| 摘要 |
PURPOSE:To obtain a head feed device which is free from the S/N degradation of a reproduced signal and the crosstalk between tracks, by constituting a feed screw to expand or contract equally in quantity in the radius direction of a magnetic sheet in response to the temperature change. CONSTITUTION:A feed screw 4 uses a material which has the same linear expansion coefficient as a magnetic sheet 10. The sheet 10 expands or contacts in its radius direction and on the basis of its center O in response to a rise and a fall of the ambient temperature. At the same time, the screw 4 expands or cotacts in the radius direction of the sheet 10 on the basis of a reference position M set by the surface where a flange 4b coincident with the center O of the sheet 10 is brought into contact with a bearing 5. Thus a magnetic head 9 can move to the left or right by an extent equivalent to the expansion/contraction of the sheet 10. Thus it is possible to perform recording and reproducing without causing the S/N degradation nor increment of the crosstalk between tracks. |
