Abstract: An improved hydrophilized substrate for planographic printing is disclosed. The substrate contains a support and a hydrophilic layer over the support. The hydrophilic layer contains titanium dioxide (titania) particles. In one embodiment, the hydrophilic layer contains a mixture of coated and uncoated titanium dioxide particles, and, optionally, alumina particles. A method for preparation of the substrate and a printing member comprising the substrate are also disclosed.

Abstract: A positive working lithographic plate precursor comprising a support having a hydrophilic surface and a coating thereon comprising a positive working, photosensitive composition and an aryl alkyl polysiloxane. A method of preparing a positive working lithographic plate precursor comprising coating on a support having a hydrophilic surface a coating comprising, in admixture, a positive working photosensitive composition and an aryl alkyl polysiloxane.

Abstract: The present invention relates to a printing plate precursor with an overcoat, where the printing plate precursor is preferably developable on a printing press after imagewise exposure. The printing plate precursor comprises the following components: (a) at least one polymeric organic binder, soluble in water or in organic solvents having a water content of at least 50 wt.

Abstract: A polyvinyl acetal copolymer compound comprises the units A, B, C and D, wherein A is present in an amount of 0.5 to 30 wt.

Abstract: A method of producing a resist pattern on a substrate using a precursor which comprises a coating composition which includes a heat sensitive polymeric substance having functional groups Q thereon (wherein groups Q may be siloxane or optionally substituted fluoroalkyl groups) wherein groups Q cause the polymeric substance to have a reduced adhesive interaction with ink for use in waterless lithographic printing compared to aid polymeric substance in the absence of said groups, the method including the step of causing the patternwise application of heat to said coating composition and optional development thereby to define ink accepting areas in heat exposed areas and non-ink accepting areas in non-exposed areas.

Abstract: A method for applying a matting layer to a radiation-sensitive layer of a printing plate precursor comprises: (a) providing a matting composition comprising a polymer and a solvent, wherein the matting composition has a solid content of more than 10% and no more than 50% by weight based on the total composition; and (b) spraying the matting composition on the radiation-sensitive layer using an electrostatically aided rotary atomizer having a bell speed of more than 10,000 rpm, wherein the distance between the bell and the radiation-sensitive layer to be coated is less than 50 cm.

Abstract: A method for forming an image on a printing plate intermediate having a radiation transparent removable coating layer is disclosed. An image mask, opaque to ultraviolet radiation, is applied to the coating layer with an ink jet system. After the plate intermediate is exposed with ultraviolet radiation, the image mask and coating layer are removed, and plate intermediate developed.

Abstract: A positive-working imaging member is composed of a heat-sensitive surface imageable layer having a heat-sensitive polymer containing heat-activatable sulfoimino, sulfoalkyl, or sulfoamide groups, and a photothermal conversion material. Upon application of thermal energy, such as from IR irradiation, the sulfonate groups decompose rendering exposed areas more hydrophilic. The exposed imaging member can be contacted with a lithographic printing ink and used for printing without post-imaging wet processing. This imaging member is particularly useful for direct write imaging using IR lasers or thermal printing heads.

Abstract: A planographic printing member precursor comprises a first component, for example a hydroxy group containing polymer, and a second component which may be a siloxane or a compound of general formula (I): wherein M represents a silicon or a titanium atom and each of R1, R2, R3 and R4 is independently selected from hydrogen or halogen atoms; a hydroxy group, an optionally substituted alkyl, alkenyl or alkynyl group; an optionally substituted alkoxy group; or an optionally substituted saturated or unsaturated cyclic or heterocyclic group. On exposure, the second component reacts with the first component to define an oleophobic/hydrophilic material in exposed areas and in non-exposed areas the second component is removed, on processing of the precursor.

Abstract: An imaging member, such as a negative-working printing plate or on-press cylinder, can be prepared with a hydrophilic imaging layer comprised of a heat-sensitive hydrophilic polymer having ionic moieties and a polymer grafted carbon as a photothermal conversion material. The heat-sensitive polymer and polymer grafted carbon can be formulated in water or water-miscible solvents without agglomeration. In the imaging member, the polymer reacts to provide increased hydrophobicity in areas exposed to energy that provides or generates heat. For example, heat can be supplied by laser irradiation in the IR region of the electromagnetic spectrum. The heat-sensitive polymer is considered “switchable” in response to heat, and provides a lithographic image without wet processing.

Abstract: A heat-sensitive composition, for example a coating on a lithographic printing plate, comprises a carboxylic acid derivative of a cellulosic polymer. The composition may contain a radiation absorbing compound and suitable electromagnetic radiation, preferably infra-red radiation, may be used to heat the composition imagewise. The presence of the cellulosic polymer enhances resistance to certain organic liquids.

Abstract: A replenisher composition developing exposed radiation-sensitive printing plate precursors for plate/developer systems in which the electrical conductivity of the developer does not decrease to the same extend as the activity of the developer decreases or even increases is disclosed. A method for developing exposed radiation-sensitive printing plates using the replenisher composition is also disclosed.

Abstract: An aqueous developer for imageable elements that contain a radiation-sensitive initiator system and at least one free radical polymerizable material is disclosed. The developer develops these plates quickly, with high throughput, but with no sludge formation in the developing process. The developer contains water, a buffer, and one or more filter dyes and/or one of more free radical inhibitors. The imageable elements are useful as printing plates.

Abstract: A photoconductive composition useful for the preparation of printing plates is disclosed. The composition comprising an organic photoconductor, a charge carrier generating material, and a binder comprising a mixture of at least two copolymers. Copolymer (a) comprises an aromatic vinyl monomer, such as styrene or a substituted styrene, and maleic acid anhydride ring opened with a first aliphatic alcohol.

Abstract: A printing plate useful in lithographic printing is prepared by the process comprising: (a) applying an alkali soluble composition comprising at least one polymer composition to a hydrophilic surface on a substrate to provide the surface face with at least one layer which is alkali soluble at a pH in the range of about 6.0 to 14.0; (b) imaging the coated substrate electrostatically with a toner composition; (c) heating the imaged substrate a first time to a temperature greater than the glass transition temperature of the toner composition; (d) contacting the imaged substrate with an aqueous alkaline solution having a pH in the range of about 6.0 to about 14.0; and (e) heating the imaged substrate a second time to a temperature greater than the glass transition temperature of the toner composition. This printing plate is capable of long runs on press with good image quality and advantageously minimizes the occurrence of undesirable background toner “specking” on press.

Abstract: A laser imager comprises a modulator with an array of electrodes to control picture elements individually or by groups to produce images on a recording plane. The light intensity of each picture element or group of elements is determined by electrical potential applied between sets of controlling electrodes. These levels can be manually set or automatically exercised during a balancing routine through a feed-back loop using a photodetector to monitor and detect elements producing a light intensity higher than a set value. Control means assign to these elements a “correction voltage” to lower the density of elements they control. These correction values obtained after one or repeated balancing routines are stored in a memory and are used during the imaging cycle to produce images of substantially equal intensity on the recording medium.

Abstract: The present invention is a process for fabricating color images using an ink jet printing system. Color formation is achieved using color dye forming chemistry used in silver halide photography. The images formed in this process are light fast, water fast and of a color gamut range similar to photographic media. The image substrate can be either a transparency or opaque media and the final image will be of photorealistic quality.

Abstract: A method for preparing a substrate for a planographic printing member is disclosed. A liquid that contains water; a soluble alkali metal silicate, preferably sodium silicate; and a dispersed particulate material is coated on a support, to produce a hydrophilic layer on the support. A layer of image material may be coated over the hydrophilic layer to produce a planographic printing member. In one embodiment the liquid contains a mixture of two particulate materials, preferably alumina and titanium dioxide. The substrate has a surface roughness of about 0.1 &mgr;m to 2 &mgr;m. The substrate is suitable for preparing a planographic printing member processable to a resolution of 10 &mgr;m or less and in which the dots having a roundness of less than 2 are formed.

Abstract: A thermally imageable element, useful as a lithographic printing plate precursor is disclosed. The element comprises a hydrophilic substrate; an underlayer comprising a first polymeric material; and an ink-receptive top layer comprising a second polymeric material. Preferably, the top layer comprises a compound that functions as a solubility-suppressing component. The solubility-suppressing component may be a separate dissolution inhibitor compound and/or the second polymeric material may also function as a solubility-suppressing component. On thermal exposure the exposed regions of the top layer becomes more readily soluble in an aqueous developer, allowing the developer to remove the top layer and reveal the surface of the hydrophilic substrate. The lithographic printing plate thus formed has excellent properties, including the absence of sludging of the developer.

Abstract: A printing plate is prepared by the process comprising: (a) providing a substrate; and (b) applying by ink jetting to the substrate a fluid composition comprising an acidic polymeric compound and a second compound comprising a pyridyl group in non-aqueous solvent, providing a printing plate that is ready-to-use on a press without having to develop it. The printing plate of this invention is capable of extended press run length and advantageously avoids the costly and time-consuming need of chemical development.