JP2005335285A - Pressurizing type writing utensil - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To avoid the fear of staining circumference with the dripping or sucking-out of ink during the unused or carrying state of a utensil by a method wherein no efflux of the ink from a pen point develops. <P>SOLUTION: In the pressurizing type utensil, at a tip of which a pen point is provided while, in an ink housing part at a rear of which, an ink and a follower following up to the ink at the rear end of the ink are provided and, at the rear of the follower, a pumping type pressurizing mechanism is provided, the utensil is so constituted that a no-flowing-out state of the ink from the pen point in the state that the pen point directing downward is in contact with a writing surface develops under the condition that no moving state of the follower to the ink housing part is kept in the state that the rear end of the follower is in keeping with outside air and the follower is movable to the ink housing part together with writing when the rear end of the follower is pressurized not lower than a predetermined pressure. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  In the present invention, a liquid ink is directly filled in the ink containing portion at the rear of the pen tip, and a follower is provided at the rear end of the ink so that the ink can be moved as the ink is consumed. It is related with the writing instrument provided.

JP, 2001-150865, A The pumping type pressurization mechanism part is provided in the rear end of a shaft cylinder, and it is arrange | positioned so that it may contact with the rear end of the ink in front of it, and may track with ink consumption. A valve mechanism is arranged at the rear end of the follower, and air is pushed into the rear end hole of the shaft cylinder by the forward movement of the pressurizing mechanism, and at that time, the valve opens at a predetermined pressure and the rear of the follower There has been proposed one configured to support the fluidity of the ink toward the tip side by pressurizing the end.

  In general, ballpoint pens that use low-viscosity ink or shear-thinning ink have a large ink outflow (in order to increase the writing density). Yes. Further, since the viscosity of the ink is smaller than that of the oil-based ballpoint pen, the flow resistance with respect to the ink containing tube is small. Accordingly, ink leakage (ink flows backward at the rear end of the ink containing tube) is likely to occur due to the weight of the ink, dropping or knocking impact. For this purpose, the ink usually moves following the ink consumption at the time of writing at the trailing edge of the ink, but a grease-like follower that suppresses the back flow of the ink against the ink's own weight or impact is also available. A rod is provided immersed in the follower. However, even if the follower is provided, when writing is performed upward, if the ink on the back surface of the ball of the chip runs out, the ink head is added directly, so that there is a risk of causing a significant back flow and soiling hands and clothes. In addition, since the viscosity of the ink is low and the amount of outflow is large, there is a problem that the ink oozes out (direct current) when a gap is formed between the tip ball and the tip holding portion when the tip side is faced downward.

The writing instrument of the present invention is a writing instrument in which a pen tip such as a ballpoint pen tip, a sign pen, or a marker is used as a pen tip, and an ink containing portion at the back thereof is mainly filled with an aqueous or oily low-viscosity ink. In addition, the ink is prevented from flowing out from the pen tip when the pen tip is in contact with the writing surface, and it is possible to avoid the possibility of the surroundings being soiled by ink dropping or sucking when the writing tool is not used or carried.
In addition, the writing instrument is divided into a pen tip, a front barrel filled with ink, and a rear barrel with a pressurization mechanism to send compressed air by pumping. By combining them as possible, only the front cylinder is made a consumable item, which can be provided to users at low cost.

The present invention has the following configuration in order to achieve the above-described problems.
The pressure-type writing instrument according to the first aspect of the present invention has a pen tip at the tip, an ink storage portion at the rear is provided with ink and a follower that follows the ink at the rear end of the ink, and is further pumped behind it. In a pressure-type writing instrument provided with a pressure mechanism of the type, the rear end of the follower is in equilibrium with the outside air and the follower is maintained in a state where it does not move with respect to the ink containing portion, and the pen tip is moved downward. The ink does not flow out of the pen tip in contact with the writing surface, and the follower can move with respect to the ink containing portion together with writing when the rear end of the follower is pressurized to a predetermined pressure or higher.

  The pressure-type writing instrument according to the invention described in claim 2 is the pressure-type writing instrument according to claim 1, wherein the rear end of the follower is pressurized by air being pumped by the pressurizing mechanism. At the end position of the pumping operation, the rear end of the follower is configured to be able to ventilate with outside air.

  A pressure-type writing instrument according to a third aspect of the present invention is the pressure-type writing instrument according to the first aspect, wherein the joint is provided behind the ink containing portion in which the ink and the trailing end of the ink are filled. A front shaft cylinder provided and a rear shaft cylinder provided with a joint portion in front of a cylinder portion provided with a pumping type pressurizing mechanism, and a rear shaft is provided at the joint portion of the front shaft cylinder. The joining portion of the cylinder is detachably coupled, and the rear end portion of the follower is blocked from outside air.

The pressure-type writing instrument of the present invention is a writing instrument in which a pen tip such as a ballpoint pen tip, a sign pen, or a marker is used as a pen tip, and an ink containing portion at the back thereof is mainly filled with aqueous or oily low-viscosity ink. In addition, ink is prevented from flowing out of the pen tip when the pen tip is in contact with the writing surface downward, and it is possible to avoid the possibility of the surroundings being soiled by dropping or sucking out ink when the writing tool is not used or carried It becomes.
In addition, the writing instrument is divided into a pen tip, a front barrel filled with ink, and a rear barrel with a pressurization mechanism to send compressed air by pumping. Since they can be connected together, it is possible to provide only the front barrel as a consumable and provide it to the user at a low cost.

  FIG. 1 to FIG. 5 show Embodiment 1 of the present invention, and shows a pressure-type writing instrument 1 having a pen point as a ballpoint pen tip. First, the writing instrument 1 includes a front shaft tube 2, a tip 7, a valve body 6, a receiving member 4, an ink 10, a follower 11, a follower rod 12, a rear shaft tube 13, and a pumping type additive provided at the rear end of the rear shaft tube. A cap (not shown) that is configured by a pressure mechanism and is usually fitted to the front shaft portion 3 is provided as the final form of the writing instrument.

  The front shaft cylinder 2 is a resin molded product (usually a transparent resin), and has a tapered front shaft portion 3 integrally formed at the tip, and a joint portion (female screw portion) behind the ink containing portion filled with ink and follower. 2b) is provided. Further, an inner hole 3a is formed from the tip, and there is an expanded hole (becomes the valve chamber 5) at the rear end of the inner hole, and ribs 3c are provided radially at a plurality of locations at the front end of the hole. . In addition, PP resin, a nylon resin molded product, etc. are used for the front shaft cylinder 2 as an example.

On the other hand, the receiving seat member 4 has a tapered or spherical valve body receiving seat 4a on the front surface, and is provided with a guide hole 4d penetrating from the center of the valve body receiving seat 4a to the rear end.
Further, a convex portion 4b is formed in a circumferential shape in front of the outer peripheral portion, and a circumferential or protruding locking portion 4c is formed in the rear.
The receiving member 4 is inserted from the rear end of the front barrel 2 and is positioned in contact with the step portion 2a at the front end of the inner bore of the front barrel, and the convex portion 4b is in close contact with the front bore surface thereof. Further, the locking portion 4c is bitten and locked to the rear inner hole surface.
In addition, it is also possible to provide a groove part and a protrusion between the inner hole surface of the front shaft cylinder 2 and the outer peripheral part of the receiving member 4 and to lock them using elastic deformation.

  Thus, the valve chamber 5 is formed between the front receiving seat 3d serving as the rear end of the rib 3c and the valve body receiving seat 4a serving as the front end of the receiving seat member 4. A spherical valve body 6 is inserted before the receiving seat member 4 is locked, and the valve body 6 is loosely fitted in the valve chamber 5. The valve body 6 is not limited to a spherical shape but may be a rod-shaped piece. In that case, if the groove | channel which can distribute | circulate ink is formed in the front outer periphery of a valve body, it is not necessary to provide said rib 3c in the front end of a valve chamber in particular.

The tip 7 is crimped so that the tip ball 8 is rotatably held in a state where the tip ball 8 is substantially in contact with a seat having a channel through which ink can flow.
Further, a spring 9 is inserted into the tip inner hole 7a, the rear end of the shaft portion 7b behind the tip is properly crimped, and the rear end of the spring 9 is provided so as not to be extracted.
Further, an upright rod shaft portion 9 a is formed at the tip of the spring 9, and the tip of the rod shaft portion 9 a abuts against the back surface of the tip ball 8 in a pressing manner. The tip ball 8 is brought into close contact with the inner edge of the ball holding portion of the chip 7 by the pressing.

It is very important for the tip ball 8 to be in close contact with the inner surface of the ball holding portion for drying the writing tip and preventing direct current of the ink even if the ink has a high viscosity.
In addition, the surface roughness of the inner surface of the chip holding the tip ball 8 as necessary, the inner surface is ground to improve the crimping accuracy, and the secondary plastic processing is performed to increase the crimping accuracy. The In addition, surface treatment or the like is considered on the contact surface with the tip ball if necessary.

The tip 7 is pressure-bonded to the inner hole 3 a at the tip of the front shaft portion 3.
The tip 7 is crimped so that the tip ball 8 is rotatably held in a state where the tip ball 8 is substantially in contact with a seat having a channel through which ink can flow. Further, a spring 9 is inserted into the inner hole portion of the tip 7, and the rear end of the tip shaft portion 7b is appropriately crimped (caulking portion 7c) so that the rear end of the spring 9 cannot be pulled out. In addition, it is possible to provide a pressing member for pressing the back surface of the tip ball 8 on the front surface of the spring, and it is also possible to form the rod shaft portion in an extremely thin coil shape. Furthermore, the tip can be made of a resin molded product with excellent wear resistance and ink sealing performance, and the spring seat that presses the back of the tip ball can be configured as an integral or separate spring seat. is there.

  As described above, when the tip side is facing downward, the valve body 6 abuts against the front receiving seat 3d, and the tip ball from the tip inner hole 7a passes through the groove formed between the guide hole 4d, the valve chamber 5, and the rib. Conducts to the back of 8.

  The front cylinder 2 has an ink containing portion behind the guide hole 4d, and the ink containing portion is filled with low viscosity ink or ink 10 having shear thinning viscosity. Shaped follower 11 is filled. The follower 11 follows the ink as the ink is consumed due to writing when a predetermined pressure or more is applied to the rear end. Further, the follower 11 is incompatible with ink and has a performance of preventing ink evaporation. Moreover, the resin-made follower stick | rod 12 which has specific gravity substantially equivalent to a follower is immersed in a follower as needed. The follower rod 12 can reliably eliminate the cause of the functional failure due to deformation of the grease-like follower when subjected to an impact or the like.

The rear barrel 13 has a knock bar 17 at the rear end, and is provided with a joint portion (male screw portion 13g) in front of a cylinder portion where a pressurizing mechanism is disposed so as to send compressed air by pumping. A seal portion 13h formed as a circumferential convex portion is formed on the front outer peripheral portion. When the rear barrel 13 is coupled to the front barrel 2 by screwing or the like, the seal portion 13h can be in sliding contact with the inner surface of the front barrel to increase the airtight effect.
The pumping type pressurizing mechanism includes a valve mechanism part and a knock mechanism part provided so as to compress a space part formed behind the valve mechanism part.

The valve mechanism is configured as follows.
First, the bush 14 is provided with a hole serving as a valve chamber from the front end in the axial center portion, and a tapered or spherical receiving seat 14b is formed at the rear end of the hole, and a vent hole 14c having a slightly small diameter is formed. Is provided penetrating to the rear end, and a spring is provided between the valve body and the inner step portion 13f provided in front of the inner hole of the rear barrel 13 so that the spherical valve body 15 is in close contact with the receiving seat 14b. 16 is laid, and the bush 14 is tightly fitted into the inner hole of the rear shaft cylinder 13 with the front end in contact with an inner step portion 13e separately provided in front of the inner hole of the shaft cylinder 13, so that the valve mechanism portion is Composed.
As described above, normally, the valve body 15 is in close contact with the receiving seat 14b, the vent hole 14c is closed, and the inner hole of the rear barrel is divided in an airtight manner.

A knock mechanism is disposed behind the valve mechanism.
The knock mechanism is configured as follows.
A tapered slit portion 13c that narrows from the rear end side toward the front side is formed on the side surface of the rear end portion of the rear barrel 13, and a slit portion having a rear step portion 13d at the front end and having a predetermined length in the axial direction forward. 13b is formed.

Further, the knock bar 17 has a hook-shaped knob portion 17b at the rear end and a shaft portion formed in front thereof, and a protrusion 17a and a circumferential groove portion 17c provided at a substantially front end of the shaft portion outer periphery in the middle of the shaft portion outer periphery. As an example, a seal ring 18 made of an elastic body such as rubber or an elastic molding resin is fixed to the groove portion 17c.
The seal ring 18 is selected to have good airtightness and slipperiness. In addition, other lubricants are taken into consideration. Further, the seal ring portion can be integrally formed on the outer periphery of the shaft portion.
Further, a recess 17e having an appropriate depth is formed at the front end of the knock bar 17 from the front end to the rear, a shaft portion 17d is formed at the axial center of the recess 17e, and the front end of the knock rod is further forward of the shaft portion 17d. A convex portion 17f that protrudes further from the surface is formed.

  The knock bar 17 is inserted from the rear end of the rear barrel 13, a knock spring 19 is laid between the rear end of the recess 17e and the rear end of the bush 14, and the protrusion 17a is tapered. The slit portion 13c is elastically expanded, the projection 17a is locked to the front surface of the rear stage portion 13d, and the knock rod 17 is always urged backward by the knock spring 19 with respect to the rear barrel 13. By the way, a ring 13k is fixed to the inner hole of the rear barrel 13 slightly ahead of the front step portion 13j of the slit portion 13c, and the inner diameter of the ring 13k is larger than the inner diameter of the inner peripheral portion 13i of the front rear barrel. The outer periphery of the seal ring 18 is positioned slightly rearward from the rear end of the ring 13k. Therefore, the space 20 formed between the vent 14c and the front end of the knock bar 17 communicates with the outside air.

That is, immediately before the knock rod 17 is moved forward, the space 20 of the rear barrel 13 is communicated with the outside air, and immediately after the knock rod 17 is properly advanced, the outer peripheral portion of the seal ring 18 is in close contact with the inner peripheral portion of the ring 13k. By doing so, it is cut off from the outside air, and is configured to be pressurized as the space portion 20 is reduced.
Further, in a state where the knock bar 17 is advanced and the space portion 20 is appropriately compressed, a convex portion 17f provided at the front end of the knock bar 17 is provided with a valve so that the close contact with the receiving seat 14b of the valve body 15 is released. It contacts the rear end of the body 15.
Note that the ring 13k may be formed integrally with the rear barrel 13 depending on the specifications and assembly convenience.

As described above, the rear end space of the follower 11 is blocked from the outside air by screwing the male screw portion 13g of the rear shaft portion 13 into the female screw portion 2b of the front shaft cylinder 2.
In addition, the joint part which couple | bonds a front axis cylinder and a rear axis cylinder is not restricted to a screw part, but can be achieved also by the elastic engagement of an uneven part.

FIG. 5 is a side view of the slit portion of the rear barrel from the side.
As shown in the figure, the slit portion is provided as a horizontal groove portion 13l via an inclined slit portion 13m along the peripheral surface of the rear barrel 13 from the front step portion 13j of the slit portion 13b. FIG. 5 shows a state in which the knock bar 17 is most advanced and locked to the rear barrel 13 by further rotating operation from the end position of the pumping operation.

6 and 7 show a pressure-type writing instrument 21 which is Embodiment 2 of the present invention.
The second embodiment is a simplified structure of the first embodiment and is basically the same. That is, there is no ink backflow prevention valve mechanism facing the rear end of the tip 7 in the inner hole portion in front of the front barrel 22, and the follower 24 provided at the rear end of the ink 10 has a follower rod. Not soaked. This indicates that Example 1 is perfect for prevention of ink backflow and anti-impact, while Example 2 is substantially free of problems.
In addition, the follower is set so that a predetermined resistance force acts between the ink container and the follower so that the follower can move when a pressure exceeding a predetermined level is applied to the rear end. For example, a filler may be mixed therein, or a fine uneven portion may be provided for applying a frictional force to the inner surface of the ink containing portion.
The follower may be a follower such as silicon rubber.

Moreover, FIG. 8 is a pressure-type writing instrument which is Example 3 of the present invention, and shows only another form of the rear barrel portion.
In this embodiment, a rear shaft portion 26a is provided at the rear of the central flange portion 26c, and a joint 26 in which a female screw portion 26b and a seal portion 26f are integrally formed at the front portion of the flange portion. The rear shaft portion 26a is fitted into the inner hole of the rear shaft cylinder. Further, a receiving seat 26d is formed at the substantially rear end of the inner hole portion formed in the axial center of the joint 26, and a vent hole 26e is provided through the rear end. 28, is pressed against the front end of the spring 28, and the press-fit cylinder 29 is fixed to the inner hole on the front end side of the joint 26, so that a valve chamber is formed between the rear end portion 30 of the press-fit cylinder 29 and the receiving seat 26d. In addition, a through-hole communicating with the valve chamber is provided in the axial center of the press-fitting cylinder 29 to constitute a valve mechanism portion. The knock mechanism is configured in substantially the same manner as in the first embodiment. In addition, the basic configuration of the pumping type pressurizing mechanism constituted by the valve mechanism portion and the knock mechanism portion has been described above, but various forms can be adopted for the valve mechanism portion and the knock mechanism portion depending on the design convenience.

Although the embodiment has been described above, the front shaft cylinder shown in the embodiment 1 and the embodiment 2 in which the tip is filled with the tip and the ink is filled in the back includes the pumping type pressurizing mechanism shown in the embodiment 3. It can be configured in combination with a rear barrel.
Also, in order to prevent the evaporation and drying of ink and follower at the rear end of the front cylinder filled with ink, a seal portion (for example, a film subjected to vapor deposition of aluminum or the like is welded to the rear end surface of the front cylinder or When the rear barrel with the pressurizing mechanism is joined, the seal portion is removed or if it is in the form of a film, it is broken and joined at the front end of the joint portion of the rear barrel Only the front shaft cylinder can be used as a consumable item.

(Function)
Next, the operation of the pumping type pressurizing mechanism will be described below.
If the rear end of the knock bar 17 is pushed forward from the state shown in FIG. 2, the space 20 is exposed to the outside air when the outer periphery of the seal ring 18 comes into close contact with the inner periphery of the ring 13k, as shown in FIG. As the knock bar 17 is further advanced, the outer peripheral portion of the seal ring 18 slides in close contact with the inner peripheral portion of the ring 13k, and the internal pressure increases as the space portion 20 is reduced. Further, in a state where the knock bar 17 is advanced and the space portion 20 is appropriately compressed, a convex portion 17f provided at the front end of the knock bar 17 is provided with a valve so that the close contact with the receiving seat 14b of the valve body 15 is released. The rear end of the follower 11 is pressurized by contacting the rear end of the body 15 and pushing the pressurized air forward of the valve body. The follower 11 can follow the consumption of ink accompanying writing by this pressurizing action. In addition, it prevents the ink from separating from the peripheral surface of the tip ball due to a drop impact, poor ink fluidity, and the like, and prevents the continuous outflow of ink, and recovers when the ink breaks.

Further, a predetermined pressurizing force is set depending on the characteristics of the follower.
In this case, the volume of the space portion 20 when the outer peripheral portion of the seal ring 18 is in close contact with the entire inner peripheral portion of the rear barrel 13 and the convex portion 17 f provided at the front end of the knock rod 17 are the rear end of the valve body 15. It is possible to determine the set value in consideration of the volume of the space when it contacts the surface, or the leak value of the seal portion. In addition, by contacting the rear end of the valve body 15 with the convex portion 17f, a predetermined pressure can be set even if the strength of the spring 16 that presses the valve body 15 varies in a stronger direction than the predetermined strength.

When the knob 17b of the knock bar is rotated in one direction from the above state, the protrusion 17a of the knock bar is guided by the inclined slit 13m and locked to the groove 13l. This state is shown in FIG.
At this time, the seal ring 18 is located in the inner peripheral portion 13i of the rear barrel, and a ventilation path communicating with the outside air is formed from the front of the valve body 15, and the rear end of the follower 11 is maintained in a state of being ventilated with the outside air. Is done.
Therefore, when the writing instrument is not used, the follower does not move even if an external force is applied to the writing tip part carelessly, so that the problem of ink dropping or sucking out can be avoided.

Next, the function of the writing instrument 1 will be described.
First, in a state where writing is not performed, the tip ball 8 is brought into close contact with the inner edge of the chip holding portion by pressing of the spring 9, so that the direct current (leakage) of the ink is ensured even when the rear end of the follower 11 is pressurized. To be prevented. In addition, since the tip ball 8 is slightly retracted by the writing pressure, a gap is formed and the ink flows out, and writing becomes possible.
Even when the spring 9 is not pressed, if the ink viscosity is not too low, the ink filling amount is not too large, or the ink containing portion is not too large, an external force is applied to the tip ball 8. Otherwise, ink leakage can be avoided in practice.
However, in consideration of repeated knock impacts, it is desirable to press with the spring 9 in order to prevent direct current of ink.

The follower bar is used when the ink containing portion has a large diameter.
That is, the grease-like follower has a problem that when the ink containing portion has a large diameter, the grease-like follower is easily deformed due to the influence of an impact or the like. It is possible to increase the rigidity by immersing a resin-made follower rod having a specific gravity substantially equal to that of the follower in the follower.

  Also, the direct current of the ink is fulfilled by pressing the tip ball with a spring, but the ink may flow backwards when the trailing end of the follower is not pressurized, the writing tip is upward, and an impact is applied. There is. In such a case, the tip ball is brought into close contact with the inner edge of the ball holding portion by pressing a spring, and a valve chamber in which the valve body is loosely fitted is provided behind the ball so that the valve body closes the guide hole upward. This can be avoided reliably by providing it side by side. However, the configuration up to that point is unnecessary in actual use.

(Other embodiments)
FIG. 9 shows a pressure-type writing instrument 32 which is another embodiment of the present invention.
In this device, no follower rod is provided in a spring that presses the tip ball into the inner hole of the chip or in a follower provided at the rear end of the ink.
Although it is possible to satisfy this configuration in actual use, it is desirable to provide a spring that presses the tip ball, and this is necessary when used for a refill of a knock type writing instrument that does not seal the tip end of the tip.
Further, the pen tip can be a pen core used for a sign pen, a marker, etc., the pen core is a porous body having continuous pores, a so-called plastic core formed by forming a complicated capillary in the axial direction, It consists of a fiber assembly.
Further, the pumping type pressurizing mechanism described above includes a valve mechanism part and a knock mechanism part provided so as to compress a space part formed behind the valve mechanism part. The pressurizing mechanism can be configured only by a knock mechanism having a pressurizing function.
In this case, the rear end of the follower communicates with the outside air when the knock mechanism is retracted, and is locked so that the forward state is maintained in the advanced state, and the rear end of the follower is brought into a pressurized state.

It is a longitudinal cross-sectional view which shows the principal part of the front cylinder of the writing instrument which is Example 1 of this invention. It is a longitudinal cross-sectional view which shows the rear part and rear-axis part of the front cylinder of the writing instrument which is Example 1. FIG. It is sectional drawing which expanded and showed the operating state of the pressurization mechanism part of the writing instrument which is Example 1. FIG. It is sectional drawing which expanded and showed the state by which pressurization of the writing instrument which is Example 1 was cancelled | released. FIG. 5 is a view showing a state in which the protrusion of the knock bar is locked in the groove of the rear barrel so that the state shown in FIG. 4 is maintained. It is a longitudinal cross-sectional view which shows the principal part of the front cylinder of the writing instrument which is Example 2 of this invention. It is a longitudinal cross-sectional view which shows the rear part and rear-axis part of the front cylinder of the writing instrument which is Example 2. FIG. It is a longitudinal cross-sectional view which shows the rear part and rear shaft part of the front shaft cylinder of the writing instrument which is Example 3. It is a longitudinal cross-sectional view which shows the principal part of the front shaft cylinder of the writing instrument which is another Example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Writing instrument 2 Front shaft cylinder 2a Step part 2b Female screw part 3 Lead shaft part 3a Inner hole 3b Hole part 3c Rib 3d Front receiving seat 4 Receiving member 4a Valve body receiving seat 4b Convex part 4c Locking part 4d Guide hole 5 Valve chamber 6 Valve body 7 Tip 7a Tip inner hole 7b Shaft portion 7c Caulking portion 8 Tip ball 9 Spring 9a Rod shaft portion 10 Ink 11 Follower 12 Follower rod 13 Rear shaft cylinder 13a Step portion 13b Slit portion 13c Tapered slit portion 13d Rear portion 13d 13e Inner step portion 13f Inner step portion 13g Male screw portion 13h Seal portion 13i Inner peripheral portion 13j Front step portion 13k Ring 13l Groove portion 13m Inclined slit portion 14 Bush 14a Rear end portion 14b Receiving seat 14c Ventilation hole 15 Valve body 16 Spring 17 Knock bar 17a Protruding part 17b Knob part 17c Groove part 17d Shaft part 17e Concave part 17f Convex part 18 seal ring 19 knock spring 20 space 21 writing instrument 22 front shaft cylinder 23 front shaft section 24 follower 25 rear shaft cylinder 25a inner peripheral section 25b inner peripheral section 26 joint 26a rear shaft section 26b female screw section 26c collar section 26d receiving seat 26e Vent 26f Seal portion 27 Valve element 28 Spring 29 Press-fit cylinder 30 Rear end portion 31 Knock stick 32 Writing instrument

Claims (3)

A pressure-type writing instrument that has a pen tip at the tip, an ink follower at the rear ink container, a follower that follows the ink at the rear end of the ink, and a pumping pressure mechanism at the rear. In
The writing instrument is maintained in a state where the rear end of the follower is in equilibrium with the outside air and the follower does not move with respect to the ink storage unit, and ink does not flow out of the pen tip with the pen tip contacting the writing surface downward. A pressure-type writing instrument configured to be in a state and configured such that when the rear end of the follower is pressurized to a predetermined pressure or more, the follower can move with respect to the ink containing portion.   The air is fed by the pumping operation of the pressurizing mechanism to pressurize the rear end of the follower, and the rear end of the follower is configured to be able to vent from the outside air at the end position of the pumping operation. Pressurized writing instrument as described in 1. Ink and front end cylinder with ink-filled part filled with follower at the back end of ink and a joint part is provided in front of the cylinder part with pumping type pressurizing mechanism. The rear shaft cylinder is configured to be configured such that a joint portion of the rear shaft cylinder is detachably coupled to a joint portion of the front shaft cylinder, and a rear end portion of the follower is blocked from outside air. The pressure-type writing instrument as described.

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