Patent US1944958A successfully refreshed from Google Patents.
Patent US4751176A successfully refreshed from Google Patents.
US4751176A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Preformed silver halides for photothermographic system
Assignee: Eastman Kodak Co
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Filing: 1985-09-06
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Granted: 1988-06-14
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Expires: 2005-09-06
Abstract
Abstract Method for preparing photosensitive silver halide crystals. A binder resin, a source of halide ions, and a source of silver ions are dissolved in an organic solvent, e.g., ethanol. Silver halide nuclei will then form. Additional source of halide ions and additional source of silver ions can be added to the solution in incremental additions, so that the initially-formed silver halide nuclei will grow. Upon removal of the solvent, the silver halide crystals will exist in a dry state, entrapped in the binder resin. Silver halide crystals formed and grown in this manner can be used to prepare photothermographic imaging compositions, which compositions will exhibit higher speed than photothermographic imaging compositions containing silver halide crystals grown according to conventional methods.
Inventors
- 👤 Oanh V. Pham
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 14:59
CPC Classifications
G; G03; G03C; G03C1/00; G03C1/494; G03C1/498; G03C1/49818; G03C1/005; G03C1/015
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
119 words
A method of preparing a photosensitive heat-processable photographic material comprising the steps of (a) forming a radiation-sensitive silver halide in the presence of a resin by introducing an ionizable silver salt, an ionizable halide, and the resin into an inert organic solvent to form initial silver halide nuclei, introducing additional ionizable silver salt and additional ionizable halide into said solvent in at least one incremental addition so that additional silver halide nuclei will not form more rapidly than the initial silver halide nuclei can grow, (b) adding the radiation-sensitive silver halide so formed to an oxidation-reduction image-forming systems comprising (1) a light-insensitive reducible metal compound, and (2) a reducing agent therefor, and (c) coating the mixture on a support.
Claim 2
Independent Claim
119 words
A method of preparing a photosensitive heat-processable photographic material comprising the steps of (a) forming a radiation-sensitive silver halide in the presence of a resin by introducing an ionizable silver salt, an ionizable halide, and the resin into an inert organic solvent to form initial silver halide nuclei, introducing additional ionizable silver salt and additional ionizable halide into said solvent in at least one incremental addition so that additional silver halide nuclei will not form more rapidly than the initial silver halide nuclei can grow, (b) adding the radiation-sensitive silver halide so formed to an oxidation-reduction image-forming systems comprising (1) a light-insensitive reducible metal compound, and (2) a reducing agent therefor, and (c) coating the mixture on a support.
Claim 3
Dependent Claim
38 words
The method of claim 1 wherein the insert organic solvent in selected from the group consisting of alcohols having from 1 to 4 carbon atoms, ketones having from 1 to 4 carbon atoms, benzene, toluene, and mixtures thereof.
Claim 4
Dependent Claim
12 words
The method of claim 2 wherein the inert organic solvent is ethanol.
Claim 5
Dependent Claim
20 words
The method of claim 1 wherein the ionizable halide is an organic halide having from 1 to 12 carbon atoms.
Claim 6
Dependent Claim
21 words
The method of claim 4 wherein the ionizable halide is selected from the group consisting of organic bromides and organic chlorides.
Claim 7
Dependent Claim
17 words
The method of claim 1 wherein the ionizable silver salt is in the form of particulate material.
Claim 8
Dependent Claim
12 words
The method of claim 1 wherein the resin is a polyvinyl acetal.
Claim 9
Dependent Claim
11 words
The method of claim 7 wherein the resin is polyvinyl butyral.
Claim 10
Dependent Claim
24 words
The method of claim 1 further including the steps of washing the silver halide solution in water and recovering silver halide entrapped in resin.
Claim 11
Dependent Claim
75 words
The method of claim 9 and further including the step of redissolving the resin entrapping the dry silver halide grains, adding more ionizable silver salt or more ionizable halide or both to said solution, thereby causing the silver halide grain to grow, washing the silver halide solution in water, and recovering silver halide entrapped in resin, said recovered silver halide having grain size larger than that of the silver halide whose entrapping resin was redissolved.
Claim 12
Dependent Claim
26 words
The method of claim 10 wherein both the ionizable silver halide and the ionizable halide are added in at least one incremental addition to the solution.
Claim 13
Dependent Claim
19 words
The method of claim 1 wherein each incremental addition contains equal or substantially equal portions of ionizable silver salt.
Claim 14
Dependent Claim
18 words
The method of claim 1 wherein each incremental addition contains equal or substantially equal portions of ionizable halide.
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) | 1991-06-14 | 1991-12-14 | 1992-06-14 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-06-14 | 1995-12-14 | 1996-06-14 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-06-14 | 1999-12-14 | 2000-06-14 | $7700.00 | Window Closed / Lapsed |