Patent US3869711A successfully refreshed from Google Patents.
US3869711A
Expired / Lapsed
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Magnetic pattern recording
Assignee: International Business Machines Corp
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Filing: 1974-01-25
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Granted: 1975-03-04
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Expires: 1994-01-25
Abstract
Abstract A pattern is recorded on a magnetic medium by passing the medium across a master rotary element having a predetermined pattern of magnetic and nonmagnetic areas. A first magnetic heat magnetizes the medium in a first direction, and a second head that provides a constant DC field then selectively magnetizes the medium in a different direction in those locations where the magnetic areas of the patterned rotary element do not shield the medium from the field.
Inventors
- 👤 William R Bernard
- 👤 Walter S Buslik
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 05:28
CPC Classifications
G; G11; G11B; G11B5/00; G11B5/86; G11B5/865; B; B82; B82Y; B82Y10/00; G11B5/74; G11B5/743
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
147 words
Apparatus for producing a recorded signal on a magnetic medium comprising: a master element having a permanently formed physical pattern of magnetic and nonmagnetic areas of lands and voids respectively on one surface thereof, said pattern not being magnetizable or erasable by electromagnetic means, said lands being formed of soft magnetic material having high permeability and low coercivity and disposed over a nonmagnetic base; means for moving said medium in unison with said master element with substantially no relative motion between said medium and said element, while said element and said medium are maintained in close transducing relation; a magnetic head positioned adjacent to a surface of said master element opposite to said one surface, so that said element is between said medium and said magnetic head, for providing a constant DC field to effectively record on said medium pattern of signals corresponding to said physical pattern.
Claim 2
Dependent Claim
147 words
Apparatus for producing a recorded signal on a magnetic medium comprising: a master element having a permanently formed physical pattern of magnetic and nonmagnetic areas of lands and voids respectively on one surface thereof, said pattern not being magnetizable or erasable by electromagnetic means, said lands being formed of soft magnetic material having high permeability and low coercivity and disposed over a nonmagnetic base; means for moving said medium in unison with said master element with substantially no relative motion between said medium and said element, while said element and said medium are maintained in close transducing relation; a magnetic head positioned adjacent to a surface of said master element opposite to said one surface, so that said element is between said medium and said magnetic head, for providing a constant DC field to effectively record on said medium pattern of signals corresponding to said physical pattern.
Claim 3
Dependent Claim
12 words
Apparatus as in claim 1, wherein said element is a rotary drum.
Claim 4
Dependent Claim
12 words
Apparatus as in claim 2, wherein said medium is a magnetic tape.
Claim 5
Dependent Claim
19 words
Apparatus as in claim 1, wherein said element is a rotary disk, and said medium is a magnetic disk.
Claim 6
Dependent Claim
14 words
Apparatus as in claim 1, wherein said magnetic head provides a constant DC field.
Claim 7
Dependent Claim
36 words
Apparatus as in claim 1, including a second magnetic head for providing a first magnetic field and for uniformly magnetizing said medium in a single direction prior to magnetically coupling said medium with said master element.
Claim 8
Independent Claim
109 words
A method of registering a recorded magnetic pattern on a magnetic medium corresponding to a configured pattern of magnetic and nonmagnetic areas of lands and voids respectively on a nonmagnetizable master element comprising the steps of: premagnetizing the medium in a prescribed direction; placing the premagnetized medium in magnetically coupled relation with said configured pattern; and moving the medium in unison with said master element past a magnetizing head; providing a constant DC field by means of said head, thereby reversing the magnetization of the medium whenever the medium encounters nonmagnetic voids on the master element and thus uniformly magnetizing the medium in selected areas determined by said pattern.
Claim 9
Independent Claim
109 words
A method of registering a recorded magnetic pattern on a magnetic medium corresponding to a configured pattern of magnetic and nonmagnetic areas of lands and voids respectively on a nonmagnetizable master element comprising the steps of: premagnetizing the medium in a prescribed direction; placing the premagnetized medium in magnetically coupled relation with said configured pattern; and moving the medium in unison with said master element past a magnetizing head; providing a constant DC field by means of said head, thereby reversing the magnetization of the medium whenever the medium encounters nonmagnetic voids on the master element and thus uniformly magnetizing the medium in selected areas determined by said pattern.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-03-03 | 1978-09-02 | 1979-03-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-03-03 | 1982-09-02 | 1983-03-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-03-03 | 1986-09-02 | 1987-03-04 | $7700.00 | Window Closed / Lapsed |