Patent Publication Number: US-2020282608-A1

Title: Composite sheet manufacturing device and manufacturing method

Description:
TECHNICAL FIELD 
     The present invention relates to a composite sheet manufacturing device and manufacturing method, more particularly, to a device and method for manufacturing composite sheets having concave and convex shapes on the surfaces. 
     BACKGROUND ART 
     Composite sheets having concave and convex shapes on the surfaces thereof have been used for the skin-abutting faces of absorbent articles, such as disposable diapers and sanitary napkins. These kinds of composite sheets are manufactured by using such a device as shown in  FIG. 7 . 
     As shown in  FIG. 7 , in this device, a first sheet  84  is passed through the space between a first roller  81  having a circumferential face shaped into concave and convex shapes and a second roller  82  having a circumferential face shaped into convex and concave shapes to be engaged with the concave and convex shapes of the first roller  81 , whereby the first sheet  84  is shaped into concave and convex shapes. A second sheet  85  is superimposed onto the first sheet  84  having been shaped into the concave and convex shapes, and the first sheets  84  and  85  are bonded by thermal fusion when they are passed through the space between the first roller  81  and a third roller  83 , whereby a composite sheet  86  is completed (for example, refer to Patent Document 1). 
     Furthermore, for example, as shown in a sectional view in  FIG. 8  and an image view in  FIG. 9 , a composite sheet  150  has been proposed in which both of a first sheet  152  and a second sheet  154  are shaped. As shown in  FIGS. 8 and 9 , the first sheet  152  has raised portions  153  shaped by shaping and boundary portions  153   k  adjacent to the raised portions  153 . The second sheet  154  has projection portions  155  shaped by shaping and flat portions adjacent to the projection portions  155 . The projection portions  155  protrude to the same side as the raised portions  153  of the first sheet  152  in the inside of the raised portions  153  of the first sheet  152 . As shown in  FIG. 9 , in the boundary portions  153   k  of the first sheet  152 , multiple bonded sections  158  in which the first sheet  152  and the second sheet  154  are bonded by thermal fusion, ultrasonic welding or adhesion using an adhesive are shaped at intervals, that is, intermittently. 
     The composite sheet  150  described above is manufactured using a device  110  shown in a schematic view in  FIG. 10 . As shown in  FIG. 10 , around a first roller  112  having multiple recessed areas, not shown, a second roller  130  having multiple first projections  132  to be inserted into and extracted from the recessed areas of the first roller  112  with a clearance therebetween, a third roller  116 , a fourth roller  140 , a fourth roller  140  having multiple second projections  142  to be inserted into and extracted from the recessed areas of the first roller  112  with a clearance therebetween and a fifth roller  118  are disposed in this device  110 . 
     When being passed through the space between the first roller  112  and the second roller  130 , the first sheet  152  is shaped, and the second sheet  154  is superimposed thereon. When being passed through the space between the first roller  112  and the third roller  116 , both the superimposed sheets  152  and  154  are bonded to each other. Next, when being passed through the space between the first roller  112  and the fourth roller  140 , the second sheet  154  is shaped. And then, both the superimposed sheets  152  and  154  are passed through the space between the first roller and the fifth roller  118 , whereby the mutual bonding of both the sheets  152  and  154  is strengthened (for example, refer to Patent Document 2). 
     PRIOR ART DOCUMENT 
     Patent Document 
     
         
         Patent Document 1: JP-A-2005-111908 
         Patent Document 2: WO 2016/199543 
       
    
     SUMMARY OF INVENTION 
     Problem to be Solved by the Invention 
     When a composite sheet is manufactured, in the case that the rotation frequency of the first roller is made higher, the composite sheet can be manufactured at higher speed. 
     However, in the composite sheet manufacturing device in which the rollers  116 ,  118 ,  130  and  140  having outer diameters smaller than the outer diameter of the first roller  112  are disposed around the first roller  112  as shown in  FIG. 10 , it is not easy to make the rotation frequency of the first roller  112  higher; furthermore, if the rotation frequency of the first roller  112  is made higher, an unknown and new problem has been found in which the quality of the composite sheet becomes unstable. 
     In consideration of these circumstances, an object of the present invention is to provide a composite sheet manufacturing device and manufacturing method capable of manufacturing composite sheets easily at higher speed and capable of manufacturing composite sheets having stable quality even when the composite sheets are manufactured at higher speed. 
     Means for Solving the Problem 
     In order to solve the above-mentioned problem, the present invention provides a composite sheet manufacturing device configured as described below. 
     The composite sheet manufacturing device is equipped with (a) a first roller having a first outer circumferential face and a plurality of recessed areas retracted from the first outer circumferential face, (b) a second roller disposed so as to be adjacent to the first roller, rotated in synchronization with the first roller and having a second outer circumferential face opposed to the first outer circumferential face of the first roller and a plurality of first projections that protrude from the second outer circumferential face so as to be inserted into and extracted from the recessed areas of the first roller in a state in which a clearance is provided between each first projection thereof and each recessed area of the first roller, and (c) a third roller disposed so as to be adjacent to the first roller, rotated in synchronization with the first roller and having a third outer circumferential face opposed to the first outer circumferential face of the first roller. (i) A first sheet is fed in between the first roller and the second roller, conveyed while being supported by the first outer circumferential face of the first roller, and passed through a space between the first roller and the second roller, (ii) when the first sheet is passed through the space between the first roller and the second roller, the first projections of the second roller push the first sheet into the recessed areas of the first roller, and thereby the first sheet is shaped, (iii) a second sheet is superimposed onto the shaped first sheet and conveyed together with the first sheet and then passed through a space between the first roller and the third roller, and (iv) when the first sheet and the second sheet are passed through the space between the first roller and the third roller, the first roller and the third roller hold the first sheet and the second sheet therebetween, and thereby the first sheet and the second sheet are bonded to each other. (A) Each outer diameter of the first roller and the third roller is the same size, and (B) the third roller is joined to the first roller with a first gear pair therebetween so as to rotate at the same rotation frequency as that of the first roller. 
     With the above-mentioned configuration, since the first and third rollers are rotated at the same rotation frequency, the rotation frequency of the first roller is made higher easily in comparison with the configuration in which the rotation frequency of the third roller is higher than the rotation frequency of the first roller. As the rotation frequency of the first roller is made higher, the composite sheet can be manufactured at higher speed. 
     Hence, the composite sheet is manufactured easily at higher speed. 
     Furthermore, since the first roller and the third roller are joined mutually via the gears, the relative rotation error between the first roller and the third roller is unchanged even when the rotation frequency is changed. Hence, the quality of the composite sheet can be maintained even when the rotation frequency of the first roller is made higher. 
     Moreover, since the first roller and the third roller that hold the first and second sheets therebetween so as to bond the sheets are equal in outer diameter, rotate at the same rotation frequency and are always opposed mutually at the same portions, the rollers fit easily. Hence, the satisfactory bonding state between the first sheet and the second sheet can be maintained. 
     Still further, since the outer diameters of the first and third rollers are the same size and since the first roller is opposed mutually to the third roller at the same portion at all times, readjustment at the time of component exchange is made easy, and assembling accuracy is maintained easily. As a result, the quality of the manufactured composite sheet can be maintained constant. 
     Hence, even when the composite sheet is manufactured at higher speed, it is possible to manufacture the composite sheet having stable quality. 
     Preferably, an outer diameter of the second roller is equal to the outer diameters of the first roller and the second roller. The second roller is joined to the first roller with a second gear pair therebetween so as to rotate at the same rotation frequency as that of the first roller. 
     In this case, since the first roller and the second roller are joined mutually via the second gear pair, the relative rotation error between the first roller and the second roller is unchanged even when the rotation frequency is changed. Moreover, each of the recessed areas of the first roller corresponds one-to-one to each of the first projections of the second roller, while the first projections are inserted into and extracted from the recessed areas. Hence, the satisfactorily shaped state of the first sheet can be maintained. 
     Still further, since the outer diameters of the first and the second roller are the same size and since the first roller is opposed mutually to the second roller at the same portion at all times, readjustment at the time of component exchange is made easy, and assembling accuracy is maintained easily. As a result, the quality of the manufactured composite sheet can be maintained constant. 
     Hence, the composite sheet having more stable quality can be manufactured. 
     In a preferred embodiment, the composite sheet manufacturing device is further equipped with (d) a fourth roller disposed so as to be adjacent to the first roller, rotated in synchronization with the first roller and having a fourth outer circumferential face opposed to the first outer circumferential face of the first roller and a plurality of second projections that protrude from the fourth outer circumferential face so as to be inserted into and extracted from the recessed areas of the first roller in a state in which a clearance is provided between each second projection thereof and each recessed area of the first roller and (e) a fifth roller disposed so as to be adjacent to the first roller, rotated in synchronization with the first roller and having a fifth outer circumferential face opposed to the first outer circumferential face. (v) The first sheet and the second sheet having been passed through the space between the first roller and the third roller and bonded to each other are conveyed while being supported by the first outer circumferential face of the first roller and are passed through a space between the first roller and the fourth roller and then passed through a space between the first roller and the fifth roller, (vi) when the first sheet and the second sheet are passed through the space between the first roller and the fourth roller, the second projections of the fourth roller push the second sheet into the recessed areas of the first roller, and thereby the second sheet is shaped, (vii) when the first sheet and the second sheet are passed through the space between the first roller and the fifth roller, the first roller and the fifth roller hold the first sheet and the second sheet therebetween, and thereby the mutual bonding of the first sheet and the second sheet is strengthened. (C) An outer diameter of the fifth roller is equal to each outer diameter of the first roller and the third roller, and (D) the fifth roller is joined to the first roller with a third gear pair therebetween so as to rotate at the same rotation frequency as that of the first roller. 
     In this case, a composite sheet in which both of the first sheet and the second sheet thereof are formed is manufactured easily at higher speed. Furthermore, even when the composite sheet is manufactured at higher speed, it is possible to manufacture the composite sheet having stable quality. 
     Preferably, an outer diameter of the fourth roller is equal to each outer diameters of the first roller and the third roller. The fourth roller is joined to the first roller with a fourth gear pair therebetween so as to rotate at the same rotation frequency as that of the first roller. 
     In this case, since the first roller and the fourth roller are joined mutually via the fourth gear pair, the relative rotation error between the first roller and the fourth roller is unchanged even when the rotation frequency is changed. Moreover, each of the recessed areas of the first roller corresponds one-to-one to each of the second projections of the fourth roller, while the second projections are inserted into and extracted from the recessed areas. Hence, the satisfactorily shaped state of the second sheet can be maintained. 
     Still further, since the outer diameters of the first and the fourth roller are the same size and since the first roller is opposed mutually to the fourth roller at the same portion at all times, readjustment at the time of component exchange is made easy, and assembling accuracy is maintained easily. As a result, the quality of the manufactured composite sheet can be maintained constant. 
     Hence, the composite sheet having further more stable quality can be manufactured. 
     Moreover, in order to solve the above-mentioned problem, the present invention provides a composite sheet manufacturing method configured as described below. 
     A composite sheet manufacturing method has (i) a first step of disposing a second roller having first projections and a third roller so as to be adjacent to a first roller having a plurality of recessed areas retracted from an outer circumferential face of the first roller, rotating the first roller, the second roller and the third roller in synchronization with one another, and making the first projections of the second roller to be inserted into or extracted from the recessed areas of the first roller in a state in which a clearance is provided between each first projection of the second roller and each recessed area of the first roller, (ii) a second step of feeding a first sheet in between the first roller and the second roller being rotated, conveying the first sheet while supporting the first sheet on the outer circumferential face of the first roller, making the first sheet to be passed through a space between the first roller and the second roller, and making the first sheet to be pushed into the recessed areas of the first roller by the first projections of the second roller when the first sheet is passed through the space between the first roller and the second roller, thereby shaping the first sheet, (iii) a third step of superimposing a second sheet onto the shaped first sheet, conveying the second sheet together with the first sheet, and making the first sheet and the second sheet to be passed through a space between the first roller and the third roller, and holding the first sheet and the second sheet between the first roller and the third roller when the first sheet and the second sheet are passed through the space between the first roller and the third roller, thereby bonding the first sheet and the second sheet to each other. At the first step, (A) each outer diameter of the first roller and the third roller is made the same size, and (B) the third roller is joined to the first roller with a first gear pair therebetween, and the third roller is made to rotate at the same rotation frequency as that of the first roller. 
     With the above-mentioned method, since the first and third rollers are rotated at the same rotation frequency, the rotation frequency of the first roller can be made higher easily in comparison with the case in which the rotation frequency of the third roller is higher than the rotation frequency of the first roller. As the rotation frequency of the first roller is made higher, the composite sheet can be manufactured at higher speed. 
     Hence, the composite sheet can be manufactured easily at higher speed. 
     Furthermore, according to the above-mentioned method, since the first roller and the third roller are joined mutually via the gears, the relative rotation error between the first roller and the third roller is unchanged even when the rotation frequency is changed. Hence, the quality of the composite sheet can be maintained even when the rotation frequency of the first roller is made higher. 
     Moreover, since the first roller and the third roller that hold the first and second sheets therebetween so as to bond the sheets are equal in outer diameter, rotate at the same rotation frequency, and are always opposed mutually at the same portions, the rollers fit easily. Hence, the satisfactory bonding state between the first sheet and the second sheet can be maintained. 
     Still further, since the outer diameters of the first and third rollers are the same size and since the rollers are mutually opposed to each other at the same portions at all times, readjustment at the time of component exchange is made easy, and assembling accuracy is maintained easily. As a result, the quality of the manufactured composite sheet can be maintained constant. 
     Hence, even when the composite sheet is manufactured at higher speed, it is possible to manufacture the composite sheet having stable quality. 
     Preferably, at the first step, an outer diameter of the second roller is made equal to each outer diameter of the first roller and the third roller, the second roller is joined to the first roller with a second gear pair therebetween, and the second roller is made to rotate at the same rotation frequency as that of the first roller. 
     In this case, since the first roller and the second roller are joined mutually via the second gear pair, the relative rotation error between the first roller and the second roller is unchanged even when the rotation frequency is changed. Moreover, each of the recessed areas of the first roller corresponds one-to-one to each of the first projections of the second roller, while the first projections are inserted into and extracted from the recessed areas. Hence, the satisfactorily shaped state of the first sheet can be maintained. 
     Still further, since the outer diameters of the first and the second roller are the same size and since the first roller is opposed mutually to the second roller at the same portion at all times, readjustment at the time of component exchange is made easy, and assembling accuracy is maintained easily. As a result, the quality of the manufactured composite sheet can be maintained constant. 
     Hence, the composite sheet having more stable quality can be manufactured. 
     In a preferred embodiment, the composite sheet manufacturing method further has (iv) a fourth step of disposing a fourth roller having a plurality of second projections and a fifth roller so as to be adjacent to the first roller, rotating the fourth roller and the fifth roller in synchronization with the first roller, and making the second projections of the fourth roller to be inserted into or extracted from the recessed areas of the first roller in a state in which a clearance is provided between each second projection of the fourth roller and each recessed area of the first roller, (v) a fifth step of conveying the first sheet and the second sheet having been passed through the space between the first roller and the third roller and bonded to each other while supporting the first sheet and the second sheet on the outer circumferential face of the first roller, making the first sheet and the second sheet to be passed through a space between the first roller and the fourth roller, and then making the first sheet and the second sheet to be passed through a space between the first roller and the fifth roller, (vi) a sixth step of pushing the second sheet into the recessed areas of the first roller by the second projections of the fourth roller when the first sheet and the second sheet are passed through the space between the first roller and the fourth roller, thereby shaping the second sheet, and (vii) a seventh step of holding the first sheet and the second sheet between the first roller and the fifth roller when the first sheet and the second sheet are passed through the space between the first roller and the fifth roller, thereby strengthening the mutual bonding of the first sheet and the second sheet. At the fourth step, (C) an outer diameter of the fifth roller is made equal to each outer diameter of the first roller and the third roller, and (D) the fifth roller is joined to the first roller with a third gear pair therebetween, and the fifth roller is made to rotate at the same rotation frequency as that of the first roller. 
     In this case, a composite sheet in which both of the first sheet and the second sheet thereof are formed is manufactured easily at higher speed. Furthermore, even when the composite sheet is manufactured at higher speed, it is possible to manufacture the composite sheet having stable quality. 
     Preferably, at the fourth step, the outer diameter of the fourth roller is made equal to each outer diameter of the first roller and the third roller, the fourth roller is joined to the first roller with a fourth gear pair therebetween, and the fourth roller is made to rotate at the same rotation frequency as that of the first roller. 
     In this case, since the first roller and the fourth roller are joined mutually via the gears, the relative rotation error between the first roller and the fourth roller is unchanged even when the rotation frequency is changed. Moreover, each of the recessed areas of the first roller corresponds one-to-one to each of the second projections of the fourth roller, the projections being inserted into and extracted from the recessed areas. Hence, the satisfactorily shaped state of the second sheet can be maintained. 
     Still further, since the outer diameters of the first and the fourth roller are the same size and since the first roller is opposed mutually to the fourth roller at the same portion at all times, readjustment at the time of component exchange is made easy, and assembling accuracy is maintained easily. As a result, the quality of the manufactured composite sheet can be maintained constant. 
     Hence, the composite sheet having further more stable quality can be manufactured. 
     Effects of Invention 
     According to the present invention, the composite sheet can be manufactured easily at higher speed, and even when the composite sheet is manufactured at higher speed, the composite sheet having stable quality can be manufactured. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1  is a schematic view showing a composite sheet manufacturing device (Embodiment 1); 
         FIG. 2  is a schematic view showing the drive mechanism of the composite sheet manufacturing device (Embodiment 1); 
         FIG. 3  is a sectional view taken on line A-A of  FIG. 2  (Embodiment 1); 
         FIG. 4  is an enlarged sectional view showing the main part of the composite sheet manufacturing device (Embodiment 1); 
         FIG. 5  is a schematic view showing a composite sheet manufacturing device (Embodiment 2); 
         FIG. 6  is a schematic view showing the drive mechanism of the composite sheet manufacturing device (Embodiment 2); 
         FIG. 7  is a schematic view showing a composite sheet manufacturing device (Conventional Example 1); 
         FIG. 8  is a sectional view showing a composite sheet (Conventional Example 2); 
         FIG. 9  is an image view of the composite sheet (Conventional Example 2); and 
         FIG. 10  is a schematic view showing a composite sheet manufacturing device (Conventional Example 2). 
     
    
    
     MODE FOR CARRYING OUT THE INVENTION 
     Embodiments according to the present invention will be described below referring to the drawings. 
     Embodiment 1 
     A composite sheet manufacturing device and a composite sheet manufacturing method according to Embodiment 1 will be described referring to  FIGS. 1 to 4 . 
       FIG. 1  is a schematic view showing a configuration of a composite sheet manufacturing device  10 . As shown in  FIG. 1 , in the composite sheet manufacturing device  10 , second to fifth rollers  22 ,  24 ,  26  and  28  are disposed in this order so as to be adjacent to a first roller  20 . The rotation center lines  20   x ,  22   x ,  24   x ,  26   x  and  28   x  of the first to fifth rollers  20 ,  22 ,  24 ,  26  and  28  are parallel to one another, and the first to fifth rollers  20 ,  22 ,  24 ,  26  and  28  rotate in the directions indicated by arrows  20   r ,  22   r ,  24   r ,  26   r  and  28   r , respectively, in synchronization with one another. 
     Although the second to fifth rollers  22 ,  24 ,  26  and  28  can be disposed at appropriate intervals around the first roller  20 , in the case that they are disposed uniformly as shown in  FIG. 1 , the first to fifth rollers  20 ,  22 ,  24 ,  26  and  28  can easily perform high-speed rotation. 
       FIG. 4  is an enlarged sectional view showing the main part of the composite sheet manufacturing device  10 . As shown in  FIG. 4 , the first roller  20  has a first outer circumferential face  20   s  having a cylindrical shape, multiple recessed areas  20   a  retracted inward in the radial direction from the first outer circumferential face  20   s  and multiple seal projections  20   b  protruding outward in the radial direction from the outer circumferential face  20   s.    
     The second roller  22  has a second outer circumferential face  22   s  having a cylindrical shape and being opposed to the first outer circumferential face  20   s  of the first roller  20  and first projections  22   a  that are inserted into and extracted from the recessed areas  20   a  of the first roller  20  in a state in which a clearance is provided between each projection thereof and each recessed area  20   a  of the first roller  20 . 
     As shown in  FIG. 1 , the third roller  24  has a third outer circumferential face  24   s  having a cylindrical shape and being opposed to the first outer circumferential face  20   s  of the first roller  20 . 
     Like the second roller  22 , the fourth roller  26  has a fourth outer circumferential face  26   s  having a cylindrical shape and being opposed to the first outer circumferential face  20   s  of the first roller  20  and second projections  26   a  that are inserted into and extracted from the recessed areas  20   a  of the first roller  20  in a state in which a clearance is provided between each projection thereof and each recessed area  20   a  (see  FIG. 4 ) of the first roller  20 . The second projections  26   a  are preferably smaller than the first projections  22   a  of the second roller  22  in height and width. 
     Like the third roller  24 , the fifth roller  28  has a fifth outer circumferential face  28   s  having a cylindrical shape and being opposed to the first outer circumferential face  20   s  of the first roller  20 . 
     The outer diameters of the first to fifth rollers  20 ,  22 ,  24 ,  26  and  28  are the same size. The outer diameter of the first roller  20  is twice as large as the radius  20   k  (see  FIG. 4 ) ranging from the rotation center line  20   x  of the first roller  20  to the tip of the seal projection  20   b  (see  FIG. 4 ) of the first roller  20 . The outer diameter of the second roller  22  is twice as large as the radius  22   k  (see  FIG. 4 ) ranging from the rotation center line  22   x  of the second roller  22  to the tip of the first projection  22   a  of the second roller  22 . The outer diameter of the third roller  24  is the diameter of the third outer circumferential face  24   s  of the third roller  24 . The outer diameter of the fourth roller  26  is twice as large as the radius ranging from the rotation center line  26   x  of the fourth roller  26  to the tip of the second projection  26   a  (see  FIG. 4 ) of the fourth roller  26 . The outer diameter of the fifth roller  28  is the diameter of the fifth outer circumferential face  28   s  of the fifth roller  28 . 
       FIG. 2  is a schematic view showing the drive mechanism  11  of the composite sheet manufacturing device  10 , viewed in parallel to the rotation center lines  20   x ,  22   x ,  24   x ,  26   x  and  28   x  (see  FIG. 1 ). As shown in  FIG. 2 , in the drive mechanism  11 , second to fifth gears  32 ,  34 ,  36  and  38  are disposed around a first gear  30  so as to be engaged with the first gear  30 . The mechanism is configured so that the rotations of the first to fifth gears  30 ,  32 ,  34 ,  36  and  38  are transmitted to the first to fifth rollers  20 ,  22 ,  24 ,  26  and  28 , respectively. The mechanism may be configured so that multiple first gears  30  are provided and so that one of the second to fifth rollers  22 ,  24 ,  26  and  28  is engaged with one of the first gears and another one of the second to fifth rollers  22 ,  24 ,  26  and  28  is engaged with another one of the first gears. 
       FIG. 3  is a sectional view taken on line A-A of  FIG. 2 . As shown in  FIG. 3 , the first gear  30  is fixed to a first rotation shaft  40  that is rotatably supported by the frame  12  of the composite sheet manufacturing device  10  via a bearing  41 . The first rotation shaft  40  is joined to the first roller  20  via a shaft joint, not shown, whereby the rotation of the first gear  30  is transmitted to the first roller  20  and the first roller  20  rotates at the same rotation frequency as that of the first gear  30 . 
     Similarly, the second to fifth gears  32 ,  34 ,  36  and  38  are fixed to second to fifth rotation shafts  42 ,  44 ,  46  and  48  ( 42  and  46  are not shown) that are rotatably supported by the frame  12  of the composite sheet manufacturing device  10  via bearings  43 ,  45 ,  47  and  48  ( 43  and  47  are not shown), respectively. The second to fifth rotation shafts  42 ,  44 ,  46  and  48  are joined to the second to fifth rollers  20 ,  22 ,  24 ,  26  and  28 , respectively, via shaft joints, not shown, whereby the second to fifth rollers  20 ,  22 ,  24 ,  26  and  28  rotate at the same rotation frequency as that of the gears  32 ,  34 ,  36  and  38 . In other words, the third roller  24  is joined to the first roller  20  with a first gear pair composed of the gears  30  and  34  so that the third roller  24  rotates at the same rotation frequency as that of the first roller  20 . The second roller  22  is joined to the first roller  20  with a second gear pair composed of the gears  30  and  32  so that the second roller  22  rotates at the same rotation frequency as that of the first roller  20 . The fifth roller  28  is joined to the first roller  20  with a third gear pair composed of the gears  30  and  38  so that the fifth roller  28  rotates at the same rotation frequency as that of the first roller  20 . The fourth roller  26  is joined to the first roller  20  with a fourth gear pair composed of the gears  30  and  36  so that the fourth roller  26  rotates at the same rotation frequency as that of the first roller  20 . 
     The first to fifth gears  30 ,  32 ,  34 ,  36  and  38  may be joined to the first to fifth rollers  20 ,  22 ,  24 ,  26  and  28 , respectively, with reduction mechanisms having the same reduction ratio or speed increasing mechanisms having the same speed increasing ratio. 
     As shown in  FIG. 3 , a pulley  46  is fixed to the first rotation shaft  40 . The rotation of a drive motor, not shown, is transmitted to the pulley  46  via a timing belt  48 . 
     The numbers of the teeth of the gears  30 ,  32 ,  34 ,  36  and  38  are the same, and the first gear  30  is engaged with the second to fifth gears  32 ,  34 ,  36  and  38 . Hence, when the rotation is transmitted to the pulley  46  via the drive motor, not shown, the first gear  30  is rotated, and the second to fifth gears  32 ,  34 ,  36  and  38  are rotated at the same rotation frequency as that of the first gear  30 , whereby the first to fifth rollers  20 ,  22 ,  24 ,  26  and  28  are rotated at the same rotation frequency. 
     Although a good balance is attained in the case that the rotation of the drive motor is distributed from the first rotation shaft  40  to the other rotation shafts  42 ,  44 ,  46  and  48 , it is possible that the rotation of the drive motor is transmitted to one or two or more of the rotation shafts  42 ,  44 ,  46  and  48  other than the first rotation shaft  40  and that the rotation of the rotation shaft is distributed to the other rotation shafts. 
     As shown in  FIG. 1 , in the composite sheet manufacturing device  10 , a first sheet  2  and a second sheet  4  are fed, and a composite sheet  6  is manufactured and ejected. The composite sheet  6  has a configuration similar to that of the composite sheet  150  shown in  FIGS. 8 and 9 , wherein both the first sheet  2  and the second sheet  4  are shaped and the first sheet  2  and the second sheet  4  are bonded intermittently. Although appropriate materials may merely be selected as the materials of the first sheet  2  and the second sheet  4 , materials that are deformed and fused when heated, for example, nonwoven fabrics containing resin material, are preferably used. 
     As indicated by an arrow  2   f , the first sheet  2  is fed in between the first roller  20  and the second roller  22  via a first guide roller  50 . The first sheet  2  is supported by the outer circumferential face  20   s  of the first roller  20  and conveyed in synchronization with the rotation of the first roller  20 . 
     As indicated by an arrow  4   f , the second sheet  4  is superimposed onto the first sheet  2  via a second guide roll  52  and conveyed together with the first sheet  2 . 
     The superimposed first sheet  2  and second sheet  4  are passed through the space between the first roller  20  and the third roller  24 , the space between the first roller  20  and the fourth roller  26  and the space between the first roller  20  and the fifth roller  28  in this order, whereby the completed composite sheet  6  is ejected via a third guide roller  54  as indicated by an arrow  6   f.    
     When the first sheet  2  is passed through the space between the first roller  20  and the second roller  22 , the first sheet  2  is shaped by being pushed into the recessed areas  20   a  of the first roller  20  by the first projections  22   a  of the second roller  22 , thereby being shaped into a predetermined shape. 
     In the case of a configuration in which the first sheet  2  is held between the first outer circumferential face  20   s  of the first roller  20  and the second outer circumferential face  22   s  of the second roller  22  when the first sheet  2  is passed through the space between the first roller  20  and the second roller  22 , the first sheet  2  can be shaped easily, whereby this configuration is preferable. However, even in the case of a configuration in which the first sheet  2  is passed through between the first outer circumferential face  20   s  of the first roller  20  and the second outer circumferential face  22   s  of the second roller  22  with a clearance provided therebetween, it is possible to shape the first sheet  2 . 
     The first roller  20  is preferably configured so as to suction-hold the first sheet  2 . For example, the first outer circumferential face  20   s  and the recessed areas  20   a  (see  FIG. 4 ) of the first roller  20  are provided with air suction holes, not shown. 
     When the second sheet  4  is passed through the space between the first roller  20  and the fourth roller  26 , the second sheet  4  is shaped by being pushed into the recessed areas  20   a  (see  FIG. 4 ) of the first roller  20  by the second projections  26   a  of the fourth roller  26 , thereby being shaped into a predetermined shape. 
     The tips of the second projections  26   a  of the fourth roller  26  may be sharpened, and through holes may be formed in the shaped portions of the second sheet  4  using the second projections  26   a  of the fourth roller  26 . 
     A heater, not shown, is provided in the inside of each of the first roller  20 , the third roller  24  and the fifth roller  28 . Hence, when the first sheet  2  and the second sheet  4  are held between the seal projections  20   b  (see  FIG. 4 ) of the first roller  20  and the outer circumferential face  24   s  of the third roller  24 , the first sheet  2  and the second sheet  4  are bonded to each other by thermal fusion. Furthermore, when the first sheet  2  and the second sheet  4  having been bonded to each other are held between the seal projections  20   b  (see  FIG. 4 ) of the first roller  20  and the outer circumferential face  28   s  of the fifth roller  28 , the mutual bonding is strengthened. 
     The heater can be provided only in the first roller  20 , or the heater can be provided in only each of the third roller  24  and the fifth roller  28 . Furthermore, at least one of the first roller  20 , the third roller  24  and the fifth roller  28  can be heated by a heating means, such as a heater, provided outside. 
     The region where the first sheet  2  and the second sheet  4  make contact with each other can be bonded intermittently by providing the multiple seal projections  20   b  (see  FIG. 4 ) on the outer circumferential face  20   s  of the first roller  20 . However, the entire region where the first sheet  2  and the second sheet  4  make contact with each other can be bonded continuously by eliminating the seal projections  20   b  (see  FIG. 4 ) and by holding the first sheet  2  and the second sheet  4  between the first outer circumferential face  20   s  of the first roller  20  and the third outer circumferential face  24   s  of the third roller  24 . 
     Next, processing for manufacturing the composite sheet  6  using the composite sheet manufacturing device  10  will be described. 
     (1-1) First, the second roller  22  having the first projections  22   a  and the third roller  24  are disposed so as to be adjacent to the first roller  20  having the multiple recessed areas  20   a  formed on the outer circumferential face  20   s  thereof, the first roller  20 , the second roller  22  and the third roller  24  are rotated in synchronization with one another, and the first projections  22   a  of the second roller  22  are inserted into and extracted from the recessed areas  20   a  of the first roller  20  in a state in which a clearance is provided between each projection thereof and each recessed area  20   a  of the first roller  20 . The outer diameters of the first roller  20  and the third roller  24  are made equal, and the third roller  24  is joined to the first roller  20  with the first gear pair composed of the gears  30  and  34 , whereby the third roller  24  is rotated at the same rotation frequency as that of the first roller  20 . Moreover, the outer diameter of the second roller  22  is made equal to the outer diameters of the first roller  20  and the third roller  24 , and the second roller  22  is joined with the second gear pair composed of the gears  30  and  32 , whereby the second roller  22  is rotated at the same rotation frequency as that of the first roller  20 . The processing up to this step is a first step. 
     (1-2) Furthermore, the fourth roller  26  having the second projection  26   a  and the fifth roller  28  are disposed so as to be adjacent to the first roller  20 , the fourth roller  26  and the fifth roller  28  are rotated in synchronization with the first roller  20 , and the projections  26   b  of the fourth roller  26  are inserted into and extracted from the recessed areas  20   a  of the first projections  22   a  in a state in which a clearance is provided between each projection thereof and each recessed area  20   a  of the first roller  20 . The outer diameter of the fifth roller  28  is made equal to the outer diameters of the first roller  20  and the third roller  24 , and the fifth roller  28  is joined to the first roller  20  with the third gear pair composed of the gears  30  and  38 , whereby the fifth roller  28  is rotated at the same rotation frequency as that of the first roller  20 . Moreover, the outer diameter of the fourth roller  26  is made equal to the respective outer diameters of the first roller  20  and the third roller  24 , and the fourth roller  26  is joined to the first roller  20  with the fourth gear pair composed of the gears  30  and  36 , whereby the fourth roller  26  is rotated at the same rotation frequency as that of the first roller  20 . The processing up to this step is a fourth step. 
     (2) Next, the first sheet  2  is fed in between the first roller  20  and the second roller  22  that are rotating, conveyed while being supported by the outer circumferential face  20   s  of the first roller  20 , and then passed through the space between the first roller  20  and the third roller  24 . When the first sheet  2  is passed through the space between the first roller  20  and the third roller  24 , the first sheet  2  is shaped by being pushed into the recessed areas  20   a  of the first roller  20  by the first projections  22   a  of the second roller  22 . The processing up to this step is a second step. 
     (3) Next, the second sheet  4  is superimposed onto the first sheet  2  having been shaped, conveyed together with the first sheet  2 , and passed through the space between the first roller  20  and the third roller  24 . When the first sheet  2  and the second sheet  4  are passed through the space between the first roller  20  and the third roller  24 , the first sheet  2  and the second sheet  4  are held between the first roller  20  and the third roller  24 , whereby the first sheet  2  and the second sheet  4  are bonded to each other. The processing up to this step is a third step. 
     (4) Next, the first sheet  2  and the second sheet  4  having been passed through the space between the first roller  20  and the third roller  24  and bonded to each other are conveyed while being supported by the outer circumferential face  20   s  of the first roller  20 , are passed through the space between the first roller  20  and the fourth roller  26 , and then passed through the space between the first roller  20  and the fifth roller  28 . The processing up to this step is a fifth step. 
     (5) Next, when the first sheet  2  and the second sheet  4  are being passed through the space between the first roller  20  and the fourth roller  26 , the second sheet  4  is shaped by being pushed into the recessed areas  20   a  of the first roller  20  by the second projections  26   a  of the fourth roller  26 . The processing up to this step is a sixth step. 
     (6) Next, when the first sheet  2  and the second sheet  4  are passed through the space between the first roller  20  and the fifth roller  28 , the first sheet  2  and the second sheet  4  are held between the first roller  20  and the fifth roller  28 , whereby the mutual bonding of the first sheet  2  and the second sheet  4  is strengthened. The processing up to this step is a seventh step. 
     When the composite sheet  6  is manufactured by performing the above-mentioned steps, raised portions shaped by the first projections  22   a  of the second roller  22  are formed at the positions corresponding to the recessed areas  20   a  of the first roller  20 . Furthermore, bonded sections wherein the first sheet  2  and the second sheet  4  are bonded to each other are formed at the positions corresponding to the seal projections  20   b  of the first roller  20 . For example, the bonded sections are disposed in a scattered state around the raised portions. The portions in which the second sheet  4  is shaped by the second projection  26   a  of the fourth roller  26  are disposed inside the raised portions of the first sheet  2 . 
     As described above, in the composite sheet manufacturing device  10 , the first to fifth rollers  20 ,  22 ,  24 ,  26  and  28  being equal in outer diameter are joined to one another via the gears  30 ,  32 ,  34 ,  36  and  38  and are rotated at the same rotation frequency. The composite sheet  6  can be manufactured easily at higher speed and the composite sheet  6  having stable quality can be maintained even when the composite sheet  6  is manufactured at higher speed by using the composite sheet manufacturing device  10 . 
     More specifically, when the rotation frequency of the rollers become higher, problems such as the heat generation of the bearings and the vibration of the rollers will occur, whereby the degree of difficulty in technology rises. In the case of a configuration in which the rotation frequency of the rollers  22 ,  24 ,  26  and  28  other than the first roller  20  are raised higher than the rotation frequency of the first roller  20 , when the rotation frequency of the first roller  20  is made higher, technical problems will occur in the other rollers  22 ,  24 ,  26  and  28  that rotate at the rotation frequency higher than that of the first roller  20 ; hence, the rotation frequency of the first roller  20  is limited to a rotation frequency that is lower than the upper limit rotation frequency at which technical problems do not occur in the other rollers  22 ,  24 ,  26  and  28 . On the other hand, in the case of a configuration in which the first to fifth rollers  20 ,  22 ,  24 ,  26  and  28  are rotated at the same rotation frequency, the rotation frequency of the first roller  20  can be made higher to the rotation frequency coincident with the upper limit rotation frequency of the other rollers  22 ,  24 ,  26  and  28 . Hence, the rotation frequency of the first roller  20  is made higher easily. As the rotation frequency of the first roller  20  is made higher, the composite sheet  6  can be manufactured at higher speed. 
     Hence, it is easy to manufacture the composite sheet  6  at higher speed. 
     Furthermore, as the relative rotation error between the first roller  20  and the other rollers  22 ,  24 ,  26  and  28  becomes larger, the quality of the composite sheet  6  will be degraded, for example, due to the displacement of shaping and bonding positions. In the case that the first roller  20  and the other rollers  22 ,  24 ,  26  and  28  are rotated and driven separately and controlled so as to be synchronized mutually, if the rotation frequency is made higher, the relative rotation error between the first roller  20  and the other rollers  22 ,  24 ,  26  and  28  becomes larger, for example, due to delay in control, whereby it becomes difficult to maintain the quality of the composite sheet  6 . On the other hand, in the case that the first roller  20  and the other rollers  22 ,  24 ,  26  and  28  are joined mutually via the gears  30 ,  32 ,  34 ,  36  and  38 , since the relative rotation error between the first roller  20  and the other rollers  22 ,  24 ,  26  and  28  is unchanged even when the rotation frequency is changed, whereby the quality of the composite sheet  6  can be maintained even when the rotation frequency of the first roller  20  is made higher. 
     Moreover, since the first roller  20  and the third and fifth rollers  24  and  28  that hold the first and second sheets  2  and  4  therebetween so as to bond the sheets are equal in outer diameter, rotate at the same rotation frequency and are always opposed mutually at the same portions, the rollers fit easily. Hence, the satisfactory bonding state between the first sheet  2  and the second sheet  4  can be maintained. 
     What&#39;s more, each of the recessed areas  20   a  of the first roller  20  corresponds one-to-one to each of the first projections  22   a  of the second roller  22  and each of the second projections  26   a  of the fourth roller  26 , the first and second projections  20   a  and  26   a  being inserted into the recessed areas  20   a . Hence, the satisfactorily shaped states of the first and second sheets  2  and  4  can be maintained. 
     Still further, since the first to fifth rollers  20 ,  22 ,  24 ,  26  and  28  are equal in outer diameter and since the first roller  20  is opposed mutually to the second to fifth rollers  22 ,  24 ,  26  and  28  at the same portions at all times, readjustment at the time of component exchange is made easy, and assembling accuracy is maintained easily. As a result, the quality of the manufactured composite sheet  6  can be maintained constant. 
     Hence, even when the composite sheet  6  is manufactured at higher speed, it is possible to manufacture the composite sheet  6  having stable quality. 
     Next, a modification of Embodiment 1 will be described. 
     Modification 1 
     Modification 1 is configured such that the fourth roller  26  and the fifth roller  28  in the configuration of Embodiment 1 are eliminated. The second roller  22  and the third roller  24  may merely be disposed at appropriate angles around the first roller  20 . 
     In this case, the fifth to seventh steps in the above-mentioned processing for manufacturing the composite sheet are not required. 
     As in the case of Embodiment 1, in Modification 1, the composite sheet can be manufactured easily at higher speed, and even when the composite sheet is manufactured at higher speed, the composite sheet having stable quality can be manufactured. 
     Embodiment 2 
     A manufacturing device and a manufacturing method for manufacturing a composite sheet according to Embodiment 2 will be described referring to  FIGS. 5 and 6 . Embodiment 2 is different from Embodiment 1 in that the outer diameters of the second and fourth rollers are different from the outer diameter of the first roller. In the following description, attention is paid to the differences from Embodiment 1, and the same components as those in Embodiment 1 are designated by the same reference numerals and signs. 
       FIG. 5  is a schematic view showing a configuration of a composite sheet manufacturing device  10   a . As shown in  FIG. 5 , as in the case of the composite sheet manufacturing device  10  according to Embodiment 1, in the composite sheet manufacturing device  10   a , second to fifth rollers  23 ,  24 ,  27  and  28  are disposed in this order so as to be adjacent to the first roller  20 . The rotation center lines  20   x ,  23   x ,  24   x ,  27   x  and  28   x  of the first to fifth rollers  20 ,  23 ,  24 ,  27  and  28  are parallel to one another, and the first to fifth rollers  20 ,  23 ,  24 ,  27  and  28  rotate in the directions indicated by arrows  20   r ,  23   r ,  24   r ,  27   r  and  28   r , respectively, in synchronization with one another. As indicated by arrows  2   f  and  4   f , the first and second sheets  2  and  4  are fed via the first and second guide rollers  50  and  52  and conveyed through a predetermined path along the outer circumferential face  20   s  of the first roller  20  in synchronization with the rotation of the first roller  20 , and then shaped into a predetermined shape by the first and second projections  23   a  and  27   a  protruding from the second and fourth outer circumferential faces  23   s ,  27   s  of the second and fourth rollers  23  and  27  and bonded to each other. The completed composite sheet  6  is ejected via the third guide roller  54  as indicated by an arrow  6   f.    
     The outer diameters of the third and fifth rollers are equal to the outer diameter of the first roller  20 . Unlike the case of Embodiment 1, the outer diameters of the second and fourth rollers  23  and  27  are different from the outer diameter of the first roller  20  and are preferably smaller than the outer diameter of the first roller  20 . For example, the outer diameters of the second and fourth rollers  23  and  27  are approximately ⅓ of the outer diameter of the first roller  20 . 
       FIG. 6  is a schematic view showing the drive mechanism  11   a  of the composite sheet manufacturing device  10   a , viewed in parallel to the rotation center lines  20   x ,  23   x ,  24   x ,  27   x  and  28   x  (see  FIG. 5 ). As shown in  FIG. 6 , as in the case of the drive mechanism  11  according to Embodiment 1, in the drive mechanism  11   a , second to fifth gears  33 ,  34 ,  37  and  38  are disposed around the first gear  30  so as to be engaged with the first gear  30 . The mechanism is configured so that the rotations of the first to fifth gears  30 ,  33 ,  34 ,  37  and  38  are transmitted to the first to fifth rollers  20 ,  23 ,  24 ,  27  and  28 , respectively. The numbers of the teeth of the first, third and fifth gears  30 ,  34  and  38  are the same. The numbers of the teeth of the second and fourth gears  33  and  37  are different from the number of the teeth of the first roller  20  and are preferably less than the number of the teeth of the first gear  30 . 
     Instead of the second and fourth gears  33  and  37 , timing belts or the like may be used. Furthermore, the second and fourth rollers  23  and  27  and the first, third and fifth rollers  20 ,  24  and  28  may be driven separately. 
     Next, processing for manufacturing the composite sheet  6  using the composite sheet manufacturing device  10   a  will be described. 
     (1-1) First, the second roller  23  having the first projections  23   a  and the third roller  24  are disposed so as to be adjacent to the first roller  20  having the multiple recessed areas  20   a  formed on the outer circumferential face  20   s  thereof, the first roller  20 , the second roller  23  and the third roller  24  are rotated in synchronization with one another, and the first projections  23   a  of the second roller  23  are inserted into and extracted from the recessed areas  20   a  of the first roller  20  in a state in which a clearance is provided between each projection thereof and each recessed area  20   a  of the first roller  20 . The outer diameters of the first roller  20  and the third roller  24  are made equal, and the third roller  24  is joined to the first roller  20  with the first gear pair composed of the gears  30  and  34 , whereby the third roller  24  is rotated at the same rotation frequency as that of the first roller  20 . The processing up to this step is a first step. 
     (1-2) Furthermore, the fourth roller  26  having the second projection  26   a  and the fifth roller  28  are disposed so as to be adjacent to the first roller  20 , the fourth roller  26  and the fifth roller  28  are rotated in synchronization with the first roller  20 , and the projections  26   b  of the fourth roller  26  are inserted into and extracted from the recessed areas  20   a  of the first projections  22   a  in a state in which a clearance is provided between each projection thereof and each recessed area  20   a  of the first roller  20 . The outer diameter of the fifth roller  28  is made equal to the outer diameters of the first roller  20  and the third roller  24 , the fifth roller  28  is joined to the first roller  20  with the third gear pair composed of the gears  30  and  38 , and the fifth roller  28  is rotated at the same rotation frequency as that of the first roller  20 . The processing up to this step is a fourth step. 
     (2) Next, the first sheet  2  is fed in between the first roller  20  and the second roller  22  that are rotating, conveyed while being supported by the outer circumferential face  20   s  of the first roller  20 , and then passed through the space between the first roller  20  and the third roller  24 . When the first sheet  2  is passed through the space between the first roller  20  and the third roller  23 , the first sheet  2  is shaped by being pushed into the recessed areas  20   a  of the first roller  20  by the first projections  23   a  of the second roller  23 . The processing up to this step is a second step. 
     (3) Next, the second sheet  4  is superimposed onto the first sheet  2  having been shaped, conveyed together with the first sheet  2 , and passed through the space between the first roller  20  and the third roller  24 . When the first sheet  2  and the second sheet  4  are passed through the space between the first roller  20  and the third roller  24 , the first sheet  2  and the second sheet  4  are held between the first roller  20  and the third roller  24 , whereby the first sheet  2  and the second sheet  4  are bonded to each other. The processing up to this step is a third step. 
     (4) Next, the first sheet  2  and the second sheet  4  having been passed through the space between the first roller  20  and the third roller  24  and bonded to each other are conveyed while being supported by the outer circumferential face  20   s  of the first roller  20 , are passed through the space between the first roller  20  and the fourth roller  26 , and then passed through the space between the first roller  20  and the fifth roller  28 . The processing up to this step is a fifth step. 
     (5) Next, when the first sheet  2  and the second sheet  4  are being passed through the space between the first roller  20  and the fourth roller  26 , the second sheet  4  is shaped by being pushed into the recessed areas  20   a  of the first roller  20  by the second projections  26   a  of the fourth roller  26 . The processing up to this step is a sixth step. 
     (6) Next, when the first sheet  2  and the second sheet  4  are passed through the space between the first roller  20  and the fifth roller  28 , the first sheet  2  and the second sheet  4  are held between the first roller  20  and the fifth roller  28 , whereby the mutual bonding of the first sheet  2  and the second sheet  4  is strengthened. The processing up to this step is a seventh step. 
     The composite sheet  6  can be manufactured by performing the above-mentioned steps (1) to (6). 
     As described above, in the composite sheet manufacturing device  10   a , the first, third and fifth rollers  20 ,  24  and  28  being equal in outer diameter are rotated at the same rotation frequency via the first, third and fifth gears  30 ,  34  and  38 . The composite sheet  6  can be manufactured easily at higher speed and the composite sheet  6  having stable quality can be maintained even when the composite sheet  6  is manufactured at higher speed by using the composite sheet manufacturing device  10   a.    
     More specifically, as described above, when the rotation frequency of the rollers become higher, problems such as the heat generation of the bearings and the vibration of the rollers will occur, whereby the degree of difficulty in technology rises. In the case of a configuration in which the rotation frequency of the rollers  23 ,  24 ,  27  and  28  other than the first roller  20  are raised higher than the rotation frequency of the first roller  20 , when the rotation frequency of the first roller  20  is made higher, technical problems will occur in the other rollers  23 ,  24 ,  27  and  28  that rotate at the rotation frequency higher than that of the first roller  20 ; hence, the rotation frequency of the first roller  20  is limited to a rotation frequency lower than the upper limit rotation frequency at which technical problems do not occur in the other rollers  23 ,  24 ,  27  and  28 . 
     The sheets  2  and  4  are held between the first roller  20  and each of the third roller  23  and the fifth roller  28 ; however, since the projections  23   a  and  27   a  of the second and fourth rollers  23  and  27  are inserted into and extracted from the recessed areas  20   a  of the first roller  20  in a state in which a clearance is provided between each projection thereof and each recessed area  20   a  of the first roller  20 ; hence, the upper limit rotation frequency of the third and fifth rollers  24  and  28  is lower than the upper limit rotation frequency of the second and fourth rollers  23  and  27 . Hence, in comparison with the conventional configuration in which the rotation frequency of the first roller is higher than the rotation frequency of the other rollers, the rotation frequency of the first roller can be made higher than that in the conventional configuration by simply making the rotation frequency of the third and fifth rollers  24  and  28  equal to the rotation frequency of the first roller  20 . 
     Hence, the composite sheet  6  is manufactured easily at higher speed. 
     Since the rotation frequency of the second and fourth rollers  23  and  27  can be made higher than the rotation frequency of the first roller  20 , the second and fourth rollers  23  and  27  and the gears  33  and  37  for transmitting the rotation to the second and fourth rollers  23  and  27  can be made smaller. Hence, the composite sheet manufacturing device  10   a  can be made smaller than the composite sheet manufacturing device  10  according to Embodiment 1 in size. 
     Furthermore, as the relative rotation error between the first roller  20  and the other rollers  23 ,  24 ,  27  and  28  becomes larger, the quality of the composite sheet  6  will be degraded, for example, due to the displacement of shaping and bonding positions. In the case that the first roller  20  and the other rollers  23 ,  24 ,  27  and  28  are rotated and driven separately and controlled so as to be synchronized mutually, if the rotation frequency is made higher, the relative rotation error between the first roller  20  and the other rollers  23 ,  24 ,  27  and  28  becomes larger, for example, due to delay in control, whereby it becomes difficult to maintain the quality of the composite sheet  6 . On the other hand, in the case that the first roller  20  and the other rollers  23 ,  24 ,  27  and  28  are joined mutually via the gears  30 ,  33 ,  34 ,  37  and  38 , since the relative rotation error between the first roller  20  and the other rollers  23 ,  24 ,  27  and  28  is unchanged even when the rotation frequency is changed, whereby the quality of the composite sheet  6  can be maintained even when the rotation frequency of the first roller  20  is made higher. 
     Moreover, since the first roller  20  and the third and fifth rollers  24  and  28  that hold the first and second sheets  2  and  4  therebetween so as to bond the sheets are equal in outer diameter, rotate at the same rotation frequency, and are always opposed mutually at the same portions, the rollers fit easily. Hence, the satisfactory bonding state between the first sheet  2  and the second sheet  4  can be maintained. 
     Still further, since the first, third and fifth rollers  20 ,  24  and  28  are equal in outer diameter and since the first roller  20  is opposed mutually to the third and fifth rollers  24  and  28  at the same portions at all times, readjustment at the time of component exchange is made easy, and assembling accuracy is maintained easily. As a result, the quality of the manufactured composite sheet  6  can be maintained constant. 
     Hence, even when the composite sheet  6  is manufactured at higher speed, it is possible to manufacture the composite sheet  6  having stable quality. 
     Next, a modification of Embodiment 2 will be described. 
     Modification 2 
     Modification 2 is configured such that the fourth roller  27  and the fifth roller  28  in the configuration of Embodiment 2 are eliminated. The second roller  23  and the third roller  24  may merely be disposed at appropriate angles around the first roller  20 . 
     In this case, the fifth to seventh steps in the above-mentioned processing for manufacturing the composite sheet are not required. 
     As in the case of Embodiment 2, in Modification 2, the composite sheet can be manufactured easily at higher speed, and even when the composite sheet is manufactured at higher speed, the composite sheet having stable quality can be manufactured. 
     CONCLUSION 
     With the composite sheet manufacturing device and manufacturing method described above, the composite sheet can be manufactured easily at higher speed, and even when the composite sheet is manufactured at higher speed, the composite sheet having stable quality can be manufactured. 
     The present invention is not limited to the above-mentioned embodiments and can be modified variously and embodied. 
     DESCRIPTION OF REFERENCE NUMERALS 
     
         
         
           
               2  first sheet 
               4  second sheet 
               6  composite sheet 
               10  composite sheet manufacturing device 
               20  first roller 
               20   a  recessed area 
               20   s  first outer circumferential face 
               22 ,  23  second roller 
               22   a ,  23   a  first projection 
               22   s ,  23   s  second outer circumferential face 
               24  third roller 
               24   s  third outer circumferential face 
               26 ,  27  fourth roller 
               26   a ,  27   a  second projection 
               26   s ,  27   s  fourth outer circumferential face 
               28  fifth roller 
               28   s  fifth outer circumferential face 
               30 ,  32 ,  33 ,  34 ,  36 ,  37 ,  38  gear