JPH0234066Y2 - - Google Patents

Description

[Detailed description of the invention] This invention is a synthetic resin ink guide for writing instruments, such as a synthetic resin nib or an ink relay member used to guide ink to an appropriate writing tip such as the ball of a ballpoint pen. Regarding the die at the tip of the extrusion molding machine used when forming the core, the purpose is to make it possible to obtain an ink guiding core having sufficient ink guiding ability and sufficient strength.

As the name suggests, the ink guiding core of a writing instrument has an ink passage, and this ink passage is surrounded by an outer skin, that is, it is a hole rather than a groove, and is made by extrusion molding. In some cases, the ink passage may deviate greatly from the desired pattern due to pressure problems during molding.In order to prevent this, air is introduced to connect the outside world and the ink passage. It is necessary to secure a passage, and one means for achieving this is to partition the resin discharge hole for forming the outer skin of the die with a partition wall.

To explain this using the example shown in the attached FIGS. 1 and 2, the die main body A has discharge holes 11, 12, 13 that are integral with each other in the center, and a position between these discharge holes 11, 12, 13. discharge hole 21,
22, 23, and discharge holes 31 to 36 located on the outer periphery of these discharge holes 11 to 23, and partition walls 41 to 46 of these discharge holes 31 to 36 ensure an air introduction path. be.

The number and shape of the ink passages, in other words, the arrangement of the discharge holes of the die, are set as appropriate. For example, the discharge holes 31 to 36 in FIGS. 1 and 2 may be connected to the discharge holes 11 to 23. , or the discharge hole 31
36 may be omitted and the outermost peripheral portions of the discharge holes 11 to 23 may correspond to the discharge holes 31 to 36, but in any case, at least one partition wall is formed. In order to ensure that the resin is well integrated with the resin after being discharged by the partition wall, the design of the partition wall becomes a problem.

That is, when extruding the ink guiding core using the die A shown in FIGS. 1 and 2, the partition walls 41 to
If the width of the partition walls 41 to 46 is relatively wide, an ink guiding core B1 having a cross section as shown in FIG. The ink guide core B2 is obtained, but the outer skin of the ink guide core B1 in FIG. 3 has a partition wall 41.
There are large voids 51 to 56 in many places as remnants of air passing through the parts 46 to 46, and therefore the outer skin of the ink guiding core B1 is not desirable in terms of strength, and the ink guiding core B1 shown in FIG. B2 is a result of insufficient air passing through the partition walls 41 to 46.
The shapes of the ink passages 61 to 66 have become distorted.

In particular, an ink guide core B3 as shown in FIG. 5 as a preferable example in which the widths of the partition walls 41 to 46 are set to an intermediate value as described above, that is,
It is surprisingly difficult to obtain a structure in which the voids remaining in the outer skin are permanently small or zero, and the shape of the ink passage is permanently unobstructed. Both of the disadvantages of obstruction to the shape of the passageway remain.

The present invention has been devised in view of the above-mentioned points, and the attached FIGS. 6 to 8 are examples corresponding to the examples shown in FIGS. 1 and 2. The reference numerals are shown with the 100th place attached to each part corresponding to FIG. 1, but FIG. 6 shows the discharge holes 12, 22, 33,
34 and a portion corresponding to the partition wall 43 are shown in an enlarged manner, and FIG. 7 is a perspective view of the partition wall 143 in FIG. 6, and Figure 8 is the − of Figures 6 and 7.
It shows a cross section taken along a line, and the upper and lower portions of FIG. 8 correspond to the upper and lower portions of FIG. 2. That is, in FIG. 8, the upper side of the page is the inlet side of resin discharge, and the lower side is the outlet side.

The difference between this example and the examples shown in FIGS. 1 and 2 is that tapered portions 7 and 8 are formed in the partition wall 143, so that the partition wall 143 has a narrow width in the resin discharging direction. It's summery. In order to make the width narrower, in addition to using flat tapered parts 7 and 8, it is also possible to use curved surfaces or a combination of flat and curved surfaces as appropriate. It is shown in FIG. FIG. 9 shows a combination of parallel plane parts 71, 81 and tapered plane parts 72, 82. Here, in the case of a planar taper part, that is,
In the case of 7, 8 in Fig. 8, 72, 82 in Fig. 9, etc., the taper angle (α in Fig. 8) is set in order to prevent unnecessary turbulence in the flow of the discharged resin.
is preferably 10° or less, more preferably around 5°. Formation of the tapered portion on the partition wall (not shown) is also the same as described above.

Since the partition wall is for securing an air introduction path, it may originally be made permanently narrow. However, when the width of the partition wall becomes narrow, the air introduction path is obstructed due to an excessive amount of resin being discharged. In the die of the present invention, since the width of the partition wall is narrow in the resin discharge direction, the resin whose discharge amount is regulated at the entrance side of the resin discharge of the partition wall is directed toward the outlet side. Even if the width of the partition wall on the exit side of the resin discharge is narrow, excessive amount of resin discharge is suppressed, and the discharged resin is well integrated with each other because the gap between them is small, and as a result, For example, it is possible to obtain an ink guiding core as shown in FIG. 5, that is, an ink guiding core having an outer skin with excellent strength and an ink passage with excellent ink conductivity. be.

Note that various modifications can be made without departing from the gist of the present invention; for example, as shown in FIG.
It is also possible to make the boundary wall 251 between the discharge hole 212 and the discharge hole 233 into a recess.
It is ranked 200th. ), it can also be applied to those having groove-like ink passages, and in terms of shape, it is possible to obtain an ink guiding core other than a cylindrical ink guiding core, for example, a flat columnar ink guiding core. It can also be used as a dice.

[Brief explanation of the drawing]

Figure 1 is a front view showing an example of the die, Figure 2 is a cross-sectional view taken along the line shown in Figure 1, Figures 3, 4, and 5 are cross-sectional views of the ink guiding core, and Figure 6 is the invention of the present invention. Fig. 7 is a perspective view of the main parts, Fig. 8 is a sectional view taken along the line taken from Fig. 6 and Fig. 7, and Fig. 9 is a diagram corresponding to Fig. 8. A cross section of an example of
FIG. 10 is a perspective view of another example corresponding to FIG. 7. 11, 12, 13, 21, 22, 23, 31,
32,...,36,112,122,133,13
4, 212, 222, 233, 234: resin discharge hole, 41, 42,..., 46, 143, 243: partition wall, 7, 72, 8, 82: tapered part.

Claims (1)

[Scope of utility model registration request] A die used for extrusion molding of an ink guiding core made of a synthetic resin having at least one inner hole as an ink passage, the die having a partition wall that secures an air introduction passage for an outer skin-forming resin discharge hole of the ink passage. The molding die is partitioned by a wall, and the partition wall is narrow in the resin discharge direction.