JP2009107353A - Ball-point pen - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a ball-point pen that, regardless of a type of ink, can further release gas to be defoamed in an assembling process and that can prevent a ball-point pen from degrading on account of remaining gas bubbles. <P>SOLUTION: The ball-point pen includes a ball-point pen chip 1 having a writing ball 2 to be a writing part, an ink storing tube 8 with an ink 9 stored inside, and a joint 10 for connecting the ball-point pen chip 1 to the ink storing tube 8. The joint 10 has a flange 3a that comes in contact with the end of the ink storing tube 8, wherein a thinned part 3b is formed in the flange 3a. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a ball-point pen, and more particularly, to a ball-point pen including a ball-point pen tip having a writing ball serving as a writing unit, an ink storage tube that stores ink therein, and a joint that connects the ball-point pen tip and the ink storage tube.

As a member constituting the ballpoint pen, a joint for connecting the ink containing tube containing the ink and the ballpoint pen tip and preventing ink backflow is used.
Conventionally, considering the cost and manufacturing aspects, many parts are composed of one part. For example, the ball valve is eccentric from the joint axis on the assumption that it has an ink backflow prevention mechanism. An eccentric type configured so as not to occlude can be mentioned. This eccentric type ink backflow prevention mechanism is known to function without problems in general color inks such as black, red, and blue used for normal character writing.

On the other hand, in recent years, special inks have been developed using pigments of metals and metal compounds such as gold and pastel colors in addition to the general colors. In these special inks, the specific gravity of the pigment is much larger than the specific gravity of the water or organic solvent constituting the ink, and the particle diameter of the pigment is about 0.3 μm to 3 μm in order to ensure the color developability of the particles. A relatively large one is used. For this reason, the special ink has a higher ink viscosity in order to stabilize and disperse the pigment in the ink.
For this reason, when the special ink is used for a one-component joint that is normally used for a ballpoint pen on which general color ink is mounted, there is a problem that ink clogging is likely to occur because the ink flow path is narrow.

Also, with the general color ink, the ink flow path is limited in the joint composed of one part due to the increase in the amount of ink outflow due to the increase in the size of the ballpoint pen tip writing ball. There was another problem in that it was not in time and scumming occurred.
In order to solve such a problem, the applicant of the present invention discloses a ballpoint pen (writing instrument) in Patent Document 1 in which an improvement is made to prevent an operation delay of the ink backflow prevention mechanism in the joint.

FIG. 3 is a cross-sectional view of the tip of the ballpoint pen disclosed in Patent Document 1. As shown in FIG. As shown in FIG. 3, an ink containing tube 58 filled with ink 60 is fitted to the upper end of the joint 50. A ball-point pen tip 51 is fitted to the lower end of the joint 50, and a writing ball 52 is rotatably fitted to the tip of the ball-point pen tip 51.
The joint 50 includes a joint body 53, a check ball 57 that is loosely fitted therein and functions as a valve, and a seal piece 56 fitted to the upper end of the joint body 53.
An ink flow path 56b is formed through the seal piece 56 along the pen axis.

Here, the specific gravity G of the check ball 57 is set to be smaller than a value that does not move in the joint body 53 due to the check ball 57 being too heavy and larger than three times the specific gravity W of the ink 60. ing.
That is, by setting the specific gravity G of the check ball 57, the check ball 57 is smoothly moved according to the inclination of the ballpoint pen.
Accordingly, when the check ball 57 is moved and positioned on the receiving protrusion 54 formed on the pen tip side, a flow path of the ink 60 to the pen tip is formed by a groove or the like, and the ink 60 is applied to the pen tip. It is configured to flow. On the other hand, when the check ball 57 moves to the pen rear end side, the ink flow path is blocked by the seal surface 55 in the joint main body 53 and the back flow of the ink 60 is prevented.
According to the configuration disclosed in Patent Document 1, it is possible to form a large ink flow path, and not only the general color ink but also the special ink can be applied.

JP-A-10-236063 (page 3, right column, line 30 to page 4, left column, line 44, Fig. 1)

By the way, products such as ballpoint pens are assembled at high speed by an automatic machine in order to increase productivity.
Therefore, when assembling a joint composed of a plurality of parts as shown in Patent Document 1 at high speed, it is necessary to release gas (air) existing between the parts in order to easily insert the parts. In other words, it is necessary to prevent the gas (air) in the space (valve space) in which the check ball 57 is loosely fitted from being rapidly compressed.
For this reason, a minute gap is formed at a connection portion between the parts constituting the joint 50. Further, by forming such a minute gap, the contact area between the joint body 53 and the seal piece 56 can be further reduced, and the pressure input can be reduced.

This will be described in more detail with reference to FIG. 4 shows an enlarged cross-sectional view of the tip of a conventional ballpoint pen having the same members as the ballpoint pen shown in FIG. 3, and FIG. 5 shows a CC cross-sectional view of FIG.
As shown in FIGS. 4 and 5, groove portions 56 a are formed on the left and right sides of the seal piece 56 along the pen axis direction.
That is, the gap G <b> 2 is formed between the seal piece 56 and the joint body 53 by forming the groove 56 a. As a result, when the seal piece 56 is inserted and fitted into the joint body 53, the gas existing between the two parts is discharged to the outside.

On the other hand, after fitting the joint 50 into the ink containing tube 58, the ink 60 is contained in the valve space S2. At this time, in order to remove the gas (air) existing in the joint 50 and replace it with the ink 60, centrifugal separation is performed. Foam treatment is performed.
At this time, the centrifugal conditions are set so that a pigment having a high specific gravity and a large particle size does not settle on the ball-point pen tip 51 side. However, since a large centrifugal force cannot be applied, the gas existing in the gap G2 escapes. There was a case where it remained without cutting.
Moreover, since the collar part 53a formed in the coupling main body 53 is formed in thickness compared with the other site | part, the sink part 53b is formed by shrinkage | contraction. For this reason, the gap G3 is generated by the sink portion 53b in a state where the seal piece 56 is fitted to the joint body 53.
That is, in addition to the gap G2, gas (air) existing in the gap G3 may remain without being completely removed in the centrifugal defoaming process.

When the gas (air) remains in the joint 50 in this way, it mixes into the ink 60 during use, and this becomes a nucleus and grows into large bubbles over time, and as shown in FIG. In some cases, bubbles B were present in the ink 60. When the bubbles B are generated in this way, not only the appearance is deteriorated, but the ink is divided and the ink cannot be used up to the end. Further, when the small bubbles are dispersed in the ink instead of the large bubbles that divide the ink 60 as in the case of the bubbles B, there are cases where the ink comes out poorly and rubs.
That is, there is a technical problem that as the minute space in the joint increases, the residual gas (air) increases and the possibility of deteriorating the quality of the ballpoint pen increases.

The present invention has been made under the circumstances as described above, and in order to solve the above-described problems, the applicant of the present invention has intensively studied further improvement of the joint structure shown in Patent Document 1, The present invention has been reached.
That is, the present invention provides a ballpoint pen that can extract more gas to be defoamed in the assembly process regardless of the type of ink, and can further suppress the deterioration of the quality of the ballpoint pen due to the residual gas. Objective.
In particular, the present invention provides a ballpoint pen that can suppress residual gas remaining in the gap G3 generated by the sink portion in a state in which a seal piece is fitted to the joint body, and can further suppress deterioration in quality of the ballpoint pen due to the residual gas. With the goal.

  In order to solve the above-mentioned problems, a ballpoint pen according to the present invention connects a ballpoint pen tip having a writing ball as a writing portion, an ink containing tube containing ink therein, and the ballpoint pen tip and the ink containing tube. A ballpoint pen including a joint, wherein the joint has a collar portion that contacts an end portion of the ink containing tube, and a meat stealing section is formed in the collar portion.

Thus, by forming a meat stealing part in a collar part, the site | part formed thickly in a joint can be eliminated. That is, the occurrence of sink marks due to heat shrinkage after molding can be suppressed.
Therefore, residual gas (air) due to the sink portion can be suppressed, gas can be discharged and replaced with ink more reliably in the centrifugal defoaming process, and deterioration of the quality of the ballpoint pen due to the residual gas can be further suppressed. Can do.

The joint is characterized in that the ink flow path is closed with the tip of the ball-point pen tip facing upward.
By configuring the joint in this manner, ink leakage during non-writing can be prevented.
Further, in the component constituting the joint, the surface on the ball-point pen tip side of the protruding portion that protrudes toward the ink flow path has an inclined surface that inclines from the ball-point pen tip side toward the ink storage tube toward the center portion. It is desirable that it be formed.
By providing the inclined surface in this way, the gas in the joint can be easily discharged to the ink containing tube side in the centrifugal defoaming process, and the residual gas in the joint can be eliminated.

Incidentally, parts constituting the joint, the oxygen permeability at 23 ° C. ^{is, 200 (cm 3 / m 2} / 24hr, 25μm) is preferably formed by the following materials. When the oxygen permeability is greater than ^{200 (cm 3 / m 2 /} 24hr, 25μm), easily the gas from the outside penetrates through the joint, bubbles in the ink tends to grow. That is, when the material conditions are satisfied, it is possible to suppress the external gas from penetrating through the parts constituting the joint and entering the ink.

  As is clear from the above description, according to the present invention, the gas to be discharged in the assembly process can be extracted regardless of the type of ink, and the deterioration of the quality of the ballpoint pen due to the residual gas can be prevented.

FIG. 1 is a cross-sectional view showing an embodiment of a tip portion of a ballpoint pen according to the present invention. FIG. 2 is a cross-sectional view taken along the line AA in FIG. FIG. 3 is a cross-sectional view of the tip of a ballpoint pen shown in the prior art. FIG. 4 is an enlarged cross-sectional view of the tip of a conventional ballpoint pen having the same members as the ballpoint pen shown in FIG. FIG. 5 is a CC cross-sectional view of FIG. 6 is an overall cross-sectional view of the ballpoint pen of FIG.

An embodiment according to the present invention will be described below with reference to FIGS. 1 and 2. FIG. 1 is a cross-sectional view showing an embodiment of the tip portion of the ballpoint pen according to the present invention. FIG. 2 is a cross-sectional view taken along the line AA in FIG.
A ballpoint pen 20 shown in FIG. 1 is made of a transparent or translucent resin-made ink storage tube 8, a joint 10 that is press-fitted into the tip of the ink storage tube 8, and a press-fitting into the tip of the joint 10. A writing instrument of a direct liquid type refill composed at least of a ballpoint pen tip 1 fitted therein.

The ink containing tube 8 contains, for example, an aqueous medium viscosity ink (hereinafter referred to as ink) 9, and a grease-like follower (not shown) that hardly volatilizes is incorporated behind the ink containing tube 8 to prevent ink leakage. is doing.
The ball-point pen tip 1 has a circumferential crimping portion 1a formed therein, thereby holding a writing ball 2 serving as a writing portion at the tip. The writing ball 2 is loosely fitted by the caulking portion 1a so as to be able to supply an ink amount necessary for writing to a writing target.

The joint 10 includes a plurality of components, that is, a joint body 3 having a through-hole formed in the pen axis direction, a check ball 7 positioned on the receiving projection 4 formed in the joint body 3 at the time of writing, The seal piece 6 is press-fitted and fixed from the upper end of the joint body 3. An ink flow path I is formed from the ink storage tube 8 toward the ballpoint pen tip 1 in the pen axis direction, which is the central portion (center portion) of the joint 10 constituted by these components.
By configuring the joint 10 with a plurality of parts (at least two or more) in this way, for example, the specific gravity of the check ball 7 can be changed according to the type of ink. Alternatively, special inks such as pastel colors can be used.

Further, among the parts constituting the joint 10, at least the joint body 3, the oxygen permeability at 23 ° C. ^{is, 200 (cm 3 / m 2} / 24hr, 25μm) are formed by the following materials. When the oxygen permeability is greater than ^{200 (cm 3 / m 2 /} 24hr, 25μm), easily the gas from the outside penetrates through the joint, bubbles in the ink tends to grow. That is, when the material conditions are satisfied, it is possible to suppress the external gas from entering the ink through the parts constituting the joint.
Here, oxygen ^{permeability, 200 (cm 3 / m 2} / 24hr, 25μm) and an oxygen permeation amount of thickness 25 [mu] m, 24 hours per 1 m ² is meant to be 200 cm ^3.
For example, polybutylene terephthalate (PBT), ethylene vinyl alcohol copolymer (EVOH), polyether nitrile (PEN), polyacrylonitrile (PAN) or the like is used as the material condition.

The receiving protrusions 4 in the joint body 3 are a plurality of protrusions formed on the inner peripheral surface of the joint body 3 at equal intervals on the circumference toward the ink flow path I. The check ball 7 is supported by a horizontal plane so as not to fall downward, and only the ink 9 flows downward.
Further, an inclined surface 4a is formed on the surface of the receiving projection 3a on the ball pen tip 1 side so as to incline from the ball pen tip side toward the ink storage tube toward the center portion (center portion). In the bubble treatment, the gas (air) in the joint 10 and the ballpoint pen tip 1 easily escapes behind the pen.
Further, the seal piece 6 is formed penetrating in the pen axis direction to form an ink flow path I, and a tapered seal surface 6a inclined toward the upper side and the center of the pen is formed at the tip (ball pen tip 1 side). Is formed. Even in the inclined sealing surface 6a, the gas (air) in the joint 10 and the ball-point pen tip 1 can easily escape to the back of the pen in the centrifugal defoaming process.
The check ball 7 is loosely fitted in a space (valve space) S1 formed by the receiving projection 4 and the seal surface 6a.

As described above, at the time of normal writing, the check ball 7 is positioned on the receiving projection 4 and the ink 9 in the ink containing tube 8 communicates with the tip of the ballpoint pen tip 1.
On the other hand, for example, when the ballpoint pen 20 is turned upside down, the check ball 7 comes into close contact with the seal surface 6a, thereby closing the flow path I of the ink 9 and preventing the ink 9 from flowing back. ing.

In addition, in a state where the seal piece 6 is press-fitted and fitted into the joint body 3, a small gap G1 is formed between the joint body 3 and the seal piece 6 as shown in FIG. Yes.
In the state where the joint 10 is fitted to the ink containing tube 8, all the peripheral tip 6 c of the flange portion 6 b of the seal piece 6 is in pressure contact with the inner wall surface of the ink containing tube 8 as shown in FIG. 2. . In other words, in a state where the ballpoint pen tip 1 and the ink storage tube 8 are connected by the joint 10, the opening surface of the gap G 1 does not face the ink surface of the ink storage tube 8.

Further, a collar portion 3b formed on the joint body 3 and in contact with the end portion 8a of the ink containing tube 8 is provided with a meat stealing portion 3b so as not to be formed thicker than other portions. Thereby, the generation | occurrence | production of a sink by the heat shrink deformation | transformation produced at the time of shaping | molding of the coupling main body 3 is suppressed.
Further, in order to maintain the mechanical strength of the collar portion 3a by providing the meat stealing portion 3b, a plurality of ribs 3c are formed radially inside the meat stealing portion 3b. By providing the rib 3c, when the joint 10 is press-fitted into the ink storage tube 8 and fitted, the flange 3a is deformed by the pressing force applied from the end 8a of the ink storage tube 8 to the flange 3a. Has been made to prevent. Further, the width of the rib 3c is formed so as not to be thick. This prevents the occurrence of sink marks due to heat shrink deformation as described above.

  At the time of assembling the ballpoint pen 20 configured as described above, the check ball 7 is first inserted into the joint body 3 and the seal piece 6 is press-fitted and fitted. At this time, because of the high-speed assembly work, the gas (air) existing between the joint body 3 and the seal piece 6 becomes the gas passage in the gap G1, and escapes from the gap G1 to the outside. The gas (air) present in the valve space S1 escapes from the ink flow path I without being compressed. After the joint 10 is assembled in this way, the ball-point pen tip 1 is fitted into the joint 10.

Further, the joint 10 connected to the ballpoint pen tip 1 is fitted into the ink containing tube 8. At this time, all the peripheral edge tip portion 6c of the collar portion 6b of the seal piece 6 is in pressure contact with the inner wall surface of the ink containing tube 8 as shown in FIG. 2, so that the gas (air) in the gap G1 is completely sealed. Put into a state. Further, the ink 9 flows into the ball-point pen tip 1, and further, the operation of replacing the gas in the ball-point pen tip 1 and the joint 10 with the ink 9 is performed by centrifugal defoaming treatment.
Here, the gas in the gap G1 is not defoamed, but since the gas (air) in the gap G1 is in a sealed state, it does not leak into the ink 9 semi-permanently after product assembly.
In addition, by providing the meat stealing portion 3b on the flange portion 3a formed on the joint body 3, the occurrence of sink marks during the molding is prevented. As a result, residual gas caused by the sink portion can be suppressed, and all can be replaced with the ink 9 in the centrifugal defoaming process.

According to the embodiment of the present invention described above, the gap G1 is formed in the joint 10 so that the gas (air) between the joint body 3 and the seal piece 6 is not compressed in the joint assembly process. I can escape.
Further, in a state where the ballpoint pen tip 1 and the ink storage tube 8 are connected by the joint 10, the gap G1 does not face the ink surface of the ink storage tube 8, so that the gas (air) in the gap G1 is not present. There is no leakage into the ink when writing. For this reason, the deterioration of the quality of the ball-point pen resulting from residual gas can be prevented.

Moreover, since the inclined surface is formed in the ball-point pen tip 1 side and the seal surface 6a of the receiving protrusion 4 which is a protrusion in the joint 10, the gas in the joint is moved to the ink containing tube side in the centrifugal defoaming process. The escape can be facilitated, and the residual gas in the joint 10 and the ball tip 1 can be eliminated.
Furthermore, since the meat stealing part 3b is provided in the collar part 3a of the joint 10, the thermal contraction at the time of shaping | molding can be suppressed, and generation | occurrence | production of a sink part can be prevented. Therefore, since no gas (air) remains in the sink part, the gas can be discharged and replaced with the ink 9 more reliably in the centrifugal defoaming process.

DESCRIPTION OF SYMBOLS 1 Ball-point pen tip 2 Writing ball 3 Joint main body 3a Eaves part 3b Meat stealing part 3c Rib 4 Receiving protrusion 6 Sealing piece 6a Seal surface 6b Eaves part 6c Periphery front-end | tip part 7 Check ball 8 Ink receiving tube 9 Ink 20 Ball-point pen G1 Gap I Ink flow Road

Claims (4)

A ballpoint pen comprising a ballpoint pen tip having a writing ball that is a writing section, an ink storage tube that contains ink therein, and a joint that connects the ballpoint pen tip and the ink storage tube,
The joint has a collar portion that contacts an end portion of the ink containing tube,
A ballpoint pen characterized in that a meat stealer is formed on the collar. 2. The ballpoint pen according to claim 1, wherein the joint closes the ink flow path with the tip of the ballpoint pen tip facing upward. 3. In the component constituting the joint, the ball pen tip side surface of the protrusion protruding toward the ink flow path is formed with an inclined surface that is inclined from the ball pen tip side toward the ink storage tube toward the center portion. The ball-point pen according to claim 1, wherein the ball-point pen is provided. Part constituting the joint, the oxygen permeability at 23 ° C. ^{is, 200 (cm 3 / m 2} / 24hr, 25μm) any of claims 1 to 3, characterized in that it is formed by the following materials The ballpoint pen described in

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