Method and apparatus for rapidly heating printing plates
View Patent ↗Rapid heating of a lithographic printing plate is achieved by feeding the printing plate along a substantially curved path that is adjacent to one or more curved pads of an air bearing that is pressurized with heated air. The one or more curved pads are constructed such that the substantially curved path is curved with an axis of curvature substantially perpendicular to the feed direction of the printing plate. The plate is additionally elastically bent to follow and conform to the substantially curved path. The substantially curved path minimizes printing plate distortion during heating, and thus prevents the plate from being damaged from contact with any of the one or more curved pads. The one or more curved pads are also arranged to allow for exceptionally good heat transfer characteristics and thus more effective plate heating.
1. A method for heating a planar printing plate, the method comprising:
pressurizing and heating a flow of air,
moving the planar printing plate along a substantially curved path,
wherein the substantially curved path is adjacent to a first curved surface, the first curved surface comprising:
a plurality of openings, the plurality of openings being operable to convey at least a part of the flow of air,
bending the planar printing plate as it is moved along the substantially curved path, and
conveying the at least a part of the flow of air through the first curved surface wherein at least a portion of the planar printing plate along the substantially curved path comprises a photopolymer or thermal photosensitive coating, and wherein the coating is
heated by the at least a part of the flow of air, and
is prevented from contacting the first curved surface by the at least a part of the flow of air,
wherein the conveying the at least a part of the flow of air commences less than 5 minutes before the planar printing plate is moved along the substantially curved path.
2. The method of claim 1 wherein the substantially curved path is adjacent to a second curved surface, the second curved surface comprising a plurality of openings operable to convey at least an additional part of the flow of air, and wherein the method further comprises:
conveying the at least an additional part of the flow of air through the second curved surface, wherein the at least a portion of the planar printing plate along the substantially curved path and wherein said photopolymer or thermal photosensitive coating is
heated by the at least an additional part of the flow of air, and
is prevented from contacting the second curved surface by the at least the additional part of the flow of air.
3. The method of claim 2 comprising arranging the first curved surface and the second curve surface, wherein a gap is formed there between and the substantially curved path is established within the gap.
4. The method of claim 3 further comprising arranging the first curved surface and the second curved surface, wherein the gap is substantially uniform along the substantially curved path.
5. The method of claim 3 further comprising arranging the first curved surface and the second curved surface, wherein the gap is smaller when the planar printing plate is not moved along the substantially curved path.
6. The method of claim 3 wherein the planar printing plate includes a thickness, the method further comprising arranging the first curved surface and the second curved surface, wherein the gap is not greater than three times the thickness of the planar printing plate.
7. The method of claim 3 further comprising arranging the first curved surface and the second curved surface, wherein the gap is within a range of from about 0.75 mm to about 1.5 mm.
8. The method of claim 2 wherein the bending the planar printing plate comprises bending the at least a portion of the planar printing plate along the substantially curved path with at least one of:
the at least a part of the flow of air, and
the at least an additional part of the flow of air.
9. The method of claim 2 further comprising arranging the first curved surface and the second curved surface, wherein the substantially curved path has at least one radius of curvature and, wherein the bending the planar printing plate comprises bending the at least a portion of the planar printing plate along the substantially curved path with a radius of curvature that is substantially equal to the at least one radius of curvature.
10. The method of claim 9 further comprising arranging the first curved surface and the second curved surface, wherein the at least one radius of curvature is from about 200 mm to about 1000 mm.
11. The method of claim 1 wherein the planar print plate is additionally moved along a feed direction, and the substantially curved path has at least one axis of curvature that is substantially perpendicular to the feed direction.
12. The method of claim 1 wherein the bending the planar printing plate comprises elastically bending the planar printing plate.
13. The method of claim 1 wherein the method further comprises supporting the at least a portion of the planar printing plate along the substantially curved path with a support means, wherein the coating is prevented from contacting the support means.
14. The method of claim 1 wherein the bending the planar printing plate comprises applying a bending moment to the planar printing plate.
15. The method of claim 1 further comprising at least one of:
re-circulating and reusing the flow of air,
filtering the flow of air, and
conveying the flow of air through a catalytic converter.
16. The method of claim 1 wherein the flow of air is pressurized to from about 50 mbars to about 500 mbars.
17. The method of claim 1 wherein the flow of air is heated to a temperature of from about 100 to about 250° C.
18. A method for heating a planar printing plate, the method comprising:
pressurizing and heating a flow of air,
moving the planar printing plate along a substantially curved path,
wherein the substantially curved path is adjacent to a first curved surface, the first curved surface comprising:
a plurality of openings, the plurality of openings being operable to convey at least a part of the flow of air,
bending the planar printing plate as it is moved along the substantially curved path, and
conveying the at least a part of the flow of air through the first curved surface wherein at least a portion of the planar printing plate along the substantially curved path comprises a photopolymer or thermal photosensitive coating, and wherein the coating is
heated by the at least a part of the flow of air, and
is prevented from contacting the first curved surface by the at least a part of the flow of air,
wherein the substantially curved path is adjacent to a second curved surface, the second curved surface comprising a plurality of openings operable to convey at least an additional part of the flow of air, and wherein the method further comprises:
conveying the at least an additional part of the flow of air through the second curved surface, wherein the at least a portion of the planar printing plate along the substantially curved path and wherein said photopolymer or thermal photosensitive coating is
heated by the at least an additional part of the flow of air, and
is prevented from contacting the second curved surface by the at least the additional part of the flow of air,
further comprising arranging the first curved surface and the second curve surface, wherein a gap is formed there between and the substantially curved path is established within the gap, and
further comprising arranging the first curved surface and the second curved surface, wherein the gap is smaller when the planar printing plate is not moved along the substantially curved path.
19. A method for heating a planar printing plate, the method comprising:
pressurizing and heating a flow of air,
moving the planar printing plate along a substantially curved path,
wherein the substantially curved path is adjacent to a first curved surface, the first curved surface comprising:
a plurality of openings, the plurality of openings being operable to convey at least a part of the flow of air,
bending the planar printing plate as it is moved along the substantially curved path, and
conveying the at least a part of the flow of air through the first curved surface wherein at least a portion of the planar printing plate along the substantially curved path comprises a photopolymer or thermal photosensitive coating, and wherein the coating is
heated by the at least a part of the flow of air, and
is prevented from contacting the first curved surface by the at least a part of the flow of air,
wherein the flow of air comprises an airflow and the method further comprises reducing the airflow before the planar printing plate is moved along the substantially curved path.