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US3791843A Expired / Lapsed US ⏱️ 0.0 years remaining

Thermomagnetic imaging method

Assignee: Agfa Gevaert AG
•
Filing: 1971-11-03
•
Granted: 1974-02-12
•
Expires: 1991-11-03
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Abstract

Abstract The magentic image receiving surface of a copying 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 2026-10-27 07:58
CPC Classifications
G; G03; G03G; G03G19/00; Y; Y10; Y10S; Y10S101/00; Y10S101/37

Claims Analysis

Total Claims: 9
Claim 1
Independent Claim 12 words
A method as defined in claim 1, wherein said ingredient is FeRh.
Claim 2
Dependent Claim 50 words
A method as defined in claim 1, further comprising the step of maintaining said ingredient below said Neel temperature prior to said exposing step, said temperature changing step comprising heating said first areas of said surface to said Neel temperature and said other temperature being substantially below said Neel temperature.
Claim 3
Dependent Claim 47 words
A method as defined in claim 1, further comprising the step of maintaining said ingredient at said Neel temperature prior to said exposing step, said temperature changing step comprising heating said second areas above said Neel temperature so that said other temperature substantially exceeds said Neel temperature.
Claim 4
Dependent Claim 43 words
A method as defined in claim 1, further comprising the step of maintaining said ingredient prior to said exposing step at a temperature which closely approximates the temperature of one of said first and second areas upon completion of said temperature changing step.
Claim 5
Dependent Claim 20 words
A method as defined in claim 1, further comprising the step of transferring said powder image onto a transfer material.
Claim 6
Dependent Claim 66 words
A method as defined in claim 1, wherein said contacting step comprises contacting the exposed image receiving surface with a coat of pulverulent magnetic toner carried on a donor surface from which said coat the image receiving surface removes toner so that the thus removed toner adheres to said first area of said image receiving surface and the remainder of said coat conStitutes said powder image.
Claim 7
Dependent Claim 70 words
A method as defined in claim 1, further comprising the step of transferring said thermal image of said image recieving surface onto a magnetic layer whose coercive force is less than the coercive force of said ingredient at said Neel temperature, said contacting step comprising placing said transferred thermal image at least once into contact with a pulverulent magnetic toner to thus convert said thermal image into a powder image.
Claim 8
Dependent Claim 23 words
A method as defined in claim 1, wherein said toner consists of pigmentized thermoplastic material and magnetizable carrier for said pigmentized thermoplastic material.
Claim 9
Dependent Claim 35 words
A method as defined in claim 9, further comprising the steps of transferring said powder image onto a transfer material and fixing the transferred powder image to the transfer material in the presence of heat.

References Cited (Backward Citations)

US3472695A Cited
US3613100A Cited
US3566786A Cited
US3562760A Cited
US3598993A Cited
US3582877A Cited

USPTO Annuity & Maintenance Windows

Annuity Stage Window Opens Payment Deadline Surcharge Period Until Estimated Fee Status
3.5 Years (Year 4) 1977-02-11 1977-08-13 1978-02-12 $2000.00 Window Closed / Lapsed
7.5 Years (Year 8) 1981-02-11 1981-08-13 1982-02-12 $3760.00 Window Closed / Lapsed
11.5 Years (Year 12) 1985-02-11 1985-08-13 1986-02-12 $7700.00 Window Closed / Lapsed

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