Patent ID: 7231646

Claim:
A disc drive unit for writing to and/or reading from a disc-shaped recording medium, which is rotatably housed inside a disc cartridge including a rotatably-housed inner rotor and a shutter which opens and closes a pick-up insertion slot from the inside by rotation of the inner rotor, said disc drive unit comprising: a rack member having a rack portion engaging with an outer peripheral gear formed on an outer periphery of said inner rotor; and driving means for slidably-driving said rack member with respect to said disc cartridge so as to rationally drive said outer peripheral gear; and a cartridge holder into which said disc cartridge is inserted; and locking means for locking said cartridge holder inserted into said cartridge holder in place inside the cartridge holder, wherein said driving means slidably drives said cartridge holder with respect to said rack member, which is fixed in position, so as to rotationally drive said inner rotor by means of said rack member.