US3960632A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of preparing a dispensing pad for fingerprinting reagents
Assignee: Veriprint Systems Corp
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Filing: 1974-09-26
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Granted: 1976-06-01
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Expires: 1994-09-26
Abstract
Abstract An inkless fingerprinting system comprises a porous, non-yielding reagent pad saturated with a substantially colorless metallic salt solution, preferably based on ferric chloride, and means for applying an organic developer, preferably 8-hydroxyquinoline, to a latent fingerprint obtained by pressing the distal surface of a finger against the reagent pad and transferring the reagent adhering to the ridges of the finger onto a paper or plastic surface. The reagent and the developer interact to form a colored chelate and, thereby, render the fingerprint visible.
Inventors
- 👤 Jerome Gaines
- 👤 Herbert M. Conrad
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 13:18
CPC Classifications
A; A61; A61B; A61B5/00; A61B5/117; A61B5/1171; A61B5/1172
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
125 words
The method of preparing a dispensing pad for fingerprinting reagents, comprising the steps of: preparing a plaster of Paris slurry; dispersing sawdust in said slurry; charging the slurry into a mold, and floating a layer of felt thereon; allowing the slurry to set in said mold; removing the hardened plaster matrix with the felt layer adhering thereto from said mold; drying said matrix at an elevated temperature for a predetermined period; preparing a reagent with metallic ions dispersed in a suitable solvent; submerging said plaster matrix with the felt layer adhering thereto in said reagent to saturate said matrix and said felt layer therewith; and inserting said pad into a fluid-tight pan with said plaster matrix exposed upwardly and said felt layer depending downwardly therefrom.
Claim 2
Independent Claim
125 words
The method of preparing a dispensing pad for fingerprinting reagents, comprising the steps of: preparing a plaster of Paris slurry; dispersing sawdust in said slurry; charging the slurry into a mold, and floating a layer of felt thereon; allowing the slurry to set in said mold; removing the hardened plaster matrix with the felt layer adhering thereto from said mold; drying said matrix at an elevated temperature for a predetermined period; preparing a reagent with metallic ions dispersed in a suitable solvent; submerging said plaster matrix with the felt layer adhering thereto in said reagent to saturate said matrix and said felt layer therewith; and inserting said pad into a fluid-tight pan with said plaster matrix exposed upwardly and said felt layer depending downwardly therefrom.
Claim 3
Dependent Claim
17 words
The method of claim 1, wherein said elevated temperature is less than the boiling point of water.
Claim 4
Dependent Claim
13 words
The method of claim 1, including adding a coloring agent to said slurry.
Claim 5
Dependent Claim
12 words
The method of claim 3, wherein said coloring agent is ferrous oxide.
Claim 6
Dependent Claim
24 words
The method of claim 1, wherein the volume of sawdust added to said plaster slurry is in a proportion of 1 part in 4.
Claim 7
Dependent Claim
19 words
The method of claim 5, wherein said temperature is about 160° F. and said predetermined period is 1 hour.
Claim 8
Dependent Claim
20 words
The method of claim 1, wherein said metallic ions are derived from a ferric salt and said solvent is glycerine.
Claim 9
Dependent Claim
12 words
The method of claim 7, wherein said ferric salt is ferric chloride.
Claim 10
Dependent Claim
14 words
The method of claim 1, wherein said mold has a planar, smooth base surface.
Claim 11
Dependent Claim
13 words
The method of claim 9, wherein said mold is substantially rectangular in plan.
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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) | 1979-06-01 | 1979-12-01 | 1980-06-01 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1983-06-01 | 1983-12-01 | 1984-06-01 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1987-06-01 | 1987-12-01 | 1988-06-01 | $7700.00 | Window Closed / Lapsed |