Patent US2459039A successfully refreshed from Google Patents.
US3784394A
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Latent image composite master and method
Assignee: 3M Co
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Filing: 1971-05-06
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Granted: 1974-01-08
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Expires: 1991-05-06
Abstract
Abstract In the disclosed method for making a composite master capable of producing both visible and invisible images on a copy or receptor sheet, a first and second set of infrared absorptive images are entered on the obverse, uncoated surface of the master and mirror image deposits of dithiooxamide (DTO) or a derivative thereof corresponding to the second set of images are entered on the reverse surface of the master. The reverse surface is coated with a dye precursor such as a gallate. A wax transfer sheet or the like is used for providing the DTO deposits. The resulting master is capable of providing both visible and invisible entries on a nickel or copper salt-coated receptor sheet by passing the master and receptor through an infrared copying machine.
Inventors
- 👤 L Bildusas
- 👤 W Manske
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 02:51
CPC Classifications
B; B41; B41M; B41M5/00; B41M5/26; B41M5/40; B41M5/48; G; G09; G09B; G09B3/00; G09B3/02; G09B3/04; Y; Y10; Y10S; Y10S101/00; Y10S101/37; Y10S430/00; Y10S430/1053; Y10S430/1055; Y10S430/106; Y10S430/109
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
33 words
A master according to claim 1 wherein said layer comprising said polyhydroxy aromatic iron-complexing compound is coextensive in area with said reverse surface and wherein said mirror image is deposited on said layer.
Claim 2
Dependent Claim
51 words
A master according to claim 1 wherein said poly-hydroxy aromatic iron-complexing compound is a lower alkyl gallate and said dye precursor is an N,N''-di-organo-substituted dithio-oxamide wherein at least one organo radical has the formula R-CH2-, R being selected from the group consisting of an aliphatic, a cycloaliphatic, and an aromatic radical.
Claim 3
Dependent Claim
11 words
A master according to claim 3 wherein said R is phenyl.
Claim 4
Dependent Claim
14 words
A master according to claim 4 wherein said lower alkyl gallate is methyl gallate.
Claim 5
Independent Claim
201 words
A method of forming visible and latent images on a copy sheet comprising a. providing a composite master sheet having on the obverse surface in a first obverse position a first infrared absorptive image and a second infrared absorptive image in a second obverse position, and having on the reverse surface a layer covering at least an area of said reverse surface opposite said first infrared absorptive image, said layer comprising a polyhydroxy aromatic iron-complexing compound, and having deposited on said reverse surface opposite said second infrared absorptive image a mirror image of said second infrared absorptive image, said mirror image comprising a dye precursor selected from dithiooxamide and a derivative thereof, the area of said reverse surface opposite said first infrared absorptive image being substantially free of said dye precursor, b. placing the reverse surface of said master sheet in contact with a copy sheet, said copy sheet containing a metal salt color reactive with the dye precursor on the master sheet, and c. exposing the master sheet to infrared radiation whereby there is produced on said copy sheet a visible image corresponding to said second infrared absorptive image and a latent image corresponding to said first infrared absorptive image.
Claim 6
Dependent Claim
22 words
The method according to claim 6 wherein said latent image is subsequently rendered visible by means of treatment with an iron salt.
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) | 1977-01-07 | 1977-07-09 | 1978-01-08 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-01-07 | 1981-07-09 | 1982-01-08 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-01-07 | 1985-07-09 | 1986-01-08 | $7700.00 | Window Closed / Lapsed |