Provided is an on-press development type lithographic printing plate precursor having a support, an image-recording layer, and an outermost layer in this order, in which the image-recording layer contains an infrared absorber, an electron-donating polymerization initiator, and a polymerizable compound, HOMO of the infrared absorber - HOMO of the electron-donating polymerization initiator is 0.60 eV or less, and the outermost layer contains a discoloring compound. Also provided are a method of preparing a lithographic printing plate and a lithographic printing method in which the on-press development type lithographic printing plate precursor is used.

A lithographic printing plate precursor is disclosed including a coating comprising a polymerisable compound, an infrared absorbing dye, a photoinitiator including a trihaloalkyl group and a borate compound.

There is provided a copolymer having the general structure below, wherein a, b, and d are molar ratios varying between about 0.01 and about 0.90 and c is a molar ratio varying between about 0.01 and about 0.90; A1 represents monomer units comprising a cyano-containing pendant group in which the cyano is not directly attached to the backbone of the copolymer; A2 represents monomer units comprising two or more hydrogen bonding sites; A3 represents monomer units that increase solubility in organic solvents; and A4 represents monomer units that increase solubility in aqueous alkaline solutions. There is also provided a near-infrared radiation-sensitive coating composition comprising this copolymer as well as a positive-working thermal lithographic printing plate comprising a near-infrared radiation-sensitive coating comprising this copolymer, a method of producing such a printing plate, and finally a method of printing using such a printing plate. Formula (I).

A system for exposing a heat and/or light sensitive printing plate precursor including a coating on a support includes a platesetter including a laser head for generating a laser beam to create an image, and the platesetter further includes an electrostatic generator capable of electrostatically charging the surface of the coating.

Provided is a photosensitive resin composition, including: a polymer compound which has a polycyclic structure and a sulfonamide group in a main chain thereof; and an infrared absorbent, wherein the polycyclic structure has at least one structure selected from the group consisting of a fused cyclic hydrocarbon structure and a fused polycyclic aromatic structure.

A positive-working lithographic printing plate precursor is disclosed which comprises on a support having a hydrophilic surface or which is provided with a hydrophilic layer a heat and/or light-sensitive coating including an infrared absorbing agent, said heat and/or light-sensitive coating comprising a first layer comprising a binder including a monomeric unit including a sulfonamide group; characterized in that the binder further comprises a monomeric unit including a phosphonic acid group or a salt thereof, and that the monomeric unit comprising the phosphonic acid group is present in an amount comprised between 2 mol % and 15 mol %.

An object of the present invention is to provide a waterless lithographic printing plate precursor that sufficiently repels ink, which tends to adhere to non-imaging areas, and maintains its repelling effects, and a printing method using a waterless lithographic printing plate obtained from the waterless lithographic printing plate precursor. The following are provided: a lithographic printing plate precursor having at least a heat sensitive layer and an ink repellent layer, wherein the ink repellent layer contains an ink repelling, the ink repellent liquid having a boiling point of not less than 150° C. at 1 atmospheric pressure; and a method of producing a printed material, comprising the step of transferring an ink containing a photosensitive component in an amount from 10% by mass to 50% by mass to a printing substrate using a lithographic printing plate and then irradiating the printing substrate with ultraviolet light, wherein the lithographic printing plate precursor has at least an ink repellent layer on a substrate, an ink repellent liquid contained in the ink repellent layer has a surface tension of 30 mN/m or less.

An object of the invention is to provide a water-based lithographic printing method that is excellent in printing quality and environmental aspects. The invention concerns a method of producing a printed material, including the steps of: allowing a water-based ink to adhere to a surface of a heat sensitive layer of a lithographic printing plate having a surface on which an ink repelling layer and the heat sensitive layer exist; and transferring the adhering water-based ink directly or via a blanket to a printing substrate.

Disclosed is a infrared radiation sensitive positive-working imageable element. The imageable element comprises: (a) a substrate, (b) an inner coating covering the substrate, and (c) an outer coating covering the inner coating. The inner coating comprises a repeating unit derived from a maleimide monomer and a (meth)acrylamide monomer, and a polymer hinder P that is soluble in an alkaline developing solution; and the outer coating comprises an infrared radiation absorbing compound and a polymer binder Q which is different from that in the inner coating. The imageable element is designed such that same is not only sensitive to radiation with a maximum wavelength of 700-1200 nm, but also has a good resistance to chemical solvents when used as a lithographic printing plate precursor, and same is not easily corroded and dissolved by printing chemicals during use, thus facilitating the prolonging of the service life of a lithographic printing plate.

A method for processing a heat-sensitive positive-working lithographic printing plate material is disclosed which comprises at least two layers: —a first layer comprising an oleophilic resin and/or a vinyl acetal (co)polymer; —a second layer comprising a (co)polymer which is located between the support and the first layer; comprising the steps of: —treating the plate material with an alkaline development solution, —treating the plate material with a first gum solution and consecutively with a second gum solution which are configured as a cascade whereby the second gum solution overflows into the first gum solution; and which gum solutions include a buffer; characterized in that the pH of the first gum solution reaches a steady state value above the pKa value of the (co)polymer present in the second layer.