Cartridge packaging material and cartridge packaging structure

A cartridge packaging material in combination with a storage case that stores data recording cartridges, the storage case having first projecting portions that consist of first and second fitting ribs, each projecting from an upper surface of the storage case, and second projecting portions that consist of first and second fitting ribs, each projecting from a lower surface of the storage case, the cartridge packaging material comprising:

• a backing plate member formed by bending a sheet-shaped member so that it covers the upper surface, the lower surface and at least one side surface of the storage case, the backing plate member having first cutout portions, each for receiving the first projecting portion, and second cutout portions, each for receiving the second projecting portion;
• and
• an outer case for storing the storage case in a fitted state in which the backing plate member is along the first surface, the second surface and the at least one side surface of the storage case, wherein
• the two annular first fitting ribs and the two annular second fitting ribs are respectively disposed point symmetrically on diagonal lines passing the center of the upper surface of the storage case, each second fitting rib being larger than each first fitting rib, the second fitting rib being engageable with the first fitting rib, wherein
• the annular second fitting ribs and the annular first fitting ribs of the second projecting portions are disposed at positions of the lower surface of the storage case where the first fitting ribs and the second fitting ribs of the first projecting portions are respectively engageable, wherein
• when the plurality of storage cases are stacked, the first projecting portions and the second projecting portions are respectively engaged, wherein
• the backing plate member is formed of a sheet-shaped member consisting of at least three surfaces, which are a first surface which is along the upper surface of the storage case, and formed with the first cutout portions, a second surface which is along a bottom surface of the storage case, and formed with the second cutout portions, and a third surface foldably connecting with both the first surface and the second surface, and is along the at least one side surface of the storage case, wherein
• the first cutout portions of the first surface include first openings and second openings, the first openings being formed so that their positions and shape correspond to those of the first fitting ribs formed on the upper surface of the storage case, the second openings being formed so that their positions and the shape correspond to those of the second fitting ribs formed thereon, and the first projecting portions are constructed by the first fitting ribs and the second fitting ribs, wherein
• the second cutout portions of the second surface include first openings and second openings, the first openings being formed so that their positions and shape correspond to those of the first fitting ribs formed on the lower surface of the storage case, the second openings being formed so that their positions and the shape correspond to those of the second fitting ribs formed thereon, and the second projecting portions are constructed by the first fitting ribs and the second fitting ribs, wherein
• each second opening has a larger opening area than each first opening, and the first opening and the second opening are point-symmetrically disposed,
• the sheet-shaped member forming the backing plate member is corrugated cardboard, and
• a folding portion provided to fold the backing plate member into a plurality of surfaces is formed along a line extending in a direction perpendicular to corrugated ridge lines forming a core of the corrugated cardboard.