PURPOSE: To prevent curving of an Al web and formation of flaws on the rear surface thereof by using nozzles for water slurry disposed in a specific direction in the stage of roughening the web surface by spraying the water slurry contg. the pulverous powder of a polishing material while moving said web by an endless belt.
CONSTITUTION: An Al web 5 as a base for a lithographic printing plate is continuously run in an arrow direction by traveling of an endless belt 1 in the stage of roughening the one surface of said web by a liquid honing method. Water slurry 8 dispersed therein with the pulverous powder of a polishing material is sprayed from plural nozzles 6 inclined in the advance direction of the web 5. Nozzles 7 for the edge parts of the web 5 where the water slurry from the nozzles 6 does not reach are provided. The intrusion of the water slurry between the web 5 and the belt 1 and the consequent flawing of the rear surface and curving of the web 5 are prevented by the spray of the water slurry from both nozzles 6, 7. The one surface is thus roughened to uniform roughness.
KAKEI TSUTOMU
ODA KAZUTAKA
