US4034410A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Magnetic recording medium
Assignee: Kanegafuchi Chemical Industry Co Ltd
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Filing: 1975-04-10
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Granted: 1977-07-05
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Expires: 1995-04-10
Abstract
Abstract A magnetic recording medium comprising a magnetic sheet of domain sized particles of at least one member selected from the group consisting of barium ferrite, strontium ferrite and lead ferrite, dispersed uniformly in an organic binder, and a ferromagnetic plate bonded to one surface with the other surface of the sheet being magnetizable at selected sites with the magnetization being in a direction substantially perpendicular to the surfaces.
Inventors
- 👤 Kazuo Suzuki
- 👤 Shinichiro Akuta
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 09:05
CPC Classifications
G; G11; G11B; G11B5/00; G11B5/62; G11B5/68; G11B5/70; G11B5/706; G11B5/70626; G11B5/70642; G11B5/70678
Claims Analysis
Total Claims: 3
Claim 1
Independent Claim
156 words
A magnetic recording system comprising a magnetic sheet of domain sized particles of at least one member selected from the group consisting of barium ferrite, strontium ferrite and lead ferrite, uniformily dispersed in an organic binder, and a ferromagnetic plate bonded to one surface of said sheet, the other surface of said sheet being magnetizable at selected locations, means comprising an electromagnet having a substantially rod shaped core for magnetizing said particles at said selected locations in said other surface in a direction substantially perpendicular to said other surface, thereby to store information in the orientation of magnetic flux in perpendicular magnetic particles, means for detecting only one type of magnetic pole at said selected locations, and means comprising an electromagnet having a substantially rod shaped core for erasing the information stored in said perpendicularly oriented magnetic particles at all locations by changing the type of magnetic pole to be non-detectable by said means for detecting.
Claim 2
Dependent Claim
156 words
A magnetic recording system comprising a magnetic sheet of domain sized particles of at least one member selected from the group consisting of barium ferrite, strontium ferrite and lead ferrite, uniformily dispersed in an organic binder, and a ferromagnetic plate bonded to one surface of said sheet, the other surface of said sheet being magnetizable at selected locations, means comprising an electromagnet having a substantially rod shaped core for magnetizing said particles at said selected locations in said other surface in a direction substantially perpendicular to said other surface, thereby to store information in the orientation of magnetic flux in perpendicular magnetic particles, means for detecting only one type of magnetic pole at said selected locations, and means comprising an electromagnet having a substantially rod shaped core for erasing the information stored in said perpendicularly oriented magnetic particles at all locations by changing the type of magnetic pole to be non-detectable by said means for detecting.
Claim 3
Dependent Claim
18 words
The system of claim 1, wherein said means for detecting comprises a magnetic proximity switch or hole switch.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1980-07-04 | 1981-01-03 | 1981-07-05 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1984-07-04 | 1985-01-03 | 1985-07-05 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1988-07-04 | 1989-01-03 | 1989-07-05 | $7700.00 | Window Closed / Lapsed |