JP4793959B2 - Ballpoint pen tip - Google Patents

Description

  The present invention relates to a ballpoint pen tip formed by holding a ball rotatably in a ball holding chamber at the tip of the tip.

  Conventionally, a ballpoint pen tip having an ink circulation groove communicating with an ink circulation hole at the center of the bottom wall of the ball holding chamber is well known. In such a ball-point pen tip, an ink circulation groove of a type that extends radially from the ink circulation hole and does not reach the inner hole at the rear end of the chip, as in Japanese Utility Model Publication No. 7-31382, “Ball Pen” is well known.

In such a ball-point pen tip having an ink distribution groove that extends radially from the ink distribution hole and does not reach the inner hole at the rear end of the chip, Japanese Patent Application Laid-Open No. 8-207482 “Metal chip for ball-point pen” includes an ink distribution hole. There is disclosed a ballpoint pen tip in which the diameter of the ink and the length of the ink circulation hole are made to be a fixed ratio, and the ink repelling after being left facing upward is prevented from blurring and the ink followability at high speed writing is improved.
“Japanese Utility Model Publication No. 7-31382” "JP-A-8-207482"

  By the way, the type of ink circulation groove that extends radially from the ink circulation hole and does not reach the inner hole at the rear end of the chip has a substantially U-shaped cross section as disclosed in Patent Documents 1 and 2, The surface is generally L-shaped. As shown in FIGS. 6 and 7, such an ink circulation groove has the same shape as the shape of the tool 109 (106 a, 106 a) by abutting and pressing the tool 109 against the bottom wall 103 of the ball holding chamber 102 of the ballpoint pen tip 101. 106 b), an ink circulation groove 106 extending radially from the ink circulation hole 103 and not reaching the inner hole 107 at the rear end of the chip is formed.

  The tool 109 for forming the ink circulation groove 106 generally has a tip angle of 90 degrees in consideration of durability and the like. Therefore, the inclination angle of the bottom wall surface 106b of the ink circulation groove 106 is 45 degrees. The angle of the joint S between the outer wall surface 106a and the bottom wall 106b farthest from the ink circulation hole 103 of the ink circulation groove 106 was 135 degrees, and was formed with a steep slope.

  As a result of examining the ink circulation groove and the ink followability, the present inventor has found that the inclination angle in the longitudinal section of the ink circulation groove and the ink followability are closely related. This causes turbulence in the vicinity of the joint between the outer wall surface and the bottom wall surface that are farthest from the ink circulation hole in the longitudinal section when the writing instrument ink communicates with the ink circulation groove from the inner hole at the rear end of the chip. It is thought that it is because.

  An object of the present invention is to provide a ballpoint pen tip having excellent ink followability regardless of the type and viscosity of the ink.

  The present invention includes an ink circulation hole that rotatably holds a ball in a ball holding chamber at a tip end of the chip, communicates with an inner hole in a rear end portion of the chip at the center of the bottom wall of the ball holding chamber, and the ink In the ball-point pen tip having an ink circulation groove that extends radially from the circulation hole and does not reach the inner hole of the rear end portion of the chip and has a substantially U-shaped cross section, the ink circulation groove is the most with respect to the ink circulation hole. In addition to having a connecting surface connecting the separated wall surface and the bottom wall surface, α <β is satisfied, where α is the inclination angle of the connecting surface and β is the inclination angle of the bottom wall surface.

In addition, an ink circulation hole that rotatably holds a ball in a ball holding chamber at the tip end of the chip, communicates with an inner hole in the rear end of the chip at the center of the bottom wall of the ball holding chamber, and the ink circulation hole In the ball-point pen tip having an ink circulation groove that extends radially from the inner end of the chip and does not reach the inner hole at the rear end of the chip, the ink circulation groove is most spaced from the ink circulation hole. a wall, a bottom wall of a fixed inclination angle with respect to the ink flow hole, which has a connecting surface for connecting the said wall and the bottom wall, wherein the coupling surface is arcuate der is, the bottom wall of the ball The ink circulation groove communicates with the ball holding chamber in a mounted state .

  It was possible to provide a ballpoint pen tip having excellent ink followability regardless of the type and viscosity of the ink.

  Next, embodiments of the ballpoint pen tip and the ballpoint pen using the same according to the present invention will be described with reference to the drawings. However, the present invention is not limited to the following embodiments.

  The ball-point pen tip 1 shown in FIGS. 1 and 2 has a ball 8 placed on the bottom wall 3 of the ball holding chamber 2 of the chip body, and the tip end edge 4 is caulked inward, so that the ball 8 can be rotated. I have a hug. The bottom wall 3 of the ball holding chamber 2 has an ink circulation hole 5 communicating with the inner hole 7 at the rear end of the chip, and extends radially from the ink circulation hole 5 to the inner hole 7 at the rear end of the chip. Four ink flow grooves 6 that do not communicate are formed.

  As shown in FIG. 3, the ink circulation groove 6 has a tool 9 in contact with the bottom wall 3 of the ball-point pen tip and pressed so that the transverse section is substantially U-shaped and the longitudinal section is substantially L-shaped (see FIG. 3). Thus, the ink flow groove 6 having the same shape (6a, 6b, 6c) as the shape of the tool 9 is formed, and the outer wall surface 6a farthest from the ink flow hole 5 of the ink flow groove 6 is formed. And a connecting surface 6b that connects the bottom wall surface 6c.

  When the inclination angle α of the connecting surface 6b and the inclination angle of the bottom wall surface 6c are β, α <β is satisfied, so that the writing instrument ink (not shown) passes from the inner hole 7 at the rear end of the chip to the ink distribution groove 6. Since the angle gradually increases from the bottom wall surface 6c toward the outer wall surface 6a farthest from the ink circulation hole 5, the flow of ink for writing instruments (not shown) becomes smooth and turbulent. Ink followability is improved.

  The ball-point pen tip 11 of Example 2 shown in FIG. 4 is carried out except that the connecting surface 16b connecting the outer wall surface 16a and the bottom wall surface 16c farthest from the ink circulation hole 15 of the ink circulation groove 16 has an arc shape. In the same manner as in Example 1, the ball 8 is placed on the bottom wall 13 of the ball holding chamber 12 of the chip body, and the tip end edge 14 is caulked inward to hold the ball 8 in a rotatable manner. An ink circulation hole 15 communicating with the inner hole 17 at the rear end of the chip is formed in the bottom wall 13 of the holding chamber 12, and four holes extending radially from the ink circulation hole 15 and not communicating with the inner hole 17 at the rear end of the chip. A ballpoint pen tip 11 is obtained by forming the ink distribution groove 16.

  Further, as shown in FIG. 5, the ink circulation groove 16 is pressed by pressing the tool 19 against the bottom wall 13 of the ballpoint pen tip so that the transverse section is substantially U-shaped and the longitudinal section is substantially L-shaped. 5 (in the direction of arrow F), the ink circulation groove 16 having the same shape (16a, 16b, 16c) as the shape of the tool 19 is formed, and the ink circulation groove 16 is most spaced from the ink circulation hole 15 An arc-shaped connecting surface 16b that connects the outer wall surface 16a and the bottom wall surface 16c is formed.

  The connection surface 16b that connects the outer wall surface 16a and the bottom wall surface 16c that are the farthest away from the ink flow hole 15 of the ink flow groove 16 is formed into an arc shape, so that the connection surface 16b and the ink flow hole 15 are separated the most. Since a corner | angular part is not formed in the junction part with the outer wall surface 16a and the bottom wall surface 16c, since distribution | circulation of writing instrument ink (not shown) becomes smoother, it is preferable.

  Further, the volume of the ink circulation groove is increased as compared with the case where the outer wall surface 16a farthest from the ink flow hole 15 of the connection surface 16b and the ink flow groove 16 and the connection surface 16b and the bottom wall surface 16c are connected by a straight line. Since more ink for writing instruments can flow, ink followability improves.

  In the present embodiment, for convenience, the ball seat is not formed, but the ball seat may be formed on the bottom wall of the ball holding chamber. Also, the shape and number are not particularly limited as long as the ink circulation groove extends radially from the ink circulation hole and does not reach the inner hole at the rear end of the chip.

  Can be implemented without limitation on ink type and ink viscosity, such as oil-based ink, shear-thinning ink, and water-based ink, and is particularly effective for shear-thinning ink and low-viscosity oil-based inks that are often ejected onto paper when writing. Can be used.

It is the longitudinal cross-sectional view which abbreviate | omitted partially which shows the ball-point pen tip of Example 1. FIG. It is AA sectional drawing which abbreviate | omitted one part in FIG. It is a figure which shows the state which forms the ink distribution groove | channel in FIG. It is the longitudinal cross-sectional view which abbreviate | omitted partially which shows the ball-point pen tip of Example 2. FIG. It is a figure which shows the state which forms the ink distribution groove | channel in FIG. It is the principal part expanded sectional view abbreviate | omitted in the conventional ball-point pen tip. It is a figure which shows the state before forming the ink distribution groove | channel in FIG.

Explanation of symbols

1, 11, 101 Ballpoint pen tip 2, 12, 102 Ball holding chamber 3, 13, 103 Bottom wall 5, 15, 105 Ink flow hole 6, 16, 106 Ink flow groove 6a, 16a, 106a Outer wall surface 6b, 16b Connection Surface α Connection surface angle 6c, 16c, 106b Bottom wall surface β Bottom wall surface angle 7, 17, 107 Inner hole at the rear end of the chip 8 Ball 9, 19, 109 Tool

Claims (2)

A ball is rotatably held in a ball holding chamber at the tip of the chip, an ink circulation hole communicating with an inner hole in the rear end of the chip at the center of the bottom wall of the ball holding chamber, and a radial shape from the ink circulation hole In the ball-point pen tip having an ink circulation groove having a substantially U-shaped cross section that does not reach the inner hole at the rear end of the chip, the ink circulation groove is separated from the wall surface that is farthest from the ink circulation hole. A ballpoint pen tip having a connecting surface connecting to a bottom wall surface, wherein α <β is satisfied when α is an inclination angle of the connecting surface and β is an inclination angle of the bottom wall surface. A ball is rotatably held in a ball holding chamber at the tip of the chip, an ink circulation hole communicating with an inner hole in the rear end of the chip at the center of the bottom wall of the ball holding chamber, and a radial shape from the ink circulation hole In the ball-point pen tip having an ink circulation groove having a substantially U-shaped cross section that does not reach the inner hole at the rear end of the chip, the ink circulation groove is separated from the wall surface that is farthest from the ink circulation hole. a bottom wall surface of constant slope angle with respect to the ink flow hole, which has a connecting surface for connecting the said wall and the bottom wall, wherein the coupling surface is placed a circular arc shape der is, the ball in the bottom wall In this state, the ink circulation groove communicates with the ball holding chamber .

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