JP2023154263A - Cleaning device, image formation apparatus and control method - Google Patents

Abstract

To reduce abrasion around a nozzle in the time of cleaning of an ink jet head in comparison to a conventional technique.SOLUTION: A cleaning device 30 for cleaning a nozzle surface 13a on which a plurality of nozzles 22 is arrayed in a prescribed array direction in an ink jet head 13 includes cleaning means which continuously feeds a clean wiping member 31 toward a contact position with the nozzle surface 13a and cleans the nozzle surface 13a with the wiping member 31, and is configured to relatively move the cleaning means in the array direction of the plurality of nozzles 22 and relatively swing the cleaning means with respect to the ink jet head 13, so as to incline a wiping trace 29 formed on the wiping member 31 with respect to the array direction of the plurality of nozzles 22.SELECTED DRAWING: Figure 5

Description

The present invention relates to a cleaning device, an image forming device, and a control method, and particularly to a technique for cleaning a nozzle surface of an inkjet head.

An inkjet type image forming apparatus includes an inkjet head having a nozzle surface in which a plurality of nozzles for ejecting ink droplets are arranged in a predetermined arrangement direction. When an inkjet head ejects ink droplets from each of a plurality of nozzles, the ink adheres to the nozzle surface around the nozzle due to satellites or the like. Therefore, conventional image forming apparatuses include a cleaning device that cleans the nozzle surface of the inkjet head.

For example, a wiper member made of an elastic member that wipes the nozzle surface is provided, and by moving the wiper member in the extending direction of the nozzle surface while the wiper member is in contact with the nozzle surface, the wiper member wipes ink attached to the nozzle surface. There is a known cleaning device that wipes with water (for example, Patent Document 1).

Further, a cleaning device is also known in which a web-shaped wiping member containing a cleaning liquid is sent to a contact position with a nozzle surface, and the wiping member wipes the nozzle surface at the contact position (for example, Patent Document 2). This cleaning device wipes the entire nozzle surface by pressing a web-like wiping member against the nozzle surface with a roller and moving the contact position of the wiping member with the roller along the nozzle surface.

JP2009-226610A JP 2021-70289 Publication

However, the cleaning device described in Patent Document 1 moves the wiper member in the extending direction of the nozzle surface while being in contact with the nozzle surface, so that the ink scraped by the wiper member covers the nozzle surface together with the wiper member. Moving. Therefore, the ink moving together with the wiper member rubs against the nozzle surface, causing wear around the nozzle. In particular, the viscosity of the ink that adheres to the nozzle surface increases due to drying, and the ink adheres to the nozzle surface. Therefore, if the wiper member is moved while the ink is pressed against the nozzle surface by the wiper member, the nozzle surface will be severely worn out. do. Wear around the nozzle affects the landing position of ink droplets ejected from the nozzle, which causes image quality deterioration.

Further, the cleaning device described in Patent Document 2 sequentially and continuously sends out a clean wiping member toward the contact position with the nozzle surface by the roller, and winds up the wiping member that has passed the contact position with the nozzle surface. It is configured to collect ink wiped from the nozzle surface by moving the nozzle. However, the ink transferred to the wiping member does not immediately move in the winding direction of the wiping member, and may enter and remain at the contact position between the wiping member and the nozzle surface formed by the roller for a while. The ink that has entered the contact position between the wiping member and the nozzle surface scrapes the nozzle surface as the contact position moves along the nozzle surface. Therefore, although the cleaning device of Patent Document 2 has a lower degree of wear than the cleaning device of Patent Document 1, it still has the problem of causing wear around the nozzle.

SUMMARY OF THE INVENTION The present invention has been made in order to solve the above-mentioned conventional problems, and it is an object of the present invention to provide a cleaning device, an image forming device, and a control method that can reduce wear around a nozzle more than ever before. With the goal.

To achieve the above object, the invention according to claim 1 provides a cleaning device for cleaning a nozzle surface in which a plurality of nozzles are arranged in a predetermined arrangement direction in an inkjet head, the cleaning device being directed toward a contact position with the nozzle surface. cleaning means for continuously sending out a clean wiping member to clean the nozzle surface with the wiping member, moving the cleaning means relatively along the arrangement direction, and moving the cleaning means to the inkjet head. This configuration is characterized in that the wiping marks formed on the wiping member are tilted with respect to the arrangement direction by swinging the wiping member relative to the wiping member.

The invention according to claim 2 is the cleaning device according to claim 1, further comprising a swinging means for swinging the cleaning means relative to the inkjet head.

The invention according to claim 3 is the cleaning device according to claim 2, wherein the nozzle surface is provided with a plurality of nozzle rows arranged in a direction perpendicular to the arrangement direction, and the swinging means is arranged in a direction perpendicular to the arrangement direction. This structure is characterized in that the swing width when the inkjet head is caused to swing relative to the inkjet head is smaller than the arrangement interval of the plurality of nozzle rows.

The invention according to claim 4 is the cleaning device according to claim 3, wherein the swinging means swings the cleaning means relative to the inkjet head by the swinging width during the cleaning operation by the cleaning means. This is a configuration characterized by repeating the movement motion.

The invention according to claim 5 is the cleaning device according to claim 2, wherein the nozzle surface is provided with a plurality of nozzle rows arranged in a direction perpendicular to the arrangement direction, and the swinging means is configured to move the wiping member The structure is characterized in that the relative swing direction of the cleaning means with respect to the inkjet head is reversed before the wiping marks formed on the cleaning device reach adjacent nozzle rows among the plurality of nozzle rows. be.

According to a sixth aspect of the present invention, in the cleaning device according to the second aspect, a relative swinging speed of the swinging means is faster than a conveyance speed of the wiping members in the arrangement direction. It is.

The invention according to claim 7 is the cleaning device according to claim 2, further comprising pressing means for pressing the wiping member against the nozzle surface at the contact position, and the pressing means is configured such that the direction of rocking by the rocking means is This configuration is characterized in that when the wiping member is reversed, the pressing force of the wiping member against the nozzle surface is reduced.

The invention according to claim 8 is the cleaning device according to claim 2, wherein the swinging means swings the cleaning means.

The invention according to claim 9 is the cleaning device according to claim 8, wherein the swinging means linearly swings the cleaning means in a direction perpendicular to a sending direction of the wiping member. It is.

The invention according to claim 10 is the cleaning device according to claim 8, wherein the swinging means swings the cleaning means around a center by rotating the cleaning means within a predetermined angle range. It is configured to do this.

The invention according to claim 11 is the cleaning device according to claim 2, wherein the swinging means swings the inkjet head.

The invention according to claim 12 is the cleaning device according to claim 1, wherein the wiping member is constituted by a web.

The invention according to claim 13 is the cleaning device according to claim 1, wherein the wiping member is constituted by a roller.

The invention according to claim 14 is an image forming apparatus, which is characterized in that it includes the cleaning device according to any one of claims 1 to 13.

The invention according to claim 15 is a method of controlling a cleaning device for cleaning a nozzle surface in which a plurality of nozzles are arranged in a predetermined arrangement direction in an inkjet head, the cleaning device being at a contact position with the nozzle surface. The cleaning means is provided with a cleaning means for continuously sending out a clean wiping member toward the nozzle surface and cleaning the nozzle surface with the wiping member, and moving the cleaning means relatively along the arrangement direction and moving the cleaning means toward the nozzle surface. A control method characterized in that cleaning is performed by the cleaning means while tilting the wiping marks formed on the wiping member with respect to the arrangement direction by swinging the wiping member relative to the inkjet head.

According to the present invention, it is possible to reduce wear around a nozzle more than before, and it is possible to suppress deterioration of image quality.

1 is a diagram illustrating a schematic configuration of an image forming apparatus. FIG. 3 is a diagram showing an example of the configuration of a nozzle surface of an inkjet head. FIG. 3 is a diagram showing the internal configuration of an image forming section. FIG. 3 is an enlarged sectional view showing the internal structure of the cleaning device. FIG. 3 is a perspective view of the cleaning device. It is a figure explaining the wiping operation of the nozzle surface by a cleaning device. It is a figure explaining the wiping operation of the nozzle surface by a cleaning device. FIG. 6 is a diagram showing an example of wiping marks when the cleaning device is not oscillated. FIG. 6 is a diagram showing a first example of wiping marks when the cleaning device is oscillated. FIG. 7 is a diagram showing a second example of wiping marks when the cleaning device is oscillated. FIG. 7 is a diagram showing a third example of wiping marks when the cleaning device is oscillated. It is a flowchart which shows an example of the processing procedure when reversing the rocking direction of a cleaning device. It is a figure showing another example of composition of a rocking mechanism. It is a figure showing still another example of composition of a rocking mechanism. It is a figure which shows the other example of a structure of a wiping member. It is a figure which shows the evaluation result of a specific example.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings. In the embodiments described below, common elements are given the same reference numerals, and redundant explanations thereof will be omitted.

(Schematic configuration of image forming apparatus)
FIG. 1 is a diagram showing a schematic configuration of an image forming apparatus 1 according to an embodiment of the present invention. The image forming apparatus 1 is an inkjet type image forming apparatus, and includes a medium supply section 2, an image forming section 3, and a medium discharge section 4. The medium supply section 2 supplies the recording medium P to the image forming section 3. The image forming section 3 forms an image on the recording medium P conveyed from the medium supply section 2 . The medium discharge section 4 holds the recording medium P discharged from the image forming section 3. Further, the image forming apparatus 1 includes a control section 9 in the image forming section 3. The control unit 9 controls the operations of the medium supply unit 2, the image forming unit 3, and the medium discharge unit 4, and executes image formation on the recording medium P.

The recording medium P is in the form of a sheet, and in addition to paper such as plain paper or coated paper, it can also be made of various materials capable of fixing ink that has landed on the main surface of the sheet, such as cloth or sheet-like resin. A medium can be used.

In such an image forming apparatus 1, the recording medium P is conveyed to the medium supply section 2, the image forming section 3, and the medium discharge section 4 in this order. Here, the XYZ three-dimensional coordinate system shown in FIG. This is a coordinate system in which the horizontal direction perpendicular to the direction is the Y direction, and the vertical direction is the Z direction, and is a common coordinate system with the coordinate systems shown in other figures.

The medium supply section 2 includes a tray 5 on which the recording medium P is loaded, and a medium conveyance section 6 that conveys the recording medium P on the tray 5 to the image forming section 3. Based on the command from the control unit 9, the medium supply unit 2 takes out the topmost recording medium P from among the recording media P placed on the tray 5, and uses the medium transport unit 6 to perform recording on the recording medium P. The medium P is conveyed to the image forming section 3.

The image forming section 3 includes a transport drum 10 , a delivery unit 11 , a heating section 12 , a plurality of inkjet heads 13 , a fixing section 14 , and a delivery section 15 . The transport drum 10 has a cylindrical shape, and its outer peripheral side surface is configured as a suction surface that suctions and holds the recording medium P. The delivery unit 11 , the heating section 12 , the plurality of inkjet heads 13 , the fixing section 14 , and the delivery section 15 are arranged around the transport drum 10 .

The conveyance drum 10 rotates in one direction (in the illustrated example, counterclockwise) around the rotating shaft 10a, with the recording medium P attracted and held on the outer circumferential side surface. Thereby, the conveying drum 10 can sequentially convey the recording medium P held by suction on the outer peripheral side surface to positions facing each of the heating section 12, the plurality of inkjet heads 13, and the fixing section 14.

The delivery unit 11 receives the recording medium P conveyed by the medium conveyance section 6 of the medium supply section 2, and transfers the recording medium P to the conveyance drum 10. For example, the delivery unit 11 holds and picks up one end of the recording medium P conveyed from the medium conveyance section 6, and conveys it along the outer peripheral side of the conveyance drum 10, so that the conveyance drum 10 holds the recording medium P by suction. I will pass it on as I can.

The heating unit 12 is provided on the downstream side of the delivery unit 11, and heats the recording medium P so that the surface of the recording medium P that is attracted and held on the outer peripheral side of the conveyance drum 10 and conveyed has a temperature within a predetermined temperature range. Heat. For example, the heating unit 12 includes a heater such as an infrared heater, and heats the recording medium P by driving the heater based on a command from the control unit 9.

The plurality of inkjet heads 13 are provided downstream of the heating section 12 . In this embodiment, four inkjet heads 13 corresponding to four color inks, for example, yellow (Y), magenta (M), cyan (C), and black (K), are located on the upstream side in the rotational direction of the transport drum 10. They are arranged at predetermined intervals in order from top to bottom. Each inkjet head 13 is provided at a position where a nozzle surface 13a on which a plurality of nozzles are arranged is spaced a predetermined distance from the outer peripheral side surface of the conveyance drum 10. Each inkjet head 13 prints an image on the recording medium P by ejecting ink of each color from each of the plurality of nozzles when the recording medium P held by the transport drum 10 passes a predetermined recording position. Form.

FIG. 2 is a diagram showing an example of the configuration of the nozzle surface 13a of each inkjet head 13. As shown in FIG. 2A, a plurality of ejection units 21 are arranged in a staggered manner on the nozzle surface 13a of the inkjet head 13. As shown in FIG. 2B, a plurality of nozzles 22 for ejecting ink droplets are two-dimensionally arranged on the nozzle surface 13a of each ejection unit 21. As shown in FIG. For example, the ejection unit 21 has a plurality of nozzle rows L1 to L6 in which a plurality of nozzles 22 are arranged at a predetermined interval along a predetermined arrangement direction (specifically, the longitudinal direction (Y direction) of the inkjet head 13). have. FIG. 2B shows an example in which six nozzle rows L1 to L6 are provided on the nozzle surface 13a of the discharge unit 21. In FIG. The intervals between these plurality of nozzle rows L1 to L6 are a predetermined interval W. In this embodiment, the six ejection units 21 having the above configuration are arranged in a staggered manner on the nozzle surface 13a of the inkjet head 13, and the arrangement interval of the plurality of nozzles 22 in the longitudinal direction (Y direction) of the inkjet head 13 is are set so that they are equal. Thereby, the inkjet head 13 can eject ink to the entire area in the width direction (Y direction) of the recording medium P transported by the transport drum 10 to form an image.

Returning to FIG. 1, the fixing unit 14 is provided downstream of the plurality of inkjet heads 13. The fixing unit 14 is arranged over the entire area in the width direction (Y direction) of the recording medium P conveyed by the conveyance drum 10, and irradiates the surface of the recording medium P with energy rays such as ultraviolet rays. The ink ejected by the inkjet head 13 has the property of being cured by energy rays such as ultraviolet rays. Therefore, the fixing unit 14 cures and fixes the ink ejected onto the recording medium P by irradiating the recording medium P with energy rays. As a result, the image formed on the recording medium P is fixed.

The delivery section 15 is provided on the downstream side of the fixing section 14, and holds and picks up one end of the recording medium P conveyed by the conveyance drum 10. The delivery section 15 then passes the recording medium P on which the image has been formed to the medium transport section 7 provided in the medium discharge section 4 .

The medium discharge section 4 includes a medium transport section 7 and a discharge tray 8. The medium transport section 7 transports the recording medium P on which an image has been formed in the image forming section 3 onto the discharge tray 8 . The discharge tray 8 loads the recording medium P conveyed by the medium conveyance section 7 and discharges the recording medium P.

Further, the image forming apparatus 1 configured as described above includes a cleaning device that cleans the nozzle surface 13a on which the plurality of nozzles 22 are arranged in the inkjet head 13. For example, the cleaning device is provided at a position adjacent to the transport drum 10 in the axial direction (Y direction) of the transport drum 10 inside the image forming section 3 .

(Cleaning device)
FIG. 3 is a diagram showing the internal configuration of the image forming section 3 in the YZ plane. As shown in FIG. 3, the cleaning device 30 is provided at a position adjacent to the transport drum 10 in the Y direction orthogonal to the X direction, which is the transport direction of the recording medium P. Further, each inkjet head 13 is provided so as to be movable individually along the axial direction (Y direction) of the transport drum 10. For example, each inkjet head 13 is supported by a ball screw 18 extending in the Y direction at a position where the nozzle surface 13a is spaced a predetermined distance from the outer peripheral side surface of the transport drum 10. A motor 17 is attached to one end of the ball screw 18. The motor 17 rotates the ball screw 18 to move the inkjet head 13 to a position facing the transport drum 10 (the position indicated by the solid line in FIG. 3) and adjacent to the transport drum 10 in the axial direction Y. It is provided so as to be movable between a position facing the cleaning device 30 (a position indicated by a broken line in FIG. 3).

For example, after ejecting ink from the inkjet head 13 to form an image on the recording medium P, the control unit 9 drives the motor 17 at a predetermined timing to move the inkjet head 13 in the axial direction of the transport drum 10 (Y direction). ) to start the cleaning operation. Then, as the inkjet head 13 moves in the Y direction, the cleaning device 30 moves relatively in the longitudinal direction of the inkjet head 13 while in contact with the nozzle surface 13a of the inkjet head 13, and removes ink attached to the nozzle surface 13a. Wipe and clean. In this embodiment, as an example, a configuration will be described in which the cleaning device 30 is moved relatively along the nozzle surface 13a of the inkjet head 13 by moving the inkjet head 13 in the Y direction. However, the present invention is not limited to this, and for example, a configuration may be adopted in which a drive mechanism for moving the cleaning device 30 in the Y direction is separately provided and the control unit 9 controls the drive mechanism.

FIG. 4 is an enlarged sectional view showing the internal structure of the cleaning device 30. Further, FIG. 5 is a perspective view of the cleaning device 30. The cleaning device 30 includes cleaning means for cleaning the nozzle surface 13a of the inkjet head 13. The cleaning means includes a wiping member 31 that wipes the nozzle surface 13a, and wipes the entire nozzle surface 13a by relatively moving the wiping member 31 along the nozzle surface 13a while in contact with the nozzle surface 13a. do. The cleaning device 30 of this embodiment employs a web 32 as the wiping member 31.

As shown in FIG. 4, the cleaning means includes a web 32 which is a wiping member 31, a supply roller 33, and a take-up roller 34. The web 32 is wound around a supply roller 33, and is sequentially and continuously sent out from the supply roller 33, and is wound up and collected by a take-up roller 34. A wiping roller 35 is provided between the supply roller 33 and the take-up roller 34, and the web 32 is hung on the wiping roller 35. The wiping roller 35 is a roller that presses the web 32 sent out from the supply roller 33 against the nozzle surface 13a. Therefore, the cleaning device 30 sequentially and continuously feeds the clean web 32 from the supply roller 33 toward the contact position with the nozzle surface 13a by the wiping roller 35, and at the contact position with the nozzle surface 13a, the web 32 contacts the nozzle surface 13a. It is designed to wipe out. Then, the cleaning device 30 wipes the nozzle surface 13a and collects the web 32 to which the ink is attached by winding it around the take-up roller 34. Such operations of the cleaning device 30 are controlled by the control section 9.

Further, as shown in FIG. 5, the cleaning device 30 sends out and conveys the web 32 in the direction of arrow F2. That is, the conveyance direction of the web 32 (arrow F2 direction) is opposite to the moving direction of the inkjet head 13 (arrow F1 direction). Therefore, the web 32 that has wiped off the nozzle surface 13a is conveyed toward the direction of the nozzle surface 13a that has not been cleaned, thereby suppressing ink adhering to the web 32 from re-adhering to the cleaned nozzle surface 13a. can do.

Further, as shown in FIG. 5, both ends of the wiping roller 35 are pivotally supported by a pressing member 36. The pressing member 36 is constituted by, for example, a solenoid, and moves the wiping roller 35 in the vertical direction. That is, the pressing member 36 adjusts the pressing force of the web 32 against the nozzle surface 13a by moving the wiping roller 35 in the vertical direction. This pressing member 36 is controlled by the control section 9.

Furthermore, as shown in FIG. 5, the cleaning device 30 is provided with a swing mechanism 40 that swings the cleaning device 30 relative to the inkjet head 13. For example, the swing mechanism 40 includes a ball screw 42 that is screwed into the housing of the cleaning device 30 and a motor 41 that is provided at an end of the ball screw 42. This swing mechanism 40 can linearly swing the cleaning device 30 in the direction of arrow F3 orthogonal to the direction of movement of the inkjet head 13 (direction F1). The operation of the swing mechanism 40 is also controlled by the control section 9.

6 and 7 are diagrams illustrating the wiping operation of the nozzle surface 13a by the cleaning device 30. As shown in FIG. 6, the cleaning device 30 brings the web 32 into contact with one end of the nozzle surface 13a as the inkjet head 13 moves in the direction of arrow F1. Thereafter, as the inkjet head 13 moves further in the direction of arrow F1, as shown in FIG. Move relative. At this time, the cleaning device 30 is continuously feeding out the clean web 32 from the supply roller 33 one after another. Therefore, the ink 28 adhering to the nozzle surface 13a is transferred to the web 32 by being wiped by the web 32, and moves toward the conveyance direction of the web 32. As a result, wipe marks 29 of the ink 28 are formed on the surface of the web 32. This wiping mark 29 normally extends toward the conveyance direction of the web 32.

Further, the ink 28 transferred to the web 32 does not immediately move in the conveying direction of the web 32, but enters and remains at a contact position (nip portion) 39 between the web 32 and the nozzle surface 13a for a while. Sometimes. The ink 28 that has entered the contact position 39 between the web 32 and the nozzle surface 13a rubs against the nozzle surface 13a as the contact position 39 moves along the nozzle surface 13a.

FIG. 8 is a diagram showing an example of the wiping marks 29 formed on the web 32. For example, if the swinging mechanism 40 does not swing the cleaning device 30 while the cleaning device 30 is cleaning the nozzle surface 13a, a wiping mark 29 as shown in FIG. 8 is formed on the web 32. . Specifically, the wiping marks 29 formed on the web 32 are formed in the direction in which the plurality of nozzles 22 are arranged. That is, since the web 32 is conveyed in the direction of the arrow F2, the web 32 wipes the periphery of the nozzle 22 located at the leading position P11 in the arrangement direction of the plurality of nozzles 22, thereby causing contact between the web 32 and the nozzle surface 13a. When the ink 28 enters the position 39, the wiping mark 29 extends downstream in the conveyance direction of the web 32 (arrow F2 direction) from the contact position 39 as a base point. Then, when the ink 28 that has entered the contact position 39 between the web 32 and the nozzle surface 13a moves in the conveying direction together with the web 32, there is no ink 28 at the contact position 39, so that the wiping mark 29 is interrupted.

On the other hand, the contact position 39 between the web 32 and the nozzle surface 13a moves along the arrangement direction of the plurality of nozzles 22 while the ink 28 remains at the contact position 39 between the web 32 and the nozzle surface 13a. As time goes on, the wiping trace 29 wipes the area around the nozzle 22 at the second position P12 in the arrangement direction of the plurality of nozzles 22, and further around the nozzle 22 at the third position P13. At this time, the ink 28 that has entered the contact position 39 between the web 32 and the nozzle surface 13a rubs the periphery of the second nozzle 22 and further the periphery of the third nozzle 22, causing wear of the nozzle surface 13a. Become. In the example shown in FIG. 8, the entire width of the wiping mark 29 extending along the conveyance direction of the web 32 covers the entire second nozzle 22 and the third nozzle 22, so the second nozzle The entire periphery of the 22nd and 3rd nozzles 22 will be rubbed by the ink 28 adhering to the web 32, and the degree of wear around the nozzles 22 will increase. Furthermore, if the wipe marks 29 extend further, the influence of the scratches will further spread to the periphery of the subsequent nozzle 22. The reason why the degree of wear around the nozzles 22 increases as described above is that the direction in which the wiping marks 29 extend coincides with the direction in which the plurality of nozzles 22 are arranged.

Therefore, the image forming apparatus 1 of the present embodiment operates the swinging mechanism 40 during the period when the cleaning device 30 is cleaning the nozzle surface 13a to swing the cleaning device 30 with respect to the inkjet head 13. I have to.

FIG. 9 is a diagram showing an example of wiping marks 29 formed on the web 32 when the cleaning device 30 is oscillated. For example, while the cleaning device 30 is cleaning the nozzle surface 13a, the swinging mechanism 40 moves the cleaning device 30 in a direction (direction of arrow F3) perpendicular to the direction of conveyance of the web 32 (direction of arrow F2). When the web 32 is swung, a wiping mark 29 as shown in FIG. 9 is formed on the web 32. Specifically, the wiping marks 29 formed on the web 32 are formed in a direction oblique to the direction in which the plurality of nozzles 22 are arranged. In other words, since the web 32 moves in the vector direction that is the combination of arrows F2 and F3, the wiping marks 29 formed on the web 32 are relative to the arrangement direction of the plurality of nozzles 22 on the nozzle surface 13a of the inkjet head 13. tilt. Therefore, when the ink 28 enters the contact position 39 between the web 32 and the nozzle surface 13a by wiping the periphery of the nozzle 22 located at the leading position P11 in the arrangement direction of the plurality of nozzles 22, the contact position 39 The wiping mark 29 extends diagonally from the starting point on the downstream side in the conveying direction of the web 32 (direction of arrow F2). In this state, when the contact position 39 between the web 32 and the nozzle surface 13a moves along the arrangement direction of the plurality of nozzles 22, the wiping mark 29 is moved to the second position P12 in the arrangement direction of the plurality of nozzles 22. However, as shown in FIG. 9, the wiping trace 29 only covers about half of the nozzle 22 at the second position P12, with about half of the entire width thereof. That is, by tilting the direction in which the wiping marks 29 are formed with respect to the arrangement direction of the plurality of nozzles 22, it is possible to reduce the area where the ink 28 rubs around the nozzle 22 at the second position P12. . Therefore, the degree of wear around the nozzle 22 caused by the wiping marks 29 can be made smaller than in the example shown in FIG. 8 .

However, in FIG. 9, since approximately half of the entire width of the wiping mark 29 wipes approximately half of the nozzles 22 on the downstream side, the ink 28 transferred to the web 32 still scrapes the periphery of the following nozzle 22. It is undeniable that it will be put away. Therefore, in order to prevent the wiping marks 29 formed on the web 32 from wiping the periphery of the following nozzle 22, the cleaning device 30 by the swing mechanism 40 should be It is preferable to make the swinging speed faster.

FIG. 10 is a diagram showing another example of the wiping marks 29 formed on the web 32 when the cleaning device 30 is oscillated. An example is shown in which the rocking speed is faster. As shown in FIG. 10, when the swing speed of the cleaning device 30 by the swing mechanism 40 is faster than the transport speed of the web 32 in the transport direction of the web 32, the wiping marks 29 in the arrangement direction of the plurality of nozzles 22 are The angle of inclination increases. Therefore, for example, by wiping the periphery of the nozzle 22 at the leading positions P11 and P21 in the arrangement direction of the plurality of nozzles 22, the ink 28 enters the contact position 39 between the web 32 and the nozzle surface 13a, and is wiped onto the web 32. Even if a trace 29 is formed, the wipe trace 29 does not wipe the periphery of the nozzle 22 at the following positions P12 and P13. Therefore, it is possible to reduce the degree of wear around the plurality of nozzles 22 arranged on the nozzle surface 13a.

By the way, the length of the wiping mark 29 formed on the web 32 changes depending on how dry the ink 28 adhering to the nozzle surface 13a is when the cleaning device 30 cleans the nozzle surface 13a. If the wiping mark 29 extends further from the example shown in FIG. 10, the wiping mark 29 may reach the position of the adjacent nozzle row and wipe the periphery of the nozzle 22 in the adjacent nozzle row. be. In order to avoid this, for example, it is preferable to reverse the direction of swinging of the cleaning device 30 by the swinging mechanism 40 before the wiping marks 29 formed on the web 32 reach the adjacent nozzle rows. To achieve this, for example, the swing mechanism 40 may swing the cleaning device 30 with a swing width D smaller than the arrangement interval W of the plurality of nozzle rows L1 to L6.

FIG. 11 is a diagram showing another example of the wiping marks 29 formed on the web 32 when the cleaning device 30 is oscillated. An example is shown in which the arrangement interval W of the nozzle rows L1 to L6 is smaller than the interval W. When the swing width D of the cleaning device 30 is made smaller than the arrangement interval W of the nozzle rows L1 to L6, as shown in FIG. 11, the wiping marks 29 formed on the web 32 are wiped off before reaching the adjacent nozzle rows. The inclination direction of the trace 29 is switched. Therefore, it is possible to prevent the remaining ink 28 from entering the contact position 39 between the web 32 and the nozzle surface 13a and wiping out the nozzles 22 of the adjacent nozzle row. In this case, while the cleaning device 30 is cleaning the nozzle surface 13a, the swinging mechanism 40 moves the cleaning device 30 at a certain swing width D that is less than the arrangement interval W between the plurality of nozzle rows L1 to L6. What is necessary is to repeat the operation of reversing the swinging direction.

When the swing direction of the cleaning device 30 is reversed, the movement of the cleaning device 30 in the direction perpendicular to the conveying direction of the web 32 is temporarily stopped. When the cleaning device 30 is moving in the swinging direction, the pressing force of the web 32 against the nozzle surface 13a is distributed in the swinging direction. However, if the cleaning device 30 is temporarily stopped when the swing direction is reversed, the pressing force of the web 32 is not dispersed, so that the pressing force against the nozzle surface 13a temporarily increases. Therefore, the force of rubbing against the nozzle surface 13a by the web 32 increases temporarily, promoting wear of the nozzle surface 13a. The nozzle surface 13a of the inkjet head 13 is treated to be water repellent, and is configured so that the web 32 can easily wipe off ink 28 adhering to the nozzle surface 13a during cleaning. If the rubbing force of the web 32 on the nozzle surface 13a increases temporarily and the water-repellent surface layer of the nozzle surface 13a peels off, the web 32 will not be able to wipe off the ink 28 well during subsequent cleaning. become unable to do so.

Therefore, when reversing the swinging direction of the cleaning device 30, the control unit 9 controls the pressing member 36 to temporarily reduce the pressing force of the web 32 against the nozzle surface 13a. That is, the control unit 9 maintains the pressing force of the web 32 by the pressing member 36 at a predetermined pressure when the cleaning device 30 is moved at a constant speed, and temporarily maintains the pressing force on the web 32 by the pressing member 36 when reversing the swinging direction of the cleaning device 30. Specifically, the pressing force of the web 32 is lowered below a predetermined pressure. This makes it possible to prevent the water-repellent treated surface layer portion of the nozzle surface 13a from peeling off when the swinging direction is reversed.

FIG. 12 is a flowchart showing an example of a processing procedure when the control unit 9 reverses the swinging direction of the cleaning device 30. Upon starting the cleaning operation of the nozzle surface 13a of the inkjet head 13, the control unit 9 drives the swinging mechanism 40 to start swinging the cleaning device 30 (step S10). Then, the control unit 9 determines whether the cleaning device 30 has reached a position where the swing direction is reversed (step S11). When the cleaning device 30 reaches the position where the swing direction is reversed (YES in step S11), the control unit 9 reduces the pressing force by the pressing member 36 from a predetermined pressure (step S12). After that, the control unit 9 reverses the swinging direction of the cleaning device 30 (step S13). After reversing the swinging direction of the cleaning device 30, the control unit 9 returns the pressing force by the pressing member 36 to a predetermined pressure (step S14). Then, the processes of steps S11 to S14 are repeated until the cleaning operation is completed. Thereby, the entire surface of the nozzle surface 13a can be cleaned well without peeling off the surface layer of the nozzle surface 13a that has been subjected to water repellent treatment. Thereafter, when the control unit 9 determines that the cleaning has ended (YES in step S15), it ends the swinging of the cleaning device 30 (step S16).

As described above, the cleaning device 30 of this embodiment continuously sends out the web 32, which is a clean wiping member 31, toward the contact position 39 with the nozzle surface 13a of the inkjet head 13, and uses the web 32 to clean the nozzle surface. 13a, the cleaning device 30 is moved relatively along the arrangement direction of the plurality of nozzles 22 on the nozzle surface 13a, and the cleaning device 30 is swung with respect to the inkjet head 13. As a result, cleaning is performed while the wiping marks 29 formed on the web 32 are inclined with respect to the direction in which the plurality of nozzles 22 are arranged. According to such a configuration, even if the ink 28 enters the contact position 39 between the nozzle surface 13a and the web 32 and the contact position 39 moves in the arrangement direction of the nozzles 22, the wear around the nozzle 22 will be reduced. It is possible to reduce the degree of inkjet head 13 compared to the conventional method, and there is an advantage that the life of the inkjet head 13 can be extended.

(Other configuration examples of the swing mechanism 40)
Next, another example of the structure of the swing mechanism 40 will be described. FIG. 13 is a diagram showing an example of a swing mechanism 40 different from the above. The swinging mechanism 40 shown in FIG. 13 includes a biasing member 48 that presses and biases one side of the cleaning device 30, a cam member 46 that is joined to the other side of the cleaning device 30, and a motor that rotates the cam member 46. 45. The biasing member 48 is formed of, for example, a coil spring, and presses and biases one side surface of the cleaning device 30 in the X direction. The cam member 46 is formed of, for example, an eccentric cam, and is connected to the rotating shaft 45a of the motor 45, and rotates around the rotating shaft 45a. The motor 17 is configured to rotate the cam member 46 and is rotationally driven by the control section 9 . A shaft member 47 that contacts the cam member 46 is provided on the other side of the cleaning device 30 . When the cam member 46 rotates, the contact position between the shaft member 47 and the cam member 46 is displaced in the X direction. This displacement causes the cleaning device 30 to swing linearly in the direction of arrow F3. Therefore, the swinging mechanism 40 for swinging the cleaning device 30 may employ a mechanism as shown in FIG. 13 instead of the mechanism shown in FIG. 5.

FIG. 14 is a diagram illustrating a still different swing mechanism 40. The swing mechanism 40 shown in FIG. 14 is for swinging the cleaning device 30 in a circular manner. In this swing mechanism 40, a motor 44 is provided on the lower surface side of the cleaning device 30, and a rotating shaft 43 of the motor 44 extending in the vertical direction is connected to the cleaning device 30. For example, the rotation shaft 43 of the motor 44 is connected to the center of the bottom surface of the cleaning device 30. The motor 44 is rotationally driven by the control unit 9, and rotates the rotating shaft 43 within a predetermined angle range, thereby causing the cleaning device 30 to pivot. Even when the swing mechanism 40 swings the cleaning device 30 in a circular motion, the same effect as in the linear swing described above can be achieved. Therefore, the swinging mechanism 40 for swinging the cleaning device 30 may employ a mechanism as shown in FIG. 14 instead of the mechanism shown in FIG. 5.

(Other configuration examples of the wiping member 31)
Next, another example of the configuration of the wiping member 31 will be described. FIG. 15 is a diagram showing another example of the configuration of the wiping member 31. The cleaning device 30 shown in FIG. 15 includes a roller 51 as a wiping member 31 that wipes the nozzle surface 13a of the inkjet head 13. The roller 51 wipes the nozzle surface 13a of the inkjet head 13 by rotating in a predetermined direction (R direction) while in contact with the nozzle surface 13a. Further, inside the cleaning device 30, a cleaning member 52 is provided that cleans the surface of the roller 51 by removing ink transferred to the roller 51. For example, the cleaning member 52 is configured by a brush-like roller that comes into contact with the surface of the roller 51 to remove ink from the surface of the roller 51. Therefore, by rotating the shaft portion 51a of the roller 51 in the R direction, the cleaning device 30 sequentially and continuously sends out the clean portion of the roller 51 toward the contact position with the nozzle surface 13a. It is possible to wipe the nozzle surface 13a at the contact position. In this manner, the cleaning device 30 may employ, as the wiping member 31, the roller 51 that can sequentially and continuously send out a clean portion toward the contact position with the nozzle surface 13a.

(Example)
Next, specific examples of the present invention will be described. In this example, the nozzle surface 13a of the inkjet head 13 was cleaned using the cleaning device 30 shown in FIG. The resolution of the inkjet head 13 used was 600 dpi, and the interval between the plurality of nozzle rows L1 to L6 was 1 mm. Further, the speed at which the inkjet head 13 moves in the direction of arrow F1 is 20 mm/s, and the speed at which the web 32 is transported in the direction of arrow F2 is 10 mm/s. Under these conditions, Examples 1 to 3 and Comparative Examples below were carried out.

<Example 1>
As Example 1, from the start to the end of cleaning by the cleaning device 30, the swinging mechanism 40 was driven to swing the cleaning device 30 as shown in FIG. The swinging speed of the cleaning device 30 by the swinging mechanism 40 is 0.4 mm/s, which is slower than the conveyance speed of the web 32.

<Example 2>
As a second embodiment, from the start to the end of cleaning by the cleaning device 30, the cleaning device 30 is oscillated by setting the oscillation width D of the cleaning device 30 to be less than the arrangement interval W of the nozzle rows, as shown in FIG. I let it happen. The swinging speed of the cleaning device 30 by the swinging mechanism 40 is 0.8 mm/s, which is slower than the conveyance speed of the web 32.

<Example 3>
As a third embodiment, from the start to the end of cleaning by the cleaning device 30, the cleaning device 30 is oscillated by setting the oscillating width D of the cleaning device 30 to be less than the arrangement interval W of the nozzle rows, as shown in FIG. I let it happen. The swinging speed of the cleaning device 30 by the swinging mechanism 40 is 12 mm/s, which is faster than the transport speed of the web 32.

<Comparative example>
As a comparative example, the swinging mechanism 40 was not driven and the cleaning device 30 was not swung from the start to the end of cleaning by the cleaning device 30.

<Evaluation>
After carrying out the above Examples 1 to 3 and Comparative Example, the increase ratio of the wear area of the nozzle surface 13a was calculated, and an image was actually formed on the recording medium P to evaluate the image quality. The evaluation results are shown in FIG.

As shown in FIG. 16, in the comparative example, the cleaning device 30 is not oscillated during the cleaning operation, so when the number of cleanings reaches 400 times, the increase ratio of the worn area is 12%, which exceeds 10%. Ta. Furthermore, in the comparative example, deterioration in the quality of the image formed on the recording medium P was detected when the number of cleanings reached 400 times. Therefore, if the cleaning device 30 is not oscillated, it is necessary to replace the inkjet head 13 when the number of cleanings reaches about 400 times.

On the other hand, in Example 1, since the cleaning device 30 is oscillated during the cleaning operation, the number of cleanings in which the increase ratio of the worn area exceeds 10% is 600. Further, in Example 1, when the number of cleanings reached 600 times, deterioration in the quality of the image formed on the recording medium P was detected. Therefore, when the cleaning device 30 is oscillated as in Example 1, it is possible to use the inkjet head 13 for a longer period of time than in the comparative example.

Further, in Example 2, since the cleaning device 30 is oscillated at a faster oscillation speed than in Embodiment 1 during the cleaning operation, the number of times of cleaning at which the increase ratio of the worn area is 10% is 700. Further, in Example 2, when the number of cleanings reached 700 times, deterioration in the quality of the image formed on the recording medium P was detected. Therefore, by swinging the cleaning device 30 as in the second embodiment, it is possible to use the inkjet head 13 for a longer period of time than in the first embodiment.

Furthermore, in Example 3, since the cleaning device 30 is oscillated at a oscillation speed faster than the conveyance speed of the web 32 during the cleaning operation, the increase ratio of the worn area is 7% even when the number of cleanings reaches 1000 times. and was held at less than 10%. Furthermore, in the third embodiment, even when the number of cleanings reaches 1000 times, no deterioration in the quality of the image formed on the recording medium P is detected, so the inkjet head 13 can be used continuously. Therefore, by swinging the cleaning device 30 as in the third embodiment, the inkjet head 13 can be used for a long period of time.

(Modified example)
The preferred embodiments of the present invention have been described above. However, the present invention is not limited to the embodiments described above, and various modifications can be applied.

For example, in the embodiment described above, the example in which the swinging mechanism 40 swings the cleaning device 30 has been described. However, the swinging of the cleaning device 30 only needs to be a relative movement with respect to the inkjet head 13. Therefore, the swing mechanism 40 may be configured to swing the cleaning device 30 relative to the inkjet head 13 by swinging the inkjet head 13.

1 Image forming device 13 Inkjet head 13a Nozzle surface 22 Nozzle 30 Cleaning device 31 Wiping member 32 Web (wiping member)
36 Pressing member (pressing means)
40 Swinging mechanism (swinging means)
51 Roller (wiping member)
L1~L6 nozzle row

Claims (15)

A cleaning device that cleans a nozzle surface in which a plurality of nozzles are arranged in a predetermined arrangement direction in an inkjet head,
A cleaning device is provided that continuously sends out a clean wiping member toward a contact position with the nozzle surface and cleans the nozzle surface with the wiping member, and the cleaning device is relatively moved along the arrangement direction. The cleaning device is also characterized in that the cleaning means is swung relative to the inkjet head to tilt the wiping marks formed on the wiping member with respect to the arrangement direction. The cleaning device according to claim 1, further comprising a swinging device that swings the cleaning device relative to the inkjet head. The nozzle surface is provided with a plurality of nozzle rows arranged in a direction perpendicular to the arrangement direction,
3. The swinging means makes a swinging width smaller than an arrangement interval of the plurality of nozzle rows when swinging the cleaning means relative to the inkjet head. cleaning equipment. 4. The swinging means repeats an operation of swinging the cleaning means relative to the inkjet head by the swinging width during the cleaning operation by the cleaning means. cleaning equipment. The nozzle surface is provided with a plurality of nozzle rows arranged in a direction perpendicular to the arrangement direction,
The swinging means controls the swinging direction of the cleaning means relative to the inkjet head before the wiping mark formed on the wiping member reaches an adjacent nozzle row among the plurality of nozzle rows. The cleaning device according to claim 2, wherein the cleaning device is inverted. 3. The cleaning device according to claim 2, wherein a relative swinging speed of the swinging means is faster than a conveyance speed of the wiping members in the arrangement direction. further comprising pressing means for pressing the wiping member against the nozzle surface at the contact position,
3. The cleaning device according to claim 2, wherein the pressing means reduces the pressing force of the wiping member against the nozzle surface when the direction of rocking by the rocking means is reversed. 3. The cleaning device according to claim 2, wherein the swinging means swings the cleaning means. 9. The cleaning device according to claim 8, wherein the swinging means linearly swings the cleaning means in a direction perpendicular to a sending direction of the wiping member. 9. The cleaning device according to claim 8, wherein the swinging means pivots the cleaning means by rotating the cleaning means within a predetermined angle range. The cleaning device according to claim 2, wherein the swinging means swings the inkjet head. The cleaning device according to claim 1, wherein the wiping member is constituted by a web. The cleaning device according to claim 1, wherein the wiping member includes a roller. An image forming apparatus comprising the cleaning device according to any one of claims 1 to 13. A method for controlling a cleaning device for cleaning a nozzle surface in which a plurality of nozzles are arranged in a predetermined arrangement direction in an inkjet head, the method comprising:
The cleaning device includes a cleaning device that continuously sends out a clean wiping member toward a contact position with the nozzle surface and cleans the nozzle surface with the wiping member,
By moving the cleaning means relatively along the arrangement direction and swinging the cleaning means relative to the inkjet head, the wiping marks formed on the wiping member are removed in the arrangement direction. A control method characterized in that cleaning is performed by the cleaning means while tilting the cleaning means.

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