Liquid discharge apparatus and control method of liquid discharge apparatus

Abstract

A liquid ejecting apparatus and a control method of the liquid ejecting apparatus, the liquid ejecting apparatus including a conveyance belt that conveys a medium, an ejecting section that ejects liquid toward the medium conveyed by the conveyance belt, a cleaning mechanism that cleans the conveyance belt, and a control section that controls the cleaning mechanism. The cleaning mechanism includes a mesh that abuts against the conveyance belt to wipe the liquid on the conveyance belt, and a drive section that changes a wiping surface of the mesh that abuts against the conveyance belt. The control section performs a first operation of changing the wiping surface of the mesh that abuts against the conveyance belt a predetermined number of times (M3) during a cleaning period in which the conveyance belt is cleaned.

Description

Liquid ejection device and control method of liquid ejection device Technical Field

[0001] The present invention relates to a liquid ejection device having an ejection section for ejecting liquids such as ink to a medium, and a control method for the liquid ejection device. Background Technology

[0002] For example, Patent Document 1 discloses a printing apparatus (an example of a liquid ejection apparatus) having a conveyor belt for conveying a medium and an ejection section for ejecting liquids such as ink toward the medium.

[0003] This recording device includes a belt cleaner for removing ink adhering to the conveyor belt. The belt cleaner includes a cleaning scraper that scrapes off the ink adhering to the belt and a cleaning screen that wipes away any remaining ink after scraping. The cleaning screen is positioned downstream of the cleaning scraper in the belt rotation direction. In the recording device, the cleaning screen is driven to rotate a predetermined amount, making the screen contact surface with the belt a new surface. Furthermore, the cleaning screen is driven in a timely manner by a screen drive motor, thereby capturing residual ink and cleaning fluid on one side of the screen. The screen drive motor is driven when a screen drive signal is input from the control unit, and this rotation causes the roller on the winding side of the screen to rotate. Thus, a predetermined amount of screen is wound up, making the contact surface with the belt a new surface. This discloses a structure that allows for the continuous delivery of a new screen contact surface to the belt surface due to the appropriate delivery of the cleaning screen by the screen drive motor.

[0004] Patent Document 1: Japanese Patent Application Publication No. 2005-169968

[0005] To extend the lifespan of cleaning mechanisms such as cleaners, increasing the overall length of the cleaning net is considered. However, this raises the risk of increasing the size of the cleaning mechanism itself. On the other hand, shortening the overall length of the net reduces its lifespan, thus increasing the frequency of net replacement and consequently increasing the burden on users or service personnel. In other words, conventional technologies have resulted in larger devices and higher replacement frequencies, and the goal is to extend the lifespan of the net. Summary of the Invention

[0006] A liquid ejection device for solving the above-mentioned problems includes: a conveyor belt for conveying a medium; an ejection unit for ejecting liquid onto the medium conveyed by the conveyor belt; a cleaning mechanism for cleaning the conveyor belt; and a control unit for controlling the cleaning mechanism, the cleaning mechanism including: a net that abuts against the conveyor belt and wipes the liquid on the conveyor belt; and a drive unit for changing the wiping surface of the net that abuts against the conveyor belt, the control unit performing a first action of changing the wiping surface of the net that abuts against the conveyor belt a predetermined number of times during the cleaning period of the conveyor belt.

[0007] In a control method for a liquid ejection device that solves the above-mentioned problems, the liquid ejection device includes: a conveyor belt for conveying a medium; an ejection section for ejecting liquid onto the medium conveyed by the conveyor belt; a net for contacting the conveyor belt and wiping the liquid on the conveyor belt; and a drive section for changing the wiping surface of the net that is contacted by the conveyor belt. The control method includes a first step of changing the wiping surface of the net that is contacted by the conveyor belt, and the first step is performed a predetermined number of times during the cleaning period of the conveyor belt. Attached Figure Description

[0008] Figure 1 is a schematic front sectional view showing the liquid ejection device in the embodiment.

[0009] Figure 2 is a schematic front view showing the cleaning facility.

[0010] Figure 3 is a schematic side view showing the cleaning mechanism.

[0011] Figure 4 is a schematic front sectional view showing the cleaning mechanism and the conveyor belt mechanism configured in the retracted position.

[0012] Figure 5 is a schematic front sectional view showing the cleaning mechanism and conveyor belt mechanism configured in the cleaning position.

[0013] Figure 6 is a schematic rear view showing the inspection unit in the cleaning mechanism.

[0014] Figure 7 is a schematic perspective view showing the detection unit.

[0015] Figure 8 is a block diagram showing the electrical structure of the liquid ejection device.

[0016] Figure 9 is a schematic diagram showing the first reference data.

[0017] Figure 10 is a schematic diagram showing the second reference data.

[0018] Figure 11 is a schematic diagram showing the third reference data.

[0019] Figure 12 is a schematic front view illustrating the sequence of the first cleaning action.

[0020] Figure 13 is a schematic front view illustrating the sequence of the second cleaning action.

[0021] Figure 14 is a flowchart illustrating the cleaning control routine.

[0022] Explanation of reference numerals in the attached figures

[0023] 11. Liquid ejection device; 12. Device body; 13. Stacker; 14. Printing section; 15. Control section; 16. Conveying device; 17. Medium; 19. Ejection section; 19A. Nozzle surface; 20. Nozzle; 21. Medium loading section; 22. Feeding section; 23. Conveying section; 24. Conveying roller pair; 26. Paper feeding roller pair; 27. Conveyor belt; 28. Roller; 29. ​​Discharge roller pair; 30. Conveyor belt mechanism; 31. Feed motor; 32. Pick-up roller; 33. Feed roller; 34. Separating roller; 36. Conveying path; 37. Tilting path; 38. Baffle; 40. Conveying surface; 41. First detection section; 42. Second detection section; 45. Guide roller; 46. 47. Receiving part; 51. Spring; 52. Support frame; 53. Gear; 54. Discharge roller; 55. Guide component; 56. Electrostatic brush; 57. Cam mechanism; 58. Spring; 59. Rotating shaft; 60. Rod component; 61. Cleaning mechanism; 62. Rotating shaft; 62. Support frame; 62A. Frame part; 63. Cleaning part; 64. Drive part; 65. Power transmission mechanism; 65G. Gear mechanism; 66. Net; 67. Wiping part; 67A. Wiping surface; 68. Spring; 69. Cam motor; 70. Cam component; 70A. Engaging surface; 71. Engaged surface; 72. Worm gear; 73. Gear; 74. Gear; 75. Gear; 76. Drive roller; 7 6A. Rotating shaft; 77. First guide roller; 78. Second guide roller; 79. Guide rod; 80. Spring; 81. Position sensor; 82. Pressing roller; 83. Detection unit; 84. Detected part; 84A. Disc; 84B. Detected part; 84C. Through hole; 85. Sensor; 85A. Light-emitting part; 85B. Light-receiving part; 87. Wiper; 91. Operation unit; 92. Display unit; 93. Medium width sensor; 94. Temperature sensor; 95. Humidity sensor; 96. Conveyor motor; 97. Belt motor; 98. Guide motor; 100. Computer; 101. First counter; 102. Second counter; 103. Third counter; 1 04. Ejection Control Unit; 105. Abnormal Detection Unit; 106. Cleaning Control Unit; 107. Storage Unit; 108. Calculation Unit; CP. Cleaning Position; RP. Retreat Position; WD. Conveying Direction; TN. Cumulative Number of Times; TM. Cumulative Number of Sheets; M1. Preset Number of Times; M2. Preset Number of Times After Correction; M3. Preset Number of Times After Correction; V1. First Speed; V2. Second Speed; A. Correction Coefficient; N. Number of Times the Net is Conveyed (Number of Times the Net is Driven Intermittently); m1. First Count; m2. Second Count; TM1. First Sheet Count; TM2. Second Sheet Count; Y. Width Direction; Dc. Conveying Direction; Z. Vertical Direction; BD. Rotation Direction; WD. Conveying Direction. Detailed Implementation

[0024] Hereinafter, embodiments of the liquid ejection device will be described with reference to the accompanying drawings. For example, the liquid ejection device of this embodiment is an inkjet printer that ejects ink, an example of a liquid, onto a medium such as paper for printing. In FIG1, the liquid ejection device 11 is placed on a horizontal plane, with the direction of gravity shown by the Z-axis and the directions along the horizontal plane shown by the X-axis and Y-axis. The X-axis, Y-axis, and Z-axis are orthogonal to each other. In the following description, since the direction along the Y-axis is the width direction of the medium 17, it is also referred to as the width direction Y. The direction along the Z-axis is the direction parallel to gravity, and is therefore also referred to as the vertical direction Z.

[0025] Structure of liquid ejection device 11

[0026] As shown in Figure 1, the liquid ejection device 11 may also include a stacker 13, a printing unit 14, a control unit 15, and a conveying device 16 within the main body 12 of the device.

[0027] The various structures of the liquid ejection device 11 are housed within the device body 12. Specifically, the device body 12 houses the printing unit 14, the control unit 15, and the conveying device 16.

[0028] Stacker 13 accepts media 17 conveyed by conveyor 16. Stacker 13 is capable of loading multiple printed media 17.

[0029] The printing unit 14 may also have an ejection section 19. Multiple nozzles 20 open at the ejection section 19. The printing unit 14 may also be configured such that the ejection section 19 is inclined relative to a horizontal plane. The printing unit 14 prints on the conveyed medium 17 by ejecting liquid from the nozzles 20. In this embodiment, the printing unit 14 is a line printing method for printing on the conveyed medium 17. Alternatively, the printing unit 14 may be a serial printing method that includes a carriage (not shown) supporting the ejection section 19, and prints on the medium 17 by ejecting liquid from the nozzles 20 midway through the movement of the ejection section 19 along the width direction Y.

[0030] The control unit 15 uniformly controls the driving of each mechanism in the liquid ejection device 11 and controls the various actions performed by the liquid ejection device 11.

[0031] The control unit 15 can be configured as a circuit including the following structures: α: one or more processors that execute various processes according to a computer program; β: one or more dedicated hardware circuits that execute at least a portion of the various processes; or γ: a combination thereof. For example, the hardware circuit is an application-specific integrated circuit. The processor includes a CPU and memories such as RAM and ROM, which store program code or instructions configured to cause the CPU to execute processes. Memory, i.e., computer-readable media, includes all readable media that can be accessed by a general-purpose or special-purpose computer.

[0032] Structure of conveying device 16

[0033] The conveying device 16 includes a media loading section 21, a feeding section 22, and a conveying section 23. The conveying device 16 may also include multiple media loading sections 21. In this case, the conveying device 16 may also include the same number of feeding sections 22 as the media loading sections 21. The conveying section 23 may also include a pair of conveying rollers 24, a pair of paper feeding rollers 26, a conveyor belt mechanism 30, and a pair of discharge rollers 29. The conveyor belt mechanism 30 may also include a conveyor belt 27 and a pair of rollers 28. Thus, the liquid ejection device 11 includes a conveyor belt 27 for conveying the medium 17 and an ejection section 19 for ejecting liquid onto the medium 17 conveyed by the conveyor belt 27. Furthermore, the liquid ejection device 11 of this embodiment includes a cleaning mechanism 60 for cleaning the conveyor belt 27. The control unit 15 controls the cleaning mechanism 60.

[0034] The feed unit 22 feeds the medium 17 contained in the medium placement unit 21 one sheet at a time from the corresponding medium placement unit 21 to the transport path 36. The feed unit 22 may also include a feed motor 31, a pick-up roller 32, a feed roller 33, and a separation roller 34.

[0035] The conveyor roller pair 24, the paper feed roller pair 26, and the discharge roller pair 29 each include a roller that contacts the surface of the medium 17 and a roller that contacts the back side of the medium 17. Alternatively, one roller may be a drive roller that is driven to rotate, and the other a driven roller that rotates passively.

[0036] In Figure 1, the transport path 36 and the reversing path 37 for transporting the medium 17 are shown by a dashed line. The transport path 36 connects the medium carrier 21 and the stacker 13. The reversing path 37 connects the transport path 36 downstream of the printing section 14 and the transport path 36 upstream of the printing section 14. The reversing path 37 is used to return the medium 17 that has been printed on only one side to the upstream position of the printing section 14 when both sides of the medium 17 have been printed. The transport device 16 may also include a baffle 38 for switching the transport path of the medium 17.

[0037] Alternatively, the medium placement section 21 can accommodate multiple media 17 in a stacked state. Multiple media 17 are placed on the medium placement section 21. "Placed" means placed on it, and can be moved by applying an external force.

[0038] The conveyor roller pair 24 conveys the medium 17 fed from the feed roller 33. The conveyor roller pair 24 conveys the medium 17 by rotating in a state that clamps the medium 17. One of the two rollers constituting the conveyor roller pair 24 can also be a toothed roller. If the roller that contacts the printed surface of the single-sided printed medium 17 is a toothed roller, the reduction in print quality can be suppressed.

[0039] The conveying device 16 may also include multiple paper feed roller pairs 26. The multiple paper feed roller pairs 26 may also be arranged in the conveying path 36 and the reversing path 37. The paper feed roller pairs 26 convey the medium 17 along the conveying path 36 or the reversing path 37 by rotating in a state of clamping the medium 17.

[0040] The conveyor belt 27 can also convey the medium 17 conveyed from the conveyor roller pair 24. The conveyor belt 27 is a loop belt. The conveyor belt 27 is mounted on a pair of rollers 28. The conveyor belt 27 travels around the pair of rollers 28 as one roller 28 rotates. The conveyor belt 27 has a conveying surface 40 for conveying the medium 17. The conveying surface 40 is a plane on the outer peripheral surface of the conveyor belt 27 that supports the medium 17, for example, by electrostatic adsorption. The conveyor belt 27 can also be configured such that the conveying surface 40 is parallel to the nozzle surface 19A of the ejector section 19. The conveyor belt 27 supports the portion of the medium 17 that has been printed by the printing section 14. The conveyor belt 27 conveys the medium 17 in the conveying direction Dc by traveling around it in a state of supporting the medium 17. The conveying direction Dc is the direction along the conveying path 36, which is the direction from the medium placement section 21 toward the stacker 13.

[0041] The discharge roller pair 29 can also be located at the downstream end of the conveying path 36. The discharge roller pair 29 discharges the printed medium 17 to the stacker 13 by rotating in a state that clamps the medium 17.

[0042] The feed motor 31 rotates the pickup roller 32. The pickup roller 32 feeds out the medium 17 placed at the top of the medium placement section 21 one sheet at a time.

[0043] The feed roller 33 contacts the upper surface of the medium 17 delivered by the pick-up roller 32. That is, when multiple media 17 are conveyed in an overlapping manner by the pick-up roller 32, the feed roller 33 contacts the uppermost medium 17. The feed roller 33 conveys the uppermost medium 17 in the conveying direction Dc.

[0044] The separating roller 34 holds the medium 17 between the separating roller 34 and the feed roller 33. The separating roller 34 is a driven roller capable of rotating in both directions. Therefore, during overlapping conveying, the separating roller 34 prevents the lower medium 17 from being conveyed out along the conveying direction Dc.

[0045] The liquid ejection device 11 has a first detection unit 41 and a second detection unit 42 on both sides of the ejection section 19 in the conveying direction Dc, which are capable of detecting the medium 17. The first detection unit 41 detects the medium 17 at a position upstream of the ejection section 19 in the conveying direction Dc. The second detection unit 42 detects the medium 17 at a position downstream of the ejection section 19 in the conveying direction Dc.

[0046] The control unit 15 identifies the position of the medium 17 on the transport path 36 based on the detection signals from the first detection unit 41 and the second detection unit 42. Additionally, the control unit 15 detects a jam of the medium 17 on the transport surface 40 of the conveyor belt 27 based on the signals from the first detection unit 41 and the second detection unit 42. After the first detection unit 41 detects the medium 17, the control unit 15 detects a jam of the medium 17 on the transport surface 40, regardless of whether the predetermined transport volume has ended, and without receiving a detection signal from the second detection unit 42 indicating that the medium 17 has been detected.

[0047] Structure of conveyor belt mechanism 30 and cleaning mechanism 60

[0048] Next, referring to Figure 2, the detailed structure of the conveyor belt mechanism 30 and the cleaning mechanism 60 will be described.

[0049] As shown in Figure 2, the cleaning mechanism 60 is positioned opposite the ejector section 19 to the conveyor belt 27. The cleaning mechanism 60 cleans the surface of the conveyor belt 27 from the side opposite the conveyor surface 40. When a paper jam occurs, the ejector section 19 ejects liquid without the medium 17, and the cleaning mechanism 60 removes any ink or other liquid adhering to the conveyor belt 27.

[0050] If a paper jam of medium 17 is detected on the conveyor surface 40, the control unit 15 causes the cleaning mechanism 60 to clean the conveyor belt 27. Specifically, if a paper jam of medium 17 is detected, the control unit 15 causes the display unit 92 (see Figure 8) to display a message including information indicating a paper jam and a request to clear the jam. The user who reads the message opens the cover of the device body 12 (not shown) to remove the jammed medium 17. The user who has cleared the jam notifies the liquid dispensing device 11 that the jam has been cleared by clicking "OK" on the operation unit 91 (see Figure 8). If the control unit 15 receives notification of the paper jam clearance from the operation unit 91, it causes the cleaning mechanism 60 to clean the conveyor belt 27.

[0051] Detailed structure of conveyor belt mechanism 30

[0052] Next, referring to Figures 2 to 4, the structures of the conveyor belt mechanism 30 and the cleaning mechanism 60 will be described in detail. First, the detailed structure of the conveyor belt mechanism 30 will be described with reference to Figure 2. As shown in Figure 2, the conveyor belt mechanism 30 includes: an endless conveyor belt 27, a pair of rollers 28, a support frame 51 supporting the pair of rollers 28 so that they can rotate, and a gear 52 coaxially disposed with one of the rollers 28. The pair of rollers 28 are supported on the support frame 51 in a state where forces are applied in a separating direction. Therefore, a fixed tension is applied to the conveyor belt 27 by the force acting on the separating direction of the pair of rollers 28.

[0053] Near the downstream end of the conveyor belt 27, there is a guide member 54 that guides the medium 17 on the conveyor surface 40 of the conveyor belt 27 toward the discharge roller 53, and a de-energizing brush 55 that de-energizes the conveyor belt 27. The de-energizing brush 55 is configured to be able to move by a cam mechanism 56 (not shown) to a working position close to or in contact with the conveyor belt 27 as shown in FIG2, and a retracted position separated from the conveyor belt 27.

[0054] The cam mechanism 56 includes a lever member 59 that applies force in one direction about a rotation axis 58 by means of a spring 57. The spring 57 applies force to the lever member 59 in the direction that positions the electrostatic precipitator 55 in the disengaged position. The lever member 59 rotates in the opposite direction to the force applied by the spring 57 via a drive unit (not shown), thereby moving the electrostatic precipitator 55 from the disengaged position to the engaged position. Furthermore, one of the rollers 28 rotates by power transmitted via a belt motor 97 (see Figure 8) which serves as the drive source, through a gear 52.

[0055] Additionally, a guide roller 45, shown by the double-dotted line in Figure 2, is positioned upstream of the conveying surface 40 of the conveyor belt 27 in the conveying direction Dc. The guide roller 45 is configured to move between a working position abutting the conveyor surface 40 and a separation position separated from the conveyor surface 40, powered by a guide motor 98 (see Figure 8). Furthermore, since the guide roller 45 moves in conjunction with the electrostatic eliminator brush 55, the guide motor 98 can also function as a drive unit for the electrostatic eliminator brush 55.

[0056] Detailed structure of cleaning unit 60

[0057] Next, the detailed structure of the cleaning mechanism 60 will be described with reference to Figures 2 and 3. The cleaning mechanism 60 includes a support frame 62 that can rotate within a predetermined angle range around a rotation axis 61. A cleaning unit 63, a drive unit 64, and a power transmission mechanism 65 are assembled on the support frame 62.

[0058] The cleaning section 63 is a section with a cleaning net 66. The net 66 is wound up according to a predetermined circulation path described later. A portion of the net 66 is formed as a wiping section 67 protruding toward the conveyor belt 27, with the surface opposite to the conveyor belt 27 and the conveying surface 40. The net 66 is intermittently conveyed (intermittent drive) by a driving force transmitted from the drive section 64 via the power transmission mechanism 65. With each intermittent conveying of the net 66, the portion of the net 66 in the wiping section 67 is changed from a net 66 contaminated with liquids such as ink to a new net 66. That is, with each intermittent conveying of the net 66, the wiping surface 67A of the wiping section 67 is changed to the surface of the new net 66.

[0059] Thus, the cleaning mechanism 60 includes: a net 66 that abuts against the conveyor belt 27 to wipe away liquid on the conveyor belt 27; and a drive unit 64 for intermittent driving, which changes the portion of the net 66 that abuts against the conveyor belt 27 to a new wiping surface 67A. The control unit 15 performs a first action of changing the wiping surface 67A of the net 66 that abuts against the conveyor belt 27 a predetermined number of times during the cleaning period of the cleaning conveyor belt 27.

[0060] The force of a spring 68, one end of which is hooked near the end opposite to the rotating shaft 61, applies force to the support frame 62, causing the support frame 62 to rotate toward the conveyor belt 27. For example, the spring 68 is a tension spring made of helical spring, the other end of which is hooked to a predetermined part of the support frame 51 or the main frame (not shown) that constitutes the conveyor belt mechanism 30. In this way, the force of the spring 68 applies force to the cleaning mechanism 60 in the direction that brings the wiping part 67 toward the conveyor belt 27.

[0061] The cleaning mechanism 60 includes a mesh 66, a drive unit 64 for rotating the mesh 66, and gears 72-75 (described later). Furthermore, the cleaning mechanism 60 may also include a wiper 87 (scraper) as shown by the double-dotted line in FIG2. The wiper 87 is positioned upstream of the wiping section 67 of the mesh 66 in the rotation direction BD of the conveyor belt 27. During cleaning, the wiper 87 comes into contact with the conveyor belt 27 and scrapes off the liquid on the conveyor belt 27. The cleaning mechanism 60 may also include a wiper 87 and a drive unit for the wiper 87 (not shown). Alternatively, the wiper 87 may be positioned downstream of the wiping section 67 in the rotation direction BD of the conveyor belt 27 during cleaning.

[0062] The cleaning mechanism 60 includes a drive source, namely a cam motor 69 (see Figure 8), capable of rotating the support frame 62 around a rotation axis 61. A cam member 70, driven by the cam motor 69, is disposed near the rotating end portion of the support frame 62. The support frame 62 has a engaging surface 71 at its rotating end portion (lower end) that engages with the cam member 70. For example, the cam member 70 is a rotating cam. The cam member 70 has a rotation axis 70B and an engaging surface 70A formed at the rotating end portion.

[0063] The cam member 70 rotates between a non-engaged position, as shown in Figures 2 and 5, where its engagement surface 70A is separated from the engaged surface 71, and an engaged position, as shown in Figure 4, where its engagement surface 70A abuts against the engaged surface 71. Specifically, when the cam member 70 is in the non-engaged position shown in Figures 2 and 5, the engagement surface 70A of the cam member 70 is separated from the engaged surface 71, causing the support frame 62 to rotate clockwise as shown in Figure 2 under the force of the spring 68. Thus, the cleaning mechanism 60 is positioned at the cleaning position CP, where the wiping part 67 abuts against the surface of the conveyor belt 27. On the other hand, when the cam member 70 is in the engaged position shown in Figure 4, the engaged surface 71 is pressed in by the engagement surface 70A of the cam member 70, causing the support frame 62 to rotate counterclockwise from the cleaning position CP as shown in Figure 2. Thus, the cleaning mechanism 60 is positioned at the retracted position RP, where the wiping part 67 is separated from the conveyor belt 27.

[0064] Next, referring to Figures 2 and 3, the detailed structure of the cleaning unit 63 (including the net 66), the drive unit 64, and the power transmission mechanism 65 will be described.

[0065] The drive unit 64 is, for example, an electric motor. The driving force of the drive unit 64 is transmitted to the cleaning unit 63 via the power transmission mechanism 65. The cleaning unit 63 intermittently conveys the net 66 in the conveying direction WD (see Figure 5) by the driving force of the drive unit 64. The cleaning unit 63 is driven in such a way that the wiping surface 67A of the wiping unit 67 is changed from the cleaned net 66 that has been contaminated by liquids such as ink to the new net 66 before cleaning.

[0066] The power transmission mechanism 65 can also be, for example, the gear mechanism 65G shown in FIG. 2. The gear mechanism 65G includes multiple gears 72 to 75. That is, the gear mechanism 65G in the example shown in FIG. 2 and FIG. 3 includes a worm gear 72 that rotates by the driving force of the drive unit 64 and gears 73 to 75. The two gears 73 and 74 are, for example, composed of two-stage gears. The worm gear 72 meshes with the large gear 73A of the gear 73. The small gear 73B of the gear 73 (refer to FIG. 3) meshes with the large gear 74A of the gear 74. The small gear 74B of the gear 74 (refer to FIG. 3) meshes with the gear 75.

[0067] Gear 75 is a drive gear, fixed to the shaft end of one of the plurality of rollers 76-78 (see also Figure 4) on which the mesh 66 is mounted, namely the drive roller 76. Furthermore, the mesh 66 is guided to the wiping section 67 via a guide rod 79 extending in the width direction Y. Additionally, as shown in Figure 2, a spring 80 is provided in the support frame 62 to apply tension to the mesh 66 mounted on the plurality of rollers 76-78.

[0068] Based on the above structure, the gear mechanism 65G has a large reduction ratio. Specifically, if the worm gear 72 rotates multiple times, the gear 73 rotates one revolution; if the gear 73 rotates multiple times, the gear 74 rotates one revolution; and so on, if the gear 74 rotates multiple times, the gear 75 rotates one revolution. Therefore, for example, the reduction ratio of the gear mechanism 65G is set to a predetermined value within the range of 10 to 30. Furthermore, as shown in FIG2, a position sensor 81 for detecting whether the cleaning mechanism 60 is in the cleaning position CP is installed on the support frame 51 constituting the conveyor belt mechanism 30.

[0069] Additionally, as shown in FIG3, a plurality of pressing rollers 82 are arranged at intervals along the width direction Y in the frame portion 62A. The plurality of pressing rollers 82 clamp the mesh 66 between themselves and the drive roller 76 (see FIG4) with a predetermined pressing force. Furthermore, in the cleaning mechanism 60 shown in FIG3, a detection unit 83 is arranged on the surface opposite to the surface where the drive unit 64 and the power transmission mechanism 65 are assembled in the width direction Y, in the area where the mesh 66 is clamped. The detection unit 83 detects the amount of mesh 66 conveyed by detecting the rotation of the drive roller 76. The detection unit 83 has a detected part 84 and a sensor 85.

[0070] Structure of cleaning section 63

[0071] Next, the structure of the cleaning unit 63 will be described with reference to Figures 4 and 5. Figure 4 shows the cleaning mechanism 60 in the retracted position RP. Figure 5 shows the cleaning mechanism 60 in the cleaning position CP.

[0072] First, the position switching operation of the cleaning mechanism 60 between the retracted position RP and the cleaning position CP will be explained. As shown in Figure 4, if the cam member 70 rotates to the first rotational posture shown in the figure, during this process, the engaging surface 70A abuts against the engaged surface 71, overcoming the force of the spring 68 and pressing it in a counterclockwise direction. As a result, the cleaning mechanism 60 is positioned in the retracted position RP. In this retracted position RP, the wiping part 67 is separated from the conveyor belt 27. In addition, the position sensor 81 is disconnected.

[0073] On the other hand, as shown in Figure 5, if the cam component 70 rotates to the second rotational posture shown in the figure, during this process, the cleaning mechanism 60 rotates clockwise under the force of the spring 68 until the wiping part 67 contacts the conveyor belt 27. As a result, the cleaning mechanism 60 is positioned at the cleaning position CP. At this cleaning position CP, the position sensor 81 is activated.

[0074] As shown in Figures 4 and 5, the cleaning section 63 has a ring-shaped mesh 66, meaning the mesh 66 is endless. The mesh 66 is mounted on the outer periphery of multiple rollers 76-78. Specifically, the endless mesh 66 is mounted on the drive roller 76, the first guide roller 77, and the second guide roller 78. The first guide roller 77 is positioned to slightly protrude from the support frame 62 toward the conveyor belt 27. The wiping section 67 is formed by winding the mesh 66 around a portion of the outer peripheral surface of the first guide roller 77. Furthermore, the mesh 66 is wound at a relatively large angle relative to the outer peripheral surface of the first guide roller 77 via a guide rod 79 located between the drive roller 76 and the first guide roller 77. Additionally, the second guide roller 78 is pulled in a direction separating from the drive roller 76 by the spring 80 shown in Figure 3, thereby applying a predetermined tension to the mesh 66.

[0075] For example, the drive roller 76 is a rubber roller. Therefore, the net 66 is difficult to slide relative to the outer peripheral surface of the drive roller 76. Furthermore, the net 66 is clamped between the drive roller 76 and the pressing roller 82 with a predetermined clamping pressure. Therefore, the net 66 is even more difficult to slide relative to the drive roller 76. Thus, if the rotation amount of the drive unit 64 is controlled by the control unit 15 (see Figure 1), the intermittent conveying amount of the net 66 is also accurately controlled.

[0076] The drive roller 76 is rotated in a predetermined direction by the driving force from the drive unit 64, causing the net 66 to rotate in a fixed conveying direction WD. This conveying direction WD is the same as the direction of the force received by the wiping unit 67 from the conveyor belt 27 during cleaning. During cleaning, the wiping unit 67, which abuts against the conveyor belt 27, receives a force in the rotational direction BD of the conveyor belt 27. The conveying direction WD is set such that the direction of the force received by the wiping unit 67 from the conveyor belt 27 in the rotational direction BD during cleaning is the same as the conveying direction of the net 66 in the wiping unit 67.

[0077] As described above, the cleaning mechanism 60 includes gears 72-75 that transmit power from the drive unit 64. The mesh 66 is structured such that it receives power from the drive unit 64 via gears 72-75 and is conveyed, thereby altering the wiping surface 67A of the wiping section 67. The conveying direction WD of the mesh 66 is the same as the direction in which the mesh 66 receives frictional force from the rotating conveyor belt 27 while in contact with the conveyor belt 27. In other words, the conveying direction WD of the mesh 66 is the same as the direction of the frictional force received by the portion of the mesh 66 that abuts against the conveyor belt 27 during the cleaning operation. Therefore, the direction of the force (frictional force) received by the wiping section 67 from the conveyor belt 27 during cleaning is consistent with the direction of the gaps between the teeth of the gears 72-75. Therefore, even if the wiping section 67 wipes the conveyor belt 27 and then conveys the net 66 in the conveying direction WD, since the conveying direction WD is the direction in which the gaps between the teeth of the gears 72 to 75 are filled during the cleaning action, it is difficult to produce a deviation in the conveying amount of the net 66 caused by the gaps.

[0078] In this embodiment, the conveying amount of the net 66 is a predetermined value within the range of 0.5 mm to 5 mm in each conveying. The predetermined value is, for example, approximately 1 mm. By conveying the net 66 with this very short conveying amount, the net 66 that has been used to wipe away the ink-contaminated wiping surface 67A is replaced with a new net 66. Here, assuming that the conveying direction WD is opposite to the direction of the force received from the conveyor belt 27, since a portion of the driving amount of the drive unit 64 is used to fill the backlash of the gears 72 to 75, the conveying amount of the net 66 in the distribution of the driving amount of the drive unit 64 will at most produce a deviation in the amount of backlash reduction. In this case, it is possible that a portion of the contaminated wiping surface 67A will not be replaced with a new net 66. Alternatively, in order to completely replace the new wiping surface 67A with the net 66, an estimated amount of backlash is generated, resulting in a greater waste in the amount of conveying each time. Furthermore, the conveying amount of the net 66 in one conveying may exceed 5 mm.

[0079] In this embodiment, the conveyor belt 27 is cleaned (sweeped) by rotating it in the rotation direction BD while the wiping part 67 is in contact with the surface of the conveyor belt 27. After a predetermined amount of rotation from the start of cleaning until the end of the conveyor belt 27, the wiping part 67 is contaminated by the ink wiped off the conveyor belt 27. When the wiping part 67 is considered to be contaminated to a certain degree or more, the control unit 15 performs intermittent conveying of one conveying amount of net 66, thereby changing the wiping surface 67A to a new net 66.

[0080] The timing of intermittent conveying of the net 66 during cleaning can be managed based on the rotation amount of the conveyor belt 27 or the rotation time of the conveyor belt 27. Furthermore, the timing of intermittent conveying of the net 66 during cleaning can be changed based on the estimated amount of ink adhering to the conveyor belt 27. Moreover, the rotational speed of the conveyor belt 27 during cleaning can be changed based on the estimated amount of ink adhering to the conveyor belt 27. These controls are performed by the control unit 15 to drive the drive unit 64 and the conveyor belt 27 during cleaning. Details regarding the control functions of the control unit 15 will be described later.

[0081] Furthermore, as shown in Figure 5, in the conveyor belt mechanism 30, when the conveyor belt 27 is sandwiched between the wiping part 67 and the conveyor belt 27, the receiving part 46 is in a state where the conveyor belt 27 is pressed outward (towards the wiping part 67) by the spring 47. While the wiping part 67 is in contact with the conveyor belt 27, it presses down on the conveyor belt 27, but the receiving part 46 receives this pressing force from the opposite side of the conveyor belt 27 due to the force of the spring 47. Therefore, a predetermined contact pressure can be ensured when the wiping part 67 contacts the surface of the conveyor belt 27.

[0082] The conveyor belt 27 is a waterproof belt. That is, a waterproof layer is formed on the surface of the conveyor belt 27 through a waterproofing process. Because the surface of the conveyor belt 27 is waterproof, ink stains can be easily removed from the conveyor belt 27. However, the conveyor belt 27 is not limited to being a waterproof belt.

[0083] About Net66

[0084] The mesh 66 is made of a material that absorbs liquids such as ink. For example, the mesh 66 can be made of cloth. Besides cloth, the mesh 66 can also be made of non-woven fabric, paper, porous synthetic resin materials, etc. The mesh 66 can also be made of an endless (ring-shaped) strip formed from a material that absorbs liquids. Here, the total length of the mesh 66 is set to the product of the frequency of paper jams occurring on the conveyor surface 40 (total estimated number of occurrences) and the average length of the mesh 66 consumed in one paper jam cleanup, plus a small margin.

[0085] About cardboard

[0086] Of the paper jams that occur on the conveying path 36 and the reversing path 37, the frequency of paper jams occurring on the conveying surface 40 of the conveyor belt 27 is very low. Here, the paper jam that occurs on the conveying surface 40 is referred to as the first paper jam, and is distinguished from other paper jams, which are referred to as the second paper jam. Although the medium 17 detected by the first detection unit 41 has been conveyed to a sufficient length, i.e., the predetermined conveying amount, until it is detected by the second detection unit 42, the second detection unit 42 fails to detect the medium 17, and thus detects it as the first paper jam.

[0087] Therefore, when the first paper jam occurs, there is a situation where the medium 17 is not present on the conveyor surface 40. In this state, if the ejector 19 ejects liquid from the nozzle 20, the ejected liquid falls onto the surface of the conveyor belt 27. That is, due to accidental ejection, the surface of the conveyor belt 27 is contaminated with ink or other liquids. If the user starts the next printing directly after the first paper jam is cleared while the conveyor belt 27 is contaminated with liquid, the ink or other liquids on the conveyor belt 27 will be transferred to the medium 17, resulting in the medium 17 being contaminated with ink or other liquids. In this case, since the printed medium 17 becomes a defective product, the user needs to clean the conveyor belt 27 and reprint.

[0088] In this embodiment, to reduce or eliminate such printing failures, the cleaning mechanism 60 cleans the conveyor belt 27 after the first paper jam inspection and before the next printing begins. Therefore, printing failures due to ink contamination of the conveyor belt 27 can be avoided in the next printing session starting after the first paper jam.

[0089] Structure of the detection unit 83

[0090] Next, referring to Figures 3, 6 and 7, the structure of the detection unit 83 for the conveying quantity of the detection network 66 will be described.

[0091] As shown in Figure 3, the cleaning mechanism 60 includes a detection unit 83 for detecting the rotation amount of the drive unit 64. The detection unit 83 includes a rotatable detection part 84 fixed to the end of the rotation shaft 76A of the drive roller 76, and a sensor 85 for detecting the detection part 84.

[0092] As shown in Figures 6 and 7, the detection unit 83 includes: a plurality of detection portions 84B, which are spaced apart in the circumferential direction of a disk 84A that rotates integrally with the rotation shaft 76A of the drive unit 64; and a sensor 85 that sequentially detects the plurality of detection portions 84B. The detection unit 84 includes a disk 84A and a plurality of detection portions 84B arranged intermittently in the circumferential direction at fixed intervals on the outer periphery of the disk 84A. As shown in Figure 7, the disk 84A has a through hole 84C in its central portion. The rotation shaft 76A of the drive roller 76 is inserted into the through hole 84C in a non-rotating state. The disk 84A is rotated by rotating the rotation shaft 76A. The plurality of detection portions 84B are bent at approximately a right angle from the outer periphery of the disk 84A in a direction parallel to the axis of the through hole 84C.

[0093] The sensor 85 includes, for example, a light-emitting part 85A and a light-receiving part 85B. The sensor 85 may also be configured as an optical circuit breaker. The light-emitting part 85A and the light-receiving part 85B constituting the sensor 85 are arranged opposite each other on both sides of the disk 84A in the radial direction that encloses the rotation trajectory of the detected part 84B.

[0094] As shown in Figure 7, the detection unit 84 has, for example, three or more detection units 84B. The number of detection units 84B can be three or more, or it can be four, five, six, or more. In the example shown in Figure 7, the detection unit 84 has eight detection units 84B. Here, if the number of detection units 84B in the detection unit 84 is set to M, the conveying amount of the mesh 66 can be detected with M times the resolution compared to the case where the number of detection units 84B is one. Because of this intermittent conveying structure of the mesh 66, the conveying amount per pass only needs to be the small amount required to change the mesh 66 of the wiping unit 67 to a new surface. Therefore, the detection unit 83 is configured to obtain the resolution required for detecting the small amount of conveying amount of the mesh 66 each time.

[0095] Electrical structure of liquid ejection device 11

[0096] Next, the electrical structure of the liquid ejection device 11 will be described with reference to FIG8.

[0097] As shown in Figure 8, the liquid ejection device 11 includes the aforementioned control unit 15. The control unit 15 inputs printing data PD. The control unit 15 drives and controls the printing mechanism 12A based on the printing data PD to print on the medium 17. The printing data PD includes printing instructions, printing condition information, and image data. The printing condition information includes the type and size of the medium, and the color / monochrome printing mode. The image data is dot data. The amount of ink ejected from the nozzles 20 of the ejection unit 19 is determined based on the dot information of the image data. The size of the ink droplets can also be divided into multiple stages. For example, the size of the ink droplets can be two sizes, three sizes (large, medium, small), or more than four sizes. When large ink droplets are ejected from all nozzles 20 of the ejection unit 19, the printing duty cycle is 100%. When the printing duty cycle is 100%, the amount of ink ejected is at its maximum. As the printing duty cycle decreases, the amount of ink ejected from the ejection unit 19 becomes less.

[0098] As an input system, the control unit 15 is electrically connected to an operation unit 91, a display unit 92, a first detection unit 41, a second detection unit 42, a medium width sensor 93, a temperature sensor 94, a humidity sensor 95, a position sensor 81, and a detection unit 83. The detection unit 83 includes an optical sensor 85.

[0099] As an output system, the control unit 15 is electrically connected to the ejection unit 19, the feed unit 22, the conveying unit 23, and the cleaning mechanism 60. Specifically, the control unit 15 is electrically connected to the feed motor 31 constituting the feed unit 22, the conveying motor 96 constituting the conveying unit 23, the belt motor 97, and the guide motor 98. Furthermore, the control unit 15 is electrically connected to the drive unit 64 constituting the cleaning mechanism 60 and the cam motor 69.

[0100] The control unit 15 includes a computer 100. The computer 100 includes a first counter 101, a second counter 102, and a third counter 103. Furthermore, the computer 100 includes an ejection control unit 104, an anomaly detection unit 105, a cleaning control unit 106, and a storage unit 107. The cleaning control unit 106 includes an arithmetic unit 108. Additionally, the storage unit 107 stores information such as a program PR, first reference data RD1, second reference data RD2, third reference data RD3, cumulative count TN, and cumulative sheet count TM. The program PR includes the cleaning control routine shown in the flowchart of FIG14.

[0101] The ejection control unit 104, the anomaly detection unit 105, and the cleaning control unit 106 can also be software constructed by executing program PR on computer 100, or hardware composed of electronic circuits such as ASIC, or a structure based on the cooperation of software and hardware. Furthermore, in this embodiment, at least a portion of the ejection control unit 104, the anomaly detection unit 105, and the cleaning control unit 106 includes software.

[0102] The first counter 101 counts the value indicating the position of the medium 17 on the transport path. For example, if the first detection unit 41 detects the end of the medium 17, the first counter 101 is reset, and then the number of input pulses or pulse edges from the rotary encoder (not shown) that detects the rotation of the transport motor 96 is counted. The count value of the first counter 101 indicates the position of the medium 17 on the transport path. The control unit 15 identifies the position of the medium 17 on the transport path based on the count value of the first counter 101.

[0103] The second counter 102 counts the cumulative number of sheets of medium 17. For example, the second counter 102 counts the cumulative number of sheets by counting the number of the back ends of medium 17 detected by the second detection unit 42.

[0104] The third counter 103 counts the cumulative number of intermittent deliveries of the web 66 performed by the cleaning mechanism 60. The total length WL, which is the length of one circumference of the web 66, is the length obtained by multiplying the intermittent delivery amount F, the estimated number of first paper jams J that may occur during the service life of the liquid ejection device 11, and the average number of intermittent web deliveries P for each first paper jam, plus a predetermined margin ΔL. That is, the total length WL of the web 66 is set as WL = F * J * P + ΔL. Thus, even if the liquid ejection device 11 reaches its service life, the count value of the third counter 103 will not reach a value equivalent to the total length of the web 66.

[0105] The ejection control unit 104 controls the ejection unit 19. Specifically, the ejection control unit 104 controls the ejection unit 19 based on the image data contained in the print data PD. The ejection control unit 104 controls the size (amount) of the droplets ejected from the nozzle 20 of the ejection unit 19 using a duty cycle value based on the pixel values ​​of the image data.

[0106] Computer 100 uses the duty cycle value or image data used by ejection control unit 104 in ejection control to calculate printing duty cycle value. Here, printing duty cycle value is equivalent to the amount of liquid ejected by ejection unit 19 per unit area of ​​medium 17. Furthermore, printing duty cycle value is also defined as the amount of liquid ejected by ejection unit 19 per unit time, i.e., the average ejection amount by ejection unit 19 per unit time, if the transport speed of medium 17 is set to a constant. For example, when the largest droplets are ejected from all nozzles 20 of ejection unit 19, the printing duty cycle value is set to 100%. The printing duty cycle value is proportional to the product of the number of nozzles 20 ejecting droplets and the size of the droplets ejected from each nozzle 20. Furthermore, printing duty cycle value is an example of information related to the amount of liquid ejected from ejection unit 19 toward medium 17.

[0107] The anomaly detection unit 105 detects anomalies such as paper jams caused by blockages in the transport path of the medium 17. Paper jams include first paper jams occurring on the conveyor belt 27. A first paper jam occurs when the medium 17, which should be on the conveyor belt 27, is blocked midway through transport to its intended position on the conveyor belt 27. Even though the medium 17 detected by the first detection unit 41 has been transported for a sufficient length (i.e., the predetermined transport quantity) until it is detected by the second detection unit 42, the second detection unit 42 fails to detect the medium 17, thus the anomaly detection unit 105 detects the first paper jam.

[0108] When the first paper jam occurs, even if the control unit 15 detects the abnormality and stops the ejection, because there was already an ordered amount before the stop, the ejection unit 19 sprays ink or other liquids onto the conveyor surface 40 of the conveyor belt 27, where there is no medium 17. Therefore, if the computer 100 receives an operation signal indicating that the first paper jam has been cleared, it instructs the cleaning mechanism 60 to clean the conveyor belt 27 contaminated with ink or other liquids.

[0109] The cleaning control unit 106 controls the cleaning mechanism 60. If the anomaly detection unit 105 detects a first paper jam, the cleaning control unit 106 causes the cleaning mechanism 60 to clean the conveyor belt 27. The cleaning control unit 106 controls the drive unit 64 and the cam motor 69 to cause the cleaning mechanism 60 to perform a series of cleaning actions. The cleaning control unit 106 is equipped with a calculation unit 108 for performing various calculations. Further details regarding the series of cleaning actions will be described later.

[0110] The control unit 15 acquires information related to the amount of liquid ejected from the ejector 19 toward the medium 17. Based on this information, the control unit 15 determines a predetermined number of times M1. Furthermore, when the amount of liquid is a first amount, the control unit 15 sets the predetermined number of times to a first number m1. In addition, when the amount of liquid is a second amount less than the first amount, the control unit 15 sets the predetermined number of times to a second number m2 less than the first number m1.

[0111] In this embodiment, the printing duty cycle value is used as information related to the amount of liquid ejected from the ejection section 19 toward the medium 17. The control unit 15 sets a predetermined number of times M1 based on the printing duty cycle value. Furthermore, as described above, the printing duty cycle value refers to the amount ejected per unit area of ​​the medium 17, or the amount ejected per unit time. When the printing duty cycle is a first printing duty cycle value, the control unit 15 sets the predetermined number of times M1 to a first number m1. Additionally, when the printing duty cycle is a second printing duty cycle value that ejects a second amount of liquid less than the first amount, the control unit 15 sets the predetermined number of times M1 to a second number m2 less than the first number m1.

[0112] The control unit 15 can also determine the predetermined number of times M1, which shows the number of times the web is transported corresponding to the printing duty cycle, based on the printing duty cycle value and the first reference data RD1 shown in FIG9.

[0113] Figure 9 shows the first reference data RD1, which is a table illustrating the correspondence between printing duty cycle values ​​and the number of halftone feeds (intermittent feeds). In the example shown in Figure 9, the number of halftone feeds is set to one when the printing duty cycle is 0%–10%, three when it is 11%–30%, six when it is 31%–60%, and ten when it is above 61%. Figure 9 is an example; the printing duty cycle values ​​can also be divided into other ranges, with other values ​​set as the number of halftone feeds within each range. As shown in Figure 9, the number of ranges in the first reference data RD1 is not limited to four stages; it can also be two stages, three stages, five stages, six stages, or more. For example, the printing duty cycle values ​​can be divided into ten stages in every 10% of the first reference data RD1, with the number of halftone feeds set sequentially from one to ten starting from the smaller range. Alternatively, for example, it can be divided into two stages: 0%–50% and 51%–100%, with the number of halftone feeds set sequentially from one to two starting from the smaller range.

[0114] Additionally, the control unit 15 can also acquire information related to at least one of humidity and temperature within the device body 12. The control unit 15 can also determine a predetermined number of times based on information related to at least one of humidity and temperature. In this embodiment, the predetermined number of times M1 set according to the printing duty cycle value is corrected based on at least one of humidity and temperature. The control unit 15 acquires temperature information from the temperature sensor 94 and humidity information from the humidity sensor 95. In this embodiment, the control unit 15 determines the predetermined number of times, for example, based on information related to humidity and temperature. Furthermore, the control unit 15 can also set a predetermined number of times based on information related to at least one of humidity and temperature, and correct that predetermined number of times based on the printing duty cycle value.

[0115] The control unit 15 can also determine a predetermined number M2, which shows the number of wire feeds corresponding to the combination of humidity and temperature, based on information related to humidity and temperature and referring to the second reference data RD2 shown in FIG10. In the example shown in FIG10, the number of wire feed corrections corresponding to the combination of humidity and temperature is set in the second reference data RD2. The control unit 15 determines the predetermined number M2 by correcting the predetermined number M1, which is determined based on the printing duty cycle value, with the number of wire feed corrections corresponding to the combination of humidity and temperature.

[0116] Furthermore, the control unit 15 acquires information related to the cumulative number of sheets TM of the medium conveyed by the conveyor belt 27. Based on this information, the control unit 15 determines the predetermined number of times. The predetermined number of times is greater when the cumulative number of sheets TM of the medium is a first number TM1 than when the cumulative number of sheets TM of the medium 17 is a second number TM2, which is less than the first number TM1. That is, when the cumulative number of sheets TM of the medium 17 is the first number TM1, the control unit 15 sets the predetermined number to a first number m1; when the cumulative number of sheets TM of the medium 17 is a second number TM2, which is less than the first number TM1, the control unit 15 sets the predetermined number to a second number m2, which is less than the first number m1. The control unit 15 acquires the information on the cumulative number of sheets TM used in determining the predetermined number of times from the count value of the second counter 102 or the storage unit 107.

[0117] Based on information related to the cumulative number of sheets TM of the medium, the control unit 15 obtains a correction coefficient A corresponding to the cumulative number of sheets TM by referring to the third reference data RD3 shown in FIG11. The control unit 15 determines the predetermined number of times M3 by multiplying the predetermined number of times M2, which is corrected according to the combination of humidity and temperature, by the correction coefficient A. In addition, the predetermined number of times M3 may also be determined based on at least one of the printing duty cycle, humidity, and temperature, and one or both of the cumulative number of sheets TM.

[0118] In addition, the control unit 15 rotates the conveyor belt 27 at a first speed V1 from the start of cleaning until a predetermined time, and then rotates the conveyor belt 27 at a second speed V2, which is faster than the first speed V1, after the predetermined time.

[0119] For example, the rotational speed of the conveyor belt 27 can be switched from low speed to high speed after one or two intermittent drives (intermittent conveying). Alternatively, for example, in the case of only one intermittent drive, the conveyor belt 27 can be rotated at a first speed V1 (low speed) for a predetermined time period during the single intermittent drive. Afterwards, the conveyor belt 27 can be rotated at a second speed V2 (high speed), which is faster than the first speed V1. Alternatively, for example, in the case of two intermittent drives, the conveyor belt 27 can be rotated at the first speed V1 for a first time period after the first intermittent drive. Then, the conveyor belt 27 can be rotated at the first speed V1 for a second time period after the second intermittent drive. In this case, the total time of the first and second times equals the predetermined time. Furthermore, the conveyor belt 27 can be rotated at the first speed V1 for these predetermined time periods from the start of cleaning, and then rotated at the second speed V2 (high speed) after the predetermined time.

[0120] The media width sensor 93 detects the width of the media 17. The control unit 15 acquires information related to the width of the media 17 based on the detection signal from the media width sensor 93. The control unit 15 determines whether the width of the media 17 actually being transported matches the media size specified by the printing condition information by detecting the width of the media 17. In addition, the control unit 15 detects the offset in the width direction Y of the media 17 based on the detection signal from the media width sensor 93, and adjusts the liquid ejection position in the width direction Y according to the position of the offset.

[0121] Furthermore, the control unit 15 can also determine the area in the width direction Y on the surface of the conveyor belt 27 where ink or other liquid is attached when the first paper jam occurs, based on information related to the width from the media width sensor 93. By determining the ink-attached area in the width direction Y, the amount of ink that the wiping unit 67 should wipe away can be estimated. Therefore, in addition to the printing duty cycle value, the control unit 15 can also determine the number of times the screen 66 is fed, i.e., the predetermined number of times M1, is fed, based on information about the width of the media 17 detected by the media width sensor 93, which is estimated to be an ink-attached area. Alternatively, instead of the width-related information from the media width sensor 93, the number of times the screen 66 is fed, i.e., the predetermined number of times M1, is fed, can be determined based on the width area determined according to the media size information included in the printing condition information.

[0122] effect

[0123] Next, the function of the liquid spraying device 11 will be explained. Referring to FIG14, the explanation will focus on the cleaning action of cleaning the conveyor belt 27 in the liquid spraying device 11.

[0124] Hereinafter, the computer 100 within the control unit 15 drives and controls the conveyor belt mechanism 30 and the cleaning mechanism 60 by executing the cleaning control routine program PR shown in the flowchart of FIG14. The cleaning control executed by the computer 100 will be described below.

[0125] First, in step S11, the computer 100 determines whether a paper jam is detected in the printing area. Although a predetermined conveying operation is performed after the first detection unit 41 detects the medium 17, if the medium 17 is not detected by the second detection unit 42, the control unit 15 identifies it as a paper jam caused by the medium 17 blocking the conveyor surface 40 of the conveyor belt 27, i.e., in the printing area. If a paper jam is detected in the printing area, the process proceeds to step S12; if no paper jam is detected in the printing area, the routine ends.

[0126] In the next step S12, the computer 100 acquires the printing duty cycle value. The computer 100 calculates the printing duty cycle value based on the image data in the print data PD. The printing duty cycle value is a value proportional to the amount of ink accidentally ejected toward the conveyor belt 27 when the first paper jam occurs. That is, the printing duty cycle value is used to estimate the amount of ink adhering to the conveyor belt 27, which is the object to be cleaned.

[0127] In step S13, the computer 100 determines the number of wire feeds as a predetermined number M1. Specifically, the computer 100 determines the predetermined number M1 corresponding to the printing duty cycle based on the printing duty cycle value and referring to the first reference data RD1. As shown in FIG9, for example, if the printing duty cycle value is within the range of 31% to 60%, the number of wire feeds is determined to be "six times".

[0128] In the next step S14, the computer 100 acquires temperature / humidity. That is, the computer 100 acquires temperature / humidity related information based on detection signals input from the temperature sensor 94 and the humidity sensor 95. This information indicates the temperature / humidity inside or around the device body 12. Temperature / humidity affects the viscosity of the ink adhered to the conveyor belt 27.

[0129] In step S15, the computer 100 corrects the network transport calibration to a predetermined number M2 corresponding to the temperature / humidity. Specifically, the computer 100 obtains the network transport calibration number corresponding to the temperature / humidity combination based on the temperature / humidity combination and referring to the second reference data RD2 shown in FIG10. Furthermore, the computer 100 determines the predetermined number M2 by correcting the previously determined predetermined number M1 with the network transport calibration number. As shown in FIG10, if the obtained temperature / humidity is, for example, within the range of "high temperature and high humidity" or "low temperature and low humidity," the network transport calibration number is "added twice," so the predetermined number M1 is increased by "2" to obtain the predetermined number M2 (=M1+2). Conversely, if the obtained temperature / humidity is, for example, within the range of "high temperature and low humidity," the network transport calibration number is "added four times," so the predetermined number M1 is increased by "4" to obtain the predetermined number M2 (=M1+4). Furthermore, if the obtained temperature / humidity is within the range of a combination of low temperature and high humidity, including room temperature, the predetermined number M1 is not corrected (M2=M1).

[0130] In step S16, the computer 100 acquires the cumulative number of sheets. The computer 100 causes the second counter 102 to count the cumulative number TM of the printed media 17, and stores the information of the cumulative number TM in the storage unit 107. The computer 100 acquires the information of the cumulative number TM from the count value of the second counter 102 or from the storage unit 107.

[0131] In step S17, the computer 100 corrects the number of times M3 to correspond to the cumulative number of sheets. Specifically, the computer 100 obtains a correction coefficient A corresponding to the cumulative number of sheets TM based on the cumulative number of sheets TM and referring to the third reference data RD3 shown in FIG11. Then, the computer 100 determines the predetermined number of times M3 by multiplying the predetermined number of times M2 by the correction coefficient A. Thus, the predetermined number of times M3 is determined to be the number of times the net is conveyed during cleaning. In the following steps S18 to S26, the computer 100 performs the cleaning operation based on the net conveying number M3.

[0132] In step S18, the computer 100 resets the third counter 103 that counts the number of network transmissions N (N=0).

[0133] In the next step S19, the computer 100 brings the cleaning mechanism 60 into contact with the conveyor belt 27. Specifically, the computer 100 drives the cam motor 69 to rotate the cam member 70 from the first rotational position shown in FIG. 4 to the second rotational position shown in FIG. 5, thereby moving the cleaning mechanism 60 about the rotation axis 61 from the retraction position RP shown in FIG. 2 and 4 to the cleaning position CP shown in FIG. 5. At this cleaning position CP, the wiping part 67 abuts against the conveyor belt 27. At this time, due to the elastic force of the spring 68 that applies force to the cleaning mechanism 60, the wiping part 67 abuts against the surface of the conveyor belt 27 with a predetermined contact pressure. Furthermore, since the wiping part 67 abuts against the portion opposite the receiving part 46 relative to the conveyor belt 27, the decrease in contact pressure caused by the deflection of the conveyor belt 27 is suppressed.

[0134] In step S20, the computer 100 determines whether the number of network transmissions N is less than the predetermined number M3 (N < M3). If N < M3, proceed to step S21; otherwise, if N < M3 (i.e., if N ≥ M3), proceed to step S24.

[0135] In step S21, the computer 100 performs a first cleaning action. That is, the computer 100 performs low-speed cleaning. Specifically, with the wiping unit 67 in contact with the conveyor belt 27, the computer 100 drives the belt motor 97 at a low speed, causing the conveyor belt 27 to rotate at a first speed V1 (see Figure 12). The computer 100 performs one first cleaning action by rotating the conveyor belt 27 by a predetermined amount of rotation. Here, one cleaning action can be based on less than one revolution of the conveyor belt 27, or it can be based on more than one revolution of the conveyor belt 27. In this example, one cleaning action is based on more than one revolution of the conveyor belt 27. The computer 100 may also rotate the conveyor belt 27 multiple times during one cleaning action. The computer 100 performs one low-speed cleaning action by rotating the conveyor belt 27 at a predetermined amount of rotation, for example, within the range of 1 to 5 revolutions.

[0136] In step S22, the computer 100 performs intermittent mesh conveying (intermittent drive). That is, once the first cleaning action of a single unit is completed, the computer 100 causes the drive unit 64 to intermittently drive a predetermined amount. In this example, the predetermined conveying amount during intermittent mesh conveying is the amount of drive that changes the mesh 66 of the wiping unit 67 to a new surface. The predetermined conveying amount is, for example, a predetermined value in the range of 0.5 mm to 5 mm (e.g., 1 mm).

[0137] In step S23, computer 100 increments the network transmission count N (N = N + 1). That is, computer 100 adds "1" to the count value of the third counter 103. Then, computer 100 returns to the processing of step S20.

[0138] Thus, steps S21 to S23 are repeated until the number of times the mesh is conveyed N in step S20 reaches a predetermined number M3 (negative judgment), thereby performing a predetermined number M3 low-speed cleanings, i.e., the first cleaning action. After each cycle, intermittent mesh conveying is performed, during which the conveyor belt 27 continues to rotate at low speed. That is, intermittent mesh conveying is performed while the conveyor belt 27 continues to rotate at low speed without stopping its rotation. Furthermore, the first cleaning action can also be performed only once. Additionally, during intermittent mesh conveying, the rotation of the conveyor belt 27 can be temporarily stopped.

[0139] Furthermore, if the number of conveyor belt cycles reaches a predetermined number M3 in step S20, the computer 100 performs a second cleaning operation in step S24. That is, the computer 100 performs high-speed cleaning. Specifically, with the wiping unit 67 in contact, the computer 100 drives the belt motor 97 at high speed, causing the conveyor belt 27 to rotate at a second speed V2 (see Figure 13). The computer 100 performs one second cleaning operation by rotating the conveyor belt 27 by a predetermined amount of rotation. Here, one second cleaning operation is based on more than one revolution of the conveyor belt 27, but it can also be based on less than one revolution of the conveyor belt 27. The computer 100 rotates the conveyor belt 27 multiple times during one second cleaning operation. The computer 100 performs high-speed cleaning, i.e., the second cleaning operation, while the conveyor belt 27 rotates at a predetermined amount of rotation, for example, within the range of 1 to 5 revolutions. The second cleaning operation is equivalent to fine-tuning cleaning. By performing fine-tuning cleaning at high speed, the cleaning time can be shortened. Furthermore, the predetermined rotation amount of the conveyor belt 27 during high-speed cleaning can be the same as or greater than the predetermined rotation amount of the conveyor belt 27 during low-speed cleaning.

[0140] In step S25, the computer 100 separates the cleaning mechanism 60 from the conveyor belt 27. Specifically, the computer 100 drives the cam motor 69 to rotate the cam member 70 from the second rotational position shown in FIG. 5 to the first rotational position shown in FIG. 4. As a result, by pressing the engaged surface 71 with the engaging surface 70A of the cam member 70, the cleaning mechanism 60 retracts from the cleaning position CP shown in FIG. 5 to the retraction position RP shown in FIG. 4. Through this retraction action, the wiping part 67 separates from the conveyor belt 27.

[0141] In step S26, the computer 100 drives the guide roller 45 and the electrostatic remover brush 55 to come into contact with the conveyor belt 27 by driving the guide motor 98. Thus, when cleaning is complete, the guide roller 45 and the electrostatic remover brush 55 are prepared to come into contact with the conveyor belt 27 in a printable state.

[0142] The control method of the control unit 15 controlling the liquid spraying device 11 through the above-described cleaning control will be described. As described above, the liquid spraying device 11 includes a spraying unit 19, a conveyor belt 27, a net 66, and a drive unit 64. The control method of the liquid spraying device 11 includes a first step of changing the wiping surface 67A of the net 66 that abuts against the conveyor belt 27. The first step is performed a predetermined number of times during the cleaning period of the cleaning conveyor belt 27. Furthermore, in FIG14, the intermittent conveying of the net in step S22 is equivalent to an example of the first step.

[0143] Next, the cleaning operation of the cleaning mechanism 60 on the cleaning conveyor belt 27 will be described. The cleaning operation includes the first cleaning operation shown in FIG12 and the second cleaning operation shown in FIG13. If a predetermined number of times M3 as the number of times the net is conveyed is determined, the cleaning operation is started by controlling the conveyor belt 27 and the cleaning mechanism 60, etc., by the control unit 15.

[0144] First, the low-speed cleaning, or first cleaning action, shown in Figure 12, is performed. First, the guide roller 45 and the electrostatic brush 55 separate from the conveyor belt 27 (upper left view of Figure 12). Next, the wiping section 67 of the cleaning mechanism 60 comes into contact with the conveyor belt 27 (upper right view of Figure 12). Then, in this state, the conveyor belt 27 rotates at low speed, thereby wiping away the ink adhering to the surface of the conveyor belt 27 at low speed by the wiping section 67 (lower right view of Figure 12). For example, after a paper jam, a large amount of ink ejected from the ejector section 19 immediately adheres to the surface of the conveyor belt 27. The ink initially adhering to the surface of the conveyor belt 27 is wiped away at low speed. Therefore, the ink is absorbed by the mesh 66 of the wiping section 67 and wiped away efficiently. That is, the ink is efficiently absorbed by the mesh 66 by wiping away the ink at low speed.

[0145] At the end of each first cleaning action (low-speed cleaning), the mesh 66 is intermittently conveyed with a predetermined amount of material (e.g., 1 mm) (lower left of Figure 12). As a result, the mesh 66 of the wiping section 67 is changed to a new surface.

[0146] Furthermore, when there is a large amount of ink, it may be impossible to completely clean it in a single low-speed cleaning operation. For example, when the printing duty cycle is large, a large amount of ink is ejected from the ejector section 19, resulting in more ink adhering to the surface of the conveyor belt 27 when the first paper jam occurs. In this case, even if the screen 66 of the wiping section 67 is a new surface, it is impossible to completely absorb the ink in a single low-speed cleaning operation. Therefore, the number of low-speed cleaning operations, i.e., the predetermined number of operations, is set to a large value based on the printing duty cycle.

[0147] When the printing duty cycle is large and the amount of ink adhering to the conveyor belt 27 is large, multiple low-speed cleaning actions are performed. One cycle consists of one low-speed cleaning action and one intermittent conveying action at the end of each action (Fig. 12). Then, this cycle is performed a predetermined number of times M3. As a result, even when the amount of ink adhering to the conveyor belt 27 is large, it is possible to transition to the next second cleaning action, which is equivalent to finishing, after the ink has been thoroughly wiped off the surface of the conveyor belt 27.

[0148] Then, the second cleaning action, which is the subsequent finishing cleaning, is performed by high-speed cleaning. This second cleaning action is a finishing cleaning that wipes away the thin layer of ink remaining on the surface of the conveyor belt 27. The second cleaning action is a cleaning that cleanly removes the ink by wiping the surface of the conveyor belt 27, compared to ink absorption. Therefore, in order to increase the area of ​​the conveyor belt 27 surface wiped within a predetermined time, the second cleaning action is performed by high-speed cleaning. Furthermore, because it is high-speed cleaning, compared to a structure that performs the second cleaning action at the same speed as the first cleaning action, it helps to shorten the total time required for cleaning.

[0149] As shown in Figure 13, the second cleaning action involves rotating the conveyor belt 27 at a high speed of V2, thereby cleaning the surface of the conveyor belt 27 at high speed using the wiping unit 67 (upper left view of Figure 13). The second cleaning action is completed in one cycle. Next, by rotating the cleaning mechanism 60 from the cleaning position CP to the retraction position RP, the wiping unit 67 separates from the conveyor belt 27 (upper right view of Figure 13). Afterwards, in preparation for the subsequent printing, the guide roller 45 and the electrostatic brush 55 are positioned in a working position abutting against the conveyor belt 27 (lower right view of Figure 13).

[0150] Furthermore, the cleaning process can be modified based on the ink viscosity. The control unit 15 can predict the ink viscosity based on temperature / humidity information detected by the temperature sensor 94 and humidity sensor 95. The ink viscosity decreases at higher temperatures. Conversely, the ink viscosity decreases at higher humidity levels. In other words, the ink viscosity increases at lower temperatures. And conversely, the ink viscosity increases at lower humidity levels.

[0151] High-viscosity ink is difficult to wipe off. This is because, compared to low-viscosity ink, high-viscosity ink is less easily absorbed by the mesh 66. Low-viscosity ink can be wiped off by being absorbed by the wiping section 67. However, since high-viscosity ink is difficult to absorb by the mesh 66 of the wiping section 67, it needs to be wiped off repeatedly by the wiping section 67. Furthermore, to remove high-viscosity ink, the surface area of ​​the conveyor belt 27 wiped by the wiping section 67 can be increased.

[0152] When the ink has a high viscosity, such as under high temperature and low humidity conditions, the rotational speed of the conveyor belt 27 during each first cleaning action can be increased to increase the surface area wiped by the wiping unit 67 on the conveyor belt 27 compared to the case of low viscosity ink under low temperature and high humidity conditions. In this case, since the absorption performance of the mesh 66 on the ink is not as important as with low viscosity ink, the rotational speed of the conveyor belt 27 can be set to a higher speed compared to the case of low viscosity ink. Therefore, by increasing the surface area (number of times) that the wiping unit 67 wipes the surface of the conveyor belt 27 during the first cleaning action, the wiping performance of high viscosity ink can be improved. In this way, the control unit 15 can also change the cleaning speed of the first cleaning action based on the temperature and humidity information obtained from the temperature sensor 94 and the humidity sensor 95.

[0153] Therefore, the following effects can be obtained according to this embodiment.

[0154] (1) The liquid spraying device 11 includes: a conveyor belt 27 for conveying a medium 17; a spraying section 19 for spraying liquid onto the medium 17 conveyed by the conveyor belt 27; a cleaning mechanism 60 for cleaning the conveyor belt 27; and a control section 15 for controlling the cleaning mechanism 60. The cleaning mechanism 60 includes: a net 66 that abuts against the conveyor belt 27 to wipe the liquid on the conveyor belt 27; and a drive section 64 that changes the wiping surface 67A of the net 66 abutting against the conveyor belt 27. The control section 15 performs a first action of changing the wiping surface 67A of the net 66 abutting against the conveyor belt 27 a predetermined number of times during the cleaning period of cleaning the conveyor belt 27. According to this structure, the first action is performed a predetermined number of times during the cleaning period. That is, the net 66 is driven intermittently. As a result, compared with the prior art structure that always delivers a new net contact surface relative to the belt surface, the life of the net 66 can be extended.

[0155] (2) The control unit 15 acquires information related to the amount of liquid ejected from the ejector 19 toward the medium 17. Based on this information, the control unit 15 determines a predetermined number of times. If the amount of liquid is a first amount, the control unit 15 sets the predetermined number of times to a first number m1. If the amount of liquid is a second amount less than the first amount, the control unit 15 sets the predetermined number of times to a second number m2 less than the first number m1. According to this structure, the number of times the first action is performed is varied depending on the amount of liquid adhering to the conveyor belt 27. For example, when the amount of liquid adhering to the conveyor belt 27 is small, the number of times the first action is reduced. This achieves a cleaning effect and extends the lifespan of the mesh 66.

[0156] (3) The control unit 15 acquires information related to at least one of humidity and temperature within the device body 12. The control unit 15 determines the predetermined number of times based on the information. Since the viscosity of the ink increases under high temperature and low humidity, its wiping ability decreases. According to this structure, the conveyor belt 27 can be properly cleaned by adjusting according to temperature and humidity.

[0157] (4) The control unit 15 acquires information related to the cumulative number of sheets of medium 17 conveyed by the conveyor belt 27. The control unit 15 determines a predetermined number of times based on this information. If the cumulative number of sheets TM of medium 17 is a first number TM1, the control unit 15 sets the predetermined number of times to a first number m1. If the cumulative number of sheets TM of medium 17 is a second number TM2, which is less than the first number TM1, the control unit 15 sets the predetermined number of times to a second number m2, which is less than the first number m1. According to this structure, if the number of sheets of medium 17 increases, the conveyor belt 27 deteriorates. Even in this case, the conveyor belt 27 can be properly cleaned by increasing the predetermined number of times.

[0158] (5) The control unit 15 rotates the conveyor belt 27 at a first speed V1 from the start of cleaning until a predetermined time, and then rotates the conveyor belt 27 at a second speed V2, which is faster than the first speed V1, after the predetermined time. According to this structure, by rotating the conveyor belt 27 at a low speed at the beginning of the cleaning period, the contact time between the conveyor belt 27 and the mesh 66 is increased, thus making it easier for the ink on the conveyor belt 27 to be wiped (absorbed) by the mesh 66. As a result, the predetermined number of cleaning cycles required can be reduced.

[0159] (6) The net 66 is an endless net 66. According to this structure, long lifetime is especially required in the case of an endless net 66, but in this structure, long lifetime is possible.

[0160] (7) The cleaning mechanism 60 includes a wiper 87. The wiper 87 is positioned upstream of the net 66 in the rotational direction BD of the conveyor belt 27 and abuts against the conveyor belt 27 to scrape off the liquid on the conveyor belt 27. With this structure, cleaning can be performed more properly because of the wiper 87.

[0161] (8) The cleaning mechanism 60 is equipped with gears 72 to 75 that transmit power from the drive unit 64. The net 66 is structured such that it receives power from the drive unit 64 via the gears 72 to 75 and is conveyed, thereby changing the wiping surface 67A. The conveying direction WD of the net 66 is consistent with the direction of friction force received from the conveyor belt 27 rotating in the state of contact with the net 66.

[0162] When the direction in which the mesh 66 is conveyed is opposite to the direction of rotation of the conveyor belt 27, a certain amount of drive is required before the conveying action of the mesh 66 begins, until the backlash of the gears 72-75 becomes clogged. Therefore, the conveying amount of the mesh 66 is unstable during intermittent drive. According to this structure, since the backlash is maintained during intermittent drive of the mesh 66, the conveying amount of the mesh 66 is stable. For example, even if the conveying amount of the mesh 66 is assumed to be suppressed to a value close to the minimum required to change to a new wiping surface 67A, the wiping surface 67A of the mesh 66 can be reliably changed to a new surface. Therefore, the mesh 66 of a limited length can be used efficiently in cleaning, thus contributing to the longevity of the cleaning mechanism 60.

[0163] (9) The cleaning mechanism 60 includes a detection unit 83 that detects the rotation amount of the drive unit 64. The detection unit 83 includes: a plurality of detected parts 84B, which are spaced apart in the circumferential direction of a disk 84A that rotates integrally with the rotation axis 76A of the drive unit 64; and a sensor 85 that sequentially detects the plurality of detected parts 84B. In this structure where the mesh 66 is driven intermittently, the conveying amount of the mesh 66, i.e., the rotation amount of the drive unit 64, is small. Therefore, according to the structure of the detection unit, there are cases where it is difficult to detect the rotation amount with the necessary accuracy. In this regard, since the detection unit 83 includes a plurality of detected parts 84B, it is also possible to detect the small rotation amount of the drive unit 64.

[0164] (10) The control method of the liquid spraying device 11, which includes a conveyor belt 27, a spraying section 19, a net 66, and a drive section 64, includes a first step of changing the wiping surface 67A of the net 66 that abuts against the conveyor belt 27. The first step is performed a predetermined number of times during the cleaning period of the conveyor belt 27. According to this method, the lifespan of the net 66 can be extended compared to the prior art structure that constantly feeds a new net contact surface relative to the belt surface.

[0165] Furthermore, the above-described embodiments can also be modified in the manner shown in the following variations. Moreover, examples that appropriately combine the above-described embodiments and the variations shown below can be considered as further variations, as can examples that appropriately combine the variations shown below together.

[0166] In the first cleaning action in step S21, it may also be a low-speed cleaning action (hereinafter referred to as the "first low-speed cleaning action") performed at least once at a lower speed than the predetermined number of times (M3 times). For example, the computer 100 determines whether the number of times the wire feed N is insufficient for the number threshold K. Here, the number threshold K is a threshold for the number of times the first low-speed cleaning action is performed. The number threshold K is a natural number that satisfies 1 ≤ K < M3. If N < K, then in step S21, the first low-speed cleaning action is performed. If N is not < K (i.e., if N ≥ K), then the second low-speed cleaning is performed. Here, the number threshold K can be a fixed value or it can be set according to the amount of ink accidentally sprayed onto the conveyor belt 27 when the first paper jam occurs. For example, the number threshold K can also be determined according to the printing duty cycle value when the first paper jam occurs. The larger the printing duty cycle value, the larger the number threshold K is determined to be. In other words, the number threshold K when the printing duty cycle value is the first printing duty cycle value is set as the first number threshold K1. The threshold K for the second printing duty cycle, which is larger than the first printing duty cycle, is determined to be a value larger than the first printing duty cycle threshold K1. In this modified example, the predetermined time (total execution time) for implementing the first low-speed cleaning action is managed using the threshold K for the number of times the wire conveyor is used. That is, the time obtained by multiplying the execution time of each instance of the first low-speed cleaning action by the threshold K is equivalent to the predetermined time. If the predetermined time has elapsed since the start of cleaning, the process transitions to the second low-speed cleaning action. In this modified example, during the execution of the first cleaning action, the following control is also performed: from the start of cleaning until the predetermined time, the conveyor belt 27 is rotated at a first speed V1, and after the predetermined time, the conveyor belt 27 is rotated at a second speed V2, which is faster than the first speed V1.

[0167] • During cleaning, the control unit 15 intermittently conveys the net 66 while the wiping unit 67 is in the cleaning position CP, which is in contact with the conveyor belt 27. However, this is not a limitation. For example, during cleaning, if a first cleaning action ends, the wiping unit 67 may be switched to a retracted position RP, which is separated from the conveyor belt 27, and the net 66 may be intermittently conveyed while in this retracted position RP. That is, if the first cleaning action ends, the wiping unit 67 may be moved away from the conveyor belt 27, and the net 66 may be intermittently conveyed while in this retracted state. In this case, the following cleaning method may also be performed. The control unit 15 may also include: a separation process, in which the net 66 is switched from the contacting state to the separation state, which is separated from the conveyor belt 27, a predetermined number of times; and a contact process, in which the net 66 is switched from the separation state to the contacting state, a predetermined number of times. Furthermore, the separation process, the first process, and the contact process can be performed sequentially a predetermined number of times during the cleaning period. According to the control method of the liquid spraying device 11, if the net 66 is intermittently driven while it is in contact with the conveyor belt 27, a load may be generated in the drive unit 64. The first action, which changes the wiping surface 67A of the net 66 in contact with the conveyor belt 27, is performed while the net 66 is separated from the conveyor belt 27. Therefore, compared to the case where the first action is performed while the net 66 is in contact with the conveyor belt 27, the influence of the rotational load of the conveyor belt 27 on the conveying action of the net 66 can be suppressed. For example, if the net 66 is less affected by the rotational load of the conveyor belt 27, the accuracy of the conveying amount of the net 66 can be improved.

[0168] • The determination of a predetermined number of times based on information related to the amount of liquid ejected from the ejector 19 toward the medium 17 can also be achieved by multiplying an initial value of a predetermined number of times by a correction coefficient corresponding to the information related to the amount of liquid ejected from the ejector 19 toward the medium 17.

[0169] • The correction based on a predetermined number of times related to at least one of humidity and temperature is not limited to a structure based on second reference data RD2 such as reference table data, but can also be a correction factor corresponding to the predetermined number of times multiplied by at least one of humidity and temperature information.

[0170] • Temperature and humidity related information can be obtained from temperature and humidity sensors inside the main body 12 of the device, or from temperature and humidity sensors outside the device. Here, the temperature and humidity sensor can be composed of a temperature sensor and a humidity sensor, or the temperature sensor and the humidity sensor can be configured into a single sensor unit.

[0171] • In high-temperature and low-humidity conditions, the number of times the mesh 66 is used for wiping can be increased by increasing the rotation speed of the conveyor belt 27 or increasing the number of rotations. That is, in high-temperature and low-humidity conditions, the viscosity of liquids such as ink tends to increase. For example, wiping can remove high-viscosity ink more effectively than absorbing it with the mesh 66. To improve the wiping effect of the mesh 66, the rotation speed of the conveyor belt 27 can be increased or the number of rotations can be increased in high-temperature and low-humidity conditions.

[0172] When the ink viscosity is high, the amount of time the mesh 66 wipes the conveyor belt 27 can be increased by increasing the rotation amount of the conveyor belt 27, rather than increasing the number of times new wiping surfaces 67A of the mesh 66 are exposed. Since highly viscous ink tends to adhere to the conveyor belt 27, it is difficult to remove ink contaminants in a single wipe (e.g., one rotation of the belt). Therefore, the number of times ink contaminants are wiped (e.g., the number of belt rotations) can be increased. The amount of time each wiping surface wipes the conveyor belt 27 can also be increased by increasing the rotation amount of the conveyor belt 27 relative to each wiping surface. On the other hand, when the ink viscosity is high, the number of times new wiping surfaces 67A of the mesh 66 are exposed in a single cleaning cycle can be increased compared to when the viscosity is low.

[0173] • The control unit 15 may acquire information related to at least one of humidity and temperature within the device body 12. Specifically, the control unit 15 is not limited to acquiring information related to both humidity and temperature within the device body 12; it may acquire information related only to humidity or information related only to temperature. It is not limited to humidity and temperature within the device body 12; it may also acquire information related to at least one of humidity and temperature around the outer periphery of the device body 12. If the difference in humidity and temperature between the device body 12 and its outer periphery is within an allowable range, the temperature sensor 94 and humidity sensor 95 may be located either inside or around the outer periphery of the device body 12.

[0174] The correction factor A used in the correction of the predetermined number of times related to the information on the cumulative number of sheets TM is not limited to a straight line graph proportional to the cumulative number of sheets TM shown in Figure 11, but can also be obtained by referring to table data based on stepped or curved graph lines. Alternatively, the correction factor A can be obtained by calculation based on a predetermined formula performed by the calculation unit 108.

[0175] • The number of pre-orders M1 can also be obtained by performing a calculation based on a pre-order formula using the printing duty cycle value. Alternatively, the number of pre-orders M1 can also be obtained by performing a calculation based on pre-order formulas using temperature and humidity values.

[0176] • The net 66 is not limited to being endless. For example, it can be a structure in which one end is wound around the first roller and the other end is wound around the second roller. In this case, it can also be a structure in which the net 66, which is unwound from the first roller, is wound onto the second roller.

[0177] • The control unit 15 can also rotate the conveyor belt 27 at a fixed speed during the cleaning period. Alternatively, the control unit 15 can also increase the speed of the conveyor belt 27 in multiple stages or proportionally to time during the cleaning period.

[0178] Patent Document 1 suffers from waste because a fixed amount of screen 66 is used for cleaning regardless of the printing duty cycle. On the other hand, in this embodiment, waste of screen 66 is suppressed because the amount by which the wiping surface 67A of the screen 66 is changed (the number of screen feeds) is varied according to the printing duty cycle. For example, if the screen 66 is fed at a fixed feed rate regardless of the printing duty cycle, even at higher printing duty cycles when more ink needs to be wiped away, a larger screen feed rate needs to be set based on the case of more ink to ensure the necessary cleaning quality. In this case, the screen becomes wasteful when less ink is wiped away at lower printing duty cycles.

[0179] • The cleaning unit 60 may also be a structure without the wiper 87.

[0180] • The detection unit 83 can also be a rotary encoder. That is, the rotation of the rotary shaft 76A can also be detected by a rotary encoder.

[0181] • The conveyor belt 27 can also be rotated multiple times relative to a wiping surface 67A. In this case, compared with the prior art, it is possible to extend the life of the mesh 66, and thus extend the life of the cleaning mechanism 60.

[0182] • Medium 17 is not limited to paper, etc., but can also be cloth, non-woven fabric, paperboard, synthetic resin film, laminated medium, etc.

[0183] • The liquid ejection device 11 is not limited to an inkjet printing device (printer) for printing on paper, but can also be a dyeing device. The conveyor belt may also have an adhesive layer on its surface.

[0184] The following describes the technical ideas and effects learned from the above-described embodiments and their variations.

[0185] (A) A liquid spraying device includes: a conveyor belt for conveying a medium; a spraying unit for spraying liquid onto the medium conveyed by the conveyor belt; a cleaning mechanism for cleaning the conveyor belt; and a control unit for controlling the cleaning mechanism, the cleaning mechanism including: a net that abuts against the conveyor belt and wipes the liquid on the conveyor belt; and a drive unit for changing the wiping surface of the net that abuts against the conveyor belt, the control unit performing a first action of changing the wiping surface of the net that abuts against the conveyor belt a predetermined number of times during the cleaning period of cleaning the conveyor belt.

[0186] According to this structure, the first action is performed a predetermined number of times during the cleaning period. That is, the mesh is driven intermittently. As a result, the lifespan of the mesh can be extended compared to the prior art structure that constantly feeds a new mesh contact surface relative to the belt surface.

[0187] (B) In the liquid ejection device described in (A) above, the control unit may acquire information related to the amount of liquid ejected from the ejection unit toward the medium, and determine the predetermined number of times based on the information. If the amount of liquid is a first amount, the predetermined number of times is set as the first number; if the amount of liquid is a second amount less than the first amount, the predetermined number of times is set as the second number less than the first number.

[0188] According to this structure, the number of times the first action is performed is varied depending on the amount of liquid adhering to the conveyor belt 27. For example, when the amount of liquid adhering to the conveyor belt is small, the number of times the first action is reduced. This allows for achieving a cleaning effect and extending the lifespan of the mesh 66.

[0189] (C) In the liquid ejection device described in (A) or (B) above, the control unit may acquire information related to at least one of humidity and temperature within the device body, and determine the predetermined number of times based on the information.

[0190] Because the viscosity of the ink increases under high temperature and low humidity, its erasability decreases. Based on this structure, the tape can be properly cleaned by adjusting for changes in temperature and humidity.

[0191] (D) In ​​any of the liquid ejection devices described in (A) to (C) above, the control unit may acquire information related to the cumulative number of sheets of medium conveyed by the conveyor belt and determine the predetermined number of times based on the information. If the cumulative number of sheets is a first number, the predetermined number of times is set as the first number. If the cumulative number of sheets of medium is a second number less than the first number, the predetermined number of times is set as the second number less than the first number.

[0192] According to this structure, if the number of media sheets increases, the conveyor belt deteriorates. Even in this case, the mesh can be properly cleaned by increasing the predetermined number of cleaning cycles.

[0193] (E) In any of the liquid ejection devices described in (A) to (D) above, the control unit may rotate the conveyor belt at a first speed from the start of cleaning until a predetermined time, and after the predetermined time, rotate the conveyor belt at a second speed faster than the first speed.

[0194] According to this structure, by rotating the conveyor belt at a low speed at the beginning of the cleaning process, the contact time between the conveyor belt and the mesh is increased, thus making it easier for the ink on the conveyor belt to be wiped (absorbed) by the mesh. As a result, the predetermined number of cleaning cycles can be reduced.

[0195] (F) In any of the liquid ejection devices described in (A) to (E) above, the net may also be an endless net.

[0196] According to this structure, long lifespan is particularly required in the case of endless meshes, but with this structure, long lifespan is achievable.

[0197] (G) In any of the liquid spraying devices described in (A) to (F) above, the cleaning mechanism may also include a wiper, which is positioned upstream of the net in the rotational direction of the conveyor belt and abuts against the conveyor belt to scrape off the liquid on the conveyor belt.

[0198] Because of this structure, which also includes a wiper, cleaning can be performed more properly.

[0199] (H) In any of the liquid spraying devices described in (A) to (G) above, the cleaning mechanism may include a gear that transmits power from the drive unit, and the net is configured to receive power from the drive unit via the gear and be conveyed, thereby changing the wiping surface. The direction in which the net is conveyed is consistent with the direction in which the net receives frictional force from the conveyor belt rotating in the state of contact with the net.

[0200] When the direction in which the net is conveyed is opposite to the direction of rotation of the conveyor belt, a driving amount is required until the gear backlash becomes clogged before the net conveying operation begins. Therefore, the net conveying amount is unstable during intermittent driving. According to this structure, since the gear backlash is maintained during intermittent driving of the net, the net conveying amount is stable.

[0201] (I) In any one of (A) to (H) above, the liquid spraying device may also include a cleaning mechanism that includes a detection unit for detecting the amount of rotation of the drive unit. The detection unit includes: a plurality of detected parts that are spaced apart in the circumferential direction of a disk that rotates integrally with the rotation axis of the drive unit; and a sensor that sequentially detects the plurality of detected parts.

[0202] According to this structure, in the case of an intermittently driven mesh, the amount of mesh transported, i.e., the rotation amount of the drive unit, is small. Therefore, according to the structure of the detection unit, it is difficult to detect the rotation amount with the necessary accuracy. According to this structure, since the detection unit has multiple detected parts, it is also possible to detect the small rotation amount of the drive unit.

[0203] (J) A control method for a liquid spraying device, the liquid spraying device comprising: a conveyor belt for conveying a medium; a spraying part for spraying liquid onto the medium conveyed by the conveyor belt; a net for abutting the conveyor belt and wiping the liquid on the conveyor belt; and a drive unit for changing the wiping surface of the net abutting the conveyor belt, wherein the control method for the liquid spraying device includes a first step of changing the wiping surface of the net abutting the conveyor belt, and the first step is performed a predetermined number of times during a cleaning period of cleaning the conveyor belt.

[0204] According to this method, the lifespan of the mesh can be extended compared to the existing structure that always feeds new mesh contact surfaces relative to the belt surface.

Claims

1. A liquid ejection device, characterized in that, The device comprises: a conveyor belt for conveying a medium; a spraying unit for spraying liquid onto the medium conveyed by the conveyor belt; a cleaning mechanism for cleaning the conveyor belt; and a control unit for controlling the cleaning mechanism. The cleaning mechanism comprises: a net that abuts against the conveyor belt and wipes the liquid on the conveyor belt; and a drive unit that changes the wiping surface of the net abutting against the conveyor belt. The control unit performs a predetermined number of cleaning actions and a first action during the cleaning of the conveyor belt. The cleaning action rotates the conveyor belt while the net is abutting against the conveyor belt. The first action changes the wiping surface of the net abutting against the conveyor belt. The control unit acquires information related to the amount of liquid sprayed from the spraying unit toward the medium. Based on the information, the control unit determines the predetermined number of times. If the amount of liquid is a first amount, the predetermined number of times is set as a first number. If the amount of liquid is a second amount less than the first amount, the predetermined number of times is set as a second number less than the first number.

2. The liquid ejection device according to claim 1, characterized in that, The control unit acquires information related to at least one of humidity and temperature within the device body, and determines the predetermined number of times based on the information.

3. The liquid ejection device according to claim 1, characterized in that, The control unit acquires information related to the cumulative number of sheets of medium conveyed by the conveyor belt, and determines the predetermined number of times based on the information. If the cumulative number of sheets of medium is a first number, the predetermined number of times is set as the first number. If the cumulative number of sheets of medium is a second number less than the first number, the predetermined number of times is set as the second number less than the first number.

4. The liquid ejection device according to claim 1, characterized in that, The control unit rotates the conveyor belt at a first speed from the start of cleaning until a predetermined time, and then rotates the conveyor belt at a second speed faster than the first speed after the predetermined time.

5. The liquid ejection device according to claim 1, characterized in that, The network is an endless network.

6. The liquid ejection device according to claim 1, characterized in that, The cleaning mechanism includes a wiper positioned upstream of the net in the rotational direction of the conveyor belt and abutting against the conveyor belt to scrape off the liquid on the conveyor belt.

7. The liquid ejection device according to claim 1, characterized in that, The cleaning mechanism includes a gear that transmits power from the drive unit. The net is configured to receive power from the drive unit via the gear and be conveyed, thereby changing the wiping surface. The direction in which the net is conveyed is consistent with the direction in which the net receives frictional force from the conveyor belt rotating in the state of contact with the net.

8. The liquid ejection device according to claim 1, characterized in that, The cleaning mechanism includes a detection unit that detects the rotation amount of the drive unit. The detection unit includes: a plurality of detected parts, which are spaced apart in the circumferential direction of a disk that rotates integrally with the rotation axis of the drive unit; and a sensor that sequentially detects the plurality of detected parts.

9. A control method for a liquid ejection device, characterized in that, The liquid ejection device includes: a conveyor belt for conveying a medium; an ejection section for ejecting liquid onto the medium conveyed by the conveyor belt; a net that abuts against the conveyor belt and wipes the liquid on the conveyor belt; and a drive unit for changing the wiping surface of the net that abuts against the conveyor belt. The control method includes: a cleaning step in which the conveyor belt is rotated while the net is abutting against the conveyor belt; and a first step in which the wiping surface of the net that abuts against the conveyor belt is changed. During the cleaning period of cleaning the conveyor belt, the cleaning step and the first step are performed a predetermined number of times. Information related to the amount of liquid ejected from the ejection section toward the medium is obtained. Based on the information, the predetermined number of times is determined. If the amount of liquid is a first amount, the predetermined number of times is set as a first number. If the amount of liquid is a second amount less than the first amount, the predetermined number of times is set as a second number less than the first number.

Images