JPH09315080A - Ballpoint pen - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a ballpoint pen having no adverse influence to ink discharge or valve function and no fear of a valve ball intruding into a control wall in the case of centrifugally inking due to deposit generated by the corrosion of the ball. SOLUTION: The ballpoint pen comprises a valve ball 3 longitudinally movable by own weight and a seat 4 in close contact with the ball 3 at the time of directing a nib upward in an ink flow channel 5 at the rear of an end all 2. The ball 3 is made of a ceramic. Further, the specific of the ball 3 is than that of ink 71 contained therein, and the specific gravity difference of the ball 3 and the ink 71 is set to 1 to 10.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a ballpoint pen. More specifically, the present invention relates to a ballpoint pen that accommodates a backflow prevention valve ball that can be moved back and forth by its own weight in an ink flow passage between a tip ball and an ink storage portion.

[0002]

2. Description of the Related Art A conventional ballpoint pen of this type (see FIG. 3).
A metal ball (for example, made of cemented carbide) is used as the backflow preventing valve ball 3a. The metal valve ball 3a is apt to corrode and cause the deposit C to be generated on the valve ball surface or in the ink, particularly when the ink contained in the metal is aqueous.
Then, the deposit C hinders smooth ink discharge from the tip ball, and in the worst case, writing becomes impossible, or valve closing between the valve ball 3a and the seat portion 4a becomes incomplete. Tend to be.

Further, since the conventional metal valve ball has a considerably large specific gravity as compared with the ink, even if the ink can be quickly dropped and moved by its own weight, the ink is moved to the pen tip side by the centrifugal separator. In a ball-point pen of a type having a step of pushing out, there is a risk that the valve ball will be strongly abutted against the restriction wall 62a and bite it.

Further, as shown in FIG. 3, when the seat portion 4a is made of metal together with the valve ball 3a made of metal, the valve ball 3a
And the seat portion 4a tend to be magnetic to each other, and even when the pen tip is facing upward, the valve ball 3a is adsorbed around the seat portion 4a, the valve ball 3a does not sit in the center hole 41a of the seat portion 4a, There is a risk that the valve will not be closed securely. The valve ball 3a
It is possible to demagnetize the magnetic valve ball 3a and the seat portion 4a in order to prevent the attraction between the seat portion 4a and the seat portion 4a, but this makes the assembly process complicated.

[0005]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems of the prior art. Corrosion of a valve ball causes deposits to adversely affect ink output and valve function, and centrifugal separation ink output. An object of the present invention is to provide a ballpoint pen in which the valve ball does not bite against the restriction wall during the process.
Further, it is an object of the present invention to provide a ballpoint pen in which the valve ball is not attracted to the seat portion by the magnetic force and the valve closing may not be incomplete. In the present invention, "front" means the pen tip direction,
"Back" refers to the tail plug direction.

[0006]

According to the present invention, there is provided a tip ball 2 comprising:
A ball-point pen 1 provided with a valve ball 3 which can be moved back and forth by its own weight and a seat 4 which comes into close contact with the valve ball 3 when the valve ball 3 is upwardly directed, in an ink flow path 5 behind the valve. It is required that the sphere 3 is made of a non-metallic inorganic material.

Since the valve ball 3 is made of a non-metal inorganic material, the valve ball 3 is not corroded and a deposit is not generated on the surface of the valve ball 3 or in the ink 71. Therefore, there is no risk of defective ink discharge or defective valve operation.

Further, the valve ball 3 made of the non-metallic inorganic material
In the above, the specific gravity of the valve ball 3 is changed to the ink 7
It is effective to make the specific gravity larger than 1 and set the difference in specific gravity between the valve ball 3 and the ink 71 [(specific gravity of valve ball)-(specific gravity of ink)] to 1 to 10. The specific gravity difference is 1
If it is smaller than the above value, the valve ball 3 cannot quickly drop and move in the ink 71 due to its own weight, and the valve function cannot be satisfied. On the other hand, when the specific gravity difference is larger than 10, the valve ball may vigorously come into contact with the regulation wall 62 and bite into the regulation wall 62 when the ink is discharged by the centrifuge. Therefore, when the difference between the specific gravities is in the range of 1 to 10 (preferably in the range of 3 to 8), the valve ball 3 has a sufficient weight to smoothly drop and move in the ink 71 as a valve body, and the centrifugal force is increased. In the case of the ballpoint pen including the separated ink discharging step, there is no risk that the valve ball 3 will bite the restriction wall 62.

In the ballpoint pen 1 in which the valve ball 3 is made of a non-metal inorganic material, it is effective that the seat portion 4 is made of metal. The metal seat part has a smoother flow in the parts feeder than the synthetic resin part, which facilitates the manufacture and assembly of the seat part. At the same time, even though the seat portion 4 is made of metal, the valve ball 3 is made of a non-metal inorganic material, so that it does not stick to the seat portion 4 due to magnetism, and the valve ball 3 is placed at the center of the seat portion 4. The hole 41 can be reliably seated. Further, the trouble of demagnetizing the valve ball 3 is unnecessary.

The non-metal inorganic material forming the valve ball 3 is
Non-magnetic material (non-conductor), specifically, ceramics (for example, inorganic materials such as zirconia, silicon carbide, silicon nitride, boron nitride, alumina, silica, calcia, magnesia, and their composite ceramics) and glass Etc. In particular, the material of the valve ball 3 is ceramic (especially zirconia (ZrO ₂ )) in that it is excellent in corrosion resistance against the water-based ink 71 and has a good specific gravity for dropping and moving in the ink. ) Is preferred.

[0011]

Embodiments of the present invention will be described with reference to the drawings.

FIG. 1 and FIG. 2 show an embodiment of the ballpoint pen 1 of the present invention (the pen tip is in an upward facing state). This embodiment is a ballpoint pen refill that is exchangeably housed in a barrel.
The refill is mainly composed of a metal (stainless steel) tip 8 that rotatably holds the ball 2 at the tip, and a synthetic resin holder 6 having the tip 8 fixed to the tip.
And an ink storage tube 7 having the holder 6 fixed to the tip.
Consists of

Inside the holder 6, a tip mounting hole 61 opening forward and an ink circulation hole 5 opening rearward.
And the two holes 5 and 61 are the through holes 63 of the restriction wall 62.
Are communicated via. In the chip mounting hole 61,
The ball-point pen tip 8 is press-fitted and fixed, while the valve ball 3 is loosely inserted into the ink circulation hole 5, and the seat portion 4 made of an annular body is press-fitted and fixed to the inner wall thereof. Further, on the outer surface of the front portion of the holder 6, a support cylinder 83 for holding the outer peripheral surface of the chip 8 is provided in order to prevent the chip 8 from being bent.
Is fixed.

The front surface of the regulation wall 62 is in contact with the rear end of the tip 8, and the rear surface thereof is in contact with the valve ball 3. The rear surface of the regulating wall 62 may be any as long as it regulates the forward movement of the valve ball 3 and at the same time secures the flow of the ink. The peripheral wall of the through hole 63 has a different shape (specifically, a step shape).

The valve ball 3 is a zirconia ball (outer diameter 0.7 mm, specific gravity 6.1), and is provided in a space (that is, a valve chamber) between the seat portion 4 of the ink flow passage 5 and the restriction wall 62. It is housed so that it can move back and forth. The seat 4 is obtained by cutting a stainless steel pipe (outer diameter 1.1 mm, inner diameter 0.6 mm) into an appropriate length (longitudinal dimension 2 mm).

The ink containing tube 7 is made of a semi-transparent synthetic resin, and the aqueous ink 71 having a shear thinning property (specific gravity 1.05 to 1.15) is directly contained therein, and further, The back end of the ink is filled with a grease-like backflow preventive agent 72 that moves toward the pen tip as the ink is consumed. A tail plug 9 having a vent hole 91 at the center is press-fitted and fixed to the rear end opening of the ink storage tube 7. After the ink 71 and the backflow preventive agent 72 are filled in the ink storage tube 7, the ink 71 and the backflow preventive agent 72 are moved to the pen tip side by a centrifugal separator, and the air (bubbles) in the ink 71 and the backflow prevention agent 72 is removed from the rear end of the ink storage tube. Is released to the outside. Also,
The zirconia balls are abutted and held by a weak force without hitting the regulation wall 62 during the centrifugal ink removal process.

The ball-point pen tip 8 comprises a cylindrical pipe made of stainless steel in which a tip ball 2 having an outer diameter of 0.3 mm is rotatably held at the tip. In the vicinity of the distal end of the pipe, three places on the outer peripheral surface are pressed and deformed at equal intervals from the outside to the inside to form a plurality of inward projections, whereby the ball receiving seat 81 is formed. Also, at the tip of the pipe,
It is pressed inward and deformed to form an inwardly tapered tip edge portion 82. A tip ball 2 is disposed between the front surface of the ball receiving seat 81 and the rear surface of the tip edge 82, and the tip ball 2 is connected to the ball receiving seat 81 and the tip edge 82.
Is held rotatably.

As shown in FIGS. 1 and 2, when the refill is in the upward state, the valve ball 3 drops in the ink 71 due to an appropriate specific gravity difference with the ink 71. Further, since the valve ball 3 is made of ceramic, it is hard to be magnetized, and is firmly seated in the center of the seat portion 4 without being attracted to the seat portion 4,
The central hole 41 is closed. On the other hand, although not shown, when the pen tip is directed downward, the valve ball 3 comes into contact with the restriction wall 62,
Ink circulation suitable for writing is secured without blocking the through hole 63 of the regulation wall 62.

The seat portion 4 may be formed integrally with the holder 6 or the tip 8. However, when the tip 8 is in the shape of a pipe having a relatively small diameter as in the present embodiment, the seat portion 4 is provided from the rear of the holder. It is effective to use a separate member that is press-fitted.

(Corrosion test) Two kinds of valve balls 3 (invention: zirconia ball, comparative example: cemented carbide ball) were applied to the refill, and three types of storage conditions (room temperature for 1 month,
The corrosion test was conducted at 50 ° C. for 1 month and 50 ° C. for 2 months. Table 1 shows the results.

[0021]

[Table 1]

As shown by the above results, the cemented carbide valve bulb was corroded at room temperature for one month, and the precipitate made it impossible to write. On the other hand, with a zirconia valve ball, 50 ° C2
Even after months, it did not corrode at all and was writable.

[0023]

In the ballpoint pen of the present invention, since the valve ball is made of a non-metal inorganic material, the valve ball does not corrode and deposits are not generated in the ink or on the valve ball surface. Therefore, there is no possibility of adversely affecting the ink discharge and the valve function, and a sufficient check valve function is satisfied for a long period of time.

Further, by specifying the specific gravity difference between the valve ball and the ink, the ink can be sufficiently dropped and moved, and in addition,
During the centrifugation process, the valve ball does not bite into the restriction wall.

When the seat portion is made of metal, the valve ball is made of a non-metallic inorganic material so that the valve ball is not attracted to the seat portion due to magnetism, and the valve ball is securely placed at the center of the seat portion. Can be seated on. In addition, the trouble of demagnetizing the valve ball is also unnecessary.

[Brief description of drawings]

FIG. 1 is a vertical sectional view of the ballpoint pen of the present invention.

FIG. 2 is an enlarged cross-sectional view of part A in FIG.

FIG. 3 is an enlarged sectional view corresponding to a portion A of FIG. 1 showing a conventional problem.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Ball-point pen 2 Tip ball 3 Valve ball 4 Seat part 41 Center hole 5 Ink passage (ink passage hole) 6 Holder 61 Chip mounting hole 62 Restriction wall 63 Through-hole 7 Ink storage tube 71 Water-based ink 72 Backflow inhibitor 8 Tip 81 Ball Receiving seat 82 Tip edge 83 Support tube 9 Tail plug 91 Vent

Claims (3)

[Claims] 1. A valve ball (3), which can be moved back and forth by its own weight, and an ink flow passage (5) behind the tip ball (2), and the valve ball (3) moves rearward when the pen tip is upward and closely contacts. A ball-point pen provided with a seat (4), which is characterized in that the valve ball (3) is made of a non-metallic inorganic material. 2. The specific gravity of the valve ball (3) is made larger than the specific gravity of the ink (71) housed inside, and the specific gravity difference between the valve ball (3) and the ink (71) is set to 1-10. The ball-point pen according to claim 1. 3. The ballpoint pen according to claim 1, wherein the seat portion (4) is made of metal.