Differential Field, Erase-Gap Head for Dual Density Recording
Original Publication Date: 1985-Feb-01
Included in the Prior Art Database: 2005-Feb-18
Presented here is a design for a single head which will create an erase track either 3 mils wide or 9 mils wide. This simplified head design further has the significant advantage of being built exactly as heads are built today, except for one step in the manufacturing process. The key to the concept is the creation of an erase gap which will generate sufficient flux across one portion of the gap (3 mils) to overcome the coercivity of the disk in that area to cause erasure, but not enough flux to cause any significant erasure along the rest of the gap (6 mils). However, by increasing the current in the head, the flux across the entire gap will become sufficient to erase the entire width (9 mils).