JP7516476B2 - Writing implements - Google Patents

Description

The present invention relates to a writing instrument.

Writing instruments such as ballpoint pens are often equipped with clips. The clip serves the purpose of preventing the writing instrument from rolling and of holding items (paper, clothing, etc.) between the barrel and the clip.

Conventionally, there is known a writing instrument in which the distance between the clip and the barrel can be changed by swinging the clip relative to the barrel (Patent Documents 1 and 2). In such a writing instrument, the clip is biased by a coil spring, and when moving the clip away from the barrel, the coil spring is compressed by a person's finger.

However, if the coil spring is not held firmly in place, repeated expansion and contraction of the coil spring may cause it to come off the writing instrument. In response to this, the writing instruments described in Patent Documents 1 and 2 are provided with a spring holder onto which the coil spring is inserted, and most of the coil spring is covered by a clip. This restricts movement of the coil spring other than expansion and contraction, preventing the coil spring from coming off the writing instrument.

JP 2006-130800 A JP 2014-58120 A

However, in such writing instruments, the opening of the space in which the coil spring is placed is very narrow, so the coil spring needs to be significantly compressed in order to be attached to the writing instrument. This makes it difficult to attach the coil spring to the writing instrument, and reduces the productivity of the writing instrument.

In view of the above problems, the object of the present invention is to prevent a coil spring from coming off a writing instrument, while ensuring the ease of attachment of the coil spring to the writing instrument, in a writing instrument equipped with a coil spring that biases a clip.

In order to solve the above problem, in a first aspect, a writing instrument is provided that includes a barrel, a clip swingably connected to the barrel, and a coil spring that is disposed between the barrel and the clip and biases the clip, and a spring retaining portion onto which the coil spring is inserted is provided on at least one of the barrel and the clip, and the writing instrument is characterized in that a protrusion is provided on the side of the spring retaining portion.

It is also preferable that the protrusion be located at a distance from the base end of the spring retaining portion.

It is also preferable that the protrusion be provided at the front of the spring retaining portion.

In the second aspect, the protrusion in the first aspect includes a first protrusion provided at the base end of the spring holding portion and a second protrusion provided at a position spaced apart from the base end of the spring holding portion, and the first protrusion and the second protrusion are spaced apart in the circumferential direction of the spring holding portion.

In the third aspect, a spring support part that is disposed in front of the coil spring and supports the front end of the coil spring in the first or second aspect is provided on the shaft tube or clip.

In the fourth aspect, the device further includes a clip holder that holds the clip, and the width of the inner surface of the clip is shorter than the width of the side surface of the clip holder.

According to the present invention, in a writing instrument equipped with a coil spring that biases a clip, it is possible to prevent the coil spring from coming off the writing instrument while ensuring the ease of attachment of the coil spring to the writing instrument.

FIG. 1 is a front view of a writing instrument according to an embodiment of the present invention. FIG. 2 is a front cross-sectional view of the writing instrument of FIG. FIG. 3 is a front view of the inner cylinder, the clip, and the first coil spring when the clip is not operated. FIG. 4 is a front view of the inner cylinder, the clip, and the first coil spring when the clip is being operated. FIG. 5 is a perspective view of the inner cylinder. FIG. 6 is a front view of the inner cylinder. FIG. 7 is a plan view of the inner cylinder. FIG. 8 is an enlarged front view of the spring holding portion. FIG. 9 is a perspective view of the clip. FIG. 10 is a front view of the clip. FIG. 11 is a bottom view of the clip. FIG. 12 is a front cross-sectional view of the inner cylinder, the clip, and the first coil spring when the clip is being operated. FIG. 13 is a left side view of the clip. FIG. 14 is an enlarged view of part A in FIG. 13 when the protruding portion is in contact with the rear barrel. FIG. 15 is a front view showing an embodiment different from that shown in FIG. 1, in which a clip is connected to an inner cylinder. FIG. 16 is a perspective view of the inner cylinder. FIG. 17 is a perspective view of the clip. FIG. 18 is a front view showing a state in which the clip is temporarily fastened before being connected to the inner cylinder. FIG. 19 is a cross-sectional view of the state before the clip is provisionally fastened to the inner cylinder. FIG. 20 is a cross-sectional view taken along line LL in FIG.

The present invention will now be described with reference to the accompanying drawings, in which the same or similar components are designated by the same reference numerals.

The configuration of the writing instrument 1 will be briefly described below with reference to Figs. 1 and 2. Fig. 1 is a front view of the writing instrument 1 according to an embodiment of the present invention. Fig. 2 is a front cross-sectional view of the writing instrument 1 of Fig. 1. In this embodiment, the writing instrument 1 is a knock-type ballpoint pen. In this specification, as shown in Fig. 1, in the axial direction (longitudinal direction) of the writing instrument 1, the tip, i.e., the pen tip side, is defined as the "front" side, and the side of the writing instrument 1 opposite the pen tip is defined as the "rear" side.

The writing instrument 1 comprises a front barrel 2, a rear barrel 3 arranged behind the front barrel 2, an inner barrel 4 arranged behind the rear barrel 3, a clip 5 swingably connected to the inner barrel 4, and a first coil spring 6 that biases the clip 5. The front barrel 2, the rear barrel 3, the inner barrel 4, and the clip 5 are made of a resin material. In this specification, the front barrel 2, the rear barrel 3, and the inner barrel 4 are collectively referred to as the barrel. Note that the front barrel 2, the rear barrel 3, and the inner barrel 4, the front barrel 2 and the rear barrel 3, or the rear barrel 3 and the inner barrel 4 may be integral.

The writing instrument 1 further includes a refill 7 disposed inside the front barrel 2 and the rear barrel 3, a second coil spring 8 that biases the refill 7 rearward, an erasing member 9 for erasing handwriting, and a cover member 10 that covers the erasing member 9. The erasing member 9 and the cover member 10 are disposed at the rear end of the writing instrument 1.

The refill 7 has an ink containing tube that contains ink, and a writing part 71 is attached to the front end of the ink containing tube. When the cover member 10 is pressed with a finger while the writing part 71 is retracted into the front barrel 2, the refill 7 moves forward against the biasing force of the second coil spring 8, and the writing part 71 protrudes from the front barrel 2. On the other hand, when the cover member 10 is pressed again with a finger while the writing part 71 protrudes from the front barrel 2, the refill 7 moves backward due to the biasing force of the second coil spring 8, and the writing part 71 retracts into the front barrel 2.

The configuration of the inner tube 4, clip 5, and first coil spring 6 will be described in detail below. Figure 3 is a front view of the inner tube 4, clip 5, and first coil spring 6 when the clip 5 is not being operated. Figure 4 is a front view of the inner tube 4, clip 5, and first coil spring 6 when the clip 5 is being operated. Other parts of the writing instrument 1 are omitted in Figures 3 and 4. The state in Figure 3 is the same as the state in Figure 1.

The first coil spring 6 is disposed between the inner tube 4 and the clip 5, and biases the clip 5 so that the front end of the clip 5 approaches the rear barrel 3. The first coil spring 6 extends approximately perpendicular to the axial direction of the writing instrument 1. As shown in FIG. 1, when the clip 5 is not being operated, the front end of the clip 5 abuts against the rear barrel 3 due to the biasing force of the first coil spring 6.

On the other hand, as shown in Figure 4, when the rear end of the clip 5 is pressed toward the center of the shaft with a finger or the like, the first coil spring 6 is compressed. As a result, the clip 5 swings and the front end of the clip 5 moves away from the rear barrel 3. In this state, items (paper, clothes, etc.) can be easily inserted between the clip 5 and the rear barrel 3.

When the front end of the clip 5 is separated from the rear barrel 3 and an object is inserted between the clip 5 and the rear barrel 3, the clip 5 swings due to the biasing force of the first coil spring 6, and the front end of the clip 5 presses against the object. As a result, the object is sandwiched between the clip 5 and the rear barrel 3.

Figure 5 is a perspective view of the inner cylinder 4, Figure 6 is a front view of the inner cylinder 4, and Figure 7 is a plan view of the inner cylinder 4. The inner cylinder 4 has a front cylinder portion 41 that is inserted into the rear cylinder 3, a rear cylinder portion 42 that is positioned outside the rear cylinder 3, and a clip holding portion 43 that holds the clip 5.

The clip holding portion 43 is provided with two engagement protrusions 44 that are inserted into engagement holes 53a of the clip 5 described below. The engagement protrusions 44 have a generally cylindrical shape and protrude from the clip holding portion 43 in a direction perpendicular to the axial direction of the writing instrument 1. The clip 5 is swingably connected to the inner tube 4 via the engagement protrusions 44. The engagement protrusions 44 function as a swing fulcrum when the clip 5 swings.

The rear tubular portion 42 is provided with a spring retaining portion 45 into which the first coil spring 6 is inserted. The spring retaining portion 45 has a generally cylindrical shape and protrudes from the rear tubular portion 42 radially outward of the inner tube 4. The spring retaining portion 45 is divided into two portions, a front portion 45a and a rear portion 45b. The front portion 45a is located forward of the rear portion 45b (toward the front tubular portion 41).

Figure 8 is an enlarged front view of the spring retaining portion 45. The tip of the spring retaining portion 45 has a tapered shape that narrows toward the tip of the spring retaining portion 45. This makes it easy to insert the first coil spring 6 into the spring retaining portion 45.

The side surface of the spring retaining portion 45 is provided with a protrusion that protrudes radially outward from the spring retaining portion 45. Specifically, two first protrusions 45c are provided on the side surfaces of the front portion 45a and the rear portion 45b, and one second protrusion 45d is provided on the side surface of the front portion 45a. The first protrusion 45c is provided at the base end of the spring retaining portion 45. On the other hand, the second protrusion 45d is provided at a position spaced apart from the base end of the spring retaining portion 45, specifically between the base end and the tip end of the spring retaining portion 45. The second protrusion 45d is also located at the front end of the spring retaining portion 45.

The first protrusion 45c engages with the end of the first coil spring 6 that is inserted into the spring holding portion 45. The second protrusion 45d engages with the first coil spring 6 when the first coil spring 6 attempts to come off the spring holding portion 45. Therefore, the first protrusion 45c and the second protrusion 45d can prevent the first coil spring 6 from coming off the spring holding portion 45, i.e., the first coil spring 6 from coming off the writing instrument 1.

In addition, when the first coil spring 6 is compressed by operating the clip 5, more force is applied to the rear end of the first coil spring 6, so that the front end of the first coil spring 6 tends to float up from the base end of the spring holding portion 45. In contrast, in this embodiment, the second protrusion 45d is provided on the front portion 45a of the spring holding portion 45. This makes it possible to prevent the front end of the first coil spring 6 from floating up from the base end of the spring holding portion 45, and therefore makes it possible to further prevent the first coil spring 6 from coming off the spring holding portion 45.

As can be seen from FIG. 7, the first protrusion 45c and the second protrusion 45d are spaced apart in the circumferential direction of the spring retaining portion 45. This makes it possible to increase the holding force of the first coil spring 6 over a wide range in the circumferential direction of the spring retaining portion 45. This makes it possible to further prevent the first coil spring 6 from coming off the spring retaining portion 45.

In addition, the tip portions of the first protrusion 45c and the second protrusion 45d (portions on the tip side of the spring holding portion 45) have a tapered shape that narrows toward the tip of the spring holding portion 45. This makes it possible to prevent the first protrusion 45c and the second protrusion 45d from deteriorating the attachment of the first coil spring 6 to the spring holding portion 45.

The second protrusion 45d may be provided not only on the front portion 45a, but also on the side surfaces of the front portion 45a and the rear portion 45b. The first protrusion 45c or the second protrusion 45d may be omitted. The spring retaining portion 45 may have an integral shape without being divided into the front portion 45a and the rear portion 45b. In this case, too, the portion located on the front side of the spring retaining portion 45 (the front tubular portion 41 side) is referred to as the front portion of the spring retaining portion 45. The spring retaining portion 45 may have a substantially polygonal prism shape.

A protrusion 46 is formed on the outer peripheral surface of the front tube portion 41. In addition, two grooves 47 extending along the axial direction of the writing instrument 1 are formed on the outer peripheral surface of the front tube portion 41 near the protrusion 46. The two grooves 47 penetrate the front tube portion 41. The two grooves 47 are formed independently without communicating with each other. Furthermore, the two grooves 47 are arranged on both sides of the protrusion 46 in the circumferential direction. In other words, the protrusion 46 is formed on a doubly supported beam portion 48 that is defined by the two grooves 47 and has both ends supported. The protrusion 46 is arranged in the center of the axial length of the doubly supported beam portion 48. However, it is preferable that the rear end of the protrusion 46 is arranged rearward of the center of the axial length of the doubly supported beam portion 48.

When the front tube portion 41 is inserted into the rear barrel 3, the protrusion 46 of the inner tube 4 is inserted into the through hole formed in the rear barrel 3, completing the assembly (Fig. 2). Since two grooves 47 are formed near the protrusion 46 of the inner tube 4, that is, since the protrusion 46 is formed on the double-supported beam portion 48, when the front tube portion 41 of the inner tube 4 is inserted into the rear barrel 3, the protrusion 46 abuts against the inner edge of the rear end opening of the rear barrel 3, and the double-supported beam portion 48 elastically deforms radially inward. This makes it easier to insert the inner tube 4 into the rear barrel 3. In other words, the elasticity of the double-supported beam portion 48 can be adjusted by adjusting the length and shape of the two grooves 47 and adjusting the circumferential length of the double-supported beam portion 48, i.e., the width and axial length. In addition, since the protrusion 46 is formed on the double-supported beam portion 55 rather than on a cantilever beam, excessive bending and creep deformation do not occur.

Figure 9 is a perspective view of clip 5, Figure 10 is a front view of clip 5, and Figure 11 is a bottom view of clip 5. Clip 5 has a clip body 51, two protrusions 52, and two side wall portions 53 adjacent to protrusions 52. Protrusions 52 protrude from clip body 51 toward rear barrel 3 so as to contact rear barrel 3. The plate thickness of protrusions 52 and side wall portions 53 is approximately equal to the plate thickness of clip body 51.

The side wall portion 53 is provided with an engagement hole 53a into which the engagement protrusion 44 of the inner tube 4 is inserted. The rear end of the side wall portion 53 covers the side of the first coil spring 6. This makes it possible to suppress radial movement of the first coil spring 6. This makes it possible to further suppress the first coil spring 6 from coming off the spring retaining portion 45.

When the clip body 51 is attached to the inner tube 4, it extends along the barrel (the inner tube 4 and the rear barrel 3). The clip body 51 is provided with a swing restriction portion 51a and a spring support portion 51b.

The swing restriction portion 51a has a cylindrical shape and protrudes from the clip body 51 toward the inner tube 4. FIG. 12 is a front cross-sectional view of the inner tube 4, the clip 5, and the first coil spring 6 when the clip 5 is being operated. As shown in FIG. 12, the swing restriction portion 51a abuts against the clip holding portion 43 when the clip 5 is operated, and restricts the swing range of the clip 5 when it leaves the rear barrel 3.

As can be seen from FIG. 11, the spring support portion 51b has an arc shape in a cross section perpendicular to the extension direction of the first coil spring 6, and protrudes from the clip body 51 toward the inner tube 4. The inner diameter of the arc is approximately equal to the outer diameter of the first coil spring 6. The spring support portion 51b is disposed on the front side of the first coil spring 6 (the pen tip side of the writing instrument 1) and supports the front end portion of the first coil spring 6. This makes it possible to suppress radial movement of the first coil spring 6. This makes it possible to further suppress the first coil spring 6 from coming off the spring retaining portion 45.

In this embodiment, no member for supporting the first coil spring 6 is provided on the rear side of the first coil spring 6. Therefore, it is not necessary to significantly compress the first coil spring 6 in order to attach the first coil spring 6 to the writing instrument 1. Therefore, it is possible to ensure that the first coil spring 6 can be easily attached to the writing instrument 1.

Furthermore, it is preferable that the height h (see FIG. 8) of the spring retaining portion 45 of the inner tube 4 is less than 1/2 the length of the first coil spring 6 when the clip 5 is not operated, i.e., the distance between the rear tube portion 42 of the inner tube 4 and the clip body 51 when the clip 5 is not operated. This makes it easier to insert the first coil spring 6 into the spring retaining portion 45, and thus improves the attachment of the first coil spring 6 to the writing instrument 1. In this embodiment, the height h of the spring retaining portion 45 of the inner tube 4 is approximately 1/3 the length of the first coil spring 6 when the clip 5 is not operated.

The protruding portion 52 of the clip 5 is connected to the side wall portion 53 and extends approximately parallel to the axial direction of the writing instrument 1. Figure 13 is a left side view of the clip 5. Figure 14 is an enlarged view of part A in Figure 13 when the protruding portion 52 is in contact with the rear barrel 3.

A parting line PL is formed on the protruding portion 52. The clip 5 is molded using a three-way split mold that opens in three directions, left and right and bottom, in the plane of FIG. 13. The block that opens downward is a slide mold used to mold the inner surface of the clip 5, such as the swing restriction portion 51a and the spring support portion 51b. The parting line PL shown in FIG. 14 is the mating surface between the block that opens downward and the block that opens to the left.

A linear protrusion is left on the parting line PL. In addition, burrs are likely to occur at the position where the parting line PL is formed. Therefore, if the parting line PL or burrs come into contact with the rear barrel 3, the outer surface of the rear barrel 3 may be damaged. In this embodiment, the outer surface of the rear barrel 3 is subjected to surface treatment such as transfer printing, painting, and decoration. Therefore, the outer surface of the rear barrel 3 is easily damaged by the protruding portion 52 of the clip 5. However, in this embodiment, the parting line PL is formed on the part of the protruding portion 52 that does not come into contact with the rear barrel 3. Therefore, it is possible to prevent burrs generated on the parting line PL from coming into contact with the rear barrel 3, and therefore to prevent the outer surface of the rear barrel 3 from being damaged by the protruding portion 52.

The inner end 52a and outer end 52b of the protrusion 52 have an R-shape. The inner end 52a of the protrusion 52 corresponds to the portion of the protrusion 52 that contacts the rear barrel 3. Because the portion that contacts the rear barrel 3 is R-shaped, it is possible to prevent the protrusion 52 from damaging the outer surface of the rear barrel 3. In this specification, in the direction perpendicular to the axial direction of the writing instrument 1 and the protruding direction of the protrusion 52 (the left-right direction in Figures 13 and 14), the side closer to the axis of the writing instrument 1 is defined as the "inner" side, and the side farther from the axis of the writing instrument 1 is defined as the "outer" side.

In addition, in this embodiment, the straight portion 52d is between the R-shape of the inner end portion 52a and the parting line PL. This allows the parting line PL to be separated from the rear barrel 3, and further prevents the parting line PL and burrs generated on the parting line PL from coming into contact with the rear barrel 3.

In addition, in this embodiment, a step 52c is provided at the parting line PL. This prevents burrs from protruding from the bottom surface of the protruding portion 52 (the surface closest to the axis of the writing instrument 1 in the protruding direction of the protruding portion 52). Furthermore, the step 52c faces the side opposite the portion of the protruding portion 52 that contacts the rear barrel 3 in a direction perpendicular to the axial direction of the writing instrument 1 and the protruding direction of the protruding portion 52. This prevents the step 52c from contacting the rear barrel 3 and damaging the rear barrel 3. In this embodiment, the height of the step 52c is 20 μm to 40 μm.

The two protrusions 52 are symmetrical with respect to the X-X plane in FIG. 13. Therefore, the other protrusion 52, not shown in FIG. 14, also has a parting line, which is the mating surface between the block that opens downward and the block that opens to the right, and a step is provided at the parting line.

Although the preferred embodiment of the present invention has been described above, the present invention is not limited to the above embodiment, and various modifications and changes can be made within the scope of the claims. For example, the writing instrument 1 may be another writing instrument such as a mechanical pencil.

The spring retaining portion 45 may be provided on the clip 5 or on the shaft tube (inner tube 4) and the clip 5. That is, the spring retaining portion 45 is provided on at least one of the shaft tube (inner tube 4) and the clip 5. The spring support portion 51b may be omitted or provided on the shaft tube (inner tube 4). The number of protrusions 52 on the clip 5 may be one or three or more.

The refill 7 may also contain thermochromic ink that contains a thermochromic coloring material. In this case, the writing instrument 1 is a thermochromic writing instrument, and the writing of the writing instrument 1 can be thermochromic due to frictional heat generated when rubbed by the friction body serving as the erasing member 9.

Here, thermochromic ink refers to ink that has the property of maintaining a predetermined color (first color) at room temperature (e.g., 25°C), changing to another color (second color) when heated to a predetermined temperature (e.g., 60°C), and then returning to the original color (first color) when cooled to a predetermined temperature (e.g., -20°C). In a writing instrument 1 using thermochromic ink, the second color is made colorless, and the term "erasing" refers to heating a line drawn in the first color (e.g., red) to make it colorless. Therefore, the line is rubbed against the writing surface on which it was drawn with a friction body to generate frictional heat, which changes the drawn line to colorless, i.e., erases it. Of course, the second color may be a color other than colorless. It is also preferable that the temperature difference from the first color to the second color is 70°C or more.

The thermochromic microencapsulated pigment that serves as the thermochromic coloring material is not particularly limited as long as it has the ability to change color due to heat such as frictional heat, for example, from colored to colorless, from colored to colored, or from colorless to colored, and various types can be used, and examples of such materials include microencapsulated thermochromic compositions that contain at least a leuco dye, a color developer, and a color change temperature regulator.

The leuco dyes that can be used are not particularly limited as long as they are electron donating dyes that function as color formers. Specifically, in order to obtain inks with excellent color development properties, conventionally known dyes such as triphenylmethane, spiropyran, fluoran, diphenylmethane, rhodamine lactam, indolylphthalide, and leucoauramine can be used alone (one type) or in a mixture of two or more types (hereinafter simply referred to as "at least one type").

Specifically, 6-(dimethylamino)-3,3-bis[4-(dimethylamino)phenyl]-1(3H)-isobenzofuranone, 3,3-bis(p-dimethylaminophenyl)-6-dimethylaminophthalide, 3-(4-diethylaminophenyl)-3-(1-ethyl-2-methylindol-3-yl)phthalide, 3-(4-diethylamino-2-ethoxyphenyl)-3-(1-ethyl-2-methylindol-3-yl)-4 -Azaphthalide, 1,3-dimethyl-6-diethylaminofluoran, 2-chloro-3-methyl-6-dimethylaminofluoran, 3-dibutylamino-6-methyl-7-anilinofluoran, 3-diethylamino-6-methyl-7-anilinofluoran, 3-diethylamino-6-methyl-7-xylidinofluoran, 2-(2-chloroanilino)-6-dibutylaminofluoran, 3,6-dimethoxyfluoran, 3,6-di- n-Butoxyfluoran, 1,2-Benz-6-diethylaminofluoran, 1,2-Benz-6-dibutylaminofluoran, 1,2-Benz-6-ethylisoamylaminofluoran, 2-Methyl-6-(N-p-tolyl-N-ethylamino)fluoran, 2-(N-phenyl-N-methylamino)-6-(N-p-tolyl-N-ethylamino)fluoran, 2-(3'-trifluoromethylanilino)-6-diethylamino Fluoran, 3-chloro-6-cyclohexylaminofluoran, 2-methyl-6-cyclohexylaminofluoran, 3-di(n-butyl)amino-6-methoxy-7-anilinofluoran, 3,6-bis(diphenylamino)fluoran, methyl-3',6'-bisdiphenylaminofluoran, chloro-3',6'-bisdiphenylaminofluoran, 3-methoxy-4-dodecoxystyrinoquinoline, etc.

These leuco dyes have a lactone skeleton, a pyridine skeleton, a quinazoline skeleton, a bisquinazoline skeleton, etc., and color is generated by opening these skeletons (rings).

The color developer that can be used is a component that has the ability to cause the leuco dye to develop color, and examples of such compounds include phenolic resin compounds, salicylic acid metal chlorides, salicylic acid resin metal salt compounds, and solid acid compounds.

Specifically, o-cresol, tertiary butyl catechol, nonylphenol, n-octylphenol, n-dodecylphenol, n-stearylphenol, p-chlorophenol, p-bromophenol, o-phenylphenol, hexafluorobisphenol, n-butyl p-hydroxybenzoate, n-octyl p-hydroxybenzoate, resorcinol, dodecyl gallate, 2,2-bis(4'-hydroxyphenyl)propane, 4,4-dihydroxydiphenyl sulfone, 1,1-bis(4'-hydroxyphenyl)ethane, 2,2-bis(4'-hydroxy-3-methylphenyl)propane, bis(4-hydroxyphenyl)sulfide, 1-phenyl-1,1-bis( 1,1-bis(4'-hydroxyphenyl)ethane, 1,1-bis(4'-hydroxyphenyl)-3-methylbutane, 1,1-bis(4'-hydroxyphenyl)-2-methylpropane, 1,1-bis(4'-hydroxyphenyl)n-hexane, 1,1-bis(4'-hydroxyphenyl)n-heptane, 1,1-bis(4'-hydroxyphenyl)n-octane, 1,1-bis(4'-hydroxyphenyl)n-nonane, 1,1-bis(4'-hydroxyphenyl)n-decane, 1, At least one of 1-bis(4'-hydroxyphenyl)n-dodecane, 2,2-bis(4'-hydroxyphenyl)butane, 2,2-bis(4'-hydroxyphenyl)ethylpropionate, 2,2-bis(4'-hydroxyphenyl)-4-methylpentane, 2,2-bis(4'-hydroxyphenyl)hexafluoropropane, 2,2-bis(4'-hydroxyphenyl)n-heptane, and 2,2-bis(4'-hydroxyphenyl)n-nonane may be mentioned.

The amount of developer used can be selected according to the desired color density and is not particularly limited, but it is usually preferable to select an amount within the range of about 0.1 to 100 parts by weight per 1 part by weight of the above-mentioned leuco dye.

The discoloration temperature regulator that can be used is a substance that controls the discoloration temperature in the color development of the leuco dye and the color developer. The discoloration temperature regulator that can be used is a conventionally known one. Specific examples include alcohols, esters, ketones, ethers, acid amides, azomethines, fatty acids, and hydrocarbons.

More specifically, at least one of bis(4-hydroxyphenyl)phenylmethane dicaprylate (C ₇ H ₁₅ ), bis(4-hydroxyphenyl)phenylmethane dilaurate (C ₁₁ H ₂₃ ), bis(4-hydroxyphenyl)phenylmethane dimyristate (C ₁₃ H ₂₇ ), bis(4-hydroxyphenyl)phenylethane dimyristate (C ₁₃ H ₂₇ ), bis(4-hydroxyphenyl)phenylmethane dipalmitate (C ₁₅ H ₃₀ ), bis(4-hydroxyphenyl)phenylmethane dibehenate (C ₂₁ H ₄₃ ), bis(4-hydroxyphenyl)phenylethylhexylidene dimyristate (C ₁₃ H ₂₇ ) and the like can be mentioned.

The amount of the discoloration temperature regulator used can be appropriately selected depending on the desired hysteresis width and color density at the time of color development, and is not particularly limited, but it is usually preferable to use it in the range of about 1 to 100 parts by weight per 1 part by weight of the leuco dye.

The thermochromic microencapsulated pigment can be produced by microencapsulating a thermochromic composition containing at least the above leuco dye, developer, and color change temperature regulator so that the average particle size is 0.2 to 3 μm. Examples of microencapsulation methods include interfacial polymerization, interfacial polycondensation, in situ polymerization, liquid curing coating, phase separation from an aqueous solution, phase separation from an organic solvent, melt dispersion cooling, air suspension coating, and spray drying, and can be appropriately selected depending on the application.

For example, in the phase separation method from an aqueous solution, the leuco dye, developer, and discoloration temperature regulator are heated and melted, then added to an emulsifier solution, heated and stirred to disperse them into oil droplets, and then a resin raw material is gradually added as a capsule membrane agent, such as an amino resin solution or an isocyanate resin solution, which is allowed to continue reacting and then the dispersion is filtered to produce the desired thermochromic microcapsule pigment.

The content of these leuco dyes, color developers, and color change temperature regulators varies depending on the type of leuco dyes, color developers, and color change temperature regulators used, the microencapsulation method, etc., but the mass ratio is 0.1 to 100 parts of color developer and 1 to 100 parts of color change temperature regulator per 1 part of the dye. The mass ratio of the capsule membrane agent to the capsule contents is 0.1 to 1.

The thermochromic microcapsule pigment can be set to an appropriate temperature for each color's color development temperature (for example, color development at 0°C or higher) and color loss temperature (for example, color loss at 50°C or higher) by appropriately combining the types and amounts of the above-mentioned leuco dye, color developer, and color change temperature regulator, and it is preferable that the color change from colored to colorless due to heat such as frictional heat.

In the case of thermochromic microcapsule pigments, in order to further improve the line density, storage stability, and writing ability, it is preferable that the wall film is formed of a urethane resin, a urea/urethane resin, an epoxy resin, or an amino resin. Examples of urethane resins include compounds of isocyanate and polyol. Examples of epoxy resins include compounds of epoxy resin and amine. Examples of amino resins include melamine resin, urea resin, and benzoguanamine resin. The thickness of the wall film of the microcapsule color material is appropriately determined depending on the required wall film strength and line density.

The average particle diameter of the thermochromic microencapsulated pigment is preferably 0.2 to 5 μm, and more preferably 0.3 to 3 μm, from the standpoints of colorability, color development, ease of fading, stability, fluidity in the ink, suppression of adverse effects on writing, and compatibility with the photochromic microencapsulated pigment described below. The "average particle diameter" specified here is the value obtained by measuring the average particle diameter (50% diameter) (refractive index 1.8) using a particle size analyzer [Microtrac HRA9320-X100 (manufactured by Nikkiso)].

If the average particle size is less than 0.2 μm, sufficient line density cannot be obtained, while if it exceeds 5 μm, it is undesirable because it deteriorates writing properties, reduces the dispersion stability of the thermochromic microencapsulated pigment, and is prone to ink back caused by vibration. Furthermore, the 90% diameter is 8 μm or less, preferably 6 μm or less. If a certain proportion of particles with large diameters are present, the above-mentioned effects tend to become more pronounced. Note that the microencapsulated pigment that falls within the above-mentioned average particle size range (0.2 to 5 μm) varies depending on the microencapsulation method, but in a phase separation method from an aqueous solution, it can be prepared by appropriately combining the stirring conditions when manufacturing the microencapsulated pigment.

The specific gravity of the thermochromic microencapsulated pigment is in the range of 0.9 to 1.3, preferably 1.0 to 1.2. If the specific gravity is outside this range, the dispersion stability of the microencapsulated pigment is likely to decrease. Furthermore, microencapsulated pigments with a specific gravity exceeding 1.3 are prone to ink back caused by vibration.

In addition to the thermochromic microencapsulated pigment, the aqueous ink composition for writing instruments may contain water (tap water, purified water, distilled water, ion-exchanged water, pure water, etc.) as the solvent as the remainder, and may also contain water-soluble organic solvents, thickeners, lubricants, rust inhibitors, preservatives, or antibacterial agents as appropriate, within the scope of not impairing the effects of the agent, depending on the intended use of the writing instrument (ballpoint pen, marking pen, etc.).

Examples of water-soluble organic solvents that can be used include glycols such as ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, polyethylene glycol, 3-butylene glycol, thiodiethylene glycol, and glycerin, as well as ethylene glycol monomethyl ether and diethylene glycol monomethyl ether, which can be used alone or in combination.

Of these, it is preferable to use glycerin to prevent ink solidification at the writing area due to the ink bag, and the amount added is preferably 1 to 10% by mass of the total amount of ink. The mechanism of action of glycerin is unknown, but it is presumed to have the effect of reducing the cohesive force between the pigment and ink components in a dry state.

As the thickener that can be used, for example, at least one selected from the group consisting of synthetic polymers, cellulose, and polysaccharides is preferable. Specific examples include gum arabic, tragacanth gum, guar gum, locust bean gum, alginic acid, carrageenan, gelatin, xanthan gum, welan gum, succinoglycan, diutan gum, dextran, methylcellulose, ethylcellulose, hydroxyethylcellulose, carboxymethylcellulose, starch glycolic acid and its salts, propylene glycol alginate, polyvinyl alcohol, polyvinylpyrrolidone, polyvinyl methyl ether, polyacrylic acid and its salts, carboxyvinyl polymer, polyethylene oxide, copolymer of vinyl acetate and polyvinylpyrrolidone, crosslinked acrylic acid polymer and its salts, non-crosslinked acrylic acid polymer and its salts, styrene acrylic acid copolymer and its salts, etc.

Of these, it is preferable to use polysaccharides. Due to their rheological properties, polysaccharides tend to be less susceptible to the effects of vibration on fluidity, and are less likely to cause problems such as poor writing caused by ink bag. Xanthan gum is particularly preferable, as it provides an excellent balance with other properties required of writing instrument inks.

Lubricants include fatty acid esters of polyhydric alcohols, which are also used as surface treatment agents for pigments, higher fatty acid esters of sugars, polyoxyalkylene higher fatty acid esters, alkyl phosphate esters, alkyl sulfonates of higher fatty acid amides, alkyl aryl sulfonates, derivatives of polyalkylene glycols, fluorine-based surfactants, polyether-modified silicones, etc. Rust inhibitors include benzotriazole, tolyltriazole, dicyclohexylammonium nitrite, saponins, etc. Preservatives or antibacterial agents include phenol, sodium omadine, sodium benzoate, benzimidazole-based compounds, etc.

This aqueous ink composition for writing instruments can be produced by a conventional method, for example, by blending the thermochromic and photochromic microencapsulated pigments and the other aqueous components in predetermined amounts and stirring and mixing them with a stirrer such as a homomixer or a disperser. If necessary, coarse particles in the ink composition may be removed by filtration or centrifugation.

The viscosity value of the aqueous ink composition for writing instruments is preferably 500 to 2000 mPa·s at 25° C. and a shear rate of 3.83/s, and 20 to 100 mPa·s at a shear rate of 383/s. By setting the viscosity within the above range, an ink having excellent writing properties and stability over time can be obtained. Furthermore, the non-Newtonian viscosity index n calculated by the viscosity formula S=αD ⁿ (where 1>n>0) (S is shear stress (dyn/cm ² ), D is shear rate (s ⁻¹ ), and α is a non-Newtonian viscosity coefficient) is preferably 0.2 to 0.6. By setting the non-Newtonian viscosity index n within the above range in addition to the above viscosity range, it is possible to appropriately set the fluidity of the ink against vibration, and it is possible to prevent the occurrence of ink back.

The surface tension of the aqueous ink composition for writing instruments is preferably 25 to 45 mN/m, and more preferably 30 to 40 mN/m. Within this range, the balance between the wettability of the inside of the pen tip and the ink is appropriate, making it possible to prevent the occurrence of ink back.

In the refill, an ink follower may be placed immediately behind the ink. The material constituting the follower may be composed of at least a non-volatile or low-volatility organic solvent and a thickener. The non-volatile or low-volatility organic solvent used in the ink follower is used as the base oil of the ink follower, and liquid paraffin is used, for example. Mineral oil and chemically synthesized oil are used for the liquid paraffin, and polybutene, poly-α-olefin, ethylene α-olefin oligomer, etc. can be used as the chemically synthesized oil.

Specific examples of mineral oils that can be used include commercially available Diana Process Oil NS-100, PW-32, PW-90, NR-68, and AH-58 (manufactured by Idemitsu Kosan Co., Ltd.).

Specific examples of polybutenes that can be used include commercially available products such as Nissan Polybutene 200N, Polybutene 30N, Polybutene 10N, Polybutene 5N, Polybutene 3N, Polybutene 015N, Polybutene 06N, and Polybutene 0N (all manufactured by Nippon Oil & Fats Corporation), Polybutene HV-15 (manufactured by Nippon Petrochemical Industry Co., Ltd.), and 35R (manufactured by Idemitsu Kosan Co., Ltd.).

Specific examples of poly-α-olefins that can be used include commercially available barrel process oils P-26, P-46, P-56, P-150, P-350, P-1500, P-2200, (P-10000, P-37500) (manufactured by Matsumura Oil Co., Ltd.).

Specific examples of ethylene α-olefin oligomers that can be used include commercially available products such as LUCANT HC-10, HC-20, HC-100, HC-150, (HC-600, HC-2000) (all manufactured by Mitsui Chemicals, Inc.).

These non-volatile or low-volatile organic solvents can be used alone or in combination of two or more.

Examples of thickeners used in the ink follower include calcium salts of phosphate esters, fine silica particles, block copolymers of polystyrene-polyethylene/butylene rubber-polystyrene, block copolymers of polystyrene-polyethylene/propylene rubber-polystyrene, hydrogenated styrene-butadiene rubber, block copolymers of styrene-ethylenebutylene-olefin crystals, block copolymers of olefin crystals-ethylenebutylene-olefin crystals, and acetoalkoxyaluminum dialkylates, and these can be used alone or in combination of two or more.

Preferred commercially available calcium salts of phosphate esters that can be used include Crodax DP-301LA (manufactured by Croda Japan Co., Ltd.). Usable fine particle silica includes hydrophilic fine particle silica and hydrophobic fine particle silica. Preferred commercially available hydrophilic silica products include AEROSIL-300 and AEROSIL-380 (manufactured by Nippon Aerosil Co., Ltd.), and preferred commercially available hydrophobic silica products include AEROSIL-974D and AEROSIL-972 (manufactured by Nippon Aerosil Co., Ltd.).

Preferable commercially available polystyrene-polyethylene/butylene rubber-polystyrene block copolymers include Kraton GFG-1901X and Kraton GG-1650 (both manufactured by Shell Japan), Septon 8007 and Septon 8004 (both manufactured by Kuraray Co., Ltd.), etc. Preferable commercially available polystyrene-polyethylene/propylene rubber-polystyrene block copolymers include Kraton GG-1730 (manufactured by Shell Japan), Septon 2006 and Septon 2063 (both manufactured by Kuraray Co., Ltd.), etc.

Preferred commercially available hydrogenated styrene-butadiene rubber products include DYNARON 1320P, DYNARON 1321P (both manufactured by JSR Corporation), Tuftec H1041, and Tuftec H1141 (both manufactured by Asahi Chemical Industry Co., Ltd.).

Preferred commercially available products of styrene-ethylenebutylene-olefin crystalline block copolymers include DYNARON 4600P (manufactured by JSR Corporation), and preferred commercially available products of olefin crystalline-ethylenebutylene-olefin crystalline block copolymers include DYNARON 6200P and DYNARON 6201B (manufactured by JSR Corporation).

Preferred commercially available acetoalkoxyaluminum dialkylates include PLENACT AL-M (manufactured by Ajinomoto Fine-Techno Co., Ltd.).

Among these thickeners, it is preferable to use thermoplastic olefin-based elastomers such as styrene-ethylenebutylene-olefin crystalline block copolymers and olefin crystalline-ethylenebutylene-olefin crystalline block copolymers.

Furthermore, in order to obtain an ink follower that prevents the occurrence of ink back, it is preferable that the average tan δ value measured for each frequency while exponentially increasing in the frequency range of 1 to 63 rad/s is 1.0 or more, and more preferably 1.7 to 3.4.

Here, tan δ is a value that means the loss modulus/storage modulus, and it has been known in the past that the average tan δ value measured for each frequency while exponentially increasing in the frequency range "1 to 63 rad/s" is preferably 1.0 or less. In the present invention, by making the average tan δ value measured for each frequency in the above 1 to 63 rad/s 1.0 or more, it becomes possible to absorb vibrations and prevent the occurrence of ink back.

Materials that can be used to form the friction body include rubber elastic materials such as thermosetting rubbers such as silicone rubber, nitrile rubber, ethylene propylene rubber, and ethylene propylene diene rubber, thermoplastic elastomers such as styrene-based elastomers, olefin-based elastomers, and polyester-based elastomers, mixtures of two or more rubber elastic materials, and mixtures of rubber elastic materials and synthetic resins. These are configured to form the friction body so that the Taber abrasion amount is less than 15 mg when using the Taber abrasion tester's abrasion wheel H-22 under a load of 9.8 N and 1000 rpm in the abrasion test (ASTM D1044) specified in JIS K7204.

Furthermore, it is preferable that the friction body has a durometer A hardness of 70 or more as specified in JIS K6203. This ensures a predetermined hardness and enables a more stable rubbing action. The friction body can also be used as a touch pen or stylus pen, and may be made conductive.

In addition, by setting the brightness value of the friction body to 70 or less, surface dirt that occurs during use of the friction body can be made less noticeable.

The brightness value is determined by measuring the surface of the friction body using a measuring device such as a general-purpose color difference meter (TC-8600A, manufactured by Tokyo Denshoku Co., Ltd.) using the HLS color space system with a range of 0 to 100.

Figure 15 is a front view of another embodiment in which the clip 105 is connected to the inner tube 104.

Figure 16 is a perspective view of the inner tube 104. The inner tube 104 is similar to the inner tube 4 described with reference to Figures 5 to 7, so only the differences will be described. The inner tube 104 has a front tube portion 41 inserted into the rear barrel 3, a rear tube portion 42 disposed outside the rear barrel 3, and a clip holding portion 143 that holds the clip 105. The clip holding portion 143 of the inner tube 104 has a plurality of recesses 143a formed therein to suppress molding shrinkage during molding by a mold. In addition, a swing restriction portion 143b is formed in the clip holding portion 143 so as to abut against the clip 105 when the clip 105 is operated and to restrict the swing range of the clip 105 when the clip 105 leaves the rear barrel 3. Therefore, as described later, the clip 105 does not have a configuration equivalent to a swing restriction portion, unlike the clip 5 described above.

The clip holding portion 143 is provided with two engagement protrusions 144 that are inserted into the engagement holes 53a of the clip 105. The engagement protrusions 144 have a generally cylindrical shape and protrude from the clip holding portion 143 in a direction perpendicular to the axial direction of the writing instrument 1. The clip 105 is swingably connected to the inner tube 104 via the engagement protrusions 144. The engagement protrusions 144 function as a swing fulcrum when the clip 105 swings. Therefore, the swing restriction portion 143b is provided at least rearward of the engagement protrusions 144 in the axial direction.

The engaging projection 144 has an engaging surface 144a on the outer portion of the end face, i.e., the portion on the clip 105 side. The height of the engaging projection 144 at the engaging surface 144a is lower than the inner portion of the end face of the engaging projection 144. The engaging surfaces 144a of the engaging projections 144 are parallel to each other. The clip holding portion 143 is further provided with two engaging projections 149. The engaging projections 149 have a generally cylindrical shape. The engaging projections 149 protrude from the clip holding portion 143 in a direction perpendicular to the axial direction of the writing instrument 1, and are positioned in front of the corresponding engaging projections 144.

Figure 17 is a perspective view of clip 105. Clip 105 differs from clip 5 described with reference to Figures 9 to 11 only in that it does not have swing restriction portion 51a and spring support portion 51b.

Figure 18 is a front view of the inner tube 104 in a provisionally attached state before the clip 105 is connected to the inner tube 104. When assembling, first provisionally attach the clip 105 to the inner tube 104 (Figure 18). Next, the clip 105 is pressed toward the axial center, causing the engaging protrusions 144 of the inner tube 104 to elastically deform so as to widen the gap between the opposing side wall portions 53. As a result, the engaging protrusions 144 of the inner tube 104 snap into the engaging holes 53a of the clip 105, and the clip 105 is connected to the inner tube 104 (Figure 15).

Temporary fastening will be described with reference to Figures 19 and 20. In Figures 19 and 20, the downward direction is the axial center direction. Figure 19 is a cross-sectional view of the state before the clip 105 is temporarily fastened to the inner tube 104, and is a cross-sectional view similar to Figure 20. Figure 20 is a cross-sectional view taken along line L-L in Figure 18. Temporary fastening is an alignment process before the clip 105 is connected. In other words, temporary fastening means that the temporarily fastened clip 105 is stably attached to the inner tube 104 without tilting, without the aid of external forces such as the hands of the assembly worker, and with a force that will not cause the clip 105 to come off due to its own weight, etc.

The temporary fastening is performed by clamping the mating surface 144a of the engagement protrusion 144 and the end surface of the mating protrusion 149 between the opposing side wall portions 53 of the clip 105 with the restoring force due to the elastic deformation of the side wall portions 53. Therefore, in FIG. 19, which shows the state before temporary fastening, the distance X between the mating surfaces 144a of the engagement protrusions 144 is slightly larger than the distance Y between the opposing side wall portions 53 before temporary fastening at the corresponding positions. In other words, the width of the inner surface of the clip 105 is shorter than the width of the side surface of the clip holding portion 143. For example, it is preferable that the relationship between the distance X between the mating surfaces 144a and the distance Y between the side wall portions 53 is 0.01<X-Y<0.05 mm. Also, in FIG. 20, which shows the state after temporary fastening, the contact length between the mating surface 144a and the side wall portions 53, i.e., the radial length Z, is preferably 0.5 to 3 mm. The temporary fastening may be performed by friction between the surface of the side wall portion 53 and the mating surface 144a of the engagement protrusion 144, and further between the end surface of the mating protrusion 149. The mating protrusion 149 may be omitted.

The temporary fastening can be easily performed by lightly fitting the clip 105 into the clip holding portion 143 of the inner tube 104, particularly the engagement protrusion 144, i.e., by lightly pressing it in, so that the clip 105 can be connected quickly and accurately. As a result, assembly productivity can be improved. In addition, the clip 105 can be connected to the inner tube 104 without damaging the engagement protrusion 144 of the inner tube 104.

The position and shape of the mating surfaces on the engagement protrusions may be arbitrarily adopted as long as the clip is temporarily fastened. Therefore, the two mating surfaces may not be parallel to each other, but may be inclined surfaces that are inclined inwardly and away from each other.

REFERENCE SIGNS LIST 1 Writing implement 2 Front barrel 3 Rear barrel 4 Inner barrel 5 Clip 6 First coil spring 45 Spring retaining portion 45c First protrusion 45d Second protrusion 51 Clip body 51b Spring support portion 52 Protruding portion PL Parting line

Claims (2)

A writing instrument comprising a barrel, a clip pivotably connected to the barrel, and a coil spring disposed between the barrel and the clip and biasing the clip, the coil spring being fitted onto a spring retaining portion provided on at least one of the barrel and the clip,
A writing instrument, characterized in that a spring support part that is arranged in front of the coil spring and supports a front end of the coil spring is provided on the barrel or the clip. A writing instrument comprising a barrel, a clip pivotably connected to the barrel, and a coil spring disposed between the barrel and the clip and biasing the clip, the coil spring being fitted onto a spring retaining portion provided on at least one of the barrel and the clip,
The clip has a protruding portion that protrudes toward the barrel so as to come into contact with the barrel,
A writing instrument, characterized in that a step is provided facing the side opposite to the portion of the protrusion that contacts the barrel in a direction perpendicular to the axial direction of the writing instrument and the protruding direction of the protrusion.

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