Capillary writing medium reservoir system

Details Capillary writing medium reservoir system Capillary writing medium reservoir system

1999-08-09

2001-06-12

Walczak, David J. (Department: 3751)

Coating implements with material supply

Material flows through porous tool

Wick feed from within reservoir to tool

C401S041000, C401S042000

Reexamination Certificate

active

06244774

ABSTRACT:

BACKGROUND OF THE INVENTION
1. Field of the Invention
The inventions relate to a capillary reservoir system for writing medium for writing instruments such as fiber-tip pens, liners and markers, consisting of several individual reservoirs which contain fibrous material. An economical variant according to another proposal contains only one fibrous material reservoir. The invention also relates to a capillary reservoir for colorant—as one of the above-mentioned individual reservoirs—for use in the above-mentioned writing instruments. Finally a process for the production of said colorant reservoir is proposed.
2. Prior Art
Writing instruments are known in a great variety of shapes which contain a liquid writing medium. In such cases the writing medium supply chamber may consist of a refillable supply container or a replaceable cartridge. In the case of fiber-tip pens, a capillary reservoir, e.g. a tampon or a package of fibrous material is provided in the housing of the writing instrument which contains a predetermined supply of ready-to-use writing medium. This supply is assigned to it during manufacture and determines the operating life of the writing instrument (cf. U.S. Pat. No. 3,481,677). When the above-mentioned cartridges are used, then environmental protection problems arise since the waste products—usually plastic cartridges—must be disposed of.
If a built-in writing medium reservoir is provided in the writing instrument which stores a predetermined quantity of writing medium, this quantity is limited a priori. After the previously stored quantity of writing medium has been released the writing instrument is empty and—like the cartridges—must be disposed of. To this one may add the problem that the predetermined quantity of writing medium decreases as a function of age even if the writing instrument is not used, that is to say, when it is on the shelves of the retailers and wholesalers for shipping and sales.
A refillable capillary writing medium reservoir system has become accessible to the technical world from WO 92/18339. It discloses a front and rear reservoir but does not disclose a central individual reservoir which stores the color component contains fibrous material. A “marking or coloring pen” (marker) is described in U.S. Pat. No. 3,993,409 (Hart). In two examples there markers are described which display two individual reservoirs. They are telescoped into one another. One of the reservoirs is the writing tip (or the “writing wick”), the other is the liquid reservoir. The latter is clearly larger than the former. In Hart the individual reservoirs are arranged in one another not on one another, the size dimensions are also contrary to the object of the invention. To be sure the writing wick in Hart also stores the writing fluid and color pigments simultaneously.
U.S. Pat. No. 3,993,409 (Hart) discloses an elongated reservoir having fibrous material filled with a colorant for the production of liquid writing medium which is stored between the fibers, but not a shell permeable for liquid and gasses. Placing a shell around the wick of Hart would be equivalent to making the Hart marker function less which is based on the telescoping—in contact of the outside of the wick and the inner hole (boring) of the plug for its function.
SUMMARY OF THE INVENTION
It is objective of the invention(s) to give the above-mentioned writing instruments a longer operating life and especially a longer shelf life as well as to simplify the production of the reservoir system.
These problems are solved—independently of one another—by the technical ideas taught by the invention.
With respect to the capillary writing medium reservoir system for the above-mentioned writing instrument, the basic feature for the success of the invention is the dividing up of the previously single reservoir into a multiplicity of fibrous material reservoirs. In this case at least three reservoirs are provided, a rear reservoir, a front reservoir, and the individual reservoir between them. The latter stores the color component of the writing medium in dry form in fibrous material. This type of storage is timeless. With it a finished writing instrument can be stored for long periods without drying out and without losing its predetermined writing capacity, because the dry color component of the writing medium cannot dry out further and a liquid component which could escape through the walls or evaporate does not exist. Before the writing instrument is put into use, the rear individual reservoir is impregnated with a dissolving fluid from outside of the writing instrument. It may be water or alcohol. The filled-in dissolving fluid passes from the rear individual reservoir through the wick—connecting the individual reservoirs—to the central fibrous material colorant reservoir where the color component is drawn by capillary forces into the dissolving fluid in order via the wick to reach as a (colored) writing medium the front individual reservoir which is in contact with the writing point. The latter individual reservoir—which may be smaller than the other reservoirs—has the additional function of making the writing medium more uniform and of always storing a certain but limited quantity for immediate writing.
The capillary flow connection is the decisive concept according to the invention, because the consumption of writing medium from the front individual reservoir—due to the forces of equalization extending from the strongly moistened rear individual reservoir to the central individual reservoir—which mixes the colorant in—all the way to the self-emptying front individual reservoir leads to the automatic refilling of the front individual reservoir with writing medium.
The above-mentioned dividing up of the previously single reservoir into a multiplicity of reservoirs—without departing from the idea of the dry reservoir for colorant in a reservoir for coloring material—can be even further simplified in terms of cost. Thus the central and lower individual reservoirs can be brought together to form a continuous reservoir for colorant which stores both the dry colorant (the color pigment) and also—after the writing instrument is filled—the liquid writing medium. In this case only one additional reservoir (the rear individual reservoir) is necessary which is not filled with fibrous material but rather represents a hollow cavity or space. The liquid is poured into this hollow space where it is briefly stored (buffer space) in order to be added slowly to the colorant reservoir. At this time the writing medium is formed which can then be sent to the writing point—which is in connection with the colorant reservoir. While the rear buffer reservoir stores the poured—in dissolving fluid only briefly, i.e. until the writing medium reservoir has totally drawn it out, the latter stores the writing medium in liquid form for a very long time.
If a removable cap is provided for the writing instrument, then it is recommended that its volume be selected so as to be as large as that of the buffer reservoir. But since the colorant reservoir is much larger than the buffer reservoir, manufacture not only becomes less expensive because of the smaller number of reservoirs but the writing instrument thus formed is also provided with a much higher writing capacity A wick is not necessary, since it is not necessary to connect the multiplicity of individual fibrous material reservoirs.
Writing instruments with the capillary writing medium reservoir system described are therefore capable of unlimited storage, do not dry out during such storage and a user can be confident that when the writing instrument is first put into use its full writing capacity will be available—due to the writing medium content in the colorant reservoir.
The last—mentioned colorant reservoir—according to the invention—has an elongated reservoir body. This body is formed of fibrous material. It is surrounded by a shell which is permeable for liquid and gas and which gives the reservoir body its shape and holds it. The liquid writing medium is produced by mixing the color

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