Liquid dispensing device and control method for liquid dispensing device

Abstract

This invention provides a liquid dispensing device and a control method for the liquid dispensing device that can reduce liquid waste by decreasing the amount of liquid remaining when the liquid container is replaced. [Solution] The liquid dispensing device comprises a liquid dispensing unit, a liquid storage unit capable of storing the liquid to be supplied to the liquid dispensing unit, a mounting unit to which a liquid container for containing liquid is attached, a transfer unit for transferring liquid from the liquid container to the liquid storage unit via the mounting unit, and a control unit. When the first remaining amount L1, which is the amount of liquid in the liquid container, becomes less than or equal to a first threshold R1, the control unit executes a transfer mode to transfer the liquid in the liquid container to the liquid storage unit until the second remaining amount L2, which is the amount of liquid in the liquid storage unit, becomes less than or equal to a second threshold R2 (S11, S14~S19). After executing the transfer mode and before the liquid container is replaced, when the second remaining amount L2 becomes less than or equal to a third threshold R3, which is a value smaller than the second threshold R2, the control unit executes the transfer mode again (S22, S14~S19).

Description

Technical Field

[0005] , ,

[0001] The present invention relates to a liquid ejection device including a liquid ejection unit that ejects a liquid, and a control method for the liquid ejection device.

Background Art

[0002] For example, Patent Document 1 describes an inkjet printing device as an example of a liquid ejection device that ejects ink, which is an example of a liquid, from an inkjet head (an example of a liquid ejection unit) to print on a medium. The inkjet printing device includes a printing unit having an inkjet head.

[0003] The printing unit includes a sub-tank (an example of a liquid storage unit) that receives the supply of ink from an ink cartridge (an example of a liquid container). In the technology of Patent Document 1, when the ink amount in the ink cartridge reaches near the end, a new ink cartridge is ordered. The printing unit supplies the ink in the ink cartridge to the sub-tank up to the position of the liquid level sensor immediately after the order flag is turned on. Therefore, the user can replace the ink cartridge with a new one when the remaining ink amount is considerably less than near the end or in an empty state.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, when a user replaces an ink cartridge after near-end printing, some ink may remain in the cartridge. For example, if the amount of ink that can be supplied to the sub-tank up to the liquid level sensor level is less than the amount of ink remaining at near-end printing, some ink will remain in the cartridge even after supplying ink up to the liquid level sensor level. If a user does not replace the ink cartridge for a while after near-end printing, the ink in the sub-tank will be consumed by printing and cleaning, so even though the liquid level in the sub-tank has enough capacity to supply ink up to the liquid level sensor level, there is a risk that the ink cartridge will be replaced while there is still ink remaining. Thus, even though there is enough capacity to transfer liquid to the liquid reservoir, there is a risk that the liquid reservoir will be replaced while there is still liquid remaining, and there is room for improvement. [Means for solving the problem]

[0006] A liquid dispensing device that solves the above problems comprises a liquid dispensing unit capable of dispensing liquid, a liquid storage unit capable of storing liquid supplied to the liquid dispensing unit, a mounting unit to which a liquid container for containing liquid is attached, a transfer unit for transferring liquid from the liquid container to the liquid storage unit via the mounting unit, and a control unit. The control unit executes a transfer mode when the first remaining amount, which is the amount of liquid in the liquid container, falls below a first threshold, and transfers the liquid in the liquid storage unit to the liquid storage unit until the second remaining amount, which is the amount of liquid in the liquid storage unit, falls below a second threshold. After the transfer mode has been executed but before the liquid container is replaced, if the second remaining amount falls below a third threshold, which is a value smaller than the second threshold, the transfer mode is executed again.

[0007] A control method for a liquid dispensing device that solves the above problems comprises a liquid dispensing unit capable of dispensing liquid, a liquid storage unit capable of storing liquid supplied to the liquid dispensing unit, a mounting unit to which a liquid container for storing liquid is attached, and a transfer unit for transferring liquid from the liquid container to the liquid storage unit via the mounting unit, wherein when the first remaining amount, which is the amount of liquid in the liquid container, falls below a first threshold, a transfer mode is executed to transfer the liquid in the liquid container to the liquid storage unit until the second remaining amount, which is the amount of liquid in the liquid storage unit, falls below a second threshold, and after the transfer mode has been executed but before the liquid container is replaced, if the second remaining amount falls below a third threshold, which is a value smaller than the second threshold, the transfer mode is executed again. [Brief explanation of the drawing]

[0008] [Figure 1] Figure 1 is a perspective view showing a liquid dispensing device in the first embodiment. [Figure 2] Figure 2 is a schematic side cross-sectional view of the liquid supply unit and liquid discharge section. [Figure 3] Figure 3 is a schematic side cross-sectional view showing the configuration of the connection between the liquid container and the mounting part. [Figure 4] Figure 4 is a schematic side cross-sectional view illustrating the principle by which liquid is supplied from the liquid container to the first storage chamber. [Figure 5] Figure 5 is a schematic side cross-sectional view showing a configuration in which a physical sensor detects when the first remaining amount in the liquid container is below a first threshold. [Figure 6] Figure 6 is a schematic side view illustrating the principle of a physical sensor. [Figure 7] Figure 7 is a block diagram showing the electrical configuration of the liquid dispensing device. [Figure 8] Figure 8 is a block diagram showing the functional configuration of the control unit. [Figure 9] Figure 9 is a schematic diagram showing the liquid volume display setting screen. [Figure 10] Figure 10 is a schematic diagram showing a notification screen prompting the replacement of a liquid container. [Figure 11]Figure 11 is a schematic diagram showing the liquid volume information display screen that appears after the transfer mode is executed. [Figure 12] Figure 12 is a flowchart showing the transport mode routine. [Figure 13] Figure 13 is a schematic side cross-sectional view showing the liquid supply unit and liquid discharge section at the start of the transfer mode. [Figure 14] Figure 14 is a schematic side cross-sectional view showing the second storage chamber under reduced pressure in the transfer mode. [Figure 15] Figure 15 is a schematic side cross-sectional view showing how liquid is supplied from the liquid container to the first storage chamber in the transfer mode. [Figure 16] Figure 16 is a schematic side cross-sectional view showing the second storage chamber open to the atmosphere in the transfer mode. [Figure 17] Figure 17 is a schematic side cross-sectional view showing the process of supplying liquid from the liquid container to the first storage chamber after depressurization of the second storage chamber in the second transfer mode. [Figure 18] Figure 18 is a schematic side cross-sectional view showing the second storage chamber open to the atmosphere in the second transfer mode. [Figure 19] Figure 19 is a flowchart showing the transport mode routine in the second embodiment. [Figure 20] Figure 20 is a schematic side cross-sectional view showing the two storage chambers under pressurization in the transfer mode. [Figure 21] Figure 21 is a schematic side cross-sectional view showing how liquid is supplied from the liquid container to the first storage chamber in the transfer mode. [Figure 22] Figure 22 is a schematic side cross-sectional view showing the state in which the two storage chambers are open to the atmosphere during the transfer mode. [Figure 23] Figure 23 is a schematic side cross-sectional view showing a configuration in the third embodiment in which a physical sensor detects when the first remaining amount in the liquid container is below an end threshold. [Figure 24] Figure 24 is a schematic side cross-sectional view of the liquid supply unit in the modified example when the liquid container is at the near end and the transfer mode has started. [Figure 25] FIG. 25 is a schematic cross-sectional view showing the liquid supply unit after the transfer mode is executed in the liquid supply unit shown in FIG. 24. [Figure 26] FIG. 26 is a schematic cross-sectional view showing a liquid supply unit and a liquid discharge unit different from those shown in FIGS. 24 and 25. [Figure 27] FIG. 27 is a schematic cross-sectional view showing an example of a variable-capacity liquid storage unit provided in a flow path, which is a modification different from that shown in FIG. 26. [Figure 28] FIG. 28 is a schematic cross-sectional view showing a state in which liquid is stored in the variable-capacity liquid storage unit shown in FIG. 26.

Embodiments for Carrying Out the Invention

[0009] [First Embodiment] Hereinafter, a first embodiment of a liquid discharge device will be described with reference to the drawings. The liquid discharge device is, for example, an inkjet printer that discharges and prints ink, which is an example of a liquid, onto a medium such as paper.

[0010] In FIG. 1, it is assumed that the liquid discharge device 11 is placed on a horizontal plane, and the direction of gravity is indicated by the Z-axis, and the directions along the horizontal plane are indicated by the X-axis and the Y-axis. The X-axis, Y-axis, and Z-axis are perpendicular to each other. The X-axis indicates the depth direction of the liquid discharge device 11, and the Y-axis indicates the width direction of the liquid discharge device 11. Since the direction parallel to the X-axis is also the width direction of the medium M, it may be referred to as the width direction X.

[0011] [Overall Configuration of Liquid Discharge Device 11] As shown in FIG. 1, the liquid discharge device 11 is, for example, a multifunction device. The liquid discharge device 11 includes a device main body 12 having a rectangular parallelepiped shape. The device main body 12 constitutes an inkjet printer. The liquid discharge device 11 includes an image reading unit 13 above the device main body 12.

[0012] The image reading unit 13 comprises a reading unit 13A that reads the original document D and an automatic document feeding unit 13B that feeds the original document D. The automatic document feeding unit 13B feeds the original document D placed on the document tray 13C to the reading unit 13A and also discharges the original document D, which has been read by the reading unit 13A, to the output tray 13D. The image reading unit 13 also has a flatbed type reading function in which the reading unit 13A reads the original document D set on the document table, which is exposed when the automatic document feeding unit 13B, which also serves as the document table cover, is opened.

[0013] The liquid dispensing device 11 may include a media storage section 14 capable of accommodating multiple media M. The media storage section 14 is, for example, a cassette. The media storage section 14 may be provided in one or more stages (for example, four stages in Figure 1). The media storage section 14 is inserted into the lower part of the device body 12 in a manner that allows it to be attached and detached by sliding in the X direction. Multiple media storage sections 14 can accommodate, for example, media M of different sizes or types. In addition to the media storage section 14, or instead of the media storage section 14, the liquid dispensing device 11 may also include a media placement section 15, such as a paper feed tray, on which media M can be placed, as a media supply section.

[0014] The liquid dispensing device 11 includes a stacker 16 for receiving the printed media M. The liquid dispensing device 11 has a recess 12A between the device body 12 and the image reading unit 13. The stacker 16 consists of the recess 12A and an output tray 16A attached to the bottom of the recess 12A. The printed media M discharged from the device body 12 is stacked on the output tray 16A. The output tray 16A is inclined at a predetermined angle such that the downstream side in the output direction from which the printed media M is discharged is higher than the upstream side.

[0015] The liquid dispensing device 11 includes a display unit 17. The display unit 17 may be located at the front of the device body 12. The display unit 17 may be, for example, a touch panel. In this case, the touch panel function of the display unit 17 may constitute the operation unit 18. The user can give instructions to the liquid dispensing device 11 by operating the operation unit 18. The operation unit 18 is operated, for example, when selecting at least one of the options on the setting screen displayed on the display unit 17. The display unit 17 also functions as a notification unit that notifies the user of notification information. In this embodiment, when the remaining amount in the liquid container 30 (described later) falls below the near end or ink end, the liquid dispensing device 11 causes the display unit 17, which functions as a notification unit, to notify, for example, information prompting the replacement of the liquid container 30.

[0016] Furthermore, the liquid dispensing device 11 is equipped with a power switch 18A that is operated to turn the power ON / OFF. The operation unit 18 may be configured with one or more operation buttons consisting of mechanical switches, separate from or in place of the touch panel of the display unit 17.

[0017] As shown in Figure 1, the liquid dispensing device 11 includes a liquid dispensing unit 20 capable of dispensing liquid. The liquid dispensing unit 20 is housed within the device body 12. The liquid dispensing unit 20 is positioned in the device body 12 opposite the transport path (not shown) through which the medium M is transported. The liquid dispensing unit 20 includes a dispensing head 21 capable of dispensing liquid. The liquid dispensing unit 20 is positioned in a predetermined orientation with the dispensing head 21 facing the transport path. The medium M is transported along the transport path while maintaining a state in which its width direction is parallel to the X-axis. Therefore, the dispensing head 21 is positioned in an orientation parallel to the X-axis. The liquid dispensing unit 20 prints an image or characters on the medium M by having the dispensing head 21 dispense ink, which is an example of a liquid, onto the medium M being transported along the transport path.

[0018] The liquid dispensing device 11 includes a liquid supply unit 22 that supplies liquid (e.g., ink) to the liquid dispensing unit 20. The liquid supply unit 22 includes one or more (for example, four in Figure 1) liquid containers 30 installed inside the device body 12. The liquid containers 30 are, for example, ink cartridges. The multiple liquid containers 30 each contain ink of multiple colors, for example, black (K), cyan (C), magenta (M), and yellow (Y). The device body 12 may have a cover 19 at its front. The liquid containers 30 are housed behind the cover 19. The cover 19 is opened and closed when the user replaces the liquid containers 30, etc. For example, when the remaining amount of liquid in the liquid containers 30 is near-end, a notification screen indicating the near-end is displayed on the display unit 17. The notification screen provides information prompting the user to replace the liquid container 30 by specifying a color. The user can perform a replacement operation by opening the cover 19, for example, by replacing the liquid container 30 of a specified color with a new one. The cover 19 has a transparent window 19A that allows the liquid container 30 inside to be viewed from the outside.

[0019] <Configuration of liquid supply unit 22 and liquid discharge unit 20> Next, the configuration of the liquid supply unit 22 and the liquid discharge unit 20 will be described with reference to Figure 2. Although a liquid supply unit 22 is provided for each liquid container 30, the basic configuration is almost the same, so Figure 2 shows one liquid supply unit 22 containing one liquid container 30.

[0020] As shown in Figure 2, the liquid dispensing device 11 comprises a liquid storage unit 40, a mounting unit 50, a transfer unit 60, and a control unit 100. Of these, the liquid storage unit 40, the mounting unit 50, and the transfer unit 60 constitute the liquid supply unit 22.

[0021] The liquid container 30 comprises a container body 31 (hereinafter also simply referred to as "body 31") and a supply unit 32. The body 31 has a volume capable of holding a predetermined amount of liquid (e.g., ink). The body 31, for example, has a roughly rectangular parallelepiped shape that is elongated in one direction. The supply unit 32 is provided at, for example, one end of the liquid container 30. In the example shown in Figure 2, the supply unit 32 extends from one end of the body 31. Note that the supply unit 32 may not protrude from the body 31.

[0022] The liquid storage section 40 is configured to store the liquid to be supplied to the liquid discharge section 20. The liquid storage section 40 and the liquid discharge section 20 are connected via a supply channel 46. The liquid in the liquid storage section 40 is supplied to the liquid discharge section 20 via the supply channel 46. Details of the liquid storage section 40 and the supply channel 46 will be described later.

[0023] The transfer unit 60 transfers liquid from the liquid container 30 to the liquid storage unit 40 via the mounting unit 50. In this embodiment, the transfer unit 60 transfers liquid from the liquid container 30 to the liquid storage unit 40 by controlling the air pressure relative to the liquid surface in the liquid storage unit 40. Details of the transfer unit 60 will be described later.

[0024] The configuration of the liquid storage unit 40, mounting unit 50, liquid discharge unit 20, and transfer unit 60 will be described below with reference to Figure 2. <Configuration of mounting section 50> First, the configuration of the mounting section 50 will be described with reference to Figure 2. As shown in Figure 2, the mounting section 50 is fitted with a liquid container 30 that holds liquid. The mounting section 50 connects the fitted liquid container 30 and the liquid storage section 40 in a manner that allows for the supply of liquid. The mounting section 50 has a supply portion 51 that extends upward from, for example, a part of the upper part of the liquid storage section 40.

[0025] The mounting section 50 may have a case 52 in which the liquid container 30 is detachably housed. The case 52 has a guide function for guiding the liquid container 30. The guide function guides the liquid container 30 to the mounting position shown in Figure 2 within the case 52. After being guided horizontally inward along the case 52, the liquid container 30 tilts slightly clockwise in Figure 2, so that it is mounted in the mounting position shown in Figure 2 with its supply section 32 connected to the supplyed section 51 of the mounting section 50.

[0026] The liquid container 30 may have a memory element 33 at its front. The case 52 may have a connection terminal 53 at a position corresponding to the memory element 33 on its inner wall at the back. When the liquid container 30 is in the mounting position shown in Figure 2, the terminals of the memory element 33 are electrically connected to the connection terminal 53 provided on the inner wall of the case 52. The memory element 33 stores ink-related information concerning the liquid container 30. The ink-related information includes remaining liquid amount data for each liquid container 30. In addition to the remaining liquid amount data, the ink-related information includes various information such as color information and part number information.

[0027] When the liquid container 30 is in the mounted state shown in Figure 2, the control unit 100 can access the memory element 33 to read and write remaining data to the memory element 33. Details of the configuration in which the liquid container 30 and the mounting unit 50 are mounted will be described later.

[0028] <Configuration of the liquid storage section 40> As shown in Figure 2, the liquid storage section 40 includes a first storage chamber 71, an outlet channel 41, a second storage chamber 76, a one-way valve 42, and a liquid supply section 56.

[0029] The first storage chamber 71 stores liquid. The first storage chamber 71 stores liquid supplied from the liquid container 30 via the attachment part 50. The first storage chamber 71 is, for example, a sub-tank when the liquid container 30 is the main tank. The first storage chamber 71 is partitioned inside a box-shaped first housing 72 having a predetermined shape.

[0030] The second storage chamber 76 stores liquid. The second storage chamber 76 stores liquid supplied from the first storage chamber 71. The second storage chamber 76 is a reservoir tank, for example, that temporarily stores liquid supplied from the first storage chamber 71, which is a sub-tank. The second storage chamber 76 is partitioned and formed inside a box-shaped second housing 77 having a predetermined shape.

[0031] The outlet channel 41 is connected at one end to the first storage chamber 71 and discharges the liquid from the first storage chamber 71. The second storage chamber 76 is connected at the other end of the outlet channel 41 and stores the liquid supplied from the first storage chamber 71.

[0032] The one-way valve 42 is installed in the outlet channel 41. The one-way valve 42 restricts the direction in which the liquid flows through the outlet channel 41 to one direction, from the first storage chamber 71 to the second storage chamber 76. The first storage chamber 71 has an air chamber 73 above the liquid level P2 of the stored liquid. A moisture-permeable membrane 74 is provided at the top of the first housing 72, separating the air chamber 73 from the outside atmosphere. The first storage chamber 71, the first housing 72, and the moisture-permeable membrane 74 constitute, for example, the first storage section 70. The moisture-permeable membrane 74 is a membrane that does not permeate liquid but does permeate air.

[0033] The second storage chamber 76 has an air chamber 78 above the liquid level P3 of the stored liquid. A moisture-permeable membrane 79 is provided at the top of the second housing 77, separating the air chamber 78 from the outside atmosphere. The second storage chamber 76, the second housing 77, and the moisture-permeable membrane 79 constitute, for example, the second storage section 75. The moisture-permeable membrane 79 is a membrane that does not permeate liquid but does permeate air. The liquid storage section 40 may also be configured as a single housing in which the first housing 72 and the second housing 77 are integrally formed, and a partition wall that separates the inside of the single housing into two storage chambers 71 and 76.

[0034] <Regarding the configuration of the liquid supply unit 56> As shown in Figure 2, the liquid supply unit 22 includes a liquid supply unit 56 that supplies liquid from the liquid container 30 to the first storage chamber 71 via the mounting unit 50 when the liquid level P2 in the liquid storage unit 40 falls below the reference liquid level SP. In this embodiment, the liquid supply unit 56 is composed of, for example, a gas-liquid exchange unit 57. When the liquid level P2 falls below the reference liquid level SP, the gas-liquid exchange unit 57 performs gas-liquid exchange in which air from the liquid storage unit 40 side is sent to the mounting unit 50 side, and liquid of approximately the same volume as the air is sent from the mounting unit 50 side to the liquid storage unit 40 side. When the liquid level P2 falls below the reference liquid level SP to which liquid should be supplied, the gas-liquid exchange unit 57 supplies liquid from the mounting unit 50 to the liquid storage unit 40 through gas-liquid exchange. As a result, the liquid level P2 in the liquid storage unit 40 is generally maintained at or near the reference liquid level SP. The detailed configuration of the gas-liquid exchange unit 57, which functions as a liquid supply unit 56, will be described later.

[0035] <Configuration for detecting the first remaining charge L1 and the second remaining charge L2> As shown in Figure 2, the liquid supply unit 22 includes detection units 90 and 123 (see Figures 5 to 8) that detect when the first remaining amount L1, which is the amount of liquid in the liquid container 30, falls below a first threshold R1. The detection unit 90 may be a physical sensor (see Figures 5 and 6) capable of detecting when the first physical remaining amount falls below the first threshold R1. Alternatively, the detection unit 90 may be a detection unit 123 (see Figure 8) consisting of a soft sensor that detects when the first estimated remaining amount, which is an estimated value of the first remaining amount, falls below the first threshold R1. Here, the first threshold R1 is, for example, a threshold indicating the near-end remaining amount. In other words, the detection unit 90 is configured to detect when the first remaining amount L1 has reached the near-end. However, the first threshold R1 may be a threshold indicating a remaining amount other than the near-end. The first threshold R1 may be greater than or less than the near-end remaining amount. The detailed configuration of the detection unit 90 will be described later.

[0036] As shown in Figure 2, the liquid supply unit 22 may include a detection unit 43 that physically detects when the second remaining amount L2 reaches the second threshold R2. The detection unit 43 is not limited to a physical sensor, but may also be a detection unit 126 (see Figure 8) consisting of a soft sensor that detects when the second estimated remaining amount, which is an estimated value of the second remaining amount L2, reaches the second threshold R2. Here, the second threshold R2 is, for example, a threshold that defines the upper limit of the second remaining amount L2. In other words, the detection unit 43 is configured to detect when the second remaining amount L2 reaches the upper limit. The upper limit is, for example, a threshold for error detection where the liquid level in the liquid storage unit 40 is abnormal. The upper limit is, for example, a threshold set to detect overflow of the liquid storage unit 40. The detection unit 43 also functions as an error detection unit that detects when the second remaining amount L2 reaches the second threshold R2 as an error. In other words, the detection unit 43 also functions as an error sensor. In this embodiment, the detection unit 43 also functions as an overflow sensor that detects an upper limit as an overflow. Furthermore, the second threshold R2 may be the upper limit of the second remaining amount L2, which prevents liquid leakage from the nozzle 21N due to an excessive head difference between the liquid storage unit 40 and the liquid discharge unit 20. In this case, the detection unit 43 also functions as an error detection unit (error sensor) that detects when an excessive head difference occurs.

[0037] The second threshold R2 is not limited to the upper limit; it may also be a value corresponding to the remaining amount between the reference liquid level SP and the upper limit. If the second remaining amount L2 exceeds the upper limit, excessive liquid pressure due to the difference in water head may cause leakage from the nozzle 21N. For this reason, an upper limit is set. The upper limit is set to a relatively low value, including a safety margin. Therefore, there is no problem even if the liquid exceeds the upper limit by an allowable amount. The detailed configuration of the detection unit 126, which consists of a soft sensor, will be described later.

[0038] Furthermore, the liquid supply unit 22 may include a detection unit 44 that detects when the second remaining amount L2 in the liquid storage unit 40 reaches a lower limit. Hereinafter, a detection unit 43 that detects when the second remaining amount L2 reaches a second threshold R2 will be referred to as the first detection unit 43. A detection unit 44 that detects when the second remaining amount L2 reaches a lower limit will be referred to as the second detection unit 44.

[0039] As shown in Figure 2, in this embodiment, each detection unit 43, 44 is composed of an electrode-type sensor 45 provided in the first storage unit 70. The electrode-type sensor 45 includes an upper limit electrode 45A, a lower limit electrode 45B, and a reference electrode 45C. The length of each electrode 45A to 45C extending downward is progressively longer in the order of upper limit electrode 45A, lower limit electrode 45B, and reference electrode 45C. The height of the lower end of the upper limit electrode 45A is above the reference liquid level SP. The height of the lower end of the lower limit electrode 45B is below the reference liquid level SP. The lower end of the reference electrode 45C is below the lower end of the lower limit electrode 45B and above the inner bottom surface of the first housing 72.

[0040] The first detection unit 43 is composed of an upper limit electrode 45A and a reference electrode 45C. The potential difference when the liquid level P2 of the second remaining amount L2 is at a height above the lower end of the upper limit electrode 45A is smaller than the potential difference when the liquid level P2 is at a height below the lower end of the upper limit electrode 45A. Based on the potential difference between the upper limit electrode 45A and the reference electrode 45C, the first detection unit 43 detects that the second remaining amount L2 has reached its upper limit.

[0041] The second detection unit 44 is composed of a lower limit electrode 45B and a reference electrode 45C. The potential difference when the liquid level P2 of the second remaining amount L2 is at a height above the lower end of the lower limit electrode 45B is smaller than the potential difference when the liquid level P2 is at a height below the lower end of the lower limit electrode 45B. The second detection unit 44 detects that the second remaining amount L2 has reached its lower limit based on the potential difference between the lower limit electrode 45B and the reference electrode 45C.

[0042] Furthermore, the liquid dispensing device 11 may also include a detection unit 123 (see Figure 8) that detects when the first remaining amount L1 of the liquid container 30 has reached its limit. Hereinafter, the detection unit 90 that detects when the first remaining amount L1 falls below the first threshold R1 will also be referred to as the first detection unit 90. The detection unit 123 that detects when the first remaining amount L1 has reached its limit will also be referred to as the second detection unit 123. The second detection unit 123 in this embodiment is a soft sensor and detects when the liquid container 30 has reached its limit by estimating that the liquid container 30 has reached its limit based on the detection result of the first detection unit 43. When the liquid container 30 reaches its limit and liquid is no longer supplied to the first storage chamber 71, the second remaining amount L2 will eventually reach its lower limit. The second detection unit 44 may detect the end of the liquid container 30 when it detects the lower limit of the second remaining amount L2.

[0043] Here, the first remaining amount L1 of the liquid container 30 at the end is a value greater than or equal to zero and less than the first threshold R1. The first remaining amount L1 at the end may be zero or a value greater than zero. Here, the state in which the first remaining amount L1 of the liquid container 30 is less than or equal to the end threshold is defined as the liquid container 30 being at the end. The end threshold is a value greater than or equal to zero and less than the first threshold R1. If the first threshold R1 is near the end, the end threshold is a value greater than or equal to zero and less than the near-end threshold. The end threshold is zero or the amount that can no longer be printed. Near-end is notified to the user so that they can prepare a new liquid container 30 that can be replaced before the end.

[0044] <Regarding the configuration of supply channels 46, etc.> As shown in Figure 2, the liquid dispensing device 11 of this embodiment includes a supply channel 46 for supplying liquid from the liquid storage section 40 to the liquid dispensing section 20, and a recovery channel 47 for recovering liquid from the liquid dispensing section 20 to the liquid storage section 40. In other words, the liquid supply unit 22 includes a supply channel 46 and a recovery channel 47 as channels connecting the liquid storage section 40 and the liquid dispensing section 20.

[0045] One end of the supply channel 46 is connected to the second storage chamber 76, and the other end of the supply channel 46 is connected to the liquid discharge section 20. One end of the recovery channel 47 is connected to the first storage chamber 71, and the other end of the recovery channel 47 is connected to the liquid discharge section 20. The supply channel 46 is provided with a first channel valve 48. The recovery channel 47 is provided with a second channel valve 49.

[0046] During printing, the first storage chamber 71 and the second storage chamber 76 are open to the atmosphere, and the two flow valves 48 and 49 are open. The liquid in the first storage chamber 71 and the second storage chamber 76 is supplied to the liquid discharge unit 20 from both the supply flow channel 46 and the recovery flow channel 47, as indicated by the arrows in Figure 2. This supply of liquid to the liquid discharge unit 20 is achieved by the difference in water head between the liquid levels in the first storage chamber 71 and the second storage chamber 76 and the liquid level (meniscus) in the nozzle 21N of the liquid discharge unit 20.

[0047] During maintenance, the first storage chamber 71 is open to the atmosphere, and the second storage chamber 76 is pressurized. With the two flow valves 48 and 49 open, the liquid in the second storage chamber 76 is recovered into the first storage chamber 71 via the liquid discharge section 20. In other words, a liquid circulation occurs in which the liquid supplied from the second storage chamber 76 to the liquid discharge section 20 is recovered from the liquid discharge section 20 into the first storage chamber 71.

[0048] If the liquid is, for example, a pigment ink containing pigment, the circulation of the liquid suppresses the settling of the pigment in the liquid. In addition, a filter (not shown) is provided in the liquid storage section 40 or the liquid discharge section 20 in the middle of the liquid circulation path. As the liquid circulates, foreign matter such as air bubbles in the liquid is removed by the filter.

[0049] <Regarding the liquid discharge unit 20 and maintenance unit 25> The liquid dispensing unit 20 shown in Figure 2 dispenses liquid supplied from the liquid storage unit 40. The liquid dispensing unit 20 has a dispensing head 21. The dispensing head 21 has one or more nozzles 21N. The dispensing head 21 has a nozzle opening surface 21A through which the nozzles 21N open. The liquid dispensing unit 20 is positioned so that the nozzle opening surface 21A of the dispensing head 21 faces the transport path of the medium M. The liquid dispensing unit 20 prints on the medium M by dispensing ink, which is an example of a liquid, from the nozzles 21N.

[0050] The liquid ejection device 11 includes a maintenance unit 25 for maintaining the nozzle 21N of the ejection head 21. The maintenance unit 25 has a cap 26 that can contact the nozzle opening surface 21A. When the cap 26 is in a capping state, in contact with the nozzle opening surface 21A, it suppresses the viscosity increase of liquid such as ink inside the nozzle 21N when not printing. The maintenance unit 25 performs cleaning as one of its maintenance functions. Cleaning is performed by forcibly discharging liquid from the nozzle 21N under the capping state of the cap 26 shown in Figure 2. Cleaning removes viscous liquid and foreign matter such as air bubbles inside the nozzle 21N. The ejection head 21 also performs flushing as one of its maintenance functions, discharging liquid such as ink unrelated to printing from the nozzle 21N. In this way, the liquid ejection unit 20 consumes liquid through printing and maintenance such as cleaning and flushing.

[0051] <Configuration of the transfer unit 60> As shown in Figure 2, the transfer unit 60 transfers liquid from the liquid container 30 to the liquid storage unit 40 via the mounting unit 50. The transfer unit 60 has the function of generating the pressure necessary to be applied to the liquid level P2 in the liquid storage unit 40 when transferring liquid from the liquid container 30 to the liquid storage unit 40. The transfer unit 60 also has the function of generating the supply pressure to supply the liquid in the liquid storage unit 40 to the liquid discharge unit 20.

[0052] The transfer unit 60 includes a depressurization unit 61, a pressurization unit 62, and an atmospheric release unit 63. In this embodiment, the transfer unit 60 uses the depressurization unit 61 and the atmospheric release unit 63 when the transfer mode is executed. The depressurization section 61 depressurizes the second storage chamber 76. In this embodiment, the depressurization section 61 can depressurize the first storage chamber 71 and the second storage chamber 76 individually. The pressurization section 62 can pressurize the first storage chamber 71 and the second storage chamber 76 individually. The atmospheric release section 63 can release the first storage chamber 71 and the second storage chamber 76 to the atmosphere individually. The atmospheric release section 63 includes a first atmospheric release section 63A and a second atmospheric release section 63B. The first atmospheric release section 63A releases the first storage chamber 71 to the atmosphere. The second atmospheric release section 63B releases the second storage chamber 76 to the atmosphere.

[0053] The transfer unit 60 includes a selector valve 80, a pressure reducing pump 64 which constitutes the pressure reducing unit 61, and a pressure increasing pump 65 which constitutes the pressure increasing unit 62. The selector valve 80 includes a pressure switching mechanism 81, on-off valves 82 and 83, an atmospheric release valve 84, a first on-off valve 86, and a second on-off valve 87. The pressure switching mechanism 81 is connected to a depressurizing passage 81A, a pressurizing passage 81B, an atmospheric passage 81C, a detection passage 81D, a first air passage 88, and a second air passage 89.

[0054] The pressure-reducing passage 81A is provided with an on-off valve 82 and a pressure-reducing pump 64. The pressure-reducing passage 81B is provided with an on-off valve 83 and a pressure-reducing pump 65. The atmospheric passage 81C is provided with an atmospheric release valve 84. The detection passage 81D is connected to a pressure sensor 85. The first air passage 88 is provided with a first on-off valve 86. The second air passage 89 is provided with a second on-off valve 87.

[0055] The pressure switching mechanism 81 includes a plurality of valves (not shown) inside. The pressure switching mechanism 81 individually directs the pressures introduced by the depressurization section 61, the pressurization section 62, and the atmospheric release section 63 to the first air passage 88 and the second air passage 89.

[0056] When the pressure reducing pump 64 is driven while the on-off valve 82 is open and both the on-off valve 83 and the atmospheric release valve 84 are closed, negative pressure is generated within the pressure switching mechanism 81. The pressure switching mechanism 81 can be selected as the destination for this negative pressure. When the first on-off valve 86 is opened while this negative pressure is generated, the air chamber 73 of the first storage chamber 71 is depressurized. Also, when the second on-off valve 87 is opened while this negative pressure is generated, the air chamber 78 of the second storage chamber 76 is depressurized.

[0057] When the pressurizing pump 65 is driven with the on-off valve 83 in the open state and the on-off valve 82 and atmospheric release valve 84 in the closed state, positive pressure is generated within the pressure switching mechanism 81. The destination of this positive pressure can be selected by the pressure switching mechanism 81. When the first on-off valve 86 is opened while this positive pressure is generated, the air chamber 73 in the first storage chamber 71 is pressurized. Also, when the second on-off valve 87 is opened while this positive pressure is generated, the air chamber 78 in the second storage chamber 76 is pressurized.

[0058] With the atmospheric release valve 84 open and the on-off valves 82 and 83 closed, the pressure inside the pressure switching mechanism 81 becomes atmospheric pressure. When the first on-off valve 86 is opened in this atmospheric pressure state, the air chamber 73 inside the first storage chamber 71 is opened to the atmosphere. The first atmospheric release section 63A is formed by the flow path 81C, the atmospheric release valve 84, the pressure switching mechanism 81, the first air flow path 88, and the first on-off valve 86, which open the inside of the first storage chamber 71 to the atmosphere.

[0059] Furthermore, when the second on-off valve 87 is opened while the pressure is at atmospheric pressure, the air chamber 78 of the second storage chamber 76 is opened to the atmosphere. The second atmospheric opening section 63B is formed by the flow path 81C, atmospheric opening valve 84, pressure switching mechanism 81, second air flow path 89, and second on-off valve 87, which open the inside of the second storage chamber 76 to the atmosphere.

[0060] The control unit 100 controls the liquid discharge unit 20, the first flow path valve 48, the second flow path valve 49, and the transfer unit 60. In this embodiment, when the first remaining amount L1 in the liquid container 30 falls below the first threshold R1, the control unit 100 executes a transfer mode in which the liquid in the liquid container 30 is transferred to the liquid storage unit 40. In this embodiment, in the transfer mode, the first storage chamber 71 is opened to the atmosphere by the first atmospheric release unit 63A, and the second storage chamber 76 is depressurized to pressure Pn by the depressurization unit 61.

[0061] The first atmospheric opening section 63A is configured to allow the inside of the first storage chamber 71 to be opened to the atmosphere. Within the first storage chamber 71, an air chamber 73 is formed by the space above the liquid level P2 of the liquid in which the liquid is stored. The first atmospheric opening section 63A has a moisture-permeable membrane 74 provided on the upper part of the first housing 72. The space outside the moisture-permeable membrane 74 is configured to communicate with the atmosphere.

[0062] The second atmospheric opening section 63B is configured to allow the inside of the second storage chamber 76 to be opened to the atmosphere. Within the second storage chamber 76, an air chamber 78 is formed by the space above the liquid level P3 of the liquid in which the liquid is stored. The second atmospheric opening section 63B has a moisture-permeable membrane 79 provided on the upper part of the second housing 77. The space outside the moisture-permeable membrane 79 is configured to communicate with the atmosphere.

[0063] The transfer unit 60 transfers liquid by supplying liquid to the liquid supply unit 56, even if the liquid level P2 in the liquid storage unit 40 is not below the standard liquid level SP. The transfer unit 60 transfers liquid from the liquid container 30 to the liquid storage unit 40 via the attachment unit 50 by adjusting the air pressure in the liquid storage unit 40 to lower the liquid level P2 to below the reference liquid level SP.

[0064] The control unit 100 executes the transfer mode by first reducing the pressure inside the second storage chamber 76 with the transfer unit 60 to bring the liquid level P2 in the first storage chamber 71 below the reference liquid level SP, and then opening the second storage chamber 76 to the atmosphere.

[0065] <Configuration of mounting section 50 and liquid supply mechanism 56> Next, the configuration of the mounting section 50 and the liquid supply section 56 will be described with reference to Figures 3 and 4. As shown in Figure 3, the liquid container 30 has a valve body 34, a valve seat 35, and a spring 36 inside the supply section 32 that biases the valve body 34 in a direction that presses it against the valve seat 35.

[0066] As shown in Figure 3, the supply portion 51 of the mounting portion 50 has a needle-shaped connection portion 54. The connection portion 54 has a communication passage 55 that penetrates in its axial direction. Before the liquid container 30 is mounted on the mounting portion 50, the supply portion 32 is closed by the valve body 34 contacting the valve seat 35. When the liquid container 30 is mounted on the mounting portion 50, the connection portion 54 pushes the valve body 34, causing the valve body 34 and the valve seat 35 to separate. This connects the supply portion 32 and the supply portion 51 in a state of communication.

[0067] A cylindrical replenishment channel 58 is formed on the lower side of the supply section 51. The liquid container 30, which is attached to the mounting section 50, is connected to the liquid storage section 40 via the supply section 51 and the replenishment channel 58. The supply section 51 may also be configured such that a member having a connection section 54 moves relative to the replenishment channel 58.

[0068] The liquid supply unit 56 of this embodiment is composed of, for example, a gas-liquid exchange unit 57 that supplies liquid by gas-liquid exchange. When the liquid level P2 falls below the reference liquid level SP, the gas-liquid exchange unit 57 sends air from the air chamber 73 on the liquid storage unit 40 side to the mounting unit 50 side, and a liquid of approximately the same volume as that air is sent from the supply channel 58 to the liquid storage unit 40 side. The gas-liquid exchange unit 57 has a supply channel 58 and a partition wall 59 that forms the supply channel 58.

[0069] As shown in Figure 4, due to ink consumption in the liquid discharge unit 20, the liquid level P2 drops below the reference liquid level SP. When the liquid level P2 drops below the reference liquid level SP, gas-liquid exchange becomes possible as air in the air chamber 73 moves to the supply channel 58 side via the lower side of the lower end 59A of the partition wall 59. In gas-liquid exchange, liquid of approximately the same volume as the bubbles B1 moves from the supply channel 58 to the first storage chamber 71. In other words, liquid is supplied from the liquid container 30 to the first storage chamber 71 via the supplied part 51 of the mounting part 50. When the liquid level P2 drops below the reference liquid level SP, the gas-liquid exchange unit 57 supplies liquid from the liquid container 30 to the liquid storage unit 40 through gas-liquid exchange. For this reason, the liquid level P2 in the liquid storage unit 40 is generally maintained at or near the reference liquid level SP.

[0070] <Configuration of detection unit 90> Next, an example of the configuration of the detection unit 90, which consists of physical sensors, will be described with reference to Figures 5 and 6. The first detection unit 90, which is an example of a detection unit, is composed of physical sensors that detect when the first remaining amount L1 in the liquid container 30 has reached or below a first threshold R1. The first threshold R1 is, for example, the near end.

[0071] As shown in Figure 5, the first detection unit 90 is composed of a prism 91 and an optical sensor 92, which are positioned at a location corresponding to the liquid level height of the first threshold R1 in the liquid container 30. The position of the first detection unit 90 can be on the side or bottom of the main body 31, as long as it is a position where it is possible to detect that the first remaining amount L1 has fallen below the first threshold R1. For example, as shown in Figure 5, the first detection unit 90 may be provided on the side of the main body 31. Alternatively, the first detection unit 90 may be provided on the bottom of the main body 31, as shown by the dashed line in Figure 5.

[0072] As shown in Figure 6, the liquid container 30 has a window 31A at a position corresponding to the liquid level height of the first threshold R1 in the main body 31. The prism 91 is positioned inside the window 31A. In a side view of the prism 91, taken from a direction perpendicular to the plane of the paper in Figure 6, the cross-section of the prism 91 is triangular. The prism 91 has three faces 93 to 95, corresponding to the sides of the triangle. The first face 93 of the prism 91 is positioned to block the window portion 31A and is facing the optical sensor 92. The other two faces of the prism 91, the second face 94 and the third face 95, are positioned at an acute angle (for example, about 45°) with respect to the direction facing the optical sensor 92.

[0073] The optical sensor 92 has a light-emitting unit 96 and a light-receiving unit 97. Before the first remaining amount L1 in the liquid container 30 reaches a first threshold R1 (for example, near end), light incident from the light-emitting unit 96 of the optical sensor 92 onto the prism 91 passes through the prism 91. As a result, the optical sensor 92 enters a non-detection state when the light-receiving detection value received by the light-receiving unit 97 falls below the detection threshold. When the first remaining amount L1 in the liquid container 30 falls below the first threshold R1, light from the light-emitting unit 96 of the optical sensor 92 is reflected by the surfaces 94 and 95 of the prism 91, increasing the amount of light received by the light-receiving unit 97. As a result, the optical sensor 92 enters a detection state when the light-receiving detection value received by the light-receiving unit 97 exceeds the detection threshold. Thus, the first detection unit 90 detects that the first remaining amount L1 in the liquid container 30 has fallen below the first threshold R1 by changing from a non-detection state to a detection state. In this embodiment, the first detection unit 90 switches from a non-detection state to a detection state when the first remaining amount L1 of the liquid container 30 falls below the near end.

[0074] <Electrical configuration of liquid dispensing device 11> Next, the electrical configuration of the liquid dispensing device 11 will be described with reference to Figure 7. As shown in Figure 7, the liquid dispensing device 11 includes the control unit 100 described above. The control unit 100 comprehensively controls the liquid dispensing device 11. The control unit 100 may be configured as a circuit including α: one or more processors that execute various processes according to a computer program, β: one or more dedicated hardware circuits that execute at least some of the various processes, or γ: a combination thereof. The hardware circuit is, for example, an application-specific integrated circuit. The processor includes a CPU and a storage unit consisting of memory such as RAM and ROM. The storage unit stores program code or instructions configured to cause the CPU to execute processes. Memory, or computer-readable media, includes any readable media that can be accessed by a general-purpose or dedicated computer.

[0075] The control unit 100 can communicate with a host device (not shown) via a communication interface 101. The control unit 100 receives print data PD from the host device. The control unit 100 is electrically connected to an image reading unit 13, a display unit 17, an operation unit 18, a liquid discharge unit 20, a transport unit 28, flow path valves 48, 49, and a transfer unit 60. The control unit 100 is communicatively connected to a memory element 33 when the liquid container 30 is mounted on the mounting unit 50. The control unit 100 is also electrically connected to a sensor system consisting of a detection unit 90, a first detection unit 43, a second detection unit 44, and a pressure sensor 85. The transfer unit 60 includes a depressurization unit 61, a pressurization unit 62, and an atmospheric release unit 63. By controlling the transfer unit 60, the control unit 100 can individually depressurize, pressurize, and release the first storage chamber 71 and the second storage chamber 76 to the atmosphere.

[0076] The control unit 100 has a computer 110. The computer 110 includes a CPU 111 and a storage unit 112. The storage unit 112 stores the program PR and the remaining amount data RD. The control unit 100 has various software-based functional units by executing the program PR. The program PR also includes the transfer mode routine shown in Figure 12. The control unit 100 executes the transfer mode based on the program related to the transfer mode routine shown in the flowchart in Figure 12. The control unit 100 also writes the remaining amount data RD read from the storage element 33 to the storage unit 112. The control unit 100 obtains the amount of liquid consumed by the liquid dispensing unit 20 during printing and cleaning by counting it based on the print data PD and cleaning information. The control unit 100 updates the remaining amount data RD by subtracting the liquid consumption value from the value of the remaining amount data RD. When the power is turned OFF by operating the power switch 18A of the operation unit 18, the control unit 100 writes the latest remaining amount data RD to the storage element 33.

[0077] <Functional configuration of the control unit 100> Next, with reference to Figure 8, the configuration of the functions provided by the control unit 100 (CPU 111) when it executes program PR will be described. As shown in Figure 8, the control unit 100 has a functional configuration consisting of software, including a liquid consumption counting unit 121, a first acquisition unit 122, a detection unit 123, a transfer control unit 124, a second acquisition unit 125, a detection unit 126, a setting unit 127, and a notification processing unit 128.

[0078] The liquid consumption counting unit 121 counts the amount of liquid consumed by the liquid dispensing unit 20. The liquid consumption counting unit 121 counts the amount of liquid consumed for each color liquid container 30 by counting the number of dots in the image data included in the print data PD for each color. If there are multiple dot sizes for the print dots, the liquid consumption is counted by multiplying each dot by a coefficient corresponding to the dot size and counting the multiplied value. The liquid consumption counting unit 121 also counts the amount of liquid consumed during cleaning based on cleaning information. The cleaning information is, for example, table data that associates cleaning intensity with the amount of liquid consumed during cleaning at that cleaning intensity. Once the cleaning intensity is determined, the liquid consumption counting unit 121 refers to the cleaning information and obtains the amount of liquid consumed according to the cleaning intensity. The liquid consumption counting unit 121 obtains the amount of liquid consumed by the liquid dispensing unit 20 by counting the amount of liquid consumed during printing and the amount of liquid consumed during cleaning.

[0079] The first acquisition unit 122 acquires an estimated value of the first remaining amount L1 of the liquid container 30 as the first estimated remaining amount. The first acquisition unit 122 obtains the first estimated remaining amount by subtracting the liquid consumption amount from the remaining amount data RD.

[0080] The detection unit 123 is a soft sensor that has the same detection function as the physical sensor detection unit 90. The detection unit 123 detects, for example, the near end by determining whether the first estimated remaining amount has fallen below the first threshold R1. The first threshold R1 may be a threshold other than the near end. Note that either the detection unit 90 or the detection unit 123 may be present alone.

[0081] The transfer control unit 124 controls the transfer unit 60. The transfer control unit 124 individually adjusts the pressure in the first storage chamber 71 and the second storage chamber 76 by controlling the depressurization unit 61, pressurization unit 62, and atmospheric release unit 63, which constitute the transfer unit 60. In this embodiment, based on the detection results of the detection units 90 and 123, when the first remaining amount L1 falls below the first threshold R1, the transfer control unit 124 controls the depressurization unit 61 and the atmospheric release unit 63 to execute the transfer mode.

[0082] The second acquisition unit 125 acquires an estimated value of the second remaining amount L2 in the liquid storage unit 40 as the second estimated remaining amount. Before the transfer mode is executed, the second acquisition unit 125 estimates that the second remaining amount L2 in the liquid storage unit 40 is the amount of liquid corresponding to the reference liquid level SP. After the liquid container 30 is empty and replenishment stops, the second estimated remaining amount is obtained by subtracting the amount of liquid consumed from the amount of liquid corresponding to the reference liquid level SP. The second acquisition unit 125 determines that replenishment has stopped after the liquid container 30 is empty based on the first estimated remaining amount acquired from the first acquisition unit 122.

[0083] Here, the amount of liquid transferred in one transfer mode can be estimated by the pressure Pn and depressurization time T1 during depressurization. More specifically, the amount of liquid transferred in one transfer mode is predetermined as a target transfer amount. The pressure Pn and depressurization time T1 during depressurization are set so that the amount of liquid transferred becomes the target transfer amount. The second acquisition unit 125 may estimate a known target transfer amount as the amount of liquid transferred in one transfer mode. When the control unit 100 executes a transfer mode, it decreases the first estimated remaining amount by the estimated amount of liquid transferred in the transfer mode and increases the second estimated remaining amount. That is, the first acquisition unit 122 obtains the first estimated remaining amount immediately after the execution of the transfer mode by decreasing the first estimated remaining amount by the estimated amount of liquid transferred in the transfer mode. The second acquisition unit 125 obtains the second estimated remaining amount immediately after the execution of the transfer mode by increasing the second estimated remaining amount by the estimated amount of liquid transferred in the transfer mode.

[0084] The detection unit 126 is a soft sensor that has the same detection function as the physical sensor detection unit 43. The detection unit 126 detects when the second estimated remaining amount reaches the second threshold R2. Note that either the detection unit 43 or the detection unit 126 may be present alone.

[0085] The setting unit 127 sets at least one of the first estimated remaining amount, the second estimated remaining amount, and the usable estimated amount, which is selected based on the operation of the operation unit 18, to be displayed. The setting unit 127 displays, for example, the liquid volume display setting screen 130 shown in Figure 9 on the display unit 17. The liquid volume display setting screen 130 displays a message MS1 prompting the user to select the liquid volume to be displayed when it is time to replace the liquid container 30. The liquid volume display setting screen 130 also includes an option 131 for selecting the first estimated remaining amount, an option 132 for selecting the second estimated remaining amount, and an option 133 for selecting the usable estimated amount. The liquid volume display setting screen 130 also includes an OK button 134 operated by the user when making a setting and a Cancel button 135 operated when canceling without making a setting. The user selects at least one of the three options 131 to 133 and then operates the OK button 134 to set the selected liquid volume to be displayed when it is time to replace the liquid container 30. In the example setting screen 130 shown in Figure 9, options 131 and 133 are selected, and option 132 is not selected. A user who wants to display all three liquid volume options selects all three options 131 to 133, and then selects the OK button 134. When the setting unit 127 receives the selection result that the user made using the operation unit 18 on the setting screen 130, it sets the result by writing the received selection result to the setting storage area of ​​the storage unit 112.

[0086] The notification processing unit 128 performs information notification processing. The notification processing unit 128 performs notification processing by displaying information on the display unit 17 which has a notification function. When the first remaining amount L1 falls below the first threshold R1, the notification processing unit 128 causes the display unit 17, which functions as a notification unit, to notify information prompting the replacement of the liquid container 30. For example, the notification processing unit 128 displays the notification screen 136 shown in Figure 10 on the display unit 17. The notification screen 136 displays a message MS2 that notifies the user that the first remaining amount L1 of the liquid container 30 has fallen below the first threshold R1 (for example, near end), and prompts the user to replace the liquid container 30. After the user confirms the notification information, they operate the OK button 134.

[0087] Furthermore, after the transfer mode is executed, the notification processing unit 128 displays information on the display unit 17 that includes at least one of the following: the first estimated remaining amount, the second estimated remaining amount, and the usable estimated amount which is the sum of the first and second estimated remaining amounts. For example, the notification processing unit 128 displays the liquid volume information notification screen 137 shown in Figure 11 on the display unit 17. The liquid volume information notification screen 137 shown in Figure 11 displays a message MS11 that notifies the value L1 of the first estimated remaining amount, a message MS12 that notifies the value L2 of the second estimated remaining amount, and a message MS13 that notifies the value L3 of the usable estimated amount. The liquid volume information notification screen 137 displays the type and number of liquid volumes according to the selection made by the user on the liquid volume display setting screen 130 (Figure 9) and accepted by the setting unit 127. Figure 11 is an example of the display when the user has selected and set the display of all three types of liquid volumes. After the user confirms the notified liquid volume, they operate the OK button 134. The control unit 100 may also cause screens 130, 136, and 137 to be displayed on the display unit of the host device.

[0088] <Control details related to the transport mode by the control unit 100> When the first remaining amount L1, which is the amount of liquid in the liquid container 30, falls below the first threshold R1, the control unit 100 executes a transfer mode to transfer the liquid in the liquid container 30 to the liquid storage unit 40 until the second remaining amount L2, which is the amount of liquid in the liquid storage unit 40, falls below the second threshold R2.

[0089] Furthermore, after the transfer mode has been executed but before the liquid container 30 has been replaced, if the second remaining amount L2 becomes less than or equal to the third threshold R3, which is a value smaller than the second threshold R2, the control unit 100 will execute the transfer mode again.

[0090] If the control unit 100 detects that the first remaining amount L1 has reached its limit after executing a transfer mode, it will not execute another transfer mode. In other words, if the control unit 100 detects that the first remaining amount L1 has reached its limit, it will make the current transfer mode the final transfer mode.

[0091] On the other hand, if the control unit 100 does not detect that the first remaining amount L1 has reached its end after executing the transfer mode, it will execute the transfer mode again. The control unit 100 outputs an error if the detection unit 43 detects that the second remaining amount L2 has reached the second threshold R2, regardless of whether the transfer mode is executed. On the other hand, the control unit 100 does not output an error if the detection unit 43 detects that the second remaining amount L2 has reached the second threshold R2 due to the execution of the transfer mode. In other words, if the detection unit 43 detects that the second remaining amount L2 has reached the second threshold R2 due to the execution of the transfer mode, it does not output an error because this is due to the transfer of liquid and is not an error.

[0092] <Control method for liquid dispensing device 11> The control method for the liquid dispensing device 11 includes (A) and (B) as shown below. (A) When the first remaining amount L1, which is the amount of liquid in the liquid container 30, falls below the first threshold R1, a transfer mode is executed to transfer the liquid in the liquid container 30 to the liquid storage unit 40 until the second remaining amount L2, which is the amount of liquid in the liquid storage unit 40, falls below the second threshold R2. (B) If the second remaining amount L2 in the liquid storage unit 40 falls below the third threshold R3 after the transfer mode has been executed but before the liquid container has been replaced, the transfer mode shall be executed again. Note that (A) above corresponds to the processes in steps S11, S14-S19 in Figure 12. (B) above corresponds to the processes in steps S22, S14-S19.

[0093] <Operation of the First Embodiment> The operation of the liquid discharge device 11 in this embodiment will be explained with reference to the flowchart shown in Figure 12 and Figures 2, 13 to 18. In Figures 2, 13 to 18, the two flow path valves 48 and 49 are shown with white valve symbols in the open state and with black valve symbols in the closed state.

[0094] The user displays the settings screen 130 on the display unit 17 by selecting a setting item from the menu screen (home screen). On the settings screen 130, the user selects at least one of the first estimated remaining amount, the second estimated remaining amount, and the usable estimated amount, and then operates the OK button 134. The user's selection of the liquid amount to be displayed on the settings screen 130 is received by the settings unit 127. The settings unit 127 sets the selection result by storing it in a predetermined storage area of ​​the storage unit 112.

[0095] As shown in Figure 2, during printing, both flow valves 48 and 49 are opened, and the first storage chamber 71 and the second storage chamber 76 are opened to the atmosphere. The liquid in the first storage chamber 71 and the second storage chamber 76 is supplied to the liquid discharge section 20 from both the supply channel 46 and the recovery channel 47 by the difference in hydrostatic head.

[0096] When the liquid ejection device 11 is not printing, if the cleaning conditions are met, the maintenance unit 25 cleans the liquid ejection unit 20. Cleaning is performed by the ejection head 21 forcibly discharging liquid from the nozzle 21N toward the cap 26 while the nozzle opening surface 21A of the ejection head 21 is capped by the cap 26. When the liquid ejection device 11 is neither printing nor cleaning, it is in liquid circulation or standby mode. During liquid circulation, both flow valves 48 and 49 are open, and the second storage chamber 76 is pressurized while the first storage chamber 71 is open to the atmosphere. Liquid (e.g., ink) is circulated along the circulation channel 23. In standby mode, both flow valves 48 and 49 are closed.

[0097] The liquid transfer mode routine executed by the control unit 100 is described below. The control unit 100 may prioritize this routine over cleaning if cleaning has not yet been initiated. Also, if a print job is received before the start of the transfer mode, printing based on the print job may be prioritized over the execution of the transfer mode. When the liquid ejection device 11 is powered ON, the control unit 100 executes the transfer mode routine at predetermined cycle times. Note that during the initialization operation when the liquid ejection device 11 is powered ON, the control unit 100 sets the value of a counter (not shown) indicating the number of transfer mode executions N to "1" (N=1).

[0098] First, in step S11, the control unit 100 determines whether the first remaining amount L1 of the liquid container is less than or equal to the first threshold R1. The determination of whether the first remaining amount L1 is less than or equal to the first threshold R1 is made based on the detection results of the detection units 90 and 123. The control unit 100 uses at least one of the detection results of the detection unit 90, which is a physical sensor such as an optical sensor, and the detection results of the detection unit 123, which is a soft sensor, to determine whether the first remaining amount L1 is less than or equal to the first threshold R1. If the first threshold R1 is, for example, near end, the control unit 100 determines whether the first remaining amount L1 has fallen below the near end. If the first remaining amount L1 is less than or equal to the first threshold R1, the process proceeds to step S12; otherwise, the process terminates. For example, as shown in Figure 13, when the first remaining amount L1 in the liquid container 30 falls below the first threshold R1, the process proceeds to step S12.

[0099] In step S12, the control unit 100 determines whether printing or cleaning is in progress. If printing or cleaning is not in progress, the control unit 100 proceeds to step S13. If printing or cleaning is in progress, it waits until printing or cleaning is completed.

[0100] In step S13, the control unit 100 determines whether it is the first time the transfer mode has been performed (N=1). If N=1, proceed to step S14; otherwise, proceed to step S22. In this case, since the transfer mode has not been performed even once, N=1, so proceed to step S14.

[0101] In step S14, the control unit 100 closes the circulation channel 23. As shown in Figure 13, the control unit 100 closes the supply channel 46 and the recovery channel 47 by closing the flow valves 48 and 49. As a result, communication between the liquid storage section 40 and the liquid discharge section 20 is cut off. Note that when the liquid discharge device 11 was in standby mode, the flow valves 48 and 49 were already in a closed state, so that closed state is maintained.

[0102] In the next step S15, the control unit 100 opens the first storage chamber 71 to the atmosphere. The control unit 100 activates the first atmospheric release section 63A of the transfer section 60 and opens both the atmospheric release valve 84 and the first on-off valve 86. As a result, the first storage chamber 71 is opened to the atmosphere through the air passage 88 from the first atmospheric release section 63A.

[0103] In the next step S16, the control unit 100 reduces the pressure in the second storage chamber 76 to Pn. The control unit 100 activates the pressure reduction unit 61 of the transfer unit 60 and opens both the on-off valve 82 and the second on-off valve 87. As a result, the negative pressure introduced into the second storage chamber 76 from the pressure reduction unit 61 through the air passage 89 reduces the pressure in the second storage chamber 76 to Pn. As a result, as shown in Figure 14, the liquid level P3 in the second storage chamber 76 is raised by the negative pressure, and the liquid in the first storage chamber 71 moves to the second storage chamber 76 through the outlet passage 41. The liquid level P2 in the first storage chamber 71 falls below the reference liquid level SP, enabling gas-liquid exchange by the gas-liquid exchange unit 57 that constitutes the liquid supply unit 56. The control unit 100 also starts timing the pressure reduction time T1 when the pressure reduction begins.

[0104] In the next step S17, the control unit 100 determines whether or not the depressurization time T1 has elapsed. If the depressurization time T1 has not elapsed, the control unit 100 remains in standby mode; if the depressurization time T1 has elapsed, it proceeds to step S18. As shown in Figure 15, during the depressurization time T1, liquid is transferred from the liquid container 30 to the first storage chamber 71 by the liquid supply unit 56, accompanied by gas-liquid exchange.

[0105] In the next step S18, the control unit 100 opens the second storage chamber 76 to the atmosphere. That is, the control unit 100 controls the transfer unit 60 to stop the driving of the depressurization unit 61 and opens both the atmospheric release valve 84 and the second on-off valve 87. As a result, the second storage chamber 76 is opened to the atmosphere through the air passage 89 by the second atmospheric release unit 63B.

[0106] In the next step S19, the control unit 100 opens the circulation channel. As shown in Figure 16, the control unit 100 opens the supply channel 46 and the recovery channel 47 that constitute the circulation channel 23 by opening the flow valves 48 and 49. The first storage chamber 71 and the second storage chamber 76 are now in communication through the circulation channel 23. As a result, the liquid in the second storage chamber 76 moves to the first storage chamber 71 through the circulation channel 23 due to the difference in water head between the liquid level P3 that had risen in the second storage chamber 76 (as shown in Figure 15) and the liquid level P2 that was at a height close to the reference liquid level SP in the first storage chamber 71. In this way, the liquid level P2 in the first storage chamber 71 and the liquid level P3 in the second storage chamber 76 become the same height. The liquid levels P2 and P3 immediately after the end of the transfer mode shown in Figure 16 are higher than the liquid levels P2 and P3 before the start of the transfer mode shown in Figure 13, by the amount of liquid transferred from the liquid container 30 to the first storage chamber 71. The amount of liquid transferred per transfer mode is set to the amount of liquid that causes the liquid level P2 to reach the upper limit of the second remaining amount L2. Immediately after the end of the transfer mode, the first detection unit 43 detects that the first remaining amount L1 has reached the second threshold R2. That is, the first detection unit 43 detects that the amount of liquid equivalent to one transfer mode has been transferred from the liquid container 30 to the first storage chamber 71.

[0107] In the next step S20, the control unit 100 determines whether the second remaining amount L2 in the first storage chamber 71 has reached the second threshold R2. That is, the control unit 100 determines whether the detection unit 43 has detected that the second remaining amount L2 has reached the second threshold R2. The control unit 100 determines that the second remaining amount L2 has reached the second threshold R2 when the detection unit 43 detects that the liquid level P2 has risen to a height above the upper limit. If the control unit 100 determines that the second remaining amount L2 has reached the second threshold R2, it proceeds to step S21. On the other hand, if the control unit 100 determines that the second remaining amount L2 has not reached the second threshold R2, it terminates this routine. In other words, it can be inferred that there is no liquid volume left in the liquid container 30 immediately before the start of the transfer mode for one transfer mode, and that the liquid container 30 has reached its end after the transfer mode has been executed. Therefore, since further execution of the transfer mode is unnecessary, this routine is terminated.

[0108] In step S21, the control unit 100 increments the number of transport mode executions N (N = N + 1). Then, the control unit 100 returns to step S11. Once a transfer mode is completed, the control unit 100 decreases the first estimated remaining amount by the amount of liquid transferred during the transfer mode, and increases the second estimated remaining amount. In other words, the control unit 100 updates the first and second estimated remaining amounts to the values ​​immediately after the transfer mode was executed. Furthermore, the control unit 100 calculates the usable estimated amount by adding the first and second estimated remaining amounts.

[0109] Furthermore, the control unit 100 reads the user selection information set by the setting unit 127. The control unit 100 displays at least one of the updated first estimated remaining amount, the second estimated remaining amount, and the usable estimated amount, selected based on the selection information, on the display unit 17. For example, the liquid level information notification screen 137 shown in Figure 11 is displayed on the display unit 17. A user who views the liquid level information notification screen 137 can obtain the desired liquid level information that they have selected from the first estimated remaining amount, the second estimated remaining amount, and the usable estimated amount.

[0110] Furthermore, if the determination in step S11 indicates that the first remaining amount L1 is below the first threshold R1, the control unit 100 displays the notification screen 136 shown in Figure 10 on the display unit 17. The notification screen 136 displays a message MS2 prompting the user to replace the liquid container 30. If a user who sees message MS2 replaces the liquid container 30, the first remaining amount L1 remaining in the replaced used liquid container 30 will have decreased by at least the amount transferred compared to the liquid volume at the near-end. On the other hand, some users continue to use the liquid container 30 even after the near-end. As the liquid is consumed by subsequent printing or cleaning, the liquid level P2 of the second remaining amount L2 in the first storage chamber 71 gradually drops from the upper limit. Eventually, the second remaining amount L2 in the first storage chamber 71 falls below the third threshold R3.

[0111] In step S11, the first remaining amount L1 of the liquid container 30 is less than or equal to the first threshold R1, in step S12, neither printing nor cleaning is taking place, and in step S13, N=2, so the process proceeds to step S22.

[0112] In step S22, the control unit 100 determines whether the second remaining amount L2 in the first storage chamber 71 is less than or equal to the third threshold R3. If the second remaining amount L2 is not less than or equal to the third threshold R3, the process in steps S11 to S12 and step S22 is repeatedly executed until the second remaining amount L2 becomes less than or equal to the third threshold R3. Then, in step S22, if the second remaining amount L2 becomes less than or equal to the third threshold R3, the process proceeds to step S14.

[0113] Thus, the second transport mode is executed by carrying out the processes from steps S14 to S19. As shown in Figure 17, with the two flow valves 48 and 49 closed and the first storage chamber 71 open to the atmosphere, the second storage chamber 76 is depressurized. As the liquid level P3 in the second storage chamber 76 rises, the liquid in the first storage chamber 71 moves to the second storage chamber 76 through the outlet channel 41 and the one-way valve 42. As a result, the liquid level P2 in the second storage chamber 76 drops to a height shown by the dashed line in Figure 17, which is below the reference liquid level SP. Liquid is transferred from the liquid container 30 to the first storage chamber 71 through gas-liquid exchange by the liquid supply unit 56.

[0114] Subsequently, after the depressurization time T1 has elapsed in step S17, the second storage chamber 76 is opened to the atmosphere (step S18). Furthermore, in step S19, both flow valves 48 and 49 are opened, opening the circulation passage 23. As a result, due to the difference in water head between the liquid level P2 of the first storage chamber 71 and the liquid level P3 of the second storage chamber 76, as shown in Figure 17, the liquid in the second storage chamber 76 moves to the first storage chamber 71 through the circulation passage 23. Consequently, as shown in Figure 18, the liquid level P2 of the first storage chamber 71 and the liquid level P3 of the second storage chamber 76 become the same height.

[0115] In step S20, if the second remaining amount L2 in the first storage chamber 71 reaches the second threshold R2, the transfer mode execution count N is incremented in step S21. On the other hand, if the liquid level P2 shown by the dashed line in Figure 18 does not reach the second threshold R2, it can be presumed that the liquid container 30 has reached its end, and this routine is terminated.

[0116] Thus, in step S20, the control unit 100 repeats the consumption of liquid and the execution of the transfer mode until the second remaining amount L2 no longer reaches the second threshold R2. The execution of the transfer mode is repeated until the liquid container 30 is finally run out. When the user replaces the liquid container 30, it is highly likely that the liquid container 30 being replaced is run out. Furthermore, even if the liquid container 30 being replaced is not run out, it is highly likely that the first remaining amount L1 remaining in that liquid container 30 is considerably less than the first remaining amount L1 at the near-end. Therefore, the waste of liquid remaining in the replaced liquid container 30 is suppressed.

[0117] <Effects of the First Embodiment> The effects of this embodiment will now be explained. (1-1) When the first remaining amount L1, which is the amount of liquid in the liquid container 30, falls below the first threshold R1, the control unit 100 executes a transfer mode to transfer the liquid in the liquid container 30 to the liquid storage unit 40 until the second remaining amount L2, which is the amount of liquid in the liquid storage unit 40, falls below the second threshold R2. Furthermore, after executing the transfer mode but before the liquid container 30 is replaced, if the second remaining amount L2 falls below the third threshold R3, which is a value smaller than the second threshold R2, the control unit 100 executes the transfer mode again. With this configuration, after executing the transfer mode, if the second remaining amount L2 in the liquid storage unit 40 becomes small, the transfer mode is executed again to transfer liquid to the liquid storage unit 40. The amount of liquid remaining in the liquid container 30 that could not be sent in one transfer mode can be reduced by further transfer. The amount of liquid remaining in the liquid container 30 when it is replaced can be further reduced.

[0118] (1-2) The liquid dispensing device 11 includes detection units 90 and 123 that detect when the first remaining amount L1 of the liquid container 30 has reached its limit. If the control unit 100 detects that the first remaining amount L1 has reached its limit after executing the transfer mode, it will not execute the transfer mode again. On the other hand, if the control unit 100 does not detect that the first remaining amount L1 has reached its limit after executing the transfer mode, it will execute the transfer mode again. With this configuration, if the first remaining amount L1 reaches its limit after executing the transfer mode, it is not necessary to execute the transfer mode again. Therefore, unnecessary execution of the transfer mode can be avoided. For example, delays in the replacement of the liquid container 30 and delays in the start of printing caused by unnecessary execution of the transfer mode can be avoided.

[0119] (1-3) The liquid dispensing device 11 is equipped with a detection unit 43 that physically detects when the second remaining amount L2 reaches the second threshold R2. Therefore, because it is detected physically, the remaining amount can be reliably managed. For example, it can be confirmed that the liquid was transferred without errors in the transfer mode. Also, for example, by confirming that not enough liquid was transferred in the transfer mode, it can be estimated that the liquid container 30 is empty or has definitely reached its end.

[0120] (1-4) The detection unit 43 also functions as an error detection unit that detects when the second remaining amount L2 reaches the second threshold R2 as an error. The control unit 100 outputs an error when the detection unit 43 detects that the second remaining amount L2 has reached the second threshold R2, regardless of whether the transfer mode is executed. On the other hand, the control unit 100 does not output an error when the detection unit 43 detects that the second remaining amount L2 has reached the second threshold R2 due to the execution of the transfer mode. With this configuration, since no error is output when the second remaining amount reaches the second threshold due to the execution of the transfer mode, user confusion caused by the output of an error can be suppressed. If the detection unit 43 is also used as an overflow sensor, it can suppress the display of an error caused by the detection of an overflow.

[0121] (1-5) The first acquisition unit 122 acquires the first remaining amount L1 of the liquid container 30 as the first estimated remaining amount. The second acquisition unit 125 acquires the second remaining amount L2 of the liquid storage unit 40 as the second estimated remaining amount. When the control unit 100 executes the transfer mode, it decreases the first estimated remaining amount by the estimated amount of liquid transferred in the transfer mode and increases the second estimated remaining amount. With this configuration, the occurrence of a difference between the actual remaining amount and the estimated remaining amount can be suppressed. Therefore, the amount of usable liquid can be appropriately managed.

[0122] (1-6) After the transfer mode is executed, the control unit 100 (notification processing unit 128) displays information on the display unit 17 that includes at least one of the following: the first estimated remaining amount, the second estimated remaining amount, and the usable estimated amount which is the sum of the first estimated remaining amount and the second estimated remaining amount. With this configuration, the user can individually configure the display settings, thus improving usability.

[0123] (1-7) The operation unit 18 is operated when selecting at least one of the options displayed on the display unit 17. The setting unit 127 accepts and sets at least one of the first estimated remaining amount, the second estimated remaining amount, and the usable estimated amount to be displayed based on the selection made by the operation unit 18. With this configuration, the user can individually set the display settings, thus improving usability.

[0124] (1-8) The control unit 100 (notification processing unit 128) causes the display unit 17, which functions as a notification unit, to notify the user of information prompting the replacement of the liquid container 30 when the first remaining amount L1 falls below the first threshold R1. With this configuration, the user can know when it is time to replace the liquid container 30.

[0125] (1-9) The liquid dispensing device 11 includes a liquid supply unit 56 that supplies liquid from the liquid container 30 to the first storage chamber 71 via the mounting unit 50 when the liquid level P2 in the liquid storage unit 40 falls below the reference liquid level SP. The transfer unit 60 transfers liquid by supplying liquid to the liquid supply unit 56 even if the liquid level P2 in the liquid storage unit 40 is not below the reference liquid level SP. With this configuration, liquid can be transferred using the liquid supply unit 56.

[0126] (1-10) The liquid discharge device 11 includes a liquid supply unit 56 that supplies liquid from the liquid container 30 to the first storage chamber 71 via the attachment unit 50 when the liquid level P2 in the liquid storage unit 40 falls below the reference liquid level SP. The transfer unit 60 transfers liquid from the liquid container 30 to the liquid storage unit 40 via the attachment unit 50 by adjusting the air pressure in the liquid storage unit 40 to lower the liquid level P2 to below the reference liquid level SP. With this configuration, by lowering the liquid level P2 in the liquid storage unit 40 to below the reference liquid level SP, the liquid can be transferred using the liquid supply unit 56.

[0127] (1-11) The liquid storage unit 40 includes a first storage chamber 71, a discharge channel 41, a second storage chamber 76, a one-way valve 42, and a liquid supply unit 56. The first storage chamber 71 stores liquid. The first storage chamber 71 stores liquid supplied from the liquid container 30 via the attachment unit 50. One end of the discharge channel 41 is connected to the first storage chamber 71 to discharge the liquid from the first storage chamber 71. The second storage chamber 76 is connected to the other end of the discharge channel 41 and stores the liquid supplied from the first storage chamber 71. The one-way valve 42 is provided in the discharge channel 41. The one-way valve 42 restricts the direction in which liquid flows through the discharge channel to one direction, from the first storage chamber 71 to the second storage chamber 76. The liquid supply unit 56 is provided to supply liquid from the liquid container 30 to the first storage chamber 71 via the attachment unit 50 when the liquid level P2 in the liquid storage unit 40 falls below the reference liquid level SP. The depressurization unit 61 depressurizes the second storage chamber 76. The first atmospheric release unit 63A is configured to allow the inside of the first storage chamber 71 to be opened to the atmosphere. The second atmospheric release unit 63B is configured to allow the inside of the second storage chamber 76 to be opened to the atmosphere. The control unit 100 executes the transfer mode by having the transfer unit 60 depressurize the inside of the second storage chamber 76 to bring the liquid level P2 in the first storage chamber 71 below the reference liquid level SP, and then opening the inside of the second storage chamber 76 to the atmosphere. With this configuration, the transfer mode can be executed by depressurizing even if the liquid supply unit does not have a liquid supply means such as a pump, thus simplifying the flow path configuration and suppressing waste of liquid remaining in the liquid container that is not used.

[0128] (1-12) The liquid dispensing device 11 includes a supply channel 46 that supplies liquid from the liquid storage section 40 to the liquid dispensing section 20, and a recovery channel 47 that recovers liquid from the liquid dispensing section 20 to the liquid storage section 40. With this configuration, the amount of liquid that can be held on the device side can be increased by the length of the channel for circulating the liquid, while suppressing the thickening of the liquid and recovering foreign matter such as air bubbles in the liquid through liquid circulation.

[0129] (1-13) A control method for a liquid dispensing device 11 comprising a liquid dispensing unit 20, a liquid storage unit 40, a mounting unit 50, and a transfer unit 60 includes the following (A) and (B). (A) When the first remaining amount L1, which is the amount of liquid in the liquid container 30, falls below the first threshold R1, a transfer mode is executed to transfer the liquid in the liquid container 30 to the liquid storage unit 40 until the second remaining amount L2, which is the amount of liquid in the liquid storage unit 40, falls below the second threshold R2. (B) After the transfer mode has been executed but before the liquid container 30 has been replaced, if the second remaining amount L2, which is the amount of liquid in the liquid storage section 40, falls below the third threshold R3, which is a value smaller than the second threshold R2, the transfer mode shall be executed again. This method allows for repeated transfer modes, increasing the frequency with which the amount of liquid remaining in the liquid container 30 before the user replaces it can be reduced. Therefore, it is possible to suppress the waste of unused liquid remaining in the liquid container.

[0130] [Second Embodiment] Next, a second embodiment will be described with reference to Figures 19 to 22. The configuration of the liquid dispensing device 11 is the same as in the first embodiment. Therefore, the same reference numerals are used for components similar to those in the first embodiment, and their descriptions are omitted. In the second embodiment, the contents of the transfer mode differ from those in the first embodiment. The following description will focus on the contents of the transfer mode executed by the control unit 100.

[0131] The liquid dispensing device 11 includes a liquid supply unit 22 similar to that of the first embodiment. The configuration of the liquid supply unit 22 is the same as that of the first embodiment. The liquid dispensing device 11 includes a liquid storage section 40, a mounting section 50, a transfer section 60, and a control unit 100. The liquid container 30 is mounted on the mounting section 50. The liquid in the liquid container 30 is supplied to the liquid storage section 40 via the mounting section 50. The liquid storage section 40 includes a first storage chamber 71, an outlet channel 41, a second storage chamber 76, a one-way valve 42, and a liquid replenishment section 56.

[0132] The first storage chamber 71 stores the liquid supplied from the liquid container 30 via the attachment part 50. One end of the outlet channel 41 is connected to the first storage chamber 71 to discharge the liquid from the first storage chamber 71. The second storage chamber 76 is connected to the other end of the outlet channel 41 and stores the liquid supplied from the first storage chamber 71. The one-way valve 42 restricts the direction in which the liquid flows through the outlet channel 41 to one direction, from the first storage chamber 71 to the second storage chamber 76.

[0133] The liquid supply unit 56 supplies liquid from the liquid container 30 to the first storage chamber 71 via the attachment unit 50 when the liquid level P2 in the first storage chamber 71 falls below the reference liquid level SP. The liquid supply unit 56 is, for example, a gas-liquid exchange unit 57, which supplies liquid from the liquid container 30 to the first storage chamber 71 by gas-liquid exchange when the liquid level P2 of the second remaining amount L2 falls below the reference liquid level SP.

[0134] The transfer unit 60 includes a pressurizing unit 62, a first atmospheric vent 63A, and a second atmospheric vent 63B. The pressurizing unit 62 pressurizes at least the first storage chamber 71 of the two storage chambers 76. The first atmospheric vent 63A is configured to allow the inside of the first storage chamber 71 to be opened to the atmosphere. The second atmospheric vent 63B is configured to allow the inside of the second storage chamber 76 to be opened to the atmosphere.

[0135] In the first embodiment, the transfer mode was performed using a depressurization unit 61, but in the second embodiment, the transfer mode is performed using a pressurization unit 62. The control unit 100 performs the transfer mode by pressurizing at least the first storage chamber 71 with the transfer unit 60 to bring the liquid level P2 of the first storage chamber 71 below the reference liquid level SP, and then opening the pressurized first storage chamber 71 to the atmosphere. The pressurization unit 62 in this embodiment can pressurize the first storage chamber 71 and the second storage chamber 76 individually. In the transfer mode, the control unit 100 pressurizes both the first storage chamber 71 and the second storage chamber 76.

[0136] <Operation of the second embodiment> Next, the operation of the liquid discharge device 11 in the second embodiment will be explained with reference to the flowchart shown in Figure 18 and Figures 2, 20 to 22. In Figures 2, 13 to 18, the two flow valves 48 and 49 are shown with white valve symbols in the open state and with black valve symbols in the closed state.

[0137] First, each of the processes in steps S31 to S34 is the same as the processes in steps S11 to S14 in the first embodiment. If, in step S31, the first remaining amount L1 of the liquid container 30 is less than or equal to the first threshold R1, and in step S32, neither printing nor cleaning is taking place, then in step S33, since this is the first transfer mode (N=1), the process proceeds to step S34.

[0138] The control unit 100 executes the first transfer mode by performing the processes in steps S34 to S37. Specifically, in step S34, the control unit 100 closes the circulation channel 23. That is, the control unit 100 closes both of the flow channel valves 48 and 49.

[0139] In the next step S35, the control unit 100 pressurizes the first storage chamber 71 and the second storage chamber 76 to a pressure of Pa. The control unit 100 activates the pressurizing unit 62 of the transfer unit 60 and opens the on-off valve 83, the first on-off valve 86, and the second on-off valve 87. As a result, the positive pressure introduced from the pressurizing unit 62 to the first storage chamber 71 and the second storage chamber 76 through the air passages 88 and 89 pressurizes the first storage chamber 71 and the second storage chamber 76 to a pressure of Pa. As a result, as shown in Figure 20, the liquid level P2 in the first storage chamber 71 and the liquid level P3 in the second storage chamber 76 are pressed down by the pressurization. The pressurization of the second storage chamber 76 prevents the liquid in the first storage chamber 71 from moving to the second storage chamber 76 via the outlet passage 41 and the one-way valve 42. With the movement of liquid to the second storage chamber 76 suppressed, the liquid in the first storage chamber 71 moves to the liquid container 30 through the supply channel 58 and the attachment section 50. At this time, the air in the liquid container 30 is compressed by pressurization.

[0140] As a result of the movement of this liquid into the liquid container 30, the pressurized liquid level P2 in the first storage chamber 71 drops below the reference liquid level SP. This enables gas-liquid exchange by the gas-liquid exchange unit 57, which constitutes the liquid supply unit 56. Then, as shown in Figure 21, the liquid in the liquid container 30 is transferred to the first storage chamber 71 by gas-liquid exchange by the gas-liquid exchange unit 57. The control unit 100 starts timing the pressurization time T2 when pressurization begins.

[0141] In the next step S36, the control unit 100 determines whether or not the pressurization time T2 has elapsed. If the pressurization time T2 has not elapsed, the control unit 100 remains in standby mode; if the pressurization time T2 has elapsed, it proceeds to step S37. As shown in Figure 21, during the pressurization time T2, liquid is transferred from the liquid container 30 to the first storage chamber 71 by the liquid supply unit 56, accompanied by gas-liquid exchange.

[0142] In the next step S37, the control unit 100 opens the first storage chamber 71 and the second storage chamber 76 to the atmosphere. That is, the control unit 100 controls the transfer unit 60 to stop the driving of the pressurizing unit 62 and opens the atmospheric release valve 84, the first on-off valve 86, and the second on-off valve 87. As a result, the first storage chamber 71 is opened to the atmosphere through the air passage 88 by the first atmospheric release unit 63A, and the second storage chamber 76 is opened to the atmosphere through the air passage 89 by the second atmospheric release unit 63B.

[0143] As shown in Figure 22, when both the first storage chamber 71 and the second storage chamber 76 are opened to the atmosphere, the pressurization is released, causing both the liquid level P2 in the first storage chamber 71 and the liquid level P3 in the second storage chamber 76 to rise. The liquid levels P2 and P3 immediately after the end of the transfer mode shown in Figure 22 are higher than the liquid levels P2 and P3 before the start of the transfer mode (for example, near the reference liquid level SP) by the amount of liquid transferred from the liquid container 30 to the first storage chamber 71. The amount of liquid transferred per transfer mode is set to the amount of liquid that causes the liquid level P2 to reach the upper limit of the second remaining amount L2.

[0144] In the next step S38, the control unit 100 determines whether the second remaining amount L2 in the first storage chamber 71 has reached the second threshold R2. That is, the control unit 100 determines whether the detection unit 43 has detected that the second remaining amount L2 has reached the second threshold R2. If the detection unit 43 detects that the liquid level P2 has risen to a height above the upper limit, the control unit 100 determines that the second remaining amount L2 has reached the second threshold R2. If the control unit 100 determines that the second remaining amount L2 has reached the second threshold R2, it proceeds to step S39. On the other hand, if the control unit 100 determines that the second remaining amount L2 has not reached the second threshold R2, it terminates this routine. In other words, immediately before the start of the transfer mode, there is no liquid volume left in the liquid container 30 for one transfer mode, and it can be inferred that the liquid container 30 has reached its end after the transfer mode has been executed. Therefore, since further execution of the transfer mode is unnecessary, this routine is terminated.

[0145] In step S39, the control unit 100 increments the number of transport mode executions N (N = N + 1). Then, the control unit 100 returns to step S31. In step S31, the first remaining amount L1 of the liquid container 30 is less than or equal to the first threshold R1, in step S32, neither printing nor cleaning is taking place, and in step S33, N=2, so the process proceeds to step S40.

[0146] In step S40, the control unit 100 determines whether the second remaining amount L2 in the first storage chamber 71 is less than or equal to the third threshold R3. If the second remaining amount L2 is not less than or equal to the third threshold R3, the processes in steps S31 to S33 and step S40 are repeatedly executed until it is determined in step S40 that the second remaining amount L2 is less than or equal to the third threshold R3. Then, in step S40, if the second remaining amount L2 becomes less than or equal to the third threshold R3, the process proceeds to step S34.

[0147] Thus, the control unit 100 executes the processes from step S34 to step S37 to perform the second transfer mode. The pressurized transfer mode shown in Figures 20 to 23 is performed, and the liquid equivalent to one transfer mode is transferred from the liquid container 30 to the first storage chamber 71.

[0148] Thus, in step S38, the control unit 100 repeats the consumption of liquid and execution of the transfer mode until the second remaining amount L2 no longer reaches the second threshold R2. When the user replaces the liquid container 30, the frequency of the liquid container 30 being replaced being the end container is high. Furthermore, even if the liquid container 30 being replaced is not the end container, the frequency of the first remaining amount L1 remaining in that liquid container 30 being considerably less than the first remaining amount L1 when it is near the end container is high. Therefore, the waste of liquid remaining in the replaced liquid container 30 is suppressed.

[0149] The control method for the liquid dispensing device 11 in the second embodiment is the same as the control method for the liquid dispensing device 11 shown in the first embodiment. In the control method for the liquid dispensing device 11, (A) corresponds to the processing in steps S31, S34 to S37 in Figure 19. (B) corresponds to the processing in steps S40, S34 to S37.

[0150] <Effects of the second embodiment> According to the second embodiment, the effects (1-1) to (1-13) of the first embodiment can be obtained in the same way, and the following effects can also be obtained.

[0151] (2-1) The liquid storage unit 40 includes a first storage chamber 71, an outlet channel 41, a second storage chamber 76, a one-way valve 42, and a liquid supply unit 56. The transfer unit 60 has a pressurizing unit 62, a first atmospheric release unit 63A, and a second atmospheric release unit 63B. The control unit 100 pressurizes at least the first storage chamber 71 by the transfer unit 60 to bring the liquid level P2 in the first storage chamber 71 below the reference liquid level SP, and then releases the pressurized first storage chamber 71 to the atmosphere to execute the transfer mode. With this configuration, even if the liquid supply unit 56 does not have a liquid supply means such as a pump, the transfer mode can be executed by pressurizing the first storage chamber 71. Therefore, the flow path configuration can be simplified while suppressing waste of liquid remaining in the liquid container 30 that is not used.

[0152] [Third Embodiment] Next, a third embodiment will be described with reference to Figure 23. In the above embodiments, the fact that the liquid container 30 had reached its end was estimated based on the detection result of the detection unit 43 after the transfer mode was executed. In contrast, in this embodiment, the liquid dispensing device 11 is equipped with a second detection unit 98 that physically detects that the first remaining amount L1 of the liquid container 30 has reached its end. As shown in Figure 23, the second detection unit 98 is composed of a prism 91 provided at a position corresponding to the liquid level height corresponding to the end of the liquid container 30 (for example, the ink end), and an optical sensor 92 positioned opposite the prism 91. The configuration of the prism 91 and the optical sensor 92 is the same as that which constitutes the detection unit 90 in the first embodiment, except that the liquid level height to be detected is the end threshold RE instead of the first threshold R1. Therefore, the optical sensor 92 has a light-emitting unit 96 and a light-receiving unit 97 (see Figure 6 for both).

[0153] The second detection unit 98 may be located at the bottom of the main body 31, as shown by the dashed line in Figure 23, as long as it can detect when the first remaining amount L1 falls below the end threshold RE. The second detection unit 98 may also be located on the side of the main body 31, at the bottom, or at the corner between the bottom and the side. Furthermore, the second detection unit 98 may be provided not only in the main body 31 but also in the supply unit 32. In other words, the liquid level of the end threshold RE may be within the supply unit 32.

[0154] Before the first remaining amount L1 in the liquid container 30 reaches the end threshold RE, light from the light-emitting unit 96 passes through the prism 91, so the light-receiving detection value of the optical sensor 92 is below the detection threshold. For this reason, the second detection unit 98 does not detect the end. When the first remaining amount L1 in the liquid container 30 falls below the end threshold RE, the light emitted by the light-emitting unit 96 is reflected by the prism 91, so the light-receiving detection value of the optical sensor 92 exceeds the detection threshold. As a result, the second detection unit 98 detects that the first remaining amount L1 in the liquid container 30 has reached its end.

[0155] In step S20 or step S38 of the transfer mode routine shown in Figure 12 or Figure 19, the control unit 100 determines whether the first remaining amount L1 in the liquid container 30 has reached the end. If the first remaining amount L1 has not reached the end, the process proceeds to step S21 or step S39. If the first remaining amount L1 has reached the end, the routine is terminated. Thus, in step S20 or step S38, the determination of whether the first remaining amount L1 in the liquid container 30 has reached the end may be made based on the detection result of the second detection unit 98. According to this embodiment, since the second detection unit, which consists of a physical sensor, detects that the liquid container 30 has reached the end, the liquid can be transferred to the liquid container 30 more reliably until it reaches the end, compared to a configuration in which the end is estimated by a soft sensor.

[0156] [Example of changes] This embodiment can be implemented with the following modifications. This embodiment and the following modifications can be combined with each other to the extent that they do not contradict each other technically.

[0157] As shown in Figures 24 and 25, the liquid storage unit 40 may have only one storage chamber. The liquid supply unit is not limited to the gas-liquid exchange unit 57, but may also be a pump 151 that functions as a supply means. For example, the pump 151 is provided in the flow path 150 that connects the mounting unit 50 and the liquid storage unit 40. The liquid container 30 is not limited to a liquid cartridge (e.g., an ink cartridge) that contains liquid such as ink, but may also be a liquid pack 31P (e.g., an ink pack) in which liquid such as ink is contained in a pack. The liquid storage unit 40 includes a storage chamber 141 for storing liquid. The storage chamber 141 is formed inside the housing 142. The liquid dispensing device 11 may include an electrode-type sensor 45 that detects the second remaining amount L2 in the storage chamber 141. The electrode-type sensor 45 may include a first detection unit 43 and a second detection unit 44. For example, when the second detection unit 44 detects that the second remaining amount L2 has fallen below the lower limit, a pump 151, which functions as a liquid replenishment unit, is driven to replenish liquid from the liquid container 30 to the liquid storage unit 40 via the mounting unit 50. A circulation channel 23 may be formed by connecting a liquid storage unit 40 having only one storage chamber 141 and a liquid discharge unit 20 through a supply channel 46 and a recovery channel 47. That is, it may include a supply channel 46 that supplies liquid from the liquid storage unit 40 to the liquid discharge unit 20, and a recovery channel 47 that recovers liquid from the liquid discharge unit 20 to the liquid storage unit 40. Pumps 152 and 153 may be provided in the supply channel 46 and the recovery channel 47, respectively. The pump 152 provided in the supply channel 46 is a supply pump, and the pump 153 provided in the recovery channel 47 is a recovery pump.

[0158] When the first remaining amount L1, which is the amount of liquid in the liquid container 30, falls below the first threshold R1 shown in Figure 24, the control unit 100 executes a transfer mode to transfer the liquid in the liquid storage unit 40 until the second remaining amount L2, which is the amount of liquid in the liquid storage unit 40, falls below the second threshold R2 shown in Figure 25. As shown in Figure 25, in the transfer mode, the control unit 100 transfers the liquid by driving the pump 151. In other words, the pump 151 functions as the transfer unit 60. The pump 151, which functions as a liquid replenishment unit, is used as the transfer unit. For example, when the first detection unit 43 detects that the second remaining amount L2 has fallen below the second threshold R2, the control unit 100 stops driving the pump 151. Furthermore, after the transfer mode has been executed but before the liquid container 30 is replaced, if the second remaining amount L2 falls below the third threshold R3, which is a value smaller than the second threshold R2, the control unit 100 executes the transfer mode again. The second detection unit 44 detects when the second remaining amount L2 falls below the third threshold R3. The third threshold R3 may be, for example, the lower limit (lower value) of the second remaining amount L2 detected by the second detection unit 44, or it may be a value other than the lower limit. The second detection unit that detects when the second remaining amount L2 falls below the third threshold R3 may be a soft sensor, and the system may be configured to execute the transport mode again when the estimated second remaining amount, which is an estimated value of the second remaining amount L2, falls below the third threshold R3.

[0159] The liquid discharge device 11 may not have a circulation channel 23 formed by a supply channel 46 and a recovery channel 47. For example, as shown in Figure 26, the liquid storage section 40 and the liquid discharge section 20 may be connected by only one supply channel 46. The supply of liquid from the liquid storage section 40 to the liquid discharge section 20 through the supply channel 46 may be performed by the difference in water head between the liquid storage section 40 and the liquid discharge section 20. The pump 151 is driven to replenish the liquid from the liquid container 30 to the liquid storage section 40 and to transfer the liquid from the liquid container 30 to the liquid storage section 40 in transfer mode. In other words, the pump 151 functions as a liquid replenishment section and a transfer section 60. In transfer mode, when the first detection section 43 detects that the liquid level P2 has reached the second threshold R2 shown by the dashed line in Figure 26 due to the transfer of liquid, the pump 151 is stopped. When the second detection unit 44 detects that the second remaining amount L2 has fallen below the third threshold R3, the control unit 100 executes the transfer mode again.

[0160] • In the transfer mode, the portion where the transferred liquid is stored may be a flow path. For example, a liquid storage section may be provided in the flow path as a buffer capable of storing liquid. For example, a variable-capacity liquid storage section 160 that functions as a buffer, as shown in Figures 27 and 28, may be provided in the flow path 47. In the same figures, an example is shown in which the liquid storage section 160 is provided in the recovery flow path 47, but the flow path may be other flow paths such as a supply flow path 46 or a replenishment flow path 150. Multiple liquid storage sections 160 may be provided in one flow path, or multiple liquid storage sections may be provided across multiple flow paths. As shown in Figure 27, the variable-capacity liquid storage section 160 comprises a liquid chamber 161 which is part of the flow path 47, a flexible section 162, an air chamber 163 separated from the liquid chamber 161 via the flexible section 162, and a spring 164 provided in the air chamber 163. The air flow path 165 is in communication with the air chamber 163. The spring 164 is biased in the direction of pushing the flexible portion 162. In other words, the spring 164 is biased in the direction of reducing the volume of the liquid chamber 161. The air chamber 163 is connected to a selector valve 80 which constitutes the transfer unit 60 shown in Figure 2, via an air passage 165. The selector valve 80 has an on-off valve (not shown) that can open and close the air passage 165. With this on-off valve open, the transfer unit 60 can switch between introducing negative pressure generated by the depressurization unit 61 into the air chamber 163 and introducing positive pressure generated by the pressurization unit 62 into the air chamber 163. The control unit 100 can switch the pressure introduced into the air chamber 163 via the air passage 165 between depressurization and pressurization by controlling the transfer unit 60.

[0161] The variable-capacity liquid storage unit 160 changes the volume of the liquid chamber 161, which is separated from the air chamber 163 by a flexible section 162, by depressurizing or pressurizing the air chamber 163 through the air passage 165. In other words, the variable-capacity liquid storage unit 160 changes the volume of the liquid chamber 161 by air pressure drive by the transfer unit 60. Before the transfer mode is started, the liquid storage unit 160 is in an initial state where the volume of the liquid chamber 161 is small, as shown in Figure 27. As shown in Figure 28, in the transfer mode, the control unit 100 depressurizes the air chamber 163 through the air passage 165 with the flow valve 49 closed, causing the flexible section 162 to bend and deform in a direction that increases the volume of the liquid chamber 161. As the volume of the liquid chamber 161 expands, the liquid drawn in from the liquid storage unit 40 is stored in the liquid chamber 161. In addition to the liquid storage section 40, liquid is also stored in the variable-capacity liquid storage section 160 provided in the flow path 47, thereby increasing the amount of liquid transferred per transfer mode. Therefore, even if some liquid remains when the liquid container 30 is replaced, it is easier to reduce the amount of liquid that remains. This further reduces the waste of liquid when the liquid container 30 is replaced while some liquid remains. The liquid stored in the liquid chamber 161 may be retained until the liquid container 30 is finished, empty, or replaced, or it may be returned to the liquid storage section 40 when the liquid level P2 drops due to liquid consumption, or it may be supplied to the liquid discharge section 20 for cleaning, etc.

[0162] In the first embodiment, during the transfer mode, the second storage chamber 76 is depressurized and the first storage chamber 71 is opened to the atmosphere, but the second storage chamber 76 may be depressurized and the first storage chamber 71 may be pressurized. In this configuration, where the transfer mode is performed using liquid replenishment by the liquid replenishment unit 56, the method of pressure adjustment to lower the liquid level P2 of the second remaining amount L2 below the reference liquid level SP can be appropriately selected. In this case as well, after the pressure holding time has elapsed at the adjusted pressure, both storage chambers 71 and 76 are opened to the atmosphere, and the flow valves 48 and 49 are opened.

[0163] In the second embodiment, the pressurizing unit 62 only needs to pressurize at least the first storage chamber 71 of the two storage chambers 76. For example, the first storage chamber 71 may be pressurized, but the second storage chamber 76 may not be pressurized. In this case, when pressurizing the first storage chamber 71, the second on-off valve 87 may be closed to isolate the second storage chamber 76 from the atmosphere. If the possibility of the liquid level P3 overflowing is extremely low even without pressurizing the second storage chamber 76, and there are no problems with liquid transfer, then pressurizing the second storage chamber 76 is unnecessary.

[0164] - A valve can be provided in the outlet channel 41, and by closing the valve, the second storage chamber 76 may not be pressurized. In this way, pressurization is only required if at least the first storage chamber 71 of the two storage chambers 76 is pressurized.

[0165] The first threshold R1 is not limited to the near-end threshold; it may be a threshold specific to a different transfer mode than the near-end threshold. The first threshold R1 may also be greater than the near-end threshold. In this case, the transfer mode is executed earlier than the timing of liquid container 30 replacement, so the frequency of the amount of liquid remaining in the liquid container 30 at the time of replacement can be increased.

[0166] The second threshold R2 is not limited to the upper limit of the amount of liquid that can be stored in the liquid storage unit 40 (upper limit), but may also be a threshold specifically for the transfer mode. The third threshold is not limited to the same value as the second threshold (e.g., the upper limit); it may be a threshold even lower than the second threshold (e.g., the upper limit).

[0167] The detection unit for detecting the second remaining amount L2 is not limited to the first detection unit 43 and the second detection unit 44, which consist of physical sensors, but may also consist of soft sensors. The transfer mode may be executed immediately after detecting that the first remaining amount L1 has fallen below the first threshold R1 (for example, the near end). Also, if a print job has already been accepted when it is detected that the first remaining amount L1 has fallen below the first threshold (affirmative determination in step S11 or step S31), printing based on the print job may be prioritized.

[0168] The detection unit is not limited to being the same as the first detection unit 43 that detects the upper limit of the liquid volume (e.g., the overflow threshold), but may be a detection unit dedicated to the transfer mode. The second threshold R2 is not limited to the overflow threshold, and can be set to be suitable for the transfer mode. For example, if the second threshold R2 detected by the detection unit is set to a value smaller than the upper limit, it becomes easier to avoid overflow when the transfer mode is executed. This is effective, for example, when there is little margin in the upper limit.

[0169] Instead of the detection unit 43 consisting of physical sensors as shown in Figures 24 to 26, the detection of the second remaining amount L2 reaching the second threshold R2 may be performed by a detection unit 126 consisting of soft sensors. For example, this makes it easier to avoid overflow of the liquid storage unit 40 during transfer mode.

[0170] • Transport mode may be performed during printing or cleaning. The configuration may allow the liquid container 30 to be replaced during printing or cleaning. The liquid dispensing device 11 is not limited to a line printer; it may also be a serial printer.

[0171] The liquid dispensing device 11 may be a liquid dispensing device that dispenses liquids other than ink. The state of the liquid dispensed from the liquid dispensing device as minute droplets may include granular, teardrop-shaped, or thread-like forms. The liquid referred to here may be any material that can be dispensed from the liquid dispensing device. For example, the liquid may be any state in which a substance is in the liquid phase, and may include highly or low viscosity liquids, sols, gel water, other inorganic solvents, organic solvents, solutions, liquid resins, liquid metals, and other fluids. The liquid may include not only liquids as a state of matter, but also functional material particles consisting of solids such as pigments and metal particles dissolved, dispersed, or mixed in a solvent. Typical examples of liquids include inks and liquid crystals as described in the above embodiments. Here, ink refers to general water-based inks and oil-based inks, as well as various liquid compositions such as gel inks and hot-melt inks. Specific examples of liquid dispensing devices include devices that dispense liquids containing materials such as electrode materials and colorants in the form of dispersion or dissolution, used in the manufacture of liquid crystal displays, electroluminescent displays, surface-emitting displays, and color filters. Liquid dispensing devices may also be devices that dispense bio-organic substances used in biochip manufacturing, devices that dispense liquid samples used as precision pipettes, printing devices, microdispensers, etc. Liquid dispensing devices may also be devices that dispense lubricating oil to precision machinery such as watches and cameras with pinpoint accuracy, or devices that dispense transparent resin liquids such as ultraviolet-curing resins onto substrates to form minute hemispherical lenses, optical lenses, etc. used in optical communication elements. Liquid dispensing devices may also be devices that dispense etching solutions such as acids or alkalis to etch substrates.

[0172] [Definition] As used herein, the expression "at least one" means "one or more" of the desired options. For example, as used herein, if there are two options, the expression "at least one" means "only one option" or "both of the two options." As another example, as used herein, the expression "at least one" means "only one option," "a combination of two arbitrary options," or "a combination of three or more arbitrary options" if there are three or more options.

[0173] [Note] The technical concepts and their effects that can be understood from the embodiments and modifications described above are described below.

[0174] [1] The liquid dispensing device comprises a liquid dispensing unit capable of dispensing liquid, a liquid storage unit capable of storing liquid to be supplied to the liquid dispensing unit, a mounting unit to which a liquid container for containing liquid is attached, a transfer unit for transferring liquid from the liquid container to the liquid storage unit via the mounting unit, and a control unit. The control unit executes a transfer mode when the first remaining amount, which is the amount of liquid in the liquid container, falls below a first threshold, and transfers the liquid in the liquid storage unit to the liquid storage unit until the second remaining amount, which is the amount of liquid in the liquid storage unit, falls below a second threshold. After the transfer mode has been executed but before the liquid container is replaced, if the second remaining amount falls below a third threshold, which is a value smaller than the second threshold, the transfer mode is executed again.

[0175] With this configuration, after executing the transfer mode, if the remaining liquid in the second liquid reservoir becomes low, the transfer mode is executed again to transfer liquid to the liquid reservoir. Any liquid remaining in the liquid container that could not be transferred in one transfer mode can be reduced by further transfer. The amount of liquid remaining in the liquid container at the time of replacement can be further reduced. Therefore, by reducing the amount of liquid remaining when the liquid container is replaced, liquid waste can be suppressed.

[0176] [2] In the liquid dispensing device described in [1] above, the device is equipped with a detection unit for detecting when the first remaining amount of the liquid container has reached the end, and the control unit does not execute the transfer mode again if it detects that the first remaining amount has reached the end after the execution of the transfer mode, and does not execute the transfer mode again if it does not detect that the first remaining amount has reached the end after the execution of the transfer mode.

[0177] With this configuration, once the first remaining amount is reached during the transfer mode execution, there is no need to execute the transfer mode again. Therefore, unnecessary execution of the transfer mode can be avoided. For example, delays in starting liquid container replacement work or printing due to unnecessary delays can be avoided.

[0178] [3] In the liquid dispensing device described in [1] or [1] above, The system may also include a detection unit that physically detects when the second remaining quantity reaches the second threshold. With this configuration, the remaining quantity can be reliably managed because it is detected physically.

[0179] [4] In the liquid dispensing device described in [3] above, the detection unit also functions as an error detection unit that detects when the second remaining amount reaches the second threshold, and the control unit outputs the error when the detection unit detects that the second remaining amount has reached the second threshold, regardless of whether the transfer mode is executed, and does not need to output the error when the detection unit detects that the second remaining amount has reached the second threshold due to the execution of the transfer mode. With this configuration, in the transfer mode, no error is output when the second remaining amount reaches the second threshold, thus reducing user confusion.

[0180] [5] In the liquid dispensing device described in any one of [1] to [4] above, the control unit has a first acquisition unit that acquires the first remaining amount as a first estimated remaining amount, and a second acquisition unit that acquires the second remaining amount as a second estimated remaining amount, and when the transfer mode is executed, the first estimated remaining amount may be decreased by the amount of the estimated amount of liquid transferred in the transfer mode, and the second estimated remaining amount may be increased. With this configuration, the occurrence of a difference between the actual remaining amount and the estimated remaining amount can be suppressed. As a result, the amount of usable liquid can be appropriately managed.

[0181] [6] The liquid dispensing device described in [5] above may be provided with a display unit that displays information including at least one of the following after the transfer mode has been executed: the first estimated remaining amount, the second estimated remaining amount, and the usable estimated amount obtained by summing the first estimated remaining amount and the second estimated remaining amount. With this configuration, the user can individually configure the display settings, thereby improving usability.

[0182] [7] The liquid dispensing device described in [6] above may include an operating unit which is operated when selecting at least one of the options displayed on the display unit, and a setting unit which accepts and sets at least one of the first estimated remaining amount, the second estimated remaining amount, and the usable estimated amount to be displayed based on the selection made by the operating unit. With this configuration, the user can individually set the display, thus improving usability.

[0183] [8] In the liquid dispensing device described in any one of [1] to [7] above, a notification unit may be provided, and the control unit may cause the notification unit to notify the notification unit of information prompting the replacement of the liquid container when the first remaining amount falls below a first threshold. With this configuration, the user can know when it is time to replace the liquid container.

[0184] [9] In the liquid dispensing device described in any one of [1] to [8] above, a liquid supply unit is provided that supplies liquid from the liquid container to the liquid storage unit via the mounting unit when the liquid level of the liquid storage unit falls below a reference liquid level, and the transfer unit may transfer liquid by supplying liquid to the liquid supply unit even if the liquid level of the liquid storage unit is not below the reference liquid level. With this configuration, liquid can be transferred using the liquid supply unit.

[0185]

[10] In the liquid dispensing device described in any one of [1] to [8] above, the liquid dispensing device described in claim 1 is further provided with a liquid supply unit that supplies liquid from the liquid container to the liquid storage unit via the mounting unit when the liquid level in the liquid storage unit falls below a reference liquid level, and the transfer unit transfers liquid from the liquid container to the liquid storage unit via the mounting unit by adjusting the air pressure in the liquid storage unit to lower the liquid level to below the reference liquid level. With this configuration, the liquid can be transferred using the liquid supply unit by lowering the liquid level in the liquid storage unit to below the reference liquid level.

[0186]

[11] In a liquid discharge device described in any one of [1] to [8] above, the liquid storage unit comprises: a first storage chamber for storing liquid supplied from the liquid container via the mounting unit; a discharge channel connected at one end to the first storage chamber for discharging the liquid in the first storage chamber; a second storage chamber connected at the other end of the discharge channel for storing liquid supplied from the first storage chamber; and a one-way valve that restricts the direction in which the liquid flows through the discharge channel to one direction from the first storage chamber to the second storage chamber, wherein the first storage chamber The system further includes a liquid supply unit that supplies liquid from the liquid container to the liquid storage unit via the mounting unit when the liquid level falls below a reference liquid level, and the transfer unit has a depressurization unit that depressurizes the second storage chamber, a first atmospheric release unit that can open the first storage chamber to the atmosphere, and a second atmospheric release unit that can open the second storage chamber to the atmosphere, and the control unit may execute the transfer mode by depressurizing the second storage chamber with the transfer unit to bring the liquid level of the first storage chamber below the reference liquid level, and then opening the second storage chamber to the atmosphere. With this configuration, the transfer mode can be executed by depressurizing even if the liquid supply unit does not have a liquid supply means such as a pump, thus simplifying the flow path configuration and suppressing waste of liquid remaining in the liquid container that is not used.

[0187]

[12] In the liquid discharge device described in any one of [1] to [8] above, the liquid storage unit has: a first storage chamber for storing liquid supplied from the liquid container via the mounting unit; a discharge channel connected at one end to the first storage chamber for discharging the liquid in the first storage chamber; a second storage chamber connected at the other end of the discharge channel for storing liquid supplied from the first storage chamber; and a one-way valve that restricts the direction in which the liquid flows through the discharge channel to one direction from the first storage chamber to the second storage chamber, wherein when the liquid level in the first storage chamber falls below the reference liquid level, the liquid container The transfer unit further comprises a liquid supply unit for supplying liquid to the first storage chamber via the mounting unit, and the transfer unit has a pressurizing unit for pressurizing at least the first storage chamber among the first and second storage chambers, a first atmospheric release unit that can open the first storage chamber to the atmosphere, and a second atmospheric release unit that can open the second storage chamber to the atmosphere, and the control unit may execute the transfer mode by pressurizing at least the first storage chamber with the transfer unit to bring the liquid level of the first storage chamber below the reference liquid level, and then opening the pressurized at least the first storage chamber to the atmosphere.

[0188] With this configuration, the liquid transfer mode can be performed by pressurizing the first storage chamber, even if the liquid supply unit does not have a liquid delivery means such as a pump. Therefore, the flow path configuration can be simplified while suppressing waste of liquid remaining in the liquid container that is not used.

[0189]

[13] A liquid dispensing device according to any one of [1] to

[12] above may include a supply channel for supplying liquid from the liquid storage section toward the liquid dispensing section, and a recovery channel for recovering liquid from the liquid dispensing section toward the liquid storage section. With this configuration, the amount of liquid that can be held on the device side can be increased by the length of the channel for circulating the liquid, while suppressing the thickening of the liquid and recovering foreign matter such as bubbles in the liquid by circulating the liquid.

[0190]

[14] A control method for a liquid dispensing device, comprising: a liquid dispensing unit capable of dispensing liquid; a liquid storage unit capable of storing liquid to be supplied to the liquid dispensing unit; a mounting unit to which a liquid container for storing liquid is attached; and a transfer unit for transferring liquid from the liquid container to the liquid storage unit via the mounting unit, wherein when the first remaining amount, which is the amount of liquid in the liquid container, falls below a first threshold, a transfer mode is executed to transfer the liquid in the liquid container to the liquid storage unit until the second remaining amount, which is the amount of liquid in the liquid storage unit, falls below a second threshold; and after the execution of the transfer mode and before the liquid container is replaced, when the second remaining amount falls below a third threshold, which is a value smaller than the second threshold, the transfer mode is executed again.

[0191] According to this method, after executing the transfer mode, the transfer mode is executed again when the second remaining amount in the liquid storage section decreases, thereby repeatedly transferring the liquid. This reduces the amount of liquid remaining when the liquid container is replaced, thus minimizing liquid waste. [Explanation of Symbols]

[0192] 11…Liquid dispensing device, 12…Device body, 12A…Recess, 13…Image reading unit, 13A…Reading unit, 13B…Automatic document feeding unit, 13C…Document tray, 13D…Output tray, 14…Media storage unit, 15…Media placement unit, 16…Stacker, 16A…Output tray, 17…Display unit, 18…Operation unit, 18A…Power switch, 19…Cover, 19A…Window, 20…Liquid dispensing unit, 21…Dispensing head, 21A…Nozzle opening surface, 21N…Nozzle, 22…Liquid supply unit, 23…Circulation channel, 25…Maintenance unit, 26…Cap, 28…Transport unit, 30…Liquid container, 31…Container body Body (main unit), 31A...Window section, 31P...Liquid pack, 32...Supply section, 33...Memory element, 34...Valve body, 35...Valve seat, 36...Spring, 40...Liquid storage section, 41...Outlet channel, 42...One-way valve, 43...Detection section (first detection section), 44...Detection section (second detection section), 45...Electrode type sensor, 45A...Upper limit electrode, 45B...Lower limit electrode, 45C...Reference electrode, 46...Supply channel, 47...Recovery channel, 48...First channel valve, 49...Second channel valve, 50...Mounting section, 51...Supplied section, 52...Case, 53...Connection terminal, 54...Connected section, 55...Communication passage, 56...Liquid replenishment section, 57...Gas-liquid exchange section, 58...Replenishment Flow path, 59...partition wall section, 59A...lower end, 60...transfer section, 61...depressurization section, 62...pressurization section, 63...atmospheric vent section, 63A...first atmospheric vent section, 63B...second atmospheric vent section, 64...depressurization pump, 65...pressurization pump, 70...first storage section, 71...first storage chamber, 72...first housing, 73...air chamber, 74...moisture-permeable membrane, 75...second storage section, 76...second storage chamber, 77...second housing, 78...air chamber, 79...moisture-permeable membrane, 80...selector valve, 81...pressure switching mechanism, 81A...depressurization flow path, 81B...pressurization flow path, 81C...atmospheric flow path, 81D...detection flow path, 82...on-off valve, 83...on-off valve, 84 ...Atmospheric release valve, 85...Pressure sensor, 86...First on / off valve, 87...Second on / off valve, 88...First air passage, 89...Second air passage, 90...Detection unit (first detection unit), 91...Prism, 92...Optical sensor, 93...First surface, 94...Second surface, 95...Third surface, 96...Light emitting unit, 97...Light receiving unit, 98...Second detection unit, 100...Control unit, 101...Communication interface, 110...Computer, 111...CPU, 112...Storage unit, 121...Liquid consumption counting unit, 122...First acquisition unit, 123...Detection unit, 124...Transfer control unit, 125...Second acquisition unit, 126...Detection unit, 127...Setting unit,128...Notification processing unit, 130...Liquid volume display setting screen (setting screen), 131...Options, 132...Options, 133...Options, 134...OK button, 135...Cancel button, 136...Notification screen, 137...Liquid volume information notification screen, 141...Storage chamber, 150...Replenishment channel, 151...Pump, 152...Pump, 153...Pump, 160...Liquid storage section, 161...Liquid chamber, 162...Flexible section, 163...Air chamber, 164...Spring, 165...Air channel, D...Original document, M...Media, B1...Air bubble, L1...First remaining volume ( (Value of the first estimated remaining amount), L2...Second remaining amount (Value of the second estimated remaining amount), MS1...Message, MS2...Message, MS11...Message, MS12...Message, MS13...Message, N...Number of transfer mode executions, P1...Liquid level, P2...Liquid level, P3...Liquid level, Pn...Pressure, Pa...Pressure, R1...First threshold, R2...Second threshold, R3...Third threshold, RE...End threshold, SP...Reference liquid level, T1...Depressurization time, T2...Pressurization time, PD...Print data, PR...Program, RD...Remaining amount data, X...Width direction.

Claims

1. A liquid dispensing unit capable of dispensing liquid, A liquid storage section capable of storing the liquid supplied to the liquid discharge section, A mounting section to which a liquid container that holds liquid is attached, A transfer unit that transfers liquid from the liquid container to the liquid storage unit via the mounting portion, It comprises a control unit and, The control unit, When the first remaining amount, which is the amount of liquid in the liquid container, falls below the first threshold, a transfer mode is executed to transfer the liquid in the liquid container to the liquid storage section until the second remaining amount, which is the amount of liquid in the liquid storage section, reaches the second threshold. A liquid dispensing device characterized in that, after the transfer mode has been executed but before the liquid container has been replaced, if the second remaining amount falls below a third threshold value which is smaller than the second threshold value, the transfer mode is executed again.

2. In the liquid dispensing device according to claim 1, The system includes a detection unit that detects when the first remaining amount of the liquid container has reached its end. The control unit, If it is detected that the first remaining quantity has reached its end after the execution of the transfer mode, the transfer mode will not be executed again. A liquid dispensing device characterized in that, if it is not detected that the first remaining amount has reached the end after the execution of the transfer mode, the transfer mode is executed again.

3. In the liquid dispensing device according to claim 1, A liquid dispensing device characterized by comprising a detection unit that physically detects when the second remaining amount reaches the second threshold.

4. In the liquid dispensing device according to claim 3, The detection unit also functions as an error detection unit that detects when the second remaining amount reaches the second threshold as an error. The control unit, Regardless of the execution of the transfer mode, if the detection unit detects that the second remaining amount has reached the second threshold, it outputs the error. A liquid dispensing device characterized in that, if the detection unit detects that the second remaining amount has reached the second threshold due to the execution of the transfer mode, it does not output the error.

5. In the liquid dispensing device according to claim 1, The control unit, A first acquisition unit that acquires the first remaining amount as the first estimated remaining amount, It includes a second acquisition unit that acquires the second remaining amount as a second estimated remaining amount, A liquid dispensing device characterized in that, when the transfer mode is executed, the first estimated remaining amount is reduced by the estimated amount of liquid transferred in the transfer mode, and the second estimated remaining amount is increased.

6. In the liquid dispensing device according to claim 5, After the execution of the aforementioned transport mode, A liquid dispensing device characterized by having a display unit that displays information including at least one of the following: the first estimated remaining amount, the second estimated remaining amount, and the usable estimated amount obtained by summing the first estimated remaining amount and the second estimated remaining amount.

7. In the liquid dispensing device according to claim 6, An operating unit which is operated when selecting at least one of the options displayed on the aforementioned display unit, A liquid dispensing device comprising a setting unit that accepts and sets at least one of the first estimated remaining amount, the second estimated remaining amount, and the usable estimated amount to be displayed, based on a selection made by the operation of the control unit.

8. In the liquid dispensing device according to claim 1, Equipped with a news department, The control unit, A liquid dispensing device characterized in that when the remaining amount of the first liquid falls below a first threshold, the notification unit notifies the notification unit of information prompting the replacement of the liquid container.

9. In the liquid dispensing device according to claim 1, A liquid supply unit is provided to supply liquid to the liquid storage unit from the liquid container via the mounting unit when the liquid level in the liquid storage unit falls below a reference liquid level. The liquid dispensing device is characterized in that the transfer unit transfers liquid by supplying liquid to the liquid supply unit, even if the liquid level in the liquid storage unit is not below the reference liquid level.

10. In the liquid dispensing device according to claim 1, A liquid supply unit is provided to supply liquid to the liquid storage unit from the liquid container via the mounting unit when the liquid level in the liquid storage unit falls below a reference liquid level. The liquid dispensing device is characterized in that the transfer unit adjusts the air pressure in the liquid storage unit to lower the liquid level to below the reference liquid level, thereby transferring liquid from the liquid container to the liquid storage unit via the mounting unit.

11. In the liquid dispensing device according to claim 1, The liquid storage section is, A first storage chamber for storing the liquid supplied from the liquid container via the mounting portion, A discharge channel, one end of which is connected to the first storage chamber, discharges the liquid from the first storage chamber, A second storage chamber is connected to the other end of the aforementioned outlet channel and stores the liquid supplied from the first storage chamber, It includes a one-way valve that restricts the direction in which the liquid flows through the aforementioned outlet channel to one direction from the first storage chamber to the second storage chamber, The system further includes a liquid supply unit that supplies liquid to the liquid storage chamber from the liquid container via the mounting unit when the liquid level in the first storage chamber falls below a reference liquid level. The transfer unit is A depressurization unit for reducing the pressure in the second storage chamber, A first atmospheric vent that allows the first storage chamber to be opened to the atmosphere, The second storage chamber has a second atmospheric vent that allows the chamber to be opened to the atmosphere, The liquid dispensing device is characterized in that the control unit performs the transfer mode by reducing the pressure inside the second storage chamber in the transfer unit to bring the liquid level in the first storage chamber below the reference liquid level, and then opening the second storage chamber to the atmosphere.

12. In the liquid dispensing device according to claim 1, The liquid storage section is, A first storage chamber for storing the liquid supplied from the liquid container via the mounting portion, A discharge channel, one end of which is connected to the first storage chamber, discharges the liquid from the first storage chamber, A second storage chamber is connected to the other end of the aforementioned outlet channel and stores the liquid supplied from the first storage chamber, It includes a one-way valve that restricts the direction in which the liquid flows through the aforementioned outlet channel to one direction from the first storage chamber to the second storage chamber, The system further includes a liquid supply unit that supplies liquid from the liquid container to the first storage chamber via the mounting unit when the liquid level in the first storage chamber falls below a reference liquid level. The transfer unit is A pressurizing unit that pressurizes at least the first storage chamber among the first and second storage chambers, A first atmospheric vent that allows the first storage chamber to be opened to the atmosphere, The second storage chamber has a second atmospheric vent that allows the chamber to be opened to the atmosphere, The liquid dispensing device is characterized in that the control unit pressurizes at least the first storage chamber in the transfer unit to bring the liquid level in the first storage chamber below the reference liquid level, and then opens the pressurized at least the first storage chamber to the atmosphere to execute the transfer mode.

13. In the liquid dispensing device according to claim 1, A supply channel for supplying liquid from the liquid storage section toward the liquid discharge section, A liquid dispensing device characterized by comprising a recovery channel for recovering liquid from the liquid dispensing section to the liquid storage section.

14. A liquid dispensing unit capable of dispensing liquid, A liquid storage section capable of storing the liquid supplied to the liquid discharge section, A mounting section to which a liquid container that holds liquid is attached, A control method for a liquid dispensing device comprising: a transfer unit that transfers liquid from the liquid container to the liquid storage unit via the mounting unit; When the first remaining amount, which is the amount of liquid in the liquid container, falls below the first threshold, a transfer mode is executed to transfer the liquid in the liquid container to the liquid storage section until the second remaining amount, which is the amount of liquid in the liquid storage section, reaches the second threshold. A control method for a liquid dispensing device, characterized in that, after the transfer mode has been executed but before the liquid container has been replaced, if the second remaining amount falls below a third threshold value which is smaller than the second threshold value, the transfer mode is executed again.

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