Liquid dispensing device

Abstract

To provide a liquid discharge device that can suppress liquid from leaking from a connection portion of a joint part of a supply passage, when the joint part is detached from a liquid discharge head.SOLUTION: A liquid discharge device comprises a liquid discharge head that can discharge liquid. The liquid discharge device comprises a storage part configured to be able to store liquid which is supplied to the liquid discharge head. The storage part is provided at a position lower than the liquid discharge head. The liquid discharge device comprises a supply passage 87 through which the liquid discharge head can be communicated with the storage part. The supply passage 87 is provided with a joint part 88 that can be attached to and detached from the liquid discharge head. The liquid discharge device comprises a holding part 90 that can hold the joint part 88 detached from the liquid discharge head. The joint part 88 has a connection portion 89 that is connected to the liquid discharge head. The holding part 90 is configured to be able to hold the joint part 88 while pointing the connection portion 89 upward.SELECTED DRAWING: Figure 5

Description

Technical Field

[0001] The present invention relates to a liquid ejection device including a liquid ejection head that ejects a liquid supplied from a storage unit in which the liquid is stored.

Background Art

[0002] Patent Document 1 discloses an inkjet printer as an example of a liquid ejection device including a liquid ejection head that ejects a liquid such as ink. This type of liquid ejection device includes a storage unit that stores a liquid. The storage unit and the liquid ejection head are connected through a supply flow path. The liquid ejection head prints on a medium by ejecting the liquid supplied from the storage unit through the supply flow path.

[0003] In the liquid ejection device described in Patent Document 1, the liquid ejection head is replaceable. The liquid ejection device includes a joint portion at the tip of a supply flow path extending from the storage unit. The connection portion of the joint portion is detachably connected to a connection portion provided on the liquid ejection head. When the liquid ejection head is replaced, the joint portion is removed from the liquid ejection head.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, in the liquid ejection device described in Patent Document 1, the joint portion removed from the liquid ejection head is held by the holding portion with the connection portion facing in the horizontal direction, and the supply flow path is held. Therefore, there is a risk that a liquid such as ink drips from the connection portion of the joint portion. This dripping of the liquid may stain components or the like below the device body of the liquid ejection device or the joint portion. Although dripping of the liquid from the joint portion can be suppressed by once emptying the liquid in the storage unit, an extra operation of emptying the storage unit is required. [Means for solving the problem]

[0006] A liquid dispensing device that solves the above problems comprises a liquid dispensing head capable of dispensing liquid, a storage section provided at a lower position than the liquid dispensing head and capable of storing liquid to be supplied to the liquid dispensing head, a supply channel provided with a joint that can be attached to and detached from the liquid dispensing head and capable of communicating the liquid dispensing head and the storage section, and a holding section capable of holding the joint when it has been removed from the liquid dispensing head, wherein the joint has a connecting portion that is connected to the liquid dispensing head, and the holding section is configured to hold the joint with the connecting portion facing upward. [Brief explanation of the drawing]

[0007] [Figure 1] This is a perspective view showing the liquid dispensing device in the first embodiment. [Figure 2] This is a schematic cross-sectional view showing the internal structure of a liquid dispensing device. [Figure 3] This is a schematic cross-sectional view illustrating the movement mechanism of the liquid dispensing head. [Figure 4] This is a schematic front view illustrating the configuration involved in the replacement of the liquid dispensing head. [Figure 5] This is a schematic front view showing the joint section placed on the retaining section. [Figure 6] This is a schematic diagram of the liquid supply unit. [Figure 7] This is a schematic cross-sectional view showing a variable capacitance mechanism in its initial state. [Figure 8] This is a schematic cross-sectional view showing a variable-volume mechanism in a state where liquid has been drawn in. [Figure 9] This is a flowchart showing the drip suppression control routine. [Figure 10] This is a flowchart showing the drip suppression control routine in the second embodiment. [Modes for carrying out the invention]

[0008] (First Embodiment) The first embodiment of the liquid dispensing device will be described below with reference to the drawings. The liquid dispensing device is, for example, an inkjet printer that prints by dispensing ink, which is an example of a liquid, onto a medium such as paper.

[0009] In the drawing, the direction of gravity is indicated by the Z-axis, assuming the liquid dispensing device 11 is placed on a horizontal plane, and the directions along the horizontal plane are indicated by the X-axis and Y-axis. The X-axis, Y-axis, and Z-axis are orthogonal to each other. The X-axis indicates the depth direction of the liquid dispensing device 11, and the Y-axis indicates the width direction of the liquid dispensing device 11. The direction parallel to the X-axis is also the width direction of the medium M, so it is sometimes referred to as the width direction X.

[0010] <Overall configuration of the liquid dispensing device> As shown in Figure 1, the liquid ejection device 11 is, for example, a multifunction printer. The liquid ejection device 11 comprises a rectangular parallelepiped-shaped device body 12. The device body 12 constitutes an inkjet printer. In this example, where the liquid ejection device 11 is a multifunction printer, an image reading unit 13 is provided on the upper part of the device body 12.

[0011] 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.

[0012] 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. In this case, the media storage section 14 may be provided in one or more stages (for example, four stages in Figure 1). If it is a cassette, 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 may accommodate, for example, media M of different sizes or types. In addition to the media storage section 14, the liquid dispensing device 11 may also include a media mounting section 14A, such as a paper feed tray, on which media M can be placed, as a media supply section.

[0013] As shown in Figure 1, the main body of the device 12 has a liquid ejection head 20 capable of ejecting liquid. The liquid ejection head 20 prints images, etc., on the medium M supplied from the medium storage unit 14 by ejecting ink, which is an example of a liquid, onto the medium M. Inside the main body of the device 12 is a liquid container 82 (see Figure 2) that contains ink, which is an example of a liquid. The liquid ejection head 20 prints on the medium M using a liquid such as ink supplied from the liquid container 82. The liquid ejection device 11 of this embodiment allows for the replacement of the liquid ejection head 20. Details of the liquid ejection head 20 replacement procedure will be described later.

[0014] The liquid dispensing device 11 includes a stacker 18 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 18 consists of the recess 12A and a discharge tray 18A attached to the bottom of the recess 12A. The discharge tray 18A is a rectangular plate-shaped member. In this embodiment, the discharge tray 18A is attached to the device body 12 in a detachable manner. The printed media M discharged from the device body 12 into the recess 12A is stacked on the upper surface (stacking surface) of the discharge tray 18A. The discharge tray 18A is inclined at a predetermined angle such that the downstream side in the discharge direction from which the printed media M is discharged is higher than the upstream side.

[0015] The liquid ejection device 11 may have a display unit 19 on the device main body 12. The display unit 19 is, for example, a touch panel. An operation unit 19A may be configured by the touch operation function of the display unit 19. The user can give an instruction to the liquid ejection device 11 by operating the operation unit 19A. Further, the liquid ejection device 11 includes a power button 19B that is operated to turn on / off the power. Note that the operation unit 19A may be an operation button provided separately from the display unit 19.

[0016] The liquid ejection device 11 includes a control unit 100 that controls the entire device. The control unit 100 performs a plurality of types of control including printing control for controlling a printing mechanism including the liquid ejection head 20, reading control for controlling the image reading unit 13, and display control for controlling the display unit 19. The control unit 100 includes a computer (not shown). The computer includes a CPU (Central Processing Unit) and a memory (not shown). The CPU is an arithmetic processing unit. The memory is a storage device that secures an area for storing the program of the CPU or a work area, etc., and has storage elements such as RAM (Random Access Memory) and EEPROM (Electrically Erasable Programmable Read-Only Memory), and a storage, etc. The CPU controls the operations of each part of the liquid ejection device 11 according to the program stored in the memory.

[0017] In the liquid ejection device 11 of the present embodiment, it is possible to replace the liquid ejection head 20 by an operator such as a service technician or a user. The operator operates the operation unit 19A on the menu screen displayed on the display unit 19 to select the service mode, and further selects the head replacement.

[0018] When the control unit 100 receives a signal indicating that the service mode has been instructed, it shifts from the printing mode to the service mode. When the control unit 100 receives a head replacement command in the service mode, it moves the liquid ejection head 20 from its current position (e.g., the cap position) to the replacement position PH2 (see FIG. 3) below the discharge tray 18A. By the operator removing the discharge tray 18A, it becomes possible to remove the liquid ejection head 20 from the apparatus main body 12. Note that the operator may, after the liquid ejection head 20 has moved to the replacement position PH2, operate the power button 19B to turn off the power and perform the head replacement operation in this power-off state. Also, there may be cases where the liquid ejection head 20 is removed from the apparatus main body 12 for the purpose of investigating the cause of a failure or performing maintenance.

[0019] <Regarding the internal configuration of the liquid ejection apparatus 11>[[ID=)5]] Next, the internal configuration of the liquid ejection apparatus 11 will be described with reference to FIG. 2. As shown in FIG. 2, the medium storage unit 14 can store a plurality of media M in a stacked state. The liquid ejection apparatus 11 includes a feeding unit 15 that feeds the medium M from the medium storage unit 14, and a conveying unit 17 that conveys the medium M along a conveying path 16 indicated by a one-dot chain line in FIG. 2. The conveying path 16 is a path that connects the medium storage unit 14 and the stacker 18.

[0020] The feeding unit 15 may include a feeding roller 23 that feeds the medium M stored in the medium storage unit 14, and a separating unit 24 that separates the media M one by one. The feeding unit 15 sends out the medium M stored in the medium storage unit 14 to the conveying path 16.

[0021] The conveying unit 17 may include a conveying roller 26, an endless conveying belt 27, and a pair of rollers 28 around which the conveying belt 27 is looped. The conveying unit 17 may include a plurality of conveying rollers 26. The conveying roller 26 conveys the medium M by rotating while sandwiching the medium M.

[0022] The conveyor belt 27 has a conveying surface 27a for conveying the medium M. The conveying surface 27a is a plane on the outer circumferential surface of the conveyor belt 27 that supports the medium M, for example, by electrostatic attraction. The conveyor belt 27 may be provided with the conveying surface 27a inclined with respect to the horizontal plane. In this embodiment, the direction along the conveying surface 27a that conveys the medium M is called the conveying direction Dc. The conveyor belt 27 conveys the medium M in the conveying direction Dc by circulating with the medium M supported on the conveying surface 27a.

[0023] The liquid discharge head 20 has a nozzle surface 21A through which a nozzle 21N for discharging liquid opens. The liquid discharge head 20 prints onto the medium M supported on the conveying surface 27a of the conveying belt 27 by discharging liquid from the nozzle 21N. The liquid discharge head 20 in this embodiment is a line type capable of discharging liquid over the width direction X of the medium M. The liquid discharge head 20 is mounted so that its longitudinal direction coincides with the width direction X of the medium M.

[0024] As shown in Figure 2, the liquid dispensing device 11 includes a liquid supply unit 80 capable of supplying liquid to the liquid dispensing head 20. The liquid dispensing device 11 includes a frame 12C that houses the liquid dispensing head 20 and the liquid supply unit 80. The frame 12C has an opening HL through which the liquid supply unit 80 can pass in the depth direction X.

[0025] The liquid supply unit 80 comprises a liquid supply section 81, a supply channel 87, and a connector section 88 provided at the tip of the supply channel 87. The connector section 88 is connected to a connection section 22 provided on the liquid discharge head 20.

[0026] The liquid supply unit 81 includes a mounting section 83 to which a liquid container 82 containing liquid is detachably attached. The mounting section 83 has a needle portion 84. The liquid container 82 attached to the mounting section 83 becomes capable of supplying liquid when inserted into the needle portion 84. The liquid supply unit 81 includes a supply mechanism 85 that stores the liquid supplied from the liquid container 82 via the mounting section 83 and can supply the stored liquid to the liquid discharge head 20 through a supply channel 87.

[0027] The liquid dispensing device 11 includes a storage section 86 configured to store the liquid supplied to the liquid dispensing head 20. In this embodiment, the storage section 86 is provided in the supply mechanism 85 and stores the liquid supplied from the liquid container 82 via the mounting section 83. In this respect, the liquid container 82 in this example stores the liquid supplied to the storage section 86.

[0028] The storage section 86 is located at a lower position than the liquid discharge head 20. In this example, the liquid discharge head 20 is configured to move along a movement path that passes through the printing position PH1 and the replacement position PH2 (see Figure 3), which have different height positions in the vertical Z direction. When the liquid discharge head 20 is at the printing position PH1, which is the lowest position on the movement path as shown in Figure 2, the liquid level in the storage section 86 is lower than the position of the nozzle surface 21A of the liquid discharge head 20.

[0029] The liquid dispensing device 11 includes a supply channel 87 that can connect the liquid dispensing head 20 and the storage section 86. The supply channel 87 is provided with a joint 88 that can be attached to and detached from the liquid dispensing head 20.

[0030] The supply channel 87 has one end connected to the supply mechanism 85 and the other end connected to the joint 88. The supply channel 87 is connected at one end to the storage section 86 that constitutes the supply mechanism 85. There are as many storage sections 86 as there are types of liquids discharged by the liquid discharge head 20.

[0031] Multiple liquid containers 82 may each contain a different type of liquid. For example, multiple liquid containers 82 may contain inks of different colors. For example, multiple liquid containers 82 may contain cyan, magenta, yellow, and black inks. Multiple liquid containers 82 may contain different amounts of liquid. For example, a liquid container 82 containing black ink may contain a larger amount of liquid than liquid containers 82 containing inks of other colors.

[0032] The liquids contained in the multiple liquid containers 82 are supplied to the multiple corresponding storage units 86 via the mounting unit 83. Different types of liquids are stored in the multiple storage units 86. A supply channel 87 is provided for each type of liquid supplied from the multiple storage units 86 to the liquid discharge head 20.

[0033] The supply channel 87 is configured such that a variable section 87A, which extends for a predetermined length from the joint section 88, is deformable. The supply channel 87 may also have a fixed section 87B that extends from the storage section 86 to the variable section 87A and is held in a state where it is difficult to deform. The fixed section 87B of the supply channel 87 may be a communication hole formed as a channel in a channel member made of synthetic resin, or it may be a tube held by a guide member. The variable section 87A of the supply channel 87 is made of a flexible material, for example, a channel made of elastic synthetic resin or rubber. The variable section 87A of the supply channel 87 may be, for example, a tube. Note that the supply channel 87 only needs to have at least a part of it as a deformable variable section 87A, and may be entirely a variable section 87A. Furthermore, the variable section 87A is not limited to a flexible tube, but may also be a bellows or the like.

[0034] The liquid discharge head 20 has a connected portion 22 to which a fitting portion 88 is detachably connected. When the fitting portion 88 is connected to the connected portion 22, the storage portion 86 and the liquid discharge head 20 are connected through the supply channel 87.

[0035] A single joint 88 may connect multiple supply channels 87 to the liquid discharge head 20. Alternatively, the number of joints 88 may be equal to the number of supply channels 87. In the following explanation, a configuration in which a single joint 88 connects multiple supply channels 87 to the liquid discharge head 20 will be used as an example.

[0036] As shown in Figure 2, the liquid dispensing device 11 includes a holding portion 90 capable of holding the joint portion 88 removed from the liquid dispensing head 20. The holding portion 90 is located below the discharge tray 18A. The holding portion 90 is positioned so that it is exposed through the opening 12D when the discharge tray 18A is removed during head replacement. In the example shown in Figure 2, the holding portion 90 is fixed to the upper surface of a frame portion 12F, which has a horizontal surface located above the area where the multiple liquid containers 82 are arranged in the frame 12C. The configuration of the liquid dispensing device 11, including the holding portion 90 provided for head replacement, will be described later.

[0037] In the liquid supply unit 81, the mounting section 83 and a portion of the supply channel 87 are located behind the opening HL in the depth direction X. Therefore, when an operator views the opening HL from a position in front of the frame 12C, they can see a portion of the storage unit 86 through the opening HL. The storage unit 86 has a transparent synthetic resin window on the front in Figure 2, allowing the user to visually check the remaining amount of liquid in the storage unit 86 through the window.

[0038] The liquid dispensing device 11 includes a maintenance unit 95 for performing maintenance on the liquid dispensing head 20. The liquid dispensing device 11 also includes a waste liquid container 97 for collecting the liquid discharged from the liquid dispensing head 20 during maintenance. The maintenance unit 95 is connected to the waste liquid container 97 via a pump (not shown) and a waste liquid flow path that sends the liquid discharged from the liquid dispensing head 20 during maintenance to the waste liquid container 97. Both ends of the waste liquid flow path are connected to the maintenance unit 95 and the needle portion 98 of the waste liquid container 97. The liquid dispensing device 11 also includes a supply mechanism 85 and a tray 99 on which the waste liquid container 97 is placed. The tray 99 contains a liquid absorbent member (not shown) capable of absorbing liquid.

[0039] <Movement mechanism of liquid discharge head 20> Next, the movement mechanism of the liquid discharge head 20 will be described with reference to Figure 3. As shown in Figure 3, the liquid discharge head 20 is movable in direction B, which is the direction opposite to the transport surface 27a. Direction B may be a direction inclined by a predetermined angle with respect to the horizontal plane. The liquid discharge device 11 is equipped with a guide rail 101 that guides the liquid discharge head 20 so that it can move in direction B. The liquid discharge head 20 is equipped with guide rollers 20R that engage with the guide rail 101. The liquid discharge head 20 moves in direction B as the multiple guide rollers 20R are guided by the guide rail 101.

[0040] As shown in Figure 3, the liquid dispensing device 11 includes a moving mechanism 110 that moves the liquid dispensing head 20 in the B direction. The moving mechanism 110 is, for example, a rack and pinion mechanism. The moving mechanism 110 is composed of, for example, a rack 111 and a drive gear 112. The drive gear 112 is driven by the power of a motor 113, which is the power source for the moving mechanism 110. When the motor 113 is driven in the forward direction, the liquid dispensing head 20 moves in the +B direction. On the other hand, when the motor 113 is driven in the reverse direction, the liquid dispensing head 20 moves in the -B direction. By moving in the direction of movement (±B direction), the liquid dispensing head 20 is positioned at the printing position PH1 (Figure 2) and the replacement position PH2.

[0041] The printing position PH1 is the position of the liquid ejection head 20 when printing on the medium M. The replacement position PH2 is the position when replacing the liquid ejection head 20. As shown in Figure 3, the liquid ejection device 11 is equipped with replacement guide rails 102 and 103 for removing and attaching the liquid ejection head 20 to the device body 12 at the replacement position PH2. In addition, there are other stopping positions for the liquid ejection head 20 along the movement path between the printing position PH1 and the replacement position PH2, namely the cap position and the retracted position.

[0042] The maintenance unit 95 shown in Figure 3 has a cap unit 115 having a cap 116. The cap 116 can contact the nozzle surface 21A of the head unit 21 and cover the nozzle 21N by capping.

[0043] As shown in Figure 3, the liquid dispensing device 11 includes a moving mechanism 120 that moves the cap unit 115 in direction A, which intersects (for example, is perpendicular to) direction B, which is the direction of movement of the liquid dispensing head 20. The moving mechanism 120 is, for example, a rack and pinion mechanism and includes a rack 121, a drive gear 122, and a motor 123. When the motor 123 is driven forward, the cap unit 115 moves in the +A direction, and when the motor 123 is driven backward, it moves in the -A direction. When the cap unit 115 is positioned in the capping position shown in Figure 3, where the cap 116 faces the head portion 21, the liquid dispensing head 20 moves from the retracted position in the +B direction, and the liquid dispensing head 20 is capped. In the capped state, a substantially closed space communicating with the nozzle 21N is formed between the nozzle surface 21A and the cap 116, thereby suppressing the drying of the liquid inside the nozzle 21N. Furthermore, under capping conditions, the nozzle 21N of the head unit 21 is forcibly discharged into the cap 116, thereby cleaning the nozzle 21N. This cleaning process forcibly discharges the liquid inside the nozzle 21N along with thickened ink and air bubbles, preventing or resolving dispensing problems in the liquid discharge head 20.

[0044] As shown in Figure 3, during head replacement, the liquid discharge head 20 moves along the guide rail 101, for example, from the cap position to the replacement position PH2. When the liquid discharge head 20 is at the replacement position PH2, the guide roller 20R moves vertically in the Z direction along the two guide rails 102 and 103, allowing it to be removed from and attached to the device body 12. At the replacement position PH2, the liquid discharge head 20 is removed from the device body 12 by being pulled upward along the guide rails 102 and 103 by an operator.

[0045] When an operator replaces the liquid discharge head 20, they use the control unit 19A to instruct the operator to replace the head, and the control unit 100 reverses the motor 113 to move the liquid discharge head 20 to the replacement position PH2. With the discharge tray 18A removed, the operator removes the joint 88 from the liquid discharge head 20 through the opening 12D. Next, the liquid discharge head 20 is removed from the device body 12 as shown by the dashed line in Figure 3.

[0046] During printing, valves 38 and 40 (see Figure 6), which can open and close the supply channel 87 connecting the storage unit 86 and the liquid discharge head 20, are in the open state, and the liquid supplied from the storage unit 86 is discharged from the liquid discharge head 20. When not printing, valves 38 and 40 are in the closed state. Thus, when not printing, since valves 38 and 40 are closed, if the following disturbances occur during head replacement, liquid may drip from the joint 88 removed from the liquid discharge head 20. Examples of disturbances (causes) that may cause liquid to drip from the joint 88 are as follows. (a) The worker presses on the tube of the supply channel 87 during the head replacement work. (b) Acceleration or impact is applied when removing the joint 88 from the liquid discharge head 20. (c) Air bubbles are present inside the tube of the supply channel 87. In (c), the air bubbles reduce the holding pressure, which is a negative pressure acting in a direction that prevents liquid from dripping from the joint 88.

[0047] In this embodiment, from two perspectives, the liquid dripping from the joint 88 due to any of the above (a) to (c) is prevented or reduced from contaminating the inside of the device body 12. <Perspective 1> Even if liquid spills, it will not contaminate the inside of the device. <Perspective 2> Prevent or reduce liquid dripping.

[0048] Furthermore, even when removing the liquid discharge head 20 from the main body 12 while the joint 88 and the liquid discharge head 20 are connected, if the above-mentioned disturbance occurs, liquid may drip from the nozzle 21N of the liquid discharge head 20. From this point of view, points 1 and 2 also serve as points for suppressing liquid dripping from the nozzle 21N of the liquid discharge head 20 when the joint 88 and the liquid discharge head 20 are connected.

[0049] First, the configuration adopted from viewpoint 1 will be described with reference to Figures 2, 4, and 5. As shown in Figure 4, the joint portion 88 has a connecting portion 89 that is connected to the liquid discharge head 20. The liquid discharge head 20 has a connected portion 22 that can be connected to the connecting portion 89 of the joint portion 88. When the connecting portion 89 of the joint portion 88 and the connected portion 22 are connected, at least a portion of the supply flow path 87 passes over the mounting portion 83 and is connected to the liquid discharge head 20.

[0050] The connection section 89 has the same number of pipe sections 89A as the number of supply passages 87. The supply passage 87 constitutes part of the circulation passage that circulates liquid between the storage section 86 and the inside of the liquid discharge head 20. Therefore, the supply passage 87 includes a supply passage 37 that sends liquid from the storage section 86 to the liquid discharge head 20, and a return passage 39 (see Figure 6) that returns liquid from the liquid discharge head 20 to the storage section 86. The supply passage 87 has a supply passage 37 and a return passage 39 for each storage section 86 that stores different types of liquid. Therefore, if the number of liquid containers 82 and storage sections 86 is N (where N is a natural number), the supply passage 87 is composed of 2N passages. The variable section 87A of the supply passage 87 is composed of, for example, 2N tubes. The connection section 89 of the joint section 88 has 2N pipe sections 89A. If the liquid dispensing device 11 is configured to print with, for example, four colors of ink, the supply channel 87 is composed of four feed channels 37 and four return channels 39.

[0051] As shown in Figure 4, the liquid dispensing device 11 includes a holding part 90 capable of holding the joint part 88 removed from the liquid dispensing head 20. The holding part 90 is configured as a bottomed box with an opening at the top. As shown in Figure 4, the holding part 90 may also have a dish shape with an opening 90A at the top. Here, a bottomed box with an opening at the top means a shape having a bottom with a mounting surface 90B on which the joint part 88 can be placed, and an annular outer circumference that is higher than the mounting surface 90B and surrounds the mounting surface 90B. The shape of the holding part 90 in plan view as seen from the vertical direction Z is not limited to a rectangle, but may also be a polygon other than a circle, ellipse, or quadrilateral. Furthermore, a dish shape means a shape in which the height dimension is shorter than the shortest dimension in the direction parallel to the mounting surface 90B of the holding part 90. The holding part 90 may be a dish shape having a bottom and sides, or it may be a dish shape in which the outer circumference of the bottom is bent or curved upward.

[0052] The holding portion 90 is positioned horizontally on the upper surface of the frame portion 12F with its opening 90A facing upward. The frame portion 12F may be part of the frame 12C that houses the liquid discharge head 20, etc., or it may be provided separately from the frame 12C. The frame portion 12F may also be part (for example, the upper part) of the housing frame that houses the liquid container 82. As shown in Figure 4, if the mounting portion 83 has a housing frame that houses the liquid container 82 as part of it, the holding portion 90 may be positioned on the upper surface of the mounting portion 83.

[0053] As shown in Figures 4 and 5, a locking portion 91 is provided on the inner circumference of the holding portion 90. The locking portion 91 may be provided closer to the outer circumference than the center of the mounting surface 90B of the holding portion 90. In the example shown in Figures 4 and 5, the locking portion 91 is provided on the bottom, but it may also be provided on the outer circumference (for example, the side). The locking portion 91 may have an L-shape, for example, as shown in the front view in Figures 4 and 5. The locking portion 91 is provided to lock with the joint portion 88 which is placed on the holding portion 90, and to hold the joint portion 88 in a position where the connecting portion 89 faces upward. In this regard, the shape and mechanism of the locking portion 91 can be selected as appropriate, as long as it is possible to hold the joint portion 88 in a position where the connecting portion 89 faces upward.

[0054] As shown in Figure 4, the liquid dispensing device 11 may include a cap 92 that is detachably provided on the holding part 90. The cap 92 is configured to be detachably attached to the connection part 89 of the joint part 88 that has been removed from the liquid dispensing head 20. The cap 92 can cover the connection part 89 of the removed joint part 88. The cap 92 may be held on the holding part 90 while locked to the locking part 91. In this case, the cap 92 may have a locked portion 92A that can engage with the locking part 91. The cap 92 may be held on the mounting surface 90B of the holding part 90 with the opening side of the lid facing downwards by the engagement of the locking part 91 and the locked portion 92A.

[0055] As shown in Figure 4, when the head is replaced, the liquid discharge head 20 is positioned at the replacement position PH2. The joint 88 is connected to the connected portion 22 located above the liquid discharge head 20 with the connecting portion 89 facing downwards. With the connecting portion 89 of the joint 88 and the connected portion 22 connected, at least a portion of the supply flow path 87 passes over the mounting portion 83 and is connected to the liquid discharge head 20.

[0056] When the operator removes the joint 88 from the connected part 22, they pull the joint 88 upward. This makes it possible to remove the joint 88 from the connected part 22 of the liquid discharge head 20. Here, the removal direction of the joint 88 is not limited to the -Z direction (upward), but may also be diagonally upward at an acute angle with respect to the -Z direction. Alternatively, the connected part 22 may be provided on the side in the depth direction X of the liquid discharge head 20 instead of on the top, and the joint 88 may be configured to be detachable from the connected part 22 in the depth direction X or diagonally at an acute angle with respect to the depth direction X.

[0057] As shown in Figure 5, the holding portion 90 is configured to hold the joint portion 88 with the connecting portion 89 facing upwards. The joint portion 88, removed from the liquid discharge head 20, is placed on the mounting surface 90B of the holding portion 90 by the operator. The holding portion 90 is positioned closer to the base end, which is one end of the supply channel 87 on the storage portion 86 side, than to the connected portion 22 of the liquid discharge head 20. The position of the holding portion 90 is set so that it is placed closer to the base end of the supply channel 87 extending from the storage portion 86 than to the position where the joint portion 88 is connected to the connected portion 22 of the liquid discharge head 20 as shown in Figure 4.

[0058] In particular, when the supply channel 87 has a variable section 87A and a fixed section 87B, as shown in Figure 5, the base end 87E, which is one end of the variable section 87A on the fixed section 87B side of the supply channel 87, is assumed to be in the position shown in the figure. In this case, the holding section 90 is provided in a position closer to the base end 87E, which is one end of the variable section 87A on the fixed section 87B side of the supply channel 87, than to the connected section 22 of the liquid discharge head 20.

[0059] Therefore, as shown in Figure 5, the joint portion 88 is more easily held in the holding portion 90 with the connecting portion 89 facing upwards. In other words, even if the joint portion 88 is placed in the holding portion 90 with the connecting portion 89 facing upwards, which is the opposite direction to when the connecting portion 89 faces downwards when it is connected to the connected portion 22 of the liquid discharge head 20, no undue force is applied to the supply channel 87. As shown in Figure 5, the supply channel 87 extending from the joint portion 88 is held in a path that forms an arc. In other words, when the joint portion 88 is placed in the holding portion 90 with the connecting portion 89 facing upwards, the supply channel 87 is held in a path that forms an arc, making it less susceptible to loads such as tension, bending, or twisting.

[0060] The joint portion 88 has a locked portion 88A at a position corresponding to the locking portion 91. The joint portion 88 is held in the holding portion 90 with the connecting portion 89 facing upward when the locking portion 91 and the locked portion 88A are engaged. The joint portion 88 tends to lose its upward-facing position due to the elastic reaction force received from the curved supply channel 87. However, since the joint portion 88 is locked to the holding portion 90 by the engagement of the locking portion 91 and the locked portion 88A, even if it receives an elastic reaction force from the supply channel 87 or if an operator performing head replacement work accidentally touches it, the connecting portion 89 will be held in an upward-facing position. As a result, liquid is less likely to drip from the connecting portion 89 of the joint portion 88, and even if liquid does drip, the dripped liquid will accumulate in the holding portion 90. Therefore, contamination of the inside of the device body 12 by liquid dripping from the joint portion 88 is suppressed.

[0061] Next, before describing the configuration of the liquid dispensing device 11 that adopts viewpoint 2, the configuration of the liquid supply unit 80 used to realize a configuration that can prevent or reduce liquid dripping will be described with reference to Figure 6. Figure 6 shows a part of the liquid supply unit 80 that supplies liquid from the storage section 86 that stores one type of liquid to the liquid dispensing head 20.

[0062] As shown in Figure 6, the liquid supply unit 80 includes the aforementioned liquid supply section 81. The liquid supply section 81 includes a mounting section 83 to which a liquid container 82 is detachably attached, and a supply mechanism 85 including a storage section 86 connected to the liquid container 82 via the mounting section 83. The supply mechanism 85 supplies the liquid stored in the storage section 86 to the liquid discharge head 20. The storage section 86 includes a first storage section 33 and a second storage section 35.

[0063] The liquid dispensing device 11 may include a plurality of supply mechanisms 85. Each of the supply mechanisms 85 may supply a different type of liquid to the liquid dispensing head 20. For example, the liquid dispensing device 11 may perform color printing by dispensing multiple colors of ink supplied by the plurality of supply mechanisms 85.

[0064] As shown in Figure 6, the liquid supply unit 80 includes a drive mechanism 57 that drives the supply mechanism 85. If multiple supply mechanisms 85 are provided depending on the type of liquid, the liquid dispensing device 11 may include multiple drive mechanisms 57 that drive the multiple supply mechanisms 85 individually. Alternatively, the liquid dispensing device 11 may include a single drive mechanism 57 that drives the multiple supply mechanisms 85 together.

[0065] The liquid container 82 may include a storage chamber 29 for storing liquid, a discharge section 30 for discharging the liquid stored in the storage chamber 29, and a discharge valve 31 provided in the discharge section 30. In this embodiment, the storage chamber 29 is a sealed space that does not communicate with the atmosphere. Before being mounted on the mounting section 83, the liquid container 82 may contain a larger amount of liquid than the amount of liquid that the supply mechanism 85 can hold.

[0066] The supply mechanism 85 includes a first storage section 33 and a second storage section 35 as a storage section 86 for storing the liquid supplied from the liquid container 82. The first storage section 33 and the second storage section 35 are connected through a connecting passage 34. The supply mechanism 85 includes a one-way valve 36 that can open and close the connecting passage 34.

[0067] The supply channel 87 includes a feed channel 37 connecting the second storage section 35 and the liquid discharge head 20, and a return channel 39 connecting the liquid discharge head 20 and the first storage section 33. The feed channel 37 is a channel that supplies liquid from the second storage section 35 to the liquid discharge head 20. The return channel 39 is a channel through which liquid returns from the liquid discharge head 20 to the first storage section 33.

[0068] The return channel 39 may be partially equipped with a liquid chamber 41. Part of the liquid chamber 41 is composed of a flexible portion 42, and the volume changes as the flexible portion 42 deforms. The supply mechanism 85 includes a first valve 38 that can open and close the supply passage 37 and a second valve 40 that can open and close the return passage 39. The valves 38 and 40 are located in the middle of the supply passage 87. Specifically, the first valve 38 is located in the middle of the supply passage 37. The second valve 40 is located in the middle of the return passage 39. The second valve 40 is located in the return passage 39 between the liquid chamber 41 and the first storage section 33.

[0069] Valves 38 and 40 are, for example, solenoid valves and are controlled by the control unit 100. Thus, the liquid discharge device 11 comprises valves 38 and 40 that can open and close the supply passage 87, and a control unit 100 that can control the opening and closing of valves 38 and 40.

[0070] Valves 38 and 40 are normally closed valves that automatically close the supply channel 87 when the power is turned off. Specifically, the first valve 38 is a normally closed valve that automatically closes the supply channel 37 when the power is turned off. The second valve 40 is a normally closed valve that automatically closes the return channel 39 when the power is turned off.

[0071] In this embodiment, valves 38 and 40 are configured to be manually opened and closed when the power is off. When performing head replacement work with the power off, the operator can manually switch the first valve 38 and the second valve 40, which are in the closed state, to the open state.

[0072] The liquid discharge head 20 has a first flow path 44 through which a supply flow path 37 is connected via a connection between a joint 88 and a connected part 22, and a second flow path 45 through which a return flow path 39 is connected via a connection between a joint 88 and a connected part 22. Both the first flow path 44 and the second flow path 45 are connected to the head flow path 201. That is, the downstream end of the first flow path 44, the upstream end of the second flow path 45, and the upstream end of the head flow path are in communication with each other via a liquid chamber (not shown). The head flow path 201 is connected to a common flow path 202. The common flow path 202 is in communication with a nozzle 21N via a pressure chamber (not shown). A piezoelectric element is provided on a part of the wall of the pressure chamber, and when the volume of the pressure chamber changes due to the driving of the piezoelectric element, liquid is discharged from the nozzle 21N which is in communication with the pressure chamber.

[0073] A filter 46 is provided in the middle of the head flow path 201. Liquid from which foreign matter and air bubbles have been removed by the filter 46 is supplied to the common flow path 202 and nozzle 21N. This suppresses discharge failures in the nozzle 21N caused by foreign matter and air bubbles. The filter 46 has a mesh structure or a porous structure.

[0074] When the liquid discharge head 20 is at the printing position PH1, which is the lowest position in the vertical Z direction on the movement path that can be moved in direction B by the movement mechanism 110, the liquid level in the storage section 86 is lower than the opening height position of any nozzle 21N. The first storage section 33 and the second storage section 35 are connected via a communication passage 34 equipped with a one-way valve 36 that can be opened and closed by differential pressure. Therefore, the first liquid level 66, which is the liquid level of the first storage section 33, and the second liquid level 70, which is the liquid level of the second storage section 35, are often at approximately the same height. Even if one of the first or second liquid levels fluctuates to a maximum higher than the standard height position, the opening height position of the nozzle 21N is set to be higher than the liquid level at that time.

[0075] Therefore, a negative pressure is generated in the liquid inside the nozzle 21N due to the difference in water head between the first liquid level 66 of the first storage section 33, the second liquid level 70 of the second storage section 35, and the liquid level of the meniscus formed at the opening of the nozzle 21N. This negative pressure prevents the liquid from dripping from the nozzle 21N. In addition, this negative pressure causes a meniscus to form in the liquid inside the nozzle 21N.

[0076] The drive mechanism 57 includes a pump 47 for adjusting the pressure in the gas phase within the second storage section 35. The drive mechanism 57 may also include a switching mechanism 48 connected to the pump 47 and a pressure sensor 49 for detecting pressure. The drive mechanism 57 may also include an atmospheric vent passage 50 connected to the first storage section 33, a pressurized passage 51 connected to the second storage section 35, and a connecting passage 52 connecting the atmospheric vent passage 50 and the pressurized passage 51 to the pump 47.

[0077] Pump 47 is a tube pump that pumps air by, for example, rotating a roller while compressing a tube. A tube (not shown) of pump 47 has an air passage 55 connected to one end and a connecting passage 52 connected to the other end. When pump 47 is driven in the forward direction, it sends air taken in from the air passage 55 to the connecting passage 52. When pump 47 is driven in the reverse direction, it sends air taken in from the connecting passage 52 to the air passage 55.

[0078] The air passage 55 is connected to the variable volume mechanism 58. The variable volume mechanism 58 is a mechanism that changes the volume of the liquid chamber 41. The variable volume mechanism 58 comprises a flexible portion 42, an air chamber 53 separated from the liquid chamber 41 via the flexible portion 42, and a spring 54 provided in the air chamber 53. The air passage 55 is in communication with the air chamber 53. The spring 54 pushes the flexible portion 42, thereby reducing pressure fluctuations in the return passage 39 and the liquid in the liquid discharge head 20 by changing the volume of the liquid chamber 41. The variable volume mechanism 58 changes the volume of the liquid chamber 41 separated from the air chamber 53 via the flexible portion 42 by pressurizing or depressurizing the air chamber 53 through the air passage 55. In other words, the variable volume mechanism 58 changes the volume of the liquid chamber 41 by air pressure drive. The variable volume mechanism 58 is provided in the return passage 39 between the liquid discharge head 20 and the second valve 40, and is driven, for example, to pressurize the liquid in the return passage 39.

[0079] <Configuration of the first storage section 33> Next, the first storage section 33 will be described. The first storage section 33 has an introduction section 60 into which the liquid contained in the liquid container 82 attached to the mounting section 83 can be introduced. The first storage section 33 may also have an introduction valve 61 provided in the introduction section 60, a first storage chamber 62 for storing liquid, a liquid level sensor 63 for detecting the amount of liquid stored in the first storage chamber 62, and a first gas-liquid separation membrane 64 separating the first storage chamber 62 from the atmospheric outlet passage 50. The first gas-liquid separation membrane 64 is a membrane that allows gas to pass through but does not allow liquid to pass through.

[0080] The outlet valve 31 and the inlet valve 61 open when the liquid container 82 is attached to the mounting portion 83, and remain open while the liquid container 82 is attached to the mounting portion 83. By configuring the inlet valve 61 to open before the outlet valve 31 when the liquid container 82 is attached to the mounting portion 83, the risk of liquid leakage from the liquid container 82 can be reduced.

[0081] The introduction section 60 is provided on the upper part of the first storage section 33. In this embodiment, the introduction section 60 is provided by penetrating the top plate 65 of the first storage chamber 62. The lower end of the introduction section 60 is located at a predetermined height of the first storage chamber 62. The introduction section 60 is connected to the outlet section 30 of the liquid container 82 when the liquid container 82 is attached to the mounting section 83 of the introduction section 60.

[0082] The lower end of the inlet 60 is located below the nozzle surface 21A. As a result, the first liquid level 66 of the liquid stored in the first storage section 33 fluctuates within a range lower than the nozzle surface 21A. Specifically, the liquid in the liquid container 82 is supplied to the first storage section 33 via the outlet 30 and the inlet 60 by the water head. Air is introduced into the liquid container 82 from the first storage section 33 via the inlet 60 and the outlet 30 by the same amount as the liquid supplied to the first storage section 33. The first liquid level 66 rises by the amount of the supplied liquid. When the first liquid level 66 reaches the lower end of the inlet 60, the inflow of air from the first storage section 33 to the liquid container 82 is restricted. Since the storage chamber 29 is sealed, when the inflow of air is restricted, the pressure inside the storage chamber 29 decreases by the amount of the supplied liquid. When the negative pressure inside the containment chamber 29 becomes greater than the water head of the liquid inside the containment chamber 29, the supply of liquid from the liquid containment body 82 to the first storage section 33 is restricted.

[0083] The first liquid level 66 decreases as liquid is supplied from the first storage section 33 to the second storage section 35. As the first liquid level 66 decreases and air flows into the storage chamber 29 through the inlet 60 and outlet 30, the negative pressure inside the storage chamber 29 decreases. When the negative pressure inside the storage chamber 29 becomes less than the water head of the liquid inside the storage chamber 29, liquid is supplied from the liquid container 82 to the first storage section 33. Therefore, as long as there is liquid in the liquid container 82, the first liquid level 66 is maintained at a standard position near the lower end of the inlet 60. When there is no more liquid in the liquid container 82, the first liquid level 66 is located below the standard position.

[0084] The liquid level sensor 63 may detect when the first liquid level 66 is at the standard position, when the first liquid level 66 is below the standard position, or when the first liquid level 66 is at the full position above the standard position. When the first liquid level 66 is at the full position, the first storage unit 33 is storing the maximum amount of liquid. When the liquid level sensor 63 detects that the first liquid level 66 is below the standard position, the control unit 100 may determine that the liquid container 82 is empty and instruct the user to replace the liquid container 82.

[0085] In this embodiment, the standard position is located above the position where the downstream end of the return channel 39 is connected in the first storage chamber 62. Therefore, when the first liquid level 66 is at the standard position, the liquid in the first storage section 33 can be supplied to the liquid discharge head 20 via the return channel 39.

[0086] <Configuration of the second storage section 35> Next, the second storage section 35 will be described. The second storage section 35 may include a second storage chamber 68 for storing liquid and a second gas-liquid separation membrane 69 that separates the second storage chamber 68 from the pressurized flow path 51. The second gas-liquid separation membrane 69, like the first gas-liquid separation membrane 64, is a membrane that allows gas to pass through but prevents liquid from passing through.

[0087] The second storage section 35 is supplied with liquid from the first storage section 33 due to the difference in water head. A one-way valve 36 allows the flow of liquid from the first storage section 33 to the second storage section 35 and restricts the flow of liquid from the second storage section 35 to the first storage section 33. The one-way valve 36 is, for example, a differential pressure valve. The one-way valve 36, being a differential pressure valve, opens and closes due to the differential pressure based on the difference in water head between the liquid in the first storage section 33 and the liquid in the second storage section 35. The one-way valve 36 may also have a check valve configuration. When the pressure inside the first storage chamber 62 and the second storage chamber 68 is atmospheric pressure, the second liquid level 70 in the second storage section 35 is at the same height as the first liquid level 66. In other words, the second liquid level 70 is maintained at a standard position that is approximately the same height as the lower end of the inlet section 60 and fluctuates within a range lower than the nozzle surface 21A. The liquid in the liquid discharge head 20 is maintained at a negative pressure due to the difference in hydrostatic head between it and the liquids in the first storage section 33 and the second storage section 35. When the liquid is consumed in the liquid discharge head 20, the liquid stored in the second storage section 35 is supplied to the liquid discharge head 20.

[0088] The one-way valve 36 closes the communication passage 34 when the pressure in the second storage section 35 is greater than the pressure in the first storage section 33. Therefore, the one-way valve 36 closes the communication passage 34 when the second storage section 35 is pressurized by the pump 47.

[0089] The first valve 38 and the second valve 40 are controlled to open and close by the control unit 100. The first valve 38 is provided to open and close the supply passage 37 when pressurized by the pump 47. The second valve 40 is provided to open and close the return passage 39.

[0090] <Configuration of switching mechanism 48> Next, the switching mechanism 48 will be described. The switching mechanism 48 comprises a narrow tube section 72 provided in the connecting flow path 52, and first selector valves 73a to eleventh selector valves 73k that can open and close the flow path. The narrow tube section 72 is a narrow and meandering tube such that the flow of liquid is greatly restricted compared to the flow of air.

[0091] The first selector valve 73a, when opened, connects the air passage 55 to the atmosphere. The second selector valve 73b, when opened, connects the air passage 55 to the pressure sensor 49. The third selector valve 73c, when opened, opens the air passage 55 and connects the pump 75 to the air chamber 53.

[0092] The fourth selector valve 73d opens to connect the connecting passage 52 between the pump 47 and the eighth selector valve 73h to the atmosphere. The fifth selector valve 73e opens to connect the connecting passage 52 to the pressure sensor 49. The sixth selector valve 73f and the seventh selector valve 73g open to connect the connecting passage 52 to the atmosphere. The eighth selector valve 73h opens to open the connecting passage 52. The ninth selector valve 73i opens to connect the narrow tube section 72 to the atmosphere. The tenth selector valve 73j opens to open the atmospheric opening passage 50, connecting the first storage section 33 to the connecting passage 52. The eleventh selector valve 73k opens to open the pressurized passage 51, connecting the second storage section 35 to the connecting passage 52.

[0093] When changing the pressure in the air chamber 53, the switching mechanism 48 opens the second selector valve 73b and the third selector valve 73c, and closes the other selector valves. When the pump 75 is driven forward in this state, the air in the air chamber 53 is discharged through the air passage 55, and the pressure in the air chamber 53 decreases. When the pump 75 is driven in reverse in this state, air is supplied to the air chamber 53 through the air passage 55, and the pressure in the air chamber 53 increases. At this time, the pressure sensor 49 may detect the pressure in the air passage 55 and the air chamber 53. The control unit 100 may control the driving of the pump 47 based on the detection result of the pressure sensor 49.

[0094] In this embodiment, the drive unit 59 is comprised of a pump 75, an air passage 55, an air chamber 53, and a spring 54. In this respect, the liquid discharge device 11 includes the drive unit 59. The supply passage 87 has a flexible portion 42 that is flexible in at least part of it. The drive unit 59 may be configured to displace the flexible portion 42 in a direction that increases the volume of the supply passage 87, and to maintain the displaced state of the flexible portion 42. Specifically, the drive unit 59 displaces the flexible portion 42 in a direction that increases the volume of the supply passage 87 when the pump 75 is driven in reverse with the third selector valve 73c open. When the third selector valve 73c is closed in this state, the displaced state of the flexible portion 42 can be maintained.

[0095] The drive unit 59 may be configured to be controllable by the control unit 100 and also to be manually operable. In this case, the pump 75 may include an operating unit 75A that is controlled by the control unit 100 and is also manually operable.

[0096] The switching mechanism 48 may be configured to be controllable by the control unit 100 and also to be manually operable. In this case, the switching mechanism 48 may include a cam mechanism (not shown) configured to select the opening and closing of the selector valves 73a to 73k. The control unit 100 is configured to select the opening and closing of the selector valves 73a to 73k by driving the cam mechanism. The switching mechanism 48 may also include an operating unit 74 that allows the cam mechanism to be manually operated. In this regard, the third selector valve 73c, which constitutes the drive unit 59 of the switching mechanism 48, is configured to be controllable by the control unit 100 and also to be manually operable by the operating unit 74.

[0097] The variable capacity mechanism 58 may also be used to slightly pressurize the liquid in the liquid discharge head 20 by changing the flexible portion 42. Slight pressurization refers to pressurization sufficient to break the meniscus of the nozzle 21N. With the first valve 38 and the second valve 40 open, the control unit 100 draws liquid into the liquid chamber 41 by depressurizing the air chamber 53 for a predetermined depressurization time, and then closes the first valve 38 and the second valve 40. In this state, the control unit 100 slightly pressurizes the liquid in the liquid discharge head 20 by pressurizing the air chamber 53 for a slight pressurization time to push out the liquid in the liquid chamber 41. The slight pressurization time is longer than the time required for the pressure from pushing out the liquid in the liquid chamber 41 to be transmitted to the liquid in the nozzle 21N. After the slight pressurization is complete, the control unit 100 releases the air chamber 53 to the atmosphere.

[0098] When the first storage section 33 is opened to the atmosphere, the switching mechanism 48 opens the sixth selector valve 73f and the tenth selector valve 73j. The first storage chamber 62 is in communication with the atmosphere via the atmospheric opening passage 50 and the connecting passage 52.

[0099] When the second storage section 35 is opened to the atmosphere, the switching mechanism 48 opens the seventh selector valve 73g and the eleventh selector valve 73k. The second storage chamber 68 is in communication with the atmosphere via the pressurized passage 51 and the connecting passage 52.

[0100] When pressurizing the second storage section 35, the switching mechanism 48 opens the first selector valve 73a, the fifth selector valve 73e, the eighth selector valve 73h, and the eleventh selector valve 73k, and closes the other selector valves. When the pump 47 is driven forward in this state, air flows into the second storage chamber 68 via the air passage 55, the connecting passage 52, and the pressurizing passage 51, and the pressure in the second storage chamber 68 increases. At this time, the pressure sensor 49 may detect the pressure in the connecting passage 52, the pressurizing passage 51, and the second storage chamber 68. The control unit 100 may control the driving of the pump 47 based on the detection result of the pressure sensor 49. With the first valve 38 open and the second valve 40 closed, the control unit 100 pressurizes the second storage section 35 to perform cleaning, which involves discharging liquid from the nozzle 21N of the liquid discharge head 20.

[0101] When the pressure inside the first storage section 33 is reduced, the switching mechanism 48 opens the first selector valve 73a, the fifth selector valve 73e, the eighth selector valve 73h, and the tenth selector valve 73j, and closes the other selector valves. When the pump 47 is driven in reverse in this state, air in the first storage chamber 62 is discharged through the air passage 55, the connecting passage 52, and the atmospheric release passage 50, and the pressure inside the first storage chamber 62 decreases. At this time, the pressure sensor 49 may detect the pressure in the connecting passage 52, the atmospheric release passage 50, and the first storage chamber 62. The control unit 100 may control the driving of the pump 47 based on the detection result of the pressure sensor 49.

[0102] When reducing the pressure inside the second storage section 35, the switching mechanism 48 opens the first selector valve 73a, the fifth selector valve 73e, the eighth selector valve 73h, and the eleventh selector valve 73k, and closes the other selector valves. When the pump 47 is driven in reverse in this state, air in the second storage chamber 68 is discharged through the air passage 55, the connecting passage 52, and the pressurizing passage 51, and the pressure inside the second storage chamber 68 decreases. At this time, the pressure sensor 49 may detect the pressure in the connecting passage 52, the pressurizing passage 51, and the second storage chamber 68. The control unit 100 may control the driving of the pump 47 based on the detection result of the pressure sensor 49.

[0103] In this embodiment, the pressure reducing section 76 is composed of a pump 47, a connecting passage 52, an atmospheric outlet passage 50, a pressurizing passage 51, a first selector valve 73a, a fifth selector valve 73e, an eighth selector valve 73h, a tenth selector valve 73j, and an eleventh selector valve 73k. In this respect, the liquid discharge device 11 is equipped with a pressure reducing section 76 that can reduce the pressure in the spaces within the storage sections 33 and 35.

[0104] In this embodiment, the 10th selector valve 73j and the 11th selector valve 73k constitute the pressure reduction maintenance unit 77. In this respect, the liquid discharge device 11 includes a pressure reduction maintenance unit 77 capable of maintaining the pressure reduction by the pressure reduction unit 76. The pressure reduction unit 76 and the pressure reduction maintenance unit 77 may be configured to be controllable by the control unit 100 and to be manually operable. In this case, the pump 47 may include an operating unit 47A that is configured to be controllable by the control unit 100 and to be manually operable. Furthermore, the 1st selector valve 73a, the 5th selector valve 73e, the 8th selector valve 73h, the 10th selector valve 73j, and the 11th selector valve 73k, which constitute the pressure reduction unit 76, are configured to be controllable by the control unit 100 and to be manually operable by the aforementioned operating unit 74. Furthermore, the 10th selector valve 73j and the 11th selector valve 73k, which constitute the pressure reduction maintenance unit 77, are configured to be controllable by the control unit 100 and to be manually operable by the aforementioned operating unit 74.

[0105] <Operation of the First Embodiment> Next, the operation of this embodiment will be described. The operator operates the control unit 19A to select the service mode on the menu screen displayed on the display unit 19, and then selects the "Head Replacement" item. When the control unit 100 receives the instruction to replace the head, it reverses the motor 113 to move the liquid discharge head 20 along the -B direction to the replacement position PH2. When the control unit 100 detects that the liquid discharge head 20 has moved to the replacement position PH2 based on a detection signal from a sensor (not shown), it stops the motor 113. Before, during, or immediately after the movement of the liquid discharge head 20, the control unit 100 executes the drip suppression control routine shown in Figure 9 via a computer. Note that during this head replacement operation, printing is not in progress, so the first valve 38 and the second valve 40 are in a closed state.

[0106] In step S11, the control unit 100 draws the liquid in the liquid discharge head 20 upstream. The control unit 100 causes the variable volume mechanism 58 to perform the draw-in operation. Specifically, the control unit 100 controls the switching mechanism 48 to open the second selector valve 73b and the third selector valve 73c, and close the other selector valves. In this state, the control unit 100 drives the pump 75 in the forward direction. In the initial state shown in Figure 7, the air in the air chamber 53 is discharged through the air passage 55, and the pressure in the air chamber 53 decreases. Then, as shown in Figure 8, the reduced pressure in the air chamber 53 causes the flexible part 42 to be pulled up towards the air chamber 53 against the biasing force of the spring 54, and the volume of the liquid chamber 41 increases accordingly. When the volume of the liquid chamber 41 increases, the liquid in the supply passage 87 downstream of the first valve 38 and upstream of the liquid chamber 41 is drawn into the liquid chamber 41. In other words, as shown by the white arrows in Figure 8, liquid is drawn into the liquid chamber 41 from the liquid discharge head 20 side, which is upstream of the liquid chamber 41. As a result, the liquid downstream of the filter 46 (towards the nozzle 21N) within the liquid discharge head 20 is drawn upstream by an amount corresponding to the volume of the liquid chamber 41. The gas-liquid interface that was formed by the meniscus inside the nozzle 21N moves towards the filter 46 side. In other words, air is drawn in from the nozzle 21N, and the air region moves to the back (upstream) of the nozzle 21N.

[0107] In the next step S12, the control unit 100 determines whether the number of liquid draw-in cycles has reached the set number N. If the set number N has not been reached, the process proceeds to step S13; if the set number N has been reached, the routine terminates.

[0108] In the next step S13, the control unit 100 opens valves 38 and 40. That is, the control unit 100 switches the first valve 38 and the second valve 40 from a closed state to an open state.

[0109] In the next step S14, the control unit 100 sends the drawn-in liquid to the storage unit 33. The control unit 100 sends the liquid drawn into the liquid chamber 41 to the storage unit 33. The control unit 100 either opens the air chamber 53 to the atmosphere or reverses the pump 75. In the former case, the flexible part 42 is pushed down by the biasing force of the spring 54, reducing the volume of the liquid chamber 41. In the latter case, the flexible part 42 is pushed down by the air introduced into the air chamber 53 and the biasing force of the spring 54. This reduces the volume of the liquid chamber 41. At this time, the liquid is pushed out of the liquid chamber 41, and the pushed-out liquid flows into the first storage chamber 62 due to the difference in liquid head between the liquid discharge head 20 and the first storage unit 33.

[0110] In step S15, the control unit 100 closes valves 38 and 40. That is, the control unit 100 switches the first valve 38 and the second valve 40 from an open state to a closed state.

[0111] After completing the process in step S15, the control unit 100 returns to step S11. Then, in step S12, the control unit 100 repeats the processes in steps S11, S13, S14, and S15 until the number of liquid draw-in operations reaches the set number N. In this way, each time the control unit 100 performs a draw-in operation to draw liquid into the liquid chamber 41, it determines whether the set number N has been reached. If the set number N has not been reached, it sends the liquid drawn into the liquid chamber 41 to the first storage chamber 62. When the number of liquid draw-in operations reaches the set number N, the routine is terminated.

[0112] When the control unit 100 terminates the liquid drip suppression control, the first valve 38 and the second valve 40 are closed, and the flexible portion 42 of the variable volume mechanism 58 is displaced in a direction that increases the volume of the liquid chamber 41. As a result, the negative pressure generated in the supply channel 87 when liquid was last drawn into the liquid chamber 41 is maintained.

[0113] In this way, the control unit 100 performs a set number of liquid draw-in operations N times and (N-1) liquid discharge operations through the processing in steps S11 to S15. The control unit 100 terminates the routine with liquid drawn into the liquid chamber 41.

[0114] The variable-capacity mechanism 58 performs a liquid drawing operation a set number of times N, for example, a predetermined number of times between 2 and 5. As a result, a portion of the liquid in the liquid discharge head 20 is drawn towards the supply channel 87.

[0115] Here, the set number of cycles N may be determined by the relationship between the amount of liquid drawn in Q per drive of the variable-volume mechanism 58 and the flow path volume Vh from the filter 46 in the liquid discharge head 20 to the opening of the nozzle 21N. That is, the set number of cycles N may be set to the number of times it takes for the liquid-gas interface (meniscus interface) of the liquid in the liquid discharge head 20 to reach the filter 46. For example, the set number of cycles N may be set to the minimum value Nmin among the natural numbers N that satisfy N≧Vh / Q, or to the minimum value Nmin plus "1" (Nmin+1) cycles.

[0116] The filter 46 has a mesh structure or porous structure containing numerous micropores. When the liquid's gas-liquid interface reaches the filter 46, a liquid meniscus (hereinafter also referred to as "micro-meniscus") is formed in the numerous micropores. The value of the bubble point Bp of this micro-meniscus is a predetermined value, for example, within the range of 5 to 10 kPa. This bubble point prevents the liquid's gas-liquid interface from moving upstream of the filter 46. As a result, air can be drawn into the flow path region from the nozzle 21N to the filter 46 within the liquid discharge head 20. Furthermore, a relatively high negative pressure (however, a negative pressure below the bubble point) can be generated in the liquid in the flow path portion upstream of the filter 46 due to the micro-meniscus.

[0117] When the control unit 100 has finished controlling the dripping, it displays information on the display unit 19 indicating that the head is ready for replacement. The operator removes the discharge tray 18A from the main body 12 of the device. The operator removes the joint 88 from the liquid discharge head 20 at the replacement position PH2 by loosening a screw (not shown), for example.

[0118] When an operator removes the joint 88 from the liquid discharge head 20, they may unintentionally press the tube of the supply channel 87 or apply excessive force to the joint 88. At this time, the gas-liquid interface inside the liquid discharge head 20 is located further back from the nozzle 21N than during printing. Therefore, even if the gas-liquid interface inside the liquid discharge head 20 is slightly displaced towards the nozzle 21N, liquid will not drip from the nozzle 21N.

[0119] At this time, the gas-liquid interface within the liquid discharge head 20 has reached the filter 46, so unless pressure exceeding the bubble point is applied to the liquid in the liquid discharge head 20, the movement of the liquid toward the nozzle 21N is prevented. Even if pressure exceeding the bubble point is applied to the liquid in the liquid discharge head 20 and the gas-liquid interface is slightly displaced from the filter 46 toward the nozzle 21N, the liquid will not drip from the nozzle 21N.

[0120] Furthermore, until the joint 88 is removed from the liquid discharge head 20, a relatively large negative pressure (negative pressure near the bubble point) acts on the liquid in the supply channel 87. Therefore, when the joint 88 is removed from the liquid discharge head 20, the liquid meniscus in the connection part 89 moves inward. As a result, even if the above-mentioned disturbances (a) to (c) occur after the joint 88 has been removed, such as when an operator accidentally pushes the tube of the supply channel 87 or applies acceleration or impact to the joint 88, the dripping of liquid from the connection part 89 of the joint 88 is suppressed.

[0121] The worker places the removed joint 88 on the inner bottom surface of the holding part 90 with the connecting part 89 facing upward. At this time, the locking part 91 and the locked part 88A are locked together. This locking ensures that the joint 88 is held in an upward-facing position even when subjected to an elastic reaction force from the tube of the supply channel 87. Because the connecting part 89 faces upward, dripping of liquid from the connecting part 89 is suppressed. Furthermore, even if a small amount of liquid drips from the connecting part 89 and runs down the side of the joint 88 before it is placed on the holding part 90, the liquid that runs down the side is caught by the dish-shaped holding part 90. Therefore, even if liquid drips from the connecting part 89, contamination of the inside of the device body 12 is suppressed.

[0122] As shown in Figure 5, the worker attaches the cap 92 to the joint 88 so as to cover the connection part 89. Even if the joint 88 comes off the retaining part 90 or the joint 88 tips over or tilts due to the worker's negligence or the elastic reaction force of the tube, liquid will not leak from the connection part 89 covered by the cap 92, thus preventing the liquid from the joint 88 from contaminating the retaining part 90 or its surroundings. In addition, the cap 92 attached to the joint 88 prevents the ink or other liquid inside the connection part 89 from becoming thicker or drying out.

[0123] Then, the operator removes the liquid discharge head 20 from the main body 12 of the device. The operator pulls the liquid discharge head 20, which is at the replacement position PH2, up in the -Z direction along the two guide rails 102 and 103. Then, the liquid discharge head 20 is removed from the opening 12D as shown by the dashed line in Figure 3.

[0124] Next, the new liquid discharge head 20 is attached to the main body 12 of the apparatus. The operator inserts the liquid discharge head 20 through the opening 12D by aligning the guide roller 20R of the liquid discharge head 20 with the guide rails 102 and 103. The liquid discharge head 20, inserted vertically in the Z direction along the guide rails 102 and 103, is positioned at the replacement position PH2 shown by the solid line in Figure 3. After that, the operator removes the cap 92 from the joint 88 held in the holding part 90 and connects the joint 88 to the connected part 22 of the liquid discharge head 20. For example, the operator fixes the joint 88 connected to the connected part 22 to the liquid discharge head 20 by tightening a screw. The operator holds the cap 92 in the holding part 90. At this time, the cap 92 is held in the holding part 90 with the locking part 91 and the locked part 92A locked together. Finally, the discharge tray 18A is attached to the main body 12 of the apparatus so as to close the opening 12D. In this way, the liquid dispensing head 20 is replaced.

[0125] <Suppression of liquid dripping when the power is off> Next, we will describe the head replacement procedure performed while the liquid dispensing device 11 is powered off. There may be cases where the head replacement procedure must be performed while the liquid dispensing device 11 is powered off due to a malfunction in the power circuit, a power outage, or some other reason.

[0126] The operator manually drives the pump 47 and the switching mechanism 48 in the same manner as the liquid drip suppression control. Since the first valve 38 and the second valve 40 are normally closed valves, the supply passage 87 is closed when the power is turned off.

[0127] The operator manually switches the cam by operating the control unit 74 to select a switching position in which the second selector valve 73b and the third selector valve 73c are open and the other selector valves are closed. Next, the operator operates the control unit 47A to manually drive the pump 47 in the forward direction. From the initial state shown in Figure 7, the air in the air chamber 53 is discharged through the air passage 55, causing the pressure in the air chamber 53 to decrease. This decrease in pressure causes the flexible portion 42 to be pulled towards the air chamber 53 against the biasing force of the spring 54, as shown in Figure 8. As a result, liquid is drawn into the liquid chamber 41.

[0128] Next, the operator operates the control unit 38A to switch the first valve 38 from the closed state to the open state. The operator also operates the control unit 40A to switch the second valve 40 from the closed state to the open state. Furthermore, the operator manually pumps the liquid in the liquid chamber 41 to the first storage chamber 62. Specifically, the operator operates the control unit 74 to switch the cam and selects a switching position in which the first selector valves 73a to the third selector valves 73c are open and the other selector valves are closed. This opens the air chamber 53 to the atmosphere. As a result, the flexible part 42 is pushed down by the biasing force of the spring 54, and the volume of the liquid chamber 41 decreases. At this time, the liquid pushed out of the liquid chamber 41 flows into the first storage chamber 62. In this way, one pumping drive is performed to send a predetermined volume of liquid drawn in from the liquid discharge head 20 side through the supply passage 87 to the first storage chamber 62.

[0129] This liquid dispensing operation can also be performed by other means. After manually opening the first valve 38 and the second valve 40, the operator performs the following operation. The operator operates the control unit 74 to switch the cam and selects a switching position in which the second selector valve 73b and the third selector valve 73c are open and the other selector valves are closed. Next, the operator operates the control unit 75A to drive the pump 75 in reverse. Air is then introduced into the air chamber 53. The flexible part 42 is pushed down by the introduced air and the biasing force of the spring 54. As the volume of the liquid chamber 41 decreases, the liquid pushed out of the liquid chamber 41 flows into the first storage chamber 62. In this way, one pumping drive is performed to send a predetermined volume of liquid drawn in from the liquid discharge head 20 side through the supply passage 87 into the first storage chamber 62.

[0130] The operator manually performs a pumping action for a set number of times, for example, N. When manually pumping the variable capacity mechanism 58 while the power is off, the number of pumping actions may be less than the set number N during automatic control, or the operator may arbitrarily select a number of pumping actions below the upper limit.

[0131] <Effects of the First Embodiment> The effects of the first embodiment will be described. (1) The liquid dispensing device 11 includes a liquid dispensing head 20 capable of dispensing liquid. The liquid dispensing device 11 includes a storage section 86 configured to store the liquid supplied to the liquid dispensing head 20. The storage section 86 is located lower than the liquid dispensing head 20. The liquid dispensing device 11 includes a supply channel 87 that can connect the liquid dispensing head 20 and the storage section 86. The supply channel 87 is provided with a joint section 88 that can be attached to and detached from the liquid dispensing head 20. The liquid dispensing device 11 includes a holding section 90 capable of holding the joint section 88 when it has been removed from the liquid dispensing head 20. The joint section 88 has a connecting section 89 that is connected to the liquid dispensing head 20. The holding section 90 is configured to hold the joint section 88 with the connecting section 89 facing upwards. With this configuration, even if the joint section 88 of the supply channel 87 is removed from the liquid dispensing head 20, dripping of liquid from the connecting section 89 of the joint section 88 can be suppressed.

[0132] (2) The liquid dispensing device 11 is further equipped with a cap 92 that is detachably attached to the connection portion 89 of the joint portion 88 which has been removed from the liquid dispensing head 20, and is detachably attached to the holding portion 90. With this configuration, dripping of liquid from the connection portion 89 can be further suppressed.

[0133] (3) The holding part 90 is configured as a bottomed box with an opening at the top. With this configuration, even if liquid drips from the connecting part 89, it is possible to prevent it from adhering to other parts. (4) Valves 38 and 40 are normally closed valves that automatically close the supply channel 87 when the power is turned off. With this configuration, it is possible to prevent liquid from continuing to overflow from the nozzle in the event of an unforeseen situation when the power is turned off.

[0134] (5) The liquid discharge device 11 includes a drive unit 59. The supply channel 87 has a flexible portion 42 that is flexible in at least part of it. The drive unit 59 displaces the flexible portion 42 in a direction that increases the volume of the supply channel 87 and is capable of maintaining the displaced state of the flexible portion 42. The drive unit 59 is configured to be controllable by the control unit 100 and is also configured to be manually operable. With this configuration, when the supply channel 87 is removed from the liquid discharge head 20, negative pressure can be applied to the connection portion 89 of the joint portion 88.

[0135] (6) The drive unit 59 displaces the flexible part 42 in a direction that increases the volume of the supply channel 87, and before maintaining the displaced state of the flexible part 42, it displaces the flexible part 42 in a direction that increases the volume of the supply channel 87 and displaces the flexible part 42 in a direction that decreases the volume of the supply channel 87, thereby sending liquid into the storage unit 86. With this configuration, when the joint part 88 is removed from the liquid discharge head 20, dripping of liquid from the nozzle 21N of the liquid discharge head 20 can be suppressed.

[0136] (7) The liquid discharge head 20 further includes a mounting section 83 on which a liquid container 82 for containing the liquid to be supplied to the storage section 86 is detachably provided. The liquid discharge head 20 has a connected portion 22 that can be connected to a connecting portion 89 of a joint portion 88. The holding portion 90 is provided at a position closer to the base end, which is one end of the supply channel 87 on the storage section 86 side, than to the connected portion 22 of the liquid discharge head 20. With this configuration, it is easy to hold the joint portion 88 that has been removed from the liquid discharge head 20 in the holding portion 90. For example, when an operator places the removed joint portion 88 on the holding portion 90, it is less likely that stress will be applied to the supply channel 87 due to pulling, bending, or twisting.

[0137] (Second Embodiment) Next, a second embodiment will be described. The second embodiment differs from the first embodiment in the content of the liquid drip suppression control. The configuration of the liquid discharge device 11 and its liquid supply unit is the same as in the first embodiment.

[0138] When the control unit 100 receives a command to replace the head, it moves the liquid discharge head 20 to the replacement position. The control unit 100 then executes the liquid drip suppression control routine shown in Figure 10 using a computer.

[0139] In step S21, the control unit 100 opens valves 38 and 40. That is, the control unit 100 switches the first valve 38 and the second valve 40 from a closed state to an open state. A negative pressure corresponding to the head difference between the liquids in the first storage chamber 62 and the second storage chamber 68 and the liquid at the nozzle surface 21A of the liquid discharge head 20 acts on the meniscus of the nozzle 21N. At this time, as the liquid discharge head 20 moves from the cap position to the replacement position, the height position of the nozzle surface 21A of the liquid discharge head 20 is displaced by a predetermined distance in the -Z direction. In other words, as the liquid discharge head 20 moves to the replacement position, the head difference between the liquid at the standard position in the first storage chamber 62 and the second storage chamber 68 and the liquid meniscus at the nozzle surface 21A of the liquid discharge head 20 becomes even larger, and the negative pressure acting on the meniscus in the nozzle 21N increases in accordance with that head difference. The liquid meniscus inside the liquid discharge head 20 moves towards the back (upstream) of the nozzle 21N.

[0140] In step S22, the control unit 100 depressurizes the storage sections 33 and 35. That is, the control unit 100 depressurizes the first storage chamber 62 and the second storage chamber 68. Specifically, the control unit 100 controls the switching mechanism 48 to open the first selector valve 73a, the fifth selector valve 73e, the eighth selector valve 73h, the tenth selector valve 73j, and the eleventh selector valve 73k, and close the other selector valves. In this state, the control unit 100 drives the pump 47 in reverse. As a result, air in the first storage chamber 62 is discharged via the air passage 55, the connecting passage 52, and the atmospheric release passage 50, and the pressure in the first storage chamber 62 decreases. At the same time, air in the second storage chamber 68 is discharged via the air passage 55, the connecting passage 52, and the pressurizing passage 51, and the pressure in the second storage chamber 68 decreases.

[0141] As the first storage chamber 62 and the second storage chamber 68 are depressurized, the negative pressure acting on the liquid at the liquid meniscus within the liquid discharge head 20, which is connected to these storage chambers 62 and 68 through the supply channel 87, increases further by the amount of the depressurization. As a result, the liquid meniscus within the liquid discharge head 20 moves further upstream. This movement of the meniscus creates an air region in the portion of the liquid discharge head 20 that includes the nozzle 21N.

[0142] Furthermore, depending on the head difference, which is based on the difference in the vertical distance Z between the liquid level in the storage chambers 62 and 68 and the meniscus height of the liquid in the liquid discharge head 20, and the pressure reduction value in the storage chambers 62 and 68, the meniscus of the liquid in the liquid discharge head 20 may reach the filter 46. In this case, as in the first embodiment, the entire region downstream of the filter 46, including the nozzle 21N, becomes an air region. A fine meniscus is formed in the filter 46.

[0143] In step S23, the control unit 100 maintains the reduced pressure in the storage chamber. Specifically, the control unit 100 closes the first selector valve 73a, the fifth selector valve 73e, the eighth selector valve 73h, the tenth selector valve 73j, and the eleventh selector valve 73k. At this point, if the storage chambers 62 and 68 are in communication with the stopped pump 47, air will gradually leak into the storage chambers 62 and 68 via the pump 47, causing the reduced pressure in the storage chambers 62 and 68 to gradually approach atmospheric pressure. For this reason, the control unit 100 maintains the reduced pressure in the first storage chamber 62 and the second storage chamber 68 by closing the tenth selector valve 73j and the eleventh selector valve 73k.

[0144] Thus, when the control unit 100 terminates the liquid drip suppression control, it displays information on the display unit 19 indicating that the head can be replaced. The operator removes the discharge tray 18A from the main body 12 of the device, and then removes the joint 88 from the liquid discharge head 20.

[0145] When an operator removes the joint 88 from the liquid discharge head 20, they may unintentionally push the tube of the supply channel 87 or apply excessive acceleration or impact to the joint 88. At this time, the liquid-gas interface of the liquid inside the liquid discharge head 20 is located further back from the nozzle 21N than during printing, so even if the liquid-gas interface is slightly displaced towards the nozzle 21N, the liquid will not drip from the nozzle 21N.

[0146] <Suppression of liquid dripping when the power is off> Next, in the second embodiment, the head replacement operation performed with the liquid dispensing device 11 powered off will be described.

[0147] When the power is off, the operator manually performs the same operations as the liquid drip suppression control. The operator manually drives the pump 47, the first valve 38, the second valve 40, and the switching mechanism 48. Since the first valve 38 and the second valve 40 are normally closed valves, they are closed when the power is off. Therefore, the supply passage 87 is closed. The operator operates the control units 38A and 40A to switch the first valve 38 and the second valve 40 from the closed state to the open state.

[0148] As the liquid discharge head 20 moves to the replacement position PH2, the head difference between the liquid at the standard position in the first and second storage chambers 62 and 68 and the liquid meniscus located on the nozzle surface 21A of the liquid discharge head 20 increases further. In accordance with this increase in head difference, the negative pressure acting on the liquid in the nozzle 21N increases. As a result, the liquid meniscus in the liquid discharge head 20 moves further upstream (towards the back of the nozzle 21N).

[0149] Next, the operator manually depressurizes the first storage chamber 62 and the second storage chamber 68. First, the operator uses the control unit 74 to switch the cam of the switching mechanism 48. Switching the cam opens the first selector valve 73a, the fifth selector valve 73e, the eighth selector valve 73h, the tenth selector valve 73j, and the eleventh selector valve 73k, and closes the other selector valves. In this state, the operator operates the control unit 47A to drive the pump 47 in reverse. As a result, air in the first storage chamber 62 is discharged via the connecting passage 52 and the atmospheric release passage 50, and the pressure in the first storage chamber 62 decreases. At the same time, air in the second storage chamber 68 is discharged via the connecting passage 52 and the pressurizing passage 51, and the pressure in the second storage chamber 68 decreases.

[0150] As the first storage chamber 62 and the second storage chamber 68 are depressurized, the negative pressure acting on the liquid at the liquid meniscus within the liquid discharge head 20 increases further by the amount of the depressurization. As a result, the liquid meniscus within the liquid discharge head 20 moves further upstream. An air region is created in the part of the liquid discharge head 20 that includes the nozzle 21N. The operator reverses the pump 47 by the required amount of rotation and stops the operation by the control unit 47A. In this way, the storage units 33 and 35 are depressurized.

[0151] Furthermore, the operator uses the control unit 74 to switch the cam of the switching mechanism 48. By switching the cam, the operator selects a switching position that closes the first selector valve 73a, the fifth selector valve 73e, the eighth selector valve 73h, the tenth selector valve 73j, and the eleventh selector valve 73k. This maintains the reduced pressure in the storage sections 33 and 35.

[0152] <Effects of the second embodiment> According to the second embodiment, in addition to obtaining the same effects as in the first embodiment (1) to (4), the following effects can be obtained.

[0153] (8) The liquid discharge device 11 includes valves 38 and 40 provided in the middle of the supply channel 87 that can open and close the supply channel 87, and a control unit 100 that can control the opening and closing of valves 38 and 40. Valves 38 and 40 are configured to be manually opened and closed when the power is off. With this configuration, even when the supply channel 87 is removed from the liquid discharge head 20 when the power is off, negative pressure can be applied to the connection part 89 of the joint part 88 by manually opening valves 38 and 40. Therefore, dripping when the supply channel 87 is removed from the liquid discharge head 20 can be suppressed.

[0154] (9) The system further includes a pressure reducing section 76 capable of reducing the pressure in the storage section 86, and a pressure maintenance section 77 capable of maintaining the pressure reduced by the pressure reducing section 76. The pressure reducing section 76 and the pressure maintenance section 77 are configured to be controllable by the control unit 100 and to be manually operable. With this configuration, when the supply channel 87 is removed from the liquid discharge head 20, negative pressure can be applied to the connection section 89 of the joint section 88.

[0155] 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. In the first embodiment described above, the control unit 100 drives the variable volume mechanism 58 in a direction that increases the volume of the liquid chamber 41, so that the liquid is drawn into the liquid chamber 41 only once. In other words, the configuration may only perform the process in step S11.

[0156] In the first embodiment described above, a flow valve for opening and closing the supply flow path 87 may be provided at a position between the liquid chamber 41 and the joint 88 of the variable-volume mechanism 58. The flow valve may be opened when increasing the volume of the liquid chamber 41 to draw the liquid in the liquid discharge head 20 upstream (towards the joint 88), and the flow valve may be closed when sending the liquid drawn into the liquid chamber 41 to the first storage chamber 62.

[0157] In the first embodiment, the first valve 38 and the second valve 40 may be in an open state when the joint portion 88 is removed from the connected portion 22 of the liquid discharge head 20. In the first embodiment, the first storage chamber 62 and the second storage chamber 68 may be depressurized when replacing the head, similar to the second embodiment. This configuration makes it even less likely for liquid to drip from the connection part 89 when removing the joint part 88 from the liquid discharge head 20.

[0158] In the second embodiment and the above-described modification, when replacing the head, only one of the first storage chamber 62 and the second storage chamber 68 may be depressurized. In the second embodiment, when replacing the head, only one of the first valve 38 and the second valve 40 may be left open.

[0159] In the second embodiment described above, the configuration may be such that neither the first storage chamber 62 nor the second storage chamber 68 is depressurized when the head is replaced. The replacement position PH2 of the liquid ejection head 20 may be the same position as the cap position where the head unit 21 is capped by the cap 116. Also, the liquid ejection head 20 does not have to be a lift-up type that moves to a different height position than the position during printing and while waiting to print when it is replaced.

[0160] Pumps 47 and 75 are not limited to tube pumps, but may be other types of pumps. For example, they may be diaphragm pumps or gear pumps. The liquid supply unit 81 is not limited to being located inside the main body 12 of the liquid dispensing device 11, but may also be an external unit connected to the main body 12 via a tube or the like.

[0161] The locking portion 91 and the locked portion 88A are not limited to the locking portion 91 being a protrusion and the locked portion 88A being a recess; they may be reversed. The same applies to the locking portion 91 and the locked portion 92A; the protrusion and recess may be reversed.

[0162] • In the retaining portion 90, a locking portion 91 that engages with the joint portion 88 and a locking portion 91 that engages with the cap 92 may be provided separately. The locking portion 91 may be a snap-fit.

[0163] The joint portion 88 does not necessarily have a locking portion 88A. The locking portion 91 may have a regulating surface that abuts against the side surface of the joint portion 88 and restricts the joint portion 88 to a holding position. The first storage section 33 or the second storage section 35 may have a window that allows the user to visually check the liquid level.

[0164] The storage section 86 does not have to be divided into two parts, the first storage section 33 and the second storage section 35; it may be a single unit. The storage section 86 may be a liquid container 82. In other words, in the above embodiment, the first storage section 33 and the second storage section 35 may be eliminated. The liquid container 82 mounted on the mounting section 83 may be connected to the supply channel 87 as the storage section.

[0165] • In the liquid circulation, the liquid from the liquid discharge head 20 may be returned to the second storage chamber 68 through the return channel 39. The supply channel 87 is not limited to a liquid circulation type channel including a feed channel 37 and a return channel 39, but may also be a supply channel 87 that includes only one channel for each color corresponding to the feed channel 37.

[0166] The liquid container 82 is not limited to a cartridge such as an ink cartridge, but may be a tank configured to be detachable from the mounting section 83. The storage section 86 may be a tank that is not detachable from the device body 12 and is refilled with liquid by the user.

[0167] The opening 12D from which the liquid discharge head 20 is removed during replacement may be formed on the side of the device body. For example, the liquid discharge head 20 may be replaced through an opening on the back of the device body 12.

[0168] The position of the retaining portion 90 is not limited to above the mounting portion 83, but may also be to the side of the mounting portion 83. The liquid ejection device 11 may be a serial printer. In this case, the serial liquid ejection head 20 has a head section 21 and a carriage that is movable in the width direction X on which the head section 21 is provided. A coupling section 88 connected to one end of the supply channel 87 is connected to a connected section 22 provided on the carriage.

[0169] The liquid dispensing device may be an inkjet type printing device. The printing device may also include a holding part 90 for supporting the joint part 88, or it may also include a cap 92. Furthermore, the printing device may perform liquid drip suppression control.

[0170] The liquid dispensing device 11 is not limited to a multifunction printer. The liquid dispensing device 11 does not need to include an image reading unit 13. The liquid ejection device 11 may be a liquid ejection device that ejects liquids other than ink. Examples include pre-treatment liquids and post-treatment liquids for printing. The state of the liquid ejected from the liquid ejection device as minute droplets may include granular, teardrop-shaped, and thread-like forms. The liquid referred to here may be any material that can be ejected from the liquid ejection 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.

[0171] The technical concepts and their effects derived from the above embodiments and modifications are described below. (A) The liquid dispensing device comprises a liquid dispensing head capable of dispensing liquid, a storage section provided at a lower position than the liquid dispensing head and capable of storing the liquid supplied to the liquid dispensing head, a supply channel provided with a joint that can be attached to and detached from the liquid dispensing head and capable of communicating the liquid dispensing head and the storage section, and a holding section capable of holding the joint when it has been removed from the liquid dispensing head, wherein the joint has a connecting portion that is connected to the liquid dispensing head, and the holding section is configured to hold the joint with the connecting portion facing upward.

[0172] With this configuration, even if the fitting of the supply channel is removed from the liquid discharge head, dripping of liquid from the connection part of the fitting can be suppressed. (B) The liquid dispensing device described above may further include a cap that is detachably provided on the holding portion and detachably attached to the connection portion of the joint portion removed from the liquid dispensing head.

[0173] This configuration allows for better suppression of liquid dripping from the connection point. (C) In the above liquid dispensing device, the holding portion may be configured as a bottomed box with an opening at the top.

[0174] This configuration prevents liquid from dripping from the connection point and adhering to other parts. (D) The liquid dispensing device further comprises a valve provided in the middle of the supply channel and capable of opening and closing the supply channel, and a control unit capable of controlling the opening and closing of the valve, wherein the valve may be configured to be manually opened and closed when the power is turned off.

[0175] With this configuration, even when the supply channel is removed from the liquid discharge head with the power off, negative pressure can be applied to the connection point of the fitting by manually opening the valve. Therefore, dripping when the supply channel is removed from the liquid discharge head can be suppressed.

[0176] (E) In the liquid dispensing device described above, the valve may be a normally closed valve that automatically closes the supply channel when the power is turned off. This configuration prevents liquid from continuing to overflow from the nozzle in unforeseen circumstances when the power is turned off.

[0177] (F) The liquid dispensing device further comprises a depressurization unit capable of reducing the pressure of the space within the storage unit, and a depressurization maintenance unit capable of maintaining the depressurization by the depressurization unit, wherein the depressurization unit and the depressurization maintenance unit are configured to be controllable by the control unit and to be manually operable.

[0178] With this configuration, when the supply channel is removed from the liquid discharge head, negative pressure can be applied to the connection point of the joint. (G) The liquid dispensing device further comprises a drive unit, the supply channel has a flexible portion having flexibility in at least a part thereof, the drive unit displaces the flexible portion in a direction that increases the volume of the supply channel and is capable of maintaining the displaced state of the flexible portion, and the drive unit may be configured to be controllable by the control unit and to be manually operable.

[0179] This configuration allows for greater negative pressure to be applied to the connection point of the joint when the supply channel is removed from the liquid discharge head. (H) The liquid dispensing device further comprises a mounting portion on which a liquid container for containing the liquid to be supplied to the storage portion is detachably provided, the liquid dispensing head has a connected portion that can be connected to the connecting portion of the joint portion, and the holding portion may be provided at a position closer to the base end, which is one end of the supply channel on the storage portion side, than to the connected portion of the liquid dispensing head.

[0180] This configuration makes it easier to hold the fitting removed from the liquid discharge head in the holding unit. For example, when an operator places the removed fitting on the holding unit, it is less likely to cause stress to the supply flow path due to pulling, bending, or twisting. [Explanation of Symbols]

[0181] 11...Liquid dispensing device, 12...Device body, 12A...Recess, 12C...Frame, 12D...Opening, 12F...Frame section, 13...Image reading section, 13A...Reading section, 13B...Automatic feeding section, 13C...Document feeding tray, 13D...Document output tray, 14...Media storage section, 15...Feeding section, 16...Transportation path, 17...Transportation section, 18...Stacker, 18A...Output tray, 19...Display section, 19A...Operation section, 20...Liquid dispensing head, 21...Head section, 21A...Nozzle surface, 21N...Nozzle, 22...Connected section, 23...Feeding roller, 24...Separation section, 26...Transport roller, 27...Transportation belt, 2 7a...Conveying surface, 28...Roller, 29...Storage chamber, 30...Outlet section, 31...Outlet valve, 33...First storage section, 34...Connecting passage, 35...Second storage section, 36...One-way valve, 37...Feed passage constituting the supply passage, 38...First valve as an example of a valve, 39...Return passage constituting the supply passage, 40...Second valve as an example of a valve, 41...Liquid chamber, 42...Flexible section, 44...First passage, 45...Second passage, 46...Filter, 47...Pump, 47A...Operating section, 48...Switching mechanism, 49...Pressure sensor, 50...Atmospheric release passage, 51...Pressurized passage, 52...Connecting passage, 53...Air chamber, 54... 55...Spring, 57...Air passage, 58...Variable volume mechanism, 59...Drive unit, 60...Inlet unit, 61...Inlet valve, 62...First storage chamber, 63...Liquid level detection unit, 64...First gas-liquid separation membrane, 66...First liquid level, 68...Second storage chamber, 69...Second gas-liquid separation membrane, 70...Second liquid level, 72...Narrow tube section, 73a...First selector valve, 73b...Second selector valve, 73c...Third selector valve, 73d...Fourth selector valve, 73e...Fifth selector valve, 73f...Sixth selector valve, 73g...Seventh selector valve, 73h...Eighth selector valve, 73i...Ninth selector valve, 73j...Tenth selector valve, 73k...Eleventh selector valve, 74...Operating unit, 75...Pump 75A...Operation section, 76...Depressurization section, 77...Depressurization maintenance section, 80...Liquid supply unit, 81...Liquid supply section, 82...Liquid container, 83...Mounting section, 84...Needle section, 85...Supply mechanism, 86...Storage section, 87...Supply channel, 87A...Variable section, 87B...Fixed section, 87E...Base end, 88...Joint section, 88A...Locking section, 89...Connection section, 89A...Tube section, 90...Holding section, 90A...Opening, 90B...Mounting surface, 92...Cap, 92A...Locking section, 95...Maintenance section, 100...Control unit, 110...Movement mechanism, 111...Rack, 112...Drive gear, 113...Motor, 115...Cap unit,116…Cap, 120…Movement mechanism, 121…Rack, 122…Drive gear, 123…Motor, M…Media, PH1…Printing position, PH2…Replacement position, HL…Opening, X…Depth direction (width direction), Z…Vertical direction, Dc…Conveying direction.

Claims

1. A liquid dispensing head capable of dispensing liquid, A storage section is provided at a lower position than the liquid discharge head and is capable of storing the liquid supplied to the liquid discharge head, A detachable joint is provided with the liquid discharge head, and a supply channel is provided that can connect the liquid discharge head and the storage section. It comprises a retaining part capable of holding the joint part removed from the liquid discharge head, The aforementioned joint portion has a connecting portion that is connected to the liquid discharge head, The holding portion is detachably provided, and the connecting portion of the joint portion removed from the liquid discharge head is further provided with a detachable cap, The liquid dispensing device is characterized in that the holding portion is configured to hold the joint portion with the connecting portion facing upward.

2. A liquid dispensing head capable of dispensing liquid, A storage section is provided at a lower position than the liquid discharge head and is capable of storing the liquid supplied to the liquid discharge head, A detachable joint is provided with the liquid discharge head, and a supply channel is provided that can connect the liquid discharge head and the storage section. It comprises a retaining part capable of holding the joint part removed from the liquid discharge head, The aforementioned joint portion has a connecting portion that is connected to the liquid discharge head, The liquid dispensing device is characterized in that the holding portion is configured as a bottomed box with an open top, and is configured to hold the joint portion with the connecting portion facing upwards.

3. A liquid dispensing head capable of dispensing liquid, A storage section is provided at a lower position than the liquid discharge head and is capable of storing the liquid supplied to the liquid discharge head, A detachable joint is provided with the liquid discharge head, and a supply channel is provided that can connect the liquid discharge head and the storage section. A retaining part capable of holding the joint part removed from the liquid discharge head, The device comprises a mounting section on which a liquid container for containing the liquid to be supplied to the storage section is detachably provided, The aforementioned joint portion has a connecting portion that is connected to the liquid discharge head, The liquid discharge head has a connected portion that can be connected to the connecting portion of the joint portion, The liquid dispensing device is characterized in that the holding portion is configured to hold the joint portion with the connecting portion facing upward, and is provided at a position closer to the base end, which is one end of the supply channel on the storage portion side, than to the connected portion of the liquid dispensing head.

4. A liquid dispensing head capable of dispensing liquid, A storage section is provided at a lower position than the liquid discharge head and is capable of storing the liquid supplied to the liquid discharge head, A detachable joint is provided with the liquid discharge head, and a supply channel is provided that can connect the liquid discharge head and the storage section. A retaining part capable of holding the joint part removed from the liquid discharge head, A valve is provided in the middle of the supply channel and is capable of opening and closing the supply channel, The system comprises a control unit capable of controlling the opening and closing of the valve, The aforementioned joint portion has a connecting portion that is connected to the liquid discharge head, The holding portion is configured to hold the joint portion with the connecting portion facing upwards. The liquid dispensing device is characterized in that the valve is configured to be manually opened and closed when the power is turned off.

5. The liquid dispensing device according to claim 4, characterized in that the valve is a normally closed valve that automatically closes the supply channel when the power is turned off.

6. A depressurization section capable of reducing the pressure in the space within the storage section, The system further comprises a pressure maintenance unit capable of maintaining the pressure reduction by the aforementioned pressure reduction unit, The liquid dispensing device according to claim 4 or 5, characterized in that the pressure reduction unit and the pressure reduction maintenance unit are configured to be controllable by the control unit and to be manually operable.

7. It is further equipped with a drive unit, The supply channel has a flexible portion that is flexible in at least part of it, The drive unit displaces the flexible portion in a direction that increases the volume of the supply channel, and is capable of maintaining the displaced state of the flexible portion. The liquid dispensing device according to claim 4 or 5, characterized in that the drive unit is configured to be controllable by the control unit and to be manually operable.

8. A liquid dispensing head capable of dispensing liquid, A guide portion that movably supports the liquid dispensing head, A storage section is provided at a lower position than the liquid discharge head and is capable of storing the liquid supplied to the liquid discharge head, A detachable joint is provided with the liquid discharge head, and a supply channel is provided that can connect the liquid discharge head and the storage section. It comprises a retaining part capable of holding the joint part removed from the liquid discharge head supported by the guide part, The aforementioned joint portion has a connecting portion that is connected to the liquid discharge head, The liquid dispensing device is characterized in that the holding part holds the joint part with the connecting part facing upward.

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