| 摘要 |
PURPOSE:To attain the stable running of a tape along a lead by setting the friction resistance of a tape contact face of a lower cylinder larger than that of an upper cylinder. CONSTITUTION:For a rotary head cylinder 1, the outer circumference of the tape contact face of an upper cylinder 2 is formed by an arc-shaped cutting tool having a small tip form. While an arc-shaped cutting tool having a large tip form is used to form the outer circumference of the tape contact face of a lower cylinder 3. The angle (a) formed by the edge slope of the groove of the cylinder 2 and the tape width direction is larger than the angle (b) formed by the fringe slope of the groove of the cylinder 3. This increases the stable friction resistance between the cylinder 3 and a tape 5 and decreases the unsta ble friction resistance between the cylinder 2 and the tape 5 in terms of the friction resistance which acts on the tape 5. Thus the variance of the tension T of the tape 5 is reduced and therefore the descending force F which energizes the tape 5 to a read 4 is stabilized. Thus the stable running of the tape 5 is secured along the lead 4.
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