Patent Publication Number: US-2015059148-A1

Title: Method for producing liquid storage container

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a method for producing a liquid storage container, and particularly relates to a method for putting, in a storage container, a liquid holding member for holding liquid such as an ink. 
     2. Description of the Related Art 
     As one form of a liquid storage container, an ink tank used in the field of ink jet printing is known. As this ink tank, there is an ink tank in which an ink holding member made of fiber aggregate, a porous body, or the like is impregnated with and holds an ink, as a feature for ensuring a high capability of supplying an ink to a print head without causing ink leakage. 
     The liquid holding member which is impregnated with and holds liquid is generally formed in a larger size than a liquid storage section of the liquid storage container, and compressed when the liquid holding member is put into the storage section. Japanese Patent Laid-Open No. H07-125233(1995) discloses a mechanism for compressing and putting the ink holding member into the ink storage section. More specifically, a compressing jig for compressing the ink holding member is also used as a guide jig for inserting the ink holding member into the storage section, and accordingly, it is possible to omit the step of moving the ink holding member from the compressing jig to the guide jig. As a result, it is possible to prevent the deformation of the holding member such as a wrinkle or a partial separation which may occur as the ink holding member moves. In a case where the wrinkle occurs, an ink may trickle down the wrinkle to cause ink leakage. Further, in a case where the partial separation occurs, the partial separation portion may cause the density of the holding member to increase locally. 
     SUMMARY OF THE INVENTION 
     In a first aspect of the present invention, there is provided a method for producing a liquid storage container comprising the steps of: sticking a plurality of compressing members into a liquid holding member for holding liquid; compressing the liquid holding member by moving the plurality of compressing members; and putting the compressed liquid holding member into a storage section of the liquid storage container and drawing the compressing members. 
     Further features of the present invention will become apparent from the following description of exemplary embodiments (with reference to the attached drawings). 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIGS. 1A to 1C  are views for explaining an inkjet cartridge according to an embodiment of a liquid storage container of the present invention; 
         FIGS. 2A to 2C  are views for explaining a method for putting an ink holding member in an ink storage section according to a first embodiment of the present invention; 
         FIGS. 3A and 3B  are diagrams for explaining a method for compressing an ink holding member of another form according to the first embodiment; 
         FIGS. 4A and 4B  are views for explaining a method for compressing an ink holding member of another form according to the first embodiment; 
         FIGS. 5A to 5E  are views for explaining the step of putting the ink holding member in an ink storage container according to the first embodiment of the present invention; and 
         FIGS. 6A and 6B  are views for explaining the step of compressing an ink holding member according to a second embodiment of the present invention. 
     
    
    
     DESCRIPTION OF THE EMBODIMENTS 
     In the mechanism disclosed in Japanese Patent Laid-Open No. H07-125233(1995), the liquid holding member is put by using the guide jig, and therefore the guide jig itself may cause a wrinkle or a partial separation of the holding member. 
     More specifically, in the case of using the guide jig, it is necessary to compress the holding member into a size which is determined in consideration of the thickness of the guide jig to be inserted as well as the size of the ink storage section. In other words, it is necessary to compress the holding member more for the thickness of the guide jig, and this relatively excessive compression may cause a wrinkle. Further, after the guide jig is inserted into the ink storage section, in either the step of drawing the guide jig from the storage section or the step of pressing and inserting the ink holding member into the storage section, the ink holding member may come into contact with the guide jig to cause a partial separation portion on the surface of the ink holding member. 
     An object of the present invention is to provide a method of producing a liquid storage container capable of suppressing the occurrence of a wrinkle or a partial separation in a liquid holding member when the liquid holding member is put in a storage section. 
     Embodiments of the present invention will be described below in detail with reference to the drawings. 
       FIGS. 1A to 1C  are views for explaining an inkjet cartridge according to an embodiment of a liquid storage container of the present invention. In the inkjet cartridge of the present embodiment, a print head for ejecting an ink and an ink tank (an ink storage container) for storing an ink to be supplied to the print head are integral with each other. As shown in  FIG. 1A , the cartridge mainly comprises a printing element substrate  100 , an electric wiring board  200 , and a support member  300 . The printing element substrate  100 , the electric wiring board  200 , and part of the support member  300  constitute the print head, and the most part of the support member  300  constitutes the ink tank. 
     The printing element substrate  100  constituting the print head comprises an array of a plurality of ejection openings and electrothermal conversion elements corresponding to the ejection openings, and ejects an ink from the corresponding ejection openings by using thermal energy generated by the electrothermal conversion elements. The electric wiring board  200  connects an electric signal between the cartridge of the present embodiment and a printing apparatus in which the cartridge is mounted, whereby the printing element substrate  100  can receive a control signal and print data for ejecting an ink from a control section of the printing apparatus. 
     The support member  300  forms an ink storage section  600  containing an ink holding member  400  (a liquid holding member) and storing an ink held by the ink holding member  400  as shown in  FIG. 1B  and  FIG. 1C  showing an IC-IC line cross-section of  FIG. 1B . The ink holding member  400  is put and compressed into the ink storage section  600  to hold an ink by its capillary force. In this manner, the ink holding member  400  generates apparent negative pressure with respect to the ejection openings of the printing element substrate  100  and the air. The ink holding member  400  is formed in a larger size than the ink storage section  600 . As described later with reference to  FIG. 2  and the like, the ink holding member  400  is compressed to a size smaller than that of the ink storage section  600  and inserted and fixed in the storage section by its restoring force. 
     The ink holding member can be mainly formed of fiber aggregate of polypropylene or the like, polyurethane foam, or the like. In the present embodiment, the fiber aggregate is used. Further, the fiber aggregate of the present embodiment is formed by laminating and thermally treating fiber made of a polypropylene core coated with polyethylene to melt polyethylene and bond the crossing points of the fiber. 
     First Embodiment 
     A first embodiment of the present invention relates to a method of putting the ink holding member in the ink storage section.  FIGS. 2A to 2C  are views for explaining the method of putting the ink holding member in the ink storage section. 
     In this method, a plurality of compressing needles  500  are firstly stuck into the ink holding member  400  to be put in the ink storage section, as shown in  FIG. 2A . Next, as shown in  FIG. 2B , the stuck compressing needles  500  are moved in directions toward the inside of the ink holding member  400  shown by arrows  1 . This causes the ink holding member  400  as a whole to be in a compressed state as shown in  FIG. 2C . While this compressed state is maintained, the ink holding member  400  is inserted into the ink storage section  600  as described later with reference to  FIG. 5 . 
     In a case where the compressing needles are moved with excessively large distances between the compressing needles, a wrinkle may occur between the needles in the holding member. Therefore, it is desirable to stick many compressing needles so that the distances between the compressing needles become small. However, in a case where many needles are stuck to the extent that the needles are in contact with each other, there is a possibility that the ink holding member may be torn during compression and movement. Accordingly, it is desirable to determine the number of stuck compressing needles in consideration of the characteristics of the employed ink holding member. In the present embodiment, compressing needles having an outer diameter of 1.2 mm are stuck at intervals of 5 mm. This can realize compression without wrinkles. 
     In a type of the ink holding member which is formed by laminating fiber as shown in  FIG. 3A , interlayer peeling may occur in a case where a plurality of compressing needles are stuck into the same fiber lamination surface and moved for compression. In this case, interlayer peeling during compression and movement can be prevented by arranging the compressing needles in a zigzag pattern, for example so that adjacent compressing needles are not stuck into the same layer or lamination surface as shown in  FIG. 3B . It should be noted that in the case of an ink holding member of a foam type such as polyurethane foam, such peeling does not occur. 
     Further, as shown in  FIGS. 4A and 4B , the ink holding member after compression may be intentionally provided with a coarse and fine distribution by setting the moving distance of a compressing needle according to the position of the needle. For example, the density can be increased by increasing the moving distance for compression of a portion of the ink holding member  400  around an ink path  800  of the printing element substrate. This makes it possible to efficiently concentrate an ink injected into the holding member near the ink flow path  800  and to increase ink supply efficiency. Incidentally, the shape of the ink holding member before insertion into the ink storage section is not uniform for the arrangement of the compressing needles so that the ink holding member has the above density distribution. This shape is not clearly shown in  FIG. 4A , but a portion having a high density after insertion has a large volume before insertion. In this manner, a portion having a larger volume is moved a larger distance, whereby in a case where the ink holding member after insertion into the storage section is free from compression by the needles and conforms to the shape of the storage section, the ink holding member does not have a uniform density distribution similar to the one before insertion and can have a desired density distribution. 
     Next,  FIGS. 5A to 5E  are sectional views for explaining the step of putting the ink holding member in the ink storage container, according to the present embodiment. 
     Firstly, as shown in  FIG. 5A , the plurality of compressing needles  500  are stuck into the ink holding member  400  before insertion and moved in the directions shown by the arrows  1  in  FIG. 5A  ( FIG. 2B  or  FIG. 4A ) to compress the ink holding member  400 . Next, as shown in  FIG. 5B , the compressed ink holding member  400  is set above the ink storage section  600  of the ink storage container. Then, as shown in  FIG. 5C , the ink holding member  400  is inserted in a compressed state without coming into contact with a wall surface of the ink storage section  600 . In other words, the needles compress the holding member to a size such that the compressed holding member is not in contact with the wall surface of the ink storage section. This can prevent the ink holding member from coming into contact with an inner wall of the storage container or the like during the insertion of the ink holding member into the storage container and can prevent the occurrence of a wrinkle or a partial separation in the ink holding member. 
     Next, as shown in  FIG. 5D , forces applied to the compressing needles  500  in the moving directions are released. This causes the ink holding member  400  to conform to the inner wall of the ink storage section  600 . Further, as shown in  FIG. 5D , while a pressing member  700  presses an upper surface of the ink holding member, the compressing needles  500  are drawn in a direction shown by an arrow  2  in  FIG. 5D  to complete the insertion of the ink holding member ( FIG. 5E ). Thereafter the pressing member  700  is removed and a container cover is attached to complete the ink tank. 
     A producing apparatus can perform the above-described method for producing the ink tank. In this method, a holder is prepared which holds the plurality of needles  500  and which can move the held needles independently. The holder is driven to stick, to a predetermined depth, the plurality of needles having positional relationships shown in  FIG. 2A  into the ink holding member  400  set in a predetermined position. Next, the holder is driven to move the compressing needles as shown in  FIG. 2B  or  FIG. 4A . Further, the ink holding member  400  held and compressed by the holder is aligned with the ink storage section  600  of the storage container held by another holder, and is moved and put into the storage section. Thereafter, while a holder holding the pressing member  700  is driven to cause the pressing member  700  to press the ink holding member  400  as shown in  FIG. 5D , the needle holder is driven to draw the compressing needles  500  from the ink holding member. Further, the holder holding the pressing member is driven to remove the pressing member  700  from the ink holding member. 
     Second Embodiment 
     A second embodiment of the present invention relates to an embodiment using compressing claws in place of the compressing needles of the above-described first embodiment.  FIGS. 6A and 6B  are views for explaining the step of compressing an ink holding member according to this embodiment. 
     As shown in  FIG. 6A , as compressing claws  510 , there are two types of claws, that is, claws  510 A which are rectangular in cross section and claws  510 B which are hooked in cross section. These claws  510 A and  510 B are inserted (stuck) into the ink holding member  400  like the compressing needles  500  of the first embodiment. The claws  510 A and  510 B are moved in directions shown by arrows  10  in  FIG. 6A  to compress the ink holding member  400  as shown in  FIG. 6B . It is desirable that the claws as the compressing members be as thin in cross section as possible as long as their rigidity reaches a desired value. This is intended to reduce, as much as possible, the effects of performing cutting by sticking the claws into the ink holding member. 
     In the present embodiment, the rigidity of the compressing members can be increased by forming the compressing members to be inserted into the ink holding member to be rectangular or hooked in cross section. This makes it possible to avoid a state in which movement of the compressing members is attempted for compression but the compressing members cannot be moved for sufficient compression against the resistance of the holding member depending on the properties of the ink holding member to be put into the ink storage section. 
     Also in the case of using the compressing claws of the present embodiment, it is necessary to be careful of the occurrence of a wrinkle during compression and movement. As a result of verification, it is found that an excellent compressed state without wrinkles can be achieved by using the compressing claws having widths in each side of the ink holding member, the sum of which is equal to or larger than half of the length of the side of the ink holding member. In specific explanation with an example shown in  FIG. 6A , the ink holding member has four sides. The compressing claws are used along each of the four sides. Let the length of one of the four sides of the ink holding member be X. The sum of lengths of the compressing claws along the one side (the sum of the lengths of the four compressing claws in a case of a right side) is equal to or larger than X/2. 
     Incidentally, it is not necessary that all the compressing members be either the needles or the claws. It is possible to use the needles and the paws in combination. 
     OTHER EMBODIMENTS 
     The above-described embodiments relate to a method for producing a container for storing an ink. However, it is natural that application of the present invention is not limited to these embodiments. The present invention can be applied to any type of liquid storage container as long as a liquid holding member can be put into the liquid storage container. 
     While the present invention has been described with reference to exemplary embodiments, it is to be understood that the invention is not limited to the disclosed exemplary embodiments. The scope of the following claims is to be accorded the broadest interpretation so as to encompass all such modifications and equivalent structures and functions. 
     This application claims the benefit of Japanese Patent Application No. 2013-178181 filed Aug. 29, 2013, which is hereby incorporated by reference herein in its entirety.