Incremental printing of symbolic information – Ink jet – Fluid or fluid source handling means
Reexamination Certificate
1997-01-15
2001-09-11
Barlow, John (Department: 2853)
Incremental printing of symbolic information
Ink jet
Fluid or fluid source handling means
Reexamination Certificate
active
06286944
ABSTRACT:
FIELD OF THE INVENTION AND RELATED ART
The present invention relates to an ink container for containing ink to be supplied to an ink jet head, an ink jet unit having the ink container and an ink jet apparatus having the same. It is usable with recording apparatus or communication apparatus such as a copying machine or a facsimile machine, or with a textile printing apparatus for printing image or the like on textile
An ink jet recording apparatus is now widely used as a means for effect recording on a recording material such as paper, textile or the like in a printer, facsimile machine, a copying machine or the like. In an ink jet recording apparatus, ink is ejected from a recording head to a recording material faced thereto. In one example, it is independently installed in a casing as an ink jet recording apparatus, and in another example it is built in, as an integral part, in various electronic machines such as a word processor, a personal computer or the like. As regards the structure of an ink accommodating portion used is such an ink jet recording apparatus, it is required that the amount of the ink corresponding to the amount of the ink ejected for the recording, can be properly supplied and that the ink does not leak through the ejection outlet when the recording operation is not carried out. Usually, the ink accommodating portion is in the form of a cartridge which is exchangeable. In one example, the ink accommodating portion is made integral with an ink jet head. When the situation that the ink in the ink container can not be ejected from the ink jet recording head, is reached, the ink accommodating portion is disposed of with the recording head. However, in the ink accommodating portion, some ink still remains. The quantity of the non-usable remaining ink is; determined by an ink retaining power of sponge (negative pressure generating material) occupying the entirety of the inside space of the ink accommodating portion, with the result that the quantity is relatively large. In addition, the recording head has to be exchanged with the ink accommodating portion before the performance of the recording head itself is still enough for the operation. This results in cost increase and low cost-performance. Under the circumstances, a proposal has been made that the recording head and ink cartridge are detachably mountable to permit exchange of the ink cartridge alone. In this case, it is further required that the mounting and demounting between the recording head and the ink cartridge can be smoothly carried out without ink leakage and that the ink can be assuredly supplied when they are coupled together.
Japanese Laid-Open Patent Application No. 87242/1988 discloses an ink accommodating portion integral with the recording head, in an ink jet unit provided with a plurality of ink ejection outlets and a foamed material in an ink accommodating portion. In such an ink accommodating portion, the ink is contained in a porous material such as polyurethane foamed material, and therefore, negative pressure is produced by the capillary force inherent to the porous material, and the ink is retained there, that is, the ink leakage from the ink absorbing material is prevented.
However, since the porous material occupies substantially the entirety of the ink accommodating portion, and therefore, the quantity of the ink capable of being retained thereby is limited, and in addition, the quantity of the ink non-usable remaining ink in the porous material is relatively large, and therefore, the use efficiency of the ink is low. Since the ink is filled in the porous material, it is difficult to detect the Remaining quantity of the ink. Furthermore, there is an additional problem that it is difficult to maintain a substantially constant negative pressure in the ink container when the ink is being consumed.
Japanese Laid-Open Patent Application No. 522/1990 has proposed a solution to this problem. It discloses an ink jet recording cartridge in which a primary ink containing portion and a secondary ink containing portion and further the ink jet recording head are communicated with porous materials. In such a cartridge, the use efficiency is improved because the porous material is not contained in the main part of the ink containing portion but is provided only in the ink passage. In addition, by the provision of the secondary ink containing portion, the ink leakage from the primary ink containing portion attributable to the air expansion in the primary containing portion as a result of pressure reduction due to the temperature rise, can be suppressed. Therefore, the negative pressure during the recording operation of the recording head can be maintained substantially constant.
However, since the negative pressure producing means is provided in the ink passage, the porous material contains an amplitude of the ink with the result of insufficient negative pressure when the recording operation is not carried out. Then, there is a possibility that the ink leaks through the orifices of the ink jet recording head by small impact. The ink jet recording head has been made integral with the ink containing portion beforehand, and therefore, it is not usable in an exchangeable ink cartridge In which the ink cartridge is detachably mounted to an ink jet recording head.
When an ink jet recording head and an ink cartridge are detachably mountable to constitute an ink jet unit, and they are mounted on a carriage of a recording apparatus as a unit, a problem of ink leakage upon the exchange of the ink cartridge alone, is a problem. The ink leakage is different from an ink cartridge disposed remote from the recording head. More particularly, there is a liability that the inside of the apparatus is contaminated, electric connection between the recording head and the recording apparatus may be deteriorated, that the recording material may be contaminated, or the like.
This problem is significant recently because both of the recording head and the cartridge are carried on a carriage for the purpose of machine downsizing.
When an ink supply tube is used for a recording head for fluid communication between the recording head and the ink cartridge, a large quantity of the ink is to be supplied for the purpose of increasing the recording speed of the ink jet recording apparatus, and therefore, a relatively large diameter ink supply tube is desired. Therefore, when an ink cartridge is exchanged, and the ink supply tube is inserted to be press-contacted to the ink absorbing material, the absorbing material is compressed by a tip end of the ;ink supply tube with the result that the ink retained therein seeps out. Then, the ink may be discharged to the outside of the ink cartridge with the result of contamination of the recording apparatus or the recording material.
As described hereinbefore, the easy mounting or demounting is desired between the ink cartridge and the recording head, and therefore, it has been difficult to obviate these problems.
Additionally, in order to maintain a high ejection performance, the position of the recording head is strictly limited, and therefore, the deviation thereof due to external force or vibration has to he prevented. In this sense, it has been required that the recording head is not pushed by an ink cartridge when the ink cartridge is mounted thereto To achieve this, it is considered that the ink cartridge imparts the load only in a predetermined direction. In such a case, various direction limiting means have to be provided with the result of complicated structure and/or a bulky structure.
SUMMARY OF THE INVENTION
Accordingly, it is a principal object of the present invention to provide an exchangeable ink jet unit with which an ink container can be easily coupled with a recording head.
It is another object of the present invention to provide an ink jet unit in which an ink container applies only a limited load to the recording head when the ink container is coupled with the recording head.
It is a further object of the present invention to provide an ink jet unit with which perfor
Abe Tsutomu
Asai Naohito
Higuma Masahiko
Ikeda Masami
Kashino Toshio
Barlow John
Canon Kabushiki Kaisha
Fitzpatrick ,Cella, Harper & Scinto
Hallacher Craig A.
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