JPH09202092A - Writing instrument - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent an ink leak from occurring by attaching a cup-shaped elastic sealed cylinder to the interior of a cap, then bringing an almost orthogonal collar with the axial center of a mouthpiece mounted on an opening in a shaft cylinder into tight contact with the open end part of the sealed cylinder when the cap is placed over the shaft cylinder, and hermetically closing a tip part including an air hole on the shaft cylinder side. SOLUTION: A cap 13 is placed at a specified position with a shaft cylinder 1 by engaging the contact stepped part 17 of plural ribs 16 provided on the inner wall of the cap 13 with the collar part 11 of a mouthpiece 10 fitted tightly into a shaft cylinder 1. In addition, an engaging stepped part 18 is formed on the ribs 16 of the cap 13, then the stepped part 20 of a cup-like rubber sealed cylinder 19 is butted against the engaging stepped part 18 and in turn, is fitted into the ribs 16 and engaged with a specified position in the cap 13. Further, the open edge part 21 of the sealed cylinder 19 is slightly projected from the contact stepped part 17 of the cap 13, and the cap 13 is placed over the open edge part 21 of the sealed cylinder 19. If the collar part 11 comes into contact with the contact stepped part 17 of the ribs 16 of the cap 13, the open edge part 21 of the seal rubber 19 is compressed to come into close contact with the collar part 11 of the mouthpiece 10, and an air hole 12 and a pen point 9 are hermetically sealed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention has an ink tank for directly storing ink without absorbing it into batting or the like, and ink pushed out of the ink tank when the air in the ink tank expands due to a temperature rise or the like. The present invention relates to an improvement in a writing instrument cap provided with an ink reservoir for temporarily retaining ink from dropping from a writing tip or an air hole.

[0002]

2. Description of the Related Art A conventional ink direct storage type writing implement cap has a seal cylinder which is movable in the axial direction so that the volume of the seal cylinder does not change when the cap is attached or detached. The cylinder is brought into contact with the conical surface of the base with an appropriate pressing force and sealed.

Here, the cap of the writing instrument of the batting system is attached to the shaft cylinder to seal the pen tip and the air hole, but when the cap is attached to the shaft cylinder to ensure the sealing, it is more than just before the attachment is completed. The inner space of the cap shrinks while the shaft cylinder and the seal portion of the cap are closely fitted and the attachment is completed. Therefore, when the cap is attached, the inside of the cap is pressurized. Conversely, when the cap is removed, the pressure inside the cap is reduced because the space in the cap is expanded while the close fitting portion of the seal portion is released. However, since the inside of the cap and the rear half of the barrel containing the batting are continuous as a space through the air hole of the barrel, the whole writing instrument is pressurized and decompressed, and the ink reservoir and the pen tip The pressure does not change, and the action of ink flowing out of the pen tip or air hole when the cap is attached or detached does not work. However, in the direct storage type writing instrument, the volume in the seal cylinder is not changed when the cap is attached or detached. The air inside is compressed and the air passes through the ink reservoir through the ink reservoir and enters the ink tank as air bubbles, and the ink overflows and is retained in the ink reservoir. Conversely, when removing the cap from the shaft cylinder, the air in the seal cylinder will be depressurized contrary to the above phenomenon, so the ink in the ink tank will be drawn out and also retained in the ink reservoir. The ink is drawn from the pen tip. In this way, each time the cap is attached or removed, the ink retention amount of the ink retention body increases, and finally the retention capacity is exceeded and ink flows out from the air holes or ink leaks from the pen tip. Do it. Therefore, the conventional ink direct storage type writing instrument cap employs the above-described structure in order to prevent this phenomenon.

[0004]

SUMMARY OF THE INVENTION The cap of the conventional direct storage type writing instrument has a relatively hard seal made of polypropylene or polyethylene when the cap is attached and detached so that it does not pressurize and depressurize and seal it. As the structure is such that the cylinder is movable in the axial direction and the opening edge is in close contact with the conical surface of the base of the writing instrument shaft cylinder, the structure is complicated, the number of parts is increased, and the product unit price increases and assembly is complicated. It is also a factor of rising costs. An object of the present invention is to make it possible to provide a cap that solves such a problem.

[0005]

The cap of the writing instrument of the present invention devised to achieve the above-mentioned object is provided with a cup-shaped seal tube made of rubber or the like having a high elasticity in the cap, and the cap is attached to the shaft. When attached to a cylinder, a flange part that is approximately perpendicular to the shaft center of the mouthpiece installed in the shaft cylinder opening comes into close contact with the opening end of the seal cylinder to seal the tip part including the air hole on the shaft cylinder side. When the collar portion of the mouthpiece comes into contact with the seal tube, the end of the seal tube is compressed and the space inside the seal tube is pressurized, but the compression amount of the seal tube is slightly attached to the shaft tube of the cap. By controlling the stop position, the above problem is solved without causing a problem in actual use.

[0006]

FIG. 1 shows an embodiment of the present invention, which will be described in detail with reference to the drawings. The main body of the writing instrument has an ink chamber 2 at the rear of the barrel 1 and an ink reservoir 5 having a number of grooves 3 and a longitudinal groove 4 communicating the grooves 3 on the outer peripheral surface in front.
Is attached, an ink guide core 7 is inserted through a vertical hole 6 axially extending through the center of the ink reservoir 5, and the tip of the ink guide core 7 abuts or sticks to a center core 8. The core 8 is connected to the pen tip 9 at the tip thereof, and the ink is supplied from the ink chamber 2 to the pen tip 9 through the ink guide core 7 and the center core 8.

Next, the cap 13 has an engagement projection 14 formed on the inner surface near the opening edge for engaging with the projection 15 of the barrel 1, and is engaged with the projection 15 of the barrel 1 and on the inner wall of the cap 13. The contact step portions 17 of the plurality of ribs 16 provided are brought into contact with the flange portion 11 of the base 10 which is tightly fitted to the barrel 1 so as to be attached to the barrel 1 at a fixed position. . Further, a locking step 18 is formed on the rib 16 of the cap 13, and the step 20 of the seal cylinder 19 made of cup-shaped rubber is locked on the locking step 18.
Is fitted to the rib 16 and is locked at a fixed position in the cap 13. Here, the opening edge portion 2 of the seal cylinder 19
Reference numeral 1 projects slightly from the contact step portion 17 of the cap 13 by the distance A, and the cap 13 is attached to the collar portion 11 so that the cap 1
When contacting the contact step 17 of the rib 16 of No. 3, the seal rubber 1
The opening edge portion 21 of 9 is compressed by the distance A and comes into close contact with the collar portion 11 of the mouthpiece 10 to seal the air port 12 and the pen tip 9. Distance A
Is about 0.01 to 0.5 mm, preferably 0.05 to 0.1 mm. Further, when the pen tip is a ballpoint pen, the tip of the pen tip 9 is pressed against the bottom of the seal cylinder 19 to close the ink outflow portion of the pen tip 9 as shown in the figure, thereby reliably preventing the ink from flowing out due to a shock or the like. You may do it.

FIG. 4 shows another embodiment. In this embodiment, the contact step portion 22 is brought into contact with the opening end portion 24 of the shaft cylinder 23, the cap 21 is positioned with respect to the shaft cylinder 23, and the opening edge portion 28 of the seal cylinder 27 is brought into close contact with the flange portion 26 of the base 25. The air port and the pen tip are sealed, and the opening edge portion 28 of the seal tube 28 is about 0.01 to 0.5 mm when contacting the collar portion 26 of the mouthpiece 25, preferably 0. 05
Then, the opening edge portion 28 and the flange portion 26 are brought into close contact with each other by being compressed by 0.1 mm.

[0009]

In the writing instrument constructed as described above, when the cap 13 is attached to the writing instrument body, the tip portion including the pen tip 9 and the air hole 12 enters into the seal tube 19 and the opening edge portion 21 of the seal tube 19 is removed. First, the collar portion 11 of the mouthpiece 10 is brought into contact with the collar portion 11, and then the microscopic barrel 1 is further inserted into the cap 13 so that the collar portion 11 is inserted.
Comes into contact with the contact step portion 17 of the cap 13 and stops, and at the same time, the engagement projection 14 of the cap 13 engages with the convex portion 15 of the shaft cylinder 1 to keep the shaft cylinder 1 and the cap 13 in the attached state, The opening edge 21 of 19 is slightly compressed and comes into close contact with the collar 11 to seal the air hole 12 and the pen tip 9. Here is the base 10
When the flange portion 11 of the seal tube 11 comes into close contact with the opening edge portion 21 of the seal tube 19, the opening edge portion 21 is compressed and the inner volume of the seal tube 19 is reduced, and the internal pressure of the seal tube tube 19 is increased.
Since the pushing pressure length of the opening edge portion 21 of the seal cylinder 19 of the collar portion 11 is extremely small, the inside of the seal cylinder 19 is only slightly compressed, and the inflow of the ink into the reservoir 5 is also very small. Therefore, the ink is consumed by writing for actual use, so that the reservoir 5
Since the ink that has entered is returned to the ink chamber 2, the ink is not filled in the reservoir 5 and does not flow out from the air holes 12.

[0010]

The construction and operation of the present invention are as described above. Since there is no need to make the cap movable while applying a pressing force inside the cap unlike the conventional inner cap, the number of parts is reduced and the assembly is simplified. It's easy. Therefore, it is possible to maintain good quality at low cost.

[Brief description of drawings]

FIG. 1 is a vertical sectional view of a writing instrument of the present invention.

FIG. 2 is a partial cross-sectional view of the cap with the shaft body of FIG. 1 removed.

3 is a sectional view taken along line BB of FIG.

FIG. 4 is a longitudinal sectional view of another embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Shaft cylinder 2 Ink chamber 3 Circumferential groove 4 Vertical groove 5 Ink reservoir 6 Vertical hole 7 Ink lead core 8 Medium core 9 Pen tip 10 Base 11 Collar 12 Air port 13 Cap 14 System projection 15 Convex part 16 Rib 17 Contact step 18 Locking step 19 Seal tube 20 Step 21 Opening edge 22 Contact step 23 Shaft tube 24 Opening end 25 Base 26 Collar 27 Seal tube 28 Opening edge

Claims (1)

[Claims] 1. An ink direct storage type water-based ballpoint pen having a tank for directly storing ink at the rear of the shaft cylinder and an ink reservoir at the front of the shaft cylinder when a cap is attached to the shaft. The opening end of the seal cylinder made of highly elastic resin or rubber mounted inside the cap is brought into close contact with the flange surface of the shaft that is almost perpendicular to the shaft core of the base that is mounted in the shaft opening. When sealing, the position of contact between the shaft cylinder and the cap when attached is to be positioned by contacting the flange part of the mouthpiece or the open end of the shaft cylinder with the stepped part or multiple ribs provided in the middle of the cap. A writing instrument cap characterized by: