JP3514517B2 - Ballpoint pen - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a ballpoint pen using low-viscosity ink or ink having shear-thinning viscosity, which can prevent direct current and backflow of ink. About the ballpoint pen. [0002] The applicant of the present invention discloses, in Japanese Utility Model Publication No. 4-52067, a mechanism for preventing ink from flowing back in a ball-point pen provided with a valve chamber into which a ball is loosely fitted. In this case, a required number of ridges are provided in a valve chamber in which a ball is loosely fitted with a synthetic resin tip shaft so that the ball cannot be pulled out, and a gap formed between the ridges during writing. And the ink is caused to flow to the chip. Further, a ballpoint pen using an ink having a shear thinning viscosity, in which the viscosity is reduced by rotation of the tip ball during writing and the ink is discharged, is known. In general, a ballpoint pen using ink having shear thinning has a large amount of ink flowing out (in order to increase the writing density), and has a large diameter of the ink storage tube to increase the mounting amount of ink. or,
Since the viscosity of the ink is smaller than that of the oil-based ballpoint pen ink, the flow resistance to the ink storage tube is small. Therefore,
Ink leakage (ink flows backward at the rear end of the ink storage tube) easily occurs due to the weight and impact of the ink. For this purpose, a grease-like follower is provided at the rear end of the ink, which normally moves following the consumption of ink during writing, but suppresses the backflow of the ink against its own weight or impact. However, even if the follower is provided, when the ink is written immediately below the ball of the tip when writing upward, there is a danger that the ink or the head will be added directly, causing a remarkable backflow and soiling the hands and clothes. In addition, since the viscosity of the ink is low and the amount of outflow is large, if the tip side is directed downward and a gap is formed between the tip ball and the tip caulking portion, the ink bleeds (DC).
The problem exists. SUMMARY OF THE INVENTION An object of the present invention is to use ink having low viscosity or ink having a shear-thinning viscosity in which the viscosity is reduced by rotation of a ball during writing and the ink flows out. Improvement of ballpoint pens, which can prevent backflow of ink caused by upward writing or impact of ballpoint pens and direct current when the tip side is placed downward, and can prevent contamination of the ball-point pen barrel, hands, and clothes. . [0004] Ballpoint the present invention in order to achieve the above object In order to achieve the above, the ballpoint pen tip to the tip of the joint, has an ink storage tube to the rear end, the ink containing tube
Has low viscosity ink or static high viscosity
When the tip ball rotates, the viscosity drops and ink spills.
Is filled with ink having a shear thinning
A follower is provided to follow the end, a valve chamber is provided at the rear in communication with the rear end of the chip at the joint axis, and a tapered or spherical ball receiving seat is provided at the rear of the valve chamber, and a ball receiving seat is provided. In a ball-point pen with a backflow prevention mechanism for ink, a ball valve that can be brought into close contact with the valve chamber is loosely fitted into the valve chamber, a spring is urged to the tip bore, and the tip of the spring is rotated toward the tip of the tip. The tip end ball is pressed freely against the rear end of the tip ball so that the tip ball comes into close contact with the inner edge of the ball holding portion of the chip, and the shaft side surface at the rear end of the shaft portion of the chip
Notches are provided at required places and the rear end is caulked
The rear end of the spring cannot be pulled out at the crimped portion at the tip end of the tip, and when the tip side is upward, the ball valve is in close contact with the ball receiving seat and the guide hole is sealed, and when the tip side is downward, the seal is closed. When the state is released, the ball valve comes into contact with the rear end of the chip, and ink can flow into the chip inner hole through the guide hole and the notch at the rear end of the chip. FIG. 1 and FIG. 2 show a first embodiment of the present invention. First, as shown in the figure, a locking cylinder 7 is provided in the first half of the joint 3 and a fitting cylinder 12 is provided in the second half, and the locking cylinder 7 on the front side is provided.
Is provided with a rib 8 inclined forward in the axial direction at a required position on the circumference. A chip fitting hole 10 is formed from the front end of the locking cylinder 7, and the chip 5 is pressed into the chip fitting hole 10 from the rear end side. The joint 3 is made of an elastically deformable synthetic resin and is integrally formed. A valve chamber 13 is provided at the rear in communication with the tip fitting hole 10. Also, the valve chamber 13
The rear end is provided with a tapered or spherical ball receiving seat 14. A guide hole 20 communicating with the ball receiving seat 14 is formed behind the valve chamber 13, and a ball valve 15 is loosely fitted in the valve chamber 13. On the other hand, the tip 5 is swaged so that the tip ball 5a is rotatably held with the tip ball 5a substantially in contact with a seat having a channel 5b into which ink can flow. A spring 16 is urged into the inner hole of the chip 5. An upright bar shaft 17 is located at the end of the spring 16.
Is formed, and the tip of the rod shaft portion 17 is pressed against the rear end of the tip ball 5a. The tip ball 5a is brought into close contact with the inner edge of the ball holding portion (formed by caulking or the like) of the chip 5 by the pressing. A notch 19 is provided at a required position on the shaft side surface at the rear end of the shaft portion 11 of the chip, and the rear end is caulked so that the caulking portion 18 comes into contact with the rear end of the spring 16 and It is impossible to pull out. From the above,
When the tip side is downward, the ball valve 15 is
8 comes into contact with the rear end of the tip ball 5a through the guide hole 20, the notch 19, and the inner hole of the chip 5. A flange 21 is provided at the rear end of the locking cylinder 7 of the joint 3, and a fitting cylinder 12 is provided behind the flange 21.
Is extended. A cylindrical ink storage tube 4 is press-fitted and fixed to the outer periphery of the fitting cylindrical portion 12 with its front end abutting on the rear end of the flange portion 21.
It communicates with 0. The ink container 4 is filled with ink 22 having a low viscosity or a static viscosity having a high viscosity, and having a viscosity decreasing by the rotation of the ball during writing, and having a shear-thinning viscosity which allows the ink to flow out. Ink 22 if necessary
The rear end is filled with a grease-like follower that can move following the ink surface as the ink is consumed. or,
Further, a follower rod made of resin is loaded in the follower as needed. (Not shown) As described above, the refill of a ballpoint pen constituted by fixing the tip 5 and the ink containing tube 4 filled with ink to the joint 3 is inserted into the shaft cylinder 1, and The rear end edge of the flange portion 21 of the joint 3 was brought into contact with the front surface, and the base 2 provided with the step 9 on the inner surface thereof was brought into contact with the peripheral surface of the rib 8 of the joint 3. In this state, the ball-point pen is screwed onto the shaft portion 6 of the shaft cylinder 1. FIG. 3 shows a second embodiment of the present invention. Since it is basically the same as the first embodiment, only the differences will be described. The front end of the spring 32 inserted into the chip 5 forms a seat, and a push body 30 having a rod shaft portion 31 is disposed at the front portion thereof, and the front end of the rod shaft portion 31 is the rear end of the tip ball 5a. Abuts on the pressing member. First, FIG. 1 shows a state before writing with the tip 5 turned down, and at this time, the ball valve 15 is
Is brought into contact with the rear end, and the conducting hole 20 is opened. The ink 22 that has entered the valve chamber 13 from the ink storage tube 4 through the guide hole 20 flows into the inner hole of the chip from the notch 19 and is guided to the rear end of the tip ball 5a. In this state, the tip ball 5a is brought into close contact with the inner edge of the chip holding portion by the pressing of the rod shaft portion 17, so that the direct current of ink is prevented. Further, since the tip ball 5a is slightly retracted by the writing pressure, a gap is generated and the ink flows out to enable writing. FIG. 2 shows a state in which the tip 5 is directed upward. At this time, the ball valve 15 is in close contact with the ball receiving seat 14 of the valve chamber 13 to seal the guide hole 20. Even if the ink immediately below 5a runs out, the ink does not flow backward. Therefore, when the chip 5 is turned downward, the ink can immediately flow out, and the writing is prevented from being flared.
(By the way, in the structure without the ball valve, the close contact state of the tip ball is released by upward writing, a large ink head is applied, and the ink acts in the backward flow direction, so that air is easily entrapped in the chip. The ink does not immediately follow the ink, and the ink is not easily followed, so that the ink is apt to be rubbed, and air entrapment is accumulated by repeating the upward writing. The refill of the ballpoint pen according to the embodiment is mounted on the barrel 1 when the flange 21 of the joint 3 is attached to the shaft. The base 2 is screwed in contact with the front end of the base 6, and at this time, the rib 8 of the locking cylinder 7 bites against the step 9 of the base 2, so that the gap between the chip 5 and the base 2 is maintained. Mo [0015] The configuration and operation of the ballpoint pen of the present invention are as described above, and since the tip ball is in close contact with the inner edge of the chip holding portion except when writing, the writing blur is prevented. In addition, direct current is prevented when the ball is placed downward, and even if the tip ball is not in close contact, the backflow of ink due to impact such as upward writing or upward drop is caused by the ball valve that fits loosely into the valve chamber. It is possible to reliably prevent the occurrence of stains on the inside of the shaft cylinder, hands, clothes, etc. In addition, since ink can immediately follow after upward writing or impact, it is possible to prevent sharpness immediately after that. The ballpoint pen has an effect that the writing feel is good because the tip and the base are loosened through the joint.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a longitudinal sectional view of a main part of a ballpoint pen according to a first embodiment of the present invention, showing a state in which a chip is directed downward. FIG. 2 is a longitudinal sectional view of a main part of the ballpoint pen according to the first embodiment of the present invention, showing a state where a chip is directed upward; FIG. 3 is a vertical sectional view of a main part of a ballpoint pen according to a second embodiment of the present invention, showing a state where a chip is directed upward; DESCRIPTION OF SYMBOLS 1 Shaft cylinder 2 Cap 3 Joint 4 Ink storage tube 5 Tip 5 a Tip ball 5 b Channel 6 Shaft 7 Locking cylinder 8 Rib 9 Step 10 Chip fitting hole 11 Shaft 12 Fitting cylinder 13 Valve chamber 14 Ball seat 15 Ball valve 16 Spring 17 Bar shaft portion 18 Caulking portion 19 Notch 20 Guide hole 21 Flange portion 22 Ink 30 Press body 31 Bar shaft portion 32 Spring

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) B43K 1/08 B43K ^7/ 00-7/12

Claims (1)

(57) [Claims] [Claim 1] A ballpoint pen tip is attached to the tip of the joint,
The rear end has an ink storage tube, and the ink storage tube has a viscous
Low ink or high viscosity for static, tip for writing
Shears where the viscosity drops due to the rotation of the ball and ink flows out
Filled with ink with reduced viscosity and follows the trailing edge of ink
A follower is provided, and the shaft center of the joint communicates with the rear end of the chip, and a valve chamber is provided at the rear, and a tapered or spherical ball seat is provided at the rear of the valve chamber, and can be closely contacted with the ball seat. In a ball-point pen provided with a backflow prevention mechanism for ink in which a ball valve is loosely fitted in the valve chamber, a spring is biased in the chip inner hole, and the tip of the spring is rotatably held at the tip of the spring. By pressing the rear end of the held tip ball, the tip ball is brought into close contact with the inner edge of the ball holding portion of the chip, and is located on the shaft side surface at the rear end of the shaft portion of the chip.
Notches are provided at important points and the rear end is caulked,
The rear end of the spring cannot be pulled out at the caulked portion at the rear end of the tip.When the tip side is upward, the ball valve is in close contact with the ball receiving seat and the guide hole is sealed. A ballpoint pen, wherein the ball valve is configured to be released and a ball valve abut on a rear end of the chip so that ink flows into the inner hole of the chip through the guide hole and the cutout of the rear end of the chip.