Sustainable lithographic printing plate
View Patent ↗A method of preparing a lithographic printing plate includes the steps printing a liquid on a lithographic support to form a printing area which corresponds to a raster image, wherein the raster image includes a section which has a tone-value from 90% to 100%, and the jetted liquid droplets for this section, on a corresponding part from the printing area on the lithographic support, are contactless with each other.
1. A method of preparing a lithographic printing plate comprising the steps of:
jetting liquid droplets onto a lithographic support to define a printing area that corresponds to a raster image; and
curing the jetted liquid droplets on the lithographic support to define a plurality of cured drops as the printing area; wherein
the raster image includes a section having a tone-value from 90% to 100%;
after the step of curing, the jetted liquid droplets in a portion of the printing area that corresponds to the section having the tone-value from 90% to 100% do not contact each other at a top of the jetted liquid droplets; and
when the section of the raster image has a tone-value of 100%, the portion of the printing area has a tone-value of no more than 98%.
2. The method of preparing a lithographic printing plate according to claim 1 , wherein a static contact angle of the jetted liquid droplets on the lithographic support is from 50 degrees to 110 degrees.
3. The method of preparing a lithographic printing plate according to claim 1 , wherein a maximum thickness of the printing area, after the step of curing, is between 4.0 μm and 50.0 μm.
4. The method of preparing a lithographic printing plate according to claim 1 , wherein the liquid is a UV curable inkjet liquid, and the step of curing includes UV bulb curing or UV LED curing.
5. The method of preparing a lithographic printing plate according to claim 1 , wherein the step of jetting the liquid droplets onto the lithographic support is performed by a single pass inkjet method.
6. The method of preparing a lithographic printing plate according to claim 1 , wherein the lithographic support is a grained and anodized aluminum support.
7. The method of preparing a lithographic printing plate according to claim 6 , wherein a static contact angle of the jetted liquid droplets on the lithographic support is from 50 degrees to 110 degrees.
8. The method of preparing a lithographic printing plate according to claim 7 , wherein a maximum thickness of the printing area, after the step of curing, is between 4.0 μm and 50.0 μm.
9. The method of preparing a lithographic printing plate according to claim 8 , wherein the liquid is a UV curable inkjet liquid, and the step of curing includes UV bulb curing or UV LED curing.
10. The method of preparing a lithographic printing plate according to claim 9 , wherein the UV curable inkjet liquid is jetted with a jetting viscosity from 25 mPa·s to 100 mPa·s.
11. The method of preparing a lithographic printing plate according to claim 6 , wherein the raster image corresponds to a color separation; and
a chroma difference, defined in CIELab, between a color of the color separation and a color of the cured jetted liquid droplets is smaller than 10.
12. A lithographic printing plate comprising:
a lithographic support; and
an image-wise distribution of cured ink accepting drops on the lithographic support that represent a raster image; wherein
a portion of the image-wise distribution of ink accepting drops corresponds to a section of the raster image having a tone-value from 90% to 100%;
the cured ink accepting drops do not contact each other; and
each of the cured ink accepting drops has a height, corresponding to a maximum thickness of the cured ink accepting drop, between 4.0 μm and 50.0 μm.
13. The lithographic printing plate according to claim 12 , wherein the cured ink accepting drops include crosslinked monomers and/or crosslinked oligomers.
14. The lithographic printing plate according to claim 12 , wherein the lithographic support is a grained and anodized aluminum support.
15. The lithographic printing plate according to claim 14 , wherein the cured ink accepting drops include crosslinked monomers and/or crosslinked oligomers.
16. The lithographic printing plate according to claim 15 , wherein the raster image corresponds to a color separation; and
a chroma difference, defined in CIELab, between a color of the color separation and a color of the cured jetted liquid droplets is smaller than 10.