JP3685413B2 - Ballpoint pen - Google Patents

Description

[0001]
[Industrial application fields]
The present invention relates to an improvement of a ballpoint pen using a water-based ink having a so-called shear thinning viscosity, which has a statically high viscosity and the viscosity is lowered by the rotation of the ball during writing and the ink flows out.
[0002]
[Prior art]
Conventionally, so-called oil-based ballpoint pens using high-viscosity inks and so-called water-based ballpoint pens in which ink is incorporated into fibrous batting and the ink is guided to the ballpoint pen tip through an ink guide core are known. Each of them has some drawbacks, but as a simple disadvantage, oil-based ballpoint pens have the disadvantage that the ink is high in viscosity and the writing density and writing density are low. In addition, since the water-based ballpoint pen uses a batting which contains ink, there are disadvantages in that the cost of the member is high and the cost is high and the consumption of the ink is not known. In such a situation, water-based ink having a shear-thinning property that exhibits a high viscosity statically for the purpose of improving the respective disadvantages and has a viscosity that decreases due to the rotation of the ball during writing and the ink flows out. The medium viscosity ballpoint pen used is known. However, the ballpoint pen using the ink having shear thinning viscosity has the property that the ink is easily evaporated and the property that the writing tip is easy to dry, and the ink outflow amount is large (to increase the writing concentration). The diameter of the ink is increased to increase the amount of ink loaded. Further, since the viscosity of the ink is smaller than that of the oil-based ballpoint pen, the flow resistance with respect to the ink containing tube is small. Accordingly, there is a problem that ink leakage (ink flows backward at the rear end of the ink containing tube) easily occurs due to the weight of the ink, impact, or the like, and the tip ball easily jumps out due to drop impact. For this purpose, it normally prevents the ink from evaporating at the trailing edge of the ink and moves following the consumption of the ink during writing. A follower is provided. Further, for the purpose of further improving safety, a cup-shaped float immersed in a follower is disclosed in Japanese Utility Model Publication No. 49-30035.
[0003]
In addition, a recently known medium-viscosity ballpoint pen has a ballpoint pen tip fixed to the tip of a polyacetal joint, and a polypropylene ink storage cylinder fixed to the back of the joint. In general, the water-based ink is filled, and further, a grease-like follower is provided at the trailing end of the ink to prevent evaporation of the ink and to follow the ink consumption due to writing.
Incidentally, the joint is intended to be provided as a member for connecting the chip and the ink storage tube, the temperature change of the chip fixing portion, creep resistance versus aging, stiffness, barrier properties are required for the ink. Further, when an ink backflow prevention structure, which will be described later, is added to the joint, it is required that the molding accuracy is further improved. However, the joint made of polyacetal is inferior in the barrier property against the ink, and the ink in the joint is thickened due to the temperature change and the moisture evaporating over a long period of time, resulting in the problem of blur and writing.
[0004]
Also, a ballpoint pen using a ball valve is known as means for preventing the backflow of ink. As an example of the ball valve, as disclosed in Japanese Utility Model Laid-Open No. 57-193578, a ball is held at the tip, and a ball receiving seat is provided in an inside of a chip cylinder having an ink through hole communicating with the ball at the center. A water-based ballpoint pen that houses a spring member, inserts the linear portion of the spring member into the ink passage hole, and elastically presses the back surface of the ball in the tip direction so that the side periphery of the ball is in close contact with the inner wall of the tip portion. The tip is known. This eliminates the defect that the ink drops back in the axial direction due to standing up or dropping impact (ink out phenomenon due to ink backflow).
As an example of a ball valve, the same applicant discloses a ballpoint pen backflow prevention mechanism provided with a valve chamber in which a ball (ball valve) is loosely fitted in Japanese Utility Model Publication No. 4-52067. This is provided with a required number of ridges that cannot be pulled out in the valve chamber in which the ball valve is loosely fitted with a synthetic resin mouth plastic, and is formed between the ridges during writing. The ink is made to flow to the chip through the gap, and the defect that the ink flows backward is eliminated.
[0005]
[Problems to be solved by the invention]
The object of the present invention is a ball-point pen using aqueous ink which shows a high viscosity statically and has a shear thinning viscosity in which the viscosity is lowered by the rotation of the ball during writing and the ink flows out. Improve writing performance against temperature changes and long-term aging. It is to reliably prevent the backflow of ink and follower due to upward writing, drop impact, or the like.
[0006]
[Means for Solving the Problems]
As a result of repeated improvements based on the above-mentioned knowledge of the prior art, a material that is excellent in creep resistance, rigidity and moldability, has excellent barrier properties against evaporation of water-based ink, and has been found suitable for cost.
In order to achieve the above object, the ballpoint pen of the present invention has a ballpoint pen tip fixed to the tip of the joint and an ink storage cylinder fixed to the back of the joint, and the ink storage cylinder has a high static viscosity. It is filled with water-based ink with so-called shear thinning viscosity that causes the ink to flow out by rotation of the tip ball during writing, and further prevents evaporation of the ink at the rear end of the ink and accompanies writing In the tip provided with a grease-like follower that follows the consumption of ink, the tip has a spring inserted in the inner hole thereof, the rear end of the tip shaft portion is appropriately crimped, and the rear end of the spring is It is provided so that it cannot be pulled out, and an upright rod shaft portion is formed at the tip of the spring. Close to the inner edge of the holder The joint is a resin molded product, and the resin is made of polyphenylene ether (PPE) or polyphenylene oxide (PPO), which has excellent creep resistance and rigidity, and excellent barrier properties against evaporation of water-based ink. It is made of modified PPE or modified PPO modified with polystyrene (PS).
As a further means, the joint is provided with a valve chamber by loosely fitting a ball valve behind the tip fitting hole, and a guide hole having a ball receiving seat at the rear of the valve chamber and communicating with the ink containing cylinder. When the tip side is upward, the ball valve is in close contact with the ball seat and the guide hole is sealed to prevent backflow of ink, and when the tip side is downward, the sealed state is released and the guide hole and valve chamber are passed through. The ink is configured to flow into the chip.
[0007]
【Example】
1 to 3 show a first embodiment of the present invention. First, as shown in the figure, the joint 3 was modified with polystyrene (PS) by polyphenylene ether (PPE) and polyphenylene oxide (PPO), which were excellent in creep resistance and rigidity, and excellent in barrier properties against evaporation of aqueous ink. Molded with modified PPE or modified PPO resin, a press-fit cylinder portion 7 is formed in which a linear or curved rib 8 is provided in a required portion in the first half, and a ring-shaped flange is formed at the rear end of the rib 8 A portion 16 is formed, and the rear end of the rib 8 is connected to be substantially the same as the outer diameter of the flange portion 16. In addition, the fitting cylinder portion 11 is provided in the latter half, and the ink containing cylinder 4 made of polypropylene is fixed to the fitting cylinder portion 11. Further, the tip 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.
[0008]
Further, the joint 3 communicates with the chip fitting hole 10 and is provided with a valve chamber 12 on the rear side. A conical ball seat 13 is provided at the rear of the valve chamber 12. In addition, the valve chamber 12 is appropriately decentered with respect to the axis of the tip insertion hole 10 while being fitted in the inner periphery of the tip insertion hole 10 and is provided at one side of the valve chamber hole. The 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. By the way, the valve chamber 12 does not need to be provided in an eccentric shape if the tip rear end hole is provided in an eccentric state with respect to the tip fitting hole 10.
[0009]
In addition, a cylindrical ink storage cylinder 4 is press-fitted and fixed to the outer periphery of the fitting cylinder portion 11 with its tip abutting against the rear end of the flange portion 16, and the inner diameter portion of the ink storage tube 4 is the guide hole 17 of the joint 3. Communicating with The joint 3 and the ink storage cylinder 4 can be provided integrally. The ink container 4 is filled with an ink 19 having a statically high viscosity and a shear thinning viscosity that allows the ink to flow out by the rotation of the tip ball 5a during writing. A transparent or translucent grease-like follower 20 is filled at the rear end of the ink to prevent the ink from evaporating and to move in contact with the ink surface as the ink is consumed. A colored resin member having a specific gravity substantially equal to that of the follower is immersed in the follower 20. In the embodiment, the colored resin member is a pipe material 21 made of PP resin or the like, and the inner and outer diameters of the follower 20 are filled with the follower 20 so that it is buried in the follower or the rear end of the pipe material 21 is appropriately projected from the rear end of the follower 20. Be positioned. The colored resin member is not limited to the pipe material, and may be a rod material or a ball material, and has an outer diameter that is appropriately smaller than the inner diameter of the ink containing cylinder 4 and is immersed in the follower. The ink storage tube 4 is made of, for example, a transparent PP resin molded product that suppresses ink evaporation. The configuration of the tip 5, the joint 3, and the ink containing cylinder 4 is a ballpoint pen refill. A tail plug 22 is fixed to the rear end of the shaft tube 1.
[0010]
Next, a refill having the tip 5 and the ink containing cylinder 4 filled with ink and the follower fixed to the joint 3 is inserted from the front end of the shaft cylinder 1, and the rear end of the flange portion 16 of the joint 3 is inserted into the front surface of the shaft section 6. The base 2 is brought into contact with the inner step portion 9 of the base 2 in a state where the outer periphery of the linear or curved rib 8 provided at a required portion of the press-fitting cylinder portion 7 is engaged with the edge. It is screwed to the shaft portion 6 of the shaft tube 1. In addition, a notch 6a is provided at a required position at the front end of the shaft portion 6, and the rear end of the flange portion 16 of the joint 3 is in contact therewith. The shaft tube 1 is made of a transparent resin molded product so that the amount of ink consumed can be understood. With the above configuration, the shaft cylinder 1 is formed through the gap between the tip hole protruding the tip 5, the inner periphery of the base 2, the gap formed between the rib 8 and the rib 8 of the press-fitting cylinder portion 7, and the notch 6 a of the shaft portion 6. An air passage communicating with the inner hole 1a is formed. If necessary, the inner hole 1a communicates with the outside air, and a vent hole or a tail plug 22 or a vent hole between the tail plug and the shaft cylinder is provided on the side surface of the shaft cylinder 1. If the ballpoint pen is disposable, the base 2 and the shaft tube 1 are not necessary, and the refill itself becomes the writing shaft of the ballpoint pen.
[0011]
By the way, the cap 23 fitted to the shaft tip has the clip 24 positioned on the outer peripheral side surface thereof and presses the rear end cylindrical portion 30 to the rear end hole. Further, a vent hole 29 passes through the rear end of the cylindrical portion 30. Further, a cylindrical inner cap 25 having a small chamber 27 is provided behind the inner hole of the cap 23, and the inner cap 25 is integrally formed with a required number of ribs 26 between the inner hole portion. As described above, an air passage communicating from the cap insertion port to the air hole 29 is formed between the ribs. There are various means for forming the air holes, and the structure is not particularly limited. Further, the cap 23 is provided with an engaging portion 32 at the insertion port, and is detachably attached to the engaging portion 31 provided in the shaft tube 1. Note that the engaging portion is configured by engagement of a commonly used convex portion or concave portion. In addition, a seal plug body 28 made of a non-liquid-absorbing non-continuous cell elastic body is fixed to the tip of the small chamber 27 of the inner cap 25, and the tip of the tip 5 and the base 2 is closely fitted in the small chamber 27. The tip ball 5a is pressed against the seal plug 28 as appropriate.
[0012]
4 and 5 show a second embodiment of the present invention. First, as shown in the figure, the joint 32 is formed in the same manner as in the first embodiment. Only the differences will be described below.
First, 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 through which ink can flow. Further, the spring 31 is inserted into the inner hole of the tip 5, the rear end of the tip shaft portion 5c is appropriately crimped, and the rear end of the spring 31 is provided so as not to be extracted. Further, an upright rod shaft portion 31a is formed at the tip of the spring 31, and the tip of the rod shaft portion 31a abuts against the rear end of the tip ball 5a in a pressing manner. The tip ball 5a is brought into close contact with the inner edge of the ball holding portion (formed by caulking or the like) of the chip 5 by the pressing.
[0013]
Thus, when the tip side is facing downward, the ball valve 33 comes into contact with the crimped portion 5d at the rear end of the tip, and the ink passes through the guide hole 36, the valve chamber 34, the groove portion 35, and the inner hole of the tip 5, and the rear end of the tip ball 5a. Inflow is possible.
[0014]
[Action]
In the first embodiment,
With the tip 5 facing upward, as shown in FIG. 2, the ball valve 14 is in contact with the ball receiving seat 13 of the valve chamber 12 and seals the guide hole 17, so that the ink flows backward with upward writing. Can be prevented. FIG. 2 shows a state in which the cap 23 is fixed to the shaft tip. Since the tip of the tip 5 is in pressure contact with the sealing plug 28, there is no problem that the tip ball 5a jumps out due to a drop impact.
In addition, since the ball valve 14 is loosely fitted in the valve chamber 12 in an appropriately eccentric relationship with the tip rear end hole 18, there is no problem that the ball valve bites by centrifugation after ink filling in the manufacture of the refill. Even if the ball valve 14 abuts against the chip rear end portion 18, the ball valve is biased and an ink inflow portion to the chip 5 is secured.
The ink container 4 is made of polypropylene with excellent barrier properties for ink evaporation, and the joint 3 is also a resin with excellent barrier properties, so that the temperature of the ink and the ink evaporates over a long period of time, thereby suppressing the occurrence of squeezing and writing distortion. Is done.
[0015]
In the second embodiment,
FIG. 1 shows a state before writing with the tip 5 facing downward. At that time, the ball valve 33 comes into contact with the rear end of the tip 5 and the guide hole 36 is opened. The ink that has entered the valve chamber 34 from the ink containing tube 4 through the guide hole 36 is guided to the rear end of the tip ball 5 a through the groove 35. In this state, the tip ball 5a is brought into close contact with the inner edge of the chip holding portion by pressing of the rod shaft portion 31a, so that direct current of ink is prevented. Further, the tip ball 5a is slightly retracted by the writing pressure, so that a gap is formed and the ink can flow out. By writing, the tip ball 5a is rotated to reduce the viscosity, and a large amount of ink flows out. High writing is possible.
[0016]
Directly below the tip ball 5a, there is a channel 5b (a tip ball receiving seat having a plurality of ink inflow grooves penetrating toward the chip inner hole), and the rod shaft portion 31a passes through the center hole of the channel 5b. To do. The ink in the chip is guided directly under the tip ball through a gap between the ink inflow groove and the center hole and the rod shaft portion 31a.
[0017]
Further, when the tip 5 is directed upward, the ball valve 33 is in close contact with the ball receiving seat 37 of the valve chamber 34 and seals the guide hole 36. Therefore, even if the ink immediately below the tip ball 5a disappears by writing upward, the ink flows backward. do not do. Therefore, when the chip 5 is turned downward, ink can immediately flow out, and dripping is prevented by writing. (By the way, in the structure that does not have a ball valve, the ink works in the reverse flow direction when writing upward, so that air is trapped in the tip, and the ink does not follow immediately when writing downward. Entrainment is accumulated.)
[0018]
Moreover, since the tip ball 5a is always in close contact with the inner edge of the chip holding portion, writing tipping is prevented by drying the tip portion. In addition, the joint action of the tip ball 5a and the ball valve 33 prevents air entrainment even if an upward writing or impact is applied, thereby preventing writing squeezing.
[0019]
【The invention's effect】
The configuration and operation of the ballpoint pen of the present invention are as described above, and the joint is excellent in creep resistance, rigidity, and moldability, so there is no problem in strength and accuracy, and the barrier property against evaporation of water-based ink. Since it is excellent, it can suppress the occurrence of squeezing and writing stagnation against temperature changes and long-term aging.
In addition, the ball valve loosely fitted in the valve chamber can prevent upward flow of ink due to upward writing or impact, thereby preventing an accident in which the shaft tube, hands, clothes, etc. are soiled. Further, when the second embodiment is used, the tip ball is in close contact with the inner edge of the chip holding portion except when writing, so that direct current is prevented when the tip ball is placed downward.
Also, since ink follows immediately after upward writing or impact, dripping is prevented.
[Brief description of the drawings]
FIG. 1 is a longitudinal sectional view showing an entire ballpoint pen according to a first embodiment of the present invention, and shows a state in which a tip faces upward.
FIG. 2 is an enlarged cross-sectional view of the front half of the ballpoint pen according to the first embodiment, showing a state in which the tip is directed upward.
FIG. 3 is an enlarged cross-sectional view of the rear half of the ballpoint pen according to the first embodiment.
FIG. 4 is a longitudinal sectional view of an essential part of a ballpoint pen according to a second embodiment of the present invention, showing a state in which a tip is directed downward;
FIG. 5 is an enlarged view of the valve chamber portion of the joint shown in FIG. 4 in cross section.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Shaft cylinder 1a Inner hole 1b Locking groove 1c Step part 1d Step part 1e Locking groove 2 Base 3 Joint 4 Ink storage cylinder 5 Tip 5a Tip ball 5b Channel 5c Shaft part 5d Caulking part 6 Shaft part 6a Notch 7 Press-fit cylinder part 8 Rib 9 Inner step portion 10 Tip fitting hole 11 Fitting cylinder portion 12 Valve chamber 13 Ball receiving seat 14 Ball valve 15 Groove portion 16 Hook portion 17 Conducting hole 18 Tip rear end hole 19 Ink 20 Follower 21 Follower rod 22 Tail plug 23 Cap 23a Locking protrusion 23b Locking protrusion 23c End 24 Clip 25 Inner cap 26 Rib 27 Small chamber 28 Seal plug body 29 Vent 30 Tube 31 Spring 31a Rod shaft 32 Joint 33 Ball valve 34 Valve chamber 35 Groove 36 Guide hole 37 Ball seat

Claims (2)

The ballpoint pen has a ballpoint pen tip fixed to the tip of the joint, and an ink storage cylinder fixed to the rear of the joint. The ink storage cylinder has a statically high viscosity, It is filled with water-based ink with so-called shear thinning viscosity that causes the viscosity to drop by rotation and the ink flows out, and further prevents the ink from evaporating at the trailing edge of the ink and follows the consumption of ink accompanying writing In what is provided with a follower,
The tip has a spring inserted in its inner hole, and the rear end of the tip shaft portion is appropriately crimped so that the rear end of the spring cannot be pulled out, and an upright rod shaft portion is provided at the front of the spring. The tip of the rod shaft portion is pressed against the rear end of the tip ball so that it is in close contact with the inner edge of the ball holding portion of the chip, and the joint is a resin molded product. A ballpoint pen characterized in that the resin is made of modified PPE or modified PPO obtained by modifying polyphenylene ether (PPE) or polyphenylene oxide (PPO) with polystyrene (PS). The joint is provided with a ball valve loosely fitted behind the tip fitting hole and a valve chamber, and a rear portion of the valve chamber having a ball receiving seat and communicating with the ink containing cylinder is provided with the tip side facing upward. Sometimes the ball valve is in close contact with the ball seat and the guide hole is sealed to prevent the backflow of ink. The ballpoint pen according to claim 1, wherein the ballpoint pen is configured as described above.

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