Patent Publication Number: US-2022218534-A1

Title: Composite stretchable member manufacturing apparatus

Description:
TECHNICAL FIELD 
     The present invention relates to a manufacturing apparatus for manufacturing a composite stretchable member. 
     BACKGROUND ART 
     Wearing articles such as a disposable diaper having a waistline portion and a crotch portion have been known. In the wearing article such as the disposable diaper, the waistline portion of the wearing article may be formed of a composite stretchable member, which is stretchable, to improve wearing comfort. 
     As an apparatus for manufacturing a composite stretchable member, for example, an apparatus described in Patent Literature 1 is known. 
     The apparatus described in Patent Literature 1 perforns welding processing with an elastically stretchable member sandwiched between two sheets made of a nonwoven fabric or the like by feeding these two sheets and the elastically stretchable member to a nip between an ultrasonic welding horn and an anvil roll for conveying sheets. 
     The anvil roll is provided on its outer periphery with a seal pattern protruding section, and a welding portion is formed on each of the two sheets corresponding to the seal pattern protruding section. The seal pattern protruding section is provided with a groove formed corresponding to a portion where the elastically stretchable member is disposed. The groove has a depth that is set to cause a part of the elastically stretchable member to protrude from the groove when the elastically stretchable member is inserted into the groove. 
     Inserting a part of the elastically stretchable member into the groove reduces pressure for sandwiching the elastically stretchable member when the two sheets and the elastically stretchable member are ultrasonically welded while being sandwiched between the ultrasonic welding horn and the seal pattern protruding section of the anvil roll. This enables the two sheets and the elastically stretchable member to be welded without cutting the elastically stretchable member. 
     Thus, welding the elastically stretchable member to two sheets without cutting the elastically stretchable member requires the elastically stretchable member to be prevented from being detached from the groove of the seal pattern protruding section. For this reason, the apparatus described in Patent Literature 1 is provided with a guide member upstream of the anvil roll in a direction of supplying the elastically stretchable member to the anvil roll. The guide member is disposed away from an outer peripheral surface of the anvil roll, and guides the elastically stretchable member into the groove of the seal pattern protruding section on the anvil roll. 
     The apparatus of Patent Literature 1 is configured to guide the elastically stretchable member into the groove of the seal pattern protruding section on the anvil roll using the guide member, and the elastically stretchable member may be detached from the groove due to influence of vibration of the apparatus or the like. This requires to improve a function of preventing cutting by reducing a defect in which the elastically stretchable member is detached from the groove. 
     CITATION LIST 
     Patent Literature 
     Patent Literature 1: International Publication WO 2016/208502 A 
     SUMMARY OF INVENTION 
     It is an object of the present invention to provide a manufacturing apparatus for manufacturing a composite stretchable member capable of improving a function of preventing cutting by reducing a defect in which an elastic member is detached from a groove of a conveying roller. 
     To solve the problem above, a manufacturing apparatus for manufacturing a composite stretchable member according to the present invention is configured to bond two sheets to each other and bond the sheets to multiple elastic members while conveying each of the sheets in a longitudinal direction to manufacture a composite stretchable member including the two sheets, and the multiple elastic members sandwiched between the two sheets, the manufacturing apparatus for manufacturing a composite stretchable member including: a bonding device that welds and bonds the multiple elastic members to the two sheets, and the two sheets to each other, while the multiple elastic members are sandwiched between the two sheets being conveyed; and a guide device that guides the two sheets and the multiple elastic members to the bonding device in such a manner that each of the multiple elastic members extends in a longitudinal direction thereof and is sandwiched between the two sheets, the bonding device having: a conveying roller that has an outer peripheral surface used for conveying the two sheets sandwiching the multiple elastic members in the longitudinal direction of each of the two sheets and that rotates about an axis predetermined; and a compressing device that faces the outer peripheral surface of the conveying roller to compress the two sheets sandwiching the multiple elastic members between the outer peripheral surface of the conveying roller and the compressing device, the bonding device is configured to apply heat to the two sheets between the conveying roller and the compressing device, the outer peripheral surface of the conveying roller is provided with at least one protruding section formed protruding radially outward from the outer peripheral surface, the at least one protruding section includes multiple grooves extending in a conveying direction of the conveying roller and is away from each other in a direction parallel to the axis, the guide device having a guide member provided with a leading end closest to the outer peripheral surface of the conveying roller, the leading end being provided with the multiple guide grooves that hold the corresponding multiple elastic members, while being away from each other in a direction parallel to the axis of the conveying roller, to guide the multiple elastic members into the corresponding multiple grooves of the conveying roller, and the guide member being disposed to allow each of the multiple elastic members positioned between the guide grooves and the corresponding grooves of the conveying roller to have a length of 30 mm or less. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1  is a plan view of a composite stretchable member manufactured by a manufacturing apparatus according to an embodiment of the present invention. 
         FIG. 2  is a part of a sectional view taken along line II-II in  FIG. 1 . 
         FIG. 3  is a schematic sectional view illustrating a section of an elastic member. 
         FIG. 4  is a view corresponding to  FIG. 1  and schematically illustrating a bonding section. 
         FIG. 5  is an enlarged view of a part of  FIG. 1 . 
         FIG. 6  is a schematic view illustrating a configuration of a manufacturing apparatus for manufacturing a composite stretchable member according to an embodiment of the present invention. 
         FIG. 7  is a plan view of the guide plate of  FIG. 6 . 
         FIG. 8  is a side view of the guide plate of  FIG. 7 . 
         FIG. 9  is an enlarged view of a guide groove of the guide plate of  FIG. 7 . 
         FIG. 10A  is an enlarged view of the guide plate and a peripheral portion thereof of the manufacturing apparatus of  FIG. 6 , and  FIG. 10B  is an enlarged view of a portion where an elastic member is fed from a guide groove of the guide plate of  FIG. 10A  to an anvil roll. 
         FIG. 11  is a view illustrating an outer peripheral surface of the anvil roll of  FIG. 6 . 
         FIG. 12  is an enlarged view illustrating protruding sections and grooves on the outer peripheral surface of the anvil roll in  FIG. 11 . 
         FIG. 13  is a sectional view taken along line XIII-XIII in  FIG. 12 . 
         FIG. 14  is a sectional view taken along line XIV-XIV in  FIG. 12 . 
         FIG. 15  is a developed view of a disposable diaper using a composite stretchable member. 
         FIG. 16  is a view schematically illustrating stages  1  to  3  for illustrating a method for manufacturing the disposable diaper illustrated in  FIG. 15 . 
         FIG. 17  is a view illustrating a manufacturing apparatus according to a modification of the present invention, being configured such that a guide plate is movable between a position close to an anvil roll and a position away from the anvil roll, and is a view illustrating a state in which the guide plate is at the position close to the anvil roll (position during operation of the manufacturing apparatus). 
         FIG. 18  is a view illustrating a state in which the guide plate of  FIG. 17  is at the position away from the anvil roll (a position when an elastic member such as a rubber thread is allowed to pass). 
     
    
    
     DESCRIPTION OF EMBODIMENTS 
     Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. The following embodiments are merely examples embodying the present invention, and do not limit the technical scope of the present invention. 
     (1) Configuration of Composite Stretchable Member 
       FIG. 1  is a plan view of a composite stretchable member manufactured by a manufacturing apparatus according to an embodiment of the present invention.  FIG. 2  is a part of a sectional view taken along line II-II in  FIG. 1 . 
     A composite stretchable member  1  includes two elongated sheets  2   a ,  2   b  facing each other, and multiple elongated elastic members  10  stretchable in a longitudinal direction A. Each of the elastic members  10  is disposed between the sheets  2   a ,  2   b  so as to be stretchable in the longitudinal direction A (the left-right direction in  FIG. 1 ) of each of the sheets  2   a ,  2   b , i.e., so as to extend and contract in the longitudinal direction A of each of the sheets  2   a ,  2   b  along the longitudinal direction A. In the present embodiment, the elastic members  10  are disposed at equal intervals in a width direction B (a direction orthogonal to the longitudinal direction A of the sheets  2   a ,  2   b ) of the sheets  2   a ,  2   b , and extend parallel to the longitudinal direction A of the sheets  2   a ,  2   b.    
     In the present embodiment, a sheet-like material such as a nonwoven fabric is used as the sheets  2   a ,  2   b.    
     An elastic member  10  is made of a material that is more elastic than the material (nonwoven fabric or the like) of the sheets  2   a ,  2   b , and the material of the elastic member  10  is not particularly limited in the present invention. As an example of the present embodiment is illustrated in  FIG. 3 , the elastic member  10  is a multi-strand provided with multiple rubber threads (fibrous elastic bodies)  10   a  collected in a bundle, and includes at least some of the rubber threads  10   a  each having the periphery covered with a covering layer  10   b , for example. Specifically, the rubber threads  10   a  disposed particularly in an outer peripheral portion among the multiple rubber threads  10   a  are each covered with the covering layer  10   b . Every rubber thread  10   a  may be covered with the covering layer  10   b.    
     Examples of the material of the rubber thread  10   a  include polyurethane. Examples of the material of the covering layer  10   b  include a lubricant such as silicon oil or magnesium stearate. 
       FIG. 1  illustrates a bonding section  4  in a lattice shape on which the sheets  2   a ,  2   b  are bonded to each other, and the sheets  2   a ,  2   b  are bonded to the elastic members  10 . 
       FIG. 4  schematically illustrates the bonding section of  FIG. 1 . As illustrated in  FIGS. 1 and 4 , the bonding section  4  includes multiple first bonding portions  4   a  and multiple second bonding portions  4   b.    
     The first bonding portions  4   a  are disposed at equal intervals in the longitudinal direction A of the sheets  2   a ,  2   b , and extend parallel to each other in the width direction B of the sheets  2   a ,  2   b.    
     The second bonding portions  4   b  are also disposed at equal intervals in the longitudinal direction A of the sheets  2   a ,  2   b , and extend parallel to each other in the width direction B of the sheets  2   a ,  2   b . The second bonding portions  4   b  extend intersecting the corresponding first bonding portions  4   a , thereby forming the bonding section  4  in a lattice shape. 
     In the present embodiment, both a first bonding portion  4   a  and a second bonding portion  4   b  are inclined with respect to the width direction B of the sheets  2   a ,  2   b . The inclination angle is smaller than 45 degrees. For example, the inclination angle is set to 30 degrees. 
     The first bonding portion  4   a  and the second bonding portion  4   b  each have a symmetrical shape with respect to both straight lines extending in the longitudinal direction A and the width direction B of the sheets  2   a ,  2   b . The first bonding portions  4   a  and the second bonding portions  4   b  are disposed such that a clearance between two adjacent first bonding portions  4   a  is equal to a clearance between two adjacent second bonding portions  4   b . This causes the bonding section  4  to have multiple defined rhombuses each having diagonals extend along the longitudinal direction A and the width direction B of the sheets  2   a .  2   b . As described above, the first bonding portion  4   a  and the second bonding portion  4   b  are each inclined with respect to the width direction B of the sheets  2   a ,  2   b  at an angle smaller than 45 degrees, and thus the first bonding portion  4   a  and the second bonding portion  4   b  form a rhombus extending in the width direction B. Intersections  4   c  between the first bonding portions  4   a  and the corresponding second bonding portions  4   b , which may be referred to below as bonding-portion side intersections, are arranged at equal intervals on a straight line extending in the longitudinal direction A of the sheets  2   a ,  2   b , and are arranged at equal intervals on a straight line extending in the width direction B of the sheets  2   a ,  2   b.    
     Each bonding section  4  intersects all the elastic members  10  and extends along a line intersecting an extending direction (i.e., the longitudinal direction A) of the elastic members  10 . Specifically, each bonding section  4  extends between opposite outer portions of the sheets  2   a ,  2   b  in the width direction B across a region where the elastic members  10  are disposed. 
     Each of the elastic members  10  and the bonding section  4  intersect at a portion excluding the bonding-portion side intersection  4   c , i.e., at a position away from the bonding-portion side intersection  4   c , and each of the elastic members  10  is bonded to the sheets  2   a ,  2   b  at this position. 
     With reference to  FIG. 5  that is an enlarged view of a part of  FIG. 1 , the configuration will be specifically described. 
     Each elastic member  10  is disposed passing through between two adjacent bonding-portion side intersections  4   c  on each first bonding portion  4   a  (e.g., between a bonding-portion side intersection  4   c _ 1  and a bonding-portion side intersection  4   c _ 2 , and between a bonding-portion side intersection  4   c _ 2  and a bonding-portion side intersection  4   c _ 3  illustrated in  FIG. 5 ). That is, a first elastic-member side intersection  4   d , which is an intersection between each elastic member  10  and the corresponding one of the first bonding portions  4   a , is positioned between two adjacent bonding-portion side intersections  4   c  on the first bonding portion  4   a , and the elastic member  10  is bonded to the sheets  2   a ,  2   b  at this position  4   d.    
     Similarly, each elastic member  10  is disposed passing through between adjacent bonding-portion side intersections  4   c  on each second bonding portion  4   b  (e.g., between a bonding-portion side intersection  4   c _ 4  and a bonding-portion side intersection  4   c _ 2 , and between a bonding-portion side intersection  4   c _ 2  and a bonding-portion side intersection  4   c _ 5  illustrated in  FIG. 5 ). That is, a second elastic-member side intersection  4   e , which is an intersection between each elastic member  10  and the corresponding one of the second bonding portions  4   b , is positioned between two adjacent bonding-portion side intersections  4   c  on the second bonding portion  4   b , and the elastic member  10  is bonded to the sheets  2   a ,  2   b  at this position  4   e.    
     In the present embodiment, each elastic member  10  passes through the center of the adjacent bonding-portion side intersections  4   c  and  4   c  on each first bonding portion  4   a , and the center of the adjacent bonding-portion side intersections  4   c  and  4   c  on each second bonding portion  4   b , and intersects the first bonding portion  4   a  and the second bonding portion  4   b  at the center position to be bonded to the sheets  2   a ,  2   b.    
     This causes the first elastic-member side intersection  4   d  and the second elastic-member side intersection  4   e  to be alternately arranged on a straight line extending in the width direction B of both the sheets  2   a ,  2   b . Intersections between the respective elastic members  10  and the bonding section  4 , i.e., bonding points  4   d  and  4   e  between the elastic members  10  and the sheets  2   a ,  2   b  are disposed at equal intervals in the longitudinal direction A of the sheets  2   a ,  2   b.    
     In the bonding section  4 , the sheets  2   a ,  2   b  as well as the sheets  2   a ,  2   b  and the elastic member  10  are bonded to each other by welding. In the present embodiment, these are ultrasonically welded. 
     The sheets  2   a ,  2   b  are bonded to each other by being partially melted and welded. In contrast, the elastic member  10  and the sheets  2   a ,  2   b  are welded to each other when the sheets  2   a ,  2   b  are partially melted and the covering layer  10   b  of the elastic member  10  is melted. 
     Specifically, in the present embodiment, a rubber thread having a melting point of about 200° C. is used as the rubber thread  10   a , and the covering layer  10   b  is made of magnesium stearate (melting point: about 120° C.) having a lower melting point than the rubber thread. When the elastic member  10  and the sheets  2   a ,  2   b  are welded to each other, the covering layer  10   b  is melted to weld the covering layer  10   b  to the sheets  2   a ,  2   b  without melting of the rubber thread  10   a.    
     (2) Manufacturing Apparatus for Manufacturing a Composite Stretchable Member 
     Next, a manufacturing apparatus for manufacturing the composite stretchable member  1  will be described. 
       FIG. 6  is a schematic view of a manufacturing apparatus  100  according to an embodiment of the present invention. 
     The manufacturing apparatus  100  includes: a bonding device  200  that ultrasonically welds and bonds the elastic member  10  to the sheets  2   a ,  2   b , and the sheets  2   a ,  2   b  to each other while the elastic member  10  is sandwiched between the sheets  2   a ,  2   b ; a first guide roller  102  that guides the sheet  2   a  to the bonding device  200  (specifically, an anvil roll  210  described later); an elastic member guide device (guide device)  110  that supplies the elastic member  10  to the bonding device  200 ; a nip roll (second guide roller)  104  that guides the sheet  2   b  to the bonding device  200  and presses the two sheets  2   a ,  2   b , and the elastic member  10 ; and a third guide roller  106  that guides a bonded sheet or the like, i.e., the composite stretchable member  1 . 
     The bonding device  200  includes the anvil roll (conveying roller)  210  and a horn (compressing device)  220 . 
     The anvil roll  210  is a rotating member that rotates about an axis extending in a direction orthogonal to the paper surface of  FIG. 6 . Hereinafter, the direction orthogonal to the paper surface of  FIG. 6  is referred to as a “front-back direction”. The anvil roll  210  is rotatably attached to a rotation shaft, as a rotation center, extending horizontally with respect to a vertical wall portion of an apparatus, such as a panel (not illustrated). The anvil roll  210  rotates to convey the elastic member  10  guided by the elastic member guide device  110  while the elastic member  10  is sandwiched between the sheets  2   a ,  2   b  guided by the rollers  102  and  104 , respectively, on the outer peripheral surface of the anvil roll  210 . In the example illustrated in  FIG. 6 , the anvil roll  210  rotates counterclockwise in  FIG. 6 . Hereinafter, the sheets  2   a ,  2   b  sandwiching the elastic member  10  may be referred to as pre-bonding sheets. 
     As illustrated in  FIG. 11 , the outer peripheral surface of the anvil roll  210  is provided with a protruding section  212  protruding radially outward. The protruding section  212  is provided on the outer peripheral surface of the anvil roll  210  throughout the outer peripheral surface in its circumferential direction. The protruding section  212  has a shape corresponding to that of the bonding section  4 . In the present embodiment, the bonding section  4  has a rhombic lattice shape as described above, and the protruding section  212  has a rhombic lattice shape correspondingly. 
     Specifically, the protruding section  212  includes first protruding portions  212   a  for forming the first bonding portions  4   a  and second protruding portions  212   b  for forming the second bonding portions  4   b.    
     The first protruding portions  212   a  extend along a direction (first direction C 1 ) intersecting the circumferential direction of the anvil roll  210  (conveying direction of the anvil roll  210 ), i.e., along a line intersecting the circumferential direction, and are disposed parallel to each other at equal intervals in the circumferential direction. The second protruding portions  212   b  extend along a direction (second direction C 2 ) intersecting the circumferential direction of the anvil roll  210  and the first direction C 1 , i.e., along a line intersecting the circumferential direction, and are disposed parallel to each other at equal intervals in the circumferential direction of the anvil roll  210 . 
     The first protruding portions  212   a  and the second protruding portions  212   b  are each symmetrically inclined at an angle smaller than 45 degrees with respect to the front-back direction, and are provided such that a clearance between two adjacent first protruding portions  212   a  is equal to a clearance between two adjacent second protruding portions  212   b , and intersections  212   c  of the first protruding portions  212   a  and the corresponding second protruding portions  212   b  are arranged at equal intervals on a line extending in the front-back direction and the circumferential direction of the anvil roll  210 . 
     As illustrated in  FIG. 12  that is an enlarged view of a part of  FIG. 11 ,  FIG. 13  that is a sectional view taken along line XIII-XIII of  FIG. 12 , and  FIG. 14  that is a sectional view taken along line XIV-XIV of  FIG. 12 , the first protruding portion  212   a  and the second protruding portion  212   b  are each provided with a groove  214  ( 214   a  or  214   b ) recessed inward in a radial direction of the anvil roll  210 . As illustrated in  FIG. 13  and the like, the first protruding portions  212   a  and the second protruding portions  212   b  are each provided with multiple grooves  214  at respective positions away from each other in the longitudinal directions C 1  and C 2  thereof. 
     Into these grooves  214 , a portion of the sheet  2   a  (sheet disposed on the anvil roll  210 ) with the elastic member  10  disposed is inserted. Thus, placement of the elastic members  10  for the bonding section  4  coincides with placement of the grooves for the protruding section  212 . 
     Specifically, in the present embodiment, as illustrated in  FIG. 12 , the first protruding portions  212   a  are each provided with the grooves (first grooves)  214   a  extending in the circumferential direction of the anvil roll  210 , being each formed in a portion between intersections  212   c  with the corresponding second protruding portions  212   b , more specifically, in a central portion of adjacent intersections  212   c . The second protruding portions  212   b  are each provided with the grooves (second grooves)  214   b  that are each formed in a portion between intersections  212   c  with the corresponding first protruding portions  212   a , more specifically, in a central portion of adjacent intersections  212   c . These grooves  214  are provided at equal intervals on a line extending along the circumferential direction of the anvil roll  210 , and are provided at equal intervals on a straight line extending along the front-back direction (i.e., a direction parallel to the rotation shaft of the anvil roll  210 , in other words, the same direction as the extending direction of the rotation shaft). 
     The sheet  2   a  is conveyed by the anvil roll  210  while having a portion where the elastic member  10  is disposed, the portion being inserted into the corresponding grooves  214 . As described above, in the present embodiment, the elastic members  10  are guided into the corresponding grooves  214  by a guide plate  112  provided with guide grooves  114   b  at positions corresponding to the respective grooves  214 , so that the elastic members  10  are each stably disposed at an appropriate position on the sheet  2   a.    
     In the present embodiment, the sheet  2   a  together with the elastic members  10  that are partially inserted into the corresponding grooves  214  are conveyed by the anvil roll  210 . Only the sheet  2   a  with portions inserted into the grooves may be conveyed. 
     The grooves  214  are formed in the protruding section  212  at portions where the respective elastic members  10  are disposed as described above, so that at least a part of each of the elastic members  10  disposed on a pre-bonding sheet is retracted in the corresponding grooves when the pre-bonding sheet is compressed during bonding. Thus, an elastic member  10  is prevented from being cut when being compressed. 
     However, when the groove  214  has an excessive sectional area, the elastic member  10  may be less likely to be appropriately bonded to the sheets  2   a ,  2   b . Thus, in the present embodiment, as illustrated in  FIG. 14 , when the elastic member  10  with a natural length is disposed in the groove  214 , a part of the elastic member  10  protrudes outward from the groove  214 , and the rest of the elastic member  10  is accommodated in the groove  214 . Specifically, the groove  214  is configured to have a section taken along a plane orthogonal to the circumferential direction (conveying direction) of the anvil roll  210 , the section having a shape in which when the elastic member  10  is disposed in the groove  214  with the natural length, a part of the elastic member  10  protrudes outward in the radial direction of the anvil roll  210  from a linear imaginary line L 10  connecting open ends (Q 1 , Q 2 ) of the groove  214 . The groove  214  is also configured to have the sectional shape in which when the elastic member  10  is extended from a natural state (e.g., when being elongated 300%) is disposed in the groove  214 , a part of the elastic member  10  protrudes outward in the radial direction of the anvil roll  210  from the linear imaginary line L 10  connecting the open ends (Q 1 , Q 2 ) of the groove  214 . The groove  214  described above preferably has a sectional shape of a substantially V-shape as illustrated in  FIG. 14 . The groove  214  described above preferably has a sectional area SI smaller than a sectional area of the elastic member  10  to be disposed. The sectional shape of the groove  214  is not limited to a V-shape, and may be another shape such as a U-shape. 
     As described above, when the groove  214  is formed with a sectional shape allowing the elastic member  10  to partially protrude, the elastic member  10  disposed in the groove and the sheets  2   a ,  2   b  can be appropriately compressed and bonded to each other during ultrasonic welding while the elastic member  10  is retracted into the groove  214 . Thus, the sheets  2   a ,  2   b  and the elastic members  10  can be more reliably bonded to each other while the elastic members  10  is prevented from being damaged. Specifically, a portion of the elastic member  10  inside the imaginary line L 10 , i.e., the portion accommodated in the groove  214 , can be retracted inside the groove  214  (a side away from the horn  220 ) while pressure is appropriately applied to a portion of the elastic member  10 , protruding outside the imaginary line L 10  connecting the open ends Q 1  and Q 2  of the groove  214 , and the sheets  2   a ,  2   b . This enables preventing the elastic member  10  from being damaged while securing bonding force between the elastic member  10  and the sheets  2   a ,  2   b.    
     In particular, when the sectional shape of the groove  214  is set such that the elastic member  10  partially protrudes outward in the radial direction of the anvil roll  210  from the linear imaginary line L 10  connecting the open ends (Q 1 . Q 2 ) of the groove  214  when the elastic member  10  elongated 300% is disposed in the groove  214 , the sheets  2   a ,  2   b  and the elastic member  10  can be more reliably bonded to each other by being appropriately subjected to pressure while the elastic member  10  is prevented from being damaged. 
     The horn  220  illustrated in  FIGS. 6 and 10A  is a device that applies ultrasonic vibration to a pre-bonding sheet conveyed by the anvil roll  210  while compressing (pressurizing while sandwiching) the pre-bonding sheet with the outer peripheral surface of the anvil roll  210 . The horn  220  is disposed to face the outer peripheral surface of the anvil roll  210 . In the example of  FIG. 6 , the horn  220  is disposed to face an upper portion of the outer peripheral surface of the anvil roll  210 . The horn  220  is provided at its leading end with an output unit  221  that applies ultrasonic vibration toward the outer peripheral surface of the anvil roll  210 . 
     The horn  220  applies ultrasonic vibration to a pre-bonding sheet with the output unit  221  pressing against the pre-bonding sheet and compressing the pre-bonding sheet together with the anvil roll  210 . This causes the sheets  2   a ,  2   b  to be melted and welded to each other. The elastic member  10  is also melted, so that the elastic member  10  and the sheets  2   a .  2   b  are welded to each other. Specifically, the output unit  221  compresses the pre-bonding sheet together with the protruding section  212 , and bonds the sheets  2   a ,  2   b  to each other and bonds the elastic member  10  to the sheets  2   a ,  2   b  in a portion of the pre-bonding sheet disposed on the protruding section  212 . The leading end of the output unit  221  has a planar shape (See  FIGS. 13 and 14 ). 
     As described above, in the present embodiment, the covering layer  10   b  is made of magnesium stearate having a lower melting point than the rubber thread  10   a . Thus, during welding between the elastic member  10  and the sheets  2   a ,  2   b , the covering layer  10   b  is melted to weld the covering layer  10   b  to the sheets  2   a ,  2   b  without melting of the rubber thread  10   a.    
     The output unit  221  at the leading end of the horn  220  extends in the front-back direction, and the horn  220  applies ultrasonic vibration to the outer peripheral surface of the anvil roll  210  throughout in a rotation axis direction of the anvil roll  210 . While a pre-bonding sheet is conveyed by the anvil roll  210 , the horn  220  always applies ultrasonic vibration. Thus, as the pre-bonding sheet is conveyed by the anvil roll  210 , the pre-bonding sheet is continuously bonded. 
     As illustrated in  FIG. 6 , in the present embodiment, the sheet  2   a  is guided by the first guide roller  102  to a position separated upstream from the horn  220  on the outer peripheral surface of the anvil roll  210 . The sheet  2   a  is conveyed toward the horn  220  along the outer peripheral surface of the anvil roll  210  along with rotation of the anvil roll  210 . 
     The sheet  2   b  is introduced into a portion of the outer peripheral surface of the anvil roll  210 , being near the horn  220  and upstream of the horn  220  in the conveying direction, by the nip roll  104 . 
     The elastic member  10  is introduced onto the outer peripheral surface of the anvil roll  210  at a position between a position where the sheet  2   a  is introduced onto the anvil roll  210  and a position where the sheet  2   b  is introduced onto the anvil roll  210  by the elastic member guide device  110 . As a result, the elastic member  10  is conveyed to a position facing the horn  220  while being sandwiched between the sheets  2   a ,  2   b.    
     Although the sheet  2   b  may be introduced onto the anvil roll  210  from the nip roll  104  at any position between a position where the elastic member  10  is introduced and a position facing the horn  220 , the position is preferably on a side close to the position facing the horn  220 , and more preferably near the position facing the horn  220 . In the present embodiment, as illustrated in  FIGS. 6 and 10A , the nip roll  104  is disposed at a position closest upstream of the horn  220  in the conveying direction of the sheets  2   a ,  2   b . i.e., the rotation direction of the anvil roll  210  (counterclockwise direction in  FIG. 10A ). This configuration enables preventing the elastic member  10  introduced onto the outer peripheral surface of the anvil roll  210  from being covered with the sheet  2   b  at an early stage and from causing positional deviation. 
     The elastic members  10  are introduced onto the outer peripheral surface of the anvil roll  210  while being arranged parallel to each other in the front-back direction, and are placed on the sheet  2   a , which is previously introduced onto the outer peripheral surface of the anvil roll  210 , parallel to each other in the width direction B, on the outer peripheral surface of the anvil roll  210 . The elastic members  10  are each introduced onto the anvil roll  210  while being elongated in the circumferential direction of the anvil roll  210 . In the present embodiment, the elastic members  10  are each introduced onto the anvil roll  210  while being elongated 300% of the natural state when the natural state is set to 100%. 
     Next, the elastic member guide device  110  (in particular, the guide plate  112 ) of the present embodiment will be described in detail. 
     As illustrated in  FIGS. 6 and 10 , the elastic member guide device  110  includes multiple guide rolls  111  and a guide plate  112  in a plate-like shape as a guide member. 
     Each of the guide rolls  111  is a rotary member rotatable about its axis extending in the front-back direction, and guides the elastic member  10  toward the anvil roll  210  while the elastic member  10  is elongated (e.g., elongated 300%). 
     As illustrated in  FIG. 6 to 10 , the guide plate  112  is a tabular member that guides the elastic members  10  to the corresponding grooves  214  (see  FIG. 11 to 14 ) formed on the outer peripheral surface of the anvil roll  210  while the elastic members  10  are separated from each other in the front-back direction, i.e., in a direction parallel to the axis of the anvil roll  210 . 
     The guide plate  112  has a leading end  114   a , which is an edge closest to the outer peripheral surface of the anvil roll  210 , and a proximal end disposed farther away from the anvil roll  210  than the leading end  114   a . The guide plate  112  is disposed to extend not only in a direction of coming into contact with and separating from the anvil roll  210  but also in the front-back direction. In the present embodiment, to prevent the guide plate  112  from interfering with the sheets  2   a ,  2   b , the guide plate  112  has a thickness t (dimension in a vertical direction illustrated in  FIG. 8 ) that is set to be small, and has a thin plate shape. 
     The leading end  114   a  of the guide plate  112  has a tapered shape. Specifically, as illustrated in  FIG. 8 , the guide plate  112  is provided in its leading end portion (portion close to the anvil roll  210 ) with an inclined surface  114   c  that is inclined toward the leading end  114   a  to approach a bottom surface  114   d  of the guide plate  112 . The inclined surface  114   e  and the bottom surface  114   d  form the leading end  114   a  tapered. In the present embodiment, the inclined surface  114   c  and the bottom surface  114   d  form an angle θ 2  that is set to about 10 degrees. 
     As illustrated in  FIGS. 10A and 10B , the leading end  114   a  of the guide plate  112  is disposed upstream (right side in  FIG. 10 ) of a contact point P 2  at which the guide plate  112  is in contact with the elastic member  10  on the outer peripheral surface of the anvil roll  210  in the rotation direction (counterclockwise direction in  FIG. 10 ) of the anvil roll  210  while facing upstream. The guide plate  112  is fixed in a stationary manner at a predetermined position facing the outer peripheral surface of the anvil roll  210 . In  FIGS. 10A and 10B , the guide plate  112  is fixed to a fixing member  113 , which is fixed to a panel or the like inside the apparatus, by screwing or the like to be prevented from being displaced. 
     The leading end  114   a  tapered of the guide plate  112  is provided with multiple guide grooves  114   b . Specifically, the guide grooves  114   b  are formed at respective positions away from each other at equal intervals in the front-back direction (direction parallel to the axis of the anvil roll  210 ) at the leading end  114   a  of the guide plate  112 , and individually hold the respective elastic members  10  to guide the elastic members  10  into the respective grooves  214  of the anvil roll  210 . As illustrated in  FIG. 9  that illustrates a part of the guide grooves  114   b  in  FIG. 7  in an enlarged manner, each of the guide grooves  114   b  is recessed from the leading end  114   a  of the inclined surface  114   c  toward the proximal end, and has a V-shape having an opening angle of 90 degrees. The guide grooves  114   b  each have a sectional shape that is not limited to the V-shape, and that may be another shape such as a U-shape. These guide grooves  114   b  reliably position and hold the respective elastic members  10  to guide the elastic members  10  onto the outer peripheral surface of the anvil roll  210  while separating the elastic members  10  from each other in the front-back direction. The guide grooves  114   b  face the respective grooves  214  formed in the anvil roll  210  and are provided at the same intervals as the grooves  214  to guide the elastic members  10  into the respective grooves  214 . 
     The leading end  114   a  of the guide plate  112  and the guide grooves  114   b  formed at the leading end  114   a  face in an opposite direction (i.e., a clockwise direction) to the rotation direction of the anvil roll  210  (the counterclockwise direction in  FIGS. 6 and 10A ). Thus, the elastic members  10  engaged into the respective guide grooves  114   b  are pulled by the anvil roll  210  rotating in the counterclockwise direction, and are bent at bottoms P 1  of the respective guide groove  114   b . Each of the elastic members  10  then extends in a tangential direction of the contact P 2  on the outer peripheral surface of the anvil roll  210 , and is inserted into the corresponding one of the grooves  214  (see  FIG. 11 to 14 ) at the contact P 2  on the outer peripheral surface of the anvil roll  210 . 
     As illustrated in  FIGS. 10A and 10B , it is conceivable that as a length L 1  (specifically, a distance L 1  from the bottom P 1  of a guide groove  114   b  to the contact point P 2  at which an elastic member  10  is in contact with the anvil roll  210 ) of the elastic member  10  positioned between the guide groove  114   b  and a groove  214  of the anvil roll  210  decreases in the guide plate  112 , the elastic member  10  tends to be less likely to be detached from the groove  214  of the anvil roll  210 . 
     As a result of experimentally examining a correlation between the length L 1  (i.e., a free distance L 1  with which the elastic member  10  moves in the air without being restrained) of the elastic member  10  positioned between the guide groove  114   b  and the groove  214  of the anvil roll  210  and probability of vibration of the elastic member  10 , the present inventors have found that there is a correlation as shown in Table 1 below. In the experiment, a linear rubber thread having a diameter of 0.1 mm or more was used as the elastic member  10 , and a frequency of touches of the rubber thread and the amount of vibration of the rubber thread were observed for a certain period of time by continuously inserting the rubber thread from the guide groove  114   b  of the guide plate  112  into the groove  214  of the anvil roll  210  in the manufacturing apparatus  100 . Results of the experiment are shown in Table 1 below. 
     
       
         
           
               
               
             
               
                   
                 TABLE 1 
               
             
            
               
                   
                   
               
               
                   
                 FREE DISTANCE L1 
               
            
           
           
               
               
               
               
            
               
                   
                 15 mm 
                 15~30 mm 
                 30~50 mm 
               
               
                   
                 OR LESS 
                 OR LESS 
                 OR LESS 
               
               
                   
                   
               
            
           
           
               
               
               
               
            
               
                 VIBRATION SUPPRESSION 
                 ⊚ 
                 Δ 
                 X 
               
               
                 EFFECT OF ELASTIC 
               
               
                 MEMBER (RUBBER THREAD) 
               
               
                 PROBABILITY OF 
                 0.08% 
                 4.66% 
                 10% 
               
               
                 VIBRATION OF RUBBER 
                   
                   
                 OR MORE 
               
               
                 THREAD WITH DIAMETER 
               
               
                 OF 0.1 mm OR MORE 
               
               
                   
               
            
           
         
       
     
     The experimental results in Table 1 show that when the free distance L 1  of the rubber thread is 15 mm or less, the rubber thread having a diameter of 0.1 mm or more has a probability of vibration of 0.08%, resulting in good (double circle) in vibration suppression effect of the rubber thread. 
     Even when having a free distance L 1  of 15 mm to 30 mm or less in the range larger than 15 mm, the rubber thread has a probability of vibration of 4.66% that falls within the allowable probability (5%), and thus it can be seen that the vibration suppression effect of the rubber thread is a pass or a pass mark (triangle). 
     When having a free distance L 1  within a range of more than 30 mm, e.g., 30 mm to 50 mm or less, the rubber thread has a probability of vibration of 10% or more that greatly exceeds the allowable probability (5%), and thus it can be seen that the vibration suppression effect of the rubber thread is unacceptable (cross). 
     To reduce a defect in which the elastic member  10  such as a rubber thread is detached from the groove  214  of the anvil roll  210  based on the above experimental results, the guide plate  112  of the present embodiment is preferably disposed such that the elastic member  10  positioned between the guide groove  114   b  and the groove  214  of the anvil roll  210  has a length L 1  of 30 mm or less, preferably of 15 mm or less, and practically within a range of 1 mm to 30 mm, preferably within a range of 1 mm to 15 mm. The distance L 1  is set to be larger than zero to prevent the guide plate  112  from coming into contact with the anvil roll  210  (specifically, the sheet  2   a  wound around the outer peripheral surface of the anvil roll  210 ), i.e., to allow the guide plate  112  to be separated by a thickness of the sheet  2   a  or more. 
     As illustrated in  FIG. 10B , the guide plate  112  is disposed such that a gap  81  between the bottom P 1  of the guide groove  114   b  and the outer peripheral surface of the protruding section  212  of the anvil roll  210  is 1 mm or less, preferably is 0.3 mm or less, and practically within a range of 0.1 mm to 1 mm, preferably within a range of 0.1 mm to 0.3 mm. 
     As illustrated in  FIG. 10B , the guide plate  112  is disposed such that the bottom surface  114   d  facing the anvil roll  210  forms an angle θ 1  of 30 degrees or less (practically, an angle within a range of 1 to 30 degrees) with respect to a tangent line of the anvil roll  210  at the contact point P 2  where the anvil roll  210  and the elastic member  10  are in contact with each other. 
     As illustrated in  FIGS. 6 and 10A , the multiple guide rolls  111  is disposed upstream of the guide plate  112  in the conveying direction of the elastic member  10 , and guides the elastic member  10  into the guide groove  114   b . Each of the guide rolls  111  is provided in its outer peripheral surface with grooves (not illustrated) away from each other in an extending direction of a rotation shaft of the guide roll  111  to guide the elastic members  10  into the respective guide grooves  114   b.    
     As illustrated in  FIG. 10A , a guide roll  111 A positioned most downstream of the multiple guide rolls  111  is disposed to have a distance L 2  of 50 mm or more in which the elastic member  10  is separated from the guide roll from the guide roll  111  and inserted into the guide groove  114   b  to prevent influence due to rotation unevenness and rattling of the guide roll  111 A (e.g., a slack of the elastic member  10  and the like). 
     As illustrated in  FIGS. 6 and 10A , the nip roll  104  is disposed upstream of the horn  220 . The nip roll  104  can sandwich two sheets and the elastic member  10  in cooperation with the anvil roll  210  in a region where the elastic member  10  is inserted into the groove  214  of the anvil roll  210 , i.e., a section from a first position (i.e., a contact point between the anvil roll  210  and the elastic member  10 ) P 2  (see  FIG. 10B ) where the elastic member  10  is inserted into the groove  214  in the outer peripheral surface of the anvil roll  210  to the output unit  221  (see  FIG. 10A ) of the horn  220 . 
     As illustrated in  FIG. 10A , in the present embodiment, a conveying distance L 3 , in which the elastic member is compressed by the horn  220  after coming into contact with the groove  214  of the anvil roll  210 , is set to 150 mm or less (practically, a range of 1 mm to 150 mm) to reduce a defect in which the elastic member  10  is detached from the groove  214  of the anvil roll  210  while the elastic member  10  is compressed by the horn  220  after coming into contact with the groove  214  of the anvil roll  210 . 
     The conveying distance L 3  described above has an optimum numerical value derived from experiments performed by the present inventors. Specifically, as shown in Table 2 below, when a linear rubber thread having a diameter of 0.1 mm or more was used as the elastic member  10 , a relationship between the conveying distance L 3 , in which the rubber thread is compressed by the horn  220  after coming into contact with the groove  214  of the anvil roll  210 , and the probability of vibration of the rubber thread, was examined through experiments. 
     
       
         
           
               
               
               
             
               
                 TABLE 2 
               
               
                   
               
               
                 CONVEYING 
                 FREE DISTANCE 
                 FREE DISTANCE 
               
               
                 DISTANCE L3 
                 L1 = 11 mm 
                 L1 = 19 mm 
               
               
                   
               
             
            
               
                  20 mm 
                 0.08% 
                 1.12% 
               
               
                 150 mm 
                 0.16% 
                 3.66% 
               
               
                 300 mm 
                 5.73% 
                 9.62% 
               
               
                   
               
            
           
         
       
     
     The experimental results in Table 2 show that when the conveying distance L 3  of the rubber thread is 150 mm, the probability of vibration of the rubber thread under conditions where the free distance L 1  is 11 mm is 0.16%, and the probability of vibration of the rubber thread under conditions where the free distance L 1  is 19 mm is 3.66%, which fall within an allowable probability (5%), and thus the vibration suppression effect of the rubber thread is sufficiently exhibited (passed). Table 2 also shows that when the conveying distance L 3  is 20 mm, the probability of vibration of the rubber thread under the conditions where the free distance L 1  is 11 mm decreases to 0.08%, and the probability of vibration of the rubber thread under the conditions where the free distance L 1  is 19 mm decreases to 1.12%. 
     In contrast, when the conveying distance L 3  of the rubber thread is 300 mm, the probability of vibration of the rubber thread under the conditions where the free distance L 1  is 11 mm is 5.73%, and the probability of vibration of the rubber thread under the conditions where the free distance L 1  is 19 mm is 9.62%, which greatly exceeds the allowable probability (5%), and thus the vibration suppression effect of the rubber thread is insufficient (failed). 
     The experimental results in Table 2 above show that the conveying distance L 3  is preferably set to 150 mm or less to reduce a defect in which the elastic member  10  is detached from the groove  214  of the anvil roll  210  while the elastic member  10  is compressed by the horn  220  after coming into contact with the groove  214  of the anvil roll  210 . 
     (3) Wearing Article and Method for Manufacturing the Same 
       FIG. 15  is a schematic view illustrating a disposable diaper (wearing article)  20  using the composite stretchable member  1  as a usage example of the composite stretchable member  1  configured as described above. 
     The disposable diaper  20  includes a waistline portion  21  having a front abdomen portion  21   a  disposed on the front of the abdomen of a wearer and a rear back portion  21   b  disposed on the buttocks of the wearer, and a crotch portion  22  disposed at the crotch of the wearer. The composite stretchable member  1  of the present embodiment is used for the front abdomen portion  21   a  and the rear back portion  21   b . For example, the composite stretchable member  1  is applied to the front abdomen portion  21   a  and the rear back portion  21   b  such that the extending direction of the composite stretchable member  1  aligns with a waistline direction (left-right direction in  FIG. 15 ) at the time of wearing. 
       FIG. 16  is a view illustrating an example of a method for manufacturing the disposable diaper  20 , and the present invention is not limited thereto. The manufacturing method illustrated in  FIG. 16  includes stages  1  to  3 . First, in the stage  1 , a pair of continuous bodies  101  in which composite stretchable members  1  are connected in the conveying direction is prepared. That is, a continuous body  101  for forming the front abdomen portion  21   a  and a continuous body  101  for forming the rear back portion  21   b  are prepared. Then, both the continuous bodies  101  are conveyed in the longitudinal direction of the continuous bodies  101  while being disposed parallel to each other, and the crotch portion  22  is placed on the continuous bodies  101  such that the longitudinal direction of the crotch portion is orthogonal to the longitudinal direction of the continuous bodies  101 . For example, crotch portions  22  are placed away from each other in the conveying direction. Then, the crotch portions  22  are bonded the continuous bodies  101  to form a bonded body  102  (step of forming a bonded body). 
     Next, in the stage  2 , a hole serving as a leg opening is formed between the crotch portions  22  adjacent to each other. After that, the bonded body  102  is folded in two along a center line CL 1  in the width direction (direction orthogonal to the longitudinal direction of the continuous bodies  101 ) as a fold such that the crotch portion  22  is positioned inside (step of folding in two). 
     Next, in the stage  3 , portions of the respective continuous bodies  101  positioned in the middle of the adjacent crotch portions  22 , which overlap each other, are bonded to each other along a direction orthogonal to the longitudinal direction of the continuous bodies  101  to form a side seal SS (step of sealing a side), and the continuous bodies  101  are cut along a cutting line K in the side seal portion (step of cutting). 
     In this manner, the disposable diaper  20  including the waistline portion  21  (the front abdomen portion  21   a  and the rear back portion  21   b ) that is formed of the composite stretchable member  1  to stretch and contract in the waistline direction is manufactured. 
     In the present embodiment, the step of opening the hole serving as the leg opening may or may not be performed before the crotch portions  22  are bonded to the continuous bodies  101 . Additionally, each elastic member  10  of the composite stretchable member  1  may be bonded to two sheets  2   a ,  2   b  with a hot melt adhesive near a portion corresponding to the cutting line K. In this way, coming off of each elastic member  10  due to cutting along the cutting line K can be prevented. 
     Features of the Present Embodiment 
     (1) 
     The manufacturing apparatus  100  for manufacturing a composite stretchable member of the present embodiment is configured such that as illustrated in  FIG. 6 to 10 , the elastic member guide device  110  includes the guide plate  112  in a plate-like shape as a guide member that guides elastic members  10  to the respective grooves  214  in the outer peripheral surface of the anvil roll  210 . The guide plate  112  includes the leading end  114   a  closest to the outer peripheral surface of the anvil roll  210 , and the guide grooves  114   b  provided at the leading end  114   a  and holding the respective elastic members  10  in a state away from each other in a direction parallel to the axis of the anvil roll  210  to guide the elastic members  10  to the respective grooves  214  in the outer peripheral surface of the anvil roll  210  in the state away from each other in the direction parallel to the axis of the anvil roll  210 . The guide plate  112  is disposed to allow the elastic member  10  positioned between the guide groove  114   b  and the groove  214  of the anvil roll  210  to have a length L 1  (free distance L) of 30 mm or less. 
     As described above, disposing the guide plate  112  to allow the elastic member  10  positioned between the guide groove  114   b  and the groove  214  of the anvil roll  210  to have the length L 1  of 30 mm or less enables reducing a defect in which the elastic member  10  is detached from the groove  214  of the anvil roll  210  when the elastic member  10  is fed from the guide groove  114   b  to the groove  214  of the anvil roll  210 . As a result, a function of preventing cutting of the elastic member  10  can be improved. 
     (2) 
     The guide plate  112  is preferably disposed to allow the elastic member  10  positioned between the guide groove  114   b  and the groove  214  of the anvil roll  210  to have a length L 1  of 15 mm or less. This case enables further reducing the defect in which the elastic member  10  is detached from the groove  214  of the anvil roll  210  when the elastic member  10  is fed from the guide groove  114   b  to the groove  214  of the anvil roll  210 . As a result, the function of preventing cutting of the elastic member  10  can be further improved. 
     (3) 
     The manufacturing apparatus  100  for manufacturing a composite stretchable member according to the present embodiment is configured such that the guide plate  112  is disposed to allow the gap  81  between the bottom P 1  of the guide groove  114   b  and the outer peripheral surface of the protruding section  212  of the anvil roll  210  to be 1 mm or less, preferably 0.3 mm or less. This configuration enables the guide groove  114   b  to approach the outer peripheral surface of the protruding section of the anvil roll  210 , so that the distance L 1 , in which the elastic member  10  leaves the guide groove  114   b  and is inserted into the groove  214  of the anvil roll  210 , can be shortened. This enables further reducing the defect in which the elastic member  10  is detached from the groove  214  of the anvil roll  210 . As a result, the function of preventing cutting of the elastic member  10  can be further improved. 
     (4) 
     The manufacturing apparatus  100  for manufacturing a composite stretchable member of the present embodiment includes a guide member that guides the elastic members  10  onto the outer peripheral surface of the anvil roll  210  in a state where the elastic members  10  are away from each other in a direction parallel to the axis of the anvil roll  210 , and that is formed of the guide plate  112  in a plate-like shape. The leading end  114   a  of the guide plate  112  is an edge of the guide plate  112  closest to the outer peripheral surface of the anvil roll  210  and has a tapered shape. The multiple guide grooves  114   b  is formed at the leading end  114   a  tapered. This configuration enables the guide plate  112  to be disposed close to the outer peripheral surface of the anvil roll  210  without interfering with the anvil roll  210  and the sheets  2   a ,  2   b  wound around the outer peripheral surface of the anvil roll  210 , by using the guide plate  112  in a plate-like shape with the leading end  114   a  tapered. This enables further reducing the defect in which the elastic member  10  is detached from the groove  214  of the anvil roll  210 , by shortening the distance L 1  between the guide groove  114   b  and the groove  214  of the anvil roll  210 . The guide groove  114   b  is formed at the leading end  114   a  tapered, so that frictional resistance between the elastic member  10  and the guide plate  112  when the elastic member  10  posses through the guide groove  114   b  can be reduced. As a result, the function of preventing cutting of the elastic member  10  can be further improved. 
     (5) 
     The manufacturing apparatus  100  for manufacturing a composite stretchable member of the present embodiment is configured such that the leading end  114   a  of the guide plate  112  is disposed upstream (right side in  FIG. 10 ) of the contact point P 2  at which the guide plate  112  is in contact with the elastic member  10  on the outer peripheral surface of the anvil roll  210  in the rotation direction (counterclockwise direction in  FIG. 10 ) of the anvil roll  210  while facing upstream. The guide plate  112  is disposed such that the bottom surface  114   d  facing the anvil roll  210  forms an angle θ 1  of 30 degrees or less with respect to the tangent line of the anvil roll  210  at the contact point P 2  where the anvil roll  210  and the elastic member  10  are in contact with each other. 
     This configuration enables the bottom of the guide groove  114   b  to approach the outer peripheral surface of the anvil roll  210 , so that the distance L 1 , in which the elastic member  10  leaves the guide groove  114   b  and is inserted into the groove  214  of the anvil roll  210 , can be shortened. This enables further reducing the defect in which the elastic member  10  is detached from the groove  214  of the anvil roll  210 . As a result, the function of preventing cutting of the elastic member  10  can be further improved. 
     (6) 
     The manufacturing apparatus  100  for manufacturing a composite stretchable member of the present embodiment further includes the nip roll  104  that is disposed on upstream of the horn  220  in the conveying direction of the sheets  2   a ,  2   b  (the rotation direction of the anvil roll  210 ) and sandwiches two sheets and the elastic member  10  in cooperation with the anvil roll  210  in the region where the elastic member  10  is inserted into the groove  214  of the anvil roll  210 , i.e., the section from the contact point P 2  (see  FIG. 10B ) that is the first position where the elastic member  10  is inserted into the groove  214  in the outer peripheral surface of the anvil roll  210  to the output unit  221  (see  FIG. 10A ) of the horn  220 . 
     This configuration enables further reducing a defect in which the elastic member  10  inserted into the groove  214  of the anvil roll  210  is detached from the groove  214  of the anvil roll  210  before reaching the horn  220 . As a result, the function of preventing cutting of the elastic member  10  can be further improved. Additionally, even when the elastic member  10  contracts and tries to return when the elastic member  10  is cut downstream of the nip roll  104 , return of the elastic member  10  is prevented because an end portion of the elastic member  10  is sandwiched between the nip roll  104  and the anvil roll  210 . This facilitates restoration work of the manufacturing apparatus  100 . 
     (7) 
     The manufacturing apparatus  100  for manufacturing a composite stretchable member of the present embodiment is configured such that the elastic member guide device  110  further includes the guide roll  111  that is disposed upstream of the guide plate  112  in the conveying direction of the elastic member  10  to guide the elastic member  10  into the guide groove  114   b . This configuration enables the elastic member  10  to be reliably guided into the guide groove  114   b , so that the defect in which the elastic member  10  is detached from the guide groove  114   b  can be prevented. 
     (8) 
     The manufacturing apparatus  100  for manufacturing a composite stretchable member according to the present embodiment is configured such that the guide roll  111  (specifically, the guide roll  111 A positioned most downstream of the multiple guide rolls  111 ) is disposed to allow the distance L 2  in which the elastic member  10  is separated from the guide roll  11   l  and inserted into the guide groove  114   b  to be 50 mm or more. This configuration enables eliminating influence on the elastic member  10  due to rotation unevenness and rattling of the guide roll  111 , such as a slack of the elastic member  10 . 
     (9) 
     The manufacturing apparatus  100  for manufacturing a composite stretchable member of the present embodiment is configured such that the conveying distance L 3 , in which the elastic member  10  is compressed by the horn  220  after coming into contact with the groove  214  of the anvil roll  210 , is 150 mm or less. This configuration allows the vibration suppression effect of the elastic member  10  to be sufficiently exerted as shown in Table 2 above, and thus enables reducing the defect in which the elastic member  10  is detached from the groove  214  of the anvil roll  210  during a period from when the elastic member  10  comes into contact with the groove  214  of the anvil roll  210  to when the elastic member  10  is compressed by the horn  220 . As a result, the function of preventing cutting of the elastic member  10  can be further improved. 
     (Modification) 
     (A) 
     Although in the present embodiment, the guide plate  112  in a plate-like shape has been described as an example of the guide member that guides the elastic members  10  onto the outer peripheral surface of the anvil roll  210  while the elastic members  10  are separated from each other in the direction parallel to the axis of the anvil roll  210 , the present invention is not limited thereto. 
     As a modification of the present invention, instead of the guide plate  112  in a plate-like shape, a guide roller or the like having multiple guide grooves in its outer peripheral surface may be used as another guide member. Even the guide roller enables the elastic members  10  to be guided into the respective grooves  214  in the outer peripheral surface of the anvil roll  210  while the elastic members  10  are separated from each other in the direction parallel to the axis of the anvil roll  210 . 
     Even this configuration enables reducing the defect in which the elastic member  10  is detached from the groove  214  of the anvil roll  210  when the elastic member  10  is fed from the guide groove to the groove  214  of the anvil roll  210  by disposing the guide roller to allow the distance L 1 , in which the elastic member  10  is separated from the guide groove  114   b  and inserted into the groove  214  of the anvil roll  210 , to be 30 mm or less. As a result, the function of preventing cutting of the elastic member  10  can be improved. 
     (B) 
     Although in the above embodiment, there is described the bonding device that performs ultrasonic welding and generates frictional heat by applying ultrasonic vibration to the sheets  2   a ,  2   b  to heat the sheets  2   a ,  2   b , a specific configuration of heating and welding the sheets  2   a ,  2   b  is not limited thereto. As another modification of the present invention, for example, a device that heats and welds the sheets  2   a ,  2   b  without vibrating them may be used as a bonding device to heat and weld the sheets  2   a ,  2   b  in the step of bonding without vibrating them, as in so-called heat sealing. 
     (C) 
     Although in the above embodiment, the guide plate  112  is fixed to a fixing member  113 , which is fixed to a panel or the like inside the apparatus, by screwing or the like to be prevented from being displaced as illustrated in  FIGS. 10A and 10B , the present invention is not limited thereto. 
     As still another modification of the present invention, the guide plate  112  may be configured to be movable between a position close to the anvil roll  210  (conveying roller) illustrated in  FIG. 17  and a position away from the anvil roll  210  illustrated in  FIG. 18 . 
     Specifically, the elastic member guide device  110  illustrated in  FIG. 17 to 18  includes not only the multiple guide rolls  111  and the guide plate  112 , but also a holding member  115  that holds both of the guide rolls  111  and the guide plate  112 , a support shaft  116  that supports the holding member  115  to be swingable vertically, and a supply roll  117  disposed on upstream of the guide rolls  111  in the conveying direction of the elastic member  10 . The support shaft  116  and a rotation shaft of the supply roll  117  are fixed at a predetermined position inside the manufacturing apparatus  100  to be prevented from being displaced. The multiple guide rolls  111  and the supply roll  117  are each provided in its outer peripheral surface with a groove for guiding the elastic member  10 . 
     As illustrated in  FIGS. 17 to 18 , when the holding member  115  holding the guide rolls  11 I and the guide plate  112  swings vertically on the support shaft  116  as a rotation center, the guide plate  112  can move between a position close to the anvil roll  210  (conveying roller) illustrated in  FIG. 17  and a position away from the anvil roll  210  illustrated in  FIG. 18 . 
     As illustrated in  FIG. 17 , when the guide plate  112  is at the position close to the anvil roll  210  (i.e., the position during operation of the manufacturing apparatus  100 ), the elastic member  10  is pressed by the guide plate  112  from above and moved from the supply roll  117  to the multiple guide rolls  111 , and the guide plate  112  in this order to be fed onto the outer peripheral surface of the anvil roll  210 . 
     In contrast, as illustrated in  FIG. 18 , when the guide plate  112  is at the position away from the anvil roll  210  (the position allowing the elastic member  10  such as a rubber thread to pass), the guide plate  112  is retracted upward from the elastic member  10 . This enables facilitating work of setting the elastic member  10  in the guide device  110 , specifically, work of stretching the elastic member  10  between the groove of the guide roll  111 A positioned most downstream of the multiple guide rolls  111  and the outer periphery of the anvil roll  210 . When the guide plate  112  is returned to the position close to the anvil roll  210  illustrated in  FIG. 17  again after the elastic member  10  is set in the guide device  110 , the elastic member  10  is inserted into the groove  114   b  (see  FIG. 10B ) of the guide plate  112  and is placed in the groove of each of the guide rolls  111 . This enables the guide device  110  to return to the state illustrated in  FIG. 17 . 
     Summary of Embodiment 
     The above embodiment is summarized as follows. 
     The manufacturing apparatus for manufacturing a composite stretchable member according to the above embodiment is a manufacturing apparatus for manufacturing a composite stretchable member including the two sheets and the multiple elastic members sandwiched between the two sheets by bonding the two sheets to each other and bonding the sheets to the multiple elastic members while conveying each of the sheets in a longitudinal direction thereof, the manufacturing apparatus comprising: a bonding device that welds and bonds the multiple elastic members to the two sheets, and the two sheets to each other, while the multiple elastic members are sandwiched between the two sheets being conveyed; and a guide device that guides the two sheets and the multiple elastic members to the bonding device in such a manner that each of the multiple elastic members extends in a longitudinal direction thereof and is sandwiched between the two sheets, wherein: the bonding device includes: a conveying roller that has an outer peripheral surface used for conveying the two sheets sandwiching the multiple elastic members in the longitudinal direction of each of the two sheets and that rotates about an axis predetermined; and a compressing device that faces the outer peripheral surface of the conveying roller to compress the two sheets sandwiching the multiple elastic members between the outer peripheral surface of the conveying roller and the compressing device; the bonding device is configured to apply heat to the two sheets between the conveying roller and the compressing device; the outer peripheral surface of the conveying roller is provided with at least one protruding section formed protruding radially outward from the outer peripheral surface; the at least one protruding section includes multiple grooves extending in a conveying direction of the conveying roller and being away from each other in a direction parallel to the axis; the guide device includes a guide member provided with a leading end closest to the outer peripheral surface of the conveying roller, and the multiple guide grooves, provided in the leading end, for holding the corresponding multiple elastic members, in a state where the multiple elastic members are away from each other in a direction parallel to the axis of the conveying roller, to guide the multiple elastic members into the corresponding multiple grooves of the conveying roller, and the guide member is disposed to allow each of the multiple elastic members positioned between the guide grooves and the corresponding grooves of the conveying roller to have a length of 30 mm or less. 
     As a result of intensive studies on a technique in which the elastic member is reliably guided by the guide member without being detached from the groove in the outer peripheral surface of the conveying roller, the present inventors have found that when a distance in which the elastic member moves in the air between the guide groove of the guide member and the groove of the conveying roller, i.e., a free distance of the elastic member, is reduced to a predetermined distance or less, the elastic member can be reliably guided to the groove of the conveying roller and can be prevented from being detached from the groove, and thus having fabricated the manufacturing apparatus. 
     That is, the manufacturing apparatus described above is configured such that disposing the guide member to allow the elastic member positioned between the guide groove and the groove of the conveying roller to have a length of 30 mm or less enables reducing the defect in which the elastic member is detached from the groove of the conveying roller when the elastic member is fed from the guide groove to the groove of the conveying roller. As a result, the function of preventing cutting of the elastic member  10  can be improved. 
     The manufacturing apparatus for manufacturing a composite stretchable member described above is preferably configured such that the guide member is disposed to allow the elastic members positioned between the guide grooves and the corresponding grooves of the conveying roller to each have a length of 15 mm or less. 
     The configuration described above enables reducing the defect in which the elastic member is detached from the groove of the conveying roller when the elastic member is fed from the guide groove to the groove of the conveying roller by disposing the guide member to allow the elastic member positioned between the guide groove and the groove of the conveying roller to have a length of 15 mm or less. As a result, the function of preventing cutting of the elastic member  10  can be further improved. 
     The manufacturing apparatus for manufacturing a composite stretchable member described above is preferably configured such that the guide member is disposed to allow a shortest distance between a bottom of each of the guide grooves and an outer peripheral surface of the protruding section of the conveying roller to be 1 mm or less. 
     The configuration described above enables the guide groove to approach the outer peripheral surface of the protruding section of the conveying roller, and thus enables shortening a distance in which the elastic member leaves the guide groove and is inserted into the groove of the conveying roller. This enables further reducing the defect in which the elastic member is detached from the groove of the conveying roller. As a result, the function of preventing cutting of the elastic member can be further improved. 
     The manufacturing apparatus for manufacturing a composite stretchable member described above is preferably configured such that the guide member is formed in a plate-like shape, the leading end is an edge of the guide member in a plate-like shape, the edge being closest to the outer peripheral surface of the conveying roller and having a tapered shape, and the multiple guide grooves are formed at the leading end tapered. 
     The configuration described above enables the guide member to be disposed close to the outer peripheral surface of the conveying roller without interfering with the conveying roller and the sheet wound around the outer peripheral surface of the conveying roller, by using the guide member in a plate-like shape with the leading end tapered. This enables further reducing the defect in which the elastic member is detached from the groove of the conveying roller, by shortening the distance between the guide groove and the groove of the anvil roll. The guide groove is formed at the leading end tapered, so that frictional resistance between the elastic member and the guide member when the elastic member passes through the guide groove can be reduced. As a result, the function of preventing cutting of the elastic member can be further improved. 
     The manufacturing apparatus for manufacturing a composite stretchable member described above is preferably configured such that the leading end of the guide member is disposed upstream of a contact point at which the elastic members are in contact with the outer peripheral surface of the conveying roller in a rotation direction of the conveying roller, the leading end of the guide member facing upstream, and the guide plate is disposed to allow a surface of the guide plate facing the conveying roller to form an angle of 30 degrees or less with respect to a tangent line of the conveying roller at the contact point. 
     The configuration described above enables the bottom of the guide groove to approach the outer peripheral surface of the conveying roller, and thus enables shortening a distance in which the elastic member leaves the guide groove and is inserted into the groove of the conveying roller. This enables further reducing the defect in which the elastic member is detached from the groove of the conveying roller. As a result, the function of preventing cutting of the elastic member can be further improved. 
     The manufacturing apparatus for manufacturing a composite stretchable member described above preferably further includes a nip roll that is disposed upstream of the compressing device in the conveying direction of the sheet to sandwich the two sheets and the elastic members in cooperation with the conveying roller in a region where the elastic members are inserted into the corresponding grooves of the conveying roller. 
     The configuration described above enables further reducing a defect in which the elastic member inserted into the groove of the conveying roller is detached from the groove of the conveying roller before reaching the compressing device. As a result, the function of preventing cutting of the elastic member can be further improved. Additionally, even when the elastic member contracts and tries to return when the elastic member is cut downstream of the nip roll, return of the elastic member is prevented because an end portion of the elastic member is sandwiched between the nip roll and the conveying roller. This facilitates restoration work of the manufacturing apparatus. 
     The manufacturing apparatus for manufacturing a composite stretchable member described above preferably further includes a guide roll that is disposed upstream of the guide member in the conveying direction of the elastic members to guide the elastic members into the corresponding guide grooves. 
     The configuration described above enables the elastic member to be reliably guided to the guide groove, so that the defect in which the elastic member is detached from the guide groove can be prevented. 
     The manufacturing apparatus for manufacturing a composite stretchable member described above is preferably configured such that the guide roll is disposed to allow a distance in which the elastic members are separated from the guide roll and inserted into the corresponding guide grooves to be 50 mm or more. 
     The configuration described above enables eliminating influence on the elastic member due to rotation unevenness and rattling of the guide roll, such as a slack of the elastic member. 
     The manufacturing apparatus for manufacturing a composite stretchable member described above is preferably configured such that a conveying distance from a position where the guide member comes into contact with the corresponding grooves of the conveying roller to a position where the guide member is compressed by the compressing device is 150 mm or less. 
     The configuration described above enables reducing a defect in which the elastic member is detached from the groove of the conveying roller while the elastic member is compressed by the compressing device after coming into contact with the groove of the conveying roller. As a result, the function of preventing cutting of the elastic member can be further improved. 
     The manufacturing apparatus for manufacturing a composite stretchable member described above is preferably configured such that the guide member is movable between a position close to the conveying roller and a position away from the conveying roller. 
     The configuration described above enables facilitating work of setting the elastic member in the guide device by moving the guide member to the position away from the conveying roller. 
     As described above, the manufacturing apparatus for manufacturing a composite stretchable member of the present embodiment enables improving the function of preventing cutting by reducing the defect in which the elastic member is detached from the groove of the conveying roller.