Inkjet-imageable lithographic printing members and methods of preparing and imaging them
Lithographic printing plates are imaged using an inkjet printer to imagewise apply a chemical or masking agent onto the plate surface. In some embodiments, the chemical causes an affinity change, thereby facilitating lithographic printing.
1 . A printing member comprising a heat-sensitive top layer having a first lithographic affinity and a layer thereunder having a second lithographic affinity opposite to the first lithographic affinity, the top layer comprising a material which, upon exposure to an imaging fluid, becomes crosslinkable by heating.
2 . The printing member of claim 1 , wherein the first lithographic affinity is hydrophilicity and the second lithographic affinity is oleophilicity.
3 . The printing member of claim 1 , wherein the first lithographic affinity is oleophilicity and the second lithographic affinity is hydrophilicity.
4 . The printing member of claim 1 , wherein the top layer comprises at least one crosslinkable moiety.
5 . The printing member of claim 4 , wherein the crosslinkable moiety is selected from the group consisting of multifunctional acrylic monomer, multifunctional acrylic oligomer, multifunctional acrylic macromer, and combinations thereof.
6 . A system for lithographic printing comprising:
(a) a printing member comprising a heat-sensitive top layer having a first lithographic affinity and a layer thereunder having a second lithographic affinity opposite to the first lithographic affinity, the top layer comprising a material which, upon exposure to an imaging fluid, becomes crosslinkable by heating, and
(b) an imaging fluid;
wherein the top layer, when subjected to heat, responds to the imaging fluid by undergoing crosslinking.
7 . The system of claim 6 , wherein the first lithographic affinity is hydrophilicity and the second lithographic affinity is oleophilicity.
8 . The system of claim 6 , wherein the first lithographic affinity is oleophilicity and the second lithographic affinity is hydrophilicity.
9 . The system of claim 6 , wherein the top layer comprises at least one crosslinkable moiety.
10 . The system of claim 9 , wherein the crosslinkable moiety is selected from the group consisting of multifunctional acrylic monomer, multifunctional acrylic oligomer, multifunctional acrylic macromer, and combinations thereof.
11 . The system of claim 6 , wherein the imaging fluid comprises a multifunctional amine.
12 . A method of imaging a lithographic printing member, the method comprising the steps of:
(a) providing a printing member comprising a heat-sensitive top layer having a first lithographic affinity and a layer thereunder having a second lithographic affinity opposite to the first lithographic affinity, the top layer comprising a material which, upon exposure to an imaging fluid, becomes crosslinkable by heating;
(b) dispensing the imaging fluid in an imagewise pattern, the imaging fluid chemically reacting with the top layer and facilitating crosslinking;
(c) subjecting the printing member to a solvent, the solvent disrupting non-image, uncrosslinked portions of the top layer; and
(d) removing the non-image portions of the top layer, thereby creating an imagewise lithographic pattern on the printing member.
13 . The method of claim 12 , wherein the solvent comprises an aqueous fluid.
14 . The method of claim 12 , wherein the first lithographic affinity is hydrophilicity and the second lithographic affinity is oleophilicity.
15 . The method of claim 12 , wherein the first lithographic affinity is oleophilicity and the second lithographic affinity is hydrophilicity.
16 . The method of claim 12 , wherein the top layer comprises at least one crosslinkable moiety.
17 . The method of claim 16 , wherein the polymerizable moiety is selected from the group consisting of multifunctional acrylic monomer, multifunctional acrylic oligomer, multifunctional acrylic macromer, and combinations thereof.
18 . The method of claim 12 , wherein the imaging fluid comprises a multifunctional amine.