Abstract:
An ink cartridge including: an ink chamber storing ink; a communication chamber communicating the ink chamber with the exterior of the ink cartridge; a valve member disposed in the communication chamber such that the valve member is displaceable between a first position to shut off communication between the ink chamber and the exterior, and a second position to permit the communication; a biasing member including a side wall portion surrounding the valve member, and an engaging portion extending inward from an end of the side wall portion and engaging with the valve member, the biasing member normally holding the valve member at the first position but allowing the valve member to be placed at the second position by an elastic deformation of at least one of the side wall portion and the engaging portion, and generating a biasing force to restore the valve member to the first position; and a disengagement preventer which prevents the valve member from disengaging from the engaging portion when the valve member is abnormally operated toward the second position.

Description:
INCORPORATION BY REFERENCE  
       [0001]     The present application is based on Japanese Patent Applications Nos. 2004-359730 and 2004-359742, both filed on Dec. 13, 2004, the contents of which are incorporated herein by reference.  
       BACKGROUND OF THE INVENTION  
       [0002]     1. Field of the Invention  
         [0003]     The invention relates to an ink cartridge for supplying ink to a recording apparatus.  
         [0004]     2. Description of Related Art  
         [0005]     JP-2001-113723 (especially  FIG. 4 ) discloses an ink cartridge for supplying ink to a recording apparatus such as inkjet printer, which cartridge is constructed such that the ink does not leak upon removal of the cartridge from the recording apparatus. This ink cartridge has an ink chamber where the ink is stored, an ink outlet through which the ink is supplied to the exterior, and an ink communication chamber.  
         [0006]     In the ink communication chamber is accommodated a valve member, and in the ink outlet is fitted a tubular packing. The valve member is biased by a compression spring and held in contact with the tubular packing so as to close an ink passage, thereby preventing leakage of the ink from the ink chamber. When the ink cartridge is attached to the recording apparatus, an ink inlet tube disposed on the recording apparatus enters the tubular packing to push the valve member to the side of the ink chamber against the biasing force of the compression spring, so as to open the ink passage and enables ink supply.  
         [0007]     However, in the ink cartridge described above, the displacement of the valve member is realized by use of the compression spring, and thus an internal structure of the ink cartridge using the compression spring is complex. Further, the compression spring is of metal and the ink cartridge can not be discarded as it is. That is, upon disposal of a used ink cartridge, the compression spring should be detached from the ink cartridge to be discarded separately from the other part of the ink cartridge, thereby pushing up the cost of the disposal.  
         [0008]     To solve the above-described problems, the present applicant has proposed to replace the compression spring with a biasing member formed of an elastic material to integrally include an elastic side wall portion that surrounds the valve member and is capable of deforming in a direction of the displacement of the valve member, and an engaging portion that extends inward from an end of the side wall portion to be in contact with a surface of the valve member which surface is opposite to a valve hole. An elastic, contracting force of the side wall portion biases the valve member to a position to close the ink passage or the valve hole.  
         [0009]     The employment of the biasing member enables to omit the compression spring, thereby preventing the internal structure of the ink cartridge from being complex. Further, being formable of an elastic material such as rubber, the biasing member needs not to be detached from the ink cartridge upon disposal of the ink cartridge. Thus, the disposal cost is not increased.  
         [0010]     When the ink cartridge including the biasing member is attached to the recording apparatus, the ink inlet tube disposed on the recording apparatus pushes the valve member as closing the ink passage to displace the valve member by stretching the side wall portion of the biasing member against the elastic biasing force thereof so as to open the ink passage. Hence, a space for allowing expansion of the side wall portion of the biasing member should be provided.  
         [0011]     However, a user may attach the ink cartridge to the recording apparatus in an improper manner or tamper with the ink cartridge, such that the valve member is pushed by an amount larger than a normal amount by which the valve member is expected to be pushed, or in a direction different from a normal direction in which the valve member is expected to be pushed. In the event of this, the side wall portion of the biasing member is stretched excessively, or the engaging portion is deformed into an irregular shape by locally deforming more at a part than the other part, resulting in disengagement of the valve member from the engaging portion of the biasing member, that is, the valve member gets out of the biasing member into the above-mentioned space and become incapable of getting back to a position to close the ink passage in a valve chamber defined inside the biasing member. This causes leakage of the ink from the ink cartridge and evaporation of water or other components from the ink.  
       SUMMARY OF THE INVENTION  
       [0012]     This invention has been developed in view of the above-described situations and it is therefore an immediate object of the invention to provide an ink cartridge including a valve member which can maintain functioning even when the valve member is pushed by an amount larger than a normal amount or in a direction different from a normal direction, in order to prevent leakage of ink from the ink cartridge and evaporation of water and other components from the ink.  
         [0013]     To attain the object, the invention provides an ink cartridge including:  
         [0014]     an ink chamber storing ink;  
         [0015]     a communication chamber communicating the ink chamber with the exterior of the ink cartridge;  
         [0016]     a valve member disposed in the communication chamber such that the valve member is displaceable between a first position to shut off communication between the ink chamber and the exterior, and a second position to permit the communication;  
         [0017]     a biasing member including a side wall portion surrounding the valve member, and an engaging portion extending inward from an end of the side wall portion and engaging with the valve member, the biasing member normally holding the valve member at the first position but allowing the valve member to be placed at the second position by an elastic deformation of at least one of the side wall portion and the engaging portion, and generating a biasing force to restore the valve member to the first position; and  
         [0018]     a disengagement preventer which prevents the valve member from disengaging from the engaging portion when the valve member is abnormally operated toward the second position.  
         [0019]     According to this arrangement, when the ink cartridge is not mounted on a recording apparatus, the valve member is biased in a direction to be held in a first position where the valve member shuts off communication between the ink chamber and the exterior. When the ink cartridge is mounted on the recording apparatus, the valve member is displaced, while stretching the biasing member against a biasing force thereof, to a second position to establish communication between the ink chamber and the exterior.  
         [0020]     Where the valve member is pushed by an amount larger than a predetermined, normal or expected amount upon mounting or attaching of the ink cartridge to the recording apparatus, or in a direction other than a normal, expected direction, the valve member tends to disengage from the engaging portion. According to this invention, however, such disengagement is prevented by the disengagement preventer. Thus, it does not occur that the valve member disengages from the engaging portion and becomes incapable of returning to the first position to shut off the communication between the ink chamber and the exterior, which would otherwise cause leakage of the ink from the ink cartridge or evaporation of water or other components from the ink.  
         [0021]     An ink cartridge according to the invention is not limited to the above-described one that includes the biasing member integrally formed of an elastic material to include the side wall portion and the engaging portion, but the invention is also applicable to an ink cartridge including a biasing member having a structure more general. Further, the invention is applicable to not only a communication chamber on an ink supply side, i.e., an ink communication chamber formed to supply the ink in the ink chamber to the exterior therethrough, but also a communication chamber on an air introduction side, i.e., an air communication chamber formed in the ink cartridge to introduce the outside air into the inside of the ink cartridge therethrough. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0022]     The above and other objects, features, advantages and technical and industrial significance of the present invention will be better understood by reading the following detailed description of preferred embodiments of the invention, when considered in connection with the accompanying drawings, in which:  
         [0023]      FIG. 1  is a schematic view of an inkjet recording apparatus to which an ink cartridge according to a first embodiment of the invention is attached;  
         [0024]      FIG. 2  is a cross-sectional view showing a state before the ink cartridge is attached to the inkjet recording apparatus;  
         [0025]      FIG. 3  is a cross-sectional view showing a state where the ink cartridge is attached to the inkjet recording apparatus;  
         [0026]      FIGS. 4A, 4B ,  4 C and  4 D are respectively a plan view, a side view, a cross-sectional view taken along line A-A in  FIG. 4A , and a bottom view, of a valve member in the ink cartridge;  
         [0027]      FIGS. 5A, 5B  and  5 C are a plan view, a side view, and a bottom view, of another valve member of the ink cartridge;  
         [0028]      FIG. 6  is a cross-sectional view of the ink cartridge illustrating how valve devices including the valve members operate;  
         [0029]      FIG. 7  is another cross-sectional view of the ink cartridge illustrating how the valve devices operate;  
         [0030]      FIG. 8  is a fragmentary cross-sectional view of an ink cartridge according to a second embodiment; and  
         [0031]      FIG. 9  is a fragmentary cross-sectional view of an ink cartridge according to a third embodiment. 
     
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS  
       [0032]     Hereinafter, there will be described several presently preferred embodiments of the invention, by referring to the accompanying drawings.  
         [0033]     Referring to FIGS.  1  to  7 , there will be described an ink cartridge according to the first embodiment. In a schematic view of  FIG. 1 , reference numerals  1  and  2  denote the ink cartridge and an inkjet recording apparatus to which the cartridge is attached.  
         [0034]     The ink cartridge  1  is removably attachable to the ink jet recording apparatus  2  including a printhead  7  for ejecting ink droplets, and stores ink to be supplied to the printhead  7 .  
         [0035]     The ink cartridge  1  includes a casing  1   a  which is a hollow box-like member open in its upper side, and a lid  1   b  closing the upper open side of the casing  1   a . The ink to be supplied to the printhead  7  is stored in an ink chamber  16  (shown in  FIG. 2 ) in the casing  1   a . A plurality of the ink cartridges  1 , each containing ink of one of four colors, namely, cyan, magenta, yellow, and black, are attached to the inkjet recording apparatus  2 .  
         [0036]     The inkjet recording apparatus  2  includes a mounting portion  3  at which each ink cartridge  1  is removably attached, a tank  5  which stores ink as supplied from the ink cartridge  1  via a flexible ink supply tube  4 , the printhead  7  which ejects droplets of the ink stored in the tank  5  onto a recording sheet  6 , a carriage on which the tank  5  and the printhead  7  are mounted and which is reciprocated in a horizontal direction, carriage shafts  9  serving as a guide along which the carriage  8  reciprocates, a feeding mechanism  10  for feeding the recording sheet  6 , and a purging device  11 .  
         [0037]     The mounting portion  3  has a base portion  3   a  and two guide portions  3   b  standing upright from opposite ends of the base portion  3   a . In the base portion  3   a  interposed between the guide portions  3   b , there are disposed a hollow ink inlet tube  12  via which the ink stored in the ink cartridge  1  is drawn into the ink supply tube  4 , and an air supply passage  13  through which air is supplied into the ink cartridge  1 .  
         [0038]     The ink supply tube  4  is connected to an end of the ink inlet tube  12  so that the ink inlet tube  12  is communicated with the tank  5  via the ink supply tube  4 . One of opposite ends of an air supply tube  15  is connected to the air supply passage  13 , and the other end of the air supply tube  15  is communicated with the atmosphere.  
         [0039]     In a surface of the printhead  7  to be opposed to the recording sheet  6 , a plurality of nozzles are arranged. Hereinafter, this surface will be referred to as “the nozzle surface”. By driving an actuator constituted by a piezoelectric element, the ink stored in the tank  5  is ejected in the form of droplets through the nozzles toward the recording sheet  6 . Recording or printing on the recording sheet  6  is performed while the carriage  8  on which the printhead  7  is mounted is being reciprocated.  
         [0040]     The printhead  7  is located above the mounting portion  3  so that the ink inside the nozzles is applied with a negative back pressure due to a head difference between the nozzles and the ink cartridge  1  as attached at the mounting portion  3 .  
         [0041]     The purging device  11  is disposed to be opposed to the printhead  7  at a position outside a recording area, and includes a purge cap  11   a  to cover the nozzle surface of the printhead  7 , a waste ink tube  11   b  in communication with the purge cap  11   a , and the pump  11   c  which sucks the ink from the nozzles via the waste ink tube  11   b.    
         [0042]     When a purging operation is implemented, the carriage  8  is moved to a purging position, and the nozzle surface of the printhead  7  is covered by the purge cap  11   a . In this state, the pump  11   c  is driven to suck bad ink containing bubbles and others and accumulated inside the printhead  7 . The sucked bad ink is drawn via the waste ink tube  11   b  into a waste ink tank (not shown) to be stored therein. Recording and purging is controlled by a central processing unit or a CPU (not shown) in the inkjet recording apparatus  2 .  
         [0043]     Referring now to cross-sectional views of  FIGS. 2 and 3 , there will be described a structure of a joint portion as indicated by reference symbol A in  FIG. 1 , at which the ink cartridge  1  is attached to the inkjet recording apparatus  2 .  FIG. 2  shows a state before the ink cartridge  1  is attached to the inkjet recording apparatus  2 , and  FIG. 3  shows a state in which the ink cartridge  1  is attached thereto.  
         [0044]     The ink cartridge  1  includes the casing  1   a , the lid  1   b , and a cap  1   e . The casing  1   a  has a bottom wall  1   c  and a side wall  1   i  that partially define the ink chamber  16 , and is open at an upper side. The lid  1   b  covers the upper open side of the casing  1   a , and the cap  1   e  caps the bottom wall  1   c  of the casing  1   a . The ink cartridge  1  is formed by fusing and bonding the lid  1   b  and the cap  1   e  to the casing  1   a . Through the cap  1   e  are formed two exposing holes  1   f ,  1   g  through which valve devices  23 ,  24  (described later) are respectively exposed.  
         [0045]     On a lower side of the bottom wall  1   c , there are formed an ink communication chamber  30  and an air communication chamber  50 . The ink in the ink chamber  16  is supplied to the exterior through the ink communication chamber  30 , and the atmospheric air is introduced into the ink chamber  16  through the air communication chamber  50 . The communication chambers  30 ,  50  are respectively partially defined inside tubular wall portions  1   h ,  1   k  that extend from the lower surface of the bottom wall  1   c.    
         [0046]     In the bottom wall  1   c  are formed an ink inlet port  1   d  for communication between the ink communication chamber  30  and the ink chamber  16 , and an air introducing port  1   j  for communication between the air communication chamber  50  and the ink chamber  16 . The air introducing port  1   j  has an internal diameter substantially the same as that of the air communication chamber  50 . On an upper surface of the bottom wall  1   c  at a position corresponding to the air introducing port  1   j , a tubular member  62  extends in the ink chamber  16 .  
         [0047]     Inside the tubular member  62  is defined an internal passage having a first portion  62   a  and a second portion  62   b . The first portion  62   a  of the internal passage extends from the air introducing port  1   j  in a direction into the ink chamber  16  and gradually narrows in this direction in cross-sectional view, and the second portion  62   b  extends substantially straight from the first portion  62   a  further into the ink chamber  16 . The air communication chamber  50  is open in the ink chamber  16  over an ink surface via the first and second portions  62   a ,  62   b  of the internal passage.  
         [0048]     A plurality of ribs  70  are formed continuously from an inner surface of the first portion  62   a  of the internal passage to an upper portion of the air communication chamber  50  that is contiguous with the internal passage, such that each rib  70  extends toward a guide bar  66  of a valve member  65  described later. The number of the ribs  70  is three or more. A distance T 1  between a lower end surface  70   a  of each rib  70  and an engaging portion  73  of a biasing member  63  (described later) is determined such that when the ink cartridge  1  is attached to the inkjet recording apparatus  2  as shown in  FIG. 3 , the engaging portion  73  is spaced from the lower end surface  70   a  of the rib  70  with a clearance smaller than the distance T 1  therebetween.  
         [0049]     On an inner surface of the ink communication chamber  30 , there is formed a predetermined number of ribs  71  extending from a lower surface of the bottom wall  1   c  toward an engaging portion  37  of a biasing member  46  and accommodated in the ink communication chamber  30  as described later. The number of the ribs  71  is three or more. A distance T 2  between a lower end surface  71   a  of each of the ribs  71  and the engaging portion  37  is determined such that when the ink cartridge  1  is attached to the inkjet recording apparatus  2  as shown in  FIG. 3 , the engaging portion  37  is spaced from the lower end surface  71   a  of the rib  71  with a clearance smaller than the distance T 2  therebetween.  
         [0050]     Valve devices  23 ,  24  are disposed in the ink and air communication chambers  30 ,  50 , respectively. Hereinafter, the side associated with the ink communication chamber  30  may be referred to as “the ink supply side”, while the side associated with the air communication chamber  50  may be referred to as “the air introduction side”. The valve device  23  on the ink supply side includes the biasing member  46  integrally formed of elastic material, and a valve member  54  of resin. An outer shape of the biasing member  46  is substantially cylindrical. The biasing member  46  includes a valve seat portion  46   a , a biasing portion  46   b  on a side of the valve seat portion  46   a  near the ink chamber  16 , and an attaching portion  33  around the valve seat portion  46   a , that  46   a ,  46   b ,  33  are integrally formed. The valve member  54  is accommodated in a valve chamber defined inside the biasing portion  46   b  and biased by the biasing portion  46   b  in a direction to be held in contact with the valve seat portion  46   a.    
         [0051]     An outer diameter of the attaching portion  33  is larger than that of the biasing portion  46   b . The ink communication chamber  30  has an enlarged portion  44  where the diameter of the ink communication chamber  30  is larger than the other part. The attaching portion  33  is fitted in this enlarged portion  44 . The biasing member  46  is fixed in position with the attaching portion  33  held between the inner surface of the ink communication chamber  30  and the cap  1   e.    
         [0052]     The valve seat portion  46   a  has a through-hole formed at a center thereof. The through-hole includes an upper portion  41 , an insertion portion  35  under the upper portion  41 , and a tapered guide passage  40  under the insertion portion  35 . The insertion portion  35  is formed in a size to allow fitting insertion of the ink inlet tube  12  when the ink cartridge  1  is attached to the mounting portion  3 .  
         [0053]     The biasing portion  46   b  includes a cylindrical side wall portion  36  standing from a circumference of the valve seat portion  46   a  toward the ink chamber  16 , and the engaging portion  37  extending from the side wall portion  36  inward, namely, to a side of the valve member  54  near the ink chamber  16 . The engaging portion  37  has at its center an opening  37   a , whose diameter d 1  is smaller than a diameter d 2  (shown in  FIG. 4C ) of a protrusion  57   a  (described later) of the valve member  54 .  
         [0054]     The biasing portion  46   b  biases the valve member  54  toward the valve seat portion  46   a , by an elastic force of the side wall portion  36  and the engaging portion  37 . Normally, the valve member  54  is held in close contact with the valve seat portion  46   a . When the ink inlet tube  12  is inserted into the insertion portion  35 , the ink inlet tube  12  pushes the valve member  54  toward the ink chamber  16 , and the pushed valve member  54  in turn pushes the engaging portion  37  upward with the side wall portion  36  stretched, thereby forming a clearance between a lower surface of the valve member  54  and the valve seat portion  46   a  so as to allow passage of the ink.  
         [0055]     According to the present embodiment where the biasing member  46 ,  63  is integrally formed to include the valve seat portion  46   a ,  63   a , the side wall portion  36 ,  72 , and the engaging portion  37 ,  73 , the number of components can be reduced, thereby enabling to simplify a production process of the ink cartridge  1 . Further, since the valve seat portion  46   a ,  63   a  is formed of an elastic material, sealability between the valve seat portion  46   a ,  63   a  and the valve member  54 ,  65  ( 68 ) is improved, thereby making it possible to reliably shut off communication between the ink chamber  16  and the exterior of the ink cartridge  1  when the valve member  54 ,  65  ( 68 ) is in contact with the valve seat portion  46   a ,  63   a.    
         [0056]     As shown in  FIGS. 4A-4D , the valve member  54  includes a bottom portion  57 , a cylindrical side wall portion  56  extending perpendicularly upward from a circumference of the bottom portion  57 , and a communication passage  58  continuously formed from the bottom portion  57  to the side wall portion  56 . The bottom portion  57  has the protrusion  57   a , which is annular, at a side thereof opposed to the valve seat portion  46   a . The protrusion  57   a  is formed radially inside of the communication passage  58 , but on an outer side of an open end of the upper portion  41  or the through-hole formed in the valve seat portion  46   a . With the valve member  54  pressed by the biasing portion  46   b  onto the valve seat portion  46   a , the protrusion  57   a  of the valve member  54  elastically deforms and closely contacts an upper surface of the valve seat portion  46   a . The diameter d 2  (shown in  FIG. 4C ) of the protrusion  57   a  is larger than the diameter d 1  (shown in  FIG. 2 ) of the opening  37   a  formed at the center of the engaging portion  37 .  
         [0057]     Similarly to the valve device  23  on the ink supply side, the valve device  24  on the air introduction side includes a biasing member  63  integrally formed of an elastic member, and a valve member  65  of resin. The biasing member  63  is similar to the biasing member  46  of the ink supply side, that is, the biasing member  63  includes a valve seat portion  63   a , a biasing portion  63   b , an attaching portion  63   e , that are integrally formed. The biasing portion  63   b  is similar to the biasing portion  46   b  of the ink supply side, and includes a cylindrical side wall portion  72  standing upright from a circumference of the valve seat portion  63   a  toward the ink chamber  16 , and the engaging portion  73  extending from the side wall portion  72  inward, namely, to a side of the valve member  65  near the ink chamber  16 . The engaging portion  73  has at its center an opening  74 , whose diameter d 3  (shown in  FIG. 2 ) is smaller than a diameter d 4  (shown in  FIG. 5C ) of a protrusion  157   a  (described later) of the valve member  65 . The functions of the respective parts of the biasing member  63  are the same as those of the biasing member  46  at the ink supply side, and description thereof is dispensed with.  
         [0058]     The valve seat portion  63   a  has a through-hole  63   c , through which an operating portion  67  (described later) of the valve member  65  is inserted. Under the valve seat portion  63   a , a cylindrical sealing portion  63   d  is integrally formed to around an open end of the through-hole  63   c.    
         [0059]     As shown in  FIGS. 5A-5C , the valve member  65  includes a guide bar  66  at its upper side, the operating portion  67  at its lower side, and a valve portion  68  substantially at its middle portion. Similarly to the valve member  54  shown in  FIGS. 4A-4D , the valve portion  68  includes a bottom portion  157 , a side wall portion  156 , a communication passage  158 , and a protrusion  157   a  on a lower surface of the bottom portion  157 . The valve portion  68  is similar in structure as the valve member  54 , and the parts or elements corresponding to those of the valve member  54  will be denoted by the same reference numerals and description thereof is omitted. That is, at the air introduction side, the valve portion of the valve member  65  corresponds to a valve member as defined in the appended claims.  
         [0060]     The guide bar  66  is cylindrical and stands upright from the bottom portion  157 . The guide bar  66  is inserted through the opening  74  of the biasing portion  63   b  with a clearance between the guide bar  66  and an inner circumferential surface of the opening  74 , such that the guide bar  66  is located at a position to be surrounded by the ribs  70 .  
         [0061]     The operating portion  67  is a part vertically or downward extending from the bottom portion  157 , through the through-hole  63   c  formed in the valve seat portion  63   a  with a clearance between an inner circumferential surface of the through-hole  63   c  and the operating portion  67  to allow passage of the air.  
         [0062]     In the mounting portion  3  at which the ink cartridge  1  is attached, the ink inlet tube  12  protrudes on the ink supply side, and an elastic porous material  3   c  such as sponge material is embedded around a lower base portion of the ink inlet tube  12 . The elastic porous material  3   c  is disposed there to absorb ink leaking from the ink cartridge  1 , although such ink leakage is to be prevented by the arrangement according to the present invention. That is, the elastic porous material  3   c  is disposed to provide for some extreme situations.  
         [0063]     A communication opening  12   a  in the form of a cutout is formed at an upper end of the ink inlet tube  12  so as to communicate, in a radial direction of the ink inlet tube  12 , an internal passage formed inside the ink inlet tube  12  and a space around the ink inlet tube  12 . When the ink inlet tube  12  is brought into contact with the valve member  54 , the communication opening  12   a  ensures communication between the internal passage defined in the ink inlet tube  12  and the ink chamber  16 .  
         [0064]     At the air introduction side of the mounting portion  3 , a recess  3   d  is formed at a position corresponding to the sealing portion  63   d  of the biasing member  63  of the ink cartridge  1 . In the recess  3   d , the air supply passage  13  is open at a position not to be completely covered by a lower end of the operating portion  67 . When the ink cartridge  1  is attached on the mounting portion  3  as shown in  FIG. 3 , the sealing portion  63   d  is fitted in the recess  3   d  with an end portion of the sealing portion  63   d  elastically deformed to be held in close contact with a bottom of the recess  3   d , thereby establishing sealed communication between the air supply passage  13  and the air introducing port  1   j.    
         [0065]     Referring to  FIGS. 2 and 3 , there will be described a state when the ink cartridge  1  is attached to the mounting portion  3 . Before the ink cartridge  1  is attached to the mounting portion  3 , as shown in  FIG. 2 , at the air introduction side the operating portion  67  protrudes downward from the cap  1   e  with a lower end of the operating portion  67  located slightly above an extreme lower end of the sealing portion  63   d , and the valve member  65  is biased by the biasing portion  63   b  to be held in close contact with the valve seat portion  63   a . Meanwhile, at the ink supply side the valve member  54  is biased by the biasing portion  46   b  to be held in close contact with the valve seat portion  46   a.    
         [0066]     When the ink cartridge  1  is attached on the mounting portion  3  as shown in  FIG. 3 , at the ink supply side an upper end of the ink inlet tube  12  pushes the valve member  54  upward, thereby stretching the side wall portion  36  of the biasing portion  46   b  so that the valve member  54  separates away from the valve seat portion  46   a , placing the valve device  23  in an open state where the valve member  54  is at a first position to permit communication between the ink chamber  16  and the exterior of the ink cartridge. Hence, the ink stored in the ink chamber  16  is supplied into the ink inlet tube  12  via the ink inlet port  1   d , the ink communication chamber  30 , the opening  37   a  formed in the engaging portion  37 , the communication passage  58  (shown in  FIGS. 4A-4D ) in the valve member  54 , and the communication opening  12   a  at the end of the ink inlet tube  12 .  
         [0067]     Meanwhile, at the air introduction side, in a state where an end of the operating portion  67  is held in contact with the bottom of the recess  3   d  to fix the valve member  65  in position, the valve seat portion  63   a  of the biasing member  63  is displaced downward relatively to the valve member  65 , in other words, the valve member  65  is pushed upward relatively to the valve seat portion  63   a , with the side wall portion  72  of the biasing portion  63   b  stretched so that the valve member  65  separates away from the valve seat portion  63   a , thereby placing the valve device  24  in an open state where the valve member  65  is placed in a first position to communicate the inside of the ink cartridge with the exterior thereof. The guide bar  66  of the valve member  65  moves along vertically extending end surfaces of the ribs  70  which surfaces are opposite to an inner surface of the air introducing port  1   j , such that even when a direction in which the valve member  65  is pushed deviates from an exactly vertical direction which is a normal direction in which the valve member  65  is expected to move by being pushed (hereinafter, the normal direction in which the valve member  65  is expected to be pushed may be referred to as “the normal direction in which the valve member  65  is expected to move”), the deviation is limited by the ribs  70  that make the valve member  65  move in a substantially vertical direction. That is, the vertically extending end surfaces of the ribs  70  correspond to a guiding portion. Thus, the side wall portion  72  is stretched substantially uniformly over an entire circumference thereof, thereby inhibiting the conventionally seen local stretch at the side wall portion which makes the valve member to tend to get out of the engaging portion, and enabling to have the valve member operate normally.  
         [0068]     When the valve device  24  is placed in the open state, the ink chamber  16  is communicated with the space outside the recording apparatus  2 , via the air supply passage  13 , the clearance between the operating portion  67  and the through-hole  63   c , the communication passage  158  (shown in  FIGS. 5A-5C ) in the valve member  65 , the clearance between the guide bar  66  and an internal circumferential surface of the opening  74  in the engaging portion  73 , the air communication chamber  50 , a space between each adjacent two ribs  70  in the first portion  62   a  of the internal passage defined in the tubular member  62 , and the second portion  62   b  of the internal passage.  
         [0069]     Referring next to  FIG. 6 , there will be described how each valve device  23 ,  24  operates when the valve member  54 ,  65  is pushed upward by an amount larger than a normal, expected amount, in a case where the ink cartridge  1  is improperly attached or where a user tampers with the ink cartridge  1 , for instance.  
         [0070]     The biasing members  46 ,  63  respectively supporting the valve members  54 ,  65  are formed of elastic material. Hence, when the valve member  54 ,  65  is pushed upward, the side wall portion  36 ,  72  is stretched to be longer, thereby making the engaging portion  37 ,  73  inclined to widen the opening  37 ,  73  of the engaging portion  37 ,  73 . When the side wall portion  36 ,  72  is further stretched upward, the valve member  54 ,  65  makes the engaging portion  37 ,  73  greatly inclined to enlarge the opening  37   a ,  74  so that the valve member  54 ,  65  disengages from, or gets out of, the biasing member  46 ,  63  through the opening  37   a ,  74 . The valve member  54 ,  65  once having gotten out of the biasing member  46 ,  63  in this way can not return to the position to be held in close contact with the valve seat portion  46   a ,  63   a.    
         [0071]     In the ink cartridge according to the present embodiment, the lower end surfaces  71   a ,  70   a  of the ribs  71 ,  70  function as a limiter for inhibiting each of the valve members  54 ,  65  from moving by an excessively large amount. That is, the distance T 1 , T 2  between an upper surface of the engaging portion  37 ,  73  and the lower end surface  71   a ,  70   a  of the rib  71 ,  70  is determined such that before the opening  37   a ,  74  enlarges to a size larger than the valve member  54 ,  65  to allow the valve member  54 ,  65  to come out of the engaging portion  37 ,  73 , the upper surface of the engaging portion  37 ,  73  is brought into contact with the lower end surface  71   a ,  70   a  of the rib  71 ,  70 , as shown in  FIG. 6 .  
         [0072]     Hence, even when the valve member  54 ,  65  is pushed upward by an amount beyond a normal, expected amount, the valve member  54 ,  65  does not disengage from the biasing member  46 ,  63 , that is, does not get out of the biasing member  46 ,  63  through the opening  37   a ,  74 , thereby preventing the valve device  23 ,  24  from being left in their open state which may be otherwise caused and lead to problems such as leakage of the ink to the exterior of the ink cartridge, and increase in the viscosity of the ink due to evaporation of water or other components from the ink.  
         [0073]     According to the present ink cartridge, a limiter is constituted by a surface (namely, the lower end surface of each rib) with which the engaging portion is brought into contact before the valve member disengages from the engaging portion. That is, that surface can serve as a limiter by suitably determining the distance between the surface and the engaging portion, thereby enabling to simplify an internal structure of the ink cartridge.  
         [0074]     It is noted that the place where ink leakage occurs is not limited to the valve device  23  on the ink supply side. That is, it may happen that the ink is introduced into the first and second portions  62   a ,  62   b  of the internal passage, for instance when a user falls the ink cartridge while carrying the ink cartridge, and thereafter the ink leaks from the valve device  24  upon placing the valve device  24  on the air introduction side in the open state. Similarly, components of the ink such as water may evaporate at the valve device  23  on the ink supply side.  
         [0075]     When the valve member  54 ,  65  is pushed in an obliquely upward direction that is deviated from a normal, vertical direction in which the valve member  54 ,  65  is expected to move by being pushed, a part of the side wall portion  36 ,  72  is greatly stretched to accordingly deform the opening  37   a ,  74 , making the valve member  54 ,  65  prone to get out of the biasing member  46 ,  63  through the opening  37   a ,  74 . At the valve member  24  on the air introduction side, the guide bar  66  slides on the ribs  70  and is thus guided in a substantially vertical direction, as described above. Hence, it does not occur that only a part of the side wall portion  72  is greatly stretched, and thus the possibility of the disengagement of the valve member  65  from the biasing member  63  through the opening  74  is reduced. In this embodiment, since the air communication chamber has an internal passage communicating with the ink chamber, at a position to allow the valve member to enter the internal passage when the valve member is pushed upward, and a guiding portion constituted by the ribs extending from the inner surface of the internal passage toward the guide bar cooperates with the guide bar to constitute a guide device, a fluid passage is formed between the inner surface of the internal passage and the guide bar, and the guide bar can be properly guided along the ribs.  
         [0076]     In the present embodiment, this guiding of the valve member  65  to prevent local great stretch of the engaging portion  73  is implemented at the valve device  24  on the air introduction side, but a guide bar may be employed in the valve device  23  on the ink supply side, too, so as to have the valve member  54  guided by the ink inlet port  1   d  or the ribs  71 .  
         [0077]     According to this embodiment, even where the valve member  54 ,  65  disengages from the biasing member  46 ,  63  through the opening  37   a ,  74  when pushed abruptly since the biasing member  46 ,  63  has a dimension smaller than a nominal dimension because of a manufacturing error or for other reasons, or since the side wall portion  36 ,  72  does not sufficiently stretch accordingly to pushing of the valve member  54 ,  65 , it is prevented that the valve device  23 ,  24  of the ink cartridge is kept in the open state, for the following reason.  
         [0078]     That is, as described above, the diameter d 2 , d 4  of the protrusion  57   a ,  157   a  of the valve member  54 ,  65  is larger than the diameter d 1 , d 3  (shown in  FIG. 2 ) of the opening  37   a ,  74 , and the distance T 1 , T 2  (shown in  FIG. 2 ) is substantially equal to or slightly smaller than a height or thickness of the valve member  54 ,  65  in a direction parallel to the direction in which the valve member  54 ,  65  moves, i.e., a dimension from a lower end of the protrusion  57   a ,  157   a  to a lower surface of the engaging portion  37 ,  73  when not stretched. Hence, when the valve member  54 ,  65  disengages from the biasing member  46 ,  63  or gets out through the opening  37   a ,  74 , as shown in  FIG. 7 , the side wall portion  36 ,  72  contracts such that the engaging portion  37 ,  73  changes its shape along a lower surface of the valve member  54 ,  65  back to its original shape. Consequently, the valve member  54 ,  65  is sandwiched between the upper surface of the engaging portion  37 ,  73  and the lower end surface  71   a ,  70   a  of each rib  71 ,  70 , so that the lower surface of the valve member  54 ,  65  closes the opening  37   a ,  74 . Thus, in the event of the disengagement of the valve member  54 ,  65  from the biasing member  46 ,  63  through the opening  37   a ,  74 , the valve device  23 ,  24  is prevented from being left in the open state. In the conventional arrangement, on the other hand, the valve device  23 ,  24  can not be restored from this open state to a closed state where the valve member  54 ,  65  is placed in a second position to shut off the communication between the ink chamber and the exterior of the cartridge. Thus, according to the present embodiment, the problems due to the valve device  23 ,  24  left in the open state, such as ink leakage, are prevented.  
         [0079]     According to the first embodiment, a guiding portion of a guide device and a limiter are constituted by the same element, namely, the ribs. Hence, the number of components of the ink cartridge can be reduced.  
         [0080]     Referring next to  FIG. 8 , there will be described an ink cartridge according to a second embodiment of the invention. The parts and elements corresponding to those of the first embodiment are denoted by the same reference numerals and description thereof is omitted.  
         [0081]     In the first embodiment, the ribs  70 ,  71  limit the displacement of the valve member  65 ,  54 . However, according to the second embodiment, in place of the ribs  70  on the air introduction side and the ribs  71  on the ink supply side, engaging portions  73 ,  37  are brought into abutting contact with a ceiling surface  50   a  of the air communication chamber  50  and a ceiling surface  30   a  of the ink communication chamber  30 , respectively, to limit the displacement of the valve members  65 ,  54 , as shown in  FIG. 8 .  
         [0082]     As shown in  FIG. 8 , an inner surface of a first portion  62   a  of an internal passage is cylindrical and spaced from an outer circumferential surface of a guide bar  66  by a small distance, so that the guide bar  66  is guidable along the inner surface of the first portion  62   a  of the internal passage in sliding contact therewith.  
         [0083]     According to the second embodiment, since the air communication chamber has an internal passage communicating with the ink chamber, at a position to allow the valve member to enter in the internal passage when the valve member is pushed upward, the valve member, and a guiding portion constituted by the inner surface of the internal passage cooperates with the guide bar to constitute a guide device, an internal structure of the ink cartridge is simplified.  
         [0084]     According to the ink cartridge of the second embodiment, a limiter is constituted by a surface (namely, the ceiling surface of the air communication chamber and the ink communication chamber) with which the engaging portion is brought into contact before the valve member disengages from the engaging portion. That is, that surface can serve as a limiter by suitably determining the distance between the surface and the engaging portion, thereby enabling to simplify an internal structure of the ink cartridge.  
         [0085]     Referring to  FIG. 9 , there will be described an ink cartridge according to a third embodiment of the invention. The parts and elements corresponding to those in the first embodiment will be denoted by the same reference numerals and description thereof is omitted.  
         [0086]     As shown in  FIG. 9 , a plurality of ribs  76 , each having a downward protruding portion  76   a , extend from a ceiling surface of an ink communication chamber  30  to meet at a substantially central portion, in plan view, of the ink communication chamber  30 . The protruding portions  76   a  cooperate to constitute a protrusion whose lower end surface is directly opposed to the valve member  54  through an opening  37   a  formed in an engaging portion  37 , so that when the valve member  54  is lifted, the protrusion made up of the protruding portions of the ribs  76  enters the opening  37   a  of the engaging portion  37  to directly contact the valve member  54  so as to prevent an excessive displacement of the valve member  54 . It is noted that a horizontally extending part of the group of the ribs  76  corresponds to a bridge, and the protrusion made up of the protruding portions  76   a  of the ribs  76  corresponds to a direct contact portion.  
         [0087]     An upper end of a guide bar  66  of a valve member  65  is directly brought into contact with a ceiling surface of an air communication chamber  50 , so as to prevent an excessive movement of the valve member  65 . One of the ceiling surface  75  and the guide bar  66  has a communication passage  66   a  which allows air communication while the guide bar  66  is in contact with the ceiling surface  75 .  
         [0088]     According to the ink cartridge of the third embodiment, a limiter is constituted by a surface (namely, the ceiling surface  75 , and the lower end surface of the protrusion made up of the protruding portions  76   a  of the ribs  76 ) with which the valve member is directly brought into contact before the valve member disengages from the engaging portion. That is, that surface can serve as a limiter by suitably determining the distance between the surface and the engaging portion, thereby enabling to simplify an internal structure of the ink cartridge.  
         [0089]     In each of the above-described embodiments, the opening  37   a ,  74  are formed in the biasing members  46 ,  63  to open in the direction of the displacement of the valve members  54 ,  65  so as to permit communication of the ink and the air. However, a position at which the opening  37   a ,  74  is formed in the biasing member  46 ,  63  is not limited to this. For instance, as long as communication between the valve chamber accommodating the valve member  54 ,  65  and the ink or air communication chamber  30 ,  50  can be established, the opening  37   a ,  74  may be formed in the side wall portion  36 ,  72  of the biasing member  46 ,  63 . When the opening  37   a ,  74  is formed in the side wall portion  36 ,  72 , the communication passage  58 ,  158  of the valve member  54 ,  65  can be omitted.  
         [0090]     Each of the embodiments may be modified such that the air supply passage  13  in the mounting portion takes the same form as the ink inlet tube  12 , namely, a tubular form extending upward from the mounting portion, and the valve device  24  on the air introduction side has the same structure as the valve device  23  on the ink supply side. Alternately, each embodiment may be modified such that the ink supply tube  12  does not protrude from the mounting portion and the valve device  23  on the ink supply side has the same structure as the valve device  24  on the air introduction side.  
         [0091]     Although several embodiments of the present invention have been described above, it is to be understood that the invention is not limited to the details of the embodiments, but may be otherwise embodied with various changes and modifications which may occur to those skilled in the art without departing from the spirit and scope of the invention as defined in the appended claims.