WO2016042905A1

WO2016042905A1 - Method for manufacturing absorbent article

Info

Publication number: WO2016042905A1
Application number: PCT/JP2015/070326
Authority: WO
Inventors: 知弘渡部; 健二郎駿河
Original assignee: ユニ・チャーム株式会社
Priority date: 2014-09-19
Filing date: 2015-07-15
Publication date: 2016-03-24
Also published as: JP5901717B1; JP2016059708A

Abstract

The present invention relates to a method for manufacturing an absorbent article, which involves an inspection step of carrying out an outer shape inspection and a contamination inspection of an object (11c) of interest, which is an absorbent article (1) itself or a constituent member of the absorbent article, in parallel with each other during the delivery of the object of interest, wherein the object of interest has a first surface (F1) and a second surface (F2) that is opposed to the first surface. The inspection step comprises: an image-taking step of taking an image of the first surface of the object of interest with a first camera (21) that is placed on the first surface side of the object of interest; an outer shape determination step of determining whether or not the outer shape of the object of interest is acceptable from the image taken with the first camera in the image-taking step; a surface contamination detection step of detecting the presence or absence of contaminants on at least the first surface of the object of interest; and an inside contamination detection step of detecting the presence or absence of contaminants in the inside of the object of interest.

Description

Method for manufacturing an absorbent article

The present invention is an inspection that inspects whether the outer shape of the absorbent article itself or the inspection object that is a constituent member of the absorbent article is acceptable and whether or not there is a foreign substance on the surface and inside of the inspection object. The present invention relates to a method for producing an absorbent article including a step.

Conventionally, an apparatus and a method for inspecting a component (online web) of an absorbent article being conveyed using a camera (line scan camera) are known (see, for example, Patent Document 1).

Today, in order to improve the quality of absorbent articles such as disposable diapers and sanitary napkins, in the process of manufacturing absorbent articles, the absorbent article itself or the inspection object that is a constituent member of the absorbent article. It is required to inspect both whether the outer shape is acceptable and whether there is a foreign object on the surface and inside of the inspection object. In order to realize this requirement, for example, an inspection unit 100 as schematically shown in FIG. 6 is conventionally used.

The inspection unit 100 in FIG. 6 is continuously conveyed, and the outer shape of the inspection object according to the embodiment of the present invention to be described later is acceptable, and the presence or absence of foreign matter on the surface and inside of the inspection object. Both are inspected. In addition, the said inspection target object has the 1st surface F1 and the 2nd surface F2 on the opposite side of the 1st surface F1 in the conveyance direction MD similarly to the inspection target object in embodiment of this invention mentioned later. It is the absorber 11c being conveyed.

The inspection unit 100 in FIG. 6 illuminates the first camera 101 that images the absorber 11c from the first surface F1 side, and the imaging area of the first camera 101 from the first surface F1 side of the absorber 11c. The first illumination 103, the second camera 105 that photographs the absorber 11c from the second surface F2 side, and the second illumination that illuminates the imaging region of the second camera 105 from the second surface F2 side of the absorber 11c. The second illumination 107, the third camera 109 different from the second camera 105 that images the absorber 11c from the second surface F2 side, and the imaging area of the third camera 109 on the first surface of the absorber 11c. And a third illumination 111 for photographing from the F1 side. The third illumination 111 has an amount of light that allows the illumination light to pass through the absorber 11c.

Thus, by analyzing the image acquired by the first camera 101, the image acquired by the second camera 105 is analyzed for the outer shape of the absorber 11c and the presence or absence of foreign matter on the first surface F1. By analyzing the outer shape of the absorber 11c and the presence or absence of foreign matter on the second surface F2, and by analyzing the image acquired by the third camera 109, the presence or absence of foreign matter inside the absorber 11c can be detected.

Special table 2013-513188 gazette

However, in the inspection unit of FIG. 6, a large space for installing the three

cameras

101, 105, 109 and the three

lights

103, 107, 111 is required in the manufacturing equipment for absorbent articles. Reduction has become an issue. Furthermore, a great cost is required to introduce these three cameras and illumination, and the inspection unit becomes complicated.

Therefore, the object of the present invention is to determine the outer shape of the object to be inspected and the presence or absence of foreign matter in the absorbent article itself or the component of the absorbent article with less illumination and camera installation space and introduction costs than in the past. It is providing the manufacturing method of an absorbent article including the inspection process which can be test | inspected.

In order to achieve the above object, the present invention provides:
External inspection and foreign object inspection of an inspection object, which is an absorbent article itself or a constituent member of the absorbent article, having a first surface and a second surface opposite to the first surface, A method of manufacturing an absorbent article including an inspection process performed in parallel during the transportation of an object,
The inspection step is
A camera arrangement step of arranging a first camera on the first surface side of the inspection object so as to photograph the first surface;
The first illumination on the first surface side of the inspection object and the second surface side of the inspection object so as to illuminate the region of the inspection object photographed by the first camera An illumination arrangement step of arranging the second illumination;
A light amount adjustment step of adjusting the light amounts of the first illumination and the second illumination so that the first camera can sense the illumination light transmitted through the inspection object from the second illumination;
An imaging step of imaging the first surface of the inspection object so as to include the outer shape of the inspection object using the first camera;
From the image acquired by the first camera in the photographing step, an outer shape determination step for determining whether or not the outer shape of the inspection object is acceptable;
From the image acquired by the first camera in the photographing step, a surface foreign matter detection step of detecting the presence or absence of foreign matter on at least the first surface of the inspection object;
From the image acquired by the first camera in the photographing step, an internal foreign matter detection step for detecting the presence or absence of foreign matter inside the inspection object;
including,
A method of manufacturing an absorbent article is provided.

In order to achieve the above object, the present invention further provides:
External inspection and foreign object inspection of an inspection object, which is an absorbent article itself or a constituent member of the absorbent article, having a first surface and a second surface opposite to the first surface, A method of manufacturing an absorbent article including an inspection process performed in parallel during the transportation of an object,
The inspection step is
The first camera is photographed so as to photograph the first surface on the first surface side of the inspection object, and the second surface is photographed on the second surface side of the inspection object. A camera placement step of placing a second camera as
On the first surface side of the inspection object, first illumination for illuminating a region of the inspection object photographed by the first camera, and on the second surface side of the inspection object, An illumination arrangement step of arranging a second illumination that illuminates the region of the inspection object imaged by the second camera;
A light amount adjustment step of adjusting the light amounts of the first illumination and the second illumination so that the first camera can sense the illumination light transmitted through the inspection object from the second illumination;
Using the first camera and the second camera, an imaging step of photographing the first surface and the second surface of the inspection object so as to include the outer shape of the inspection object;
An outer shape determination step for determining whether or not the outer shape of the inspection object is acceptable from either one or both of the images acquired by the first camera and the second camera in the photographing step;
Surface foreign matter detection for detecting the presence or absence of foreign matter on at least the first surface and the second surface of the inspection object from images acquired by the first camera and the second camera in the photographing step. Process,
From the image acquired by the first camera in the photographing step, an internal foreign matter detection step for detecting the presence or absence of foreign matter inside the inspection object;
including,
A method of manufacturing an absorbent article is provided.

Furthermore, in the camera arrangement step, it is preferable that the distance between the first camera and the second camera in the conveyance direction of the inspection object is shorter than the conveyance repetition unit length of the inspection object. Thereby, since the first camera and the second camera can simultaneously shoot at least a part of the same transportation object transport repeat unit, from the images taken by the first and second cameras, It becomes easy to recognize the conveyance repeating unit of the same inspection object. In the present disclosure, the “inspection object conveyance repeating unit” is an inspection object used to form one absorbent article, and is continuously or intermittently used in the manufacturing process of the absorbent article. Each of a plurality of inspection objects being repeatedly conveyed means each of the inspection object conveyance repeating unit lengths, and the length of one inspection object conveyance repeating unit in the conveyance direction is meant.

Furthermore, in the camera arrangement step, it is preferable that the first camera and the second camera are arranged on one straight line perpendicular to the conveyance direction of the inspection object. Thereby, the installation space of the camera is not expanded in the conveyance direction of the inspection object, and the installation space of the camera can be further reduced.

Furthermore, the intersection of the optical axis of the first illumination and the first surface of the inspection object, and the intersection of the optical axis of the second illumination and the second surface of the inspection object are It is preferable to be located on a straight line connecting the first camera and the second camera. Thereby, the said imaging | photography area | region can be illuminated most efficiently by matching the imaging | photography area | region of the camera on the 1st and 2nd surface of the said test target object with the optical axis of illumination.

The inspection object is the absorbent article itself, and the absorbent article has a liquid-permeable top sheet on the second surface, a liquid-impermeable back sheet on the first surface, and the top. It is preferable to have a liquid-absorbing absorber interposed between the sheet and the back sheet. As a result, in the absorbent article, in particular, the foreign matter inspection of the surface of the top sheet that touches the skin surface of the wearer reflects the illumination light from the second illumination, not the image acquired by the first camera, on the top sheet. By using the image acquired by the second camera, which is mapped by the illumination light, it can be performed with higher accuracy.

Furthermore, the light quantity of the first illumination is preferably smaller than the light quantity of the second illumination. Thereby, since the first camera can sense the illumination light transmitted through the inspection object from the second illumination, the inside of the inspection object is analyzed by analyzing the image acquired by the first camera in the photographing process. It is possible to detect the presence or absence of foreign matter in

Furthermore, it is preferable that the first camera and the second camera are line cameras. Thereby, the installation space of the camera can be further reduced as compared with the area camera.

Furthermore, each of said 1st illumination and said 2nd illumination is a shape which has a longitudinal direction in the direction which cross | intersects the conveyance direction of the said test object, The said test | inspection of said 1st illumination and said 2nd illumination It is preferable that the dimension in the direction intersecting the conveyance direction of the object is larger than the dimension in the direction intersecting the conveyance direction of the inspection object. Thereby, the whole of the direction which cross | intersects the conveyance direction of the said test target object can be illuminated uniformly.

Furthermore, the first illumination and the second illumination are preferably LED illumination. Thereby, compared with other types of light sources such as a fluorescent lamp and a mercury lamp, there is less illuminance unevenness and a decrease in illuminance due to long-term use, and it is not necessary to change the illumination more frequently.

Further, the method includes a step of discharging the inspection object in which the outer shape is determined to be unacceptable in the outer shape determination step, and / or a surface foreign matter detection step of the inspection object. It is preferable to include a step of discharging the inspection object in which the foreign matter is detected in the step and / or a step of discharging the inspection target in which the foreign matter is detected in the internal foreign matter detection step of the inspection target. Accordingly, it is possible to prevent an absorbent article including an absorbent body that has been determined to be defective in outer shape and / or foreign matter from being shipped as a product before the step of bonding with another member.

The inspection object is a liquid-absorbent absorber used for manufacturing the absorbent article, and the plurality of absorbers are covered with a continuous sheet that is continuous in the conveyance direction of the absorber. It is preferable that it is conveyed. Thereby, an absorber can be conveyed continuously and an inspection process can be performed to each absorber.

Since the manufacturing method of the absorbent article of the present invention can install the camera and illumination in one place, the absorbent article being transported with less illumination and camera installation space and introduction cost than before. It is possible to inspect the outer shape of the inspection object that is itself or a constituent member of the absorbent article and the presence or absence of foreign matter.

The top view of the absorptive article manufactured by the manufacturing method concerning a first 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 test | inspection unit which performs the test | inspection process included in the manufacturing method of an absorbent article based on 1st embodiment of this invention. The expansion schematic side view which illustrates the irradiation range of 1st and 2nd illumination. Schematic which shows the image acquired with the camera explaining the external shape determination process included in the manufacturing method of an absorbent article based on embodiment of this invention. The schematic side view of the test | inspection unit which performs the test | inspection process included in the manufacturing method of an absorbent article based on 2nd embodiment of this invention. The schematic side view of the conventional test | inspection unit which performs the test | inspection process included in the manufacturing method of an absorbent article.

The present 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.

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

As shown in FIGS. 1A and 1B, the disposable diaper 1 manufactured by the method according to the first embodiment has a longitudinal direction LD and a lateral direction SD perpendicular to the longitudinal direction LD, and is worn by the wearer when worn. A liquid-permeable top sheet 3 positioned on the skin surface side, a liquid-impermeable back sheet 5 positioned on the non-skin surface side, and a liquid-absorbing absorption interposed between the top sheet 3 and the back sheet 5 A body 11c. 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 which concerns on 1st embodiment is the same as the manufacturing method of the conventional disposable diaper, The process of forming the top sheet 3, the back sheet 5, and the absorber 11c, respectively, These top sheet 3, the back sheet 5, and an absorber And laminating 11c while aligning.

The method according to the first embodiment is after the above-described step of forming the absorbent body 11c, and before the step of bonding the absorbent body 11c while aligning with other members such as the top sheet 3. It further includes an inspection process in which an outer shape inspection and a foreign matter inspection of the absorber 11c are performed in parallel from an image of the absorber 11c photographed while appropriately illuminating the absorber 11c being intermittently conveyed. In addition, the conveyed absorber 11c, which is an inspection object in the inspection process of the first embodiment, is a known material made of a fiber nonwoven fabric or a tissue sheet in order to ensure the shape retention of the absorber 11c and the like. It is covered with a core wrap sheet 11s. The core wrap sheet 11s is a continuous sheet that is continuous in the conveyance direction MD of the absorbent body 11c, and the composite continuum 11 composed of the multiple absorbent bodies 11c and the core wrap sheet 11s is transported to form the multiple absorbent bodies 11c. Can be continuously conveyed. Since the core wrap sheet 11s is very thin, the absorber 11c that is still covered with the core wrap sheet 11s can be visually recognized in the inspection process, and thus the absorber 11c can be inspected in this state.

In the first embodiment, the inspection process is performed by the inspection unit 20 shown in FIG. The inspection unit 20 is positioned on the first camera 21 and the first illumination 23 positioned on the first surface F1 side that is the upper surface of the absorber 11c, and on the second surface F2 side that is the lower surface of the absorber 11c. A second camera 25 and a second illumination 27 are provided. The inspection unit 20 further controls the conveyance device 29 that conveys the absorbent body 11c in the conveyance direction MD and the operation of the inspection unit 20 while performing an outer shape determination step, a surface foreign matter detection step, and an internal foreign matter detection step that will be described later. Device 31. In this inspection process, the absorbent body 11c absorbs in a so-called “longitudinal flow” so that the transport direction MD of the absorbent body 11c coincides with the longitudinal direction LD of the absorbent body 11c (that is, the disposable diaper 1). It is conveyed with the interval of product length Lp which is the conveyance repeating unit length of the body 11c, and is the length from one end of the longitudinal direction LD of one absorbent article to the other end.

The first camera 21 is disposed so as to photograph the first surface F1 of the absorber 11c, and the second camera 25 is disposed so as to photograph the second surface F2 of the absorber 11c. Yes. As shown in FIG. 2, the first and

second cameras

21 and 25 are oriented so as to face the first and second surfaces F1 and F2 of the absorber 11c in the vertical direction, respectively. In the first embodiment, the first and

second cameras

21 and 25 are both line cameras that can continuously shoot the entire lateral direction SD of the absorber 11c conveyed in the conveyance direction MD. . Thereby, the whole of the first and second surfaces F1 and F2 of the absorber 11c passing in front of the first and

second cameras

21 and 25 can be photographed so as to include the outer shape of the absorber 11c. . Further, as shown in FIG. 2, the first camera 21 and the second camera 25 are arranged apart by a distance Lc in the transport direction MD of the absorber 11c.

The first and

second illuminations

23 and 27 illuminate the imaging areas of the first and

second cameras

21 and 25 on the first and second surfaces F1 and F2 of the absorber 11c, respectively. The second illumination 27 is further configured so that illumination light transmitted through the absorber 11 c from the second illumination 27 can reach the first camera 21. This is a configuration necessary for performing an internal foreign matter detection process described later in the inspection process according to the first embodiment. As described above, the first and

second cameras

21 and 25 are arranged so as to be separated by Lc in the conveyance direction MD of the absorber 11c, and the first illumination 23 also illuminates the imaging region of the first camera 21. Thus, since it is installed in the vicinity of the first camera 21, it seems that the illumination light from the second illumination 27 does not reach the first camera 21 at first glance. However, as shown by a dotted line in FIG. 3, the illumination light emitted from the first and

second illuminations

23 and 27 has a certain spread, and the illumination light from the second illumination 27 is further reflected on the illumination light. The illumination light from the second illumination 27 is appropriately selected by appropriately selecting the installation positions, irradiation directions, and light amounts of the first and

second illuminations

23 and 27 so that the imaging range of the first camera 21 can be illuminated. The camera 21 can be reached. In the first embodiment, the first and

second cameras

23 and 27 are arranged so that the imaging areas of the first and

second cameras

21 and 25 are illuminated equally. 25 from the upstream side and the downstream side in the transport direction MD.

In the first embodiment, each of the first and

second illuminations

23 and 27 has a bar shape, that is, a shape having a longitudinal direction in a direction intersecting the transport direction MD. And the dimension of the direction which cross | intersects conveyance direction MD of the 1st and

2nd illuminations

23 and 27 is larger than the dimension of the transversal direction SD of the absorber 11c, ie, the direction which cross | intersects conveyance direction MD. Thereby, since the whole short direction SD of the absorber 11c can be illuminated uniformly, it is preferable.

In the first embodiment, the first and

second illuminations

23 and 27 are LED illuminations. This is preferable as compared with other types of light sources, since there is less illuminance unevenness and lowering of illuminance due to long-term use, and there is no need to frequently change the illumination.

The transport device 29 is a device that can transport the absorber 11c in the transport direction MD by driving the composite continuum 11 while applying tension so as not to bend. Moreover, since the conveyance apparatus 29 conveys the composite continuous body 11 floating so that both the 1st surface F1 and the 2nd surface F2 of the absorber 11c can be image | photographed, it is downward, such as a belt conveyor and a receiving plate. Therefore, the composite continuum 11 is not included. In the first embodiment, the transport device 29 is two pairs of nip rolls arranged on the upstream side and the downstream side of the imaging region of the first and

second cameras

21 and 25 in the transport direction of the absorber 11c. For example, the transport device 29 is provided with a rotary encoder 29e that can detect the transport distance of the absorber 11c from the number of rotations of the nip roll.

The control device 31 is connected to each component of the inspection unit 20 in order to control the operation of the inspection unit 20, receives data from each component, and transmits a control signal to each component. Specifically, the control device 31 receives image data captured by the

cameras

21 and 25, data on the transport distance of the absorber 11c from the rotary encoder 29e, and the like. Further, the control device 31 transmits a control signal for starting and stopping shooting to the

cameras

21 and 25, and a control signal for adjusting the illuminance to the

illuminations

23 and 27. In the first embodiment, the control device 31 is a PLC (programmable logic controller) including a CPU (microprocessor), a memory, an input port, an output port, and the like.

Hereafter, the case where an inspection process is performed using the inspection unit 20 in the first embodiment will be described in detail. In the inspection process, after performing the camera placement process, the illumination placement process, and the light quantity adjustment process, the imaging process is performed, and using the image obtained in the imaging process, the outer shape determination process, the surface foreign matter detection process, and the internal foreign matter detection process In parallel. In the inspection process of the first embodiment, the discharge process is performed after the outer shape determination process, the surface foreign object detection process, and the internal foreign object detection process.

First, in the inspection process of the first embodiment, a camera arrangement process and an illumination arrangement process are performed. In the camera placement step, as described above, the first camera 21 and the second surface of the absorber 11c are photographed on the first surface F1 side of the absorber 11c so as to photograph the first surface F1 of the absorber 11c. On the F2 side, the second camera 25 is arranged so as to photograph the second surface F2 of the absorber 11c. In the illumination arrangement step, as described above, the first illumination 23 that illuminates the region of the absorber 11c captured by the first camera 21 on the first surface F1 side of the absorber 11c, and the absorber 11c. The second illumination 27 for illuminating the region of the absorber 11c photographed by the second camera 25 is disposed on the second surface side F2. Note that the order of the camera placement process and the illumination placement process can be determined from the viewpoint of ease of work in these processes, and either the camera placement process or the illumination placement process may be performed first.

In the inspection process of the first embodiment, the light amount adjustment process is performed after the camera arrangement process and the illumination arrangement process. In the light amount adjustment process, the first camera 21 can sense the light amount of the first and

second illuminations

23 and 27, and the illumination light transmitted from the second illumination 27 through the absorber 11c (and the core wrap sheet 11s). Adjust as follows. At this time, the illumination light transmitted through the absorber 11c from the second illumination 27 has a small amount of light when transmitted through the absorber 11c. Therefore, if the amount of light of the first illumination 23 is too large, May be canceled by the illumination light from the illumination 23 and cannot be detected by the first camera 21. For this reason, in the case of the first embodiment, the light amount of the first illumination 23 is smaller than the light amount of the second illumination 27. The ratio of the amount of light of the first and

second illuminations

23 and 27 differs depending on the thickness and material of the inspection object that is the absorber 11c in the first embodiment, but the optimum ratio is determined by experiments or the like. Is preferred. However, the first illumination 23 is required to illuminate with a light amount that allows the first camera 21 to detect the presence or absence of foreign matter on the first surface F1 of the absorber 11c. The ratio of the amount of light of the first and

second illuminations

23 and 27 that satisfies these conditions is 1: 4 in the first embodiment, and by adopting this ratio, the outer shape determination step, surface foreign matter, which will be described later, is performed. All of the detection step and the internal foreign matter detection step can be performed without delay.

In the first embodiment, when the illuminance on the second surface F2 of the absorber 11c is adjusted so that the illuminance on the second surface F2 of the absorber 11c is 2000 lux to 6000 lux, the contour line of the absorber 11c is set. It is preferable because it is possible to capture a clear image without causing whiteout and the illumination light from the second illumination 27 can pass through the absorber 11c. Accordingly, when the illuminance on the first surface F1 of the absorber 11c is adjusted to be 500 lux to 1500 lux, the light amount of the first illumination 23 is absorbed by the absorber 11c from the second illumination 27. This is preferable because the foreign light on the first surface F1 of the absorber 11c can also be detected in the surface foreign matter detection step described later without canceling the illumination light transmitted through the surface.

In the inspection process of the first embodiment, the photographing process is performed after the light intensity adjustment process. In the photographing process, the first and

second cameras

21 and 25 are used to photograph the first surface F1 and the second surface F2 of the absorber 11c so as to include the outer shape of the absorber 11c.

The image acquired by the first camera 21 includes the illumination light from the first illumination 23 reflected by the first surface F1 of the absorber 11c and the illumination light from the second illumination 27 as the absorber. It is mapped by the illumination light transmitted through 11c. On the other hand, the image acquired by the second camera 25 is mapped by the illumination light reflected from the second surface F2 of the absorber 11c by the illumination light from the second illumination 27.

In the first embodiment, when the first and

second cameras

21 and 25 receive control signals for starting and stopping shooting from the control device 31, shooting by the first and

second cameras

21 and 25 is performed. Start and end. In another embodiment, the first and

second cameras

21 and 25 manually start and end shooting. Thereby, the image of the 1st and 2nd surface F1, F2 of each absorber 11c which followed the conveyance direction MD of the absorber 11c can be acquired.

In the inspection process of the first embodiment, the outer shape determination process is performed after the photographing process is completed. In the outer shape determination step, it is determined from the images acquired by the first and

second cameras

21 and 25 in the photographing step whether or not the outer shape of the absorber 11c is acceptable. Determination of the outer shape of the absorber 11c is performed using a preset virtual reference frame 41 as shown in FIG. These reference frames 41 are applied to a predetermined portion of the image acquired in the above photographing process from the transport distance data of the absorber 11c transmitted from the rotary encoder 29e to the control device 31. The shape is set so as to be separated from the outline of the absorber 11c by an allowable error. In addition, in FIG. 4, although a mode that the external shape of the conveyance direction MD downstream part of the absorber 11c is shown is shown, naturally the external shape of the conveyance direction MD upstream part of the absorber is also inspected similarly. Can do. Furthermore, it should be noted that the illustration of the core wrap sheet 11s is omitted in FIG.

Specifically, the reference frame 41 includes an outer reference frame 41o arranged outside the outline of the absorber 11c and an inner reference frame 41i arranged inside the outline of the absorber 11c. In the outer shape determination step, when a part of the absorber 11c is contained in the outer reference frame 41o, it is determined that the outer shape of the absorber 11c is not acceptable. In the outer shape determination step, if there is a part of the inner reference frame 41i that does not contain the absorber 11c, it is determined that the outer shape of the absorber 11c is not acceptable. According to such a judgment criterion, not only the outer shape of the absorber 11c itself but also the case where the absorber 11c is turned during transportation, torn due to the tension of transportation, or torn, These can be detected.

In the first embodiment, the reference frame 41 is formed at the center portion in the longitudinal direction LD of the absorber 11c, and the shape of the outer reference frame 41o for inspecting the outer shape of the foot portion having a small short direction SD dimension is: The shape of the outer reference frame 41o and the inner reference frame 41i for inspecting the outer shape of the end portion in the longitudinal direction LD of the other absorber 11c is rectangular. . As the shape of each of the reference frames 41, an arbitrary shape can be selected in consideration of the outer shape of the desired absorber 11c and an allowable error from the outer shape.

Moreover, the control apparatus 31 which has received the conveyance distance data of the absorber 11c from the rotary encoder 29e as described above uses this conveyance distance data to detect a positional deviation from the predetermined arrangement of each absorber 11c. You can also Specifically, the control device 31 can detect how much the interval between adjacent absorbers 11c differs from the predetermined product length Lp.

In the first embodiment, both of the images acquired by the first and

second cameras

21 and 25 are used in the outer shape determination step. However, in another embodiment, the first and

second cameras

21 and 25 are used. The outer shape determination step is performed using any one of the images acquired in the step S25. When using the image acquired by the 1st camera 21, as mentioned above, the illumination light which the illumination light from the 1st illumination 23 reflected on the 1st surface F1 of the absorber 11c, and the 2nd illumination 27 The outer shape of the absorber 11c is determined using an image obtained by mapping the illumination light from the illumination light transmitted through the absorber 11c. Moreover, when using the image acquired by the 2nd camera 25, the illumination light from the 2nd illumination 27 uses the image mapped by the illumination light reflected by the 2nd surface F2 of the absorber 11c, The outer shape of the absorber 11c is determined. As described above, in the present invention, it can be understood that the outer shape determination step can be performed using both or any one of the images acquired by the first and

second cameras

21 and 25.

Furthermore, in the inspection process of the first embodiment, a surface foreign matter detection process is performed after the imaging process. In the surface foreign matter detection step, the presence or absence of foreign matter on at least the first and second surfaces F1 and F2 of the absorber 11c is detected from the images acquired by the first and

second cameras

21 and 25 in the photographing step. In the surface foreign matter detection step, images acquired by the first and

second cameras

21 and 25 are analyzed by the control device 31. Consider a case where a foreign substance that is a lump of adhesive used in an upstream process is attached to the first surface F1 of the absorbent body 11c. In the case of this example, the first camera 21 binarizes an image obtained by capturing the portion of the absorber 11c to which the foreign substance is attached, according to a predetermined threshold value such as luminance or brightness in the first embodiment ( It is possible to detect a foreign object by confirming whether or not there is a black portion in the binarized image. In this case, threshold values of values such as luminance and lightness when binarizing an image are determined according to a foreign substance that is supposed to adhere to the inspection object that is the absorber 11c in the first embodiment. be able to.

In addition, although the surface foreign material detection process of 1st embodiment demonstrated as an example the process of detecting the foreign material adhering on the 1st surface F1, it is 2nd also about the foreign material adhering on the 2nd surface F2. It can detect by performing the same analysis using the image acquired by the camera 25.

Further, in the present disclosure, “foreign matter” refers to all items that are not planned to be mixed in the absorbent article to be manufactured, and is deposited on hair and manufacturing equipment other than the lump of adhesive exemplified above. Examples include lump of cotton dust and non-woven fabric pieces generated from troubles in other processes.

The illumination light from the first and

second illuminations

23 and 27 depends on the amount of illumination light, the basis weight and thickness of the absorber 11c, etc., but the first and second surfaces F1 of the absorber 11c. The light is reflected not only on the surface of F2, but also at a portion that enters the absorber 11c in the thickness direction from the first and second surfaces F1 and F2 of the absorber 11c to some extent. Therefore, the image mapped by the illumination light reflected by the first and second surfaces F1 and F2 of the absorber 11c also maps the illumination light by such reflection together. As a result, not only on the first and second surfaces F1 and F2 of the absorber 11c but also to some extent inside the thickness direction of the absorber 11c from the first and second surfaces F1 and F2 of the absorber 11c. The foreign matter present at the location is also detected together. However, the absorber 11c has a certain thickness, and it is difficult to detect the foreign matter existing inside the absorber 11c up to the central portion in the thickness direction of the absorber 11c only by the reflected illumination light. Therefore, in order to detect the foreign matter existing inside the absorber 11c, an internal foreign matter detection process described below is required.

Furthermore, in the inspection process of the first embodiment, an internal foreign matter detection process is performed after the imaging process. In the internal foreign matter detection step, the presence or absence of foreign matter inside the absorber 11c is detected from the image acquired by the first camera 21 in the photographing step. In the internal foreign matter detection step, the control device 31 analyzes the image acquired by the first camera 21.

The specific image analysis method in the internal foreign matter detection step is the same as that in the surface foreign matter detection step. The image acquired by the first camera 21 includes illumination light from the first illumination 23 reflected by the first surface F1 of the absorber 11c and illumination from the second illumination 27 as described above. The light is mapped by the illumination light transmitted through the absorber 11c. Therefore, for example, when the image acquired by the first camera 21 is binarized as in the example of the analysis method of the surface foreign matter detection step described above, the foreign matter mixed inside the absorber 11c The illumination light transmitted through the absorber 11c from the second illumination 27 is blocked. As a result, the portion where the foreign matter is present appears as a shadow in the binarized image, whereby the presence of the foreign matter can be detected.

In the inspection process, a discharge process is performed after the above-described outer shape determination process, surface foreign object detection process, and internal foreign object detection process. In the discharging step, the absorber 11c in which the outer shape defect and / or the foreign object defect is detected is discharged from the conveyance path of the absorber 11c.

The discharging process is performed after the composite continuous body 11 is cut so as to form individual absorbent bodies 11c by a discharging device (not shown) provided in the subsequent process of the inspection unit 20. The discharging device includes an absorber 11c having a defective outer shape that is determined to have an unacceptable outer shape of the absorber 11c, and an absorber 11c having a foreign object in which foreign matters are mixed on the surface and / or inside of the absorber 11c. This is a device that excludes the defective absorber 11c from the conveyance path of the absorber 11c in accordance with a discharge control signal transmitted from the control device 31 when it passes through the discharge device. The discharge device is, for example, an air blow device that blows off a defective absorber with high-pressure air, or a pusher that pushes out a defective absorber from the side surface of the conveyance path. In the first embodiment, the discharging device is controlled by the control device 31 so that the defective absorber is discharged from the conveyance path of the absorber 11c when the defective absorber passes through the discharging device.

From this, the effect of the method for manufacturing the absorbent article according to the first embodiment will be described.

(1) In the inspection unit 20 according to the first embodiment, the presence or absence of foreign matter on the second surface F2 of the absorber 11c and inside the absorber 11c is determined using an image acquired by one second camera 25. Since it can test | inspect in parallel, compared with the test | inspection unit 100 of FIG. 6, an inspection process can be performed with few cameras and the number of illuminations. Thereby, since the camera and the illumination can be installed in one place, the installation space for the camera and the illumination can be saved, and the camera and the illumination can be centrally managed. As a result, the inspection unit 20 can be simplified, and the maintenance of these cameras and lighting can be facilitated. In addition, the inspection of the outer shape of the absorber 11c and the presence or absence of foreign matter can be performed in parallel with less equipment cost.

(2) In the first embodiment, the first and

second cameras

21 and 25 are line cameras, as compared with an area camera that requires a certain imaging range of the absorber 11c (particularly in the transport direction MD). Thus, the

cameras

21 and 25 can be installed in a smaller space. As described above, the transport device 29 includes components that support the absorber 11c such as a conveyor belt in order to enable photographing from both the first surface F1 and the second surface F2 of the absorber 11c. Since it does not have, the conveyance of the absorber 11c becomes unstable. For example, the absorber 11c vibrates in the short direction SD of the absorber 11c, and the acquired image is not sufficiently clear and is precisely inspected. May become difficult. However, in the first embodiment, the first and

second cameras

21 and 25 are line cameras, and the imaging region in the transport direction MD of the absorber 11c is very small. In this embodiment, the distance Lt (between nip rolls) can be reduced. As a result, it is preferable because the absorber 11c can be stably transported, and thus a precise inspection can be performed.

(3) The first embodiment includes a discharging step of discharging the absorber 11c in which the outer shape defect and / or the foreign object defect are detected in the outer shape determination process, the surface foreign object detection process, and the internal foreign object detection process. Thereby, it is possible to prevent the absorbent article including the absorbent body 11c that has been determined to be defective in outer shape and / or foreign matter from being shipped as a product before the step of pasting with other members, which is preferable.

In the camera placement step, the distance (Lc) between the first camera 21 and the second camera 25 in the transport direction MD of the absorber 11c may be shorter than the above-described transport repeat unit length of the absorber 11c. it can. Thereby, the first camera 21 and the second camera 25 can simultaneously photograph at least a part of the conveyance repeating unit of the same absorber 11c. This makes it easy to recognize the same transport repeat unit from the images taken by the first and

second cameras

21 and 25, and thus makes it easy to recognize the same transport repeat unit in each image.

Furthermore, in the camera placement step, the first and

second cameras

21 and 25 are set such that the distance Lc between the first and

second cameras

21 and 25 in the conveyance direction MD of the absorber 11c is zero. It can also be arranged on one straight line orthogonal to the conveyance direction MD of the absorber 11c. Thereby, since the installation space of the 1st and

2nd cameras

21 and 25 does not spread in the conveyance direction MD of the absorber 11c, the installation space of the 1st and

2nd cameras

21 and 25 and by extension, the inspection unit 20 is reduced. It can be further reduced.

As described above, when the first and

second cameras

21 and 25 are arranged on a straight line orthogonal to the conveyance direction MD of the absorber 11c, the optical axis OA of the first illumination 23 and the absorber 11c are further added. The intersection point P1 of the first surface F1 and the intersection point P2 of the optical axis OA of the second illumination 27 and the second surface F2 of the absorber 11c connect the first camera 21 and the second camera 25. In the illumination arrangement step, the first and

second illuminations

23 and 27 can be arranged so as to be positioned on a straight line. Thereby, the imaging area of the

cameras

21 and 25 on the first and second surfaces F1 and F2 of the absorber 11c is aligned with the optical axis OA of the

illuminations

23 and 27, thereby making the imaging area most efficient. Can be illuminated.

In the present disclosure, the straight line connecting the first camera 21 and the second camera 25 indicates a straight line connecting the image sensors (imaging elements) of the

cameras

21 and 25. Note that since there is a certain size, the straight line connecting the first camera 21 and the second camera 25 has a certain width.

In the present disclosure, the “illumination optical axis” is a virtual light beam that is representative of the luminous flux emitted from the first and

second illuminations

23 and 27, that is, the central portion of the illuminated portion of the illumination. As a starting point, an imaginary line extending in the direction in which the light beam emitted from the

illuminations

23 and 27 travels is assumed.

(Second embodiment)
Hereafter, the method to manufacture the absorbent article which concerns on 2nd embodiment of this invention is demonstrated, referring drawings. Regarding the second embodiment, differences from the first embodiment will be mainly described. In addition, the configuration of the first embodiment other than the differences from the second embodiment can be applied to the second embodiment, and those skilled in the art can arbitrarily combine these configurations within the obvious range. Please note that. In the first embodiment, the presence or absence of foreign matter on the first and second surfaces F1 and F2 of the absorber 11c is inspected using the two

cameras

21 and 25. In the second embodiment, however, Two cameras 21 are used to inspect for the presence of foreign matter only on the first surface F1 of the absorber 11c.

Referring to FIG. 5, unlike the inspection unit of the first embodiment, the inspection unit 20 of the first embodiment is not provided with the second camera 25 that images the second surface F2 of the absorber 11c. . In the second embodiment, the second illumination 27 is different from the second illumination in the first embodiment. The second illumination 27 is located on the second surface F2 side of the absorber 11c across the absorber 11c. Are arranged in front of the camera 21. Thereby, the illumination light that has passed through the absorber 11 c from the second illumination 27 can easily reach the first camera 21. The configuration of the inspection unit 20 in the other second embodiment is the same as the configuration of the inspection unit in the first embodiment.

Hereafter, in the second embodiment, a case where an inspection process is performed using the inspection unit 20 will be described with reference to FIG.

In the inspection process of the second embodiment, first, a camera arrangement process and an illumination arrangement process are performed. In the camera placement step, the first camera 21 is placed on the first face F1 side of the absorber 11c so as to photograph the first face F1. In the illumination arrangement step, the first illumination 23 and the second of the absorber 11c are provided on the first surface F1 side of the absorber 11c so as to illuminate the region of the absorber 11c photographed by the first camera 21. The second illumination 27 is arranged on the surface F2 side as shown in FIG.

In the inspection process of the second embodiment, the light amount adjustment process is performed after the camera arrangement process and the illumination arrangement process. In the light amount adjustment step, the light amounts of the first and

second illuminations

23 and 27 are adjusted so that the first camera 21 can sense the illumination light transmitted through the absorber 11c from the second illumination 27.

In the inspection process of the second embodiment, the photographing process is performed after the light intensity adjustment process. In the imaging step, the first camera F is used to image the first surface F1 of the absorber 11c so as to include the outer shape of the absorber 11c.

In the inspection process of the second embodiment, the outer shape determination process is performed after the photographing process is completed. In the outer shape determination step, it is determined whether the outer shape of the absorber 11c is acceptable from the image acquired by the first camera 21 in the photographing step.

In the inspection process of the second embodiment, a surface foreign matter detection process is further performed after the imaging process. In the surface foreign matter detection step, the presence or absence of foreign matter on at least the first surface F1 of the absorber 11c is detected from the image acquired by the first camera 21 in the photographing step.

In the inspection process of the second embodiment, an internal foreign matter detection process is further performed after the imaging process. In the internal foreign matter detection step, the presence or absence of foreign matter inside the absorber 11c is detected from the image acquired by the first camera 21 in the photographing step.

And in the inspection process of the second embodiment, the discharge process is performed after the above-described outer shape determination process, surface foreign object detection process and internal foreign object detection process. In the discharging step, the absorber 11c in which the outer shape defect and / or the foreign object defect is detected is discharged from the conveyance path of the absorber 11c.

Details of the camera placement process, illumination placement process, light quantity adjustment process, photographing process, external shape judgment process, surface foreign matter detection process, internal foreign matter detection process and discharge process performed in the inspection process of the second embodiment are as follows. The second camera is not arranged in the process, and only the first surface F1 of the absorber 11c is photographed using the first camera 21 in the photographing process, and the outer shape determination process, the surface foreign object detection process, and the internal foreign object detection process. However, since it is the same as the inspection process of the first embodiment except that only the image acquired from the first camera 21 is used, the description is omitted.

The manufacturing method which concerns on 2nd embodiment is the back side of the absorbent article which the 2nd surface F2 of the absorber 11c manufactures, or another which interrupts | blocks the 2nd surface F2 visually on the 2nd surface F2. This is effective particularly when there is no need to inspect the presence or absence of foreign matter on the second surface F2 of the absorber 11c. That is, compared with the first embodiment, the number of cameras to be used can be reduced by one, so that the inspection unit 20 can be further simplified, and the maintenance management of these cameras and lighting is further facilitated. be able to. In addition, the inspection of the outer shape of the absorber 11c and the presence or absence of foreign matter can be performed in parallel with a smaller equipment introduction cost.

In the above-described embodiment, the first and

second cameras

21 and 25 are line cameras. However, in another embodiment, the first and

second cameras

21 and 25 are area cameras that capture a fixed rectangular area. It is. In this case, each of the conveyed absorbers 11c is photographed one or more times, and the entire images of the first and second surfaces F1 and F2 are acquired so as to include the outer shape of each absorber 11c. In addition, when image | photographing several times about one absorber 11c, it is preferable to image | photograph the whole of each absorber 11c if it images so that these images may overlap in the conveyance direction MD of the absorber 11c. The first and

second cameras

21 and 25 are photographed at a predetermined timing based on the transport distance of the absorber 11c and the number of times of photographing of each absorber 11c transmitted from the rotary encoder 29e. Is called.

In the above description, the first and

second cameras

21 and 25 are directed perpendicular to the conveyance direction MD of the absorber 11c, but the present invention is not limited to this. The first and

second cameras

21 and 25 are arranged in the conveying direction MD of the constituent members depending on the space restrictions of the facilities for installing them and the three-dimensional shape of the inspection object that is the absorber 11c in the above-described embodiment. Can be oriented in any direction that intersects.

In the above-described embodiment, the foreign matter is detected by binarizing the images acquired by the first and

second cameras

21 and 25 in the surface foreign matter detection step and the internal foreign matter detection step. It is not limited to the image analysis method. Any known image analysis method can be used to detect foreign objects from the images acquired by the first and

second cameras

21 and 25. These image analysis methods can be selected appropriately depending on the shape and color tone of a foreign object to be detected.

In the above-described embodiment, the outer shape determination process, the surface foreign object detection process, and the internal foreign object detection process include the discharging process of discharging the absorber 11c in which the outer shape defect and / or the foreign object defect is detected. However, the present invention is not limited to this. Not. For example, one or two of the outer shape determination process, the surface foreign object detection process, and the internal foreign object detection process, depending on the structure of the absorbent article to be manufactured and the type of the inspection object that is the absorber 11c in the above-described embodiment. Only the absorber 11c in which a defect is detected in only the process may be discharged. Or the absorber 11c by which the external shape defect and / or the foreign material defect were detected may not be discharged depending on the degree of the defect.

In the above-described embodiment, the first and

second illuminations

23 and 27 have a bar shape having a longitudinal direction in a direction intersecting the transport direction MD, 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 appropriately illuminate the imaging region.

In the above-described embodiment, the first and

second illuminations

23 and 27 are LED illuminations, but may be other types of light sources such as a fluorescent lamp and a mercury lamp.

Furthermore, in the above-mentioned embodiment, the 1st and

2nd illuminations

23 and 27 are arrange | positioned rather than the 1st and

2nd cameras

21 and 25, respectively in the upstream and downstream of the conveyance direction MD of the absorber 11c. With two lights. However, in order to increase the amount of illumination light and / or equalize the amount of light in the imaging region, each of the first and

second illuminations

23 and 27 is provided with one or more illuminations other than these illuminations. And on the upstream side, the downstream side, or both the upstream side and the downstream side of the

second cameras

21 and 25.

In the above-described embodiment, the components of the inspection unit 20 such as the first and

second cameras

21 and 25 and the first and

second lights

23 and 27 are controlled by one control device 31. Each of these components of the inspection unit 20 may be provided with a control device. Further, the control device 31 may be automatically operated according to a program created in advance, or may be manually operated with respect to some control such as adjustment of the light amount of the first and

second illuminations

23 and 27. Good.

In the above-described embodiment, the control device 31 is a PLC, but it may be a computer or the like that can perform the same operation as the PLC.

In the above-described embodiment, the inspection object is the absorber 11c covered with the core wrap sheet 11s, but the present invention is not limited to this. For example, the inspection object may be a member to which a web having a thickness such as a loop material for fixing hook tape in a cushion sheet or a hook-and-loop fastener is bonded, and absorbs disposable diapers, sanitary napkins, tampons, etc. The article itself may be used.

For example, as a modified embodiment of the first embodiment, a case where the inspection object is the disposable diaper 1 itself shown in FIGS. 1A and 1B can be considered. In this modified embodiment, the inspection process is performed so that the top sheet 3 of the disposable diaper 1 becomes the second surface F2 of the disposable diaper 1 and the back sheet 5 of the disposable diaper 1 becomes the first surface F1 of the disposable diaper 1. Preferably it is done. Thereby, in the disposable diaper 1, in particular, the foreign matter inspection on the surface of the top sheet 3 that touches the skin surface of the wearer is performed by the illumination from the second illumination 27 having a larger amount of light than the first illumination 23 in the surface foreign matter detection step. By using an image acquired by the second camera in which the light is mapped by the illumination light reflected by the top sheet 3, it can be performed with higher accuracy. In this modified embodiment, the test object may be another type of absorbent article such as a sanitary napkin having a top sheet, a back sheet, and an absorbent body.

In the above-described embodiment, each of the absorbers 11c, which are inspection objects, is intermittently conveyed at intervals of the conveyance repetition unit length while being covered with the core wrap sheet 11s, but the present invention is limited to this. It is not a thing. The inspection object in the present invention may be, for example, a continuous body of absorbent bodies that are continuously formed in the transport direction and are cut at predetermined intervals to form the respective absorbent bodies 11c. Good. In this case, the said predetermined space | interval which cut | disconnects the continuous body of the said absorber becomes a conveyance repetition unit length.

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

1 Disposable diaper (absorbent article)
11c Absorber (inspection object)
21 1st camera 23 1st illumination 25 2nd camera 27 2nd illumination F1 1st surface F2 2nd surface MD Conveyance direction

Claims

External inspection and foreign object inspection of an inspection object, which is an absorbent article itself or a constituent member of the absorbent article, having a first surface and a second surface opposite to the first surface, A method of manufacturing an absorbent article including an inspection process performed in parallel during the transportation of an object,
The inspection step is
A camera arrangement step of arranging a first camera on the first surface side of the inspection object so as to photograph the first surface;
The first illumination on the first surface side of the inspection object and the second surface side of the inspection object so as to illuminate the region of the inspection object photographed by the first camera An illumination arrangement step of arranging the second illumination;
A light amount adjustment step of adjusting the light amounts of the first illumination and the second illumination so that the first camera can sense the illumination light transmitted through the inspection object from the second illumination;
An imaging step of imaging the first surface of the inspection object so as to include the outer shape of the inspection object using the first camera;
From the image acquired by the first camera in the photographing step, an outer shape determination step for determining whether or not the outer shape of the inspection object is acceptable;
From the image acquired by the first camera in the photographing step, a surface foreign matter detection step of detecting the presence or absence of foreign matter on at least the first surface of the inspection object;
From the image acquired by the first camera in the photographing step, an internal foreign matter detection step for detecting the presence or absence of foreign matter inside the inspection object;
including,
A method of manufacturing an absorbent article.
External inspection and foreign object inspection of an inspection object, which is an absorbent article itself or a constituent member of the absorbent article, having a first surface and a second surface opposite to the first surface, A method of manufacturing an absorbent article including an inspection process performed in parallel during the transportation of an object,
The inspection step is
The first camera is photographed so as to photograph the first surface on the first surface side of the inspection object, and the second surface is photographed on the second surface side of the inspection object. A camera placement step of placing a second camera as
On the first surface side of the inspection object, first illumination for illuminating a region of the inspection object photographed by the first camera, and on the second surface side of the inspection object, An illumination arrangement step of arranging a second illumination that illuminates the region of the inspection object imaged by the second camera;
A light amount adjustment step of adjusting the light amounts of the first illumination and the second illumination so that the first camera can sense the illumination light transmitted through the inspection object from the second illumination;
Using the first camera and the second camera, an imaging step of photographing the first surface and the second surface of the inspection object so as to include the outer shape of the inspection object;
An outer shape determination step for determining whether or not the outer shape of the inspection object is acceptable from either one or both of the images acquired by the first camera and the second camera in the photographing step;
Surface foreign matter detection for detecting the presence or absence of foreign matter on at least the first surface and the second surface of the inspection object from images acquired by the first camera and the second camera in the photographing step. Process,
From the image acquired by the first camera in the photographing step, an internal foreign matter detection step for detecting the presence or absence of foreign matter inside the inspection object;
including,
A method of manufacturing an absorbent article.
In the camera placement step, the distance between the first camera and the second camera in the conveyance direction of the inspection object is made shorter than the conveyance repetition unit length of the inspection object.
The method of claim 2.
In the camera arrangement step, the first camera and the second camera are arranged on one straight line orthogonal to the conveyance direction of the inspection object.
The method of claim 2.
The intersection of the optical axis of the first illumination and the first surface of the inspection object and the intersection of the optical axis of the second illumination and the second surface of the inspection object are the first Located on a straight line connecting the second camera and the second camera,
The method of claim 4.
The inspection object is the absorbent article itself,
The absorbent article includes a liquid-permeable top sheet on the second surface, a liquid-impervious back sheet on the first surface, and a liquid absorbent interposed between the top sheet and the back sheet. Having a sex absorbent,
The method according to any one of claims 2 to 5.
The second camera is a line camera;
The method according to any one of claims 2 to 6.
The first camera is a line camera;
The method according to any one of claims 1 to 7.
The light quantity of the first illumination is smaller than the light quantity of the second illumination.
The method according to any one of claims 1 to 8.
Each of said 1st illumination and said 2nd illumination is a shape which has a longitudinal direction in the direction which cross | intersects the conveyance direction of the said test target object,
The dimension of the first illumination and the second illumination in the direction intersecting the conveyance direction of the inspection object is larger than the dimension in a direction intersecting the conveyance direction of the inspection object,
The method according to any one of claims 1 to 9.
The first illumination and the second illumination are LED illuminations,
The method according to any one of claims 1 to 10.
Furthermore, the step of discharging the inspection object determined to be unacceptable in the outer shape determination step of the inspection object,
The method according to any one of claims 1 to 11.
Furthermore, the step of discharging the inspection object in which the foreign object is detected in the surface foreign object detection process of the inspection object,
The method according to any one of claims 1 to 12.
Furthermore, the step of discharging the inspection object in which the foreign object is detected in the internal foreign object detection process of the inspection object,
The method according to any one of claims 1 to 13.
The inspection object is a liquid-absorbent absorber used for manufacturing the absorbent article,
The plurality of absorbers are conveyed in a state of being covered by a continuous sheet that is continuous in the conveying direction of the absorber.
The method according to any one of claims 1 to 14.