Method and apparatus for applying a coating liquid to a moving web
AssigneeFuji Photo Film Co., Ltd.
InventorNaoyuki Kawanishi
Life of this patent
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Abstract
The invention relates to a method and apparatus for treating a moving web prior to the applying of a photosensitive coating liquid. In order to suppress the entrapment of air between the coating layer and the web, the surface of the web is electrostatically charged so that the coating liquid will be attracted to the web. Wide variations of the potential distribution across the web are avoided by subjecting the web to heat while simultaneously bleeding off part of the surface potential. The heating step increases the mobility of electrostatic charge and accelerates the charge redistribution across the web. The web is subsequently cooled to a temperature between 5.degree. and 25.degree. C. in order to preserve the surface potential of the web until the web is coated.
Claims10
A coating method, comprising;
- impressing a electrostatic charge on a surface of a web;
- grounding electrically said web while heating said web such that the temperature thereof reaches between 30.degree. and 100.degree. C., to reduce the surface potential of said web and promote the charge redistribution;
- thereafter cooling the web to a temperature between 5.degree. and 25.degree. C.;
- and
- applying a coating liquid to said web at a coating station.
An apparatus for processing and coating a web;
- comprising;
- means for impressing a DC voltage upon a surface of said web,
- heating means for heating said web to a temperature between 30.degree. and 100.degree. C.,
- means for bleeding off a part of the charge located within said heating means, for substantially reducing the surface potential of said web,
- means for cooling said web to a temperature between 5.degree. and 25.degree. C., and
- coating means for applying a coating liquid to said web.
Dependencies are inferred from the claim text.