Patent US4528240A successfully refreshed from Google Patents.
US4528240A
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Magnetic recording medium
Assignee: Fujifilm Holdings Corp
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Filing: 1984-02-02
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Granted: 1985-07-09
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Expires: 2004-02-02
Abstract
Abstract A magnetic recording medium includes a substrate, a magnetic layer and a subbing layer therebetween. The subbing layer includes tin oxide type powders having a mean particle size not higher than 0.8 micron. S/N ratio is improved.
Inventors
- 👤 Takahito Miyoshi
- 👤 Masaaki Fujiyama
- 👤 Toshimitu Okutu
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 12:58
CPC Classifications
G; G11; G11B; G11B5/00; G11B5/62; G11B5/73; G11B5/733; G11B5/7334; Y; Y10; Y10S; Y10S428/00; Y10S428/90; Y10T; Y10T428/00; Y10T428/25; Y10T428/251; Y10T428/252; Y10T428/256; Y10T428/257; Y10T428/259; Y10T428/26; Y10T428/261; Y10T428/29; Y10T428/2982; Y10T428/2991; Y10T428/2993; Y10T428/2995; Y10T428/2998
Claims Analysis
Total Claims: 18
Claim 1
Independent Claim
66 words
A magnetic recording medium including a substrate, a magnetic layer, and a subbing layer therebetween wherein said subbing layer has a thickness of 0.03 to 0.08 micron, and includes tin oxide type powders having a mean particle size of not higher than 0.08 micron and an organic binder in a ratio, by volume of the tin oxide type powder to the binder, of 1:99 to 70:30.
Claim 2
Dependent Claim
66 words
A magnetic recording medium including a substrate, a magnetic layer, and a subbing layer therebetween wherein said subbing layer has a thickness of 0.03 to 0.08 micron, and includes tin oxide type powders having a mean particle size of not higher than 0.08 micron and an organic binder in a ratio, by volume of the tin oxide type powder to the binder, of 1:99 to 70:30.
Claim 3
Dependent Claim
58 words
A magnetic recording medium as defined in claim 1 in which the tin oxide type powders include powders selected from the group consisting of powders of tin oxide, tin oxide-coated powders of a material other than tin oxide, colloidally dispersed tin oxide powders, and powders of tin oxide doped with SbO 2 or Sb 2 O 3 .
Claim 4
Dependent Claim
59 words
A magnetic recording medium as defined in claim 2, in which said material other than tin oxide of the oxide-coated powders are one or more selected from the group consisting of carbon black, graphite, tungsten disulfide, molybdenum disulfide, boron nitride, silicon dioxide, calcium carbonate, aluminum oxide, iron oxide, titanium dioxide, magnesium oxide, zinc oxide, calcium oxide, lithopone and talc.
Claim 5
Dependent Claim
24 words
A magnetic recording medium as defined in claim 2, in which said colloidally dispersed tin oxide powders are dispersed together with BaSO 4 .
Claim 6
Dependent Claim
28 words
A magnetic recording medium as defined in claim 1 in which said subbing layer further includes powders of inorganic pigment material other than the tin oxide type powders.
Claim 7
Dependent Claim
38 words
A magnetic recording medium as defined in claim 5 in which the amount of the tin oxide type powders is no less than 20 wt % of the total inorganic material powders including the other inorganic pigment powders.
Claim 8
Dependent Claim
38 words
A magnetic recording medium as defined in claim 6 in which the amount of the tin oxide type powders is no less than 40 wt % of the total inorganic material powders including the other inorganic pigment powders.
Claim 9
Dependent Claim
31 words
A magnetic recording medium as defined in claim 5 in which the mean particle size of the inorganic material powders including the tin oxide type powders is 0.01 to 0.8 micron.
Claim 10
Dependent Claim
31 words
A magnetic recording medium as defined in claim 8 in which the mean particle size of the inorganic material powders including the tin oxide type powders is 0.02 to 0.4 micron.
Claim 11
Dependent Claim
53 words
A magnetic recording medium as defined in claim 5 in which said inorganic pigment material is one or more selected from the group consisting of carbon black, graphite, tungsten disulfide, molybdenum disulfide, boron nitride, silicon dioxide, calcium carbonate, aluminum oxide, iron oxide, titanium oxide, magnesium oxide, zinc oxide, calcium oxide. lithopone and talc.
Claim 12
Dependent Claim
28 words
A magnetic recording medium as defined in claim 1 in which the ratio by volume of the total inorganic material powders to the binder is 1:99 to 60:40.
Claim 13
Dependent Claim
28 words
A magnetic recording medium as defined in claim 11 in which the ratio by volume of the total inorganic material powders to the binder is 5:95 to 50:50.
Claim 14
Dependent Claim
27 words
A magnetic recording medium as defined in claim 12 in which the ratio by volume of the inorganic material powders to the binder is 10:90 to 40:60.
Claim 15
Dependent Claim
33 words
A magnetic recording medium as defined in claim 1 in which the ratio by volume of the tin oxide type powder in the inorganic material powder to the binder is 10:90 to 30:70.
Claim 16
Dependent Claim
21 words
A magnetic recording medium as defined in claim 1 in which the organic binder includes thermoplastic resin or a mixture thereof.
Claim 17
Dependent Claim
22 words
A magnetic recording medium as defined in claim 1 in which the subbing layer has a thickness of 0.05 to 0.2 micron.
Claim 18
Dependent Claim
35 words
A magnetic recording medium as defined in claim 5 in which the subbing layer includes a binder and the ratio by volume of the total inorganic material powders to the binder is 1:99 to 60:40.
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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) | 1988-07-08 | 1989-01-07 | 1989-07-09 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1992-07-08 | 1993-01-07 | 1993-07-09 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1996-07-08 | 1997-01-07 | 1997-07-09 | $7700.00 | Window Closed / Lapsed |