JP2018086112A - Method and apparatus for inspection of opening sheet, method for manufacturing opening sheet and method for manufacturing absorbent article - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method that can stably inspect an opening state of the sheet without being influenced by image irregularities due to lighting.SOLUTION: A two-dimensional laser displacement meter 11 is arranged in one surface 20a side in an opening sheet 20 having multiple openings 21a, the two-dimensional laser displacement meter 11 is used under the condition where a reference surface table 15 is arranged in the other surface 20b side, and thereby a laser beam is applied toward the opening sheet 20 to receive the reflected light. A distance D from the reflection position of the laser beam to a light receiving unit 12b in the two-dimensional laser displacement meter 11 is measured. The goodness/badness of the openings 21a is determined based on the value of the measured distance D.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an inspection method and an inspection apparatus for an apertured sheet. Moreover, this invention relates to the manufacturing method of an apertured sheet, and the manufacturing method of an absorbent article.

  Various absorbent articles such as disposable diapers and sanitary napkins generally include a surface sheet that is a member that comes into contact with the skin of the wearer. Since the surface sheet is required to be liquid permeable, a nonwoven fabric is generally used as the surface sheet. A technique for forming a plurality of apertures in a nonwoven fabric for the purpose of further increasing the liquid permeability of the nonwoven fabric is known.

  When forming an opening in a nonwoven fabric, if the opening is not formed reliably, the desired liquid permeability is not achieved, so the nonwoven fabric is formed in the nonwoven fabric prior to incorporation into the absorbent article. It is advantageous to check whether the apertures are as designed. As such an inspection method, for example, a technique described in Patent Document 1 is known. In the same document, a region of the nonwoven fabric in which openings are formed is imaged to generate plane image data, a binary image is generated based on the data of the plane image, and based on the binarized image An inspection method for determining whether there is an abnormality in opening is described.

JP 2013-85759 A

  However, in the inspection method described in Patent Document 1, when the data of the planar image is binarized, there is a possibility that the unevenness of the texture of the nonwoven fabric is erroneously detected as an opening. Moreover, there is a risk that it is determined that no aperture is formed by erroneously detecting fibers remaining thinly in the aperture or fibers formed into a film due to poor aperture of a nonwoven fabric or a film. Furthermore, the deterioration of the illumination that illuminates the inspection object, uneven illuminance, and the like also cause erroneous detection. For these reasons, it is not easy to stably inspect the open state with an inspection method based on an image obtained by imaging.

  Accordingly, an object of the present invention is to improve the inspection method of the opening in a sheet having a plurality of openings, and more specifically, to provide a method capable of performing the inspection of the opening more stably than the conventional method. is there.

In the present invention, a two-dimensional laser displacement meter is disposed on one surface side of a sheet having a plurality of apertures, and the two-dimensional laser displacement meter is used to irradiate a laser beam toward the sheet and to reflect the reflected light. Receiving light; and
Measuring the distance from the reflection position of the laser beam to the light receiving part in the two-dimensional laser displacement meter,
And determining the quality of the aperture based on the measured distance value, and providing a method for inspecting the aperture sheet.

Further, the present invention is a two-dimensional laser displacement meter disposed on one surface side of a sheet having a plurality of apertures,
And a determination processing unit that determines the quality of the aperture based on the imaging data transmitted from the two-dimensional laser displacement meter.

Furthermore, the present invention comprises a step of forming a plurality of apertures in the original sheet while conveying the elongated original sheet in one direction;
A two-dimensional laser displacement meter is disposed on one surface side of a sheet having a plurality of apertures, and the two-dimensional laser displacement meter is used to direct the laser beam to the sheet in a conveying state so as to intersect the conveying direction. And receiving the reflected light in a linear manner,
Measuring the distance from the reflection position of the laser beam to the light receiving portion in the two-dimensional laser displacement meter over the surface direction of the sheet;
And a step of determining the quality of the aperture based on the measured distance value.

Furthermore, the present invention comprises a step of forming a plurality of apertures in the original sheet while conveying the elongated original sheet in one direction;
A process for producing an absorbent article using a sheet having a plurality of apertures and another member constituting the absorbent article,
The manufacturing method is
A two-dimensional laser displacement meter is disposed on one surface side of the sheet having a plurality of apertures, and the two-dimensional laser displacement meter is used to direct the laser so as to cross the conveyance direction toward the sheet in the conveyance state. Irradiating light linearly and receiving the reflected light;
Measuring the distance from the reflection position of the laser beam to the light receiving portion in the two-dimensional laser displacement meter over the surface direction of the sheet;
And a step of determining the quality of the opening based on the measured distance value.

  According to the present invention, it is possible to stably inspect the open state without being affected by image unevenness caused by illumination or the like. Further, according to the present invention, it is possible to detect burrs or the like that may be formed unintentionally around the opening portion of the sheet.

FIG. 1 is a schematic view showing an embodiment of an inspection apparatus for an apertured sheet according to the present invention. FIG. 2 is a schematic plan view showing an example of a sheet that is an object of the inspection method for a perforated sheet of the present invention. 3 (a) and 3 (b) are graphs showing the measurement results using the inspection apparatus for apertured sheets of the present invention, respectively. FIG. 4 is a schematic view showing an embodiment of the production apparatus of the present invention. FIG. 5 is a schematic diagram showing a holed state of the hole-sheet obtained using the manufacturing apparatus shown in FIG. FIG. 6 is a schematic diagram showing a method of correcting the inspection position when the sheet is meandering when the apertured sheet is manufactured using the manufacturing apparatus shown in FIG.

  The present invention will be described below based on preferred embodiments with reference to the drawings. The present invention relates to inspecting the quality of the openings in a sheet having a plurality of openings. The opening formed in the sheet is a through hole extending in the thickness direction of the sheet. The inspection of the quality of the opening is to check whether or not the opening is formed as designed. If the outline of the aperture is not clear and the shape is as designed, or if there are a large number of sheet fibers in the aperture and a complete through hole is not formed, If there is a flake in which the constituent fibers of the sheet are formed into a film and a complete through hole is not formed, it is determined that the hole is not formed properly. Moreover, even if the through hole is formed, a large number of fibers are present in the opening, or a thin piece in which the fiber is formed into a film exists, and the opening is not shaped as designed. Also in this case, it is determined that the hole is not formed properly.

  There are no particular limitations on the size and shape of the apertures formed in the sheet, and the arrangement pattern, and the apertures can be appropriately selected according to the specific application of the sheet having apertures. There is no particular limitation on the upper limit value of the area of one opening, and the inspection of the quality of the opening becomes easier as the area increases. Moreover, there is no restriction | limiting in particular also in the upper limit of the distance between adjacent openings.

  There is no particular limitation on the type of sheet to be inspected, and various types of sheets known so far can be inspected. Examples of the sheet to be inspected include a film and a nonwoven fabric. Examples of the nonwoven fabric include spunbond nonwoven fabric, air-through nonwoven fabric, meltblown nonwoven fabric, spunlace nonwoven fabric, resin bond nonwoven fabric, and needle punched nonwoven fabric. The sheet may have a multilayer structure in which these materials are arbitrarily combined, or may have a single layer structure. Further, the sheet to be inspected in the present invention may be a laminate of a nonwoven fabric and a film. In that case, it is necessary for the laminate to have openings that penetrate both the nonwoven fabric portion and the film portion of the laminate. In the case where the sheet to be inspected is a non-woven fabric, there is an additional advantage that the open state can be stably inspected without being affected by the unevenness of the image due to the unevenness of the texture.

  FIG. 1 shows an embodiment of the apparatus of the present invention used for inspection of an apertured sheet. The inspection apparatus 10 of the present invention is configured by arranging a two-dimensional laser displacement meter 11 on the first surface 20a side which is one surface of an apertured sheet 20 having a plurality of apertures to be inspected. Yes. The two-dimensional laser displacement meter 11 includes a sensor head 12 and a controller 13. Both are connected via a control line 14. Further, the inspection apparatus 10 is configured by arranging a reference surface table 15 on the second surface 20b side which is the other surface of the apertured sheet 20.

  The sensor head 12 has a structure in which a laser beam irradiation unit 12a and a light receiving unit 12b are built in one unit. Specifically, the laser beam spread in a band shape by an optical system (not shown) such as a cylindrical lens provided in the laser beam irradiation unit 12a is linearly irradiated to the object to be inspected, and the surface of the object The reflected light diffused and reflected at is imaged on a light receiving element (not shown) provided in the light receiving section 12b. The imaging data is transmitted to the controller 13 through the control line 14. Based on the imaging data, the controller 13 obtains the position and shape of the object and their temporal changes by calculation.

  The laser light emitted from the irradiation part 12a of the sensor head 12 is linear. By irradiating the laser beam linearly, the shape and displacement of the object can be detected two-dimensionally in the thickness direction (Z direction in FIG. 1) and in the width direction (X direction in FIG. 2). The wavelength of the laser beam may be, for example, the visible wavelength region, or may be outside the visible wavelength region, for example, the infrared wavelength region or the ultraviolet wavelength region.

  The reference surface table 15 is used as a reflector that reflects the laser light transmitted through the apertures provided in the aperture sheet 20. From this point of view, the reflection surface of the reference surface 15 for the laser beam, that is, the reference surface 15a that is the surface facing the second surface 20b of the aperture sheet 20 is in a surface state suitable for the reflection of the laser beam. Preferably it is.

  The reference surface table 15 is preferably arranged so that the reference surface 15 a is parallel to the surfaces 20 a and 20 b of the apertured sheet 20. The width of the reference surface 15a in the reference surface 15a in the direction corresponding to the width direction of the aperture sheet 20 is larger than the width of the laser beam irradiated from the sensor head 12 of the two-dimensional laser displacement meter 11, and the aperture is opened. It is preferable to have a size larger than the width of the sheet.

  In order to determine the quality of the hole in the hole sheet 20 using the inspection apparatus 10 having the configuration shown in FIG. 1, for example, the following procedure may be adopted. First, the aperture sheet 20 is prepared. As an example of the apertured sheet 20, for example, a sheet having apertures in the shape and arrangement pattern shown in FIG. An aperture sheet 20 shown in the figure has an X direction and a Y direction perpendicular to the X direction, and has a first aperture row 21 and a second aperture row 22 along the Y direction. The first aperture row 21 and the second aperture row 22 are alternately arranged in the X direction. The first aperture row 21 is configured such that the first apertures 21a are regularly arranged in a line and in a row along the Y direction. Similarly, the second aperture row 22 is configured by arranging the second apertures 22a regularly and in a line along the Y direction. In the plan view of the aperture sheet 20, the first aperture 21 a has a long rectangle in the Y direction. On the other hand, the second opening 22a has a square shape whose dimensions in the X direction and the Y direction are substantially the same.

  When the perforated sheet 20 is prepared, it is arranged as shown in FIG. In this case, the distance d between the second surface 20b of the apertured sheet 20 and the reference surface 15a of the reference surface table 15 is preferably set to 10 mm or more and 20 mm or less, more preferably 5 mm or more and 10 mm or less. By setting the distance between the two in this range, the distance between the reference surface and the aperture sheet can be detected stably. In addition, it is preferable that no member is disposed in the space between the aperture sheet 20 and the reference surface base 15.

  3A and 3B show the results of inspection using the inspection apparatus 10 shown in FIG. 1 for the aperture sheet 20 shown in FIG. FIG. 3A shows the result when the opening is formed satisfactorily, and FIG. 3B shows the result when the opening is defective. In these figures, the vertical axis Z coincides with the Z direction in FIG. The horizontal axis X coincides with the X direction in FIG. Moreover, these figures are the results of measuring the distance D from the reflection position of the laser light to the light receiving portion 12b in the two-dimensional laser displacement meter 11. These results are generated by a determination processing unit (not shown) provided in the controller 13 in the two-dimensional laser displacement meter 11 based on the imaging data transmitted from the sensor head 12 in the two-dimensional laser displacement meter 11. Or a determination processing unit (not shown) connected to the controller 13 via a control line (not shown).

  In FIG. 3A, the position of the symbol a corresponding to the distance D1 is the first surface 20a (see FIG. 1) of the aperture sheet 20, and the fact that the laser beam is reflected by the first surface 20a. Show. That is, the position of symbol a indicates that no aperture is formed in the aperture sheet 20. On the other hand, the position of the symbol b corresponding to the distance D2 is the reference surface 15a in the reference surface table 15, and the laser beam that has passed through the aperture is reflected by the reference surface 15a, and further passes through the aperture and passes through the light receiving portion 12b. Indicates that this has been reached. That is, the position of the symbol b indicates that an aperture is formed in the aperture sheet 20. As is clear from the results shown in FIG. 3, in FIG. 3A, the positions of the symbols a and b are observed alternately and regularly along the X direction of the sheet (see FIG. 2). . This indicates that the opening is clearly formed.

  On the other hand, in FIG. 3B, the position of the code a corresponding to the distance D1 is continuously observed along the X direction, and the position of the code b corresponding to the distance D2 is observed only irregularly. Not. Moreover, a disturbance in the distance is observed at the position of the symbol b. In addition, in FIG. 3B, the position of the code c corresponding to the distance D3 that is neither the position of the code a nor the position of the code b is observed. The position of the code c is slightly closer to the position of the code a than the middle of the position of the code a and the position of the code b. As is apparent from the results shown in FIG. 3, in FIG. 3B, the formation of the opening is defective, and the formation of the opening is incomplete for some reason, or the opening is formed. It is understood that there is no. The reason why the formation of the holes is incomplete is that, for example, the constituent fibers of the hole sheet 20 are present in the holes, the flakes formed by the fibers are present in the holes, or the hole sheet 20. It is inferred that the flakes formed by the constituent fibers are present around the aperture as so-called burrs.

  As described above, according to the present invention, the distance from the reflection position of the laser beam to the light receiving unit 12b in the two-dimensional laser displacement meter 11 is measured, and in the determination processing unit (not shown) based on the measured distance value. By determining the quality of the aperture, the inspection of the aperture sheet 20 can be performed stably and accurately. According to the present invention, it is possible to accurately determine that an opening has been formed even if a small amount of the constituent material of the sheet remains in the opening due to a poor opening of the sheet. Furthermore, since there is no need to install illumination for illuminating the inspection object, erroneous detection is unlikely to occur.

  The above description is for the case where the aperture sheet 20 to be inspected is in a stationary state. However, the present invention can also set the aperture sheet 20 in a moving state to be inspected. This will be described with reference to FIG. FIG. 4 shows an embodiment in which the present invention is applied to a perforated sheet and an absorbent article manufacturing apparatus. The manufacturing apparatus 30 shown in the figure includes an opening forming unit 40, an opening inspection unit 50, a sheet cutting unit 60, and a defective product discharging unit 70 from the upstream side to the downstream side along the sheet conveying direction V. Prepare in order.

  The hole forming unit 40 in the manufacturing apparatus 30 includes a hole forming device including a hole forming roll 41 and a receiving roll 42. Both rolls 41 and 42 are opposed to each other so that their axial centers are parallel to each other and a slight clearance is generated between their peripheral surfaces. Both rolls 41 and 42 are configured to rotate in the same direction as the sheet conveyance direction. Both rolls 41 and 42 can be heated. The sheet passes while being sandwiched between the circumferential surfaces of the two rolls 41 and 42 arranged to face each other.

  The hole forming roll 41 and the receiving roll 42 are in mesh with each other. Specifically, the hole forming roll 41 has a plurality of hole protrusions (not shown) on its peripheral surface. On the other hand, the receiving roll 42 has a groove (not shown) on its peripheral surface. The projection for opening and the groove are fitted with each other. The original sheet 23 before opening is a long material, and is fed from a wound body and a conveying means (both not shown) and supplied between both rolls 41 and 42. The raw sheet 23 supplied between the two rolls 41 and 42 includes an opening projection (not shown) of the opening forming roll 41 and a groove (not shown) recessed in the peripheral surface of the receiving roll 42. By sandwiching between the two, the constituent fibers are separated or the constituent fibers are melted. As a result, an opening is formed in the sheet material 23.

  The long sheet 24 having the openings is guided by the guide rolls 43 and 43 and supplied to the opening inspection unit 50. In the hole inspection section 50, the two-dimensional laser displacement meter 11 and the reference surface table 15 described above are arranged. That is, the above-described opening device of the opening forming unit 40 is disposed at a position upstream of the two-dimensional laser displacement meter 11 and the reference surface base 15 in the conveying direction of the sheet material 23.

  A tension applying means including a pair of tension applying rolls 44 and 44 is disposed in the hole inspection section 50. A pair of tension | tensile_strength provision rolls 44 and 44 are arrange | positioned along the conveyance direction V of the perforated sheet | seat long thing 24 so that the base 15 for base surfaces may be straddled. The tension applying rolls 44 and 44 are configured to be able to irradiate laser light from the two-dimensional laser displacement meter 11 in a state in which tension is applied to the long aperture sheet 24 along the conveying direction V. Tension is applied to the long hole sheet 24 by the tension applying means, and the deformation of the peripheral edge of the hole becomes constant due to this. As a result, it is easy to determine the quality of the aperture described later. Further, fluttering during conveyance of the long sheet 24 is suppressed.

  The controller 13 in the two-dimensional laser displacement meter 11 disposed in the hole inspection unit 50 is connected to the determination processing unit 51. The determination processing unit 51 receives the imaging data acquired by the controller 13 and periodically repeats the collection of imaging data in the conveying direction V of the long aperture sheet 24. The imaging data collected in this way is stored in an imaging data processing device (not shown). Then, a three-dimensional image is generated based on the accumulated imaging data, and the quality of the opening is determined based on the generated three-dimensional image. The determination processing unit 51 enables the hole inspection even while the long sheet 24 is being conveyed. The determination result is notified by transmitting a determination processing signal to the controller 52 of the entire manufacturing apparatus connected to the determination processing unit 51. The imaging data in this embodiment is the distance from the reflection position of the laser beam to the light receiving unit 12b in the two-dimensional laser displacement meter 11.

  The sheet cutting unit 60 installed downstream of the hole inspection unit 50 includes a cutting device 63 having a cutter roll 61 and an anvil roll 62. The cutter roll 61 and the anvil roll 62 are opposed to each other so that their axes are parallel to each other. These are configured to rotate in the same direction as the conveying direction V of the long sheet 24. A cutting blade 64 is formed on the peripheral surface of the cutter roll 61. The cutting blade 64 is formed to extend in the same direction as the direction in which the axis of the cutter roll 61 extends. The long perforated sheet 24 is processed by an absorbent article processing device (not shown) and assembled with the absorbent article, and then the cutting blade 64 of the cutter roll 61 and the peripheral surface of the anvil roll 62 are used. By being pinched and pushed out, it becomes the perforated sheet 20 of each leaf processed as an absorbent article. The cutting device 63 is connected to the controller 52 described above via a motor amplifier 65. The cutting device 63 is configured to receive a command from the controller 52 via the motor amplifier 65 and cut the long perforated sheet 24 across its width direction.

  A position detector 66 is attached to the cutting device 63. The position detector 66 detects the position of the cutting blade 64 of the cutter roll 61 that rotates once for each absorbent article, and uses the position signal P as a reference signal for one absorbent article as a reference signal for the two-dimensional laser. It is configured to transmit to the controller 13 of the displacement meter 11. Based on the reference signal, a three-dimensional image having a size corresponding to one absorbent article is acquired.

  A defective product discharge unit 70 is installed downstream of the sheet cutting unit 60. In the defective product discharge unit 70, when there is a poor hole opening in the perforated sheet 20 cut by the sheet cutting unit 60, the absorbent article including the open sheet 20 is discharged as a defective product. The defective product discharge unit 70 is connected to the controller 52, receives a defective product discharge signal from the controller 52, and discharges the absorbent article including the holed sheet 20 having a defective hole to the outside of the production line. The controller 52 receives the determination processing signal issued from the determination processing unit 51 and transmits a defective product discharge signal to the defective product discharge unit 70 in accordance with the content of the determination processing signal.

  The defective product discharge unit 70 includes a conveyance path changing unit 71. The conveyance path changing means 71 discharges the absorbent article including the path of conveying the absorbent article 80 including the normal apertured sheet 20 to the production line of the subsequent process and the apertured sheet 20 determined to be defective in aperture. It is configured to be able to be switched to a route for transporting to. When the defective product discharge unit 70 receives a defective product discharge signal from the controller 52, the transfer path changing unit 71 transfers the transfer path of the absorbent article from the path for transferring to the manufacturing line in the subsequent process to the discharge line. Switch to. For example, a cylinder mechanism or the like is used for this switching.

  In order to obtain the apertured sheet 20 and subsequently the absorbent article using the manufacturing apparatus having the above configuration, the wound body and the conveying means (both not shown) are driven, and the long sheet original fabric is driven. 1 is conveyed in the direction indicated by reference numeral V in FIG. 1, and a plurality of apertures are formed in the original sheet 23 in the aperture forming section 40. The long sheet 24 in which the opening is formed in this way is inspected for the quality of the opening by the opening inspection unit 50. At the time of inspection, a laser beam is irradiated linearly so as to cross the conveyance direction V toward the long sheet 24 in the conveyance state. Laser light irradiation is performed continuously or intermittently at short intervals. By irradiating the laser beam in this way, the distance from the reflection position of the laser beam to the light receiving unit 12b in the two-dimensional laser displacement meter 11 is acquired over the surface direction of the long sheet 24. An example of the imaging data acquired in this way is shown in FIG. In the figure, directions indicated by reference signs X and Y coincide with the X and Y directions in FIG. In FIG. 5, the Y direction coincides with the transport direction V in FIG. 4.

  In the image shown in FIG. 5, the color differs depending on the distance from the reflection position of the laser light to the light receiving portion 12 b in the two-dimensional laser displacement meter 11. In detail, in this image, the site | part in which the aperture | opening in the aperture sheet 20 was formed is shown with the dark color. That is, this image shows the distance D from the reflection position of the laser beam to the light receiving portion 12b in the two-dimensional laser displacement meter 11 in a color-coded manner in a state in which the aperture sheet 20 to be inspected is viewed in plan. Therefore, it can be said that the image is a three-dimensional image including information on the thickness direction Z in addition to the surface direction XY of the apertured sheet 20. As described above, according to the present embodiment, the two-dimensional laser displacement meter 11 is used to determine the quality of the opening, and the distance D is measured while moving the opening sheet 20 to be inspected. A three-dimensional image of the hole sheet 20 can be obtained.

  In the sheet manufacturing method using the manufacturing apparatus 30 shown in FIG. 4, the hole in the portion corresponding to one product (for example, an absorbent article) in the long sheet 24 in which the hole is formed is poor. When it is determined that the product is a product (for example, an absorbent article) including the portion from the long sheet 24, the product is discarded. The “size corresponding to one product” is the size of the product including the perforated sheet 20 of each leaf cut by the sheet cutting unit 60. In determining the “dimension corresponding to one product”, the position signal P transmitted from the position detector 66 toward the controller 13 of the two-dimensional laser displacement meter 11 in FIG. 4 and the controller of the two-dimensional laser displacement meter 11 are used. The trigger signal T transmitted from the controller 52 of the entire apparatus toward 13 is used. Moreover, the determination of the quality of the opening is performed by the determination processing unit 51 in FIG. The excision of the part is performed in the sheet cutting unit 60. The discarded part is discarded in the defective product discharge section 70.

  Various determination criteria can be adopted for the determination of the quality of the opening in the determination processing unit 51. For example, it can be determined that the hole is defective when all of the holes have holes whose opening rate does not satisfy the reference value at a specific ratio or more. Specifically, among all the holes present in a portion having a dimension corresponding to one product in the long sheet 24 in which the holes are formed, the holes whose opening ratio does not satisfy the reference value are specified. When the ratio is higher than the ratio, it can be determined that the part is a defective product. In this case, the part determined to be defective can be excised and discarded. As the reference value of the open area ratio, various determination criteria can be adopted depending on the specific use of the sheet. For example, 50% or more can be employed. Moreover, 60% or more can be employ | adopted as a ratio of the aperture | open_hole which does not satisfy | fill a reference | standard value, for example. The hole area ratio is a ratio of the area per one hole actually measured by the hole inspection unit 50 to the area per one designed hole.

  As another criterion, for example, in the long sheet 24 in which the apertures are formed, the aperture ratio of all apertures existing in the portion having a size corresponding to one product is measured, and the average of the aperture ratios is measured. If the value does not satisfy the reference value, it can be determined that the part is a defective product, and can be excised and discarded. As an average value of the open area ratio, for example, 50% or more, particularly 60% or more can be adopted.

  In order to obtain the aperture ratio of the aperture from the 3D image obtained based on the accumulation of imaging data, for example, binarization processing of the 3D image is performed, and individual apertures are recognized from the obtained image data. It is only necessary to extract the area to be calculated, calculate the individual area, divide by the area per one design opening, and multiply by 100.

  In the manufacture of the aperture sheet 20 using the aperture sheet manufacturing apparatus shown in FIG. 4, meandering in the width direction occurs while the long sheet 24 having the apertures is being conveyed. There is a case. When meandering of the long sheet 24 occurs, it may be difficult to reliably check the quality of the opening by the two-dimensional laser displacement meter 11. Therefore, it is desirable to correct the deviation of the inspection position caused by meandering so that the inspection position is kept constant even if meandering occurs in the long sheet 24. From this point of view, as shown in FIG. 6, the sheet length to be conveyed is based on the position of the opening existing in the measurement target region and the position of one side edge 24 s along the longitudinal direction Y in the long sheet 24. It is preferable to measure the distance from the reflection position of the laser beam to the light receiving portion 12b in the two-dimensional laser displacement meter 11 while correcting the position of the scale 24 in the width direction X.

  As described above, according to the present invention, the aperture sheet 20 with few defects can be easily manufactured. Furthermore, the present invention can be applied not only to the manufacturing method of the apertured sheet 20 but also to manufacturing methods of various articles including the manufacturing process of the apertured sheet 20. For example, the present invention can be applied to a method for manufacturing an absorbent article provided with the apertured sheet 20. For example, disposable diapers, sanitary napkins and the like are known as absorbent articles, and apertured sheets are often used as absorbent articles, for example, surface sheets. Therefore, an absorbent article with few defects can be easily manufactured by incorporating the inspection method for a perforated sheet described so far into the method for manufacturing an absorbent article.

  Specifically, the step A of forming a plurality of holes in the original sheet while conveying the long sheet original in one direction is performed, and then the sheet having the plurality of openings and the absorbent article In the method for producing an absorbent article by carrying out the process B for producing an absorbent article using other members, such as an absorber and a back sheet, etc., between the process A and the process B, A step of performing the above-described inspection method for an apertured sheet can be interposed. In this case, the process A to the process B can be continuously performed in one production line. Instead of this, the step A and the step of performing the inspection method of the aperture sheet may be continuously performed in one production line, and then the step B may be performed separately. Alternatively, the process A can be continuously performed in one production line, and then the process B for performing the inspection method for the apertured sheet can be performed separately.

  As mentioned above, although this invention was demonstrated based on the preferable embodiment, this invention is not restrict | limited to the said embodiment. For example, in the above-described embodiment, it has been described that the inspection method of the aperture sheet can be incorporated into a part of the manufacturing method of the absorbent article. However, the inspection method of the aperture sheet is one of the manufacturing methods of other articles. It may be incorporated in the part.

  Further, when the width of the long sheet 24 having the opening is large, a plurality of two-dimensional laser displacement meters 11 are used, and the sensor head 12 in the displacement gauge 11 is connected to the width direction X of the long sheet 24. It is also possible to inspect the quality of the opening by arranging a plurality of the holes along the line.

  In the above-described embodiment, the two-dimensional laser displacement meter 11 is disposed on one surface of the sheet to be inspected, and the reference surface table 15 is disposed on the other surface side. Depending on the required accuracy of the inspection, only the two-dimensional laser displacement meter 11 may be disposed, and the reference surface table 15 may not be disposed.

DESCRIPTION OF SYMBOLS 10 Inspection apparatus 11 Two-dimensional laser displacement meter 12 Sensor head 12a Irradiation part 12b Light reception part 13 Controller 15 Reference surface base 15a Reference surface 20 Hole sheet 20a First surface 20b Second surface 21 First hole row 22 2nd opening row | line | column 21a, 22a Opening hole 23 Sheet | seat original fabric 24 The sheet | seat long thing 30 in which the opening was formed 30 Opening sheet manufacturing apparatus 40 Opening formation part 41 Opening formation roll 42 Receiving roll 43 Guide roll 44 Tension applying roll 50 Opening inspection unit 51 Determination processing unit 52 Controller 60 Sheet cutting unit 61 Cutter roll 62 Anvil roll 63 Cutting device 64 Cutting blade 66 Position detector 70 Defective product discharge unit 80 Absorbent article

Claims (12)

A step of disposing a two-dimensional laser displacement meter on one surface side of a sheet having a plurality of apertures, and using the two-dimensional laser displacement meter to irradiate a laser beam toward the sheet and receiving the reflected light; ,
Measuring the distance from the reflection position of the laser beam to the light receiving part in the two-dimensional laser displacement meter,
And a step of determining the quality of the opening based on the measured distance value.   The inspection method for a perforated sheet according to claim 1, wherein a reference surface base is disposed on the other surface side of the sheet.   The long sheet is conveyed in one direction, and laser light is irradiated linearly so as to cross the conveyance direction toward the sheet in the conveyance state, so that the distance extends over the surface direction of the sheet. The method for inspecting an apertured sheet according to claim 1 or 2, wherein the quality of each aperture is determined by acquiring and measuring the aperture ratio of each aperture.   The method for inspecting an apertured sheet according to claim 3, wherein laser light is irradiated under a state where tension is applied to the sheet along a conveying direction.   The method for inspecting a perforated sheet according to claim 3 or 4, wherein among all the perforations, if there are perforations in which the perforation rate does not satisfy a reference value or more, a defect is determined.   Measure the open area ratio of all the holes present in the part of the long sheet in the dimension corresponding to one product, and if the average value of the open area ratio does not meet the standard value, it is defective The method for inspecting an apertured sheet according to claim 3 or 4, wherein A two-dimensional laser displacement meter disposed on one side of the sheet having a plurality of apertures;
An inspection apparatus for an aperture sheet, comprising: a determination processing unit that determines pass / fail of the aperture based on imaging data transmitted from the two-dimensional laser displacement meter.   The perforated sheet inspection apparatus according to claim 7, wherein a reference surface base is disposed on the other surface side of the sheet. It further has conveying means for conveying the long sheet in one direction,
The opening device for opening the raw material of this sheet | seat is distribute | arranged to the position of the upstream in the conveyance direction of the said sheet | seat rather than the said two-dimensional laser displacement meter and the said base for bases. The inspection apparatus of an aperture sheet as described.   The perforated sheet inspection apparatus according to claim 9, further comprising a tension applying unit capable of applying a tension to the sheet along a conveying direction of the long sheet. Forming a plurality of apertures in the sheet while conveying the long sheet raw material in one direction;
A two-dimensional laser displacement meter is disposed on one surface side of a sheet having a plurality of apertures, and the two-dimensional laser displacement meter is used to direct the laser beam to the sheet in a conveying state so as to intersect the conveying direction. And receiving the reflected light in a linear manner,
Measuring the distance from the reflection position of the laser beam to the light receiving portion in the two-dimensional laser displacement meter over the surface direction of the sheet;
And a step of determining the quality of the aperture based on the measured distance value. Forming a plurality of apertures in the original sheet while conveying the elongated original sheet in one direction;
A process for producing an absorbent article using a sheet having a plurality of apertures and another member constituting the absorbent article,
The manufacturing method is
A two-dimensional laser displacement meter is disposed on one surface side of the sheet having a plurality of apertures, and the two-dimensional laser displacement meter is used to direct the laser so as to cross the conveyance direction toward the sheet in the conveyance state. Irradiating light linearly and receiving the reflected light;
Measuring the distance from the reflection position of the laser beam to the light receiving portion in the two-dimensional laser displacement meter over the surface direction of the sheet;
And a step of determining the quality of the opening based on the measured distance value.