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. While a bag 4 filled with articles is conveyed by a blade conveyor 6, at position opposed to a sirocco fan 13, air is blown from the sirocco fan 13 toward a mouth of the bag so that the mouth portion of the bag 4 is opened. Two mouth spreader bars 20 are moved to position in front of the bag 4 so opened. The mouth spreader bars 20 having an interval between them narrowed are inserted into the bag 4. Then, the mouth spreader bars 20 have the interval widened and are retracted. Thereby, the mouth portion is spread flat. Narrowing and widening of the mouth spreader bars 20 are done by cam followers 24 engaging with different cams while moving forward and backward. The mouth portion of the bag 4 spread flat is pinched and sealed by a sealer without generation of creases and folded and bound by a binder 60.

Description

BACKGROUND OF THE INVENTION [0001] 1. Field of the Invention [0002] The present invention relates to a bag packaging method for producing a bag package of articles by sealing a mouth portion of a thin soft plastic bag filled with articles. [0003] 2. Description of the Prior Art [0004] A bag packaging method for producing a bag package by filling articles in a plastic-made bag and then sealing a mouth portion of the bag is widely practiced. However, while such a bag packaging method is carried out for packaging using a thick and comparatively strong plastic bag, under the present circumstances, such method is not practically used for packaging using a thin soft plastic bag. [0005] The reason therefor is that once the thin soft plastic bag is filled with articles, even if the mouth portion thereof is wanted to be sealed, the bag is very soft and weak so that it is extremely difficult to seal the mouth portion without generation of creases. [0006] For example, in a marketed package usi...

AI Technical Summary

Benefits of technology

[0010] In view of the problems in the prior art, it is an object of the present invention to provide a bag packaging method by which a mouth portion of a thin plastic bag filled with articles to be packaged can be beautifully, securely and stably sealed without generation of creases.

[0012] According to the bag packaging method of the present invention, while the bag filled with articles is placed on the carrier conveyor and is being conveyed, air is blown toward the mouth of the bag and thereby the mouth portion of the bag is opened. Then, the two mouth spreader bars having the interval between them narrowed are inserted into the bag having the mouth so opened. By the mouth spreader bars having the interval laterally (horizontally) widened, the mouth portion of the bag is also laterally spread. Thus, the mouth portion of the bag filled with the articles is spread flat. This mouth portion of the bag so spread flat is pinched and sealed by the sealer. Hence, the mouth portion of the bag is beautifully sealed without generation of creases and a tight seal is realized.

[0013] In the bag packaging method according to the present invention, each of the mouth spreader bars comprises the cam follower and when the mouth spreader bars move forward and backward relative to the mouth of the bag, the cam follower engages with different cams so that the mouth spreader bars can simply and quickly have the interval between them laterally narrowed and widened, respectively. Thus, the insertion of the mouth spreader bars having the interval narrowed into the mouth portion of the bag and the retraction of the mouth spreader bars having the interval widened from the mouth portion of the bag can be quickly done and the bag packaging velocity can be largely increased.

[0014] In this way, according to the bag packaging method of the present invention, even if the bag is made of a very thin and weak plastic film, the mouth of the bag can be securely opened and by the mouth spreader bars inserted thereinto, the mouth portion of the bag is spread flat and can be securely and quickly sealed without generation of creases.

[0015] In the bag packaging method according to the present invention, it is preferable that an air squeezer pushes the mouth portion of the bag spread flat by the mouth spreader bars and this bag is moved relative to the air squeezer so that air existing between the mouth of the bag and the articles filled in the bag is squeezed to be discharged outside and then the sealing of the mouth portion is carried out. By so doing, there remains no surplus air in the bag after sealed and this contributes to maintaining the articles in the bag fresh.

[0017] Also, in the bag packaging method according to the present invention, it is preferable that an air suction pipe is inserted together with the mouth spreader bars into the bag having the mouth opened so that air in the bag having the mouth portion spread flat by the mouth spreader bars is sucked out by the air suction pipe to be discharged outside and then the sealing of the mouth portion is carried out. Thereby, no surplus air remains in the bag and this contributes to maintaining the articles in the bag fresh.

Problems solved by technology

However, while such a bag packaging method is carried out for packaging using a thick and comparatively strong plastic bag, under the present circumstances, such method is not practically used for packaging using a thin soft plastic bag.

The reason therefor is that once the thin soft plastic bag is filled with articles, even if the mouth portion thereof is wanted to be sealed, the bag is very soft and weak so that it is extremely difficult to seal the mouth portion without generation of creases.

Thus, as the mouth portion of the bag package using the thin plastic bag is not tightly closed by sealing, there is a problem that sweet smells come out of the bread or the like in the bag so that small insects are induced to enter the bag or dusts may come into the bag in the course of distribution.

Especially, while such small insects or dusts stick to the mouth portion of the bag, if the clip or tape binding the mouth portion is detached, there is a large possibility that the insects or dusts come into the bag.

However, the mouth portion of the bag is too weak to keep standing or, even if it is laid down, it is hardly spread flat without generation of creases.

Hence, sealing of the mouth portion is difficult.

However, in such sealing of the mouth portion, there are seen many shortcomings such that many creases are generated in the sealed portion of the bag mouth portion and heating for the sealing is not uniformly done because of the creases of the sealed portion so that the sealed portion may partially melt to be broken or the mouth portion may open because of the insufficient sealing.

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