JP7041486B2 - Stationery - Google Patents

Description

The present invention relates to a writing tool, and more particularly to a writing tool that suppresses the writing portion from falling off from the front axis.

Conventionally, as shown in Patent Document 1, a writing tool having a pen core at the tip end portion (front shaft) of a shaft cylinder and air-replacement of an ink accommodating portion in the shaft cylinder has been proposed.
The writing tool shown in Patent Document 1 will be described. A pen core is attached to the opening at the tip of the shaft cylinder, and the pen core is held by a tip shaft having an air groove. Specifically, a plurality of ribs are extended in the axial direction on the inner peripheral surface of the front shaft, the pen core is held by the plurality of ribs, and an air groove is formed between the ribs.

Further, an ink storage body made of a fiber bundle is housed in the shaft cylinder, and the rear end of the pen core is immersively connected to the tip of the ink storage body.
In this way, the pen core is held by the tip shaft, and an air groove is arranged on the outer periphery of the pen core by the rib, and the inside of the shaft cylinder communicates with the outside air by the air groove.

Japanese Unexamined Patent Publication No. 9-86091

By the way, in the writing tool shown in Patent Document 1, a plurality of ribs are formed on the inner peripheral surface of the leading shaft, and the pen core (writing portion) is held by the ribs.
Therefore, there is a problem that the inner diameter of the entire rib tip that holds the writing part must be manufactured with high dimensional accuracy, and the outer diameter of the writing part must also be manufactured with high dimensional accuracy. rice field.
That is, when the inner diameter of the rib tip and the outer diameter of the writing portion are not formed with high dimensional accuracy, the writing portion does not fit to the front shaft or the writing portion is not securely held by the front shaft. In, there was a problem that the writing part was inadvertently dropped from the front axis.

The present invention has been made to solve the above technical problems, and it is possible to set a predetermined allowable range for the inner diameter of the holding portion for holding the writing portion and the outer diameter of the writing portion, and it is possible to set a predetermined allowable range for writing. It is an object of the present invention to provide a writing tool in which a portion is securely held on a front shaft.

The writing tool according to the present invention, which has been made to achieve the above object, is a writing tool in which ink is stored in a barrel and a tip shaft holding a writing portion is screwed to the tip of the barrel. On the inner peripheral surface of the front shaft, a holding portion for holding the writing portion, which is composed of a plurality of ribs formed from the inner peripheral surface in the center direction of the front shaft and in the axial direction of the front shaft, is provided. The holding portion holds the writing portion by pressure-contacting with the outer periphery of the writing portion, gives sliding resistance to the advancing and retreating of the writing portion, and from the sliding contact portion and the inner diameter of the sliding contact portion. It also has a guide portion formed with a large inner diameter to guide the writing portion when the writing portion advances and retreats , and further, a female screw portion formed on the inner peripheral surface of the front shaft and screwed to the female screw. A male thread portion formed on the outer peripheral surface of the shaft cylinder is provided, and the width of the thread of the female thread portion is the width of the thread on the front end side of the front shaft rather than the width of the thread on the rear end side of the front shaft. The width of the thread of the male thread is larger than the width of the thread on the rear end side of the barrel, corresponding to the width of the thread on the female thread. The inner diameter of the female threaded portion gradually decreases from the rear end side of the front end toward the tip end side, and the outer diameter of the male threaded portion corresponds to the inner diameter of the female threaded portion. It is characterized by gradually becoming smaller from the side to the tip side .

As described above, in the writing instrument according to the present invention, since the writing portion and the sliding contact portion are in pressure contact with each other, the writing portion is securely held by the front shaft, and the writing portion is inadvertently dropped from the front shaft. Can be prevented.
Further, since the writing portion and the sliding contact portion are in pressure contact with each other, an appropriate sliding resistance can be given when the writing portion moves forward and backward in the front axis.

Further, a guide portion is provided at a position formed with an inner diameter larger than the inner diameter of the sliding contact portion, that is, at a position lower than the height of the sliding contact portion, to guide the writing portion when the writing portion advances or retreats. With this guide unit, it is possible to prevent the writing unit from tilting when the writing unit moves forward and backward, and it is possible to obtain a smooth moving movement of the writing unit.

Here, since the guide portion is formed with an inner diameter larger than the inner diameter of the sliding contact portion, the writing portion may have an outer diameter within a range that is in contact with the sliding contact portion and not in contact with the guide portion.
When the writing portion is in pressure contact with both the sliding contact portion and the guide portion, the writing portion is reliably held, but the sliding resistance becomes large, and the writing portion cannot smoothly move forward and backward.
Therefore, there is an inner diameter difference (for the height of the sliding contact portion) between the sliding contact portion and the guide portion as an allowable range of the dimensions of the inner diameter of the holding portion that holds the writing portion and the outer diameter of the writing portion.
As a result, the writing part is securely held by the front shaft without using the holding part and the writing part manufactured with high dimensional accuracy, and it is possible to prevent the writing part from being inadvertently dropped from the front shaft. Further, when the writing unit moves forward and backward in the front shaft, an appropriate sliding resistance can be given.

Here, it is desirable that the rib has the sliding contact portion and the guide portion, the sliding contact portion is formed on the tip end side of the tip shaft, and then the guide portion is formed.
Further, it is desirable that the sliding contact portion and the guide portion are formed on separate ribs.

Further, the writing tool according to the present invention is a writing tool that is attached to the tip of the shaft cylinder by screwing a front shaft that holds the writing portion, and is a female screw portion formed on the inner peripheral surface of the front shaft. And a male thread portion formed on the outer peripheral surface of the shaft cylinder to be screwed into the female thread, and the width of the thread of the female thread portion is larger than the width of the thread on the rear end side of the front shaft. The width of the thread on the side is smaller, and the width of the thread of the male thread corresponds to the width of the thread of the female thread, which is larger than the width of the thread on the rear end side of the barrel. The width of the thread on the tip side of the cylinder is smaller .
With such a configuration, the relative position between the front shaft and the shaft cylinder does not become slanted, it is possible to prevent inadvertent overshooting of the shaft cylinder, and it is possible to stabilize the screwing of the front shaft and the shaft cylinder. ..

Further, the writing tool according to the present invention includes a female threaded portion formed on the inner peripheral surface of the rear end portion of the front shaft and a male threaded portion formed on the inner peripheral surface of the tip end portion of the shaft cylinder screwed to the female threaded portion. , The inner diameter of the female screw portion gradually decreases from the rear end side of the front shaft toward the tip side, and the outer diameter of the male screw portion corresponds to the inner diameter of the female screw portion at the rear end of the shaft cylinder. It is configured to gradually decrease from the side to the tip side.
In this way, the inner diameter of the female threaded portion is formed smaller as it goes toward the tip end side of the front shaft (the outer diameter of the male threaded portion is formed smaller as it goes from the rear end side to the tip end side of the barrel). Therefore, it is possible to further stabilize the screwing of the toe shaft into the barrel.

Further, in the female screw portion formed on the inner peripheral surface of the rear end portion of the front shaft, the female screw end portion on the rear end portion side of the front shaft gradually rises from the inner peripheral surface of the front shaft to form a thread. Is desirable.
In this way, since the end of the female screw gradually rises from the inner peripheral surface of the front shaft to form a thread, it is possible to more easily screw the front shaft into the cylinder.
Further, it is desirable that a parting line is formed at the rear end of the sliding contact portion, and it is desirable that the sliding force (holding force) of the writing portion with respect to the front shaft is 0.1 to 2.0 N.
Further, the ink contains at least carbon black or an organic pigment, a dispersant, a lower alcohol, a fixing resin, and a polyether-modified silicone having a polyoxyalkylene portion, and the polyoxyalkylene of the polyether-modified silicone. Contains an ink composition for an oil-based marking pen, which is composed only of polyoxyethylene, has an average degree of polymerization in the range of 20 to 50, and has a melting point of 40 ° C. or higher for the polyether-modified silicone. Is desirable.

According to the present invention, it is possible to set a predetermined allowable range for the dimensions of the inner diameter of the holding portion for holding the writing portion and the outer diameter of the writing portion, and to obtain a writing tool in which the writing portion is reliably held on the front axis. be able to.

FIG. 1 is a perspective view showing a first embodiment of the writing tool according to the present invention. FIG. 2 is a cross-sectional view of the writing tool shown in FIG. FIG. 3 is a perspective view of the front axis shown in FIG. 4 (a) is a cross-sectional view of the front axis shown in FIG. 3, and FIG. 4 (b) is an enlarged view of an X portion of (a). 5A and 5B are views showing a state in which a writing tool is attached to a front shaft, where FIG. 5A is a side view and FIG. 5B is a cross-sectional view. FIG. 6 is a front view of the front axis shown in FIG. FIG. 7 is a partially enlarged view of the front axis shown in FIG. FIG. 8 is a diagram for explaining the dimensional allowable range of the outer diameter of the writing portion and the inner diameter of the sliding contact portion. FIG. 9 is a cross-sectional view illustrating a mold for manufacturing a toe shaft. 10A and 10B are views for explaining a second embodiment, where FIG. 10A is a front view, FIG. 10B is a sectional view taken along the line II of FIG. II is a cross-sectional view. 11A and 11B are perspective views of the front axis shown in FIG. 10, where FIG. 11A is a perspective view seen from the front and FIG. 11B is a perspective view seen from the rear.

Hereinafter, the first embodiment of the writing tool according to the present invention will be described with reference to FIGS. 1 to 10.
As shown in FIGS. 1 and 2, the writing instrument 1 includes a shaft cylinder 2 for accommodating ink, a valve mechanism 4 mounted in the tip portion 2a of the shaft cylinder 2, and an outer periphery of the tip portion 2a of the shaft cylinder 2. It is equipped with a tip shaft 6 that guides the writing section (pen core) 5 when the writing section 5 moves forward and backward, and a cap 3 that covers the writing section 5 and is fitted to the tip shaft 6. ing.

Subsequently, each member constituting this writing instrument will be described in more detail.
[Cap 3]
As shown in FIG. 1, a plurality of groove portions 3b for ventilating the outer peripheral surface of the body portion 3a of the substantially tubular body portion 3a are formed in the cap 3 in the circumferential direction. Further, a plurality of convex portions 3c extending in the axial direction are arranged in the circumferential direction on the outer periphery of the body portion 3a in which the groove portion 3b is not formed. Although the groove portion 3b and the convex portion 3c are formed in six places in FIG. 1, it is desirable to provide at least two places or more from the viewpoint of safety of ventilation when an infant or the like accidentally swallows.
Further, it is desirable that the groove portion 3b has a width of 2.0 mm or more and a depth of 0.5 mm or more in the central direction on the opening portion 3f side of the cap 3. As the material of the cap 3, it is desirable to use a resin material such as polypropylene, polycarbonate, ABS, etc., instead of a rubber elastic material having viscoelasticity typified by rubber / elastomer.

On the opening 3f side of the cap 3, the maximum width W2 in the circumferential direction of the groove 3b is smaller than the minimum width W1 in the circumferential direction of the convex portion 3c, so that the cap 3 and the shaft cylinder 2 are packaged in the entire outer periphery. Even if the material is covered, unintended damage can be prevented.
On the distal end portion 3g side of the cap 3 in FIG. 1, the maximum width W3 in the circumferential direction of the groove portion 3b is formed to be larger than the minimum width W4 in the circumferential direction of the convex portion 3c, but naturally, the circumferential direction of the convex portion 3c. It may be provided smaller than the minimum width W4 of.

As shown in FIG. 2, an inner cylinder 3d is formed on the inner peripheral surface of the front portion of the body portion 3a, and the writing portion 5 is in contact with the front side surface of the front shaft 6 on the inner surface of the inner cylinder 3d. The seal portion 3e that keeps the airtightness of is formed. Further, a fitting portion 3h that fits with the front shaft 6 is formed on the rear inner surface of the body portion 3a.

[Shaft tube 2]
As shown in FIG. 2, the tip portion 2a of the barrel 2 has a smaller outer diameter than the central portion of the barrel 2, and the tip thereof is open. Further, the rear end portion 2b of the barrel 2 is closed.
An ink accommodating portion 2c for accommodating ink is formed inside the barrel 2. That is, the barrel 2 has the function of a container for containing ink made of metal or resin for accommodating ink. Reference numeral 7 in FIG. 2 is a stirring ball for stirring the ink contained in the barrel 2.

[Valve mechanism 12]
As shown in FIG. 2, the valve mechanism 4 mounted in the tip portion 2a includes a holder 4a, a valve body 4b, a valve seat 4c, and a spring 4d.
The holder 4a is a tubular body having a flange 4a1 at the tip and an ink flow hole 4a2 formed at the rear surface. The rear portion of the valve body 4b is movably mounted in the ink flow hole 4a2.
Further, the valve body 4b has an umbrella-shaped annular protrusion 4b1 formed on the peripheral surface of the central portion thereof. The tip of the valve body 4b is provided with a hollow opening 4b2, and the rear end of the writing portion 5 is in contact with the opening 4b2 (the tip surface 4b3 of the valve body 4b).

Further, a cylindrical valve seat 4c having a length dimension shorter than that of the holder 4a is attached to the tip end portion of the holder 4a. The valve seat 12c is positioned on the holder 4a by abutting the flange portion 4c1 around the valve seat 4c on the tip end surface of the flange of the holder 4a.
The peripheral surface of the valve body 4b is configured to abut and detach from the concave seat surface 4c2 at the rear of the valve seat 4c to perform a valve function.

Further, the spring 4d is mounted between the valve body 4b and the holder 4a. The spring 4d returns the valve body 4b separated from the valve seat 4c to a state in which the valve body 4b abuts on the valve seat 4c due to the repulsive force of the spring 4d.
The holder 4a, the valve body 4b, and the valve seat 4c are made of a resin material. The spring 4d is made of an elastic member such as SUS or resin.

[Writing section 5]
As shown in FIG. 2, the writing unit 5 has a cannonball-shaped tip and rear end, and has a substantially columnar shape as a whole. The rear end surface 5a of the writing portion 5 is in contact with the tip surface 4b3 of the valve body 4b, and the writing portion 5 is configured to be able to move forward and backward with respect to the holding portion 6a formed on the inner surface of the front shaft 6. ing.
Further, the writing unit 5 may have a structure made of various materials such as an ink derivative made of resin, a fiber bundle made of resin or natural fiber, and an open cell made of resin.

Specifically, the ink is supplied and shut off to the writing unit 5 by the following operations and actions.
When the writing portion 5 is pressed against the paper surface while resisting the repulsive force of the spring 4d, the writing portion 5 moves backward with respect to the holding portion 6a and pushes the valve body 4b backward. Then, the pressed valve body 4b is separated from the valve seat 4c, the valve is opened, and the ink contained in the barrel 2 is supplied to the writing unit 5.
On the other hand, when the writing portion 5 is separated from the paper surface, the writing portion 5 and the valve body 4b move to the front due to the repulsive force of the spring 4d. Then, the valve body 4b that has moved to the front side abuts on the valve seat 4c, closes the valve, and shuts off the ink supply.

As shown in FIG. 2, a cylindrical sponge 8 is provided so as to surround the outer periphery of the rear end surface 5a of the writing portion 5 and the front end surface 4b3 of the valve body 4b. The sponge 8 absorbs excess ink supplied to the writing unit 5 and suppresses ink leakage from the writing tool 1.

[Top axis 6]
As shown in FIGS. 2 to 4, the internal shape of the toe shaft 6 is formed in a shape in which the diameter is gradually increased from the tip portion. That is, the toe shaft 6 has an inner diameter between the inner diameter D1 of the main body having the smallest inner diameter D1, the rear end portion 6C of the main body having the largest inner diameter D3, and the inner diameter D1 of the tip portion 6A of the main body and the inner diameter D3 of the rear end portion 6C of the main body. It is provided with a main body intermediate portion 6B having D2.
Corresponding to the internal shape of the front shaft 6, the outer shape of the front shaft 6 is formed into a so-called staircase shape in which the outer diameter gradually increases from the tip portion.

Further, as shown in FIGS. 2 and 5, the main body tip portion 6A has a holding portion 6a for holding the writing portion 5 so as to be slidable, and the main body intermediate portion 6B accommodates a sponge for accommodating the sponge 8. The main body rear end portion 6C has a portion 6b, and the main body rear end portion 6C has a screw portion 6c for mounting on the outer peripheral surface of the tip portion 10a of the barrel 10.

[Holding unit 6a]
Subsequently, the holding portion 6a of the main body tip portion 6A will be described.
As shown in FIGS. 4 to 7, a plurality of inner peripheral surfaces of the main body tip 6A are formed from the inner peripheral surface in the central direction of the main body tip 6A and in the axial direction of the main body tip 6A. Ribs are formed. The plurality of ribs form a holding portion 6a that holds and guides the writing portion 5.
As shown in FIG. 6, four holding portions 6a are formed on the inner peripheral surface of the main body tip portion 6A at 90-degree intervals.
Air can be introduced from the gap (gap of the rib) of the holding portion 6a, and when the valve mechanism 4 operates, air can be introduced into the barrel 2 and so-called air replacement can be performed.

Further, as shown in FIG. 7, a sliding contact portion 6a1 protruding in the central direction of the main body tip portion 6A is formed at the tip portion (tip side of the tip shaft 6) of the holding portion 6a.
Further, the holding portion 6a other than the sliding contact portion 6a1 is formed with an inner diameter larger than the inner diameter of the sliding contact portion 6a1, that is, at a position lower than the height of the sliding contact portion, when the writing portion 5 advances and retreats. Is provided with a guide unit 6a2 for guiding the writing unit 5. The guide portion 6a prevents the writing portion 5 from tilting when the writing portion 5 slides.

Next, the reason why the sliding contact portion 6a1 is provided will be described with reference to FIG.
First, when the sliding contact portion 6a1 is not provided, as shown in FIG. 8A, the inner diameter of the holding portion 6a is formed to have the same diameter, and the outer diameter of the writing portion 5 is also formed to have the same diameter. Therefore, the inner diameter of the holding portion 6a and the outer diameter of the writing portion 5 need to be the same so that they are in contact with each other.
That is, when the inner diameter of the holding portion 6a is larger than the outer diameter of the writing portion 5 (state X in FIG. 8A), the outer peripheral surface of the writing portion 5 does not contact the inner peripheral surface of the holding portion 6a. Therefore, sliding resistance cannot be obtained. In other words, the writing unit 5 has a problem that it easily falls off from the toe shaft 6. On the other hand, when the inner diameter of the holding portion 6a is smaller than the outer diameter of the writing portion 5 (the state of Y in FIG. 8A), the entire holding portion 6a is in pressure contact with the outer peripheral surface of the writing portion 5 and slides. The resistance becomes extremely large. In other words, the writing unit 5 is difficult to fall off from the front shaft 6, but there is a problem that a large force is required for the writing unit 5 to move forward and backward.

On the other hand, when the sliding contact portion 6a1 is formed in a part of the holding portion 6a, the inner diameter dimension of the sliding contact portion 6a1 is smaller than the outer diameter dimension of the writing portion 5 (FIG. 8 (b). In the state of Y), the sliding contact portion 6a1 is in pressure contact with the outer peripheral surface of the writing portion 5, but the entire holding portion 6a (guide portion 6a2) is not in pressure contact, so that the sliding resistance does not increase so much. In other words, the writing unit 5 is difficult to fall off from the front shaft 6, and the writing unit 5 does not require a large force to move forward and backward.
As a result, the inner diameter of the sliding contact portion 6a1 and the outer diameter of the writing portion 5 have an allowable range of the height dimension t of the sliding contact portion 6a1 (difference in diameter between the sliding contact portion 6a1 and the guide portion 6a2).
Therefore, it is not necessary to use the toe shaft 6 and the writing unit 5 manufactured with high dimensional accuracy.

Specifically, the length dimension and the height dimension (sliding contact portion 6a1) of the sliding contact portion 6a1 are such that the sliding force (holding force) of the writing portion 5 with respect to the toe shaft 6 is 0.1 to 2.0 N. It is desirable to design the difference in diameter between the guide portion 6a2 and the guide portion 6a2). It is desirable that the inner diameter of the sliding contact portion 6a1 is formed to be 0.01 to 0.15 mm smaller than the outer diameter of the writing portion 5 in terms of dimensional difference.

[Screw part 6c]
Next, the screw portion 6c of the rear end portion 6C of the main body will be described.
As schematically shown in FIG. 4B, the cross section of the thread 6c1 in the thread 6c has a flat top and an arcuate side surface, and the widths t1 and t2 of the thread 6c1 are the leading axes. It is formed narrower toward the tip side of 6. Further, as schematically shown in FIG. 4A, the inner diameter D4 of the threaded portion 6c is formed so as to become smaller toward the tip end side of the front shaft 6. The pitch P of the thread 6c1 is formed to be the same.
Further, although not shown, the width of the thread of the thread on the shaft tube 6 side also corresponds to the width of the thread 6c1 of the thread 6c, rather than the width of the thread on the rear end side of the shaft. The width of the thread on the tip side is smaller. Further, the outer diameter of the threaded portion on the barrel 6 side is gradually reduced from the rear end side to the tip end side of the barrel, corresponding to the inner diameter of the thread 6c1 of the screw portion 6c.

In this way, since the thread widths t1 and t2 are formed smaller toward the tip side of the front shaft 6, the relative position between the front shaft and the shaft cylinder is not slanted and the shaft cylinder is careless. It is possible to prevent the screw from getting over and stabilize the screwing.
Further, since the inner diameter D4 of the threaded portion 6c is formed smaller toward the tip end side of the front shaft 6, the screwing of the front shaft into the cylinder can be more stable.

Further, as shown in FIGS. 3 and 5, the end portion 6c2 of the screw thread 6c1 on the rear end side of the front end shaft 6 gradually rises from the inner peripheral surface of the rear end portion 6C of the main body, and a slope forming the thread 6c is formed. It is formed.
Since the end portion 6c2 of the threaded portion 6c is formed on the slope in this way, it is possible to more easily screw the leading shaft into the barrel.

The leading shaft 6 is manufactured by using the mold 20 shown in FIG. 9, the first core pin 21, the second core pin 22, and the third core pin 24.
That is, the first core pin 21 is advanced into the mold 20, and the integrated second core pin, the third core pin 24, and the stripper bush 25 are advanced to form the leading shaft 6 in the mold 20. A cavity P is formed.
Then, by injecting the molten resin from the molten resin injection port (not shown), the toe shaft 6 is molded by so-called injection molding.

After molding, the integrated second core pin, third core pin 24, and stripper bush 25 are retracted from the mold 20. At this time, since the toe shaft 6 formed is attached to the second core pin and the third core pin 24, the toe shaft 6 is carried out of the mold 20 as the second core pin, the third core pin 24, and the stripper bush 25 move. Will be done.
After that, the molded toe shaft 6 can be taken out by pulling out the second core pin from the molded toe shaft 6 and further pulling out the third core pin 24 while rotating through the stripper bush 25.

Further, the butt surface 23 between the first core pin 21 and the second core pin 22 is configured to be located at the rear end of the sliding contact portion 6a1. That is, since the outer diameter of the second core pin 22 is small, it is difficult in terms of processing to form the sliding portion 6a1 and the guide portion 6a2 having slightly different outer diameters on the second core pin 22. be.
Therefore, a portion corresponding to the sliding contact portion 6a1 is formed at the tip end portion of the first core pin 21, and a portion (guide portion 6a2) corresponding to the guide portion 6a2 is formed at the tip end portion of the second core pin 22.
When the toe shaft 6 is formed by using the first core pin 21 and the second core pin 22 as described above, a so-called parting line, which is a dividing surface, is formed at the rear end of the sliding contact portion 6a1 of the toe shaft 6. It is formed.

The rear portion of the toe shaft 6 thus formed is mounted on the outer peripheral surface of the tip end portion 2a of the barrel 2.
By mounting the tip shaft 6 on the tip portion 2a of the barrel 2, the valve mechanism 4 is fixed to the tip portion of the barrel 2. Further, the writing portion 5 is in pressure contact with the sliding contact portion 6a1 of the holding portion 6a, and is held slidably in the front-rear direction with an appropriate sliding resistance. Further, when the writing unit 5 slides, the writing unit 5 is guided by the guide unit 6a2, so that the writing unit 5 slides without tilting.

[Ink composition]
As the ink used for the writing tool of the present invention, for example, an ink for an oil-based marking pen is used. The ink composition for an oil-based marking pen is not particularly limited, but is a polyether-modified silicone having at least carbon black or an organic pigment, a dispersant, a lower alcohol, a fixing resin, and a polyoxyalkylene moiety. An ink composition for an oil-based marking pen containing the above, wherein the polyoxyalkylene portion of the polyether-modified silicone is composed only of polyoxyethylene, the average degree of polymerization is in the range of 20 to 50, and the degree of polymerization is in the range of 20 to 50. Those having a melting point of 40 ° C. or higher for the polyether-modified silicone are preferably used.

In addition to the above components, this ink composition for oil-based marking pens is difficult as long as it does not impair the effects of writing on kraft tape, sticking to polypropylene, and writing after storing downward in the writing section. Various additives such as benzyl alcohol as a volatile liquid, ethyl lactate, and a pigment surface treatment agent for further improving pigment dispersibility can be appropriately selected and used.

Further, it is desirable that the viscosity (25 ° C., the same applies hereinafter) is 3 to 30 mPa · s from the viewpoint of enabling writing without blurring.
In the ink composition for an oil-based marking pen configured as described above, even in a pigment-based ink composition containing carbon black or an organic pigment, the polyether-modified silicone having the above-mentioned physical properties is contained as the polyether-modified silicone. As a result, it has better dispersion stability than conventional inks containing liquid polyether-modified silicone or trimethylsiloxysilicic acid, and it is reliable even when written on the surface of difficult-to-attach parts such as polyethylene or the surface of kraft tape. It can be written on the surface and has excellent adhesiveness.

Next, the operation and operation of the writing tool 1 according to the present invention will be described.
First, ink is stored in the shaft cylinder 2, and the valve mechanism 4 is mounted in the shaft cylinder 2. Then, the tip shaft 6 is attached to the tip end portion of the shaft cylinder 2. After that, the writing unit 5 is press-fitted into the leading shaft 6.
Since the dimensional difference between the outer diameter of the writing unit 5 and the inner diameter of the sliding contact portion 6a1 of the toe shaft 6 is allowed within a predetermined range, it is necessary to use the writing unit 5 and the toe shaft 6 with strict dimensional control. There is no.

In the writing tool 1 assembled in this way, the writing portion 5 is in contact with the tip of the valve body 12b of the valve mechanism 4. At all times, the valve body 4b is pressed forward by the spring 4d and abuts on the valve seat 4c to close the valve mechanism 4.
Then, when supplying ink to the writing unit 5, the user holds the barrel 2 and presses the writing unit 5 against a paper surface or the like to move the writing unit 5 backward. As a result, the valve body 4b is separated from the valve seat 4c, the valve mechanism 4 is opened, and ink is supplied to the writing unit 4.

When the writing portion 5 is pressed against a paper surface or the like to move the writing portion 5 backward, the sliding contact portion 6a1 is in pressure contact with the outer peripheral surface of the writing portion 5, so that an appropriate sliding resistance is received. Further, since an appropriate sliding resistance is formed between the sliding contact portion 6a1 and the outer peripheral surface of the writing portion 5, it is possible to prevent the writing portion from being unintentionally dropped by the user during use.

Next, a second embodiment of the writing tool according to the present invention will be described with reference to FIGS. 10 and 11.
In the first embodiment, the case where the sliding portion 6a1 and the guide portion 6a2 are formed on one rib (holding portion 6a) is shown.
However, the present invention is not limited to this. For example, as shown in FIGS. 10 and 11, the sliding portion 6a1 and the guide portion 6a2 may be formed on separate ribs. That is, as shown in FIG. 10A, a plurality of ribs forming the sliding portion 6a1 (shown in the case of four in the figure) and a plurality of ribs forming the guide portion 6a2 (in the case of four in the figure). Is shown).
The dimensional difference between the inner diameters of the plurality of ribs forming the sliding portion 6a1 and the inner diameters of the plurality of ribs forming the guide portion 6a2 is the difference between the outer diameter of the writing portion 5 and the inner diameter of the sliding contact portion 6a1 of the toe shaft 6. It is not necessary to use the writing unit 5 and the toe shaft 6 which have been subjected to strict dimensional control as in the first embodiment because the dimensional difference is allowed.

Further, in the first embodiment, the case where the cross section of the thread 6c1 in the thread portion 6c is formed in an arc shape is shown, but as shown in FIGS. 10 and 11, the thread 6c1 has a thread 6c1. The cross section may have a trapezoidal shape (a shape in which the top is formed on a flat surface and the side surface is formed on a flat surface).
Also in this case, the widths t1 and t2 of the thread 6c1 are formed narrower toward the tip end side of the toe shaft 6 as in the first embodiment. Further, it is desirable that the inner diameter D4 of the threaded portion 6c is formed so as to become smaller toward the tip end side of the toe shaft 6.
Further, it is desirable that the end portion 6c2 of the thread 6c1 on the rear end side of the front end gradually rises from the inner peripheral surface of the rear end portion 6C of the main body to form a slope forming the thread 6c.
By forming the screw thread 6c1 in this way, the same effect as that of the first embodiment can be obtained.

1 Writing tool 2 Shaft cylinder 3 Cap 4 Valve mechanism 5 Writing part 6 Tip shaft 6a Holding part 6a1 Sliding contact part 6a2 Guide part 6c Thread part 6c1 Thread 6c2 Thread end D4 Tip shaft Thread width t1, t2 Thread width

Claims (5)

A writing tool in which ink is stored in a shaft cylinder, and a tip shaft holding a writing portion is screwed onto the tip of the shaft cylinder.
The inner peripheral surface of the front shaft is provided with a holding portion for holding the writing portion, which is composed of a plurality of ribs formed from the inner peripheral surface toward the center of the front shaft and in the axial direction of the front shaft.
The holding portion holds the writing portion by pressure-contacting with the outer periphery of the writing portion, gives sliding resistance to the advancing and retreating of the writing portion, and is larger than the inner diameter of the sliding contact portion and the sliding contact portion. It has a guide section formed by the inner diameter to guide the writing section when the writing section moves forward and backward.
Further, a female screw portion formed on the inner peripheral surface of the front shaft and a male screw portion formed on the outer peripheral surface of the shaft cylinder screwed to the female screw are provided.
The width of the thread on the female thread portion is smaller than the width of the thread on the rear end side of the front shaft, and the width of the thread on the tip side of the front shaft corresponds to the width of the thread on the female thread portion. The width of the thread of the male thread portion is smaller than the width of the thread on the rear end side of the barrel, and the width of the thread on the tip side of the barrel is smaller.
Further, the inner diameter of the female screw portion gradually decreases from the rear end side of the front shaft toward the tip side, and the outer diameter of the male screw portion corresponds to the inner diameter of the female screw portion from the rear end side to the tip side of the barrel. A writing tool characterized by gradually becoming smaller toward . In the female threaded portion formed on the inner peripheral surface of the rear end of the front shaft, the end of the female thread on the rear end of the front shaft gradually rises from the inner peripheral surface of the front shaft to form a thread. The writing tool according to claim 1 , which is a feature. The writing tool according to claim 1 or 2, wherein a parting line is formed at the rear end of the sliding contact portion . The writing tool according to any one of claims 1 to 3, wherein the sliding force (holding force) of the writing portion with respect to the leading shaft is 0.1 to 2.0 N. The ink contains at least carbon black or an organic pigment, a dispersant, a lower alcohol, a fixing resin, and a polyether-modified silicone having a polyoxyalkylene portion, and the polyoxyalkylene portion of the polyether-modified silicone is contained. An ink composition for an oil-based marking pen, which is composed only of polyoxyethylene, has an average degree of polymerization in the range of 20 to 50, and has a melting point of 40 ° C. or higher for the polyether-modified silicone, is contained . The writing tool according to any one of claims 1 to 4, which is characteristic.

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