JPH07214976A - Refill of ball point pen - Google Patents

Abstract

PURPOSE:To effectively prevent a counterflow of ink caused at the time of writing in an upward posture of the ball point pen by loosely fitting a shaft- shaped piece having a taper to seat on a piece receiver at its rear end, and having an ink introduction groove and small diameter portion at the appropriate front outer periphery in a space permitting communication between a valve chamber and a tip inner bore. CONSTITUTION:In a condition of the chip 5 directed downward prior to writing, a piece 15 is in contact with a tip end ball 5a in its small diameter portion 18, and ink 22 that comes into a chamber 13 from an ink containing pipe 4 via an introduction hole 21 is conducted to the rear end of a tip end ball 5a through the introduction groove 16 of the piece 15. At this time, the tip end ball 5a is pressed and put into close contact with a caulked portion at its small diameter portion 18, so that direct flow is prevented. On the other hand, when the chip 5 is directed upward, the taper portion 17 of the piece 15 comes into close contact with a piece receiving seat 19 so as to seal the introduction hole 21, thus the counterflow of ink can be prevented through a head even in the case where ink beneath the tip end ball 5a is absent during upward posture writing.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention uses an ink having a so-called shear thinning property, which statically has a high viscosity, and the viscosity is lowered by the rotation of a ball during writing to cause the ink to flow out. Regarding improvement of ballpoint pen.

[0002]

2. Description of the Related Art The same applicant discloses in JP-B-4-52067 a mechanism for preventing backflow of ink in a ballpoint pen provided with a valve chamber in which a ball is loosely fitted. This is a synthetic resin mouth plastic with a required number of ridges that prevent balls from being pulled out in the valve chamber where the balls are loosely fitted, and when writing, the gap formed between the ridges. The ink is made to flow through the chip to communicate with the chip. There is also known a ball-point pen using an ink having a shear thinning property in which the viscosity is lowered by the rotation of the tip ball at the time of writing and the ink flows out. Generally, a ball-point pen using an ink having shear thinning viscosity has a large ink outflow amount (in order to increase the writing density) and has a large diameter of an ink containing tube to increase an ink loading amount. or,
Since the viscosity of the ink is smaller than that of the ink of the oil-based ballpoint pen, the flow resistance to the ink containing tube is small. Therefore,
Ink leakage (ink flows back to the rear end of the ink containing tube) easily occurs due to its own weight or impact. Therefore, a grease-like follower is provided at the trailing end of the ink, which normally moves following the consumption of the ink during writing, but which suppresses the backflow of the ink against its own weight and impact. However, even if the follower is provided, if ink immediately below the ball of the chip runs out when writing upward, there is a risk of conspicuous backflow due to direct addition of the ink head and soiling the hands and clothes. In addition, since the viscosity of the ink is low and the amount of outflow is large, if the tip side is faced down, the ink will bleed if there is a gap between the tip ball and the tip crimped portion (DC).
There is a problem.

[0003]

SUMMARY OF THE INVENTION An object of the present invention is to improve a ballpoint pen which uses ink having a shear thinning property in which the viscosity is lowered by the rotation of the ball during writing and the ink flows out. It is possible to prevent ink backflow caused by upward writing and impact and direct current when the tip side is placed downward, and to prevent stains on the barrel, the hand, and the clothes where the ballpoint pen refill is mounted.

[0004]

The refill of a ballpoint pen of the present invention devised to achieve the above object is a ballpoint pen having a tip of a joint and a ink container tube fixed to the rear end of the joint. In the refill, the valve chamber is connected to the rear end of the tip in the axial center of the joint, and a tapered piece receiving seat is provided at the rear of the valve chamber to allow close contact with the piece receiving seat in the rear. A shaft-shaped top with a taper part and an ink guide groove at the front outer peripheral required point and a small diameter part at the tip is loosely fitted in the space that communicates the valve chamber and the chip inner hole part, and when the chip side is facing upward The tapered portion is in close contact with the top receiving seat, the guide hole is sealed, and the sealed state is released when the chip side is facing downward, and the tip of the small diameter portion contacts the rear end of the tip ball, and the tip ball is the tip end. It is formed so that it is close to the Backflow and DC ink to be prevented.

[0005]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS In the embodiment of the present invention shown in FIGS. 1 and 2, a locking cylinder portion 7 and a fitting cylinder portion 12 are provided in the first half of the joint 3 and the front locking cylinder portion 7 has a circular shape. A rib 8 inclined forward in the axial direction is provided at a required position on the circumference. A tip fitting hole 10 is formed in the locking cylinder portion 7 from the front end, and the tip 5 is press-fitted into the tip fitting hole 10 from the rear end side.

The joint 3 is integrally formed of an elastically deformable synthetic resin and has a valve chamber 13 provided at the rear side thereof so as to communicate with the tip fitting hole 10. Also, the valve chamber 13
Ribs 14 are provided at required locations on the peripheral wall of
The inner circumference surrounded by is substantially the same in diameter as the inner hole portion of the chip 5. Further, a tapered piece receiving seat 19 is provided at the rear of the valve chamber 13. Further, the top 15 is loosely fitted in the space where the valve chamber 13 and the inner hole of the chip 5 communicate.

The frame 15 has a taper portion 17 at the rear end thereof which can be brought into close contact with the frame receiving seat 19, an ink guide groove 16 at a front outer peripheral required portion, and a shaft having a small diameter portion 18 at the tip. It is formed in a shape. The tip 5 is crimped so that the tip ball 5a is rotatably held in a state where the tip ball 5a is substantially in contact with a seat having a channel 5b into which ink can flow.

In the rear of the valve chamber 13, a guide hole 21 which communicates with the frame receiving seat 19 is formed, and ink is passed through the gap between the ribs 14 of the valve chamber 13 and the ink guiding groove 16 of the frame 15 to the tip 5. It is possible to flow into the rear end of the tip ball 5a.

A flange portion 20 is provided at the rear end of the locking cylinder portion 7 of the joint 3, and a fitting cylinder portion 12 is provided behind the flange portion 20.
Has been extended. A cylindrical ink containing tube 4 is press-fitted and fixed to the outer periphery of the fitting cylindrical portion 12 by abutting the tip of the ink containing tube 4 to the rear end of the collar portion 20, and the inner diameter portion of the ink containing tube 4 is guided to the guide hole 2 of the joint 3.
It communicates with 1. The ink containing tube 4 is filled with the ink 22 having a statically high viscosity and a shear thinning property that reduces the viscosity by the rotation of the ball during writing and allows the ink to flow out. The rear end of 20 is filled with a grease-like follower that can move in contact with the ink surface as ink is consumed. (Not shown)

As described above, the refill of a ballpoint pen constituted by fixing the tip 5 and the ink containing tube 4 filled with ink to the joint 3 is inserted into the barrel 1 and the joint 6 is attached to the front face of the shaft portion 6. The barrel 2 with the rear end edge of the collar portion 20 abutting against each other and the step portion 9 provided on the inner surface portion thereof, and the step portion 9 abutting against the peripheral surface of the rib 8 of the joint 3 It is screwed to the shaft portion 6.

[0011]

First, FIG. 1 shows a state before writing with the tip 5 facing downward, at which time the top 15 of the tip 15 has a small-diameter portion 18
Is in contact with the rear end of the tip ball 5a, and the ink 2 entering the valve chamber 13 from the ink containing tube 4 through the guide hole 21.
2 passes through the ink guide groove 16 of the top 15 and is guided to the rear end of the front ball 5a. In this state, the tip ball 5a is pressed against the caulked portion in the small diameter portion 18 in a pressed state, so that direct current is prevented. Also, the tip ball 5a can be
The ink retreats slightly so that a gap is created and ink flows out.
By writing, the viscosity decreases due to the rotation of the tip ball 5a, a large amount of ink flows out, there is no fluff, and writing with high density becomes possible.

Further, FIG. 2 shows a state in which the tip 5 is directed upward, and at that time, the taper portion 17 of the top 15 has the valve chamber 1
Since the guide hole 121 is tightly closed in close contact with the frame receiving seat 19 of No. 3, even if there is no ink directly below the tip ball 5a and the ink is written up, the head does not hit the ink and flow back.

When the ballpoint pen refill of the embodiment is mounted on the shaft cylinder 1, the mouthpiece 2 is screwed with the collar portion 20 of the joint 3 abutting against the front end of the shaft portion 6. At that time, The rib 8 of the stop cylinder portion 7 bites against the step portion 9 of the mouthpiece 2 in a biting manner, so that the tip 5 and the mouthpiece 2 are prevented from rattling.

[0014]

The structure and operation of the refill of the ball-point pen of the present invention are as described above, and it is possible to prevent ink from backflowing due to upward writing or impact by the piece loosely fitted in the valve chamber, and it is placed downward. Sometimes direct current is prevented, and accidents that stain the inside of the barrel, hands, clothes, etc. are prevented. Further, when the refill of the ball-point pen of the embodiment is mounted on the barrel, the tip and the mouthpiece are rattled, so that the writing feeling is good.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional view of a main part of a refill of a ball-point pen that is an embodiment of the present invention, showing a state in which a tip faces downward.

FIG. 2 is a vertical cross-sectional view of a main part of a ball-point pen that is an embodiment of the present invention, showing a state in which the tip is facing upward.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Shaft cylinder 2 Base 3 Joint 4 Ink storage tube 5 Chip 5a Tip ball 5b Channel 6 Shaft part 7 Locking cylinder part 8 Rib 9 Step part 10 Tip fitting hole 11 Shaft part 12 Fitting cylinder part 13 Valve chamber 14 Rib 15 Frame 16 Ink guide groove 17 Tapered part 18 Small diameter part 19 Frame receiving seat 20 Collar part 21 Guide hole 22 Ink

Claims (2)

[Claims] 1. A ballpoint pen tip is attached to the tip of the joint.
In the refill of a ball-point pen that has an ink storage tube fixed to the rear end, a valve chamber is connected to the rear end of the tip at the shaft center of the joint, and a valve seat is provided at the rear of the valve chamber. The shaft-shaped coma having a taper portion at the rear end so as to be in close contact with the coma receiving seat, the ink guiding groove at the front outer peripheral required portion, and the small diameter portion at the tip is the valve chamber and the tip inner hole. When the tip side is upward, the tapered portion is in close contact with the top receiving seat to seal the guide hole, and when the tip side is downward, the sealed state is released, and
A refill for a ball-point pen, wherein the tip of the small-diameter portion is in contact with the rear end of the tip ball so that the tip ball comes into close contact with the caulking portion of the tip of the tip. 2. The ink storage tube is filled with ink having a so-called shear thinning viscosity, which statically has a high viscosity and is reduced by the rotation of the tip ball during writing to cause the ink to flow out. The refill for a ballpoint pen according to claim 1, wherein the refill is a ballpoint pen.