Method of imaging a lithographic printing plate
AssigneeEastman Kodak Company
InventorsCharles D. DeBoer, Neil F. Haley
Life of this patent
Estimating the term…
Abstract
A lithographic printing plate that has an imaging layer that comprises an admixture of (1) a resole resin, (2) a novolac resin, (3) a latent Bronsted acid and (4) an infrared absorber; that is sensitive to both ultraviolet and infrared radiation; and that is capable of functioning in either a positive-working or negative-working manner is imagewise exposed with a laser diode that emits a high-intensity infrared laser beam which provides enhanced image sharpness.
Claims20
A method of imaging a lithographic printing plate;
- said method comprising the steps of:
- (I) providing a lithographic printing plate comprising a support and an imaging layer that is sensitive to both ultraviolet and infrared radiation and capable of functioning in either a positive-working or negative-working manner;
- said imaging layer comprising an admixture of (1) a resole resin, (2) a novolac resin, (3) a latent Bronsted acid and (4) an infrared absorber;
- and
- (II) imagewise exposing said imaging layer with a high-intensity laser diode emitting an infrared laser beam with an intensity at the surface of said imaging layer of at least about 0.2 milliwatts per square micrometer.
A method of imaging a lithographic printing plate;
- said method comprising the steps of:
- (I) providing a lithographic printing plate comprising a support and an imaging layer that is sensitive to both ultraviolet and infrared radiation and capable of functioning in either a positive-working or negative-working manner;
- said imaging layer comprising an admixture of (1) a resole resin, (2) a novolac resin, (3) a latent Bronsted acid and (4) an infrared absorber;
- (II) imagewise exposing said imaging layer with a high-intensity laser diode emitting an infrared laser beam with an intensity at the surface of said imaging layer of at least about 0.2 milliwatts per square micrometer;
- and
- (III) contacting said lithographic printing plate with an aqueous alkaline developing solution to remove the exposed areas thereof and thereby form a lithographic printing surface.
A method of imaging a lithographic printing plate;
- said method comprising the steps of:
- (I) providing a lithographic printing plate comprising a support and an imaging layer that is sensitive to both ultraviolet and infrared radiation and capable of functioning in either a positive-working or negative-working manner;
- said imaging layer comprising an admixture of (1) a resole resin, (2) a novolac resin, (3) a latent Bronsted acid and (4) an infrared absorber;
- (II) imagewise exposing said imaging layer with a high-intensity laser diode emitting an infrared laser beam with an intensity at the surface of said imaging layer of at least about 0.2 milliwatts per square micrometer;
- (III) heating said lithographic printing plate to provide reduced solubility in exposed areas and increased solubility in unexposed areas;
- and
- (IV) contacting said lithographic printing plate with an aqueous alkaline developing solution to remove the unexposed areas thereof and thereby form a lithographic printing surface.
Dependencies are inferred from the claim text.