An apparatus comprises: (a) a rotatable drum configured to have a UV-curable printing plate with an ablatable layer thereon, placed thereon; (b) at least one laser beam to image the plate on the drum by ablating some of the ablatable layer according to image data to form an imaged plate; (c) an unloading area onto which a plate is movable when unloaded; and (d) a plurality of UV LEDs configured to apply UV radiation to the back of the UV-curable plate or to both the front and back of the UV-curable plate during or after the unloading of the imaged plate.

Dielectric materials with optimal mechanical properties for use in laser ablation patterning are proposed. These materials include a polymer selected from the group consisting of polyureas, polyurethane, and polyacylhydrazones. New methods to prepare suitable polyacylhydrazones are also provided. Those methods involve mild conditions and result in a soluble polymer that is stable at room temperature and can be incorporated into formulations that can be coated onto microelectronic substrates. The dielectric materials exhibit high elongation, low CTE, low cure temperature, and leave little to no debris post-ablation.

A system for preparing a photopolymer printing plate includes exposure unit comprising a plurality of UV light emitting diodes (UV LEDs), a holder comprising a UV translucent material configured to receive the printing plate, and a controller configured to activate the plurality of UV LEDs. The UV LEDs include a plurality of stationary back UV LEDs configured to emit UV radiation toward the non-printing back side of the printing plate through the holder with the printing plate disposed in a stationary position on the holder, the plurality of stationary back UV LED sources together defining at least one back array having a collective irradiation field covering an area at least coextensive with the lateral length and lateral width of the plate.

Negative-working, IR-sensitive dry printing plates utilize an oleophobic topmost layer, a nitrocellulose-based imaging layer ablatable by laser discharge, and a grained metal substrate with no heat-insulating layer intervening between the imaging layer and the substrate.

A lithographic printing plate precursor is disclosed which comprises a support, a photopolymerizable image recording layer and an overcoat which comprises a low-molecular radical inhibitor. After image-wise exposure, the plate is heated whereby the radical inhibitor diffuses from the overcoat to the image recording layer, resulting in an increase of the daylight stability of the exposed and heated precursor. Such plate is especially suitable for on-press processing.

Negative-working, IR-sensitive dry printing plates utilize an oleophobic topmost layer, a nitrocellulose-based imaging layer ablatable by laser discharge, and a grained metal substrate with no heat-insulating layer intervening between the imaging layer and the substrate.

Dry, ablation-type, nitrocellulose-containing lithographic printing members include dual adjacent imaging layers, both including an absorber and at least one containing a binder (which may include or consist essentially of a melamine resin). The absorber of the nitrocellulose-containing layer is a pigment and this layer contains no absorbing dye, while the absorber of the other imaging layer includes or consists essentially of a dye.

A mask element for flexographic printing is provided. The mask element can be used for preparing a mask that has a mask image. The mask element can include: a transparent polymeric carrier sheet; a base layer on the transparent polymeric carrier sheet, wherein the base layer comprises lecithin in a polymer binder; and an imaging layer on the base layer, wherein the imaging layer includes a non-silver halide thermally-ablatable material comprising an ablatable polymeric binder and a colorant (e.g., carbon black), and optionally an infrared (IR) dye. In some aspects, the mask element further includes a transparent overcoat layer on the imaging layer. The mask can include: imaged regions in the imaging layer and non-imaged regions in the imaging layer.

In ablation-type printing plates involving silicone acrylate top layers, curing at high oxygen levels not only substantially reduces or eliminates toning, but does not adversely affect plate durability or printing performance.

A system for preparing a photopolymer printing plate includes exposure unit with a plurality of UV sources, a holder comprising a UV translucent material configured to receive the printing plate, and a controller configured to activate the plurality of UV sources. The UV sources include at least one back array of stationary back UV sources configured to emit UV radiation toward the non-printing back side of the printing plate through the holder and at least one front array of front UV sources configured to emit UV radiation toward the printing front side of the printing plate with the printing plate disposed in a stationary position on the holder. The back array defines a collective irradiation field covering an area at least coextensive with the lateral length and width of the plate. At least one of the front array, back array, or both, include light emitting diodes (UV LEDs).