US4572867A
Expired / Lapsed
US
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Magnetic recording medium
Assignee: Konica Minolta Inc
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Filing: 1983-10-26
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Granted: 1986-02-25
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Expires: 2003-10-26
Abstract
Abstract A magnetic recording medium comprising a support and a magnetic layer on said support. The magnetic layer is a unitary magnetic layer comprising ferromagnetic metallic powder. The average grain size of said ferromagnetic powder is not more than 0.5μ, the ratio of the major axis to the minor axis (acicular ratio) of said powders is from 1.3 to 4.5, and the coercive force of said powder is from 1350 Oe to 1600 Oe.
Inventors
- 👤 Issei Nakamura
- 👤 Kenji Itozawa
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 15:52
CPC Classifications
G; G11; G11B; G11B5/00; G11B5/62; G11B5/68; G11B5/70; G11B5/714; Y; Y10; Y10T; Y10T428/00; Y10T428/25; Y10T428/256
Claims Analysis
Total Claims: 21
Claim 1
Independent Claim
75 words
A magnetic recording medium comprising a support and a magnetic layer on said support, said magnetic layer being a unitary magnetic layer comprising ferromagnetic metallic powder, the average grain size of said ferromagnetic powder being not more than 0.5μ, the ratio of the major axis to the minor axis (acicular ratio) of said ferromagnetic powder being from 1.3 to 4.5, and the coercive force of said ferromagnetic powder being from 1350 Oe to 1600 Oe.
Claim 2
Dependent Claim
75 words
A magnetic recording medium comprising a support and a magnetic layer on said support, said magnetic layer being a unitary magnetic layer comprising ferromagnetic metallic powder, the average grain size of said ferromagnetic powder being not more than 0.5μ, the ratio of the major axis to the minor axis (acicular ratio) of said ferromagnetic powder being from 1.3 to 4.5, and the coercive force of said ferromagnetic powder being from 1350 Oe to 1600 Oe.
Claim 3
Dependent Claim
26 words
The magnetic recording medium according to claim 1, wherein said ferromagnetic metallic powder is selected from the group consisting of Fe-, Ni-, Co- and Cr-containing powder.
Claim 4
Dependent Claim
17 words
The magnetic recording medium according to claim 1, wherein said ferromagnetic powder is an iron-containing metallic powder.
Claim 5
Dependent Claim
30 words
The magnetic recording medium according to claim 3, wherein said iron-containing metallic powder is selected from the group consisting of Fe--Co--Ni, Fe--Ni--Zn, Fe--Al, Fe--Al--P, Fe--Co--Ni--Cr, Fe--Co--Ni--P, Fe--Ni, Fe--Ni--Mn, Fe--Ni--Cr--P, Fe--Ni--Co--Zn.
Claim 6
Dependent Claim
25 words
The magnetic recording medium according to claim 3, wherein said iron-containing metallic powder contains iron in an amount of not less than 60% by weight.
Claim 7
Dependent Claim
29 words
The magnetic recording medium according to claim 2, wherein said ferromagnetic powder is an iron-containing metallic powder containing iron in an amount of not less than 80% by weight.
Claim 8
Dependent Claim
17 words
The magnetic recording medium according to claim 1, wherein said ferromagnetic magnetic layer also contains a binder.
Claim 9
Dependent Claim
38 words
The magnetic recording medium according to claim 7, wherein said binder is contained in said magnetic layer at a proportion of 5 to 400 parts by weight relative to 100 parts by weight of of said ferromagnetic powder.
Claim 10
Dependent Claim
36 words
The magnetic recording medium according to claim 7, wherein said binder is contained in said magnetic layer at an amount of 10 to 100 parts by weight per 100 parts by weight of said ferromagnetic powder.
Claim 11
Dependent Claim
32 words
The magnetic recording medium according to claim 7, wherein said binder is selected from the group consisting of thermoplastic resins, thermosetting resins, radiation curable resins, reactive resins, electron-irradiation-setting resins and mixture thereof.
Claim 12
Dependent Claim
24 words
The magnetic recording medium according to claim 1, wherein said support is selected from the group consisting of polymeric resins, non-magnetic metals and ceramics.
Claim 13
Dependent Claim
30 words
The magnetic recording medium according to claim 11, wherein said support is a polymeric resin selected from the group consisting of polyesters, polyolefins, cellulose derivatives, polycarbonate, polyvinylchloride, polyimide and nylon.
Claim 14
Dependent Claim
23 words
The magnetic recording medium according to claim 11, wherein said support is a non-magnetic metal support of aluminum, zinc or an alloy thereof.
Claim 15
Dependent Claim
24 words
The magnetic recording medium according to claim 11, wherein said support is in the form of film or sheet, card, disc or cylindrical drum.
Claim 16
Dependent Claim
24 words
The magnetic recording medium according to claim 1, wherein said average grain size of said ferromagnetic powder is between 0.05 micron to 0.5 micron.
Claim 17
Dependent Claim
24 words
The magnetic recording medium according to claim 15, wherein said average grain size of said ferromagnetic powder is between 0.1 micron to 0.3 micron.
Claim 18
Dependent Claim
53 words
The magnetic recording medium according to claim 6, wherein said ferromagnetic layer also contains a binder in an amount of between 10 and 100 parts by weight per 100 parts by weight of said ferromagnetic powder and wherein said average grain size of said ferromagnetic powder is between 0.05 micron and 0.5 micron.
Claim 19
Dependent Claim
55 words
The magnetic recording medium according to claim 17, wherein said binder is selected from the group consisting of thermoplastic resins, thermosetting resins, radiation curable resins, reactive resins, electron-irradiation-setting resins and mixtures thereof and wherein said support is a polymeric resin selected from the group consisting of polyesters, polyolefins, cellulose derivatives, polycarbonate, polyvinylchloride, polyimide and nylon.
Claim 20
Dependent Claim
24 words
The magnetic recording medium according to claim 18, wherein said average grain size of said ferromagnetic powder is between 0.1 micron to 0.3 micron.
Claim 21
Dependent Claim
40 words
The magnetic recording medium according to claim 18, wherein said support is a non-magnetic metal support of aluminum, zinc or an alloy thereof and wherein said average grain size of said ferromagnetic powder is between 0.1 micron to 0.3 micron.
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) | 1989-02-24 | 1989-08-26 | 1990-02-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1993-02-24 | 1993-08-26 | 1994-02-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1997-02-24 | 1997-08-26 | 1998-02-25 | $7700.00 | Window Closed / Lapsed |