Presstek, Inc.

Mark Andy, Inc.

Sonia Rondon

Kevin Ray

Susan J Lanphear

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.

Lithographic imaging and printing without defects of electrostatic origin

A recording medium comprises an oleophilic substrate and, thereover, a topmost oleophobic layer comprising a cured polymeric silicone matrix that consists essentially of the addition-cure reaction product of a vinyl-functional polydialkylsiloxane and a silane cross-linking agent. The vinyl-functional polydialkylsiloxane has a molecular weight ranging from 30,000 to 75,000 or 110,000 to 130,000. If the molecular weight of the vinyl-functional polydialkylsiloxane is within the range of 30,000 to 75,000, the molar ratio of silane groups to vinyl groups is within the range of about 11:1 to about 25:1; and if the molecular weight of the vinyl-functional polydialkylsiloxane is within the range of 110,000 to 130,000, the molar ratio of silane groups to vinyl groups is from about 5:1 to about 27:1. The recording medium may be used as a lithographic printing plate.

Recording media and related methods

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.

Ablation-type lithographic imaging with silicone acrylate layers

Ablation-type printing plates having improved exposure sensitivity are produced using a thin imaging layer&#x2014;i.e., the plate layer that absorbs and ablates in response to imaging radiation&#x2014;whose composition includes a large proportion of radiation absorber.

Ablation-type lithographic printing members having improved exposure sensitivity and related methods

Ablation-type printing plates having increased shelf-life are produced using a melamine resin free of water prior to use. A representative production sequence includes providing a substrate having an oleophilic surface; coating, over the substrate, an oleophilic resin composition having (A) a resin phase consisting essentially of a melamine resin substantially free of water and a resole resin, the resole resin being present in an amount ranging from 0% to 28% by weight of dry film, (B) a near-IR absorber dispersed within the resin phase, and (C) a sulfonic acid catalyst dispersed within the resin phase and being present in an amount ranging from 0.7% to 1.6% by weight of dry film; curing the resin composition to produce a dry film; following resin curing, coating an oleophobic polymer composition over the cured resin composition; and curing the oleophobic polymer composition.

Ablation-type lithographic printing members having improved shelf life and related methods

Ablation-type printing plates having improved exposure sensitivity are produced using an imaging layer&#x2014;i.e., the plate layer that absorbs and ablates in response to imaging radiation&#x2014;whose composition includes a large proportion of crosslinker.

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.

Ablation-type lithographic imaging with enhanced debris removal

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.

Press cleaning with low-VOC solvent compositions

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.

Lithographic imaging with printing members having metal imaging bilayers

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.

Lithographic imaging with printing members having hydrophilic, surfactant-containing top layers

Printing members that include a plasma polymer layer exhibit enhanced tolerance for high imaging-power densities. The plasma polymer layer may contain or be adjacent to an oleophilic metal such as copper.

Lithographic printing with printing members including an oleophilic metal and plasma polymer layers

A plasma polymer layer facilitates selective removal of the imaging layer of a lithographic printing member, which allows for imaging with low-power lasers. The printing member can be used on press immediately after being imaged without the need for a post-imaging processing step.

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Nashua, NH, United States of America

Sonia Rondon