Incremental printing of symbolic information – Ink jet – Fluid or fluid source handling means
Reexamination Certificate
1999-06-17
2001-06-26
Le, N. (Department: 2861)
Incremental printing of symbolic information
Ink jet
Fluid or fluid source handling means
Reexamination Certificate
active
06250748
ABSTRACT:
FIELD OF THE INVENTION AND RELATED ART
The present invention relates to a liquid accommodating container for supplying liquid out with a negative pressure to a recording station such as a pen, ink ejection portion or the like, a manufacturing method for the container, an ink jet cartridge containing the container portion and an ink jet recording head portion, and an ink jet recording apparatus, and more particularly, to use of blow molding for formation of the ink container per se in the field of ink jet recording.
A container for accommodating liquid is known wherein the liquid is supplied out of the container while maintaining a negative pressure within the container. Such a container performs appropriate liquid supply for the liquid using portion such as a nib or tip of a pen or recording head connected to the container, by the negative pressure produced by the container per se.
Various liquid accommodating containers of this type are used, but the usable ranges thereof are rather limited. One of the reasons for this is that there has not been an one easy to manufacture and having a simple structure.
For example, in the field of the ink jet recording requiring a proper negative pressure property, a container having a sponge therein as a generation source for the negative pressure or a bladder-like container having a spring providing force against an inward deformation due to the consumption of the ink, as disclosed in Japanese Laid Open Patent Application No. SHO-56-67269, Japanese Laid Open Patent Application No. HEI-6-226993, for example. U.S. Pat. No. 4,509,062 discloses an ink accommodation portion of rubber having a conical configuration with a rounded top having a smaller thickness than the other portion. The round thinner portion of the circular cone portion provides a portion which displaces and deforms earlier than the other portion. These examples have been put into practice, and are satisfactory at present.
However, the negative pressure generating mechanisms described above is relatively expensive, and therefore, does not suit for the writing devices such as markers, plotters having writing tips. The use of the complicated negative pressure generating mechanism is not desirable since it result in bulkiness of the writing device.
In writing devices, the use is made with a felt capable of generating a negative pressure and of introducing the air from the tip to permit supply of the ink thereto. The main problem of this type of the gas-liquid exchange structure for the ink supply is the ink leakage at the tip. In order to solve this problem, an ink retaining mechanism has been proposed wherein a great number of fins are formed at predetermined intervals between the tip and the liquid accommodating container extending in a direction perpendicular to the ink supply direction, for the purpose of preventing the ink leakage by retaining the ink which is going to leak upon the ambient condition change or the like. However, such a mechanism results in a relatively large amount of non-usable ink remaining in the container.
The ink supplying system of such writing devices, generally uses an open type, which leads to evaporation of the ink, with the result of reduction of the usable amount of the ink. Therefore, ink evaporation suppression by using substantial sealed type is desirable.
The description will be made briefly about the substantially sealed type in the ink jet recording. When a negative pressure generation source is not used in an ink supplying system, the ink is supplied using the level difference relative to the ink using portion(ink ejection head), that is, the static head difference. This does not require any special condition in the ink accommodation portion, and therefore, a simple ink accommodation bladder is used in many cases.
However, in order to use a closed system, the ink supply path has to extend between the ink accommodation bladder to the ink using portion(ink ejection head) thereabove with the result that a long ink supply tube is required, so that the system is bulky. In order to reduce or eliminate the static head difference of the ink supply path, an ink container capable of providing the ink ejection head with a negative pressure, has been proposed and put into practice. Here, a term “head cartridge” is used to cover an unified head and ink container.
The head cartridge is further classified into a type wherein the recording head and the ink accommodating portion are always unified, and a type wherein the recording means and the ink accommodating portion are separable, and are separately mountable to the recording device, but are unified in use.
In either structure, the connecting portion of the ink accommodating portion relative to the recording means is provided at a position lower than the center of the ink accommodating portion in order to increase the usage efficiency of ink accommodated in the ink accommodating portion. In order to stably maintain the ink and to prevent the ink leakage from the ejection portion such as a nozzle in the recording means, the ink accommodating portion in the head cartridge is given a function of generating a back pressure against the ink flow to the recording means. The back pressure is called “negative pressure”, since it provides negative pressure relative to the ambient pressure at the ejection outlet portion.
In order to produce the negative pressure, the use may be made with capillary force of a porous material or member. The ink container using the method, comprises a porous material such as a sponge contained and preferably compressed in the entirety of the ink container, and an air vent for introducing air thereinto to facilitate the ink supply during the printing.
However, when the porous material is used as an ink retaining member, the ink accommodation efficiency per unit volume is low. In order to provide a solution to this problem, the porous material is contained in only a part of the ink container rather than in the entirety of the ink container in a proposal. With such a structure, the ink accommodation efficiency and ink retaining performance per unit volume is larger than the structure having the porous material in the entirety of the ink container.
From the standpoint of improving the ink accommodation efficiency, the bladder-like container using or not using the spring, or the ink accommodating container of rubber is usable.
Such an ink container is widely used now.
However, further improvement is desired.
For example, further increase of the ink accommodation efficiency is desirable. More particularly, a larger amount of the ink is desired to be contained in the same volume of the container.
The smaller number of parts constituting the ink container and simpler container are desirable. An increase of the yield and reduction of the quality control items are desired.
SUMMARY OF THE INVENTION
Accordingly, it is a principal object of the present invention to provide a liquid accommodating container wherein the liquid can be supplied out with a stabilized negative pressure.
It is another object of the present invention to provide a negative pressure using type liquid accommodating container, a manufacturing method therefor, and a manufacturing apparatus, wherein the inside space of a container can be used to the maximum to accommodate the ink, and the variation of the quality is low.
It is a further object of the present invention to provide a negative pressure using type liquid accommodating container, manufacturing method therefor, and liquid supply method, wherein the liquid supply performance is high with a simple structure.
It is a further object of the present invention to provide a liquid supply system and a liquid accommodating container usable therewith, wherein a static head difference is used, and size is small.
It is a further object of the present invention to provide a liquid accommodating container which is particularly suitable to an ink jet head.
It is a further object of the present invention to provide a novel ink supply system.
According to an aspect of the present inven
Okada Hideo
Sasaki Toshiaki
Sugama Sadayuki
Canon Kabushiki Kaisha
Fitzpatrick ,Cella, Harper & Scinto
Le N.
Nghiem Michael
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