Claims
- 1. Direct-to-plate method of lithographic printing with a reusable substrate having a hydrophilic surface comprising the steps of:(a) making a negative-working imaging layer by coating on the hydrophilic surface a solution comprising hydrophobic thermoplastic particles; (b) making a printing master having ink-accepting areas by image-wise exposing the imaging layer to heat or light; (c) applying ink and fountain solution to the printing master; (d) removing the ink-accepting areas from the printing master by supplying a cleaning liquid to the imaging layer thereby obtaining a recycled substrate, wherein the cleaning liquid comprises an aqueous emulsion of an alcohol and a cyclic compound having at least one double bond, and (e) treating the recycled substrate by supplying a refreshing liquid consisting of an aqueous solution having a pH<7.
- 2. Method according to claim 1 wherein the negative-working imaging layer comprises a hydrophilic binder.
- 3. Method according to claim 2 wherein the aqueous solution having a pH<7 comprises a compound according to formula I: wherein X is OH, O− or a polymer backbone.
- 4. Method according to claim 2 wherein during step (d) the printing master is treated by mechanical means.
- 5. Method according to claim 4 wherein the mechanical means is selected from the group consisting of a cloth, a rotating brush or by jetting water or a volatile medium.
- 6. Method according to claim 2 wherein the reusable substrate is a plate cylinder of a rotary press or a plate or sleeve mounted on a plate cylinder of a rotary press.
- 7. Method according to claim 2 wherein the solution comprising hydrophobic thermoplastic particles, the cleaning liquid, or the refreshing liquid is jetted onto the substrate.
- 8. Method according to claim 1 wherein the aqueous solution having a pH<7 comprises a compound according to formula I: wherein X is OH, O− or a polymer backbone.
- 9. Method according to claim 8 wherein the compound according to formula (I) is phosphoric acid or a phosphate salt.
- 10. Method according to claim 9 wherein during step (d) the printing master is treated by mechanical means.
- 11. Method according to claim 10 wherein the mechanical means is selected from the group consisting of a cloth, a rotating brush or by jetting water or a volatile medium.
- 12. Method according to claim 9 wherein the reusable substrate is a plate cylinder of a rotary press or a plate or sleeve mounted on a plate cylinder of a rotary press.
- 13. Method according to claim 8 wherein during step (d) the printing master is treated by mechanical means.
- 14. Method according to claim 13 wherein the mechanical means is selected from the group consisting of a cloth, a rotating brush or by jetting water or a volatile medium.
- 15. Method according to claim 8 wherein the reusable substrate is a plate cylinder of a rotary press or a plate or sleeve mounted on a plate cylinder of a rotary press.
- 16. Method according to claim 1 wherein during step (d) the printing master is treated by mechanical means.
- 17. Method according to claim 16 wherein the reusable substrate is a plate cylinder of a rotary press or a plate or sleeve mounted on a plate cylinder of a rotary press.
- 18. Method according to claim 16 wherein the mechanical means is selected from the group consisting of a cloth, a rotating brush or by jetting water or a volatile medium.
- 19. Method according to claim 1 wherein the reusable substrate is a plate cylinder of a rotary press or a plate or sleeve mounted on a plate cylinder of a rotary press.
- 20. Method according to claim 1 wherein the solution comprising hydrophobic thermoplastic particles, the cleaning liquid or the refreshing liquid is sprayed onto the substrate.
- 21. Method according to claim 20 wherein during step (d) the printing master is treated by mechanical means.
- 22. Method according to claim 21 wherein the mechanical means is selected from the group consisting of a cloth, a rotating brush or by jetting water or a volatile medium.
- 23. Method according to claim 20 wherein the reusable substrate is a plate cylinder of a rotary press or a plate or sleeve mounted on a plate cylinder of a rotary press.
- 24. Method according to claim 1 wherein the solution comprising hydrophobic thermoplastic particles, the cleaning liquid, or the refreshing liquid is jetted onto the substrate.
- 25. Method according to claim 24 wherein during step (d) the printing master is treated by mechanical means.
- 26. Method according to claim 25 wherein the mechanical means is selected from the group consisting of a cloth, a rotating brush or by jetting water or a volatile medium.
- 27. Method according to claim 24 wherein the reusable substrate is a plate cylinder of a rotary press or a plate or sleeve mounted on a plate cylinder of a rotary press.
Priority Claims (1)
Number |
Date |
Country |
Kind |
00204376 |
Dec 2000 |
EP |
|
Parent Case Info
This application claims the benefit of U.S. Provisional Patent Application No. 60/259,483, filed Jan. 3, 2001, which is incorporated by reference.
US Referenced Citations (13)
Foreign Referenced Citations (2)
Number |
Date |
Country |
0 770 495 |
May 1997 |
EP |
0 802 457 |
Oct 1997 |
EP |
Provisional Applications (1)
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Number |
Date |
Country |
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60/259483 |
Jan 2001 |
US |