Cleaning and printing equipment

Abstract

To provide a cleaning device capable of being miniaturized.SOLUTION: A cleaning device 3 comprises a sheet-like web 32 for wiping an ink jet head, and a spray head 50 for spraying a cleaning liquid on the web 32 by turning it into a mist state by high-frequency oscillations.SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] The present disclosure relates to a cleaning device and a printing device. [Background technology]

[0002] Conventionally, cleaning devices (wiping units) for cleaning inkjet heads of inkjet printing devices (recording devices) have been disclosed, as disclosed in Japanese Patent Application Laid-Open No. 2004-167488 (Patent Document 1) and Japanese Patent Application Laid-Open No. 2012-176545 (Patent Document 2). In such cleaning devices, a cleaning liquid is sprayed onto a web from a cleaning liquid spray head using high-pressure air (or gas) while the web is moving. The ink ejection surface of the inkjet head is wiped by the web onto which the cleaning liquid has been sprayed.

[0003] Japanese Patent Laid-Open Publication No. 6-7720 (Patent Document 3) discloses an ultrasonic atomization device that drives a composite consisting of a piezoelectric vibrator and a vibrating body that comes into contact with a liquid-retaining agent. In this ultrasonic atomization device, when the composite is driven, the liquid in the liquid-retaining agent is atomized through holes provided in the vibrating body. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2004-167488 [Patent Document 2] Japanese Patent Application Laid-Open No. 2012-176545 [Patent Document 3] Japanese Patent Application Publication No. 6-7720 Summary of the Invention [Problem to be solved by the invention]

[0005] When high-pressure air (or gas) is used to spray the cleaning liquid onto the web from a spray head, as in Patent Documents 1 and 2, it is difficult to make the cleaning device smaller.

[0006] The present disclosure has been made in consideration of the above-mentioned problems, and aims to provide a cleaning device that can be made compact, and a printing device that includes the cleaning device. [Means for solving the problem]

[0007] According to one aspect of the present disclosure, a cleaning device includes a sheet-like web that wipes an inkjet head, and a spray head that uses high-frequency vibration to spray a cleaning liquid onto the web in the form of a mist.

[0008] Preferably, the spray head has a plurality of through holes formed therein for spraying the cleaning liquid into a mist.

[0009] Preferably, the opening area of ​​each through hole is 1 μm 2 More than 10,000 μm 2 The following is the result.

[0010] Preferably, each opening is circular, and the diameter of each opening is 1 μm or more and 100 μm or less.

[0011] Preferably, the spray head has a 1 cm 2 At least 10 through holes and up to 10,000 through holes are formed per unit area.

[0012] Preferably, the spray head sprays the cleaning liquid from the plurality of through holes in a direction downward from the horizontal direction. The spray head is installed near a position where the inkjet head is wiped.

[0013] Preferably, the spray head includes a vibrator having a plurality of through holes formed therein. Preferably, the vibrator has a vibration plate having a plurality of through holes formed therein and a piezoelectric element for vibrating the vibration plate. The spray head further includes a porous body in contact with the vibration plate and impregnated with the cleaning liquid. The cleaning device further includes a drive circuit for high-frequency driving the piezoelectric element.

[0014] Preferably, the piezoelectric element is a hollow cylinder having a first end face and a second end face opposite the first end face. The second end face is closer to the porous body than the first end face. The diaphragm has a circular outer shape and is disposed so as to cover at least a portion of the second end face of the piezoelectric element.

[0015] Preferably, the central portion of the vibration plate is convex toward the inner circumferential surface of the piezoelectric element, and at least some of the plurality of through holes are formed in the central portion.

[0016] Preferably, the spray head has a plurality of vibrators, and the drive circuit controls the driving of the piezoelectric element of each vibrator individually.

[0017] Preferably, the cleaning device is built into the printing device, and the printing device has a plurality of inkjet heads arranged in a direction in which paper is transported to be printed, and the vibrators are arranged side by side in the transport direction.

[0018] Preferably, the porous body has a first portion and a second portion having a thickness in the direction of the through-hole that is thinner than the first portion, and the second portion is in contact with the diaphragm.

[0019] Preferably, the cleaning device further includes a tank for storing the cleaning liquid and supplying the cleaning liquid to the spray head. The level of the cleaning liquid in the tank is lower than the level of the plurality of through holes.

[0020] Preferably, the drive circuit drives the piezoelectric element by one of voltage control, frequency control, and pulse width modulation control.

[0021] Preferably, the cleaning device further includes a pair of electrodes in contact with the web impregnated with the cleaning liquid. The cleaning device detects the amount of cleaning liquid impregnated in the web based on the current flowing between the pair of electrodes. The drive circuit drives the piezoelectric element based on the detection result so that the amount of cleaning liquid impregnated in the web approaches a predetermined amount.

[0022] Preferably, the spray head sprays the cleaning liquid in the form of a mist onto the unused portion of the web, and the cleaning device moves the unused portion onto which the cleaning liquid has been sprayed to a position where it wipes the inkjet head.

[0023] According to another aspect of the present disclosure, a printing apparatus includes an inkjet head and a cleaning device for cleaning the inkjet head. The cleaning device includes a sheet-like web for wiping the inkjet head, and a spray head for spraying a cleaning liquid onto the web in the form of a mist using high-frequency vibrations. [Effects of the Invention]

[0024] According to the present disclosure, it is possible to reduce the size of the cleaning device. [Brief explanation of the drawings]

[0025] [Figure 1] FIG. 1 is a diagram illustrating the overall configuration of a printing apparatus. [Figure 2] 2 is a side view of the printing device of FIG. 1, viewed from the direction of arrow II. [Figure 3] 3 is a top view of the printing device of FIG. 1, viewed from the direction of arrow III. [Figure 4] FIG. 2 is a block diagram illustrating a hardware configuration of a cleaning device. [Figure 5] FIG. 2 is a schematic diagram illustrating a hardware configuration of a cleaning device. [Figure 6] FIG. 2 is a perspective view of a cleaning liquid supply device. [Figure 7] FIG. 2 is a perspective view of a spray head of the cleaning liquid supply device. [Figure 8] 7 is a bottom view of the cleaning liquid supply device of FIG. 6, viewed from the direction of arrow VIII. [Figure 9] 8 is a plan view of the vibrator of FIG. 7 as viewed in the direction of arrow IX. [Figure 10] FIG. 10 is a cross-sectional view taken along the line XX in FIG. 9. [Figure 11] It is an enlarged view of the main part of the diaphragm. [Figure 12] It is a sectional view taken along the line XII-XII of FIG. 11 as indicated by the arrow. [Figure 13] It is a circuit diagram of the head drive circuit of the cleaning device. [Figure 14] It is a schematic diagram schematically showing the operation of the head drive circuit. [Figure 15] It is a schematic diagram for explaining the hardware configuration of a modified example of the cleaning device. [Figure 16] It is a diagram for explaining the platen. [Figure 17] It is a diagram for explaining the head drive circuit of another cleaning device. [Figure 18] It is a diagram showing the relationship between the setting switch and the output of the vibrator. [Figure 19] It is a flowchart for explaining the control structure of the cleaning device.

Embodiments for Carrying Out the Invention

[0026] The printing device in the embodiment will be described below with reference to the drawings. In the embodiments described below, the same parts and corresponding parts may be given the same reference numerals, and redundant descriptions may not be repeated.

[0027] <A. Overall Configuration of the Printing Device> The printing device according to the present embodiment is an inkjet printing device (recording device). Typically, the printing device is a production printer used in fields such as commercial printing and in-house printing of enterprises.

[0028] FIG. 1 is a diagram for explaining the overall configuration of the printing device according to the present embodiment. FIG. 2 is a side view showing the printing device of FIG. 1 from the direction of arrow II. FIG. 3 is a top view showing the printing device of FIG. 1 from the direction of arrow III.

[0029] 1, the printing device 1 includes a paper transport device 2, a cleaning device 3, a head standby unit 4, a controller 9, an inkjet head station 10, and a head moving device 11. The printing device 1 has multiple head stations 10, which will be described in detail later.

[0030] The cleaning device 3 has a backup roller 31. The head standby section 4 has a cap 41 and a waste liquid tank 42. The head standby section 4 has a plurality of caps 41, the details of which will be described later.

[0031] The paper transport device 2 includes a transport belt 20, a drive roller 21, and a driven roller 22 (FIG. 2). The paper 900 is transported by the transport belt 20.

[0032] The head station 10 is fixed to a head moving device 11. By moving the head moving device 11, the head station 10 can move in the direction of arrow 990 (positive and negative directions of the X axis) and in the direction of arrow 991 (positive and negative directions of the Z axis).

[0033] A paper transport device 2 is disposed below the head station 10. When the head station 10 moves in the direction of the arrow 990, the cleaning device 3 and the head standby unit 4 are located below the head station 10.

[0034] 2, when the head moving device 11 is located directly above the paper transport device 2, the transport belt 20 rotates due to the rotation of the drive roller 21 and the driven roller 22 in the direction of arrow 992. As a result, the paper 900 in close contact with the surface of the transport belt 20 is transported in the direction of arrow 993. As the paper 900 passes through the head station 10, ink is ejected from the head station 10, and an image is formed on the paper 900.

[0035] The head station 10 is positioned on the conveyor belt 20 during a series of print jobs. When the print job is completed, the head station 10 moves, in response to a command from the controller 9 (FIG. 1), to a position where the cleaning device 3 is waiting, and further to a position where the cap 41 is waiting.

[0036] 3, the printing apparatus 1 has multiple head stations 10. More specifically, the head moving device 11 has multiple head stations 10 for each ink type or color. The head stations 10 are aligned in a row in the Y-axis direction.

[0037] Each head station 10 has a plurality of inkjet heads 101. More specifically, in this example, each head station 10 has inkjet heads 101 arranged in two rows so that the inkjet heads 101 can print across the width of the paper.

[0038] A nozzle plate (not shown) is provided on the bottom surface of the inkjet head 101. The nozzle plate has a large number of nozzles formed therein that eject ink in multiple rows. The inkjet head 101 is provided with piping (not shown) for supplying and recovering ink.

[0039] The inkjet head 101 can supply and circulate ink through the piping. Furthermore, the inkjet head 101 is provided with a device (not shown) that controls the pressure applied to the ink. This device allows the inkjet head 101 to form an ink meniscus at the nozzle outlet. During purging, the pressure is controlled to expel ink from the nozzle.

[0040] A cleaning device 3 and a cap 41 are installed at a position (position in the X-axis direction) corresponding to each head station 10. In this way, the printing apparatus 1 has cleaning devices 3 and caps 41 for each head station 10. In the printing apparatus 1, maintenance of each head station 10 is performed by the cleaning device 3 and cap 41 corresponding to the head station 10.

[0041] 1, after the head station 10 executes a series of print jobs, the head moving device 11 moves the head station 10 to a position directly above the cleaning device 3. The head moving device 11 then moves downward (in the negative direction of the Z axis). This causes a cleaning member (contact wiping member) called a web in the cleaning device 3 to come into contact with a nozzle plate (not shown) on the surface of the inkjet head 101.

[0042] More specifically, relative movement occurs between the web and the head station 10 due to at least one of the movement of the head moving device 11 in the X-axis direction (in this example, the positive direction of the X-axis) and the movement of the cleaning device 3 along the web. This causes the nozzle plate to be rubbed by the web. As a result, stains such as ink adhering to the surface of the nozzle plate are removed.

[0043] When the head station 10 is on standby without executing a job, the head moving device 11 moves the head station 10 to a position facing the cap 41. The cap 41 is shaped (container-like) to cover the head station 10. The cap 41 seals the nozzle plate. The reason for sealing it is to prevent bending (warping) and damage in the vicinity of the nozzles due to drying of ink near the nozzles.

[0044] There is a space between the nozzle plate covered by the cap 41 and the bottom surface of the cap. This space is filled with a storage liquid or the like so that the wet state is maintained. The storage liquid may have a composition that prevents the evaporation of the ink solvent. Also, a waste liquid tank 42 is installed under the cap 41 so that a purge (injecting ink) process can be performed when the nozzle plate is covered by the cap 41. A pipe (not shown) is provided on the bottom surface of the cap 41. Further, the printing apparatus 1 is also equipped with a mechanism for discharging the ink purged into the waste liquid tank 42.

[0045] Note that after the purge process is completed, the head moving device 11 can also move to the cleaning device 3 to clean the nozzle plate contaminated with the purged ink.

[0046] <B. Cleaning Device> (b1. Overall Configuration) FIG. 4 is a block diagram for explaining the hardware configuration of the cleaning device 3.

[0047] As shown in FIG. 4, the cleaning device 3 includes a web conveying device 30, a cleaning liquid supply device 5, and a head drive circuit 7.

[0048] The web conveying device 30 includes a backup roller 31, a drive roller 33, conveying rollers 34a and 34b, a web supply roller 35, a web winding-up roller 36, and a roller drive device 37. The roller drive device 37 has a motor 38a, a motor drive circuit 39a for driving the motor 38a, a motor 38b, and a motor drive circuit 39b for driving the motor 38b.

[0049] The cleaning liquid supply device 5 includes a spray head 50 and a tank 54. The spray head 50 includes a plurality of vibrators 51. In this example, the case where the spray head 50 includes three vibrators 51 is illustrated.

[0050] The head drive circuit 7 and the motor drive circuits 39a and 39b operate based on commands from the controller 9. The operation of each hardware block of the cleaning device 3 will be described later.

[0051] FIG. 5 is a schematic diagram for explaining the hardware configuration of the cleaning device 3. As shown in FIG. 5, the cleaning device 3 includes a web transport device 30 and a spray head 50. The web 32 is in a sheet form. At the start of use, the web 32 is placed in the cleaning device 3 in a roll form.

[0052] The web 32 is supplied from a web supply roller 35. The web 32 passes through a transport roller 34b, a backup roller 31, a transport roller 34a, and a drive roller 33 in this order, and is then wound up by a web wind-up roller 36.

[0053] The movement (transport) of the web 32 is performed by a driving roller 33. The driving roller 33 is a pair of rollers. A motor 38a (FIG. 4) is connected to one side of the driving roller 33.

[0054] The web supply roller 35 rotates as the web 32 is pulled by the drive roller 33. This causes the web 32 to be supplied to the wiping position P. A torque limiter (not shown) is connected to the rotation shaft of the web supply roller 35. In the cleaning device 3, the torque limiter generates a constant dynamic friction force, thereby stabilizing the tension of the web 32. The torque limiter also prevents the web 32 from continuing to rotate due to inertia when it is stopped.

[0055] A motor 38b (FIG. 4) is connected to the rotation shaft of the web winding roller 36. Furthermore, a torque limiter (not shown) is provided between the motor 38b and the rotation shaft of the web winding roller 36.

[0056] The rotation speed of the motor 38b that drives the web winding roller 36 is set so that the surface speed of the web 32 wound up by the web winding roller 36 is faster than the actual conveyance speed of the web 32 (the conveyance speed of the web 32 by the conveyance rollers 34a, 34b). By setting it in this way, the torque limiter functions to keep the conveyance speed of the web 32 and the surface speed of the web wound up by the web winding roller 36 constant, regardless of the accumulation amount (thickness) of the web 32 wound up by the web winding roller 36.

[0057] The drive source of the drive roller 33 (motor 38a in this example) and the drive source of the winding roller (motor 38b in this example) may be the same motor.

[0058] The web 32 may be a woven or knitted fabric such as cotton or synthetic fiber. The web 32 may also be a nonwoven fabric. When wiping the nozzle plate of the inkjet head 101 with the web 32, pre-wetting the web 32 with an appropriate liquid increases the ink absorption performance (initial absorption rate). Therefore, it is preferable to pre-wet the web 32 to wipe off unwanted ink on the nozzle plate. Also, even if ink adhering to the nozzle plate dries and hardens, a wet web 32 makes it easier to wipe off. For these reasons, the cleaning device 3 sprays a cleaning liquid onto the web 32 as it is transported, as described above.

[0059] The cleaning liquid supply device 5 is installed upstream of the backup roller 31 with respect to the transport path of the web 32. Since the inkjet head 101 (FIG. 3) comes into contact with the backup roller 31, the cleaning liquid supply device 5 (particularly the spray head 50) is installed near the backup roller 31 without interfering with the inkjet head 101.

[0060] The cleaning liquid supplying device 5 sprays the cleaning liquid onto the web 32. More specifically, the cleaning liquid supplying device 5 sprays the cleaning liquid onto an unused portion of the web 32.

[0061] More specifically, as described above, the cleaning liquid supply device 5 has the spray head 50. The spray head 50 is filled with a sheet-like (stepped) porous body 52 impregnated with the cleaning liquid. As will be described in detail later, the spray head 50 is formed with a plurality of through-holes 550 (FIG. 11) that turn the cleaning liquid into a mist.

[0062] The spray head 50 uses high-frequency vibration to turn the cleaning liquid impregnated in the porous body 52 into a mist, and sprays the mist onto an unused portion of the web 32. In this example, the spray head 50 sprays the cleaning liquid onto a region (portion) of the web 32 between the transport roller 34b and the backup roller 31. The spray head 50 sprays the cleaning liquid onto the upstream side of the backup roller 31 in the transport path of the web 32. The spray head 50 sprays the cleaning liquid onto the surface of the web 32 upstream of the wiping position P.

[0063] Specifically, the spray head 50 sprays the cleaning liquid in a direction downward from the horizontal. The spray head 50 is driven (operated) by the head drive circuit 7. This driving causes the spray head 50 to spray the cleaning liquid. The unused portion of the web 32 onto which the cleaning liquid has been sprayed is moved by the drive roller 33 to a wiping position P where it wipes the inkjet head 101.

[0064] If the supply (spraying) of cleaning liquid to the web 32 were stopped at the same time as the wiping operation was stopped, the cleaning liquid between the spray head 50 and the backup roller 31 would evaporate by the time of the next operation. Therefore, the amount of cleaning liquid impregnated into the web 32 during this period would decrease. On the other hand, if the supply of cleaning liquid to the web 32 had been stopped before the wiping operation was stopped, a region between the spray head 50 and the backup roller 31 would be left unimpregnated with cleaning liquid. Therefore, this region would no longer be usable for cleaning.

[0065] In this regard, as described above, the spray head 50 uses the sheet-like porous body 52, and therefore the housing itself is thin. This allows the spray head 50 to be brought closer to the backup roller 31. Therefore, after wiping the inkjet head 101 once with the web 32 and stopping the operation, when the next wiping operation starts, it is possible to reduce waste of the web 32 from the spray head 50 to the wiping position P of the backup roller 31 and waste of cleaning liquid.

[0066] The advantages of the cleaning device 3 will be explained using a comparative example. For example, in other configurations where cleaning liquid is dropped from a nozzle (hereinafter also referred to as the "first comparative example"), the only option is to wait for the cleaning liquid to wet the web and spread, which takes a very long time. Therefore, in such configurations, a sufficient distance must be secured between the cleaning liquid supply position and the backup roller.

[0067] In addition, in the case of a further configuration (hereinafter also referred to as "second comparative example") in which the cleaning liquid is sprayed from a spray nozzle using high-pressure air (or gas), a certain distance must be secured between the nozzle and the web, and since the cleaning liquid does not spread widely, multiple nozzles must be installed.

[0068] For this reason, in the configurations of these comparative examples, it is difficult to install the nozzle of the cleaning liquid supply device near the backup roller. On the other hand, in the cleaning device 3 of the present embodiment, as described above, the spray head 50 can be installed near the backup roller 31. Therefore, in the cleaning device 3, the above-mentioned waste can be reduced.

[0069] (b2. Example of the configuration of a cleaning liquid supply device) Next, a specific configuration of the cleaning liquid supply device 5 will be described. Fig. 6 is a perspective view of the cleaning liquid supply device 5. Fig. 7 is a perspective view of the spray head 50 of the cleaning liquid supply device 5. Fig. 8 is a bottom view of the cleaning liquid supply device 5 in Fig. 6, viewed from the direction of arrow VIII.

[0070] 6, the cleaning liquid supply device 5 includes a spray head 50 and a tank 54. As described above, the spray head 50 includes three vibrators 51 (vibrators 51a, 51b, 51c) and a porous body 52. ​​The vibrators 51 are arranged side by side in the conveyance direction (positive direction of the Y axis) of the paper 900. As will be described in detail later, each vibrator 51 vibrates at a high frequency.

[0071] The tank 54 has a connection part 541, a cleaning liquid supply port 542, and a porous body 55. The porous body 55 is filled in the tank 54. The tank 54 stores the cleaning liquid and supplies the cleaning liquid to the spray head 50. The porous body 55 of the tank 54 is impregnated with the cleaning liquid supplied from the cleaning liquid supply port 542. The porous body 52 of the spray head 50 is also impregnated with the cleaning liquid supplied from the tank 54.

[0072] The spray head 50 is connected to the tank 54 by inserting the spray head 50 into the connection portion 541 of the tank 54. Therefore, the spray head 50 is rotatable relative to the tank 54 around the shaft 58 as the center of rotation.

[0073] The XYZ coordinate system in the figure is a coordinate system based on the printing device 1 and the cleaning device 3. The xyz coordinate system is a coordinate system (local coordinate system) based on the spray head 50. The Y axis and the y axis are parallel. The XZ plane and the xz plane are parallel. The xy plane is parallel to the bottom surface 57 of the spray head 50.

[0074] 7, the spray head 50 further includes a porous body 53 that supplies the cleaning liquid from a tank 54 to the porous body 52. ​​The porous body 53 is connected to the porous body 52. ​​The porous body 53 and the porous body 52 may be formed integrally.

[0075] The sheet-like porous body 52 of the spray head 50 has a first portion 521 and a second portion 522 that is thinner than the first portion 521. The second portion 522 is in contact with each of the vibrators 51.

[0076] In this way, by making the second portion 522 on the back side of each vibrator 51 thin sheet-like, the thickness of the tip portion of the spray head 50 is reduced. On the other hand, in the first portion 521 away from the vibrator 51, the porous body 52 is made thicker, thereby increasing the amount of cleaning liquid that can be held. As a result, during continuous operation, the first portion 521 acts as a buffer, and cleaning liquid is sufficiently supplied to each vibrator 51.

[0077] 8, the porous body 53 is also connected to the porous body 55 of the tank 54. This allows the cleaning liquid in the tank 54 to be supplied to the porous body 52 via the porous body 53. As a result, the cleaning liquid in the tank 54 is supplied to each vibrator 51.

[0078] The liquid level of the cleaning liquid in the tank 54 is set lower than the vibrators 51 (more specifically, the multiple through holes described later) in order to prevent the cleaning liquid from leaking out when the vibrators 51 are not operating.

[0079] Furthermore, two wires 59 are connected to each vibrator 51. As will be described in detail later, when electricity is passed through the wires 59, each vibrator 51 vibrates.

[0080] Fig. 9 is a plan view of vibrator 51 of Fig. 7 as seen from the direction of arrow IX. Fig. 10 is a cross-sectional view taken along line XX of Fig. 9.

[0081] 9 and 10, vibrator 51 includes piezoelectric element 511 and vibration plate 512. Vibration plate 512 includes central portion 5122 and peripheral portion 5121 surrounding central portion 5122.

[0082] Piezoelectric element 511 has a hollow cylindrical shape. Piezoelectric element 511 has hollow circular end face 511a and end face 511b (FIG. 10) opposite end face 511a. End face 511b is closer to porous body 52 than end face 511a.

[0083] The diaphragm 512 is a thin circular metal plate. That is, the outer shape of the diaphragm 512 is circular. The diaphragm 512 is arranged so as to cover at least a part of the end surface 511b of the piezoelectric element 511. In this example, the diaphragm 512 covers the entire end surface 511b. More specifically, the diaphragm 512 is bonded to the piezoelectric element 511.

[0084] The vibration plate 512 has a first surface 512a and a second surface 512b opposite to the first surface 512a. The first surface 512a is bonded to an end surface 511b of the piezoelectric element 511. The second surface 512b is in contact with the porous body 52 containing the cleaning liquid. More specifically, the second surface 512b is in contact with a second portion 522 of the porous body 52.

[0085] More specifically, central portion 5122 of diaphragm 512 is convex in the positive direction of the z-axis relative to peripheral portion 5121. Central portion 5122 of diaphragm 512 is convex. More specifically, central portion 5122 of diaphragm 512 is convex in the direction of inner circumferential surface 511c of piezoelectric element 511.

[0086] The material of diaphragm 512 is typically a nickel alloy, an iron alloy, or an aluminum alloy. The thickness of diaphragm 512 is 50 μm or more and 500 μm or less. The outer diameter of diaphragm 512 is approximately the same as the outer diameter of piezoelectric element 511.

[0087] More specifically, piezoelectric element 511 has electrodes (not shown) on each of its top and bottom surfaces. In this example, end surfaces 511a and 511b serve as electrodes. Wiring 59 (see FIG. 8) is connected to these electrodes. When a high-frequency voltage is applied between the two electrodes, piezoelectric element 511 generates vibrations that expand and contract in the z-axis direction (positive and negative directions of the z-axis) and vibrations that expand and contract in the radial direction of the hollow circle.

[0088] Piezoelectric element 511 is typically made of ceramic except for the electrodes. Piezoelectric element 511 typically has a thickness (z-axis direction) of 1 to 5 mm and an outer diameter of 10 to 30 mm. The natural frequency of piezoelectric element 511 may be 30 kHz to 500 kHz when equipped with diaphragm 512.

[0089] 11 is an enlarged view of a main part of diaphragm 512. FIG. 12 is a cross-sectional view taken along line XII-XII in FIG.

[0090] 11, a plurality of through holes 550 are formed in at least the central portion 5122. The through holes 550 may be formed throughout the entire central portion 5122, or may be formed only in a part of the central portion 5122 (typically, a region near the center of the central portion). Furthermore, the through holes 550 may also be formed in a part of the peripheral portion 5121.

[0091] 12, each through hole 550 has an opening 560. More specifically, each through hole 550 has an opening 561 and an opening 562. The opening 561 is an opening on the web 32 side. The opening 562 is an opening on the porous body 52 side.

[0092] The through-hole 550 is a micro-hole. The area of ​​the openings 561 and 562 of the through-hole 550 is 1 μm 2 More than 10,000 μm 2 It is preferable that the diameter of the openings 561, 562 is 1 μm or more and 100 μm or less. It is preferable that the diameter of the openings 561, 562 is 1 μm or more and 100 μm or less. If the diameter of the openings 561, 562 is 0.1 μm to 100 μm, mist is generated.

[0093] Diaphragm 512 has a 1cm 2 The density of the through holes 550 is 500 / cm or more. 2 More than 5000 pieces / cm 2 It is preferable that:

[0094] By vibrating piezoelectric element 511 at high frequency, central portion 5122 of vibration plate 512 vibrates in the positive and negative directions of the z-axis. In this example, the natural frequency of vibrator 51 is approximately 100 kHz. When vibration plate 512 vibrates, the cleaning liquid on the back surface of vibration plate 512 (cleaning liquid in porous body 52) passes through each through-hole 550 and becomes atomized particles (mist), which are then sprayed into the air.

[0095] Specifically, since central portion 5122 of diaphragm 512 is convex, vibrations of diaphragm 512 in the vertical direction (positive and negative directions of the z-axis) are stabilized. This makes it possible to generate uniform mist. If the central portion were flat, there would be a distribution of vibration strength, with some areas vibrating strongly and others vibrating weakly, preventing the generation of uniform mist.

[0096] (b3. Controlling the amount of cleaning solution impregnated) If the amount of cleaning liquid impregnated into the web 32 is too small, it is difficult to remove ink that has adhered to the nozzle plate of the inkjet head 101 (FIG. 3). For this reason, a certain amount of impregnation is required. Furthermore, because the web 32 has a high ink absorption capacity, if the amount of cleaning liquid impregnated into the web 32 is too small, the web 32 will easily suck out ink from the nozzles of the nozzle plate. On the other hand, if the amount of cleaning liquid impregnated into the web 32 is too large, it will be difficult for the web 32 to absorb ink that has adhered to the nozzle plate after purging. Furthermore, if the amount of impregnation is too large, there is a risk that cleaning liquid will remain on the surface of the nozzle plate.

[0097] In this regard, the cleaning liquid supplying device 5 can freely adjust the amount of cleaning liquid impregnated into the web 32 based on the type of web 32 and the state of the nozzle plate of the inkjet head 101. In other words, the cleaning liquid supplying device 5 makes it very easy to adjust the amount of cleaning liquid impregnated into the web 32. The reason for this will be explained below.

[0098] For example, in the first comparative example, in which the cleaning liquid is dropped from a nozzle, the amount of impregnation is adjusted by the number of drops per unit time. However, if the amount of impregnation is low, the drops are intermittent. This results in a lack of uniformity in the amount of impregnation. In the second comparative example, in which the cleaning liquid is sprayed from a spray nozzle using high-pressure air (or gas), even if the air (or gas) pressure is set to achieve a desired amount of spray, the cleaning liquid does not become mist-like. Furthermore, in the case of a spray nozzle, the response between starting and stopping the spray is slow. Thus, in the second comparative example, it is difficult to adjust the amount of cleaning liquid supplied.

[0099] In contrast to these, the cleaning liquid supply device 5 according to this embodiment sprays atomized cleaning liquid (mist) from a planar vibrator 51. This allows the distance between the vibrator 51 and the web 32 to be shortened. Also, the responsiveness of the mist spray and its stop is higher than that of the configuration of the comparative example described above. This makes it very easy to adjust the amount of spray (atomization) in the cleaning liquid supply device 5.

[0100] Next, a method for adjusting the amount of cleaning liquid sprayed will be described. As described above, the spray head 50 is driven by the head drive circuit 7 (FIG. 4). Therefore, the configuration and operation of the head drive circuit 7 will be described.

[0101] As described above, diaphragm 512 having a plurality of through-holes 550, which are micropores, is vibrated by piezoelectric element 511. Vibrator 51, which is made up of piezoelectric element 511 and diaphragm 512, has a natural frequency. When vibrations of the same frequency as the natural frequency are applied to vibrator 51, vibrator 51 resonates. When vibrator 51 is vibrated at a frequency (resonant frequency) at which such resonance occurs, energy efficiency is high. Therefore, in this embodiment, vibrator 51 is resonated.

[0102] Fig. 13 is a circuit diagram of the head drive circuit 7 of the cleaning device 3. Note that Fig. 13 illustrates, for each of the vibrators 51a, 51b, and 51c, the main body 5111, which is the ceramic portion of the piezoelectric element 511, and the electrodes 5112, 5112 of the piezoelectric element 511, but does not illustrate the vibration plate 512.

[0103] 13, the head drive circuit 7 includes a step-up transformer 71, a switching element 72, a CR circuit 73, a logic element 74, and an oscillation circuit 75. The switching element 72 includes a gate 72g. The CR circuit 73 includes a resistor 73a and a capacitor 73b.

[0104] Oscillator circuit 75 is a circuit that outputs a square wave with the same frequency as the natural frequency of vibrator 51. CR circuit 73 cuts off high frequencies from the square wave oscillated from oscillator circuit 75. The square wave from which the high frequencies have been cut is input to gate 72g of switching element 72. This square wave causes switching element 72 to repeatedly turn on and off.

[0105] The switching element 72 drives the primary side of the step-up transformer 71. More specifically, when gate 72g is turned on, a direct current flows from the power supply DC to the primary side coil. When gate 72g is turned off, no direct current flows to the primary side coil. By controlling the current in the primary side coil in this way, a high-voltage pseudo-sine wave current with the same frequency as the natural frequency flows in the secondary side coil to which the vibrator 51 (51a, 51b, 51c) is connected. This current flows between the electrodes 5112, 5112 of the vibrator 51. As a result, the cleaning liquid is sprayed from the vibrator 51 in an atomized state (mist state).

[0106] More specifically, in the head drive circuit 7, the output from the oscillator circuit 75 is controlled (ON / OFF controlled) using a logic element 74. In this example, an AND circuit is used as the logic element 74. A square wave from the oscillator circuit 75 and a control signal from the controller 9 are input to the logic element 74. The output side of the logic element 74 is connected to the resistance element 73a of the CR circuit 73.

[0107] The atomization response by the vibrator 51 is high. By using a control signal from the controller 9 and the logic element 74, the amount of spray (amount of atomization) can be precisely controlled.

[0108] FIG. 14 is a schematic diagram showing the operation of the head drive circuit 7. As shown in FIG. 14, waveform (A) is the output of oscillator circuit 75. Waveform (B) is the signal input to logic element 74. Waveform (C) is the output signal output from logic element 74.

[0109] Switching element 72 drives vibrator 51 with waveform (C) of the output signal from logic element 74. As a result, atomization occurs only during the time that waveform (B) signal is high (times t1 to t2 and t3 to t4). Therefore, the spray amount (atomization amount) can be adjusted by the ratio (duty ratio) between high and low levels of waveform (B) signal.

[0110] In this way, the head drive circuit 7 controls the output of the vibrator 51 by pulse width. That is, pulse width modulation (PWM) control is performed in the head drive circuit 7. The frequency of the signal of waveform (B) is preferably between 0.2 Hz and a dozen Hz.

[0111] The above driving method is an example, and the amount of cleaning liquid sprayed (atomized) can be adjusted by changing the voltage applied to the vibrator 51 or by adjusting the frequency.

[0112] The head drive circuit 7 may individually control the driving of the piezoelectric elements 511 of each vibrator 51. For example, the oscillator circuit 75 may output a frequency signal that is individually set for each piezoelectric element 511. The controller 9 may also adjust the time that each piezoelectric element 511 remains high by sending a control signal (a signal with waveform (B)) that is individually set for each logic element 74 to the logic element 74.

[0113] <C. Cleaning Device (Parentheses)> (1) As shown in FIG. 5, the cleaning device 3 includes a sheet-like web 32 for wiping the inkjet head 101 and a spray head 50 for spraying the cleaning liquid in a mist form by high-frequency vibration onto the web 32.

[0114] According to such a configuration, there is no need for a pipe for the cleaning liquid and an air pipe (both are tubes at the 10 Mpa level) for spraying the cleaning liquid using high-pressure air (or gas). Also, a large pump for transporting the cleaning liquid at high pressure is not required. Furthermore, the distance between the spray head 50 and the web 32 can be made shorter than that in a configuration where the cleaning liquid is sprayed using high-pressure air (or gas). Therefore, the cleaning device 3 can be made smaller than a configuration where the cleaning liquid is sprayed using high-pressure air (or gas).

[0115] (2) As shown in FIG. 11, a plurality of through-holes 550 for making the cleaning liquid into a mist form are formed in the spray head 50. According to such a configuration, the cleaning liquid can be made into a mist form by the spray head 50.

[0116] (3) The area of the opening 560 (FIG. 12) of each through-hole 550 is preferably 1 μm 2 or more and 10000 μm 2 or less. According to such a configuration, when the cleaning liquid passes through each through-hole 550, the cleaning liquid becomes a mist form.

[0117] (4) Each opening 560 is preferably circular. The diameter of each opening 560 is preferably 1 μm or more and 100 μm or less. According to such a configuration, it is easy to form the through-holes 550.

[0118] (5) It is preferable that 10 or more and 10000 through-holes 550 are formed per 1 cm 2 on the spray head 50. According to such a configuration, a sufficient amount of mist can be sprayed.

[0119] (6) As shown in FIG. 5, the spray head 50 sprays the cleaning liquid from the multiple through-holes 550 in a downward direction relative to the horizontal. The spray head 50 is installed near the position where it wipes the inkjet head 101. This configuration allows the cleaning device 3 to be made smaller. In addition, the web 32 can be used efficiently.

[0120] (7) The spray head 50 includes a vibrator 51 formed with a plurality of through-holes 550. With this configuration, the vibration of the vibrator 51 makes it possible to spray the cleaning liquid from each of the through-holes 550 in the form of a mist.

[0121] (8) The vibrator 51 has a vibration plate 512 with a plurality of through holes 550 formed therein, and a piezoelectric element 511 that vibrates the vibration plate 512. As shown in FIGS. 5 to 8, the spray head 50 further includes a porous body 52 that is in contact with the vibration plate 512 and is impregnated with a cleaning liquid. As shown in FIGS. 4 and 13, the cleaning device 3 further includes a head drive circuit 7 that drives the piezoelectric element 511 at high frequency. With this configuration, it is possible to spray the cleaning liquid contained in the porous body 52 by driving the piezoelectric element 511.

[0122] (9) Piezoelectric element 511 has a hollow cylindrical shape. As shown in FIG. 10 , piezoelectric element 511 has hollow circular end face 511a and end face 511b opposite end face 511a. End face 511b is closer to porous body 52 than end face 511a. Diaphragm 512 has a circular outer shape. Diaphragm 512 is disposed so as to cover at least a portion of end face 511b of piezoelectric element 511. With this configuration, the driving force of piezoelectric element 511 can be efficiently transmitted to diaphragm 512.

[0123] (10) As shown in Fig. 10, central portion 5122 of vibration plate 512 is convex toward the inner circumferential surface of piezoelectric element 511. As shown in Fig. 11, at least some of multiple through holes 550 are formed in central portion 5122. This configuration stabilizes the vibration of vibration plate 512. This makes it possible to generate uniform mist.

[0124] (11) As shown in Figures 4, 6 to 8, and 13, the spray head 50 has multiple vibrators 51 (51a, 51b, 51c). As shown in Figure 13, the head drive circuit 7 individually controls the drive of the piezoelectric element 511 of each vibrator 51. This configuration enables more accurate spray control.

[0125] (12) As shown in FIG. 3, the cleaning device 3 is built into the printing device 1. In the printing device 1, multiple inkjet heads 101 (FIG. 3) are arranged in the transport direction (the direction of arrow 993 in FIG. 2) of the printing paper 900 (FIG. 2). The vibrators 51 are arranged side by side in the transport direction. With this configuration, it is possible to spray mist of cleaning liquid individually onto each area of ​​the web 32 used to wipe each inkjet head 101.

[0126] (13) As shown in FIG. 7, the porous body 52 has a first portion 521 and a second portion 522 that is thinner than the first portion 521 in the penetration direction of the through-hole 550 (see FIG. 12). As shown in FIGS. 7 and 10, the second portion 522 is in contact with the vibration plate 512. With this configuration, the cleaning liquid can be stored in the first portion 521. That is, the first portion 521 can function as a buffer portion for the second portion 522. Furthermore, because the second portion 522 is thinner than the first portion 521, the tip of the spray head 50 can be made thinner.

[0127] As shown in FIGS. 6 and 8, the cleaning device 3 further includes a tank 54 that stores the cleaning liquid and supplies the cleaning liquid to the spray head 50. The position of the liquid level of the cleaning liquid in the tank 54 is lower than the positions of the plurality of through holes 550. With such a configuration, leakage of the cleaning liquid from the plurality of through holes 550 can be prevented.

[0128] (15) The head drive circuit 7 drives the piezoelectric element 511 by any one of voltage control, frequency control, and pulse width modulation control. With such a configuration, the spraying amount of the cleaning liquid can be adjusted.

[0129] (16) The spray head 50 sprays the cleaning liquid in a mist form onto the unused portion of the web 32. The cleaning device 3 moves the unused portion onto which the cleaning liquid has been sprayed to the wiping position P (FIG. 5) for wiping the inkjet head 101.

[0130] (17) According to the cleaning device 3, it is possible to spread the cleaning liquid uniformly over the web 32. In particular, according to the cleaning device 3, the cleaning liquid can be spread to the ends over the width direction of the web 32. According to the cleaning device 3, the degree of freedom in selecting the web 32 increases.

[0131] <D. Modified Example> A configuration for controlling the impregnation amount of the cleaning liquid on the web 32 to be the specified (set) impregnation amount will be described.

[0132] FIG. 15 is a schematic diagram for explaining the hardware configuration of a modified example of the cleaning device 3.

[0133] As shown in FIG. 15, the cleaning device 3A is different from the cleaning device 3 in that it includes a platen 6 that functions as a sensor. The platen 6 is installed upstream of the backup roller 31 and downstream of the spray head 50.

[0134] Fig. 16 is a diagram illustrating the platen 6. As shown in Fig. 16, the platen 6 includes three electrode pairs 61. Each electrode pair 61 includes an electrode 61a and an electrode 61b spaced a predetermined distance from the electrode 61a.

[0135] Three electrode pairs 61 are arranged so as to be in contact with the surface of the web 32. Each electrode pair 61 is arranged at a position corresponding to a different transducer 51.

[0136] A constant tension is applied to the web 32, so that the web 32 is pressed against the platen 6 with a constant pressure. When a voltage is applied to the three electrode pairs 61, a current corresponding to the amount of cleaning liquid impregnated in the web 32 flows through each electrode pair 61. The cleaning device 3A detects the current and controls the output of each vibrator 51. This makes it possible to arbitrarily adjust the amount of cleaning liquid impregnated into the web 32.

[0137] FIG. 17 is a diagram for explaining the head drive circuit of the cleaning device 3A. 17, the head drive circuit 7A includes a step-up transformer 71, a switching element 72, a CR circuit 73, a logic element 74, a peripheral controller 76, an operational amplifier 77, a detection resistor 78, and an analog switch 79. The peripheral controller 76 has two setting switches 761 and 762. The head drive circuit 7A does not include an oscillator circuit 75.

[0138] The peripheral controller 76 executes a software program to generate signals that drive the three vibrators 51. Specifically, the peripheral controller 76 generates a signal identical to the waveform (C) shown in FIG. 14 (i.e., a signal that is the logical sum of the signal of waveform (A) in FIG. 14 and the signal of waveform (B) in FIG. 14). In doing so, the peripheral controller 76 determines the on / off ratio (duty ratio), which determines the amount of spray (amount of atomization), based on the current flowing through the electrode pair 61 of the platen 6.

[0139] Next, the detection of current will be described below. The analog switch 79 is turned on and off in response to a command from the peripheral controller 76. When the analog switch 79 is turned on, a voltage is applied between the electrode 61a and the electrode 61b.

[0140] If a configuration is adopted in which a voltage is constantly applied between electrodes 61a and 61b, the current flowing through the cleaning liquid will change (decrease). Therefore, highly accurate detection will not be possible. By using analog switch 79 as described above, it is possible to apply voltage only when necessary. Therefore, by adopting a configuration in which analog switch 79 is provided, more accurate detection will be possible than with a configuration in which a voltage is constantly applied between electrodes 61a and 61b.

[0141] Specifically, when a voltage is applied between electrodes 61a and 61b, a current corresponding to the amount of cleaning liquid in the web 32 flows between electrodes 61a and 61b. The peripheral controller 76 detects the amount of cleaning liquid impregnated into the web 32 based on the current flowing between electrodes 61a and 61b. Specifically, the current flowing between electrodes 61a and 61b is detected as a voltage signal by a detection resistor 78 and a high-input resistance operational amplifier 77. The detected voltage signal is input from the operational amplifier 77 to the peripheral controller 76.

[0142] Based on the detected amount of impregnated cleaning liquid (more specifically, the detected voltage signal), the peripheral controller 76 determines the on / off ratio of the vibrator 51. The process of determining this ratio is performed in the peripheral controller 76 using software (program).

[0143] This will be explained in more detail as follows: As described above, the peripheral controller 76 has two setting switches 761 and 762. The setting switches 761 and 762 are used to set the spray amount of each of the three vibrators 51.

[0144] FIG. 18 is a diagram showing the relationship between the setting switches 761 and 762 and the output of the vibrator 51. As shown in FIG.

[0145] As shown in Figure 18, two setting switches 761, 762 can be used to set four output patterns using a 2-bit signal. When both setting switches 761, 762 are on, pattern #0 is set and the outputs of the three vibrators 51 are low. This reduces the amount of spray from the three vibrators 51. When setting switch 761 is on and setting switch 762 is off, pattern #1 is set and the outputs of the three vibrators 51 are high. This increases the amount of spray from the three vibrators 51.

[0146] When setting switch 761 is off and setting switch 762 is on, pattern #2 is established, and only the output of vibrator 51c is high. The outputs of the remaining two vibrators 51a and 51b are low. When both setting switches 761 and 762 are on, pattern #3 is established, and only the output of vibrator 51a is high. The outputs of the remaining two vibrators 51b and 51c are low. In patterns #2 and #3, the amount of mist sprayed from the vibrator 51 at the end of the three vibrators is greater.

[0147] When the output of the vibrator 51 is low, the spray amount is 2 g / m 2 ~3g / m 2 In this case, the web 32 is still in a state where it can absorb enough ink. When the output of the vibrator 51 is high, the spray amount is 8 g / m 2 ~9g / m 2 In this case, the web 32 is sufficiently impregnated with the cleaning liquid.

[0148] The setting switches 761 and 762 can be directly operated by the user. The setting switches 761 and 762 are also operated by signals from a higher-level sequencer (not shown) that controls the printing device 1. After purging or after completing a print job, the setting switches 761 and 762 can be switched as desired by the controller 9, which includes the higher-level sequencer.

[0149] An operation start signal from the controller 9 is also input to the peripheral controller 76. That is, a command from the controller 9 starts a series of wiping operations.

[0150] 19 is a flow chart for explaining the control structure of the cleaning device 3 A. The sequence shown in FIG.

[0151] 19, in step S1, the peripheral controller 76 receives an input of an operation start signal from the upper controller 9. In step S2, the peripheral controller 76 checks the on / off states of the setting switches 761 and 762.

[0152] In step S3, the peripheral controller 76 drives the vibrator 51 with default settings. In step S4, the roller drive device 37 (FIG. 4) drives the drive roller 33. In step S5, the peripheral controller 76 checks the voltage between the electrode 61a and the electrode 61b.

[0153] In step S6, the peripheral controller 76 controls the driving of the vibrator 51 based on the voltage between the electrode 61a and the electrode 61b. In step S7, the peripheral controller 76 determines whether the roller drive device 37 has transported the web 32 by a predetermined length.

[0154] If it is determined that the web 32 has been transported a predetermined distance (YES in step S7), then in step S8, the peripheral controller 76 stops driving the vibrator 51. If it is determined that the web 32 has not been transported a predetermined distance (NO in step S7), the peripheral controller 76 returns the process to step S5. After step S8, in step S9, the roller driving device 37 stops driving the driving roller 33.

[0155] The embodiments disclosed herein should be considered to be illustrative in all respects and not restrictive. The scope of the present invention is defined by the claims, not by the above description, and is intended to include all modifications within the meaning and scope of the claims. [Explanation of symbols]

[0156] 1 printing device, 2 paper transport device, 3, 3A cleaning device, 4 head standby section, 5 cleaning liquid supply device, 6 platen, 7, 7A head drive circuit, 9 controller, 10 head station, 11 head moving device, 20 transport belt, 21, 33 drive roller, 22 driven roller, 30 web transport device, 31 backup roller, 32 web, 34a, 34b transport roller, 35 web supply roller, 36 web winding roller, 37 roller drive device, 38a, 38b motor, 39a, 39b motor drive circuit, 41 cap, 42 waste liquid tank, 50 spray head, 51, 51a, 51b, 51c vibrator, 52, 53, 55 porous body, 54 tank, 57 bottom, 58, Y, y axis, 59 wiring, 61 Electrode pair, 61a, 61b, 5112 Electrode, 71 Step-up transformer, 72 Switching element, 72g Gate, 73 Circuit, 73a Resistor element, 73b Capacitor, 74 Logic element, 75 Oscillator circuit, 76 Peripheral controller, 77 Operational amplifier, 78 Detection resistor, 79 Analog switch, 101 Inkjet head, 560, 561, 562 Opening, 550 Through hole, 511 Piezoelectric element, 511a, 511b End face, 511c Inner surface, 512 Vibration plate, 512a First surface, 512b Second surface, 521 First part, 522 Second part, 541 Connection part, 542 Cleaning liquid supply port, 761, 762 Setting switch, 900 Paper, 5111 Main body part, 5121 Peripheral part, 5122 Central part, P Wiping position.

Claims

1. A cleaning device, a sheet-like web for wiping the inkjet head; a spray head that uses high-frequency vibration to spray the cleaning liquid onto the web in mist form, The spray head includes a plurality of vibrators; Each of the vibrators has a vibration plate formed with a plurality of through holes for turning the cleaning liquid into mist, and a piezoelectric element for vibrating the vibration plate, the spray head further includes a porous body in contact with each of the vibration plates and impregnated with the cleaning liquid; the cleaning device further includes a drive circuit that drives the piezoelectric element of each of the vibrators at a high frequency; The driving circuit individually controls driving of the piezoelectric element of each of the vibrators.

2. the cleaning device is built into a printing device, and in the printing device, a plurality of the inkjet heads are arranged in a conveying direction of a printing paper; The cleaning device according to claim 1 , wherein the vibrators are arranged side by side in the transport direction.

3. A cleaning device, a sheet-like web for wiping the inkjet head; a spray head that uses high-frequency vibration to spray the cleaning liquid onto the web in mist form, The spray head includes a vibrator, the vibrator has a vibration plate formed with a plurality of through holes for turning the cleaning liquid into mist, and a piezoelectric element for vibrating the vibration plate; the spray head further includes a porous body in contact with the vibration plate and impregnated with the cleaning liquid; the cleaning device further includes a drive circuit that drives the piezoelectric element at a high frequency; the porous body has a first portion and a second portion having a thickness in a penetration direction of the through holes that is thinner than the first portion, The cleaning device, wherein the second portion is in contact with the vibration plate.

4. a tank for storing the cleaning liquid and supplying the cleaning liquid to the spray head; The cleaning device according to claim 3 , wherein the level of the cleaning liquid in the tank is lower than the level of the plurality of through holes.

5. The opening area of ​​each of the through holes is 1 μm ２ More than 10,000 μm ２ 5. The cleaning device according to claim 1, wherein:

6. The cleaning device of claim 5 , wherein each of the openings is circular.

7. The spray head has a 1 cm ２ The cleaning device according to claim 1 , wherein 10 to 10,000 through holes are formed per unit area.

8. The spray head is The cleaning liquid is sprayed from the plurality of through holes in a direction downward from the horizontal; The cleaning device according to claim 1 , wherein the cleaning device is installed near a position where the inkjet head is wiped.

9. the piezoelectric element is a hollow cylinder having a first end face of the hollow cylinder and a second end face opposite to the first end face; the second end surface is closer to the porous body than the first end surface; The cleaning device according to claim 1 , wherein the vibration plate has a circular outer shape and is disposed so as to cover at least a portion of the second end surface of the piezoelectric element.

10. The piezoelectric element further includes an inner circumferential surface, The center of the diaphragm is When viewed from the first end face side to the second end face side, the second end face side is located inside the inner circumferential surface, a convex shape from the second end face side toward the first end face side, The cleaning device according to claim 9 , wherein at least some of the plurality of through holes are formed in the central portion.

11. 11. The cleaning device according to claim 1, wherein the drive circuit drives the piezoelectric element by one of voltage control, frequency control, and pulse width modulation control.

12. The cleaning device a pair of electrodes in contact with the web impregnated with the cleaning liquid; detecting the amount of the cleaning liquid impregnated in the web based on the current flowing between the electrode pair; 12. The cleaning device according to claim 11, wherein the drive circuit drives the piezoelectric element based on the result of the detection so that the amount of the cleaning liquid impregnated into the web approaches a predetermined amount.

13. the spray head sprays the cleaning liquid in mist form onto the unused portion of the web; The cleaning device according to claim 1 , wherein the cleaning device moves the unused portion onto which the cleaning liquid has been sprayed to a position where the unused portion wipes the inkjet head.

14. The cleaning device according to any one of claims 1 to 13; a printing device comprising the inkjet head.

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