Abstract:
A method of making a relief image printing element from a liquid photopolymer composition is described. The method includes the steps of (1) casting a liquid photopolymer layer onto a cover sheet and at least substantially simultaneously placing a backing sheet onto the liquid photopolymer layer; (2) preliminarily exposing the liquid photopolymer layer to actinic radiation to create at least one island of solid photopolymer in the liquid photopolymer layer where it is desirable to laser engrave a relief image; (3) reclaiming uncured liquid photopolymer from the relief image printing element; (4) processing the at least one island of solid photopolymer to remove uncured liquid photopolymer; (5) exposing the at least one island of solid photopolymer to actinic radiation to fully cure the islands of solid photopolymer; and (6) laser engraving the at least one island of solid photopolymer to produce the relief image therein.
Abstract:
A clean running flexographic relief image printing element and a method of making the same is described. The relief image printing element comprises (a) a backing layer; (b) a floor layer disposed on the backing layer and comprising a photopolymer containing a silicone monomer or silicone oil, wherein the cured floor layer has a surface energy of between about 18 to about 25 dynes/cm; (c) a cap layer disposed on the floor layer and comprising a photocurable composition that is capable of being imagewise exposed to actinic radiation to create a relief image therein, wherein the cap layer has a surface energy of between about 30 and about 40 dynes/cm; and (d) a removable cover sheet. The differential of surface energies between the floor layer and the cap layer increases how clean the plate will print over time.
Abstract:
A method of controlling surface roughness of a flexographic printing element during thermal processing is provided. The relief image printing element of the invention comprises a photopolymer that has been selectively imagewise exposed to actinic radiation to selectively crosslink and cure portions of the photopolymer. The method generally comprises removing uncrosslinked and uncured portions of the photopolymer by heating the photopolymer and contacting it with a blotting material. The photopolymer is then contacted under heat and pressure with a smooth material, e.g., a laminated polymeric film, which smooth material is removed resulting in a relief image printing element with reduced surface roughness.
Abstract:
Apparatus for thermally developing a flexographic printing element to reveal a relief image on the surface and a method to develop a flexographic printing element. The method includes softening or melting a crosslinked photopolymer on the imaged and exposed surface of the flexographic printing element. The apparatus includes a roll that contacts the imaged surface of the flexographic printing element and moves over 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. The non-crosslinked photopolymer is softened or melted using a heater adjacent to the imaged surface of the flexographic printing element, or by heating the one roll that contacts the surface of the printing element. Optionally the apparatus a device to cure the imaged surface of the flexographic printing element prior to thermal development.
Abstract:
A means for removably attaching a printing plate to a printing cylinder using an intermediate sheet of photopolymer. The tack of the photopolymer is used to attach itself to the printing cylinder and to attach the printing plate to it. Microspheres are incorporated into the photopolymer sheet to provide a cushioning effect when in use on the printing press.
Abstract:
The present invention is directed to a method of selectively pre-exposing a photosensitive printing element prior to imagewise exposure in order to remove oxygen from the photosensitive layer prior to imagewise exposure The invention is usable in a computer-to-plate process to produce flexographic relief image printing elements
Abstract:
L'invention concerne un dispositif de gaufrage, tel qu'un cylindre ou manchon du type comportant sur sa surface périphérique externe un motif de gaufrage en relief et en creux, destiné à être reproduit sur une substance plane et déf ormable. Le dispositif est caractérisé en ce que le cylindre ou manchon (2) porte un revêtement de photopolymère (6) dont la surface extérieure présente le motif de gaufrage à relief (4). L'invention est utilisable pour le gaufrage sur des substances planes et déf ormables.
Abstract:
A method and a system for dynamic imaging, UV-exposure and thermal development of relief image printing elements, including printing plates and printing sleeves. The imaging step is accomplished using ink jet printing to create an in situ mask layer on a layer of photocurable material followed by exposing the photocurable layer to actinic radiation through the in situ mask. Thereafter, the printing element is developed in a thermal developing system to create the desired relief image in the surface. If desired, the improved system may also include means for post-exposing/detacking the printing element.
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:
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.