Abstract: Ablation-type printing plates having improved exposure sensitivity are produced using an imaging layer—i.e., the plate layer that absorbs and ablates in response to imaging radiation—whose composition includes a large proportion of crosslinker.

Abstract: Sequentially subjecting an imaged ablation-type printing member having a silicone topmost layer to, first, a cleaning liquid that is not a solvent for silicone, followed by subjecting to a second cleaning liquid that is a silicone solvent, conditions the printing member for subsequent printing with high-solids inks.

Abstract: Embodiments of the present invention involve three-layer printing members having a central layer that is non-conductive yet abalatable at commercially realistic fluence levels. In various embodiments, the central layer is polymeric with a dispersion of nonconductive carbon black particles therein at a loading level sufficient to provide at least partial layer ablatability and water compatibility of the resulting ablation debris.

Abstract: Embodiments of the present invention involve printing members that utilize a particle-fusion imaging mechanism but avoid susceptibility to handling damage. In particular, printing plates in accordance with the invention may utilize two phases, and these may originate, during manufacture, as two particle systems. Both systems are initially dispersed in a single coating applied as a layer, or in multiple coatings applied as adjacent layers, on a substrate. The second particle system exhibits a glass-transition or thermal coalescing temperature well above room temperature and also above the temperature at which the coating is dried. The coalescing temperature of the first particle system is below the drying temperature. As a result, when the coating is dried, the first particle system coalesces and forms a binder that entrains the second particle system, which has not coalesced.

Abstract: Imaging of positive-working, IR-sensitive printing plates that use a novolac resin as the major polymer component of the imaging layer takes place with greater post-exposure latitude. In various embodiments, the imaging layer includes one or more poly(vinyl phenol) polymers or copolymers combined with one or more vinyl phenol monomers.

Abstract: Low-VOC cleaning compositions effective in removing stubborn UV inks from printing-press components include at least one non-ionic surfactant selected from the group consisting of a sorbitan ester, an ethoxylated sorbitan ester, an ethoxylated castor oil, polyethylene glycol ester and an alcohol ethoxylate; and at least one carrier comprising or consisting essentially of at least one of (i) an organic solvent miscible therewith or (ii) D-limonene. The cleaning composition has a VOC limit less than 100 g/L.

Abstract: Printing members include very thin metal imaging bilayers that combine to trap and utilize imaging radiation and, due to their minimal thicknesses, ablate easily. The bilayer may include a first (bottommost) metal layer having a high extinction coefficient in the imaging wavelength range (e.g., 600-1200 nm) and, thereover, a second metal layer having a high transmittance and low emissivity for imaging radiation.

Abstract: Printing members that include a topmost layer comprising a polymer and a silicone surfactant are durable and enable use of low imaging-power densities. The protective layer may contain an inorganic crosslinker.

Abstract: Gum solutions are formulated to develop a negative-working photopolymer imaging layer coated on an anodized aluminum substrate that has undergone a post-anodic sealing treatment with inorganic phosphate and inorganic fluoride. The gum solution contains at least one polycarboxylic acid—which may be a polymer—that beneficially desensitizes the surface after the unexposed photopolymer layer is removed.

Abstract: Affinity transitions from hydrophobic to hydrophilic states, rather than ablation mechanisms, facilitate the creation of an imagewise lithographic pattern on a printing plate. In various embodiments, a lithographic printing member comprises a topmost “imaging” layer that undergoes, in response to heat, a transition from a hydrophobic and oleophilic state to a hydrophilic state (which may or may not also be oleophilic); and a substrate disposed below the imaging layer. The affinity change in the imaging layer may be due essentially to a foaming agent therein. The foaming agent decomposes upon heating, creating a gas that foams the surface of the imaging layer. The resulting spongelike texture enables the surface to retain water, i.e., renders it hydrophilic.

Abstract: Low-VOC cleaning compositions effective in removing stubborn UV inks from printing-press components include at least one non-ionic surfactant selected from the group consisting of a sorbitan ester, an ethoxylated sorbitan ester, an ethoxylated castor oil, polyethylene glycol ester and an alcohol ethoxylate; and at least one carrier comprising or consisting essentially of at least one of (i) an organic solvent miscible therewith or (ii) D-limonene. The cleaning composition has a VOC limit less than 100 g/L.

Abstract: 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.

Abstract: Sequentially subjecting an imaged ablation-type printing member having a silicone topmost layer to, first, a cleaning liquid that is not a solvent for silicone, followed by subjecting to a second cleaning liquid that is a silicone solvent, conditions the printing member for subsequent printing with high-solids inks.

Abstract: Embodiments of the present invention involve three-layer printing members having a central layer that is non-conductive yet abalatable at commercially realistic fluence levels. In various embodiments, the central layer is polymeric with a dispersion of nonconductive carbon black particles therein at a loading level sufficient to provide at least partial layer ablatability and water compatibility of the resulting ablation debris.

Abstract: Permeability transitions rather than ablation mechanisms facilitate selective removal of the imaging layer of a lithographic plate, which allows for imaging with low-power lasers that need not impart ablation-inducing energy levels.

Abstract: Permeability transitions rather than ablation mechanisms facilitate selective removal of the imaging layer of a lithographic plate, which allows for imaging with low-power lasers that need not impart ablation-inducing energy levels.

Abstract: Embodiments of the present invention involve printing members that utilize a particle-fusion imaging mechanism but avoid susceptibility to handling damage. In particular, printing plates in accordance with the invention may utilize two phases, and these may originate, during manufacture, as two particle systems. Both systems are initially dispersed in a single coating applied as a layer, or in multiple coatings applied as adjacent layers, on a substrate. The second particle system exhibits a glass-transition or thermal coalescing temperature well above room temperature and also above the temperature at which the coating is dried. The coalescing temperature of the first particle system is below the drying temperature. As a result, when the coating is dried, the first particle system coalesces and forms a binder that entrains the second particle system, which has not coalesced.

Abstract: Embodiments of the present invention involve printing members that avoid ablation imaging mechanisms and, as a result, crosslinked topmost layers. Topmost layers as described herein exhibit good thermal stability and durability during printing, but can be cleaned (and thereby removed from unimaged areas) with water or aqueous cleaning fluids following imaging. It is found, in some embodiments, that the viability of certain topmost layers can be critically dependent on the nature of the underlying substrate, e.g., in terms of texture and/or surface volume.

Abstract: Printing members include very thin metal imaging bilayers that combine to trap and utilize imaging radiation and, due to their minimal thicknesses, ablate easily. The bilayer may include a first (bottommost) metal layer having a high extinction coefficient in the imaging wavelength range (e.g., 600-1200 nm) and, thereover, a second metal layer having a high transmittance and low emissivity for imaging radiation.

Abstract: Affinity transitions from hydrophobic to hydrophilic states, rather than ablation mechanisms, facilitate the creation of an imagewise lithographic pattern on a printing plate.