Patent US4781964A successfully refreshed from Google Patents.
US4781964A
Expired / Lapsed
US
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Magnetic recording medium
Assignee: FUJI PHTO FILM Co Ltd A CORP OF JAPAN
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Filing: 1986-08-20
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Granted: 1988-11-01
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Expires: 2006-08-20
Abstract
Abstract A magnetic recording medium such as an audio-tape or a video-tape comprising a flexible support and a magnetic recording layer provided on a surface of said support, which is characterized in that the ratio of Young's modulus of said magnetic recording layer in the longitudinal direction (Em) to Young's modulus of said support in the longitudinal direction (Eb), namely Em/Eb, is in the range of 1.20-3.20.
Inventors
- 👤 Chiaki Mizuno
- 👤 Yasuo Tamai
- 👤 Hiroshi Ogawa
- 👤 Shinji Saito
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 11:59
CPC Classifications
G; G11; G11B; G11B5/00; G11B5/62; G11B5/73; G11B5/739; G11B5/73923; G11B5/73927; Y; Y10; Y10S; Y10S428/00; Y10S428/90; Y10T; Y10T428/00; Y10T428/24; Y10T428/24355
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
138 words
A magnetic recording medium comprising a flexible support and a magnetic recording layer provided on a surface of said support, wherein Young's modulus of said magnetic recording layer in its longitudinal direction is in the range of 720-2,000 kg/mm 2 , a Young's modulus of said support in its longitudinal direction is in the range of 450-650 kg/mm 2 , a ratio of Young's modulus of said magnetic recording layer in the longitudinal direction to Young's modulus of said support in the longitudinal direction is in the range of 1.20-3.20, a heat shrinkage ratio of said magnetic recording medium in its longitudinal direction after being allowed to stand at 110° C. for four hours is not higher than 0.008, and said support has a center line average height in the range of 0.02-0.1 μm on its back surface.
Claim 2
Dependent Claim
138 words
A magnetic recording medium comprising a flexible support and a magnetic recording layer provided on a surface of said support, wherein Young's modulus of said magnetic recording layer in its longitudinal direction is in the range of 720-2,000 kg/mm 2 , a Young's modulus of said support in its longitudinal direction is in the range of 450-650 kg/mm 2 , a ratio of Young's modulus of said magnetic recording layer in the longitudinal direction to Young's modulus of said support in the longitudinal direction is in the range of 1.20-3.20, a heat shrinkage ratio of said magnetic recording medium in its longitudinal direction after being allowed to stand at 110° C. for four hours is not higher than 0.008, and said support has a center line average height in the range of 0.02-0.1 μm on its back surface.
Claim 3
Dependent Claim
40 words
The magnetic recording medium as claimed in claim 1, wherein the ratio of Young's modulus of said magnetic recording layer in the longitudinal direction to Young's modulus of said support in the longitudinal direction is in the range of 1.25-2.50.
Claim 4
Dependent Claim
31 words
The magnetic recording medium as claimed in claim 1, wherein the Young's modulus of said magnetic recording layer in the longitudinal direction is in the range of 750-1,500 kg/mm 2 .
Claim 5
Dependent Claim
41 words
The magnetic recording medium as claimed in claim 1, wherein the heat shrinkage ratio of said magnetic recording medium in the longitudinal direction is not higher than 0.5% after said medium is allowed to stand at 110° C. for 4 hours.
Claim 6
Dependent Claim
28 words
The magnetic recording medium as claimed in claim 1, wherein said support has a center line average height in the range of 0.02-0.08 μm on the back surface.
Claim 7
Dependent Claim
28 words
The magnetic recording medium as claim in claim 1, wherein said support has a center line average height in the range of 0.03-0.06 μm on the back surface.
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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) | 1991-11-01 | 1992-05-02 | 1992-11-01 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-11-01 | 1996-05-02 | 1996-11-01 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-11-01 | 2000-05-02 | 2000-11-01 | $7700.00 | Window Closed / Lapsed |