Patent application number | Description | Published |
20110277508 | MANUFACTURING METHOD OF GLASS BLANK FOR MAGNETIC RECORDING GLASS SUBSTRATE, MANUFACTURING METHOD OF MAGNETIC RECORDING GLASS SUBSTRATE AND MANUFACTURING METHOD OF MAGNETIC RECORDING MEDIUM - Provided is a method of manufacturing a glass blank for a magnetic recording medium glass substrate, including: manufacturing a glass blank by at least press molding a falling molten glass gob with a pair of press molds both so as to face each other in a direction perpendicular to a direction in which the molten glass gob falls, in which: the molten glass gob is formed of a glass material having a glass transition temperature of 600° C. or more; and when the press molding is carried out so that the molten glass gob is completely extended by pressure and molded into a flat glass between press-molding surfaces of the pair of press molds, at least a region in contact with the flat glass in each of the press-molding surfaces of the pair of press molds forms a substantially flat surface. Also provided are a method of manufacturing a magnetic recording medium glass substrate and a method of manufacturing a magnetic recording medium each using the method of manufacturing a glass blank for a magnetic recording medium glass substrate. | 11-17-2011 |
20110283739 | METHOD FOR MANUFACTURING GLASS BLANK, METHOD FOR MANUFACTURING MAGNETIC RECORDING MEDIUM SUBSTRATE AND METHOD FOR MANUFACTURING MAGNETIC RECORDING MEDIUM - Provided are a method of manufacturing a glass blank, the method including press-molding a molten glass gob under a state in which a separation mark formed on an upper surface of the molten glass gob faces at least one of the molding surface sides of a pair of press molds arranged facing each other in a horizontal direction, when the molten glass gob falls into a space between the pair of press molds, and a method of manufacturing a magnetic recording medium substrate and a method of manufacturing a magnetic recording medium, both using the glass blank. | 11-24-2011 |
20120247155 | METHOD OF MANUFACTURING GLASS BLANK FOR MAGNETIC RECORDING MEDIUM GLASS SUBSTRATE, METHOD OF MANUFACTURING MAGNETIC RECORDING MEDIUM GLASS SUBSTRATE, METHOD OF MANUFACTURING MAGNETIC RECORDING MEDIUM, AND APPARATUS FOR MANUFACTURING GLASS BLANK FOR MAGNETIC RECORDING MEDIUM GLASS SUBSTRATE - A method of manufacturing a glass blank for a magnetic recording medium glass substrate in which, after a pair of press molds placed so as to be opposed to each other in a horizontal direction with press-molding surfaces thereof and the temperatures of the press-molding surfaces being substantially the same are brought into contact with a molten glass gob substantially at the same time, press molding is carried out to produce plate glass and the plate glass continues to be pressed with the pair of molds, and then, when the plate glass is taken out, the duration time of pressing the plate glass is controlled so that the flatness of the glass blank is 10 μm or less, and a method of manufacturing a magnetic recording medium glass substrate, a method of manufacturing a magnetic recording medium, and an apparatus for manufacturing a glass blank for a magnetic recording medium glass substrate using the same. | 10-04-2012 |
20130074550 | MANUFACTURING METHOD OF A SHEET GLASS MATERIAL FOR MAGNETIC DISK AND MANUFACTURING METHOD OF A GLASS SUBSTRATE FOR MAGNETIC DISK - A manufacturing method of a sheet glass material for magnetic disk, the method includes, dropping process for dropping a lump of molten glass; pressing process for sandwiching simultaneously the lump from both sides of the dropping path of the lump with surfaces of a pair of dies facing together, and performing press forming to the lump to obtain a sheet glass material, wherein at least one of the pair of dies has a convex shape with respect to the dropping path of the lump. | 03-28-2013 |
20130086945 | MANUFACTURING METHOD OF A SHEET GLASS MATERIAL FOR MAGNETIC DISK AND MANUFACTURING METHOD OF A GLASS SUBSTRATE FOR MAGNETIC DISK - A manufacturing method of a sheet glass material for magnetic disk, the method includes, dropping process for dropping a lump of molten glass; pressing process for sandwiching simultaneously the lump from both sides of the dropping path of the lump with surfaces of a pair of dies facing together, and performing press forming to the lump to obtain a sheet glass material, wherein at least one of the pair of dies has a concave shape with respect to the dropping path of the lump. | 04-11-2013 |
20130316194 | MANUFACTURING METHOD OF GLASS BLANK FOR MAGNETIC DISK, MANUFACTURING METHOD OF GLASS SUBSTRATE FOR MAGNETIC DISK, GLASS BLANK FOR MAGNETIC DISK, GLASS SUBSTRATE FOR MAGNETIC DISK, AND MAGNETIC DISK - To provide a method for manufacturing a glass blank for magnetic disk and a method for manufacturing a glass substrate for magnetic disk, which are capable of producing a glass blank for magnetic disk having a good surface waviness by press forming, and a method for manufacturing a glass substrate for magnetic disk. A method for manufacturing a glass blank for magnetic disk, which includes a forming process of press-forming a lump of molten glass using a pair of dies, wherein in the forming process, press forming is performed using thermally equalizing means for reducing a difference in temperature in the press forming surface of the die during pressing of the molten glass. | 11-28-2013 |
20140050912 | GLASS SUBSTRATE FOR MAGNETIC DISK AND METHOD FOR MANUFACTURING GLASS SUBSTRATE FOR MAGNETIC DISK - A method for manufacturing a glass substrate for magnetic disk is provided. The method includes a forming process of press-forming a lump of molten glass using a pair of dies, wherein in the forming process, the cooling rate of the molten glass during pressing is controlled so that a first compressive stress layer is formed on a pair of principal faces of a glass blank that is press formed, and the method includes a chemically strengthening process for forming a second compressive stress layer on a pair of principal faces of a glass substrate formed using the glass blank after the forming process. | 02-20-2014 |
20140060117 | METHOD FOR MANUFACTURING GLASS SUBSTRATE FOR MAGNETIC DISK - A method for manufacturing a glass substrate for magnetic disk, the internal strain of which is reduced without performing annealing treatment, is provided. The method includes a forming process of forming a plate-shaped glass blank by pressing a lump of molten glass using a pair of dies, wherein the method includes: a removing process of removing at least a part of a residual stress layer formed on the principal face of the glass blank press-formed in the forming process; and a process of forming a donut-shaped glass substrate by subjecting the glass blank after the removing process to machining. | 03-06-2014 |
20140065446 | METHOD FOR MANUFACTURING GLASS BLANK FOR MAGNETIC DISK, METHOD FOR MANUFACTURING GLASS SUBSTRATE FOR MAGNETIC DISK, GLASS BLANK FOR MAGNETIC DISK - A method for manufacturing a glass blank for magnetic disk and a method for manufacturing a glass substrate for magnetic disk are provided which are capable of producing a glass blank for magnetic disk having a good surface waviness by press forming. The method includes a forming process of press-forming a lump of molten glass using a pair of dies, wherein in the forming process, press forming is performed using thermally equalizing means for reducing a difference in temperature in the press forming surface of the die during pressing of the molten glass. | 03-06-2014 |