| 摘要 |
In the case where multiple slide hopper is used for simultaneous multilayer bead coating of photosensitive material, streak defect is occasionally cause, particularly in the case of coating photothermographic material, especially when the outermost layer includes materials capable of increasing optical density such as toner it more frequently happens. It is found that streak defect is restrained when meniscus curvature of upper side bead becomes less than 7.2 mm-1. This condition can be kept by selecting a proper value of clearance between the web surface and the lip of the slide hopper, that is from 0.10 mm to 0.40 mm, and a proper value of pressure in a lower side of the bead, that is from -100 Pa to -700 Pa.
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