Disk cartridge

A disc cartridge characterized by:

• a disc having at a center portion thereof a center core for being chucked by a drive mechanism, said disc being rotated at a speed higher than 3000 rpm when put on and driven by said drive mechanism;
• and
• a cartridge body having said disc rotatably installed therein,
• said cartridge body having at a center portion of a lower part thereof a center opening through which the center core is exposed to the outside of the cartridge body, and having at mutually facing portions of upper and lower parts thereof paired writing and/or reading apertures each extending radially outward to expose at least a part of the signal writing zone of the disc to the outside, and having a shutter member for opening and closing said writing and/or reading apertures, said shutter member having a generally U-shaped cross section, and having between the upper and lower parts thereof a partition wall which surrounds substantially entire periphery of the disc,
• said partition wall having a cut portion near said writing and/or reading apertures at a position downstream of said writing and/or reading apertures with respect to the rotation direction of the disc,
• said cut portion being connected through a discharge passage to a discharge opening formed in a front wall of the cartridge body,
• said discharge opening being located at position which is covered by the shutter member when the shutter member is in a position to close said writing and/or reading apertures, and
• said cartridge body being provided at inner surfaces of the upper and lower parts thereof with protection sheets, said protection sheets being bonded to the inner surfaces of the upper and lower parts, so that when the center core of said disc is chucked by the disc drive mechanism, the protection sheets are kept away from the disc without contacting the same.