Offset printing plate for printing with wiping water - has covering layer with hydrophobic, hydrophobic and oleophilic components

摘要

The printing plate consists of five layers, a positive plate having a hydrophilic covering layer (1) with a hydrophilic and oleophilic layer (2) underneath, a photoconductor (3), a conductor (4) and a layer carrier (5). The covering layer is changed by development. The component of this layer are so distributed before latent image prodn. and development that the surface of the printing plate is hydrophilic for a positive plate and hydrophilic and oleophilic for a negative plate. A latent electrostatic image can be produced in the covering layer. After exposure and development the exposed areas are hydrophilic and oleophilic for a positive printing plate and hydrophilic and oleophilic for a negative plate. USE/ADVANTAGE - At low mfg. cost allows direct writing with low power laser beam and/or electron beams.