Liquid dispensing device

Abstract

To provide means that can reduce amounts of liquid that is consumed in maintenance processing.SOLUTION: In a printer 10, a plurality of nozzles 33 included in a head 32 form first-fourth nozzle rows K1-K4. A control part 60 determines whether a condition in which an ink residual amount sensor 41 is in an OFF state is satisfied or not (S14), and when determining that the condition is satisfied (S14:Yes), executes purge to some nozzle rows of the first-fourth nozzle rows K1-K4 (S39) and executes recording processing on a sheet while making nozzles in the some nozzle rows discharge ink to the sheet (S41 and S26).SELECTED DRAWING: Figure 7

Description

[[Technical Field]]

[0001] The present invention relates to a liquid ejection apparatus comprising a head including a plurality of nozzle rows. [[Background Art]]

[0002] A printer including a head having a plurality of nozzles that eject ink is known. Such a printer performs maintenance processing on the head in order to resolve ink ejection failure from the nozzles.

[0003] Patent Document 1 discloses a recording apparatus that records a mark on a back surface of a sheet. This recording apparatus includes a detection means that detects that no mark is recorded and outputs an ink non-ejection signal, and a determination means that determines whether a remaining amount of ink is equal to or greater than a predetermined amount. In this recording apparatus, when an ink non-ejection signal is output from the detection means and the determination means determines that the remaining amount of ink is equal to or greater than the predetermined amount, the recording apparatus determines that ink non-ejection has occurred and performs a head recovery operation; and when the determination means determines that the remaining amount of ink is less than the predetermined amount, the recording apparatus determines that ink is exhausted. [[Prior Art Literature]] [[Patent Literature]]

[0004] [[Patent Document 1]] Japanese Unexamined Patent Publication No. 2006-297869 [[Summary of the Invention]] [[Problem to be Solved by the Invention]]

[0005] When the head includes a plurality of nozzle rows, conventional printers perform maintenance processing on all of the plurality of nozzle rows included in the head. For this reason, in conventional printers, a large amount of ink is consumed in the maintenance processing, resulting in less ink available for printing.

[0006] This invention has been made in view of the above circumstances, and its purpose is to provide a means that can reduce the amount of liquid consumed in maintenance processes. [Means for solving the problem]

[0007] (1) The liquid dispensing device of the present invention comprises a container for holding liquid, a head including a plurality of nozzles for dispensing the liquid supplied from the container, and a control unit. The plurality of nozzles are arranged in a first direction to form a plurality of nozzle rows. The control unit performs a condition determination process to determine whether the condition that the remaining amount of liquid contained in the container is less than a predetermined amount is met, and if the condition determination process determines that the condition is met, it performs a maintenance process on some of the nozzle rows of the plurality of nozzle rows and causes liquid to be dispensed from the nozzles in the nozzle rows to the sheet.

[0008] According to the above liquid dispensing device, when the remaining amount of liquid is less than a predetermined amount, maintenance processing is performed on some of the nozzle rows, and liquid is dispensed from the nozzles in the nozzle rows after the maintenance processing. This reduces the amount of liquid consumed during maintenance processing, and allows liquid to be dispensed onto the sheet even when the remaining amount of liquid is low, after the maintenance processing has been performed.

[0009] (2) The liquid dispensing device of the present invention comprises a container for containing liquid, a head including a plurality of nozzles for dispensing the liquid supplied from the container, a waste liquid container for containing the waste liquid discharged from the head, and a control unit. The plurality of nozzles are arranged in a first direction to form a plurality of nozzle rows. The control unit performs a condition determination process to determine whether the amount of waste liquid contained in the waste liquid container is equal to or greater than a predetermined amount, and if the condition determination process determines that the condition is met, it performs a maintenance process on some of the nozzle rows of the plurality of nozzle rows, causing liquid to be discharged from the nozzles in the nozzle rows to the sheet.

[0010] According to the above liquid dispensing device, if the amount of waste liquid exceeds a predetermined amount, maintenance processing is performed on some of the nozzle rows, and liquid is dispensed from the nozzles in the nozzle rows after the maintenance processing. This reduces the amount of liquid consumed during maintenance processing, and even when the remaining amount of liquid is low, liquid can be dispensed onto the sheet after the maintenance processing is performed.

[0011] (3) Preferably, the control unit further performs an abnormality determination process to determine whether the plurality of nozzle rows are normal nozzle rows containing only normal nozzles or abnormal nozzle rows containing one or more abnormal nozzles, and if the condition is determined to be met in the condition determination process and the abnormality determination process determines that the head contains the normal nozzle rows, the control unit may discharge liquid from the nozzles in the normal nozzle rows onto the sheet without performing maintenance processing on the normal nozzle rows.

[0012] (4) Preferably, if the control unit determines in the condition determination process that the conditions are met and in the abnormality determination process that all of the plurality of nozzle rows are abnormal nozzle rows, it may select a predetermined number of nozzle rows with a small number of abnormal nozzles from among the abnormal nozzle rows, perform maintenance processing on the selected nozzle rows, and discharge liquid onto the sheet from the nozzles in the selected nozzle rows.

[0013] (5) Preferably, the liquid dispensing device further comprises a carriage on which the head is mounted and which moves in a second direction, and the control unit may, when dispensing liquid from all nozzles in the plurality of nozzle rows, move the carriage once in the second direction to dispense the liquid, and when dispensing liquid from some of the nozzle rows, move the carriage multiple times in the second direction to dispense the liquid.

[0014] (6) Preferably, the liquid dispensing device further includes a storage unit that stores contract information indicating whether or not a delivery contract for the container has been concluded, and the control unit may perform the maintenance process if the contract information indicates that a delivery contract has been concluded and the container has not been delivered.

[0015] (7) Preferably, the liquid dispensing device further includes a storage unit that stores contract information indicating whether or not a delivery contract for the waste liquid container has been concluded, and the control unit may perform the maintenance process if the contract information indicates that a delivery contract has been concluded and the waste liquid container has not been delivered. [Effects of the Invention]

[0016] According to the present invention, the amount of liquid consumed during maintenance processing can be reduced. [Brief explanation of the drawing]

[0017] [Figure 1] Figure 1 is an external perspective view of a printer 10 according to an embodiment of the present invention. [Figure 2] Figure 2 is a longitudinal cross-sectional view showing the internal structure of the printer 10. [Figure 3] Figure 3 shows the range of movement of the carriage 31. [Figure 4] Figure 4 is a block diagram of printer 10. [Figure 5] Figure 5(A) shows the arrangement of nozzles 33 in head 32, Figure 5(B) is a magnified view of an image printed in high-quality mode, and Figure 5(C) is a magnified view of an image printed in high-speed mode. [Figure 6] Figure 6 is a schematic diagram showing the configuration of the maintenance unit 51. [Figure 7] Figure 7 is a flowchart of the main process. [Figure 8] Figure 8 is a flowchart of the checking process. [Figure 9] Figure 9 is a flowchart of the process using N nozzle arrays. [Figure 10] FIG. 10(A) is a part of the flowchart of the main processing of a printer according to a first modification, FIG. 10(B) is a part of the flowchart of the main processing of a printer according to a second modification, and FIG. 10(C) is a part of the flowchart of the main processing of a printer according to a third modification. MODE FOR CARRYING OUT THE INVENTION

[0018] Hereinafter, embodiments of the present invention will be described. It should be noted 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 without changing the gist of the present invention. In the following description, progress from the start point to the end point of an arrow is expressed as "orientation", and movement back and forth on the line connecting the start point and end point of an arrow is expressed as "direction". In addition, an up-down direction 7 is defined based on a state where the printer 10 is installed to be usable (the state shown in FIG. 1), a front-rear direction 8 is defined with the surface of the printer 10 where an opening 13 is formed as a front surface, and a 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 orthogonal to each other.

[0019] [Overview of Printer 10] The printer 10 according to the present embodiment is an example of a liquid ejection device that ejects ink (an example of a liquid) onto a sheet by an inkjet printing method. The printer 10 is a monochrome printer that ejects black ink onto a sheet.

[0020] The printer 10 has a substantially rectangular parallelepiped housing 11. As shown in FIG. 1 and FIG. 2, inside the housing 11, there are disposed a feed tray 14, a feed roller 21, a transport roller 22, a carriage 31, a head 32 that is mounted on the carriage 31 and has a plurality of nozzles 33, a platen 23 facing the head 32, a discharge roller 24, a discharge tray 15, a sub tank 35, a mounting case 36 capable of mounting a cartridge 37, and a tube 34 that communicates the cartridge 37 mounted in the mounting case 36 with the head 32. The plurality of nozzles 33 are arranged in the front-rear direction 8 on the lower surface of the head 32.

[0021] The printer 10 drives the feed roller 21 and the transport roller 22 to transport the sheet supported on the feed tray 14 along the transport path (shown as a dashed line in Figure 2) to the position of the platen 23. Next, the printer 10 ejects ink supplied from the cartridge 37 mounted in the mounting case 36 via the sub-tank 35 and tube 34 from the nozzle 33 of the head 32. As a result, the ink lands on the sheet supported on the platen 23, and the image to be formed is printed on the sheet. The printer 10 drives the discharge roller 24 to discharge the sheet with the printed image into the discharge tray 15.

[0022] The carriage 31 is supported by two guide rails 48 and 49 that extend in the left-right direction 9, and moves back and forth in the left-right direction 9. While the carriage 31 moves in the left-right direction 9, the printer 10 ejects ink from the nozzles 33 of the head 32. This records an image on a portion of the sheet facing the head 32. Next, the printer 10 transports the sheet on the transport rollers 22 so that the next area to be recorded faces the head 32. By repeatedly performing these processes alternately, an image is recorded on the sheet.

[0023] As shown in Figure 1, the housing 11 has a cover 18 on its front surface 12 and at the rightmost end in the left-right direction 9. An opening (not shown) is formed at the location of the cover 18. The cover 18 is rotatable between a position that closes the opening (the position shown in Figure 1) and a position that opens the opening. A single mounting case 36 is located in the storage space inside the housing 11 that extends beyond the opening. A cartridge 37 containing black ink is mounted in the mounting case 36.

[0024] The cartridge 37 has an ink chamber 38 (see Figure 2) capable of containing ink. When the cartridge 37 is installed in the mounting case 36, the ink contained in the ink chamber 38 flows into the sub-tank 35 via an ink channel 39 that connects the ink chamber 38 and the sub-tank 35. The sub-tank 35 temporarily stores the incoming ink. The ink contained in the sub-tank 35 is supplied to the head 32 via a tube 34. The sub-tank 35 and cartridge 37 are examples of containers.

[0025] [Ink level sensor 41] As shown in Figure 2, an ink level sensor 41 is located on the rear surface of the sub-tank 35. The ink level sensor 41 includes a light-emitting element (not shown) and a light-receiving element (not shown) facing each other across the sub-tank 35. For example, the light-emitting element is located on the left side of the sub-tank 35, and the light-receiving element is located on the right side of the sub-tank 35. At least at the location of the ink level sensor 41, the sub-tank 35 is made of a light-transmitting material.

[0026] When the ink level in the sub-tank 35 is below the position of the ink level sensor 41, light emitted from the light-emitting element is incident on the light-receiving element. At this time, the ink level sensor 41 outputs, for example, a low-level signal. On the other hand, when the ink level in the sub-tank 35 is above the position of the ink level sensor 41, the light emitted from the light-emitting element is scattered by the ink in the sub-tank 35, and the amount of light incident on the light-receiving element decreases. At this time, the ink level sensor 41 outputs, for example, a high-level signal. In the following description, the ink level sensor 41 is referred to as ON when it is outputting a high-level signal and OFF when it is outputting a low-level signal.

[0027] In the above explanation, the ink level sensor 41 was assumed to be an optical sensor, but the configuration of the ink level sensor 41 is arbitrary. For example, the ink level sensor 41 may be a float-type sensor or an electrode-type sensor.

[0028] [Carriage 31's movement range] As shown in Figure 3, the platen 23 has a long shape in the left-right direction 9 and is located below the carriage 31 in the up-down direction 7 (see Figure 2). The left end of the platen 23 is located near the left end of the guide rails 48 and 49 in the left-right direction 9. The right end of the platen 23 is located to the right of the center of the guide rails 48 and 49 in the left-right direction 9. The maintenance section 51 is located to the right of the platen 23 in the left-right direction 9.

[0029] The maintenance unit 51 includes four caps 52. While the printer 10 is printing, the carriage 31 moves left and right within the range of the platen 23. When the printer 10 is not printing, the carriage 31 is positioned so that the head 32 faces the four caps 52 (hereinafter referred to as the standby position).

[0030] [Control Unit 60] Inside the enclosure 11 is the control unit 60 shown in Figure 4. The control unit 60 includes a CPU 61, ROM 62, RAM 63, EEPROM 64, and ASIC 65. ROM 62 stores programs and other information for the CPU 61 to execute various processes. RAM 63 is used as a temporary storage area for data and signals used by the CPU 61 when executing programs, or as a work area for data processing. EEPROM 64 stores information that should be retained even after the power is turned off. RAM 63 and EEPROM 64 are examples of storage units.

[0031] The EEPROM 64 stores contract information. A delivery contract may be concluded between the user of the printer 10 and the manufacturer or distributor of the printer 10, stipulating that when the ink level in the cartridge 37 becomes low, the cartridge 37 will be automatically delivered to the user. The contract information stored in the EEPROM 64 indicates whether or not a delivery contract for the cartridge 37 has been concluded. The contract information stored in the EEPROM 64 is copied to the RAM 63 when the printer 10 is powered on.

[0032] The control unit 60 controls the feed roller 21, transport roller 22, discharge roller 24, carriage 31, and head 32. The control unit 60 rotates the feed roller 21, transport roller 22, and discharge roller 24 by driving a motor (not shown) via the ASIC 65. The control unit 60 moves the carriage 31 in the left-right direction 9 by driving a motor (not shown) via the ASIC 65. The control unit 60 ejects ink from the nozzle 33 of the head 32 by outputting a drive signal to the drive element (not shown) of the head 32 via the ASIC 65. The ASIC 65 outputs a drive signal corresponding to the amount of ink to be ejected from the nozzle 33.

[0033] The control unit 60 receives the signal output from the ink level sensor 41 via the ASIC 65. Based on the signal received from the ink level sensor 41, the control unit 60 determines whether the condition that the amount of ink stored in the sub-tank 35 is less than a predetermined amount is met.

[0034] The control unit 60 controls each part of the maintenance unit 51. The control unit 60 moves the cap 52 vertically 7 by driving a motor (not shown) via the ASIC 65. The control unit 60 switches the state of the flow path switching unit 54 by outputting a control signal via the ASIC 65. The control unit 60 operates the pump 55 by outputting a control signal via the ASIC 65. The configuration of the maintenance unit 51 will be described later.

[0035] The ASIC65 is connected to a display unit 16 and an operation panel 17. The display unit 16 is, for example, a liquid crystal display or an organic EL display. The display unit 16 displays, for example, the status of the printer 10 on its screen. The operation panel 17 outputs operation signals to the control unit 60 in response to user operations. The operation panel 17 may have, for example, push buttons or a touch sensor superimposed on the display unit 16.

[0036] [Arrangement of nozzle 33] Figure 5(A) shows the arrangement of the nozzles 33 on the head 32. In Figure 5(A), the horizontal direction is the direction of movement of the carriage 31, and the vertical direction is the direction of sheet transport. In the following description, the former will be referred to as the main scanning direction, and the latter as the sub-scanning direction. In this embodiment, the main scanning direction and the sub-scanning direction are orthogonal. The white circles shown in Figure 5(A) indicate the position of the nozzles 33 when the head 32 is viewed from above.

[0037] The head 32 includes a first nozzle row K1, a second nozzle row K2, a third nozzle row K3, and a fourth nozzle row K4. The first nozzle row K1 consists of multiple nozzles 33 arranged at a pitch P in the sub-scanning direction (an example of the first direction). The second to fourth nozzle rows K2 to K4 each consist of the same number of nozzles 33 as the first nozzle row K1, arranged at the same pitch P in the sub-scanning direction. In this embodiment, the pitch P is 1 / 300 inch. The second nozzle row K2 is located to the right of the first nozzle row K1. The third nozzle row K3 is located to the right of the second nozzle row K2. The fourth nozzle row K4 is located to the right of the third nozzle row K3. The distance between two nozzle rows in the main scanning direction is arbitrary.

[0038] The sub-scanning position of nozzle 33 in the second nozzle row K2 is shifted by 1 / 4 of the pitch P (i.e., 1 / 1200 of an inch) from the sub-scanning position of nozzle 33 in the first nozzle row K1. The sub-scanning position of nozzle 33 in the third nozzle row K3 is shifted by 1 / 2 of the pitch P from the sub-scanning position of nozzle 33 in the first nozzle row K1. The sub-scanning position of nozzle 33 in the fourth nozzle row K4 is shifted by 3 / 4 of the pitch P from the sub-scanning position of nozzle 33 in the first nozzle row K1.

[0039] The nozzles 33 in the first to fourth nozzle rows K1 to K4 are divided into groups of four in the order of their arrangement in the sub-scanning direction, and the four nozzles 33 within each group correspond to one another. For example, the nozzles 33 located in the first to fourth rows correspond to one another, and the nozzles 33 located in the fifth to eighth rows correspond to one another.

[0040] Although Figure 5(A) shows four nozzles 33 for each nozzle row, the actual number of nozzles 33 within each nozzle row is more than four. Also, while the head 32 is shown to contain four nozzle rows, the head 32 may contain two, three, or five or more nozzle rows.

[0041] In addition to forming multiple nozzles 33 on the head 32 such that their positions in the sub-scanning direction differ for each nozzle row, there is another method for arranging multiple nozzles 33 in the configuration shown in Figure 5(A): forming multiple nozzles 33 on the head 32 such that their positions in the sub-scanning direction are the same across the nozzle rows, and then tilting the head 32 by a small angle (rotating it by a small angle in the horizontal plane) and attaching it to the carriage 31.

[0042] [Printer 10 operating modes] The printer 10 operates in either high-quality mode or high-speed mode. Figure 5(B) shows a magnified image printed in high-quality mode. Figure 5(C) shows a magnified image printed in high-speed mode. The black circles shown in Figures 5(B) and 5(C) represent dots made by ink ejected from the nozzles 33.

[0043] In high-quality mode (Figure 5(B)), the carriage 31 moves at a predetermined speed in the main scanning direction, and ink is ejected from nozzles 33 in the first to fourth nozzle rows K1 to K4 each time the carriage 31 moves 1 / 600 of an inch in the main scanning direction. In this case, one line of the image is formed by a group of dots made by the ink ejected from one nozzle 33. Therefore, in high-quality mode, an image with a resolution of 600 dpi in the main scanning direction and a resolution of 1200 dpi in the sub-scanning direction is formed on the sheet.

[0044] In high-speed mode (Figure 5(C)), the carriage 31 moves at a faster speed in the main scanning direction than in high-quality mode, and ink is ejected from the nozzles 33 in the first to fourth nozzle rows K1 to K4 each time the carriage 31 moves 1 / 300 of an inch in the main scanning direction. However, the ink ejection timing from the nozzles 33 in the second nozzle row K2 and the fourth nozzle row K4 is delayed so that the landing position of the ink ejected from these nozzles 33 is shifted by 1 / 600 of an inch in the main scanning direction of the carriage 31 relative to the landing position of the ink ejected from the nozzles 33 in the first nozzle row K1 and the third nozzle row K3.

[0045] In this case, one line of the image is formed by a group of dots made from ink ejected from one nozzle 33 and a group of dots made from ink ejected from an adjacent nozzle 33. Specifically, odd-numbered lines of the image are formed by a group of dots made from ink ejected from a nozzle 33 in the first nozzle row K1 and a group of dots made from ink ejected from a nozzle 33 in the second nozzle row K2. Even-numbered lines of the image are formed by a group of dots made from ink ejected from a nozzle 33 in the third nozzle row K3 and a group of dots made from ink ejected from a nozzle 33 in the fourth nozzle row K4. The spacing between dots in the main scanning direction is 1 / 600 of an inch. Therefore, in high-speed mode, an image with a resolution of 600 dpi in the main scanning direction and a resolution of 600 dpi in the sub-scanning direction is printed.

[0046] [Maintenance Department 51] Figure 6 shows the configuration of the maintenance unit 51 and a portion of the head 32 corresponding to one nozzle row. On the underside of the head 32 are the first to fourth nozzle rows K1 to K4, each containing multiple nozzles 33 arranged in the sub-scanning direction. Figure 6 shows one of these nozzle rows. When the carriage 31 is in the standby position, the cap 52 faces the nozzle row. Inside the head 32, an ink channel 72 is formed, connecting the ink inlet 71 and the nozzles 33.

[0047] The cap 52 moves up and down between a position in contact with the lower surface of the head 32 (hereinafter referred to as the covering position) and a position spaced apart from the lower surface of the head 32 (hereinafter referred to as the spaced position), according to control from the control unit 60. When the carriage 31 is in the standby position, the cap 52 is in the covering position. At this time, the cap 52 contacts the periphery of the nozzle row and covers the nozzle row. When the carriage 31 is in a position other than the standby position, the cap 52 is in the spaced position. At this time, the cap 52 is in a position spaced downward from the periphery of the nozzle row.

[0048] The bottom of the cap 52 has an outlet 53. The internal space of the cap 52 is connected to a terminal of the flow path switching unit 54 via the outlet 53. Another terminal of the flow path switching unit 54 is connected to the internal space of another cap 52 corresponding to another nozzle row. Another terminal of the flow path switching unit 54 is connected to one end of the pump 55. The flow path switching unit 54 connects one of the internal spaces of the four caps 52 to one end of the pump 55. The other end of the pump 55 is connected to a waste liquid tank 56. The waste liquid tank 56 contains the ink discharged from the head 32 as waste liquid during maintenance. The waste liquid tank 56 is an example of a waste liquid container.

[0049] With the cap 52 in the covered position, the internal space of the cap 52 is connected to the pump 55 by the flow path switching unit 54, and the pump 55 is driven, thereby applying suction pressure from the nozzle 33 to the ink flow path 72. As a result, the ink and gas in the ink flow path 72 are discharged from the nozzle 33. The ink discharged from the nozzle 33 is collected as waste liquid in the waste liquid tank 56. In this way, purging is performed on the nozzles 33 in the nozzle row.

[0050] The control unit 60 controls the maintenance unit 51 to perform purging as a maintenance process for the head 32. The control unit 60 controls the flow path switching unit 54 to perform purging on one or more nozzle rows selected from the first to fourth nozzle rows K1 to K4. Purging is an example of a maintenance process.

[0051] [Abnormal nozzle array and discharge detection process] In printer 10, a nozzle 33 fails to eject. In the following explanation, a nozzle that fails to eject is referred to as an "abnormal nozzle," a nozzle that does not fail to eject is referred to as a "normal nozzle," a nozzle row containing one or more abnormal nozzles is referred to as an "abnormal nozzle row," and a nozzle row containing only normal nozzles is referred to as a "normal nozzle row."

[0052] The printer 10 may or may not have an ejection detection function to detect ejection failures of the nozzles 33. In the printer 10 with an ejection detection function, the control unit 60 performs ejection detection processing as needed.

[0053] [Main process] The control unit 60 performs various processes by having the CPU 61 execute a program stored in the RAM 63. In high-speed mode, the control unit 60 performs the main process shown in Figure 7. If a condition is met during the execution of the main process, the control unit 60 performs a check process (Figure 8) and an N-nozzle row usage process (Figure 9). The 1-nozzle row usage flag (indicated as a flag in the drawings) is used in the main process and the check process. The 1-nozzle row usage flag is set to ON when image recording is performed using one nozzle row, and to OFF when image recording is performed using four nozzle rows.

[0054] The main processing performed by the control unit 60 is explained with reference to Figure 7. As shown in Figure 7, the control unit 60 determines whether or not to perform a manual purge at the beginning of the main processing (S11). In S11, the control unit 60 decides to perform a manual purge, for example, if it receives a purge instruction from the user. In response to its decision to perform a manual purge (S11: Yes), the control unit 60 proceeds to S12. In this case, the control unit 60 sets the flag to OFF (S12) and proceeds to S11.

[0055] If the control unit 60 determines in S11 that it will not perform a manual purge (S11: No), it proceeds to S13. In this case, the control unit 60 determines whether or not there is a print job (S13). In S13, the control unit 60 determines, for example, whether or not there is a print job in the print queue. If the control unit 60 determines that there is no print job (S13: No), it proceeds to S11.

[0056] In response to determining in S13 that there is a print job (S13: Yes), the control unit 60 proceeds to S14. In this case, the control unit 60 determines whether the ink level sensor 41 is OFF or not (S14). The ink level sensor 41 being OFF indicates that the amount of ink stored in the sub-tank 35 is less than a predetermined amount. S14 is an example of a conditional judgment process. In response to determining that the ink level sensor 41 is OFF (S14: Yes), the control unit 60 proceeds to S15. In this case, the control unit 60 determines whether the printer 10 has an ink ejection detection function or not (S15).

[0057] The control unit 60, having determined that the ejection detection function exists (S15: Yes), proceeds to S16. In this case, the control unit 60 determines whether the check execution conditions are met (S16). The check execution conditions are the conditions for determining whether or not the check process in S20 needs to be executed. For example, the check execution conditions may be that 100 or more pages have been printed since the last ejection detection. Alternatively, the check execution conditions may be that it is the first print since 6:00 AM. The check execution conditions may also be other conditions or a combination of multiple conditions.

[0058] If the control unit 60 determines that the check execution conditions are not met (S16: No), it proceeds to S17. In this case, the control unit 60 determines whether the 1 nozzle row use flag is ON or OFF (S17). If the control unit 60 determines that the 1 nozzle row use flag is not ON (is OFF) (S17: No), it proceeds to S18. In this case, the control unit 60 sets the number of nozzle rows used N to 4 and executes the N nozzle row use process (S18).

[0059] In response to determining in S17 that the 1 nozzle row usage flag is ON (S17: Yes), the control unit 60 proceeds to S19. In this case, the control unit 60 sets the number of nozzle rows to use N to 1 and executes the N nozzle row usage process (S19). In the subsequent S26, the control unit 60 uses the same nozzle row that was used in the previous operation.

[0060] If the control unit 60 determines in S16 that the check execution conditions are met (S16: Yes), it proceeds to S20. In this case, the control unit 60 executes the check process shown in Figure 8 (details will be described later) (S20).

[0061] In response to determining in S15 that there is no ejection detection function (S15: No), the control unit 60 proceeds to S21. In this case, the control unit 60 determines whether or not pre-print purging is necessary (S21). In S21, the control unit 60 determines that pre-print purging is necessary, for example, if it is necessary to ensure that printing is performed.

[0062] The control unit 60, in response to determining that pre-print purging is necessary (S21: Yes), proceeds to S22. In this case, the control unit 60 performs purging on the first nozzle row K1 (S22). Next, the control unit 60 sets the first nozzle row K1 as the nozzle row to be used (S23). Next, the control unit 60 sets the number of nozzle rows to be used N to 1 and performs the N-nozzle row usage process (S24).

[0063] In S14, the control unit 60 determines that the ink level sensor 41 is not OFF (the amount of ink stored in the sub-tank 35 is equal to or greater than a predetermined amount) (S14: No), and proceeds to S25. In S21, the control unit 60 determines that pre-print purging is not necessary (S21: No), and proceeds to S25. In these cases, the control unit 60 sets the number of nozzle rows used N to 4 and executes the N-nozzle row usage process (S25).

[0064] After executing S18, S19, S20, S24, or S25, the control unit 60 proceeds to S26. Next, the control unit 60 performs the recording process (S26) and proceeds to S11. In S26, the control unit 60 performs the recording process by ejecting ink from the nozzles 33 in the nozzle row onto the sheet.

[0065] [Checking process] Referring to Figure 8, the check process performed by the control unit 60 is explained. The check process is performed when the printer 10 has an ejection detection function. As shown in Figure 8, the control unit 60 performs an ejection detection process at the beginning of the check process (S31). In S31, the control unit 60 ejects a small amount of ink from all nozzles 33 in the first to fourth nozzle rows K1 to K4, and detects whether an ejection failure has occurred in each nozzle 33 based on the current level or voltage level of the drive signal supplied to the head 32 at that time. Based on the above detection result, the control unit 60 determines whether the first to fourth nozzle rows K1 to K4 are normal nozzle rows or abnormal nozzle rows.

[0066] Next, the control unit 60 determines whether all of the first to fourth nozzle rows K1 to K4 are normal nozzle rows (S32). If the control unit 60 determines that all are normal nozzle rows (S32: Yes), it proceeds to S33. In this case, the control unit 60 sets the 1 nozzle row use flag to OFF (S33), sets the number of nozzle rows to use N to 4, and executes the N nozzle row use process (S34).

[0067] If the control unit 60 determines in S32 that not all nozzle rows are normal (i.e., there are abnormal nozzle rows) (S32: No), it proceeds to S35. In this case, the control unit 60 determines whether or not there are normal nozzle rows among the first to fourth nozzle rows K1 to K4 (S35). If the control unit 60 determines that there are normal nozzle rows (S35: Yes), it proceeds to S36. In this case, the control unit 60 selects the nozzle row with the lowest usage frequency among the normal nozzle rows as the nozzle row to be used (S36). By using the nozzle row with the lowest usage frequency, the usage frequency of the first to fourth nozzle rows K1 to K4 can be equalized, and the degree of deterioration of the first to fourth nozzle rows K1 to K4 can be equalized. Alternatively, in S36, the control unit 60 may determine the nozzle rows to be used from among the normal nozzle rows in the order of K1, K2, K3, and K4.

[0068] In S35, the control unit 60 determines that there are no normal nozzle rows (S35: No) and proceeds to S37. In this case, the control unit 60 selects the nozzle row with the most normal nozzles among the abnormal nozzle rows (i.e., the first to fourth nozzle rows K1 to K4) as the nozzle row to be used (S37). Next, the control unit 60 determines the purge rank (S38). In S38, the control unit 60 determines the purge rank based, for example, on the number or proportion of normal nozzles included in the nozzle row to be used. Next, the control unit 60 performs a purge on the nozzle row to be used (S39). In S39, the control unit 60 performs a purge on the nozzle row to be used selected in S37 with an ink discharge amount corresponding to the rank determined in S38.

[0069] After executing S36 or S39, the control unit 60 proceeds to S40. Next, the control unit 60 sets the 1 nozzle row use flag to ON (S40), sets the number of nozzle rows to use N to 1, and executes the N nozzle row use process (S41). After executing S34 or S41, the control unit 60 terminates the check process.

[0070] In the above explanation, the control unit 60 selected one nozzle row with the fewest abnormal nozzles from the abnormal nozzle row as the usable nozzle row in S37. Alternatively, the control unit 60 may select two or three nozzle rows from the abnormal nozzle row in order of the number of abnormal nozzles being fewest in S37 as the usable nozzle row. In this way, the control unit 60 may select a predetermined number of nozzle rows with the fewest abnormal nozzles from the abnormal nozzle row. Note that S31, S32, and S35 are examples of abnormality detection processing.

[0071] [Processing using N nozzle arrays] The N-nozzle array usage process performed by the control unit 60 will be explained with reference to Figure 9. As shown in Figure 9, at the beginning of the N-nozzle array usage process, the control unit 60 determines whether the number of nozzle arrays to be used is 1 or 4 (S51). The number of nozzle arrays to be used is determined to be 1 when the N-nozzle array usage process is called from S19, S24, or S41, and to be 4 when the N-nozzle array usage process is called from S18, S25, or S34.

[0072] In the N-nozzle row usage process, a transport mode is used. The transport mode indicates how many times the carriage 31 moves left to right when printing a predetermined amount of image data, and is set to 1 pass or 4 passes. If the transport mode is 1 pass, the predetermined amount of image data is printed while the carriage 31 moves left to right once. If the transport mode is 4 passes, the predetermined amount of image data is printed while the carriage 31 moves left to right four times.

[0073] In response to its determination in S51 that there is one nozzle row to use (S51: 1), the control unit 60 proceeds to S52. In this case, the control unit 60 counts the nozzles to be used that are included in the nozzle row to be used (S52). Next, the control unit 60 sets the transport mode to 4 passes (S53). Next, the control unit 60 places the image data into the nozzle row to be used (S54). Next, the control unit 60 displays the change in print control on the display unit 16 (S55) and terminates the N nozzle row usage process.

[0074] In response to its determination in S51 that the number of nozzle rows to be used is four (S51: 4), the control unit 60 proceeds to S56. In this case, the control unit 60 sets the transport mode to 1 pass (S56). Next, the control unit 60 places the image data into the first to fourth nozzle rows K1 to K4 (S57) and terminates the N nozzle row usage process.

[0075] If the control unit 60 determines in S51 that four nozzles are to be used, it sets the transport mode to 4 passes in S56. In this case, in S26, ink is ejected from all nozzles 33 of the first to fourth nozzle rows K1 to K4. On the other hand, if the control unit 60 determines in S51 that one nozzle is to be used, it sets the transport mode to 1 pass in S56. In this case, in S26, ink is ejected from the nozzle 33 of one nozzle row selected from the first to fourth nozzle rows. Thus, when the control unit 60 ejects ink from all nozzles 33 of multiple nozzle rows, it moves the carriage 31 once in the left-right direction 9 to eject the ink, and when it ejects ink from the nozzles 33 of some nozzle rows, it moves the carriage 31 multiple times (four times in this case) in the left-right direction 9 to eject the ink.

[0076] [Effects and Effects] As described above, the printer 10 according to this embodiment includes a sub-tank 35, a head 32 including a plurality of nozzles 33, and a control unit 60. The plurality of nozzles 33 are arranged in the sub-scanning direction to form a plurality of nozzle rows. The control unit 60 performs a condition determination process to determine whether the condition that the amount of ink stored in the sub-tank 35 is less than a predetermined amount is met (S14). If the condition determination process determines that the condition is met (S14: Yes), it performs a purge as a maintenance process for some of the nozzle rows among the plurality of nozzle rows (S39), and performs a recording process by ejecting ink from the nozzles in some of the nozzle rows onto the sheet (S41, S26).

[0077] In this embodiment, the printer 10 performs maintenance on some nozzle rows when the remaining ink level is below a predetermined amount, and then ejects ink from the nozzles 33 in some of the nozzle rows after the maintenance. Therefore, the amount of ink consumed during the maintenance process is reduced, and even when the remaining ink level is low, ink can be ejected onto the sheet after the maintenance process is performed.

[0078] The control unit 60 performs an abnormality determination process to determine whether a plurality of nozzle rows are normal nozzle rows or abnormal nozzle rows (S31). If the condition determination process determines that the conditions are met and the abnormality determination process determines that the head 32 includes normal nozzle rows (S14: Yes, S35: Yes), the control unit 60 performs the recording process by ejecting ink from the nozzles in the normal nozzle rows onto the sheet without purging the normal nozzle rows (S41, S26). In this way, when the head 32 includes normal nozzle rows, the amount of ink consumed by the maintenance process can be further reduced by ejecting ink from the normal nozzle rows without performing maintenance on the normal nozzle rows.

[0079] If the control unit 60 determines in the condition judgment process that the conditions are met and in the abnormality judgment process that all of the multiple nozzle rows are abnormal nozzle rows (S14: Yes, S35: No), it selects a predetermined number of nozzle rows with a small number of abnormal nozzles (in this case, 1) from among the abnormal nozzle rows (S37), performs purging on the selected nozzle rows (S39), and performs recording processing by ejecting ink from the nozzles 33 in the selected nozzle rows onto the sheet (S41, S26). The fewer the number of abnormal nozzles, the less liquid is consumed in the nozzle row maintenance process. Therefore, if all of the multiple nozzle rows are abnormal nozzle rows, the amount of ink consumed in the maintenance process can be further reduced by performing maintenance on the nozzle rows with a small number of abnormal nozzles and ejecting ink from the nozzle rows after the maintenance process.

[0080] When the control unit 60 ejects ink from all nozzles 33 of multiple nozzle rows, it moves the carriage 31 once in the left-right direction 9 to eject the ink. When it ejects ink from some of the nozzle rows 33, it moves the carriage 31 multiple times (four times in this case) in the left-right direction 9 to eject the ink. Therefore, when ejecting ink from some of the nozzle rows 33, it is possible to eject ink onto the sheet with the same resolution as when ejecting ink from all of the nozzle rows 33.

[0081] [Differentiation] Various modifications can be made to the printer 10 according to the above embodiment. In S14, the control unit 60 of the printer 10 determines whether the condition that the amount of ink stored in the sub-tank 35 is less than a predetermined amount is met. In the first modified printer, the control unit may determine whether the condition that the amount of waste liquid stored in the waste liquid tank 56 is equal to or greater than a predetermined amount is met.

[0082] There is a positive correlation between the decrease in the amount of ink stored in the sub-tank 35 and the amount of waste liquid stored in the waste liquid tank 56. That is, when the printer 10 performs printing or purging, the amount of waste liquid stored in the waste liquid tank 56 increases by an amount corresponding to the decrease in the amount of ink stored in the sub-tank 35. The control unit of the printer according to the first modified example calculates the amount of waste liquid stored in the waste liquid tank 56 based on the amount of waste liquid (predicted value) when printing or purging is performed and the amount of evaporation of the ink that has become waste liquid (predicted value). The calculated amount of waste liquid is stored in the RAM 63 and EEPROM 64.

[0083] Similar to the control unit 60 of printer 10, the control unit of the printer according to the first modified example (hereinafter referred to as the control unit in the first modified example) executes the processes shown in Figures 7 to 9. However, the control unit executes S101 shown in Figure 10(A) instead of S14 shown in Figure 7. In S101, the control unit determines whether the waste liquid tank 56 is near full (almost full) based on the calculated amount of waste liquid. Being near full in the waste liquid tank 56 is an example of a situation where the amount of waste liquid contained in the waste liquid tank 56 is equal to or greater than a predetermined amount, and S101 is an example of a condition determination process. Depending on whether the control unit determines that the waste liquid tank 56 is near full (S101: Yes), it proceeds to S15, and depending on whether the control unit determines that the waste liquid tank 56 is not near full (S101: No), it proceeds to S25.

[0084] The printer according to the first modified example comprises a sub-tank 35, a head 32 including a plurality of nozzles 33, a waste liquid tank 56, and a control unit. The plurality of nozzles 33 are arranged in the sub-scanning direction to form a plurality of nozzle rows. The control unit performs a condition determination process to determine whether the amount of waste liquid contained in the waste liquid tank 56 is equal to or greater than a predetermined amount (S101). If it determines that the condition is met, it performs a purge on some of the nozzle rows among the plurality of nozzle rows (S39), and performs a recording process by ejecting ink from the nozzles in some of the nozzle rows onto the sheet (S41, S26).

[0085] In the first modified example, if the amount of waste liquid exceeds a predetermined amount, the printer performs maintenance processing on some nozzle rows and discharges liquid from the nozzles 33 in some nozzle rows after the maintenance processing. Therefore, similar to the printer 10 according to the embodiment, the amount of ink consumed in the maintenance processing is reduced, and ink can be discharged onto the sheet after the maintenance processing is performed, even when the ink level is low.

[0086] The printer according to the second modification is the printer 10 according to the embodiment with the addition of a determination based on whether or not a delivery contract for cartridge 37 has been concluded. Similar to the control unit 60 of printer 10, the control unit of the printer according to the second modification (hereinafter abbreviated as "control unit" in the second modification) executes the processes shown in Figures 7 to 9. However, the control unit executes S201 to S203 shown in Figure 10(B) instead of S14 shown in Figure 7.

[0087] In S201, the control unit determines whether a delivery contract for cartridge 37 has been concluded based on the contract information stored in RAM 63 or EEPROM 64. If the control unit determines that a delivery contract for cartridge 37 has been concluded (S201: Yes), it proceeds to S202. In this case, the control unit determines whether cartridge 37 has not been delivered (S202). In S202, the control unit displays a message such as "Has the cartridge not been delivered?" on the display unit 16 and determines whether cartridge 37 has not been delivered based on the response from the user entered via the operation panel 17.

[0088] The control unit determines that cartridge 37 has not been delivered (S202:Yes) and proceeds to S203. In this case, the control unit determines whether the ink level sensor 41 is OFF or not (S203). The control unit determines that the ink level sensor 41 is OFF (S203:Yes) and proceeds to S15.

[0089] In S201, the control unit determines that a delivery contract for cartridge 37 has not been concluded (S201: No), and proceeds to S25. In S202, the control unit determines that cartridge 37 is not undelivered (has been delivered) (S202: No), and proceeds to S25. In S203, the control unit determines that the ink level sensor 41 is not OFF, and proceeds to S25.

[0090] Thus, the printer according to the second modified example further includes a storage unit (RAM 63, EEPROM 64) that stores contract information indicating whether or not a delivery contract for cartridge 37 has been concluded. The control unit executes the processes from S15 onward if the contract information indicates that a delivery contract for cartridge 37 has been concluded (S201: Yes) and cartridge 37 has not been delivered (S202: Yes). Therefore, if a delivery contract for cartridge 37 has been concluded but cartridge 37 has not been delivered immediately, the amount of ink consumed during maintenance processing can be reduced.

[0091] The control unit may, for example, determine in S201 whether it is certain that the delivery contract for cartridge 37 will be terminated, and in S202 whether the remaining days of the delivery contract are 7 days or less.

[0092] The printer according to the third modification adds a determination based on whether or not a delivery contract for the waste liquid tank 56 has been concluded, compared to the printer according to the first modification. In some cases, a delivery contract may be concluded between the printer user and the printer manufacturer or sales agent, which stipulates that the waste liquid tank 56 will be automatically delivered to the user when the amount of waste liquid contained in the waste liquid tank 56 becomes large. In the printer according to the third modification, the contract information stored in the EEPROM 64 indicates whether or not a delivery contract for the waste liquid tank 56 has been concluded.

[0093] Similar to the control unit 60 of printer 10, the control unit of the printer according to the third modified example (hereinafter referred to as the control unit in the third modified example) executes the processes shown in Figures 7 to 9. However, the control unit executes S301 to S303 shown in Figure 10(C) instead of S14 shown in Figure 7.

[0094] In S301, the control unit determines whether a delivery contract for the waste liquid tank 56 has been concluded based on the contract information stored in RAM 63 or EEPROM 64. If the control unit determines that a delivery contract for the waste liquid tank 56 has been concluded (S301: Yes), it proceeds to S302. In this case, the control unit determines whether the waste liquid tank 56 has not been delivered (S302). In S302, the control unit displays a message on the display unit 16, for example, "Has the waste liquid tank not been delivered?", and determines whether the waste liquid tank 56 has not been delivered based on the response from the user entered via the operation panel 17.

[0095] The control unit determines that the waste liquid tank 56 has not been delivered (S302: Yes) and proceeds to S303. In this case, the control unit determines whether the waste liquid tank 56 is near full or not (S303). The control unit determines that the waste liquid tank 56 is near full (S302: Yes) and proceeds to S15.

[0096] In S301, the control unit determines that a delivery contract for the waste liquid tank 56 has not been concluded (S301: No), and proceeds to S25. In S302, the control unit determines that the waste liquid tank 56 is not undelivered (it has been delivered) (S302: No), and proceeds to S25. In S303, the control unit determines that the waste liquid tank 56 is near full (S303: No), and proceeds to S25.

[0097] Thus, the printer according to the third modified example further includes a storage unit (RAM 63, EEPROM 64) that stores contract information indicating whether or not a delivery contract for the waste liquid tank 56 has been concluded. The control unit executes the processing from S15 onward if the contract information indicates that a delivery contract for the waste liquid tank 56 has been concluded (S301: Yes) and the waste liquid tank 56 is not delivered (S302: Yes). Therefore, if a delivery contract for the waste liquid tank 56 has been concluded but the waste liquid tank 56 is not delivered immediately, the amount of ink consumed during maintenance processing can be reduced.

[0098] The printer 10 according to this embodiment is equipped with a sub-tank 35 and a cartridge 37 as a housing (cartridge model). In the case of a cartridge model printer, a delivery contract for the cartridge 37 and waste ink tank 56 may be concluded between the printer user and the printer manufacturer or sales agent. A modified printer may be equipped with a tank having an ink inlet (tank model). In a tank model printer, new ink is supplied to the printer by the user pouring ink contained in an ink bottle into the tank's inlet. In the case of a tank model printer, a delivery contract for the ink bottle and waste ink tank 56 may be concluded between the printer user and the printer manufacturer or sales agent.

[0099] The printer 10 is configured to perform a purge as a maintenance process for the print head 32. The purge may include a suction purge that sucks out the nozzles 33 in the nozzle row and an exhaust purge that sucks out the exhaust ports corresponding to the nozzle row. Alternatively, the printer 10 may perform a flush instead of a purge as a maintenance process for the print head 32. Furthermore, the modified printer may be equipped with liquid level sensors other than the ink level sensor 41, and a mounting sensor for detecting whether or not a cartridge 37 is installed in the mounting case 36.

[0100] Furthermore, the control unit 60 of the printer 10 according to the embodiment determines that the condition that the amount of ink stored in the sub-tank 35 is less than a predetermined amount is met (S14: Yes), and determines Yes in S15 and S16, No in S32 and S35, or No in S15, Yes in S21, then sets the number of nozzle rows used N to 1, performs maintenance processing (S22, S39), and performs recording processing (S26). Alternatively, the control unit of the modified printer may, when it determines that the condition that the amount of ink stored in the sub-tank 35 is less than a predetermined amount is met, perform maintenance processing and recording processing with the number of nozzle rows used N to 1, regardless of whether other conditions are met. Or, the control unit of the modified printer may, when it determines that the amount of waste liquid stored in the waste liquid tank 56 is equal to or greater than a predetermined amount, perform maintenance processing and recording processing with the number of nozzle rows used N to 1, regardless of whether other conditions are met. [Explanation of Symbols]

[0101] 10. Printer (liquid ejection device) 31...carriage 32 heads 33... Nozzle 35... Sub-tank (container) 37.. Cartridge (container) 56. Waste liquid tank (waste liquid container) 60... Control Unit 63...RAM (memory section) 64...EEPROM (storage unit)

Claims

1. A container for holding liquid, A head including multiple nozzles for discharging the liquid supplied from the above-mentioned container, It comprises a control unit and, The above-mentioned multiple nozzles are arranged in a first direction to form multiple nozzle rows, The above control unit, A conditional determination process is performed to determine whether the condition that the remaining amount of liquid contained in the above container is less than a predetermined amount is met. If the above conditional judgment process determines that the conditions are met, maintenance processing is performed on some of the nozzle rows among the multiple nozzle rows, and liquid is discharged from the nozzles in the nozzle rows onto the sheet. Further abnormality detection processing is performed to determine whether the above-mentioned nozzle rows are normal nozzle rows containing only normal nozzles, or abnormal nozzle rows containing one or more abnormal nozzles. A liquid dispensing device that, if the above condition determination process determines that the conditions are met and the above abnormality determination process determines that the head includes the above normal nozzle row, dispenses liquid from the nozzles in the normal nozzle row onto a sheet without performing maintenance on the above normal nozzle row.

2. A container for holding liquid, A head including multiple nozzles for discharging the liquid supplied from the above-mentioned container, A waste liquid container for collecting the waste liquid discharged from the head, It comprises a control unit and, The above-mentioned multiple nozzles are arranged in a first direction to form multiple nozzle rows, The above control unit, A conditional determination process is performed to determine whether the amount of waste liquid contained in the waste liquid container is equal to or greater than a predetermined amount. If the above conditional judgment process determines that the conditions are met, maintenance processing is performed on some of the nozzle rows among the multiple nozzle rows, and liquid is discharged from the nozzles in the nozzle rows onto the sheet. Further abnormality detection processing is performed to determine whether the above-mentioned nozzle rows are normal nozzle rows containing only normal nozzles, or abnormal nozzle rows containing one or more abnormal nozzles. A liquid dispensing device that, if the above condition determination process determines that the conditions are met and the above abnormality determination process determines that the head includes the above normal nozzle row, dispenses liquid from the nozzles in the normal nozzle row onto a sheet without performing maintenance on the above normal nozzle row.

3. The liquid dispensing device according to claim 1 or 2, wherein the control unit determines in the condition determination process that the conditions are met and in the abnormality determination process that all of the plurality of nozzle rows are abnormal nozzle rows, selects a predetermined number of nozzle rows with a small number of abnormal nozzles from among the abnormal nozzle rows, performs maintenance processing on the selected nozzle rows, and dispenses liquid from the nozzles in the selected nozzle rows onto the sheet.

4. The above head is mounted, and a carriage that moves in a second direction is further provided, The liquid dispensing device according to claim 1 or 2, wherein the control unit moves the carriage once in the second direction to dispense liquid when dispensing liquid from all nozzles in the plurality of nozzle rows, and moves the carriage multiple times in the second direction to dispense liquid when dispensing liquid from some of the nozzles in the nozzle rows.

5. The system further includes a storage unit that stores contract information indicating whether or not a delivery contract for the above-mentioned container has been concluded. The liquid dispensing device according to claim 1, wherein the control unit indicates that the contract information indicates that the delivery contract has been concluded and the container has not been delivered, and the control unit performs the maintenance process.

6. The system further includes a storage unit that stores contract information indicating whether or not a delivery contract for the above-mentioned waste liquid container has been concluded. The liquid dispensing device according to claim 2, wherein the control unit indicates that the contract information indicates that the delivery contract has been concluded and the waste liquid container has not been delivered, and the control unit performs the maintenance process.

Images