US4663209A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Magnetic recording medium
Assignee: Fujifilm Holdings Corp
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Filing: 1985-04-17
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Granted: 1987-05-05
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Expires: 2005-04-17
Abstract
Abstract Magnetic recording medium is disclosed which comprises a non-magnetic support having coated thereon a magnetic layer mainly containing ferromagnetic metal particles and a binder: (1) wherein the non-magnetic support is a polyester film having a thickness of 4 to 12 μm, (b) an F5 value in a machine direction of 16 kg/mm 2 or more, (c) a breaking strength in a machine direction of 25 kg/mm 2 or more, (d) a breaking elongation in a machine direction of 90% or less, (e) a surface roughness (Ra) of 0.01 to 0.03 μm, and (f) a fish eye (FE), which is shown in terms of height (H), of 6H or more having 0 per 100 cm 2 , a fish eye of 5H having 2 or less per 100 cm 2 and a fish eye of 4H having 5 or less per 100 cm 2 ; (2) wherein the ferromagnetic metal particles have (a) a saturation magnetization (σs) of 110 to 160 emu/g, and (b) a specific surface area measured by the BET method of 25 to 65 m 2 /g; and (3) wherein the magnetic layer has (a) a coercive force (Hc) of 700 Oe or more, (b) a surface roughness (Ra) of 0.015 μm or less and (c) a thickness of 1.5 to 4.5 μm.
Inventors
- 👤 Masashi Aonuma
- 👤 Masaaki Suzuki
- 👤 Satoshi Sakakibara
- 👤 Noburo Hibino
- 👤 Koh Kamada
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 03:11
CPC Classifications
G; G11; G11B; G11B5/00; G11B5/62; G11B5/68; G11B5/70; G11B5/714; G11B5/73; G11B5/739; G11B5/73923; G11B5/73927; Y; Y10; Y10S; Y10S428/00; Y10S428/90; Y10T; Y10T428/00; Y10T428/24; Y10T428/24355; Y10T428/31504; Y10T428/31786
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
203 words
Magnetic recording medium comprising a non-magnetic support having coated thereon a magnetic layer mainly containing ferromagnetic metal particles and a binder: (1) wherein the non-magnetic support is a polyester film having (a) thickness of 4 to 12 μm, (b) an F5 value in a machine direction of 16 kg/mm 2 or more, (c) a breaking strength in a machine direction of 25 kg/mm 2 or more, (d) a breaking elongation in a machine direction of 90% or less, (e) a surface roughness (Ra) of 0.01 to 0.03 μm, and (f) fish eyes (FE), defined in terms of height (H), wherein there are no fish eyes of 6H, 2 or less fish eyes of 5H per 100 cm 2 , and less than 5 fish eyes of 4H per 100 cm 2 ; (2) wherein the ferromagnetic metal particles have (a) a saturation magnetization (σs) of 110 to 160 emu/g, and (b) a specific surface area measured by the BET method of 25 to 65 m 2 /g; and (3) wherein the magnetic layer has (a) a coercive force (Hc) of 700 Oe or more, (b) a surface roughness (Ra) of 0.015 m or less and (c) a thickness of 1.5 to 4.5 μm.
Claim 2
Dependent Claim
203 words
Magnetic recording medium comprising a non-magnetic support having coated thereon a magnetic layer mainly containing ferromagnetic metal particles and a binder: (1) wherein the non-magnetic support is a polyester film having (a) thickness of 4 to 12 μm, (b) an F5 value in a machine direction of 16 kg/mm 2 or more, (c) a breaking strength in a machine direction of 25 kg/mm 2 or more, (d) a breaking elongation in a machine direction of 90% or less, (e) a surface roughness (Ra) of 0.01 to 0.03 μm, and (f) fish eyes (FE), defined in terms of height (H), wherein there are no fish eyes of 6H, 2 or less fish eyes of 5H per 100 cm 2 , and less than 5 fish eyes of 4H per 100 cm 2 ; (2) wherein the ferromagnetic metal particles have (a) a saturation magnetization (σs) of 110 to 160 emu/g, and (b) a specific surface area measured by the BET method of 25 to 65 m 2 /g; and (3) wherein the magnetic layer has (a) a coercive force (Hc) of 700 Oe or more, (b) a surface roughness (Ra) of 0.015 m or less and (c) a thickness of 1.5 to 4.5 μm.
Claim 3
Dependent Claim
19 words
The magnetic recording medium of claim 1, wherein the non-magnetic support has a thickness of 4 to 10 μm.
Claim 4
Dependent Claim
26 words
The magnetic recording medium of claim 1, wherein the non-magnetic support has an F5 value in a machine direction of 16 to 24 kg/mm 2 .
Claim 5
Dependent Claim
26 words
The magnetic recording medium of claim 1, wherein the non-magnetic support has a breaking strength in a machine direction of 25 to 50 kg/mm 2 .
Claim 6
Dependent Claim
23 words
The magnetic recording medium of claim 1, wherein the non-magnetic support has a breaking elongation in a machine direction of 50 to 90%.
Claim 7
Dependent Claim
21 words
The magnetic recording medium of claim 1, wherein the non-magnetic support has a surface roughness (Ra) of 0.015 to 0.25 μm.
Claim 8
Dependent Claim
21 words
The magnetic recording medium of claim 1, wherein the ferromagnetic metal particles have a saturation magnetization of 115 to 145 emu/g.
Claim 9
Dependent Claim
29 words
The magnetic recording medium of claim 1, wherein said ferromagnetic metal particlas have a specific surface area measured by the BET method of 35 to 55 m 2 /g.
Claim 10
Dependent Claim
20 words
The magnetic recording medium of claim 1, wherein the magnetic layer has a coercive force of 1100 to 1650 Oe.
Claim 11
Dependent Claim
19 words
The magnetic recording medium of claim 1, wherein said magnetic layer has a thickness of 2.0 to 3.5 μm.
Claim 12
Dependent Claim
21 words
The magnetic recording medium of claim 1, wherein said magnetic layer has a surface roughness (Ra) of 0.013 to 0.006 μm.
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) | 1990-05-04 | 1990-11-03 | 1991-05-05 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1994-05-04 | 1994-11-03 | 1995-05-05 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1998-05-04 | 1998-11-03 | 1999-05-05 | $7700.00 | Window Closed / Lapsed |