JP7636946B2 - Ballpoint pen - Google Patents

Description

The present invention relates to a ballpoint pen that transfers ink by rolling a transfer ball onto a writing surface.

Conventional inventions of this type include, for example, an aqueous ballpoint pen as described in Patent Document 1, which includes a transfer ball that rolls on the writing surface, a tip that rotatably holds the transfer ball, a barrel connected to the rear side of the tip, an ink absorbing body that holds ink within the barrel, and a relay core that is connected to the ink absorbing body and extends forward, with its front end in contact with the tip.
When the transfer ball is pushed backward by the writing pressure, the intermediate core is elastically deformed, forming a minute gap between the transfer ball and the inner surface of the crimped part of the tip. Therefore, the ink adhering to the outer surface of the transfer ball is ejected to the outside through the gap and transferred from the outer surface of the transfer ball to the surface to be written on.

Japanese Utility Model Application Publication No. 64-025180

Conventional ballpoint pens such as those described above can produce lines of uniform width without smudges over a long period of time. On the other hand, they cannot intentionally vary the line width or cause the lines to smudge, and may not be suitable for drawing pictures or patterns.

In view of the above problems, the present invention has the following configuration.
The ink supply unit includes a transfer ball that can roll on a writing surface, a cylindrical tip body that rotatably holds the transfer ball in an exposed state, and an ink supply unit that supplies ink to an outer peripheral surface of the transfer ball from the rear side within the tip body.
The transfer ball has an outer peripheral surface provided with a recess so as to be transferred to a writing surface ,
Within the tip body, an ink relay core that supplies ink to the transfer ball from the rear side, a receiving member that is movable relative to the ink relay core and receives the transfer ball from the rear side, and a biasing member that biases the receiving member forward are provided,
The ink relay core is positioned with a gap between it and the transfer ball, and comes into contact with the transfer ball when the transfer ball and the receiving member retract against the biasing force of the biasing member due to writing pressure .

The present invention is configured as described above, so it is possible to draw special lines, such as faded lines and lines of varying thickness.

1 is a full cross-sectional view showing an example of a ballpoint pen according to the present invention. FIG. 2 is an exploded perspective view showing the ballpoint pen with the core unit removed. FIG. 1A is an enlarged full cross-sectional view of the main part of the ballpoint pen when no writing pressure is applied, and FIG. 1B is an enlarged full cross-sectional view of the main part when writing pressure is applied. 1 is an enlarged image showing an example of a line drawn with the ballpoint pen. FIG. 11 is a perspective view showing another example of the transfer ball.

This embodiment discloses the following features.
The first feature is that it comprises a transfer ball capable of rolling on the surface to be written on, a cylindrical tip body that holds the transfer ball in an exposed, rotatable manner, and an ink supply section within the tip body that supplies ink to the outer peripheral surface of the transfer ball from the rear side, and a recess is provided on the outer peripheral surface of the transfer ball so that it can be transferred to the surface to be written on (see Figures 1 to 6).

The second feature is that the recesses are numerous micro recesses, and due to these numerous micro recesses, the surface roughness of the outer circumferential surface of the transfer ball is within the range of Ra 0.1 to 10 μm.

The third feature is that the transfer ball is made of synthetic resin material and has a diameter within the range of φ1.0 to φ15 mm.

The fourth feature is that the viscosity of the ink is within the range of 2 to 20 mPa·s.

The fifth feature is that the ink supply unit has an ink relay core made of a fiber bundle in close proximity to the transfer ball (see Figure 4(a)).

As a sixth feature, the tip body is provided with an ink relay core that supplies ink to the transfer ball from the rear side, a receiving member that can move forward and backward relative to the ink relay core and receives the transfer ball from the rear side, and a biasing member that biases the receiving member forward, the ink relay core is positioned with a gap between it and the transfer ball, and comes into contact with the transfer ball when the transfer ball and the receiving member are moved back against the biasing force of the biasing member due to writing pressure (see Figures 4(a) and (b)).

<Specific embodiment>
Next, specific embodiments having the above-mentioned features will be described in detail with reference to the drawings.

In this specification, the barrel axis direction means the direction along the barrel centerline, and the barrel circumferential direction means the direction around the barrel centerline. In addition, "front" means one side of the barrel axis direction in which the transfer ball protrudes, and "rear" means the opposite side to the one side.
In addition, in this specification, the radial direction of the barrel means the diameter direction of the barrel perpendicular to the center line of the barrel, the outer radial direction of the barrel means the direction away from the center of the barrel along the radial direction of the barrel, and the inner radial direction of the barrel means the direction toward the center of the barrel along the radial direction of the barrel.

This ballpoint pen 1 is a retractable ballpoint pen that includes a barrel 10, a core unit 20 that is housed in the barrel 10 and can move back and forth a predetermined distance, and a retractable operation mechanism 30 that advances the core unit 20 to lock the transfer ball 21 in a state where it protrudes from the barrel 10, or releases this locked state to retract the transfer ball 21 into the barrel 10.

The axle tube 10 is formed into a long tube shape extending in the front-to-rear direction from one or more cylindrical members. The illustrated axle tube 10 has a front axle 11 with an opening at the front end, and a rear axle 12 that is screwed to the rear end of the front axle 11 and extends rearward.

A locking portion 11a is provided on the inner peripheral surface of the front shaft 11 to lock the front end portion of the second biasing member 31. This locking portion 11a is a stepped portion whose diameter is reduced toward the front.

The inner circumferential surface of the rear axle 12 is provided with guide grooves and cam slopes (not shown) that engage with the rotor 32 and knock rod 33 of the retractable operating mechanism 30.

The core unit 20 integrally comprises a transfer ball 21 capable of rolling on the writing surface P, an approximately cylindrical tip body 22 which holds the transfer ball 21 in an exposed, rotatable manner, a receiving member 23 which receives the transfer ball 21 from the rear side, a first biasing member 24 which biases the receiving member 23 forward, and an ink supply section 25 which receives the receiving member 23 from the rear side and supplies ink to the outer peripheral surface of the transfer ball 21 from the rear side within the tip body 22.
This core unit 20 is detachable from the barrel 10 and can be replaced, and is sometimes called a ballpoint pen refill or the like.

The transfer ball 21 is a sphere made of a synthetic resin material and has a diameter set within a range of φ1.0 to 15 mm, and more preferably within a range of φ2 to 6 mm.
A large number of minute recesses are formed on the outer peripheral surface of the transfer ball 21 so as to be transferred to the writing surface P, and due to these large number of minute recesses, the surface roughness of the outer peripheral surface of the transfer ball 21 is in the range of Ra 0.1 to 10 μm.
According to the illustrated preferred example, the transfer ball 21 has a diameter of φ4 mm and a surface roughness of 3 μm.

The tip body 22 is formed in a long, generally cylindrical shape with an opening, and a ball house 22a that rotatably holds the transfer ball 21 is formed on the tip side.
The ball house 22a has an inner diameter that gradually narrows toward the front, and its front end is formed to be smaller than the outer diameter of the transfer ball 21. The inner edge of this front end contacts the front half of the outer circumferential surface of the transfer ball 21.
The inner peripheral surface of the ball house 22a behind the front end portion is a surface that is free of irregularities, projections, steps, and the like.

The receiving member 23 is a cylindrical member that moves a predetermined distance along the inner circumferential surface of the tip body 22, and its front end receives the rear half of the transfer ball 21 in an annular shape. This receiving member 23 can move forward and backward relative to the ink relay core 25a inserted inside.

The transfer ball 21, the chip body 22, and the receiving member 23 are formed from a hard resin material with excellent abrasion resistance, such as polyacetal resin (POM). As another example, the transfer ball 21, the chip body 22, and the receiving member 23 can be formed in part or in whole from a metal material.

The first biasing member 24 is a compression coil spring that biases the receiving member 23 forward. The first biasing member 24 is fitted in an annular shape to the front end side of the cylindrical connecting member 25b so as to surround the periphery of the ink relay core 25a in an annular shape.
The first biasing member 24 has a front end in contact with the rear end of the receiving member 23, and has a rear end engaged with the cylindrical connecting member 25b.

The ink supply unit 25 is integrally equipped with an ink relay core 25a adjacent to the chip body 22 from the rear side, a cylindrical connection member 25b inserted into and connected to the chip body 22, an ink storage core 25c that stores ink to be supplied to the ink relay core 25a, and a cylindrical case 25d that cylindrically covers the ink storage core 25c.

The ink relay core 25a is a fiber bundle made of a large number of synthetic fibers in the shape of an elongated shaft. The front end side of the ink relay core 25a is formed in a tapered bullet shape.
A gap s is provided between the front end of the ink relay core 25a and the transfer ball 21. This gap s narrows when the transfer ball 21 retracts (see FIG. 4).
The ink relay core 25a passes through the cylindrical connecting member 25b in the front-rear direction. The rear end of the ink relay core 25a is press-fitted into the front end of the ink storage core 25c.

The tubular connecting member 25b is made of a hard synthetic resin material (e.g., polypropylene resin (PP)) and is formed into a generally cylindrical shape extending in the front-rear direction. This tubular connecting member 25b holds the ink relay core 25a inserted therethrough, and receives the receiving member 23 from the rear side at its front end when it is retracted.

To explain in more detail, the inner peripheral surface of this cylindrical connecting member 25b is provided with an annular protrusion 25b1 (see Figure 4) that is pressed against the outer peripheral surface of the ink relay core 25a to hold the ink relay core 25a in an immovable state.

Further, a first locking portion 25b2 that receives the rear end portion of the first biasing member 24 and a second locking portion 25b3 that receives the rear end portion of the second biasing member 31 are provided on the outer circumferential surface of the tubular connecting member 25b.
The first locking portion 25b2 is a stepped portion formed in an annular shape on the outer circumferential surface of the tubular connecting member 25b.
The second locking portion 25b3 is an annular projection that protrudes radially outward from the rear end side of the outer circumferential surface of the cylindrical connecting member 25b.

The rear half of the cylindrical connection member 25b (more specifically, between the first locking portion 25b2 and the second locking portion 25b3) is press-fitted into the inner circumferential surface of the tip body 22 and is integrated with the tip body 22.

The ink reservoir core 25c is a thin-walled synthetic resin cylinder containing a number of synthetic fibers, which are impregnated with ink, and is sometimes called a wadding. The viscosity of the ink is set within the range of 2 to 20 mPa·s.
The ink in the ink storage core 25c flows to the ink relay core 25a by capillary force.

The cylindrical case 25d is formed as a long, bottomed cylinder with the rear end at the bottom. This cylindrical case 25d covers the entire length of the ink storage wick 25c and is attached in a ring shape to the cylindrical connection part 25b4 on the rear end side of the cylindrical connection member 25b.

The retractable operating mechanism 30 comprises a second biasing member 31 which biases the core unit 20 rearward, a rotor 32 which moves back and forth and rotates behind the core unit 20, and a knock rod 33 which moves back and forth behind the rotor 32. When the knock rod 33 is pushed forward, the rotor 32 and the core unit 20 etc. move forward and rotate to engage with an engaging portion (not shown) on the inner surface of the shaft tube 10, and when the knock rod 33 is pushed forward again, the engaged state is released and the rotor 32 and the core unit 20 etc. are retracted.
For these, for example, the structure described in JP 2018-149787 A can be applied.

The second biasing member 31 is a compression coil spring that fits annularly around the tip body 22, with its front end engaged with the shaft tube 10 and its rear end engaged with the cylindrical connecting member 25b, biasing the core unit 20 backward. The biasing force of this second biasing member 31 is greater than the biasing force of the first biasing member 24.

Next, the characteristic functions and effects of the ballpoint pen 1 having the above configuration will be described in detail.
1, the tip end of the tip body 22 and the transfer ball 21 are located inside the barrel 10. When the knock rod 33 is pushed forward, the rotor 32 and the core unit 20 move forward against the biasing force of the second biasing member 31, causing the tip end of the tip body 22 and the transfer ball 21 to protrude forward from the barrel 10, and the rotor 32 is locked in this protruding state.

When no pen pressure is applied to the transfer ball 21, a gap s is maintained between the transfer ball 21 and the ink relay core 25a, as shown in FIG. 4(a).

When writing pressure is applied to the transfer ball 21, as shown in Figure 4 (b), the transfer ball 21 and the receiving member 23 move back against the urging force of the first urging member 24, the transfer ball 21 is pressed against the front end of the ink relay core 25a, and ink flows from the ink relay core 25a to the outer peripheral surface of the transfer ball 21.
As the transfer ball 21 rotates, the ink adhering to the outer peripheral surface of the transfer ball 21 exits the tip body 22 through the gap between the transfer ball 21 and the front end of the ball house 22a, and is transferred from the outer peripheral surface of the transfer ball 21 to a writing surface P such as paper.

During this transfer, due to the numerous minute recesses on the outer circumferential surface, the transfer ball 21 has parts that are pressed strongly against the writing surface P, parts that are pressed weakly, parts that are pressed over a wide area, and parts that are pressed over a narrow area.
As a result, the ink transferred to the writing surface P becomes a special writing line L having dark areas, faded areas, thick areas, thin areas, etc., in other words, a writing line L that looks like it was drawn with a crayon (see Figure 5).

After this, when the transfer ball 21 is pulled away from the writing surface P and the writing pressure is released, the transfer ball 21 and the receiving member 23 move forward due to the biasing force of the first biasing member 24, and the front half of the transfer ball 21 is pressed against the inward edge of the front end of the ball house 22a, forming a gap s between the transfer ball 21 and the ink relay core 25a that prevents the flow of ink (see Figure 4(a)).

This reduces the dripping phenomenon, in which excessive ink flows out from the front end of the tip body 22.

In addition, when the ink runs out, the rear barrel 12 can be removed from the front barrel 11 and the core unit 20 can be easily replaced (see Figure 2).

<Modification>
According to the above embodiment, the outer peripheral surface of the transfer ball 21 is processed to have a predetermined surface roughness, thereby forming a large number of recesses on the outer peripheral surface of the transfer ball 21. As another example, it is also possible to form the recesses using letters, figures, patterns, etc.
A transfer ball 21' shown in FIG. 6 has a plurality of recesses 21a arranged in a regular hexagonal pattern on its outer circumferential surface, and has an appearance similar to that of a soccer ball.
In the ballpoint pen 1, if the transfer ball 21 is replaced with a transfer ball 21', a special writing line can be drawn by the plurality of recesses 21a.

In addition, according to the above embodiment, ink is supplied to the transfer ball 21 from the ink relay core 25a and the ink storage core 25c, but as another example, it is also possible to construct the ink relay core 25a and the ink storage core 25c integrally from a fiber bundle.

In addition, according to the above embodiment, a retractable ballpoint pen is constructed, but the structure of the core unit 20 can also be applied to ballpoint pens that are not retractable, such as cap-type ballpoint pens.

The present invention is not limited to the above-described embodiments, and may be modified as appropriate without departing from the spirit and scope of the present invention.

1: Ballpoint pen 10: Barrel 20: Core unit 21, 21': Transfer ball 21a: Recess 22: Tip body 23: Receiving member 24: First biasing member 25: Ink supply section 25a: Ink relay core 25b: Cylindrical connecting member 25c: Ink storage core 25d: Cylindrical case 30: Protruding and retracting operation mechanism P: Writing surface

Claims (4)

The ink cartridge includes a transfer ball that can roll on a writing surface, a cylindrical tip body that rotatably holds the transfer ball in an exposed state, and an ink supply unit that supplies ink to an outer peripheral surface of the transfer ball from the rear side within the tip body,
The transfer ball has an outer peripheral surface provided with a recess so as to be transferred to a writing surface ,
Within the tip body, an ink relay core that supplies ink to the transfer ball from the rear side, a receiving member that is movable relative to the ink relay core and receives the transfer ball from the rear side, and a biasing member that biases the receiving member forward are provided,
The ink relay core is positioned with a gap between it and the transfer ball, and comes into contact with the transfer ball when the transfer ball and the receiving member retract against the biasing force of the biasing member due to writing pressure . The ballpoint pen according to claim 1, characterized in that the recesses are numerous micro recesses, and the surface roughness of the outer circumferential surface of the transfer ball is within the range of Ra 0.1 to 10 μm due to the numerous micro recesses. The ballpoint pen according to claim 1 or 2, characterized in that the transfer ball is made of a synthetic resin material and has a diameter within the range of φ1.0 to φ15 mm. 4. The ballpoint pen according to claim 1, wherein the ink supply section includes an ink relay core made of a fiber bundle in close proximity to the transfer ball.

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