| 摘要 |
PURPOSE:To obtain a permanent magnet erasing head of gradient magnetic field type with stable performance without dispersion in magnetic field strength distribution, by alternately laminating a plurality of permanent magnets and nonmagnetic substances with different thickness and making magnetization toward laminating direction of the magnet plates. CONSTITUTION:Magnet plates 9, 10, 11 with different thickness and nonmagnetic substances 12 with different thickness are combined alternately for lamination and a tape sliding surface 1 is shaped. The assembly is clipped with magnetizing magnet poles 13 from both sides and magnetization is made by applying a DC magnetic field. A leakage magnetic flux shown in broken lines 14 appears at the surface 1. The magnetic flux density distribution measured toward the sliding surface shows an inverted gradient magnetic field distribution, and the leakage magnetic flux density at larger size ratio T/L of the magnet plate is increased and decreased at smaller size ratio T/L. As the thickness of the nonmagnetic substance 12, thicker substance is used at thicker magnet thickness at both sides clipping the nonmagnetic substance and thinner substance is used at thin magnet thickness. Thus, without dispersion in the magnetic field strength distribution, stable performance can be achieved. |
