JP7682066B2 - Printing device and wiping member cleaning method - Google Patents

Description

This invention relates to a technology 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.

In an ejection head that ejects ink from nozzles, it is necessary to remove ink that has adhered to the ejection head. Therefore, the technology described in Patent Document 1 removes the ink by supplying a cleaning liquid to the ejection head. In addition, the technology described in Patent Document 2 removes the ink by supplying a cleaning liquid to the ejection head and then wiping the ejection head with a wiping member.

Japanese Patent Application Publication No. 11-198396 JP 2016-155252 A

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 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.

This invention has been developed in consideration of the above problems, and aims 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.

The printing device according to 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 that contacts 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.

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

In the present invention (printing device, wiping member cleaning method) configured in this way, 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, because the first cleaning liquid contains air bubbles, it can remove ink with a strong cleaning power, and the amount of first cleaning liquid required to remove ink can also be reduced.

The printing device may also 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 can be performed on the wiping member other than removing ink with the first cleaning liquid.

The second cleaning liquid may have a variety of specific compositions. For example, a second cleaning liquid that does not contain air bubbles may be supplied to the wiping member. Such a second cleaning liquid may be used, for example, to wash away the first cleaning liquid from the wiping member. In other words, since the first cleaning liquid contains air bubbles, it does not flow immediately after being supplied to the wiping member, but 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, thereby cleaning the wiping member.

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 air 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).

Alternatively, a second cleaning liquid containing air bubbles may be supplied to the wiping member. In this case, by differentiating the state of the air bubbles contained in the first cleaning liquid from the state of the air bubbles contained in the second cleaning liquid, a variety of processes can be performed on the wiping member.

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.

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).

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 begins, the first cleaning liquid remaining on the wiping member can be washed away by the second cleaning liquid, and wiping can be performed with a clean wiping member.

The printing device may also be configured so that, while the first cleaning liquid is being 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. In this configuration, an appropriate thickness of first cleaning liquid can be applied to the wiping member to remove ink from the wiping member.

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 an ejection head that ejects ink from nozzles provided on the ink ejection surface.

FIG. 1 is a front view showing an example of a printing apparatus according to an embodiment of the present invention. FIG. 2 is a block diagram showing an electrical configuration of the printing apparatus shown in FIG. 1 . FIG. 2 is a bottom view illustrating a schematic configuration of the head unit. FIG. 2 is a perspective view illustrating a configuration of a maintenance unit. FIG. 2 is a diagram illustrating a configuration of a first example of a cleaning liquid supply unit. 6 is a diagram showing the operation of the cleaning liquid supply unit in FIG. 5 in the form of a table. FIG. 2 is a diagram showing a first example of a specific configuration of a concentrate discharge portion. FIG. 11 is a diagram showing a second example of a specific configuration of the concentrate discharge portion. FIG. 4 is a diagram illustrating a first example of a specific configuration of an air discharge portion. FIG. 11 is a diagram showing a second example of a specific configuration of the air ejection portion. 6 is a flowchart showing an example of maintenance performed on the ejection head. FIG. 10 is a diagram illustrating a first example of the operation executed according to the flowchart of FIG. 9 . FIG. 10 is a diagram illustrating a second example of the operation executed according to the flowchart of FIG. 9 . FIG. 11 is a diagram illustrating a configuration of a second example of a cleaning liquid supply unit. FIG. 13 is a diagram illustrating a configuration of a third example of a cleaning liquid supply unit. 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 . 5 is a schematic diagram of the wiper 54 and the wiper lifting mechanism 55 as viewed from the Y direction. 5 is a schematic diagram of the wiper 54 and the wiper lifting mechanism 55 as viewed from the Y direction.

Figure 1 is a front view showing a schematic example of a printing device according to the present invention, and Figure 2 is a block diagram showing the electrical configuration of the printing device of Figure 1. In Figure 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 using 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 is equipped with a control unit 10 that provides overall control of the entire device, and the control required for printing and maintenance is performed by the control unit 10.

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

The printing device 1 also includes a display 14, which may be, for example, an LCD 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 realized by input devices such as a keyboard or mouse that are provided separately from the display 14.

The printing device 1 includes a transport unit 2 that transports the web W. The transport unit 2 includes a feed roller 21 and a take-up roller 22, and transports the web W roll-to-roll by winding up the web W unwound by the feed roller 21 with the take-up roller 22. The transport unit 2 includes an intake unit 23 between the feed roller 21 and the take-up roller 22 that takes in the web W unwound from the feed roller 21. The intake unit 23 includes two drive rollers 231, two nip rollers 232, and an edge position adjustment unit 234 provided between the two drive rollers 231. Each drive roller 231 rotates by the driving force of a motor while wrapping 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.

The transport section 2 also has a number 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 from below onto which ink is ejected by the inkjet method. In particular, the support rollers 24 are arranged at an incline so that the support rollers 24 on the downstream side of 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 that it rises as it approaches the Y direction.

The conveying section 2 further includes 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 includes 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 further includes 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 further includes a drive roller 281 and a nip roller 282 that are disposed between the support rollers 27 and the winding roller 22. The drive roller 281 drives the web W by rotating by the driving force of the motor while wrapping the web W around it. The nip roller 282 sandwiches the web W between the drive roller 281 and the nip roller 282.

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 the configuration of the head unit. The head unit 3 has a plurality of (five) ejection heads 31. The plurality of ejection heads 31 are arranged in two rows in a staggered pattern in the X direction. In other words, a head column C31 consisting of three ejection heads 31 arranged parallel to the X direction and a head column 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 and face the web W from above, and each nozzle 311 ejects ink onto 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 number of head insertion holes 321 provided corresponding to the number of ejection heads 31, and the multiple ejection heads 31 are fixed to the head holding member 32 while being 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.

As shown in FIG. 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 head units 3 are arranged so 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 be 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.

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 commands 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.

The printing device 1 also includes a number of lifting and lowering drive units 4 each corresponding to a number of head units 3. Each lifting and lowering drive unit 4 raises or lowers 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 number of positions at different heights. In FIG. 1, each head unit 3 is positioned at a printing height h0 that is closest to the web W. Such a lifting and lowering drive unit 4 can be realized by a known specific configuration, and can be configured to raise and lower the head unit 3 by driving, for example, a ball screw or an eccentric cam with a motor.

The printing device 1 further 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 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 of the head unit 3, which will be described later. 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 a 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, the details of the maintenance unit 5 will be explained.

Figure 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 tilted in accordance with the tilt of the head unit 3. However, since the tilt of the maintenance unit 5 is slight, the tilt of the maintenance unit 5 is not reflected in Figure 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 explanation will focus on one maintenance unit 5.

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

The maintenance unit 5 also has a cap 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 that drops from the ejection head 31. The multiple caps 52 are arranged in two staggered rows 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.

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 when viewed 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 when viewed from the top. This seal member 53 is made of an elastic material 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 of the base member 51.

The maintenance unit 5 also has a wiper 54 made of an elastic material that elastically deforms, such as rubber or silicone. 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 wipers 54 are 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). Thus, at the upstream end of the base member 51 in the X direction, multiple (two) wipers 54 are arranged in the Y direction. Each wiper 54 scrapes off ink from the nozzle-facing plane 310 of the ejection head 31, as described below.

The maintenance unit 5 further 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. A waste liquid container 513 is inserted into each tank mounting portion 512. Thus, 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.

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.

Figure 5 is a diagram showing a schematic configuration of a first example of the cleaning liquid supply unit, and Figure 6 is a diagram showing the operation of the cleaning liquid supply unit of Figure 5 in the form of a table. This cleaning liquid supply unit 8 has a raw liquid discharge unit 81 that discharges cleaning liquid Lo (raw liquid), an air discharge unit 82 that discharges air A, a pipe 841 that guides the cleaning liquid Lo discharged from the raw liquid discharge unit 81 to the mixing area 83, a pipe 842 that guides the air A discharged from the air discharge unit 82 to the mixing area 83, and a cleaning liquid nozzle 85 that communicates with the mixing area 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.

As shown in the "bubble mode" of FIG. 6, when the stock solution discharge unit 81 discharges the cleaning solution Lo while the air discharge unit 82 discharges air, the cleaning solution Lo discharged from the stock solution discharge unit 81 and the air discharged from the air discharge unit 82 are mixed in the mixing area 83. As a result, the bubbly air A is mixed with the cleaning solution Lo to generate a bubbly cleaning solution Lb (= cleaning solution Lo + air A) containing air bubbles. Then, this bubbly cleaning solution Lb is discharged from the opening 851 of the cleaning solution nozzle 85. Also, as shown in the "rinse mode" of FIG. 6, when the stock solution discharge unit 81 discharges the cleaning solution Lo with the air discharge unit 82 stopping air discharge, the cleaning solution Lo discharged from the stock solution discharge unit 81 flows into the cleaning solution nozzle 85 through the mixing area 83 and is discharged from the cleaning solution 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 that does not contain air bubbles from the cleaning liquid nozzle 85 by executing the rinse mode.

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 the cleaning solution Lo. The syringe 811 has a barrel 811b and a plunger 811p fitted into 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. In addition, 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 allows 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. The barrel 811b is also connected to the outlet 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 allows the cleaning solution Lo to flow from the barrel 811b to the outlet 816, but prohibits the cleaning solution Lo from flowing from the outlet 816 to the barrel 811b.

In the concentrate discharge unit 81, when the actuator 812a moves the plunger 811p in a direction to pull it out of the barrel 811b (to the left in FIG. 7A), the cleaning liquid Lo flowing out from the cleaning liquid tank 813 fills the barrel 811b. When the actuator 812a moves the plunger 811p in a direction to push it 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 area 83. This operation of the actuator 812a is controlled by the control unit 10.

Figure 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 Figure 7A has a cleaning solution tank 813 that stores the cleaning solution Lo, a pipe 819 that connects the stock solution discharge unit 81 to the outlet 816, 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 then delivered from the outlet 816 to the mixing area 83. This operation of the liquid delivery pump 812p is controlled by the control unit 10.

In addition, 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 intake port 821 that takes in air A, an outlet port 822 that discharges air A, a pipe 823 that connects the intake port 821 and the outlet port 822, and an electromagnetic valve 824 attached to the pipe 823. Air A is supplied to the intake port 821 from an external compressor, and when the electromagnetic valve 824 connects the intake port 821 and the outlet port 822 (state of FIG. 8A), the air A supplied to the intake port 821 is discharged from the outlet port 822 to the mixing area 83, while when the electromagnetic valve 824 blocks the intake port 821 and the outlet port 822, the supply of air A from the outlet port 822 to the mixing area 83 is stopped. This operation of the solenoid valve 824 is controlled by the control unit 10.

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

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 Figures 3 and 4, the maintenance unit 5 is provided with two wipers 54, and two rows of one wiper 54 and multiple ejection heads 31 aligned in the X direction are provided. The wiper 54 then wipes the nozzle-facing plane 310 of the ejection head 31 belonging to the same row. Note that the wiping operation is common to both wipers 54, so the operation of one wiper 54 will be described here.

Fig. 9 is a flowchart showing an example of maintenance performed on a discharge head, and Fig. 10 is a diagram showing a first example of the operation performed according to the flowchart of Fig. 9. In Fig. 10, one side X1 and the other side X2 in the X direction are shown. Here, one side X1 and the other side X2 face in opposite directions. Before explaining each step of the flowchart of Fig. 9, the underlying configuration will be explained using Fig. 10.

As described above, the maintenance unit 5 moves in the X direction by being driven by the horizontal drive unit 61. As shown in particular in FIG. 10, the maintenance unit 5 is provided with an opposing position Pa and a retracted position Pb that are different from each other in the X direction, and the maintenance unit 5 moves between the opposing position Pa and the retracted position Pb. Here, the opposing position Pa is a position facing the head unit 3, and the retracted position Pb is a position spaced apart from the opposing position Pa in the X direction. This retracted position Pb is provided on one side X1 of the opposing position Pa.

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 from the head unit 3 in the X direction. In other words, 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.

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 opposing 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.

The printing device 1 further 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).

As described above, the head unit 3 rises and falls upon receiving a driving force from the lift drive unit 4. That is, the head unit 3 rises and falls between the printing height h0 (FIG. 1), the capping height h1 (FIG. 10), and the wiping height h2 (FIG. 10), which are different from one another in the Z direction. 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.

Based on the above 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 at the start of the maintenance in FIG. 9, foamy cleaning liquid Lb is attached to the wiper 54 of the maintenance unit 5. This foamy cleaning liquid Lb has been attached to the wiper 54 by executing step S107 described below during the previous maintenance.

According to the flowchart in FIG. 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 of the multiple ejection heads 31, or just some of them. In the latter case, for example, an ejection head 31 that has been confirmed to be failing to eject ink from the nozzles 311 may be the target of maintenance.

In step S101, the maintenance unit 5 is positioned at the opposing 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 contact 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 (foamy cleaning liquid Lb, etc.) on the wiper 54.

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 ejection head 31. Specifically, ink is sucked out of 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.

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 head 31 and the cap 52 are separated (step S103). This releases the capping of the ejection head 31 by the cap 52.

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 ink that has flowed out due to 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).

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 adhering matter (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.

In step S107, the cleaning liquid supply unit 8 executes the bubble mode to eject foamed cleaning liquid Lb from the cleaning liquid nozzle 85 onto the wiper 54. This foamed cleaning liquid Lb contains air bubbles, so 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.

When the ejection of the foam cleaning liquid Lb onto the wiper 54 is complete, the maintenance unit 5 moves to the retreat position Pb (step S108), and the maintenance in FIG. 9 is completed. This allows, for example, the head unit 3 to be lowered from the wiping height h2 to the printing height h0, and a printing operation can be started in which ink is ejected from the head unit 3 onto the web W.

In the embodiment described above, 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 a strong cleaning power, and the amount of foamy cleaning liquid Lb required to remove ink can also be reduced.

The cleaning liquid supply unit 8 also selectively supplies the wiper 54 with either the foamy cleaning liquid Lb or a cleaning liquid Lo (second cleaning liquid) different from the foamy cleaning liquid Lb (steps S101 and S107). With this configuration, the wiper 54 can perform various processes other than removing ink with the foamy cleaning liquid Lb.

In particular, the cleaning liquid Lo does not contain air bubbles. As described above, such cleaning liquid Lo can be used to rinse the foamy cleaning liquid Lb from the wiper 54. In other words, since the foamy cleaning liquid Lb contains air bubbles, it does not flow immediately after being supplied to the wiper 54 and remains on the wiper 54. Therefore, the foamy cleaning liquid Lb can be rinsed away with the cleaning liquid Lo that does not contain air bubbles, thereby cleaning the wiper 54.

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 depending on whether or not air A is mixed with the cleaning liquid Lo (undiluted liquid).

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). Then, 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.

Figure 11 is a diagram showing a schematic diagram of a second example of the operation executed according to the flowchart of Figure 9. Here, the differences from the first example of Figure 10 will be mainly described, and the common configuration will be given the corresponding reference numerals and the description will be omitted as appropriate. It goes without saying that the common configuration with the first example provides the same effect as the first example. This point is the same for each of the embodiments shown below.

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 in the retracted position Pb.

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

Next, with the head unit 3 supported at the retraction height h3 by the lift drive unit 4, the maintenance unit 5 moves from the retraction position Pb to the opposing position Pa. Here, the retraction height h3 is a position farther away from the web W than the wiping height h2, and by being positioned at the retraction height h3, the head unit 3 retracts upward out of the passing range of the maintenance unit 5 moving to the opposing position Pa. Once the movement of the maintenance unit 5 to the opposing position Pa is complete, the maintenance unit 5 is lowered from the retraction height h3 to the capping height h1 by the drive of the lift drive unit 4, and capping is performed.

Then, ink purging is performed on one of the ejection heads 31 that are the maintenance targets (step S102). When the ink purging in step S102 is completed, the head unit 3 is raised from the capping height h1 to the wiping height h2, and the capping is released (step S103).

In step S104, wiping is performed on one of the ejection heads 31 to be maintained. When wiping in step S104 is completed, the maintenance unit 5 moves to the retreat position Pb, 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 wiping. This washes away any adhering matter (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.

In step S107, the cleaning liquid supply unit 8 executes the bubble mode to eject foamed cleaning liquid Lb from the cleaning liquid nozzle 85 onto the wiper 54. This foamed cleaning liquid Lb contains air bubbles, so 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.

When the ejection of the foam cleaning liquid Lb onto the wiper 54 is complete, the maintenance unit 5 is positioned at the retreated position Pb (step S108), and the maintenance in FIG. 9 ends. This allows, for example, the head unit 3 to be lowered from the wiping height h2 to the printing height h0, and a printing operation can be started in which ink is ejected from the head unit 3 onto the web W.

In this embodiment, the foamy cleaning liquid Lb (first cleaning liquid) is also 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 a strong cleaning power, and the amount of foamy cleaning liquid Lb required to remove ink can also be reduced.

The cleaning liquid supply unit 8 also selectively supplies the wiper 54 with either the foamy cleaning liquid Lb or a cleaning liquid Lo (second cleaning liquid) different from the foamy cleaning liquid Lb (steps S101 and S107). With this configuration, the wiper 54 can perform various processes other than removing ink with the foamy cleaning liquid Lb.

In particular, the cleaning liquid Lo does not contain air bubbles. As described above, such cleaning liquid Lo can be used to rinse the foamy cleaning liquid Lb from the wiper 54. In other words, since the foamy cleaning liquid Lb contains air bubbles, it does not flow immediately after being supplied to the wiper 54 and remains on the wiper 54. Therefore, the foamy cleaning liquid Lb can be rinsed away with the cleaning liquid Lo that does not contain air bubbles, thereby cleaning the wiper 54.

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 raw liquid ejection unit 81 corresponds to an example of the "raw 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.

The present invention is not limited to the above-described 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.

In the "bubble mode", when the raw liquid discharge unit 81 discharges the cleaning liquid Lo while the air discharge unit 82 discharges air, the cleaning liquid Lo discharged from the raw liquid discharge unit 81 and the air discharged from the air discharge unit 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 to generate a foamed cleaning liquid Lb (= cleaning liquid Lo + air A) containing fine bubbles. Then, this foamed cleaning liquid Lb is discharged from the opening 851 of the cleaning liquid nozzle 85. In the "rinse mode", when the raw liquid discharge unit 81 discharges the cleaning liquid Lo with the air discharge unit 82 stopping air discharge, the cleaning liquid Lo discharged from the raw liquid discharge unit 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, in the second example, the cleaning liquid supply unit 8 also discharges foamy cleaning liquid Lb containing air bubbles from the cleaning liquid nozzle 85 by executing the bubble mode, and discharges cleaning liquid Lo that does not contain air bubbles from the cleaning liquid nozzle 85 by executing the rinse mode.

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

Figure 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 pipe 861 and 862 is connected to the 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.

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

In the rinse mode, the solenoid valve 88 connects the stock solution discharge unit 81 to the pipe 862 and blocks the stock solution discharge unit 81 from the pipe 861. Therefore, the cleaning solution Lo discharged from the stock solution discharge unit 81 bypasses the bubble generating unit 87 and is discharged from the cleaning solution nozzle 85.

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 the system so that two types of foamy cleaning liquid Lb with different bubble states are discharged to the wiper 54. Figure 14 is a diagram showing, in table form, the operation of discharging two types of foamy cleaning liquid by the cleaning liquid supply unit in Figure 5.

As shown in FIG. 14, in the "first bubble mode", the raw liquid discharge unit 81 discharges the cleaning liquid Lo, and the air discharge unit 82 discharges air A at a speed V1 (flow rate), generating a foamed cleaning liquid Lb1 containing air bubbles. In the "second bubble mode", the raw liquid discharge unit 81 discharges the cleaning liquid Lo, and the air discharge unit 82 discharges air A at a speed V2 (flow rate), 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.

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.

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.

As shown in FIG. 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 with different bubble states, and discharging them onto the wiper 54. With this configuration, the foamed cleaning liquid Lb1 and foamed cleaning liquid Lb2 can be easily used by changing the speed at which the air A is mixed with the cleaning liquid Lo (original liquid).

Although the above describes a form in which cleaning liquid is ejected onto the wiper 54, the cleaning liquid nozzle 85 may also eject cleaning liquid onto members 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 eject cleaning liquid onto not only the wiper 54 but also the wiper lifting mechanism 55.

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 parts, 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 part of the wiper fixing bracket 55a. The cam 55c is disposed in the waste liquid container 513 and rotates in the Y direction by a motor (not shown). This causes the wiper 54, wiper fixing bracket 55a, and bolt 55b to be raised and lowered in the Z direction.

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

Here, the thickness of the layer of foamy cleaning liquid Lb attached to the wiper 54, wiper fixing bracket 55a, and 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 wiper fixing bracket 55a, and the symbol Rm indicates the X direction region of the wiper 54. Region Re is defined as both end regions Re, and region Rm between both end regions Re is defined as the central region Rm.

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

Specifically, the speed at which the wiper 54 and the wiper fixing bracket 55a move in the X direction relative to the cleaning liquid nozzle 85 during the period when foamed cleaning liquid Lb is ejected from the cleaning liquid nozzle 85 to the end regions Re is slower than the speed at which the wiper 54 and the wiper fixing bracket 55a move in the X direction relative to the cleaning liquid nozzle 85 during the period when foamed cleaning liquid Lb is ejected from the cleaning liquid nozzle 85 to the central region Rm, thereby forming the state shown in FIG. 15A. This state is suitable, for example, when there is significant ink adhesion in the end regions Re.

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 bracket 55a move in the X direction relative to the cleaning liquid nozzle 85 during the period when foamy cleaning liquid Lb is ejected 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 bracket 55a move in the X direction relative to the cleaning liquid nozzle 85 during the period when foamy cleaning liquid Lb is ejected 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 ink adhesion in the central region Rm.

In this way, when the foamed cleaning liquid Lb is supplied from the cleaning liquid nozzle 85 to the wiper 54 and the wiper fixing bracket 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 bracket 55a. In this configuration, an appropriate thickness of foamed cleaning liquid Lb can be applied to the wiper 54 and the wiper fixing bracket 55a to remove ink from the wiper 54 and the wiper fixing bracket 55a. Note that the movement of the wiper 54 and the wiper fixing bracket 55a relative to the cleaning liquid nozzle 85 can be performed by driving the cleaning liquid nozzle 85, not limited to driving the wiper 54 and the wiper fixing bracket 55a. In short, it is sufficient if the wiper 54 and the wiper fixing bracket 55a can be moved relative to the cleaning liquid nozzle 85.

The method of changing the thickness of the layer of foamy cleaning liquid Lb is not limited to the above. For example, the amount of cleaning liquid supplied by the cleaning liquid nozzle 85 to the end regions Re and the central region Rm can be varied to change the thickness of the layer of 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 bracket 55a may be constant. Alternatively, the moving speed of the cleaning liquid nozzle 85 during the period when it moves through the end regions Re may be slower than the moving speed during the period when it moves through the central region Rm.

Furthermore, the thickness of the layer of foamy 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.

For example, foamy cleaning liquid Lb2 is discharged from the cleaning nozzle 85 to the end regions Re. Since the foamy cleaning liquid Lb2 contains many large bubbles, it adheres to the end regions Re in a thick layer. At this time, it is desirable for the cleaning nozzle 85 to discharge the foamy cleaning liquid Lb2 while stopped relative to the wiper fixing bracket 55a.

On the other hand, foamy cleaning liquid Lb1 is discharged from the cleaning nozzle 85 to the central region Rm. The size of the air bubbles contained in the foamy cleaning liquid Lb1 is smaller than the size of the air 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 for the cleaning nozzle 85 to discharge the foamy cleaning liquid Lb1 while stopped relative to the wiper 54, but the foamy cleaning liquid Lb1 may also be discharged while moving.

It is also possible to apply cleaning liquid with a thin foam to the end regions Re, and cleaning liquid with a thick foam to the center region Rm. In this case, foamy cleaning liquid Lb1 is discharged from the cleaning nozzle 85 to the end regions Re, and foamy cleaning liquid Lb2 is discharged from the cleaning nozzle 85 to the center region Rm.

Movement of the wiper 54 relative to the head unit 3 for wiping is not limited to driving the wiper 54, but may be performed by driving the head unit 3. In short, it is sufficient if the wiper 54 can be moved relative to the head unit 3.

The contents of the maintenance performed in FIG. 9 may be changed as appropriate. For example, step S101 in which cleaning liquid Lo is ejected onto the wiper 54 is not essential. In other words, if the foamed cleaning liquid Lb ejected onto the wiper 54 in step S107 has good foam removal, step S101 is not necessary. In this case, the cleaning liquid supply unit 8 does not need to be able to eject cleaning liquid Lo onto the wiper 54, and only needs to be able to eject foamed cleaning liquid Lb.

The present invention is applicable to all technologies 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.

1... Printing device 31... Discharge head 310... Nozzle facing plane (ink discharge surface)
311...Nozzle 54...Wiper (wiping member)
61...Horizontal drive unit (drive unit)
8... cleaning liquid supply unit 81... raw liquid discharge unit (raw liquid supply unit)
82: Air discharge section (gas supply section)
A...Air (gas)
Lb: Foamy cleaning liquid (first cleaning liquid)
Lo: cleaning solution (second cleaning solution)

Claims (10)

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,
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 . 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. The printing device according to claim 2, wherein the second cleaning liquid does not contain air bubbles. The printing device according to claim 3, wherein the cleaning liquid supply unit has an original liquid supply unit that supplies cleaning liquid that does not contain air bubbles, and a gas supply unit that 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. 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. The printing device 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. The printing device according to claim 5 or 6, wherein the cleaning liquid supply unit has a stock liquid supply unit that supplies cleaning liquid that does not contain bubbles, and a gas supply unit that supplies gas, and selectively generates the first cleaning liquid and the second cleaning liquid having different bubble states by changing the speed at which the cleaning liquid supplied from the stock liquid supply unit is mixed with the gas supplied from the gas supply unit, and supplies the first cleaning liquid and the second cleaning liquid to the wiping member. 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. 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. 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 supply unit ;
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 .

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