Patent Publication Number: US-10308028-B2

Title: Waste ink storage mechanism and inkjet recording device including same

Description:
INCORPORATION BY REFERENCE 
     This application is based upon and claims the benefit of priority from the corresponding Japanese Patent Application No. 2017-109421 filed on Jun. 1, 2017, the entire contents of which are incorporated herein by reference. 
     BACKGROUND 
     The present disclosure relates to a waste ink storage mechanism which includes a waste ink tank for storing a waste ink exhausted from a recording head that discharges an ink to a recording medium such as a sheet and an inkjet recording device which includes such a waste ink storage mechanism. 
     As a recording device such as a facsimile, a copying machine or a printer, an inkjet recording device which discharges an ink so as to form an image is widely used because the inkjet recording device can form a high definition image. 
     In the inkjet recording device described above, for example, it is likely that the linearity of the ink is degraded (curved travel course) or the discharge thereof is prevented such that the printing performance of a recording head is lowered. As a cause of this problem, the occurrence of a meniscus abnormality can be considered, and the meniscus abnormality occurs because a foreign substance such as paper powder, dirt or dust produced when a sheet (recording medium) is transported, minute ink droplets (hereinafter referred to as a mist) discharged together with ink droplets for image recording or a mist scattered when the ink droplets are adhered to the recording medium is adhered to the ink discharge surface of a recording head. Moreover, as a cause of this problem, the lowering of sealing at the time of fitting of a cap as a result of a mist being adhered to a place where the cap is fitted so as to be dried and an increase in the viscosity of the ink within a nozzle resulting therefrom can also be considered. 
     Hence, a configuration is known in which in order to prevent the drying of the ink within a discharge nozzle where an opening is provided in the ink discharge surface of the recording head and the clogging of the nozzle resulting from an increase in the viscosity of the ink within the discharge nozzle, after the ink is forcefully pushed out (purged) from the nozzle, the purged ink adhered to the ink discharge surface (nozzle surface) is wiped away with a wiper and thus restoration processing on the recording head is performed. 
     A configuration is also known in which after a cleaning liquid is supplied to the ink discharge surface of the recording head, the ink discharge surface is wiped while the cleaning liquid is being held with the wiper and thus the restoration processing on the recording head is performed. 
     Since a waste ink is produced when the restoration processing described above is performed on the recording head, in the inkjet recording device, a waste ink tank for storing the waste ink is provided. When the waste ink tank is full, it is necessary to replace it with a new (empty) waste ink tank, and thus in the inkjet recording device, a detection sensor for detecting a liquid surface within the waste ink tank is provided. As the detection sensor, there are an electrode type, a float type and the like, and with consideration given to the exchangeability of the waste ink tank, the detection sensor is preferably installed outside the waste ink tank. 
     In the inkjet recording device described above, a configuration can be considered in which the detection sensor is arranged in a part of a waste ink tank fitting portion into which the waste ink tank is fitted on a downstream side (back side) in a direction of fitting of the waste ink tank, and in which in a side surface (back surface) of the waste ink tank on the downstream side in the direction of the fitting, an inflow port through which the waste ink flows in is provided. In this configuration, the waste ink tank is fitted into the waste ink tank fitting portion, and thus the downstream end of a waste ink passage path is coupled to the inflow port of the waste ink tank and the detection sensor is arranged close to the back surface of the waste ink tank. 
     SUMMARY 
     A waste ink storage mechanism according to a first aspect of the present disclosure includes a waste ink tank, a waste ink tank fitting portion and a capacitance sensor. The waste ink tank stores a waste ink exhausted from a recording head that discharges an ink on a recording medium. The waste ink tank is fitted to the waste ink tank fitting portion such that the waste ink tank can be fitted into and removed from the waste ink tank fitting portion. The capacitance sensor is provided in the waste ink tank fitting portion so as to detect that a liquid surface within the waste ink tank reaches a predetermined level. The waste ink tank includes: a first surface in which an inflow port through which the waste ink flows in is formed; and a second surface which is a side surface of the waste ink tank and which is different from the first surface. The capacitance sensor is arranged close to the second surface. 
     Further other objects of the present disclosure and specific advantages obtained by the present disclosure will become more apparent from the description of an embodiment given below. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a diagram showing the structure of an inkjet recording device which includes a waste ink storage mechanism according to an embodiment of the present disclosure; 
         FIG. 2  is a diagram when a first transport unit and a recording portion in the inkjet recording device shown in  FIG. 1  are seen from above; 
         FIG. 3  is a diagram of a recording head which forms line heads in the recording portion; 
         FIG. 4  is a diagram when the recording head is seen from the side of an ink discharge surface; 
         FIG. 5  is a diagram showing a configuration around the recording head, a sub-tank and a main tank; 
         FIG. 6  is a diagram showing the structure of the waste ink storage mechanism according to the embodiment of the present disclosure; 
         FIG. 7  is a diagram showing the appearance of the inkjet recording device shown in  FIG. 1 ; 
         FIG. 8  is a diagram showing a structure around a waste ink tank fitting portion in the waste ink storage mechanism according to the embodiment of the present disclosure; 
         FIG. 9  is a diagram showing the structure of a waste ink tank and a capacitance sensor in the waste ink storage mechanism according to the embodiment of the present disclosure; 
         FIG. 10  is a diagram showing the structure of the capacitance sensor in the waste ink storage mechanism according to the embodiment of the present disclosure; 
         FIG. 11  is a diagram showing the structure of the capacitance sensor in the waste ink storage mechanism according to the embodiment of the present disclosure; and 
         FIG. 12  is a diagram showing the structure of a waste ink storage mechanism according to a variation of the present disclosure. 
     
    
    
     DETAILED DESCRIPTION 
     An embodiment of the present disclosure will be described below with reference to drawings. 
     An inkjet recording device  100  according to the embodiment of the present disclosure will be described with reference to  FIGS. 1 to 11 . As shown in  FIG. 1 , in the inkjet recording device  100 , a paper feed cassette  2  which is a sheet storage portion is arranged in a lower portion within a device main body  1 . Within the paper feed cassette  2 , sheets P which are an example of a recording medium are stored. On the downstream side of the paper feed cassette  2  in a sheet transport direction, that is, above the right side of the paper feed cassette  2  in  FIG. 1 , a paper feed device  3  is arranged. The sheets P are separated and fed one by one with the paper feed device  3  upward to the right of the paper feed cassette  2  in  FIG. 1 . 
     The inkjet recording device  100  also includes a first sheet transport path  4   a  therewithin. With respect to the paper feed cassette  2 , the first sheet transport path  4   a  is located upward to the right in a paper feed direction. The sheet P fed out from the paper feed cassette  2  is transported with the first sheet transport path  4   a  upward along the side surface of the device main body  1 . 
     At the downstream end of the first sheet transport path  4   a  in the sheet transport direction, a registration roller pair  13  is provided. Furthermore, on the downstream side of the registration roller pair  13  in the sheet transport direction, a first transport unit  5  and a recording portion  9  are arranged. The sheet P fed out from the paper feed cassette  2  reaches the registration roller pair  13  through the first sheet transport path  4   a . The registration roller pair  13  feeds out the sheet P toward the first transport unit  5  while correcting the oblique feed of the sheet P and adjusting timing of an ink discharge operation performed by the recording portion  9 . 
     On the downstream side (the left side of  FIG. 1 ) of the first transport unit  5  in the sheet transport direction, a second transport unit  12  is arranged. The sheet P on which an ink image is recorded in the recording portion  9  is fed to the second transport unit  12 , and an ink discharged on the surface of the sheet P is dried while the sheet P is being passed through the second transport unit  12 . 
     On the downstream side of the second transport unit  12  in the sheet transport direction and in the vicinity of the left side surface of the device main body  1 , a decurler portion  14  is provided. The sheet P in which the ink is dried in the second transport unit  12  is fed to the decurler portion  14 , and a curl formed in the sheet P is corrected. 
     On the downstream side (upward of  FIG. 1 ) of the decurler portion  14  in the sheet transport direction, a second sheet transport path  4   b  is provided. When double-sided recording is not performed, the sheet P which is passed through the decurler portion  14  is ejected from the second sheet transport path  4   b  to a sheet ejection tray  15  provided outside the left side surface of the inkjet recording device  100 . 
     In an upper portion of the device main body  1  and above the recording portion  9  and the second transport unit  12 , a reverse transport path  16  for performing the double-sided recording is provided. When the double-sided recording is performed, the sheet P in which recording on a first surface is completed and which is then passed through the second transport unit  12  and the decurler portion  14  is fed through the second sheet transport path  4   b  to the reverse transport path  16 . Then, in the sheet P fed to the reverse transport path  16 , the transport direction is switched for the recording of a second surface, and the sheet P is fed though the upper portion of the device main body  1  toward the right side, is passed through the first sheet transport path  4   a  and the registration roller pair  13  and is fed again to the first transport unit  5  in a state where the second surface is faced upward. 
     Below the second transport unit  12 , a wipe unit  19  and a cap unit  90  are arranged. The wipe unit  19  is moved horizontally below the recording portion  9  when purge which will be described later is performed, wipes away the ink pushed out from the ink discharge ports of a recording head and collects the ink wiped away. The cap unit  90  is moved horizontally below the recording portion  9  when capping is performed on the ink discharge surface of the recording head, and is further moved upward so as to be fitted to the lower surface of the recording head. 
     As shown in  FIG. 2 , the recording portion  9  includes a head housing  10  and line heads  11 C,  11 M,  11 Y and  11 K held in the head housing  10 . These line heads  11 C to  11 K are supported at such a height that a predetermined distance (for example, 1 mm) is formed with respect to the transport surface of a first transport belt  8  in the first transport unit  5 , and are formed with one or more (here, one) recording heads  17  which are extended along a sheet width direction (the up/down direction of  FIG. 2 ) orthogonal to the sheet transport direction (the direction of an arrow X). 
     As shown in  FIGS. 3 and 4 , in the ink discharge surface F 1  of a head portion  18  of the recording head  17 , ink discharge regions R 1  where a large number of ink discharge ports  18   a  (see  FIG. 2 ) are aligned are provided. 
     The inks of four colors (cyan, magenta, yellow and black) which are stored in individual ink tanks (unillustrated) are supplied to the recording head  17  of the line heads  11 C to  11 K for the individual colors of the line heads  11 C to  11 K. 
     The recording head  17  discharges, according to image data received from an external computer by a control signal from a control portion  110  (see  FIG. 1 ), the inks from the ink discharge ports  18   a  toward the sheet P which is adsorbed and held to the transport surface of the first transport belt  8  and which is transported. In this way, in the sheet P on the first transport belt  8 , a color image in which the inks of the four colors of cyan, magenta, yellow and black are superimposed is formed. 
     In the recording head  17 , a cleaning liquid supply member  20  is provided which supplies a cleaning liquid. The cleaning liquid supply member  20  is arranged adjacent to the upstream side (the right side of  FIG. 3 ) of a wiper  25  in a wiping direction with respect to the head portion  18 . The cleaning liquid supply member  20  has a cleaning liquid supply surface F 2  which includes a cleaning liquid supply region R 2  where a large number of cleaning liquid supply ports for supplying the cleaning liquid are aligned. 
     As shown in  FIG. 5 , the downstream end of a cleaning liquid supply path  70  formed with a tube through which the cleaning liquid  23  is passed is connected to the cleaning liquid supply member  20 . The upstream end of the cleaning liquid supply path  70  is connected to one sub-tank  71  where the cleaning liquid  23  which is supplied to the cleaning liquid supply member  20  is stored. In the cleaning liquid supply path  70 , a supply pump  72  is provided which pumps up the cleaning liquid  23  from the sub-tank  71  so as to feed it to the cleaning liquid supply member  20 . In  FIG. 5 , for ease of understanding, the cleaning liquid  23  is hatched. 
     The downstream end of a cleaning liquid replenishment path  80  formed with a tube through which the cleaning liquid  23  is passed is connected to the sub-tank  71 . The upstream end of the cleaning liquid replenishment path  80  is connected to a main tank  81  where the cleaning liquid  23  which is replenished to the sub-tank  71  is stored. In the cleaning liquid replenishment path  80 , a replenishment pump  82  is provided which pumps up the cleaning liquid  23  from the main tank  81  so as to feed it to the sub-tank  71 . 
     In the sub-tank  71 , an atmospheric release port  71   a  is provided which is used to make the pressure of an internal space equal to the atmospheric pressure. In a predetermined position of the sub-tank  71 , a first detection sensor  73  is provided which detects the cleaning liquid  23 . When the lack of the liquid is detected by the first detection sensor  73 , until the liquid is detected, the cleaning liquid  23  is replenished by the replenishment pump  82  from the main tank  81  to the sub-tank  71 . In this way, the liquid surface (upper surface) of the cleaning liquid  23  within the sub-tank  71  is maintained at a substantially constant height within the sub-tank  71 . 
     In a lower portion of the main tank  81 , a second detection sensor  83  is provided which detects the cleaning liquid  23 . When the lack of the liquid is detected by the second detection sensor  83 , information that the main tank  81  is empty is notified to a display panel (unillustrated) of the inkjet recording device  100 . In this way, by a user or an operator, the main tank  81  is replaced with a new one or the cleaning liquid  23  is replenished to the main tank  81 . 
     In the inkjet recording device  100  described above, in order for the ink discharge surface F 1  of the recording head  17  to be cleaned, when printing is started after a stop for a long period of time or between printing operations, purge is performed in which the ink whose viscosity is increased is pushed out from the ink discharge ports  18   a  of the head portion  18 , and the cleaning liquid  23  is supplied from the cleaning liquid supply ports (unillustrated) of the cleaning liquid supply member  20 . Then, the cleaning liquid supply surface F 2  and the ink discharge surface F 1  are wiped with the wiper  25  of the wipe unit  19 . Here, the waste ink and the waste cleaning liquid wiped away with the wiper  25  are collected in a collection tray  27  provided in the wipe unit  19  and are stored in the waste ink tank  40  of a waste ink storage mechanism  30  which will be described later. This restoration operation on the recording head  17  is performed based on the control signal from the control portion  110  (see  FIG. 1 ) by control of the operations of the recording head  17 , the wipe unit  19 , the supply pump  72  and the like. 
     The waste ink storage mechanism  30  for storing the waste ink and the waste cleaning liquid will then be described. 
     As shown in  FIG. 6 , the waste ink storage mechanism  30  is formed with: the waste ink tank  40  in which the waste ink and the waste cleaning liquid are stored; a waste ink tank fitting portion  50  (see  FIG. 8 ) into which the waste ink tank  40  is fitted such that the waste ink tank  40  can be fitted into and removed from the waste ink tank fitting portion  50 ; a capacitance sensor  60  which detects that a liquid surface within the waste ink tank  40  reaches a predetermined level; and a waste ink tube  32  through which the waste ink and the waste cleaning liquid are passed and which is connected to the waste ink tank  40 . In  FIG. 6 , a waste liquid consisting of the waste ink and the waste cleaning liquid is hatched. 
     As shown in  FIGS. 7 and 8 , the waste ink tank fitting portion  50  is provided in a lower left portion of the device main body  1 , and the front thereof is covered by an opening/closing cover  1   a  which forms a portion of the exterior cover of the device main body  1 . 
     Inside the opening/closing cover  1   a , the waste ink tank fitting portion  50 , a main tank fitting portion  57  which is arranged adjacent to the waste ink tank fitting portion  50  and into which the main tank  81  for storing the cleaning liquid  23  is fitted and ink tank fitting portions  59   a  to  59   d  which are arranged above the waste ink tank fitting portion  50  and the main tank fitting portion  57  and into which the ink tanks (unillustrated) of the individual colors are fitted are provided. In the waste ink tank fitting portion  50 , a tank cover  55  is provided which is arranged on the upstream side (the front side, that is, the front side with respect to the plane of  FIG. 8 ) in a direction of fitting of the waste ink tank  40  and the main tank  81 . 
     As shown in  FIGS. 6 and 9 , the waste ink tank  40  is formed in an elongated shape extending in forward/backward directions (vertical directions with respect to the plane of  FIG. 7 , that is, the directions of arrows BB′), and includes a front surface (a side surface on the upstream side in the direction of the fitting (the direction of the arrow B))  41 , a back surface (a side surface on the downstream side in the direction of the fitting)  42 , a pair of side surfaces  43 , an upper surface  44  and a lower surface  45 . Within the waste ink tank  40 , a storage chamber S is formed in which the waste ink and the waste cleaning liquid are stored. 
     The capacitance sensor  60  is arranged close to the back surface (second surface)  42 . 
     In a part of the upper surface (first surface)  44  in the vicinity of the front surface  41 , an inflow port  44   a  is formed through which the waste ink and the waste cleaning liquid flow in. In other words, the inflow port  44   a  is formed at an end portion on a side opposite to the back surface  42  in the directions of fitting and removal of the waste ink tank  40  (the directions of the arrows BB′). In the vicinity of the inflow port  44   a  in the upper surface  44 , a cap placement portion  44   b  is formed which is used for placing a cap (unillustrated) covering the inflow port  44   a  when the waste ink tank  40  is replaced. 
     On the upper surface  44 , between the inflow port  44   a  and the back surface  42 , a step portion  44   c  is formed which projects upward from the inflow port  44   a  toward the back surface  42 . 
     In the center portion of the upper surface  44  in the forward/backward directions (the directions of the arrows BB′), a grasping portion  47  is provided. In the grasping portion  47 , a communication portion  47   a  is formed through which air can be passed and which makes the storage chamber S communicate in the forward/backward directions. 
     The capacitance sensor  60  is provided on the downstream side in the direction of fitting of the waste ink tank  40  in the waste ink tank fitting portion  50  (see  FIG. 8 ). As shown in  FIGS. 10 and 11 , the capacitance sensor  60  is formed with: a fixing portion  61  which is located and fixed to the frame  50   a  of the waste ink tank fitting portion  50 ; an electrode portion  62  which detects that the liquid surface (liquid amount) within the waste ink tank  40  reaches the predetermined level; a holding portion  63  which holds the electrode portion  62  and which slides in the forward/backward directions (the directions of the arrows BB′) with respect to the fixing portion  61 ; and a biasing member  64  which biases the holding portion  63  toward the back surface  42  of the waste ink tank  40 . 
     In the fixing portion  61 , a pair of guide portions  61   a  which are extended in the forward/backward directions (the directions of the arrows BB′), a boss  61   b  to which one end of the biasing member  64  is attached and a regulation portion  61   c  which regulates the movement of the holding portion  63  in the forward direction (the direction of the arrow B′) are formed. 
     In the side surfaces of the holding portion  63 , a pair of concave sliding portions  63   a  are formed which are extended in the forward/backward directions (the directions of the arrows BB′) and which slide with respect to the guide portions  61   a . In the holding portion  63 , a boss  63   b  to which the other end of the biasing member  64  is attached is formed in a part opposite the boss  61   b  of the fixing portion  61 . 
     In the front end portion (the left end portion of  FIG. 11 ) of the holding portion  63 , four engagement hooks  63   c  which engage with an edge portion of a detection surface  62   a  of the electrode portion  62  and a sandwich portion  63   d  which sandwich the electrode portion  62  together with the engagement hooks  63   c  so as to hold the electrode portion  62  and which can be elastically deformed are formed. In a state where the waste ink tank  40  is fitted into the waste ink tank fitting portion  50  (the state of  FIG. 6 ), the engagement hooks  63   c  of the holding portion  63  are pressed by the back surface  42  (see  FIG. 6 ) of the waste ink tank  40 . Hence, the distance from the detection surface  62   a  of the electrode portion  62  to the waste ink tank  40  is held constant. 
     The electrode portion  62  is formed such that its length in a width direction (a vertical direction with respect to the plane of  FIG. 6 ) is equal to or more than the length of the storage chamber S of the waste ink tank  40  in a width direction. The capacitance sensor  60  can detect, within a range of the height of the electrode portion  62 , that the liquid surface within the waste ink tank  40  reaches the predetermined level, and transmits the result of the detection to the control portion  110 . 
     As shown in  FIG. 6 , the waste ink tube  32  is arranged from a position of the waste ink tank fitting portion  50  (see  FIG. 8 ) on the downstream side (the right side of  FIG. 6 ) in the direction of the fitting to a position on the upstream side (the left side of  FIG. 6 ) in the direction of the fitting. Specifically, the exhaust port  27   a  of the collection tray  27  in the wipe unit  19  is arranged on the downstream side of the waste ink tank fitting portion  50  in the direction of the fitting. The upstream end  32   a  of the waste ink tube  32  is connected to the exhaust port  27   a , and the downstream end  32   b  thereof is drawn to the upstream side of the waste ink tank fitting portion  50  in the direction of the fitting and is inserted into (connected to) the inflow port  44   a  of the waste ink tank  40 . 
     As shown in  FIG. 8 , the tank cover  55  is formed so as to be able to turn about a turning shaft  55   a . In a state where the tank cover  55  is closed (the state of  FIG. 8 ), the tank cover  55  abuts on the front surface  41  of the waste ink tank  40  and the front surface of the main tank  81 , the waste ink tank  40  is arranged in a predetermined position of the waste ink tank fitting portion  50  and the main tank  81  is arranged in a predetermined position of the main tank fitting portion  57 . Then, as shown in  FIG. 6 , the holding portion  63  of the capacitance sensor  60  abuts on the back surface  42  of the waste ink tank  40 . 
     In the inkjet recording device  100 , when the liquid surface within the waste ink tank  40  reaches a predetermined position (for example, the position of  FIG. 6 ), information that the waste ink tank  40  is empty is notified to the display panel (unillustrated) of the inkjet recording device  100 . In this way, by the user or the operator, the waste ink tank  40  is replaced with a new one. 
     Specifically, by the user or the operator, the opening/closing cover  1   a  and the tank cover  55  (see  FIG. 8  for them) are opened, and the downstream end  32   b  of the waste ink tube  32  is pulled out (removed) from the inflow port  44   a  of the waste ink tank  40 . Then, the waste ink tank  40  is pulled out from the waste ink tank fitting portion  50 . 
     Thereafter, the new (empty) waste ink tank  40  is fitted into the waste ink tank fitting portion  50 , and the downstream end  32   b  of the waste ink tube  32  is inserted into the inflow port  44   a  of the waste ink tank  40 . Then, the tank cover  55  is closed so as to fit the waste ink tank  40  into the predetermined position of the waste ink tank fitting portion  50 , with the result that the capacitance sensor  60  abuts on the back surface  42  of the waste ink tank  40 . Thereafter, the opening/closing cover  1   a  is closed, and the replacement operation of the waste ink tank  40  is completed. 
     In the present embodiment, as described above, the waste ink tank  40  includes the upper surface  44  where the inflow port  44   a  through which the waste liquid (the waste ink and cleaning liquid) flows in is formed and the back surface  42 , and the capacitance sensor  60  is arranged close to the back surface  42 . In this way, it is possible to reduce the occurrence of a problem that the waste liquid flowing in through the inflow port  44   a  is passed along the back surface  42  to which the capacitance sensor  60  is arranged close and is made to flow down. Hence, it is possible to reduce the occurrence of a problem that when the waste liquid is not stored so as to reach the height of the capacitance sensor  60 , the capacitance sensor  60  erroneously detects the waste liquid. Consequently, with the capacitance sensor  60 , it is possible to highly accurately detect that the liquid surface within the waste ink tank  40  reaches the predetermined level. 
     As described above, the inflow port  44   a  is formed in the part on the side opposite to the back surface  42  of the upper surface  44  in the directions of the fitting and removal (the directions of the arrows BB′). In this way, the inflow port  44   a  can be arranged away from the back surface  42 , and thus it is possible to reduce the occurrence of the problem that the waste liquid flowing in through the inflow port  44   a  is passed along the back surface  42  and is made to flow down. 
     Since as described above, the upstream end  32   a  of the waste ink tube  32  (that is, the exhaust port  27   a  of the collection tray  27  connected to the waste ink tube  32 ) is arranged in the position of the waste ink tank fitting portion  50  on the downstream side in the direction of the fitting, even when the inflow port  44   a  is formed in the part of the waste ink tank  40  on the upstream side in the direction of the fitting, the waste ink tube  32  is used, and thus it is possible to easily guide the waste liquid exhausted from the recording head  17  to the inflow port  44   a  of the waste ink tank  40 . 
     The inflow port  44   a  is formed in the part of the upper surface  44  on the upstream side in the direction of the fitting, and thus when the waste ink tank  40  is replaced, the waste ink tube  32  is easily removed from the inflow port  44   a.    
     As described above, on the upper surface  44 , between the inflow port  44   a  and the back surface  42 , the step portion  44   c  is formed which projects upward from the inflow port  44   a  toward the back surface  42 . In this way, even when the waste liquid flowing in through the inflow port  44   a  is passed along the upper surface  44  and is made to flow in the direction of the back surface  42 , the waste liquid is prevented by the step portion  44   c  from flowing in the direction of the back surface  42 . In other words, with the step portion  44   c , it is possible to stop the flow of the waste liquid. Hence, it is possible to prevent the waste liquid from being passed along the back surface  42  and made to flow down. 
     As described above, the capacitance sensor  60  includes the holding portion  63  which holds the electrode portion  62  and which slides in the directions of the fitting and removal with respect to the fixing portion  61  and the biasing member  64  which biases the holding portion  63  toward the back surface  42 . In this way, in the state where the waste ink tank  40  is fitted into the waste ink tank fitting portion  50 , the distance between the electrode portion  62  and the waste ink tank  40  can be constantly held constant. Hence, it is possible to enhance the accuracy of detection of the capacitance sensor  60 . 
     As described above, in the state where the tank cover  55  is closed, the tank cover  55  abuts on the front surface  41  of the waste ink tank  40 , the waste ink tank  40  is arranged in the predetermined position of the waste ink tank fitting portion  50  and the capacitance sensor  60  abuts on the back surface  42 . In this way, after the replacement of the waste ink tank  40 , the tank cover  55  is closed, and thus the waste ink tank  40  can be reliably arranged in the predetermined position of the waste ink tank fitting portion  50 , and the capacitance sensor  60  can be reliably made to abut on the back surface  42 . 
     The embodiment disclosed here should be considered to be illustrative in all respects and not restrictive. The scope of the present disclosure is indicated not by the description of the above embodiment but by the scope of claims, and includes meanings equivalent to the scope of claims and all modifications within the scope. 
     For example, although in the embodiment discussed above, the example where the inflow port  44   a  is formed in the upper surface  44  is described, the present disclosure is not limited to this example. The inflow port  44   a  may be formed in the side surface  43 . In this case, the inflow port  44   a  is preferably formed in a part of the side surface  43  on the side opposite to the back surface  42 . 
     As in a waste ink storage mechanism  30  of a variation of the present disclosure shown in  FIG. 12 , the inflow port  44   a  may be formed in the front surface  41  (the side surface opposite to the back surface  42 ). In this case, as in the embodiment described above, the inflow port  44   a  can be arranged away from the back surface  42 , and thus it is possible to reduce the occurrence of the problem that the waste liquid flowing in through the inflow port  44   a  is passed along the back surface  42  and is made to flow down. Since the upstream end  32   a  of the waste ink tube  32  (that is, the exhaust port  27   a  of the collection tray  27  connected to the waste ink tube  32 ) is arranged in the position of the waste ink tank fitting portion  50  on the downstream side in the direction of the fitting, even when the inflow port  44   a  is formed in the part (the front surface  41 ) of the waste ink tank  40  on the upstream side in the direction of the fitting, the waste ink tube  32  is used, and thus it is possible to easily guide the waste liquid exhausted from the recording head  17  to the inflow port  44   a  of the waste ink tank  40 . 
     Although in the embodiment discussed above, the example where the cleaning liquid  23  is used so as to perform the restoration operation on the recording head  17  and where the waste ink and the waste cleaning liquid are stored in the waste ink tank  40  is described, the present disclosure is not limited to this example. Specifically, a configuration may be adopted where after the purge in which the ink is pushed out from the ink discharge ports  18   a  is performed, the ink discharge surface F 1  is wiped with the wiper  25  such that the restoration operation is performed on the recording head  17  and where only the waste ink is stored in the waste ink tank  40 .