Abstract: A method for forming a printing plate from a printing plate precursor having a radiation-sensitive layer, sensitive to radiation in a first frequency spectrum such as the far or near infrared, and to radiation in a second frequency spectrum other than the first frequency spectrum such as visible or ultraviolet. The plate is exposed twice. Once to imaging radiation in the first frequency spectrum and again to radiation in the second frequency spectrum. The second frequency spectrum exposure is done only to the areas of the plate undesirably shaded during the imagewise exposure.

Abstract: A method for reducing start up blinding in no-process lithographic printing plates is disclosed. An imageable element, comprising an imageable layer over a substrate, is thermally imaged. The imageable layer comprises a thermally sensitive polymer that comprises quaternary ammonium salts of carboxylic acids. Following imaging, the surface of the imaged imageable is contacted with an aqueous solution comprising 0.05 wt % to about 5 wt % of an added organic acid having a pKa of about 1 to about 6. This reduces the amount of waste produced by the printing process by reducing the number of unusable sheets produced during the “make ready” process.

Abstract: A method for forming an image by imaging and developing a multi-layer imageable element is disclosed. When thermally imageable, multi-layer imageable elements that have been imaged using stochastic screening are developed, a much smaller variation in dot percentage throughout the developer loading cycle is observed when a smaller initial charge of developer and a higher replenishment rate than are used in a conventional developing process are used. The developer is a solvent based developer with a pH below about 10.5. The developed imageable elements are useful as lithographic printing plates.

Abstract: An imaging member, such as a negative-working printing plate or on-press cylinder, can be prepared using a hydrophilic imaging layer comprising a hydrophilic heat-sensitive polymer containing a crosslinking agent comprising ionic groups and epoxy groups. This polymer may comprise quaternary ammonium carboxylate groups which may include at least one substituted-alkylene(C1-C3)-phenyl group. The imaging member also includes an infrared radiation sensitive material to provide added sensitivity to heat that can be supplied by laser irradiation in the IR region. The heat-sensitive polymer may be “switchable” in response to heat, and provides a lithographic image without wet processing.

Abstract: A direct-to-press imaging method comprises: (a) applying an imageable coating to a printing cylinder, wherein the imageable coating comprises a composition such as a thermally switchable polymer which changes affinity for a printing fluid upon exposure to imaging radiation such as infrared radiation delivered imagewise via a laser, and the imageable coating is substantially insoluble in the printing fluid; (b) imagewise exposing the imageable coating to actinic radiation to obtain an imaged coating; (c) printing a plurality of copies of an image from the imaged coating; and (d) reapplying the imageable coating as desired by repeating steps (a) through (c) at least once without substantially removing the prior imaged coating before reapplying the imageable coating.

Abstract: A positive working, multi-layer thermally imageable element is disclosed. The element comprises a substrate, an underlayer, and a top layer. The top layer comprises a crosslinked polymeric material. The element may be thermally imaged and developed to form a lithographic printing plate.

Abstract: Photosensitive compositions comprising a phenol resin having a urea bond in the main chain, planographic printing plate precursors containing the photosensitive compositions, and methods for preparing planographic printing plates using the planographic printing plate precursors are disclosed. Planographic printing plates that exhibit good durability, good exposure visual image property, and good solvent resistance; particularly superior resistance to washing oil used in UV ink printing; and superior baking property are produced.

Abstract: The present invention provides an imageable element, which includes: a substrate; a crosslinked layer disposed on the substrate; and an imageable ink-receptive layer disposed on the crosslinked layer, the imageable ink-receptive layer including an ablation free imageable composition. The present invention provides methods of producing the above imaged element.

Abstract: The present invention provides a top coat layer for a printing plate precursor. The top coat layer includes polycyanoacrylate particles, but is substantially free of photothermal conversion material. The topcoat layer may be applied onto a thermally sensitive layer containing polycyanoacrylate particles and a photothermal conversion material. The top coat layer may reduce ablation during radiation exposure without adversely affecting printing plate performance.

Abstract: The present invention provides a negative-working photosensitive composition which can widen the preheat latitude upon exposure without increasing ablation, and a negative-working photosensitive lithographic printing plate. The negative-working photosensitive composition comprises (a) an alkali-soluble resin, (b) a compound capable of being crosslinked by an acid, (c) a compound capable of generating an acid by heat, (d) a photothermal converting agent, and (e) a sulfone compound represented by the following general formula (I). R—SO2—R′  (I) wherein R and R′ may be the same or different and represent a substituted or non-substituted alkyl, alkenyl, aryl, or heterocyclic group. The negative-working photosensitive lithographic printing plate comprises a photosensitive layer made of the negative-working photosensitive composition.

Abstract: The present invention relates to a light-sensitive composition containing: (i) at least one diazonium polycondensation product or at least one system that can be radically polymerized and consists of photoinitiators and unsaturated compounds which can be radically polymerized or at least one hybrid system consisting of a diazonium polycondensation product and a system that can be radically polymerized and consists of photo initiators and unsaturated compounds which can be radically polymerized, (ii) at least one binding agent and optionally one or more exposure indicators, one or more dyes for increasing the image contrast and one or more acids for stabilizing the light-sensitive composition which is characterized in that the binding agent essentially consists of units (A, B, C, D), whereby A corresponds to formula (I), B corresponds to formula (II), C corresponds to formula (III) and D corresponds to formula (IV). The invention also relates to the use thereof for coating printing plates.

Abstract: The present invention provides a thermally imageable composition, which includes an acid curable composition, an acid generator, a strong acid and optionally an infrared absorber. The present invention further provides an imageable element, which includes a substrate and a thermally imageable composition according to the present invention coated on a surface of the substrate. Also provided are methods of producing an imaged element according to the present invention.

Abstract: Processes for imaging and developing imageable elements useful as lithographic printing plate precursors either thermally or with ultraviolet radiation that use the same developer are disclosed. The imageable elements comprise a top layer and an underlayer. The top layer contains a phenolic polymer and a material that has either the o-benzoquinonediazide functionality or the o-diazonaphthoquinone functionality. The developer is a 20:80 to 80:20 mixture of (1) an aqueous alkaline developer that has a pH greater than 11 and contains about 2 wt % to about 8 wt % of an alkali metal silicate, and (2) a solvent based developer that contains about 0.5 wt % to about 15 wt % of an organic solvent or mixture of organic solvents.

Abstract: A process for forming a negative image useful as a printing plate is disclosed. A photosensitive assembly that comprises (a) a hydrophilic support, (b) a first layer that comprises a polymer that is soluble or dispersible in an aqueous alkaline solution, (c) a second layer that comprises at least one o-quinonediazide compound, and (d) an infrared absorbing compound is: (1) flood exposed with ultraviolet radiation; (2) imagewise exposed with infrared laser radiation; and (3) developed to produce the negative image.

Abstract: The present invention provides an imaging assembly comprising: (a) a modulator crystal comprising a first surface and a second surface substantially opposite to the first surface, wherein the first surface comprises an active area; and (b) a heating element for heating the modulator crystal to a temperature within a predetermined temperature range, wherein the heating element is positioned under the modulator crystal and comprises a first surface, wherein the heating element first surface faces the modulator crystal second surface and covers a portion of the modulator crystal second surface such that the active area of the first surface of the modulator crystal has a homogeneous temperature.

Abstract: Vesicular images are formed by thermal imaging of imageable layers containing thermally imageable vesicular imaging compositions. The vesicular images can be used as masks for imaging printing plate precursors. In one aspect, a printing plate precursor made up of a flexible substrate; a photosensitive layer that contains a negative working photosensitive composition; an optional barrier layer; and the imageable layer is thermally imaged to produce an integral mask. Blanket exposure through the mask with ultraviolet and/or visible radiation followed by development produces a printing plate. The method is especially suited for the production of flexographic printing plates.

Abstract: Disclosed is a thermally sensitive imagable article and compositions therefor. The imagable article comprises a coating on a substrate, the coating comprising an amino acid or amide, and a compound capable of generating an acid upon heating. The coating optionally comprises a radiation absorbing compound. When imagewise exposed the coating has the property that exposed regions become relatively insoluble in a developer liquid whereas regions that have not been exposed remain relatively soluble in the developer and dissolve in the developer, leaving the exposed substrate in those regions.

Abstract: The invention comprises a precursor to an imaged member comprising a dimensionally stable substrate including an imagable coating, on a surface thereon, wherein the non-coated dimensionally stable substrate comprises dimensionally stable paper comprising at least one of the following characteristics: (i) an elastic yield such that the tensile force required to exceed the elastic yield is greater than 60 Nmm−2; (ii) a percentage elongation of the paper under a tensile load or strain at the elastic yield point smaller than 1%; and (iii) a Young's Modulus under tensile load greater than 7 GPa. The invention further extends to a method of manufacturing an imaged member from an imaged member precursor of the invention.

Abstract: An acid generating agent useful for imaging photosensitive elements selected from compounds of formulae (I), (II) and (III). wherein R1 is selected from the group consisting of an unsubstituted and substituted hydrocarbon or aryl group; wherein X is selected from the group consisting of oxygen, sulfur and selenium; wherein Y is selected from the group consisting of sulfur, selenium and tellurium; wherein Ar1 is selected from the group consisting of an unsubstituted and substituted aryl group; wherein R2, R3 and R4 are individually selected from the group consisting of an unsubstituted and substituted hydrocarbon or aryl group or any two of them are bonded together to form a ring structure; and wherein R5 and R6 are individually selected from the group of an unsubstituted and substituted hydrocarbon or aryl group, or are bonded to each other to form a ring structure.

Abstract: The present invention provides a positive working imageable composition, which includes a hydroxyfunctional resin comprising a covalently bound radiation sensitive group capable of increasing the solubility of the imageable composition in an alkaline developer upon exposure to radiation; and an isocyanate crosslinking agent. The present invention further provides an imageable element, which includes a substrate and an imageable composition according to the present invention coated on a surface of the substrate and a method of producing an imaged element according to the present invention. Also provided is a radiation sensitive hydroxyfunctional resin including a covalently bound radiation sensitive group capable of increasing solubility in an alkaline developer of an imageable composition derived therefrom upon exposure of the imageable composition to radiation.