Patent US3632898A successfully refreshed from Google Patents.
US3632898A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Thermomagnetic copying of magnetic records with cooling of copy medium carrier
Assignee: Memorex Corp
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Filing: 1969-06-16
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Granted: 1972-01-04
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Expires: 1989-06-16
Abstract
Abstract This application discloses a method and apparatus for copying magnetic signals from an original tape to a copy tape which are made from magnetic materials of high and low Curie point, respectively. The two tapes are unwound and moved through a transfer zone and then rewound separately. In the transfer zone, the plastic carrier of the copy tape is cooled while the magnetic coating of the copy tape is heated to its Curie point by radiation passing to the copy tape through the original tape.
Inventors
- 👤 Albert E Slade
- 👤 John J Newman
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 16:43
CPC Classifications
G; G11; G11B; G11B5/00; G11B5/86; G11B5/865; G03; G03G; G03G19/00
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
162 words
The method of producing a copy of magnetic records from an original magnetic recording medium of high Curie point magnetic material to a copy medium which has a coating of low Curie point magnetic material on a carrier said method comprising: A. continuously moving said original medium and said copy medium through a transfer zone while maintaining said media in contact with each other in said zone; B. continuously heating said coating of said copy medium in said transfer zone to at least about the Curie point of said low Curie point material, and; C. simultaneously cooling said carrier of said copy medium in said zone to a temperature below the Curie point of said low Curie point material and over an area which includes and is larger than the area over which said coating is heated by contacting said carrier with a high thermal conductivity metal, thereby maintaining a thermal gradient through the copy medium while said copy medium is heated.
Claim 2
Independent Claim
162 words
The method of producing a copy of magnetic records from an original magnetic recording medium of high Curie point magnetic material to a copy medium which has a coating of low Curie point magnetic material on a carrier said method comprising: A. continuously moving said original medium and said copy medium through a transfer zone while maintaining said media in contact with each other in said zone; B. continuously heating said coating of said copy medium in said transfer zone to at least about the Curie point of said low Curie point material, and; C. simultaneously cooling said carrier of said copy medium in said zone to a temperature below the Curie point of said low Curie point material and over an area which includes and is larger than the area over which said coating is heated by contacting said carrier with a high thermal conductivity metal, thereby maintaining a thermal gradient through the copy medium while said copy medium is heated.
Claim 3
Dependent Claim
23 words
The method of claim 1 in which said step of heating said coating is performed by irradiating said coating through said original medium.
Claim 4
Dependent Claim
34 words
The method of claim 2 in which said step of cooling said carrier is performed by contacting said carrier in said zone with a body of high thermal conductivity and siMultaneously cooling said body.
Claim 5
Dependent Claim
65 words
The method of claim 3 in which said low Curie point magnetic material is chromium dioxide, said step of heating said coating is performed by heating said coating to a temperature between about 0* and 20* C. above the Curie point of said chromium dioxide, and said step of cooling said carrier is performed by maintaining said body at a temperature less than 20* C.
Claim 6
Dependent Claim
64 words
The method of claim 1 in which said step of moving said original and copy media through said transfer zone is performed by supporting said original and copy media on separate supply reels, unwinding said media from said supply reels, passing said media in unwound condition through said transfer zone in contact with each other and winding up said media on separate takeup reels.
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) | 1975-01-03 | 1975-07-05 | 1976-01-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-01-03 | 1979-07-05 | 1980-01-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-01-03 | 1983-07-05 | 1984-01-04 | $7700.00 | Window Closed / Lapsed |