Abstract:
A method of making a relief image printing element from a photosensitive printing blank is described. The photosensitive printing blank comprises a laser ablatable mask layer disposed on at least one photocurable layer and the laser ablatable mask layer is selectively laser ablated to create an in situ mask and uncover portions of the at least one photocurable layer.
Abstract:
Photosensitive printing blank comprises a backing layer, at least one photocurable layer disposed on the backing layer, and a laser ablatable mask layer disposed on the at least one photocurable layer, wherein the laser ablatable mask layer is laser ablated to create an in situ negative in the laser ablatable mask layer, The exposing apparatus comprises: (a) a laminating apparatus for laminating an oxygen barrier layer to a top of the laser ablated mask layer; (b) a conveyor for conveying the photosensitive printing blank through the exposing apparatus; (c) a first exposing device for exposing the at least one photocurable layer to actinic radiation from the first exposing device through the laser ablated mask layer to selectively crosslink and cure portions of the at least one photocurable layer not covered by the mask layer, and (d) a second exposing device for exposing the at least one photocurable layer to actinic radiation.
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 is directed to a method and an apparatus for applying a surface treatment composition to a photosensitive printing element (15) during thermal processing. A photosensitive printing element (15) is contacted with a web of absorbent material (30) that is capable of absorbing material that is melted or softened from an imaged and exposed surface of a photosensitive printing element (15). The web of absorbent material (30) is coated with a surface treatment composition to transfer the surface treatment composition from the web of absorbent material (30) to the imaged and exposed surface of the photosensitive printing element (15). 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 (15).
Abstract:
An inkjet printer is used to apply an ink that is substantially opaque to actinic radiation in at least one wavelength region effective to cure the photosensitive printing plate to the edges and corners, of a printing plate after the plate has been trimmed (i.e., cut) to a suitable size and shape for mounting on a printing sleeve or cylinder. Use of inkjet printing allows for the cut surfaces of the plate to quickly and accurately be coated with a UV-opaque ink and prevents, or substantially eliminates, undesirable curing of cut surfaces of a photosensitive printing plate. The ink covers the photocurable surfaces exposed by the cutting process and prevents the cut surfaces of the printing plate from undesirably curing until proper exposure and development of the printing plate.
Abstract:
An apparatus for thermally processing a relief image printing element and a method of using the same are described. The printing element comprises at least one photopolymer layer and is selectively exposed to actinic radiation to crosslink portions of the at least one photopolymer layer. The apparatus comprises: (a) means for supporting the printing element; (b) heating means for melting or softening non-crosslinked portions of the at least one photopolymer layer; (c) at least one rotatable roll that is capable of bringing a blotting material into contact with the at least one photopolymer layer to remove the melted or softened non-crosslinked portions of the at least one photopolymer layer,; and (d) an element arranged adjacent to the at least one rotatable roll for removing non-crosslinked photopolymer remaining on a surface of the at least one rotatable roll after step c). The apparatus may alternatively be operated without a blotting material.
Abstract:
A method of making a relief image printing element having a relief pattern, the method comprising the steps of: a) selectively ablating the masking layer to create an overall image in the masking layer, such that the overall image comprises a sub-image, comprising a pattern of cells, in it; b) applying an oxygen barrier layer on top of the masking layer; c) exposing the printing element to actinic radiation through the oxygen barrier layer and the masking layer to selectively crosslink: and cure the at least one photocurable layer, thereby creating the relief image therein and a textured surface on the printing element; and d) developing the printing blank by removing the barrier layer and the uncured portions of the photocmable layer to reveal the relief image.
Abstract:
A photocurable printing blank comprises a backing layer having a photocurable layer disposed thereon, a barrier layer disposed on the photocurable layer, and a laser ablatable mask layer disposed on top of the barrier layer. The method includes the steps of (1 ) imaging the at least one photo curable layer by ablating the laser ablatable mask layer to create the relief pattern on the photocurable printing blank; (2) exposing the printing blank to actinic radiation through the barrier layer and mask layer to selectively crosslink portions of the photocurable layer, thereby creating the relief pattern; (3) developing the printing blank to remove the barrier layer, the laser ablated mask layer and uncured portions of the photo curable layer and reveal the relief pattern. The method can also be used with an analog platemaking process that uses a negative instead of an ablatable mask layer.
Abstract:
The present invention is directed to a method and a system for forming a relief image on a photosensitive printing element. The system comprises an enclosure housing a conveyor and a heatable roller. The photosensitive printing element is positioned on a continuous loop of the conveyor and the heatable roller is urged towards the photosensitive printing element on the conveyor. An absorbent material is conducted over the heatable roller and is used to absorb at least a portion of the liquefied or softened material from the photosensitive printing element when the heatable roller is heated. The system also comprises ventilation means operatively connected to the enclosure for treating and recycling air containing contaminants that are released into the enclosure as the portion of the photosensitive material is heated and then softens. The ventilation means typically include a particulate filter and a bed of adsorbent material. The treated air may then be returned to the enclosure.