Kao Corporation

Hirohide Mizunoya

Osamu Yoshida

Noriyuki Kitaori

Akira Shiga

Shigemi Wakabayashi

Katsumi Sasaki

Yuzo Matsuo

The present invention is a magnetic recording medium comprising a substrate and a magnetic layer including a binder resin and a plate-like magnetic powder of which easy axis of magnetization exists in a plane, and this magnetic recording medium is excellent in recording and regeneration characteristics.

Magnetic recording medium

A system for magnetic contact duplication by transferring an information signal recorded on a mother tape onto a blank tape, wherein the mother tape and the blank tape each includes at least one magnetic thin film having columns of magnetic grains grown obliquely, the column gradient .theta..sub.B1 of the magnetic grains in an uppermost magnetic thin film of the blank tape being smaller than the column gradient .theta..sub.M1 of the magnetic grains in an uppermost magnetic thin film of the mother tape, the mother tape and blank tape are superposed such that the column growth direction of the magnetic grains in the uppermost magnetic thin film of the mother tape and the column growth direction of the magnetic grains in the uppermost magnetic thin film of the blank tape intersect and such that these uppermost magnetic films face each other, and a bias magnetic field is applied from the substrate side of the blank tape.

System for magnetic contact duplication

A metal deposition magnetic recording medium comprising a support and at least one magnetic layer formed thereon by deposition, said recording medium having a residual magnetic flux density and a coercive force which satisfy the relationships of (1) and (2): ##EQU1## Br: Residual magnetic flux density H.sub.CV : Coercive force in the vertical direction

A metal film type magnetic recording medium in which the saturated magnetic flux density is high and iron having a good corrosion resistance is applied. The magnetic layer comprises metal films formed, in order on a base film, each containing iron, cobalt and nickel as main components.

Magnetic recording medium comprising successive magnetic metallic films

A magnetic recording medium is disclosed which comprises a support and formed thereover a magnetic layer having a multilayer structure comprising at least two vapor-deposited metal films each made up of columns, each vapor-deposited metal film having a degree of column curvature of 20% or lower, and any of said vapor-deposited metal films which is closer to said support having a higher degree of column curvature than any of said vapor-deposited metal films which is closer to the surface. The magnetic recording medium enables high-density recording, is excellent especially in output characteristics and C/N characteristics, and has a balance between longitudinal-direction magnetic characteristics and vertical-direction magnetic characteristics.

The present invention is directed to methods and apparatus for preparing a magnetic recording medium having a nonmagnetic substrate layer, a back-coat layer containing a metal or semi-metal which has been deposited in a vacuum on one surface of the substrate, a magnetic layer which has been deposited in a vacuum on the other surface of the substrate, and an optional top-coat layer which has been sprayed in a vacuum onto the magnetic layer. A quantity of oxygen is introduced during depositing of the back-coat layer to obtain a surface resistance of 5 to 10.sup.5 ohms.

Magnetic recording medium manufacturing method and manufacturing

A magnetic recording medium which is uncostly, can dispense with environmental pollution control measures unlike the case of Co or Cr, is highly durable, permits high density recording and comprises a magnetic film selected from the group consisting of:

Magnetic recording medium and process for producing the same

There is provided an apparatus for producing a magnetic recording medium which enables a good-quality magnetic recording medium to be produced with an improved production efficiency. This apparatus comprises a back-coat layer-coating vacuum chamber, a magnetic layer-coating vacuum chamber, a lubricant layer-coating vacuum chamber and a slitting vacuum chamber provided in a housing under vacuum, wherein the back-coat layer-coating vacuum chamber includes a melting pot disposed under a substrate and containing a metal, an electron beam-emitting device, and a guiding roller for reversing the surfaces of the substrate; the magnetic layer-coating vacuum chamber includes a melting pot disposed under the substrate and containing a magnetic substance, an electron beam-emitting device, and an oxidizing gas introduction means; the lubricant layer-coating vacuum chamber includes a lubricant-providing means disposed under the substrate; and the slitting vacuum chamber includes a winding means, a slitter, and an oxidizing gas-providing means.

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Tochigi, Japan

Hirohide Mizunoya