Liquid ejection apparatus and cleaning method

Abstract

To suppress consumption of ink during cleaning of a head.SOLUTION: A liquid discharge apparatus according to the present disclosure includes a head having a nozzle surface on which a plurality of nozzle rows are arranged, a supply unit that supplies a liquid to the nozzle row and adjusts a pressure of the liquid in the nozzle row, a wiper unit that wipes the nozzle surface with a wiper, and a controller. The controller performs a pressurization process of pressurizing the liquid of a specific nozzle row among the plurality of nozzle rows to discharge the liquid from the specific nozzle row, a wiping process of wiping the nozzle surface with the wiper after the pressurization process, and a flushing process of discharging the liquid from the plurality of nozzle rows after the wiping process.SELECTED DRAWING: Figure 6

Description

[Technical Field]

[0001] The present invention relates to a liquid ejection apparatus and a cleaning method. [Background technology]

[0002] Patent Document 1 describes that when cleaning the head, the ink inside the head is pressurized to expel the ink from the nozzles, and then wiping (the operation of wiping the nozzle surface with a wiper) is performed. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2020-199658 Summary of the Invention [Problem to be solved by the invention]

[0004] When a wiping process is performed after a pressurization process in which the ink (liquid) in the head is pressurized and expelled from the nozzles, the ink in the nozzles becomes mixed with other colors of ink, resulting in color mixing. For this reason, a flushing process (a process in which liquid is ejected from the nozzles) is performed after the wiping process to expel the mixed ink from the nozzles. In this way, liquid is consumed by the pressurization process and flushing process during cleaning.

[0005] SUMMARY OF THE INVENTION An object of the present invention is to reduce the consumption of liquid when cleaning the head. [Means for solving the problem]

[0006] The main invention to achieve the above object is: a head having a nozzle surface on which a plurality of nozzle rows are arranged; a supply unit that supplies liquid to the nozzle row and adjusts the pressure of the liquid in the nozzle row; a wiper unit that wipes the nozzle surface with a wiper; A controller and Equipped with The controller a pressurization process in which the liquid in a specific nozzle row among the plurality of nozzle rows is pressurized to cause the liquid to be discharged from the specific nozzle row; a wiping process of wiping the nozzle surface with the wiper after the pressurizing process; a flushing process in which the liquid is ejected from the plurality of nozzle rows after the wiping process; The liquid ejection device is characterized by performing the above.

[0007] Other features of the present invention will become apparent from the description of this specification. [Effects of the Invention]

[0008] According to the present invention, it is possible to reduce the consumption of ink when cleaning the head. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is a schematic explanatory diagram of a liquid ejection device 1. As shown in FIG. [Figure 2] FIG. 2 is a block diagram of the liquid ejection device 1. As shown in FIG. [Figure 3] FIG. 3 is an explanatory diagram of the head 20. [Figure 4] FIG. 4 is an explanatory diagram of the supply unit 30 and the cap unit 50. As shown in FIG. [Figure 5] FIG. 5 is a flow diagram of the cleaning process. [Figure 6] 6A to 6D are explanatory diagrams of the cleaning process of this embodiment. [Figure 7] 7A to 7D are explanatory diagrams of the cleaning process of the comparative example. DETAILED DESCRIPTION OF THE INVENTION

[0010] === Implementation form === <Basic configuration> Fig. 1 is a schematic explanatory diagram of a liquid ejection device 1. Fig. 2 is a block diagram of the liquid ejection device 1.

[0011] The liquid ejection device 1 is a device that ejects liquid onto a medium M (printing paper, printing film, etc.). Here, the liquid ejection device 1 is a device (inkjet printer) that prints an image onto the medium M. However, the liquid ejection device 1 does not have to be a device that prints an image onto the medium M, as long as it is a device that ejects liquid from the head 20. In other words, the liquid ejected from the head 20 is not limited to ink. The liquid ejection device 1 has a moving unit 10 (carriage unit 11 and transport unit 12), the head 20, a supply unit 30, a cleaning unit 40 (cap unit 50 and wiper unit 60), and a controller 70.

[0012] The moving unit 10 is a unit that moves at least one of the medium M and the head 20. Here, the moving unit 10 has a carriage unit 11 and a transport unit 12. The carriage unit 11 is a unit that moves a carriage 111 carrying the head 20 in the scanning direction. The transport unit 12 is a unit that transports the medium M in the transport direction. Note that the moving unit 10 is not limited to having the carriage unit 11 and the transport unit 12. For example, the moving unit 10 may be configured with a carriage unit 11 that moves the carriage 111 in two dimensions relative to the fixed medium M. The moving unit 10 may also be configured with a transport unit 12 that transports the medium M relative to the fixed head 20.

[0013] FIG. 3 is an explanatory diagram of the head 20. The head 20 has a plurality of nozzles 211 that eject liquid. The head 20 in the figure has four nozzle rows 21. Here, the nozzle rows 21 are provided to eject liquids of different colors (inks in this case), including color ink nozzle rows (cyan ink nozzle row, magenta ink nozzle row, and yellow ink nozzle row) that eject color inks (cyan ink, magenta ink, and yellow ink), and a white ink nozzle row that ejects white ink. The number of nozzle rows 21 is not limited to four and may be any other number. For example, the head 20 may further include a black ink nozzle row. Also, multiple nozzle rows 21 that eject ink of the same color may be provided. For example, two or more white ink nozzle rows may be provided. Each nozzle row 21 has a plurality of nozzles 211 lined up in the transport direction. The nozzles 211 open in a nozzle surface 22 (the bottom surface of the head 20) of the head 20, and liquid is ejected from these openings.

[0014] Each nozzle 211 is provided with a discharge drive unit (not shown). For example, the discharge drive unit is configured with a piezoelectric element. When the discharge drive unit is driven, droplets are discharged from the nozzle 211. Note that the discharge drive unit is not limited to a piezoelectric element, and may be configured with, for example, a heater.

[0015] FIG. 4 is an explanatory diagram of the supply unit 30 and the cap unit 50. As shown in FIG. The supply unit 30 is a unit for supplying liquid to the head 20. The supply unit 30 has a tank 31, a supply path 32, a liquid supply pump 33, a damper 34, and a pressure sensor 35. The tank 31 is a liquid supply source and is formed, for example, by an ink cartridge. The supply path 32 is a liquid flow path between the tank 31 and the head 20 and is formed, for example, by a tube. The liquid supply pump 33 is a pump for sending liquid from the tank 31 to the head 20. The liquid supply pump 33 also has the function of adjusting the pressure of the liquid in the head 20. When the liquid supply pump 33 is driven in the forward direction, the liquid in the head 20 is pressurized. When the liquid supply pump 33 is driven in the reverse direction, the liquid in the head 20 is depressurized. The damper 34 is a component that reduces pressure fluctuations of the liquid in the head 20. The damper 34 is sometimes called a sub-tank. The pressure of the liquid in the damper 34 is sometimes called the pressure of the liquid in the head 20. The pressure sensor 35 measures the pressure of the liquid inside the damper 34 (the pressure of the liquid inside the head 20). The pressure sensor 35 outputs the measurement result to the controller 70. The controller 70 controls the liquid feed pump 33 based on the measurement result of the pressure sensor 35. For example, when ejecting droplets from the head 20, the drive of the liquid feed pump 33 is controlled based on the detection result of the pressure sensor 35 so that the pressure of the liquid inside the head 20 is slightly lower than atmospheric pressure so that the surface of the liquid on the nozzle surface 22 (ink meniscus) becomes concave. A supply unit 30 is provided for each nozzle row 21.

[0016] The cleaning unit 40 is a unit for cleaning the head 20. The cleaning unit 40 has a cap unit 50 and a wiper unit 60 (see FIG. 2).

[0017] The cap unit 50 is a unit for covering the nozzle surface 22 of the head 20 with a cap 51. The cap unit 50 is used for cleaning processing as described below, but is also used to prevent the liquid inside the nozzles 211 from drying out by covering the nozzle surface 22 with the cap 51 when the liquid ejection device 1 is stopped. The cap unit 50 has a cap 51, an absorber 52, a lifting mechanism 53, and a suction pump 54 (see FIG. 4). The cap 51 is a member that covers the nozzle surface 22 of the head 20.

[0018] The cap 51 is formed in a concave shape. In other words, the cap 51 is formed in a box shape with an open top. The cap 51 has a bottom and a wall rising from the periphery of the bottom, and the bottom and the wall form a storage section (storage space). The absorber 52 is stored in the storage section of the cap 51.

[0019] The absorber 52 is a member that absorbs liquid. The absorber 52 is housed in the cap 51. The upper surface of the absorber 52 is located slightly below the upper edge (upper edge of the wall portion) of the cap 51. As a result, when the upper edge of the cap 51 comes into contact with the nozzle surface 22 of the head 20, a predetermined gap is formed between the absorber 52 and the nozzle surface 22. As will be described later, by bringing the liquid adhering to the nozzle surface 22 into contact with the absorber 52, the liquid on the nozzle surface 22 can be absorbed by the absorber 52.

[0020] The lifting mechanism 53 is a mechanism that changes the distance between the nozzle surface 22 of the head 20 and the cap 51. Here, the lifting mechanism 53 is configured to be able to lift and lower the cap 51 (to be able to move in the vertical direction). However, it is sufficient that the lifting mechanism 53 is configured to be able to lift and lower at least one of the head 20 and the cap 51. The lifting mechanism 53 moves the head 20 and the cap 51 closer to or farther apart in the vertical direction.

[0021] The suction pump 54 is a pump for sucking the liquid and air inside the cap 51. When the suction pump 54 is driven, the liquid inside the cap 51 (the liquid absorbed by the absorber 52) is sucked out. The liquid sucked out of the cap 51 by the suction pump 54 is discharged into a waste liquid tank (not shown).

[0022] The wiper unit 60 is a unit for wiping the nozzle surface 22 of the head 20. As shown in FIG. 1, the wiper unit 60 is provided near the cap unit 50. The wiper unit 60 has a wiper 61 (see FIG. 6C) and an elevation mechanism (not shown). The wiper 61 is a member that wipes the nozzle surface 22 of the head 20. For example, the wiper 61 is made of a plate-shaped elastic member. When the elevation mechanism raises the wiper 61, the upper edge of the wiper 61 comes into contact with the nozzle surface 22. By moving the carriage 111 (head 20) in the scanning direction while the wiper 61 is in contact with the nozzle surface 22, the wiper 61 can wipe the nozzle surface 22. Note that the wiper unit 60 may be configured so that the wiper 61 moves in the scanning direction to wipe the nozzle surface 22.

[0023] The controller 70 is a control unit that controls the liquid ejection device 1. The controller 70 controls each unit of the liquid ejection device 1 (movement unit 10, head 20, supply unit 30, cleaning unit 40). The controller 70 has an arithmetic processing unit and a storage device, not shown. The arithmetic processing unit is composed of, for example, a CPU, an MPU, etc. The storage device has RAM used to execute programs, ROM for storing programs, etc. The arithmetic processing unit executes the programs stored in the storage device, thereby performing various processes (printing process, cleaning process, etc.). Figure 2 shows functional blocks of the controller 70. The controller 70 has a print processing unit 71 and a cleaning processing unit 72.

[0024] The print processing unit 71 performs processing (print processing) for printing on the medium M. For example, the print processing alternately repeats a liquid ejection operation in which the carriage unit 11 is driven to move the head 20 in the scanning direction while ejecting liquid from the head 20, and a transport operation in which the transport unit 12 is driven to transport the medium M in the transport direction, thereby printing an image on the medium M.

[0025] The cleaning processing unit 72 performs a process (cleaning process) for cleaning the head 20. The cleaning processing unit 72 has a pressure processing unit 72A, a pressure reduction processing unit 72B, a wiping processing unit 72C, and a flushing processing unit 72D. Each processing unit (pressure processing unit 72A, pressure reduction processing unit 72B, wiping processing unit 72C, and flushing processing unit 72D) is realized by the arithmetic processing unit that constitutes the controller 70 executing a program stored in a storage device. The process performed by each processing unit will be described below.

[0026] <Cleaning process> Fig. 5 is a flow diagram of the cleaning process. Figs. 6A to 6D are explanatory diagrams of the cleaning process of this embodiment. Figs. 7A to 7D are explanatory diagrams of the cleaning process of a comparative example. In both the cleaning process of this embodiment and the cleaning process of the comparative example, the controller 70 sequentially performs a pressurization process (S001), a depressurization process (S002), a wiping process (S003), and a flushing process (S004) as the cleaning process. First, the points common to this embodiment and the comparative example will be described.

[0027] First, the controller 70 (pressurizing unit 72A) performs a pressurizing process (S001; see FIGS. 6A and 7A). The pressurizing process is a process of pressurizing the liquid in the head 20 to cause the liquid to be ejected from the nozzles 211. At this time, the controller 70 moves the carriage 111 so that the nozzle surface 22 of the head 20 faces the absorber 52 of the cap unit 50. After the nozzle surface 22 of the head 20 faces the absorber 52 of the cap unit 50, the controller 70 drives the liquid supply pump 33 in the forward direction to pressurize the liquid in the head 20, thereby increasing the pressure of the liquid in the head 20 to a pressure higher than atmospheric pressure. Specifically, the controller 70 controls the liquid supply pump 33 based on the detection result of the pressure sensor 35 so that the pressure of the liquid in the head 20 is several kPa (e.g., 3.0 kPa to 4.0 kPa) higher than atmospheric pressure. The pressure of the liquid in the head 20 during the pressurizing process is sometimes referred to as the "first pressure."

[0028] If the pressure of the liquid inside the head 20 is about 100 kPa higher than atmospheric pressure, the liquid will spurt out forcefully from the nozzle 211. In contrast, if the pressure of the liquid inside the head 20 (first pressure) is about several kPa higher than atmospheric pressure, as in the case of pressurization processing, the pressure difference is relatively small, so the liquid will ooze out from the nozzle 211 (it will not spurt out).

[0029] When the liquid seeps out from the nozzles 211 due to the pressurization process, the liquid drips from the nozzle surface 22 (the liquid drips from the nozzle surface 22) as shown in FIGS. 6A and 7A. The pressurization process is performed with the nozzle surface 22 facing the absorber 52 of the cap unit 50, so the liquid drips from the nozzle surface 22 onto the absorber 52. During the pressurization process, the controller 70 drives the suction pump 54 to discharge the liquid that has dripped into the cap 51.

[0030] Next, the controller 70 (decompression processing unit 72B) performs a decompression process (S002; see FIGS. 6B and 7B). The decompression process is a process of reducing the pressure of the liquid in the head 20. The controller 70 controls the liquid feed pump 33 to reduce the pressure of the liquid in the head 20 to a pressure lower than the first pressure during the pressurization process. Note that in order to eject droplets from the head 20 in the flushing process (S004) described below, the surface of the liquid (ink meniscus) on the nozzle surface 22 needs to be concave. Therefore, during the decompression process, the controller 70 drives the liquid feed pump 33 based on the detection result of the pressure sensor 35 so that the pressure of the liquid in the head 20 (second pressure) is slightly lower than atmospheric pressure. The pressure of the liquid in the head 20 during the decompression process is sometimes referred to as the "second pressure."

[0031] When the pressure of the liquid inside the head 20 drops from the first pressure to the second pressure due to the decompression process, the liquid stops flowing out of the nozzles 211. As shown in FIGS. 6B and 7B, the liquid remains attached to the nozzle surface 22 during the decompression process. Even during the decompression process, the liquid may wet and spread on the nozzle surface 22, causing the liquid to drip. For this reason, the decompression process, like the pressurization process, is performed with the nozzle surface 22 facing the absorber 52 of the cap unit 50, and any liquid dripping from the nozzle surface 22 falls onto the absorber 52. The controller 70 also drives the suction pump 54 during the decompression process to discharge any liquid that has dripped into the cap 51.

[0032] Next, the controller 70 (wiping processing unit 72C) performs a wiping process (S003; see FIGS. 6C and 7C). The wiping process is a process in which the wiper 61 wipes the nozzle surface 22. The controller 70 moves the carriage 111 to move the head 20 to the position of the wiper unit 60, and controls the lifting mechanism of the wiper unit 60 to raise the wiper 61. Then, as shown in FIGS. 6C and 7C, the controller 70 moves the carriage 111 in the scanning direction while bringing the wiper 61 into contact with the nozzle surface 22, causing the wiper 61 to wipe the nozzle surface 22. It should be noted that, after moving the head 20 to the position of the wiper unit 60 and raising the wiper 61 to bring the wiper 61 into contact with the nozzle surface 22, instead of moving the carriage 111 to move the head 20 relative to the wiper 61, the wiper 61 may be moved relative to the head 20 to wipe the nozzle surface 22. In this way, after bringing the wiper 61 into contact with the nozzle surface 22, at least one of the head 20 and the wiper 61 is moved to move the head 20 and the wiper 61 relatively, thereby allowing the wiper 61 to wipe the nozzle surface 22.

[0033] However, if the wiping process is performed when the nozzle surface 22 is dry, there is a risk of damaging the nozzle surface 22. In contrast, by performing the wiping process after the pressurization process, the process is performed with liquid adhering to the nozzle surface 22, as shown in Figures 6C and 7C, and damage to the nozzle surface 22 can be suppressed. In other words, the above-mentioned pressurization process is performed in order to perform a wet wiping process. Furthermore, if the wiping process is performed immediately after the pressurization process, there is a risk that liquid will drip and contaminate the inside of the device while the head 20 is moving to the position of the wiper unit 60, so the above-mentioned depressurization process is performed after the pressurization process and before the wiping process.

[0034] Finally, the controller 70 (flushing processing unit 72D) performs a flushing process (S004; see FIGS. 6D and 7D). The flushing process is a process of discharging liquid from the nozzles 211 by discharging droplets from the nozzles 211. At this time, the controller 70 moves the carriage 111 so that the nozzle surface 22 (nozzles 211) of the head 20 faces the absorber 52 of the cap unit 50. Then, as shown in FIGS. 6D and 7D, the controller 70 drives the discharge drive unit (not shown; for example, a piezoelectric element) of each nozzle 211 to discharge droplets from the nozzle 211. During the flushing process, the controller 70 drives the suction pump 54 to discharge the liquid discharged into the cap 51 (and the absorber 52).

[0035] Next, the differences between the cleaning process of this embodiment (FIGS. 6A to 6D) and the cleaning process of the comparative example (FIGS. 7A to 7D) will be described.

[0036] In the comparative example, during the pressurization process of S001, the controller 70 pressurizes the liquid in all nozzle rows 21 of the head 20, causing the liquid to be ejected from the nozzles 211 (see FIG. 7A). As a result, in the comparative example, a mixture of multiple color liquids spreads across the nozzle surface 22 of the head 20. Furthermore, in the comparative example, the controller 70 performs the pressurization process on all nozzle rows, and therefore the depressurization process on all nozzle rows. When the depressurization process is performed on a nozzle that has been pressurized, the liquid on the nozzle surface flows back into that nozzle, making it easier for the liquid to mix colors in all nozzle rows in the comparative example. For this reason, in the comparative example, during the flushing process of S004, a relatively large amount of liquid needs to be ejected to expel the mixed color liquid.

[0037] In contrast, in this embodiment, during the pressurization process of S001, the controller 70 (pressurization processing unit 72A) pressurizes the liquid in a specific nozzle row 21, causing the liquid to be ejected from the nozzles 211 (see FIG. 6A). In the following description, the specific nozzle row 21 that ejects the liquid during the pressurization process may be referred to as the "pressurization target nozzle row." Here, the pressurization target nozzle row is the nozzle row located at the left end of the head in FIG. 6A, and is the white ink nozzle row 21(W) shown in FIG. 3. In this embodiment, during the pressurization process of S001, the controller 70 does not pressurize the liquid in the nozzle rows 21 other than the pressurization target nozzle row (nozzle rows other than the specific nozzle row; the cyan ink nozzle row 21(C), magenta ink nozzle row 21(M), and yellow ink nozzle row 21(Y) shown in FIG. 3), and the liquid is not ejected from the nozzles 211 of the other nozzle rows 21 (see FIG. 6A). For this reason, in this embodiment, only the liquid of a specific color (single color; white in this case) spreads onto the nozzle surface 22 of the head 20 in the vicinity of the nozzle row to be pressurized. In other words, in this embodiment, the liquid that spreads onto the nozzle surface does not mix colors during the pressurization process. Furthermore, in this embodiment, the controller 70 (decompression processing unit 72B) performs the decompression processing of S002 only on the pressurized nozzle array (because the pressurization processing is not performed on nozzle arrays other than the pressurized nozzle array). For this reason, in this embodiment, the only nozzle array in which liquid on the nozzle surface flows back into the nozzles during the decompression processing of S002 is the pressurized nozzle array, and in nozzle arrays other than the pressurized nozzle array, liquid on the nozzle surface is less likely to flow back into the nozzles. Furthermore, in the pressurized nozzle array, even if liquid on the nozzle surface flows back into the nozzles, only liquid of the same color will enter the nozzles. In other words, in this embodiment, compared to the comparative example, color mixing of liquid in the nozzles of the nozzle array is less likely to occur during the decompression processing of S002. Therefore, in this embodiment, the amount of liquid ejected during the flushing process of S004 can be reduced compared to the comparative example. In other words, in this embodiment, the consumption of liquid during cleaning of the head 20 can be reduced compared to the comparative example.

[0038] Furthermore, in this embodiment, during the pressurization process of S001, the controller 70 (pressurization processing unit 72A) pressurizes the liquid in a nozzle row (pressurization target nozzle row) that is located at the end of the multiple nozzle rows 21 in the scanning direction, causing the liquid to be discharged from the nozzles 211 of this nozzle row (see FIG. 6A). That is, in this embodiment, the pressurization target nozzle row is located at the end of the scanning direction. Furthermore, in this embodiment, during the wiping process of S003, the controller 70 (wiping processing unit 72C) first brings the wiper 61 into contact with the pressurization target nozzle row, and then wipes the nozzle surface 22 with the wiper 61 (see FIG. 6C). Note that the pressurization target nozzle row (the specific nozzle row 21 that discharges liquid during the pressurization process) does not have to be located at the end. In this case, however, the operation of performing the wet wiping process on all nozzle rows becomes complicated. In contrast, in this embodiment, liquid is released from the nozzle row 21 at the end during the pressurization process, and in the wiping process, wet wiping of all nozzle rows can be achieved by the simple operation of wiping the nozzle surface 22 with the wiper 61 in order from the end.

[0039] White ink has larger pigments than other color inks (cyan ink, magenta ink, and yellow ink), and therefore has the property that the pigments tend to settle. Liquids with pigments that tend to settle or with large pigments are likely to cause nozzle clogging. Therefore, during the pressurization process in S001, the controller 70 (pressurization processing unit 72A) desirably ejects liquids that tend to settle or with large pigments from the nozzles 211. This prevents nozzle clogging. In the above description, the white ink nozzle row 21(W) is located at the end, and white ink is ejected from the nozzles 211 during the pressurization process. However, the liquid ejected from the nozzles during the pressurization process does not have to be white ink. Even if the liquid ejected from the pressurized nozzle row during the pressurization process is an ink that does not tend to settle, it is still possible to achieve the effect of reducing liquid consumption during cleaning of the head 20.

[0040] The controller 70 (pressurization processing unit 72A) may change the nozzle row to be pressurized. For example, the controller 70 may determine the nozzle row to be pressurized based on the remaining amount of liquid (the amount of liquid remaining in the tank 31). In this case, the controller 70 may determine the liquid with the largest remaining amount during the pressurization process and determine the nozzle row 21 corresponding to that liquid as the nozzle row to be pressurized. This results in the liquid with the largest remaining amount being consumed during the pressurization process, making it possible to equalize the remaining amount of liquid and prevent a specific liquid from being unevenly consumed. In this way, the nozzle row to be pressurized (the specific nozzle row 21 that outputs liquid during the pressurization process) does not have to be a predetermined nozzle row.

[0041] Furthermore, the number of nozzle rows to be pressurized does not have to be one. For example, if the head 20 has two white nozzle rows, during the pressurization process of S001, the controller 70 (pressurization processing unit 72A) may designate the two white nozzle rows as the pressurized nozzle rows, and pressurize the white ink in the two white nozzle rows to eject the white ink. In this way, as long as the same type of liquid (single color liquid) is ejected from the nozzles 211, there may be multiple nozzle rows to be pressurized.

[0042] In this embodiment, during the flushing in step S004, the amount of liquid ejected from the pressurized nozzle row is less than the amount of liquid ejected from the nozzle rows other than the pressurized nozzle row, thereby making it possible to reduce the consumption of liquid during cleaning of the head 20. Furthermore, in this embodiment, the controller (flushing processing unit 72D) does not eject liquid from the pressurized nozzle row during the flushing in S004 (see FIG. 6D). This makes it possible to further reduce the consumption of liquid during cleaning of the head 20. However, liquid may be ejected from the pressurized nozzle row during the flushing process in S004.

[0043] During the wiping process, there is a risk that the liquid from the pressurized nozzle array may seep into the nozzles 211 of other nozzle arrays 21 (nozzle arrays other than the pressurized nozzle array). Meanwhile, the amount of liquid that seeps into the nozzles 211 during the wiping process is considered to be greater for nozzle arrays 21 closer to the pressurized nozzle array and less for nozzle arrays 21 farther from the pressurized nozzle array. For this reason, during the flushing process of S004, the controller may reduce the amount of liquid ejected from nozzle arrays farther from the pressurized nozzle array. For example, if the white ink nozzle array 21(W) shown in FIG. 3 is the pressurized nozzle array, the controller (flushing processing unit 72D) may reduce the amount of liquid ejected from the yellow ink nozzle array 21(Y) compared to the amount of liquid ejected from the cyan ink nozzle array 21(C). This reduces the consumption of liquid during cleaning of the head 20. However, during the flushing process of S004, the same amount of liquid may be ejected from each nozzle array 21.

[0044] As described above, the liquid ejection device 1 of this embodiment includes a head 20 having a nozzle surface 22 on which a plurality of nozzle rows 21 are arranged, a supply unit 30 that adjusts the pressure of the liquid in the nozzle rows 21, a wiper unit 60 that wipes the nozzle surface 22 with a wiper 61, and a controller 70. In this embodiment, the controller 70 performs a pressurization process (S001, see FIG. 6A) in which the liquid in a pressurization target nozzle row (a specific nozzle row among the plurality of nozzle rows) is pressurized to eject the liquid from the pressurization target nozzle row, a wiping process (S003, see FIG. 6C) in which the nozzle surface 22 is wiped with the wiper 61 after the pressurization process, and a flushing process (S004, see FIG. 6D) in which the liquid is ejected from the plurality of nozzle rows 21 after the wiping process. This liquid ejection device 1 can reduce ink consumption during head cleaning.

[0045] ===Other embodiments=== The above-described embodiments are presented as examples and do not limit the scope of the invention. The above configurations can be implemented in appropriate combinations, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. The above-described embodiments and their modifications are included in the scope and spirit of the invention, as well as in the inventions described in the claims and their equivalents. [Explanation of symbols]

[0046] 1 liquid ejection device, 10 moving unit, 11 carriage unit, 111 carriage, 12 transport units, 20 heads, 21 nozzle row, 211 nozzle, 22 nozzle surface, 30 supply units, 31 tanks, 32 supply channel, 33 liquid transfer pump, 34 damper, 35 pressure sensor, 40 cleaning units, 50 cap units, 51 Cap, 52 Absorbent, 53 lifting mechanism, 54 suction pump, 60 wiper unit, 61 wiper, 70 controllers, 71 printing processing section, 72 cleaning processing section, 72A pressurized processing section, 72B reduced pressure processing section, 72C wiping processing section, 72D flushing processing section, M medium

Claims

1. a head having a nozzle surface on which a plurality of nozzle rows are arranged; a supply unit that supplies liquid to the nozzle row and adjusts the pressure of the liquid in the nozzle row; a wiper unit that wipes the nozzle surface with a wiper; A controller and Equipped with The controller a pressurization process in which the liquid in a specific nozzle row among the plurality of nozzle rows is pressurized to cause the liquid to be discharged from the specific nozzle row; a wiping process of wiping the nozzle surface with the wiper after the pressurizing process; a flushing process in which the liquid is ejected from the plurality of nozzle rows after the wiping process; A liquid ejection device characterized by performing the above.

2. The liquid ejection device according to claim 1 , The liquid ejection device is characterized in that the specific nozzle row is a nozzle row that is arranged at an end of the plurality of nozzle rows.

3. The liquid ejection device according to claim 2, The liquid ejection apparatus is characterized in that, during the wiping process, the controller wipes the nozzle surface with the wiper while first bringing the wiper into contact with the specific nozzle row.

4. The liquid ejection device according to claim 1 , A liquid ejection device, characterized in that the pigment in the liquid in the specific nozzle row is more likely to settle than in the liquid in nozzle rows other than the specific nozzle row.

5. The liquid ejection device according to any one of claims 1 to 4, The liquid ejection device is characterized in that, during the flushing process, the amount of liquid ejected from the specific nozzle row is smaller than the amount of liquid ejected from the nozzle rows other than the specific nozzle row.

6. The liquid ejection device according to claim 5, The liquid ejection device is characterized in that the controller does not eject the liquid from the specific nozzle row during the flushing process.

7. The liquid ejection device according to claim 5, The liquid ejection device is characterized in that, during the flushing process, the controller reduces the amount of liquid ejected from a nozzle row that is farther away from the specific nozzle row.

8. a head having a nozzle surface on which a plurality of nozzle rows are arranged; a supply unit that supplies liquid to the nozzle row and adjusts the pressure of the liquid in the nozzle row; a wiper unit that wipes the nozzle surface with a wiper; A method for cleaning a liquid ejection device, comprising: a pressurization process in which the liquid in a specific nozzle row among the plurality of nozzle rows is pressurized to cause the liquid to be discharged from the specific nozzle row; a wiping process of wiping the nozzle surface with the wiper after the pressurizing process; a flushing process in which the liquid is ejected from the plurality of nozzle rows after the wiping process; A cleaning method characterized by carrying out the steps of:

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