Radiation imagery chemistry: process – composition – or product th – Radiation sensitive product – Silver compound sensitizer containing
Reexamination Certificate
2001-12-11
2003-04-29
Chea, Thorl (Department: 1752)
Radiation imagery chemistry: process, composition, or product th
Radiation sensitive product
Silver compound sensitizer containing
C430S531000, C430S617000, C430S935000, C430S965000, C118S410000, C427S420000
Reexamination Certificate
active
06555309
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a method for manufacturing photosensitive materials and particularly a method of manufacturing photothermographic materials by bead coating.
BACKGROUND OF THE INVENTION
Simultaneous multiple bead coating is used for manufacturing a photosensitive materials to apply multiple layers of photosensitive materials to a web. A multiple slide hopper shown in U.S. Pat. No. 2,761,791 is one of well-known coating apparatus for making simultaneous multiple coating through a bead of multiple layers formed between a lip of the multiple slide hopper, where a layered coating liquid flows by gravity on a inclined slide surface of the hopper, and a running web.
This slide bead coating can easily control a coating thickness by adjusting a web running speed and a feeding rate of coating liquid, and is suitable way for having thin layer coating which gives good photosensitive resolution and for making simultaneous multiple coating which increases productivity and decreases possibility of coating defects.
Slide bead coating, however, occasionally causes streak-like coating defect, which results in streak-like unevenness of optical density when the coated photosensitive product is used. It seems to happen more in the coating of photothermographic materials, which lowers quality of the product.
SUMMARY OF THE INVENTION
An object of the invention is to provide a coating method for manufacturing photosensitive materials, especially manufacturing photothermographic materials, with free from streak-like coating defect.
To accomplish the object studies were made and it is found that when the outer side layer includes materials capable of increasing optical density such as toner, streaks become more visible, and the streaks defect is restrained when meniscus curvature of upper side bead becomes less than a specified value. More specifically, the followings are inventions as described in the claim.
Method for manufacturing photosensitive materials comprising steps of: forming a liquid multilayer composite of a plurality of distinct layers on a slide hopper and; forming a bead of the liquid multilayer composite between a lip of the slide hopper and a running web so that an upper meniscus curvature of the bead is less than 7.2 mm
−1
.
Method according to above, wherein the liquid multilayer composite includes a liquid photosensitive layer containing a silver salt of organic acid and a hydrophobic polymer latex and a liquid non-photosensitive layer containing a water-soluble polymer.
Method according to those two of above, wherein the upper meniscus curvature of the bead being less than 7.2 mm
−1
is accomplished by selecting a proper value of clearance between the web surface and the lip of the slide hopper and a proper value of pressure in a lower side of the bead.
The proper value of clearance ranges from 0.10 mm to 0.40 mm and the proper value of pressure ranges from −100 Pa to −700 Pa. The coating liquid of the photosensitive layer has thixotropy that a viscosity of the liquid shows from 300 mPa·s to 30,000 mPa·s at shear rate 0.1/s and from 1 mPa·s to 100 mPa·s at shear rate 1000/s.
REFERENCES:
patent: 2761791 (1956-09-01), Russell
patent: 4113903 (1978-09-01), Choinski
patent: 4525392 (1985-06-01), Ishizaki et al.
patent: 5290660 (1994-03-01), Eian et al.
patent: 6013327 (2000-01-01), Naruse et al.
patent: 0 883 022 (1998-12-01), None
patent: 2 029 733 (1980-03-01), None
patent: 2 070 459 (1981-09-01), None
patent: WO 99/46640 (1999-09-01), None
Patent Abstracts of Japan vol. 017, No. 606 (C-1128), Nov. 8, 1993 & JP 05 185007 A (Fuji Photo Film Co Ltd), Jul. 27, 1993.
Patent Abstracts of Japan vol. 2000, No. 11, Jan. 3, 2001 & JP 2000 225368 A (Konica Corp), Aug. 15, 2000.
Chea Thorl
Fuji Photo Film Co. , Ltd.
Sughrue & Mion, PLLC
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