Tension gradient measurement of magnetic tape

Abstract

This paper describes a device that measures the tension distribution across the width of magnetic tape. Historically, tension variation along the length of the tape has been used to quantify data reliability, and accurate tension control with the use of vacuum column is necessary. The longitudinal tension gradient is the primary source of data error. Thick mylar and lower number of tracks per mm produce very little tension gradient across the width of the tape. Conditions due to the decrease in tape thickness, tape hub taper, alignment of the tape-device components, and high temperature and humidity of the tape environment, result in tape tension being no longer uniform across the width. A tension-measuring device was developed to aid in the understanding of the presence of tension gradient across the width of the tape and its resultant effects on uneven head wear and nonuniform data reliability. The use of this device led to improvements in tape-path component design, head wear, and data reliability.