JP6049663B2 - Method for manufacturing an absorbent article - Google Patents

Description

  The present invention relates to a method for manufacturing an absorbent article, which includes at least an outline inspection step for inspecting the outline of an absorbent body of the absorbent article.

  Conventionally, in order to improve the quality of absorbent articles, in the process of manufacturing absorbent articles such as disposable diapers and sanitary napkins, the shape of semi-finished products and final products of absorbent articles, patterns printed on these, etc. Inspection of the position of the is carried out.

  For example, in Patent Document 1, a long continuous member used for an absorbent article is photographed for each predetermined photographing range using a camera (imaging device) while being transported, and the photographed image is displayed. Based on this, a method for manufacturing an absorbent article is disclosed in which an absorbent article having a pattern provided at a predetermined position is obtained by controlling the feeding speed of a continuous member.

JP 2007-61440 A

  By the way, considering the inspection of the outer shape of the absorber during the manufacture of the absorbent article using the camera as in the invention disclosed in Patent Document 1, the outer shape of the absorber is not a simple rectangle for various reasons. There may be no. For example, when worn, an absorbent body that extends from the wearer's stomach side to the back side through the crotch part has a shorter dimension in the short direction of the absorbent body because of the footstep in the portion covering the crotch part of the wearer. There may be. In other words, the absorbent body may include a portion in which the dimension in the short direction perpendicular to the longitudinal direction of the absorbent body varies along the longitudinal direction.

  Depending on the shooting environment with the camera, the part where the dimensions change is not a simple shape such as a rectangle, so when shooting the absorber using the camera, the shooting area should be properly illuminated. In some cases, the outer shape of the absorber cannot be accurately photographed. As a result, the manufactured absorbent article may not be determined to have an unacceptable outer shape in the inspection process even when an absorbent body whose outer shape is not acceptable is included. As a result, there is a possibility that an absorbent article including an absorbent body that may not be able to sufficiently exhibit the expected performance will be shipped.

  Therefore, an object of the present invention is to more accurately photograph the outer shape of the absorber including the portion in which the dimension in the short direction perpendicular to the longitudinal direction as described above changes along the longitudinal direction. It is an object of the present invention to provide a method for manufacturing an absorbent article, which can accurately determine whether or not it is acceptable.

In order to achieve the above object, the present invention provides:
A method of manufacturing an absorbent article using an absorbent body having a longitudinal direction and including a portion in which a dimension in a short direction perpendicular to the longitudinal direction varies along the longitudinal direction,
In the method for manufacturing the absorbent article, each of the absorbers can be obtained by photographing the absorber continuously conveyed in the longitudinal direction on a conveyance path with a plurality of lights while photographing with a single camera. Including an outer shape inspection process for inspecting the outer shape of
The outline inspection process includes
A camera placement step of placing the one camera above the transport path at a distance that allows the entire length of the absorber to be copied in the short direction;
An illumination arrangement step of arranging the plurality of illuminations on the upstream side and the downstream side in the conveying direction of the absorber, rather than the one camera,
Using the one camera, photographing each of the absorbers, and obtaining a whole image of each absorber,
An outer shape determination step for determining whether or not the outer shape of each absorber is acceptable from the image acquired in the photographing step;
Including at least
A method of manufacturing an absorbent article is provided.

  According to the present invention, it is possible to more appropriately illuminate the contour of the absorber by arranging the plurality of illuminations on the upstream side and the downstream side in the conveying direction of the absorber, rather than one camera. Therefore, the outer shape of the absorber can be inspected more accurately. As a result, it is possible to manufacture an absorbent article including an absorber that can sufficiently exhibit the expected performance.

The top view of the absorptive article manufactured by the manufacturing method concerning the embodiment of the present invention. FIG. 1B is a cross-sectional view taken along line IB-IB in FIG. 1A. The schematic side view of the external shape inspection unit which performs the external shape inspection process included in the manufacturing method which concerns on embodiment of this invention. The top view of the external form inspection unit of FIG. Schematic explaining a photographing process in time series. Schematic which shows the image acquired with the camera explaining the external shape determination process included in an external shape inspection process. Schematic explaining the fabric weight determination process included in the manufacturing method which concerns on embodiment of this invention.

  The invention will be described in more detail with reference to the above-mentioned drawings. It should be noted that these drawings may not be drawn to the same size, scale, or shape as actual components in order to facilitate understanding of the present invention and simplify the description of the drawings. I want to be.

  Hereafter, the method to manufacture the absorbent article which concerns on embodiment of this invention is demonstrated, referring drawings. In the method according to the present embodiment, the manufactured absorbent article is the disposable diaper 1.

  As shown in FIG. 1A and FIG. 1B, the disposable diaper 1 manufactured by the method according to this embodiment has a liquid-permeable top sheet 3 positioned on the skin surface side of the wearer when worn and a non-skin surface side. A liquid-impervious back sheet 5 is provided, and a liquid-absorbing absorber 11 interposed between the top sheet 3 and the back sheet 5. In addition to these, the disposable diaper 1 can include an elastic member for tightening the wearer's leg and waist, an exterior sheet on which the design is printed, and the like.

  The method according to the present embodiment includes a step of forming the top sheet 3, the back sheet 5 and the absorbent body 11, respectively, and the top sheet 3, the back sheet 5 and the absorbent body 11 in the same manner as a conventional disposable diaper manufacturing method. And a step of bonding while aligning.

  As shown in FIG. 1A, the absorbent body 11 has an overall shape like an hourglass in a plan view when the disposable diaper 1 is deployed, and a longitudinal central portion 11LC that covers the wearer's crotch when worn is Compared with the longitudinal end portion 11LE, the dimension is smaller in the lateral direction. More specifically, the absorbent body 11 includes a portion 11LC having a longitudinal direction LD and a dimension of the short direction SD perpendicular to the longitudinal direction LD changing along the longitudinal direction LD.

  The method according to this embodiment is carried after the above-described step of forming the absorbent body 11 and before the step of bonding the absorbent body 11 while aligning with other members such as the top sheet 3. A contour inspection step for determining whether or not the outer shape of the absorber 11 is acceptable from an image of the absorber 11 taken while appropriately illuminating the absorber 11 being illuminated.

  The outline inspection process is performed by the outline inspection unit 20. The outer shape inspection unit 20 includes a transport device 21 that transports the absorber 11, a single camera 23 that is installed above the transport device 21 and photographs the absorber 11, and the transport direction of the absorber 11 rather than the camera 23. Are provided with a plurality of illuminations 25 arranged on the upstream side and the downstream side, and a control device 27 that executes an outer shape determination step to be described later while controlling the above-described components of the outer shape inspection unit 20.

  Now, the outer shape inspection unit 20 used for performing the outer shape inspection process will be described in more detail. In addition, in this embodiment, in order to ensure the shape retention property of the absorber 11, the conveyed absorber 11 is covered with the conventional core wrap sheet | seat which consists of a fiber nonwoven fabric, a tissue sheet, etc., Note that the core wrap sheet is not shown.

  As shown in FIGS. 2 and 3, the outer shape inspection step is a conveyance path TW formed on the outer surface of the suction conveyor 21 that can stably convey the absorbent body 11, which is the conveyance device of the present invention. The above is performed on the absorber 11 that is continuously conveyed in the longitudinal direction LD of the absorber 11. A rotary encoder 21 </ b> E is attached to the suction conveyor 21, and the distance that the absorber 11 is conveyed by the suction conveyor 21 can be detected. The conveyance distance detected by the rotary encoder 21E is transmitted to the control device 27 described later.

  The suction conveyor 21 includes a mesh belt 21B that forms a transport path TW for placing and transporting the absorber 11, and suction means 21M that sucks the absorber 11 through the mesh belt 21B. The suction means 21M has an internal space connected to, for example, a vacuum pump or a blower, and has a plurality of through holes (not shown) for suction leading to the internal space in a portion facing the transport path TW. It is a suction box. As shown by black dots in FIG. 3, the mesh belt 21 </ b> B is formed with a through hole 21 </ b> BT that leads to the suction means 21 </ b> M and sucks the absorber 11.

  The camera 23 is an area camera that can acquire a rectangular image, and is at a distance from the transport path TW so as to capture at least the entire lateral direction SD of the absorber 11 transported on the transport path TW. It is arranged with. Particularly in the present embodiment, the camera 23 has a dimension of the imaging area PA to be imaged by the camera 23 that is half the length of the longitudinal direction LD of the absorber 11 (L / It is arranged at a distance from the absorber 11 so as to be larger than 2) and not to be able to copy the entire longitudinal direction LD of one absorber 11.

  In the present embodiment, two illuminations 25 for illuminating the imaging area PA are arranged on the transport path TW in the same manner as the camera 23. Of these two illuminations 25, one illumination 25 </ b> U is disposed upstream of the camera 23 in the conveyance direction MD of the absorber 11, and the other illumination 25 </ b> D absorbs the camera 23. It arrange | positions in the conveyance direction MD of the body 11 downstream. In the present embodiment, the illumination 25 is LED illumination.

  Moreover, in this embodiment, each illumination 25 has a bar shape, that is, a shape having a longitudinal direction in a direction orthogonal to the transport direction MD of the absorber 11, and in the transport direction MD of the absorber 11. The dimension in the orthogonal direction is larger than the dimension in the lateral direction SD of the absorbent body 11. Therefore, the absorber 11 can be illuminated by the illumination 25 over the entire short direction SD. Further, in the present embodiment, the illumination 25 is provided at a position 200 mm from the absorber 11, and the illumination area 25 illuminates with an illuminance of about 4000 lux per illumination 25. At this time, the illuminance in the photographing area PA by one illumination 25 is preferably 2000 lux to 6000 lux. When the illuminance is 2000 lux or more, it is possible to illuminate the outer shape of the absorber 11 so that the outer shape of the absorber 11 can be clearly photographed in the photographing area PA. On the other hand, when the illuminance is 6000 lux or less, it is possible to prevent the outline of the absorber 11 from being recognized due to whiteout of the outline of the absorber 11. In the present embodiment, these illuminations 25 are controlled by the control device 27 so as to illuminate the imaging area PA with the above illuminance.

  The control device 27 is a PLC (programmable logic controller) including a CPU (microprocessor), a memory, an input port, an output port, and the like. The control device 27 is connected to each component of the contour inspection unit 20 in order to control the operation of the contour inspection unit 20, receives data from each component, and transmits a control signal to each component. Specifically, in the present embodiment, the control device 27 receives data on the transport distance of the absorber 11 from the rotary encoder 21E, image data taken by the camera 23 from the camera 23, and the like. Then, the control device 27 transmits a control signal for instructing photographing timing to the camera 23, a control signal for adjusting illuminance to the illumination 25, and the like. Moreover, the control apparatus 27 can determine whether the external shape of the absorber 11 is permissible based on the image image | photographed with the camera 23 by the external shape determination process mentioned later.

  From this, the external shape inspection process which inspects the external shape of each absorber 11 is demonstrated in detail. The outline inspection process includes the camera arrangement process for arranging the camera 23 as described above and the illumination arrangement process for arranging the illumination 25 as described above.

  The outer shape inspection process further includes an imaging process in which each absorber 11 is imaged using the camera 23 and an entire image of each absorber 11 is acquired.

  In order to execute the photographing process, the control device 27 determines that the camera 23 has a length L per absorber 11 based on the transport distance of the absorber 11 transmitted from the rotary encoder 21E. As described above, a control signal for instructing the timing of shooting is transmitted to the camera 23 so that each half (L / 2) is taken. Therefore, the image is taken twice for each absorber 11, and as described above, the dimension in the longitudinal direction LD of the absorber 11 in the imaging region PA is half the length L per absorber 11 (L / 2), a part of the absorber 11 is photographed by overlapping the longitudinal direction LD of the absorber 11 in a plurality of images, so that the entire absorber 11 can be photographed. it can. And the control apparatus 27 acquires the image image | photographed with the camera 23. FIG.

  4 (a) to 4 (d) show the photographing steps in time series to assist in understanding the description of the photographing step described above, and the images are continuously conveyed when sequentially photographed by the camera 23. FIG. The state of the absorbers 111-114 currently conveyed by direction MD is shown. Of the absorbers 111 to 114, the absorber 111 is the absorber 11 located on the most downstream side, and the absorber 114 is the absorber 11 located on the most upstream side. Specifically, FIG. 4 (a) images the downstream portion of the absorber 112, FIG. 4 (b) images the upstream portion of the absorber 112, and FIG. 4 (c) illustrates the absorption. The downstream part of the body 113 is imaged, and FIG. 4D is an image of the upstream part of the absorber 114.

  Since the absorber 11 is sequentially photographed as described above, in the present embodiment, a plurality of images of each absorber 11 acquired in the photographing process are photographed immediately before the first photographed image. It can be said that the image overlapped with the longitudinal direction LD of the absorber 11. As a specific example, the image taken in the state of FIG. 4B, in which the absorber 112 is photographed for the second time, is photographed in the state of FIG. 4A, where the absorber 112 is photographed first. The image overlaps the longitudinal direction LD of the absorber 112. The same applies to the images of the absorber 113 taken in the state of FIGS. 4C and 4D.

  The outer shape inspection step further includes an outer shape determination step for determining whether or not the outer shape of each absorber 11 is acceptable from the image acquired in the imaging step, which is performed after the imaging step. Determination of the outer shape of each absorber 11 is performed using a virtual reference frame 31 set in advance in the imaging area PA as shown in FIG. The shape of the reference frame 31 is set so as to be separated from the contour of the desired absorber 11 by an allowable error.

  Specifically, the reference frame 31 is smaller than the outer reference frame 31O for inspecting whether or not the outer shape of the absorber 11 is larger than an acceptable one, and the outer shape of the absorber 11 is smaller than an acceptable one. And an inner reference frame 31I for inspecting whether or not it is present. That is, in the outer shape inspection process, when a part of the absorber 11 is contained in the outer reference frame 31O, the outer shape of the absorber 11 is unacceptable because the outer shape of the absorber 11 is larger than an acceptable one. Judged to be. Further, if there is a part of the inner reference frame 31I that does not contain the absorber 11, the outer shape of the absorber 11 is determined to be unacceptable because the outer shape of the absorber 11 is smaller than an acceptable one. Is done. As a result, not only the outer shape of the absorber 11 itself, but also the case where the absorber 11 is turned during transportation, torn due to the tension of transportation, or to be chipped is detected. Can do.

  In the present embodiment, the shape of the outer reference frame 31O for inspecting the outer shape of the longitudinal central portion 11LC whose dimensions in the short direction change along the longitudinal direction is the central portion of the absorbent body 11 in the longitudinal direction. The ellipse is adapted to the curvature of 11LC, and the shape of the other reference frame 31 is a rectangle. As the shape of each of the reference frames 31, an arbitrary shape can be selected in consideration of the desired outer shape of the absorber 11 and an allowable error from the outer shape.

  The manufacturing method of the absorbent article which concerns on this embodiment further includes the discharge process which discharges | emits the absorber 11 judged that the external shape is not accept | permitted among the absorbers 11 after the above-mentioned external shape inspection process.

  The discharging process is performed by a discharging device (not shown) provided in a subsequent process of the outer shape inspection unit 20. The discharging device is a device that excludes the absorber 11 having a defective outer shape, in which the outer shape of the absorber 11 in the control device 27 is unacceptable, from the conveyance path of the absorber 11. The discharge device is, for example, an air blow device that blows off a defective outer shape absorber with high-pressure air, or a pusher that pushes out a defective outer shape absorber from the side surface of the conveyance path. In the present embodiment, the discharge device is controlled by the control device 27 so that the absorber having a defective outer shape is discharged from the conveyance path of the absorber 11 when the absorber whose outer shape is determined to be unacceptable passes through the discharge device. It is controlled.

  The method for manufacturing the absorbent article according to the present embodiment includes a basis weight determination step of determining whether or not the absorbent body 11 includes a portion having a predetermined basis weight or less, in addition to the above-described outer shape inspection step. As will be described below, the basis weight determination step is performed based on the image acquired using the camera 23 in the above-described photographing step.

  In the photographing process, the absorber 11 is conveyed on the mesh belt 21B, and the through hole 21BT formed in the mesh belt 21B together with the absorber 11 is also photographed. At this time, in the image acquired by the camera 23, as shown in FIG. 6, the through hole 21BT appears to be black, and as a result, the absorber 11 has a lower basis weight than other parts and the through hole. If there is a portion 11F that overlaps with 21BT, the through hole 21BT may be seen through the absorber 11 in the portion 11F. In the basis weight determination step, an image including such a portion 11F is binarized (monochrome) using a predetermined threshold value such as luminance or brightness, and the image of the binarized absorber 11 is blackened. By checking whether or not the portion 11F exists, it is possible to determine whether or not the absorbent body 11 includes a portion having a predetermined basis weight or less. In this case, a threshold value of values such as luminance and lightness when binarizing an image is determined according to a permissible basis weight that is required to be detected.

  In this embodiment, the mesh belt 21B in which the through holes 21BT for sucking the absorber 11 are formed with a predetermined distribution is used in performing the basis weight determination process. However, another type of belt, for example, A mesh mesh belt may be used.

  From this, the effect of the method which concerns on this embodiment is demonstrated.

  (1) The manufacturing method of the absorbent article which concerns on this embodiment includes the external shape inspection process of the absorber 11, and this external shape inspection process is upstream of the conveyance direction MD of the absorber 11 rather than the camera 23. The illumination arrangement | positioning process which arrange | positions the illumination 25 to both downstream is included. Thereby, by illuminating the imaging region PA from both the upstream side and the downstream side in the transport direction MD of the absorber 11, the contour line of the absorber 11 can be more appropriately illuminated. In particular, the contour line of the longitudinal center portion 11LC in which the dimension in the lateral direction SD changes along the longitudinal direction LD can be photographed more clearly. As a result, the outer shape of the portion 11LC can be photographed more accurately, and as a result, it can be determined whether or not the outer shape of the absorber 11 is acceptable more accurately.

  (2) In this embodiment, in the imaging process, as described above, each absorber 11 is imaged twice by the camera 23 so that the entire short direction SD of the absorber 11 is imaged. The whole of each absorber 11 is imaged. As a result, it is possible to photograph the absorber 11 larger than when the camera 23 is arranged further away from the absorber 11 and the entire absorber 11 is photographed only once. Therefore, even when the resolution of the camera 23 is limited, it is preferable because the contour line of the longitudinal central portion 11LC extending so as to cross the vertical and horizontal directions of the imaging area PA can be captured more smoothly and more accurately. As a result, the outer shape of the longitudinal central portion 11C having a more complicated shape than a simple rectangle can be photographed more accurately, and more accurately whether or not the outer shape of the absorber 11 is acceptable. Judgment can be made.

  (3) In the present embodiment, as described above, the two images of the respective absorbers 11 acquired in the photographing process overlap in the longitudinal direction LD of the absorber 11. As a result, the whole of each absorber 11 can be imaged, and as a result, the entire outer shape of each absorber 11 can be inspected without fail.

  (4) The manufacturing method of the absorbent article which concerns on this embodiment includes the discharge process which discharges | emits the absorber 11 judged that the external shape is not accept | permitted among the absorbers 11 after an external shape inspection process. As a result, it is possible to prevent the absorbent article including the absorbent body 11 whose outer shape is determined to be unacceptable from being shipped as a product before the step of bonding with another member.

  (5) The method for manufacturing the absorbent article according to the present embodiment includes a basis weight determining step of determining whether or not the absorbent body 11 includes a portion having a predetermined basis weight or less. As a result, it is possible to detect the absorber 11 including a portion having a predetermined basis weight or less, and in the discharging step of discharging the absorber 11 including the portion having a predetermined basis weight or less, a portion having a predetermined basis weight or less is included. It can prevent shipping the absorbent article containing the absorber 11 as a product before the process of bonding with another member.

  (6) In this embodiment, in order to convey the absorber 11 stably, the suction conveyor 21 was used for the conveying apparatus which conveys the absorber 11. FIG. As a result, the absorber 11 being transported moves unintentionally due to vibrations of the transport device, etc., thereby preventing the position of the absorber 11 from deviating from the assumed location in the image acquired by the camera 23, As a result, the outer shape inspection of the absorber 11 can be performed stably.

  Moreover, as shown in FIG. 2, the optical axis OA of the illumination 25U arranged on the upstream side in the transport direction MD of the absorber 11 is tilted in the downstream direction in the transport direction MD of the absorber 11, and absorption is performed. It is preferable that the optical axis OA of the illumination 25D arranged on the downstream side in the transport direction MD of the body 11 is inclined in the upstream direction in the transport direction of the absorber. This is because the illumination 25U and 25D illuminate from both the upstream side and the downstream side toward the edge of the longitudinal center portion 11C of the absorbent body 11 where the short dimension SD of the absorbent body 11 is changing. This is because the outline of the absorber 11 can be taken clearly. However, depending on the spread of the luminous flux due to the structure of the illumination 25, there may be a case where the lower part of the camera 23 can be appropriately illuminated without tilting the luminous flux of the illumination 25 as described above. Therefore, the optical axis OA of the illumination 25 may not be inclined as shown in FIG. 2, and may extend directly below.

  Similarly, in order to clearly capture the outline of the absorber 11, the inclination angle α (FIG. 2) of the optical axis OA of the illumination 25 from the vertical direction is more preferably 20 degrees to 40 degrees.

  In the present invention, the “illumination optical axis” is a virtual light beam that is representative of the luminous flux emitted from the illumination 25, that is, emitted from the illumination starting from the central portion of the illuminated portion. An imaginary line extending in the direction in which the light beam travels shall be said.

  Further, when the optical axis OA of the illumination 25 is tilted as described above, the optical axis OA of the illumination 25U arranged on the upstream side in the transport direction MD of the absorber 11 and the transport direction of the absorber 11 More preferably, the optical axis OA of the illumination 25D disposed on the downstream side of the MD does not intersect the transport direction MD of the absorber 11 before reaching the absorber 11. If the optical axes OA of the illuminations 25U and 25D intersect in the transport direction MD of the absorber 11 before reaching the absorber 11, the light just below the camera 23, that is, in the central region of the imaging area PA. This is because the amount of light becomes larger than other areas, and the imaging area PA cannot be illuminated uniformly, and the contour line of the absorber 11 may not be clearly imaged. In addition, “the optical axes OA (to each other) do not intersect in the transport direction MD of the absorber 11” specifically means that the optical axis OA of the illumination 25D located on the downstream side of the transport direction MD of the absorber 11 is. The point where the absorber 11 reaches the absorber 11 is more downstream than the point where the optical axis OA of the illumination 25U located on the upstream side in the transport direction MD of the absorber 11 reaches the absorber 11. Means to be located in Conversely, the same applies to the optical axis OA of the illumination 25U located on the upstream side.

  The manufacturing method of the absorbent article which concerns on the above-mentioned embodiment includes the basis weight judgment process of judging whether the absorber 11 contains the part below a predetermined basic weight as mentioned above. In another embodiment, only the outline inspection process is included, and the basis weight determination process is not included.

  The manufacturing method of the absorbent article which concerns on the above-mentioned embodiment WHEREIN: The absorber 11 in which the external shape was judged to be unacceptable among the absorber 11, and the absorber 11 containing a part below a predetermined basic weight from a conveyance path. Includes a discharging process. In the discharge process of another embodiment, either one of the absorbent body 11 determined to have an unacceptable outer shape and the absorbent body 11 including a portion having a predetermined basis weight or less is discharged. In yet another embodiment, the method for manufacturing an absorbent article does not include the discharging step.

  In the above-described embodiment, the camera 23 is used to photograph each absorber 11 twice. However, if the resolution of the image acquired by the camera 23 is sufficiently high, the outer shape of the absorber 11 including the central portion 11LC in the longitudinal direction is obtained by an image acquired by capturing the entire absorber 11 only once. Thus, the inspection can be performed with sufficiently high accuracy. In this case, as another embodiment, in the camera placement process, the camera 23 is placed at a distance from the transport path TW that can capture the entire length direction LD and width direction SD of one absorber 11, and photographing. In the process, each absorber 11 is photographed only once.

  In yet another embodiment, each absorber 11 is imaged three or more times in the imaging process. By doing in this way, in the fixed resolution, compared with the case where each absorber 11 is imaged twice, the outer shape of the absorber 11, in particular, the boundary line of the longitudinal center portion 11LC of the absorber 11, It is larger and can be taken clearly. In this case, if the length of the imaging region PA in the longitudinal direction of the absorber 11 is larger than the length L of the longitudinal direction LD of the absorber 11 divided by the number of imaging per absorber 11, A plurality of images for each absorber 11 can be overlapped in the longitudinal direction LD of the absorber 11. That is, as in the above-described embodiment, three or more images of each absorber 11 are overlapped in the longitudinal direction LD of the absorber 11 except for the first imaged image. be able to. As a result, it is preferable because the entire absorber 11 can be imaged, and as a result, the entire outer shape of each absorber 11 can be completely inspected. However, the length in the longitudinal direction LD of the absorber 11 in the imaging area PA may be the same as the length L obtained by dividing the length L in the longitudinal direction LD of the absorber 11 by the number of times of imaging per absorber 11.

  In the above-mentioned embodiment, in order to convey the absorber 11 stably, the suction conveyor 21 was used for the conveying apparatus which conveys the absorber 11. FIG. However, the transport device is not limited to the suction conveyor 21 as long as the absorber 11 can be transported stably. For example, a normal belt conveyor may be used, or a driving nip roller that conveys the absorbent body 11 by rotating the absorbent body 11 before and after the region photographed by the camera 23 may be used.

  In the above-described embodiment, the illumination 25 has a bar shape, but the present invention is not limited to this shape. For example, the illumination may be illumination of other shapes such as a donut shape or a panel (plate) shape as long as it can illuminate the photographing region evenly. However, it is preferable that the illumination 25 has a bar shape, since it can be illuminated uniformly with respect to the short direction SD of the absorber 11.

  In the embodiment described above, the illumination 25 is LED illumination, but may be other types of light sources such as a fluorescent lamp and a mercury lamp. However, it is preferable that the LED illumination is less illuminance unevenness and a decrease in illuminance due to long-time use than that of other light sources, and it is not necessary to replace it more frequently.

  Furthermore, in the above-described embodiment, the outer shape inspection unit 20 is disposed on the downstream side of the illumination direction 25U disposed in the transport direction MD of the absorber 11 and the downstream side in the transport direction MD of the absorber 11 with respect to the camera 23. Two illuminations 25 are provided with the illumination 25D being provided. However, in order to increase the amount of light in the imaging area PA and / or equalize the amount of light, the outer shape inspection unit 20 transmits one or more illuminations other than these two illuminations upstream, downstream, Alternatively, both the upstream side and the downstream side may be provided.

  In the above-described embodiment, the components of the outer shape inspection unit 20 such as the camera 23 and the illumination 25 are controlled by the single control device 27. However, each component of the outer shape inspection unit 20 includes a control device separately. It may be. Further, the control device 27 may be automatically operated by a program created in advance, or may be manually operated with respect to some control such as adjustment of the illuminance of the illumination 25.

  In the above-described embodiment, the control device 27 is a PLC, but may be a computer or the like that can perform the same operation as the PLC.

  In the above-described embodiment, the manufactured absorbent article 1 was a disposable diaper. In another embodiment, the absorbent article 1 manufactured by the method according to the present invention is another type of absorbent article including an absorbent body such as a sanitary napkin and a urine pad.

  All features that can be understood by those skilled in the art from the description, drawings, and claims are described in the specification in which these features are combined only in relation to certain other features. As long as the features are not explicitly excluded, or unless the technical aspects are impossible or meaningless combinations, independently and in addition to one or more of the other disclosed herein. It can be combined with any combination of features.

  The present invention is defined as follows.

<1> A method for producing an absorbent article using an absorbent body having a longitudinal direction and including a portion in which a dimension in a short direction perpendicular to the longitudinal direction varies along the longitudinal direction,
In the method for manufacturing the absorbent article, each of the absorbers can be obtained by photographing the absorber continuously conveyed in the longitudinal direction on a conveyance path with a plurality of lights while photographing with a single camera. Including an outer shape inspection process for inspecting the outer shape of
The outline inspection process includes
A camera placement step of placing the one camera above the transport path at a distance that allows the entire length of the absorber to be copied in the short direction;
An illumination arrangement step of arranging the plurality of illuminations on the upstream side and the downstream side in the conveying direction of the absorber, rather than the one camera,
Using the one camera, photographing each of the absorbers, and obtaining a whole image of each absorber,
An outer shape determination step for determining whether or not the outer shape of each absorber is acceptable from the image acquired in the photographing step;
Including at least
A method of manufacturing an absorbent article.

<2> In the camera placement step, the one camera is further installed with a distance that cannot copy the entire longitudinal direction of the one absorber.
In the photographing step, photographing a plurality of times for each of the absorbers,
The method to manufacture the absorbent article as described in <1>.

<3> In the photographing step, the respective absorbers are continuously photographed,
A plurality of images of each of the absorbers acquired in the imaging step are overlapped in the longitudinal direction of the absorber with the image captured immediately before, except for the first captured image.
The method to manufacture the absorbent article as described in <2>.

<4> Among the plurality of illuminations, an optical axis of illumination arranged on the upstream side in the transport direction of the absorber is tilted in the downstream direction in the transport direction of the absorber,
Among the plurality of illuminations, the optical axis of illumination disposed on the downstream side in the transport direction of the absorber is inclined in the upstream direction in the transport direction of the absorber,
The method to manufacture the absorbent article as described in any one of <1>-<3>.

<5> The optical axis of illumination arranged on the upstream side in the conveyance direction MD of the absorber and the optical axis of illumination arranged on the downstream side in the conveyance direction MD of the absorber are in the absorber. Do not intersect in the transport direction of the absorber before reaching
The method to manufacture the absorbent article as described in <4>.

<6> The inclination angles from the vertical direction of the optical axes of the plurality of illuminations are 20 degrees to 40 degrees, respectively.
<4> or the method to manufacture the absorbent article as described in <5>.

<7> The plurality of lights are LED lights.
The method to manufacture the absorbent article as described in any one of <1>-<6>.

<8> The illuminance at a location where an image is acquired by the camera is 2000 lux to 6000 lux.
The method to manufacture the absorbent article as described in any one of <1>-<7>.

<9> Each of the plurality of lights has a shape having a longitudinal direction in a direction orthogonal to the transport direction,
The dimension in the direction orthogonal to the transport direction of the plurality of illuminations is larger than the dimension in the short direction of the absorber.
The method to manufacture the absorbent article as described in any one of <1>-<8>.

<10> Further, in the outer shape determination step, a discharge step of discharging the absorber, of which the outer shape is determined to be unacceptable, is included.
The method to manufacture the absorbent article as described in any one of <1>-<9>.

<11> Furthermore, based on the image acquired in the imaging step, the basis weight determination step of determining whether or not the absorber includes a portion having a predetermined basis weight or less,
The method to manufacture the absorbent article as described in any one of <1>-<10>.

<12> Furthermore, in the basis weight determination step, a discharge step of discharging the absorber determined to include a portion having a predetermined basis weight or less is included.
<11> A method for producing the absorbent article according to the above.

1 Disposable diaper (absorbent article)
11, 111, 112, 113, 114 Absorber 23 Camera 25, 25D, 25U Illumination LD Absorber longitudinal direction SD Absorber short direction TW Conveyance path

Claims (9)

A method of manufacturing an absorbent article using an absorbent body having a longitudinal direction and including a portion in which a dimension in a short direction perpendicular to the longitudinal direction varies along the longitudinal direction,
In the method for manufacturing the absorbent article, each of the absorbers can be obtained by photographing the absorber continuously conveyed in the longitudinal direction on a conveyance path with a plurality of lights while photographing with a single camera. Including an outer shape inspection process for inspecting the outer shape of
The outline inspection process includes
A camera placement step of placing the one camera above the transport path at a distance that allows the entire length of the absorber to be copied in the short direction;
An illumination arrangement step of arranging the plurality of illuminations on the upstream side and the downstream side in the conveying direction of the absorber, rather than the one camera,
Using the one camera, photographing each of the absorbers, and obtaining a whole image of each absorber,
An outer shape determination step for determining whether or not the outer shape of each absorber is acceptable from the image acquired in the photographing step;
Including at least
The absorbent body is continuously transported in the longitudinal direction on the transport path, which is on a mesh belt having a plurality of through holes,
By checking whether or not the through-hole is shown through the part based on an image including a part overlapping the through-hole in the absorber obtained in the photographing step, the absorber Further includes a basis weight determining step of determining whether or not includes a portion having a predetermined basis weight or less,
A method of manufacturing an absorbent article. In the camera placement step, the one camera is further installed with a distance that cannot capture the entire longitudinal direction of the one absorber.
In the photographing step, photographing a plurality of times for each of the absorbers,
A method for producing the absorbent article according to claim 1. In the photographing step, each of the absorbers is photographed continuously,
A plurality of images of each of the absorbers acquired in the imaging step are overlapped in the longitudinal direction of the absorber with the image captured immediately before, except for the first captured image.
A method for producing the absorbent article according to claim 2. The inclination angles from the vertical direction of the optical axes of the plurality of illuminations are 20 degrees to 40 degrees, respectively.
The method to manufacture the absorbent article of any one of Claims 1-3. The plurality of lights are LED lights,
The method to manufacture the absorbent article of any one of Claims 1-4. The illuminance at a location where an image is acquired by the camera is 2000 lux to 6000 lux.
The method to manufacture the absorbent article of any one of Claims 1-5. Each of the plurality of illuminations has a shape having a longitudinal direction in a direction orthogonal to the transport direction,
The dimension in the direction orthogonal to the transport direction of the plurality of illuminations is larger than the dimension in the short direction of the absorber.
The method to manufacture the absorbent article of any one of Claims 1-6. Further, the outer shape determination step includes a discharging step of discharging the absorber whose outer shape is determined to be unacceptable among the absorbers.
The method to manufacture the absorbent article of any one of Claims 1-7. Furthermore, in the basis weight determining step, including a discharging step of discharging the absorber determined to include a portion of a predetermined basis weight or less of the absorber.
The method to manufacture the absorbent article as described in any one of Claims 1-8 .

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