Lithographic plate

摘要

An Erichsen value of a lithographic plate (1) whose surface has been grained and anodically oxidized is set between 2 and 10, and more preferably between 5 and 6. This prevents the excessive plastic deformation during the machining of the lithographic plate (1), and prevents the formation of cracks in the anodic oxide film resulting from the difference in the rigidity between the aluminum alloy substrate and the anodic oxide film. In addition, the lithographic plate (1) is easy to handle since the cracks, etc. are not formed even if the end of the lithographic plate (1) is bent. <IMAGE>