JP2604349Y2 - Ballpoint pen - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement of a ballpoint pen having a mechanism for preventing ink from flowing backward.

[0002]

2. Description of the Related Art The applicant of the present invention discloses, in Japanese Utility Model Publication No. 4-52067, a mechanism for preventing ink from flowing back from a ballpoint pen provided with a valve chamber in which a ball valve is loosely fitted. In this valve, a required number of ridges are provided in a valve chamber in which a ball valve is loosely fitted with a synthetic resin mouth plug so that the ball valve cannot be pulled out, and a gap formed between the ridges during writing. The ink flows through the chip to the chip.

[0003] A mouth plastic is obtained by injection molding, but it is difficult to obtain dimensional accuracy due to an undercut at the time of mold release, and to prevent damage to the ridge by inserting the ridge when inserting a ball valve. Necessary and cumbersome. Also at the time of manufacture, but is centrifuged to defoaming bubbles engulfed after ink filling, there is a disadvantage that the time the ball valve bites ball valve is in the ridges by centrifugal force is fixed.

Heretofore, there has been known a so-called water-based ballpoint pen in which ink is incorporated in a so-called oil-based ballpoint pen using high-viscosity ink and a fibrous batting, and the ink is guided to a ballpoint pen tip via an ink guide core. . Respectively,
Although there are some drawbacks, an obvious drawback is that oil-based ballpoint pens have a drawback due to the high viscosity of the ink and a low writing density.

[0005] The water-based ball-point pen uses a batting for incorporating the ink, so that the material cost increases and the cost increases.
There is a disadvantage that the ink consumption state cannot be determined. Under such circumstances, a ballpoint pen using ink having a shear-thinning viscosity, which exhibits a high viscosity statically for the purpose of improving each of the drawbacks, and in which the viscosity decreases when the ball rotates during writing and the ink flows out. Is also known.

However, a ball-point pen using an ink having a shear thinning property has a property that the ink is apt to evaporate, so that a large amount of the ink flows out in order to increase the writing density, and therefore the diameter of the ink storage tube is increased. Then, the mounting amount of ink is increased. Further, since the viscosity of the ink is smaller than that of the oil-based ball-point pen ink, the flow resistance to the ink storage tube is small. Accordingly, ink leakage, in which the ink flows backward at the rear end of the ink storage tube, easily occurs due to the weight and impact of the ink.

For this reason, usually, the ink is prevented from evaporating at the rear end of the ink and moves following the consumption of the ink at the time of writing. However, the backflow of the ink due to its own weight or impact is suppressed. A grease-like follower is provided.
However, even when the follower is provided, when ink is written immediately below the ball of the chip when writing upwards, the ink head is added directly, causing a significant backflow.

Further, if the inner diameter and length of the ink containing tube are increased to increase the ink filling amount, there is a problem that the backflow phenomenon due to the impact cannot be supported. When the backflow occurs, there is a danger that the inside of the barrel will be soiled and ink will leak from the air holes provided in the barrel to stain the hands and clothes. The ink reflux phenomenon also occurs with an oil-based ball-point pen, but it occurs remarkably in the case of a ball-point pen using a shear-thinning ink. In addition, a normal ballpoint pen has a problem that the tip oscillates during writing and the writing feel is poor because there is play between the tip end of the base and the tip.

[0009]

SUMMARY OF THE INVENTION A first object of the present invention is a mechanism for preventing a backflow of ink caused by upward writing or impact of a ballpoint pen, and provides a ballpoint pen in which the drawbacks and disadvantages of the conventional backflow prevention mechanism have been improved. Is to do.

A second object of the present invention is to provide a ballpoint pen that prevents the tip from swinging even if there is a gap between the tip end of the base and the tip, thereby improving the writing feel.

A third object of the present invention is to improve a ballpoint pen using so-called shear-thinning ink, which exhibits a high viscosity in a static state, and the viscosity decreases by rotation of the ball during writing, causing ink to flow out. By doing so, the inner diameter and length of the ink storage tube are increased to increase the ink filling amount, and to provide a ballpoint pen with a long writing life.

[0012]

The inventor of the present invention has conducted intensive studies to solve the above-mentioned problems. As a result, the center axis of the ball valve seat is eccentric with the center axis of the chip fitting hole, and the valve chamber is eccentric. It has been found that the solution can be solved by providing a groove on one side of the hole, and the problem of the tip rocking in the tip end of the mouthpiece is provided with a tapered vertical rib on the outer surface of the press-fitting cylindrical portion for fitting the chip, The present inventors have found that this can be solved by making the inner step of the base difficult to fix, and completed the present invention.

That is, the present invention is as follows. (1) A ball valve receiving seat is provided at a rear portion, and a valve chamber for loosely fitting a ball valve is provided at a substantially central portion in the axial direction. A chip fitting hole is provided in front of the valve chamber, and a ball is provided behind the valve chamber. In a ballpoint pen having a joint provided with a guide hole in the center of the valve seat,
The axis of the ball valve seat is eccentric with respect to the axis of the chip fitting hole, and a groove is provided on one side of the valve chamber hole wall. In a writing state, one end of the ball valve is part of the chip end. The contact point and the ball valve at this time, which is extended to near the tip end, is supported by the sliding surface of the ball valve on the upper surface of the groove portion which is spaced apart, and the center of the ball valve has a chip fitting hole. It is configured such that the eccentric state with respect to the axis is maintained, and ink from the groove portion is allowed to flow into the chip, and the chip is fitted into the chip fitting hole of the joint, and the ink storage tube is fitted to communicate with the guiding hole, respectively. Ballpoint pen with ink backflow prevention mechanism

(2) Vertical ribs are provided at a plurality of places in a tapered shape on the outer periphery of a press-fitting cylindrical portion forming a front portion of a joint having a chip fitting hole and a valve chamber, and a flange portion is provided on a rear end edge of the press-fitting cylindrical portion. In the state where the vertical rib of the joint provided with the fitting tube portion for fitting the ink tube and the shaft tube in the rear portion is bitingly engaged with the step portion in the base of the chip, the base is fixed to the shaft tube. The previous item (1)
The described ballpoint pen.

(3) The ink storage tube is filled with ink having a so-called shear thinning viscosity, which has a high viscosity in a static state, and a viscosity is reduced by rotation of a ball during writing to facilitate outflow. The ballpoint pen according to the above (1) or (2), further comprising a follower provided at a rear end thereof for preventing evaporation of the ink and following the consumption of the ink.

In the present invention, the center axis of the conduit communicating with the ink storage tube of the ball valve receiving seat is appropriately eccentric with respect to the center axis of the chip fitting hole while being fitted in the inner periphery of the chip fitting hole. It is provided in. Therefore, when the ball-point pen faces upward and the ball valve is seated in the ball-valve receiving seat, the center of the ball valve is characterized by being slightly offset from the center axis of the chip fitting hole.

A groove is provided on one side of the valve chamber hole which is shifted, and one end of a ball valve loosely fitted into the valve chamber in a writing state abuts a part of the tip end eccentrically. The eccentricity of the center of the ball valve with respect to the axial center of the chip fitting hole is supported by the contact point and the ball valve at this time, which is extended to the vicinity of the tip end, and is supported by the sliding surface of the ball valve on the upper surface of the groove which is maintained at an interval. The state is maintained, the ink from the groove is configured to be able to flow into the chip, and the ink storage tube is connected to a conduit,
The ink can flow into the chip by communicating with the groove.

A plurality of tapered vertical ribs are provided between the press-fitted cylindrical portion of the joint and the outer rear end flange.
When a mouthpiece (also called a mouthpiece when made of plastic) is screwed into the barrel, the vertical ribs cut into the inner step of the mouthpiece so that the tip does not swing during writing.

The ink storage tube is filled with ink having a shear thinning property. A follower is provided at the rear end of the ink to prevent evaporation of the ink and follow the ink as it is consumed.

[0020]

The present invention will be described in more detail with reference to the following examples, but the present invention is not limited to these examples. An embodiment of the present invention will be described with reference to FIGS. 1 to 6. FIG. 1 is a vertical cross-sectional view showing the whole ballpoint pen, and shows a state in which a chip is directed upward.
FIG. 2 is a vertical cross-sectional view of the joint, which is the main part.

Referring to FIG. 2, a press-fit cylinder 7 is provided in the first half of the joint 3, a flange 16 is provided in the rear, and a fitting cylinder 11 is provided in the second half. A plurality of tapered vertical ribs 8 are formed on the outer surface of the front press-fitting cylinder 7 at a plurality of locations around the front side. The ink storage tube 4 is fixed to the fitting tube portion 11, and the shaft tube 1 is fitted to the outer periphery thereof. The tip 5 holding the ball at the tip is press-fitted into the tip fitting hole 10 at the tip of the press-fitting cylinder 7.

The joint 3 is made of an elastically deformable synthetic resin and is integrally formed. A valve chamber 12 is provided at the rear in communication with the chip fitting hole 10. The valve chamber 12
In a state where the hole is accommodated in the inner periphery of the chip fitting hole 10, the axis of the hole of the ball valve receiving seat 13 at the rear end is appropriately eccentric (eccentric S) with respect to the axis of the chip fitting hole 10, and the valve chamber hole is formed. A groove 15 is provided on one side. A ball valve 14 is loosely fitted in the valve chamber 12. A guide hole 17 is formed in the center of the ball valve seat 13 so as to communicate with the inside of the rear ink storage tube.

A flange 16 is provided at the rear end of the press-fit tube 7 of the joint 3, and a fitting tube 11 extends behind the flange 16. A cylindrical ink storage tube 4 is press-fitted and fixed on the outer periphery of the fitting cylindrical portion 11 with its front end abutting on the rear end of the flange portion 16.
Is in communication with The ink container 4 is filled with an ink 20 having a high viscosity statically, and having a shear-thinning viscosity that allows the ink to flow out by decreasing the viscosity by rotation of the ball during writing (FIG. 1). A grease-like follower 21 is provided at the rear end of the ink 20 so as to prevent evaporation of the ink and to move in contact with the ink surface as the ink is consumed.
Is filled. The ink storage tube 4 is made of, for example, a transparent polypropylene resin molded product which suppresses evaporation of the ink.

From the tip end of the shaft cylinder 1, a writing portion in which the tip 5 and the ink containing tube 4 filled with ink are fixed is inserted into the joint 3, and the rear end edge of the flange 16 of the joint 3 is attached to the front surface of the shaft portion 6. Then, the vertical ribs 8 of the press-fitting cylinder 7 are attached to the inner step 9 of the base 2.
The base 2 is screwed to the shaft portion 6 of the shaft cylinder 1 in a state where the base 2 is bitingly contacted. Further, a ventilation hole communicating with the inner hole portion is formed at an appropriate position of the barrel 1 or a tail plug 22 press-fitted and fixed to the rear end of the barrel 1 is provided with a ventilation hole communicating with the inside of the barrel. (Not shown).

[0025]

FIG. 6 shows a writing state in which the tip 5 is turned downward. At this time, the ball valve 14 abuts on a part of the tip end 18 in a state where it is biased to one side, and this contact point and this contact point The center of the ball valve is always eccentric with respect to the axis of the chip fitting hole, supported by the sliding surface with the ball valve on the upper surface of the groove that extends to the vicinity of the tip end. Is held. On the other hand, a gap through which ink can flow into the chip 5, that is, an ink inflow portion 19 is formed, and the ink that has entered the valve chamber 12 from the ink storage tube 4 through the guide hole 17 passes through the groove portion 15 and passes through the ink inflow portion 19. And is guided to the tip of the chip 5. Although the ink has a high viscosity statically, the rotation of the ball at the tip of the chip 5 lowers the viscosity, causing a large amount of ink to flow out. FIGS. 2 and 5 show a state in which the tip 5 is turned upward. At this 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 ball valve 14 is written upward. Even if the ink directly below the ball of the chip runs out, the ink does not clog the head and does not flow backward. Further, in the present invention, the tip 5 is pressed into the tip fitting hole 10 of the press-fitting cylindrical portion 7 of the joint 3 and the vertical rib 8 abuts the inner step 9 of the base 2 in a biting manner. The cap 2 is rattled.

[0026]

The configuration and operation of the ballpoint pen according to the present invention are as described above. A valve chamber is provided at an intermediate portion communicating the chip and the ink storage tube, and ink is written upward by a ball valve loosely fitted in the valve chamber. Since the space between the storage section 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. Further, since there is no undercut ridge in the valve chamber to prevent the ball valve from being pulled out as in the conventional example, there is no problem with dimensional accuracy or when inserting the ball valve, and when removing bubbles during ink filling. The problem of the ball biting by centrifugation is also solved. In addition, in a state where the vertical ribs formed on the outer surface of the fitting press-fitting cylindrical portion are in contact with the inner step portion of the base in a biting manner, the base is fixed to the shaft cylinder and the joint is rattled by the base, The swing of the tip is suppressed and the brush feel is good.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing an entirety of a ballpoint pen according to an embodiment of the present invention, showing a state in which a chip is directed upward.

FIG. 2 is a longitudinal sectional view of a main part of the ballpoint pen according to the embodiment of the present invention, and is an enlarged view of a state where a chip is directed upward;

FIG. 3 is a sectional view of the joint used in the present invention.

FIG. 4 is a sectional view of the joint AA shown in FIG. 3;

FIG. 5 is an enlarged cross-sectional view of a valve chamber portion in a state where a chip is directed upward.

FIG. 6 is an enlarged cross-sectional view of a valve chamber portion in a state where a tip is directed downward.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Shaft cylinder 2 Base 3 Joint 4 Ink accommodating tube 5 Chip 6 Shaft part 7 Press-fitting cylinder part 8 Vertical rib 9 Inner step part 10 Chip fitting hole 11 Fitting cylinder part 12 Valve room 13 Ball receiving seat 14 Ball 15 Groove part 16 Flange Part 17 Guide hole 18 Tip end 19 Ink inflow part 20 Ink 21 Follower 22 Tail plug S Eccentricity

Claims (3)

(57) [Scope of request for utility model registration] A ball valve receiving seat is provided at a rear portion, and a valve chamber for loosely fitting a ball valve is provided at a substantially central portion in an axial direction, and a chip fitting hole is provided in front of the valve chamber and at a rear portion of the valve chamber. in the ballpoint pen having a joint provided with a bore hole in a central portion of the receiving seat ball valve, the axis of the ball valve seat causes the eccentric to the axis of the tip fitting hole, on one side of the Benshitsuana wall Provide a groove ,
In writing state, a part of the ball valve is in contact with the <br/> part of the tip end portion, and the contact, this time the ball valve, and held apart extending to near the chip end groove upper surface of the ball valve And the eccentric state of the center of the ball valve with respect to the axis of the chip fitting hole is maintained, and the ink from the groove can flow into the chip. A ball-point pen having an ink backflow prevention mechanism formed by fitting a chip into the chip fitting hole, and fitting the ink storage tube to the conductive hole. 2. A vertical rib is provided at a plurality of places in a tapered shape on an outer periphery of a press-fitting cylindrical portion forming a front portion of a joint having a chip fitting hole and a valve chamber, and a flange portion is provided on a rear end edge of the press-fitting cylindrical portion. Stop the base with respect to the shaft cylinder in a state where the vertical rib of the joint provided with a fitting cylinder part for fitting the ink storage tube and the shaft cylinder is engaged with the step in the base of the chip in a biting manner. The ballpoint pen according to claim 1, which is worn. 3. An ink storage tube is filled with ink having a so-called shear thinning viscosity, which has a high viscosity in a static state and a viscosity lowers by rotation of a ball at the time of writing so that the ink easily flows out. 2. A follower having characteristics to prevent evaporation of ink at an end thereof and following the ink consumption.
Or the ballpoint pen according to 2.