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Patent US5196265A successfully refreshed from Google Patents.
US5196265A
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US
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Magnetic recording medium
Assignee: Fujifilm Holdings Corp
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Filing: 1991-10-07
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Granted: 1993-03-23
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Expires: 2011-10-07
Abstract
Abstract A magnetic recording medium comprising a non-magnetic support having thereon a magnetic layer containing a ferromagnetic powder and a binder, the non-magnetic support comprising polyethylene naphthalate in which Young's modulus in the transversal direction is at least 700 kg/mm 2 and Young's modulus in the mechanical direction is less than 800 kg/mm 2 , the ferromagnetic powder being magnetic metal powder, and the total thickness of the magnetic recording material being not more than 11 μm.
Inventors
- 👤 Katsumi Ryoke
- 👤 Yutaka Kakuishi
- 👤 Toshiyuki Kitahara
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 00:16
CPC Classifications
G; G11; G11B; G11B5/00; G11B5/62; G11B5/73; G11B5/739; G11B5/73923; G11B5/73927; G11B5/73929; Y; Y10; Y10S; Y10S428/00; Y10S428/90; Y10T; Y10T428/00; Y10T428/12; Y10T428/12493; Y10T428/12771; Y10T428/12861; Y10T428/12931; Y10T428/12937; Y10T428/26; Y10T428/31504; Y10T428/31786
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
134 words
A magnetic recording medium for use in a digital recording system comprising a non-magnetic support having thereon a magnetic layer containing a ferromagnetic powder and a binder, said non-magnetic support comprising polyethylene naphthalate in which Young's Modulus in the transverse direction is at least 700 to 900 kg/mm 2 and Young's Modulus in the longitudinal direction is from 600 to less than 800 kg/mm 2 , the ferromagnetic powder being magnetic metal powder, and the total thickness of said magnetic recording medium being not more than 11 μm and wherein the coercive force (Hc) and maximum magnetic flux density (Bm) of said magnetic recording medium are at least 1400 Oe and at least 3,000 gauss, respectively, and wherein a short wave recording wavelength of said magnetic recording medium is not more than 0.8 μm.
Claim 2
Dependent Claim
134 words
A magnetic recording medium for use in a digital recording system comprising a non-magnetic support having thereon a magnetic layer containing a ferromagnetic powder and a binder, said non-magnetic support comprising polyethylene naphthalate in which Young's Modulus in the transverse direction is at least 700 to 900 kg/mm 2 and Young's Modulus in the longitudinal direction is from 600 to less than 800 kg/mm 2 , the ferromagnetic powder being magnetic metal powder, and the total thickness of said magnetic recording medium being not more than 11 μm and wherein the coercive force (Hc) and maximum magnetic flux density (Bm) of said magnetic recording medium are at least 1400 Oe and at least 3,000 gauss, respectively, and wherein a short wave recording wavelength of said magnetic recording medium is not more than 0.8 μm.
Claim 3
Dependent Claim
38 words
A magnetic recording medium as claimed in claim 1, wherein the thickness and central line average surface roughness (Ra) of said non-magnetic support are in a range of 5 to 9 μm and less than 12 nm, respectively.
Claim 4
Dependent Claim
17 words
A magnetic recording medium as claimed in claim 1, wherein said medium further comprises a backing layer.
Claim 5
Dependent Claim
27 words
A magnetic recording medium as claimed in claim 1, wherein a central line average surface roughness (Ra) of said magnetic layer is not more than 11 nm.
Claim 6
Dependent Claim
23 words
A magnetic recording medium as claimed in claim 1, wherein the squareness ratio (SQ) of said magnetic recording medium is 0.87 or more.
References Cited (Backward Citations)
US4614687A
Cited
US4720412A
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US4804736A
Cited
US4710421A
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US5055349A
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US5051292A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1996-03-22 | 1996-09-21 | 1997-03-23 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2000-03-22 | 2000-09-21 | 2001-03-23 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2004-03-22 | 2004-09-21 | 2005-03-23 | $7700.00 | Window Closed / Lapsed |