Patent Publication Number: US-10315875-B2

Title: Accumulation device

Description:
PRIORITY APPLICATIONS 
     This application is a U.S. National Stage Filing under 35 U.S.C. 371 from International Application No. PCT/JP2016/052413, filed on 28 Jan. 2016, and published as WO2016/157973 on 6 Oct. 2016, which claims the benefit of priority to Japanese Application No. 2015-067362, filed on 27 Mar. 2015; which applications and publication are incorporated herein by reference in their entirety. 
     TECHNICAL FIELD 
     The present invention relates to an accumulation device disposed between an infeed unit that carries in a long belt-like substrate and an outfeed unit that carries out the substrate and capable of accumulating a surplus of the substrate caused by a difference between a substrate infeed rate and a substrate outfeed rate. 
     BACKGROUND 
     An accumulation device  100  as illustrated in  FIG. 14  is known. The accumulation device  100  may be used for a system designed for applying, to a long belt-like substrate S such as a resin film supplied from a supply reel, predetermined processing such as inspection and machining (e.g., printing, perforating) of the substrate S, and thereafter taking up the substrate S with a winding reel. In such a system, the accumulation device  100  is disposed between a processing device that performs the predetermined processing and a winding unit that winds up the substrate processed by the processing device. 
     As illustrated in  FIG. 14A , the accumulation device  100  includes a plurality of fixed rollers  102  which are arranged in parallel to each other upward in the vertical direction such that they are spaced from each other, and a plurality of movable rollers  104  which are arranged downward in the vertical direction from the respective fixed rollers  102  such that they are spaced from and parallel to each other. Each of the fixed rollers  102  is rotatably supported by a fixed frame (not shown) at its opposite ends. Each of the movable rollers  104 , on the other hand, is rotatably supported by a pair of support members  106  (one of which is shown) at its opposite ends. The support member  106  is configured to be capable of ascending and descending toward and away from the fixed rollers  102 . 
     In the accumulation device  100  configured as described above, the substrate S is transported from upstream (the right side in  FIG. 14 ) toward downstream (the left side in  FIG. 14 ) while being wound around each fixed roller  102  and each movable roller  104  alternately. A load F acts on the support member  106  downwardly in the vertical direction. During steady operation in which the substrate S is continuously transported at a constant rate with the load F acting on the support member  106 , the substrate S is transported while a constant tensile force is being applied the substrate S. 
     When a downstream device, such as the winding unit, located downstream of the accumulation device  100 , stops for replacement of a reel, for example, outfeed of the substrate S stops downstream of the accumulation device  100  as illustrated in  FIG. 14A ; however, the substrate S is continuously fed from upstream of the accumulation device  100 . In this case, the accumulation device  100  moves the support member  106  supporting the movable rollers  104  away from the fixed rollers  102 ; that is, downward in the vertical direction (in the direction of arrow G). This allows the substrate S, being continuously fed in with outfeed the substrate S being stopped, to be accumulated in the accumulation device  100 . 
     When the downstream device starts operation to resume outfeed of the substrate S from the accumulation device  100 , a substrate outfeed rate by an outfeed roller, which is not shown, is set to be higher than that in steady operation, and, as illustrated in  FIG. 14A , the substrate S accumulated in the accumulation device  100  is fed out while the support member  106  supporting the movable rollers  104  is being moved upward. When the support member  106  ascends to a home position in steady operation, the operation state is placed in the steady operation state with the outfeed rate of the substrate S being set to be the same as the infeed rate. 
     Reference documents related to such an accumulation device include Patent Documents 1 and 2 listed below. The accumulation devices disclosed in these documents are disposed between a substrate feeding device, which is an upstream device, and a labeling device, which is a downstream device. The accumulation devices are capable of continuously transporting a cylindrical label folded in a sheet form to the labeling device at a constant rate while accumulating the label substrate during the steady operation, and continuously feeding out the label substrate accumulated in the accumulation device while infeed of the label substrate is suspended because of replacement of an elongate roll of label substrate of the substrate feeding device, thereby allowing continuous operations of the labeling device. 
     CITATION LIST 
     Patent Literature 
     
         
         PATENT DOCUMENT 1: JP 2007-62884 A 
         PATENT DOCUMENT 2: JP 2007-161409 A 
       
    
     SUMMARY 
     Technical Problem 
     When the movable rollers  104  move downward and the accumulation action is performed in the accumulation device  100  described above, the structure in which the respective movable rollers  104  are supported by the same support member  106  causes the following problem. When the moving responsiveness of the support member  106  is slightly slow, the tensile force of the substrate S rapidly lowers and the substrate S may be loosened and float off momentarily with respect to one or more movable rollers  104  located upstream in the substrate transporting direction (the right side in  FIG. 14 ). This tendency becomes more noticeable as the number of movable rollers  104  increases. 
     The substrate S, floating off the movable roller  104  as described above, draws in an air layer between the substrate S and the movable roller  108   a , and consequently meanders or twists, resulting in generation of wrinkles and ruptures in the substrate S. Even when such an air layer is not drawn in, fluctuation in the tensile force of the substrate S which is being transported may cause the substrate S to meander or twist, leading to generation of wrinkles and ruptures of the substrate S. In particular, a cylindrical label substrate formed by folding a long resin film such that opposite ends thereof are overlapped and joined together has a large thickness in the joined portion. This would likely cause the substrate S to meander or twist during transportation thereby causing wrinkles and separation during transportation. A cylindrical label substrate may also expand in a balloon shape because of air accumulated within the cylindrical substrate at a location immediately before each roller around which the substrate is wound, causing a hindrance to transportation of the substrate. 
     To address these disadvantages, crown-shaped rollers having a greater diameter in the center region in the axial direction than diameters at the ends, or rollers having steps formed thereon to regulate meandering of the substrate S, for example, have been used as the fixed rollers  102  and the movable rollers  104 . However, problems such as bending or buckling of the substrate occur because the strength of the substrate lowers as the thickness decreases, and the above disadvantages remained unresolved. 
     The present invention is aimed at providing an accumulation device capable of reducing fluctuation in tensile force of a substrate to prevent the substrate from floating off a movable roller during an accumulation operation, thereby regulating occurrence of wrinkles and ruptures in the accumulated substrate. 
     Solution to Problem 
     An accumulation device in accordance with one aspect of the invention includes an infeed unit configured to feed in a substrate having a long belt-like shape, an outfeed unit configured to feed out the substrate, and an accumulation unit disposed between the infeed unit and the outfeed unit and capable of accumulating a surplus of the substrate generated by a difference between an infeed rate of the substrate and an outfeed rate of the substrate. The accumulation unit includes a set of first rollers including a plurality of rotatable first rollers spaced from each other and arranged in parallel to each other, a set of second rollers including a plurality of rotatable second rollers spaced from each other and arranged in parallel to each other, the set of second rollers being movable toward and away from the set of first rollers, and the substrate is configured to be transported while being wound alternately around the first rollers and the second rollers and to be accumulated by relative movement of the set of first rollers and the set of second rollers in a direction away from each other. Each of the second rollers is supported by a support member that is movable with respect to the set of first rollers, and at least a part of the second rollers are urged independently in a direction away from the set of first rollers by elastic members provided respectively corresponding to the second rollers or by self-weight of the second rollers and a movable member configured to support the second rollers movably with respect to the support members. 
     In the above accumulation device, each of the first rollers and the second rollers preferably includes a roller portion, and a shaft configured to rotatably support the roller portion via a bearing member. Each of the first rollers and the second rollers preferably further includes a tendency mechanism configured to rotate the shaft at a rotation rate identical with a rotation rate of the roller portion in a rotation direction identical with a rotation direction of the roller portion. 
     Advantageous Effects of Invention 
     In the accumulation device according to an embodiment of the invention, each of the second rollers is supported by a support structure which is movable with respect to the set of first rollers, and is also urged independently by the elastic member or the self-weight in the direction away from the set of first rollers. This structure allows the second rollers to move following the substrate which attempts to float off the second rollers during the accumulation operation, by the urging force of the elastic member or the self-weight, and to thereby keep contact with the substrate. The structure thus absorbs fluctuation in the tensile force of the substrate and also prevents an air layer from being drawn in between the substrate and the second rollers, thereby reducing wrinkles and ruptures generated by meandering or twisting of the substrate. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1  illustrates a whole structure of a film processing system including an accumulation device according to one embodiment of the present invention. 
         FIG. 2  illustrates a tensioning unit of the accumulation device illustrated in  FIG. 1  seen from the downstream side in the substrate transportation direction. 
         FIG. 3  is a side view illustrating a drive mechanism of an accumulation unit of the accumulation device. 
         FIG. 4  is a cross sectional view taken along line C-C in  FIG. 3  with arrow indication. 
         FIG. 5  is a perspective view illustrating a tendency mechanism disposed on each roller of the accumulation unit. 
         FIG. 6  is a graph showing a tendency of the tensile force acting on the substrate in the accumulation unit. 
         FIG. 7  is a flowchart showing steady operation control executed by a controller illustrated in  FIG. 1 . 
         FIG. 8  is a flowchart showing accumulation operation control executed by the controller illustrated in  FIG. 1 . 
         FIG. 9  is a flowchart showing the accumulation operation control continuing from  FIG. 8  executed by the controller illustrated in  FIG. 1 . 
         FIG. 10  is a diagram illustrating the accumulation operation state in the accumulation device. 
         FIG. 11  is a diagram illustrating an accumulation device including independent suspension lower rollers in the accumulation unit. 
         FIG. 12  is a cross sectional view taken along line D-D in  FIG. 11 . 
         FIG. 13  is a diagram illustrating a state in which the accumulation unit illustrated in  FIG. 11  performs the accumulation operation. 
         FIG. 14  illustrates an example prior art accumulation device:  FIG. 14A  illustrates the steady operation state. 
         FIG. 14B  illustrates the outfeed stop state. 
         FIG. 14C  illustrates the outfeed acceleration state. 
     
    
    
     DESCRIPTION OF EMBODIMENTS 
     Embodiments according to the present invention will be described in detail below with reference to the attached drawings. In the following description, specific shapes, materials, numerical values, and directions, for example, are only examples for facilitating understanding of the present invention, and may be modified as appropriate in accordance with usage, purposes, and specification, for example. When the following description includes a plurality of embodiments and modifications, it is assumed that features thereof are used in appropriate combinations. 
     The following description describes an example in which a long belt-like substrate to be transported via an accumulation device is a cylindrical resin film in a folded state, which is obtained by joining opposite ends of a printed heat-shrinkable film. However, the substrate is not limited to this example, and may be formed of a material other than a resin film, such as paper, fabric, or metal. 
       FIG. 1  illustrates a whole structure of a film processing system  1  including an accumulation device  10  according to one embodiment of the present invention. In  FIG. 1  (also in  FIG. 2  and other drawings), the horizontal direction along the transportation direction of a substrate S is indicated with an arrow X, the direction orthogonal to the arrow X within the horizontal plane is indicated with an arrow Y, and the vertical direction orthogonal to the arrow X and the arrow Y is indicated with an arrow Z. 
     The film processing system  1  includes a film supply unit  2  for supplying a substrate S which is a long belt-like resin film, a processor  4  for applying predetermined processing to the substrate S supplied from the film supply unit  2 , and a winding unit  5  for taking up the substrate S having been subjected to the predetermined processing via the accumulation device  10 . 
     The film supply unit  2  includes a supply reel  3  wound with the substrate S. The supply reel  3  unreels the substrate S while being driven to rotate in the direction of an arrow A. 
     The film substrate S unreeled from the supply unit  2  is supplied to the processor  4 . The processor  4  applies predetermined processing to the substrate S supplied from the film supply unit  2 . The “predetermined processing” as used herein includes, for example, applying image processing to a captured image of the substrate S for inspecting the substrate S, or treating the substrate S by printing and perforating, for example. 
     The cylindrical substrate S folded in a sheet form, which is supplied from the processor  4 , is transported, via the accumulation device  10 , to the winding unit  5 . The winding unit  5  winds the substrate S by a winding reel  6  which is driven to rotate in the direction of an arrow B. The winding unit  5  includes a substrate winding amount detection sensor  7  disposed at a location opposite the outer circumference of the winding reel  6 . The substrate winding amount detection sensor  7  detects that the amount of the substrate S taken up and wound around the winding reel  6  reaches a predetermined amount. The detection value from the substrate winding amount detection sensor  7  is transmitted, as a signal, to a controller  90  of the accumulation device  10 . 
     The accumulation device  10  includes, from upstream to downstream in the transportation direction of the substrate S, an infeed unit  20 , a tensioning unit  30 , an accumulation unit  50 , an outfeed unit  80 , and the controller  90 , in this order. 
     The infeed unit  20  has a function to feed the substrate S sent out from the processor  4  into the accumulation device  10 . The infeed unit  20  is located closest to the upstream side in the transportation direction of the substrate within the accumulation device  10 . The infeed unit  20  includes a drive roller  22  driven to rotate by an infeed motor M 1 , and a slave roller  24  which forms a nip with the drive roller  22  and can rotate as a slave unit. In the infeed unit  20 , the infeed motor M 1  is preferably formed of a servo motor, for example. Thus, when the infeed motor M 1  drives the drive roller  22  to rotate in the infeed unit  20 , the substrate S caught between the drive roller  22  and the slave roller  24  is fed to the tensioning unit  30  of the accumulation device  10 . 
     The infeed unit  20  further includes a rotation rate detection sensor  26  for detecting the rotation rate of the slave roller  24 . The detection value from the rotation rate detection sensor  26  is transmitted, as a signal S 1 , to the controller  90 , which can use the signal S 1  for computation of the infeed rate of the substrate S. However, when the infeed motor M 1  itself has a function to detect the rotation rate and the rotation rate of the drive roller  22  can therefore be derived from the rotation rate of the infeed motor M 1 , the infeed rate of the substrate S can be calculated based on the rotation rate of the infeed motor M 1 . Therefore, in such a case, the rotation rate detection sensor  26  may be omitted. 
     The outfeed unit  80  has a function to feed out the substrate S from the accumulation device  10 . The outfeed unit  80  is located closest to the downstream side in the transportation direction of the substrate within the accumulation device  10 . The outfeed unit  80  includes a drive roller  82  which is driven to rotate by an outfeed motor M 2 , and a slave roller  84  which forms a nip with the drive roller  82  and can rotate as a slave unit. In the outfeed unit  80 , the outfeed motor M 2  is preferably formed of a servo motor, for example. Thus, when the outfeed motor M 2  drives the drive roller  82  to rotate in the outfeed unit  80 , the substrate S caught between the drive roller  82  and the slave roller  84  is sent out from the accumulation device  10  toward the winding unit  5 . 
     The outfeed unit  80  further includes a rotation rate detection sensor  86  for detecting the rotation rate of the slave roller  84 . The detection value from the rotation rate detection sensor  86  is transmitted, as a signal S 2 , to the controller  90 , which can use the signal S 2  for computation of the outfeed rate of the substrate S. However, when the outfeed motor M 2  itself has a function to detect the rotation rate and the rotation rate of the drive roller  82  can therefore be derived from the rotation rate of the outfeed motor M 2 , the outfeed rate of the substrate S can be calculated based on the rotation rate of the outfeed motor M 2 . Therefore, in such a case, the rotation rate detection sensor  86  may be omitted. 
     The tensioning unit  30  is disposed between the infeed unit  20  and the outfeed unit  80  toward the upstream side with respect to the substrate transportation direction. More specifically, the tensioning unit  30  is disposed next to the infeed unit  20  on the downstream side in the substrate transportation direction. 
     The tensioning unit  30  includes a plurality of rotatable fixed rollers  32  disposed spaced from and parallel to each other, and a plurality of rotatable movable rollers  34  which are disposed parallel to the fixed rollers  32  and are movable closer to or away from the fixed rollers  32 . In the present embodiment, three fixed rollers  32  and three movable rollers  34  are provided. However, the tensioning unit  30  is not limited to this example, and may be configured to include at least two fixed rollers  32  and at least one movable roller  34  disposed at a location below and between these two fixed rollers  32  so as to be movable in the vertical direction or upward and downward directions. 
     The substrate S sent out from the infeed unit  20  is guided by an outer circumferential surface of a support roller  36  which is rotatably disposed, so that the transportation direction of the substrate S is changed from the horizontal direction to the vertical direction. In the tensioning unit  30 , the substrate S winds around the fixed rollers  32  and the movable rollers  34  alternately. 
       FIG. 2  illustrates the tensioning unit  30  of the accumulation device  10  illustrated in  FIG. 1  seen from the downstream side in the substrate transportation direction. Referring to  FIG. 1  and  FIG. 2 , the opposite ends of each fixed roller  32  are rotatably supported by fixed frames  12  and  14  of the accumulation device  10 , respectively. Further, the opposite ends of each movable roller  34  are rotatably supported by a support member  38 . The support member  38  is disposed so as to be movable along the direction of an arrow E (or the vertical direction Z) by a guide rail, which is not shown, fixed to the accumulation device  10 . The movable rollers  34  and the support member  38  form a movable unit  40 . In the following description, the movable rollers  34  may be referred to as “dancer rollers.” 
     One end of the support member  38  supporting the movable rollers  34  in the Y direction (width direction) is coupled with one end of a wire  42 . The wire  42  extends upward from the one end of the support member  38  and changes the direction to downward via the outer circumferential surface of each of two support pulleys  44   a  and  44   b . The other end of the wire  42  is wound around a tension pulley  46  coupled to a rotation shaft of a tensile force motor M 3 . The tensile force motor M 3  is fixed to a fixed frame  16  forming the accumulation device  10 . 
     The tensioning unit  30  having the structure described above is configured such that gravity acting on the movable unit  40  in the direction away from the fixed rollers  32  causes predetermined tensile force to be applied to the substrate S. More specifically, in the tensioning unit  30 , downward tensile force F 1  acts on the one end of the wire  42  due to the weight of the movable rollers  34  and the support member  38 . On the other hand, downward tensile force F 2  acts on the other end of the wire  42  by controlling the torque of the tensile force motor M 3  by the controller  90 . The tensile force F 2  is set smaller than the tensile force F 1 . Therefore, during the steady operation in which the substrate S is transported at a predetermined rate, downward load Ft=F 1 −F 2  acts on the movable unit  40 , so that a predetermined tensile force is applied to the substrate S which is continuously transported while running between the fixed rollers  32  and the movable rollers  34 . 
     In the present embodiment, torque control of the tensile force motor M 3  described above enables rapid and accurate adjustment of the load Ft acting on the movable unit  40 . This further facilitates adjustments of desired tensile force when the type of the substrate S (e.g., thickness, materials) is changed. However, the structure in which the predetermined tensile force is applied to the substrate S in the tensioning unit  30  is not limited to the example structure in which a motor for torque control is used. For example, rather than providing the tensile force motor M 3 , the load Ft may be set only by the self-weight of the movable unit  40 , the support member  38  may be weighted so that the load Ft can be adjusted, or a counterweight may be mounted on the other end of the wire  42  to adjust the tensile force F 2 . 
     As illustrated in  FIG. 1 , the tensioning unit  30  includes a height position sensor  39  for detecting the height position of the support member  38  of the movable unit  40 . The height position sensor  39  transmits the detection result, as a signal, to the controller  90 . The controller  90  performs control to maintain a constant height position of the movable unit  40 ; that is, a constant height position of the movable rollers  34 , based on the detection result from the height position sensor  39 , as will be described below. 
     The height position sensor  39  can be formed by an encoder coupled to the support member  38  for detecting the length of a wire  48  which is fed, as illustrated in  FIG. 2 . However, the height position sensor  39  is not limited to this example, and may be formed, for example, of other types of sensors such as an optical sensor including a light-emitting element and a light-receiving element, and a contact sensor which contacts the support member  38  to detect the height position of the movable unit  40 . 
     Referring now to  FIG. 3  and  FIG. 4 , in addition to  FIG. 1 , the accumulation unit  50  of the accumulation device  10  will be described.  FIG. 3  is a side view illustrating the drive mechanism of the accumulation unit  50 .  FIG. 4  is a cross sectional view taken along line C-C in  FIG. 3  with arrow indication. 
     As illustrated in  FIG. 1 , the accumulation unit  50  includes a set of upper rollers (a set of first rollers)  54  including a plurality of rotatable upper rollers (first rollers)  52  spaced from each other and disposed in parallel to each other, and a set of lower rollers (set of second rollers)  58  including a plurality of lower rollers (second rollers)  56  arranged below the set of upper rollers  54  to be movable toward and away from the set of upper rollers  54 . In the present embodiment, the accumulation unit  50  includes eight upper rollers  52  and seven lower rollers  56  disposed below the upper rollers  52  at positions corresponding to the intervals between the upper rollers  52 . The number of upper rollers  52  and the lower rollers  56  can be modified as appropriate based on the length of the substrate to be accumulated in the accumulation device  10  or the transportation rate of the substrate. 
     As illustrated in  FIG. 1  and  FIG. 3 , opposite ends of each upper roller  52  are rotatably supported at ends of arm portions  61  projecting in a comb-like shape in a pair of upper support members  60 . Further, opposite ends of each lower roller  56  are rotatably supported at ends of arm portions  63  projecting in a comb-like shape in a pair of lower support members  62 . In the accumulation unit  50 , the substrate S is transported in the directions of arrows while winding around the upper rollers  52  and the lower rollers  56  alternately.  FIG. 1  shows only one of the pair of upper support members  60  and one of the pair of lower support members  62 . 
     As further illustrated in  FIG. 3 , the accumulation unit  50  includes a drive mechanism  64  which causes the set of upper rollers  54  and the set of lower rollers  58  to perform opening and closing operations to thereby change the distance between the set of upper rollers  54  and the set of lower rollers  58 . The drive mechanism  64  includes an upper ball screw  66 U and a lower ball screw  66 L, an upper gear  68 U and a lower gear  68 L fixed to lower ends of the ball screws  66 U and  66 L, respectively, a pulley  69  coupled to a lower portion of the lower gear  68 L concentrically, and an accumulation motor M 4  for driving and rotating the lower gear  68 L and the pulley  69 . 
     A nut portion  65 U which is integrally formed with the upper support member  60  engages the upper ball screw  66 U. Further, a nut portion  65 L which is integrally formed with the lower support member  62  engages the lower ball screw  66 L. The ball screws  66 U and  66 L are rotatably supported on a fixed frame of the accumulation device  10  which is not shown, in parallel to each other along the vertical direction. While, for ease of understanding,  FIG. 3  (and also  FIG. 4 ) shows the two ball screws  66 U and  66 L such that they are shifted from each other in the X direction, the two ball screws  66 U and  66 L may be disposed such that they are aligned in the Y direction. 
     As illustrated in  FIG. 3  and  FIG. 4 , the pulley  69  coupled to the lower end of the lower ball screw  66 L is preferably a timing pulley, and an endless belt  70  to be wound around this pulley  69  is preferably a timing belt. Use of a timing pulley and a timing belt as described above prevents variations in the amount of rotation of the ball screws  66 U and  66 L caused by slip of the belt, allowing accurate control of the amount of opening and closing operations of the set of upper rollers  54  and the set of lower rollers  58  in the accumulation unit  50 . 
     A drive mechanism having a structure substantially similar to that illustrated in  FIG. 3  except the accumulation motor M 4  is also provided on the upstream ends of the upper support member  60  and the lower support member  62 . The belt  70  is wound around the pulley of the drive mechanism disposed on the upstream ends in the accumulation unit  50 . Thus, driving of the pulley  69  to rotate by the accumulation motor M 4  causes the upper ball screw  66 U and the lower ball screw  66 L to be driven to rotate on each of the opposite ends of the accumulation unit  50  in the X direction. 
     As the accumulation motor M 4 , a servo motor is preferably used, for example. The accumulation motor M 4  is driven to rotate in accordance with instructions from the controller  90 . The accumulation motor M 4  is fixed to the fixed frame of the accumulation device  10  which is not shown. 
     As illustrated in  FIG. 4 , the upper gear  68 U and the lower gear  68 L engage with each other in the drive mechanism  64 . Therefore, driving the lower ball screw  66 L to rotate by the accumulation motor M 4  results in rotation of the upper ball screw  66 U in the reverse direction by the same rotation amount. This causes the sets of lower rollers  58  mounted to the lower ball screw  66 L via the nut portion  65 L to move downward while causing the set of upper rollers  54  mounted to the upper ball screw  66 U via the nut portion  65 U to move upward. In other words, the set of upper rollers  54  and the set of lower rollers  58  move away from each other, causing the accumulation unit  50  to perform the opening operation. Consequently, the distance between the set of upper rollers  54  and the set of lower rollers  58  increases to thereby increase the length of the substrate S to be accumulated in the accumulation unit  50 . 
     On the contrary, driving of the ball screws  66 U and  66 L by the accumulation motor M 4  to rotate in the reverse direction causes the set of lower rollers  58  to move upward and causes the set of upper rollers  54  to move downward. In other words, the set of upper rollers  54  and the set of lower rollers  58  move toward each other, causing the accumulation unit  50  to perform the closing operation. Consequently, the distance between the set of upper rollers  54  and the set of lower rollers  58  decreases to thereby reduce the length of the substrate S to be accumulated in the accumulation unit  50 . 
     The accumulation unit  50  according to the present embodiment is configured such that, with the upper gear  68 U coupled to the upper ball screw  66 U and the lower gear  68 L coupled to the lower ball screw  66 L being engaged with each other, the single accumulation motor M 4  drives the ball screws  66 U and  66 L to rotate. This configuration allows the torque acting on the upper ball screw  66 U for supporting the total weight of the set of upper rollers  54  and the upper support member  60  and the torque acting on the lower baller screw  66 L for supporting the total weight of the set of the lower rollers  58  and the lower support member  62  to work in directions cancelling each other in the engagement portion of each of the gears  68 U and  68 L. Therefore, the two ball screws  66 U and  66 L can be rotated with a light torque, which leads to an advantage that the accumulation motor M 4  which is small and inexpensive can be used. 
       FIG. 5  is a perspective view illustrating a tendency mechanism provided on each roller of the accumulation unit  50 . Further,  FIG. 6  is a graph showing the tendency of the tensile force acting on the substrate S in the accumulation unit  50 . In the accumulation unit  50  according to the present embodiment, the upper rollers  52  and the lower rollers  56  preferably include a tendency mechanism illustrated in  FIG. 5 . In this tendency mechanism, a roller portion  71  of each of the rollers  52  and  56  is rotatably supported, on an inner circumferential surface, by a bearing member  73  fixed to a shaft  72 . A pulley  74  is attached to an end of the shaft  72  protruding beyond the roller portion  71 , and a belt  75  is wound around this pulley  74 . This configuration enables the shaft  72  to rotate at the same rotation rate as that of the roller portion  71  in the same direction by driving the belt  75  to rotate by a motor which is not shown, when the roller portion  71  of each of the rollers  52  and  56  rotates with running of the substrate S. This results in substantial cancellation of mechanical rotational resistance caused by the bearing member  73 , thereby preventing an increase in the tensile force of the substrate S caused by accumulative addition of the mechanical rotational resistances of a plurality of upper rollers  52  and lower rollers  56  in the accumulation unit  50 . 
     More specifically, as illustrated in  FIG. 6 , the tensile force of the substrate S at an entrance (upstream side) of the accumulation unit  50  is constant according to the predetermined tensile force applied by the tensioning unit  30 . When each of the rollers  52  and  56  of the accumulation unit  50  includes no tendency mechanism, cumulative addition of the mechanical rotational resistance of the bearing members of the rollers  52  and  56  leads to a tendency of the tensile force of the substrate S at the exit (downstream side) of the accumulation unit  50  to increase in proportion to the transportation rate of the substrate S, as shown by a dashed and double-dotted line in  FIG. 6 . This tendency becomes particularly noticeable when the transportation rate of the substrate S is high, such as several hundreds of meters per minute. The tendency mechanism mounted in the rollers  52  and  56  according to the present embodiment can suppress the increase in the tensile force of the substrate S caused by the mechanical rotational resistance of the bearing member at the exit of the accumulation unit  50 . Thus, the tendency mechanism, along with the effects obtained by control of the tensioning unit  30  and the accumulation unit  50  as will be described below, can contribute to suppression of fluctuation in the tensile force of the substrate S in the accumulation device  10 . 
     Referring back to  FIG. 1 , the accumulation unit  50  further includes a home position sensor  76  for detecting the height position of the lower support member  62 . The home position sensor  76  has a function to detect whether the lower support member  62  and the set of lower rollers  58  are at a predetermined height position in the steady operation state. For the home position sensor  76 , a sensor, such as a potentiometer and a linear encoder, may be used. The detection result of the home position sensor  76  is transmitted, as a signal S 3 , to the controller  90 . 
     As illustrated in  FIG. 1 , the controller  90  preferably includes a microcomputer including a CPU (Central Processing Unit) for executing control programs and a storage device such as a ROM (Read Only Memory) and a RAM (Random Access Memory) for storing control programs and detection data of each sensor, for example. The controller  90  receives signals from the sensors  7 ,  26 ,  39 ,  76 , and  86 . The controller  90  further transmits signals to each of the motors M 1 , M 2 , M 3 , and M 4  to control the operation of each motor. The controller  90  may further include an operation panel (not shown). The operator can use the operation panel to instruct operation and stop of the system  100 , setting of the substrate transportation rate, and the like. 
     Referring further to  FIG. 7  to  FIG. 10 , control of the accumulation device  10  as configured above will be described.  FIG. 7  is a flowchart showing processing for steady operation control which is executed in the controller  90  illustrated in  FIG. 1 .  FIG. 8  is a flowchart showing processing for accumulation operation control which is executed by the controller  90 .  FIG. 9  is a flowchart showing the processing for accumulation operation control which is executed by the controller  90  continuously from  FIG. 8 . Further,  FIG. 10  illustrates the accumulation operation state in the accumulation device  10 . 
     Referring first to  FIG. 7 , the steady operation control for the accumulation device  10  will be described. In step S 10 , the controller  90  performs control to apply a predetermined torque to the tensile force motor M 3 . This allows the tensioning unit  30  to apply a desired tensile force to the substrate S while the substrate S is continuously transported at a predetermined rate (e.g., several hundreds of meters per minute) by the infeed unit  20  and the outfeed unit  80 . 
     In step S 12 , the controller  90  then places the infeed motor M 1  of the infeed unit  20  and the outfeed motor M 2  of the outfeed unit  80  in synchronism with each other and drives these motors to rotate at a predetermined constant rate. Consequently, the substrate S sent out from the film supply unit  2  in the film processing system  1  and subjected to predetermined processing in the processor  4  is transported at the constant rate via the accumulation device  10  and is wound by the winding unit  5 . 
     Then, in step S 14 , the controller  90  locks the accumulation motor M 4  in the accumulation unit  50 . Specifically, in this state, the set of upper rollers  54  and the set of lower rollers  58  are maintained in a predetermined positional relationship in which the set of upper rollers  54  and the set of lower rollers  58  are close to each other in the accumulation unit  50 . 
     In step S 16 , the controller  90  then determines whether the position of the dancer rollers; that is, the position of the movable rollers  34  of the tensioning unit  30 , is lower than a predetermined height. The determination is performed based on the signal supplied from the height position sensor  39  in the tensioning unit  30 . If an affirmative determination is made (YES in step S 16 ), the outfeed motor M 2  is accelerated in the following step S 18 . As this prevents the opening and closing operation of each set of rollers  54  and  58  in the accumulation unit  50 , the acceleration of the outfeed motor M 2  causes the movable roller  34  in the tensioning unit  30  to move upward. On the other hand, if a negative determination is made in step S 16  described above; that is, if it is determined that the position of the dancer rollers is not lower than the predetermined height, the outfeed motor M 2  is decelerated in step S 20 . 
     In the subsequent step S 22 , the controller  90  determines whether or not there is a stop instruction for the steady operation. The stop instruction for the steady operation is generated by the controller  90  based on a detection signal from the substrate winding amount detection sensor  7  which detects the winding amount of the substrate S by the winding reel  6  reaching the predetermined amount, for example. The stop instruction for the steady operation is also generated when an operation to stop the film processing system  1  itself is performed. 
     If a negative determination is made in step S 22  described above (NO in step S 22 ), processes in steps S 12  to S 22  are repeated. This allows the substrate S to be continuously transported through the accumulation device  10  with the predetermined tensile force applied to the substrate S by the tensioning unit  30  and with the movable rollers  34  being maintained at a constant height. If, on the other hand, it is determined that there is a stop instruction for the steady operation in step S 22  (YES in step S 22 ), the controller  90  terminates the steady operation control. 
     Referring now to  FIG. 8  and  FIG. 9 , the accumulation operation control for the accumulation device  10  will be described. This control is executed when replacing the winding reel automatically or manually based on the detection result from the substrate winding amount detection sensor  7  of the winding unit  5 . 
     As illustrated in  FIG. 8 , in step S 10 , the controller  90  performs control to apply constant torque to the tensile force motor M 3 . This processing is the same as the processing in the steady operation control described above. 
     The controller  90  then causes the infeed motor M 1  to rotate at the constant rate of the steady operation state in step S 23 , while causing the outfeed motor M 2  to decelerate and stop in step S 24 . This causes the substrate S to be continuously fed in but prevents the substrate S from being fed out in the accumulation device  10 . 
     In step S 26 , the controller  90  determines whether or not the position of the dancer rollers; that is, the height position of the movable rollers  34  of the tensioning unit  30 , is lower than the predetermined height. This determination is made based on a signal from the height position sensor  39  of the tensioning unit  30 . If an affirmative determination is made (YES in step S 26 ), in step S 28 , the accumulation motor M 4  is driven in the forward direction to cause the accumulation unit  50  to perform the opening operation. This control causes the set of upper rollers  54  to move upward and the set of lower rollers  58  to move downward in the accumulation unit  50 , as illustrated in  FIG. 10 . As a result, a surplus of the substrate S generated by continuously feeding in the substrate while stopping outfeed of the substrate can be absorbed and accumulated by the opening operation of the accumulation unit  50 . Therefore, the tensioning unit  30  can maintain the movable rollers  34  at a constant height position, to thereby maintain the state in which a predetermined tensile force is applied to the substrate S. 
     In the following step S 32 , the controller  90  determines whether or not there is an accumulation opening operation termination instruction. The accumulation opening operation termination instruction may be generated by the controller  90  when, for example, it is detected based on the signal from the substrate winding amount detection sensor  7  that the winding reel has been replaced in the winding unit  5  to allow resumption of winding of the substrate S, or may be generated by the controller  90  when the operator performs an operation to terminate replacement of the winding reel. 
     If in step S 32  it is not determined that there is an accumulation opening operation termination instruction (NO in step S 32 ), the controller  90  repeats the steps S 23  to S 32 . During this period, if the position of the dancer rollers is not determined to be lower than the predetermined height in step S 26  (NO in step S 26 ), in step S 30 , the accumulation motor M 4  is driven in the reverse direction to cause the accumulation unit  50  to perform the closing operation. However, because the opening operation is performed such that the predetermined maximum position is reached in the accumulation unit  50  while the accumulation operation; that is, the substrate accumulation operation is continued, the processing in step S 30  described above is rarely performed. 
     If it is determined in step S 32  that there is an accumulation opening operation termination instruction (YES in step S 32 ), the controller  90  accelerates the outfeed motor M 2  to achieve the rate which is higher than the steady operation rate (e.g., 1.2 times the steady operation rate) in step S 34 , as illustrated in  FIG. 9 . 
     In the following step S 36 , the controller  90  determines whether or not the position of the dancer rollers is lower than the predetermined height. This determination is similar to those in steps S 16  and S 26  described above. If an affirmative determination is made (YES in step S 36 ), in step S 38 , the accumulation motor M 4  is driven in the forward direction to cause the accumulation unit  50  to perform the opening operation. In this case, however, because the outfeed rate of the substrate S in the outfeed unit  80  is set to be higher than the infeed rate in the infeed unit  20 , in most cases, the position of the dancer rollers is not lower than the predetermined height; that is, higher than the predetermined height in the determination in step S 36 . Therefore, in this case, a negative determination is made in step S 36 , and, in the following step S 40 , the accumulation motor M 4  is driven in the reverse direction to cause the accumulation unit  50  to perform the closing operation. Specifically, the set of upper rollers  54  is moved downward and the set of lower rollers  58  is moved upward, so that the upper and lower rollers are moved toward each other. 
     In step S 42 , the controller  90  determines whether the accumulation unit  50  reaches the steady operation position. This determination is made based on a detection signal from the home position sensor  76  that detects the height position of the lower support member  62  for supporting the set of lower rollers  58 . If a negative determination is made (NO in step S 42 ), the steps S 36  to S 42  are repeated. On the other hand, if it is determined that the accumulation unit  50  has returned to the steady operation position (YES in step S 42 ), in step S 44 , the outfeed motor M 2  is decelerated to the steady operation rate. More specifically, in this state, the infeed motor M 1  and the outfeed motor M 2  are driven at the same rate, and the operation state is shifted to the steady operation state in which the substrate S is continuously transported at the predetermined rate. 
     As described above, because the accumulation device  10  according to the present embodiment includes the tensioning unit  30  for applying tensile force to the substrate S and the accumulation unit for accumulating a surplus of the substrate, generated by continuously feeding in the substrate while stopping feeding out the substrate, as separate units, the tensioning unit can apply desired tensile force to the substrate S while applying relatively small load Ft to the substrate S. Further, in order to maintain the movable rollers  34  at the constant height position with respect to the fixed rollers  32  in the tensioning unit  30 , the controller  90  controls the substrate outfeed rate of the outfeed unit  80  during the steady operation, and controls the opening and closing operation of the accumulation unit  50  during the accumulation operation. This control can reduce the fluctuation in the tensile force of the substrate S caused by movement of the movable rollers  34  with respect to the fixed rollers  32  in the tensioning unit  30 . Therefore, even when the operation state switches between the steady operation state in which a long belt-like substrate S is continuously transported at the predetermined rate and the accumulation operation state in which the substrate S which is fed in is accumulated while outfeed of the substrate S is being stopped, the fluctuation in the tensile force acting on the substrate S can be reduced. This can prevent meandering and looseness of the substrate S caused by the fluctuation in the tensile force, thereby reducing generation of resulting wrinkles and breakages of the substrate S. 
     Referring further to  FIG. 11  to  FIG. 13 , an example in which the accumulation device  10  includes the lower rollers  56  having an independent suspension structure will be described.  FIG. 11  illustrates an accumulation unit  50   a  in which the lower rollers  56  of the accumulation unit  50   a  have an independent suspension structure.  FIG. 12  is a cross sectional view taken along line D-D in  FIG. 11 . In the following description, elements which are the same as those of the accumulation device  10  described above are designated by the same reference numerals and their explanations will not be repeated. 
     As illustrated in  FIG. 11 , each of a pair of lower support members  62   a  in the accumulation unit  50   a  includes comb-like arm portions  63  which rotatably support the respective lower rollers  56  and are formed projecting downward (−Z direction). Each of the lower rollers  56  is coupled to the tip end portion of the respective arm portion  63  via an elastic member  87 . The drive mechanism  64  for lifting and lowering the pair of lower support members  62   a  is similar to that described with reference to  FIGS. 3 and 4 . 
     As illustrated in  FIG. 12 , a coupling member  89  is disposed on the lower end of each arm portion  63  with a bolt fastener, for example, in the pair of lower support members  62   a . The coupling member  89  includes two through holes  89   a  spaced in the Y direction. The coupling member  89  further includes, on a lower surface, two recess portions  89   b  each housing an end of a coil spring which will be described below. 
     A movable member  88  is mounted on the coupling member  89  disposed between the arm portions  63  of the pair of lower support members  62   a . A plurality of shaft members  94  are provided vertically on a top surface of the movable member  88  such that the shaft members  94  are inserted through the corresponding through holes  89   a  of the coupling member  89 . A stopper  95  having a larger diameter than the through hole  89   a  is disposed on the upper end of the shaft member  94 . This structure can support the movable member  88  in a manner movable in the vertical direction with respect to the coupling member  89  (that is, the pair of lower support members  62   a ). The stopper  95  regulates the movable length of the movable member  88  in the vertical direction. 
     The movable member  88  includes two side wall portions  92  suspended at opposite ends thereof in the Y direction. The lower roller  56  is rotatably supported between these side wall portions  92 . More specifically, the lower roller  56  includes a shaft  72  serving as a rotation center axis, and a cylindrical roller portion  71  rotatably supported by two bearing members  73  fixed to opposite ends of the shaft  72 , and the shaft  72  is fixed to the two side wall portions  92  of the movable member  88  at the respective ends. This structure allows the lower roller  56  to be rotatably supported by the movable member  88 . 
     The movable member  88  includes, on a top surface thereof, two recess portions  93  formed to oppose the recess portions  89   b  of the coupling member  89 , respectively. A coil spring forming the elastic member  87  is disposed between the coupling member  89  and the movable member  88 . Each of the two coil springs forming the elastic member  87  is positioned with the respective ends being fitted into the recess portions  89   b  and  93  of the coupling member  89  and the movable member  88 , respectively. 
       FIG. 12  illustrates the steady operation state in which the substrate S is continuously transported at a constant rate in the accumulation unit  50   a . During the steady operation state, predetermined tensile force acts on the substrate S being transported, so that the movable member  88  supporting the lower roller  56  is lifted against the urging force of the elastic member  87 . Specifically, the coil spring which is the elastic member  87  is in a compressed state and urges the lower roller  56  downward. 
     While a coil spring is used as the elastic member  87  in this embodiment, the elastic member is not limited to this example, and any other elastic member that generates downward urging force with respect to the lower rollers  56 , such as a flat spring or an air spring, may be used. 
     Further, while in this embodiment, the lower roller  56  is urged by the elastic member  87 , this is not limited to this example, and the lower roller  56  may be urged with respect to the substrate S only by the self-weight of the lower rollers  56  and the movable member  88 . In this case, the elastic member  87  and the recess portions  89   b  and  93  can be omitted. 
     Referring to  FIG. 13  in addition to  FIG. 11 , the operation of the accumulation unit  50   a  will be described.  FIG. 13  illustrates a state in which the accumulation unit  50   a  illustrated in  FIG. 11  performs the accumulation operation. 
     As illustrated in  FIG. 11 , when the accumulation unit  50   a  is in the steady operation state, the infeed unit  20  and the outfeed unit  80  are driven at the same rate, so that the substrate S is transported at a constant rate while the set of lower rollers  58  including a plurality of lower rollers  56  is maintained at a certain height position in the accumulation unit  50   a . At this time, the tensile force acting on the substrate S places each of the lower rollers  56  in a lifted state against the urging force of the elastic member  87  as described above. 
     When the operation of a downstream device disposed on the downstream in the substrate transporting direction of the accumulation device  10  is interrupted, as illustrated in  FIG. 10 , an instruction from the controller  90  causes the outfeed unit  80  to reduce the rotation rate and stop and simultaneously causes the infeed unit  20  to continuously feed in the substrate S at the same rate as that in the steady operation. Thus, the difference between the outfeed rate of the substrate S by the outfeed unit  80  and the infeed rate by the infeed unit  20  generates a surplus of the substrate S. To absorb the surplus of the substrate S, the accumulation unit  50   a  performs the accumulation operation. 
     More specifically, when the outfeed unit  80  starts decelerating, in order to accumulate the resulting surplus of the substrate S, the set of upper rollers  54  moves upward and the set of lower rollers  58  moves downward in the direction of arrow G as illustrated in  FIG. 13 . This results in an increase in the distance between the set of upper rollers  54  and the set of lower rollers  58 , so that the surplus of the substrate S is absorbed and accumulated in the accumulation unit  50   a . At this time, the set of lower rollers  58  can be lowered to a predetermined height position which is separated from the set of upper rollers  54  by the maximum distance, and the downward urging force by the elastic member  87  continuously acts on the lower rollers  56  until the lower rollers  56  reach the predetermined height position and after the lower rollers  56  have reached the predetermined height position. Unless the tensile force acting on the substrate S fluctuates, the compression amount of the elastic member  87  does not change and therefore the urging force by the elastic member  87  is constant. 
     During this accumulation operation, no problems would arise when the operation to move each lower roller  56  downward by the drive mechanism  64  (see  FIG. 3 ) is performed such that no fluctuation in the tensile force is caused in the substrate S. However, when the responsiveness of the accumulation operation is slightly slow, as described above with reference to  FIG. 11 , the substrate S may be loosened and float off momentarily with respect to one or more lower rollers  56   a  located upstream in the substrate transporting direction (the right side in  FIG. 11 ). This state is illustrated with dashed line St in  FIG. 11 . Such a phenomenon in which the substrate S is loosened and floats off becomes more noticeable when the transportation rate of the substrate S is as high such as several hundreds of meters per minute. When such looseness is generated even momentarily, the substrate S may meander, leading to formation of wrinkles in the substrate S to be wound. 
     To the contrary, the accumulation unit  50   a  according to the embodiment adopts an “independent suspension system” in which each lower roller  56  is supported while being urged downward independently by the elastic member  87 . Therefore, even when fluctuation in the tensile force occurs in the substrate S during the accumulation operation as described above, and the fluctuation in the tensile force causes the substrate S to float off from the lower roller  56 , this structure enables each lower roller  56 , particularly one or more lower rollers  56   a  located upstream in the transporting direction of the substrate, to follow the movement of the substrate S and move downward by its self-weight and the urging force of the elastic member  87 . This allows the lower rollers  56  to remain in contact with the substrate S, to thereby prevent formation of an air layer between the substrate S and the lower rollers  56  and to effectively reduce occurrence of meandering of the substrate S and the resulting wrinkles of the substrate S. 
     Further, when the substrate S is transported at a constant rate during the steady operation, a phenomenon may occur in which air is accumulated within the cylindrical substrate S to inflate the substrate S into a balloon shape at a location immediately before the lower rollers  56 , as illustrated with dashed line  101  in  FIG. 14 . As the accumulation unit  50   a  according to the embodiment includes each lower roller  56  in an independent suspension system as described above, an increase in the pressure of the air accumulated in the cylindrical substrate S lifts the lower rollers  56  against the urging force of the elastic member  87 , allowing the air within the substrate S to escape downward. Consequently, transportation troubles for the substrate S caused by accumulation of the air can be reduced. 
     The accumulation device according to the present invention is not limited to the embodiment and the modification example thereof described above. Various modifications and improvements may be made within the scope of matters described in the scope of the claims and within the equivalent scopes. 
     For example, while in the above example, all the lower rollers  56  are supported by an independent suspension system, the present invention is not limited to this example and may have a structure in which only a part of the lower rollers  56  (especially one or more lower rollers  56   a  located upstream in the substrate transporting direction) are supported by an independent suspension system. Alternatively, the upper rollers  52 , in place of or in addition to the lower rollers  56 , may be supported by the independent suspension system using a structure similar to that described above. 
     While in the above examples, during the accumulation operation of the accumulation units  50  and  50   a , the set of upper rollers  54  is lifted while the set of lower rollers  58  is lowered to thereby increase the lengths of the substrate which can be accumulated, the present invention is not limited to this structure. For example, the set of upper rollers  54  may be fixedly disposed while only the set of lower rollers  58  is allowed to moved, or vice versa. 
     While in the above examples, the accumulation device  10  including the accumulation unit  50  or  50   a  having the set of upper rollers  54  and the set of lower rollers  58  that are moved upward and downward has been described, the present invention is not limited to this structure. The present invention may be applied, for example, to an accumulation device including a set of first rollers composed of a plurality of rotatable first rollers and a set of second rollers composed of a plurality of rotatable second rollers that are movable toward and away from the set of first rollers, in which the second set of rollers is moved relative to the first set of rollers in the horizontal direction or in the direction crossing the horizontal direction to thereby change the distance between the first and second sets of rollers. 
     Further, while in the above examples, the outfeed rate of the substrate is changed to perform control to maintain the movable roller  34  in the tensioning unit  30  at a constant height without performing the opening or closing operations of the accumulation unit  50  during the steady operation of the accumulation device  10 , the present invention is not limited to these examples. For example, control may be performed to maintain the constant position of the movable rollers  34  of the tensioning unit  30  while performing the opening and closing operations of the accumulation unit  50  similar to the control in the accumulation operation. 
     Also, while in the above examples, the film processing system  1  including the accumulation device  10  between the processor  4  and the winding unit  5  has been described, the present invention is not limited to this structure, and may be applied to the label fitting system as described in Patent Documents 1 and 2. In this case, the accumulation device is disposed between the substrate feeding device, which is an upstream device, and the label fitting device, which is a downstream device. During the steady operation in which the label substrate is sent out from the substrate feeding device at a constant rate, the accumulation device is in an open state to accumulate the label substrate, and during temporary interruption of feeding of the label substrate associated with replacement of the substrate reel of the substrate feeding device, the accumulation device is closed and simultaneously outfeed of the label substrate which is accumulated is continued, thereby enabling continuous operation of the label fitting device. Further, in this case, it is preferable to perform control to maintain the constant height position of the movable rollers  34  of the accumulation unit  30  by changing the infeed rate of the infeed unit  20  for feeding the substrate fed from the substrate feeding device into the accumulation device during the steady operation of the accumulation device. 
     REFERENCE SIGNS LIST 
     
         
           1  film processing system 
           2  film supply unit 
           3  supply reel 
           4  processor 
           5  winding unit 
           6  winding reel 
           7  substrate winding amount detection sensor 
           10 ,  100  accumulation device 
           12 ,  14  fixed frame 
           20  infeed unit 
           22 ,  82  drive roller 
           24 ,  84  slave roller 
           26 ,  86  rotation rate detection sensor 
           30  tensioning unit 
           32  fixed roller 
           34  movable roller 
           36  support roller 
           38  support member 
           39  height position sensor 
           40  movable unit 
           42 ,  48  wire 
           44   a ,  44   b  support pulley 
           46  tension pulley 
           50 ,  50   a  accumulation unit 
           52  upper roller 
           54  set of upper rollers 
           56  lower roller 
           58  set of lower rollers 
           60  upper support member 
           61 ,  63  arm portion 
           62 ,  62   a  lower support member 
           64  drive mechanism 
           65 L,  65 U nut portion 
           68 L lower gear 
           68 U upper gear 
           69 ,  74  pulley 
           70 ,  75  belt 
           71  roller portion 
           72  shaft 
           73  bearing member 
           76  home position sensor 
           80  outfeed unit 
           86  rotation rate detection sensor 
           87  elastic member 
           88  movable member 
           89  coupling member 
           89   a  through hole 
           89   b ,  93  recess portion 
           90  controller 
           92  side wall portion 
           94  shaft member 
           95  stopper 
         Ft load 
         M 1  infeed motor 
         M 2  outfeed motor 
         M 3  tensile force motor 
         M 4  accumulator 
         S substrate 
         S 1 , S 2 , S 3  signal