Incremental printing of symbolic information – Ink jet – Fluid or fluid source handling means
Reexamination Certificate
2001-12-31
2004-02-17
Vo, Anh T. N. (Department: 2861)
Incremental printing of symbolic information
Ink jet
Fluid or fluid source handling means
Reexamination Certificate
active
06692118
ABSTRACT:
BACKGROUND OF THE INVENTION
This invention relates to a pierceable sealing element for a liquid outlet, especially the ink outlet opening of an ink reservoir in inkjet printing means, which has a piercing area which can be pierced by a hollow needle for removing liquid, and the hollow needle can be surrounded sealed from the outside by the pierced seal element. An ink reservoir for detachable mounting in inkjet printing means with an ink outlet opening which is sealed by one such pierceable sealing element is likewise the subject matter of the invention.
To remove liquid as necessary, for example from an ink reservoir, sealing liquid-tight the outlet or removal opening with a closed sealing element which is intact before use is known. The liquid can be removed by means of a hollow needle which is plunged from the outside into the filled reservoir interior through the piercing area of the sealing element intended for this purpose. These sealing elements are used preferably in inkjet printing systems where the interchangeable ink reservoirs, the so-called ink cartridges, are first sealed on their ink outlet opening with one such pierceable sealing element after filling with ink during manufacture. The inkjet printer has a corresponding hollow needle which pierces the sealing element when the ink cartridge is being used and the ink contained in the ink cartridge can be supplied to the print head.
The important advantage of a pierceable sealing element is that it is sealed tight before the first use, i.e. the first perforation by the hollow needle, so that the liquid contained in the reservoir can neither emerge uncontrolled from the liquid outlet nor evaporate. Especially in ink cartridges is this particularly important since after production and filling with ink in general they are only used after some time. Even when stored for a longer time it must be ensured that neither the ink fill level is reduced nor the consistency of the ink adversely changed by vaporization.
One possibility for implementing a pierceable sealing element consists in the attachment of a liquid-tight and vapor-tight sealing film from the outside on the outlet opening. So that it can be easily pierced, i.e. clears the outlet when the generally relatively blunt hollow needle is plunged through, this sealing film consists of thin, relatively poorly elastic plastic material. In this way, when the piercing area is punctured it is completely ruptured and clears the outlet cross section. One such sealing film however does not perform a sealing function so that in the sealing element there must be additional sealing rings which seal against the outside periphery of the hollow needle so that liquid cannot emerge there uncontrolled along the hollow needle. These arrangements, as are described for example in EP 1 000 753 A1, are relatively complex due to the separate sealing elements.
A less complex version of a pierceable seal is a so-called septum. It has a relatively thick piercing area of rubber or thermoplastic elastomer. This piercing area bursts when the hollow needle is inserted, not over its entire surface in an uncontrolled manner, like a sealing film, but is essentially penetrated only in the cross sectional area of the hollow needle. Due to the elasticity of the rubber or elastomer material, the boundary surface of the puncture channel formed in doing so is pressed against the outside periphery of the hollow needle so that a certain sealing is achieved without additional sealing elements. Moreover when the hollow needle is removed the puncture channel is automatically reclosed. But when examined minutely, it is found that when the hollow needle punctures, the material of the septum is not radially displaced in a uniform manner, but a small lengthwise tear forms. In the area of the ends of the tear however along the puncture channel between the material of the septum and the outside periphery of the hollow needle gusset-like passages are formed. For this reason leaks are inevitable, especially when there is liquid in the container for a longer time, on the septum, as is the case in an inkjet printing systems. Likewise attempts have already been made to mold a piercing area with a reduced material thickness into the septum. But the results are however likewise not completely satisfactory since the seal can likewise be adversely affected by the irregular tear edges in the penetration channel.
In view of the aforementioned problems in the prior art, the motivation for the invention is to make available a pierceable sealing arrangement and an ink reservoir with one such sealing arrangement which has improved functionality with respect to the indicated problems. In particular, sealing to the hollow needle which is improved compared to a septum will be achieved and the production and installation cost will be as low as possible, especially less than in a multi-part arrangement with seals and a separate sealing film.
To solve the aforementioned problem as claimed in the invention an ink reservoir with a pierceable sealing element and a pierceable sealing element of the initially mentioned type are proposed in which the piercing area is surrounded by an annularly peripheral sealing profile which can be twisted in the manner of a torus at least partially around a peripheral line when the piercing area has been pierced, a sealing surface which runs radially on the inside being formed.
SUMMARY OF THE INVENTION
As claimed in the invention a novel sealing element is made available which has clearly distinguishable operating areas in one component. One particular feature compared to the prior art consists in that the two functions, specifically on the one hand the sealing function by a piercing area which can be ripped open only if necessary and on the other hand the sealing function with respect to the hollow needle in the penetrated state, are implemented by a functionally connected arrangement of the central piercing area with a special sealing profile which is formed or activated only when pierced.
In the initial state, before the sealing element has been pierced by a hollow needle, the piercing area extends for example in the form of a thin membrane over the opening cross section of an annular sealing profile which is inserted for its part tightly into the outlet opening, for example the ink outlet opening of an ink cartridge for an inkjet printing means. If from the outside a hollow needle is plunged into the piercing area, it tears or bursts so that the liquid outlet is cleared for example for ink removal through the hollow needle.
As was detailed initially, it can be assumed that the piercing channel or the tear edges of the piercing area at best provide for unsatisfactory sealing of the hollow needle in the outlet opening. The special advantage of the invention at this point consists in that when the piercing area is ripped open and with the associated radial bending-up of the separate parts of the piercing area which are connected in their outer edge areas to the sealing profile which runs peripherally there, the sealing profile is cleared and activated for sealing of the hollow needle. To do this, the sealing profile as claimed in the invention is actively manipulated by its being ripped open, i.e. the piercing of the piercing area, such that it is twisted toroidally on its inner periphery in the puncture direction of the hollow needle, i.e. that the surface areas of the sealing profile which are outside with respect to the puncture direction are swivelling radially to the inside in the direction of the pierced opening in an arc-shaped swivelling motion. In this way the actuation or formation of the sealing profile takes place such that annular surface areas of the sealing profile which are initially farther to the outside are swivelled to the inside, by which a defined sealing surface which runs radially to the inside is formed. This surface can uniformly adjoin the surface of the inserted hollow needle over the periphery. Because this sealing surface is a defined surface area which is uniformly smooth espe
Busch Peter
Klein Dirk
Michele Helmut
Artech GmbH Design + Production in Plastic
Hoffman Wasson & Gitler PC
Vo Anh T. N.
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