Incremental printing of symbolic information – Ink jet – Fluid or fluid source handling means
Reexamination Certificate
2000-06-22
2002-06-11
Vo, Anh T. N. (Department: 2861)
Incremental printing of symbolic information
Ink jet
Fluid or fluid source handling means
Reexamination Certificate
active
06402308
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a liquid supply system which utilizes a negative pressure to supply a liquid outside, and more concretely a liquid supply system in a liquid-jet recorder which prints or records characters on a recording medium by supplying a liquid to a recording head and a liquid supply vessel to be used in the liquid supply system.
2. Related Background Art
For a liquid supply method which utilizes a negative pressure to supply a liquid outside, for example, in a field of ink-jet recorders, there have conventionally been proposed and adopted ink tanks which apply negative pressures to ink discharge heads and configurations (head cartridges) in which the ink tanks can be integrated with recording heads. The head cartridges can be further classified into a configuration wherein the recording head is always integral with the ink tank (ink container), and another configuration wherein recording means and the ink container are separate from each other, can be separated from the recorder and are integrated for use.
A method which utilizes a capillary force of a porous material is mentioned as an easiest method to produce the negative pressure in such a liquid supply system. An ink tank which is used to carry out this method has a configuration which comprises a porous material such as a sponge accommodated, preferably in a compressed condition, to store ink entirely in the ink tank and an atmosphere communicating port which is capable of introducing air into the ink container for smoothing ink supply during printing.
However, a porous member which is used as an ink holding member poses a problem that the member lowers an ink accommodating efficiency per unit volume. In order to solve this problem, the applicant has proposed in EP0580433 specification an ink tank which has an ink container chamber substantially sealed as a whole except a communicated section from a negative pressure producing member chamber and is used in a condition where the negative pressure producing member chamber is open to atmosphere. Furthermore, the applicant has proposed in EP0581531 specification an invention which makes it possible to exchange the ink container chamber in the ink tank having the above described configuration.
The above described ink tank supplies ink from the ink container chamber into the negative pressure producing member chamber by a vapor-liquid exchange operation whereby the ink container chamber contains gas as the ink is discharged from the ink container chamber, thereby providing a merit that the ink is supplied under a nearly constant negative pressure during the vapor-liquid exchange operation.
On the other hand, the applicant has proposed in EP0738605 specification a liquid container vessel comprising a cabinet which has a substantial form of a prism, and a container which has outside surfaces identical or similar to inside surfaces of the cabinet and is deformable as an internally accommodated liquid is discharged, characterized in that the container is configured so that portions composing angles of the substantial form of the prism are thinner than center areas of the surfaces. This liquid container vessel allows the container to be adequately contracted as the liquid is discharged (a vapor is not exchanged for a liquid in a phenomenon), thereby being capable of supplying the liquid while utilizing a negative pressure. Accordingly, the liquid container vessel is free from a restriction imposed on a location of its installation as compared with a conventional bag like ink container member and can be disposed on a carriage. Furthermore, the invention allows ink to be held directly in the container and is excellent from a viewpoint to enhance an ink accommodating efficiency.
An ink tank of the above described type wherein a negative pressure producing member chamber and an ink container chamber are adjacent to each other causes a vapor-liquid exchange by introducing a gas into the ink container chamber at a stage to supply ink from the ink container chamber which has a predetermined or fixed accommodating space into the negative pressure producing member chamber.
When the ink is supplied from the ink container chamber into the negative pressure producing member chamber, external air is introduced in an amount corresponding to an amount of the supplied ink, whereby the ink and external air exist in the ink container chamber. The external air is swollen due to an environmental change (for example, a temperature difference within a day), whereby the ink may be introduced from the ink container chamber into the negative pressure producing member chamber. For this reason, there have conventionally been reserved in some cases a practically maximum buffer space in the negative pressure producing member taking into consideration a moving amount of the ink at a swollen ratio of the external air together with various environments of use.
Since the conventional vapor-liquid exchange operation allows atmosphere to be introduced by way of the communicated section as the ink is introduced from the ink container chamber into the negative pressure producing member chamber, the conventional vapor-liquid exchange operation is accompanied by a fear that the ink supply may be insufficient for abrupt consumption of the ink in the negative pressure producing member chamber in the case where the ink is to be supplied in a large amount in a short time from the negative pressure producing member chamber to an outside(a discharging head or the like).
SUMMARY OF THE INVENTION
The inventor et al. have already applied an ink supply system of a type which comprises the above described negative pressure producing member chamber and an ink container chamber which is adjacent to the negative pressure producing member chamber and allows the ink container chamber to be exchanged for the negative pressure producing member chamber, wherein the ink supply system is capable of reducing a buffer space in the negative pressure producing member chamber in various environments and supplying ink at a stable negative pressure during use of the ink container chamber while increasing a capacity for swelling of external air introduced by the vapor-liquid exchange, thereby being more excellent in practical utility, and the present invention has been achieved by a more preferable concept of the inventor et al.
In case of the above described exchangeable type ink container chamber, the ink tank which is repeatedly attached and detached is often equipped with a mechanism such as a valve to prevent ink from leaking while the ink tank is detached. In order to open the valve for attaching the ink tank in this case, a coupling section must have a stroke length in contrast to an ink container chamber which is not of the exchangeable type. However, experiments which were carried out by the inventor et al. have clarified a new problem that air bubbles remain and are accumulated in the coupling section dependently on a structure of a coupling section between the ink tank and the negative pressure producing member chamber in such a case where it is necessary to discharge a large amount of ink outside in a short time in particular.
The present invention has been conceived by the inventor et al. to solve the new technical problem described above, and has an object to provide an ink supply system which comprises a negative pressure producing member chamber and an ink container chamber which is adjacent to the negative pressure producing member chamber and the ink container chamber is exchangeable for the negative pressure producing member chamber, wherein the ink supply system is capable of supplying ink more stably as well as an ink tank to be used in the ink supply system.
Another object of the present invention is to apply the above described ink supply system to a liquid supply system having a configuration wherein an ink container chamber is always integrated with a negative pressure producing member chamber, thereby supplying ink more stably even in the liquid s
Hattori Shozo
Kaneda Tomoyuki
Okuhara Hirofumi
Sugama Sadayuki
Yamamoto Hajime
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