US4780353A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Magnetic recording medium
Assignee: Fujifilm Holdings Corp
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Filing: 1987-08-06
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Granted: 1988-10-25
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Expires: 2007-08-06
Abstract
Abstract A magnetic recording medium comprising a flexible support having coated thereon a magnetic layer is disclosed. The support has a surface roughness of from 0.01 to 0.1 μm, the magnetic recording medium has a percent heat shrinkage of 1% or less in the direction of maximum shrinkage thereof after standing at 110° C. for 4 hours, and the magnetic layer contains a metal or alloy fine powder as a ferromagnetic powder. The magnetic recording medium has a excellent running property after repeated use and a small percent heat shrinkage.
Inventors
- 👤 Masatoshi Takahashi
- 👤 Chiaki Mizuno
- 👤 Hiroshi Ogawa
- 👤 Yasuo Tamai
- 👤 Noburo Hibino
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 00:06
CPC Classifications
G; G11; G11B; G11B5/00; G11B5/62; G11B5/68; G11B5/70; G11B5/706; G11B5/70605; G11B5/70615; G11B5/73; G11B5/739; G11B5/73923; G11B5/73927; Y; Y10; Y10S; Y10S428/00; Y10S428/90; Y10T; Y10T428/00; Y10T428/24; Y10T428/24355; Y10T428/25; Y10T428/256; Y10T428/31504; Y10T428/31786
Claims Analysis
Total Claims: 18
Claim 1
Independent Claim
130 words
A magnetic recording medium comprising a flexible support having coated thereon a magnetic layer comprising a non-curable binder, wherein said support has a center line average surface roughness at a cut-off value of 0.25 mm of from 0.01 to 0.1 μm on the side opposite to the magnetic layer, said magnetic recording medium has a percent heat shrinkage of 1% or less in the direction of maximum shrinkage thereof after standing at 110° C. for 4 hours, and said magnetic layer contains a metal or alloy fine powder having a metal content of 75% by weight or more, wherein not less than 50% by weight of said metal content is iron and having a S DET surface area of from 30 to 60 m 2 /g as a ferromagnetic powder.
Claim 2
Dependent Claim
130 words
A magnetic recording medium comprising a flexible support having coated thereon a magnetic layer comprising a non-curable binder, wherein said support has a center line average surface roughness at a cut-off value of 0.25 mm of from 0.01 to 0.1 μm on the side opposite to the magnetic layer, said magnetic recording medium has a percent heat shrinkage of 1% or less in the direction of maximum shrinkage thereof after standing at 110° C. for 4 hours, and said magnetic layer contains a metal or alloy fine powder having a metal content of 75% by weight or more, wherein not less than 50% by weight of said metal content is iron and having a S DET surface area of from 30 to 60 m 2 /g as a ferromagnetic powder.
Claim 3
Dependent Claim
29 words
A magnetic recorder medium as in claim 1, wherein said support has a surface roughness of from 0.02 to 0.08 μm on the side opposite to the magnetic layer.
Claim 4
Dependent Claim
29 words
A magnetic recording medium as in claim 2, wherein said support has a surface roughness of from 0.03 to 0.06 μm on the side opposite to the magnetic layer.
Claim 5
Dependent Claim
37 words
A magnetic recording medium as in claim 1, wherein said magnetic recording medium has a percent heat shrinkage of 0.8% or less in the direction of maximum shrinkage thereof after standing at 110° C. for 4 hours.
Claim 6
Dependent Claim
35 words
A magnetic recording medium as in claim 1, wherein said support has a percent heat shrinkage of 1.8% or less in the direction of maximum shrinkage thereof after standing at 110° C. for 4 hours.
Claim 7
Dependent Claim
35 words
A magnetic recording medium as in claim 5, wherein said support has a percent heat shrinkage of 1.5% or less in the direction of maximum shrinkage thereof after standing at 110° C. for 4 hours.
Claim 8
Dependent Claim
41 words
A magnetic recording medium as in claim 5, wherein said support is a polyester film having a Young's modulus of from 450 to 650 Kg/mm 2 in its lengthwise direction and from 450 to 550 Kg/mm 2 in its widthwise direction.
Claim 9
Dependent Claim
34 words
A magnetic recording medium as in claim 5, wherein said support is a polyester film having a reduced percent heat shrinkage which is obtained by heat treating a stretched polyester film at 110° C.
Claim 10
Dependent Claim
25 words
A magnetic recording medium as in claim 1, wherein said metal or alloy fine powder has a metal content of 80% by weight or more.
Claim 11
Dependent Claim
21 words
A magnetic recording medium as in claim 9, wherein not less than 50% by weight of said metal content is iron.
Claim 12
Dependent Claim
74 words
A magnetic recording medium as in claim 1, wherein said support has a surface roughness of from 0.02 to 0.08 μm on the side opposite to the magnetic layer, said magnetic recording medium has a percent heat shrinkage of 0.8% or less in the direction of maximum shrinkage thereof after standing at 110° C. for 4 hours, and said metal or alloy fine powder has a metal content of 75% by weight or more.
Claim 13
Dependent Claim
35 words
A magnetic recording medium as in claim 11, wherein said support has a percent heat shrinkage of 1.8% or less in the direction of maximum shrinkage thereof after standing at 110° C. for 4 hours.
Claim 14
Dependent Claim
21 words
A magnetic recording medium as in claim 11, wherein not less than 50% by weight of said metal content is iron.
Claim 15
Dependent Claim
29 words
A magnetic recording medium as in claim 11, wherein said support has a surface roughness of from 0.03 to 0.06 μm on the side opposite to the magnetic layer.
Claim 16
Dependent Claim
25 words
A magnetic recording medium as in claim 14, wherein said metal or alloy fine powder has a metal content of 80% by weight or more.
Claim 17
Dependent Claim
35 words
A magnetic recording medium as in claim 15, wherein said support has a percent heat shrinkage of 1.5% or less in the direction of maximum shrinkage thereof after standing at 110° C. for 4 hours.
Claim 18
Dependent Claim
21 words
A magnetic recording medium as in claim 15, wherein not less than 50% by weight of said metal content is iron.
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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) | 1991-10-25 | 1992-04-25 | 1992-10-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-10-25 | 1996-04-25 | 1996-10-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-10-25 | 2000-04-25 | 2000-10-25 | $7700.00 | Window Closed / Lapsed |