Method for developing multilayer imageable elements
View Patent ↗A method for forming an image by imaging and developing a multi-layer imageable element, in which the developer is fresh developer and the developer is not reused, is disclosed. Much smaller variation in dot percentage is obtained when each imaged imageable element is developed in fresh developer than when the developer is reused to develop additional imaged imageable elements. The method is especially suited to the formation of images using stochastic screening. Either a solvent based developer or a high pH developer may be used.
1. The invention is a method for forming an image comprising the steps of:
a) thermally imaging a multi-layer imageable element and forming an imaged imageable element comprising imaged and complementary unimaged regions;
in which:
the imageable element comprises a substrate, an underlayer over the substrate, and a top layer over the underlayer;
the element comprises a photothermal conversion material;
the top layer is substantially free of the photothermal conversion material;
the top layer is ink receptive;
before thermal imaging, the top layer is not removable by an alkaline developer;
after thermal imaging, the imaged regions are removable by the developer; and
the underlayer is removable by the developer; and
b) developing the imaged imageable element with the developer and removing the imaged regions without substantially affecting the unimaged regions;
in which:
the developer is fresh developer; and
the developer is not reused.
2. The method of claim 1 in which the developer is a solvent based developer, and the developer has a pH below about 10.5.
3. The method of claim 1 in which the developer is a high pH developer.
4. The method of claim 1 in which about 0.5 L to 4.0 L of developer is used per m 2 of imaged imageable element.
5. The method of claim 4 in which imaging is carried out using stochastic screening.
6. The method of claim 1 in which the top layer comprises a novolac resin and a dissolution inhibitor.
7. The method of claim 6 in which the underlayer comprises a copolymer of N-phenylmaleimide, methacrylamide, and methacrylic acid.
8. The method of claim 1 in which imaging is carried out using stochastic screening.
9. The method of claim 8 in which the top layer comprises a novolac resin and a dissolution inhibitor.
10. The method of claim 9 in which the underlayer comprises a copolymer of N-phenylmaleimide, methacrylamide, and methacrylic acid.
11. The method of claim 10 in which the developer is a solvent based developer, and the developer has a pH below about 10.5.
12. The method of claim 11 in which about 0.5 L to 4.0 L of developer is used per m 2 of imaged imageable element.
13. The method of claim 10 in which the developer is a high pH developer.
14. The method of claim 13 in which about 0.5 L to 4.0 L of developer is used per m 2 of imaged imageable element.