Coating implements with material supply – Bifurcate pointed nib tool – Including reservoir and feeder
Reexamination Certificate
2001-05-24
2002-11-05
Eloshway, Charles R. (Department: 3751)
Coating implements with material supply
Bifurcate pointed nib tool
Including reservoir and feeder
C401S205000
Reexamination Certificate
active
06474895
ABSTRACT:
1. Technical Field
The present invention relates to a writing instrument for controlling ink supply to a writing element, and more particularly to a writing instrument and method of producing the same for controlling the ink supply by a gas enclosed in a blocking chamber with a small volume which has the gas such as air enclosed therein, and which is provided inside an ink supplying passage extending from an ink chamber to the writing element.
2. Background Art
In general, in a writing instrument of the type storing liquid ink in an ink chamber, it is necessary to control a flow amount and pressure of the ink being supplied from the ink chamber to a writing element. As the simplest type of such an ink control, there is a method for providing a porous member referred to as a relay core made of a bundle of fibers between an ink chamber and writing element, while pulling the ink out of the ink chamber by the capillary force of the relay core, and controlling a supply amount of ink by the resistance received by the ink flowing inside the relay core.
In addition, the capillary force exists in a writing element due to fine gaps between fibers when the writing element forms a so-called felt chip made of a bundle of fibers, or due to a fine gap between a ball and a ball holder when the writing element forms a ball chip. Such a capillary force causes the writing element to have an ink pulling force for pulling the ink and an ink holding force for holding the pulled ink.
Therefore, the above-mentioned control only by the relay core has not been able to stabilize the ink supply. That is, if the density of the relay core is reduced to decrease the flow resistance of the ink, when the writing instrument is not used for writing, the ink in the ink chamber is pulled out of the chamber by the ink pulling force of the writing element described above, and the writing element contains a large amount of the ink to be saturated, and becomes so-called ink rich state. As a result, a disadvantage arises that writing becomes undesirably thick at the beginning of the writing. Particularly in a ball chip using water-soluble ink, the ink pulling force and ink holding force have the hydraulic pressure head of only the order of a few ten to a hundred mm. Therefore, in a condition that this writing instrument is allowed to stand, i.e., that the ball chip is directed downward, it sometimes happens that a small amount of ink is pushed out of the gap between the ball and ball holder, due to the hydraulic pressure head of the ink existing in a portion from the ink chamber to the ball chip. When writing is started in such a condition, a disadvantage arises that a starting portion of the writing line becomes a shape of a comma (,).
In order to avoid the disadvantage, it is required to increase the density of the relay core to increase the capillary force and inner flow resistance, however, thus increasing causes the ink flowing inside the relay body to receive an excessive flow resistance. Hence, in the case of writing fast or the like, the supply of ink is insufficient, and a condition, so-called ink poor condition, occurs that an ink amount contained in the writing element is too small. As a result, a disadvantage may occur such that the writing becomes blurred.
In order to avoid the disadvantage, various ink control mechanisms have been considered conventionally. One of the mechanisms is to provide between an ink chamber and writing element a small mechanical valve mechanism that is opened by a predetermined pressure difference. In this mechanism, the valve mechanism is closed at the time the writing instrument is not used for writing, and thereby the ink is prevented from being supplied excessively to the writing element. Then, at the time the instrument is used for writing, the valve mechanism is opened due to a pressure difference caused by the ink pulling force of the writing element, and thereby the ink is supplied from the ink chamber to the writing element.
However, the above-mentioned valve mechanism is required to operate to be opened or closed by a small pressure difference of the hydraulic pressure head of the order of a few ten mm, and is further required to be formed to extremely small, and therefore has a disadvantage that the production, quality control and the like thereof become complicated. Further, in the case where the writing element forms the ball chip using water-soluble ink described previously, since the ink pulling force is low, the pressure for opening or closing such a valve mechanism should be set extremely finely, and thereby a disadvantage occurs that the production, quality control and the like thereof become complicated.
Further, as another ink control type, there is a so-called air chamber type in which a small chamber with air enclosed therein is provided between an ink chamber and a writing element. In general, when air exists in a liquid passage with a small cross-sectional area, a phenomenon, so-called vapor lock, occurs that the air becomes bubbles, thereby blockades the passage and blocks the flow of the liquid. The air chamber type uses the principle of this phenomenon to configure a kind of valve mechanism.
The air chamber type of instrument does not essentially require a mechanically movable portion such as a valve, and has advantages that the structure is simple and that the production is easy. However, the air chamber type of instrument naturally requires a mechanism for flowing the ink blocked by the internal bubbles at the time of writing, and therefore provides a problem that it is difficult to reserve the stability of the operation in the mechanism.
An example of the air chamber type of writing instrument is disclosed in U.S. Pat. No.3,397,939. In the writing instrument, a small chamber with air enclosed therein is formed in an ink passage provided between an ink chamber and a writing element, is opened in its upper portion into a passage which communicates with the ink chamber, and is filled in its lower portion with a porous filler which communicates with the side of the writing element.
In the instrument of the USP, when the instrument is not used for writing, the porous filler contains the ink to be almost saturated, and the air enclosed in the small chamber blocks the flow of ink. Then, when the ink contained in the filler is consumed by the writing and the porous filler becomes the ink poor condition, the air inside the small chamber is absorbed into the porous filler. Since the air inside the small chamber is thus absorbed into the filler, the ink flows into the small chamber from the above-mentioned passage, and is absorbed into the filler. Then, when the filler with the ink absorbed therein becomes the ink rich condition, the air absorbed into the filler is released to the small chamber to block the flow-in of the ink.
The instrument disclosed in the USP does not have a mechanically movable portion, has a simple structure, and is capable of controlling the flow of ink assuredly even when the ink pulling force of the writing element is low. However, a case sometimes occurs that the whole amount of air absorbed into the porous filler is not released when the ink is newly absorbed into the filler. Then, the air remaining in the filler flows as the ink in the filler flows by writing, and when the remaining air reaches the writing element, the ink pulling force of the writing element is decreased, and the writing becomes impossible or has an inconvenience.
In order to avoid the above-mentioned disadvantage, the instrument of the USP is configured so that the upper portion of the small chamber is formed in the shape of a cone, and that when the ink flows into the chamber from the passage communicating with the ink chamber, the ink drops along the inner periphery of the small chamber to be absorbed in the periphery of the filler filled in the lower portion of the small chamber. By such a configuration, the ink penetrates from the periphery to the center portion of the filler, and thereby the air absorbed in the filler collects towards the center portion to be
Eloshway Charles R.
HICS Corporation
Jones Day Reavis & Pogue
LandOfFree
Writing instrument and method of producing the same does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Writing instrument and method of producing the same, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Writing instrument and method of producing the same will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2944903