Aluminum alloy blank for lithographic printing plate and support for lithographic printing plate

1. An aluminum alloy blank for a lithographic printing plate made of a continuously cast flat-rolled aluminum alloy plate, the aluminum alloy blank for a lithographic printing plate comprising:

iron in a range of 0.20 to 0.80 wt %; and

the balance being aluminum, up to 0.05 wt % of titanium and/or up to 0.02 wt % of boron as a crystal grain refining element, and unavoidable impurity elements,

wherein, the unavoidable impurity elements comprise silicone and copper, a content of silicon is in a range of 0.02 to 0.30 wt %, and a content of copper is equal to or below 0.05 wt %, and

a solid solution amount of silicon is in a range of 150 ppm to 1500 ppm and a solution amount of iron is in a range of 300 ppm to 1300 ppm.

2. The aluminum alloy blank for a lithographic printing plate according to claim 1 ,

wherein the blank has a resistivity as measured at liquid nitrogen temperature in a range of 6.5 to 3.5 μΩmm.

3. A support for a lithographic printing plate,

wherein the support for a lithographic printing plate is formed by performing a surface roughening treatment including an electrochemical surface roughening on an aluminum alloy blank for a lithographic printing plate according to claim 1 .

4. The support for a lithographic printing plate according to claim 3 ,

wherein the surface roughening treatment including the electrochemical surface roughening comprises the processes of:

performing a first electrochemical surface roughening treatment using a total quantity of electricity in a range of 65 to 500 C/dm 2 upon an anodic reaction in the electrolytic solution containing nitric acid;

alkaline etching not less than 0.1 g/m 2 of aluminum;

performing a second electrochemical surface roughening treatment using a total quantity of electricity in a range of 25 to 100 C/dm 2 upon an anodic reaction in the electrolytic solution containing hydrochloric acid; and

alkaline etching not less than 0.03 g/m 2 of aluminum.

5. The aluminum alloy blank for a lithographic printing plate according to claim 1 ,

wherein aluminum alloy blank for a lithographic printing plate is formed by the step comprising an intermediate annealing at 300° C. to 600° C. for 5 to 20 hours.

6. A presensitized plate comprising:

a recording layer on one surface of a support for a lithographic printing plate according to claim 3 .

7. A presensitized plate comprising:

a recording layer on one surface of a support for a lithographic printing plate according to claim 3 ; and

a woodgrain pattern or a stripe pattern on the other surface thereof.