Liquid ejection device and image forming device

Abstract

To effectively suppress damage and deterioration of a cleaning member.SOLUTION: A liquid discharge device includes a liquid discharge part 14 for discharging a liquid, and a cleaning member 41 for relatively moving while contacting the liquid discharge part 14 from one end e1 side toward the other end e2 side of the liquid discharge part 14. When the cleaning member 41 contacts the one end e1 or the other end e2 of the liquid discharge part 14, a contact force of the cleaning member 41 with the liquid discharge part 14 is smaller than that when the cleaning member 41 contacts a part other than the one end e1 and the other end e2 of the liquid discharge part 14.SELECTED DRAWING: Figure 7

Description

[Technical Field]

[0001] The present invention relates to a liquid ejection apparatus and an image forming apparatus. [Background technology]

[0002] 2. Description of the Related Art As an image forming apparatus such as a copying machine or a printer, an inkjet type image forming apparatus is known that ejects ink from a liquid ejection portion to form an image on a sheet.

[0003] In such an image forming apparatus, a cleaning member that cleans the liquid ejection unit is provided to maintain good liquid ejection function (see, for example, Patent Document 1 (JP 2019-14155 A)). Summary of the Invention [Problem to be solved by the invention]

[0004] Generally, a cleaning member moves relative to the liquid discharge portion while in contact with the liquid discharge portion to remove the liquid remaining on the liquid discharge portion by sucking or wiping it away. However, if the cleaning member comes into contact with the edge of the liquid discharge portion at this time, there is a risk that the cleaning member will be damaged or deteriorated. [Means for solving the problem]

[0005] In order to solve the above problems, the present invention provides: A liquid ejection device comprising: a liquid ejection section that ejects liquid; and a cleaning member that moves relatively while in contact with the liquid ejection section from one end side to the other end side, wherein when the cleaning member comes into contact with the one end or the other end of the liquid ejection section, the contact force of the cleaning member with respect to the liquid ejection section is smaller than when the cleaning member comes into contact with a part other than the one end and the other end of the liquid ejection section, and when the cleaning member is in contact with a part other than the one end and the other end of the liquid ejection section, the contact pressure of the cleaning member with respect to the liquid ejection section is constant, and as the contact area of ​​the cleaning member with respect to the liquid ejection section increases, the contact force of the cleaning member with respect to the liquid ejection section increases, thereby keeping the contact pressure of the cleaning member with respect to the liquid ejection section constant. It is characterized by: [Effects of the Invention]

[0006] According to the present invention, damage and deterioration of the cleaning member can be effectively suppressed. [Brief explanation of the drawings]

[0007] [Figure 1] 1 is a schematic diagram illustrating the configuration of an image forming apparatus according to an embodiment of the present invention. [Figure 2] 1 is a diagram showing a configuration of a liquid ejection apparatus according to an embodiment of the present invention; [Figure 3]FIG. 10 is a diagram for explaining a maintenance operation according to the embodiment. [Figure 4] FIG. 10 is a diagram for explaining a maintenance operation according to the embodiment. [Figure 5] FIG. 10 is a diagram for explaining a maintenance operation according to the embodiment. [Figure 6] FIG. 10 is a diagram for explaining a maintenance operation according to the embodiment. [Figure 7] 5A and 5B are diagrams illustrating the contact force and contact pressure of the suction wiper according to the first embodiment of the present invention. [Figure 8] 10A and 10B are diagrams illustrating the contact force and contact pressure of a suction wiper according to a second embodiment of the present invention. [Figure 9] 10A and 10B are diagrams illustrating the contact force and contact pressure of a suction wiper according to a third embodiment of the present invention. [Figure 10] 10A and 10B are diagrams showing the contact force and contact pressure of a suction wiper according to a fourth embodiment of the present invention. [Figure 11] 10A and 10B are diagrams showing the contact force and contact pressure of a suction wiper according to a fifth embodiment of the present invention. [Figure 12] 13 is a diagram showing the contact force and contact pressure of a suction wiper according to a sixth embodiment of the present invention. FIG. [Figure 13] 10A and 10B are diagrams illustrating an example in which the contact area of ​​the suction wiper with respect to the liquid ejection head gradually decreases. [Figure 14] 13 is a diagram showing the contact force and contact pressure of a suction wiper according to a seventh embodiment of the present invention. FIG. [Figure 15] 13 is a diagram showing the configuration of a suction wiper according to an eighth embodiment of the present invention. FIG. [Figure 16] 10A and 10B are diagrams illustrating an embodiment of a contact force changing mechanism. [Figure 17] 10A and 10B are diagrams illustrating examples of a guide portion. [Figure 18] 10A and 10B are diagrams illustrating another embodiment of a contact force changing mechanism. [Figure 19] 10A and 10B are diagrams illustrating yet another embodiment of a contact force changing mechanism. [Figure 20] FIG. 1 is a diagram illustrating an example of a serial type liquid ejection apparatus. [Figure 21]FIG. 10 is a diagram showing the configuration of another image forming apparatus to which the present invention can be applied. [Figure 22] FIG. 10 is a diagram showing the configuration of yet another image forming apparatus to which the present invention can be applied. DETAILED DESCRIPTION OF THE INVENTION

[0008] The present invention will be described below with reference to the accompanying drawings. In each drawing for explaining the present invention, components such as members and components having the same function or shape are designated by the same reference numerals as far as they can be distinguished, and descriptions thereof will be omitted once they have been described.

[0009] FIG. 1 is a schematic diagram of an image forming apparatus according to an embodiment of the present invention.

[0010] 1, an image forming apparatus 100 according to this embodiment includes a document transport device 1, an image reading device 2, an image forming unit 3, a sheet supply device 4, a cartridge mounting unit 5, a sheet discharge unit 7, and a manual sheet supply device 8. A sheet alignment device 200 is also disposed beside the image forming apparatus 100.

[0011] The document transport device 1 is a device that separates documents one by one from a document tray 11 and transports them toward a contact glass 13 of the image reading device 2. The document transport device 1 is equipped with a plurality of transport rollers and the like as a document transport means for transporting the documents.

[0012] The image reading device 2 is a device that reads an image of an original placed on the contact glass 13 or an image of an original passing over the contact glass 13. The image reading device 2 is equipped with an optical scanning unit 12 as an image reading section. The optical scanning unit 12 has a light source that irradiates light onto the original placed on the contact glass 13, and a CCD (charge coupled device) or the like as an image reading means that reads an image from the light reflected from the original. A contact image sensor (CIS) or the like may also be used as the image reading means.

[0013] The image forming unit 3 is configured by a liquid ejection device that ejects liquid ink onto a sheet to form an image. The liquid ejection device has a liquid ejection head 14 as a liquid ejection unit.

[0014] A plurality of ink cartridges 15Y, 15M, 15C, and 15Bk are removably mounted in the cartridge mounting portion 5. Each ink cartridge 15Y, 15M, 15C, and 15Bk is filled with ink of a different color, such as yellow, magenta, cyan, or black. The ink in each ink cartridge is supplied to the liquid ejection head 14 by a supply pump.

[0015] The sheet supply device 4 is equipped with a plurality of paper feed cassettes 16 as sheet storage sections. Each paper feed cassette 16 stores sheets P, so-called cut sheets, which have been cut to a predetermined size in advance in the paper transport direction (sheet transport direction), such as A4 size or B4 size, as sheets on which images are formed. Each paper feed cassette 16 is also provided with a paper feed roller 17 as sheet feeding means and a separation pad 18 as sheet separating means. When the paper feed roller 17 rotates, the topmost paper P stored in the paper feed cassette 16 is separated from the other papers (a stack of papers) by the paper feed roller 17 and the separation pad 18 and sent out.

[0016] Manual sheet feeder 8 has manual tray 51 as a loading section for loading paper, and paper feed roller 52 as a feeding means for feeding paper from manual tray 51. Manual tray 51 is attached to the image forming apparatus main body so that it can be opened and closed (swinged). When manual tray 51 is in the open state (the state shown in FIG. 1), paper can be loaded on manual tray 51 and the paper can be fed.

[0017] The sheet alignment device 200 is a post-processing device that aligns the sheets sent from the image forming device 100. In addition to the sheet alignment device 200, other post-processing devices such as a staple processing device that binds the sheets or a punch processing device that punches holes in the sheets may also be provided.

[0018] The operation of the image forming apparatus according to this embodiment will be described with reference to FIG.

[0019] When an instruction to start a printing operation is given, paper P is fed from the sheet feeder 4 or the manual sheet feeder 8. When the fed paper P is transported to the transport path 80 arranged in a position opposite the image forming unit 3, an image is formed on the paper P by the image forming unit 3. More specifically, ink is ejected from the liquid ejection head 14 onto the paper P based on the image information of the original read by the image reading device 2 or the print information instructed to be printed from the terminal, and an image is formed on the image forming surface (top surface) of the paper P. Note that the image formed on the paper P may be a meaningful image such as characters or figures, or may be a pattern that does not have any meaning in itself.

[0020] When double-sided printing is performed, the paper P is conveyed in the opposite direction downstream of the image forming unit 3 in the paper conveyance direction, thereby guiding the paper P to the reverse conveyance path 81. More specifically, after the rear end of the paper P passes through the first path switching means 71, which is arranged downstream of the image forming unit 3 in the paper conveyance direction, the first path switching means 71 switches the conveyance path to the reverse conveyance path 81, and the paper P is conveyed in the opposite direction. As a result, the paper P is guided to the reverse conveyance path 81. Then, as the paper P passes through the reverse conveyance path 81, the paper P is conveyed again to the image forming unit 3 in an inverted state, and an image is formed on the reverse side of the paper P by the same operation of the image forming unit 3 as described above.

[0021] The sheet P on which the image has been formed is selectively guided by second path switching means 72, which is located downstream of the first path switching means 71 in the sheet transport direction, to either a transport path 82 leading to the upper sheet discharge section 7 or a transport path 83 leading to the lower sheet discharge section 7. When the sheet P is guided to the transport path 82 leading to the upper sheet discharge section 7, the sheet P is discharged to the upper sheet discharge section 7. On the other hand, when the sheet P is guided to the transport path 83 leading to the lower sheet discharge section 7, the sheet P is further selectively guided by third path switching means 73 to either a transport path 84 leading to the lower sheet discharge section 7 or a transport path 85 leading to the sheet alignment device 200.

[0022] Then, when the paper P is guided to the conveying path 84 leading to the lower sheet discharge section 7, the paper P is discharged to the lower sheet discharge section 7. On the other hand, when the paper P is guided to the conveying path 85 leading to the sheet alignment device 200, the paper P is conveyed to the sheet alignment device 200, where the paper P is aligned and placed. This completes a series of printing operations.

[0023] Next, the configuration of the liquid ejection device according to this embodiment will be described with reference to FIG.

[0024] As shown in Fig. 2, the liquid ejection device (image forming unit 3) according to this embodiment has a plurality of liquid ejection heads 14 arranged side by side in the paper width direction (sheet width direction) B. The paper width direction B here refers to a direction that intersects or is perpendicular to the paper transport direction (sheet transport direction) A in which the paper P is transported. Note that the liquid ejection device according to the present invention is not limited to a configuration having a plurality of liquid ejection heads 14 as shown in Fig. 2, and may also be configured to have a single liquid ejection head arranged across the entire paper width direction B.

[0025] Each liquid ejection head 14 has a nozzle row 54 in which a plurality of nozzles are arranged. In the present embodiment, when the paper P is transported to the image forming unit 3, the ejection drive of each liquid ejection head 14 is controlled by a drive signal based on image information as the paper P passes through an area facing the image forming unit 3. This causes each liquid ejection head 14 to eject ink of each color onto the paper P, and an image according to the image information is formed on the paper P. In this way, the liquid ejection device according to this embodiment is a so-called line-type liquid ejection device in which each liquid ejection head 14 ejects ink without moving toward the paper being transported. Note that the liquid ejection device according to the present invention is not limited to a line-type liquid ejection device, and may also be a serial-type liquid ejection device, described below, in which the liquid ejection head ejects ink while moving in the main scanning direction (paper width direction).

[0026] 2, in this embodiment, the nozzle surface 55 of each liquid ejection head 14 is formed in the shape of a parallelogram. More specifically, each liquid ejection head 14 has a parallelogram-shaped nozzle surface 55 consisting of a pair of short sides 55a extending transversely to the paper width direction B and a pair of long sides 55b extending in the paper width direction B. The nozzle rows 54 of each nozzle surface 55 are arranged parallel to the long sides 55b of the nozzle surface 55. Furthermore, the ends of the nozzle rows 54 of adjacent liquid ejection heads 14 are arranged so as to overlap each other when viewed from the paper transport direction A. This allows ink to be ejected without interruption in the image between adjacent liquid ejection heads 14 in the paper width direction B.

[0027] Inkjet image forming units that form images on paper by ejecting ink from a liquid ejection head generally include a maintenance device for maintaining and restoring the functionality of the liquid ejection head. The maintenance device includes, for example, a cap member that covers the nozzle surface of the liquid ejection head, as well as a cleaning member that cleans the nozzle surface.

[0028] The maintenance operation according to this embodiment will be described below with reference to FIGS.

[0029] 3, in the image forming unit 3, the liquid ejection head 14 is configured to be switchable between a state in which it is disposed at an angle to the horizontal direction (a state shown by a solid line) and a state in which it is disposed in a horizontal direction (also referred to as a position retracted from the transport path 80) (a state shown by a two-dot chain line). When an image is formed on paper, the liquid ejection head 14 is disposed at an angle, and the liquid ejection head 14 faces the transport path 80. On the other hand, when the image forming operation is completed and a maintenance operation for the liquid ejection head 14 is performed, the liquid ejection head 14 is disposed in a horizontal direction.

[0030] When a maintenance operation is performed, a maintenance device 40 approaches the liquid ejection head 14, which has been switched to a horizontal position, as shown in FIG. 4. The maintenance device 40 is provided in the liquid ejection device, which is the image forming unit 3. The maintenance device 40 is positioned below the liquid ejection head 14 by moving in the horizontal direction (direction C, which is the paper width direction). The maintenance device 40 is equipped with a suction wiper 41 as a cleaning member that cleans the nozzle surface 55 of the liquid ejection head 14. The suction wiper 41 is a cylindrical member made of an elastic material such as rubber, and has a suction port 41a at its tip. The suction wiper 41 is provided on a carriage 42 that can move back and forth in the paper width direction B. When the carriage 42 moves along a guide rail 43, the suction wiper 41 moves together with the carriage 42 in the paper width direction C.

[0031] 5, the liquid ejection head 14 is lowered and placed in a position where the liquid ejection head 14 can be cleaned. Alternatively, the liquid ejection head 14 may not be lowered, but the maintenance device 40 may be raised and placed in a position where the liquid ejection head 14 can be cleaned. Then, in this state, as shown in FIG. 6, the suction wiper 41 moves along the guide rail 43, so that the suction wiper 41 cleans the nozzle surface 55 while coming into contact with the nozzle surface 55 of the liquid ejection head 14. More specifically, as the suction wiper 41 moves while coming into contact with the nozzle surface 55, ink remaining in the nozzles (ejection ports) is wiped away and removed, and the removed ink is sucked and collected through the suction port 41a of the suction wiper 41. This completes the cleaning operation by the suction wiper 41.

[0032] After the cleaning operation is completed, the liquid ejection head 14 is covered with a cap member to prevent ink ejection problems due to drying. When an image formation operation is to be performed again, the cap member is moved away from the liquid ejection head 14, and the maintenance device 40 is moved horizontally away from the position facing the liquid ejection head 14 to retract. The liquid ejection head 14 is then switched to an oblique position, and is ready for image formation.

[0033] The suction wiper 41 is made of an elastic material such as rubber so as not to damage the nozzle surface 55 of the liquid ejection head 14. However, if the suction wiper 41 comes into contact with an edge or corner of the liquid ejection head 14 during cleaning, the suction wiper 41 may be damaged or deteriorated by the contact. Therefore, in this embodiment, the following measures are taken to prevent damage and deterioration of the suction wiper 41.

[0034] FIG. 7 is a diagram showing the contact force and contact pressure of the suction wiper 41 according to the first embodiment of the present invention.

[0035] As shown in FIG. 7, the suction wiper 41 according to this embodiment moves in the direction of arrow C in the figure (one side of the paper width direction B), and thereby performs a cleaning operation while the contact portion 41b of the suction wiper 41 comes into contact with the nozzle surface 55 of each liquid ejection head 14 from one end e1 side toward the other end e2 side. If the contact portion 41b of the suction wiper 41 comes into contact with the ends e1 and e2 (short sides 55a) of each liquid ejection head 14 that intersect with the moving direction C, the contact portion 41b of the suction wiper 41 may be damaged or deteriorated. Note that in this specification, "one end of the liquid ejection head" (hereinafter referred to as "intersecting end") refers to the end of the liquid ejection head where a cleaning member (e.g., the suction wiper 41) begins to come into contact as it moves in contact with the liquid ejection head, and "the other end of the liquid ejection head" (hereinafter referred to as "intersecting end") refers to the end of the liquid ejection head where a cleaning member ends to come into contact as it moves in contact with the liquid ejection head.

[0036] In this embodiment, in order to prevent such damage and deterioration of the suction wiper 41, the contact force (pressure) of the suction wiper 41 with respect to each liquid ejection head 14 is made relatively small when the contact portion 41b of the suction wiper 41 passes through ends e1, e2 intersecting with the movement direction C (hereinafter referred to as "intersecting ends") of the suction wiper 41. That is, as shown in Fig. 7, in a movement range H1 when the contact portion 41b of the suction wiper 41 is in contact with the intersecting ends e1, e2 of each liquid ejection head 14, the contact force of the suction wiper 41 is made smaller than in a movement range H2 when the contact portion 41b of the suction wiper 41 is in contact with a portion of each liquid ejection head 14 other than the intersecting ends e1, e2.

[0037] In this manner, in this embodiment, when the contact portion 41b of the suction wiper 41 is in contact with the ends e1 and e2 in the intersecting direction, the contact force of the suction wiper 41 is made relatively small, thereby making it possible to relatively reduce the contact pressure of the suction wiper 41 against the liquid ejection head 14. This makes it possible to suppress damage and deterioration of the contact portion 41b of the suction wiper 41 when the contact portion 41b of the suction wiper 41 passes the ends e1 and e2 in the intersecting direction, and makes it possible to maintain the cleaning function of the suction wiper 41 for a long period of time.

[0038] 7, in this embodiment, the movement path of the suction wiper 41 is set so as to avoid the acute angles v1 and v2 among the four corners (vertices) v1 to v4 of the nozzle surface 55. In particular, when the suction wiper 41 comes into contact with the acute angles v1 and v2, such contact can accelerate damage and deterioration of the suction wiper 41. Therefore, by setting the movement path of the suction wiper 41 so as to avoid the acute angles v1 and v2 as in this embodiment, damage and deterioration of the contact portion 41b of the suction wiper 41 due to contact with the acute angles v1 and v2 can be avoided, and damage and deterioration of the suction wiper 41 can be more effectively suppressed.

[0039] FIG. 8 is a diagram showing the contact force and contact pressure of the suction wiper 41 according to the second embodiment of the present invention.

[0040] As shown in Figure 8, in this embodiment, when the contact portion 41b of the suction wiper 41 is in contact with the intersecting ends e1, e2 of each liquid ejection head 14 (within the movement range H1), the contact force and contact pressure of the suction wiper 41 are set to 0 or approximately 0.

[0041] In this way, by making the contact force and contact pressure zero or nearly zero when the contact portion 41b of the suction wiper 41 is in contact with the ends e1 and e2 in the cross direction, it is possible to more effectively prevent damage and deterioration of the contact portion 41b of the suction wiper 41. When the contact force and contact pressure of the suction wiper 41 are zero or nearly zero, the suction wiper 41 may be in contact with the liquid ejection head 14 without applying pressure, or may be separated from the liquid ejection head 14 and in a non-contact state as long as it does not affect the cleaning operation.

[0042] FIG. 9 is a diagram showing the contact force and contact pressure of the suction wiper 41 according to the third embodiment of the present invention.

[0043] As shown in Figure 9, in this embodiment, when the contact portion 41b of the suction wiper 41 is in contact with a portion other than the intersecting ends e1, e2 of each liquid ejection head 14 (within the movement range H2), the contact force of the suction wiper 41 is gradually increased so that the contact pressure of the suction wiper 41 remains constant.

[0044] 7, the basic configuration of the suction wiper 41 and the liquid ejection head 14 is the same as that of the embodiment shown in Fig. 7, and because the end e3 (long side 55b) of each liquid ejection head 14 is inclined, when the suction wiper 41 moves from one end e1 side to the other end e2 side of the liquid ejection head 14, the contact area of ​​the suction wiper 41 with the liquid ejection head 14 gradually increases. Therefore, as in the embodiment shown in Fig. 7, if the contact force (contact force in the movement range H2) after the contact portion 41b of the suction wiper 41 has passed the ends e1 and e2 in the intersecting direction is maintained without significant change, the contact area of ​​the suction wiper 41 increases as the suction wiper 41 moves, and conversely, the contact pressure of the suction wiper 41 gradually decreases.

[0045] 9, the contact force of the suction wiper 41 increases as the suction wiper 41 moves while the contact portion 41b of the suction wiper 41 is in contact with a portion of each liquid ejection head 14 other than the ends e1 and e2 in the intersecting direction (within the movement range H2). Therefore, in this embodiment, even if the contact area of ​​the suction wiper 41 gradually increases, the contact pressure of the suction wiper 41 can be maintained constant. This prevents fluctuations in the suction force or wiping action of the suction wiper 41 due to fluctuations in contact pressure, and stabilizes the cleaning function.

[0046] 7, the contact pressure of the suction wiper 41 decreases as the wiper 41 moves, so if the contact pressure is to be maintained at or above a predetermined reference value, the contact pressure must be set higher than the reference value in advance. On the other hand, in the embodiment shown in FIG. 9, the contact pressure can be maintained constant, so the contact pressure of the suction wiper 41 can be set lower overall than in the embodiment shown in FIG. 7. Therefore, in this embodiment, after the contact portion 41b of the suction wiper 41 passes the ends e1 and e2 of each liquid ejection head 14 in the intersecting direction, the contact pressure of the suction wiper 41 can be reduced while the contact portion 41b of the suction wiper 41 is in contact with the end e3 (long side 55b) of each liquid ejection head 14 extending in the movement direction C.

[0047] In this way, in this embodiment, the contact pressure while the contact portion 41b of the suction wiper 41 is in contact with the long side 55b (end e3 extending in the movement direction C) of the liquid ejection head 14 can be maintained constant and further reduced, thereby stabilizing the cleaning function and suppressing damage and deterioration of the suction wiper 41 due to contact with the long side 55b.

[0048] FIG. 10 is a diagram showing the contact force and contact pressure of the suction wiper 41 according to the fourth embodiment of the present invention.

[0049] 10, in this embodiment, the contact force and contact pressure of the suction wiper 41 with respect to each liquid ejection head 14 are gradually reduced before the contact portion 41b of the suction wiper 41 contacts the ends e1, e of each liquid ejection head 14 in the intersecting direction (within the movement range H2). In this way, in this embodiment, the contact force and contact pressure of the suction wiper 41 are gradually reduced, thereby preventing a sudden decrease in the contact force and contact pressure. This suppresses variations in the cleaning function of the suction wiper 41 that would otherwise be caused by sudden fluctuations in the contact force and contact pressure, thereby stabilizing the cleaning function.

[0050] FIG. 11 is a diagram showing the contact force and contact pressure of the suction wiper 41 according to the fifth embodiment of the present invention.

[0051] In the embodiment shown in FIG. 7 described above, the contact force (hereinafter referred to as the "first contact force") when the suction wiper 41 comes into contact with the cross-direction end e1 of the first liquid ejection head 14 from a state where it is not in contact with the liquid ejection head 14) is set to the same magnitude as the contact force (hereinafter referred to as the "second contact force") when the suction wiper 41 moves from the cross-direction end e2 of one liquid ejection head 14 (first liquid ejection unit) to the cross-direction end e1 of the other liquid ejection head 14 (second liquid ejection unit). In contrast, in the fifth embodiment shown in FIG. 11, the first contact force is set to be smaller than the second contact force. That is, in this embodiment, the contact force of the suction wiper 41 with respect to the liquid ejection head 14 is set so that the first contact force < the second contact force < the contact force with respect to portions other than the cross-direction ends e1 and e2. This more effectively prevents damage and deterioration of the suction wiper 41 and improves cleaning performance.

[0052] FIG. 12 is a diagram showing the contact force and contact pressure of the suction wiper 41 according to the sixth embodiment of the present invention.

[0053] 12, the contact force (hereinafter referred to as the "third contact force") applied when the suction wiper 41 moves from a state in which it is in contact with the end e2 of the last liquid ejection head 14 in the intersecting direction to a state in which it is not in contact with the liquid ejection head 14 is smaller than the second contact force. That is, in this embodiment, the contact force of the suction wiper 41 with respect to the liquid ejection head 14 is set so that the third contact force < the second contact force < the contact force with respect to portions other than the ends e1 and e2 in the intersecting direction. This makes it possible to more effectively prevent damage and deterioration of the suction wiper 41 and improve cleaning performance.

[0054] 7 to 12, the contact area of ​​the suction wiper 41 with the liquid ejection head 14 gradually increases as the suction wiper 41 moves from the end e1 (one end e1) of the liquid ejection head 14 in one intersecting direction to the end e2 (other end e2) in the other intersecting direction. However, the present invention is also applicable to a configuration in which the contact area of ​​the suction wiper 41 with the liquid ejection head 14 gradually decreases. Therefore, as in the example shown in FIG. 13, the liquid ejection head 14 may be disposed in a position in which the liquid ejection head 14 shown in FIG. 7 is inverted from left to right. In this case, as the suction wiper 41 moves from the end e1 of the liquid ejection head 14 in one intersecting direction to the end e2 of the liquid ejection head 14 in the other intersecting direction (in the direction of arrow C in the figure), the contact area of ​​the suction wiper 41 with the liquid ejection head 14 gradually decreases. In a liquid ejection head 14 having such a configuration, as in each of the above-mentioned embodiments, damage and deterioration of the suction wiper 41 can be suppressed by making the contact force or contact pressure of the suction wiper 41 at one end e1, e2 of the liquid ejection head 14 in the cross direction smaller than the contact force or contact pressure of the suction wiper 41 at other parts.

[0055] Next, FIG. 14 shows the configuration of a suction wiper 41 according to a seventh embodiment of the present invention.

[0056] 14, in this embodiment, the nozzle surface 55 of each liquid ejection head 14 is formed in a rectangular shape. Also, in this embodiment, the liquid ejection heads 14 are arranged so as to be offset from one another in both the paper transport direction A (a direction intersecting the movement direction C of the suction wiper 41) and the paper width direction B (the movement direction C of the suction wiper 41).

[0057] In this embodiment, a plurality of suction wipers 41 are also arranged corresponding to the liquid ejection heads 14, shifted in the paper transport direction A. That is, one suction wiper 41 is arranged corresponding to each of the liquid ejection heads 14 in the row (a) shown in the upper side of Fig. 14 and the liquid ejection heads 14 in the row (b) shown in the lower side of Fig. 14. The suction wipers 41 and liquid ejection heads 14 may be arranged in three or more rows.

[0058] In this embodiment configured as described above, the nozzle surfaces 55 of the liquid ejection heads 14 in each row are cleaned by each suction wiper 41 moving in the direction of arrow C, as in the above-described embodiment. However, even in this embodiment, if the contact portion 41b of each suction wiper 41 comes into contact with the ends e1, e2 of each liquid ejection head 14 in the intersecting direction, there is a risk that the contact portion 41b of each suction wiper 41 may be damaged or deteriorated by the contact. That is, damage and deterioration of the suction wiper 41 may occur not only when the ends e1, e2 of the liquid ejection head 14 are substantially perpendicular to the movement direction C of the suction wiper 41, as in the above-described embodiment, but also when they are perpendicular.

[0059] Therefore, in this embodiment, the contact force of each suction wiper 41 (contact force within the movement range H1) is set relatively small when the contact portion 41b of each suction wiper 41 passes the intersecting ends e1 and e2 of each liquid ejection head 14. This, as in the above-described embodiment, prevents damage and deterioration to the contact portion 41b of each suction wiper 41 when the suction wiper 41 passes the intersecting ends e1 and e2, thereby maintaining the cleaning function of each suction wiper 41 for a long period of time. Furthermore, in this embodiment, the contact area of ​​the suction wiper 41 with the liquid ejection head 14 remains constant as the suction wiper 41 moves from one intersecting end e1 of the liquid ejection head 14 to the other intersecting end e2. Therefore, if the contact force of the suction wiper 41 with the liquid ejection head 14 is kept constant, the contact pressure of the suction wiper 41 can also be maintained constant, preventing fluctuations in the suction force or wiping action of the suction wiper 41. This also stabilizes the cleaning function. The contact pressure of the suction wiper 41 against the liquid ejection head 14 does not necessarily have to be kept constant, but may be varied.

[0060] 7 to 10 may be used to control the specific contact pressure of each suction wiper 41. However, in this embodiment, since the timing at which each suction wiper 41 reaches the liquid ejection head 14 is different, the timing at which the contact force of each suction wiper 41 is controlled must be different. That is, in this embodiment, as shown in the timing charts of contact force shown in (a) and (b) in FIG. 14, the contact force is first reduced when the contact portion 41b of the suction wiper 41 in the (b) row reaches the end e1 of the corresponding liquid ejection head 14 in the intersecting direction, and then the contact force is reduced when the contact portion 41b of the suction wiper 41 in the (a) row reaches the end e1 of the corresponding liquid ejection head 14 in the intersecting direction. In this way, in this embodiment, the contact force of each suction wiper 41 is independently controlled at different times, thereby preventing damage and deterioration of the contact portion 41b of each suction wiper 41.

[0061] 15, the relative positions (movement start positions) of the suction wipers 41 with respect to the liquid ejection heads 14 may be set to be the same, so that the timing at which the contact portions 41b of the suction wipers 41 reach the corresponding liquid ejection heads 14 is the same. In this case, the contact forces of the suction wipers 41 that contact the liquid ejection heads 14 can be controlled synchronously in the (a) and (b) rows.

[0062] Next, a contact force changing mechanism that changes the contact force of the suction wiper 41 with respect to the liquid ejection head 14 will be described.

[0063] FIG. 16 is a diagram showing an embodiment of a contact force changing mechanism.

[0064] The contact force change mechanism 50 shown in FIG. 16 includes a holding member 44 that holds the suction wiper 41, a spring 45 as an elastic member that presses the suction wiper 41, a support member 46 that supports the spring 45, and a guide member 47 that guides the support member 46 in the movement direction C of the suction wiper 41. The holding member 44 holds the suction wiper 41 so that it can move toward and away from the liquid ejection head 14. The suction wiper 41 is held by the holding member 44 so that at least the suction port 41a at its tip protrudes outward (toward the liquid ejection head 14). The end of the spring 45 opposite the suction wiper 41 side is supported by the support member 46, and the spring 45 is interposed between the suction wiper 41 and the support member 46. Because the spring 45 is interposed between the suction wiper 41 and the support member 46 in a compressed state, the suction wiper 41 is pressed toward the liquid ejection head 14. The support member 46 has a plurality of protrusions 46a that come into contact with the guide member 47. In this embodiment, the support member 46 comes into contact with the guide member 47 via the plurality of protrusions 46a in order to stabilize the posture of the suction wiper 41. That is, the support member 46 stabilizes the posture of the suction wiper 41 by coming into contact with the guide member 47 at a plurality of points that are not on the same line.

[0065] In the contact force change mechanism 50 configured as described above, when the suction wiper 41 moves to perform a cleaning operation, the support member 46 is guided along the guide portion 47a of the guide member 47. As a result, the end of the spring 45 opposite the suction wiper 41 side (the end on the support member 46 side) approaches or moves away from the liquid ejection head 14, changing the amount of compression of the spring 45. That is, when the support member 46 approaches the liquid ejection head 14 as guided by the guide portion 47a (the state on the left side in FIG. 16), the amount of compression of the spring 45 increases. Conversely, when the support member 46 moves away from the liquid ejection head 14 as guided by the guide portion 47a (the state on the right side in FIG. 16), the amount of compression of the spring 45 decreases. As a result, the contact force of the suction wiper 41 with respect to the liquid ejection head 14 changes. 17(a) to 17(d), the guide portion 47a may be shaped to conform to any of the contact force changes shown in FIGS. 7 to 10, thereby reducing the contact force of the suction wiper 41 at the ends e1 and e2 in the cross direction, thereby preventing damage and deterioration of the suction wiper 41.

[0066] FIG. 18 shows another embodiment of the contact force changing mechanism.

[0067] 18 does not move the suction wiper 41 closer to or farther from the liquid ejection head 14, but rather moves the liquid ejection head 14 closer to or farther from the suction wiper 41, thereby changing the contact force of the suction wiper 41 with respect to the liquid ejection head 14. Specifically, the contact force change mechanism 50 according to this embodiment includes a contact / separation drive device 48 that moves the liquid ejection head 14 closer to or farther from the suction wiper 41, a position detection device 49 that detects the relative movement position of the suction wiper 41 with respect to the liquid ejection head 14, and a control unit 53 that controls the contact / separation drive device 48 based on the detection signal of the position detection device 49.

[0068] The position detection device 49 is composed of an encoder 56 with a black and white print pattern arranged in a stripe shape, and an optical sensor 57 with a light-emitting section and a light-receiving section. The sensor 57 is provided so as to be movable together with the suction wiper 41. As the suction wiper 41 moves, light is emitted from the light-emitting section of the sensor 57 toward the encoder 56, and the light reflected by the encoder 56 is received by the light-receiving section of the sensor 57. The control unit 53 counts the pulse signals generated at this time, thereby detecting the relative movement position of the suction wiper 41. The control unit 53 also controls the drive of the contact / separation drive device 48 based on the detected relative movement position of the suction wiper 41. This allows the contact force of the suction wiper 41 to be reduced when the suction wiper 41 passes the ends e1 and e2 of each liquid ejection head 14 in the intersecting direction.

[0069] FIG. 19 is a diagram showing yet another embodiment of the contact force changing mechanism.

[0070] 19, the control unit 53 controls the contact / separation drive device 48, which moves the suction wiper 41 toward or away from the liquid ejection head 14, based on a detection signal from a sensor 58 (position detection device 49). The sensor 58 may be an optical sensor or a magnetic sensor. Alternatively, instead of the sensor 58, a timer may be used to measure the movement time of the suction wiper 41, and the movement position of the suction wiper 41 may be controlled based on the measured movement time of the suction wiper 41. The contact force change mechanism 50 may also be a mechanism that moves both the suction wiper 41 toward or away from the liquid ejection head 14.

[0071] Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and various modifications are possible without departing from the spirit and scope of the invention.

[0072] For example, the present invention can also be applied to a serial type liquid ejection apparatus as shown in FIG.

[0073] The serial type liquid ejection device (image forming unit 3) shown in Figure 20 includes a carriage 9 carrying a liquid ejection head 14, a guide member (guide rod) 10 for guiding the carriage 9 in the main scanning direction, which is the paper width direction B, and a drive device 19 for moving the carriage 9.

[0074] In this embodiment, the carriage 9 is provided with a black liquid ejection head 14A having an ejection port array for ejecting black ink droplets, and a color liquid ejection head 14B having an ejection port array for ejecting cyan, magenta, and yellow inks. Each liquid ejection head 14A, 14B is mounted with the ink ejection direction facing downward so that each ejection port array is arranged in a direction intersecting the main scanning direction (paper transport direction A). Separate liquid ejection heads may be provided for each different color. The liquid ejection heads may also be heads for ejecting black and cyan inks, and heads for ejecting magenta and yellow inks. The ink colors used are not limited to those described above.

[0075] The energy generating means for ejecting ink provided in each liquid ejection head 14A, 14B can be a piezoelectric actuator such as a piezoelectric element, a thermal actuator that uses film boiling of liquid using an electrothermal conversion element such as a heating resistor, a shape memory alloy actuator that uses a metal phase change due to temperature change, an electrostatic actuator that uses electrostatic force, etc. Also, the carriage 9 is equipped with a plurality of sub-tanks for supplying ink of each color to each liquid ejection head 14A, 14B, and each sub-tank is replenished with ink from ink cartridges 15Y, 15M, 15C, 15Bk (see FIG. 1) mounted on the image forming apparatus main body via an ink supply tube.

[0076] The drive device 19 includes a motor 28 as a drive source, and a timing belt 35 wound around a drive pulley 29 and a driven pulley 30. When the motor 28 is driven and the drive pulley 29 rotates, the timing belt 35 moves in an orbit, causing the carriage 9 connected to the timing belt 35 to move in the main scanning direction (paper width direction B) along the guide member 10. In addition, by switching the rotation direction of the motor 28 between one direction and the opposite direction, the carriage 9 can move back and forth in the main scanning direction.

[0077] When paper is transported to the image forming unit 3, ink is ejected from each of the liquid ejection heads 14A, 14B in accordance with an image signal while the carriage 9 moves in the main scanning direction, thereby forming an image for one line on the stationary paper P. Then, after the paper P is transported a predetermined distance in the direction of arrow A in Figure 20, the next line of image is formed. In the same manner, the paper P is transported and stopped, and the carriage 9 moves back and forth repeatedly, and ink is ejected onto the paper P to form an image.

[0078] The serial liquid ejection device according to this embodiment also includes a maintenance device 40 that performs maintenance on the liquid ejection heads 14A and 14B. The maintenance device 40 includes cap members 36A and 36B that cover the liquid ejection heads 14A and 14B, a blade wiper 37 that is a blade-shaped cleaning member, and a suction wiper 41 that has the same function as in the above-described embodiment.

[0079] When a maintenance operation is performed, each of the liquid ejection heads 14A, 14B moves in the main scanning direction (paper width direction B), bringing each of the liquid ejection heads 14A, 14B closer to the maintenance device 40. Then, each of the liquid ejection heads 14A, 14B moves further in the main scanning direction, causing the blade wiper 37 and the suction wiper 41 to move relatively while contacting each of the liquid ejection heads 14A, 14B, thereby removing ink and the like adhering to the nozzles of each of the liquid ejection heads 14A, 14B.

[0080] However, even in such a serial-type liquid ejection device, if the suction wiper 41 comes into contact with the edges of the liquid ejection heads 14A, 14B in the intersecting direction during cleaning, the suction wiper 41 may be damaged or deteriorated. Therefore, it is preferable to apply the present invention to a serial-type liquid ejection device as well. By applying the present invention to a serial-type liquid ejection device, damage and deterioration of the suction wiper 41 due to contact with the edges in the intersecting direction can be suppressed, and the cleaning function of the suction wiper 41 can be maintained for a long period of time.

[0081] Furthermore, the problem of damage and deterioration of cleaning members is not limited to the suction wiper 41. That is, even in the blade wiper 37 shown in Fig. 20, if the blade wiper 37 comes into contact with the ends of the liquid ejection heads 14A, 14B in the intersecting direction as the blade wiper 37 moves relative to the liquid ejection heads 14A, 14B, there is a risk of damage and deterioration of the blade wiper 37. Therefore, even in such a blade wiper 37, damage and deterioration of the blade wiper 37 can be suppressed by reducing the contact force and contact pressure when the blade wiper 37 comes into contact with the ends in the intersecting direction.

[0082] Furthermore, the present invention is not limited to the image forming apparatus shown in FIG. 1, but can also be applied to an image forming apparatus shown in FIG. 21 or FIG.

[0083] The following describes the configuration of other image forming apparatuses to which the present invention can be applied. Note that in each image forming apparatus, the description will be focused on the parts that are different from the above-described embodiment, and the other parts are the same as the above-described embodiment, so the description will be omitted.

[0084] First, the image forming apparatus 100 shown in Fig. 21 includes, similarly to the above-described embodiment, an original transport device 1, an image reading device 2, an image forming unit 3, a sheet supply device 4, a cartridge mounting unit 5, and a sheet discharge unit 7. However, the image forming apparatus 100 shown in Fig. 21 does not include a manual sheet supply device 8. Also, unlike the embodiment shown in Fig. 1, the image forming unit 3 is disposed so as to face a transport path 20 along which paper P is transported horizontally.

[0085] 21, when a printing operation is started, a sheet P is supplied from the sheet supply device 4 and conveyed to the image forming unit 3. Then, when the sheet P is conveyed to the image forming unit 3, ink is ejected from the liquid ejection head 14 onto the sheet P to form an image.

[0086] When double-sided printing is performed, after the paper P passes through the image forming unit 3, the paper P is transported in the opposite direction, and the first path switching means 31 guides the paper P to the reversing transport path 21. By passing through the reversing transport path 21, the paper P is transported again to the image forming unit 3 in an inverted state, and an image is formed on the back side of the paper P.

[0087] The paper sheet P, on which an image has been formed on one or both sides, is selectively guided by the second path switching means 32 to either the conveying path 23 leading to the sheet discharge section 7 or the conveying path 22 leading to the sheet alignment device 200. When the paper sheet P is guided to the conveying path 23 leading to the sheet discharge section 7, the paper sheet P is discharged to the sheet discharge section 7. On the other hand, when the paper sheet P is guided to the conveying path 22 leading to the sheet alignment device 200, the paper sheet P is conveyed to the sheet alignment device 200, where the paper sheet P is aligned and placed.

[0088] 22, like the image forming apparatus 100 shown in FIG. 1, includes a document transport device 1, an image reading device 2, an image forming unit 3, a sheet supply device 4, a cartridge mounting unit 5, a sheet discharge unit 7, and a manual sheet supply device 8. In this case, like the embodiment shown in FIG. 21, the image forming unit 3 is disposed to face a transport path 86 along which paper P is transported horizontally.

[0089] 22, when a printing operation is started, paper P is supplied from the sheet supply device 4 or the manual sheet supply device 8, and the paper P is transported to the image forming unit 3. Then, when the paper P is transported to the image forming unit 3, ink is ejected from the liquid ejection head 14 onto the paper P, and an image is formed.

[0090] When double-sided printing is performed, after the paper P passes through the image forming unit 3, the paper P is transported in the opposite direction, and the first path switching means 74 guides the paper P to the reverse transport path 87. By passing through the reverse transport path 87, the paper P is transported again to the image forming unit 3 in an inverted state, and an image is formed on the back side of the paper P.

[0091] The paper sheet P having an image formed on one or both sides is selectively guided by the second path switching means 75 to either a conveying path 88 leading to the sheet discharge section 7 or a conveying path 89 leading to the sheet alignment device 200. When the paper sheet P is guided to the conveying path 88 leading to the sheet discharge section 7, the paper sheet P is discharged to the sheet discharge section 7. On the other hand, when the paper sheet P is guided to the conveying path 89 leading to the sheet alignment device 200, the paper sheet P is conveyed to the sheet alignment device 200, where the paper sheet P is aligned and placed.

[0092] 21 or 22, the same effects as those described above can be obtained by applying the present invention to the image forming apparatus 100. That is, damage and deterioration of the cleaning member that cleans the liquid ejection head 14 can be suppressed, and the cleaning function can be maintained for a long period of time.

[0093] Furthermore, the present invention is not limited to applications in inkjet image forming apparatuses that form images by ejecting ink onto a sheet. The liquid ejection apparatus according to the present invention is not limited to an apparatus that ejects liquid onto an object onto which the liquid can adhere, but may also be an apparatus that ejects liquid into air or liquid. Examples of liquid ejection apparatuses include, for example, image forming apparatuses that eject ink to form an image on paper, as well as three-dimensional modeling apparatuses (three-dimensional modeling apparatuses) that eject modeling liquid onto a powder layer formed by layering powder in order to form a three-dimensional object (a three-dimensional model).

[0094] The liquid ejection device according to the present invention may also include means for feeding, transporting, and discharging objects onto which liquid can be attached, as well as pre-processing devices and post-processing devices. "Objects onto which liquid can be attached" refers to objects onto which liquid can be attached at least temporarily, such as those onto which liquid can adhere and stick, or those onto which liquid can penetrate. Specific examples include recording media such as paper, resin film, and cloth, electronic circuit boards, electronic components such as piezoelectric elements, powder layers, organ models, and test cells. Unless otherwise specified, the term "objects onto which liquid can be attached" includes all objects onto which liquid can be attached, such as paper, thread, fiber, fabric, leather, metal, plastic, glass, wood, ceramics, building materials such as wallpaper and flooring, and textiles for clothing, as long as the liquid can be attached even temporarily. Examples of liquids include ink, processing liquid, DNA samples, resists, patterning materials, binders, modeling liquids, and solutions and dispersions containing amino acids, proteins, and calcium.

[0095] Furthermore, the liquid ejection device according to the present invention may also be a treatment liquid application device that ejects a treatment liquid onto paper in order to apply the treatment liquid to the surface of the paper for purposes such as modifying the surface of the paper, or an injection granulation device that sprays a composition liquid in which raw materials are dispersed through a nozzle to granulate fine particles of the raw materials. [Explanation of symbols]

[0096] 3 Image forming section (liquid ejection device) 14 Liquid ejection head (liquid ejection unit) 41 Suction wiper (cleaning member) 45 Spring (elastic member) 47 Guide member 48 Approach and separation drive device 49 Position detection device 50 Contact force change mechanism [Prior art documents] [Patent documents]

[0097] [Patent Document 1] Japanese Patent Application Publication No. 2019-14155

Claims

1. A liquid ejection unit that ejects liquid; a cleaning member that moves relatively to the liquid discharger while contacting the liquid discharger from one end side to the other end side of the liquid discharger; A liquid ejection device comprising: when the cleaning member comes into contact with the one end or the other end of the liquid discharge portion, the contact force of the cleaning member with the liquid discharge portion is smaller than when the cleaning member comes into contact with a portion other than the one end or the other end of the liquid discharge portion, when the cleaning member is in contact with a portion of the liquid discharge portion other than the one end and the other end, a contact pressure of the cleaning member with respect to the liquid discharge portion is constant, A liquid ejection device characterized in that the contact force of the cleaning member against the liquid ejection portion increases as the contact area of ​​the cleaning member against the liquid ejection portion increases, and the contact pressure of the cleaning member against the liquid ejection portion is kept constant.

2. A liquid ejection unit that ejects liquid; a cleaning member that moves relatively to the liquid discharger while contacting the liquid discharger from one end side to the other end side of the liquid discharger; A liquid ejection device comprising: when the cleaning member comes into contact with the one end or the other end of the liquid discharge portion, the contact force of the cleaning member with the liquid discharge portion is smaller than when the cleaning member comes into contact with a portion other than the one end or the other end of the liquid discharge portion, A liquid ejection device, characterized in that the contact force of the cleaning member with the liquid ejection portion gradually decreases before the cleaning member comes into contact with the one end or the other end of the liquid ejection portion.

3. The liquid discharge unit and the cleaning member are arranged in a plurality of positions offset in a direction intersecting the direction of relative movement of the cleaning member, 3. The liquid ejection device according to claim 1, wherein the contact force of the cleaning member with respect to the liquid ejection unit is controlled independently for each liquid ejection unit or for each cleaning member.

4. The liquid discharge unit and the cleaning member are arranged in a plurality of positions offset in a direction intersecting the direction of relative movement of the cleaning member, 3. The liquid ejection device according to claim 1, wherein the contact force of the cleaning member against the liquid ejection unit is controlled synchronously for a plurality of the liquid ejection units and a plurality of the cleaning members.

5. A contact force changing mechanism is provided to change the contact force of the cleaning member with respect to the liquid discharge portion, The liquid ejection device according to claim 1 , wherein the contact force change mechanism changes the contact force of the cleaning member with the liquid ejection unit by moving the cleaning member closer to or farther away from the liquid ejection unit.

6. A contact force changing mechanism is provided to change the contact force of the cleaning member with respect to the liquid discharge portion, The liquid ejection device according to claim 1 , wherein the contact force change mechanism changes the contact force of the cleaning member with respect to the liquid ejection unit by moving the liquid ejection unit closer to or farther away from the cleaning member.

7. A contact force changing mechanism is provided to change the contact force of the cleaning member with respect to the liquid discharge portion, 5. A liquid ejection device as described in any one of claims 1 to 4, wherein the contact force change mechanism includes an elastic member that presses the cleaning member toward the liquid ejection portion, and a guide member that guides the end of the elastic member opposite the cleaning member in a direction toward or away from the liquid ejection portion as the cleaning member moves relative to the liquid ejection portion from one end side to the other end side.

8. A liquid ejection unit that ejects liquid; a cleaning member that moves relatively to the liquid discharger while contacting the liquid discharger from one end side to the other end side of the liquid discharger; A liquid ejection device comprising: when the cleaning member comes into contact with the one end or the other end of the liquid discharge portion, the contact force of the cleaning member with the liquid discharge portion is smaller than when the cleaning member comes into contact with a portion other than the one end or the other end of the liquid discharge portion, a contact force changing mechanism for changing the contact force of the cleaning member with respect to the liquid discharge unit, a position detection device that detects the relative movement position of the cleaning member from one end side to the other end side of the liquid ejection unit, and a contact / separation drive device that moves the cleaning member closer to or away from the liquid ejection unit based on the relative movement position of the cleaning member detected by the position detection device.

9. An image forming apparatus comprising a liquid ejection device according to any one of claims 1 to 8.

Images