Bag packaging method

Abstract

A bag packaging method by which a mouth portion of a thin plastic-made bag filled with articles can be sealed without creases is provided. A bag 4 filled with sliced bread 1 is conveyed by a blade conveyor 6 . A mouth portion of the bag 4 is led between upper and lower two conveyor belts 20, 21 . While a suction force acting on upper and lower sides of the mouth portion is applied from vacuum chambers 23, 24 through the conveyor belts 20, 21 , air is blown from a sirocco fan 13 toward a mouth of the bag 4 so that the mouth portion of the bag 4 is opened. Two mouth spreader bars 30 having an interval between their distal ends narrowed are inserted into the bag 4 so opened. Then, the mouth spreader bars 30 have the interval widened to thereby spread the mouth portion flat. The mouth portion of the bag 4 spread flat is pinched and sealed by a sealer 50 without generation of creases.

1 . A bag packaging method comprising the steps of: 
 while causing a suction force to act on both sides, opposed to each other, of a mouth portion of a bag filled with articles, opening the mouth portion of said bag by blowing air toward a mouth of said bag,    inserting two mouth spreader bars having an interval between their distal ends narrowed into said bag so opened,    causing said mouth spreader bars to have the interval laterally widened to thereby spread the mouth portion of said bag flat, and    causing a sealer to pinch and seal the mouth portion of said bag so laterally spread.    
   
   
       2 . A bag packaging method as claimed in  claim 1 , wherein said step of causing the suction force to act on the both sides of said bag is carried out by leading the mouth portion of said bag between upper and lower two conveyor belts, each comprising an air suction means, arranged to run in a running direction of said bag with an interval maintained between said two conveyor belts.  
   
   
       3 . A bag packaging method as claimed in  claim 2 , wherein said two conveyor belts are arranged such that the interval between said two conveyor belts is gradually increased toward the running direction of said bag.  
   
   
       4 . A bag packaging method as claimed in  claim 1 , comprising the steps of: 
 causing an air squeezer to push the mouth portion of said bag so spread flat by said mouth spreader bars,    moving said bag relative to said air squeezer to thereby cause said air squeezer to squeeze air existing between the mouth of said bag and the articles filled in said bag to be discharged outside, and then    carrying out the sealing of the mouth portion of said bag.    
   
   
       5 . A bag packaging method as claimed in  claim 4 , comprising the step of: 
 carrying out the movement of said bag relative to said air squeezer by retraction of said mouth spreader bars as well as by pushing out a bottom portion of said bag to thereby carry out the discharge of said air.    
   
   
       6 . A bag packaging method as claimed in  claim 1 , comprising the steps of: 
 inserting an air suction pipe together with said two mouth spreader bars into said bag having the mouth so opened,    causing said air suction pipe to suck out air in said bag having the mouth portion so spread flat by said mouth spreader bars to be discharged outside, and then    carrying out the sealing of the mouth portion of said bag having the air so discharged outside.    
   
   
       7 . A bag packaging method as claimed in  claim 2 , comprising the steps of: 
 causing an air squeezer to push the mouth portion of said bag so spread flat by said mouth spreader bars,    moving said bag relative to said air squeezer to thereby cause said air squeezer to squeeze air existing between the mouth of said bag and the articles filled in said bag to be discharged outside, and then    carrying out the sealing of the mouth portion of said bag.    
   
   
       8 . A bag packaging method as claimed in  claim 7 , comprising the step of: 
 carrying out the movement of said bag relative to said air squeezer by retraction of said mouth spreader bars as well as by pushing out a bottom portion of said bag to thereby carry out the discharge of said air.    
   
   
       9 . A bag packaging method as claimed in  claim 2 , comprising the steps of: 
 inserting an air suction pipe together with said two mouth spreader bars into said bag having the mouth so opened,    causing said air suction pipe to suck out air in said bag having the mouth portion so spread flat by said mouth spreader bars to be discharged outside, and then    carrying out the sealing of the mouth portion of said bag having the air so discharged outside.