Collector type writing instrument

Details Collector type writing instrument Collector type writing instrument

2002-06-14

2003-08-05

Walczak, David J. (Department: 3751)

Coating implements with material supply

Bifurcate pointed nib tool

Including reservoir and feeder

C401S223000, C401S227000

Reexamination Certificate

active

06602012

ABSTRACT:

TECHNICAL FIELD
The present invention relates to improvement of a free-ink collector type writing instrument having a point assembly as a writing portion at the tip, such as a ball-point pen, felt pen, fountain pen, etc., comprised of an ink tank for storing ink directly, a collector as an adjuster made up of multiple vanes for adjusting the internal pressure using capillary action, a means for feeding ink from the ink tank to the point assembly. The present invention particularly relates to improvement against deficiencies immediately after production and improvement of the collector in the internal pressure adjusting function to deal with change in temperature and change in pressure during use.
BACKGROUND ART
Writing instruments which have a collector disposed between a point assembly and ink tank for retaining free-state ink and regulating the pressure inside the ink tank so as to prevent ink leakage from the pen tip and ink from flooding from an air hole have been conventionally known.
There have also been known so-called sliver type pens which have a sliver of fabric bundles impregnated with a low viscosity ink of some mPa·s and an ink feed for feeding ink to their pen point. This sliver type pen, however, has the problem of ink consumption being indiscernible and the problem that an ample amount of ink flows out, and hence thick drawn lines can be obtained, in the starting stage but the flow amount gradually becomes lower, and hence the drawn lines become thinner, as the ink is used for writing. In order to smoothly deliver the ink from the sliver, the capillary capacity of the sliver may be set to be low. However, this setting will increase the occurrence of ink leakage and eruption from the sliver and smudging clothes due to impacts such as from being dropped. In contrast, if the capillary capacity of the fabric sliver is increased, there occurs an ink ejection problem in that the ink flow rate sharply lowers as the ink is used for writing and the drawn lines become considerably thin in the latter half of its life even though there is still an abundant amount of ink left.
A collector writing instrument has some advantages that it delivers ink at a flow rate equal to or above that of a sliver type writing instrument at the starting stage and will not gradually reduce its ink flow rate and is able to provide thick lines even without applying any extra writing force until its life's end, that it can be charged with a large amount of ink and that the amount of free-state ink left can be checked.
As shown in
FIGS. 7 and 8
, in a collector writing instrument, once air inside ink tank
3
expands or contracts due to variation of the external air in pressure or due to change in temperature, ink
2
moves between collector
6
and ink tank
3
(or air enters the tank through a narrow ink channel
14
and air/liquid exchanger
18
) so as to adjust the internal pressure, whereby it is possible to prevent ink
2
from leaking out from the tip
9
of a point assembly
1
. Since, if the capacity of ink tank
3
is large the expansion/contraction of the air space in tank
3
becomes large, a certain relationship has been found between the capacity of ink tank
3
and the maximum ink retention capacity of collector
6
. Conventionally, there has been completed inventions and commercial products which use a collector having a capacity of about 10% or more of the ink tank capacity.
There exist some collector writing instruments which bring about a flooding problem if reduction and increase in pressure due to change in temperature, variation in pressure, change in altitude or any other change is repeated. However, conventionally, if the performance of a collector writing instrument under a temperature rise from room temperature at about 20° C. to about 50° C., which is conceivably the maximum atmospheric temperature, is validated, the writing instrument is considered as having a good performance free from problems. However, in the cases where a writing instrument which has been put under winter ambient air is carried to the front of a heater, the writing instrument will undergo a sharp temperature rise from 0° C. to 50° C. In such a case, the conventional writing instruments would cause ink flooding and other problems.
In order to solve the flooding problem, some countermeasures can be considered such as enlarging the maximum ink retention of collector
6
(making the diameter or length greater), reducing the size of ink tank
3
and other methods. However, all these methods have some drawbacks: that is, a style problem due to enlargement of the barrel size; lowering of cost performance due to reduction in ink amount and hence short life; and the problem of forward leakage being likely to occur due to a too long collector
6
or a too long distance from air/liquid exchanger
18
to tip
9
of point assembly
1
(to be called ‘ink head H’ hereinbelow). Alternatively, to reach a solution with ink
2
, an ink
2
has to have an extremely low wetting ability, which means compromising the writing performance.
On the other hand, when a collector 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 through an air groove
15
inside collector
6
, whereby ink
2
floods out from an 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 Laid-open Hei 3 No. 31581 and Japanese Patent Application Laid-open Hei 9 No. 104194, and others. However, these disclosures only provide the function of slightly weakening the flush inside the collector.
A collector writing instrument is configured so that air/liquid exchanger
18
is wetted with ink
2
and ink
2
or air is replaced only through air/liquid exchanger
18
having a high enough capillarity. A collector writing instrument is one which makes use of the mechanism that the internal pressure on the ink tank
3
side is substantially reduced by the function of a meniscus formed by the capillarity of air/liquid exchanger
18
to prevent ink
2
from flowing out even when it is oriented downwards.
For this reason, it is necessary to wet air/liquid exchanger
18
near the rear end of collector
6
and partitioning portion
19
around the exchanger at almost the same time when assembled. If this wetting with ink
2
is not enough to fully create shutoff, air will flow into the ink tank
3
side other than through air/liquid exchanger
18
so that the reduction of ink tank
3
in pressure by the function of the meniscus cannot be achieved. This results in a deficiency in that the ink
2
leaks to point assembly
1
or the retaining portion of collector
6
without a break. Conventionally, impacts used to be applied immediately after assembly to wet the rear end portion, or the instrument used to be left to stand with its pen tip set downward for a certain period of time to fully wet the rear end portion. However, these production processes have so far entailed insufficiency of wetting, a necessity of long period of time in production and other drawbacks.
Enhancement of the resistance against flooding can be achieved by increasing the capacity of collector
6
. However, if collector
6
is made longer to avoid the thickness problem, the ink head H applying on the point assembly becomes higher, whereby a forward leakage problem, i.e., the problem of ink
2
leaking out from point assembly
1
occurs. Therefore, it has been impossible in conventional configurations to simply make collector
6
longer to increase the capacity of collector
6
.
In order to improve the resistance against flooding, the applicant he

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