JP7042556B2 - Stationery - Google Patents

Description

The present invention relates to a writing instrument having a writing core capable of inducing and retaining ink supplied from a writing instrument shaft, and more particularly, a writing instrument of a type generally called a paint marker, an oil-based marker, a water-based marker, or an underline marker. Regarding.

Conventionally, writing instruments called paint markers, underline markers, etc. are widely used because they are provided with a wide writing core to enable wide line drawing and have excellent marking visibility and workability. Has been done.
The writing core of a writing instrument such as a line marker is generally a rod-shaped bundle of synthetic resin fibers or the like, or a shaft body that is a writing instrument body by imparting a capillary action to a porous member such as a polymer sintered body. Writing is possible by deriving the ink supplied from the pen tip to the pen tip.

In addition, with the spread of writing instruments in which fluorescent ink is housed in the shaft body, which is the main body of the writing instrument, writing instruments with many structures and shapes that enable wide line drawing have become commercially available, making them suitable for users. It is possible to select a wide range of writing instruments according to the situation, and the workability is also comfortable.

The present applicant discloses a writing instrument having a writing core that can guide and hold ink supplied from a shaft body that is the main body of the writing instrument, and that has a visible portion (window) at the pen tip that allows the writing direction to be visually recognized. (For example, see Patent Document 1).
With this type of writing tool, you can see the written characters from the visible part (window) of the pen tip, so you can draw a line only where you want to check without sticking out. Specifically, as shown in FIG. 5A, ink is stored in the ink storage body 1a in the shaft body 1 which is the main body of the writing tool, and the pen body 2 and the other end, which are made of a fine writing core, are stored at one end. It has a pen body 3 made of a bold type writing core, and is configured to supply the ink of the ink storage body 1a to the pen body 2 and the pen body 3, respectively. The reference numerals 1b and 1c in the figure are caps that protect the pen body 2 and the pen body 3. Further, a pen body 3 made of a bold type writing core shown in FIG. 5B is attached to the rear shaft 4. As shown in FIG. 5B, the pen body 3 has ink guiding portions 3b and 3b and writing portions 3c made of substantially U-shaped porous members on the outer periphery of the holding body 3a which is a transparent supporting member. A writing core with is attached.

Further, in Patent Document 2 by the present applicant, as shown in FIGS. 6A and 6B, the ink contained in the writing instrument main body 5 is attached to the toe shaft 6 fixed to the writing instrument main body 5 and the toe shaft 6. A writing instrument for writing with a writing core 8 via an attached holder 7 is disclosed.

However, in the writing instruments disclosed in Patent Document 1 and Patent Document 2, if writing is continued with a strong writing pressure, an excessive load is maintained on the writing core, which causes a problem that the durability and writing performance of the writing core are impaired. Therefore, further improvement and improvement of the durability of the writing core are desired without impairing the writing performance.

JP-A-2000-52682 (Claims, paragraph 0014, FIG. 7, FIG. 24, FIG. 25) Japanese Unexamined Patent Publication No. 2014-50967 (Fig. 1 etc.)

The present invention is intended to solve this problem in view of the above-mentioned conventional problems, and even if writing is performed with a strong writing load, the durability of the writing core can be further improved without impairing the writing performance. The purpose is to provide writing instruments.

As a result of diligent studies to solve the above-mentioned conventional problems, the present inventor has written from a holding body in a writing instrument in which a writing unit is composed of at least a writing core made of a porous body and a holding body made of a hard material. It was found that the writing instrument of the above-mentioned object can be obtained by the configuration in which the strength on the tip side of the core is set to a specific value or more, and the present invention has been completed.

That is, the writing instrument of the present invention is a writing instrument in which the writing portion is composed of at least a writing core made of a porous body and a holding body holding the writing core, and the shear strength of the writing core is 5N or more. preferable.
It is preferable that the shear strength of the writing core is within 0.6 mm in length from the end face on the tip side of the writing core to the inside side.
It is preferable that the writing core is made of a sintered body obtained by sintering at least granular thermoplastic resin.

According to the present invention, there is provided a writing instrument having excellent durability that can prevent damage to the writing core without impairing the writing performance even when writing with a strong writing load.

(A) to (c) show an example of the writing instrument of this invention, (a) is a vertical sectional view, (b) is a front view, (c) is a rear view. (A) to (f) are drawings showing an example of a holding body that holds a writing core in the writing tool of FIG. 1, (a) is a plan view, (b) is a front view, and (c) is a vertical section. A plan view, (d) is a left side view, (e) is a right side view, and (f) is a central cross-sectional view. (A) to (f) are drawings showing an example of a state in which a writing core is attached to the holding body of FIG. 2, (a) is a plan view, (b) is a front view, and (c) is a vertical cross section. (D) is a left side view, (e) is a right side view, and (f) is a central cross-sectional view. (A) to (d) are explanatory views for measuring the shear strength of a writing core, and (a) is a left side view, a front view, and a right side view showing an example of a writing core to be measured. (B) to (d) are explanatory views showing the measurement process of the shear strength of the writing core. An example of a conventional writing instrument is shown, (a) is a vertical sectional view, and (b) is a partial front view showing a state in which a writing core is attached to a holding body. It shows another example of the conventional writing instrument, (a) is a perspective view seen from the front side, (b) is a perspective view seen from the rear side.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
1 to 3 show each drawing showing an example of an embodiment of the writing instrument of the present invention, each drawing showing an example of a holding body holding a writing core, and an example of a state in which the writing core is attached to the holding body. Each drawing. 4 (a) to 4 (d) are explanatory views for measuring the shear strength of the writing core, and (a) is each drawing showing an example of the writing core to be measured, (b). ~ (D) is each explanatory diagram which shows the measurement process of the shear strength of a writing core.
As shown in FIGS. 1A to 1C, the writing tool A of the present embodiment includes a shaft body (shaft cylinder) 10, an ink occlusion body 20, a writing core 30, a holding body 40, and a cap 50, which are the writing tool main bodies. I have.

The shaft body 10 is formed of, for example, a thermoplastic resin, a thermosetting resin, or the like, and as shown in FIG. 1A, a bottomed cylinder accommodating an ink occlusion body 20 impregnated with ink for writing tools. It has a rear shaft 11 in the shape of a pen and a toe shaft 15 to which a holding body 40 to which a writing core 30 serving as a pen tip is attached is fixed.
The rear shaft 11 is formed into a bottomed cylinder shape using, for example, a resin made of polypropylene (PP) or the like, and functions as a main body (shaft body) of a writing tool. As shown in FIG. 1A, the rear shaft 11 is provided with a holding member 13 including holding pieces 12, 12 ... For holding the rear end portion of the ink storage body 20 inside the rear end side. The entire shaft and the toe shaft described later are molded to be opaque or transparent (and translucent), but any of them may be adopted from the viewpoint of appearance and practical use. Further, the front shaft 15 is fixed to the front side of the rear shaft 11 by fitting or the like. When the ink for writing tools is a heat-discolorable ink, it is preferable to form a thermoplastic elastomer on the outer surface or the rear end portion of the rear shaft 11 to form a shaft body that easily generates frictional heat by scraping operation. ..
The toe shaft 15 is provided with a convex fitting portion 16 for fixing the main body portion 41 of the holding body 40 for fixing the writing core 30, which will be described later. The toe shaft 15 having this structure is formed of, for example, a resin made of polypropylene (PP) or the like.

The ink storage body 20 is impregnated with ink for writing tools such as water-based ink, oil-based ink, and heat-discolorable ink, and is, for example, natural fiber, animal hair fiber, polyacetal resin, acrylic resin, polyester resin, and polyamide. Fiber bundles made of one or more combinations of one or more kinds of resins such as resins, polyurethane resins, polyolefin resins, polyvinyl resins, polycarbonate resins, polyether resins, and polyphenylene resins, and fiber bundles such as felts were processed. It also contains porous materials such as sponges, resin particles, and sintered bodies. The ink storage body 20 is housed and held in the rear shaft 11 which is the main body of the shaft body 10.
Further, the ink composition to be used is not particularly limited, and a suitable compounding formulation such as water-based ink, oil-based ink, and heat-discoloring ink can be prepared according to the use of the writing instrument. Fluorophores such as Basic Violet 11, Basic Yellow 40, and thermochromic microcapsule pigments can be contained.

As shown in FIGS. 3 and 4A, the writing core 30 has a U-shaped shape as a whole, and the ink guiding portions 31 and 31 and the ink derived from the ink guiding portions 31 and 31 are derived. It is provided with a writing unit 32. Reference numeral 33 is an inclined portion having an inclined outer shape on one side.
The writing core 30 is made of a porous member, and is, for example, a natural fiber, an animal hair fiber, a polyacetal resin, a polyethylene resin, an acrylic resin, a polyester resin, a polyamide resin, or a polyurethane resin. Parallel fiber bundles consisting of one or more combinations of polyolefin resin, polyvinyl resin, polycarbonate resin, polyether resin, polyphenylene resin, etc., fiber bundles such as felt, etc. are processed or these fiber bundles are resinified. Select from processed fiber cores, polyethylene, polymethylmethacrylate, polypropylene, ethylene-vinyl acetate copolymer, polystyrene, styrene-acrylonitrile copolymer, styrene-butadiene-acrylonitrile copolymer, polyamide, polycarbonate, polytetrafluoroethylene. It is made of a porous body (sintered core) obtained by sintering a granular thermoplastic resin such as a thermoplastic resin.
The writing core 30 is preferably a fiber bundle core, a fiber core, or a sintered core, and particularly preferably, at least the above-mentioned granular thermoplasticity from the viewpoint of highly compatible with manufacturability, ease of forming porosity, strength, and the like. A sintered core obtained by sintering a resin is desirable.

The writing core 30 is set so that the shear strength is 5N or more, and the shear strength of the writing core 30 is preferably within 0.6 mm in length t from the end surface on the tip side of the writing core 32 to the inner side. It is desirable that the shear strength is.
By setting the shear strength of the writing core 30 to 5N or more, it is possible to prevent damage to the writing core without impairing the writing performance even when writing with a strong writing load, and to make the writing core excellent in durability. It is more preferably 8N or more, and particularly preferably 10N or more and 30N or less.

In the present invention, the shear strength can be measured by using, for example, the shear strength measuring apparatus shown in FIGS. 4 (b) to 4 (d).
The shear strength measuring device 60 has a measuring jig insertion hole 62 for inserting the shear strength measuring jig 65 in the center of the device main body 61, and a writing core 30 for inserting the writing core 30 to be measured in the upper part of the side surface of the device main body 61. It has a core insertion hole 63, and the shear strength measuring jig 65 is connected to a load applying machine 66 that applies a load, and the load applying machine 66 is connected to a drive measuring machine such as a motor (not shown).
The shear strength of the writing core 30 is measured by using this measuring device 60 by inserting it into the writing core insertion hole 63 from the writing portion 32 side of the writing core 30 shown in FIG. 4A, specifically, the tip of the writing core 32. After inserting so as to be within the length t (0.6 mm) on the inner side from the end face on the side, insert the shear strength measuring jig 65 into the measuring jig insertion hole 62 from the vertical direction (directly above), and insert the writing core. By applying a load to the writing portion 32, which is the measurement site of 30, the target shear strength (withstand load: load at the time of breaking) is measured.

In the present invention, the shear strength of the writing core is 5 N or more, preferably the shear strength of the writing core 30 is within 0.6 mm in length t from the end surface of the writing core 32 tip side (writing portion 32) to the inner side. As long as the strength is 5 N or more, the material, pore ratio, shape, size, etc. of the writing core 30 are not limited, but as shown in FIGS. 3 and 4 (a), the entire writing core has a U-shaped shape. Therefore, a writing unit 30 including an ink guiding unit 31, 31 and a writing unit 32 for deriving ink from the ink guiding units 31, 31 and an L-shaped or T-shaped ink guiding unit 31. Is preferable.
The writing unit 32 is preferably a writing unit having a drawing line width of 1 mm or more, and more preferably a drawing line width of 2 mm or more.
The writing core 30 of the present embodiment is composed of a sintered core (sintered body) having a pore ratio of 60% obtained by sintering polyethylene powder having an average particle diameter of 5 μm, and the writing portion 32 has an upper side length of 4 mm and a lower side length. The ink guiding portion 31 having a size of 5 mm, a height of 2 mm, and an ink guiding portion 31 having a diameter of 2 mm and a length of 16 mm was used.

As shown in FIGS. 2 (a) and 3 (a) to 3 (f), the holding body 40 has a bulging main body portion 41, a flange portion 42 on the front side of the main body portion 41, and a writing direction. In addition to having a visible portion 43 capable of visually recognizing the above, a rear holding portion 45 having a holding piece 44 connected to the main body portion 41 is provided on the rear side of the main body portion 41. Further, a holding groove 46 for fitting and holding the U-shaped writing core 30 is formed on the entire longitudinal outer peripheral surface of the holding body 40 composed of these members.
Further, a concave fitting portion 41a is formed on the outer peripheral surface in the width direction of the main body 41, and air flow grooves 41b and 41b are formed on the outer peripheral surface in the longitudinal direction.
In this embodiment, the front surface portion 47 of the holding groove 46, which is a portion of the writing core 30 that comes into contact with the writing portion 32, is for preventing the writing portion 32 from being displaced during writing or the like to ensure holding. A non-smooth surface portion 48 having a concavo-convex shape with minute concavo-convex steps is formed.

The entire holder 40 configured in this way is amorphous in addition to general nylon such as PP, PE, PET, PEN, and nylon (6 nylon, 12 nylon, etc.) having visibility and flexibility. By molding from materials such as nylon), acrylic, polymethylpentene, polystyrene, ABS, etc., the characters written in the writing direction can be effectively visually recognized by the visible portion 43. It should be noted that only the visible portion 43 may be made of a material having visibility.
Further, the holding body 40 may be configured by using one kind of each of the above materials, or two or more kinds of materials from the viewpoint of further improvement of durability and visibility, injection molding, blow molding and the like. It can be molded by various molding methods.

In the writing instrument A of the present embodiment, one of the writing portions 32 of the writing core 30 is an inclined portion 32, and the writing core 30 has a structure that is securely fixed by being fitted into the holding groove 46 of the holding body 40. It has become. Further, when the pressure in the shaft body 10 increases, ink dripping or the like may occur from the pen core. In this form, the inside of the shaft body 10 and the outside air are connected to each other through the air flow grooves 41b and 41b. I'm adjusting. The cap 50 is detachably attached to the outer peripheral surface on the tip end side of the toe shaft 15 by fitting or the like. When the ink for writing tools is a heat-discolorable ink, it is preferable to form a thermoplastic elastomer on the outer surface of the cap 50 or the top of the cap 50 to make the cap easily generate frictional heat by the scraping operation.

In this writing instrument A, an ink storage body 20 that stores ink for writing instruments is inserted and held in a rear shaft 11 constituting the shaft body 10 of the writing instrument, and a toe shaft 15 and a sintered body having the above-mentioned specific shear strength are held. By attaching the writing core 30 composed of the above to the holding body 40 having the above configuration, the writing instrument A can be easily manufactured, and the ink stored in the ink storage body 20 is the writing portion 32 of the writing core 30 due to the capillary force. It will be efficiently supplied to and used for writing.

The writing tool A configured in this way is composed of at least a writing core 30 made of a porous body and a holding body 40 holding the writing core 30, and the shear strength of the writing core 30 is high. By setting it to 5N or more, preferably, the shear strength of the writing core 30 is strong by setting the shear strength within 0.6 mm in length t on the inner side from the end face on the tip side of the writing core 32 to 5N or more. It is possible to obtain a writing tool having excellent durability that can prevent damage to the writing core without impairing the writing performance even when writing with a writing load.
Further, as described above, in this writing instrument A, the holding body 40 that holds the writing core 30 is made of a material having visibility, so that the visible portion 43 of the holding body 40 determines the coating direction and the writing direction. A coating tool that can be used until the end of coating is provided, which is a visible portion that can be visually recognized, and can be provided with sufficient visibility to reliably visually recognize the characters and the coating portion written in that direction. Will be done.

ｘ＝５（Ｎ）、μ：平均値、σ：標準偏差
上記生産ロットごとのせん断強度測定・検査を継続することで、生産ラインにおける筆記芯３０の強度の変化が把握でき、せん断強度の低下等の生産トラブルも容易に回避することができるものとなる。なお、５Ｎ以下の累積確率（混入確率）が１００ｐｐｍ超過であると、歩留まりが悪くなる傾向となり、効率的な生産を発揮できないことが生じることとなる。 Further, in the writing tool of the present invention, by setting the shear strength of the writing core to 5N or more as described above, it is possible to prevent the writing core from being damaged even when writing with a strong writing load without impairing the writing performance. Since a writing tool having excellent durability can be obtained, for example, when the writing core 30 used in the above embodiments [FIGS. 1 and 4 (a)] is mass-produced on a production line, the above shear strength inspection is performed. In doing so, it is possible to make a pass / fail judgment for each production lot by performing a shear strength inspection for each production lot by the following statistical method.
From a certain production lot (100,000 pieces), 100 pieces (pieces) for measuring shear strength are arbitrarily extracted, shear strength is measured by the method detailed in FIG. 4, and the average value (μ) is obtained from the inspection data (normal distribution). ), The standard deviation (σ) is obtained, and in the probability density function f (x) of the standard normal distribution expressed by the following equation, the cumulative probability φ (z) and the probability variables 0 to 5 make the cumulative probability 5N or less (mixed). By setting the probability) to 100 ppm or less, the production lot can be made into a product as a pass lot.

x = 5 (N), μ: Mean, σ: Standard deviation By continuing the shear strength measurement and inspection for each production lot, changes in the strength of the writing core 30 in the production line can be grasped, and the shear strength decreases. Production troubles such as these can be easily avoided. If the cumulative probability (mixing probability) of 5N or less exceeds 100 ppm, the yield tends to be poor, and efficient production may not be exhibited.

The writing instrument of the present invention is a writing instrument in which a writing portion is composed of at least a writing core made of a porous body and a holding body that holds the writing core, and is characterized in that the shear strength of the writing core is 5N or more. Therefore, the present invention is not limited to the above embodiment, and various changes can be made without changing the technical idea of the present invention.
For example, in the above embodiment, the writing core 30 is described in detail about the sintered core type writing core. If the above shear strength is satisfied, the writing core 30 can be a fiber bundle or foam as described above, in addition to the sintered body. It may be a body, a spongy body, a felt body, or the like, and when the writing core 30 is a writing core made of a fiber bundle, a foam, or the like, for example, a writing core having a low pore ratio and a low foaming ratio (high density) is written. A writing core (fiber bundle core) 30 may be formed as a writing core (fiber bundle core) 30 by using a portion 32 having a high pore ratio and a high foaming ratio (low density) for the ink guiding portions 31 and 31, and an average particle size distribution. The writing core may be a combination of different thermoplastic materials (same material, different materials), and the shear strength of the writing portion 32 of the writing core 30 can be further improved. Even if the writing core 30 is changed to each of the above modes (strength of fiber bundle, foam, corpus cavernosum, felt body, etc., pore ratio, foaming ratio, etc.), the writing portion 32 from the ink storage body 12 can be reached. The ink supply mechanism is set so as to supply an appropriate amount of ink without damaging the ink supply mechanism and without causing the ink to run out.
Further, in each of the above embodiments, a writing tool of a method (filling type) in which the ink stored in the ink storage body 20 is efficiently supplied to the writing portion 32 of the writing core 30 by the capillary force is provided, but the writing tool is provided with a valve mechanism. A writing tool, for example, an ink chamber in which ink is directly stored in the shaft body of the writing tool is provided, a valve mechanism is provided between the ink chamber and the writing core, and the spring of the valve mechanism is moved by pressing in the direction of the pen tip. It may be a writing tool having a structure in which the valve rod is retracted against the urging force to release the valve portion to derive the ink and supply the ink to the writing core.

Furthermore, in the above embodiment, a single type writing instrument having one writing core 30 as a pen tip is mentioned, but a twin type writing instrument and a pen body composed of a fine writing type writing core are provided at the tip of the rear shaft to make ink. The ink of the storage body 20 may be supplied to the pen body.
Furthermore, in the above embodiment, although described with ink for writing tools, liquids such as liquid cosmetics, liquid chemicals, coating liquids, and correction fluids are used, and the writing core is combined with the liquids, for example, the desired shear strength. A suitable coating member provided with the above may be used.

Next, the present invention will be described in more detail by way of examples, but the present invention is not limited to the following examples.

[Example 1]
Writing tools and inks conforming to the following configurations and FIGS. 1 to 4 were used. The dimensions of the writing core, holder, etc. used were those shown below.

(Structure of writing core 30)
PE sintered core using polyethylene (PE) powder (melting point 130 ° C.) with an average particle diameter of 5 μm, pore ratio 60%, writing part: upper side length 4 mm, lower side length 5 mm, height 2 mm, ink guide part : Φ (t) 2 mm, length 16 mm, upper side length 4 mm, lower side length 5 mm, height 2 mm
Shear strength: The probability density function f (x) for failure at a shear strength of less than 5N (measured by the measuring device according to FIG. 4) at t = 0.5 mm was 47 ppm.
The average particle diameter indicates the average value of the diameters of the particles measured with an electron microscope, and is the average value of the particle diameters measured for 20 particles in the image projected on the electron microscope. If the particle is not circular, the particle is the value obtained by adding the length of the longest line segment and the length of the shortest line segment and dividing by 2 among the line segments connecting any two points of the contour forming the pores. The particle size of. The porosity is measured by immersing a writing core having a known mass and apparent volume in water, sufficiently immersing the writing core in water, and then taking it out of the water. From the measured mass, the volume of water soaked in the writing core is calculated. It is calculated from the following formula (A), assuming that the volume of this water is the same as the volume of the pores of the writing core.
Porosity (unit:%) = (volume of water) / (apparent volume of writing core) x 100 …… (A)
(Structure of holder 40)
Made of acrylic resin (melting point 160 ° C.), visible light transmittance 85% [Reflectance was measured with a multi-light source spectrophotometer (MSC-5N) manufactured by Suga Test Instruments Co., Ltd. and used as the visible light transmittance. ]
Size of visible part 43 (square) after attaching the writing core: 5 mm x 6 mm x 3 mm x 4 mm
Non-smooth surface portion 48: Concavo-convex shape: Length 2.0 mm, Concavo-convex step: 0.1 mm, Occupancy ratio: Overall surface portion 47

(Structure of writing tool members other than writing core 30 and holding body 40)
Ink occlusion body: PET fiber bundle, porosity 85%, φ6 x 77 mm
Writing tool body, cap: Made of polypropylene (PP)

(Ink composition)
As the ink, ink having the following composition (total 100% by mass) was used.
Moisturizer: Trimethylglycine (glycine betaine) 7.5% by mass
Pentaerythritol 4.5% by mass
Colorant: NKW-4805 Yellow (manufactured by Nippon Fluorescent Co., Ltd.) 40.0% by mass
Preservative: Bio Ace (manufactured by Keiai Kasei Co., Ltd.) 0.3% by mass
pH regulator: triethanolamine 1.0% by mass
Fluorosurfactant: Surflon 8111N (manufactured by AGC Seimi Chemical Co., Ltd.) 0.2% by mass
Water-soluble organic solvent: Ethylene glycol 3.0% by mass
Water (solvent): Ion-exchanged water 43.5% by mass

In the writing tool of the first embodiment, the writing core 30 having the above characteristics was attached to the holding body 40 shown in FIG. 2 (FIG. 3). After the writing core 30 was fixed to the holding body 40, the writing core 30 was attached to the writing tool shaft body 10 via the toe shaft 15 to manufacture the writing tool shown in FIG.
According to the writing instrument of the first embodiment, since the shear strength of the writing core 30 is set to 10N (5N or more), even if writing with a strong writing load, the writing performance is not impaired and the writing core is prevented from being damaged. It was confirmed that a writing instrument with excellent durability that can be obtained can be obtained.
Further, since at least a part of the surface portion 47 of the holding body 40 in contact with the writing core 30 has a non-smooth surface shape 48, the writing core can be reliably attached to the holding body with a simple structure without using an adhesive or the like. It was able to be fixed, stabilized in the assembly process, and manufactured at low cost.
In addition, when writing on the characters using the obtained writing instrument, when the appearance on the other side was visually confirmed through the visible part at the time of writing, the visibility was sufficient, it was easy to see, and it was in the writing direction. I was able to write while reading the written characters.

Furthermore, this writing instrument is set in the automatic writing device, and according to JIS S6037, the writing angle is 65 °, the writing load is 10 N, the speed is 7 cm / s, and the distance is 100 m. As a result, it was found that the writing core was not broken or damaged, the writing performance was good, there was no blurring of drawn lines, and the ink flow rate was also good.

[Example 2]
In Example 1 above, the composition of the writing core 30 is changed from the PE sintered core to the PP ink core (pore ratio 60%) using polypropylene resin powder (melting point 160 ° C.) having an average particle diameter of 5 μm. Manufactured a writing tool without changing the shape, size, etc. of the writing portion, and further, without changing the configuration of the holding body 40, the ink occlusion body, the writing tool main body, the cap, and the ink composition. Shear strength at that time: The probability density function f (x) for breakage was 64 ppm when the shear strength was less than 5N (measured by the measuring device according to FIG. 4) at t = 0.5 mm.
Even in the writing tool of Example 2, even if the material of the writing core is changed, the same action and effect as in Example 1, that is, even if writing with a strong writing load, the writing performance is not impaired and the writing core is damaged. A writing tool with excellent durability that can prevent the problem from occurring is obtained, and the writing core is firmly fixed to the holder with a simple structure without using adhesives, etc., and the assembly process is stabilized and the cost is low. Furthermore, when writing on the letters using the obtained writing tool, the visibility on the other side was visually confirmed through the visible part at the time of writing, and the visibility was sufficient. Yes, it was easy to see, and I was able to write while reading the characters written in the writing direction.
In addition, this writing instrument is set in the automatic writing device, and according to JIS S6037, the writing angle is 65 °, the writing load is 10N, the speed is 7cm / s, and the distance is 100m. As a result, it was confirmed that the writing core was not broken or damaged, the writing performance was good, there was no blurring of drawn lines, and the ink flow rate was also good.

The writing instrument of the present invention can be suitably used for a type of writing instrument called an underline pen, a paint marker, an oil-based marker, and a water-based marker.

A Writing tool 10 Axis body 11 Rear axis 15 Front axis 20 Ink occlusion body 30 Writing core 40 Holding body 50 Cap

Claims (1)

At least, a writing instrument in which a writing instrument is composed of a writing core having a U-shaped shape, an L-shaped shape, and a T-shaped body as a whole, and a holding body holding the writing core. Therefore, the shear strength of the writing core from the end surface on the tip side of the writing core is 5 N or more, and the front surface portion of the holding groove of the holding body, which is the part that comes into contact with the writing portion of the writing core, is non-smooth due to the uneven shape. A writing instrument characterized in that a face portion is formed .

Images