JP7572988B2 - Fiber stacking device and method for manufacturing absorbent body - Google Patents

Description

The present invention relates to a fiber stacking device and a method for manufacturing an absorbent body.

Conventionally, absorbents used in absorbent articles such as disposable diapers, sanitary napkins, and incontinence pads are known that are formed so that the thickness of the central portion is greater than that of the other portions, i.e., the basis weight of the central portion (hereinafter referred to as the "high central portion") is greater than that of the other portions. Absorbents with such high central portions can improve the wearing comfort and leakage prevention when worn.

Most absorbents with a high-centered section are manufactured (formed) using a fiber-stacking device that includes a rotating drum with an accumulation recess on its outer periphery and a duct that supplies the raw fiber material to the outer periphery of the rotating drum. Absorbents are manufactured using such a fiber-stacking device by following the steps of (1) supplying the fiber material into the duct while rotating the rotating drum around its axis of rotation, and (2) stacking the fiber material in the accumulation recess by sucking from the bottom side of the accumulation recess, which has multiple suction holes.

In such fiber stacking devices, a recess for forming a higher middle section (hereinafter referred to as the "high middle section forming recess") is formed in part of the bottom surface of the accumulation recess, and fiber material is piled up in the accumulation recess including this high middle section forming recess, thereby forming an absorbent body having a high middle section.

However, conventional fiber stacking devices are designed so that the suction force generated at the bottom of the stacking recess naturally decreases as fiber material accumulates in the stacking recess, and there is a risk that sufficient suction force may not be obtained, particularly in the deep recess for forming the central high section. In such cases, problems arise such as uneven fiber stacking density (fiber density) near the central high section forming recess, or the surface opposite the surface where the central high section is formed becoming concave, making it difficult to maintain a consistent quality.

Therefore, in order to solve these problems, various fiber stacking devices have been proposed. Examples of such fiber stacking devices include the devices described in Patent Documents 1 to 3.

In the fiber stacking device described in Patent Document 1, the downstream opening of the duct is disposed opposite a part of the outer circumferential surface of the rotating drum, and the downstream end of the duct that defines the opening includes a pair of drum rotation direction corresponding parts that extend in the rotation direction of the rotating drum across the accumulation recess, and the pair of drum rotation direction corresponding parts are each disposed with a gap from the outer circumferential surface of the rotating drum, and the gap is configured to be adjusted by a gap adjustment mechanism. With such a fiber stacking device, the amount of air flowing into the duct from outside the duct through the gap can be adjusted by adjusting the gap with the gap adjustment mechanism, and such adjustment of the amount of air makes it possible to efficiently manufacture medium- to high-absorbency bodies.

The fiber stacking device described in Patent Document 2 has a pair of stacking plates facing each other and spaced apart in the width direction of the rotating drum, and the distance between the downstream rear edges of the stacking plates is narrower than the distance between the upstream front edges, so that the fiber material collected between the stacking plates is directed toward the recessed area for forming the middle-high portion on the peripheral surface of the fiber stacking drum. With this type of fiber stacking device, more fiber material is stacked on the peripheral surface of the fiber stacking drum, particularly in the recessed area for forming the middle-high portion, than in other areas, so that low-density areas can be prevented from being formed, and the depth of the recessed area for forming the middle-high portion can be made approximately the same as the height of the middle-high portion in the finished product.

The fiber stacking device described in Patent Document 3 divides the suction chamber disposed inside the rotating drum into multiple suction chambers in a cross section along the flow direction, and provides individual suction means for each of the multiple suction chambers. With this type of fiber stacking device, it is possible to make the thickness of the absorbent body uniform in the width direction, and it is also possible to partially change the basis weight and form bulky parts (middle-height parts).

JP 2017-051316 A JP 2007-260297 A JP 2002-272782 A

However, in the fiber stacking device described in Patent Document 1, the gap that adjusts the amount of air flowing into the duct is located adjacent to the accumulation recess of the rotating drum, so there is a possibility that the fiber material will accumulate in the accumulation recess without changing the flow of the fiber material circulating in the duct, and depending on the amount of air flowing into the duct, there is a risk that the fiber material accumulated in the accumulation recess will be blown away. In such cases, problems arise such as it becoming difficult to manufacture absorbents of consistent quality.

On the other hand, the fiber stacking device described in Patent Document 2 is configured such that as the fiber material passes over the accumulation plate, the flow direction is forcibly changed from a flow toward the recess for forming the central high section. Depending on the shape of the accumulation plate, the fiber material may accumulate, for example, on the upstream end of the accumulation plate. In such a case, when the absorbent body is manufactured, the clumps of fiber material accumulated on the accumulation plate may fall into the accumulation recess, resulting in a problem of a deterioration in the quality of the absorbent body.

In addition, the fiber stacking device described in Patent Document 3 is configured to manufacture absorbent bodies by controlling the suction means provided in each of the multiple suction chambers, which creates problems such as a complex device configuration and difficulty in adjusting the suction force when manufacturing absorbent bodies.

The present invention is directed to providing a fiber stacking device and a method for manufacturing an absorbent body that can eliminate the drawbacks of the conventional technology described above.

The present invention relates to a fiber stacking device that includes a rotating drum having an accumulation recess formed on its outer peripheral surface and a duct for supplying raw material to the outer peripheral surface, and that rotates the rotating drum around its rotation axis while transporting the raw material using an air flow generated in the duct by suction from the inside of the rotating drum, thereby stacking the raw material in the accumulation recess.
The duct of the fiber stacking device preferably has an opening on each of a pair of opposing wall surfaces opposed to each other in the axial direction of the rotating shaft, the opening being spaced from the downstream edge adjacent to the rotating drum. The fiber stacking device preferably has a control mechanism provided in the duct for controlling the amount of air flowing into the duct through the opening.

The present invention also relates to a method for manufacturing an absorbent body using the fiber stacking device.
The fiber stacking device preferably includes a rotating drum having an accumulation recess formed on its outer peripheral surface and rotating around a rotation axis, and a duct for supplying raw material to the outer peripheral surface, and the duct preferably has an opening on each of a pair of opposing wall surfaces opposing each other in the axial direction of the rotating axis, the opening being spaced from the downstream edge adjacent to the rotating drum. The fiber stacking device preferably includes a control mechanism for controlling the amount of air flowing into the duct through the opening. The manufacturing method preferably includes a raw material supplying step of supplying raw material to the duct while rotating the rotating drum around the rotation axis, an air flow adjusting step of adjusting an air flow generated in the duct by suction from the inside of the rotating drum by controlling the control mechanism, and a fiber stacking step of stacking the raw material transported on the air flow in the accumulation recess.

The fiber stacking device and absorbent body manufacturing method of the present invention have a relatively simple device configuration, yet can stack a large amount of raw material in a specific location of the accumulation recess, making it possible to manufacture fiber stacks and absorbent bodies of the desired shape with consistent quality.

FIG. 1 is a perspective view showing a fiber stacking device according to an embodiment of the present invention, with some parts being see-through. FIG. 2 is a schematic side view of the fiber stacking device shown in FIG. 1 as viewed from the drum width direction. FIG. 3 is a schematic exploded perspective view of the stacking unit of the manufacturing apparatus shown in FIG. FIG. 4 is a schematic plan view of a part of the accumulation recess of the manufacturing apparatus shown in FIG. 5 is a cross-sectional view showing a schematic cross section taken along line II in FIG. 4 (a cross section along the drum width direction of the low basis weight portion corresponding portion), in which FIG. 5(a) shows the suction state in the high basis weight portion preferential stacking region, and FIG. 5(b) shows the suction state in the full-area stacking region. 6 is a cross-sectional view showing a schematic cross section taken along line II-II in FIG. 4 (a cross section along the drum width direction of the portion corresponding to the high basis weight portion), in which FIG. 6(a) shows the suction state in the high basis weight portion preferential stacking region, and FIG. 6(b) shows the suction state in the full-area stacking region. FIG. 7 is a schematic plan view showing the flow of vacuum air on the surface of the accumulation recess. FIG. 8 is a schematic perspective view of one embodiment of an absorbent body provided by the present invention. FIG. 9 is a graph showing test results comparing the basis weight of the absorbent body formed when the shutter member is moved to the closed position with the basis weight of the absorbent body formed when the shutter member is moved to the open position. FIG. 10 is a schematic side view of the fiber stacking device according to the first modification when viewed from the drum width direction. FIG. 11 is a schematic diagram showing a fiber stacking device according to the second modified example, where FIG. 11(a) is a perspective view and FIG. 11(b) is a side view. FIG. 12 is a schematic side view of the fiber stacking device according to the fourth modification, as viewed from the drum width direction. FIG. 13 is a schematic side view of the fiber stacking device according to the fifth modification, as viewed from the drum width direction.

The present invention will now be described based on preferred embodiments thereof with reference to the drawings. In the following description of the drawings, the same or similar parts are denoted by the same or similar reference numerals. The drawings are essentially schematic, and the ratios of the dimensions may differ from the actual ones.

1 and 2 show a schematic configuration of a fiber stacking device 1 according to one embodiment of the present invention.
The fiber stacking device 1 according to this embodiment includes an accumulation section 4 having a rotating drum 3, a raw material supply mechanism 5 that supplies raw materials such as fiber materials to the accumulation section 4, and a transport mechanism 6 that transports the absorbent body 10 discharged from the accumulation recess 40 of the rotating drum 3. The absorbent body 10 is a stack of raw materials such as fiber materials. The absorbent body 10 manufactured using the fiber stacking device 1 will be described later.

The accumulation section 4 includes a fixed drum 2 and a rotating drum 3 that is rotatable around the outer periphery 2S of the fixed drum 2 and has an accumulation recess 40 on its outer periphery 3S (see FIG. 1) in which the fiber material is accumulated. In the fiber accumulation device 1 according to this embodiment, the fiber accumulation device 1 is configured to accumulate fiber on the bottom surface of the accumulation recess 40 in a predetermined fiber accumulation region S in the drum circumferential direction X1 while rotating the rotating drum 3.

The raw material supply mechanism 5 includes a duct 51 having a raw material supply path 50 therein, and a raw material introduction section 58 that introduces raw materials into the duct 51. The duct 51 has openings at both ends in the raw material supply direction (hereinafter simply referred to as the "supply direction"), with the downstream end covering part of the outer periphery of the accumulation section 4 (the rotating drum 3), and the upstream end being provided with a crusher CS provided in the raw material introduction section 58. In this embodiment, the duct 51 has a pair of left and right openings 52, 52 formed in a pair of opposing wall surfaces that face each other along the axial direction of the rotating drum 3, and each opening 52 is provided with an opening/closing member, i.e., a shutter member 53, that can move between a "closed position" that closes the opening and an "open position" that opens it.

The raw material introduction section 58 is configured to crush the sheet-shaped wood pulp SP using a crusher CS to produce pulp fibers, which are a fibrous material, and to feed the pulp fibers into the duct 51. The duct 51 is also provided with a water-absorbent polymer introduction section 59 that introduces water-absorbent polymer particles into the supply path 50.

The transport mechanism 6 is provided with a vacuum conveyor (not shown) that is disposed below the accumulation section 4 and transports the absorbent body 10 discharged from the accumulation section 4 while sucking it onto the transport surface. A blow generating mechanism (not shown) is disposed inside the fixed drum 2 in the accumulation section 4, and the blow generating mechanism blows air from the inside of the accumulation section 4 towards the outer periphery 3S side of the rotating drum 3, causing the absorbent body 10 to be discharged from the accumulation recess 40 of the outer periphery 3S and transferred onto the transport surface of the vacuum conveyor.
In this embodiment, a sheet material 14 (see FIG. 2), also called a core wrap sheet or the like, which covers the outer surface of the absorbent body 10, is arranged in advance on the transport surface of the vacuum conveyor, and the absorbent body 10 discharged from the accumulation unit 4 is transferred onto the sheet material 14 and transported together with the sheet material 14. The sheet material 14 is folded so as to cover the entire absorbent body 10 during transport by the vacuum conveyor.

As shown in Figures 1 to 3, the stacking section 4 is mainly composed of a fixed drum 2 made of a rigid metal body and a rotating drum 3 arranged on top of the outer periphery 2S of the fixed drum 2, and has a cylindrical shape. The rotating drum 3 receives power from a prime mover such as a motor and rotates in direction R1 along the drum circumferential direction X1 around a horizontal rotation axis, while the fixed drum 2 does not rotate. The stacking section 4 has a drum circumferential direction X1 corresponding to the circumferential direction of both drums 2, 3, and a drum width direction Y1 corresponding to the direction in which the rotation axis of the rotating drum 3 extends.

The fixed drum 2 has a cylindrical shape, and openings at both axial ends of the cylindrical fixed drum 2 are airtightly sealed by side walls 21 and a sealing material such as felt (not shown). The inside of the fixed drum 2 is divided into a plurality of sections (three in this embodiment) in the circumferential direction by partitions 22, and a plurality of spaces A to C corresponding to the sections are formed.
A pressure reducing mechanism (not shown) for reducing the pressure inside the fixed drum 2 is connected to the fixed drum 2. The pressure reducing mechanism includes an exhaust pipe (not shown) connected to the side wall 21 and an exhaust fan (not shown) connected to the exhaust pipe. By operating the pressure reducing mechanism, any of the multiple spaces A to C inside the fixed drum 2 is maintained at a negative pressure. The fixed drum 2 is configured so that the negative pressures (suction forces) of the multiple spaces A to C separated by partitions 22 can be independently adjusted.

The rotating drum 3 has an accumulation recess 40 on its outer periphery 3S where the fiber material is piled up. As shown in FIG. 4, the accumulation recess 40 has a high basis weight portion corresponding portion 41 that forms the high basis weight portion 11 (see FIG. 8(a)) of the absorbent body 10, which is the object of manufacture, and a low basis weight portion corresponding portion 42 that forms the low basis weight portion 12 (see FIG. 8(a)) of the absorbent body 10, in the drum circumferential direction X1. The bottom surface of the accumulation recess 40 where the fiber material is piled up is made of a breathable member (the "first recess bottom forming plate 34" in FIG. 5 and the "second recess bottom forming plate 36" in FIG. 6) that has a large number of suction holes through which vacuum air can pass, and is breathable.

In this embodiment, the accumulation recesses 40 are arranged continuously over the entire length of the rotating drum 3 in the drum circumferential direction X1, and the high basis weight section corresponding sections 41 and the low basis weight section corresponding sections 42 are arranged alternately over the entire length of the drum circumferential direction X1. One high basis weight section corresponding section 41 and two low basis weight section corresponding sections 42, 42 arranged at the front and rear of the high basis weight section corresponding section 41 in the drum circumferential direction X1 correspond to one absorbent body 10, so the absorbent body 10 discharged from the accumulation recesses 40 to the vacuum conveyor of the transport mechanism 6 is a continuous absorbent body in which multiple absorbents 10 are connected in the vertical direction X.

As shown in Figures 1 and 2, the rotating drum 3 moves around the outer periphery 2S of the fixed drum 2 from the upstream side to the downstream side in the rotation direction R1, in the order of the area corresponding to space A, the area corresponding to space B, and the area corresponding to space C. The "area corresponding to space A" refers to the area that overlaps with the extension part when space A of the fixed drum 2 is virtually extended outward in the radial direction of the fixed drum 2 (direction perpendicular to the drum width direction). The "area corresponding to space B" and the "area corresponding to space C" are the same as those in the above explanation of the "area corresponding to space A" with "space B" or "space C" substituted for "space A".

In this embodiment, the area corresponding to spaces A and B is the fiber stacking area S where the fiber material is stacked in the accumulation recess 40, and the opening on one end side of the duct 51 of the raw material supply mechanism 5 covers the fiber stacking area S. Of the fiber stacking area S, the area corresponding to space A is the high basis weight portion priority fiber stacking area S1 described below, and the area corresponding to space B is the full-area fiber stacking area S2 described below.

When the decompression mechanism is operated and the rotating drum 3 is rotated in the rotation direction R1 while spaces A and B of the fixed drum 2 are maintained at negative pressure, while the accumulation recess 40 of the rotating drum 3 passes through the area corresponding to spaces A and B, i.e., the fiber-stacking area S, the negative pressure in spaces A and B acts on the breathable member (the "first recess bottom forming plate 34" in FIG. 6 and the "second recess bottom forming plate 36" in FIG. 5) that forms the bottom of the accumulation recess 40, and vacuum air is sucked through the numerous suction holes of the breathable member. This suction through the suction holes generates vacuum air toward the fiber-stacking area S in the supply path 50 in the duct 51 that covers the fiber-stacking area S, and raw materials such as fiber materials carried by this vacuum air are supplied to the fiber-stacking area S.

As shown in FIG. 3, on the outer periphery 2S of the fixed drum 2, a selective suction area 23 where suction from the inside of the fixed drum 2 is partially possible, and a full suction area 24 where suction is possible completely are arranged side by side in the drum circumferential direction X1. In this embodiment, they are arranged in this order in the rotation direction R1 of the rotating drum 3. The selective suction area 23 corresponds to space A (see "high basis weight section priority fiber stacking area S1" in FIG. 2), and the full suction area 24 corresponds to space B (see "full fiber stacking area S2" in FIG. 2).

The selective suction region 23 is made of a non-breathable member partially provided with openings, and the vacuum air can pass through the selective suction region 23 in the thickness direction only through the openings. In this embodiment, a suction controller 25 corresponding to the above-mentioned "non-breathable member partially provided with openings" is arranged in a portion corresponding to the selective suction region 23 in the outer circumferential portion 2S of the fixed drum 2. The suction controller 25 has one or more controller openings 26 penetrating the suction controller 25 in the thickness direction. In the illustrated embodiment, the controller openings 26 have a band shape (straight line shape) extending in the drum circumferential direction X1 in a plan view, and are arranged at a predetermined interval in the drum width direction Y1. The suction controller 25 is non-breathable, and therefore, suction is not possible in the portion of the suction controller 25 other than the controller openings 26. Metal, resin, etc. can be used as the non-breathable member constituting the suction controller 25.
On the other hand, the full-surface suction region 24 does not include an air-impermeable member, and the entire area of the portion corresponding to the accumulation recess is open, so that the vacuum air can pass through the entire full-surface suction region 24 in the thickness direction.

In this specification, a "plan view" or "plan view" of a curved portion, such as the outer periphery of the accumulation section 4 (fixed drum 2, rotating drum 3), refers to the curved portion (e.g., suction control body 25, accumulation recess 40, etc.) as viewed from the outside in the normal direction of the curved portion (direction perpendicular to the drum width direction).

The rotating drum 3 includes a cylindrical metallic drum main body 3A disposed closest to the fixed drum 2 and facing the outer circumferential portion 2S of the fixed drum 2, and an outer layer portion 3B consisting of a plurality of members 36-38 etc. disposed in layers on the outer circumferential portion 3AS of the drum main body 3A.
In this embodiment, the drum body 3A is a ring-shaped member that is continuous over the entire length in the drum circumferential direction X1, while the multiple members 36-38 constituting the outer layer portion 3B are each divided into multiple parts in the drum circumferential direction X1. These multiple members 36-38 are joined to each other so as to be freely attached and detached, and are also joined to the outer circumferential portion 3AS of the drum body 3A so as to be freely attached and detached, by fasteners such as bolts, joining means such as adhesives, etc.

The outer periphery 3AS of the drum body 3A faces the outer periphery 2S of the fixed drum 2, and a non-breathable opening closure member 30 is disposed on this outer periphery 3AS in correspondence with the low basis weight portion corresponding portion 42 (see FIG. 4) of the accumulation recess 40. On the other hand, the opening closure member 30 is not disposed on the portion 32 of the outer periphery 3AS of the drum body 3A that corresponds to the high basis weight portion corresponding portion 41 (see FIG. 4) of the accumulation recess 40. Metal, resin, etc. can be used as the non-breathable material for forming the opening closure member 30.

In this embodiment, suction inhibition sections 31 having an opening closing member 30 arranged on the outer circumferential portion 3AS of the drum main body 3A and suction non-inhibition sections 32 having no opening closing member 30 and consisting of through holes penetrating the outer circumferential portion 3AS in the thickness direction are arranged alternately in the drum circumferential direction X1.
In each of the plurality of suction inhibition sections 31, the number of the opening closing members 30 arranged in the drum width direction Y1 is set to be the same as the number of the control body openings 26 arranged in the drum width direction Y1 in the selective suction region 23 of the outer circumferential portion 2S of the fixed drum 2. In the illustrated embodiment, the number of the control body openings 26 arranged in the drum width direction Y1 is three, so the number of the opening closing members 30 arranged in the drum width direction Y1 in the suction inhibition section 31 is also three. In each of the plurality of suction inhibition sections 31, the plurality of opening closing members 30 (in this embodiment, "three") have a belt shape (straight line shape) extending in the drum circumferential direction X1 in a plan view, and are intermittently arranged in the drum width direction Y1. The opening closing members 30 are arranged at the same position as the control body openings 26 in the drum width direction Y1, and when the selective suction region 23 and the suction inhibition section 31 are overlapped, the control body openings 26 of the selective suction region 23 are closed by the opening closing members 30 of the suction inhibition section 31.
Note that "closing" here includes (1) a form in which the opening closure member 30 overlaps the regulator opening 26 so that the vacuum air cannot pass through the regulator opening 26, i.e., suction at the regulator opening 26 is completely impossible, and (2) a form in which the opening closure member 30 overlaps the regulator opening 26 to an extent that suction at the regulator opening 26 is somewhat possible. Both of the above-mentioned forms (1) and (2) are the same in that suction at the regulator opening 26 is hindered by the opening closure member 30.
On the other hand, the suction non-inhibition portion 32 does not include an air-impermeable member such as the opening closing member 30, and the entire area of the portion corresponding to the accumulation recess is open. Therefore, the vacuum air can pass through the entire area of the suction non-inhibition portion 32 in the thickness direction.

In this embodiment, the outer layer 3B of the rotating drum 3 is a laminate of multiple members as described above. Specifically, as shown in FIG. 3, the multiple members constituting the outer layer 3B include, in order of proximity to the drum body 3A, the first recess bottom forming plate 34 (see FIG. 6), the second recess bottom forming plate 36 (see also FIG. 5), the recess partition plate 37, and the ring plate 38. Of these multiple members, the second recess bottom forming plate 36 and the recess partition plate 37 have the same length (width) in the drum width direction Y1, and the width of the outer layer 3B is the same as the width of each of these plates 36, 37.

The ring plate 38 is disposed on the outermost side of the rotating drum 3. The ring plate 38 is narrower than the plates 36, 37, and is disposed as a pair on both sides in the drum width direction Y1 with the accumulation recess 40 in between, as shown in Figures 3 and 4 .
The recess partitioning plate 37 is used to form groove-shaped recesses 13X, 13Y in the absorbent body 10, and in the portion of the recess partitioning plate 37 corresponding to the accumulation recess 40, a plurality of partition members 370 (see Figures 4 and 7) are arranged in the same pattern as the groove-shaped recesses 13X, 13Y.

As shown in Figures 3, 5 and 6, the first recess bottom forming plate 34 and the second recess bottom forming plate 36 each form the bottom of the accumulation recess 40 in which the fiber material is stacked, and are breathable members having a large number of suction holes through which vacuum air can pass.
The first recess bottom forming plate 34 is used to form the middle portion 11A, which is a part of the high basis weight portion 11 of the absorbent body 10 (see FIG. 8(a)), and corresponds to the high basis weight portion corresponding portion 41 of the accumulation recess 40. In this embodiment, the first recess bottom forming plate 34 has a substantially rectangular shape in a plan view, and is narrower than the second recess bottom forming plate 36.
The second recess bottom forming plate 36 is used to form the portion of the absorbent body 10 other than the high middle portion 11A, and corresponds to the low basis weight portion corresponding portion 42 of the accumulation recess 40 and the portion of the high basis weight portion corresponding portion 41 other than the portion corresponding to the high middle portion 11A (see FIG. 8(a)). In the portion of the second recess bottom forming plate 36 that overlaps with the first recess bottom forming plate 34 in a plan view, an opening 360 having the same shape as the shape of the first recess bottom forming plate 34 in a plan view is formed in correspondence with the plate 34.

As shown in Figure 2, in the fiber stacking device 1 of this embodiment, the rotating drum 3 rotates, and while the accumulation recess 40 on the outer periphery 3S of the rotating drum 3 passes through the fiber stacking area S, raw materials such as fiber material supplied by the duct 51 are stacked in the accumulation recess 40, thereby forming an absorbent body 10 in the accumulation recess 40.
In addition, in this embodiment, as one of the measures for obtaining an absorbent 10 having a relatively large difference in basis weight between the high basis weight portion 11 and the low basis weight portion 12 (see FIG. 8(a)), the conveying path of the accumulation recess 40 in the fiber stacking area S is divided into a plurality of areas S1, S2 in the conveying direction (drum circumferential direction X1), and the fiber stacking method of each area S1, S2 is made different from each other. Specifically, the fiber stacking area S of the fiber stacking device 1 has, in the drum circumferential direction X1, a high basis weight portion preferential stacking area S1 in which the fiber material is preferentially stacked in the high basis weight portion corresponding area 41, and a full-area stacking area S2 in which the fiber material is stacked in both the high basis weight portion corresponding area 41 and the low basis weight portion corresponding area 42.

In this embodiment, as shown in FIG. 2, the area corresponding to space A is the high basis weight portion priority fiber stacking area S1, and the area corresponding to space B is the full-area fiber stacking area S2, which are arranged in this order in the rotation direction R1 of the rotating drum 3, i.e., the flow direction MD (see FIG. 1). Note that in the absorbent body manufacturing apparatus of the present invention, the positions of the two areas S1 and S2 are not particularly limited, and they may be arranged in the order of the full-area fiber stacking area S2 and the high basis weight portion priority fiber stacking area S1 from the upstream side to the downstream side of the flow direction MD, opposite to the illustrated form.

One of the main features of the fiber stacking device 1 according to this embodiment is that it is equipped with a pair of left and right openings 52, 52 formed in the duct 51, and shutter members 53 provided in each of these openings 52, 52.
The pair of openings 52, 52 and the shutter member 53 will be described below with reference to Figures 1 and 2. Note that since the pair of openings 52, 52 have the same configuration, one of the openings 52 will be described and a description of the other opening 52 will be omitted unless necessary. Similarly, the shutter members 53 provided in each of these openings 52, 52 have approximately the same configuration, so for convenience of explanation, one of the shutter members 53 will be described and a description of the other shutter member 53 will be omitted unless necessary.

1, 2 and 4, the pair of openings 52, 52 are formed symmetrically (line-symmetrically) on a pair of opposing wall surfaces facing each other in the axial direction of the rotation shaft of the rotating drum 3, and open at a position spaced apart from the edge of the duct 51 facing the outer periphery 3S of the rotating drum 3. In this embodiment, the openings 52 are formed in each of the pair of opposing wall surfaces as a plurality of openings 52a, 52b (two in the illustrated example), and each of the plurality of openings 52a, 52b has a curved shape that follows the shape of the outer periphery of the rotating drum 3 (accumulation recess 40). The plurality of openings 52a, 52b are arranged in the high basis weight portion preferential fiber stacking region S1 (see FIG. 2) at a predetermined interval from each other, and are arranged side by side along the outer periphery 3S of the rotating drum 3. In this embodiment, the openings 52a and 52b are formed to have substantially the same shape and size (see FIG. 2, etc.), but either or both of the shape and size may be different from each other.

Here, a description will be given of the flow of vacuum air circulating through the duct 51 when the fiber stacking device 1 is in operation, in which the pair of left and right openings 52, 52 are provided with the duct 51.
As described above, in this embodiment, when the fiber stacking device 1 is operated, suction from the inside of the rotating drum 3 ("Space A" and "Space B") generates an airflow in the supply path 50 in the duct 51 toward the accumulation recess 40. Since a pair of left and right openings 52, 52 are formed in the duct 51, when an airflow toward the accumulation recess 40 is generated in the duct 51, air present outside the openings 52 is induced (pulled in), and air (hereinafter referred to as "induced air") naturally flows into the duct 51 through the openings 52, 52.

As a result, when the vacuum air passes through the openings 52, 52 in the duct 51, the induced air changes the flow toward the center of the width direction of the rotating drum 3 (hereinafter referred to as the "drum width direction") (see Figures 6(a) and 7). That is, in this embodiment, while the fiber stacking device 1 is in operation, the raw material contained in the vacuum air can be transported toward the center of the drum width direction of the accumulation recess 40, and the raw material can be stacked (accumulated) satisfactorily at the desired position of the accumulation recess 40 (in this embodiment, the first recess bottom forming plate 34 (high basis weight portion corresponding portion 41, see Figures 4, 6(a) and 8(a), etc.) that forms the middle-high portion 11A of the absorbent body 10).

Although details will be described later, in this embodiment, by adjusting the amount of induced air flowing into the duct 51 through the openings 52, 52, it is possible to increase or decrease the basis weight of the desired portion of the absorbent body 10 (see FIG. 8) (in this embodiment, the middle-high portion 11A (see FIG. 8)). In addition, since the amount of induced air flowing into the duct 51 can be adjusted simply by moving the shutter member 53 arranged on the outer surface of the duct 51, the adjustment work is extremely simple. In other words, in this embodiment, while the device configuration is relatively simple, it is possible to deposit raw materials aimed at specific portions of the accumulation recess 40, making it possible to manufacture absorbent bodies 10 of the desired shape with consistent quality.

In this embodiment, each of the multiple openings 52a, 52b has a curved shape that conforms to the shape of the outer circumferential surface of the rotating drum 3 (accumulation recess 40). That is, the distance D (see FIGS. 2 and 6(a)) between the downstream opening periphery of the openings 52a, 52b and the outer circumferential portion 3S of the rotating drum 3 is constant, so that it is possible to stably (always) supply approximately the same amount of induced air into the duct 51.
Furthermore, in this embodiment, the multiple openings 52a, 52b are arranged side by side along the circumferential direction X1 (see FIG. 1) of the rotating drum 3. That is, in this embodiment, the vacuum air flowing along the circumferential direction X1 of the rotating drum 3 can be effectively converged toward the center in the drum width direction by the induced air through the openings 52a, 52b. Therefore, in this embodiment, raw materials such as fiber materials can be more reliably stacked on the first recess bottom forming plate 34 (high basis weight portion corresponding portion 41, see FIGS. 4, 6(a), 8(a), etc.) that forms the central high portion 11A of the absorbent body 10.

The distance d (see FIG. 6(a)) between the opening 52 (openings 52a, 52b) and the outer periphery 3S of the rotating drum 3 is preferably 5 mm or more and 100 mm or less. In other words, the opening 52 has a downstream opening periphery that is preferably 5 mm or more and 100 mm or less away from the surface of the outer periphery 3S of the rotating drum 3.
If the opening 52 is formed at a position that is extremely close to the surface of the outer circumferential portion 3S of the rotating drum 3, for example, at a position 1 to 2 mm from the surface, the flow of the vacuum air containing the raw materials will reach the accumulation recess 40 with almost no change due to the induced air, making it difficult to control the accumulation of the raw materials in a large amount in the desired portion of the accumulation recess 40.
In contrast, by making the distance d 5 mm or more, it becomes easy to change the flow of the vacuum air by induced air, and it becomes easy to stack the raw material at a desired position in the accumulation recess 40, for example, the first recess bottom forming plate 34 (see Figures 4 and 6(a) and the like) in this embodiment. The distance d is preferably 5 mm or more, and more preferably 20 mm or more.
On the other hand, by setting the distance d to 100 mm or less, it is possible to prevent inconveniences that tend to occur when the distance is set too far, such as the vacuum air once converging (focusing) toward the center in the drum width direction by the induced air dispersing (diffusing) before reaching the accumulation recess 40, which ultimately makes it impossible to stably stack the raw materials in the vacuum air at the desired position in the accumulation recess 40. The distance d is preferably 100 mm or less, and more preferably 60 mm or less.

In this embodiment, the accumulation section 4 and the duct 51 are configured to be connected with a gap G (see FIG. 6) formed between the outer periphery 3S (accumulation recess 40) of the rotating drum 3 and the downstream edge (end) of the duct 51. Therefore, in this embodiment, when an air flow toward the accumulation recess 40 occurs in the duct 51, induced air flows into the duct 51 through the gap G, similar to the openings 52, 52. However, since the distance between the gap G and the surface of the accumulation recess 40 is even shorter than the distance between the openings 52, 52 and the surface of the accumulation recess 40, the induced air through the gap G hardly affects the flow of vacuum air in the duct 51.

In this embodiment, the number of openings 52 provided on each of a pair of opposing walls is two, but it may be one on each opposing wall, or three or more on each opposing wall.
In addition, in this embodiment, the shape of the opening 52 is a curved shape that follows the shape of the outer peripheral surface of the rotating drum 3 (accumulation recess 40), but it may be another shape, for example, a circular shape or a rectangular shape.
Furthermore, in this embodiment, for each of the multiple openings 52a, 52b, one opening and the other opening on the opposing wall surface are formed in symmetrical positions so as to face each other, but this is not limited to this, and for example, one opening and the other opening can also be formed so as to be shifted from each other in the supply direction of the raw material.

The shutter members 53 are provided for each of the openings 52a and 52b, and are capable of increasing or decreasing the opening area of each of the openings 52a and 52b. Specifically, the shutter members 53 are attached to the outer surface of the duct 51 via a slide mechanism (e.g., a rail member) and are configured to be able to slide (e.g., move up and down or left and right, or rotate) between a "closed position" in which the opening 52a (opening 52b) is closed and an "open position" in which the opening 52a (opening 52b) is opened. The material of the shutter members 53 is not particularly limited, and may be, for example, metal, synthetic resin, or a combination of these. The shutter members 53 may be configured to be manually slidable, or may be configured to be electrically slidable upon receiving an opening/closing command signal from a central processing unit (CPU) or the like. When the shutter members 53 are configured to be electrically slidable, they may be connected to a drive source (e.g., a motor or a solenoid) via a connecting member.

In this embodiment, by sliding the shutter member 53, the opening area of the pair of openings 52, 52 on the left and right sides (openings 52a, 52b on both sides in the drum width direction) can be increased or decreased, i.e., the amount of air induced into the duct 51 through each opening 52, 52 can be adjusted. For example, when the opening area of each opening 52, 52 is increased, the amount of induced air flowing into the duct 51 can be increased, and the convergence range of the air converging toward the center in the drum width direction can be narrowed (see Figures 6(a) and 7). This makes it possible to narrow, for example, the width in the lateral direction Y of the middle height portion 10A of the absorber 10 (see Figure 8(a)).

On the other hand, when the opening area of each opening 52, 52 is reduced, it is possible to reduce the amount of induced air flowing into the duct 51, and therefore the convergence range of the air converging toward the center of the drum width direction can be widened (see Figs. 6(a) and 7). This makes it possible, for example, to widen the width of the middle-height portion 10A of the absorbent body 10 in the lateral direction Y (see Fig. 8(a)). Note that the opening areas of the pair of left and right openings 52, 52 are not limited to being the same size, but can also be set to different sizes by appropriately adjusting the movement amount of the shutter member 53. In this case, since the convergence range of the air flowing in the duct 51 can be shifted to the right or left side in the drum width direction, for example, it is also possible to make the basis weight of one standard basis weight portion 11B in the lateral direction Y of the absorbent body 10 larger than the basis weight of the other standard basis weight portion 11B (see Fig. 8(a)). The opening area of each shutter member 53 can be increased or decreased using a drive source such as a motor that is driven by an opening/closing command signal from a central processing unit (CPU) or the like.

Here, the absorbent body 10 stacked by the fiber stacking device 1 will be described with reference to FIG. 8(a).
As shown in FIG. 8, the absorbent 10 manufactured using the fiber stacking device 1 can absorb aqueous liquids including body fluids. The use of the absorbent is not particularly limited, but it is particularly suitable as an absorbent for absorbent articles. The term "absorbent article" as used herein broadly includes articles used to absorb body fluids (urine, loose stool, menstrual blood, sweat, etc.) discharged from the human body, and includes, for example, disposable diapers, sanitary napkins, sanitary shorts, incontinence pads, etc. Absorbent articles typically include an absorbent, a liquid-permeable front sheet arranged closer to the wearer's skin than the absorbent, and a liquid-impermeable or impermeable back sheet arranged farther from the wearer's skin than the absorbent.

The absorbent body 10 is for an absorbent article, and has a vertical direction X corresponding to the front-to-back direction of a wearer of the absorbent article, and a horizontal direction Y perpendicular to the vertical direction X. The vertical direction X corresponds to the flow direction or machine direction, i.e., MD (Machine Direction), during the manufacture of the absorbent body 10, which will be described later, and the horizontal direction Y corresponds to CD (Cross Machine Direction), which is a direction perpendicular to the MD. The MD corresponds to the drum circumferential direction X1, which will be described later, or more specifically, the rotation direction R1 of the rotating drum 3, and the CD corresponds to the drum width direction Y1, which will be described later (see Figure 1).

The absorbent body 10 has a high basis weight section 11, in which the basis weight of the fiber material is relatively high, and a low basis weight section 12, in which the basis weight is relatively low, in one direction. The absorbent body 10 according to this embodiment has a long shape (approximately rectangular shape) in the vertical direction X in a plan view, with the high basis weight section 11 arranged in the center in the longitudinal direction, i.e., the vertical direction X, and the low basis weight sections 12 arranged at both ends in the vertical direction X, in the order of the low basis weight section 12, the high basis weight section 11, and the low basis weight section 12, arranged in the vertical direction X.

The high basis weight section 11 is a region including a portion in which the fiber material has a larger basis weight than the low basis weight section 12 in one direction (vertical direction X) in which the high basis weight section 11 and the low basis weight section 12 are connected, and if other portions other than the high basis weight section are included, the high basis weight section 11 includes both the high basis weight section 11A, which is the portion of the absorbent 10 with the largest basis weight of the fiber material, in the central portion in the horizontal direction Y (short direction) of the high basis weight section 11, and on both sides of the high basis weight section 11A in the horizontal direction Y, there are standard basis weight sections 11B, which have a smaller basis weight of the fiber material than the high basis weight section 11A, and the entire region consisting of the high basis weight section 11A and the standard basis weight section 11B (other portions in the vertical direction X and in the same position as the high basis weight section 11A) is the high basis weight section 11.

The central portion 11A is thicker than the peripheral portion, protrudes to one side of the absorbent body 10, and has a generally rectangular shape that is long in the vertical direction X in a plan view. The absorbent body 10 may be used with the protruding surface of the central portion 11A (the upper surface in FIG. 8 ) facing the skin of a wearer of an absorbent article in which the absorbent body 10 is used, or the surface opposite to the protruding surface of the central portion 11A may be used with the skin of the wearer.
The standard basis weight portion 11B may have a smaller basis weight of the fibrous material than the low basis weight portion 12.
The low basis weight portion 12 may have a uniform basis weight over its entire area, or may have a basis weight that varies partially.

In this embodiment, the high basis weight portion 11 and the low basis weight portion 12 are each divided into a plurality of regions by a plurality of groove-like recesses 13X, 13Y that are linear in plan view and intersect with each other. The groove-like recesses 13X extend in the vertical direction X, and the groove-like recesses 13Y extend in the horizontal direction Y. In the illustrated embodiment, the groove-like recesses 13X, 13Y are formed on the protruding surface (upper surface in FIG. 8 ) side of the central high portion 11A in the absorbent body 10, but may be formed on the surface opposite to the protruding surface side.
The groove-shaped recesses 13X and 13Y function as flow paths for liquids such as excrement, thereby improving the liquid absorption ability of the absorbent body 10, and also improve the softness and flexibility of the absorbent body 10, thereby improving the ability of the absorbent article to conform to the body of the wearer. Note that the groove-shaped recesses 13X and 13Y may be omitted.

Next, with reference to Figures 8(a) and 9, the basis weight of the absorbent body 10 formed when the shutter members 53 arranged in each of the pair of left and right openings 52, 52 are moved to the "closed position" and the basis weight of the absorbent body 10 formed when the shutter members 53 are moved to the "open position".
FIG. 9 is a graph showing test results comparing the basis weight of the absorbent body 10 formed when all shutter members 53 are moved to the "closed position" with the basis weight of the absorbent body 10 formed when all shutter members 53 are moved to the "open position."

As shown in Figures 8(a) and 9, in a test in which all of the shutter members 53 arranged in each of a pair of left and right openings 52, 52 were moved to the "closed position," an absorbent body 10 was produced in which the mid-high portion 11A had a basis weight of 279 g/ ^m2 , the standard basis weight portion 11B had a basis weight of 193 g/ ^m2 , and the low basis weight portion 12 had a basis weight of 112 g/ ^m2 .
In contrast, in a test in which all of the shutter members 53 were moved to the "open position," it was possible to produce an absorbent body 10 having a basis weight of 313 g/ ^m2 for the mid-high portion 11A, a basis weight of 150 g/ ^m2 for the standard basis weight portion 11B, and a basis weight of 119 g/ ^m2 for the low basis weight portion 12.

In other words, from the graph in Figure 9, it can be seen that when all of the shutter members 53 are moved from the "closed position" to the "open position", in the high basis weight section 11, the basis weight of the mid-height section 11A increases from "279 g/ ^m2 " to "313 g/m2 ^" , while the basis weight of the standard basis weight section 11B decreases from "193 g/ ^m2 " to "150 g/m2 ^" .
For example, from these test results, it can be seen that when all of the shutter members 53 are in the "open position," the induced air flowing in through the pair of left and right openings 52, 52 causes the air flowing inside the duct 51 to converge nicely toward the center of the drum width direction, and as a result, the raw materials contained in the air are (1) concentrated and stacked on the first recess bottom forming plate 34 (see Figures 4 and 6(a) etc.) located in the center of the accumulation recess 40 in the drum width direction, while (2) as a result, they are not stacked on the second recess bottom forming plates 36 located on both sides of the first recess bottom forming plate 34 in the drum width direction. In addition, in the second recess bottom forming plate 36 that forms the low basis weight section 12, by moving all of the shutter members 53 from the "closed position" to the "open position", the raw materials that converge toward the center of the drum width direction (center in the horizontal direction Y) are stacked well, resulting in an overall increase in basis weight of the low basis weight section 12 from "112 g/ ^m2 " to "119 g/ ^m2 ".
The above tests and their results are merely examples, and the configurations of the stack and absorbent body manufactured in the present invention are in no way limited to the above tests and their results.

In this way, in this embodiment, by increasing or decreasing the opening area of each of the pair of left and right openings 52, 52 by moving the shutter member 53, it is possible to stack (stacking) the raw materials well, aiming at the desired stacking position, such as the center of the drum width direction of the accumulation recess 40 (e.g., the first recess bottom forming plate 34).

In this embodiment, the vacuum air control methods are made different between the high basis weight portion priority stacking region S1 and the full-surface stacking region S2, so that the stacking methods of both regions S1, S2 are made different from each other (see Figure 2, etc.).
2 and 3, the outer periphery 2S of the fixed drum 2, which is the source (suction source) of the vacuum air, is provided with a selective suction region 23 corresponding to the region S1 and including a suction controller 25 partially having a controller opening 26, and a full suction region 24 corresponding to the region S2 and opening over the entire area of the portion corresponding to the accumulation recess 40. The outer periphery 3AS of the drum body 3A, which is the portion facing the outer periphery 2S of the fixed drum 2 in the rotating drum 3, is provided with a suction inhibition portion 31 including a non-permeable opening closing member 30 corresponding to the low basis weight portion corresponding to the accumulation recess 40, and a suction non-inhibition portion 32 corresponding to the high basis weight portion corresponding to the other portion of the accumulation recess 40, which does not include the opening closing member 30 and is made of a through hole penetrating the outer periphery 3AS in the thickness direction. When the rotating drum 3 rotates in the rotation direction R1 (see FIG. 1), the accumulation recess 40 moves through the fiber-stacking region S in the order of region S1 and region S2. FIG. 5 shows the suction state in regions S1 and S2 of the low basis weight portion corresponding portion 42, and FIG. 6 shows the suction state in regions S1 and S2 of the high basis weight portion corresponding portion 41. The arrows in FIG. 5 and FIG. 6 indicate the flow of air (vacuum air or induced air). FIG. 5(a) and FIG. 6(a) show the suction state in region S1 (selective suction region 23 of the outer periphery 2S of the fixed drum 2), and FIG. 5(b) and FIG. 6(b) show the suction state in region S2 (full suction region 24 of the outer periphery 2S of the fixed drum 2).

As shown in Figures 2 to 4, in the low basis weight section corresponding section 42, when the accumulation recess 40 is passing through the region S1, the opening closure member 30 of the rotating drum 3 overlaps with the control body opening 26 of the selective suction region 23 of the fixed drum 2, thereby closing the control body opening 26 (see Figure 5 (a)), but in the high basis weight section corresponding section 41, the control body opening 26 is not closed (see Figure 6 (a)).

Therefore, while the accumulation recess 40 is passing through the region S1, in the low basis weight section corresponding section 42, the vacuum air can hardly pass through the control body opening 26, so stacking of the fiber material does not actually occur. In contrast, in the high basis weight section corresponding section 41, the vacuum air can pass through the control body opening 26, so stacking of the fiber material occurs. In this way, in region S1, suction of the low basis weight section corresponding section 42 is selectively inhibited, while suction of the high basis weight section corresponding section 41 is permitted.

In this embodiment, as described above, a pair of openings 52, 52 are formed on the left and right sides of the duct 51 in the high basis weight section priority stacking region S1 (see FIG. 6(a)). Therefore, when the accumulation recess 40 passes through the high basis weight section priority stacking region S1, the flow direction of the vacuum air containing the raw material flowing through the duct 51 is changed by the induced air through the openings 52, 52, and the vacuum air flows toward the first recess bottom forming plate 34 located in the widthwise center of the accumulation recess 40 (see FIG. 6(a) and FIG. 7). As a result, in this embodiment, when the accumulation recess 40 passes through the high basis weight section priority stacking region S1, the raw material is effectively stacked in the high basis weight section corresponding portion 41.

On the other hand, when the accumulation recess 40 is passing through the region S2, the full suction region 24 of the fixed drum 2 corresponding to the region S2 does not include a non-breathable member such as the suction control body 25, and the entire area of the portion of the region 24 corresponding to the accumulation recess 40 is open, so that the fiber material can be sucked by vacuum air in both the low basis weight portion corresponding portion 42 and the high basis weight portion corresponding portion 41, and fiber stacking is performed (see Figures 5(b) and 6(b)).

In this way, in this embodiment, the control body opening 26 of the fixed drum 2 and the opening closing member 30 of the rotating drum 3 periodically overlap with the rotation of the rotating drum 3, and in the high basis weight section priority stacking area S1, which is a part of the stacking area S, only the flow of vacuum air related to the low basis weight section corresponding area 42 is selectively inhibited, thereby enabling concentrated stacking of fiber material in the high basis weight section corresponding area 41. As a result, in area S1, fiber material is preferentially stacked in the high basis weight section corresponding area 41. Typically, in area S1, fiber material is essentially stacked only in the high basis weight section corresponding area 41, and no fiber material is stacked at all in the low basis weight section corresponding area 42, or even if fiber material is stacked, it is an extremely small amount compared to the high basis weight section corresponding area 41.

Next, the scuffing roll 45 provided in the fiber stacking device 1 will be described with reference to Figs.
1 and 2, the fiber stacking device 1 includes a scuffing roll 45 disposed opposite to the outer circumferential portion 3S of the rotating drum 3, and is configured to scrape off the fiber material stacked in the high basis weight portion corresponding portion 41 and re-stacking the scraped fiber material in the low basis weight portion corresponding portion 42. In this regard, the configurations of the openings 52, 52 and shutter member 53 formed in the duct 51, the control body opening 26 of the fixed drum 2, and the opening closing member 30 of the rotating drum 3, etc., were intended to obtain an absorbent body 10 (see FIG. 8(a)) having a relatively large basis weight difference between the high basis weight portion 11 and the low basis weight portion 12, but the fiber stacking process of the fiber material using the scuffing roll 45 can be said to be intended mainly to improve the uniformity of the basis weight of the low basis weight portion 12 (see FIG. 8(a)) in the absorbent body 10.
In this embodiment, the scuffing roll 45 is disposed inside the duct 51 on the downstream side of the fiber-stacking area S in the flow direction MD, specifically, on the downstream side of the entire fiber-stacking area S2 in the flow direction MD.

Next, the manufacturing method of the absorbent body of the present invention will be described using as an example the manufacturing method of the absorbent body 10 (see FIG. 8(a)) using the above-mentioned fiber stacking device 1. Where no particular description is given of such a manufacturing method, the description of the above-mentioned fiber stacking device 1 applies as appropriate.

The manufacturing method of the absorbent body 10 using the fiber-stacking device 1 includes a raw material supplying step, an airflow adjusting step, and a fiber-stacking step.
As shown in Figures 1 and 2, the raw material supplying process is a process in which the rotating drum 3 is rotated around the outer periphery 2S of the fixed drum 2 while supplying the fibrous material in a scattered state to the outer periphery 3S of the rotating drum 3.

The airflow adjustment process is a process of adjusting the airflow generated in the duct 51 by suction from the inside of the rotating drum 3, by sliding the shutter member 53. Specifically, in this air volume adjustment process, the shutter member 53 is slid to increase or decrease the opening area of the pair of left and right openings 52, 52, thereby adjusting the amount of induced air flowing into the duct 51 through the openings 52.
As described above, when all the shutter members 53 are slid toward the "open position" to increase the opening area of the opening 52, the amount of induced air flowing into the duct 51 through the pair of left and right openings 52, 52 also increases, so that the air (vacuum air) flowing through the duct 51 changes direction to a direction converging toward the center of the duct width direction (convergence direction) after passing through the opening 52 (see FIGS. 6(a) and 7). On the other hand, when all the shutter members 53 are slid toward the "closed position", the amount of induced air flowing into the duct 51 through the pair of left and right openings 52, 52 decreases, so that the air flowing through the duct 51 changes direction to a direction opposite to the convergence direction (divergence direction) (see FIGS. 6(b) and 7).
For example, if the opening area of one of a pair of openings 52, 52 on the left and right sides is larger than that of the other opening 52, the amount of air induced through one opening 52 will be greater than the amount of air induced through the other opening 52, and the air (vacuum air) flowing inside the duct 51 will flow in a direction away from the center of the duct width toward one of the openings 52.

In the fiber-stacking process, the raw material transported by the air current is stacked in the accumulation recess 40. For example, when all the shutter members 53 are slid toward the "closed position", the raw material can be stacked in the accumulation recess 40 with the stacking range in the drum width direction narrowed, so that it is possible to form an absorbent body 10 with a narrower width in the lateral direction Y of the central portion 11A (see FIG. 8(b)). On the other hand, conversely, when all the shutter members 53 are slid toward the "closed position", it is possible to form an absorbent body 10 with a wider width in the lateral direction Y of the central portion 11A (see FIG. 8(a)).
Furthermore, when the shutter member 53 is moved so that the opening area of one of the pair of left and right openings 52, 52 is larger than the opening area of the other, it becomes possible to stack the raw material in a position (range) of the accumulation recess 40 that is closer to the one of the openings 52 from the center of the duct width direction.

The manufacturing method of the present invention, which has the above steps, allows the raw materials to be stacked (accumulated) at specific locations in the accumulation recess, making it possible to form (manufacture) an absorbent body 10 of the desired shape with consistent quality.

[Modification 1]
In the above embodiment, the multiple openings (openings 52a, 52b) constituting the opening 52 are arranged side by side along the outer circumferential portion 3S of the rotating drum 3, but instead, it is also possible to arrange them side by side along the supply direction.
Such a modified example will be described below with reference to Fig. 10. In the following, the same components as those in the above embodiment will be denoted by the same reference numerals and the description thereof will be omitted.

In this modification, a pair of openings 52', 52' are formed symmetrically in a pair of opposing wall surfaces of the duct 51 that face each other in the axial direction of the rotation shaft of the rotating drum 3, similar to the openings 52, 52 in the above embodiment. A plurality of openings 52' (two in the illustrated example) are formed in each of the pair of opposing wall surfaces in this modification, and the plurality of openings 52c, 52d are arranged in parallel along the supply direction d1 of the raw material in the duct 51. The opening 52c is formed at approximately the same position as the opening 52a (see FIG. 2, etc.) in the above embodiment, and is disposed downstream of the opening 52d in the supply direction d1.
As in the above embodiment, each of the openings 52c and 52d is provided with a shutter member 53 that can slide between a "closed position" that closes the opening and an "open position." In this modified example, an example in which "two" openings 52' are provided is shown, but it is also possible to provide "three" or more openings.

With this configuration, for example, when the vacuum air passes through the pair of left and right openings 52d, 52d with all the shutter members 53 in the "open position", it converges toward the center in the drum width direction, and then when it passes through the pair of left and right openings 52c, 52c, it further converges toward the center in the drum width direction. In other words, in this modified example, the raw material can be stacked in the accumulation recess 40 with the flow of the vacuum air being changed toward the center in the drum width direction in two stages.
In this way, according to this modified example, the flow of vacuum air can be changed in multiple stages by sliding the shutter member 53, making it possible to stack the raw material at a more targeted position in the accumulation recess 40.

[Modification 2]
In addition, in the above embodiment and modified example, the shutter member 53 is attached directly to each of the pair of left and right openings 52, 52 (openings 52', 52'). However, for example, as shown in FIG. 11, the shutter member 53 can also be provided on an auxiliary duct 54 arranged to cover the openings 52, 52.
Such a modified example will be described below. Fig. 11(a) shows a plan view of this modified example, and Fig. 11(b) shows a side view of this modified example. Note that, in the following, the same components as those in the above-described embodiments will be given the same reference numerals and their description will be omitted. Also, since the pair of left and right auxiliary ducts 54, 54 shown below have the same configuration, one of the auxiliary ducts 54 will be described and the description of the other auxiliary duct 54 will be omitted unless necessary.

As shown in Figures 11(a) and (b), in this modified example, a pair of openings 52, 52, each consisting of "one" opening 52a, is formed in a duct 51, and an auxiliary duct 54 (wind tunnel) that introduces induced air through the opening 52 is attached to the outer surface of the duct 51.
The auxiliary duct 54 extends at an acute angle to the opposite direction (counter-supply direction) to the raw material supply direction d1, and has an induced air intake 54a at its extended end for taking in induced air. The auxiliary duct 54 also has a shutter member 53 in its pipe that is movable between a "closed position" that blocks the flow of induced air and an "open position" that allows it.

With this configuration, the induced air can be caused to flow at an acute angle to the vacuum air flowing inside the duct 51, making it possible to prevent the generation of turbulence that can occur when the induced air flows into the duct 51. As a result, in this modified example, the flow direction of the vacuum air inside the duct 51 can be smoothly changed by the induced air without disturbing the flow of the vacuum air.

[Modification 3]
Furthermore, in the above embodiment and each modified example, induced air is introduced (flows into) duct 51 through opening 52 (opening 52'), but it is also possible to introduce air generated by an air supply device such as a fan or a device that generates compressed air (hereinafter referred to as "air supply").
With this configuration, when the fiber stacking device 1 is operated, it is possible to send the supply air generated by the air supply device into the duct 51 (air volume adjustment process). Therefore, in this modified example, a desired volume of supply air can be introduced into the duct 51, so that the flow of the vacuum air can be changed toward a desired position in the accumulation recess 40 without being influenced by the suction volume of the vacuum air flowing through the duct 51. Also, in this modified example, the introduction or stopping of supply air into the duct 51 can be performed by turning the air supply device ON/OFF, so that the shutter member 53 used in each of the above embodiments can be omitted.

When the above-mentioned air supply device is used, the generated air supply can be intermittently introduced into the duct 51 through the opening 52. In this case, by controlling the timing of the introduction of the air supply and the amount of air supply, it is possible to concentrate the raw material stacking at the center of the drum width direction of the high basis weight portion corresponding portion 41 of the accumulation recess 40, that is, to prevent the raw material from stacking at both ends of the drum width direction (see FIG. 7, etc.). As a result, for example, an absorbent body 10 can be formed in which the standard basis weight portion 11B is constricted, as shown in FIG. 8(b).

[Modification 4]
In the above embodiment and each modified example, the openings 52, 52 are formed on the opposing wall surfaces facing each other in the axial direction of the rotating shaft of the rotating drum 3, but in addition to this, openings 56, 56 can also be formed on the opposing wall surfaces facing each other in the cross direction (vertical direction) that crosses the axial direction of the rotating shaft (see FIG. 12). Note that, like the openings 52 in the axial direction (horizontal direction), the openings 56 in the cross direction (vertical direction) may be provided as a pair at a specific location in the supply direction of the raw materials in the duct 51, or a plurality of openings may be provided at intervals in the supply direction of the raw materials in the duct 51. Like the openings 52, the openings 56 can also be provided with a shutter member 57 that can move between a "closed position" that closes the opening and an "open position" that opens the opening (see FIG. 12).
With this configuration, the flow direction of the vacuum air circulating within the duct 51 can be changed not only in the drum width direction, but also in the vertical direction (for example, downward in the example shown in Figure 12), making it possible to stack the raw material at a more targeted position in the accumulation recess 40.

When a pair of upper and lower openings 56, 56 are formed in the duct 51, it is possible to configure it in the same manner as in the above-mentioned modified examples 1 to 4. Specifically, (1) the opening 56 may be configured with a plurality of openings arranged in parallel along the supply direction (corresponding to modified example 1, see FIG. 10), (2) an auxiliary duct as shown in FIG. 11 (see "auxiliary duct 54") may be attached to the opening 56 (corresponding to modified example 2), and (3) the supply air generated by the air supply device may be introduced into the duct 51 through the opening 56 (corresponding to modified example 3).

[Modification 5]
Furthermore, as a modified example of the fiber-stacking device 1, a pair of partition plates can be provided inside the duct 51 in the fiber-stacking area S, as described in, for example, JP 2015-126872 A.
When such a pair of partition plates 43, 43 are provided in the duct 51, they may be fixed to the ring plate 38 forming the outer surface of the rotating drum 3 (see FIG. 3, etc.) and disposed on both sides of the accumulation recess 40 in the drum width direction (see FIG. 13). For example, as in JP 2015-126872 A, the pair of partition plates 43, 43 are preferably formed to have a substantially triangular cross section, and the opposing surfaces are preferably inclined so that the distance between them gradually narrows toward the rotating drum 3. With this configuration, in the accumulation recess 40, raw materials such as stacking material can be supplied intensively to the center of the drum axial direction, while supply to both ends of the drum width direction can be physically hindered.
When such a pair of partition plates 43, 43 are provided in the duct 51, the opening 52 and the shutter member 53 may be formed on the upstream side of the partition plate 43 in a side view, as shown in Fig. 13. Of course, the opening 52 and the shutter member 53 may also be provided on the downstream side of the partition plate 43 in a side view.
In this way, by providing the duct 51 with a pair of openings 52, 52, a shutter member 53, and a pair of partition plates 43, 43, it becomes possible to further concentrate and stack the raw material in the center of the accumulation recess 40 in the drum width direction.

In relation to the above-mentioned embodiment, the present invention further discloses the following apparatus and method.
＜1＞
A rotating drum having an accumulation recess formed on its outer circumferential surface;
A duct for supplying raw material to the outer peripheral surface,
A fiber stacking device that stacks the raw materials in the accumulation recess by conveying the raw materials with an air flow generated in the duct by suction from the inside of the rotating drum while rotating the rotating drum around a rotation axis,
The duct is
a pair of opposing wall surfaces opposed to each other in the axial direction of the rotating shaft each have an opening that opens at a position spaced from a downstream edge adjacent to the rotating drum; and
The fiber stacking device, wherein the duct is provided with a control mechanism for controlling the amount of air flowing into the duct through the opening.
＜2＞
The fiber stacking device according to <1>, wherein the control mechanism includes an opening/closing member that is movable between a closed position that closes the opening and an open position that opens the opening.
＜3＞
The fiber stacking device according to <1> or <2>, wherein a distance between the opening and an outer periphery of the rotating drum is 5 mm or more and 100 mm or less.
＜4＞
The fiber stacking device according to any one of <1> to <3>, wherein the opening has a curved shape that conforms to the outer circumferential surface of the rotating drum.
＜5＞
A plurality of the openings are formed in each of the pair of opposing wall surfaces,
The fiber stacking device according to any one of <1> to <4>, wherein the plurality of openings are arranged side by side along the circumferential direction of the rotating drum.
＜6＞
A plurality of the openings are formed in each of the pair of opposing wall surfaces,
The fiber stacking device according to any one of <1> to <5>, wherein the plurality of openings are arranged side by side along a supply direction of the raw material in the duct.
＜７＞
The fiber stacking device according to any one of <1> to <6>, further comprising an auxiliary duct connected to the opening, the auxiliary duct extending at an acute angle with respect to a direction opposite to a supply direction of the raw material in the duct.
＜8＞
The fiber stacking device according to any one of <1> to <7>, further comprising an air supply device that forcibly sends an air flow into the duct through the opening.

＜9＞
The duct is
a second opening portion that opens in each of the opposing wall surfaces that face each other in a direction intersecting the axial direction of the rotation shaft;
The fiber stacking device described in any one of <1> to <8>, further comprising a second control mechanism that controls an amount of air flowing in from the second opening.
＜10＞
The fiber stacking device described in <9> is provided with a second auxiliary duct connected to the second opening, and the second auxiliary duct extends at an acute angle to a direction opposite to the supply direction of the raw material in the duct.
<11>
The fiber stacking device according to <9> or <10>, further comprising an air supply device that forcibly sends an air flow into the duct through the second opening.
＜12＞
The fiber stacking device according to <8> or <11>, wherein the air supply device is configured to intermittently send an air flow into the duct.
＜13＞
The rotating drum is configured to stack the raw material in the accumulation recess in a predetermined stacking region in the drum circumferential direction,
the accumulation recess has a high basis weight portion corresponding portion that forms a high basis weight portion in which the basis weight of the raw material is relatively high, and a low basis weight portion corresponding portion that forms a low basis weight portion in which the basis weight of the raw material is relatively low, in a drum circumferential direction;
The fiber-stacking region has a high-basis-weight-part preferential fiber-stacking region in which the raw material is preferentially stacked in the portion corresponding to the high-basis-weight part, and a full-surface fiber-stacking region in which the fiber material is stacked in both the portion corresponding to the high-basis-weight part and the portion corresponding to the low-basis-weight part, in the drum circumferential direction;
The fiber stacking device according to any one of <1> to <12>, wherein the control mechanism is provided in the duct adjacent to the high basis weight portion preferential fiber stacking region.
＜14＞
The fiber stacking device further includes a scuffing roll disposed opposite the outer periphery of the rotating drum and configured to scrape off excess stacked raw material,
The fiber stacking device according to any one of <1> to <13>, wherein the scuffing roll is arranged inside the duct on the downstream side of the rotation direction of the rotating drum (the "full fiber stacking area").

＜15＞
A method for manufacturing an absorbent body using a fiber stacking device,
The fiber stacking device is
a rotating drum having an accumulation recess formed on an outer circumferential surface thereof and rotating about a rotation axis;
A duct for supplying raw material to the outer peripheral surface,
The duct is
a pair of opposing wall surfaces opposed to each other in the axial direction of the rotating shaft each have an opening that opens at a position spaced from a downstream edge adjacent to the rotating drum; and
a control mechanism is provided in the duct to control an amount of air flowing into the duct through the opening,
The manufacturing method includes:
a raw material supplying step of supplying raw material to the duct while rotating the rotary drum around a rotation axis;
an airflow adjusting step of adjusting the airflow generated in the duct by suction from the inside of the rotating drum by controlling the control mechanism;
and a fiber-stacking step of stacking the raw material transported by the air flow in the accumulation recess.
＜16＞
The fiber stacking device includes an air supply device that forcibly supplies air into the duct through the opening,
The method for manufacturing an absorbent body according to <15>, wherein the air flow adjusting step includes a step of adjusting the air flow generated in the duct by controlling the air supply device.
＜１７＞
The method for manufacturing an absorbent body according to <16>, wherein the air flow adjusting step includes a step of intermittently feeding an air flow into the duct by controlling the air supply device.
＜18＞
The rotating drum is configured to stack the raw material in the accumulation recess in a predetermined stacking region in the drum circumferential direction,
the accumulation recess has a high basis weight portion corresponding portion that forms a high basis weight portion in which the basis weight of the raw material is relatively high, and a low basis weight portion corresponding portion that forms a low basis weight portion in which the basis weight of the raw material is relatively low, in a drum circumferential direction;
The fiber-stacking region has a high basis weight portion preferential fiber-stacking region in the drum circumferential direction, which preferentially stacks the raw material in the high basis weight portion corresponding portion,
The control mechanism is provided in the duct adjacent to the high basis weight portion preferential fiber-stacking region,
The method for manufacturing an absorbent body according to any one of <15> to <17>, wherein the fiber-stacking step includes a step of preferentially stacking the raw material transported by the air flow in the portion corresponding to the high basis weight portion.
＜19＞
The manufacturing method of the absorbent body according to any one of <15> to <18> further includes a restacking step of scraping off the excess stacked raw material using a scuffing roll arranged opposite to the outer circumferential surface of the rotating drum after the stacking step, and restacking the scraped molded body material.

1 Fiber stacking device 2 Fixed drum 2S Fixed drum outer periphery 10, 10' Absorbent body 11 High basis weight portion 11A Mid-height portion 11B Standard basis weight portion 12, 12A, 12B Low basis weight portion 13X, 13Y Groove-shaped recess 21 Side wall 22 Partition wall 23 Selective suction area 24 Full suction area 25 Suction control body 26 Control body opening 3 Rotating drum 3A Drum body 30 Opening closing member 31 Suction inhibition portion 32 Suction non-inhibition portion 3B Outer layer portion 34 First recess bottom forming plate 36 Second recess bottom forming plate 37 Recess partition plate 38 Ring plate 4 Accumulation portion 40 Accumulation recess 41 High basis weight portion corresponding portion 42 Low basis weight portion corresponding portion 43 Partition plate 45 Scuffing roll 5 Raw material supply mechanism 51 Duct 52, 52', 56 Openings 52a to 52d Openings 53, 57 Shutter member 54 Auxiliary duct 54a Induction air intake 6 Conveyor mechanism S Fiber-stacking area S1 High basis weight portion preferential fiber-stacking area S2 Full-surface fiber-stacking area X1 Drum circumferential direction R1 Rotation direction of rotating drum (MD)
Y1 Drum width direction (CD)
X Vertical direction Y Horizontal direction D Distance G Gap

Claims (14)

A rotating drum having an accumulation recess formed on its outer circumferential surface;
A duct for supplying raw material to the outer peripheral surface,
A fiber stacking device that rotates the rotating drum around a rotation axis, transports the raw materials using an air flow generated in the duct by suction from the inside of the rotating drum , and forms an absorbent body, which is a stack of the raw materials, in the accumulation recess,
The absorber has a lateral direction corresponding to the width direction of the rotating drum,
The absorbent body has a central peak and portions located on both sides of the central peak in the lateral direction and having a smaller basis weight of the raw material than the central peak,
The duct is
a pair of opposing wall surfaces opposed to each other in the axial direction of the rotating shaft each have an opening that opens at a position spaced from a downstream edge adjacent to the rotating drum; and
a control mechanism is provided in the duct to control an amount of air flowing into the duct through the opening,
The control mechanism is a mechanism that changes the flow of the air flow transporting the raw material toward the center of the width direction of the rotating drum by the air flowing into the duct through the opening . The fiber stacking device according to claim 1, wherein the control mechanism includes an opening/closing member that can move between a closed position that closes the opening and an open position that opens the opening. The fiber stacking device according to claim 1 or 2, wherein the distance between the opening and the outer periphery of the rotating drum is 5 mm or more and 100 mm or less. The fiber stacking device according to claim 1 , wherein the opening has a curved shape that conforms to the outer circumferential surface of the rotating drum. A plurality of the openings are formed in each of the pair of opposing wall surfaces,
The fiber stacking device according to claim 1 , wherein the plurality of openings are arranged side by side along a circumferential direction of the rotating drum. A plurality of the openings are formed in each of the pair of opposing wall surfaces,
The fiber stacking device according to claim 1 , wherein the plurality of openings are arranged side by side along a supply direction of the raw material in the duct. The fiber stacking device according to claim 1 , further comprising an auxiliary duct connected to the opening, the auxiliary duct extending at an acute angle with respect to a direction opposite to a supply direction of the raw material in the duct. The fiber stacking device according to claim 1 , further comprising an air supply device that forcibly supplies air flow into the duct through the opening. The fiber stacking device according to claim 2 , wherein the opening and closing members are provided for each of the openings. The rotating drum is configured to stack the raw material in the accumulation recess in a predetermined stacking region in a drum circumferential direction,
the accumulation recess has a high basis weight portion corresponding portion that forms a high basis weight portion in which the basis weight of the raw material is relatively high, and a low basis weight portion corresponding portion that forms a low basis weight portion in which the basis weight of the raw material is relatively low, in a drum circumferential direction;
The fiber-stacking region has a high-basis-weight-part preferential fiber-stacking region in which the raw material is preferentially stacked in the high-basis-weight-part corresponding region, and a full-surface fiber-stacking region in which the fiber material is stacked in both the high-basis-weight-part corresponding region and the low-basis-weight-part corresponding region, in the drum circumferential direction;
The fiber stacking device according to claim 1 , wherein the control mechanism is provided in the duct adjacent to the high basis weight portion preferential fiber stacking region. A method for manufacturing an absorbent body using a fiber stacking device,
The absorbent body has a central peak and portions located on both sides of the central peak in the lateral direction and having a smaller basis weight of raw material than the central peak,
The fiber stacking device is
a rotating drum having an accumulation recess formed on an outer circumferential surface thereof and rotating about a rotation axis;
A duct for supplying raw material to the outer peripheral surface,
The lateral direction of the absorber corresponds to the width direction of the rotating drum,
The duct is
a pair of opposing wall surfaces opposed to each other in the axial direction of the rotating shaft each have an opening that opens at a position spaced from a downstream edge adjacent to the rotating drum; and
a control mechanism is provided in the duct to control an amount of air flowing into the duct through the opening,
the control mechanism is a mechanism for changing a flow of the air flow conveying the raw materials toward a center in a width direction of the rotating drum by the air flowing into the duct through the opening,
The manufacturing method includes:
a raw material supplying step of supplying the raw material to the duct while rotating the rotary drum around a rotation axis;
an airflow adjusting step of adjusting the airflow generated in the duct by suction from the inside of the rotating drum by controlling the control mechanism;
and a fiber-stacking step of stacking the raw material transported by the air flow in the accumulation recess. The fiber stacking device includes an air supply device that forcibly supplies air into the duct through the opening,
The method for manufacturing an absorbent body according to claim 11 , wherein the air flow adjusting step includes a step of adjusting the air flow generated in the duct by controlling the air supply device. The method for manufacturing an absorbent body according to claim 12 , wherein the air flow adjusting step includes a step of intermittently feeding an air flow into the duct by controlling the air supply device. The rotating drum is configured to stack the raw material in the accumulation recess in a predetermined stacking region in a drum circumferential direction,
the accumulation recess has a high basis weight portion corresponding portion that forms a high basis weight portion in which the basis weight of the raw material is relatively high, and a low basis weight portion corresponding portion that forms a low basis weight portion in which the basis weight of the raw material is relatively low, in a drum circumferential direction;
The fiber-stacking region has a high basis weight portion preferential fiber-stacking region in the drum circumferential direction, which preferentially stacks the raw material in the portion corresponding to the high basis weight portion,
The control mechanism is provided in the duct adjacent to the high basis weight portion preferential fiber-stacking region,
The method for manufacturing an absorbent body according to claim 11 , wherein the fiber-stacking step includes a step of preferentially stacking the raw material transported by the air flow in the portion corresponding to the high basis weight portion.

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