A lithographic printing plate precursor including an image recording layer containing an infrared absorber represented by Formula I, on a support, and a method of producing a lithographic printing plate and a lithographic printing method using the lithographic printing plate precursor. ##STR00001##

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.

The purpose of the present invention is to provide a planographic printing plate precursor which suppresses bleeding or transferring of a substance over time while maintaining edge stain preventing performance, a plate-making method of a planographic printing plate, and a printing method using the planographic printing plate. The planographic printing plate precursor includes a support; and an image recording layer formed on the support, in which layer arrangement described in any one of the following i to iv is provided, a hydrophilizatioin agent layer containing a hydrophilization agent is provided in a region in a specific position of the layer arrangement from the end portion of the planographic printing plate precursor to a portion inside the end portion by 1 cm, and the image recording layer includes an infrared absorbing agent and a specific radical polymerizable compound. i: a mode in which the support layer and the image recording layer are provided in this order. ii: a mode in which the support layer, an undercoat, and the image recording layer are provided in this order. iii: a mode in which the support layer, the image recording layer, and a protective layer are provided in this order. iv: a mode in which the support layer, the undercoat, the image recording layer, and the protective layer are provided in this order.

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 including a support and a coating comprising a polymerisable compound, optionally a sensitizer, a photoinitiator and discrete particles is disclosed wherein the discrete particles comprise a crosslinked hydrophobic polymer backbone and a plurality of hydrophobic pendant grafts.

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.

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-accepting polymerization initiator, and a polymerizable compound, LUMO of the electron-accepting polymerization initiator-LUMO of the infrared absorber is 0.45 eV or more, and the outermost layer contains a discoloring compound. Also provided is 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 planographic printing plate precursor containing in the following order: an aluminum support; an image recording layer; and a protective layer, in which a thickness of the protective layer is 0.2 μm or greater, and in a case where a Bekk smoothness of a surface of an outermost layer at a side where the image recording layer is provided is 1000 seconds or less.

A lithographic printing plate precursor is disclosed including a support and a coating comprising (i) a photopolymerisable layer including a polymerisable compound and a photoinitiator, and a top layer provided above the photopolymerisable layer; characterized in that the top layer includes a non-polymeric polyfunctional compound in an amount between 2 mg/m.sup.2 and 80 mg/m.sup.2 which comprises at least two carboxyl and/or carboxylate groups.