Incremental printing of symbolic information – Ink jet – Fluid or fluid source handling means
Reexamination Certificate
1999-10-22
2002-01-15
Nguyen, Judy (Department: 2861)
Incremental printing of symbolic information
Ink jet
Fluid or fluid source handling means
Reexamination Certificate
active
06338552
ABSTRACT:
FIELD OF THE INVENTION AND RELATED ART
The present invention relates to an ink refilling unit used to refill ink into an ink container which stores the ink to be delivered to a recording head, an ink refilling method, and an ink jet apparatus comprising a refillable ink container and an ink refilling unit. In particular, it relates to an ink refilling system capable of effectively and reliably refilling even an ink container which is integrally and removably mountable on a recording head comprising a plurality of ink storing portions.
Recently, in the field of ink jet recording, an ink jet unit in the form of a cartridge, which integrally comprises a recording head and an ink container, has been used from the standpoint of size reduction, maintenance reduction, and the like. This ink jet unit is easily mountable on the scanning carriage of an apparatus, or is easily removable from the carriage. Further, when the ink in the ink container is completely depleted, the ink jet unit can be easily exchanged with a fresh ink jet unit.
On the other hand, there are high demands for colorization of record. As for the structure currently in use for meeting the above colorization demands using an ink jet unit as described above, there are a few structures for recording in color. For example, in one structure, record is made in color by a plurality of color ink jet units parallelly disposed on a carriage in the scanning direction. In another structure, record is made in color by a color ink jet unit and a black ink jet unit, which are also disposed on the carriage. In the case of the latter structure, the color ink jet unit integrally comprises an ink container for yellow ink, an ink container for magenta ink, an ink container for cyan ink, and a corresponding number of recording heads for ejecting these color inks.
However, the above structures had a problem in that a recording head still usable when the ink in an ink jet unit is completely depleted had been discarded. Therefore, in recent years, a few proposals have been made to solve this problem. According to one of these proposals, the recording head and the ink container are rendered separable.
Thus, it has been proposed to refill the ink container of such an ink jet unit with refill ink. More specifically speaking, according to the system of Graphic Utilities Co., Ltd., a metallic hypodermic needle attached to a bellows type ink supply container is inserted into a hole made in an ink depleted ink container, and the ink in the bellows type ink supply container is injected into the ink depleted ink container as pressure is gradually applied by manually collapsing the bellows type ink supply container. There is also a structure in which the bellows type ink supply container is replaced by a syringe, and the ink is pressure fed into the ink depleted ink container in a manner to give an injection.
The ink refilling methods described above has the following problems. First, since they are manual methods, there are many occasions in which excessive pressure is applied by the operator. As excessive pressure is applied, ink delivery speed exceeds the speed at which the delivered ink permeates into the absorbent member in the ink depleted ink container. As a result, ink drips from the needle tip without being injected into the container. Further, since it is impossible to know the exact amount of ink to be refilled, only way to know whether the ink container is completely filled or not is to wait until ink begin to overflow from the hole made in the ink depleted ink container. Secondly, since a needle must be handled to manually inject ink, the operator is sometimes injured. Thirdly, in order to refill ink without spilling it, it is required to maintain a proper amount of pressure, complicating the structure for satisfying such a requirement. Fourthly, since the pressure necessary to refill ink is manually generated, the time which the operator has to spend to refill ink becomes rather long. Fifthly, before the needle is inserted into the ink depleted ink container, the ink supply container of the bellows type or the hypodermic syringe type is rather sensitive to pressure, and therefore, slight impact causes ink to leak from the needle. Sixthly, when discarding an ink refilling kit, it has to be disassembled into individual components, which are separated according to material type, when it is discarded.
It is conceivable that the ink container opening, which is connected to the recording head, be used to refill ink into the removable ink container of the above described ink jet unit. But, as long as the aforementioned bellows type ink refilling kit or the like is used, the problems described in the foregoing remain. In particular, since the container opening, which is to be connected to the recording head, is substantially larger than the diameter of the needle of the ink refilling apparatus, the ink leakage related problem becomes a matter of more serious concern.
Japanese Laid-Open Patent Application No. 1,744/1995 discloses an ink filling apparatus of a different type. This apparatus comprises an ink cartridge (ink container) and a chamber for storing ink, and fills ink with the use of a capillary element. However, in this apparatus, the path through which ink is delivered when printing, and the section in which ink is filled, are different. Therefore, a sponge member and the capillary element must be pressed against each other to reliably fill ink. This creates two regions different in compression ratio, a region closer to the printing head, and a region closer to where ink is filled. When an attempt is made to refill ink into a completely ink depleted ink container of this type, air is taken into the region between these two differently compressed regions. As a result, it sometimes becomes impossible to continuously carry out printing. Further, when the sponge member and the capillary element are pressed against each other before the ink is completely depleted, ink leaks sometimes as the sponge member is squeezed.
Moreover, in the case of the structure disclosed in Japanese Laid-Open Patent Application No. 1,744/1995, the capillary element is rather long, increasing flow resistance. As a result, it takes a substantially longer time to fill. Also, as the ink within the refill ink chamber decreases, the internal pressure of the refill in chamber decreases. Consequently, the chamber reacts to suck in air. But, since there is no place where air can flow in, ink filling is interrupted. These are the additional problems.
Based on the knowledge and observation described above, the inventors of the present invention have already proposed an ink refilling method and an ink refilling apparatus, which do not have the aforementioned weaknesses. This ink refilling method is used in conjunction with an ink container of a specific type. That is, the ink container has an ink absorbent portion adjacent to the ink delivery port to which an ink recording head is connected, and contains a porous member which generates negative pressure within the container, wherein at least a part of the initially filled ink is consumed through the ink absorbent portion adjacent to the joint portion. This ink refilling method is characterized in that it comprises a step in which the ink meniscus at the ink absorbent portion of the ink container is destroyed, and a step in which the refill ink is filled into the ink depleted ink container by the negative pressure generated by the porous member through the ink consumption from the ink container. As for the essential point of the characteristic, the negative pressure generated through the consumption of the ink held by the porous member within the ink container is used to reliably refill the ink container with ink, without overfilling, that is, while preventing the ink from spilling out of the ink container. Preferably, ink should be refilled from the side from which the ink within the ink container is delivered to the recording head. Such an arrangement assures that ink is reliably refilled into the ink container to prevent
Hirosawa Toshiaki
Kawamura Shogo
Morita Osamu
Sato Osamu
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