Patent US4188431A successfully refreshed from Google Patents.
US4188431A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Latent image printing and development
Assignee: Gillette Co LLC
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Filing: 1975-09-24
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Granted: 1980-02-12
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Expires: 1995-09-24
Abstract
Abstract This invention relates to alkali developable, paper-based systems printed with invisible phenolphthalein inks and made reusable through many development cycles by employing critical concentrations of dye reactants in conjunction with a paper having a defined water soluble acidity-alkalinity.
Inventors
- 👤 Phillip E. Sokol
- 👤 Robert F. Farmer
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 16:52
CPC Classifications
G; G09; G09B; G09B3/00; G09B3/02; G09B3/04; B; B41; B41M; B41M3/00; B41M3/001; C; C09; C09D; C09D11/00; C09D11/50; Y; Y10; Y10T; Y10T428/00; Y10T428/24; Y10T428/24802; Y10T428/24835; Y10T428/24934; Y10T428/31504; Y10T428/31971; Y10T428/31993
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
57 words
A reusable paper-based feedback system comprising a paper substrate having a water solubility acidity-alkalinity of from 0.08% acid as sulfur trioxide to 0.05% base as sodium hydroxide, said paper substrate bearing a. a visible image and b. an invisible image derived from printing on said paper substrate an ink comprising from 0.1 to 9.0% by weight phenolphthalein.
Claim 2
Dependent Claim
57 words
A reusable paper-based feedback system comprising a paper substrate having a water solubility acidity-alkalinity of from 0.08% acid as sulfur trioxide to 0.05% base as sodium hydroxide, said paper substrate bearing a. a visible image and b. an invisible image derived from printing on said paper substrate an ink comprising from 0.1 to 9.0% by weight phenolphthalein.
Claim 3
Dependent Claim
21 words
A reusable paper-based feedback system according to claim 1 wherein said paper substrate has a yellowness index of 20 to 50.
Claim 4
Dependent Claim
46 words
A reusable paper-based feedback system according to claim 1 wherein the paper substrate has a water soluble acidity of no more than 0.06% and wherein the invisible image is derived from printing on said paper substrate an ink comprising from 0.5 to 5.0% by weight phenolphthalein.
Claim 5
Dependent Claim
21 words
A reusable paper-based feedback system according to claim 3 wherein said paper substrate has a yellowness index of 20 to 30.
Claim 6
Dependent Claim
43 words
A reusable paper-based feedback system according to claim 1 comprising, in addition, an alkaline developing composition in the form of an aqueous solution of a compound selected from the group consisting of monoethanolamine, propanolamine and water soluble carbonate, phosphate, borate and silicate salts.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1983-02-11 | 1983-08-13 | 1984-02-12 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1987-02-11 | 1987-08-13 | 1988-02-12 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1991-02-11 | 1991-08-13 | 1992-02-12 | $7700.00 | Window Closed / Lapsed |