| 摘要 |
PURPOSE:To uniformize the thickness of a film, in forming the film to a discoid recording medium, by using a roller coater having a coating roller of which the peripheral length is not smaller than the diameter of the recording medium. CONSTITUTION:In forming a hot melt adhesive film or a hard coat film to an optical magnetic disk, the diameter alpha of a coating roller is set with respect to the outer diameter D of a discoid recording medium so as to obtain the relation of pialpha>D in order to form a uniform film. For example, in the case of a doughnut-shaped substrate having an outer diameter of 200mmphi, if a roll coater having a roller diameter of 100mmphi is used and a doctor knife 3 is adjusted to apply a rubbery hot melt adhesive so as to obtain a film thickness of 50mum, a film having a uniform thickness can be formed on the substrate 7.
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