Electrophotography – Internal machine environment – Particle or contaminant control
Reexamination Certificate
2003-02-27
2004-08-24
Chen, Sophia S. (Department: 2852)
Electrophotography
Internal machine environment
Particle or contaminant control
Reexamination Certificate
active
06782220
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a sealing film for toner cartridge ensuring the formation of an opening with a substantially constant width after tearing a central longitudinal portion of said sealing film.
THE PRIOR ART
Up to now many researches have been made in order to find a sealing film for sealing a toner cartridge, which is flexible and which after longitudinal tearing, is suitable for defining an opening with a substantially constant width.
Prestel et al (U.S. Pat. No. 5,110,646) discloses a sealing member not having a preferred tearing direction, which is provided with a series of adjacent perforations. Such perforations cause leakage of toner particles, whereby the use of such sealing member has not be considered as useful by the man skilled in the art.
Films having a preferred tearing linear direction are nowadays used extensively for sealing toner container. However, even with means for lowering the initial tearing force, the opening formed after tearing a central strip is reduced most of the time, some times increased, from the initial tearing end up to the terminal tearing end.
For ensuring a substantially constant width of the opening formed after tearing a central strip from the sealing film, EP-0 788 033 (Canon) has proposed to use a sealing film comprising a base layer having a tearing directionality, a guide layer having a tearing guide portion formed by a laser processing, and a laser barrier layer provided between said base layer and said guide layer. Such a film is expensive and the risk to have an undesired tearing is high as the base layer and barrier layer can induce an undesired tearing.
U.S. Pat. No. 5,523,828 (Canon) discloses a sealing film provided with a flexible tape, a first portion of which attached to the film defines the strip to be torn out, while the other portion of which acts as pulling means. The aim of the first portion of the flexible strip which extends on one surface of the sealing film (i.e. from one free end of the film up to the opposite free end of the film) is to ensure a minimum width of the strip to be torn so as to define an opening or passage for the toner with a minimum width.
Tests made by Applicant have shown that when a film with a tearing directionality is provided with two grooves parallel to the preferred tearing direction, a constant width of the opening formed after tearing the central strip could not be ensured.
It has now been observed that when making cuts or grooves perpendicular to the preferred tearing direction of the film and when tearing the strip in a direction perpendicular to the preferred tearing direction, it was possible to obtain an opening with a substantially constant width.
It has also been observed by Applicant that by selecting the correct material for the sealing member, it was possible to avoid the problem of contamination of the toner with fibrous material.
It has further been observed that when using a too thin film for making an one piece material comprising:
the sealing film provided with cuts or grooves perpendicular to the preferred tearing direction, and
the pulling means,
a risk exists that the pulling means is broken, especially at the place where the pulling means is bent over the sealing film. The present invention has thus for aim to further solve this problem.
SUMMARY OF THE INVENTION
The invention relates to a sealing member for a toner cartridge, said sealing m having a sealing film with a substantially longitudinal portion to be torn out be first end and a second end, said longitudinal portion extending between a first line a second line and to being adapted to be torn between the first end and the second end, wherein said sealing film comprises a layer with a thickness comprised between 20 &mgr;m and 1 mm, whereby said layer is connected to a pulling means, said pulling means comprising at least a layer comprising fibres extending in a direction forming an angle comprised between −60° and +60° advantageously between −45° and +45°, preferably between −15° and +15°, with respect to the tearing direction of the longitudinal portion to be torn.
The fibres of the layer of the pulling means are advantageously substantially parallel to each other, for example welded together.
Preferably, the layer of the pulling means has a portion extending at least partly on the longitudinal portion to be torn out.
According to an embodiment, the sealing film layer has at least one preferred substantially linear tearing direction, said layer being provided with at least:
a first longitudinal surface element selected from the group consisting of cuts, grooves, recesses and combinations thereof and extending along the first line, and
a second longitudinal surface element selected from the group consisting of cuts, grooves, recesses and combinations thereof and extending along the second line,
whereby said longitudinal surface elements extend in a direction of at least 5° with respect to the preferred substantially linear tearing direction.
According to another embodiment,
the substantially longitudinal portion to be torn out is associated to a pulling means having a portion intended to extend at least partly over one face of the film before the tearing of said portion,
whereby at least the portion of the pulling means adjacent to the first end of the portion to be torn out has a sufficient tearing resistance for preventing a separation between the pulling means and the substantially longitudinal portion to be torn out during at least the tearing of the first end of the substantially longitudinal portion of the film to be torn out.
Advantageously, at least the portion of the pulling means intended to extend at least partly over one face of the film before the tearing of the substantially longitudinal portion of the film has a sufficient tearing resistance for preventing a separation between the pulling means and the first end of the substantially longitudinal portion to be torn out during the tearing of the substantially longitudinal portion of the film to be torn out from its first end up to its second end.
According to an embodiment, the substantially longitudinal portion to be torn out is associated to a pulling means having a portion intended to extend at least partly over one face of the film before the tearing of said portion, whereby at least the portion of the pulling means is intended to be bent before the tearing of the substantially longitudinal portion, so that the pulling means extends at least partly over one face of the film before the tearing of the substantially longitudinal portion of the film. The pulling means has a sufficient tearing resistance for preventing a separation between the pulling means and the first end of the substantially longitudinal portion to be torn out during the tearing of the substantially longitudinal portion of the film to be torn out from its first end up to its second end.
According to a preferred embodiment, the pulling means is made in a material having a sufficient tearing resistance for preventing a rupture of the pulling means during the tearing of the substantially longitudinal portion from its first end up to its second end. Such a pulling means is for example a longitudinally oriented film (for example a film having for example a preferred tearing direction perpendicular to the preferred tearing direction of the sealing film), film comprising a mat of fibres, thicker flexible film made of adjacent fibres, for example welded together, films made in a material comprising fibres with a high tearing resistance, film with fibres with a high stretching resistance, fibres laminated with one or more layers, etc.
According to a detail of an embodiment, the sealing film is provided with a means for lowering the initial tearing force. When the sealing film comprises surface elements, the longitudinal surface elements (grooves, recesses, etc.) are preferably associated with a means for lowering the initial tearing force.
Preferably, the surface elements are located on a face of the film intended to be
De Kesel Jan
Sirejacob Gino
Van Betsbrugge Alexander
CF Technologies
Chen Sophia S.
Darby & Darby
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