Abstract:
A method of making a relief image printing element from a photosensitive printing blank is provided. A photosensitive printing blank with a laser ablatable layer disposed on at least one photocurable layer is ablated with a laser to create an in situ mask. The printing blank is then exposed to at least one source of actinic radiation through the in situ mask to selectively cross link and cure portions of the photocurable layer. Diffusion of air into the at least one photocurable layer is limited during the exposing step and preferably at least one of the type, power and incident angle of illumination of the at least one source of actinic radiation is altered during the exposure step. The resulting relief image comprises a plurality of dots and a dot shape of the plurality of dots that provide optimal print performance on various substrates, including corrugated board.
Abstract:
The present invention relates to an improved compressible flexographic printing plate that uses a compressible layer comprising a polyurethane (meth)acrylate resin and microspheres. The process of the invention produces a chemically fused printing plate that eliminates the need for an adhesive to secure the compressible layer to the back of the printing plate.
Abstract:
An improved flexo processor and a method of using the improved flexo processor to increase the flexibility of both the type and the size of the flexographic printing element that may be processed. The novel thermal plate processor system is capable of processing both flat and round photosensitive printing elements with only minimal changes to the system. The thermal plate processor system may also include means for exposure and post-exposure/detack in the same system.
Abstract:
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.
Abstract:
The present invention relates to an improved slip film composition for use in manufacturing flexographic printing plates. The improved slip film composition of the invention comprises one or more solvents, one or more polymeric binders, a layered silicate, and optionally, a surfactant. The use of the layered silicate as a filler in the slip film composition produces an slip film composition with improved release properties and improved imaging. The slip film of the invention can be used with flexographic printing plates that are solvent developed or thermally developed.
Abstract:
The present invention pertains to a process and an apparatus for treating a photosensitive element to form a relief structure suitable for flexographic printing plate. The apparatus comprises an enclosure, a conveyor, a heatable roller with absorbent material conducted over it, and a roller that can significantly smooth or uniformly roughen the relief structure of the flexographic printing plate. Previously selectively cured photosensitive elements are developed by means of the heatable roller by blotting with the absorbent material, and the resulting relief structure is made uniform by way of a smoothing or roughening roller. The flexographic plates produced by the method and apparatus are especially suited to processes that require substantially smoothed or uniformly roughened printing plate surfaces, which are capable of producing better quality printing.
Abstract:
The present invention relates to an improved compressible flexographic printing plate that uses a compressible layer comprising a polyurethane (meth)acrylate resin and microspheres. The process of the invention produces a chemically fused printing plate that eliminates the need for an adhesive to secure the compressible layer to the back of the printing plate.
Abstract:
The present invention is directed to a method and an apparatus for applying a surface treatment composition to a photosensitive printing element during thermal processing. A photosensitive printing element is contacted with a web of absorbent material that is capable of absorbing material that is melted or softened from an imaged and exposed surface of a photosensitive printing element. The web of absorbent material is coated with a surface treatment composition to transfer the surface treatment composition from the web of absorbent material to the imaged and exposed surface of the photosensitive printing element. Applying the surface treatment composition during thermal processing provides for more complete and more uniform coverage of the surface treatment composition on the photosensitive printing element.
Abstract:
An improved method of manufacturing a photosensitive printing element that minimizes relief variation and improves image fidelity. The method involves a step of pre-curing the first (floor layer) of photocurable material prior to depositing an additional layer or layers of photocurable material that may be imaged and developed to produce a desired relief image on the surface of the photosensitive printing element. The photosensitive printing element is then thermally developed by contacting the photosensitive printing element with at least one roll that is 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. Non-crosslinked photopolymer on the imaged and exposed surface of the flexographic printing element can be softened or melted by positioning a heater 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.
Abstract:
A method of producing a relief image from a liquid photopolymerizable resin, said method comprising the steps of a) placing a coverfilm onto an exposure glass; b) casting a liquid photopolymerizable resin layer onto the coverfilm; c) laminating a substrate to a backside of the liquid photopolymerizable resin layer as the liquid photopolymerizable resin layer is being cast onto the coverfilm; d) placing an image or film negative on top of the substrate; and e) exposing the liquid photopolymerizable resin layer through the image or film negative from the backside of the liquid photopolymerizable resin layer to selectively crosslink and cure the photopolymerizable resin layer and form a cured relief image, wherein said depth of the cured relief image is less than the height of the cast liquid photopolymerizable resin.