Provided are a lithographic printing plate precursor comprising: an image-recording layer on a support, in which the image-recording layer includes a dye compound having a decomposable group that is decomposed by an acid, heat, or both and a structure in which decomposition of the decomposable group opens a ring or desorbs a leaving group and an electron-donating polymerization initiator, a method for producing a lithographic printing plate in which the lithographic printing plate precursor is used, and a color-developing composition including a dye compound having a decomposable group that is decomposed by an acid, heat, or both and a structure in which decomposition of the decomposable group opens a ring or desorbs a leaving group and an electron-donating polymerization initiator.

A polymerizable composition is provided, including an infrared absorber, a polymerization initiator, a polymerizable compound, and a polymer binder, wherein the polymer binder is a particulate random copolymer, and the polymer binder has structural units derived from a polymerizable polyalkylene oxide-based monomer and a polymerizable nitrogen-free non-polyalkylene oxide-based monomer. The polymerizable composition may be used in the production of imageable elements or printing plates.

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 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 %.

A negative-working infrared radiation-sensitive lithographic printing plate precursor can be imaged and developed on-press to provide a lithographic printing plate. Such precursor has an initiator composition that contains compound A of Structure (I) and one or more compounds collectively as compound B of Structure (II) or Structure (III):

##STR00001##

wherein R.sub.1, R.sub.2, R.sub.3, R.sub.4, R.sub.5 and R.sub.6 are independently alkyl or alkoxy groups each having 2 to 9 carbon atoms; at least one of R.sub.3 and R.sub.4 is different from R.sub.1 or R.sub.2; the difference of total number of carbon atoms in R.sub.1 and R.sub.2 and the total number of carbon atoms in R.sub.3 and R.sub.4 is 0 to 4; the difference of total number of carbon atoms in R.sub.1 and R.sub.2 and the total number of carbon atoms in R.sub.5 and R.sub.6 is 0 to 4; and X.sub.1, X.sub.2 and X.sub.3 are the same or different anions.

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.

A planographic printing plate precursor includes: a support; and an image recording layer which includes a radical initiator, a radical polymerizable component, and a radiation absorption compound, and in which the image recording layer shows two or more peaks of a radical generation amount in a radical generation amount-versus-time curve after exposure to image forming radiation, in which the radical initiator includes an electron-donating radical initiator and an electron-accepting radical initiator, and the radiation absorption compound comprises a compound represented by the following Formula 1. ##STR00001##

Provided is a lithographic printing plate precursor having an aluminum support and an image-recording layer formed on the aluminum support, in which the image-recording layer contains resin particles A that have an ethylenically unsaturated group and a compound B that has an ethylenically unsaturated group other than the resin particles A and has an ethylenically unsaturated bond valence of 1.5 mmol/g or more. Also provided are a method for preparing lithographic printing plate or a lithographic printing method using the lithographic printing plate precursor.

A lithographic printing plate precursor is disclosed including on a support a coating comprising (i) a photopolymerisable layer including a polymerisable compound, a first infrared absorbing dye including at least one electron withdrawing substituent and a photoinitiator; and (ii) a top layer provided above the photopolymerisable layer which includes a second infrared absorbing compound which includes a thermocleavable group which transforms into a group which is a stronger electron-donor upon exposure to heat and/or IR radiation, and is capable of forming a print-out image upon exposure to heat and/or IR radiation.

A curable composition includes a salt compound having a) an organic anion in which, in Hansen solubility parameter, δd is 16 or more, δp is 16 or more and 32 or less, and δH is 60% or less of δp and b) a counter cation. A lithographic printing plate precursor having an image-recording layer containing the curable composition, a method for producing a lithographic printing plate using the lithographic printing plate precursor, and a compound that is used in the image-recording layer in the lithographic printing plate precursor are also set out.