Process and apparatus for manufacturing packages

A process for manufacturing a package including a box body formed of a packaging material that is a soft sheet of a mono-layer or multi-layer structure having a resin film and a cover member for closing an opening of said box body, the process comprising the steps of:

• (a) folding the packaging material to form a box body including a rectangular bottom face portion and four side face portions that are folded from four sides of said bottom face portion and four triangular projecting portions projecting outward of the box body and folded into a triangular shape, wherein each triangular projecting portion has a corner portion between first and second side face portions adjoining to each other as one side of the triangular shape;
• (b) jointing said packaging material to itself in each triangular projecting portion while leaving a non-jointed portion of a smaller triangular shape having one side coinciding with said corner portion and another side extending in a plane flush with upper ends of said side face portions, so that each triangular projecting portion has a corner sealing portion in which said packaging material is jointed to itself along said corner portion and a jointed sealing portion in which said packaging material is jointed to itself to define a remaining side of the triangular non-jointed portion;
• (c) folding upper portions of said side face portions outward of the box body to form flange portions while simultaneously developing said triangular non-jointed portions planarly to form flange jointing portions that are flush with said flange portions;
• and
• (d) jointing a cover member to upper faces of said flange portions and said flange jointing portions.