US5017226A
Expired / Lapsed
US
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Ink and method for the development of concealed images
Assignee: AB Dick Co
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Filing: 1988-10-03
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Granted: 1991-05-21
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Expires: 2008-10-03
Abstract
Abstract Disclosed is a system for developing latent images on alkali-based or acid-based paper stock which has been marked with a water-soluble oxidizing agent to form a concealed image. In the system, a marking composition is applied to said paper stock which comprises (a) A water-soluble iodide, (b) Acetic acid, (c) A water-soluble reducing agent, and (d) Water. Preferably, the reducing agent is ascorbic acid and preferably the marking composition also comprises a water-soluble dye.
Inventors
- 👤 Michael Kulisz
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 19:32
CPC Classifications
B; B41; B41M; B41M3/00; B41M3/001; Y; Y10; Y10S; Y10S283/00; Y10S283/901
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
88 words
A marking material for use in developing concealed images which have been formed from a water-soluble oxidizing agent on either alkali-based or acid-based paper stock which contains starch, polyvinyl alcohol, or a mixture thereof, wherein said marking material comprises: (a) a water-soluble iodide; (b) acetic acid; (c) a water-soluble reducing agent; (d) a water-soluble or water-dispersible dye or pigment; and (e) water, wherein the amount of the reducing agent is sufficient to maintain essentially all of the iodide in reduced state prior to application to said paper stock.
Claim 2
Dependent Claim
88 words
A marking material for use in developing concealed images which have been formed from a water-soluble oxidizing agent on either alkali-based or acid-based paper stock which contains starch, polyvinyl alcohol, or a mixture thereof, wherein said marking material comprises: (a) a water-soluble iodide; (b) acetic acid; (c) a water-soluble reducing agent; (d) a water-soluble or water-dispersible dye or pigment; and (e) water, wherein the amount of the reducing agent is sufficient to maintain essentially all of the iodide in reduced state prior to application to said paper stock.
Claim 3
Dependent Claim
14 words
The marking material of claim 1 wherein the water-soluble reducing agent comprises ascorbic acid.
Claim 4
Dependent Claim
10 words
The marking material of claim 2 comprising a tetrazine dye.
Claim 5
Dependent Claim
37 words
The marking material of claim 4 comprising about 2 percent acetic acid, about 4 percent potassium iodide, about 0.2 percent tetrazine dye, about 0.025 percent ascorbic acid, and about 0.05 percent preservative, all percentages being by weight.
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) | 1994-05-20 | 1994-11-19 | 1995-05-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1998-05-20 | 1998-11-19 | 1999-05-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2002-05-20 | 2002-11-19 | 2003-05-21 | $7700.00 | Window Closed / Lapsed |