Abstract: A method to reduce effluence during or immediately after imaging of a printing plate is described. In one embodiment of the invention, the method comprises: (a) applying to a substrate a coating composition comprising a photothermal converter and at least one polymer comprising thiosulfate groups to obtain a coating; and (b) applying a water soluble topcoat to the coating. Preferably, the water soluble topcoat does not comprise a photothermal converter. In another embodiment of the invention, the method comprises applying to a substrate a composition comprising: (a) a photothermal converter; (b) at least one polymer comprising thiosulfate groups; and (c) an additive selected from the group consisting of diazonium, iodonium, copper(I), alkoxypyridinium or maleimide additives.

Abstract: A method to reduce effluence during or immediately after imaging of a printing plate is described. In one embodiment of the invention, the method comprises: (a) applying to a substrate a coating composition comprising a photothermal converter and at least one polymer comprising thiosulfate groups to obtain a coating; and (b) applying a water soluble topcoat to the coating. Preferably, the water soluble topcoat does not comprise a photothermal converter. In another embodiment of the invention, the method comprises applying to a substrate a composition comprising: (a) a photothermal converter; (b) at least one polymer comprising thiosulfate groups; and (c) an additive selected from the group consisting of diazonium, iodonium, copper(I), alkoxypyridinium or maleimide additives.

Abstract: An imaging member is composed of a hydrophilic imaging layer having a hydrophilic heat-sensitive polymer containing heat-activatable thiosulfate groups, and optionally a photothermal conversion material. Upon application of energy that generates heat, such as from IR irradiation, the polymer is crosslinked and rendered more hydrophobic. The imaging layer is disposed on an interlayer on a support, which interlayer comprises a Group IVB element (such as titanium, hafnium or zirconium) compound for improved mechanical and imaging properties. The exposed imaging member can be contacted with a lithographic printing ink and used for printing with or without post-imaging wet processing. This imaging member is particularly useful for direct write imaging using IR lasers or thermal printing heads.

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 an infrared radiation sensitive oxonol dye that has a &lgr;max of greater than 700 nm. The heat-sensitive polymer and IR dye can be formulated in water or water-miscible solvents to provide highly thermal sensitive imaging compositions. 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 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 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: Infrared radiation-sensitive compounds have been found that are represented by Structure DYE as follows: wherein R is a secondary or tertiary amine that contains no heterocyclic group, R1 and R2 are independently carbocyclic aromatic groups, and M+ is a monovalent cation. These compounds have a &lgr;max above 700 nm and are can be used in a number of photosensitive or heat-sensitive imaging materials.

Abstract: Infrared radiation-sensitive heterocyclic oxonol compounds have been found that are represented by Structure DYE as follows: wherein R is a secondary or tertiary amine, R1 and R2 are independently heterocyclic or carbocyclic aromatic groups, and M+ is a monovalent cation, provided that at least one of R, R1 and R2 contains at least one heterocyclic group. These compounds have a &lgr;max above 700 nm and are can be used in a number of photosensitive or heat-sensitive imaging materials.

Abstract: A drop-on-demand ink jet printing apparatus for printing proof images and then producing at least one lithographic printing plate in response to an input image includes a computer adapted to receive the input digital image and a plurality of ink reservoirs for providing inks of different colors for printing proof images and at least one lithographic ink reservoir for producing a lithographic printing plate. First print heads coupled to a proof image receiver and responsive to the computer for transferring particular inks onto the proof image receiver for producing proof images; and a second print head responsive to the computer for transferring lithographic ink from the lithographic ink reservoir to form an image pattern on the lithographic printing plate.

Abstract: An imaging member is composed of a heat-sensitive imaging layer having a heat-sensitive hyperbranched polymer containing heat-sensitive active end groups, and optionally a photothermal conversion material. Upon application of energy that generates heat, such as from IR irradiation, the polymer is rendered either more hydrophobic or hydrophilic depending upon the type of heat-sensitive active end groups present in the polymer. The exposed imaging member can be contacted with a lithographic printing ink and used for printing with or without post-imaging wet processing. This imaging member is particularly useful for direct write imaging using IR lasers or thermal printing heads.

Abstract: An imaging member, such as a printing cylinder, is composed of a hydrophilic imaging layer formed from a heat-sensitive composition (for example, by spray coating) having a hydrophilic heat-sensitive polymer containing heat-activatable thiosulfate groups, and optionally a photothermal conversion material. Upon application of energy that generates heat, such as from IR irradiation, the polymer is crosslinked and rendered more hydrophobic. The exposed imaging member can be contacted with a lithographic printing ink and a fountain solution and used for printing with or without post-imaging wet processing. This imaging member is particularly useful for direct write imaging using IR lasers or thermal printing heads. In preferred embodiments, the imaging member is an on-press printing cylinder that is prepared, imaged and used on press.

Abstract: An infrared imaging composition contains two essential components, a non-basic infrared radiation absorbing material (such as carbon black), and a phenolic resin that is either mixed or reacted with an o-diazonaphthoquinone derivative. These compositions are useful in positive-working or negative-working imaging elements such as lithographic printing plates that can be adapted to direct-to-plate imaging procedures.

Abstract: An ink jet printing apparatus responsive to an input digital image for producing a halftone image on a receiver, such as a lithographic plate, having halftone dots with each halftone dot being formed by one or more microdots in a screen dot of selectable areas, including an adjustable printhead for delivering different volumes of ink droplets which, when they contact the receiver, forming microdots of different areas according to the selected screen dot size. The apparatus delivers ink to the printhead and is responsive to a selected screen dot size and the digital image to control the printhead to form ink droplets of different volumes to produce a halftone image on the receiver.

Abstract: An imaging member is composed of a hydrophilic imaging layer having a hydrophilic heat-sensitive polymer containing heat-activatable thiosulfate groups, and optionally a photothermal conversion material. Upon application of energy that generates heat, such as from IR irradiation, the polymer is crosslinked and rendered more hydrophobic. The exposed imaging member can be contacted with a lithographic printing ink and a fountain solution and used for printing with or without post-imaging wet processing. This imaging member is particularly useful for direct write imaging using IR lasers or thermal printing heads.

Abstract: A photosensitive composition can be used to prepare negative-working photosensitive elements such as lithographic printing plates. The composition includes a first photocrosslinkable aromatic resin having photocrosslinkable groups and a number average molecular weight of at least about 1500. Also included is a polymerizable monomer, a photocrosslinkable polyester, a photoinitiator, and an aromatic thiazoline photosensitizer. The photosensitive resins are present at a total weight ratio to the monomer of at least 1.5:1.

Abstract: A photosensitive composition can be used to prepare negative-working photosensitive elements such as lithographic printing plates. The composition includes a first photocrosslinkable aromatic resin having photocrosslinkable groups and a number average molecular weight of at least about 1500. Also included is a mixture of a polyalkyleneglycol diacrylate and polyacrylate polymerizable monomers, a photocrosslinkable polyester, a photoinitiator, and a photosensitizer. The photosensitive resins are present at a total weight ratio to the polymerizable monomers of at least 1.5:1.

Abstract: An imaging member, such as a negative-working printing plate, can be prepared using a heat sensitive imaging layer comprised of a heat-sensitive vinyl polymer and optionally a photothermal conversion material. The heat-sensitive polymer has recurring units containing a cyclic anhydride that decarboxylates upon application of thermal energy (such as from IR irradiation), rendering the polymer more hydrophobic in IR exposed areas. Upon contact with a neutral or acidic pH solution, the polymer is then rendered more hydrophilic in unexposed areas.

Abstract: A photosensitive composition can be used to prepare negative-working photosensitive elements such as lithographic printing plates. The composition includes a first photocrosslinkable aromatic resin having photocrosslinkable groups and a number average molecular weight of at least about 1500. Also included is a polymerizable monomer, a photocrosslinkable polyester and a photoinitiator. The photosensitive resins are present at a total weight ratio to the monomer of at least 1.5:1.

Abstract: A photosensitive composition can be used to prepare negative-working photosensitive elements such as lithographic printing plates. The composition includes a first photocrosslinkable aromatic resin having photocrosslinkable groups and a number average molecular weight of at least about 1500. Also included is a polymerizable monomer, a photocrosslinkable polyester, a photocrosslinkable copolymer of styrene and maleic anhydride, and a photoinitiator. The photocrosslinkable resins are present at a total weight ratio to the polymerizable monomer of at least 1.5:1.

Abstract: A laser dye-ablative recording element comprising a support having thereon a dye layer comprising a yellow dye dispersed in a polymeric binder, the dye layer having an infrared-absorbing material associated therewith, the yellow dye comprising curcumin.