Liquid dispensing device

Abstract

Solidification of ink due to contact between ink and treatment liquid in a flow path including a flow path switching mechanism or the like is reduced. [Solution] The droplet ejection device includes a flow path switching mechanism that includes a switching valve having an outlet port and multiple inlet ports and switches between multiple flow paths that connect to the outlet port, and the multiple flow paths include a first waste liquid flow path that connects the processing liquid head to the switching valve and passes processing liquid discharged into the processing liquid cap, a second waste liquid flow path that connects the ink head to the switching valve and passes ink discharged into the ink cap, a first cleaning liquid supply flow path that connects the cleaning liquid tank to the switching valve via the processing liquid cap and passes cleaning liquid, a second cleaning liquid supply flow path that connects the cleaning liquid tank to the switching valve via the ink cap and passes cleaning liquid, and a cleaning liquid bypass flow path that connects the cleaning liquid tank to the switching valve without passing through the processing liquid cap and the ink cap and passes cleaning liquid.

Description

[Technical Field]

[0001] The present disclosure relates to a liquid ejection device used in a printing device such as an inkjet printer. [Background technology]

[0002] A liquid ejection device is known that includes a switching valve that connects a cap port, which communicates with a nozzle cap, to a suction pump when the device is in a standby state where printing or the like is not being performed (Patent Document 1). In this liquid ejection device, if it determines that the flow path member has adhered to the cover due to solidification of ink in the switching valve, the device drives the suction pump to discharge ink from the inkjet head and causes the discharged ink to flow into the switching valve. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2016-193552 Summary of the Invention [Problem to be solved by the invention]

[0004] Before ink is ejected onto a print medium, a pretreatment liquid may be ejected in advance to improve the fixability of the ink to the print medium. However, there is a risk that the ink solidifies when the ink discharged by purging comes into contact with the pretreatment liquid in a flow path that includes a switching valve, etc. This could interfere with the operation of the pump during purging and liquid discharge.

[0005] Therefore, an object of the present disclosure is to provide a liquid ejection device that can reduce solidification of ink due to contact between ink and treatment liquid in a flow path that includes a flow path switching mechanism or the like. [Means for solving the problem]

[0006] The liquid ejection device of the present disclosure includes a treatment liquid head having a treatment liquid nozzle plate in which treatment liquid nozzle holes are opened for ejecting a treatment liquid containing a pre-treatment liquid, a post-treatment liquid, and any one of the pre-treatment liquid and the post-treatment liquid; an ink head having an ink nozzle plate in which ink nozzle holes are opened for ejecting a white ink, a color ink, and an ink containing any one of the white ink and the color ink; a treatment liquid cap covering a treatment liquid nozzle surface which is one surface of the treatment liquid nozzle plate; an ink cap covering an ink nozzle surface which is one surface of the ink nozzle plate; a cleaning liquid tank which stores a cleaning liquid; a plurality of flow paths; a switching valve having an outlet port and a plurality of inlet ports; and a flow path switching mechanism that switches the flow paths that communicate with the outlet port between the plurality of flow paths, wherein the plurality of flow paths include a first waste flow path that connects the treatment liquid head and the switching valve and passes the treatment liquid discharged into the treatment liquid cap, a second waste flow path that connects the ink head and the switching valve and passes the ink discharged into the ink cap, a first cleaning liquid supply flow path that connects the cleaning liquid tank to the switching valve via the treatment liquid cap and passes the cleaning liquid, a second cleaning liquid supply flow path that connects the cleaning liquid tank to the switching valve via the ink cap and passes the cleaning liquid, and a cleaning liquid bypass flow path that connects the cleaning liquid tank to the switching valve without passing through the treatment liquid cap and the ink cap.

[0007] According to the present disclosure, the cleaning liquid bypass flow path allows cleaning liquid in the cleaning liquid tank to be supplied to the switching valve without passing through the treatment liquid cap and the ink cap. The cleaning liquid supplied directly from the cleaning liquid tank to the switching valve in this manner facilitates dilution of the ink and treatment liquid present in the switching valve and the pump connected to the switching valve via a tube. This reduces ink solidification due to contact between the ink and treatment liquid in the flow path including the switching valve. [Effects of the Invention]

[0008] According to the present disclosure, it is possible to provide a liquid ejection device that can reduce solidification of ink due to contact between ink and treatment liquid in a flow path including a flow path switching mechanism or the like. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is a plan view showing a liquid ejection device according to an embodiment. [Figure 2] FIG. 2 is a block diagram showing the configuration of a control system of the liquid ejection device of FIG. [Figure 3] FIG. 3A is a diagram showing the capped state of each head, and FIG. 3B is a diagram showing the uncapped state of each head. [Figure 4] FIG. 4 is a perspective view showing the configuration of the switching valve. [Figure 5] FIG. 5A is a diagram showing the first waste liquid flow path when the pretreatment liquid head is purged, FIG. 5B is a diagram showing the first cleaning liquid supply flow path when the pretreatment liquid head is cleaned, and FIG. 5C is a diagram showing the suction flow path when the pretreatment liquid head is idle suctioned. [Figure 6] FIG. 6A is a diagram showing the second waste liquid flow path when purging the white ink head, FIG. 6B is a diagram showing the second cleaning liquid supply flow path when cleaning the white ink head, and FIG. 6C is a diagram showing the suction flow path when idle suction of the white ink head is performed. [Figure 7] FIG. 7A is a diagram showing the cleaning liquid bypass flow path when the switching valve is being cleaned, and FIG. 7B is a diagram showing the suction flow path when the cleaning liquid bypass flow path is being subjected to idle suction. [Figure 8] FIG. 8 is a flowchart showing the flow of maintenance processing for the pretreatment liquid head and the ink head. [Figure 9] FIG. 9 is a flowchart showing the flow of the maintenance process for the ink heads and the post-treatment liquid heads. [Figure 10] FIG. 10 is a diagram showing an aspect in which the carriage supports the pretreatment liquid head, the white ink head, the color ink heads, and the posttreatment liquid head. [Figure 11]FIG. 11A is a diagram showing a discharge head and a treatment liquid cap and an ink cap corresponding to the discharge head, and FIG. 11B is a diagram showing a discharge head and caps corresponding to the discharge head. DETAILED DESCRIPTION OF THE INVENTION

[0010] A liquid ejection device according to an embodiment of the present disclosure will be described below with reference to the drawings. The liquid ejection device described below is merely one embodiment of the present disclosure. Therefore, the present disclosure is not limited to the following embodiment, and additions, deletions, and modifications are possible within the scope of the present disclosure. Note that, hereinafter, identical or corresponding elements will be designated by the same reference numerals throughout the drawings, and duplicated descriptions will be omitted unless otherwise noted.

[0011] FIG. 1 is a plan view showing a liquid ejection device 100 according to an embodiment. FIG. 2 is a block diagram showing the configuration of a control system for the liquid ejection device 100 of FIG. 1. FIG. 3A is a diagram showing a capped state of the treatment liquid head 22 and the ink head 21, and FIG. 3B is a diagram showing an uncapped state of the treatment liquid head 22 and the ink head 21. In FIGS. 1 and 3, directions that are orthogonal to each other are referred to as a first direction Df, a second direction Ds, and a third direction Dt. In this embodiment, for example, the first direction Df is the transport direction of the print medium W, the second direction Ds is the movement direction of the carriage 41 (described below), and the third direction Dt is the up-down direction. In the following description, Ds is referred to as the movement direction, Df is referred to as the transport direction, and Dt is referred to as the up-down direction. However, the above directions are merely examples and are not limiting.

[0012] 1, the liquid ejection device 100 is applied to an inkjet printer that prints an image on a print medium W, such as printing paper. The liquid ejection device 100 ejects ink or treatment liquid supplied from a tank 12 onto the print medium W. Details of the ink and treatment liquid will be described later.

[0013] The liquid ejection device 100 is, for example, a serial head type. The liquid ejection device 100 includes a platen 11, multiple tanks 12, an ink head 21, a treatment liquid head 22, a conveying device 30, a scanning device 40, a treatment liquid cap 46, an ink cap 47, a cleaning liquid tank 63 (see FIG. 5 below), and a waste liquid tank (see FIG. 5 below). The liquid ejection device 100 may also be a line head type.

[0014] The ink head 21 ejects ink onto the print medium W. Specifically, the ink head 21 ejects white ink, color ink, or ink containing either one of white ink and color ink. Examples of color ink include cyan ink, yellow ink, magenta ink, and black ink. In the example of FIG. 1, the ink head 21 is a white ink head 21w that ejects white ink. The white ink head 21w ejects white ink onto a portion onto which the pretreatment liquid head 22b, described below, ejects pretreatment liquid. Note that the ink head 21 may be a color ink head 21c that ejects color ink. Alternatively, both the white ink head 21w and the color ink head 21c may be provided. In other words, both the white ink head 21w and the color ink head 21c may be provided as the ink head 21. Hereinafter, the term "ink head 21" shall be understood to include both the white ink head 21w and the color ink head 21c.

[0015] The treatment liquid head 22 ejects treatment liquid onto the print medium W. Specifically, the treatment liquid head 22 ejects a pretreatment liquid, a posttreatment liquid, or a treatment liquid containing either one of the pretreatment liquid and the posttreatment liquid. In the example of FIG. 1 , the treatment liquid head 22 is a pretreatment liquid head 22b that ejects a pretreatment liquid as the treatment liquid. The pretreatment liquid head 22b ejects a pretreatment liquid before ink such as white ink is ejected onto the print medium W. The treatment liquid head 22 may be a posttreatment liquid head 22a that ejects a posttreatment liquid as the treatment liquid. In this case, the posttreatment liquid head 22a ejects the posttreatment liquid onto the portion where the color ink has been ejected. Also, both the pretreatment liquid head 22b and the posttreatment liquid head 22a may be provided. In other words, both the pretreatment liquid head 22b and the posttreatment liquid head 22a may be provided as the treatment liquid head 22. Hereinafter, when the treatment liquid head 22 is referred to as a treatment liquid head 22, it is assumed that both the pretreatment liquid head 22b and the posttreatment liquid head 22a are included.

[0016] 3A and 3B, the ink head 21 has an ink nozzle plate 21p in which ink nozzle holes Hk (FIG. 1) for ejecting ink are opened. The ink head 21 has an ink nozzle surface 21s, which is one surface of the ink nozzle plate 21p. In addition, the treatment liquid head 22 has a treatment liquid nozzle plate 22p in which treatment liquid nozzle holes Hs for ejecting the treatment liquid are opened. The treatment liquid head 22 has a treatment liquid nozzle surface 22s, which is one surface of the treatment liquid nozzle plate 22p.

[0017] The white ink and color inks are, for example, aqueous inks, and contain resin particles, coloring materials, organic solvents, surfactants, and water. In this embodiment, the white ink and color inks contain solids, including resin particles and solid coloring materials. For example, the resin particles are contained in the white ink and color inks at a concentration of 0.1 wt% to 30 wt%, and the solid coloring materials are contained at a concentration of 0.1 wt% to 20 wt%. The viscosity of the white ink and color inks is higher than that of the cleaning solution described below. The resin particles may contain, for example, at least one of methacrylic acid and acrylic acid as a monomer, and commercially available products may be used. The resin particles may further contain, for example, styrene, vinyl chloride, or the like as a monomer. The resin particles may be contained in an emulsion, for example. The average particle diameter of the resin particles is, for example, 30 nm to 200 nm.

[0018] The pretreatment liquid is a solution, such as an aqueous solution containing a polyvalent metal salt, that is used for pretreatment before printing and is suited to the type of ink, such as white ink, and the type of print medium W. The posttreatment liquid is a solution, such as an aqueous solution containing a resin, that is suited to the type of ink, such as color ink, and the type of print medium W, and is used for posttreatment after printing.

[0019] The platen 11 has a flat upper surface and defines the distance between the print medium W placed on the upper surface and the lower surfaces of the ink head 21 and treatment liquid head 22 provided opposite the print medium W. The tanks 12 are connected to the ink head 21 and treatment liquid head 22 by tubes 13. The tanks 12 include a plurality of first tanks 12a and a plurality of second tanks 12b. Some of the first tanks 12a store white ink, while the remaining first tanks 12a store ink of each color included in the color inks. Some of the second tanks 12b store pre-treatment liquid, while the remaining second tanks 12b store post-treatment liquid. The tanks 12 may store special color inks, such as red ink, green ink, and blue ink, which are different colors from the white ink and color inks. Separate ink heads may be provided to eject the special color inks.

[0020] The transport device 30 has, for example, two sets of transport rollers 31 and a transport motor M1. The two sets of transport rollers 31 are arranged with the platen 11 sandwiched between them in the transport direction Df. Each set of transport rollers 31 is configured as a roller pair and is arranged so that the print medium W is sandwiched between one roller and the other roller of the roller pair. One roller of each set of transport rollers 31 is connected to the transport motor M1. The transport rollers 31 are rotated by the rotational operation of the transport motor M1, thereby transporting the print medium W on the platen 11 in the transport direction Df.

[0021] The scanning device 40 includes a carriage 41, two guide rails 42, a scanning motor M2, and an endless belt 44. The two guide rails 42 extend above the platen 11 in the movement direction Ds, sandwiching the white ink head 21w and the pretreatment liquid head 22b in the transport direction Df. As shown in FIG. 1 , the carriage 41 supports the white ink head 21w and the pretreatment liquid head 22b, and is supported by the two guide rails 42 so as to be movable in the movement direction Ds. The endless belt 44 extends in the movement direction Ds, is connected to the carriage 41, and is attached to the scanning motor M2 via a pulley 45. When the scanning motor M2 rotates, the endless belt 44 operates, and accordingly, the carriage 41 moves back and forth along the guide rails 42 in the movement direction Ds. As a result, the white ink head 21w and the pretreatment liquid head 22b are moved back and forth by the carriage 41 in the movement direction Ds. When the color ink head 21c and the post-treatment liquid head 22a are provided separately, the carriage 41 supports the color ink head 21c and the post-treatment liquid head 22a in addition to the white ink head 21w and the pre-treatment liquid head 22b.

[0022] The treatment liquid cap 46 covers the treatment liquid nozzle surface 22s of the treatment liquid head 22. The ink cap 47 covers the ink nozzle surface 21s of the ink head 21. In other words, the treatment liquid cap 46 covers the treatment liquid nozzle surface 22s, which is one surface of the treatment liquid nozzle plate 22p. In addition, the ink cap 47 covers the ink nozzle surface 21s, which is one surface of the ink nozzle plate 21p. The coating process of the treatment liquid cap 46 and the ink cap 47 will be described later.

[0023] 2, the liquid ejection device 100 includes a control device 50, an interface 53, a head drive circuit DC1, a transport drive circuit DC2, a scan drive circuit DC3, a cap lift drive circuit DC4, a flow path switching drive circuit DC5, and a pump drive circuit DC6. The liquid ejection device 100 also includes lifting devices 32 and 33, a flow path switching mechanism 60, and a suction-type pump Pm. In this embodiment, the lifting device 32 corresponds to a first switching mechanism, and the lifting device 33 corresponds to a second switching mechanism.

[0024] The control device 50 corresponds to a computer, and has a calculation unit 51 and a storage unit 52. The control device 50 may be configured as a single device, or may be configured as a plurality of devices arranged in a distributed manner that cooperate to perform the operation of the liquid ejection device 100.

[0025] The calculation unit 51 includes at least one circuit, such as a processor such as a CPU and an integrated circuit such as an ASIC. The calculation unit 51 controls each unit by executing a predetermined program, and performs various operations such as liquid ejection.

[0026] The storage unit 52 is a memory accessible from the calculation unit 51 and includes RAM and ROM. The RAM temporarily stores various data, such as image data received from an external device and data converted by the calculation unit 51. The ROM stores printing programs and predetermined data for performing various data processing. The programs may be stored in an external storage medium, such as a CD-ROM, that is different from the storage unit 52 and accessible from the calculation unit 51. The programs stored in the recording medium may be read via a reading device and executed by the calculation unit 51.

[0027] The interface 53 receives various data such as image data from external devices such as a computer, a camera, a communication network, a display, a printer, etc. The image data is raster data that indicates an image to be printed on the print medium W, and includes information on printing conditions such as the type of print medium W.

[0028] The ink head 21 has a driving element 25. The treatment liquid head 22 has a driving element 26. The driving element 25 is a piezoelectric element, a heating element, an electrostatic actuator, or the like, and is provided corresponding to the ink nozzle holes Hk, and applies pressure to the ink to cause the ink to be ejected from the ink nozzle holes Hk. The driving element 26 is a piezoelectric element, a heating element, an electrostatic actuator, or the like, and is provided corresponding to the treatment liquid nozzle holes Hs, and applies pressure to the treatment liquid to cause the treatment liquid to be ejected from the treatment liquid nozzle holes Hs.

[0029] The head drive circuit DC1 controls the operation of the drive elements 25, 26 based on instructions from the control device 50. The drive element 25 imparts a predetermined ejection energy to the ink in the ink head 21, thereby ejecting the ink. The drive element 26 also imparts a predetermined ejection energy to the treatment liquid in the treatment liquid head 22, thereby ejecting the treatment liquid.

[0030] The transport drive circuit DC2 controls the operation of the transport motor M1 of the transport device 30 based on instructions from the control device 50. When the transport motor M1 is operated, the platen 11 transports the print medium W intermittently or continuously along the transport direction Df, and stops the print medium W at a predetermined position in the transport direction Df.

[0031] The scan drive circuit DC3 controls the operation of the scan motor M2 of the scanning device 40 based on instructions from the control device 50. When the scan motor M2 is operated, the carriage 41 moves back and forth in the movement direction Ds, causing the white ink head 21w and the pretreatment liquid head 22b to move back and forth in the movement direction Ds.

[0032] The lifting device 32 has a lifting motor M3. The lifting motor M3 is connected to the treatment liquid cap 46 via a drive mechanism including a ball screw, a rack and pinion, or the like (not shown). A cap lifting drive circuit DC4 controls the operation of the lifting motor M3 of the lifting device 32 based on instructions from the control device 50. The operation of the lifting motor M3 lifts and lowers the treatment liquid cap 46. When the treatment liquid head 22 is the pre-treatment liquid head 22b, the lifting device 32 lifts and lowers the treatment liquid cap 46, thereby switching between a first capped state Sc1 shown in FIG. 3A in which the treatment liquid nozzle surface 22s of the pre-treatment liquid head 22b is covered by the treatment liquid cap 46 and a first uncapped state Sa1 shown in FIG. 3B in which the treatment liquid nozzle surface 22s is not covered by the treatment liquid cap 46. In addition, when the processing liquid head 22 is a post-processing liquid head 22a, the lifting device 32 switches between a third capped state Sc3 of Figure 3A in which the processing liquid nozzle surface 22s of the post-processing liquid head 22a is covered by the processing liquid cap 46, and a third uncapped state Sa3 of Figure 3B in which the processing liquid nozzle surface 22s is not covered by the processing liquid cap 46.

[0033] The elevator device 33 also has an elevator motor M4. The elevator motor M4 is connected to the ink cap 47 via a drive mechanism including a ball screw or rack and pinion (not shown). A cap elevator drive circuit DC4 controls the operation of the elevator motor M4 of the elevator device 33 based on instructions from the control device 50. The ink cap 47 is raised and lowered by operation of the elevator motor M4. When the ink head 21 is a white ink head 21w, the elevator device 33 raises and lowers the ink cap 47 to switch between a second capped state Sc2 in which the ink nozzle surface 21s of the white ink head 21w is covered by the ink cap 47, and a second uncapped state Sa2 in which the ink nozzle surface 21s is not covered by the ink cap 47. If the ink head 21 is a color ink head 21c, the elevator device 33 switches between a fourth capped state Sc4 shown in FIG. 3A in which the ink nozzle surface 21s of the color ink head 21c is covered by the ink cap 47, and a fourth uncapped state Sa4 shown in FIG. 3B in which the ink nozzle surface 21s is not covered by the ink cap 47. In this embodiment, the treatment liquid cap 46 and the ink cap 47 are raised and lowered by different elevator devices 32 and 33, but this is not limiting and they may be raised and lowered by a common elevator device. In this case, the treatment liquid cap 46 and the ink cap 47 are brought into the capped state or the uncapped state at the same time.

[0034] The flow path switching drive circuit DC5 controls the operation of a switching motor M5 provided in the flow path switching mechanism 60 based on instructions from the control device 50. The flow path switching drive circuit DC5 also controls the opening and closing operation of an on-off valve Va provided in the flow path switching mechanism 60 based on instructions from the control device 50. The pump drive circuit DC6 controls the operation of a pump motor M6 provided in the pump Pm based on instructions from the control device 50. Details of the flow path switching mechanism 60 and the pump Pm will be described later.

[0035] The control device 50 acquires image data and executes a printing operation, which is a liquid ejection operation, based on the image data. The control device 50 ejects ink from the ink head 21 onto the print medium W while moving the ink head 21 in the movement direction Ds in the printing pass. The control device 50 then transports the print medium W forward in the transport direction Df. In this manner, the printing pass and the transport operation are repeated alternately. As a result, an image based on the image data is printed on the print medium W.

[0036] Next, Fig. 4 is a perspective view showing the configuration of the switching valve 60a. Fig. 5A shows the first waste liquid flow path P1 when the pretreatment liquid head 22b is purged, Fig. 5B shows the first cleaning liquid supply flow path P4 when the pretreatment liquid head 22b is cleaned, and Fig. 5C shows the suction flow path P8 when the pretreatment liquid head 22b is performing idle suction.

[0037] Fig. 6A shows the second waste liquid flow path P2 when the white ink head 21w is purged, Fig. 6B shows the second cleaning liquid supply flow path P6 when the white ink head 21w is cleaned, and Fig. 6C shows the suction flow path P9 when the white ink head 21w is subjected to idle suction. Fig. 7A shows the cleaning liquid bypass flow path Pb when the switching valve 60a is cleaned, and Fig. 7B shows the suction flow path of the cleaning liquid bypass flow path Pb when the switching valve 60a is cleaned.

[0038] 5A and other figures, the liquid ejection device 100 of this embodiment includes the above-mentioned flow path switching mechanism 60, a cleaning liquid tank 63, a waste liquid tank 64, a first waste liquid flow path P1, a first cleaning liquid supply flow path P4, a suction flow path P8, a second waste liquid flow path P2, a second cleaning liquid supply flow path P6, a suction flow path P9, and a cleaning liquid bypass flow path Pb. The flow path switching mechanism 60 includes a switching valve 60a, on-off valves Va1, Va2, and Va3, and the above-mentioned switching motor M5. In this embodiment, the first waste liquid flow path P1, the second waste liquid flow path P2, the first cleaning liquid supply flow path P4, the second cleaning liquid supply flow path P6, and the cleaning liquid bypass flow path Pb correspond to multiple flow paths.

[0039] 4, the flow path switching mechanism 60 includes a switching valve 60a having an outlet port Po and a plurality of inlet ports Pe. The flow path switching mechanism 60 switches the flow path connected to the outlet port Po among the plurality of flow paths.

[0040] The switching valve 60a has, for example, a cylindrical rotating member 61 with a bottom and a cylindrical fixed member 62 with a bottom. The rotating member 61 is inserted into the fixed member 62 coaxially. For ease of understanding, FIG. 4 shows the rotating member 61 separated from the fixed member 62. A slit 61s extending in the axial direction is provided in the peripheral side wall of the rotating member 61. A slit 61c extending in the radial direction is provided in the bottom of the rotating member 61. The slit 61s and the slit 61c are connected. The rotating member 61 is connected to a switching motor M5.

[0041] The outlet port Po and the plurality of inlet ports Pe described above are provided in the fixed member 62. The plurality of inlet ports Pe include a first inlet port Pe1, a second inlet port Pe2, and a third inlet port Pe3. The first inlet port Pe1, the second inlet port Pe2, and the third inlet port Pe3 are provided on the circumferential side wall of the fixed member 62. The first inlet port Pe1, the second inlet port Pe2, and the third inlet port Pe3 are arranged at predetermined intervals in the circumferential direction of the fixed member 62. Meanwhile, the outlet port Po is provided in the bottom part of the fixed member 62.

[0042] In the above configuration, when the switching motor M5 is operated, the rotating member 61 rotates around the rotation axis relative to the fixed member 62. The rotating member 61 rotates by a predetermined rotation angle, and the slit 61s of the rotating member 61 is connected to any one of the inlet ports Pe from the first inlet port Pe1, the second inlet port Pe2, and the third inlet port Pe3. As a result, the connected inlet port Pe is connected to the outlet port Po via the slit 61s and the slit 61c. As a result, the cleaning liquid and the like flowing into the switching valve 60a from the inlet port Pe flows out from the outlet port Po, as will be described later.

[0043] The cleaning liquid tank 63 stores cleaning liquid for cleaning the treatment liquid nozzle surface 22s and the ink nozzle surface 21s. In this embodiment, the cleaning liquid does not contain solids. The cleaning liquid is a liquid that can clean (dilute) ink, and contains, for example, an organic solvent, a surfactant, and a water-soluble solvent including water. The waste liquid tank 64 stores the discharged ink and cleaning liquid. In addition, the pump Pm is provided between the switching valve 60a and the waste liquid tank 64, and is connected to the outlet port Po of the switching valve 60a.

[0044] 5A, the first waste liquid flow path P1 connects the pre-treatment liquid head 22b, which is an example of the treatment liquid head 22, to the switching valve 60a, and passes the treatment liquid discharged into the treatment liquid cap 46. In detail, one end of the first waste liquid flow path P1 is connected to the treatment liquid cap 46, and the other end of the first waste liquid flow path P1 is connected to the first inlet port Pe1 of the switching valve 60a.

[0045] 6A, the second waste liquid flow path P2 connects the white ink head 21w, which is an example of the ink head 21, to the switching valve 60a and passes ink discharged into the ink cap 47. In detail, one end of the second waste liquid flow path P2 is connected to the ink cap 47, and the other end of the second waste liquid flow path P2 is connected to the second inlet port Pe2 of the switching valve 60a.

[0046] 5B, the first cleaning liquid supply flow path P4 connects the cleaning liquid tank 63 to the switching valve 60a via the processing liquid cap 46, and passes the cleaning liquid in the cleaning liquid tank 63. In detail, the first cleaning liquid supply flow path P4 is made up of the supply flow path P3 and the above-mentioned first waste liquid flow path P1. One end of the supply flow path P3 is connected to the cleaning liquid tank 63, and the other end of the supply flow path P3 is connected to the processing liquid cap 46. An on-off valve Va2 is provided in the supply flow path P3. The supply flow path P3 is opened or closed by opening or closing the on-off valve Va2.

[0047] As shown in FIG. 6B, the second cleaning liquid supply flow path P6 connects the cleaning liquid tank 63 to the switching valve 60a via the ink cap 47, and passes the cleaning liquid in the cleaning liquid tank 63 through it. In detail, the second cleaning liquid supply flow path P6 is made up of a part of the supply flow path P3, the supply flow path P5, and the second waste liquid flow path P2. One end of the supply flow path P5 is connected to a part of the supply flow path P3 between the on-off valve Va2 and the cleaning liquid tank 63, and the other end of the supply flow path P5 is connected to the ink cap 47. An on-off valve Va3 is provided in the supply flow path P5. The supply flow path P5 is opened or closed by opening or closing the on-off valve Va3.

[0048] As shown in FIG. 5C, the suction flow path P8 is composed of an atmosphere-communicating flow path P7, a portion of the supply flow path P3, and the first waste liquid flow path P1. One end of the atmosphere-communicating flow path P7 is connected to the atmosphere, and the other end of the atmosphere-communicating flow path P7 is connected to a portion of the supply flow path P3 upstream of the on-off valve Va2. In this configuration, the suction flow path P8 connects the atmosphere-communicating flow path P7 to the switching valve 60a via the treatment liquid cap 46 to pass air. An on-off valve Va1 is provided in the atmosphere-communicating flow path P7. The on-off valve Va1 opens or closes the atmosphere-communicating flow path P7.

[0049] 6C, the suction flow path P9 is made up of the above-mentioned atmosphere-communicating flow path P7, a part of the above-mentioned supply flow path P3, the above-mentioned supply flow path P5, and the above-mentioned second waste liquid flow path P2. In this configuration, the suction flow path P9 connects the atmosphere-communicating flow path P7, which is an atmosphere-communicating passage, to the switching valve 60a via the ink cap 47 to pass air.

[0050] As shown in FIG. 7A, the cleaning liquid bypass flow path Pb connects the cleaning liquid tank 63 to the switching valve 60a and passes the cleaning liquid therethrough without passing through the treatment liquid cap 46 and the ink cap 47. Specifically, the cleaning liquid bypass flow path Pb is configured by a part of the supply flow path P3 and a supply flow path P10. One end of the supply flow path P10 is connected to a part of the supply flow path P3 that is upstream of the on-off valve Va2, and the other end of the supply flow path P10 is connected to the third inlet port Pe3 of the switching valve 60a. As described above, the other end of the atmosphere-communicating flow path P7 is connected to a part of the supply flow path P3 that is upstream of the on-off valve Va2. Therefore, as shown in FIG. 7B, the atmosphere-communicating flow path P7 is connected to the cleaning liquid bypass flow path Pb, and air is supplied to the switching valve 60a via the cleaning liquid bypass flow path Pb.

[0051] 5 to 7, the processes performed by the control device 50 will be described in order. First, the process related to the pre-treatment liquid head 22b will be described. As shown in FIG. 5A, the control device 50 performs a first coating process in which the lifting device 32 covers the treatment liquid nozzle surface 22s of the pre-treatment liquid head 22b with the treatment liquid cap 46. Then, the control device 50 operates the pump Pm to perform a treatment liquid purging process in which the pre-treatment liquid is sucked through the treatment liquid nozzle holes Hs of the pre-treatment liquid head 22b and discharged into the treatment liquid cap 46. As a result, the pre-treatment liquid is stored in the treatment liquid cap 46.

[0052] Next, the control device 50 rotates the rotating member 61 of the switching valve 60a using the switching motor M5 so that the slit 61s of the rotating member 61 is connected to the first inlet port Pe1. As a result, the first waste liquid flow path P1 is connected to the outlet port Po, and is connected to the pump Pm via the outlet port Po. In this manner, the control device 50 operates the pump Pm while connecting the first waste liquid flow path P1 to the outlet port Po using the switching valve 60a of the flow path switching mechanism 60, thereby performing a first waste liquid process in which the pretreatment liquid discharged into the treatment liquid cap 46 is discharged from the treatment liquid cap 46 via the first waste liquid flow path P1, as shown in FIG. 5A . In this case, the pretreatment liquid in the treatment liquid cap 46 is discharged to the waste liquid tank 64 via the first waste liquid flow path P1.

[0053] 5B, the control device 50 connects the first cleaning liquid supply flow path P4 to the outlet port Po using the switching valve 60a of the flow path switching mechanism 60. In this case, the control device 50 rotates the rotating member 61 so that the slit 61s of the rotating member 61 is connected to the first inlet port Pe1, as described above, closes the on-off valve Va1, and opens the on-off valve Va2. Then, the control device 50 operates the pump Pm to perform a first cleaning process in which the cleaning liquid in the cleaning liquid tank 63 is supplied to the processing liquid cap 46 through the supply flow path P3. As a result, the cleaning liquid supplied to the processing liquid cap 46 comes into contact with the processing liquid nozzle surface 22s of the pre-processing liquid head 22b. Thereafter, the cleaning liquid in the processing liquid cap 46 is discharged to the waste liquid tank 64 through the first waste liquid flow path P1 by operating the pump Pm.

[0054] Next, with the first waste liquid flow path P1 connected to the outlet port Po and the on-off valve Va2 open as described above, the control device 50 opens the on-off valve Va1 as shown in FIG. 5C . This connects the suction flow path P8 to the outlet port Po. The control device 50 then operates the pump Pm to supply air to the suction flow path P8, the treatment liquid cap 46, and the switching valve 60a. This allows the pretreatment liquid and cleaning liquid remaining in the suction flow path P8, the treatment liquid cap 46, and the switching valve 60a to be discharged into the waste liquid tank 64. As described above, the first cleaning process is performed after the treatment liquid purging process and after the first waste liquid process. However, this is not limiting. The first cleaning process may be performed between the treatment liquid purging process and the first waste liquid process. This allows the cleaning liquid from the first cleaning process (i.e., the cleaning liquid in the treatment liquid cap 46) to be discharged into the waste liquid tank 64 via the first waste liquid flow path P1 together with the pretreatment liquid from the first waste liquid process (i.e., the pretreatment liquid in the treatment liquid cap 46).

[0055] Here, the control device 50 executes a determination process to determine whether or not to execute the first cleaning process based on the number of times the processing liquid purging process and the first waste liquid process have been executed. In this case, the control device 50 may compare the number of times the processing liquid purging process and the first waste liquid process have been executed with a threshold value, and execute the first cleaning process if the number of times is equal to or greater than the threshold value.

[0056] Next, the process related to the white ink head 21w will be described. As shown in Figure 6A, the control device 50 performs a second covering process in which the elevator device 33 covers the ink nozzle surface 21s of the white ink head 21w with the ink cap 47. The control device 50 then operates the pump Pm to perform an ink purging process in which white ink is sucked from the ink nozzle holes Hk of the white ink head 21w and discharged into the ink cap 47. This causes the ink to accumulate in the ink cap 47.

[0057] Next, the control device 50 rotates the rotating member 61 of the switching valve 60a using the switching motor M5 so that the slit 61s of the rotating member 61 is connected to the second inlet port Pe2. As a result, the second waste liquid flow path P2 is connected to the outlet port Po, and is connected to the pump Pm via the outlet port Po. In this manner, the control device 50 operates the pump Pm while connecting the second waste liquid flow path P2 to the outlet port Po using the switching valve 60a of the flow path switching mechanism 60, thereby performing a second waste liquid process in which the ink discharged into the ink cap 47 is discharged from the ink cap 47 via the second waste liquid flow path P2, as shown in FIG. 6A. In this case, the ink in the ink cap 47 is discharged to the waste liquid tank 64 via the second waste liquid flow path P2.

[0058] Next, as shown in FIG. 6B , the control device 50 connects the second cleaning liquid supply flow path P6 to the outlet port Po using the switching valve 60a of the flow path switching mechanism 60. In this case, the control device 50 rotates the rotating member 61 so that the slit 61s of the rotating member 61 connects to the second inlet port Pe2, closes the on-off valve Va1, and opens the on-off valve Va3. Then, the control device 50 operates the pump Pm to perform a second cleaning process, supplying cleaning liquid from the cleaning liquid tank 63 to the ink cap 47. In this case, the cleaning liquid from the cleaning liquid tank 63 is supplied to the ink cap 47 through the supply flow paths P3 and P5, which are part of the second cleaning liquid supply flow path P6. As a result, the cleaning liquid supplied to the ink cap 47 comes into contact with the ink nozzle surface 21s of the white ink head 21w. The cleaning liquid from the ink cap 47 is then discharged to the waste liquid tank 64 via the second waste liquid flow path P2 by operating the pump Pm.

[0059] Next, with the second waste liquid flow path P2 connected to the outlet port Po and the on-off valve Va3 open as described above, the control device 50 opens the on-off valve Va1 as shown in FIG. 6C. This connects the suction flow path P9 to the outlet port Po. The control device 50 then operates the pump Pm to supply air to the suction flow path P9, the ink cap 47, and the switching valve 60a. This allows the ink and cleaning liquid remaining in the suction flow path P9, the ink cap 47, and the switching valve 60a to be discharged into the waste liquid tank 64.

[0060] Here, the control device 50 executes a determination process to determine whether or not to execute the second cleaning process based on the number of times the processing liquid purging process and the second waste liquid process have been executed. In this case, the control device 50 may compare the number of times the processing liquid purging process and the second waste liquid process have been executed with a threshold value, and execute the second cleaning process if the number of times is equal to or greater than the threshold value.

[0061] Next, the process related to the cleaning liquid bypass flow path Pb will be described. As shown in FIG. 7A, the control device 50 connects the supply flow path P10 of the cleaning liquid bypass flow path Pb to the outlet port Po using the switching valve 60a of the flow path switching mechanism 60. In this case, the control device 50 rotates the rotating member 61 so that the slit 61s of the rotating member 61 is connected to the third inlet port Pe3, and closes the on-off valve Va1. The control device 50 then operates the pump Pm to supply the cleaning liquid in the cleaning liquid tank 63 to the switching valve 60a through the cleaning liquid bypass flow path Pb without passing through the treatment liquid cap 46 and the ink cap 47. The cleaning liquid supplied to the switching valve 60a is discharged into the waste liquid tank 64.

[0062] Next, with the supply flow path P10 of the cleaning liquid bypass flow path Pb connected to the outlet port Po as described above, the control device 50 opens the on-off valve Va1 as shown in FIG. 7B. This connects the atmosphere communication flow path P7 to the outlet port Po via the cleaning liquid bypass flow path Pb. The control device 50 then operates the pump Pm to supply air to the cleaning liquid bypass flow path Pb and the switching valve 60a. This allows the cleaning liquid remaining in the cleaning liquid bypass flow path Pb and the switching valve 60a to be discharged into the waste liquid tank 64.

[0063] Here, the processing related to the pre-treatment liquid head 22b has been described above, but the processing related to the post-treatment liquid head 22a can also be performed in the same manner as the processing related to the pre-treatment liquid head 22b.

[0064] The control device 50 performs a third covering process in which the lifting device 32 covers the processing liquid nozzle surface 22s of the post-processing liquid head 22a with the processing liquid cap 46. Then, the control device 50 operates the pump Pm to perform a processing liquid purging process in which the post-processing liquid is sucked from the processing liquid nozzle holes Hs of the post-processing liquid head 22a and discharged into the processing liquid cap 46. As a result, the post-processing liquid is stored in the processing liquid cap 46.

[0065] Next, the control device 50 connects the first waste liquid flow path P1 to the outlet port Po using the switching valve 60a of the flow path switching mechanism 60 in the same manner as above, and operates the pump Pm to perform a third waste liquid process in which the post-treatment liquid discharged into the treatment liquid cap 46 is discharged from the treatment liquid cap 46 via the first waste liquid flow path P1. In this case, the post-treatment liquid in the treatment liquid cap 46 is discharged into the waste liquid tank 64 via the first waste liquid flow path P1.

[0066] Next, the control device 50 connects the first cleaning liquid supply flow path P4 to the outlet port Po using the switching valve 60a of the flow path switching mechanism 60. In this case, the control device 50 connects the first cleaning liquid supply flow path P4 to the outlet port Po via the first inlet port Pe1 by rotating the rotating member 61 so that the slit 61s of the rotating member 61 is connected to the first inlet port Pe1 as described above, closes the on-off valve Va1, and opens the on-off valve Va2. Then, the control device 50 operates the pump Pm to perform a third cleaning process in which the cleaning liquid in the cleaning liquid tank 63 is supplied to the processing liquid cap 46 through the supply flow path P3. As a result, the cleaning liquid supplied to the processing liquid cap 46 comes into contact with the processing liquid nozzle surface 22s of the post-processing liquid head 22a. Thereafter, the cleaning liquid in the processing liquid cap 46 is discharged to the waste liquid tank 64 through the first waste liquid flow path P1 by operating the pump Pm.

[0067] Next, with the first waste liquid flow path P1 connected to the outlet port Po and the on-off valve Va2 open as described above, the control device 50 opens the on-off valve Va1. This connects the suction flow path P8 to the outlet port Po. The control device 50 then operates the pump Pm to supply air to the suction flow path P8, the processing liquid cap 46, and the switching valve 60a. This causes the post-processing liquid and cleaning liquid remaining in the suction flow path P8, the processing liquid cap 46, and the switching valve 60a to be discharged into the waste liquid tank 64.

[0068] The control device 50 also performs a determination process for the post-treatment liquid head 22a, similar to the pre-treatment liquid head 22b, to determine whether or not to perform the third cleaning process based on the number of times the processing liquid purging process and the third waste liquid process have been performed. In this case, the control device 50 may compare the number of times the processing liquid purging process and the third waste liquid process have been performed with a threshold, and perform the third cleaning process if the number of times is equal to or greater than the threshold.

[0069] Fig. 8 is a flowchart showing the flow of maintenance processing for the pre-treatment liquid head 22b and the white ink head 21w. Fig. 9 is a flowchart showing the flow of maintenance processing for the color ink heads c and the post-treatment liquid head 22a. Note that in the examples of Fig. 8 and Fig. 9, the treatment liquid cap 46 and the ink cap 47 are described as being raised and lowered by a common lifting device.

[0070] 8, the control device 50 first performs a first coating process to cover the treatment liquid nozzle surface 22s of the pretreatment liquid head 22b with the treatment liquid cap 46, and then performs a second coating process to cover the ink nozzle surface 21s of the white ink head 21w with the ink cap 47 at the same time as the first coating process (step S1). Next, the control device 50 performs a treatment liquid purging process to suck the pretreatment liquid from the treatment liquid nozzle holes Hs of the pretreatment liquid head 22b and discharge it into the treatment liquid cap 46 (step S2). After the treatment liquid purging process, the pretreatment liquid in the treatment liquid cap 46 is discharged into the waste liquid tank 64.

[0071] Next, the control device 50 executes a first cleaning process in which the cleaning liquid in the cleaning liquid tank 63 is supplied to the processing liquid cap 46 (step S3). The first cleaning process cleans the processing liquid nozzle surface 22s of the processing liquid head 22b. Then, the control device 50 supplies air to the suction flow path P8, the processing liquid cap 46, and the switching valve 60a (step S4). As a result, the processing liquid and cleaning liquid remaining in the switching valve 60a and the like are discharged into the waste liquid tank 64.

[0072] Next, the control device 50 performs an ink purge process, which sucks white ink from the ink nozzle holes Hk of the white ink head 21w and discharges it into the ink cap 47 (step S5). After the ink purge process, the white ink in the ink cap 47 is discharged into the waste liquid tank 64. The control device 50 may also perform a preliminary cleaning process, which is a process performed before the ink purge process. In this case, the control device 50 operates the pump Pm to supply cleaning liquid from the cleaning liquid tank 63 to the ink cap 47 via the second cleaning liquid supply flow path P6, and then discharges the cleaning liquid supplied to the ink cap 47 via the second cleaning liquid supply flow path P6 from the ink cap 47 via the second waste liquid flow path P2. This allows the ink cap 47, the second waste liquid flow path P2, and the switching valve 60a, through which white ink or color ink flows during the ink purge process, to be wetted with cleaning liquid in advance. In such a preliminary cleaning process, the suction force of the pump Pm may be weaker than the suction force of the pump Pm during the ink purge process. In this case, the control device 50 sets the rotation speed of the pump motor M6 of the pump Pm in the preliminary cleaning process to be lower than the rotation speed of the pump motor M6 of the pump Pm in the ink purging process, thereby allowing droplets of cleaning liquid to remain in the second waste liquid flow path P2 and the switching valve 60a in advance.

[0073] The control device 50 then executes a second cleaning process, supplying the cleaning liquid in the cleaning liquid tank 63 to the ink cap 47 (step S6). The second cleaning process cleans the ink nozzle surface 21s of the white ink head 21w. Next, the control device 50 supplies air to the suction flow path P9, the ink cap 47, and the switching valve 60a (step S7). This causes the white ink and cleaning liquid remaining in the switching valve 60a and other components to be discharged into the waste liquid tank 64.

[0074] Next, the control device 50 supplies the cleaning liquid in the cleaning liquid tank 63 to the switching valve 60a through the cleaning liquid bypass flow path Pb without passing through the treatment liquid cap 46 and the ink cap 47 (step S8). Then, the control device 50 supplies air to the cleaning liquid bypass flow path Pb and the switching valve 60a (step S9). The control device 50 releases the treatment liquid cap 46 from covering the treatment liquid nozzle surface 22s and the ink cap 47 from covering the ink nozzle surface 21s (step S10). Next, the control device 50 moves the pre-treatment liquid head 22b and the white ink head 21w to predetermined positions using the carriage 41, and performs a wiping process on the treatment liquid nozzle surface 22s and the ink nozzle surface 21s using wiper members (not shown) (step S11). Thereafter, the control device 50 moves the pretreatment liquid head 22b and the white ink head 21w using the carriage 41, covers the treatment liquid nozzle surface 22s with the treatment liquid cap 46, and covers the ink nozzle surface 21s with the ink cap 47 (step S12).

[0075] As shown in FIG. 9, the control device 50 first performs a third coating process to cover the processing liquid nozzle surface 22s of the post-processing liquid head 22a with the processing liquid cap 46, and then, at the same time as the third coating process, performs a second coating process to cover the ink nozzle surface 21s of the color ink head 21c with the ink cap 47 (step S21).

[0076] Next, the control device 50 performs an ink purge process, in which color ink is sucked from the ink nozzle holes Hk of the color ink head 21c and discharged into the ink cap 47 (step S22). After the ink purge process, the color ink in the ink cap 47 is discharged into the waste liquid tank 64. Then, the control device 50 performs a second cleaning process, in which cleaning liquid in the cleaning liquid tank 63 is supplied to the ink cap 47 (step S23). The ink nozzle surface 21s of the color ink head 21c is cleaned by the second cleaning process. Next, the control device 50 supplies air to the suction flow path P9, the ink cap 47, and the switching valve 60a (step S24). As a result, the color ink and cleaning liquid remaining in the switching valve 60a and the like are discharged into the waste liquid tank 64.

[0077] Next, the control device 50 executes a processing liquid purging process (step S25) in which the post-processing liquid is sucked from the processing liquid nozzle holes Hs of the post-processing liquid head 22a and discharged into the processing liquid cap 46. After the processing liquid purging process, the post-processing liquid in the processing liquid cap 46 is discharged into the waste liquid tank 64.

[0078] Next, the control device 50 executes a third cleaning process in which the cleaning liquid in the cleaning liquid tank 63 is supplied to the processing liquid cap 46 (step S26). The processing liquid nozzle surface 22s of the post-processing liquid head 22a is cleaned by the third cleaning process. Then, the control device 50 supplies air to the suction flow path P8, the processing liquid cap 46, and the switching valve 60a (step S27). As a result, the post-processing liquid and cleaning liquid remaining in the switching valve 60a, etc. are discharged into the waste liquid tank 64.

[0079] Next, the control device 50 supplies the cleaning liquid in the cleaning liquid tank 63 to the switching valve 60a through the cleaning liquid bypass flow path Pb without passing through the treatment liquid cap 46 and the ink cap 47 (step S28). Then, the control device 50 supplies air to the cleaning liquid bypass flow path Pb and the switching valve 60a (step S29). The control device 50 releases the treatment liquid cap 46 from covering the treatment liquid nozzle surface 22s and the ink cap 47 from covering the ink nozzle surface 21s (step S30). Next, the control device 50 moves the post-treatment liquid head 22a and the color ink head 21c to predetermined positions using the carriage 41, and performs a wiping process on the treatment liquid nozzle surface 22s and the ink nozzle surface 21s using wiper members (not shown) (step S31). Thereafter, the control device 50 moves the posttreatment liquid head 22a and the color ink head 21c using the carriage 41, covers the treatment liquid nozzle surface 22s with the treatment liquid cap 46, and covers the ink nozzle surface 21s with the ink cap 47 (step S32).

[0080] In the above, the carriage 41 supported the pre-treatment liquid head 22b and the white ink head 21w, but as will be described below, it may also support the color ink heads 21c and the post-treatment liquid head 22a. Figure 10 is a diagram showing an embodiment in which the carriage 41 supports the pre-treatment liquid head 22b, the white ink head 21w, the color ink heads 21c, and the post-treatment liquid head 22a. In the configuration in Figure 10, only the differences from the configuration in Figures 7A and 7B will be described.

[0081] As shown in FIG. 10 , in addition to the treatment liquid cap 46 covering the treatment liquid nozzle surface 22s1 of the pre-treatment liquid head 22b and the ink cap 47 covering the ink nozzle surface 21s1 of the white ink head 21w, a treatment liquid cap 146 and an ink cap 147 are provided. Furthermore, a supply flow path P11, a waste liquid flow path P12, a supply flow path P13, and a waste liquid flow path P14 are provided, and instead of the flow path switching mechanism 60 including the switching valve 60a shown in FIGS. 7A and 7B , a flow path switching mechanism 160 including a switching valve 160a having a rotating member 161 and a fixed member 162 is provided. The operation of the switching valve 160a is basically the same as that of the switching valve 60a. The switching valve 160a has an outlet port and five inlet ports. The rotating member 161 rotates at a predetermined rotation angle, and the slit of the rotating member 161 is connected to one of the first to fifth inlet ports. This connects one of the inlet ports to the outlet port.

[0082] The treatment liquid cap 146 covers the treatment liquid nozzle surface 22s2 of the post-treatment liquid head 22a, and the ink cap 147 covers the ink nozzle surface 21s2 of the color ink head 21c. One end of the supply flow path P11 is connected to a portion of the supply flow path P3 downstream of the on-off valve Va2, and the other end of the supply flow path P11 is connected to the ink cap 147. One end of the waste liquid flow path P12 is connected to the ink cap 147, and the other end of the waste liquid flow path P12 is connected to the fourth inlet port of the switching valve 160a. One end of the supply flow path P13 is connected to a portion of the supply flow path P5 downstream of the on-off valve Va3, and the other end of the supply flow path P13 is connected to the treatment liquid cap 146. One end of the waste liquid flow path P14 is connected to the treatment liquid cap 146, and the other end of the waste liquid flow path P14 is connected to the fifth inlet port of the switching valve 160a.

[0083] 10, similarly to the configuration in Fig. 7A, the control device 50 closes the on-off valve Va1 and operates the pump Pm to supply the cleaning liquid in the cleaning liquid tank 63 to the switching valve 160a through the cleaning liquid bypass flow path Pb without passing through the treatment liquid caps 46, 146 and the ink caps 47, 147. Thus, the switching valve 160a and the like can be cleaned with the cleaning liquid.

[0084] In the above description, the pre-treatment liquid head 22b and the white ink head 21w are provided separately and independently, but as will be described below, a treatment liquid nozzle surface for ejecting treatment liquid and an ink nozzle surface for ejecting ink may be provided in a single ejection head. Fig. 11A is a diagram showing an ejection head 120 and a treatment liquid cap 46 and an ink cap 47 corresponding to the ejection head 120, and Fig. 11B is a diagram showing the ejection head 120 and a cap 150 corresponding to the ejection head 120. Note that the cleaning process and other processes performed by the control device 50 in the configurations shown in Figs. 11A and 11B are basically the same as the cleaning process and other processes described above.

[0085] As shown in FIG. 11A, the ejection head 120 has a nozzle plate 120p in which are opened treatment liquid nozzle holes Hs for ejecting a treatment liquid containing either one of a pre-treatment liquid, a post-treatment liquid, or a pre-treatment liquid and a post-treatment liquid, and ink nozzle holes Hk for ejecting an ink containing either one of a white ink, a color ink, or a white ink and a color ink.

[0086] A treatment liquid nozzle surface 122s, which is one surface of the nozzle plate 120p and is a portion where the treatment liquid nozzle holes Hs are located, can be in a capped state Sc1 where it is covered by the treatment liquid cap 46, or in an uncapped state Sa1 where it is not covered by the treatment liquid cap 46. Furthermore, an ink nozzle surface 121s, which is one surface of the nozzle plate 120p and is a portion where the ink nozzle holes Hk are located, can be in a capped state Sc2 where it is covered by the ink cap 47, or in an uncapped state Sa2 where it is not covered by the ink cap 47.

[0087] As shown in FIG. 11B, the ejection head 120 has a nozzle plate 120p in which are opened treatment liquid nozzle holes Hs for ejecting a treatment liquid containing either one of a pre-treatment liquid, a post-treatment liquid, or a pre-treatment liquid and a post-treatment liquid, and ink nozzle holes Hk for ejecting an ink containing either one of a white ink, a color ink, or a white ink and a color ink.

[0088] The processing liquid nozzle surface 122s, which is one side of the nozzle plate 120p and is the part where the processing liquid nozzle holes Hs are located, and the ink nozzle surface 121s, which is one side of the nozzle plate 120p and is the part where the ink nozzle holes Hk are located, can be in a capped state Sc5 in which they are simultaneously covered by the cap 150, or in an uncapped state Sa5 in which they are not simultaneously covered by the cap 150.

[0089] As described above, according to the liquid ejection device 100 of this embodiment, the cleaning liquid bypass flow path Pb supplies the cleaning liquid in the cleaning liquid tank 63 to the switching valve 60a without passing through the treatment liquid cap 46 and the ink cap 47. The cleaning liquid supplied directly from the cleaning liquid tank 63 to the switching valve 60a in this manner makes it easier to dilute the white ink and color inks, as well as the pre-treatment liquid and post-treatment liquid, present in the switching valve 60a and the pump Pm connected to the switching valve 60a via a tube. This makes it possible to reduce solidification of the ink due to contact between the ink and the treatment liquid in the flow path including the switching valve 60a, etc.

[0090] In this embodiment, the atmosphere communication passage P7 is connected to the cleaning liquid bypass passage Pb, and air is supplied to the switching valve 60a via the cleaning liquid bypass passage Pb. This allows the cleaning liquid remaining in the cleaning liquid bypass passage Pb and the switching valve 60a to be discharged into the waste liquid tank 64.

[0091] In this embodiment, the white ink head 21w ejects white ink onto the area where the pretreatment liquid head 22b ejected the pretreatment liquid, thereby ensuring that the white ink is ejected reliably onto the area that has been pretreated with the pretreatment liquid, thereby improving the fixability of the white ink.

[0092] In this embodiment, the post-treatment liquid head 22a ejects the post-treatment liquid onto the area where the color ink head 21c ejected the color ink. This ensures that the post-treatment liquid is ejected reliably onto the area where the color ink has been ejected, thereby enabling the post-treatment of the color ink to be performed appropriately.

[0093] In this embodiment, the control device 50 performs a determination process to determine whether to perform the first cleaning process based on the number of times the processing liquid purging process and the first waste liquid process have been performed, thereby determining the timing to perform the first cleaning process appropriately.

[0094] In this embodiment, the control device 50 performs a determination process to determine whether or not to perform the second cleaning process based on the number of times the processing liquid purging process and the second waste liquid process have been performed, thereby determining the timing to perform the second cleaning process appropriately.

[0095] In this embodiment, the control device 50 also performs a determination process for the post-treatment liquid head 22a, similar to the pre-treatment liquid head 22b, to determine whether or not to perform the third cleaning process based on the number of times the processing liquid purge process and the third waste liquid process have been performed, thereby enabling the timing for performing the third cleaning process to be determined appropriately.

[0096] Furthermore, in this embodiment, the carriage 41 may support the color ink heads 21c and the post-treatment liquid head 22a in addition to the white ink head 21w and the pre-treatment liquid head 22b. In this case, various processes such as cleaning processes can be performed on the four heads using a common flow path switching mechanism 160.

[0097] In this embodiment, the ink contains solids, including resin particles and colorant solids. The resin particles are contained in the ink at a concentration of 0.1 wt% to 30 wt%, and the colorant solids are contained at a concentration of 0.1 wt% to 20 wt%. The cleaning liquid is a liquid containing no solids but other materials. Because ink requires a cleaning liquid to remove, it adheres strongly to the switching valve 60a and other components, impeding the operation of the switching valve 60a. In this embodiment, the cleaning liquid does not contain solids, so solids are less likely to remain inside the switching valve 60a after flowing, and are less likely to impede the operation of the switching valve 60a, compared to when the cleaning liquid contains solids. This reduces the viscosity of the ink with the cleaning liquid, preventing the operation of the switching valve 60a from being impeded.

[0098] In this embodiment, a pre-cleaning process may be performed before the ink purge process. This allows the ink cap 47, the second waste liquid flow path P2, and the switching valve 60a, which are targets through which white ink or color ink flows during the ink purge process, to be wetted with cleaning liquid in advance. Therefore, even when high-viscosity ink is used, the viscosity of the ink can be reduced by contacting the ink with the cleaning liquid in the pre-cleaning process, thereby suppressing or preventing the ink from solidifying in the switching valve 60a, etc.

[0099] In this embodiment, the suction force of the pump Pm in the preliminary cleaning process may be smaller than the suction force of the pump Pm in the ink purging process, in which case the power consumption of the pump motor M6 of the pump Pm in the preliminary cleaning process is reduced.

[0100] Furthermore, in this embodiment, the ejection head 120 may have a nozzle plate 120p in which the treatment liquid nozzle holes Hs and the ink nozzle holes Hk are opened. In this case, it is not necessary to separate the ink head and the treatment liquid head, and the structure is simplified.

[0101] Furthermore, in this embodiment, a single cap 150 may be applied to the ejection head 120 that has the treatment liquid nozzle surface 122s and the ink nozzle surface 121s. In this case, there is no need to separate the treatment liquid cap 46 and the ink cap 47, and the structure is simplified.

[0102] Although several other embodiments have been described above, the following modified examples may also be adopted without departing from the gist of the present disclosure.

[0103] In the above embodiment, an opening / closing valve may be separately provided in the supply passage P3 at a portion upstream of the joining portion with the atmosphere communication passage P7.

[0104] Furthermore, in the above embodiment, the ink head 21 that ejects white ink or color ink is given as an example, but this is not limited to this, and for example, an ink head that ejects clear ink or special color ink may also be applied.

[0105] Furthermore, in the above embodiment, the ink head 21 may eject only white ink, and the treatment liquid head 22 may eject only pretreatment liquid. In this case, the ink head 21 does not even have flow paths for color inks, and the treatment liquid head 22 does not even have flow paths for posttreatment liquid. In other words, the liquid ejection device 100 may be a dedicated printer that prints a white base on a printing medium by causing the ink head 21 to eject white ink after causing the treatment liquid head 22 to eject pretreatment liquid.

[0106] Furthermore, in the above embodiment, the ink head 21 is a serial head type, but it may also be a line head type. [Explanation of symbols]

[0107] 21 Ink head 21c color ink head 21p Ink nozzle plate 21s Ink nozzle surface 21w white ink head 22 Processing liquid head 22a Post-treatment liquid head 22b Pre-treatment liquid head 22p Processing liquid nozzle plate 22s Processing liquid nozzle surface 32,33 Lifting device 46,146 Processing liquid cap 47,147 Ink Caps 50 Control device 60,160 Flow path switching mechanism 60a,160a switching valve 63 Cleaning solution tank 100 Liquid dispensing device 120 Discharge Head 120p nozzle plate 121s Ink nozzle surface 122s Processing liquid nozzle surface 150 caps Hk ink nozzle hole Hs Processing liquid nozzle hole P1 First waste fluid flow path P2 Second waste fluid flow path P4 First cleaning liquid supply channel P6 Second cleaning liquid supply channel P7 Air communication channel Pb cleaning solution bypass flow path PE inlet port Pm Pump Po Outlet Port Sc1, Sc2, Sc3 cap states Sa1, Sa2, Sa3 Uncapped

Claims

1. a processing liquid head including a processing liquid nozzle plate having processing liquid nozzle holes for discharging a pre-processing liquid, a post-processing liquid, and a processing liquid containing any one of the pre-processing liquid and the post-processing liquid; an ink head having an ink nozzle plate in which ink nozzle holes are opened for ejecting white ink, color ink, and ink containing any one of the white ink and the color ink; a processing liquid cap for covering a processing liquid nozzle surface, which is one surface of the processing liquid nozzle plate; an ink cap that covers an ink nozzle surface, which is one surface of the ink nozzle plate; a cleaning liquid tank for storing a cleaning liquid; a plurality of flow paths; a flow path switching mechanism including a switching valve having an outlet port and a plurality of inlet ports, and switching a flow path to be communicated with the outlet port among the plurality of flow paths; The plurality of flow paths are a first waste liquid flow path that connects the processing liquid head and the switching valve and through which the processing liquid discharged into the processing liquid cap passes; a second waste liquid flow path that connects the ink head and the switching valve and passes the ink discharged into the ink cap; a first cleaning liquid supply flow path that connects the cleaning liquid tank to the switching valve via the processing liquid cap and allows the cleaning liquid to pass through; a second cleaning liquid supply flow path that connects the cleaning liquid tank to the switching valve via the ink cap and allows the cleaning liquid to pass through; a cleaning liquid bypass flow path that connects the cleaning liquid tank to the switching valve and passes the cleaning liquid without passing through the treatment liquid cap and the ink cap.

2. a pump connected to the outlet port of the switching valve; The liquid ejection device according to claim 1 , further comprising: an atmosphere communication channel connected to the cleaning liquid bypass channel, the atmosphere communication channel supplying air to the switching valve via the cleaning liquid bypass channel.

3. the treatment liquid head is a pretreatment liquid head that ejects the pretreatment liquid as the treatment liquid, the ink head is a white ink head that ejects the white ink as the ink, The liquid ejection device according to claim 1 , wherein the ink head ejects the white ink onto a portion onto which the treatment liquid head ejects the pretreatment liquid.

4. the ink head is a color ink head that ejects the color ink as the ink, the processing liquid head is a post-processing liquid head that ejects the post-processing liquid as the processing liquid, The liquid ejection device according to claim 1 , wherein the treatment liquid head ejects the post-treatment liquid onto a portion onto which the color ink has been ejected.

5. a first switching mechanism that switches between a first capped state in which the processing liquid nozzle surface is covered by the processing liquid cap and a first uncapped state in which the processing liquid nozzle surface is not covered by the processing liquid cap; a pump connected to the outlet port of the switching valve; a control device, The control device a first covering process of covering the processing liquid nozzle surface with the processing liquid cap by the first switching mechanism; a processing liquid purging process in which the pump is operated to discharge the pre-processing liquid from the processing liquid nozzle hole into the processing liquid cap; a first waste liquid processing step of connecting the first waste liquid flow path to the outlet port by the flow path switching mechanism and operating the pump to discharge the pretreatment liquid discharged into the treatment liquid cap from the treatment liquid cap through the first waste liquid flow path; a first cleaning process in which the first cleaning liquid supply flow path is connected to the outlet port by the flow path switching mechanism and the pump is operated to supply the cleaning liquid in the cleaning liquid tank to the processing liquid cap; The liquid ejection apparatus according to claim 1 , further comprising: a determination process for determining whether or not to execute the first cleaning process based on the number of times the processing liquid purging process and the first waste liquid process have been executed.

6. a second switching mechanism that switches between a second capped state in which the ink nozzle surface is covered by the ink cap and a second uncapped state in which the ink nozzle surface is not covered by the ink cap; a pump connected to the outlet port of the switching valve; a control device, The control device a second covering process of covering the ink nozzle surface with the ink cap by the second switching mechanism; an ink purging process in which the pump is operated to discharge the ink from the ink nozzle holes into the ink cap; a second waste liquid treatment in which the second waste liquid flow path is connected to the outlet port by the flow path switching mechanism and the pump is operated to discharge the ink discharged into the ink cap from the ink cap via the second waste liquid flow path; a second cleaning process in which the second cleaning liquid supply flow path is connected to the outlet port by the flow path switching mechanism and the pump is operated to supply the cleaning liquid in the cleaning liquid tank to the ink cap; The liquid ejection apparatus according to claim 1 , further comprising: a determination process for determining whether or not to execute the second cleaning process based on the number of times the ink purge process and the second waste liquid process have been executed.

7. a first switching mechanism that switches between a third capped state in which the processing liquid nozzle surface is covered by the processing liquid cap and a third uncapped state in which the processing liquid nozzle surface is not covered by the processing liquid cap; a pump connected to the outlet port of the switching valve; a control device, The control device a third covering process of covering the processing liquid nozzle surface with the processing liquid cap by the first switching mechanism; a processing liquid purging process in which the pump is operated to discharge the post-processing liquid from the processing liquid nozzle hole into the processing liquid cap; a third waste liquid treatment in which the first waste liquid flow path is connected to the outlet port by the flow path switching mechanism and the pump is operated to discharge the post-treatment liquid discharged into the treatment liquid cap from the treatment liquid cap through the first waste liquid flow path; a third cleaning process in which the first cleaning liquid supply flow path is connected to the outlet port by the flow path switching mechanism and the pump is operated to supply the cleaning liquid in the cleaning liquid tank to the processing liquid cap; The liquid ejection apparatus according to claim 1 , further comprising: a determination process for determining whether or not to execute the third cleaning process based on the number of times the processing liquid purging process and the third waste liquid process have been executed.

8. the treatment liquid head includes a pre-treatment liquid head that ejects the pre-treatment liquid and a post-treatment liquid head that ejects the post-treatment liquid, 2. The liquid ejection device according to claim 1, wherein the ink heads include a white ink head that ejects the white ink and color ink heads that eject the color inks.

9. the color ink contains solids, the solid content includes resin fine particles and solid content of a colorant, the resin fine particles are contained in the color ink in an amount of 0.1 wt % or more and 30 wt % or less, the solid content of the color material is contained in the color ink in a range of 0.1 wt % to 20 wt %; The liquid ejection device according to claim 6 , wherein the cleaning liquid does not contain the solid content.

10. The liquid ejection device described in claim 9, wherein the control device performs a preliminary cleaning process, which is a process performed before the ink purging process, by operating the pump to supply the cleaning liquid in the cleaning liquid tank to the ink cap via the second cleaning liquid supply flow path, and then discharging the cleaning liquid supplied to the ink cap via the second cleaning liquid supply flow path from the ink cap via the second waste liquid flow path.

11. the pump is a suction pump, The liquid ejection apparatus according to claim 10 , wherein the suction force of the pump during the preliminary cleaning process is smaller than the suction force of the pump during the ink purging process.

12. a first switching mechanism that switches between a first capped state in which the processing liquid nozzle surface is covered by the processing liquid cap and a first uncapped state in which the processing liquid nozzle surface is not covered by the processing liquid cap; a pump connected to the outlet port of the switching valve; a control device, The control device a first covering process of covering the processing liquid nozzle surface with the processing liquid cap by the first switching mechanism; a processing liquid purging process in which the pump is operated to discharge the pre-processing liquid from the processing liquid nozzle hole into the processing liquid cap; a first waste liquid processing step of connecting the first waste liquid flow path to the outlet port by the flow path switching mechanism and operating the pump to discharge the pretreatment liquid discharged into the treatment liquid cap from the treatment liquid cap through the first waste liquid flow path; a first cleaning process in which the first cleaning liquid supply flow path is connected to the outlet port by the flow path switching mechanism and the pump is operated to supply the cleaning liquid in the cleaning liquid tank to the processing liquid cap; The liquid ejection apparatus according to claim 1 , wherein the first cleaning process is performed between the processing liquid purging process and the first waste liquid process.

13. an ejection head having a nozzle plate in which treatment liquid nozzle holes for ejecting a pre-treatment liquid, a post-treatment liquid, and a treatment liquid containing any one of the pre-treatment liquid and the post-treatment liquid, and ink nozzle holes for ejecting a white ink, a color ink, and an ink containing any one of the white ink and the color ink are opened; a processing liquid cap that covers a processing liquid nozzle surface, which is one surface of the nozzle plate and is a portion where the processing liquid nozzle holes are located; an ink cap that covers an ink nozzle surface, which is one surface of the nozzle plate and is a portion where the ink nozzle holes are located; a cleaning liquid tank for storing a cleaning liquid; a plurality of flow paths; a flow path switching mechanism including a switching valve having an outlet port and a plurality of inlet ports, and switching a flow path to be communicated with the outlet port among the plurality of flow paths; The plurality of flow paths are a first waste liquid flow path that connects the ejection head and the switching valve and through which the treatment liquid discharged into the treatment liquid cap passes; a second waste liquid flow path that connects the ejection head and the switching valve and passes the ink discharged into the ink cap; a first cleaning liquid supply flow path that connects the cleaning liquid tank to the switching valve via the processing liquid cap and allows the cleaning liquid to pass through; a second cleaning liquid supply flow path that connects the cleaning liquid tank to the switching valve via the ink cap and allows the cleaning liquid to pass through; a cleaning liquid bypass flow path that connects the cleaning liquid tank to the switching valve and passes the cleaning liquid without passing through the treatment liquid cap and the ink cap.

14. an ejection head having a nozzle plate in which treatment liquid nozzle holes for ejecting a pre-treatment liquid, a post-treatment liquid, and a treatment liquid containing any one of the pre-treatment liquid and the post-treatment liquid, and ink nozzle holes for ejecting a white ink, a color ink, and an ink containing any one of the white ink and the color ink are opened; a cap that covers a treatment liquid nozzle surface, which is one surface of the nozzle plate and is a portion where the treatment liquid nozzle holes are located, and an ink nozzle surface, which is one surface of the nozzle plate and is a portion where the ink nozzle holes are located; a cleaning liquid tank for storing a cleaning liquid; a plurality of flow paths; a flow path switching mechanism including a switching valve having an outlet port and a plurality of inlet ports, and switching a flow path to be communicated with the outlet port among the plurality of flow paths; The plurality of flow paths are a first waste liquid flow path that connects the ejection head and the switching valve and through which the treatment liquid discharged into the cap passes; a second waste liquid flow path that connects the ejection head and the switching valve and through which the ink discharged into the cap passes; a first cleaning liquid supply flow path that connects the cleaning liquid tank to the switching valve via the cap and allows the cleaning liquid to pass through; a second cleaning liquid supply flow path that connects the cleaning liquid tank to the switching valve via the cap and allows the cleaning liquid to pass through; a cleaning liquid bypass flow path that connects the cleaning liquid tank to the switching valve without passing through the cap and allows the cleaning liquid to pass through.

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