Printing device, control method of printing device, and computer program

Abstract

To provide a printing device capable of reducing an amount of waste liquid while suppressing non-ejection of a head.SOLUTION: A printing device 10 includes: an inkjet head 20 including a nozzle surface 22 on which a nozzle 21 configured to eject ink is opened; a cap 51 configured to come into tight contact with the nozzle surface 22; a cleaning liquid tank 53 configured to be connected to the cap 51 through a cleaning liquid flow path 54, and store a cleaning liquid; a waste liquid tank 58 configured to be connected to the cap 51 through a waste liquid flow path 59, and store a waste liquid including at least one of the ink or the cleaning liquid supplied to the cap 51; and a controller 70. The controller 70 is configured to selectively perform first maintenance processing of the nozzle 21 using the cleaning liquid, and second maintenance processing of the nozzle 21 using the cleaning liquid, the second maintenance processing having a smaller amount of the waste liquid than the first maintenance processing.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present disclosure relates to a printing device that ejects ink from a nozzle surface, a control method for a printing device, and a computer program. [Background technology]

[0002] A liquid ejection device disclosed in Patent Document 1 is known as a conventional printing device. This liquid ejection device includes a head having a nozzle surface where nozzles open, a suction cap that covers the nozzle surface, a liquid discharge path connected to the suction cap, and a suction pump provided in the liquid discharge path. In a head maintenance and recovery operation, when the suction pump is driven with the liquid discharge path closed and the nozzle surface covered by the suction cap, the inside of the suction cap becomes negative pressure, and ink is sucked from the nozzles into the suction cap. Then, when the inside of the suction cap reaches the operating pressure of the check valve of the suction pump, the check valve opens and cleaning liquid is supplied into the suction cap to clean the suction cap and the nozzle surface. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2022-179991 A Summary of the Invention [Problem to be solved by the invention]

[0004] In the liquid ejection device of Patent Document 1, ink is sucked from the nozzles by the suction operation of a suction pump and the nozzle surface is cleaned with cleaning liquid, thereby preventing non-ejection of the head. However, there is a problem in that waste liquid containing at least one of the ink and cleaning liquid is generated.

[0005] The present disclosure has been made to solve such problems, and aims to provide a printing device, a control method for a printing device, and a computer program that can reduce the amount of waste liquid while suppressing non-ejection from the head. [Means for solving the problem]

[0006] A printing device according to one aspect of the present disclosure comprises an inkjet head including a nozzle surface where nozzles that eject ink are opening, a cap that fits tightly to the nozzle surface, a cleaning liquid tank that is connected to the cap via a cleaning liquid flow path and stores cleaning liquid, a waste liquid tank that is connected to the cap via a waste liquid flow path and stores waste liquid including at least one of the ink and cleaning liquid supplied to the cap, and a control unit, wherein the control unit selectively performs a first maintenance process for the nozzles using cleaning liquid and a second maintenance process for the nozzles that uses cleaning liquid and produces a smaller amount of waste liquid than the first maintenance process.

[0007] A control method for a printing device according to one aspect of the present disclosure includes an inkjet head including a nozzle surface where nozzles that eject ink are open, a cap that is in close contact with the nozzle surface, a cleaning liquid tank that is connected to the cap via a cleaning liquid flow path and stores cleaning liquid, and a waste liquid tank that is connected to the cap via a waste liquid flow path and stores waste liquid including at least one of the ink and cleaning liquid supplied to the cap, and selectively performs a first maintenance process for the nozzles using cleaning liquid and a second maintenance process for the nozzles that uses cleaning liquid and produces a smaller amount of waste liquid than the first maintenance process.

[0008] A computer program according to one aspect of the present disclosure causes a printing device including an inkjet head including a nozzle surface through which nozzles that eject ink are opened, a cap in close contact with the nozzle surface, a cleaning liquid tank connected to the cap via a cleaning liquid flow path and for storing cleaning liquid, and a waste liquid tank connected to the cap via a waste liquid flow path and for storing waste liquid including at least one of ink and cleaning liquid supplied to the cap, to selectively perform a first maintenance process for the nozzles using cleaning liquid and a second maintenance process for the nozzles using cleaning liquid and producing a smaller amount of waste liquid than the first maintenance process. Effect of the Invention

[0009] According to the present disclosure, in the first maintenance process and the second maintenance process, the nozzle face in close contact with the cap is cleaned by the cleaning liquid supplied to the cap, so that non-ejection of the nozzles open on the nozzle face can be suppressed. Furthermore, the second maintenance process can suppress non-ejection of the nozzles while reducing the amount of waste liquid. [Brief description of the drawings]

[0010] [Figure 1] 1 is a perspective view of a printing device according to an embodiment of the present disclosure. [Diagram 2] FIG. 2 is a functional block diagram illustrating a configuration of a printing device. [Diagram 3] FIG. 2 is a diagram illustrating a schematic diagram of a head and a maintenance device. [Figure 4] Fig. 4A is a flow chart showing an example of a first maintenance process, and Fig. 4B is a flow chart showing an example of a second maintenance process. [Diagram 5] FIG. 11 is a diagram for explaining an ink suction operation. [Figure 6] FIG. 11 is a diagram for explaining a first waste liquid suction operation. [Figure 7] 11A and 11B are diagrams for explaining a first cleaning liquid introducing operation. [Figure 8]Fig. 8A is a diagram showing a pump drive period during which the first cleaning liquid is introduced in the first maintenance process, and Fig. 8B is a diagram showing a pump drive period during which the second cleaning liquid is introduced in the second maintenance process. [Figure 9] 13A and 13B are diagrams for explaining a second waste liquid suction operation. [Figure 10] 13 is a diagram for explaining a third waste liquid suction operation. FIG. [Figure 11] FIG. 11 is a diagram for explaining a wipe operation. [Figure 12] 13A and 13B are diagrams for explaining the second cleaning liquid introducing operation. [Figure 13] Fig. 13A is a top view of the cap into which the cleaning liquid has been introduced in the first cleaning liquid introducing operation, Fig. 13B is a top view of the cap into which the cleaning liquid has been introduced in the second cleaning liquid introducing operation, and Fig. 13C is a top view of the cap into which the cleaning liquid has moved in the second waste liquid suction operation. [Figure 14] 10 is a flowchart illustrating an example of maintenance of a printing device. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings. In the following, the same or corresponding elements are denoted by the same reference numerals throughout the drawings, and duplicated descriptions thereof will be omitted.

[0012] <Printing device> 1 and 2, a printing device 10 according to an embodiment of the present disclosure is an inkjet printer that ejects ink onto a print medium A and prints an image on the print medium A. For example, when a fabric is used as the print medium A, the printing device 10 is a garment printer.

[0013] The printing device 10 includes an inkjet head (hereinafter, referred to as a head) 20. The head 20 includes a first head 20a and a second head 20b. As shown in FIG. 3, the first head 20a includes a plurality of first nozzles 21a and a first nozzle surface 22a, which is a lower surface where the first nozzles 21a are open. Furthermore, as shown in FIG. 2, the first head 20a has a first driving element 23a. The first driving element 23a is, for example, a piezoelectric element, and is provided for each of the first nozzles 21a, and applies pressure to the first ink of the first head 20a to eject the first ink from the first nozzles 21a. The first nozzles 21a eject the first ink onto the printing medium A by driving the first driving element 23a. The first ink is, for example, a color ink such as cyan ink, magenta ink, yellow ink, and black ink.

[0014] As shown in Fig. 3, the second head 20b has a plurality of second nozzles 21b and a second nozzle surface 22b which is the lower surface where the second nozzles 21b open. Furthermore, as shown in Fig. 2, the second head 20b has a second driving element 23b. The second driving element 23b is, for example, a piezoelectric element, and is provided for each second nozzle 21b, and applies pressure to the second ink of the second head 20b to eject the second ink from the second nozzles 21b.

[0015] The second nozzle 21b ejects the second ink onto the print medium A by driving the second driving element 23b. The second ink is an ink different from the first ink and dries more easily than the first ink, for example, a white ink. The white ink contains a pigment such as titanium oxide and dries more easily than the color inks. In the following, the first nozzle 21a and the second nozzle 21b may be referred to as nozzles 21, and the first nozzle surface 22a and the second nozzle surface 22b may be referred to as nozzle surface 22.

[0016] Furthermore, as shown in FIG. 1 and FIG. 2, the printing device 10 includes a moving device 30 that moves the first head 20a and the second head 20b. The moving device 30 includes a carriage 31, an endless belt 32, a moving motor 33, and a pair of rails 34. The carriage 31 carries the first head 20a and the second head 20b, is supported by the pair of rails 34, and is connected to the endless belt 32. The pair of rails 34 extend in the left-right direction with a gap between them in the front-rear direction. The endless belt 32 extends in the left-right direction and is connected to the moving motor 33 via a pulley. When the moving motor 33 is driven, the endless belt 32 runs, and the carriage 31, the first head 20a, and the second head 20b move in the left-right direction along the rails 34.

[0017] Furthermore, the printing device 10 is equipped with a transport device 40 that transports the print medium A. The transport device 40 has a platen 41, a linear actuator, and a transport motor 42. The platen 41 is flat, and the print medium A is placed on its upper surface. The linear actuator has, for example, a ball screw and a nut combined with it, and the nut is connected to the platen 41, and the ball screw is connected to the transport motor 42. When the transport motor 42 is driven, the nut moves in the front-rear direction relative to the ball screw, and accordingly, the platen 41 and the print medium A move in the front-rear direction.

[0018] Furthermore, the printing device 10 includes a maintenance device 50 for the head 20, as shown in Figs. 2 and 3. The maintenance device 50 includes a cap 51 and a cap displacement device 52. The cap 51 is made of an elastic member such as rubber, has a rectangular parallelepiped shape, and has an internal space and an opening to the internal space provided at the top. The cap 51 includes a first cap 51a and a second cap 51b. The first cap 51a is disposed below the first nozzle surface 22a of the first head 20a. The second cap 51b is disposed below the second nozzle surface 22b of the second head 20b.

[0019] The cap displacement device 52 is provided on each of the first head 20a and the second head 20b. The cap displacement device 52 of the first head 20a displaces (for example, moves up and down) the first cap 51a between a close contact position where the first cap 51a is in close contact with the first nozzle face 22a and a spaced position where the first cap 51a is spaced from the first nozzle face 22a. The cap displacement device 52 of the second head 20b displaces (for example, moves up and down) the second cap 51b between a close contact position where the second cap 51b is in close contact with the second nozzle face 22b and a spaced position where the second cap 51b is spaced from the second nozzle face 22b.

[0020] In this contact position, the upper end of the first cap 51a contacts the first nozzle surface 22a, and the upper opening of the internal space of the first cap 51a is covered by the first nozzle surface 22a. Also, the upper end of the second cap 51b contacts the second nozzle surface 22b, and the upper opening of the internal space of the second cap 51b is covered by the second nozzle surface 22b. Meanwhile, in the separated position, the internal space of the first cap 51a is open, and the internal space of the second cap 51b is open.

[0021] Furthermore, the maintenance device 50 has a waste liquid tank 58, a waste liquid flow path 59, a waste liquid valve 60, and a pump 61. Furthermore, each of the caps 51, the first cap 51a and the second cap 51b, has an outlet 51d. One end of the waste liquid flow path 59 is connected to the outlet 51d of the cap 51, and the other end is connected to the waste liquid tank 58. The internal space of the cap 51 is in communication with the waste liquid tank 58 via the outlet 51d and the waste liquid flow path 59. The waste liquid tank 58 stores waste liquid that is discharged from the internal space of the cap 51 and contains at least one of ink and cleaning liquid.

[0022] Further, the waste liquid valve 60 is provided in the waste liquid flow path 59, and the pump 61 is provided in the waste liquid flow path 59 between the waste liquid valve 60 and the waste liquid tank 58. When the pump 61 is driven with the waste liquid valve 60 open and the waste liquid flow path 59 open, the internal space of the cap 51 is sucked through the waste liquid flow path 59. As a result, the waste liquid in the internal space of the cap 51 is discharged from the discharge port 51d through the waste liquid flow path 59 to the waste liquid tank 58. The pump 61 is driven with its suction force variable. The greater the suction force of the pump 61, the lower the pressure in the internal space of the cap 51. On the other hand, when the waste liquid valve 60 is closed, the waste liquid flow path 59 is closed and the waste liquid is not discharged to the waste liquid tank 58.

[0023] The waste liquid flow path 59 includes a first waste liquid flow path 59a connected to the first cap 51a and a second waste liquid flow path 59b connected to the second cap 51b. A waste liquid valve 60 is provided in each of the first waste liquid flow path 59a and the second waste liquid flow path 59b, and a waste liquid tank 58 is also connected to each of them. In the example of FIG. 3, the first waste liquid flow path 59a and the second waste liquid flow path 59b are connected to different waste liquid tanks 58, but they may be connected to the same waste liquid tank 58. The pump 61 includes a first pump 61a provided in the first waste liquid flow path 59a and sucking the inside of the first cap 51a, and a second pump 61b provided in the second waste liquid flow path 59b and sucking the inside of the second cap 51b.

[0024] Furthermore, the maintenance device 50 has a cleaning liquid tank 53, a cleaning liquid flow path 54, a downstream cleaning liquid valve 55, an air release valve 56, and an upstream cleaning liquid valve 57. Furthermore, each of the caps 51, the first cap 51a and the second cap 51b, has a supply port 51c. One end of the cleaning liquid flow path 54 is connected to the supply port 51c of the cap 51 and communicates with the internal space of the cap 51, and the other end is connected to the cleaning liquid tank 53. The cleaning liquid tank 53 stores the cleaning liquid and supplies the cleaning liquid from the supply port 51c through the cleaning liquid flow path 54 to the internal space of the cap 51. The cleaning liquid contains, for example, a component that dissolves ink.

[0025] The upstream cleaning liquid valve 57 and the downstream cleaning liquid valve 55 are provided in the cleaning liquid flow path 54. The downstream cleaning liquid valve 55 is disposed downstream of the upstream cleaning liquid valve 57 in the flow of cleaning liquid in the cleaning liquid flow path 54. When the downstream cleaning liquid valve 55 is closed, it reduces the inflow of waste liquid containing at least one of ink and cleaning liquid in the internal space of the cap 51 into the cleaning liquid flow path 54.

[0026] Furthermore, when the downstream cleaning liquid valve 55 and the upstream cleaning liquid valve 57 are open and the cleaning liquid flow path 54 between the cleaning liquid tank 53 and the supply port 51c of the cap 51 is open, if the pump 61 is driven, the cleaning liquid flows from the cleaning liquid tank 53 through the cleaning liquid flow path 54 and via the supply port 51c into the internal space of the cap 51. On the other hand, if at least one of the downstream cleaning liquid valve 55 and the upstream cleaning liquid valve 57 is closed, the cleaning liquid flow path 54 is closed and the cleaning liquid does not flow into the internal space of the cap 51.

[0027] The atmosphere release valve 56 is provided in a branch path of the cleaning liquid flow path 54 between the downstream cleaning liquid valve 55 and the upstream cleaning liquid valve 57, and has an atmosphere release port 561. When the atmosphere release port 561 is opened, the cleaning liquid flow path 54 is opened to the atmosphere. When the downstream cleaning liquid valve 55 and the atmosphere release port 561 are opened and the pump 61 is driven, air flows from the atmosphere release port 561 through the cleaning liquid flow path 54 and via the supply port 51c into the internal space of the cap 51. On the other hand, when at least one of the downstream cleaning liquid valve 55 and the atmosphere release port 561 is closed, air does not flow into the internal space of the cap 51.

[0028] The cleaning liquid flow path 54 includes a first cleaning liquid flow path 54a connected to the first cap 51a and a second cleaning liquid flow path 54b connected to the second cap 51b. The first cleaning liquid flow path 54a and the second cleaning liquid flow path 54b are each provided with a downstream cleaning liquid valve 55, a downstream cleaning liquid valve 55, an air release valve 56, and an upstream cleaning liquid valve 57. The first cleaning liquid flow path 54a and the second cleaning liquid flow path 54b are each connected to a cleaning liquid tank 53. In the example of FIG. 3, the first cleaning liquid flow path 54a and the second cleaning liquid flow path 54b are connected to different cleaning liquid tanks 53, but they may be connected to the same cleaning liquid tank 53.

[0029] 2 and 11, the maintenance device 50 has a wiper 62 and a wiper displacement device 63. The wiper 62 is made of an elastic member such as rubber, has a flat plate shape, for example, and is disposed below the nozzle surface 22 of the head 20 in the vertical direction and between the platen 41 and the cap 51 in the horizontal direction, for example.

[0030] The wiper displacement device 63 displaces (for example, moves up and down) the wiper 62 between a contact position where the wiper 62 contacts the nozzle surface 22 and a separated position where the wiper 62 is separated from the nozzle surface 22. When the head 20 is moved by the carriage 31 with the nozzle surface 22 in contact with the wiper 62 arranged at this contact position, the nozzle surface 22 is wiped by the wiper 62, and the ink on the nozzle surface 22 is removed by the wiper 62.

[0031] The maintenance device 50 is provided with a wiper 62 that wipes the first nozzle face 22a, and a wiper 62 that wipes the second nozzle face 22b. The maintenance device 50 is also provided with a wiper displacement device 63 that displaces the wiper 62 with respect to the first nozzle face 22a, and a wiper displacement device 63 that displaces the wiper 62 with respect to the second nozzle face 22b.

[0032] 2, the printing device 10 further includes a control unit 70, a storage unit 71, an interface 72, and an input device 73 connected to the control unit 70. The interface 72 connects to other external devices such as a PC and a storage medium, and transmits and receives data between the control unit 70 and the external devices. The input device 73 inputs data to the control unit 70 through user operations such as button keys and a touch pad.

[0033] The storage unit 71 is a memory accessible from the control unit 70, and includes a RAM and a ROM. The storage unit 71 stores computer programs for performing various data processing such as printing processing and maintenance processing, and data used in data processing such as print data. The print data includes image data (e.g., raster data) that indicates an image to be printed on the print medium A. The print data may be stored in the storage unit 71, or may be acquired from an external device via the interface 72. The computer programs and data may be stored in a single storage unit 71, or may be divided and stored in multiple storage units 71.

[0034] The control unit 70 is a computer and includes a processor such as a CPU. The control unit 70 executes a computer program stored in the storage unit 71 to control each unit of the printing device 10 and execute various data processing of the printing device 10. The control unit 70 may be configured as a single device that performs centralized control, or may be configured as multiple devices that perform distributed control.

[0035] <Printing process> In such a printing device 10, the control unit 70 executes a printing process based on the print data. In the printing process, the control unit 70 alternates between a pass in which ink is ejected from the nozzles 21 of the head 20 and a conveyance in which the print medium A is conveyed forward or backward while moving the head 20 to the right or left. In this way, ink is ejected onto the print medium A, and an image is printed. Here, a base layer is formed on the print medium A by the second ink, and an image layer is formed on the base layer by the first ink. Note that the first ink and the second ink may be ejected in the same pass, or a pass in which the second ink is ejected may be followed by a pass in which the first ink is ejected.

[0036] <Maintenance processing> For example, when ink adhering to the nozzle surface 22 dries and enters the nozzle 21, non-ejection of ink from the nozzle 21 may occur. Furthermore, when ink adhering to the nozzle surface 22 dries, the wiping performance of the wiper 62 that wipes the nozzle surface 22 may decrease. Furthermore, when ink adhering to the cap 51 dries, it may clog the waste liquid flow path 59. In order to reduce such defects, a maintenance process for the nozzle 21 is performed using a cleaning liquid that dissolves ink. However, the maintenance process for the nozzle 21 generates waste liquid containing at least one of ink and cleaning liquid. Therefore, the printing device 10 selectively performs a first maintenance process for the nozzle 21 using a cleaning liquid and a second maintenance process for the nozzle 21 using a cleaning liquid and generating a smaller amount of waste liquid than the first maintenance process, so as to suppress non-ejection of the nozzle 21 and reduce the amount of waste liquid.

[0037] <First maintenance process> The first maintenance process is executed by the control unit 70 according to the flowchart shown in the example of FIG. 4A. In the first maintenance process, the control unit 70 first executes an ink suction operation (step S1). In the ink suction operation, the control unit 70 places the cap 51 in a contact position and contacts the cap 51 with the nozzle surface 22, as shown in FIG. 5, to cover the internal space of the cap 51 with the nozzle surface 22. In this state, the control unit 70 closes the downstream cleaning liquid valve 55, the air release valve 56, and the upstream cleaning liquid valve 57. This closes the cleaning liquid flow path 54 between the supply port 51c of the cap 51 and the cleaning liquid tank 53 and the air release port 561. The control unit 70 may close the cleaning liquid flow path 54 by closing the downstream cleaning liquid valve 55 without closing the air release valve 56 and the upstream cleaning liquid valve 57.

[0038] Then, the control unit 70 opens the waste liquid valve 60 to open the waste liquid flow path 59. When the control unit 70 drives the pump 61, the pump 61 sucks the internal space of the cap 51 through the waste liquid flow path 59. This reduces the pressure in the internal space of the cap 51, and ink is ejected from the nozzles 21 of the nozzle surface 22 exposed to this internal space. Therefore, even if the nozzles 21 are in a non-ejection state due to thickened ink caused by drying, the thickened ink is discharged from the nozzles 21, so that non-ejection of the nozzles 21 can be suppressed. Such ink and thickened ink are discharged as waste liquid from the nozzles 21 into the cap 51, and are discharged from the discharge port 51d of the cap 51 through the waste liquid flow path 59 to the waste liquid tank 58. Then, the control unit 70 stops the pump 61.

[0039] Subsequently, the control unit 70 executes a first waste liquid suction operation as a first maintenance process after such an ink suction operation (step S2). In the first waste liquid suction operation, as shown in FIG. 6, the cap 51 is in close contact with the nozzle surface 22, and the upper opening of the internal space of the cap 51 is covered by the nozzle surface 22. In this state, the control unit 70 closes the upstream cleaning liquid valve 57 and opens the atmosphere release valve 56 and the downstream cleaning liquid valve 55. As a result, the cleaning liquid flow path 54 between the supply port 51c of the cap 51 and the cleaning liquid tank 53 is closed, but the cleaning liquid flow path 54 between the supply port 51c of the cap 51 and the atmosphere release port 561 is opened. As a result, the atmosphere release port 561 and the internal space of the cap 51 communicate with each other. Since the specific gravity of air is smaller than that of the cleaning liquid, the atmosphere release valve 56 and the downstream cleaning liquid valve 55 may be opened, and the upstream cleaning liquid valve 57 may be opened.

[0040] Then, when the control unit 70 drives the pump 61 while opening the waste liquid valve 60 and opening the waste liquid flow path 59, the internal space of the cap 51 is sucked through the waste liquid flow path 59. The flow path resistance of air in the cleaning liquid flow path 54 communicating with the internal space of the cap 51 is smaller than the flow path resistance of ink in the nozzle 21 communicating with this internal space of the cap 51. As a result, while the ejection of ink from the nozzle 21 is reduced, air flows from the atmosphere opening port 561 through the cleaning liquid flow path 54 into the internal space of the cap 51, so that the waste liquid in the cap 51 is discharged from the discharge port 51d of the cap 51 through the waste liquid flow path 59 to the waste liquid tank 58.

[0041] Next, the control unit 70 executes a first cleaning liquid introduction operation as a first maintenance process after the first waste liquid suction operation (step S3). In the first cleaning liquid introduction operation, as shown in FIG. 7, the cap 51 is in close contact with the nozzle surface 22, and the upper opening of the internal space of the cap 51 is covered by the nozzle surface 22. In this state, the control unit 70 closes the atmosphere release valve 56 and opens the downstream cleaning liquid valve 55 and the upstream cleaning liquid valve 57. As a result, the atmosphere release port 561 is closed, but the cleaning liquid flow path 54 between the supply port 51c of the cap 51 and the cleaning liquid tank 53 is opened. As a result, the cleaning liquid tank 53 and the internal space of the cap 51 are in communication with each other.

[0042] Then, when the control unit 70 drives the pump 61 while opening the waste liquid valve 60 and opening the waste liquid flow path 59, the internal space of the cap 51 is sucked through the waste liquid flow path 59. As a result, the cleaning liquid is introduced from the cleaning liquid tank 53 through the cleaning liquid flow path 54 into the internal space of the cap 51, and the inner surface forming the internal space of the cap 51 and the nozzle surface 22 exposed to the internal space of the cap 51 are cleaned by the cleaning liquid introduced into the internal space.

[0043] As a result, the dried ink adhering to the inner surface of the cap 51 is removed by the cleaning liquid, and malfunctions such as clogging of the waste liquid flow path 59, which suppresses malfunctions such as non-ejection of ink from the nozzles 21 and deterioration of the wiping performance of the wiper 62 caused by the dried ink, can be suppressed. Also, the dried ink adhering to the nozzle surface 22 is removed by the cleaning liquid, and malfunctions such as non-ejection of the nozzles 21 and deterioration of the wiping performance of the wiper 62 caused by the dried ink can be suppressed. Also, even if there is a nozzle 21 among the nozzles 21 that is open to the nozzle surface 22 and whose non-ejection is not resolved even by the ink suction operation, the thickened ink in the nozzle 21 is removed by the cleaning liquid, and thus malfunctions of the nozzle 21 can be suppressed.

[0044] In this first cleaning liquid introducing operation, the control unit 70 intermittently drives the pump 61. For example, as shown in Fig. 8A, the control unit 70 continuously drives the pump 61 during a first drive period a, and then stops the pump 61 during a stop period b. The control unit 70 repeats the continuous drive of the pump 61 during the first drive period a a predetermined number of times (e.g., three times) while stopping the pump 61 between the continuous drives of the pump 61.

[0045] During the stop of the pump 61 between the successive drives of the pump 61, the pressure in the internal space of the cap 51 rises due to a small amount of air entering the cap 51. As a result, in the first cleaning liquid introduction operation, when the pump 61 is intermittently driven including the stop period b, the pressure in the internal space of the cap 51 is less likely to become lower than a predetermined pressure that causes a meniscus break in the nozzle 21 due to suction by the pump 61 than when the pump 61 is continuously driven without the stop period b. Therefore, the control unit 70 can introduce the cleaning liquid into the internal space of the cap 51 while reducing the occurrence of a meniscus break. Therefore, in addition to the ink suction operation, the first cleaning liquid introduction operation also suppresses the ejection of ink from the nozzle 21 due to a meniscus break. Therefore, an increase in the amount of waste liquid containing ink can be reduced.

[0046] Subsequently, the control unit 70 executes a second waste liquid suction operation as a first maintenance process after the first cleaning liquid introduction operation (step S4). In the second waste liquid suction operation, as shown in FIG. 9, the cap 51 is in close contact with the nozzle surface 22, and the upper opening of the internal space of the cap 51 is covered by the nozzle surface 22. In this state, the control unit 70 closes the upstream cleaning liquid valve 57 and opens the atmosphere release valve 56 and the downstream cleaning liquid valve 55. As a result, the cleaning liquid flow path 54 between the supply port 51c of the cap 51 and the cleaning liquid tank 53 is closed, but the cleaning liquid flow path 54 between the supply port 51c of the cap 51 and the atmosphere release port 561 is opened. As a result, the atmosphere release port 561 and the internal space of the cap 51 are in communication with each other.

[0047] Then, when the control unit 70 drives the pump 61 while opening the waste liquid valve 60 and opening the waste liquid flow path 59, the internal space of the cap 51 is sucked through the waste liquid flow path 59. As a result, air flows from the atmosphere opening port 561 through the cleaning liquid flow path 54 into the internal space of the cap 51, so that ink is not sucked from the nozzles 21 and the cleaning liquid in the cap 51 is discharged as waste liquid from the discharge port 51d of the cap 51 through the waste liquid flow path 59 to the waste liquid tank 58. Then, the control unit 70 stops the pump 61.

[0048] Subsequently, the control unit 70 executes a third waste liquid suction operation as a first maintenance process after the second waste liquid suction operation (step S5). In the third waste liquid suction operation, as shown in Fig. 10, the control unit 70 places the cap 51 in the separated position and separates the cap 51 from the nozzle surface 22, so that the internal space of the cap 51 is opened to the atmosphere. In this state, the control unit 70 closes the downstream cleaning liquid valve 55, the atmosphere release valve 56, and the upstream cleaning liquid valve 57 to close the cleaning liquid flow path 54 between the supply port 51c of the cap 51 and the cleaning liquid tank 53 and the atmosphere release port 561.

[0049] Then, when the control unit 70 drives the pump 61 while opening the waste liquid valve 60 and opening the waste liquid flow path 59, the internal space of the cap 51 is sucked through the waste liquid flow path 59. As a result, the cleaning liquid remaining in the internal space of the cap 51 is discharged as waste liquid from the discharge port 51d of the cap 51 through the waste liquid flow path 59 to the waste liquid tank 58.

[0050] Next, the control unit 70 executes a wiping operation as a first maintenance process after the third waste liquid suction operation (step S6). In the wiping operation, as shown in Fig. 11, the control unit 70 places the wiper 62 at the contact position and moves the head 20 right or left by the carriage 31. As a result, the nozzle surface 22 of the head 20 moves right or left while in contact with the wiper 62, and is wiped by the wiper 62, and the ink and cleaning liquid on the nozzle surface 22 are removed by the wiper 62. This makes it possible to suppress non-ejection of ink due to the ink and cleaning liquid remaining on the nozzle surface 22.

[0051] Then, after the wiping operation, the control unit 70 covers the upper opening of the internal space of the cap 51 with the nozzle surface 22. In this way, since the nozzle surface 22 is covered with the cap 51, it is possible to suppress drying of ink in the nozzles 21 that open to the nozzle surface 22 and non-ejection of ink caused by drying.

[0052] <Second maintenance process> The second maintenance process is executed by the control unit 70 according to the flowchart shown in the example of Fig. 4B. In the flowchart of Fig. 4B, the processes of steps S1 and S2 in the flowchart of Fig. 4A are not executed, and step S7 is executed instead of step S3. Therefore, in the second maintenance process, steps S4 to S6 are executed following step S7.

[0053] Specifically, in the second maintenance process, the control unit 70 does not execute the ink suction operation and the first waste liquid suction operation, but executes the second cleaning liquid introduction operation instead of the first cleaning liquid introduction operation (step S7). In the second cleaning liquid introduction operation, the control unit 70 places the cap 51 in the contact position and contacts the cap 51 with the nozzle surface 22, as shown in FIG. 12, to cover the internal space of the cap 51 with the nozzle surface 22. In this state, the control unit 70 closes the air release valve 56 and opens the downstream cleaning liquid valve 55 and the upstream cleaning liquid valve 57. As a result, the air release port 561 is closed, but the cleaning liquid flow path 54 between the supply port 51c of the cap 51 and the cleaning liquid tank 53 is opened. As a result, the cleaning liquid tank 53 and the internal space of the cap 51 are in communication with each other.

[0054] Then, when the control unit 70 drives the pump 61 while opening the waste liquid valve 60 and opening the waste liquid flow path 59, the internal space of the cap 51 is sucked through the waste liquid flow path 59. As a result, the cleaning liquid is introduced from the cleaning liquid tank 53 through the cleaning liquid flow path 54 into the internal space of the cap 51, and the nozzle surface 22 exposed to the internal space of the cap 51 is cleaned by the cleaning liquid introduced into the internal space. As a result, the thickened ink inside the nozzles 21 on the nozzle surface 22 is removed by the cleaning liquid, thereby preventing non-ejection of the nozzles 21.

[0055] In this second cleaning liquid introducing operation, the control unit 70 drives the pump 61 so that the suction force of the pump 61 is greater than that in the first cleaning liquid introducing operation. Since the inside of the cap 51 is suctioned by this pump 61, the pressure in the internal space of the cap 51 in the second cleaning liquid introducing operation becomes lower than the pressure in the internal space of the cap 51 in the first cleaning liquid introducing operation.

[0056] For example, the pressure in the internal space of the cap 51 becomes lower than a predetermined pressure that causes a meniscus break in the nozzle 21. Therefore, the second cleaning liquid introduction operation causes a meniscus break and introduces the cleaning liquid into the internal space of the cap 51. This meniscus break causes the viscous ink to be ejected from the nozzle 21, and the viscous ink is removed from the nozzle 21 by the cleaning liquid. As a result, non-ejection of the head 20 can be suppressed.

[0057] Next, the control unit 70 executes a second waste liquid suction operation as a second maintenance process after the second cleaning liquid introduction operation (step S4). This second waste liquid suction operation is the second maintenance process and is similar to the first maintenance process. Therefore, by the second waste liquid suction operation, the ink and cleaning liquid in the cap 51 are discharged as waste liquid from the discharge port 51d of the cap 51 through the waste liquid flow path 59 to the waste liquid tank 58.

[0058] In this manner, in the second maintenance process, the second cleaning liquid introduction operation in step S7 and the second waste liquid suction operation in step S4 are executed. In the second cleaning liquid introduction operation, the control unit 70 continuously drives the pump 61. For example, as shown in FIG. 8B, in the second cleaning liquid introduction operation, the control unit 70 continuously drives the pump 61 once for the second drive period c.

[0059] The second drive period c, which is the total drive period of the pump 61 in the second cleaning liquid introduction operation, is longer than one first drive period a in the intermittent operation of the pump 61 in the first cleaning liquid introduction operation shown in FIG. 8A. The second drive period c is shorter than the total drive period of the pump 61 in the first cleaning liquid introduction operation, that is, the sum of all the first drive periods a (for example, 3a). As a result, the suction force of the pump 61 in the second cleaning liquid introduction operation is lower than the suction force of the pump 61 in the first cleaning liquid introduction operation. Therefore, the pressure in the internal space of the cap 51 due to the suction of the pump 61 in the second cleaning liquid introduction operation is higher than the pressure in the internal space of the cap 51 due to the suction of the pump 61 in the first cleaning liquid introduction operation. Therefore, the amount of cleaning liquid introduced into the internal space of the cap 51 is likely to be smaller in the second cleaning liquid introduction operation than in the first cleaning liquid introduction operation.

[0060] For example, in the first cleaning liquid introduction operation, the entire internal space of the cap 51 is more likely to be filled with the cleaning liquid as shown in FIG. 13A than in the second cleaning liquid introduction operation. In contrast, in the second cleaning liquid introduction operation, as shown in FIG. 13B, a portion (for example, two-thirds of the entire) of the internal space of the cap 51 is filled with the cleaning liquid, and the remaining portion is more likely to be filled with air. This cleaning liquid flows from the supply port 51c into the internal space of the cap 51, the upper opening of which is covered by the nozzle surface 22, and is filled in a portion of the cap 51 closer to the supply port 51c than the discharge port 51d. In the portion closer to the supply port 51c, both the nozzle surface 22 and the bottom surface of the cap 51 facing the nozzle surface 22 are more likely to be wetted with the cleaning liquid than the portion farther from the supply port 51c. Therefore, the nozzle surface 22 and the cap 51 are cleaned with the cleaning liquid in a portion closer to the supply port 51c than the discharge port 51d.

[0061] Then, in the second waste liquid suction operation after the second cleaning liquid operation, the internal space of cap 51 is sucked by pump 61 via exhaust port 51d while the upper opening of the internal space of cap 51 remains covered by nozzle surface 22, and air flows into the internal space of cap 51 from supply port 51c. As a result, as shown in Fig. 13C, it is considered that the cleaning liquid moves from supply port 51c to exhaust port 51d in the internal space of cap 51 while wetting both nozzle surface 22 and the bottom surface of cap 51. As a result, the nozzle surface 22 and the cap 51 are cleaned by the cleaning liquid in a portion closer to exhaust port 51d than to supply port 51c.

[0062] In this way, since the amount of cleaning liquid introduced in the second cleaning liquid introduction operation is small, the amount of waste liquid including cleaning liquid can be reduced. Furthermore, since the cleaning liquid moves in the internal space of the cap 51 in the second cleaning liquid introduction operation and the second waste liquid suction operation, the entire nozzle surface 22 exposed to the internal space of the cap 51 is cleaned with the cleaning liquid, and non-ejection of the nozzles 21 opening in the nozzle surface 22 can be suppressed.

[0063] Next, the control unit 70 executes the second waste liquid suction operation, followed by a third waste liquid suction operation and a wiping operation in this order as a second maintenance process (steps S5 to S6). The third waste liquid suction operation and the wiping operation in this second maintenance process are the same as the operations in the first maintenance process. Therefore, the third waste liquid suction operation causes the ink and cleaning liquid in the cap 51 to be discharged as waste liquid from the discharge port 51d of the cap 51 through the waste liquid flow path 59 to the waste liquid tank 58. Also, the wiping operation causes the wiper 62 to remove the ink and cleaning liquid on the nozzle surface 22.

[0064] The control unit 70 may simultaneously execute the third waste liquid suction operation and the wiping operation in the second maintenance process. In this way, by executing the third waste liquid suction operation and the wiping operation in parallel, the execution time of the second maintenance process can be shortened compared to executing the third waste liquid suction operation and the wiping operation consecutively.

[0065] <Printing device maintenance procedure> Maintenance of the printing device 10 is performed by the control unit 70 in accordance with the flowchart shown in the example of Fig. 14. This maintenance may be performed each time a predetermined condition is satisfied, such as after each printing process or at a predetermined interval.

[0066] First, the control unit 70 acquires the amount of ink ejection from the storage unit 71 (step S10). For example, a first number x, which is the number of sheets of the print medium A on which printing is performed using the ink, may be used as the amount of ink ejection. In this case, the control unit 70 accumulates the number of printed sheets of the print medium A each time the printing process is performed after reset, and stores this accumulated number in the storage unit 71 as the first number x. This first number x is used as a counter for the first maintenance process, and is reset when the first maintenance process is performed.

[0067] Next, the control unit 70 executes a judgment process to judge whether or not the amount of ink discharged satisfies the non-discharge condition (step S11). The non-discharge condition is, for example, that the first number x of the print medium A is a first predetermined number, for example, 24 or more. In this case, in the judgment process, the control unit 70 judges whether or not the first number x of the print medium A acquired in step S10 is the first predetermined number or more. Here, if the first number x of the print medium A is the first predetermined number or more, the control unit 70 judges that the amount of ink discharged satisfies the non-discharge condition (step S11: YES). On the other hand, if the first number x of the print medium A is less than the first predetermined number, the control unit 70 judges that the amount of ink discharged does not satisfy the non-discharge condition (step S11: NO).

[0068] Next, if the control unit 70 determines in the determination process of step S11 that the amount of ink ejection satisfies the non-ejection condition (step S11: YES), it executes a first maintenance process for the first nozzles 21a and the second nozzles 21b (step S12). In this first maintenance process, the control unit 70 executes the operations of steps S1 to S6 shown in FIG. 4A for each of the first nozzles 21a and the second nozzles 21b.

[0069] Then, the first maintenance process is executed for each of the first nozzle 21a and the second nozzle 21b. Therefore, after the execution of the first maintenance process, the control unit 70 resets the first number x, which is a counter for the first maintenance process, and the second number y, which is a counter for the second maintenance process described below, to 0.

[0070] On the other hand, in the judgment process of step S11, when the control unit 70 judges that the ink ejection amount does not satisfy the non-ejection condition (step S11: NO), the control unit 70 acquires the ejection amount of the second ink from the storage unit 71 (step S13). This ejection amount of the second ink is the amount of the second ink ejected from the second nozzle 21b in the previous printing process executed immediately before the execution of the maintenance process. For this reason, the control unit 70 acquires the print data of the previous printing process stored in the storage unit 71, and acquires the dot size and the number of dots of the second ink in the printing process based on the print data. Then, the control unit 70 acquires the product of the ejection amount of the second ink corresponding to the dot size and the number of ejections of the second ink corresponding to the number of dots as the ejection amount of the second ink.

[0071] Next, the control unit 70 determines whether the ejection amount of the second ink is a predetermined amount, for example, 8 cc or more (step S14). If the control unit 70 determines that the ejection amount of the second ink is the predetermined amount or more (step S14: YES), it executes a second maintenance process for the second nozzles 21b (step S15). In this second maintenance process, the control unit 70 executes the operations of steps S7 and S4 to S6 shown in FIG. 4B for the second nozzles 21b. Note that the second maintenance process is not executed for the first nozzles 21a.

[0072] In the second cleaning liquid introduction operation of step S7, the control unit 70 introduces the cleaning liquid into the second cap 51b by suctioning the inside of the second cap 51b while the second cap 51b is in close contact with the second nozzle surface 22b and the second cleaning liquid flow path 54b is open. As a result, even if the second nozzles 21b are prone to non-ejection due to the second ink that dries easily, the second nozzle surface 22b where the second nozzles 21b open is cleaned with the cleaning liquid, so that non-ejection of the second nozzles 21b can be suppressed.

[0073] In the second maintenance process, the ink suction operation for the first nozzle 21a and the second nozzle 21b and the second cleaning liquid introduction operation for the first nozzle 21a are not performed. As a result, ink is not ejected from the first nozzle 21a and the second nozzle 21b by the ink suction operation, and cleaning liquid is not introduced into the first cap 51a by the second cleaning liquid introduction operation. This makes it possible to reduce the amount of waste liquid including ink and cleaning liquid.

[0074] In this way, when the second maintenance process is performed, the control unit 70 does not reset the first number x, which is a counter for the first maintenance process, to 0, but resets the second number y, which is a counter for the second maintenance process, to 0. This second number y is the number of sheets of print media A on which ink is printed. The second number y of print media A is reset by performing the second maintenance process, and the number of sheets of print media A printed by the printing process is accumulated each time a printing process is performed thereafter, and the accumulated number is stored in the memory unit 71 by the control unit 70 as the second number y.

[0075] On the other hand, in the determination process of step S14, if the control unit 70 determines that the ejection amount of the second ink is less than the predetermined amount (step S14: NO), it acquires the second number y of the print media A from the storage unit 71 (step S16). Then, the control unit 70 determines whether the second number y of the print media A is a second predetermined number, for example, 6 or more (step S17). Here, if the second number y of the print media A is the second predetermined number or more (step S17: YES), the control unit 70 executes a second maintenance process for the second nozzle 21b (step S15). This makes it possible to reduce the amount of waste liquid including ink and cleaning liquid while suppressing non-ejection of the second nozzle 21b.

[0076] Then, after performing the second maintenance process, the control unit 70 resets the second number y, which is a counter for the maintenance process of the second nozzle 21b, to 0 without resetting the first number x, which is a counter for the maintenance process of the first nozzle 21a, to 0.

[0077] On the other hand, in the determination process of step S17, if the second number y of the print media A is less than the second predetermined number (step S17: NO), the control unit 70 executes a wiping operation on the first nozzle surface 22a and the second nozzles 21b (step S18). This wiping operation removes the ink and cleaning liquid on the first nozzle surface 22a and the second nozzles 21b with the wiper 62, thereby suppressing non-ejection of ink due to the ink and cleaning liquid remaining on the first nozzle surface 22a and the second nozzles 21b.

[0078] After the wiping operation is performed, the control unit 70 does not reset the first number x and the second number y, which are counters for the maintenance process. After the first maintenance process of S12, the second maintenance process of S15, and the wiping operation are performed, the control unit 70 ends the maintenance and covers the first nozzle surface 22a with the first cap 51a and the second nozzle 21b with the second cap 51b.

[0079] As shown in the maintenance of the printing device 10 described above, the control unit 70 selectively executes a first maintenance process or a second maintenance process as a maintenance process for the nozzles 21, depending on whether or not the amount of ink ejected satisfies the non-ejection condition. Here, if the amount of ink ejected from both the first nozzle 21a and the second nozzle 21b satisfies the non-ejection condition that is likely to cause non-ejection, the first maintenance process is executed for both the first nozzle 21a and the second nozzle 21b. In contrast, if the amount of ink ejected does not satisfy the non-ejection condition, the second maintenance process is not executed for the first nozzle 21a, and the second maintenance process is executed for the second nozzle 21b that is more likely to cause non-ejection than the first nozzle 21a.

[0080] As a result, because the second nozzles 21b are subjected to the maintenance process more frequently than the first nozzles 21a, non-ejection of the second nozzles 21b can be suppressed even in cases where the second nozzles 21b are prone to non-ejection due to the second ink that dries more easily than the first ink. On the other hand, for the first nozzles 21a that eject the first ink that dries more slowly than the second ink, the number of times the maintenance process is executed is kept lower than for the second nozzles 21b, and the amount of waste liquid can be reduced.

[0081] Furthermore, the first predetermined number for determining whether to perform the first maintenance process in step S11 is greater than the second predetermined number for determining whether to perform the second maintenance process in step S14. This makes it possible to keep the number of times the maintenance process is performed on the first nozzle 21a low, thereby reducing the amount of waste liquid.

[0082] <Other Modifications> 14, the control unit 70 acquires, for example, the number of sheets of the print medium A to be printed with the ink as the ink ejection amount, but the ink ejection amount is not limited to this. For example, the control unit 70 may acquire, as the ink ejection amount, the amount of ink used to print the print medium A in the previous printing process.

[0083] In this case, the control unit 70 obtains the print data of the previous printing process stored in the storage unit 71 after the previous printing process is executed, and obtains the dot size and number of dots of the inks including the first ink and the second ink in the previous printing process based on the print data. Then, the control unit 70 obtains the product of the ink ejection amount corresponding to the dot size and the number of ejections corresponding to the number of dots as the amount of ink used to print on the print medium A in the previous printing process.

[0084] Then, in the judgment process of step S11, the control unit 70 judges whether the amount of ink used in printing the print medium A in the previous printing process is equal to or greater than a predetermined amount. If the amount of ink used in the previous printing process is equal to or greater than the predetermined amount, the control unit 70 judges that the ink ejection amount satisfies the non-ejection condition. On the other hand, if the amount of ink used in the previous printing process is less than the predetermined amount, the control unit 70 judges that the ink ejection amount does not satisfy the non-ejection condition. Note that the cumulative amount, which is the amount of ink used in printing from the reset to the previous printing process, may be acquired as the ink ejection amount and used in the judgment process of step S11, in addition to the previous printing process.

[0085] In addition, in the determination process of step S11, the control unit 70 uses the ink ejection amount as the ink ejection condition, but the ink ejection condition is not limited to the ink ejection amount. For example, the control unit 70 may use the temperature in the printing device 10 as the ink ejection condition. In this case, if the temperature measured by a thermometer provided in the printing device 10 is equal to or higher than a predetermined temperature, the ink in the nozzle 21 is likely to dry, so the control unit 70 may determine that the ink ejection condition satisfies the non-ejection condition. On the other hand, if the measured temperature is lower than the predetermined temperature, the control unit 70 may determine that the ink ejection condition does not satisfy the non-ejection condition.

[0086] Furthermore, in the determination process of step S11, for example, the control unit 70 may use the humidity in the printing device 10 as the ink ejection condition. In this case, if the humidity measured by a hygrometer provided in the printing device 10 is less than a predetermined humidity, the ink in the nozzles 21 is likely to dry out, and the control unit 70 may determine that the ink ejection condition satisfies the non-ejection condition. On the other hand, if the measured humidity is equal to or greater than the predetermined humidity, the control unit 70 may determine that the ink ejection condition does not satisfy the non-ejection condition.

[0087] Furthermore, in the determination process of step S11, for example, the control unit 70 may use the time that has elapsed since the previous ink ejection as the ink ejection condition. In this case, when ink is ejected from the nozzles 21 by the ink suction operation of the printing process or the first maintenance process, the control unit 70 measures the time that has elapsed since the ejection. If this elapsed time is equal to or longer than a predetermined time, the ink in the nozzles 21 is likely to dry, and therefore the control unit 70 may determine that the ink ejection condition satisfies the non-ejection condition. On the other hand, if the elapsed time is less than the predetermined time, the control unit 70 may determine that the ink ejection condition does not satisfy the non-ejection condition.

[0088] 14, the control unit 70 acquires the ink ejection amount used in the printing process that has already been executed before the process of step S10 is executed, but the ink ejection amount is not limited to this. For example, the control unit 70 may acquire the ink ejection amount to be used in the printing process that is to be executed.

[0089] For example, if this ink ejection amount is the amount of ink to be used in printing on the print medium A in the current printing process to be executed, the control unit 70 may acquire the amount of ink to be used in the current printing process based on the print data when acquiring the current printing data. Thus, the control unit 70 may determine whether or not to execute the first maintenance process in step S11, before executing the current printing process, based on the amount of ink to be ejected in the printing process. Note that the cumulative amount, which is the amount of ink used in printing from the reset to the current printing process, may be acquired as the ink ejection amount, and used in the determination process in step S11, in addition to the current printing process.

[0090] Furthermore, when the amount of ink ejected is the number of sheets of the print medium A, the control unit 70 may acquire the first number x by adding the cumulative number of sheets of the print medium A printed in the printing processes already executed before the execution of the process of step S10 to the number of sheets of the print medium A to be printed in the current printing process to be executed from now on. Thereby, the control unit 70 may determine whether or not to execute the first maintenance process in step S11, before the execution of the current printing process, based on the first number x obtained by adding the number of sheets of the print medium A to be printed in the current printing process from now on.

[0091] Furthermore, in step S13 of FIG. 14, the control unit 70 acquires the ejection amount of the second ink used in the previous printing process that was already executed before the execution of the process of step S13, but the ejection amount of the second ink is not limited to this. For example, the control unit 70 may acquire the ejection amount of the second ink to be used in the current printing process that is to be executed based on the print data. In this case, when the control unit 70 acquires the current print data, it may acquire the ejection amount of the second ink in the current printing process based on this print data. Thereby, the control unit 70 may determine whether or not to execute the second maintenance process in step S14 before the execution of the current printing process based on the amount of the second ink to be ejected in the printing process.

[0092] 14, the control unit 70 acquires the second number y, which is the cumulative number of sheets of the print medium A printed in the printing process already executed before the process of step S16 is executed, but the second number y is not limited to this. For example, the control unit 70 may acquire the second number y by adding the cumulative number of sheets of the print medium A printed in the printing process already executed before the process of step S16 to the number of sheets of the print medium A to be printed in the current printing process to be executed. Thereby, the control unit 70 may determine whether or not to execute the second maintenance process in step S17, before the execution of the current printing process, based on the second number y obtained by adding the number of sheets of the print medium A to be printed in the printing process.

[0093] 14 also includes steps S14 and S17. In this case, if the ejection amount of the second ink is equal to or greater than a predetermined amount (step S14: YES), and if the second number y of the print media A is equal to or greater than the second predetermined number (step S17: YES), the control unit 70 executes the second maintenance process. In contrast, the flowchart in FIG. 14 may include either step S14 or step S17. In this case, if the ejection amount of the second ink is equal to or greater than a predetermined amount (step S14: YES), or if the second number y of the print media A is equal to or greater than the second predetermined number (step S17: YES), the control unit 70 executes the second maintenance process.

[0094] Furthermore, if the second number y of the print media A is less than the second predetermined number (step S17: NO), the control unit 70 executes the wiping operation in step S18, but this operation is not limited to this. For example, the control unit 70 may execute a flushing operation in addition to the wiping operation. Furthermore, the control unit 70 may end the maintenance without executing an operation such as the wiping operation in step S18.

[0095] 14, the control unit 70 acquires the ink ejection amount in step S10, the second ink ejection amount in step S13, and the second number y of print media A in step S16 from the storage unit 71, but the method of acquiring these data is not limited to this. For example, the control unit 70 may acquire these data from the interface 72 and the input device 73, etc.

[0096] It should be noted that many improvements and other embodiments of the present disclosure will be apparent to those skilled in the art from the above description. Therefore, the above description should be construed as merely illustrative and is provided for the purpose of teaching those skilled in the art the best mode for carrying out the present disclosure. Details of the structure and / or function thereof may be substantially modified without departing from the spirit of the present disclosure. [Explanation of symbols]

[0097] 10:Printing device 20: Head 20a: 1st head (head) 20b: 2nd head 21a: First nozzle 21b: Second nozzle 22: Nozzle surface 22a: First nozzle surface 22b: second nozzle surface 51: Cap 51a: 1st Cap 51b: 2nd Cap 53: Cleaning solution tank 54: Cleaning fluid flow path 54a: First cleaning liquid flow path 54b: Second cleaning fluid flow path 58: Waste liquid tank 59: Waste flow path 59a: First waste liquid flow path 59b: Second waste liquid flow path 61: Pump 61a: First pump 61b: Second pump 70: Control section

Claims

1. an inkjet head including a nozzle surface on which nozzles for ejecting ink are formed; a cap that is in close contact with the nozzle surface; a cleaning liquid tank connected to the cap via a cleaning liquid flow path and configured to store a cleaning liquid; a waste liquid tank connected to the cap via a waste liquid flow path and configured to store waste liquid including at least one of the ink and the cleaning liquid supplied to the cap; A control unit; Equipped with the control unit selectively executes a first maintenance process for the nozzle using a cleaning liquid and a second maintenance process for the nozzle using a cleaning liquid and producing a smaller amount of waste liquid than the first maintenance process. Printing device.

2. a pump provided in the waste liquid flow path for sucking the inside of the cap; The control unit is As the first maintenance process, an ink suction operation for suctioning the inside of the cap in a state where the cap is in close contact with the nozzle surface and the cleaning liquid flow path is closed; a first cleaning liquid introducing operation of, after the ink suction operation, sucking inside the cap in a state in which the cap is in close contact with the nozzle surface and the cleaning liquid flow path is open, and introducing cleaning liquid into the cap; Run As the second maintenance process, a second cleaning liquid introduction operation in which, without performing the ink suction operation, the inside of the cap is suctioned in a state in which the cap is in close contact with the nozzle surface and the cleaning liquid flow path is open, and cleaning liquid is introduced into the cap; Execute The printing device of claim 1 .

3. a pump provided in the waste liquid flow path for sucking the inside of the cap; The control unit is As the first maintenance process, a first cleaning liquid introducing operation of suctioning the inside of the cap in a state where the cap is in close contact with the nozzle surface and the cleaning liquid flow path is open, and introducing cleaning liquid into the cap; Run As the second maintenance process, a second cleaning liquid introducing operation for introducing cleaning liquid into the cap by suctioning the inside of the cap in a state in which the cap is in close contact with the nozzle surface and the cleaning liquid flow path is open, during a drive period of the pump that is shorter than that of the first cleaning liquid introducing operation; Execute The printing device of claim 1 .

4. The control unit is execute a determination process for determining whether or not the ink ejection conditions satisfy the non-ejection conditions; When the ink ejection condition satisfies the non-ejection condition in the determination process, the first maintenance process is executed; When the ink ejection conditions do not satisfy the non-ejection conditions in the determination process, the second maintenance process is executed.

4. The printing device according to claim 2 or 3.

5. the control unit determines in the determination process that the ink ejection conditions satisfy the non-ejection conditions when the number of sheets of the print medium to be printed with the ink is equal to or greater than a predetermined number, or when the amount of ink used to print the print medium is equal to or greater than a predetermined amount. The printing device according to claim 4.

6. the control unit suctions the inside of the cap to make the pressure inside the cap lower in the second cleaning liquid introducing operation than in the first cleaning liquid introducing operation. The printing device according to claim 2 .

7. the nozzle surface has a first nozzle surface in which first nozzles that eject a first ink are opened, and a second nozzle surface in which second nozzles that eject a second ink that dries more easily than the first ink are opened; the cap includes a first cap in close contact with the first nozzle face and a second cap in close contact with the second nozzle face, the cleaning liquid flow path includes a first cleaning liquid flow path connected to the first cap and a second cleaning liquid flow path connected to the second cap, the waste liquid flow path includes a first waste liquid flow path connected to the first cap and a second waste liquid flow path connected to the second cap, a first pump provided in the first waste liquid flow path and configured to suck air from within the first cap; a second pump provided in the second waste liquid flow path and configured to suck the inside of the second cap; Further equipped with The control unit is As the first maintenance process, an ink suction operation of suctioning an inside of the first cap in a state where the first cap is in close contact with the first nozzle surface and the first cleaning liquid flow path is closed, and suctioning an inside of the second cap in a state where the second cap is in close contact with the second nozzle surface and the second cleaning liquid flow path is closed; a first cleaning liquid introduction operation, which, after the ink suction operation, introduces cleaning liquid into the first cap by suctioning inside the first cap with the first cap in close contact with the first nozzle face and the first cleaning liquid flow path open, and which introduces cleaning liquid into the second cap by suctioning inside the second cap with the second cap in close contact with the second nozzle face and the second cleaning liquid flow path open; Run As the second maintenance process, a second cleaning liquid introducing operation in which, without performing the ink suction operation and without introducing cleaning liquid into the first cap, the second cap is sucked in a state in which the second cap is in close contact with the second nozzle face and the second cleaning liquid flow path is open, and cleaning liquid is introduced into the second cap; Run The printing device of claim 1 .

8. an inkjet head including a nozzle surface on which nozzles for ejecting ink are formed; a cap that is in close contact with the nozzle surface; a cleaning liquid tank connected to the cap via a cleaning liquid flow path and configured to store a cleaning liquid; a waste liquid tank connected to the cap via a waste liquid flow path and configured to store waste liquid including at least one of the ink and the cleaning liquid supplied to the cap; Equipped with selectively executing a first maintenance process for the nozzle using a cleaning liquid and a second maintenance process for the nozzle using a cleaning liquid and producing a smaller amount of waste liquid than the first maintenance process; A method for controlling a printing device.

9. an inkjet head including a nozzle surface on which nozzles for ejecting ink are formed; a cap that is in close contact with the nozzle surface; a cleaning liquid tank connected to the cap via a cleaning liquid flow path and configured to store a cleaning liquid; a waste liquid tank connected to the cap via a waste liquid flow path and configured to store waste liquid including at least one of the ink and the cleaning liquid supplied to the cap; A printing device comprising: selectively executing a first maintenance process for the nozzle using a cleaning liquid and a second maintenance process for the nozzle using a cleaning liquid and producing a smaller amount of waste liquid than the first maintenance process; Computer program.

Images