Patent Publication Number: US-2023159206-A1

Title: Packaging apparatus

Description:
BACKGROUND 
     Technical Field 
     The present invention relates to a packaging apparatus. More specifically, the present invention relates to a packaging apparatus that seals, with a film, openings of containers conveyed thereto. 
     Related Art 
     Conventionally, packaging apparatus that seal, with a film, openings of containers conveyed thereto are known. 
     Such packaging apparatus may, as in patent document (JP-A No. H10-203505) for example, be provided with a printer on the conveyance path of the film that seals the openings of the containers, and prints various types of information with the printer on the film while conveying the film. 
     SUMMARY 
     Technical Problem 
     A common problem in packaging apparatus is the demand for improved throughput (the number of containers that can be packaged per unit of time). One conceivable measure for solving this problem is to speedily feed the film to a sealing mechanism that seals, with the film, the openings of the containers. 
     However, in the packaging apparatus of patent document 1 (JP-A No. H10-203505), if the speed at which the film is fed to the sealing mechanism were to be increased, the time usable for printing on the film would become shorter, the printing quality would drop, and the problem of printing errors would become more likely to occur. 
     It is an object of the present invention to provide a packaging apparatus that seals, with a film, openings of containers conveyed thereto, the packaging apparatus being able to inhibit a reduction in printing quality on the film even when the film is fed at a high speed to a sealing mechanism that seals the openings of the containers. 
     Solution to Problem 
     A packaging apparatus pertaining to a first aspect of the invention includes a film conveyance unit, a container conveyance unit, a packaging unit, a printing unit, and a control unit. The film conveyance unit is configured to convey a film. The container conveyance unit is configured to convey a container having an opening. The packaging unit is configured to seal, with the film conveyed thereto by the film conveyance unit, the opening of the container conveyed thereto by the container conveyance unit. The printing unit is disposed upstream of the packaging unit in a conveyance path along which the film F is conveyed by the film conveyance unit. The printing unit is configured to print information in a predetermined position on the film while the film being conveyed by the film conveyance unit. The control unit is configured to control the film conveyance unit, the container conveyance unit, the packaging unit, and the printing unit. The film conveyance unit has an accumulation mechanism. The accumulation mechanism is disposed between the printing unit and the packaging unit in the conveyance path of the film. The accumulation mechanism is configured to temporarily accumulate the film printed with the information. The control unit is configured to control the film conveyance unit so that the accumulation mechanism accumulates the film that is utilized for at least one packaging operation in the packaging unit. 
     In the packaging apparatus of the first aspect, the time in which conveyance of the film is stopped or slowed down on the downstream side of the accumulation mechanism in the conveyance path of the film can be utilized for time for printing on the film. For that reason, in the packaging apparatus of the first aspect, time for printing can be ensured and a high printing quality on the film can be maintained. 
     A packaging apparatus pertaining to a second aspect of the invention is the packaging apparatus of the first aspect, wherein a conveyance speed of the film from the printing unit to the accumulation mechanism is slower than a conveyance speed of the film downstream of the accumulation mechanism. 
     In the packaging apparatus of the second aspect, by virtue of having the accumulation mechanism, it is not necessary to synchronize the printing speed of the printing unit with the conveyance speed of the film on the downstream side of the accumulation mechanism. For that reason, in the packaging apparatus of the second aspect, a high printing quality on the film can be maintained even when the film is fed at a high speed to the printing unit. 
     A packaging apparatus pertaining to a third aspect of the invention is the packaging apparatus of the first aspect or the second aspect, wherein the film conveyance unit is configured to convey the film in the printing unit while stopping conveyance of the film in the packaging unit at least for a predetermined period of time. 
     In the packaging apparatus of the third aspect, by virtue of having the accumulation mechanism, the time in which conveyance of the film is stopped for packaging can be utilized for time for printing on the film by the printing unit. For that reason, in the packaging apparatus of the third aspect, a high printing quality on the film can be maintained. 
     A packaging apparatus pertaining to a fourth aspect of the invention is the packaging apparatus of the third aspect, wherein the packaging unit is configured to collectively seal, with the film, the openings of a plurality of the containers lined up parallel to the conveyance direction of the film in the packaging unit in the one packaging operation. 
     In this packaging apparatus, it becomes necessary to feed a length of the film sufficient for the plural containers for every packaging operation by the packaging unit. For that reason, if the packaging apparatus did not have the accumulation mechanism, it would be necessary to complete printing for the plural containers within, at most, the amount of time from the end of a packaging operation to the start of the next packaging operation. 
     In contrast, because the packaging apparatus of the fourth aspect has the accumulation mechanism, the film can be conveyed and printing can be performed on the film even during execution of the packaging operation, and a high printing quality on the film can be maintained. 
     A packaging apparatus pertaining to a fifth aspect of the invention is the packaging apparatus of any of the first aspect to the fourth aspect, and further includes a changing unit that changes a maximum film length accumulable by the accumulation mechanism. 
     In the packaging apparatus of the fifth aspect, even when the size of the containers, the quantity of the containers packaged at one time by the packaging unit, and/or the positions in which the printing unit prints on the film change, the film can be stopped at an appropriate position that will not affect printing by the printing unit when temporarily stopping conveyance of the film. 
     A packaging apparatus pertaining to a sixth aspect of the invention is the packaging apparatus of any of the first aspect to the fifth aspect, wherein the packaging apparatus is configured to stop a printing operation in the printing unit in a case where the film that is utilized for one packaging operation in the packaging unit is accumulated in the accumulation mechanism. 
     In the packaging apparatus pertaining to the sixth aspect of the invention, the film conveyance unit stands by in a state in which the film that is used for one packaging operation has been accumulated in the accumulation mechanism, so the film printed with the information can be provided without delay to the packaging unit in correspondence with the timing of the operation of the packaging unit. 
     At the same time, the accumulation mechanism does not overly accumulate the film, so the size of the accumulation mechanism can be inhibited from becoming excessively large. 
     Advantageous Effects of Invention 
     In the packaging apparatus of the invention, the time in which conveyance of the film is stopped or slowed down on the downstream side of the accumulation mechanism in the conveyance path of the film can be utilized for time for printing on the film. For that reason, in the packaging apparatus of the invention, time for printing can be ensured and a high printing quality on the film can be maintained. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG.  1    is a schematic configuration diagram of a packaging apparatus pertaining to an embodiment of the invention; 
         FIG.  2    is a control block diagram of the packaging apparatus of  FIG.  1   ; 
         FIG.  3 A  is a diagram for describing the operation of a moving mechanism of the packaging apparatus of  FIG.  1   ; 
         FIG.  3 B  is a diagram for describing the operation of the moving mechanism of the packaging apparatus of  FIG.  1   ; 
         FIG.  3 C  is a diagram for describing the operation of the moving mechanism of the packaging apparatus of  FIG.  1   ; 
         FIG.  3 D  is a diagram for describing the operation of the moving mechanism of the packaging apparatus of  FIG.  1   ; 
         FIG.  4    is a diagram schematically showing a film conveyance device that the packaging apparatus of  FIG.  1    has and configurations in the vicinity of the film conveyance device; 
         FIG.  5    is a flowchart for mainly describing operations by which containers are packaged by the packaging apparatus of  FIG.  1   ; and 
         FIG.  6    is a flowchart for mainly describing the operation of the film conveyance device of the packaging apparatus of  FIG.  1   . 
     
    
    
     DETAILED DESCRIPTION 
     An embodiment of the packaging apparatus pertaining to the invention will be described below with reference to the drawings. It will be noted that the embodiment of the packaging apparatus described below is merely an example and that many changes in form and detail may be made without departing from the spirit and scope of the disclosure as defined in the claims. 
     (1) Overview 
     The overall configuration of a packaging apparatus  1  pertaining to an embodiment of the invention will now be described with reference to  FIG.  1    and  FIG.  2   .  FIG.  1    is a schematic configuration diagram of the packaging apparatus  1 . It will be noted that, in  FIG.  1   , gripping arms  32  of a moving mechanism  30  described later are illustrated as transparent objects using long dashed double-short dashed lines.  FIG.  2    is a control block diagram of the packaging apparatus  1 . 
     The packaging apparatus  1  is an apparatus that closes, with a film F, openings in containers C to thereby package, with the film F, the containers C. 
     Specifically, the packaging apparatus  1  receives tray-like containers C that are filled with contents-to-be-packaged and are conveyed to the packaging apparatus  1 . It will be noted that the upper portions of the containers C received by the packaging apparatus  1  have openings. Namely, the packaging apparatus  1  receives the containers C that have been filled with the contents-to-be-packaged but have not yet been packaged by the film F. The packaging apparatus  1  seals (packages), with the film F, the openings in the upper portions of the containers C which the packaging apparatus  1  has received. The packaging apparatus  1  conveys the packaged containers C to a process downstream of the packaging apparatus  1 . 
     It will be noted that, although this is not intended to limit the type of the contents-to-be-packaged, the contents-to-be-packaged are, for example, a food. Although this is not intended to limit the type of the material of the containers C, the material of the containers C is, for example, a plastic such as polypropylene. Although this is not intended to limit the type of the material of the film F, the material of the film F is, for example, a plastic such as polypropylene. 
     The packaging apparatus  1  will now be more specifically described. 
     As shown in  FIG.  1    and  FIG.  2   , the packaging apparatus  1  mainly includes a first conveyor  10 , a second conveyor  20 , a moving mechanism  30 , a sealing device  40 , a third conveyor  50 , a film conveyance device  100 , a printer  140 , a mark detection sensor  160 , an encoder  170 , and a controller  200 . 
     The first conveyor  10  receives the containers C conveyed to the packaging apparatus  1  by conveying means such as a conveyor not shown in the drawings. The first conveyor  10  is, for example, a belt conveyor. The first conveyor  10  conveys the containers C to the second conveyor  20 . 
     The second conveyor  20  receives the containers C fed by the first conveyor  10 . The second conveyor  20  is, for example, a belt conveyor. A predetermined quantity of the containers C are gathered on the second conveyor  20 . The second conveyor  20  is controlled to operate and stop so that the predetermined quantity of the containers C become lined up a predetermined interval apart from each other along a conveyance direction A of the second conveyor  20  (see  FIG.  1   ) on the second conveyor  20 . 
     The moving mechanism  30  moves the predetermined quantity of the containers C that have been gathered on the second conveyor  20  to the sealing device  40 . The moving mechanism  30  also moves the containers C that have been packaged by the sealing device  40  (the containers C whose openings have been sealed by the film F) to the third conveyor  50 . 
     The sealing device  40  seals, with the film F conveyed thereto by the film conveyance device  100 , the openings of the containers C conveyed thereto by the moving mechanism  30 . The containers C that have been packaged by the sealing device  40  are moved by the moving mechanism  30  to the third conveyor  50 . 
     The third conveyor  50  receives the packaged containers C conveyed thereto by the moving mechanism  30  and then conveys the received packaged containers C and hands them over to the downstream process (e.g., conveying means such as a conveyor not shown in the drawings). 
     The film conveyance device  100  pays out and conveys the film F from a film roll R 1  in which the film F is wound and feeds the film F to the sealing device  40 . 
     The printer  140  prints predetermined information such as text and images on the film F before the film F conveyed by the film conveyance device  100  is fed to the sealing device  40 . 
     The mark detection sensor  160  detects marks that have been added at predetermined intervals to the film F conveyed by the film conveyance device  100 . The mark detection sensor  160  is used to control the timing of the printing by the printer  140 . 
     The encoder  170  detects the conveyance speed and the conveyance distance of the film F conveyed by the film conveyance device  100 . The encoder  170  is used to control the timing of the printing by the printer  140 . 
     The controller  200  controls the operations of the first conveyor  10 , the second conveyor  20 , the moving mechanism  30 , the sealing device  40 , the third conveyor  50 , the film conveyance device  100 , and the printer  140 . 
     (2) Details 
     The moving mechanism  30 , the sealing device  40 , the film conveyance device  100 , the printer  140 , the mark detection sensor  160 , the encoder  170 , and the controller  200  will now be described in detail with further reference to  FIG.  3    to  FIG.  4   .  FIG.  3 A  to  FIG.  3 D  are diagrams for describing the operation of the moving mechanism  30 . In  FIG.  3 A  to  FIG.  3 D , illustration of the film conveyance device  100 , the printer  140 , the mark detection sensor  160 , and the encoder  170  is omitted. Furthermore, in  FIG.  3 A  to  FIG.  3 D , the containers C that have been packaged by the film F are shown with hatching added to them.  FIG.  4    is a diagram schematically showing configurations in the vicinity of the film conveyance device  100 . 
     (2-1) Moving Mechanism 
     The moving mechanism  30  is an example of the container conveyance unit that conveys the containers C having the openings. The moving mechanism  30  moves the predetermined quantity of the containers C that have been gathered on the second conveyor  20  onto a later-described lifter  42  of the sealing device  40 . The moving mechanism  30  also moves the containers C whose openings have been sealed by the film F (the packaged containers C) and which are placed on the lifter  42  of the sealing device  40  to the third conveyor  50 . 
     The moving mechanism  30  is, for example, a mechanism such as follows, although this is not intended to be limiting. 
     As shown in  FIG.  1    and  FIG.  2   , the moving mechanism  30  has a pair of gripping arms  32  and a gripping arm drive unit  34  that operates the pair of gripping arms  32 . 
     The gripping arm drive unit  34  is, for example, a pneumatic cylinder, a hydraulic cylinder, or a motor. The gripping arm drive unit  34  may have a plurality of the pneumatic cylinders, hydraulic cylinders, or motors, and the plural pneumatic cylinders, hydraulic cylinders, or motors may work together to operate the gripping arms  32  as follows. 
     The pair of gripping arms  32  are bar-like members that extend in the conveyance direction A in which the containers C are conveyed by the second conveyor  20 . 
     The pair of gripping arms  32  are members that are movable between a first position and a second position in the conveyance direction A in which the containers C are conveyed by the second conveyor  20 . Hereinafter, in the description of the moving mechanism  30 , the conveyance direction A in which the containers C are conveyed by the second conveyor  20  will simply be called “the conveyance direction A.” The pair of gripping arms  32  in the first position in the conveyance direction A are disposed so that the second conveyor  20  and the sealing device  40  are interposed between the pair of gripping arms  32  in a direction B orthogonal to the conveyance direction A (see  FIG.  3 A  and  FIG.  3 B ). Hereinafter, in the description of the moving mechanism  30 , the direction B orthogonal to the conveyance direction A will simply be called “the direction B.” The pair of gripping arms  32  in the second position in the conveyance direction A are disposed so that the sealing device  40  and the third conveyor  50  are interposed between the pair of gripping arms  32  in the direction B (see  FIG.  3 C  and  FIG.  3 D ). 
     The pair of gripping arms  32  are also members that are movable between a third position and a fourth position in the direction B. The pair of gripping arms  32  disposed in the third position in the direction B are spaced further apart from each other than they are when they are disposed in the fourth position. The pair of gripping arms  32  disposed in the third position in the direction B are disposed away from the containers C that are on the lifter  42  of the sealing device  40  and the conveyor  20  or  50  in the direction B (see  FIG.  3 A  and  FIG.  3 D ). In other words, the pair of gripping arms  32  disposed in the third position in the direction B do not contact the containers C even when there are containers C on the lifter  42  of the sealing device  40  and the conveyor  20  or  50  (see  FIG.  3 A  and  FIG.  3 D ). The pair of gripping arms  32  disposed in the fourth position in the direction B contact the containers C that are on the lifter  42  of the sealing device  40  and the conveyor  20  or  50  and sandwich the containers C (see  FIG.  3 B  and  FIG.  3 C ). 
     The gripping arm drive unit  34  drives the pair of gripping arms  32  so that the pair of gripping arms  32  operates as follows. It will be noted that, as a premise for description, it will be assumed that the pair of gripping arms  32  are in the first position in the conveyance direction A and in the third position in the direction B as shown in  FIG.  3 A . 
     When the predetermined quantity of the containers C are gathered on the second conveyor  20  and the packaging of the containers C on the lifter  42  of the sealing device  40  by the film F is finished, the pair of gripping arms  32  are driven by the gripping arm drive unit  34  to move from the third position to the fourth position in the direction B. Then, the pair of gripping arms  32  grip the containers C that are on the second conveyor  20  and on the lifter  42  (see  FIG.  3 B ). The packaging of the containers C by the sealing device  40  will be described later. 
     Next, the pair of gripping arms  32  are driven by the gripping arm drive unit  34  to move to the second position in the conveyance direction A (see  FIG.  3 C ). As a result, the containers C that were on the second conveyor  20  move onto the lifter  42 . Furthermore, the containers C that were initially (before the pair of gripping arms  32  moved to the second position in the conveyance direction A) on the lifter  42  move onto the third conveyor  50 . It will be noted that the pair of gripping arms  32  move the containers C that were on the second conveyor  20  onto the lifter  42  and move the containers C that were initially on the lifter  42  onto the third conveyor  50  while maintaining the alignment of the containers C in the conveyance direction A. 
     In this state, the pair of gripping arms  32  are driven by the gripping arm drive unit  34  to move to the third position in the direction B (see  FIG.  3 D ) so that the gripping of the containers C by the pair of gripping arms  32  is canceled. 
     Thereafter, the pair of gripping arms  32  are driven by the gripping arm drive unit  34  to move to the first position in the conveyance direction A (see  FIG.  3 A ). 
     Then, when the predetermined quantity of the containers C are gathered on the second conveyor  20  and the packaging of the containers C on the lifter  42  by the film F is finished, the pair of gripping arms  32  again move to the fourth position in the direction B and grip the containers C that are on the second conveyor  20  and on the lifter  42 . 
     The moving mechanism  30  repeatedly performs this series of operations. 
     (2-2) Sealing Device 
     The sealing device  40  is an example of the packaging unit. 
     The sealing device  40  seals, with the film F conveyed thereto by the film conveyance device  100 , the openings of the predetermined quantity of the containers C conveyed thereto from the second conveyor  20  by the moving mechanism  30 . In particular, in this embodiment, the sealing device  40  collectively (simultaneously) seals, with the film F in one packaging operation, the openings of a plurality (in this embodiment, four) of the containers C lined up parallel to a conveyance direction D of the film F. The sealing device  40  individually packages product inside the plural containers C in one packaging operation. The containers C whose openings have been sealed with the film F by the sealing device  40  (the packaged containers C) are moved by the moving mechanism  30  to the third conveyor  50 . 
     As shown in  FIG.  1    and  FIG.  2   , the sealing device  40  mainly includes the lifter  42 , a plate  44 , and a lifter drive unit  46 . 
     As shown in  FIG.  1   , the film F conveyed by the film conveyance device  100  is conveyed between a placement surface  42   a  of the lifter  42  on which the containers C are placed and an opposing surface  44   a  of the plate  44  that opposes the placement surface  42   a  of the lifter  42 . 
     The lifter drive unit  46  is a mechanism that moves the lifter  42  in a direction toward the plate  44  and a direction away from the plate  44 . Although this is not intended to be limiting, the lifter drive unit  46  is, for example, a pneumatic cylinder, a hydraulic cylinder, or a motor. 
     The plate  44  is provided with tools  48  in positions that correspond, in the conveyance direction A of the second conveyor  20  (the conveyance direction D of the film F) and the direction B orthogonal to the conveyance direction A of the second conveyor  20 , to each of the containers C that have been moved by the moving mechanism  30  to the lifter  42 . 
     The tools  48  each have a heater and a cutter not shown in the drawings. The heater of each tool  48  is at least disposed in a position where the film F is sandwiched between the tool  48  and the edge portion of the opening of the corresponding container C (the part of the container C bordering the opening) when, as described later, the lifter  42  has been moved by the lifter drive unit  46  so that the container C moves toward the plate  44 . The cutter of each tool  48  is arranged so as to contact the film F and cut the film F at a predetermined position (at an appropriate position in the vicinity of the edge portion of the opening of the container C where the film F has been heat-sealed) when the container C has been moved by the lifter  42  toward the plate  44 . 
     Stating differently the relationship between the positions of the containers C on the lifter  42  and the positions of the tools  48 , the moving mechanism  30  moves the containers C that are on the second conveyor  20  to positions that correspond, in the conveyance direction A of the second conveyor  20  and the direction B orthogonal to the conveyance direction A, to the tools  48  provided on the plate  44 . To further state this differently, the second conveyor  20  aligns and gathers the predetermined quantity of the containers C on the second conveyor  20  so that the containers C are disposed in positions that correspond to the tools  48  provided on the plate  44  when the moving mechanism  30  has moved the containers C that are on the second conveyor  20  onto the lifter  42 . 
     The lifter  42  is disposed in a predetermined position (a distal position) away from the plate  44  when the lifter  42  receives the containers C conveyed thereto by the moving mechanism  30  from the second conveyor  20 . When the moving mechanism  30  moves the predetermined quantity of the containers C from the second conveyor  20  to the placement surface  42   a  of the lifter  42 , the lifter drive unit  46  moves the lifter  42  of the sealing device  40  to a predetermined position (a proximal position) so that the placement surface  42   a  of the lifter  42  moves toward the opposing surface  44   a  of the plate  44 . More specifically, the lifter drive unit  46  moves the lifter  42  of the sealing device  40  from the distal position to the proximal position so that the edge portions of the openings of the containers C on the lifter  42  contact the heaters of the tools  48  of the plate  44  via the film F. In this way, the edge portions of the openings of the containers C on the lifter  42  contact the heaters of the tools  48  via the film F, whereby the film F is heat-sealed to the edge portions of the openings of the containers C, and the openings of the containers C are sealed by the film F. Furthermore, when the lifter drive unit  46  moves the lifter  42  from the distal position to the proximal position so that the placement surface  42   a  of the lifter  42  moves toward the opposing surface  44   a  of the plate  44 , the cutters of the tools  48  contact the film F and cut the film F at the predetermined positions. It will be noted that the film F that was not utilized (the film F that was not used to seal the openings of the containers C) is sent to a recovery roll retention unit  130  described later. 
     In the sealing device  40 , after the lifter  42  has been moved to approach to the plate  44 , the lifter drive unit  46  moves the lifter  42  from the proximal position to the distal position so that the lifter  42  moves away from the plate  44 . In other words, in the sealing device  40 , after the openings of the containers C have been sealed with the film F and the film F (film pieces) for sealing the openings of the containers C has been cut away from the film F conveyed by the film conveyance device  100 , the lifter  42  is moved from the proximal position to the distal position so that the lifter  42  moves away from the plate  44 . The containers C that are placed on the placement surface  42   a  of the lifter  42  positioned in the distal position and whose openings have been sealed with the film F by the sealing device  40  (the packaged containers C) are moved by the moving mechanism  30  to the third conveyor  50 . 
     (2-3) Film Conveyance Device 
     The film conveyance device  100  is an example of the film conveyance unit. The film conveyance device  100  pays out and conveys the film F from the film roll R 1  in which the film F used to seal the openings of the containers C is wound and feeds the film F to the sealing device  40 . 
     As shown in  FIG.  1    and  FIG.  4   , the film conveyance device  100  mainly has a film roll retention unit  110 , a recovery roll retention unit  130 , and an accumulation mechanism  120 . The film conveyance device  100  uses plural rollers to guide the film F paid out from the film roll R 1  retained by the film roll retention unit  110  and feed the film F between the placement surface  42   a  of the lifter  42  of the sealing device  40  and the opposing surface  44   a  of the plate  44 . As mentioned above, the film F from which the film F (film pieces) used to seal the openings of the containers C in the sealing device  40  has been cut out (called “used film F”) is conveyed to the recovery roll retention unit  130 . The used film F conveyed to the recovery roll retention unit  130  is recovered on a recovery roll R 2  retained by the recovery roll retention unit  130 . 
     (2-3-1) Film Roll Retention Unit 
     As shown in  FIG.  2    and  FIG.  4   , the film roll retention unit  110  has a first shaft  112  and a first shaft drive unit  114 . The film roll R 1  in which the film F is wound is mounted to the first shaft  112 . The first shaft drive unit  114  is a mechanism that rotates the first shaft  112 . The first shaft drive unit  114  is, for example, a motor. The first shaft drive unit  114  rotates the first shaft  112  to thereby rotate the film roll R 1  mounted on the first shaft  112 , thus paying out the film F from the film roll R 1  and conveying to the sealing device  40  the film F that is paid out. 
     (2-3-2) Recovery Roll Retention Unit 
     The recovery roll retention unit  130  has a second shaft  132  and a second shaft drive unit  134 . The recovery roll R 2 , to whose roll core the leading end of the film F paid out from the film roll F 1  is connected, is mounted to the second shaft  132 . The second shaft drive unit  134  is a mechanism that rotates the second shaft  132 . The second shaft drive unit  134  is, for example, a motor. The second shaft drive unit  134  rotates the second shaft  132  to thereby rotate the recovery roll R 2  mounted on the second shaft  132 , thus taking up the used film F on the recovery roll R 2 . 
     It is preferred that the speed for paying out the film F from the film roll F 1  by rotating the first shaft drive unit  114  be slower than the speed for taking up the film F on the recovery roll R 2  by rotating the second shaft drive unit  134 . Specifically, it is preferred that the conveyance speed of the film F between the film roll retention unit  110  and the accumulation mechanism  120  be slower than the conveyance speed of the film F between the accumulation mechanism  120  and the recovery roll retention unit  130 . By configuring the speeds in this way, the conveyance speed of the film F from the printer  140  disposed between the film roll retention unit  110  and the accumulation mechanism  120  in the conveyance path of the film F to the accumulation mechanism  120  becomes slower than the conveyance speed of the film F downstream of the accumulation mechanism  120 . For example, the average conveyance speed of the film F from the printer  140  to the accumulation mechanism  120  is 0.3 to 0.4 times the average conveyance speed of the film F downstream of the accumulation mechanism  120 . By making the conveyance speed of the film F in the printer  140  relatively slower in this way, the amount of time that the printer  140  can use for printing becomes relatively longer, and a reduction in the printing quality of the printer can be inhibited. 
     (2-3-3) Accumulation Mechanism 
     The accumulation mechanism  120  is disposed between the film roll retention unit  110  and the recovery roll retention unit  130  in the conveyance path of the film F. More specifically, the accumulation mechanism  120  is disposed between the printer  140 , which serves as an example of the printing unit that prints predetermined information such as text and images on the film F, and the sealing device  40 , which serves as an example of the packaging unit, in the conveyance path of the film F. The accumulation mechanism  120  is a mechanism that temporarily accumulates the film F on which the information has been printed by the printer  140 . 
     As shown in  FIG.  2    and  FIG.  4   , the accumulation mechanism  120  includes fixed rollers  121 , movable rollers  122 , a movable roller drive unit  124 , and a position sensor  126 . 
     The fixed rollers  121  and the movable rollers  122  are rollers around which the film F is wound and which guide the film F. As shown in  FIG.  4   , the fixed rollers  121  and the movable rollers  122  are alternately disposed in the conveyance path of the film F. In the example shown in  FIG.  4   , the accumulation mechanism  120  has three fixed rollers  121  and two movable rollers  122 . However,  FIG.  4    should not be construed as limiting the numbers of the fixed rollers  121  and the movable rollers  122 . The numbers of the fixed rollers  121  and the movable rollers  122  may be appropriately selected. 
     The fixed rollers  121  are rollers whose positions do not change during operation of the film conveyance device  100 . In contrast, the movable rollers  122  are rollers whose positions can be changed to change the length of the conveyance path of the film F. Although this is not intended to limit the moving direction of the movable rollers  122 , in the example of  FIG.  4   , the movable rollers  122  change the length of the conveyance path of the film F by moving generally in the up and down direction between the positions illustrated with solid lines and the positions illustrated with dashed lines. 
     By virtue of having the movable rollers  122 , the accumulation mechanism  120  can temporarily accumulate the film F, particularly the film F on which the information has been printed by the printer  140 . It is preferred that at least the film F that is utilized for one packaging operation in the sealing device  40  can be accumulable in the accumulation mechanism  120 . Specifically, in the example shown in  FIG.  1   , it is preferred that at least the film F (the film F on which the information has been printed by the printer  40 ) sufficient for four containers, which are packaged at one time in the sealing device  40 , be accumulable in the accumulation mechanism  120 . 
     The position of the movable rollers  122  is detected by the position sensor  126  that detects the position of the movable rollers  122 . The position sensor  126  is, for example, an encoder that detects the amount of rotation of arms (not shown in the drawings) that support the movable rollers  122 . The position sensor  126  may also be a device that uses a photoelectric sensor, for example, to detect whether the movable rollers  122  are in a predetermined position. 
     The movable roller drive unit  124  is a mechanism that drives the movable rollers  122 . Although this is not intended to be limiting, the movable roller drive unit  124  is, for example, an air cylinder or a motor. The movable roller drive unit  124  exerts force on the movable rollers  122  to increase the amount of the film F that is accumulated in the accumulation mechanism  120 . Although this is not intended to limit the direction in which the movable rollers  122  exerts force on the film F, for example, in the example illustrated in  FIG.  4   , the movable roller drive unit  124  biases the movable rollers  122  downward so that the movable rollers  122  move downward. 
     In this embodiment, the film conveyance device  100  uses the first shaft drive unit  114 , the second shaft drive unit  134 , and the movable roller drive unit  124  to convey the film F. However, the means for conveying the film F are not limited to the first shaft drive unit  114 , the second shaft drive unit  134 , and the movable roller drive unit  124 . The film conveyance device  100  may further have, as means for conveying the film F, a mechanism for film conveyance such as pinch rollers that pinch the film F between a pair of rollers and convey the film F by pulling it. 
     The timing when the accumulation mechanism  120  accumulates the printed film F and effects obtained as a result of the accumulation mechanism  120  accumulating the printed film F will be described in description of the control of the operations of each part of the packaging apparatus  1  by the controller  200 . 
     (2-4) Printer 
     The printer  140  is an example of the printing unit. 
     The printer  140  is disposed upstream of the sealing device  40  in the conveyance path along which the film F is conveyed by the film conveyance device  100 . The printer  140  prints the predetermined information such as text and images in predetermined positions on the film F before the film F conveyed by the film conveyance device  100  is fed to the sealing device  40 . 
     In a case where, for example, the product with which the containers C are filled is a food, the information printed on the film F by the printer  140  is the name of the food, the ingredients of the food, allergy information about the food, the date of manufacture of the food, the expiration date of the food, and a barcode, for example. However, the content of the information printed by the printer  140  and exemplified here is merely an example and is not limited to these items of information. 
     By printing the information in the predetermined positions on the film F by the printer  140 , the packaged containers C, to which the film pieces cut out from the film F are attached to the containers C in the sealing device  40 , has the information printed in predetermined positions. 
     The printer  140  is a thermal transfer printer. As shown in  FIG.  4   , the printer  140  includes an ink ribbon  142 , a thermal head  144 , and a print roller  146 . The printer  140  performs printing by moving the thermal head  144  closer to the print roller  146  while starting to convey the ink ribbon  142 , pinching the ink ribbon  142  and the film F between the thermal head  144  and the print roller  146 , and transferring hot-melt pigment ink of the ink ribbon  142  to the film F by means of heat of the thermal head  144 . 
     (2-5) Mark Detection Sensor 
     The mark detection sensor  160  detects marks (alignment marks) added at predetermined intervals along the conveyance direction of the film F to the film F conveyed by the film conveyance device  100 . 
     The mark detection sensor  160  detects, between the film roll R 1  and the place where printing is performed by the printer  140  in the conveyance path along which the film F is conveyed by the film conveyance device  100 , the marks added to the film F. The mark detection sensor  160  is used to control the timing of printing by the printer  140  so that the predetermined text and images are printed in the predetermined positions on the film F conveyed by the film conveyance device  100 . 
     (2-6) Encoder 
     The encoder  170  is a sensor that detects the conveyance speed and the conveyance distance of the film F conveyed by the film conveyance device  100 . 
     The encoder  170  is connected to the print roller  146  of the printer  140  and detects, from the rotational speed of the print roller  146 , the conveyance speed and the conveyance distance of the film F conveyed by the film conveyance device  100 . The encoder  170 , together with the mark detection sensor  160 , is used to control the timing of printing by the printer  140  so that the predetermined text and images are printed in the predetermined positions on the film F conveyed by the film conveyance device  100 . 
     (2-7) Controller 
     The controller  200  is an example of the control unit that controls the operations of each part of the packaging apparatus  1 . 
     The controller  200  of this embodiment mainly includes a CPU, a memory comprising a ROM, a RAM, and an auxiliary storage device (e.g., flash memory), and various types of electronic circuits. The controller  200  controls the operations of each part of the packaging apparatus  1  as a result of the CPU reading and executing programs stored in the memory. 
     It will be noted that the configuration of the controller  200  described here is merely an example of the configuration of the controller  200 . The controller of the packaging apparatus  1  may realize the same functions as those of the controller  200  of this embodiment by means of hardware such as a logic circuit or by means of a combination of hardware and software. Furthermore, the controller  200  may be realized by one device or by plural devices. 
     As shown in  FIG.  2   , the controller  200  is electrically connected to the first conveyor  10 , the second conveyor  20 , the third conveyor  50 , the gripping arm drive unit  34 , and the lifter drive unit  46 . The controller  200  is also electrically connected to the first shaft drive unit  114 , the second shaft drive unit  134 , and the movable roller drive unit  124  of the film conveyance device  100 . The controller  200  is also electrically connected to the printer  140 . It will be noted that “electrically connected” here means that the controller  200  is connected so as to be able to control the devices to which it is connected. In other words, the controller  200  controls the operations of the conveyors  10 ,  20 , and  50 , the film conveyance device  100  serving as an example of the film conveyance unit, the moving mechanism  30  serving as an example of the container conveyance unit, the sealing device  40  serving as an example of the packaging unit, and the printer  140  serving as an example of the printing unit. 
     The controller  200  is also connected to the position sensor  126 , the mark detection sensor  160 , and the encoder  170  of the film conveyance device  100  so as to be able to receive information (detection results) from them. 
     The controller  200  is also configured to be able to receive instructions and information input via an input unit  210  by the operator of the packaging apparatus  1 . The input unit  210  may be switches and/or a touch panel provided in the packaging apparatus  1  or may be a unit that receives input sent from a mobile device or the like operated by the operator of the packaging apparatus  1 . 
     The control of the operations of the packaging apparatus  1  by the controller  200  will be described below. 
     (A) Operations of Each Part of Packaging Apparatus with Respect to Containers 
     The control of the operations of each part of the packaging apparatus  1  with respect to the containers C by the controller  200  will now be described with reference to  FIG.  5   .  FIG.  5    is a flowchart for mainly describing operations by which the containers C are packaged by the packaging apparatus  1 . 
     The controller  200  controls the operation of the first conveyor  10  to convey the containers C received by the first conveyor  10  onto the second conveyor  20 . The controller  200  also controls the second conveyor  20  to start and stop so that the containers C become aligned a predetermined interval apart from each other in the conveyance direction A of the second conveyor  20  on the second conveyor  20 . 
     Then, when the predetermined quantity of the containers C are gathered on the second conveyor  20 , the controller  200  controls the operation of the gripping arm drive unit  34  so that the predetermined quantity of the containers C on the second conveyor  20  are gripped by the gripping arms  32  as shown in  FIG.  3 B . Then, the controller  200  moves the gripping arms  32  along the conveyance direction A of the second conveyor  20  to convey the predetermined quantity of the containers C that are on the second conveyor  20  onto the placement surface  42   a  of the lifter  42  of the sealing device  40  as shown in  FIG.  3 C  (Step S 1 ). It will be noted that, as mentioned above, at this time, as shown in  FIG.  3 C , the moving mechanism  30  moves the predetermined quantity of the containers C that are on the second conveyor  20  onto the placement surface  42   a  of the lifter  42  and also moves the packaged containers C that were on the placement surface  42   a  of the lifter  42  onto the third conveyor  50 . 
     When the movement of the containers C from the second conveyor  20  onto the placement surface  42   a  of the lifter  42  is finished, the controller  200  controls the operation of the gripping arm drive unit  34  to cancel the gripping of the containers C by the gripping arms  32  (see  FIG.  3 D ) and thereafter moves the gripping arms  32  to the position shown in  FIG.  3 A . 
     When the moving mechanism  30  moves the predetermined quantity of the containers C that are on the second conveyor  20  onto the placement surface  42   a  of the lifter  42 , the controller  200  controls the operations of the first conveyor  10  and the second conveyor  20  to start gathering the predetermined quantity of the containers C on the second conveyor  20  (Step S 2 ). The controller  200  continues to control the operations of the first conveyor  10  and the second conveyor  20  until the predetermined quantity of the containers C are gathered on the second conveyor  20 . 
     In parallel with the control of Step S 2 , the controller  200  controls the operation of the lifter drive unit  46  to move the placement surface  42   a  of the lifter  42  toward the tools  48  provided in the opposing surface  44   a  of the plate  44  in a state in which the film F is disposed in a predetermined position (an appropriate position relative to the position of the containers C on the placement surface  42   a  of the lifter  42 ). By doing so, the controller  200  heat-seals, with the heaters of the tools  48 , the film F to the openings of the containers C (step S 3 ). 
     When Step S 3  is executed, the cutters of the tools  48  provided in the opposing surface  44   a  of the plate  44  cut the film F at predetermined positions in conjunction with the sealing of the openings of the containers C by the film F. As a result, the film pieces of the film F sealing the openings of the containers C and the film that becomes conveyed to the recovery roll R 2  are cut apart from each other. 
     When the sealing of the openings of the containers C on the placement surface  42   a  of the lifter  42  by the film F in Step S 3  is finished, the controller  200  controls the operation of the gripping arm drive unit  34  so that the predetermined quantity of the containers C on the lifter  42  are gripped by the gripping arms  32  as shown in  FIG.  3 B . Then, the controller  200  moves the gripping arms  32  along the conveyance direction A of the second conveyor  20  to convey the predetermined quantity of the containers C that are on the lifter  42  onto the third conveyor  50  as shown in  FIG.  3 C  (step S 4 ). It will be noted that, as described in the description of Step S 1 , when Step S 4  is executed, the moving mechanism  30  simultaneously moves the predetermined quantity of the containers C that are on the second conveyor  20  onto the placement surface  42   a  of the lifter  42 . When the movement of the containers C onto the third conveyor  50  is finished, the controller  200  controls the operation of the gripping arm drive unit  34  to cancel the gripping of the containers C by the gripping arms  32  (see  FIG.  3 D ) and thereafter moves the gripping arms  32  to the position shown in  FIG.  3 A . 
     The controller  200  conveys the containers C that are on the third conveyor  50  and hands over the containers C to the process downstream of the packaging apparatus  1 . 
     (B) Operation of Film Conveyance Device 
     The control of the operation of the film conveyance device  100  by the controller  200  will now be described with reference to  FIG.  6   .  FIG.  6    is a flowchart for mainly describing the operation of the film conveyance device  100 . 
     First, film conveyance and its problems in a case where, as in a conventional packaging apparatus, the film conveyance device  100  does not have the accumulation mechanism  120  will be described. 
     In this packaging apparatus  1 , when sealing, with the film F, the openings of the containers C in the sealing device  40 , it is necessary to stop the conveyance of the film F in the sealing device  40 . For that reason, if the film conveyance device  100  did not have the accumulation mechanism  120 , when the conveyance of the film F is stopped in the sealing device  40 , the conveyance of the film F between the film roll retention unit  110  and the sealing device  40  would also stop. Additionally, because the printer  140  performs printing on the film F conveyed by the film conveyance device  100 , if the conveyance of the film F between the film roll retention unit  110  and the sealing device  40  stops, the operation of the printer  140  would also stop. As a result, in a packaging apparatus where the film conveyance device  100  does not have the accumulation mechanism  120 , the amount of time in which the printer  140  is able to print on the film F becomes, at a maximum, an amount of time obtained by subtracting, from the operating time of the packaging apparatus  1 , the time in which the conveyance of the film F is stopped when the openings of the containers C are sealed by the film F in the sealing device  40 . For that reason, in a packaging apparatus where the film conveyance device  100  does not have the accumulation mechanism  120 , the amount of time in which the printer  140  is able to print on the film F is relatively short, and particularly if the number of the containers C that the packaging apparatus  1  packages per unit of time were to be increased, this would run the risk of reducing the printing quality of the printer  140 . 
     In contrast, in this embodiment, because the film conveyance device  100  has the accumulation mechanism  120 , as described in detail below, even when the conveyance of the film F in the sealing device  40  is stopped, the conveyance of the film F can be continued between the film roll retention unit  110  and the accumulation mechanism  120 . Consequently, in the packaging apparatus  1  of this embodiment, the time in which the conveyance of the film F in the sealing device  40  is stopped can also be used for time for printing on the film F. For that reason, in the packaging apparatus of this embodiment, even if the number of the containers C packaged per unit of time is increased, there is unlikely to be a reduction in printing quality on the film F. 
     Below, the control of the operation of the film conveyance device  100  by the controller  200  will be described. 
     As a premise for description, it will be assumed that at the point in time when the process of Step S 11  described below is started, a predetermined length of the film F on which printing has been performed by the printer  140  has already been accumulated in the accumulation mechanism  120 . In particular, here, it will be assumed that at the point in time when the process of Step S 11  is started, the printed film F that is used in one sealing operation by the sealing device  40  (in this embodiment, sufficient for four of the containers C) has been accumulated in the accumulation mechanism  120 . Furthermore, here, as a premise for description, it will be assumed that at the point in time when the process of Step S 11  described below is started, the film conveyance device  100  has stopped conveyance of the film F on the entire conveyance path of the film F. 
     In this state, when the sealing device  40  finishes sealing the openings of the containers C using the film F that has already been fed to the sealing device  40 , the controller  200  starts up the second shaft drive unit  134  to start conveying the film F on the downstream side of the accumulation mechanism  120  while keeping the operation of the first shaft drive unit  114  stopped (Step S 11 ). As the film F is not fed from the film roll R 1  in this state, the printed film F accumulated in the accumulation mechanism  120  is conveyed to the sealing device  40 . At this time, the movable rollers  122  of the accumulation mechanism  120  move, due to tension in the film F, in the direction in which the amount of the film F accumulated in the accumulation mechanism  120  becomes less. In the example of  FIG.  4   , the movable rollers  122  move upward toward the fixed rollers  121  due to tension in the film F. 
     At this time, the controller  200  grasps the position of the movable rollers  122  using the detection result of the position sensor  126 . The controller  200  determines, based on the detection result of the position sensor  126 , whether the movable rollers  122  have moved to a predetermined position (referred to “position a” hereinafter) as a result of the amount of film F accumulated in the accumulation mechanism  120  has decreased (step S 12 ). 
     Then, when the controller  200  determines that the movable rollers  22  have moved to “position a”, the controller  200  starts up the first shaft drive unit  114  to start paying out the film F from the film roll R 1  and to start conveying the film F between the film roll R 1  and the accumulation mechanism  120  (Step S 13 ). Moreover, in Step S 13 , the controller  200  sends operation commands to the printer  140  at appropriate timings so that the information is printed in the predetermined positions on the film F based on the detection results of the mark detection sensor  160  detecting the marks added to the film F and the amount of the film F—detected by the encoder  170 —conveyed since the point in time when the marks added to the film F pass the detection position of the mark detection sensor  160 . The printer  140  operates the ink ribbon  142  and the thermal head  144  to print the information on the film F in response to the operation commands. 
     It will be noted that the controller  200  grasps the amount of the film F fed to the sealing device  40  utilizing, for example, sensors (not shown in the drawings) disposed downstream of the accumulation mechanism  120  in the conveyance direction D in which the film F is conveyed by the film conveyance device  100 . In other words, the controller  200  determines whether the printed film F that will be used in the sealing device  40  in the next packaging operation has moved to a predetermined position (Step S 14 ). 
     When the controller  200  determines that the printed film F that will be used in the sealing device  40  in the next packaging operation has moved to the predetermined position (Yes in Step S 14 ), the controller  200  stops the conveyance of the film F in the sealing device  40  so that the sealing device  40  can seal, with the film F, the openings of the containers C. Specifically, when the controller  200  determines that the printed film F that will be used in the sealing device  40  in the next packaging operation has moved to the predetermined position, the controller  200  stops the conveyance of the film F downstream of the accumulation mechanism  120  in the conveyance direction D of the film F. More specifically, when the controller  200  determines that the printed film F that will be used in the sealing device  40  in the next packaging operation has moved to the predetermined position, the controller  200  stops operating the second shaft drive unit  134  to stop the conveyance of the film F on the downstream side of the accumulation mechanism  120  in the conveyance direction D of the film F (Step S 15 ). 
     Moreover, at this point in time, the controller  200  drives the movable roller drive unit  124  to move the movable rollers  122  so as to increase the amount of the film F accumulated in the accumulation mechanism  120  (Step S 16 ). In the example of  FIG.  4   , the controller  200  drives the movable roller drive unit  124  to move the movable rollers  122  downward. By moving the movable rollers  122  downward in this way, the conveyance of the film F on the upstream side of the accumulation mechanism  120  can be continued while the conveyance of the film F on the downstream side of the accumulation mechanism  120  is stopped. 
     It will be noted that the controller  200  also continues the process of sending the operation commands at appropriate timings to the printer  140  until the determination result becomes “Yes” in step S 17  described later. 
     The controller  200  uses the detection result of the position sensor  126  to grasp the position of the movable rollers  122  that are moving so as to increase the amount of the film F accumulated in the accumulation mechanism  120 . The controller  200  determines, based on the detection result of the position sensor  126 , whether the amount of the film F accumulated in the accumulation mechanism  120  has increased and the movable rollers  122  have moved to a predetermined position (referred to “position b” hereinafter) (Step S 17 ). It will be noted that the “position b” here is set so that the film F that is utilized for one packaging operation in the sealing device  40  has been accumulated in the accumulation mechanism  120  when the movable rollers  122  are in this position. 
     When the controller  200  determines in step S 17  that the movable rollers  122  are in the “position b”, the controller  200  stops operating the first shaft drive unit  114  and stops operating the movable roller drive unit  124  (Step S 18 ). 
     It is preferred that the “position b” used in the determination of Step S 17 —in other words, the position of the movable rollers  122  when the film F has accumulated the most in the accumulation mechanism  120 —be configured so that the controller  200  which serves as the changing unit can change the “position b” in response to input to the input unit  210 . In other words, it is preferred that the controller  200  change the maximum film length accumulable by the accumulation mechanism  120  in response to input to the input unit  210 . By configuring the controller  200  in this way, even when the size of the containers C packaged by the packaging apparatus  1 , the quantity of the containers C packaged at one time by the sealing device  40 , and/or the positions in which the printer  140  prints on the film F change, the film F can be stopped at an appropriate position that will not affect printing by the printer  140  when temporarily stopping the conveyance of the film by the film conveyance device  100 . In other words, by virtue of having the changing unit, it can be ensured that the film F is not stopped in the middle of printing by the printer  140 . 
     It will be noted that although a case where the changing unit is the controller  200  has been described as an example here, the changing unit is not limited to this. 
     The changing unit may also, for example, be a frame  128  to which the movable rollers  122  are movably attached. The frame  128  here is a member whose position relative to a mainframe (not shown in the drawings) of the packaging apparatus  1  can be changed. Preferably, the frame  128  is a member whose position relative to the mainframe can be manually changed. However, the frame  128  may be a member whose position relative to the mainframe is changed by a drive unit such as a motor rather than manually. It will be noted that, here, the fixed rollers  121  of the accumulation mechanism  120  are fixed to the mainframe. The frame  128  is configured so that the distance between the movable rollers  122  and the fixed rollers  121  at the time when the movable rollers  122  are disposed in the position farthest away from the fixed rollers  121  in the frame  128  can be changed in accordance with a change in the position of the frame  128  relative to the mainframe. 
     (3) Characteristics 
     (3-1) 
     The packaging apparatus  1  of the above embodiment includes the film conveyance device  100  serving as an example of a film conveyance unit, the moving mechanism  30  serving as an example of a container conveyance unit, the sealing device  40  serving as an example of a packaging unit, the printer  140  serving as an example of a printing unit, and the controller  200  serving as an example of a control unit. The film conveyance device  100  conveys the film F. The moving mechanism  30  conveys the container C having an opening. The sealing device  40  seals, with the film F conveyed thereto by the film conveyance device  100 , the opening of the container C conveyed thereto by the moving mechanism  30 . The printer  140  is disposed upstream of the sealing device  40  in the conveyance path along which the film F is conveyed by the film conveyance device  100 . The printer  140  prints information in a predetermined position on the film F while the film F being conveyed by the film conveyance device  100 . The controller  200  controls the operations of the film conveyance device  100 , the moving mechanism  30 , the sealing device  40 , and the printer  140 . The film conveyance device  100  has the accumulation mechanism  120 . The accumulation mechanism  120  is disposed between the printer  140  and the sealing device  40  in the conveyance path of the film F. The accumulation mechanism  120  temporarily accumulates the film F printed with the information. The controller  200  controls the film conveyance device  100  so that the accumulation mechanism  120  accumulates at least the film F that is utilized for one packaging operation in the sealing device  40 . 
     In the packaging apparatus  1  of the above embodiment, the time in which conveyance of the film F is stopped or slowed down on the downstream side of the accumulation mechanism  120  in the conveyance path of the film F can also be utilized for time for printing on the film F. For that reason, in the packaging apparatus  1 , time for printing can be ensured and a high printing quality on the film F can be maintained. 
     (3-2) 
     In the packaging apparatus  1  of the above embodiment, the conveyance speed of the film F from the printer  140  to the accumulation mechanism  120  is slower than the conveyance speed of the film F downstream of the accumulation mechanism  120 . 
     In this packaging apparatus  1 , by virtue of having the accumulation mechanism  120 , it is not necessary to synchronize the printing speed of the printer  140  with the conveyance speed of the film F on the downstream side of the accumulation mechanism  120 . For that reason, in this packaging apparatus  1 , a high printing quality on the film F can be maintained even when the film F is fed at a high speed to the printer  140 . 
     (3-3) 
     In the packaging apparatus  1  of the above embodiment, the film conveyance device  100  conveys the film F in the printer  140  while stopping conveyance of the film F in the sealing device  40  at least for a predetermined period of time. 
     Because the packaging apparatus  1  of the above embodiment has the accumulation mechanism  120 , the time in which conveyance of the film F is stopped for packaging can be utilized for time for printing on the film F by the printer  140 . For that reason, in the packaging apparatus  1 , a high printing quality on the film F can be maintained. 
     (3-4) 
     In the packaging apparatus  1  of the above embodiment, the sealing device  40  collectively seals, with the film F, the openings of a plurality of the containers C lined up parallel to the conveyance direction of the film F in the sealing device  40  in the one packaging operation. 
     In this packaging apparatus  1 , it becomes necessary to feed a length of the film F sufficient for the plural containers for every packaging operation by the sealing device  40 . For that reason, if the packaging apparatus  1  did not have the accumulation mechanism, it would be necessary to complete the plural containers&#39; worth of printing in, at most, the amount of time from the end of a packaging operation to the start of the next packaging operation. 
     In contrast, because the packaging apparatus  1  has the accumulation mechanism  120 , the film F can be conveyed and printing can be performed on the film F even during execution of the packaging operation, and a high printing quality on the film F can be maintained. 
     (3-5) 
     The packaging apparatus  1  of the above embodiment includes the changing unit that changes a maximum film length accumulable by the accumulation mechanism  120 . 
     The changing unit is, for example, the controller  200  that changes the “position b” used in step S 17  of the flowchart of  FIG.  6    in response to input to the input unit  210 . 
     Furthermore, the changing unit may also, for example, be the frame  128  to which the movable rollers  122  are movably attached. The frame  128  here is a member whose position relative to the mainframe (not shown in the drawings) of the packaging apparatus  1  can be changed. Preferably, the frame  128  is a member whose position relative to the mainframe can be manually changed. However, the frame  128  may also be a member whose position relative to the mainframe is changed by a drive unit such as a motor rather than manually. It will be noted that, here, the fixed rollers  121  of the accumulation mechanism  120  are fixed to the mainframe. The frame  128  is configured so that the distance between the movable rollers  122  and the fixed rollers  121  at the time when the movable rollers  122  are disposed in the position farthest away from the fixed rollers  121  in the frame  128  can be changed in accordance with a change in the position of the frame  128  relative to the mainframe. 
     It will be noted that the changing unit described here is merely exemplary and that the changing unit may have other structures/configurations as long as it is able to change the maximum film length accumulable by the accumulation mechanism  120 . 
     In the packaging apparatus  1  of the above embodiment, even when the size of the containers C, the quantity of the containers C packaged at one time by the sealing device  40 , and/or the positions in which the printer  140  prints on the film F change, the film F can be stopped at an appropriate position that will not affect printing by the printer  140  when temporarily stopping conveyance of the film F by the film conveyance device  100 . In other words, by virtue of having the changing unit, it can be ensured that the film F is not stopped in the middle of printing by the printer  140 . 
     (3-6) 
     The packaging apparatus  1  of the above embodiment stops the printing operation in the printer  140  in a case where the film F that is utilized for the one packaging operation in the sealing device  40  is accumulated in the accumulation mechanism  120 . 
     In the packaging apparatus  1 , the film conveyance device  100  stands by in a state in which the film F that is used for one packaging operation has been accumulated in the accumulation mechanism  120 , so the film F printed with the information can be provided without delay to the sealing device  40  in correspondence with the timing of the operation of the sealing device  40 . 
     At the same time, the accumulation mechanism  120  does not overly accumulate the film F, so the size of the accumulation mechanism  120  can be inhibited from being excessively large. 
     (4) Example Modifications 
     Example modifications of the embodiment will be described below. It will be noted that the example modifications described below may be appropriately combined to the extent that they are not mutually contradictory. 
     (4-1) Example Modification A 
     In the above embodiment, a case where the printer  140  is a thermal transfer printer using the ink ribbon  142  was described as an example, but the type of the printer  140  is not limited to a thermal transfer printer. For example, a substance that produces color by heat may be partially applied to the film F beforehand, so that printing can be performed on the film F without using the ink ribbon  142 . Furthermore, the configuration of the above embodiment is also useful in a case where, for example, the printer  140  is an inkjet printer. 
     (4-2) Example Modification B 
     In the above embodiment, a plurality of the containers C are gathered on the second conveyor  20 , the moving mechanism  30  conveys the plural containers C to the sealing device  40 , and the sealing device  40  collectively seals, with the film F, the openings of the plural containers C. 
     However, the packaging apparatus  1  is not limited to this. The moving mechanism  30  may convey the containers C one at a time to the sealing device  40 , and the sealing device  40  may seal, with the film F, the opening of a single container C. However, in terms of efficiently packaging the containers C, it is preferred that the moving mechanism  30  convey a plurality of the containers C to the sealing device  40  and that the sealing device  40  seal, with the film F, the openings of the plural containers C. 
     (4-3) Example Modification C 
     In the above embodiment, the moving mechanism  30  moves the predetermined quantity of the containers C that have been gathered on the second conveyor  20  to the sealing device  40  and simultaneously moves the packaged containers C that are on the sealing device  40  to the third conveyor  50 . However, the packaging apparatus  1  is not limited to this. The packaging apparatus  1  may have a first moving mechanism that moves the predetermined quantity of the containers C that have been gathered on the second conveyor  20  to the sealing device  40  and a second moving mechanism, separate from the first moving mechanism, that moves the packaged containers C that are on the sealing device  40  to the third conveyor  50 . 
     INDUSTRIAL APPLICABILITY 
     The present invention can be widely used in packaging apparatus that seal, with a film, openings of containers contained thereto, and is useful. 
     REFERENCE SIGNS LIST 
     
         
           1  Packaging Apparatus 
           30  Moving Mechanism (Container Conveyance Unit) 
           40  Sealing Device (Packaging Unit) 
           100  Film Conveyance Device (Film Conveyance Unit) 
           120  Accumulation Mechanism 
           128  Frame (Changing Unit) 
           140  Printer (Printing Unit) 
           200  Controller (Control Unit, Changing Unit) 
         C Containers 
         F Film 
       
    
     CITATION LIST 
     Patent Literature 
     Patent Document 1: JP-A No. H10-203505