JP2002103872A - Ball-point pen writing medium - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a ball-point pen writing medium of 0.5 mm-tip ball diameter type which is free from such a trouble that the tip ball does not come off even when the life of the pen is almost terminated and also shows improved writing performance and better drawn writing line width. SOLUTION: This ball-point pen writing medium is housed in a cap-off writing utensil and uses low-viscosity ink. In addition, the writing medium is of such a construction that the tip ball is always brought into close contact with the inner face of a ball embracing part of the tip by spring pressing. The diameter of the tip ball retained by the ball embracing part of the stainless steel tip is 0.53-0.55 mm and the dimension of the exposed part of the tip ball from the tip edge is set to be 30% of the diameter of the tip ball.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a ballpoint pen writing body using low-viscosity ink mounted on a writing instrument with a cap off, and a tip ball is pressed by a spring against the inner surface of a ball holding portion of a chip. Related to things that are always in close contact with each other.

[0002]

2. Description of the Related Art Conventionally, as shown in FIG. 1, a plurality of writing bodies fixed to a plurality of knock operation portions in a shaft cylinder are selectively slidable along vertical grooves provided in the shaft cylinder, respectively. Then, the tip of one writing body is made to protrude from the tip end of the barrel to engage, and each of them protrudes to release the engagement of the other writing body and to be stored in the barrel by the action of the return spring. 2. Description of the Related Art A slider-type double writing instrument such as a multicolor ballpoint pen is known. Also, a plurality of writing bodies having sliding pieces fixed to the rear end thereof are urged with a return spring between the guide cylinder and the sliding pieces, in the plurality of guide grooves of the guide cylinder provided in the shaft cylinder,
Cylindrical cams, each having a cam slope that is axially displaceable and that is fitted to be able to move back and forth in the axial direction, are provided so as to be rotatable and axially displaceable with respect to the guide cylinder, and each sliding piece contacts the cam slope. 2. Description of the Related Art There is known a rotary dual-purpose writing instrument in which the sliding piece is alternately moved back and forth by rotation of a cylindrical cam by being brought into contact with each other so that the tip of each writing body can be selectively protruded and retracted from a tip end of a front shaft. . (Not shown)

Further, as shown in FIG. 3, a tip portion of a writing pen of a ballpoint pen is rotated by pressing a knocking portion projecting from a rear end of a barrel to rotate a rotor in a cam portion in the barrel. 2. Description of the Related Art A knock-type writing instrument that can be locked in a protruding state and a stored state from a distal end of a cylinder is known. The above describes a writing implement that allows the tip end of a writing pen of a ballpoint pen to protrude and retract from the tip end of the barrel while the cap is off, and its structure is various and does not limit the gist of the present invention.

[0004] Further, conventionally known oil-based ballpoint pen inks have high viscosity, and have problems such as unevenness of writing, unevenness of writing lines, low density, and high writing pressure during writing. In addition, although it is a relatively low-viscosity ink as an improvement of the conventional oil-based ballpoint pen, it is filled with a water-based ink that has a so-called shear-thinning property. Known ballpoint pens are known. In such a ball-point pen, when writing upward, if the ink on the back side of the tip ball runs out, there is a danger that the hand or clothes will be stained due to a remarkable backflow due to the direct application of the ink head. In addition, since the viscosity of the ink is low and the amount of the ink flowing out is large, when the tip side faces downward and a gap is formed between the tip end ball and the ball holding portion of the chip, the ink bleeds (direct current).
That is, if the tip of the tip is in contact with the cloth, there is a problem that the ink is sucked out and the cloth is soiled. In addition, there is, of course, a problem that the writing tip becomes dry and writing becomes impossible. In addition, there is a problem that the ink on the back surface of the tip ball tends to flow backward after upward writing or after impact such as knocking or dropping, so that writing blur occurs. (The tip of the water-based ballpoint pen has a larger vertical play between the tip ball and the ball holding portion of the tip than the tip of the oil-based ballpoint pen.) Therefore, the ink is usually consumed at the rear end of the ink when writing. However, a grease-like follower is provided to suppress the backflow of the ink due to its own weight or impact. Means for pressing the back surface of the tip ball with a spring so that the tip ball is in close contact with the ball holding portion of the chip, and means for providing a valve chamber in which a ball valve is loosely fitted at the rear end of the tip are used.

On the other hand, a ballpoint pen made of low-viscosity oil-based ink has been considered as an improvement over the conventional ballpoint pen made of high-viscosity oil-based ink. When a low-viscosity oil-based ink is used, there is no problem of drying of the tip of the chip. In addition, the vertical play of the ball holding portion of the tip ball and the tip can be made smaller than that of the water-based ballpoint pen, which is advantageous for direct current of ink. or,
Tip ball diameter is 0.5mm or less (0.3mm, 0.4m
In the case of “m”, the outflow of ink is small and the ink flow path in the chip is narrow, which is advantageous for preventing direct current and backflow of ink. Further, the shorter the length of the ink containing tube (the length of filling of the ink) and the smaller the inner diameter of the ink containing tube, the more advantageous in preventing direct current and backflow of the ink.

[0006] Based on the above, by using a low-viscosity oil-based ink, the outer diameter of the ink storage tube is set to 3 to 3.5 mm, and the tip ball diameter is set to 0.5 mm or less. In addition, even if the backflow prevention mechanism is not provided, it is possible to provide a replacement core for a ball-point pen writing material for a double-type writing instrument that has a satisfactory use including the writing life. However, a ballpoint pen using a low-viscosity oil-based ink also has a tip ball diameter of 0.5 mm or more, and a means for preventing direct current or backflow of the ink as in the case of the above-mentioned aqueous ink when the ink storage tube is thick. Is this.

[0007] The above-mentioned ball-point pen writing material using an aqueous ink having a relatively low viscosity and a shear-thinning viscosity has a tip in which the tip ball is held when writing is continued until the ink is consumed (writing life). Because the inner surface of the ball holding part has a large vertical play between the tip ball and the tip ball holding part (compared to an oil-based ballpoint pen) and the ink contains a pigment, The ball is considerably worn, and the outer surface of the ball holding portion is worn by friction with the paper surface, so that the holding strength of the tip ball is significantly reduced. (Supplementary explanation is that, since writing is usually performed with respect to the paper surface, the ball holding portion of the chip is rubbed against the paper surface, and if the ball holding portion is thick, the writeability is significantly impaired. On the other hand, the ball holding section is designed to be as thin as possible.) Also, when low-viscosity oil-based ink is used, the vertical play between the tip ball and the chip holding section is small, Since the dye is often used, the holding strength of the tip ball is larger than that of the water-based ink. However, when the tip ball diameter is 0.5 mm or less (for fine characters of 0.3 mm and 0.4 mm), the holding strength is Not enough. Also,
When the diameter is 0.5 mm or more, the holding strength may not be sufficient because the back surface of the tip ball must be pressed by the spring.

[0008]

SUMMARY OF THE INVENTION The present invention relates to a ballpoint pen writing body using low-viscosity ink which is mounted on a writing instrument with a cap off, and a tip ball is pressed against the inner surface of a ball holding portion of a chip by a spring. It was designed to be always in close contact. As described above, the tip of the ball-point pen writing material whose writing life has expired has a state in which the holding strength of the tip ball is significantly reduced, and the tip ball is easily dropped. Moreover, the tip ball is pressed by a spring toward the pull-out side to enable the cap to be turned off. In addition, since the tip ball is left exposed, the ball is easily affected by a drop impact or the like. Further, in the case of a knock-type writing instrument, a knock impact frequently occurs. The drop of the tip ball has been further increased. Needless to say, if the tip ball falls off, not only writing becomes impossible, but also a problem that stains clothes and surroundings occurs. An object of the present invention is to make it possible to prevent the tip ball from falling off without impairing writability in such a situation.

Incidentally, in the cap-type writing instrument, the problem that the tip ball falls off can be ignored because the tip ball is held by the seal member such as rubber provided in the cap by pressing. In addition, a cap-type writing instrument using a low-viscosity ink has a tip ball diameter of 03 mm, 0.4 mm,
It is offered in thin, medium, and bold characters such as 0.5 mm, 07 mm, and 1.0 mm. The largest need is 0.5 mm.

[0010]

The present invention has the following arrangement to achieve the above object. The ballpoint pen writing body according to the invention according to claim 1 is a ballpoint pen writing body using a low-viscosity ink mounted on a writing instrument with a cap off, and the tip ball has a spring on the inner surface of the ball holding portion of the chip. The diameter of the tip ball held by the ball holding portion of the stainless steel tip is 0.53 to 0.55 mm in the one that is always in close contact by pressing,
The dimension of the tip ball protruding from the tip end face is set to 30% of the tip ball diameter.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS First, FIG. 1 shows a plurality of ballpoint pen writing bodies 3 fixed to two
Are slidable along the vertical grooves 1a provided in each of them, and the tip of one writing body is selectively made to protrude from the tip end of the barrel cylinder to engage with each other. It is a slider-type double writing instrument such as a multicolor ballpoint pen which is released and stored in the shaft cylinder by the action of the return spring 4.

A ball-point pen writing body 3 shown in FIG. 2 is a ball-point pen writing body filled with a low-viscosity oily or water-based ink having a shear-thinning viscosity, and has a format to be mounted on the above-described double-type writing instrument. . Further, as described above, it is important for the ballpoint pen writing body 3 to take measures to prevent the tip of the tip from being dried and to prevent direct current and backflow of the ink.

The structure of the ballpoint pen writing body 3 will be described. First, the tip 14 is rotatably held with the tip ball 15 substantially in contact with a seat having a channel through which ink can flow. Caulked. A spring 18 is inserted into the inner hole of the chip 14, the rear end of the shaft 16 of the chip is appropriately caulked, and the rear end of the spring 18 cannot be pulled out. In addition, a linear rod shaft portion 19 is formed in front of the spring 18,
The tip of the rod shaft portion is in contact with the rear end of the tip ball 15 in a pressing manner. The tip ball is brought into close contact with the inner edge of the ball holding portion of the chip 14 by the pressing.

A valve chamber 8, which is appropriately eccentric with respect to the axis of the tip 14, is provided behind the inner hole 13 of the joint 5, and a tapered or spherical shape is provided at the rear of the valve chamber so as to communicate with the guide hole 11. Ball receiving seat 9 is formed. A groove 10 through which ink can flow is formed on one side of the inner wall of the valve chamber 8, and a ball valve 12 is loosely fitted in the valve chamber. The guide hole 1 comes into contact with the rear end of the shaft portion 16 while being biased,
The ink flowing from 1 flows into the chip inner hole. The configurations of the ball valve and the valve chamber are not limited to the above.

A rear shaft 7 extends behind the front shaft 6 of the joint 5. A cylindrical ink storage tube 20 is fixed to the outer periphery of the rear shaft portion 7, and an inner hole of the ink storage tube 20 is electrically connected to the guide hole 11 of the joint 5. Also, ink storage tube 2
0 is filled with a low-viscosity oil-based ink with excellent drying resistance or a water-based ink 21 having a shear thinning property. A grease-like follower 22 is provided. In addition, as the ink storage tube 20, for example, a transparent PP resin molded product or the like is used. Also, the ball valve is not an essential element, and when the upward writing is frequently repeated, when the tip ball is incompletely close to the inner surface of the ball holding portion of the chip (the processing accuracy of the chip is poor, In this case, it acts as a double safety device to prevent the backflow of the ink when the solid content of the ink or the paper fiber is caught between the tip ball and the ball holding portion. For example, the outer diameter of the PP resin ink storage tube is small (3 to 3.
In the case of about 5 mm), it can be unnecessary. If the ball valve need not be provided, the joint is not always necessary, and the chip can be directly fixed to the ink container.

FIG. 3 shows a tip portion of a tip 27 of a ballpoint pen writing body 26 by pressing a knock portion 24 protruding from the rear end of a barrel 23 to rotate a rotor 25 within a cam portion in the barrel. 1 shows an example of a single-color knock-type writing instrument that can be locked in a protruding state and a stowed state from a tip end of a shaft cylinder.

The ball-point pen writing body 26 shown in FIG. 4 has a style mounted on a single-color knock-type writing instrument. Although the basic configuration is the same as that of the ballpoint pen writing body 3, the ink storage tube 29 is thickened, and a resin solid follower rod 32 is immersed inside the follower 31 so that the follower 31 is not deformed by an impact or the like. It becomes.

[0018]

FIGS. 6 and 7 show a chip 14 according to the present invention.
FIG. 4 is an enlarged view of a tip portion of FIG. In the figure, φA indicates the diameter of the tip ball 15 (tolerance ± 0.5 μ), and B indicates the dimension of the tip ball protruding from the end face of the chip 14. The tip is made of stainless steel, and the ballpoint pen writing material is filled with an aqueous ink having shear thinning properties. The pressing force of the spring pressing the back surface of the tip ball is 0.294 N (30 g max.).
f). In the writing test, “Mitsubishi Pencil” was written on a 500-character stuffed manuscript paper until the end of 1.1 g of ink (writing life), and then the load of the tip ball was measured.

(Conventional Example 1) When φA = 0.50 mm and B =
In the case of 0.150 mm (the leading dimension B of the tip ball is 30% of the tip ball diameter φA), the missing weight of the tip ball (indicated by the average value of N = 100P) The average missing weight of the sample before writing = 4.26N ( 434
gf) Weighted average value of samples after writing = 3.05 N (311
gf) Minimum value of missing weight of sample after writing = 1.31 N (134
gf) Writing line width: 0.48 mm (Conventional example 2) In the case of φA = 0.50 and B = 0.140 (tip ball protrusion dimension B is 28% of tip ball diameter φA), missing weight of sample before writing Average value = 4.47 N (456
gf) Weighted average value of the sample after writing = 3.39N (346)
gf) Minimum value of missing weight of sample after writing = 1.61 N (164)
gf) Writing line width: 0.49 mm

(Embodiment 1) φA = 0.53 and B = 0.1
59 (tip ball protrusion dimension B is 30 of tip ball diameter φA
%), The missing weighted average value of the sample before writing = 5.05N (515
gf) The missing weighted average value of the sample after writing = 3.64 N (371)
gf) Minimum value of missing weight of sample after writing = 1.83N (187)
gf) Writing line width: 0.50 mm (Example 2) In the case of φA = 0.55 and B = 0.165 (the protruding dimension B of the tip ball is 30% of the tip ball diameter φA), the missing weight of the sample before writing Average value = 5.58 N (569
gf) The missing weighted average value of the sample after writing = 4.02N (410
gf) Minimum value of missing weight of sample after writing = 2.09 N (213
gf) Writing line width: 0.52 mm

(Comparative Example 1) φA = 0.60 and B = 0.1
80 (tip ball protrusion dimension B is 30 of tip ball diameter φA)
%), The missing weighted average value of the sample before writing = 6.61N (674)
gf) The missing weighted average value of the sample after writing = 5.55N (566)
gf) Minimum value of missing weight of sample after writing = 3.15 N (321
gf) Writing line width: 0.56 mm

Further, a test is conducted by selecting from a lot of a sample group in which a measurement result is obtained, mounting the knocking type writing implement on knocking impact and dropping impact by repeated knocking operation.
If the weight of the tip ball coming out is 1.47 N (150 gf) or less, it is expected that the risk of the tip ball falling off is large.

[0023]

The construction of the present invention is as described above. A low-viscosity ink (water-based ink having a shear thinning property) is used for a writing instrument (knock type) with a cap off, and the tip ball is a ball holding portion of a chip. Press the spring on the inner surface of the
94N), when the ballpoint pen writing body is formed so as to be always in close contact with the ball, the conventional example 1 is in a danger zone where the weight of the tip ball after writing becomes 1.47 N (150 gf) or less, Not allowed. Further, Conventional Example 2 was improved to solve the problem of Conventional Example 1, and was slightly removed from the danger zone, so that even when the dimensions were slightly changed, the caulked edge on the outer surface of the ball holding portion was slightly more caught. Therefore, further improvement was desired because of poor writing performance.

In addition, the weight of the tip ball after writing in Examples 1 and 2 was sufficiently higher than 1.47 N (150 gf), and it was confirmed that there was almost no problem in writing properties and safety. In addition, it is preferable to use the second embodiment if consideration is given to use that is slightly more difficult than usual in terms of safety. The weight of the tip ball after writing in Comparative Example 1 was 3.15 N (321 gf), and it was naturally confirmed that the larger the tip ball diameter, the safer the ball. However, when the writing line width is 0.3, 0.
As can be understood from the fact that the journals are journalized at 4, 0.5, 0.7, 1.0 mm, etc., the fine writing line width affects the taste. By the way, 0.5m with the most needs
m, but as described above, the conventional writing line width is 0.1 mm.
The example was 0.50 to 0.52 at 48 to 0.49 mm, and the comparative example 1 was 0.56 mm at 48 to 0.49 mm. In addition, as a result of the taste survey, the hand-drawn line width of the example was such that the tip ball diameter was 0.4.
It was confirmed that there was no sense of incongruity as 0.5 mm, which was halfway between 0.7 mm and 0.7 mm. In Comparative Example 1, the recognition as 0.5 mm was impossible.

[0025]

The construction and operation of the present invention are as described above. The low-viscosity ink mounted on the writing instrument with the cap off is filled, and the tip ball is pressed against the inner surface of the ball holding portion of the chip by the spring. In a writing pen of a ballpoint pen having a tip ball diameter of 0.5 mm, which is formed so as to be always in close contact with each other, there is no problem of the tip ball falling off even at the end of writing, and the writing properties and the writing line width are improved.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing a slider-type compound writing instrument.

FIG. 2 is a vertical cross-sectional view of a style ballpoint pen writing body mounted on a double-type writing instrument.

FIG. 3 is a longitudinal sectional view showing a single-color knock type writing instrument.

FIG. 4 is a longitudinal sectional view of a ballpoint pen writing body mounted on a single-color knock type writing instrument.

FIG. 5 is an enlarged cross-sectional view showing a distal end portion of FIG. 4;

FIG. 6 is an enlarged view of a main part of the tip of the chip.

FIG. 7 is an enlarged view of a main part of the tip of the tip, and shows a state of being inclined when writing.

FIG. 8 is a sectional view showing a main part of the cap-type writing instrument.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Shaft cylinder 1a Longitudinal groove 2 Knock operation part 3 Ballpoint pen writing body 4 Return spring 5 Joint 6 Front shaft part 7 Rear shaft part 8 Valve room 9 Ball receiving seat 10 Groove part 11 Guide hole 12 Ball valve 13 Inner hole part 14 Chip 14a Ball Holder 15 Tip ball 16 Shaft 17 Caulking 18 Spring 19 Bar shaft 20 Ink storage tube 21 Ink 22 Follower 23 Shaft tube 24 Knock 25 Rotor 26 Ballpoint pen writing body 27 Chip 28 Joint 29 Ink storage tube 30 Ink 31 Follower 32 Follower stick

Claims (1)

[Claims] 1. A ballpoint pen writing body using a low-viscosity ink mounted on a writing instrument with a cap off, wherein a tip ball is always in close contact with an inner surface of a ball holding portion of a chip by pressing a spring. The diameter of the tip ball held by the stainless steel tip ball holding part is 0.53-0.55 mm, and the dimension of the tip ball protruding from the tip end face is set to 30% of the tip ball diameter. Ballpoint pen cursive.