Magnetic tape driving mechanism having a capstan with a surface made of carbon film including diamond-bonded carbons

摘要

A tape driving mechanism for a magnetic recording apparatus has a capstan rotated to advance a magnetic tape by pinching the magnetic tape between the capstan and a pinch roller. The pinch roller is pressed onto the magnetic tape against the capstan. The capstan surface is coated with a diamond-like carbon film which is smooth and highly wear-resistant. The difference between the tangential speed of the capstan and the tape transfer speed is almost zero. Thus, the state of contact is static. A static frictional coefficient between the diamond-like carbon film of the capstan and the magnetic tape is almost equal to twice the static frictional coefficient between the metal surface of the capstan and the magnetic tape in the conventional tape driving mechanism. The tape driving force thus remains sufficient even if the pressure exerted by the pinch roller is reduced to half the value employed in the conventional tape driving mechanism. The diamond-like carbon film may be coated on a rough surface of the capstan.