Claims
- 1. A method of forming a desired positive image on a lithographic printing plate comprising a hydrophilic substrate with an oleophilic coating thereon wherein said coating is soluble in a selected solvent, said method comprising the application in a desired pattern of said selected solvent to said coating by ink jet thereby dissolving away said coating in said desired pattern and thus exposing said hydrophilic substrate and forming a residual oleophilic coating in the form of the desired positive image on the hydrophilic substrate.
- 2. A method as recited in claim 1 and further including the step of hardening said residual oleophilic coating.
- 3. A method as recited in claim 1 wherein said coating is selected from the group consisting of novalac resins, resole resins, acrylate resins, diazo resins and photopolymers.
- 4. A method as recited in claim 1 wherein said coating has a composition which may be insolubilized by actinic radiation and further including the step of post treating with actinic radiation to insolubilize said residual oleophilic coating.
- 5. A method as recited in claim 4 wherein said coating comprises a photopolymer or a diazo resin or mixtures thereof.
- 6. A method as recited in claim 1 wherein said coating has a composition which may be hardened by heating and further including the step of post treating by heating to harden said residual oleophilic coating.
- 7. A method as recited in claim 6 wherein said coating comprises a phenolic resin.
- 8. A method as recited in claim 1 wherein said solvent is an aqueous solution.
- 9. A method as recited in claim 8 wherein said aqueous solution is a solution of sodium metasilicate.
- 10. A method as recited in claim 8 wherein said aqueous solution is an aqueous alkaline solution.
- 11. A method as recited in claim 1 wherein said solvent comprises an organic solvent.
- 12. A method as recited in claim 8 wherein said aqueous solution contains an organic solvent.
- 13. A method as recited in claim 12 wherein said aqueous solution is an aqueous alkaline solution.
- 14. A method as recited in claim 13 wherein said aqueous solution comprises a solution of sodium metasilicate and said organic solvent is benzyl alcohol.
- 15. A method as recited in claim 11 wherein said organic solvent is selected from the group consisting of ketones, alcohols, ethers and ether linked alcohols and acetates.
- 16. A method as recited in claim 15 wherein said solvent is selected from the group consisting of methyl ethyl ketone, cyclohexanone, acetone, glycol ethers, dioxane, benzyl alcohol, 1-methoxy-2-propanol and 3-methoxyethyl acetate.
Parent Case Info
[0001] This application is a continuation-in-part of application Ser. No. 10/213,831 filed Aug. 6, 2002.
Continuation in Parts (1)
|
Number |
Date |
Country |
Parent |
10213831 |
Aug 2002 |
US |
Child |
10324918 |
Dec 2002 |
US |