Patent US4939604A successfully refreshed from Google Patents.
US4939604A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Magnetic recording and reproducing apparatus and a magnetic head used for the apparatus
Assignee: TDK Corp
•
Filing: 1989-03-23
•
Granted: 1990-07-03
•
Expires: 2009-03-23
Abstract
Abstract A magnetic head comprises a slider which holds recording/writing elements at its medium opposing surface constituting a lifting force generating part and the surface area of the medium opposing surface is at most 2 mm 2 . A magnetic recording and reproducing apparatus has such magnetic head which is disposed on a magnetic disk having a magnetic recording layer formed on a rigid substrate while the disk is rotated at a high speed so that magnetic recording and reproducing are conducted between the magnetic head and the magnetic disk, wherein the surface roughness R max of the magnetic disk is at most 100 Å.
Inventors
- 👤 Kazumasa Fukuda
- 👤 Masanori Sakai
- 👤 Joichiro Ezaki
- 👤 Mikio Matsuzaki
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 20:50
CPC Classifications
G; G11; G11B; G11B5/00; G11B5/62; G11B5/73; G11B5/739; G11B5/73911; G11B5/73921; G11B5/74; G11B5/82
Claims Analysis
Total Claims: 19
Claim 1
Independent Claim
109 words
A magnetic recording and reproducing apparatus of a type wherein a magnetic head is disposed on a magnetic disk having a magnetic recording layer formed on a rigid substrate while the disk is rotated at a high speed so that magnetic recording and reproducing are conducted between the magnetic head and the magnetic disk, characterized in that the surface roughness R max of the magnetic disk is at most 100 Å and the surface area of a medium opposing surface of a slider holding reading/writing elements is at most 2 mm 2 , the surface of the slider facing the magnetic disk and constituting a lifting force generating part.
Claim 2
Dependent Claim
109 words
A magnetic recording and reproducing apparatus of a type wherein a magnetic head is disposed on a magnetic disk having a magnetic recording layer formed on a rigid substrate while the disk is rotated at a high speed so that magnetic recording and reproducing are conducted between the magnetic head and the magnetic disk, characterized in that the surface roughness R max of the magnetic disk is at most 100 Å and the surface area of a medium opposing surface of a slider holding reading/writing elements is at most 2 mm 2 , the surface of the slider facing the magnetic disk and constituting a lifting force generating part.
Claim 3
Dependent Claim
24 words
The magnetic recording and reproducing apparatus according to claim 1, wherein said rigid substrate has surface roughness R max of at most 100 Å.
Claim 4
Dependent Claim
18 words
The magnetic recording and reproducing apparatus according to claim 1, wherein said substrate is composed essentially of glass.
Claim 5
Dependent Claim
24 words
The magnetic recording and reproducing apparatus according to claim 1, wherein said rigid substrate is composed essentially of chemically reinforced soda alumino silicate glass.
Claim 6
Dependent Claim
17 words
The magnetic recording and reproducing apparatus according to claim 1, wherein said substrate is made of ceramics.
Claim 7
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 8
Dependent Claim
27 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 its surface layer.
Claim 9
Dependent Claim
27 words
The magnetic recording and reproducing apparatus according to claim 7, wherein the oxide layer and the nitride layer are formed by reactive sputtering or reactive vapor deposition.
Claim 10
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 11
Dependent Claim
52 words
The magnetic recording and reproducing apparatus according to claim 9, 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 12
Dependent Claim
32 words
The magnetic recording and reproducing apparatus according to claim 1, wherein the recording residural magnetization of the magnetic recording layer is composed essentially of a component perpendicular to the magnetic recording layer.
Claim 13
Dependent Claim
35 words
The magnetic recording and reproducing apparatus according to claim 1, wherein the recording residual magnetization of the magnetic recording layer is composed essentially of a component in the same plane as the magnetic recording layer.
Claim 14
Dependent Claim
38 words
A magnetic head which comprises a slider which holds recording/writing elements at its medium opposing surface constituting a lifting force generating part, wherein the surface area of the medium opposing surface is at most 2 mm 2 .
Claim 15
Dependent Claim
38 words
A magnetic head which comprises a slider which holds recording/writing elements at its medium opposing surface constituting a lifting force generating part, wherein the surface area of the medium opposing surface is at most 2 mm 2 .
Claim 16
Dependent Claim
23 words
The magnetic head according to claim 13, wherein the surface area of the medium opposing surface is at most 1 mm 2 .
Claim 17
Dependent Claim
30 words
The magnetic head according to claim 13, wherein the medium opposing surface is formed by the surface of rail portions formed in parallel to the direction of an air stream.
Claim 18
Dependent Claim
20 words
The magnetic head according to claim 13, wherein the medium opposing surface has a tapered plane at an inflow end.
Claim 19
Dependent Claim
23 words
The magnetic head according to claim 13, wherein the medium opposing surface is made flat without a tapered plane at an inflow end.
References Cited (Backward Citations)
US4081846A
Cited
US4803577A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1993-07-02 | 1994-01-01 | 1994-07-03 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1997-07-02 | 1998-01-01 | 1998-07-03 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2001-07-02 | 2002-01-01 | 2002-07-03 | $7700.00 | Window Closed / Lapsed |