Patent US3274436A successfully refreshed from Google Patents.
US4337288A
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Magnetic recording medium
Assignee: Fujifilm Holdings Corp
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Filing: 1980-11-17
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Granted: 1982-06-29
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Expires: 2000-11-17
Abstract
Abstract A magnetic recording medium comprising a coated magnetic recording layer having video and chroma S/N ratios appropriately balanced with tape transporting characteristics is attained by controlling the magnetic layer to have a surface roughness such that the maximum value of the arithmetical average roughness (Ra) is about 80 A or greater in the surface roughness pitch region greater than about 300 mu m while in the surface roughness pitch region of about 5 mu m to about 100 mu m the maximum value of the arithmetical average roughness (Ra) is about 40 A or less.
Inventors
- 👤 Haruo Takenaka
- 👤 Eiichi Tadokoro
- 👤 Masaaki Fujiyama
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 08:32
CPC Classifications
G; G11; G11B; G11B5/00; G11B5/62; G11B5/68; G11B5/70; G11B5/708; G11B5/7085; Y; Y10; Y10S; Y10S428/00; Y10S428/90; Y10T; Y10T428/00; Y10T428/24; Y10T428/24479; Y10T428/24612; Y10T428/25; Y10T428/256; Y10T428/257; Y10T428/258; Y10T428/31
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
178 words
A magnetic recording medium comprising a non-magnetic support on which a magnetic layer is formed by: coating on said support an emulsion of magnetic material in a binder, wherein said magnetic material is comprised of large filler having a grain size ranging from about 2 μm to about 30 μm and a small filler having a grain size ranging from about 0.01 μm to about 5 μm; and drying, and subjecting the resulting magnetic recording medium to a calendering process utilizing calender rolls under conditions that the pressure between any two rolls ranges from 100 Kg/cm to 400 Kg/cm at a temperature ranging from 20° C. to 150° C., said resulting magnetic layer having a surface roughness controlled such that the maximum value of the arithmetical average roughness is at least about 80 A in the surface roughness pitch region greater than about 300 μm and the maximum value of the arithmetical average roughness is about 40 A to 5 A in the surface roughness pitch region greater than about 5 μm and smaller than about 100 μm.
Claim 2
Dependent Claim
178 words
A magnetic recording medium comprising a non-magnetic support on which a magnetic layer is formed by: coating on said support an emulsion of magnetic material in a binder, wherein said magnetic material is comprised of large filler having a grain size ranging from about 2 μm to about 30 μm and a small filler having a grain size ranging from about 0.01 μm to about 5 μm; and drying, and subjecting the resulting magnetic recording medium to a calendering process utilizing calender rolls under conditions that the pressure between any two rolls ranges from 100 Kg/cm to 400 Kg/cm at a temperature ranging from 20° C. to 150° C., said resulting magnetic layer having a surface roughness controlled such that the maximum value of the arithmetical average roughness is at least about 80 A in the surface roughness pitch region greater than about 300 μm and the maximum value of the arithmetical average roughness is about 40 A to 5 A in the surface roughness pitch region greater than about 5 μm and smaller than about 100 μm.
Claim 3
Dependent Claim
66 words
A magnetic recording medium as in claim 1, wherein the maximum value of the arithmetical average roughness is from 120 A to 1,000 A in the surface roughness pitch region greater than about 300 μm, and the maximum value of the arithmetical average roughness is 20 A or less in the surface roughness pitch region greater than about 5 μm and smaller than about 100 μm.
Claim 4
Dependent Claim
39 words
A magnetic recording medium, as claimed in claim 1, wherein said large filler has a grain size of from 10 μm to 20 μm, and said small filler has a grain size ranging from 0.01 μm to 2 μm.
Claim 5
Dependent Claim
190 words
A process for producing a magnetic recording medium comprising the steps of: providing a non-magnetic support base having a surface; coating said non-magnetic support base surface with an emulsion of magnetic material comprising a large filler having a grain size ranging from about 2 μm to about 30 μm and a small filler having a grain size ranging from about 0.01 μm to about 5 μm; drying said emulsion of magnetic material to form a magnetic layer on said non-magnetic support surface; and subjecting the resulting magnetic recording medium to calendering utilizing calender rolls under conditions such that the pressure between two rolls ranges from 100 Kg/cm to 400 Kg/cm at a temperature ranging from 20° C. to 150° C. resulting in a magnetic layer having a surface roughness controlled such that the maximum value of the arithmetical average roughness is at least about 80 A in the surface roughness pitch region greater than about 300 μm and the maximum value of the arithmetical average roughness is about 40 A to 5 A in the surface roughness pitch region greater than about 5 μm and smaller than about 100 μm
Claim 6
Dependent Claim
190 words
A process for producing a magnetic recording medium comprising the steps of: providing a non-magnetic support base having a surface; coating said non-magnetic support base surface with an emulsion of magnetic material comprising a large filler having a grain size ranging from about 2 μm to about 30 μm and a small filler having a grain size ranging from about 0.01 μm to about 5 μm; drying said emulsion of magnetic material to form a magnetic layer on said non-magnetic support surface; and subjecting the resulting magnetic recording medium to calendering utilizing calender rolls under conditions such that the pressure between two rolls ranges from 100 Kg/cm to 400 Kg/cm at a temperature ranging from 20° C. to 150° C. resulting in a magnetic layer having a surface roughness controlled such that the maximum value of the arithmetical average roughness is at least about 80 A in the surface roughness pitch region greater than about 300 μm and the maximum value of the arithmetical average roughness is about 40 A to 5 A in the surface roughness pitch region greater than about 5 μm and smaller than about 100 μm
Claim 7
Dependent Claim
43 words
A process for producing a magnetic recording medium, as claimed in claim 4, wherein said large filler has a grain size ranging from 10 μm to 20 μm and said small filler has a grain size ranging from 0.01 μm to 2 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) | 1985-06-28 | 1985-12-28 | 1986-06-29 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1989-06-28 | 1989-12-28 | 1990-06-29 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1993-06-28 | 1993-12-28 | 1994-06-29 | $7700.00 | Window Closed / Lapsed |