Patent US4071654A successfully refreshed from Google Patents.
US4071654A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Magnetic recording member
Assignee: Fujifilm Holdings Corp
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Filing: 1975-08-28
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Granted: 1978-01-31
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Expires: 1995-08-28
Abstract
Abstract A magnetic recording material comprising a non-magnetic flexible support having thereon a magnetic recording layer comprising a ferromagnetic powder dispersed in a binder, the surface of the non-magnetic flexible support having the magnetic recording layer thereon satisfying an S-factor expressed by the following relationship (I-1) ##EQU1## wherein S 1 is the surface roughness in μm of the surface of the non-magnetic flexible support having the magnetic recording layer thereon and d is the thickness in μm of the magnetic recording layer, with the thickness (d) of the magnetic recording layer being about 5 μm or less, and the back surface of the non-magnetic flexible support opposite that having the magnetic recording layer thereon satisfying an S-factor expressed by the following relationship (I-2) ##EQU2## wherein S 2 is the surface roughness in μm of the back surface of the non-magnetic support opposite that having the magnetic recording layer thereon and d is as described above.
Inventors
- 👤 Hiroshi Ogawa
- 👤 Kazuhide Ishii
- 👤 Matsuaki Nakamura
- 👤 Yasuo Tamai
- 👤 Goro Akashi
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 02:18
CPC Classifications
G; G11; G11B; G11B5/00; G11B5/62; G11B5/68; G11B5/70; Y; Y10; Y10S; Y10S428/00; Y10S428/90; Y10T; Y10T428/00; Y10T428/26; Y10T428/263; Y10T428/264; Y10T428/265; Y10T428/266; Y10T428/269; Y10T428/31
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
159 words
A magnetic recording material comprising a nonmagnetic flexible support up to 50 μm thick having thereon a magnetic recording layer comprising a ferromagnetic powder dispersed in a binder, the surface of said non-magnetic flexible support having the magnetic recording layer thereon satisfying an S-factor expressed by the following relationship (I-1) ##EQU15## wherein S 1 is the surface roughness in μm of the surface of the non-magnetic flexible support having the magnetic recording layer thereon and d is the thickness in μm of the magnetic recording layer, with the thickness (d) of the magnetic recording layer being about 3 μm or less, and the back surface of said non-magnetic flexible support opposite that having said magnetic recording layer thereon satisfying an S-factor expressed by the following relationship (I-2). ##EQU16## wherein S 2 is the surface roughness in μm of the back surface of the non-magnetic support opposite that having said magnetic recording layer thereon and d is as described above.
Claim 2
Dependent Claim
159 words
A magnetic recording material comprising a nonmagnetic flexible support up to 50 μm thick having thereon a magnetic recording layer comprising a ferromagnetic powder dispersed in a binder, the surface of said non-magnetic flexible support having the magnetic recording layer thereon satisfying an S-factor expressed by the following relationship (I-1) ##EQU15## wherein S 1 is the surface roughness in μm of the surface of the non-magnetic flexible support having the magnetic recording layer thereon and d is the thickness in μm of the magnetic recording layer, with the thickness (d) of the magnetic recording layer being about 3 μm or less, and the back surface of said non-magnetic flexible support opposite that having said magnetic recording layer thereon satisfying an S-factor expressed by the following relationship (I-2). ##EQU16## wherein S 2 is the surface roughness in μm of the back surface of the non-magnetic support opposite that having said magnetic recording layer thereon and d is as described above.
Claim 3
Dependent Claim
62 words
The magnetic recording material of claim 1, wherein the S-factor for the surface of said non-magnetic support having said magnetic recording layers thereon is expressed by the relationship (II-1), ##EQU17## and the S-factor for the back surface of said non-magnetic support is expressed by the relationship (II-2). ##EQU18## wherein S 1 , S 2 and d are as defined in claim 1.
Claim 4
Dependent Claim
50 words
The magnetic recording material of claim 1, wherein said ferromagnetic powder is at least one member selected from the group consisting of a ferromagnetic alloy powder, a chromium dioxide powder, a Co-containing Fe 3 O 4 powder, a Co-containing Berthollide iron oxide, and a Co-containing γ-Fe 2 O 3 .
Claim 5
Dependent Claim
16 words
The magnetic recording material of claim 1, wherein said ferromagnetic powder is a ferromagnetic alloy powder.
Claim 6
Dependent Claim
11 words
A video tape comprising the magnetic recording material of claim 1.
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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) | 1981-01-30 | 1981-08-01 | 1982-01-31 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1985-01-30 | 1985-08-01 | 1986-01-31 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1989-01-30 | 1989-08-01 | 1990-01-31 | $7700.00 | Window Closed / Lapsed |