JPH09226287A - Manufacture of ballpoint pen refill - Google Patents

Abstract

PROBLEM TO BE SOLVED: To effectively prevent the damage of a barrel or the mounting failure of the barrel by bringing the conical surface of a pressing pin into pressure contact with the inner peripheral edge of the opening of an ink containing tube obtained by cutting a pipe, and then press injecting and fixing the barrel to the inner surface of the opening of the tube. SOLUTION: A pressing pin 4 formed at the conical surface 41 of the end integrally with the base of metal material, and the outer diameter of the surface 41 is set to the size which can be brought into contact with the inner peripheral edge of an ink containing tube 2. The end of the pin 4 having the surface 41 is inserted into the opening of the tube 2 in the axial direction, and the surface 41 is circumferentially brought into pressure contact with the inner peripheral edge. Thus, the burr 3 of the inner peripheral edge of the tube 2 is bent to the tube 2, and the entire edge is collapsed to the conical surface state. Further, the end shape of the edge of the opening of the tube 2 is corrected to a suitable circular shape immediately after cutting by the pressure contact of the surface 41.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a ballpoint pen refill. More specifically, a pipe obtained by extrusion molding of synthetic resin is cut into an appropriate length to form an ink containing tube, and a chip holder made of synthetic resin or a tail plug made of synthetic resin is provided on the inner surface of the opening of the ink containing tube. The present invention relates to a method for manufacturing a ball-point pen refill in which the above materials are press-fitted and fixed.

[0002]

2. Description of the Related Art Conventionally, in this type of ball-point pen refill, for example, Japanese Utility Model Publication No. 6-23788 discloses a pipe body which is an extrusion molded product of a synthetic resin such as polyethylene or polypropylene, and an inner wall of the pipe body. A ball-point pen refill including a synthetic resin chip holder that is press-fitted and fixed is disclosed.

Further, Japanese Patent Laid-Open No. 7-299986 discloses that "a ball-point pen tip is provided at the tip for the purpose of reducing the pressure input between the tip holder and the ink containing tube and suppressing scraping or cracking of the fitting portion. In a water-based ballpoint pen in which a holder is fitted to the front part of an ink containing tube capable of directly containing the aqueous ink, after applying a lubricant to at least one of the fitting part of the holder and the fitting part of the ink containing tube, the holder And a method of manufacturing a water-based ballpoint pen in which an ink containing tube is fitted. "

However, conventionally, in this type of ball-point pen refill, as shown in FIGS. 9 and 10, the ink containing tube 8 is formed by appropriately cutting a cylindrical pipe made of a synthetic resin extruded product. This is a configuration, and burrs 83 (that is, return burrs) tend to be generated in the radial direction at the edge portion (that is, the corner end portion) of the pipe due to the cutting. In particular, when the burr 83 is generated on the inner circumference of the edge portion of the pipe, the pressure input when the cylinder body (that is, the tail plug 81, the tip holder 82) is press-fitted must be increased, resulting in incomplete mounting. There is a risk that the cylinder fitting portions 81a and 82a made of synthetic resin may be damaged. This easily occurs when the material of the cylinder is softer than the material of the ink containing tube. The cylindrical fitting portion 81a,
If there is a damaged portion on 82a, there is a possibility that ink may leak from the fitting portion of the tip holder after the press-fitting fixation and leakage of the backflow preventive agent from the tail plug fitting portion after the press-fitting fixation. Furthermore, when the ink containing tube 8 is transparent or semi-transparent, the cylindrical fitting portions 81a and 82a appear to be dirty due to the damaged portion, and the appearance thereof may be impaired.

Certainly, in the manufacturing method disclosed in Japanese Patent Laid-Open No. 7-299986, in which the lubricant is applied to the fitting portion, even if the pressure input at the time of press-fitting the cylinder is reduced,
When the burr generated at the inner peripheral edge of the pipe after cutting was large, the application of the lubricant was not sufficient, and the cylinder could not be smoothly pressed into the ink containing tube with a small press force.

[0006]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems of the prior art. It is possible to smoothly press fit and fix a cylinder such as a tip holder or a tail plug into an ink containing tube. An object of the present invention is to provide a method of manufacturing a ball-point pen refill that reliably prevents body damage and defective attachment of a cylindrical body.

[0007]

Means for Solving the Problems Outline The present invention provides a pipe 1 obtained by extrusion molding of a synthetic resin.
Is cut into an appropriate length to form an ink containing tube 2, and a method for manufacturing a ball-point pen refill in which synthetic resin cylinders 5 and 6 are press-fitted and fixed to the inner surface of the opening of the ink containing tube 2, and the pipe 1 is cut. The conical surface 41 of the pressing pin 4 is pressed against the inner peripheral edge of the opening of the ink containing tube 2 obtained as described above, and then the cylinders 5 and 6 are press-fitted and fixed to the inner surface of the opening of the ink containing tube 2. Is the gist. (See FIGS. 1 to 7)

Further, according to the present invention, a pipe 1 obtained by extrusion molding of a synthetic resin is cut into an appropriate length to form an ink containing tube 2, and a cylindrical body 5 made of synthetic resin is formed on the inner surface of the opening of the ink containing tube 2. , 6 is a method for manufacturing a ball-point pen refill in which press-fitting is performed, and the ink containing tube 2 is obtained by cutting the pipe 1.
By pressing the conical surface 41 of the pressing pin 4 against the inner peripheral edge portion of the ink, the burr 3 formed on the inner peripheral edge portion of the ink containing tube 2 is bent into the ink containing tube 2, and then the ink containing tube 2 The gist is to press-fit and fix the cylindrical bodies 5 and 6 on the inner surface of the opening. (See FIGS. 1 to 7)

Cylinders Cylinders 5 and 6 are cylindrical members having cylindrical fitting portions 52 and 62 and having a through hole therein, and include, for example, polypropylene, polyethylene, polyacetal, ABS resin,
Injection molded articles of synthetic resin such as polybutylene terephthalate are preferred. Specific examples of the tubular body include a tip holder 5 and a tail plug 6.

The tip holder 5 has a tip mounting portion 53 for holding a metal ball-point pen tip 54 having a ball rotatably held at its tip and a cylindrical shape press-fitted and fixed to the inner surface of the opening of the ink containing tube 2. A synthetic resin injection-molded body in which the fitting portion 52 and the fitting portion 52 are integrally connected in the front and back with the flange portion 51 interposed therebetween is effective.

The tail plug 6 is provided with a cylindrical fitting portion 62 press-fitted and fixed to the inner surface of the opening of the ink containing tube 2, and is integrally connected to the fitting portion 62, and is attached to the end surface of the ink containing tube 2. A synthetic resin injection-molded body composed of a flange portion 61 that can come into contact is effective. Further, the tail plug 6 has a vent hole 63 penetrating the axial center thereof.

The tip holder 5 and the tail plug 6 are
After attachment to the ink containing tube 2, the flange portions 51 and 61 are exposed to the outside. By coloring the collar portions 51 and 61 with an ink color, the ink color of the ink 21 contained in the ink containing tube 2 can be identified and displayed.

As the pipe 1 which becomes the ink containing pipe 2 by cutting the pipe, a straight cylindrical extruded body of synthetic resin such as polypropylene or polyethylene is effective. Further, when the pipe 1 is the ink containing pipe 2, the ink 21 inside
In order to make it visible from the outside, it is preferable to employ a transparent or translucent synthetic resin.

Pressing Pin Angle θ of the conical surface 41 (that is, conical outer peripheral surface) of the pressing pin 4
Is effective at 10 to 45 degrees. Because, when the angle θ is smaller than 10 degrees, the conical surface 41 of the pressing pin 4 becomes
Excessive biting on the inner peripheral edge of the ink containing tube 2 causes the inner diameter of the opening to be widened, whereby proper press-fitting and fixing of the cylinders 5 and 6 cannot be performed, or the pressing pin 4 after the press-contacting step. Make it difficult to extract. On the other hand, the angle θ is 4
If the angle is larger than 5 degrees, the bending angle (bending amount) of the burr 3 becomes insufficient, and problems due to the burr 3 (such as defective mounting of the tubular body and damage to the fitting portions 52 and 62 of the tubular body) cannot be eliminated. Further, the angle θ of the conical surface 41 is 15 degrees to 3 degrees.
It is preferably 5 degrees, and within that range, the conical surface 41 almost does not bite the inner peripheral edge of the ink containing tube 2,
Moreover, the troubles caused by the burr 3 can be reliably eliminated. Also,
The material of the pressing pin 4 (including the conical surface 41) is preferably harder than the ink containing tube 2 from the viewpoint of strength, and a metal material is actually used.

[0015]

The burrs formed on the inner peripheral edge of the ink containing tube 2 by pressing the conical surface 41 of the pressing pin 4 against the inner peripheral edge of the opening of the ink containing tube 2 obtained by cutting the pipe 1. 3 is bent and deformed into the ink containing tube 2,
The entire inner peripheral edge portion is deformed into a conical surface shape. This enables smooth press-fitting of the cylinders 5, 6 into the inner surface of the opening of the ink containing tube 2 without catching the cylinders 5, 6.
Can be prevented from being incompletely attached, and the fitting portions 52 and 62 of the tubular bodies 5 and 6 can be prevented from being damaged. In addition, the burr removal work such as time-consuming cutting is unnecessary. In addition, even if the fitting force between the cylinders 5 and 6 and the inner surface of the ink containing tube 2 is loosened due to aging, the burr 3 that has been bent and deformed has the cylinder 5 with respect to the falling direction of the cylinders 5 and 6. Since they bite into the fitting portions 52 and 62 of 6 and 6, they are effectively prevented from falling off.

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, specific embodiments of the present invention will be described with reference to the drawings.

1 to 7 show a method of manufacturing a ballpoint pen refill according to the present invention. FIG. 1 shows a pipe cutting process and a pressing pin pressing process, and the process proceeds from (A) to (D) in order.
(A) when cutting the pipe, (B) immediately after cutting the pipe,
(C) shows the pressure pin pressure contact, and (D) shows immediately after the pressure pin pressure contact. 2 is an enlarged view of B portion of FIG. 1B, and FIG. 3 is an enlarged external view of the end surface of the ink containing tube 2 of FIG. 1B.
FIG. 4 is an enlarged view of portion C of FIG. 1 (C), and FIG. 5 is D of FIG. 1 (D).
It is a part enlarged view. Further, FIG. 6 shows the step of press-fitting the tail plug 6, and FIG. 7 shows the step of press-fitting the tip holder 5.

Pipe cutting process [(A) of FIG. 1-
(B), FIGS. 2 and 3] The ink containing tube 2 is formed by pressing (cutting) a cylindrical pipe 1, which is an extruded product of translucent polypropylene resin, to a proper length in a radial direction with a thin blade cutter 9. can get. The ink containing tube 2 is actually 88 m long.
m, inner diameter: 4.4 mm, and outer diameter: 6.0 mm. Further, as shown in FIGS. 2 and 3, burrs 3 and scratches are formed on the end surface of the ink containing tube 2 immediately after the cutting process in the direction in which the blade (cutter 9) moved during cutting.

Pressing pin pressing step [(C) of FIG.
(D), FIG. 4 and FIG. 5] The pressing pin 4 is formed by integrally forming a conical surface 41 at the tip end portion and a base portion connected to the conical surface 41 by a metal material. The outer diameter of the conical surface 41 is set so that it can contact the inner peripheral edge portion of the ink containing tube 2. That is, the conical surface 41 is provided with an angle θ (specifically 25 degrees) formed by connecting an outer diameter portion larger than the inner diameter of the ink containing tube 2 to an outer diameter portion smaller than the inner diameter of the ink containing tube 2. The tip of the pressing pin 4 having the conical surface 41 is axially inserted into the opening of the ink containing tube 2 to press the conical surface 41 circumferentially against the inner peripheral edge. As a result, the burr 3 at the inner peripheral edge portion of the ink containing tube 2 is bent into the ink containing tube 2, and the entire inner peripheral edge portion is crushed into a conical surface shape. Further, the pressure contact of the conical surface 41 corrects the end surface shape of the inner peripheral edge portion of the opening of the ink containing tube 2 from the non-circular shape immediately after cutting to an appropriate circular shape.

In the step of pressing the pressing pin 4, the pressing pin 4 presses the inner peripheral edge portion of the ink containing tube 2 in the axial direction.
The pushing force of the (conical surface 41) is a small force such that the outer peripheral edge portion of the ink containing tube 2 is not expanded and deformed outward, for example, 1
About 3 kilograms is suitable.

Cylindrical body mounting step (FIGS. 6 and 7) a) Tail plug mounting step (FIG. 6) The tail plug 6 is made of an injection molded body of polyethylene resin (a softer material than the ink containing tube 2). The tail plug 6 is composed of a cylindrical fitting portion 62 having an annular convex portion, and a collar portion 61 integrally connected to the fitting portion 62. In the mounting process [FIGS. 6 (E) to (F)], the fitting portion 62 (annular convex portion) rides over the inner peripheral edge portion of the opening of the ink containing tube 2 which is deformed into a conical surface, and the ink is contained. It is smoothly pressed into the inner peripheral surface of the opening of the pipe 2 without being caught. as a result,
The fitting portion 62 is liquid-tightly fitted to the inner peripheral surface of the ink containing tube 2 without damage.

The tail plug 6 has a vent hole 63 penetrating the axis thereof, and the vent hole 63 communicates the inside of the ink containing tube 2 with the outside air. The tip of the fitting portion 62 of the tail plug 6 is reduced in diameter, so that an annular space 23 is formed between the tail plug 6 and the inner peripheral surface of the ink containing tube 2. The annular space 23 receives the backflow preventive agent 22 when it flows out to the tail plug side, and prevents the backflow preventive agent 22 from leaking from the tail end portion of the ink containing tube 2.

B) Tip holder attaching step (FIG. 7) The tip holder 5 is a cylindrical body having a through hole in its axis, and a tip attaching portion 53 into which a metal ball-point pen tip 54 is press-fitted and fixed, and the tip attaching portion. A flange portion 51 that is connected to the portion 53 and is in contact with the end surface of the ink containing tube 2, and a cylindrical fitting portion 52 that is connected to the flange portion 51 and that fits with the inner surface of the opening of the ink containing tube 2. , Polypropylene (a softer material than the ink containing tube 2) is integrally formed by injection molding. The ball-point pen tip 54 has a ball receiving seat and a ball holding edge formed by inward plastic deformation at the tip of the metal pipe 1 made of stainless steel or the like, by which the ball is rotatably held at the tip. It is a configuration. In the mounting process [FIGS. 7 (E) to (F)], the fitting portion 52 of the chip holder 5 rides over the inner peripheral edge portion of the opening of the ink containing tube 2 which is deformed into a conical surface shape, and the ink containing tube. It is smoothly pressed into the inner peripheral surface of the second opening with a small pushing force.
As a result, the fitting portion 52 is not damaged and is liquid-tightly fitted to the inner peripheral surface of the ink containing tube 2.

In this embodiment, the ballpoint pen tip 54
However, the ball receiving seat is formed by inward deformation of the metal material. However, in addition to this, the ball receiving seat may be formed by cutting the metal material.

(Pushing Force) The pushing force when press-fitting the tail plug 6 and the tip holder 5 into the ink containing tube 2 is 9 kg and 14 kg, respectively, in the conventional manufacturing method which does not involve the pressing step of the pressing pin 4. On the other hand, in the manufacturing method of the present invention including the press contacting step of the pressing pin 4, the pressing force is reduced to 2 kg and 6 kg, respectively.
Smooth press-fitting and mounting work became possible without damage due to burr of 2,62.

FIG. 8 shows a ballpoint pen refill 7 obtained from the above embodiment (FIGS. 1 to 7). A water-based or oil-based ink 21 is directly stored in the semitransparent ink storage tube 2, and a grease-like backflow preventive agent 22 that moves toward the pen tip with ink consumption is provided at the rear end of the ink 21. Is filled. The ink 21 may be any one of low-viscosity or medium-viscosity ink 21, ink having shear thinning viscosity, and the like. Also, the tip holder 5 and the tail plug 6 are
Since the fitting portions 52 and 62 are not damaged by the burr 3,
The desired appearance can be maintained without impairing the appearance of the fitting portions 52 and 62 in the semitransparent ink containing tube 2.

When the ballpoint pen refill 7 is used,
The main body is housed in the barrel in a replaceable manner, and only the ballpoint pen tip 54 is projected from the tip. The shaft cylinder is of a type having a pen tip payout mechanism (for example, one for rotating the shaft cylinder, one for pressing the rear end surface or the side surface of the shaft cylinder, etc.), or the above-mentioned payout mechanism, An example is a type that allows immediate writing after removing the cap.

[0028]

According to the method for manufacturing a ballpoint pen refill of the present invention, even if burrs are generated at the inner peripheral edge of the opening of the ink containing tube obtained by cutting the pipe by the above method,
A cylinder such as a tip holder or a tail plug can be smoothly press-fitted and fixed to the ink containing pipe, and damage to the cylinder and incomplete mounting of the cylinder can be reliably prevented.

[Brief description of drawings]

FIG. 1 is an explanatory view of a pipe cutting process and a pressing pin pressure welding process according to an embodiment of the present invention.

FIG. 2 is an enlarged view of part B in FIG.

FIG. 3 is an enlarged external view of a pipe end surface immediately after cutting in FIG.

FIG. 4 is an enlarged view of a C portion of FIG.

FIG. 5 is an enlarged view of a D portion of FIG.

FIG. 6 is an explanatory diagram of a tail plug press-fitting step of the embodiment of the present invention.

FIG. 7 is an explanatory diagram of a press-fitting process of the chip holder according to the embodiment of the present invention.

FIG. 8 is a vertical sectional view of a ballpoint pen refill obtained from the present invention.

FIG. 9 is an explanatory diagram when a tail plug is press-fitted in the related art.

FIG. 10 is an explanatory diagram when a conventional chip holder is press-fitted.

[Explanation of symbols]

 1 Pipe 2 Ink Storage Tube 21 Ink 22 Backflow Preventing Agent 23 Annular Space 3 Burr 4 Pressing Pin 41 Cone Surface 5 Chip Holder 51 Collar Part 52 Fitting Part 53 Tip Mounting Part 54 Ballpoint Pen Chip 6 Tail Plug 61 Collar Part 62 Fitting Part 63 Vent hole 7 Ballpoint pen refill 8 Ink storage tube 81 Tail plug 81a Fitting part 82 Chip holder 82a Fitting part 83 Burr 9 Cutter

Claims (4)

[Claims] 1. A pipe (1) obtained by extrusion molding of synthetic resin is cut into an appropriate length to form an ink containing pipe (2),
A method for manufacturing a ball-point pen refill in which a cylindrical body (5, 6) made of synthetic resin is press-fitted and fixed to the inner surface of the opening of the ink containing tube (2), the ink containing tube obtained by cutting the pipe (1) ( The conical surface (41) of the pressing pin (4) is brought into pressure contact with the inner peripheral edge of the opening of (2), and then the cylindrical body (5, 6) is press-fit into the inner surface of the opening of the ink containing tube (2). A method of manufacturing a ball-point pen refill that sticks. 2. A pipe (1) obtained by extrusion molding of synthetic resin is cut into an appropriate length to form an ink containing pipe (2),
A method for manufacturing a ball-point pen refill in which a cylindrical body (5, 6) made of synthetic resin is press-fitted and fixed to the inner surface of the opening of the ink containing tube (2), the ink containing tube obtained by cutting the pipe (1) ( By pressing the conical surface (41) of the pressing pin (4) against the inner peripheral edge of the opening of (2), the burr (3) generated at the inner peripheral edge of the ink containing tube (2) is contained. A method of manufacturing a ball-point pen refill, which comprises bending a tube (2) into a tube (2), and then press-fitting and fixing a cylinder (5, 6) on the inner surface of the opening of the ink containing tube (2). 3. A tip holder (5) made of synthetic resin, wherein a cylindrical body has a metal ball-point pen tip (54) having a ball rotatably held at its tip and fixed to a front portion thereof. Ballpoint pen refill manufacturing method. 4. The method of manufacturing a ball-point pen refill according to claim 1, wherein the tubular body is a tail plug (6) made of synthetic resin.