| 摘要 |
<p>PURPOSE:To improve the quality of a picture by forming pump-out type spiral grooves on an area surrounded by a magnetic tape at the end surface of fixed cyinders opposed to the end surface of a rotary member and by forming pump-in type spiral grooves on the other area. CONSTITUTION:The rotary member 29 mounting a magnetic head 28 is arranged on the coaxial surface as a pair of fixed cylinders 30, 32 with gaps. When the rotary member 29 is turned in the direction of an arrow (a), external air is sacked from the pump-in type spiral grooves fromed on the area not opposed to the magnetic tape 37 into the inside of the cylinder through the gaps and the internal air is discharged from the pump-out type spiral grooves to th outside of the cylinder. The magnetic tape 37 prevents the air in the internal space of the cylinder from being discharged to the external, so that the atmospheric pressure in the internal space is made higher than that of the external and the magnetic tape 37 is floated.</p> |
