Cleaning device

Abstract

To provide a cleaning device that improves cleaning accuracy. [Solution] The web 31, including the wiping surface 31a, includes a plurality of first threads 301 extending in the Y direction and second threads 302 extending in the X direction intersecting the Y direction. The wiping surface 31a has a first projection 301a made of the first threads 301 and a second projection 302a made of the second threads 302. The first moving mechanism moves the web 31 and the nozzle surface 13a of the head 13 relative to each other in the Y direction, and the second moving mechanism swings one of the web 31 and the nozzle surface 13s in the X direction. When the wiping surface 31a is in contact with the nozzle surface 13a, the distance between adjacent first projections 301a and second projections 302a in the X direction is M, and when the web 31 wipes the nozzle surface 13a, the distance by which one of the web 31 and the nozzle surface 13a is swung by the second moving mechanism is D, satisfying the condition M ≤ D.

Description

Technical Field

[0006] ,

[0001] The present invention relates to a cleaning device.

Background Art

[0002] Conventionally, there is an inkjet recording apparatus that records an image by ejecting ink from nozzles of a head and landing it at a desired position on a recording medium. When ink adheres to the nozzle surface of the head, the adhered ink thickens and further solidifies while blocking a part of the ejection opening of the nozzle, which may cause poor ink ejection. In the case of aqueous ink, the ink thickens due to evaporation of moisture. In the case of UV ink, the ink thickens when weak ultraviolet light in the surrounding environment is diffusely reflected and hits the UV ink.

[0003] Japanese Unexamined Patent Application Publication No. 2018-79619 (Patent Document 1) discloses a cleaning device that wipes off the ink remaining on the nozzle surface by relatively sliding a fabric cloth and the nozzle surface.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] In an inkjet recording apparatus, improvement of printing image quality is an important issue. Along with this, in a cleaning device as disclosed in the above Patent Document 1, further improvement in cleaning accuracy of the nozzle surface is required.

[0006] Therefore, the present invention has been made to solve the above-described problems, and an object thereof is to provide a cleaning device in which cleaning accuracy is improved. [Means for solving the problem]

[0007] A cleaning device according to the present invention comprises a head, a web, and a moving mechanism. The head has a nozzle surface from which ink can be ejected. The web has a wiping surface for wiping the nozzle surface. The moving mechanism moves the nozzle surface and the web relative to each other. The web includes a plurality of first threads and a plurality of second threads. The plurality of first threads extend along a first direction. The plurality of second threads extend along a second direction intersecting the first direction and are woven into the plurality of first threads. The wiping surface has a plurality of first protrusions and a plurality of second protrusions. The plurality of first protrusions are made up of the plurality of first threads. The plurality of second protrusions are made up of the plurality of second threads. The moving mechanism comprises a first moving mechanism and a second moving mechanism. The first moving mechanism moves the web and the nozzle surface relative to each other along the first direction. The second moving mechanism swings one of the web and the nozzle surface along the second direction. When the wiping surface is in contact with the nozzle surface, let M be the distance between adjacent first and second protrusions in the second direction among the plurality of first and plurality of second protrusions. Also, when the nozzle surface is wiped by the web, let D be the distance that one of the web and the nozzle surface is oscillated by the second moving mechanism. In this case, the cleaning device according to the present invention satisfies the condition M ≤ D. [Effects of the Invention]

[0008] According to the present invention, it is possible to provide a cleaning device that improves cleaning accuracy. [Brief explanation of the drawing]

[0009] [Figure 1] This is a schematic diagram showing the configuration of an image forming apparatus equipped with a cleaning device according to an embodiment. [Figure 2]It is a schematic diagram showing the nozzle surface of the head shown in FIG. 1. [Figure 3] It is an enlarged schematic diagram of one nozzle unit among a plurality of nozzle units shown in FIG. 2. [Figure 4] It is a schematic diagram for explaining the positional relationship between the head and the cleaning device. [Figure 5] It is a schematic perspective view showing the configuration of the cleaning device. [Figure 6] It is a schematic plan view of the web shown in FIG. 5. [Figure 7] It is a schematic cross-sectional view of the web shown in FIG. 6. [Figure 8] It is a schematic diagram for explaining the arrangement of protrusions and valleys on the wiping surface of the web. [Figure 9] It is a schematic diagram for explaining the state of cleaning the head by the cleaning device. [Figure 10] It is a schematic cross-sectional view of the web, nozzle surface, and wiping roller shown in FIG. 9. [Figure 11] It is a flowchart for explaining the flow of processing executed by the control unit during the swinging operation of the cleaning device. [Figure 12] It is a schematic diagram showing the positional relationship between the nozzle surface and the wiping surface of the web in each step shown in FIG. 11. [Figure 13] It is a table showing the test conditions and test results in the verification test. [[ID=Q5]] [Figure 14] It is a schematic diagram showing the configuration of the cleaning device according to the modification.

Embodiments for Carrying Out the Invention

[0010] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the embodiments shown below, the same or common parts are denoted by the same reference numerals in the drawings, and the description thereof will not be repeated.

[0011] (Embodiment) <A. Overall Configuration of the Image Forming Apparatus> FIG. 1 is a schematic diagram showing the configuration of an image forming apparatus including a cleaning device according to an embodiment. Hereinafter, first, referring to FIG. 1, the overall configuration of the image forming apparatus 1 including the cleaning device 30 according to the present embodiment will be described.

[0012] As shown in FIG. 1, the image forming apparatus 1 is an inkjet type image forming apparatus that prints an image on a recording medium P using ink. The ink may be aqueous ink or UV (ultraviolet) ink that is cured by ultraviolet rays. As the recording medium P, for example, various media such as paper such as plain paper or coated paper, cloth, or sheet-like resin can be used, and the ink landing on the main surface of the sheet-like medium can be fixed.

[0013] The image forming apparatus 1 includes a paper feeding unit 2, an image forming unit 3, and a paper discharging unit 4. The recording medium P is conveyed in the order of the paper feeding unit 2, the image forming unit 3, and the paper discharging unit 4.

[0014] In the following, as shown in FIG. 1, the direction in which the paper feeding unit 2, the image forming unit 3, and the paper discharging unit 4 are arranged and in which the recording medium P is conveyed is also referred to as the X direction. Further, the horizontal direction orthogonal to the X direction is also referred to as the Y direction. Furthermore, the vertical direction orthogonal to both the X direction and the Y direction is also referred to as the Z direction.

[0015] The paper feeding unit 2 has a paper feeding tray 5 and a first conveying unit 6. The recording medium P is stacked on the paper feeding tray 5. The first conveying unit 6 conveys the recording medium P on the paper feeding tray 5 to the image forming unit 3 one by one.

[0016] Based on a command from the control unit 9, the paper feeding unit 2 first takes out one recording medium P located at the uppermost surface among the recording media P placed on the paper feeding tray 5. Next, the paper feeding unit 2 conveys the recording medium P to the image forming unit 3 by the first conveying unit 6. The control unit 9 will be described later.

[0017] The image forming unit 3 uses ink to form (print) an image based on image data onto the recording medium P. The image forming unit 3 includes a first transfer unit 10, a transport drum 11, a heating unit 12, a plurality of heads 13, a fixing unit 14, and a second transfer unit 15.

[0018] The first transfer unit 10 receives the recording medium P being transported by the first transport unit 6 of the paper feeding unit 2 and transfers the recording medium P to the transport drum 11. For example, the first transfer unit 10 first holds and picks up one end of the recording medium P being transported from the first transport unit 6. Next, the first transfer unit 10 transports the recording medium P along the outer surface of the transport drum 11. Then, the first transfer unit 10 transfers the recording medium P to the transport drum 11 so that the transport drum 11 can hold the recording medium P by attraction.

[0019] The transport drum 11 is a component that transports the recording medium P. The transport drum 11 has, for example, a cylindrical shape, but it may also have a cylindrical shape or the like. The outer circumferential surface of the transport drum 11 is configured as an adsorption surface that adsorbs and holds the recording medium P.

[0020] The first transfer unit 10, the heating unit 12, the multiple heads 13, the fixing unit 14, and the second transfer unit 15 are arranged in this order along the circumferential direction of the transfer drum 11, facing the transfer drum 11. The transfer drum 11 rotates with the recording medium P adsorbed and held on its outer surface. As a result, the recording medium P is sequentially transported to a position facing each of the heating unit 12, the multiple heads 13, the fixing unit 14, and the second transfer unit 15.

[0021] The heating unit 12 is located downstream of the transfer unit 10 in the transport direction of the recording medium P. The heating unit 12 heats the recording medium P so that its surface reaches a temperature within a predetermined temperature range. The heating unit 12 includes a heater, such as an infrared heater. The heating unit 12 heats the recording medium P by driving the heater based on a command from the control unit 9.

[0022] Multiple heads 13 are located downstream of the heating unit 12 in the transport direction of the recording medium P. In this embodiment, four heads 13 are arranged in a line along the circumferential direction of the transport drum 11. The four heads 13 eject Y (yellow), M (magenta), C (cyan), and K (black) inks, respectively.

[0023] Each head 13 has a nozzle surface 13a on which multiple nozzles are arranged. Each head 13 is positioned such that the nozzle surface 13a is spaced a predetermined distance from the outer circumferential surface of the transport drum 11. In this embodiment, each head 13 is configured not to move in the transport direction of the recording medium P.

[0024] Each head 13 ejects ink toward the recording medium P, which is transported by the transport drum 11. This forms an image on the recording medium P. The configuration of the heads 13 will be described in detail later.

[0025] The fixing unit 14 is located downstream of the multiple heads 13 in the transport direction of the recording medium P. If the ink has the property of hardening when exposed to energy rays such as ultraviolet light, the fixing unit 14 irradiates the surface of the recording medium P with energy rays such as ultraviolet light. As a result, the ink ejected onto the recording medium P hardens, and the image formed on the recording medium P is fixed to the recording medium P.

[0026] The second transfer unit 15 is located downstream of the fixing unit 14 in the transport direction of the recording medium P. The second transfer unit 15 receives the recording medium P transported by the transport drum 11 and passes the recording medium P to the paper discharge unit 4. For example, the second transfer unit 15 first holds and picks up one end of the recording medium P transported by the transport drum 11. Next, the second transfer unit 15 passes the recording medium P with the image fixed to it to the second transport unit 7 of the paper discharge unit 4.

[0027] The paper output unit 4 includes a second transport unit 7 and a paper output tray 8. The second transport unit 7 transports the printed recording media P, which have been transported from the image forming unit 3, one sheet at a time to the paper output tray 8. The paper output tray 8 loads the recording media P transported by the second transport unit 7 and also discharges them.

[0028] The image forming apparatus 1 further comprises a control unit 9, a cleaning device 30, and a moving mechanism.

[0029] The control unit 9 has as its main components a CPU (Central Processing Unit), memory, and input / output devices (not shown) for inputting and outputting various signals. The control unit 9 controls the operation of each component, such as the paper feeding unit 2, image forming unit 3, paper discharge unit 4, cleaning device 30, and moving mechanism.

[0030] The CPU executes programs. Memory includes ROM (Read Only Memory) and RAM (Random Access Memory). ROM stores data non-volatilely. RAM stores data generated by the CPU's program execution volatilely.

[0031] Each component of the control unit 9 is connected to the others by a data bus. Processing in the CPU is realized by each piece of hardware and software executed by the CPU. Such software is pre-stored in ROM / RAM. The control unit 9 is powered by an internal power supply (not shown) or an external power supply (not shown). For connection to the external power supply, for example, an AC adapter (not shown) is used.

[0032] The cleaning device 30 cleans the nozzle surfaces 13a of multiple heads 13 using a web 31. The cleaning device 30 is positioned adjacent to the transport drum 11 in the Y direction (see Figure 4, which will be described later). The configuration of the cleaning device 30 will be described in detail later.

[0033] The moving mechanism relatively moves the nozzle surface 13a of the head 13 and the web 31. Specifically, the moving mechanism has a first moving mechanism 40 and a second moving mechanism 50. The first moving mechanism 40 relatively moves the web 31 and the nozzle surface 13a along the Y direction. The second moving mechanism 50 swings one of the web 31 and the nozzle surface 13a along the X direction. The first moving mechanism 40 and the second moving mechanism 50 will be described in detail later.

[0034] <B. Detailed Configuration of the Head> FIG. 2 is a schematic diagram showing the nozzle surface of the head shown in FIG. 1. FIG. 3 is an enlarged schematic diagram of one of the plurality of nozzle units shown in FIG. 2. FIG. 4 is a schematic diagram for explaining the positional relationship between the head and the cleaning device. Next, the detailed configuration of the head 13 will be described with reference to FIGS. 2 to 4.

[0035] As shown in FIGS. 2 and 3, the head 13 has a nozzle surface 13a capable of discharging ink. The nozzle surface 13a has a substantially rectangular shape when viewed from the bottom. A plurality of nozzle units 21 are arranged in a staggered pattern on the nozzle surface 13a.

[0036] In each nozzle unit 21, a plurality of nozzles 22 capable of discharging ink are two-dimensionally arranged. In the present embodiment, the nozzle unit 21 is provided with six nozzle rows each composed of a plurality of nozzles 22 arranged linearly at a first pitch interval p1 along a predetermined arrangement direction. The six nozzle rows are arranged at a second pitch interval p2 in a direction orthogonal to the above arrangement direction. In the present embodiment, the above arrangement direction corresponds to the third direction, and the direction orthogonal to the above arrangement direction corresponds to the fourth direction. The above arrangement direction coincides with the Y direction. The direction orthogonal to the above arrangement direction coincides with the X direction.

[0037] The position of a nozzle 22 in one of two adjacent nozzle rows is offset in the V direction by a third pitch spacing p3 from the position of a nozzle 22 in the other of the two adjacent nozzle rows. The position in the V direction of one nozzle 22 in any nozzle row does not coincide with the position in the V direction of any other nozzle 22 in the remaining nozzle rows. For example, if the resolution of the head 13 is 1200 dpi, the first pitch spacing p1 is 126 μm, the second pitch spacing p2 is 42 μm, the third pitch spacing p3 is 42 μm, and the dimension p4 shown in Figure 3 is 21 μm.

[0038] The nozzle surface 13a is treated with a water-repellent coating. This makes it easier for ink adhering to the nozzle surface 13a to be wiped away by the web 31 when cleaning the nozzle surface 13a using the web 31.

[0039] When the head 13 ejects ink onto the recording medium P, the head 13 is positioned such that the longitudinal direction of the nozzle surface 13a (the Y direction in Figure 2) coincides with the width direction of the recording medium P being transported by the transport drum 11. With the head 13 configured in this way, ink can be ejected over the entire width of the recording medium P being transported by the transport drum 11.

[0040] As shown in Figure 4, each of the multiple heads 13 is provided with a first moving mechanism 40. The first moving mechanism 40 is configured to move the head 13 along the axial direction (Y direction) of the conveying drum 11.

[0041] In detail, the first moving mechanism 40 includes a ball screw 41 and a motor 42. The ball screw 41 extends along the Y direction. The head 13 is supported by the ball screw 41 such that the nozzle surface 13a is positioned at a predetermined distance from the outer circumferential surface of the conveying drum 11. The motor 42 is attached to one axial end of the ball screw 41.

[0042] By driving the motor 42, the control unit 9 rotates the ball screw 41. As a result, the head 13 can move between a position facing the outer peripheral surface of the conveyance drum 11 (i.e., the position indicated by the solid line in FIG. 4) and a position facing the cleaning device 30 (i.e., the position indicated by the dashed line in FIG. 4).

[0043] Note that the configuration of the first moving mechanism 40 described above is merely an example and is not limited to this configuration. The first moving mechanism 40 only needs to be configured such that the head 13 can move between two positions as described above. Also, the first moving mechanism 40 may be configured to be able to move the web 31 along the Y direction.

[0044] <C. Detailed Configuration of Cleaning Device> FIG. 5 is a schematic perspective view showing the configuration of the cleaning device. FIG. 6 is a schematic plan view of the web shown in FIG. 5. FIG. 7 is a schematic cross-sectional view of the web taken along line VII-VII in FIG. 6. FIG. 8 is a schematic diagram for explaining the arrangement of protrusions and valleys on the wiping surface of the web. Next, with reference to FIGS. 5 to 8 and the aforementioned FIG. 4, the detailed configuration of the cleaning device 30 according to the present embodiment will be described. In FIG. 8, the first yarn 301 is shaded with dense dot hatching, and the second yarn 302 is shaded with sparse dot hatching. Also, in FIG. 8, the protrusions mp are shown as circles drawn with solid lines, and the valleys vp are shown as circles drawn with dashed lines. Note that the planar shape of each of the protrusions mp and valleys vp is not particularly limited to a circular shape. The protrusions mp and valleys vp will be described later.

[0045] As shown in FIGS. 4 to 8, the cleaning device 30 mainly includes a web 31, a supply roller 32, a take-up roller 33 as a take-up mechanism, and a wiping roller 34. The cleaning device 30 is a device for cleaning the nozzle surface 13a of the head 13.

[0046] The web 31 has a long roll shape. The longitudinal direction of the web 31 coincides with the Y direction.

[0047] The web 31 includes a plurality of first threads 301 and a plurality of second threads 302. The plurality of first threads 301 extend along the Y direction. The plurality of second threads 302 extend along the X direction. The plurality of second threads 302 are woven into the plurality of first threads 301. In this embodiment, the Y direction corresponds to the first direction, and the X direction corresponds to the second direction.

[0048] The web 31 has a wiping surface 31a that wipes the nozzle surface 13a. The wiping surface 31a has a plurality of first protrusions 301a, which are composed of a plurality of first threads 301, and a plurality of second protrusions 302a, which are composed of a plurality of second threads 302. In the portion of the wiping surface 31a between adjacent first protrusions 301a and second protrusions 302a in the X direction, and in the portion between adjacent first protrusions 301a and second protrusions 302a in the Y direction, there is a valley vp where neither the first protrusions 301a nor the second protrusions 302a are present. When the first protrusions 301a and second protrusions 302a are not distinguished, they may be referred to as protrusions mp.

[0049] In this embodiment, a plain weave fabric is used as the web 31. Therefore, multiple first threads 301 and multiple second threads 302 are woven alternately. Consequently, the protrusions mp and valleys vp are alternately located along the X and Y directions on the wiping surface 31a.

[0050] The web 31 is wound in a roll onto the supply roller 32. The web 31 is then wound onto the take-up roller 33. A wiping roller 34 is located between the supply roller 32 and the take-up roller 33. The web 31 is placed over the wiping roller 34. Of the pair of main surfaces of the web 31, the main surface opposite to the wiping roller 34 defines the wiping surface 31a that wipes the nozzle surface 13a of the head 13.

[0051] The web 31 wipes the nozzle surface 13a by moving the wiping surface 31a relative to the nozzle surface 13a while the wiping surface 31a is in contact with the nozzle surface 13a.

[0052] The wiping roller 34 is used to press the web 31, which is fed from the supply roller 32, toward the nozzle surface 13a. In detail, as shown in Figure 5, the wiping roller 34 is pivotally supported at both axial ends by pressing members 35. The pressing members 35 move the wiping surface 31a toward the nozzle surface 13a. This adjusts the pressing force of the web 31 toward the nozzle surface 13a. For example, a solenoid can be used as the pressing member 35. The operation of the pressing member 35 is controlled by the control unit 9.

[0053] When the wiping surface 31a is in contact with the nozzle surface 13a, the first projection 301a, which is made of the first thread 301, and the second projection 302a, which is made of the second thread 302, are crushed by being sandwiched between the nozzle surface 13a and the wiping roller 34 (see Figure 10, which will be described later).

[0054] In the cleaning device 30, a clean web 31 is sequentially and continuously fed from the supply roller 32 toward the nip portion np formed by the opposing nozzle surfaces 13a and the wiping roller 34. Next, the nozzle surface 13a is wiped by the web 31 at the nip portion np. Then, the web 31, to which ink has adhered after wiping the nozzle surface 13a, is recovered by being wound onto the winding roller 33 in the Y direction. This configuration makes it possible to always wipe the nozzle surface 13a with a clean web 31. The operation of each component of the cleaning device 30 is controlled by the control unit 9.

[0055] As shown in Figure 5, the cleaning device 30 further includes a second moving mechanism 50. The second moving mechanism 50 oscillates the web 31 along the X direction, which is the direction intersecting the Y direction, which is the direction of movement of the nozzle surface 13a. The operation of this second moving mechanism 50 is controlled by the control unit 9.

[0056] The oscillation of the web 31 by the second moving mechanism 50 is a fine motion including at least any one of single oscillation, reciprocating motion, elliptical motion, and circular motion.

[0057] As the second moving mechanism 50, for example, a piezo actuator, a solenoid actuator as an electromagnetic actuator using an electromagnet, a parallel plate type electrostatic actuator using electrostatic force, a comb type electrostatic actuator using electrostatic force, etc. can be used. In addition to this, as the second moving mechanism 50, a method of vibrating by driving an eccentric cam with a motor, a method of vibrating by a linear motor, etc. can also be adopted.

[0058] When a piezo actuator is used as the second moving mechanism 50, the oscillation distance can be managed with high accuracy. When a solenoid actuator is used as the second moving mechanism 50, low cost can be achieved. When an electrostatic actuator is used as the second moving mechanism 50, a second moving mechanism 50 that is small and highly durable can be obtained. In the present embodiment, a piezo actuator is used as the second moving mechanism 50.

[0059] Note that the second moving mechanism 50 may be provided on the head 13. In this case, the nozzle surface 13a is oscillated in the X direction by the second moving mechanism 50.

[0060] When the second moving mechanism 50 is provided on the housing of the cleaning device 30 as in the present embodiment, the second moving mechanism 50 can be miniaturized compared to the case where the second moving mechanism 50 is provided on the head 13. This is because the housing of the cleaning device 30 is smaller than the head 13. <D. Cleaning of the nozzle surface by the cleaning device>

[0061] Figures 9(A) and 9(B) are schematic diagrams illustrating the cleaning of the head by the cleaning device. Figure 10 is a schematic cross-sectional view of the web, nozzle surface, and wiping roller along line XX in Figure 9(B). Figure 11 is a flowchart illustrating the flow of processing performed by the control unit during the oscillating motion of the cleaning device. Figures 12(A) to 12(C) are schematic diagrams showing the positional relationship between the nozzle surface and the wiping surface of the web at each step shown in Figure 11. Next, a method for cleaning the nozzle surface 13a of the head 13 using the cleaning device 30 according to this embodiment will be described with reference to Figures 9 to 12 and the aforementioned Figures 4 and 5. In Figures 12(A) to 12(C), the nozzle surface is shown as a perspective view from above. Also, in Figures 12(A) to 12(C), only the protrusions mp and valleys vp of the web 31 are schematically shown in the same manner as in Figure 8.

[0062] As shown in Figures 4, 5 and 9(A), when cleaning the nozzle surface 13a of the head 13 using the cleaning device 30, the control unit 9 first moves the head 13 along the Y direction.

[0063] In detail, after the head 13 ejects ink to form an image on the recording medium P, the control unit 9 drives the motor 42 of the first moving mechanism 40. As a result, the head 13 begins to move along the Y direction from a position facing the outer surface of the transport drum 11 to a position facing the cleaning device 30 (see arrow F1 in Figures 4, 5 and 9(A)).

[0064] As shown in Figure 9(B), one end of the nozzle surface 13a of the head 13, which has been moved to a position facing the cleaning device 30, in the Y direction, comes into contact with the wiping surface 31a of the web 31 of the cleaning device 30. More specifically, the wiping surface 31a of the web 31 is pressed against one end of the nozzle surface 13a by the wiping roller 34.

[0065] With one end of the nozzle surface 13a in contact with the wiping surface 31a, the head 13 moves further in the Y direction (see arrow F1 in Figure 9(B)). As a result, the ink 28 is wiped away by the web 31 sequentially from one end of the nozzle surface 13a to the other.

[0066] Preferably, the control unit 9 drives the winding roller 33 to collect the web 31 while the web 31 and nozzle surface 13a are moving relative to each other by the first moving mechanism 40. More specifically, it is preferable that the web 31 is wound up by the winding roller 33 at least from the time when wiping of the nozzle surface 13a by the web 31 begins until wiping of the entire nozzle surface 13a is completed.

[0067] As a result, during cleaning of the nozzle surface 13a using the web 31, the web 31 is fed in the F2 direction (see Figure 5), which is the opposite direction to the F1 direction relative to the nozzle surface 13a. In other words, the portion of the web 31 that has wiped the nozzle surface 13a moves toward the portion of the nozzle surface 13a that has not yet been cleaned. As a result, it is possible to effectively prevent the ink 28 adhering to the web 31 from adhering again to the portion of the nozzle surface 13a that has already been cleaned.

[0068] Here, as shown in Figure 10, when cleaning the nozzle surface 13a with the cleaning device 30, it is preferable that the nozzle surface 13a comes into contact with the first projection 301a or the second projection 302a of the wiping surface 31a. This is because the contact area between the first projection 301a and the nozzle surface 13a, and the contact area between the second projection 302a and the nozzle surface 13a are larger than the contact area between the valley portion vp of the wiping surface 31a and the nozzle surface 13a.

[0069] In this regard, the cleaning device 30 according to this embodiment includes, as described above, a second moving mechanism 50 that swings the web 31 along the X direction while the web 31 and nozzle surface 13a are moving relative to each other by the first moving mechanism 40. The control unit 9 operates the second moving mechanism 50 to swing the web 31 along the X direction at least from the time when wiping the nozzle surface 13a by the web 31 begins until wiping the entire surface of the nozzle surface 13a is completed.

[0070] This configuration makes it possible to improve the cleaning accuracy of the cleaning device 30. The oscillation operation of the web 31 in the cleaning device 30 will be described in detail below with reference to Figures 10 to 12.

[0071] First, as shown in Figures 11 and 12(A), in step S10, the control unit 9 starts the swinging of the web 31. More specifically, the control unit 9 operates the second movement mechanism 50 while moving the head 13 along the Y direction (see arrow F1 in Figure 12(A)). This causes the web 31 to move along the X direction. For convenience of explanation, this direction of movement of the web 31 will also be referred to as the X1 direction. The distance D that the web 31 moves in the X1 direction (see Figures 12(A) to 12(C)) will be described in detail later.

[0072] Next, as shown in Figure 11, in step S11, the control unit 9 determines whether the web 31 has reached a position where it reverses its direction of oscillation. If it is determined that the web 31 has reached a position where it reverses its direction of oscillation (YES in step S11), the control unit 9 proceeds to step S12. If it is determined that the web 31 has not reached a position where it reverses its direction of oscillation (NO in step S11), the control unit 9 moves the web 31 along the X1 direction by operating the second moving mechanism 50.

[0073] Next, as shown in Figure 11, in step 12, the control unit 9 operates the pressing member 35. This reduces the pressing force of the web 31 against the nozzle surface 13a from a predetermined pressure.

[0074] Next, as shown in Figures 11, 12(B), and 12(C), in step 13, the control unit 9 reverses the direction of oscillation of the web 31. Specifically, the control unit 9 moves the web 31 along the X2 direction, which is opposite to the X1 direction, by operating the second moving mechanism 50.

[0075] Next, as shown in Figure 11, in step 14, the control unit 9 increases the pressing force of the web 31 against the nozzle surface 13a by operating the pressing member 35. This returns the pressing force to the predetermined pressure.

[0076] Next, as shown in Figure 11, in step S15, the control unit 9 determines whether or not cleaning of the nozzle surface 13a using the web 31 is complete. If it is determined that cleaning is complete (YES in step S15), the control unit 9 proceeds to step S16 to end the oscillation of the web 31. If it is determined that cleaning is not complete (NO in step S15), the control unit 9 repeats steps S11 to S14 described above.

[0077] Here, while the web 31 is moving in the oscillation direction, the pressing force of the web 31 against the nozzle surface 13a is distributed in the oscillation direction. On the other hand, when the oscillation direction of the web 31 reverses and the web 31 pauses, the pressing force of the web 31 is no longer distributed. Therefore, if the pressing force of the web 31 against the nozzle surface 13a is maintained at a predetermined pressure at the position where the oscillation direction of the web 31 reverses, the pressing force against the nozzle surface 13a will temporarily increase, and there is a risk that the water-repellent surface layer of the nozzle surface 13a will peel off. If peeling occurs in this manner on the surface layer of the nozzle surface 13a, the cleaning accuracy of the ink 28 by the web 31 will decrease.

[0078] In this embodiment, as described above, while the web 31 is moving in the oscillation direction, the pressing force of the web 31 is maintained at a predetermined pressure, and at the position where the oscillation direction of the web 31 is reversed, the pressing force of the web 31 against the nozzle surface 13a is reduced from the predetermined pressure. This makes it possible to clean the entire surface of the nozzle surface 13a effectively without peeling off the water-repellent treated surface layer of the nozzle surface 13a.

[0079] Furthermore, in this embodiment, when the dimension of the nozzle surface 13a in the Y direction that contacts the wiping surface 31a is Wni, the relative movement speed of the nozzle surface 13a with respect to the web 31 along the Y direction is Sf, the oscillation speed of the web 31 along the X direction is Sy, and the diameter of the nozzle provided on the nozzle surface 13a is d, the cleaning device 30 operates such that (Wni+d) / Sf≧2D / Sy.

[0080] This allows the web 31 to oscillate at least once back and forth within the time it takes for the nozzle surface 13a to pass through the nip portion np. Therefore, the cleaning accuracy of the nozzle surface 13a by the cleaning device 30 can be improved.

[0081] As shown in Figure 10, when the wiping surface 31a is in contact with the nozzle surface 13a, the first projection 301a, which is made of the first thread 301, and the second projection 302a, which is made of the second thread 302, are crushed by being sandwiched between the nozzle surface 13a and the wiping roller 34.

[0082] In this state, the first projection 301a and the second projection 302a, which are adjacent in the X direction, are separated by a predetermined distance. If the distance between them is M, and the distance the web 31 is oscillated by the second moving mechanism 50 when the web 31 wipes the nozzle surface 13a is D, the second moving mechanism 50 oscillates the web 31 such that the condition M ≤ D is satisfied.

[0083] This configuration ensures that the nozzle surface 13a is reliably brought into contact with at least one of the first projection 301a and the second projection 302a of the wiping surface 31a while the nozzle surface 13a is being wiped by the web 31. In other words, it effectively prevents the nozzle surface 13a from passing only through the valleys vp of the wiping surface 31a in any part of the nozzle surface 13a. As a result, the cleaning accuracy of the nozzle surface 13a by the cleaning device 30 can be dramatically improved.

[0084] Therefore, by using the cleaning device 30 according to this embodiment, it is possible to create a cleaning device that improves cleaning accuracy.

[0085] Furthermore, the effect of improving the cleaning accuracy of the cleaning device 30 described above has been confirmed by verification tests described later.

[0086] Furthermore, in this embodiment, when the wiping surface 31a is in contact with the nozzle surface 13a, and the dimension in the X direction of one of the multiple second protrusions 302a is N (see Figure 10), it is preferable that the second moving mechanism 50 swings the web 31 so as to satisfy the condition D ≤ M + N. By configuring it in this way, the operating load of the cleaning device 30 can be reduced, and deterioration of the water-repellent coating applied to the nozzle surface 13a can be effectively suppressed.

[0087] Furthermore, in the cleaning device 30 according to this embodiment, as described above, plain woven fabric is used as the web 31. By configuring it in this way, the cleaning device 30 can be made smaller and less expensive compared to, for example, when twill woven fabric is used as the web 31. This is because the thickness of plain woven fabric is about 2 / 3 that of twill woven fabric, so the components of the cleaning device 30, such as the supply roller 32, winding roller 33, and wiping roller 34, can be made smaller. Also, plain woven fabric is less expensive than twill woven fabric.

[0088] In the cleaning device 30 according to the above-described embodiment, although the case where the second moving mechanism 50 swings the web 31 has been exemplified, the second moving mechanism 50 may be configured to swing the nozzle surface 13a of the head 13.

[0089] Also, in the cleaning device 30 according to the above-described embodiment, although a plain woven fabric is used as the web 31, the web 31 may be, for example, a twill woven fabric.

[0090] Furthermore, in the cleaning device 30 according to the above-described embodiment, although the case where the head 13 is configured not to move in the conveyance direction of the recording medium P has been exemplified, the head 13 may be configured to be movable in the conveyance direction of the recording medium P. In this case, the size of the head 13 in the X direction can be reduced.

[0091] Also, in this case, the cleaning device 30 may be disposed at a position upstream or downstream of the head 13 in the conveyance direction of the recording medium P. The cleaning device 30 is disposed such that the feeding direction of the web 31 coincides with the direction (i.e., the X direction) orthogonal to the arrangement direction of the plurality of nozzles 22. Specifically, the arrangement direction of the plurality of nozzles 22 coincides with the extending direction of the second yarn 302, and the direction orthogonal to the arrangement direction coincides with the extending direction of the first yarn 301. Then, the first moving mechanism 40 moves one of the head 13 and the web 31 in the X direction, and the second moving mechanism 50 swings one of the head 13 and the web 31 in the Y direction. When configured in this way, further miniaturization of the device can be achieved.

[0092] <E. Verification Test> In the verification test, verification was performed to clarify the relationship between the presence or absence of swinging by the second moving mechanism 50 and the swinging speed of the web 31 by the second moving mechanism 50, and the cleaning accuracy. FIG. 13 is a table showing the test conditions and test results in the verification test.

[0093] First, the test conditions common to all of Example 1, Example 2, and Comparative Example 1 will be described. The resolution of the head 13 used in this verification test is 1200 dpi. The nozzle diameter d is 30 μm. The movement speed of the head 13 along the F1 direction (i.e., the relative movement speed Sf of the nozzle surface 13a with respect to the web 31 along the Y direction) is 20 mm / s. The feed speed of the web 31 along the F2 direction is 10 mm / s. Therefore, the relative movement speed Sf of the nozzle surface 13a with respect to the web 31 along the Y direction is 30 mm / s. The hardness of the wiping roller 34 is Asker C7. The pressing force of the pressing member 35 is 5 kPa. The dimension Wni in the Y direction of the nip portion np is 1 mm. Plain woven fabric is used as the web 31. The distance M when the wiping surface 31a of the web 31 is in contact with the nozzle surface 13a is 60 μm, and the dimension N is 60 μm. The distance D over which the web 31 is oscillated by the second movement mechanism 50 is 60 μm.

[0094] In Example 1, the oscillation speed Sy of the web 31 by the second moving mechanism 50 is 2.3 mm / s. This causes the web 31 to oscillate once back and forth within the time it takes for the nozzle surface 13a to pass the nip portion np. In Example 2, the oscillation speed Sy is 12 mm / s. In Comparative Example 1, the oscillation of the web 31 by the second moving mechanism 50 was not performed.

[0095] After performing the cleaning described in Example 1, Example 2, and Comparative Example 1, the nozzle surface 13a was observed under a microscope to visually confirm the cleaning accuracy of the peripheral portion of the nozzle 22. The results of the visual inspection are shown in Figure 13.

[0096] In Figure 13, "Excellent" indicates that almost no ink remains fixed around the nozzle 22, "Good" indicates that some ink remains around the nozzle 22 but is mostly removed, and "Poor" indicates that a considerable amount of ink remains fixed around the nozzle.

[0097] As shown in Figure 13, the visual inspection of the nozzle surface 13a after cleaning was good in Examples 1 and 2. On the other hand, the visual inspection of the nozzle surface 13a after cleaning was poor in Comparative Example 1. From these results, it was confirmed that the cleaning accuracy can be improved by oscillating the web 31 by the second moving mechanism 50 so as to satisfy the condition M ≤ D. Furthermore, it was confirmed that the cleaning accuracy can be further improved by increasing the reciprocating movement of the web 31.

[0098] (modified version) Figure 14 is a schematic diagram showing the configuration of a modified cleaning device. The following description of the modified cleaning device 30A based on the above-described embodiment will refer to Figure 14. Note that in Figure 14, the cleaning device 30A is viewed along the Y direction.

[0099] As shown in Figure 14, the cleaning device 30A according to this modified example differs from the cleaning device 30 according to the embodiment described above only in the configuration of the second moving mechanism 50A.

[0100] In detail, the second moving mechanism 50A includes a biasing member 51, a shaft member 52, a cam member 53, and a motor 54.

[0101] The biasing member 51 presses and biases one of a pair of opposing sides of the housing of the cleaning device 30A toward the other side. For example, a coil spring can be used as the biasing member 51.

[0102] The shaft member 52 is mounted on the other side of the cleaning device 30A so as to protrude from the other side of a pair of sides. The cam member 53 is positioned so that its surface abuts against the shaft member 52. The motor 54 includes a rotating shaft 54a. The cam member 53 is fixed to the rotating shaft 54a. The cam member 53 is configured to rotate around the axis of the rotating shaft 54a by the driving force of the motor 54. The drive of the motor 54 is controlled, for example, by the control unit 9. For example, an eccentric cam is used as the cam member 53.

[0103] As the motor 54 is driven, the cam member 53 rotates, causing the contact point between the shaft member 52 and the cam member 53 to be displaced along the X direction. This allows the second moving mechanism 50A to linearly oscillate the housing of the cleaning device 30A having the web 31 along the X direction (see arrow F3 in the figure).

[0104] Even with this configuration, effects similar to those described in the above-described embodiment can be obtained, resulting in a cleaning device with improved cleaning accuracy.

[0105] (Note) The characteristic configuration of the cleaning apparatus disclosed in the above-described embodiment and its modified form can be summarized as follows:

[0106] [Note 1] A head having a nozzle surface capable of ejecting ink, A web having a wiping surface for wiping the nozzle surface, The system includes a moving mechanism that moves the nozzle surface and the web relative to each other. The web described above includes a plurality of first threads extending along a first direction, and a plurality of second threads extending along a second direction intersecting the first direction and woven into the plurality of first threads. The wiping surface has a plurality of first protrusions composed of the plurality of first threads and a plurality of second protrusions composed of the plurality of second threads, The above-described moving mechanism comprises a first moving mechanism that moves the web and the nozzle surface relative to each other along the first direction, and a second moving mechanism that swings one of the web and the nozzle surface along the second direction. A cleaning device that satisfies the condition M ≤ D, where M is the distance between adjacent first and second protrusions in the second direction among the plurality of first protrusions and the plurality of second protrusions when the wiping surface is in contact with the nozzle surface, and D is the distance by which one of the web and the nozzle surface is oscillated by the second moving mechanism when the web wipes the nozzle surface.

[0107] [Note 2] The cleaning device described in Appendix 1, wherein, when the wiping surface is in contact with the nozzle surface, the dimension of one of the plurality of second protrusions in the second direction is N, and the condition D ≤ M + N is satisfied.

[0108] [Note 3] The above web is a plain weave fabric, as described in Appendix 1 or 2 of the cleaning apparatus.

[0109] [Note 4] The cleaning device described in any one of the appendices 1 to 3, wherein the second direction described above is perpendicular to the first direction described above.

[0110] [Note 5] A cleaning device according to any one of the appendices 1 to 4, wherein (Wni+d) / Sf≧2D / Sy is satisfied when Wni is the dimension of the nozzle surface in the first direction of the portion that contacts the wiping surface, Sf is the relative movement speed of one of the web and the nozzle surface with respect to the other along the first direction, Sy is the oscillation speed of one of the web and the nozzle surface along the second direction, and d is the diameter of the nozzle provided on the nozzle surface.

[0111] [Note 6] The above web has an elongated shape in which its longitudinal direction coincides with the first direction. The cleaning apparatus according to any one of appendices 1 to 5, further comprising a winding mechanism for winding the web in the first direction while the web and the nozzle surface are moving relative to each other by the first moving mechanism described above.

[0112] [Note 7] The nozzle surface is provided with multiple nozzles arranged in a straight line along the third direction at a first pitch interval, and positioned in multiple rows at a second pitch interval in a fourth direction perpendicular to the third direction. The first direction described above coincides with the third direction described above. The cleaning apparatus described in any one of the appendices 1 to 6, wherein the second direction described above coincides with the fourth direction described above.

[0113] [Note 8] The nozzle surface is provided with multiple nozzles arranged in a straight line along the third direction at a first pitch interval, and positioned in multiple rows at a second pitch interval in a fourth direction perpendicular to the third direction. The second direction described above coincides with the third direction described above. The cleaning apparatus described in any one of the appendices 1 to 6, wherein the first direction described above coincides with the fourth direction described above.

[0114] [Note 9] The cleaning apparatus according to any one of the appendices 1 to 8, wherein the second moving mechanism causes one of the web and the nozzle surface to oscillate while the web and the nozzle surface are moving relative to each other by the first moving mechanism.

[0115] [Note 10] The cleaning apparatus according to any one of the appendices 1 to 9, wherein the oscillation of one of the web and the nozzle surface by the second moving mechanism is a fine motion including at least one of simple harmonic motion, reciprocating motion, elliptical motion and circular motion.

[0116] [Note 11] The cleaning apparatus according to any one of the appendices 1 to 10, wherein the above-mentioned first moving mechanism moves the above-mentioned nozzle surface.

[0117] [Note 12] The cleaning device described in any one of the appendices 1 to 10, wherein the above-mentioned first moving mechanism moves the above-mentioned web.

[0118] [Note 13] The cleaning device according to any one of the appendices 1 to 12, wherein the second moving mechanism described above causes the web to swing.

[0119] [Note 14] The cleaning device according to any one of the appendices 1 to 12, wherein the second moving mechanism described above causes the nozzle surface to oscillate.

[0120] [Note 15] The cleaning device according to any one of appendices 1 to 14, wherein the above-mentioned second moving mechanism includes a piezo actuator.

[0121] [Note 16] The cleaning device according to any one of the appendices 1 to 14, wherein the above-mentioned second moving mechanism includes an electromagnetic actuator.

[0122] [Note 17] The cleaning device according to any one of appendices 1 to 14, wherein the above-mentioned second moving mechanism includes an electrostatic actuator.

[0123] [Note 18] The cleaning device according to any one of appendices 1 to 14, wherein the above-mentioned second moving mechanism includes an eccentric cam.

[0124] (Other forms, etc.) The shapes, configurations, sizes, numbers, materials, etc., of each part shown in the embodiments and modifications of the present invention described above can be modified in various ways, as long as they do not depart from the spirit of the present invention.

[0125] Furthermore, the characteristic configurations shown in the embodiments and modifications of the present invention described above can naturally be combined with each other without departing from the spirit of the present invention.

[0126] Thus, the embodiments and their variations disclosed herein are illustrative in all respects and not restrictive. The technical scope of the present invention is defined by the claims and includes all modifications within the meaning and scope equivalent to the claims. [Explanation of Symbols]

[0127] 1 Image forming apparatus, 2 Paper feeding unit, 3 Image forming unit, 4 Paper discharge unit, 5 Paper feeding tray, 6 First transport unit, 7 Second transport unit, 8 Paper discharge tray, 9 Control unit, 10 First transfer unit, 11 Transport drum, 12 Heating unit, 13 Head, 13a Nozzle surface, 14 Fixing unit, 15 Second transfer unit, 21 Nozzle unit, 22 Nozzle, 28 Ink, 30, 30A Cleaning device, 31 Web, 31a Wiping surface, 32 Supply roller, 33 Take-up roller, 34 Wiping roller, 35 Pressing member, 40 First moving mechanism, 41 Ball screw, 42 Motor, 50, 50A Second moving mechanism, 51 Biasing member, 52 Shaft member, 53 Cam member, 54 Motor, 54a Rotating shaft, 301 First thread, 301a First projection, 302 Second thread, 302a second projection, mp projection, np nip portion, P recording medium, vp valley portion.

Claims

1. A head having a nozzle surface capable of ejecting ink, A web having a wiping surface for wiping the nozzle surface, The nozzle surface and the web are moved relative to each other, The web includes a plurality of first threads extending along a first direction, and a plurality of second threads extending along a second direction intersecting the first direction and woven into the plurality of first threads. The wiping surface has a plurality of first protrusions formed by the plurality of first threads and a plurality of second protrusions formed by the plurality of second threads, The moving mechanism comprises a first moving mechanism that moves the web and the nozzle surface relative to each other along the first direction, and a second moving mechanism that swings one of the web and the nozzle surface along the second direction. A cleaning device that satisfies the condition M ≤ D, where M is the distance between adjacent first and second protrusions in the second direction among the plurality of first protrusions and the plurality of second protrusions when the wiping surface is in contact with the nozzle surface, and D is the distance by which one of the web and the nozzle surface is oscillated by the second moving mechanism when the web wipes the nozzle surface.

2. The cleaning device according to claim 1, wherein when the wiping surface is in contact with the nozzle surface, the dimension of one of the plurality of second protrusions in the second direction is N, and the condition D ≤ M + N is satisfied.

3. The cleaning apparatus according to claim 1 or 2, wherein the web is a plain weave fabric.

4. The cleaning apparatus according to claim 1, wherein the second direction is orthogonal to the first direction.

5. The cleaning apparatus according to claim 1, wherein when Wni is the dimension of the nozzle surface in the first direction of the portion that contacts the wiping surface, Sf is the relative movement speed of one of the web and the nozzle surface with respect to the other along the first direction, Sy is the oscillation speed of one of the web and the nozzle surface along the second direction, and d is the diameter of the nozzle provided on the nozzle surface, (Wni + d) / Sf ≥ 2D / Sy.

6. The web has an elongated shape in which its longitudinal direction coincides with the first direction. The cleaning apparatus according to claim 1, further comprising a winding mechanism for winding the web in a first direction while the web and the nozzle surface are moving relative to each other by the first moving mechanism.

7. The nozzle surface is provided with a plurality of nozzles arranged in a linear fashion along the third direction at a first pitch interval, and positioned in multiple rows at a second pitch interval in a fourth direction perpendicular to the third direction. The first direction coincides with the third direction. The cleaning apparatus according to claim 1, wherein the second direction coincides with the fourth direction.

8. The nozzle surface is provided with a plurality of nozzles arranged in a linear fashion along the third direction at a first pitch interval, and positioned in multiple rows at a second pitch interval in a fourth direction perpendicular to the third direction. The second direction coincides with the third direction. The cleaning apparatus according to claim 1, wherein the first direction coincides with the fourth direction.

9. The cleaning apparatus according to claim 1, wherein the second moving mechanism causes one of the web and the nozzle surface to oscillate while the web and the nozzle surface are being moved relative to each other by the first moving mechanism.

10. The cleaning apparatus according to claim 1, wherein the oscillation of one of the web and the nozzle surface by the second moving mechanism is a micro-motion including at least one of simple harmonic motion, reciprocating motion, elliptical motion and circular motion.

11. The cleaning apparatus according to claim 1, wherein the first moving mechanism moves the nozzle surface.

12. The cleaning apparatus according to claim 1, wherein the first moving mechanism moves the web.

13. The cleaning device according to claim 1, wherein the second moving mechanism causes the web to swing.

14. The cleaning apparatus according to claim 1, wherein the second moving mechanism causes the nozzle surface to oscillate.

15. The cleaning apparatus according to claim 1, wherein the second moving mechanism includes a piezo actuator.

16. The cleaning apparatus according to claim 1, wherein the second moving mechanism includes an electromagnetic actuator.

17. The cleaning apparatus according to claim 1, wherein the second moving mechanism includes an electrostatic actuator.

18. The cleaning device according to claim 1, wherein the second moving mechanism includes an eccentric cam.

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