PURPOSE: To suppress the stripe trouble and thick or thin coating trouble generated in a coating start part and a splice part by supplying gas to a web so that the average collision speed to the web of the gas and the running speed of the web satisfy a specific condition.
CONSTITUTION: A substitution chamber 12 is provided on the upstream side of the liquid contact part of coating solns S1, S2 flowing down in a curtain like state and a web 1 and carbon dioxide is supplied as gas high in the solubility to the coating solns S1, S2 from a gas supply source 13 and ejected to the web 1 from the slit 12a formed over the entire width region of the web to substitute the air accompanied by the web 1 with carbon dioxide. At this time, by adjusting the gap of the discharge slit 12a or the supply amt. of the soluble gas so that the average speed thereof satisfies formula, the accompanied air is perfectly substituted with the gas high in the solublility to the coating solns S1, S2. In the formula, V is the average collision speed to the web 1 of the gas and Cs is the running speed m/sec of the web 1.
SAITO ATSUSHI
NISHIWAKI AKIRA
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