A laser-engravable pad printing plate comprising at least (a) a metal support, (b) an adhesion layer, (c) a laser-engravable recording layer having a layer thickness of 20 m to 200 m, (d) a cover film,
characterized in that the laser-engravable recording layer (c) comprises (c1) 40 to 95 wt % of a polyvinyl alcohol, (c2) 5 to 50 wt % of an IR absorber, (c3) 0 to 30 wt % of an inorganic filler, (c4) 0 to 20 wt % of a crosslinker, and (c5) 0 to 10 wt % of further additives.

A positive-working lithographic printing plate precursor includes 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 and a binder including a monomeric unit including an oxalylamide moiety and a monomeric unit including a solubility enhancing group.

Provided are an on-machine development-type lithographic printing plate precursor including: an image-recording layer on an aluminum support having an anode oxide film, in which an end portion of the lithographic printing plate precursor has a shear droop shape, the image-recording layer contains a compound having a support adsorptive property, having a molecular weight of 1,000 or less, and not having an unsaturated double bond group in a molecule, and a content of the compound is substantially the same in a plane of the image-recording layer and a method for producing a lithographic printing plate in which the lithographic printing plate precursor is used.

Provided is a positive type lithographic printing plate precursor including at least: a support which has a hydrophilic surface or a hydrophilic layer; and an underlayer, an interlayer, and an upper layer on the support in this order, in which the underlayer contains a polymer compound 1 which has at least one structure selected from the group consisting of a urethane bond, an acetal structure, and a urea bond in a main chain, the interlayer contains a polymer compound 2 which has at least one structure selected from the group consisting of a sulfonamide group, an active imide group, and a urea bond in a side chain, the upper layer contains a polymer compound 3 which has a phenolic hydroxy group, and one or more layers among the underlayer, the interlayer, and the upper layer contain an infrared absorbent. Further, provided are a method of producing the positive type lithographic printing plate precursor and a method of preparing a lithographic printing plate using the positive type lithographic printing plate precursor.

On-press developable, negative-working infrared radiation-sensitive lithographic printing plate precursors have an aluminum-containing substrate having at least inner and outer aluminum oxide layers. A hydrophilic layer is present on the outer aluminum oxide layer at 0.0002-0.1 g/m.sup.2 and contains a phosphorus-containing compound represented by Formula (I) at a coverage of 50-300 mg/m.sup.2. A hydrophilic polymer can also be present at a lower coverage than that of the phosphorus-containing compound. These precursors have an on-press developable, negative-working infrared radiation-sensitive imageable layer having at least a free radically polymerizable component; an initiator composition that provides free radicals upon exposure to imaging infrared radiation; an infrared radiation absorber having an anionic chromophore; and optionally a polymeric binder that is different from all other components. Such precursors can be imaged and on-press developed to provide lithographic printing plates, and they can be readily manufactured using a particular sequence of steps including multiple anodization steps.

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 are a lithographic printing plate precursor including an aluminum support, and an image recording layer on the aluminum support, in which the aluminum support includes an anodized film on a surface of the image recording layer side, the anodized film has micropores extending in a depth direction from the surface of the anodized film on the image recording layer side, an average pore diameter of the micropores in the surface of the anodized film is greater than 0 m and 0.03 m or less, an average maximum diameter of the micropores inside the anodized film is in a range of 0.04 m to 0.30 m, an average value A nm of thicknesses of surface opening portions and an average value B nm of thicknesses of internal maximum diameter portions satisfy a relationship of 2.5B/A28.0, and the image recording layer contains an acid color former; a method of preparing a lithographic printing plate using the lithographic printing plate precursor; and a lithographic printing method.

Disclosed is a heat-sensitive processless planographic printing plate material containing a thermosensitive protection layer. The planographic printing plate material sequentially comprises a supporting body, a hydrophilic layer, a heat-sensitive layer and a thermosensitive protection layer from the bottom up. The thermosensitive protection layer therein can not only isolate oxygen and protect the heat-sensitive layer from oxygen inhibition, but can also sense heat and allow a polymerization reaction to take place. Thus the binding force between same and the next layer is improved, so that the precision of printing plate images is high, the development performance is good, and the pressrun is high.

Provided are a lithographic printing plate precursor including an aluminum support, and an image recording layer on the aluminum support, in which the aluminum support includes an anodized film on a surface of the image recording layer side, the anodized film has micropores extending in a depth direction from the surface of the anodized film on the image recording layer side, an average pore diameter of the micropores in the surface of the anodized film is greater than 0 m and 0.03 m or less, an average maximum diameter of the micropores inside the anodized film is in a range of 0.04 m to 0.30 m, an average value A nm of thicknesses of surface opening portions and an average value B nm of thicknesses of internal maximum diameter portions satisfy a relationship of 2.5B/A28.0, and the image recording layer contains an acid color former; a method of preparing a lithographic printing plate using the lithographic printing plate precursor; and a lithographic printing method.

Provided is a positive type lithographic printing plate precursor including at least: a support which has a hydrophilic surface or a hydrophilic layer; and an underlayer, an interlayer, and an upper layer on the support in this order, in which the underlayer contains a polymer compound 1 which has at least one structure selected from the group consisting of a urethane bond, an acetal structure, and a urea bond in a main chain, the interlayer contains a polymer compound 2 which has at least one structure selected from the group consisting of a sulfonamide group, an active imide group, and a urea bond in a side chain, the upper layer contains a polymer compound 3 which has a phenolic hydroxy group, and one or more layers among the underlayer, the interlayer, and the upper layer contain an infrared absorbent. Further, provided are a method of producing the positive type lithographic printing plate precursor and a method of preparing a lithographic printing plate using the positive type lithographic printing plate precursor.