Patent Publication Number: US-6984030-B2

Title: Ink cartridge and method of regulating fluid flow

Description:
BACKGROUND OF THE INVENTION 
   The present invention relates to an ink cartridge for supplying ink in a proper negative pressure state to a recording head that ejects ink droplets in response to print signals. 
   This invention also involves a method for regulating the flow of fluid from an ink cartridge to an ink jet head. 
   An ink jet recording apparatus is generally configured such that an ink jet recording head for ejecting ink droplets in response to print signals is mounted on a carriage reciprocating in a sheet width direction across a piece of recording paper, and ink is supplied from an external ink tank to the recording head. In case of a small recording apparatus, an ink storage container such as an ink tank is arranged to be removable from the carriage in view of convenience in handling and to facilitate replacement of an exhausted ink tank with a fresh ink tank containing a new supply of ink (or inks, if the tank is a multi-color tank). 
   In order to prevent leakage of ink from the recording head, such an ink storage container generally includes therein a porous member impregnated with ink so that the capillary force of the porous member holds the ink. 
   In addition, there is a tendency for the amount of ink consumed to increase, with time, because the continuing development of improved printers leads to an increased number of nozzle openings in order to keep pace with required improvement in print quality and print speed. 
   In order to accommodate these developments in ink jet printer design, it is preferable to increase the amount of ink that can be stored in the ink storage container, but this leads to an increase in the volume of the porous member. However, in the case where the porous member that holds the ink employs capillary force, the height, i.e. water head, of the porous member is limited, and therefore the bottom area of the ink storage container must be increased in order to increase the container&#39;s volume, causing a problem in which the carriage size and thus entire size of the recording apparatus must be increased. 
   To solve this problem, Japanese Patent Kokai Publication No. Hei. 8-174860 proposes, at paragraphs 0041–0043, and  FIG. 10 , an ink cartridge in which a membrane member deformable by ink pressure is formed at its center with a through-hole to provide a membrane valve seat, and a valve member is provided at a location opposing the membrane valve seat. 
   Also to solve this problem, International Patent Publication No. PCT00/03877 proposes an ink cartridge in which a valve member is formed by injection molding of polymer material having elasticity, a through-hole is formed in a center of the valve member, a back surface of the valve member is pressingly contacted with a sealing member by a spring, and the valve member is moved by a negative pressure acting on the back surface of the valve member so that ink flows out only via the through-hole to an ink supply port. 
   Meanwhile, an ink cartridge having high ink supply performance and which can supply a large amount of ink to a recording head, is needed in order to satisfy the need for such cartridges when used in high speed printing. The most important factor affecting the performance when supplying ink to a recording head is the flow passage resistance within the cartridge. 
   U.S. Pat. No. 4,602,662 describes an externally-controlled valve for use in liquid marking systems. This reference teaches that an inlet and outlet are located on one side of a movable member, and a spring and external vacuum source are located on the other side of the movable member. The patent specifically states that the spring is not used to seal the valve, but rather, is provided only to prevent siphoning, and the external vacuum source serves to keep the valve closed. 
   U.S. Pat. No. 4,971,527 involves a regulator valve for an ink marking system. A diaphragm is pressed between two springs and so serves to dampen pressure pulsations in the ink flowing between an inlet and outlet located on one side of the diaphragm. 
   U.S. Pat. No. 5,653,251 relates to a vacuum actuated sheath valve. While an inlet and outlet are located on the same side of the valve membrane, that membrane itself can perforated, allowing liquid to pass to the other side of the membrane. Moreover, the membrane is stretched over a curved projection, and no spring is used to regulating the valve “cracking” pressure. More specifically, U.S. Pat. No. 5,653,251 discloses a valve structure having a valve member made of an elastically deformable membrane, a convex portion with which the valve member is contactable, and a flow channel formed in the convex portion and closable by the valve member. In the valve structure, negative pressure at the demand side is applied to one surface of the valve member to separate the valve member from the flow channel, to thereby control supply and interruption of the liquid. However, in the valve open state, the area of the valve member receiving the liquid pressure (the pressure-receiving area) is extremely small, meaning that the difference in area between the front and back surfaces of the valve member is large. For this reason, the valve open state cannot be maintained by the small pressure change which results from ink consumption by the recording head. When the valve structure is put into the valve closed state, the pressure-receiving area is extremely large, so that the valve structure is returned to the valve open state. Accordingly, there is a problem in that this operation is undesirably repeated to cause pulsations during the supply of ink, which, it will be appreciated, can adversely affect printing. 
   In the ink cartridge disclosed in International Patent Publication No. PCT00/03877, the through-hole, which forms an ink flow passage through the membrane member, causes a fluidic resistance, and further, a mutual clearance of the through-hole with respect to the valve member cooperating with the through-hole also causes a large fluidic resistance. Thus, it is difficult to supply a large amount of ink to a recording head, which is recently required for high print speed. 
   European Patent Application No. 1 199 178 describes an ink cartridge having a differential pressure valve mechanism (U.S. patent application Publn. No. 2002/0109760 is a counterpart). This reference describes valves in which a perforation in a movable membrane is urged by a spring to abut a solid projection. 
   To reduce the fluidic resistance caused by the through-hole of the membrane member, it is conceivable to make the diameter of the through-hole larger, but since the membrane member must be formed from elastic polymer material, increasing the size of the through-hole will reduce the load per unit area, causing a decrease in the sealing pressure, and thus degrading the valve&#39;s sealing ability and reducing cartridge performance. 
   SUMMARY OF THE INVENTION 
   The present invention was made, in part, in order to solve these problems. 
   An object of the present invention is to provide an ink cartridge that can reduce a flow passage resistance acting on ink in a negative pressure generating structure without degrading sealing ability, to thereby allow a high rate of ink consumption from the ink cartridge by a recording head. 
   Another object of the present invention is to provide an ink cartridge that can be manufactured with excellent yield. 
   Yet another object of the present invention is to provide a fluid flow controller for a recording head, which can reduce a flow passage resistance acting on ink in a negative pressure generating structure without degrading sealing ability, to thereby allow a high rate of ink consumption by the recording head. 
   Still another object of the present invention is to provide an ink cartridge in which a flow passage design is simplified. 
   The present invention provides an ink cartridge, which includes: an ink storage chamber; an ink supply port; and a negative pressure generating mechanism which selectively blocks and opens fluid communication between the ink storage chamber and the ink supply port as a consequence of consumption of ink. The ink negative pressure generating mechanism includes an elastic member having first and second surfaces and a sealing portion, the sealing portion having a through-hole; an ink flow path communicating with the ink supply port and having an opening portion at a position where the sealing portion of the elastic member contacts with and separates from the opening portion, the opening portion facing the through-hole; a communicating portion facing the first surface of the elastic member and communicating with the ink storage chamber; and a space portion facing the second surface of the elastic member and communicating with the ink supply port. 
   The present invention provides a fluid flow controller for a recording head, which includes: an elastic member having a first and a second surfaces and a sealing portion, and movable in response to a pressure differential between the first and second surfaces, the sealing portion having a through-hole; a communicating portion facing the first surface of the elastic member and adapted to communicate with an ink tank storing ink therein; an ink outflow port; an opening portion of an ink flow path, which communicates with the ink outflow port, wherein the sealing portion of the elastic member is arranged for movement into contact with and separation from the opening portion; and a space portion facing the second surface of the elastic member and communicating with the ink outflow port. 
   The present invention provides a method of regulating ink flow from an ink cartridge, having an ink supply port, to an ink jet head. The method includes the steps of: providing, as part of the ink cartridge, a valve chamber having a cover and a base, the base having both an inlet and an outlet, the valve chamber containing an elastic membrane having a through-hole, both the inlet and the outlet being disposed on a first side of the elastic membrane, and a space being defined between a second side of the elastic membrane and the cover; and pressing the elastic membrane toward the base with an applied force so that a contact portion of the elastic membrane seals the outlet and the through-hole from the inlet. When a pressure in the space decreases beyond a given value, a resulting pressure differential across the elastic membrane causes the contact portion of the elastic membrane to move away from the outlet against the applied force, thereby communicating the outlet and the through-hole with the inlet. 
   The present invention provides a negative pressure generating mechanism, which is disposed between an ink storage region and an ink supply port, and has a wall surface having two first and second through-holes for ink flow, and a valve member contacted with and separated from the through-hole by receiving a pressure in an ink supply port side. The valve member has a third through-hole. Ink flowing via the first through-hole is supplied via the second and third through-holes to the ink supply port. 
   The present disclosure relates to the subject matter contained in Japanese patent application No. 2002-329062 (filed on Nov. 13, 2002), which is expressly incorporated herein by reference in their entireties. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is an exploded perspective view showing an ink cartridge according to an embodiment of the present invention as viewed from an ink storing chamber side. 
       FIG. 2A  is a perspective view showing the ink cartridge of  FIG. 1  as viewed from the other surface side, and  FIG. 2B  is a prospective view showing another embodiment of a valve member storing portion. 
       FIG. 3  is a sectional view of the ink cartridge, showing a sectional structure thereof in a vicinity of a negative pressure generating mechanism. 
       FIGS. 4A and 4B  are enlarged sectional views, respectively showing a valve closed state and a valve open state of the negative pressure generating mechanism in the ink cartridge, and  FIG. 4C  is a sectional view showing an ink flow passage from the negative pressure generating mechanism to an ink supply port. 
       FIGS. 5A and 5B  show the flow of ink in the ink cartridge. 
       FIGS. 6A and 6B  are views showing different embodiments of a valve member. 
       FIG. 7  shows another embodiment in which a member defining a region where the negative pressure generating mechanism is installed is formed as a discrete member. 
       FIG. 8  is a perspective view showing the assembly of an ink cartridge according to another embodiment of the present invention, and in particular showing a structure of an opening side of a container main body. 
       FIG. 9  is a perspective view showing the assembly of the ink cartridge, particularly showing a structure of a front surface side thereof. 
       FIG. 10  is a front view showing the opening side of the container main body. 
       FIG. 11  is a front view showing a bottom portion side of the container main body. 
       FIG. 12  is a sectional view showing a region of the container main body, where a negative pressure generating mechanism is assembled. 
       FIG. 13  is a sectional view showing a flow passage part of the container main body from the region, into which the negative pressure generating mechanism is assembled, to an ink supply port. 
       FIG. 14  is an enlarged sectional view showing the region into which the negative pressure generating mechanism is assembled. 
       FIG. 15  is an exploded perspective view showing the assembly of an ink cartridge according to another embodiment of the present invention, particularly showing an opening side of a container main body. 
       FIG. 16  is a sectional view showing a region of the container main body into which a negative pressure generating mechanism is assembled. 
       FIG. 17  is an enlarged sectional view showing the region into which the negative pressure generating mechanism is assembled in an ink cartridge according to another embodiment of the present invention. 
       FIGS. 18A and 18B  are schematic views, respectively showing a valve closed state and a valve open state of a flow path structure a negative pressure generating mechanism in an ink cartridge according to the present invention. 
       FIGS. 19A and 19B  show other embodiments of a flow path structure in the negative pressure generating mechanism in the ink cartridge according to the present invention. 
       FIGS. 20A and 20B  show another embodiment of another embodiment of a flow path structure in the negative pressure generating mechanism in the ink cartridge according to the present invention. 
       FIG. 21  is a sectional view showing another embodiment of the negative pressure generating mechanism. 
       FIG. 22  is a sectional view showing an embodiment of a fluid flow controller for a recording head, which employs the principles of the present invention. 
   

   DESCRIPTION OF THE PREFERRED EMBODIMENT 
   Hereafter, the details of the present invention will be discussed with reference to the illustrated embodiments. 
     FIG. 1  and  FIG. 2A  are exploded perspective views showing an assembly of an ink cartridge according to an embodiment of the present invention, depicting the front and rear structures, respectively.  FIG. 3  is a view showing a sectional structure thereof. The ink cartridge is in part defined by a frame member  2  having openings  1  on both sides thereof, and lid members  3  and  4  sealing the openings  1 , respectively. The ink cartridge is formed with an ink supply port  5  at a leading end side in an insertion direction, e.g. at a bottom surface in this embodiment. The ink supply port according to the present invention encompasses a member or an opening portion to which, or into which, a connection member, such as a hollow needle or pipe, for detachable connection between the ink cartridge and a recording head provided on a carriage, is connectable or insertable. 
   An ink supply flow passage forming member  6 , which is part of a negative pressure generating structure  30  is integrally formed in the vicinity of a portion of the frame member  2  facing the ink supply port  5  so that a portion of the ink supply flow passage forming member  6  located on one opening surface side of the frame member  2  constitutes an opening portion  7 . Opening portion  7  is arranged to be in fluid communication with the ink supply port  5 . 
   The ink supply flow passage forming member  6  is substantially divided into a valve member storing portion  8  for storing a substantially circular (disc-shaped) valve member (called also as an elastic member)  20 , and a flow passage portion  9  for fluid communication with the ink supply portion  5 . A protruding portion  11  having a first through-hole  10  serving as an ink outflow port is formed at a center of the valve member storing portion  8 , and a second through-hole  12  serving as an ink inflow port is formed at a position offset from the protruding portion  11 . The flow passage portion  9  is formed with a third through-hole  13  serving as an ink inflow port for communication with a front surface region of the valve member  20 . 
   As shown in  FIGS. 4A–C , the first through-hole  10  is formed to have a substantially cylindrical straight-sided portion S in an elastic member side, and a funnel-shaped portion R that flares outward moving along the through-hole  10  in the direction of ink flow as the ink moves toward the ink supply port  5 . This funnel-shaped portion R is continuous to and downstream of the straight portion S. That is, the ink outflow side of the through-hole  10  flares outward. This structure ensures reliable sealing by the straight portion S, and lowers the flow passage resistance to fluid movement in the entire first through-hole  10  by the funnel-shaped portion R. 
   A recess portion  15  is formed in a surface  14  of a wall surface  6   a  defining the ink supply flow passage forming member  6  so as to connect the first through-hole  10  of the protruding portion  11  to the third through-hole  13  of the flow passage portion  9 . A communication passage (hereafter, denoted by reference number  15 ′) is defined by sealing the recess portion  15  with a covering film  16 . 
   In the ink supply flow passage forming member  6  thus constructed, the elastically deformable valve member  20  is mounted via a position adjusting frame  21 , as shown in  FIG. 4 . The valve member  20  is provided with a thick portion  20   a  along the circumference thereof, and thick portion  20   a  has a planar surface facing the protruding portion  11 . A spring  22  for adjusting a differential pressure is positioned by a protruding portion  20   b  formed in the center of the valve member  20  and contacts the rear surface (back surface) of the valve member  20 . Further, a holding member  23  seals the outside of the ink supply flow passage forming member  6  in water-tight fashion from an ink storing region while permitting communication between the flow passage portion  9  and the back surface of the valve member  20 . Incidentally, in the depicted structure, the fit between the valve member  20  and the protruding portion  11  can be improved if the mating portions of these elements are made flat, since this will facilitate alignment, and avoid the need to take into account curvature of or irregularities in the abutting surfaces. The valve member  20  is formed with a through-hole  200  passing through the protruding portion  20   b . The through-hole  200  is located within an area of the fit (sealing area) between the valve member  20  and the protruding portion  11 , and is aligned and communicates with the through-hole  10 . 
   To this end, in order to allow for such communication between the flow passage portion  9  and the back surface of the valve member  20 , at least one, and possibly both, of recess portions  9   a  and  23   a  are formed in a region of the ink supply flow passage forming member  6  and the holding member  23  so as to face the flow passage portion  9 . 
   The valve member  20  is preferably made of polymer material, such as an elastomer, which can be formed by injection molding, and which has elastic properties. The valve member  20  is provided with the spring-receiving protruding portion  20   b  at a region facing the protruding portion  11 , i.e. at a central portion thereof 
   A film  24  is joined or attached to a partition wall  6   b  which is part of the ink supply flow passage forming member  6  so as to cover the surface of the holding member  23  and seal the valve storing portion  8  and the flow passage portion  9 , thereby ensuring reliable sealing and separation from the ink storing region. 
   In the embodiment described above, the second through-hole  12  is formed to be of substantially the same size as the first through-hole  10 . However, the present invention is not so limited, and, as shown in  FIG. 2B , the second through-hole  12  may be replaced with a window  12 ′ formed as a consequence of removing a greater portion of the wall surface  6   a , leaving behind enough material to provide a portion that is not deformed due to a pressing force of the spring  22  biasing the valve member  20  and which portion can permit the formation of the recess portion  15  serving as the communication passage. This arrangement thereby provides the same effects as the structure previously described. 
   In this embodiment, when the ink cartridge is mounted to a recording apparatus, and the pressure of the fluid at the ink supply port  5  side, i.e. the most downstream region from which ink is discharged from the ink cartridge, is reduced through ink consumption by a recording head or the like, the liquid pressure in the flow passage portion  9 , the flow passage portion  15 ′ formed by the recess portion  15  and the film  16  and a closed space (called also as a pressure operating compartment)  27  behind the valve member  20  communicating therewith via a flow passage formed by the recess portion  23   a  is also lowered, so that the reduced pressure acts on the surface which is also pressed with a biasing force by the spring  22 . The closed space  27  is in fluid communication with the ink supply port  5  via the passage formed by the recess portion  23   a  and the flow passage  9 . The closed space  27  is also in fluid communication with the ink supply port  5  via the through-hole  200 , the through-hole  10 , the flow passage  15 ′ and the flow passage  9 . However, in the case where the negative pressure of the fluid in the ink supply port  5  does not reach a predetermined valve, the valve member  20  maintains a sealed state of the first through-hole  10  and the through-hole  200  as it is subjected to the biasing force of the spring  22 . 
     FIG. 4C  is a sectional view taken, in part, through the flow passage portion  9  of the negative pressure generating structure  30 . When the negative pressure is decreased so that the correspondingly-generated force is less than the force applied by the spring  22  and the inherent rigidity of the valve member  20 , the negative pressure at the ink supply port  5  acts on the pressure operating compartment  27  of the valve member  20 , which is in communication with the ink supply port through the recess portion  23   a  or  9   a  ( FIG. 4C ) and the through-hole  200 , etc. Accordingly, the valve member  20  experiences a sufficient force from the pressure differential to be moved against the biasing force of the spring  22 , and so is separated from the protruding portion  11  ( FIG. 4B ), allowing ink in the ink storing chamber  17  to flow into the communication passage  15 ′ via the second through-hole  12  (this is depicted by arrow A in  FIG. 5A ) and the first through-hole  10  of the protruding portion  11 . The ink flowing into the communication passage  15 ′ flows via the third through-hole  13  (depicted by arrow B in  FIG. 5A ) and the flow passage portion  9  into the ink supply port  5  (depicted by arrow C in  FIG. 5B ). Concurrently, ink in the ink storage chamber  17  is allowed to flow into the pressure operating compartment  27  via the through-hole  12  and the through-hole  200 . The ink flowing into the compartment  27  flows via the recessed portion  23   a ,  9   a  and the flow passage portion  9  into the ink supply port  5 . 
   When a predetermined quantity of ink flows into the ink supply port  5  in this fashion to increase the pressure at the back surface of the valve member  20 , the change in the pressure differential across the valve member  20  causes the valve member  20  to be elastically contacted with the protruding portion  11  under the biasing force of the spring  22 , and so seal the through-hole  10  and the through-hole  200  ( FIG. 4A ). 
   Thereafter, this operation is repeated to supply ink into the recording head, while maintaining the pressure at the ink supply port side at the predetermined negative pressure. 
   It should be noted that this regulation of the ink flow takes place automatically in response to the consumption of ink from the ink supply port. This avoids the need to have a dedicated external control system which periodically opens and closes the valve to regulate ink flow from the ink container to the ink supply port, and so simplifies and improves the ink cartridge construction. 
   As shown in  FIG. 6A , the sealing side of the valve member according to the present invention is formed as the planar surface. Alternatively, as shown in  FIG. 6B , a protruding portion  28  may be formed to have the through-hole  200  passing therethrough. 
   In the embodiment described above, the valve member and the frame member are constructed as discrete members. However, they may be formed as a one-piece member through coinjection molding with respective appropriate materials. 
   In the embodiment described above, the wall defining the region where the negative pressure generating mechanism is installed is formed to be integral with the member defining the ink storing region. Alternatively, as shown in  FIG. 7 , the member defining the region where the negative pressure generating mechanism is installed may be constructed as a discrete member  31 , which is inserted into an upstream side opening  5   a  of the ink supply port  5 . 
   Next, another embodiment of the present invention will be discussed. 
     FIGS. 8 to 11  show the front and rear structures of an ink cartridge with an opening closure member removed.  FIGS. 12 and 13  show details of a negative pressure generating mechanism that is seen in cross-section.  FIG. 14  shows details of a negative pressure generating mechanism that is seen in enlarged cross-section. With reference now to  FIG. 8 , the interior of a container main body  50  forming an ink storage region is vertically divided by a wall  52  extending substantially in a horizontal direction, and, more specifically, extending so that an ink supply port  51  side of the wall  52  is located slightly downward. A valve member  54 , a sealing member  55  and a spring  53  are stored in the ink supply port  51 , so that in the state where the ink cartridge is not mounted upon a recording apparatus main body, the valve member  54  is kept in elastic contact with the sealing member  55  by the spring  53  to sealingly close the ink supply port  51 . 
   The lower region below the wall  52  is formed with a first ink storage chamber  56 , and the upper region above the wall  52  is defined by a frame  59  having the wall  52  as a bottom surface, and that is separated from a wall  57  of the container main body  50  by a clearance, preferably constant, to form an atmosphere communication passage  58 . The interior region of the frame  59  is further divided by a vertical wall  60  formed at its bottom with a communication port  60   a , so that one of the divided regions (i.e. a right side region in the drawing) serves as a second ink storage chamber  61 , and the other region serves as the third ink storage chamber  62 . 
   A suction flow passage  63  is formed in a region opposing the first ink storage chamber  56  so as to connect the second ink storage chamber  61  and a bottom surface  50   a  of the container main body  50 . The suction flow passage  63  is constructed by forming a recessed portion  64  ( FIG. 9 ) in the front surface of the container main body  50  and sealing this recessed portion  64  with an air impermeable film  104 , to be described later in greater detail. 
   In the third ink storage chamber  62 , an ink supply flow passage forming member  67  is constructed by forming an annular frame wall  65  flush with the frame  59 , and a planar surface  66  dividing the interior of the annular frame wall into front and rear sides. A vertical wall  68  is formed between the lower portion of the frame wall  65  and the wall  52  to define a fourth ink storage chamber  69 . A recessed portion  68   a  for communication is formed in the lower portion of the wall  68 . 
   A partition wall  70  is provided between the fourth ink storage chamber  69  and the frame portion  59  to form an ink flow passage  71 . The upper portion of the ink flow passage  71  communicates with the front surface side of the container main body  50  via a through-hole  72  that can serves as a filter chamber, if desired. 
   The through-hole  72  is defined by a wall  73  continuous with the wall  70  such that the through-hole  72  communicates with the upper end of the ink flow passage  71  via a recessed portion  73   a . The through-hole  72  also communicates via a preferably tear-drop-shaped recessed portion  74  formed in the front surface side, and a communication port  73   b  with the interior of the frame wall  65 . 
   As shown in  FIG. 9 , the lower portion of the ink supply flow passage forming member  67  is connected to the ink supply port  51  via a flow passage constructed from a recessed portion  86  formed in the surface of the container main body  50  and an air impermeable film  104  sealing this recessed portion  86 . The ink supply flow passage forming member  67  has the planar surface  66  and an annular wall  80  that are located in the front surface side of the container main body  50  and that are opposite from the ink storage region, to thereby define a valve member storage portion  81 . The planar surface  66  is formed to have at its approximate center a protruding portion  83  having a through-hole  82 . The protruding portion  83  serves as a sealing portion, and is located in a region opposing a through-hole  200  of the elastic valve member  84 . The planar surface  66  is also formed, at offset positions from the protruding portion  83 , with a communication passage  85  communicating with the front surface of the valve member  84 . 
   The through-hole  82 , in a manner similar to that shown in  FIG. 4A , is constructed by a substantially cylindrical straight portion S located on the elastic member side, and a funnel-shaped portion R that is gradually enlarged in the direction of ink flow toward the ink supply port  51  and which is continuous to and downstream of the straight portion S (that is, the ink outflow side of the through-hole  82  flares outward), whereby a reliable seal is ensured by the straight portion S, while the flow passage resistance in the entire through-hole  82  is reduced by the funnel-shaped portion R. 
   A notched portion  87  is formed in the vicinity of the lower end of the wall  80 , which is connected to the recessed portion  86  extending downwardly toward the ink supply port  51 . The depth of this notched portion  87  is chosen so that the notched portion  87  communicates only with a back surface side of the valve member  84  when the valve member  84  is installed. A wall  88  is formed in the rear surface side opposing the through-hole  82 , i.e. in the upper ink storage region, and this wall which extends toward the upper end of the recessed portion  86  while escaping from the communication passage  85  and also partitions a space from the surrounding region, so that the space is connected via through-hole  89  at a lower end of the wall  88  to the upper end region of the recessed portion  86 . 
   The front surface of the container main body  50  is formed with a narrow groove  90  that meanders to increase the flow passage resistance as much as possible, a wide groove  91  around the narrow groove  90 , and a rectangular recessed portion  92  located in a region opposing the second ink storage chamber  61 . A frame portion  93  is formed in the rectangular recessed portion  92  at a location slightly lower than an opening edge of the recessed portion  92 , and ribs  94  are formed inside the frame portion  93  to be separated one from another. An ink-repellent air permeable film  95  is stretched over and adhered to the frame portion  93  to define an atmosphere communication chamber. 
   As seen in  FIGS. 10 and 11 , a through-hole  96  is formed in the bottom surface of the recessed portion  92  to communicate with a slender region  98  partitioned by a wall  97  formed in the interior of the second ink storage chamber  61 . The other end of the region  98  communicates via a through-hole  99  formed in the region  98 , a groove  108  formed in the front surface of the container main body  50 , and a through-hole  99   a  with a valve storage chamber  101  containing therein an atmosphere communication valve  100  that opens when the ink cartridge is mounted on a recording apparatus. The surface side region of the recessed portion  92  with respect to the air permeable film  95  communicates with one end  90   a  of the narrow groove  90 . 
   The valve storage portion  81  of the container main body  50  is constructed in a manner similar to that for the aforementioned embodiment discussed in connection with  FIG. 1 . As shown in  FIG. 9 , the valve member  84  and the spring  102  are installed in like fashion, the holding member  103  is mounted in the same manner, and the film  104  is attached to cover the front surface of the container main body  50  in the same way. The holding member  103  is formed with a groove  105  communicating with the notched portion  87 , and flow passages  106  and  107  communicating with the back surface of the valve member  84 . 
   Consequently, the recessed portions  74 ,  86  and  105  together with the film  104  form the ink flow passage, and the narrow grooves  90  and  91  and the recessed portion  92  and  108  together with the film form the capillary and the atmosphere communication passage. 
   At the opening side of the container main body  50 , openings of the upper portion ink storage chambers  61 ,  62  and  69  and the opening of the ink supply flow passage forming member  67  are sealed by a film  110  to separate these regions from the lower portion ink storage chamber  56  and the atmosphere communication passage  58 . Thereafter, the lid member  111  is sealingly attached to the container main body  50  to complete the lower portion ink storage chamber  56 . 
   In addition, as shown in  FIGS. 8 and 9 , reference numeral  120  in the drawings designates an identification piece that is used to prevent erroneous mounting of the ink cartridge, and reference numeral  121  designates a memory device that stores ink information, etc. therein, and which is mounted in a recessed portion  122  of the container main body. 
   When the ink cartridge thus constructed is mounted on an ink supply needle communicating with a recording head, the valve member  54  is moved backward by the ink supply needle against the biasing force exerted by the spring  53 , to thereby open the ink supply port  51 . In this state, as the pressure in the ink supply port  51  is lowered as a consequence of ink consumption by the recording head as it effects recording, etc., the reduced pressure acts on the flow passage formed by the recessed portion  86  and the film  104  and on the back surface of the valve member  84  via the notched portion  87 , i.e. on the surface where the valve member  84  receives the pressing force of the spring  102 . If the pressure in the ink supply port  51  is not reduced to less than a predetermined value sufficient to move the valve member  84 , the valve member  84  remains pressed in elastic contact against the protruding portion  83  by the biasing force exerted by the spring  102  to thereby keep closed the through-hole  82 . Therefore, ink does not flow from the ink storage chamber to the ink supply port  51 . 
   When the pressure in the ink supply port  51  (i.e. in a flow passage of the member or opening portion to which or into which the connection member, such as the hollow needle or pipe, for detachable connection between the ink cartridge and the recording head provided on the carriage is connected or inserted) is reduced to the predetermined value as a consequence of continued ink consumption by the recording head, the pressure acting on the back surface of the valve member  84  via the flow passage as described above becomes sufficient to overcome the force exerted by spring  102 , and therefore the valve member  84  is separated from the protruding portion  83 . Consequently, ink flows from the communication passages  85  into a region between the valve member  84  and the planar surface  66  so that the ink flows from the through-hole  82  of the protruding portion  83  via the passage formed by the recessed portion (wall)  88  and the film  110 , the through-hole  89 , the flow passage formed between the recessed portion  86  and the film  104 , and the ink supply port  51  into the recording head of the recording apparatus. Concurrently, ink flowing into the region between the valve member  84  and the planar surface  66  also flows from the through-hole  200  of the valve member  84  via the passage  106 , the passage defined by the recessed portion  105  and the film  104 , the notched portion  87 , the passage defined by the recessed portion  86  and the film  104  and the ink supply port  51  into the recording head of the recording apparatus. That is, ink flows from both sides of the valve member  84  into the ink supply port  51 . 
   When the pressure on the back surface of the valve member  84  is increased as a result of a predetermined amount of ink flowing into the back surface side of the valve member  84 , the valve member  84  is again urged into contact with the protruding portion  83  by the biasing force of the spring  102  to seal the through-hole  82  and the through-hole  200  from the region between the valve member  84  and the planar surface  66 , to thereby block the flow passage. Accordingly, it is possible to maintain the liquid in the ink supply port  51  at a negative pressure sufficient to prevent ink leakage from the recording head, while enabling supply of ink to the recording head. 
   As ink is consumed, the ink in the fourth ink storage chamber  69  flows via the flow passage  71  and the through-hole  72  into the front surface side of the valve member  84 . Further, since the only the first ink storage chamber  56  is opened to the atmosphere, ink in the third ink storage chamber  62  flows into the fourth ink storage chamber  69  via the recessed portion  68   a  as the ink in the fourth ink storage chamber  69  is consumed, and ink in the second ink storage chamber  59  flows into the third ink storage chamber  62  via the recessed portion  60   a  as ink in the third ink storage chamber  62  is consumed. Ink in the first ink storage chamber  56  flows into the second ink storage chamber  61  via the suction flow passage  63  as ink in the second ink storage chamber  61  is consumed. Therefore, the most upstream side ink storage chambers are sequentially emptied earlier, so that ink in the first ink storage chamber  56  is consumed first, then ink in the second ink storage chamber  61  is consumed, and so on. 
     FIG. 15  shows another embodiment in which the ink capacity of the aforementioned ink cartridge is increased. The container main body  50 ′ of this embodiment has the same structure as the container main body  50  of the aforementioned embodiment with the exception that the width W of the container main body  50 ′ is made larger. 
   As a consequence of this modification, since the height of the partition wall  65  of the ink supply flow passage forming member  67  differs from that of the frame  59 ′, a third film  130  is used to seal the opening portion of the partition wall  65  of the ink supply flow passage forming member  67  as shown in  FIG. 16 . 
   In the embodiment shown in  FIGS. 8 to 14 , the front surface of the protruding portion  83  of the ink supply flow passage forming member  67  is several times as large as the diameter of the through-hole  82 . As shown in  FIGS. 16 and 17 , the through-hole  82 ′ and the protruding portion  83 ′ may be each formed with a conical shape, when seen in section, to decrease the flow passage resistance by the enlarging diameter of the through-hole  82 ′ as well as to increase a flow passage region between the valve member  84  and a wall  83   a ′ in the vicinity of the through-hole  82 ′, to thereby further decrease the flow passage resistance. 
   Further, as shown in  FIG. 17 , the surface of the valve member  84 , i.e. the sealing side of the valve member  84 , may be formed as a planar surface similarly to the embodiment shown in  FIG. 6A . 
   Next, the operation of the negative pressure generating structure of the ink cartridge as described previously with reference to  FIGS. 8 to 14  will be further discussed with reference to  FIGS. 18A and 18B , which are schematic diagrams depicting additional simplified structure in accordance with the present invention.  FIGS. 18A and 18B  are schematic diagrams respectively showing a valve closed state and a valve open state with the negative pressure generating structure simplified. For clarity in explanation and in correspondence with the structure of the aforementioned negative pressure generating structure, the same reference numerals are used as were employed in connection with the embodiment shown in  FIGS. 8 to 14 . 
   In the valve closed state shown in  FIG. 18A , the valve member  84  closes the through-hole  82  in response to the biasing force applied thereto by the spring  102 , and so the flow of ink from the ink chamber  62  to the ink supply port is blocked. In this state, as when the ink is consumed by the recording head, the pressure in the ink supply port side is correspondingly reduced, so that the thus reduced pressure acts on the valve member  84  via the communication passage  87  and the flow passage  88 . 
   In this embodiment, the back surface side of the valve member  84  communicating with the communication passage  87  faces a compartment  109  that is located between the valve member  84  and the communication passage  87  and which compartment  109  is open for fluid communication to an exterior via the communication passage  87 . The compartment  109  also communicates with the flow passage  88  via the through-holes  82  and  200 . That is, the compartment  109  serves as the pressure operating compartment for transmitting the pressure change of the ink supply port to the back surface of the valve member  84 . 
   Accordingly, the back surface of the valve member  84  receives the reduced pressure of the ink supply port side over an open wide area. For this reason, due to the difference in pressure between the pressure receiving areas on the front and back surfaces of the valve member  84 , a force is exerted in a direction so as to compress the spring  102 . When the pressure at the ink supply port side is reduced below a pressure set by the spring  102 , the valve member  84  is separated from the protruding portion  83  as shown in  FIG. 18B  to open the openings  82  and  200 , whereby the ink in the ink storing chamber  62  flows from the communication passage  85  via the flow passage  88  and the flow passage  87  into the recording head. That is, the ink in the ink storage chamber  62  flows from both sides of the valve member  84  into the recording head. 
   Therefore, any pressure change at the ink supply port side acts surely on the back surface of the valve member  84  via the ink to prevent the supply of ink from stopping. A large amount of ink can be supplied to the recording head. 
   In the aforementioned embodiment, the back surface side of the valve member  84  is constructed to face and block off the closed space  109  that communicates with the exterior via the communication passage  87 , whereby only ink flowing via the opening  200  into the closed space  109  is allowed to flow via the passage  87  into the ink supply port. However, the invention is not restricted thereto or thereby. For example, as shown in  FIG. 19A  or  19 B, the flow passage  88  for fluid communication between the opening  82  and the ink supply port may be connected to one end of the closed space  109  behind the valve member  84 , so that the back surface region of the valve member  84  serves also as an ink flow passage for ink flowing via the opening  82 . In addition, the vertical arrangement of the valve member  84  as shown in  FIG. 19A  helps to insure any bubble passing through opening  85  will float upward along the valve member to the top of the chamber and not be drawn into openings  82  and  200 . 
   By forming an ink outflow passage  86 ′ that communicates with the pressure operating compartment  109  behind the valve member  84  and that is perpendicular to the surface of the valve member  84 , as shown in  FIG. 19B , it is possible to use the ink cartridge with the valve member  84  in a horizontal orientation. 
   In the aforementioned embodiment, the closed space  109  on the back surface side of the valve member  84  communicates with the ink supply port via the passage  87 . However, the invention is not restricted thereto or thereby. For example, as shown in  FIGS. 20A and 20B , the passage  87  may be omitted, so that the closed space  109  communicates with the ink supply port only via the opening  200 . This modification can simplify the flow passage design of the ink supply flow passage forming member  67 . 
   In addition, taking, for instance, the embodiment shown in  FIG. 4  as an example, the differential pressure adjusting spring  22  is disposed on the back surface of the valve member  20  and urges the valve member  20  so that the valve member  20  is in elastic contact with the protruding portion  11 . The present invention should not, however, be restricted thereto or thereby. For example, as shown in  FIG. 21 , the valve member  20  may be made of elastic material, such as a rubber, and the protruding portion  11  may be relatively projected toward the valve member  20  side beyond a plane P that is formed by the undeformed valve body  20  itself in the protruding portion&#39;s absence. In this case, the valve member  20  can be maintained in elastic contact with the protruding portion  11  through the inherent elasticity of the valve member  20  itself This way, a biasing member, such as the spring  22 , can be dispensed with. 
   Alternatively, the valve body  20  can be biased through the combination of its own deformation against a protruding portion  11  together with a suitably positioned biasing spring. 
   Although the present invention has been described with reference to an ink cartridge that can be detachably mounted to the recording head, the present invention is applicable to an ink tank (an ink cartridge) of a type in which a recording head is fixed to an ink storing member such as the ink tank. In this case, the ink supply port discussed above encompasses a boundary area at which the ink storing member is connected to the recording head, that is, the ink supply port means an ink inflow port or portion of the recording head. 
     FIG. 22  shows an embodiment of a fluid flow controller or a liquid supply device that positively employs the operation principle of the valve member as mentioned above to supply ink to a recording head, while maintaining a negative pressure in the passage  86  from which ink flows to the ink inkflow port  147  of the recording head. In this embodiment, the region immediately upstream of the valve member  84  (that is, the region corresponding to the ink storing chamber  62  of  FIGS. 18A and 18B ) is omitted, and instead, a connection member, such as the hollow needle  140  shown in this embodiment, is provided to construct a valve structure device  141 . The valve structure device  141  is detachably connectable to an external device, such as an ink tank or ink container  142  storing ink therein, via the connection member. 
   The ink container  142  is formed at its lower portion with an ink outflow port  143  that is engageable in liquid-tight fashion with the hollow needle  140 . In the case of a new, unused ink container  142 , a sealing film (not shown) that can be pieced by the hollow needle  140  seals the ink outflow port  143  in order to prevent the leakage of ink. In addition, reference numeral  144  in the drawing designates an annular packing adapted to be elastically contacted with the outer circumference of the hollow needle  140 . Reference numeral  145  designates an atmosphere communication hole. 
   The portions of this invention necessary for the valve member  84  to function as discussed above can be provided in the form of an independent device, i.e. the valve structure device  141 . In this arrangement, the recording head  146  is fixed to the bottom portion of the valve structure device  141 , and the ink inflow port  147  of the recording head  146  is connected to the ink outflow port (the flow passage designated by reference numeral  86 ) of the valve structure device  141 . The ink container  142  can be mounted by inserting the ink container  142  in the direction indicated by arrow A to supply ink to the recording head  146 , and can be replaced by moving and withdrawing the ink container  142  in the opposite direction. 
   In addition, the operation and effect of the valve structure device  141  in this embodiment is the same as the aforementioned embodiments, and therefore the valve structure device  141 , when integrated with the ink container  142 , functions in the same manner as the ink cartridge described above. 
   Although the ink container  142  is directly connected (mounted) to the connection member (the hollow needle  140 ) in the embodiment mentioned above, the same effect can be obtained when the connection member is connected via a tube to an ink cartridge installed in a main body of the recording apparatus. 
   Features and advantages of the embodiments according to the present invention will be summarized as follows: 
   (1) The present invention provides an ink cartridge comprising: an ink storage chamber storing ink therein; an ink supply port communicating with the ink storage chamber; and a negative pressure generating mechanism which is disposed between the ink storage chamber and the ink supply port and which controls supply of ink of the ink storage chamber into the ink supply port The negative pressure generating mechanism including a first ink flow path communicating with the ink supply port; a sealing portion formed with an opening portion communicating with the first ink flow path; an elastic member having a through-hole which corresponds in location to the sealing portion and which can contact with and separate from the sealing portion; a communicating portion provided on a first surface side of the elastic member and communicating with the ink storage chamber; and a space portion provided on a second surface side of the elastic member and communicating with the ink supply port. 
   According to this arrangement, in a case that the elastic member separates from the sealing portion in response to a negative pressure at an ink outflow port, the opening portion of the sealing portion and the through-hole of the elastic member each act as an ink flow passage to supply ink to the ink outflow port with reduced flow passage resistance. Therefore, it is possible to provide an ink cartridge which can be accommodated to large amount of ink consumption at a recording head and which is suitable for high speed printing. 
   (2) In the ink cartridge according to (1), the elastic member separates from the sealing portion in response to lowering of pressure at the ink supply port side, thereby making it possible to supply ink via the opening portion or the through-hole into the ink supply port. 
   According to this arrangement, in a case that the elastic member separates from the sealing portion in response to a negative pressure at an ink outflow port, the opening portion of the sealing portion and the through-hole of the elastic member each act as an ink flow passage to supply ink to the ink outflow port with reduced flow passage resistance. Therefore, it is possible to provide an ink cartridge which can be accommodated to large amount of ink consumption at a recording head and which is suitable for high speed printing. 
   (3) In the ink cartridge according to (1), the elastic member is formed with a protrusion, and the through-hole is formed through the protrusion. 
   According to this arrangement, a large space can be ensured around the protrusion, thereby lowing flow passage resistance caused in association with ink flow. 
   (4) In the ink cartridge according to (1), the negative pressure generating mechanism further includes a second ink flow path through which the space portion communicates with the ink supply port. 
   According to this arrangement, ink flow into the ink supply port can be formed by the first ink flow path and the second ink flow path, and therefore a large amount of ink can be smoothly supplied to the ink supply port. 
   (5) In the ink cartridge according to (1), the space portion communicates with the ink supply port via the through-hole, the opening portion and the first ink flow path. 
   According to this arrangement, the control for the elastic member can be realized by a simple structure, while the increase of flow passage resistance caused in association with ink flow can be suppressed by the opening portion. 
   (6) In the ink cartridge according to (1), the negative pressure generating mechanism further includes a partition wall that is disposed at an upstream side of the elastic member and that defines a compartment between the elastic member and the partition wall, the partition wall having a protruding portion against which the elastic member elastically presses, and the opening portion is formed in the protruding portion. 
   According to this arrangement, in a state in which ink is supplied by separation of the elastic member from the opening portion, a space as large as possible can be ensured around the protruding portion, thereby suppressing dynamic pressure loss associated with ink flow. That is, the protruding portion can be formed by the same material as that of a container main body, a protruding amount (a height) of the protruding portion can be set in an arbitrary manner, and design freedom for a shape of the protruding portion and a shape of the through-hole can be increased. 
   (7) In the ink cartridge according to (6), the negative pressure generating mechanism further includes a biasing member that is disposed opposite to the protruding portion and which urges the elastic member toward the protruding portion. 
   According to this arrangement, the elastic member can be reliably brought into contact with the protruding portion regardless of posture of the elastic member. Therefore, sealing ability can be maintained regardless of movement of a carriage, vibration applied from an exterior, etc. Further, a contact force (a sealing force) by which the elastic member contacts the protruding portion can be easily set to an optimal value, i.e. a value that can prevent separation of the elastic member due to the carriage movement and that can maintain a suitable negative pressure for supplying ink, by adjusting a basing force (an elastic force) of the biasing member. In particular, in a case that a coil spring is used as the biasing member, the adjustment can be made easily and accurately. 
   (8) In the ink cartridge according to (6), the elastic member is urged toward the protruding portion by elastic deformation of the elastic member. 
   According to this arrangement, without increasing the number of component parts, the elastic member can be reliably brought into contact with the protruding portion regardless of posture of the elastic member, and sealing ability can be maintained regardless of movement of a carriage, vibration applied from an exterior, etc. 
   (9) In the ink cartridge according to (6), the opening portion of the protruding portion is disposed to substantially face a center of the elastic member. 
   According to this arrangement, a central region of the elastic member is deformed symmetrically with respect to the center, while keeping a substantially planar shape. For this reason, the opening portion can be reliably sealed to enhance the sealing ability. 
   (10) In the ink cartridge according to (1), the space portion is arranged so that a pressure caused in a downstream side of the elastic member by consumption of ink is applied to a substantially entire area of the second surface side of the elastic member. 
   According to this arrangement, contact/separation of elastic member with/from the sealing portion can be controlled by receiving the pressure change at the ink supply port by a large area, and therefore the opening of the ink flow path can be conducted only by the pressure change suitable for supplying ink. 
   (11) In the ink cartridge according to (1), the first ink flow path is connected via the space portion to the ink supply port. 
   According to this arrangement, ink in the space portion can also be supplied to the ink supply port, and therefore even if an air bubble exists within the space portion, the air bubble can be easily discharged from the space portion. 
   (12) In the ink cartridge according to (1), the first ink flow path connecting the ink supply port to the opening portion branches at an intermediate position to define a branching passage, and the branching passage is connected to the space portion that applies the pressure onto a substantially entire area of the second surface of the elastic member. 
   According to this arrangement, ink can be supplied using a plurality of flow passage, without complicating a flow passage structure in the vicinity of the ink supply port. 
   (13) In the ink cartridge according to (1), the first and the second surfaces of the elastic member contacts ink over a substantially same area. 
   According to this arrangement, a pressure difference can be readily caused between the first surface side of the elastic member and the second surface side thereof, to thereby reliably causing the movement of the elastic member. 
   (14) In the ink cartridge according to (1), the opening portion includes a cylindrical portion located at an elastic member side and an flared portion flaring outward moving along the flared portion in a direction of ink flow toward the ink supply port. 
   According to this arrangement, the elastic member contacts an area of the cylindrical portion, to thereby ensure reliable sealing ability, and the flared portion enlarges an opening area of the opening portion, to thereby reduce flow passage resistance. 
   (15) In the ink cartridge according to (1), at least a contact region of the elastic member, which contacts the sealing portion, is formed as a planar surface. 
   According to this arrangement, the sealing portion and the elastic member can be brought into contact with each other reliably. Further, the alignment of the sealing portion with respect to the elastic member can be easily performed. 
   (16) In the ink cartridge according to (1), the negative pressure generating mechanism further includes a biasing member that presses the through-hole of the elastic member into contact with the sealing portion. 
   According to this arrangement, the elastic member can be reliably brought into contact with the sealing portion regardless of posture of the elastic member. Therefore, sealing ability can be maintained regardless of movement of a carriage, vibration applied from an exterior, etc. Further, a contact force (a sealing force) by which the elastic member contacts the sealing portion can be easily set to an optimal value, i.e. a value that can prevent separation of the elastic member due to the carriage movement and that can maintain a suitable negative pressure for supplying ink, by adjusting a basing force (an elastic force) of the biasing member. In particular, in a case that a coil spring is used as the biasing member, the adjustment can be made easily and accurately. 
   (17) In the ink cartridge according to (1), the first ink flow path is formed by a recessed portion formed in an ink supply flow passage forming member, and a film sealing the recessed portion. 
   (18) In the ink cartridge according to (17), the opening portion is formed by a through-hole formed through the ink supply flow passage forming member. 
   According to these arrangements (17) and (18), the ink flow path and/or the opening portion can be constructed by a simple structure. 
   (19) In the ink cartridge according to (1), the ink cartridge is further constructed by a frame member having the ink supply port, and a lid member sealingly closing an opening surface of the frame member, and a region in which the negative pressure generating mechanism is installed is formed integral with or discrete from the frame member. 
   According to this arrangement, in a case that the installing region is integral with the frame member, the manufacture is easy. The other case that the installing region is discrete from the frame member is suitable for realizing a complicated structure since the installing region and the frame member can be manufactured separately and then assembled together. 
   (20) In the ink cartridge according to (1), the ink storage chamber is divided into an upper ink storage chamber sealed from an atmosphere and a lower ink storage chamber opened to the atmosphere, the upper ink storage chamber communicates with the lower ink storage chamber via a flow passage, and the negative pressure generative mechanism is disposed in a flow passage connecting the upper ink storage chamber to the ink supply port. 
   According to this arrangement, the pressure change applied to the elastic member in the negative pressure generating mechanism can be limited, while taking into account only the pressure change caused due to the change of the ink amount within the lower ink storage chamber. Therefore, there is no need to set the contact force, by which the elastic member contacts the sealing portion, to an excessively large value, and it is possible to provide an ink cartridge, in which a remaining ink amount can be reduced, without setting the contact force to the excessively large value. 
   (21) In the ink cartridge according to (1), the opening portion is constructed as a through-hole formed through a protruding portion having a planar surface portion at a distal end thereof. 
   According to this arrangement, the contact with the elastic member can be realized reliably. 
   (22) In the ink cartridge according to (21), the protruding portion is conical in section. 
   (23) In the ink cartridge according to (22), the opening portion includes a flared portion flaring outward moving along the flared portion in a direction of ink flow toward the ink supply port. 
   According to these arrangements (22) and (23), it is possible to reduce flow passage resistance during ink flow. 
   (24) In the ink cartridge according to (1), the through-hole is formed at a center of the elastic member. 
   According to this arrangement, the elastic member is deformed symmetrically with respect to the center, and therefore the contact with the sealing portion can be made reliable. 
   (25) In the ink cartridge according to (1), the elastic member is shaped as a disc. 
   According to this arrangement, the deformation of the elastic member can be made uniform, and the contact with the sealing portion as well as the deformation when the pressure change occurs can be made reliable. 
   (26) The present invention also provides an ink flow controller comprising: an elastic member having a first and a second surfaces and a through-hole, and movable in response to a pressure differential between the first and second surfaces; a sealing portion having an opening portion which can contact with and separate from the through-hole and which communicates with an ink outflow port; a communicating portion provided on a side of the first surface of the elastic member and adapted to communicate with an ink tank storing ink therein; and a space portion provided on a side of the second surface of the elastic member and communicating with the ink outflow port. 
   According to this arrangement, in a case that the elastic member separates from the sealing portion in response to a negative pressure at an ink outflow port, the opening portion of the sealing portion and the through-hole of the elastic member each act as an ink flow passage to supply ink to the ink outflow port with reduced flow passage resistance. Therefore, it is possible to provide an ink flow controller which can be accommodated to large amount of ink consumption at a recording head and which is suitable for high speed printing. 
   (27) In the fluid flow controller according to (26), a partition wall is disposed at an upstream side of the elastic member to define a compartment between the elastic member and the partition wall, the partition wall having a protruding portion against which the elastic member elastically presses, and the opening portion is formed in the protruding portion. 
   According to this arrangement, in a state in which ink is supplied by separation of the elastic member from the opening portion, a space as large as possible can be ensured around the protruding portion, thereby suppressing dynamic pressure loss associated with ink flow. That is, the protruding portion can be formed by the same material as that of a container main body, a protruding amount (a height) of the protruding portion can be set in an arbitrary manner, and design freedom for a shape of the protruding portion and a shape of the through-hole can be increased. 
   (28) In the fluid flow controller according to (27), a biasing member is disposed opposite to the protruding portion and urges the elastic member toward the protruding portion. 
   According to this arrangement, the elastic member can be reliably brought into contact with the protruding portion regardless of posture of the elastic member. Therefore, sealing ability can be maintained regardless of movement of a carriage, vibration applied from an exterior, etc. Further, a contact force (a sealing force) by which the elastic member contacts the protruding portion can be easily set to an optimal value, i.e. a value that can prevent separation of the elastic member due to the carriage movement and that can maintain a suitable negative pressure for supplying ink, by adjusting a basing force (an elastic force) of the biasing member. In particular, in a case that a coil spring is used as the biasing member, the adjustment can be made easily and accurately. 
   (29) In the fluid flow controller according to (27), the elastic member is urged toward the protruding portion by elastic deformation of the elastic member. 
   According to this arrangement, without increasing the number of component parts, the elastic member can be reliably brought into contact with the protruding portion regardless of posture of the elastic member, and sealing ability can be maintained regardless of movement of a carriage, vibration applied from an exterior, etc. 
   (30) In the fluid flow controller according to (27), the opening portion is disposed to substantially face a center of the elastic member. 
   According to this arrangement, a central region of the elastic member is deformed symmetrically with respect to the center, while keeping a substantially planar shape. For this reason, the opening portion can be reliably sealed to enhance the sealing ability. 
   Although the present invention has been described and illustrated in detail, it is clearly understood that the same is by way of illustration and example only and is not to be taken by way of limitation, the spirit and scope of the present invention being defined only by the terms of the accompanying claims.