Patent Publication Number: US-2020282683-A1

Title: Sheet folding device and box-making machine

Description:
RELATED APPLICATIONS 
     The present application is a National Phase of International Application Number PCT/JP2017/037214 filed Oct. 13, 2017 and claims priority to Japanese Application Number 2016-206278 filed Oct. 20, 2016. 
    
    
     TECHNICAL FIELD 
     The present invention relates to a sheet folding device which forms a flat corrugated box by folding a corrugated fiberboard while transferring the corrugated fiberboard in a process of manufacturing a corrugated box and a box making machine including the sheet folding device. 
     BACKGROUND ART 
     A general box making machine manufactures a box body (corrugated box) by processing a sheet material (for example, a corrugated fiberboard), and includes a sheet feeding section, a printing section, a slotter creaser section, a die cutting section, a folding section (folder gluer), and a counter-ejector section. In the sheet feeding section, the corrugated fiberboards stacked on a table are fed to the printing section one by one at a constant speed. The printing section includes a printing unit and performs printing on the corrugated fiberboard. In the slotter creaser section, creasing lines which become folding lines are formed on the printed corrugated fiberboard, and processing of grooves becoming flaps or gluing margin strips for joining is performed. In the die cutting section, punching such as hand hole is performed on the corrugated fiberboard on which the creasing lines, the grooves, and gluing margin strips are formed. In the folding section, glue is applied to the gluing margin strip and the corrugated fiberboard on which the creasing lines, the grooves, the gluing margin strips, and the hand holes are formed is folded along the creasing lines while the corrugated fiberboard moves, and the gluing margin strips are joined to each other to manufacture a flat corrugated box. In addition, in the counter-ejector section, the corrugated boxes in which corrugated fiberboards are folded and glued are stacked, the stacked corrugated boxes are sorted by a predetermined number of batches, and the sorted corrugated boxes are discharged. 
     In the above-described folding section, folding rails and guide plates are disposed in series along a transfer direction on both sides of the corrugated fiberboard in the transfer direction, several gauge rollers are disposed outside the folding rails and guide plates along the transfer direction, and a folding belt and a folding bar are disposed. Accordingly, the corrugated fiberboard is transferred while a position in a width direction is restricted by the folding rails and is pressed by the folding belt and the folding bar, and thus, both end portions in the width direction are bent downward. In addition, when both end portions in the width direction of the corrugated fiberboard are bent downward, bending portion sides of both ends in the width direction of the corrugated fiberboard are held by the several gauge rollers, both bent end portions are closely adhered to the inside, and a flat corrugated box is formed. 
     The sheet folding device of the related art is disclosed in PTL 1 and PTL 2 below. 
     CITATION LIST 
     Patent Literature 
     [PTL 1] Japanese Patent No. 4701062 
     [PTL 2] Japanese Patent No. 4609809 
     SUMMARY OF INVENTION 
     Technical Problem 
     In the above-described sheet folding device, at an initial stage where both end portions in the width direction of the corrugated fiberboard are bent downward, an inner side of the corrugated fiberboard is restricted by the folding rails and an outer side thereof is restricted by the gauge rollers. The corrugated fiberboard has different rigidities according to a thickness, a nature, a shape, or the like of a liner or a core paper. If the corrugated fiberboard has a high rigidity, when the corrugated fiberboard is clamped by the folding rails and the gauge rollers, the corrugated fiberboard is bent at the position of the creasing lines which are formed in advance. Meanwhile, if the corrugated fiberboard has a low rigidity, when the corrugated fiberboard is clamped by the folding rails and the gauge rollers, the corrugated fiberboard may be bent inside the creasing lines, that is, on a center side in the width direction of the corrugated fiberboard. In this case, an adjustment for moving the folding rail and the gauge roller outward in the width direction is performed in a state where a gap between the folding rail and the gauge roller is maintained. 
     Meanwhile, if the folding rails and the gauge rollers are moved outward in the width direction, in the sheet folding device of PTL 1, a gap between the guide plate and the gauge roller is widened on the downstream side of a first correction roller group. In addition, in the corrugated fiberboard, if a folding process progresses, the bending portion tends to be slightly inward. Accordingly, if a position of the gauge roller is moved outward, a gap between the guide plate and the folding portion increases, and thus, an error occurs at a bending position of the corrugated fiberboard. 
     The present invention is made in order to solve the above-described problems, and an object thereof is to provide a sheet folding device and a box making machine capable of improving bending accuracy of the corrugated fiberboard. 
     Solution to Problem 
     In order to achieve the above-described object, according to an aspect of the present invention, there is provided a sheet folding device which bends and folds both end portions in a width direction of a transferred corrugated fiberboard, including: folding rails which are disposed along a transfer direction on both sides in the transfer direction of the corrugated fiberboard; guide plates which are disposed on downstream sides of the folding rails along the transfer direction on both sides in the transfer direction of the corrugated fiberboard; a gauge roller group including several gauge rollers which are disposed outside the folding rails and the guide plates in a width direction of the corrugated fiberboard, along the transfer direction of the corrugated fiberboard; a folding rail adjustment device which adjusts positions of the folding rails in the width direction of the corrugated fiberboard; and a gauge roller adjustment device which adjusts a position of at least the gauge roller of the gauge roller group, which is disposed to face the folding rail, in the width direction of the corrugated fiberboard. 
     Accordingly, when the position of the folding rail in the width direction of the corrugated fiberboard is adjusted by the folding rail adjustment device, the position in the width direction of the corrugated fiberboard of at least the gauge roller of the gauge roller group facing the folding rail is adjusted by the gauge roller adjustment device. Therefore, even when positions of the folding rail and the gauge roller facing each other or a gap therebetween is adjusted according to a material or the like of the corrugated fiberboard, a gap between the guide plate and the gauge roller is maintained at an appropriate gap, the corrugated fiberboard can be bent at an appropriate position, and it is possible to improve bending accuracy of the corrugated fiberboard. 
     In the sheet folding device of the present invention, the gauge roller adjustment device moves an upstream side of the gauge roller group close to or away from the folding rail with a downstream side of the gauge roller group in the transfer direction of the corrugated fiberboard as a supporting point. 
     Accordingly, when the position of the folding rail in the width direction is adjusted, the gauge roller group rotates with the downstream side as the supporting point, the position of the gauge roller on the upstream side in the width direction is adjusted, the position of the gauge roller facing the folding rail can be appropriately adjusted, and it is possible to bend the corrugated fiberboard at an appropriate position without largely changing the position of the gauge roller facing the guide plate. 
     In the sheet folding device of the present invention, the gauge roller adjustment device moves the gauge roller of the gauge roller group disposed to face the folding rail close to or away from the folding rail. 
     Accordingly, when the position of the folding rail in the width direction is adjusted, only the gauge roller disposed to face the folding rail moves and the position thereof in the width direction is adjusted, the position of the gauge roller facing the folding rail can be appropriately adjusted, and it is possible to bend the corrugated fiberboard at an appropriate position without changing the position of the gauge roller facing the guide plate. 
     In the sheet folding device of the present invention, the folding rail includes a first folding rail and a second folding rail which are disposed in series in the transfer direction of the corrugated fiberboard and have end portions rotatably connected to each other, and the folding rail adjustment device moves the first folding rail and the second folding rail in parallel in the width direction of the corrugated fiberboard and changes an angle of the second folding rail by moving the first folding rail in parallel in the width direction of the corrugated fiberboard. 
     Accordingly, the first folding rail and the second folding rail move in parallel in the width direction, the first folding rail moves in parallel in the width direction so as to change the angle of the second folding rail, and it is possible to easily adjust the position of the gauge roller facing the second folding rail. 
     In the sheet folding device of the present invention, the gauge roller group includes a first gauge roller group and a second gauge roller group which are disposed in series in the transfer direction of the corrugated fiberboard, and the gauge roller adjustment device moves the first gauge roller group in parallel in the width direction of the corrugated fiberboard and changes angles of the first gauge roller group and the second gauge roller group independently. 
     Accordingly, the angle of the first gauge roller group is changed, and thus, it is possible to easily adjust the position of the gauge roller facing the second folding rail. 
     The sheet folding device of the present invention further includes a control device which controls the folding rail adjustment device and the gauge roller adjustment device, in which the control device controls the gauge roller adjustment device such that a gap between the folding rail and the gauge roller when the folding rail is moved by the folding rail adjustment device falls within a predetermined gap region which is set in advance. 
     Accordingly, the position of the folding rail, the position of the gauge roller, and the gap between the folding rail and the gauge roller can be easily adjusted to appropriate positions or an appropriate gap, and thus, workability can be improved. 
     The sheet folding device of the present invention further includes a guide measurement sensor which measures a position of the folding rail, a roller measurement sensor which measures a position of the gauge roller group, and a control device which controls the folding rail adjustment device and the gauge roller adjustment device based on a measurement result of the guide measurement sensor and a measurement result of the roller measurement sensor. 
     Accordingly, the position of the folding rail and the position of the gauge roller group are measured, and the folding rail adjustment device and the gauge roller adjustment device are controlled based on the measurement result. Therefore, it is possible to accurately adjust the position of the folding rail, the position of the gauge roller, and the gap between the folding rail and the gauge roller, and it is possible to improve quality of a product. 
     In the sheet folding device of the present invention, a recessed portion holding a bending portion of the corrugated fiberboard is provided in each of the several gauge rollers, and a holding belt is wound around a bottom surface portion of the recessed portion of each of the several gauge rollers. 
     Accordingly, the corrugated fiberboard is transferred while the bending portion is continuously supported by the holding belt provided in the recessed portion of each gauge roller, the corrugated fiberboard does not fall between the respective gauge rollers, the posture of the corrugated fiberboard does not deteriorate, and the corrugated fiberboard can be stably transferred. 
     The sheet folding device of the present invention further includes a drive device which drives the gauge roller. 
     Accordingly, if the one gauge roller is driven by the drive device, the drive force is transmitted to all the gauge rollers via the holding belt, all the gauge rollers can be synchronously rotated, a drive system of the gauge roller is simplified, and a cost can be reduced. 
     In addition, according to another aspect of the present invention, there is provided a box making machine including: a sheet feeding section which supplies a corrugated fiberboard; a printing section which performs printing on the corrugated fiberboard; a slotter creaser section which performs creasing line processing and slicing on the printed corrugated fiberboard; a folding section which includes the sheet folding device; and a counter-ejector section which stacks flat corrugated boxes while counting the flat corrugated boxes and thereafter, discharges the flat corrugated boxes every predetermined number. 
     Accordingly, the printing is performed on the corrugated fiberboard from the sheet feeding section in the printing section, the creasing line processing and the slicing are performed in the slotter creaser section, the corrugated fiberboard is folded in the folding section such that the end portions are joined to each other so as to form the box body, and the box bodies are stacked while being counted in the counter-ejector section. In this case, in the sheet folding device, when the position of the folding rail in the width direction of the corrugated fiberboard is adjusted by the folding rail adjustment device, the position in the width direction of the corrugated fiberboard of at least the gauge roller of the gauge roller group facing the folding rail is adjusted by the gauge roller adjustment device. Accordingly, the positions of the folding rail and the gauge roller, the gap therebetween, or the gap between the guide plate and the gauge roller can be appropriately adjusted according to a material or the like of the corrugated fiberboard, it is possible to improve bending accuracy of the corrugated fiberboard, and it possible to improve the quality of the product. 
     Advantageous Effects of Invention 
     According to the sheet folding device and the box making machine of the present invention, the folding rail adjustment device which adjusts the position of the folding rail in the width direction and the gauge roller adjustment device which adjusts the position of the gauge roller facing the folding rail in the width direction are provided, and thus, it is possible to bend the corrugated fiberboard at an appropriate position, and it is possible to improve the bending accuracy of the corrugated fiberboard. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1  is a schematic configuration view showing a box making machine of the present embodiment. 
         FIG. 2  is a schematic plan view showing a sheet folding device of the present embodiment. 
         FIG. 3  is a schematic side view showing the sheet folding device. 
         FIG. 4  is a sectional view taken along line Iv-Iv of  FIG. 2 . 
         FIG. 5  is a schematic view showing a folding rail position adjustment device. 
         FIG. 6  is an explanatory view showing a position adjustment method of folding rails and gauge rollers. 
         FIG. 7A  is a schematic view showing a bending state of a corrugated fiberboard of the related art. 
         FIG. 7B  is a schematic view showing the bending state of the corrugated fiberboard of the related art. 
         FIG. 8  is a schematic view showing a bending state of a corrugated fiberboard of the present embodiment. 
         FIG. 9  is a schematic view showing a first modification example of the sheet folding device of the present embodiment. 
         FIG. 10  is a schematic view showing a second modification example of the sheet folding device of the present embodiment. 
         FIG. 11  is a schematic view showing a third modification example of the sheet folding device of the present embodiment. 
         FIG. 12  is a sectional view of a gauge roller. 
     
    
    
     DESCRIPTION OF EMBODIMENTS 
     Hereinafter, preferred embodiments of a sheet folding device and a box making machine according to the present invention will be described in detail with reference to the accompanying drawings. In addition, the present invention is not limited by the embodiment, and in a case where several embodiments are provided, the present invention includes those which are obtained by combining the embodiments. 
       FIG. 1  is a schematic configuration view showing a box making machine of the present embodiment. 
     In the present embodiment, as shown in  FIG. 1 , a box making machine  10  manufactures a corrugated box (box body) B by processing a corrugated fiberboard S. The box making machine  10  includes a sheet feeding section  11 , a printing section  21 , a slotter creaser section  31 , a die cutting section  41 , a folding section  61 , a counter-ejector section  71  which are linearly disposed in a transfer direction D in which the corrugated fiberboard S and the corrugated box B are transferred. 
     In the sheet feeding section  11 , the corrugated fiberboards S are fed to the printing section  21  one by one at a constant speed. The sheet feeding section  11  includes a table  12 , a front stopper  13 , supply rollers  14 , a suction unit  15 , and a feed roll  16 . Several corrugated fiberboards S are placed on the table  12  so as to be stacked, and the table  12  is supported so as to be lifted and lowered. The front stopper  13  can position the front end position of each of the corrugated fiberboards S stacked on the table  12 , and a gap which allows one corrugated fiberboard S to pass through a portion between a lower end portion of the front stopper  13  and the table  12  is secured. Several supply rollers  14  are disposed corresponding to the table  12  in the transfer direction D of the corrugated fiberboard S. When the table  12  is lowered, the corrugated fiberboard S located at the lowermost position of several stacked corrugated fiberboards S can be fed forward by the supply rollers  14 . The stacked corrugated fiberboards S are suctioned downward, that is, toward the table  12  side or the supply roller  14  side by the suction unit  15 . The feed roll  16  can supply the corrugated fiberboard S fed by the supply rollers  14  to the printing section  21 . 
     The printing section  21  performs multi-color printing (in the first embodiment, four-color printing) on a surface of the corrugated fiberboard S. In the printing section  21 , four printing units  21 A,  21 B,  21 C, and  21 D are disposed in series, and printing can be performed on the surface of the corrugated fiberboard S using four ink colors. The printing units  21 A,  21 B,  21 C, and  21 D are approximately similarly configured to each other, and each of the printing units  21 A,  21 B,  21 C, and  21 D includes a printing cylinder  22 , an ink supply roll (anilox roll)  23 , an ink chamber  24 , and a receiving roll  25 . A printing die  26  is mounted on an outer peripheral portion of the printing cylinder  22 , and the printing cylinder  22  is rotatably provided. The ink supply roll  23  is disposed so as to contact against the printing die  26  in the vicinity of the printing cylinder  22 , and is rotatably provided. The ink chamber  24  stores ink and is provided in the vicinity of the ink supply roll  23 . The corrugated fiberboard S is interposed between the receiving roll  25  and the printing cylinder  22 , the receiving roll  25  transfers the corrugated fiberboard S while applying a predetermined printing pressure to the corrugated fiberboard S, and the receiving roll  25  is rotatably provided so as to face the lower portion of the printing cylinder  22 . In addition, although not shown, a pair of upper and lower feed rolls is provided in front of and behind each of the printing units  21 A,  21 B,  21 C, and  21 D. 
     In the slotter creaser section  31 , creasing line processing, cutting, slicing, and gluing margin strip processing are performed on the corrugated fiberboard S by the slotter device. The slotter creaser section  31  includes first creasing line rolls  32 , second creasing line rolls  33 , first slotter heads  34 , second slotter heads  35 , and slitter heads  36 . The first creasing line rolls  32  and the second creasing line rolls  33  perform the creasing line processing on a rear surface (lower surface) of the corrugated fiberboard S. The first slotter head  34  and the second slotter heads  35  perform the slicing on the corrugated fiberboard S at a predetermined position and performs the gluing margin strip processing on the corrugated fiberboard S. The slitter heads  36  are provided to be adjacent to the second slotter heads  35  and cut an end portion in a width direction of the corrugated fiberboard S. 
     In the die cutting section  41 , drilling for forming a hand hole is performed on the corrugated fiberboard S. The die cutting section  41  includes a pair of upper and lower feeding pieces  42 , an anvil cylinder  43 , and a knife cylinder  44 . The feeding pieces  42  are rotatably provided such that the corrugated fiberboard S is transferred in a state where the corrugated fiberboard S is interposed between the upper portion and the lower portion. Each of the anvil cylinder  43  and the knife cylinder  44  is circularly formed, and the anvil cylinder  43  and the knife cylinder  44  are rotatable in synchronization with each other by a drive device (not shown). A head and a die are formed at predetermined positions of an outer peripheral portion of the knife cylinder  44  while an anvil is formed on an outer peripheral portion of the anvil cylinder  43 . 
     In the folding section  61 , the corrugated fiberboard S is folded while being moved in the transfer direction D, and both end portions in the width direction of the corrugated fiberboard S are joined to each other so as to form a flat corrugated box B. The folding section  61  includes an upper transfer belt  62 , lower transfer belts  63  and  64 , and a sheet folding device (folder gluer)  65 . The upper transfer belt  62  and the lower transfer belts  63  and  64  transfer the corrugated fiberboard S and the corrugated box B in a state where the corrugated fiberboard S and the corrugated box B are interposed between the upper portion and the lower portion. Although the sheet folding device  65  will be described later, the sheet folding device  65  folds each end portion in the width direction of the corrugated fiberboard S while bending the end portion downward. In addition, the folding section  61  includes a gluing device  66 . The gluing device  66  includes a glue gun, glue is ejected at a predetermined timing by the glue gun, and gluing can be applied to a predetermined position of the corrugated fiberboard S. 
     In the counter-ejector section  71 , after the corrugated boxes B are stacked while being counted, the corrugated boxes B are sorted by a predetermined number of batches, and thereafter, the sorted corrugated boxes B are discharged. The counter-ejector section  71  includes a hopper device  72 . The hopper device  72  includes an elevator  73  on which corrugated boxes B are stacked and which can be lifted and lowered, and a front stopper and an angle arrangement plate are provided in the elevator  73 . In addition, an ejection conveyor  74  is provided below the hopper device  72 . 
     Here, in the box making machine  10  of the above-described embodiment, an operation for manufacturing the corrugated box B from the corrugated fiberboard S is described. In the box making machine  10  of the present embodiment, after printing, creasing line processing, processing of grooves and gluing margin strips, and punching are performed on the corrugated fiberboard S, the corrugated fiberboard S is folded so as to manufacture the corrugated box B. 
     The corrugated fiberboard S is formed by gluing a medium forming a waveform between a bottom liner and a top liner. As shown in  FIG. 2 , in the corrugated fiberboard S, two folding lines  301  and  302  are formed in a pre-process of the box making machine  10 . The folding lines  301  and  302  are used for folding a flap when the corrugated box B manufactured by the box making machine  10  is assembled later. As shown in  FIG. 1 , the corrugated fiberboards S are stacked on the table  12  of the sheet feeding section  11 . 
     In the sheet feeding section  11 , first, the several corrugated fiberboards S stacked on the table  12  are positioned by the front stopper  13 , and thereafter, the table  12  is lowered, and the corrugated fiberboard S positioned at the lowermost position is fed by several supply rollers  14 . Accordingly, the corrugated fiberboard S is supplied to the printing section  21  at a predetermined constant speed by the pair of feed rolls  16 . 
     In the printing section  21 , ink is supplied from the ink chamber  24  to the surface of the ink supply roll  23  in each of the printing units  21 A,  21 B,  21 C, and  21 D, and if the printing cylinder  22  and the ink supply roll  23  rotate, the ink on the surface of the ink supply roll  23  is transferred to the printing die  26 . If the corrugated fiberboard S is transferred to a portion between the printing cylinder  22  and the receiving roll  25 , the corrugated fiberboard S is interposed between the printing die  26  and the receiving roll  25 , and a printing pressure is applied to the corrugated fiberboard S so as to perform printing on the surface of the corrugated fiberboard S. The printed corrugated fiberboard S is transferred to the slotter creaser section  31  by the feed rolls. 
     In the slotter creaser section  31 , first, when the corrugated fiberboard S passes through the first creasing line rolls  32 , as shown in  FIG. 2 , creasing lines  312 ,  313 ,  314 , and  315  are formed on the rear surface (top liner) side of the corrugated fiberboard S. In addition, when the corrugated fiberboard S passes through the second creasing line rolls  33 , the creasing lines  312 ,  313 ,  314 , and  315  are formed on the rear surface (top liner) side of the corrugated fiberboard S again. 
     Next, when the corrugated fiberboard S in which the creasing lines  312 ,  313 ,  314 , and  315  are formed passes through the first and second slotter heads  34  and  35 , grooves  322   a ,  322   b ,  323   a ,  323   b ,  324   a , and  324   b  are formed at the positions of the creasing lines  312 ,  313 , and  314 . In this case, an end portion is cut at the position of the creasing line  315 , and a gluing margin strip  325  is formed. In addition, when the corrugated fiberboard S passes through the slitter heads  36 , an end portion is cut at a position of a cutting position  311 . Accordingly, the corrugated fiberboard S includes four sheet pieces  331 ,  332 ,  333 , and  334  which have the creasing lines  312 ,  313 , and  314  (grooves  322   a ,  322   b ,  323   a ,  323   b ,  324   a , and  324   b ) as boundaries. 
     In the die cutting section  41 , when the corrugated fiberboard S passes through a portion between the anvil cylinder  43  and the knife cylinder  44 , a hand hole (not shown) is formed. However, since the hand hole processing is appropriately performed according to the kind of the corrugated fiberboard S, when the hand hole is not required, a blade attachment base (punching blade) for performing the hand hole processing is removed from the knife cylinder  44 , and the corrugated fiberboard S passes through the portion between the rotating anvil cylinder  43  and knife cylinder  44 . In addition, the corrugated fiberboard S in which the hand hole is formed is transferred to the folding section  61 . 
     In the folding section  61 , glue is applied to the gluing margin strip  325  (refer to  FIG. 2 ) by the gluing device  66  while the corrugated fiberboard S is moved in the transfer direction D by the upper transfer belt  62  and the lower transfer belts  63  and  64 , and thereafter, the corrugated fiberboards S is folded downward by the sheet folding device  65  with the creasing lines  312  and  314  (refer to  FIG. 2 ) as base points. If this folding advances to nearly 180°, the folding force becomes stronger, the gluing margin strip  325  and the end portion of the corrugated fiberboard S are pressed to each other so as to come into close contact with each other, both end portions of the corrugated fiberboard S are joined to each other, and the corrugated box B is formed. In addition, the corrugated box B is transferred to the counter-ejector section  71 . 
     In the counter-ejector section  71 , the corrugated box B is fed to the hopper device  72 , a tip portion of the corrugated box B in the transfer direction D abuts on the front stopper, and the corrugated boxes B are stacked on the elevator  73  in a state of being arranged by the angle arrangement plate. In addition, if a predetermined number of corrugated boxes B are stacked on the elevator  73 , the elevator  73  is lowered, a predetermined number of corrugated boxes B become one batch, are discharged by the ejection conveyor  74 , and are fed to the post-process of the box making machine  10 . 
     Here, the sheet folding device  65  of the present embodiment will be described in detail.  FIG. 2  is a schematic plan view showing the sheet folding device of the present embodiment,  FIG. 3  is a schematic side view showing the sheet folding device,  FIG. 4  is a sectional view taken along line Iv-Iv of  FIG. 2 , and  FIG. 5  is a schematic view showing a folding rail position adjustment device. 
     As shown in  FIGS. 2 to 4 , the sheet folding device  65  includes first folding rails  101 , second folding rails  102 , first guide plates  103 , second guide plates  104 , first gauge roller groups  105 , second gauge roller groups  106 , forming belts  107 , and folding bars  108 . 
     A pair of right and left upper transfer belts  62  is provided on an upper side in a vertical direction, and is provided over the entire length of the sheet folding device  65  in the transfer direction D. Each upper transfer belt  62  is an endless belt and is configured to be wound around several pulleys supported by a pair of right and left upper frames (not shown) so that the upper transfer belt  62  can circulate. In each of the circulating upper transfer belts  62 , a lower side thereof moves in the transfer direction D and an upper side thereof moves in a direction opposite to the transfer direction D. 
     A pair of right and left lower frames  111  facing the pair of right and left upper frames is provided vertically below the pair of right and left upper frames, and the pair of right and left upper transfer belts  62  is disposed to face the pair of right and left lower frames  111  above the pair of right and left lower frames  111 . A pair of right and left first folding rails  101  and a pair of right and left second folding rails  102  are disposed in series along the transfer direction D on both sides in the transfer direction D of the corrugated fiberboard S. The respective first folding rails  101  and the respective second folding rails  102  are supported outside the pair of right and left lower frames  111 . The respective first folding rails  101  are disposed to be approximately parallel in the transfer direction D, and the respective second folding rails  102  are disposed to be inclined such that downstream sides of the respective second folding rails  102  in the transfer direction D approach each other. In addition, downstream end portions of the respective first folding rails  101  in the transfer direction D are rotatably connected horizontally to upstream end portions of the respective second folding rails  102  in the transfer direction D by respective connection shafts  112  along the vertical direction. In addition, downstream end portions of the respective second folding rail  102  in the transfer direction D are rotatably connected horizontally to the lower frames  111  by respective connection shafts  113  along the vertical direction. 
     In the respective first folding rails  101  and the respective second folding rails  102 , positions in a width direction in a bending portion along the transfer direction D are disposed at positions in the width direction corresponding to the respective creasing lines  312  and  314  on a lower surface of the corrugated fiberboard S transferred in the transfer direction D. Accordingly, the corrugated fiberboard S is transferred while sheet pieces  331  and  334  on end portion sides in the width direction are folded downward with respect to respective sheet pieces  332  and  333  on a center side in the width direction at positions at which the respective creasing lines  312  and  314  abut against bending portions of the respective first folding rails  101  and the respective second folding rails  102 . 
     A pair of right and left first guide plates  103  and a pair of right and left second guide plates  104  are disposed in series along the transfer direction D on both sides in the transfer direction D of the corrugated fiberboard S. The respective first guide plates  103  and the respective second guide plates  104  are disposed in series along the transfer direction D on the downstream sides of the respective second folding rails  102  in the transfer direction D. The respective first guide plates  103  and the respective second guide plates  104  are supported outside the pair of right and left lower frames  111 . The respective first guide plates  103  are disposed to be approximately parallel in the transfer direction D, and the respective second guide plates  104  are disposed to be approximately parallel in the transfer direction D. However, downstream outer surface of the second guide plates  104  in the transfer direction D are formed in inclined surfaces. 
     In the respective first guide plates  103  and the respective second guide plates  104 , positions in a width direction in a bending portion along the transfer direction D are disposed at positions in the width direction corresponding to the respective creasing lines  312  and  314  on the lower surface of the corrugated fiberboard S transferred in the transfer direction D. Accordingly, the corrugated fiberboard S is transferred while the sheet pieces  331  and  334  on the end portion sides in the width direction are folded downward with respect to the respective sheet pieces  332  and  333  on a center side in the width direction at positions at which the respective creasing lines  312  and  314  abut against bending portions of the respective first guide plates  103  and the respective second guide plates  104 . 
     A pair of right and left first gauge roller groups  105  and a pair of right and left second gauge roller groups  106  are disposed in series along the transfer direction D on both sides in the transfer direction D of the corrugated fiberboard S. The respective first gauge roller groups  105  and the respective second gauge roller groups  106  are disposed so as to face each other outside the respective second folding rails  102 , the respective first guide plates  103 , and the respective second guide plates  104  in the width direction. The respective first gauge roller groups  105  include several first gauge rollers  114 , the respective second gauge roller groups  106  includes several second gauge rollers  115 , the respective gauge rollers  114  and  115  are rotatably supported by support plates  116  and  117 , and the respective support plates  116  and  117  are supported outside the respective lower frames  111 . In addition, the respective gauge rollers  114  and  115  can be driven and rotated synchronously by a drive device (not shown). 
     In the respective first gauge roller groups  105  and the respective second gauge roller groups  106 , positions in the width direction of holding portions (recessed portions) along the transfer direction D are disposed at positions in the width direction corresponding to the respective creasing lines  312  and  314  on the lower surface of the corrugated fiberboard S transferred in the transfer direction D. In addition, shapes of the holding portions in the respective first gauge roller groups  105  and the respective second gauge roller groups  106  are changed according to the shape of the folding portion of the folded corrugated fiberboard S. Accordingly, after the corrugated fiberboard S is bent downward at the positions of the respective creasing lines  312  and  314 , an outer peripheral portion (upper surface side) of the corrugated fiberboard S is held by the holding portions of the respective first gauge roller groups  105  and the respective second gauge roller groups  106 , and thus, the corrugated fiberboard S is transferred while the sheet pieces  331  and  334  on the end portion sides in the width direction are folded with respect to the respective sheet pieces  332  and  333  on the center side in the width direction. 
     A pair of right and left forming belts  107  are provided in the transfer direction D on the downstream side of the lower transfer belt  63  (refer to  FIG. 1 ) in the transfer direction D. Each forming belt  107  is an endless belt and is configured to be wound around several pulleys (not shown) supported by each lower frame  111  so that the forming belt  107  can circulate. In each of the circulating forming belts  107 , an upper side thereof moves in the transfer direction D and a lower side thereof moves in a direction opposite to the transfer direction D. The respective forming belts  107  are inclined so as to be twisted in the transfer direction D such that the respective forming belts  107  come into contact with outer surfaces (upper surfaces) of the respective sheet pieces  331  and  334  formed by bending both end portions in the width direction of the corrugated fiberboard S downward so as to face the outer surfaces. Accordingly, when the corrugated fiberboard S is transferred while being supported by the respective folding rails  101  and  102 , the respective guide plates  103  and  104 , and the respective gauge roller groups  105  and  106 , the respective forming belts  107  fold the sheet pieces  331  and  334  on the end side in the width direction while pressing the sheet pieces  331  and  334  downward and inward in order. 
     A pair of right and left folding bars  108  are provided on the downstream side in the transfer direction D, and a portion of each folding bar  108  is provided to overlap the second guide plate  104 , the first gauge roller group  105 , the second gauge roller group  106 , and the forming belt  107  in the transfer direction D. Similarly to the respective forming belts  107 , the respective folding bars  108  are provided so as to face and come into contact with the outer surfaces (the upper surfaces) of the respective sheet pieces  331  and  334  formed by bending both end portions in the width direction of the corrugated fiberboard S downward. Accordingly, when the corrugated fiberboard S is transferred while being supported by the respective folding rails  101  and  102 , the respective guide plates  103  and  104 , and the respective gauge roller groups  105  and  106 , the respective folding bars  108  press the sheet pieces  331  and  334  on the end side in the width direction downward and inward in order, in cooperation with the respective forming belts  107 . 
     In addition, a first folding rail adjustment device  121  and a second folding rail adjustment device  122  are provided, which adjust the position of each of the folding rails  101  and  102  in the width direction of the corrugated fiberboard S. The first folding rail adjustment device  121  moves the first folding rail  101  and the second folding rail  102  in parallel in the width direction of the corrugated fiberboard S so as to adjust the positions in the width direction in a state of maintaining horizontal angles of the first folding rail  101  and the second folding rail  102  in the transfer direction D. The second folding rail adjustment device  122  moves the first folding rail  101  in parallel in the width direction of the corrugated fiberboard S so as to adjust the position in the width direction in a state of maintaining the horizontal angle of the first folding rail  101  in the transfer direction D. In this case, the second folding rail adjustment device  122  moves the first folding rail  101  in the width direction of the corrugated fiberboard S, and thus, the second folding rail adjustment device  122  moves the connection shaft  112  side in the width direction of the corrugated fiberboard S with the connection shaft  113  of the second folding rail  102  as a supporting point and can adjust the position of the second folding rail  102  in the width direction and the horizontal angle of the second folding rail  102 . 
     In addition, first gauge roller adjustment devices  123 , second gauge roller adjustment devices  124 , and third gauge roller adjustment devices  125  are provided, which adjust the positions of the respective gauge roller groups  105  and  106  in the width direction of the corrugated fiberboard S. The first gauge roller adjustment devices  123  moves the first gauge roller group  105  in parallel in the width direction of the corrugated fiberboard S so as to adjust the position in the width direction in a state of maintaining a horizontal angle of the first gauge roller group  105  in the transfer direction D. The second gauge roller adjustment device  124  moves the gauge roller  114  on the upstream side of the first gauge roller group  105  in the transfer direction D in the width direction of the corrugated fiberboard S with the gauge roller  114  on the downstream side of the first gauge roller group  105  in the transfer direction D as a supporting point and adjusts a horizontal angle of the first gauge roller group  105 . The third gauge roller adjustment device  125  moves the gauge roller  115  on the downstream side of the second gauge roller group  106  in the transfer direction D in the width direction of the corrugated fiberboard S with the gauge roller  115  on the upstream side of the second gauge roller group  106  in the transfer direction D as a supporting point and adjusts a horizontal angle of the second gauge roller group  106 . 
     The first folding rail adjustment device  121 , the second folding rail adjustment device  122 , the first gauge roller adjustment device  123 , the second gauge roller adjustment device  124 , and the third gauge roller adjustment device  125  are configured to be approximately similar to each other. Here, the second folding rail adjustment device  122  will be described as an example. 
     As shown in  FIG. 5 , a supporting shaft  132  extending in the horizontal direction from the lower frame  111  penetrates a support box  131 , and the support box  131  is supported to be movable along an axial direction of the supporting shaft  132 , that is, the width direction (the horizontal direction orthogonal to the transfer direction D) of the transferred corrugated fiberboard S. The first folding rail  101  is attached to the support box  131  via a bracket  133 , and the first folding rail  101  includes a bending portion  101   a  which extends to be inclined outward and upward in the width direction. 
     A bearing portion  134  extends in the horizontal direction from the lower frame  111 , and a tip portion of bearing portion  134  is rotatably supported by a rotating shaft  135 . The rotating shaft  135  is disposed along the transfer direction D of the corrugated fiberboard S and an eccentric portion  136  is fixed to a tip portion of the rotating shaft  135 . Axis centers of the rotating shaft  135  and the eccentric portion  136  are offset from each other by a predetermined distance. An opening portion  137  is formed in the lower portion of the support box  131 , and the eccentric portion  136  is fitted into the opening portion  137 . In addition, the rotating shaft  135  can be rotated by a drive device  138 . 
     Accordingly, if the rotating shaft  135  and the eccentric portion  136  are rotated by the drive device  138 , the eccentric portion  136  oscillates with respect to the rotating shaft  135 , and thus, the support box  131  moves along the axial direction of the supporting shaft  132  by an offset amount of the axis center between the rotating shaft  135  and the eccentric portion  136 . If the support box  131  moves along the axial direction of the supporting shaft  132 , the first folding rail  101  fixed to the support box  131  moves along the width direction of the corrugated fiberboard S. The second folding rail adjustment device  122  specifies a rotation position of the eccentric portion  136  by the drive device  138 , and thus, moves the first folding rail  101  in parallel in the width direction of the corrugated fiberboard S and adjusts the position of the first folding rail  101  in the width direction. In addition, the first folding rail  101  moves in the width direction, and thus, the second folding rail adjustment device  122  moves the connection shaft  112  side in the width direction of the corrugated fiberboard S with the connection shaft  113  of the second folding rail  102  as the supporting point and can adjust the position of the second folding rail  102  in the width direction and the horizontal angle of the second folding rail  102 . 
     Similarly, the first folding rail adjustment device  121  can adjust the positions of the first folding rail  101  and the second folding rail  102  in the width direction, the first gauge roller adjustment device  123  can adjust the position of the first gauge roller group  105  in the width direction, the second gauge roller adjustment device  124  can adjust the position of the first gauge roller group  105  in the width direction and the horizontal angle of the first gauge roller group  105 , and the third gauge roller adjustment device  125  can adjust the position of the second gauge roller group  106  in the width direction and the horizontal direction angle of the second gauge roller group  106 . 
     A control device  126  is connected to the first folding rail adjustment devices  121 , the second folding rail adjustment devices  122 , the first gauge roller adjustment devices  123 , the second gauge roller adjustment devices  124 , and the third gauge roller adjustment devices  125  (refer to  FIG. 2 ). When the second folding rail  102  is moved by the second folding rail adjustment device  122  (or the first folding rail adjustment device  121 ), the control device  126  controls the second gauge roller adjustment device  124  such that a gap between the second folding rail  102  and the first gauge roller group  105  falls within a predetermined gap region which is set in advance. 
     In addition, a guide measurement sensor  127  for measuring the position of each second folding rail  102  and a roller measurement sensor  128  for measuring the position of the first gauge roller group  105  are provided, and the measurement results are output to the control device  126 . The control device  126  controls the second folding rail adjustment devices  122  and the second gauge roller adjustment devices  124  based on the positions of the second folding rails  102  and the positions of the first gauge roller groups  105 . 
     Hereinafter, an operation of the sheet folding device  65  including control methods of the second folding rail adjustment devices  122  and the second gauge roller adjustment devices  124  by the control device  126  will be described. 
     As shown in  FIGS. 2 to 4 , if the corrugated fiberboard S on which the creasing lines  312 ,  313 , and  314  are formed is guided by the upper transfer belt  62  and the lower transfer belt  63  and reaches the first folding rails  101 , the corrugated fiberboard S is transferred such that the respective creasing lines  312  and  314  abut against the bending portions of the respective first folding rails  101 . In addition, in a process in which the corrugated fiberboard S is transferred on the respective first folding rails  101  and the respective second folding rails  102 , the respective forming belt  107  press the sheet pieces  331  and  334  on the end portion sides in the width direction of the corrugated fiberboard downward and the respective folding bars  108  press the sheet pieces  331  and  334  on the end portion sides in the width direction downward in cooperation with the respective forming belts  107 . 
     Accordingly, in the corrugated fiberboard S, the sheet pieces  331  and  334  on the end portion sides in the width direction are folded downward with respect to the respective sheet pieces  332  and  333  on the center side in the width direction at positions at which the respective creasing lines  312  and  314  abut against bending portions of the respective first folding rails  101  or the respective second folding rails  102 , and thus, the folding portion is formed. In addition, in a process in which the corrugated fiberboard S is transferred on the respective second folding rails  102 , an outer peripheral portion of the folding portion is held in order by the holding portions (recessed portion) of the respective first gauge roller groups  105  and the respective second gauge roller groups  106 , and thus, the sheet pieces  331  and  334  on the end portion sides in the width direction are folded so as to come into contact with the respective sheet pieces  332  and  333  on the center side in the width direction. In this way, a flat corrugated box is formed. 
     However, the corrugated fiberboard S has different rigidities according to a thickness, a nature, a shape, or the like of a liner or a core paper constituting the corrugated fiberboard S. When the corrugated fiberboard S having a high rigidity is clamped by the respective second folding rails  102  and the respective first gauge roller groups  105 , the corrugated fiberboard S is appropriately bent at the positions of the respective creasing lines  312  and  313 . However, when the corrugated fiberboard S having a low rigidity is clamped by the respective second folding rails  102  and the respective first gauge roller groups  105 , the corrugated fiberboard S is bent inside the respective creasing lines  312  and  313 . 
       FIGS. 7A and 7B  are schematic views showing a bending state of a corrugated fiberboard in the related art. In  FIG. 7 , an upper cross section indicates a position of the most upstream first gauge roller  114  in the first gauge roller group  105 , an intermediate cross section indicates a position of the first gauge roller  114  facing the first guide plate  103 , and a lower cross section indicates a position of the second gauge roller  115  facing the second guide plate  104 . 
     As shown in  FIG. 7A , first, the corrugated fiberboard S is clamped by a bending portion  102   a  of the second folding rail  102  and a recessed portion  114   a  of the first gauge roller  114 , and thus, the sheet piece  334  is bent by approximately 90° with respect to the sheet piece  333 . Next, the corrugated fiberboard S is clamped by the first guide plate  103  and the recessed portion  114   a  of the first gauge roller  114 , and thus, the sheet piece  334  is bent by 90° or more with respect to the sheet piece  333 . In addition, the corrugated fiberboard S is clamped by the second guide plate  104  and a recessed portion  115   a  of the second gauge roller  115 , and thus, the sheet piece  334  is further bent with respect to the sheet piece  333 . 
     In this case, in a case where the rigidity of the corrugated fiberboard S is low, when the corrugated fiberboard S is clamped by the bending portion  102   a  of the second folding rail  102  and the recessed portion  114   a  of the first gauge roller  114  and is bent, the corrugated fiberboard S is bent at a position offset by a width W 1  inward from a position (reference position O) of the creasing line  314 . Accordingly, when the corrugated fiberboard S is clamped by the first guide plate  103  and the recessed portion  114   a  of the first gauge roller  114 , a gap is generated between the corrugated fiberboard S and the first gauge roller  114 , and thus, when the corrugated fiberboard S is clamped by the second guide plate  104  and the second gauge roller  115 , the bending position is scattered. 
     In this case, in the related art, as shown in  FIG. 7A , the second folding rail  102  moves outward in the width direction and the first gauge roller  114  moves outward in the width direction. Accordingly, when the corrugated fiberboard S is clamped by the bending portion  102   a  of the second folding rail  102  and the recessed portion  114   a  of the first gauge roller  114  and is bent, the corrugated fiberboard S is appropriately bent at the position (reference position O) of the creasing line  314 . However, when the corrugated fiberboard S is clamped by the first guide plate  103  and the recessed portion  114   a  of the first gauge roller  114 , a gap is generated between the corrugated fiberboard S and the first gauge roller  114  which moves outward in the width direction, and thus, when the corrugated fiberboard S is clamped by the second guide plate  104  and the second gauge roller  115 , the bending position is scattered. 
     Accordingly, in the present embodiment, when the rigidity of the corrugated fiberboard S is low, the second folding rail  102  moves outward in the width direction, and a predetermined gap is maintained between the first guide plate  103  and the first gauge roller  114  is maintained while the first gauge roller  114  positioned at a position facing the second folding rail  102  moves outward in the width direction. 
       FIG. 6  is an explanatory view showing a position adjustment method of the folding rails and the gauge rollers, and  FIG. 8  is a schematic view showing a bending state of the corrugated fiberboard of the present embodiment. In addition, in  FIG. 8 , the upper cross section, the intermediate cross section, and the lower cross section are positioned at positions similar to those of  FIGS. 7A and 7B . 
     As shown in  FIGS. 6 and 8 , when the corrugated fiberboard S having a low rigidity is processed, the second folding rail  102  is rotated outward about the connection shaft  113  via the first folding rail  101  by the second folding rail adjustment device  122 , and for example, the bending portion  102   a  of the second folding rail  102  moves to the position (reference position O) of the creasing line  314 . In addition, according to this, the first gauge roller group  105  is rotated outward about a supporting point  105   a  by the second gauge roller adjustment device  124 , and the first gauge roller  114  facing the second folding rail  102  moves outward in the width direction. In this case, the gap between the second folding rail  102  and the first gauge rollers  114  facing each other falls within a predetermined gap region which is set in advance. 
     In addition, the first gauge roller group  105  rotates outward about the supporting point  105   a , the first gauge roller  114  facing the second folding rail  102  largely moves outward in the width direction, and an appropriate gap between the first gauge roller  114  and the second folding rail  102  is maintained. Meanwhile, in the first gauge roller group  105 , the respective first gauge rollers  114  disposed on the supporting point  105   a  side hardly move outward in the width direction, and thus, the first gauge roller group  105  is hardly separated from the first guide plate  103 , and an appropriate gap is maintained. 
     Accordingly, as shown in  FIG. 8 , first, the corrugated fiberboard S, the corrugated fiberboard S is clamped by the bending portion  102   a  of the second folding rail  102  which has moved outward in the width direction and the recessed portion  114   a  of the first gauge roller  114  which has moved outward in the width direction, and thus, the sheet piece  334  is bent appropriately at approximately 90° at the position (reference position O) of the creasing line  314  with respect to the sheet piece  333 . Next, the corrugated fiberboard S is clamped by the first guide plate  103  and the recessed portion  114   a  of the first gauge roller  114  which hardly moves outward in the width direction, and thus, the gap is not generated between the corrugated fiberboard S and the first gauge roller  114 , and the sheet piece  334  is bent by 90° or more with respect to the sheet piece  333 . In addition, the corrugated fiberboard S is clamped by the second guide plate  104  and the recessed portion  115   a  of the second gauge roller  115 , the sheet piece  334  is bent at an appropriate position with respect to the sheet piece  333 , and the bending position is not scattered. 
     In addition, in the above-described embodiment, when the second folding rail  102  moves outward in the width direction, the upstream side of the first gauge roller group  105  in the transfer direction D is moved outward in the width direction of the corrugated fiberboard S about the supporting point  105   a  of the first gauge roller group  105  on the downstream side in the transfer direction D by the second gauge roller adjustment device  124 . However, the present invention is not limited to this.  FIG. 9  is a schematic view showing a first modification example of the sheet folding device of the present embodiment, and  FIG. 10  is a schematic view showing a second modification example of the sheet folding device of the present embodiment. 
     In the first modification example, as shown in  FIG. 9 , when two first gauge rollers  114  of the first gauge roller group  105  positioned on the most upstream side in the transfer direction D of the corrugated fiberboard S face the second folding rail  102  in the width direction, in the first gauge roller group  105 , the two first gauge rollers  114  on the most upstream side can integrally rotate with the third first gauge roller  114  from the most upstream side in the transfer direction D of the corrugated fiberboard S as a supporting point  105   b . Accordingly, when the second folding rail  102  moves outward in the width direction, only the two first gauge rollers  114  facing the second folding rail  102  move outward in the width direction, and other first gauge rollers  114  can be maintained at positions thereof. 
     In addition, in the second modification example, as shown in  FIG. 10 , when the two first gauge rollers  114  of the first gauge roller group  105  positioned on the most upstream side in the transfer direction D of the corrugated fiberboard S face the second folding rail  102  in the width direction, the two first gauge rollers  114  on the upstream side can integrally move in parallel along the width direction. Accordingly, when the second folding rail  102  moves outward in the width direction, only the two first gauge rollers  114  facing the second folding rail  102  move outward in the width direction, and other first gauge rollers  114  can be maintained at positions thereof. 
     In addition, in the above-described embodiment, the respective gauge rollers  114  and  115  of the respective gauge roller groups  105  and  106  come into direct contact with the bending portion of the corrugated fiberboard S to be guided. However, the present invention is not limited to this configuration.  FIG. 11  is a schematic view showing a third modification example of the sheet folding device of the present embodiment, and  FIG. 12  is a sectional view of a gauge roller. 
     As shown in  FIGS. 11 and 12 , the first gauge roller group  105  includes several first gauge rollers  114 , and a holding belt  142  is wound around the respective first gauge rollers  114  and a tension roller  141 . The recessed portion  114   a  for holding the bending portion of the corrugated fiberboard S is provided in each first gauge roller  114 , and the recessed portion  114   a  includes a lower surface portion  151 , a bottom surface portion  152 , and an inclined surface portion  153 . In addition, in each first gauge roller  114 , the holding belt  142  is wound around the bottom surface portion  152  of the recessed portion  114   a . In addition, the drive device  143  is drivingly connected to one first gauge roller  114  of the several first gauge rollers  114 . 
     Accordingly, if the one first gauge roller  114  is driven by the drive device  143 , all the first gauge rollers  114  can be synchronously rotated via the holding belt  142 . In addition, the bending portion of the corrugated fiberboard S is continuously supported by the holding belt  142  provided on the recessed portions  114   a  of the respective first gauge rollers  114 , the corrugated fiberboard S does not fall between the respective first gauge rollers  114 , and a posture of the corrugated fiberboard S does not deteriorate. 
     In addition, here, the tension roller  141 , the holding belt  142 , the drive device  143  is provided in the first gauge roller group  105 , but may be also applied to the second gauge roller group  106 . 
     In this way, the sheet folding device of the present embodiment includes the folding rails  101  and  102  which are disposed along the transfer direction D on both sides in the transfer direction D of the corrugated fiberboard S, the guide plates  103  and  104  which are disposed on downstream sides of the folding rails  101  and  102  along the transfer direction D on both sides in the transfer direction D of the corrugated fiberboard S, the gauge roller groups  105  and  106  including several gauge rollers  114  and  115  which are disposed outside the folding rails  101  and  102  and the guide plates  103  and  104  in a width direction of the corrugated fiberboard S, along the transfer direction D of the corrugated fiberboard S, the folding rail adjustment devices  121  and  122  which adjust the positions of the folding rails  101  and  102  in the width direction of the corrugated fiberboard, and the second gauge roller adjustment device  124  which adjusts the position of at least the gauge roller  114  of the gauge roller groups  105  and  106 , which is disposed to face the second folding rail  102 , in the width direction of the corrugated fiberboard S. 
     Accordingly, when the position of the second folding rail  102  in the width direction is adjusted by the second folding rail adjustment device  122 , the position in the width direction of the first gauge roller  114  of the first gauge roller group  105  facing the second folding rail  102  is adjusted by the second gauge roller adjustment device  124 . Accordingly, even when the positions of the second folding rail  102  and the first gauge roller  114  facing each other or the gap therebetween is adjusted according to a material or the like of the corrugated fiberboard S, the gap between the first guide plate  103  and the first gauge roller  114  is maintained at an appropriate gap, the corrugated fiberboard S can be bent at an appropriate position, and it is possible to improve bending accuracy of the corrugated fiberboard S. 
     In the sheet folding device of the present embodiment, the second gauge roller adjustment device  124  can move the upstream side of the first gauge roller group  105  close to or away from the second folding rail  102  with the downstream side of the first gauge roller group  105  in the transfer direction D of the corrugated fiberboard S as the supporting points  105   a  and  105   b . Accordingly, when the position of the second folding rail  102  in the width direction is adjusted, the first gauge roller group  105  rotates with the downstream side as the supporting point, the position of the first gauge roller  114  on the upstream side in the width direction is adjusted, the position of the first gauge roller  114  facing the second folding rail  102  can be appropriately adjusted, and it is possible to bend the corrugated fiberboard S at an appropriate position without largely changing the position of the first gauge roller  114  facing the first guide plate  103 . 
     In the sheet folding device of the present embodiment, the second gauge roller adjustment device  124  can move the first gauge roller  114  of the first gauge roller group  105  disposed to face the second folding rail  102  close to or away from the second folding rail  102 . Accordingly, when the position of the second folding rail  102  in the width direction is adjusted, only the first gauge roller  114  disposed to face the second folding rail  102  moves and the position thereof in the width direction is adjusted, the position of the first gauge roller  114  facing the second folding rail  102  can be appropriately adjusted, and it is possible to bend the corrugated fiberboard S at an appropriate position without changing the position of the first gauge roller  114  facing the first guide plate  103 . 
     In the sheet folding device of the present embodiment, the first folding rail  101  and the second folding rail  102  which are disposed in series and have the end portions rotatably connected to each other are provided as the second folding rail, the first folding rail adjustment device  121  can move the first folding rail  101  and the second folding rail  102  in parallel in the width direction, and the second folding rail adjustment device  122  can change the angle of the second folding rail  102  by moving the first folding rail  101  in parallel in the width direction. Accordingly, the first folding rail  101  and the second folding rail  102  move in parallel in the width direction, the first folding rail  101  moves in parallel in the width direction so as to change the angle of the second folding rail  102 , and it is possible to easily adjust the position of the first gauge roller  114  facing the second folding rail  102 . 
     In the sheet folding device of the present embodiment, the first gauge roller group  105  and the second gauge roller group  106  which are disposed in series are provided as the gauge roller group, the first gauge roller adjustment device  123  can move the first gauge roller group  105  in parallel in the width direction, and the second gauge roller adjustment device  124  can change the angle of the first gauge roller group  105 . Accordingly, the angle of the first gauge roller group  105  is changed, and thus, it is possible to easily adjust the position of the gauge roller  114  facing the second folding rail  102 . 
     In the sheet folding device of the present embodiment, the control device  126  which controls the folding rail adjustment devices  121  and  122  and the gauge roller adjustment device  123 ,  124 , and  125  is provided, and the control device  126  controls the second gauge roller adjustment device  124  such that the gap between the second folding rail  102  and the first gauge roller  114  when the second folding rail  102  is moved by the second folding rail adjustment device  122  falls within a predetermined gap region which is set in advance. Accordingly, the position of the second folding rail  102 , the position of the first gauge roller  114 , and the gap between the second folding rail  102  and the first gauge roller  114  can be easily adjusted to appropriate positions or an appropriate gap, and thus, workability can be improved. 
     In the sheet folding device of the present embodiment, the guide measurement sensor  127  which measures the position of the second folding rail  02 , the roller measurement sensor  128  which measure the position of the first gauge roller group  105 , and the control device  126  which controls the second folding rail adjustment device  122  and the second gauge roller adjustment device  124  based on the measurement result of the guide measurement sensor  127  and the measurement result of the roller measurement sensor  128  are provided. Accordingly, it is possible to accurately adjust the position of the second folding rail  102 , the position of the first gauge roller  114 , and the gap between the second folding rail  102  and the first gauge roller  114 , and it is possible to improve quality of a product. 
     In the sheet folding device of the present embodiment, the recessed portion  114   a  holding the bending portion of the corrugated fiberboard S is provided in each of the several first gauge rollers  114 , and the holding belt  142  is wound around the bottom surface portion  152  of the recessed portion  114   a  of each of the several first gauge rollers  114 . Accordingly, the corrugated fiberboard S is transferred while the bending portion is continuously supported by the holding belt  142  provided in the recessed portion  114   a  of each gauge roller  114 , the corrugated fiberboard S does not fall between the respective first gauge rollers  114 , the posture of the corrugated fiberboard S does not deteriorate, and the corrugated fiberboard S can be stably transferred. 
     In the sheet folding device of the present embodiment, the drive device  143  which drives the first gauge roller  114  is provided. Accordingly, if the one first gauge roller  114  is driven by the drive device  143 , the drive force is transmitted to all the first gauge rollers  114  via the holding belt  142 , all the first gauge rollers  114  can be synchronously rotated, the drive system of the first gauge roller  114  is simplified, and a cost can be reduced. 
     In addition, in the box making machine of the present embodiment, the sheet feeding section  11 , the printing section  21 , the slotter creaser section  31 , the die cutting section  41 , the folding section  61 , and the counter-ejector section  71  are provided, the sheet folding device  65  is provided in the folding section  61 . Accordingly, the printing is performed on the corrugated fiberboard S from the sheet feeding section  11  in the printing section  21 , the creasing line processing and the slicing are performed in the slotter creaser section  31 , the corrugated fiberboard S is folded in the folding section  61  such that the end portions are joined to each other so as to form the corrugated box B, and the corrugated boxes B are stacked while being counted in the counter-ejector section  71 . In this case, even when the positions of the second folding rail  102  and the first gauge roller  114  facing each other or the gap therebetween is adjusted according to a material or the like of the corrugated fiberboard S, the sheet folding device  65  maintains the gap between the first guide plate  103  and the first gauge roller  114  at an appropriate gap and can bend the corrugated fiberboard S at an appropriate position, it is possible to improve bending accuracy of the corrugated fiberboard S, and it possible to improve the quality of the product. 
     In addition, in the above-described embodiment, each of the first folding rail adjustment device  121 , the second folding rail adjustment device  122 , the first gauge roller adjustment device  123 , the second gauge roller adjustment device  124 , and the third gauge roller adjustment device  125  is configured of an eccentric type device. However, the present invention is not limited to this, and for example, a screw type device, a cylinder type device, or the like may be adopted. 
     In addition, in the above-described embodiment, the folding rails  101  and  102 , the guide plates  103  and  104 , and the gauge roller groups  105  and  106  are divided into two. However, the present invention is not limited to this configuration, and may be into three or more. 
     In addition, in the above-described embodiment, the box making machine  10  includes the sheet feeding section  11 , the printing section  21 , the slotter creaser section  31 , the die cutting section  41 , the folding section  61 , and the counter-ejector section  71 . However, the present invention is not limited to this configuration. For example, in a case where the corrugated fiberboard S does not require a hand hole, the die cutting section  41  may be omitted. In addition, the box making machine  10  may include only the sheet feeding section  11 , the printing section  21 , and the slotter creaser section  31 .