JP2000198296A - Double writing instrument - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a convenient writing instrument by forming one of mechanical pencil writing elements as a mechanical pencil writing element containing a colored lead except black, and further allowing an eraser to be projectable from or retractable into a rear end of a rear barrel. SOLUTION: When a rear barrel 4 is rotated in another direction to a front barrel 3 or an intermediate barrel 1, a mechanical pencil writing element 7 is retracted, and instead a writing tip of a mechanical pencil writing element 8 is projected from a tip port of the front barrel. When the element is contained, a protrusion 17 becomes unable to be knocked at a position of a narrow groove of a circumferential groove 19. When a top crown 37 is rotated laterally to the front side of the barrel 4, an eraser holder 42 is longitudinally moved, and the eraser 47 is projected from or retracted into a rear end hole 39. One of the writing elements is a mechanical pencil writing element containing a colored lead except black. The colored lead is obtained by impregnating a porous baked core with a dye or pigment ink, and its writing drawing line is easily erasable by the eraser.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention provides a double-type writing instrument in which the tips of a plurality of mechanical pencils are alternately allowed to protrude and retract at a front end of a front shaft, and an eraser is allowed to protrude and retract from the rear end of a rear shaft. About.

[0002]

2. Description of the Related Art As a conventional example, as shown in Japanese Utility Model Application Laid-open No. Sho 60-120889, a writing tip of a pencil and a writing pen such as a ballpoint pen can be selectively protruded and retracted. There are multiple writing instruments that rotate the crown protruding from the rear end so that the eraser can appear and disappear.

The conventional pencil lead has the following disadvantages when used as a colored sharp lead.

(1) A fired pencil lead obtained by kneading, molding, and then firing the mixture, which comprises graphite as a coloring agent, an organic substance, clay or the like as a binder. The pencil lead obtained by this method has recently reached a sufficient practical strength even for a pencil lead, and is known as a pencil lead that can be erased with an eraser. However, there is a drawback that a pencil lead other than black cannot be manufactured due to the colors of graphite and calcined carbon material used.

(2) A non-fired pencil lead obtained by kneading and molding a wax, a binder, a filler, a pigment and the like. According to this production method, various kinds of organic pigments can be used, light resistance and weather resistance are good, and a color pencil lead having a vivid hue can be obtained. However, this colored pencil core is not fired and relies mainly on bonding with an organic binder. Therefore, when it is used as a mechanical pencil lead, sufficient strength cannot be obtained, and since it contains waxes, it cannot be erased with an eraser. There are drawbacks that can not be done.

(3) Water- and oil-repellent substances, binders, body materials,
A non-fired pencil lead obtained by kneading and molding a pigment or the like, and further impregnating the open pores formed around the water / oil repellent substance with oils and fats.
According to this production method, when a liquid oil or the like at room temperature is selected as the oils and fats to be impregnated, it is possible to produce a colored pencil lead that can be easily erased with an eraser to the same extent as in (1) above. However, in the case of using a color pencil lead of a vivid hue using an organic pigment, a binder that can be used is limited to an organic polymer substance or the like due to the heat resistance of the pigment, and thus a fine lead such as for a mechanical pencil is used. In this case, there is a disadvantage that sufficient strength cannot be obtained.

[0007]

SUMMARY OF THE INVENTION According to the present invention, the cylinder is rotated back and forth alternately by rotation of a cylindrical cam with respect to a front shaft or a center shaft.
In a dual-purpose writing instrument that allows the tip of each mechanical pencil to selectively emerge from the tip end of the tip shaft, while maintaining the strength as a fired pencil lead, excellent light resistance, weather resistance,
By using a colored sharp lead for a mechanical pencil obtained based on a method of manufacturing a fired pencil lead that has a vivid color and can be easily erased with an eraser, one of the above-mentioned mechanical pencils is It is a pencil pencil writing body with a built-in colored sharp core other than black, and further, a rear shaft is integrally provided behind the cylindrical cam, and an eraser holder having an eraser sandwiched in the rear shaft is front and rear. It is an object of the present invention to provide a convenient dual-purpose writing instrument which is movably provided and in which an eraser can appear and disappear from the rear end of a rear shaft.

Another object of the present invention is to solve the drawbacks of the conventional wick used in the dual writing instrument of the present invention. It is an object of the present invention to provide a colored sharp core having characteristics such as drawing lines having excellent properties and weather resistance and having erasability by an eraser.

[0009]

Means for Solving the Problems Each of the mechanical pencils is alternately moved back and forth by the rotation of the cylindrical cam with respect to the front shaft or the central shaft, and the tip of the mechanical pencil is selectively protruded from the front end of the front shaft. In addition, the rear shaft is provided integrally behind the cylindrical cam, and an eraser holder with an eraser sandwiched inside the shaft is provided so that it can move back and forth, so that the eraser can come out from the rear end of the rear shaft. In the formed double-type writing instrument, an engagement portion is provided for fitting the front end of the resin-made front shaft and the front end of the resin-made middle shaft in a non-rotatable and non-removable state, and both are fixed and integrated with the center shaft. In each guide groove of the guide part, a return spring is provided between the sliding piece provided at the rear end and the guide part in each guide groove of the respective guide pencils, and it is urged rearward and fitted in the front and rear freely so that the shaft can be moved. Change in direction The cylindrical cam provided with a cam slope that is provided circumferentially at the front end is rotatable with respect to the guide portion or the central shaft, and is prevented from falling off. The tip of each mechanical pencil is alternately moved back and forth by rotation, so that the tip of each pencil penetrates selectively from the tip end of the front shaft. And one of the above-mentioned mechanical pencils is a mechanical pencil with a built-in colored sharp core other than black. It is impregnated with pigment ink, and its writing lines can be easily erased with an eraser.

The following means can be considered as a method for producing a colored sharp core used in the present invention.

(A-1) By kneading, extruding, and firing in a non-oxidizing atmosphere a compounded composition containing at least a constitutional material and an organic excipient, a carbonized material obtained by carbonizing the organic excipient is obtained. Forming a first fired core body as a binder,
The first fired core is heated in an oxidizing atmosphere to remove a carbide binder by oxidation.
A fired core was formed, the pores of the second fired core were impregnated with a perhydropolysilazane-containing liquid, and silicon nitride was generated by heat treatment in an inert atmosphere such as a nitrogen atmosphere or an ammonia gas atmosphere. A high-strength fired pencil lead formed by forming a third fired core having open pores and coloring the third fired core with a coloring agent. (A-2) A fired pencil lead containing, as a colorant, at least a dye or pigment having excellent light resistance and weather resistance in the open pores of a high-strength fired pencil lead having open pores. Note that the above “in an inert atmosphere such as a nitrogen atmosphere” refers to an inert gas atmosphere such as a nitrogen gas atmosphere or an argon gas atmosphere.

[0012]

1 to 4 show a first embodiment of the present invention corresponding to the means for solving the problems. The double-type writing instrument of the present invention comprises a center shaft 1 integrally provided with a guide portion 2, a front shaft 3, a rear shaft 4 integrally provided with a cylindrical cam 5, a pair of sliding pieces 6, 6 ｀, and a pencil pencil writing body 7, 8. ,
The crown 37, the eraser holder 42, and the eraser 47 are main components. First, the center shaft 1 is made of resin, and as shown in FIG. 1, an axially long guide groove 9 opened to the side surface from a substantially central portion to a rear end, and a similar guide groove 9 ｀ on the opposite side surface.
Is provided. The front half of the guide portion 2 is provided with a cylindrical portion 10 having a partition portion 16 having holes 32, 32 ° communicating with the guide grooves 9, 9 ° and having an open front end, and a rear end of the cylindrical portion 10. The step 31
A bulging engagement portion 13 is formed on the outer peripheral portion of the front side.

As shown in FIG. 2, a vertical groove 18 is formed on the rear side surface of the center shaft 1 through a narrow surface 18a through an inclined surface 18a.
Are connected to the circumferential groove 19 to form a substantially gate-shaped window. As will be described later, the projection 17 of the cylindrical cam 5 is
The projection 17 elastically expands the inclined surface 18a, passes through the narrow portion 51, and enters the circumferential groove 19. The cylindrical cam 5 rotates while the projection 17 abuts on the rear wall of the circumferential groove 19 in the circumferential direction, so that the writing portion of the mechanical pencil 7 or the mechanical pencil 8 alternately emerges from the front end of the front shaft. Become. Also, the circumferential groove 19 is made of the mechanical pencil 7
And projection 1 when mechanical pencil 8 protrudes
7 so that the cylindrical cam 5 can move axially at the position 7.
a and 50c are provided, and a narrow groove 50b is provided between the rear wall 48 and the front wall of the circumferential groove 19 so that the cylindrical cam 5 cannot move substantially at the position of the projection 17 when the cursive writing is stored. A front wall 49b protruding rearward is formed to be formed.

The tip shaft 3 is tapered at the front, has an inner step 27 at the tip of the inner hole, and is provided with a tip opening. In the rear end hole, an engagement groove 12 is provided, which engages with an engagement portion 13 provided on the outer peripheral portion of the cylindrical portion 10 of the guide cylinder, and prevents the cylindrical portion 10 from slipping out and rotating. . The cylindrical portion 10 and the front shaft 3 are detachably fixed by an appropriate force. (Showa 6
(Same as the configuration of the front shaft in JP-A-4-3491)

The rear shaft 4 is made of resin and has a cylindrical cam 5 integrally at the tip. The cylindrical cam 5 has a cylindrical shape, and has a cam slope 14 that is circumferentially displaced back and forth at the front end edge.
A cutout 15 is formed at the foremost end of the fourth member 4. On the side surface of the cylindrical cam 5, there is formed a projection 17 which is inserted into the vertical groove 18 of the center shaft 1, elastically fits into the circumferential groove 19, and rotates and prevents it from falling out within a certain range (approximately 180 degrees). .

The rear shaft 4 has a cylindrical portion extending behind the cylindrical cam 5, and a spiral groove 33 is formed in an inner hole of the cylindrical portion. A rear end of the cylindrical cam 5 has a boss portion 36 which protrudes slightly in a circumferential shape, and a shaft portion 34 having a protruding engagement portion 35 is provided at the rear of the cylindrical portion. On the other hand, the crown 37 made of resin is an inner cylindrical portion 40 having a long slit 41.
b and an outer cylindrical portion 40a formed with an engaging portion 38 having a circumferential groove on the inner surface on the outside thereof. The crown 37 has an inner cylindrical portion 40b fitted into an inner hole of the rear shaft 4, and an engaging portion 38 of the outer cylindrical portion 40a elastically fits into the engaging portion 35. At 40a, the cap 4 is fixed so as to be rotatable only. The boss 36 serves as a guide for the tip of the inner cylinder 40b.

Further, an eraser 4 is provided at the rear end in the inner cylindrical portion 40b.
7 is attached. The eraser holder 42 is formed with a pair of elastic pieces 45 for sandwiching the eraser 47 at the rear, and has an engaging projection 46 on the inner surface of the elastic piece 45. A projection 44 is formed on the outer periphery of the front cylindrical portion 43. The eraser holder 42 has the projection 44 and the elastic piece 45 fitted in the slit 41 of the inner cylinder, and the projection 44 is further fitted in the spiral groove 33 so that the inner cylinder 40 b
It is arranged in. In this state, when the outer cylindrical portion 40 a is rotated with respect to the rear shaft 4, the eraser holder 42 moves back and forth, so that the eraser 47 can protrude and retract from the rear end hole 39.

The sliding piece 6 has a projection 22 on the outer surface, a central portion protruding from the rear end surface of the projection 22, and both sides thereof have substantially the same gradient as the cam slope 14 of the cylindrical cam 5 described above. It has a slope. Further, a hole is provided which abuts against the flange portion 24 of the core pipe 23 to protrude and fit the rear of the core pipe 23 long. The sliding piece 6 # has a projection 22 # and a cam slope like the sliding piece 6. Mechanical pencils 7, 8 are fitted to the tips of the core pipes 23, 26 penetrating the sliding pieces 6, 6 #.

The mechanical pencil 7 has a built-in general chuck mechanism, is joined to the core pipe 23 via a joint 29 connected to the chuck mechanism at the rear end, and has a flange portion 24 provided behind the core pipe 23. The sliding piece 6 is fitted in contact with the sliding piece 6, and the rear end hole of the core pipe 23 protruding from the rear end of the sliding piece 6 is closed by a tail plug 25 or the like. The leading of the lead is performed by moving the chuck by the axial movement of the sliding piece 6 in a state where the step 28 at the tip end of the mechanical pencil 7 is in contact with the inner step 27 of the front shaft 3. Note that the mechanical pencil 8 is similarly formed.

Next, the assembling sequence will be described. The mechanical pencils 7 and 8 are connected with the sliding pieces 6 and 6 # at the rear, respectively, so that the guide grooves 9 and 9 of the guide portion 2 of the center shaft described above.
リ タ ー ン, and are urged rearward by return springs 30, 30 介 interposed between the front end faces of the sliding pieces 6, 6 と and the guide grooves 9, 9 仕 the front partition part 16. Is done. The rear shaft 4 is formed by inserting the cylindrical cam 5 into the rear end hole of the center shaft 1 so that the protrusion 17 is elastically fitted into the circumferential groove 19, and is rotatable at substantially 180 degrees in the circumferential direction with respect to the center shaft 1 and is prevented from falling. And is stopped. The rear shaft 4 can be shifted by the stroke required for centering the center shaft 1 with respect to the center shaft 1 in a state where the mechanical pencils 7 and 8 protrude. Further, since the sliding pieces 6, 6 # are always urged rearward by the return springs 30, 30 #, the cam slopes of the projections 22, 22 # always contact the cam slope 14 of the cylindrical cam 5. Is kept.

The engaging portion 13 of the cylindrical portion 10 is elastically fitted in the engaging groove 12 of the front shaft 3 with the rear end surface of the front shaft 3 in contact with the front surface of the step portion 31 of the center shaft 1. As a result, the front shaft 3 and the center shaft 1 are fixed in a state where they are stopped from rotating and come off. The tip shaft 3 is detachable with an appropriate force. In this state, when the rear shaft 4 is rotated in one direction with respect to the front shaft 3 or the center shaft 1, the sliding piece 6 advances, and the notch 15 at the foremost end of the cam slope 14 of the cylindrical cam is turned into one of the mechanical pencils 7. Projection 2 of sliding piece 6
2 and the writing tip projects from the tip of the front shaft. When the rear shaft 4 is rotated with respect to the front shaft 3 or the center shaft 1 in the other direction, the sliding piece 6 is retracted so that the writing tip of the pencil pencil writing body 7 is immersed from the tip of the front shaft and the sliding piece is moved. 6 ° moves forward, and the writing tip of the other mechanical pencil writing body 8 projects from the tip end of the front shaft.

On the other hand, the eraser holder 42 with the eraser 47 fixed thereto is inserted into the inner cylindrical portion 40b of the crown 37 while rotating from the rear end of the cap 4 while being fitted into the inner cylindrical portion 40b of the crown 37. 40a is fixed to the rear end of the cap 4. As described above, when the outer cylindrical portion 40 a of the crown is rotated right and left with respect to the rear shaft 4, the eraser 47 appears and disappears from the rear end hole 39.

FIGS. 3 and 4 show another example of the engagement between the projection 17 of the cylindrical cam and the central shaft 1 °. In this case, as means for fitting the projection 17 into the circumferential groove 60,
A partition wall 62 having an inclined surface 63 is provided on an upper wall of a guide groove 61 in which the projection 17 is fitted from the rear end of the central shaft 1 #.
The reason for providing the partition wall 62 is to enhance the rigidity of the center shaft 1 ° at the engaging portion.

In the embodiment, two mechanical pencils are provided, but three or more mechanical pencils can be provided. In that case, it is also possible to use one as a writing body such as a ballpoint pen. Also, there are various means for fixing the cylindrical cam to the center shaft so as to prevent the cam from coming off and to rotate. Further, although the guide portion of the sliding piece is formed integrally with the center shaft, a separate guide portion may be fixed. Further, although the rear end of the core pipe projects through the sliding piece to the rear of the sliding piece, the rear of the sliding piece may be provided to protrude long.

FIG. 5 shows a second embodiment of the present invention corresponding to the means for solving the problem. The double-type writing instrument of this embodiment has the same components as those of the above-described embodiment, and only the differences will be described below. The rear shaft 70 is made of resin and integrally has a cylindrical cam 71 at the tip. The cylindrical cam 71 has a cylindrical shape, has a cam slope that is circumferentially displaced back and forth at the front end edge, and a notch is formed at the foremost end of the cam slope.
The rear shaft 4 has a cylindrical portion 7 extending behind the cylindrical cam 71.
2, a slit 73 is formed in a side surface of the cylindrical portion 72, and protrusions 74 and grooves 75 are provided alternately on both sides of the slit 73.

Further, an eraser holder 79 having an eraser 84 fixed to the rear end thereof is mounted in the cylindrical portion so that an engaging projection 82 provided on the outer periphery thereof is removably fitted into the groove 75 of the slit 73. . The engaging projection 82 is formed at the tip of an elastic piece 80 provided on the side surface of the eraser holder 79, and engages with the groove 75 while elastically displacing the groove 75 along with sliding.
Is kept in the protruding state. Further, the center of the engaging projection 82 is slightly protruded to form the operating projection 81, and the eraser holder 79 can be moved while moving the operating projection 81 back and forth to release the engagement between the engaging projection 82 and the groove 75. And A crown 77 is fixed to the rear end of the cylindrical portion. If necessary, the rear end portion 76 of the cylindrical portion and the contact portion 78 of the crown 77 form a slope so that they are substantially in contact with each other, so that deformation of the rear end of the slit 73 is suppressed.

On the other hand, the order of assembly will be described.
Insert the eraser holder 79 from the rear end of the cylinder part 0,
The engaging projection 82 of the eraser holder 79 is engaged with the groove 75 of the slit 73 provided in the cylindrical portion to make the eraser holder 79
Is slidable with respect to the cylindrical portion. The crown 77 is fixed to the rear end of the cylindrical portion, and the eraser 84 is inserted from the opening at the rear end of the crown 77, and the rear end of the eraser 84 is fixed to the eraser holder 79. As described above, when the eraser holder 79 is moved back and forth, the eraser 84 comes out of the opening of the crown 77. Note that the inner diameter of the opening of the crown 77 is slightly larger than the outer diameter of the eraser 84.

In addition, as a method for producing a colored sharp core used in the compound writing instrument of the present invention, a perhydropolysilazane-containing liquid is impregnated into pores of at least a specific fired porous core made of a body material, and a nitrogen atmosphere or the like is used. It has been found that the problem can be solved by generating silicon nitride as a binder by heat treatment in an inert atmosphere or an ammonia gas atmosphere.

That is, the colored sharp core is carbonized by kneading, extruding, and firing in a non-oxidizing atmosphere a compounding composition containing at least a body material and an organic excipient. 1
Forming a fired core, heating the first fired core in an oxidizing atmosphere to form a second fired core made of at least a constitutional material obtained by oxidizing and removing a carbide binder; In the pores, impregnated with a liquid containing perhydropolysilazane,
Forming a third fired core in which silicon nitride is formed by heat treatment in an inert atmosphere such as a nitrogen atmosphere or an ammonia gas atmosphere, and forming the third fired core with a colorant having excellent light resistance and weather resistance; It is a colored high strength fired sharp core. or,
A high-strength fired sharp core characterized in that pores of the third fired core are filled with a coloring agent having excellent light resistance and weather resistance.

Hereinafter, the colored sharp core of high-strength firing used in the present invention will be described in detail. First, the first fired core is made from a blended composition containing at least a body material and an organic excipient.

The extender is not particularly limited as long as it is conventionally used for a fired color pencil, and any of them can be used. For example, a white base material such as titanium oxide, mica, talc, boron nitride, silica, alumina, or calcium carbonate, or a colored base material such as molybdenum disulfide or tungsten disulfide depending on the hue can be used. Of course, mixtures of these several types can also be used. Moreover, you may mix | blend a heat resistant pigment as needed.

Examples of the organic excipient include thermoplastic resins such as vinyl chloride resin, chlorinated vinyl chloride resin and polyvinyl alcohol, thermosetting resins such as furan resin, phenol resin and epoxy resin, lignin, and the like. Cellulose, natural polymer substances such as tragacanth gum, petroleum asphalt, coal tar pitch, naphtha cracked pitch,
Any pitch, such as carbonized pitch, such as synthetic resin, can be used. Naturally, a mixture of several types of these can also be used.

Furthermore, water, dioctyl phthalate (DOP), dibutyl phthalate (DB) are used for the purpose of improving the characteristics at the time of kneading by applying a high shear force and the characteristics of extrusion molding.
P), one or more plasticizers or solvents for organic excipients such as tricresyl phosphate (TCP), dioctyl adipate (DOA), propylene carbonate, alcohols, ketones, and esters. You may mix according to it.

After thoroughly kneading these compounded compositions with a Henschel mixer, a pressure kneader, a two-roller or the like, they are extruded into a fine wire or the like by an extruder, and then inertized in a nitrogen atmosphere or an inert gas such as argon gas. By firing in a non-oxidizing atmosphere such as a gas atmosphere, a first fired core body using a carbide obtained by carbonizing an organic excipient as a binder is obtained. The obtained first fired core body is a core body in which pores and carbide binders generated by firing are fine and sufficiently present, are uniformly dispersed, and the orientation material is highly oriented.

In order to increase the strength of the second fired core and improve the handleability, if necessary, the compounded composition for obtaining the first fired core may contain an inorganic material such as bentonite or kaolin. A binder may be blended, and when the blending amount is less than 25% by weight, the strength of silicon nitride described later is easily developed. If necessary, the first fired core obtained above was impregnated with a liquid containing perhydropolysilazane, and silicon nitride was formed by heat treatment in an inert atmosphere such as a nitrogen atmosphere or an ammonia gas atmosphere. It may be a fired core.

The first fired core obtained above is heated in an oxidizing atmosphere to oxidize and remove the carbide binder, whereby a second fired core comprising a porous core having a large number of pores is obtained. . Here, the pores of the second calcined core are formed by calcining a kneaded material composed of a constitutional material and an organic excipient in a non-oxidizing atmosphere, and removing the binder of the carbide. From the pores obtained by the above method. Adjustment of the porosity of the second calcined core is mainly performed by adjusting the blending ratio of the organic excipient, but it is also possible to appropriately add a pore forming material such as a carbon particulate material in addition to the above. I don't care. The amount of pores by removing the binder of the carbide with respect to all the pores is completely arbitrary.

As described above, the obtained second fired core is a porous core having a large number of pores, and the pores are fine and sufficiently present, and are uniformly dispersed. It is a core body in which the material is highly oriented. Thereby, the second fired core obtained from the first fired core is useful for obtaining the desired high-strength fired colored sharp core.

The third fired core is obtained by impregnating the second fired core made of the porous core obtained above with a perhydropolysilazane-containing liquid, and then impregnating the second fired core with the perhydropolysilazane-containing liquid. (2) Obtained by producing silicon nitride as a binder in the second fired core by heat-treating the fired core in an inert atmosphere such as a nitrogen atmosphere or an ammonia gas atmosphere at 400 ° C. or higher, preferably 600 ° C. or higher. .

The larger the filling amount of the perhydropolysilazane-containing liquid in the second fired core, that is, the higher the porosity of the second fired core, the greater the amount of silicon nitride produced as a binder, resulting in a higher yield. The mechanical strength of the resulting third fired core becomes strong. However, if the porosity of the second fired core exceeds 80%, the shape of the core is difficult to maintain, and the impregnation step with the liquid containing perhydropolysilazane becomes difficult. If the porosity is less than 30%, the amount of the perhydropolysilazane-containing liquid is small, and a remarkable improvement in mechanical strength cannot be expected.
Further, if the porosity is less than 30%, the amount of ink to be filled in the obtained third fired core body is small, and practical coloring and density cannot be obtained, which is not preferable. Therefore, the range of the porosity of the second fired core is 30 to 80%, but in order to improve the quality of the obtained third fired core, it is preferably 35 to 75%. preferable.

The perhydropolysilazane used to obtain the third fired core is a ceramic precursor polymer, has a [-Si-N-] structure in the main chain, and has only hydrogen bonded to a side chain. In the general formula, [SiHaN
b] n (where a is 1 to 3, b is 0 or 1),
The structure mainly has a skeleton of [-SiH2 NH-] n. Further, only hydrogen is erased by thermal decomposition in an inert atmosphere such as a nitrogen atmosphere or an ammonia gas atmosphere, and silicon nitride as a binder can be obtained in a very high yield. The generated silicon nitride is mostly trisilicon tetranitride [Si3 N4], but may be present in a slightly different form [Six Ny] depending on the raw materials used, heat treatment conditions and the like.

Further, since it does not contain an organic component such as a methyl group, a colorless, transparent and high-purity silicon nitride containing no carbon can be obtained. Further, the obtained silicon nitride has a lower temperature than other sintering methods, that is, the sintering method obtained from silicon powder is 1200 ° C.
Although the treatment is performed at a high temperature of 1400 ° C., this method is characterized in that it can be obtained at a low temperature of about 600 ° C. in an inert atmosphere such as a nitrogen atmosphere or an ammonia gas atmosphere. The perhydropolysilazane-containing liquid used in this method is a solution obtained by dissolving the above-mentioned perhydropolysilazane with an organic solvent. If the perhydropolysilazane-containing liquid is capable of impregnating the second fired core, the organic solvent to be used is used. Is not particularly limited, and any of them can be used. Examples of the organic solvent to be used include organic solvents such as benzene, toluene, xylene, tetrahydrofuran (THF), methylene chloride, carbon tetrachloride, and aromatic hydrocarbons.

As a method for impregnating the second fired core with the perhydropolysilazane-containing liquid, the second fired core is immersed in the perhydropolysilazane-containing liquid and, if necessary, heated, depressurized, pressurized or the like. This can be done by impregnating underneath. Here, the impregnation state of the perhydropolysilazane-containing liquid impregnates and impregnates finely and uniformly in the second fired core. That is, as described above, the second fired core body has fine pores which are sufficiently present and are uniformly dispersed, the body material is highly oriented, and a high-strength fired colored sharp core body is obtained. Is useful for
The perhydropolysilazane-containing liquid is finely and uniformly dispersed and impregnated in the second fired core. In addition, in order to obtain a high-strength third fired core, if necessary, the impregnation with the liquid containing perhydropolysilazane and the firing step may be repeated.

In the obtained third fired core, silicon nitride as a binder is finely and uniformly dispersed in the core, and a small amount of nitride is formed because the base material is highly oriented. The production of silicon makes it easy to develop the strength of the core, and the collapse of the core during writing becomes uniform.

The high-strength fired colored sharp core is obtained by filling the pores of the third fired core obtained above with a coloring agent having excellent light resistance and weather resistance. As a coloring agent to be filled, a dye having excellent light resistance and weather resistance is added to water,
It can be dissolved in an organic solvent or the like to form an ink and further impregnated. Further, when light resistance and weather resistance are required, the use of a pigment is conceivable.However, it is not possible to color the inside of the core simply with a dispersion of water, an organic solvent, or the like. A method of impregnating an organic pigment dissolved in an organic solvent or the like, further solidifying the pigment by means such as water precipitation in open pores, impregnating a liquid containing a pigment precursor into the open pores of the core, and further opening The pigment can be filled into the core by a method of causing a pigmentation reaction in the pores, a method of impregnating the open pores of the core with a dye solution or a precipitant solution, and causing a rake reaction in the open pores to form a pigment.

In any of the above-mentioned coloring agent filling methods, in order to promote the impregnation, it is possible to carry out the impregnation under heating, reduced pressure and pressure, or to carry out the impregnation in the presence of a surfactant or other additives. It is. Further, it is possible to make the color tone deeper by repeatedly filling, and it is also possible to color by two different filling methods.

Further, it is possible to improve the lubricity at the time of writing by impregnating extra open pores with oil or the like. In order to be able to erase as much as a fired black core (black core) with an eraser, it is necessary to select from oils and fats and / or waxes which are liquid at normal temperature. Specific examples include silicone oil, mineral oil, liquid paraffin, and α-olefin oligomer.

[0047]

In the first embodiment, when the rear shaft 4 is rotated in one direction with respect to the front shaft 3 or the center shaft 1, the notch provided at the tip of the cam slope 14 of the cylindrical cam 5 as shown in FIG. Reference numeral 15 engages with the sliding piece 6 of one mechanical pencil writing body 7 to protrude the writing tip from the tip end of the front shaft. At this time, the projection 17 of the cylindrical cam 5 is located in the wide groove 50a in the circumferential groove 19 of the center shaft 1. In this state, when the rear end of the crown 37 is knocked and the cylindrical cam 5 is axially moved, the operation is transmitted to the sliding piece 6, the core pipe 23, and the mechanical pencil 7, and the step 28 of the writing tip is moved. From a state in which the chuck comes into contact with the inner step portion 27 of the front shaft 3, the chuck moves along with the joint 29 so that the core is extended. When the rear shaft 4 is rotated to the other side with respect to the front shaft 3 or the center shaft 1, the mechanical pencil writing body 7 retreats, and the writing tip of the mechanical pencil writing body 8 protrudes from the front shaft tip opening instead. In addition, when the cursive writing is stored, the protrusion 1
7 is located in the narrow groove 50b of the circumferential groove 19, and knocking is impossible. Next, when the crown 37 is rotated left and right with respect to the front of the rear shaft 4, the eraser holder 42 moves back and forth, and the eraser 47 projects from the rear end hole 39.

In the second embodiment, when the rear shaft 70 is rotated in one direction with respect to the front shaft 3 or the center shaft 1, the notch provided at the tip of the cam slope of the cylindrical cam 71 as shown in FIG. Engages with the sliding piece of one of the writing pencils 7 to protrude its writing tip from the tip end of the front shaft. In this state, when the rear end of the crown 77 is knocked and the cylindrical cam is axially pushed, the operation is as follows: sliding top, core pipe, mechanical pencil 7
Is transferred to the inner end 2 of the front shaft 3.
From the state in which the chuck comes into contact with 7, the chuck moves along with the joint so that the core is extended. Further, when the rear shaft 70 is rotated with respect to the front shaft 3 or the center shaft 1 in the other direction, the mechanical pencil writing body 7 retreats, and instead, the writing tip of the mechanical pencil writing body 8 protrudes from the front shaft tip opening.

Next, when the operation projection 81 of the eraser holder 79 is pressed and retracted with respect to the rear shaft 70, the engagement projection 82
Is moved away from the groove 75 of the slit 73, the eraser holder 79 is gradually retracted, and the eraser 84 is fed out from the opening of the crown 77. Also, the operation protrusion 81
Is pushed forward, the eraser holder 79 moves forward, and at the same time, the eraser 84 enters through the opening of the crown 77.

[0050]

As described above, the present invention is a double-type writing instrument comprising a plurality of writing element tips that can selectively emerge from a tip end of a front shaft and an eraser that can appear and retract at a rear end thereof. Of the mechanical pencils, one is a mechanical pencil with a built-in colored sharp core other than black.
The colored sharp core is made of a core that can be easily erased with an eraser, and the colored sharp core used is a fired porous pencil core that solves the drawbacks of the conventional core, and keeps the strength strong. In addition, it has the characteristics of having bright colors, drawing light lines with excellent light resistance and weather resistance, and having the erasability by an eraser, and has excellent portability.
It is an object of the present invention to provide a convenient double-type writing instrument that is easy to write and erase and that can be equipped with an erasable color core other than black.

Specifically, it has two mechanical pencils, a W pen having a black sharp core and a red sharp core, and three mechanical pencils, respectively.
Convenient double writing implements can be provided according to the choice of use such as triple pens with black sharp core, red sharp core, blue sharp core, etc., triple pens with two mechanical pencils and ballpoint pens. Becomes

[Brief description of the drawings]

FIG. 1 is an overall longitudinal sectional view showing a first embodiment of the present invention, and is partially not shown in section.

FIG. 2 is an explanatory diagram showing an engagement state between a projection of a cylindrical cam and a peripheral groove of a center shaft.

FIG. 3 is an explanatory view showing another example of an engagement state between a projection of a cylindrical cam and a peripheral groove of a center shaft.

FIG. 4 is a cross-sectional view of a main part of an engaging portion in FIG. 3;

FIG. 5 is an overall vertical sectional view showing a second embodiment of the present invention, and is partially non-sectional view.

[Explanation of symbols]

 Reference Signs List 1 center shaft 1１ center shaft 2 guide portion 3 front shaft 4 rear shaft 5 cylindrical cam 6 sliding piece 6 カ ム sliding piece 7 mechanical pencil writing body 8 mechanical pencil writing body 9 guide groove 9 guide groove 10 cylinder part 11 knock spring 12 Engagement groove 13 Engagement part 14 Cam slope 15 Notch 16 Partition part 17 Projection 18 Vertical groove 18a Inclined surface 18b Narrow part 19 Peripheral groove 20 Wall 21 Window 22 Projection 22 ｀ Projection 23 Core pipe 24 Flange part 25 Tail plug 26 Core Pipe 27 Inner Step 28 Step 29 Joint 30 Return Spring 30 ｀ Return Spring 31 Step 32 Hole 32 ｀ Hole 33 Spiral Groove 34 Shaft 35 Engagement Part 36 Boss 37 Top Crown 38 Engagement Part 39 Rear End Hole 40a Outer tube part 40b Inner tube part 41 Slit 42 Eraser holder 43 Tube part 44 Projection 45 Elastic piece 46 Locking projection 47 Eraser 48 Rear wall 49a Front wall 49b Front wall 49c Front wall 50a Wide groove 50b Narrow groove 50c Wide groove 60 Peripheral groove 61 Guide groove 62 Partition wall 63 Inclined surface 70 Rear shaft 71 Cylindrical cam 72 Cylindrical part 73 Slit 74 Projection 75 Groove 76 Rear end 77 Crown 78 Contact part 79 Eraser rubber holder 80 Elastic piece 81 Operation projection 82 Engagement projection 83 Fitting part 84 Eraser

Claims (1)

[Claims] The present invention is characterized in that each pencil writing body is alternately moved back and forth by rotation of a cylindrical cam with respect to a front axis or a center axis, so that the tip of the mechanical pencil writing body can be selectively protruded and retracted from a front end of a front axis. , A rear shaft is integrally provided behind the cylindrical cam, and an eraser holder with an eraser sandwiched inside the shaft is provided so as to be able to move back and forth, so that the eraser can come out from the rear end of the rear shaft. In the writing instrument, an engagement portion is provided for fitting the front end of the resin-made shaft and the front end of the resin-made middle shaft in a non-rotatable and non-removable state, and both are fixed, and each of the guide portions integrated with the middle shaft is provided. A return spring is provided between the guide piece and the sliding piece provided at the rear end of each mechanical pencil in the guide groove, and is urged rearward and fitted in the guide groove so as to be movable back and forth, and is displaced in the axial direction. Cam slope A cylindrical cam provided circumferentially at the front end is rotatable with respect to the guide portion or the central shaft and is prevented from falling off, and each sliding piece is brought into contact with the cam slope to alternately rotate the cylindrical cam with respect to the front shaft or the central shaft. By moving it back and forth, the tip of each mechanical pencil writing material is selectively made to protrude and retract from the tip end of the front shaft, and when the mechanical pencil is protruded, the cylindrical cam is axially shifted with respect to the center shaft and the guide part and the core is extended. In addition, one of the above-mentioned mechanical pencils is a mechanical pencil with a built-in colored sharp core other than black, and the colored sharp core is a porous fired core with a dye or pigment ink. A double-type writing implement characterized by being impregnated with, and whose writing lines can be easily erased with an eraser.