US4918556A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Magnetic disk recording and reproducing apparatus
Assignee: TDK Corp
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Filing: 1988-08-17
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Granted: 1990-04-17
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Expires: 2008-08-17
Abstract
Abstract A magnetic recording and reproducing apparatus of a type wherein a magnetic disk having a magnetic recording layer formed on a rigid substrate is rotatable at a high speed and a magnetic head is disposed on the surface of the disk so that magnetic recording and reproduction are conducted by the head while rotating the disk at a high speed, wherein the surface roughness R max of the magnetic disk is adjusted at a level of at most 100 Å, and the flying height of the magnetic head at the initiation of flying is adjusted at a level within a range of from 0.01 to 0.04 μm.
Inventors
- 👤 Joichiro Ezaki
- 👤 Kazumasa Fukuda
- 👤 Masanori Sakai
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 04:25
CPC Classifications
G; G11; G11B; G11B5/00; G11B5/48; G11B5/58; G11B5/60; G11B5/6005; G11B5/012; G11B5/74; G11B5/82
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
107 words
A magnetic recording and reproducing apparatus of a type wherein a magnetic disk having a magnetic recording layer formed on a rigid substrate is rotatable at a high speed and a magnetic head is disposed on the surface of the disk so that magnetic recording and reproduction are conducted by the head while rotating the disk at a high speed, wherein the surface roughness R max of the magnetic disk is adjusted at a level of at most 100 Å, and the flying height of the magnetic head at the initiation of flying is adjusted at a level within a range of from 0.01 to 0.04 μm.
Claim 2
Dependent Claim
107 words
A magnetic recording and reproducing apparatus of a type wherein a magnetic disk having a magnetic recording layer formed on a rigid substrate is rotatable at a high speed and a magnetic head is disposed on the surface of the disk so that magnetic recording and reproduction are conducted by the head while rotating the disk at a high speed, wherein the surface roughness R max of the magnetic disk is adjusted at a level of at most 100 Å, and the flying height of the magnetic head at the initiation of flying is adjusted at a level within a range of from 0.01 to 0.04 μm.
Claim 3
Dependent Claim
33 words
The magnetic recording and reproducing apparatus according to claim 1, wherein the flying height at the initiation of flying is adjusted at a level within a range of from 0.02 to 0.03 μm.
Claim 4
Dependent Claim
46 words
The magnetic recording and reproducing apparatus according to claim 1, wherein the flying height of the magnetic head at the inner most cylinder of the magnetic disk is adjusted at a level between said flying height at the initiation of flying and a few times thereof.
Claim 5
Dependent Claim
24 words
The magnetic recording and reproducing apparatus according to claim 1, wherein said substrate has a surface roughness R max of at most 100 Å.
Claim 6
Dependent Claim
18 words
The magnetic recording and reproducing apparatus according to claim 1, wherein said substrate is composed essentially of glass.
Claim 7
Dependent Claim
24 words
The magnetic recording and reproducing apparatus according to claim 1, wherein said substrate is composed essentially of a chemically reinforced soda alumino silicate glass.
Claim 8
Dependent Claim
17 words
The magnetic recording and reproducing apparatus according to claim 1, wherein said substrate is made of ceramics.
Claim 9
Dependent Claim
20 words
The magnetic recording and reproducing apparatus according to claim 1, wherein the magnetic recording layer is formed by vacuum depositing.
Claim 10
Dependent Claim
29 words
The magnetic recording and reproducing apparatus according to claim 1, wherein the magnetic recording layer constitutes an oxide layer or a nitride layer at least at its surface layer.
Claim 11
Dependent Claim
27 words
The magnetic recording and reproducing apparatus according to claim 9, wherein the oxide layer and the nitride layer are formed by reactive sputtering or reactive vapor deposition.
Claim 12
Dependent Claim
23 words
The magnetic recording and reproducing apparatus according to claim 1, wherein the magnetic recording layer has an oxidized coating film at its surface.
Claim 13
Dependent Claim
52 words
The magnetic recording and reproducing apparatus according to claim 11, wherein the oxidized coating film is formed by oxidizing the surface of the magnetic recording layer composed of a metal or alloy comprising at least one member selected from the group consisting of iron, cobalt and nickel, by e.g. reactive plasma treatment.
Claim 14
Dependent Claim
31 words
The magnetic recording and reproducing apparatus according to claim 1, wherein the recording residual magnetization of the magnetic disk is composed essentially of a component perpendicular to the magnetic recording layer.
Claim 15
Dependent Claim
34 words
The magnetic recording and reproducing apparatus according to claim 1, wherein the recording residual magnetization of the magnetic disk is composed essentially of a component in the same plane as the magnetic recording layer.
References Cited (Backward Citations)
US4605977A
Cited
US4853810A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1993-04-16 | 1993-10-16 | 1994-04-17 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1997-04-16 | 1997-10-16 | 1998-04-17 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2001-04-16 | 2001-10-16 | 2002-04-17 | $7700.00 | Window Closed / Lapsed |