Abstract: A presensitized lithographic plate comprises a support and a hydrophilic image-recording layer. The hydrophilic image-recording layer contains a hydrophilic polymer and an agent capable of converting hydrophilic to hydrophobic when the agent is heated. The hydrophilic polymer comprises a main chain and branched chains. Each of the branched chain comprises a hydrophilic chain having a molecular weight in the range of 200 to 1,000,000. A hydrophilic substrate and a lithographic printing process are also disclosed.

Abstract: The present invention provides a planographic printing plate precursor comprising a photosensitive layer on a support, the photosensitive layer including an infrared absorbent, a radical polymerization initiator and a radical polymerizing compound, the photosensitive layer being recordable with irradiation with an infrared ray, and being at least one of soluble and dispersible in water.

Abstract: A lithographic printing plate precursor having a support, and an image recording layer containing a microcapsule and (A) an active light absorber, removable by a printing ink and/or fountain solution on the support, characterized in that the microcapsule is a specific urethane type microcapsule, and a lithographic printing method using the same.

Abstract: A lithographic printing plate precursor comprises: a support; and an image recording layer that contains image forming particles and a non-water-soluble binder, the non-water-soluble binder interacting with the surface of the image forming particles. A lithographic printing plate precursor comprises: a support; and an image recording layer that contains a polymer binder and particles, wherein the particles are microcapsules having a polymerizable functional group as a wall material.

Abstract: A heat-sensitive lithographic printing plate precursor comprising a support having provided thereon (A) an ink-receiving layer and (B) a hydrophilic layer comprising 80 to 99 parts by weight of a colloidal particulate oxide or hydroxide of at least one element selected from a group consisting of beryllium, magnesium, aluminum, silicon, titanium, boron, germanium, tin, zirconium, iron, vanadium, antimony and a transition metal, and 1 to 20 parts by weight of a polyacrylic acid having a weight-average molecular weight of more than 50,000, and at least one of the ink-receiving layer and the hydrophilic layer including a light-heat converting agent.

Abstract: A lithographic printing plate precursor comprising: a support; an image recording layer comprising (A) an actinic ray absorber, (B) a polymerization initiator, and (C) a polymerizable compound, wherein the image recording layer is capable of being removed with at least one of a printing ink and a fountain solution; and an overcoat layer comprising an inorganic laminar compound. And a lithographic printing method comprising: mounting a lithographic printing plate precursor on a printing press; imagewise exposing the lithographic printing plate precursor with laser beams; and feeding at least one of a printing ink and a fountain solution to the lithographic printing plate precursor to remove a laser beams non-exposed area in an image recording layer; and performing printing.

Abstract: A process for producing polymer fine particles comprising: dispersing a solution obtained by dissolving a hydrophobic polymer in a solvent immiscible with water in an aqueous phase comprising fine particles of an oxide or hydroxide of at least one element selected from the group consisting of elements belonging to 2 to 15 groups in the periodic table using a surfactant; or dispersing a solution obtained by dissolving a hydrophobic polymer in a solvent immiscible with water in an aqueous phase comprising a water-soluble resin; and then removing the solvent from the oil droplets to form polymer fine particles dispersed in water.

Abstract: The present invention provides a planographic printing plate precursor comprising a photosensitive layer on a support, the photosensitive layer including an infrared absorbent, a radical polymerization initiator and a radical polymerizing compound, the photosensitive layer being recordable with irradiation with an infrared ray, and being at least one of soluble and dispersible in water.

Abstract: On-press developing method of a lithographic printing plate precursor, the lithographic printing plate precursor comprising an image-forming layer which comprises a hydrophobizing precursor, and the method comprising fountain solution-clarifying means which comprises: aggregating a hydrophobizing precursor mingled in a fountain solution and removing the aggregated hydrophobizing precursor by filtration; or adding a coagulant to a fountain solution and filtering the fountain solution.

Abstract: A lithographic printing plate precursor which comprises a support having provided thereon a layer containing a light-to-heat converting agent as a lower layer and a hydrophilic photosensitive layer containing light-to-heat convertible metallic fine particles which change to hydrophobic with the conversion of light to heat as an upper layer.

Abstract: A lithographic printing plate precursor which comprises a support having provided thereon a layer comprising a hydrophilic medium, wherein the layer comprising a hydrophilic medium contains a hydrophobitization precursor having a hydrophilic surface and a light/heat converting agent which is hydrophilic in itself, or at least on the surface.

Abstract: There is provided a lithographic printing plate precursor having good on-machine development quality, and moreover high sensitivity and high printing durability, which comprises a support having provided thereon an image forming layer containing (1) at least one ingredient selected from the group consisting of fine particles containing a compound having two or more vinyloxy groups and microcapsules encapsulating a compound having two or more vinyloxy groups, (2) a light-to-heat conversion agent, (3) a hydrophilic resin and (4) an acid precursor.

Abstract: On-press developing method of a lithographic printing plate precursor, the lithographic printing plate precursor comprising an image-forming layer which comprises a hydrophobizing precursor, and the method comprising fountain solution-clarifying means which comprises: aggregating a hydrophobizing precursor mingled in a fountain solution and removing the aggregated hydrophobizing precursor by filtration; or adding a coagulant to a fountain solution and filtering the fountain solution.

Abstract: A heat-sensitive lithographic printing plate precursor comprising a support having provided thereon (A) an ink-receiving layer and (B) a hydrophilic layer comprising 80 to 99 parts by weight of a colloidal particulate oxide or hydroxide of at least one element selected from a group consisting of beryllium, magnesium, aluminum, silicon, titanium, boron, germanium, tin, zirconium, iron, vanadium, antimony and a transition metal, and 1 to 20 parts by weight of a polyacrylic acid having a weight-average molecular weight of more than 50,000, and at least one of the ink-receiving layer and the hydrophilic layer including a light-heat converting agent.

Abstract: A method of producing a lithographic printing plate comprising a step of providing on a support a layer has a hydrophobic surface and comprises an oxidizable material and a reducible material, a step of irradiating imagewise with active rays in the presence of a photocatalytic metal compound, wherein the oxidizable material in the irradiated area is decomposed imagewise to convert the layer surface in the irradiated area surface into hydrophilic property and form an imagewise distribution of hydrophilic areas and hydrophobic areas: and a lithographic printing plate precursor used in the aforesaid method. In accordance with this method, no development-processing is required for plate-making, the plate-making operations can be carried out as the plate precursor is mounted on a printing press, and the lithographic printing plate made can have an excellent press life and hardly generates staining.

Abstract: A process for producing polymer fine particles comprising: dispersing a solution obtained by dissolving a hydrophobic polymer in a solvent immiscible with water in an aqueous phase comprising fine particles of an oxide or hydroxide of at least one element selected from the group consisting of elements belonging to 2 to 15 groups in the periodic table using a surfactant; or dispersing a solution obtained by dissolving a hydrophobic polymer in a solvent immiscible with water in an aqueous phase comprising a water-soluble resin; and then removing the solvent from the oil droplets to form polymer fine particles dispersed in water.

Abstract: The present invention provides a planographic printing plate precursor comprising a photosensitive layer on a support, the photosensitive layer including an infrared absorbent, a radical polymerization initiator and a radical polymerizing compound, the photosensitive layer being recordable with irradiation with an infrared ray, and being at least one of soluble and dispersible in water.

Abstract: A direct drawing type lithographic printing plate precursor comprising a water-resistant support having provided thereon an image receiving layer, wherein the image receiving layer comprises particles having rough surface composed of core particles having on the surfaces thereof fine particles adhered, and a binder resin comprising a complex composed of a resin containing a siloxane bond in which a silicon atom is connected with an oxygen atom and an organic polymer containing a group capable of forming a hydrogen bond with the resin containing a siloxane bond. According to the use of the direct drawing type lithographic printing plate precursor of the present invention, images free from not only background stain over an entire surface but also dot-like stain can be formed thereon. Also, the direct drawing type lithographic printing plate precursor can prepare a lithographic printing plate providing a great number of printed matter having clear images free from disappearance or distortion of image.

Abstract: A method of producing a lithographic printing plate which comprises subjecting a printing plate precursor comprising a support having a metallic compound layer which has a photo-catalytic property and a hydrophilic surface and bears light-heat convertible minute particles on the surface thereof to imagewise irradiation of heat mode to convert polarity of the metallic compound layer, thereby forming an imagewise hydrophobic region. The lithographic printing plate can be repeatedly employed.

Abstract: A lithographic printing plate precursor which comprises a support having provided thereon a layer containing a light-to-heat converting agent as a lower layer and a hydrophilic photosensitive layer containing light-to-heat convertible metallic fine particles which change to hydrophobic with the conversion of light to heat as an upper layer.