JP2008120033A - Pressurizing-type writing utensil - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a pressurizing-type writing utensil of such a design that a barrel diameter can be reduced and the pressurizing effect can be diminished following the discharging of a writing fluid. <P>SOLUTION: This pressurizing-type writing utensil is configured as follows: an annular recess 41 is formed on the outer peripheral surface of a piston member 40 inside a barrel 10, and an annular airtight member 42 for the piston member 40 is arranged inside the annular recess 41 so as to allow the piston member 40 to move in the axial direction. Further, a first vent channel 40b1, which makes the annular recess 41 communicate with the outside of the barrel 10, is arranged to the centrifugal side rather than to an airtight contact part 41a which comes into contact with the annular airtight member 42 for the piston member 40 at the inner rear end of the annular recess 41. Also, a second vent channel 40b2 which makes the annular recess 41 communicate with a pressurizing space part S1, is arranged to the centripetal side rather than to the airtight contact part 41a. Besides, the pressurizing space part S1 of the refill 20 backward side can be pressurized and released by the reciprocation of the piston member 40 and the movement of the airtight member 42 inside the annular recess 41. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a pressure-type writing instrument in which a flow rate of writing liquid discharged from a writing unit by forced pressurization is maintained at an appropriate level, and particularly to a pressure-type writing instrument suitable as a correction pen.

  Conventionally, as described in Patent Document 1, for example, this type of writing instrument includes a substantially tubular refill (2) filled with a writing liquid (ink i) in a shaft tube (1), and the refill ( 2) A holder (3) provided so as to cover the rear end side, and a cylinder (N4) which forms a pressure space portion on the rear side of the holder (3) so as to cover the holder (3) And pressurizing and depressurizing the pressurizing space by advancing and retracting the cylinder (N4) by an external operation.

  However, according to the above prior art, since the holder (3) and the cylinder (N4) are superposed in the radial direction on the rear end side of the refill (2), the outer diameter of the structure becomes relatively large. As a result, there has been a problem that the shaft diameter of the shaft cylinder for housing the structure becomes large.

  As another conventional technique, for example, as described in Patent Document 2, a pressure pumping mechanism (30) is inserted into a rear end opening of a refill (ink filling tube 21), and these refill and pressure pumping are inserted. There is a writing instrument in which the mechanism is accommodated in a shaft cylinder (grip housing 1).

However, according to the latter prior art, since the pressure pumping mechanism is inserted into the rear end opening of the refill, the outer diameter of the refill itself is increased, and as a result, the outer diameter of the shaft cylinder is increased.
In addition, since the volume of the space pressurized by the pressure pumping mechanism is relatively small in the latter prior art, when the writing liquid (ink W) in the refill is ejected by writing, the air in the space is depressurized. Then, the pressurizing effect disappears.
If it demonstrates in detail, the pressurization by a pressurization pumping mechanism (30) will be performed from the state shown in FIG. 5 of patent document 2 to the state shown in FIG. Within this range, only a small space between the jaw (35) and the writing liquid (ink W) is pressurized after the ventilation groove (33) is closed.
The space on the rear side of the guide bush (31) communicates with the outside through a clearance on the inner peripheral surface side of the holding portion (13) and a clearance on the rear side of the movable member (32), and therefore is pressurized. Never happen.
In the latter prior art, in order to enlarge the space to be pressurized, the refill diameter is increased or the filling amount of the writing liquid (ink W) in the refill is reduced, so that the writing liquid (ink W ) The rear space needs to be increased.
JP 2005-138356 A JP 2000-335173 A

  The present invention has been made in view of the above-described conventional circumstances, and the problem to be solved is that it is possible to reduce the shaft tube diameter and to prevent the pressurization effect from being reduced as the writing liquid is discharged. The object is to provide a pressure-type writing instrument that can be used.

  In order to solve the above-mentioned problem, a first invention is provided with a refill mounting portion capable of mounting a substantially tubular refill filled with writing liquid between a writing portion on the front end side and an opening on the rear end side. A piston member that can be approached and separated from the rear of the refill at the time of rearward movement, and a forward / backward mechanism for moving the piston member in the axial direction by an external operation. Between the writing fluid and the piston member, and a pressurizing writing instrument configured to form a pressurizing space portion compressed by advancing the piston member, wherein the refill mounting portion has an inner periphery of the shaft cylinder. A refill airtight means for airtightness between the surface and the outer peripheral surface of the refill when attached is provided, and a predetermined amount can be moved in the axial direction on the outer peripheral side of the piston member relative to the piston member. In addition, an annular airtight member is provided so that the outer peripheral portion is brought into airtight contact with the inner peripheral surface of the shaft cylinder, and is in contact with the annular airtight member over the entire circumference on the rear side of the annular member in the piston member. When the annular airtight member and the airtight contact portion are separated from each other, the airtight contact portion communicates with the outside of the shaft cylinder on the centrifugal direction side with respect to the airtight contact portion. An air passage that communicates with the pressurizing space is provided on the centripetal direction side of the contact portion.

  Further, according to the second invention, the piston member is formed in a substantially bottomed cylindrical shape with the bottom portion directed rearward, so that the internal pressurizing space communicates with the pressurizing space portion. It is characterized by being part.

  According to a third aspect of the present invention, the refill mounting portion is provided so as to be movable in the axial direction, so that the writing portion of the refill when mounted on the refill mounting portion is projected and retracted from the front end of the shaft cylinder. From a first biasing member that biases the piston member rearward relative to the refill, and a first biasing member that biases the refill rearward relative to the shaft tube. A second biasing member having a large biasing force, and the piston member is moved away from the refill in the writing portion immersion state, and the writing portion is pushed to project the writing portion from the front end of the shaft cylinder. The advance / retreat mechanism is provided so as to advance and retreat between positions, and the piston part that has advanced so as to project the writing part is locked. I will release it Characterized in that it is configured to.

In addition, the said invention should just be the structure which can mount | wear with the said refill, ie, not having the said refill as an essential structural requirement.
Therefore, as a specific example according to the present invention, an aspect in which the refill is not provided may be used, or an aspect in which the refill is attached in advance may be used.

Since the present invention is configured as described above, the following effects can be obtained.
According to the first invention, since the member for pressurization is arranged behind the refill without providing the member for pressurization around the refill as in the conventional example, the shaft cylinder The diameter can be reduced, and as a result, a pressure-type writing instrument with a slim appearance can be provided.
Further, since the pressurization space is secured between the writing liquid in the refill when it is mounted and the piston member disposed on the rear side of the refill, the volume of the pressurization space is relatively large. Can be secured.
Therefore, even when the volume of the pressurizing space portion increases with the writing liquid being discharged from the writing portion by writing, the decompression of the pressurizing space portion can be relatively reduced.
Therefore, it is possible to prevent the pressurization effect from being reduced during writing, and thus to maintain a good discharge state of the writing liquid from the writing unit.

Furthermore, according to 2nd invention, the volume of the space part pressurized can be ensured still more by the auxiliary | assistant pressurization space part connected to a pressurization space part.
Therefore, it is possible to further reduce the pressure reduction associated with the discharge of the writing liquid from the writing part, and further reduce the reduction of the pressurizing effect during the writing, and the discharge state of the writing liquid from the writing part is longer. It can be maintained well.

Furthermore, according to the third invention, the pressurizing space is pressurized by a knocking operation for projecting the writing part, and the pressurized state is released by a re-knocking operation for immersing the writing part.
That is, since the operation of moving the writing part up and down and the operation of increasing and decreasing the pressure space part are linked to the same knocking operation, the usability is good.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
Although the pressure-type writing instrument concerning this invention can be comprised as a ball-point pen, a correction pen, etc., in this Embodiment, the pressure-type writing instrument 1 comprised as a correction pen is demonstrated as a particularly preferable aspect.
In the present specification, “front” means the writing part 22 direction (left direction in FIG. 1), and “rear” means the opposite direction to the writing part 22 direction.

  The pressure-type writing instrument 1 is equipped with a refill 20 in which a writing liquid 23 as a correction liquid is filled in a shaft cylinder 10, and a rear end side of the refill 20 is attached to the outer peripheral surface of the refill 20 and the inner periphery of the shaft cylinder 10. A refill mounting portion 30 that is hermetically sealed to the surface, a piston member 40 that can be approached and separated from the refill 20 from behind, and a first biasing member 50 that biases the piston member 40 rearward relative to the refill 20; The second urging member 60 that urges the refill 20 rearward relative to the shaft cylinder 10 and the advance / retreat mechanism 70 that advances and retracts the piston member 40 in the axial direction by an external operation are provided, and the writing liquid 23 in the refill 20 is provided. A pressure space S1 is secured between the piston member 40 and an auxiliary pressure space S2 is secured in the piston member 40.

  The shaft cylinder 10 includes a front shaft 11 constituting a front opening portion 11a and a grip portion 11b, and a rear shaft 12 constituting a portion on the rear side of the front shaft 11, and from the rear shaft 12. Further, an advancing / retreating mechanism 70 described later is fitted on the rear end side.

  The front shaft 11 is formed in a substantially cylindrical shape having a tapered leading end portion 11a on the front end side and a grip portion 11b on the rear side from the leading end portion 11a.

The rear shaft 12 is a substantially cylindrical member that is screwed to the rear end side of the front shaft 11.
The rear shaft 12 has a regulation step portion 12a on its inner peripheral surface. The restriction step portion 12a is a step portion whose diameter is increased on the front side so as to engage with a refill attachment portion 30 described later and restrict the rearward movement of the refill attachment portion 30.
In the rear shaft 12, the cylindrical inner surface on the rear side of the regulation step portion 12 a is a surface for slidingly contacting a refill mounting portion 30 and a piston member 40 described later.

  The shaft tube 10 may be a member in which the front shaft 11 and the rear shaft 12 are integrated, or a member in which the front end portion is separated.

  The refill 20 includes a substantially cylindrical writing liquid storage tube 21, a writing unit 22 connected to the front end side of the writing liquid storage tube 21, and a writing liquid 23 filled in the front side of the writing liquid storage tube 21. And a grease-like follower 24 filled so as to be in contact with the end of the writing liquid 23. As another example, a solid follower rod can be provided in the grease-like follower 24.

  The writing unit 22 is a so-called ball-point pen tip in which a transfer ball is rotatably held at the most distal portion and exposed.

Further, the writing liquid 23 is a white correction liquid according to an example of the present embodiment, and the viscosity thereof is appropriately set so as to be smoothly discharged through the transfer ball.
The viscosity of the writing solution 23 will be described in detail. When a viscoelasticity measuring device manufactured by Pear Physica is used and the cone diameter is 50 mm, the cone angle is 2 °, and the temperature is 20 ° C., the shear rate in steady rotation is 1. The viscosity value at / s is in the range of 0.8 to 500 Pa · s, and when the shear rate is 100 / s, the viscosity value of the writing solution 23 is in the range of 0.02 to 130 Pa · s. It is assumed to be inside.

  The follower 24 is a grease-like fluid that follows the decrease in the writing liquid 23, has no compatibility with the writing liquid 23, and has a characteristic of preventing the writing liquid 23 from evaporating.

The refill mounting portion 30 is a substantially cylindrical member that can be mounted in an annular shape on the rear end side of the writing liquid storage tube 21 of the refill 20, and is locked to the regulation step portion 12 a of the rear shaft 12 on the front end side. It has the convex part 31 and can advance / retreat integrally with the refill 20 to be mounted.
The refill mounting portion 30 has an annular recess 32 formed on the outer peripheral surface on the rear end side, and an annular airtight member 33 for refill is included in the annular recess 32, and the inner peripheral surface of the refill mounting portion 30 is refilled. The refill airtight means for sealing the space between the outer peripheral surface of the refill 20 to be mounted and the inner peripheral surface of the shaft cylinder 10 is configured by fitting and intimately contacting the rear end side of the 20 writing liquid storage tube 21.
In addition, although the control step part 12a and the convex part 31 of the rear shaft 12 are formed in an annular shape extending in the circumferential direction of the shaft tube 10 according to the illustrated example, as another example, a part in the circumferential direction of the shaft tube 10 An uneven portion may be used.

  The refill annular hermetic member 33 is an annular elastic body that is in close contact with the bottom surface of the annular recess 32 and in close contact with the inner peripheral surface of the rear shaft 12 of the shaft cylinder 10, and is, for example, a rubber O-ring.

Therefore, according to the refill mounting portion 30 configured as described above, the refill 20 can be moved in the front-rear direction in a state in which the space between the outer peripheral surface of the refill 20 and the inner peripheral surface of the shaft cylinder 10 is hermetically sealed. The backward movement is restricted at a predetermined position.
Note that the refill airtight means (in other words, the structure that seals the periphery of the refill 20) may be other than the aspect using the refill mounting portion 30, for example, directly from the elastic body to the outer periphery of the refill 20 It is also possible to provide a structure provided with an airtight member.

Further, the piston member 40 is formed in a substantially bottomed cylindrical shape with the bottom portion 40a facing rearward, so that the internal space serves as an auxiliary pressurizing space portion S2 communicating with the pressurizing space portion S1.
The piston member 40 has a large-diameter portion 40b in which the outer diameter of the front end side portion is enlarged, and an annular recess 41 is formed on the outer peripheral surface of the large-diameter portion 40b. Further, an annular airtight member 42 for the piston member is inserted.
In addition, although the piston member 40 of the example of illustration is comprised as one component, in order to improve productivity etc., you may make it comprise from two or more components.

The annular airtight member 42 for the piston member has an outer diameter portion in contact with the inner peripheral surface of the rear shaft 12 and an inner diameter portion having a gap with the bottom 41b of the annular recess 41 in the axial direction within the annular recess 41. An annular elastic body provided so as to be movable, for example, a rubber O-ring.
A lubricant is applied to the outer surface of the piston member annular airtight member 42 in order to improve the axial movement in the annular recess 41.

An airtight contact portion 41 a is provided on the rear end surface in the annular recess 41.
The airtight abutting portion 41a can abut against the annular airtight member 42 for the piston member over the entire circumference from the rear side. According to the illustrated example, the airtight abutting portion 41a is a flat rear end surface in the annular recess 41. Therefore, the contact property is improved.

  An air passage is constituted by the first air passage 40b1 and the second air passage 40b2 in a range extending from the centrifugal direction side to the centripetal direction side with respect to the airtight contact portion 41a. This air passage is blocked by the contact of the annular airtight member for piston member 42 with the airtight contact portion 41a, and is opened when the annular airtight member for piston member 42 is separated from the airtight contact portion 41a.

The first air passage 40b1 is a passage which communicates the space in the annular recess 41 to the outside of the shaft cylinder on the centrifugal direction side with respect to the airtight contact portion 41a.
More specifically, the first air passage 40b1 includes the outer diameter of the rear portion of the large-diameter portion 40b relative to the annular recess 41, the inner peripheral surface of the shaft cylinder 10 (specifically, the inner diameter of the rear shaft 12). (Peripheral surface). This gap communicates with the outside air behind the shaft cylinder 10 via a gap between the rear outer peripheral surface of the piston member 40 and the inner peripheral surface of the shaft cylinder 10 and a gap between components constituting the advance / retreat mechanism 70 described later. is doing.
In addition, as another example of the first air passage 40b1, a through hole or a groove communicating with the space on the rear side of the large-diameter portion 40b from the annular concave portion 41 on the centrifugal direction side of the airtight contact portion 41a in the rear portion of the large-diameter portion 40b May be formed.

The second air passage 40b2 is a passage that communicates the annular recess 41 with the pressurizing space S1 on the centripetal side of the airtight contact portion 41a.
If it demonstrates in detail, this 2nd ventilation path 40b2 is comprised by the groove | channel of the axial direction (left-right direction according to FIG. 1) formed in the outer peripheral surface ahead of the annular recessed part 41 in the large diameter part 40b. Yes.

In addition, the front end face of the large diameter portion 40b of the piston member 40 is provided with one or a plurality of ventilation grooves 40b3 extending in the radial direction.
The ventilation groove 40b3 is a groove that communicates the second ventilation path 40b2, the pressurizing space portion S1, and the auxiliary pressurizing space portion S2. When the front end surface of the large diameter portion 40b abuts the rear end surface of the refill mounting portion 30 In the state shown in FIGS. 2 to 4, the air pressure in the pressurizing space S <b> 1 and the auxiliary pressurizing space S <b> 2 is transmitted into the annular recess 41.

As another example of the second air passage 40b2, a through hole that communicates the annular recess 41 and the pressurizing space S1 may be provided in the front portion of the large diameter portion 40b.
Furthermore, as another example of the second ventilation path 40b2, a through hole communicating in the radial direction can be provided in the bottom 41b of the annular recess 41.
That is, the second air passage 40b2 may be configured to communicate with the pressurizing space S1 or the auxiliary pressurizing space S2.

  Further, the rear end side of the piston member 40 is formed so as to be pushed by an advance / retreat mechanism 70 which will be described later, and also functions as a shaft portion that rotatably supports the rotor 72 of the advance / retreat mechanism 70.

According to the above configuration, the pressurization space S1 is secured between the rear end surface of the follower 24 in the refill 20 and the front end surface of the piston member 40, and the auxiliary pressurization space S2 is secured in the piston member 40. . And these pressurization space part S1 and auxiliary | assistant pressurization space part S2 become the pressurization space connected to the axial direction.
Here, the volume of the auxiliary pressurizing space portion S2 in the piston member 40 is preferably about 1/3 or more of the volume of the pressurizing space portion S1 in consideration of the reduced pressure accompanying the discharge of the writing liquid 23. Furthermore, it is preferable to set it to about 1/2 or more of the volume of the pressurizing space S1.

  The first urging member 50 is a coiled compression spring. One end of the first urging member 50 is engaged with a step on the inner peripheral surface of the rear end side of the refill mounting portion 30, and the other end is connected to the inner periphery of the piston member 40. The piston member 40 is urged rearward relative to the refill 20 by being engaged with the stepped portion of the surface and disposed between the refill 20 and the piston member 40.

  The second urging member 60 is a coiled compression spring having a larger urging force than that of the first urging member 50, and one end of the second urging member 60 is engaged with the stepped portion on the inner peripheral surface of the tip end portion 11 a of the shaft tube 10. While stopping, the other end side is latched by the step part of the outer peripheral surface of the front end side of the refill 20, and the refill 20 is urged | biased toward the axial cylinder 10 back.

The advancing / retreating mechanism 70 is connected to the rear end of the shaft cylinder 10 and has a rear end cylindrical member 71 having an inner frame portion 71 a on the inner peripheral surface, and a rotor disposed in the rear end cylindrical member 71. 72 and a knock member 73 that is engaged with the rear side of the rotor 72 and is exposed behind the rear end tubular member 71.
The advance / retreat mechanism 70 advances the rotor 72 when the knock member 73 is pushed forward by a knock operation against the urging force of the first urging member 50 and the second urging member 60. The locked state is configured to be released when a knocking operation is performed again.
The front end side of the rotor 72 is engaged with the piston member 40 so as to contact from behind and rotate in the circumferential direction.

Therefore, according to the advancing / retreating mechanism 70 configured as described above, the piston member 40 is locked in a state of being advanced so as to project the writing portion, and this locked state is released when the knocking operation is performed again from the outside. Will be.
The advance / retreat mechanism 70 may have another configuration as long as the piston member 40 is locked or released as described above.

Next, the characteristic effect of the pressure type writing instrument 1 having the above-described configuration will be described in detail.
First, as an initial state, when the writing unit 22 is in an immersive state and no knocking operation is performed, the refill 20 is urged backward by the second urging member 60 as shown in FIG. At the same time, the writing portion 22 is maintained in an immersed state by locking the convex portion 31 of the refill mounting portion 30 to the regulation step portion 12a on the inner peripheral surface of the shaft tube 10.
In this state, the piston member 40 is urged rearward by the first urging member 50, so that the piston member 40 is maintained at the retracted position separated from the refill mounting portion 30.
Therefore, the pressurizing space portion S1 and the auxiliary pressurizing space portion S2 are secured between the writing liquid 23 in the refill 20 (specifically, the rear end surface of the follower 24) and the bottom portion 40a in the piston member 40. .
The rearward movement of the piston member 40 is restricted by the knock member 73 behind the piston member 40 being locked to the rear end tubular member 71 around the piston member 40.

When the piston member 40 is in the retracted position, as shown in the enlarged view of FIG. 1, the piston member 40 is in a state where a gap is secured between the piston member annular airtight member 42 and the airtight contact portion 41a. An annular airtight member 42 for members is loosely fitted.
Therefore, the piston member 40 rear side and the pressurizing space S1 are formed by the gap, the gap between the piston member annular airtight member 42 and the bottom 41b of the annular recess 41, the first ventilation path 40b1, the second ventilation path 40b2, and the like. A communicating air passage is formed. And since this ventilation path is connected with external air by the clearance gap between the components in the advancing / retreating mechanism 70, pressurization space part S1 and auxiliary | assistant pressurization space part S2 will be in the state of substantially atmospheric pressure.

Next, as shown in FIG. 2, when the piston member 40 moves forward against the urging force of the first urging member 50 by the advance / retreat mechanism 70, the air in the pressurizing space portion S1 and the auxiliary pressurizing space portion S2 is It flows out through the second air passage 40b2 and the first air passage 40b1 to the rear in the shaft cylinder. Therefore, the annular airtight member for piston member 42 is pushed by the air flowing from the pressurized space S1 second air passage 40b2 to the first air passage 40b1, moves rearward relative to the piston member 40, and makes airtight contact. It contacts the part 41a. The backward movement of the piston member annular airtight member 42 is also assisted by the outer diameter portion of the piston member annular airtight member 42 being in sliding contact with the inner peripheral surface of the shaft tube 10.
Therefore, the pressurizing space portion S1 and the auxiliary pressurizing space portion S2 are sealed, and the air in the pressurizing space portion S1 and the auxiliary pressurizing space portion S2 is compressed.
Since the urging force of the first urging member 50 is set to be smaller than the urging force of the second urging member 60, the refill is within the moving range from the retracted position until the piston member 40 contacts the refill mounting portion 30. No. 20 does not move forward until the writing state is reached, but may slightly move due to sudden pressure fluctuations in the pressurizing space S1 and the auxiliary pressurizing space S2.

  Further, when the piston member 40 continues to advance, the refill 20 advances as the piston member 40 advances, and the refill 20 advances until the writing portion 22 reaches the maximum protruding position (the state shown in FIG. 3). To do. Even during this forward movement, the contact state between the airtight contact portion 41a and the piston member annular airtight member 42 is maintained, so that the pressurized state of the pressurizing space portion S1 and the auxiliary pressurizing space portion S2 is also maintained. The

  Next, when the pressing force to the knock member 73 is released, the rotor 72 in the advance / retreat mechanism 70 is slightly retracted and locked, so that the refill 20 and the piston member 40 are also slightly retracted in conjunction with the movement. As shown in FIG. 4, the usable state where the writing unit 22 protrudes is maintained.

When the piston member 40 is slightly retracted as described above, the contact state between the airtight contact portion 41a and the piston member annular airtight member 42 is the pressure of the compressed air in the pressurizing space portion S1 and the auxiliary pressurizing space portion S2. Maintained by
More specifically, in the state where the front end surface of the piston member 40 (specifically, the front end surface of the large diameter portion 40b) and the rear end surface of the refill mounting portion 30 are in contact with each other, An air passage is formed by the ventilation groove 40b3. Therefore, the pressurizing space portion S1 and the auxiliary pressurizing space portion S2 communicate with the inside of the annular recess 41 by the ventilation groove 40b3.
In the contact state, as shown in FIGS. 3 to 4, even if the piston member 40 is slightly retracted, the piston member annular airtight member 42 has an annular recess from the pressurizing space S <b> 1 and the auxiliary pressurizing space S <b> 2. 41 is pressed against the airtight contact portion 41a by being pressed by the pressure of the air flowing into the airtight portion 41, so that no gap is generated between the airtight contact portion 41a. Therefore, the compressed state of the pressurizing space portion S1 and the auxiliary pressurizing space portion S2 is maintained.
In the illustrated example, a preferable example in which the ventilation groove 40b3 is provided at the front end of the piston member 40 is shown. However, as another example, even if the ventilation groove 40b3 is omitted, an elastic body is provided at the front end of the piston member 40. Since there is no airtight material such as, a clearance for communicating the pressurizing space portion S1 and the auxiliary pressurizing space portion S2 with the annular recess 41 is ensured between the front end surface of the piston member 40 and the rear end surface of the refill mounting portion 30. Is possible.

In the usable state shown in FIG. 4, the writing liquid 23 and the follower 24 in the refill 20 are pushed forward by the pressure of the compressed air in the pressurizing space portion S1 and the auxiliary pressurizing space portion S2. The discharge state of the writing liquid 23 from 22 can be maintained satisfactorily.
Further, according to the pressure-type writing instrument 1 of the present embodiment, a relatively large compression space is secured by the pressure space portion S1 and the auxiliary pressure space portion S2. Even if the air pressure in S1 and the auxiliary pressurizing space S2 is reduced, the amount of reduced pressure can be made relatively low, and as a result, a good discharge state of the writing liquid 23 can be maintained for a long time.

Further, as shown in FIG. 5, when the piston member 40 is retracted by the release operation of the advance / retreat mechanism 70, the air in the pressurizing space portion S1 and the auxiliary pressurizing space portion S2 is rapidly depressurized. The annular airtight member 42 moves relatively forward in the annular recess 41. The movement of the piston member annular airtight member 42 at this time is also assisted by the outer diameter portion of the piston member annular airtight member 42 being in sliding contact with the inner peripheral surface of the shaft tube 10.
Therefore, a gap is generated between the piston member annular airtight member 42 and the airtight contact portion 41a, and this gap, the gap between the piston member annular airtight member 42 and the bottom 41b of the annular recess 41, the first air passage 40b1. The second air passage 40b2 and the like form a continuous air passage, and the outside air flows into the pressurizing space portion S1 and the auxiliary pressurizing space portion S2 through this air passage.

Then, when the piston member 40 is further retracted, the writing unit 22 is immersed and returns to the initial state (the state shown in FIG. 1).
In this return state, as described above, the pressurizing space portion S1 and the auxiliary pressurizing space portion S2 communicate with the outside air and are maintained at a substantially atmospheric pressure, so that the writing liquid 23 in the refill 20 is added to the pressurizing space portion S1. In addition, the air pressure in the auxiliary pressurizing space S2 does not unintentionally flow out of the writing unit 22.

  In addition, according to the pressure-type writing instrument 1 of the said embodiment, although the aspect which comprised the refill 20 previously is shown, it is good also as an aspect which does not comprise the refill 20 as another example. That is, the refill 20 prepared separately may be attached later.

  Moreover, although the pressure-type writing instrument 1 of the said embodiment was used as the correction pen, it is also possible to comprise a ball-point pen by using the writing liquid 23 as the ink for ball-point pens. According to this configuration, it is possible to provide a ballpoint pen that can improve ink discharge by a pressurizing operation. For example, it is possible to provide a ballpoint pen that does not easily wrinkle during upward writing.

Next, in the pressure-type writing instrument 1, the difference in pressure performance depending on the presence or absence of the auxiliary pressure space S2 will be described based on the experimental results shown in FIG.
FIG. 6 shows the change in the ink amount due to writing and the pressure during pressurization for each of the pressure-type writing instrument 1 having the above-described configuration and the configuration (not shown) in which the auxiliary pressure space S2 is omitted from the pressure-type writing instrument 1. Shows the relationship. The configuration in which the auxiliary pressurizing space portion S2 is omitted is a configuration in which the space in the piston member 40 is filled with a solid such as a synthetic resin in the pressurizing writing instrument 1 described above.
In the pressurizing writing instrument 1 having the auxiliary pressurizing space portion S2, as shown by the solid line in FIG. 6, when the ink amount is reduced from the initial specified amount to zero, the pressure during pressurization is about 1.9 atm to about Decrease to 1.3 atm. Therefore, the pressure difference at that time is about 0.6 atm.
Further, in the pressure-type writing instrument without the auxiliary pressure space S2, when the ink amount is reduced from the initial specified amount to zero as shown by a one-dot chain line in FIG. 6, the pressure at the time of pressurization is about 3.0 atm. To about 1.4 atm. Therefore, the pressure difference at that time is about 1.6 atm.
That is, in the pressure-type writing instrument 1 having the auxiliary pressurizing space portion S2, the pressure reduction during pressurization accompanying the decrease in the ink amount due to writing is significantly smaller than that of the pressure-type writing instrument having no auxiliary pressure space portion S2. I can say that.
Therefore, according to the pressure-type writing instrument 1, a stable ink discharge amount can be maintained regardless of the ink decrease amount of the refill 20, and as a result, a good writing feeling can be obtained even when the remaining amount of ink is reduced. Can do.

It is sectional drawing which shows an example of the pressurization type writing instrument concerning this invention, and has shown the state by which the pressurization space part is not pressurized. It is sectional drawing which shows an example of the pressurization type writing instrument, and has shown the state by which the pressurization space part was pressurized by knock operation. It is sectional drawing which shows an example of the pressurization type writing instrument, and has shown the state which the writing part protruded to the limit position by the further knock operation. It is sectional drawing which shows an example of the same pressurization type writing instrument, and shows the state by which the piston member was latched by the advancing / retreating mechanism in the protrusion state of the writing part. It is sectional drawing which shows an example of the same pressurization type writing instrument, and is the state after the latching state by an advance / retreat mechanism is cancelled | released, Comprising: The state in the middle of the advance / retreat mechanism retreating is shown. It is a graph which shows the difference in the pressurization performance by the presence or absence of a pressurization space part.

Explanation of symbols

1: Pressure type writing instrument 10: Shaft cylinder 20: Refill 22: Writing part 23: Writing liquid 30: Refill airtight means 40: Piston member 40b1: First air passage 40b2: Second air passage 41: Annular recess 41a: Airtight contact Part 42: annular airtight member for piston member 50: first urging member 60: second urging member 70: advance / retreat mechanism S1: pressure space part

Claims (3)

A refill mounting portion capable of mounting a substantially tubular refill filled with writing liquid between the writing portion on the front end side and the opening on the rear end side, and the refill when mounted can be approached and separated from the rear. The piston member is provided in the shaft cylinder, and is provided with an advance / retreat mechanism that advances and retracts the piston member in the axial direction by an external operation, and between the writing liquid in the refill when attached and the piston member, A pressure-type writing instrument designed to form a pressure space compressed by the advance of the piston member,
The refill mounting portion is provided with refill airtight means for hermetically sealing between the inner peripheral surface of the shaft tube and the outer peripheral surface of the refill when mounted.
An annular airtight member is provided on the outer peripheral side of the piston member so as to be movable by a predetermined amount in the axial direction relative to the piston member, and to bring the outer peripheral portion into airtight contact with the inner peripheral surface of the shaft cylinder,
On the rear side of the annular member in the piston member, an airtight contact portion capable of contacting the annular airtight member over the entire circumference is provided,
When the annular airtight member and the airtight contact portion are separated from each other, the airtight contact portion communicates with the outside of the shaft cylinder on the centrifugal direction side, and the airtight contact portion on the centripetal direction side. A pressure-type writing instrument comprising an air passage communicating with the pressure space.   The said piston member is formed in the substantially bottomed cylindrical shape which turned the bottom part back, The inside space is made into the auxiliary pressurization space part connected to the said pressurization space part, It is characterized by the above-mentioned. The pressure-type writing instrument according to 1. By providing the refill mounting portion movably in the axial direction, a pressure-type writing instrument that causes the writing portion of the refill when mounted on the refill mounting portion to appear and disappear from the front end of the shaft cylinder,
A first urging member that urges the piston member rearward relative to the refill, and a urging force that urges the refill rearward relative to the shaft tube and has a larger urging force than the first urging member. Two biasing members,
The piston member is provided so as to advance and retreat between a position separated from the refill in the writing part immersion state and a position where the writing part is pushed from the front end by pushing the refill.
The advance / retreat mechanism is configured to lock the piston portion that has advanced so as to protrude the writing portion, and to release the locked state when a knocking operation is performed from the outside again. The pressure-type writing instrument according to claim 1 or 2.

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