US4477593A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Sheet printed with invisible inks, developers and erasure compounds _for invisible inks
Assignee: Lockley Services Pty Ltd
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Filing: 1982-03-02
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Granted: 1984-10-16
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Expires: 2002-03-02
Abstract
Abstract The invention relates to a developable surface comprising a carrier layer having thereon at least two deposits of one or more invisible inks in adjacent or overlapping relationship, said deposits in the developed state being unresolvable.
Inventors
- 👤 Roderick P. J. Tomlinson
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 09:06
CPC Classifications
C; C09; C09D; C09D11/00; C09D11/50; B; B41; B41M; B41M3/00; B41M3/14; B41M3/142; C09D10/00; G; G01; G01N; G01N2223/00; G01N2223/07; G01N2223/071; G01N2223/074; G01N2223/0745; G01N2223/10; G01N2223/106; G01N2223/1066; G01N2223/60; G01N2223/635; G01N2223/643; Y; Y10; Y10S; Y10S283/00; Y10S283/901; Y10S428/00; Y10S428/916; Y10T; Y10T428/00; Y10T428/24; Y10T428/24802; Y10T428/24835
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
64 words
A system of developing an invisible ink and erasing the resultant developed ink comprising a surface having applied thereto one or more invisible inks, an applicator fluid including at least a developer compound and an erasure compound, such that, on application of the fluid to the surface, the ink initially becomes visible and subsequently, after a predetermined period of time, reassumes an invisible state.
Claim 2
Independent Claim
64 words
A system of developing an invisible ink and erasing the resultant developed ink comprising a surface having applied thereto one or more invisible inks, an applicator fluid including at least a developer compound and an erasure compound, such that, on application of the fluid to the surface, the ink initially becomes visible and subsequently, after a predetermined period of time, reassumes an invisible state.
Claim 3
Dependent Claim
14 words
A system according to claim 1, wherein the erasure compound is a volatile alkali.
Claim 4
Dependent Claim
14 words
A system according to claim 1, wherein the erasure compound is a volatile amine.
Claim 5
Dependent Claim
27 words
A system according to claim 1, wherein the erasure compound is selected from tetrahydro 2H 1,4 oxazine in a glycol/water vehicle, ammonia, ethylamine, monoethanolamine, diethanolamine, and triethanolamine.
Claim 6
Dependent Claim
20 words
A system according to claim 1, wherein the erasure compound is an acid buffered vehicle and the developer is alkaline.
Claim 7
Dependent Claim
36 words
A system according to claim 5, wherein the pH of the acid buffered vehicle is in the range of 3 to 5 and the pH of the developer is in the range of 9 to 10.
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) | 1987-10-16 | 1988-04-16 | 1988-10-16 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1991-10-16 | 1992-04-16 | 1992-10-16 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1995-10-16 | 1996-04-16 | 1996-10-16 | $7700.00 | Window Closed / Lapsed |