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Patent US4592952A successfully refreshed from Google Patents.
US4592952A
Expired / Lapsed
US
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Magnetic recording medium
Assignee: Fujifilm Holdings Corp
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Filing: 1983-09-26
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Granted: 1986-06-03
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Expires: 2003-09-26
Abstract
Abstract A magnetic recording medium comprising a non-magnetic support, a magnetic layer on a surface of the non-magnetic support, and a backing layer on a reverse surface of the non-magnetic support, composed of powder and a binder, and having a thickness of not more that 2 microns, wherein said powder comprises TiO 2 powder and carbon black powder in the weight ratio of 4:6 to 10:0. The average particle size of TiO 2 powder ranges from 0.01 to 0.8 microns.
Inventors
- 👤 Takahito Miyoshi
- 👤 Toshimitu Okutu
- 👤 Masaaki Fujiyama
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 07:03
CPC Classifications
G; G11; G11B; G11B5/00; G11B5/62; G11B5/73; G11B5/735; G11B5/7356; G11B5/7358; Y; Y10; Y10S; Y10S428/00; Y10S428/90; Y10T; Y10T428/00; Y10T428/25; Y10T428/256; Y10T428/257; Y10T428/26; Y10T428/261; Y10T428/266
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
81 words
A magnetic recording medium comprising a non-magnetic support, a magnetic layer on a surface of the non-magnetic support, and a backing layer on a reverse surface of the non-magnetic support, said backing layer being composed of a powder and a binder and having a thickness of not more than 2 microns, wherein said powder comprises TiO 2 powder having an average particle size ranging from 0.01 to 0.8 microns and carbon black powder in the weight ratio of 4:6 to 6:4.
Claim 2
Dependent Claim
81 words
A magnetic recording medium comprising a non-magnetic support, a magnetic layer on a surface of the non-magnetic support, and a backing layer on a reverse surface of the non-magnetic support, said backing layer being composed of a powder and a binder and having a thickness of not more than 2 microns, wherein said powder comprises TiO 2 powder having an average particle size ranging from 0.01 to 0.8 microns and carbon black powder in the weight ratio of 4:6 to 6:4.
Claim 3
Dependent Claim
26 words
A magnetic recording medium defined in claim 1 wherein the average particle size of carbon black powder is in the range of 15 to 200 millimicrons.
Claim 4
Dependent Claim
31 words
A magnetic recording medium defined in claim 1 wherein TiO 2 and carbon black powders are not less than 30 percent by weight of total powdery amount in the backing layer.
Claim 5
Dependent Claim
29 words
A magnetic recording medium defined in claim 1 wherein the weight ratio of powder to the binder in the backing layer is in the range of 2.5:1 to 0.1:1.
Claim 6
Dependent Claim
23 words
A magnetic recording medium defined in claim 1 wherein the binder in the backing layer comprises cellulosic resin, thermoplastic polyurethane elastomer and polyisocyanate.
Claim 7
Dependent Claim
36 words
A magnetic recording medium defined in claim 1 wherein the average surface roughness (Ra) of the backing layer, when measured at the center line of a cut-off of 0.08 mm, is not more than 0.05 microns.
Claim 8
Dependent Claim
23 words
A magnetic recording medium defined in claim 8 wherein the average surface (Ra) of the backing layer is not more than 0.024 microns.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1989-06-02 | 1989-12-02 | 1990-06-03 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1993-06-02 | 1993-12-02 | 1994-06-03 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1997-06-02 | 1997-12-02 | 1998-06-03 | $7700.00 | Window Closed / Lapsed |