JPS6141760B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a method for forming the tip of a synthetic resin barrel of a felt-tip pen into a conical tip, and at the same time forming a short base of a synthetic fiber tip on the inner wall of the tip of the tip. The present invention relates to a manufacturing method for mass-producing this type of felt-tip pen, which is made by welding, with high efficiency and low cost.

That is, as shown in the drawings of the embodiment, the inner shape is approximately conical, and the insertion hole H is formed on the center axis of the thick inner base.
A mold A with a shaft tip is provided, and the tip of a thin and short pen nib 2 made of bundled synthetic fibers is inserted into the insertion hole in the mold, and on the internal axis of the mold. After temporarily installing a synthetic resin shaft cylinder 1 cut to a predetermined length, the mold is energized and when the mold heats up to 200°C, the tip of the shaft cylinder is press-fitted into the mold. In a short period of time, the tip of the barrel is formed into a substantially conical tip portion 1', and at the same time, an in-mold protrusion near the middle of the pen tip 2 is formed on the inner wall of the tip hole. It can be melted. Therefore, the barrel 1 is removed from the mold 4, and a thick and long ink-retaining rod 3 made of a coarse bundle of synthetic fibers is inserted from the rear end of the barrel and brought into contact with the inner end of the pen tip. This is then obtained by fitting the tail plug 5 to the rear end of the shaft cylinder 1 using a conventional method.

Most conventional felt-tip pens with a nib of this type have a conical nib by first press-fitting the tip of a synthetic resin barrel that has been cut to a predetermined length into an internal conical heat retention mold. Next, a thin and short nib made of synthetic fibers is applied to the tip opening of the shaft tip part and inserted into the shaft, and then the synthetic fibers are soaked with ink from the rear end of the shaft cylinder. After inserting the rod, the rear end of the barrel is sealed tightly, or a short, conical or other holder with a pen tip inserted in advance is provided, and the holder is fitted onto the tip of the barrel. Thereafter, in most cases, an ink-retaining rod is inserted from the rear end of the barrel as described above, and then the rear end of the barrel is tightly plugged.

However, in the former method, a barrel with a tip is formed at the tip of the barrel in advance, and then small pen nibs are inserted one by one into the hole in the tip of the barrel. Not only does the molding process and the insertion of the nib require troublesome steps, but since most of the insertion is done using a solvent, there is a risk that the nib may come off or get stuck in due to writing pressure, and the latter also requires a holder. Since the holder is connected to the barrel after the pen nib is inserted into the component, it takes time and effort to assemble the components, which has the disadvantage of not being able to manufacture efficiently and of producing defective products. It also has the following characteristics.

However, according to the present invention, as described above, the tip of the synthetic resin barrel, which has been cut to a predetermined length, is made into a substantially conical inner shape, and the pen tip is inserted into the insertion hole provided on the center axis of the thick inner base. When the heat retention mold supporting the tip of the pen is inserted, a conical tip is formed and at the same time a part of the tip is welded to the inner wall of the tip opening of the tip. This eliminates the hassle of forming a pen shaft and attaching a pen nib, which is the conventional method of preparing a barrel with a nib in advance and then inserting the nib one by one into the hole with the nib. Furthermore, there is no need for parts or disadvantages in installation, such as those for connecting a holder with a pen tip to a barrel, and it is an optimal and simple method for mass-producing this type of felt-tip pens with high efficiency and low cost. This is an extremely useful invention.

[Brief explanation of the drawing]

The figures are examples, and Figure 1 is a side view showing the manufacturing process of a felt-tip pen by longitudinally cross-sectioning the tip end of the barrel tip die and the barrel barrel in this method, and Figure 2 is a side view showing the manufacturing process of a felt-tip pen obtained by this method. FIG. 2 is an enlarged side view showing a main part of the felt-tip pen in a vertically cutaway manner. 1 is the barrel, 1' is the barrel tip, 2 is the pen tip, 3
is a seepage-containing rod, 4 is a mold with a shaft tip, 5 is a seal plug, and H is a hole insertion hole.

Claims (1)

[Claims] 1. A shaft-end mold with a substantially conical inner shape and a hole drilled on the center axis of the thick inner inner base is provided, and a small pen made of a bundle of synthetic fibers is inserted into the hole in the mold. When the die is energized and heated, the tip of the synthetic resin barrel is inserted and the tip of the barrel made of synthetic resin is placed on the inner axis of the die. At the same time, the middle part of the pen nib is welded to the conical shaft tip, and then the barrel is removed from the mold and an ink-retaining rod is inserted from the rear end. A method for manufacturing a felt-tip pen, characterized in that the tip thereof is brought into contact with the inner end of the pen nib, and the rear end of the rear barrel is hermetically sealed.