Abstract:
A packaging system is disclosed that packages a product by supplying the product onto a lifter by means of a supply device, pushing the product on the lifter up to a packaging station, and covering the top surface of the product with a film. The packaging system includes a conveying unit that contacts the rear end in the conveying direction of the product on the supply device and configured to convey the product onto the lifter, a detection unit configured to determine the amount of misalignment of the product in the conveying direction and/or the width direction that is orthogonal to the conveying direction, while the product is being conveyed by the conveying unit, and a control unit configured to control the devices in the system to perform in accordance with the amount of misalignment.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
   This application claims priority to Japanese Patent Application Nos. 2005-161047 and 2006-051540. The entire disclosure of Japanese Patent Application Nos. 2005-161047 and 2006-051540 is hereby incorporated herein by reference. 
   BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   The present invention relates to a packaging system configured to package a product by covering the top surface of the product with a film. 
   2. Background Information 
   In conventional practice, some packaging systems package products with films by means of raising a container, such as a tray or the like, having a product contained therein onto a packaging station arranged thereabove. One example of such a packaging system is shown in  FIGS. 8 and 9 . 
   When a product M is placed on a tray supply device  20  shown in  FIG. 8  by an operator, the rear end Tb of the tray (container) T carrying the product M is pushed by a conveying bar (contact member)  13 , and the tray T is conveyed onto a lifter  201 . The posts  210  of the lifter  201  are disposed directly beneath the packaging station S of a packaging unit  200 . The posts are capable of being raised and lowered by a hoisting device  208 . The lifter  201  lifts the product M up to the packaging station S when the product M is supplied from the tray supply device  20  thereto. 
   Before the packaging operation, a film F cut to a specific length is supplied to and stretched over the packaging station S in  FIG. 9A  by a film supply device  202  (shown in  FIG. 8 ). This film F adheres to the top surface of the product M when the product M is pressed upward. In this state, a film folding unit  203  packages the product M by folding the edges on all four sides of the film F onto the bottom side of the tray T with a pair of left and right folding plates  204 ,  204 , a rear folding plate  205 , a rod-shaped front folding member  206 , and a pusher  207  (shown in  FIG. 8 ), and the packaged product M is ejected onto an ejecting conveyor  209  shown in  FIG. 8 . 
   However, the tray T may be somewhat misaligned to the left or right because it is placed on the tray supply device  20  by an operator. In order to solve this problem in this type of conventional packaging system, as disclosed in Japan Patent Application Publication 2001-48109 (particularly  FIG. 5  thereof), the amount by which the tray T is misaligned in the width direction on the tray supply device  20  is determined, and this widthwise misalignment is corrected in order to improve the finished state of packaging. 
   In a conventional packaging system, as shown in  FIG. 6A , the tray T is photographed from above by a camera when the tray T is placed on the tray supply device  20  (shown in  FIG. 8 ). The amount of misalignment from the center of the tray T is calculated based on this photograph information. After the photographing, the tray T is conveyed by a conveying bar  13 , as shown in  FIG. 6B , and then the tray T is moved towards the center by a movement unit (not shown in the figures) according to the amount of misalignment, as shown in  FIG. 6C . 
   However, sometimes the amount of misalignment changes when the conveying bar contacts with the tray, due to factors such as the weight of the materials to be packaged, the center of gravity, and the friction between the underside of the tray and the scale tray, even if the tray is positioned in the same manner and at the same position. For example, when the tray T is placed so as to be tilted with respect to the conveying bar  13 , as shown in  FIGS. 6D and 6E , the amount of post-conveyance misalignment of the tray T after it is conveyed and in contact with the conveying bar  13  may differ from the calculated misalignment, as shown in  FIGS. 6D and 6E . Therefore, sometimes the misalignment cannot be sufficiently corrected, even if the tray T is moved towards the center in accordance with the amount of misalignment determined by the camera. 
   Thus, sometimes the misalignment in the width direction, which is substantially orthogonal to the conveying direction of the products, cannot be resolved from the time conveying is initiated by the conveying unit until the time conveying is completed. 
   An inadequately corrected misalignment sometimes brings about a misalignment in the position of the product during packaging or a misalignment in the label attachment position. As a result, packaging is unsatisfactory, or the attachment position is misaligned. In addition, a large misalignment may even cause the tray T to be crushed. 
   Furthermore, misalignment can also occur in the conveying direction of the product. 
     FIGS. 7A-7H  are schematic side views showing the vicinity of the tray supply device  20  and a lifter  201 .  FIGS. 7A and 7B  show a normal conveying state of the tray T. The tray T shown in  FIG. 7A  is pushed by the conveying bar  13 , and is conveyed onto the lifter  201  as shown in  FIG. 7B . The position (stopping position) of the end of the advancing movement of the conveying bar  13  is set in advance for each tray T, and the tray T is pushed and conveyed to a specific position on the lifter  201  according to this set stopping position. 
   However, in cases such as when a tray T carrying a product is light in weight, as shown in  FIGS. 7C and 7D , the conveying bar  13  sometimes slips underneath the tray T, and the tray T will not be conveyed to the specified position on the lifter  201  even if the conveying bar  13  stops at the set stopping position. 
   In addition, if the tray T is deep, as shown in  FIGS. 7E and 7F , the conveying bar  13  sometimes slips in underneath the edge of the tray T, and the tray T will not be conveyed to the specified position on the lifter  201 . 
   In view of the above, it will be apparent to those skilled in the art from this disclosure that there exists a need for an improved packaging system. This invention addresses this need in the art as well as other needs, which will become apparent to those skilled in the art from this disclosure. 
   SUMMARY OF THE INVENTION 
   The packaging system of the present invention can be applied to a packaging device that uses stretched films or the like. 
   A primary object of the present invention is to provide a packaging system that is capable of packaging products based on the amount of misalignment that occurs in the conveying direction of the product and the width direction of the product after the product is conveyed. 
   In the invention disclosed in Japan Patent Application Publication No. 2001-48109, when the misalignment of the product is corrected, the conveying surface itself is moved in the width direction of the product according to the amount of misalignment of the product. Since the conveying surface is accommodated within the main body frame of the packaging system, the product sometimes protrudes past the outside of the conveying surface and cannot be conveyed in a stable manner when the product is too wide, or when the amount of misalignment in the width direction is too great. Moreover, since there is a natural limit to the moveable range of the conveying surface in the width direction, the amount of misalignment of the product cannot be corrected to a great extent. 
   Therefore, another object of the present invention is to provide a packaging system that can convey products in a more stable manner, and is capable of correcting a large amount of misalignment. 
   In order to achieve these objects, the packaging system according to a first aspect of the present invention is a packaging system configured to package a product by supplying a product onto a lifter by means of a supply device, pushing the product on the lifter up to a packaging station, and covering the top surface of the raised product with a film. The packaging system comprises a conveying unit that contacts the rear end in the conveying direction of a product on the supply device and configured to convey the product onto the lifter, a detection unit configured to determine the amount of misalignment in the conveying direction and/or the width direction that is orthogonal to the conveying direction of the product, while the product is being conveyed by the conveying unit, and a control unit configured to control the devices in the system to perform in accordance with the amount of misalignment detected. 
   According to the first aspect, it is possible to determine the misalignment of a product, including the misalignment that did not exist before the product began to be conveyed, or, in other words, the misalignment that occurs as a result of the product being conveyed. Therefore, a highly precise positioning of the product is possible because the final amount of misalignment of the product will be detected after the conveyance of the product begins. 
   According to the first aspect, in situations in which the amount of misalignment in the width direction is detected, it is preferable that the detection unit also determine the amount of misalignment of the product in the width direction after the product is placed on the supply device and before the product begins to be conveyed. 
   The initial amount of misalignment of the product can thereby be quickly detected, immediately after the product is placed, and therefore, it is possible to quickly respond to the misalignment of the product. In addition, a highly precise positioning of the product is possible, because the final amount of misalignment of the product is detected after the conveyance of the product begins. 
   According to the first aspect, in situations in which the misalignment in the width direction is corrected, it is preferable that the packaging system further comprises a moving unit that is configured to move the position of the product on the supply device in the width direction, wherein the control unit drives the moving unit to move the position of the product in accordance with the amount of misalignment in the width direction as detected by the detection unit, to correct the misalignment of the product in the width direction. 
   As a result, a well finished packaging can be expected because it is possible to correct a misalignment in the width direction that occurs after the conveyance of the product begins. 
   According to the first aspect, the packaging system may include a film supply device configured to convey the film in the width direction of the product, wherein the control unit drives the film supply device to convey the film according to the amount of misalignment in the width direction as detected by the detection unit, and stretches the film to a position in the width direction corresponding to the misalignment of the product. 
   As a result, a well finished packaging can be expected because the film supply position can be adjusted according to the misalignment in the width direction that occurs after the conveyance of the product begins. 
   According to the first aspect, when the product includes a tray, the type of tray may be identified by the system after the tray begins to be conveyed. 
   The precision in identifying the tray is thereby improved, because the tray is identified after the position of the tray is corrected, and after conveyance has started. 
   According to the first aspect, it is preferable that the control unit drive the conveying unit to convey the product in accordance with the amount of misalignment in the conveying direction as detected by the detection unit, and correct the misalignment of the product in the conveying direction. 
   As a result, a well finished packaging can be expected because it is possible to correct the misalignment in the conveying direction that occurs after the conveyance of product has started. 
   According to the first aspect, in situations in which the amount of misalignment in the conveying direction is detected, it is preferable that the detection unit detects the position of a contact member that comes into contact with the rear end of the product and the position of the rear end of the product, and detects the amount of misalignment of the product in the conveying direction based on the detected positional relationship between the contact member and the rear end of the product. 
   The product can thereby be supplied to a specific position on the lifter because even if relative misalignment occurs between the contact member and the product, the misalignment thereof will be detected. 
   According to the first aspect, the packaging system may further include a label attaching device configured to attach a label to a packaged product, wherein the position where the label is to be attached by the label attaching device is controlled by the control unit, and the label is attached to a position in accordance with the amount of misalignment of the product in the conveying direction and/or the width direction, as detected by the detection unit. 
   As a result, the label can still be attached to the correct position even if the product is misaligned. 
   The packaging system according to a second aspect is a packaging system configured to package a product by supplying a product onto a lifter, pushing the product on the lifter up to a packaging station, and covering the top surface of the raised product with a film. The packaging system comprises a first conveying surface on which a product is placed; a second conveying surface that is provided downstream of the first conveying surface and formed separately from the first conveying surface, and capable of moving within a specific range in a first or a second width direction that is substantially orthogonal to the conveying direction of the product; a conveying unit configured to convey the product from the first conveying surface onto the lifter through the second conveying surface; a detection unit configured to determine the direction of misalignment and the amount of misalignment of the product in the width direction on the first conveying surface; a moving unit configured to move the position of the product on the second conveying surface in the width direction by moving the second conveying surface in the width direction within the moveable range; and a control unit configured to drive the moving unit to pre-move the second conveying surface in a first or a second width direction in accordance with the direction and amount of misalignment in the width direction detected by the detection unit before the product is conveyed onto the second conveying surface, and also to move the second conveying surface in a first or a second width direction that is opposite the pre-moved width direction after the product has been conveyed onto the second conveying surface, to correct the misalignment of the product in the width direction. 
   It is possible to correct a considerable misalignment of a product in the width direction on the first conveying surface, by moving the second conveying surface in the width direction in advance. An excellent packaging finish can therefore be expected. 
   In a second embodiment of the present invention, the width of the second conveying surface is smaller than the width of the first conveying surface. 
   Since the second conveying surface is moved in advance according to the misalignment of the product, the entire product is transferred onto the second conveying surface when the product is transferred from the first conveying surface to the second conveying surface, even if the width of the second conveying surface is smaller than the width of the first conveying surface. Therefore, an excellent packaging finish can be expected because the position of the product is not disoriented while the product is being conveyed. 
   In another preferred embodiment of the present invention, the conveying unit comprises a first conveying unit that is in contact with the rear end of the product on the first conveying surface and configured to convey the product in the conveying direction, and a second conveying unit configured to move the second conveying surface along a direction orthogonal to the conveying direction, wherein the second conveying speed of the second conveying unit is set to a greater value than the first conveying speed of the first conveying unit. 
   In this embodiment, since the conveying speed of the second conveying surface is greater than that of the first conveying surface, the product on the second conveying surface is separated from the first conveying unit that pushes on the rear end of the product. Frictional force is therefore unlikely to act between the rear end of the product and the first conveying unit when the product is displaced in the width direction. Therefore, an excellent packaging finish can be expected because the position of the product is not likely to be disoriented. 
   These and other objects, features, aspects and advantages of the present invention will become apparent to those skilled in the art from the following detailed description, which, taken in conjunction with the annexed drawings, discloses a preferred embodiment of the present invention. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     Referring now to the attached drawings which form a part of this original disclosure: 
       FIG. 1  is a schematic perspective view showing a weighing, packaging, and pricing device in a packaging system according to a first embodiment of the present invention; 
       FIG. 2  is a partial cross-sectional, schematic perspective view showing the structure of the supply device; 
       FIG. 3  is a partial cross-sectional, schematic perspective view showing a correcting conveyor; 
       FIG. 4A  is a schematic structural view of the system, and  FIGS. 4B and 4C  are tables showing the stored content of a storage unit; 
       FIG. 5A  is a schematic view showing a method for determining the amount of misalignment of the tray, and  FIG. 5B  is a plan view of the correcting conveyor; 
       FIGS. 6A through 6C  are schematic plan views showing a conventional method of conveying a product,  FIGS. 6D and 6E  are schematic plan views showing the manner in which the position of the product is misaligned during conveying, and  FIGS. 6F through 6I  are schematic plan views showing a detection method of the present invention; 
       FIGS. 7A through 7H  are schematic elevation views showing the manner in which a product on the supply device is conveyed; 
       FIG. 8  is a schematic section view showing an example of a packaging unit; 
       FIGS. 9A and 9B  are schematic perspective views showing an example of a packaging method; 
       FIGS. 10A and 10B  are plan views showing a tray and a film used in a system according to a second embodiment of the present invention; 
       FIG. 11  is a partial cross-sectional, schematic perspective view showing the structure of a supply device in a packaging system according to a third embodiment of the present invention; 
       FIG. 12  is a partial cross-sectional view of a conveyor; 
       FIGS. 13A and 13B  are schematic plan views showing the manner in which the position of a product is disoriented when the product is conveyed from a first conveying surface to a second conveying surface; 
       FIGS. 14A and 14B  are schematic plan views showing the manner in which a product is conveyed smoothly from the first conveying surface to the second conveying surface; and 
       FIGS. 15A and 15B  are elevation views showing a modification of the conveying bar. 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
   Selected embodiments of the present invention will now be explained with reference to the drawings. It will be apparent to those skilled in the art from this disclosure that the following descriptions of the embodiments of the present invention are provided for illustration only and not for the purpose of limiting the invention as defined by the appended claims and their equivalents. 
   First Embodiment 
     FIG. 1  shows a weighing, packaging, and pricing device in a packaging system in accordance with a first embodiment of the present invention. The weighing and packaging units of this device are somewhat similar to those in the conventional packaging system shown in  FIG. 8 , and thus only the components of the present invention that are different from this conventional packaging system will be described below. The following description relates to a situation in which a product M is conveyed after being placed on a tray T. The term “product M” includes both the tray T and the contents included therein. 
   In  FIG. 1 , the weighing, packaging, and pricing device is provided with a tray supply device  20  that protrudes forward from the main body thereof. As shown in  FIG. 2 , the tray supply device  20  comprises a weighing conveyor  100  and a correcting conveyor (moving unit)  21 . A label attaching device  12  configured to attach a label to a packaged product M is provided above the ejecting conveyor  209  in  FIG. 1 . 
   The weighing conveyor  100  shown in  FIG. 2  comprises a resin plate  105  that forms a first conveying surface  102 , a conveying bar  13  configured to convey the tray T on the first conveying surface  102 , and a drive motor  16  (shown in  FIG. 4A ) and a driving chain  104  configured to drive the conveying bar  13 . Therefore, the conveying bar  13 , the drive motor  16 , and the driving chain  104  constitute part of the first and second conveying units for conveying the product M onto the lifter  201 . 
   In the weighing conveyor  100 , the resin plate  105  that forms the first conveying surface  102  is supported on a weight determining unit (loading cell)  101  shown in  FIG. 4A . The weight detected by the weight determining unit  101  is outputted to weighing unit  106  and inputted to a microcomputer (control unit)  3 . 
   The correcting conveyor  21  is provided downstream of the resin plate  105  of the weighing conveyor  100  shown in  FIG. 2 . This correcting conveyor  21  comprises a conveyor (part of the second conveying unit)  22  and a cam unit (part of the moving unit)  23 , as shown in  FIG. 3 . The conveyor  22  forms a second conveying surface  22   a.  The conveyor  22  is arranged to freely move in the width direction Y orthogonal to the conveying direction X of the product M while the movement of the conveyor  22  in the conveying direction X is restricted, and the conveyor  22  is supported by the cam unit  23 . 
   The cam unit  23  comprises a cam groove  23   a  formed on a flat panel, and an engaging pin  23   b  that slidably engages with the cam groove  23   a  . The engaging pin  23   b  is coupled with the output axle  26  of a motor  25  via a drive arm  24 . In the cam unit  23 , the engaging pin  23   b  slides within the cam groove  23   a  as the engaging pin  23   b  rotates in the directions shown by the arrows, corresponding to the rotation of the motor  25  rotating in a forward and backward direction, which moves the conveyor  22  in the width direction Y. The movement of the conveyor  22  causes the position of the product M on the tray supply device  20  to move in the width direction Y. 
   Control Configuration 
     FIG. 4A  shows the control configuration of this packaging system. 
   The microcomputer (control unit)  3  is equipped with a CPU  4  and a memory  5 . A touch screen  10 , a keyboard unit  11 , a label printer  12 , and a weighing, packaging, and pricing control unit  14  are connected to the microcomputer  3 . In addition, a CCD camera (part of the detection unit)  2  and the weighing unit  106  are connected to the microcomputer  3 . 
   The CCD camera  2  is arranged above the first conveying surface  102  as shown in  FIG. 2 , and almost the entire first conveying surface  102  is in view thereof. As shown in  FIG. 6F , when the product M (tray T) is placed on the first conveying surface  102  by an operator, the weight determining unit  101  detects a change in weight, which triggers the camera  2  to photograph the product M, and a first video signal is outputted to the microcomputer  3  (shown in  FIG. 4A ). 
   Then, as shown in  FIGS. 6G and 6H , the camera  2  photographs the conveyed product M again when the product M is conveyed to a specific position by the conveying bar  13 , and a second video signal is outputted to the microcomputer  3  in  FIG. 4A . 
   Misalignment Correction in Width Direction Y 
   The CPU  4  of the microcomputer  3  in  FIG. 4A  calculates the amount of misalignment in the width direction Y of the product M with the method described below. 
   The CPU  4  comprises an image processing unit  40 , a first and a second misalignment calculating unit  41  and  42 , and the like in the interior thereof. The image processing unit  40  locates the two edges Te, Te of the product M (tray T) in  FIG. 5A  in the width direction Y based on the video signals inputted from the CCD camera  2 . The first misalignment calculating unit  41  detects the amount of misalignment of the product M by finding the distances Y 1  and Y 2 , from the edge Te and edge Te to the center reference line C respectively, and subtracting the distance Y 2  from the distance Y 1 . 
   The amount of misalignment is calculated for both the first and second video signals. 
   The memory  5  shown in  FIG. 4A  comprises a product information storage unit  50 , a tray information storage unit  51 , and a reference value storage unit  52 . 
   A reference value YS is stored in the reference value storage unit  52 . Based on the first video signal, the CPU  4  moves the correcting conveyor  21  from its original position in advance when the first amount of misalignment calculated by the first misalignment calculating unit  41  is equal to or greater than the reference value YS, for example, 25 mm. 
   Subsequently, a second photograph is then taken when the product M is conveyed to a specific position by the conveying bar  13 . 
   The CPU  4  moves the correcting conveyor  21  shown in  FIG. 5B  to the left or right (in the width direction Y) to correct the misalignment of the product M, according to the second amount of misalignment calculated by the second misalignment calculating unit  42  based on the second video signal. Specifically, the motor  25  rotates only a rotation angle corresponding to the amount of misalignment to move the correcting conveyor  21  carrying the product M in the width direction Y, and correct the misalignment of the product M in  FIG. 5A  in the width direction Y. 
   Misalignment Correction in Conveying Direction X 
   The conveying bar  13  is driven by a drive motor  16  provided with a rotary encoder (part of the detection unit)  15  shown in  FIG. 4 , for example. The position of the conveying bar  13  is calculated by the CPU  4  based on a detection signal (rotation signal) from the rotary encoder  15 . Meanwhile, the rear end Tb of the product M (tray T) is detected by the camera  2 , as shown in  FIG. 7G . 
   The second misalignment calculating unit  42  is included in the CPU  4 . The second misalignment calculating unit  42  detects the amount of misalignment of the product M in the conveying direction based on the positional relationship between the conveying bar  13  and the rear end Tb of the product M. 
   The conveying bar  13  herein sometimes slips in underneath the product M while the product M is being conveyed, as shown in  FIGS. 7D and 7F . In such cases, the position of the conveying bar  13  differs from the position of the rear end Tb of the product M. 
   The second misalignment calculating unit  42  compares the position of the rear end Tb of the product M, as detected based on the second video signal from the camera  2 , with the position of the conveying bar  13  at the time the photograph was taken, as shown in  FIG. 7G , and calculates the amount of misalignment Δx in the conveying direction X. As shown in  FIG. 7H , the CPU  4  moves the front end of the conveying bar  13  forward by the distance of Δx according to the amount of misalignment Δx in the conveying direction X, whereby the product M is conveyed to a specific position on the lifter  201 , and the misalignment in the conveying direction X is corrected. 
   Specifying the Tray T 
   Referring to  FIG. 4A , the product information storage unit  50  stores the product name, the price, the position where the label is attached, and other such information, as well as the scheduled tray number to be used, for each product, according to the access number of the product in  FIG. 4B . In addition, the size of the tray T, including the width and depth of the tray T, is stored for each type of tray T in the tray information storage unit  51 , shown in  FIG. 4C . 
   The CPU  4  identifies the type of tray T based on the second video signal of the product M, after the product M has begun to be conveyed. The size information corresponding to the tray T and other such information is read by the CPU  4  from the tray information storage unit  51  according to the type of tray T identified. 
   Operation Description 
   Next, the operation and the manner in which the system is used will be described. 
   First, the operator inputs the access number of the product and other such information from the touch screen  10  and the keyboard unit  11  shown in  FIG. 1 . The operator then places the tray T (product M) having contents therein on the first conveying surface  102  of the tray supply device  20 , as shown in  FIG. 2 . When the product M is in place, a weight signal is outputted from the weighing unit  106 , shown in  FIG. 4A , to the microcomputer  3 . When the weight signal stabilizes, a first video signal is sent from the CCD camera  2  to the image processing unit  40 . 
   Then, the first misalignment calculating unit  41  calculates the amount of misalignment (Y 1 −Y 2 )=Δy 1  of the product M, as shown in  FIG. 4A , in the width direction Y, and compares the absolute value of the amount of misalignment (Y 1 −Y 2 ) with a reference value YS. The CPU  4  outputs a first correction command and a first misalignment amount Δy 1  to the weighing, packaging, and pricing control unit  14  when the absolute value of the amount of misalignment (Y 1 −Y 2 ) is equal to or greater than the reference value YS. 
   When the first misalignment amount (initial misalignment amount) Δy 1  exceeds a specific amount, the motor  25  is rotated to move the correcting conveyor  21  in advance by a distance equal to Δy 1  in the direction opposite the correcting direction. This makes it possible to accommodate even greater amounts of misalignment. 
   After the weight signal is stabilized, the driving chain  104  in  FIG. 2  is driven according to a specific sequence, and the conveying bar  13  begins to push on the product M. When the conveying bar  13  reaches a specific position P, the camera  2  photographs the product M, and a second video signal is sent to the image processing unit  40 . The second misalignment calculating unit  42  calculates a second misalignment amount Δy 2  and compares the absolute value of the second misalignment amount Δy 2  with the reference value YS. The CPU  4  outputs a second correction command and the second misalignment amount Δy 2  to the weighing, packaging, and pricing control unit  14  when the absolute value of the second misalignment amount Δy 2  is equal to or greater than the reference value YS. 
   In addition, the CPU  4  identifies the type of tray T based on the second video signal, which is taken after the orientation of the tray T has been corrected by the pushing of the conveying bar  13 . The CPU  4  obtains the size information and other such information corresponding to the tray T from the tray information storage unit  51 , according to the type of tray T identified. 
   The product M is transferred from the first conveying surface  102  onto the second conveying surface  22   a  of the correcting conveyor  21 . When the product M has been completely transferred onto the correcting conveyor  21 , the misalignment of the product M is corrected as follows. 
   Specifically, the weighing, packaging, and pricing control unit  14  to which the correction commands are inputted rotates the motor  25 , shown in  FIG. 3 , by a rotation angle corresponding to the second misalignment amount (the final misalignment amount). The drive arm  24  and the engaging pin  23   b  rotate in accordance with the rotation of the motor  25 , the conveyor  22  moves a certain amount in the width direction Y, and the misalignment of the product M in the width direction Y is corrected. 
   The second conveying surface  22   a  is herein moved by a distance equal to Δy 2  when the first misalignment amount Δy 1  is less than the reference value YS, and the second misalignment amount Δy 2  is greater than the reference value YS. On the other hand, when both the first and second misalignment amounts Δy 1  and Δy 2  are greater than the reference value, the second conveying surface  22   a  is moved by a distance equal to (Δy 2 −Δy 1 ). 
   The misalignment in the conveying direction X is also corrected while the product M is being conveyed. 
   The second misalignment calculating unit  42  calculates the position of the rear end Tb of the product M based on the second video signal processed by the image processing unit  40 . The second misalignment calculating unit  42  also calculates the position of the conveying bar  13  based on a signal from the rotary encoder  15 . The second misalignment calculating unit  42  compares the position of the rear end Tb of the product M with the position of the conveying bar  13 , and calculates the amount of misalignment in the conveying direction X. The CPU  4  moves the front end of the conveying bar  13  forward by a distance of Δx according to the misalignment amount Δx in the conveying direction X, as shown in  FIG. 7H . As a result of this operation, the product M is conveyed to a specific position on the lifter  201 , and the misalignment in the conveying direction X is corrected. 
   The product M, shown in  FIG. 2 , is pushed by the conveying bar  13  and transferred onto the lifter  201 . The specific packaging operation described above is then performed. Meanwhile, the correcting conveyor  21  returns to its original position. 
   Second Embodiment 
   In the first embodiment of the present invention, the misalignment was corrected by moving the product M according to the amount of misalignment of the product M. In the second embodiment of the present invention, the product M is not moved, instead, the film F is moved in the width direction Y of the product M according to the amount of misalignment of the product M. 
   As shown in  FIG. 10A , the product M is conveyed while the misalignment thereof from the center line CY (reference line C) in the width direction Y of the lifter  201  remains uncorrected. The CPU  4  calculates the final amount of misalignment of the product M based on the second video signal that is photographed by the camera  2 . The CPU  4  drives the film supply device  202  (shown in  FIG. 8 ) according to the amount of misalignment, and moves the film F to a position (shown by the dashed line in  FIG. 10A ) in the width direction Y according to the misalignment of the product M. 
   Then, as shown in  FIG. 10B , a label L is attached by a label attaching device  12  (shown in  FIG. 1 ) to the top surface of the product M that is wrapped by the film F. According to the amount of misalignment of the product M, the transverse distance Ly of the label L, which is the distance from the edge Te of the product M to the attached position, is changed. Moreover, the longitudinal distance Lx of the label, which is the distance from the rear end Tb of the product M to the attached position, is also changed. Specifically, the horizontal distance Ly is calculated by adding the amount of misalignment of the product M in the width direction Y to a pre-set distance Ly. Similarly, the longitudinal distance Lx is calculated by adding the amount of misalignment of the product M in the conveying direction X to a predetermined distance. 
   Third Embodiment 
   Referring now to  FIGS. 11 to 14 , a packaging system in accordance with a third embodiment will now be explained. The third embodiment of the present invention is largely similar to the first embodiment of the present invention, shown in  FIGS. 1 through 9 , in terms of the configuration, function, and operation thereof. 
   In  FIG. 11 , the correcting conveyor  21  is comprised of a moving plate  29  arranged below a conveyor belt  21   b  that constitutes the second conveying surface  22   a.  A cam groove  23   a , similar to the one in  FIG. 3 , is formed in the moving plate  29 , whereby the moving plate  29  is capable of moving in the width direction Y. 
   Specifically, the second conveying surface  22   a  is provided downstream of the first conveying surface  102  in order to convey the product M received from the first conveying surface  102  to the lifter  201 . The second conveying surface  22   a  is formed separately from the first conveying surface  102 , and configured to be movable within a specific range in the first and second width directions Y 11  and Y 12  that are substantially orthogonal to the conveying direction X of the product M. The width of the second conveying surface  22   a  is smaller than the width of the first conveying surface  102 . However, the size of the moveable range of the second conveying surface  22   a  is approximately corresponds to the width of the first conveying surface  102 . The moving unit  23  displaces the position of the product on the second conveying surface  22   a  in the width direction Y by moving the second conveying surface  22   a  in the width direction Y within the moveable range. 
   As shown in the cross section in  FIG. 12 , the moving plate  29  has a curved cross section, and comprised of a supporting unit  29   a  having concave shape in the mid-section thereof and disposed below the correcting conveyor  21   b , and a pair of exposed parts  29   b  protruding to the left and right sides of the second conveying surface  22   a  and formed integrally with the supporting unit  29   a.  The top surfaces of the exposed parts  29   b  are formed to be slightly lower in height than the top surface of the second conveying surface  22   a , whereby the exposed parts  29   b  do not interfere with the conveying of the product M by the second conveying surface  22   a.    
   Fixing covers  28  are arranged at the left and right ends of the moving plate  29 . The ends of the exposed parts  29   b  and the ends of the fixing covers  28  overlap each other, even when the correcting conveyor  21   b  moves to the very left or very right end within the moving range, whereby the contents of the tray T will be prevented from falling under the conveyor  22 , shown in  FIG. 11 . 
   In accordance with the direction of misalignment and the amount of misalignment in the width direction Y as detected by the camera  2 , the microcomputer (control unit)  3  (shown in  FIG. 4A ) drives the moving unit  23  before the product M is conveyed onto the second conveying surface  22   a , and moves the second conveying surface  22   a  in advance in the first or second width direction Y 11 , Y 12 . The microcomputer  3  drives the moving unit  23 , after the product M has been conveyed onto the second conveying surface  22   a , and moves the second conveying surface  22   a  in the first or second width direction Y 11 , Y 12 , that is opposite the previous width direction, to correct the misalignment of the product M in the width direction. In the present embodiment, the misalignment of the product M is corrected regardless of the extent of the misalignment of the product M in the width direction Y. 
   The conveying unit conveys the product M from the first conveying surface  102  onto the lifter  201  via the second conveying surface  22   a.  The conveying unit is comprised of a conveying bar  13  that comes into contact with the rear end of the product M on the first conveying surface  102  and configured to convey the product in the conveying direction, a driving chain  104  (first conveying unit), and a motor  25  (second conveying unit) configured to move the second conveying surface  22   a  along the conveying direction Y. The second conveying speed V 2  of the second conveying unit is set to a higher value than the first conveying speed V 1  of the first conveying unit. 
   Before describing the operation of the supply device according to the present embodiment, the disadvantages in the case that the second conveying surface  22   a  is not moved in advance, but rather, the second conveying surface  22   a  is moved in the width direction Y after the product M is conveyed onto the second conveying surface  22   a  will now be described. 
   As shown in  FIG. 13A , when the second conveying surface  22   a  is moved in the width direction Y after the product M placed on the first conveying surface  102  is conveyed onto the second conveying surface  22   a , the tray T sometimes could protrude in the width direction Y out of the second conveying surface  22   a , as shown by the dashed line. In this situation, the frictional conveyance force F applied by the second conveying surface  22   a  to the bottom surface of the tray T is misaligned with the center of gravity G of the product M. Therefore, a moment acts around the tray T, which prevents the tray T from being conveyed in a sufficiently stable manner, and easily results in the disorder of the orientation of the tray T, as shown in  FIG. 13B . 
   Next, the operation of the supply device  20  according to the third embodiment of the present invention will be described with reference to  FIG. 14 . 
   When the product M is placed on the first conveying surface  102 , as shown in  FIG. 14A , the distances Y 1  and Y 2  are determined with a specific timing. Moreover, the misalignment amount Δy in the width direction Y and the misalignment directions Y 11  and Y 12  are calculated by the method described in the first embodiment of the present invention. Based on the calculated results, the second conveying surface  22   a  moves in the width direction Y by a distance equal to the amount Δy, which is the misalignment amount Δy of the product M in the direction of misalignment, as shown by the dashed line, before the downstream end of the product M or the center of gravity G of the tray T (generally the geometric center of the tray) is conveyed to the upstream end  22   b  of the second conveying surface  22   a.    
   When the position of the tray T is not tilted as shown in  FIG. 14B , the centers Tc and  21   c  of the tray T and the second conveying surface  22   a  in the width direction Y nearly align with each other as a result of the movement. 
   After the movement, when the tray T begins to be transferred onto the second conveying surface  22   a , as shown by the solid line in  FIG. 14B , or when the entire tray T is completely transferred onto the second conveying surface  22   a , the second conveying surface  22   a  moves in the direction opposite the previous movement direction by a distance equal to Δy, as shown by the dashed line. The centers of the tray T and the correcting conveyor  21  in the width direction thereby nearly align with each other, as shown by the dashed line. Specifically, the product M is centered. 
   Since there is no danger of the tray T protruding in the width direction Y out of the second conveying surface  22   a  during the transfer, there is also no danger of the tray T being tilted, like the situation shown in  FIG. 13B  that was previously described. In other words, a stable conveyance of the tray T can be expected, in which the tray T is conveyed without being tilted, as shown by the dashed line in  FIG. 14B . As a result, an excellent packaging finish can be expected. 
   However, since the pushing surface  13   f  of the conveying bar  13  shown in  FIG. 11  is formed in a comb-teeth pattern with many notches, if the tray is soft, the rear end of the tray T sometimes is caught in the gaps of the pushing surface  13   f  during the conveyance. Therefore, when the second conveying surface  22   a  moves in the width direction Y, there is a danger that the rear end of the tray T will be caught on the pushing surface  13   f  of the conveying bar  13 , which could disorient the position of the tray T, or the specific movement amount Δy in the width direction Y might not be achieved. 
   The same problem also occurs when the product M, after packaged with a film, is weighed and priced. More specifically, because the product M has already been packaged and the stretched film is highly viscoelastic, the rear end of the product M may adhere to the pushing surface  13   f , and with the frictional force, it may stick to the pushing surface  13   f . Therefore, there is a danger of the disorientation of the position of the product M, similar to the situation previous described. 
   Accordingly, in the present embodiment, the conveying speed V 2  of the conveyor  22  is set to a higher value than the conveying speed V 1  of the conveying bar  13 . Therefore, when the tray T begins to be transferred onto the second conveying surface  22   a  as shown by the solid line in  FIG. 14B , the rear end of the tray T begins to separate from the pushing surface  13   f  that is shown in  FIG. 11 . Therefore, there is no danger that the movement of the tray T in the width direction Y will be hindered by the comb tooth-shaped pushing surface  13   f.  In addition, there is no danger of the disorientation of the position of the product M or the specific movement amount Δy not achieved. As a result, an excellent packaging finish can be expected. 
   In the present embodiment, the misalignment amount Δy in the width direction, illustrated in  FIG. 14A , and the direction of misalignment may be determined only prior to the time the tray T is conveyed after it is placed on the conveyor, only after the tray begins to be conveyed, or both before and after the tray begins to be conveyed. 
   In addition, in this embodiment, there is no need to move the second conveying surface  22   a  by a distance corresponding to the entire misalignment amount Δy determined. For example, the misalignment may be corrected by first determining the first misalignment amount Δy 1  in the width direction on the first conveying surface  102  before the tray begins to be conveyed, and then determining the second misalignment amount Δy 2  in the width direction after the tray begins to be conveyed, and moving the second conveying surface  22   a  in one width direction Y in advance by an amount equal to Δy 1  before the tray T begins to be transferred onto the second conveying surface  22   a , and then moving the second conveying surface  22   a  in the other width direction Y (opposite the previous width direction) by a distance of (Δy 2 −Δy 1 ) after the tray T is transferred onto the second conveying surface  22   a.  In this case, the second conveying surface  22   a  is moved by a distance equal to Δy 2 , and returned to its original position after the misalignment is corrected. 
   Furthermore, the second conveying surface  22   a  may be moved twice in advance so as to accommodate both the two determined misalignment amounts Δy 1  and Δy 2 . Specifically, the second conveying surface  22   a  may be immediately moved in advance by a distance equal to Δy 1  after the first misalignment amount Δy 1  of the tray T is determined, and the second conveying surface  22   a  may be immediately moved in advance by a distance equal to (Δy 2 −Δy 1 ) after the second misalignment amount Δy 2  of the tray T is determined. 
   There is also no need for the tray to be completely centered. For example, the second conveying surface  22   a  may be moved in advance by a distance equal to only one of the determined misalignment amounts Δy 1  or Δy 2 . 
     FIGS. 15A and 15B  show the preferred shapes and structures of the conveying bar  13  that will prevent the tray from turning over. As shown in  FIG. 11 , the conveying bar  13  is rotatably driven by a driving chain  104  such as a roller chain, for example. Since a small gap is formed between the pins and rollers in the roller chain, the conveying bar  13  shown in  FIG. 15A  is rotated to slightly rise in the direction of the arrow R when encountering the gaps. In this case, the angle formed by the pushing surface  13   f  of the conveying bar  13  that pushes the tray T increases, and there is a danger that the tray T will be scooped up and overturned from underneath. 
   The conveying bar  13  shown in  FIG. 15A  is inclined in the conveying direction X, such that the top end  13   t  extends farther in the direction X than the bottom end  13   u.  Therefore, the danger that the tray T will be scooped up from underneath is thereby eliminated, even if the conveying bar  13  is slightly rotated so as to rise up in the direction of the arrow R. 
   The position of the center of gravity in the product M is sometimes off centered in the conveying direction X. In this case, there is a danger that the rear end Tb of the tray T shown in  FIG. 15B  will rise up in the direction U, and the product M will be overturned when the conveying bar  13  pushes the tray T. 
   In  FIG. 15B , an overhanging member  13   a  is fixed in place at the top end  13   t  of the conveying bar  13 . This overhanging member  13   a  protrudes from the top end  13   t  to a greater distance in the conveying direction X than the top end  13   t.  Therefore, it is possible to prevent the product M from being overturned even if the rear end Tb of the tray T rises up in the direction U. 
   Modification A 
   The amount of misalignment of the product M may be determined by aligning a plurality of reflective light quantity detectors in the width direction Y. 
   Modification B 
   In addition, in the first embodiment of the present invention, it is not necessary to move the conveyor  22  in advance according to the amount of misalignment of the product M in the width direction Y. Alternatively, the conveyor  22  may be moved in advance in the width direction according to the second misalignment amount. 
   Modification C 
   Moreover, in the first and third embodiments of the present invention, the second conveying surface  22   a  is formed on the surface of the belt of the conveyor  22 . However, the second conveying surface  22   a  may be formed on the surface of a resinous flat plate or a roller, or the like. Furthermore, the amount of misalignment of the product may be corrected by a guiding member or the like, instead of the conveyor  22 . 
   Modification D 
   In the first and third embodiments of the present invention, the position of the conveying bar  13  in the conveying direction X was specified by an encoder provided to the drive motor of the conveying bar  13 . However, the position of the conveying bar  13  may be specified by the rotational position of the driving chain  104 , or directly detected by using an optical sensor or the like. 
   Modification E 
   In addition, as another example of a packaging system to which the present invention is applied, instead of the folded packaging as exemplified in the previous embodiments, the present invention can also be similarly applied to a so-called top-sealing packaging device. One example of a top-sealing packaging device is the packaging device disclosed in U.S. Pat. No. 6,666,005. 
   General Interpretation of Terms 
   In understanding the scope of the present invention, the term “configured” as used herein to describe a component, section or part of a device includes hardware and/or software that is constructed and/or programmed to carry out the desired function. In understanding the scope of the present invention, the term “comprising” and its derivatives, as used herein, are intended to be open ended terms that specify the presence of the stated features, elements, components, groups, integers, and/or steps, but do not exclude the presence of other unstated features, elements, components, groups, integers and/or steps. The foregoing also applies to words having similar meanings such as the terms, “including”, “having” and their derivatives. Also, the terms “part,” “section,” “portion,” “member” or “element” when used in the singular can have the dual meaning of a single part or a plurality of parts. Finally, terms of degree such as “substantially”, “about” and “approximately” as used herein mean a reasonable amount of deviation of the modified term such that the end result is not significantly changed. For example, these terms can be construed as including a deviation of at least ±5% of the modified term if this deviation would not negate the meaning of the word it modifies. 
   While only selected embodiments have been chosen to illustrate the present invention, it will be apparent to those skilled in the art from this disclosure that various changes and modifications can be made herein without departing from the scope of the invention as defined in the appended claims. Furthermore, the foregoing descriptions of the embodiments according to the present invention are provided for illustration only, and not for the purpose of limiting the invention as defined by the appended claims and their equivalents.