A method for producing aluminum strips for lithographic printing plate supports, wherein the aluminum strip is produced from a rolling ingot, which after optional homogenizing is hot-rolled to a thickness of 2 mm to 7 mm and cold-rolled to a final thickness of 0.15 mm to 0.5 mm provides for an aluminum strip having a thickness of 0.15 mm to 0.5 mm and a printing plate support produced from the aluminum strip.

Lithographic printing plate precursors have an aluminum-containing substrate prepared using two anodizing processes to provide an inner aluminum oxide layer of average dry thickness of 300-3,000 nm and a multiplicity of inner micropores of average inner micropore diameter of ≤100 nm. An outer aluminum oxide layer is provided with a multiplicity of outer micropores of average outer micropore diameter of 15-30 nm and a dry thickness of 30-650 nm. A hydrophilic layer is disposed on the outer aluminum oxide layer at 0.0002-0.1 g/m.sup.2 and has a (1) compound having an ethylenically unsaturated polymerizable groups; a —OM group connected directly to a phosphorus atom, wherein M represents hydrogen, sodium, potassium, or aluminum; and (2) one or more hydrophilic polymers having (a) recurring units comprising an amide group, and (b) recurring units having an —OM′ group that is directly connected to a phosphorus atom, wherein M′ represents hydrogen, sodium, potassium, or aluminum.

Provided is an on-press development type lithographic printing plate precursor including an aluminum support and an image-recording layer on the aluminum support, in which the image-recording layer contains an infrared absorber, a polymerization initiator, a polymerizable compound, and an addition polymerization-type resin having a hydrophilic structure, a water contact angle on a surface of the aluminum support on a side of the image-recording layer that is determined by an airborne water droplet method is 110° or less, and the polymerizable compound includes a polymerizable compound having 7 or more functional groups. Also provided are a method for preparing a lithographic printing plate and a lithographic printing method using the lithographic printing plate precursor.

A method for producing aluminum strips for lithographic printing plate supports, wherein the aluminum strip is produced from a rolling ingot, which after optional homogenizing is hot-rolled to a thickness of 2 mm to 7 mm and cold-rolled to a final thickness of 0.15 mm to 0.5 mm provides for an aluminum strip having a thickness of 0.15 mm to 0.5 mm and a printing plate support produced from the aluminum strip.

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.

An object of the present invention is to provide a lithographic printing plate precursor from which a lithographic printing plate with excellent oil-based cleaner printing durability is obtained, a method of producing a lithographic printing plate, a printing method, and a method of producing an aluminum support. The lithographic printing plate precursor of the present invention is a lithographic printing plate precursor including an aluminum support, and an image recording layer disposed on the aluminum support, in which the aluminum support includes an aluminum plate and an anodized aluminum film disposed on the aluminum plate, the image recording layer is disposed on the aluminum support on a side of the anodized film, and an area ratio of projections with a height of 0.80 μm or greater from an average level, which is obtained by measuring a surface of the aluminum support on a side of the image recording layer in an area of 400 μm×400 μm using a non-contact three-dimensional roughness meter, is 20% or less.

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.

The present disclosure provides an aluminium alloy strip for lithographic printing plate supports, which has a rolled-in surface topography on one strip surface. Further, a method is disclosed for manufacturing the aluminium alloy strip and a printing plate for lithographic printing, with a printing plate support made of aluminium alloy. The object of proposing an aluminium alloy strip for lithographic printing plate supports is that it provides a long service life in the printing process and is roughened with less charge support entry. This is achieved in that the surface of the aluminium alloy strip has a mean peak number measured perpendicular to the rolling direction of the aluminium alloy strip.

Lithographic printing plate precursors have an aluminum-containing substrate prepared using two anodizing processes to provide an inner aluminum oxide layer of average dry thickness of 300-3,000 nm and a multiplicity of inner micropores of average inner micropore diameter of ≤100 nm. An outer aluminum oxide layer is provided with a multiplicity of outer micropores of average outer micropore diameter of 15-30 nm and a dry thickness of 30-650 nm. A hydrophilic layer is disposed on the outer aluminum oxide layer at 0.0002-0.1 g/m.sup.2 and has a (1) compound having an ethylenically unsaturated polymerizable groups; a —OM group connected directly to a phosphorus atom, wherein M represents hydrogen, sodium, potassium, or aluminum; and (2) one or more hydrophilic polymers having (a) recurring units comprising an amide group, and (b) recurring units having an —OM′ group that is directly connected to a phosphorus atom, wherein M′ represents hydrogen, sodium, potassium, or aluminum.

Provided is a lithographic printing plate precursor having an aluminum support, an image-recording layer, and a water-soluble overcoat layer in this order, in which the image-recording layer contains an infrared-absorbing polymethine colorant having HOMO of −5.2 eV or less, a polymerization initiator, a polymerizable compound, and a polymer, and the polymer has a constitutional unit formed of an aromatic vinyl compound and a constitutional unit formed of an acrylonitrile compound. Also provided are a method for preparing a lithographic printing plate using the lithographic printing plate precursor.