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.

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.

On-press developable, negative-working lithographic printing plate precursors are used to provide lithographic printing plates. Such precursors are prepared with a substrate and one or more negative-working, infrared radiation-sensitive imagable layers. The substrate is prepared by two separate anodizing processes to provide an inner aluminum oxide layer having an average dry thickness (T.sub.i) of 650-3,000 nm and inner micropores having an average inner micropore diameter (D.sub.i) of <15 nm. A formed outer aluminum oxide layer comprises outer micropores having an average outer micropore diameter (D.sub.o) of 15-30 nm; an average dry thickness (T.sub.o) of 130-650 nm; and a micropore density (C.sub.o) of 500-3,000 micropores/m.sup.2. The ratio of D.sub.o to D.sub.i is greater than 1.1:1, and D.sub.o in nanometers and the outer aluminum oxide layer micropore density (C.sub.o) in micropores/m.sup.2, are further defined by the outer aluminum oxide layer porosity (P.sub.o) as:
0.3P.sub.o0.8
wherein P.sub.o is 3.14(C.sub.o)(D.sub.o.sup.2)/4,000,000.

Provided are 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 or in which Expression (1) and Expression (2) are satisfied in a case where a Bekk smoothness of a surface of an outermost layer on a side where the image recording layer is provided is set as a seconds and a Bekk smoothness of a surface of an outermost layer on a side opposite to a side where the image recording layer is provided is set as b seconds; a method of producing the same; 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.

a1000,b1000(1)

1/a+1/b0.002(2)

The present invention aims at providing a lithographic printing plate precursor, a lithographic printing plate manufacturing method, a printing method and an aluminum support manufacturing method that enable the resulting lithographic printing plate to have a long tiny dot press life. The lithographic printing plate precursor of the invention is a lithographic printing plate precursor having an aluminum support and an image recording layer disposed above the aluminum support. When measured over a 400 m400 m region of a surface of the aluminum support on the image recording layer side using a three-dimensional non-contact roughness tester, pits with a depth from centerline of at least 0.70 m are present at a density of at least 3,000 pits/mm.sup.2; and a surface area ratio S is not less than 35%, the surface area ratio S being determined using an actual area S.sub.x obtained, through three-point approximation, from three-dimensional data acquired by measurement at 512512 points in 25 m square of the surface of the aluminum support on the image recording layer side by means of an atomic force microscope and a geometrically measured area S.sub.o.

An object of the invention is to provide an aluminum support for a planographic printing plate and a planographic printing plate precursor which can be used to obtain a plate precursor for a planographic printing plate that is excellent in terms of plate wear resistance in the case of being used to produce a planographic printing plate and exhibits excellent on-machine developability. In an aluminum support for a planographic printing plate of the embodiment of the invention, an average value of surface area-increase rates S.sub.SEM (%) is 200% or more, and an average value of pit depths h.sub.SEM (nm) is 400 nm or less.

The present invention provides a lithographic printing plate precursor that enables a lithographic printing plate formed therefrom to have excellent image visibility and a long press life, as well as a lithographic printing plate manufacturing method and a printing method. The lithographic printing plate precursor of the invention is a lithographic printing plate precursor including an aluminum support and an image recording layer, the aluminum support includes an aluminum plate and an anodized film of aluminum formed on the aluminum plate, the anodized film is positioned closer to the image recording layer than the aluminum plate is, the anodized film has micropores extending in a depth direction of the anodized film from a surface of the anodized film on the image recording layer, the micropores have an average diameter of more than 10 nm but not more than 100 nm at the surface of the anodized film, and the surface of the anodized film on the image recording layer side has a lightness L* of 70 to 100 in a L*a*b* color system.

On-press developable, negative-working lithographic printing plate precursors are used to provide lithographic printing plates. Such precursors are prepared with a substrate and one or more negative-working, infrared radiation-sensitive imagable layers. The substrate is prepared by two separate anodizing processes to provide an inner aluminum oxide layer having an average dry thickness (T.sub.i) of 650-3,000 nm and inner micropores having an average inner micropore diameter (D.sub.i) of <15 nm. A formed outer aluminum oxide layer comprises outer micropores having an average outer micropore diameter (D.sub.o) of 15-30 nm; an average dry thickness (T.sub.o) of 130-650 nm; and a micropore density (C.sub.o) of 500-3,000 micropores/m.sup.2. The ratio of D.sub.o to D.sub.i is greater than 1.1:1, and D.sub.o in nanometers and the outer aluminum oxide layer micropore density (C.sub.o) in micropores/m.sup.2, are further defined by the outer aluminum oxide layer porosity (P.sub.o) as:

0.3P.sub.o0.8

wherein P.sub.o is 3.14(C.sub.o)(D.sub.o.sup.2)/4,000,000.