JPS6139582Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to an ink guide part of a water-based ballpoint pen. In detail, it always provides stable and smooth ink flow, and prevents ink from leaving the writing tip facing upward, or when the product is subjected to impact, the ink on the back of the ball will drop back and become impossible to write on. The present invention relates to an ink guiding section of a water-based ballpoint pen that eliminates the conventional so-called "ink swallowing phenomenon" which causes poor tracking.

Conventionally, as a structure for supplying ink to the back of the ball held at the tip of the tip tube, a structure was formed between the linear body loosely inserted into the tip tube behind the ball receiving seat and the tip tube wall. There are many proposals for introducing ink from an ink reservoir using the gap as an ink passage, and some have been put into practical use. However, this type of water-based ballpoint pen has often been prone to defects due to the above-mentioned "ink swallowing phenomenon."

The present invention provides an effective and practical structure of an ink guiding part that improves the above-mentioned conventional deficiencies.

The present invention will be explained below with reference to the drawings. 1 and 4 illustrate longitudinal cross-sections of essential parts of the ink guiding section of the present invention, FIGS. 2 and 3 are those shown in FIG. 1, and FIGS. 5 and 6 are those shown in FIG. 4. each A-A
A cross-sectional view taken along line and line B-B is shown.

As illustrated in the vertical cross-sectional view, the ink guiding section of the present invention has a ball 5 rotatably held at the tip by using the upper surface of the reduced diameter section 2, which is obtained by pressing and deforming the vicinity of the tip of the metal cylindrical body 1, as a ball receiving surface 4. At the same time, a linear body 6 is loosely inserted in the axial direction at the back of the diameter reducing part 2, and an ink passage 7 is formed between it and the inner wall of the cylindrical body 1. A large number of micro grooves 8 communicate from the inner wall of the section to the rear end of the cylindrical body.
is provided on the inner wall of the cylindrical body.

In the above configuration, the ink storage section (drawing omitted)
The built-in ink is guided through the annular gap formed between the circumferential surface of the linear body 6 in the axial direction and the inner wall of the cylindrical body 1 as an ink passage 7, and through the ink passage hole 3 of the reduced diameter part 2. It is then supplied to the back of the ball. This structure provides ample ink for writing, making it practical. However, when the writing part is left facing upward, when a shock is applied to the product, or due to variations in component precision or processing precision, the "ink swallowing phenomenon" described at the beginning may occur.
Due to this, writing errors tended to occur. The present invention discloses an effective structure to improve this, and in addition to the above structure, a large number of micro grooves are provided which communicate from at least the inner wall of the reduced diameter part 2 to the rear end side of the cylindrical body 1. 8 is required to be provided on the inner wall of the cylindrical body 1.

As shown in the figure, each of the micro grooves described above is formed to communicate with the ink passage 7 and further with the ink passage hole 3. Here, the micro grooves 8 themselves have a capillary force, and are further formed to have a higher capillary force than the ink passage 7 and the ink passage hole 3. Furthermore, as described above, the micro grooves 8 extend from the rear end of the cylindrical body to at least the inner wall of the reduced diameter portion 2, which is close to the back surface of the ball, and this effectively functions to "prevent ink from being swallowed." This point will be explained below.

In conventional systems that do not have the micro grooves 8, if the writing tip is left facing upward or if an impact is applied to the product, the ink on the back of the ball will flow backward from the ink passage hole 3 and further from the ink passage 7. It is easy to drop back, and for this reason, at the time of writing, ink tracking is poor for a while, resulting in unclear handwriting, or defects that often result in the inability to write. This is because the capillary force of the ink passage hole 3 and the ink passage 7 connected thereto is relatively weak and does not have an ink retention force that can withstand the above conditions.

However, if we were to further reduce the gap between the ink passage hole 3 and the ink passage 7 connected to it to form a strong capillary force to ensure ink retention that withstands dropback, it would be necessary to When the amount of ink supplied tends to be insufficient, a linear object is loosely inserted into this type of chip cylinder, an ink passage is formed between it and the chip cylinder wall, and the ink passage is passed through the reduced diameter ink hole to the back of the ball. In the ink supply structure, it has been difficult to obtain a function that satisfies both ink retention and ink supply amount.

The present invention satisfies both of the above-mentioned functions by arranging micro-grooves configured as described above, and utilizes the strong capillary force of the micro-grooves to supply a sufficient amount of ink from the ink passages and ink holes. This is achieved by The fine grooves communicating with the ink passages and ink passage holes not only supply the ink retained by itself due to its strong capillary force, but also suppress the dropback of the ink in the ink passages and the through holes, and also reduce the tendency of ink to drop. It has the function of quickly restoring ink to a writable state.

It has already been disclosed in the past that tiny grooves are formed at positions on the inner wall of the tip tube corresponding to the insertion point of the linear body, but this invention provides an effective ink guide section in which tiny grooves are extended from the rear end edge of the tip tube even on the inner wall of the reduced diameter section close to the back surface of the ball, which directly affects ink intake, and in which the ball seat surface is formed integrally with the internal ink passage hole by forming the reduced diameter section.

The ink guiding section of the present invention having the above structure can be obtained as follows. A metal cylindrical body 1 is used, which is cut into an appropriate shape and size and has a large number of micro grooves 8 formed in advance in its inner wall. The micro grooves are formed by rolling a plate having a large number of grooves inward to form a pipe, by driving a broach into a cylindrical body, or by electric discharge machining or the like. . Next, a portion near the tip of the cylindrical body is pressed inward to form a reduced diameter portion, and an ink passage hole 3 is provided inside the reduced diameter portion, and a ball receiving surface 4 is provided on the upper surface of the reduced diameter portion. Here, the reduced diameter portion 2 can also be effectively formed by a plurality of inward protrusions formed by pressing and deforming substantially the same position of a cylindrical body from multiple directions as shown in FIGS. 4 and 5. The diameter reduction by the pressing process described above is performed with consideration given to not closing the minute groove extending from the rear end side of the cylindrical body. Here, since the diameter-reduced portion is made by narrowing the cylindrical body by pressing deformation as described above, it forms a narrower and stronger capillary gap compared to other parts of the cylindrical body. It is also possible to do so, which further enhances the effects of the present application.

The tip of the metal cylindrical body formed as described above rotatably holds the ball, and a linear body is loosely disposed behind the reduced diameter part to ink ink between it and the inner wall of the cylindrical body. The passage is formed to constitute the ink guide portion of the water-based ballpoint pen of the present application.

[Brief explanation of drawings]

1 and 4 are longitudinal sectional views of main parts of the present invention, and FIGS. 2 and 3 are A-A of FIG. 1, and FIGS. 5 and 6 are A-A of FIG. 4. line and B-B
It is a cross-sectional view of a line. 1...Metal cylindrical body, 2...Reduced diameter part, 2-1...
Inner wall of reduced diameter part, 3... Ink passage hole, 4... Ball receiving surface, 5... Ball, 6... Linear body, 7... Ink passage, 8... Micro groove.

Claims (1)

[Scope of utility model registration request] Ink is supplied to the back of the ball through the internal axis of the reduced diameter section, which is formed by pressing and deforming the vicinity of the tip of the metal cylindrical body.
An ink passage hole serving as a main passage is formed, and a ball is rotatably held at the tip as a ball receiving surface on the upper surface of the reduced diameter part, and a linear body is attached to the back of the reduced diameter part in the axial direction. In a water-based ballpoint pen that is inserted loosely and supplies ink from the ink storage section to the back surface of the ball by forming an ink passage with the wall of the cylindrical body, communication is provided from at least the inner wall of the reduced diameter section to the rear end side of the cylindrical body. has capillary force itself,
An ink guiding section of a water-based ballpoint pen, comprising a plurality of micro grooves in the axial direction, which are narrower than both the ink passage and the ink passage hole, provided in the inner wall of the cylindrical body.