Abstract :
The characteristics of tape flight over the entire drum assembly were analyzed, taking tape-drum contact into consideration, and assuming a practical VCR drum system in which the lower drum is stationary. Through this analysis, the effects of the basic components of the tape/drum system were examined, with the following results: 1) By making the upper drum radius larger than that of the lower drum, the tape can be supported by the lubricated region of the upper drum, and contact between tape and lower drum can be reduced. However, contact between the tape and the upper drum edge occurs where the tape leaves the drum assembly. 2) When the tape is inclined at an angle (helical angle) with the direction of drum rotation, the tape flying height is reduced throughout, from where the tape meets the drum to where it leaves. Where the tape leaves the drum, the tape makes contact with the lower drum. 3) There is considerable in-plane stress in the tape where it is subjected to pressure. For this reason, in systems with a helical angle, stress in the tape tends to concentrate where the tape leaves the drum on the upper drum side. 4) The tape feed system, including the lead guide, affects not only the lateral position of the tape, but also the characteristics of tape glide over the drum.
