Patent Publication Number: US-11020980-B2

Title: Droplet discharge apparatus

Description:
The present application is based on, and claims priority from JP Application Serial Number 2019-061301, filed Mar. 27, 2019, the disclosure of which is hereby incorporated by reference herein in its entirety. 
     BACKGROUND 
     1. Technical Field 
     The present disclosure relates to a droplet discharge apparatus. 
     2. Related Art 
     The droplet discharge apparatus is an apparatus that discharges liquid droplets from fine nozzles and attaches the liquid droplets to a recording medium. The droplet discharge apparatus has a characteristic to be able to quickly record a high-resolution and high-quality image. In an ink jet recording method using the droplet discharge apparatus, an image is formed by discharging inks of a plurality of colors. 
     The droplet discharge apparatus is also used for textile printing. The textile printing may be performed by, for example, using an ink set of colors including cyan (C), magenta (M), yellow (Y), black (BK), and the like, and mixing colors and adjusting size and density of dots on the textile. However, a desired color may not be obtained by such adjusting. In such a case, an ink for obtaining a desired color is prepared in advance and the ink may be discharged from the droplet discharge apparatus. Therefore, a droplet discharge apparatus is required where a different color ink or an ink having different components can be replaced so as to be able to use a color other than C, M, Y, and BK. 
     JP-A-2013-129081 discloses a technique where ink flow paths of Y, M, C, and BK are coupled to one head, and when replacing ink to be supplied to the head, the ink is returned to a liquid storage tank and an empty prevention liquid that prevents a head flow path from being empty is supplied to the head flow path. 
     However, when ink is to be prepared in advance in the technique described in JP-A-2013-129081, the liquid storage tank is required to be provided for each color. Further, when the amount of ink to be used is large as in a printing field, the size of the tank needs to be large, and waste often occurs in the prepared ink when replacing the ink. 
     SUMMARY 
     According to an aspect of the present disclosure, a droplet discharge apparatus includes 
     a first head, 
     a first ink container that stores first ink to be supplied to the first head, 
     a second head, 
     a second ink container that stores second ink to be supplied to the second head, 
     a cleaning liquid container that stores cleaning liquid, 
     a common flow path system that couples the first ink container with the second ink container, 
     a cleaning liquid flow path that couples the common flow path system with the cleaning liquid container, 
     a first valve that controls a liquid flow rate between the common flow path system and the first ink container, 
     a second valve that controls a liquid flow rate between the common flow path system and the second ink container, 
     a third valve that controls a liquid flow rate between the common flow path system and the cleaning liquid flow path, 
     a first pomp that is provided in the common flow path system and feeds the first ink from the first ink container to the second ink container through the common flow path system, 
     a second pomp that feeds the cleaning liquid from the cleaning liquid container to the first ink container through the cleaning liquid flow path and the common flow path system, and 
     a control unit, and 
     the control unit 
     transfers the first ink stored in the first ink container to the second ink container through the common flow path system by controlling the first valve, the second valve, the third valve, and the first pomp, and 
     transfers the cleaning liquid stored in the cleaning liquid container to the first ink container through the cleaning liquid flow path and the common flow path system by controlling the first valve, the second valve, the third valve, and the second pomp. 
     According to the aspect described above, the droplet discharge apparatus includes 
     a waste liquid container, 
     a waste liquid flow path system that couples the common flow path system with the waste liquid container, 
     a fourth valve that controls a liquid flow rate between the common flow path system and the waste liquid flow path system, and 
     a third pomp that feeds the cleaning liquid transferred to the first ink container from the first ink container to the waste liquid container through the waste liquid flow path system, and 
     the control unit 
     may transfer the cleaning liquid transferred to the first ink container to the waste liquid container through the waste liquid flow path system by controlling the first valve, the fourth valve, and the third pomp. 
     According to any one of the aspects described above, the droplet discharge apparatus includes 
     a fourth pomp that feeds the cleaning liquid from the cleaning liquid container to the waste liquid container through the cleaning liquid flow path, the common flow path system, and the waste liquid flow path system, and 
     the control unit 
     may transfer the cleaning liquid stored in the cleaning liquid container to the waste liquid container through the cleaning liquid flow path, the common flow path system, and the waste liquid flow path system by controlling the first valve, the second valve, the third valve, the fourth valve, and the fourth pomp. 
     According to any one of the aspects described above, in the droplet discharge apparatus, 
     the waste liquid container may store liquid discharged from the first head. 
     According to any one of the aspects described above, the droplet discharge apparatus includes 
     a first flow path system that couples the first head with the first ink container, and 
     a fifth valve provided in the first flow path system, and 
     the control unit 
     may transfer the cleaning liquid transferred to the first ink container to the first head through the first flow path system by controlling the fifth valve. 
     According to any one of the aspects described above, in the droplet discharge apparatus, 
     the control unit 
     may reduce a liquid flow rate of the first flow path system by controlling the fifth valve when transferring the cleaning liquid stored in the cleaning liquid container to the first ink container through the cleaning liquid flow path and the common flow path system. 
     According to any one of the aspects described above, in the droplet discharge apparatus, 
     the first flow path system includes 
     a first auxiliary container coupled to the first head, and 
     a fifth pomp provided between the first auxiliary container and the first ink container, and 
     the control unit 
     may collect the first ink stored in the first auxiliary container into the first ink container by controlling the fifth pomp before transferring the first ink stored in the first ink container to the second ink container through the common flow path system. 
     According to any one of the aspects described above, the droplet discharge apparatus includes 
     a second flow path system that couples the second head with the second ink container, 
     a sixth valve provided in the second flow path system, 
     a first sensor that detects an amount of liquid in the first ink container, 
     a second sensor that detects an amount of liquid in the second ink container, and 
     a second auxiliary container coupled to the second head, and 
     the control unit 
     may transfer the second ink in the second ink container to the second auxiliary container by controlling the sixth valve when a total amount of the amount of liquid in the first ink container detected by the first sensor and the amount of liquid in the second ink container detected by the second sensor exceeds a predetermined amount before transferring the first ink stored in the first ink container to the second ink container through the common flow path system. 
     According to any one of the aspects described above, the droplet discharge apparatus includes 
     a second flow path system that couples the second head with the second ink container, 
     a sixth valve provided in the second flow path system, 
     a second sensor that detects an amount of liquid in the second ink container, and 
     a second auxiliary container coupled to the second head, and 
     the control unit 
     may transfer the second ink in the second ink container to the second auxiliary container by controlling the sixth valve when the second sensor detects that the amount of liquid in the second ink container exceeds a predetermined amount. 
     According to any one of the aspects described above, the droplet discharge apparatus includes 
     a first sensor that detects an amount of liquid in the first ink container, and 
     a second sensor that detects an amount of liquid in the second ink container, and 
     the control unit 
     may transfer the first ink stored in the first ink container to the second ink container through the common flow path system when the amount of liquid in the first ink container detected by the first sensor is smaller than the amount of liquid in the second ink container detected by the second sensor. 
     According to any one of the aspects described above, in the droplet discharge apparatus, 
     the first ink and the second ink may be the same ink. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a schematic diagram of a main part of a droplet discharge apparatus according to an embodiment. 
         FIG. 2  is a schematic diagram showing a part of a control procedure of the main part of the droplet discharge apparatus according to the embodiment. 
         FIG. 3  is a schematic diagram showing a part of the control procedure of the main part of the droplet discharge apparatus according to the embodiment. 
         FIG. 4  is a schematic diagram showing a part of the control procedure of the main part of the droplet discharge apparatus according to the embodiment. 
         FIG. 5  is a schematic diagram showing a part of the control procedure of the main part of the droplet discharge apparatus according to the embodiment. 
         FIG. 6  is a schematic diagram showing a part of the control procedure of the main part of the droplet discharge apparatus according to the embodiment. 
         FIG. 7  is a schematic diagram showing a part of the control procedure of the main part of the droplet discharge apparatus according to the embodiment. 
         FIG. 8  is a schematic diagram showing a part of the control procedure of the main part of the droplet discharge apparatus according to the embodiment. 
         FIG. 9  is a schematic diagram showing a part of the control procedure of the main part of the droplet discharge apparatus according to the embodiment. 
     
    
    
     DESCRIPTION OF EXEMPLARY EMBODIMENTS 
     Hereinafter, an embodiment of the present disclosure will be described. The embodiment described below describes an example of the present disclosure. The present disclosure is not limited at all by the embodiment described below. The present disclosure includes various modified examples implemented within the scope not changing the gist of the present disclosure. All of the configurations described below are not necessarily essential components of the present disclosure. 
     1. Configuration of Droplet Discharge Apparatus 
       FIG. 1  is a schematic diagram of a main part of a droplet discharge apparatus  100  according to the embodiment. The droplet discharge apparatus  100  includes a first head  11 , a first ink container  21  that stores first ink to be supplied to the first head  11 , a second head  12 , a second ink container  22  that stores second ink to be supplied to the second head  12 , a cleaning liquid container  32  that stores cleaning liquid, a common flow path system  42  that couples the first ink container  21  with the second ink container  22 , a cleaning liquid flow path  44  that couples the common flow path system  42  with the cleaning liquid container  32 , a first valve  61  that controls a liquid flow rate between the common flow path system  42  and the first ink container  21 , a second valve  62  that controls a liquid flow rate between the common flow path system  42  and the second ink container  22 , a third valve  63  that controls a liquid flow rate between the common flow path system  42  and the cleaning liquid flow path  44 , a first pomp  71  that is provided in the common flow path system  42  and feeds the first ink from the first ink container  21  to the second ink container  22  through the common flow path system  42 , a second pomp  72  that feeds the cleaning liquid from the cleaning liquid container  32  to the first ink container  21  through the cleaning liquid flow path  44  and the common flow path system  42 , and a control unit not shown in the figures. 
     The droplet discharge apparatus  100  further includes a first flow path system  51  that couples the first head  11  with the first ink container  21 , a first auxiliary container  81  that is coupled to the first head  11 , a second flow path system  52  that couples the second head  12  with the second ink container  22 , a second auxiliary container  82  that is coupled to the second head  12 , a first sensor  91  that detects the amount of liquid in the first ink container  21 , a second sensor  92  that detects the amount of liquid in the second ink container  22 , a waste liquid container  34 , a waste liquid flow path system  46  that couples the common flow path system  42  with the waste liquid container  34 , a fourth valve  64  that controls a liquid flow rate between the common flow path system  42  and the waste liquid flow path system  46 , a fifth valve  65  provided in the first flow path system  51 , a sixth valve  66  provided in the second flow path system  52 , a third pomp  73  that feeds the cleaning liquid transferred to the first ink container  21  from the first ink container  21  to the waste liquid container  34  through the common flow path system  42  and the waste liquid flow path system  46 , a fourth pomp  74  that feeds the cleaning liquid from the cleaning liquid container  32  to the waste liquid container  34  through the cleaning liquid flow path  44 , the common flow path system  42 , and the waste liquid flow path system  46 , and a fifth pomp  75  provided between the first auxiliary container  81  and the first ink container  21 . 
     The droplet discharge apparatus  100  further includes the first sensor  91  that detects the amount of liquid in the first ink container  21  and the second sensor  92  that detects the amount of liquid in the second ink container  22 . The droplet discharge apparatus  100  further includes suction caps  95 , which suck liquid in the first head  11  and the second head  12  from nozzles of the first head  11  and the second head  12 , respectively. The suction caps  95  are coupled to a suction flow path  48  that depressurizes the insides of the suction caps  95  when the suction caps  95  cap the heads. The suction flow path  48  is provided with a sixth pomp  96 . The liquid transferred from the suction caps  95  is configured to be collected to the waste liquid container  34 . 
     1.1. Head 
     The droplet discharge apparatus  100  has a plurality of heads. The number of heads included in the droplet discharge apparatus  100  may be arbitrary as long as the number is two or more. The head discharges liquid such as ink supplied to the head as droplets from fine nozzles. The droplets discharged from the head is attached to, for example, a recording medium not shown in the figures. Thereby, an image can be recorded on the recording medium, or the recording medium can be printed. A method of the head is not limited, but the method is, for example, a piezoelectric method. These heads may discharge different colors of inks, respectively, or a plurality of heads may discharge the same color of ink. 
     In the description below, one of the plurality of heads included in the droplet discharge apparatus  100  is referred to as the “first head  11 ” and one of the heads other than the first head  11  is referred to as the “second head  12 ”. 
     1.2. Ink and Cleaning Liquid 
     The ink used in the droplet discharge apparatus  100  is not limited as long as the ink can be discharged as droplets from the head described above. As the types of ink, there are, for example, dye ink, pigment ink, UV ink, and the like. The colors of ink are not particularly limited and may be cyan, magenta, yellow, black, and the like, or may be prepared special colors. The ink may be treatment liquid containing no color material or the like. The ink may contain an organic solvent, a surfactant, and other additive agents, which are commonly used. 
     In the description below, the ink to be supplied to the first head  11  is referred to as the “first ink”, and the ink to be supplied to the second head  12  is referred to as the “second ink”. In the present embodiment, as described below, when the first ink container  21  is cleaned, the first ink is transferred to the second ink container  22 , so that it is preferable that the first ink and the second ink are the same. By doing so, the second ink stored in the second ink container  22  can be maintained in a predetermined color even when the first ink is mixed in the second ink. 
     The cleaning liquid can clean the containers, the flow paths, and the like. In the droplet discharge apparatus  100 , the cleaning liquid is stored in the cleaning liquid container  32  and is introduced to the common flow path system  42 , the first ink container  21 , the first head  11 , and the like through the cleaning liquid flow path  44  as needed. Thereby, containers and the like through which the cleaning liquid passes are cleaned. The composition of the cleaning liquid is, for example, water or organic solvent, and may contain additive agents such as a surfactant as needed. 
     In the present specification, at least one of the ink, the cleaning liquid, and a mixture liquid of the ink and the cleaning liquid may be referred to as “liquid”. 
     1.3. Container 
     The droplet discharge apparatus  100  includes a plurality of ink containers that store ink to be supplied to the head. The number of the ink containers may be the same as the number of the heads. The ink container stores ink and supplies the ink to a corresponding head. When replacing the ink, a predetermined ink is introduced to the ink container after the cleaning liquid is introduced to the ink container and the ink container is cleaned. 
     In the droplet discharge apparatus  100 , the ink container is not configured to be easily removed from the apparatus in such a manner as to remove a so-called cartridge, and is configured so that a color of ink to be discharged from the head is changed by replacing the stored ink. In the droplet discharge apparatus  100 , the ink container is a so-called big tank and has a capacity larger than that of the cartridge. 
     In the description below, the ink container corresponding to the “first head  11 ” of the plurality of ink containers provided in the droplet discharge apparatus  100  is referred to as the “first ink container  21 ” and the ink container corresponding to the “second head  12 ” is referred to as the “second ink container  22 ”. 
     The droplet discharge apparatus  100  further includes the cleaning liquid container  32  that stores the cleaning liquid and the waste liquid container  34  that stores liquid in addition to the containers described above. The cleaning liquid container  32  stores the cleaning liquid described above. The waste liquid container  34  stores liquid that is no longer required, such as ink, a mixture liquid of ink and cleaning liquid, and cleaning liquid. 
     The droplet discharge apparatus  100  further includes the first auxiliary container  81  that is coupled to the first head  11  and the second auxiliary container  82  that is coupled to the second head  12 . The first auxiliary container  81  and the second auxiliary container  82  are included in the first flow path system  51  and the second flow path system  52 , respectively, and stores the first ink and the second ink supplied from the first ink container  21  and the second ink container  22 , respectively. Both the first auxiliary container  81  and the second auxiliary container  82  are open type, and thereby the pressures of ink applied to the first head  11  and the second head  12  are adjusted. Further, because of the open type, liquid can be sucked to an end side of the first flow path system  51 . 
     1.4. Flow Path and Flow Path System 
     The droplet discharge apparatus  100  includes the common flow path system  42  that couples the first ink container  21  with the second ink container  22 , the cleaning liquid flow path  44  that couples the common flow path system  42  with the cleaning liquid container  32 , the first flow path system  51  that couples the first head  11  with the first ink container  21 , the second flow path system  52  that couples the second head  12  with the second ink container  22 , and the waste liquid flow path system  46  that couples the common flow path system  42  with the waste liquid container  34 . 
     Each of the first flow path system  51 , the second flow path system  52 , the common flow path system  42 , the cleaning liquid flow path  44 , and the waste liquid flow path system  46  is composed of a tube, a pipe, a combination of these, or the like. Each of these flow paths and flow path systems can cause liquid to flow. Arrangement and the like of these flow paths and flow path systems are optional and are not limited as long as they can be coupled in a predetermined manner. 
     1.5. Valves 
     The droplet discharge apparatus  100  includes the first valve  61  that controls the liquid flow rate between the common flow path system  42  and the first ink container  21 , the second valve  62  that controls the liquid flow rate between the common flow path system  42  and the second ink container  22 , the third valve  63  that controls the liquid flow rate between the common flow path system  42  and the cleaning liquid flow path  44 , the fourth valve  64  that controls the liquid flow rate between the common flow path system  42  and the waste liquid flow path system  46 , the fifth valve  65  provided in the first flow path system  51 , and the sixth valve  66  provided in the second flow path system  52 . 
     Each of these valve is a valve or the like. As the valve, any unit that can adjust a flow rate or select a flow path is appropriately used. Examples of the valve that selects a flow path include a three-way cock, a three-way valve, and the like. Although  FIG. 1  shows an example in which a three-way cock is used as each valve, one three-way cock may be replaced with a plurality of valves. 
     The valve can select a flow path and change the magnitude of liquid flow rate and the like based on a signal from the control unit. 
     1.6. Pomps 
     The droplet discharge apparatus  100  includes the first pomp  71  that is provided in the common flow path system  42  and feeds the first ink from the first ink container  21  to the second ink container  22  through the common flow path system  42 , the second pomp  72  that feeds the cleaning liquid from the cleaning liquid container  32  to the first ink container  21  through the cleaning liquid flow path  44  and the common flow path system  42 , the third pomp  73  that feeds the cleaning liquid transferred to the first ink container  21  from the first ink container  21  to the waste liquid container  34  through the common flow path system  42  and the waste liquid flow path system  46 , the fourth pomp  74  that feeds the cleaning liquid from the cleaning liquid container  32  to the waste liquid container  34  through the cleaning liquid flow path  44 , the common flow path system  42 , and the waste liquid flow path system  46 , and the fifth pomp  75  provided between the first auxiliary container  81  and the first ink container  21 . 
     A specific example of these pomps is a pump. The type of pump is not particularly limited. A liquid feeding direction of the pump is appropriately designed. A pump whose liquid feeding direction can be selected may be used, and when such a pump is used, the number of the pumps may be reduced. In  FIG. 1 , a pomp and a valve are provided in one liquid flow passage for explanation. However, the pomp may double as the valve. 
     The pomp changes a liquid flow rate, a liquid feeding direction, and the like based on a signal from the control unit. 
     1.7. Other Configurations 
     The droplet discharge apparatus  100  includes the first sensor  91  that detects the amount of liquid in the first ink container  21  and the second sensor  92  that detects the amount of liquid in the second ink container  22 . Signals corresponding to each the amount of liquid detected by each sensor are referred to by the control unit. 
     The droplet discharge apparatus  100  has suction caps  95 , each of which sucks liquid in a head from nozzles of the head. The suction cap  95  is provided corresponding to each head. The suction cap  95  is coupled with the suction flow path  48  that depressurizes the inside of the suction cap  95  when the suction cap  95  caps the head. The suction flow path  48  is provided with the sixth pomp  96  which is configured so that liquid sucked to the suction flow path  48  is transferred to the waste liquid container  34 . The liquid transferred from the suction cap  95  may be collected to a container different from the waste liquid container  34 . 
     The droplet discharge apparatus  100  is provided with, for example, a mechanism that relatively moves the head and a recording medium in addition to the configuration described above, so that the droplet discharge apparatus  100  can perform ink jet type recording on the recording medium. 
     1.8. Control Unit 
     The droplet discharge apparatus  100  has the control unit not shown in the figures. The valves, the pomps, the caps, the sixth pomp  96 , and the like are controlled based on a signal from the control unit. Further, the control unit can acquire a signal from each sensor and control each component based on the acquired signal. 
     2. Control of Droplet Discharge Apparatus 
     The droplet discharge apparatus  100  of the present embodiment can easily change the liquid discharged from the head to a different liquid. Hereinafter, an example will be described where the first ink and the second ink are the same ink, the first ink in the first ink container  21  is removed, and the first ink container  21  is cleaned, so that ink different from the first ink and the second ink can be introduced into the first ink container  21 . 
       FIGS. 2 to 4  are schematic diagrams showing a procedure where the first ink and the second ink are the same ink, the first ink in the first ink container  21  is removed, and the first ink container  21  is cleaned. 
       FIG. 2  shows a state where the first ink is stored in the first ink container  21 , the first ink is discharged from the first head  11 , the first ink is stored in the second ink container  22 , and the first ink is discharged from the second head  12 .  FIG. 2  shows three pairs of ink and ink container. An arbitrary ink is discharged from a head of a third pair. There may be four or more pairs of head and ink container. 
     In  FIG. 2 , each valve is a valve or a three-way valve, and an arrangement of each valve is indicated by a circular mark. A flow passage of the valve is displayed by a solid line in the circle. Further, when the flow path is closed by a flowing unit, X is displayed in the circle. 
     First, a procedure in which the cleaning liquid is introduced into the first ink container  21  from a state shown in  FIG. 2  will be described. This procedure is performed when the control unit transfers the first ink stored in the first ink container  21  to the second ink container  22  through the common flow path system  42  by controlling the first valve  61 , the second valve  62 , the third valve  63 , and the first pomp  71 , and transfers the cleaning liquid stored in the cleaning liquid container  32  to the first ink container  21  through the cleaning liquid flow path  44  and the common flow path system  42  by controlling the first valve  61 , the second valve  62 , the third valve  63 , and the second pomp  72 . 
     Specifically, as shown in  FIG. 3 , the first ink container  21  and the common flow path system  42  are communicated with each other by the first valve  61 , and the second ink container  22  and the common flow path system  42  are communicated with each other by the second valve  62 . Thereby, a passage that communicates the first ink container  21 , the common flow path system  42 , and the second ink container  22  with each other is formed. Then, the first ink is transferred to the second ink container  22  by driving the first pomp  71 . 
     Then, as shown in  FIG. 4 , the second valve  62  is closed, and the cleaning liquid flow path  44  and the common flow path system  42  are communicated with each other by the third valve  63 . Thereby, a passage that communicates the cleaning liquid container  32 , the cleaning liquid flow path  44 , the common flow path system  42 , and the first ink container  21  with each other is formed. Then, the cleaning liquid is transferred to the first ink container  21  by driving the second pomp  72 . In the case of this example, the cleaning liquid may be transferred by driving the first pomp  71  instead of the second pomp  72  in a direction opposite to the transfer direction of the first ink. 
     In this way, the cleaning liquid is introduced into the first ink container  21 , and the first ink container  21  can be cleaned. Further, the amount of the first ink to be discarded can be reduced by transferring the first ink to the second ink container  22 . 
     Next, the cleaning liquid in the first ink container  21  is transferred to the first head  11  through the first flow path system  51  by controlling the fifth valve  65 . More specifically, as shown in  FIG. 4 , the fifth valve  65  is opened, the first head  11  is sealed by the suction cap  95 , the first flow path system  51  is coupled to the suction flow path  48 , and the sixth pomp  96  is driven, so that the cleaning liquid that has cleaned the first ink container  21  is transferred to the waste liquid container  34 . Thereby, the cleaning liquid stored in the first ink container  21  passes through the first flow path system  51 , so that the cleaning liquid cleans the first flow path system  51 . The sixth pomp  96  may be driven after the cleaning liquid is sufficiently stored in the first ink container  21  or may be driven at the same time when the cleaning liquid is introduced into the first ink container  21 . 
     On the other hand, as shown in  FIG. 5 , the first ink in the first flow path system  51  on the first ink container  21  side of the first auxiliary container  81  may be collected to the first ink container  21  by opening the fifth valve  65  and driving the fifth pomp  75  before transferring the first ink from the first ink container  21  to the second ink container  22 . By doing so, it is possible to collect the first ink stored in the first auxiliary container  81  and further reduce the amount of the first ink to be discarded. 
     Further, as shown in  FIG. 6 , the first ink in the first auxiliary container  81  and the first head  11  may be transferred to the waste liquid container  34  by closing the fifth valve  65 , capping the first head  11  with the suction cap  95 , and driving the sixth pomp  96  before transferring the cleaning liquid from the first ink container  21  to the waste liquid container  34 . By doing so, it is possible to discard in advance the first ink between the first auxiliary container  81  and the first head  11 . Therefore, it is possible to further improve cleaning efficiency when the cleaning liquid passes through the first flow path system  51 . 
     Further, as shown in  FIG. 7 , when the cleaning liquid stored in the cleaning liquid container  32  is transferred to the first ink container  21  through the cleaning liquid flow path  44  and the common flow path system  42 , a liquid flow rate of the first flow path system  51  may be reduced by controlling the fifth valve  65 . In this case, the fifth valve  65  may be closed. By doing so, a larger amount of the cleaning liquid can be stored in the first ink container  21 . Thereby, it is possible to clean the first ink container  21  up to its upper part, so that it is possible to more efficiently clean the first ink container  21 . 
     The cleaning liquid stored in the first ink container  21  may be transferred to the waste liquid container  34  through a passage other than the first flow path system  51 .  FIG. 8  shows an example in which the cleaning liquid transferred to the first ink container  21  is transferred to the waste liquid container  34  through the waste liquid flow path system  46  by controlling the first valve  61 , the fourth valve  64 , and the third pomp  73 . As shown in  FIG. 8 , the cleaning liquid in the first ink container  21  can be transferred to the waste liquid container  34  through the waste liquid flow path system  46  by causing the first valve  61  to communicate the first ink container  21  and the waste liquid flow path system  46  with each other and driving the third pomp  73  provided on the waste liquid flow path system  46 . 
     By doing so, the cleaning liquid in the first ink container  21  can be transferred to the waste liquid container  34  without through the first flow path system  51 . Therefore, for example, when a foreign object occurs in the first ink container  21 , it is possible to prevent the foreign object from passing through the first head  11 . Specifically, in the first head  11 , there are flow paths with small flow path diameter such as nozzles, flow path resistance portions, and filters, so that if a foreign object enters into the first head  11 , there is a risk of occurrence of clogging. On the other hand, in the configuration described above, the cleaning liquid in the first ink container  21  is transferred to the waste liquid container  34  without through the first flow path system  51 . Therefore, it is possible to suppress clogging of the first head  11  even when there is a foreign object. 
     When the cleaning liquid in the first ink container  21  is transferred to the waste liquid container  34  through the waste liquid flow path system  46 , the cleaning liquid may be transferred to the waste liquid container  34  through two passages, which are the waste liquid flow path system  46  and the first flow path system  51 , by opening the fifth valve  65 . Thereby, it is possible to increase a transfer speed of the cleaning liquid from the first ink container  21  to the waste liquid container  34 , so that cleaning time can be shortened. 
     As described above, the common flow path system  42  let both the first ink and the cleaning liquid to pass through. Therefore, it is possible to more smoothly perform the next above operation by cleaning the common flow path system  42  with the cleaning liquid. Specifically, the cleaning liquid stored in the cleaning liquid container  32  may be transferred to the waste liquid container  34  through the cleaning liquid flow path  44 , the common flow path system  42 , and the waste liquid flow path system  46  by controlling the first valve  61 , the second valve  62 , the third valve  63 , the fourth valve  64 , and the fourth pomp  74 . More specifically, as shown in  FIG. 9 , the common flow path system  42  and the waste liquid flow path system  46  are communicated with each other by the first valve  61  and the second valve  62 , and the cleaning liquid flow path  44  and the common flow path system  42  are communicated with each other by the third valve  63 . When the fourth pomp  74  is driven, the cleaning liquid can be transferred to the waste liquid container  34  through the cleaning liquid flow path  44 , the common flow path system  42 , and the waste liquid flow path system  46 . 
     In the example of  FIG. 9 , the first valve  61  and the second valve  62  double as the fourth valve  64 . These valves may be provided separately from each other. The fourth pomp  74  doubles as the second pomp  72  and the third pomp  73 . These pomps may be provided separately from each other. Regarding these fourth pomps  74 , it is enough to provide at least one fourth pomp  74 . Further, in the example of  FIG. 9 , a region of the common flow path system  42  other than a region of the common flow path system  42  through which the first ink passes is also cleaned by the above operation. By doing so, it is possible to easily maintain a clean state of the entire common flow path system  42 . 
     In the droplet discharge apparatus  100 , the second ink container  22  is provided with the second sensor  92  that detects the amount of liquid inside the second ink container  22 . When the first ink is transferred from the first ink container  21  to the second ink container  22 , if the second sensor  92  detects that the amount of liquid in the second ink container  22  exceeds a predetermined amount, the second ink in the second ink container  22  may be transferred to the second auxiliary container  82  by opening the sixth valve  66 . By doing so, a larger amount of the first ink can be stored in the second ink container  22 , so that it is possible to further suppress waste of ink. 
     In the droplet discharge apparatus  100 , the first ink container  21  is provided with the first sensor  91  that detects the amount of liquid inside the first ink container  21 . When the total amount of the amount of liquid in the first ink container  21  detected by the first sensor  91  and the amount of liquid in the second ink container  22  detected by the second sensor  92  exceeds the amount of liquid that can be stored in the second ink container  22 , the second ink in the second ink container  22  may be transferred to the second auxiliary container  82  by opening the sixth valve  66 . 
     In the droplet discharge apparatus  100 , the first auxiliary container  81  is provided with a third sensor not shown in the figures that detects the amount of liquid inside the first auxiliary container  81 . When the total amount of the amount of liquid in the first auxiliary container  81  detected by the third sensor and the amount of liquid in the first ink container  21  detected by the first sensor  91  exceeds the amount of liquid that can be stored in the first ink container  21 , The droplet discharge apparatus  100  may transfer the first ink from the first ink container  21  to the second ink container  22  before collecting the first ink located in the first flow path system  51  on the first ink container  21  side of the first auxiliary container  81  into the first ink container  21 . 
     When the first sensor detects that the amount of liquid in the first ink container  21  exceeds a predetermined amount while the droplet discharge apparatus  100  collects the first ink located in the first flow path system  51  on the first ink container  21  side of the first auxiliary container  81  into the first ink container  21 , the droplet discharge apparatus  100  may start transferring the first ink from the first ink container  21  to the second ink container  22 . At a time point when the transfer of the first ink from the first ink container  21  to the second ink container  22  is completed, the first ink located in the first flow path system  51  on the first ink container  21  side of the first auxiliary container  81  may be collected into the first ink container  21  again. Regarding a method of determining whether or not ink remains in the first auxiliary container  81 , the third sensor may detect the amount of liquid in the first auxiliary container  81 , or it may be determined that ink remains in the first auxiliary container  81  when the first sensor detects that the amount of liquid in the first ink container  21  is increasing. 
     Further, when the amount of liquid in the first ink container  21  detected by the first sensor  91  is smaller than the amount of liquid in the second ink container  22  detected by the second sensor  92 , the first ink stored in the first ink container  21  may be transferred to the second ink container  22  through the common flow path system  42 . That is, when the first ink and the second ink are the same ink and another ink is filled into either one of the first ink container  21  and the second ink container  22 , any one of the first ink container  21  and the second ink container  22  can be cleaned and emptied by the procedure described above. However, it is preferable to clean and empty the ink container containing less ink between the first ink container  21  and the second ink container  22 . By doing so, the amount of transfer of ink between the first ink container  21  and the second ink container  22  can be reduced, so that, for example, it is possible to reduce time to perform the above procedure. 
     As described above, the droplet discharge apparatus  100  of the present embodiment can suppress waste of ink and easily form an acceptance state for replacing ink. Therefore, when a user replaces ink, it is easy to prepare a cleaned ink container, and desired recording can be performed when the user introduces a desired ink into the ink container. 
     While a replacing method of ink in the droplet discharge apparatus  100  is described in the present embodiment, an ink system including the first head  11 , the second head  12 , the first ink container  21 , the second ink container  22 , the common flow path system  42 , the first flow path system  51 , and the second flow path system  52  may be attached to and detached from the droplet discharge apparatus. In this case, a cleaning apparatus including the cleaning liquid container  32 , the waste liquid container  34 , the cleaning liquid flow path  44 , the waste liquid flow path system  46 , the suction flow path  48 , and the suction caps  95  may be attached to and detached from the droplet discharge apparatus. The cleaning apparatus is a different body from the droplet discharge apparatus. The ink system is attached to the cleaning apparatus and performs replacement of ink. By doing so, another ink system can be attached to the droplet discharge apparatus, so that it is not necessary to stop the droplet discharge apparatus for an ink replacement operation. 
     The present disclosure is not limited to the embodiment described above, but can be variously modified. For example, the present disclosure includes substantially the same configuration as that described in the embodiment, such as, for example, a configuration having the same functions, methods, and results, or a configuration having the same object and effects. Further, the present disclosure includes a configuration in which non-essential portions of the configuration described in the embodiment are replaced. Further, the present disclosure includes a configuration that achieves the same operational effects or can achieve the same object as those of the configuration described in the embodiment. Further, the present disclosure includes a configuration in which a known technique is added to the configuration described in the embodiment.