JPH10236063A - Writing implement - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve the problem of a counterflow mechanism for ink having heavy and large grains with a coloring agent employed, a heavy specific gravity, and a high viscosity by making a specific gravity of a check ball moving in accordance with gravity within a check mechanism smaller than a specific numeric value, and setting it larger several times than the gravity of ink. SOLUTION: A check ball 7 is loosely fitted in the tapered sealing surface of a sealing member 6 being forcibly fixed in the rear inner part of a coupling 3 forcibly inserted in the tip end side of an ink reservoir pipe 8, thereby clogging the ink flow path through close contact and preventing ink from counterflowing. The gravity G of the check ball 7 or a nonspherical check member at the rear end is 11>G>3×W in the specific gravity W of ink held in the inner part, namely, material has the heavier gravity three times than the gravity of ink, and the material does not exceed the gravity 11. Then, the ink viscosity is made 100-20000cp at 23 deg.C, an average grain size of a coloring agent is 0.30-3.0μm, water is contained 50% or more, and the specific gravity of ink containing a 3-40% volatility retardant solvent is made 1.1-2.0.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention has a pen point which is a writing portion, and often causes a problem in a writing instrument or a writing instrument-like container for storing a liquid such as ink directly in an ink storage tube. This is an improvement related to a writing implement having a backflow prevention mechanism for preventing so-called backflow which prevents ink from flowing to the rear end side when not writing or when the pen tip is turned upward, and leaks from an air hole. The present invention relates to an improvement for sufficiently exhibiting a backflow preventing effect and preventing an internal mechanism from being deformed and destroyed during assembly.

[0002]

2. Description of the Related Art Conventionally, in a writing instrument or a container for cosmetics or the like similar to a writing instrument, a liquid such as ink (hereinafter referred to as ink) is absorbed into a fiber bundle called batting, and a pen tip is utilized by utilizing a difference in capillary force. Many mechanisms have been used to derive ink.However, since the remaining amount of ink is large, ink cannot be seen, and the ink flow rate is large at the beginning, there are drawbacks such as thinning with use. Various types of writing implements that have only a mechanism and directly store ink in an ink storage tube have been invented and marketed. However, with this type of direct storage of ink, if the pen tip is stored for an extended period of time, or if it is vibrated, or if it is written upward, ink called backflow leaks from the air hole at the rear end, making writing impossible. It is known that there is a problem of soiling clothes. In order to solve this, some inks have a high viscosity of 5000 cp or more, and a grease-like follower is further provided at the rear end, but these are not fundamental solutions, and a backflow prevention mechanism and Inventions such as a combination of a ball and a valve, and a combination of a spring and a ball to be written (Japanese Utility Model 4-52067, Japanese Utility Model Application Laid-Open No. 6-68887).
4, Japanese Utility Model Application Laid-Open No. Hei 7-28675, and Japanese Patent Laid-Open No. Hei 7-237386). These inventions are already commercially available as products and inventions for their development and improvement.In recent years, gold, silver, and pastel-color inks use particles such as metal powders and inorganic substances and pigment-based colorants having a large specific gravity. Dispersed ink has been developed,
In these inks, it is absolutely necessary to use a relatively large colorant having a particle size of about 0.3 μm to 3 μm in order to secure the color developing properties of the particles. In order to disperse the particles, it is necessary to use an ink having a higher viscosity than other general colors, so that it is difficult to derive the ink, and the specific gravity of the ink increases by 10% to 100% as compared with general colors. If the check ball is made of a material with a low specific gravity, has a nest of air inside, or air adheres to the fine holes on the surface, the check ball takes a long time to move and the tip of the pen tip If the specific gravity of the non-return ball is too large, the reverse flow will be adversely affected during centrifugal defoaming. Mechanism of the channel is non-return mechanism at the time of manufacture with or likely to deform without heat resistance or are brittle chemical resistance or a lack of strength is insufficient has arisen also such problem that is destroyed. If the amount of water vaporized from the pen tip or air hole is large during use, there is a problem that the specific gravity and viscosity are further increased and the check mechanism does not operate effectively. Furthermore, in conventional joints, resin molded parts such as polypropylene, polyacetal, and modified polyphenylene ether are used with an emphasis on suppression of water volatilization, ink resistance, heat resistance, and moldability. Depending on the position of the gate, which will be a filling hole when filling the gate, the gate may be broken from that location, the gate that remains in a protruding shape will damage the ink when inserted, and the ink will leak, or the small gate residue will be scraped off during assembly There is also a problem that the ink is suspended in the ink and becomes clogged in the pen tip portion with writing, thereby making writing impossible.

[0003]

SUMMARY OF THE INVENTION Accordingly, the present invention is mainly aimed at improving a popular writing instrument, and not only solves the problem of ink backflow, but also has the problem of writing property in combination with various inks. In addition, a water-based ink that has recently been marketed, has a lower viscosity than the ink used in ordinary oil-based ballpoint pens, and a medium-viscosity type direct liquid ballpoint pen with a higher viscosity than the batting water-based ink has been launched. However, these inks have a medium viscosity and are easy to move when ink is used, and air easily enters the pen tip due to the shock during storage or movement, and the backflow prevention mechanism has a sufficient function. The problem of causing air to be trapped in the pen tip before it can be used, and the problem of the backflow prevention mechanism with a relatively heavy and high-viscosity ink that uses a heavy and large colorant To provide a writing instrument that does not become a complicated mechanism in consideration of assemblability and performance stability, and that is inexpensive and does not cause backflow or blurring. To solve the problems of ink leakage due to swelling and cracking therein, and to provide a writing implement that does not cause problems in writing performance and backflow prevention performance even when the pen tip is dried.

[0004]

To achieve the above object, there is provided a writing implement or a writing implement-like cosmetic which has a pen tip as a writing section and directly stores a liquid such as ink in an ink storage tube. For this reason, the writing instrument of the present invention has a specific gravity G of a spherical check ball or a non-spherical check piece (hereinafter referred to as a check ball) which is used in a check mechanism and moves in the check mechanism according to gravity. Paying attention to the specific gravity W of the ink, the specific gravity G of the check ball is 11 between each specific gravity where the specific gravity of water is 1.
And larger (heavier) than three times the specific gravity W of the ink. The check mechanism has a groove or a protrusion that can secure a flow path when the check ball is loosely fitted inside the joint and the check ball moves to the pen tip side, and the check ball is provided at the rear end side. In the event of a movement, the ink flow path is blocked by the seal surface in the joint or the seal piece to prevent backflow, or a check ball is loosely fitted in the pen tip to form a seal face at the rear end of the pen tip. The writing ball is springed from the rear with a check mechanism that is narrowed down, or a ballpoint pen-type writing tool that loosely fits the ball that is the writing part of the pen tip between the caulking part at the tip and the receiving seat that has the ink channel behind. A spring tip type that prevents backflow by closing with the crimping inner wall on the tip side and writing ball when writing is not performed by pressing with, or a check ball is not a ball but a front end and an ink flow path is a seal surface at the rear end With a check top Etc. can be used. Furthermore, in the case of inks such as gold and silver, colorants such as metals and inorganic materials, which are slightly larger than ordinary pigments and dyes with an average particle diameter of 0.3 to 3 μm and have a higher specific gravity than the ink, are used in the ink. Therefore, it is necessary to make the ink viscosity of these large and heavy particle inks slightly higher than that of other pigment inks and dye inks, and in these cases, the resistance of the ink flow inside is large. In addition, the specific gravity of the ink is heavier than general ink, and if the movement of the check ball is slow, air will enter from the tip of the pen tip before the backflow prevention mechanism fully operates, affecting the sensitivity of the backflow prevention mechanism Therefore, the configuration of the check mechanism of the present invention is very effective. A non-volatile solvent is used as an auxiliary solvent in the ink to prevent the pen tip from thickening by drying and further increasing the viscosity and the specific gravity. One or more kinds of high-viscosity solvents in total 3
% To 40%. When a joint provided between the tip of the pen tip and the rear end of the ink storage tube is used, the material of the joint can be made of synthetic resin to form the ink flow path and the seal portion of the check mechanism. The position of the molding gate at that time was a joint that was not provided on the press-fitting portion with the ink storage tube, the ink flow path of the check mechanism, or the surface near the check seal surface.

[0005]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 to 3 show a first embodiment of the present invention. As shown in the figure, it is a writing implement for storing ink inside an ink storage tube made of transparent or translucent resin, and is a direct liquid type refill containing aqueous medium viscosity ink. A medium viscosity ink with shear thinning called pseudoplasticity and a grease-like follower that hardly evaporates behind the refill and a PP or P having a specific gravity almost equal to that of the follower so as to float on the follower
A chip that holds a writing ball, which is a writing part, has a built-in follower rod made of resin such as E, and the writing ball is prevented from falling inside by a circumferential caulking part, and the writing ball is freely rotatably loosely fitted. The inside of the pen tip has a flow path necessary for writing. A joint is press-fitted into the tip end of the ink storage tube, and a receiving protrusion having an ink introduction groove having a cross section as shown in FIG. 2 is provided substantially at the center of the inside, and ink is guided to the pen tip by the groove of the receiving protrusion. . A seal piece is press-fitted and fixed to the rear inside of the joint, and a tapered seal surface is formed on the seal piece, and a non-return check fit is loosely fitted in a valve chamber formed between the seal surface and the groove of the receiving projection. During normal writing, the ball communicates with the ball from the ink storage section to the writing section.In the upward direction, the check ball closes to the sealing surface, blocking the ink flow path and preventing ink movement. This is a ballpoint pen having a backflow prevention mechanism with a structure that prevents backflow.

The ink used here is a medium-viscosity ink and a scale-like aluminum powder having a mean particle size of 0.3 to 3 μm when converted into spheres as a colorant such as gold or silver at 23 ° C. Ink viscosity from 100 to 500c at high shear
p, has a shear thinning viscosity of 200 to 20,000 cp at low shear. Common inks have a specific gravity of 1.03 to 1.
Although it is about 2, the specific gravity of gold and silver inks is higher than that of water, and aluminum powder and mica powder having a specific gravity of about 2.5 to 3 are contained in an amount of about 3 to 15% by weight. By being added, the specific gravity of the ink increases. In order to prevent the flow of the ink from causing resistance even in the ink having a relatively high viscosity as a medium ink having a heavy particle and a large particle, the minimum projection sectional area of the flow path of the check mechanism is set to be optimized. Here, the specific gravity of the ink is about 1 for water or a general solvent, and it is difficult to reduce the specific gravity to 1 or less. There is. The check ball sinks according to gravity in the ink, moves backward when it is upward, and closes the ink hole, and when it is downward, it moves forward so that the ink flow path can be secured. Therefore, a specific gravity that is at least heavier than the ink is essential, but in the present invention, a material having a specific gravity greater than three times the specific gravity of the ink and a specific gravity of 1
The material did not exceed 1. Specifically, stainless steel, copper, brass, zirconia ceramic, metal-containing resin, and the like, which vary with the ink but have a specific gravity of 3.3 to 11 and have corrosion resistance to the ink, can be selected. If the specific gravity of the check ball is not sufficient compared to the ink specific gravity (3 times or less of the ink specific gravity), the time required for the check ball to contact the sealing surface and close when the sedimentation speed is slow and upwards And the ink around the check mechanism moves rearward and air enters the pen tip, and then the check mechanism is activated (so-called poor sensitivity). If the specific gravity of the stop ball is too heavy than 11, the centrifugal defoaming during assembling will be 300 when it is larger than 10G.
When a centrifugal force of 0G is applied, the check ball is difficult to move due to the receiving protrusion in the joint, and the receiving protrusion is destroyed. Since the material of the resin is required to be very high in rigidity, it is more advantageous in terms of cost to use a material that does not exceed the specific gravity of the check ball in general writing instruments.

As a second embodiment of the present invention, as shown in FIG. 4, a pen tip has an axially continuous irregular cross-section or a capillary tube such as a fiber bundle, and the outside has a non-permeable resin or metal. The writing point is a pen tip covered with a pen, which is a so-called sign pen or marker that has an ink storage tube behind the pen tip and stores ink directly inside the pen tip. The configuration of the check mechanism is the first embodiment. The effect is the same as that of the first embodiment described above by making it exactly the same as the example. The check mechanism may be a writing implement in which the valve chamber in the joint is decentered so that the check ball does not block the rear end of the pen tip even if the check ball moves forward.

As a third embodiment of the present invention, as shown in FIG. 5, a tip spring for pressing with a load of about 1 g to 40 g is built in, and a circumferential caulking portion serving as a sealing surface with a writing ball is provided. A ball valve mechanism is formed by the writing ball and the writing ball, thereby providing a non-return mechanism having a structure for improving impact resistance, preventing ink volatilization, and preventing reverse flow of ink. This tip spring is usually a spring with a linear portion integrally provided at the tip to directly press a very small writing ball of φ0.3 to φ1.2, and the tip of the tip is used to prevent the tip from coming off. Is secured by caulking. The check ball in this case is a writing ball at the tip,
The effect is exhibited by satisfying the configuration of the present invention. In addition, when a hot-melt type tip sealant 16 that melts at 80 ° C. to 150 ° C. is attached to the tip for the purpose of protecting the pen tip and preventing volatilization during transport, long-term storage is improved and transport to the user is performed. Trouble can be prevented.

As a fourth embodiment of the present invention, as shown in FIG. 6, instead of a check ball, a taper portion for closing a sealing surface is provided at a rear end side, and further, at a pen tip side front side. This is a check frame having a groove or a projection serving as an ink flow path, and has the same effect by satisfying the configuration of the present invention. Further, the injection molding gate of the joint is provided at the outermost outer diameter portion of the outside, and the press-fitting portion with the ink storage tube, the press-fitting portion with the pen tip, and the portion not near the check mechanism are assembled. With regard to the gate at the time, there is no problem such as cracks due to ink leakage, residual stress in the vicinity of the gate, and abnormalities in the sealing surface.

As a specific experimental example, in the case of a combination of a black ink having a specific gravity of 1.1 and a check ball made of aluminum having a specific gravity of 2.58, a time lag occurs in the movement of the check ball and air enters the pen tip. A zirconia ceramic check ball with a specific gravity of 3.5 contains a very small amount of air, but there is no problem in actual use, and stainless steel or copper with a specific gravity of 6.5 or more has no problem. In the case of centrifugal defoaming at the time of manufacture, the receiving projection inside the joint was deformed, and there was a problem in writability. In the case of gold ink having a specific gravity of 1.9, a problem occurred in aluminum and zirconia ceramics, and there was no problem in stainless steel and copper. When the specific gravity of the ink was increased to 2.5, the ink itself was separated during centrifugal defoaming, and the components could not be dispersed.
When the amount of the solvent in the ink is out of the range of the present invention, problems such as thickening of the ink when stored by evaporation of water from the pen tip portion and inability of the ink on the paper surface to dry are caused. In another embodiment (not shown), a joint is not used, a check ball is loosely fitted inside the pen tip, and the rear end of the pen tip is formed radially inward to form a sealing surface over the entire circumference. Inside the joint by removing the check ball, removing the protrusion with the ink introduction groove in the joint as a separate part, or putting out the spring from the pen tip as a push piece of another part without making the straight part of the tip spring The same effect of the present invention can be expected with the writing implement of the embodiment such as the one received in the above.

[0011]

The operation of the present invention will be described in an embodiment. By having a backflow prevention mechanism, it was generally thought that the backflow of the writing instrument could be prevented, but when using various inks in recent years, the specific gravity of the check ball and the ink was sufficiently different. Above, the specific gravity is not so high that it causes problems during centrifugal defoaming of the assembly, which can prevent problems such as delay in the operation of the check mechanism and destruction of parts during manufacturing. . Furthermore, even if there are fine nests inside the check ball or fine bubbles around the check ball, a backflow prevention mechanism that operates stably without being affected by unexpected buoyancy can be provided. Further, by setting the specific gravity of the ink, the viscosity, the particle size of the colorant, and the type and amount of the solvent within the range of the present invention, the operation of the check mechanism is made effective, and the ink has a higher specific gravity due to volatilization of the pen tip. Even if it becomes difficult to do so, it is possible to prevent a delay in the operation of the check mechanism, and furthermore, it is expected that the interaction between them will prevent the occurrence of blur and backflow. In addition, by limiting the gate portion of the joint, a writing instrument free from the influence of the check mechanism and the ink leakage can be obtained at low cost, and an effective writing instrument can be obtained.

[0012]

The construction and operation of the writing instrument according to the present invention are as described above, and have the effect of not causing a serious accident such as backflow that stains clothes. It is possible to provide an easy-to-use writing instrument that can easily use the writing instrument. In addition, there is no problem in manufacturing, and it is possible to use a writing implement that is common to all inks that do not need to combine various parts depending on the ink type. It is possible to provide a stable product with good long-term durability.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing a distal end portion of a writing instrument according to a first embodiment of the present invention.

FIG. 2 is a cross-sectional view showing a check mechanism section AA of the writing instrument according to the first embodiment of the present invention.

FIG. 3 is a longitudinal sectional view showing the entire writing instrument according to the first embodiment of the present invention.

FIG. 4 is a longitudinal sectional view of a tip portion of a writing instrument according to a second embodiment of the present invention.

FIG. 5 is a longitudinal sectional view of a tip portion of a writing instrument according to a third embodiment of the present invention.

FIG. 6 is a longitudinal sectional view of a tip portion of a writing instrument according to a fourth embodiment of the present invention.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 pen tip 2 writing ball 3 joint 4 receiving projection 5 sealing face of seal piece 6 seal piece 7 check ball 8 ink storage tube 9 air hole 10 ink 11 follower 12 follower rod 13 tail plug 14 pen tip caulking portion 15 spring 16 straight portion 17 Back end caulking 18 Check piece 19 Check piece taper section 20 Gate for injection molding

Claims (4)

[Claims] 1. A ball-point pen having an ink storage tube at the back of a pen tip to which a ball serving as a writing portion is rotatably retained and loosely fitted with the ball protruding from the tip, and which stores ink directly inside thereof. In the case where the pen tip is upward or in a non-writing state, the ink flow path is closed to prevent backflow, and the pen tip is in a downward or writing state ahead of the air replacement hole. In the case of having a so-called backflow prevention mechanism that secures an ink flow path for writing, a spherical check ball that is loosely fitted movably inside or a surface that seals the sealing surface at the rear end and the front end side Wherein the specific gravity G of the non-spherical check piece having a groove or a small diameter portion for securing an ink flow path and the specific gravity W of the ink stored therein is 11>G> 3XW. . 2. A writing portion having a pen tip having an irregularly continuous section in the axial direction or a capillary tube made of a fiber bundle or the like and having an outside coated with a non-permeable resin or metal as a writing portion, and an ink storage tube behind the pen tip. In the case of a so-called sign pen or marker that stores ink directly inside the pen, when the pen tip is turned upward or in a non-writing state, the ink flow path is closed to prevent backflow, and the pen tip is It has a so-called backflow prevention mechanism that secures an ink flow path for writing when it is facing down or in a writing state, and has a spherical check ball that is loosely fitted inside so as to be movable inside or a sealing surface on the rear end. The specific gravity G of the non-spherical check top having a groove or a small diameter portion for securing the ink flow path on the front side and the surface closing the ink, and the specific gravity W of the ink stored inside is 1
1>G> 3XW, felt-tip pen, marker type writing implement. 3. An ink viscosity at a typical shear rate of 23
At 100 ° C., the average particle size in terms of spheres as a colorant is from 0.30 μm to 3.0.
μm of an ink in which at least one kind of metal powder such as aluminum or an inorganic substance such as mica is dispersed, the ink contains 50% or more of water as a main solvent, and water such as ethylene glycol, propylene glycol or glycerin. A solvent having a higher viscosity than that of water and a volatilization solvent which is harder to volatilize than water is used as an auxiliary solvent, and at least one or more of them are used in a total of 3% or more and 40% or more.
3. The ink according to claim 1, wherein the ink contains a specific gravity of 1.1 or more and 2.0 or less.
Writing instrument described in. 4. A backflow prevention mechanism, wherein a joint provided between a front end of the writing portion and a rear end of the ink storage tube is made of synthetic resin, and a press-fitting portion with the ink storage tube and an ink flow path of the check mechanism are provided. The writing instrument according to any one of claims 1 to 3, wherein a joint without a molding gate is provided on a surface near the check seal surface.