Method for producing printing plates
A method for producing a printing plate, especially inside a printing press, wherein a printing plate with a rewritable surface is provided, and wherein to produce a permanent as well as an erasable image on the surface of the printing plate, the erasing of the surface and/or the imaging of the surface are carried out with the use of an atmospheric plasma.
1 . A method for preparing a printing plate inside a printing press, said printing plate having a rewritable surface which is imaged, said method comprising:
erasing the surface using an atmospheric plasma; and
imaging the surface.
2 . The method of claim 1 wherein the surface is imaged within thirty minutes after erasing.
3 . The method of claim 2 wherein the surface is imaged within fifteen minutes after erasing.
4 . The method of claim 1 further comprising:
preparing the surface using an atmospheric plasma, after erasing and prior to imaging.
5 . The method of claim 4 wherein a time interval of at least fifteen minutes elapses between erasing and preparing.
6 . The method of claim 1 wherein said imaging is done by a thermal transfer process, said method further comprising:
rubber coating said surface after imaging.
7 . The method of claim 3 further comprising:
rubber coating said surface after imaging; and
allowing a time interval of at least fifteen minutes between rubber coating and printing.
8 . The method of claim 7 further comprising:
fixing the surface after rubber coating; and
allowing a time interval of at least fifteen minutes between fixing and printing.
9 . The method of claim 2 further comprising allowing a maximum of thirty minutes to elapse between imaging and printing.
10 . The method of claim 2 further comprising:
rubber coating said surface after imaging; and
allowing a maximum of thirty minutes to elapse between rubber coating and printing.
11 . The method of claim 1 further comprising:
placing at least two electrodes in proximity to the surface; and
producing said atmospheric plasma with an arc between said at least two electrodes.
12 . The method of claim 1 1 further comprising conveying said atmospheric plasma toward said surface using compressed air.
13 . The method of claim 4 wherein said erasing is performed with an atmospheric plasma at a higher power density than the surface preparation.
14 . The method of claim 13 further comprising fixing the surface after imaging, said fixing being performed with an atmospheric plasma at a power density intermediate the power densities used for erasing and surface preparation.
15 . The method of claim 13 wherein said atmospheric plasma is produced by a plasma generator at a distance from said surface, said power density being varied by varying said distance.
16 . The method of claim 13 wherein the atmospheric plasma is produced by a plasma generator at a distance from said surface, said power density being varied by at least one of translating said generator relative to said surface and rotating said surface.