PRODUCTION OF SUBSTRATE FOR OPTICAL RECORDING MEDIUM

PROBLEM TO BE SOLVED: To prevent second stamping so as to decrease defective sectors and to enhance reliability by injecting an ionizing gas at the time of parting a molded substrate by opening molds. SOLUTION: A resin is introduced via a sprue into the cavity 6 interposed between the moving side 1 and stationary side 3 of the molds in the case of the production of the substrate by injection molding or injection compression molding. The ionizing gas is injected from the gas inflow sections disposed on the moving side 1 and the stationary side 3 when the substrate is parted after the molding. The injection of the ionizing gas is executed on at least the recording side of the substrate and more preferably on both sides. The ionizing gas ionizes air or gas, such as nitrogen, by an electric field. As a result, the electrification of the substrate simultaneously with parting of a stamper 7 and the substrate is suppressed and the second stamping of readhesion to the stamper 7 by the electrification is prevented. As a result, the occurrence of disturbance in pit shapes is prevented and the complete transfer of the pits of the recording surface to the substrate is made possible.