Photography – Camera detail – Detachable or removable film holder unit
Reexamination Certificate
2002-12-26
2003-11-25
Mahoney, Christopher (Department: 2851)
Photography
Camera detail
Detachable or removable film holder unit
C242S348400, C428S091000, C026S02900R
Reexamination Certificate
active
06652166
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a light-sensitive material light-shielding container comprising a light-shielding cloth (also called ‘teremp’) that is attached, for the purpose of light shielding, to upper and lower inner wall surfaces of a slit-shaped opening through which the light-sensitive material passes, the slit-shaped opening being formed in a cartridge body of a photographic film cartridge, a magazine for housing printing paper or light-sensitive material for printing, etc.
2. Description of the Related Art
A photographic film cartridge comprises as minimum constituent features a spool, a cartridge shell, a pair of caps attached to opposite sides of the shell, and a photographic film wound around the spool, and has a configuration in which the photographic film is unexposed prior to use, the entirety or the majority thereof is wound around the spool within the cartridge shell, the photographic film is pulled out of the cartridge shell within a camera and exposed to an image, and it is again wound into the cartridge shell.
JP-A-7-152114 (JP-A denotes a Japanese unexamined patent application publication) discloses a light-shielding cloth for a photographic film cartridge in which a napped cloth is used. This publication discloses that a two-stage napping is carried out twice and, preferably, three times. In this publication, the height of the nap is adjusted by shearing, and although it is possible to control the height of the nap by shearing, there is the problem that fiber waste is easily generated.
JP-A-2000-206649 discloses the removal of fiber waste by immersion in water after napping, thus lessening the fiber waste. However, it is difficult to completely remove the fiber waste even by immersion in water after shearing. There has been therefore a desire for the height of nap to be controlled precisely without shearing.
BRIEF SUMMARY OF THE INVENTION
It is an object of the present invention to provide a photographic film cartridge comprising a napped light-shielding cloth formed from inexpensive warp and weft in which generation of fiber waste during napping can be suppressed, the thickness can easily be controlled to give a target value, and the light-shielding performance and film drawing-out performance are both excellent.
The present inventors have carried out an intensive investigation into inexpensive napped cloth in terms of the optimum rotational speeds of coarse napping and fine napping and the optimum number of times napping is carried out in order to achieve the light-shielding performance of the cartridge and the film drawing-out torque, and as a result the present invention has been accomplished.
The above-mentioned object has been attained by the following means.
That is, it is achieved by a photographic film cartridge comprising a light-shielding cloth that is attached to a photographic film cartridge outlet slit through which a film is drawn out, the light-shielding cloth being a cloth that is subjected to napping, the napping comprising napping with a coarse napping machine and then napping with a fine napping machine, the napping machines having napper rollers comprising a pile roller that rotates in the direction in which the cloth advances and a counter roller that rotates in the direction opposite to the direction in which the cloth advances, the rotational speed of the pile roller of the fine napping machine being higher than the rotational speed of the pile roller of the coarse napping machine and the rotational speed of the counter roll of the coarse napping machine being higher than the rotational speed of the counter roller of the fine napping machine, the napping being carried out so that the cloth thickness obtained by napping using the fine napping machine is less than the cloth thickness obtained by napping using the coarse napping machine, and a further napping being carried out using the fine napping machine so that the cloth thickness is greater than the cloth thickness obtained by napping using the coarse napping machine.
REFERENCES:
patent: 4468844 (1984-09-01), Otto
patent: 5084948 (1992-02-01), Nielsen et al.
patent: 5815896 (1998-10-01), Dischler
patent: 5860613 (1999-01-01), Holland
patent: 7-152114 (1995-06-01), None
patent: 8-15825 (1996-01-01), None
patent: 2000-29175 (2000-01-01), None
Kawasaki Hidetoshi
Mizuno Kazunori
Fuji Photo Film Co. , Ltd.
Mahoney Christopher
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