Coating implements with material supply – Bifurcate pointed nib tool – Including reservoir and feeder
Reexamination Certificate
2002-06-17
2003-09-16
Walczak, David J. (Department: 3751)
Coating implements with material supply
Bifurcate pointed nib tool
Including reservoir and feeder
C401S227000
Reexamination Certificate
active
06619871
ABSTRACT:
TECHNICAL FIELD
The present invention is directed to improvement of so-called collector type writing instruments, such as ball-point pens, felt tip pens, markers, fountain pens, small-tube writing instruments and the like, having a writing point at the front end thereof, an ink tank for directly storing ink and a collector or grooved adjuster for absorbing variation in internal pressure. In particular, the present invention relates to improvement of the mechanism to solve the flooding problem occurring when a collector type writing instrument is used under conditions in which a sharp pressure variation occurs such as on an airplane.
BACKGROUND ART
Writing instruments which have a collector
6
as an internal pressure adjuster, disposed between a conventionally existing point assembly
1
and ink tank
3
, for retaining free-state ink
2
and adjusting the pressure inside ink tank
3
so as to prevent ink leakage from a tip
9
of point assembly
1
and ink flooding from an air hole
10
have been known (see FIG.
27
). A collector type writing instrument can adjust the internal pressure balance by holding ink
2
of a relatively low viscosity from ink tank
3
within retaining grooves
13
formed in collector
6
and returning ink to ink tank
3
, meaning that it provides the function of protecting the writing point from the influence of changes in pressure. A collector type writing instrument has excellent performance such as capabilities of providing an ample amount of ink, securing the stable amount of ink flow down to the last drop and allowing for the amount of ink
2
left to be checked from the outside.
However, since the collector type writing instruments store ink
2
directly and allow movement of ink
2
to and from collector
6
, there is a serious drawback that ink
2
will flood outside through air hole
10
of the writing instrument there being no space for withholding ink
2
, thereby polluting fingers or clothes if the writing instrument is exposed to an environment in which the ink inside collector
6
exceeds the maximum capacity of retention, which is the limitation of the internal pressure adjustment capacity. As the countermeasures for solving this problem or increasing the safety to some degree, it is possible to make collector
6
greater in capacity or make ink tank
3
smaller. There have already been writing instruments sold on the market which use a collector capable of preventing ink flood under usual environments, meaning gentle temperature changes and the like.
As the current situation is that collector type writing instruments use rather thick barrels, taking a safety margin into account, use of a thicker barrel than the present situation makes the instrument difficult to grip and loses the stylishness. When ink tank
3
is made smaller, reduction of ink stored makes the life short. When the normal collector
6
is made longer, the ink head H becomes higher because the ink head H acting on point assembly
1
is proportional to the height from the air/liquid exchanger
18
to the tip
9
of the writing assembly, hence forward leakage of ink
2
from tip
9
occurs due to gravity.
On the other hand, when a writing instrument which has been capped under about 1 atm. on the ground and is uncapped inside an airplane in which the air pressure is generally reduced to about 0.8 atm., the interior of the pen which has been balanced under 1 atm., is instantaneously exposed to an environment of about 0.8 atm., so ink
2
inside moves in a rush and floods the space around the air channel of collector
6
, whereby ink
2
floods out from air hole
10
, being unable to be properly retained by the whole part of retaining grooves
13
. In order to solve the flood problem occurring under conditions in which the air pressure varies, devices and inventions have been disclosed in Japanese Utility Model Publication Hei 3 No.31580, Japanese Utility Model Publication Hei 3 No.31581 and Japanese Patent Application Laid-open Hei 9 No.104194, and others. However, these disclosures only provide the function of blocking the flush to directly reach the air hole, which is not efficient enough, hence a further effective improvement or other ways to reach a solution have been demanded.
There has been an invention which uses an air supply pipe and the like as disclosed in Japanese Patent Application Laid-open Hei 4 No.227886. However, the conventional invention has the problem that the instrument cannot write continuously unless the writing element is turned down-side up for ink supply and also has the problem of ink capacity being only half filled up from the beginning. Therefore, it is necessary to add such usage instructions or explanation as to the initially reduced amount of ink, for the consumers. Since it is considered that the instrument may be used in an environment in which sharp increase and reduction in air pressure repeatedly occur as in the situations where the instrument is carried over from one airplane to another or from low temperature outdoor air to the front of a heater, there have been demands for excellent free-ink collector type writing instruments which do not need any usage explanation to consumers as above, adopt effective countermeasures against such repeated changes and still can provide beneficial writing comfort (writing performance) making use of low-viscosity ink.
Further, since collector type writing instruments have the problem that the life of writing abruptly ends when ink runs out, it is necessary to carry a spare if the writing instrument has a low amount of ink. There is a demand for collector type writing instruments which can provide an ample amount of ink, which is the main feature of collector type writing instruments, until nearly the end of writing and can provide the performance of a fabric sliver type instrument, which delivers gradually reducing amounts of ink, for a short time so that the pen can be used to take some notes after the last drop of ink is used up. There are also other problems, including the problem of ink dropping from the writing point making it difficult to write when the pen has been kept upside down for long time and the problem of ink leaking forwards due to deficiency of the inherent function of a collector type writing instrument because ink drops and the air/liquid exchanger dries when the pen is held with its tip up and the air/liquid exchanger cannot be wetted again with ink even when the pen is returned with its tip down if there is a part in the way that blocks ink. Even when an equal amount of ink is loaded, a collector type writing instrument delivers a greater amount of ink than a conventional fabric sliver type writing instrument and hence has a shorter life. Therefore, there is a demand that downsizing of the ink tank volume should be avoided as far as possible. There is a demand for solving these problems.
As ink
2
is consumed during writing, collector type writing instruments are adapted to take external air into the ink tank
3
side through air/liquid exchanger
18
so as to avoid reduction in internal pressure (FIG.
27
). Therefore, it is usually necessary to provide a space in the rear of collector
6
for allowing free movement of air bubbles. As conventionally disclosed in Japanese Utility Model Application Laid-open Sho 59 No.184682 and other publications, there are configurations in which a solid article such as an ink absorber etc., is arranged in the ink tank, in contact with the rear of the collector. In such a configuration, if air bubbles arising at the air/liquid exchanger do not pass through the ink absorber, which is wetted with ink, without resistance, the ink absorber itself will function as a second air/liquid exchanger, whereby the internal pressure inside the writing instrument lowers, causing ink starvation and other writing deficiencies.
To solve the above problem, it is necessary to provide an arrangement which will not confine the rear of the ink collector or any other countermeasure. However, the air/liquid exchanger in the collector is usually provided at a single s
Furukawa Kazuhiko
Sano Yojiro
Mitsubishi Pencil Kabushiki Kaisha
Walczak David J.
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