Flat Heads for High-Speed, Contact Tape Recording: Experimental Evaluation and Theoretical Analysis

We report on an investigation of the mechanics and tribology of a flat head for high-speed, contact tape recording. We found that a self-acting negative air-bearing (suction) created near the leading wrapped corner is responsible for stable low-pressure contact over a wide range of speed, wrap angle, tension and tape thickness. This suction is caused by the expansion of air into the diverging gap on the upstream side of the head-tape interface which is unique to this wrap geometry. Experiments performed on a “row-bar” of thin film disk heads where the tape is wrapped only on the edge opposite to the heads showed the gap spacing to be stable in the 0.5–8m/s speed range with less than 4nm of wear on the read elements. A bi-directional version of a flat head geometry is analyzed via a model and suggestions are made for that design.