US3845306A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Thermomagnetic imaging apparatus
Assignee: Agfa Gevaert AG
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Filing: 1973-10-18
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Granted: 1974-10-29
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Expires: 1993-10-18
Abstract
Abstract The magnetic image receiving surface of a thermomagnetic imaging apparatus is provided with a layer of FeRh or an analogous ingredient which is antiferromagnetic above and below its Neel temperature but exhibits a pronounced coercive force at the Neel temperature. The image receiving surface is moved past an exposure station to receive a thermal image of an original. The exposing step may involve heating selected areas of the image receiving surface to Neel temperature in accordance with the image pattern of the original or heating selected areas of the image receiving surface to above the Neel temperature while the remaining areas remain at Neel temperature. The resulting thermal image is converted with magnetic toner into a powder image, either on the image receiving surface or upon transfer onto an auxiliary surface, and the powder image is transferred onto and fused to paper or another transfer material.
Inventors
- 👤 J Kohlmannsperger
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 20:29
CPC Classifications
G; G03; G03G; G03G19/00
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
109 words
In an apparatus for reproducing images of originals on transfer material, such as paper, a combination comprising a mobile image receiving surface containing an ingredient which is antiferromagnetic at temperatures above and below the Neel temperature thereof, whose Neel temperature exceeds room temperature, and which exhibits a pronounced coercive force at said Neel temperature; and means for exposing thermal images of originals onto said surface, including means for changing the temperature of said surface in accordance with the image pattern of an original so that said surface exhibits first areas which are maintained at said Neel temperature and second areas which are maintained at other than said Neel temperature.
Claim 2
Dependent Claim
109 words
In an apparatus for reproducing images of originals on transfer material, such as paper, a combination comprising a mobile image receiving surface containing an ingredient which is antiferromagnetic at temperatures above and below the Neel temperature thereof, whose Neel temperature exceeds room temperature, and which exhibits a pronounced coercive force at said Neel temperature; and means for exposing thermal images of originals onto said surface, including means for changing the temperature of said surface in accordance with the image pattern of an original so that said surface exhibits first areas which are maintained at said Neel temperature and second areas which are maintained at other than said Neel temperature.
Claim 3
Dependent Claim
20 words
A combination as defined in claim 1, further comprising means for normally maintaining said surface at a predetermined starting temperature.
Claim 4
Dependent Claim
60 words
A combination as defined in claim 2, further comprising means for moving said surface in a predetermined direction, said means for maintaining said surface at said starting temperature comprising means for cooling said surface upstream of said exposing means, as considered in said direction, and said temperature changing means comprising means for heating said first areas to said Neel temperature.
Claim 5
Dependent Claim
60 words
A combination as defined in claim 1, further comprising means for moving said surface in a predetermined direction, developing means located downstream of said exposing means as considered in said direction and including means for applying to said surface a pulverulent magnetic toner whereby said toner adheres to said first areas to convert said thermal image into a powder image.
Claim 6
Dependent Claim
29 words
A combination as defined in claim 4, further comprising means for transferring said powder image onto a transfer material downstream of said developing means, as considered in said direction.
Claim 7
Dependent Claim
26 words
A combination as defined in claim 5, further comprising cleaning means for removing remnants of toner from said surface intermediate said transferring and said exposing means.
Claim 8
Dependent Claim
135 words
A combination as defined in claim 1, further comprising means for moving said suRface in a predetermined direction, an auxiliary surface including a layer of permanently magnetized material in contact with successive increments of said image or receiving surface, and means for applying to said auxiliary surface a coat of pulverulent magnetic toner upstream of the region of contact between said surfaces, the coercive force of said permanently magnetized material being less than the coercive force of said first areas of said image receiving surface so that the latter removes from said coat a first powder image and the residue of said coat constitutes a second powder image of an original, one of said powder images being a positive image and the other of said powder images being a negative image of the respective original.
Claim 9
Dependent Claim
37 words
A combination as defined in claim 7, further comprising means for transferring one of said powder images from the respective surface onto a transfer material and means for fixing the transferred powder image to the transfer material.
Claim 10
Dependent Claim
163 words
A combination as defined in claim 1, further comprising means defining a path for moving transfer material, an auxiliary surface disposed between said path and said image receiving surface and having a layer of magnetic material with a coercive force which is less than the coercive force of said ingredient at said Neel temperature, means for moving said auxiliary surface between a first position of contact with said image receiving surface so as to effect the transfer of a thermal image onto said auxiliary surface and a second position of contact with the transfer material in said path, and developing means including a source of pulverulent magnetic toner and means for applying such toner to the thermal image on said auxiliary surface upstream of the region of contact between said auxiliary surface and transfer material in the second position of said auxiliary surface so that the transferred thermal image is converted into a powder image which is thereupon accepted by said transfer material.
Claim 11
Dependent Claim
30 words
A combination as defined in claim 9, further comprising means for cleaning said auxiliary surface between said region and said developing means in the second position of said auxiliary surface.
Claim 12
Dependent Claim
29 words
A combination as defined in claim 9, further comprising means for demagnetizing said layer on said auxiliary surface prior to movement of said auxiliary surface to said first position.
Claim 13
Dependent Claim
19 words
A combination as defined in claim 9, further comprising means for stabilizing the powder image on said transfer material.
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) | 1977-10-28 | 1978-04-29 | 1978-10-29 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-10-28 | 1982-04-29 | 1982-10-29 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-10-28 | 1986-04-29 | 1986-10-29 | $7700.00 | Window Closed / Lapsed |