Lithographic printing plate precursor
AssigneeAGFA Offset BV
InventorsThomas Billiet, Eva Vermeiren
Life of this patent
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Abstract
A lithographic printing plate precursor is disclosed including a support and a coating comprising (i) a photopolymerisable layer including a polymerisable compound and a photoinitiator, and a toplayer provided above the photopolymerisable layer; characterized in that the toplayer has a thickness comprised between 0.1 g/m2 and 1.75 g/m2 and includes an infrared absorbing compound which includes a thermocleavable group which transforms into a group which is a stronger electrondonor upon exposure to heat and/or IR radiation, and is capable of forming a printout image upon exposure to heat and/or IR radiation.
Claims15
A lithographic printing plate precursor comprising a support and a coating comprising (i) a photopolymerisable layer comprising a polymerisable compound and a photoinitiator, and (ii) a toplayer above the photopolymerisable layer;
- wherein the toplayer has a thickness between 0.1 g/m2 and 0.552 g/m2 and comprises an infrared absorbing compound comprising a thermocleavable group which, upon exposure to heat and/or IR radiation, transforms into an electron-donor group such that the infrared absorbing compound undergoes a hypsochromic shift, and the infrared absorbing compound forms a print-out image upon exposure to IR radiation between 10 mJ/cm2 and 150 mJ/cm2.
A method for making a printing plate precursor comprising the steps of:
- coating a support with:
- (i) a photopolymerisable layer comprising a polymerisable compound and a photoinitiator, and
- (ii) a toplayer above the photopolymerisable layer, wherein the toplayer has a thickness between 0.1 g/m2 and 0.552 g/m2 and comprises an infrared absorbing compound comprising a thermocleavable group which, upon exposure to heat and/or IR radiation, transforms into an electron-donor group such that the infrared absorbing compound undergoes a hypsochromic shift, and the infrared absorbing compound forms a print-out image upon exposure to IR radiation between 10 mJ/cm2 and 150 mJ/cm2, to provide a precursor, and
- drying the precursor.
A method for making a printing plate including the steps of:
- image-wise exposing a lithographic printing plate precursor to heat and/or IR radiation to form a lithographic image comprising image areas and non-image areas and to induce a colour change in the image areas;
- and
- developing the exposed precursor,
- wherein the lithographic printing plate precursor comprises a support and a coating comprising (i) a photopolymerisable layer comprising a polymerisable compound and a photoinitiator, and (ii) a toplayer above the photopolymerisable layer, wherein the toplayer has a thickness between 0.1 g/m2 and 0.552 g/m2 and comprises an infrared absorbing compound comprising a thermocleavable group which, upon exposure to heat and/or IR radiation, transforms into an electron-donor group such that the infrared absorbing compound undergoes a hypsochromic shift, and the infrared absorbing compound forms a print-out image upon exposure to IR radiation between 10 mJ/cm2 and 150 mJ/cm2.
Dependencies are inferred from the claim text.