| 摘要 |
<P>PROBLEM TO BE SOLVED: To prevent a film welded part at a location where the number of film plies is changed from being damaged by the irregular portion of a linear welded part and at the same time prevents an excessive load from being applied to the linear welded part when a bag is opened or closed. <P>SOLUTION: A linear welded part (6) of a resin packaging bag (1) has, at the width-wise central part of the bag, only one irregular part (7) extending across inner folding-back edges (5) of the right and left gusset portions (4). The irregular part is composed of the right and left curved segments (7a) gradually curved from the linear portion of the linear welded part and a lower bulging-out segment (7b) formed between the right and left curved segments and gradually curved. The arcuate part of the lower bulging-out segment crosses the right and left inner folding-back edges. The linear welded part is formed by a heat roll sealing device having a heat sealing roll (11) and a film supporting roll (12) that are rotated in a synchronous manner. <P>COPYRIGHT: (C)2011,JPO&INPIT |
