Coating implements with material supply – Material flows through porous tool – Wick feed from within reservoir to tool
Reexamination Certificate
2002-12-04
2004-07-13
Huson, Gregory L. (Department: 3751)
Coating implements with material supply
Material flows through porous tool
Wick feed from within reservoir to tool
Reexamination Certificate
active
06761496
ABSTRACT:
TECHNICAL FIELD
The present invention relates to a writing instrument having a structure in which inhibition of vaporization of an ink solvent is incomplete, which is equipped with an exchangeable inner pen (refill) filled with an ink which has a pen tip comprising a fiber feeder or a plastic feeder, particularly to a writing instrument suited to a marking pen, a white board marker and a felt-tip pen.
BACKGROUND ART
A large variety of writing instruments of a refill type has so far been put to practical use for ballpoint pens. In ballpoint pens, inks contain solvents having a low vapor pressure and have a high viscosity, and therefore the inks are less liable to volatilize. Further, the ballpoint pens have a structure in which a refill is less degraded and the refill can be exchanged.
In contrast with this, in markers called marking pens as a common name in which a pen tip comprises a fiber feeder comprising a fiber bundle or a plastic feeder, the following problem is present when markers of a refill type are put to practical use (actualize).
That is, as a principle, use of a solvent having a low vapor pressure (less liable to volatize) makes it possible to actualize marking pens of a refill type requiring no cap or having a structure in which a refill is incompletely sealed, but they have the problem that a drawn line-drying property which is a characteristic of a marking pen is damaged, so that the drawn lines are less liable to be dried.
When a solvent having a high vapor pressure (liable to volatize) is used, the drawn line-drying property is good, but if a writing instrument main body (external structure) in which a refill is mounted is not provided with a structure for sufficiently inhibiting a solvent from vaporizing, generated is a problem that a viscosity of an ink (particularly, a surface and an inside of a pen feeder) is elevated due to volatilization of the solvent, which makes writing impossible.
Known as a writing instrument in which a writing instrument main body is provided with a structure for preventing a solvent from vaporizing are, for example, a knock type writing instrument
44
as shown in FIGS.
4
(
a
) and (
b
), in which a cap part
42
for a housing room
41
for housing a pen tip
40
covers the room when the pen tip is drawn in by a string member
43
to be movable with knocking operation (U.S. Pat. No. 2,579,188, Japanese Patent Application Laid-Open No. 81094/1998, Japanese Patent Application Laid-Open No. 81095/1998 and Japanese Patent Application Laid-Open No. 242094/1995), a knock type writing instrument
49
as shown in FIGS.
5
(
a
) and (
b
), in which a housing room
48
for preventing a pen tip
46
from drying is provided in a writing instrument main body
45
which is covered by a rubber member
47
having a slit
47
a
(Japanese Utility Model Application Laid-Open No. 95288/1991) and a knock type writing instrument
54
as shown in FIGS.
6
(
a
) and (
b
), in which a sealing member
53
having a slit
53
a
for preventing a pen tip
52
from drying is provided in a front barrel
51
of a writing instrument main body
50
(Japanese Utility Model Application Laid-Open No. 76778/1983). It is considered that writing instruments provided with sealing structures having these dry-preventing mechanisms can solve the problems described above, but if they are provided with both of a sealing structure and a structure which enables refilling, the structure is complicated more and more, and the product becomes more expensive. In addition thereto, it becomes more difficult to secure the sealing property. Further, a problem resides in that a simple structure using an elastic body shown in
FIGS. 5 and 6
not only makes the initial performance imperfect but also makes it impossible to secure sufficient sealing due to deterioration of the elastic body with passage of time to cause inferior writing.
On the other hand, the followings have so far been carried out in order to obtain writing instruments such as marking pens, felt-tip pens and writing brush pens which are excellent in a cap-off performance for inhibiting pen tips from drying; that is, higher fatty acid esters of polyglycerin are added to inks (Japanese Patent Publication No. 34352/1987); paraffin waxes which can be deposited on the surface of a pen tip to form a thin film are added to inks (Japanese Patent Publication No. 35028/1989); hexaglyceryl tristearate is added to inks (Japanese Patent Application Laid-Open No. 232277/1990); and lecithin is added to inks (U.S. Pat. No. 2,594,457).
However, additives having a high vaporization-inhibiting effect have a low solubility (10% by weight or less) in solvents in many cases, and a problem resides in the fact that the solubility is low, particularly that the solubility at 0° C. is very low (5% by weight or less). Involved therein is the problem that depositions of the additives described above are produced in the inks during storing at a low temperature or in repeating of low and high temperatures to cause clogging in the ink passages, whereby the writing property is reduced or the cap-off performance is deteriorated with the passage of time, and thus the effective vaporization-inhibiting effect has not yet been obtained.
On the other hand, disclosed in Japanese Patent Application Laid-Open No. 242094/1995 is a method of preventing drying for a writing instrument characterized by that in order to effectively inhibit vaporization of an ink solvent from a writing part during a period passing until initial writing after producing a writing instrument and to prevent it in a state not to be used over a long period of time from producing a cause of inferior writing, a high boiling solvent such as benzyl alcohol having a low volatilizing velocity out of ink solvents is in advance coated on or impregnated into the writing part of the writing feeder described below in a writing instrument in which one end part of a writing feeder prepared from a porous feeder material is inserted into an ink reservoir occuluding an ink prepared by dissolving a dye in a solvent and in which the other end part forms a writing part.
However, in the method of preventing drying for a writing instrument disclosed in this official gazette, an object thereof is to prevent drying during a period passing until initial writing after producing a writing instrument, and used is a high boiling solvent such as benzyl alcohol having a low volatilizing velocity out of ink solvents. Accordingly, it is not intended to prevent the writing part from drying after writing.
That is, a problem resides in that benzyl alcohol is liquid at room temperature and arbitrarily miscible with solvents so that it is occluded into an ink reservoir by virtue of diffusion of the solution to almost lose effect, if the pens are left standing over a long period of time. Further, benzyl alcohol flows out in writing once and therefore does not maintain the effect until the ink is exhausted.
As described above, the current situation is that in writing instruments such as marking pens, felt-tip pens and writing brush pens having pen tips comprising conventional fiber feeders or plastic feeders, the pen tips have not yet been sufficiently inhibited from drying, and the circumstance is that markers such as marking pens of a refill type have not been able to be provided as yet.
In light of the problems on the conventional techniques described above, the present invention intends to solve them, and an object thereof is to provide a writing instrument equipped with an exchangeable inner pen (refill) filled with an ink which has a pen tip comprising a fiber feeder or a plastic feeder, wherein it is excellent in inhibition of vaporization of an ink solvent from a pen tip; even if the writing instrument main body has a structure in which inhibition of vaporization of the ink solvent is insufficient or particularly the writing instrument does not have a cap member, the inner pen (refill) is less deteriorated and exchangeable; and it well adapts to an environmental issues such as the best utilization of the resources and ca
Ami Kazuhiro
Osada Takahiro
Sawa Yukinori
Burns Doane Swecker & Mathis L.L.P.
Huson Gregory L.
Le Huyen
Mitsubishi Pencil Kabushiki Kaisha
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