Aluminum alloy sheet for lithographic printing plate and method of producing the same

Abstract

The invention claims an aluminum alloy sheet for a lithographic printing plate, which is manufactured by refined hot rolling without intermediate annealing and then by cold rolling to obtain ultimate thickness, in which a Pb is concentrated to a surface layer portion and generation of a recess is uniform while electrolysis treatment and which generates no stripes when processing as a printing plate, the invention is characterized by 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, and byhaving an average recrystallized grain diameter of 50 mum or less in the surface layer portion n a direction perpendicular to a rolling direction, and having a Pb concentration 100 to 400 times an average Pb concentration in the surface layer portion up to a depth of 0.2 mum from the surface.

Description

technical field [0001] The present invention relates to an aluminum alloy plate for lithographic printing plates, in particular to an aluminum alloy plate for lithographic printing plates which is suitable for surface roughening by electrochemical etching and has excellent production efficiency during manufacture and a manufacturing method thereof. Background technique [0002] As a support for lithographic printing plates (including offset printing plates), an aluminum alloy plate is generally used. From the viewpoint of improving the adhesion of the photosensitive film and improving the water retention of the non-image area, the surface of the support is roughened, but in recent years In the past, due to the excellent plate-making adaptability or printing performance, and the possibility of continuous processing in the coil, etc., the method of roughening the surface of the aluminum alloy plate for the support by electrochemical etching has been rapidly developed. [0003]...

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Problems solved by technology

[0004] Conventionally, these aluminum alloy materials for lithographic printing plates have been subjected to homogenization treatment of ingots, hot rolling, cold rolling, and intermediate annealing in the middle of cold rolling to form a recrystallized structure on the surface of the rolled sheet. Secondary cold rolling, thereby making the generation of pits uniform during electrochemical etching treatment, and preventing the occurrence of streaks when processing as a printing plate, but performing intermediate annealing inevitably brings about a reduction in production efficiency and a decrease in manufacturing costs. increase, hope to improve

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