US3784378A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Double-exposure method for producing reverse images in photopolymers
Assignee: EIDP Inc
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Filing: 1971-10-18
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Granted: 1974-01-08
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Expires: 1991-10-18
Abstract
Abstract For the production of reverse images, a photosensitive element comprising a polymerizable (or crosslinkable) material and two photoinitiators responsive to different wavelengths of actinic radiation is exposed successively to actinic radiation of wavelengths appropriate for the two photoinitiators. The first exposure is imagewise and the second is nonimagewise. A polymerization inhibitor is present during both exposures. The method is useful in the graphic arts where a positive-working system is required, e.g., for relief or planographic printing plates, direct positive copying films, and the like.
Inventors
- 👤 J Gramas
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 21:06
CPC Classifications
G; G03; G03F; G03F7/00; G03F7/20; G03F7/2022; G03F7/004; G03F7/027; Y; Y10; Y10S; Y10S430/00; Y10S430/1053; Y10S430/1055; Y10S430/106; Y10S430/113
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
43 words
nonimagewise exposing said layer to radiation, said radiation including wavelengths different than those of the radiation used in the step of imagewise exposing and capable of photohardening, in the presence of said inhibitor, the areas that were not exposed in the imagewise exposure.
Claim 2
Dependent Claim
30 words
A process of claim 1 having the additional step of heating the layer to complete polymerization of the areas of the layer that were not exposed in the imagewise exposure.
Claim 3
Dependent Claim
74 words
A process of claim 1 wherein said first free radical generating compound is responsive to radiation of wavelengths greater than 450 nm and said second free radical generating compound is responsive only to radiation of wavelengths less than 450 nm, the step of imagewise exposing being carried out with radiation of wavelengths greater than 450 nm and the step of nonimagewise exposing being carried out with radiation including wavelengths of less than 450 nm.
Claim 4
Dependent Claim
16 words
A process of claim 1 wherein said photosensitive element comprises a sheet support bearing said layer.
Claim 5
Dependent Claim
65 words
A process of claim 1 wherein said step of imagewise exposing comprises exposing said layer to image light from a light source emitting radiation of wavelengths both greater and less than 450 nm, the radiation from said light source being filtered through a filter that passes only radiation of wavelengths greater than 450 nm, said step of nonimagewise exposing being carried out without said filter.
Claim 6
Dependent Claim
19 words
A process of claim 1, wherein said ethylenically unsaturated, addition-polymerizable or crosslinkable material is triethyleneglycol diacrylate or trimeThylolpropane triacrylate.
Claim 7
Dependent Claim
13 words
A process of claim 1, wherein said hydrogen-donor compound is N-phenylglycine or 2-mercaptobenzimidazole.
Claim 8
Dependent Claim
32 words
A process of claim 1, wherein said first free radical generating compound is Erythrosin B or Methylene Blue and said second free radical generating compound is 2-o-chloro-phenyl-4,5-di(m-methoxyphenyl)imidazolyl dimer or benzoin methyl ether.
Claim 9
Dependent Claim
17 words
A process of claim 1, said layer containing a binder of cellulose acetate butyrate or poly(methyl methacrylate).
Claim 10
Dependent Claim
20 words
A process of claim 1, said step of nonimagewise exposure being carried out in the presence of a photohardening inhibitor.
Claim 11
Dependent Claim
11 words
A process of claim 10, said photohardening inhibitor being atmospheric oxygen.
References Cited (Backward Citations)
US3144331A
Cited
US3380825A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-01-07 | 1977-07-09 | 1978-01-08 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-01-07 | 1981-07-09 | 1982-01-08 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-01-07 | 1985-07-09 | 1986-01-08 | $7700.00 | Window Closed / Lapsed |