Recording device and cleaning mechanism

Abstract

To provide a recording device and a cleaning mechanism which can appropriately discharge a cleaning liquid on the basis of ink concentration.SOLUTION: A recording device 11 includes a conveyance belt 25, a recording part 12 for discharging pigment ink to a medium 99, and thereby recording an image to the medium, and a cleaning mechanism 31 for cleaning the conveyance belt by a cleaning liquid, wherein the cleaning mechanism has a storage part 35 for storing the cleaning liquid, a first detection part 59 for detecting ink concentration of black ink contained in the cleaning liquid stored in the storage part, a second detection part 60 for detecting ink concentration of pigment ink contained in the cleaning liquid stored in the storage part, and a cleaning control part 65, the second detection part receives light scattering in the cleaning liquid, and thereby detects the ink concentration of the pigment ink, and the cleaning control part determines a threshold on the basis of the ink concentration of the black ink detected by the first detection part, and discharges the cleaning liquid from the storage part, when the ink concentration of the pigment ink detected by the second detection part is equal to or higher than a threshold.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a recording apparatus and a cleaning mechanism. [Background technology]

[0002] Patent Document 1 describes a recording device equipped with a cleaning mechanism that uses cleaning liquid to clean a conveyor belt that conveys a medium. In the cleaning mechanism, ink gets mixed into the cleaning liquid as the conveyor belt is cleaned. The cleaning mechanism detects the ink concentration of the cleaning liquid. If the ink concentration of the cleaning liquid is high, the cleaning mechanism discharges the cleaning liquid. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2008-213394 A Summary of the Invention [Problem to be solved by the invention]

[0004] The recording device described in Patent Document 1 detects the ink concentration based on the amount of light transmitted through the cleaning liquid. However, the amount of transmitted light varies depending on the color of the ink contained in the cleaning liquid. For example, when the cleaning liquid contains black ink, the amount of transmitted light is likely to be smaller than when the cleaning liquid does not contain black ink. Therefore, the recording device may not be able to properly discharge the cleaning liquid based on the ink concentration. [Means for solving the problem]

[0005] A recording device that solves the above problem includes a conveyor belt that conveys a medium, a recording unit that records an image on the medium by ejecting pigment ink onto the medium conveyed by the conveyor belt, and a cleaning mechanism that cleans the conveyor belt with cleaning liquid, wherein the pigment ink includes black ink and ink other than the black ink, and the cleaning mechanism has a storage unit that stores cleaning liquid, a first detection unit that detects the ink concentration of the black ink contained in the cleaning liquid stored in the storage unit, a second detection unit that detects the ink concentration of the pigment ink contained in the cleaning liquid stored in the storage unit, and a cleaning control unit, wherein the second detection unit detects the ink concentration of the pigment ink by receiving light scattered in the cleaning liquid, and the cleaning control unit determines a threshold value based on the ink concentration of the black ink detected by the first detection unit, and discharges the cleaning liquid from the storage unit when the ink concentration of the pigment ink detected by the second detection unit is equal to or greater than the threshold value.

[0006] A cleaning mechanism that solves the above problem is a cleaning mechanism that uses cleaning liquid to clean a conveying belt that conveys a medium on which an image is recorded by ejecting a pigment ink containing a black ink and an ink other than the black ink, and the cleaning mechanism has a storage section that stores cleaning liquid, a first detection section that detects the ink concentration of the black ink contained in the cleaning liquid stored in the storage section, a second detection section that detects the ink concentration of the pigment ink contained in the cleaning liquid stored in the storage section, and a cleaning control section, wherein the second detection section detects the ink concentration of the pigment ink by receiving light scattered in the cleaning liquid, and the cleaning control section determines a threshold value based on the ink concentration of the black ink detected by the first detection section, and discharges cleaning liquid from the storage section when the ink concentration of the pigment ink detected by the second detection section is equal to or greater than the threshold value. [Brief description of the drawings]

[0007] [Figure 1] FIG. 1 is a schematic diagram showing an embodiment of a recording apparatus equipped with a cleaning mechanism. [Diagram 2]FIG. 2 is a schematic diagram showing a detection unit. [Diagram 3] FIG. 3 is a graph showing the relationship between the wavelength of light and the transmittance of pigment ink. [Figure 4] FIG. 4 is a graph showing the relationship between the wavelength of light and the transmittance of pigment ink. [Diagram 5] FIG. 5 is a graph showing ink density and output level for pigment inks that do not include black ink. [Figure 6] FIG. 6 is a graph showing the ink concentration and output level of pigment inks including black ink. [Figure 7] FIG. 7 is a graph showing the output level that varies depending on the ink density of black ink and the ink density of pigment ink. [Figure 8] FIG. 8 is a schematic diagram showing a modified example of the detection flow channel. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] An embodiment of a recording device equipped with a cleaning mechanism will be described below with reference to the drawings. The recording device is, for example, an inkjet printer that records images such as characters and photographs by ejecting pigment ink onto a medium such as fabric or paper. Pigment ink is an ink in which a pigment is dispersed in a solvent. Pigment ink includes black ink and inks other than black ink. Pigment ink includes, for example, inks such as cyan, yellow, magenta, red, orange, green, and light black in addition to black.

[0009] <Recording device> As shown in FIG. 1, the recording device 11 includes a recording unit 12. The recording unit 12 is configured to eject pigment ink onto a medium 99. In this way, the recording unit 12 records an image on the medium 99. The recording unit 12 is a head. The recording unit 12 has a nozzle surface 14 in which one or more nozzles 13 are opened. The recording unit 12 ejects the pigment ink from the nozzles 13. The recording unit 12 may be a serial head that scans the medium 99. The recording unit 12 may be a line head that can eject pigment ink simultaneously across the width of the medium 99.

[0010] The recording device 11 includes a recording control unit 15. The recording control unit 15 controls the recording unit 12. The recording control unit 15 may also control a transport unit 21, which will be described later. The recording control unit 15 may be configured with one or more processors that execute various processes according to a computer program. The recording control unit 15 may be configured with one or more dedicated hardware circuits, such as application specific integrated circuits, that execute at least some of the various processes. The recording control unit 15 may be configured with a circuit including a combination of a processor and a hardware circuit. The processor includes a CPU and memory, such as RAM and ROM. The memory stores program code or instructions configured to cause the CPU to execute processes. The memory, i.e., computer-readable medium, includes any readable medium that can be accessed by a general-purpose or dedicated computer.

[0011] The recording device 11 includes a transport unit 21. The transport unit 21 is configured to transport a medium 99. In the process in which the transport unit 21 transports the medium 99, liquid is ejected from the recording unit 12 onto the medium 99.

[0012] The transport unit 21 is configured to transport the medium 99 in the transport direction A1. The transport unit 21 has a plurality of transport rollers. In one example, the transport unit 21 has a first transport roller 22 and a second transport roller 23. The first transport roller 22 is located upstream of the recording unit 12 in the transport direction A1. The second transport roller 23 is located downstream of the recording unit 12 in the transport direction A1.

[0013] The transport unit 21 has a driving source 24. The driving source 24 is, for example, a motor. The driving source 24 is connected to at least one of the multiple transport rollers. In one example, the driving source 24 is connected to the first transport roller 22. The first transport roller 22 is rotated by the driving source 24.

[0014] The transport unit 21 has a transport belt 25. The transport belt 25 is wound around a plurality of transport rollers. In one example, the transport belt 25 is wound around a first transport roller 22 and a second transport roller 23. The drive source 24 rotates the first transport roller 22, so that the transport belt 25 rotates along the first transport roller 22 and the second transport roller 23. In FIG. 1, the transport belt 25 rotates counterclockwise. As a result, the transport belt 25 transports the medium 99. The transport belt 25 supports the medium 99 on which an image is recorded by the recording unit 12.

[0015] The conveyor belt 25 includes a portion that moves in the conveying direction A1 and a portion that moves in an opposite direction A2 opposite to the conveying direction A1. The conveyor belt 25 conveys the medium 99 by the portion that moves in the conveying direction A1. The portion that moves in the opposite direction A2 is cleaned by a cleaning mechanism 31, which will be described later.

[0016] The transport belt 25 has an inner circumferential surface 26 and an outer circumferential surface 27. The inner circumferential surface 26 is a surface that contacts a plurality of transport rollers. In one example, the inner circumferential surface 26 contacts the first transport roller 22 and the second transport roller 23. The outer circumferential surface 27 is a surface that contacts the medium 99. Therefore, the outer circumferential surface 27 is a surface that supports the medium 99. The outer circumferential surface 27 faces the nozzle surface 14.

[0017] The conveyor belt 25 is configured to be capable of adhering the medium 99. More specifically, the medium 99 is adhered to the outer peripheral surface 27. This allows the medium 99 to be conveyed in a stable position. In one example, the conveyor belt 25 is an adhesive belt to which an adhesive is applied. The adhesive is applied to the outer peripheral surface 27. In this case, the medium 99 is adhered to the outer peripheral surface 27 by the adhesive. The medium 99 may be adhered to the outer peripheral surface 27 by, for example, suction force, electrostatic force, intermolecular force, etc., without being limited to the adhesive. After an image is recorded on the medium 99 by the recording unit 12, the medium 99 is peeled off from the outer peripheral surface 27 by, for example, being pulled by another device. The conveyor unit 21 may have a peeling unit that peels off the medium 99 from the outer peripheral surface 27. In this case, the peeling unit is, for example, a roller around which the medium 99 is wound.

[0018] The transport unit 21 may have a pressing unit 28. The pressing unit 28 is configured to press the medium 99 against the transport belt 25. In one example, the pressing unit 28 is a roller. The pressing unit 28 presses the medium 99 against the transport belt 25, so that the medium 99 is adhered to the outer circumferential surface 27.

[0019] In the conveyor belt 25, pigment ink may adhere to the outer peripheral surface 27 as the recording unit 12 records an image on the medium 99. If the conveyor belt 25 continues to convey the medium 99 with pigment ink adhered to the outer peripheral surface 27, the medium 99 may become soiled.

[0020] The recording device 11 includes a cleaning mechanism 31. The cleaning mechanism 31 is configured to clean the conveyor belt 25 with a cleaning liquid. More specifically, the cleaning mechanism 31 cleans the outer peripheral surface 27 with the cleaning liquid. The cleaning mechanism 31 removes pigment ink adhering to the outer peripheral surface 27 with the cleaning liquid. The cleaning liquid makes it easier for the pigment ink to fall off from the conveyor belt 25. In one example, the cleaning liquid is water.

[0021] <Cleaning mechanism> The cleaning mechanism 31 has a cleaning unit 32. The cleaning unit 32 cleans the conveyor belt 25 with a cleaning liquid. The cleaning unit 32 cleans the conveyor belt 25 by contacting the conveyor belt 25. More specifically, the cleaning unit 32 contacts the outer circumferential surface 27. The cleaning unit 32 contacts a portion of the conveyor belt 25 that is located in the opposite direction A2. That is, the cleaning unit 32 contacts the conveyor belt 25 after the medium 99 has been peeled off.

[0022] The cleaning unit 32 has one or more cleaning rollers 33. In one example, the cleaning unit 32 has three cleaning rollers 33. The cleaning rollers 33 come into contact with the conveyor belt 25 while rotating. The cleaning rollers 33 may rotate in a driven manner relative to the conveyor belt 25. That is, the cleaning rollers 33 may rotate in a driven manner clockwise in FIG. 1. The cleaning rollers 33 may rotate in a driven manner against the rotation of the conveyor belt 25. That is, the cleaning rollers 33 may rotate in a counterclockwise manner in FIG. 1. In this case, the contact resistance between the cleaning rollers 33 and the conveyor belt 25 increases, and therefore the pigment ink is easily removed from the conveyor belt 25.

[0023] The cleaning roller 33 comes into contact with the transport belt 25 while being wet with the cleaning liquid. As a result, the transport belt 25 is wet with the cleaning liquid, which makes it easier to remove the pigment ink from the transport belt 25. The cleaning roller 33 is, for example, a brush roller. The cleaning roller 33 may also be a sponge roller.

[0024] The cleaning unit 32 has one or more cleaning blades 34. In one example, the cleaning unit 32 has three cleaning blades 34. The cleaning blade 34 contacts the conveyor belt 25 wet with the cleaning liquid. The cleaning blade 34 contacts the outer circumferential surface 27 wet with the cleaning liquid. The cleaning blade 34 scrapes off the pigment ink together with the cleaning liquid adhering to the conveyor belt 25. The cleaning blade 34 contacts the conveyor belt 25 after the cleaning roller 33 contacts it. Therefore, the cleaning blade 34 is located in the opposite direction A2 from the cleaning roller 33.

[0025] The cleaning mechanism 31 includes a storage section 35. The storage section 35 is configured to store a cleaning liquid. The storage section 35 holds the cleaning section 32. The cleaning section 32 cleans the conveyor belt 25 by using the cleaning liquid stored in the storage section 35. The cleaning liquid stored in the storage section 35 gradually becomes dirty as the cleaning section 32 cleans the conveyor belt 25. Therefore, the cleaning mechanism 31 needs to replace the cleaning liquid stored in the storage section 35 as necessary.

[0026] The reservoir 35 has a cleaning tank 36. The cleaning tank 36 is a tank that stores a cleaning liquid used by the cleaning unit 32. The cleaning tank 36 is positioned to face the outer circumferential surface 27. The cleaning tank 36 holds the cleaning unit 32.

[0027] The cleaning tank 36 has an immersion tank 37. The immersion tank 37 is a tank that stores a predetermined amount of cleaning liquid. The immersion tank 37 holds the cleaning roller 33. The immersion tank 37 holds the cleaning roller 33 so that the cleaning roller 33 is immersed in the stored cleaning liquid. As the cleaning roller 33 cleans the conveyor belt 25, the pigment ink flows into the immersion tank 37.

[0028] The cleaning tank 36 has a support tank 38. The support tank 38 supports the immersion tank 37. More specifically, the support tank 38 accommodates the immersion tank 37. The support tank 38 receives the cleaning liquid that overflows from the immersion tank 37.

[0029] The support tank 38 supports the cleaning blade 34. The support tank 38 receives the cleaning liquid that flows down the cleaning blade 34. As the cleaning blade 34 cleans the transport belt 25, the pigment ink flows into the support tank 38.

[0030] The storage unit 35 has a storage tank 39. The storage tank 39 is a tank connected to the cleaning tank 36. The storage tank 39 stores the cleaning liquid after it has been used by the cleaning unit 32, and the cleaning liquid before it is used by the cleaning unit 32.

[0031] The storage section 35 has a plurality of connection flow paths. In one example, the storage section 35 has a first connection flow path 40 and a second connection flow path 41. The connection flow paths are flow paths connected to the cleaning tank 36 and the storage tank 39. In detail, the first connection flow path 40 is connected to the support tank 38 and the storage tank 39. The second connection flow path 41 is connected to the immersion tank 37 and the storage tank 39. The cleaning liquid flows from the cleaning tank 36 to the storage tank 39 through the first connection flow path 40. The cleaning liquid flows from the storage tank 39 to the cleaning tank 36 through the second connection flow path 41. In this way, in the storage section 35, the cleaning liquid circulates between the cleaning tank 36 and the storage tank 39. This makes it easier for the concentration of the pigment ink contained in the cleaning liquid to be uniform.

[0032] The storage section 35 has a detection flow path 42. A cleaning liquid flows through the detection flow path 42. The detection flow path 42 detects the ink concentration by a detection unit 58 described below. The detection unit 58 is attached to the detection flow path 42. The detection flow path 42 may be the same flow path as the connection flow path, or may be a flow path separate from the connection flow path. In one example, the detection flow path 42 constitutes a part of the first connection flow path 40. The detection flow path 42 may be a bypass flow path attached to the connection flow path.

[0033] 2, the detection flow path 42 has a first flow path portion 43 and a second flow path portion 44. The first flow path portion 43 is a flow path portion where the ink concentration is detected by a first detection unit 59 described later. The second flow path portion 44 is a flow path portion where the ink concentration is detected by a second detection unit 60 described later. In one example, the width of the first flow path portion 43 is smaller than the width of the second flow path portion 44.

[0034] The detection flow path 42 may have a reflection sheet 45. The reflection sheet 45 is a sheet that reflects light. In one example, the reflection sheet 45 reflects infrared light. The reflection sheet 45 is, for example, a white or silver resin sheet. The reflection sheet 45 is attached to the first flow path portion 43. In one example, the reflection sheet 45 is attached to the outer circumferential surface of the first flow path portion 43.

[0035] The detection flow path 42 may have a light-absorbing sheet 46. The light-absorbing sheet 46 is a sheet that absorbs light. In one example, the light-absorbing sheet 46 absorbs infrared light. The light-absorbing sheet 46 is, for example, a sheet coated with carbon. The light-absorbing sheet 46 is attached to the second flow path portion 44. In one example, the light-absorbing sheet 46 is attached to the outer circumferential surface of the second flow path portion 44.

[0036] As shown in FIG. 1, the cleaning mechanism 31 includes a supply flow path 47. The supply flow path 47 is a flow path through which a cleaning liquid is supplied. New cleaning liquid is supplied to the cleaning mechanism 31 through the supply flow path 47. The supply flow path 47 is connected to the storage unit 35. In one example, the supply flow path 47 is connected to a storage tank 39. The supply flow path 47 is connected to, for example, a water supply. When the amount of cleaning liquid in the storage unit 35 decreases due to evaporation of the cleaning liquid, discharge of the cleaning liquid, or the like, the cleaning liquid is supplied from the supply flow path 47 to the storage unit 35.

[0037] The cleaning mechanism 31 includes a discharge flow path 48. The discharge flow path 48 is a flow path through which the cleaning liquid is discharged. The cleaning liquid is discharged from the cleaning mechanism 31 through the discharge flow path 48. In one example, the discharge flow path 48 is connected to the storage tank 39. The discharge flow path 48 is connected to, for example, a processing device that processes waste liquid, a waste liquid tank that stores waste liquid, or the like. When the cleaning liquid becomes contaminated by the pigment ink, the cleaning liquid is discharged from the storage unit 35 through the discharge flow path 48.

[0038] The cleaning mechanism 31 includes a pump 49. The pump 49 circulates the cleaning liquid in the storage section 35. The pump 49 circulates the cleaning liquid between the cleaning tank 36 and the storage tank 39 through the first connection flow path 40 and the second connection flow path 41. In one example, the pump 49 is located in the second connection flow path 41. The pump 49 may be located in the first connection flow path 40.

[0039] The cleaning mechanism 31 includes a flowmeter 50. The flowmeter 50 measures the flow rate of the cleaning liquid flowing in the storage section 35. The flowmeter 50 measures the flow rate of the cleaning liquid circulating between the cleaning tank 36 and the storage tank 39. The cleaning mechanism 31 controls the pump 49 based on the measurement result of the flowmeter 50. In one example, the flowmeter 50 is located in the second connection flow path 41. More specifically, the flowmeter 50 is located in the second connection flow path 41 between the pump 49 and the storage tank 39. The flowmeter 50 may be located in the first connection flow path 40.

[0040] The cleaning mechanism 31 includes a constant flow valve 51. The constant flow valve 51 is configured to maintain a constant flow rate of the cleaning liquid flowing in the storage section 35. The constant flow valve 51 is a so-called throttle valve. The constant flow valve 51 maintains a constant flow rate of the cleaning liquid circulating between the cleaning tank 36 and the storage tank 39. In one example, the constant flow valve 51 is located in the second connection flow path 41. More specifically, the constant flow valve 51 is located in the second connection flow path 41 between the pump 49 and the cleaning tank 36. The constant flow valve 51 may be located in the first connection flow path 40.

[0041] The cleaning mechanism 31 has one or more on-off valves. In one example, the cleaning mechanism 31 includes a first on-off valve 52, a second on-off valve 53, and a third on-off valve 54. The on-off valves are, for example, solenoid valves. The first on-off valve 52 is located in the first connection flow path 40. When the first on-off valve 52 is opened, the cleaning liquid can flow from the cleaning tank 36 to the storage tank 39. The second on-off valve 53 is located in the supply flow path 47. When the second on-off valve 53 is opened, the cleaning liquid is supplied to the storage section 35. The third on-off valve 54 is located in the discharge flow path 48. When the third on-off valve 54 is opened, the cleaning liquid is discharged from the storage section 35.

[0042] The cleaning mechanism 31 may include a liquid level sensor 55. The liquid level sensor 55 is a sensor that measures the amount of cleaning liquid stored in the storage section 35. In one example, the liquid level sensor 55 measures the amount of cleaning liquid stored in the storage tank 39. The cleaning mechanism 31 can maintain the amount of cleaning liquid stored in the storage section 35 at a constant amount by using the liquid level sensor 55. For example, when the amount of cleaning liquid stored in the storage tank 39 is large, the cleaning mechanism 31 discharges the cleaning liquid through the discharge flow path 48. When the amount of cleaning liquid stored in the storage tank 39 is small, the cleaning mechanism 31 supplies the cleaning liquid through the supply flow path 47.

[0043] The cleaning mechanism 31 may include one or more filters. The cleaning mechanism 31 includes a cleaning filter 56 and a storage filter 57. The filters collect dust, fluff, and the like in the cleaning liquid. The cleaning filter 56 is attached to the first connection flow path 40. More specifically, the cleaning filter 56 is located at an end of the first connection flow path 40 that is connected to the cleaning tank 36. The cleaning filter 56 collects foreign matter from the cleaning liquid flowing from the cleaning tank 36 to the storage tank 39. The storage filter 57 is attached to the first connection flow path 40. More specifically, the storage filter 57 is located at an end of the first connection flow path 40 that is connected to the storage tank 39. The storage filter 57 collects foreign matter from the cleaning liquid flowing from the cleaning tank 36 to the storage tank 39.

[0044] The cleaning mechanism 31 includes a detection unit 58. The detection unit 58 is configured to detect the ink concentration of the pigment ink contained in the cleaning liquid stored in the storage section 35. The detection unit 58 detects the ink concentration of the cleaning liquid flowing through the detection flow path 42. The cleaning mechanism 31 discharges the cleaning liquid when the ink concentration of the pigment ink contained in the cleaning liquid is high. When the ink concentration of the pigment ink contained in the cleaning liquid becomes high, the cleaning ability of the cleaning mechanism 31 decreases. By discharging the cleaning liquid when the ink concentration of the pigment ink contained in the cleaning liquid is high, the amount of cleaning liquid used is reduced compared to a configuration in which the cleaning liquid is constantly supplied.

[0045] In the storage section 35, the pigment constituting the pigment ink is dispersed in the cleaning liquid. The detection unit 58 detects the ink concentration of the pigment ink by detecting the pigment dispersed in the cleaning liquid. The detection unit 58 optically detects the pigment dispersed in the cleaning liquid. There are a transmission method and a scattering method as methods for optically detecting the pigment dispersed in the cleaning liquid. The transmission method is a method for detecting the pigment based on the amount of transmitted light that passes through the cleaning liquid. In other words, the transmission method is a method that utilizes the absorption of light by the pigment. The scattering method is a method for detecting the pigment based on the amount of scattered light scattered by the cleaning liquid. In other words, the scattering method is a method that utilizes the reflection of light by the pigment.

[0046] As shown in Figs. 3 and 4, the transmittance, i.e., absorbance, of the pigment ink varies depending on the color of the pigment ink. The graphs shown in Figs. 3 and 4 show the transmittance when a cleaning solution containing a single color ink is irradiated with light. The black ink shown by the two-dot chain line in Fig. 3 is absorbent regardless of the wavelength of light. More specifically, the black ink is absorbent for light having a wavelength of 300 nm to 1100 nm. The cyan ink shown by the solid line in Fig. 3 is absorbent for light having a wavelength of 540 nm to 740 nm. The magenta ink shown by the one-dot chain line in Fig. 3 is absorbent for light having a wavelength of 500 nm to 580 nm. The yellow ink shown by the dashed line in Fig. 3 is absorbent for light having a wavelength of 340 nm to 500 nm. The red ink shown by the solid line in Fig. 4 is absorbent for light having a wavelength of 300 nm to 620 nm. The orange ink shown by the dashed line in Fig. 4 is absorbent for light having a wavelength of 300 nm to 580 nm. The green ink shown by the dashed line in Figure 4 is absorbent for light with wavelengths from 580 nm to 780 nm, while the light black ink shown by the dashed line in Figure 4 is absorbent for light with wavelengths from 300 nm to 780 nm.

[0047] The greater the ink concentration of the pigment ink, the smaller the amount of light transmitted through the cleaning liquid. Meanwhile, the amount of transmitted light varies depending on the color of the pigment ink scattered in the cleaning liquid. This is because the wavelength range of light that exhibits absorbency differs depending on the color of the pigment ink. In other words, when light of a specific wavelength is irradiated onto the cleaning liquid, the ink concentration of a color that exhibits absorbency to that light can be detected, but the ink concentration of a color that does not exhibit absorbency to that light cannot be detected. For this reason, it is difficult to detect the ink concentration of the pigment ink for a cleaning liquid that contains pigments of multiple colors based on the amount of transmitted light.

[0048] In contrast to the transmission method, the scattering method uses light in a wavelength range that is less absorbed by pigments, making it possible to detect the ink concentration of pigment ink relatively independent of color. For example, by using infrared light with a wavelength of 800 nm or more, the detection unit 58 can detect the ink concentration of pigment ink for cleaning liquid containing pigments of multiple colors. Therefore, the detection unit 58 detects the ink concentration of pigment ink based on the amount of scattered light.

[0049] The greater the ink concentration of the pigment ink, the greater the amount of scattered light. Meanwhile, the amount of scattered light varies depending on the color of the pigment ink scattered in the cleaning fluid. More specifically, if the ink concentration of the black ink contained in the cleaning fluid is high, the amount of scattered light is small despite the high ink concentration of the pigment ink. This is because black ink is absorbent not only to visible light but also to infrared light.

[0050] As shown in Figure 5, when the cleaning liquid does not contain black ink, the ink concentration and the output level are proportional to each other. The output level is a level indicated by the amount of scattered light. In other words, the higher the ink concentration of the pigment ink, the greater the amount of scattered light.

[0051] As shown in Figure 6, when the cleaning liquid contains black ink, the ink density and the output level are in a proportional relationship, just as when the cleaning liquid does not contain black ink. In other words, the greater the ink density of the pigment ink, the greater the amount of scattered light. On the other hand, when the cleaning liquid contains black ink, the output level relative to the ink density is smaller than when the cleaning liquid does not contain black ink.

[0052] As shown in Figure 7, the greater the ink concentration of the black ink contained in the cleaning fluid, the smaller the output level. In other words, even if the ink concentration of the pigment ink contained in the cleaning fluid is the same, the amount of scattered light varies depending on the ink concentration of the black ink. For this reason, it is difficult to uniquely determine the ink concentration of the pigment ink based on the amount of scattered light.

[0053] The ink density of the black ink determines the correspondence relationship between the ink density of the pigment ink and the amount of scattered light. That is, the ink density of the pigment ink is determined from the amount of scattered light based on the ink density of the black ink. Therefore, the detection unit 58 detects the ink density of the black ink and the ink density of the pigment ink.

[0054] As shown in FIG. 2, the detection unit 58 has a first detection section 59 and a second detection section 60. The first detection section 59 is configured to detect the ink density of black ink. That is, the first detection section 59 detects the ink density of black ink among the pigment inks of each color used by the recording section 12. The second detection section 60 is configured to detect the ink density of the pigment ink. That is, the second detection section 60 detects the ink density of the pigment inks of multiple colors used by the recording section 12.

[0055] The first detection unit 59 and the second detection unit 60 detect the ink concentration of the cleaning liquid stored in the storage unit 35. In one example, the first detection unit 59 and the second detection unit 60 detect the ink concentration of the cleaning liquid flowing through the first connection flow path 40. In this case, the first detection unit 59 and the second detection unit 60 detect the ink concentration of the cleaning liquid flowing out of the cleaning tank 36. Therefore, the first detection unit 59 and the second detection unit 60 can accurately detect the ink concentration of the cleaning liquid used to clean the conveyor belt 25. The first detection unit 59 and the second detection unit 60 may detect the ink concentration of the cleaning liquid flowing through the second connection flow path 41.

[0056] The first detection unit 59 and the second detection unit 60 are optical sensors. The first detection unit 59 and the second detection unit 60 each have a light emitting unit and a light receiving unit. More specifically, the first detection unit 59 has a first light emitting unit 61 and a first light receiving unit 62. The second detection unit 60 has a second light emitting unit 63 and a second light receiving unit 64. The light emitting unit includes an element that emits light. The light emitting unit includes, for example, an LED. The light emitting unit emits light of a predetermined wavelength. The light receiving unit includes an element that outputs a signal by receiving light. The light receiving unit includes, for example, a photodiode. The light receiving unit receives light emitted by the light emitting unit. The first light receiving unit 62 receives light from the first light emitting unit 61. The second light receiving unit 64 receives light from the second light emitting unit 63.

[0057] In order to detect the ink density of black ink, the first detection unit 59 uses light of a wavelength that black ink is absorbent and other inks are not absorbent. In one example, the first light emitter 61 emits infrared light with a wavelength of 850 nm. The first light receiver 62 receives the transmitted light. In this way, the first detection unit 59 detects the ink density of black ink.

[0058] The second detection unit 60 uses light of a wavelength that is not absorbed by the pigment inks of multiple colors in order to detect the ink concentration of the pigment ink containing multiple colors. In one example, the second light-emitting unit 63 emits infrared light with a wavelength of 850 nm, similar to the first light-emitting unit 61. The second light-receiving unit 64 receives the scattered light. In this way, the second detection unit 60 detects the ink concentration of the pigment ink. The first light-emitting unit 61 and the second light-emitting unit 63 may be configured with a common LED.

[0059] The first detection unit 59 detects the ink concentration of the cleaning liquid flowing through the first flow path portion 43. The first light emitter 61 emits light toward the first flow path portion 43. The light is reflected by the reflection sheet 45 and then enters the first light receiver 62. As a result, the first detection unit 59 detects the transmitted light. The reflection sheet 45 eliminates the need to face the first light emitter 61 and the first light receiver 62 across the first flow path portion 43. That is, the first light emitter 61 and the first light receiver 62 do not need to be positioned so as to sandwich the first flow path portion 43. In one example, the first light emitter 61 and the first light receiver 62 are aligned along the first flow path portion 43. In this way, the reflection sheet 45 improves the degree of freedom regarding the positions of the first light emitter 61 and the first light receiver 62. In addition, since the width of the first flow path portion 43 is relatively small, the optical path from the first light emitter 61 to the first light receiver 62 is small. This allows the first detection unit 59 to detect a large amount of transmitted light, and therefore the first detection unit 59 can detect the ink density of black ink with high accuracy.

[0060] The second detection unit 60 detects the ink concentration of the cleaning liquid flowing through the second flow path portion 44. The second light emitter 63 and the second light receiver 64 are aligned along the second flow path portion 44. The second light emitter 63 emits light toward the second flow path portion 44. The light is diffused in the cleaning liquid and then enters the second light receiver 64. This allows the second detection unit 60 to detect the scattered light. The light absorbing sheet 46 makes it difficult for light to be reflected on the outer peripheral surface of the second flow path portion 44. In other words, the reflected light is unlikely to enter the second light receiver 64. Therefore, the second detection unit 60 can detect the scattered light with high accuracy. In addition, since the width of the second flow path portion 44 is relatively large, the light emitted from the second light emitter 63 is easily diffused by the pigment in the cleaning liquid. This allows the second detection unit 60 to detect a large amount of scattered light. Therefore, the second detection unit 60 can detect the ink concentration of the pigment ink with high accuracy.

[0061] 1, the cleaning mechanism 31 includes a cleaning control unit 65. The cleaning control unit 65 controls the cleaning mechanism 31. Like the recording control unit 15, the cleaning control unit 65 may be configured with a processor, may be configured with a hardware circuit, or may be configured with a circuit including a combination thereof. The cleaning mechanism 31 may be controlled by the recording control unit 15.

[0062] The cleaning control unit 65 determines the threshold value for the amount of scattered light based on the ink concentration of the black ink contained in the cleaning liquid. That is, the cleaning control unit 65 changes the threshold value based on the ink concentration of the black ink contained in the cleaning liquid detected by the first detection unit 59. The cleaning control unit 65 determines whether the cleaning liquid is contaminated by changing the threshold value in accordance with the amount of scattered light that varies depending on the ink concentration of the black ink contained in the cleaning liquid.

[0063] The cleaning control unit 65 stores the correspondence data D1. The correspondence data D1 is data in which the ink density of black ink and a threshold value are associated with each other. The correspondence data D1 may be table data indicating the correspondence relationship between the ink density of black ink and a threshold value, or may be function data for deriving a threshold value from the ink density of black ink. The correspondence data D1 may be stored in the recording control unit 15.

[0064] The cleaning control unit 65 determines the threshold value from the detection result of the first detection unit 59 by referring to the correspondence data D1. For example, when the ink density of black ink is a first density, the cleaning control unit 65 sets a first threshold value. When the ink density of black ink is a second density, the cleaning control unit 65 sets a second threshold value. The higher the ink density of black ink, the smaller the threshold value set by the cleaning control unit 65.

[0065] The cleaning control unit 65 compares the detection result of the second detection unit 60 with a threshold value to determine whether or not to drain the cleaning liquid. When the ink concentration of the pigment ink is equal to or higher than the threshold value, the cleaning control unit 65 drains the cleaning liquid from the storage unit 35. At this time, the cleaning control unit 65 drains the cleaning liquid from the storage unit 35 by opening the third on-off valve 54. After completing the drainage of the cleaning liquid, the cleaning control unit 65 supplies the cleaning liquid to the storage unit 35 by opening the second on-off valve 53. This replaces the cleaning liquid.

[0066] When discharging the cleaning liquid, the cleaning control unit 65 may determine whether the recording device 11 is recording or not. The cleaning control unit 65 may determine whether the recording device 11 is recording or not by communicating with the recording control unit 15. The cleaning control unit 65 may determine whether the recording device 11 is recording or not by receiving an operation from a user. When the recording device 11 is recording, it is preferable that the cleaning liquid is stored in the cleaning tank 36. Therefore, when the recording device 11 is recording, the cleaning control unit 65 discharges the cleaning liquid from the storage tank 39 by opening the second opening / closing valve 53 with the first opening / closing valve 52 closed. As a result, the cleaning liquid is retained in the cleaning tank 36, while the cleaning liquid is replaced in the storage tank 39.

[0067] <Action and Effects> Next, the operation and effects of the above embodiment will be described. (1) The cleaning control unit 65 determines the threshold value based on the ink concentration of the black ink. When the ink concentration of the pigment ink is equal to or higher than the threshold value, the cleaning control unit 65 discharges the cleaning liquid from the storage unit 35. When the ink concentration of the black ink contained in the cleaning liquid is high, the amount of scattered light received by the second detection unit 60 is small. When the ink concentration of the black ink contained in the cleaning liquid is low, the amount of scattered light received by the second detection unit 60 is large. That is, even if the ink concentration of the pigment ink contained in the cleaning liquid is the same, if the ink concentration of the black ink is different, the amount of scattered light received by the second detection unit 60 is different. Therefore, it is difficult to grasp the ink concentration of the pigment ink based on the amount of scattered light. In this regard, according to the above configuration, since the threshold value is determined based on the ink concentration of the black ink, even if the amount of scattered light received by the second detection unit 60 changes depending on the ink concentration of the black ink, the ink concentration of the pigment ink can be grasped based on the amount of scattered light. Therefore, the cleaning mechanism 31 can appropriately discharge the cleaning liquid based on the ink concentration.

[0068] (2) The first detection unit 59 detects the ink concentration of the black ink by receiving light transmitted through the cleaning fluid with the first light receiving unit 62. The second detection unit 60 detects the ink concentration of the pigment ink by receiving light scattered in the cleaning fluid with the second light receiving unit 64. The pigment of black ink absorbs light more easily than pigments other than black ink. Therefore, with the above configuration, the first detection unit 59 can detect the ink concentration of the black ink based on the amount of light transmitted through the cleaning fluid. This allows the cleaning control unit 65 to appropriately determine the threshold value.

[0069] (3) The width of the first flow path portion 43 is smaller than the width of the second flow path portion 44. To increase the amount of light transmitted through the cleaning liquid, it is preferable that the width of the first flow path portion 43 is small. To increase the amount of light scattered by the cleaning liquid, it is preferable that the width of the second flow path portion 44 is large. With the above configuration, it becomes easier for the first detection unit 59 to detect the ink concentration of black ink, and it becomes easier for the second detection unit 60 to detect the ink concentration of pigment ink.

[0070] (4) The detection flow path 42 has a reflection sheet 45 that reflects light emitted by the first light emitter 61 toward the first light receiver 62. According to the above configuration, the first light receiver 62 can receive light transmitted through the cleaning liquid without disposing the first light emitter 61 and the first light receiver 62 so as to sandwich the first flow path portion 43. This allows the first light emitter 61 and the first light receiver 62 to be located together in one place.

[0071] (5) The detection flow path 42 has a light absorbing sheet 46 that absorbs light emitted by the second light emitter 63. The light emitted by the second light emitter 63 may be reflected by the second flow path portion 44. When this reflected light is received by the second light receiver 64, the detection accuracy of the second detection unit 60 decreases. In this regard, according to the above configuration, the reflected light is reduced by the light absorbing sheet 46, thereby reducing the risk of the detection accuracy of the second detection unit 60 decreasing.

[0072] (6) The cleaning mechanism 31 has a pump 49 that circulates the cleaning liquid between the cleaning tank 36 and the storage tank 39 through the first connection flow path 40 and the second connection flow path 41. With the above configuration, the ink concentration of the pigment ink contained in the cleaning liquid tends to become uniform by circulating the cleaning liquid. Therefore, the detection accuracy of the first detection unit 59 and the detection accuracy of the second detection unit 60 are improved.

[0073] (7) The first detection unit 59 detects the ink concentration of the black ink contained in the cleaning liquid flowing through the first connection flow path 40. The second detection unit 60 detects the ink concentration of the pigment ink contained in the cleaning liquid flowing through the first connection flow path 40. In the cleaning tank 36, the pigment ink is mixed into the cleaning liquid. Therefore, the ink concentration of the pigment ink contained in the cleaning liquid flowing through the first connection flow path 40 tends to be greater than the ink concentration of the pigment ink contained in the cleaning liquid flowing through the second connection flow path 41. The same is true for the ink concentration of the black ink. Therefore, with the above configuration, the detection accuracy of the first detection unit 59 and the detection accuracy of the second detection unit 60 are improved.

[0074] (8) The cleaning control unit 65 determines the threshold value based on the ink density of black ink by referring to the correspondence data D1. With the above configuration, the cleaning control unit 65 can determine the threshold value relatively easily.

[0075] <Example of change> The above embodiment can be modified as follows: The above embodiment and the following modified examples can be combined with each other to the extent that there is no technical contradiction.

[0076] As shown in FIG. 8, the reflection sheet 45 and the light absorbing sheet 46 may be located in the first flow path portion 43 and the second flow path portion 44. In this modification, the reflection sheet 45 and the light absorbing sheet 46 are located in the first flow path portion 43 and the second flow path portion 44 in a state where they are attached to each other. The reflection sheet 45 and the light absorbing sheet 46 branch the detection flow path 42 into the first flow path portion 43 and the second flow path portion 44. The reflection sheet 45 and the light absorbing sheet 46 define the first flow path portion 43 and the second flow path portion 44. The first flow path portion 43 is a portion of the detection flow path 42 that faces the reflection sheet 45. The second flow path portion 44 is a portion of the detection flow path 42 that faces the light absorbing sheet 46. In this modification, the first detection unit 59 and the second detection unit 60 are located so as to sandwich the detection flow path 42.

[0077] The first detection unit 59 and the second detection unit 60 may each detect the cleaning liquid flowing through a different connection flow path. For example, the first detection unit 59 may detect the cleaning liquid flowing through the first connection flow path 40, while the second detection unit 60 may detect the cleaning liquid flowing through the second connection flow path 41. In this case, the first connection flow path 40 and the second connection flow path 41 each have a detection flow path 42.

[0078] The first detection unit 59 is not limited to detecting the ink concentration of black ink by the transmission method. For example, the first detection unit 59 may detect the ink concentration of black ink by detecting the pH of the cleaning liquid. In this case, the black ink contains a component that changes the pH of the cleaning liquid. Also, the first detection unit 59 may detect the ink concentration of black ink by detecting a component contained in the black ink from the cleaning liquid, not limited to the pH.

[0079] The liquid discharged by the recording unit 12 is not limited to ink, and may be, for example, a liquid in which particles of a functional material are dispersed or mixed in a liquid. For example, the recording unit 12 may discharge a liquid containing, in a dispersed or dissolved form, a material such as an electrode material or a pixel material used in the manufacture of liquid crystal displays, electroluminescence displays, and surface-emitting displays.

[0080] <Technical philosophy> The technical ideas and effects obtained from the above-mentioned embodiment and modified examples will be described below.

[0081] (A) A recording device includes a conveyor belt that conveys a medium, a recording unit that records an image on the medium by ejecting pigment ink onto the medium conveyed by the conveyor belt, and a cleaning mechanism that cleans the conveyor belt with cleaning liquid, wherein the pigment ink includes black ink and ink other than the black ink, and the cleaning mechanism has a storage unit that stores cleaning liquid, a first detection unit that detects the ink concentration of the black ink contained in the cleaning liquid stored in the storage unit, a second detection unit that detects the ink concentration of the pigment ink contained in the cleaning liquid stored in the storage unit, and a cleaning control unit, wherein the second detection unit detects the ink concentration of the pigment ink by receiving light scattered in the cleaning liquid, and the cleaning control unit determines a threshold value based on the ink concentration of the black ink detected by the first detection unit, and discharges the cleaning liquid from the storage unit when the ink concentration of the pigment ink detected by the second detection unit is equal to or greater than the threshold value.

[0082] When the ink concentration of the black ink contained in the cleaning liquid is high, the amount of scattered light received by the second detection unit is small. When the ink concentration of the black ink contained in the cleaning liquid is low, the amount of scattered light received by the second detection unit is large. In other words, even if the ink concentration of the pigment ink contained in the cleaning liquid is the same, if the ink concentration of the black ink is different, the amount of scattered light received by the second detection unit is different. Therefore, it is difficult to grasp the ink concentration of the pigment ink based on the amount of scattered light. In this regard, according to the above configuration, since the threshold value is determined based on the ink concentration of the black ink, even if the amount of scattered light received by the second detection unit changes depending on the ink concentration of the black ink, the ink concentration of the pigment ink can be grasped based on the amount of scattered light. Therefore, the cleaning mechanism can appropriately discharge the cleaning liquid based on the ink concentration.

[0083] (B) In the above recording device, the first detection unit may have a first light-emitting unit that emits light and a first light-receiving unit that receives light from the first light-emitting unit, and detect the ink concentration of the black ink by the first light-receiving unit receiving the light that has passed through the cleaning fluid, and the second detection unit may have a second light-emitting unit that emits light and a second light-receiving unit that receives the light from the second light-emitting unit, and detect the ink concentration of the pigment ink by the second light-receiving unit receiving the light scattered in the cleaning fluid.

[0084] The pigment in black ink absorbs light more easily than pigments other than black ink. Therefore, with the above configuration, the first detection unit can detect the ink concentration of the black ink based on the amount of light transmitted through the cleaning liquid. This allows the cleaning control unit to appropriately determine the threshold value.

[0085] (C) In the above recording device, the storage section has a detection flow path through which cleaning liquid flows, and the detection flow path has a first flow path portion where ink concentration is detected by the first detection section, and a second flow path portion where ink concentration is detected by the second detection section, and a width of the first flow path portion may be smaller than a width of the second flow path portion.

[0086] In order to increase the amount of light transmitted through the cleaning liquid, it is preferable that the width of the first flow path portion is small. In order to increase the amount of light scattered by the cleaning liquid, it is preferable that the width of the second flow path portion is large. With the above configuration, it becomes easier for the first detection unit to detect the ink concentration of the black ink, and it becomes easier for the second detection unit to detect the ink concentration of the pigment ink.

[0087] (D) In ​​the above recording device, the storage section has a detection flow path through which cleaning liquid flows, and the detection flow path has a first flow path portion where ink concentration is detected by the first detection section, a second flow path portion where ink concentration is detected by the second detection section, and a reflective sheet that reflects light from the first light emitter toward the first light receiver, and the first light emitter and the first light receiver may be aligned along the first flow path portion.

[0088] According to the above configuration, the first light-receiving unit can receive light transmitted through the cleaning liquid without disposing the first light-emitting unit and the first light-receiving unit so as to sandwich the first flow path portion between them. This allows the first light-emitting unit and the first light-receiving unit to be located together in one place.

[0089] (E) In the above recording device, the storage section has a detection flow path through which cleaning liquid flows, and the detection flow path has a first flow path portion where ink concentration is detected by the first detection section, a second flow path portion where ink concentration is detected by the second detection section, and a light-absorbing sheet that absorbs light from the second light-emitting section, and the second light-emitting section and the second light-receiving section may be aligned along the second flow path portion.

[0090] The light from the second light emitter may be reflected by the second flow path portion. When the second light receiver receives this reflected light, the detection accuracy of the second detector decreases. In this regard, according to the above configuration, the reflected light is reduced by the light absorbing sheet, so that the risk of the detection accuracy of the second detector decreasing is reduced.

[0091] (F) In the above recording device, the storage section may have a cleaning tank, a storage tank, a first connection flow path connected to the cleaning tank and the storage tank, and a second connection flow path connected to the cleaning tank and the storage tank, and the cleaning mechanism may have a cleaning section that cleans the conveying belt with cleaning liquid stored in the cleaning tank, and a pump that circulates the cleaning liquid between the cleaning tank and the storage tank through the first connection flow path and the second connection flow path.

[0092] According to the above configuration, the ink concentration of the pigment ink contained in the cleaning liquid tends to become uniform by circulating the cleaning liquid, thereby improving the detection accuracy of the first detection unit and the detection accuracy of the second detection unit.

[0093] (G) In the above recording device, the pump may send cleaning liquid from the cleaning tank to the storage tank through the first connection flow path, and send cleaning liquid from the storage tank to the cleaning tank through the second connection flow path, the first detection unit may detect an ink concentration of the black ink contained in the cleaning liquid flowing through the first connection flow path, and the second detection unit may detect an ink concentration of the pigment ink contained in the cleaning liquid flowing through the first connection flow path.

[0094] In the cleaning tank, the pigment ink is mixed into the cleaning liquid. Therefore, the ink concentration of the pigment ink contained in the cleaning liquid flowing through the first connection flow path is likely to be greater than the ink concentration of the pigment ink contained in the cleaning liquid flowing through the second connection flow path. The same is true for the ink concentration of black ink. Therefore, with the above configuration, the detection accuracy of the first detection unit and the detection accuracy of the second detection unit are improved.

[0095] (H) In the recording device, the cleaning control unit may store correspondence data in which the ink density of the black ink corresponds to the threshold value, and may determine the threshold value based on the ink density of the black ink by referring to the correspondence data. With the above configuration, the cleaning control unit can determine the threshold value relatively easily.

[0096] (I) A cleaning mechanism is a cleaning mechanism that uses cleaning liquid to clean a conveyor belt that conveys a medium on which an image is recorded by ejecting a pigment ink containing a black ink and an ink other than the black ink, the cleaning mechanism having a storage unit that stores cleaning liquid, a first detection unit that detects the ink concentration of the black ink contained in the cleaning liquid stored in the storage unit, a second detection unit that detects the ink concentration of the pigment ink contained in the cleaning liquid stored in the storage unit, and a cleaning control unit, the second detection unit detects the ink concentration of the pigment ink by receiving light scattered in the cleaning liquid, the cleaning control unit determines a threshold value based on the ink concentration of the black ink detected by the first detection unit, and discharges cleaning liquid from the storage unit when the ink concentration of the pigment ink detected by the second detection unit is equal to or greater than the threshold value. With the above configuration, an effect similar to that of a recording device can be obtained. [Explanation of symbols]

[0097] Reference Signs List 11...recording device, 12...recording section, 13...nozzle, 14...nozzle surface, 15...recording control section, 21...transport section, 22...first transport roller, 23...second transport roller, 24...driving source, 25...transport belt, 26...inner circumferential surface, 27...outer circumferential surface, 28...pressing section, 31...cleaning mechanism, 32...cleaning section, 33...cleaning roller, 34...cleaning blade, 35...storage section, 36...cleaning tank, 37...immersion tank, 38...support tank, 39...storage tank, 40...first connection flow path, 41...second connection flow path, 42...detection flow path, 43...first flow path portion, 44...second flow path part, 45...reflective sheet, 46...light-absorbing sheet, 47...supply flow path, 48...discharge flow path, 49...pump, 50...flow meter, 51...constant flow valve, 52...first on-off valve, 53...second on-off valve, 54...third on-off valve, 55...liquid level sensor, 56...cleaning filter, 57...containing filter, 58...detection unit, 59...first detection section, 60...second detection section, 61...first light-emitting section, 62...first light-receiving section, 63...second light-emitting section, 64...second light-receiving section, 65...cleaning control section, 99...medium, A1...transport direction, A2...opposite direction, D1...corresponding data.

Claims

1. A conveyor belt for conveying a medium; a recording unit that records an image on a medium by ejecting a pigment ink onto the medium transported by the transport belt; a cleaning mechanism for cleaning the conveyor belt with a cleaning liquid; the pigment ink includes a black ink and an ink other than the black ink, The cleaning mechanism includes: a storage section for storing a cleaning liquid; a first detection unit that detects an ink concentration of the black ink contained in the cleaning liquid stored in the storage unit; a second detection unit that detects an ink concentration of the pigment ink contained in the cleaning liquid stored in the storage unit; A cleaning control unit, the second detection unit detects the ink concentration of the pigment ink by receiving light scattered by the cleaning liquid; The cleaning control unit is determining a threshold value based on the ink density of the black ink detected by the first detection unit; a cleaning liquid storage section that stores a cleaning liquid when the ink concentration of the pigment ink detected by the second detection section is equal to or higher than the threshold value;

2. The first detection unit is A first light emitting unit that emits light; A first light receiving unit that receives light from the first light emitting unit, the first light receiving unit receives the light that has passed through the cleaning liquid, thereby detecting the ink concentration of the black ink; The second detection unit is A second light emitting unit that emits light; A second light receiving unit that receives light from the second light emitting unit, 2. The recording apparatus according to claim 1, wherein the ink concentration of the pigment ink is detected by receiving light scattered by the cleaning liquid at the second light receiving portion.

3. the reservoir has a detection flow path through which a cleaning liquid flows, The detection flow path is a first flow path portion in which the ink concentration is detected by the first detection unit; a second flow path portion in which the ink concentration is detected by the second detection unit, 3. The recording apparatus according to claim 2, wherein a width of the first flow path portion is smaller than a width of the second flow path portion.

4. the reservoir has a detection flow path through which a cleaning liquid flows, The detection flow path is a first flow path portion in which the ink concentration is detected by the first detection unit; a second flow path portion in which the ink concentration is detected by the second detection unit; a reflection sheet that reflects the light from the first light emitting unit toward the first light receiving unit, 3. The recording apparatus according to claim 2, wherein the first light emitting portion and the first light receiving portion are aligned along the first flow path portion.

5. the reservoir has a detection flow path through which a cleaning liquid flows, The detection flow path is a first flow path portion in which the ink concentration is detected by the first detection unit; a second flow path portion in which the ink concentration is detected by the second detection unit; a light absorbing sheet that absorbs the light from the second light emitting portion, 3. The recording apparatus according to claim 2, wherein the second light emitting portion and the second light receiving portion are aligned along the second flow path portion.

6. The storage section includes: A cleaning tank; A storage tank; a first connection flow path connected to the cleaning tank and the storage tank; a second connection flow path connected to the cleaning tank and the storage tank, The cleaning mechanism includes: a cleaning unit that cleans the conveyor belt with a cleaning liquid stored in the cleaning tank; 2. The recording apparatus according to claim 1, further comprising a pump for circulating the cleaning liquid between the cleaning tank and the storage tank through the first connection flow path and the second connection flow path.

7. The pump sends the cleaning liquid from the cleaning tank to the storage tank through the first connection flow path, and sends the cleaning liquid from the storage tank to the cleaning tank through the second connection flow path; the first detection unit detects an ink concentration of the black ink contained in the cleaning liquid flowing through the first connection flow path, 7. The recording apparatus according to claim 6, wherein the second detection section detects the ink concentration of the pigment ink contained in the cleaning liquid flowing through the first connection flow path.

8. The cleaning control unit is storing correspondence data in which the ink density of the black ink is associated with the threshold value; 8. The printing apparatus according to claim 1, wherein the threshold value is determined based on the ink density of the black ink by referring to the correspondence data.

9. A cleaning mechanism that cleans, with a cleaning liquid, a conveyor belt that conveys a medium on which an image is recorded by ejecting a pigment ink including a black ink and an ink other than the black ink, The cleaning mechanism includes: a storage section for storing a cleaning liquid; a first detection unit that detects an ink concentration of the black ink contained in the cleaning liquid stored in the storage unit; a second detection unit that detects an ink concentration of the pigment ink contained in the cleaning liquid stored in the storage unit; A cleaning control unit, the second detection unit detects the ink concentration of the pigment ink by receiving light scattered by the cleaning liquid; The cleaning control unit is determining a threshold value based on the ink density of the black ink detected by the first detection unit; a cleaning mechanism that discharges cleaning liquid from the storage portion when the ink concentration of the pigment ink detected by the second detection portion is equal to or greater than the threshold value.

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