Patent Publication Number: US-8523315-B2

Title: Recording device with a storage section including an absorption member to store a waste liquid collected from a recording head according to the operation of a pump which receives information from a processing unit which retains information about waste liquid retention and pump operation times

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a liquid container in which a liquid such as ink is stored, and an ink jet recording method of discharging ink droplets to record an image on a recording material, and more particularly, it relates to a liquid container to be detachably mounted on an ink jet recording device. 
     2. Description of the Related Art 
     Heretofore, a recording device which records an image on a recording material such as paper, cloth, a plastic sheet or a sheet for OHP has been proposed as a configuration on which various recording devices such as recording heads of a wire dot system, a thermal sensitive system, a thermal transfer system and an ink jet recording system can be mounted. 
     Among these systems, as a small-noise non-impact recording system, the ink jet recording system to discharge ink from a discharge port (a nozzle) arranged on a recording element and record the image on the recording material is incorporated in an ink jet recording device. The device can perform a high-density and high-speed recording operation. 
     The ink jet recording device employs a constitution corresponding to a function and a use configuration inherent in the system to which this recording device is applied. In general, the ink jet recording device includes a carriage on which an ink jet recording head is mounted, an ink tank as a liquid container which supplies ink to the recording head, a conveyance mechanism which conveys recording paper, and a control section which controls these components. 
     Moreover, the recording head which discharges ink droplets from a plurality of discharge ports is serially scanned in a direction (a main scanning direction) crossing a conveyance direction (a sub scanning direction) of recording paper. On the other hand, when the recording is not performed, the recording paper is intermittently conveyed (pitch conveyance) as much as an amount equal to a recording width. When the recording head including a large number of nozzles linearly arranged in parallel with the sub scanning direction to discharge ink is used and the recording head is scanned once on the recording paper, the recording is performed as much as a width corresponding to the number of the nozzles. 
     Moreover, since the ink jet recording device incurs a small running cost, the recording device can be miniaturized. Furthermore, the device can easily record a color image by use of a plurality of colors of ink. 
     For the above reasons, the ink jet recording device is used as an output unit of an information system, for example, a printer as an output terminal of a photocopier, a facsimile machine, an electronic typewriter, a word processor, a work station or the like. Alternatively, the ink jet recording device is used as a handy or portable printer disposed at a personal computer, an optical disk drive, a video device or the like. 
     On the other hand, as an energy generation element which allows the recording head to discharge the ink from the discharge ports, an electromechanical conversion member such as a piezo element is used. Alternatively, a liquid is heated by an electrothermal conversion element having a heating resistor member. 
     Above all, according to the recording head of the ink jet recording system in which the ink droplets are discharged using thermal energy, since the discharge ports are highly densely arranged, the image can be recorded with high resolution. Above all, when the electrothermal conversion element is used as the energy generation element in the recording head, the heat is easily miniaturized. Moreover, merits of the recording head can sufficiently be used in an IC technology and a micro processing technology which have remarkably advanced and have improved reliability thereof in a semiconductor field in recent years. The recording head using the electrothermal conversion element is advantageous because the head can highly densely be mounted easily, and manufactured with low cost. 
     The ink tank usually includes a storage bag in which the ink to be supplied to the recording head is stored, a joint portion to be connected to the ink jet recording device, and a housing in which these components are incorporated. In the ink jet recording device, preliminary discharge is performed in order to prevent an initial discharge defect after the recording head is left to stand for a short time period. Also in the device, an ink sucking operation from the recording head left to stand for a long time period is periodically performed in order to prevent non-discharge due to mixed bubbles after the recording head is left to stand for the long time period. 
     Waste ink generated by the preliminary discharge and the periodic ink suction from the recording head is discharged into the ink jet recording device. In order to miniaturize the whole ink jet recording device, the conventional ink tank includes a waste ink absorption member in which the waste ink generated by the preliminary discharge and the periodic ink suction is collected and stored. This waste ink absorption member is incorporated in the housing. 
     That is, the waste ink which has originally been discharged into the ink jet recording device is absorbed by the waste ink absorption member, and the member is arranged in the ink tank. According to such a constitution, the ink jet recording device can be miniaturized. Furthermore, the ink tank is replaced with a new ink tank at a time when the ink to be supplied to the recording head is consumed. That is, when the ink tank is replaced, the waste ink absorption member disposed in the ink tank is replaced with a new member. Therefore, even in a case where it is constituted that the waste ink absorption member is incorporated in the ink tank, the ink tank is inhibited from being excessively enlarged. 
     As the constitution in which the waste ink absorption member is incorporated in the ink tank to miniaturize the recording device, a constitution is disclosed in which the waste ink absorption member is incorporated in the ink tank and further the recording device includes a unit to distribute the waste ink to a plurality of ink tanks (see Japanese Patent Application Laid-Open No. 2003-127433). In this constitution, since the waste ink is distributed to the plurality of ink tanks by the recording device, the whole recording device can be miniaturized. 
     In this type of ink jet recording device, when the waste ink is collected in the ink tank, the waste ink needs to be securely absorbed by the waste ink absorption member disposed in the ink tank. In a case where the waste ink is not absorbed or stored in the waste ink absorption member to cause existence of floating ink, the ink might leak from the ink tank. To prevent such ink leakage, in the conventional ink tank, a joint portion for the waste ink via which the waste ink is introduced into the ink tank needs to be hermetically closed with a rubber seal or the like. This structure is one cause for increase of the manufacturing cost of the ink tank. 
     SUMMARY OF THE INVENTION 
     To solve the problem, an object of the present invention is to provide a liquid container and a recording device so that waste liquid can securely be collected by an absorption member disposed in the waste liquid to prevent drop of reliability due to liquid leakage with a comparatively simple and inexpensively manufactured constitution. 
     To achieve the above object, a constitution of the present invention is a recording device on which a storage section including an absorption member to store a waste liquid collected from the recording head, and an information holding portion which retains information, the recording device comprising:
         a pump which feeds the waste liquid collected from the recording head to the second storage section; and   a control unit which controls the pump,   wherein the control unit controls an operation of the pump based on the information retained by the information holding portion, the information including information on the total amount of the waste liquid absorbed by the absorption member, and information on the previous operation time of the pump.       

     According to the present invention, when the waste liquid is discharged into the liquid container, liquid leakage from the liquid container can be prevented from being caused by existence of a floating liquid generated in a case where the waste liquid is not securely collected by a waste liquid absorption member disposed in the liquid container. 
     Moreover, according to the present invention, by a comparatively simple method with a small manufacturing cost, the waste liquid can securely be collected by the waste liquid absorption member disposed in the liquid container to prevent drop of reliability due to the liquid leakage. 
     Further features of the present invention will become apparent from the following description of exemplary embodiments with reference to the attached drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view showing an ink tank according to an embodiment. 
         FIG. 2  is a side view showing the ink tank. 
         FIG. 3  is a perspective view showing an ink supply system on the side of an ink jet recording device to which the ink tank of the present embodiment is applied. 
         FIG. 4  is a circuit diagram of the ink jet recording device and the ink tank. 
         FIG. 5  is a flow chart showing an operation of discharging waste ink. 
         FIG. 6  is a perspective view showing an ink tank according to another embodiment. 
         FIG. 7  is a flow chart showing an operation of discharging waste ink according to the other embodiment. 
     
    
    
     DESCRIPTION OF THE EMBODIMENTS 
     Embodiments of a liquid container, a recording device and a liquid collection system according to the present invention will hereinafter be described with reference to the drawings. 
     An ink tank of the present embodiment is a so-called main ink tank. In the tank, ink as a liquid to be supplied to a sub ink tank is stored. The sub ink tank is to be moved integrally with a recording head which discharges a liquid in the recording device. The ink is supplied from the ink tank to the recording head via this sub ink tank. 
       FIG. 1  is a perspective view showing the ink tank which is an embodiment of the liquid container. As shown in  FIG. 1 , an ink tank  5  of the embodiment includes a first storage section  11  in which the ink to be supplied to an ink jet recording head is stored, and a second storage section  12  in which waste ink as a waste liquid collected from the ink jet recording head is stored. The ink tank  5  also includes an information holding portion  13  which can retain information concerned with the waste ink to be collected from the ink jet recording head. 
     The first storage section  11  has a plurality of storage chambers in which a plurality of colors of ink to be supplied to the recording head are stored independently of one another. The first storage section  11  is provided with a plurality of joint portions  18  for ink supply which are connected to an ink supply system on the side of the ink jet recording device. From the joint portions, the plurality of colors of ink are supplied to the recording head. As one example, the ink tank  5  of the present embodiment includes the joint portions  18  for supplying the ink of four colors of yellow (Y), magenta (M), cyan (C) and black (K). 
     Moreover, in the ink jet recording head on which the ink tank  5  is mounted, after the ink jet recording head is left to stand for a short time, the ink is preliminarily discharged in order to prevent an initial discharge defect. In this ink jet recording device, when the ink jet recording head is left to stand for a long time, the ink is periodically sucked. This is performed in order to prevent that the ink jet recording head does not discharge any ink owing to bubbles mixed in the ink jet recording head which has been left to stand for the long time. 
     To perform this operation, the second storage section  12  includes a waste ink absorption member  16  in which the waste ink generated by the preliminary discharge and the periodic ink suction is collected from the recording head and stored. The waste ink does not contribute to image formation. The second storage section  12  also includes a joint portion  19  for ink collection into which the waste ink collected from the ink jet recording head is introduced. 
     Moreover, the information holding portion  13  of the ink tank  5  includes an information recording medium  17  in which information can be recorded. In this information recording medium  17 , information on a total amount of waste ink absorption is recorded as a total amount of the waste ink absorbed by the waste ink absorption member  16 . As this total waste ink absorption, an initial value of “0” is recorded, when the ink tank is a new tank. In the information recording medium  17 , a waste ink collection time (a collection period) of one past time close to the present time, that is, the previous time is recorded. Any waste ink collection time is not recorded, when the ink tank  5  is the new tank. 
     Furthermore, in the information recording medium  17 , information on the shortest time period from a time when the collection of the waste ink into the ink tank  5  is completed until the next waste ink collection can be performed is stored. 
     The next waste ink collection cannot be performed until the waste ink fed to the second storage section  12  by the previous waste ink collection is sufficiently absorbed by the waste ink absorption member  16 . If the next waste ink collection is performed with the non-absorbed waste ink left in the waste ink absorption member  16 , the waste ink cannot be absorbed by the waste ink absorption member  16 , and leaks from the second storage section  12 . 
     The shortest time period X of the waste ink absorption is a waiting time required until the amount of the waste ink which is not absorbed by the waste ink absorption member  16  from the previous waste ink collection decreases to a predetermined amount or less and newly collected waste ink can sufficiently be absorbed by the waste ink absorption member  16 . 
     It is to be noted that the shortest time period X of the waste ink absorption is a value which changes with the total amount of the waste ink absorption. When the total amount of the waste ink absorption increases, the shortest time period X of the waste ink absorption gradually increases. 
     That is, information to be recorded in the information recording medium  17  includes the total amount of the waste ink absorption by the waste ink absorption member  16  including an initial value of zero, the shortest time period X of the waste ink absorption having a value which continuously changes with the total amount of the waste ink absorption, and the previous collection time of the waste ink. 
     
       
         
           
               
               
               
             
               
                 TABLE 1 
               
             
            
               
                   
               
               
                 Total amount (CC) 
                 Shortest time period X of waste 
                   
               
               
                 of waste ink 
                 ink absorption (second) 
               
            
           
           
               
               
               
            
               
                 absorption 
                 First ink 3A 
                 Second ink 3B 
               
               
                   
               
               
                 0 to 1 
                 50 
                 120 
               
               
                 2 to 3 
                 50 
                 120 
               
               
                 3 to 4 
                 50 
                 125 
               
               
                 4 to 5 
                 55 
                 130 
               
               
                 5 to 6 
                 60 
                 150 
               
               
                   
               
            
           
         
       
     
     Table 1 shows one example of the shortest time period X of the waste ink absorption. The shortest time period X of the waste ink absorption differs with a type of the ink. When the ink is permeable ink (hereinafter referred to as the first ink) such as color ink including a surface active agent, a value of the period is comparatively small. When the ink is impermeable ink (hereinafter referred to as the second ink) such as black pigment ink, the value of the period comparatively increases. Table 1 shows first ink  3 A and second ink  3 B as typified ink. 
     Moreover, in actual, the waiting time from the previous waste ink absorption until the next waste ink absorption can be performed also changes with the amount of the previously collected waste ink. The amount of the waste ink to be collected differs between the preliminary discharge and restorative suction. Each of the preliminary discharge and the restorative suction has a plurality of modes, and the amount of the waste ink to be collected differs with the mode. Therefore, as shown in Table 1, the shortest time period X of the absorption extracted from the table for use in a case where a standard amount of the waste ink is collected is sometimes corrected in accordance with an actual amount of the waste ink absorption. 
     Furthermore, as the total amount of the waste ink absorption by the waste ink absorption member  16  increases, an ink absorption capability of the waste ink absorption member  16  gradually deteriorates. Therefore, the amount of the waste ink absorption per unit time gradually decreases. Table 1 shows one example in which the shortest time period X of the waste ink absorption changes with the total amount of the waste ink absorption, in a case where it is assumed that the waste ink can sufficiently be absorbed by the waste ink absorption member  16  within this period and any floating ink does not exist. It is to be noted that this value of the shortest time period X of the waste ink absorption is determined by the type of the ink as described above. In addition, the value is determined by a structure of the ink tank, and a material and a shape of the waste ink absorption member  16 . 
       FIG. 3  is a perspective view showing an ink supply system on the side of the ink jet recording device. As shown in  FIG. 3 , the ink supply system in which the above ink tank (the main tank)  5  of the embodiment is used includes an ink jet recording head  6  which discharges ink droplets to form an image, characters and the like on a recording material. This ink supply system includes a sub ink tank  7 , and a tank attaching portion (not shown) to which the ink tank  5  is detachably attached. The sub ink tank has a function of supplying the ink supplied from the ink tank  5  to the ink jet recording head  6  to maintain an appropriate negative pressure. 
     As one example, the inside of the sub ink tank  7  is divided into ink chambers of four colors of yellow (Y), magenta (M), cyan (C) and black (K). The ink jet recording head  6  is constituted integrally with the sub ink tank  7 . When the recording material is scanned and the ink jet recording head  6  discharges a plurality of colors of ink droplets, an image is formed on the recording material. 
     The ink tank  5  of the present embodiment is connected to the sub ink tank  7  via ink supply tubes  21 , and the ink is supplied from the ink tank  5  to the sub ink tank  7  via the ink supply tubes  21 . Instead of the ink supply tubes  21 , a joint mechanism (not shown) via which the sub ink tank  7  is disconnectably connected to the ink tank  5  may be provided, and the present invention is applicable to such a constitution. 
     The ink jet recording head  6  causes an initial discharge defect even after the head is left to stand for a comparatively short period. Therefore, when the head is left to stand even for a short period, the preliminary discharge is performed in order to prevent the initial discharge defect before the image is recorded in the recording material. Moreover, bubbles are sometimes mixed in the ink jet recording head  6  after the head is left to stand for a long period. In this case, an operation of sucking the bubbles from the ink jet recording head  6  is performed. Furthermore, the ink is sucked. This ink sucking operation is usually performed periodically after the ink jet recording head  6  is left to stand for the long period. 
     As shown in  FIG. 3 , a suction cap  23  which abuts on the ink jet recording head  6  on a discharge port side is connected to a suction pump  24  and the ink tank  5  via a waste ink discharge tube  22 . To perform the above preliminary discharge in order to prevent the initial discharge defect, after the ink jet recording head  6  is moved to and fixed at such a position as to face the suction cap  23 , the ink jet recording head  6  discharges the plurality of ink droplets into the suction cap  23 . Subsequently, when the suction pump  24  is operated, the waste ink discharged into the suction cap  23  by the preliminary discharge is circulated through the ink tank  5  via the waste ink discharge tube  22 , sucked by the waste ink absorption member  16  and stored in the ink tank  5 . The amount of the waste ink to be discharged into the suction cap  23  by the preliminary discharge sometimes differs with the mode of the preliminary discharge. The amount of the waste ink to be discharged into the suction cap  23  by the preliminary discharge is smaller than the amount of the waste ink to be generated by the restorative suction described later. Therefore, the suction pump  24  is operated, when the preliminary discharge is performed several times. 
     Moreover, in the ink sucking operation of removing the bubbles after the ink jet recording head  6  is left to stand for the long period as described above, the ink jet recording head  6  is moved to and fixed at such a position as to face the suction cap  23 . Subsequently, after the suction cap  23  is brought into close contact with the ink jet recording head  6  on the discharge port side, the suction pump  24  is operated, thereby performing the ink sucking operation. The waste ink generated by this restorative suction operation is circulated through the ink tank  5  via the waste ink discharge tube  22 , absorbed by the waste ink absorption member  16  and stored in the ink tank  5 . The amount of the waste ink to be generated by the restorative suction operation sometimes differs with the mode of the restorative suction. 
       FIG. 4  is a circuit diagram of the ink jet recording device. 
     An ink jet recording device main body  300  includes a CPU  310 , an ROM  311  in which a control program and data are stored and an RAM  312  in which data of control, image processing and the like is temporarily stored and from which the data is read. 
     When the ink tank  5  is mounted on the recording device  300 , the information holding portion  13  is connected to the CPU  310  via an electric contact, so that the information can be recorded in the information recording medium  17  of the information holding portion  13  and can be read from the information recording medium  17 . 
     Alternatively, the information holding portion  13  and the CPU  310  may exchange the information by radio. 
       FIG. 5  is a flow chart showing an operation of discharging the waste ink according to the present embodiment. As shown in step  101  of  FIG. 5 , the ink tank  5  is mounted on a tank mounting portion of the ink jet recording device. When the ink tank  5  is mounted, as shown in step  102 , the total amount of the waste ink absorption is read by a control section (not shown) of the ink jet recording device from the information recorded in the information recording medium  17  of the information holding portion  13  disposed at the ink tank  5 . It is to be noted that this total amount of the waste ink absorption has an initial value of “zero”, when the ink tank  5  is a new tank. This value is read by the control section of the ink jet recording device. 
     Moreover, when the waste ink is continuously discharged to the waste ink absorption member  16 , the shortest time period X of the waste ink absorption corresponding to the total amount of the waste ink absorption is read from the information recording medium  17  of the ink tank  5  by the control section of the ink jet recording device. This shortest time period X of the waste ink absorption is the shortest time period when the waste ink can sufficiently be absorbed by the waste ink absorption member  16  and any floating ink does not exist in the second storage section  12  of the ink tank  5 . The previous collection time of the waste ink is read from the information recording medium  17  by the control section of the ink jet recording device. However, the time is not read, when the ink tank  5  is the new tank. 
     Subsequently, when the suction pump  24  needs to be operated, as shown in step  103 , a command for operating the suction pump  24  is generated in the ink jet recording device. When the command for operating the suction pump  24  is generated, first as shown in step  104 , a lapse time Y from the previous collection time of the waste ink up to now is calculated. Subsequently, as shown in step  105 , this lapse time Y from the previous collection time of the waste ink is compared with a value of the shortest time period X of the waste ink absorption. 
     When Y≧X, a sufficient time elapses from the previous time when the waste ink is discharged into the ink tank  5  and absorbed by the waste ink absorption member  16 . Therefore, in a case where the waste ink is absorbed by the waste ink absorption member  16 , any floating ink does not exist in the ink tank  5  and the waste ink is newly discharged into the tank, it is judged that the waste ink can be absorbed by the waste ink absorption member  16 . The step advances to step  106  to operate the suction pump  24 . In consequence, the waste ink is discharged into the second storage section  12  of the ink tank  5 , and absorbed by the waste ink absorption member  16 . 
     When Y&lt;X, as shown in step  107 , the suction pump is stopped for a predetermined time period, and waits until Y≧X is satisfied. Subsequently, when Y≧X is satisfied, the suction pump  24  operates. During this stop, a sufficient time elapses from the previous time when the waste ink is discharged into the ink tank  5  and absorbed by the waste ink absorption member  16 . Therefore, the existence of the floating ink in the second storage section  12  of the ink tank  5  is eliminated. Therefore, even when the waste ink is newly discharged to the second storage section  12 , the waste ink can satisfactorily be absorbed by the waste ink absorption member  16 . The ink leakage due to overflow of the waste ink can be prevented. Finally, after the operation of the suction pump  24  ends, as shown in step  108 , the total amount of the waste ink absorption and the collection time of the waste ink are recorded in the information recording medium  17  of the ink tank  5 , respectively. In consequence, a series of operations of discharging the waste ink are completed. 
     The total amount of the waste ink absorption is obtained by adding the amount of the ink presently fed by the suction pump  24  to the total amount of the waste ink absorption read from the information recording medium  17  in the step  102  before operating the suction pump  24 . The amount of the waste ink to be generated by the restorative suction and the preliminary discharge differs with the mode. In the ROM  311  or the RAM  312 , information on the amount of the waste ink to be generated by each mode of restorative suction and each mode of preliminary discharge is stored. The amount of the ink fed into the second storage section  12  by the suction pump  24  is calculated based on the information. The calculation result is added to the total amount of the waste ink absorption read from the information recording medium  17 . When the preliminary discharge is performed a plurality of times, the waste ink is collected from the cap  23  in some case. In this case, the amount of the waste ink preliminarily discharged the plurality of times is added. This value is newly stored in the information recording medium  17 . 
     A value obtained by further subtracting the amount of the ink evaporated from the second storage section  12  may be stored according to the lapse time from the previous collection time of the waste ink. 
     As the collection time of the waste ink, a pump operating time such as a time when the operation of the suction pump  24  is started or stopped is used. 
     As described above, according to the ink tank  5  of the embodiment including the information holding portion  13 , it can be prevented that the waste ink is discharged into the second storage section  12  in a case where the floating ink which is not absorbed by the waste ink absorption member  16  of the second storage section  12  exists. Therefore, according to this ink tank  5 , when the waste ink is discharged into the second storage section  12 , the ink leakage from the ink tank  5  can be prevented. 
     Furthermore, according to this ink tank  5 , the joint portion  19  for ink collection does not have to employ a special sealed structure. Therefore, with a comparatively simple constitution and low manufacturing cost, the first ink is securely collected by the waste ink absorption member  16 , and drop of reliability due to the ink leakage can be prevented. 
     (Another Embodiment) 
     An ink tank according to another embodiment will be described with reference to the drawings. The tank includes a light emitting portion which emits light to indicate that the waste ink collecting operation is stopped for the predetermined time period. Since the present embodiment has substantially the same constitution as that of the ink tank  5  of the above embodiment, the same members are denoted with the same reference numerals for description. 
       FIG. 6  is a perspective view showing the ink tank according to the other embodiment. As shown in  FIG. 6 , a first storage section  11  of an ink tank  15  of the present embodiment includes joint portions  18  of four colors of yellow (Y), magenta (M), cyan (C) and black (K) in the same manner as in the constitution shown in  FIG. 1 . 
     Moreover, the second storage section  12  of the ink tank  15  includes a waste ink absorption member  16  in which waste ink is collected and stored in the same manner as in the constitution shown in  FIG. 1 . The ink tank  15  includes a light emitting portion  26  to emit visible light which can visually be recognized by a user, and an information holding portion  13  having an information recording medium  17  in which the information can be recorded. The light emitting portion  26  of the present embodiment contains a control circuit which controls a light emission state. 
     As shown in  FIG. 6 , in the same manner as in the above embodiment, a total amount of waste ink absorption is recorded in the information recording medium  17 . When the ink tank  15  is a new tank, an initial value of “zero” is recorded as this total amount of the waste ink absorption. In the information recording medium  17 , a collection time of the waste ink of one past time close to the present time, that is, the previous time is stored. When the ink tank  15  is the new tank, the collection time of the waste ink is not recorded. Furthermore, the shortest time period X of the waste ink absorption is also recorded. The period is the shortest time period when the waste ink can sufficiently be absorbed by the waste ink absorption member  16  and any floating ink does not exist, in a case where the waste ink is discharged to the waste ink absorption member  16 . A value of the period changes with the total amount of the waste ink absorption. 
       FIG. 7  is a flow chart showing an operation of discharging the waste ink according to the ink tank of the other embodiment. As shown in step  101  of  FIG. 7 , the ink tank  15  is mounted on a tank mounting portion of the ink jet recording device. When the ink tank  15  is mounted, as shown in step  102 , the total amount of the waste ink absorption is read by a control section of the ink jet recording device from the information recording medium  17  of the information holding portion  13  disposed at the ink tank  15  in the same manner as described above. It is to be noted that this total amount of the waste ink absorption has an initial value of “zero”, when the ink tank  15  is a new tank. This value is read by the control section of the ink jet recording device. 
     Moreover, when the waste ink is continuously discharged to the waste ink absorption member  16 , the shortest time period X of the waste ink absorption corresponding to the total amount of the waste ink absorption is read from the information recording medium  17  of the ink tank  15  by the control section of the ink jet recording device. This shortest time period X of the waste ink absorption is the shortest time period when the waste ink can sufficiently be absorbed by the waste ink absorption member  16  and any floating ink does not exist in the second storage section  12  of the ink tank  15 . The previous collection time of the waste ink is read from the information recording medium  17  by the control section of the ink jet recording device. However, the time is not read, when the ink tank  15  is the new tank. 
     Subsequently, when the suction pump  24  needs to be operated, as shown in step  103 , a command for operating the suction pump  24  is generated in the ink jet recording device in the same manner as described above. When the command is generated, first as shown in step  104 , a lapse time Y from the previous collection time of the waste ink up to now is calculated. Subsequently, as shown in step  105 , this lapse time Y from the previous collection time of the waste ink is compared with a value of the shortest time period X of the waste ink absorption. 
     When Y≧X, a sufficient time elapses from the previous time when the waste ink is discharged into the ink tank  15  and absorbed by the waste ink absorption member  16 . Therefore, in a case where the waste ink is absorbed by the waste ink absorption member  16 , any floating ink does not exist in the ink tank  15  and the waste ink is newly discharged into the tank, it is judged that the waste ink can be absorbed by the waste ink absorption member  16 . The step advances to step  106  to operate the suction pump  24 . In consequence, the waste ink is discharged into the waste ink absorption member  16  of the second storage section  12  of the ink tank  5 . 
     When Y&lt;X, as shown in step  109 , the suction pump is stopped for a predetermined time period, and waits until Y≧X is satisfied. Subsequently, the suction pump  24  operates. To allow a user to recognize that the pump is stopped for the predetermined time period, the light emitting portion  26  of the ink tank  15  emits light. When an emitted state of the light emitting portion  26  is visually recognized by the user, the user is informed that the pump is stopped. In the same manner as described above, during this stop, a sufficient time elapses from the previous time when the waste ink is discharged into the ink tank  15  and absorbed by the waste ink absorption member  16 . Therefore, the existence of the floating ink in the second storage section  12  of the ink tank  15  is eliminated. Therefore, even when the waste ink is newly discharged to the second storage section  12 , the waste ink can satisfactorily be absorbed by the waste ink absorption member  16 . The ink leakage due to overflow of the waste ink can be prevented. Finally, after the operation of the suction pump  24  ends, as shown in step  108 , the total amount of the waste ink absorption and the collection time of the waste ink are recorded in the information recording medium  17  of the ink tank  15 . In consequence, a series of operations of discharging the waste ink are completed. 
     According to the ink tank  15  of the present embodiment, since the ink tank includes the light emitting portion  26 , the user can visually easily confirm that an ink sucking operation is stopped for the predetermined time period. It is to be noted that, in addition to the light emitting portion  26 , the ink tank of the embodiment may include an alarming portion (not shown) which emits warning sound, if necessary, so that the user can confirm that the ink sucking operation is stopped fro the predetermined time period owing to the warning sound. 
     While the present invention has been described with reference to exemplary embodiments, it is to be understood that the invention is not limited to the disclosed exemplary embodiments. The scope of the following claims is to be accorded the broadest interpretation so as to encompass all such modifications and equivalent structures and functions. 
     This application claims the benefit of Japanese Patent Application No. 2006-244148, filed Sep. 8, 2006, which is hereby incorporated by reference herein in its entirety.