JP3037168U - Ballpoint pen with ink backflow prevention mechanism - Google Patents

Abstract

(57) [Summary] [Purpose] An ink backflow prevention mechanism that enables writing without blurring by reliably preventing ink backflow caused by upward writing or impact without applying new processing to the chip itself. It is to provide a ball-point pen equipped with. [Technical Means] A ball receiving convex portion 4 is provided in an ink flow path 3-1 of a chip holder 3 for joining a chip 2 to a tip portion of an ink containing tube 1, and the ink containing tube 1 is provided behind the ball receiving convex portion 4. A valve member 6 having a communicating ink introducing port 5 is fitted to form a valve chamber 8 between the valve member 6 and the ball receiving convex portion 4, and the ink introducing port 5 is closed in the valve chamber 8. The ball valve 7 to be valved cannot be pulled out and can be inserted freely so as to improve productivity and reduce cost, and the ball valve 7 has a large ball diameter (mm) and has its own weight when writing upwards. That is, the ink introduction port 5 is closed to improve the ink backflow prevention effect.

Description

[Detailed description of the invention]

[0001]

[Industrial applications]

 The present invention relates to a ballpoint pen having an ink backflow prevention mechanism, and more particularly to a ballpoint pen having an ink backflow prevention mechanism for preventing ink backflow caused by upward writing with a tip facing upward, or impact.

[0002]

[Prior art]

 Generally, in a ballpoint pen, when the tip is facing downward, the ink in the ink storage tube flows into the tip side of the tip due to its own weight and the physical characteristics of the ink, and is rotatably held inside the tip of the tip. It is designed to be supplied to the transfer ball that is held. The ink supplied to the transfer ball is ejected by the smooth rotation of the transfer ball from the gap between the inward tip edge of the chip and the transfer ball due to the pressing (writing pressure) of the transfer ball against the writing paper. It is designed to be transferred to writing paper.

Therefore, when the chip is written upward, or when the chip is subjected to a shock or the like, air is introduced into the chip through the gap between the inward tip edge of the chip and the transfer ball. The ink in the chip returns to the ink containing tube side by its own weight, and the ink flows back. This backflow phenomenon occurs from the front side to the rear side not only in the chip but also in the ink containing tube. When the ink flows backward, the air that has entered the chip through the gap between the inward tip edge of the chip and the transfer ball forms an air pool (air layer) inside the chip and the ink containing tube. The ink remains in the inside of the cartridge, and this air pool hinders the ink supply from the ink storage tube to the chip and causes writing blurring, or the supply is completely separated and closed and no ink is supplied to the chip. Invite. In addition, the ink that has flowed back leaks into the pen shaft that is loaded with the ink containing tube, and the ink that leaks into the pen shaft flows out through the outside air introduction hole that is provided at an appropriate position of the pen shaft. Leakage caused problems such as soiling hands and clothes, and its improvement was desired.

Therefore, there has been proposed a ballpoint pen having various ink backflow prevention mechanisms developed to prevent such ink backflow and ink leakage accompanying the backflow. For example, as illustrated in FIG. 5, a valve chamber 22 is formed in a chip 21 made of a metal material that is attached to the front end of the ink containing tube 20 by bonding, and the ball valve 23 cannot be pulled out from the valve chamber 22. A ballpoint pen with an ink backflow prevention mechanism developed to prevent backflow of ink caused by upward writing, impact, etc., has been proposed (see Japanese Utility Model Publication No. 47-5661, hereafter). "). Although not illustrated, a ball body is formed in the tip by inserting a piece made of a separate member into the tip to form a valve chamber in the tip. A ballpoint pen with an ink backflow prevention mechanism in which the valve cannot be removed and is freely inserted is also proposed (see Japanese Utility Model Publication No. 53-12 4738 and Japanese Utility Model Publication No. 7-12283, hereafter “the latter”). ").

[0005]

[Problems to be solved by the device]

 However, in the former case, the hole diameter (mm) is extremely narrow, and precise cutting such as holding the transfer ball made of a metal material inside the tip with high lubrication rotatably, and assembling Even if the ball valve 23 sits in front of the valve seat 25, the valve seat 25 has an ink inlet port 24 that is closed by the ball valve 23 riding on its own weight when writing upwards. A ball receiving convex portion 28 that radially and circumferentially secures and forms an ink groove 27 that guides ink from the inside of the ink containing tube to the transfer ball 26 at the tip is formed by cutting or the like, and the ball receiving convex portion 28 and the valve are formed. Since the valve chamber 22 in which the ball valve 23 cannot be pulled out and can be freely inserted is formed between the seat 25 and the seat 25, the inside of the chip with a very narrow hole diameter becomes more complicated, and Precise processing and assembly will be required.

[0006] Therefore, in the former case, special cutting equipment is required to perform precise cutting processing inside the chip having a very small hole diameter, or a ball valve is incorporated, resulting in a rise in production cost due to equipment investment. Have problems such as. Moreover, since the tip hole diameter is small, the ball diameter (mm) of the ball valve loaded into the valve chamber inside the chip is also small, so that when writing upwards, impact, etc., the ball seats on the valve seat by its own weight. In order to close the ink inlet of the valve seat, the ink inlet cannot be reliably closed in the valve closing structure. In other words, as the ball diameter is smaller according to the hole diameter of the tip, the weight of the ball valve itself becomes lighter, so that the valve seat is ridden by its own weight and the ink inlet of the valve seat is closed. However, there is still a problem that it is not possible to prevent the backflow of ink due to upward writing and impact.

On the other hand, in the case of the latter, a chip body having an ink inlet opening that is narrower than the hole diameter is fitted into the chip, and the chip and the transfer ball are filled with ink. Between the leading diagonal front hole and the front part of the chip where the ink groove is provided, the ball valve that rides on the piece body by its own weight when writing upward and closes the ink inlet of the piece is idle. Since the valve chamber that can be freely inserted must be configured, its processing and assembly become more complicated than the above-mentioned former, and it is difficult to manufacture. Also, as in the former case, the weight of the ball valve itself becomes smaller according to the hole diameter of the tip, so the ink introduction hole of the piece body that is closed by the weight of the ball valve during upward writing must be closed reliably. Problems such as the inability to reliably prevent the backflow of ink as described above easily occur.

The present invention has been made in view of such conventional circumstances, and ink generated by upward writing, impact, etc. without performing any new machining such as complicated and troublesome cutting on the tip itself. It is an object of the present invention to provide a ballpoint pen having an ink backflow prevention mechanism that reliably prevents backflow of ink and enables writing without blurring.

[0009]

[Means for achieving the object]

 In order to achieve the above-mentioned object, the technical means taken by the present invention is to provide a ball receiving convex portion at an appropriate position in the circumferential direction in the ink flow path of the chip holder for joining the tip to the tip of the ink containing tube, and to the rear of the ink A valve member having an ink introduction port communicating with the containing tube is fitted to form a valve chamber between the valve member and the ball receiving convex portion, and the valve chamber is directed upward with the tip facing upward. It means that the ball valve that closes the ink inlet of the valve member when it is written or impacted is movably inserted without being able to be withdrawn. Here, the tip holder is an integrally molded product, and the ball valve cannot be pulled out into the valve chamber at a proper position in the circumferential direction of the inner surface of the ink flow path that communicates with the ink storage tube in the downward writing state with the tip facing down. In addition, the ball receiving convex portion that forms the ink groove that radially guides the ink that has flowed (flowed) from the ink storage tube to the valve chamber in the same writing state in the circumferential direction is formed. Provide with integral molding. The valve member communicates with the ink containing tube in the center in the downward writing state to allow the ink to flow from the ink containing tube into the valve chamber, and inside the tip in the upward writing state with the tip facing upward. A ring-shaped piece having an ink inlet that is closed by a ball valve to prevent the ink from flowing back to the ink containing tube side. By being incorporated inside the fixing device, a valve chamber is formed at an appropriate position in the axial direction of the ink flow path so that the ball valve cannot be pulled out and is freely inserted between the ball receiving convex part and the ball receiving convex part. According to such a technical means, the ink of the chip holder that joins the known structure, that is, the chip that rotatably holds the transfer ball inside the tip thereof to the tip of the ink containing tube is not processed. A ball valve installed in the valve chamber installed in the flow path rides on the valve member and closes the ink inlet of the valve member to prevent backflow of ink caused by upward writing or impact. .

[0010]

[Embodiment of the invention]

 Specific embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows an example of a core (also referred to as a replacement core) loaded in a pen shaft (not shown) of a ballpoint pen, in which a tip 2 made of a metallic material is attached to a tip holder of an ink containing tube 1 made of a known material. It is made to join by press-fitting through 3. Then, on the inner surface of the ink flow path 3-1 that connects the chip 2 of the chip holder 3 and the ink containing tube 1, there are provided ball receiving convex portions 4 projecting at appropriate intervals in the circumferential direction. A valve member 6 having an ink introduction port 5 communicating with the ink containing tube 1 is fitted in the ink flow path 3-1 at the rear of the convex portion 4, and the valve member 6 and the ball receiver Between the convex portion 4 and the tip 2, the ball chamber 7 for closing the ink inlet 5 of the valve member 6 at the time of writing upward with the tip 2 facing upward, and the valve chamber 8 into which the ball valve 7 can be inserted freely and cannot be removed. The ball valve 7 rides on the valve member 6 by its own weight when writing upward, and the ink inlet 5 of the valve member 6 is closed to return the ink in the chip 2 to the ink containing tube 1 side. To prevent.

The chip holder 3 is an integrally molded product made of a thermoplastic resin material or the like, which is molded by injection molding or another molding method, and has a joining portion 3-for joining the tip 2 to the tip thereof by press fitting or the like. 2 is provided, and the inner total length reaching the rear end opening through the small ink introduction hole 3-3 that is approximately the same as the hole diameter (pipe inner diameter) of the chip 2 with this joint 3-2. An ink flow path 3-1 that connects the chip 2 and the ink storage tube 1 is provided, and the ink in the ink storage tube 1 flows into (flows from) the ink flow path 3-1 into the chip 2. It will be like this. A ball receiving convex portion 4 is formed on the inner surface of the base end of the ink channel 3-1 which is continuous with the ink introducing hole 3-3, and which secures and forms the ink grooves 9 radially in the circumferential direction. A valve member 6 having an ink introduction port 5 communicating with the ink containing tube 1 is fitted behind the ink container 4 to form a valve chamber 8.

The ball receiving convex portion 4 allows the ball valve 7 to move freely (movably) in the axial direction in a proper range by the valve member 6, and the valve chamber 8 in which the ball valve 7 is inserted and cannot be pulled out of the tip holder 3 is provided. An ink groove 9 is provided in the ink flow path 3-1 and guides the ink from the valve chamber 8 to the ink introduction hole 3-3 communicating with the chip 2 in a radial direction on the inner surface of the ink flow path 3-1. In the inner end surface of the base end of the ink flow channel 3-1 in the continuous base end, in an appropriate position in the circumferential direction (in the figure, at three positions with a constant interval in the circumferential direction). The protrusions are integrally formed so that the ink grooves 9 are formed between the protrusions in the circumferential direction, and the ball valve 7 is received during downward writing, and the ink is passed from the valve chamber 8 to the tip through the ink groove 9. So that the ink can be continuously flown into 2 through the ink introduction hole 3-3. And comprising (state of FIGS. 1 and 2).

The valve member 6 is an integrally molded product made of a thermoplastic resin material or the like like the chip holder 3, and has a ring shape having an ink introduction port 5 having a diameter smaller than the inner diameter of the ink flow path 3-1 in the center. It is a piece and is fixedly incorporated into the ink flow path 3-1 from the rear end opening of the chip holder 3 by press fitting or the like to secure and form the valve chamber 8 between each of the ball receiving convex portions 4 described above. Is. The edge shape of the ink introduction port 5 of the valve member 6 located on the valve chamber 8 side has a taper shape that is gradually inclined toward the axial direction, and the taper portion 6 is provided at the time of upward writing or impact. The ball valve 7 rides on the -1 by its own weight so that the ink inlet 5 is closed securely. That is, the ink inlet port 5 is formed at the bottom of the taper portion 6-1 of the valve member 6 on which the ball valve 7 is mounted, with a hole diameter that is closed by the ball valve 7, and in the downward writing state, the valve chamber 8 and the ink containing tube. While the ink in the ink containing tube 1 is continuously introduced into the valve chamber 8 by communicating with the valve 1, the taper portion of the valve member 6 due to its own weight during upward writing and impact. 6-1 To prevent the backflow of the ink in the ink flow path 3-1, which does not return to the ink containing tube 1 side, because the ink inlet port 5 is reliably closed by the ball valve 7 that rides in a state of being closely contacted with it. Has become.

By the way, the hole diameter (mm) of the chip 2 in this embodiment is φ0.15, and the ball diameter (mm) of the transfer ball 10 rotatably held inside the tip of the chip 2 is more than φ0.3. For fine print. In the figure, 11 is an ink guide groove provided on the inner surface in the axial direction from the seat 12 of the transfer ball 10. The ink that has flowed into the chip 2 is guided to the transfer ball 10 by this ink guide groove 11. (See the enlarged view of FIG. 1).

According to the ink backflow prevention mechanism of the present embodiment configured as described above, the ball valve 7, which cannot be pulled out and is movably included in the valve chamber 8 provided in the chip holder 3, is as shown in FIG. In the state of writing upward, the user rides on the taper portion 6-1 of the valve member 6 by its own weight, and closes the ink inlet 5 opening at the bottom of the taper portion 6-1 to close the valve chamber 8 inside. The backflow of ink to the ink containing tube 1 side is prevented. When the writing state is downward as shown in FIG. 1, the ball valve 7 is detached from the taper portion 6-1 of the valve member 6 by its own weight and the ink inlet port 5 is opened. When the ink inlet port 5 is opened, the ink in the ink containing tube 1 passes through the ink flow path 3-1 by its own weight and once flows into the valve chamber 8 from the ink inlet port 5, and from this valve chamber 8 the ball valve is opened. 7 is continuously supplied to the chip 2 through the ink groove 9 between the ball receiving convex portions 4 being received, and is supplied to the transfer ball 10 at the tip of the chip 2.

In this embodiment, the valve chamber 8 is provided in the ink flow path 3-1 of the chip holder 3 and the ball valve 7 is installed to prevent ink from flowing backward due to upward writing or impact. Since it is built-in, the ball diameter (mm) of the ball valve 7 can be made considerably larger and the weight of the ball valve 7 can be made heavier than before. That is, compared to the conventional ink backflow prevention structure in which a valve chamber is formed in a chip with a very small hole diameter (mm) and a ball valve is installed internally, an ink flow with a significantly larger hole diameter (mm) is used. A ball receiving convex portion 4 and a valve member 6 are provided in the passage 3-1 to form a valve chamber 8 in which a ball valve 7 for preventing backflow of ink caused by upward writing or impact is installed. Therefore, the ball diameter of the ball valve 7 can be increased according to the hole diameter of the ink flow path 3-1. Therefore, the ball valve 7 with its own weight rides in close contact with the taper portion 6-1 of the valve member 6, and surely closes the ink inlet port 5 opening from the bottom of the taper portion 6-1 so that it is directed upward. It is possible to reliably prevent the backflow of ink even when the writing state or a shock is received.

Therefore, according to the ink backflow prevention mechanism of the present embodiment, the ball valve 7 charged in the valve chamber 8 is securely closed while the ink inlet port 5 of the valve member 6 is brought into close contact with itself by its own weight. Since the valve is used, it is possible to surely prevent the backflow of the ink caused by the upward writing and the impact. Further, the ball receiving convex portion 4 is integrally provided in the ink flow path 3-1 having a large hole diameter of the chip holder 3 and the valve member 6 is provided by fitting so that the ball valve 7 cannot be removed and is freely inserted. Since the valve chamber 8 for preventing backflow of ink is provided as a component, the manufacturing thereof is simple and inexpensive, and the ballpoint pen having the ink backflow prevention mechanism can be provided at a lower cost than the conventional one.

FIG. 4 shows another embodiment in which the projecting position and the fitting position of the ball receiving convex portion 4 and the valve member 6 in the ink flow path 3-1 of the chip holder 3 are changed. In other words, the valve chamber 8 into which the ball valve 7 cannot be removed and is freely inserted is provided in the inner surface portion of the rear end opening of the tip holder 3 to prevent backflow of ink caused by upward writing and impact. It was done like this. As described above, in this embodiment, the same components as those in the above-described embodiment are basically the same as those in the above-mentioned embodiment in the configuration except that the projecting position and the fitting position of the ball receiving convex portion 4 and the valve member 6 are changed. By using the same reference numerals for the above, detailed description and operation thereof will be omitted.

[0019]

[Effect of the invention]

 Since the core of the present invention for ball-point pens is constructed as described above, it has the following operational effects. . The tip holder that joins the tip to the tip of the ink storage tube is equipped with an ink backflow prevention mechanism that prevents backflow of ink when writing upwards. By joining the tip to the tip of the ink containing tube via the tip holder, a ballpoint pen having an ink backflow prevention mechanism can be manufactured. . A ball valve is installed inside the ink path of the tip holder, and a ball valve that prevents backflow of the ink during upward writing is installed internally. Can be considerably large, and the ball weight can be increased to increase the own weight. In other words, compared with the conventional ink backflow prevention structure in which a valve chamber is formed in a chip with a very small hole diameter (mm) and a ball valve is installed internally, the ink flow path with a significantly larger hole diameter (mm) is used. A ball valve having a ball diameter corresponding to the hole diameter and having its own weight is inserted in the valve chamber, and the backflow of ink can be prevented by the ball valve. In other words, a heavy ball valve with a ball diameter that matches the hole diameter of the ink flow path rides on the valve member in close contact, and the ink inlet of the valve member is reliably closed, thus preventing backflow of the ink. It can be expected to improve the effect.

Therefore, according to the present invention, not only does the structure become complicated as in the conventional case, but also the chip itself, which requires complicated and highly accurate processing, can be easily manufactured without any new processing. Therefore, it is expected that the production cost will be greatly reduced and the productivity will be improved. Therefore, it is possible to provide a ballpoint pen having an ink backflow prevention mechanism that improves productivity, reduces cost, and further improves the ink backflow prevention effect.

[Brief description of the drawings]

FIG. 1 is a vertical cross-sectional view showing a core of a ballpoint pen having an ink backflow prevention mechanism according to the present invention, showing a writing state facing downward.

2 is an enlarged cross-sectional view taken along the line II-II in FIG.

FIG. 3 is a vertical sectional view showing an upward writing state.

FIG. 4 is a vertical sectional view showing another embodiment.

FIG. 5 is a vertical sectional view showing a conventional example.

[Explanation of symbols]

 1 ... Ink Storage Tube 2 ... Chip 3 ... Chip Holder 3-1 ... Ink Flow Path 4 ... Ball Receiving Convex 5 ... Ink Inlet 6 ... Valve Member 7 ... Ball Valve 8 ... Valve Chamber 9 ... Ink Groove 10 ... Transfer Ball

Claims (1)

[Utility model registration claims] 1. A ball receiving convex portion is provided in an ink flow path of a chip holder for joining a chip to a tip portion of an ink containing tube,
A valve member having an ink introduction port communicating with the ink containing tube is fitted behind the ball receiving convex portion to form a valve chamber between the valve member and the ball receiving convex portion. A ballpoint pen equipped with an ink backflow prevention mechanism, characterized in that a ball valve that closes the ink inlet port cannot be pulled out and is inserted freely.