Patent ID: 7136241

Claim:
An information writing device, comprising: a spindle motor including a spindle shaft provided for protruding on a substrate for causing rotation of a disc-shaped recording medium detachably mounted on the spindle shaft; a clock pattern disc including a clock track in which an optically readable clock pattern is recorded along the entire circumference thereof, said clock pattern disc being mounted on said substrate on the proximal side of said spindle shaft opposite said recording medium and being run in rotation by said spindle motor; an optical head for optically reading out said clock pattern on said clock pattern disc; a clock generator for generating clock signals based on electrical signals obtained on photoelectrically transducing a light output transmitted via an optical fiber, said light output corresponding to said clock pattern optically read out by said optical head; an information generating part for generating the information in a timed relation to the clock signals generated by said clock generator; a recording head for writing the information generated by said information generating part on said disc-shaped recording medium, run in rotation by said spindle motor; head driving means for causing movement of said recording head in a direction along the radius of said disc-shaped recording medium; and position controlling means for controlling said head driving means based on the information generated by said information generating part for causing movement of said recording head to a preset position on said disc-shaped recording medium and positioning said recording head at said preset position.