JP2014104672A - Ball-point pen tip - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a ball-point pen tip for preventing a ball pressing member from being separated from a center portion of a ball, having a tip opening part of a ball holder which is made uniform, and suppressing blobbing.SOLUTION: A ball-point pen tip comprises ball pressing members 6b and 6C disposed in a state movably in forward and backward directions while the ball pressing members are sandwiched in a through-hole inner wall of a ball holder 2.

Description

  In the present invention, a ball pressing member for urging the ball forward is disposed in a through hole of a ball holder that rotatably holds the ball as a writing member in a state in which the ball is partially protruded from the tip opening. The present invention relates to a ball-point pen tip that causes a ball, which is a writing member, to circumferentially contact the inner wall of the ball holder.

Conventionally, in order to prevent inability to write due to drying of ink in a ball-point pen tip, Japanese Patent Application Laid-Open No. 8-244394 (Patent Document 1) forms a straight portion at the tip of a coil spring, and the straight It is disclosed that the ball is urged toward the tip side by the portion, the ball is brought into circumferential contact with the inner wall near the opening of the ball holder, and the gap between the ball and the ball holder is sealed.
However, the tip of the straight portion does not necessarily press the center of the ball, and there is a problem that the sealing function of the gap between the ball and the ball holder becomes insufficient as the distance from the center of the ball increases.
In view of this, Japanese Patent Application Laid-Open No. 2001-146087 (Patent Document 2) discloses a device in which the tip straight portion of the coil spring is folded and the width of the folded portion is smaller than the inner diameter of the ink circulation hole.

JP-A-8-244394 JP 2001-146087 A

In the invention described in Patent Document 2, since the straight portion is folded back, the width of the tip portion with respect to the ink circulation hole is increased, and compared with a case where the ball is simply pressed by the straight portion, the tip of the elastic member is moved from the center portion of the ball. Although the effect of reducing the distance between the parts is reduced, the width of the folded part is smaller than the inner diameter of the ink circulation hole, so the difference between the width of the folded part and the inner diameter of the ink circulation hole, the tip of the elastic member Is not in a state of completely pressing the central portion of the ball.
Also, during writing, the tip of the impact member is pulled in the direction of rotation of the ball due to the rotation of the ball, away from the center of the ball, and a force that pushes the ball in the opposite direction to which the tip of the impact member has moved is applied. The clearance at the front end opening of the holder is reduced, and excess ink that has not been transferred to the paper surface may not be collected in the ball holder, resulting in a so-called void.

  In the present invention, a ball pressing member for urging the ball forward is disposed in a through hole of a ball holder that rotatably holds the ball as a writing member in a state in which the ball is partially protruded from the tip opening. In the ballpoint pen tip that makes the ball, which is a writing member, come into circumferential contact with the inner wall of the ball holder, the ball pressing member is arranged in a state of being able to move back and forth while being held by the inner wall of the through hole of the ball holder. The main point is the ballpoint pen tip.

  The ball pressing member that urges the ball forward is formed wider than the inner diameter formed by the inner wall of the appropriate position of the ball holder so that the ball pressing member does not move in the radial direction in the through hole. Since the ball is in contact with the central portion of the ball and biased forward, the tip opening of the ball holder becomes uniform during writing, thereby suppressing the stickiness.

The longitudinal cross-sectional view of the ball-point pen (refill which abbreviate | omitted the exterior body) of this invention. The principal part expanded longitudinal cross-sectional view of FIG. II-II 'line | wire arrow line view of FIG. The principal part expansion longitudinal cross-sectional view of the other Example of this invention. The III-III 'arrow directional view of FIG.

The basic structure of a ballpoint pen tip consists of a ball that serves as a writing member that contacts the writing surface, such as paper, and transfers the ink, and a ball holder that rotatably holds the ball. Ink is applied to the writing surface through a through hole of a ball holder as a path.
The through hole of the ball holder communicates with the inner hole of the ink tank by connecting the ball holder to a member that becomes the ink tank directly or via a connecting member. In addition, the ball holder has an inward protruding portion formed in the middle of the through hole to serve as a ball retraction restricting portion, and the tip opening portion is a crimped portion processed to a diameter smaller than the ball diameter. Holds the ball and prevents it from slipping out.

  The ball material can be cemented carbide with tungsten carbide, titanium, cobalt, chromium, nickel, etc. as the main component, and ceramics such as silicon carbide, silicon nitride, titanium nitride, alumina, zirconia, etc. It is preferable to use one adjusted to the ink.

  In the ball holder, a radial groove communicating with an inner hole which is a through-hole is divided into an inward projecting portion substantially equally and arranged circumferentially. A ball pressing member, which will be described later, is disposed in the inner hole and urges the ball forward. The inner hole can be used as a path for allowing ink to flow into the ball holding chamber and can be a place where the ball pressing member is arranged in a sandwiched manner, and the inner wall diameter of the inner hole is set smaller than the width of the ball pressing member. Thus, the ball pushing member is disposed in a sandwiched manner at an appropriate position on the inner wall of the inner hole. Further, the radial groove is formed at a position facing the radial direction of the middle hole. Specifically, by forming an even number, the ball pressing members can be disposed in a sandwiched manner in grooves facing each other about the axis, and the ball pressing members can be prevented from rotating in the circumferential direction. At this time, in order to facilitate alignment between the ball pressing member and the groove, it is preferable that a radial groove is formed in the rear hole in a penetrating state so that the groove position can be confirmed from the rear hole side of the ball holder.

The material of the ball holder can be made of metal such as stainless steel, brass, or white, or synthetic resin with high wear resistance called engineering plastic, such as polyoxymethylene. There is a type that uses a rod-shaped blank material by cutting a wire, and a type that uses a metal pipe material having a medium hole in advance.
In the case of a metal ball holder, the radial groove is formed by inserting a cutting jig having a radial cutting blade into the inward protruding part or by pushing a cone-shaped pressing jig with a sharp tip from the outer surface. There is a method in which radial grooves are formed simultaneously with the lateral protrusions. In the case of a synthetic resin ball holder, a radial groove is formed in the inward projecting portion together with a through hole formed by a core pin whose internal shape is processed into a dimension considering the shrinkage rate of the resin used.
In the case where the ball pressing member is disposed so as to be sandwiched between the grooves facing each other about the axis, the cutting blades of the cutting jig and the radial grooves of the core pin are arranged so that there is no rattling of the ball pressing members located in the radial grooves. Set the width and shape and the amount of pressing jig indentation. Specifically, the width of the radial groove is made smaller than the diameter of the ball pressing member and is brought into contact with the radial groove opened in the middle hole, or the radial groove has a reduced width in the radial direction. There is a method of making contact with a tapered surface that reduces the width.

The tip of the ball pusher that urges the ball forward is located in the inner hole that forms a narrow space where the inward protruding part of the ball holder is formed, so the tip becomes a rod-like part and is integrated with the elastic part But it may be a separate body.
Metal or resin can be used for the elastic part, and a coil spring, a rubber-like elastic body, a leaf spring, or the like can be used. Similarly, the tip can be made of metal, resin, etc. The shape of the tip can vary from triangular, quadrangular, elliptical, etc. Although the inner hole is a passage for ink and the tip part is inserted, the actual ink flow cross-sectional area decreases and there is a risk of hindering sufficient ink supply. By folding the part, providing a gap between the turns, increasing the ink flow cross-sectional area and making it elastically deformable in the radial direction, it will be securely sandwiched between the aforementioned inner hole inner wall and the opposed radial groove, More preferred.
In addition, since the tip portion is arranged in a sandwiched manner on the inner wall of the inner hole, the tip portion also moves back and forth while sliding along the inner wall of the inner hole in conjunction with the longitudinal movement of the ball during writing. The force F is obtained by multiplying the friction coefficient μ by a vertical drag N that is the force of the tip portion pushing the inner wall, and it is necessary that the force for biasing the ball forward> the friction force F. The coefficient of friction μ is about 0.15 in the case of stainless steel, which is a general material used for the ball holder and the ball pressing member, and about 0.12 when ink serving as a lubricant is present, and the tip portion of the stainless steel has an inner wall. Even if the pushing force is the same load as the force for urging the ball forward, only about 10 to 20% of that force is applied, and there is no obstacle to the back and forth movement of the ball.

As a method of assembling the ball pressing portion, the ball pressing member is inserted from the rear end side of the ball holder. In the case of sandwiching the radial grooves facing each other, the direction of the ball pressing member is aligned and pushed in so that the location of the radial pressing groove of the ball pressing member matches the radial groove opening.
After that, the diameter of the rear end face of the ball holder is reduced so that it is smaller than the outer diameter of the ball pressing member, or a step is provided inside the ink containing tube or relay member connected to the ball holder. The rear end of the ball pressing member can be brought into contact with the stepped portion as appropriate.

Ink tank materials that connect such ballpoint pen tips directly or via relay members are polyamide resin, vinyl chloride resin, ethylene vinyl alcohol copolymer, polyacrylonitrile, fluorine resin, polyacetal resin, polyethylene, polypropylene. Various materials such as resins such as polyethylene terephthalate, polycarbonate resin, polystyrene resin, ABS resin, polybutylene terephthalate, polybutylene naphthalate, polyethylene naphthalate, and metals such as stainless steel can be used.
In addition, it is also appropriate to apply coloring to the formed pipe or to apply silicon or the like that suppresses ink adhesion to the side wall of the pipe in order to improve the remaining ink visibility.

  As the ink to be used, either water-based ink using water as a main medium or oil-based ink using an organic solvent such as alcohol as a main medium can be used, and pigments and / or dyes as coloring components, anti-freezing, etc. Contains high-boiling organic solvents, resin components that provide fixability to the writing surface, surfactants and polysaccharides that adjust surface tension, viscoelasticity, lubricity, etc., and rust / anti-mold agents It is also possible to use a ball-point pen filled with ink generally referred to as a correction liquid that contains a white concealing component such as titanium oxide for the purpose of correcting typographical errors.

  A ballpoint pen is manufactured by pressing a ballpoint pen tip into an ink containing tube filled with ink and then filling a high-viscosity liquid for preventing ink backflow from the rear end of the ink containing tube to form a ballpoint pen (refill). Can be obtained by applying a centrifugal force toward the center side to remove bubbles inside the ink from the rear end side of the ink containing tube, and mounting an exterior body as necessary.

Hereinafter, an example will be described based on the drawings.
As shown in FIG. 1, a refill formed by joining a ballpoint pen tip and an ink containing portion is illustrated, and the exterior is omitted.
The tip of the ball holder 2 has a ball holding chamber 2a as a space for holding the ball 1 as a writing member. The tip opening 2b which is the tip of the ball holding chamber 2a , The diameter is reduced to a diameter smaller than the diameter of the ball 1 by caulking (reducing diameter by plastic deformation), and the ball 1 is prevented from falling out while partially protruding from the ball holder 2. Has been made.
In addition, the ball holding chamber 2a is formed with a plurality of inward protruding portions 2c formed by cutting or plastic working so as to restrict the backward movement of the ball 1 and each inward protruding portion 2c. A space between the two is used as an ink flow path, and a radial groove 2e having a constant groove width communicating with the inner hole 2d is formed. Behind the radial groove 2e, a rear hole 2f communicating with the intermediate hole 2d is gradually reduced in diameter by a cutting tool or the like from the ball 1 side and the opposite direction to the ball 1 side by a cutting tool having a different diameter for each processing step. It is formed as follows. From the ink containing tube 4 containing the ink 3, it passes through the rear hole 2 f, passes through the middle hole 2 d and the radial groove 2 e, flows into the ball holding chamber 2 a, and is discharged from the tip opening 2 b as the ball 1 rotates.

  An ink storage tube 4 is connected behind the ball holder 2. The ink storage tube 4 is filled with ink 3 and a high-viscosity fluid 5 for preventing ink backflow. If necessary, one or a plurality of relay connection parts may be interposed between the ink storage unit 4 and the ball holder 2, but the illustrated example is directly connected.

  Inside the ball holder 2, there is disposed a ball pressing member 6 which is a coil spring integrally formed with a folded portion 6c formed by folding a rod-like portion 6b on the tip side of the coil portion 6a. The ball 1 is pressed and biased toward the ball 1, and the ball 1 is in contact with the inside of the tip opening 2 b of the ball holder 2. The inside of the tip opening 2b is required to be in a state where ink does not flow out due to hermeticity with the ball 1, so that when the tip of the ball holder 2 is caulked, a ball holder is used with a pressure contact tool (not shown). By pressing the inner side of the tip of 2 to the ball 1 and plastic working, a belt-like portion 2g having a width having the same curvature as that of the ball 1 is formed on the inner side of the ball holder 2.

  As shown in FIG. 2 which is an enlarged view of the main part (I part) of FIG. 1 and FIG. 3 which is an II-II ′ arrow view, the cross-sectional shape of the rod-like part 6b of the ball pushing member 6 is circular and the wire diameter A is Further, the diameter is set to be larger than the groove width B of the radial groove 2e, and the folded portion 6c has a gap between the folded portions, and has elasticity in the radial direction. The folding width C is set wider than the inner wall diameter D of the inner hole 2d. The ball pressing member 6 is disposed so as to be sandwiched by the inner wall of the inner hole 2d because the folding width C> the inner wall diameter D, and the ball pressing member 6 is folded into the opening of the inner hole 2d of the radial groove 2e because the wire diameter A> the groove width B. The portion 6c abuts to prevent expansion in the radial direction due to elasticity, and at the same time, the ball pushing member 6 is also prevented from rotating, so that the ball pushing member 6 does not move and completely contacts the central portion of the ball 1. Since they are brought into contact and biased forward, the gap between the ball 1 and the tip opening 2b of the ball holder 2 is completely sealed in a non-writing state to prevent ink leakage. In addition, since the ball pressing member 6 is sandwiched even in the writing state, the ball pressing member 6 does not move from the center of the ball 1 and is in contact with it, so that the tip opening 2b of the ball holder 2 becomes uniform, and the sticking is suppressed. .

FIG. 4 shows an enlarged view of a main part of another embodiment and FIG. 5 which is a view taken along the line III-III ′ of FIG.
In this example, the radial width of the radial groove 2e is reduced in the radial direction, and the folded portion 6c of the ball pressing member 6 is in contact with the tapered surface of the radial groove 2e, so that the ball pressing member can be surely secured. 6 is a rotation stop.

DESCRIPTION OF SYMBOLS 1 Ball 2 Ball holder 2a Ball holding chamber 2b Front opening part 2c Inner protrusion part 2d Middle hole 2e Radial groove 2g Band-shaped part 2f Rear hole 3 Ink 4 Ink accommodating part 5 High viscosity fluid 6 Ball pushing member 6a Coil part 6b Bar shape Part 6c Folding part

Claims (1)

A ball pressing member that urges the ball forward is disposed in a through hole of a ball holder that rotatably holds the ball as a writing member in a state in which the ball is partially protruded from the tip opening, and in a non-writing state, the writing member A ballpoint pen tip for causing the ball to circumferentially contact the inner wall of the ball holder, wherein the ball pressing member is disposed in a state of being able to move back and forth while being sandwiched between the inner walls of the through holes of the ball holder.

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