JPH0683376U - Ballpoint pen - Google Patents

Abstract

(57) [Abstract] [Purpose] A ball-point pen having an ink backflow prevention mechanism in which a ball is loosely fitted in a valve chamber, and it is possible to solve the inconvenience that occurs when inserting a ball or centrifuging. [Structure] A ball receiving seat is provided at a rear portion, a valve chamber in which a ball is loosely fitted is provided at a substantially central portion in an axial direction, a tip fitting hole communicating with a front portion of the valve chamber, and a rear portion behind the valve chamber are provided. In a joint in which guide holes communicating with the valve chamber are coaxially provided, the back hole of the tip is appropriately eccentric with respect to the axial center of the tip fitting hole, and a groove or protrusion is formed on a side surface of the valve chamber hole at a required position. A ball is loosely fitted in the valve chamber, a chip is fitted in the tip fitting hole of the joint, and an ink containing tube is fitted in communication with the guide hole.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to an improvement of a ballpoint pen having an ink backflow prevention mechanism.

[0002]

[Prior art]

 The same applicant discloses, in Japanese Utility Model Publication No. 4-52067, an ink backflow prevention mechanism for a ball pen provided with a valve chamber in which a ball is loosely fitted. This product has a synthetic resin mouth plastic with a required number of protrusions that prevent the ball valve from being pulled out in the valve chamber where the ball valve is loosely fitted, and is formed between the protrusions when writing. The ink is made to flow to the chips by communicating with the gaps. The mouth plastic is obtained by injection molding, but it is difficult to obtain dimensional accuracy because the ridges are undercut at the time of mold release, and it is troublesome to prevent damage to the ridges by inserting the ball valve. Also, during manufacturing, centrifugal treatment is performed to remove air bubbles that have become trapped after ink filling, but at that time there is the inconvenience that the ball valve bites into the ridge due to centrifugal force and the ball valve is fixed. . In addition, a so-called oil-based ballpoint pen using a high-viscosity ink and a so-called water-based ballpoint pen in which the ink is contained in a fibrous batting and the ink is guided to a ballpoint pen tip through an ink guiding core are known. Each of them has some drawbacks, but one of the shortcomings is that the oil-based ballpoint pens have the drawback that the ink is highly viscous and the ink is less voluminous and writing. Further, since the water-based ballpoint pen uses a batting containing ink, it has the drawbacks of high material cost, high cost, and inconclusive consumption of ink. In addition, under such circumstances, the viscosity was statically high for the purpose of improving each defect, and the viscosity decreased due to the rotation of the tip ball at the time of writing, and the ink had a shear thinning viscosity in which the ink flowed out. Ballpoint pens that use ink are also known. However, a ball-point pen that uses an ink with shear thinning viscosity has a property that ink easily evaporates, and the amount of ink that flows out is large (to increase the writing density). Is increasing. Moreover, 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 (backflow of ink to the rear end of the ink containing tube) is likely to occur due to the weight and impact of the ink. Therefore, it usually prevents the evaporation of the ink at the trailing edge of the ink and moves following the consumption of the ink during writing, but it is a grease-like material that suppresses the backflow of the ink against its own weight and impact. A follower is provided. However, even if the follower is provided, when ink is written directly below the tip ball when writing upwards, the ink head is directly added and a remarkable backflow occurs. Further, if the inner diameter or length of the ink containing tube is increased to increase the amount of ink filled, there is a problem that the backflow phenomenon against impact cannot be supported. If backflow occurs, there is a risk that the inside of the barrel will be contaminated and ink will leak from the ventilation holes provided in the barrel to contaminate hands and clothes. The backflow phenomenon of ink also occurs in oil-based ballpoint pens, but notably in ballpoint pens that use shear-thinning ink. In addition, in a normal ballpoint pen, there is a backlash between the tip of the mouthpiece and the tip, so that the tip sways during writing, which causes a problem of poor writing feeling.

[0003]

[Problems to be solved by the device]

 An object of the present invention is a backflow prevention mechanism for ink caused by upward writing or impact of a ballpoint pen, and can improve the drawbacks and inconveniences of the conventional backflow prevention mechanism. Further, even if there is a gap between the tip of the mouthpiece and the tip, the tip is prevented from rocking to improve the writing feel. It is also an improvement of a ball-point pen that uses ink with so-called shear thinning, which shows a high viscosity statically and the viscosity decreases with the rotation of the ball during writing, causing the ink to flow out. The inner diameter and length of the tube can be increased to increase the ink filling amount and improve the writing life.

[0004]

[Means for Solving the Problems]

 The ball-point pen of the present invention devised to achieve the above object is provided with vertical ribs at a plurality of tapers on the outer surface of the press-fitting cylinder part into which the tip is fitted, and further has a rear end of the press-fitting cylinder part. A fitting cylinder is provided at the rear, and the joint with the ink containing tube fixed to the fitting cylinder is brought into abutment with the front end edge of the shaft cylinder with the rear end edge of the press-fitting cylinder part of the joint, and the vertical rib is attached. A ball-point pen in which the base is fixed to the barrel in a state of abutting against the inner step of the base, and the ball-point pen is provided with a ball receiving seat at the rear part in the joint inner hole and a ball valve is loosely fitted. The chamber is provided at a substantially central portion in the axial direction, a tip fitting hole communicating with the front of the valve chamber and a guide hole communicating with the valve chamber are provided coaxially behind the valve chamber. The shaft hole center with the shaft center of the tip fitting hole appropriately, and at the side of the valve chamber hole a groove or protrusion. When writing, the ball valve loosely fitted in the valve chamber comes into contact with the tip end of the chip in an eccentric manner to form an ink flow section, and the ink is connected to the guide hole and groove to put the ink in the tip. It is made flowable, and has a high viscosity in the ink storage tube statically, and the viscosity decreases due to the rotation of the ball during writing, causing the ink to flow out. The rear end is provided with a follower that has a characteristic of preventing the evaporation of ink and follows the exhaustion of the ink.

[0005]

【Example】

 The embodiment of the present invention shown in FIG. 1 and FIG. 5 has a press-fitting cylinder portion 7 in the first half and a fitting cylinder portion 11 in the latter half, and the outer surface of the press-fitting cylinder portion 7 on the front side is vertically tapered at a plurality of locations. A rib 8 is formed, and an ink storage tube 4 is fixed to the fitting cylinder portion 11 to provide a joint 3. Further, the chip 5 holding the tip ball 5a is press-fitted into the tip fitting hole 10 at the tip of the press-fitting cylinder portion 7 from the rear end side. Further, the back hole 5b of the chip 5 is appropriately eccentrically provided with respect to the chip fitting hole 10.

The joint 3 is integrally formed of elastically deformable synthetic resin, and communicates with the tip fitting hole 10 and has a valve chamber 12 at the rear. A conical ball receiving seat 13 is provided at the rear of the valve chamber 12. A groove portion 15 is provided at a required position on the side surface of the valve chamber hole, and a ball valve 14 is loosely fitted in the valve chamber 12. Further, a guide hole 17 communicating with the ball receiving seat 13 is formed behind the valve chamber 12. The side surface of the valve chamber hole can also be formed as a ridge portion by enlarging the width of the groove portion 15.

A flange portion 16 is provided at the rear end of the press-fitting cylinder portion 7 of the joint 3, and a fitting cylinder portion 11 is extended behind the flange portion 16. A cylindrical ink storage tube 4 is press-fitted and fixed to the outer periphery of the fitting cylinder portion 11 by abutting the tip thereof to the rear end of the collar portion 16, and the inner diameter portion of the ink storage tube 4 is fitted into the guide hole 17 of the joint 3. It is in communication. The ink containing tube 4 is filled with the ink 20 having a shear thinning property that statically has a high viscosity, and the viscosity of the ball is lowered by the rotation of the ball during writing so that the ink can flow out. At the rear end of 20 is filled a grease-like follower 21 that prevents the evaporation of ink and is movable in contact with the ink surface as the ink is consumed. The ink storage tube 4 is made of, for example, a transparent PP resin molded product that suppresses ink evaporation.

Next, the tip 5 of the shaft cylinder 1 is inserted into the joint 3 into the writing portion to which the tip 5 and the ink containing tube 4 filled with ink are fixed, and the front portion of the shaft portion 6 is provided with the collar portion 16 of the joint 3 after the collar portion 16. With the ends abutted against each other, the vertical rib 8 of the press-fitting cylinder portion 7 is abutted against the inner step portion 9 of the mouthpiece 2 in a biting manner, and the mouthpiece 2 is screwed onto the shaft portion 6 of the barrel 1. There is. Further, a ventilation hole communicating with the inner hole portion of the shaft cylinder 1 is provided at an appropriate position of the shaft cylinder 1, or a tail plug 22 press-fitted and fixed to the rear end of the shaft cylinder 1 communicates with the inside of the shaft cylinder 1. A ventilation hole is provided. (Not shown) Further, the barrel 1 is made of a transparent resin molded product so that the amount of ink consumption can be known.

[0009]

[Action]

 FIG. 5 shows a writing state in which the tip 5 is directed downward. At that time, the ball valve 14 abuts on one side of the tip rear end portion 18 in a biased state, and on the other side, a gap through which ink can flow into the tip 5, That is, the ink inflow portion 19 is formed, and the ink that has entered the valve chamber 12 from the ink containing tube 4 through the guide hole 17 passes through the groove portion 15, passes through the ink inflow portion 19, and is guided to the tip of the chip 5. . The ink statically has a high viscosity, but the rotation of the ball at the tip of the tip 5 causes the viscosity to decrease and a large amount of the ink to flow out. 2 and 4 show a state in which the tip 5 is directed upward, and at that time, the ball valve 14 is located in the ball receiving seat 13 of the valve chamber 12 and seals the guide hole 17, so that the writing is directed upward. Even if the ink just below the tip ball 5a is exhausted, the head is not caught by the ink and does not flow backward. Further, in the present invention, the chip 5 is press-fitted into the chip fitting hole 10 of the press-fitting cylinder part 7 of the joint 3, and the vertical rib 8 abuts the inner step part 9 of the base 2 in a biting manner. 5 is locked against the base 2.

[0010]

The structure and operation of the ball-point pen of the present invention are as described above, and the valve chamber is provided in the intermediate portion that communicates the tip and the ink containing tube, and the ball valve loosely fitted in the valve chamber allows upward writing. Since the space between the ink storage portion and the valve chamber is sealed, it is possible to prevent an accident that the ink flows backward and stains the inside of the shaft cylinder, hands, clothes and the like. Also, unlike the conventional example, there is no undercut ridge in the valve chamber to prevent the ball valve from pulling out, so there is no problem in dimensional accuracy or when inserting the ball, and there is no centrifugal force when removing bubbles during ink filling. Also solves the problem of the ball biting. Also, with the vertical ribs formed on the outer surface of the press-fitting cylinder part of the joint abutting against the inner step of the mouthpiece in a biting manner, the mouthpiece is fixed to the shaft cylinder and the joint is loosened by the mouthpiece. , Tip swing is suppressed and the writing feel is good.

[Brief description of drawings]

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

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 an enlarged view of the state in which the tip is facing upward.

FIG. 3 is an enlarged cross-sectional view of a valve chamber hole of a joint.

FIG. 4 is an enlarged cross-sectional view of the valve chamber portion with the tip facing upward.

FIG. 5 is an enlarged cross-sectional view of the valve chamber portion with the tip facing downward.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Shaft cylinder 2 Base 3 Joint 4 Ink storage tube 5 Chip 5a Tip ball 5b Back hole 6 Shaft part 6 Shaft part 7 Press-fitting cylinder part 8 Vertical rib 9 Inner step part 10 Tip fitting hole 11 Fitting cylinder part 12 Valve chamber 13 Ball receiving seat 14 Ball Valve 15 Groove 16 Collar 17 Guide Hole 18 Tip Rear End 19 Ink Inlet 20 Ink 21 Follower 22 Tail Plug

Claims (3)

[Scope of utility model registration request] 1. A ball receiving seat provided at a rear portion of the valve chamber, wherein a valve chamber for loosely fitting a ball valve is provided at a substantially central portion in an axial direction, and a tip fitting hole communicating with the front of the valve chamber is provided. At the rear of the joints, which are coaxially provided with guide holes communicating with the valve chamber,
The axial center of the back hole of the tip is appropriately eccentric with respect to the axial center of the tip fitting hole, and a groove or protrusion is provided at a required location on the side surface of the valve chamber hole. Is a ball-point pen provided with an ink backflow prevention mechanism in which a tip and an ink containing tube are fitted in communication with the guide hole. 2. A press-fitting cylinder part having a tip fitting hole and a valve chamber in its axial center is provided with a plurality of vertical ribs on the outer periphery of the press-fitting cylinder part, and the fitting cylinder is located further rearward of the rear end edge of the press-fitting cylinder part. A section,
A joint made of synthetic resin integrally molded with an ink containing tube fixed to the fitting cylinder is made to abut the front end of the shaft cylinder against the rear end of the press-fit cylinder, and the vertical ribs bite into the inner step of the base. 2. The ball-point pen according to claim 1, wherein the base is fixed to the barrel in a state of abutting against each other. 3. An ink having a so-called shear thinning viscosity, wherein the ink containing tube has a statically high viscosity, and the viscosity is reduced by the rotation of the tip ball during writing to cause the ink to flow out. 3. The ball-point pen according to claim 1, wherein the trailing end of the ink is provided with a follower that has a characteristic of preventing the evaporation of the ink and follows the exhaustion of the ink.