Incremental printing of symbolic information – Ink jet – Fluid or fluid source handling means
Reexamination Certificate
1998-05-26
2001-07-10
Le, N. (Department: 2861)
Incremental printing of symbolic information
Ink jet
Fluid or fluid source handling means
Reexamination Certificate
active
06257711
ABSTRACT:
FIELD OF THE INVENTION AND RELATED ART
The present invention relates to an ink filling method and apparatus for an ink cartridge usable with an ink jet apparatus.
A recording apparatus such as a printer, copying machine, facsimile machine or the like and a recording apparatus used as an output apparatus of a combined electronic apparatuses or work station including computer, word processor or the like, is constituted such that image is recorded on a recording material such as a sheet of paper or plastic material in accordance with image information. The recording apparatuses can be classified into an ink jet type, a wire dot type, a thermal type, a laser beam type and so on on the basis of recording system.
In an ink jet type recording apparatus, ink is ejected onto a recording material through recording means (recording head). It comprises the following advantages. The recording means can be significantly downsized, and fine images can be recorded at a high speed. The recording is possible without particular treatment on plain paper. The running cost is low, and the noise is low because it is a non-impact type apparatus. In addition, it is easy to effect color image recording use different color inks.
Among ink jet recording means, an ink jet recording means (recording head) using thermal energy to eject the ink is advantageous in that high density liquid paths (ejection outlets) can be easily provided by the use of electrothermal transducers, electrodes, liquid passage walls and top plate produced through semiconductor manufacturing process including etching, evaporation, sputtering and so on. Therefore, further downsizing is possible.
An ink container used with the ink jet recording apparatus is required to supply in good order an amount of the ink corresponding to the ejections of the ink through the recording head by the recording operation and is required not to leak the ink through the ejection outlets when the recording operation is not carried out.
Additionally, in the case that the ink container is a replaceable or exchangeable type, it is also required that the mounting and demounting of the ink container is smooth without ink leakage, thus assuring the ink supply to the recording head.
As an example of an ink container usable with an ink jet recording apparatus, Japanese Laid-Open Patent Application No. 87242/1988 (first prior art) discloses an ink jet recording cartridge comprising an ink container, a foamed material therein and a plurality of ink ejection orifices.
With such a container, a negative pressure production and ink retention by the capillary force of the foamed porous material such as polyurethane foamed material in which ink is contained, are possible, so that the ink leakage from the container can be prevented.
However, in the first prior art, the foamed material is required to occupy substantially the entirety of an ink containing portion, so that the amount of the ink contained therein is limited, and the amount of the ink remaining in the foamed material as non-usable ink is relatively large, and therefore, the ink utilization factor is not high. Additionally, detection of the amount of the remaining ink is difficult, and the maintenance of constant negative pressure is difficult during the consumption of the ink.
In the case of the ink cartridge having an ink containing portion into which the foamed material is inserted, a corner or corners may be twisted upon the insertion thereof, as the case may be. If this occurs, the compression distribution of the foamed material is not uniform with the possible result of non-uniform distribution in the ink in the ink containing portion.
In this case, even if a sufficient amount of the ink is still contained, the ink path may be blocked due to the non-uniformity of the negative pressure producing performance. If this occurs, the ink may be ejected improperly and/or, the ink can be easily leaked out upon impact thereto, due to the concentration of the ink adjacent the air vent. Accordingly, high accuracy is required upon the insertion of the foamed material into the ink cartridge, thus imposing difficulty on the manufacturing.
Recently, for the purpose of reducing the running cost, a used-up ink cartridge is refilled with the ink. As for the method of refilling the ink, U.S. Pat. Nos. 4,967,207 and 4,968,998 propose that the pressure in the container is reduced through the air vent, and then the ink is injected using a special ink refilling tube.
However, when the ink is injected in this manner, the ink refilling port is disposed away from the recording head, and the pressure reduction tends to be insufficient when the pump in the apparatus is used to reduce the pressure, and therefore, the ink is not uniformly distributed in the porous foamed material with the result of difficulty in formation of the ink path communicating with the recording head, after the refilling. Additionally, when the ink is refilled to the limit of the containing capacity, the ink may be leaked through the air vent.
Even if an attempt is made to inject the ink through the air vent, the ink flow upon the injection can not be controlled with the result that the pressure of the foamed material reaches to the normal operational state before the completion of the ink injection. When the ink continues to be injected to the limit of the capacity, the ink injection through the air vent becomes not possible because of the balance of the internal pressure of the ink container, or the ink may be discharged with the air through the air vent.
Therefore, the refillable amount of the ink is smaller than the initial ink capacity. Because the ink is not uniformly distributed in the foamed material, there is a possibility that the ink path to the ejection outlets is not easily formed upon the start of the recording operation immediately after the refilling, with the result of longer time required for the initial operations.
If an attempt is made to increase the internal capacity of the ink with the injection variation permitted for the purpose of preventing the above-described ink leakage, results in bulky container, and therefore, the bulky apparatus, against the user's needs. Additionally, the necessity for the sucking device for reducing the pressure in the ink cartridge leads to the large size of the recording apparatus and the refilling apparatus.
Accordingly, with the structure in which the porous material occupies the entirety of the inside of the ink containing portion of an ink cartridge, the ink containing efficiency, that is, the amount of the contained ink per unit volume, is low.
As an ink cartridge having a high ink containing efficiency, Japanese Laid-Open Patent Application No. 522/1990 (second prior art) discloses an ink jet recording cartridge in which the porous materials are disposed between a first ink container and a second ink container, and between a second ink container and an ink jet recording head.
This ink jet recording cartridge, the porous material is not contained in the ink containing portion, but it is disposed only in the ink passage, by which the ink capacity is larger than that of the first prior art. Additionally, by the provision of the second ink container, the ink distribution and the air flow are adjusted during the recording operation or upon temperature rise, thus stabilizing the vacuum in the recording head.
However, in the second prior art, the porous material contains a large amount of the ink since it is disposed in the ink passage, and therefore, the negative pressure or vacuum by the capillary force of the porous material is not sufficient, when the recording operation is not carried out, with the result that the ink tends to leak through the ejection outlets of the ink jet recording head upon significant impact.
When the ink is refilled in such an ink cartridge as not provided with an air vent, the pressure of the ink cartridge is reduced, and the ink is injected through a port other than the air vent.
In this case, the ink container is required to be hermetically closed to maintain the negative
Abe Tsutomu
Higuma Masahiko
Ikeda Masami
Ishinaga Hiroyuki
Kashino Toshio
Canon Kabushiki Kaisha
Fitzpatrick ,Cella, Harper & Scinto
Le N.
Nghiem Michael
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