CN116457216A

CN116457216A - Ball-point pen nib, ball-point pen refill and ball-point pen

Info

Publication number: CN116457216A
Application number: CN202180074895.1A
Authority: CN
Inventors: 梶原巧; 桝重直登
Original assignee: Pilot Corp
Current assignee: Pilot Corp
Priority date: 2020-11-16
Filing date: 2021-11-15
Publication date: 2023-07-18
Anticipated expiration: 2041-11-15
Also published as: CN116457216B

Abstract

A ball point pen tip (40) is provided with a ball (42) having a diameter of 0.5mm or less and a pen tip body (50) holding the ball, wherein the pen tip body has a ball holding chamber (52) holding the ball, and a ball holding chamberThe ink flow channel (64) extending from the ink flow channel in the radial direction (dr) and opening in the ball holding chamber and not reaching the rear hole, the ratio (A/B) of the ink consumption A per 100m of handwriting to the diameter B of the ball is 200mg/mm or more and 800mg/mm or less, the front end (64 a) of the ink flow channel is used as a starting point S1, and the volume of the ink flow channel from the starting point to the end point and the 1 st Space (SA) in the ink flow channel is 0.02mm when the position 0.3mm rearward from the front end (62 a) of the ink flow channel is used as an end point S2 ³ The above.

Description

Ball-point pen nib, ball-point pen refill and ball-point pen

Technical Field

The present invention relates to a ballpoint pen tip, a ballpoint pen refill, and a ballpoint pen.

Background

Conventionally, a ball point pen tip having a ball and a tip body holding the ball has been used for a ball point pen.

JP2002-52884A discloses a ballpoint pen tip and a ballpoint pen provided with the ballpoint pen tip, the ballpoint pen tip comprising: a ball holding chamber for receiving a ball; a rear hole located at the rear of the ball holding chamber; an ink guide hole communicating the ball holding chamber with the rear hole; and an ink tank extending in a radial direction from the ink guide hole.

In the case of a conventional ball point pen which is left for a long period of time without writing, ink may be dried and cured in a ball holding chamber. In this case, there is a problem that ink is not properly supplied to the ball, the handwriting is off-white, or writing is not possible at all. Therefore, it is desirable that the ink in the ball-point pen tip be prevented from drying out in the ball-holding chamber even when the ink is left for a long period of time without writing.

Disclosure of Invention

The present invention has been made in view of this point, and an object of the present invention is to suppress drying of ink at a pen point of a ball point pen.

The ball-point pen nib of the present invention comprises a ball having a diameter of 0.5mm or less and a nib body holding the ball,

the pen tip body includes:

a ball holding chamber for holding the ball;

a rear hole located at the rear of the ball holding chamber;

an ink flow hole that communicates the ball holding chamber with the rear hole; and

an ink flow groove extending radially from the ink flow hole, opening in the ball holding chamber, and not reaching the rear hole,

when the ink consumption per 100m writing is A (mg) and the diameter of the ball is B (mm), the ratio (A/B) of the ink consumption A to the diameter B of the ball is 200mg/mm or more and 800mg/mm or less,

When the front end of the ink flow channel is set as a starting point and a position 0.3mm rearward from the front end of the ink flow channel is set as an ending point, the volume of the space between the ink flow channel and the ink flow channel from the starting point to the ending point is 0.02mm ³ The above.

In the ball-point pen tip of the present invention,

the volume of the ink flow hole and the space in the ink flow channel from the start point to the end point may be 1.5 times or more the volume of the space from the tip end of the pen point main body to the start point in the ball holding chamber.

In the ball-point pen tip of the present invention,

the inner diameter of the ink flow hole may be 40% or more of the diameter of the ball.

In the ball-point pen tip of the present invention,

the length of the ink flow hole may be 90% or less of the diameter of the ball.

In the ball-point pen tip of the present invention,

the length of the region of the ink flow hole where the ink flow groove is not formed may be 90% or less of the diameter of the ball.

The ballpoint pen tip according to the present invention may further include a rebound member having a spring portion and a stem portion extending forward from the spring portion and abutting against the ball from the rear.

In the ball-point pen tip of the present invention,

the movable range of the ball with respect to the pen tip main body in the front-rear direction may be 0.015mm or more and 0.06mm or less.

The ball-point pen refill of the present invention comprises:

the above-mentioned ball-point pen nib; and

an ink containing cylinder that contains ink.

In the ball-point pen refill of the present invention,

the ink may be a thermochromic ink.

The ball-point pen of the present invention is provided with the ball-point pen refill.

According to the present invention, drying of ink at the pen point of a ball point pen can be suppressed.

Drawings

Fig. 1 is a view for explaining embodiment 1 of the present invention, and is a longitudinal sectional view showing an example of a ballpoint pen in which a ballpoint pen refill having a ballpoint pen tip is incorporated.

Fig. 2 is a longitudinal sectional view of the ball-point pen tip of fig. 1 enlarged.

Fig. 3 is a longitudinal sectional view showing the vicinity of the tip of the ballpoint pen tip in further enlarged form.

Fig. 4 is a cross-sectional view corresponding to the IV-IV line of fig. 3.

Fig. 5 is a graph showing the calculation results of the volumes of the ink flow holes and the space portions in the ink flow grooves of the ballpoint pen tip.

Fig. 6 is a view for explaining embodiment 2, and is a longitudinal sectional view showing an example of a ballpoint pen in which a ballpoint pen refill having a ballpoint pen nib is incorporated.

Fig. 7 is a longitudinal sectional view of the ballpoint pen tip of fig. 6 enlarged.

Fig. 8 is a longitudinal sectional view showing the vicinity of the tip of the ballpoint pen tip of fig. 6 further enlarged.

Fig. 9 is a cross-sectional view corresponding to line IX-IX of fig. 8.

Detailed Description

Embodiments of the present invention will be described below with reference to the drawings. In the drawings attached to the present specification, the scale, aspect ratio, and the like of the object are appropriately changed and exaggerated for convenience of illustration and understanding.

The terms such as "parallel", "orthogonal", "identical", and the like, values of length and angle, and the like, which are used in the present specification to determine the shape and geometry, and the degree thereof, are not limited by strict meanings, but are interpreted to include a range of degrees to which the same function can be expected.

In the present specification, the direction in which the central axis a of the ballpoint pen 10 extends (the longitudinal direction, the vertical direction in the vertical sectional view) is referred to as the axial direction da, the direction orthogonal to the central axis a is referred to as the radial direction dr, and the direction along the circumference around the central axis a is referred to as the circumferential direction dc. In the axial direction da, a side closer to a surface to be written such as a paper surface during writing is referred to as a front side, and a side farther from the surface to be written is referred to as a rear side. That is, the pen point side is the front and the opposite side is the rear.

Embodiment 1

Fig. 1 is a view for explaining embodiment 1 of the present invention, and is a sectional view showing an example of a ballpoint pen 10. In this embodiment, an example will be described in which the ballpoint pen 10 is a so-called side-pressure ballpoint pen. The ballpoint pen 10 includes a shaft 20, a ballpoint pen refill 30 assembled in the shaft 20, a telescopic mechanism 12 for telescopic a tip of the ballpoint pen refill 30 from the shaft 20, a friction member 14 for rubbing handwriting, and a clip 16.

The shaft tube 20 includes a front shaft 21, a rear shaft 25 coupled to the front shaft 21, a rear end cover 28 attached to a rear end portion of the rear shaft 25, and a grip member 29 disposed so as to surround an outer surface of the front shaft 21. The front shaft 21 has: an opening 22 provided at the tip end, the tip end of the ballpoint pen tip 40 of the ballpoint pen refill 30 being retractable; a 1 st engaging portion 23 provided on an inner surface of the front region; and an external thread portion 24 provided on an outer surface of the rear region. The rear shaft 25 has a female screw portion 26 provided on the inner surface of the front region. The front shaft 21 and the rear shaft 25 are coupled to each other by screwing the male screw portion 24 of the front shaft 21 and the female screw portion 26 of the rear shaft 25. A rear end cover 28 is fitted to the rear end portion of the rear shaft 25. The grip member 29 is intended for grasping with the fingers when a user writes with the ballpoint pen 10. The front shaft 21, the rear shaft 25, and the rear end cover 28 are formed of, for example, resin, and the grip member 29 is formed of, for example, rubber.

In the present embodiment, the clip 16 functions as an operation portion that is operated by a user when pressed. The shaft tube 20 is provided with a slide hole 27 extending in the axial direction da and penetrating a wall portion of the shaft tube 20. The slide hole 27 is provided so as to span the rear region of the rear shaft 25 and the front end portion of the rear end cover 28. In the illustrated example, clip 16 extends from inside shaft 20 to outside shaft 20 through sliding aperture 27. The movement range of the clip 16 in the axial direction da may be defined by the front end and the rear end of the slide hole 27.

The ballpoint pen refill 30 is telescopically received in the barrel 20. The ballpoint pen refill 30 includes an ink containing cylinder 32 containing ink, a pen tip holder 34 disposed in front of the ink containing cylinder 32, and a ballpoint pen tip 40 disposed in front of the pen tip holder 34. In the example shown in fig. 1, the rear end portion of the pen tip holder 34 is inserted into the front end portion of the ink containing cylinder 32, and the rear end portion of the ballpoint pen tip 40 is inserted into the front end portion of the pen tip holder 34. The ballpoint pen refill 30 has a 2 nd engaging portion 36 provided on the outer surface of the front region. In the illustrated example, the 2 nd engaging portion 36 is provided on the outer surface of the pen tip holder 34. In a state where the ballpoint pen refill 30 is mounted, the 2 nd engaging portion 36 of the ballpoint pen refill 30 is located further rearward than the 1 st engaging portion 23 of the front shaft 21, and the coil spring 18 is arranged in a compressed state between the 1 st engaging portion 23 and the 2 nd engaging portion 36. Thereby, the coil spring 18 biases the ball-point pen refill 30 rearward.

As the ink, an ink usable for a ballpoint pen can be used without particular limitation. As an example, a thermochromic ink may be used as the ink. The thermochromic ink may be a reversible thermochromic ink. As an example of the reversible thermochromic ink, a reversible thermochromic ink that changes from a color development state to a color development state by heating and changes from a color development state to a color development state by cooling may be used.

Specifically, general-purpose inks such as an aqueous gel ink having shear thinning properties, a low-viscosity aqueous ink, a low-viscosity oily ink, a high-viscosity oily ink, and an emulsion ink can be applied according to the type of the pen point of the ball point pen. Among them, aqueous gel inks having shear thinning properties are particularly effective.

In addition, in the aqueous gel ink having shear thinning properties, the coloring material is not particularly limited, and dyes, pigments, metallic luster pigments, fluorescent pigments, titanium oxide, thermochromic pigments, and the like can be used. In particular, when the ink contains 10 wt% or more of the pigment solid content, the ink tends to dry and solidify in the pen tip of the ballpoint pen, and therefore the effect of the present embodiment can be further exhibited. Further, when titanium oxide, which is a pigment solid content of 10 wt% or more, is used as the ink, the effect of the present embodiment can be further exhibited.

In an aqueous gel ink having shear thinning properties, the viscosity is at 20℃and at a shear rate of 3.84sec ^-1 Preferably 1 to 2000 mPas, more preferably 3 to 1500 mPas, and even more preferably 500 to 1000 mPas. In addition, at a shear rate of 384sec in an environment of 20 ℃ ^-1 Since the ink discharge property of the pen tip of the ball-point pen is good when measured under the conditions of (a), the viscosity is preferably 1 to 200 mPas, more preferably 10 to 100 mPas, and even more preferably 20 to 50 mPas.

The viscosity was measured using a rheometer [ product name, manufactured by tansfuments corporation: discovery HR-2, cone plate (diameter 40mm, angle 1 degree)]The ink was placed in an environment at 20℃and a shear rate of 3.84sec ^-1 Or shear rate 384sec ^-1 Is determined under the conditions of (a) and (b).

When the ink composition of the present invention is filled into a water-based ballpoint pen, the ball diameter (diameter) and the ink consumption amount preferably satisfy a specific relationship. Specifically, when the ink consumption per 100m of the water-based ballpoint pen is A (mg) and the ball diameter is B (mm), the relationship of 200.ltoreq.A/B.ltoreq.800 is preferable, and the relationship of 300.ltoreq.A/B.ltoreq.700 is more preferable. This is because, by setting the ink consumption amount in an appropriate range with respect to the ball diameter, the ink fluidity can be improved, the writing can be suppressed from being whitened, and the good writing can be easily obtained.

The rubbing member 14 of the present embodiment is a member for rubbing handwriting generated by ink. In the case where the ink is a thermochromic ink, the friction member 14 may be a friction member having the following functions: the writing surface such as paper on which handwriting is formed is rubbed, and the ink on which handwriting is formed is heated by frictional heat. In this case, the friction member 14 may be formed of an elastic material, for example. The friction member 14 may be fixed to the rear cover 28 by press fitting, engagement, screwing, fitting, adhesion, two-color molding, or the like. In the case where the ink is ink having no thermochromic property, the friction member 14 may be, for example, a member that rubs a writing surface such as paper on which handwriting is formed to remove the handwriting, and is, for example, a frosted rubber.

The telescopic mechanism 12 is a mechanism for alternately switching the ballpoint pen 10 between a pressed state in which the tip end of the ballpoint pen tip 40 protrudes from the opening 22 of the front shaft 21 and a non-pressed state in which the tip end of the ballpoint pen tip 40 is immersed from the opening 22. In fig. 1, the ballpoint pen 10 is shown in a pressed state. In the non-pressed state, the ball-point pen refill 30 is pushed rearward by the repulsive force of the coil spring 18, and the tip end portion of the ball-point pen nib 40 is thereby retracted from the opening portion 22. When the user presses and slides the clip 16 forward with his/her finger, the ballpoint pen refill 30 moves forward, and the tip end portion of the ballpoint pen nib 40 protrudes forward from the opening portion 22. Even if the user separates his/her finger from the clip 16, the ballpoint pen refill 30 maintains a state in which the tip end portion of the ballpoint pen tip 40 protrudes forward from the opening portion 22. Again, when the user presses and slides the clip 16 forward with his finger, the ballpoint pen refill 30 moves forward only a small distance. When the user releases his/her finger from the clip 16 or releases the pressing force to the clip 16 in the forward direction, the ballpoint pen refill 30 is pushed rearward by the elastic repulsive force of the coil spring 18, and the tip end portion of the ballpoint pen nib 40 is immersed in the opening portion 22. The telescopic mechanism 12 for realizing such a telescopic operation is well known, and therefore, a detailed description thereof will be omitted. As an example, the telescopic mechanism 12 disclosed in japanese patent application laid-open No. 2012-6315 can be used.

The ballpoint pen tip 40 will be further described with reference to fig. 2 to 4. Fig. 2 is a longitudinal sectional view showing the ballpoint pen tip 40 in an enlarged manner, fig. 3 is a longitudinal sectional view showing the vicinity of the tip of the ballpoint pen tip 40 in a further enlarged manner, and fig. 4 is a cross sectional view corresponding to the line IV-IV in fig. 3.

The ball-point pen nib 40 includes a ball 42 and a nib body 50 holding the ball 42. The pen tip body 50 is formed of a metal material such as stainless steel. In view of corrosion resistance and the like, the nib body 50 is preferably formed of stainless steel. The ball 42 is made of a metal material such as a tungsten carbide-based superhard material. The diameter of the beads 42 may be, for example, more than 0mm and 0.5mm or less. Preferably, the diameter of the beads 42 may be 0.2mm or more and 0.5mm or less. The pen tip body 50 has a function of guiding the ink contained in the ink containing cylinder 32 toward the ball 42. At the time of writing, the user moves on the surface to be written in a state where the ball 42 is pressed against the surface to be written of paper or the like, whereby the ball 42 rotates on the surface to be written. Thereby, the ink adhering to the ball 42 is transferred to the surface to be written. Then, handwriting is formed on the written surface by the transferred ink. When an aqueous shear thinning ink whose viscosity is reduced by the rotation of the ball 42 is used as the ink, the ink adhering to the ball 42 permeates into the surface to be written as the ball 42 rotates on the surface to be written. Then, handwriting is formed on the written surface by the permeated ink.

The pen tip body 50 is manufactured by cutting, for example. At this time, if burrs or the like generated by cutting during manufacturing remain on the inner surface of the pen tip body 50, the burrs may obstruct the flow of ink in the pen tip body 50. In order to solve this problem, it is conceivable to clean the inner surface of the pen tip body 50 after manufacturing the pen tip body 50 by cutting. By this cleaning, burrs are removed, and the surface roughness (arithmetic average roughness Ra) of the inner surface of the nib body 50 is reduced, and the inner surface is mirrored. However, as a result of the study by the present inventors, even when the inner surface of the pen tip main body 50 is cleaned, there is a case where the flow of ink in the pen tip main body 50 cannot be significantly improved. This is presumably because, in the case of using an aqueous ink such as an aqueous ink or an aqueous shear thinning ink as the ink, in stainless steel, the contact angle of the ink on the surface becomes large and the ink diffusion is suppressed, and the ink easily flows in the surface having a surface roughness larger than that of a mirror surface having a surface roughness such as an arithmetic average roughness Ra of less than 10 nm. Accordingly, at least 1 of the inner surface constituting the 1 st space portion SA described later, the inner surface constituting the 2 nd space portion SB described later, and the inner surface constituting the 3 rd space portion SC described later in the pen tip main body 50 has a surface roughness of JIS B0601: the arithmetic average roughness Ra meter specified in 2013 is preferably 10nm to 1 μm, more preferably 100nm to 500nm, and still more preferably 100nm to 150 nm.

The ballpoint pen tip 40 of the present embodiment has a rebound member 44 for urging the ball 42 forward. In the example shown in fig. 2, the rebound member 44 includes a spring portion 46 and a rod portion 48 extending forward from the spring portion 46 and abutting the ball 42 from the rear. The spring portion 46 is constituted by a coil spring, for example. The rear end of the lever 48 is connected to the spring 46, and the front end of the lever 48 contacts the ball 42 from behind. In the illustrated example, the rear end of the spring 46 abuts against the pen tip holder 34. In this state, the spring 46 is in a compressed state, and a force is generated in a direction in which the spring 46 extends. The lever portion 48 transmits the force of the spring portion 46 to the ball 42. Thus, the force that biases the ball 42 forward always acts on the ball 42. The diameter D2 of the stem 48 may be, for example, 0.01mm to 0.3 mm. Preferably, the diameter D2 may be 0.05mm or more and 0.2mm or less.

The pen tip body 50 has a ball holding chamber 52, a rear hole 57, an ink flow through hole 62, and an ink flow through groove 64. The ball holding chamber 52 has a function of holding the ball 42, and also has a function of holding ink in the ball holding chamber 52 and attaching the ink to the ball 42. The ball holding chamber 52 is formed by a hole formed rearward from the front end of the pen tip body 50. The ball holding chamber 52 has a rear wall 54. The rear wall 54 is a wall defining a rear portion of the ball holding chamber 52. The center axis of the pen tip body 50 coincides with the center axis a of the ballpoint pen 10. Therefore, in this specification, the center axis of the pen tip body 50 may be referred to as the center axis a. After the ball 42 is placed in the ball holding chamber 52, the ball 42 is held by the ball holding chamber 52 by caulking so that the tip end portion of the pen tip main body 50 deforms inward (toward the center axis a side). Therefore, the pen tip body 50 has a caulking portion 56 at the tip end portion that deforms toward the inside (the central axis a side).

The ball 42 is movable in the front-rear direction in the ball holding chamber 52. In fig. 3, the ball 42 located at the rearmost position in the ball holding chamber 52 is indicated by a solid line, and the ball 42 located at the foremost position in the ball holding chamber 52 is indicated by a two-dot chain line. When not writing, the ball 42 is positioned at the forefront in the ball holding chamber 52 by the urging force of the rebound member 44, and abuts against the caulking portion 56 of the pen tip main body 50. At this time, the gap between the ball 42 and the caulking portion 56 is sealed. This suppresses the outflow of ink during non-writing and also suppresses the drying of ink in the ball holding chamber 52. When writing with the ballpoint pen 10, since a rearward force generated by the pen pressure acts on the ball 42, the ball 42 moves rearward against the urging force of the rebound member 44, and a gap is generated between the ball 42 and the caulking portion 56. By rotating the ball 42 on the surface to be written, the ink adhering to the ball 42 is carried from the ball holding chamber 52 to the surface to be written through the gap, and adheres to the surface to be written. When the ball 42 is positioned rearmost in the ball holding chamber 52, the ball 42 abuts against a junction portion of the rear wall 54 and the ink flow hole 62 (a front end 62a of the ink flow hole 62). The movable range (gap) C of the ball 42 with respect to the pen tip body 50 in the front-rear direction may be, for example, 0.015mm or more and 0.06mm or less. Preferably, the movable range C of the beads 42 may be 0.020mm or more and 0.05mm or less.

The rear hole 57 is located rearward of the ball holding chamber 52, and extends in the axial direction da. The rear hole 57 communicates with the ink containing cylinder 32 via the pen tip holder 34, and functions as a flow path of ink from the ink containing cylinder 32 toward the ball holding chamber 52. The rear hole 57 is formed by a hole portion formed forward from the rear end of the pen tip main body 50. The rear hole 57 includes a hole portion formed in a cylindrical shape. The central axis of the rear hole 57 coincides with the central axis a of the nib body 50. The rear hole 57 includes a plurality of cylindrical hole portions having different diameters, and the diameter of each cylindrical hole portion increases rearward.

The ink flow through hole 62 is located between the ball holding chamber 52 and the rear hole 57, and communicates the ball holding chamber 52 with the rear hole 57. The ink flow through hole 62 extends in a straight line in the axial direction da. In the illustrated example, the ink flow hole 62 is a through hole having a cylindrical shape. The ink flow hole 62 functions as a flow path of ink from the rear hole 57 toward the ball holding chamber 52. The inner diameter (diameter) D1 of the ink flow hole 62 may be, for example, 40% to 90% of the diameter of the ball 42. Preferably, the inner diameter D1 may be 50% to 80% of the diameter of the ball 42. The inner diameter D1 may be, for example, 0.2mm to 0.45 mm. Preferably, the inner diameter D1 may be 0.25mm or more and 0.4mm or less. The center axis of the ink flow hole 62 coincides with the center axis a of the pen tip main body 50. Accordingly, the distance R1 from the central axis a of the pen tip main body 50 to the peripheral wall of the ink flow hole 62 coincides with the radius of the ink flow hole 62.

The length L1 of the ink flow hole 62 may be, for example, 0% or less than 90% of the diameter of the ball 42. Preferably, the length L1 may be 40% to 80% of the diameter of the ball 42. The length L1 may be, for example, more than 0mm and 0.45mm or less. Preferably, the length L1 may be 0.2mm or more and 0.4mm or less. Here, the length L1 of the ink flow hole 62 is a length in the axial direction da from the front end 62a of the ink flow hole 62 to the rear end 62b of the ink flow hole 62. In the illustrated example, the front end 62a of the ink flow hole 62 is the portion located at the forefront among the portions having the inner diameter D1, and the rear end 62b of the ink flow hole 62 is the portion located at the rearmost among the portions having the inner diameter D1. When the ball 42 is positioned rearmost in the ball holding chamber 52, the tip 62a of the ink flow hole 62 abuts against the ball 42. If the ink flow hole 62 has such a size D1 and/or L1, the flow amount of the ink through the ink flow hole 62 can be appropriately ensured.

The ink flow grooves 64 extend from the ink flow holes 62 in the radial direction dr and open into the ball holding chamber 52. The ink circulation groove 64 communicates with the ink circulation hole 62 and the ball holding chamber 52. On the other hand, the ink flow channel 64 does not reach the rear hole 57. The front end 64a of the ink flow channel 64 is located at the rear wall 54 of the ball holding chamber 52. In addition, the rear end 64b of the ink flow channel 64 is located at the peripheral wall of the ink flow channel 62. By providing the pen tip body 50 with such an ink flow channel 64, even when the ball 42 is positioned rearmost in the ball holding chamber 52 and abuts against the front end 62a of the ink flow channel 62 (see fig. 3), a gap is formed between the ball 42 and the front end 64a of the ink flow channel 64, and ink can flow from the ink flow channel 62 to the ball holding chamber 52 via the ink flow channel 64.

The ink flow channel 64 has a peripheral wall 66 facing the ink flow channel 62. The peripheral wall 66 is a wall that defines the outer contour of the ink flow channel 64 in the radial direction dr. The peripheral wall 66 includes a main portion 67 and an inclined portion 68 located rearward of the main portion 67. In the example shown in fig. 3 and 4, the main portion 67 extends in both the axial direction da and the circumferential direction dc. The inclined portion 68 connects the main portion 67 and the ink flow through hole 62. The inclined portion 68 extends in a direction inclined with respect to both the axial direction da and the radial direction dr so as to approach the ink flow hole 62 toward the rear. The distance R2 from the central axis a of the pen tip main body 50 to the peripheral wall 66 (main portion 67) of the ink flow channel 64 may be, for example, 40% to 200% of the diameter of the ball 42. Preferably, the distance R2 may be 60% to 150% of the diameter of the ball 42. The distance R2 may be, for example, 0.2mm to 1 mm. Preferably, the distance R2 may be 0.3mm or more and 0.7mm or less.

As described above, the ink circulation groove 64 does not reach the rear hole 57. Therefore, the ink flow hole 62 has a region where the ink flow groove 64 is not formed behind the ink flow groove 64. This region is a region where the area of the cross section orthogonal to the central axis a is smallest in the flow path of the ink from the rear hole 57 to the ball holding chamber 52. According to the study of the present inventors, the length of the region in the axial direction da affects the flow rate of ink in the flow path of ink in the pen tip main body 50. In the pen tip main body 50, in order to ensure an appropriate ink flow rate, the length L2 of the region of the ink flow through hole 62 where the ink flow groove 64 is not formed may be, for example, 20% to 80% of the diameter of the ball 42. Preferably, the length L2 may be 40% to 60% of the diameter of the ball 42. The length L2 may be, for example, 0.1mm to 0.4 mm. Preferably, the length L2 may be 0.2mm or more and 0.3mm or less. The length L2 is defined as the length from the rear end 64b of the ink circulation groove 64 to the rear end 62b of the ink circulation hole 62.

The width W of the ink flow channel 64 in the direction perpendicular to both the axial direction da and the radial direction dr may be, for example, 0.01mm to 0.15 mm. Preferably, the width W may be 0.05mm or more and 0.1mm or less.

The pen tip body 50 has 1 ink circulation groove 64 or a plurality of ink circulation grooves 64. In the case where the pen tip body 50 has a plurality of ink flow grooves 64, the ink flow grooves 64 may be arranged to have equal angular intervals from each other in the circumferential direction dc. In the example shown in fig. 4, the pen tip body 50 has 4 ink circulation grooves 64 arranged at equal angular intervals in the circumferential direction dc.

As described above, when the conventional ball point pen is left for a long period of time without writing, the ink may be dried and cured in the ball holding chamber. In this case, there is a problem that ink is not properly supplied to the ball, the handwriting is off-white, or writing is not possible at all. As a result of intensive studies on a method of improving this problem, the inventors have found that, when the volumes of the ink flow through hole 62 and the space portion (1 st space portion) SA in the ink flow through groove 64 measured rearward from the front end 64a of the ink flow through groove 64 are equal to or greater than a predetermined value, drying of the ink in the ball holding chamber 52 can be effectively suppressed. Hereinafter, the space portion SA will be described.

The front end 64a of the ink flow channel 64 is set as the start point S1 of the space portion SA. The end point S2 is a position at which the distance L3 measured from the front end 62a of the ink flow hole 62 to the rear is 0.3 mm. Then, the volumes of the ink flow holes 62 and the space portions SA in the ink flow grooves 64 from the start point S1 to the end point S2 are defined. In fig. 3, L4 denotes the length of the space portion SA in the axial direction da from the start point S1 to the end point S2.

The space portion SA is defined by the following conditions. The ball 42 is positioned rearmost in the ball holding chamber 52 and is in contact with the tip 62a of the ink flow hole 62. In this case, a part of the ball 42 is located in the ink flow hole 62. The space within the ball holding chamber 52 is not included in the space portion SA. Even if located within the length L4, the portion not filled with ink is not included in the space portion SA. The portions not filled with the ink are, for example, the portion occupied by the ball 42 and the portion occupied by the rebound member 44. Specifically, the portion occupied by the ball 42 is a portion of the ball 42 located in the ink flow hole 62. The portion occupied by the rebound member 44 is a portion of the lever portion 48 of the rebound member 44 located between the start point S1 and the end point S2 of the space portion SA. More specifically, the portion occupied by the rebound member 44 is a portion between the front end of the lever portion 48 and the end point S2. The space SA is defined by the above conditions, and the volume of the space SA can be calculated.

In the present embodiment, the volume of the space portion SA may be 0.02mm ³ The above. Preferably, the volume of the space portion SA may be 0.02mm ³ Above 0.08mm ³ The following is given. Further preferably, the volume of the space portion SA may be 0.25mm ³ Above 0.05mm ³ The following is given.

The present inventors have found that drying of the ink in the ball holding chamber 52 can be suppressed by sufficiently determining the amount of the ink stored in the region behind the ball 42 and close to the ball 42. Further, it has been found through further investigation that, particularly when the front end 64a of the ink flow channel 64 is set as a start point and the position 0.3mm rearward from the front end 62a of the ink flow channel 62 is set as an end point, the volume of the ink flow channel 62 and the space portion SA of the ink flow channel 64 in the region from the start point to the end point greatly affects the drying property of the ink in the ball holding chamber 52. As can be seen from this, the drying property of the ink in the ball holding chamber 52 can be controlled based on the volume of the space portion SA, regardless of the shapes or the sizes of the ink flow holes 62 and the ink flow grooves 64. This is considered because, even when writing is not performed, a minute gap is generated between the tip end portion (caulking portion 56) of the pen tip and the ball 42 due to the dent, the fiber, or the like, and the ink in the ball holding chamber 52 is easily dried, but when the volume of the space portion SA is sufficiently ensured, the ink is wetted by a sufficient amount of ink in the space portion SA located behind the ball holding chamber 52, and drying of the ink in the ball holding chamber 52 can be suppressed. The inventors have further studied the numerical range of the volume of the space portion SA, and have determined the above range as an appropriate numerical range. The technical idea of controlling the dryness of the ink in the ball holding chamber 52 based on the volume of the space portion SA is not known in the past, and it can be said that the present invention has a great technical contribution to the prior art.

In the present embodiment, the space (the 2 nd space SB) between the ink flow hole 62 and the ink flow groove 64 is defined by the following condition from the start point S1 to a position 60% of the length of the diameter of the ball 42 rearward in the axial direction da from the front end 62a of the ink flow hole 62. The ball 42 is positioned rearmost in the ball holding chamber 52 and is in contact with the tip 62a of the ink flow hole 62. In this case, a part of the ball 42 is located in the ink flow hole 62. The space within the ball holding chamber 52 is not included in the space portion SB. Even if located within the length L4, the portion not filled with ink is not included in the space portion SB. The portions not filled with the ink are, for example, the portion occupied by the ball 42 and the portion occupied by the rebound member 44. Specifically, the portion occupied by the ball 42 refers to a portion of the ball 42 located in the ink flow hole 62. The portion occupied by the rebound member 44 is a portion of the stem portion 48 of the rebound member 44 located between the start point S1 and a position 60% of the length of the diameter of the ball 42 rearward in the axial direction da from the front end 62a of the ink flow hole 62. More specifically, the portion occupied by the rebound member 44 is a portion between the front end of the lever portion 48 and a position that is 60% of the diameter of the ball 42 rearward in the axial direction da from the front end 62a of the ink flow hole 62. The space SB is defined under the above conditions, and the volume of the space SB can be calculated.

The inventors have found that the volume of the ink flow hole 62 and the space SB of the ink flow groove 64 in the region between the front end 64a of the ink flow groove 64 and the position at which the front end 62a of the ink flow hole 62 is 60% of the diameter of the ball 42 rearward has a great influence on the drying property of the ink in the ball holding chamber 52, as in the volume of the space SA. As can be seen from this, the drying property of the ink in the ball holding chamber 52 can be controlled based on the volume of the space SB, regardless of the shapes or the sizes of the ink flow holes 62 and the ink flow grooves 64. Specifically, a space SC from the tip 50a of the pen tip body 50 to the starting point S1 in the ball holding chamber 52 is defined, and when the ratio of the volume of the space SB to the volume of the space SC is within a certain range, it is known that the drying property of the ink in the ball holding chamber 52 can be controlled.

The space (3 rd space) SC from the front end 50a of the pen tip body 50 to the start point S1 in the ball holding chamber 52 is defined by the following condition. The ball 42 is positioned rearmost in the ball holding chamber 52 and is in contact with the tip 62a of the ink flow hole 62. Even if located between the front end 50a and the start point S1, the portion not filled with ink is not included in the space portion SC. Specifically, the portion not filled with ink is a portion occupied by the ball 42. The volume of the space SC can be calculated by defining the space SC under the above conditions.

The volume of the space SB may be 1.6 times or more the volume of the space SC. This can sufficiently secure the volume of the space SB, and thus can further suppress drying of the ink in the space SC of the ball holding chamber 52. Preferably, the volume of the space SB may be 1.6 times or more and 5 times or less the volume of the space SC. Further, the volume of the space SB may be 1.7 times or more the volume of the space SC. More preferably, the volume of the space SB may be 1.7 times or more and 3 times or less the volume of the space SC.

The volume of the space portion SA may be 1.5 times or more the volume of the space portion SC. This can sufficiently secure the volume of the space portion SA, and thus can further suppress drying of the ink in the space portion SC of the ball holding chamber 52. Preferably, the volume of the space portion SA may be 1.5 times or more and 5 times or less the volume of the space portion SC. Further, the volume of the space portion SA may be 1.7 times or more the volume of the space portion SC. More preferably, the volume of the space portion SA may be 1.7 to 3 times the volume of the space portion SC.

The ballpoint pen tip 40 of the present embodiment includes a ball 42 having a diameter of 0.5mm or less and a tip body 50 holding the ball 42, the tip body 50 includes a ball holding chamber 52 holding the ball 42, a rear hole 57 located behind the ball holding chamber 52, an ink flow through hole 62 communicating the ball holding chamber 52 with the rear hole 57, and an ink flow through groove 64 extending in a radial dr from the ink flow through hole 62 and opening in the ball holding chamber 52 and not reaching the rear hole 57, when the ink consumption per 100m writing is A (mg) and the diameter of the ball 42 is B (mm), a ratio (A/B) of the ink consumption A to the diameter B of the ball 42 is 200mg/mm or more and 800mg/mm or less, and when a position from the front end 62a of the ink flow through groove 64 to the rear 0.3mm is S2, a volume SA of the ink flow through hole 62 from the front end 64a of the ink flow through groove 64 is 200mg/mm or more and SA 02mm is a space in the ink flow through groove 64 when the position from the front end 62a of the ink flow through hole 62 to the rear end 0.3mm is S2 is the end 2 ³ The above.

The ball-point pen refill 30 of the present embodiment includes the ball-point pen tip 40 and the ink containing tube 32 containing ink.

The ball-point pen 10 of the present embodiment includes the ball-point pen refill 30 described above.

According to the ballpoint pen tip 40, the ballpoint pen refill 30, and the ballpoint pen 10, the volume of the space SA between the ink flow hole 62 and the ink flow groove 64 in the region near the ball 42 can be increased by sufficiently securing the region near the ball 42, particularly, the volume of the space SA between the ink flow hole 62 and the ink flow groove 64 in the region from the start point S1 to the end point S2 when the start point S1 is the front end 64a of the ink flow groove 64 and the end point S2 is the position 0.3mm rearward from the front end 62a of the ink flow hole 62. This effectively suppresses drying of the ink in the ball holding chamber 52. In particular, even when left alone for a long period of time without using the ballpoint pen 10, drying of the ink in the ball holding chamber 52 can be effectively suppressed.

In the ballpoint pen tip 40 of the present embodiment, the volume of the space SA in the ink flow hole 62 and the ink flow groove 64 from the start point S1 to the end point S2 is 1.5 times or more the volume of the space SC from the tip 50a of the pen tip body 50 to the start point S1 in the ball holding chamber 52.

According to the ball-point pen tip 40, the volume of the space portion SA can be sufficiently ensured, and thus drying of ink in the space portion SC of the ball holding chamber 52 can be further suppressed.

In the ballpoint pen tip 40 of the present embodiment, the inner diameter D1 of the ink flow hole 62 is 40% or more of the diameter of the ball 42.

According to the ballpoint pen tip 40, the cross-sectional area of the ink flow hole 62 can be sufficiently ensured, and therefore the amount of ink existing in the region near the ball 42 can be further increased.

In the ballpoint pen tip 40 of the present embodiment, the length L1 of the ink flow hole 62 is 90% or less of the diameter of the ball 42.

According to the ballpoint pen tip 40, the length in the axial direction da of the ink flow hole 62 having a relatively small cross-sectional area among the flow paths of the ink from the rear hole 57 to the ball holding chamber 52 can be reduced, and therefore the resistance to the flow of the ink in the ink flow hole 62 becomes small. Therefore, the flow rate of the ink from the rear hole 57 to the ball holding chamber 52 can be increased, and the amount of the ink stored in the area near the ball 42 can be sufficiently ensured.

In the ballpoint pen tip 40 of the present embodiment, the length L2 of the region of the ink flow hole 62 where the ink flow groove 64 is not formed is 90% or less of the diameter of the ball 42.

The region of the ink flow hole 62 where the ink flow groove 64 is not formed is a region of the smallest cross-sectional area in the flow path of the ink from the rear hole 57 toward the ball holding chamber 52. According to the ballpoint pen tip 40 of the present embodiment, since the length of the region of the smallest cross-sectional area in the axial direction da can be reduced, the resistance of the ink in the flow path becomes small. Therefore, the flow rate of the ink from the rear hole 57 to the ball holding chamber 52 can be further increased, and the amount of the ink stored in the area near the ball 42 can be sufficiently ensured.

The ballpoint pen tip 40 of the present embodiment further includes a rebound member 44, and the rebound member 44 includes a spring portion 46 and a rod portion 48 extending forward from the spring portion 46 and abutting against the ball 42 from the rear.

According to the ballpoint pen tip 40, when not writing, the ball 42 is positioned at the forefront in the ball holding chamber 52 by the urging force of the rebound member 44, and abuts against the caulking portion 56 of the tip body 50. At this time, the gap between the ball 42 and the caulking portion 56 is sealed. This suppresses the outflow of ink during non-writing and also suppresses the drying of ink in the ball holding chamber 52.

In the ballpoint pen tip 40 of the present embodiment, the movable range C of the ball 42 with respect to the tip body 50 in the front-rear direction is 0.015mm or more and 0.06mm or less.

When the ball 42 has such a movable range C, a gap that can be generated between the ball 42 and the caulking portion 56 becomes relatively large, and the ink in the ball holding chamber 52 is easily dried. Therefore, in such a ballpoint pen tip 40, the volume of the space portion SA is set to 0.02mm ³ The effect of suppressing the drying of the ink in the ball holding chamber 52 is greatly exhibited.

Examples

Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited to the examples.

5 samples of the pen points of the ball-point pens of sample numbers 1 to 5 were prepared, and each sample was subjected to a writing property test after being left for a predetermined period of time, and the quality of handwriting was evaluated.

Size and material of sample

In all samples, the following conditions were common.

Diameter of the ball: 0.5 (mm)

Mo Yeliu number of through slots: 4

Distance R2 from the central axis to the main portion of the peripheral wall of the ink flow channel: 0.245 (mm)

Width W of ink flow channel: 0.09 (mm)

Length of main part of peripheral wall of Mo Yeliu through slot: 0.13 (mm)

Ball material: tungsten carbide

Material of pen tip body: stainless steel material

Material of the rebound member: stainless steel material

Composition of ink composition

25 parts by weight of a thermochromic microcapsule pigment (which is previously cooled to-20 ℃ or lower to develop a black color), 0.3 part by weight of a shear-thinning viscosity-imparting agent (xanthan gum), 10 parts by weight of urea, 10 parts by weight of glycerin, and a nonionic permeability-imparting agent [ SAN NOPCO corporation, product name: NOPCO SWWET-366]0.5 part by weight of a modified silicone defoamer [ SAN NOPCO Co., ltd., product name: NOPCO 8034]0.1 part by weight of a phosphate-based surfactant [ product name, manufactured by first Industrial pharmaceutical Co., ltd.: plysurf AL]0.5 part by weight of a pH regulator (triethanolamine) 0.5 part by weight of a mildew preventive [ manufactured by Lonza Japan Co., ltd., product name: PROXEL XL-2]0.2 part by weight, and 52.9 parts by weight of water. The pH of the resulting ink composition was 8.0 at 20℃and the viscosity measured at 20℃was 3.84sec at a shear rate ^-1 780 mPas at a shear rate of 384sec ^-1 The following is 35.0 mPas.

The ballpoint pen nibs of samples 1 to 5 shown in table 1 were attached to one end of an ink containing tube made of polypropylene via a nib holder, and the ink composition was filled into the ink containing tube, and further, an ink reverse flow preventing fluid was filled in close contact with the rear end surface of the ink, to obtain a ballpoint pen refill. The ink consumption per 100m writing of this ballpoint pen refill was 140mg.

Evaluation method

After each sample was allowed to stand in a constant temperature bath set at a temperature of 50℃and a humidity of 0% for 60 days, the pen tip was brought into contact with the paper surface, and the pen tip was continuously moved to draw a circle having a diameter of 10mm, whereby handwriting was formed. In this case, the fly-white of the handwriting may be generated in several circles starting from the beginning of the handwriting. In this embodiment, the number of circles for generating the handwriting fly-white is used, and the obtained handwriting is evaluated according to the following evaluation criterion.

A: the number of circles generating fly-white is 6 or less

B: the number of circles generating fly-white is 7 or more

In the case of evaluation a, since the number of circles that generate the fly-white is relatively small, it can be said that drying of the ink in the ball holding chamber is sufficiently suppressed. On the other hand, in the case of evaluation B, since the number of circles generating the fly-white is relatively large, it cannot be said that drying of the ink in the ball holding chamber is sufficiently suppressed. In particular, the evaluation B herein is considered to be a practically unusable level.

In table 1, D1 is an inner diameter (mm) of the ink flow hole. D2 is the diameter (mm) of the stem of the rebound member. L1 is the length (mm) of the ink flow hole, and L5 is the length (mm) in the axial direction da from the front end (64 a) of the ink flow channel to the front end (62 a) of the ink flow hole. L6 is the length of the inclined portion of the peripheral wall of the ink flow channel in the axial direction da, i.e., the length (mm) in the axial direction da from the rear end (67 a) of the main portion to the rear end (64 b) of the inclined portion. V1 is the volume (mm) of the 1 st space portion (SA) ³ ). V2 is the volume (mm) of the 2 nd Space (SB) ³ ). V3 is the volume (mm) of the 3 rd Space (SC) ³ ). V1/V3 is the volume V1 (mm) ³ ) And volume V3 (mm) ³ ) Ratio of the two components. V2/V3 is the volume V2 (mm) ³ ) And volume V3 (mm) ³ ) Ratio of the two components. In samples 1 to 5 having a ball diameter of 0.5 (mm), the length of 60% of the ball diameter was 0.3 (mm), and the value of V1 was the same as the value of V2. Meanwhile, in samples 1 to 5, the value of V1/V3 was the same as the value of V2/V3.

TABLE 1

Fig. 5 is a graph showing calculation results of volumes of the ink flow holes and the space portions (SA) in the ink flow grooves in each sample. In the graph of fig. 5, the horizontal axis represents the distance (mm) from the tip (62 a) of the ink flow hole, and more specifically, the distance measured rearward in the axial direction da when the tip of the ink flow hole is 0 mm. The portion with negative distance on the horizontal axis is shown to be located at a higher positionThe front end of the ink flow hole is located further forward. The vertical axis is the cumulative volume (mm) of the space portion (SA) at each position along the axial direction da ³ ). The accumulation volume is calculated from the front end (64 a) of the ink flow channel. That is, at the front end of the ink flow channel, the cumulative volume is 0mm ³ . Here, the tip of the ink flow channel is located further forward than the tip of the ink flow hole (see fig. 3). Thus, the cumulative volume is 0mm ³ The distance of the horizontal axis of the point of (2) is negative. In addition, at the front end of the ink flow through hole with the distance of 0mm on the transverse axis, the accumulated volume is larger than 0mm ³ 。

As shown in table 1 and fig. 5, in samples 1 and 2, the cumulative volume was 0.2mm at the point where the distance of the horizontal axis, i.e., the distance from the front end of the ink flow hole was 0.3mm ³ The above. On the other hand, in samples 3 to 5, the cumulative volume was less than 0.2mm at the point where the distance of the transverse axis was 0.3mm ³ . The cumulative volume at the point at a distance of 0.3mm from the tip of the ink flow hole corresponds to the volume of the space portion (SA). In samples 2 and 5 in which the length L1 of the ink flow through hole was 0.3mm, since the volume of the rear hole was accumulated in the region where the distance of the lateral axis exceeded 0.3mm, the accumulated volume was drastically increased, bounded by the point of 0.3 mm.

In Table 1, the volume V1 was 0.02mm ³ Samples 1 and 2 above were evaluated as a. That is, it is found that the volume V1 of the space portion SA is set to 0.02mm ³ As described above, drying of the ink in the ball holding chamber 52 is effectively suppressed. This is considered to be because the volume V1 of the space SA is set to 0.02mm ³ As described above, the amount of ink existing in the region near the ball 42 can be sufficiently ensured. Samples 1 and 2 having a V1/V3 value of 1.5 times or more were evaluated as A. That is, it is known that by setting the value of V1/V3 to 1.5 times or more, drying of the ink in the ball holding chamber 52 is effectively suppressed. Samples 1 and 2 having a V2/V3 value of 1.6 times or more were evaluated as A. That is, it is known that by setting the value of V2/V3 to 1.6 times or more, drying of the ink in the ball holding chamber 52 is effectively suppressed.

Embodiment 2

Embodiment 2 will be described with reference to fig. 6 to 9. In the following description, overlapping descriptions will be omitted for the portions that can be configured similarly to embodiment 1. In the drawings used in the following description, the same reference numerals as those used for the corresponding parts in embodiment 1 are used for parts that can be configured similarly to embodiment 1.

In order to increase the density of writing formed by a ballpoint pen, increasing the amount of ink per unit length of writing has been studied. However, in the conventional ball point pen, the amount of ink for forming handwriting cannot be sufficiently increased. As a result of intensive studies on measures for improving this problem, the inventors have found that by improving the flow of ink from the rear holes to the ink flow grooves, the amount of ink supplied from the rear holes to the beads can be increased, and thus the amount of ink forming handwriting can be increased.

The present embodiment has been made in consideration of this point, and an object thereof is to improve the flow of ink from the rear hole to the ink flow channel in the ballpoint pen tip.

The ball-point pen tip of this embodiment comprises a ball and a tip body for holding the ball,

the pen tip body includes:

a ball holding chamber for holding the ball;

a rear hole located at the rear of the ball holding chamber;

an ink flow groove extending radially from the ink flow hole, opening the ball holding chamber, and reaching the rear hole,

the ratio (R1/R2) of the distance R1 from the center axis of the pen tip body to the peripheral wall of the ink flow hole to the distance R2 from the center axis to the peripheral wall of the rear hole is 0.9 or more.

In the ball-point pen tip of the present embodiment,

the ratio (C1/C2) of the total C1 of the circumferences of the portions of the peripheral wall of the ink flow hole where the ink flow grooves are formed to the total C2 of the circumferences of the portions of the peripheral wall of the ink flow hole where the ink flow grooves are not formed may be 0.5 or more.

In the ball-point pen tip of the present embodiment,

The movable range of the ball with respect to the pen tip main body in the front-rear direction may be 0.015mm or more and 0.05mm or less.

The ball-point pen refill of the present embodiment comprises:

the above-mentioned ball-point pen nib; and

an ink containing cylinder containing ink.

In the ball-point pen refill of the present embodiment,

the ink may be a thermochromic ink.

The ball-point pen of this embodiment is provided with the ball-point pen refill described above.

According to the present embodiment, the flow of ink from the rear hole to the ink flow channel in the ballpoint pen tip can be improved.

Fig. 6 is a view for explaining the present embodiment, and is a sectional view showing an example of the ballpoint pen 10, fig. 7 is a longitudinal sectional view showing the ballpoint pen tip 40 in an enlarged manner, and fig. 8 is a longitudinal sectional view showing the vicinity of the tip end of the ballpoint pen tip 40 in a further enlarged manner.

In the present embodiment, ink that can be used for a ballpoint pen can be used as ink contained in the ballpoint pen refill 30 without particular limitation. As an example, a thermochromic ink may be used as the ink. The thermochromic ink may be a reversible thermochromic ink. As an example of the reversible thermochromic ink, a reversible thermochromic ink that changes from a color development state to a color development state by heating and changes from a color development state to a color development state by cooling may be used.

In addition, in the aqueous gel ink having shear thinning properties, the coloring material is not particularly limited, and dyes, pigments, metallic luster pigments, fluorescent pigments, titanium oxide, thermochromic pigments, and the like can be used. In particular, a thermochromic pigment is particularly preferably used in the present embodiment, which can improve the flow of ink and increase the density of handwriting, because it is difficult to obtain the handwriting density due to the lack of its own coloring power.

Next, the ballpoint pen tip 40 of the present embodiment will be described. The ball-point pen nib 40 includes a ball 42 and a nib body 50 holding the ball 42. The pen tip body 50 is formed of a metal material such as stainless steel. In view of corrosion resistance, the pen tip body 50 is preferably formed of stainless steel.

The pen tip body 50 is manufactured by cutting, for example. At this time, if burrs or the like generated by cutting during production remain on the inner surface of the pen tip body 50, the burrs may obstruct the flow of ink in the pen tip body 50. In order to solve this problem, it is conceivable to clean the inner surface of the pen tip body 50 after manufacturing the pen tip body 50 by cutting. By this cleaning, burrs are removed, and the surface roughness (arithmetic average roughness Ra) of the inner surface of the nib body 50 is reduced, and the inner surface is mirrored. However, as a result of the study by the present inventors, even when the inner surface of the pen tip main body 50 is cleaned, there is a case where the flow of ink in the pen tip main body 50 cannot be significantly improved. This is presumably because, in the case of using an aqueous ink such as an aqueous ink or an aqueous shear thinning ink as the ink, in stainless steel, the contact angle of the ink on the surface becomes large and the ink diffusion is suppressed, and the ink easily flows in the surface having a surface roughness larger than that of a mirror surface having a surface roughness such as an arithmetic average roughness Ra of less than 10 nm. Therefore, the surface roughness of the inner surface of the pen tip main body 50 is set in JIS B0601: the arithmetic average roughness Ra meter specified in 2013 is preferably 10nm to 500nm, more preferably 50nm to 300nm, still more preferably 100nm to 150 nm.

The pen tip body 50 has a ball holding chamber 52, a rear hole 57, an ink flow through hole 62, and an ink flow through groove 64.

The ink flow through hole 62 is located between the ball holding chamber 52 and the rear hole 57, and communicates the ball holding chamber 52 with the rear hole 57. The ink flow through hole 62 extends in a straight line in the axial direction da. In the illustrated example, the ink flow hole 62 is a through hole having a cylindrical shape, and has a peripheral wall 63 having a cylindrical shape. The ink flow hole 62 functions as a flow path of ink from the rear hole 57 toward the ball holding chamber 52. The inner diameter (diameter) D1 of the ink flow hole 62 may be, for example, 40% to 90% of the diameter of the ball 42. Preferably, the inner diameter D1 may be 50% to 80% of the diameter of the ball 42. The inner diameter D1 may be, for example, 0.2mm to 0.45 mm. Preferably, the inner diameter D1 is not less than 0.25mm and not more than 0.4 mm. The center axis of the ink flow hole 62 coincides with the center axis a of the pen tip main body 50.

The length L1 of the ink flow hole 62 may be, for example, 0% or less than 90% of the diameter of the ball 42. Preferably, the length L1 may be 40% to 80% of the diameter of the ball 42. The length L1 may be, for example, more than 0mm and 0.45mm or less. Preferably, the length L1 may be 0.2mm or more and 0.4mm or less. Here, the length L1 of the ink flow hole 62 is a length in the axial direction da from the front end 62a of the ink flow hole 62 to the rear end 62b of the ink flow hole 62. In the illustrated example, the front end 62a of the ink flow hole 62 is the forefront portion of the portions having the inner diameter D1, and the rear end 62b of the ink flow hole 62 is the rearmost portion of the portions having the inner diameter D1. When the ball 42 is positioned rearmost in the ball holding chamber 52, the tip 62a of the ink flow hole 62 abuts against the ball 42. If the ink flow hole 62 has such a size D1 and/or L1, the flow amount of the ink through the ink flow hole 62 can be appropriately ensured.

The ink circulation groove 64 extends from the peripheral wall 63 of the ink circulation hole 62 in the radial direction dr and opens into the ball holding chamber 52. The ink flow channel 64 reaches the ball holding chamber 52 and reaches the rear hole 57. Accordingly, the ink circulation groove 64 communicates with the ball holding chamber 52 and the rear hole 57. In the present embodiment, the ink flow channel 64 extends linearly in a direction parallel to the axial direction da. The front end 64a of the ink flow channel 64 is located at the rear wall 54 of the ball holding chamber 52. The rear end 64b of the ink flow channel 64 is located on the inclined surface 158, and the inclined surface 158 is disposed in front of the forefront hole 57a1 of the rear hole 57. By providing the pen tip body 50 with such an ink flow channel 64, even when the ball 42 is positioned rearmost in the ball holding chamber 52 and abuts against the front end 62a of the ink flow channel 62 (see fig. 8), a gap is formed between the ball 42 and the front end 64a of the ink flow channel 64, and ink can flow from the rear hole 57 and the ink flow channel 62 to the ball holding chamber 52 via the ink flow channel 64.

The ink flow channel 64 has a peripheral wall 66 facing the ink flow channel 62. The peripheral wall 66 is a wall that defines the outer contour of the ink flow channel 64 in the radial direction dr. The peripheral wall 66 extends in both the axial direction da and the circumferential direction dc. The distance R1 from the central axis a of the pen tip body 50 to the peripheral wall 66 of the ink flow channel 64 may be, for example, 0.2mm to 1 mm. Preferably, the distance R1 may be 0.3mm or more and 0.7mm or less.

The width W (see fig. 9) of the ink flow channel 64 in the direction perpendicular to both the axial direction da and the radial direction dr may be, for example, 0.01mm to 0.15 mm. Preferably, the width W may be 0.05mm or more and 0.1mm or less.

The pen tip body 50 has 1 ink circulation groove 64 or a plurality of ink circulation grooves 64. In the case where the pen tip body 50 has a plurality of ink flow grooves 64, the ink flow grooves 64 may be arranged to have equal angular intervals from each other in the circumferential direction dc. In the example shown in fig. 9, the pen tip body 50 has 4 ink circulation grooves 64 arranged at equal angular intervals in the circumferential direction dc.

The rear hole 57 is located rearward of the ball holding chamber 52, and extends in the axial direction da. The rear hole 57 communicates with the ink containing cylinder 32 via the pen tip holder 34, and functions as a flow path of ink from the ink containing cylinder 32 toward the ball holding chamber 52. The rear hole 57 is formed by a hole portion formed forward from the rear end of the pen tip main body 50. The rear hole 57 includes a hole portion formed in a cylindrical shape. The central axis of the rear hole 57 coincides with the central axis a of the nib body 50.

In the present embodiment, the rear hole 57 includes a plurality of cylindrical hole portions 57a having different diameters. In particular, the diameter of each hole portion 57a constituting the rear hole 57 increases rearward. The center axis of each hole 57a coincides with the center axis a of the pen tip body 50. When the rear hole 57 includes a plurality of hole portions 57a having different diameters, the hole portion located at the forefront among the plurality of hole portions 57a is referred to as the forefront hole 57a1. In the case where the rear hole 57 includes only 1 hole portion 57a, the hole portion 57a is defined as the forefront hole 57a1. The ink flow hole 62 and the forefront hole 57a1 are connected to each other by an inclined surface 158, and the diameter of the inclined surface 158 increases as it goes rearward. The 2 hole portions 57a adjacent to the axial direction da are also connected to each other by the inclined surface 158, and the diameter of the inclined surface 158 increases as it goes rearward. The inclined surface 158 is formed as a side surface of a truncated cone having a central axis aligned with the central axis a of the pen tip body 50. In the cross section including the central axis a, the inclination angle θ of the inclined surface 158 with respect to the central axis a may be, for example, 30 degrees to 60 degrees, preferably 40 degrees to 50 degrees.

In the present embodiment, the diameter D2 of the forefront hole 57a1 is smallest among the diameters of the hole portions 57a constituting the rear hole 57. The diameter D2 may be, for example, 0.3mm to 1 mm. Preferably, the diameter D2 may be 0.4mm or more and 0.8mm or less. The distance R2 from the central axis a of the pen tip main body 50 to the peripheral wall 159 of the forefront hole 57a1 coincides with the radius of the forefront hole 57a1, i.e., 1/2 of the diameter D2.

As described above, the conventional ball point pen cannot sufficiently increase the amount of ink for forming handwriting, and cannot increase the density of handwriting formed by the ball point pen. As a result of intensive studies on measures for improving this problem, the inventors have found that by improving the flow of ink from the rear holes 57 to the ink flow grooves 64, the amount of ink supplied from the rear holes 57 to the beads 42 can be increased, and thus the amount of ink forming handwriting can be increased. Specifically, by setting the ratio (R1/R2) of the distance R1 from the central axis a of the pen tip main body 50 to the peripheral wall 66 of the ink flow channel 64 to the distance R2 from the central axis a to the peripheral wall 159 of the forefront hole 57a1 to 0.9 or more, the flow of ink from the rear hole 57 to the ink flow channel 64 can be improved.

The inventors speculate that this reason is based on the following mechanism. When R1/R2 is smaller than 0.9, the height difference formed between the peripheral wall 66 of the ink circulation groove 64 and the peripheral wall 159 of the foremost hole 57a1 becomes large. In particular, the height difference becomes larger in the radial direction dr. This level difference may prevent the ink from flowing in the axial direction da. Specifically, the ink flowing from the foremost hole 57a1 to the ink flow groove 64 collides with the height difference formed between the peripheral wall 66 and the peripheral wall 159, thereby blocking the flow of the ink. On the other hand, in the case where R1/R2 is 0.9 or more as in the present embodiment, the height difference formed between the peripheral wall 66 of the ink circulation groove 64 and the peripheral wall 159 of the forefront hole 57a1 becomes small. That is, the height difference becomes smaller in the radial direction dr. Therefore, it is possible to effectively suppress the flow of the ink flowing from the foremost hole 57a1 to the ink flow groove 64 from being hindered by the level difference formed between the peripheral wall 66 and the peripheral wall 159.

Preferably, R1/R2 may be 0.95 or more. In addition, R1/R2 may preferably be less than 1.0. When R1/R2 is such a value, it is possible to more effectively suppress the flow of ink flowing from the foremost hole 57a1 to the ink flow groove 64 from being hindered by the level difference formed between the peripheral wall 66 and the peripheral wall 159.

In the present embodiment, the diameter D3 of the ball holding chamber 52 may be, for example, 100% to 120% of the diameter of the ball 42. Preferably, the diameter D3 may be more than 100% and 120% or less of the diameter of the ball 42. More preferably, the diameter D3 may be 105% to 110% of the diameter of the ball 42. The diameter D3 may be, for example, 0.15mm to 0.6 mm. Preferably, the diameter D3 may be 0.15mm or more and 0.4mm or less. The distance R3 from the center axis A of the pen tip main body 50 to the peripheral wall of the ball holding chamber 52 coincides with the radius of the ball holding chamber 52, i.e., 1/2 of the diameter D3.

As described above, in addition to the ratio (R1/R2) of the distance R1 to the distance R2 being 0.9 or more, the flow of ink from the rear hole 57 to the ink flow channel 64 and further to the ball holding chamber 52 can be improved by setting the ratio (R1/R3) of the distance R1 to the distance R3 to be 0.9 or more.

Fig. 9 is a cross-sectional view corresponding to the line IX-IX of fig. 8, in particular, a view showing the ballpoint pen tip 40 in a section orthogonal to the central axis a of the pen tip body 50.

As described above, the peripheral wall 63 of the ink flow hole 62 has a cylindrical shape. Therefore, in the cross section shown in fig. 9, the peripheral wall 63 has a circular shape. In this specification, the length in the circumferential direction dc is referred to as the circumference. In the illustrated example, the perimeter of the portion of the peripheral wall 63 of the ink flow hole 62 where 1 ink flow channel 64 is formed is C11. The circumferential length C11 is a length in the circumferential direction dc assuming that the curvature of the circumferential wall 63 is maintained and extended at the portion where the ink circulation groove 64 is formed. In the illustrated example, 4 ink circulation grooves 64 having the same size are arranged at equal angular intervals in the circumferential direction dc. In this case, the total of the circumferences C1 of the portions of the peripheral wall 63 of the ink flow hole 62 where the ink flow grooves 64 are formed is 4 times C11. In addition, the circumferential length of the circumferential wall 63 between 2 ink flow grooves 64 adjacent in the circumferential direction dc is set to C21. In this case, the total C2 of the circumferences of the portions of the peripheral wall 63 of the ink flow hole 62 where the ink flow channel 64 is not formed is 4 times C21.

In this embodiment, the ratio of C1 to C2 (C1/C2) is 0.5 or more. This can increase the cross-sectional area of the ink flow channel 64. Therefore, the flow rate of the ink from the rear hole 57 toward the ball holding chamber 52 can be sufficiently ensured. The ratio C1/C2 may be 10 or less.

The ballpoint pen tip 40 of the present embodiment includes the ball 42 and the tip body 50 holding the ball 42, the tip body 50 includes the ball holding chamber 52 holding the ball 42, the rear hole 57 located at the rear of the ball holding chamber 52, the ink flow hole 62 communicating the ball holding chamber 52 with the rear hole 57, and the ink flow channel 64 extending from the ink flow hole 62 in the radial direction dr and opening into the ball holding chamber 52 and reaching the rear hole 57, the rear hole 57 includes the forefront hole 57a1 located at the forefront, and the ratio (R1/R2) of the distance R1 from the central axis a of the tip body 50 to the peripheral wall 66 of the ink flow channel 64 to the distance R2 from the central axis a to the peripheral wall 159 of the forefront hole 57a1 is 0.9 or more.

According to the ballpoint pen tip 40, the ballpoint pen refill 30, and the ballpoint pen 10, since the height difference formed between the peripheral wall 66 of the ink flow passage 64 and the peripheral wall 159 of the rear hole 57 becomes small, it is possible to effectively suppress the flow of ink flowing from the rear hole 57 to the ink flow passage 64 from being hindered by the height difference formed between the peripheral wall 66 and the peripheral wall 159. Therefore, the flow of ink from the rear hole 57 to the ink flow channel 64 in the ballpoint pen tip 40 can be improved.

In addition, when a conventional ball point pen is left for a long period of time without writing, ink may be dried and cured in the ball holding chamber. In this case, there is a problem that ink is not properly supplied to the ball, the handwriting is off-white, or writing is not possible at all. According to the ballpoint pen tip 40, the ballpoint pen refill 30, and the ballpoint pen 10 of the present embodiment, by improving the flow of ink from the rear hole 57 to the ink flow channel 64 in the ballpoint pen tip 40, the flow rate of ink from the rear hole 57 to the ball holding chamber 52 can be increased. This effectively suppresses drying of the ink in the ball holding chamber 52.

In the ballpoint pen tip 40 of the present embodiment, the ratio (C1/C2) of the total C1 of the circumferences of the portions of the peripheral wall 63 of the ink flow hole 62 where the ink flow grooves 64 are formed to the total C2 of the circumferences of the portions of the peripheral wall 63 of the ink flow hole 62 where the ink flow grooves 64 are not formed is 0.5 or more.

According to the ballpoint pen tip 40, the cross-sectional area of the ink flow channel 64 can be increased, and therefore, the flow rate of ink from the rear hole 57 to the ball holding chamber 52 can be sufficiently ensured. Therefore, the flow of ink from the rear hole 57 to the ink flow channel 64 in the ballpoint pen tip 40 can be further improved.

In the ballpoint pen tip 40 of the present embodiment, the movable range C of the ball 42 with respect to the tip body 50 in the front-rear direction is 0.015mm to 0.06 mm.

When the ball 42 has such a movable range C, a gap that can be generated between the ball 42 and the caulking portion 56 becomes relatively large, and the ink in the ball holding chamber 52 is easily dried. Therefore, in such a ballpoint pen tip 40, the effect of suppressing the drying of the ink in the ball holding chamber 52 by improving the flow of the ink from the rear hole 57 to the ink flow channel 64 is greatly exerted.

As described above, the surface roughness of the inner surface of the pen tip body 50 is set in JIS B0601: the arithmetic average roughness Ra meter specified in 2013 is preferably 10nm to 500 nm. In particular, the surface roughness of the surface connected to the ink flow channel 64 is determined in accordance with JIS B0601: the arithmetic average roughness Ra meter specified in 2013 is preferably 10nm to 500nm, more preferably 50nm to 300nm, still more preferably 100nm to 150 nm. This improves the flow of ink into the ink flow channel 64. The surface connected to the ink flow channel 64 is at least 1 of the inner surface constituting the ink flow channel 62 and the inner surface constituting the rear hole 57.

The following describes preferred embodiments of the present embodiment.

[ additional note 1]

A ball point pen nib comprising a ball and a nib body holding the ball, wherein,

the pen tip body includes:

a ball holding chamber for holding the ball;

a rear hole located at the rear of the ball holding chamber;

the rear aperture includes a forward-most aperture located forward-most,

the ratio (R1/R2) of the distance R1 from the central axis of the pen tip body to the peripheral wall of the Mo Yeliu through groove to the distance R2 from the central axis to the peripheral wall of the forefront hole is 0.9 or more.

[ additionally noted 2]

The ballpoint pen tip according to supplementary note 1, wherein a ratio (C1/C2) of a total C1 of circumferences of the portions of the peripheral wall of the ink flow hole where the ink flow grooves are formed to a total C2 of circumferences of the portions of the peripheral wall of the ink flow hole where the ink flow grooves are not formed is 0.5 or more.

[ additionally recorded 3]

The ballpoint pen tip according to any one of supplementary notes 1 and 2, wherein a movable range of the ball with respect to the tip body in a front-rear direction is 0.015mm or more and 0.05mm or less.

[ additional note 4]

A ball-point pen refill is provided with:

the ballpoint pen tip according to any one of supplementary notes 1 to 3; and

an ink containing cylinder containing ink.

[ additional note 5]

The ball-point pen refill according to supplementary note 4, wherein the ink is a thermochromic ink.

[ additional note 6]

A ball-point pen comprising the ball-point pen refill according to any one of supplementary notes 4 and 5.

Claims

1. A ball-point pen nib comprising a ball having a diameter of 0.5mm or less and a nib body holding the ball, wherein,

the pen tip body has:

a ball holding chamber holding the ball;

a rear aperture located behind the ball-holding chamber;

an ink flow through hole that communicates the ball holding chamber with the rear hole; and

an ink flow channel extending radially from the ink flow channel, opening in the ball holding chamber, and not reaching the rear hole,

when the ink consumption per 100m of writing is A, A in mg and the diameter of the beads is B, B in mm, the ratio of the ink consumption A to the diameter B of the beads, A/B, is 200mg/mm to 800mg/mm,

2. The ballpoint pen nib according to claim 1, wherein the volume of the space in the ink flow hole and the ink flow groove from the start point to the end point is 1.5 times or more the volume of the space from the tip of the nib main body to the start point in the ball holding chamber.

3. The ballpoint pen nib according to claim 1 or 2, wherein an inner diameter of the ink flow hole is 40% or more of a diameter of the ball.

4. The ballpoint pen nib according to any of claims 1 to 3, wherein the length of the ink flow hole is 90% or less of the diameter of the ball.

5. The ballpoint pen nib according to any of claims 1 to 4, wherein a length of a region of the ink flow hole where the ink flow groove is not formed is 90% or less of a diameter of the ball.

6. The ballpoint pen tip according to any one of claims 1 to 5, further comprising a rebound member having a spring portion and a rod portion extending forward from the spring portion and abutting the ball from the rear.

7. The ballpoint pen nib according to any of claims 1 to 6, wherein a movable range of the ball with respect to the nib body in a front-rear direction is 0.015mm or more and 0.06mm or less.

8. A ball-point pen refill is provided with:

the ballpoint pen tip according to any one of claims 1 to 7; and

an ink containing cylinder that contains ink.

9. The ballpoint pen refill of claim 8, wherein the ink is a thermochromic ink.

10. A ballpoint pen provided with the ballpoint pen refill of claim 8 or 9.