Coating implements with material supply – Material flows through porous tool – Wick feed from within reservoir to tool
Reexamination Certificate
2000-02-15
2002-01-08
Huson, Gregory (Department: 3751)
Coating implements with material supply
Material flows through porous tool
Wick feed from within reservoir to tool
Reexamination Certificate
active
06336762
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a direct-fluid-supply writing device. More particularly, the present invention relates to a direct-fluid-supply writing device incorporating an ink occuluding member disposed between a pen point and an ink tank and made of a porous material.
Incidentally, it should be noted that “front” is a direction toward the pen point and the “rear” is a direction toward the ink tank.
2. Description of the Related Art
Conventionally, a direct-fluid-supply writing device has been known, which incorporates an ink occuluding member made of a porous material and serving as an ink keeping member for temporarily keeping overflowing ink when the internal pressure of an ink tank has been raised (refer to, for example, JA-B-37-12939U and JP-W-6-510491).
In JA-B-37-12939U, a fountain pen type felt pen has been disclosed, which incorporates a pipe for ink which accommodates an ink reservoir (corresponding to an ink tank according to the present invention); a filled chamber (corresponding to an ink occuluding member according to the present invention) formed in front of the ink reservoir and filled with waste felt or cotton; and a seat plate (corresponding to a partition wall according to the present invention) arranged to partition the filled chamber and the ink reservoir from each other and provided with small apertures (corresponding to communication holes according to the present invention), wherein an elongated felt member (corresponding to an ink inducing member according to the present invention) subjected to a resin process is inserted into the seat plate and the filled chamber.
The direct-fluid-supply writing device disclosed in JA-B-37-12939U is a direct-fluid-supply writing device, in which the ink tank and the pen point are directly connected to each other through the ink inducing member without passage through the ink occuluding member. Therefore, a satisfactory ink discharge characteristic from the pen point can be obtained as compared with a structure that the ink inducing member does not penetrate the ink occuluding member. However, the realized ink discharge characteristic is unsatisfactory in consideration of satisfactorily preventing leakage of ink.
The reason for this will now be described. The sizes of the voids in the capillary structure of the ink occuluding member cannot easily be uniformed in spite of an attempt to uniform the sizes of the voids. Therefore, the sizes of the voids considerably disperse. In particular, voids in the capillary structure having large sizes cannot serve as the temporary ink keeping portions. The existence of the large size voids in the capillary structure causes the overall ink keeping function of the ink occuluding member to deteriorate, causing a problem of ink leakage to easily take place. To effectively form ink keeping portions in the overall body of the ink occuluding member, the sizes of the voids in the capillary structure must previously be reduced (that is, the overall porous structure must have a dense structure).
Therefore, the direct-fluid-supply writing device disclosed in JA-B-37-12939U has small-size voids in the capillary structure of the ink occuluding member to realize a satisfactory ink leakage prevention characteristic. Therefore, ink can reliably be kept in the voids in the capillary structure of the ink occuluding member. On the other hand, air cannot smoothly be introduced into the ink tank, the pressure of which has been reduced. As a result, the ink discharge characteristic from the pen point deteriorates, causing written characters become pale and blurred.
The direct-fluid-supply writing device disclosed in JA-B-37-12939U incorporates the ink occuluding member having uniform capillary attraction. Therefore, when the device is preserved for a long time in a state where the pen point faces downwards, ink is easily concentrated in the front portion of the ink occuluding member. Thus, there is apprehension that ink outwards leaks owing to shock caused when the device is dropped or when the cap is removed. Ink concentrated to the front portion of the ink occuluding member cannot be returned into the ink tank even after the pressure in the ink tank has been reduced owing to consumption of ink. That is, ink is easily accumulated in the front portion of the ink occuluding member. Thus, there is apprehension that ink leaks from the pen point portion.
In JP-W-6-510491, a direct-fluid-supply writing device has been disclosed which has a structure that the capillary supply pipe (corresponding to the ink inducing member according to the present invention) and a capillary solution accumulating container (corresponding to the ink occuluding member according to the present invention) are brought into direct contact with each other. Moreover, the capillary supply pipe is engaged to an opening of a partition wall (corresponding to a partition wall according to the present invention) to close the opening. In addition, the capillary supply pipe engaged to the opening form voids (corresponding to the communication hole according to the present invention) having larger capillary attraction than that of the capillary solution accumulating container to cause an action of exchanging air and ink to be performed.
In general, the communication hole (the void) controls passage of ink and air between the ink tank and the ink occuluding member owing to its sizes (the capillary attraction). Therefore, an excellent dimension accuracy is required to permit communication of air and ink.
If the communication hole has an excessively large size, the capillary attraction is reduced. When the pressure in the ink tank has been reduced, smooth return of ink from the ink occuluding member to the ink tank is inhibited. As a result, outer air is introduced into the ink tank in a state where ink remains in the ink occuluding member. Therefore, the state in the ink tank in which the pressure has been reduced is canceled. When the pressure in the ink tank has been raised, the ink keeping portion cannot sufficiently keep leaked ink. Thus, there is apprehension that ink leaks from the pen point portion.
If the size of the communication hole is too small, the capillary attraction of the communication hole is enlarged. Thus, introduction of air into the ink tank having the reduced pressure is inhibited and, therefore, smooth exchange between ink and air is inhibited. As a result, the reduced-pressure state in the ink tank cannot be canceled. Hence it follows that the quantity of discharged ink from the pen point is gradually reduced from start of consumption of ink. Thus, written characters become pale and blurred.
It can be considered that the communication hole maintains the ink head pressure (density of ink×gravitational acceleration×height from the leading end of the pen point to the communication hole) owing to its capillary attraction. If the capillary attraction is insufficiently small (that is, if the sizes of voids are large), the capillary attraction is insufficient to maintain the ink head pressure. As a result, ink in the front portion of the communication hole moves downwards when the pen point faces downwards. Thus, there is apprehension that ink leaks from the pen point.
Therefore, the direct-fluid-supply writing device disclosed in JP-W-6-510491 and incorporating the ink inducing member made of the porous material, such as fibers, encounters great dispersion of sizes of the plural voids in the ink inducing member. Thus, the largest void serves as the communication hole according to the present invention which permit air blow.
To make the size of the largest void serving as the communication hole to be small so as to prevent the problem of leakage of ink from the pen point portion caused from retention of ink in the ink occuluding member, the sizes of the voids in the capillary structure of the ink inducing member in the opened portion must considerably be reduced in consideration of dispersion of the sizes of the voids. As a result, the capillary attraction of
DeVore Peter
Huson Gregory
The Pilot Ink Co., Ltd.
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