Patent ID: 8118951

Claim:
An aluminum alloy sheet for a lithographic printing plate, said aluminum alloy sheet being produced by cold-rolling a hot-rolled product without performing process annealing and comprising 0.03 to 0.15 mass % of Si, 0.2 to 0.7 mass % of Fe, 0.05 to 0.5 mass % of Mg, 0.003 to 0.05 mass % 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 μm 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 μm from the surface of the aluminum alloy sheet, the % being mass %.