Coating implements with material supply – Including ball – roller or endless-belt tool – Ball
Reexamination Certificate
2000-11-17
2001-11-27
Walczak, David J. (Department: 3751)
Coating implements with material supply
Including ball, roller or endless-belt tool
Ball
Reexamination Certificate
active
06322270
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a tip assembly of a ball point pen, and more particularly to a tip assembly of a ball point pen, wherein the tip assembly comprises a writing ball, a ball housing a front end portion of which rotatably holds the writing ball therein, and a holder on a front end portion of which the ball housing is fixedly mounted.
2. Description of the Related Art
In writing operations, a writing ball rotatably mounted in a front end portion of a ball point pen is brought into contact with a recording medium such as a sheet of paper and the like (herein after referred to simply as the paper) which gives a frictional resistance to the writing ball to cause the ball to rotate. Such rotating ball draws the ink out of an ink reservoir of the ball point pen to apply the thus drawn ink to the paper. In a conventional ball point pen, as shown in
FIGS. 3 and 4
, the writing ball
21
is formed from a thin wire member, and rotatably held in a bore drilled in a front end portion of the ball housing
22
by caulking a peripheral portion of the bore. Prior to performing such caulking operation of the bore in the front end portion of the ball housing
22
, an ink channel member
4
provided with a plurality of radial grooves
3
for forming ink flow passages is mounted in the bore. Consequently, after completion of the caulking operation, the writing ball
21
is seated on a seat surface of the ink channel member
4
.
Until recently, in most cases, the ink used in the ball point pen has been of oil-based solution type. However, in these day, ink of aqueous solution type tends to be increasingly used in the ball point pen. The aqueous solution type ink comprises: aqueous liquid type ink; and, aqueous gel type ink. The latter, i.e., aqueous gel type ink is larger in viscosity than the aqueous liquid type ink, and capable of keeping its viscosity at relatively high level when stored. However, in writing operations, the aqueous gel type ink has its viscosity decreased since the aqueous gel type ink has a so-called “thixotropy properties”. Due to the presence of such thixotropy properties, even when the aqueous gel type ink is used in the ball point pen, there is a fear that the ink leaks from the tip portion of the ball point pen to damage a user's clothes and documents, particularly pockets of the user's clothes. In order to solve the above problem, the conventional ball point pen is provided with a mechanism (shown in
FIG. 4
) for prevent the ink from leaking the tip portion of the ball point pen. In this conventional mechanism shown in
FIG. 4
, a compression coil spring
24
is inserted between the writing ball
21
and an inner axial front surface of the holder
23
so as to extend over substantially the entire length of the ball housing
22
, and thereby resiliently urging the writing ball
21
forward.
However, in this conventional mechanism, as shown in
FIG. 4
, the coil spring
24
is constructed of three portions, i.e.,: a rear seating portion
24
a
; an intermediate portion
24
b
which is smaller in outer diameter than the rear seating portion
24
a
; and, a front linear portion
24
c
which is further smaller in outer diameter than the intermediate portion
24
b
. Since the coil spring
24
is very small in size and should be precisely formed in production, it is hard to produce such tiny and complicated coil spring
24
. Consequently, the coil spring
24
causes the manufacturing cost of the ball point pen to increase. Furthermore, the front linear portion
24
c
of the coil spring
24
is very thin in diameter, and therefore often trapped in one of the radial grooves
3
of the ink channel member
4
; which makes it impossible for the coil spring to properly urge the writing ball
21
forward.
SUMMARY OF THE INVENTION
In view of the above problem inherent in the conventional ball point pen, the present invention was made. Consequently, it is an object of the present invention to provide a tip assembly of a ball point pen, wherein the tip assembly is simple in construction, capable of operating without fail, and produced at a relatively low cost.
In accordance with the present invention, the above object of the present invention is accomplished by providing:
A tip assembly of a ball point pen, comprising:
a ball housing (
1
) a front end portion of which is caulked to rotatably hold a writing ball (
2
) therein;
a holder (
5
) having its front portion and its rear end portion inserted into the ball housing (
1
) and an ink reservoir pipe (
15
), respectively, wherein the rear end portion of the holder (
5
) is reduced in diameter and extends rearward to form an ink inlet portion (
9
) provided with an ink inlet opening (
10
), wherein a rear end opening of the ink inlet portion (
9
) is closed with a spring support (
11
); and
an linear spring (
12
) movably received in the holder (
5
), wherein the linear spring (
12
) has a length slightly longer than a distance between the writing ball (
2
) and an inner axial end surface of the spring support (
11
).
In the tip assembly of the ball point pen having the above construction, preferably, the linear spring (
12
) is constructed of a resilient filament having a diameter of from approximately 0.1 to approximately 0.25 mm.
Further, preferably, the resilient filament of the linear spring (
12
) is made of a stainless steel.
Still further, preferably, the resilient filament of the linear spring (
12
) is made of a synthetic resin.
Further, preferably, the spring support (
11
) has the inner axial end surface thereof formed into a V-shaped concave form in longitudinal section of the spring support (
11
).
The ink jet recording head having the above construction has the following effect: namely, since the means for urging the writing ball
2
is constructed of the linear spring
12
, it is possible to produce such linear spring
12
at a low cost. In addition, since it is also possible to increase the linear spring
12
in its filament diameter, there is no fear that a front end portion of the linear spring
12
constantly urging the writing ball
2
forward is trapped in the radial grooves
3
of the ink channel member
4
, which ensures that the writing ball
2
of the ball point pen of the present invention is capable of performing proper writing operations without fail.
REFERENCES:
patent: 5056949 (1991-10-01), Petrillo
patent: 5277510 (1994-01-01), Okamoto et al.
patent: 5906447 (1999-05-01), Horikoshi
patent: 5988922 (1999-11-01), Bussiere
patent: 6042290 (2000-03-01), Ishikawa et al.
patent: 6193429 (2001-02-01), Kim
deVore Peter
Schmeiser Olsen & Watts
Tokyo Sign Pen Mfg. Co., Ltd.
Walczak David J.
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