A method includes (i) preparing a printing original plate sheet having an uncured photosensitive resin layer on a surface thereof, wherein compressive strength of the uncured photosensitive resin layer at 25 C. is 1.0 to 3.0 kgf/cm.sup.2; (ii) mounting the printing original plate sheet around a cylindrical support in such a manner that a starting terminal of the mounting and an ending terminal of the mounting are overlapped; and (iii) applying pressure to the overlapped area of the starting terminal of the mounting and the ending terminal of the mounting at a temperature range of 10 to 40 C. so as to pressure-bond the overlapped area. The method may further include, after the step (iii), a step (iv) for photo-curing the uncured photosensitive resin layer and may further comprise, after the step (iv), a step (v) for grinding, abrading and/or machining the overlapped area.

A method of flood exposing a photocurable printing blank to actinic radiation from a UV LED light source, wherein a high intensity UV LED light source is modulated to a lower intensity. The method includes the steps of: (a) positioning the photocurable printing blank in an exposure unit, wherein the exposure unit comprises one or more high intensity UV LED light sources; (b) modulating intensity of the one or more high intensity UV LED light sources to a lower intensity; and (c) flood exposing the photocurable printing blank through the photographic negative or the digitally imaged mask layer to actinic radiation from the one or more modulated UV LED light sources.

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 photo curable layer. Diffusion of oxygen 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 dots and a dot shape that provide optimal print performance on various substrates, including corrugated board.

An apparatus for thermally processing a relief image printing element and a method of using the same. The relief image 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, while portions of the at least one photopolymer layer are not exposed to actinic radiation, and are not crosslinked. The apparatus comprises: a) a means for supporting the relief image 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) a rotatable cleaning roll 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).

An apparatus for aligning an edge, such as a leading edge of a plate, in particular a printing plate or a printing plate precursor. The apparatus includes a support configured for supporting the plate on a support surface, and to be located upstream of a treatment station. At least two movable elements are arranged to be moved by an edge, such as a leading edge, of the plate. The at least two movable elements include a first and a second movable element; a detection means configured to detect a first and second measure representative for a first and second position of the first and second movable element, respectively, at least one controllable component configured to perform an action on the plate, and a control means configured to control the at least one controllable component based on the first and second measure.

A system for moving a flexible plate, in particular a printing plate or a printing plate precursor, over a support surface in the direction of a treatment station, such as a washer station. The system includes a support configured for supporting the plate on a support surface thereof, and intended to be located upstream of the treatment station. A movement means includes a plate engagement means configured to contact the plate in such a way that the plate is engaged by adhesion or by friction or a combination thereof, in a movement mode, and that the plate can be slid over the support surface by controlling the movement means in the movement mode. A control means is configured to control the movement means such that the plate is slid over the support in the direction of the treatment station.