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Patent US4687703A successfully refreshed from Google Patents.
US4687703A
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Magnetic recording medium
Assignee: Fujifilm Holdings Corp
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Filing: 1986-06-13
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Granted: 1987-08-18
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Expires: 2006-06-13
Abstract
Abstract A magnetic recording medium is described, comprising a non-magnetic support having coated thereon a magnetic layer, the magnetic layer containing (i) ferromagnetic alloy particles having a specific surface area (S BET ) of 48 m 2 /g or more and (ii) inorganic particles having an average particle size of 0.2 μm or less and having a Mohs' hardness of 6 or more in an amount of 10 to 30 wt % based on the total weight of ferromagnetic alloy particles.
Inventors
- 👤 Takahito Miyoshi
- 👤 Masaaki Fujiyama
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 01:42
CPC Classifications
G; G11; G11B; G11B5/00; G11B5/62; G11B5/68; G11B5/70; G11B5/714; G11B5/708; G11B5/7085; Y; Y10; Y10S; Y10S428/00; Y10S428/90; Y10T; Y10T428/00; Y10T428/25
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
77 words
A magnetic recording medium comprising a non-magnetic support having coated thereon a magnetic layer, wherein the magnetic layer contains (i) ferromagnetic alloy particles having a specific surface area (SBET) of 48 m 2 /g or more and (ii) inorganic particles having an average particle size of 0.2 μm or less and having a Mohs' hardness of 6 or more in an amount of 10 to 30 wt % based on the total weight of ferromagnetic alloy particles.
Claim 2
Dependent Claim
77 words
A magnetic recording medium comprising a non-magnetic support having coated thereon a magnetic layer, wherein the magnetic layer contains (i) ferromagnetic alloy particles having a specific surface area (SBET) of 48 m 2 /g or more and (ii) inorganic particles having an average particle size of 0.2 μm or less and having a Mohs' hardness of 6 or more in an amount of 10 to 30 wt % based on the total weight of ferromagnetic alloy particles.
Claim 3
Dependent Claim
27 words
A magnetic recording medium as claimed in claim 1, wherein the specific surface area (SBET) of the ferromagnetic alloy particles is 54 m 2 /g or more.
Claim 4
Dependent Claim
21 words
A magnetic recording medium as claimed in claim 1, wherein the inorganic particles have a Mohs' hardness of 8 or more.
Claim 5
Dependent Claim
37 words
A magnetic recording medium as claimed in claim 1, wherein the inorganic particles are contained in an amount of 10 to 20 wt % based on the total weight of ferromagnetic alloy particles in the magnetic layer.
Claim 6
Dependent Claim
35 words
A magnetic recording medium as claimed in claim 1, wherein the magnetic layer contains a binder in a total amount of 10 to 100 parts by weight per 100 parts of the ferromagnetic alloy particles.
Claim 7
Dependent Claim
17 words
A magnetic recording medium as claimed in claim 1, wherein the magnetic layer contains additionally carbon black.
References Cited (Backward Citations)
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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) | 1990-08-17 | 1991-02-16 | 1991-08-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1994-08-17 | 1995-02-16 | 1995-08-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1998-08-17 | 1999-02-16 | 1999-08-18 | $7700.00 | Window Closed / Lapsed |