Lithographic printing plate support and presensitized plate

摘要

A lithographic printing plate support includes an aluminum plate and an anodized film formed at a surface of the aluminum plate and having micropores which extend in a depth direction of the anodized aluminum film from a surface of the anodized film opposite from the aluminum plate. Each of the micropores includes a large-diameter portion and a dendritic small-diameter portion. The lithographic printing plate support has excellent scratch resistance and is capable of obtaining a presensitized plate which exhibits excellent on-press developability and enables a lithographic printing plate formed therefrom to have a long press life and excellent deinking ability after suspended printing.

主权项

1. A lithographic printing plate support comprising: an aluminum plate; and an anodized film formed at a surface of the aluminum plate and having micropores which extend in a depth direction of the anodized film from a surface of the anodized film opposite from the aluminum plate,
wherein each of the micropores has a large-diameter portion which extends to a depth A of 5 to 60 nm from the surface of the anodized film and a dendritic small-diameter portion which communicates with a bottom of the large-diameter portion, and branches off and extends to a depth of 900 to 2,000 nm from a communication position between the small-diameter portion and the large-diameter portion, wherein an aperture average diameter of the large-diameter portion at the surface of the anodized film is from 10 to 100 nm and a ratio of the depth A of the large-sized portion to the aperture average diameter of the large-diameter portion (depth A/aperture average diameter) is from 0.1 to 4.0, wherein a communication position average diameter of the small-diameter portion at the communication position is more than 0 but less than 20 nm, and wherein a ratio of the communication position average diameter of the small-diameter portion to the aperture average diameter of the large-diameter portion (communication position average diameter/aperture average diameter) is up to 0.85.