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US4663676A Expired / Lapsed US ⏱️ 0.0 years remaining

Return to zero vertical magnetic recording system

Assignee: International Business Machines Corp
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Filing: 1985-09-13
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Granted: 1987-05-05
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Expires: 2005-09-13
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Abstract

Abstract A return-to-zero (RZ) vertical digital magnetic recording method and apparatus comprising a selectively magnetizable recording medium which includes a recording layer of magnetic material having a low vertical remanence. A magnetic recording head is positioned in close proximity to the recording medium, and relative motion is produced between the recording medium and the recording head. To record data, the recording head is energized with one short duration current pulse for each unit of data to be recorded. The resulting bipolar magnetic write field closes substantially perpendicular through the recording medium thereby producing, in the medium, a similarly bipolar flux configuration having the magnetic transition centered about the gap of the magnetic recording head. Data is represented by these transitions in RZ vertical magnetic recording.

Inventors

  • 👤 Otto Voegeli

Bibliographic Details

Application Number —
Jurisdiction US
Data Source google_patents
Last Synchronized 2026-11-04 01:44
CPC Classifications
G; G11; G11B; G11B5/00; G11B5/02; G11B5/09

Claims Analysis

Total Claims: 17
Claim 1
Independent Claim 94 words
A vertical magnetic recording method comprising the steps of: providing a magnetic recording medium having low vertical remanence; positioning a magnetic transducer having means for producing a bipolar magnetic field and a recording gap so that said recording gap is in close proximity to said magnetic recording medium; producing relative motion between said magnetic transducer and said magnetic recording medium; and energizing said means for producing a bipolar magnetic field with a unidirectional recording current impulse of short duration to write a bipolar recorded transition beneath said recording gap in said magnetic recording medium.
Claim 2
Dependent Claim 94 words
A vertical magnetic recording method comprising the steps of: providing a magnetic recording medium having low vertical remanence; positioning a magnetic transducer having means for producing a bipolar magnetic field and a recording gap so that said recording gap is in close proximity to said magnetic recording medium; producing relative motion between said magnetic transducer and said magnetic recording medium; and energizing said means for producing a bipolar magnetic field with a unidirectional recording current impulse of short duration to write a bipolar recorded transition beneath said recording gap in said magnetic recording medium.
Claim 3
Dependent Claim 41 words
The vertical magnetic recording method according to claim 1 wherein said energizing step comprises energizing said means for producing a magnetic field with successive ones of said unidirectional current impulses produced in a mode in which impulses have the same polarity.
Claim 4
Dependent Claim 50 words
The vertical magnetic recording method according to claim 1 wherein said energizing step comprises energizing said means for producing a bipolar magnetic field with successive ones of said unidirectional current impulses produced in a mode in which said impulses alternate in polarity between a positive impulse and a negtaive impulse.
Claim 5
Dependent Claim 31 words
The vertical magnetic recording method according to claim 1 wherein said positioning step comprises positioning said magnetic transducer so that said recording gap is substantially in contact with said recording medium.
Claim 6
Dependent Claim 42 words
The vertical magnetic recording method according to claim 1 wherein said unidirectional current impulse has a duration which is short relative to the spacing between adjacent recorded transitions divided by said relative velocity between said magnetic transducer and said magnetic recording medium.
Claim 7
Dependent Claim 44 words
The vertical magnetic recording method according to claim 1 wherein said unidirectional current impulse has a duration not substantially greater than the length of the pole pieces forming said recording gap divided by the velocity of said relative motion of said magnetic recording medium.
Claim 8
Dependent Claim 23 words
The vertical magnetic recording method according to claim 1 wherein said magnetic recording medium has a vertical remanence of less than 20 percent.
Claim 9
Dependent Claim 164 words
A vertical magnetic recording system for recording magnetic field signals representing information on an associated recording medium, said system comprising a selectively magnetizable recording medium, at least one recording head, means for producing relative motion between the recording medium and the recording head, and means for supplying signals representing information to the recording head for recording upon the medium, the improvement comprising: said recording medium having a recording layer of magnetic material thereon, said recording layer of magnetic material having low vertical remanence; and said means for supplying signals representing information supplying one unidirectional current impulse of short duration to said recording head for each unit of information to be recorded upon said recording medium wherein the direction of the magnetic recording field applied to said recording layer of said recording medium is substantially perpendicular to the surface of said recording medium such that the magnetic flux passes transversely through said recording layer whereby the magnetic recording is produced in the vertical recording mode.
Claim 10
Dependent Claim 164 words
A vertical magnetic recording system for recording magnetic field signals representing information on an associated recording medium, said system comprising a selectively magnetizable recording medium, at least one recording head, means for producing relative motion between the recording medium and the recording head, and means for supplying signals representing information to the recording head for recording upon the medium, the improvement comprising: said recording medium having a recording layer of magnetic material thereon, said recording layer of magnetic material having low vertical remanence; and said means for supplying signals representing information supplying one unidirectional current impulse of short duration to said recording head for each unit of information to be recorded upon said recording medium wherein the direction of the magnetic recording field applied to said recording layer of said recording medium is substantially perpendicular to the surface of said recording medium such that the magnetic flux passes transversely through said recording layer whereby the magnetic recording is produced in the vertical recording mode.
Claim 11
Dependent Claim 29 words
The vertical magnetic recording system according to claim 8 wherein successive ones of said unidirectional current impulses are produced in a mode in which impulses have the same polarity.
Claim 12
Dependent Claim 36 words
The vertical magnetic recording system according to claim 8 wherein successive ones of said unidirectional current impulses are produced in a mode in which impulses alternate in polarity between a positive impulses and a negative impulses.
Claim 13
Dependent Claim 22 words
The vertical magnetic recording system according to claim 8 wherein the recording head is positioned substantially in contact with the recording medium.
Claim 14
Dependent Claim 42 words
The vertical magnetic recording system according to claim 8 wherein said unidirectional current impulse has a duration which is short relative to the spacing between adjacent recorded transitions divided by said relative velocity between said recording head and said magnetic recording medium.
Claim 15
Dependent Claim 47 words
The vertical magnetic recording system according to claim 8 wherein said unidirectional current impulse has a duration not substantially greater than the length of the pole pieces of said recording head divided by the velocity of said relative motion between said recording medium and said recording head.
Claim 16
Dependent Claim 25 words
The vertical magnetic recording system according to claim 8 wherein said recording layer of magnetic material has a vertical remanence of less than 20 percent.
Claim 17
Dependent Claim 18 words
The vertical magnetic recording system according to claim 8 wherein said recording head produces a bipolar magnetic field.

References Cited (Backward Citations)

US4251842A Cited
US4286299A Cited
US4390907A Cited
JPS56163517A Cited
DE3120549A1 Cited
US4442159A Cited

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

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