Method and apparatus for manufacturing a liquid container having plural porous members

Abstract: The invention provides a method and apparatus for manufacturing a liquid container having an enclosed space within an inner wall of the liquid container, the enclosed space filled with a plurality of porous members (50). The plurality of porous members (50) include a plurality of inner porous members and a plurality of outer porous members. The method includes the step of packing the porous members (50) into the enclosed space so that the inner porous members only contact and press against other inner porous members and/or outer porous members, and the outer porous members contact and press against the inner porous members and the inner wall of the liquid container. The method also comprises a step of compressing the porous members (50). The apparatus has compressing means for compressing the porous members (50) and packing means for packing the porous members (50) into the liquid container. The invention aims to reduce an amount of non-dischargeable liquid contained by the liquid container by packing porous members (50) into the liquid container with a desired compression distribution. The invention also aims to allow the same kind of porous members (50) to be suitably packed into containers that store liquids having different surface tensions, or containers having different capacities or shapes.

Description: BACKGROUND OF THE INVENTION Field of the Invention This invention relates to a method and an apparatus for manufacturing a liquid container having plural porous members for storing a liquid in its internal section and, more particularly, to a method and an apparatus for manufacturing an ink storage container for use in an ink jet recording apparatus. Description of the Related Art Conventionally, ink storage containers for storing ink used in ink jet recording apparatuses are constructed so that a single ink storage foam member having a volume at least approximately equal to the capacity of an ink storage section is disposed in the container body as a high-molecular elastic porous member for storing a liquid, as disclosed in Japanese Laid-Open Publication No. 87242/1988 and Japanese Utility Model Laid-Open Publication No. 692/1993. Such an elastic porous member can stably supply ink if the amount of pores and the compression of the porous member are set to suitable values, as disclosed in, for example, Japanese Patent Laid-Open Publication No. 38816/1993. Accordingly, it is necessary to insert such an elastic porous member into this kind of container with the greatest possible care. As a method for providing an elastic porous material in an ink storage container, a method such as that disclosed in Japanese Patent Laid-Open Publication No. 357046/1992 is known in which an elastic porous material is compressed to a desired size by being pressed with a jig and is thereafter inserted in a container by a piston. A method such as that disclosed in Japanese Patent Laid-Open Publication No. 463/1993 is also known in which a material is compressed along a guide and is thereafter inserted. The above-described packing method is effective in inserting a single porous member in a container. However, it is difficult to insert a plurality of porous members into an ink storage section while uniformly maintaining the porous members in a compressed state in the case of an arrangement such as that disclosed in Japanese Patent Laid-Open Publication No. 245562/1985 or 34353/1990 wherein the ink storage is formed by plural porous members. To improve the ink use efficiency of ink stored in the ink storage section of an ink container, the ink container can be constructed with an ink supply port for supplying ink to an ink outlet formed so as to project into the ink container particularly deforming the porous material incorporated therein. In such a case, since the porous material is deformed in the vicinity of the ink supply port, it is difficult to obtain a desired pressure gradient in a peripheral region where the porous material and the inner wall of the container contact each other. Moreover, in the case of a container which is formed into a complicated shape, e.g., an L-shaped or stepped configuration, it is difficult to insert a porous material uniformly into the container without leaving a gap between the container and the porous material even if the material is formed into a shape similar to that of the container. In such a situation, the ink use efficiency is reduced and an unnecessary space is formed in the container. Further, in the case of containers used for storing ink having different surface tensions or containers having different ink storage chamber capacities, a plurality of elastic porous materials having various pore rates or container-conforming shapes must be used for packing the container. SUMMARY OF THE INVENTION An object of the present invention is to solve the problem that a porous material inserted into a liquid storage container may not be packed so as to have a desired compression distribution, and that the amount of nondischargeable liquid may be increased. Another object of the present invention is to solve the problem that a liquid may accumulate in a space not occupied by a porous material because of the internal shape of the container, and that this accumulated liquid may leak out. Still another object of the present invention is to solve the problem of a need to prepare elastic porous materials having different pore rates or shapes if containers for storing inks differing in surface tension or containers having different capacities or shapes are used. To achieve the above objects there is, in accordance with the present invention a method of manufacturing a liquid container as specified in Claim 1. In accordance with another aspect of the present invention there is an apparatus for manufacturing a liquid container as specified in Claim 17. If the above-described method is adopted, it is possible to set a suitable compression distribution throughout the entire enclosed space of the container. It is also possible to pack the porous members into any shaped container. It is also possible to complete the operation of injecting a liquid into the liquid container at the same time as completing the operations of compressing and packing the porous members into the liquid container. These and other objects, features and advantages of the invention will become more apparent upon a consideration of the following detailed description of preferred embodiments of the present invention taken in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a schematic cross-sectional view of a main casing of a liquid container manufactured in accordance with the present invention; Fig. 2 is a schematic diagram of the liquid container casing viewed in the direction of arrow A in Fig. 1; Fig. 3 is a schematic cross-sectional view of an example of a liquid container manufactured in accordance with the present invention; Figs. 4(a) and 4(b) are schematic cross-sectional views of a porous material packing machine and a liquid container casing, showing an initial stage of a first embodiment of the process of manufacturing a liquid container in accordance with the present invention; Figs. 5(a) and 5(b) are schematic cross-sectional views of the porous material packing machine and the liquid container casing, showing an example of a compressing step in the first embodiment of the liquid container manufacturing process in accordance with the present invention; Figs. 6(a) and 6(b) are schematic cross-sectional views of the porous member packing machine and the liquid container casing, showing an example of steps of packing and compressing the porous member in the first embodiment of the liquid container manufacturing process in accordance with the present invention; Fig. 7 is a schematic cross-sectional view of a porous material packing machine and a liquid container casing, showing a second embodiment of the liquid container manufacturing process in accordance the present invention; Figs. 8(a) through 8(d) are schematic diagrams showing a procedure of packing and compressing the porous members in accordance with the second embodiment of the present invention; Figs. 9(a) through 9(d) are schematic diagrams showing a porous member packing and compressing procedure subsequent to the procedure shown in Figs. 8(a) through 8(d); Figs. 10(a) and 10(b) are schematic cross-sectional views of a packing machine used in a third embodiment of the process of manufacturing a liquid container incorporating high-molecular elastic porous material members in accordance with the present invention; Figs. 11(a) and 11(b) are schematic cross-sectional views of a packing machine used in a fourth embodiment of the process of manufacturing a liquid container incorporating high-molecular elastic porous material members in accordance with the present invention; Fig. 12 is a schematic cross-sectional view of a packing machine used in a fifth embodiment of the process of manufacturing a liquid container incorporating high-molecular elastic porous material members in accordance with the present invention; Figs. 13(a) and 13(b) are schematic cross-sectional views of a packing machine used in a sixth embodiment of the process of manufacturing a liquid container incorporating high-molecular elastic porous material members in accordance with the present invention; and Fig. 14 is a schematic diagram of a conventional liquid container incorporating a high-molecular elastic porous material member. DESCRIPTION OF THE PREFERRED EMBODIMENTS Figs. 1 and 2 show a liquid container which is filled with a porous material by a liquid container manufacturing method in accordance with the present invention. Referring to Fig. 1, the liquid container has a container body 10 and a liquid outlet 8 for discharging a liquid stored in the liquid container. A liquid inducer 10a is provided which serves to improve the effect of discharging the liquid stored in the liquid container. A liquid inducer holding wall 9 is provided to hold the liquid inducer 10a. These components are also illustrated in Fig. 2, showing a view in a direction of arrow A from the container bottom side of Fig. 1. The shape and construction of the container to which the present invention is applied are not limited to those shown in Figs. 1 and 2. The shape of the container may alternatively be such that, in the arrangement shown in Fig. 1, a filter is provided in an end portion of the container surrounded by the liquid inducer holding wall while the liquid inducer 10a is removed. Also, it is not necessary to form the container into the shape of a rectangular parallelepiped having a rectangular cross section as shown in Fig. 2. Fig. 3 shows an example of a liquid container manufactured as an ink tank or the like for use in an ink jet recording apparatus in accordance with the present invention. A member 11 shown in Fig. 3 is a lid for closing an opening through which a porous material is inserted into the liquid container. An atmospheric air vent 11a is formed in the lid 11 to provide an air communication between the interior of the liquid container and the outside air. A plurality of porous flakes of a high molecular elastic material 50 are provided in the liquid container. Each porous flake 50 is formed so as to be sufficiently small in comparison with the capacity of the liquid container. Porous flakes 50 are packed in such a manner that inner porous flakes 50 located, for example, in the vicinity of a center of the container contact only other porous flakes 50, while outer porous flakes 50 located, for example, in the vicinity of the inner wall of the liquid container contact both the inner porous flakes 50 and the inner wall of the liquid container 10b. Porous flake 50 may have any size and shape as long as the porous flakes 50 can be disposed in a row between any inner wall portions of the ink container in opposed positions. The shape of each porous flake 50 is not limited to a particular shape such as the shape of a rectangular prism or a sphere, and plural porous flakes 50 may vary in size and shape. As described above, the means for maintaining a liquid in accordance with the present invention is not a single piece of a porous material having a size such as to generally occupy the entire cavity of the container but plural porous flakes. The porous flakes are packed in the liquid container in such as manner as to contact each other in a compressed state. Preferably, porous flakes 50 are formed with certain degrees of uniformity in size and shape if the liquid container of the present invention is adapted to, for example, an ink jet recording apparatus so as to satisfy a need to supply ink to the ink jet recording apparatus stably and reliably. Processes of manufacturing the above-described liquid container will be described as embodiments of the present invention in detail with reference to the drawings. In each embodiment, each porous flake has a 5 mm square size. (First Embodiment) Figs. 4, 5, and 6 show the first embodiment of the method of manufacturing the liquid container of the present invention. Figs. 4(a) and 4(b) illustrate a process step of supplying a porous flake packing apparatus with porous flakes 50 which are to be packed in the liquid container. Fig. 4(a) is a schematic cross-sectional view of the porous flake packing apparatus, and Fig. 4(b) is a schematic cross-sectional view taken along the line P-P of Fig. 4(a). Figs. 5 and 6 illustrate steps of compressing and packing the porous flakes into the liquid container. Referring to Figs. 4(a) and 4(b), a member 101 is a fitting guide for fitting the liquid container body 10 to the porous flake packing apparatus, and members 102a and 102b are movable plates. Members 1033, 1034, 103bx, 1037, 1038 and 103ax are movable plates for compressing porous flakes along the longitudinal direction of the cross section of the liquid container shown in Fig. 4(b). Members 103ay and 103by are movable plates for compressing porous flakes along a direction perpendicular to the above-mentioned longitudinal direction. Members 1031, 1032, 1035 and 1036 are fixed walls, which also serve as guides for the movements of the movable plates along the above-mentioned two directions. In this embodiment, porous flakes are compressed along the above-mentioned longitudinal direction and are thereafter compressed along the direction perpendicular to the longitudinal direction. However, this order of moving these movable plates to compress the porous flakes may also be reversed by changing the above-mentioned fixed walls 1031, 1032, 1035 and 1036 to movable walls, and changing the moveable members 1033, 1034, 1037 and 1038 to fixed walls. Referring again to Fig. 4(a), members 104a and 104b are movable lids, and a member 105 is a piston for compressing porous flakes in the direction of the height of the liquid container. The movable plates 102a and 102b, the fitting guide 101 and the movable and fixed walls form a chamber for compressing porous flakes. To supply porous flakes to the packing apparatus, one of or both of the movable lids 104a and 104b are moved. An amount of porous flakes to be supplied is determined by a required factor of the liquid container, i.e., capacity, compression, capillary force, etc. The compressing and packing steps will next be described with reference to Figs. 5 and 6. Fig. 5(a) is a schematic cross-sectional view of the porous flake packing machine in a compressing step, and Fig. 5(b) is a schematic cross-sectional view taken along the line P-P of Fig. 5(a). Figs. 6(a) and 6(b) are schematic cross-sectional views of the porous flake packing machine packing and compressing porous flakes in the liquid container respectively. As mentioned above, the movable walls 1033 (not shown), 1034 (not shown), 103bx, 1037 (not shown), 1038 (not shown) and 103ax are moved in the directions of arrows X in Fig. 5(a) for compression along the longitudinal direction of the liquid container shown in Fig. 2. Thereafter, the movable walls 103ay and 103by are moved in the directions of arrows Y in Fig. 5(b), i.e., in the directions along the shorter sides of the cross section of the liquid container shown in Fig. 2, thereby completing the operation of compressing the porous flakes along the two directions. At this time, the members 103ax, 103bx, 103ay and 103by form a packing guide for packing the compressed porous flakes in the liquid container. Piston 105 is then moved in the direction of arrow Z in Fig. 6(a) along with the movable walls 103ax, 103bx, 103ay, and 103by (not shown) forming the packing guide. Also, the movable plates 102a and 102b move laterally in the direction of arrow X' in Fig. 6(a) to enable the packing guide to be inserted into the liquid container. During this operation, the porous flakes are in contact with each other in a compressed state such as to press against the movable walls 103ax, 103bx, 103ay and 103by and, therefore, do not fall into the liquid container. After the packing guide has been fully inserted into the liquid container, the piston 105 is moved in the direction of arrow Z to compress the porous flakes, as shown in Fig. 6(b). Consequently, the porous flakes have now been compressed along three directions consisting of the two horizontal directions and the vertical direction of the liquid container, thereby completing the compressing step. Thereafter, while the piston 105 is being maintained in the state shown in Fig. 6(b), the packing guide is lifted in the direction opposite of arrow Z. After the packing guide has been fully lifted out of the containers, the piston 105 is lifted out of the container. When piston 105 is above the movable plates 102a and 102b, the movable plates move laterally in a direction opposite of arrow X' to complete the step of packing the porous flakes. After the completion of the above-described compressing and packing steps, the lid 11 is affixed to the liquid container by ultrasonic welding or the like, thereby completing the process of manufacturing the liquid container. In the above-described embodiment, the liquid container manufacturing process is used which includes the compressing step of compressing a plurality of porous flakes and the packing step of packing the porous flakes in such a manner that inner porous flakes contact only other porous flakes, whereby the porous material can be packed throughout the entire enclosed space of the liquid container no matter what internal configuration the container has. Further, it is possible to change the capacity and the compression of the liquid container as desired only by changing the amount of porous flakes packed into the container. There is a low probability of the porous flakes being compressed non-uniformly in the liquid container. Accordingly, the problem of an increase in the amount of nondischargeable ink due to a locally high compression of the porous flakes in the liquid container can be substantially overcome. In this embodiment, the liquid outlet portion in which a liquid outlet opening is formed projects into the container, as shown in the conventional arrangement shown of Fig. 14. It is therefore possible to set a compression gradient in the vicinity of the liquid outlet at the time of packing and compressing as shown in Figs. 6(a) and 6(b), respectively. (Second Embodiment) Fig. 7 is a schematic sectional view of a porous material packing machine in the second embodiment of the liquid container manufacturing method of the present invention. Referring to Fig. 7, a hopper 1 for storing porous flakes 50 is provided. A rotary valve 2 serves to check reverse flow of porous flakes 50 and to supply porous flakes 50 at a constant rate. Supply nozzles 5 and 5a are used to insert porous flakes 50 in the liquid container body 10. Porous flakes 50 are transported to the liquid container through a piping 3 serving as supply means of porous flakes 50 from the hopper 1 to the container 10. The piping 3 is provided with an air inlet 4 through which air for transporting porous flakes is introduced into the piping 3. Porous flakes 50 discharged from the hopper 1 through the rotary valve 2 are transported to the supply nozzle 5 through the flexible piping 3 by air pressurized in the direction of arrow D in Fig. 7. Also, other porous flakes 50 are transported from another hopper (not shown) to the supply nozzle 5a. Both the supply nozzles 5 and 5a are inserted into the liquid container body 10 to pack the elastic porous material into the liquid container. Preferably, when the porous material is packed, the interior of the liquid container is decompressed or evacuated by a suitable means to ensure that porous flakes can be suitably inserted into the liquid container. Porous flakes may be transported by a method different from that described above. For example, a method of transporting porous flakes by evacuating or decompressing only the liquid container body may be used. A similar method may also be used in which the liquid container and the piping on the liquid container side as viewed from the hopper 1 are evacuated or decompressed to transport porous flakes. In such a case, decompressed sections may be arranged at a certain number of positions in the piping to set a decompression gradient such that the degree of vacuum is higher at a position closer to the liquid container. Such a transport method is effective in preventing porous flakes from scattering away from the supply nozzle when the liquid container is detached. This transport method reliably controls the rate at which porous flakes are supplied, in comparison with a simple air pressure transport method. A manufacturing process having a step of packing porous flakes and a step of compressing porous flakes in accordance with this embodiment will be described with reference to Figs. 8 and 9. Fig. 8(a) illustrates a state where the supply nozzles 5 and 5a are inserted in the liquid container as shown in Fig. 7. Two supply nozzles are used in this embodiment but the number of supply nozzles is not limited to two. However, if only one supply nozzle is used, it is necessary to control a pressure balance of porous flakes to prevent an increase in the amount of porous flakes 50 above the predetermined amount due to porous flakes 50 falling from the supply nozzle. If two supply nozzles are used as in this embodiment, a supply opening 5k is ordinarily maintained in a closed state, so that porous flakes in the nozzles cannot fall. Therefore, arrangements using two or more supply nozzles of which supply openings face each other such a way to make a pair are more preferable than an arrangement using only one supply nozzle. After the supply nozzles have been inserted into the liquid container, the supply nozzle 5a is first lifted in the direction of arrow D until the opening 5k of the supply nozzle 5 is completely exposed to the inside of the container, as shown in Fig. 8(b). The drive source for lifting the supply nozzle may be, for example, an air cylinder or a ball screw driven by a motor. A ball screw is more preferable if the operations described below are used. A predetermined amount of porous flakes 50 from the supply nozzle 5 is supplied to the container. The predetermined amount of porous flakes supplied in this case is controlled through air pressure and the operation of the rotary valve 2. If it is necessary to control the amount supplied with higher accuracy, a screw type extruder or the like may be used. As shown in Fig. 8(c), the supply nozzle 5a is next moved downward in the direction of arrow E towards the lower end of the supply nozzle 5 compressing porous flakes 50 into a state 50b. The position to which the supply nozzle 5a is moved downward, and which determines the compression of porous flakes 50, is not necessarily set to the lower end of the supply nozzle 5. Ordinarily, with respect to containers used in ink jet recording apparatuses, the compression is set to 3 to 6 times although it may be changed according to the surface tension of ink. To pack porous flakes 50 under the supply nozzle 5, the supply nozzle 5 is lifted until the opening of the supply nozzle 5a is completely exposed to the inside of the container, as shown in Fig. 8(d), and a predetermined amount of porous flakes 50 is supplied from the supply nozzle 5 to the container. Thereafter, the supply nozzle 5 is moved downward until the porous flakes 50 are compressed at the desired compression, as shown in Fig. 9(a). The supply nozzle 5a is then lifted until the opening 5k of the supply nozzle 5 is completely exposed and is then moved downward towards the lower end of the supply nozzle 5 to compress the porous flakes, as shown in Figs. 9(b) and 9(c), as in the case of the steps shown in Figs. 8(b) and 8(c). These steps are successively repeated until a state shown in Fig. 9(d) is established, and the supply nozzles 5 and 5a are thereafter lifted. Thus, in the process of this embodiment, the step of inserting porous flakes and the step of compressing porous flakes are repeated. In this process, before the insertion step is started after the completion of the compressing step, a resilient force acts on compressed porous flakes 50b in the direction parallel to the movement of the supply nozzles to restore the original shape of porous flakes 50. Such a force, however, also acts on adjacent compressed porous flakes 50b in horizontal directions perpendicular to the direction in which each supply nozzle is moved to compress the porous flakes. There is, therefore, no possibility of the shape of the porous flakes being restored to a non-compressed size before the next compressing step is started. After porous flakes 50 have been packed in the liquid container body 10 in the above-described manner, lid 11 having atmospheric air vent 11a is affixed to the liquid container body 10 by ultrasonic welding or the like, as shown in Fig. 3. The liquid container manufacturing process is thereby completed. The compression of porous flakes 50b in the vicinity of the atmospheric vent hole may be reduced slightly by the resilient force acting in the supply nozzle insertion direction. However, the compression in the vicinity of the atmospheric air vent is always lower than the compression in the vicinity of the liquid outlet. Therefore, the influence of the restoration of the porous flakes upon the liquid supply efficiency is small. On the other hand, it is possible that the porous flakes loosened or relaxed from their compressed state will function like a buffer chamber to prevent liquid leaking through the atmospheric air vent. In this embodiment, two nozzles are provided as porous member packing means and porous member compressing means. It is therefore possible to simplify the arrangement of the members needed to be inserted into the container and use the manufacturing apparatus for a smaller liquid container. It is also possible to increase the force for pressing porous flakes along the direction perpendicular to the direction of insertion of the supply nozzles in comparison with the case of using only one supply nozzle. Therefore, the compression adjustment range can be extended. In this embodiment, it is possible to adjust and optimize the process with respect to a change in the container shape or compression only by controlling the porous flake supply rate or the amount of compression applied by the supply nozzles. Increasing the compression of the porous material in the vicinity of the liquid outlet having liquid inducer 10a to improve the ink use efficiency in the liquid container can be achieved by setting the amount of compression applied by the supply nozzles in the vicinity of the liquid outlet. The control of a pressure distribution of this embodiment can be performed more simply and accurately in comparison with the first embodiment. Also, the accuracy with which the ratio of ordinary compression in the liquid container is set can be adjusted by controlling the amount of porous flakes supplied during cycles of the packing and compressing steps. It is therefore possible to achieve a more uniform compression distribution of porous flakes through the entire internal space of the container in comparison with the conventional art. Also, in comparison with the first embodiment, the manufacturing process can be controlled with respect to a wider compression rate range of the liquid container, since the method of loading porous flakes and thereafter compressing the porous flakes is adopted. (Third Embodiment) Figs. 10(a) and 10(b) are schematic sectional views of a porous material packing machine in accordance with the third embodiment of the method of manufacturing the high molecular liquid container of the present invention. Fig. 10(a) shows an initial stage of packing, and Fig. 10(b) shows a state when packing is completed. A hopper 1 is provided in which a feed screw 14 and a compressing screw 15 are incorporated. The feed screw 14 and the compressing screw 15 are connected to a drive shaft 13a of a motor 13 provided outside the hopper 1. The feed screw 14 feeds porous flakes 50 stored in the hopper 1 to the section where the compressing screw 15 is provided. Porous flakes 50 are compressed by the compressing screw 15 to obtain compressed porous flakes 50b. The compression in this case is determined by considering the restoration after the compression of the porous flakes so that the porous flakes are compressed at a desired compression when packed in the liquid container body 10 after being supplied through a transport passage (not shown) from the compressing screw 15. The feed screw 14 and the compressing screw 15 differ from each other in pitch and external configuration. The compressing screw may have a construction in which the diameter of a shaft is constant while the feed pitch of a screw portion is gradually reduced, a construction in which a constant-pitch screw is formed on a tapered shaft the diameter of which is gradually reduced, or a construction based on the combination of the former two types of constructions. Even if only one supply nozzle is used, porous flakes can be prevented from falling at the opening of supply nozzle because the compressed porous flakes are supplied by the compressing screw so that the porous flakes compress each other by pressing the inner wall of the transport passage piping. However, the porous flakes may fall which will depend upon the relationship between the size of the porous flakes and the transport speed. In this embodiment, rotary valve 2 is mounted in the passage from the compressing screw to the supply nozzle 5b to reliably prevent falling. The rotary valve 2 is constructed to transmit the transport pressure by setting the length of blades in the rotary valve to such a value that the blades do not contact the inner surface of the valve. The rotary valve 2 controls the amount of compression applied to the porous flakes and the transport speed or the rate at which porous flakes are supplied. In this embodiment, porous flakes 50b are compressed at several kg/cm 2 on the hopper 1 side of the rotary valve 2 by the compressing screw 15, while on the supply nozzle 5b side they restore their original shape to such an extent as to press against the inner wall of the supply nozzle 5b so that they do not fall because of gravity. Accordingly, by using the rotary valve 2 disposed in the vicinity of the supply nozzle, it is possible to control the porous flake 50 supply rate and amount of compression applied even if the length of the transport piping is long. The operation of this embodiment will now be described. First, the supply nozzle 5b is inserted into the liquid container body 10, as shown in Fig. 10(a). In this state, the motor 13 and the rotary valve 2 are operated to extrude compressed porous flakes 50b from the supply nozzle 5b into the liquid container. While the porous flakes are being extruded, the supply nozzle 5b is lifted in the direction of arrow F to control the compression of porous flakes 50b filling the liquid container body 10 so that the compression is substantially constant. After the container body has been filled with the desired amount of porous flakes as shown in Fig. 10(b), the motor 13 and the rotary valve 2 are stopped and the supply nozzle 5b is further lifted out of the container. The operation of packing porous flakes 50 is thereby completed and a lid is affixed to the liquid container body 10 by ultrasonic welding or the like, as in the case of the second embodiment, thus completing the liquid container. In this embodiment, the supply nozzle 5b is lifted while the compressed porous flakes 50b are extruded. However, there is no need to move the supply nozzle 5b if the height of the liquid container body 10 is small. If the above-described manufacturing method is used, it is possible to pack porous flakes into the entire internal space of the liquid container as well as to optimize the process with respect to the desired container shape and the desired compression. Moreover, the above-described method ensures that porous flakes can be packed more uniformly in comparison with the methods of the first and second embodiments. In the first to third embodiments, no liquid is injected into the liquid container when the liquid container is manufactured. Ink is injected into the liquid container in the form illustrated in Fig. 3. A method may be used to inject ink in which a gas in the container is drawn through the liquid outlet 8 to provide a vacuum or a condition closer to a vacuum in the container, and ink is injected through the liquid outlet 8 with pressure. (Fourth Embodiment) Figs. 11(a) and 11(b) are schematic sectional views of an elastic porous material packing machine in accordance with the fourth embodiment of the liquid container manufacturing method of the present invention. Fig. 11(a) shows an initial stage of packing while Fig. 11(b) shows a state when packing is completed. The construction of the packing machine is similar to that of the third embodiment. However, the construction of this embodiment differs from those described above in that a liquid piping 22 is connected to an intermediate portion of the rotary valve 2, and a filter 23 and a check valve 20 are provided in the piping 22 to prevent compressed porous flakes 50b from flowing into the piping 22 from the rotary valve 2. The operation of this embodiment will be described. Porous flakes 50 pass through the feed screw and the compressing screw while being compressed in the same manner as in the third embodiment. Compressed porous flakes 50b are extruded into the rotary valve 2 and are mixed at the intermediate portion of the rotary valve with a liquid 21 supplied from the liquid piping 22. Ordinarily, if a high molecular elastic porous material having open cells for storing a liquid is immersed in the liquid in a compressed state, the liquid is taken into the high molecular elastic porous material when the compression of the material is moderated. The compression is moderated before and after the rotary valve 2, as mentioned above. Therefore, an arrangement is adopted in which the rotary valve 2 is used as pressure moderating means and the liquid is supplied to the porous flakes at the intermediate portion of the rotary valve 2. The liquid is thereby introduced into porous flakes 50b to obtain liquid-impregnated porous flakes 50c. Thereafter, in the same process steps as in the third embodiment, the liquid container body 10 is filled with liquid-impregnated porous flakes 50c, the supply nozzle 5b is lifted in the direction of arrow F out of the liquid container, and the lid is affixed to the liquid container body 10 by ultrasonic welding or the like, thereby completing the liquid container. While in this embodiment the liquid injection is completed before the porous flake insertion step, the operation of the liquid injection step is performed after the completion of the liquid container in the first to third embodiments. In the first to third embodiments, therefore, the step of evacuating the liquid container and injecting the liquid is provided to cause a sufficient amount of the liquid to permeate into the high-molecular elastic porous material. In this embodiment, the liquid permeates into the porous flakes in the rotary valve 2. Therefore, the liquid container is completely filled with ink when it is filled with the porous material. That is, the step of injecting the liquid during transport from the compressing step to the packing step is combined, so that the total number of steps is reduced and the productivity is improved. (Fifth Embodiment) Fig. 12 is a schematic cross-sectional view of a porous material packing machine in accordance with the fifth embodiment of the liquid container manufacturing method of the present invention. Hoppers 1 and 31 in which feed screws 14, 14b, and compressing screws 15, 15b are incorporated, respectively, are provided. The feed screws 14, 14b and the compressing screws 15, 15b are respectively connected to drive shafts 13a, 16a of motors 13, 16 provided outside the hoppers 1 and 31. The feed screw 14 feeds porous flakes 50 stored in the hopper 1 to the section where the compressing screw 15 is provided. Porous flakes 50b compressed by the compressing screw 15 are supplied to the liquid hopper 31. Liquid 21 to be injected into the liquid container is stored in the liquid hopper 31. Compressed porous flakes 50b having open cells abruptly restore to their original shape so that the liquid permeates into the porous flakes. The feed screw 14b feeds porous flakes 50a thereby impregnated with the liquid to the compressing screw 15b. Liquid-impregnated porous flakes 50a are compressed by the compressing screw 15b to form compressed liquid-impregnated porous flakes 50c. The amount of compression applied by the compressing screw 15b is set by considering the restoration of compressed liquid-impregnated porous flakes 50c so that they are compressed to a desired compression when packed in the liquid container body 10. Compressed liquid-impregnated porous flakes 50c are supplied to the supply nozzle 5b through a piping (not shown). Because the liquid oozes out of compressed liquid-impregnated porous flakes 50c during compression by the compressing screw 15b, a waste liquid nozzle 33 is attached to the compressing section through a filter 32 to discharge the liquid oozing out. In this embodiment, since only one supply nozzle 5b is used, a rotary valve 2 is provided on the upstream side of the supply nozzle 5b for the purpose of preventing porous flakes 50c from falling into the liquid container and ensuring a constant-compression characteristic even though the piping length is large. However, this arrangement need not be exclusively adopted. After packing the porous flakes, the liquid container is completed in the same manner as in the above-described embodiments. In this embodiment, porous flakes 50 are compressed to at a substantially large ratio and are thereafter restored substantially to the initial state. Therefore, the liquid can permeate sufficiently into inner portions of porous flakes 50. If the porous flakes are passed through the liquid hopper 31 several times, they can be impregnated with the liquid more completely. In this embodiment, the porous flakes can be substantially completely restored from the compressed state when impregnated with the liquid. Therefore, the amount of ink absorbed in each porous flake can be larger than that in the fourth embodiment. Accordingly the amount of liquid stored in the liquid container can be increased. (Sixth Embodiment) Figs. 13(a) and 13(b) are schematic sectional views of an elastic porous material packing machine in accordance with the sixth embodiment of the liquid container manufacturing method of the present invention. Fig. 13(a) shows an initial stage of packing while Fig. 13(b) shows a state when packing is completed. In this embodiment, the supply nozzle 5b is formed of a cylindrical pipe 41 and a porous flake pressing member 42 (adjuster). The supply nozzle 5b can be adapted to containers having various shapes by changing the porous flake pressing member 42. In other respects, this embodiment is generally the same as the above-described embodiments. Because the cylindrical pipe 41 smaller in diameter than the piping connected between the hopper 1 and the rotary valve 2 is used, the critical pressing force applied to the wall surface prevent porous flakes 50b from falling is reduced, so that the fall prevention reliability is improved. The arrangement of this embodiment can be applied to any method using only one supply nozzle for supplying porous flakes to the liquid container. (Seventh Embodiment) In the case of manufacturing the liquid container shown in Fig. 3 by one of the above-described manufacturing methods, it is possible that the compression of compressed porous flakes 50b in the vicinity of the atmospheric air vent will be reduced by the resilience force acting toward the lid 11. Therefore, to form the interface between the atmospheric air and the liquid in the vicinity of the atmospheric air vent more positively, this embodiment uses a process step in which the liquid is not supplied to the rotary valve at the time when porous flakes are to be packed in the vicinity of the opening of the liquid container. Thus, porous flakes which are not impregnated with the liquid are packed using the liquid container manufacturing apparatus shown in Fig. 11 in the vicinity of the atmospheric air vent. By this process step, the compression of the porous flakes impregnated with the liquid can generally be made more uniform. Since there is no possibility of the rate of compression of the porous flakes impregnated with the liquid becoming higher than the rate of compression in the vicinity of the liquid outlet, an effect of stabilizing the supply of the liquid particularly at the initial state can be achieved, as well as a buffer effect. In the third to seventh embodiments, supply nozzle 5b is lifted at a constant speed while compressed porous flakes 50b are extruded from supply nozzle 5b, whereby the rate of compression of porous flakes 50b inserted into the liquid container 10 can be made uniform. However, as mentioned above with respect to the second embodiment, there is also a need to increase the compression of porous flakes 50b or liquid-impregnated porous flakes 50c on the liquid inducer 10a side in order to sufficiently discharge the liquid contained in the liquid container so that the operational efficiency of the contained liquid can be improved. In the third to sixth embodiments, an increase or decrease in the compression can be achieved by controlling the apparatus as described below. To gradually increase the compression, the speed at which supply nozzle 5b is lifted while extruding compressed porous flakes 50b or liquid-impregnated porous flakes 50c from supply nozzle 5b is lowered at a position closer to the liquid inducer 10a. To gradually reduce the compression, the speed at which the opening of the supply nozzle is moved is gradually increased. In this manner, the compression of the elastic porous material in the liquid container can be adjusted in accordance with the desired distribution. As described above, it is possible to form a packing density distribution in the container such that the density is higher on the liquid outlet side by controlling the speed at which the porous material is inserted in the container so that insertion speed varies between the charging start point and the inserting completion point. Reliable liquid supply is thereby achieved. In the case of the conventional liquid container storing a high-molecular elastic porous material as shown in Fig. 14, space 10b around liquid inducer 10a in a lower section of liquid container body is not filled with high-molecular porous material 12. A liquid is accumulated in space 10b and can easily leak out of the container, also reducing the amount of liquid contained in the high-molecular porous material 12. In contrast, if one of the porous flake packing methods described above with respect to the first to sixth embodiments of the invention is used, porous flakes 50 can fill the space 10b as shown in Fig. 3, thereby increasing the containable liquid amount as well as preventing leakage. As described above, according to the manufacturing method of the present invention, the porous material to be provided in the liquid container for storing a liquid can be packed so as to have a uniform or a desired compression distribution. It is therefore possible to reduce the amount of the nondischargeable liquid in the container. By using the manufacturing method of the present invention, it is possible to pack the porous material throughout the entire internal space of the container regardless of the internal configuration of the container. There is a low probability of the liquid leaking out of the container. Further, according to the present invention, there is no need to prepare elastic porous members varying in pore rate and shape when containers for storing liquids differing in surface tension or containers differing in capacity or shape are used. Various liquid containers can be manufactured by using the same type of elastic porous member. Further, in the manufacturing method of the present invention, the liquid injection step can be completed along with the porous material packing step and the compressing step. The process for manufacturing the liquid container can therefore be shortened and the productivity can be remarkably improved. While the present invention has been described with respect to what is presently considered to be the preferred embodiments, it is to be understood that the invention is not limited to the disclosed embodiments. To the contrary, the invention is intended to cover various modifications and equivalent arrangements included within the scope of the invention as hereinafter claimed.

Claims: A method of manufacturing a liquid container (10) having an enclosed space within an inner wall of the liquid container (10), wherein the enclosed space is filled with a plurality of porous flakes (50), which are made of high molecular elastic material for storing liquid and include a plurality of inner porous flakes and a plurality of outer porous flakes, said method comprising the steps of: compressing said porous flakes (50) before or while packing; and packing said porous flakes (50) into the enclosed space so that said inner porous flakes only contact and press against other inner porous flakes and/or outer porous flakes, and said outer porous flakes contact and press against inner porous flakes and said inner wall of said liquid container (10) so as to insert said porous flakes (50) uniformly into said container (10) without leaving any gap between said porous flakes (50) or between said container (10) and said porous flakes (50). A method according to claim 1, wherein an amount of compression during the compressing step varies. A method according to claim l, further comprising a step of sealing said liquid container (10). A method according to claim 1, wherein said porous flakes (50) include a plurality of liquid-impregnated porous flakes (50). A method according to claim 1, wherein said compressing step comprises a first substep of compressing said porous flakes (50) in a horizontal direction and in a direction coplanar with and perpendicular to said horizontal direction to provide a packing column with porous flakes (50) and a second substep of compressing the porous flakes (50) in a vertical direction, and said packing step further comprises substeps of inserting said packing column containing porous flakes (50) compressed by said first compressing substep into said liquid container (10) by a packing guide before said second compressing substep is performed and removing said packing guide as to leave the porous flakes (50) in said liquid container (10) after said second compressing substep is completed. A method according to claim 1, wherein said packing step packs a predetermined number of said porous flakes (50) into the enclosed space of said liquid container (10) a plurality of times and said compressing step compresses said porous flakes (50) after each said time. A method according to claim 6, wherein said packing step packs said porous flakes (50) into said liquid container (10) through an opening of at least one packing means by moving at least one packing means in a packing direction. A method according to claim 7, wherein said opening moves at a speed so controlled as to provide a predetermined compression gradient in said porous flakes (50) in said liquid container (10). A method according to claim 7, wherein said compressing step compresses said porous flakes (50) using compressing means comprising at least one packing means moving in a direction opposite to said packing direction. A method according to claim 9, wherein an amount of compression that said porous flakes (50) are compressed in said compressing step is so controlled as to provide a predetermined compression gradient in said porous flakes (50) in said liquid container (10). A method according to claim 71 further comprising a step of transporting through a piping, in which said porous flakes (50) are transported from a storage section where said porous flakes (50) are stored to at least one said packing means by pressurised air. A method according to claim 7, further comprising a step of transporting through said piping, in which the porous flakes (50) are transported from a storage section (1) where the porous flakes (50) are stored to at least one of said packing means by reducing a pressure in said liquid container (10) and in said piping. A method according to claim 1, further comprising a step of controlling an amount of compression of said porous flakes (50), wherein said compression controlling step occurring after said compression step. A method according to claim 13, wherein said compression controlling step is performed by means for controlling a supply rate at which said porous flakes (50) are supplied to said liquid container (10). A method according to claim 13, wherein said compression controlling step further comprises a step of supplying a liquid to said porous flakes (50). A method according to claim 13, wherein the compressing step and the compression controlling step are performed successively for a certain number of times. An apparatus for manufacturing a liquid container (10) having an enclosed space within an inner wall of the liquid container (10), wherein the enclosed space is filled with a plurality of porous flakes (50) which are made of high molecular elastic material for storing liquid and include a plurality of inner porous flakes and a plurality of outer porous flakes, so packed that said inner porous flakes only contact and press against other inner porous flakes and/or outer porous flakes (50) and said outer porous flakes (50) contact and press against inner porous flakes and said inner wall of said liquid container (10); said apparatus comprising: compressing means (103ax, 103ay, 103bx, 103by, 1033, 1034, 1037, 1038) for compressing said porous flakes (50); and packing means (105, 103ax, 103bx, 103ay, 103by) for packing said porous flakes (50) into said liquid container (10), wherein said compressing means also act as said packing means. An apparatus according to claim 17, wherein said compressing means (103ax, 103ay, 103bx, 103by, 105) compress said porous flakes (50) in a horizontal direction, a direction coplanar with and perpendicular to said horizontal direction and a vertical direction. An apparatus according to claim 17, further comprising means (11) for sealing said liquid container (10) filled with compressed porous flakes (50). An apparatus according to claim 18, further comprising; a storage section (1) for storing said porous flakes (50); packing means (5) for packing said porous flakes (50) into said liquid container (10), said packing means having an opening through which said porous flakes (50) are packed, said opening being movable in a packing direction; and a transport means (3) for transporting said porous flakes (50) from said storage section (1) to said packing means (5). An apparatus according to claim 20, further comprising means (2) for controlling a supply rate of said porous flakes (50) to said packing means (5). An apparatus according to claim 20, wherein said packing means (5) also act as said compressing means by moving in a direction opposite of said packing direction. An apparatus according to claim 17, further comprising; feeding means (14) for feeding said porous flakes (50) stored in said storage section (1) to said compressing means; a motor (13) for driving said feeding means and said compressing means; transport means for transporting said porous flakes (50) from said compressing means to said packing means. An apparatus according to claim 23, further comprising means (2) for controlling a supply rate of said porous flakes (50) to said packing means. An apparatus according to claim 24, further comprising means (22) for supplying a liquid to said porous flakes (50). An apparatus according to claim 25, wherein said liquid supplying means (22) supplies said liquid to said porous flakes (50) in said supply rate controlling means. An apparatus according to claim 20 and 23, further comprising; a further storage section (31) for storing a liquid and impregnating said porous flakes (50) with said liquid; a transport means (15) for transporting said porous flakes (50) from said compressing means to said further storage section; a further compressing means (15b) for compressing liquid-impregnated porous flakes (50); further feeding means (14b) for feeding said liquid-impregnated porous flakes (50) to said further compressing means; a further motor (16) for driving said further feeding means and said further compressing means; packing means (5b) for packing said liquid-impregnated porous flakes (50) into said liquid container (10), said packing means having an opening through which said liquid-impregnated porous flakes (50) are packed, said opening being movable in a packing direction; and further transport means (41) for transporting said liquid-impregnated porous flakes (50) from said further compressing means to said packing means. an apparatus according to claim 27, further comprising means (2) for controlling a supply rate of said liquid-impregnated porous flakes (50) to said packing means.

Inventors: HIGUMA MASAHIKO, HINAMI JUN, KOTAKI YASUO, ORIKASA TSUYOSHI, SATO OSAMU, SUGITANI HIROSHI, UJITA TOSHIHIKO, HIGUMA, MASAHIKO, HINAMI, JUN, KOTAKI, YASUO, ORIKASA, TSUYOSHI, SATO, OSAMU, SUGITANI, HIROSHI, UJITA, TOSHIHIKO, HIGUMA, MASAHIKO, C/O CANON K.K., HINAMI, JUN, C/O CANON K.K., KOTAKI, YASUO, C/O CANON K.K., ORIKASA, TSUYOSHI, C/O CANON K.K., SATO, OSAMU, C/O CANON K.K., SUGITANI, HIROSHI, C/O CANON K.K., UJITA, TOSHIHIKO C/O CANON K.K.
Applicants: CANON KK, CANON KABUSHIKI KAISHA
Application year: 1995
Main classification: B41J2
IPC codes: F17C5, B65B1, B65D25, B41J2