| 摘要 |
PURPOSE:To improve the detecting accuracy for a tracking shift without using any new special parts by detecting the tracking shift after measuring the output value of an erasion head for correction which discontinues its demagnetizing action in a reading mode. CONSTITUTION:Gaps 2a and 2b never reach a track as long as the coincidence is obtained between a written track and the center line of a magnetic head 1. Therefore no output is obtained from a coil wound around an erasion head 2 for correction. While if the track position has a shift to the upper side, the track passes over the gap 2a to vary the density of the magnetic flux. Thus the coil delivers an output. When the track is shifted to the lower side, the coil delivers an output by the variation of the density of the magnetic flux of the gap 2b. Thus the degree of a tracking shift can be decided with high accuracy by measuring the output value of a track width correcting erason head which is incorporated with a read/write head. |
