Writing implements and writing implement sets

Abstract

To provide a writing tool that can freely change a width of a drawing line by writing pressure, and stores an ink in which colored resin fine particles having sufficient line-density are used as a colorant, thereby the ink can respond to a fine shaft sign pen or marking pen, and is excellent in stability even if an amount of an included dye is increased.SOLUTION: A writing tool comprises: a first writing part 20 that is housed on a tip side inside a shaft barrel 10 and guides an ink from an ink storage part 15 by capillary force; and a second writing part 30 that is attached to the tip of the shaft barrel 10, is penetrated through by the first writing part 20, and has a protruded tip, wherein the first writing part 20 moves backward at the tip of the second writing part 30 by the writing pressure. The ink contains: colored resin fine particles containing a total polymer component containing a monomer containing at least a cyclohexyl (meth)acrylate monomer and a crosslinking agent, and a dye component consisting of one of a basic dye and an oil-soluble dye; a water-soluble organic solvent; and water.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a writing instrument and a writing instrument set including the same. [Background technology]

[0002] The following Patent Document 1 describes a writing instrument comprising a barrel, an ink supply core housed inside the barrel and capable of guiding ink by capillary force, and a core surrounding member covering the outer circumference of the ink supply core, with the ink supply core and a portion of the core surrounding member exposed from the tip of the barrel, the writing instrument further comprising a displacement means capable of relatively changing the axial positional relationship between the ink supply core and the core surrounding member, and the displacement means moves the ink supply core backward relative to the core surrounding member, thereby allowing the tip of the ink supply core and the tip of the core surrounding member to simultaneously come into contact with a writing surface.

[0003] In this way, in a writing instrument that houses a core peripheral member with an ink supply core penetrating it inside the barrel, the ink that is guided to the tip by the capillary force of the ink supply core often rises up into the barrel through the gap between the ink supply core and the core peripheral member. For example, if the barrel is made of a material that allows the inside to be seen, the ink that has risen up into the barrel will be visible, damaging the appearance. Moreover, dried ink may clog the air replacement hole that connects the inside and outside of the barrel, hindering the replacement of ink with air and causing ink to stop being ejected.

[0004] Meanwhile, inks for writing instruments have been known which use coloring materials also called pseudo-pigments, which are produced by dyeing a resin emulsion having a specific polymer structure with a dye.

[0005] For example, there are known: 1) an aqueous dispersion of colored resin microparticles for aqueous inks prepared by emulsion polymerization of a vinyl monomer having an acidic functional group in which a water-soluble basic dye is dissolved in the presence of a polymerizable surfactant (see, for example, Patent Document 2); and 2) an aqueous ink composition for writing instruments using a dispersion of colored resin microparticles for aqueous inks in which colored resin microparticles composed of at least a carboxyl group-containing vinyl monomer (A) having a solubility in water of 10 mass% or less as an acidic functional group, an ester monomer (B) of acrylic acid or methacrylic acid with a linear or cyclic alcohol having 2 to 18 carbon atoms, and a basic dye or an oil-soluble dye are dispersed in water (see, for example, Patent Document 3).

[0006] However, the aqueous ink for writing instruments using the dispersion of colored resin microparticles for aqueous inks described in Patent Documents 2 and 3 as a coloring material had a limited amount of dye that could be encapsulated. Therefore, the density of the drawn lines tended to be slightly insufficient. On the other hand, if the amount of dye added during the synthesis of the colored resin microparticles was increased, polymerization was inhibited and stable colored resin microparticles could not be obtained. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] JP 2016-026930 A [Patent Document 2] Japanese Patent Application Publication No. 10-259337 [Patent Document 3] JP 2016-196623 A Summary of the Invention [Problem to be solved by the invention]

[0008] An aspect of the present disclosure aims to provide a writing instrument that allows the width of the drawn line to be freely changed by the writing pressure, and is compatible with thin-barreled felt-tip pens or marking pens, and a writing instrument set equipped with the same.

[0009] Further, in view of the problems and the like of the conventional technology described above, the aspects of the present disclosure are intended to solve these problems, and have an object to provide a writing instrument that stores ink that is highly stable and has sufficient line density, even when the amount of dye contained therein is large. [Means for solving the problem]

[0010] A writing instrument according to a first aspect of the present disclosure includes a barrel; an ink storage section for storing ink inside the barrel; a first writing part that is accommodated in the barrel at the tip side and guides the ink from the ink storage part by capillary force; a second writing part attached to the tip of the barrel, through which the first writing part passes and from which the tip of the first writing part protrudes; having The first writing part is moved backward at the tip of the second writing part by writing pressure, The ink is colored resin fine particles including at least a total polymer component including a monomer including at least a cyclohexyl (meth)acrylate monomer and a crosslinking agent, and a dye component including one of a basic dye and an oil-soluble dye; Contains a water-soluble organic solvent and water, The proportion of the cyclohexyl (meth)acrylate monomer in the total polymer component is 30 mass% or more, The dye component is contained in an amount of 15 parts by mass or more per 100 parts by mass of the total polymer components.

[0011] In addition, it is preferable that the protruding dimension of the first writing part from the tip of the second writing part is 0.05 to 0.7 mm when not writing. Moreover, it is preferable that the second writing part has a tip opening from which the tip of the first writing part protrudes, and the value obtained by subtracting the outer diameter of the flow path from the inner diameter of the tip opening is 0.5 mm or less, preferably less than 0. Note that this numerical value can be a negative number. Furthermore, under the same writing load, the value obtained by dividing the line width at a writing angle of 60° to the writing surface by the line width at a writing angle of 90° to the writing surface is preferably 0.67 or more and less than 1.5, more preferably 0.9 or more and less than 1.1. If this value is less than 0.67 or 1.5 or more, the line width will vary depending on the writing conditions, making the pen difficult to use.

[0012] A writing instrument set according to a second aspect of the present disclosure is a writing instrument set comprising the writing instrument of the first aspect and a case for storing the writing instrument, The case is a storage section for storing the writing instrument so that the writing instrument can be taken in and out through a rectangular opening; A hinge portion provided on one of the long sides of the opening; Two opening edges which are both short sides of the opening; a movable portion that is connected to the storage portion via the hinge portion and is rotatable between a closed position and an open position with respect to the opening portion; two abutment edges in the movable portion that abut against the two opening edges, respectively, in the closed position; a support piece protruding from an inner surface side of the opening edge toward the movable part; An engagement hole formed in the support piece; a locking edge which is a side of the support piece facing the hinge portion; an engaging projection that protrudes inward near the abutting edge of the movable portion, that fits into the engaging hole in the closed position, and that abuts against the locking edge in the open position; The present invention is characterized by comprising:

[0013] A writing instrument set according to a third aspect of the present disclosure is a writing instrument set comprising the writing instrument of the first aspect and a case for storing the writing instrument, The case is a storage section for storing the writing instrument so that the writing instrument can be taken in and out through a rectangular opening; A hinge portion provided on one of the long sides of the opening; Two opening edges which are both short sides of the opening; a movable portion that is connected to the storage portion via the hinge portion and is rotatable between a closed position and an open position with respect to the opening portion; two abutment edges in the movable portion that abut against the two opening edges, respectively, in the closed position; a support piece protruding from an inner surface side of the opening edge toward the movable part; a locking edge which is a side of the support piece facing the hinge portion; a fitting protrusion protruding outwardly from the vicinity of the locking edge of the support piece; an engaging projection that protrudes inward near the abutment edge of the movable portion and abuts against the locking edge in the open position; an engagement hole formed in the vicinity of the contact edge of the movable portion, into which the engagement projection is fitted when the movable portion is in the closed position; The present invention is characterized by comprising: Effect of the Invention

[0014] Since each aspect of the present disclosure is configured as described above, it is possible to freely change the width of the drawn line by changing the writing pressure even when using a thin-barreled felt-tip pen or marking pen.

[0015] Furthermore, according to each aspect of the present disclosure, there is provided a writing instrument that stores ink that uses colored resin microparticles as a coloring material, which has excellent stability and sufficient line density even when the amount of dye contained therein is large. [Brief description of the drawings]

[0016] [Figure 1A] 1 is a front view showing the overall configuration of a writing instrument according to a first embodiment. [Figure 1B] FIG. 1B is an α-α cross-sectional view of FIG. 1A. [Diagram 2] This is an enlarged view of a main part of FIG. 1B. [Figure 3A] FIG. 2 is a perspective view showing a grip member of the writing instrument according to the first embodiment. [Figure 3B] 1 is a side view showing a grip member of a writing instrument according to a first embodiment. [Figure 3C] FIG. 3C is a β-β cross-sectional view of FIG. 3B. [Figure 4A] FIG. 2 is a perspective view showing a cap of the writing instrument according to the first embodiment. [Figure 4B] This is a γ-γ cross-sectional view of Figure 4A. [Figure 4C] FIG. 4B is a cross-sectional view of FIG. 4A along line δ-δ. [Figure 5A] 1 is a plan view showing a head portion of a cap in a writing instrument according to a first embodiment. FIG. [Figure 5B] FIG. 4B is a bottom view showing the insertion portion of the cap in the writing instrument according to the first embodiment. [Figure 5C] 1 is a side cross-sectional view showing a state in which a tip barrel is inserted into a cap in a writing instrument according to a first embodiment. FIG. [Figure 6A] FIG. 2 is a perspective view showing the tail plug of the writing instrument according to the first embodiment. [Figure 6B] FIG. 2 is a side view showing the tail plug of the writing instrument according to the first embodiment. [Figure 6C] FIG. 6C is a cross-sectional view of FIG. 6B along ε-ε. [Figure 7A] 2 is a perspective view of a second writing part of the writing instrument according to the first embodiment. FIG. [Figure 7B] 3 is a side view of a second writing part of the writing instrument according to the first embodiment. FIG. [Figure 7C] FIG. 7C is a cross-sectional view of FIG. 7B along line ζ-ζ. [Figure 8A] 13 is a side view showing a modified example of the second writing part of the writing instrument according to the first embodiment. FIG. [Figure 8B] FIG. 8B is a cross-sectional view taken along the line η-η of FIG. 8A. [Figure 9A] 1 is a cross-sectional view showing a state before operation of a first writing part and a second writing part in a writing instrument according to a first embodiment. FIG. [Figure 9B] 1 is a cross-sectional view showing a state in which a first writing part and a second writing part of a writing instrument according to a first embodiment are in operation. [Figure 10A] 2 is an enlarged cross-sectional view showing the tip portion of the writing implement according to the first embodiment. FIG. [Figure 10B]10B is a θ-θ cross-sectional view showing an example of the first writing part of FIG. 10A. FIG. [Figure 10C] Another example of the first writing part of FIG. 10A is shown in a cross-sectional view similar to FIG. 10B. [Figure 11A] FIG. 11 is a perspective view showing the overall configuration of a writing instrument according to a second embodiment. [Figure 11B] FIG. 11 is a front view showing the overall configuration of a writing instrument according to a second embodiment. [Figure 11C] FIG. 11C is a cross-sectional view of FIG. 11B. [Figure 12] FIG. 11D is an enlarged view of a main part of FIG. [Figure 13A] FIG. 11 is a front view of a grip member of a writing instrument according to a second embodiment. [Figure 13B] FIG. 13B is a front perspective view of the gripping member of FIG. 13A. [Figure 13C] FIG. 13B is a rear perspective view of the gripping member of FIG. 13A. [Figure 13D] FIG. 13B is a plan view of the gripping member of FIG. 13A. [Figure 13E] FIG. 13B is a bottom view of the gripping member of FIG. 13A. [Figure 13F] FIG. 13B is a κ-κ cross-sectional view of FIG. 13A. [Figure 14A] FIG. 11 is a perspective view of a barrel of a writing instrument according to a second embodiment. [Figure 14B] FIG. 14B is a front view of the barrel of FIG. 14A. [Figure 14C] FIG. 14B is a plan view of the barrel of FIG. 14A. [Figure 14D] FIG. 14B is a bottom view of the barrel of FIG. 14A. [Figure 14E] FIG. 14C is a λ-λ cross-sectional view of FIG. 14B. [Figure 15A] FIG. 14B is a perspective view of a modified example of the barrel shown in FIG. 14A. [Figure 15B] FIG. 15B is a front view of the barrel of FIG. 15A. [Figure 15C] FIG. 15B is a plan view of the barrel of FIG. 15A. [Figure 15D] FIG. 15B is a bottom view of the barrel of FIG. 15A. [Figure 15E] FIG. 15B is a μ-μ cross-sectional view of FIG. 15A. [Figure 16A]FIG. 11 is a front view of the tail plug of a writing instrument according to a second embodiment. [Figure 16B] FIG. 16B is a ν-ν cross-sectional view of FIG. 16A. [Figure 17A] This is a further enlargement of the tip portion of FIG. [Figure 17B] A modification of FIG. 17A is shown. [Figure 18A] FIG. 1 is a front, upper perspective view of a first embodiment of a case capable of storing a writing instrument. [Figure 18B] 1 is a rear perspective view from above of a first embodiment of a case capable of storing a writing instrument; [Figure 18C] 1 is a front, bottom perspective view of a first embodiment of a case capable of storing a writing instrument; [Figure 18D] 1 is a rear perspective view from below of a first embodiment of a case capable of storing a writing instrument. FIG. [Figure 19A] FIG. 2 is a front view of the case of the first embodiment. [Figure 19B] FIG. 4 is a rear view of the case of the first embodiment. [Figure 19C] FIG. 1 is a plan view of a case according to a first embodiment; [Figure 19D] FIG. 4 is a bottom view of the case of the first embodiment. [Figure 19E] FIG. 4 is a left side view of the case of the first embodiment. [Figure 19F] FIG. 4 is a right side view of the case of the first embodiment. [Figure 20] 1 is a front top perspective view showing a state in which a movable part of a case of the first embodiment is in an open position relative to an opening. FIG. [Figure 21] FIG. 2 is a front bottom perspective view showing a state in which the case of the first embodiment is unfolded. [Figure 22] FIG. 2 is a front top perspective view of a cover portion of a case according to the first embodiment. [Diagram 23] FIG. 2 is a front bottom perspective view of a movable part of the case of the first embodiment. [Figure 24] 1 is a front bottom perspective view showing a state in which a movable part of a case of the first embodiment has been rotated to place the case in an upright position. FIG. [Diagram 25]25 is an enlarged view of the state in which the locking edge and the engagement projection are locked in the state shown in FIG. [Figure 26] FIG. 1 is a front top perspective view of a writing instrument set in which a writing instrument is combined with a case according to a first embodiment. [Figure 27A] FIG. 13 is a front, upper perspective view of a second embodiment of a case capable of storing a writing instrument. [Figure 27B] FIG. 13 is a rear perspective view from above of a second embodiment of a case capable of storing a writing instrument. [Figure 27C] FIG. 13 is a front, bottom perspective view of a case according to a second embodiment capable of storing a writing instrument. [Figure 27D] FIG. 11 is a rear perspective view from below of a second embodiment of a case capable of storing a writing instrument. [Figure 28A] FIG. 11 is a front view of the case of the second embodiment. [Figure 28B] FIG. 11 is a rear view of the case of the second embodiment. [Figure 28C] FIG. 11 is a plan view of a case according to the second embodiment. [Figure 28D] FIG. 11 is a bottom view of the case of the second embodiment. [Figure 28E] FIG. 11 is a left side view of the case of the second embodiment. [Figure 28F] FIG. 11 is a right side view of the case of the second embodiment. [Figure 29] 13 is a front top perspective view showing a state in which a movable part of a case of the second embodiment is in an open position relative to an opening. FIG. [Diagram 30] FIG. 13 is a front bottom perspective view showing a state in which the case of the second embodiment is unfolded. [Diagram 31] 13 is a front top perspective view of a cover portion of a case according to a second embodiment. FIG. [Diagram 32] 13 shows a front bottom perspective view of a movable part of a case of the second embodiment. FIG. [Diagram 33] 13 is a front bottom perspective view showing a state in which the movable part of the case of the second embodiment has been rotated to place the case in an upright position. FIG. [Diagram 34] 34 is an enlarged view of the state in which the locking edge and the engagement projection are locked in the state shown in FIG. [Diagram 35]FIG. 13 is a front top perspective view of a writing instrument set in which a writing instrument is combined with a case of a second embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0017] Hereinafter, with reference to the drawings, a thin-barreled felt-tip pen or marking pen will be described as an example of the writing instrument 1 according to this embodiment. In each drawing, the "front" of the writing instrument 1 and its components refers to the direction of the tip of the writing instrument 1, the "rear" refers to the opposite direction, the "axial direction" refers to the direction of the axis that runs from the front to the rear of the barrel 10, and the "transverse direction" refers to the direction perpendicular to the axial direction. Also, the symbols commonly used in each drawing represent the same configuration or member even if not specifically mentioned in the description of each drawing.

[0018] <Overall configuration of the first embodiment> As shown in Fig. 1A, the writing instrument 1 according to the first embodiment comprises a barrel 10 in which a smaller-diameter front barrel 11 and a larger-diameter rear barrel 12 are integrally formed (see Fig. 2), and a second writing part 30 attached to the front side of the front barrel 11. As shown in Fig. 1B, an ink storage part 15 in which ink is stored is housed inside the rear barrel 12. An air replacement port 11E is provided near the tip of the front barrel 11, allowing air to flow between the inside and outside of the barrel 10. The ink stored in this ink storage part 15 will be described later. The first writing part 20 penetrates the second writing part 30. The tip of the first writing part 20 protrudes from the tip of the second writing part 30. The rear end of the first writing part 20 extends until it penetrates the front end of the ink storage part 15. Although not shown in FIG. 1A, cap 50 shown in FIGS. 4A to 4C is attached to front barrel 11 shown in FIG. 1A.

[0019] (Structure of the barrel) 1B, as described above, barrel tube 10 has front barrel 11 and rear barrel 12. A front opening 13 opens at the front end of front barrel 11, and a rear opening 14 opens at the rear end of rear barrel 12. A tail plug 60 is press-fitted into rear opening 14. As shown in FIG. 3A, the outer shape of the barrel 10 is formed such that the cross section in the transverse direction is a generally rounded rectangle.

[0020] As shown in FIG. 2, the rear shaft 12 is integrally formed with a front grip portion 12A on the front side covered with a grip member 40 described later, and a rear grip portion 12B on the rear side. Furthermore, at a boundary 12C between front grip portion 12A and rear grip portion 12B, there is a step that narrows in diameter toward the front, so that front grip portion 12A is thinner than rear grip portion 12B. A plurality of axially elongated rectangular slots 12D are formed in a portion of the outer circumferential surface of the front grip portion 12A. Locking pieces 44 protruding from the inner surface of the grip member 40 (described later) fit into the slots 12D. Further, front end 12E of front grip portion 12A is formed with a surface whose transverse cross section is shaped like a convex arc, and front barrel 11 formed integrally in front of it is thinner than this end 12E. Furthermore, a flange 62 of a tail plug 60 contacts the rear end edge of the rear body 12 (see FIG. 1B).

[0021] As shown in FIG. 2, front barrel 11 has, from the rear end, base portion 11A, reduced diameter portion 11B, tip portion 11C, and locking surface 11D. The base portion 11A is a portion that extends forward with a constant thickness from the front end portion 12E of the front grip portion 12A. As shown in Fig. 2 and Figs. 3A-C, protrusions are formed on each side of the middle portion of the base portion 11A along a direction intersecting the axial direction. These protrusions are referred to as locking protrusions 11A1. In this embodiment, a total of four locking protrusions 11A1 are provided. The reduced diameter portion 11B is a portion that tapers and extends forward from the front end of the base portion 11A. The tip portion 11C is a portion that extends forward with a constant thickness from the front end of the reduced diameter portion 11B. The locking surface 11D is the tip edge of the tip portion 11C, and is in contact with an engagement piece 33A of an engagement portion 33 of the second writing part 30, which will be described later.

[0022] (Grip member) As shown in FIGS. 3A to 3C, the gripping member 40 is formed in a cylindrical shape having a substantially square cross section as a whole, and has a front opening 42 that opens to the front and a rear opening 43 that opens to the rear. The locking pieces 44 are formed as axially long protrusions that protrude inward on the inside of the grip member 40. The grip member 40 is attached to the rear axle 12 by fitting these locking pieces 44 into multiple slots 12D provided on the outer periphery of the front grip portion 12A of the rear axle 12. Edge portion 42A is formed at the end of front opening 42. The inner surface of edge portion 42A is formed with a concave arc shape in cross section to correspond to the convex arc shape of the cross section of end 12E of front grip portion 12A. Front opening 42 is formed with a size that allows root portion 11A of front barrel 11 to fit therein. An end face 43A is formed at the end of the rear opening 43, and is in contact with a stepped surface of a boundary portion 12C of a rear grip portion 12B of the rear body 12. In addition, as shown in Figures 3A and 3B, the gripping member 40 may be given a color different from that of the barrel 10, and the color may be, for example, similar to the color of the ink stored in the ink storage section 15. The barrel 10 and the gripping member 40 can be formed by two-color molding, for example.

[0023] (cap) The cap 50 has a cap outer cylinder 51 and a cap inner cylinder 52, as shown in FIGS.

[0024] 4A, the cap outer cylinder 51 is formed in a cylindrical shape as a whole, and has openings at the front and rear. Of these, the rear opening is referred to as a rear opening 54. The outer peripheral surface of this cap outer cylinder 51 is formed in a generally rounded quadrangle in cross section in the transverse direction, similar to the outer peripheral surface of the barrel 10. As shown in Figures 4A-C and 5A-C, the cap inner tube 52 is formed in a cylindrical shape with a closed front end and an open rear end. The cap inner tube 52 is housed in the front half of the inside of the cap outer tube 51, and the open rear end portion is connected to the inner circumferential surface of the cap outer tube 51 at a substantially middle portion by connecting portions 52A that are evenly spaced discontinuously. A plurality of through holes 53A are formed between these connecting portions 52A. In addition, the rear end edge of the cap inner tube 52 is a discontinuous edge 52B that is divided by the connecting portions 52A. In this embodiment, the connecting portions 52A and the discontinuous edges 52B are formed in six places each.

[0025] The closed tip portion of the cap inner cylinder 52 is flush with the tip portion of the cap outer cylinder 51, and its periphery is surrounded by a continuous circumferential groove 53. The circumferential groove 53 communicates with the rear half of the interior of the cap outer cylinder 51 via the through hole 53A.

[0026] From rear opening 54, front barrel 11 (see FIGS. 1A and 1B and FIGS. 3A to 3C) described above is inserted. Locking projections 55 are multiple projections formed near the rear end of the inner surface of cap outer cylinder 51, intersecting the axial direction, and are locked to each other by elastically deforming from the front to the rear to overcome locking projections 11A1 (see Figs. 2 and 3A-C) provided on front barrel 11. In this way, cap 50 is attached to barrel tube 10. In this embodiment, a total of four locking projections 55 are provided corresponding to the rounded side surfaces of cap outer cylinder 51, as shown in FIG. 4A.

[0027] 4B and 4C, the guide piece 56 is formed as an inclined protrusion that connects the connecting portion 52A to the inner surface of the cap outer cylinder 51. In the present embodiment, a total of six guide pieces 56 are equally spaced.

[0028] As shown in FIG. 5C, when tip barrel 11 is inserted from rear opening 54 of cap 50 while sliding against its inner peripheral edge 54A, these multiple guide pieces 56 guide reduced diameter portion 31 of second writing portion 30 and tip end 23 of first writing portion 20, thereby preventing collision of reduced diameter portion 31 or tip end 23 with discontinuous edge 52B and preventing damage.

[0029] (tail plug) 6A to 6C, tail plug 60 is formed into a cylindrical shape as a whole, and has an insertion portion 61, a flange portion 62, and a head portion 63. The tip of insertion portion 61 forms a tail portion 64. The insertion portion 61 is inserted into the interior of the rear axle 12 from a rear opening 14 of the rear axle 12 in the barrel 10, and closes the rear opening 14 (see FIG. 1B). The flange portion 62 fits tightly against the end face of the rear opening 14 to seal the inside of the rear body 12 and isolate the inside of the rear body 12 from the outside air. The head portion 63 is formed so as to extend rearward from the flange portion 62, and the cap 50 can be attached thereto when writing.

[0030] The shape of the tail plug 60 is such that the insertion portion 61 and the head portion 63 are formed to have a circular cross section in the transverse direction, but the flange portion 62 is formed to have a rounded rectangular cross section similar to the cross section of the barrel 10. In other words, the shapes of the flange portion 62 and the rear barrel 12 are matched so that they have the same shape when the tail plug 60 is inserted into the rear opening 14 of the barrel 10.

[0031] It should be noted that another writing part (not shown) can be attached in place of the tail plug 60. Here, by making the outer diameter of the portion where the other writing part is inserted into the rear barrel 12 the same shape as the insertion part 61 of the tail plug 60, the barrel 10 can be used both for a writing instrument 1 having a writing tip at only one end as in this embodiment, and for a writing instrument having writing tips at both ends.

[0032] (ink storage section) Ink storage section 15 shown in FIG. 1B is a cylindrical batting made of polyester fiber material that stores ink, and is housed inside rear barrel 12 of barrel tube 10. In addition, as shown in FIG. 2, the front end of ink storage section 15 is located inside front grip portion 12A of rear barrel 12, slightly forward of boundary portion 12C, and is in contact with multiple ribs 12A1 (see FIG. 3C) formed in the axial direction on the inner surface of front grip portion 12A. On the other hand, the rear end of the ink storage section 15 is located in a position where it comes into contact with a tail section 64 of a tail plug 60 which fits into the rear barrel 12 . As a result, the ink storage section 15 is sandwiched and fixed between the rib 12A1 of the front grip section 12A and the tail section 64 of the tail plug 60, as shown in FIG. 1B.

[0033] (ink) The ink of this embodiment is stored in an immersed state in the ink storage section 15, and contains uncolored resin microparticles containing at least a monomer containing at least a cyclohexyl (meth)acrylate monomer, a total polymer component containing a crosslinking agent, and a dye component consisting of either a basic dye or an oil-soluble dye, a water-soluble organic solvent, and water. The proportion of the cyclohexyl (meth)acrylate monomer in the total polymer components is 30% by mass or more. Furthermore, the amount of the dye component is 15 parts by mass or more per 100 parts by mass of the total polymer components.

[0034] The (meth)acrylate cyclohexyl monomer contained in all polymer components used in this embodiment has the advantage that stable colored resin microparticles with excellent color development and sufficient line density can be obtained even if the amount of dye contained therein is increased. In addition, the obtained colored resin microparticles have the advantage that sufficient line density can be obtained. Here, "all polymer components" includes all types of monomers and crosslinking agents that are the raw materials for the final polymer, and one of the monomers is the above-mentioned (meth)acrylate cyclohexyl monomer. Note that "(meth)acrylate cyclohexyl monomer" refers to the (meth)acrylate cyclohexyl used as a monomer. In the present disclosure, the term "(meth)acrylic acid" refers to "acrylic acid and / or methacrylic acid." Therefore, "cyclohexyl (meth)acrylate monomer" refers to "cyclohexyl acrylate monomer and / or cyclohexyl methacrylate monomer." Cyclohexyl (meth)acrylate monomer is produced by a known production method. Examples of the known production method include an esterification method in which (meth)acrylic acid and cyclohexanol are esterified using a catalyst such as an inorganic acid, an organic sulfonic acid, or a strongly acidic ion exchange resin, and an ester exchange method in which an organometallic compound containing titanium, tin, or the like is used as a catalyst.

[0035] In this embodiment, all of the monomers may be the cyclohexyl (meth)acrylate monomers described above, or other types of monomers may be included in the total polymer composition, such as hydrophobic vinyl monomers and / or aqueous monomers. As the hydrophobic vinyl monomer, for example, at least one monomer such as esters of (meth)acrylic acid other than the above-mentioned cyclohexyl (meth)acrylate monomer, styrene, methylstyrene, and other styrenes can be used.Specific examples include at least one of methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, isopropyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, t-butyl (meth)acrylate, hexyl (meth)acrylate, octyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, lauryl (meth)acrylate, palmityl (meth)acrylate, stearyl (meth)acrylate, behenyl (meth)acrylate, styrene, and methylstyrene, that is, any one or a mixture of two or more of these. Examples of aqueous monomers that can be used include at least one of glycerin monomethacrylate, sodium 2-sulfoethyl methacrylate, polyethylene glycol monomethacrylate, polypropylene glycol monomethacrylate, polyethylene glycol-propylene glycol monomethacrylate, polyethylene glycol-tetramethylene glycol-monomethacrylate, and propylene glycol-polybutylene glycol-monomethacrylate, i.e., a mixture of any one or more of these.

[0036] Examples of the basic dyes used in this embodiment include diarylmethane dyes and triarylmethane dyes, quinoneimine dyes such as azines (including nigrosine), oxazines and thiazines, xanthene dyes, triazole azo dyes, thiazole azo dyes, benzothiazole azo dyes and azo dyes, methine dyes such as polymethine, azomethine and azamethine, anthraquinone dyes and phthalocyanine dyes. At least one of these basic dyes, that is, any one of these or a mixture of two or more of these, can be used. Of these, water-soluble basic dyes are preferable.

[0037] Specific basic dyes that can be used include, for example, CI Basic Yellow 1, 2, 9 and 80, CI Basic Orange 1, 2, 7 and 34, CI Basic Red 1, 2, 3 and 53, CI Basic Violet 1, 2, 3 and 39, CI Basic Blue 1, 2, 5 and 88, CI Basic Green 1, 4, 6 and 10, CI Basic Brown, 1, 2, 4 and 15, and CI Basic Black 1, 2, 7 and 8. Examples of these commercially available products include Aizen Cathilon Yellow GLH (Hodogaya Chemical Co., Ltd.), Aizen Cathilon Red BLH (Hodogaya Chemical Co., Ltd.), Aizen Cathilon Red RH (Hodogaya Chemical Co., Ltd.), Diacryl Supra Brilliant Red 2G (Mitsubishi Chemical Co., Ltd.), and Sumiacryl Red B (Sumitomo Chemical Co., Ltd.), Aizen Cathilon Turquoise Blue LH (Hodogaya Chemical Co., Ltd.), Diacryl Supra Brilliant Green 2GL (Mitsubishi Chemical Co., Ltd.), Janus Brown R (Nihon Kagaku Co., Ltd.), and Aizen Cathilon Brown GH (Hodogaya Chemical Co., Ltd.).

[0038] Examples of the oil-soluble dyes used in the present embodiment include commercially available monoazo dyes, disazo dyes, metal complex monoazo dyes, anthraquinone dyes, phthalocyanine dyes, and triarylmethane dyes. Salt-forming oil-soluble dyes in which the functional group of an acid dye or basic dye is replaced with a hydrophobic group can also be used.

[0039] Specific examples of oil-soluble dyes that can be used include CI Solvent Yellow 114 and 116, CI Solvent Orange 67, CI Solvent Red 122 and 146, CI Solvent Blue 5, 36, 44, 63, 70, 83, 105 and 111, and CI Solvent Black 3, 7, 27 and 29. Commercially available products of these include SBN Blue 701 (Hodogaya Chemical Industry Co., Ltd.), Oil Blue 650 (Orient Chemical Industry Co., Ltd.), Saninyl Blue GLS (Clariant) and SOC-1-0100 (Orient Chemical Industry Co., Ltd.), as well as Oil Black 860, Oil Pink 314, Oil Yellow 3G, Varifast Pink 2310N, Varifast Red 3312, Varifast Yellow CGHNnew, Varifast Yellow 1108 and Varifast Black 3830 (all Orient Chemical Industry Co., Ltd.).

[0040] The colored resin microparticles of this embodiment can be produced as a dispersion liquid in a state of being dispersed in water. The production method thereof is, for example, by dissolving the above-mentioned basic dye or oil-soluble dye in the above-mentioned cyclohexyl (meth)acrylate monomer or in a mixed monomer containing the above-mentioned cyclohexyl (meth)acrylate monomer and other hydrophobic vinyl monomers or aqueous monomers, and using ammonium persulfate, potassium persulfate, hydrogen peroxide, or the like alone or in combination with a reducing agent as a polymerization initiator, and further using triallyl isocyanurate, triallyl isocyanurate, polyethylene glycol dimethacrylate, polypropylene glycol dimethacrylate, pentaerythritol acrylate, ditrimethylolpropane acrylate, dipentaerythritol acrylate, methoxylated bisphenol A methacrylate, pentaerythritol methacrylate, ditrimethylolpropane methacrylate, dipentaerythritol methacrylate, or ethoxylated polyglycerin methacrylate, or, if necessary, polyoxyethylene- It can be produced by emulsion polymerization using a polymerizable surfactant (emulsifier) ​​such as 1-(allyloxymethyl)-alkyl ether ammonium sulfate, ether sulfate, polyoxyethylene nonylpropenyl phenyl ether ammonium sulfate, polyoxyethylene nonylpropenyl phenyl ether, ammonium polyacrylate, styrene-maleic acid copolymer ammonium, polyoxyethylene alkyl ether, polyoxyethylene styrenated phenyl ether, polyoxyethylene polyoxypropylene glycol, polyoxyalkylene decyl ether, polyoxyethylene tridecyl ether, alkylbenzene sulfonate, dioctyl sulfosuccinate, sodium lauryl sulfate, polyoxyethylene alkyl ether phosphate, polyoxyethylene styrenated phenyl ether phosphate, polyoxyethylene styrenated phenyl ether sulfate, or polyoxyethylene alkyl ether sulfate. In the above, dyeing with a basic dye or oil-soluble dye is performed simultaneously with polymerization, but dyeing may be performed by dissolving a basic dye or oil-soluble dye after polymerization. By using the above-mentioned crosslinking agent, the heat resistance, mechanical properties, hydrolysis resistance and weather resistance of the colored resin particles are improved.

[0041] In this embodiment, during the emulsion polymerization, an appropriate amount of dicyclopenta(ten)yl (meth)acrylate monomer or the like may be further mixed with the cyclohexyl (meth)acrylate monomer or the like to perform emulsion polymerization. When this dicyclopenta(ten)yl (meth)acrylate monomer is further mixed and then emulsion polymerization is performed, the stability is not easily impaired even if the water in the dispersion evaporates, and a dispersion of colored resin microparticles for aqueous inks having excellent stability can be obtained. The dicyclopenta(ten)yl (meth)acrylate monomer includes dicyclopentanyl acrylate monomer, dicyclopentenyl acrylate, dicyclopentanyl methacrylate monomer, and dicyclopentenyl methacrylate. In the present embodiment, in addition to the cyclohexyl (meth)acrylate monomer, the other hydrophobic vinyl monomers, and the dicyclopenta(ten)yl (meth)acrylate monomer, a monomer having a reactive crosslinking group such as an epoxy group, a hydroxymethylamide group, or an isocyanate group, or a polyfunctional monomer having two or more vinyl groups may be appropriately blended to perform crosslinking during the emulsion polymerization.

[0042] In this embodiment, the content of the cyclohexyl (meth)acrylate monomer among all the polymer components constituting the colored resin microparticles must be 30 mass% or more, preferably 30 to 95 mass%, and more preferably 30 to 70 mass%, based on all the polymer components constituting the colored resin microparticles. In this embodiment, the term "total polymer components" refers to the polymerizable components constituting the colored resin microparticles, specifically, the total amount of the cyclohexyl (meth)acrylate monomer used, the other monomer components used, and the crosslinking agent described below. The effect of the present embodiment can be achieved by making the content of the cyclohexyl (meth)acrylate monomer 30% by mass or more based on the total polymer components. On the other hand, if the content is less than 30% by mass, the stability over time will be poor, which is not preferable.

[0043] Furthermore, among the polymer components constituting the colored resin microparticles for aqueous inks, the content of monomer components other than the cyclohexyl (meth)acrylate monomer is the remainder of the total amount of the cyclohexyl (meth)acrylate monomer and the crosslinking agent described below. The content of the other monomer components is preferably 5 to 65% by mass based on the total polymer components, from the viewpoints of further exerting the effects of the present embodiment, dispersibility, and reactivity.

[0044] In the present embodiment, the content of the basic dye or oil-soluble dye must be 15 parts by mass or more, preferably 15 to 50 parts by mass, and more preferably 15 to 40 parts by mass, based on 100 parts by mass of the total polymer components, from the standpoints of color development, obtaining sufficient line density, stability, and the like. By making the content of this dye equal to or greater than the above-mentioned 15 parts by mass, sufficient color development and sufficient line density can be achieved, whereas if the content of the dye is less than the above-mentioned 15 parts by mass, the color development becomes insufficient.

[0045] The polymerizable surfactant that can be used as necessary is not particularly limited as long as it is a polymerizable surfactant that is usually used in the emulsion polymerization, and for example, an anionic or nonionic polymerizable surfactant can be used. Examples of such surfactants include Adeka Reasoap NE-10, NE-20, NE-30, NE-40, and SE-10N (ADEKA), Latemul S-180, S-180A, and S-120A (Kao), Eleminol JS-20 (Sanyo Chemical Industries), and Aqualon KH-10 (Dai-ichi Kogyo Seiyaku). These polymerizable surfactants may be used alone or in combination of two or more kinds. The amount of these polymerizable surfactants used is 0 to 50 parts by mass, preferably 0.1 to 50 parts by mass, based on 100 parts by mass of the total polymer components. The content of the crosslinking agent is preferably 0 to 50% by mass, and more preferably 0.1 to 25% by mass, of the total polymer components.

[0046] In the present embodiment, the above-mentioned preferred embodiment, specifically, at least the above-mentioned basic dye or oil-soluble dye is dissolved in the above-mentioned cyclohexyl (meth)acrylate monomer and emulsion polymerization is performed, or at least a mixed monomer containing the above-mentioned cyclohexyl (meth)acrylate monomer and other monomer components is polymerized and then a basic dye or oil-soluble dye is dissolved and dyed, thereby obtaining a dispersion in which colored resin microparticles having a resin solid content of 20 to 50% by mass are dispersed in water. This dispersion of colored resin microparticles is a colorant that has superior color development and stability over time compared to conventional colorants, and is useful as an ink colorant suitable for writing instruments such as felt-tip pens, marking pens, and ballpoint pens.

[0047] In this embodiment, the average particle size of the colored resin microparticles in the dispersion liquid described above varies depending on the types and contents of the monomers used, including the cyclohexyl (meth)acrylate monomer, and the polymerization conditions, but is preferably 20 to 300 nm, more preferably 40 to 150 nm, and even more preferably 60 to 110 nm. By setting the average particle size within the above-mentioned preferred range, clogging does not occur in the first writing part 20, and further, excellent storage stability and the like are achieved. In addition, the "average particle size" defined in this embodiment is a histogram average particle size based on the scattered light intensity distribution, and is measured by a particle size distribution measuring device (FPAR1000, Otsuka Electronics). 50 can be a value of

[0048] The ink used in this embodiment is characterized by containing the colored resin particles having the above-mentioned composition, a water-soluble organic solvent, and water. Examples of the water-soluble organic solvent that can be used include ethylene glycol, triethylene glycol, tetraethylene glycol, propylene glycol, dipropylene glycol, 1,2-propanediol, 1,3-propanediol, 1,2-butanediol, 2,3-butanediol, 1,3-butanediol, 1,4-butanediol, 1,2-pentanediol, 1,5-pentanediol, 2,5-hexanediol, 3-methyl-1,3-butanediol, 2-methylpentane-2,4-diol, 3-methylpentane-1,3,5triol, 1,2,3-hexanediol, 2,4 ... Examples of the alkylene glycol include at least one of alkylene glycols such as Santriol, polyalkylene glycols such as polyethylene glycol and polypropylene glycol, glycerols such as glycerol, diglycerol and triglycerol, lower alkyl ethers of glycols such as ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether and diethylene glycol mono-n-butyl ether, N-methyl-2-pyrrolidone and 1,3-dimethyl-2-imidalidinone.

[0049] In addition, water-soluble solvents such as alcohols such as methyl alcohol, ethyl alcohol, isopropyl alcohol, n-butyl alcohol, tert-butyl alcohol, isobutyl alcohol, hexyl alcohol, octyl alcohol, nonyl alcohol, decyl alcohol, and benzyl alcohol, amides such as dimethylformamide and diethylacetamide, and ketones such as acetone can also be mixed. The content of these water-soluble organic solvents is preferably 1 to 40% by mass of the entire ink, and from the viewpoint of further improving the line drying properties, it is desirable to set the content to 10% by mass or less, more preferably 3 to 8% by mass.

[0050] The content of water (purified water, ion-exchanged water, distilled water, pure water, etc.) is preferably 30 to 90% by mass, and more preferably 40 to 60% by mass, based on the total mass of the ink. The content of the colored resin particles is preferably 1 to 30% by mass in terms of solid content with respect to the entire ink.

[0051] In the ink used in this embodiment, an appropriate preservative or antifungal agent, pH adjuster, defoamer, or the like may be appropriately selected and used as necessary within a range that does not impair the effect of the ink. For example, the pH adjuster may be at least one of ammonia, urea, monoethanolamine, diethanolamine, triethanolamine, aminomethylpropanol, sodium tripophosphate, alkali metal salts of carbonate or phosphoric acid such as sodium carbonate, and alkali metal hydroxides such as sodium hydroxide. In particular, it is preferable to use sodium hydroxide. As the preservative or antifungal agent, at least one of phenol, sodium omadine, sodium pentachlorophenol, 1,2-benzisothiazolin-3-one, 2,3,5,6-tetrachloro-4(methylphenoxy)pyridine, alkali metal salts of benzoic acid, sorbic acid, or dehydroacetic acid, benzimidazole compounds, and the like can be used. As the lubricant, at least one of phosphate esters, polyalkylene glycol derivatives such as polyoxyethylene lauryl ether, fatty acid alkali salts, nonionic surfactants, fluorine-based surfactants such as perfluoroalkyl phosphate esters, polyether-modified silicones such as polyethylene glycol adducts of dimethylpolysiloxane, and the like can be used.

[0052] The ink of this embodiment can be prepared by appropriately combining at least the dispersion of colored resin microparticles having the above-described configuration, a water-soluble solvent, and other components depending on the application of the ink for a writing instrument (for a ballpoint pen, a marking pen, etc.), stirring and mixing the mixture with a stirrer such as a homomixer, a homogenizer, or a disper, and further removing coarse particles in the ink composition by filtration or centrifugation, if necessary.

[0053] The writing instrument 1 of this embodiment stores the ink having the above composition in the ink storage section 15. With the writing instrument 1 configured in this manner, sufficient line density can be obtained, and the stored ink has excellent stability over time.

[0054] <Main components> Here, the first writing section 20 and the second writing section 30, which are essential parts of this embodiment, will be described in detail.

[0055] [First Writing Section] As shown in FIG. 2, the first writing part 20 has an outer circumferential part 21, a flow path 22, a tip part 23, a rear end part 24 (see FIG. 1B), and a body part 25. The first writing part 20 is an ink supply core formed by extrusion molding of polyacetal resin, and has a generally cylindrical shape from the front to the rear, with the tip part 23 being conical in shape with a diameter tapering toward the front and the rear part 24 being conical in shape with a diameter tapering toward the rear, and the body part 25 sandwiched between the tip part 23 and the rear part 24 being cylindrical in shape with an outer diameter the same as the outer diameter of the part where the diameter tapering begins of the tip part 23 and the rear part 24. Here, the first writing part 20 may be formed of a fiber bundle core, a sintered core, or the like.

[0056] (Outer periphery) The outer periphery 21 forms the outer surface of the first writing part 20. The tip of the front end 23 and the tip of the rear end 24 of the outer periphery 21 are formed so that a flow path 22, which will be described later, is exposed. (Flow path) The flow passage 22 is formed along the axis inside the outer circumferential portion 21, and is exposed at the front end 23 and the rear end 24 of the outer circumferential portion 21, as described above. Here, when extruding the first writing part 20, a die having a small gap in the center is used, so that the flow path 22 is formed as a small gap in the center of the cross section. The flow path 22 as a gap exerts a capillary force to hold the ink. In this case, the outer periphery 21 and the flow path 22 are integrally molded in the first writing part 20. In the cross-sectional view of FIG. 10A, flow path 22 is formed as a portion along the axis, that is, a portion occupying diameter W2, and the portion occupying the periphery thereof is outer circumferential portion 21. The flow path 22 is formed as a region having an irregular cavity at the inner periphery of the axial portion, for example, as shown in the cross-sectional view of the first writing part 20 in Fig. 10B, and the outer diameter W2 of the flow path is determined as the diameter of a circle virtually circumscribing the cavity. The flow path 22 may also be formed as a region having a cavity having finer branches than the flow path 22 shown in Fig. 10B, as shown in another example in the cross-sectional view of Fig. 10C. In this other example, the outer diameter W2 of the flow path is larger than that of the example shown in Fig. 10B, and the proportion of the flow path 22 in the cross section of the first writing part 20 is higher. In addition, when the flow path 22 is formed with a fiber bundle core or sintered core having a capillary structure, by forming the outer circumferential portion 21 as a structure that coats the outer surface of the flow path 22, it becomes possible for this outer circumferential portion 21 in the first writing part 20 to be a thick portion on the outside of the flow path 22, and the flow path 22 can be fixed to the second writing part 30 without exposing the outer surface thereof. In the first writing part 20, the ink stored in the ink storage part 15 is guided from the rear end part 24 inserted into the ink storage part 15 to the tip part 23 by capillary force.

[0057] [Second Writing Section] The second writing portion 30 is a lead surrounding member located around the first writing portion 20 and has, from the front side to the rear side, a tip portion 30A, a central portion 30B, and a rear end portion 30C, as shown in Figures 7A to 7C. The tip portion 30A has a reduced diameter portion 31, a cylindrical portion 32, and an engagement portion 33. The center portion 30B is composed of an elastic portion . The rear end portion 30C is composed of a tubular portion . Also, it has a through-hole 37 that passes through each of these parts from the front end to the rear end. The first writing part 20 passes through this through-hole 37 as shown in FIG. In this embodiment, the reduced diameter portion 31, the cylindrical portion 32, the engaging portion 33, the elastic portion 34, and the tubular portion 35 are integrally formed, and the basic shape other than the reduced diameter portion 31 is cylindrical. From the viewpoints of low friction during writing, wear resistance, and creep resistance of the elastic portion 34, the second writing portion 30 is preferably formed from a polyacetal resin.

[0058] (Reduced diameter part) As shown in FIG. 7C, reduced diameter portion 31 is located on the front side of second writing portion 30, and is formed in a tapered shape that reduces in diameter toward the front. A circular tip opening 31A is formed at the tip of reduced diameter portion 31, and an opening rim portion 31B is formed around the tip opening 31A. On the other hand, through portion 37 in reduced diameter portion 31 is a first through portion 37A.

[0059] This first penetrating portion 37A has a stop surface 37A1 that narrows in diameter toward the tip opening 31A, and the side of the tip portion 23 of the first writing portion 20 mentioned above contacts and engages with this stop surface 37A1, causing the tip of the tip portion 23 of the first writing portion 20 to protrude outward (see Figure 2). 7C, the first through-hole 37A in the reduced diameter portion 31 has an inner diameter that expands rearward from the tip opening 31A. This shape corresponds to the conical shape of the outer circumferential surface of the tip portion 23 of the first writing part 20.

[0060] (Cylindrical part) As shown in FIGS. 7A to 7C, cylindrical portion 32 is formed in a cylindrical shape that is continuous with the rear side of reduced diameter portion 31 and has the same outer diameter as the rear end of reduced diameter portion 31 and extends rearward. The through-hole 37 in the cylindrical portion 32 is continuous with the reduced diameter portion 31 to form a first through-hole 37A. The first through portion 37A in this cylindrical portion 32 is formed as a hole with a circular cross section having an inner diameter equal to the inner diameter of the rear end of the first through portion 37A in the reduced diameter portion 31, and is given an inner diameter larger than the outer diameter of the first writing portion 20 so that the first writing portion 20 can move in the axial direction.

[0061] (Engagement part) 7A to 7C, the engagement portion 33 is provided continuously from the rear end of the cylindrical portion 32 via a disk-shaped engagement piece 33A having an outer diameter larger than that of the cylindrical portion 32. The outer diameter of the engagement portion 33 is larger than that of the cylindrical portion 32 and smaller than that of the engagement piece 33A. The engagement portion 33 is formed in a substantially cylindrical shape with a notch in the axial direction on part of the side surface. As shown in FIG. 7C, inside this engaging portion 33, a first through portion 37A penetrating through the cylindrical portion 32 is formed as a circular hole having the same inner diameter and continuing to extend rearward.

[0062] (Elastic part) 7A to 7C, in this embodiment, the elastic portion 34 is formed as a double spiral spring that continues to the rear side of the engagement portion 33 and has an outer diameter substantially the same as the outer diameter of the rear end of the engagement portion 33. The cross section of this spiral spring is triangular as shown in FIG. 7C. 7C, a second through-hole 37B continuing from the rear end of the first through-hole 37A is formed inside the spiral spring 34. The second through-hole 37B has an inner diameter substantially the same as the inner diameter of the first through-hole 37A and is formed as a circular hole extending rearward. The helical spring is an example of the shape of the elastic portion .

[0063] The spiral spring serving as the elastic portion 34 is formed with a predetermined spring constant to accommodate a fine-point pen or marking pen, and is configured to impart a spring force to the first writing portion 20 sufficient to move it in the axial direction as described below.

[0064] (cylindrical part) As shown in FIGS. 7A to 7C, the tubular portion 35 is continuous with the rear end of the elastic portion 34, has an outer diameter substantially the same as the outer diameter of the elastic portion 34, and presents a cylindrical shape extending rearward. In the inside of this cylindrical portion 35 as well, a third through portion 37C having substantially the same inner diameter as the second through portion 37B in the elastic portion 34 is formed as a circular hole extending rearward, which is continuous with the second through portion 37B in the elastic portion 34. At the rear end of the cylindrical portion 35, a rear opening 35A is formed.

[0065] In this way, the second writing portion 30 is composed of multiple parts from the front to the rear, and the first writing portion 20 is inserted from the rear opening 35A on the rear side of the second writing portion 30 into the first through portion 37A, the second through portion 37B, and the third through portion 37C.

[0066] The shape of the spiral spring constituting the elastic portion 34 is not limited to this, and may be, for example, one having a rectangular cross section as shown in FIGS. 8A and 8B.

[0067] [Fixing the first writing part to the second writing part] Here, the fixing of the first writing part 20 and the second writing part 30 will be described. As described above, the first writing part 20 penetrates through the through parts 37 of the second writing part 30 (the first through part 37A, the second through part 37B, and the third through part 37C).

[0068] In this embodiment, as shown in Figures 9A and B, the first writing part 20 is fixed by compressing the punch fixing part 36 by impact deformation using a punch on the outer peripheral surface of the tubular part 35 that constitutes the rear end 30C of the second writing part 30, so that the protrusion 36A formed on the inner surface of the tubular part 35 presses against the outer peripheral surface of the first writing part 20. That is, the first writing part 20 and the second writing part 30 are fixed only at the rear end part 30C of the second writing part 30, and are not fixed at the tip part 30A and the central part 30B. As a result, inside the first through-hole 37A of the tip portion 30A and the second through-hole 37B of the central portion 30B, the first writing part 20 is not fixed and is movable. Furthermore, when a large load is applied to the first writing part 20 during writing, the first writing part 20 moves back and acts as a cushion, making it possible to prevent the first writing part 20 from breaking.

[0069] <Function of main parts> Based on the above-mentioned configuration, in the writing instrument 1, the first writing part 20 can be moved to the rear of the second writing part 30 by writing pressure, which will be described with reference to Figs. 2, 9A and 9B, and 10.

[0070] The writing instrument 1 in this embodiment has a first writing part 20 and a second writing part 30, and the first writing part 20 has a configuration in which the tip of the second writing part 30 moves backward due to writing pressure. The reason why the writing instrument 1 is capable of freely changing the width of the drawn line depending on the writing pressure is as follows.

[0071] First, when attempting to draw a thin line, a writing pressure of a predetermined level or less is applied to the writing instrument 1, and at this time, the tip 23 of the first writing part 20 is in a position protruding a predetermined length (for example, about 0.1 mm) from the tip opening 31A of the second writing part 30, as shown in Figures 9A and 10. With the tip 23 of the first writing part 20 in such a position, it is possible to draw a line on paper or the like (not shown). At this time, the elastic part 34, which is a spiral spring, maintains the length L1 as shown in FIG. 9A, and the first writing part 20 does not move backward.

[0072] Next, when a thicker line is to be drawn, a writing pressure greater than the predetermined pressure is applied to the writing instrument 1. Here, the first writing part 20 is fixed within the third through portion 37C of the tubular portion 35 of the second writing part 30 by the protrusion 36A of the tubular portion 35 (rear end portion 30C) of the second writing part 30, as shown in FIG. 9B.

[0073] On the other hand, the first writing part 20 is not fixed in the tip portion 30A of the second writing part 30, and in the first through portion 37A and the second through portion 37B in the central portion 30B, and when writing pressure is applied, the first writing part 20 tends to move backward. Then, the first writing part 20, which is fixed to the tubular part 35 of the second writing part 30, pushes the tubular part 35 backward against the biasing force of the elastic part 34, and as shown in Figure 9B, the elastic part 34, which has a length L1, extends by a length Lx to a length L2. The spiral spring constituting this elastic portion 34 is set to a spring constant that allows it to expand only in response to the writing pressure applied to the first writing portion 20 when attempting to write bold characters (which is greater than the writing pressure applied to the first writing portion when attempting to write thin characters).

[0074] As a result, the tip 23 of the first writing part 20 moves rearward to such an extent that its tip protrudes slightly from the tip opening 31A of the second writing part 30, creating a small gap between it and the opening peripheral part 31B that surrounds the periphery of the tip opening 31A. Ink is also supplied to the small gap between the tip 23 of the first writing part 20 and the opening periphery 31B surrounding the tip opening 31A. At the same time, the tip 23 of the first writing part 20 and the opening periphery 31B of the second writing part 30 come into contact with paper or the like (not shown), allowing thicker lines to be drawn.

[0075] In this manner, the writing instrument 1 in this embodiment is capable of changing the width of the drawn line to a thicker one even when the writing instrument 1 is a felt-tip pen or a marking pen equipped with the first writing part 20 for thin writing. Furthermore, even if excessive writing pressure is applied, the first writing part 20 is movable and a load is applied to the second writing part 30, so that poor writing due to buckling or crushing of the first writing part 20 can be prevented.

[0076] <Protrusion dimension of the tip of the first writing part> Next, the relationship between the tip of the first writing part and the protruding dimension from the tip opening of the second writing part will be described. A protruding dimension H1 (see FIG. 10) of the tip end 23 of the first writing part 20 from the tip opening 31A of the second writing part 30 is 0.05 to 0.7 mm when not writing. This protruding dimension is more preferably in the range of 0.1 to 0.3 mm, and most preferably 0.2 mm. If the protruding dimension is less than 0.05 mm, it becomes difficult to draw a line, and if the protruding dimension exceeds 0.7 mm, the distance between the first writing part 20 and the second writing part 30 becomes too large, which can cause blurring and makes the first writing part 20 more likely to break or buckle due to writing pressure.

[0077] <Overall configuration of the second embodiment> As shown in Fig. 11A, the writing instrument 1 according to the second embodiment comprises a barrel 10 in which a smaller diameter front barrel 11 and a larger diameter rear barrel 12 are integrally formed (see Fig. 12), and a second writing part 30 attached to the front side of the front barrel 11. As shown in Fig. 11C, an ink storage part 15 in which ink is stored is housed inside the rear barrel 12. An air replacement port 11E is provided near the tip of the front barrel 11, which allows air to flow between the inside and outside of the barrel 10. The first writing part 20 penetrates the second writing part 30. The tip of the first writing part 20 protrudes from the tip of the second writing part 30. The rear end of the first writing part 20 extends until it penetrates the front end of the ink storage part 15. Moreover, a cap 50 is attached to front barrel 11 shown in FIG. 11A, and when not in use, it presents the appearance shown in FIG. 11B.

[0078] (Structure of the barrel) 11C and 14A-E (or 15A-E), barrel tube 10 has front barrel 11 and rear barrel 12, as described above. A front opening 13 opens at the front end of front barrel 11, and a rear opening 14 opens at the rear end of rear barrel 12. A tail plug 60 is press-fitted into rear opening 14. As shown in FIG. 14A (or FIG. 15A), the outer shape of the barrel 10 is formed such that the cross section in the transverse direction is a generally rounded rectangle.

[0079] As shown in FIG. 12 and FIGS. 14A, B, and E (or FIGS. 15A, B, and E), the rear axle 12 is integrally formed with a front grip portion 12A on the front side covered with a grip member 40 described later, and a rear grip portion 12B on the rear side. Furthermore, at a boundary 12C between front grip portion 12A and rear grip portion 12B, there is a step that narrows in diameter toward the front, so that front grip portion 12A is thinner than rear grip portion 12B. 14A and 14B, outer projections 12A2 are formed on each outer circumferential surface of the front gripping portion 12A, which are involved in engagement with the gripping member 40. The outer projections 12A2 fit into inner recesses 41 (see FIGS. 13C and 13F) formed on the inner circumferential surface of the gripping member 40, which will be described later. Further, front end 12E of front grip portion 12A is formed with a surface whose transverse cross section is shaped like a convex arc, and front barrel 11 formed integrally in front of it is thinner than this end 12E. Furthermore, a flange 62 of a tail plug 60 is in contact with the rear end edge of the rear body 12 (see FIG. 11C).

[0080] As shown in FIG. 12 and FIGS. 14A, B, and E (or FIGS. 15A, B, and E), front barrel 11 has, from the rear end, base portion 11A, reduced diameter portion 11B, tip portion 11C, and locking surface 11D. The base portion 11A is a portion that extends forward with a certain thickness from the front end portion 12E of the front grip portion 12A. As shown in Figs. 14A and 14B, a protrusion is formed on each side of the middle portion of the base portion 11A along a direction intersecting with the axial direction. These protrusions are called locking protrusions 11A1. In this embodiment, a total of four locking protrusions 11A1 (Figs. 14A and 14B) or a total of two locking protrusions 11A1 (Figs. 15A or 15B) are provided, which makes it possible to suppress variations in the fitting force caused by variations in the processing of the height of the locking protrusions 11A1, so that even a user with weak hand strength can easily attach and remove the cap 50. The locking protrusions 11A1 may be formed not only on the front barrel 11 side but also on the cap 50 side. The locking projection 11A1 has a tip end surface and a rear end surface that are both inclined, with the tip end surface having a larger angle, which makes it possible to securely attach the cap 50 while reducing the force required to remove the cap 50, thereby providing a good fit when attaching and removing the cap 50. The reduced diameter portion 11B is a portion that tapers and extends forward from the front end of the base portion 11A. The tip portion 11C is a portion that extends forward with a constant thickness from the front end of the reduced diameter portion 11B. The locking surface 11D is the tip edge of the tip portion 11C, and is in contact with the engagement piece 33A of the engagement portion 33 of the second writing part 30.

[0081] (Grip member) As shown in FIGS. 13A to 13F, the gripping member 40 is formed in a cylindrical shape having a substantially square cross section as a whole, and has a front opening 42 that opens to the front and a rear opening 43 that opens to the rear. The inner recesses 41 are formed as inwardly facing recesses on each inner surface near the rear end of the grip member 40. The grip member 40 is attached to the rear axle 12 by fitting outer projections 12A2 provided on the outer periphery of the front grip portion 12A of the rear axle 12 into these inner recesses 41. Edge portion 42A is formed at the end of front opening 42. The inner surface of edge portion 42A is formed with a concave arc shape in cross section to correspond to the convex arc shape of the cross section of end 12E of front grip portion 12A. Front opening 42 is formed with a size that allows root portion 11A of front barrel 11 to fit therein. An end face 43A is formed at the end of the rear opening 43, and is in contact with a stepped surface of a boundary portion 12C of a rear grip portion 12B of the rear body 12. Furthermore, the grip member 40 may be given a color different from that of the barrel 10, and the color may be similar to the color of the ink stored in the ink storage section 15, for example. The barrel 10 and the gripping member 40 can be formed by two-color molding, for example.

[0082] (cap) The structure of the cap 50 is almost the same as that of the first embodiment (see FIGS. 4A to 4C and 5A and B).

[0083] (tail plug) 16A and 16B, the tail plug 60 is formed into a cylindrical shape as a whole, and has an insertion portion 61, a flange portion 62, and a head portion 63. The tip of the insertion portion 61 forms a tail portion 64. The insertion portion 61 is inserted into the interior of the rear body 12 from the rear opening 14 of the rear body 12 in the barrel 10, and closes the rear opening 14 (see FIG. 11C). The flange portion 62 fits tightly against the end face of the rear opening 14 to seal the inside of the rear body 12 and isolate the inside of the rear body 12 from the outside air. The head portion 63 is formed so as to extend rearward from the flange portion 62, and the cap 50 can be attached thereto when writing.

[0084] The shape of the tail plug 60 is such that the cross section of the insertion portion 61, the flange portion 62, and the head portion 63 are all circular. In addition, the outer periphery from the head portion 63 to the flange portion 62 is connected by a gently concave curved surface. This makes the boundary between the head portion 63 and the flange portion 62 inconspicuous, and does not mar the appearance.

[0085] (ink storage section) Ink storage section 15 shown in FIG. 11C is a cylindrical batting made of polyester fiber material that stores ink, and is housed inside rear barrel 12 of barrel tube 10. As shown in FIG. 12, the front end of the ink storage section 15 contacts a plurality of ribs 12A1 (see FIGS. 14C and E (or FIGS. 15C and E)) formed in the axial direction on the inner surface of the front grip portion 12A inside the front grip portion 12A of the rear barrel 12. On the other hand, the rear end of the ink reservoir 15 is located immediately before the tail portion 64 of the tail plug 60 which fits onto the rear barrel 12 . 1B, the ink reservoir 15 is located between the rib 12A1 (see FIG. 14E (or FIG. 15E)) of the front grip portion 12A and the tail portion 64 of the tail plug 60. A plurality of fixing protrusions 12B1 (see FIG. 14E (or FIG. 15E)) are arranged in an annular shape on the inner surface of the rear grip portion 12B, which fix the ink reservoir 15 inside the rear barrel 12.

[0086] (ink) The ink is the same as in the first embodiment.

[0087] <Main components> Here, the first writing section 20 and the second writing section 30, which are essential parts of this embodiment, will be described in detail.

[0088] [First Writing Section] As shown in FIG. 12, the first writing part 20 has an outer circumferential part 21, a flow path 22, a tip part 23, a rear end part 24, and a body part 25. The first writing part 20 is an ink supply core formed by extrusion molding of polyacetal resin, and has a generally cylindrical shape from the front to the rear, with the tip part 23 being conical in shape with a diameter tapering toward the front and the rear part 24 being conical in shape with a diameter tapering toward the rear, and the body part 25 sandwiched between the tip part 23 and the rear part 24 being cylindrical in shape with an outer diameter the same as the outer diameter of the part where the diameter tapering begins of the tip part 23 and the rear part 24. Here, the first writing part 20 may be formed of a fiber bundle core, a sintered core, or the like.

[0089] (Outer periphery) The outer periphery 21 forms the outer surface of the first writing part 20. The tip of the front end 23 and the tip of the rear end 24 of the outer periphery 21 are formed so that a flow path 22, which will be described later, is exposed. (Flow path) The flow passage 22 is formed along the axis inside the outer circumferential portion 21, and is exposed at the front end 23 and the rear end 24 of the outer circumferential portion 21, as described above. Here, when extruding the first writing part 20, a die having a small gap in the center is used, so that the flow path 22 is formed as a small gap in the center of the cross section. The flow path 22 as a gap exerts a capillary force to hold the ink. In this case, the outer periphery 21 and the flow path 22 are integrally molded in the first writing part 20. The flow path 22 is similar to that in the first embodiment (see FIGS. 10A to 10C). In addition, when the flow path 22 is formed with a fiber bundle core or sintered core having a capillary structure, by forming the outer circumferential portion 21 as a structure that coats the outer surface of the flow path 22, it becomes possible for this outer circumferential portion 21 in the first writing part 20 to be a thick portion on the outside of the flow path 22, and the flow path 22 can be fixed to the second writing part 30 without exposing the outer surface thereof. In the first writing part 20, the ink stored in the ink storage part 15 is guided from the rear end part 24 inserted into the ink storage part 15 to the tip part 23 by capillary force.

[0090] [Second Writing Section] The second writing part 30 is similar to that of the first embodiment (see FIGS. 7A to 7C and FIGS. 8A and 8B).

[0091] <Function of main parts> The operation of the main parts is similar to that of the first embodiment.

[0092] In this embodiment, as shown in Fig. 17A, a step 26 that discontinuously reduces the outer diameter is provided around the entire circumference at the tip of the first writing part 20. This provides an expansion part 70 in which the gap between the first writing part 20 and the second writing part 30 expands around the entire circumference. The distance between the first writing part 20 and the second writing part 30 in the expansion part 70 is set to a length that does not cause capillary force with respect to the ink used in the writing instrument 1.

[0093] In the first writing part 20, the ink guided by the flow path 22 seeps out from the tip part 23 that is not covered by the outer circumferential part 21, and would normally be transferred to the writing surface to form a drawn line. However, some of the seeped ink permeates the gap between the outer circumferential surface of the tip part 23 of the first writing part 20 and the inner circumferential surface of the reduced diameter part 31 of the second writing part 30 due to capillary force, and rises backward. However, when the rising ink reaches the expansion part 70, it loses its capillary force and does not rise any further backward. This prevents the ink from rising up to the inside of the barrel 10.

[0094] 17B, ​​by providing an annular groove 27 around the entire circumference at a position near the tip of the body 25 of the first writing part 20, the gap between the first writing part 20 and the second writing part 30 at the position of this annular groove 27 can be made into an expansion part 70. In this modification, the expansion part 70 also prevents the ink from rising up.

[0095] <Other> Although specific embodiments of the present invention have been described in detail above, it will be apparent to those skilled in the art that the present invention is not limited to such embodiments, and that various other embodiments are possible within the scope of the present invention.

[0096] For example, although the embodiment has been described in which the tip portion 30A and the central portion 30B of the second writing part 30 are integrally formed, the central portion 30B may be configured as a separate body. For example, the tip portion 30A and the rear end portion 30C may be formed of the same resin material as in the embodiment, and a metal spring may be interposed between them as the central portion 30B.

[0097] Further, the means for storing ink has been described as the ink storage section 15, but it may be in the form of an ink tank.

[0098] <Case of the first embodiment> [exterior] The writing instrument 1 of the first or second embodiment described above can be stored in the case 100 of the first embodiment described below.

[0099] Case 100 has an appearance as shown in the front top perspective view of Fig. 18A, the rear top perspective view of Fig. 18B, the front bottom perspective view of Fig. 18C, and the plan bottom perspective view of Fig. 18D. In Fig. 18A and Fig. 18B, the side seen as flat surface 155 on the near side is a flat surface, and the bottom surface is not seen on the far side. In Fig. 18C and Fig. 18D, the side seen as a curved surface on the near side is the bottom surface, and the flat surface is not seen on the far side.

[0100] The case 100 is made of a relatively soft synthetic resin (for example, polypropylene resin with a tensile modulus of elasticity of 200 to 1000 MPa conforming to JIS K7161), and as shown in Figs. 18A, 18B, 18C, and 18D, is composed of a flat box-shaped storage section 110 and a movable section 150 connected to the storage section 110 by a hinge section 121. Reinforcing ridges 125, 125 are respectively provided on the movable section 150 side and the storage section 110 side, sandwiching the hinge section 121, along the hinge section 121 (Figs. 18B, 18D). The storage section 110 is configured by combining a tray section 111 that forms the back side and a lid section 112 that covers the front side of the tray section 111 (Figs. 18A, 18C). The flat side of the storage section 110 is an open rectangular opening 120 (Fig. 18A). The writing instrument 1 can be inserted into and removed from the storage section 110 through this opening 120. The front side of the movable part 150 forms an open window 160 (FIGS. 18A and 18C). Note that in FIGS. 18A, 18B, 18C, and 18D, the movable part 150 is in a closed position relative to the opening 120 of the storage section 110.

[0101] 19A, 19B, 19C, 19D, 19E, and 19F respectively show a front view, a back view, a plan view, a bottom view, a left side view, and a right side view of case 100. In the following description, the direction toward the planar side of case 100 may be referred to as the "front end direction" or the "front end side," and the direction toward the bottom side may be referred to as the "rear end direction" or the "rear end side."

[0102] 19A shows a front view of case 100. Movable section 150 located on the upper side and storage section 110 located on the lower side are connected by hinge section 121. Storage section 110 is configured by combining tray section 111 that forms the back side and lid section 112 that covers the front side of tray section 111. The front side of movable section 150 forms an open window section 160.

[0103] 19B is a rear view of case 100. Movable section 150 located on the upper side and storage section 110 located on the lower side are connected by hinge section 121. Storage section 110 is configured by combining tray section 111 forming the rear side and lid section 112 covering the front side of this tray section 111, but lid section 112 is not visible in this figure. Reinforcing ridges 125, 125 are provided on either side of hinge section 121, protruding along hinge section 121 on the movable section 150 side and the storage section 110 side, respectively.

[0104] Fig. 19C shows case 100 in a plan view. In this figure, flat surface 155 of movable section 150 is visible. Fig. 19D shows case 100 in a bottom view. In this figure, both side surfaces of tray section 111 constituting storage section 110 and curved surface 115 which is the bottom surface side of lid section 112 are visible. Also visible is reinforcing ridge 125 provided on the side of storage section 110.

[0105] 19E and 19F are left and right side views, respectively, of case 100. In both of these views, the side of movable part 150 located on the upper side and the side of tray part 111 constituting storage part 110 located on the lower side can be seen. Also, the shapes of flat surface 155 of movable part 150 and curved surface 115 of storage part 110 can be seen.

[0106] Opening FIG. 20 is a front top perspective view showing a state in which the movable part 150 is in an open position relative to the opening 120 of the storage part 110. The long side of the opening 120 on the rear side is a hinge part 121 interposed between the movable part 150 and the opening 120. The movable part 150 is connected to the storage part 110 via the hinge part 121. The hinge part 121 is formed to be thinner than the rear surface of the movable part 150 and the rear surface of the tray part 111. This allows the movable part 150 to rotate toward the rear side by elastically bending the hinge part 121. That is, the movable part 150 is rotatable relative to the opening 120 between a closed position shown in FIG. 18A and an open position shown in this figure.

[0107] The long side of the front side of the opening 120 is the leading edge 116 of the cover part 112. Both short sides of the opening 120 are opening edges 122, 122 that abut against the movable part in the closed position. Furthermore, support pieces 130, 130 protruding from the inner surface side of the opening edge 122 toward the leading edge are also visible. In other words, the support pieces 130, 130 protrude from the inner surface side of the opening edge toward the movable part 150. These support pieces 130, 130 are respectively extensions of both side surfaces of the tray part 111 toward the leading edge. Moreover, the rear edges of both side surfaces of the movable part 150 are abutting edges 151, 151 that abut against the opening edges 122, 122 described above in the closed position.

[0108] [Case molding] Case 100 is first molded as case molded product 101 in an unfolded state as shown in the front bottom perspective view of Figure 21. That is, in this case molded product 101, movable part 150 and tray part 111 are connected via hinge part 121, and tray part 111 and lid part 112 are connected via thinner connecting part 117.

[0109] Two side holes 111B are formed on each of tray side surfaces 111A, 111A, which are both side surfaces of tray portion 111. A plurality of recesses 113 are formed along the longitudinal direction of tray portion 111. These recesses 113 are shaped to accommodate the writing instrument 1 described above. In addition, some of the boundaries between the recesses 113 form partitions 114 that are thicker than the others. These partitions 114 can prevent the writing instrument 1 from rolling around inside case 100 when case 100 is tilted.

[0110] Two side projections 112B are formed on each of the cover side surfaces 112A, which are both side surfaces of the cover portion 112. When the cover portion 112 is bent toward the tray portion 111 at the connecting portion 117 and the cover side surface 112A is fitted inside the tray side surface 111A, each side projection 112B fits into the side hole 111B at the corresponding position. As a result, the cover portion 112 and the tray portion 111 are fixed to each other to form the storage portion 110. The end of each cover side surface 112A protrudes beyond the tip edge 116 as the support piece 130 described above. An engagement hole 131 is formed in the support piece 130. In this case molded product 101, the front side edge of the support piece 130 (this part becomes the rear side edge in the case 100 in the state shown in FIG. 18C) becomes the locking edge 132.

[0111] [Lid] Fig. 22 shows only the lid part 112 in a front top perspective view. That is, this figure shows only the lid part 112 in the state shown in Fig. 18A, and in reality, the lid part 112 is connected to the tray part 111 at the connecting part 117 on the rear end side, and the lid part 112 itself as shown in this figure does not actually exist as an independent part.

[0112] The rear end side of the lid portion 112 is formed as the curved surface 115 as described above. Each lid side surface 112A is provided with two side holes 111B as described above. An end of each lid side surface 112A protrudes beyond the tip edge 116 as a support piece 130. The support piece 130 is provided with the engagement hole 131 as described above. The flat side edge of the support piece 130 forms the locking edge 132 as described above. The support piece 130 has an engagement protrusion 133 protruding from the outer surface along the locking edge 132.

[0113] [Movable part] Fig. 23 is a front bottom perspective view of only the movable part 150. That is, this figure shows only the movable part 150 in the state shown in Fig. 18C, and in reality, the movable part 150 is connected to the tray part 111 at the hinge part 121 on the rear end side, and the movable part 150 itself does not actually exist as an independent part as shown in this figure.

[0114] As described above, the tip side of the movable part 150 is formed as a flat surface 155. The rear end edge of each side surface of the movable part 150 forms an abutment edge 151. On each side surface of the movable part 150, an engagement groove 153 is formed in the vicinity slightly closer to the tip than the abutment edge 151. In addition, an engagement protrusion 152 is provided protruding from the vicinity slightly closer to the tip than this engagement groove 153.

[0115] [Closed position] 18A to 18D, each of the abutment edges 151 of the movable part 150 abuts each of the opening edges 122 (see FIG. 20) of the opening 120. In this state, the engagement protrusion 152 of the movable part 150 fits into the engagement hole 131 (see FIG. 22) of the support piece 130. The engagement of the engagement protrusion 152 into the engagement hole 131 maintains the storage part 110 and the movable part 150 in the closed position.

[0116] [Open position] When the movable part 150 is bent backward from this closed position, the support pieces 130 are elastically deformed inward and the movable part 150 is elastically deformed outward, and the engagement between the engagement holes 131 and the engagement protrusions 152 is released. When the hinge part 121 is continued to be bent backward, the movable part 150 reaches the open position in which it stands up against the storage part 110 as shown in FIG.

[0117] FIG. 25 is an enlarged view of the surroundings of the support piece 130 in this open position. As shown in this figure, the locking edge 132 of the support piece 130 abuts against the engaging protrusion 152 of the movable part 150. In addition, the engaging protrusion 133 of the support piece 130 fits into the engaging groove 153 of the movable part. That is, the contact between the locking edge 132 and the engaging protrusion 152 and the fitting of the engaging protrusion 133 into the engaging groove 153 prevent the movable part 150 from rotating any further. At the same time, the two reinforcing protrusions 125, 125 are in contact with each other on the rear side of the case 100, and this contact also prevents the movable part 150 from rotating any further. The above-mentioned prevention of rotation of the movable part 150 maintains the open position of the storage part 110 and the movable part 150 as shown in FIG. 24.

[0118] When the movable part 150 is bent from this open position toward the front, the support pieces 130 are elastically deformed inward and the movable part 150 is elastically deformed outward, and the engaging protrusions 133 are released from the engaging grooves into which they were fitted. At the same time, the locking edges 132 are also separated from the engaging protrusions 152. When the hinge part 121 is continued to be bent toward the front, each of the abutment edges 151 of the movable part 150 comes into contact with each of the opening edges 122 of the opening 120. At the same time, the engaging protrusions 152 are fitted into the engaging holes 131, and the storage part 110 and the movable part 150 reach the closed position shown in Figures 18A to 18D again.

[0119] <Writing implement set> As described above, when the writing instrument 1 is stored in the case 100 consisting of the storage section 110 and the movable section 150, a writing instrument set 200 as shown in Fig. 26 is obtained. Note that, although the writing instrument set 200 shown in this figure stores one writing instrument 1, the writing instrument set 200 can store a plurality of writing instruments 1 in the case 100, up to the number of the recesses 113 (see Fig. 21) described above.

[0120] <Case of the second embodiment> [exterior] The writing instrument 1 of the first or second embodiment described above can also be stored in the case 100 of the second embodiment described below.

[0121] Case 100 has an appearance as shown in the front upper perspective view of Fig. 27A, the rear upper perspective view of Fig. 27B, the front lower perspective view of Fig. 27C, and the plan lower perspective view of Fig. 27D. In Fig. 27A and Fig. 27B, the side seen as flat surface 155 on the near side is a flat surface, and the bottom surface is not seen on the far side. In Fig. 27C and Fig. 27D, the side seen as a curved surface on the near side is the bottom surface, and the flat surface is not seen on the far side.

[0122] The case 100 is made of a relatively soft synthetic resin (for example, polypropylene resin with a tensile modulus of elasticity of 200 to 1000 MPa conforming to JIS K7161), and is composed of a flat box-shaped storage section 110 and a movable section 150 connected to the storage section 110 by a hinge section 121, as shown in Figs. 27A, 27B, 27C, and 27D. Reinforcing ridges 125, 125 are respectively provided on the movable section 150 side and the storage section 110 side, sandwiching the hinge section 121, along the hinge section 121 (Figs. 27B, 27D). The storage section 110 is configured by combining a tray section 111 that constitutes the back side and a lid section 112 that covers the front side of the tray section 111 (Figs. 27A, 27C). The flat side of the storage section 110 is an open rectangular opening 120 (Fig. 27A). The writing instrument 1 can be inserted into and removed from the storage section 110 through this opening 120. The front side of the movable part 150 forms an open window 160 (FIGS. 27A and 27C). Note that in FIGS. 27A, 27B, 27C, and 27D, the movable part 150 is in a closed position relative to the opening 120 of the storage section 110.

[0123] 28A, 28B, 28C, 28D, 28E, and 28F respectively show a front view, a back view, a plan view, a bottom view, a left side view, and a right side view of case 100. In the following description, the direction of the planar side of case 100 may be referred to as the "front end direction" or "front end side," and the direction of the bottom side may be referred to as the "rear end direction" or "rear end side."

[0124] 28A shows a front view of case 100. Movable section 150 located on the upper side and storage section 110 located on the lower side are connected by hinge section 121. Storage section 110 is configured by combining tray section 111 that forms the back side and lid section 112 that covers the front side of tray section 111. The front side of movable section 150 forms an open window section 160.

[0125] 28B is a rear view of case 100. Movable section 150 located on the upper side and storage section 110 located on the lower side are connected by hinge section 121. Storage section 110 is configured by combining tray section 111 forming the rear side and lid section 112 covering the front side of this tray section 111, but lid section 112 is not visible in this figure. Reinforcing ridges 125, 125 are provided on either side of hinge section 121, protruding along hinge section 121 on the movable section 150 side and the storage section 110 side, respectively.

[0126] Fig. 28C shows case 100 in a plan view. In this figure, flat surface 155 of movable section 150 is visible. Fig. 28D shows case 100 in a bottom view. In this figure, both side surfaces of tray section 111 constituting storage section 110 and curved surface 115 which is the bottom surface side of lid section 112 are visible. Also visible is reinforcing ridge 125 provided on the side of storage section 110.

[0127] 28E and 28F are left and right side views, respectively, of case 100. In both of these views, the side of movable part 150 located on the upper side and the side of tray part 111 constituting storage part 110 located on the lower side can be seen. Also, the shapes of flat surface 155 of movable part 150 and curved surface 115 of storage part 110 can be seen.

[0128] Opening FIG. 29 is a front top perspective view showing the movable part 150 in an open position relative to the opening 120 of the storage part 110. The long side of the opening 120 on the rear side is a hinge part 121 interposed between the movable part 150 and the opening 120. The movable part 150 is connected to the storage part 110 via the hinge part 121. The hinge part 121 is formed to be thinner than the rear surface of the movable part 150 and the rear surface of the tray part 111. This allows the movable part 150 to rotate toward the rear side by elastically bending the hinge part 121. That is, the movable part 150 is rotatable relative to the opening 120 between the closed position shown in FIG. 27A and the open position shown in this figure.

[0129] The long side of the front side of the opening 120 is the leading edge 116 of the cover part 112. Both short sides of the opening 120 are opening edges 122, 122 that abut against the movable part in the closed position. Furthermore, support pieces 130, 130 protruding from the inner surface side of the opening edge 122 toward the leading edge are also visible. In other words, the support pieces 130, 130 protrude from the inner surface side of the opening edge toward the movable part 150. These support pieces 130, 130 are respectively extensions of both side surfaces of the tray part 111 toward the leading edge. Moreover, the rear edges of both side surfaces of the movable part 150 are abutting edges 151, 151 that abut against the opening edges 122, 122 described above in the closed position.

[0130] [Case molding] Case 100 is first molded as case molded product 101 in an unfolded state as shown in the front bottom perspective view of Figure 30. That is, in this case molded product 101, movable part 150 and tray part 111 are connected via hinge part 121, and tray part 111 and lid part 112 are connected via thinner connecting part 117.

[0131] Two side holes 111B are formed on each of tray side surfaces 111A, 111A, which are both side surfaces of tray portion 111. A plurality of recesses 113 are formed along the longitudinal direction of tray portion 111. These recesses 113 are shaped to accommodate the writing instrument 1 described above. In addition, some of the boundaries between the recesses 113 form partitions 114 that are thicker than the others. These partitions 114 can prevent the writing instrument 1 from rolling around inside case 100 when case 100 is tilted.

[0132] Two side projections 112B are formed on each of the cover side surfaces 112A, which are both side surfaces of the cover portion 112. When the cover portion 112 is bent toward the tray portion 111 at the connecting portion 117 and the cover side surface 112A is fitted inside the tray side surface 111A, each side projection 112B fits into the side hole 111B at the corresponding position. As a result, the cover portion 112 and the tray portion 111 are fixed to each other to form the storage portion 110. The end of each cover side surface 112A protrudes beyond the tip edge 116 as the support piece 130 described above. A fitting projection 131A is protruded from the outer surface of the support piece 130. In this case molded product 101, the front side edge of the support piece 130 (this part becomes the rear side edge in the case 100 in the state shown in FIG. 27C) becomes the locking edge 132. In the support piece 130, the inner surface in the vicinity of the locking edge 132 is formed as a thin portion 130A whose thickness has been reduced.

[0133] [Lid] Figure 31 shows only the lid part 112 in a front top perspective view. That is, this figure shows only the lid part 112 in the state shown in Figure 27A, and in reality, the lid part 112 is connected to the tray part 111 at the connecting part 117 on the rear end side, and an independent lid part 112 as shown in this figure does not actually exist.

[0134] The rear end side of the lid portion 112 is formed as the curved surface 115 as described above. Each lid side surface 112A is provided with two side holes 111B as described above. The end of each lid side surface 112A protrudes beyond the tip edge 116 as the support piece 130. The fitting projection 131A described above protrudes from the outer surface of the support piece 130. The flat side edge of the support piece 130 forms the locking edge 132 described above. In the support piece 130, an engagement protrusion 133 protrudes from the outer surface along the locking edge 132. In addition, in the support piece 130, the inner surface near the locking edge 132 forms the thin-walled portion 130A whose thickness has been reduced as described above.

[0135] [Movable part] Fig. 32 is a front bottom perspective view of only the movable part 150. That is, this figure shows only the movable part 150 in the state shown in Fig. 27C, and in reality, the movable part 150 is connected to the tray part 111 at the hinge part 121 on the rear end side, and the movable part 150 itself does not actually exist as an independent part as shown in this figure.

[0136] As described above, the tip side of the movable part 150 is formed as a flat surface 155. The rear end edge of each side surface of the movable part 150 forms an abutment edge 151. On each side surface of the movable part 150, an engagement hole 153A is formed at a position closer to the front and slightly closer to the tip than the abutment edge 151. In addition, an engagement protrusion 152 is provided protrudingly in the vicinity of and slightly closer to the tip than this engagement hole 153A.

[0137] [Closed position] 27A to 27D, each of the abutment edges 151 of the movable part 150 abuts each of the opening edges 122 (see FIG. 29) of the opening 120. In this state, the engagement hole 153A of the movable part 150 fits into the engagement protrusion 131A (see FIG. 31) of the support piece 130. The engagement of the engagement protrusion 131A with the engagement hole 153A maintains the storage part 110 and the movable part 150 in the closed position.

[0138] [Open position] When the movable part 150 is bent backward from this closed position, the support pieces 130 are elastically deformed inward and the movable part 150 is elastically deformed outward, and the fitting protrusions 131A and the engagement holes 153A are released. When the hinge part 121 is continued to be bent backward, the movable part 150 reaches the open position in which it stands up against the storage part 110 as shown in FIG.

[0139] FIG. 34 is an enlarged view of the surroundings of the support piece 130 in this open position. As shown in this figure, the locking edge 132 of the support piece 130 abuts against the engaging protrusion 152 of the movable part 150. That is, the contact between the locking edge 132 and the engaging protrusion 152 prevents the movable part 150 from rotating any further. At the same time, on the rear side of the case 100, the two reinforcing protrusions 125, 125 are in contact, and this contact also prevents the movable part 150 from rotating any further. By preventing the movable part 150 from rotating as described above, the storage part 110 and the movable part 150 are maintained in the open position as shown in FIG.

[0140] When movable part 150 is bent from this open position toward the front, support pieces 130 elastically deform inward and movable part 150 elastically deforms outward, and locking edges 132 move away from engagement protrusions 152. When hinge part 121 is bent in this state toward the front, each of abutment edges 151 of movable part 150 abuts against each of opening edges 122 of opening 120. At the same time, engagement protrusions 131A engage with engagement holes 153A, so that storage part 110 and movable part 150 reach the closed position shown in Figures 27A to 27D again.

[0141] <Writing implement set> As described above, the case 100 of the second embodiment houses a knock-type writing instrument 1 that can be extended and retracted by pressing the operation part at the rear end of the writing instrument 1 housed in the barrel as a writing core, resulting in a writing instrument set as shown in FIG. 35. The rest is the same as the writing instrument set of the first embodiment. In addition, in the case of the knock-type writing instrument 1, the drying resistance of the pen tip can be improved by using trimethylglycine as a moisturizing agent in the writing ink. In addition, it is desirable that the content of trimethylglycine is 0.5 to 50%, preferably 1 to 15%, and more preferably 2 to 10% with respect to the total amount of the ink composition. If the content is less than 0.5%, the effect of suppressing drying of the pen tip is insufficient, while if it exceeds 50%, the effect is not so different, and rather, the writing performance and storage stability are deteriorated due to the increase in viscosity. EXAMPLES

[0142] <Production Examples 1 to 12: Production of Dispersion of Colored Resin Particles> According to the following Production Examples 1 to 12, dispersions of each colored resin particle were produced.

[0143] (Production Example 1) A 2-L flask was fitted with a stirrer, a reflux condenser, a thermometer, a nitrogen gas inlet tube, and a 1000 ml separating funnel for introducing monomers, and set in a warm water bath. 329.5 parts by mass of distilled water, 5 parts by mass of glycerin monomethacrylate (Blenmer GLM, NOF Corp.), 5 parts by mass of sodium 2-sulfoethyl methacrylate (acrylic ester SEM-Na, Mitsubishi Chemical), 20 parts by mass of a polymerizable surfactant (ether sulfate, trade name ADEKA REASOAP SE-10N, ADEKA), and 0.5 parts by mass of ammonium persulfate were charged into the flask, and the internal temperature was raised to 50° C. while introducing nitrogen gas.

[0144] Meanwhile, a liquid was prepared by mixing a monomer mixture consisting of 55 parts by mass of cyclohexyl methacrylate monomer and 35 parts by mass of n-butyl methacrylate as another monomer with 40 parts by mass of an oil-soluble dye (Suninyl Blue GLS, Clariant) and 10 parts by mass of a crosslinking agent (triallyl isocyanurate, trade name TAIC, Nippon Kasei). This preparation liquid was added from the separating funnel to the flask kept at about 50°C over a period of 3 hours while stirring, and emulsion polymerization was carried out. The mixture was further aged for 5 hours to terminate the polymerization, and a dispersion of colored resin particles (particles 1) was obtained. The total amount of the dispersion was 500 parts by mass. From the above, the total polymer component is 110 parts by mass, which is the sum of glycerin monomethacrylate (5 parts by mass), 2-sulfoethyl sodium methacrylate (5 parts by mass), cyclohexyl methacrylate monomer (55 parts by mass), n-butyl methacrylate (35 parts by mass), and crosslinker (10 parts by mass). The content of the cyclohexyl methacrylate monomer (55 parts by mass) was 50.0% by mass relative to the total polymer components (110 parts by mass) constituting the particles 1, which exceeded 30% by mass. In addition, the amount of the oil-soluble dye was 40 parts by mass, and the total polymer components were 110 parts by mass. When the total polymer components were converted to 100 parts by mass, the relative amount of the oil-soluble dye as a dye component was 36.4 parts by mass, which was more than 15 parts by mass. The ratio of the resin solid content (150 parts by mass) represented by the sum of all polymer components (110 parts by mass) and oil-soluble dye (40 parts by mass) to the total amount of the dispersion (500 parts by mass) was 30.0% by mass. The average particle size of Particle 1 was 40 nm.

[0145] (Production Example 2) A dispersion of colored resin fine particles (particles 2) was obtained in the same manner as in Production Example 1, except that in Production Example 1, the amount of distilled water was 340.5 parts, the amount of cyclohexyl methacrylate monomer was 30 parts, the amount of n-butyl methacrylate was 45 parts, and the dyes used were 20 parts of an oil-soluble dye (Valifast Pink 2310N, Orient Chemical Industry Co., Ltd.), 12 parts of an oil-soluble dye (Oil Pink 314, Orient Chemical Industry Co., Ltd.), and 12 parts of an oil-soluble dye (Valifast Red 3312, Orient Chemical Industry Co., Ltd.). The total amount of the dispersion was 500 parts by mass. From the above, the total polymer component is 95 parts by mass, which is the sum of glycerin monomethacrylate (5 parts by mass), sodium 2-sulfoethyl methacrylate (5 parts by mass), cyclohexyl methacrylate monomer (30 parts by mass), n-butyl methacrylate (45 parts by mass), and crosslinker (10 parts by mass). The content of the cyclohexyl methacrylate monomer (30 parts by mass) was 31.6% by mass relative to the total polymer components (95 parts by mass) constituting the particles 2, which exceeded 30% by mass. In addition, the total amount of the oil-soluble dyes was 44 parts by mass, and the total polymer components were 95 parts by mass. When the total polymer components were converted to 100 parts by mass, the relative amount of the oil-soluble dyes as dye components was 46.3 parts by mass, which was more than 15 parts by mass. The ratio of the resin solid content (139 parts by mass) represented by the total of all polymer components (95 parts by mass) and oil-soluble dye (44 parts by mass) to the total amount of the dispersion (500 parts by mass) was 27.8% by mass. The average particle diameter of Particle 2 was 82 nm.

[0146] (Production Example 3) A dispersion of colored resin fine particles (particles 3) was obtained in the same manner as in Production Example 1, except that the distilled water was 333.5 parts, the amount of cyclohexyl methacrylate monomer was 60 parts, the amount of n-butyl methacrylate was 30 parts, and 25 parts of an oil-soluble dye (Spiron Yellow CGNH New, Hodogaya Chemical Co., Ltd.) and 11 parts of an oil-soluble dye (Valifast Yellow 1109, Orient Chemical Co., Ltd.) were used as dyes. The total amount of the dispersion was 500 parts by mass. From the above, the total polymer component is 110 parts by mass, which is the sum of glycerin monomethacrylate (5 parts by mass), 2-sulfoethyl sodium methacrylate (5 parts by mass), cyclohexyl methacrylate monomer (60 parts by mass), n-butyl methacrylate (30 parts by mass), and crosslinker (10 parts by mass). The content of the cyclohexyl methacrylate monomer (60 parts by mass) was 54.5% by mass relative to the total polymer components (110 parts by mass) constituting the particles 3, which exceeded 30% by mass. In addition, the total amount of the oil-soluble dyes was 36 parts by mass, and the total polymer components were 110 parts by mass. When the total polymer components were converted to 100 parts by mass, the relative amount of the oil-soluble dyes as dye components was 32.7 parts by mass, which was more than 15 parts by mass. The ratio of the resin solid content (146 parts by mass) represented by the total of all polymer components (110 parts by mass) and the oil-soluble dye (36 parts by mass) to the total amount of the dispersion (500 parts by mass) was 29.2% by mass. The average particle diameter of the particles 3 was 65 nm.

[0147] (Production Example 4) A dispersion of colored resin fine particles (particles 4) was obtained in the same manner as in Production Example 1, except that in Production Example 1, the amount of distilled water was 309.5 parts, the amount of cyclohexyl methacrylate monomer was 60 parts, the amount of n-butyl methacrylate was 35 parts, and the dyes used were 10 parts of an oil-soluble dye (Valifast Red 3312, Orient Chemical Industry Co., Ltd.), 25 parts of an oil-soluble dye (Valifast Black 1821, Orient Chemical Industry Co., Ltd.), and 10 parts of an oil-soluble dye (Valifast Yellow 129, Orient Chemical Industry Co., Ltd.). The total amount of the dispersion was 490 parts by mass. From the above, the total polymer component is 115 parts by mass, which is the sum of glycerin monomethacrylate (5 parts by mass), 2-sulfoethyl sodium methacrylate (5 parts by mass), cyclohexyl methacrylate monomer (60 parts by mass), n-butyl methacrylate (35 parts by mass), and crosslinker (10 parts by mass). The content of the cyclohexyl methacrylate monomer (60 parts by mass) was 52.2% by mass relative to the total polymer components (115 parts by mass) constituting the particles 4, which exceeded 30% by mass. In addition, the total amount of the oil-soluble dyes was 45 parts by mass, and the total polymer components were 115 parts by mass. When the total polymer components were converted to 100 parts by mass, the relative amount of the oil-soluble dyes as dye components was 39.1 parts by mass, which was more than 15 parts by mass. The ratio of the resin solid content (160 parts by mass) represented by the sum of all polymer components (115 parts by mass) and oil-soluble dye (45 parts by mass) to the total amount of the dispersion (490 parts by mass) was 32.7% by mass. The average particle size of Particle 4 was 132 nm.

[0148] (Production Example 5) A dispersion liquid of colored resin fine particles (particles 5) was obtained in the same manner as in Production Example 1, except that 55 parts of cyclohexyl acrylate monomer was used instead of 55 parts of cyclohexyl methacrylate monomer in Production Example 1. The total amount of the dispersion liquid was 500 parts by mass. From the above, the total polymer component is 110 parts by mass, which is the sum of glycerin monomethacrylate (5 parts by mass), sodium 2-sulfoethyl methacrylate (5 parts by mass), cyclohexyl acrylate monomer (55 parts by mass), n-butyl methacrylate (35 parts by mass), and crosslinker (10 parts by mass). The content of the cyclohexyl acrylate monomer (55 parts by mass) was 50.0% by mass relative to the total polymer components (110 parts by mass) constituting the particles 5, which exceeded 30% by mass. In addition, the amount of the oil-soluble dye was 40 parts by mass, and the total polymer components were 110 parts by mass. When the total polymer components were converted to 100 parts by mass, the relative amount of the oil-soluble dye as a dye component was 36.4 parts by mass, which was more than 15 parts by mass. The ratio of the resin solid content (150 parts by mass) represented by the sum of all polymer components (110 parts by mass) and oil-soluble dye (40 parts by mass) to the total amount of the dispersion (500 parts by mass) was 30.0% by mass. The average particle size of Particle 5 was 51 nm.

[0149] (Production Example 6) A dispersion of colored resin fine particles (particles 6) was obtained in the same manner as in Production Example 2, except that 45 parts of n-butyl methacrylate was replaced with 45 parts of methyl methacrylate in Production Example 2. The total amount of the dispersion was 500 parts by mass. From the above, the total polymer component is 95 parts by mass, which is the sum of glycerin monomethacrylate (5 parts by mass), 2-sulfoethyl sodium methacrylate (5 parts by mass), cyclohexyl methacrylate monomer (30 parts by mass), methyl methacrylate (45 parts by mass), and crosslinker (10 parts by mass). The content of the cyclohexyl methacrylate monomer (30 parts by mass) was 31.6% by mass relative to the total polymer components (95 parts by mass) constituting the particles 6, which exceeded 30% by mass. In addition, the total amount of the oil-soluble dyes was 44 parts by mass, and the total polymer components were 95 parts by mass. When the total polymer components were converted to 100 parts by mass, the relative amount of the oil-soluble dyes as dye components was 46.3 parts by mass, which was more than 15 parts by mass. The ratio of the resin solid content (139 parts by mass) represented by the total of all polymer components (95 parts by mass) and the oil-soluble dye (44 parts by mass) to the total amount of the dispersion (500 parts by mass) was 27.8% by mass. The average particle size of Particle 6 was 91 nm.

[0150] (Production Example 7) A dispersion of colored resin fine particles (particles 7) was obtained in the same manner as in Production Example 3, except that 30 parts of n-butyl methacrylate was replaced with 30 parts of styrene. The total amount of the dispersion was 500 parts by mass. From the above, the total polymer component is 110 parts by mass, which is the sum of glycerin monomethacrylate (5 parts by mass), 2-sulfoethyl sodium methacrylate (5 parts by mass), cyclohexyl methacrylate monomer (60 parts by mass), styrene (30 parts by mass), and crosslinker (10 parts by mass). The content of the cyclohexyl methacrylate monomer (60 parts by mass) was 54.5% by mass, which was greater than 30% by mass, with respect to the total polymer components (110 parts by mass) constituting the particles 7. In addition, the total amount of the oil-soluble dyes was 36 parts by mass, and the total polymer components were 110 parts by mass. When the total polymer components were converted to 100 parts by mass, the relative amount of the oil-soluble dyes as dye components was 32.7 parts by mass, which was more than 15 parts by mass. The ratio of the resin solid content (146 parts by mass) represented by the total of all polymer components (110 parts by mass) and the oil-soluble dye (36 parts by mass) to the total amount of the dispersion (500 parts by mass) was 29.2% by mass. The average particle diameter of the particles 7 was 70 nm.

[0151] (Production Example 8) A dispersion of colored resin fine particles (particles 8) was obtained in the same manner as in Production Example 4, except that the amount of distilled water was 289.5 parts, the amount of cyclohexyl methacrylate monomer was 90 parts, and the amount of n-butyl methacrylate was 25 parts. The total amount of the dispersion was 490 parts by mass. From the above, the total polymer component is 135 parts by mass, which is the sum of glycerin monomethacrylate (5 parts by mass), 2-sulfoethyl sodium methacrylate (5 parts by mass), cyclohexyl methacrylate monomer (90 parts by mass), n-butyl methacrylate (25 parts by mass), and crosslinker (10 parts by mass). The content of the cyclohexyl methacrylate monomer (90 parts by mass) was 66.7% by mass relative to the total polymer components (135 parts by mass) constituting the particles 8, which exceeded 30% by mass. In addition, the total amount of the oil-soluble dyes was 45 parts by mass, and the total polymer components were 135 parts by mass. When the total polymer components were converted to 100 parts by mass, the relative amount of the oil-soluble dyes as dye components was 33.3 parts by mass, which was more than 15 parts by mass. The ratio of the resin solid content (180 parts by mass) represented by the sum of all polymer components (135 parts by mass) and oil-soluble dye (45 parts by mass) to the total amount of the dispersion (490 parts by mass) was 36.7% by mass. The average particle size of particles 8 was 110 nm.

[0152] (Production Example 9) A dispersion of colored resin fine particles (particles 9) was obtained in the same manner as in Production Example 1 above, except that the distilled water was 339.5 parts and the crosslinking agent was 0 (zero) parts (not used). The total amount of the dispersion was 500 parts by weight. From the above, the total polymer component is 100 parts by mass, which is the sum of glycerin monomethacrylate (5 parts by mass), 2-sulfoethyl sodium methacrylate (5 parts by mass), cyclohexyl methacrylate monomer (55 parts by mass), n-butyl methacrylate (35 parts by mass), and crosslinker (0 parts by mass). The content of the cyclohexyl methacrylate monomer (55 parts by mass) was 55.0% by mass, which was greater than 30% by mass, based on the total polymer components (100 parts by mass) constituting the particles 9. The amount of the oil-soluble dye was 40 parts by mass, and the total polymer components was 100 parts by mass, but the relative amount of the oil-soluble dye as a dye component to the total polymer components was 40.0 parts by mass, which was more than 15 parts by mass. The ratio of the resin solid content (140 parts by mass) represented by the sum of all polymer components (100 parts by mass) and oil-soluble dye (40 parts by mass) to the total amount of the dispersion (500 parts by mass) was 28.0% by mass. The average particle diameter of the particles 9 was 40 nm.

[0153] (Production Example 10) Polymerization was carried out in the same manner as in Production Example 2 above, except that no cyclohexyl methacrylate monomer was used (content: zero) and 75 parts of n-butyl methacrylate was used. However, since a large amount of dye was used and no cyclohexyl methacrylate monomer was used, good polymerization could not be achieved. The content of the oil-soluble dye (44 parts by mass) was 46.3% by mass based on the total polymer components (95 parts by mass).

[0154] (Production Example 11) Polymerization was carried out in the same manner as in Production Example 3, except that no cyclohexyl methacrylate monomer was used (content: zero) and n-butyl methacrylate was used in an amount of 90 parts. However, since a large amount of dye was used and no cyclohexyl methacrylate monomer was used, good polymerization could not be achieved. The content of the oil-soluble dye (36 parts by mass) was 32.7% by mass based on the total polymer components (110 parts by mass).

[0155] (Production Example 12) A dispersion of colored resin fine particles (particles 12) was obtained in the same manner as in Production Example 4, except that the amount of cyclohexyl methacrylate monomer was 30 parts and the amount of n-butyl methacrylate was 65 parts in Production Example 4. The total amount of the dispersion was 490 parts by mass. From the above, the total polymer component is 115 parts by mass, which is the sum of glycerin monomethacrylate (5 parts by mass), sodium 2-sulfoethyl methacrylate (5 parts by mass), cyclohexyl methacrylate monomer (30 parts by mass), n-butyl methacrylate (65 parts by mass), and crosslinker (10 parts by mass). The content of the cyclohexyl methacrylate monomer (30 parts by mass) was 26.1% by mass, which was lower than 30% by mass, with respect to the total polymer components (115 parts by mass) constituting the particles 12. In addition, the total amount of the oil-soluble dyes was 45 parts by mass, and the total polymer components were 115 parts by mass. When the total polymer components were converted to 100 parts by mass, the relative amount of the oil-soluble dyes as dye components was 39.1 parts by mass, which was more than 15 parts by mass. The ratio of the resin solid content (160 parts by mass) represented by the sum of all polymer components (115 parts by mass) and oil-soluble dye (45 parts by mass) to the total amount of the dispersion (490 parts by mass) was 32.7% by mass. The average particle size of the particles 12 was 85 nm.

[0156] <Ink Preparation> Using the dispersions of the colored resin particles produced in Production Examples 1 to 9 and 12 above, inks can be prepared according to the formulations shown in Table 1 below in a conventional manner.

[0157] [Table 1]

[0158] The inks obtained above were evaluated for stability over time by the following evaluation method.

[0159] (Method for evaluating stability over time) Each ink obtained above was filled into a glass vial, the lid was closed, and the ink was stored in an environment of 50°C. The period during which no aggregation or sedimentation was observed in the ink in the vial after a certain period of time was defined as the "period during which stability was maintained" and was evaluated according to the following evaluation criteria. That is, the period was 6 months or more, and was rated as "A". The period was 3 months or more but less than 6 months, and was rated as "B". The period was rated as "C" for less than 3 months. The results are shown in Table 2 below. Note that since good polymerization could not be achieved in Production Examples 10 and 11, evaluation according to this evaluation criteria was not possible, and therefore the evaluation column in Table 2 below was marked as "-".

[0160] [Table 2]

[0161] From Table 2 above, it can be seen that the inks using the colored resin particles of Production Examples 1 to 9, which are within the scope of the present invention, have superior stability over time compared to the ink using the colored resin particles of Production Example 12, which is outside the scope of the present invention. Furthermore, when Production Examples 1 to 7 are compared with Production Examples 8 and 9, Production Example 8 has a higher content of cyclohexyl methacrylate monomer than Production Examples 1 to 7, and Production Example 9 does not contain a crosslinking agent, and in these cases, the evaluation of stability over time tends to be slightly inferior.

[0162] <Relationship between the inner diameter of the tip opening of the second writing part and the outer diameter of the flow passage of the first writing part> Using the dispersions of colored resin particles of Production Examples 2 and 3 described above, two types of ink, ink A and ink B, were prepared according to the formulations shown in Table 1 above, in a conventional manner.

[0163] The inner diameter of the tip opening 31A of the second writing part 30 from which the tip part 23 of the first writing part 20 protrudes is W1 (mm), and the outer diameter of the flow path of the first writing part 20 is W2 (mm). Experiments were conducted to verify the state of smearing of drawn lines using the above two types of ink for each of the writing instruments 1 of Examples 1 and 2 and the writing instrument of the Comparative Example, and the results are shown in Table 3 below. The surface tension of ink A was 37 mN / m and the viscosity was 3.1 mPa s. The surface tension of ink B was 35 mN / m and the viscosity was 2.9 mPa s. In Table 3 below, the inventors drew a circle of about 5 cm in diameter about five times, and the drawn lines were evaluated as "A" when no smearing was observed, and "B" when slight smearing was observed.

[0164] [Table 3]

[0165] Example 1 In Example 1, W1 = 0.47 mm, W2 = 0.56 mm. As a result, W1-W2 = -0.09 mm, which was less than 0. As for the drawn lines, no smearing was observed for any of the types of ink used, and the results were good.

[0166] Example 2 In Example 2, W1=0.55 mm and W2=0.60 mm. As a result, W1-W2=-0.05 mm. The evaluation was almost the same as in Example 1.

[0167] (Comparative Example) In the comparative example, W1 = 1.0 mm, W2 = 0.49 mm. As a result, W1-W2 = 0.51 mm, which is greater than 0.5 mm. As for the drawn lines, fading was observed for all ink types. In conclusion, it was judged to be undesirable.

[0168] In this way, it was found that when the value (W1-W2) obtained by subtracting the outer diameter W2 of the flow path of the first writing part 20 from the inner diameter W1 of the tip opening 31A of the second writing part 30 from which the tip 23 of the first writing part 20 protrudes is 0.5 mm or less, even if any smearing of the drawn line is observed, it is slight, and when it is less than 0, no smearing is observed.

[0169] From the above results, it was found that, with regard to the relationship between the inner diameter W1 of the tip opening 31A of the second writing part 30 and the outer diameter W2 of the flow path 22 of the first writing part 20, the value obtained by subtracting the outer diameter W2 of the flow path of the first writing part 20 from the inner diameter W1 of the tip opening 31A of the second writing part 30 from which the tip part 23 of the first writing part 20 protrudes is desirably 0.5 mm or less, and more desirably less than 0.

[0170] <Line width> Here, for the writing implement 1 (W1=0.47mm, W2=0.56mm) according to the above-mentioned Example 1, three samples were prepared for each of ink A and ink B, and writing was performed in a spiral shape on the surface of wood-free paper at a writing speed of 4.5m / min, a writing load of 0.98N (100g weight), and writing angles of 60° and 90°, the width of the written line was measured, and the ratio of the drawn line width was calculated. The results are shown in Table 4 below.

[0171] [Table 4]

[0172] As described above, for all samples, under the same writing load, the value obtained by dividing the line width at a writing angle of 60° to the writing surface by the line width at a writing angle of 90° to the writing surface was around 1.00, which is greater than 0.67 and less than 1.5. Therefore, the change in line width was able to be kept within a certain range. [Industrial Applicability]

[0173] The present invention can be used in a writing instrument that allows the width of a drawn line to be changed when writing. [Explanation of symbols]

[0174] 1 writing implements 10 shaft cylinder 11 Tip shaft 11A Base part 11A1 Locking protrusion 11B Reduced diameter part 11C Tip part 11D Locking surface 11E Air replacement vent 12 Rear shaft 12A Front grip part 12A1 Rib 12A2 Outer projection 12B Rear grip part 12B1 Fixed projection 12C Boundary 12D Slot 12E End 13 front opening 14 rear opening 15 ink reservoir 20: first writing portion; 21: outer peripheral portion; 22: flow path 23 Front end 24 Rear end 25 Body 26 Step 27 Annular groove 30 Second writing part 30A Tip part 30B Center part 30C rear end 31: narrowed portion; 31A: tip opening; 31B: opening periphery 32 cylindrical portion 33 engaging portion 33A engaging piece 34 Elastic portion 35 Cylinder portion 35A Rear opening 36 Punch fixing part 36A Protrusion 37 Penetration part 37A 1st penetration part 37A1 Stopping surface 37B 2nd penetration part 37C 3rd penetration part 40 gripping member 41 inner recess 42 front opening 42A Edge 43 Rear opening 43A End face 44 Locking piece 50 Cap 51 Cap outer cylinder 52 Cap inner cylinder 52A Connection portion 52B Discontinuous edge 53 Circumferential groove 53A Through hole 54 Rear opening 54A Inner edge 55 Locking protrusion 56 Guide piece 60 tail plug 61 insertion portion 62 flange portion 63 Head 64 Tail 70 Extension 100 Case 101 Case Molding 110 Storage section 111 Tray part 111A Tray side 111B Side hole 112 Lid 112A Lid side 112B Side protrusion 113 Recess 114 Partition 115 Curved surface 116 leading edge 117 connecting portion 120 opening 121 hinge portion 122 opening edge 125 Reinforcing ribs 130 Support piece 130A Thin wall part 131 Engagement hole 131A Engagement projection 132 Locking edge 133 Engagement protrusion 150 Movable part 151 Contact edge 152 Engagement protrusion 153 Engagement groove 153A Engagement hole 155 Flat surface 160 Window 200 Writing set H1 Protrusion dimension W1 Inner diameter of tip opening W2 Outer diameter of flow passage

Claims

1. A case for storing a writing instrument, comprising: The case is a storage section for storing the writing instrument so that the writing instrument can be taken in and out through a rectangular opening; a hinge portion provided on one of the long sides of the opening; Two opening edges which are both short sides of the opening; a movable portion that is connected to the storage portion via the hinge portion and is rotatable between a closed position and an open position with respect to the opening portion; two abutment edges in the movable portion that abut against the two opening edges, respectively, in the closed position; a support piece protruding from an inner surface side of the opening edge toward the movable part; a locking edge which is a side of the support piece facing the hinge portion; a fitting protrusion protruding outwardly from the vicinity of the locking edge of the support piece; an engaging projection that protrudes inward near the abutment edge of the movable portion and abuts against the locking edge in the open position; an engagement hole formed in the vicinity of the contact edge of the movable portion, into which the engagement projection is fitted when the movable portion is in the closed position; A case for storing a writing instrument, comprising:

2. A case for storing the writing instrument according to claim 1; A shaft cylinder, an ink storage section for storing ink inside the barrel; a first writing part that is accommodated in the barrel at a tip end side and that guides the ink from the ink storage part by capillary force; a second writing part attached to a tip of the barrel, through which the first writing part passes and from which a tip of the first writing part protrudes; A writing instrument having A writing instrument set comprising:

3. A case for storing the writing instrument according to claim 1; A writing instrument having a barrel, the barrel being shaped so that a cross section in the transverse direction is generally a rounded rectangle; A writing instrument set comprising:

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