There are free radical scavengers of formula (P.sub.m-L).sub.n-T.sub.q. Also provided are negative-working lithographic printing plate precursors comprising a hydrophilic substrate and a NIR photopolymerizable or UV-violet photopolymerizable imageable layer coated on the hydrophilic layer, the imageable layer also being photopolymerizable by visible light, the imageable layer having an outer surface and a thickness, the outer surface of the imageable layer being uniformly, and partially or completely crosslinked down to a depth corresponding to at most about 70% of the thickness of the imageable layer.

A lithographic printing plate precursor is disclosed including a support and a coating comprising (i) a photopolymerisable layer including a polymerisable compound, a photoinitiator and an asymmetrically substituted infrared absorbing compound.

A lithographic printing plate precursor has an image-recording layer on a hydrophilic support, in which the image-recording layer contains an infrared absorbing dye that decomposes by exposure to an infrared ray and a color developer that develops color due to the exposure to an infrared ray. A method for producing a lithographic printing plate includes image-exposing the lithographic printing plate precursor using an infrared laser.

A lithographic printing plate precursor has an image-recording layer on a hydrophilic support, wherein the image-recording layer includes a polymer particle including an addition polymerization resin having a hydrophilic structure and a crosslinking structure. A method for producing a lithographic printing plate uses the lithographic printing plate precursor. A polymer particle includes an addition polymerization resin having a hydrophilic structure and a crosslinking structure. A composition includes the polymer particle.

A lithographic printing plate precursor including a hydrophilized aluminum support, and a water-soluble or water-dispersible negative type image recording layer provided on the aluminum support, in which an arithmetic average height Sa of a surface of an outermost layer on a side where the image recording layer is provided is in a range of 0.3 μm to 20 μm; a method of producing a lithographic printing plate precursor; a lithographic printing plate precursor laminate formed of the lithographic printing plate precursor; a plate-making method for a lithographic printing plate; and a lithographic printing method.

IR-sensitive lithographic printing plate precursors provide a stable print-out image using a unique IR radiation-sensitive composition in an infrared radiation-sensitive image-recording layer. This IR radiation-sensitive composition includes: (1) a free radical initiator composition comprising a borate compound; (2) a free radically polymerizable composition; (3) an acid-sensitive color-changing compound that is represented by the Formula (I) identified herein; (4) an infrared absorber material; and a (5) color-changing compound of Formula (III) or Formula (IV) identified herein. After IR imaging, the exposed precursors exhibit desirable printout images especially in the 600-700 nm region of the electromagnetic spectrum and especially for observation using electronic sensing devices. The imaged precursors can be developed off-press or on-press.

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 %.

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##