Incremental printing of symbolic information – Ink jet – Fluid or fluid source handling means
Reexamination Certificate
2000-04-27
2003-07-29
Vo, Anh T. N. (Department: 2861)
Incremental printing of symbolic information
Ink jet
Fluid or fluid source handling means
Reexamination Certificate
active
06598963
ABSTRACT:
FIELD OF THE INVENTION AND RELATED ART
The present invention relates to a liquid supplying system for supply liquid to outside with a negative pressure, more particularly, a liquid supplying system and a liquid supply container in which a remaining amount of the liquid in a liquid containing portion.
Heretofore, in a field of ink jet recording apparatus, for example, a liquid supply method for supplying the liquid part with negative pressure, is used in an ink container which is integral with a recording head. The head cartridge is classified into a type in which the recording head and the ink container (ink accommodating portion) are normally integral and a type in which the recording means and the ink reservoir portion are separate parts both of which are separable from the recording device, respectively and are integral in use.
One of the easiest ways of supplying the liquid with negative pressure is the use of a capillary force of a porous material. The ink container using the method includes a porous material such as sponge accommodated or preferably compressed and accommodated in the entirety of the ink container, an air vent capable of introducing air into the ink reservoir portion to permit smooth ink supply during printing. However, the use of the porous member as an ink retaining member involves a problem that ink accommodating efficiency per unit volume is low. In order to solve this problem, EP0580433 which has been assigned to assignee of the present application has proposed an ink container comprising a negative pressure producing member accommodating chamber and an ink reservoir chamber which is substantially sealed except for a communicating portion therebetween, and the negative pressure producing member accommodating chamber is open to the ambience or atmosphere. In EP0581531, a proposal has been made in which the ink reservoir chamber is exchangeable. With such a structure, when the container becomes empty, only the ink reservoir chamber is exchanged, so that amount of waste can be reduced, which is advantageous in terms of environmental health.
In this ink container, the ink is supplied from the ink reservoir chamber into the negative pressure producing member accommodating chamber with gas-liquid exchanging operation involving introduction of the gas into the ink reservoir chamber with a discharge of the ink from the ink reservoir chamber, and therefore, the ink can be supplied out with substantially constant negative pressure when the gas-liquid exchanging operation occurs.
EP0738605 which has been assigned to the assignee of the present application has proposed a liquid container including a substantially prism configuration casing, and an accommodating portion deformable with discharge of the liquid accommodated and having an outer surface which is similar or equivalent to the inner surface of the casing, wherein the thickness of the accommodating portion is such that it is thinner at corner portion than at the central region at each side of the substantially prism configuration. The liquid container is able to supply the liquid with a negative pressure by proper contraction of the accommodating portion with discharge of the liquid (without gas-liquid exchange in the phenomenon). Therefore, the limitation to the location of the container is smaller than a conventional bladder type ink reservoir member, and can be disposed on a carriage. Since the ink is directly accommodated in the accommodating portion, the ink accommodating efficiency is improved. As mentioned above, the liquid supplying system including the negative pressure producing member accommodating chamber and the ink reservoir chamber is good in the improvement of the ink accommodating efficiency and the stability of the ink supply property, and particularly the type in which ink reservoir chamber is exchangeable is good in terms of the environmental health.
However, in the conventional gas-liquid exchanging operation, the ink discharge from the ink reservoir chamber into the negative pressure producing member accommodating chamber is interrelated with the introduction of the ambience through the communicating portion, and therefore, when a large amount of the ink is to be discharged in a short time from the negative pressure producing member accommodating chamber to the outside such as liquid ejecting head, for example, there is a liability at the ink supply from the ink reservoir chamber into the negative pressure producing member accommodating chamber involving the gas-liquid exchanging operation is not sufficient relative to the high rate ink consumption from the negative pressure producing member accommodating chamber. Therefore, in order to solve the problem of the insufficient ink supply, the state in the ink reservoir chamber is important.
As for a method for detecting reduction of the ink remaining amount or the ink remaining amount per se, there is a system in which two electrodes are provided in the ink container, and an electric resistance or the conduction state between the electrodes is detected. In another method, the ink container is made of a light-transmissive material, and an optical sensor is disposed adjacent the ink container to detect the amount of the light transmitted through the ink container.
However, in the type using the electrodes in the ink container, when the ink container is exchanged (exchangeable type), the parts concerned with a detecting means such as electrodes or the like provided in the ink container have to be exchanged with the result of increase of the manufacturing cost of the ink container and increase of the running cost. In the method detecting the quantity of light passing through the ink container, the erroneous detection tends to occur for the light ink such as yellow ink.
In order to solve the program, Japanese Laid-open Patent Application No. HEI 10-109430 has proposed that first electrode is provided in the recording head, and a second electrode of non-contact type is disposed adjacent the ink container without contacting to the ink container, in which a pulse voltage is applied to the first electrode, and the voltage produced at the second electrode is detected, on the basis of which the remaining amount of the ink in the ink container is detected. In the detection system, the input signal to the first electrode is transmitted through the ink from the recording head to the ink container, and a detection signal is obtained on the basis of the capacitive coupling between the ink container and the second electrode.
In the above-described without, the electrostatic capacity provided by the capacitive coupling changes in accordance with an area of the second electrode opposed to the ink. Therefore, if the ink remains in the form of film at a position opposed to the electrode in the ink reservoir chamber, the erroneous detection results, that is, the existence of the ink is detected despite the fact that it does not exist.
The electrostatic capacity provided by the capacitive coupling described above generally changes with the opposing area retained second electrode and the ink, the distance between the second electrode and the ink or the like, and therefore, by regulating these factors, the electrostatic capacity is fundamentally stabilized so that time constant of the detection system for the detection of the ink remaining amount. In the case that plurality of ink reservoir chambers as in an ink jet recording apparatus for color recording or the like, the electrostatic capacity changes with the amount of the ink in the adjacent ink reservoir chamber, and therefore, the time constant of the detection system is influenced. The change of the time constant causes change of the gain of detection signal so that detection accuracy of the ink remaining amount is deteriorated.
SUMMARY OF THE INVENTION
Accordingly, it is a principal object of the present invention to provide a liquid supplying system and an ink container usable with the system which is usable with the ink container disclosed in EP0738605 and/or EP0581531, and into which the presence or
Hattori Shozo
Hayashi Hiroki
Kitabatake Kenji
Koshikawa Hiroshi
Shimizu Eiichiro
Canon Kabushiki Kaisha
Fitzpatrick ,Cella, Harper & Scinto
Vo Anh T. N.
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