Structure for preventing misinsertion of disc cartridges

A disc cartridge comprising:

• a shell shaped substantially like a flat rectangular parallelopiped, said shell having one side face and an opening;
• a shutter mounted to said shell, said shutter being slidable along said one side face between a first position where said shutter closes said opening and a second position where said shutter opens said opening;
• and
• a misinsertion preventing portion arranged with said one side face of said shell in a portion thereof out of a slide area of said shutter, formed at a corner of said one side face of said shell, and having a recess for allowing introduction of a misinsertion preventing member of a drive, a shape of said recess is substantially like a rectangular parallelopiped extending from said one side face of said shell to another side face of said shell, said misinsertion preventing portion includes a pair of side walls substantially perpendicular to said one side face of said shell, and a connecting wall for connecting said pair of side walls, whereby a corner portion is formed at said corner of said one side face of said shell, said corner portion has a base on the side of said connecting wall and a head on the side of said one end face of said shell, said base being larger in width than said head,
• wherein said one side face of said shell has a portion closed by said shutter upon shutter closing and facing outside upon shutter opening, said portion being of the same height in its entirety;
• and
• wherein said one side face corresponds to a front end face as viewed in a direction of insertion of the disc cartridge in said drive.