A photosensitive resin composition contains a polymer compound having a linking group represented by Formula A-1 in the main chain; and an infrared absorbing material. In Formula A-1, R.sup.1 and R.sup.2 each independently represent a hydrogen atom or a monovalent organic group, and X.sup.1 is a specific linking group. ##STR00001##

A lithographic printing plate precursor including an image recording layer on a hydrophilic support, in which the image recording layer includes a polymerization initiator, an infrared absorbent, a polymerizable compound, and an acid color former, and the infrared absorbent includes a compound represented by Formula 1, as well as a method of preparing a lithographic printing plate by use of the lithographic printing plate precursor. In Formula 1, at least one of Ar.sub.1 or Ar.sub.2 has a group represented by the following Formula 2.

XFormula 2

X represents a halogen atom, C(O)X.sub.2R.sub.11, C(O)NR.sub.12R.sub.13, OC(O)R.sub.14, CN, SO.sub.2N.sub.15R.sub.16, or a perfluoroalkyl group, X.sub.2 represents a single bond or an oxygen atom, R.sub.11 and R.sub.14 each independently represent an alkyl group or an aryl group, and R.sub.12, R.sub.13, R.sub.15 and R.sub.16 each independently represent a hydrogen atom, an alkyl group, or an aryl group.

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A flexo-platemaker uses two illumination subsystems with a different resolution for creating a flexographic print master. Optionally, two different curable liquids are used.

A negative type photosensitive resin composition includes a polymer compound which has, in a main chain thereof, a constitutional unit A represented by Formula A-1, a constitutional unit B that is at least one of constitutional units represented by Formulae B-1, B-2, B-3, B-4, B-5, B-6, or B-7, and a constitutional unit C containing an ethylenically unsaturated group; and a polymerization initiator. A negative type planographic printing plate precursor includes an image recording layer containing the negative type photosensitive resin composition. A method of preparing a planographic printing plate includes, in order, an exposure step of image-exposing the negative type planographic printing plate precursor; and a development step of performing development by removing a non-exposed portion of the exposed negative type planographic printing plate precursor using a developer. ##STR00001##

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 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.

There are provided a washout processor and a washing method that prevent solid contents from being attached to a developed flexographic printing plate precursor again. A washout processor that develops an imagewise exposed flexographic printing plate precursor using a washing solution includes a developing tank that is filled with the washing solution, a development unit that performs the development by removing a non-exposed portion of the flexographic printing plate precursor using the washing solution in the developing tank, and a flow creation unit that flows the washing solution in at least one region of a first region where the flexographic printing plate precursor is carried into the washing solution of the developing tank or a second region where the flexographic printing plate precursor is carried out from the washing solution of the developing tank, in an intersecting direction to cross a width of the flexographic printing plate precursor with respect to a traveling direction of the flexographic printing plate precursor.