| 摘要 |
<p>PURPOSE:To obviate the generation of errors even if track density increases by subjecting a magnetic layer to a thermal shrinkage treatment after forming to decrease the thermal shrinkage rate thereof to a specific value or below. CONSTITUTION:After the magnetic layer is formed on a synthetic resin film as a nonmagnetic base, this doughnut plate-shaped flexible magnetic disk is heat-treated. The magnetic disk is so formed that the thermal shrinkage rate of the diameter after holding for 64 hours in environment of 60 deg.C and 90% RH, then taking out into room temp. and resting for 72 hours is <=0.04%. The magnetic layers are preferably formed nearly equally on both surfaces of the synthetic resin film subjected to the shrinkage treatment. The synthetic resin film is preferably a polyethylene terephthalate film. The flexible magnetic disk which obviates the generation of the errors even if the track density increases is obtd. in this way.</p> |
