Storage Bag Convex Coupling for Vertical Fold Suppression

The patent modifies the physical parameters of the coupling portion by adding convex portions that protrude into the bag body. These convex portions change the geometric parameters of the coupling region, creating a mechanical constraint that prevents vertical fold formation while maintaining the ability of the gusset to fold smoothly during ink usage. This parameter modification resolves the contradiction by simultaneously enabling smooth folding and ensuring complete ink consumption.

The convex portions act as intermediary elements within the coupling portion that mediate between the flexible gusset material and the folding action. These protrusions interfere with the formation of vertical folds by creating a mechanical barrier, while still allowing the gusset to fold smoothly in the intended direction. This intermediary structure eliminates the harmful vertical fold resistance without compromising the flexibility needed for smooth folding.