Transportation section 11...Belt conveyor 12... Side wall 20... Blower section 21... Blower (blowout section) 22... Revolution device 22a...rotating portion a 22b...support portion 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 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; a detection unit for detecting the tail end of the sheet roll, The blower section includes: A blowing section that blows out the gas; a revolving part that revolves the blowing part around a fixed point while directing the blowing direction of the gas from the blowing part toward the fixed point, Inspection equipment.

2. A conveying unit that conveys the sheet roll is further provided, The revolving unit revolves the blowing unit so as to blow gas onto an entire circumference of the sheet roll during a period from when the sheet roll being transported by the transport unit enters a blowing area of ​​the gas by the blowing unit until when the sheet roll leaves the blowing area.

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 peeled off from the outermost layer comes 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 section includes: a sensor for detecting when the rolled sheet enters an air blowing area of ​​the air blowing unit and when the rolled sheet leaves the air blowing area; and a blowing control device that starts blowing gas from the blowing section when the sensor detects the entry of the rolled sheet into the blowing area, and stops blowing gas from the blowing section when the sensor detects the departure of the rolled sheet from the blowing area.

2. The inspection device according to claim 1.

10. 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; detecting the tail end of the sheet roll; In the blowing step, While the blowing direction of the gas from the blowing part is directed to a fixed point, the blowing part is revolved around the fixed point. Manufacturing method.

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