METHOD OF MANUFACTURING GLASS BLANK FOR MAGNETIC RECORDING MEDIUM GLASS SUBSTRATE, MAGNETIC RECORDING MEDIUM GLASS SUBSTRATE MANUFACTURING METHOD, MAGNETIC RECORDING MEDIUM MANUFACTURING METHOD, AND DEVICE FOR MANUFACTURING GLASS BLANK FOR MAGNETIC RECORDING MEDIUM GLASS SUBSTRATE

摘要

To achieve improvement in evenness, provided are a method of manufacturing a glass blank for a magnetic recording medium glass substrate, and a magnetic recording medium glass substrate manufacturing method, a magnetic recording medium recording method, and a device for manufacturing a glass blank for a magnetic recording medium glass substrate, which employ said method of manufacturing a glass blank for a magnetic recording medium glass substrate, wherein: a pair of press-forming molds, which are positioned in opposition in the horizontal direction upon a piece of molten glass, and having effectively identical press-forming faces and press-forming face temperatures, are brought into approximately simultaneous contact with the piece of molten glass, press-forming same, producing a glass sheet; and the continuous time of the pressing of the glass sheet is controlled such that, upon extracting the glass sheet after sustained pressing thereof by the pair of molds, the evenness of the glass blank is 10μm or less.