Patent Publication Number: US-7216470-B2

Title: Sheet package producing system

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a sheet package producing system. More particularly, the present invention relates to a sheet package producing system for producing a sheet package having a stack of sheets at a low cost and in a manner with compatibility to various sheet types. 
     2. Description Related to the Prior Art 
     X-ray films, printing sheets or other products of a sheet shape are shipped in a form of a sheet package by stacking those in a plurality. For example, continuous photosensitive material to be the X-ray film is prepared in a roll form, and cut into sheets of a regular length. The sheets are stacked in a plurality. A protective cover is loaded with the sheets to form a covered sheet stack. The protective cover is used for preventing the X-ray film from being bent or folded, and from being scratched. The covered sheet stacked is wrapped in a light-shielding packaging bag, and is enclosed tightly. The packaging bag is inserted in an outer box, and is shipped. 
     A producing system for the sheet package of the X-ray film include a slitting device, a cutting/stacking device, a bag packaging machine, a box forming device, a box packaging machine and a cardboard caser. The slitting device slits web of photosensitive material with a great width into continuous sheets with a width of a sheet size. The cutting/stacking device cuts the continuous sheets into the sheets, and stacks the sheets in the predetermined number. The bag packaging machine closes a bag by sealing in a pillow shape or sealing three edges. The box forming device produces the outer box for containing the X-ray film. The box packaging machine inserts the X-ray film into the outer box. The cardboard caser inserts the outer box with the X-ray film into a cardboard box. 
     The bag packaging machine, which is disposed downstream in the producing system for the sheet package, operates for one time while the cutting/stacking device creates a predetermined number of the sheets by cutting. It is necessary to change over the bag packaging machine rapidly specifically for production at the sheet size being different, or in a multi-type manner. Therefore, recently used types of the bag packaging machine have had a gradual tendency of enlargement in the size, raise in complexity, and raise in performance. There is a suggestion in JP-A 5-051021 to install a plurality of the cutting/stacking device in an upstream station. Paths of the sheets from the cutting/stacking device are joined up as a single path at the bag packaging machine. 
     The number of the sheet size of the X-ray film is small. It is general that the producing system is structured in a specialized manner for a predetermined size of the sheet size. In the producing system for the X-ray film, the protective cover is pre-bent at a target end portion to be folded. The sheets are stacked on the protective cover after the pre-bending. Then the protective cover is folded before forming the sheet package. 
     In the producing system including the cutting/stacking device in the plurality, the ability of processing of the bag packaging machine is considered as minimum ability. If a difference occurs between the ability and that required in view of profits, it requires a remarkably large space for installation, and also expenses for investment. Furthermore, the facilities with the producing system are hard to maintain in a stable state. This is the case typically because the personnel having high skill in monitoring and handling the producing system cannot be easily employed. 
     For multi-type production, frequent changes are inevitable in the bag packaging machine about the sheet size and the type. It is likely that the sheet size or the type is different between the bag packaging machine and the cutting/stacking device operating at the same time. The X-ray film different in the sheet size or the type at the time of processing in the bag packaging machine is stored in a temporary manner. This results in precise administration of addresses of the X-ray film in the reservoir, precision in planning the production with judgement in priority of plural processes, precision in the administration of the production in relation to instructions, monitoring of achievements and the like, and complexity in systemizing the administration of information. To reserve the X-ray film requires sufficient spaces, which is likely to be inconsistent to rapidity in shipment of the X-ray film. 
     The producing system specialized for the X-ray film has low compatibility with the producing system for products other than the X-ray film. If a new product of the X-ray film is developed, the producing system cannot be applied in the initially specialized structure. A problem arises in a short period of using the same facilities of the producing system. 
     SUMMARY OF THE INVENTION 
     In view of the foregoing problems, an object of the present invention is to provide a sheet package producing system for producing a sheet package having a stack of sheets at a low cost and in a manner with compatibility to various sheet types. 
     In order to achieve the above and other objects and advantages of this invention, a sheet package producing system for producing a sheet package having a predetermined number of sheets is provided. A cutting/stacking device forms the sheets by cutting continuous sheet at a regular length, and for stacking the sheets in the predetermined number. A covered sheet stack producing device inserts the stacked sheets into a protective cover, to obtain a covered sheet stack. A packaging device packages the covered sheet stack to obtain the sheet package. The cutting/stacking device, the covered sheet stack producing device and the packaging device are connected in series with one another. 
     The cutting/stacking device, the covered sheet stack producing device and the packaging device are balanced in line capacity balance relative to one another. 
     The protective cover includes transversely extending plural bending lines for defining first, second and third portions, the first portion being positioned on an end face of the stacked sheets, the second and third portions being positioned on upper and lower faces of the stacked sheets. The covered sheet stack producing device includes a first handling module for placing either one of the second portion and the stacked sheets on an upper surface of a remaining one thereof. A folding module folds the protective cover along the plural bending lines, and squeezes the stacked sheets between the second and third portions, to obtain the covered sheet stack. 
     The cutting/stacking device includes a supply module for feeding the continuous sheet. A cutter module cuts the continuous sheet to obtain the sheets. A stacker module stacks the sheets in the predetermined number. 
     The first handling module places the protective cover on the stacked sheets. Furthermore, a second handling module is robotic, turns over a sheet orientation of the stacked sheets to locate the protective cover under the stacked sheets, and then sets the protective cover and the stacked sheets to the folding module. The folding module folds the protective cover by moving upward the third portion. 
     The cutting/stacking device further includes a synchronizing unit for synchronizing the supply module, the cutter module and the stacker module with one another. 
     The supply module, the cutter module and the stacker module include respectively drive power sources. The synchronizing unit electrically synchronizes the drive power sources. 
     In another preferred embodiment, the supply module, the cutter module and the stacker module include respectively first, second and third mechanisms being rotatable or movable. The cutting/stacking device includes a drive power source for actuating one of the first, second and third mechanisms. The synchronizing unit includes a transmission coupling for mechanically transmitting force of driving of the one mechanism to remaining ones of the first, second and third mechanisms. 
     The one mechanism is the second mechanism. 
     The covered sheet stack producing device further includes a pre-bending module, actuated earlier than the folding module, for bending the protective cover temporarily by forcibly depressing the third portion. The first handling module sets the protective cover on the pre-bending module, and then places the protective cover on the stacked sheets. 
     The second handling module includes a sheet chuck for capturing the stacked sheets. A moving robot arm moves the sheet chuck. A rotating mechanism is secured to the sheet chuck or the moving robot arm, for rotating the sheet chuck to turn over the sheet orientation. 
     The first handling module includes a cover suction pad for sucking the protective cover. A cover moving robot arm moves the cover suction pad. 
     The packaging device includes a bag packaging machine for packaging the covered sheet stack in a packaging bag. A box packaging machine packages the covered sheet stack in an outer box after packaging in the packaging bag, to obtain the sheet package. 
     The bag packaging machine includes a stack feeding module for feeding the covered sheet stack. A bag-forming/inserting module wraps the covered sheet stack with bag material. A package finishing module folds a margin flap of the bag material wrapping the covered sheet stack, to enclose the covered sheet stack in the packaging bag. 
     The box packaging machine includes a box forming module, being robotic, for forming the outer box by bending a plate material or sheet material. A box inserting module inserts the covered sheet stack into the outer box after packaging in the packaging bag. 
     The cutting/stacking device further includes a decurler module for eliminating or reducing a curling tendency of the continuous sheet. 
     Each of the cutting/stacking device, the covered sheet stack producing device and the packaging device includes plural modules. A pallet is disposed in each of the plural modules, having a size predetermined in consideration of a maximum size of the sheets, for supporting the continuous sheet, the sheets, the protective cover, the covered sheet stack or the sheet package. 
     In an alternative structure, the protective cover includes a transversely extending bending line for defining first and second portions, the bending line being adapted to folding, to oppose the first and second portions to one another. The covered sheet stack producing device includes a first handling module, being robotic, for placing either one of the first portion and the stacked sheets on an upper surface of a remaining one thereof. A folding module folds the protective cover along the bending line, and squeezes the stacked sheets between the first and second portions, to obtain the covered sheet stack. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The above objects and advantages of the present invention will become more apparent from the following detailed description when read in connection with the accompanying drawings, in which: 
         FIG. 1  is a perspective illustrating a sheet package producing system; 
         FIG. 1A  is a diagram schematically illustrating modules in a cutting/stacking device and flexible couplings for transmission; 
         FIG. 1B  is a diagram schematically illustrating another preferred embodiment in which the modules are electrically synchronized; 
         FIG. 2  is a perspective illustrating processes of producing a sheet package from sheets and a protective cover; 
         FIG. 3  is a perspective illustrating a stacker and a sheet handling module about to capture sheets at the stacker; 
         FIG. 4  is a perspective illustrating a cover handling module supplying the protective cover; 
         FIG. 5  is a perspective illustrating a pre-bending module operating in cooperation with the cover handling module; 
         FIG. 6  is a perspective illustrating the cover handling module placing the protective cover to the sheets handled by the sheet handling module; 
         FIG. 7  is a perspective illustrating the sheet handling module and a folding module folding the protective cover; 
         FIG. 8  is a perspective illustrating the folding module, a stack feeding module and a bag-forming/inserting module; 
         FIG. 9  is a perspective illustrating a process of packaging the sheet package to obtain a packaging bag; and 
         FIG. 10  is a perspective illustrating a process of forming a blank sheet into an outer box and inserting the packaging bag. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT(S) OF THE PRESENT INVENTION 
     In  FIG. 1 , an X-ray film producing system is schematically illustrated. The system includes a slitting device  2 , a cutting/stacking device  3 , a covered sheet stack producing device  4 , a bag packaging machine  5  and a box packaging machine  6 , the bag packaging machine  5  and the box packaging machine  6  constituting a packaging device. Those devices are balanced in relation to the line capacity balance, and are connected in series. Due to this, substantially no reservation of the material occurs between the devices. Also, the slitting device  2 , the cutting/stacking device  3 , the covered sheet stack producing device  4  and the bag packaging machine  5  are disposed in a dark room or dark compartment and shielded from light. 
     Web  8  with a great width as uncut material of X-ray film is fed in the slitting device  2 . Slitting blades  9  of the slitting device  2  slit the web  8  at a width of each X-ray film as product. A continuous sheet  10  is obtained. A spool  12  is set in a continuous sheet container  11 , and winds the continuous sheet  10  in a roll form. After this, the continuous sheet container  11  is removed from the slitting device  2  and set into the cutting/stacking device  3 . 
     The cutting/stacking device  3  is constituted by various modules which are a supply module  14 , a decurler module or uncurler module  15 , a cutter module  16  and a stacker module  17 . The supply module  14  is provided with the continuous sheet container  11  containing the continuous sheet  10 . There is a regular tension control mechanism which applies predetermined tension to the continuous sheet  10 . The continuous sheet  10  is drawn from the continuous sheet container  11  in a state with the tension. The supply module  14  includes a splicing unit for connecting a rear end of the continuous sheet  10  with a front end of a new continuous sheet when the remainder of the continuous sheet  10  decreases and comes near to the minimum. 
     A heating roller  19  and a cooler are included in the decurler module  15 . The heating roller  19  is heated at a temperature lower than that which would influence the quality of the X-ray film. The heating roller  19  contacts the continuous sheet  10  kept curved, to uncurl the continuous sheet  10 . After the heating roller  19  operates, the cooler cools the continuous sheet  10  and keeps the uncurled state of the continuous sheet  10 . A dancer roller  20  is disposed upstream from the heating roller  19 , and absorbs small changes in the tension of the continuous sheet  10 . 
     The cutter module  16  includes a suction drum  22  and a rotary oscillation cutter  23 . The suction drum  22  operates for feeding the continuous sheet  10  at a regular rate. The rotary oscillation cutter  23  is actuated in synchronism with the suction drum  22  electrically and mechanically. The continuous sheet  10  is cut by the rotary oscillation cutter  23  at a regular length, to be sheets  25  or X-ray films. See  FIG. 2 . Furthermore, corners of the sheets  25  are rounded by cutting. 
     The stacker module  17  includes stackers  27  and  28  and a sorting gate. The stackers  27  and  28  receive the sheets  25  from the cutter module  16 , and reserve the sheets  25  in a stacked state. The sorting gate guides the sheets  25  to an appropriate one of the stackers  27  and  28 . In  FIG. 3 , the stacker  27  includes a quadrilateral pallet  27   a  and guide ridges  27   b ,  27   c  and  27   d . The quadrilateral pallet  27   a  has an upper surface where the sheets  25  are stacked. The guide ridges  27   b – 27   d  regulate three edges of the sheets  25  on the quadrilateral pallet  27   a . The stacker  28  is structurally the same as the stacker  27 . Also, an ejection gate is disposed in the stacker module  17  for ejecting sheets of irregular sizes from the manufacturing line. 
     The supply module  14 , the decurler module  15 , the cutter module  16  and the stacker module  17  has a pallet or base plate having a common size determined in consideration of the expected maximum size of an X-ray film. Each of the modules can be added, removed or exchanged easily by retention with bolts. 
     In  FIG. 1A , a motor  94  as drive power source is disposed in the cutter module  16  for driving the cutting/stacking device  3 . A drive main shaft  116  is included in the cutter module  16 , and connected with the motor  94 . Drive main shafts  114 ,  115  and  117  are disposed in respectively the supply module  14 , the decurler module  15  and the stacker module  17 , and have such an arrangement that a size of a space occupied by those is equal. Flexible couplings or transmission couplings  92  as synchronizing unit of a single type are provided, and interconnect respectively two adjacent shafts included in the drive main shafts  114 – 117 . Thus, the force of driving of the motor  94  is transmitted to the supply module  14 , the decurler module  15  and the stacker module  17 , which can be synchronized. 
     Control units are associated with respectively the supply, decurler, cutter and stacker modules  14 – 17  in a separate manner. A main control unit for administrating the whole of the producing system is provided. The separate control units are connected to the main control unit, and receive signals for a start and stop of operation, and command of speed. For other items of the control, the separate control units operate per each of workpieces. Note that the supply, decurler, cutter and stacker modules  14 – 17  may be synchronized by other constructions than the flexible couplings  92  and the drive main shafts  114 – 117 . In  FIG. 1B , the motor  94  is incorporated in each of the supply, decurler, cutter and stacker modules  14 – 17 . A synchronizing unit  90  operates for control between invertors, and synchronizes the plurality of the motors  94  electrically. 
     The covered sheet stack producing device  4  is constituted by a sheet handling module  30 , a cover handling module  31 , a pre-bending module  33  and a folding module  34 . The sheet handling module  30  captures a stack of the sheets  25  from the stacker module  17  in the cutting/stacking device  3 . A protective cover  32  is handled by the cover handling module  31 . The pre-bending module  33  pre-bends the protective cover  32  before folding in the final step. The folding module  34  folds the protective cover  32  loaded with the sheets  25 . 
     In  FIG. 3 , the sheet handling module  30  is constituted by a general-purpose robot or six-axis vertically articulated type of robot with a sheet moving robot arm  36  of a bendable structure. The sheet moving robot arm  36  includes a first joint  37 , a second joint  38 , a third joint  39  and rotational pivots  40  and  42 . The rotational pivot  40  is disposed between the first joint  37  and the second joint  38 . A base plate  41  is provided, on which the rotational pivot  42  keeps the sheet moving robot arm  36  rotatable. A sheet chuck  44  is fixed on a distal end of the sheet moving robot arm  36 , and squeezes and handles a stack of the sheets  25 . The sheet chuck  44  includes chuck plates  45   a ,  45   b ,  45   c  and  45   d  and protection ridges  46 . The chuck plates  45   a ,  45   b ,  45   c  and  45   d  contact front and rear surfaces of the sheets  25 . The protection ridges  46  project from the chuck plates  45   c  and  45   d , and regulate lateral edges of the sheets  25 . The chuck plates  45   c  and  45   d  are stationary. The chuck plates  45   a  and  45   b  are movable up and down with reference to the chuck plates  45   c  and  45   d.    
     Grooves  27   e  and  27   f  are formed in the quadrilateral pallet  27   a  of the stacker  27 . The sheet handling module  30  inserts the chuck plates  45   c  and  45   d  into the grooves  27   e  and  27   f . Then the chuck plates  45   a  and  45   b  are moved down toward the chuck plates  45   c  and  45   d , to squeeze the sheets  25 . The joints of the sheet moving robot arm  36  are actuated, to pick up the sheets  25  from the stacker  27 . 
     In  FIG. 4 , the cover handling module  31  is constituted by a general-purpose robot with a cover moving robot arm  48  of a bendable structure. The cover moving robot arm  48  includes a first joint  49 , a second joint  50 , a third joint  51  and rotational pivots  52  and  54 . The rotational pivot  52  is disposed between the first joint  49  and the second joint  50 . A base plate  53  is provided, on which the rotational pivot  54  keeps the cover moving robot arm  48  rotatable. Cover suction pads  55  are fixed on a distal end of the cover moving robot arm  48 , and suck and hold an uppermost one of the protective cover  32  by suction of air. Note that the cover handling module  31  may include the same general-purpose robot as the sheet handling module  30 . Again, the cover suction pads  55  are used with the robot of this type. 
     The protective cover  32  consists of a sufficiently thick plate with rigidity, such as a cardboard. In  FIG. 2 , quadrilateral boards  57  are prepared as raw material, and are cut into the protective cover  32  nearly in a trapezoidal shape. The protective cover  32  is bent at four portions to protect the front and rear surfaces of the sheets  25  and one of their lateral edge. 
     In  FIG. 5 , the pre-bending module  33  includes a base  59 , a bender plate  60 , and a moving mechanism. The base  59  contacts a lower surface of the protective cover  32 . The bender plate  60  moves down to lap an end face of the base  59 . The moving mechanism moves the bender plate  60 . The cover handling module  31  moves a target end portion of the protective cover  32  to the base  59  of the pre-bending module  33 , and sets the same positioned. After this, the bender plate  60  moves down toward the base  59 , to bend the target end portion in a preliminary or pre-bending manner. The cover handling module  31  sets the target end portion of the protective cover  32  on the pre-bending module  33  one cover after another. Finally, all of the plurality of the protective covers  32  are bent preliminarily. 
     In  FIG. 6 , the protective cover  32  after being pre-bent is placed by the cover handling module  31  on to the sheets  25  grasped by the sheet chuck  44  of the sheet handling module  30 . The sheet chuck  44  is actuated again to squeeze the sheets  25  and the protective cover  32  together. In  FIG. 7 , the sheet handling module  30  causes the sheet chuck  44  to make half a rotation by means of the rotational pivot  40 , to turn over the sheets  25  and the protective cover  32 . The sheets  25  and the protective cover  32  are supplied to the folding module  34 . 
     The folding module  34  includes a quadrilateral pallet  62 , guide ridges  63  and a folding arm  64 . The quadrilateral pallet  62  supports the sheets  25  and the protective cover  32  placed thereon. The guide ridges  63  regulate three edges of the sheets  25  and the protective cover  32  on the quadrilateral pallet  62 . The folding arm  64  folds the protective cover  32  to squeeze the sheets  25 . The folding arm  64  includes an arm portion  65  and a folding pad  66 . The arm portion  65  has substantially a channel shape, and has one end rod supported on a lateral wall of the quadrilateral pallet  62  in a rotatable manner. The folding pad  66  is a suction pad secured to a remaining end rod of the arm portion  65 . The arm portion  65  is rotatable between a first position of the phantom line and a second position of the solid line. When the arm portion  65  rotates from the first position to the second position, the folding pad  66  pushes the protective cover  32  and folds the same to wrap the sheets  25 . 
     A covered sheet stack  67  is created by inserting the sheets  25  in the protective cover  32 . In  FIG. 8 , a retention mechanism  69  includes a retention pad  68  for keeping the protective cover  32  closed by contacting an upper surface of the covered sheet stack  67 . In feeding the covered sheet stack  67 , plates having the guide ridges  63  are retracted to the inside of the quadrilateral pallet  62 . 
     The pre-bending module  33  and the folding module  34  have the pallet or base plate having a common size determined in consideration of the expected maximum size of an X-ray film. Each of the modules can be added, removed or exchanged easily by retention with bolts. In the general-purpose robots in the sheet handling module  30  and the cover handling module  31 , the sheet chuck  44  and the cover suction pads  55  can be exchanged for each of types of the products. Thus, various types and sizes of the products can be produced. 
     Control units are separately associated with respectively the modules included in the covered sheet stack producing device  4 . However, the general-purpose robots in the sheet handling module  30  and the cover handling module  31  are controlled in a harmonized manner. The main control unit for the producing system is provided. The separate control units of the modules in the covered sheet stack producing device  4  are connected to the main control unit, and receive signals for a start and stop of operation, and command of speed. 
     The bag packaging machine  5  includes a stack feeding module  71 , a bag-forming/inserting module  72  and a package finishing module  73 . The stack feeding module  71  feeds the covered sheet stack  67  from the covered sheet stack producing device  4  toward a downstream side. The bag-forming/inserting module  72  packages the covered sheet stack  67  according to the pillow packaging. The stack feeding module  71  consists of a conveyor belt, and sends the covered sheet stack  67  to the bag-forming/inserting module  72 . Note that the stack feeding module  71 , instead of the conveyor belt, may include a chain having plural feeding claws. 
     In  FIGS. 8 and 9 , light-shielding bag material  75  consists of film material, which includes a support of a plastic film and a layer of an aluminum foil overlaid thereon. The bag-forming/inserting module  72  forms the light-shielding bag material  75  into a tubular shape, and also wraps the covered sheet stack  67  in the light-shielding bag material  75 . A juncture sealer of the bag-forming/inserting module  72  welds juncture facets  76   d  of the light-shielding bag material  75  to one another by heat and pressure. A cross sealer welds and closes front and rear flaps of a tubular portion of the light-shielding bag material  75 , at the same time as those flaps are cut. A packaging bag  76  is provided, from which air is removed by an air removing pipe. Finally, the covered sheet stack  67  is enclosed in the packaging bag  76  in a tightly packaged manner. 
     The package finishing module  73  includes a flap folding mechanism of a general-purpose type. A corner of a rear flap  76   a  of the packaging bag  76  is grasped by a robot hand which is disposed in the package finishing module  73  and secured to a robot being movable straight. The robot hand applies tension to the rear flap  76   a  in two directions, and folds it without creating wrinkles. A front flap  76   b  of the packaging bag  76  is also folded. The rear and front flaps  76   a  and  76   b  are retained by a retention mechanism contacting an upper surface of the packaging bag  76 . Finally, a sticker  78  is attached to the rear and front flaps  76   a  and  76   b  to secure those to the packaging bag  76 . 
     The stack feeding, bag-forming/inserting, and package finishing modules  71 – 73  have a pallet or base plate having a common size determined in consideration of the expected maximum size of an X-ray film. Each of the modules can be added, removed or exchanged easily by retention with bolts. Control units are associated with respectively the stack feeding, bag-forming/inserting, and package finishing modules  71 – 73  in the bag packaging machine  5  in a separate manner. The separate control units are connected to the main control unit, and receive signals for a start and stop of operation, and command of speed. 
     The box packaging machine  6  includes a box forming module  96 , a box inserting module  80  and a cardboard caser. The box forming module  96  consists of a general-purpose robot similar to that of the cover handling module  31  described above. See  FIG. 10 . A folding station is located in the box forming module  96 . A blank sheet  83  is handled by the general-purpose robot. The folding station folds a target end portion of the blank sheet  83 , so that an outer box  82  with a decorative pattern is created. Also, a hot-melt gun  84  is disposed in the folding station, ejects hot-melt adhesive agent at a suitable amount, and attaches portions of a juncture of the outer box  82 . 
     The box inserting module  80  inserts a guide plate into the outer box  82 , to place the packaging bag  76  having the covered sheet stack  67  into the outer box  82 . Then a lid of the outer box  82  is closed. A sticker  86  is attached to the outer box  82  by the box inserting module  80 . In the box inserting module  80 , information such as a lot number is printed to the outer box  82 . An image processor inspects the outer box  82  for appearance to check the attached state of the sticker  86 , the printed state and the like. 
     The cardboard caser consists of a multi-joint robot of a general-purpose type to handle the outer box  82 , and inserts five outer boxes  82  to a single outer packaging cardboard box. 
     The box forming module  96 , the box inserting module  80  and the cardboard caser have a pallet or base plate having a common size determined in consideration of the expected maximum size of an X-ray film. Each of the modules can be added, removed or exchanged easily by retention with bolts. Control units are associated with respectively the box forming module  96 , the box inserting module  80  and the cardboard caser in a separate manner. The separate control units are connected to the main control unit, and receive signals for a start and stop of operation, and command of speed. 
     The operation of the above embodiment is described now. In  FIG. 1 , the web  8  of X-ray film with a large width is set in the slitting device  2 , and slitted by the slitting blades  9  at the width of the product. The continuous sheet  10  obtained by the slitting is wound about the spool  12  set in the continuous sheet container  11 . 
     The continuous sheet container  11  containing the continuous sheet  10  is removed from the slitting device  2  and set into the cutting/stacking device  3 . Then the continuous sheet  10  is drawn from the continuous sheet container  11  in a state with tension applied by the regular tension control mechanism. The continuous sheet  10  is unwound, and uncurled by operation of the heating roller  19  of the decurler module  15  and the cooler. 
     The continuous sheet  10  after being uncurled is fed by the suction drum  22  in the cutter module  16  at a regular rate, and cut by the rotary oscillation cutter  23  synchronized with the suction drum  22 . Thus, the sheets  25  in  FIG. 2  are obtained. The sheets  25  are fed by the conveyor of the stacker module  17 , and stacked in the stackers  27  and  28 . 
     In  FIG. 3 , the sheet handling module  30  inserts the chuck plates  45   c  and  45   d  into the grooves  27   e  and  27   f  formed in the quadrilateral pallet  27   a  of the stacker  27 . Then the chuck plates  45   a  and  45   b  are moved down, to squeeze the sheets  25  by cooperation with the chuck plates  45   c  and  45   d . The joints of the sheet moving robot arm  36  are actuated, to pick up the sheets  25  away from the stacker  27 . 
     At the same time as the sheets  25  are produced and stacked, the protective cover  32  is pre-bent. In  FIG. 4 , the cover suction pads  55  in the cover handling module  31  suck and retain the protective cover  32  cut and stacked in a shape of a trapezoid. 
     In  FIG. 5 , the protective cover  32  is fed to the pre-bending module  33 , to insert the target end portion of the protective cover  32  between the base  59  and the bender plate  60 . A moving mechanism (not shown) moves down the bender plate  60 , to pre-bend the protective cover  32  by squeezing with the base  59 . The cover handling module  31  sets the target end portion of the protective cover  32  to the pre-bending module  33  one piece after another, until all the prepared pieces of the protective cover  32  are pre-bent finally. 
     In  FIG. 6 , the protective cover  32  being pre-bent is placed by the cover handling module  31  on to an upper surface of the sheets  25  grasped by the sheet chuck  44  of the sheet handling module  30 . In the sheet handling module  30  provided with the protective cover  32 , the sheet chuck  44  squeezes the sheets  25  and the protective cover  32 . In  FIG. 7 , the rotational pivot  40  turns the sheet chuck  44  to orient the sheets  25  in a state where the protective cover  32  lies on an upper surface of the sheets  25 . After the turn, the sheets  25  and the protective cover  32  are supplied to the folding module  34 . 
     In the folding module  34 , the arm portion  65  rotates from the position of the phantom line to the position of the solid line. The folding pad  66  pushes the protective cover  32  to fold the pre-bent end portion tightly to the surface of the sheets  25 . The covered sheet stack  67  is obtained as combination of the protective cover  32  and the sheets  25 . In  FIG. 8 , the retention pad  68  contacts the upper surface of the covered sheet stack  67  and keeps the protective cover  32  closed. The retention mechanism  69  feeds the covered sheet stack  67  to the bag packaging machine  5 . Before feeding the covered sheet stack  67 , the plates with the guide ridges  63  are retracted to the inside of the quadrilateral pallet  62 . 
     In the bag packaging machine  5  provided with the covered sheet stack  67  by the covered sheet stack producing device  4 , the stack feeding module  71  feeds the covered sheet stack  67  toward the bag-forming/inserting module  72 . In  FIGS. 8 and 9 , the bag-forming/inserting module  72  forms the light-shielding bag material  75  into a tubular shape, the light-shielding bag material  75  including a plastic film overlaid with an aluminum layer. The bag-forming/inserting module  72  causes the light-shielding bag material  75  to wrap the covered sheet stack  67 , and simultaneously causes a juncture sealer to weld and close the juncture facets  76   d  of the light-shielding bag material  75  by heat and pressure. Then front and rear ends of the light-shielding bag material  75  are welded and closed by a cross sealer with heat and pressure. Air is sucked out and removed from the packaging bag by an air removing pipe, to package the covered sheet stack  67  in the packaging bag  76  in a tightly sealed state. 
     In the package finishing module  73 , a robot hand grasps a corner of the rear flap  76   a  of the packaging bag  76 . The robot hand applies tension to the rear flap  76   a  in two directions, while the flap folding mechanism of a general-purpose type folds it without creating wrinkles. Also, the front flap  76   b  of the packaging bag  76  is folded. The retention mechanism contacts the upper surface of the packaging bag  76  and keeps the rear and front flaps  76   a  and  76   b  closed. Then the sticker  78  is attached to secure the rear and front flaps  76   a  and  76   b  to the packaging bag  76 . 
     In the box packaging machine  6 , the box forming module  96  having the general-purpose robot bends the blank sheet  83 . See  FIG. 10 . After bending, the hot-melt gun  84  attaches portions of the blank sheet  83 , to obtain the outer box  82 . 
     The box inserting module  80  inserts the guide plate into the outer box  82 , and loads it with the packaging bag  76  containing the covered sheet stack  67 . Then the lid of the outer box  82  is closed. The sticker  86  is attached. In the box inserting module  80 , the lot number and the like are printed to the outer box  82 . The image processor is used to inspect the attached state of the sticker, the printed state and the like. 
     The outer box  82  containing the packaging bag  76  is handled by the cardboard caser, and inserted in an outer packaging cardboard box, which is provided with five outer boxes  82 . 
     In the X-ray film producing system, the slitting device  2 , the cutting/stacking device  3 , the covered sheet stack producing device  4 , the bag packaging machine  5  and the box packaging machine  6  are connected in series, and are balanced in relation to the line capacity balance. Accordingly, it is unnecessary to keep a space for reservation of the material. No complicated administration of materials is required. Any of the modules included in the system has a pallet or base plate having a common size determined in consideration of the expected maximum size of an X-ray film. Each of the modules can be added, removed or exchanged easily according to an amount of production. 
     In the above embodiment, the sheet package producing system is used in the manufacture of X-ray films. However, sheets to be packaged according to the invention may be photo films, heat sensitive film, photosensitive heat developable films, PPC paper sheets, and any other suitable material of a shape of a film, sheet or plate. 
     Although the present invention has been fully described by way of the preferred embodiments thereof with reference to the accompanying drawings, various changes and modifications will be apparent to those having skill in this field. Therefore, unless otherwise these changes and modifications depart from the scope of the present invention, they should be construed as included therein.