JP7743438B2 - writing implements - Google Patents

Description

The present invention relates to a writing instrument. In particular, it relates to a writing instrument (such as a marking pen) that includes a pen tip and a holding member that holds the pen tip.

For example, Patent Document 1 discloses a writing implement that is supported so that it can tilt freely, with the force applied to the barrel as writing occurs, bringing the entire writing head into contact with the writing surface. Because the pen body tilts so that the entire writing head contacts the writing surface, it is easy to draw lines of a consistent width.

In Patent Document 2, the applicant discloses a writing instrument that ensures that the entire writing part comes into contact with the paper surface, thereby ensuring that a consistent line width is obtained.

Figure 11 is a side view of the writing instrument 101 according to Patent Document 2, Figure 12 is an enlarged view of the main parts of Figure 11, Figure 13 is an enlarged oblique view of the main parts of Figure 12, and Figure 14 is a vertical cross-sectional view of Figure 12.

As shown in Figures 11 to 14, the writing implement 101 of Patent Document 2 includes a pen tip 102 and a holding member 103 that holds the pen tip 102.
The front portion 123 of the pen tip 102 extends in the axial direction,
The cross section of the front part 123 of the pen tip 102 in the extension direction has a substantially rectangular shape,
The tip of the holding member 103 has a holding portion 131 that surrounds the front portion 123 of the pen tip 102,
The holding portion 131 has notched openings 133 on both long sides of the substantially rectangular cross section of the front portion 123 of the pen tip 102,
The top 122 of the pen tip 102 is formed in a substantially linear shape in a side view and forms an acute angle with respect to the extending direction of the front part 123 of the pen tip 102.
The rear edge 134 of the opening 133 is formed in a substantially straight line in a side view and is parallel to the top 122 of the pen tip 102.
The holding portion 131 has a pair of extension pieces 135 extending in a direction approximately parallel to the extension direction of the front portion 123 of the pen tip 102 on both short sides of the approximately rectangular cross section of the front portion 123 of the pen tip 102.

The notched opening 133 allows the pen tip 102 to flex and deform along its long side when writing. This allows the entire writing part to contact the paper surface, ensuring a consistent line width. Furthermore, the contact of the pair of extension pieces 135 with the paper surface encourages writing with the designed writing pressure and prevents excessive flexing (and consequent damage) of the pen tip 102.

Japanese Patent Application Laid-Open No. 2005-297540 Japanese Patent Application Laid-Open No. 2019-155879

The writing instrument described in Patent Document 2 has the advantages described above, but the inventors have discovered the following improvements:

That is, as shown in Figure 15, when drawing a straight line using the ruler, the inner extension piece 135 contacts the ruler at an angle, making the pen tip 102 unstable. As a result, it may not be easy to draw a straight line as intended.

Alternatively, as shown in Figure 16, when drawing a straight line without using a ruler, the top 122 of the pen tip 102 forms an acute angle with the extension direction of the front part 123 of the pen tip 102 (and the pair of extension pieces 135), so direction A in which the pen tip 102 is bent (sunk into the paper surface) and direction B in which the pen tip 102 is moved form an acute angle (intersect in a plan view). This can make it difficult to draw a straight line as intended.

The present invention was made in light of the above findings. The object of the present invention is to provide a writing instrument that is supported so that it can tilt freely so that the entire pen tip is in contact with the paper surface, and that makes it relatively easy to draw straight lines as intended, both when using a ruler and when drawing straight lines without using a ruler.

The present invention provides
The pen tip and
a holding member for holding the pen tip;
A writing instrument comprising:
The front part of the pen tip extends in a linear direction inclined at an acute angle with respect to the axial direction in a side view,
A cross section of the front part of the pen tip relative to the extension direction has a substantially rectangular shape,
the holding member has a holding portion that surrounds at least a portion of the front portion of the pen tip,
The holding portion has openings on both long sides of the substantially rectangular cross section of the front portion of the pen tip,
The tip of the pen tip is formed in a substantially straight line in a side view and is substantially perpendicular to the extension direction of the front part of the pen tip,
a rear edge of the opening is formed in a substantially straight line in a side view and is substantially parallel to the top of the pen tip;
The holding portion is a writing instrument characterized in that it has an extension piece that extends in a direction approximately parallel to the extension direction of the front part of the pen tip on the short side of the approximately rectangular cross section of the front part of the pen tip, which is the inner short side when viewed from the side.

According to the present invention, the extension piece extends in a direction approximately parallel to the extension direction of the front part of the pen tip. Therefore, when drawing a straight line using a ruler, the extension piece can make line or surface contact with the ruler, ensuring stability of the pen tip (see Figure 7). This makes it easy to draw a straight line as intended. Furthermore, even when drawing a straight line without using a ruler, the direction in which the pen tip is bent (sunk into the paper) and the direction in which the pen tip is moved are the same in a planar view (see Figure 8). This makes it easy to draw a straight line as intended.

Preferably, the holding portion has a pair of extension pieces extending in a direction approximately parallel to the extension direction of the front portion of the pen tip on both short sides of the approximately rectangular cross section of the front portion of the pen tip.

In this case, contact of the pair of extension pieces with the paper surface more effectively encourages writing with the designed writing pressure, and more effectively prevents excessive bending (and therefore damage) of the pen tip.

Also, preferably, the rear connection portion of the front portion of the pen tip that is continuous with the front portion extends generally in the axial direction.

This makes it possible to change the design of only the front part of the pen tip and the holding part of the holding member surrounding it from conventional writing instruments.

In this case, it is even more preferable that the connection portion of the pen tip has a narrowed portion whose cross-section changes relative to the axial direction.

This makes it easier to insert the pen tip into the holding member (see Figure 5).

Also, preferably, the width of the opening is greater than the width of the long side of the approximately rectangular cross section of the front part of the pen tip.

This means that the front part of the pen tip is not pressed against the inner surface of the extension piece when writing, allowing it to bend and deform more reliably toward the long side. Regardless of the angle of the pen tip relative to the paper surface, the entire pen tip comes into contact with the paper surface, ensuring a consistent line width.

Preferably, the pen further comprises a barrel connected to the holding member, the rear portion of the holding member being attached to the front portion of the barrel, a first abutment wall portion being formed on the inner surface of the holding member, and a second abutment wall portion being formed on the inner surface of the barrel, and the outer surface of the nib being clamped in the front-to-back direction by the first abutment wall portion and the second abutment wall portion.

This effectively prevents the pen tip from falling out of the holding member or from becoming embedded in the holding member, and also allows the amount of protrusion of the pen tip from the holding member to be accurately maintained.

Preferably, the nib is either a fiber nib, a felt nib, a nib made of a porous material with open cells, or a plastic nib with an axial capillary passage.

This allows the pen tip to have the desired flexibility, which allows it to bend and deform more reliably along the long side, ensuring that the entire pen tip comes into contact with the paper surface regardless of the angle of the pen tip relative to the paper surface, and ensuring a consistent line width.
Preferably, the tip of the front part of the pen tip is provided with a chamfered portion on the side that is inclined at an acute angle in a side view.
This effectively prevents breakage and peeling at the tip on the acutely inclined side (inner side) of the front part of the nib. In particular, when the nib is a fiber nib, the fibers are arranged in the axial direction during the manufacturing process, and if the tip on the inner side of the front part of the nib is at a right angle, that part becomes a collection of short fibers and is very fragile. By providing a chamfered portion in that part, the fibers constituting that part become longer, significantly reducing brittleness and effectively preventing breakage and peeling. Even in cases where the nib is made of a porous material with open cells, if the tip on the inner side of the front part of the nib is at a right angle, that part will be very fragile. Even in this case, by providing a chamfered portion in that part, the fragility of that part will be significantly reduced and breakage and peeling will be effectively prevented.

According to the present invention, the extension piece extends in a direction approximately parallel to the extension direction of the front part of the pen tip. Therefore, when drawing a straight line using a ruler, the extension piece can make line or surface contact with the ruler, ensuring stability of the pen tip (see Figure 7). This makes it easy to draw a straight line as intended. Furthermore, even when drawing a straight line without using a ruler, the direction in which the pen tip is bent (sunk into the paper) and the direction in which the pen tip is moved are the same in a planar view (see Figure 8). This makes it easy to draw a straight line as intended.

1 is a vertical cross-sectional view showing a writing implement according to an embodiment of the present invention. FIG. 2 is an enlarged view of a main part of FIG. 1 . 3(a) is a side view of the pen tip of FIG. 1, and FIG. 3(b) is a perspective view. 4(a) is a side view of the holding member of FIG. 1, and FIG. 4(b) is a perspective view. 5 is a schematic side view of the pen tip of FIG. 3 being inserted into the holding member of FIG. 4. [0023]FIG. 6(a) is a side view of the pen tip of FIG. 3 inserted into the holding member of FIG. 4, and FIG. 6(b) is a perspective view. 7A, 7B, and 7C are explanatory diagrams illustrating a case where a straight line is drawn using a ruler with the writing implement according to the present embodiment, where FIG. 7A is a schematic perspective view, FIG. 7B is a schematic front view, and FIG. 7C is a schematic plan view. 8A and 8B are explanatory diagrams illustrating a case where a straight line is drawn using the writing implement according to the present embodiment without using a ruler, with FIG. 8A being a schematic perspective view and FIG. 8B being a schematic plan view. FIG. 9(a) is a side view of a modified pen tip, and FIG. 9(b) is a perspective view. FIG. 10 is a side view of a modified example of the holding member. FIG. 1 is a side view of a writing implement according to Patent Document 2. FIG. 12 is an enlarged view of a main part of FIG. 11 . FIG. 13 is an enlarged perspective view of a main part of FIG. 12 . FIG. 13 is a longitudinal cross-sectional view of FIG. 12. 15A, 15B, and 15C are explanatory diagrams of drawing a straight line using a ruler with a writing implement according to Patent Document 2, in which FIG. 15A is a schematic perspective view, FIG. 15B is a schematic front view, and FIG. 15C is a schematic plan view. 16A and 16B are explanatory diagrams of drawing a straight line using a writing implement according to Patent Document 2 without using a ruler, in which FIG. 16A is a schematic perspective view and FIG. 16B is a schematic plan view. FIG. 17(a) is a side view of the pen tip of the writing implement according to the second embodiment of the present invention, and FIG. 17(b) is a perspective view. FIG. 18(a) is a side view of a holding member of a writing implement according to a third embodiment of the present invention, and FIG. 18(b) is a perspective view. 19A and 19B are explanatory views of a case where a straight line is drawn using a ruler with a writing implement according to a third embodiment of the present invention, where FIG. 19A is a schematic perspective view and FIG. 19B is a schematic front view. FIG. 20(a) is a side view of a holding member of a writing implement according to a fourth embodiment of the present invention, and FIG. 20(b) is a perspective view. 21A and 21B are explanatory views of a case where a straight line is drawn using a ruler with a writing implement according to a fourth embodiment of the present invention, with FIG. 21A being a schematic perspective view and FIG. 21B being a schematic front view. FIG. 22(a) is a side view of the pen tip of a writing implement according to a fifth embodiment of the present invention, and FIG. 22(b) is a perspective view.

The following describes an embodiment of the present invention with reference to the drawings.

Figure 1 is a longitudinal cross-sectional view showing a writing instrument 1 according to this embodiment, Figure 2 is an enlarged view of a main portion of Figure 1, Figure 3(a) is a side view of the pen tip 2 of Figure 1, Figure 3(b) is a perspective view of the pen tip 2 of Figure 1, Figure 4(a) is a side view of the holding member 3 of Figure 1, and Figure 4(b) is a perspective view of the holding member of Figure 1. Figure 5 is a schematic side view of the pen tip 2 of Figure 3 in the middle of being inserted into the holding member 3 of Figure 4, Figure 6(a) is a side view of the pen tip 2 of Figure 3 inserted into the holding member 3 of Figure 4, and Figure 6(b) is a perspective view thereof.

(Overall structure)
1 to 6, the writing instrument 1 according to this embodiment includes a pen tip 2 and a holding member 3 that holds the pen tip 2. The writing instrument 1 according to this embodiment also includes an ink reservoir 6, and a front barrel 4 and a rear barrel 5 that house the ink reservoir 6 therein. The holding member 3 is press-fitted into the front barrel 4.

(Pen tip 2)
The nib 2 is made of a fiber nib (a resin-processed fiber bundle). However, the nib 2 may be any flexible material that allows ink to flow through it, and specific examples include a porous synthetic resin material with open cells, a felt nib, a brush nib, and a plastic nib with an axial capillary passage.

The front portion 23 of the pen tip 2 extends in a linear direction inclined at an acute angle (30° in this embodiment) relative to the axial direction in a side view. The cross section of the front portion 23 of the pen tip 2 in the extension direction is approximately rectangular (long side 4.5 mm, short side 1 to 3 mm). The extension length (the length that maintains the approximately rectangular cross section) is 2.6 mm in this embodiment.

The front portion 23 of the pen tip 2 is sandwiched (partially surrounded) by a pair of extension pieces 35 of the holding member 3, which will be described later, and the top portion 22 of the pen tip 2 protrudes slightly forward (diagonally forward) from the tip of the holding member 3. The top portion 22 of the pen tip 2 is formed in a substantially straight line in side view and is perpendicular to the extension direction of the front portion 23 of the pen tip 2.

Here, it is preferable that the tip 22 of the nib 2 has a convex curved R-shape. In the writing instrument 1 of this embodiment, the nib 2 flexes, so that the entire nib 2 comes into contact with the paper surface regardless of the angle of the nib 2 relative to the paper surface, ensuring a consistent line width. Therefore, it is preferable that the tip 22 has an R-shape so that the tip 22 can reliably come into contact with the paper surface.

In addition, a notch 23d is provided in at least one of the front portion 23 of the nib 2 or the connecting portion 23b on the side where the front portion 23 of the nib 2 is inclined at an acute angle relative to the axial direction in side view. This makes it easy to form a nib shape by grinding, punching, or the like, in which the front portion 23 of the nib 2 extends in a linear direction inclined at an acute angle relative to the axial direction in side view.

On the other hand, the connecting portion 23b on the rear side of the front portion 23 of the nib 2, which is continuous with the front portion 23, extends generally in the axial direction. However, the connecting portion 23b is provided with a tapered portion 23c whose cross section changes in the axial direction. The front end side of the tapered portion 23c is continuous with the front portion 23 of the nib 2 (its cross section in the extension direction of the front portion 23 of the nib 2 is generally rectangular), and the rear end side of the tapered portion 23c is generally square prism-shaped (its cross section in the axial direction is generally rectangular). In other words, the connecting portion 23b on the rear side of the front portion 23 has a generally rectangular cross section. Furthermore, the tapered portion 23c is at least a part of the notch 23d, and the tapered portion 23c can also be easily processed by grinding, punching, or the like.

In addition, on the rear side of the connection portion 23b of the pen tip 2, there is a cylindrical (large diameter) central portion 24 whose outer surface is clamped in the front-to-rear direction by the holding member 3 and the front shaft 4, and a cylindrical (small diameter) rear end portion 25 which is connected in a piercing manner to the front end portion of the ink absorbing body 6.

(Holding member 3)
The holding member 3 is a cylindrical body made of synthetic resin by injection molding, with both ends open. As shown in Figures 3 to 6, the pen tip 2 is fitted into the holding member 3 from the rear side (locked in the axial direction to prevent it from coming off).

Multiple (here, four) axially extending inner ribs are formed at equal intervals on the inner surface of the circular cross section at the rear end of the retaining member 3, into which the central portion 24 of the nib 2 is press-fit. Meanwhile, multiple (here, six) axially extending outer ribs are formed at equal intervals on the outer surface of the circular cross section at the rear end of the retaining member 3, into which the front barrel 4 is press-fit. Because the rear end of the retaining member 3 has a circular cross section, when the retaining member 3 and front barrel 4 are mated, the outer surface of the retaining member mating portion of the front barrel 4 also has a circular cross section, ensuring a secure, airtight fit between the inner surface of the cap and the outer surface of the front barrel 4. The communication holes formed by the outer ribs and the front barrel 4 function as air vents, allowing for smooth ink ejection from the nib 2.

As shown in Figures 1 to 6, the holding member 3 has a holding portion 31 with a substantially rectangular cross section that generally surrounds the front portion 23 and connection portion 23b of the nib 2. Because the connection portion 23b of the nib 2 has a substantially rectangular cross section, and the holding portion 31 of the holding member 3 also has a substantially rectangular cross section, they serve as guides that allow for alignment in the rotational direction (circumferential direction) when inserting the nib 2 into the holding member 3 for assembly. This makes it easy to align the rotational orientation of the nib 2 and the holding member 3. Furthermore, notched openings 33 are provided on both long sides of the substantially rectangular cross section of the front portion 23 of the nib 2.

The width of the opening 33 is greater than the width of the long side of the approximately rectangular cross section of the front portion 23 of the pen tip 2.

When not writing, the pen tip 2 is positioned on the axis of the writing instrument 1. On the other hand, when writing, the pen tip 2 flexes and deforms toward the opening 33 (longer side), allowing it to move away from the axis of the writing instrument 1. This allows the entire tip 22 of the pen tip 2 to come into contact with the paper surface, regardless of the angle between the axis of the writing instrument 1 and the paper surface, ensuring that a consistent line width is always obtained.

The top 22 of the nib 2 is formed in a generally straight line in side view, extending in a direction perpendicular to the extension direction of the front part 23 of the nib 2, and the rear edge 34 of the opening 33 is also formed in a generally straight line in side view, extending in a direction parallel to the top 22 of the nib 2. This ensures that the load on the nib 2 caused by bending of the nib 2 is applied evenly to the front part 23 of the nib 2, avoiding localized stress concentration on the nib 2 and extending the life of the nib 2.

In addition, the shape of the pen tip 2 exposed from the holding member 3 in a side view is rectangular, so the orientation of the pen tip 2 can be determined from the orientation of the rear end edge 34. Therefore, once the pen tip 2 is exposed, it can be used for writing immediately.

Here, at least at the time of filing this application, an embodiment in which the opening 33 is provided in only one side wall of the holding portion 31 is also considered to be one aspect of the present invention. However, if the opening 33 is provided in both walls, the desired bending effect can always be achieved regardless of whether the user is right-handed or left-handed, which is more convenient.

In addition, the holding portion 31 of this embodiment has a pair of extension pieces 35 (an inner extension piece 35a and an outer extension piece 35b) that protrude forward (perpendicular to the rear edge 34) from the rear edge 34 of the opening 33 on both short sides of the approximately rectangular cross section of the front portion 23 of the pen tip 2. The pair of extension pieces 35 extend in a direction parallel to the extension direction of the front portion 23 of the pen tip 2, and are designed to come into contact with the paper surface when writing.

By having the pair of extension pieces 35 come into contact with the paper surface, the pen tip 2 is prevented from bending too much and becoming broken or damaged, and the entire pen tip 2 can be brought into contact with the paper surface.

It is preferable that each of the pair of extension pieces 35 tapers forward (perpendicular to the rear edge 34) and that a convex curved surface is formed at its front end.

In addition, because the pair of extension pieces 35 come into contact with the paper surface, when drawing a line on the paper using a ruler or the like, the inner extension piece 35 can make line or surface contact with the ruler or the like, stabilizing the pen tip 2 (see Figure 7). This makes it easy to draw the line as intended. Furthermore, because the pen tip 2 does not come into contact with the ruler or the like, it is possible to prevent the ruler or the like from being soiled by ink, and conversely, it is also possible to prevent dirt on the ruler or the like from transferring to the pen tip 2 and smudging the handwriting when writing.

In addition, even when drawing a line without using a ruler or the like, the direction A in which the pen tip 2 is bent (sunk into the paper) and the direction B in which the pen tip 2 is moved are the same in a plan view (see Figure 8). This makes it easy to draw a line as intended.

Furthermore, by providing the holding member 3 with a pair of extension pieces 35, it is possible to prevent ink from adhering to the inner surface of the cap when the nib 2 comes into contact with the inner surface of the cap when inserting the nib 2 into the cap of the writing instrument 1. If ink adheres to the inner surface of the cap, the ink adhering to the inner surface of the cap may be transferred to the outer surface of the front barrel 4 when the cap is fitted onto the writing instrument 1. This may result in the user's hands becoming soiled with ink when removing the cap again and gripping the front barrel 4 of the writing instrument 1.

Furthermore, because the retaining member 3 has an inward extending piece 35a, the inward extending piece 35a and the step formed by the front portion 23 of the nib and the notch 23d (narrowed portion 23c) lock the retaining member 3 in the axial direction. This allows for a more stable fit between the nib 2 and retaining member 3.

The tip 22 of the pen tip 2 protrudes in the extension direction from the tip of the pair of extension pieces 35, and it is effective for the amount of protrusion to be greater than 0.2 mm and less than 5.0 mm, and preferably greater than 0.5 mm and less than 2.0 mm. The smaller the protrusion amount within this preferred range, the more rigid and firm the writing feel will be, and the greater the protrusion amount within this preferred range, the softer the writing feel will be.

It is also preferable that the rear end edge 34 be chamfered or rounded. In particular, it is preferable that the edge on the side of the pen tip 2 that is likely to come into contact with the pen tip 2 be chamfered or rounded. This minimizes the load on the front portion 23 of the pen tip 2, even if the pen tip 2 bends excessively and comes into contact with the rear end edge 34, and more effectively prevents the pen tip 2 from breaking or being damaged.

In addition, at least at the time of filing this application, an embodiment in which the extension piece 35 is provided only on the inner short side when viewed from the side (i.e., an embodiment in which only the inner extension piece 35a is provided) is also one embodiment of the present invention.

It is also preferable that the color of the holding member 3 is different from the color of the nib 2 (i.e., the ink color). This makes the orientation of the rear end edge 34 more prominent, making it easier to confirm the orientation of the nib 2. In particular, if the nib 2 itself is colored a dark color such as black and the holding member 3 is colored a lighter color different from the nib 2, the orientation of the rear end edge 34 will be even more prominent, making it easier to confirm the shape of the nib 2.

Furthermore, the holding member 3 may be made entirely of a transparent or translucent material. In this case, the color of the ink is easier to see. It also provides a form that is excellent in terms of design (aesthetics).

Alternatively, only the area near the front end of the holding member 3 may be colored, with the remainder being made of a transparent or translucent material. This configuration has the effect of making it easier to grasp the relative positions of the writing instrument and the writing object when the color of the writing object (e.g., paper) and the color of the ink are similar.

(Front axis 4)
The front body 4 is a cylindrical body made of synthetic resin by injection molding or extrusion molding, with both ends open. As shown in Figures 1 and 2, the outer surface of the rear end of the retaining member 3 (external ribs) is press-fitted onto the inner surface of the front end of the front body 4.

Furthermore, multiple (eight in this example) vertical ribs 43 extending in the axial direction are integrally formed at equal intervals on the rear inner peripheral surface of the front barrel 4. The central portion 24 of the nib 2 is clamped in the front-to-rear direction between the first abutment wall portion 36 of the retaining member 3 and the second abutment wall portion 41 at the front end of the vertical ribs 43.

This prevents the nib 2 from falling out of the holding member 3 or becoming embedded in the holding member 3 (front barrel 4), and accurately regulates the amount of protrusion of the nib 2 from the holding member 3. Furthermore, the front end of the ink occlusion body 6 is clamped in the front-to-rear direction between the third abutment wall portion 42 at the rear end of the vertical rib 43 and the bottom wall of the barrel tube 5, which will be described later.

(rear shaft 5)
The rear axle 5, which is connected to the rear end of the front axle 4, is a cylindrical body with a bottom, an open front end, and a closed rear end, and is made by injection molding a synthetic resin (such as polypropylene). The front axle 4 is airtightly fitted into the rear axle 5 by screwing or press-fitting.

(Ink occlusion body 6)
The ink occlusion body 6 is made of a material having continuous pores that can be impregnated with ink. Examples include a heat-fused fiber bundle, a resin-processed fiber bundle, a resin-processed felt, a needle-punched felt, a porous body (for example, an open-cell synthetic resin body such as a sponge), etc. The ink occlusion body 6 may also have an outer skin made of a synthetic resin film or the like on its outer periphery.

(Action and effect)
The writing instrument 1 configured as described above can achieve the following effects. That is, according to the writing instrument 1 of this embodiment, the extension piece 35 extends in a direction substantially parallel to the extension direction of the front portion 23 of the pen tip 2. Therefore, when drawing a line using a ruler, the extension piece 35 can make line contact or surface contact with the ruler, and the pen tip 2 is stable (see FIG. 7 ). This makes it easy to draw a line as intended.

Furthermore, with the writing instrument 1 of this embodiment, even when drawing a line without using a ruler, the direction A in which the pen tip 2 is bent (sunk into the paper) and the direction B in which the pen tip 2 is moved are the same in a plan view (see Figure 8). This makes it easy to draw a line as intended.

Furthermore, the holding portion 31 of the writing instrument 1 of this embodiment has a pair of extension pieces 35 that extend in a direction approximately parallel to the extension direction of the front portion 23 of the pen tip 2 on both short sides of the approximately rectangular cross section of the front portion 23 of the pen tip 2. Therefore, contact of the pair of extension pieces 35 with the paper surface more effectively encourages writing with the designed writing pressure, and more effectively prevents excessive bending (and therefore damage) of the pen tip 2.

Furthermore, according to the writing instrument 1 of this embodiment, the connecting portion 23b on the rear side of the front portion 23 of the nib 2, which is continuous with the front portion 23, extends generally in the axial direction. As a result, it is sufficient to change the design of only the front portion 23 of the nib 2 and the holding portion 31 of the holding member 3 surrounding it from the conventional writing instrument 101.

Furthermore, according to the writing instrument 1 of this embodiment, the connection portion 23b of the nib 2 is provided with a narrowed portion 23c whose cross section changes relative to the axial direction. This makes it easier to insert the nib 2 into the holding member 3 (see Figure 5).

However, at least at the time of filing this application, an embodiment in which the narrowed portion 23c is not provided is also an embodiment of the present invention. That is, as shown in Figure 9(a), the pen tip 2' may have a constant cross section in the axial direction throughout the entire connecting portion 23b'. The corresponding holding member 3' has a configuration as shown in Figure 10. Furthermore, as shown in Figure 9(b), the top 22 of the pen tip 2' may have a rectangular writing surface. This makes it easier to process the shape of the top 22 of the pen tip 2'.

Furthermore, with the writing instrument 1 of this embodiment, the width of the opening 33 is greater than the width of the long side of the approximately rectangular cross section of the front portion 23 of the nib 2. This allows the nib 2 to more reliably flex and deform toward the long side when writing, ensuring that the entire nib 2 comes into contact with the paper surface regardless of the angle of the nib 2 relative to the paper surface, ensuring a consistent line width.

Furthermore, the writing instrument 1 of this embodiment further comprises a front shaft 4 connected to the retaining member 3, the rear portion of the retaining member 3 is attached to the front portion of the front shaft 4, a first abutment wall portion 36 is formed on the inner surface of the retaining member 3, a second abutment wall portion 51 is formed on the inner surface of the front shaft 4, and the outer surface of the nib 2 is clamped in the front-to-rear direction by the first abutment wall portion 36 and the second abutment wall portion 41. This effectively prevents the nib 2 from falling out of the retaining member 3 or from sinking into the retaining member 3, and furthermore, the amount of protrusion of the nib 2 from the retaining member 3 can be accurately maintained.

The nib 2 is either a fiber nib (a resin-processed fiber bundle), a felt nib, a nib made of a porous material with open cells, or a plastic nib with axial capillary passages. This allows the nib 2 to have the desired flexibility. This allows for more reliable bending and deformation along the long side, ensuring that the entire nib 2 comes into contact with the paper surface regardless of the angle of the nib 2 relative to the paper surface, ensuring a consistent line width.

Second Embodiment
Figure 17(a) is a side view of a nib 202 of a writing instrument according to a second embodiment of the present invention, and Figure 17(b) is a perspective view of the nib 202. As shown in Figures 17(a) and 17(b), the nib 202 of the second embodiment has a notch 223d, so that the front portion 223 has a plate-like, approximately rectangular parallelepiped shape. The top portion 222 has a flat surface, and is not provided with a convex, curved, R-shaped portion.

The front portion 223 of the pen tip 202 extends in a linear direction inclined at an acute angle (30° in this embodiment) to the axial direction in a side view, similar to the front portion 23 of the pen tip 2 in the previously described embodiment. The cross section of the front portion 223 of the pen tip 202 in the extension direction is approximately rectangular (long side 4.5 mm, short side (thickness) 1.5 mm). The extension length (the length maintaining the approximately rectangular cross section) is 2.5 mm in this embodiment.

The front portion 223 of the pen tip 202 is sandwiched (partially surrounded) by a pair of extending pieces of a corresponding holding member (not shown), and the top portion 222 of the pen tip 202 protrudes slightly forward (diagonally forward) from the tip of the holding member. The top portion 222 of the pen tip 202 is formed in a substantially straight line in side view and is perpendicular to the extending direction of the front portion 223 of the pen tip 202.

Here, the top 222 of the pen tip 202 does not have a convex curved R-shape but is a flat surface, so the top 222 has a smaller contact area with the paper surface during writing compared to the top 22 of the pen tip 2 in the previously described embodiment. This reduces the amount of "ink puddle" that can form on the paper surface when the pen tip 202 is removed from the paper surface after writing.

In addition, in this embodiment, a notch 223d is provided on the side of the front portion 223 of the pen tip 202 that is inclined at an acute angle relative to the axial direction in a side view, so that the front portion 223 of the pen tip 202 has an approximately rectangular parallelepiped shape. Here, in the embodiment shown in Figures 17(a) and 17(b), the front end of the notch 223d is located slightly rearward of the apex 222, so the front portion 223 of the pen tip 202 does not have a perfect rectangular parallelepiped shape; however, the position of the front end of the notch 223d may be aligned with the apex 222 to give the front portion 223 of the pen tip 202 a perfect rectangular parallelepiped shape.

On the other hand, the connecting portion 223b, which is continuous with the front portion 223 of the pen tip 202 and is located rearward of the front portion 223, extends generally in the axial direction. In this embodiment, the connecting portion 223b is plate-shaped and has the same thickness as the front portion 223, but includes a narrowed portion 223c whose cross-section changes relative to the axial direction; a transition portion 223e which extends rearward from the rear end of the narrowed portion 223c and gradually increases in thickness; and a rear portion 223f which extends rearward from the rear end of the transition portion 223e with a constant thickness. The boundary line between the narrowed portion 223c and the transition portion 223e, and the boundary line between the transition portion 223e and the rear portion 223f, are both parallel to the apex 222. The change in the cross-section of the narrowed portion 223c relative to the axial direction can be processed into the desired shape relatively easily by forming the notch 223d by grinding, punching, or the like.

In addition, in the present embodiment shown in Figures 17(a) and 17(b), the cross section of a plane including the boundary line between the narrowing portion 223c and the transition portion 223e is approximately rectangular (long side 5.8 mm, short side (thickness) 1.5 mm), and the cross section of a plane including the boundary line between the transition portion 223e and the rear portion 223f is approximately rectangular (long side 5.8 mm, short side (thickness) 3.2 mm).

In addition, as in the previously described embodiment, the rear side of the connection portion 223b of the nib 202 (rear side of the rear portion 223f) is provided with a cylindrical (large diameter) central portion 224 whose outer surface is clamped in the front-to-rear direction by the retaining member and the front shaft 4, and a cylindrical (small diameter) rear end portion 225 which is connected in a piercing manner to the front end portion of the ink occlusion body 6.

In the pen tip 202 of this embodiment, because the narrowed portion 223c of the connecting portion 223b is a plate-like member having the same thickness as the front portion 223, and because the boundary line between the narrowed portion 223c and the transition portion 223e is parallel to the apex 222 (and further because the boundary line between the transition portion 223e and the rear portion 223f is also parallel to the apex 222), the pen tip 202 can flex more flexibly when writing. Therefore, even if there is undesirable dimensional variation in the pen tip 202 (especially if it is too long in the axial direction), the risk of damage to the pen tip 202 when writing can be significantly reduced.

The nib 202 is also made of a fiber nib (a resin-processed fiber bundle). The nib 202 can also be made of any flexible material that allows ink to flow through it. Specific examples include porous synthetic resins with open cells, felt nibs, brush nibs, and plastic nibs with axial capillary passages.

(Third embodiment)
Fig. 18(a) is a side view of a holding member 303 of a writing implement according to a third embodiment of the present invention, and Fig. 18(b) is a perspective view of the holding member 303. Fig. 19(a) is a schematic perspective view of a case where a straight line is drawn using a ruler with the writing implement according to this embodiment, and Fig. 19(b) is a schematic front view thereof.

18(a) to 19(b), the holding portion 331 of the holding member 303 of this embodiment, similar to the embodiment described using Figures 4(a) to 6(b), has a pair of extension pieces (an inner extension piece 335a and an outer extension piece 335b) that protrude forward (perpendicular to the rear edge 334) from the rear edge 334 of the opening 333 on both short sides of the substantially rectangular cross section of the front portion 23 of the nib 2. The pair of extension pieces 335a, 335b extend in a direction parallel to the extension direction of the front portion 23 of the nib 2, and are designed to come into contact with the paper surface when writing.

The inside of each of the pair of extension pieces 335a, 335b is chamfered, for example, at about 45°, to form an inclined surface 335c that is roughly half of a truncated cone. By providing such an inclined surface 335c, the contact area between each extension piece 335a, 335b and the paper surface during writing is reduced (for example, only a width of about 0.2 mm contacts in a roughly arc-shaped manner (see Figure 19(a))). This increases the pressure applied to the paper surface by extension pieces 335a, 335b, making it easier for extension pieces 335a, 335b to dig into the paper surface. This further effectively prevents handwriting from shifting in an unintended direction.

For example, as shown in Figures 19(a) and 19(b), when drawing a line on paper using a ruler or the like, it is much easier to draw the line as intended.

(Fourth embodiment)
Fig. 20(a) is a side view of a holding member 403 of a writing implement according to a fourth embodiment of the present invention, and Fig. 20(b) is a perspective view of the holding member 403. Fig. 21(a) is a schematic perspective view of a case where a straight line is drawn using a ruler with the writing implement according to this embodiment, and Fig. 21(b) is a schematic front view thereof.

20(a) to 21(b), the holding portion 431 of the holding member 403 of this embodiment, similar to the embodiment described using Figures 4(a) to 6(b), has a pair of extension pieces (an inner extension piece 435a and an outer extension piece 435b) that protrude forward (perpendicular to the rear edge 434) from the rear edge 434 of the opening 433 on both short sides of the substantially rectangular cross section of the front portion 23 of the nib 2. The pair of extension pieces 435a, 435b extend in a direction parallel to the extension direction of the front portion 23 of the nib 2, and are designed to come into contact with the paper surface when writing.

The inner surface of each of the pair of extension pieces 435a, 435b is chamfered by multiple (five in the illustrated example) inclined planes 435c. By providing these multiple inclined planes 435c, the contact area between each extension piece 435a, 435b and the paper surface during writing is reduced (for example, only a linear contact of approximately 0.1 mm width and a length of approximately 1.4 mm (see Figure 21(a))). This increases the pressure applied to the paper surface by the extension pieces 435a, 435b, making it easier for the extension pieces 435a, 435b to dig into the paper surface. This more effectively prevents handwriting from shifting in an unintended direction.

For example, as shown in Figures 21(a) and 21(b), when drawing lines on paper using a ruler or the like, it is much easier to draw the lines as intended.

Fifth Embodiment
FIG. 22( a ) is a side view of a pen tip 502 of a writing implement according to a fifth embodiment of the present invention, and FIG. 22( b ) is a perspective view of the pen tip 502 .

The front portion 523 of the pen tip 502 extends in a linear direction inclined at an acute angle (30° in this embodiment) relative to the axial direction in a side view, similar to the front portion 23 of the pen tip 2 in the previous embodiment. The cross section of the front portion 523 of the pen tip 502 in the extension direction is approximately rectangular (long side 5.0 mm, short side 1 to 3.2 mm). The extension length (the length maintaining the approximately rectangular cross section) is 2.6 mm in this embodiment.

The front portion 523 of the pen tip 502 is sandwiched (partially surrounded) by a pair of extending pieces of a corresponding holding member (not shown), and the top portion 522 of the pen tip 502 protrudes slightly forward (diagonally forward) from the tip of the holding member. The top portion 522 of the pen tip 502 is formed in a substantially straight line in side view and is perpendicular to the extending direction of the front portion 523 of the pen tip 502.

Here, the front portion 523 of the pen tip 502 has a shape that tapers toward the top portion 522, but the top portion 522 of the pen tip 502 does not have a convex curved R-shape, but is a flat surface. As a result, the top portion 522 has a smaller contact area with the paper surface during writing than the top portion 22 of the pen tip 2 in the previously described embodiment. This reduces the amount of "ink puddle" that can form on the paper surface when the pen tip 502 is removed from the paper surface after writing.

In addition, in this embodiment, a notch 523d is provided on the side of the front portion 523 of the pen tip 502 that is inclined at an acute angle relative to the axial direction in side view, so that the front portion 523 of the pen tip 502 has a roughly rectangular parallelepiped shape. Here, in this embodiment, the front end of the notch 523d is located 1.3 mm rearward of the inner end of the apex 522, and the front portion 523 of the pen tip 502 does not have a perfect rectangular parallelepiped shape. In other words, a chamfered portion 522d is provided on the side (inner side) of the tip of the front portion 523 of the pen tip 502 that is inclined at an acute angle in side view.

This effectively prevents breakage and peeling at the tip of the sharply angled (inner) side of the front portion 523 of the nib 502. In particular, when the nib 502 is a fiber nib, the fibers are aligned in the axial direction during the manufacturing process. Therefore, if the tip on the inner side of the front portion 523 of the nib 502 is at a right angle, that portion becomes a collection of short fibers and is extremely brittle. By providing a chamfered portion 522d in that portion, the fibers constituting that portion become longer, significantly reducing brittleness and effectively preventing breakage and peeling. Even when the nib 502 is made of a porous material with open cells, if the tip on the inner side of the front portion 523 of the nib 502 is at a right angle, that portion will be extremely brittle. Even in this case, providing a chamfered portion 522d in that portion significantly reduces the brittleness of that portion, effectively preventing breakage and peeling.

On the other hand, the connecting portion 523b on the rear side of the front portion 523 of the nib 502, which is continuous with the front portion 523 of the nib 502, extends generally in the axial direction. However, the connecting portion 523b is provided with a narrowed portion 523c whose cross section changes in the axial direction. The front end side of the narrowed portion 523c is continuous with the front portion 523 of the nib 502 (the cross section in the extension direction of the front portion 523 of the nib 502 is generally rectangular), and the rear end side of the narrowed portion 523c is continuous with the rear portion 523f, which is generally quadrangular prism-shaped (the cross section in the axial direction is generally rectangular). The change in the cross section of the narrowed portion 523c in the axial direction can be processed into the desired shape relatively easily by forming the notch 523d by grinding, punching, etc.

In addition, as in the previously described embodiment, the rear side of the connection portion 523b of the pen tip 502 (rear side of the rear portion 523f) is provided with a cylindrical (large diameter) central portion 524 whose outer surface is clamped in the front-to-rear direction by the retaining member and the front shaft 4, and a cylindrical (small diameter) rear end portion 525 which is connected in a piercing manner to the front end portion of the ink absorbing body 6.

The pen tip 502 is not limited to a fiber pen tip (a resin-processed fiber bundle) or a porous synthetic resin with open cells, but may also be a felt pen tip, a brush pen tip, a plastic pen tip with an axial capillary passage, etc.

DESCRIPTION OF SYMBOLS 1 Writing implement 2, 2' Pen tip 22 Top 23 Front portion 23b, 23b' Connecting portion 23c Narrowed portion 23d Notch 24 Central portion 25 Rear end portion 3, 3' Retaining member 31 Retaining portion 33 Opening 34 Rear edge portion 35 Extension piece 35a Inner extending piece 35b Outer extending piece 36 First abutting wall portion 4 Front shaft 41 Second abutting wall portion 42 Third abutting wall portion 43 Vertical rib 5 Rear shaft 51 Second abutting wall portion 6 Ink occluding body 101 Writing implement 102 Pen tip 122 Top 123 Front portion 103 Retaining member 131 Retaining portion 133 Opening 134 Rear edge portion 135 Extension piece 202 Pen tip 222 Top 223 Front portion 223b Connecting portion 223c Narrowed portion 223d Notch 223e Transition section 223f Rear section 224 Central section 225 Rear end section 303 Holding member 331 Holding section 333 Opening section 334 Rear end edge 335a Inwardly extending piece 335b Outwardly extending piece 335c Inclined surface 403 Holding member 431 Holding section 433 Opening section 434 Rear end edge 435a Inwardly extending piece 435b Outwardly extending piece 435c Inclined plane 502 Pen tip 522 Top part 523 Front part 523b Connection part 523c Squeezed part 523d Notch 523f Rear part 524 Center part 525 Rear end part

Claims (8)

The pen tip and
a holding member for holding the pen tip;
A writing instrument comprising:
The front part of the pen tip extends in a linear direction inclined at an acute angle with respect to the axial direction in a side view,
A cross section of the front part of the pen tip relative to the extension direction has a substantially rectangular shape,
the holding member has a holding portion that surrounds at least a portion of the front portion of the pen tip,
The holding portion has openings on both long sides of the substantially rectangular cross section of the front portion of the pen tip,
The tip of the pen tip is formed in a substantially straight line in a side view and is substantially perpendicular to the extension direction of the front part of the pen tip,
a rear edge of the opening is formed in a substantially straight line in a side view and is substantially parallel to the top of the pen tip;
The holding portion is characterized in that it has an extension piece that extends in a direction approximately parallel to the extension direction of the front part of the pen tip on the short side of the approximately rectangular cross section of the front part of the pen tip, which is the inner short side when viewed from the side. The writing instrument described in claim 1, characterized in that the holding portion has a pair of extension pieces extending in a direction approximately parallel to the extension direction of the front part of the pen tip on both short sides of the approximately rectangular cross section of the front part of the pen tip. 3. The writing implement according to claim 1, wherein a connecting portion of the pen tip, which is continuous with the front portion at a rear side of the front portion, extends generally in the axial direction. 4. The writing implement according to claim 3, wherein the connecting portion of the pen tip is provided with a narrowed portion whose cross section changes relative to the axial direction. 5. The writing implement according to claim 1, wherein the width of the opening is greater than the width of the long side of the substantially rectangular cross section of the front part of the pen tip. Further, a barrel connected to the holding member is provided,
a rear portion of the holding member attached to a front portion of the barrel;
a first abutment wall portion is formed on an inner surface of the holding member,
A second abutment wall portion is formed on the inner surface of the barrel,
6. The writing implement according to claim 1, wherein the outer surface of the pen tip is sandwiched in the front-rear direction between the first abutment wall portion and the second abutment wall portion. 7. A writing instrument according to claim 1, wherein the nib is one of a fiber nib, a felt nib, a nib made of a porous material having open cells, and a plastic nib having an axial capillary passage. 8. The writing implement according to claim 1, wherein a chamfer is provided at the tip of the front part of the pen tip on the side that is inclined at an acute angle in a side view.