Ink refilling method and apparatus, ink container refilled therewith and ink jet apparatus comprising ink refilling apparatus

Abstract: An ink refilling apparatus (500,1500) includes an ink absorbing member (6,26y,26m,26c,1006) at a connecting portion relative to an ink recording head; an ink container (1,21) holding portion to which an ink container for the ink recording head provided with a porous ink retaining member capable of producing a negative pressure therein, is mountable; an ink discharging means for accommodating the ink to be refilled into the ink container (1,21) and supplying the ink to the ink absorbing member (6,26y,26m,26c,1006) of the ink container; wherein after the ink of the ink absorbing member member (6,26y,26m,26c,1006) and the ink retained by the ink discharging means are contacted to each other, the ink is refilled using a negative pressure produced by consumption of the ink from the ink container; the improvement residing in that ink absorbing member (6,26y,26m,26c,1006) having substantially the same property as the ink absorbing member of the ink container is provided at an ink container connection side of the ink discharging means, the ink absorbing members are contacted to each other upon mounting of the ink container, by which a meniscus formed at a contact surface of the ink absorbing member, is broken.

Description: The present invention relates to an ink refilling system used to refill ink into an ink container which stores the ink to be delivered to a recording head. 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. Document EP-A-0 605 183 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 inserted into an ink delivery port of the ink container such that the capillary element is pressed against a sponge member in the ink container. This creates a compressed region which, after the refilling, expands such that air is taken into the region of the sponge member next to the ink delivery port. 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 document EP-A-0 605 183, 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 ink 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 system and method, 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 member 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 member. This ink refilling method is characterized in that it comprises a step in which the ink meniscus at the ink absorbent member 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 the interruption of the ink delivery to the recording head. Compared to the conventional method, the ink refilling method described in the foregoing can further improve on operational efficiency. More specifically, since the conventional ink refilling method employs only an unsophisticated filling device, the user has to hold both the ink container and the filling device at the same time, and therefore, it is low in operational efficiency. Such inefficiency can be eliminated with the use of the ink refilling apparatus and the ink refilling method, which were described in the foregoing paragraph, so that ink is prevented from overflowing, and above all, ink can be refilled into the ink container in a manner to render the condition of the refilled container substantially the same as that of a freshly opened ink container. More specifically, the above ink refilling system which is used in conjunction with an ink container for an ink recording head, in which an ink absorbent member is disposed in the ink delivery port connectible to an ink recording head, and in which an ink retaining member formed of porous material capable of generating internal negative pressure is disposed, comprises: a section for holding the ink recording head; a means for holding the refill ink for the ink container as well as delivering the refill ink to the ink absorbent member of the ink container; and a means disposed on the ink delivering means to destroy the meniscus of the ink absorbent member, wherein after the ink within the ink absorbent member is united with the ink retained in the ink delivering means, by the meniscus destroying means, the ink container is filled with the refill ink by the negative pressure induced through the ink consumption from the ink container. The above described process (or means) for destroying the ink meniscus means any process (or means) capable of uniting the remaining ink in the ink container with the refill ink by destroying at least a part of the meniscus formed by the internal negative pressure of the ink container; for example, positive pressurization of the refill ink, or negative pressurization of the internal space of the ink container. A preferable means is the following one: the meniscus is destroyed by inserting a rod-like member, having a very small sectional area and being constituted of strands of fiber arranged to provide microscopic gaps, into the ink absorbent member, along with the refill ink which permeates the rod-like member due to capillarity. Regarding the ink refilling system described above, the ink absorbent member of the ink container is positioned at a lower level in terms of the gravitational direction than the porous member of the ink container so that the refill ink is delivered upward from below. With this arrangement, the refill ink can be reliably filled into the ink container through the ink delivery port of the ink container. Further, according to the above described system, the ink absorbent member composed of strands of fiber unidirectionally bundled to improve ink delivery efficiency with which ink is delivered from the ink container to the recording head is also used on the refill mechanism side; therefore, the refill ink is more uniformly filled into the ink container. In particular, in the case of an ink container from which ink is delivered downward (preferably, straight downward) to the ink recording head when recording, the ink remaining in the ink container uniformly settles on the ink delivery port side; therefore, such an ink container can function more efficiently. The ink refilling system described above is also applicable to an ink container comprising a plurality of sub-containers for holding different inks. In the case of such an application, all the sub-containers are filled with the aforementioned porous material, and their ink delivery ports provided with their own ink absorbent delivery members are disposed on the same side of the ink container. Further, each sub-container is filled with refill ink by its own refill ink delivering means through the aforementioned ink absorbent delivery member. With this provision, each sub-container can be simply and reliably filled with the refill ink, to a predetermined ink level of its own, without color mix-up and without being overfilled. An ink refilling system comprising the features of the precharacterizing clause of claim 1 and an ink jet recording apparatus are known from document EP-A-0 536 980. The known ink refilling system is incorporated into the known ink jet recording apparatus. The ink container of the known system and ink jet recording apparatus is provided with a hole in a side wall of a housing of the ink container. For refilling ink, the ink discharge member is inserted into the hole and press-contacted either directly with the porous member or with an ink reception member formed by a thin layer of a rigid porous material, for example porous ceramic. After the ink discharge member and the ink reception member have been press-contacted to each other, the refill ink is sucked into the ink container as a result of capillarity. If, after consumption of most of the ink contained in the ink container, the ink discharge member is directly contacted with the porous member for refilling the ink container, the remaining ink in the ink container and the refill ink are not reliably united. If the ink discharge member is press-contacted with the ink reception member formed by a thin layer of a rigid porous ceramic material, the flow resistance in the path through which the refill ink is filled to the ink container is high and the refilling time is increased. SUMMARY OF THE INVENTION The primary object of the present invention is to reliably unite the remaining ink in the ink container used with the ink recording head, with the refill ink for the ink container. The second object is to quickly fill up the ink container by minimizing the flow resistance in the path through which the refill ink is filled into the ink container. The primary object and the second object are achieved by the ink refilling system according to claim 1. The inventors of the present invention reconfirmed based on the above observation that the conventional ink refilling process for an ink jet recording apparatus was controlled by external factors such as the capacity of the ink delivery mechanism of the ink refilling apparatus, and therefore, the process was liable to be hindered by excessive or insufficient external force, and that currently, when an ink container which contained the ink retaining porous member (being at least partially compressed, or entirely compressed to half or quarter the precompression size) was filled with ink for the first time, ink was forcefully filled into the porous member by reducing the internal pressure of the ink container. Also during the above observation, they discovered a phenomenon that as ink was consumed from the ink retaining porous member filled with ink, the porous member developed a substantial amount of negative static pressure, that is, the sum of minute negative static pressure induced in each microscopic pores of the porous member. Thus, they realized that using this phenomenon for refilling the ink container is the most rational way to refill the ink container, and made the present invention which made it possible to reliably refill the ink container regardless of the amount of the ink remaining in the ink container, without causing an ink overflow. In the system according to the invention, the porous member disposed in the ink container is capable of generating negative pressure within the ink container after at least a portion of the initially filled ink is consumed. The ink meniscus formed in the ink delivery member of the ink container is destroyed by contacting the ink delivery member and the ink discharge member, and the refill ink is filled into the ink container due to the negative pressure which the porous member develops as the ink is consumed therefrom. The gist of the present invention is to use the negative pressure generated as the ink retained in the porous member of the ink container is consumed, to reliably refill the ink container, without overfilling or causing an ink overflow. Further, it is most desirable that the refill ink is filled into the ink container through the side through which ink is delivered to the recording head portion. This is because such an arrangement can prevents interruption of ink flow, and therefore, can most reliably refill the ink container. Further, according to the present invention, the ink delivery member is composed of strands of fiber unidirectionally bundled to improve ink delivery efficiency with which ink is delivered from the ink container to the recording head, and also the discharge member comprises a bundle of unidirectional fibers. Advantageous developments of the refilling system according to the invention are defined in the dependent claims. These and other objects, features and advantages of the present invention will become more apparent upon a consideration of the following description of the preferred embodiments of the present invention taken in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a schematic side view of a partially cutaway ink container which stores black ink. Figure 2(a) is a schematic side view of a partially cutaway ink container which stores color inks (yellow, cyan, and magenta ink), and Figure 2(b) is a bottom view thereof. Figure 3 is a schematic sectional drawing depicting an example of an ink filling system in accordance with the present invention. In the drawing, an ink container is connected to an ink refilling apparatus. Figure 4 is a sectional drawing, illustrating the ink delivery member 27Y of the ink container, and the ink discharge member 517Y of the ink refilling apparatus, immediately before they are connected. Figure 5 is a graph showing the relationship between the amount of ink consumption and negative static pressure. Figure 6 is a schematic sectional drawing depicting an ink refilling system comprising a chicken feeder type ink refilling apparatus in another embodiment of the present invention. Figure 7 shows mounting of ink container to an ink refilling apparatus. Figure 8 shows a relationship between positions P5 of the ink container and resistance against insertion thereof during the mounting thereof, wherein (a) shows positions P5 in stages I - VII, and (b) is a graph showing the relationship. DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described with reference to the drawings. First, the general feature of an ink container will be described. Figure 1 is a partially cutaway side view of an ink container 1 storing black ink, and depicts the general structure thereof. An ink container 1 comprises an ink holding shell 2, a lid 3, and a top member 4. The lid 3 is provided with an air ventilation opening (unillustrated), and covers the opening of the shell 2. The top member 4 is provided with a space which plays a role of a buffer chamber for preventing ink from leaking out through the air ventilation opening of the lid 3, an air ventilation opening of its own, and a knob 4a, and is fixed to the top surface of the lid 3. The air ventilation opening of the top member is disposed away from the air ventilation opening of the lid 3. The knob 4a is used to mount the ink container 1 on an ink jet unit or to remove it. The bottom wall of the ink container is provided with an ink delivery port 8, a rib 15, and slanted portions 14a and 14b. The rib 15 surrounds the ink delivery port 8, and they are connected by the slanted portions 14a and 14b. The ink reception tube of the ink jet unit 101 on which the ink container is mounted is inserted into the ink delivery port 8. The ink delivery portion of the ink container filled with an porous member 6 is provided with an ink delivery member 7 formed of a bundle of fiber strands (hereinafter, ink delivery member). The provision of a bundle of fiber strands in the ink delivery member 7 is highly effective to stabilize the pressure which is desirable to be present after the ink reception tube of the recording head, which is equipped with a filter, is pressed onto the ink delivery member 7. The configuration of the ink delivery member 7 is as shown in Figure 1, for example. That is, the ink delivery member 7 is disposed between the porous member 6 and the ink delivery port 8. It is desirable that the ink delivery member 7 is composed of ink absorbent material, and has a bundle of fiber strands at least on the side which faces the ink container. In order to support the ink delivery member 7 in the ink container, a support member 9 is inwardly erected from the peripheral edge of the ink delivery port 8. A part of the internal surface of the support member 9 is provided with a slit for connecting the internal space of the ink container to the outside. An ink delivery member is such a member that guides ink only in one direction. In this embodiment, it guides ink from the porous member toward the ink delivery port 8. In this embodiment, the porous member disposed in the ink storing portion of the ink container is a piece of ink absorbent material. It is compressed into the ink container. As for the ink absorbent material permeable by ink, sponge or the like can be listed, for example. The ink delivery member 7 is fixed in its holder portion in the ink container, and is in contact with the porous member 6 compressively disposed in the ink container, maintaining a predetermined contact pressure and thereby, keeping the contact portion of the porous member deformed. This deformation of the porous member increases capillary force, and therefore, ink is concentrated to the adjacencies of the ink delivery member 7. Therefore, even after the recording head and the ink container is separated, ink always collects in the ink delivery member 7, and forms meniscus on the surface of the ink delivery member 7, on the side facing the ink delivery port 8. As a result, air is not sucked into the ink container. Also, after the recording head and the ink container is connected, and an ink path is established, the continuous presence of ink in the adjacencies of the ink delivery member 7 helps ink to flow into the ink delivery member 7, and prevents the ink flow from being interrupted. As a result, the amount of the ink which otherwise will be left unused in the ink container is reduced, improving thereby ink usage efficiency. The ink delivery member 7 is composed of strands of fiber. Proper material for the ink delivery member 7, which is desired to be chemically stable, and also to be good in wettability, is polyester, nylon, polypropylene, polyethylene, cellulose, polyurethane, and the like. As for the criteria for good wettability, generally, having a small contact angle relative to ink may be listed. Even material such as Teflon having a large contact angle can be used as long as it is processed to give it hydrophilic properties. However, in consideration of the fact that the process to give hydrophilic properties increases the number of manufacturing steps, and also product cost, material with a smaller contact angle relative to ink is preferable. In addition to the materials listed above, metallic fiber, glass fiber, carbon fiber, or the like, may be employed. Also, the listed materials may be employed in combination. Since the ink delivery member constitutes a part of the ink flow path, it must be given unidirectionality in ink delivery. Further, since it is pressed against the ink reception portion of the recording head, it must have physical strength to retain its original configuration. In order to satisfy the above requirements, fiber strands are desired to be bundled. The condition which determines the upper limit for the thickness of the fiber of the ink delivery member is the desired state of contact between the aforementioned filter disposed in the ink reception area, and the ink delivery member. In view of this condition, the thickness of the fiber is desired to be no more than 0.05 mm. Further, the bottom limit for the fiber thickness is desired to be no less than 0.01 mm, in view of the fact that a number of fiber strands are to be bundled to form an ink delivery member, and in order to reduce cost and also to simplify the process for bundling the fiber strands. As to means for keeping a number of fiber strands bundled together, there is a method, among others, in which the peripheral portion of a rod-like member (ink delivery member 7) constituted of a temporarily bundled fiber strands, is hardened with resin binder, that is, the peripheral portion of the ink delivery member is rendered hard. Referring to Figures 2(a) and 2(b), the color ink container 21 containing color inks (in this embodiment, yellow (Y), cyan (C), and'magenta (M) inks) is formed as a single piece ink container integrally comprising sub-containers for these color inks. Referring to Figure 2(b), the space within the ink storage shell 22 of the color ink container 21 is partitioned with partition members 36 and 37 which form substantially a letter T. The amount of the color ink stored in each sub-space created by the partition members 36 and 37 is the same as those in the other sub-spaces. Dividing the ink container space in this manner makes it possible to dispose the ink delivery port of each sub-container adjacent to the point where three sub-container meet. Partitioning the ink container space in the manner described above, and disposing the ink delivery ports of the sub-containers adjacent to the point where the sub-containers created by the partition members forming substantially the letter T meet, make it possible to extremely reduce the space necessary to join the ink container with the recording head, and also to reduce the projection area of the ink container. In addition, the amount of the ink storable in the ink container can be rendered rather large for the smallness of the projection area of the ink container, and the smallness of the joining space. The interior of the ink container 21 is structured in the same manner as the ink container 1 illustrated in Figure 1. That is, ink absorbent porous members 26Y, 26M and 26C are disposed in the corresponding sub-containers, and ink delivery members 27Y, 27M and 27C are disposed between the porous members 26Y, 26M and 26C and the corresponding ink delivery ports 28Y, 28M and 28C. A part of the internal surface of each of support member 29Y, 29M and 29C which support the corresponding ink delivery members 27Y, 27M and 27C within the corresponding sub-ink containers, is provided with a slit which connects the internal space of the sub-ink container to the outside. A lid 23 is provided with a rib 33 which creates a predetermined amount of space between the porous members 26Y, 26M and 26C and the lid 23. The external surface of the lid 23 is provided with a ridge 23a, which is engaged with the overhang portion of the ink jet unit to apply, from above, downward pressure to the ink container 21. This downward pressure keeps the mounted ink container 21 stable. Figure 3 shows an example of the ink refilling system in accordance with the present invention, the system comprising a refilling apparatus 500 and the ink container 21 connected therewith. An ink container holding portion (hereinafter, holder) 501 comprises a shell 503, an overhang portion 505, a front plate 513, an ink discharge member 517 (517Y in this drawing), an ink discharge port 507 (507Y in this drawing), and an elastic member 508. The ink discharge member 517Y is substantially the same in length as the ink delivery member 27Y of the ink container 21, and is pressed in the ink discharge port 507Y, with its contact tip sticking out of the ink discharge port 507Y. The holder also comprises a number of positioning members and the like which allow the ink container 21 to be removably mounted in the holder. The bottom portion of the main structure of the ink container refilling apparatus 500 comprises an ink chamber 504, an ink discharge tube 506, and an air entrance 502. The ink chamber 504 is to contain ink 510. In this embodiment, ink is described as yellow ink, and the description given below is also true with cyan (C) ink and magenta (M) ink. First, filling of ink into the ink refilling apparatus 500 will be described. First, ink is filled into the ink chamber 504 before the ink discharge member 517Y is pressed into the ink discharge port 507Y. Therefore, ink can be easily filled through the ink discharge port 507Y. After the ink chamber 504 is filled with ink, the ink discharge member 517 is pressed in. Since pressing alone is liable to allow the ink discharge member 517Y to come off during transportation, it is desirable that the ink discharge, member 517 be glued. Simply pressing the ink discharge member 517Y into the ink discharge port 507 does not cause the ink to reach the ink discharge member 517Y; in other words, it does not cause the refilling apparatus to function. Therefore, ink is caused to come in contact with the ink discharge member 517Y by, for example, lifting the right-hand side (air entrance 502 side) of the refilling apparatus, in Figure 3. The ink discharge member 517Y is constituted of bundled strands of fiber as those of the ink delivery member 27Y, so that ink is sucked upward into the ink discharge member 517Y, and retained there, by capillary force. Therefore, even after the tilted refilling apparatus is leveled again as it was, ink remains in the ink discharge member 517Y as well as the path thereto from the ink chamber 504. Then, the air entrance 502 is covered with a rubber cap (unillustrated) to prevent ink from leaking. As a used ink container 21 is mounted after removing the aforementioned cap, the used ink container 21 tries to suck up the ink 510 due to the presence of static negative pressure in the porous member 26 of the ink container 21, but if air remains between the ink meniscus (unillustrated) on the side of the ink discharge member 517Y of the refilling apparatus 500, and the ink meniscus (unillustrated) on the side of the ink delivery member 27Y of the ink container 21, refilling of the used ink container 21 does not occur; therefore, the user has be very sure that these members are directly in contact with each other. Referring to Figure 4, before two ink delivery member 27Y and the ink discharge member 517Y are placed in contact with each other, ink meniscuses 602 and 603 are present on the surfaces (exposed surfaces) of the members. Figure 7 illustrate a typical ink container installation sequence, in particular, for the color ink container 21. First, referring to Figure 7, the ink container 21 is picked up by the tab portion, and is inserted into the ink container accommodating portion, as illustrated by a state I. At this time, the top portion 514 of the front plate 513 is placed in contact with a point (P1) of a lateral wall of the ink container, being used as the guide, and one (P2) of the bottom corners of the ink container is placed in contact with a lateral wall of the casing 503. Then, the bottom corner P2 is gradually slid downward, whereby the ink container is rotated about P1, settling in a state illustrated in Figure 7. As the bottom corner P2 is further slid downward, a state III is realized. It is extremely important, at this time, that the user can feel with his hand that the ink container is smoothly sliding. In this embodiment, this is accomplished by giving an R-shape (approximately R3) to the ink container corner (P2) that is abutted on the lateral wall surface (rear side) of the casing 503. This provision of the R-shaped corner allows the ink container to slide smoothly, being virtually rotated about the contact point P1 established between the ink container and the top portion 514 of the front plate 513; therefore, the ink container is smoothly slid downward as the contact points P1 and P2 are allowed to shift smoothly in coordination, giving the user a preferable feel of contact. When the ink container is in the state III, the other bottom corner portion P3 of the ink container, which has reached the internal bottom portion of the casing 503, is in contact with the casing 503, and as the ink container is further inserted, the slanted portion, which is formed so as to continue from the R-shaped portion given to the other bottom corner P3, comes in contact with the internal wall of the casing 503. In the Figure 7 that illustrates the stage III, the ink discharge port 507Y is ready to enter the ink delivery port 28Y of the ink container (it should be noted that the ink discharge port 507M is also ready to enter the ink delivery port of the magenta ink container disposed next to the yellow ink container). However, the ink discharge port 507Y comprises therein the aforementioned ink discharge member 517Y constituted of the fiber bundle, the fiber bundle is sometimes damaged through the friction between the fiber bundle and ink delivery port; therefore, it is preferable that the dimensions of the casing and ink container are adjusted so that the ink discharge port does not come in contact with the ink delivery port of the ink container, in the state III, and a state IV, which will be described. At this time, the tip of the ink discharge member 517Y of the ink discharge port 507 contacts the ink delivery port, but, since the port is given the slanted surface as illustrated in Figure 2(b), the insertion continues without a hitch. Further, since the ink container goes through the rotational movement during its installation, each ink discharge port comes in contact with the corresponding ink delivery port at a different time, depending on where each ink delivery port is located; therefore, the inclination of its slanted surface is rendered gentler in the order of its contact with the corresponding ink discharge port. In other words, the yellow and magenta ink containers are provided with a slanted surface having substantially the same inclination, and the slanted surface of the ink delivery port of the cyan ink container is the most inclined. Since the ink delivery port portion is provided with the slanted surface, and its inclination is rendered gentler on the upstream side relative to the direction in which the ink container is inserted into the casing, and is rendered steeper on the opposite side, the ink container can be rotated for the installation, being disposed right next to the port portion, and yet, without causing the ink discharge member 517, which is to be connected to the ink container while the ink container is rotatively inserted in the casing, to interfere with the port portion, and also, the ink delivery port portion can be designed without being expanded more than an ordinary one. Now then, as the insertion is continued, the bottom portion P3 of the ink container, at which the ink container also comes in contact with the casing, slides and shifts toward the font side, causing the ink container to be inclined against the slanted portion of a rib 515, which is provided on the casing 503, on the internal surface of the top portion 514. At this time, the top corner P5 of the ink container, that is, the corner on the downstream side relative to the vertical direction in which the ink container is inserted, comes in contact with the top end of the slanted portion provided on the shoe portion 505, and begins to generate the insertion resistive feel (state IV illustrated in Figure 7). Referring to Figure 8, it shows the relation displayed between the location of P5 and the insertion resistive force during the ink container inserting operation. In the states I - III, there is no insertion resistive force since there is no contact between P5 and the casing, as shown in the drawing, and then, in the state IV and thereafter, the resistance gradually increases. Figure 7 illustrates a state V in which the insertion has gone further, and in this state, the corner P5 is at a location where the insertion resisting force is much larger than in the state IV, as Figure 14(b) shows. At this time, the ink container is under a downward pressure effected by the configuration of the slanted portion 505a. In a state IV illustrated in Figure 7, the ink container corner P5 is near the end of its travel. At this time, the insertion resisting force is the highest as is evident from Figure 8(b). Then, as the ink container is further inserted, a state VII illustrated in Figure 7 is realized, completing the insertion; in other words, the moment the ink container corner P5 finishes traveling on the slanted portion 505a, it snappily engages with the pressing means 505b. Since the contact surface of the pressing means 505b is horizontal, the feel of resistance having been felt up to this point suddenly disappears at this moment, and this sudden disappearance of the resistance is felt by the user, with his hand, as a feel of the completion of a successful installation. At this time, projections (not shown) provided on the ink container are snappily accelerated toward the internal wall of the casing as they are released, and when they collide with the wall, they generate a "clicking" sound, or a sure feel of clicking, which adds to the feel of the successful completion of the installation. Also at this time, the ink container is pressed downward by the horizontal portion of the pressing means, being surely locked in place. As described above, when the ink container 21 is mounted in an image forming apparatus, the ink delivery member 27Y of the ink container 21 employed in this embodiment of the present invention rubs against the ink reception tube of the image forming apparatus. In the same manner, when the used ink container 21 is mounted in the ink refilling apparatus in this embodiment, and therefore, the ink delivery member 27Y of the used ink container 21 is connected to the ink discharge member 517Y of the ink refilling apparatus, they also rub against each other. As a result, the ink meniscuses 602 and 603 illustrated by the sections of the essential portions of two members in Figure 4 are reliably placed in contact with each other, causing the remaining ink (unillustrated) of the ink container 21 to be united with the ink 510 in the ink chamber 504, and therefore, causing ink refilling to start. In this embodiment, the material for the ink discharge member 517Y of the refilling apparatus and the material for the ink delivery member 27Y of the ink container are selected so that both materials be substantially similar in function or properties. More specifically, "being similar in function or properties" means being similar in wettability by ink, physical strength, or the like. Therefore, both members are formed of the same material, and are rendered the same in length. Further, in this embodiment, the ink discharge member 517Y of the refilling apparatus is rendered smaller in external diameter than the ink delivery member 27Y of the ink container, in order to prevent the ink discharge member 517Y from coming in contact with the internal wall of the ink delivery port of the ink container. This arrangement can prevent the contamination caused by ink adhesion. The density of the ink delivery member 27Y of the ink container is set to render the capillary force of the ink delivery member 27Y larger (for example, -150 mmAq) than that of the porous member of the ink container (generally, -30 mmAq - -100 mmAq) so that ink flow interruption, ink leakage, and the like, can be prevented. On the other hand, the density of the ink discharge member 517Y has only to be high enough to create sufficient capillary force (-50 mmAq or so) to prevent the ink flow in the refilling apparatus from being interrupted. Therefore, the density of the ink discharge member 517Y can be reduced, allowing the external diameter thereof to be reduced without increasing the flow resistance. As a result, refilling time can be reduced. Further, in case the ink delivery member and the ink discharge member are the same in density and material, the following occurs. That is, when the strands of fiber in both members perfectly meet the counterparts, the cross-section of the ink path provided by the bundled strands of fiber becomes largest, but when they completely miss the counterparts, the cross-section of the ink path becomes minimum, that is, almost zero. In other words, rendering them different in density is not rendering the cross-section of the ink path smaller, and can reduce the refilling time. As the aforementioned steps are carried out, the ink 510 within the ink chamber 504 is flawlessly sucked up into the ink container 21 by the negative static pressure generated by the ink retaining porous member 26. The ink chamber 504 is designed so that the distance E between the ink surface 509 and the bottom surface of the ink delivery member 27Y becomes, for example, 20 mm when the ink surface 509 drops to the minimum level required for flawless ink delivery to the ink container. This is due to the characteristic of the static negative pressure of the ink retaining porous member 26. As ink refilling is repeated, the ink within the ink chamber 504 is reduced, which in turn increases the distance E. In order to prevent the negative static pressure from excessively changing, distance D, which is the depth of the ink in the ink chamber 504 is desired to be approximately 10 mm. Therefore, in order to increase the ink capacity of the ink chamber 504, the ink chamber 504 must be designed to be flat as shown in Figure 3. Figure 5 shows the relationship between the amount of ink consumption from the ink container and the negative static pressure P. In the case of an ink container employing an absorbent porous member, the negative static pressure increases as the ink in the ink container is consumed (line I). Then, as the negative pressure reaches a predetermined value (P B ), the ink consumption from the ink container is forced to end (ink flow stops at a point B). Normally, the ink container is mounted in the ink refilling apparatus after the negative static pressure generated by the porous member 26Y holding yellow ink (Y) and the ink delivery member 27Y reaches the point B in Figure 5. As the ink in the ink refilling apparatus is united with the remaining ink in the ink container through the ink delivery member 27Y, the ink stored in the ink chamber 504 is sucked up into the ink container by the negative static pressure P B (Figure 5) generated by the porous member 26Y and the ink delivery member 27Y. While the ink is sucked into the ink container, the negative static pressure at the tip of the ink container changes in the direction indicated by a line H, which is opposite to the negative pressure change (line I) that occurs while ink is consumed from the ink container. In the case of the apparatus described above, even if thee color inks are consumed at different rates, each ink can be refilled to a level at which the aforementioned ink head pressure becomes equivalent to a negative static pressure P E , as long as three color ink refilling apparatuses are initially structured to be equal in the aforementioned ink head pressure, that is, as long as the initial setup satisfies: PY (head pressure of yellow ink) = PM (head pressure of magenta ink) = PC (head pressure of cyan ink). Figure 6 illustrates another embodiment of the ink refilling apparatus in accordance-with the present invention. This apparatus is similar to the apparatus illustrated in Figure 3 except that this apparatus employs a chicken feeder system to keep the ink level on the ink refilling apparatus side substantially constant. Since this ink refilling apparatus and the ink refilling method used in conjunction with this apparatus are the same as those of the ink refilling apparatus illustrated in Figure 3, matters common to both will be omitted and description will be concentrated on the difference. The ink chamber 504 in Figure 6 is provided with an auxiliary ink chamber of a chicken feeder type. The tip of the ink delivery tube of the auxiliary ink chamber is disposed to be in contact with the ink surface 509 of the ink chamber 504. The top wall of the auxiliary ink chamber is provided with an opening, which is kept sealed with a cap 114C while refilling ink into the ink container, and is opened to fill the auxiliary chamber with ink. When refilling the auxiliary ink chamber with ink, the air entrance 502 must be covered with the cap 114C. Otherwise, ink will overflow. Further, the height of the auxiliary ink chamber must be regulated so that ink does not leak from the ink discharge member 517Y. As the ink in the ink chamber 504 is consumed to refill the ink container, the ink surface 509 slightly drops, becoming separated from the tip of the ink delivery tube from the auxiliary ink chamber. As a result, the tip of the ink delivery tube is exposed to the outside air, being allowed to take the outside air into the auxiliary ink chamber. As the outside air enters the auxiliary ink chamber, the ink within the auxiliary ink chamber flows into the ink chamber 504, raising the ink surface 509. Then, as the ink surface 509 rises and comes in contact with the tip of the ink delivery tube, the outside. air is blocked from entering the auxiliary ink chamber through the ink delivery tube. Thus, the level of the ink surface 509 is rendered substantially stable. In other words, according to this embodiment, an ink level sensor is unnecessary (provision of a structure capable of preventing the ink level within the auxiliary ink chamber from dropping to zero level is desirable). As is evident from the description given above with reference to Figure 6, according to this embodiment, it is possible to reliably provide the ink container with the ink head pressure difference necessary when ending the refilling of the ink container, and also, it is possible to stabilize the ink head pressure difference between the ink chamber 504 from which. ink is delivered and the ink container 21 to which ink is delivered. In other words, it is possible to reliably fill the ink container 21 with ink by an amount proportional to the negative pressure generated in the ink container 21 through ink consumption. As described above, the present invention makes it possible to easily and quickly refill the ink container simply by mounting the ink container in the ink refilling apparatus, without the need for a dangerous device such as a hypodermic needle, without causing ink leakage, and without tying up the user for a long time.

Claims: An ink refilling system for refilling ink into an ink container (21), said ink refilling system comprising said ink container (21) and a refilling apparatus (500); wherein said ink container (21) comprises a porous member (26) for retaining the ink, said porous member (26) being capable of inducing a negative pressure in the ink container (21) by consumption of the ink from the ink container (21), and an ink delivery port (28Y) for supplying ink to a recording head detachably mountable to the ink container (21); and wherein said refilling apparatus (500) comprises ink discharging means (504, 506) for retaining additional ink (510) and for supplying the additional ink to the porous member (26) in said container (21), and an ink discharge member (517Y) provided at an ink container connection side of said ink discharging means (504, 506), said ink discharge member (517Y) being capable of absorbing ink and comprising a bundle of unidirectional fibers, characterized in that an ink delivery member (27Y) having a bundle of unidirectional fibers and having a similar wettability as said ink discharge member (517Y) is provided in said ink delivery port (28Y) to contact said porous member (26), wherein, after at least a portion of ink retained by the porous member has been consumed, an ink meniscus (602) in the ink delivery port side of the ink delivery member (27Y) is formed, and in that said refilling apparatus (500) comprises an ink container holding portion (501) for holding the ink container (21), wherein fluid communication between the ink in the ink delivery member (27Y) and the additional ink retained in said discharge means (504, 506) is established by mounting said ink container (21) to said ink container holding portion (501) and contacting said ink delivery member (27Y) and said ink discharge member (517Y) to each other, thereby breaking the meniscus (602) in said ink delivery member (27Y) and a meniscus (603) formed at a contact surface of said ink discharge member (517Y), and thereafter the additional ink is supplied into said ink container (21) by said negative pressure induced in the ink container (21). A system according to Claim 1, wherein said ink delivery member (27Y) and said ink discharge member (517Y) are of the same material. A system according to Claim 1, wherein said ink discharge member (517Y) has a substantially equivalent length to that of said ink delivery member (27Y). A system according to Claim 1, wherein said ink delivery member (27Y) and said ink discharge member (517Y) are slidable relative to each other upon mounting of said ink container (21). A system according to Claim 2, wherein said ink discharge member (517Y) has a density which is smaller than that of said ink delivery member (27Y). A system according to Claim 1, wherein said ink discharge member (517Y) has an outer diameter which is smaller than that of said ink delivery member (27Y). A system according to claim 1, wherein said ink container holding portion (501) retains said ink container (21) in a position such that said ink delivery port (28Y) takes a lower position with respect to the direction of gravity.

Inventors: HIROSAWA TOSHIAKI, KAWAMURA SHOGO, MORITA OSAMU, SATO OSAMU, HIROSAWA, TOSHIAKI, KAWAMURA, SHOGO, MORITA, OSAMU, SATO, OSAMU, HIROSAWA, TOSHIAKI, C/O CANON K.K., Kawamura, Shogo, c/o Canon K.K., MORITA, OSAMU, C/O CANON K.K., SATO, OSAMU, C/O CANON K.K.
Applicants: CANON KK, CANON KABUSHIKI KAISHA
Application year: 1996
Main classification: B41J2
IPC codes: B41J2