JPH0794198B2 - Writing instrument - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a writing instrument in which liquid ink is directly contained in an ink chamber. To further specify the present invention, the above ink chamber is provided with a slidable slide plug that partitions the ink contained therein and air, and further, the internal volume of the ink chamber when the pen pressure is applied. The present invention relates to a writing instrument such as a whiteboard marker having a pump mechanism that reduces the amount of ink and pressurizes ink, and adopts a structure that ensures the sliding of the slide plug.

[0002]

2. Description of the Related Art Conventionally, a writing instrument has been often used in which an ink chamber in a main body is filled with batting, and the batting is held by ink by a capillary phenomenon. However, such a pad-shaped writing instrument has a small amount of ink that can be stored, and the amount of ink that can be supplied from this batting to a pen body such as a ball tip or a felt tip is small, so that the handwriting is faint when writing quickly. was there.

Recently, various so-called direct liquid type writing instruments have been developed in which liquid ink is directly contained in the ink chamber. Such a direct liquid type writing instrument is provided with a slide stopper that is slidable while maintaining liquid tightness in the ink chamber. The slide stopper separates liquid ink from air and consumes ink. Follow and slide. Such a direct liquid type writing instrument has an advantage that a large amount of ink is stored, the flow rate of ink supplied to the pen body can be increased, and the handwriting is not faded even if writing is performed quickly.

However, in such a direct liquid type writing instrument,
Since a large amount of liquid ink is directly supplied to the pen body, it is necessary to control the supply flow rate of this ink. With writing instruments such as water-based ballpoint pens and underline markers,
A valve mechanism for controlling the supply of ink is arranged between the ink chamber and the pen body to control the supply amount of the ink. In addition, in these writing instruments, the capillary force of the pen body such as a ball tip or felt tip is large, and the pen body itself has a considerable ink suction ability and ink sealing ability, so that it is relatively easy to control the ink supply amount. Is.

However, it is difficult for the whiteboard marker and the paint marker to control the ink supply amount in the case of the direct liquid type. That is, with these writing instruments,
The writing surface is a whiteboard, metal or plastic surface, and unlike paper, it does not absorb water. Therefore, in these writing instruments, a thick handwriting cannot be obtained unless a pen body having a small capillary force such as a felt tip is used and a large amount of ink or paint is contained in the felt tip. However, such a pen body has a small ink sucking ability and a sealing ability of the pen body itself.
For this reason, when the pen body is directed downward, there is a problem that the head pressure of the ink in the ink chamber excessively contains ink in the pen body or causes the ink to drop. In order to prevent such a problem, it is necessary to make the sliding resistance of the slide plug large enough to support the head pressure. However, as described above, since the pen body has a small suction capacity, it is difficult to absorb the ink in the ink chamber by overcoming the sliding resistance of the slide plug. Particularly, in the case of a whiteboard marker, since the writing tool is written in a substantially horizontal state, the head pressure of the ink in the ink chamber becomes almost zero in this state, so that it is more difficult to suck the ink.

Such a problem cannot be essentially solved by providing a valve mechanism for controlling the supply of ink between the pen body and the ink chamber. For this reason, such a whiteboard marker or paint marker is provided with a pump mechanism that holds this pen body slidably with respect to the main body and pushes out the ink inside when the pen body retracts due to writing pressure. In addition, a check valve mechanism has been developed which is provided between the pump mechanism and the ink chamber and allows only the flow toward the pump mechanism. In such a case, the pump mechanism pumps ink to the pen body by a predetermined amount according to the writing pressure when writing, so that it is possible to always contain sufficient ink in the pen body and control the ink amount. it can.

However, such a structure has a complicated structure and is expensive. Since such whiteboard markers and paint markers are disposable types,
The cost needs to be reduced as much as possible. Further, in such a device, when the writing pressure acting on the pen body is released, the pump mechanism is returned by a spring or the like to draw out the ink in the ink chamber. In this case, the slide stopper moves in proportion to the amount of the drawn ink, but the amount of the drawn ink is small and the amount of movement of the slide stopper is extremely small. This slide plug is generally formed of an elastic material such as silicone rubber, and an outer peripheral surface thereof is provided with an annular seal portion for contacting the inner peripheral surface of the ink chamber and maintaining a seal. The slide stopper moves slightly from the stationary state with each operation of the pump mechanism, that is, with each writing of one character. However, the static friction coefficient between the seal portion and the ink chamber inner surface is high, In some cases, the slide stopper does not move, and the slide stopper or the seal portion only elastically deforms. In such a case, the ink chamber becomes a negative pressure, and this negative pressure acts on the pen body via the check valve mechanism and the pump mechanism to pull back the ink contained in the pen body. Therefore, the amount of ink contained in the pen body is reduced, and in some cases, air is drawn into the tip portion of the pen body. When this happens, there is a problem that the first part of the handwriting becomes faint when writing the next character.

In order to solve such a problem, it is sufficient to reduce the initial resistance force when the slide stopper starts moving from the stationary state. To do this, the seal portion and the inner peripheral surface of the ink chamber are reduced. The contact pressure with and must be made extremely small, and there is a limit to the reduction of the initial resistance of the slide stopper due to the limit of manufacturing accuracy. Therefore,
With a whiteboard marker or the like having the above structure, it is difficult to completely stabilize the ink supply to the pen body.

[0009]

SUMMARY OF THE INVENTION The present invention has been made based on the above circumstances and has a simple structure and is capable of stably controlling the supply of ink to a pen body. And other writing instruments.

[0010]

SUMMARY OF THE INVENTION The present invention comprises a pen body that is movable by writing pressure, and a pump mechanism that operates by the movement of the pen body. No check valve mechanism or the like is provided between the pump mechanism and the ink chamber. When the pen body retracts, the pump mechanism reduces the internal volume of the ink chamber, It is configured to press the ink.

Further, a slide stopper is provided in the ink chamber, and a seal portion made of an elastic material is projectingly provided on an outer peripheral surface of the slide stopper, and a tip end surface of the seal portion is brought into close contact with an inner peripheral surface of the ink chamber. is doing. The axial width of the contact surface of the seal portion is A. In addition, writing pressure acts on the pen body by writing, and the pump mechanism pressurizes the ink chamber so that the ink is pushed out to the pen body side and the pressurization moves the slide stopper. The amount of movement of the slide stopper at this time is B. And
When a standard writing pressure is applied to this pen body, for example, when a writing pressure of 100 grams is applied in the case of a whiteboard marker, the movement amount B of the above slide stopper is more than the width A of the contact portion of the seal portion. The stroke and elastic force of the pump mechanism are set so as to be large.

[0012]

Since the seal portion of the above slide stopper is made of an elastic material, its contact surface is elastically and completely adhered to the inner peripheral surface of the ink chamber in a stationary state. Ink has been removed and is in direct contact.
Therefore, this static friction coefficient is large. When one character is written with this writing tool and a writing pressure is applied to the pen body, the ink chamber is pressurized by the pump mechanism, and the slide stopper moves backward. When a standard writing pressure, for example, a writing pressure of 100 grams in the case of a whiteboard marker is applied, the stroke amount of the pump mechanism or the stroke amount of the pump mechanism is set so that the movement amount B of the slide stopper becomes larger than the width A of the contact surface of the seal portion. Elasticity etc. are set. Therefore, the seal portion completely moves from the portion of the inner peripheral surface of the ink chamber that was in close contact before the movement, and the portion of the inner peripheral surface of the ink chamber that was in close contact before the movement was wetted with ink.

Next, when the writing pressure for one character is completed and the writing pressure is released, the pump mechanism is returned by the urging force, the slide plug is advanced to the position before the movement, and only the ink consumption amount is satisfied. Move forward by. In this case, the inner peripheral surface of the ink chamber in which the seal portion was located before the movement was wetted with the ink, and the forward movement of the slide stopper caused the gap between the close contact surface of the seal portion and the inner peripheral surface of the ink chamber. An ink film intervenes there to perform a lubricating action. For this reason, the resistance of the slide plug during the forward movement is extremely small, the slide plug slides smoothly to a position commensurate with the ink consumption amount, and the negative pressure in the ink chamber as described above does not occur. Therefore, the supply of ink to the pen body is stable. When the slide stopper is stationary, the ink film between the seal portion and the inner peripheral surface of the ink chamber is eliminated by the elasticity of the seal portion in a short time, and the same operation as above is repeated.

Further, since the ink film has a lubricating action when the slide plug advances as described above, the initial resistance of the slide plug may be large. Therefore, the pressure when the writing pressure acts on the pen body to pressurize the ink in the ink chamber is a pressure corresponding to the sliding resistance when the slide plug is retracted. Therefore, when retracting this slide stopper

By appropriately setting the sliding resistance, the pressure in the ink chamber when the writing pressure acts on the pen body and the pump mechanism operates can be set to a predetermined pressure. Therefore, such a writing instrument does not require a check valve mechanism,
The structure is simple. Further, even if an excessively strong writing pressure is applied, the amount of retreat of the slide plug is increased, and the pressure in the ink chamber does not become excessive. Therefore, the ink supply is more stable than that provided with the check valve mechanism.

[0016]

Embodiments of the present invention will be described below with reference to the drawings. 1 to 3 show a first embodiment of the present invention.
In this embodiment, the present invention is applied to a whiteboard marker. Reference numeral 1 in the figure denotes a main body of the whiteboard marker, which has a cylindrical shape, and the inside thereof is formed in the ink chamber 2. A pen holder 3 is attached to the front end of the main body 1. The pen body holder 3 is provided with a pen body, and in the case of this embodiment, a felt tip 4 slidably in the axial direction, and is configured to move in the axial direction by the writing pressure during writing. .

A pump mechanism 5 is provided between the pen body 4 and the ink chamber 2. This pump mechanism 5
Is configured as follows. That is, a cylindrical holding portion 6 is formed at the rear end of the pen body holder 3, and a piston body 7 made of an elastic material such as silicone rubber is fitted in the holding portion 6. A hole is formed through the center of the piston body 7. A fitting portion 8 having a reduced diameter is formed at the rear end portion of the felt tip 4, and the fitting portion 8 is fitted in the hole of the piston body 7.

Therefore, when writing with the whiteboard marker, if the writing pressure acts on the felt tip 4, the felt tip 4 is retracted, and the piston body 7 is deformed as shown in FIG. Ink chamber 2
The internal volume of the inside is reduced and the ink in the ink chamber 2 is pressurized. When the writing pressure is released, the piston body 7 returns to the state shown in FIG. 1 due to its elasticity, and in this case, the internal volume in the ink chamber 2 increases.

A slide plug 9 is slidably provided in the ink chamber 2. This slide stopper 9
For example, it is made of an elastic material such as fluorine-based silicone rubber or other silicone rubber, and an annular seal portion 10 is integrally provided on the outer peripheral surface thereof. The top surface of the seal portion 10 is elastically deformed and adheres to the inner peripheral surface of the ink chamber 2 to maintain the sealing property. The axial width of the contact surface of the seal portion 10 with the inner peripheral surface of the ink chamber 2 in this state, that is, the seal width is A as shown in FIG.

A tail plug 11 is attached to the rear end of the body 1, and an air communication hole 12 is formed in the tail plug 11. The ink chamber 1 is filled with liquid ink, for example, quick-drying ink, and the ink and air are separated by the slide plug 9. The slide plug 9 slides in response to the consumption of the ink and the like, and the pressure inside the ink chamber 2 is always maintained at a pressure equal to the atmospheric pressure.

During writing, a writing pressure acts on the felt tip 4, the felt tip 4 retracts, the piston body 7 deforms as shown in FIG. When pressurized, a part of the ink flows through the hole of the piston body 7, flows through the felt tip 4 and the fitting portion 8, and is supplied. On the other hand, the pressurization in the ink chamber 2 causes the slide stopper 9 to move rearward as indicated by the chain double-dashed line in FIG. The movement amount B changes in accordance with the writing pressure applied to the felt tip 4, that is, the deformation amount of the piston body 7.

When a standard writing pressure, in this embodiment 100 g of writing pressure, is applied to the felt tip 4, the amount B of movement of the slide stopper 9 is the sealing portion 10 of the slide stopper 9. To be larger than the seal width A,
The dimensions, elastic force, etc. of the piston body 7 are set.

With such a writing instrument, the writing pressure applied during writing varies greatly depending on the use condition and the writer. For example, when writing on a substantially vertical whiteboard surface with this whiteboard marker, when writing by pinching the tail of this whiteboard marker with a finger, only 5 to 10 grams of writing pressure is applied. It may not be. In the case of a writer who has a strong habit of writing strongly, or a writer who strongly presses the whiteboard marker against the writing surface at the end of writing, the instantaneous maximum writing pressure may reach several hundred grams. . However, JIS-S-60
In the writing test of the marking pen specified in 37, the standard writing pressure at the time of the test is specified to be 100 grams for the oil-based ink and 50 grams for the water-based ink. According to the test by the present inventors, in the case of this whiteboard marker, in the case of normal writing, the above-mentioned standard writing pressure is instantaneous in one writing or one writing. Has also been added. As in the present invention, even momentary writing pressure is sufficient to retract the slide plug by a predetermined amount. Therefore, in the case of this embodiment, if the retreat amount B of the slide stopper 9 is set to exceed the seal width A when the standard writing pressure of 100 grams acts, the effect of the present invention is achieved. Is enough to

The initial sliding resistance when the slide plug 9 starts moving from the stationary state is the load when the head pressure of the ink filled in the ink chamber 2 acts on the slide plug 9. It is set larger.

Next, the operation of the above embodiment will be described. First, when the slide stopper 9 is stationary without writing, the contact surface of the seal portion 10 is
The inner peripheral surface of the ink chamber 2 is in direct contact with the seal portion. In this state, the friction coefficient between them is relatively large, and the sliding resistance of the slide plug 9 is large.

Next, when writing with the whiteboard marker, writing pressure is applied to the felt tip 4 so that the felt tip 4 retracts and the pump mechanism 5 is pushed.
The piston body 7 is deformed and the ink in the ink chamber 2 is pressurized. At this time, although the slide stopper 9 is retracted, ink is not attached to the inner peripheral surface of the ink chamber 2 on the tail stopper 11 side of the seal portion 10 of the slide stopper 9 and is in a dry state. Therefore, when the slide plug 9 retracts, there is no ink film between the seal portion 10 and the inner peripheral surface of the ink chamber 2, and the slide plug 9 slides in a state of direct contact. Therefore, the sliding resistance of the slide plug 9 in this case is relatively large, and the pressure in the ink chamber 2 becomes a relatively high pressure corresponding to the sliding resistance when the slide plug 9 retracts. Then, under such a pressure, an amount of ink commensurate with the amount of ink consumed by one stroke of writing is felt.
The material of the felt tip 4, the diameter of the fitting portion 8 and the like are set so as to be sent to. Therefore, the felt tip 4 always contains an optimum amount of ink for writing.

In the case of the above-mentioned writing, when a standard writing pressure is applied, the moving amount B of the slide stopper 9 for retreating exceeds the seal width A of the seal portion 10. Therefore, the portion of the inner peripheral surface of the ink chamber 2 to which the seal portion 10 was in close contact before retreating is wetted with ink.

In some cases, or depending on the writer, excessive writing pressure may be applied. Even in such a case, however, the amount of ink in the ink chamber 2 is increased simply by increasing the retracted amount of the slide stopper 9. Since the pressure of the ink hardly changes, it is possible to stably supply the ink.

Next, when the writing pressure for one stroke is completed and the writing pressure is released, the piston body 7 is instantaneously returned by its own elastic force, and the pressure in the ink chamber 2 is negatively reduced. The pressure is applied, and the slide stopper 9 instantaneously advances to the position before the backward movement. In this case, since the portion of the inner peripheral surface of the ink chamber 2 which the seal portion 10 was in close contact with before the retreat is already wetted with ink, there is a gap between the seal portion 10 and the inner peripheral surface of the ink chamber 2. The ink film is present, and the sliding action of the slide film 9 is caused by the lubricating action of the ink film.
Sliding resistance is extremely small. Then, the slide plug 9 further advances from the position before retreating by a minute distance corresponding to the amount of ink consumed by writing for one stroke. In this case, since the seal portion 10 of the slide stopper 9 is in a state of being lubricated by the ink film as described above,
It moves smoothly over this minute distance. Therefore, unlike the conventional case, negative pressure does not remain in the ink chamber. Therefore, the ink contained in the felt tip 4 is not pulled back inside due to this negative pressure, and stable ink supply is possible.

By repeating the above-described operation, ink corresponding to the amount of ink consumed for each writing of one stroke is supplied to the felt tip 4, and writing is always performed on a non-water-absorptive writing surface such as a whiteboard. An appropriate amount of ink is contained in the felt tip 4.

Further, as described above, the felt tip 4 is made of material, density, etc. so that the capillary force becomes relatively weak so that it can be written deeply on a non-water-absorptive writing surface such as a whiteboard. It is set. Therefore, the ink holding ability of the felt tip 4 itself, that is, the sealing ability is low, and when the felt tip is directed downward, the head pressure of the ink in the ink chamber 2 causes the felt tip to excessively contain ink, It may drop. However, in this embodiment, the sliding resistance of the slide stopper 9 in the stationary state, that is, the sliding resistance when the ink film is not interposed between the seal portion and the inner peripheral surface of the ink chamber 2 is the ink resistance. Since it is set to a value large enough to support the head pressure of, the above-mentioned problems can be reliably prevented.

FIG. 4 shows a second embodiment of the present invention. This is a whiteboard marker in consideration of writing with excessively weak writing pressure. The second embodiment basically has the same configuration as that of the first embodiment described above. In FIG. 4, parts corresponding to those of the first embodiment are designated by the same reference numerals, and their description will be omitted. Is omitted.

That is, depending on the writer, there is a case where the user holds the rear end of the whiteboard marker and writes with an extremely weak writing pressure. The writing pressure in such a case is only about 10 grams. In such a case, in order to make the amount of movement B of the slide stopper 9 for retreat larger than the seal width A of the seal portion 10, the elastic force of the piston member 7 of the pump mechanism 5 is weakened and a small writing pressure is applied. However, the required stroke is obtained, and the sliding resistance when the slide stopper 9 is retracted, that is, the sliding resistance when the ink film is not present between the seal portion 10 and the inner peripheral surface of the ink chamber 2 is obtained. Must be small. With this arrangement, when the felt tip 4 is directed downward, the head pressure of the ink in the ink chamber 2 cannot be supported by the initial sliding resistance of the slide plug 9, and ink drops from the felt tip 4 may occur. There is a nature.

In the second embodiment shown in FIG. 4, a shutoff valve mechanism 20 is provided between the pump mechanism 5 and the ink chamber 2 in order to prevent such ink dripping. The shutoff valve mechanism 20 includes a housing 21, and the housing 21 is fitted in the main body 1. A tapered through hole 23 is formed in the housing 21, and the ink chamber 2 and the pump mechanism 5 are communicated with each other through the through hole 23. A steel ball 22 acting as a valve body is inserted in the through hole 23. Further, a cut-and-raised stopper 24 is provided on the inner surface of the rear end portion of the housing 21 so as to prevent the steel ball 22 from falling off.

Further, the piston body 7 of the above-mentioned pump mechanism 5
Is configured so as to come into contact with the casing 21 of the shutoff valve mechanism 20 so that the maximum stroke thereof is regulated. The casing 21 also serves as a stopper for regulating the maximum stroke of the pump mechanism 5.

When such a whiteboard marker is written in a substantially horizontal state, as shown in FIG. 4, the steel ball 22 falls off from the through hole 23 due to gravity,
The through hole 23 is opened, and ink is supplied from the ink chamber 2 to the pump mechanism. The other actions are similar to those of the first embodiment.

When the writing is stopped and the felt tip 4 is directed downward, the steel ball 22 is fitted into the tapered through hole 23 by gravity, and the through hole 23 is formed.
To block. Therefore, the supply of the ink is cut off, and the problem that the ink drops from the felt tip 4 is reliably prevented.

Further, the pump mechanism 5 of this embodiment is used.
Since the elastic force of the piston body 7 is set to be weak, the piston body 7 may be excessively deformed when a large writing pressure is applied, but the piston body 7 comes into contact with the casing 21 and Since the maximum stroke is regulated,
The above problems do not occur.

Further, FIG. 5 shows a portion of the slide stopper of the third embodiment. The slide stopper 9 of the third embodiment has a pair of seal portions 10a, 1 at both ends in order to stabilize the slide stopper.
0b is projected. Even in this case, the relationship between the seal width A of the seal portions 10a and 10b and the movement amount B of the slide plug 9 is the same as that in the above-described embodiment. In addition,
In this case, the portion between the pair of seal portions 10a and 19b may be filled with ink or may be filled with a lubricant.

The present invention is not limited to the above embodiment. For example, the pump mechanism is not limited to the one described above, and may be a bellows type, a diaphragm type, a sliding mechanical piston type, or any other type. Further, the slide stopper is not limited to the above-mentioned shape, and various other shapes and structures are adopted.

The present invention also provides a whiteboard marker,
Although it is suitable for a paint marker or the like, it goes without saying that it can also be applied to an underline marker and other writing instruments.

[0042]

As described above, according to the present invention, the check valve mechanism is not required, the structure thereof is simple, and the ink pressure when the pump mechanism is actuated has an essentially influence on its stroke. However, since it is affected only by the sliding resistance when the slide stopper retracts, it is possible to stabilize the amount of ink supplied to the pen body regardless of the strength of the writing pressure.
Has the effect of.

[Brief description of drawings]

FIG. 1 is a vertical sectional view of a first embodiment.

FIG. 2 is a vertical sectional view of another operating state of the first embodiment.

FIG. 3 is an enlarged vertical sectional view of a portion of the slide stopper according to the first embodiment.

FIG. 4 is a vertical sectional view of a second embodiment.

FIG. 5 is a vertical sectional view of a portion of a slide stopper according to a third embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Main body 2 ... Ink chamber 4 ... Felt tip (pen body) 5 ... Pump mechanism 9 ... Slide stopper 10, 10a, 10b ... Seal part

Claims (5)

[Claims] 1. A cylindrical ink chamber formed in a main body, a pen body axially movably provided at one end of the main body, and a liquid-tight slide in the ink chamber. A slide stopper that is movably provided to partition ink and air filled in the ink chamber, and an internal volume of the ink chamber when the pen body is retracted by writing provided at one end of the main body. And a pump mechanism that pressurizes the ink in the ink chamber to send it to the pen body and retracts the slide plug, and the slide plug has an outer peripheral surface on the inner peripheral surface of the ink chamber. A seal portion made of an elastic material that is in close contact with the ink chamber is formed. The seal portion is in close contact with the inner peripheral surface of the ink chamber. If you apply pressure to the pen, When the retracting stroke of the slide stopper due to the decrease in the internal volume of the ink chamber by the pump mechanism is B, the retracting stroke B when the standard writing pressure is applied to the pen body is the seal width. A writing instrument characterized by being larger than A. 2. The writing instrument according to claim 1, wherein the standard writing pressure is set to 100 grams. 3. The slide resistance of the slide stopper in a stationary state is larger than the load generated when the head pressure of ink corresponding to the length of the ink chamber acts on the slide stopper. The writing instrument according to claim 1. 4. The writing instrument according to claim 1, wherein the pump mechanism is provided with a stopper that restricts a backward stroke of the pen body. 5. A shutoff between the pump mechanism and the ink chamber, which shuts off communication between the ink chamber and the pump chamber when the writing instrument is held in a posture with the pen body facing downward. The writing instrument according to claim 1, wherein a valve mechanism is provided.