To permit the production of a magnetic record medium which is magnetically isotropic by using spherical or substantially spherical magnetic particles to produce the medium.
Although spherical particles rotate a little by the influence of shear torque of a viscous fluid, no relation exists between the anisotropic axis and the direction of shear rotation because of the spherical shape. The other particles rotate in the different direction in a same amt. against the whole particles rotated in the prescribed direction. Therefore, a magnetically isotropic layer or a wholly magnetized card becomes an imaged supporting body. The magnetic force to hold the particles together owing to the point contact is comparatively low in the spherical particles having a high coercive rate 270, in the aggregation 290 of the spherical particles and in the contact 300 only at one point generated between the particles and the aggregated particles are easily dispersed. Since the particles have high resistance against fracture in the dispersion because of the spherical shape, the spherical particles can be extremely well dispersed. Thus, a medium with a low noise in which the magnetic characteristics are not deteriorated by fracture of the particles can be obtd.
WEST BRADFORD DRAKE
JAMES ROBERT OWEN
CHAMBERLAIN IV FREDERICK R
SMITH NEIL
WEXLER RONALD M
