Incremental printing of symbolic information – Ink jet – Fluid or fluid source handling means
Reexamination Certificate
2000-08-16
2002-07-02
Vo, Anh T. N. (Department: 2861)
Incremental printing of symbolic information
Ink jet
Fluid or fluid source handling means
Reexamination Certificate
active
06412932
ABSTRACT:
FIELD OF THE INVENTION AND RELATED ART
The present invention relates to an ink container, in which fiber is placed as an ink retaining member for retaining ink, an ink jet apparatus employing such an ink container, and a manufacturing method for such an ink container.
As for a conventional ink container (whether it is integrated with a recording head, or it is exchangeable independently from the head) having been put to practical use for ink-based recording, there is a type of ink container filled with a single or a plurality of sponge pieces.
The sponge piece is placed in the ink container to prevent the ink from leaking out of a liquid ejecting portion such as a nozzle provided in a recording means. More,specifically, it is placed there to use the capillary force peculiar to porous material such as sponge; the capillary force is used as back pressure for impeding the ink low directed toward the recording means. This back pressure creates negative pressure, relative to the atmospheric pressure, in the ejecting portion, and hereinafter, it will be referred to as “negative pressure”.
Generally speaking the diameter of a sponge pore falls within a range of 80-200 &mgr;m, and the sponge material itself occupies a substantial portion of the internal volume of the container. Therefore, as long as the sponge is present within the ink container, little can be expected from an attempt made to increase the amount of the ink, relative to the internal volume of a given ink container, that is, an attempt made to improve the space usage efficiency for the ink container.
Further, even when an effort is made to modify the structure of the ink container so that the amount of the ink, which otherwise ends up being left unused in the ink container, is reduced, the capillary force or the like of the sponge places an inherent limit to the reduction.
The porous material employed as the ink retaining member is formed in advance in a predetermined shape; therefore, when it is compressed into the ink container, the contour of the porous material does not perfectly conform to the internal surface of the ink container, leaving gaps between the two, which is liable to fail to create the capillary force expected there. Further, urethane form, a typical porous material, is not compatible with certain types of ink, which limits the number of ink choices to be stored in the ink container.
Therefore, the inventors of the present invention made a proposal in a Japanese Laid-Open Patent Application No. 34353/1990 in which the ink supplying efficiency was improved by rendering smaller the sponge pore diameter adjacent to the ink supplying port than in the middle of the ink container. The inventors of the present invention disclosed another invention in a Japanese Laid-Open Patent Application No. 8405/1993, in which a bundle off parallelly bound straight strands of fiber was disposed next to the ink supplying port, which was effective for improving the ink supplying efficiency and reducing the amount of the unusable ink.
There are fiber-based structures other than those described above: for example, the structures disclosed in Japanese Laid-Open Patent Application Nos. 96742/1993 and 104735/1993, in which the direction of the ink movement was changed. In the former invention, a bundle of fiber strands is disposed in contact with the sponge piece, in such a manner than when the ink container is in use, the bundle of fiber strands extends from the bottommost portion to the ink supply port disposed above, whereby the amount of the unusable ink which otherwise ends up remaining in the bottom portion of the ink container is reduced. In the latter invention, the entire internal space of the ink container is filled with sponge, and a bundle of fiber strands is disposed within a portion projecting from the ink container, wherein this bundle of fiber strands constitutes an ink supply passage for supplying the ink to the sponge disposed adjacent to the filter of a recording head.
As described above, the main stream inventions regarding the internal structure of an ink container presumes the presence of the sponge; therefore, they have not reduced substantially the amount of the ink retained unusably in the sponge or have not solved the problem that the ink capacity of the ink container is reduced by the presence of the sponge.
On the other hand, a Japanese Laid-Open Patent Application No. 79882/1994 (Corresponding to European Appln. 562,733) discloses a structure in which strands of fiber extending vertically (in the direction of the gravity) are disposed within the ink container to occupy no more than 20% of the internal space of the container so that the ink capacity of the ink container is substantially increased, and also, the ink supplying efficiency is improved. However, in this invention, only a small amount of straight fiber, or the strands of fiber, are arranged merely in one direction.
This Laid-Open Patent Application No. 79882/1994 also discloses a modification, in which nonwoven fabric of polyester, polypropylene, or the like is filled in layers in the ink container. This modification is not different from the original in that it suffers from the problems of the conventional ink container.
Through extensive studies of the inventions described in the foregoing, the inventors of the present invention discovered that the structures disclosed in these inventions barely provided an ink retaining capability, and the strands of fiber collected together in a manner of being bundled as the ink was filled. As a result, the ink was concentrated around the ink supply port, deteriorating the efficiency with which the ink was fed out of the ink container, and also, it was impossible to create stably the negative pressure, which was an important factor in the field of ink jet recording.
SUMMARY OF THE INVENTION
The primary object of the present invention is to solve new problems, that is, the insufficient ink delivery, the ink leak, and the like, which are created due to the reduction in the overall ink retaining capability of an ink container, resulting from the decrease of the intervals among the strands of fiber employed as the ink retaining material, which occurs while the ink is filled.
Another object of the present invention is to provide an ink container in which the ink retaining capacity is increased by means of improving the arrangement of the fiber that occupies the internal space of the ink container, wherein this fiber strand arrangement relates to the way the fiber strands contact the internal walls of the ink container, and the way the fiber strands contact each other.
During the making of the present invention, attention was given to a different view point: there is an ink flowability difference between the inner portion of the ink container and the portion next to the container wall. In other words, the relationship between the ink flowability, and the material for the ink container internal wall and fiber strand, which had not been studied formerly, was studied. As a result, the present invention could provide a preferably relationship among the properties of the ink (in particular, pigment-based ink) to be used and the fiber material.
On the other hand, the studies by the inventors of the present invention disclosed that as the influence from the fiber itself, there were changes in properties related to the fiber strand diameter. Thus, the second object of the present invention is to provide an ink container in which this properties change is effectively applied.
Being guided by this second object, the present invention provides a preferable ink container, in which a fibrous member constituted of fiber strands with preferable properties in placed across, and in contact with, a filter disposed on the head or container side; more preferably, an ink container, in which a preferable relationship is provided between the diameter of the fiber strands occupying the major portion of the internal volume of the ink container, and the diameter of the fiber strand occupying the ink supply port side (head side), that
Higuma Masahiko
Ikeda Masami
Sugitani Hiroshi
Canon Kabushiki Kaisha
Fitzpatrick ,Cella, Harper & Scinto
Vo Anh T. N.
LandOfFree
Ink container, ink jet head having ink container, ink jet... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Ink container, ink jet head having ink container, ink jet..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Ink container, ink jet head having ink container, ink jet... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2889055