JP2013132762A - Ball-point pen tip - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a ball-point pen tip in which a ball comes into close-contact with the inner wall surface of the tip end of the ball-point pen tip in nonuse, which is excellent in ink circulation property by applying a stable pressing force to the ball.SOLUTION: In the ball-point pen tip, a cylinder body opened at both ends is disposed so as to move the rear of the ball and an ink circulation hole forward and backward, while the cylinder body presses the ball to the inner wall surface of the tip end by a coil spring disposed at the rear of the cylinder body, and a straight part extending to the ball is provided at the tip end of the coil spring. The straight part is located in the cylinder body and the head of the straight part comes into contact with the ball, to press the ball to the inner wall surface of the tip end.

Description

  In the present invention, the tip of the tip is caulked inward so that a part of the ball protrudes from the tip tip edge and is rotatably held, and the ball is held by the coil spring disposed behind the ball. It is related with the ball-point pen tip formed by pressing on the inner wall surface.

  Conventionally, the structure of a ballpoint pen provided with a coil spring that presses the ball is well known and disclosed in Japanese Patent Application Laid-Open No. 10-329475, “Ballpoint Pen” and the like.

  These ball-point pen tips make the ball in close contact with the inner wall of the tip of the tip by the pressing force of a coil spring disposed at the rear end of the ball, and a gap is formed between the ball and the inner wall of the tip of the tip by writing pressure during writing Japanese Laid-Open Patent Publication No. 2000-158869 “Ball Pen Tip” discloses a structure in which the straight portion does not close the ink circulation groove even if the straight portion of the coil spring moves. Yes.

Further, in a ballpoint pen tip provided with a valve mechanism at the tip end, Japanese Patent Application Laid-Open No. 2006-198835 “Ballpoint Pen Tip” discloses that the tip ball has a ball tip to prevent defects such as writing defects due to burrs in the straight part of the coil spring. It is disclosed that a contact ball is disposed at the rear end, and the contact ball is pressed against the tip ball by a coil spring.
"JP 2000-158869 A" "Japanese Patent Laid-Open No. 2006-198835"

  However, in Patent Document 1, the wire diameter of the coil spring is as small as φ0.1 mm to φ0.3 mm, and there is a problem that the straight portion closes the ink circulation groove. Further, in Patent Document 2, there is a problem that the straight portion of the coil spring moves in the radial direction and deviates from the center of the contact ball, and as a result, the contact ball presses the center of the writing ball. There was no problem.

  In view of these problems, when the wire diameter of the straight portion of the coil spring is increased, the ratio of the coil spring to the inner diameter of the ink circulation hole increases, and a passage for the ink to flow out corresponding to the outflow of ink can be secured. Therefore, there arises a problem that there is a possibility that sufficient ink outflow from the tip of the tip may not be obtained during writing.

  In view of the above problems, the present invention provides a ball-point pen tip that can provide a stable pressing force to the ball and has good ink flowability when the ball is not in use. It is to provide.

  In order to solve the above problems, the present invention has an ink circulation hole provided in the center of the bottom wall of the ball holding chamber and an ink circulation groove extending radially from the ink circulation hole in the chip body, A ball-point pen tip that is configured to place a ball on a wall and caulk the tip end of the tip inward so that a part of the ball protrudes from the tip end and is rotatably held. A cylindrical body having both ends opened is disposed so that the flow hole can be moved back and forth, and the cylindrical body presses the ball against the inner wall surface of the tip end portion by a coil spring disposed at the rear of the cylindrical body. A straight portion extending toward the ball is provided at a tip portion of the coil spring, the straight portion is located in the cylindrical body, and a tip of the straight portion is in contact with the ball, The serial ball, characterized in that for pressing the inner wall surface of the chip tip.

  In addition, an ink groove that extends rearward from the front end of the cylindrical body and communicates with the inside and outside of the cylindrical body while being in contact with the ball is provided at a front end portion of the cylindrical body, and a groove of the ink groove The width is less than or equal to the wire diameter of the coil spring.

  Further, the ink groove communicates with the inside and outside of the cylinder in the radial direction.

  The outer wall of the tip of the cylinder is provided with a flow groove extending rearward from the tip of the cylinder.

  Furthermore, a wear-resistant coating layer is provided on the surface of the cylindrical body.

  According to the first configuration of the present invention, in the ballpoint pen tip, a cylinder having both ends opened is arranged behind the ball and the ink circulation hole is movable back and forth, and is arranged behind the cylinder. By the coil spring, the cylindrical body presses the ball against the inner wall surface of the tip end of the chip, thereby stabilizing the pressing force on the ball and smoothly supplying ink to the ball during writing. Can do. In addition, a straight portion extending toward the ball is provided at the tip of the coil spring, and the straight portion is located in the cylindrical body, so that the cylindrical body and / or the coil spring is radially aligned during assembly or writing. Even if it moves to, the straight part of the coil spring suppresses the deviation between the coil spring and the cylinder, and the cylinder can be surely pressed without entering the coil spring.

  Further, the tip of the straight portion abuts on the ball, and the ball is pressed against the inner wall surface of the tip end portion of the chip to press the ball from multiple directions by the tip of the cylinder and the tip of the straight portion. In addition, since the vicinity of the center of the ball is pressed, a more stable pressing force can be obtained.

  The cylindrical body used in the present invention can be used without particular limitation, such as metal materials such as stainless steel, aluminum, and copper alloys, and synthetic resins such as polypropylene resin, polycarbonate resin, and polyacetal resin. The material of the tip body is not particularly limited, such as stainless steel, copper alloy, aluminum, etc., but considering the performance over time, the cylindrical body and the tip body and / or the coil spring are made of the same material, for example, Stainless steel is preferred. Further, the balls are not particularly limited, such as tungsten carbide cemented carbide, ceramic materials such as zirconia, and stainless steel materials.

  Further, in the present invention, the shape of the ink circulation hole and the cylindrical body is not particularly limited as long as the cylindrical body is disposed in the ink circulation hole so as to be movable back and forth, but in order to stabilize the pressing force to the ball, Most preferably, it is possible to move back and forth as non-contact with the ink circulation hole. Specifically, when the outer diameter of the cylinder is less than 50% with respect to the ink circulation hole diameter, the cylinder moves in the radial direction by the rotation of the ball during writing, and it is difficult to obtain a stable pressing force. If it exceeds 95%, the outer diameter of the cylinder may be 50% or more with respect to the ink circulation hole diameter because the cylinder may not move back and forth smoothly due to the build-up portion that occurs when forming the ink circulation groove or the like. 95% or less is preferable, and 70% or more and 90% or less is most preferable.

  In addition, the pressing force of the coil spring that presses the ball is most preferably set to 5 gf to 50 gf, preferably 10 gf to 30 gf, and 15 gf to 25 gf in consideration of writing feeling and ink leakage. The pressing force of the ball according to the present invention can be measured by the force required to contact the bottom wall of the ball holding chamber or the ball seat from the state of contact with the inner wall of the tip end portion. The clearance in the longitudinal direction of the ball can be appropriately selected depending on the ink viscosity and composition, but is preferably 5 μm to 60 μm. If the pressing force of the coil spring that presses the ball is 5 gf to 50 gf, ink leakage will occur. Considering 10 μm to 40 μm is most preferable.

  According to the second configuration of the present invention, an ink groove that extends rearward from the front end of the cylindrical body to the front end portion of the cylindrical body and communicates with the inside and outside of the cylindrical body in contact with the ball. In addition, the ink width from the cylinder to the ball and the ball holding chamber is maintained even when the tip of the cylinder and the ball are in contact with each other by making the groove width of the ink groove equal to or less than the wire diameter of the coil spring. Distribution can be performed, stable ink can be supplied, and the straight portion of the coil spring can be hardly caught in the ink groove. The number and shape of the ink grooves provided in the cylinder are not particularly limited, but it is preferable that the shapes of the front end portion and the rear end portion of the cylinder are substantially the same in order to improve the assemblability.

  According to the third configuration of the present invention, the ink groove communicates in the radial direction with the cylindrical body and outside the cylindrical body, so that the ball and the ball holding chamber, the ink circulation hole and the cylindrical body from the cylindrical body. Ink can be distributed and ink can be supplied smoothly.

  According to the fourth configuration of the present invention, by suppressing the wear of the cylinder by the ball provided with the wear-resistant coating layer on the surface of the cylinder, the change in the ball pressing force by the cylinder is suppressed and stable. You can get a brushed feeling.

As the wear-resistant coating layer used in the present invention, diamond-like carbon (DLC), tungsten disulfide (WS ₂ ), molybdenum disulfide (MoS ₂ ), titanium nitride layer (TiN) and the like are conventionally known. A wear-resistant coating layer can be used as appropriate. In addition, the method for coating the wear-resistant coating layer is not particularly limited, and examples thereof include vacuum deposition, ion deposition, physical vapor deposition, chemical vapor deposition, vacuum arc deposition, and the like. It may be a coating layer. In particular, among the above-mentioned wear-resistant coating layers, it is most preferable to use diamond-like carbon (DLC) in consideration of lubricity.

  The present invention provides a ball-point pen tip that can provide a stable pressing force to the ball and has good ink flowability in a ball-point pen tip in which the ball is in close contact with the inner wall surface of the tip end when not in use. did it.

It is the figure made into the principal part expanded sectional view which abbreviate | omitted one part which shows the ball-point pen tip of Example 1. FIG. It is an AA arrow expanded sectional view which abbreviate | omitted the ball | bowl in FIG. It is a figure which shows the ball-point pen refill using the ball-point pen tip of Example 1. FIG. It is the figure made into the principal part expanded sectional view which abbreviate | omitted one part which shows the ball-point pen tip of Example 2. FIG. FIG. 5 is an enlarged sectional view taken along the line B-B in which the ball in FIG. 4 is omitted.

  The ball-point pen tip 1 of Example 1 shown in FIG. 1 and FIG. 2 extends radially from the ink circulation hole 6 in the center of the ball holding chamber 3 of the chip body 2 made of ferritic stainless steel wire. Further, a ball seat 5 having a ball curvature and a substantially curvature is provided on the bottom wall 4 in which the ink circulation groove 7 is formed, and a ball 10 having a diameter of 0.7 mm made of tungsten carbide carbide material is mounted on the ball seat 5. Then, the tip end 2A of the tip is caulked inward to hold the ball pen tip 1 by holding it so that a part of the ball 10 protrudes from the tip end edge.

  A cylindrical tubular body 9 is disposed behind the ball 10, and a coil spring 11 is disposed behind the tubular body 9. The coil spring 11 is composed of a coil portion and a close contact portion, and is arranged by regulating the backward movement by caulking the rear end portion of the chip body 2 inward. The elastic force of the coil spring 11 presses the cylindrical body 9 forward, the inside of the tip end surface 9C of the cylindrical body 9 comes into line contact with the ball 10 and presses the ball 10 forward. With such a configuration, when not in use, the ball 10 is in close contact with the inner wall of the tip end portion 2A and is a valve mechanism that provides a gap between the ball 10 and the inner wall of the tip end portion 2A by writing pressure during writing. The pressing force of the cylindrical body 9 and the coil spring 11 that presses the ball 10 was 15 gf.

  The cylindrical body 9 is a cylindrical cylindrical body made of austenitic stainless steel wire with both ends opened in a flat shape, and is arranged to be movable back and forth with respect to the ink circulation hole 6. More specifically, the groove width of the ink circulation groove 7 is 14% (0.098 mm) of the ball diameter, the diameter of the ink circulation hole 6 is 70% (0.49 mm) of the ball diameter, and the outer diameter of the cylinder 9 is the ball. It was 65% (0.455 mm) of the diameter. The inner diameter of the cylindrical body 9 was 46% (0.322 mm) of the ball diameter. The inner diameter of the cylinder 9 is preferably 40% to 70% of the ball diameter, and most preferably 45% to 55%.

  In addition, ink grooves 9A that extend in the longitudinal direction along the rear side from the distal end are provided at four positions in the circumferential direction at the distal end portion of the cylindrical body 9, and these ink grooves 9A are formed in the radial direction of the cylindrical body 9. The slit shape communicates the inside and outside. Further, the overall length of the cylinder 9 in the longitudinal direction is longer than that of the ink circulation hole 6.

  Further, rear ink grooves 9B that extend in the longitudinal direction from the rear end toward the front end and communicate with the inside and the outside are provided at four places in the circumferential direction at the rear end portion of the cylindrical body 9, and the front end portion and the rear end of the cylindrical body 9 are provided. The ends are substantially the same shape, and the front and rear are substantially symmetric. By making the front-end | tip part and rear-end part of the cylinder 9 into substantially the same shape, and making the front and back substantially symmetrical, there is no directionality of a front-end | tip and a rear end, It can use suitably for assembly property, especially a machine assembly.

FIG. 3 shows a ballpoint pen refill in which the ballpoint pen tip 1 of Example 1 is attached to the tip of the ink containing cylinder 12. In the ink containing cylinder 12, a water-based ballpoint pen ink 13 having a shear thinning viscosity of 50 mPa · s and a grease-like ink follower 14 are directly accommodated to obtain a ballpoint refill. The ink viscosity was measured using a Brookfield DV-II viscometer (CPE-42 rotor) in a 20 ° C. environment under a shear rate of 384 sec ⁻¹ (rotation speed: 100 rpm). .

  When writing on the paper surface using this ball-point refill 1, the ball-point pen ink 12 in the ink containing cylinder 2 passes from the rear hole 8 of the ball-point pen tip 1 to the ball 10 and the ball holding chamber 3 through the ink flow hole 6 and the ink flow groove 7. Supplied. At the same time, the ball 10 and the ball holding chamber 3 are supplied from the rear hole 8 of the ball-point pen tip 1 through the rear ink groove 9B to the inside of the coil spring 11A and the cylindrical body 9A, and merged in the ink groove 9B. It is supplied to the holding room 3. The ball-point pen ink 12 is written by the ball 10 moving to the ball seat 5 side by the writing pressure, creating a gap between the inner wall of the tip end 2A of the chip and the ball 10 by the clearance in the vertical direction, and discharging to the outside through this gap. can do. By providing the rear ink groove 9 </ b> B at the rear end of the cylindrical body 9, it is possible to smoothly supply ink from the rear hole 8 of the chip body 2.

  Further, when the ball 10 is rotated by writing, the cylinder 9 is also moved through the ink circulation hole 6 by the rotational force, but the cylinder 9 having an outer diameter larger than the groove width L of the ink circulation groove 7 is the ink circulation groove 7. The ink can be smoothly distributed without being closed. Further, since the groove width M of the ink groove 9A is smaller than the wire diameter N of the straight portion 11A of the coil spring 11, the straight portion 11A is difficult to close the ink groove 9A and the cylinder 9 also moves. Even if the straight part 11A is caught in the ink groove 9A, it is easy to come off.

  The ball-point pen tip 101 of Example 2 shown in FIGS. 4 and 5 is obtained in the same manner as in Example 1 except that the cylinder 109 is provided with an ink groove 109A extending from the front end to the rear end. Yes. By making the cross section C-shaped compared to the cylindrical body, it is easy to distribute the ink into the ink distribution holes 6 and the cylindrical body 109, and the ink supply amount can be increased.

  The ball-point pen tip 201 of Example 3 shown in FIG. 6 is similar to Example 2 except that a wear-resistant coating layer T made of DLC (diamond-like carbon) is provided on the surface of the cylindrical body 209. It has gained.

  By providing the wear-resistant coating layer T made of DLC (diamond-like carbon) on the surface of the cylindrical body 209, it is possible to suppress the abrasion of the cylindrical body 209 and reduce the contact resistance with the ball 10, and a stable pressing force, Smooth ball rotation can be obtained.

  In addition, since a plurality of flow grooves extending rearward from the front end of the cylinder are provided, the ink for the ballpoint pen is written from the rear hole of the ballpoint pen tip 101 to the ink flow hole 6, the ink flow groove 7, and the cylinder during writing. , And are supplied to the ball 10 and the ball holding chamber 5 through the ink groove and the flow groove.

  In the present embodiment, for convenience, the rear end portion of the chip is crimped inward to hold the coil spring, but the method of holding the coil spring is not particularly limited, such as holding it in contact with the chip holder. Further, in the present embodiment, for convenience, the ink circulation groove reaching the rear hole of the ball-point pen chip is improved in the ink circulation property from the rear hole, but it may be shaped so as not to reach the rear hole. Furthermore, in this embodiment, since wear due to the rotation of the ball can be suppressed, a ball seat is provided on the bottom wall of the ball holding chamber as a preferred form for convenience. However, a shape without the ball seat may be used. .

  Furthermore, in this embodiment, for the sake of convenience, the wear-resistant coating layer is provided only on the cylindrical body, but the wear-resistant coating layer is provided on the surface of the ball and / or the bottom wall of the ball holding chamber to provide a ball seat. It is preferable to suppress such wear.

The type of the ink for the ballpoint pen of the present invention is not particularly limited, such as oiliness and water, and the ink viscosity is not particularly limited, but when the viscosity at the time of writing is less than 10 mPa · s. , The ink viscosity is too low and it tends to cause bleeding or affect the handwriting dryness. When the ink viscosity exceeds 5,000 mPa · s, the ball rotation resistance during writing increases and the writing feeling Tends to be heavy and tends to have an effect on ink followability. Therefore, the ink viscosity at the time of writing is preferably 10 to 5,000 mPa · s. Considering the above tendency, it is preferably 30 to 3,000 mPa · s, and most preferably 50 to 2,500 mPa · s. The ink viscosity was measured using a Brookfield DV-II viscometer (CPE-42 rotor) under an environment of 20 ° C. under a shear rate of 384 sec ⁻¹ (rotation speed: 100 rpm). .

  The ball-point pen tip of the present invention is not particularly limited, such as the type of ink and the ball diameter, and thus can be widely used as a ball-point refill and can be suitably used as a ball-point pen tip used for a knock-type ball-point pen.

DESCRIPTION OF SYMBOLS 1,101 Ball-point pen tip 2 Tip body 2A Tip end 3 Ball holding chamber 4 Bottom wall 5 Ball seat 6 Ink flow hole 7 Ink flow groove 8 Rear hole 9, 109 Cylindrical body 9A, 109A Ink groove 9B Rear ink groove 9C, 109C End face 10 Ball 11 Coil spring 11A Straight part 12 Ink receiving cylinder 13 Ink for ballpoint pen 14 Ink follower L Groove width of ink distribution groove M Groove width of ink groove N Straight wire diameter T Wear-resistant coating layer

Claims (4)

The chip body has an ink circulation hole provided in the center of the bottom wall of the ball holding chamber, and an ink circulation groove extending radially from the ink circulation hole, the ball is placed on the bottom wall, and the tip of the chip is In a ball-point pen tip that is held in a rotatable manner by projecting a part of the ball from the tip end by caulking inward, both ends are opened so that the ink circulation hole can be moved back and forth. A cylindrical body is disposed, and the cylindrical body presses the ball against the inner wall surface of the tip end portion of the chip by a coil spring disposed at the rear of the cylindrical body, and the ball on the distal end portion of the coil spring. A straight portion extending toward the tip, the straight portion is located in the cylindrical body, a tip of the straight portion abuts on the ball, and the ball is attached to an inner wall surface of the tip tip portion. Ballpoint pen tip, characterized in that the pressing. An ink groove that extends rearward from the tip of the cylinder and is in contact with the ball is provided at the tip of the cylinder and communicates with the inside and outside of the cylinder, and the groove width of the ink groove is increased. The ball-point pen tip according to claim 1, wherein the diameter is equal to or smaller than a wire diameter of the coil spring. The ball-point pen tip according to claim 2, wherein the ink groove communicates with the cylindrical body and the cylindrical body in a radial direction. The ballpoint pen tip according to any one of claims 1 to 3, wherein a wear-resistant coating layer is provided on a surface of the cylindrical body.

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