Head unit and inkjet recording device

Abstract

To provide a head unit and an inkjet recording device which have cap mechanisms and compact structures.SOLUTION: A head unit includes: a recording head which has a nozzle surface where a plurality of nozzles are arranged, and is movable between a first position and a second position; a cap which is provided on the recording head, and is movable between a third position covering the nozzle surface and a fourth position opening the nozzle surface; and an interlock mechanism which moves the cap from the third position to the fourth position by moving operation from the first position to the second position of the recording head, and moves the cap from the fourth position to the third position by moving operation from the second position to the first position of the recording head.SELECTED DRAWING: Figure 10

Description

Technical Field

[0001] The present invention relates to a head unit and an inkjet recording apparatus, and more particularly to a head unit and an inkjet recording apparatus provided with a cap mechanism.

Background Art

[0002] In an inkjet recording apparatus, typical malfunctions of a recording head that cause image quality defects are non-ejection and changes in the ejection state (such as defective ejection direction, changes in ejection amount, and changes in ejection speed). When non-ejection or a change in the ejection state occurs in a specific nozzle, streaks appear in the recorded image.

[0003] The main factors causing malfunctions in the recording head are adhesion of foreign substances to the nozzle surface, solidification of ink, thickening, etc. As one of the means to suppress these, a cap mechanism is known. The cap mechanism suppresses solvent evaporation from the nozzles and adhesion of foreign substances to the nozzle surface by covering the nozzle surface with a cap when not in use.

[0004] Generally, the cap mechanism is provided in a maintenance area separate from the position where the image recording operation is performed. Therefore, when capping, it is necessary to move the recording head to the maintenance area.

[0005] Patent Documents 1 and 2 describe techniques that eliminate the need to move to a maintenance position by providing a cap mechanism on the recording head.

Prior Art Documents

Patent Documents

[0006]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0007] However, the techniques described in Patent Documents 1 and 2 have drawbacks in that power is required to open and close the cap and the recording head becomes large in size.

[0008] The present invention has been made in view of such circumstances, and an object thereof is to provide a head unit and an inkjet recording apparatus having a compact configuration including a cap mechanism.

Means for Solving the Problems

[0009] (1) A recording head having a nozzle surface on which a plurality of nozzles are arranged and movable between a first position and a second position, a cap provided on the recording head and movable between a third position covering the nozzle surface and a fourth position opening the nozzle surface, and an interlocking mechanism that moves the cap from the third position to the fourth position by an operation of the recording head moving from the first position to the second position and moves the cap from the fourth position to the third position by an operation of the recording head moving from the second position to the first position.

[0010] (2) The recording head moves between the first position and the second position by linear motion, the cap moves between the third position and the fourth position by arc motion, and the interlocking mechanism converts the linear motion of the recording head into arc motion of the cap. The head unit according to (1).

[0011] (3) The interlocking mechanism includes a biasing member that biases the cap toward the fourth position, and an engaging member that engages with the cap at a fixed position with respect to the recording head moving from the second position to the first position and moves the cap from the fourth position to the third position against the biasing force of the biasing member. The head unit according to (2).

[0012] (4) The interlocking mechanism includes a biasing member that biases the cap toward the third position, and an engaging member that engages with the cap at a fixed position with respect to the recording head moving from the first position to the second position and moves the cap from the third position to the fourth position against the biasing force of the biasing member. The head unit according to (2).

[0013] (5) The interlocking mechanism is composed of a gear combination including a rack and a pinion, and is the head unit according to (2).

[0014] (6) The interlocking mechanism is composed of a cam mechanism or a link mechanism that converts linear motion into arc motion, and is the head unit according to (2).

[0015] (7) The cap has an open hollow shape, and in the third position, the opening is arranged to face the nozzle surface, and is the head unit according to any one of (1) to (6).

[0016] (8) The head unit according to (7), further comprising a sealing member provided on the recording head or the cap and sealing the periphery of the opening between the cap located in the third position and the recording head.

[0017] (9) The head unit according to (8), further comprising a locking mechanism for locking the cap located in the third position.

[0018] (10) The head unit according to (9), wherein the locking mechanism is composed of a push-latch mechanism.

[0019] (11) The cap has a liquid absorbent inside, and is the head unit according to any one of (7) to (10).

[0020] (12) The cap has a weir portion that blocks the liquid stored inside from flowing out of the opening when tilted, and is the head unit according to any one of (7) to (11).

[0021] (13) The cap is divided into two parts in the depth direction by the weir portion, a liquid for moisturizing is stored in the space on the bottom side across the weir portion, and the liquid discharged or ejected from the nozzle is recovered in the space on the opening side across the weir portion, and is the head unit according to (12).

[0022] (14) The cap moves between a third position and a fourth position by an arc motion centered on an axis parallel to the array direction of the nozzles, and in a cross-section orthogonal to the axis, the part of the cap closest to the axis is the edge of the cap, the head unit according to any one of (1) to (13).

[0023] (15) The head unit according to any one of (1) to (14), further comprising a drive unit that moves the recording head between a first position and a second position.

[0024] (16) An inkjet recording apparatus comprising a conveyance unit that conveys a medium, and the head unit according to any one of (1) to (15) that discharges ink from nozzles toward the medium conveyed by the conveyance unit and records an image on the medium.

[0025] (17) The inkjet recording apparatus according to (16), wherein the head unit records an image on the medium in a single pass.

Advantages of the Invention

[0026] According to the present invention, it is possible to provide a head unit and an inkjet recording apparatus having a compact configuration provided with a cap mechanism.

Brief Description of the Drawings

[0027]

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Embodiments for Carrying Out the Invention

[0028] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

[0029] [First Embodiment] Here, a case where the present invention is applied to an inkjet printer that prints a desired image on a single sheet of paper in a single pass will be described as an example. The inkjet printer is an example of an inkjet recording apparatus.

[0030] [Inkjet Printer] FIG. 1 is a side view showing a schematic configuration of the inkjet printer. FIG. 2 is a plan view showing a schematic configuration of the inkjet printer.

[0031] As shown in FIGS. 1 and 2, the inkjet printer 1 of the present embodiment includes a paper conveyance unit 10 that conveys the paper P, a printing unit 20 that prints an image on the paper P, and an image reading unit 30 that reads the image printed on the paper P. The paper P is composed of a single sheet of paper. The paper P is an example of a medium.

[0032] [Paper Conveyance Unit] The paper conveyance unit 10 conveys the paper P along a specified path. As an example, in the present embodiment, the paper P is conveyed by a belt. That is, the paper P is adsorbed on the surface of the running belt 11 and conveyed.

[0033] The belt 11 is composed of an endless belt. The belt 11 is wound around a plurality of rollers 12 including a driving roller 12A, and a running path is set. A belt driving motor 13 is connected to the driving roller 12A as a driving source. By rotating the driving roller 12A by the belt driving motor 13, the belt 11 runs along the path. In the present embodiment, the section where the belt 11 runs horizontally is used to convey the paper P. Therefore, the paper P is conveyed horizontally (in FIG. 1, it is conveyed horizontally from the right side to the left side of the paper surface).

[0034] The sheet P is adsorbed on the surface of the belt 11 and conveyed. The method of adsorbing the sheet P to the belt 11 is not particularly limited. As an example, in the present embodiment, air pressure (negative pressure) is used to adsorb the sheet P to the belt 11. In this case, a suction unit 15 is provided inside the belt 11, and the belt 11 is provided with suction holes. By suction from the inside of the belt 11 by the suction unit 15, the sheet P is adsorbed to the surface of the belt 11 through the suction holes. In addition, a method using static electricity (so-called electrostatic adsorption) or the like can also be adopted for the adsorption of the sheet P.

[0035] Note that the sheet P is supplied from a paper feeding unit (not shown) to the paper conveying unit 10. The sheet P is subjected to pre-treatment as necessary. For example, a predetermined treatment liquid is applied to the surface. When pre-treatment is performed, a pre-treatment unit is provided upstream of the printing unit 20.

[0036] The printed sheet P is discharged to a paper discharging unit (not shown). The printed sheet P is subjected to post-treatment before discharging as necessary. For example, coating treatment such as varnish, drying treatment, etc. are performed. When post-treatment is performed, a post-treatment unit is provided downstream of the image reading unit 30.

[0037] [Printing Unit] The printing unit 20 prints a color image on the sheet P conveyed by the paper conveying unit 10 in a single pass. As an example, in the present embodiment, a color image is printed on the sheet P using four colors of ink: cyan (C), magenta (M), yellow (Y), and black (Bk).

[0038] The printing unit 20 includes the same number of print head units as the number of ink colors used. In the present embodiment, since four colors of ink are used, four print head units are provided. Specifically, it includes a cyan (C) print head unit 100C, a magenta (M) print head unit 100M, a yellow (Y) print head unit 100Y, and a black (Bk) print head unit 100Bk.

[0039] Each print head unit 100C, 100M, 100Y, and 100Bk has a print head 200C, 200M, 200Y, and 200Bk respectively, and ejects ink droplets of the corresponding color from the print heads 200C, 200M, 200Y, and 200Bk. Specifically, the cyan print head unit 100C ejects cyan ink droplets from the print head 200C. The magenta print head unit 100M ejects magenta ink droplets from the print head 200M. The yellow print head unit 100Y ejects yellow ink droplets from the print head 200Y. The black print head unit 100Bk ejects black ink droplets from the print head 200Bk. The configuration of the print head unit will be described later.

[0040] Each print head unit 100C, 100M, 100Y, and 100Bk is arranged at regular intervals on the conveyance path of the paper P. In the present embodiment, they are arranged at regular intervals in the horizontal direction with respect to the horizontally conveyed paper P. Each print head unit 100C, 100M, 100Y, and 100Bk is assembled to a frame (the frame of the inkjet printer 1) not shown and installed at a predetermined position.

[0041] As the paper P passes through each print head unit 100C, 100M, 100Y, and 100Bk, ink droplets of each color are applied to the surface, and a color image is printed on the surface.

[0042] [Image reading unit] The image reading unit 30 reads the image printed on the paper P. The image reading unit 30 is provided with an image reading device 31. The image reading device 31 is composed of a line scanner and reads an image from the paper P horizontally conveyed by the paper conveyance unit 10.

[0043] [Print head unit] As described above, the printing unit 20 of the inkjet printer 1 according to the present embodiment is provided with four print head units 100C, 100M, 100Y, and 100Bk. Each of the print head units 100C, 100M, 100Y, and 100Bk has the same configuration, differing only in the type (color) of ink ejected from the print heads 200C, 200M, 200Y, and 200Bk. Here, the configuration of the common print head unit 100 will be described. In the present embodiment, the print head unit 100 is an example of a head unit.

[0044] FIG. 3 is a front view of the print head unit. FIG. 4 is a side view of the print head unit.

[0045] As shown in FIGS. 3 and 4, the print head unit 100 includes a base frame 110, a print head 200, a print head lifting mechanism 300, a cap 400, and a cap opening / closing mechanism 500. The cap 400 and the cap opening / closing mechanism 500 constitute a cap mechanism for the print head 200.

[0046] [Base Frame] The base frame 110 is a frame that serves as the base of the print head unit 100. The print head 200, the print head lifting mechanism 300, the cap 400, and the cap opening / closing mechanism 500 are assembled to and integrated with the base frame 110.

[0047] The base frame 110 has a top surface portion 110T and side wall portions 110L and 110R that extend vertically from both ends of the top surface portion 110T, and has an inverted U-shaped or portal-shaped configuration in a front view as shown in FIG. 3.

[0048] [Print Head] The print head 200 is a so-called line head and has a configuration that enables printing a desired image in a single pass. Therefore, it has a printing width (printing width) that covers the paper width. As an example, the print head 200 of the present embodiment has an overall flat rectangular parallelepiped shape and has a nozzle surface (head face surface) 210 at its tip portion (lower end portion in FIGS. 3 and 4). The nozzle surface 210 is the surface on which the nozzles are arranged.

[0049] FIG. 5 is a diagram showing a schematic configuration of the nozzle surface. FIG. 6 is an enlarged view of a part of the nozzle surface. FIGS. 5 and 6 show an example in the case where the print head 200 is configured by connecting a plurality of head modules 201. Since this type of configuration is well-known, details thereof will be omitted.

[0050] In FIGS. 5 and 6, the Y direction is the conveyance direction of the paper P, and the X direction is the direction orthogonal to the conveyance direction of the paper P (the width direction of the paper P). The conveyance direction of the paper P is defined as the front-rear direction of the print head 200, with the upstream side in the conveyance direction being the front side (front face side) and the downstream side being the rear side (back face side).

[0051] As shown in FIG. 5, the print head 200 of the present embodiment has a rectangular nozzle surface 210. The nozzle surface 210 is composed of a flat surface (including a range recognized as substantially flat). A strip-shaped nozzle region 211 is provided at the central portion of the nozzle surface 210. The nozzle region 211 is the region where a plurality of nozzles 212 are arranged. In the present embodiment, it is set with a constant width (including a range recognized as substantially constant) along the width direction (X direction) of the paper P.

[0052] A plurality of nozzles 212 are arranged in the nozzle region 211 so as to achieve a desired resolution. As an example, in the present embodiment, as shown in FIG. 6, the nozzles 212 are arranged in a matrix to achieve a desired resolution (for example, 1200 dpi).

[0053] In FIGS. 5 and 6, the X direction (the longitudinal direction of the nozzle surface 210) is the arrangement direction of the substantially nozzles 212. The print head 200 assembled to the base frame 110 is arranged such that the tip nozzle surface 210 faces the paper P conveyed by the paper conveyance unit 10. Further, the arrangement direction of the nozzles 212 is arranged orthogonal to the conveyance direction of the paper P. As described above, in the present embodiment, since the paper P is conveyed horizontally, the print head 200 has the nozzle surface 210 arranged horizontally. In the present embodiment, the print head 200 is an example of a recording head.

[0054] [Print head lifting mechanism] The print head lifting mechanism 300 moves the print head 200 forward and backward with respect to the paper P conveyed by the paper conveyance unit 10. In the present embodiment, since the paper P is conveyed horizontally, the print head lifting mechanism 300 is configured as a mechanism for lifting (moving up and down) the print head 200.

[0055] The print head lifting mechanism 300 includes a support portion 310 that movably supports the print head 200 with respect to the base frame 110, and a drive portion 320 that raises and lowers the print head 200.

[0056] The support portion 310 slidably supports the print head 200 with respect to the base frame 110 via guide rails 311L, 311R and sliders 312L, 312R. As shown in FIG. 3, the base frame 110 is provided with guide rails 311L, 311R on side wall portions 110L, 110R. The guide rails 311L, 311R are arranged along the vertical direction (Z direction). On the other hand, the print head 200 is provided with sliders 312L, 312R that slide along the guide rails 311L, 311R. The print head 200 is assembled to the base frame 110 by engaging the sliders 312L, 312R with the guide rails 311L, 311L. Thereby, the print head 200 is slidably supported with respect to the base frame 110.

[0057] The drive unit 320 raises and lowers the print head 200 by means of a so-called feed screw mechanism. As shown in FIGS. 3 and 4, a screw shaft 321 is arranged along the vertical direction (Z direction) on one side wall portion 110L of the base frame 110. The screw shaft 321 is rotatably supported via bearings 324 by brackets 322 and 323 attached to the side wall portion 110L of the base frame 110. A lifting drive motor 325 is connected to the screw shaft 321. The lifting drive motor 325 is provided on one bracket 322 and rotationally drives the screw shaft 321. A nut 326 is provided on the screw shaft 321. The nut 326 is connected to the print head 200 via a connecting bar 327. Thus, when the screw shaft 321 is rotated via the lifting drive motor 325, the nut 326 moves vertically along the screw shaft 321. Then, as the nut 326 moves vertically, the print head 200 connected to the nut 326 moves vertically together with the nut 326.

[0058] [Cap] The cap 400 covers the nozzle surface 210 of the print head 200 when not in use, thereby suppressing solvent evaporation from the nozzles 212 and adhesion of foreign matter to the nozzle surface.

[0059] As shown in FIGS. 3 and 4, the cap 400 has a hollow shape with an opening on the surface covering the nozzle surface 210. By making the cap 400 have a hollow shape, it is possible to prevent the cap 400 from directly contacting the nozzles 212. Also, a liquid (including ink) can be held inside the cap 400. In the present embodiment, the cap 400 has a rectangular flat plate shape, and a rectangular recess 410 is provided on the surface covering the nozzle surface 210. The recess 410 has a width in the longitudinal direction (a direction orthogonal to the conveyance direction of the paper P) that is slightly wider than the width in the longitudinal direction of the nozzle surface 210. Also, the width in the direction orthogonal to the longitudinal direction (the conveyance direction of the paper P) has the same or slightly wider width as the width in the direction orthogonal to the longitudinal direction of the nozzle surface 210.

[0060] As shown in FIGS. 3 and 4, the cap 400 is positioned directly below the print head 200 and covers the nozzle surface 210 of the print head 200. At this time, the surface of the cap 400 that covers the nozzle surface 210 (the upper surface in FIGS. 3 and 4) is parallel to the nozzle surface 210 (including the range recognized as substantially parallel).

[0061] [Cap opening and closing mechanism] The cap opening and closing mechanism 500 moves the cap 400 between an open position and a closed position to open and close the cap 400. The open position is the position where the nozzle surface 210 is opened, and the closed position is the position where the nozzle surface 210 is covered. The cap 400 moves between the open position and the closed position by swinging (circular arc motion) about an axis (rod) provided on the print head 200. In the present embodiment, the closed position is an example of the third position, and the open position is an example of the fourth position. Also, the swinging about the axis (rod) is an example of circular arc motion.

[0062] The cap opening and closing mechanism 500 opens and closes the cap 400 by utilizing the elevation of the print head 200. Therefore, the cap 400 opens and closes in conjunction with the elevation of the print head 200. In the present embodiment, the cap opening and closing mechanism 500 is an example of an interlocking mechanism.

[0063] FIG. 7 is a side view showing the configuration of the cap opening and closing mechanism. FIG. 8 is a front view showing the configuration of the cap opening and closing mechanism.

[0064] As shown in FIGS. 7 and 8, the print head 200 is provided with round bar-shaped rods 510 on both side surfaces. The rods 510 are arranged parallel to the nozzle surface 210 (including the range recognized as substantially parallel) and along the arrangement direction of the nozzles 212 (the longitudinal direction of the nozzle surface 210). The rods 510 function as axes for supporting the cap 400.

[0065] The cap 400 is provided with arm portions 420 at both longitudinal ends. The arm portions 420 are provided with mounting holes 421 at their tip portions (the upper end portions in FIGS. 7 and 8). The mounting hole 421 is configured as a hole into which the rod 510 can be inserted.

[0066] The cap 400 is attached to the print head 200 by inserting the rod 510 into the mounting hole 421. The cap 400 attached to the print head 200 is swingably supported about the rod 510 as an axis (swing axis).

[0067] The cap 400 is biased in the opening direction (the direction of swinging from the closed position to the open position) by a spring 511 attached to the rod 510. The spring 511 is composed of, for example, a torsion spring (twisted coil spring). One end of the spring 511 is hooked on a spring hooking portion 512 provided on the print head 200, and the other end is hooked on a spring hooking portion 513 provided on the arm portion 420 to bias the cap 400 in the opening direction. In the present embodiment, the spring 511 is an example of a biasing member.

[0068] The cap 400 is provided with levers 430 at both longitudinal ends. The lever 430 has a cylindrical shaft portion 431 at its base end portion, and the shaft portion 431 is fixed to the tip of the arm portion 420 and integrated with the arm portion 420. The cylindrical shaft portion 431 has an inner diameter into which the rod 510 can be inserted and is arranged coaxially with the mounting hole 421 of the arm portion 420. When the cap 400 is attached to the print head 200, the rod 510 is also inserted into the shaft portion 431 of the lever 430. Therefore, the lever 430 swings about the rod 510. When the lever 430 swings, the arm portion 420 of the cap 400 integrated with the lever 430 also swings about the rod 510. Therefore, the cap 400 also swings.

[0069] The print head 200 is provided with stopper pins 520 on both side surfaces. The stopper pins 520 are arranged parallel to the rod 510. The cap 400 biased in the opening direction by the spring 511 is held at a predetermined position when the lever 430 abuts against the stopper pin 520. In the present embodiment, at the open position, the lever 430 abuts against the stopper pin 520.

[0070] The base frame 110 is provided with contacts 530 on the side wall portions 110L and 110R on both sides corresponding to the lever 430 of the cap 400. The contacts 530 are attached to predetermined positions of the base frame 110 via brackets 531. In the present embodiment, the contacts 530 are constituted by rollers. The contacts 530 are rotatably held around an axis parallel to the rod 510.

[0071] The contact 530 abuts (engages) against the lever 430 of the cap 400 attached to the print head 200. The cap 400 biased by the spring 511 is held in a predetermined posture when the lever 430 abuts against the contact 530.

[0072] The contact 530 is held at a fixed position on the base frame 110. Therefore, when the print head 200 is slid (lifted and lowered) with respect to the base frame 110, the lever 430 is pushed by the contact 530 and swings. As a result, the cap 400 swings (circular arc motion) about the rod 510 and moves between the open position and the closed position. In the present embodiment, the contact 530 is an example of an engagement member.

[0073] [Opening and closing operation of the cap] As described above, the cap 400 of the present embodiment opens and closes in conjunction with the lifting and lowering of the print head 200.

[0074] FIG. 9 is a diagram for explaining the lifting and lowering operation of the print head.

[0075] The print head 200 is arranged such that the nozzle surface 210 at the tip faces the paper P conveyed by the paper conveyance unit 10. In the present embodiment, since the paper P is conveyed horizontally, the nozzle surface 210 is arranged horizontally facing the paper P.

[0076] The print head 200 is driven by the print head elevating mechanism 300 to move up and down. In the present embodiment, with respect to the horizontally conveyed paper P, the print head 200 moves vertically up and down. The print head 200 moves away from the paper P by ascending and approaches the paper P by descending.

[0077] FIG. 9(A) shows the position of the print head 200 during standby (when not in use). As shown in FIG. 9(A), during standby, the print head 200 is positioned at a position where the nozzle surface 210 is significantly separated from the belt 11. The position of the print head 200 during standby is referred to as the "standby position".

[0078] FIG. 9(B) shows the position of the print head 200 during printing. As shown in FIG. 9(B), during printing, the print head 200 approaches the belt 11 with the nozzle surface 210. The position of the print head 200 during printing is referred to as the "printing position". At the printing position, the print head 200 is positioned such that the nozzle surface 210 is at a position at a predetermined height from the paper P.

[0079] The cap 400 swings in conjunction with the elevation of the print head 200 and is automatically opened and closed. Specifically, when the print head 200 moves to the "standby position", it moves to the "closed position", and when it moves to the "printing position", it moves to the "open position".

[0080] In the present embodiment, the standby position of the print head 200 is an example of the first position, and the printing position is an example of the second position.

[0081] [Opening operation] FIG. 10 is a diagram showing the change in the state of the cap due to the elevation of the print head.

[0082] FIG. 10(A) shows the state where the print head 200 is located at the standby position. FIG. 10(C) shows the state where the print head 200 is located at the printing position. FIG. 10(B) shows the state where the print head 200 is located between the standby position and the printing position.

[0083] As shown in FIG. 10(A), when the print head 200 is located at the standby position, the cap 400 is located at the closed position. In the closed position, the cap 400 is located directly below the print head 200, and the surface (opening surface) having the opening of the recess 410 is disposed to face the nozzle surface 210. Thereby, the nozzle surface 210 is covered with the cap 400. That is, the nozzle surface 210 is capped.

[0084] With respect to the cap 400 located at the closed position, the nozzle region 211 of the nozzle surface 210 is disposed inside the opening of the recess 410. Thereby, for example, when performing preliminary ejection or purge, the ink ejected or discharged from the nozzle 212 can be recovered by the recess 410.

[0085] The cap 400 is held in the closed position by the levers 430 at both ends abutting against the contacts 530 provided on the base frame 110. That is, with respect to the cap 400 biased in the opening direction, the contacts 530 function as stoppers to hold the cap 400 in the closed position.

[0086] As shown in FIG. 10(B), when the print head 200 descends from the standby position toward the printing position, the cap 400 moves (swings) from the closed position toward the open position in conjunction with this. At this time, the cap 400 moves from the closed position toward the open position by the biasing force of the spring 511.

[0087] As shown in FIG. 10(C), when the print head 200 further descends and is positioned at the printing position, the cap 400 moves to the open position. In the open position, the cap 400 completely retracts from below the print head 200 and is positioned on the front side. In the present embodiment, it rotates 90 degrees from the closed position to the open position. Therefore, the cap 400 is held in a posture where the opening surface is perpendicular to the nozzle surface 210.

[0088] When the cap 400 is positioned at the open position and retracts from below the print head 200, the nozzle surface 210 is opened. As a result, ink droplets can be ejected toward the paper P.

[0089] The cap 400 is held in the open position when the levers 430 at both ends contact the contacts 530. That is, the contacts 530 function as stoppers for the cap 400 that is biased in the opening direction, thereby holding it in the open position.

[0090] In the present embodiment, when the print head 200 is positioned at the printing position, the lever 430 contacts the stopper pin 520. Therefore, the movement of the cap 400 is also blocked by the stopper pin 520. When the lever 430 contacts the stopper pin 520, even if the print head 200 moves further downward from the printing position, the cap 400 is held in the open position.

[0091] [Closing operation] When the print head 200 rises from the printing position toward the standby position, the lever 430 of the cap 400 is pushed by the contacts 530 against the biasing force of the spring 511. As a result, the cap 400 swings in the closing direction (the direction from the open position to the closed position).

[0092] As shown in FIG. 10(A), when the print head 200 moves to the standby position, the cap 400 is positioned at the closed position. As a result, the nozzle surface 210 is covered by the cap 400. The cap 400 is held in the closed position because the lever 430 is in contact with the contacts 530.

[0093] Thus, according to the cap mechanism of the present embodiment, the cap 400 is automatically opened and closed in conjunction with the lifting operation (forward and backward movement) of the print head 200. Thereby, the nozzle surface 210 can be surely capped at the standby position. Also, the nozzle surface 210 can be surely opened at the printing position.

[0094] Further, according to the present embodiment, since no separate power is required for opening and closing the cap 400, the configuration of the cap mechanism can be simplified. Also, thereby, the entire printing machine including the cap mechanism can be made compact.

[0095] [Modification Example] [Modification Example of Cap Opening and Closing Mechanism] (1) First Modification Example of Cap Opening and Closing Mechanism FIG. 11 is a diagram showing a first modification example of the cap opening and closing mechanism.

[0096] The cap opening and closing mechanism 500 of this example shows an example in which the cap 400 is biased in the opening direction. In this case, the cap 400 is biased by a spring (not shown) in the direction from the open position to the closed position (clockwise direction in FIG. 11).

[0097] FIG. 12 is a diagram showing changes in the state of the cap due to the lifting of the print head.

[0098] FIG. 12(A) shows the state where the print head 200 is located at the standby position. FIG. 12(C) shows the state where the print head 200 is located at the printing position. FIG. 12(B) shows the state where the print head 200 is located between the standby position and the printing position.

[0099] The cap 400 biased in the closing direction is held at a predetermined position with respect to the print head 200 when the lever 430 abuts against the contact 530. The contact 530 functions as a stopper, thereby being held at a predetermined position.

[0100] As shown in Fig. 12(A), when the print head 200 is in the standby position, the cap 400 is in the closed position. In the closed position, the cap 400 is located directly below the print head 200, and the opening surface is arranged to face the nozzle surface 210. Thereby, the nozzle surface 210 is covered by the cap 400.

[0101] As shown in Fig. 12(B), when the print head 200 descends from the standby position toward the printing position, due to the action of the contact 530, the lever 430 of the cap 400 is pulled upward in the opening direction against the biasing force of the spring. As a result, the cap 400 swings in the opening direction.

[0102] As shown in Fig. 12(C), when the print head 200 is in the printing position, the cap 400 swings to the open position. In the open position, the cap 400 completely retracts from below the print head 200. Thereby, the nozzle surface 210 is opened, and ink droplets can be ejected from the nozzles 212 toward the paper P.

[0103] When the print head 200 rises from the printing position toward the standby position, the cap 400 swings in the closing direction by the biasing force of the spring. When the print head 200 moves to the standby position, the cap 400 is in the closed position, and the nozzle surface 210 is covered by the cap 400.

[0104] Thus, also by the cap opening / closing mechanism 500 of this example, the cap 400 can be automatically opened and closed in conjunction with the lifting and lowering operation of the print head 200.

[0105] In this example, in the closed position, the stopper pin 520 is configured to contact the arm portion 420 of the cap 400. Therefore, when the print head 200 moves to the standby position, the cap 400 is held in the closed position by the stopper pin 520. In this case, even if the print head 200 further rises, the cap 400 is held in the closed position.

[0106] (2) Second Modified Example of Cap Opening / Closing Mechanism FIG. 13 is a diagram showing a second modified example of the cap opening / closing mechanism.

[0107] In the cap opening / closing mechanism 500 of this example, the cap 400 is opened and closed using a gear. Specifically, a rack and pinion are used to convert the linear motion of the print head 200 caused by lifting and lowering into the rotational motion (swinging) of the cap 400, thereby opening and closing the cap 400.

[0108] The cap 400 is provided with a pinion 540. The pinion 540 is provided at the tips (upper ends in FIG. 13) of the arm portions 420 on both sides and is arranged coaxially with the mounting hole 421. Further, the pinion 540 is fixedly attached to the arm portion 420. Therefore, when the pinion 540 is rotated about its axis, the arm portion 420 also rotates integrally with the pinion 540.

[0109] For the cap 400 attached to the print head 200, the pinion 540 is arranged coaxially with the rod 510. Therefore, when the pinion 540 is rotated, the arm portion 420 rotates about the rod 510. As a result, the cap 400 swings about the rod 510. That is, when the pinion 540 is rotated, the cap 400 swings.

[0110] The base frame 110 is provided with a rack 541 that meshes with the pinion 540. The rack 541 is attached to the side wall portions 110L and 110R of the base frame 110 via a bracket 542. The rack 541 is arranged along the moving direction of the print head 200. In the present embodiment, the print head 200 moves vertically (lifts and lowers) perpendicular to the horizontal plane. Therefore, the rack 541 is arranged along the vertical direction (Z direction in FIG. 13).

[0111] When the print head 200 moves up and down with respect to the base frame 110, the rack 541 reciprocates linearly with respect to the pinion 540. As a result, the pinion 540 rotates and the cap 400 swings. Further, when the print head 200 stops, the posture of the cap 400 is maintained by the action of the pinion 540 meshing with the rack 541.

[0112] FIG. 14 is a diagram showing changes in the state of the cap due to the up and down movement of the print head.

[0113] FIG. 14(A) shows a state where the print head 200 is located at the standby position. FIG. 14(C) shows a state where the print head 200 is located at the printing position. FIG. 14(B) shows a state where the print head 200 is located between the standby position and the printing position.

[0114] As shown in FIG. 14(A), when the print head 200 is located at the standby position, the cap 400 is located at the closed position. In the closed position, the cap 400 is located directly below the print head 200, and the opening surface is arranged to face the nozzle surface 210. Thereby, the nozzle surface 210 is covered with the cap 400.

[0115] As shown in FIG. 14(B), when the print head 200 descends from the standby position toward the printing position, the pinion 540 descends with respect to the stationary rack 541. As a result, the pinion 540 rotates in the opening direction (counterclockwise direction in FIG. 14), and the cap 400 swings in the opening direction.

[0116] When further descending and as shown in FIG. 14(C), when the print head 200 is located at the printing position, the cap 400 swings to the open position. In the open position, the cap 400 completely retracts from below the print head 200. Thereby, the nozzle surface 210 is opened, and ink droplets can be ejected toward the paper P.

[0117] When the print head 200 rises from the printing position toward the standby position, the pinion 540 rises with respect to the stationary rack 541. As a result, as shown in FIG. 14(B), the pinion 540 rotates in the closing direction (the clockwise direction in FIG. 14), and the cap 400 swings in the closing direction. When the print head 200 moves to the standby position, as shown in FIG. 14(A), the cap 400 is positioned at the closed position, and the nozzle surface 210 is covered with the cap 400.

[0118] Thus, also with the cap opening / closing mechanism 500 of this example, the cap 400 can be automatically opened and closed in conjunction with the raising and lowering operation of the print head 200.

[0119] In this example, the rack 541 and the pinion 540 constitute the cap opening / closing mechanism 500, but the cap opening / closing mechanism 500 may be further configured by combining gears. Also, in this example, the spring as the biasing member is generally unnecessary.

[0120] (3) Third Modified Example of Cap Opening / Closing Mechanism FIG. 15 is a diagram showing a third modified example of the cap opening / closing mechanism.

[0121] The cap opening / closing mechanism 500 of this example opens and closes the cap 400 using a so-called link mechanism. FIG. 15 shows an example using a slider link mechanism.

[0122] As shown in FIG. 15, one end of a first link 552 is connected to both side wall portions 110L and 110R of the base frame 110 via a first joint 551 (only the first link 552 connected to one side wall portion 110L is shown in FIG. 15). The other end of the first link 552 is connected to one end of a second link 554 via a second joint 553. The other end of the second link 554 is connected to the print head 200 via a rod 510.

[0123] The print head 200 functions as a slider in the slider link mechanism. When the print head 200 slides (moves up and down) with respect to the base frame 110, the second link 554 swings about the rod 510.

[0124] The arm portion 420 is fixed to the swinging second link 554. As a result, the arm portion 420 swings in conjunction with the second link 554. Then, as the arm portion 420 swings, the cap 400 swings about the rod 510.

[0125] FIG. 16 is a diagram showing changes in the state of the cap due to the up and down movement of the print head.

[0126] FIG. 16(A) shows the state where the print head 200 is located at the standby position. FIG. 16(C) shows the state where the print head 200 is located at the printing position. FIG. 16(B) shows the state where the print head 200 is located between the standby position and the printing position.

[0127] As shown in FIG. 16(A), when the print head 200 is located at the standby position, the cap 400 is located at the closed position. In the closed position, the cap 400 is located directly below the print head 200, and the opening surface is arranged to face the nozzle surface 210. Thereby, the nozzle surface 210 is covered by the cap 400.

[0128] As shown in FIG. 16(B), when the print head 200 descends from the standby position toward the printing position, the second link 554 swings in the opening direction (counterclockwise direction in FIG. 16) about the rod 510. As a result, the cap 400 fixed to the second link 554 swings in the opening direction via the arm portion 420.

[0129] Further descending, as shown in FIG. 16(C), when the print head 200 is positioned at the printing position, the cap 400 swings to the open position. At the open position, the cap 400 completely retracts from below the print head 200. Thereby, the nozzle surface 210 is opened, enabling the ejection of ink droplets toward the paper P.

[0130] When the print head 200 rises from the printing position toward the standby position, with the rod 510 as the axis, the second link 554 swings in the closing direction (clockwise direction in FIG. 16). As a result, as shown in FIG. 16(B), the cap 400 fixed to the second link 554 swings in the closing direction via the arm portion 420. When the print head 200 moves to the standby position, as shown in FIG. 16(A), the cap 400 is positioned at the closed position, and the nozzle surface 210 is covered by the cap 400.

[0131] Thus, also with the cap opening / closing mechanism 500 of this example, the cap 400 can be automatically opened and closed in conjunction with the lifting and lowering operation of the print head 200.

[0132] (4) Fourth Modified Example of Cap Opening / Closing Mechanism FIG. 17 is a diagram showing a fourth modified example of the cap opening / closing mechanism.

[0133] The cap opening / closing mechanism 500 of this example uses a so-called cam mechanism to open and close the cap 400.

[0134] As shown in FIG. 17, the base frame 110 is provided with plate cams 561 on both side wall portions 110L and 110R on both sides (only the plate cam 561 of one side wall portion 110L is shown in FIG. 17). The plate cams 561 are provided on both side wall portions 110L and 110R of the base frame 110 via brackets 562.

[0135] The cap 400 is provided with levers 563 at the tips of the arm portions 420 on both sides. The lever 563 has a cylindrical shaft portion 564 at the base end portion, and the shaft portion 564 is fixed to the tip of the arm portion 420 and integrated with the arm portion 420. The shaft portion 564 has an inner diameter into which the rod 510 can be inserted and is arranged coaxially with the mounting hole 421 of the arm portion 420.

[0136] The tip of the lever 563 is provided with a contact 565 that engages with the plate cam 561. The contact 565 is composed of a roller. The plate cam 561 is composed of a so-called direct-acting cam (linear cam) and linearly moves relative to the print head 200.

[0137] The cap 400 is biased in the closing direction (clockwise direction in FIG. 17) by a spring (not shown). Thereby, the contact 565 is pressed against the plate cam 561.

[0138] When the print head 200 moves up and down, the lever 563 swings due to the action of the contact 565 and the plate cam 561. Thereby, the cap 400 is opened and closed.

[0139] FIG. 18 is a diagram showing changes in the state of the cap due to the up and down movement of the print head.

[0140] FIG. 18(A) shows the state where the print head 200 is located at the standby position. FIG. 18(C) shows the state where the print head 200 is located at the printing position. FIG. 18(B) shows the state where the print head 200 is located between the standby position and the printing position.

[0141] As shown in FIG. 18(A), when the print head 200 is located at the standby position, the cap 400 is located at the closed position. In the closed position, the cap 400 is located directly below the print head 200, and the opening surface is arranged to face the nozzle surface 210. Thereby, the nozzle surface 210 is covered by the cap 400.

[0142] As shown in Fig. 18(B), when the print head 200 descends from the standby position toward the printing position, due to the action of the contact 565 and the plate cam 561, the lever 563 swings in the opening direction (counterclockwise direction in Fig. 18) against the biasing force of the spring. As a result, the cap 400 swings in the opening direction.

[0143] When it further descends and the print head 200 is positioned at the printing position as shown in Fig. 18(C), the cap 400 swings to the open position. At the open position, the cap 400 completely retracts from below the print head 200. Thereby, the nozzle surface 210 is opened, and ink droplets can be ejected toward the paper P.

[0144] When the print head 200 ascends from the printing position toward the standby position, due to the action of the contact 565 and the plate cam 561, the lever 563 swings in the closing direction (clockwise direction in Fig. 18). As a result, as shown in Fig. 18(B), the cap 400 swings in the closing direction. When the print head 200 moves to the standby position, as shown in Fig. 18(A), the cap 400 is positioned at the closed position, and the nozzle surface 210 is covered by the cap 400.

[0145] Thus, also with the cap opening / closing mechanism 500 of this example, the cap 400 can be automatically opened and closed in conjunction with the ascending / descending operation of the print head 200.

[0146] Note that this example is an example when the cap opening / closing mechanism is constituted by a cam mechanism, but the cap opening / closing mechanism of the above first embodiment is also an example when it is constituted by a cam mechanism.

[0147] (5) Other Modification Examples of the Cap Opening / Closing Mechanism The cap opening / closing mechanism 500 of the above first embodiment employs a torsion spring as a means for biasing the cap 400 in the opening direction, but the means for biasing the cap 400 is not limited to this. Additionally, a tension coil spring, a spiral spring, a leaf spring, etc. can also be employed.

[0148] In addition, each of the above-described modified examples employs a gear mechanism including a rack and a pinion, a link mechanism, and a cam mechanism as a mechanism for converting the linear motion of the print head 200 into an arc motion by the cap 400. However, the mechanism for converting the linear motion of the print head 200 into the rotational motion of the cap 400 is not limited to this. Other conversion mechanisms can also be used. Further, in the above-described modified example, the cam mechanism, the link mechanism, and the gear mechanism are configured to be used alone, but a configuration in which these are appropriately combined can also be adopted.

[0149] [Modified Example of Cap] (1) First Modified Example of Cap FIG. 19 is a view showing a first modified example of the cap. FIG. 19 shows a cross-sectional shape of the cap 400 in a cross-section orthogonal to the swing axis. In FIG. 19, the solid line indicates a state where the cap 400 is in the closed position, and the broken line indicates a state where the cap 400 is in the open position.

[0150] As shown in FIG. 19, the cap 400 of this example has an arc shape in a cross-section orthogonal to the swing axis. The arc forms a part of a circle centered on the swing axis. That is, the cap 400 of this example has a shape obtained by cutting out a part of a cylinder.

[0151] By having an arc shape, the cap 400 is provided with an arc-shaped recess 410 on the surface covering the nozzle surface 210. That is, the cap 400 has a hollow shape in which the surface covering the nozzle surface 210 is open.

[0152] By having the recess 410 on the surface covering the nozzle surface 210, the cap 400 can collect, for example, the ink discharged or ejected from the nozzle 212 when performing preliminary discharge or purge.

[0153] Thus, it is preferable that the cap 400 is provided with the recess 410 on the surface covering the nozzle surface 210. That is, it is preferable that the cap 400 has a hollow shape in which the surface covering the nozzle surface 210 is open.

[0154] In a hollow-shaped cap with an opening in the surface covering the nozzle surface, the peripheral edge of the opening constitutes the part closest to the swing axis in a cross-section orthogonal to the swing axis. In other words, in a cross-section orthogonal to the swing axis, a cap in which the part closest to the swing axis forms an edge has a hollow shape with an opening in the surface covering the nozzle surface.

[0155] (2) Second modification example of the cap FIG. 20 is a view showing a second modification example of the cap. FIG. 20 shows the cross-sectional shape of the cap 400 in a cross-section orthogonal to the swing axis.

[0156] As shown in FIG. 20, the cap 400 of this example is provided with a partition plate 411 inside (inside the recess 410), and the inside is divided into two in the depth direction. The space on the bottom side with the partition plate 411 interposed therebetween is the first space 410A, and the space on the opening side is the second space 410B. The first space 410A and the second space 410B communicate with each other at one end (the right end in FIG. 20) of the partition plate 411.

[0157] The first space 410A is used as a space for storing a liquid for moisturizing (moisturizing liquid). On the other hand, the second space 410B is used as a space for collecting the ink discharged or ejected from the nozzle 212.

[0158] The first space 410A is provided with a supply port 440a and a recovery port 440b for the moisturizing liquid 460.

[0159] A moisturizing liquid supply pipe 441a is connected to the supply port 440a. The moisturizing liquid supply pipe 441a is connected to a moisturizing liquid supply tank 444a via a moisturizing liquid supply valve 442a and a moisturizing liquid supply pump 443a. The moisturizing liquid supply tank 444a stores unused moisturizing liquid. By opening the moisturizing liquid supply valve 442a and driving the moisturizing liquid supply pump 443a, the moisturizing liquid stored in the moisturizing liquid supply tank 444a is supplied to the first space 410A.

[0160] A moisturizing liquid recovery pipe 441b is connected to the recovery port 440b. The moisturizing liquid recovery pipe 441b is connected to a moisturizing liquid recovery tank 444b via a moisturizing liquid recovery valve 442b and a moisturizing liquid recovery pump 443b. Used moisturizing liquid is stored in the moisturizing liquid recovery tank 444b. By opening the moisturizing liquid recovery valve 442b and driving the moisturizing liquid recovery pump 443b, the moisturizing liquid stored in the first space 410A is recovered into the moisturizing liquid recovery tank 444b.

[0161] A drain port 450 is provided in the second space 410B. A drain pipe 451 is connected to the drain port 450. The drain pipe 451 is connected to a waste liquid tank 454 via a drain valve 452 and a drain pump 453. Ink recovered in the second space 410B is stored in the waste liquid tank 454. By opening the drain valve 452 and driving the drain pump 453, the ink recovered in the second space 410B is recovered into the waste liquid tank 454.

[0162] The recovery of the ink is performed with the cap 400 closed (capping state). That is, it is performed in the closed position. As shown in FIG. 20, in the closed position, the partition plate 411 is disposed inclined toward the drain port 450. More specifically, it is disposed inclined from the horizontal state so that the drain port 450 side is lower. Thereby, by utilizing gravity, the recovered ink can be naturally guided to the drain port 450.

[0163] When moisturizing the nozzle surface 210, a moisturizing liquid 460 is stored in the first space 410A of the cap 400. For the moisturizing liquid 460, the moisturizing liquid supply valve 442a is opened and the moisturizing liquid supply pump 443a is driven. Thereby, the moisturizing liquid is supplied from the moisturizing liquid supply tank 444a to the first space 410A. After a certain amount is supplied, the driving of the moisturizing liquid supply pump 443a is stopped and the moisturizing liquid supply valve 442a is closed. Thereby, the moisturizing liquid 460 is stored in the first space 410A. By storing the moisturizing liquid 460 in the first space 410A, the inside of the recess 410 is moistened and the nozzle surface 210 is moisturized.

[0164] When recovering the moisturizing liquid 460, open the moisturizing liquid recovery valve 442b and drive the moisturizing liquid recovery pump 443b. Thereby, the moisturizing liquid 460 is recovered from the first space 410A through the recovery port 440b. The recovered moisturizing liquid is stored in the moisturizing liquid recovery tank 444b.

[0165] When performing purging or preliminary discharging, it is carried out with the cap 400 positioned in the closed position. The ink discharged or ejected from the nozzle 212 by purging or preliminary discharging is recovered by the partition plate 411 and stored in the second space 410B.

[0166] When recovering the ink stored in the second space 410B, open the drain valve 452 and drive the drain pump 453. Thereby, the ink is recovered from the second space 410B through the drain port 450. The recovered ink is stored in the waste liquid tank 454.

[0167] FIG. 21 is a diagram showing the change in the state of the moisturizing liquid due to the swinging of the cap.

[0168] FIG. 21(A) shows the state where the cap 400 is positioned in the closed position. FIG. 21(C) shows the state where the cap 400 is positioned in the open position. FIG. 21(B) shows the state where the cap 400 is positioned between the closed position and the open position.

[0169] As shown in FIG. 21, when the cap 400 is swung from the closed position toward the open position, the cap 400 gradually tilts from the horizontal state. When the cap 400 tilts, the moisturizing liquid 460 stored in the recess 410 tends to flow out from the opening of the recess 410. However, in the cap 400 of this example, since the partition plate 411 is provided in the recess 410, the outflow of the moisturizing liquid 460 is blocked by the partition plate 411. Therefore, as shown in FIGS. 21(B) and (C), even when the cap 400 is tilted or erected, the moisturizing liquid 460 can be held in the recess 410. In this modification, the partition plate 411 is an example of a weir portion.

[0170] Thus, according to the cap 400 of this example, even if the cap 400 is swung for opening and closing, the moisturizing liquid 460 can be held in the recess 410. Further, the ink discharged or ejected from the nozzle 212 can be recovered without being mixed with the moisturizing liquid 460.

[0171] (3) Third Modification Example of the Cap FIG. 22 is a diagram showing a third modification example of the cap.

[0172] FIG. 22 shows a modified example of the cap 400 provided with a partition plate 411. FIG. 22(A) shows the state of the cap 400 during capping. FIG. 22(B) shows the state of the cap 400 during purging.

[0173] As shown in FIG. 22(A), the cap 400 of this example is different from the cap 400 shown in FIG. 20 in that the partition plate 411 is horizontally arranged in the closed position.

[0174] In the closed position, since the partition plate 411 is horizontally arranged, if ink is discharged or ejected from the nozzle 212 during capping, the ink received by the partition plate 411 may flow into the first space 410A.

[0175] Therefore, as shown in FIG. 22(B), when purging or pre-ejecting with the cap 400 of this example, the cap 400 is tilted. Thereby, the ink discharged or ejected from the nozzle 212 can be recovered without being mixed with the moisturizing liquid 460.

[0176] Note that also in this modification example, the partition plate 411 has a function of blocking the moisturizing liquid 460 stored in the recess 410. Therefore, also in this modification example, the partition plate 411 functions as a weir portion.

[0177] (4) Other Modification Examples of the Cap In the above example, a configuration is adopted in which a pump is used to supply and recover the moisturizing liquid to and from the cap 400. However, a configuration in which the moisturizing liquid is supplied and recovered to and from the cap 400 by using gravity may also be employed. In this case, for example, a moisturizing liquid supply tank 444a is installed at a position higher than the cap 400, and a moisturizing liquid recovery tank 444b is installed at a position lower than the cap 400. The same applies to the ink recovered by purging or the like, and a configuration in which it is recovered by using gravity may also be employed.

[0178] When using the moisturizing liquid, a liquid absorbent may be provided in the recess 410. Thereby, the moisturizing liquid can be efficiently held in the recess 410. Further, when the cap 400 is swung, it is possible to prevent the moisturizing liquid from flowing out from the opening.

[0179] When the partition plate 411 is arranged in the recess 410, the liquid absorbent may be arranged in both the first space 410A and the second space 410B.

[0180] As the liquid absorbent, for example, a porous body such as a sponge can be adopted.

[0181] [Second Embodiment] In the case of a configuration in which the cap is swung to open and close, it is necessary to design such that the swinging cap does not contact the print head. In order to avoid contact between the cap and the print head, it is necessary to secure a clearance between the cap and the print head. However, if the clearance is increased, a large gap is generated between the cap and the print head during capping, and the sealing effect by the cap is reduced. In the present embodiment, a print head unit capable of improving the sealing effect by the cap will be described.

[0182] FIGS. 23 and 24 are diagrams showing the configuration of the main part of the print head unit. FIG. 23 shows a partial cross section at an intermediate position in the longitudinal direction of the print head 200. FIG. 24 shows a partial cross section at one end in the longitudinal direction of the print head 200.

[0183] As shown in FIGS. 23 and 24, the print head unit 100 of the present embodiment has a seal 600 that can be elastically deformed on the print head 200. The configuration other than having the seal 600 is the same as that of the print head unit 100 of the first embodiment. Therefore, in the following, only the configuration and the effects of the seal 600 will be described.

[0184] The seal 600 is provided along the peripheral edge of the tip of the print head 200. The seal 600 is composed of a front and rear seal portion 601 provided along the front and rear edges (the upstream and downstream edges in the paper conveyance direction) of the print head 200, and both end seal portions 602 provided at both ends in the longitudinal direction of the print head 200. The front and rear seal portions 601 have a linear shape at their tips. The both end seal portions 602 have an arc-shaped shape at their tips. The tips of the both end seal portions 602 form a part of a circle centered on the rod 510. The front and rear seal portions 601 and the both end seal portions 602 are attached to the print head 200 via a holder 603.

[0185] When the cap 400 is in the closed position, the tip portions of the front and rear seal portions 601 and the both end seal portions 602 are pressed against the peripheral edge of the opening of the cap 400. Specifically, as shown in FIG. 23, the front and rear seal portions 601 are pressed against the front and rear peripheral edge portions (the upstream and downstream peripheral edge portions in the paper conveyance direction) of the opening of the cap 400. Also, as shown in FIG. 24, the both end seal portions 602 are pressed against the peripheral edge portions at both ends in the longitudinal direction of the cap 400. The portions of the cap 400 (the peripheral edge portions at both ends in the longitudinal direction of the recess 410) where the both end seal portions 602 are in contact have an arc-shaped shape corresponding to the shape of the tips of the both end seal portions 602.

[0186] According to the print head unit 100 of the present embodiment configured as described above, when the cap 400 is in the closed position, the front and rear seal portions 601 and the both end seal portions 602 are pressed against the peripheral edge of the opening of the cap 400. Thereby, the periphery of the opening is sealed by the seal 600. Since the seal 600 can be elastically deformed, it does not hinder the movement of the cap 400 even when they are in contact.

[0187] Thus, according to the print head unit 100 of the present embodiment, it is possible to improve the sealing performance during capping while ensuring the clearance necessary for opening and closing the cap 400.

[0188] In the above embodiment, the configuration is such that the seal 600 is provided on the print head side, but a configuration in which the seal is provided on the cap side may also be used.

[0189] Also, in the above embodiment, the configuration is such that the entire circumference of the print head 200 is sealed, but a configuration in which only the front-rear direction is sealed may also be used. In this case, it is preferable to set the clearances at both ends in the longitudinal direction as small as possible.

[0190] The material of the seal 600 is not particularly limited. Any material that can be elastically deformed and can ensure sealing performance may be used. In the present embodiment, the seal 600 is an example of a sealing member.

[0191] [Third Embodiment] FIG. 25 is a diagram showing the configuration of the main part of the third embodiment of the print head unit.

[0192] The print head unit of the present embodiment has a locking mechanism for locking the cap in the closed position. Note that it is the same as the print head unit 100 of the first embodiment described above except for having the locking mechanism. Therefore, in the following, only the configuration and the operation and effect of the locking mechanism will be described.

[0193] In this embodiment, the locking mechanism is configured by a push latch mechanism that uses a push latch 700. The push latch mechanism is a latch mechanism that locks and unlocks (releases the lock) by a pushing operation. As shown in FIG. 25, the push latch 700 is composed of a push latch body 701 and a strike 702. The push latch 700 is coupled (locked) by pushing the strike 702 into the push latch body 701, and the coupling is released (unlocked) by further pushing.

[0194] The push latch body 701 is provided on both side surfaces in the longitudinal direction of the print head 200 (only one side surface is shown in FIG. 25).

[0195] On the other hand, the strike 702 is integrally attached to the arm portion 420 of the cap 400 via a bracket 703. Therefore, when the cap 400 swings, the strike 702 swings integrally with the cap 400.

[0196] FIG. 25 shows a state where the cap 400 is in the closed position. As shown in FIG. 25, when the cap 400 is in the closed position, the push latch body 701 and the cap 400 are arranged in a positional relationship where they engage with each other.

[0197] FIG. 26 is an explanatory diagram of the locking and unlocking operations of the cap using the push latch mechanism. FIG. 26(A) is a diagram showing the state where the cap is locked. FIG. 26(B) is a diagram showing the state where the cap is unlocked.

[0198] As shown in FIG. 26(A), when the cap 400 is in the closed position, the strike 702 engages with the push latch body 701. When the strike 702 engages with the push latch body 701, the swing of the cap 400 is locked and held in the closed position.

[0199] When locked by the push latch 700, the capping state is maintained even if the lever 430 separates from the contact 530. Therefore, after locking, the locked state is maintained even if the print head 200 is lowered.

[0200] To release the lock, swing the cap 400 and push the striker 702 toward the push latch body 701. In the example shown in Fig. 26, the cap 400 is swung in the clockwise direction. The cap 400 swings in the clockwise direction by raising the print head 200. Therefore, to release the lock, raise the print head 200 by a predetermined amount (the amount required to release the lock). As a result, the striker 702 is pushed into the push latch body 701, and the engagement between the striker 702 and the push latch body 701 is released.

[0201] When the engagement between the striker 702 and the push latch body 701 is released, the lock on the cap 400 is released, and the cap 400 becomes swingable. As a result, as shown in Fig. 26(B), the cap 400 swings in conjunction with the lowering of the print head 200.

[0202] Thus, according to the print head unit 100 of the present embodiment, the cap 400 can be held in the closed position regardless of the position of the print head 200. That is, the capping state can be maintained. As a result, the capping state can be stably maintained.

[0203] In the present embodiment, a push latch mechanism is employed as the locking mechanism, but the locking mechanism is not limited to this. Any mechanism that can lock the cap 400 at a fixed position with respect to the print head 200 may be used.

[0204] Also, in the above embodiment, the cap 400 is configured to be lockable only in the closed position, but it may be configured to be lockable in the open position as well.

[0205] In addition, although the print head unit of the above embodiment is not provided with a seal, the locking mechanism can also be adopted for a print head unit provided with a seal. By adopting the locking mechanism for the print head unit provided with a seal, the seal can be surely adhered, and the sealing performance by the seal can be improved.

[0206] [Other Embodiments] [Moving Mode of Cap] In the above embodiment, the cap 400 is configured to swing (arc motion) along a circle centered on the rod 510, but the moving mode of the cap is not limited to this.

[0207] FIG. 27 is a diagram showing another example of the moving mode of the cap.

[0208] FIG. 27 shows an example in which the cap 400 swings along an elliptical moving locus. In this way, by swinging the cap 400 along the elliptical moving locus, the cap 400 can be brought close to and held by the print head 200 in the open position. Thereby, the print head unit can be miniaturized.

[0209] In addition, the cap 400 may be configured to linearly move in the paper P conveyance direction along the nozzle surface, for example, and open and close.

[0210] In the above embodiment, in the open position, the cap is configured to stand up, but it may be configured to move the cap to the open position while maintaining a horizontal state.

[0211] [Mechanism for Moving Cap] A mechanism for causing a desired operation to be performed on the cap by utilizing the movement of the print head can be realized by singly or appropriately combining a cam mechanism, a gear mechanism, a link mechanism, and the like.

[0212] In the above embodiment, the lifting drive motor 325 is used to lift and lower the print head 200 electrically. However, the print head 200 may be configured to be lifted and lowered manually.

[0213] [Inkjet recording apparatus] In the above embodiment, the case where the present invention is applied to an inkjet printer has been described as an example. However, the application of the present invention is not limited to this. The present invention can be applied to all devices (inkjet recording apparatuses) that record images on a medium by an inkjet method. Further, the medium is not limited to paper and includes various substances.

[0214] In the above embodiment, the case where the paper (medium) is conveyed by a belt has been described as an example. However, the conveyance form of the paper is not limited to this. For example, the present invention can also be applied to an inkjet recording apparatus that conveys the paper in a drum conveyance form. In an inkjet recording apparatus that conveys the paper in a drum conveyance form, the print head may be disposed obliquely. In this case, by disposing a partition plate in the concave portion of the cap, the moisturizing liquid can be held in the cap (see FIG. 20).

[0215] In the above embodiment, the case of printing on a single sheet of paper has been described as an example. However, the present invention can be similarly applied to an inkjet printer that prints on a roll of paper.

[0216] Furthermore, in the above embodiment, the case where the present invention is applied to a so-called single-pass type inkjet recording apparatus has been described as an example. However, the application of the present invention is not limited to this. It can also be applied to a so-called shuttle type inkjet recording apparatus. Note that, compared with a shuttle type inkjet recording apparatus, the recording head of a single-pass type inkjet recording apparatus becomes longer. Therefore, the present invention that can incorporate the cap mechanism into the head unit acts particularly effectively. That is, in an inkjet recording apparatus configured not to incorporate the cap mechanism into the head unit, a space for the cap and a mechanism for transporting the head unit to the position of the cap are separately required. Since a space for the cap is required for the length of the print head, in a single-pass type inkjet recording apparatus, the apparatus tends to be enlarged. By being able to incorporate the cap mechanism into the head unit, the size of the single-pass type inkjet recording apparatus can also be reduced. Therefore, the present invention acts particularly effectively in a single-pass type inkjet recording apparatus.

[0217] Also, in the above embodiment, the recording head is modularized and a plurality of head modules are joined together to form one recording head. However, the configuration of the recording head is not limited to this. A single recording head that is not modularized can also be adopted.

Explanation of Reference Numerals

[0218] 1 Inkjet Printer 10 Paper Transport Unit 11 Belt 12 Roller 12A Driving Roller 13 Belt Driving Motor 15 Suction Unit 20 Printing Unit 30 Image Reading Unit 31 Image Reading Device 100 Print Head Unit 100Bk Print Head Unit 100C Print Head Unit 100M Print Head Unit 100Y Print Head Unit 110 Base Frame 110L Side Wall 110R Side Wall 110T Top Wall 200 Print Head 200Bk Print Head 200C Print Head 200M Print Head 200Y Print Head 201 Head Module 210 Nozzle Surface 211 Nozzle Area 212 Nozzle 300 Print Head Lifting Mechanism 310 Support 311L Guide Rail 311R Guide Rail 312L Slider 312R Slider 320 Driving Section 321 Screw Shaft 322 Bracket 323 Bracket 324 Bearing 325 Lifting Driving Motor 326 Nut 327 Connecting Bar 400 Cap 410 Recess 410A First Space 410B Second Space 411 Partition Plate 420 Arm Section 421 Mounting Hole 430 Lever 431 Shaft Section 440a Supply Port 440b Recovery Port 441a Moisture Retaining Liquid Supply Pipe 441b Moisture Retaining Liquid Recovery Pipe 442a Moisture Retaining Liquid Supply Valve 442b Moisture Retaining Liquid Recovery Valve 443a Moisture Supply Pump 443b Moisture Recovery Pump 444a Moisture Supply Tank 444b Moisture Recovery Tank 450 Drain Outlet 451 Drain Pipe 452 Drain Valve 453 Drain Pump 454 Waste Liquid Tank 460 Moisture 500 Cap Opening and Closing Mechanism 510 Rod 511 Spring 512 Spring Hanging Part 513 Spring Hanging Part 520 Stopper Pin 530 Contact 531 Bracket 540 Pinion 541 Rack 542 Bracket 551 First Joint 552 First Link 553 Second Joint 554 Second Link 561 Plate Cam 562 Bracket 563 Lever 564 Shaft Part 565 Contact 600 Seal 601 Front and Rear Seal Parts 602 Both - End Seal Parts 603 Holder 700 Push Latch 701 Push Latch Body 702 Strike 703 Bracket Sheet P

Claims

1. A recording head having a nozzle surface on which a plurality of nozzles are arranged and movable between a first position and a second position, A cap provided on the recording head and movable between a third position covering the nozzle surface and a fourth position opening the nozzle surface, An interlocking mechanism that moves the cap from the third position to the fourth position by an operation of the recording head moving from the first position to the second position, and moves the cap from the fourth position to the third position by an operation of the recording head moving from the second position to the first position, A head unit comprising the above.

2. The recording head moves between the first position and the second position by linear motion, The cap moves between the third position and the fourth position by arc motion, The interlocking mechanism converts the linear motion of the recording head into the arc motion of the cap, The head unit according to claim 1.

3. The interlocking mechanism includes: A biasing member that biases the cap toward the fourth position, An engaging member that engages with the cap at a fixed position with respect to the recording head moving from the second position to the first position and moves the cap from the fourth position toward the third position against the biasing force of the biasing member, Comprising the above, The head unit according to claim 2.

4. The interlocking mechanism includes: A biasing member that biases the cap toward the third position, An engaging member that engages with the cap at a fixed position with respect to the recording head moving from the first position to the second position and moves the cap from the third position toward the fourth position against the biasing force of the biasing member, Comprising the above, The head unit according to claim 2.

5. The interlocking mechanism is composed of a combination of gears including a rack and a pinion, The head unit according to claim 2.

6. The interlocking mechanism is composed of a cam mechanism or a link mechanism that converts linear motion into arc motion, The head unit according to claim 2.

7. The cap has an open hollow shape, and at the third position, the opening is arranged facing the nozzle surface, The head unit according to any one of claims 1 to 6.

8. Further comprising a sealing member provided on the recording head or the cap and sealing the periphery of the opening between the cap located at the third position and the recording head, The head unit according to claim 7.

9. The head unit according to claim 8, further comprising a locking mechanism for locking the cap located at the third position.

10. The head unit according to claim 9, wherein the locking mechanism is constituted by a push latch mechanism.

11. The head unit according to claim 7, wherein the cap has a liquid absorbent inside.

12. The head unit according to claim 7, wherein the cap has a weir portion for blocking the outflow of the liquid stored inside from the opening when tilted.

13. The head unit according to claim 12, wherein the inside of the cap is divided into two in the depth direction by the weir portion, a liquid for moisturizing is stored in the space on the bottom side with the weir portion interposed therebetween, and the liquid discharged or ejected from the nozzle is recovered in the space on the opening side with the weir portion interposed therebetween.

14. The head unit according to any one of claims 1 to 6, wherein the cap moves between the third position and the fourth position by an arc motion centered on an axis parallel to the arrangement direction of the nozzles, and in a cross section orthogonal to the axis, the portion of the cap closest to the axis is the edge of the cap.

15. The head unit according to any one of claims 1 to 6, further comprising a driving unit for moving the recording head between the first position and the second position.

16. An inkjet recording apparatus comprising: a conveyance unit for conveying a medium; and the head unit according to any one of claims 1 to 6, which ejects ink from the nozzles toward the medium conveyed by the conveyance unit and records an image on the medium.

17. The inkjet recording apparatus according to claim 16, wherein the head unit records an image on the medium in a single pass. ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​

Images