US4599658A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Thermo-magnetic recording method
Assignee: Fujifilm Business Innovation Corp
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Filing: 1982-08-24
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Granted: 1986-07-08
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Expires: 2002-08-24
Abstract
Abstract A method of thermo-magnetic recording employs a recording medium of a magnetization material disposed on an insulator. An area on the medium is joule-heated via the application of a voltage across contacting electrodes up to a bias point, and a heat pattern is applied in the form of an image to form a magnetic latent image.
Inventors
- 👤 Koichi Saitoh
- 👤 Teruhiko Itami
- 👤 Toshifumi Kimoto
- 👤 Nobuo Nishimura
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 05:54
CPC Classifications
G; G03; G03G; G03G19/00; G03G19/005
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
114 words
A thermo-magnetic recording method, comprising: providing a magnetic recording medium having a thermally magnetizable ferromagnetic surface layer disposed on an insulating layer; contacting a pair of spaced apart electrodes to said ferromagnetic surface layer in a spaced manner said electrodes traversing said ferromagnetic surface layer and defining a predetermined portion of said ferromagnetic surface layer; applying a voltage to said electrodes causing Joule preheating of said ferromagnetic surface layer; and inputting a heat pattern in the form of an image and applying uniform magnetic field to form a magnetic latent image in said ferromagnetic surface layer; wherein said uniform magnetic field is applied by means of a magnetized layer of said magnetic recording medium.
Claim 2
Dependent Claim
114 words
A thermo-magnetic recording method, comprising: providing a magnetic recording medium having a thermally magnetizable ferromagnetic surface layer disposed on an insulating layer; contacting a pair of spaced apart electrodes to said ferromagnetic surface layer in a spaced manner said electrodes traversing said ferromagnetic surface layer and defining a predetermined portion of said ferromagnetic surface layer; applying a voltage to said electrodes causing Joule preheating of said ferromagnetic surface layer; and inputting a heat pattern in the form of an image and applying uniform magnetic field to form a magnetic latent image in said ferromagnetic surface layer; wherein said uniform magnetic field is applied by means of a magnetized layer of said magnetic recording medium.
Claim 3
Dependent Claim
27 words
A method as claimed in claim 1, wherein said electrodes are sized and disposed such that only a limited area of said ferromagnetic surface layer is heated.
Claim 4
Dependent Claim
15 words
A method as claimed in claim 2, wherein said ferromagnetic surface layer includes chromium dioxide.
Claim 5
Dependent Claim
27 words
A method as claimed in claim 2, wherein said ferromagnetic surface layer is an thin amorphous alloy layer of a rare earth metal - a transition metal.
Claim 6
Dependent Claim
21 words
A method of claimed in claim 1, wherein said heat pattern and said uniform magnetic field are applied immediately after preheating.
Claim 7
Dependent Claim
22 words
A method as claimed in claim 1, wherein said heat pattern and said uniform magnetic field are applied simultaneously with said preheating.
Claim 8
Dependent Claim
23 words
A method as claimed in claim 6, wherein said ferromagnetic surface layer includes chromium dioxide and an adjustable material for an electric conductivity.
Claim 9
Dependent Claim
18 words
A method as claimed in claim 1, including applying said heat pattern by means of a light source.
Claim 10
Dependent Claim
17 words
A method as claimed in claim 1, including applying said uniform magnetic field from an external magnet.
Claim 11
Dependent Claim
25 words
A method as claimed in claim 1, said heat pattern being applied by means of an array of resistance heating elements disposed between said electrodes.
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) | 1989-07-07 | 1990-01-06 | 1990-07-08 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1993-07-07 | 1994-01-06 | 1994-07-08 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1997-07-07 | 1998-01-06 | 1998-07-08 | $7700.00 | Window Closed / Lapsed |