Patent Publication Number: US-11660873-B2

Title: Liquid ejection apparatus

Description:
BACKGROUND OF THE DISCLOSURE 
     Field of the Disclosure 
     The present disclosure relates to a liquid ejection apparatus that is widely applicable, for example, as an inkjet printing apparatus including a print head capable of ejecting ink in an inkjet system. 
     Description of the Related Art 
     In Japanese Patent Laid-Open No. 2019-025818, there is disclosed a technique in which a member including a float having a specific gravity smaller than that of ink is included in a revolvable manner inside a chamber for storing ink, and pivotal movement of this member is detected by a sensor, so that the remaining amount of the ink inside the chamber is detected. Specifically, in the technique disclosed in Japanese Patent Laid-Open No. 2019-025818, a detected part of the pivot member is detected by the sensor, so that whether or not the liquid surface of the ink inside the chamber is equal to or higher than a predetermined height is detected. 
     SUMMARY OF THE DISCLOSURE 
     A liquid ejection apparatus is provided with a liquid ejection head configured to eject supplied liquid, a storage unit configured to store the liquid to be supplied to the liquid ejection head, a pivot member configured to be immersed in the liquid stored in the storage unit and be revolvable according to an amount of the liquid, and a detection unit configured to detect the amount of the liquid by use of the pivot member, and the liquid ejection apparatus includes a pivot unit configured to force the pivot member to pivotally move. 
     Further features of the present disclosure will become apparent from the following description of exemplary embodiments with reference to the attached drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG.  1 A  and  FIG.  1 B  are diagrams for explaining an overview of a configuration of a printing apparatus, which is an example of a liquid ejection apparatus according to an embodiment; 
         FIG.  2 A  and  FIG.  2 B  are diagrams illustrating the movement of a pivot member in a case where ink is supplied to an ink chamber; 
         FIG.  3 A  and  FIG.  3 B  are diagrams illustrating the movement of the pivot member in a case where the amount of ink stored in the ink chamber is reduced; 
         FIG.  4 A  and  FIG.  4 B  are diagrams for explaining forced pivotal movement in the printing apparatus according to the first embodiment; and 
         FIG.  5 A  and  FIG.  5 B  are diagrams for explaining forced pivotal movement in the printing apparatus according to the second embodiment. 
     
    
    
     DESCRIPTION OF THE EMBODIMENTS 
     However, in the technique disclosed in Japanese Patent Laid-Open No. 2019-025818, a pivotal shaft of the pivot member is disposed in the vicinity of the bottom section of the chamber. Therefore, shortly before the ink inside the chamber runs out, the liquid surface of the ink is located on the pivotal shaft. Therefore, if the ink inside the chamber is let stand for a long period of time in a state shortly before running out, there is a possibility that the ink around the pivotal shaft becomes thickened or solidified, which makes it difficult for the pivot member to make a pivotal movement, so that the function of detecting the ink remaining amount is deteriorated. 
     The present disclosure has been made in view of the above-described problem, so as to provide a technique capable of preventing deterioration in the function of detecting the remaining amount of ink even though the ink is thickened or solidified. 
     Hereinafter, with reference to the accompanying drawings, a detailed explanation will be given of an example of a liquid ejection apparatus according to the present disclosure. Note that it is not intended that the following embodiments limit the present disclosure, and every combination of the characteristics explained in the embodiments is not necessarily essential to the solution in the present disclosure. In addition, unless otherwise specified, the relative positions, shapes, etc., of the constituent elements described in the present embodiments are merely examples and are not intended to limit the range of the present disclosure as such. 
     First Embodiment 
     First, with reference to  FIG.  1 A  through  FIG.  4 B , an explanation will be given of the liquid ejection apparatus according to the first embodiment. Note that, in the specification of the present application, a printing apparatus that ejects ink onto a print medium for printing is taken as an example of the liquid ejection apparatus for the sake of explanation.  FIG.  1 A  and  FIG.  1 B  are diagrams for explaining an overview of the printing apparatus according to the embodiment.  FIG.  1 A  is a perspective view, and  FIG.  1 B  is a diagram for explaining the configuration of the printing part. Note that the printing apparatus of  FIG.  1 A  and  FIG.  1 B  is an example of the printing apparatus to which the present embodiment can be applied, and the printing apparatus to which the present embodiment can be applied is not limited to the printing apparatus  10 . 
     The printing apparatus  10  illustrated in  FIG.  1 A  and  FIG.  1 B  is what is termed as a multifunction peripheral including a reading part  12 , which is capable of reading a document that is set on a platen glass, and a printing part  14 , which performs printing on a print medium, based on information read by the reading part  12 , information input from an external device, or the like. 
     The reading part  12  is located above the printing apparatus  10 , and the printing part  14  is located below the printing apparatus  10 . The printing part  14  includes an accommodation tray  16 , which accommodates a print medium M, a feeder roller  18 , which feeds a print medium M accommodated in the accommodation tray  16 , and a guide part  20 , which guides a fed print medium M to the printing position at which printing is performed by the print head  26  (described later). Further, the printing part  14  includes a conveyance roller  22 , which conveys a print medium M fed via the guide part  20 , a platen  24 , which supports the print medium M conveyed by the conveyance roller  22 , a print head  26 , which ejects ink onto the print medium M supported by the platen  24 . Moreover, the printing part  14  includes a discharge roller  30 , which discharges the print medium M on which printing has been performed to a discharge tray  28 , an ink storage part  32 , which stores ink to be supplied to the print head  26  via a tube (not illustrated in the drawings). 
     It is both possible that the print head  26  is capable of ejecting ink of multiple colors and is capable of ejecting ink of only one color. Further, a configuration capable of ejecting a treatment liquid for imparting a predetermined effect to an image after printing is possible as well. In a case where multiple types of ink (including a treatment liquid) are ejected, multiple ink storage parts  32  for respectively storing different kinds of ink are to be disposed. Further, the print head  26  is mounted on a carriage  34 . The carriage  34  is configured to be reciprocally movable in the X direction. A print medium M accommodated in the accommodation tray  16  is conveyed in the −Y direction by the feeder roller  18 , makes a U-turn because of the guide part  20 , and is conveyed in the +Y direction by the conveyance roller  22 . 
     In the printing apparatus  10 , the print head  26  ejects ink onto the print medium M supported by the platen  24  while moving via the carriage  34  in the X direction, so as to perform the printing operation for performing printing corresponding to one scan on the print medium M. Next, the conveyance operation for conveying the print medium by a predetermined amount in the +Y direction so that an area on which printing has not been performed at all is located at the position where the print medium M faces the print head  26  is performed. Thereafter, the printing operation is performed again. In this way, the printing apparatus  10  prints a predetermined image on a print medium M by repeatedly executing the printing operation and the conveyance operation. 
     The ink storage part  32  includes an ink containing member  36 , in which ink is contained, and an ink chamber  38 , which stores ink contained in the ink containing member  36 . Here, with reference to  FIG.  2 A  and  FIG.  2 B , the configuration of the ink storage part  32  will be explained.  FIG.  2 A  and  FIG.  2 B  are schematic configuration diagrams of the ink storage part  32 .  FIG.  2 A  indicates a state in which the ink containing member  36  is detached from the ink chamber  38 , and  FIG.  2 B  indicates a state in which the ink containing member  36  is mounted on the ink chamber  38 . 
     The ink storage part  32  is disposed for each type of ink to be ejected from the print head  26 . Note that each ink storage part  32  has the same configuration regardless of the type of ink. In the ink storage part  32 , the ink stored in the ink chamber  38  is supplied to the print head  26  via a tube (not illustrated in the drawings). In a case where ink is supplied from the ink chamber  38  to the print head  26  so that the amount of ink in the ink chamber  38  is reduced, ink is supplied to the ink chamber  38  from the connected ink containing member  36 . 
     The ink containing member  36  includes a main body part  40  and a lid part  42 . Ink is contained inside the main body part  40 . Further, at the bottom section of the main body part  40 , a supply part  44  to be connected to a connecting member  47  (described later) of the ink chamber  38  so as to be capable of supplying ink to the ink chamber  38  is disposed. That is, in the present embodiment, the ink containing member  36  is configured to be detachable from the ink chamber  38  via the supply part  44 . The supply part  44  includes a check valve having a valve spring structure or the like. The lid part  42  is formed with an air communication port  46  that allows the inside and the outside of the ink containing member  36  to communicate with each other. 
     The ink chamber  38  includes the connecting member  47  to be connected to the ink containing member  36  via the supply part  44 . At the bottom section  38   a  inside the ink chamber  38 , a pivot member  48  is disposed. The pivot member  48  is supported by the support member  50  at the bottom section  38   a  in a revolvable manner. Therefore, in a case where the liquid is supplied to the ink chamber  38 , the pivot member  48  is in a state of being immersed in the liquid. Further, inside the ink chamber  38 , a sensor  52  capable of detecting a pivotal movement of the pivot member  48  is disposed above the pivot member  48 . The ink chamber  38  is formed with an air communication port  54  that allows the inside and the outside of the ink chamber  38  to communicate with each other at a position that the liquid surface of the stored ink does not reach. 
     The pivot member  48  includes a float  56  extending in the Y direction, an arm part  58  extending upward (approximately Z direction) from the float  56 , and a detected part  60  located at the tip of the arm part  58 . The float  56  is formed of a material having a specific gravity smaller than that of the ink contained in the ink containing member  36 . Further, the float  56  is supported in a revolvable manner by a shaft  62  extending in the X direction in the support member  50  at the lower end portion on one side of the extending direction (Y direction). The detected part  60  is located on the upper side of the float  56  via the arm part  58 . Therefore, the detected part  60  is configured to be movable according to the pivotal movement of the float  56 . The detected part  60  is formed of a material that can be detected by the sensor  52 . Note that, as will be described later, since the sensor  52  is an optical sensor including a light-emitting part and a light-receiving part in the present embodiment, the detected part  60  is formed of a material that blocks or attenuates the light from the light-emitting part. 
     The sensor  52  is a detection unit that detects the pivotal movement of the pivot member  48 , in order to optically detect that the liquid surface of the ink stored in the ink chamber  38  has reached a predetermined position or higher. More specifically, the sensor  52  includes the light-emitting part (not illustrated in the drawings) and the light-receiving part (not illustrated in the drawings). In  FIG.  2 A  and  FIG.  2 B , the light-emitting part and the light-receiving part are arranged so as to face each other with an interval in the X direction. Note that, in a case where the pivot member  48  makes a pivotal movement, the detected part  60  passes between the light-emitting part and the light-receiving part. Further, the sensor  52  outputs different detection signals according to the light received by the light-receiving part out of the light output from the light-emitting part. 
     Specifically, for example, in a case where the light that is output from the light-emitting part cannot be received by the light-receiving part, that is, in a case where the received-light intensity is lower than a predetermined intensity, the sensor  52  outputs a low-level signal, which represents a signal of a signal level lower than a threshold level. The output low-level signal is received by a control part (not illustrated in the drawings) mounted on the main PCB (not illustrated in the drawings). The control part that has received the low-level signal detects that the height of the liquid surface of ink is equal to or higher than a predetermined position. 
     On the other hand, in a case where the light that is output from the light-emitting part can be received by the light-receiving part, that is, in a case where the received-light intensity is equal to or higher than the predetermined intensity, the sensor  52  outputs a high-level signal, which represents a signal of a signal level equal to or higher than the threshold level. The output high-level signal is received by the control part, and the control part detects that the height of the liquid surface of ink is lower than the predetermined position. 
     In a case where the ink containing member  36  is connected to the connecting member  47  of an ink chamber  38  with no ink stored (see  FIG.  2 A ) via the supply part  44 , the ink inside the ink containing member  36  flows to the inside of the ink chamber  38  via the supply part  44  and the connecting member  47 . In a case where a certain amount of ink is stored in the ink chamber  38 , the buoyancy that acts on the float  56 , which has a specific gravity smaller than that of the ink, exceeds the gravity, so that the pivot member  48  (float  56 ) pivotally moves in the direction of Arrow A. By the pivotal movement of the pivot member  48  in the direction of Arrow A, the detected part  60  moves in the direction of Arrow B. 
     Then, in a case where the height of the liquid surface of the ink in the ink chamber  38  reaches the predetermined position or higher due to a further inflow of ink, the detected part  60  moves in the direction of Arrow B to the position between the light-emitting part and the light-receiving part of the sensor  52 . By the height of the liquid surface of the ink in the ink chamber  38  reaching the predetermined position or higher, it indicates, in other words, that a predetermined amount of ink is stored in the ink chamber  38 . Note that, during the time in which the height of the liquid surface of the ink is equal to or higher than the predetermined position, the detected part  60  stays between the light-emitting part and the light-receiving part (see  FIG.  2 B ). In this way, in a case where the height of the liquid surface of the ink is equal to or higher than the predetermined position, since the light that is output from the light-emitting part is not received by the light-receiving part (or is attenuated before reaching the light-receiving part) due to the detected part  60 , the sensor  52  outputs the low-level signal to the control part. Accordingly, the control part detects that the height of the liquid surface of the ink is equal to or higher than the predetermined position. 
       FIG.  3 A  and  FIG.  3 B  are diagrams for explaining the operation of the pivot member  48  in a case where the amount of ink in the ink chamber  38  is reduced.  FIG.  3 A  is a diagram illustrating the pivot member  48  in a case where the liquid surface of the ink in the ink chamber  38  is equal to or higher than the predetermined position, and  FIG.  3 B  is a diagram illustrating the pivot member  48  in a case where the liquid surface of the ink in the ink chamber  38  is lower than the predetermined position. 
     Due to a supply of ink from the ink chamber  38  to the print head  26 , the amount of ink inside the ink chamber  38  and the ink containing member  36  is reduced, so that the liquid surface of the ink in the ink chamber  38  is lowered (see  FIG.  3 A ). In a case where the amount of ink in the ink chamber  38  is reduced and the amount of stored ink becomes less than a certain amount, the gravity exceeds the buoyancy acting on the float  56 . Accordingly, the pivot member  48  (float  56 ) pivotally moves in the direction of Arrow C. By this pivotal movement of the pivot member  48  in the direction of Arrow C, the detected part  60  moves in the direction of Arrow D. 
     Then, in a case where the height of the liquid surface of the ink in the ink chamber  38  becomes lower than the predetermined position due to a further supply of ink to the print head  26 , the detected part  60  moves in the direction of Arrow D to a position where the detected part  60  is retracted from between the light-emitting part and the light-receiving part of the sensor  52 . Note that, during the time in which the height of the liquid surface of the ink is lower than the predetermined position, the detected part  60  stays at the position where the detected part  60  is retracted from between the light-emitting part and the light-receiving part (see  FIG.  3 B ). In this way, in a case where the height of the liquid surface of the ink is lower than the predetermined position, since the light that is output from the light-emitting part can be received by the light-receiving part (or is not attenuated before reaching the light-receiving part), the sensor  52  outputs the high-level signal to the control part. Accordingly, the control part detects that the height of the liquid surface of the ink is lower than the predetermined position. 
     Here, at the point in time where the printing apparatus  10  detects that the height of the liquid surface of the ink becomes lower than the predetermined position, a notification for prompting the user to replace the ink containing member  36  is provided to a display part  17  (see  FIG.  1 A ) which is disposed on the printing apparatus  10 , for example. The user normally checks the notification displayed on the display part  17  and replaces the ink containing member  36 . However, depending on the usage conditions, the ink containing member  36  may be let stand whereas the height of the liquid surface of the ink has become lower than the predetermined position. In particular, in a case where the liquid surface of the ink has become as low as the shaft  62  (see  FIG.  3 B ), a part of the shaft  62  is exposed to the atmosphere. If this state is further let stand for a long period of time, the ink remaining near the shaft  62  becomes thickened, and finally the ink around the shaft  62  is solidified. Accordingly, there is a possibility that the pivotal movement of the pivot member  48  is hindered, and whether or not the height of the liquid surface of the ink is equal to or higher than the predetermined position, that is, whether or not the remaining ink amount of the ink chamber  38  is equal to or lower than a predetermined amount cannot be accurately detected. 
     Therefore, in the present embodiment, a magnetic member  64  is disposed on the first side surface  56   a  of the float  56 , and an electromagnet  66  is disposed at a position facing the magnetic member  64  via the wall of the ink chamber  38  (see  FIG.  2 A ,  FIG.  2 B ,  FIG.  3 A , and  FIG.  3 B ). This electromagnet  66  is controlled by the control part to be energized, so that a magnetic force is generated. The magnetic member  64  and the electromagnet  66  configure a pivot unit. The first side surface  56   a  of the float  56 , on which the magnetic member  64  is disposed, is an end surface corresponding to the +Y direction in the vicinity of the support member  50 . That is, with respect the float  56 , the magnetic member  64  is disposed on the side closer to the support member  50  than to the center of gravity of the float  56 . With such a configuration, the pivot member  48  is attracted to the electromagnet  66  side by the magnetic force of the electromagnet  66 , so that the posture of the detected part  60  changes from a posture in which the detected part  60  is retracted from between the light-emitting part and the light-receiving part of the sensor  52  to a posture in which the detected part  60  is located therebetween. Note that, by arranging the magnetic member  64  on the first side surface  56   a , the effect which is caused on the pivotal movement of the pivot member  48  by the increase in gravity of the float  56  due to the magnetic member  64  can be prevented. 
       FIG.  4 A  and  FIG.  4 B  are diagrams for explaining forced pivotal movement that the pivot member  48  is made to perform by use of the electromagnet  66 .  FIG.  4 A  is a diagram illustrating a posture of the pivot member  48  in a case where the height of the liquid surface of the ink is lower than the predetermined position, and  FIG.  4 B  is a diagram illustrating a posture of the pivot member  48  in a case where the electromagnet  66  is energized. In a case where the height of the liquid surface of the ink in the ink chamber  38  becomes lower than the predetermined position, the gravity exceeds the buoyancy acting on the float  56  of the pivot member  48  as illustrated in  FIG.  4 A , so that the detected part  60  turns into a posture in which the detected part  60  is retracted from between the light-emitting part and the light-receiving part of the sensor  52 . As described above, if this state is let stand for a long period of time, there is a possibility that the ink around the shaft  62  becomes thickened and solidified, so that the pivotal movement of the pivot member  48 , which is disposed on the shaft  62  in a revolvable manner, is hindered by the thickened and solidified ink. 
     Therefore, by energizing the electromagnet  66  so that a magnetic force is generated in the electromagnet  66 , the magnetic member  64  disposed on the first side surface  56   a  of the float  56 , which faces the ink chamber  38  via the wall, is attracted to the electromagnet  66  side. In a case where the magnetic member  64  is attracted to the electromagnet  66  side, a force in the direction of Arrow A is generated on the pivot member  48 , so that the pivot member  48  is forced to make a pivotal movement. Accordingly, the pivot member  48  turns into a posture in which the detected part  60  is located between the light-emitting part and the light-receiving part of the sensor  52  or at a position near there (see  FIG.  4 B ). Thereafter, by de-energizing the electromagnet  66 , the magnetic force of the electromagnet  66  is disappeared, so that the attraction of the magnetic member  64  toward the electromagnet  66  side is stopped. Accordingly, a force in the direction of Arrow C is generated on the pivot member  48  due to its own weight. Then, the pivot member  48  pivotally moves in the direction of Arrow C, so that the detected part  60  turns into a posture in which the detected part  60  is retracted from between the light-emitting part and the light-receiving part of the sensor  52  (see  FIG.  4 A ). In this way, in the present embodiment, the magnetic member  64  and the electromagnet  66  function as a pivot unit that forces the pivot member  48  to make a pivotal movement. 
     In this way, the forced pivotal movement, in which energization of the electromagnet  66  for forcing the pivot member  48  to pivotally move in the direction of Arrow A and then de-energization of the electromagnet  66  for making the pivot member  48  pivotally move in the direction of Arrow C by its own weight are alternately and repeatedly performed, is executed. Accordingly, it is possible to diffuse the thickened ink accumulated near the shaft  62 . Therefore, the thickening of the ink in the vicinity of the shaft  62  is eliminated, so that the pivotal movement of the pivot member  48  is prevented from being hindered by thickened and solidified ink. Note that, during the control for energizing the electromagnet  66 , the sensor  52  does not transmit a signal to the control part, or the control part does not receive a signal from the sensor  52 . 
     The forced pivotal movement of the pivot member  48  by use of the electromagnet  66  can be executed at various timings. For example, the forced pivotal movement is executed for a certain period of time at a timing after a prompt of replacement of the ink containing member  36  and where a predetermined period of time elapses without replacement of the ink containing member  36 . Note that the timing and length of the forced pivotal movement are set according to the type of ink to be used, the working environment, etc. 
     Although not particularly described in the above-described embodiment, it is also possible that the magnetic member  64  is formed on the full surface or a part of the first side surface  56   a  of the float  56  as long as the pivot member  48  is revolvable because of a magnetic force generated by the electromagnet  66 . Further, the positional relationship between the magnetic member  64  and the electromagnet  66  is not limited to that in the above-described embodiment. That is, the arrangement positions of the magnetic member  64  and the electromagnet  66  can be anywhere as long as the pivot member  48  can be displaced by energization control on the electromagnet  66  between a posture in which the detected part  60  is retracted from between the light-emitting part and the light-receiving part of the sensor  52  and a posture in which the detected part  60  is located therebetween. 
     As explained above, in the printing apparatus  10 , the magnetic member  64  is disposed on the pivot member  48 , which is disposed in the ink chamber  38 , and the electromagnet  66  is disposed at the position facing the magnetic member  64  via the wall of the ink chamber  38 . Accordingly, it is possible to force the pivot member  48  to make a pivotal movement, so that the thickened ink around the shaft  62 , which supports the pivot member  48  in a revolvable manner, can be diffused. Therefore, it is possible to prevent the pivotal movement of the pivot member  48  from being hindered by thickened ink and solidified ink around the shaft  62 . Therefore, in the printing apparatus  10 , even though the ink around the shaft  62  in the support member  50 , which supports the pivot member  48  in a revolvable manner, is thickened or solidified, it is possible to prevent deterioration in the function of detecting the ink remaining amount. 
     Second Embodiment 
     Next, with reference to  FIG.  5 A  and  FIG.  5 B , an explanation will be given of a printing apparatus according to the second embodiment. Note that, in the following explanation, as in the above-described first embodiment, a printing apparatus that ejects ink onto a print medium for printing is taken as an example for the sake of explanation. In addition, the same or corresponding configurations as those of the printing apparatus according to the above-described first embodiment are assigned with the same signs, so as to omit detailed explanations thereof as appropriate. 
     The printing apparatus  10  according to the second embodiment is different from the printing apparatus according to the above-described first embodiment in that a flow is generated to the ink so as to make the pivot member  48  pivotally move in a state where the height of the liquid surface of the ink in the ink chamber  38  is equal to or higher than a predetermined position. 
       FIG.  5 A  and  FIG.  5 B  are diagrams for explaining forced pivotal movement according to the second embodiment.  FIG.  5 A  is a diagram illustrating a posture of the pivot member  48  in a case where the height of the liquid surface of the ink is equal to or higher than the predetermined position, and  FIG.  5 B  is a diagram illustrating a posture of the pivot member  48  in a case where an ink flow is generated. Specifically, the printing apparatus  10  according to the second embodiment includes an ink flow generation part  68  that generates a flow to the stored ink in the ink chamber  38 . Further, the pivot member  48  includes a receiver part  70  that receives the ink flow generated by the ink flow generation part  68  so that the pivot member  48  is forced to make a pivotal movement. Note that, in the printing apparatus  10  according to the present embodiment, the magnetic member  64  and the electromagnet  66  are not disposed. 
     For example, the ink flow generation part  68  is configured to be capable of generating an ink flow by ejecting ink into the stored ink in the ink chamber  38  in which ink is stored. The specific configuration for ejecting ink may be, but not limited to, a configuration using a solenoid valve, a piezo element, or thermal foaming. Further, the configuration of the ink flow generation part  68  is not limited to a configuration in which an ink flow is generated by ejecting ink, but can be any configuration as long as it is possible to generate a flow to the ink stored in the ink chamber  38 . The driving of the ink flow generation part  68  is controlled by the control part so as to generate an ink flow. 
     In the present embodiment, the ink flow generation part  68  is disposed in the vicinity of the end portion on another side of the float  56  which is not supported by the support member  50  at the bottom section  38   a  of the ink chamber  38  Further, the ink flow generation part  68  is disposed at a position that overlaps with the float  56  in the Y direction and does not overlap with the float  56  in the X direction. Accordingly, the ink flow generated by the ink flow generation part  68  does not directly hit the float  56 . 
     The receiver part  70  is fixedly disposed on the second side surface  56   b  of the float  56 , which extends in the Y direction, at a position that overlaps with the ink flow generation part  68  in the X direction and the Y direction. The receiver part  70  has a shape that receives the ink flow generated by the ink flow generation part  68 , so as to be capable of making the pivot member  48  pivotally move from a posture in which the detected part  60  is located between the light-emitting part and the light-receiving part of the sensor  52  to a posture in which the detected part  60  is retracted from therebetween. Note that it is both possible that the ink flow generation part  68  and the receiver part  70  are disposed on one side of the float  56  and on both sides of the float  56  with respect to the X direction. 
     As for the above-described configuration, a case in which forced pivotal movement of the pivot member  48  is performed will be explained. As illustrated in  FIG.  5 A , if the height of the liquid surface of the ink in the ink chamber  38  is equal to or higher than the predetermined position, such a force to make the pivot member  48  pivotally move in the direction of Arrow A is generated due to the buoyancy generated to the float  56 . At this time, if thickened ink or the like is attached around the shaft  62 , the pivot member  48  may not be able to pivotally move to make the detected part  60  properly located between the light-emitting part and the light-receiving part of the sensor  52 . 
     Therefore, from this state, an ink flow is generated by the ink flow generation part  68 . Then, the receiver part  70  disposed on the second side surface  56   b  of the float  56  receives the generated ink flow. Accordingly, a force in the direction of Arrow C is generated to the pivot member  48 , so that the pivot member  48  is forced to make a pivotal movement so as to be in a posture in which the detected part  60  is completely retracted from between the light-emitting part and the light-receiving part of the sensor  52  (see  FIG.  5 B ). Thereafter, the driving of the ink flow generation part  68  is stopped. Accordingly, the ink flow disappears, and a force in the direction of Arrow A is generated to the pivot member  48  because of the buoyancy of the float  56 , so that the pivot member  48  makes a pivotal movement so as to be in a posture in which the detected part  60  is located between the light-emitting part and the light-receiving part of the sensor  52  or in a posture similar to that (see  FIG.  5 A ). In this way, in the present embodiment, the ink flow generation part  68  and the receiver part  70  function as a pivot unit that forces the pivot member  48  to make a pivotal movement. 
     In this way, the forced pivotal movement, in which driving of the ink flow generation part  68  for forcing the pivot member  48  to pivotally move in the direction of Arrow C and stopping of the ink flow generation part  68  for making the pivot member  48  pivotally move in the direction of Arrow A because of the buoyant of the float  56  are alternately and repeatedly performed, is executed. Accordingly, it is possible to diffuse the thickened ink accumulated near the shaft  62 . Therefore, the thickening of the ink in the vicinity of the shaft  62  is eliminated, so that it is possible that the pivotal movement of the pivot member  48  is prevented from being hindered by thickened or solidified ink. Note that, during the control for driving the ink flow generation part  68 , the sensor  52  does not transmit a signal to the control part, or the control part does not receive a signal from the sensor  52 . 
     Further, the forced pivotal movement of the pivot member  48  by use of the ink flow generation part  68  can be executed at various timings. For example, the forced pivotal movement is executed for a certain period of time at a timing where the ink containing member  36  is replaced and such an amount of ink that the liquid surface becomes equal to or higher than the predetermined position is stored in the ink chamber  38  (for example, the determination is made based on the time period after an ink containing member  36  is connected to the ink chamber  38 ). Note that the timing and length of the forced pivotal movement are set according to the type of ink to be used, the working environment, etc. 
     Although not particularly described in the above-described embodiment, the ink flow generation part  68  and the receiver part  70  are not limited to those in the above-described embodiment. That is, the ink flow generation part  68  and the receiver part  70  can be arranged in any ways as long as the pivot member  48  can be displaced by the generated ink flow from a posture in which the detected part  60  is located between the light-emitting part and the light-receiving part of the sensor  52  to a posture in which the detected part  60  is retracted from therebetween. 
     Further, although the receiver part  70  is configured to receive an ink flow generated by the ink flow generation part  68  so that the pivot member  48  makes a pivotal movement in the above-described embodiment, the present embodiment is not limited as such. That is, it is also possible that at least one of the float  56 , the arm part  58 , and the detected part  60  is configured to directly receive an ink flow generated by the ink flow generation part  68  so that the pivot member  48  makes a pivotal movement. 
     As explained above, in the printing apparatus  10 , the ink flow generation part  68 , which generates an ink flow, and the receiver part  70 , which is capable of receiving the generated ink flow so as to make the pivot member  48  pivotally move, are disposed. Accordingly, it is possible to force the pivot member  48  to make a pivotal movement in a state where such an amount of ink that the liquid surface is equal to or higher than the predetermined position is stored in the ink chamber  38 , so that thickened ink around the shaft  62  can be diffused. Therefore, it is possible to prevent the pivotal movement of the pivot member  48  from being hindered by thickened ink and solidified ink around the shaft  62 . Therefore, in the printing apparatus  10 , even though the ink around the shaft  62  in the support member  50 , which supports the pivot member  48  in a revolvable manner, is thickened or solidified, it is possible to prevent deterioration in the function of detecting the ink remaining amount. 
     Other Embodiments 
     Note that the above-described embodiments may be modified as shown in the following (1) through (5). 
     (1) Although a mechanism for determining whether or not the height of the liquid surface of ink is equal to or higher than a predetermined position, that is, for determining the ink remaining amount is disposed in the ink chamber  38  in the above-described embodiments, the present embodiments are not limited as such. That is, it is also possible that the mechanism for determining the ink remaining amount, such as the pivot member  48  and a mechanism for making the pivot member  48  pivotally move, is disposed in the ink containing member  36 . Furthermore, although the electromagnet  66  is disposed outside the ink chamber  38  in the above-described first embodiment, the present embodiment is not limited as such. That is, it is also possible that the electromagnet  66  is disposed inside the ink chamber  38 . 
     (2) Although whether or not the height of the liquid surface of the ink stored in the ink chamber  38  is equal to or higher than a predetermined position is determined by the pivot member  48  and the sensor  52  in the above-described embodiments, the configuration for detecting the ink remaining amount of the ink chamber  38  is not limited as such. That is, such a configuration in which a sensor that is capable of detecting the rotation angle of the pivot member  48  relative to the reference position is disposed so as to detect the remaining amount of ink stored in the ink chamber  38 , based on the rotation angle of the pivot member  48 , in a phased manner or a continuous manner. 
     (3) The present disclosure is not only applied to a printing apparatus that performs printing by ejecting ink, but the present disclosure can be widely applied as a liquid ejection apparatus that ejects various kinds of liquid from a liquid ejection head. Further, in the above-described embodiment, the printing apparatus  10  is what is termed as a serial scan type printing apparatus that ejects ink from a print head, which moves in the X direction, onto a print medium, which is conveyed in the Y direction, the printing apparatus  10  is not limited as such. That is, what is termed as a full-line type printing apparatus, which uses a long print head extending over the whole area in the width direction of the printing area in a print medium, can be used as well. 
     (4) Although a signal is not transmitted from the sensor  52  to the control part or a signal from the sensor  52  is not received by the control part during the time where the forced pivotal movement of the pivot member  48  is executed in the above-described embodiments, the present embodiments are not limited as such. That is, it is also possible that the forced pivotal movement is terminated according to a signal in the control part, which is output from the sensor  52 . Accordingly, for example, in a case where reception of a low-level signal during energization to the electromagnet  66  and reception of a high-level signal during de-energization to the electromagnet  66  are repeated by a set number of times, it is determined that thickening of the ink in the vicinity of the shaft  62  is eliminated, and the forced pivotal movement is terminated. 
     (5) The above-described embodiments and various forms shown in (1) through (4) may be combined as appropriate. 
     While the present disclosure has been described with reference to exemplary embodiments, it is to be understood that the disclosure 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. 2020-057121 filed Mar. 27, 2020, which is hereby incorporated by reference wherein in its entirety.