Liquid supply device, liquid supply method, and image recording device

Abstract

To reduce a gap of liquid amounts flowing into a head through a plurality of flow channels by suction.SOLUTION: An ink supply part 50 includes: a plurality of cartridges 51 for storing ink; a plurality of sub tanks 53 which are in lower positions than the cartridges 51 and are flexible; a plurality of valves 52 which open / close an ink flow channel 56 connecting the cartridges 51 and sub tanks 53; a head 42 through which the ink can distribute from the sub tanks 53 through the ink flow channel 57; a pump 85 which applies a suction pressure to the ink flow channel 57 from a head 42 side; a sensor 54; and a control part 60. In initial introduction of ink, the control part 60 executes operation for opening the valves 52 (S54), operation for closing the valves 52 in response to reception of a sensor signal indicating an ink amount in the sub tank 53 is more than a threshold from the sensor 54 (S56), and operation for sucking for a predetermined time by the pump 85 (S57).SELECTED DRAWING: Figure 8

Description

[Technical field]

[0001] The present invention relates to a liquid supplying device that supplies liquid from a reservoir to a head, a liquid supplying method, and an image recording apparatus equipped with the liquid supplying device. [Background technology]

[0002] There is known an image recording device that includes a head and a carriage on which the head is mounted, and that ejects ink from the nozzles of the head when the carriage moves in a predetermined direction. The image recording device has an ink supply device that supplies ink from an ink storage unit to the head. When there are multiple types of ink, the ink supply device has multiple ink flow paths between the multiple storage units and the head.

[0003] Patent Document 1 describes a printer equipped with a head having four types of nozzles that eject four colors of ink, and a cap that collectively covers the four types of nozzles. This printer supplies the four colors of ink from four cartridges to four sub-tanks, and supplies the four colors of ink from the four sub-tanks to the head using four ink flow paths. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2020-011485 A Summary of the Invention [Problem to be solved by the invention]

[0005] In the printer described in Patent Document 1, a so-called initial introduction is performed in which four colors of ink are initially introduced into each of the four ink flow paths by applying suction pressure from the head side. In this printer, ink is supplied using a head difference between the cartridge and the subtank. Therefore, ink flows from the cartridge into the subtank in an amount equal to the amount of ink that flows from the subtank to the head side due to suction pressure.

[0006] There may be a difference in resistance between the four ink flow paths connecting the four subtanks and the head. In such a case, when the initial introduction described above is performed, the amount of ink flowing from the subtank to the head side through the flow path with the small flow path resistance increases, and the amount of ink flowing from the subtank to the head side through the flow path with the large flow path resistance decreases. In this way, a difference occurs in the amount of ink introduced between the multiple ink flow paths. For this reason, for example, if the suction time is set so that a sufficient amount of ink flows to the head side even through the flow path with the large flow path resistance, an excessive amount of ink will flow to the head side through the flow path with the small flow path resistance.

[0007] The present invention has been made in consideration of the above circumstances, and an object of the present invention is to provide a means for reducing the difference in the amount of liquid flowing to a head through a plurality of flow paths by suction. [Means for solving the problem]

[0008] (1) A liquid supply device according to the present invention includes a first storage section for storing liquid, a second storage section for storing liquid, a first tank located lower than the first storage section and flexible, a second tank located lower than the second storage section and flexible, a first valve for opening and closing a flow path connecting the first storage section and the first tank, a second valve for opening and closing a flow path connecting the second storage section and the second tank, a head through which liquid can flow from the first tank through the first flow path and through which liquid can flow from the second tank through the second flow path, a suction mechanism that, when driven, applies suction pressure from the head to the first flow path and the second flow path, a first sensor, a second sensor, and a controller. In response to receiving a suction instruction, the controller performs a valve opening operation to open the first valve and the second valve, and after performing the valve opening operation, performs a valve closing operation to close the first valve in response to receiving a first signal from the first sensor indicating that the amount of liquid in the first tank is equal to or greater than a first threshold, and to close the second valve in response to receiving a second signal from the second sensor indicating that the amount of liquid in the second tank is equal to or greater than a second threshold, and after performing the valve closing operation, performs a suction operation to drive the suction mechanism for a predetermined period of time.

[0009] According to the above liquid supply device, in a liquid supply device that performs suction to introduce liquid into multiple flow paths connecting multiple storage sections and a head, after a predetermined amount of liquid is supplied to each tank, the supply of liquid from each storage section to each tank is stopped and the suction mechanism is driven, thereby reducing the difference in the amount of liquid flowing to the head through the multiple flow paths by suction.

[0010] (2) Preferably, the controller executes the valve opening operation after executing the suction operation.

[0011] (3) Preferably, the liquid supply device further includes a third sensor and a fourth sensor, and the controller opens the first valve in response to receiving a third signal from the third sensor indicating that the amount of liquid in the first tank is less than a third threshold, and opens the second valve in response to receiving a fourth signal from the fourth sensor indicating that the amount of liquid in the second tank is less than a fourth threshold.

[0012] (4) Preferably, the controller, in response to receiving the suction instruction, repeatedly executes the valve opening operation, the valve closing operation, and the suction operation a predetermined number of times.

[0013] (5) Preferably, after the controller performs the valve opening operation, the valve closing operation, and the suction operation a first number of times among the predetermined number of times, the controller keeps the first valve closed in the valve opening operation.

[0014] (6) Preferably, the controller executes the valve opening operation after repeatedly executing the valve opening operation, the valve closing operation, and the suction operation the predetermined number of times.

[0015] (7) Preferably, the suction mechanism is driven for the predetermined time to suck in a predetermined amount, and the predetermined amount is greater than a capacity of the first tank and a capacity of the second tank.

[0016] (8) Preferably, the liquid supplying device further includes a third sensor and a fourth sensor, and the controller executes a recording operation of discharging liquid from the head with the first valve and the second valve closed, opens the first valve in response to receiving a third signal from the third sensor indicating that the amount of liquid in the first tank is less than a third threshold, executes a first valve opening / closing operation to close the first valve in response to receiving the first signal from the first sensor after receiving the third signal, opens the second valve in response to receiving a fourth signal from the fourth sensor indicating that the amount of liquid in the second tank is less than a fourth threshold, and executes a second valve opening / closing operation to close the second valve in response to receiving the second signal from the second sensor after receiving the fourth signal, and does not execute the first valve opening / closing operation and the second valve opening / closing operation in response to receiving the suction instruction until the suction operation is completed.

[0017] (9) An image recording apparatus according to the present invention includes any one of the liquid supplying devices described above, and a transport section for transporting a recording medium on which the liquid ejected from the head lands.

[0018] (10) A liquid supplying method according to the present invention is a liquid supplying method that uses a first storage section for storing liquid, a second storage section for storing liquid, a first tank located at a lower position than the first storage section and having flexibility, a second tank located at a lower position than the second storage section and having flexibility, and a head through which liquid can flow from the first tank through a first flow path, and through which liquid can flow from the second tank through a second flow path. The liquid supply method includes a valve opening step of opening a first valve that opens and closes a flow path connecting the first storage portion and the first tank in response to receiving a suction instruction, and a second valve that opens and closes a flow path connecting the second storage portion and the second tank, after the valve opening step, a valve closing step of closing the first valve in response to receiving a first signal from a first sensor indicating that the amount of liquid in the first tank is equal to or greater than a first threshold, and closing the second valve in response to receiving a second signal from a second sensor indicating that the amount of liquid in the second tank is equal to or greater than a second threshold, and a suction step of driving a suction mechanism that is driven to apply suction pressure to the first flow path and the second flow path from the head side for a predetermined period of time after the valve closing step. Effect of the Invention

[0019] According to the present invention, the difference in the amount of liquid flowing to the head through a plurality of flow paths by suction is reduced. [Brief description of the drawings]

[0020] [Figure 1] FIG. 1 is a schematic diagram showing the internal configuration of a printer 10 according to an embodiment of the present invention. [Diagram 2] FIG. 2 is a diagram showing the movement range of the carriage 41. As shown in FIG. [Diagram 3] FIG. 3 is a block diagram showing the configuration of the control unit 60 and elements connected to the control unit 60. As shown in FIG. [Figure 4] FIG. 4 is a schematic diagram showing the configuration of the ink supply unit 50. As shown in FIG. [Diagram 5]5A and 5B are diagrams showing the configuration of the periphery of the head 42, in which FIG. 5A is a perspective view of the periphery of the head 42, and FIG. [Figure 6] FIG. 6 is a flowchart of the automatic ink supply process performed by the control unit 60. [Figure 7] FIG. 7 is a flowchart of the image recording process by the control unit 60. [Figure 8] FIG. 8 is a flowchart of the initial installation process performed by the control unit 60. [Figure 9] FIG. 9 is a flowchart of the initial introduction process by the control unit 60 according to the modified example. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0021] Hereinafter, a printer 10 (an example of an image recording device) and an ink supply unit 50 (an example of a liquid supply device) according to an embodiment of the present invention will be described. Note that the embodiment described below is merely an example of the present invention, and it goes without saying that the embodiment of the present invention can be appropriately modified within the scope of the present invention. In the following description, the direction is expressed as the progress from the starting point of the arrow to the end point, and the direction is expressed as the movement on the line connecting the starting point and the end point of the arrow. In addition, the up-down direction 7 is defined based on the state in which the printer 10 is installed and ready for use (the state in FIG. 1), the front-rear direction 8 is defined with the surface where the discharge port 13 is provided as the front surface, and the left-right direction 9 is defined when the printer 10 is viewed from the front. The up-down direction 7, the front-rear direction 8, and the left-right direction 9 are mutually perpendicular.

[0022] [Overall configuration of Printer 10] The printer 10 shown in Fig. 1 is an image recording device that records an image on a sheet S (an example of a recording medium) using an inkjet recording method. The sheet S is a long piece of paper wound in a roll. To load the sheet S into the printer 10, a through hole is formed in the center of the winding of the sheet S. The recording medium may be sticker paper, fanfold paper, cut paper, cloth, or the like.

[0023] The printer 10 has a housing 11 that is roughly rectangular. The housing 11 is sized to be able to be placed on a table, a floor, a rack, or the like. A slit-shaped discharge opening 13 extending in the left-right direction 9 is located in a front wall 12 of the housing 11. A sheet S on which an image is recorded by the printer 10 is discharged from the discharge opening 13. The discharged sheet S is taken up, for example, by a winding device (not shown) attached to the printer 10.

[0024] As shown in FIG. 1, the printer 10 includes a holder 21, a tensioner 22, a pair of conveying rollers 23, a pair of discharge rollers 24, a platen 25, a cartridge holder 26, a carriage 41, a head 42, and an ink supply unit 50 (see FIG. 4) in a housing 11. The head 42 is mounted on the carriage 41. A cartridge 51 that stores ink (an example of liquid) is attached to the cartridge holder 26. As shown in FIG. 2, the printer 10 further includes two guide rails 37, 38, and a cap 81 in the housing 11. As shown in FIG. 3, the printer 10 further includes a control unit 60, a holder drive motor 71, a conveying motor 72, a carriage drive motor 73, and a cap drive motor 74 in the housing 11. The printer 10 may further include a wipe unit, various motors, various sensors, and the like, in addition to the above-mentioned elements.

[0025] [Sheet S transport mechanism] A pair of side frames (not shown) extending in the up-down direction 7 and the front-rear direction 8 are positioned inside the housing 11. The holder 21 has a rotating shaft 31 supporting the sheet S. The rotating shaft 31 extends in the left-right direction 9, and both ends of the rotating shaft 31 are fixed to the side frames. Power of a holder drive motor 71 (see FIG. 3) is transmitted to the rotating shaft 31. This power rotates the holder 21 in the circumferential direction of the rotating shaft 31. In FIG. 1, the rotation direction of the holder 21 is counterclockwise. The rotation of the holder 21 also rotates the roll body supported by the holder 21. The sheet S is pulled upward from the rear end of the roll body by the rotation of the conveying roller pair 23 and the discharge roller pair 24, and is guided to the tensioner 22.

[0026] The tensioner 22, the conveying roller pair 23, and the discharge roller pair 24 each extend in the left-right direction 9 between the side frames, and are attached to be rotatable in the circumferential direction of a rotation shaft parallel to the left-right direction 9. A rearward biasing force is applied to the tensioner 22 by a biasing member such as a spring. The tensioner 22 comes into contact with the sheet S pulled out from the roll body, and guides the sheet S so as to curve forward.

[0027] The conveying roller pair 23 has a drive roller 32 and a pinch roller 33, and is located in front of the tensioner 22. The discharge roller pair 24 has a drive roller 34 and a pinch roller 35, and is located further in front of the conveying roller pair 23. The lower end positions of the drive rollers 32, 34 roughly coincide with the upper end position of the tensioner 22 in the up-down direction 7. The pinch roller 33 abuts on the drive roller 32 from below. The pinch roller 35 abuts on the drive roller 34 from below.

[0028] The power of a conveying motor 72 (see FIG. 3) is transmitted to the driving rollers 32, 34. The driving rollers 32, 34 rotate due to this power. As a result, the driving rollers 32, 34 convey the sheet S in a conveying direction 6 while nipping it between the driving rollers 32, 34 and the pinch rollers 33, 35. In this embodiment, the conveying direction 6 is forward. The conveying motor 72, the conveying roller pair 23, and the discharge roller pair 24 function as a conveying unit that conveys the sheet S on which the ink ejected from the head 42 lands.

[0029] [Platen 25] The platen 25 is attached to the side frames at a position between the pair of conveying rollers 23 and the pair of discharge rollers 24 in the front-rear direction 8. The platen 25 extends in the left-right direction 9 between the side frames and has a support surface 36 for the sheet S that expands in the front-rear direction 8 and the left-right direction 9. The support surface 36 is the upper end surface of the platen 25. The vertical position of the support surface 36 roughly coincides with the upper end position of the tensioner 22. The platen 25 may be an adhesive platen that adhesively attaches the sheet S to the support surface 36.

[0030] [Carriage 41 and Head 42] As shown in FIG. 2, the guide rails 37, 38 extend parallel to each other in the left-right direction 9. The positions of the guide rails 37, 38 in the up-down direction 7 are the same. The guide rail 38 is located behind the guide rail 37 in the front-rear direction. Both ends of the guide rails 37, 38 are fixed to side frames. The carriage 41 is supported by the guide rails 37, 38. The power of a carriage drive motor 73 (see FIG. 3) is transmitted to a carriage drive mechanism (not shown). The carriage 41 moves in the left-right direction 9 while supported by the guide rails 37, 38 by the action of the carriage drive mechanism.

[0031] As shown in FIG. 1, the head 42 is mounted on a carriage 41. The lower surface of the head 42 is referred to as a nozzle surface 43. A plurality of nozzles 44 that eject ink are positioned on the nozzle surface 43. A cartridge 51 mounted on the cartridge holder 26 and the head 42 are connected via an ink supply unit 50 (see FIG. 4). Ink stored in the cartridge 51 is supplied to the head 42 via the ink supply unit 50. While the carriage 41 is moving in the left-right direction 9, the ink supplied to the head 42 is ejected from the nozzles 44. In this way, an image is recorded on the sheet S.

[0032] [Control unit 60] As shown in FIG. 3, the control unit 60 has a CPU 61, a ROM 62, a RAM 63, an EEPROM 64, and an ASIC 65. The ROM 62 stores various data and the like necessary for the operation of the control unit 60. The RAM 63 is a working memory for the CPU 61. The EEPROM 64 stores a control program and the like executed by the CPU 61. Before the printer 10 executes image recording, the control program stored in the EEPROM 64 is copied to the RAM 63. The CPU 61 executes the control program stored in the RAM 63. As a result, the control unit 60 executes an automatic ink supply process, an image recording process, and an initial installation process, which will be described later. The control unit 60 is an example of a controller.

[0033] The control unit 60 is electrically connected to the holder driving motor 71, the transport motor 72, the carriage driving motor 73, the cap driving motor 74, the lifting member driving motor 75, the pump driving motor 76, and the head 42 via the ASIC 65. The holder driving motor 71, the transport motor 72, the carriage driving motor 73, the cap driving motor 74, the lifting member driving motor 75, and the pump driving motor 76 rotate and generate power under the control of the control unit 60. The head 42 ejects ink onto the sheet S transported on the platen 25 under the control of the control unit 60.

[0034] The holder 21 rotates by the power from the holder drive motor 71. The drive rollers 32, 34 rotate by the power from the transport motor 72. The sheet S is transported in the transport direction 6 by the power from the transport motor 72. The carriage 41 moves in the left-right direction 9 by the power from the carriage drive motor 73. The cap 81 moves in the up-down direction 7 between a relatively high covered position and a relatively low separated position by the power from the cap drive motor 74. The lifting member 106 (see FIG. 5(B); details will be described later) moves in the up-down direction 7 between a relatively high abutment position and a relatively low non-abutment position by the power from the lifting member drive motor 75. The pump 85 (see FIG. 4) is driven by the power from the pump drive motor 76, and applies suction pressure to a flow path connected to the pump 85. In addition, some of the holder drive motor 71, the transport motor 72, the carriage drive motor 73, the cap drive motor 74, the lifting member drive motor 75, and the pump drive motor 76 may be realized by a common motor.

[0035] [Carriage 41 movement range and cap 81] As shown in FIG. 2, the platen 25 has a shape that is elongated in the left-right direction 9, and is located below the carriage 41 in the up-down direction 7 (see FIG. 1). The left end of the platen 25 is located near the left ends of the guide rails 37, 38 in the left-right direction 9. The right end of the platen 25 is located to the right of the center of the guide rails 37, 38 in the left-right direction 9. The cap 81 is located to the right of the platen 25 in the left-right direction 9. While the printer 10 is performing image recording, the carriage 41 moves in the left-right direction 9 within the range of the platen 25. While the printer 10 is not performing image recording, the carriage 41 is located in a position where the head 42 faces the cap 81 (hereinafter referred to as the standby position).

[0036] As shown in FIG. 4, the cap 81 has a nozzle cap 82 that covers the nozzle surface 43 of the head 42, and an exhaust cap 83 that covers the exhaust port surface 46 of the exhaust unit 45 (details will be described later). When the carriage 41 is located at the standby position, the cap 81 is located at the covering position. At this time, the nozzle cap 82 covers the nozzle surface 43 of the head 42, and the exhaust cap 83 covers the exhaust port surface 46 of the exhaust unit 45. When the carriage 41 is located at a position other than the standby position, the cap 81 is located at the separated position. At this time, the nozzle cap 82 does not cover the nozzle surface 43, and the exhaust cap 83 does not cover the exhaust port surface 46. In this way, the cap 81 has the function of covering the nozzle surface 43 and the exhaust port surface 46 while image recording is not being performed.

[0037] [Ink supply unit 50] The ink supply unit 50 of the printer 10 will be described with reference to Fig. 4. Four cartridges 51b, 51c, 51m, and 51y that respectively store black, cyan, magenta, and yellow ink are attached to the cartridge holder 26 (see Fig. 1). The ink supply unit 50 includes cartridges 51b, 51c, 51m, and 51y, four valves 52b, 52c, 52m, and 52y, four sub-tanks 53b, 53c, 53m, and 53y, eight sensors 54b, 54c, 54m, 54y, 55b, 55c, 55m, and 55y, the head 42, a pump 85, and a control unit 60.

[0038] The inks stored in cartridges 51b, 51c, 51m, and 51y are so-called latex inks, and contain pigments, resin particles, and additives. The ink has a viscosity suitable for uniformly dispersing the pigments and resin particles. The pigments give the ink its color. The resin particles are for adhering the pigments to the sheet S, and are, for example, synthetic resins whose glass transition temperature is exceeded by heating with a heater (not shown). Note that the printer 10 is only required to be able to accommodate at least two cartridges and to have at least two sub-tanks.

[0039] Ink flow path 56b connects cartridge 51b and subtank 53b. Ink flow path 56c connects cartridge 51c and subtank 53c. Ink flow path 56m connects cartridge 51m and subtank 53m. Ink flow path 56y connects cartridge 51y and subtank 53y. Ink flow path 57b connects subtank 53b and head 42. Ink flow path 57c connects subtank 53c and head 42. Ink flow path 57m connects subtank 53m and head 42. Ink flow path 57y connects subtank 53y and head 42.

[0040] The ink stored in the cartridge 51b is supplied to the subtank 53b via the ink flow path 56b. The subtank 53b stores the ink supplied from the cartridge 51b. The ink stored in the subtank 53b is supplied to the head 42 via the ink flow path 57b. Similarly, the ink stored in the cartridge 51c is supplied to the head 42 via the ink flow path 56c, the subtank 53c, and the ink flow path 57c. The ink stored in the cartridge 51m is supplied to the head 42 via the ink flow path 56m, the subtank 53m, and the ink flow path 57m. The ink stored in the cartridge 51y is supplied to the head 42 via the ink flow path 56y, the subtank 53y, and the ink flow path 57y.

[0041] The sub-tanks 53b, 53c, 53m, and 53y are flexible. The outer shapes of the sub-tanks 53b, 53c, 53m, and 53y change between a swelled state and a deflated state depending on the amount of ink stored therein. The sub-tank 53b is located at a lower position than the cartridge 51b. Ink is supplied from the cartridge 51b to the sub-tank 53b by a water head difference. Ink is supplied from the sub-tank 53b to the head 42 by initially sucking ink from the head 42 side using the pump 85. Thereafter, the same amount of ink as that ejected from the head 42 is supplied from the sub-tank 53b to the head 42. Ink is also supplied from the sub-tanks 53c, 53m, and 53y to the head 42 in a similar manner.

[0042] In the head 42, black ink can flow from the subtank 53b through an ink flow path 57b, cyan ink can flow from the subtank 53c through an ink flow path 57c, magenta ink can flow from the subtank 53m through an ink flow path 57m, and yellow ink can flow from the subtank 53y through an ink flow path 57y. The ink supply unit 50 has four ink flow paths (ink flow paths for black ink, cyan ink, magenta ink, and yellow ink) between the cartridges 51b, 51c, 51m, and 51y and the head 42.

[0043] The sensors 54b and 55b are located inside or outside the subtank 53b and detect the amount of ink in the subtank 53b. The sensor 54b outputs a sensor signal Sb1 indicating that the amount of ink in the subtank 53b is equal to or greater than a threshold value TH1. The sensor 55b outputs a sensor signal Sb2 indicating that the amount of ink in the subtank 53b is less than a threshold value TH2. Similarly, the sensors 54c, 54m, and 54y output sensor signals Sc1, Sm1, and Sy1 indicating that the amount of ink in the subtanks 53c, 53m, and 53y is equal to or greater than the threshold value TH1, respectively. The sensors 55c, 55m, and 55y output sensor signals Sc2, Sm2, and Sy2 indicating that the amount of ink in the subtanks 53c, 53m, and 53y is less than a threshold value TH2, respectively.

[0044] The sensors 54b, 54c, 54m, 54y, 55b, 55c, 55m, and 55y detect the ink amount in the corresponding subtank 53 by any method. Each sensor may detect the ink amount in the subtank 53 by optically detecting the change in the outer shape of the subtank 53, for example. Each sensor may detect the ink amount in the subtank 53 by a known float method, prism method, or electrode method. The threshold value TH2 used by the sensors 55b, 55c, 55m, and 55y to compare with the ink amount is smaller than the threshold value TH1 used by the sensors 54b, 54c, 54m, and 54y to compare with the ink amount. The threshold values ​​used by the sensors 54b, 54c, 54m, and 54y to compare with the ink amount are not limited to the same value, and the four threshold values ​​may include different values. The threshold values ​​used by the sensors 55b, 55c, 55m, and 55y for comparison with the ink amount are not limited to being the same value, and the four threshold values ​​may include different values.

[0045] The control unit 60 receives sensor signals Sb1, Sc1, Sm1, Sy1, Sb2, Sc2, Sm2, and Sy2 output from the sensors 54b, 54c, 54m, 54y, 55b, 55c, 55m, and 55y, respectively. Based on the input sensor signals, the control unit 60 outputs a control signal Vb for the valve 52b, a control signal Vc for the valve 52c, a control signal Vm for the valve 52m, and a control signal Vy for the valve 52y. The control signals Vb, Vc, Vm, and Vy are binary signals that switch the state of the valve 52 between an open state and a closed state.

[0046] The valve 52b is located on the ink flow path 56b and opens and closes the ink flow path 56b in response to a control signal Vb. The valve 52c is located on the ink flow path 56c and opens and closes the ink flow path 56c in response to a control signal Vc. The valve 52m is located on the ink flow path 56m and opens and closes the ink flow path 56m in response to a control signal Vm. The valve 52y is located on the ink flow path 56y and opens and closes the ink flow path 56y in response to a control signal Vy.

[0047] The ink flow path 57b branches into a portion that reaches the nozzle 44 of the head 42 and a portion that reaches the exhaust port 47 of the exhaust unit 45 on the head 42 side. The internal space of the nozzle cap 82 is connected to a first end of the switching unit 84. The internal space of the exhaust cap 83 is connected to a second end of the switching unit 84. The third end of the switching unit 84 is connected to one end of the pump 85. A waste liquid tank 86 is located on the other end side of the pump 85. The switching unit 84 switches whether the pump 85 is connected to the internal space of the nozzle cap 82 or the internal space of the exhaust cap 83 under the control of the control unit 60. The pump 85 is an example of a suction mechanism that applies suction pressure to the ink flow paths 57c, 57b, 57m, and 57y from the head 42 side.

[0048] [Exhaust section 45] As shown in Fig. 5(A), a buffer 91 having an internal space (not shown) for storing a small amount of ink is located above the head 42. The buffer 91 and the head 42 are connected by a connecting part 92 extending in the up-down direction 7. A rectangular parallelepiped exhaust part 45 is located to the right of the buffer 91. An exhaust port surface 46 is the lower surface of the exhaust part 45, and is located at a higher position than the nozzle surface 43 in the up-down direction 7. Four exhaust ports 47 are located in the exhaust port surface 46. The four exhaust ports 47 are lined up at predetermined intervals in the front-rear direction 8.

[0049] Four ink inlets 93 are located on the upper surface of the buffer 91. The four ink inlets 93 are connected to ink tubes (not shown) that form part of the ink channels 57b, 57c, 57m, and 57y, respectively. Four connecting channels 94 are located at the rear of the connecting portion 92. The four connecting channels 94 extend in the up-down direction 7 and are aligned in the left-right direction 9. Four connection portions 95 are located at the upper portion of the exhaust portion 45. The four ink inlets 93 are connected to the four connecting channels 94 via four ink channels (not shown) in the buffer 91, respectively. The ink that reaches the ink inlets 93 reaches the head 42 via the ink channels in the buffer 91 and the connecting channels 94, and is ejected downward from the nozzles 44 located on the nozzle surface 43.

[0050] The four connecting flow paths 94 are also connected to the four connection parts 95 via four other ink flow paths (not shown) in the buffer 91. The four connection parts 95 are connected to the four exhaust ports 47 via four flow paths through which mainly gas flows, respectively. As shown in FIG. 5B, the flow path connecting the connection parts 95 and the exhaust port 47 has an expanded diameter part 101. A spring 102 and a valve body 103 are located in the internal space of the expanded diameter part 101. The valve body 103 has a main body part 104 and a protruding part 105. The main body part 104 has an outer diameter approximately equal to the inner diameter of the expanded diameter part 101, and is located within the expanded diameter part 101. The protruding part 105 has an outer diameter smaller than the inner diameter of the expanded diameter part 101, and protrudes downward from the expanded diameter part 101 toward the exhaust port 47. The spring 102 is located above the valve body 103 and urges the valve body 103 downward. In a normal state, the main body 104 is pressed against the bottom surface of the enlarged diameter portion 101 by the action of the spring 102, and the four exhaust ports 47 are in a closed state.

[0051] A lifting member 106 is located below the exhaust cap 83. The lifting member 106 has four abutment portions 107. The four abutment portions 107 have an upwardly protruding shape and are lined up at a predetermined interval in the front-rear direction 8. Four through holes are located in the bottom surface of the exhaust cap 83. The four through holes are lined up at a predetermined interval in the front-rear direction 8. The intervals between the four exhaust ports 47, the intervals between the four abutment portions 107, and the intervals between the four through holes of the exhaust cap 83 are all the same. The four abutment portions 107 pass through the four through holes of the exhaust cap 83, respectively.

[0052] As described above, the lifting member 106 can move in the vertical direction 7 between a relatively high abutment position and a relatively low non-abutment position by the power from the lifting member drive motor 75. The lifting member 106 can move in the vertical direction 7 independently of the exhaust cap 83. When the carriage 41 is located at the standby position and the lifting member 106 is located at the abutment position, the four abutment portions 107 abut against the four protrusions 105, respectively. At this time, the four valve bodies 103 move upward against the restoring force of the spring 102 and move away from the bottom surface of the enlarged diameter portion 101. Therefore, the four exhaust ports 47 are in an open state.

[0053] When the carriage 41 is in the standby position and the lifting member 106 is in the non-contact position, the exhaust port 47 is closed. In this state, the internal space of the nozzle cap 82 is connected to the pump 85 by the switching unit 84, and then the pump 85 is driven, so that suction pressure is applied to the ink flow paths 57b, 57c, 57m, and 57y from the head 42 side. As a result, the ink and gas in the ink flow paths 57b, 57c, 57m, and 57y are discharged from the nozzles 44. The ink discharged from the nozzles 44 is stored in the waste liquid tank 86.

[0054] When the carriage 41 is in the standby position and the lifting member 106 is in the abutment position, the exhaust port 47 is in an open state. In this state, the internal space of the exhaust cap 83 is connected to the pump 85 by the switching unit 84, and then the pump 85 is driven, so that suction pressure is applied to the ink flow paths 57b, 57c, 57m, and 57y from the head 42 side. As a result, the ink and gas in the ink flow paths 57b, 57c, 57m, and 57y are exhausted from the exhaust port 47. Mainly gas is exhausted from the exhaust port 47.

[0055] [Operation of control unit 60] The control unit 60 always executes the automatic ink supply process shown in Fig. 6. The control unit 60 executes the initial installation process shown in Fig. 8 when the printer 10 is initially set up. The control unit 60 executes the image recording process shown in Fig. 7 after the initial setup of the printer 10 is complete. The control unit 60 executes the image recording process and the automatic ink supply process in parallel (or in a time-division manner). The control unit 60 stops the automatic ink supply process while the initial installation process is being executed.

[0056] [Automatic ink supply process] The control unit 60 repeatedly executes S11 to S26 in the automatic ink supply process shown in Fig. 6. The control unit 60 judges whether or not it has received a sensor signal Sb2 (a signal indicating that the amount of ink in the subtank 53b is less than a threshold value TH2) from the sensor 55b (S11). In response to the judgment that it has received the sensor signal Sb2 (S11: Yes), the control unit 60 opens the valve 52b (S12). Next, the control unit 60 judges whether or not it has received a sensor signal Sb1 (a signal indicating that the amount of ink in the subtank 53b is equal to or greater than a threshold value TH1) from the sensor 54b (S13). In response to the judgment that it has received the sensor signal Sb1 (S13: Yes), the control unit 60 closes the valve 52b (S14).

[0057] Next, the control unit 60 judges whether a sensor signal Sc2 (a signal indicating that the amount of ink in the subtank 53c is less than the threshold value TH2) has been received from the sensor 55c (S15). In response to the judgment that the sensor signal Sc2 has been received (S15: Yes), the control unit 60 opens the valve 52c (S16). Next, the control unit 60 judges whether a sensor signal Sc1 (a signal indicating that the amount of ink in the subtank 53c is equal to or greater than the threshold value TH1) has been received from the sensor 54c (S17). In response to the judgment that the sensor signal Sc1 has been received (S17: Yes), the control unit 60 closes the valve 52c (S18).

[0058] Next, the control unit 60 judges whether or not it has received a sensor signal Sm2 (a signal indicating that the amount of ink in the subtank 53m is less than the threshold value TH2) from the sensor 55m (S19). In response to the judgment that the sensor signal Sm2 has been received (S19: Yes), the control unit 60 opens the valve 52m (S20). Next, the control unit 60 judges whether or not it has received a sensor signal Sm1 (a signal indicating that the amount of ink in the subtank 53m is equal to or greater than the threshold value TH1) from the sensor 54m (S21). In response to the judgment that the sensor signal Sm1 has been received (S21: Yes), the control unit 60 closes the valve 52m (S22).

[0059] Next, the control unit 60 judges whether a sensor signal Sy2 (a signal indicating that the amount of ink in the subtank 53y is less than the threshold value TH2) has been received from the sensor 55y (S23). In response to the judgment that the sensor signal Sy2 has been received (S23: Yes), the control unit 60 opens the valve 52y (S24). Next, the control unit 60 judges whether a sensor signal Sy1 (a signal indicating that the amount of ink in the subtank 53y is equal to or greater than the threshold value TH1) has been received from the sensor 54y (S25). In response to the judgment that the sensor signal Sy1 has been received (S25: Yes), the control unit 60 closes the valve 52y (S26).

[0060] [Image recording processing] The control unit 60 repeatedly executes S31 to S41 in the image recording process shown in Fig. 7. When the control unit 60 executes S31, the carriage 41 is located at the standby position, and the cap 81 is located at the covering position. The nozzle surface 43 of the head 42 is covered by the nozzle cap 82.

[0061] The control unit 60 receives an image recording instruction from an operation unit (not shown) (S31). Specifically, the control unit 60 waits in S31 until it receives an image recording instruction. When the control unit 60 receives the image recording instruction in S31, it closes the four valves 52b, 52c, 52m, and 52y (S32). Next, the control unit 60 moves the cap 81 downward from the covering position to the separated position (S33).

[0062] Next, the control unit 60 moves the carriage 41 leftward to the recording start position (S34). The recording start position is a predetermined position where the carriage 41 faces the platen 25. Next, the control unit 60 transports the sheet S to the recording start position (S35). Note that the control unit 60 may execute S35 in parallel with S32 to S34. When the control unit 60 completes the processes up to S35, the printer 10 is ready to start image recording.

[0063] Next, the control unit 60 executes a predetermined amount of image recording on the sheet S (S36). Specifically, the control unit 60 moves the carriage 41 in the left-right direction 9. While the carriage 41 is moving in the left-right direction 9, the control unit 60 ejects ink according to image data from the nozzles 44 of the head 42. S36 is an example of a recording operation.

[0064] Next, the control unit 60 judges whether image data remains (S37). If the control unit 60 judges in S37 that image data remains (S37: Yes), the control unit 60 proceeds to S38. In this case, the control unit 60 conveys the sheet S by a predetermined amount (S38) and proceeds to S36.

[0065] If the control unit 60 determines in S37 that no image data remains (S37: No), the control unit 60 proceeds to S39. In this case, the control unit 60 discharges the sheet S to a predetermined position (S39). Next, the control unit 60 moves the carriage 41 to the right to the standby position (S40). Next, the control unit 60 moves the cap 81 upward from the separated position to the covered position (S41). Thereafter, the control unit 60 proceeds to S31 to execute the next image recording.

[0066] [Initial installation process] When the printer 10 is shipped from the factory, there is no ink in the ink flow paths 56 and 57. Therefore, after the printer 10 is installed and the cartridges 51b, 51c, 51m, and 51c are attached to the cartridge holder 26, the control unit 60 executes the initial introduction process shown in FIG. 8. The initial introduction process is a process for introducing the four colors of ink from the cartridges 51b, 51c, 51m, and 51c to the head 42. When the control unit 60 executes S51, the carriage 41 is in the standby position and the cap 81 is in the covering position. The valves 52b, 52c, 52m, and 52y are closed, and the subtanks 53b, 53c, 53m, and 53y are empty.

[0067] After the cartridges 51b, 51c, 51m, and 51y are mounted in the cartridge holder 26, the control unit 60 receives an initial introduction instruction from the operation unit (S51). Specifically, the control unit 60 waits in S51 until it receives an initial introduction process. Next, the control unit 60 stops the automatic ink supply process (S52). While executing S53 to S60, the control unit 60 does not execute the automatic ink supply process shown in FIG. 6. Next, the control unit 60 initializes a count value N for counting the number of suctions to 1 (S53).

[0068] Next, the control unit 60 opens the four valves 52b, 52c, 52m, and 52y (S54). After this, black ink is supplied from the cartridge 51b to the subtank 53b, cyan ink is supplied from the cartridge 51c to the subtank 53c, magenta ink is supplied from the cartridge 51m to the subtank 53m, and yellow ink is supplied from the cartridge 51y to the subtank 53y. These inks are supplied using a water head difference.

[0069] Next, the control unit 60 waits until the ink amounts in all of the four sub-tanks 53b, 53c, 53m, and 53y become equal to or greater than the threshold value TH1 (S55). Specifically, the control unit 60 waits in S55 until it receives the sensor signals Sb1, Sc1, Sm1, and Sy1 from the sensors 54b, 54c, 54m, and 54y, respectively.

[0070] Next, the control unit 60 closes the four valves 52b, 52c, 52m, and 52y (S56). After this, the supply of black ink from the cartridge 51b to the subtank 53b, the supply of cyan ink from the cartridge 51c to the subtank 53c, the supply of magenta ink from the cartridge 51m to the subtank 53m, and the supply of yellow ink from the cartridge 51y to the subtank 53y are stopped.

[0071] Next, the control unit 60 drives the pump 85 for a predetermined time to perform suction (S57). While the control unit 60 is executing S57, the valves 52b, 52c, 52m, and 52y are closed. The lifting member 106 (see FIG. 5) is located at the abutting position, and the switching unit 84 (see FIG. 4) connects the pump 85 to the internal space of the exhaust cap 83. As a result, suction pressure is applied to the ink flow paths 57b, 57c, 57m, and 57y from the head 42 side, and the ink stored in the sub-tanks 53b, 53c, 53m, and 53c is introduced into the ink flow paths 57b, 57c, 57m, and 57y, respectively.

[0072] The pump 85 is driven for a predetermined time to suck up a predetermined amount of ink. The predetermined amount is larger than the capacity of the subtanks 53b, 53c, 53m, and 53y, and smaller than the volume of the ink flow paths 57b, 57c, 57m, and 57y. In particular, the longer the moving distance of the carriage 41 in the left-right direction 9 (in other words, the longer the width of the sheet S), the longer the length of the ink flow paths 57b, 57c, 57m, and 57y. Therefore, the predetermined amount sucked up by the pump 85 becomes sufficiently smaller than the volume of the ink flow paths 57b, 57c, 57m, and 57y. For this reason, when the control unit 60 executes S57 only once, the ink of each color introduced into the ink flow paths 57b, 57c, 57m, and 57y does not reach the head 42. Therefore, the control unit 60 repeatedly executes S54 to S57 a predetermined number of suction times (hereinafter, referred to as M) as shown below.

[0073] Next, the control unit 60 judges whether the count value N is equal to or greater than a predetermined number of suctions M (S58). If the control unit 60 judges in S58 that the count value N is less than the number of suctions M (S58: Yes), the control unit 60 proceeds to S59. In this case, the control unit 60 adds 1 to the count value N (S59) and proceeds to S54 to execute S54 to 57 again.

[0074] If the control unit 60 determines in S58 that the count value N is equal to or greater than the number of suctions M (S58: Yes), the control unit 60 proceeds to S60. In this case, the control unit 60 opens the four valves 52b, 52c, 52m, and 52y (S60). Next, the control unit 60 resumes the automatic ink supply that was stopped in S52 (S61), and ends the initial introduction process.

[0075] The number of suctions M in S58 is determined so as to satisfy, for example, the following expressions (1) and (2). M>Q / v ···(1) β×(m-1)×V <v<α×m×V ···(2) In formulas (1) and (2), Q is the suction volume required at the time of initial introduction, v is the suction volume when pump 85 is driven once in S57 (total suction volume in all ink flow paths), m is the number of ink flow paths in ink supply unit 50, V is the capacity of any one of sub-tanks 53b, 53c, 53m, and 53y, and α and β are safety factors. The safety factors α and β take values ​​greater than 0 and less than 1.

[0076] When the control unit 60 executes S54 to S56 for the first time, ink flows from the cartridges 51b, 51c, 51m, and 51y to the sub-tanks 53b, 53c, 53m, and 53y in an amount corresponding to the threshold value TH1. When the control unit 60 executes S57 for the first time next time, the amount of ink introduced from the sub-tanks 53b, 53c, 53m, and 53y to the ink flow paths 57b, 57c, 57m, and 57y differs depending on the flow path resistance of the ink flow paths 57b, 57c, 57m, and 57y, etc. When the control unit 60 executes S54 to S56 for the second or subsequent time, ink flows from the cartridges 51b, 51c, 51m, 51y to the sub-tanks 53b, 53c, 53m, 53y in an amount equivalent to the amount of ink that was introduced from the sub-tanks 53b, 53c, 53m, 53y to the ink flow paths 57b, 57c, 57m, 57y when the control unit 60 executed S57 the previous time.

[0077] In the initial introduction process, the control unit 60 supplies each subtank 53 with an amount of ink equal to or greater than the threshold value TH1, and then drives the pump 85 in a state where the supply of ink from each cartridge 51 to each subtank 53 is stopped. Therefore, when there is a resistance difference between the ink flow paths 57b, 57c, 57m, and 57y and there is a difference in the suction amount between the ink flow paths 57b, 57c, 57m, and 57y, after the subtank 53 connected to the ink path 57 with the smaller flow path resistance becomes empty, the suction pressure of the pump 85 is applied to the other ink flow paths 57. Therefore, the difference in the amount of ink flowing to the head 42 through the multiple ink flow paths 57b, 57c, 57m, and 57y by suction becomes smaller.

[0078] In the above embodiment, two different colors are selected from black, cyan, magenta, and yellow, and the first letters of the English spelling of the selected two colors are p and q (p and q are either b, c, m, or m). The cartridge 51p is an example of a first storage section, and the cartridge 51q is an example of a second storage section. The valve 52p is an example of a first valve, and the valve 52q is an example of a second valve. The sub-tank 53p is an example of a first tank, and the sub-tank 53q is an example of a second tank. The sensor 54p is an example of a first sensor, and the sensor 54q is an example of a second sensor. The sensor 55p is an example of a third sensor, and the sensor 55q is an example of a fourth sensor. The threshold value TH1 related to the sensor 54p is an example of a first threshold value, and the threshold value TH1 related to the sensor 54q is an example of a second threshold value. The threshold value TH2 related to the sensor 55p is an example of a third threshold value, and the threshold value TH2 related to the sensor 55q is an example of a fourth threshold value. Ink flow path 56p is an example of a flow path connecting the first storage portion and the first tank, and ink flow path 56q is an example of a flow path connecting the second storage portion and the second tank. Ink flow path 57p is an example of a first flow path, and ink flow path 57q is an example of a second flow path.

[0079] 6, the control unit 60 opens the valve 52p in response to receiving the sensor signal Sp2 from the sensor 55p, and closes the valve 52p in response to receiving the sensor signal Sp1 from the sensor 54p after receiving the sensor signal Sp2. This operation is an example of a first valve opening / closing operation. The control unit 60 opens the valve 52q in response to receiving the sensor signal Sq2 from the sensor 55q, and closes the valve 52q in response to receiving the sensor signal Sq1 from the sensor 54q after receiving the sensor signal Sq2. This operation is an example of a second valve opening / closing operation.

[0080] 8, the initial introduction instruction is an example of a suction instruction, S54 is an example of a valve opening operation, S56 is an example of a valve closing operation, and S57 is an example of a suction operation. In response to receiving the initial introduction instruction in S51, the control unit 60 executes a valve opening operation to close the valve 52 in S54. After executing the valve opening operation, the control unit 60 executes a valve closing operation to close the valve 52 in response to receiving a sensor signal from the sensor 54 indicating that the amount of ink in the subtank 53 is equal to or greater than the threshold value TH1. After executing the valve closing operation, the control unit 60 executes a suction operation to drive the pump 85 for a predetermined time.

[0081] [Effects of the embodiment] According to the printer 10 and ink supply unit 50 of the above embodiment, when suction is performed to introduce ink into multiple ink flow paths 56, 57 connecting multiple cartridges 51 and the head 42, by supplying a predetermined amount of ink to each subtank 53 and then driving the pump 85 while stopping the supply of ink from each cartridge 51 to each subtank 53, the difference in the amount of ink flowing to the head 42 through the multiple ink flow paths 57b, 57c, 57m, 57y by suction is reduced.

[0082] The control unit 60 executes a valve opening operation after executing the suction operation. Therefore, after executing the suction operation, ink is supplied to each subtank 53. The control unit 60 opens the corresponding valve 52 in response to receiving a sensor signal from the sensor 55 indicating that the amount of ink in the subtank 53 is less than the threshold value TH2. Therefore, when the amount of ink in each subtank 53 falls below a predetermined amount, ink is supplied to each subtank 53.

[0083] In response to receiving the initial introduction instruction, the control unit 60 repeatedly executes the valve opening operation, the valve closing operation, and the suction operation a predetermined number of suction times M (an example of a predetermined number of times). Therefore, the necessary amount of ink can be introduced into each ink flow path 57. After repeatedly executing the valve opening operation, the valve closing operation, and the suction operation a predetermined number of suction times M, the control unit 60 executes the valve opening operation. Therefore, after repeatedly executing the valve opening operation, the valve closing operation, and the suction operation, ink is supplied to each subtank 53.

[0084] The control unit 60 executes the image recording operation with the valve 52 closed. The control unit 60 executes the first valve opening / closing operation and the second valve opening / closing operation, and in response to receiving an initial introduction instruction, does not execute the first valve opening / closing operation and the second valve opening / closing operation until the suction operation is completed. Therefore, even if ink is automatically supplied from each cartridge 51 to each subtank 53, the automatic ink supply is stopped and each valve 52 is closed until the suction operation is completed.

[0085] [Variations] Various modifications can be made to the printer 10 and the control unit 60 according to the above embodiment. In the above embodiment, the control unit 60 executes the initial installation process shown in Fig. 8. In a modification, the control unit 60 executes the initial installation process shown in Fig. 9.

[0086] The initial introduction process shown in Fig. 9 is obtained by adding S71 and S74 to the initial introduction process shown in Fig. 8 and replacing S54 and S56 with S72 and S73, respectively. The control unit 60 according to the modified example uses four flags Fb, Fc, Fm, and Fy corresponding to black, cyan, magenta, and yellow to execute the initial introduction process. The flags Fb, Fc, Fm, and Fy are cleared when the amount of ink introduced of each color is insufficient, and are set when the amount of ink introduced of each color is sufficient. The flags Fb, Fc, Fm, and Fy are stored in the RAM 63 (see Fig. 3).

[0087] After executing S51 and S52, the control unit 60 clears the four flags Fb, Fc, Fm, and Fy (S71). After executing S53 or S59, the control unit 60 opens the valves 52b, 52c, 52m, and 52y that correspond to the cleared flags (S72). If, for example, the flags Fb and Fy are cleared and the flags Fc and Fm are set in S72, the control unit 60 opens the valves 52b and 52y and keeps the valves 52c and 52m closed.

[0088] After executing S55, the control unit 60 closes the open valves among the valves 52b, 52c, 52m, and 52y (S73). After executing S57, the control unit 60 sets the flags Fb, Fc, Fm, and Fy for the colors for which the amount of ink introduced is sufficient (S74). In S74, the control unit 60 determines whether the amount of ink introduced for each color is sufficient based on the sensor signals Sb1, Sc1, Sm1, Sy1, Sb2, Sc2, Sm2, and Sy2 output from the sensors 54b, 54c, 54m, 54y, 55b, 55c, 55m, and 55y, respectively. For example, the control unit 60 sets the flag Fb in response to determining that the amount of black ink introduced has become sufficient by executing S57 immediately before.

[0089] The control unit 60 according to the modified example performs the valve opening operation, the valve closing operation, and the suction operation a certain number of times that is less than a predetermined suction count M, and then keeps the valve 52 closed during the valve opening operation. The certain number of times is an example of the first number of times. Therefore, according to this modified example, the supply of ink from the cartridge 51 to the subtank 53 can be stopped for the flow paths in which the introduction of ink has been completed, thereby preventing unnecessary ink from being discharged.

[0090] In the above embodiment, the printer 10 is provided with one head 42, but the printer 10 may be provided with two or more heads 42. In the above embodiment, the ink supply unit 50 of the printer 10 is provided with four ink flow paths, but the printer 10 may be provided with two, three, five or more ink flow paths. [Explanation of symbols]

[0091] 10 Printer (image recording device) 42 Head 50 Ink supply unit (ink supply device) 51 Cartridge (first storage section, second storage section) 52 Valve (first valve, second valve) 53 Sub-tank (1st tank, 2nd tank) 54 Sensor (first sensor, second sensor) 54 Sensor (3rd sensor, 4th sensor) 56 Ink flow path (flow path) 57 Ink flow path (first flow path, second flow path) 60...Controller 85 Pump (suction mechanism)

Claims

1. A first reservoir for storing liquid; a second reservoir for storing liquid; a first tank located at a position lower than the first storage portion and having flexibility; a second tank located at a position lower than the second storage portion and having flexibility; a first valve that opens and closes a flow path connecting the first storage section and the first tank; a second valve that opens and closes a flow path connecting the second storage section and the second tank; a head through which liquid can flow from the first tank through a first flow path and through which liquid can flow from the second tank through a second flow path; a suction mechanism that, when driven, applies a suction pressure from the head side to the first flow path and the second flow path; A first sensor; A second sensor; A controller, The above controller is executes a valve opening operation to open the first valve and the second valve in response to receiving a suction command; after executing the valve opening operation, execute a valve closing operation to close the first valve in response to receiving a first signal from the first sensor indicating that the amount of liquid in the first tank is equal to or greater than a first threshold, and to close the second valve in response to receiving a second signal from the second sensor indicating that the amount of liquid in the second tank is equal to or greater than a second threshold; The liquid supplying apparatus performs a suction operation by driving the suction mechanism for a predetermined period of time after performing the valve closing operation.

2. 2. The liquid supplying apparatus according to claim 1, wherein the controller executes the valve opening operation after executing the suction operation.

3. The device further includes a third sensor and a fourth sensor, The above controller is A liquid supply device as described in claim 1, wherein the first valve is opened in response to receiving a third signal from the third sensor indicating that the amount of liquid in the first tank is less than a third threshold, and the second valve is opened in response to receiving a fourth signal from the fourth sensor indicating that the amount of liquid in the second tank is less than a fourth threshold.

4. 4. The liquid supplying apparatus according to claim 2, wherein the controller, in response to receiving the suction command, repeatedly executes the valve opening operation, the valve closing operation, and the suction operation a predetermined number of times.

5. The liquid supplying device according to claim 4 , wherein the controller performs the valve opening operation, the valve closing operation, and the suction operation a first number of the predetermined number of times, and then keeps the first valve closed during the valve opening operation.

6. 6. The liquid supplying apparatus according to claim 4, wherein the controller executes the valve opening operation after repeatedly executing the valve opening operation, the valve closing operation, and the suction operation the predetermined number of times.

7. The suction mechanism is driven for the predetermined time to suck in a predetermined amount of liquid, 7. The liquid supply apparatus according to claim 1, wherein the predetermined amount is greater than a capacity of the first tank and a capacity of the second tank.

8. The device further includes a third sensor and a fourth sensor, The above controller is performing a recording operation of discharging liquid from the head while the first valve and the second valve are closed; execute a first valve opening / closing operation to open the first valve in response to receiving a third signal from the third sensor indicating that the amount of liquid in the first tank is less than a third threshold value, and to close the first valve in response to receiving the first signal from the first sensor after receiving the third signal; execute a second valve opening / closing operation to open the second valve in response to receiving a fourth signal from the fourth sensor indicating that the amount of liquid in the second tank is less than a fourth threshold value, and to close the second valve in response to receiving the second signal from the second sensor after receiving the fourth signal; 8. The liquid supplying apparatus according to claim 1, wherein, in response to receiving the suction command, the first valve opening / closing operation and the second valve opening / closing operation are not executed until the suction operation is completed.

9. A liquid supply device according to any one of claims 1 to 8; a transport section for transporting a recording medium onto which the liquid ejected from the head lands.

10. A liquid supplying method using a first reservoir for storing liquid, a second reservoir for storing liquid, a first tank located at a lower position than the first reservoir and having flexibility, a second tank located at a lower position than the second reservoir and having flexibility, and a head through which liquid can flow from the first tank through a first flow path, and through which liquid can flow from the second tank through a second flow path, a valve opening step of opening a first valve that opens and closes a flow path connecting the first storage portion and the first tank and a second valve that opens and closes a flow path connecting the second storage portion and the second tank in response to receiving a suction command; a valve closing step of closing the first valve in response to receiving a first signal from a first sensor indicating that the amount of liquid in the first tank is equal to or greater than a first threshold, and closing the second valve in response to receiving a second signal from a second sensor indicating that the amount of liquid in the second tank is equal to or greater than a second threshold, after the valve opening step; a suction step of driving a suction mechanism for a predetermined period of time after the valve closing step, the suction mechanism being driven to apply suction pressure from the head side to the first flow path and the second flow path.

Images