Carrier sheet for a photosensitive printing element
View Patent ↗An improved apparatus for thermally developing a flexographic printing element to reveal a relief image on the surface and a method of using the apparatus to develop a flexographic printing element. The apparatus typically comprises means for softening or melting a crosslinked photopolymer on the imaged and exposed surface of the flexographic printing element; at least one roll that is contactable with the imaged surface of the flexographic printing element and capable of moving over at least a portion of the imaged surface of the flexographic printing element to remove the softened or melted non-crosslinked photopolymer on the imaged and exposed surface of the flexographic printing element; and means for maintaining contact between the at least one roll and the imaged and exposed surface of the flexographic printing element. A layer of resilient compressible material is positioned between the flexographic printing element and a supporting conveying means. The means for softening or melting non-crosslinked photopolymer on the imaged and exposed surface of the flexographic printing element comprise a heater positioned adjacent to the imaged surface of the flexographic printing element and/or heating the at least one roll that contactable with the imaged surface of the flexographic printing element. The apparatus may also contain an exposure device to crosslink and cure the imaged surface of the flexographic printing element prior to thermal development.
1. A system for forming a relief image on a photosensitive printing element, wherein the photosensitive printing element comprises a flexible substrate and at least one layer of photosensitive material deposited on the flexible substrate, the system comprising:
a frame;
a means for supporting and conveying the photosensitive printing element, wherein the photosensitive printing element is positioned on the means for supporting and conveying with a layer of resilient compressible material removably positioned between the photosensitive printing element and the means for supporting and conveying;
a heatable roller capable of being urged towards the photosensitive printing element positioned on the means for supporting and conveying, wherein an absorbent material is conducted over at least a portion of an outer surface of the heatable roller, and wherein the absorbent material is capable of absorbing material that is liquefied or softened from the photosensitive printing element when the heatable roller is heated and rotates and the absorbent material contacts at least a portion of the photosensitive printing element; and
means for causing the photosensitive material and the absorbent printing element to come into contact at a point between the means for supporting and conveying and the heatable roller such that at least a portion of the liquefied or softened material is absorbed by the absorbent material.
2. The system according to claim 1 , further comprising delivery means for supplying the absorbent material to at least the portion of the outer surface of the heatable roller.
3. The system according to claim 1 , further comprising heating means for applying heat to the photosensitive printing element on the means for supporting and conveying, wherein said heating means are positioned adjacent to a point where the absorbent material contacts the photosensitive printing element on the means for supporting and conveying.
4. The system according to claim 1 wherein the means for supporting and conveying is selected from the group consisting of a continuous conveyor and a rotating drum.
5. The system according to claim 1 wherein the layer of resilient compressible material has a resilience from 10 to 60 and a compressibility from 15 psi to 25 psi at 25% compression.
6. The system to claim 5 wherein the means for supporting and conveying is selected from the group consisting of a continuous conveyor and a rotating drum.
7. A method of forming a relief image on a photosensitive printing element, wherein the photosensitive printing element comprises a flexible substrate and at least one layer of photosensitive material deposited on the flexible substrate, the method comprising the steps of:
providing a frame;
positioning a photosensitive printing element on a supporting and conveying means with a layer of resilient compressible material removably positioned between the photosensitive printing element and the supporting and conveying means, said supporting and conveying means comprising a continuous loop or a rotating drum;
supplying an absorbent material to at least a portion of an outer surface of a heatable roller, said heatable roller being mounted for rotation in the frame, wherein the absorbent material is capable of absorbing material that is liquefied or softened from the photosensitive printing element when the heatable roller is heated and the absorbent material contacts at least a portion of the photosensitive printing element;
heating the heatable roller to a temperature sufficient to cause at least a portion of the photosensitive printing element to soften or liquefy when the absorbent material contacts the at least one layer photosensitive material; and
causing the photosensitive material and the absorbent printing element to come into contact at a point between the conveyor and the heatable roller such that at least a portion of the liquefied or softened material is absorbed by the absorbent material.
8. The method according to claim 7 , further comprising the step of applying heat to the photosensitive printing element on the conveyor by positioning a heater adjacent to a point where the absorbent material contacts the photosensitive printing element on the conveyor.
9. The method according to claim 7 wherein the means for supporting and conveying is selected from the group consisting of a continuous conveyor and a rotating drum.
10. The method according to claim 7 wherein the layer of resilient compressible material has a resilience from 10 to 60 and a compressibility from 15 psi to 25 psi at 25% compression.