Abstract A long-wearing silver-halide gelatin offset printing plate having a photosensitive emulsion layer of about 3 mils on a metal base, preferably aluminum, which is subjected to long development, after light exposure, with a tanning developer and which is thereafter baked for from 520 to 30 seconds at a temperature of from 275* C to 375* C to thereby achieve a hardened film of uniform thickness. The thickness of the hardened, baked film at the point of first wear on the printing plate varies from about 3 to 7 microns. In comparison with the number of good quality prints obtainable from heretofore known plates, e.g., 500 to 1,000 prints, the present plate gives from 20,000 to 500,000 good quality prints.
Inventors
👤 Charles E Wheelock
Bibliographic Details
Application Number—
JurisdictionUS
Data Sourcegoogle_patents
Last Synchronized2026-11-04 13:18
CPC Classifications
G; G03; G03F; G03F7/00; G03F7/004; G03F7/06
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
23 words
A long-wearing oleophobic metal base oleophilic silver-halide gelatin offset image printing plate as claimed in claim 1 wherein said metal base is aluminum.
Claim 2
Independent Claim
169 words
A method of making a long-wearing oleophobic metal base oleophilic silver-halide gelatin offset image printing plate comprising: providing a photosensitive silver-halide emulsion layer deposited uniformly from aqueous gelatin medium in a thickness of at least about 2.5 mils up to about 4 mils on an oleophobic metal base; exposing the plate to actinic image information; after exposure developing the plate for at least 10 seconds up to about 300 seconds with a tanning developer; removing the non-exposed portion of the silver-halide gelatin emulsion layer to uncover the portions of the oleophobic metal substrate therebeneath; drying to remove water from said layer and base; and thereafter baking the plate in one or more cycles for a period of time varying between 10 seconds and 520 seconds at a temperature of from 275* C up to 375* C to provide exposed, developed and bake-hardened oleophilic silver-halide gelatin film offset image portions shrunk to a substantially uniform thickness of from about 3 microns to about 10 microns upon said oleophobic metal base.
Claim 3
Dependent Claim
49 words
A method as claimed in claim 3, wherein the silver-halide emulsion layer is provided to a thickness of at least about 3 mils and the exposed, developed, and bake-hardened oleophilic silver-halide gelatin film offset portions are shrunken to a thickness of from about 3 microns to about 7 microns.
Claim 4
Dependent Claim
24 words
A method as claimed in claim 3, wherein the development is for a period of from between about 10 seconds and about 60 seconds.
Claim 5
Dependent Claim
22 words
A method as claimed in claim 3, wherein baking is carried out in at least 2 cycles of about 30 seconds each.
Claim 6
Dependent Claim
48 words
A method as claimed in claim 4, wherein the development is for a period of from between about 60 seconds and 300 seconds and the baking takes place at a temperature of from 275* C and 375* C in at least 2 cycles of about 30 seconds each.