Patent US4070190A successfully refreshed from Google Patents.
US4070190A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process for producing photographic silver halide emulsions having a core/shell structure
Assignee: EIDP Inc
•
Filing: 1976-08-23
•
Granted: 1978-01-24
•
Expires: 1996-08-23
Abstract
Abstract The invention is a process of producing a lithographic silver halide emulsion having a core/shell structure exhibiting improved halftone dot quality and increased photographic speed, comprising: (1) precipitating a silver chloride emulsion in a protective colloid, (2) converting said silver chloride emulsion to a silver bromide emulsion, and (3) precipitating a silver chloride shell on the surfaces of the silver bromide grains.
Inventors
- 👤 Wolfgang Friedrich
- 👤 Horst Friedel
- 👤 Erhard Jury
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 05:52
CPC Classifications
G; G03; G03C; G03C1/00; G03C1/005; G03C1/015; G03C1/035; G03C2001/03517; G03C2001/03523; G03C2001/03535; G03C2001/03558; Y; Y10; Y10S; Y10S430/00; Y10S430/15
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
60 words
A process for producing a light-sensitive lithographic silver halide emulsion with a core/shell structure exhibiting improved halftone dot quality and increased photographic speed, comprising: (1) precipitating a silver chloride emulsion in a protective colloid, (2) converting said silver chloride emulsion into a silver bromide emulsion, and (3) precipitating a silver chloride shell on the surfaces of the silver bromide grains.
Claim 2
Dependent Claim
60 words
A process for producing a light-sensitive lithographic silver halide emulsion with a core/shell structure exhibiting improved halftone dot quality and increased photographic speed, comprising: (1) precipitating a silver chloride emulsion in a protective colloid, (2) converting said silver chloride emulsion into a silver bromide emulsion, and (3) precipitating a silver chloride shell on the surfaces of the silver bromide grains.
Claim 3
Dependent Claim
102 words
A process for producing a light-sensitive lithographic silver halide emulsion with a core/shell structure exhibiting improved halftone dot quality and increased photographic speed, comprising: (1) precipitating a silver chloride emulsion in a protective colloid, (2) converting said silver chloride emulsion into a silver bromide emulsion, and (3) in the presence of chloride liberated in the aforesaid conversion adding silver nitrate solution to the unwashed converted silver bromide emulsion to precipitate silver chloride on the surface of the silver bromide grains, to produce an emulsion containing grains in which a core of converted silver bromide is coated with a shell of silver chloride.
Claim 4
Dependent Claim
102 words
A process for producing a light-sensitive lithographic silver halide emulsion with a core/shell structure exhibiting improved halftone dot quality and increased photographic speed, comprising: (1) precipitating a silver chloride emulsion in a protective colloid, (2) converting said silver chloride emulsion into a silver bromide emulsion, and (3) in the presence of chloride liberated in the aforesaid conversion adding silver nitrate solution to the unwashed converted silver bromide emulsion to precipitate silver chloride on the surface of the silver bromide grains, to produce an emulsion containing grains in which a core of converted silver bromide is coated with a shell of silver chloride.
Claim 5
Dependent Claim
31 words
The process of claim 2 wherein the quantity of precipitated silver chloride is formulated so that at the end of the precipitation the chloride molar fraction amounts to at least 50%.
Claim 6
Dependent Claim
40 words
The process of claim 2 wherein the quantity of silver chloride precipitated on the surface of the silver bromide grains is formulated so that at the end of the precipitation the chloride/bromide molar ratio is located between 70/30 and 90/10.
Claim 7
Dependent Claim
62 words
The process of claim 2 wherein in Step 2 conversion of the silver chloride emulsion into a silver bromide emulsion is performed by contacting the silver chloride emulsion with an aqueous bromide solution containing about 1 mole percent of a water-soluble iodide whereby the silver bromide cores of the grains of the emulsion will contain about 1 mole percent of silver iodide.
Claim 8
Dependent Claim
55 words
The process of claim 2 wherein in Step 3 a solution of a water-soluble chloride is added simultaneously with the silver nitrate solution, said chloride solution containing about 1 mole percent of a water-soluble iodide, whereby the silver chloride shells of the grains of the emulsion will contain about 1 mole percent of silver iodide.
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) | 1981-01-23 | 1981-07-25 | 1982-01-24 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1985-01-23 | 1985-07-25 | 1986-01-24 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1989-01-23 | 1989-07-25 | 1990-01-24 | $7700.00 | Window Closed / Lapsed |