US4425401A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Magnetic recording media
Assignee: Toshiba Corp
•
Filing: 1982-06-30
•
Granted: 1984-01-10
•
Expires: 2002-06-30
Abstract
Abstract Disclosed is a magnetic recording medium comprising substrate and a resinous composition containing magnetic particles of uniaxially-anisotropic hexagonal crystals having particle diameters of 0.01˜0.3 μm and coated on said substrate; the ratio of remanent magnetization to saturation magnetization on the magnetization curve corrected to demagnetizing field which is measured in a direction vertical to the surface of the recording medium, ranging from 0.3 to 0.7. This magnetic recording medium requires no orientation treatment for its production.
Inventors
- 👤 Tadashi Ido
- 👤 Hirotaka Yokoyama
- 👤 Moriyasu Wada
- 👤 Toshihiko Oguchi
- 👤 Akio Ishizawa
- 👤 Yoshiyasu Koike
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 20:14
CPC Classifications
G; G11; G11B; G11B5/00; G11B5/62; G11B5/68; G11B5/70; G11B5/706; G11B5/70626; G11B5/70642; G11B5/70678; G11B5/714; G11B5/84; G11B5/842; G11B5/845; Y; Y10; Y10S; Y10S428/00; Y10S428/90; Y10T; Y10T428/00; Y10T428/25; Y10T428/256; Y10T428/257; Y10T428/258
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
72 words
A magnetic recording medium comprising a substrate and a resinous composition containing magnetic particles of uniaxially-anisotropic hexagonal crystals having particle diameters of from 0.01 to 0.3 μm and coated on said substrate; the ratio of remanent magnetization to saturation magnetization on the magnetization curve for the recording medium, corrected to a demagnetizing field which is measured in a direction vertical to the surface of the recording medium, ranging from 0.3 to 0.7.
Claim 2
Dependent Claim
72 words
A magnetic recording medium comprising a substrate and a resinous composition containing magnetic particles of uniaxially-anisotropic hexagonal crystals having particle diameters of from 0.01 to 0.3 μm and coated on said substrate; the ratio of remanent magnetization to saturation magnetization on the magnetization curve for the recording medium, corrected to a demagnetizing field which is measured in a direction vertical to the surface of the recording medium, ranging from 0.3 to 0.7.
Claim 3
Dependent Claim
19 words
The magnetic recording medium according to claim 1, wherein the magnetic particles comprise a substituted or unsubstituted hexagonal ferrite.
Claim 4
Dependent Claim
28 words
The magnetic recording medium according to claim 2, wherein said hexagonal ferrite is selected from the group consisting of Ba ferrite, Sr ferrite, Pb ferrite and Ca ferrite.
Claim 5
Dependent Claim
43 words
The magnetic recording medium according to claim 2, wherein said hexagonal ferrite is selected from the group consisting of Ba ferrite, Sr ferrite, Pb ferrite and Ca ferrite whose Fe part is substituted in part with Co, Ti, Zn, Nb, Ta or Sb.
Claim 6
Dependent Claim
41 words
The magnetic recording medium according to claim 1, produced by a process which comprises coating said magnetic particle-containing resinous composition on said substrate and drying the coated substrate, without subjecting the recording medium to an orientation step in a magnetic field.
References Cited (Backward Citations)
US4075672A
Cited
US4207092A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1987-01-09 | 1987-07-11 | 1988-01-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1991-01-09 | 1991-07-11 | 1992-01-10 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1995-01-09 | 1995-07-11 | 1996-01-10 | $7700.00 | Window Closed / Lapsed |