Substrate for planographic printing

摘要

A method for preparing a substrate for a planographic printing member is disclosed. A liquid that contains water; a soluble alkali metal silicate, preferably sodium silicate; and a dispersed particulate material is coated on a support, to produce a hydrophilic layer on the support. A layer of image material may be coated over the hydrophilic layer to produce a planographic printing member. In one embodiment the liquid contains a mixture of two particulate materials, preferably alumina and titanium dioxide. The substrate has a surface roughness of about 0.1 mum to 2 mum. The substrate is suitable for preparing a planographic printing member processable to a resolution of 10 mum or less and in which the dots having a roundness of less than 2 are formed.