Printing device and wiping member cleaning method

Abstract

To remove ink from a wiping member that wipes an ink discharge face of a discharge head, the discharge head discharging ink from a nozzle disposed on the ink discharge face.SOLUTION: Foamy cleaning liquid Lb (first cleaning liquid) is supplied to a wiper 54 (wiping member), so that the foamy cleaning liquid Lb can remove ink from the wiper 54. Furthermore, the wiper 54 contains bubbles, so that it can remove the ink with strong cleaning power, and also can reduce the amount of the foamy cleaning liquid Lb required for ink removal.SELECTED DRAWING: Figure 5

Description

[Technical field]

[0001] The present invention relates to a technique for cleaning a wiping member that wipes the ink ejection surface of an ejection head that ejects ink from nozzles provided on the ink ejection surface. [Background technology]

[0002] In a discharge head that discharges ink from nozzles, it is necessary to remove ink adhering to the discharge head. Therefore, the technology described in Patent Document 1 removes ink by supplying a cleaning liquid to the discharge head. In addition, the technology described in Patent Document 2 removes ink by supplying a cleaning liquid to the discharge head and then wiping the discharge head with a wiping member. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 11-198396 [Patent Document 2] JP 2016-155252 A Summary of the Invention [Problem to be solved by the invention]

[0004] For example, according to the technology of Patent Document 2, while the ink adhering to the ejection head can be removed by a wiping member, the ink removed from the ejection head adheres to the wiping member. If the ink remains adhering to the wiping member when the ink is next removed from the ejection head, wiping the ejection head with the wiping member may contaminate the ejection head. Therefore, in order to reliably remove the ink from the ejection head, it is necessary to remove the ink adhering to the wiping member.

[0005] The present invention has been made in consideration of the above problems, and has an object to make it possible to remove ink from a wiping member that wipes the ink ejection surface of an ejection head that ejects ink from nozzles provided on the ink ejection surface. [Means for solving the problem]

[0006] The printing device of the present invention includes an ejection head that ejects ink from nozzles provided on the ink ejection surface, a wiping member that wipes off ink adhering to the ink ejection surface, a drive unit that performs wiping by moving the wiping member in contact with the ink ejection surface relative to the ejection head, and a cleaning liquid supply unit that supplies a first cleaning liquid containing air bubbles to the wiping member.

[0007] The wiping member cleaning method according to the present invention includes a step of performing wiping by bringing the wiping member into contact with an ejection head that ejects ink from nozzles provided on an ink ejection surface while moving the wiping member relative to the ejection head, and a step of supplying a first cleaning liquid containing air bubbles to the wiping member.

[0008] In the present invention (printing device and wiping member cleaning method) configured as described above, the first cleaning liquid is supplied to the wiping member, so that the ink can be removed from the wiping member by the first cleaning liquid. Moreover, since the first cleaning liquid contains air bubbles, it can remove the ink with a strong cleaning power, and the amount of the first cleaning liquid required to remove the ink can also be reduced.

[0009] The printing device may be configured such that the cleaning liquid supply unit selectively supplies either the first cleaning liquid or a second cleaning liquid different from the first cleaning liquid to the wiping member. In this configuration, various processes other than removing ink with the first cleaning liquid can be performed on the wiping member.

[0010] Also, various specific compositions of the second cleaning liquid are considered. For example, a second cleaning liquid that does not contain air bubbles may be supplied to the wiping member. Such a second cleaning liquid can be used, for example, to wash away the first cleaning liquid from the wiping member. That is, since the first cleaning liquid contains air bubbles, it does not flow immediately after being supplied to the wiping member and remains on the wiping member. Therefore, the first cleaning liquid can be washed away with the second cleaning liquid that does not contain air bubbles to clean the wiping member.

[0011] The printing device may be configured such that the cleaning liquid supply unit has an original liquid supply unit that supplies cleaning liquid that does not contain bubbles and a gas supply unit that supplies gas, and supplies a first cleaning liquid generated by mixing the cleaning liquid supplied from the original liquid supply unit with the gas supplied from the gas supply unit to the wiping member, and supplies the cleaning liquid supplied from the original liquid supply unit as the second cleaning liquid to the wiping member while the supply of gas from the gas supply unit is stopped. With this configuration, the first cleaning liquid and the second cleaning liquid can be easily used depending on whether or not gas is mixed with the cleaning liquid (original liquid).

[0012] Alternatively, the second cleaning liquid containing air bubbles may be supplied to the wiping member. In this case, by making the state of the air bubbles contained in the first cleaning liquid different from the state of the air bubbles contained in the second cleaning liquid, various treatments can be performed on the wiping member.

[0013] Specifically, the size of the bubbles contained in the second cleaning liquid may be larger than the size of the bubbles contained in the first cleaning liquid. Such coarse bubbles in the second cleaning liquid tend to disappear quickly compared to the fine bubbles in the first cleaning liquid. Therefore, for example, the second cleaning liquid can be used to wash away the first cleaning liquid from the wiping member. That is, since the bubbles contained in the first cleaning liquid are fine, the first cleaning liquid does not flow immediately after being supplied to the wiping member, but remains on the wiping member. In contrast, since the bubbles contained in the second cleaning liquid are coarse, the second cleaning liquid flows quickly after being supplied to the wiping member. Therefore, the first cleaning liquid can be washed away with the second cleaning liquid to clean the wiping member.

[0014] The printing device may be configured such that the cleaning liquid supply unit has an original liquid supply unit that supplies cleaning liquid that does not contain bubbles and a gas supply unit that supplies gas, and the speed at which the cleaning liquid supplied from the original liquid supply unit is mixed with the gas supplied from the gas supply unit is changed to selectively generate a first cleaning liquid and a second cleaning liquid with different bubble states and supply them to the wiping member. In this configuration, the first cleaning liquid and the second cleaning liquid can be easily used separately by changing the speed at which the gas is mixed with the cleaning liquid (original liquid).

[0015] The printing device may be configured so that after the drive unit performs wiping, the cleaning liquid supply unit supplies a first cleaning liquid to the wiping member, and before the drive unit starts wiping, the cleaning liquid supply unit supplies a second cleaning liquid to the wiping member, thereby removing the first cleaning liquid adhering to the wiping member from the wiping member. In this configuration, ink that has adhered to the wiping member by performing wiping can be removed from the wiping member by the first cleaning liquid. Also, before wiping starts, the first cleaning liquid remaining on the wiping member can be washed away by the second cleaning liquid, and wiping can be performed by a clean wiping member.

[0016] The printing device may be configured so that, while the first cleaning liquid is supplied from the cleaning liquid supply unit to the wiping member, the speed at which the drive unit moves the wiping member relative to the cleaning liquid supply unit is changed to change the thickness of the first cleaning liquid adhering to the wiping member. With this configuration, an appropriate thickness of the first cleaning liquid can be applied to the wiping member to remove ink from the wiping member. Effect of the Invention

[0017] As described above, according to the present invention, it is possible to remove ink from a wiping member that wipes the ink ejection surface of a ejection head that ejects ink from nozzles provided on the ink ejection surface. [Brief description of the drawings]

[0018] [Figure 1] FIG. 1 is a front view showing an example of a printing apparatus according to an embodiment of the present invention. [Diagram 2] FIG. 2 is a block diagram showing an electrical configuration of the printing apparatus shown in FIG. [Diagram 3] FIG. 2 is a bottom view illustrating a schematic configuration of the head unit. [Figure 4] FIG. 2 is a perspective view illustrating a configuration of a maintenance unit. [Diagram 5] FIG. 2 is a diagram illustrating a configuration of a first example of a cleaning liquid supply unit. [Figure 6] 6 is a diagram showing, in table form, the operation of the cleaning liquid supply unit in FIG. 5; [Figure 7A] FIG. 2 is a diagram showing a first example of a specific configuration of a concentrate discharge unit; [Figure 7B] FIG. 13 is a diagram showing a second example of a specific configuration of the concentrate discharge portion. [Figure 8A] FIG. 4 is a diagram showing a first example of a specific configuration of an air discharge portion. [Figure 8B] FIG. 11 is a diagram showing a second example of a specific configuration of the air discharge portion. [Figure 9] 6 is a flowchart showing an example of maintenance performed on the ejection head. [Figure 10] 10 is a diagram showing a schematic diagram of a first example of the operation executed according to the flowchart of FIG. 9; [Figure 11] 10 is a diagram illustrating a second example of the operation executed according to the flowchart of FIG. 9. [Figure 12] FIG. 11 is a diagram illustrating a configuration of a second example of a cleaning liquid supply unit. [Figure 13] FIG. 13 is a diagram illustrating a configuration of a third example of a cleaning liquid supply unit. [Figure 14] 6 is a diagram showing, in table form, the operation of discharging two types of foamy cleaning liquid by the cleaning liquid supply unit in FIG. 5; [Figure 15A] 5 is a schematic diagram of the wiper 54 and the wiper lifting mechanism 55 as viewed from the Y direction. [Figure 15B] 5 is a schematic diagram of the wiper 54 and the wiper lifting mechanism 55 as viewed from the Y direction. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0019] FIG. 1 is a front view showing a schematic diagram of an example of a printing device according to the present invention, and FIG. 2 is a block diagram showing an electrical configuration of the printing device of FIG. 1. In FIG. 1 and the following figures, the horizontal X direction, the horizontal Y direction perpendicular to the X direction, and the vertical Z direction are appropriately shown. The printing device 1 prints an image on the web W by ejecting ink onto the web W by an inkjet method while transporting a long strip-shaped web W in a roll-to-roll manner. The material of the web W is paper or film, and the web W is flexible. The printing device 1 includes a control unit 10 that controls the entire device, and the control required for printing and maintenance is executed by the control unit 10.

[0020] The control unit 10 is a computer having a calculation unit 11, a storage unit 12, and a communication unit 13. The calculation unit 11 is configured with a processor such as a CPU (Central Processing Unit) and executes calculations necessary for printing and maintenance. The storage unit 12 is a storage device such as an HDD (Hard Disk Drive) and an SSD (Solid State Drive) and stores data necessary for printing and maintenance. The communication unit 13 executes communication with an external device such as an external computer.

[0021] Furthermore, the printing device 1 includes a display 14 configured, for example, by a liquid crystal monitor, and the control unit 10 notifies the worker of information by displaying the information on the display 14. The display 14 is configured as a touch panel and has a function of accepting input operations by the worker. Information input to the display 14 by the worker is transmitted to the control unit 10 and used for control by the control unit 10. The input function may be configured by input devices such as a keyboard and a mouse provided separately from the display 14.

[0022] The printing device 1 includes a transport section 2 that transports the web W. The transport section 2 includes a feed roller 21 and a take-up roller 22, and transports the web W in a roll-to-roll manner by winding the web W fed by the feed roller 21 with the take-up roller 22. The transport section 2 includes a take-up section 23 that takes in the web W fed from the feed roller 21, between the feed roller 21 and the take-up roller 22. The take-up section 23 includes two drive rollers 231, two nip rollers 232, and an edge position adjustment section 234 provided between the two drive rollers 231. Each drive roller 231 rotates by the driving force of a motor while winding the web W around it, thereby driving the web W. The two nip rollers 232 are provided corresponding to the two drive rollers 231, respectively, and each nip roller 232 sandwiches the web W between the corresponding drive roller 231. The edge position adjustment unit 234 adjusts the position of the edge of the web W in the X direction, which is the width direction of the web W.

[0023] The transport section 2 also has a plurality of support rollers 24 that support the web W between the take-in section 23 and the winding roller 22. These support rollers 24 transport the web W in the Y direction while supporting the web W, onto which ink is ejected by an inkjet system, from below. In particular, the support rollers 24 are arranged at an incline so that the support rollers 24 on the downstream side in the transport direction (Y direction) of the web W are positioned higher. Therefore, the web W transported by these support rollers 24 is transported at an incline so as to rise toward the Y direction.

[0024] Furthermore, the conveying section 2 has a plurality of support rollers 25 that support the web W between the support roller 24 and the winding roller 22, and a drying section 26 that is disposed between the support rollers 25 and the winding roller 22. The drying section 26 has a heat drum 261 and a support roller 262 that supports the web W moving from the heat drum 261 to the winding roller 22. The heat drum 261 is rotated in response to the conveyance of the web W, and dries the web W by heating the web W with a built-in heater. The conveying section 2 also has a plurality of support rollers 27 that support the web W moving from the drying section 26 to the winding roller 22. The conveying section 2 also has a drive roller 281 and a nip roller 282 that are disposed between the support roller 27 and the winding roller 22. The drive roller 281 drives the web W by rotating by the driving force of a motor while winding the web W around it. The nip roller 282 sandwiches the web W between the drive roller 281 and the nip roller 282.

[0025] The printing device 1 has a plurality of (six) head units 3 (FIG. 3) facing from above the web W supported by a plurality of support rollers 24. FIG. 3 is a bottom view showing a schematic configuration of the head unit. The head unit 3 has a plurality of (five) ejection heads 31. The ejection heads 31 are arranged in two rows in a staggered pattern in the X direction. In other words, a head row C31 consisting of three ejection heads 31 arranged parallel to the X direction and a head row C31 consisting of two ejection heads 31 arranged parallel to the X direction are provided in the Y direction. The bottom surface of each ejection head 31 is a nozzle-facing plane 310 facing the web W, and a plurality of nozzles 311 are opened in the nozzle-facing plane 310. The plurality of nozzles 311 are arranged in a staggered pattern in the X direction facing the web W from above, and each nozzle 311 ejects ink to the web W by an inkjet method. This head unit 3 has a head holding member 32 that holds each ejection head 31. The head holding member 32 has a plurality of head insertion holes 321 provided corresponding to the plurality of ejection heads 31, and the plurality of ejection heads 31 are fixed to the head holding member 32 in a state where they are inserted into the corresponding head insertion holes 321. Such a head holding member 32 can be made of a non-elastic material such as metal or resin.

[0026] 1, the posture of each of the multiple head units 3 is set according to the inclination of the web W supported by the multiple support rollers 24. In other words, the multiple head units 3 are arranged such that the more upstream the head unit 3 is in the transport direction of the web W, the greater the inclination with respect to the Z direction. However, the most downstream head unit 3 in the transport direction (Y direction) of the web W is arranged horizontally and is not inclined with respect to the Z direction, and the head units 3 other than the most downstream head unit 3 are inclined so as to become higher toward the transport direction of the web W. The inclination of the head unit 3 can be evaluated by the angle that the nozzle-facing plane 310 of the ejection head 31 in which the nozzles 311 are formed makes with respect to the Z direction.

[0027] Each of the multiple head units 3 ejects ink of a different color, including yellow, magenta, cyan, and black, from the nozzles 311 in response to a command from the control unit 10. This makes it possible to print a color image on the web W. However, the number of head units 3 and the colors of the ink are not limited to this example.

[0028] The printing device 1 also includes a plurality of lifting and lowering drive units 4 provided corresponding to the plurality of head units 3, respectively. Each lifting and lowering drive unit 4 can raise and lower the corresponding head unit 3 in response to a command from the control unit 10, thereby positioning the head unit 3 at one of a plurality of positions having different heights. In FIG. 1, each head unit 3 is positioned at a printing height h0 that is closest to the web W. Such lifting and lowering drive unit 4 can be realized by a well-known specific configuration, and can be configured to raise and lower the head unit 3 by, for example, driving a ball screw or an eccentric cam with a motor.

[0029] Furthermore, the printing device 1 includes a maintenance unit 5 (FIG. 4) that performs maintenance on the head unit 3, and a horizontal drive unit 61 that drives the maintenance unit 5 in the horizontal direction (X direction). The maintenance unit 5 and the horizontal drive unit 61 are provided for each of the multiple head units 3. The maintenance unit 5 is moved in the X direction, which is the cleaning direction, by the horizontal drive unit 61, to perform wiping, which will be described later, on the head unit 3. The horizontal drive unit 61 can be configured, for example, by a rail that supports the maintenance unit 5 and extends in the X direction, and a linear motor that drives the maintenance unit 5 in the X direction. Also, instead of the linear motor, a mechanism that uses a motor to rotate a pulley around which a belt attached to the maintenance unit 5 is wound, or a ball screw that linearly moves the maintenance unit 5 may be used. Next, details of the maintenance unit 5 will be described.

[0030] FIG. 4 is a perspective view showing a schematic configuration of the maintenance unit. As described above, a maintenance unit 5 is provided for each of the multiple head units 3, and each maintenance unit 5 faces the corresponding head unit 3 from below. In this case, the maintenance unit 5 is also disposed at an inclination according to the inclination of the head unit 3. However, since the inclination of the maintenance unit 5 is slight, the inclination of the maintenance unit 5 is not reflected in FIG. 4 and the following figures. In addition, since the multiple maintenance units 5 provided corresponding to the multiple head units 3 have a common configuration, the following description will focus on one maintenance unit 5.

[0031] The maintenance unit 5 has a base member 51 having a rectangular parallelepiped shape elongated in the X direction, and a horizontal drive unit 61 (FIG. 2) drives the base member 51 in the X direction while supporting it. The base member 51 is provided with a cap insertion hole 511 that has a rectangular parallelepiped shape elongated in the X direction and opens upward. The maintenance unit 5 has a plurality of cap insertion holes 511 corresponding to the plurality of ejection heads 31 of the opposing head unit 3. In this way, the plurality of cap insertion holes 511 are arranged in a staggered two rows in the X direction.

[0032] Further, the maintenance unit 5 has caps 52 fitted into each of the multiple cap insertion holes 511. In this way, the maintenance unit 5 has multiple caps 52 corresponding to the multiple ejection heads 31 of the opposing head unit 3, and each cap 52 faces the corresponding ejection head 31 from below and receives ink dropping from the ejection head 31. The multiple caps 52 are arranged in two rows in a staggered manner in the X direction, in other words, a cap column C52 consisting of three caps 52 arranged parallel to the X direction and a cap column C52 consisting of two caps 52 arranged parallel to the X direction are provided in the Y direction.

[0033] The maintenance unit 5 has a seal member 53 arranged on the upper surface of the base member 51. The seal member 53 is a frame having a rectangular shape in a plan view from the Z direction, and is provided for each of the multiple caps 52. This seal member 53 protrudes a predetermined height from the upper surface of the base member 51 and surrounds the corresponding cap 52 from the outside in a plan view. This seal member 53 is made of an elastic member such as rubber or silicone, and elastically deforms in response to an external force. A similar seal member may be arranged along the flat edge portion of the base member 51.

[0034] The maintenance unit 5 also has a wiper 54 made of an elastic member that is elastically deformable, such as rubber or silicon. The wiper 54 is a blade having a flat plate shape extending parallel to the Y direction, and stands upright from the upper surface of the base member 51. The wiper 54 is provided corresponding to each of the multiple (two) cap rows C52, and each wiper 54 is disposed on the upstream side of the corresponding cap row C52 in the X direction (cleaning direction). In this way, multiple (two) wipers 54 are arranged in the Y direction at the upstream end of the base member 51 in the X direction. Each wiper 54 scrapes off ink from the nozzle-facing plane 310 of the ejection head 31, as described below.

[0035] Furthermore, the maintenance unit 5 has a tank mounting portion 512 provided for each of the wipers 54. The tank mounting portion 512 is a hole that opens upward and is formed in the base member 51, and is located below the corresponding wiper 54, and a waste liquid container 513 is inserted into each tank mounting portion 512. In this way, the waste liquid container 513 is provided below each of the wipers 54. Each waste liquid container 513 is a box-shaped tank that opens upward and faces the corresponding wiper 54 from below. The waste liquid container 513 stores ink that has been scraped off by the wiper 54 and dropped from the wiper 54. The waste liquid container 513 does not need to be a box, and may be a pan that receives ink.

[0036] The printing device 1 also includes a cleaning liquid supply unit 8 that supplies liquid for cleaning the wiper 54. In particular, the cleaning liquid supply unit 8 has a mechanism for selectively supplying one of two types of liquid to the wiper 54. Next, the configuration and operation of the cleaning liquid supply unit 8 will be described.

[0037] Fig. 5 is a diagram showing a schematic configuration of a first example of the cleaning liquid supply unit, and Fig. 6 is a diagram showing in table form the operation of the cleaning liquid supply unit of Fig. 5. This cleaning liquid supply unit 8 has an undiluted liquid discharge unit 81 that discharges cleaning liquid Lo (undiluted liquid), an air discharge unit 82 that discharges air A, a pipe 841 that guides the cleaning liquid Lo discharged from the undiluted liquid discharge unit 81 to a mixing region 83, a pipe 842 that guides the air A discharged from the air discharge unit 82 to the mixing region 83, and a cleaning liquid nozzle 85 that communicates with the mixing region 83. The cleaning liquid nozzle 85 has an opening 851 that opens downward, and discharges liquid from the opening 851. In addition, the cleaning liquid Lo discharged from the air discharge unit is, for example, a liquid containing a surfactant and does not contain air bubbles.

[0038] As shown in the "bubble mode" of FIG. 6, when the raw liquid discharger 81 discharges the cleaning liquid Lo while the air discharger 82 discharges air, the cleaning liquid Lo discharged from the raw liquid discharger 81 and the air discharged from the air discharger 82 are mixed in the mixing region 83. As a result, the foamed air A is mixed with the cleaning liquid Lo, and a foamed cleaning liquid Lb (= cleaning liquid Lo + air A) containing air bubbles is generated. Then, this foamed cleaning liquid Lb is discharged from the opening 851 of the cleaning liquid nozzle 85. Also, as shown in the "rinse mode" of FIG. 6, when the raw liquid discharger 81 discharges the cleaning liquid Lo with the air discharger 82 stopping air discharge, the cleaning liquid Lo discharged from the raw liquid discharger 81 flows into the cleaning liquid nozzle 85 via the mixing region 83 and is discharged from the cleaning liquid nozzle 85. In other words, the cleaning liquid supply unit 8 discharges foamed cleaning liquid Lb containing air bubbles from the cleaning liquid nozzle 85 by executing the bubble mode, and discharges cleaning liquid Lo not containing air bubbles from the cleaning liquid nozzle 85 by executing the rinse mode.

[0039] Various specific configurations of the above-mentioned stock solution discharge unit 81 are assumed. Here, two representative examples (FIGS. 7A and 7B) will be described. FIG. 7A is a diagram showing a first example of a specific configuration of the stock solution discharge unit. The stock solution discharge unit 81 in FIG. 7A has a syringe 811, an actuator 812a that drives the syringe 811, and a cleaning solution tank 813 that stores a cleaning solution Lo. The syringe 811 has a barrel 811b and a plunger 811p fitted in the barrel 811b, and the plunger 811p moves relative to the syringe 811 when the actuator 812a drives the plunger 811p. Note that the driving means for driving the plunger 811p is not limited to the actuator 812a, and may be, for example, a motor. The barrel 811b and the cleaning solution tank 813 are connected by a pipe 814, and a check valve 815 is attached to the pipe 814. The check valve 815 permits the cleaning solution Lo to flow from the cleaning solution tank 813 to the barrel 811b, but prohibits the cleaning solution Lo from flowing from the barrel 811b to the cleaning solution tank 813. In addition, the barrel 811b is connected to a discharge port 816 of the raw solution discharge part 81 by a pipe 817, and a check valve 818 is attached to the pipe 817. The check valve 818 permits the cleaning solution Lo to flow from the barrel 811b to the discharge port 816, but prohibits the cleaning solution Lo from flowing from the discharge port 816 to the barrel 811b.

[0040] In the concentrate discharge unit 81, when the actuator 812a moves the plunger 811p in a direction to pull the plunger 811p out of the barrel 811b (to the left in FIG. 7A), the cleaning liquid Lo flowing out from the cleaning liquid tank 813 is filled into the barrel 811b. When the actuator 812a moves the plunger 811p in a direction to push the plunger 811p into the barrel 811b (to the right in FIG. 7A), the cleaning liquid Lo flowing out from the barrel 811b is discharged from the discharge port 816 into the mixing region 83. This operation of the actuator 812a is controlled by the control unit 10.

[0041] Fig. 7B is a diagram showing a second example of a specific configuration of the stock solution discharge unit. The stock solution discharge unit 81 in Fig. 7A has a cleaning solution tank 813 that stores the cleaning solution Lo, a pipe 819 that connects the outlet 816 of the stock solution discharge unit 81, and a liquid delivery pump 812p attached to the pipe 819. A gear pump, a diaphragm pump, or the like can be used as the liquid delivery pump 812p. The cleaning solution Lo delivered from the cleaning solution tank 813 to the outlet 816 by the liquid delivery pump 812p is delivered from the outlet 816 to the mixing region 83. This operation of the liquid delivery pump 812p is controlled by the control unit 10.

[0042] Various specific configurations of the air discharge part as described above are assumed. Here, two representative examples (FIGS. 8A and 8B) will be described. FIG. 8A is a diagram showing a schematic diagram of a first example of a specific configuration of the air discharge part. This air discharge part 82 includes an inlet 821 that takes in air A, an outlet 822 that discharges air A, a pipe 823 that connects the inlet 821 and the outlet 822, and an electromagnetic valve 824 attached to the pipe 823. Air A is supplied to the inlet 821 from an external compressor, and when the electromagnetic valve 824 connects the inlet 821 and the outlet 822 (state of FIG. 8A), the air A supplied to the inlet 821 is discharged from the outlet 822 to the mixing area 83, while when the electromagnetic valve 824 blocks the inlet 821 and the outlet 822, the supply of air A from the outlet 822 to the mixing area 83 is stopped. The operation of the solenoid valve 824 is controlled by the control unit 10.

[0043] 8B is a diagram showing a second example of a specific configuration of the air discharge unit. This air discharge unit 82 includes an inlet 821 that takes in air A, an outlet 822 that discharges air A, a pipe 823 that connects the inlet 821 and the outlet 822, and an air pump 825 attached to the pipe 823. When the air pump 825 sends air from the inlet 821 to the outlet 822, the air A sucked from the inlet 821 is discharged from the outlet 822 to the mixing area 83, while when the air pump 825 stops sending air, the supply of air A from the outlet 822 to the mixing area 83 stops. This operation of the air pump 825 is controlled by the control unit 10.

[0044] Next, the maintenance of the ejection head 31 (particularly wiping by the wiper 54) using the above-mentioned maintenance unit 5 and cleaning liquid supply unit 8 will be described. As can be seen from Figs. 3 and 4, the maintenance unit 5 is provided with two wipers 54, and two rows of one wiper 54 and a plurality of ejection heads 31 aligned in the X direction are provided. The wiper 54 wipes the nozzle-facing plane 310 of the ejection head 31 belonging to the same row. Since the wiping operation is common to both wipers 54, the operation of one wiper 54 will be described here.

[0045] Fig. 9 is a flow chart showing an example of maintenance performed on the discharge head, and Fig. 10 is a diagram showing a first example of the operation performed according to the flow chart of Fig. 9. Fig. 10 shows one side X1 and the other side X2 in the X direction. Here, the one side X1 and the other side X2 face in opposite directions. Before describing each step of the flow chart of Fig. 9, the underlying configuration will be described with reference to Fig. 10.

[0046] As described above, the maintenance unit 5 moves in the X direction by being driven by the horizontal drive unit 61. As shown in FIG. 10 in particular, a facing position Pa and a retreat position Pb that are different from each other in the X direction are provided for the maintenance unit 5, and the maintenance unit 5 moves between the facing position Pa and the retreat position Pb. Here, the facing position Pa is a position facing the head unit 3, and the retreat position Pb is a position provided at a distance from the facing position Pa in the X direction. This retreat position Pb is provided on one side X1 of the facing position Pa.

[0047] When the maintenance unit 5 is located at the facing position Pa, the maintenance unit 5 faces the head unit 3 from below, and the multiple caps 52 of the maintenance unit 5 face each of the multiple ejection heads 31 of the head unit 3 from below. On the other hand, when the maintenance unit 5 is located at the retracted position Pb, the maintenance unit 5 retracts in the X direction from the head unit 3. That is, in a plan view, the maintenance unit 5 is located on one side X1 of the head unit 3 in the X direction, and does not overlap the head unit 3.

[0048] Moreover, the above-mentioned cleaning liquid supply unit 8 is disposed on the other side X2 of the head unit 3. As shown in Fig. 10, when the maintenance unit 5 is located at the facing position Pa, the cleaning liquid nozzle 85 of the cleaning liquid supply unit 8 faces the wiper 54 of the maintenance unit 5 from above.

[0049] Furthermore, the printing device 1 includes a flat cover member 63 provided for the retracted position Pb. The cover member 63 and the head unit 3 are aligned in the X direction with a gap therebetween, and the cover member 63 faces the maintenance unit 5 located at the retracted position Pb from above, thereby covering the multiple caps 52 of the maintenance unit 5. When the maintenance unit 5 is located at the retracted position Pb, the wiper 54 of the maintenance unit 5 is located on the other side X2 of the cover member 63 (in other words, between the head unit 3 and the cover member 63).

[0050] As described above, the head unit 3 moves up and down by receiving a driving force from the lifting drive unit 4. That is, the head unit 3 moves up and down in the Z direction between a printing height h0 (FIG. 1), a capping height h1 (FIG. 10), and a wiping height h2 (FIG. 10), which are different from one another. Here, the printing height h0 is a position close to the web W, the wiping height h2 is a position farther away from the web W than the printing height h0, and the capping height h1 is a position farther away from the web W than the printing height h0 and closer to the web W than the wiping height h2.

[0051] Based on the above-mentioned premise configuration, each step of the flowchart in Fig. 9 will be described. Each step in Fig. 9 is executed under the control of the control unit 10. Note that the maintenance in Fig. 9 is executed repeatedly, and it is assumed that foamy cleaning liquid Lb is attached to the wiper 54 of the maintenance unit 5 at the start of the maintenance in Fig. 9. This foamy cleaning liquid Lb is attached to the wiper 54 by executing step S107 described later in the previous maintenance.

[0052] 9, steps S101 to S105 are executed for the ejection heads 31 that are the target of maintenance among the multiple ejection heads 31 of the head unit 3. The target ejection heads 31 may be all or some of the multiple ejection heads 31. In the latter case, for example, an ejection head 31 that has been confirmed to be defective in ejecting ink from the nozzles 311 may be the target of maintenance.

[0053] In step S101, the maintenance unit 5 is positioned at the facing position Pa, and the head unit 3 is positioned at the capping height h1. As a result, the multiple caps 52 of the maintenance unit 5 come into contact with the multiple ejection heads 31 of the head unit 3 from below (capping). Furthermore, the cleaning liquid nozzle 85 faces the wiper 54 of the maintenance unit 5 from above. In this state, the cleaning liquid supply unit 8 executes the rinse mode, and ejects cleaning liquid Lo from the cleaning liquid nozzle 85 onto the wiper 54. This cleaning liquid Lo washes away any deposits (such as foamy cleaning liquid Lb) on the wiper 54.

[0054] In step S102, an ink purge is performed on one of the ejection heads 31 that are the maintenance targets. In this ink purge, ink is caused to flow out of each nozzle 311 of the one ejection head 31. Specifically, ink is sucked from the nozzles 311 of the ejection head 31 by reducing the pressure inside the cap 52 that contacts the ejection head 31. However, the specific method of performing the ink purge is not limited to this, and for example, ink may be pushed out of the nozzles 311 by pressurizing the inside of the ejection head 31.

[0055] When the ink purge in step S102 is completed, the head unit 3 rises from the capping height h1 to the wiping height h2, and the ejection heads 31 are separated from the caps 52 (step S103). This releases the capping of the ejection heads 31 by the caps 52.

[0056] In step S104, wiping is performed on one of the ejection heads 31 to be maintained. In the example of the "Step S104" column in FIG. 10, wiping is performed on one of the three ejection heads 31 arranged in the X direction, at the end of one side X1. In this wiping, the wiper 54 in contact with the nozzle-facing plane 310 of the ejection head 31 is moved in the X direction by the drive of the horizontal drive unit 61, thereby removing the ink that has flowed out by the ink purge from the nozzle-facing plane 310. In this wiping, the wiper 54 may move only to one side in the X direction (for example, one side X1) or may slide back and forth on both sides in the X direction (one side X1 and the other side X2).

[0057] When the wiping in step S104 is completed, the maintenance unit 5 moves to the facing position Pa, and the wiper 54 faces the cleaning liquid nozzle 85 (step S105). Then, it is determined whether the ink purge in step S102 and the wiping in step S104 have been completed for all of the ejection heads 31 to be maintained (step S106). If they have not been completed (if "NO" in step S106), the process returns to step S101, and cleaning liquid Lo is ejected onto the wiper 54 that performed the wiping. This washes away any deposits (ink, etc.) on the wiper 54. On the other hand, if they have been completed (if "YES" in step S106), the process proceeds to step S107.

[0058] In step S107, the cleaning liquid supply unit 8 executes the bubble mode to discharge foamed cleaning liquid Lb from the cleaning liquid nozzle 85 onto the wiper 54. Since the foamed cleaning liquid Lb contains air bubbles, it remains on the wiper 54 for a longer period of time than the cleaning liquid Lo and acts on the ink adhering to the wiper 54.

[0059] When the discharge of the foamy cleaning liquid Lb onto the wiper 54 is completed, the maintenance unit 5 moves to the retreat position Pb (step S108), and the maintenance in Fig. 9 is completed. This makes it possible to start a printing operation in which, for example, the head unit 3 is lowered from the wiping height h2 to the printing height h0 and the head unit 3 discharges ink onto the web W.

[0060] In the embodiment described above, since the foamy cleaning liquid Lb (first cleaning liquid) is supplied to the wiper 54 (wiping member), the foamy cleaning liquid Lb can remove ink from the wiper 54. Moreover, since the wiper 54 contains air bubbles, it can remove ink with a strong cleaning power, and the amount of foamy cleaning liquid Lb required to remove ink can also be reduced.

[0061] Furthermore, the cleaning liquid supply unit 8 selectively supplies one of the foamy cleaning liquid Lb and a cleaning liquid Lo (second cleaning liquid) different from the foamy cleaning liquid Lb to the wiper 54 (steps S101, S107). In this configuration, the wiper 54 can perform various processes other than removing ink with the foamy cleaning liquid Lb.

[0062] In particular, the cleaning liquid Lo does not contain air bubbles. As described above, such cleaning liquid Lo can be used to wash away the foamy cleaning liquid Lb from the wiper 54. That is, since the foamy cleaning liquid Lb contains air bubbles, it does not immediately flow away after being supplied to the wiper 54 and remains on the wiper 54. Therefore, the foamy cleaning liquid Lb can be washed away with the cleaning liquid Lo that does not contain air bubbles, thereby cleaning the wiper 54.

[0063] The cleaning liquid supply unit 8 also has an undiluted liquid discharge unit 81 that supplies cleaning liquid Lo that does not contain bubbles, and an air discharge unit 82 that supplies air A (gas). The cleaning liquid supply unit 8 selectively executes a bubble mode in which foamed cleaning liquid Lb generated by mixing the cleaning liquid Lo supplied from the undiluted liquid discharge unit 81 with air A supplied from the air discharge unit 82 is supplied to the wiper 54, and a rinse mode in which the cleaning liquid Lo supplied from the undiluted liquid discharge unit 81 is supplied to the wiper 54 while the supply of air A from the air discharge unit 82 is stopped. With this configuration, the foamed cleaning liquid Lb and the cleaning liquid Lo can be easily used selectively depending on whether or not air A is mixed with the cleaning liquid Lo (undiluted liquid).

[0064] After the horizontal drive unit 61 performs wiping (step S104), the cleaning liquid supply unit 8 supplies foamy cleaning liquid Lb to the wiper 54 (step S107). Before the horizontal drive unit 61 starts wiping (step S104), the cleaning liquid supply unit 8 supplies cleaning liquid Lo to the wiper 54, thereby removing the foamy cleaning liquid Lb adhering to the wiper 54 from the wiper 54 (step S101). In this configuration, ink adhering to the wiper 54 due to the execution of wiping can be removed from the wiping member by the foamy cleaning liquid Lb. Also, the foamy cleaning liquid Lb remaining on the wiper 54 before the start of wiping can be washed away by the cleaning liquid Lo, and wiping can be performed by a clean wiper 54.

[0065] Fig. 11 is a diagram showing a schematic diagram of a second example of the operation executed according to the flowchart of Fig. 9. Here, the differences from the first example of Fig. 10 will be mainly described, and the common configurations will be denoted by the corresponding reference numerals and the description thereof will be omitted as appropriate. It goes without saying that the common configurations with the first example provide the same effects as the first example. This point is the same for each of the embodiments shown below.

[0066] Compared to the first example in Fig. 10, the position of the cleaning liquid nozzle 85 is different in the second example in Fig. 11. That is, in this second example, the cleaning liquid nozzle 85 is disposed on one side X1 of the head unit 3, more specifically, between the head unit 3 and the cover member 63 in the X direction. The cleaning liquid nozzle 85 thus disposed faces from above the wiper 54 of the maintenance unit 5 located at the retracted position Pb.

[0067] Therefore, in step S101, with the maintenance unit 5 located at the retracted position Pb, the cleaning liquid nozzle 85 executes the rinse mode and discharges the cleaning liquid Lo onto the wiper 54. The cleaning liquid Lo washes away any deposits (such as foamy cleaning liquid Lb) on the wiper 54.

[0068] Subsequently, with the head unit 3 supported at the retraction height h3 by the lifting drive unit 4, the maintenance unit 5 moves from the retracted position Pb to the opposing position Pa. Here, the retraction height h3 is a position spaced apart from the web W by a greater distance than the wiping height h2, and by being positioned at the retraction height h3, the head unit 3 retracts upward from the passage range of the maintenance unit 5 that moves to the opposing position Pa. When the movement of the maintenance unit 5 to the opposing position Pa is completed, the maintenance unit 5 descends from the retraction height h3 to the capping height h1 by the drive of the lifting drive unit 4, and capping is performed.

[0069] Then, ink purging is performed on one of the discharge heads 31 to be maintained (step S102). When the ink purging in step S102 is completed, the head unit 3 rises from the capping height h1 to the wiping height h2, and capping is released (step S103).

[0070] In step S104, wiping is performed on one of the discharge heads 31 to be maintained. When the wiping in step S104 is completed, the maintenance unit 5 moves to the retracted position Pb, and the wiper 54 faces the cleaning liquid nozzle 85 (step S105). Then, it is determined whether the ink purging in step S102 and the wiping in step S104 have been completed for all of the discharge heads 31 to be maintained (step S106). If not completed (when "NO" in step S106), the process returns to step S101, and the cleaning liquid Lo is discharged onto the wiper 54 that has performed wiping. Thereby, the deposits (such as ink) on the wiper 54 are washed away. On the other hand, if completed (when "YES" in step S106), the process proceeds to step S107.

[0071] In step S107, the cleaning liquid supply unit 8 executes the bubble mode to discharge foamed cleaning liquid Lb from the cleaning liquid nozzle 85 onto the wiper 54. Since the foamed cleaning liquid Lb contains air bubbles, it remains on the wiper 54 for a longer period of time than the cleaning liquid Lo and acts on the ink adhering to the wiper 54.

[0072] 9 ends with the maintenance unit 5 positioned at the retreated position Pb (step S108). This makes it possible to start a printing operation in which the head unit 3 ejects ink from the head unit 3 onto the web W by lowering the head unit 3 from the wiping height h2 to the printing height h0, for example.

[0073] In this embodiment as well, foamy cleaning liquid Lb (first cleaning liquid) is supplied to the wiper 54 (wiping member), so that the foamy cleaning liquid Lb can remove ink from the wiper 54. Moreover, since the wiper 54 contains air bubbles, it can remove ink with strong cleaning power, and the amount of foamy cleaning liquid Lb required to remove ink can also be reduced.

[0074] Furthermore, the cleaning liquid supply unit 8 selectively supplies one of the foamy cleaning liquid Lb and a cleaning liquid Lo (second cleaning liquid) different from the foamy cleaning liquid Lb to the wiper 54 (steps S101, S107). In this configuration, the wiper 54 can perform various processes other than removing ink with the foamy cleaning liquid Lb.

[0075] In particular, the cleaning liquid Lo does not contain air bubbles. As described above, such cleaning liquid Lo can be used to wash away the foamy cleaning liquid Lb from the wiper 54. That is, since the foamy cleaning liquid Lb contains air bubbles, it does not immediately flow away after being supplied to the wiper 54 and remains on the wiper 54. Therefore, the foamy cleaning liquid Lb can be washed away with the cleaning liquid Lo that does not contain air bubbles, thereby cleaning the wiper 54.

[0076] As described above, in this embodiment, the printing device 1 corresponds to an example of the "printing device" of the present invention, the ejection head 31 corresponds to an example of the "ejection head" of the present invention, the nozzle-facing plane 310 corresponds to an example of the "ink ejection surface" of the present invention, the nozzle 311 corresponds to an example of the "nozzle" of the present invention, the wiper 54 corresponds to an example of the "wiping member" of the present invention, the horizontal drive unit 61 corresponds to an example of the "drive unit" of the present invention, the cleaning liquid supply unit 8 corresponds to an example of the "cleaning liquid supply unit" of the present invention, the concentrate ejection unit 81 corresponds to an example of the "concentrate liquid supply unit" of the present invention, the air ejection unit 82 corresponds to an example of the "gas supply unit" of the present invention, the air A corresponds to an example of the "gas" of the present invention, the foamy cleaning liquid Lb corresponds to an example of the "first cleaning liquid" of the present invention, and the cleaning liquid Lo corresponds to an example of the "second cleaning liquid" of the present invention.

[0077] The present invention is not limited to the above-mentioned embodiment, and various modifications can be made without departing from the spirit of the present invention. For example, the specific configuration of the cleaning liquid supply unit 8 may be changed. FIG. 12 is a diagram showing a schematic configuration of a second example of the cleaning liquid supply unit. The second example of FIG. 12 differs from the first example of FIG. 5 in that an air stone 831 is arranged in the mixing region 83.

[0078] In the "bubble mode", when the raw liquid discharge part 81 discharges the cleaning liquid Lo while the air discharge part 82 discharges air, the cleaning liquid Lo discharged from the raw liquid discharge part 81 and the air discharged from the air discharge part 82 are mixed in the mixing area 83. At this time, the air A finely divided by the air stone 831 is mixed with the cleaning liquid Lo, and a foamed cleaning liquid Lb (= cleaning liquid Lo + air A) containing fine bubbles is generated. Then, this foamed cleaning liquid Lb is discharged from the opening 851 of the cleaning liquid nozzle 85. Also, in the "rinse mode", when the raw liquid discharge part 81 discharges the cleaning liquid Lo with the air discharge part 82 stopping the air discharge, the cleaning liquid Lo discharged from the raw liquid discharge part 81 flows into the cleaning liquid nozzle 85 via the air stone 831 in the mixing area 83 and is discharged from the cleaning liquid nozzle 85. That is, also in the second example, the cleaning liquid supply unit 8 executes the bubble mode to eject foamy cleaning liquid Lb containing air bubbles from the cleaning liquid nozzle 85, and executes the rinse mode to eject cleaning liquid Lo not containing air bubbles from the cleaning liquid nozzle 85.

[0079] Alternatively, instead of the air stone 831, a microbubble generator that generates microbubbles or a nanobubble generator that generates nanobubbles may be provided, and a foamy cleaning liquid Lb containing microbubbles or nanobubbles may be discharged from the cleaning liquid nozzle 85 in the bubble mode, while a cleaning liquid Lo that does not contain bubbles may be discharged from the cleaning liquid nozzle 85 in the rinse mode.

[0080] 13 is a diagram showing a schematic configuration of a third example of the cleaning liquid supply unit. In the third example of the cleaning liquid supply unit 8, two pipes 861 and 862 are provided in parallel, and each of the pipes 861 and 862 communicates with a cleaning liquid nozzle 85. Of the pipes 861 and 862, a bubble generating unit 87 is attached to the pipe 861. The bubble generating unit 87 has a plurality of mesh filters 871 arranged in series, and bubbles are generated when the cleaning liquid Lo passes through the mesh filters 871. In addition, an electromagnetic valve 88 is provided between the pipes 861 and 862 and the stock solution discharge unit 81, and the electromagnetic valve 88 switches the connection destination of the stock solution discharge unit 81 between the pipes 861 and 862.

[0081] In the bubble mode, the solenoid valve 88 connects the stock solution discharge part 81 to the pipe 861 and blocks the stock solution discharge part 81 from the pipe 862. Therefore, the cleaning solution Lo discharged from the stock solution discharge part 81 flows into the air bubble generation part 87, and the cleaning solution Lo containing bubbles, i.e., the foamy cleaning solution Lb, is generated in the air bubble generation part 87. The foamy cleaning solution Lb thus generated flows from the air bubble generation part 87 into the cleaning solution nozzle 85 and is discharged from the cleaning solution nozzle 85.

[0082] In the rinse mode, the solenoid valve 88 connects the undiluted liquid discharge part 81 to the pipe 862 and blocks the undiluted liquid discharge part 81 from the pipe 861. Therefore, the cleaning liquid Lo discharged from the undiluted liquid discharge part 81 bypasses the air bubble generation part 87 and is discharged from the cleaning liquid nozzle 85.

[0083] In the above embodiment, two types of liquid, foamy cleaning liquid Lb and cleaning liquid Lo, are discharged from the cleaning liquid supply unit 8 to the wiper 54. However, it is also possible to configure so that two types of foamy cleaning liquid Lb having different bubble states are discharged to the wiper 54. Fig. 14 is a diagram showing, in the form of a table, the operation of discharging two types of foamy cleaning liquid by the cleaning liquid supply unit in Fig. 5.

[0084] As shown in FIG. 14, in the "first bubble mode", the air discharge part 82 discharges air A at a speed V1 (flow speed) while the raw liquid discharge part 81 discharges the cleaning liquid Lo, thereby generating a foamed cleaning liquid Lb1 containing air bubbles. In the "second bubble mode", the air discharge part 82 discharges air A at a speed V2 (flow speed) while the raw liquid discharge part 81 discharges the cleaning liquid Lo, thereby generating a foamed cleaning liquid Lb2. Here, the speed V1 is faster than the speed V2. Therefore, the air bubbles contained in the foamed cleaning liquid Lb1 are finer (i.e., have a smaller diameter) than the air bubbles contained in the foamed cleaning liquid Lb2. In addition, when performing the maintenance shown in FIG. 9, the first bubble mode can be performed instead of the bubble mode, and the second bubble mode can be performed instead of the rinse mode.

[0085] In this configuration, foamy cleaning liquid Lb1 (first cleaning liquid) and foamy cleaning liquid Lb2 (second cleaning liquid) having different bubble states can be supplied to the wiper 54. Therefore, a variety of processes can be performed on the wiper 54.

[0086] Specifically, the size (diameter) of the bubbles contained in the foamy cleaning liquid Lb2 is larger than the size (diameter) of the bubbles contained in the foamy cleaning liquid Lb1. The coarse bubbles of the foamy cleaning liquid Lb2 tend to disappear faster than the fine bubbles of the foamy cleaning liquid Lb1. Therefore, for example, in step S101 of FIG. 9, the foamy cleaning liquid Lb2 can be used to wash away the foamy cleaning liquid Lb1 from the wiper 54. That is, since the bubbles contained in the foamy cleaning liquid Lb1 are fine, the foamy cleaning liquid Lb1 does not flow immediately after being supplied to the wiper 54 in step S107 but remains on the wiper 54. In contrast, since the bubbles contained in the foamy cleaning liquid Lb2 are coarse, the foamy cleaning liquid Lb2 flows quickly after being supplied to the wiper 54. Therefore, the foamy cleaning liquid Lb1 can be washed away with the foamy cleaning liquid Lb2 to clean the wiper 54.

[0087] 5, the cleaning liquid supply unit 8 has an original liquid discharge unit 81 that supplies cleaning liquid Lo that does not contain bubbles, and an air discharge unit 82 that supplies air A. The cleaning liquid supply unit 8 changes the speed at which the air A discharged from the air discharge unit 82 is mixed with the cleaning liquid Lo discharged from the original liquid discharge unit 81, thereby selectively generating foamed cleaning liquid Lb1 and foamed cleaning liquid Lb2 having different bubble states, and discharging them onto the wiper 54. In this configuration, the foamed cleaning liquid Lb1 and the foamed cleaning liquid Lb2 can be easily used selectively by changing the speed at which the air A is mixed with the cleaning liquid Lo (original liquid).

[0088] Although the above describes a mode in which the cleaning liquid is discharged onto the wiper 54, the cleaning liquid nozzle 85 may also discharge the cleaning liquid onto a member other than the wiper 54. Fig. 15A is a schematic diagram of the wiper 54 and the wiper lifting mechanism 55 as viewed from the Y direction. The cleaning liquid nozzle 85 may discharge the cleaning liquid onto the wiper lifting mechanism 55 as well as onto the wiper 54.

[0089] The wiper lifting mechanism 55 is L-shaped when viewed in the Y direction and includes a wiper fixing bracket 55a that fixes the wiper 54 at its upper and lower pieces, a bolt 55b that screws the wiper 54 into the wiper fixing bracket 55a, and a cam 55c that abuts the lower side of the horizontal piece of the wiper fixing bracket 55a. The cam 55c is disposed in the waste liquid container 513 and rotated in the Y direction by a motor (not shown). This causes the wiper 54, the wiper fixing bracket 55a, and the bolt 55b to be lifted and lowered in the Z direction.

[0090] The cleaning liquid nozzle 85 can discharge the cleaning liquid to the wiper 54 and the wiper lifting mechanism 55 in either a bubble mode or a rinse mode (see FIG. 6), or a first bubble mode or a second bubble mode (see FIG. 14).

[0091] Here, the thickness of the layer of foamy cleaning liquid Lb attached to the wiper 54, the wiper fixing metal fitting 55a, and the bolt 55 can be changed in the X direction. In Fig. 15A, the symbol Re indicates the X direction region of the bolt 55b and the wiper fixing metal fitting 55a, and the symbol Rm indicates the X direction region of the wiper 54. The region Re is defined as both end regions Re, and the region Rm between the both end regions Re is defined as the central region Rm.

[0092] In the example of FIG. 15A, the layer of foamy cleaning liquid Lb formed in both end regions Re is made thicker than the layer of foamy cleaning liquid Lb formed in the central region Rm.

[0093] 15A can be achieved by making the speed at which the wiper 54 and the wiper fixing metal fitting 55a move in the X direction relative to the cleaning liquid nozzle 85 during the period when the foamed cleaning liquid Lb is discharged from the cleaning liquid nozzle 85 to the both end regions Re slower than the speed at which the wiper 54 and the wiper fixing metal fitting 55a move in the X direction relative to the cleaning liquid nozzle 85 during the period when the foamed cleaning liquid Lb is discharged from the cleaning liquid nozzle 85 to the central region Rm. This state is suitable, for example, when there is significant adhesion of ink to the both end regions Re.

[0094] In the example of Fig. 15B, the thickness of the layer of foamy cleaning liquid Lb formed in both end regions Re is thinner than the thickness of the layer of foamy cleaning liquid Lb formed in the central region Rm between both end regions Re. Specifically, the speed at which the wiper 54 and the wiper fixing metal fitting 55a move in the X direction relative to the cleaning liquid nozzle 85 during the period when the foamy cleaning liquid Lb is discharged from the cleaning liquid nozzle 85 to both end regions Re is made faster than the speed at which the wiper 54 and the wiper fixing metal fitting 55a move in the X direction relative to the cleaning liquid nozzle 85 during the period when the foamy cleaning liquid Lb is discharged from the cleaning liquid nozzle 85 to the central region Rm, thereby forming the state of Fig. 15B. This state is suitable, for example, when there is significant adhesion of ink in the central region Rm.

[0095] In this manner, in a state where the foamed cleaning liquid Lb is supplied from the cleaning liquid nozzle 85 to the wiper 54 and the wiper fixing metal fitting 55a, the horizontal drive unit 61 changes the speed at which the wiper 54 moves relative to the cleaning liquid nozzle 85, thereby changing the thickness of the foamed cleaning liquid Lb adhering to the wiper 54 and the wiper fixing metal fitting 55a. In this configuration, an appropriate thickness of the foamed cleaning liquid Lb can be made to adhere to the wiper 54 and the wiper fixing metal fitting 55a, and ink can be removed from the wiper 54 and the wiper fixing metal fitting 55a. Note that the movement of the wiper 54 and the wiper fixing metal fitting 55a relative to the cleaning liquid nozzle 85 is not limited to the driving of the wiper 54 and the wiper fixing metal fitting 55a, and may be performed by driving the cleaning liquid nozzle 85. In short, it is only necessary to move the wiper 54 and the wiper fixing metal fitting 55a relative to the cleaning liquid nozzle 85.

[0096] The method of changing the thickness of the layer of the foamy cleaning liquid Lb is not limited to the above. For example, the amount of cleaning liquid supplied from the cleaning liquid nozzle 85 to the both end regions Re and the central region Rm can be made different to change the thickness of the layer of the foamy cleaning liquid Lb adhering to these regions. In this case, the moving speed of the cleaning liquid nozzle 85 relative to the wiper 54 and the wiper fixing metal fitting 55a may be constant. Alternatively, the moving speed of the cleaning liquid nozzle 85 during the period of moving through the both end regions Re may be made slower than the moving speed during the period of moving through the central region Rm.

[0097] Furthermore, the thickness of the layer of the foamed cleaning liquid Lb may be changed in the X direction by varying the composition of the cleaning liquid discharged from the cleaning nozzle 85 in the X direction.

[0098] For example, foamy cleaning liquid Lb2 is discharged from the cleaning nozzle 85 to both end regions Re. Since the foamy cleaning liquid Lb2 contains many large bubbles, it adheres to both end regions Re in a state of having a large layer thickness. At this time, it is preferable that the cleaning nozzle 85 discharges the foamy cleaning liquid Lb2 while being stopped relative to the wiper fixing metal fitting 55a.

[0099] On the other hand, foamy cleaning liquid Lb1 is discharged from the cleaning nozzle 85 to the central region Rm. The size of the bubbles contained in the foamy cleaning liquid Lb1 is smaller than the size of the bubbles contained in the foamy cleaning liquid Lb2. Therefore, the foamy cleaning liquid Lb1 adheres to the central region Rm with a relatively small layer thickness. At this time, it is preferable that the cleaning nozzle 85 discharges the foamy cleaning liquid Lb1 while remaining stationary relative to the wiper 54, but the foamy cleaning liquid Lb1 may be discharged while moving.

[0100] Alternatively, cleaning liquid with a thin foam may be applied to both end regions Re, and cleaning liquid with a thick foam may be applied to the central region Rm. In this case, foamy cleaning liquid Lb1 may be discharged from the cleaning nozzle 85 to both end regions Re, and foamy cleaning liquid Lb2 may be discharged from the cleaning nozzle 85 to the central region Rm.

[0101] Furthermore, the movement of the wiper 54 relative to the head unit 3 for wiping is not limited to driving the wiper 54, and may be performed by driving the head unit 3. In short, it is sufficient if the wiper 54 can be moved relatively to the head unit 3.

[0102] 9 may be modified as appropriate. For example, step S101 of discharging the cleaning liquid Lo onto the wiper 54 is not essential. That is, if the foamed cleaning liquid Lb discharged onto the wiper 54 in step S107 is easily foamed, step S101 is not necessary. In this case, the cleaning liquid supply unit 8 does not need to be able to discharge the cleaning liquid Lo onto the wiper 54, and it is sufficient if it is able to discharge only the foamed cleaning liquid Lb. [Industrial Applicability]

[0103] The present invention is applicable to all techniques for cleaning wiping members that wipe the ink ejection surface of an ejection head that ejects ink from nozzles provided on the ink ejection surface. [Explanation of symbols]

[0104] 1...Printing device 31...Discharge head 310...Nozzle facing surface (ink ejection surface) 311…Nozzle 54...Wiper (wiping member) 61...Horizontal drive unit (drive unit) 8…Cleaning liquid supply section 81...Standard solution discharge section (stock solution supply section) 82...Air discharge section (gas supply section) A…Air (gas) Lb…Foam cleaning solution (first cleaning solution) Lo…Cleaning solution (second cleaning solution)

Claims

1. an ejection head that ejects ink from nozzles provided on an ink ejection surface; a wiping member for wiping off ink adhering to the ink ejection surface; a drive unit that performs wiping by moving the wiping member that contacts the ink ejection surface relative to the ejection head; a cleaning liquid supply unit that supplies a first cleaning liquid containing air bubbles to the wiping member; Equipped with The cleaning liquid supply unit has a cleaning liquid nozzle that ejects the first cleaning liquid, and supplies the first cleaning liquid to the wiping member by ejecting the first cleaning liquid from the cleaning liquid nozzle that faces the wiping member after the wiping of the ejection head is completed.

2. An ejection head that ejects ink from nozzles provided on an ink ejection surface; a wiping member for wiping off ink adhering to the ink ejection surface; a drive unit that performs wiping by moving the wiping member that contacts the ink ejection surface relative to the ejection head; a cleaning liquid supply unit that supplies a first cleaning liquid containing air bubbles to the wiping member; Equipped with The cleaning liquid supply unit selectively supplies one of the first cleaning liquid and a second cleaning liquid different from the first cleaning liquid to the wiping member.

3. The printing apparatus according to claim 2 , wherein the second cleaning liquid does not contain air bubbles.

4. 4. The printing device according to claim 3, wherein the cleaning liquid supply unit has an original liquid supply unit which supplies cleaning liquid not containing air bubbles, and a gas supply unit which supplies gas, and supplies the first cleaning liquid generated by mixing the cleaning liquid supplied from the original liquid supply unit with the gas supplied from the gas supply unit to the wiping member, and supplies the cleaning liquid supplied from the original liquid supply unit as the second cleaning liquid to the wiping member while the supply of gas from the gas supply unit is stopped.

5. the second cleaning liquid contains air bubbles; The printing apparatus according to claim 2 , wherein a state of air bubbles contained in the first cleaning liquid is different from a state of air bubbles contained in the second cleaning liquid.

6. The printing apparatus according to claim 5 , wherein the size of the air bubbles contained in the second cleaning liquid is larger than the size of the air bubbles contained in the first cleaning liquid.

7. 7. The printing device according to claim 5, wherein the cleaning liquid supply unit has a stock liquid supply unit which supplies cleaning liquid not containing air bubbles, and a gas supply unit which supplies gas, and by changing a speed at which the cleaning liquid supplied from the stock liquid supply unit is mixed with the gas supplied from the gas supply unit, the first cleaning liquid and the second cleaning liquid having different air bubble states are selectively generated and supplied to the wiping member.

8. After the driving unit performs the wiping, the cleaning liquid supply unit supplies the first cleaning liquid to the wiping member, A printing device as described in any one of claims 2 to 7, wherein before the drive unit starts the wiping, the cleaning liquid supply unit supplies the second cleaning liquid to the wiping member, thereby removing the first cleaning liquid adhering to the wiping member from the wiping member.

9. An ejection head that ejects ink from nozzles provided on an ink ejection surface; a wiping member for wiping off ink adhering to the ink ejection surface; a drive unit that performs wiping by moving the wiping member that contacts the ink ejection surface relative to the ejection head; a cleaning liquid supply unit that supplies a first cleaning liquid containing air bubbles to the wiping member; Equipped with A printing device in which, while the first cleaning liquid is supplied from the cleaning liquid supply unit to the wiping member, a thickness of the first cleaning liquid adhering to the wiping member is changed by changing the speed at which the drive unit moves the wiping member relative to the cleaning liquid supply unit.

10. a wiping step of moving a wiping member relative to an ejection head that ejects ink from nozzles provided on an ink ejection surface while bringing the wiping member into contact with the ejection head; a step of supplying a first cleaning liquid containing air bubbles to the wiping member by a cleaning liquid supplying unit; Equipped with The cleaning liquid supply unit has a cleaning liquid nozzle that ejects the first cleaning liquid, and the method for cleaning a wiping member supplies the first cleaning liquid to the wiping member by ejecting the first cleaning liquid from the cleaning liquid nozzle facing the wiping member after the wiping of the ejection head is completed.

Images