The present invention provides a printing plate precursor, a method of producing a printing plate, and a printing method with excellent stain resistance and deinking capability after being left to stand at the time of obtaining a printing plate. The printing plate precursor of the present invention is a printing plate precursor including an aluminum support, and a functional layer which is disposed on the aluminum support, in which the aluminum support includes an aluminum plate and an aluminum anodized film disposed on the aluminum plate, the anodized film is positioned closer to the functional layer than the aluminum plate is, the anodized film has micropores extending in a depth direction from a surface of the functional layer side, and an average diameter of the micropores in the surface of the anodized film is in a range of 13 nm to 100 nm, the printing plate precursor contains a hydrophilizing agent in a region on a plate surface of the functional layer side which extends to a distance of 5 mm inward from two facing end portions of the printing plate precursor, and a content of the hydrophilizing agent per unit area in the region is greater than a content of the hydrophilizing agent per unit area in a region other than the region by 10 mg/m.sup.2 or greater.

Provided is a method for production of an aluminium strip for lithographic printing plate supports from an aluminium alloy including (in wt %): 0.05%Si0.25%, 0.2%Fe1%, Cu max. 400 ppm, Mn0.30%, 0.10%Mg0.50%, Cr100 ppm, Zn500 ppm, Ti<0.030%, the remainder aluminium and unavoidable impurities individually at most 0.03%, in total at most 0.15%. In the method, a rolling ingot is cast from an aluminium alloy, and the rolling ingot is homogenised. Further, the rolling ingot is hot rolled to a hot strip final thickness, and the hot strip is cold rolled to final thickness of between 0.1 mm and 0.5 mm. The product of the relative final thicknesses of the aluminium strip after the first and after the second cold rolling pass of the aluminium strip is 15% to 24%.

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.

An on-press development type lithographic printing plate precursor including an aluminum support having an anodized film and an image-recording layer provided on the support, a shear droop shape in which an amount X of shear droop is from 25 to 150 m and a width Y of shear droop is from 70 to 300 m is provided on an edge portion of the lithographic printing plate precursor, and an area ratio of cracks present on a surface of the anodized film in a region corresponding to the width of shear droop Y of the lithographic printing plate precursor is 30% or less, and a method for producing a lithographic printing plate using the on-press development type lithographic printing plate precursor are provided.

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 m to 20 m; 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 are a lithographic printing plate precursor having an image-recording layer on a hydrophilic support, in which the image-recording layer includes an organic polymer particle, and the organic polymer particle is a reaction product obtained by at least reacting an aromatic polyvalent isocyanate compound having a structure represented by Formula PO and water, a method for making a lithographic printing plate having excellent printing resistance in the case of using an ultraviolet-curable ink in printing, a new organic polymer particle, and a resin composition including the organic polymer particle.

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Described herein is a continuous coil pretreatment process used to treat the surface of an aluminum alloy sheet or coil for subsequent deposition of an acidic organophosphorus compound. The process can include applying a cleaner to a surface of an aluminum sheet or a coil; etching the surface of the aluminum sheet or the coil with an acidic solution; rinsing the surface of the aluminum sheet or the coil with deionized water; applying to the surface of the aluminum sheet or the coil a solution of an acidic organophosphorus compound; rinsing the surface of the aluminum sheet or the coil with deionized water; and drying the surface of the aluminum sheet or the coil.

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.

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.

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.