Incremental printing of symbolic information – Ink jet – Fluid or fluid source handling means
Reexamination Certificate
2001-02-12
2002-07-23
Vo, Anh T. N. (Department: 2861)
Incremental printing of symbolic information
Ink jet
Fluid or fluid source handling means
C347S093000
Reexamination Certificate
active
06422692
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to an ink cartridge for use with an ink jet printer or the like.
2. Prior Art
An ink cartridge IC for holding a dye-based ink, shown in
FIGS. 17A and 17B
, for instance, includes an ink reservoir (so-called ink tank) filled with an ink absorbent material FA, and an ink delivery block,
26
formed in a bottom of the cartridge in a manner protruding downward therefrom. The ink delivery block
26
is formed with a communication passage
27
extending therethrough into the ink reservoir, and holds an ink absorbent material FB (ink filter) at an inner portion of the communication passage
27
. In the above construction, the ink cartridge IC is formed to have a rectangular inner shape so as to hold a larger amount of ink in a space limited in size and at the same time make the cartridge easy to manufacture (mold in one piece). Further, to make the whole ink cartridge compact in size by reducing the size of the protruding block formed in the bottom, the partition wall defining the communication passage
27
is extended into the inner space of the ink reservoir and the ink absorbent material FB is retained inside the inner peripheral surface of the partition wall.
In contrast to the dye-based ink having a coloring matter solved therein, a pigment-based ink contains an insoluble coloring matter (pigment) having a large particle size. Therefore, the pigment-based ink is excellent in light resistance when illuminated after printing, and difficult to fade. On the other hand, the coloring matter (pigment) of the pigment-based ink is dispersed in the ink with particles thereof floating therein, and hence liable to settle out or sediment with the lapse of time. (Although some inks generally classified into “the dye-based ink” contain a coloring matter which settles out, throughout the specification and appended claims, the term “pigment-based ink” is used to mean “an ink whose coloring matter settles out” including the above-mentioned exceptional type of dye-based ink.) Accordingly, when the ink cartridge IC for holding a dye-based ink, described above with reference to
FIGS. 17A and 17B
, is used for holding a pigment-based ink, sedimentation of the ink proceeds especially in regions filled with ink alone (ink-filled regions) DIa, DIb, to produce an ink having a high coloring matter concentration (i.e. a portion of the above pigment-based ink, which is increased in coloring matter concentration by sedimentation of the coloring matter: hereinafter referred to as “sedimentary ink”). The sedimentary ink irregularly flows out during printing to cause unevenness of printing such that the printing is carried out e.g. with a high print density immediately after the start of printing, but with a lowered print density thereafter.
SUMMARY OF THE INVENTION
It is a first object of the invention to provide an ink cartridge that is capable of supplying a pigment-based ink and at the same time suppressing the mixing of a sedimentary ink into a pigment-based ink supplied, thereby reducing unevenness of printing.
It is a second object of the invention to provide an ink cartridge that is capable of supplying a pigment-based ink and at the same time suppressing the generation of a sedimentary ink even when left unused, thereby reducing unevenness of printing.
It is a third object of the invention to provide an ink cartridge that is capable of supplying a pigment-based ink and at the same time removing a sedimentary ink by initial delivery of the ink after the cartridge is left unused, thereby reducing unevenness of printing.
To attain the first object, according to a second aspect of the invention, there is provided an ink cartridge comprising:
an ink reservoir holding an ink absorbent material therein for storage of a pigment-based ink;
an ink delivery block formed at a lower portion of the ink reservoir, and having a communication passage formed therethrough such that the communication passage extends from an outside of the ink reservoir up to an inner opening of the communication passage which opens into an inside of the ink reservoir, for communication between the outside and the inside of the ink reservoir; and
a sedimentary ink supply-suppressing member for suppressing flow of a sedimentary ink to the inner opening, the sedimentary ink having an increased coloring matter concentration caused by sedimentation of a coloring matter floating in the pigment-based ink.
This ink cartridge includes an ink reservoir holding an ink absorbent material therein for storage of a pigment-based ink, and an ink delivery block formed with a communication passage for communicating between the inside and outside of the ink reservoir. The ink cartridge has the same basic construction as that of the conventional ink cartridge, and when the ink cartridge is left unused, a sedimentary ink is produced. If the ink is delivered as it is, the sedimentary ink is mixed into the ink (pigment-based ink), thereby causing unevenness of printing. Therefore, in order to suppress the mixing of a sedimentary ink into the supplied ink, the ink cartridge has a sedimentary ink supply-suppressing member that prevents flow of a sedimentary ink to the inner opening. This makes it possible to provide an ink cartridge that is capable of supplying a pigment-based ink, and at the same time suppressing the mixing of a sedimentary ink into the supplied pigment-based ink, thereby reducing unevenness of printing.
Preferably, the pigment-based ink is supplied by being drawn in by a predetermined suction force, and the inner opening is arranged above a lowermost bottom surface inside the ink reservoir, the sedimentary ink supply-suppressing member comprising another ink absorbent material different from the ink absorbent material, the another ink absorbent material having an ink-holding force larger than the predetermined suction force, and being arranged in a bottom portion of the ink reservoir at a location lower than the inner opening.
According to this preferred embodiment, while the pigment-based ink is supplied by being drawn in by a predetermined suction force, the inner opening is arranged above the lowermost bottom surface inside the ink reservoir, and hence a sedimentary ink is liable to be generated in a bottom portion of the ink reservoir lower than the inner opening. To cope with this, the ink absorbent material having an ink-holding force larger than the predetermined suction force for supply of the ink is arranged in the bottom portion of the ink reservoir lower than the inner opening, whereby it is possible to hold the sedimentary ink from being delivered as part of the pigment-based ink. This makes it possible to provide an ink cartridge that is capable of supplying a pigment-based ink, and at the same time suppressing the mixing of a sedimentary ink into the supplied pigment-based ink, thereby reducing unevenness of printing.
Alternatively, the inner opening is arranged above a lowermost bottom surface inside the ink reservoir, and the sedimentary ink supply-suppressing member comprises a sedimentary ink receiving member arranged in a bottom portion of the ink reservoir below the inner opening, for receiving the sedimentary ink.
According to this preferred embodiment, the inner opening is arranged above the lowermost bottom surface inside the ink reservoir, and hence a sedimentary ink is liable to be generated in a bottom portion of the ink reservoir lower than the inner opening. To cope with this, a sedimentary ink receiving member is arranged in the bottom portion of the ink reservoir lower than the inner opening for receiving the sedimentary ink, whereby it is possible to hold the sedimentary ink from being delivered as part of the pigment-based ink. This makes it possible to provide an ink cartridge that is capable of supplying a pigment-based ink, and at the same time suppressing the mixing of a sedimentary ink into the pigment-based ink supplied, thereby reducing unevenness of printing.
Alternatively, the sedimentary ink supply-suppressing member compris
Ogawa Ayao
Yamazaki Atsushi
Hogan & Hartson L.L.P.
Seiko Epson Corporation
Vo Anh T. N.
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