Coating implements with material supply – Material flows through porous tool – Wick feed from within reservoir to tool
Reexamination Certificate
2000-12-15
2001-10-16
Douglas, Steven O. (Department: 3751)
Coating implements with material supply
Material flows through porous tool
Wick feed from within reservoir to tool
C401S223000, C401S225000, C401S227000, C401S229000, C401S230000
Reexamination Certificate
active
06302610
ABSTRACT:
BACKGROUND OF THE INVENTION
(1) Field of the Invention
The present invention relates to a direct-feed type writing implement.
(2) Description of the Prior Art
Conventional direct-feed type writing implements which use so-called raw ink, i.e., liquid ink, are known to employ an ink collector making use of capillary action, e.g., of a vane-like regulator or a fiber bundle for temporal retention of ink, in order to prevent ink leakage due to expansion of the air inside the ink tank accompanying change in ambient conditions such as reduction in pressure and/or increase in temperature.
In a writing implement using the ink collector, in order to positively prevent forward leakage of ink from the writing point side, the size of the ink collector is designed based on the maximum expansion, estimated from the ink tank volume. Therefore, the design of the size of the ink collector depends on the size of the ink tank. That is, the larger the ink tank, the greater the ink collector needs to be.
However, forming a larger ink collector means more cost. There is another drawback in that making the ink collector larger in diameter results in the loss of stylish appearance. Alternatively, if the ink collector is long, the feeder means such as a center core or the like which penetrates through the ink collector and leads ink to the writing portion becomes long, so that the long collector configuration produces disadvantages as to forward leakage since the head of ink acts on the writing portion.
In general, it is well known that the ink retention volume of the ink collector is set at 10 to 30% of the ink tank volume. However, there have been demands for the reduction of the size of the ink collector while keeping the ink tank size, or for enlarging the size of the ink tank while keeping the ink collector as is.
Conventionally, a configuration using an ink absorber provided in the ink tank is disclosed in Japanese Patent Application Laid-Open Hei 4 No. 227886. As shown in
FIGS.1
to
3
, this configuration includes a capillary liquid retainer
215
, i.e., the ink absorber as a center core for feeding ink to the writing tip
212
and an air supply pipe
213
. This conventional configuration is an applicator
210
wherein a liquid suctioning device
216
is isolated at a position when the writing point is set approximately downwards. Actually, when the writing point is oriented downwards as in normal writing, no ink is supplied to liquid suctioning device
216
, hence the ink reserved in liquid suctioning device
216
is the only ink supply for writing, resulting in a short writing distance.
A further description about the prior art disclosed in Japanese Patent Application Laid-Open Hei 4 No. 227886 will be made with reference to
FIGS. 1
to
3
. In applicator
210
, air supply pipe
213
allows a liquid container
211
to be filled with air equal in volume to that of outflow of liquid
217
and also is to prevent liquid
217
from flowing through the opening formed in air supply pipe
213
and directing the liquid into air
214
, in cooperation with a space
227
or a capillary medium
226
provided in the space
227
. This means that no ink will enter air supply pipe
213
and will be supplied to the writing portion and ink supply to the writing portion is provided only by liquid
217
stored in capillary liquid retainer
215
. Therefore, in this conventional case, the ink reserved in the capillary liquid retainer is the only ink supply, resulting in a short writing distance, as described above.
Japanese Patent Application Laid-Open Hei 4 No. 227886 also discloses a prior art configuration shown in
FIG. 2
in which liquid
217
is stored in a contractile tube
224
accommodated in an inner space
225
of liquid container
211
so as to fill almost the entire inner space
225
with liquid
217
. This means that if no contractile tube is used, the entire inner space
225
cannot be filled up with liquid
217
, i.e., ink. The fact that liquid
217
cannot fill the entire inner space but can only fill up to about half, is obvious in FIG.
1
and in another embodiment shown in FIG.
3
. Therefore, in order to fill the whole container of the ink tank with ink, the above-mentioned tube is a must. Therefore, configurations without such a tube have the drawback in that inner space
225
or the entire ink tank cannot be filled up with ink.
On the other hand, in the case where inner space
225
or the ink tank using such a tube is filled with ink, the following problem occurs. When the tube is formed of rubber or the like having elasticity, the pressure due to contraction of the rubber or the like is continuously applied to liquid
217
or the ink. This situation is the same when the writing point is set upwards. In the conventional configuration shown in
FIG. 2
, disclosed in Japanese Patent Application Laid-Open Hei 4 No. 227886, since liquid
217
is able to enter capillary liquid retainer
215
due to the function of a valve means
220
when the writing point is set upwards, the ink under pressure infiltrates capillary liquid retainer
215
, causing leakage from the tip, designated at
212
. When the tube is formed of a non-elastic material, no pressure from elasticity acts on the ink. Therefore, with consumption of liquid
217
, air will enter tube
224
forming a space in order to compensate for the volume of ink consumed. If such a space is formed and if the space expands due to increase in temperature, reduction in pressure or any other reason, liquid
217
is able to enter capillary liquid retainer
215
when tip
212
or the writing point is set upwards. Therefore, also in this case, ink will reach tip
212
via capillary liquid retainer
215
and finally the ink or liquid
217
will leak from the tip. It may be considered that this ink leakage problem occurring when the writing point or tip
212
is put upwards is solved by providing a vent near tip
212
. However, when tip
212
is put downwards, since from the structure of the design, neither ink nor air will enter capillary liquid retainer
215
through valve means
220
, if the air expands due to increase in temperature and/or reduction in pressure, ink will leak from the vent provided near tip
212
. Thus, from a practical view point, it is difficult for the structure using the tube disclosed in Japanese Patent Application Laid-Open Hei 4 No. 227886 to provide a writing implement in which the entire ink tank can be filled up with ink.
Thus, the invention disclosed in Japanese Patent Application Laid-Open Hei 4 No. 227886, by any means, faces difficulties in filling the ink tank with ink, and has the drawback in that the entire ink tank cannot be filled up with ink.
The drawings related to the examples shown in Japanese Patent Application Laid-Open Hei 4 No. 227886, illustrate configurations in that the opening formed in air supply pipe
213
is not dipped in ink and is continuously open to the atmosphere when the writing point is set downwards. In the case as above where inner space
225
is put in communication with the atmosphere, if the pen has a low ink retention as when capillary liquid retainer
215
has a high porosity, there occurs a drawback that ink will leak forwards from the writing point. To deal with this, if a capillary liquid retainer with a low porosity is used to prevent forward leakage, the ink retention becomes high, causing difficulties in ejecting ink from the writing point, hence degrading ink supply during writing as a writing implement whilst producing drawn lines of low-density.
SUMMARY OF THE INVENTION
The present invention is to solve the above problems. Particularly, the object of the present invention is to provide a direct-feed type writing implement having an ink tank equal in volume to that of the conventional configuration but using an ink collector smaller than that of the conventional configuration, or to provide a direct-feed type writing implement having a ink collector equal in size to that of the conventional configuration but being able to store a greater amount of ink than the conventional conf
Furukawa Kazuhiko
Mito Yosuke
Darby & Darby
Douglas Steven O.
Mitsubishi Pencil Kabushiki Kaisha
Prunner Kathleen J.
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