IR-sensitive lithographic printing plate precursors provide a stable printout using a unique IR-sensitive image-recording layer. The IR radiation-sensitive layer includes: component (1) a free radical initiator composition; component (2) a free radically polymerizable composition; and component (3) a color-changing compound of Structure (I) having an indene structure in the conjugated chain between the aromatic terminal groups. A specific group, such as a halo group, is directly or indirectly attached to this indene structure. The infrared radiation-sensitive image-recording composition and layer also contains one or more borate ions. After infrared imaging, these precursors exhibit desirable fresh or initial printout and printout after dark storage. The precursors can be developed on-press.

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.

Provided are a curable composition including a sail compound having a) an organic anion in which, in Hansen, solubility parameter, d is 16 or more, p is 16 or more and 32 or less, and H is 60% or less of p 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.

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 toplayer provided above the photopolymerisable layer;characterized in that the toplayer includes a hydrophobic binder, and hydrophobic discrete particles having a melting and/or softening temperature above 50? C.

A method for producing a lithographic printing plate includes, in this order, a step of preparing a lithographic printing plate precursor having an image-recording layer on a hydrophilic support, a step of exposing the lithographic printing plate precursor in an image shape, and a step of removing a non-exposed portion of the image-recording layer exposed in the lithographic printing plate precursor using a developer, the developer includes a compound having at least one acidic group selected from the group consisting of a phosphate group, a phosphonate group, and a phosphinate group and one or more carboxy groups, a pH of the developer is 5 to 10, and, after the removal step, a step of washing a surface of an obtained lithographic printing plate with water and a step of desensitizing the surface of the obtained lithographic printing plate are not provided.

Lithographic printing plate precursors are prepared with a unique aluminum-containing substrate prepared using two separate anodizing processes to provide an inner aluminum oxide layer of average dry thickness (T.sub.i) of 300-3,000 nm and a multiplicity of inner micropores of average inner micropore diameter (D.sub.i) of ?100 nm. An outer aluminum oxide layer is also provided to have a multiplicity of outer micropores of average outer micropore diameter (D.sub.o) of 15-30 nm and a dry thickness (T.sub.o) of 30-650 nm. A hydrophilic layer disposed on the outer aluminum oxide layer at 0.0002-0.1 g/m.sup.2 has at least a hydrophilic copolymer composed of (a) recurring units having an amide group and (b) recurring units comprising an OM group directly connected to a phosphorus atom, wherein M represents a hydrogen, sodium, potassium, or aluminum atom.

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.

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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.

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.