Coating method and apparatus
AssigneeFuji Photo Film Co., Ltd.
InventorToru Yoshida
Life of this patent
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Abstract
A slide bead coating method and apparatus for applying a coating solution onto an advancing web includes an air compressed chamber for keeping a lower side of a solution bead in a pressure-applied condition to produce a difference in pressure between the upper side and the lower side of the solution bead to stabilize the bead. A coating solution which has a low viscosity and good wetting properties can thus be applied onto the web at high speeds and in a thin layer form, and a so-called bead-dropping phenomenon is avoided. Therefore, the preparation of a layer for photo-sensitive materials is facilitated.
Claims9
The method of coating an advancing web, comprising the steps of:
- feeding a coating solution having a viscosity of no more than 2 cp and a surface tension not greater than 25 dyne/cm from a die block to a surface of a web so that a coating solution bead is formed between said die block and said web;
- advancing said web past said solution bead so that said web travels from a lower side of said solution bead to an upper side of said solution bead;
- and
- applying pressure to said lower side of said solution bead to create a positive pressure differential between said lower side and said upper side of said solution bead to support and stabilize said solution bead.
An apparatus for applying a coating solution onto a surface of a web, comprising:
- a first die block;
- a roll for advancing said web past an edge of said first side block, said web surface being spaced apart from said die block edge;
- means for pumping said coating solution onto said die block edge to form a solution bead between said web surface and said die block edge, said web surface being transported by said roll from a lower side of said solution bead to a upper side of said solution bead;
- and
- means for creating a positive pressure differential between said lower side and said upper side of said solution bead.
Dependencies are inferred from the claim text.