| 摘要 |
A method whereby a coating layer is formed on an outer surface of a cylindrical substrate by dipping the cylindrical substrate in a coating solution containing dissolved material, and vertically removing the cylindrical substrate from the coating solution. The lower end portion of the substrate which has a thick portion as a sag formed by a run of the coating solution on the outer surface of the substrate is brought into contact with a tapered outer surface of a member having said tapered outer surface immediately after the substrate is removed from the coating solution. Thus, the thick portion is transferred from the lower end of the substrate to the tapered surface. Then, a solvent of the dissolved material is sprayed to an inner wall surface of the substrate while a gap is formed between the lower end of the substrate and the tapered surface, thereby removing the material from a lower end face and the inner wall surface of the substrate. A sag removing apparatus comprises a member having a tapered outer surface with a rotatable spray nozzle for spraying the inner wall of the substrate with a solvent.
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