Abstract: An aluminum sheet material for lithographic printing plates wherein the number of aluminum carbide particles having a circle equivalent diameter, measured by the PoDFA method, of 3 ?m or more is four or less, the number of aluminum carbide particles having a circle equivalent diameter, measured by the PoDFA method, of 3 ?m or more.

Abstract: An aluminum alloy sheet for a lithographic printing plate includes 0.03 to 0.15% (mass %, hereinafter the same) of Si, 0.2 to 0.7% of Fe, 0.05 to 0.5% of Mg, 0.003 to 0.05% of Ti, and 30 to 300 ppm of Ga, with the balance being aluminum and inevitable impurities, a surface area of the aluminum alloy sheet having an average recrystallized grain size of 50 ?m or less in a direction perpendicular to a rolling direction, an Mg concentration that is higher than the average Mg concentration by a factor of 5 to 50, and a Ga concentration that is higher than the average Ga concentration by a factor of 2 to 20, the surface area being an area up to a depth of 0.2 ?m from the surface of the aluminum alloy sheet.

Abstract: An aluminum alloy sheet for a lithographic printing plate is obtained by homogenizing an ingot of an aluminum alloy at 500 to 610° C. for one hour or more, the aluminum alloy containing 0.03 to 0.15% of Si, 0.2 to 0.6% of Fe, 0.005 to 0.05% of Ti, and 2 to 30 ppm of Pb, with the balance being aluminum and unavoidable impurities, subjecting the homogenized product to rough hot rolling, a start temperature of the rough hot rolling being 430 to 500° C. and a finish temperature of the rough hot rolling being 400° C. or more, holding the product subjected to rough hot rolling for 60 to 300 seconds after the completion of the rough hot rolling to recrystallize the surface of the product, and subjecting the resulting product to finish hot rolling that is finished at 320 to 370° C.

Abstract: An aluminum alloy sheet for a lithographic printing plate includes 0.03 to 0.15% (mass %, hereinafter the same) of Si, 0.2 to 0.7% of Fe, 0.05 to 0.5% of Mg, 0.003 to 0.05% of 11, and 30 to 300 ppm of Ga, with the balance being aluminum and inevitable impurities, a surface area of the aluminum alloy sheet having an average recrystallized grain size of 50 ?m or less in a direction perpendicular to a rolling direction, an Mg concentration that is higher than the average Mg concentration by a factor of 5 to 50, and a Ga concentration that is higher than the average Ga concentration by a factor of 2 to 20, the surface area being an area up to a depth of 0.2 ?m from the surface of the aluminum alloy sheet.

Abstract: An aluminum sheet material for lithographic printing plates wherein the number of aluminum carbide particles having a circle equivalent diameter measured by the PoDFA method of 3 ?m or more is four or less, the number of aluminum carbide particles having a circle equivalent diameter measured by the PoDFA method of 3 ?m or more being measured by melting 3000 g of the aluminum sheet material in a crucible disposed in an electric furnace, filtering 2000 g of the molten metal through a dedicated filter, allowing 1000 g of the molten metal remaining on the filter to solidify, and measuring the number of aluminum carbide particles contained in inclusions in the molten metal deposited on the upper surface of the filter by observing a vertical section (14 mm×10 mm) of the solidified metal including the diameter (14 mm) of the filter in the center area of the filter up to a height of 10 mm above the filter using a microscope.

Abstract: An aluminum alloy sheet for a lithographic printing plate which allows pits to be more uniformly formed by an electrochemical surface-roughening treatment and exhibits more excellent adhesion to a photosensitive film and water retention properties, and a method of producing the same are disclosed. The aluminum alloy sheet includes 0.1 to 1.5% of Mg, more than 0.05% and 0.5% or less of Zn, 0.1 to 0.6% of Fe, 0.03 to 0.15% of Si, 0.0001 to 0.10% of Cu, and 0.0001 to 0.05% of Ti, with the balance being aluminum and impurities, the Mg content and the Zn content satisfying a relationship “4×Zn %?1.4%?Mg %?4×Zn %+0.6%”, and the amount of aluminum powder on the surface of the aluminum alloy sheet being 0.1 to 3.0 mg/m2. It is more effective when precipitates with a diameter (circle equivalent diameter) of 0.1 to 1.0 ?m are dispersed on the surface of the sheet in a number of 10,000 to 100,000 per square millimeter (mm2).

Abstract: An aluminum alloy sheet for a lithographic printing plate is obtained by homogenizing an ingot of an aluminum alloy at 500 to 610° C. for one hour or more, the aluminum alloy containing 0.03 to 0.15% of Si, 0.2 to 0.6% of Fe, 0.005 to 0.05% of Ti, and 2 to 30 ppm of Pb, with the balance being aluminum and unavoidable impurities, subjecting the homogenized product to rough hot rolling, a start temperature of the rough hot rolling being 430 to 500° C. and a finish temperature of the rough hot rolling being 400° C. or more, holding the product subjected to rough hot rolling for 60 to 300 seconds after the completion of the rough hot rolling to recrystallize the surface of the product, and subjecting the resulting product to finish hot rolling that is finished at 320 to 370° C.

Abstract: A method of producing an aluminum alloy sheet for a lithographic printing plate includes homogenizing an ingot of an aluminum alloy at 500 to 610° C. for one hour or more, the aluminum alloy containing 0.05 to 1.5% of Mg, 0.1 to 0.7% of Fe, 0.03 to 0.15% of Si, 0.0001 to 0.10% of Cu, and 0.0001 to 0.1% of Ti, with the balance being aluminum and unavoidable impurities, subjecting the homogenized product to rough hot rolling, a start temperature of the rough hot rolling being 430 to 500° C. and a finish temperature of the rough hot rolling being 400° C. or more, holding the product subjected to the rough hot rolling for 60 to 300 seconds after completion of the rough hot rolling to recrystallize the surface of the product, subjecting the resulting product to finish hot rolling that is finished at 320 to 370° C.

Abstract: The present invention provides an aluminum alloy sheet for a lithographic printing plate which allows pits to be uniformly formed by electrochemical roughening, and excels in strength and heat softening resistance. The aluminum alloy sheet for a lithographic printing plate includes 0.1-0.3% of Mg, more than 0.05%, but 0.5% or less of Zn, 0.2-0.6% of Fe, 0.03-0.15% of Si, 0.02% or less of Cu, and 0.003-0.05% of Ti, the remainder being Al and impurities. The aluminum alloy sheet may include more than 0.05%, but 0.3% or less of Mn.