Patent Publication Number: US-11046467-B2

Title: Packaging apparatus

Description:
TECHNICAL FIELD 
     The present disclosure relates to a packaging apparatus. 
     BACKGROUND 
     As a conventional packaging apparatus, an apparatus described in Japanese Unexamined Patent Publication No. 2001-106202, for example, is known. This packaging apparatus described in Japanese Unexamined Patent Publication No. 2001-106202 includes: a delivering unit configured to deliver a film from a film roll when the film roll is newly set; first and second feeder portions configured to hold the film delivered from the delivering unit with first and second clamp units, respectively, to deliver the film in a longitudinal direction; a moving unit configured to change relative distance between the first and the second feeder portions in a film-width direction; and a controller configured to cause the first and the second feeder portions to deliver the film in a film longitudinal direction while causing the moving unit to increase the relative distance between the first and the second feeder portions in the film-width direction. 
     SUMMARY 
     In the conventional packaging apparatus, the film delivered by the delivering unit is held by the first clamp unit and the second clamp unit, and the first feeder portion and the second feeder portion convey the film. At this time, for example, when the film is adhesive, the film may adhere to the feeder portions, which may result in delay in feeding of the film and formation of a bundle (heap) of films inside the feeder portions. In this case, a problem may occur in that, for example, the film jams in the feeder portions and load is accordingly applied to a component such as a drive unit configured to drive the feeder portions. 
     One aspect of the present disclosure aims to provide a packaging apparatus that can prevent occurrence of such a problem due to film jam. 
     A packaging apparatus according to one aspect of the present disclosure is a packaging apparatus configured to package an object to be packaged by covering the object to be packaged with a film that is stretched while a peripheral portion of the film is being held. The packaging apparatus includes: a delivering unit configured to deliver the film from a film roll onto which the film is wound; a first conveying unit including a first clamp unit and a first feeder portion, the first clamp unit being configured to clamp the film delivered from the delivering unit, the first feeder portion being configured to convey the film clamped by the first clamp unit in a first direction that is a direction in which the film is paid out; a second conveying unit including a second clamp unit and a second feeder portion, the second clamp unit being configured to clamp the film delivered from the delivering unit, the second feeder portion being configured to convey the film clamped by the second clamp unit in the first direction; a first moving unit configured to move the first conveying unit in a second direction that is a width direction of the film, a second moving unit configured to move the second conveying unit in the second direction; and a controller configured to control operation of the first conveying unit, the second conveying unit, the first moving unit, and the second moving unit. When the film is loaded onto the first conveying unit and the second conveying unit, the controller causes the first clamp unit to clamp the film delivered by the delivering unit and causes the first feeder portion to convey the film. Simultaneously, while causing the second clamp unit to open or the second clamp unit to intermittently clamp the film delivered by the delivering unit, the controller causes the second feeder portion to convey the film and also causes the second conveying unit to move in a direction separating from the first conveying unit and, when the second conveying unit reaches a predetermined position in the second direction, causes the second clamp unit to clamp the film. 
     In the packaging apparatus according to the one aspect of the present disclosure, while causing the second clamp unit to open or the second clamp unit to intermittently clamp the film delivered by the delivering unit, the controller causes the second feeder portion to convey the film and, when the second conveying unit reaches the predetermined position (predetermined position in the film-width direction) in the second direction, causes the second clamp unit to clamp the film. Accordingly, until the second conveying unit reaches the predetermined position in the second direction, the film is not clamped by the second clamp unit or is intermittently clamped by the second clamp unit. This can prevent the film from adhering to the second feeder portion at least until the predetermined position is reached, which makes it possible to prevent formation of a bundle of films inside the second feeder portion. Thus, the packaging apparatus can prevent occurrence of a problem due to film jam. 
     In one embodiment, the packaging apparatus may further include a cutting unit configured to cut the film between the delivering unit and the first and the second conveying units, in which the controller may cause the cutting unit to cut the film and then cause the first clamp unit and the second clamp unit to release the clamped film. This enables an operator to easily remove the cut film. 
     In one embodiment, the predetermined position may be a position at a length equal to or greater than one half of film width in the width direction of the film. This enables the film to be further prevented from adhering to the feeders. 
     According to one aspect of the present disclosure, occurrence of a problem due to film jam can be prevented. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is an external perspective view illustrating a packaging apparatus according to one embodiment; 
         FIG. 2  is a schematic front view illustrating the inside of the packaging apparatus in  FIG. 1 ; 
         FIG. 3  is a schematic cross-sectional view taken along the line III-III, viewed in the direction of the arrows in  FIG. 2 ; 
         FIG. 4  is a schematic plan view of the packaging apparatus; 
         FIG. 5  is a block diagram illustrating a configuration of the packaging apparatus in  FIG. 1 ; 
         FIG. 6A  is a perspective view illustrating a film delivering mechanism; 
         FIG. 6B  is a perspective view illustrating the film delivering mechanism; 
         FIG. 6C  is a perspective view illustrating the film delivering mechanism; 
         FIG. 7  is a diagram illustrating a loading unit; 
         FIG. 8  is a perspective view illustrating a film delivering mechanism, a cutter mechanism, and a film conveyance mechanism; 
         FIG. 9A  is a diagram illustrating a first feeder unit (second feeder unit); 
         FIG. 9B  is a diagram illustrating the first feeder unit (second feeder unit); 
         FIG. 9C  is a diagram illustrating the first feeder unit (second feeder unit); 
         FIG. 10A  is a diagram illustrating a loading operation; 
         FIG. 10B  is a diagram illustrating a loading operation; 
         FIG. 11A  is a diagram illustrating a loading operation; 
         FIG. 11B  is a diagram illustrating a loading operation; 
         FIG. 12A  is a diagram illustrating a loading operation; and 
         FIG. 12B  is a diagram illustrating a loading operation. 
     
    
    
     DETAILED DESCRIPTION 
     One embodiment will now be described with reference to the drawings. In the description of the drawings, like elements are designated by like numerals, and duplicate description is omitted. 
     As depicted in  FIG. 1  to  FIG. 3 , a packaging apparatus  1  is an apparatus configured to film-package an object (object to be packaged) W including a product G such as a food product and a tray T on which the product G is placed. The packaging apparatus  1  packages an object W with a film F by pushing up the object W against a film F that is tensionally held and folding peripheral portions of the film F over the bottom side of the tray T. The packaging apparatus  1  includes a measuring function and a price-tagging function of affixing labels in addition to the film-packaging function. 
     The packaging apparatus  1  includes a measuring carrying-in mechanism  2 , a packaging station  3 , a roll holding mechanism  4 , a film delivering mechanism (delivering unit)  5 , a film conveyance mechanism  6 , a cutter mechanism (cutting unit)  7 , a seal mechanism  8 , a label printer LP, a label issuing device LI, and a control unit  9 . The respective mechanisms included in the packaging apparatus  1  are accommodated in a body  1   a  and a casing  1   b  of the packaging apparatus  1 . The casing  1   b  is attached to a side portion of the body  1   a.    
     In the description of the present embodiment, “right and left” mean right and left when facing the front of the body  1   a  of the packaging apparatus  1 . The front side of the packaging apparatus  1  in the front-back direction is called “near side”, and the side opposite thereto is called “far side”. The expression “film F 1 , F 2 ” means either one optionally selected from a film F 1  and a film F 2 , and is also simply called a film F. The expression “film roll R 1 , R 2 ” means either one optionally selected from a film roll R 1  and a film roll R 2 . The terms “upstream” and “downstream” mean upstream of the film F in the conveying direction and downstream thereof in the conveying direction, respectively. 
     As depicted in  FIG. 3 , the measuring carrying-in mechanism  2  includes a measuring scale  2   a , a carrying-in belt  2   b , and a measuring vessel  12 . The measuring scale  2   a  measures the weight of an object W placed on the measuring vessel  12 , and outputs information on the weight of the object W to the control unit  9 . The carrying-in belt  2   b  is looped over a pair of rollers. The carrying-in belt  2   b  is provided with a conveying bar  13  for conveying the object W. The conveying bar  13  moves toward the far side while being driven by the carrying-in belt  2   b , and pushes the object W toward the far side. The conveying bar  13  extends along the width direction of the measuring vessel  12 , and is positioned on the near side of the measuring vessel  12  in an initial position. The measuring vessel  12  is a tray having a shape of a rectangular shallow vessel on which the object W is placed. 
     The packaging station  3  is a space formed in the body  1   a . The packaging station  3  is a space in which a series of film-packaging processes are performed on an object W the weight of which is measured by the measuring carrying-in mechanism  2 . In the packaging station  3 , a lifter mechanism  30  and a folding mechanism  37  are disposed. 
     The lifter mechanism  30  is provided in a lower portion of the packaging station  3 . The lifter mechanism  30  receives the bottom surface of a tray T with a plurality of support members  33 , and causes a electric ball screw mechanism  34  to move upward a support base  31  fixed to the support members  33 . Consequently, the lifter mechanism  30  holds the bottom surface of the tray T and moves the object W upward. The lifter mechanism  30  pushes up the object W against a film (stretch film) F 1 , F 2  that is tensionally held by the film conveyance mechanism  6 . 
     The folding mechanism  37  folds the periphery of the film F 1 , F 2  over the bottom side of the object W (i.e., the bottom side of the tray T) pushed up by the lifter mechanism  30  to cover the object W with the film F 1 , F 2 . The folding mechanism  37  folds both ends of the film F 1 , F 2  in the film conveying direction over the bottom side of the tray T with right and left folding plates  76  and  77 . The folding mechanism  37  folds a side portion of the film F 1 , F 2  on the far side in the width direction over the bottom side of the tray T with a rear folding plate  78 . When the tray T is discharged toward the seal mechanism  8  by a discharging pusher  79   a , the folding mechanism  37  folds a side portion of the film F 1 , F 2  on the near side in the width direction over the bottom side of the tray T with a front folding bar  79 . 
     The roll holding mechanism  4  is disposed in the casing  1   b  as depicted in  FIG. 1  and  FIG. 2 . The roll holding mechanism  4  is configured to hold two film rolls R 1  and R 2  that are of the same type or of different types. On the film rolls R 1  and R 2 , films F 1  and F 2  having a predetermined width are wound multiple times, respectively. 
     As depicted in  FIG. 2 , the roll holding mechanism  4  includes an upper-roll holding unit  41  configured to hold the film roll R 1 , a lower-roll holding unit  42  configured to hold the film roll R 2 , and a roll drive unit  43  configured to cause the upper-roll holding unit  41  and the lower-roll holding unit  42  to selectively rotate to pay out the film F 1  or the film F 2  from either one of the film rolls R 1  and R 2 . 
     The film delivering mechanism  5  is a mechanism configured to transfer the film F 1  pulled out from the film roll R 1  or the film F 2  pulled out from the film roll R 2  to a pair of feeder units  61  and  62  of the film conveyance mechanism  6 . The film delivering mechanism  5  is disposed in the casing  1   b.    
     As depicted in  FIG. 6A  to  FIG. 6C , the film delivering mechanism  5  includes a loading-unit movement frame  51 , a loading unit  70 , and a loading-unit drive motor  52  (see  FIG. 2 ). 
     The loading-unit movement frame  51  is disposed in an upper area in the casing  1   b  (above the roll holding mechanism  4 ). The loading-unit movement frame  51  rotatably supports a loading-unit rotation shaft  70   a  described later. The loading-unit movement frame  51  is provided so as to be movable in the horizontal direction by a link mechanism. Specifically, the loading-unit movement frame  51  moves between a first position farthest from the film conveyance mechanism  6  and a second position closest to the film conveyance mechanism  6 . 
     The loading unit  70  is attached to the loading-unit movement frame  51 . The loading unit  70  includes a first grasping unit  71 , a second grasping unit  72 , and the loading-unit rotation shaft  70   a.    
     As depicted in  FIG. 7 , the first grasping unit  71  and the second grasping unit  72  are attached to the loading-unit rotation shaft  70   a . The first grasping unit  71  and the second grasping unit  72  are disposed at positions that are bilaterally symmetrical with respect to a reference line L. The reference line L is a straight line virtually extending from the center of the loading-unit rotation shaft  70   a  along the height direction of the loading-unit movement frame  51 . The first grasping unit  71  and the second grasping unit  72  form a V shape. 
     The first grasping unit  71  includes two plate members  71   a  and  71   b  and a one-way roller  71   c . One end of the plate member  71   a  and one end of the plate member  71   b  are coupled together by a hinge (not depicted). As depicted in  FIG. 4 , the plate member  71   b  is provided so as to pivot about the hinge with respect to the plate member  71   a  and to be openable and closable with respect to the plate member  71   a . The one-way roller  71   c  is a roller configured to allow rotation in only one direction (arrow A 1  direction in  FIG. 7 ). The one-way roller  71   c  is provided in plurality along the longitudinal direction (film-width direction) of the plate member  71   a . The one-way rollers  71   c  hold a film F 1  sandwiched between the plate member  71   a  and the plate member  71   b  so that the film F 1  does not fall off downward. 
     As depicted in  FIG. 7 , the second grasping unit  72  includes two plate members  72   a  and  72   b  and a one-way roller  72   c . One end of the plate member  72   a  and one end of the plate member  72   b  are coupled by a hinge (not depicted). As depicted in  FIG. 4 , the plate member  72   b  is provided so as to pivot about the hinge with respect to the plate member  72   a  and to be openable and closable with respect to the plate member  72   a . The one-way roller  72   c  is a roller configured to allow rotation in only one direction (arrow A 1  direction in  FIG. 7 ). The one-way roller  72   c  is provided in plurality along the longitudinal direction (film-width direction) of the plate member  72   a . The one-way rollers  72   c  hold a film F 2  sandwiched between the plate member  72   a  and the plate member  72   b  so that the film F 2  does not fall off downward. 
     The first grasping unit  71  and the second grasping unit  72  are used in a switched manner depending on the type of the film (the film F 1  or the film F 2 ). The first grasping unit  71  is a unit configured to grasp the film F 1 . The second grasping unit  72  is a unit configured to grasp the film F 2 . The first grasping unit  71  and the second grasping unit  72  each have a predetermined length in the depth direction of the casing  1   b  so that the film F 1 , F 2  can be delivered. 
     The loading-unit rotation shaft  70   a  is rotatably supported by the loading-unit movement frame  51 . The loading-unit rotation shaft  70   a  is driven by the loading-unit drive motor  52  (see  FIG. 2 ). By changing the rotation angle of the loading-unit rotation shaft  70   a , the loading unit  70  changes attitudes as depicted in  FIG. 6A  to  FIG. 6C . 
     As depicted in  FIG. 6A , when the loading unit  70  causes the first grasping unit  71  to grasp the film F 1  or causes the second grasping unit  72  to grasp the film F 2 , the first grasping unit  71  and the second grasping unit  72  are positioned symmetrically with respect to the reference line L (loading position). 
     As depicted in  FIG. 6B , when the loading unit  70  causes the first grasping unit  71  to transfer (deliver) the film F 1  to the film conveyance mechanism  6 , the first grasping unit  71  is tilted so as to be parallel to the horizontal plane (feeding position). Accordingly, the film F 1  is delivered horizontally from the distal end of the first grasping unit  71  to the film conveyance mechanism  6 . 
     As depicted in  FIG. 6C , when the loading unit  70  causes the second grasping unit  72  to transfer the film F 2  to the film conveyance mechanism  6 , the second grasping unit  72  is tilted so as to be parallel to the horizontal plane (feeding position). Accordingly, the film F 2  is delivered horizontally from the distal end of the second grasping unit  72  to the film conveyance mechanism  6 . 
     As depicted in  FIG. 2  and  FIG. 3 , the film conveyance mechanism  6  receives the film F from the film delivering mechanism  5  and conveys the film F to the packaging station  3 . The film conveyance mechanism  6  also tensionally holds the film F received from the film delivering mechanism  5  in a central area of the packaging station  3 . The film conveyance mechanism  6  includes the first feeder unit (first conveying unit)  61 , the second feeder unit (second conveying unit)  62 , a first feeder moving unit (first moving unit)  63 , a second feeder moving unit (second moving unit)  64 , and a feeder driving unit  65 . 
     As depicted in  FIG. 4 , the first feeder unit  61  is disposed on the near side in the front-back direction of the packaging apparatus  1 . The second feeder unit  62  is disposed on the far side with respect to the first feeder unit  61  in the front-back direction of the packaging apparatus  1 . The first feeder unit  61  and the second feeder unit  62  are disposed along the longitudinal direction of the film F. The first feeder unit  61  and the second feeder unit  62  are driven by the feeder driving unit  65  to convey the film F. 
     In both end portions of the first feeder unit  61  and the second feeder unit  62  in the longitudinal direction, as depicted in  FIG. 4 , slide shafts  66  and  67  extending in the width direction of the film F are provided. The slide shafts  66  and  67  support the first feeder unit  61  and the second feeder unit  62 . The first feeder unit  61  and the second feeder unit  62  are respectively driven by the first feeder moving unit  63  and the second feeder moving unit  64  to move along the slide shafts  66  and  67  in the film-width direction. 
     The first feeder unit  61  and the second feeder unit  62  have the same configuration. The following describes the configuration of the first feeder unit  61  as one example in detail with reference to  FIG. 8  and  FIG. 9A  to  FIG. 9C . 
     The first feeder unit  61  includes an introducing unit (first clamp unit)  22 A, a lower belt  23 A, an upper belt  24 A, an upstream clamp  25 A, a midstream clamp  26 A, and a downstream clamp  27 A. These respective components are supported by a supporting frame  21 . The lower belt  23 A and the upper belt  24 A constitute a first feeder portion configured to convey the film F. 
     The introducing unit  22 A clamps the film F delivered from the film delivering mechanism  5  to introduce the film F between the lower belt  23 A and the upper belt  24 A. The introducing unit  22 A is disposed upstream of the first feeder unit  61 , that is, near the loading unit  70  (see  FIG. 8 ). As depicted in  FIG. 9C , the introducing unit  22 A is provided in a position overlapping the lower belt  23 A. 
     The introducing unit  22 A includes a body portion  22   c  provided swingably about an introducing-unit pivot shaft  22   b . The introducing-unit pivot shaft  22   b  is provided to the downstream end of the body portion  22   c . The introducing-unit pivot shaft  22   b  is supported by the frame  21 . The body portion  22   c  swings upon actuation of a solenoid (not depicted). Specifically, upon actuation of the solenoid, the body portion  22   c  swings within a range between a lower position at which the upstream end of the body portion  22   c  is close to the lower belt  23 A and an upper position at which the upstream end of the body portion  22   c  is apart from the lower belt  23 A. The introducing unit  22 A clamps the film F when the body portion  22   c  is in the lower position, and does not clamp the film F when the body portion  22   c  is in the upper position. 
     To the other end (end close to the film delivering mechanism  5 ) of the body portion  22   c , an introducing pulley  22   a  is rotatably provided. Over the introducing pulley  22   a , the upper belt  24 A is looped. 
     The lower belt  23 A comes into contact with the film F from below. The lower belt  23 A is looped over a plurality of pulleys as depicted in  FIG. 9B . These pulleys include a pulley  21   b  and a pulley  21   c . The pulley  21   b  is disposed upstream in the conveying direction of the film F. The pulley  21   c  is disposed downstream in the conveying direction of the film F. The pulley  21   c  is rotated by a drive motor. The pulley  21   b  is driven by the rotation of the pulley  21   c . Driven by the pulley  21   c  rotated by the drive motor, the lower belt  23 A of the first feeder unit  61  moves. 
     The upper belt  24 A is looped over a plurality of pulleys as depicted in  FIG. 9B . These pulleys include the introducing pulley  22   a  of the introducing unit  22 A and a pulley  24   a . The pulley  24   a  is disposed downstream in the conveying direction of the film F. The pulley  24   a  is rotated by the drive motor that rotates the pulley  21   c . Thus, the upper belt  24 A is driven together with the lower belt  23 A. With the above-described configuration, the first feeder unit  61  draws in the film between the upper belt  24 A and the lower belt  23 A, and conveys the film F in the longitudinal direction (first direction) of the film F in which the film F is paid out. 
     As depicted in  FIG. 9C , the upstream clamp  25 A is disposed upstream in the conveying direction of the film. The downstream clamp  27 A is disposed downstream in the conveying direction of the film. The midstream clamp  26 A is disposed between the upstream clamp  25 A and the downstream clamp  27 A. The respective clamps  25 A to  27 A are disposed in positions displaced from the belts  23  and  24 . Specifically, the respective clamps  25 A to  27 A are disposed on the inner side of the belts  23 A and  24 A in the width direction of the film F. Below the respective clamps  25 A to  27 A, a band plate  21   a  is disposed. 
     Each of the clamps  25 A to  27 A operates in accordance with ON/OFF switching of a solenoid (not depicted). Specifically, each of the clamps  25 A to  27 A clamps the film F and releases the film F in accordance with ON/OFF switching of the corresponding solenoid. Each of the clamps  25 A to  27 A comes into contact with the upper surface of the film F 1 , F 2  to apply a downward force thereto when the corresponding solenoid is ON. Accordingly, the film F is clamped between the band plate  21   a  and each of the clamps  25 A to  27 A. Each of the clamps  25 A to  27 A releases the clamped film F when the corresponding solenoid is OFF. Each solenoid can be switched ON at a predetermined timing. 
     The second feeder unit  62  has the same configuration as that of the first feeder unit  61 . Specifically, the second feeder unit  62  includes an introducing unit (second clamp unit)  22 B, a lower belt  23 B, an upper belt  24 B, an upstream clamp  25 B, a midstream clamp  26 B, and a downstream clamp  27 B. These respective components are supported by the supporting frame  21 . The lower belt  23 B and the upper belt  24 B constitute a second feeder portion configured to convey the film F. 
     The first feeder moving unit  63  is attached below the first feeder unit  61 . As depicted in  FIG. 3 , the first feeder moving unit  63  includes a drive motor  63   a  and a belt  63   b . The second feeder moving unit  64  is attached below the second feeder unit  62 . As depicted in  FIG. 3 , the second feeder moving unit  64  includes a drive motor  64   a  and a belt  64   b.    
     The first feeder moving unit  63  causes the drive motor  63   a  to drive the belt  63   b , thereby moving the first feeder unit  61  along the slide shafts  66  and  67  in the width direction (second direction) of the film F. The second feeder moving unit  64  causes the drive motor  64   a  to drive the belt  64   b , thereby moving the second feeder unit  62  along the slide shafts  66  and  67  in the width direction of the film F. 
     As depicted in  FIG. 2 , after the film delivering mechanism  5  transfers the film F to the film conveyance mechanism  6 , the cutter mechanism  7  cuts the film F stretched between the film delivering mechanism  5  and the film conveyance mechanism  6 . After the film conveyance mechanism  6  conveys the film F of a predetermined length, the cutter mechanism  7  cuts the film F stretched between the film delivering mechanism  5  and the film conveyance mechanism  6 . The cutter mechanism  7  is disposed between the film delivering mechanism  5  and the film conveyance mechanism  6 , and includes a cutting blade  7   a  that is longer than the film width of the film F. The cutting blade  7   a  is moved vertically by an actuator. 
     The seal mechanism  8  heat-seals the film F that is folded by the folding mechanism  37 . The seal mechanism  8  includes a conveying roller and heating roller, and heat-seals an object W pushed out by the discharging pusher  79   a  while conveying the object W by the conveying roller and the heating roller. The seal mechanism  8  discharges the object W thus packaged toward a discharge table  82 . 
     As depicted in  FIG. 1  and  FIG. 5 , the label printer LP prints information about goods on a label. Examples of the information about goods include a product name and price. The label issuing device LI pastes the label printed by the label printer LP on the discharged packaged product. 
     The control unit  9  is a computer disposed in an upper portion of the body  1   a . The control unit  9  controls operation of each mechanism described above. The control unit  9  includes an input/output interface I/O configured to perform signal input and output from and to the outside, a read only memory (ROM) in which a program and information, for example, for performing processes are stored, a random access memory (RAM) configured to temporarily store therein data, a recording medium such as a hard disk drive (HDD), a central processing unit (CPU), and a communication circuit, for example. The control unit  9  implements each function, based on signals output by the CPU, by storing input data in the RAM, loading the program stored in the ROM into the RAM, and executing the program loaded in the RAM. 
     To the control unit  9 , a display panel  16  and an operating portion  17  are connected. The display panel  16  is a touch-panel display, for example, and operation buttons are displayed on the display. With the operating portion  17 , a user performs various operations and inputs. 
     The control unit  9  includes a storage  9   a  and a controller  9   b . In the storage  9   a , various types of data that are predetermined, are input from the display panel  16  or the operating portion  17 , for example, or are transferred from an external device are stored. These various types of data include data on properties (thickness, material, film width, etc.) of a plurality of types of films F, data on unit price data and properties of a plurality of types of products data on properties (size, shape, material, tare weight, etc.) of a plurality of types of trays T. 
     The controller  9   b  controls operation of each mechanism. When the film F is loaded onto the first feeder unit  61  and the second feeder unit  62 , the controller  9   b  causes the introducing unit  22 A to clamp the film F delivered by the film delivering mechanism  5  and causes the lower belt  23 A and the upper belt  24 A to convey the film F. Simultaneously, while causing the introducing unit  22 B to open or the introducing unit  22 B to intermittently clamp the film F delivered by the film delivering mechanism  5 , the controller  9   b  causes the lower belt  23 B and the upper belt  24 B to convey the film F and also causes the second feeder unit  62  to move in the direction separating from the first feeder unit  61  and, when the second feeder unit  62  reaches a predetermined position in the second direction, causes the introducing unit  22 B to clamp the film F. In other words, the controller  9  is a circuit configured to, when the film F is loaded onto the first feeder unit  61  and the second feeder unit  62 , cause the introducing unit  22 A to clamp the film F delivered by the film delivering mechanism  5  and cause the lower belt  23 A and the upper belt  24 A to convey the film F, and simultaneously, while causing the introducing unit  22 B to open or the introducing unit  22 B to intermittently clamp the film F delivered by the film delivering mechanism  5 , cause the lower belt  23 B and the upper belt  24 B to convey the film F and also cause the second feeder unit  62  to move in the direction separating from the first feeder unit  61  and, when the second feeder unit  62  reaches the predetermined position in the second direction, cause the introducing unit  22 B to clamp the film F. Specific operation of the controller  9   b  will be described later. 
     The control unit  9  thus configured refers to various types of data in the storage  9   a  and, based on the weight and/or the tray size of an object W measured by the measuring carrying-in mechanism  2 , calculates the price of the object W, for example. The control unit  9  controls operation of the label printer LP and the label issuing device LI, and prints the weight or the price of the object W on a label. 
     The following schematically describes packaging operation in the packaging apparatus  1 . 
     In the packaging apparatus  1 , when a user places an object W on the measuring vessel  12  of the measuring carrying-in mechanism  2 , the weight of the object W is measured by the measuring scale  2   a . The object W is pushed out onto the support members  33  of the lifter mechanism  30  by the conveying bar  13 . Meanwhile, the film F is transferred to the film conveyance mechanism  6  by the film delivering mechanism  5 , and the film F is cut by the cutter mechanism  7  into a sheet of rectangular film F. The film F is conveyed to above the lifter mechanism  30  by the feeder units  61  and  62 , and both side portions thereof in the width direction are tensionally held. 
     Against the film F thus tensionally held, the object W is pushed up by the lifter mechanism  30 , and the film F is stretched so as to cover the object W. The periphery of the film F is folded over the lower side of the tray T by the folding mechanism  37 . The object W is pushed out toward the seal mechanism  8  by the discharging pusher  79   a . Subsequently, the film F is heat-sealed by the seal mechanism  8 , and is then discharged onto the discharge table  82 . 
     When a process including label pasting is performed, the price and the weight, for example, of the product G calculated based on the measured value are printed on a label by the label printer LP, and this label is pasted on the film F by the label issuing device LI. 
     The following describes loading operation in the packaging apparatus  1  with reference to  FIG. 10A  to  FIG. 12B . In the following description, operation of newly setting a film roll R 1  and loading a film F 1  will be described as one example. 
     In the packaging apparatus  1 , when a film set button (not depicted) is depressed by an operator, the controller  9   b  causes the loading-unit drive motor  52  of the film delivering mechanism  5  to drive, thereby moving the loading unit  70  to the loading position as depicted in  FIG. 10A . The operator pulls out an end of the film F 1  from the film roll R 1 , and sets the film F 1  into the first grasping unit  71  of the loading unit  70 . Specifically, the operator opens the plate member  71   b  of the first grasping unit  71  with respect to the plate member  71   a  to set the film F 1 . 
     Subsequently, when a film loading button (not depicted) is depressed by the operator, the controller  9   b  causes the loading-unit drive motor  52  to drive, thereby tilting the loading unit  70  in the arrow A 2  direction as depicted in  FIG. 10A  and causing the loading unit  70  to move to the feeding position. Accordingly, as depicted in  FIG. 10B , the first grasping unit  71  becomes parallel to the horizontal plane. The controller  9   b  also causes the loading-unit movement frame  51  to move in the arrow A 3  direction as depicted in  FIG. 10B , so that the loading-unit movement frame  51  is positioned in the second position closer to the film conveyance mechanism  6 . 
     Subsequently, as depicted in  FIG. 11A , the controller  9   b  causes the introducing unit  22 A of the first feeder unit  61  to swing in the arrow  4 A direction, so that the introducing unit  22 A is positioned in the lower position. Accordingly, between the introducing unit  22 A and the lower belt  23 A, the film F 1  grasped by the first grasping unit  71  is clamped. 
     Subsequently, the controller  9   b  causes the drive motor configured to drive the pulley  21   c  of the lower belt  23 A to operate. Accordingly, the first feeder unit  61  introduces the film F 1 , and also conveys the film F 1  downstream while drawing in the film F 1  between the lower belt  23 A and the upper belt  24 A. The controller  9   b  also causes the loading-unit movement frame  51  to move in the arrow A 5  direction as depicted in  FIG. 11A , so that the loading-unit movement frame  51  is positioned in the first position farther from the film conveyance mechanism  6 . 
     The controller  9   b  causes the first feeder unit  61  to convey the film F 1  of the predetermined length, and then switches ON the solenoid of the midstream clamp  26 A, for example. Accordingly, the film F 1  is clamped between the midstream clamp  26 A and the band plate  21   a . The controller  9   b  causes the first feeder unit  61  to further convey the film F 1  with the film F 1  being clamped by the midstream clamp  26 A. Accordingly, the film F 1  stays between the lower belt  23 A and the upper belt  24 A. 
     While the introducing unit  22 B of the second feeder unit  62  is positioned in the upper position, the controller  9   b  causes the drive motor configured to drive the pulley  21   c  of the lower belt  23 B to operate, thereby conveying the film F 1  downstream while drawing in the film F 1  between the lower belt  23 B and the upper belt  24 B without clamping the film F 1 . Herein, the timing at which the second feeder unit  62  starts conveying the film F 1  may be the same as the timing at which the first feeder unit  61  starts conveying the film F 1 , or may be after the first feeder unit  61  has started conveying the film F 1 . 
     The controller  9   b  causes the drive motor  64   a  of the second feeder moving unit  64  to drive, thereby moving the second feeder unit  62  toward the far side (direction separating from the first feeder unit  61 ) from the position depicted in  FIG. 12A  to the position depicted in  FIG. 12B . At this time, when the second feeder unit  62  reaches the position at a length equal to one half of the film width as indicated by the dashed line in  FIG. 12B , the controller  9   b  causes the introducing unit  22 B to be positioned in the lower position. Accordingly, the second feeder unit  62  conveys the film F 1  with the lower belt  23 B and the upper belt  24 B while clamping the film F 1  with the introducing unit  22 B from the position at a length equal to one half of the film width. 
     After the second feeder unit  62  is moved to the end (position depicted in  FIG. 12B ) in the film-width direction, when the film F 1  of the predetermined length is introduced into the second feeder unit  62 , the controller  9   b  causes the cutter mechanism  7  to operate as depicted in  FIG. 11B . Consequently, the film F 1  spread between the film delivering mechanism  5  and the film conveyance mechanism  6  is cut. After the film F 1  is cut, the controller  9   b  causes the introducing unit  22 A of the first feeder unit  61  and the introducing unit  22 B of the second feeder unit  62  to release the clamped film F 2 . This ends the loading process of the film F 1 . 
     As described in the foregoing, in the packaging apparatus  1  according to the present embodiment, when the film F is loaded onto the first feeder unit  61  and the second feeder unit  62 , the controller  9   b  causes the introducing unit  22 A to clamp the film F 1  delivered by the film delivering mechanism  5  and causes the lower belt  23 A and the upper belt  24 A to convey the film F, simultaneously causes the lower belt  23 B and the upper belt  24 B to convey the film F with the introducing unit  22 B being open (without clamping the film F) and also causes the second feeder unit  62  to move in the direction separating from the first feeder unit  61  and, when the second feeder unit  62  reaches the predetermined position in the film-width direction, causes the introducing unit  22 B to clamp the film F. 
     Accordingly, until the second feeder unit  62  reaches the predetermined position in the film-width direction, the film F is not clamped by the introducing unit  22 B. This can prevent the film F from adhering to the lower belt  23 B and the upper belt  24 B at least until the predetermined position is reached, which makes it possible to prevent formation of a bundle of films F inside the lower belt  23 B and the upper belt  24 B. Thus, the packaging apparatus  1  can prevent occurrence of a problem due to film jam. 
     In the present embodiment, the packaging apparatus  1  further includes the cutter mechanism  7  configured to cut the film F between the film delivering mechanism  5  and the first and the second feeder units  61  and  62 . The controller  9   b  causes the cutter mechanism  7  to cut the film F and then causes the introducing unit  22 A and the introducing unit  22 B to release the clamped film F. This enables an operator to easily remove the cut film F. 
     In the present embodiment, when the second feeder unit  62  reaches the position at a length equal to or greater than one half of the film width in the film-width direction, the controller  9   b  causes the introducing unit  22 B to clamp the film F. This enables the film F to be further prevented from adhering to the lower belt  23 B and the upper belt  24 B. 
     The present disclosure is not limited to the above-described embodiment. Although a measuring packaging price-tagging apparatus configured to perform measurement, packaging, and price tagging has been described as the packaging apparatus  1  in the above-described embodiment, the packaging apparatus  1  may be configured not to perform measurement and/or price tagging. 
     In the above-described embodiment, a mode has been described as one example in which the introducing unit  22 B is caused to clamp the film F when the second feeder unit  62  reaches the predetermined position (e.g., the position at a length equal to or greater than one half of the film width) in the film-width direction. However, the controller  9   b  may perform control so as to cause the introducing unit  22 B to intermittently clamp the film F until the second feeder unit  62  reaches the predetermined position in the film-width direction. The expression “to intermittently clamp” means to clamp the film F and release the clamped film F at a certain or uncertain timing. The period of time for which the film F is clamped may be set as appropriate. The predetermined position at which clamping of the film F is continuously started in the introducing unit  22 B may be set based on the design as appropriate. 
     At least part of the above-described embodiment may be optionally combined.